WO2018003492A1 - Paper for energy recovery ventilation element - Google Patents

Paper for energy recovery ventilation element Download PDF

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Publication number
WO2018003492A1
WO2018003492A1 PCT/JP2017/021890 JP2017021890W WO2018003492A1 WO 2018003492 A1 WO2018003492 A1 WO 2018003492A1 JP 2017021890 W JP2017021890 W JP 2017021890W WO 2018003492 A1 WO2018003492 A1 WO 2018003492A1
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WIPO (PCT)
Prior art keywords
cellulose
paper
less
heat exchange
weight
Prior art date
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PCT/JP2017/021890
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French (fr)
Japanese (ja)
Inventor
貴史 川崎
健嗣 藤井
良明 石野
正美 松浦
Original Assignee
日本製紙株式会社
日本製紙パピリア株式会社
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Application filed by 日本製紙株式会社, 日本製紙パピリア株式会社 filed Critical 日本製紙株式会社
Priority to JP2018525028A priority Critical patent/JP6927969B2/en
Publication of WO2018003492A1 publication Critical patent/WO2018003492A1/en

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
    • D21H11/18—Highly hydrated, swollen or fibrillatable fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/10—Coatings without pigments
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F7/00—Ventilation
    • F24F7/04—Ventilation with ducting systems, e.g. by double walls; with natural circulation
    • F24F7/06—Ventilation with ducting systems, e.g. by double walls; with natural circulation with forced air circulation, e.g. by fan positioning of a ventilator in or against a conduit
    • F24F7/08—Ventilation with ducting systems, e.g. by double walls; with natural circulation with forced air circulation, e.g. by fan positioning of a ventilator in or against a conduit with separate ducts for supplied and exhausted air with provisions for reversal of the input and output systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the present invention relates to a total heat exchange element sheet used for a total heat exchanger element that performs heat exchange of both sensible heat and latent heat in a laminated structure heat exchange ventilator used in the air conditioning field.
  • This heat exchanger is composed of a plate-like partition plate having heat conductivity and moisture permeability and a spacing plate that is sandwiched between two partition plates to secure an air flow path, and the partition plates and the spacing plates are stacked in multiple layers. It has a basic structure.
  • the spacing plate is a corrugated plate formed into a sawtooth or sinusoidal waveform, and is sandwiched between partition plates by alternately changing the waveform forming direction in the orthogonal direction. Thereby, it is comprised so that the fluid path
  • the partition plate separates the air supply path that introduces fresh outdoor air into the room and the exhaust path that discharges dirty indoor air to the outdoor, and exchanges sensible heat and latent heat between the air supply and exhaust. It has a function to perform. For this reason, the water vapor permeability indicated by heat conductivity and moisture permeability is essential for the partition plate, and in addition, flame retardance and air shielding properties so that air supply and exhaust do not mix are required.
  • Total heat exchange element paper is used as a material for the partition plate that can meet such requirements, and the following prior art is disclosed.
  • Patent Document 1 discloses a total heat exchanger element paper having moisture absorption / release properties and air shielding properties obtained by impregnating or coating a porous substrate with a mixed solution of a moisture absorbent and a water-soluble polymer substance.
  • Patent Document 2 discloses a total heat exchange element paper that is superior in air shielding and hygroscopicity without using a water-soluble polymer substance by applying a hygroscopic agent to a base paper made from a raw material with a high beating degree. Is disclosed.
  • Patent Document 3 describes a partition member for a heat exchanger having a thickness of 10 to 50 microns and having an excellent air shielding property in which an alkali metal salt is blended with a hygroscopic agent.
  • Patent Document 4 discloses a moisture-absorbing / releasing total heat exchanger paper obtained by mixing microfibrillated cellulose and moisture-absorbing / releasing powder silica gel or aluminum hydroxide into papermaking fibers.
  • Patent Document 5 discloses a total heat exchanger paper using a paper base material using calcium chloride as a hygroscopic agent and blending an antiblocking agent.
  • the total heat exchange element paper a paper in which a porous substrate as described in Patent Document 1 is impregnated or coated with a mixed solution of a hygroscopic agent and a water-soluble polymer substance has been used for the partition member.
  • a part of the water-soluble polymer substance melts and blocks due to moisture absorption, and when corrugating in the element manufacturing process, There is a problem that work efficiency is lowered due to breakage or sticking of a corrugator to a press roll.
  • the base paper has a high beating degree, the water squeezing at the time of papermaking deteriorates and the production efficiency decreases, and the obtained base paper becomes brittle and easily torn, and the workability decreases when producing a heat exchange unit. There is a problem.
  • the total heat exchange element paper containing silica gel and aluminum hydroxide, which are water-insoluble moisture-absorbing and desorbing powders, and adding microfibrillated cellulose as a sealing material is moisture-absorbing and desorbing.
  • the basis weight is increased to 120 g / m 2
  • the air permeability resistance is as low as 200 seconds, and high air shielding properties cannot be obtained.
  • the raw material beaten up to 200 to 600 ml with irregular freeness (according to JIS P8121 except that the amount of collected pulp is 0.3 g) is used as the normal freeness.
  • the beating is so high that the squeezing ability during paper making deteriorates and the production efficiency decreases, and the obtained base paper becomes brittle and easy to tear, and the processability when producing the heat exchange unit May decrease.
  • the total heat exchange element paper obtained by impregnating or coating the base paper with a hygroscopic agent and a water-soluble polymer substance is easily blocked, while the high-beaten base paper is impregnated or coated with the hygroscopic agent.
  • the total heat exchange element paper imparted with moisture absorption / release properties and air shielding by processing has a problem that the production efficiency at the time of papermaking and the workability at the production of the heat exchange unit may be lowered.
  • An object of the present invention is to provide a total heat exchange element sheet having high production efficiency at the time of papermaking, hardly causing problems such as paper breakage at the time of element processing, and having high moisture absorption / release properties and air shielding properties.
  • a total heat exchange element paper comprising papermaking fibers, a hygroscopic agent, and cellulose nanofibers.
  • the papermaking fiber is a cellulose fiber.
  • the cellulose nanofiber is at least one of carboxymethylated cellulose nanofiber, carboxylated cellulose nanofiber, cationized cellulose nanofiber, and esterified cellulose nanofiber.
  • the hygroscopic agent is any one of an alkali metal salt and an alkaline earth metal salt. ⁇ 3.
  • Air permeability resistance is 700 seconds or more.
  • the total heat exchange element paper of the present invention has excellent air permeability resistance and moisture permeability by blending cellulose nanofibers, and can be suitably used for a heat exchanger. Since the total heat exchange element paper of the present invention does not require the use of a high-beating base paper, it can prevent a reduction in production efficiency and a weakening of the base paper by making the base paper high-beating. it can. Further, the total heat exchange element paper of the present invention can reduce the coating amount of the water-soluble polymer substance, and in some cases, the water-soluble polymer substance is unnecessary, so that blocking is difficult to occur, handling property, processing Excellent in properties.
  • Papermaking fiber used as a raw material for the total heat exchange element paper of the present invention is obtained from wood pulp such as softwood pulp and hardwood pulp, flax, abaca, kenaf, bamboo, bagasse and other non-wood raw materials. And cellulose fibers obtained from non-wood pulp and the like. There are no particular restrictions on the method of cooking the cellulose fibers, the presence or absence of bleaching, and the bleaching method. In addition to cellulose fibers, synthetic fibers such as polyester fibers, nylon fibers, rayon fibers, lyocell fibers, and semi-synthetic fibers can be blended for the purpose of improving adhesiveness, dimensional stability, and formability.
  • the pulp used in the present invention is beaten in a range of 100 ml CSF or more and 500 ml CSF or less with Canadian standard freeness described in JIS P8121, more preferably beaten in a range of 200 ml CSF or more and 300 ml CSF or less.
  • Canadian standard freeness is less than 100 ml CSF
  • the paper base is densified and the gaps are reduced.
  • a general beating device such as a beater or a refiner can be used, and there are no particular restrictions on the beating device or beating method.
  • the above beaten pulp contains synthetic or semi-synthetic fiber, filler, colorant, paper strength enhancer, wet strength enhancer, sulfate band, cationized starch, yield improver, etc. as necessary. To be prepared.
  • the above-mentioned stock is made by a general paper making method using a long paper machine, a circular paper machine, a short paper machine, a twin wire paper machine, or a paper machine that combines them.
  • a paper machine that combines them.
  • impregnate flame retardants, rust preventives, anti-blocking agents, etc. with an on-machine coating device such as a size press or roll coater, and apply calendering with a machine calender, super calender, soft nip calender, etc.
  • a base paper is obtained.
  • the air resistance of the base paper is improved by the sealing action of the cellulose nanofibers impregnated or coated on the base paper, but in order to fully exhibit the effect, the air resistance of the base paper itself is 50 seconds. It is necessary that the time is not less than 650 seconds, preferably not less than 150 seconds and not more than 600 seconds, more preferably not less than 200 seconds and not more than 500 seconds. When the air resistance of the base paper is less than 50 seconds, even if cellulose nanofibers are added by impregnation or coating, the air resistance after the addition is small, and the air shielding property of the total heat exchange element paper is insufficient. .
  • the air resistance of the base paper can be adjusted by a normal papermaking technique by changing the degree of beating of the pulp blended as the papermaking fiber and the basis weight of the base paper.
  • the total heat exchange element paper of the present invention can be obtained by impregnating the base paper with a chemical solution containing cellulose nanofibers and a hygroscopic agent, or coating it on at least one side.
  • Cellulose nanofibers are fine fibers obtained by subjecting a cellulose raw material to a chemical modification treatment as necessary, followed by a fibrillation treatment.
  • the average fiber diameter of the cellulose nanofiber is usually about 3 nm to 500 nm.
  • the average fiber diameter and the average fiber length can be obtained by averaging the fiber diameter and the fiber length obtained from the result of observing 30 or more fibers using a field emission scanning electron microscope (FE-SEM). .
  • the average aspect ratio of the cellulose nanofiber is usually 10 or more. Although an upper limit is not specifically limited, Usually, it is 1000 or less.
  • the origin of the cellulose raw material that is the raw material of the cellulose nanofiber is not particularly limited.
  • plants for example, wood, bamboo, hemp, jute, kenaf, farmland waste, cloth, pulp (conifers) Unbleached Kraft Pulp (NUKP), Conifer Bleached Kraft Pulp (NBKP), Hardwood Unbleached Kraft Pulp (LUKP), Hardwood Bleached Kraft Pulp (LBKP), Conifer Unbleached Sulfite Pulp (NUSP), Conifer Bleached Sulfite Pulp (NBSP) ), Thermomechanical pulp (TMP), recycled pulp, waste paper, etc.), animals (for example, ascidians), algae, microorganisms (for example, acetic acid bacteria (acetobacter)), etc.
  • NUKP Unbleached Kraft Pulp
  • NKP Conifer Bleached Kraft Pulp
  • LKP Hardwood Unbleached Kraft Pulp
  • LKP Hardwood
  • the cellulose raw materials used in the present invention are those Either one or a combination of two or more
  • it is a plant or microorganism-derived cellulose raw material (for example, cellulose fiber), and more preferably a plant-derived cellulose raw material (for example, cellulose fiber).
  • the number average fiber diameter of the cellulose raw material is not particularly limited, but in the case of softwood kraft pulp which is a general pulp, it is about 30 ⁇ m to 60 ⁇ m, and in the case of hardwood kraft pulp, it is about 10 ⁇ m to 30 ⁇ m. In the case of other pulps, those that have undergone general refining are about 50 ⁇ m. For example, when a chip or the like having a size of several centimeters is refined, it is preferably adjusted to about 50 ⁇ m by performing mechanical treatment with a disintegrator such as a refiner or beater.
  • a disintegrator such as a refiner or beater.
  • the cellulose raw material has three hydroxyl groups per glucose unit and can be subjected to various chemical modification treatments. In the present invention, these may or may not be modified. However, the chemical modification treatment sufficiently advances the fineness of the fibers, and a uniform fiber length and fiber diameter can be obtained. It is done.
  • the modification method for modifying the cellulose raw material is not particularly limited. For example, chemical modification such as oxidation (carboxylation), etherification (carboxymethylation), cationization, esterification, phosphorylation, silane coupling, fluorination, etc. Is mentioned. Of these, oxidation (carboxylation), etherification (carboxymethylation), cationization, and esterification are preferred. These detailed methods will be described below.
  • the amount of carboxyl groups relative to the absolute dry weight of the obtained oxidized cellulose or cellulose nanofibers is preferably 0.5 mmol / g. As mentioned above, More preferably, it is 0.8 mmol / g or more, More preferably, it is 1.0 mmol / g or more.
  • the upper limit is preferably 3.0 mmol / g or less, more preferably 2.5 mmol / g or less, and still more preferably 2.0 mmol / g or less.
  • the oxidation method is not particularly limited, one example is N-oxyl compound and cellulose in water using an oxidizing agent in the presence of a substance selected from the group consisting of bromide, iodide or a mixture thereof. The method of oxidizing a raw material is mentioned.
  • the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized to produce a group selected from the group consisting of an aldehyde group, a carboxyl group, and a carboxylate group.
  • concentration of the cellulose raw material at the time of reaction is not specifically limited, 5 weight% or less is preferable.
  • N-oxyl compound refers to a compound capable of generating a nitroxy radical.
  • nitroxy radicals include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO).
  • TEMPO 2,2,6,6-tetramethylpiperidine 1-oxyl
  • any compound can be used as long as it promotes the target oxidation reaction.
  • the amount of the N-oxyl compound used is not particularly limited as long as it is a catalyst amount that can oxidize cellulose as a raw material. For example, 0.01 mmol or more is preferable and 0.02 mmol or more is more preferable with respect to 1 g of absolutely dry cellulose.
  • the upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, and even more preferably 0.5 mmol or less.
  • the amount of N-oxyl compound used is preferably 0.01 mmol or more and 10 mmol or less, more preferably 0.01 mmol or more and 1 mmol or less, and further preferably 0.02 mmol or more and 0.5 mmol or less with respect to 1 g of absolutely dry cellulose.
  • Bromide is a compound containing bromine, and examples thereof include alkali metal bromide that can be dissociated and ionized in water, such as sodium bromide.
  • the iodide is a compound containing iodine, and examples thereof include alkali metal iodide. What is necessary is just to select the usage-amount of a bromide or iodide in the range which can accelerate
  • the total amount of bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, with respect to 1 g of absolutely dry cellulose.
  • the upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, and even more preferably 5 mmol or less. Therefore, the total amount of bromide and iodide is preferably 0.1 mmol or more and 100 mmol or less, more preferably 0.1 mmol or more and 10 mmol or less, and further preferably 0.5 mmol or more and 5 mmol or less with respect to 1 g of absolutely dry cellulose.
  • the oxidizing agent is not particularly limited, and examples thereof include halogen, hypohalous acid, halous acid, perhalogen acid, salts thereof, halogen oxide, and peroxide.
  • hypohalous acid or a salt thereof is preferable because it is inexpensive and has a low environmental burden
  • hypochlorous acid or a salt thereof is more preferable
  • sodium hypochlorite is more preferable.
  • the amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, and further preferably 3 mmol or more with respect to 1 g of absolutely dry cellulose.
  • the upper limit is preferably 500 mmol or less, more preferably 50 mmol or less, further preferably 25 mmol or less, and most preferably 10 mmol or less. Therefore, the amount of the oxidizing agent used is preferably 0.5 mmol or more and 500 mmol or less, more preferably 0.5 mmol or more and 50 mmol or less, further preferably 1 mmol or more and 25 mmol or less, and most preferably 3 mmol or more and 10 mmol or less with respect to 1 g of absolutely dry cellulose. preferable.
  • the amount of the oxidizing agent used is preferably 1 mol or more with respect to 1 mol of the N-oxyl compound.
  • the upper limit is preferably 40 mol or less. Therefore, the amount of the oxidizing agent used is preferably 1 mol or more and 40 mol or less with respect to 1 mol of the N-oxyl compound.
  • the conditions such as pH and temperature during the oxidation reaction are not particularly limited, and generally the oxidation reaction proceeds efficiently even under relatively mild conditions.
  • the reaction temperature is preferably 4 ° C or higher, more preferably 15 ° C or higher.
  • the upper limit is preferably 40 ° C. or lower, and more preferably 30 ° C. or lower. Therefore, the temperature is preferably 4 ° C. or higher and 40 ° C. or lower, and may be 15 ° C. or higher and 30 ° C. or lower, that is, room temperature.
  • the pH of the reaction solution is preferably 8 or more, and more preferably 10 or more.
  • the upper limit is preferably 12 or less, and more preferably 11 or less.
  • the pH of the reaction solution is preferably 8 or more and 12 or less, more preferably 10 or more and 11 or less.
  • a carboxyl group is generated in cellulose as the oxidation reaction proceeds, and therefore the pH of the reaction solution tends to decrease. Therefore, in order to advance the oxidation reaction efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution in the above range.
  • the reaction medium for the oxidation is preferably water for reasons such as ease of handling and the difficulty of side reactions.
  • the reaction time in the oxidation can be appropriately set according to the progress of the oxidation, and is usually 0.5 hours or longer.
  • the upper limit is usually 6 hours or less, preferably 4 hours or less. Therefore, the reaction time in oxidation is usually 0.5 hours or more and 6 hours or less, for example 0.5 hours or more and 4 hours or less.
  • Oxidation may be carried out in two or more stages. For example, the oxidized cellulose obtained by filtration after the completion of the first stage reaction is oxidized again under the same or different reaction conditions, thereby preventing the reaction from being inhibited by the salt produced as a by-product in the first stage reaction. Can be oxidized well.
  • Another example of the carboxylation (oxidation) method is a method of oxidizing by ozone treatment.
  • the ozone treatment is usually performed by bringing a gas containing ozone and a cellulose raw material into contact with each other.
  • the ozone concentration in the gas is preferably 50 g / m 3 or more.
  • the upper limit is preferably 250 g / m 3 or less, and more preferably 220 g / m 3 or less.
  • the ozone concentration in the gas is preferably at most 50 g / m 3 or more 250 g / m 3, more preferably at most 50 g / m 3 or more 220 g / m 3.
  • the amount of ozone added is preferably 0.1% by weight or more, and more preferably 5% by weight or more, based on 100% by weight of the solid content of the cellulose raw material.
  • the upper limit is usually 30% by weight or less. Therefore, the amount of ozone added is preferably 0.1% by weight to 30% by weight and more preferably 5% by weight to 30% by weight with respect to 100% by weight of the solid content of the cellulose raw material.
  • the ozone treatment temperature is usually 0 ° C. or higher, preferably 20 ° C. or higher.
  • the upper limit is usually 50 ° C. or lower. Therefore, the ozone treatment temperature is usually 0 ° C. or higher and 50 ° C. or lower, and preferably 20 ° C. or higher and 50 ° C. or lower.
  • the ozone treatment time is usually 1 minute or longer, preferably 30 minutes or longer.
  • the upper limit is usually 360 minutes or less. Therefore, the ozone treatment time is usually from 1 minute to 360 minutes, preferably from 30 minutes to 360 minutes.
  • the resulting product obtained after the ozone treatment may be further oxidized using an oxidizing agent.
  • the oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite; oxygen, hydrogen peroxide, persulfuric acid, peracetic acid and the like.
  • Examples of the method for the additional oxidation treatment include a method in which these oxidizing agents are dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and the cellulose raw material is immersed in the oxidizing agent solution.
  • the amount of the carboxyl group, carboxylate group, and aldehyde group contained in the oxidized cellulose nanofiber can be adjusted by controlling the oxidizing conditions such as the addition amount of the oxidizing agent and the reaction time.
  • An example of a method for measuring the amount of carboxyl groups will be described below. Prepare 60 ml of 0.5 wt% slurry (aqueous dispersion) of oxidized cellulose and add 0.1 M hydrochloric acid aqueous solution to pH 2.5, then add 0.05 N sodium hydroxide aqueous solution dropwise to adjust pH to 11.
  • (2-2-2) Etherified (Carboxymethylated) Cellulose Nanofiber Etherification includes carboxymethyl (ether), methyl (ether), ethyl (ether), cyanoethyl (ether), hydroxyethyl ( Examples include ether), hydroxypropyl (ether), ethylhydroxyethyl (ether), and hydroxypropylmethyl (ether).
  • a carboxymethylation method will be described below.
  • the degree of carboxymethyl group substitution per anhydroglucose unit in the obtained carboxymethylated cellulose or cellulose nanofiber is preferably 0.01 or more, more preferably 0.05 or more, More preferably, it is 0.10 or more.
  • the upper limit is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.35 or less. Therefore, the degree of carboxymethyl group substitution is preferably from 0.01 to 0.50, more preferably from 0.05 to 0.40, and even more preferably from 0.10 to 0.35.
  • the method of carboxymethylation is not particularly limited, and examples thereof include a method of mercerizing a cellulose raw material as a bottoming raw material and then etherifying.
  • the solvent used for the carboxymethylation reaction include water, alcohols (for example, lower alcohols), and mixed solvents thereof.
  • the lower alcohol include methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, and tertiary butanol.
  • the mixing ratio of the lower alcohol in the mixed solvent is usually 60% by weight or more and 95% by weight or less.
  • the amount of the solvent is usually 3 times the weight of the cellulose raw material. Although an upper limit is not specifically limited, It is 20 weight times. Therefore, the amount of the solvent is preferably 3 to 20 times by weight.
  • Mercerization is usually performed by mixing a bottoming raw material and a mercerizing agent.
  • mercerizing agents include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide.
  • the amount of mercerizing agent used is preferably 0.5 times mol or more, more preferably 1.0 times mol or more, and further preferably 1.5 times mol or more per anhydroglucose residue of the starting material.
  • the upper limit is usually 20 times mole or less, preferably 10 times mole or less, and more preferably 5 times mole or less.
  • the mercerization reaction temperature is usually 0 ° C. or higher, preferably 10 ° C. or higher.
  • the upper limit is usually 70 ° C. or lower, preferably 60 ° C. or lower. Therefore, the reaction temperature is usually 0 ° C. or higher and 70 ° C. or lower, preferably 10 ° C. or higher and 60 ° C. or lower.
  • the reaction time is usually 15 minutes or longer, preferably 30 minutes or longer.
  • the upper limit is usually 8 hours or less, preferably 7 hours or less. Therefore, it is usually from 15 minutes to 8 hours, preferably from 30 minutes to 7 hours.
  • the etherification reaction is usually performed by adding a carboxymethylating agent to the reaction system after mercerization.
  • the carboxymethylating agent include sodium monochloroacetate.
  • the addition amount of the carboxymethylating agent is usually preferably 0.05 times mol or more, more preferably 0.5 times mol or more, and further preferably 0.8 times mol or more per glucose residue of the cellulose raw material.
  • the upper limit is usually 10.0 times mol or less, preferably 5 times mol or less, more preferably 3 times mol or less, and thus preferably 0.05 times mol or more and 10.0 times mol or less, more preferably It is 0.5 times mole or more and 5 times mole or less, More preferably, it is 0.8 times mole or more and 3 times mole or less.
  • the reaction temperature is usually 30 ° C. or higher, preferably 40 ° C. or higher, and the upper limit is usually 90 ° C. or lower, preferably 80 ° C. or lower. Accordingly, the reaction temperature is usually 30 ° C. or higher and 90 ° C. or lower, preferably 40 ° C. or higher and 80 ° C. or lower.
  • the reaction time is usually 30 minutes or longer, preferably 1 hour or longer.
  • the upper limit is usually 10 hours or less, preferably 4 hours or less. Therefore, the reaction time is usually from 30 minutes to 10 hours, preferably from 1 hour to 4 hours.
  • the reaction solution may be stirred as necessary during the carboxymethylation reaction.
  • the measurement of the degree of carboxymethyl substitution per glucose unit of carboxymethylated cellulose nanofibers may be performed, for example, by the following method. That is, 1) About 2.0 g of carboxymethylated cellulose (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) Add 100 mL of a solution obtained by adding 100 mL of special grade concentrated nitric acid to 1000 mL of nitric acid methanol and shake for 3 hours to convert the carboxymethylcellulose salt (carboxymethylated cellulose) to hydrogen-type carboxymethylated cellulose.
  • (2-2-3) Cationized cellulose nanofiber When the cellulose raw material is modified by cationization, the resulting cationized cellulose nanofiber has a cation such as ammonium, phosphonium, sulfonium, or a group having the cation in the molecule. It only has to be included.
  • the cationized cellulose nanofiber preferably includes a group having ammonium, and more preferably includes a group having quaternary ammonium.
  • the cationization method is not particularly limited, and examples thereof include a method of reacting a cellulose raw material with a cationizing agent and a catalyst in the presence of water and / or alcohol.
  • the cationizing agent include glycidyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrialkylammonium hydride (eg, 3-chloro-2-hydroxypropyltrimethylammonium hydride) or a halohydrin type thereof. By using any of these, a cationized cellulose having a group containing quaternary ammonium can be obtained.
  • the catalyst include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide.
  • the alcohol examples include alcohols having 1 to 4 carbon atoms.
  • the amount of the cationizing agent is preferably 5% by weight or more, more preferably 10% by weight or more with respect to 100% by weight of the cellulose raw material.
  • the upper limit is usually 800% by weight or less, preferably 500% by weight or less.
  • the amount of the catalyst is preferably 0.5% by weight or more, more preferably 1% by weight or more with respect to 100% by weight of the cellulose fibers.
  • the upper limit is usually 7% by weight or less, preferably 3% by weight or less.
  • the amount of alcohol is preferably 50% by weight or more, more preferably 100% by weight or more, based on 100% by weight of cellulose fibers.
  • the upper limit is usually 50000% by weight or less, preferably 500% by weight or less.
  • the reaction temperature at the time of cationization is usually 10 ° C or higher, preferably 30 ° C or higher, and the upper limit is usually 90 ° C or lower, preferably 80 ° C or lower.
  • the reaction time is usually 10 minutes or longer, preferably 30 minutes or longer.
  • the upper limit is usually 10 hours or less, preferably 5 hours or less.
  • the reaction solution may be stirred as necessary during the cationization reaction.
  • the degree of cation substitution per glucose unit in the cationized cellulose can be adjusted by controlling the amount of cationizing agent added and the composition ratio of water and / or alcohol.
  • the degree of cation substitution refers to the number of substituents introduced per unit structure (glucopyranose ring) constituting cellulose.
  • the degree of cation substitution is defined as “a value obtained by dividing the number of moles of the introduced substituent by the total number of moles of hydroxyl groups of the glucopyranose ring”. Since pure cellulose has three substitutable hydroxyl groups per unit structure (glucopyranose ring), the theoretical maximum value of the degree of cation substitution is 3 (the minimum value is 0).
  • the cation substitution degree per glucose unit of the cationized cellulose nanofiber is preferably 0.01 or more, more preferably 0.02 or more, and further preferably 0.03 or more.
  • the upper limit is preferably 0.40 or less, more preferably 0.30 or less, and further preferably 0.20 or less. Therefore, it is preferably 0.01 or more and 0.40 or less, more preferably 0.02 or more and 0.30 or less, and further preferably 0.03 or more and 0.20 or less.
  • the method of esterification is not particularly limited, and examples thereof include a method of reacting the following compound A with a cellulose raw material.
  • Examples of the method of reacting compound A with a cellulose raw material include a method of mixing a powder or an aqueous solution of compound A with a cellulose raw material, a method of adding an aqueous solution of compound A to a slurry of a cellulose raw material, and the like.
  • a method of mixing an aqueous solution of Compound A into a cellulose raw material or a slurry thereof is preferable.
  • compound A examples include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, and esters thereof.
  • Compound A may be in the form of a salt.
  • a phosphoric acid compound is preferable because it is low in cost and easy to handle, and a phosphoric acid group can be introduced into cellulose of pulp fiber to improve the fibrillation efficiency.
  • the phosphate compound may be any compound having a phosphate group.
  • phosphoric acid sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, diphosphate
  • examples include potassium hydrogen, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium metaphosphate.
  • the phosphoric acid compound used may be one type or a combination of two or more types.
  • phosphoric acid, phosphoric acid sodium salt, phosphoric acid potassium salt, phosphoric acid from the viewpoint that phosphoric acid group introduction efficiency is high, is easy to be defibrated in the following defibrating process, and is industrially applicable.
  • sodium dihydrogen phosphate and disodium hydrogen phosphate are more preferred.
  • the pH of the aqueous solution of the phosphoric acid compound is preferably 7 or less from the viewpoint of increasing the efficiency of introducing phosphate groups, and more preferably pH 3 or more from the viewpoint of suppressing hydrolysis of the pulp fiber.
  • esterification method examples include the following methods.
  • Compound A is added to a suspension of cellulose raw material (for example, solid content concentration of 0.1 to 10% by weight) with stirring to introduce phosphate groups into the cellulose.
  • the amount of compound A added is preferably 0.2 parts by weight or more, more preferably 1 part by weight or more, as the amount of phosphorus element.
  • the upper limit is preferably 500 parts by weight or less, and more preferably 400 parts by weight or less.
  • the yield corresponding to the usage-amount of the compound A can be obtained efficiently. Therefore, it is preferably 0.2 parts by weight or more and 500 parts by weight or less, and more preferably 1 part by weight or more and 400 parts by weight or less.
  • the following compound B may be further added to the reaction system.
  • the method of adding Compound B to the reaction system include a method of adding to a slurry of cellulose raw material, an aqueous solution of Compound A, or a slurry of cellulose raw material and Compound A.
  • Compound B is a nitrogen-containing compound that exhibits basicity. “Show basic” usually means that the aqueous solution of Compound B is pink to red in the presence of a phenolphthalein indicator, or the pH of the aqueous solution of Compound B is greater than 7.
  • the nitrogen-containing compound showing basicity is not particularly limited as long as the effects of the present invention are exhibited, but a compound having an amino group is preferable.
  • urea methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like can be mentioned. Of these, urea is preferable because it is easy to handle at low cost.
  • the amount of Compound B added is preferably 2 parts by weight or more and 1000 parts by weight or less, and more preferably 100 parts by weight or more and 700 parts by weight or less when the cellulose raw material is 100 parts by weight.
  • the reaction temperature is preferably 0 ° C. or higher and 95 ° C. or lower, and more preferably 30 ° C. or higher and 90 ° C. or lower.
  • reaction time is not specifically limited, Usually, it is about 1 minute or more and 600 minutes or less, and 30 minutes or more and 480 minutes or less are preferable. If the conditions for the esterification reaction are in any of these ranges, it is possible to prevent cellulose from being excessively esterified and easily dissolved, and to improve the yield of phosphorylated esterified cellulose. .
  • an esterified cellulose suspension is usually obtained.
  • the esterified cellulose suspension is dehydrated as necessary, and is preferably subjected to heat treatment after dehydration. Thereby, hydrolysis of a cellulose raw material can be suppressed.
  • the heating temperature is preferably 100 ° C. or more and 170 ° C. or less, and is heated at 130 ° C. or less (more preferably 110 ° C. or less) while water is contained in the heat treatment, and after removing water, 100 ° C. or more and 170 ° C. It is more preferable to perform the heat treatment at a temperature not higher than ° C.
  • phosphate esterified cellulose In phosphate esterified cellulose, a phosphate group substituent is introduced into the cellulose raw material, and the cellulose repels electrically. Therefore, phosphorylated esterified cellulose can be easily nano-defibrated.
  • the degree of phosphate group substitution per glucose unit in the phosphate esterified cellulose is preferably 0.001 or more. Thereby, sufficient defibration (for example, nano defibration) can be implemented.
  • the upper limit is preferably 0.40. Thereby, swelling or melt
  • the phosphorylated cellulose is preferably subjected to a washing treatment such as washing with cold water after boiling. Thereby, defibration can be performed efficiently.
  • the cellulose raw material may be defibrated before or after the cellulose raw material is modified. Moreover, defibration may be performed at once or a plurality of times. In the case of multiple times, each defibration period may be any time.
  • the apparatus used for defibration is not particularly limited, and examples thereof include high-speed rotating type, colloid mill type, high-pressure type, roll mill type, ultrasonic type and the like, and high-pressure or ultra-high-pressure homogenizers are preferable, and wet high pressure Or an ultra high pressure homogenizer is more preferable.
  • the apparatus is preferably capable of applying a strong shearing force to the cellulose raw material or modified cellulose (usually a dispersion).
  • the pressure that can be applied by the apparatus is preferably 50 MPa or more, more preferably 100 MPa or more, and still more preferably 140 MPa or more.
  • the apparatus is preferably a wet high-pressure or ultrahigh-pressure homogenizer capable of applying the above pressure to a cellulose raw material or modified cellulose (usually a dispersion) and applying a strong shearing force. Thereby, defibration can be performed efficiently.
  • the solid content concentration of the cellulose raw material in the dispersion is usually 0.1% by weight or more, preferably 0.2% by weight or more, more preferably 0.3%. % By weight or more.
  • the upper limit is usually 10% by weight or less, preferably 6% by weight or less.
  • liquidity can be hold
  • pretreatment may be performed as necessary. The pretreatment may be performed using a mixing, stirring, emulsifying, and dispersing device such as a high-speed shear mixer.
  • cellulose nanofibers may be used in the form of a dispersion, but if necessary, a drying process is carried out to partially or completely remove the solvent, thereby obtaining a wet solid. You may use as a thing or a dry solid.
  • the wet solid is a solid in an intermediate state between the dispersion and the dry solid.
  • the drying treatment may be performed after mixing the water-soluble polymer in the cellulose nanofiber dispersion in advance.
  • water-soluble polymers include cellulose derivatives (carboxymethyl cellulose and salts thereof, methyl cellulose, hydroxypropyl cellulose, ethyl cellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, starch, Snack flour, scrap flour, positive starch, phosphorylated starch, corn starch, gum arabic, locust bean gum, gellan gum, gellan gum, polydextrose, pectin, chitin, water-soluble chitin, chitosan, casein, albumin, soy protein lysate, peptone, polyvinyl Alcohol, polyacrylamide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyamino acid, polylactic acid, polymalic acid, polyg Serine, latex, rosin sizing agent, petroleum resin sizing agent, cellulose
  • the dry solid and wet solid of cellulose nanofibers may be prepared by drying a dispersion of cellulose nanofibers or a mixture of cellulose nanofibers and a water-soluble polymer.
  • a drying method is not specifically limited, For example, spray drying, pressing, air drying, hot air drying, and vacuum drying are mentioned.
  • the drying device include a continuous tunnel drying device, a band drying device, a vertical drying device, a vertical turbo drying device, a multi-stage disk drying device, an aeration drying device, a rotary drying device, an air flow drying device, and a spray dryer drying device.
  • Spray dryers cylindrical dryers, drum dryers, screw conveyor dryers, rotary dryers with heating tubes, vibration transport dryers, batch-type box dryers, vacuum box dryers, stirring dryers, etc.
  • the drying device is preferably a drum drying device.
  • the air shielding property can be enhanced by impregnating or coating the base paper.
  • Preferred coating weight of the cellulose nanofiber is a 0.2 g / m 2 or more 5.0 g / m 2 or less as a solid coating amount per one surface, preferably 0.5 g / m 2 or more 3.0 g / m 2 or less.
  • the coating amount of the cellulose nanofiber is less than 0.2 g / m 2 , the improvement of the air resistance is small and the air shielding property is insufficient.
  • the coating amount exceeds 5.0 g / m 2 , the moisture permeability decreases, which is not preferable.
  • Hygroscopic agent Hygroscopic agents include alkali metal salts such as lithium chloride and sodium lactate, alkaline earth metal salts such as calcium chloride and magnesium chloride, ammonium salts such as ammonium phosphate and ammonium sulfamate, guanidine sulfamate, A guanidine salt such as guanidine hydrochloride can be used, and particularly, calcium chloride which is excellent in hygroscopicity and inexpensive can be preferably used. These compounds may be used alone or in combination of two or more. Moreover, what can be used as a flame retardant among hygroscopic agents can also be mix
  • a preferable coating amount of the hygroscopic agent is 0.5 g / m 2 or more and 20 g / m 2 or less, preferably 1.0 g / m 2 or more and 15 g / m 2 or less.
  • the coating amount of the moisture absorbent is insufficient moisture permeability is less than 0.5 g / m 2.
  • the coating amount exceeds 20 g / m 2 , the moisture absorption amount is excessive, and there is a risk that condensation or a hygroscopic agent may flow out in a high temperature and high humidity environment.
  • the hygroscopic agent may be impregnated on the entire base paper, or may be applied on one side or both sides, as long as it is within the above coating amount range.
  • the total heat exchange element paper of the present invention is obtained by impregnating or coating a base paper composed of papermaking fibers with a chemical solution containing cellulose nanofibers and a chemical solution containing a hygroscopic agent. Can be manufactured.
  • the chemical solution containing cellulose nanofibers and the chemical solution containing a hygroscopic agent are preferably the same chemical solution because the coating amount of each component can be accurately estimated.
  • a chemical solution containing cellulose nanofibers and a hygroscopic agent can be obtained by adding a hygroscopic agent to a dispersion of cellulose nanofibers.
  • the ratio of the hygroscopic agent added to the cellulose nanofiber dispersion is 2 parts by mass or more and 30 parts by mass or less, preferably 5 parts by mass or more and 20 parts by mass or less of the hygroscopic agent with respect to 1 part by mass of the cellulose nanofibers in terms of solid content. Blend. If the amount of the hygroscopic agent is less than 2 parts by mass, sufficient moisture permeability cannot be obtained. Moreover, if the mixing ratio of the hygroscopic agent exceeds 30 parts by mass, the air resistance is insufficient, which is not preferable.
  • the chemical solution of the present invention may contain various commonly used functional auxiliaries such as water-resistant agents, flame retardants, rust inhibitors, antibacterial agents, antibacterial agents, and antiblocking agents. .
  • functional auxiliaries such as water-resistant agents, flame retardants, rust inhibitors, antibacterial agents, antibacterial agents, and antiblocking agents.
  • medical solution may be used for both surfaces, and the chemical
  • the total heat exchange element paper of the present invention can exhibit excellent air resistance by applying cellulose nanofibers.
  • the water-soluble polymer substance can be added as long as blocking does not occur, but the amount is preferably less than 2.0 g / m 2 and more preferably less than 0.5 g / m 2. preferable.
  • the water-soluble polymer substance include polyvinyl alcohol, starch, starch derivatives, polyethylene oxide, alginate, carboxymethylcellulose salt, methylcellulose, and hydroxyethylcellulose.
  • a rod coater As a method for coating a base paper with a chemical solution containing cellulose nanofibers prepared as described above, a rod coater, a die coater, a curtain coater, a 2 roll size press, a rod metalling size press, a gate roll coater, a blade
  • coating with coating machines, such as a coater, and the method of impregnation can be mentioned.
  • the method for drying the wet coating layer is not particularly limited, and various methods such as a steam heating cylinder, a hot air air dryer, a gas heater dryer, an electric heater dryer, and an infrared heater dryer can be used alone or in combination. .
  • the obtained coated paper may be calendered with a super calender, a hot-press roll or the like, if necessary.
  • a super calender a hot-press roll or the like.
  • the calendar treatment By applying the calendar treatment, the thickness is reduced and the thermal conductivity in the thickness direction is improved.
  • the air resistance is increased and the air shielding property is improved.
  • a paper containing papermaking fibers, a hygroscopic agent, and cellulose nanofibers can be obtained.
  • the paper has both air shielding properties and moisture permeability and can be suitably used as a total heat exchange element paper.
  • the basis weight of the total heat exchange element paper is preferably 10 g / m 2 or more and 70 g / m 2 or less, more preferably 15 g / m 2 or more and 40 g / m 2 or less, and most preferably 20 g / m 2 or more and 35 g / m 2. It is as follows. When the basis weight is less than 10 g / m 2 , the strength is remarkably lowered, and workability when processing into a total heat exchange element is lowered. Basis weight unfavorably lowered total heat exchange efficiency in the thickness direction exceeds 70 g / m 2.
  • the thickness of the total heat exchange element paper is preferably 8 ⁇ m or more and 80 ⁇ m or less, and a thinner one in this range is more preferable because the total heat exchange efficiency tends to increase.
  • the thickness is less than 8 ⁇ m, the strength is remarkably lowered, and workability when processing into a total heat exchange element is lowered.
  • the thickness exceeds 80 ⁇ m, the total heat exchange efficiency in the thickness direction is lowered, which is not preferable.
  • the air resistance of the total heat exchange element paper is preferably 700 seconds or more. If the air resistance is less than 700 seconds, there is no significant difference from the air resistance of the base paper, and there is no point in applying cellulose nanofibers. If the air resistance of the heat exchange element paper used in the heat exchange ventilator increases, it becomes difficult to mix air between fresh air supply and dirty exhaust air, and especially the carbon dioxide gas transfer rate decreases. The air shielding property that separates air and exhaust is improved.
  • Patent Document 3 states that when the air permeability resistance is 200 seconds or more, the carbon dioxide gas migration rate is 5% or less, and when the air permeability resistance is 5000 seconds or more, the carbon dioxide gas migration rate can be suppressed to 1% or less. According to Patent Document 5, if the air permeability resistance is 500 seconds or more, it can be used as a total heat exchange element sheet.
  • the moisture permeability of the total heat exchange element paper is preferably 800 g / m 2 ⁇ 24 hr or more, more preferably 1000 g / m 2 ⁇ 24 hr or more.
  • the moisture permeability is effective as an index of the latent heat exchange efficiency of the total heat exchange element paper. The higher the moisture permeability, the higher the latent heat exchange efficiency. On the other hand, the latent heat required when the moisture permeability is less than 800 g / m 2 ⁇ 24 hr. Exchange efficiency cannot be obtained.
  • Basis weight A sample having a size of 250 mm ⁇ 200 mm is placed in a weighing bottle with a known weight, and the weight after drying at 105 ° C. for 2 hours is measured, and the absolute dry weight per square meter of the sample is calculated. The amount was (g / m 2 ).
  • Moisture permeability Measurement was performed by changing the temperature and humidity conditions of the measurement environment using an instrument specified in JIS Z0208 (1976) moisture permeability (cup method).
  • the moisture permeable cup equipped with the test piece is left in a constant temperature and humidity chamber set at 20 ° C. and 65% RH for 24 hours to measure the weight increase, and the weight change per 24 hours of the measurement area of 1 square meter is calculated.
  • the water vapor transmission rate (g / m 2 ⁇ 24 hr) was obtained.
  • Air permeability resistance The average value of five measurements was calculated based on the Oken type testing machine method described in JIS P8117 (2009) Air permeability and air resistance, and the air resistance (king Ken) (seconds).
  • CM-CNF carboxymethylated cellulose nanofibers
  • Example 1 45 parts by mass of water and 17.6 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The above coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • Example 2 Coating is performed by adding 5.52 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass) and dispersing and dissolving with a bladed stirrer. A liquid was prepared. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • Example 3 A total heat exchange element sheet of the present invention was obtained in the same manner as in Example 2 except that the calcium chloride content was 11.7 parts by mass. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • Example 4 30 parts by mass of water and 11.7 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 60 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass) and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, air resistance, and moisture permeability of this paper were measured and shown in Table 1.
  • T-CNF carboxylated cellulose nanofiber
  • Example 5 60 parts by mass of water and 25.2 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 120 parts by mass of an aqueous dispersion of T-CNF (solid concentration: 1.1% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating liquid was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of T-CNF and calcium chloride.
  • this single-sided coated paper On the other side of this single-sided coated paper, 45 parts by mass of water was added to 90 parts by mass of an aqueous T-CNF dispersion (solid content concentration: 1.1% by mass), and the coating liquid dispersed with a bladed stirrer was applied to Meyer. After coating with a bar, the sheet was dried to obtain the total heat exchange element paper of the present invention coated on both sides. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • C-CNF cationized cellulose nanofibers
  • Example 6 45 parts by weight of water and 17.6 parts by weight of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by weight of an aqueous dispersion of C-CNF (solid content concentration: 1.2% by weight) and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of C-CNF and calcium chloride.
  • Example 7 45 parts by mass of water and 17.6 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of CM-CNF and calcium chloride.
  • Example 8 30 parts by weight of water and 3.6 parts by weight of potassium acetate (manufactured by Wako Pure Chemical Industries, Ltd.) were added to 60 parts by weight of an aqueous CM-CNF dispersion (solid content 1.2% by weight), and a bladed stirrer The coating solution was prepared by dispersing and dissolving the solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • Example 9 30 parts by mass of water and 3.6 parts by mass of lithium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were added to 60 parts by mass of an aqueous dispersion of CM-CNF (solid content concentration 1.2% by mass), and a bladed stirrer The coating solution was prepared by dispersing and dissolving the solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • One end in the longitudinal direction of the bonded test piece is peeled off slightly, and one end is sandwiched between sample grips attached to a digital force gauge (manufactured by Nidec Shinpo Co., Ltd., device name: FGP-0.5 type), The other end of the sheet was grasped by hand and pulled, peeled about 70 mm in the longitudinal direction, and the maximum value of the peel resistance was read to obtain the peel resistance per 5 cm of the sample width.
  • the peel resistance of the test piece force-bonded using a hot-press roll was 50 g / 5 cm or less, and the blocking property was evaluated to be extremely weak. Moreover, also in the blocking properties of the other examples, a part of the pressure-bonding did not peel off, and the base material was not destroyed.
  • Example 1 A total heat exchange element paper of the present invention was obtained in the same manner as in Example 1 except that CM-CNF was not used. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • the base paper had a thin paper thickness due to densification by calendering, and the air resistance was high. However, the density, thickness, and air resistance were calendered by the wet and dry action during the coating process. Returning to the previous state, the paper thickness was thick and the air resistance was low.
  • ⁇ Comparative example 2> A total heat exchange element paper was obtained in the same manner as in Example 1 except that calcium chloride was not added and the amount of CM-CNF adhered was 0.3 g / m 2 . The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
  • the amount of moisture absorbent applied to this paper was 2.5 g / m 2 in terms of solid content, and the amount of polyvinyl alcohol applied was 3.5 g / m 2 in terms of solid content.
  • the air permeation resistance was 23000 seconds, and the water vapor transmission rate was 1200 g / m 2 ⁇ 24 hr, and had sufficient air shielding and moisture permeability as a total heat exchange element paper.
  • the paper was subjected to a forced pressure bonding test using a hot-pressing roll in the same manner as in the evaluation of the blocking property, and the peel resistance was measured. As a result, the peel resistance was as extremely high as 300 g / cm or more, and part of the mother was not peeled off. Since the material was broken, it was evaluated that the blocking property was very strong.

Abstract

The problem addressed by the present invention is to provide paper for an energy recovery ventilation element that can be produced efficiency during paper making, in which problems such as torn paper do not arise easily during element processing, and that has high moisture absorption and desorption and air shielding properties. To address the problem, provided is paper for an energy recovery ventilation element that includes fiber for paper-making, a moisture absorbent, and cellulose nanofiber.

Description

全熱交換素子用紙Total heat exchange element paper
　本発明は、空調分野で使用される積層構造の熱交換換気装置において、顕熱と潜熱の双方の熱交換を行う全熱交換器素子に使用する全熱交換素子用紙に関する。 The present invention relates to a total heat exchange element sheet used for a total heat exchanger element that performs heat exchange of both sensible heat and latent heat in a laminated structure heat exchange ventilator used in the air conditioning field.
　近年、冷房や暖房などの空調機器の普及に伴い、換気の際に給気と排気との間で熱交換して温度及び湿度を回収できる換気用熱交換器が使用されている。
　この熱交換器は、伝熱性と透湿性とを有する平板状の仕切板と２枚の仕切板の間に挟んで空気流路を確保する間隔板からなり、仕切板と間隔板を複数層に重ね合わせた基本構造を有している。間隔板は鋸波状又は正弦波状の波形に成形された波板であり、その波形の成形方向を直交方向へ交互に変えて仕切板の間に挟着されている。これにより、間隔板と仕切板から構成される各層間に、二系統の流体通路が一層おきに交互に直交するように構成されている。 In recent years, with the widespread use of air conditioning equipment such as cooling and heating, ventilation heat exchangers that can recover temperature and humidity by exchanging heat between air supply and exhaust during ventilation have been used.
This heat exchanger is composed of a plate-like partition plate having heat conductivity and moisture permeability and a spacing plate that is sandwiched between two partition plates to secure an air flow path, and the partition plates and the spacing plates are stacked in multiple layers. It has a basic structure. The spacing plate is a corrugated plate formed into a sawtooth or sinusoidal waveform, and is sandwiched between partition plates by alternately changing the waveform forming direction in the orthogonal direction. Thereby, it is comprised so that the fluid path | route of a 2 system | strain may be orthogonally crossed alternately every other layer between each layer comprised from a space | interval board and a partition plate.
　仕切板は室外の新鮮な空気を室内に導入する給気経路と、汚れた室内の空気を室外に排出する排気経路を分離し、給気と排気の間で顕熱と同時に潜熱の熱交換を行う機能を有するものである。このため、仕切板には伝熱性と透湿度で示される水蒸気透過性が必須であり、加えて難燃性や給気と排気が交じり合わないような空気遮蔽性が必要とされている。 The partition plate separates the air supply path that introduces fresh outdoor air into the room and the exhaust path that discharges dirty indoor air to the outdoor, and exchanges sensible heat and latent heat between the air supply and exhaust. It has a function to perform. For this reason, the water vapor permeability indicated by heat conductivity and moisture permeability is essential for the partition plate, and in addition, flame retardance and air shielding properties so that air supply and exhaust do not mix are required.
　このような要求に対応できる仕切板の素材として全熱交換素子用紙が用いられており、下記のような従来技術が開示されている。
　特許文献１には、多孔質基材に吸湿剤と水溶性高分子物質の混合溶液を含浸若しくは塗布することにより得られる吸放湿性と空気遮蔽性を有する全熱交換器エレメント用紙が開示されている。
　特許文献２には、高叩解度の原料を抄紙した基紙に吸湿剤を塗工使用することで、水溶性高分子物質を用いずに空気遮蔽性と吸湿性の優れた全熱交換素子用紙が得られることが開示されている。
　特許文献３には、吸湿剤にアルカリ金属塩を配合した厚さ１０～５０ミクロンの空気遮蔽性の優れた熱交換器用仕切部材が記載されている。
　特許文献４には、製紙用繊維にミクロフィブリル化セルロースと吸放湿性粉体であるシリカゲルや水酸化アルミニウムを配合してなる吸放湿性を有する全熱交換器用紙が開示されている。
　特許文献５には、吸湿剤に塩化カルシウムを使用し、ブロッキング防止剤を配合した紙基材を用いた全熱交換器用紙が開示されている。 Total heat exchange element paper is used as a material for the partition plate that can meet such requirements, and the following prior art is disclosed.
Patent Document 1 discloses a total heat exchanger element paper having moisture absorption / release properties and air shielding properties obtained by impregnating or coating a porous substrate with a mixed solution of a moisture absorbent and a water-soluble polymer substance. Yes.
Patent Document 2 discloses a total heat exchange element paper that is superior in air shielding and hygroscopicity without using a water-soluble polymer substance by applying a hygroscopic agent to a base paper made from a raw material with a high beating degree. Is disclosed.
Patent Document 3 describes a partition member for a heat exchanger having a thickness of 10 to 50 microns and having an excellent air shielding property in which an alkali metal salt is blended with a hygroscopic agent.
Patent Document 4 discloses a moisture-absorbing / releasing total heat exchanger paper obtained by mixing microfibrillated cellulose and moisture-absorbing / releasing powder silica gel or aluminum hydroxide into papermaking fibers.
Patent Document 5 discloses a total heat exchanger paper using a paper base material using calcium chloride as a hygroscopic agent and blending an antiblocking agent.
特公昭５８－４６３２５号公報Japanese Examined Patent Publication No. 58-46325 国際公開第２００２／０９９１９３号International Publication No. 2002/099193 特開２００３－１４８８９２号公報Japanese Patent Laid-Open No. 2003-148892 特開平１１－１８９９９９号公報Japanese Patent Laid-Open No. 11-189999 特開２００７－１１９９６９号公報JP 2007-119969 A
　従来、全熱交換素子用紙として、特許文献１に記載されているような多孔質基材に吸湿剤と水溶性高分子物質の混合溶液を含浸若しくは塗布した用紙が仕切部材に使用されてきたが、夏期などの温度と湿度が高い条件下では、吸湿により水溶性高分子物質の一部が溶けてブロッキングする現象がおき、エレメント製造工程でコルゲート加工する際、原紙巻取の巻き戻し作業時の破断やコルゲーターのプレスロールへの貼り付きにより作業効率が低下するという問題点がある。 Conventionally, as the total heat exchange element paper, a paper in which a porous substrate as described in Patent Document 1 is impregnated or coated with a mixed solution of a hygroscopic agent and a water-soluble polymer substance has been used for the partition member. Under high temperature and humidity conditions such as summer, a part of the water-soluble polymer substance melts and blocks due to moisture absorption, and when corrugating in the element manufacturing process, There is a problem that work efficiency is lowered due to breakage or sticking of a corrugator to a press roll.
　また、特許文献２や特許文献３に記載されているような高叩解度の原料を用いて空気遮蔽性を高めた基紙に吸湿剤を添加した用紙は、基紙が緻密で空気が透過し難いため、水溶性高分子物質を含浸または塗工して空気遮蔽性を付与する必要が無く、吸湿剤や難燃剤からなる薬液を含浸または塗工することで吸放湿性と空気遮蔽性を有する全熱交換素子用紙が得られる。しかし、基紙を高叩解度にすると抄紙時の搾水性が悪くなり生産効率が低下する上、得られた基紙が脆弱で裂け易くなり、熱交換ユニットを生産する際に加工性が低下するという問題がある。 In addition, a paper in which a moisture absorbent is added to a base paper that has been improved in air shielding properties using a raw material having a high beating degree as described in Patent Document 2 and Patent Document 3, and the base paper is dense and allows air to pass therethrough. Because it is difficult, it is not necessary to impregnate or apply a water-soluble polymer substance to provide air shielding properties, and it has moisture absorption and desorption properties and air shielding properties by impregnating or applying a chemical solution comprising a hygroscopic agent or a flame retardant. A total heat exchange element paper is obtained. However, if the base paper has a high beating degree, the water squeezing at the time of papermaking deteriorates and the production efficiency decreases, and the obtained base paper becomes brittle and easily torn, and the workability decreases when producing a heat exchange unit. There is a problem.
　特許文献４に記載されているように、水不溶性の吸放湿性粉体であるシリカゲルや水酸化アルミニウムを配合し、目止め材としてミクロフィブリル化セルロースを添加した全熱交換素子用紙は吸放湿性を有するものの、坪量を１２０ｇ／ｍ2まで増しても透気抵抗度が２００秒と低く、高度な空気遮蔽性を得ることができない。 As described in Patent Document 4, the total heat exchange element paper containing silica gel and aluminum hydroxide, which are water-insoluble moisture-absorbing and desorbing powders, and adding microfibrillated cellulose as a sealing material is moisture-absorbing and desorbing. However, even if the basis weight is increased to 120 g / m 2, the air permeability resistance is as low as 200 seconds, and high air shielding properties cannot be obtained.
　特許文献５に記載されているように、基材を構成するパルプを変則フリーネス（パルプ採取量を０．３ｇとした以外はＪＩＳ　Ｐ８１２１に準ずる）で２００～６００ｍｌまで叩解した原料は、通常のフリーネス測定方法では測定困難なほど高叩解であるため、抄紙時の搾水性が悪くなり生産効率が低下する上、得られた基紙が脆弱で裂け易くなり、熱交換ユニットを生産する際に加工性が低下する恐れがある。 As described in Patent Document 5, the raw material beaten up to 200 to 600 ml with irregular freeness (according to JIS P8121 except that the amount of collected pulp is 0.3 g) is used as the normal freeness. As the measurement method is difficult to measure, the beating is so high that the squeezing ability during paper making deteriorates and the production efficiency decreases, and the obtained base paper becomes brittle and easy to tear, and the processability when producing the heat exchange unit May decrease.
　以上のように、基紙へ吸湿剤と水溶性高分子物質を含浸または塗工することにより得られる全熱交換素子用紙はブロッキングし易く、一方、高叩解の基紙に吸湿剤を含浸または塗工することにより吸放湿性と空気遮蔽性を付与した全熱交換素子用紙は抄紙時の生産効率や熱交換ユニット生産時の加工性が低下する恐れがあるという問題がある。 As described above, the total heat exchange element paper obtained by impregnating or coating the base paper with a hygroscopic agent and a water-soluble polymer substance is easily blocked, while the high-beaten base paper is impregnated or coated with the hygroscopic agent. The total heat exchange element paper imparted with moisture absorption / release properties and air shielding by processing has a problem that the production efficiency at the time of papermaking and the workability at the production of the heat exchange unit may be lowered.
　本発明は、抄紙時の生産効率が高く、エレメント加工時に断紙などの問題が発生し難く、吸放湿性と空気遮蔽性が高い全熱交換素子用紙を提供することを課題とする。 An object of the present invention is to provide a total heat exchange element sheet having high production efficiency at the time of papermaking, hardly causing problems such as paper breakage at the time of element processing, and having high moisture absorption / release properties and air shielding properties.
　本発明者等は、鋭意研究の結果、前記課題を解決した新規な全熱交換素子用紙を開発した。
　本発明の課題を解決するための手段は、以下のとおりである。
１．製紙用繊維、吸湿剤、セルロースナノファイバーを含有することを特徴とする全熱交換素子用紙。
２．前記製紙用繊維が、セルロース繊維であることを特徴とする１．に記載の全熱交換素子用紙。
３．前記セルロースナノファイバーが、カルボキシメチル化セルロースナノファイバー、カルボキシル化セルロースナノファイバー、カチオン化セルロースナノファイバー、エステル化セルロースナノファイバーの少なくとも一種であることを特徴とする１．または２．に記載の全熱交換素子用紙。
４．前記吸湿剤が、アルカリ金属塩、アルカリ土類金属塩のいずれかであることを特徴とする１．～３．のいずれかに記載の全熱交換素子用紙。
５．透気抵抗度が７００秒以上であることを特徴とする１．～４．のいずれかに記載の全熱交換素子用紙。
６．製紙用繊維からなる基紙の少なくとも片面に、吸湿剤とセルロースナノファイバーとを含有する薬液を塗工することを特徴とする全熱交換素子用紙の製造方法。 As a result of intensive studies, the present inventors have developed a novel total heat exchange element paper that has solved the above-mentioned problems.
Means for solving the problems of the present invention are as follows.
1. A total heat exchange element paper comprising papermaking fibers, a hygroscopic agent, and cellulose nanofibers.
2. The papermaking fiber is a cellulose fiber. The total heat exchange element paper described in 1.
3. The cellulose nanofiber is at least one of carboxymethylated cellulose nanofiber, carboxylated cellulose nanofiber, cationized cellulose nanofiber, and esterified cellulose nanofiber. Or 2. The total heat exchange element paper described in 1.
4). The hygroscopic agent is any one of an alkali metal salt and an alkaline earth metal salt. ~ 3. The total heat exchange element paper according to any one of the above.
5. 1. Air permeability resistance is 700 seconds or more. ~ 4. The total heat exchange element paper according to any one of the above.
6). A method for producing a total heat exchange element paper, wherein a chemical solution containing a hygroscopic agent and cellulose nanofibers is applied to at least one surface of a base paper made of papermaking fibers.
　本発明の全熱交換素子用紙は、セルロースナノファイバーを配合することにより、優れた透気抵抗度と透湿度とを有し、熱交換器に好適に利用することができる。本発明の全熱交換素子用紙は、高叩解である基紙を使用する必要が無いため、基紙を高叩解にすることによる抄紙時の生産効率低下や、基紙の脆弱化を防ぐことができる。また、本発明の全熱交換素子用紙は、水溶性高分子物質の塗工量を少なくすることができ、場合によっては水溶性高分子物質が不要なため、ブロッキングが起こりにくく、取扱性、加工性に優れる。 The total heat exchange element paper of the present invention has excellent air permeability resistance and moisture permeability by blending cellulose nanofibers, and can be suitably used for a heat exchanger. Since the total heat exchange element paper of the present invention does not require the use of a high-beating base paper, it can prevent a reduction in production efficiency and a weakening of the base paper by making the base paper high-beating. it can. Further, the total heat exchange element paper of the present invention can reduce the coating amount of the water-soluble polymer substance, and in some cases, the water-soluble polymer substance is unnecessary, so that blocking is difficult to occur, handling property, processing Excellent in properties.
　以下に、本発明における実施の形態を詳細に説明する。
（１）製紙用繊維
　本発明の全熱交換素子用紙の原料として使用する製紙用繊維は、針葉樹パルプ、広葉樹パルプ等の木材パルプ、亜麻、アバカ、ケナフ、竹、バガスなどの非木材原料から得られる非木材パルプ等から得られるセルロース繊維が挙げられる。セルロース繊維の蒸解方法や漂白の有無および漂白方法は特に限定されない。また、セルロース繊維の他に、接着性、寸法安定性、賦形性向上などの目的でポリエステル繊維、ナイロン繊維、レーヨン繊維、リヨセル繊維などの合成繊維や半合成繊維を配合することができる。 Hereinafter, embodiments of the present invention will be described in detail.
(1) Papermaking fiber The papermaking fiber used as a raw material for the total heat exchange element paper of the present invention is obtained from wood pulp such as softwood pulp and hardwood pulp, flax, abaca, kenaf, bamboo, bagasse and other non-wood raw materials. And cellulose fibers obtained from non-wood pulp and the like. There are no particular restrictions on the method of cooking the cellulose fibers, the presence or absence of bleaching, and the bleaching method. In addition to cellulose fibers, synthetic fibers such as polyester fibers, nylon fibers, rayon fibers, lyocell fibers, and semi-synthetic fibers can be blended for the purpose of improving adhesiveness, dimensional stability, and formability.
　本発明で使用するパルプは、ＪＩＳ　Ｐ８１２１記載のカナダ標準ろ水度で１００ｍｌＣＳＦ以上５００ｍｌＣＳＦ以下の範囲に叩解し、より好ましくは２００ｍｌＣＳＦ以上３００ｍｌＣＳＦ以下の範囲に叩解して使用する。カナダ標準ろ水度が１００ｍｌＣＳＦ未満の場合は、紙匹が緻密化して空隙が少なくなり、全熱交換素子用紙の基紙として用いた場合に塗工剤が紙中に浸透し難くなって基紙表面に吸湿剤等が局在化するためブロッキングし易くなること、および湿度変化による伸縮量が大きくなることなどの問題が発生し好ましくない。また、カナダ標準ろ水度が５００ｍｌＣＳＦを越えると紙匹の空隙量や空隙径が増大してセルロースナノファイバーによる空気遮蔽効果が不十分となるため好ましくない。パルプの叩解は、ビーター、リファイナー等の一般的な叩解装置が使用でき、叩解装置や叩解方法に特段の制限はない。 The pulp used in the present invention is beaten in a range of 100 ml CSF or more and 500 ml CSF or less with Canadian standard freeness described in JIS P8121, more preferably beaten in a range of 200 ml CSF or more and 300 ml CSF or less. When the Canadian standard freeness is less than 100 ml CSF, the paper base is densified and the gaps are reduced. When used as the base paper for all heat exchange element paper, it is difficult for the coating agent to penetrate into the paper. Since a hygroscopic agent or the like is localized on the surface, problems such as easy blocking and an increase in the amount of expansion / contraction due to a change in humidity occur. In addition, if the Canadian standard freeness exceeds 500 ml CSF, the amount of voids and the diameter of the paper web increase and the air shielding effect by cellulose nanofibers becomes insufficient, which is not preferable. For beating the pulp, a general beating device such as a beater or a refiner can be used, and there are no particular restrictions on the beating device or beating method.
　抄紙用の紙料は、上記叩解パルプへ必要に応じて合成または半合成繊維、填料、色料、紙力増強剤、湿潤紙力増強剤、硫酸バンド、カチオン化デンプン、歩留り向上剤等を配合して調成される。 For papermaking, the above beaten pulp contains synthetic or semi-synthetic fiber, filler, colorant, paper strength enhancer, wet strength enhancer, sulfate band, cationized starch, yield improver, etc. as necessary. To be prepared.
　上記紙料は、長網式抄紙機、円網式抄紙機、短網式抄紙機、ツインワイヤー式抄紙機やそれらを組み合せた抄紙機等を用い、一般的な抄紙方法で抄造され、抄紙機や抄紙方法に特段の制限はない。また、必要に応じてサイズプレスやロールコーター等のオンマシン塗工装置で難燃剤、防錆剤、ブロッキング防止剤等を含浸し、マシンカレンダー、スーパーカレンダー、ソフトニップカレンダー等でカレンダー処理を施すことで、基紙が得られる。 The above-mentioned stock is made by a general paper making method using a long paper machine, a circular paper machine, a short paper machine, a twin wire paper machine, or a paper machine that combines them. There are no particular restrictions on the paper making method. If necessary, impregnate flame retardants, rust preventives, anti-blocking agents, etc. with an on-machine coating device such as a size press or roll coater, and apply calendering with a machine calender, super calender, soft nip calender, etc. A base paper is obtained.
　基紙の透気抵抗度は、基紙に含浸または塗工されるセルロースナノファイバーの目止め作用により向上するが、その効果を十分発揮させるために、基紙自体の透気抵抗度を５０秒以上６５０秒以下、好ましくは１５０秒以上６００秒以下、より好ましくは２００秒以上５００秒以下とすることが必要である。基紙の透気抵抗度が５０秒未満では含浸または塗工によりセルロースナノファイバーを添加しても、添加後の透気抵抗度の増加が少なく、全熱交換素子用紙の空気遮蔽性が不足する。基紙の透気抵抗度が６５０秒を越えると、含浸または塗工された薬液が基紙の内部へ浸透し難くなり、基紙表面付近の薬液成分によるブロッキングが発生し易くなるため好ましくない。基紙の透気抵抗度は、製紙用繊維として配合するパルプの叩解の程度や基紙の坪量を変えることにより、通常の抄紙技術で調整することができる。 The air resistance of the base paper is improved by the sealing action of the cellulose nanofibers impregnated or coated on the base paper, but in order to fully exhibit the effect, the air resistance of the base paper itself is 50 seconds. It is necessary that the time is not less than 650 seconds, preferably not less than 150 seconds and not more than 600 seconds, more preferably not less than 200 seconds and not more than 500 seconds. When the air resistance of the base paper is less than 50 seconds, even if cellulose nanofibers are added by impregnation or coating, the air resistance after the addition is small, and the air shielding property of the total heat exchange element paper is insufficient. . When the air permeability resistance of the base paper exceeds 650 seconds, the impregnated or coated chemical solution is difficult to penetrate into the base paper and blocking due to the chemical component near the base paper surface is not preferable. The air resistance of the base paper can be adjusted by a normal papermaking technique by changing the degree of beating of the pulp blended as the papermaking fiber and the basis weight of the base paper.
　本発明の全熱交換素子用紙は、前記基紙にセルロースナノファイバーと吸湿剤とを含有する薬液を含浸または少なくとも片面に塗工して得られる。 The total heat exchange element paper of the present invention can be obtained by impregnating the base paper with a chemical solution containing cellulose nanofibers and a hygroscopic agent, or coating it on at least one side.
（２）セルロースナノファイバー
　セルロースナノファイバーは、セルロース原料を、必要に応じ化学変性処理した後で、解繊処理することにより得られる微細繊維である。セルロースナノファイバーの平均繊維径は、通常３ｎｍ以上５００ｎｍ以下程度である。平均繊維径及び平均繊維長は、電界放出型走査電子顕微鏡（ＦＥ－ＳＥＭ）を用いて、３０本以上の繊維を観察した結果から得られる繊維径及び繊維長を平均することによって得ることができる。
　セルロースナノファイバーの平均アスペクト比は、通常１０以上である。上限は特に限定されないが、通常は１０００以下である。平均アスペクト比は、下記の式により算出することができる。
　　平均アスペクト比＝平均繊維長／平均繊維径 (2) Cellulose nanofibers Cellulose nanofibers are fine fibers obtained by subjecting a cellulose raw material to a chemical modification treatment as necessary, followed by a fibrillation treatment. The average fiber diameter of the cellulose nanofiber is usually about 3 nm to 500 nm. The average fiber diameter and the average fiber length can be obtained by averaging the fiber diameter and the fiber length obtained from the result of observing 30 or more fibers using a field emission scanning electron microscope (FE-SEM). .
The average aspect ratio of the cellulose nanofiber is usually 10 or more. Although an upper limit is not specifically limited, Usually, it is 1000 or less. The average aspect ratio can be calculated by the following formula.
Average aspect ratio = average fiber length / average fiber diameter
（２－１）セルロース原料
　セルロースナノファイバーの原料であるセルロース原料の由来は、特に限定されないが、例えば、植物（例えば、木材、竹、麻、ジュート、ケナフ、農地残廃物、布、パルプ（針葉樹未漂白クラフトパルプ（ＮＵＫＰ）、針葉樹漂白クラフトパルプ（ＮＢＫＰ）、広葉樹未漂白クラフトパルプ（ＬＵＫＰ）、広葉樹漂白クラフトパルプ（ＬＢＫＰ）、針葉樹未漂白サルファイトパルプ（ＮＵＳＰ）、針葉樹漂白サルファイトパルプ（ＮＢＳＰ）、サーモメカニカルパルプ（ＴＭＰ）、再生パルプ、古紙等）、動物（例えばホヤ類）、藻類、微生物（例えば酢酸菌（アセトバクター））等が挙げられる。本発明で用いるセルロース原料は、これらのいずれかであってもよいし２種類以上の組み合わせであってもよいが、好ましくは植物又は微生物由来のセルロース原料（例えば、セルロース繊維）であり、より好ましくは植物由来のセルロース原料（例えば、セルロース繊維）である。
　セルロース原料の数平均繊維径は特に制限されないが、一般的なパルプである針葉樹クラフトパルプの場合は３０μｍ以上６０μｍ以下程度、広葉樹クラフトパルプの場合は１０μｍ以上３０μｍ以下程度である。その他のパルプの場合、一般的な精製を経たものは５０μｍ程度である。例えばチップ等の数ｃｍ大のものを精製したものである場合、リファイナー、ビーター等の離解機で機械的処理を行い、５０μｍ程度に調整することが好ましい。 (2-1) Cellulose raw material The origin of the cellulose raw material that is the raw material of the cellulose nanofiber is not particularly limited. For example, plants (for example, wood, bamboo, hemp, jute, kenaf, farmland waste, cloth, pulp (conifers) Unbleached Kraft Pulp (NUKP), Conifer Bleached Kraft Pulp (NBKP), Hardwood Unbleached Kraft Pulp (LUKP), Hardwood Bleached Kraft Pulp (LBKP), Conifer Unbleached Sulfite Pulp (NUSP), Conifer Bleached Sulfite Pulp (NBSP) ), Thermomechanical pulp (TMP), recycled pulp, waste paper, etc.), animals (for example, ascidians), algae, microorganisms (for example, acetic acid bacteria (acetobacter)), etc. The cellulose raw materials used in the present invention are those Either one or a combination of two or more Preferably, it is a plant or microorganism-derived cellulose raw material (for example, cellulose fiber), and more preferably a plant-derived cellulose raw material (for example, cellulose fiber).
The number average fiber diameter of the cellulose raw material is not particularly limited, but in the case of softwood kraft pulp which is a general pulp, it is about 30 μm to 60 μm, and in the case of hardwood kraft pulp, it is about 10 μm to 30 μm. In the case of other pulps, those that have undergone general refining are about 50 μm. For example, when a chip or the like having a size of several centimeters is refined, it is preferably adjusted to about 50 μm by performing mechanical treatment with a disintegrator such as a refiner or beater.
（２－２）変性
　セルロース原料は、グルコース単位あたり３つのヒドロキシル基を有しており、各種の化学変性処理を行うことが可能である。本発明では、これらに対して変性を行ってもよく、また行わなくてもよいが、化学変性処理を行った方が、繊維の微細化が十分に進み、均一な繊維長及び繊維径が得られる。
　セルロース原料を変性するための変性方法は特に制限されないが、例えば、酸化（カルボキシル化）、エーテル化（カルボキシメチル化）、カチオン化、エステル化、リン酸化、シランカップリング、フッ素化などの化学変性が挙げられる。中でも、酸化（カルボキシル化）、エーテル化（カルボキシメチル化）、カチオン化、エステル化が好ましく、以下ではこれらの詳細な方法について説明する。 (2-2) Modification The cellulose raw material has three hydroxyl groups per glucose unit and can be subjected to various chemical modification treatments. In the present invention, these may or may not be modified. However, the chemical modification treatment sufficiently advances the fineness of the fibers, and a uniform fiber length and fiber diameter can be obtained. It is done.
The modification method for modifying the cellulose raw material is not particularly limited. For example, chemical modification such as oxidation (carboxylation), etherification (carboxymethylation), cationization, esterification, phosphorylation, silane coupling, fluorination, etc. Is mentioned. Of these, oxidation (carboxylation), etherification (carboxymethylation), cationization, and esterification are preferred. These detailed methods will be described below.
（２－２－１）酸化（カルボキシル化）セルロースナノファイバー
　酸化によりセルロース原料を変性する場合、得られる酸化セルロース又はセルロースナノファイバーの絶乾重量に対するカルボキシル基の量は、好ましくは０．５ｍｍｏｌ／ｇ以上、より好ましくは０．８ｍｍｏｌ／ｇ以上、さらに好ましくは１．０ｍｍｏｌ／ｇ以上である。上限は、好ましくは３．０ｍｍｏｌ／ｇ以下、より好ましくは２．５ｍｍｏｌ／ｇ以下、さらに好ましくは２．０ｍｍｏｌ／ｇ以下である。従って、０．５ｍｍｏｌ／ｇ以上３．０ｍｍｏｌ／ｇ以下が好ましく、０．８ｍｍｏｌ／ｇ以上２．５ｍｍｏｌ／ｇ以下がより好ましく、１．０ｍｍｏｌ／ｇ以上２．０ｍｍｏｌ／ｇ以下がさらに好ましい。
　酸化の方法は特に限定されないが、１つの例としては、Ｎ－オキシル化合物、及び、臭化物、ヨウ化物若しくはこれらの混合物からなる群より選択される物質の存在下で酸化剤を用いて水中でセルロース原料を酸化する方法が挙げられる。この方法によれば、セルロース表面のグルコピラノース環のＣ６位の一級水酸基が選択的に酸化され、アルデヒド基、カルボキシル基、及びカルボキシレート基からなる群より選ばれる基が生じる。反応時のセルロース原料の濃度は特に限定されないが、５重量％以下が好ましい。 (2-2-1) Oxidized (carboxylated) cellulose nanofibers When the cellulose raw material is modified by oxidation, the amount of carboxyl groups relative to the absolute dry weight of the obtained oxidized cellulose or cellulose nanofibers is preferably 0.5 mmol / g. As mentioned above, More preferably, it is 0.8 mmol / g or more, More preferably, it is 1.0 mmol / g or more. The upper limit is preferably 3.0 mmol / g or less, more preferably 2.5 mmol / g or less, and still more preferably 2.0 mmol / g or less. Therefore, 0.5 mmol / g or more and 3.0 mmol / g or less is preferable, 0.8 mmol / g or more and 2.5 mmol / g or less is more preferable, and 1.0 mmol / g or more and 2.0 mmol / g or less is more preferable.
Although the oxidation method is not particularly limited, one example is N-oxyl compound and cellulose in water using an oxidizing agent in the presence of a substance selected from the group consisting of bromide, iodide or a mixture thereof. The method of oxidizing a raw material is mentioned. According to this method, the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized to produce a group selected from the group consisting of an aldehyde group, a carboxyl group, and a carboxylate group. Although the density | concentration of the cellulose raw material at the time of reaction is not specifically limited, 5 weight% or less is preferable.
　Ｎ－オキシル化合物とは、ニトロキシラジカルを発生しうる化合物をいう。ニトロキシラジカルとしては例えば、２，２，６，６－テトラメチルピペリジン１－オキシル（ＴＥＭＰＯ）が挙げられる。Ｎ－オキシル化合物としては、目的の酸化反応を促進する化合物であれば、いずれの化合物も使用できる。
　Ｎ－オキシル化合物の使用量は、原料となるセルロースを酸化できる触媒量であれば特に制限されない。例えば、絶乾１ｇのセルロースに対して、０．０１ｍｍｏｌ以上が好ましく、０．０２ｍｍｏｌ以上がより好ましい。上限は、１０ｍｍｏｌ以下が好ましく、１ｍｍｏｌ以下がより好ましく、０．５ｍｍｏｌ以下がさらに好ましい。従って、Ｎ－オキシル化合物の使用量は絶乾１ｇのセルロースに対して、０．０１ｍｍｏｌ以上１０ｍｍｏｌ以下が好ましく、０．０１ｍｍｏｌ以上１ｍｍｏｌ以下がより好ましく、０．０２ｍｍｏｌ以上０．５ｍｍｏｌ以下がさらに好ましい。 An N-oxyl compound refers to a compound capable of generating a nitroxy radical. Examples of nitroxy radicals include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). As the N-oxyl compound, any compound can be used as long as it promotes the target oxidation reaction.
The amount of the N-oxyl compound used is not particularly limited as long as it is a catalyst amount that can oxidize cellulose as a raw material. For example, 0.01 mmol or more is preferable and 0.02 mmol or more is more preferable with respect to 1 g of absolutely dry cellulose. The upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, and even more preferably 0.5 mmol or less. Therefore, the amount of N-oxyl compound used is preferably 0.01 mmol or more and 10 mmol or less, more preferably 0.01 mmol or more and 1 mmol or less, and further preferably 0.02 mmol or more and 0.5 mmol or less with respect to 1 g of absolutely dry cellulose.
　臭化物とは臭素を含む化合物であり、例えば、水中で解離してイオン化可能な臭化アルカリ金属、例えば臭化ナトリウム等が挙げられる。また、ヨウ化物とはヨウ素を含む化合物であり、例えば、ヨウ化アルカリ金属が挙げられる。臭化物又はヨウ化物の使用量は、酸化反応を促進できる範囲で選択すればよい。臭化物及びヨウ化物の合計量は絶乾１ｇのセルロースに対して、０．１ｍｍｏｌ以上が好ましく、０．５ｍｍｏｌ以上がより好ましい。上限は、１００ｍｍｏｌ以下が好ましく、１０ｍｍｏｌ以下がより好ましく、５ｍｍｏｌ以下がさらに好ましい。従って、臭化物及びヨウ化物の合計量は絶乾１ｇのセルロースに対して、０．１ｍｍｏｌ以上１００ｍｍｏｌ以下が好ましく、０．１ｍｍｏｌ以上１０ｍｍｏｌ以下がより好ましく、０．５ｍｍｏｌ以上５ｍｍｏｌ以下がさらに好ましい。 Bromide is a compound containing bromine, and examples thereof include alkali metal bromide that can be dissociated and ionized in water, such as sodium bromide. Further, the iodide is a compound containing iodine, and examples thereof include alkali metal iodide. What is necessary is just to select the usage-amount of a bromide or iodide in the range which can accelerate | stimulate an oxidation reaction. The total amount of bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, with respect to 1 g of absolutely dry cellulose. The upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, and even more preferably 5 mmol or less. Therefore, the total amount of bromide and iodide is preferably 0.1 mmol or more and 100 mmol or less, more preferably 0.1 mmol or more and 10 mmol or less, and further preferably 0.5 mmol or more and 5 mmol or less with respect to 1 g of absolutely dry cellulose.
　酸化剤は、特に限定されないが例えば、ハロゲン、次亜ハロゲン酸、亜ハロゲン酸、過ハロゲン酸、それらの塩、ハロゲン酸化物、過酸化物などが挙げられる。中でも、安価で環境負荷が少ないことから、次亜ハロゲン酸又はその塩が好ましく、次亜塩素酸又はその塩がより好ましく、次亜塩素酸ナトリウムがさらに好ましい。酸化剤の使用量は、絶乾１ｇのセルロースに対して、０．５ｍｍｏｌ以上が好ましく、１ｍｍｏｌ以上がより好ましく、３ｍｍｏｌ以上がさらに好ましい。上限は、５００ｍｍｏｌ以下が好ましく、５０ｍｍｏｌ以下がより好ましく、２５ｍｍｏｌ以下がさらに好ましく、１０ｍｍｏｌ以下が最も好ましい。従って、酸化剤の使用量は絶乾１ｇのセルロースに対して、０．５ｍｍｏｌ以上５００ｍｍｏｌ以下が好ましく、０．５ｍｍｏｌ以上５０ｍｍｏｌ以下がより好ましく、１ｍｍｏｌ以上２５ｍｍｏｌ以下がさらに好ましく、３ｍｍｏｌ以上１０ｍｍｏｌ以下が最も好ましい。Ｎ－オキシル化合物を用いる場合、酸化剤の使用量はＮ－オキシル化合物１ｍｏｌに対して１ｍｏｌ以上が好ましい。上限は、４０ｍｏｌ以下が好ましい。従って、酸化剤の使用量はＮ－オキシル化合物１ｍｏｌに対して１ｍｏｌ以上４０ｍｏｌ以下が好ましい。 The oxidizing agent is not particularly limited, and examples thereof include halogen, hypohalous acid, halous acid, perhalogen acid, salts thereof, halogen oxide, and peroxide. Among them, hypohalous acid or a salt thereof is preferable because it is inexpensive and has a low environmental burden, hypochlorous acid or a salt thereof is more preferable, and sodium hypochlorite is more preferable. The amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, and further preferably 3 mmol or more with respect to 1 g of absolutely dry cellulose. The upper limit is preferably 500 mmol or less, more preferably 50 mmol or less, further preferably 25 mmol or less, and most preferably 10 mmol or less. Therefore, the amount of the oxidizing agent used is preferably 0.5 mmol or more and 500 mmol or less, more preferably 0.5 mmol or more and 50 mmol or less, further preferably 1 mmol or more and 25 mmol or less, and most preferably 3 mmol or more and 10 mmol or less with respect to 1 g of absolutely dry cellulose. preferable. When an N-oxyl compound is used, the amount of the oxidizing agent used is preferably 1 mol or more with respect to 1 mol of the N-oxyl compound. The upper limit is preferably 40 mol or less. Therefore, the amount of the oxidizing agent used is preferably 1 mol or more and 40 mol or less with respect to 1 mol of the N-oxyl compound.
　酸化反応時のｐＨ、温度等の条件は特に限定されず、一般に、比較的温和な条件であっても酸化反応は効率よく進行する。反応温度は４℃以上が好ましく、１５℃以上がより好ましい。上限は４０℃以下が好ましく、３０℃以下がより好ましい。従って、温度は４℃以上４０℃以下が好ましく、１５℃以上３０℃以下、すなわち室温であってもよい。反応液のｐＨは、８以上が好ましく、１０以上がより好ましい。上限は、１２以下が好ましく、１１以下がより好ましい。従って、反応液のｐＨは、好ましくは８以上１２以下、より好ましくは１０以上１１以下程度である。通常、酸化反応の進行に伴ってセルロース中にカルボキシル基が生成するため、反応液のｐＨは低下する傾向にある。そのため、酸化反応を効率よく進行させるためには、水酸化ナトリウム水溶液などのアルカリ性溶液を添加して、反応液のｐＨを上記の範囲に維持することが好ましい。酸化の際の反応媒体は、取扱い性の容易さや、副反応が生じにくいこと等の理由から、水が好ましい。 The conditions such as pH and temperature during the oxidation reaction are not particularly limited, and generally the oxidation reaction proceeds efficiently even under relatively mild conditions. The reaction temperature is preferably 4 ° C or higher, more preferably 15 ° C or higher. The upper limit is preferably 40 ° C. or lower, and more preferably 30 ° C. or lower. Therefore, the temperature is preferably 4 ° C. or higher and 40 ° C. or lower, and may be 15 ° C. or higher and 30 ° C. or lower, that is, room temperature. The pH of the reaction solution is preferably 8 or more, and more preferably 10 or more. The upper limit is preferably 12 or less, and more preferably 11 or less. Therefore, the pH of the reaction solution is preferably 8 or more and 12 or less, more preferably 10 or more and 11 or less. Usually, a carboxyl group is generated in cellulose as the oxidation reaction proceeds, and therefore the pH of the reaction solution tends to decrease. Therefore, in order to advance the oxidation reaction efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution in the above range. The reaction medium for the oxidation is preferably water for reasons such as ease of handling and the difficulty of side reactions.
　酸化における反応時間は、酸化の進行の程度に従って適宜設定することができ、通常は０．５時間以上である。上限は通常は６時間以下、好ましくは４時間以下である。従って、酸化における反応時間は通常０．５時間以上６時間以下、例えば０．５時間以上４時間以下である。
　酸化は、２段階以上の反応に分けて実施してもよい。例えば、１段階目の反応終了後に濾別して得られた酸化セルロースを、再度、同一又は異なる反応条件で酸化させることにより、１段階目の反応で副生する食塩による反応阻害を受けることなく、効率よく酸化させることができる。 The reaction time in the oxidation can be appropriately set according to the progress of the oxidation, and is usually 0.5 hours or longer. The upper limit is usually 6 hours or less, preferably 4 hours or less. Therefore, the reaction time in oxidation is usually 0.5 hours or more and 6 hours or less, for example 0.5 hours or more and 4 hours or less.
Oxidation may be carried out in two or more stages. For example, the oxidized cellulose obtained by filtration after the completion of the first stage reaction is oxidized again under the same or different reaction conditions, thereby preventing the reaction from being inhibited by the salt produced as a by-product in the first stage reaction. Can be oxidized well.
　カルボキシル化（酸化）方法の別の例として、オゾン処理により酸化する方法が挙げられる。この酸化反応により、セルロースを構成するグルコピラノース環の少なくとも２位及び６位の水酸基が酸化されると共に、セルロース鎖の分解が起こる。オゾン処理は通常、オゾンを含む気体とセルロース原料とを接触させることにより行われる。気体中のオゾン濃度は、５０ｇ／ｍ３以上であることが好ましい。上限は、２５０ｇ／ｍ３以下であることが好ましく、２２０ｇ／ｍ３以下であることがより好ましい。従って、気体中のオゾン濃度は、５０ｇ／ｍ３以上２５０ｇ／ｍ３以下であることが好ましく、５０ｇ／ｍ３以上２２０ｇ／ｍ３以下であることがより好ましい。オゾン添加量は、セルロース原料の固形分１００重量％に対し、０．１重量％以上であることが好ましく、５重量％以上であることがより好ましい。上限は、通常３０重量％以下である。従って、オゾン添加量は、セルロース原料の固形分１００重量％に対し、０．１重量％以上３０重量％以下であることが好ましく、５重量％以上３０重量％以下であることがより好ましい。オゾン処理温度は、通常０℃以上であり、好ましくは２０℃以上である。上限は通常５０℃以下である。従って、オゾン処理温度は、通常０℃以上５０℃以下であり、２０℃以上５０℃以下であることが好ましい。オゾン処理時間は、通常は１分以上であり、好ましくは３０分以上である。上限は通常３６０分以下である。従って、オゾン処理時間は、通常は１分以上３６０分以下であり、３０分以上３６０分以下が好ましい。オゾン処理の条件が上述の範囲内であると、セルロースが過度に酸化及び分解されることを防ぐことができ、酸化セルロースの収率が良好となる。 Another example of the carboxylation (oxidation) method is a method of oxidizing by ozone treatment. By this oxidation reaction, at least the 2- and 6-position hydroxyl groups of the glucopyranose ring constituting cellulose are oxidized, and the cellulose chain is decomposed. The ozone treatment is usually performed by bringing a gas containing ozone and a cellulose raw material into contact with each other. The ozone concentration in the gas is preferably 50 g / m 3 or more. The upper limit is preferably 250 g / m 3 or less, and more preferably 220 g / m 3 or less. Therefore, the ozone concentration in the gas is preferably at most 50 g / m 3 or more 250 g / m 3, more preferably at most 50 g / m 3 or more 220 g / m 3. The amount of ozone added is preferably 0.1% by weight or more, and more preferably 5% by weight or more, based on 100% by weight of the solid content of the cellulose raw material. The upper limit is usually 30% by weight or less. Therefore, the amount of ozone added is preferably 0.1% by weight to 30% by weight and more preferably 5% by weight to 30% by weight with respect to 100% by weight of the solid content of the cellulose raw material. The ozone treatment temperature is usually 0 ° C. or higher, preferably 20 ° C. or higher. The upper limit is usually 50 ° C. or lower. Therefore, the ozone treatment temperature is usually 0 ° C. or higher and 50 ° C. or lower, and preferably 20 ° C. or higher and 50 ° C. or lower. The ozone treatment time is usually 1 minute or longer, preferably 30 minutes or longer. The upper limit is usually 360 minutes or less. Therefore, the ozone treatment time is usually from 1 minute to 360 minutes, preferably from 30 minutes to 360 minutes. When the condition of the ozone treatment is within the above range, it is possible to prevent the cellulose from being excessively oxidized and decomposed, and the yield of oxidized cellulose is improved.
　オゾン処理後に得られる結果物に対しさらに、酸化剤を用いて追酸化処理を行ってもよい。追酸化処理に用いる酸化剤は、特に限定されないが例えば、二酸化塩素、亜塩素酸ナトリウム等の塩素系化合物；酸素、過酸化水素、過硫酸、過酢酸などが挙げられる。追酸化処理の方法としては例えば、これらの酸化剤を水又はアルコール等の極性有機溶媒中に溶解して酸化剤溶液を作成し、酸化剤溶液中にセルロース原料を浸漬させる方法が挙げられる。 The resulting product obtained after the ozone treatment may be further oxidized using an oxidizing agent. The oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite; oxygen, hydrogen peroxide, persulfuric acid, peracetic acid and the like. Examples of the method for the additional oxidation treatment include a method in which these oxidizing agents are dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and the cellulose raw material is immersed in the oxidizing agent solution.
　酸化セルロースナノファイバーに含まれるカルボキシル基、カルボキシレート基、アルデヒド基の量は、酸化剤の添加量、反応時間等の酸化条件をコントロールすることで調整することができる。
　カルボキシル基量の測定方法の一例を以下に説明する。酸化セルロースの０．５重量％スラリー（水分散液）６０ｍｌを調製し、０．１Ｍ塩酸水溶液を加えてｐＨ２．５とした後、０．０５Ｎの水酸化ナトリウム水溶液を滴下してｐＨが１１になるまで電気伝導度を測定する。電気伝導度の変化が緩やかな弱酸の中和段階において消費された水酸化ナトリウム量（ａ〔ｍｌ〕）から、下式を用いてカルボキシル基量を算出することができる：
　　カルボキシル基量〔ｍｍｏｌ／ｇ酸化セルロース又はセルロースナノファイバー〕＝ａ〔ｍｌ〕×０．０５／酸化セルロース重量〔ｇ〕 The amount of the carboxyl group, carboxylate group, and aldehyde group contained in the oxidized cellulose nanofiber can be adjusted by controlling the oxidizing conditions such as the addition amount of the oxidizing agent and the reaction time.
An example of a method for measuring the amount of carboxyl groups will be described below. Prepare 60 ml of 0.5 wt% slurry (aqueous dispersion) of oxidized cellulose and add 0.1 M hydrochloric acid aqueous solution to pH 2.5, then add 0.05 N sodium hydroxide aqueous solution dropwise to adjust pH to 11. Measure the electrical conductivity until The amount of carboxyl groups can be calculated from the amount of sodium hydroxide consumed (a [ml]) in the weak acid neutralization stage where the change in electrical conductivity is gradual:
Amount of carboxyl group [mmol / g oxidized cellulose or cellulose nanofiber] = a [ml] × 0.05 / oxidized cellulose weight [g]
（２－２－２）エーテル化（カルボキシメチル化）セルロースナノファイバー
　エーテル化としては、カルボキシメチル（エーテル）化、メチル（エーテル）化、エチル（エーテル）化、シアノエチル（エーテル）化、ヒドロキシエチル（エーテル）化、ヒドロキシプロピル（エーテル）化、エチルヒドロキシエチル（エーテル）化、ヒドロキシプロピルメチル（エーテル）化などが挙げられる。この中から一例としてカルボキシメチル化の方法を以下に説明する。
　カルボキシメチル化によりセルロース原料を変性する場合、得られるカルボキシメチル化セルロース又はセルロースナノファイバー中の無水グルコース単位当たりのカルボキシメチル基置換度は、０．０１以上が好ましく、０．０５以上がより好ましく、０．１０以上であることがさらに好ましい。上限は、０．５０以下が好ましく、０．４０以下がより好ましく、０．３５以下がさらに好ましい。従って、カルボキシメチル基置換度は、０．０１以上０．５０以下が好ましく、０．０５以上０．４０以下がより好ましく、０．１０以上０．３５以下がさらに好ましい。 (2-2-2) Etherified (Carboxymethylated) Cellulose Nanofiber Etherification includes carboxymethyl (ether), methyl (ether), ethyl (ether), cyanoethyl (ether), hydroxyethyl ( Examples include ether), hydroxypropyl (ether), ethylhydroxyethyl (ether), and hydroxypropylmethyl (ether). As an example, a carboxymethylation method will be described below.
When the cellulose raw material is modified by carboxymethylation, the degree of carboxymethyl group substitution per anhydroglucose unit in the obtained carboxymethylated cellulose or cellulose nanofiber is preferably 0.01 or more, more preferably 0.05 or more, More preferably, it is 0.10 or more. The upper limit is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.35 or less. Therefore, the degree of carboxymethyl group substitution is preferably from 0.01 to 0.50, more preferably from 0.05 to 0.40, and even more preferably from 0.10 to 0.35.
　カルボキシメチル化の方法は特に限定されないが、例えば、発底原料としてのセルロース原料をマーセル化し、その後エーテル化する方法が挙げられる。カルボキシメチル化反応に用いる溶媒としては例えば、水、アルコール（例えば、低級アルコール）及びこれらの混合溶媒が挙げられる。低級アルコールとしては、例えば、メタノール、エタノール、Ｎ－プロピルアルコール、イソプロピルアルコール、Ｎ－ブタノール、イソブタノール、第３級ブタノールが挙げられる。混合溶媒における低級アルコールの混合割合は、通常は６０重量％以上９５重量％以下である。溶媒の量は、セルロース原料に対し通常は３重量倍である。上限は特に限定されないが２０重量倍である。従って、溶媒の量は３重量倍以上２０重量倍以下であることが好ましい。 The method of carboxymethylation is not particularly limited, and examples thereof include a method of mercerizing a cellulose raw material as a bottoming raw material and then etherifying. Examples of the solvent used for the carboxymethylation reaction include water, alcohols (for example, lower alcohols), and mixed solvents thereof. Examples of the lower alcohol include methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, and tertiary butanol. The mixing ratio of the lower alcohol in the mixed solvent is usually 60% by weight or more and 95% by weight or less. The amount of the solvent is usually 3 times the weight of the cellulose raw material. Although an upper limit is not specifically limited, It is 20 weight times. Therefore, the amount of the solvent is preferably 3 to 20 times by weight.
　マーセル化は通常、発底原料とマーセル化剤を混合して行う。マーセル化剤としては例えば、水酸化ナトリウム、水酸化カリウム等の水酸化アルカリ金属が挙げられる。マーセル化剤の使用量は、発底原料の無水グルコース残基当たり０．５倍モル以上が好ましく、１．０倍モル以上がより好ましく、１．５倍モル以上であることがさらに好ましい。上限は、通常２０倍モル以下であり、１０倍モル以下が好ましく、５倍モル以下がより好ましい。従って、０．５倍モル以上２０倍モル以下が好ましく、１．０倍モル以上１０倍モル以下がより好ましく、１．５倍モル以上５倍モル以下がさらに好ましい。
　マーセル化の反応温度は、通常０℃以上であり、好ましくは１０℃以上である。上限は通常７０℃以下、好ましくは６０℃以下である。従って、反応温度は、通常０℃以上７０℃以下、好ましくは１０℃以上６０℃以下である。反応時間は、通常１５分以上、好ましくは３０分以上である。上限は、通常８時間以下、好ましくは７時間以下である。従って、通常は１５分以上８時間以下、好ましくは３０分以上７時間以下である。 Mercerization is usually performed by mixing a bottoming raw material and a mercerizing agent. Examples of mercerizing agents include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of mercerizing agent used is preferably 0.5 times mol or more, more preferably 1.0 times mol or more, and further preferably 1.5 times mol or more per anhydroglucose residue of the starting material. The upper limit is usually 20 times mole or less, preferably 10 times mole or less, and more preferably 5 times mole or less. Therefore, 0.5 times mole or more and 20 times mole or less are preferable, 1.0 times mole or more and 10 times mole or less are more preferable, and 1.5 times mole or more and 5 times mole or less are more preferable.
The mercerization reaction temperature is usually 0 ° C. or higher, preferably 10 ° C. or higher. The upper limit is usually 70 ° C. or lower, preferably 60 ° C. or lower. Therefore, the reaction temperature is usually 0 ° C. or higher and 70 ° C. or lower, preferably 10 ° C. or higher and 60 ° C. or lower. The reaction time is usually 15 minutes or longer, preferably 30 minutes or longer. The upper limit is usually 8 hours or less, preferably 7 hours or less. Therefore, it is usually from 15 minutes to 8 hours, preferably from 30 minutes to 7 hours.
　エーテル化反応は、通常、カルボキシメチル化剤をマーセル化後に反応系に追加して行う。カルボキシメチル化剤としては、例えば、モノクロロ酢酸ナトリウムが挙げられる。カルボキシメチル化剤の添加量は、セルロース原料のグルコース残基当たり通常０．０５倍モル以上が好ましく、０．５倍モル以上がより好ましく、０．８倍モル以上であることがさらに好ましい。上限は、通常１０．０倍モル以下であり、５倍モル以下が好ましく、３倍モル以下がより好ましい、従って、好ましくは０．０５倍モル以上１０．０倍モル以下であり、より好ましくは０．５倍モル以上５倍モル以下であり、さらに好ましくは０．８倍モル以上３倍モル以下である。反応温度は通常３０℃以上、好ましくは４０℃以上であり、上限は通常９０℃以下、好ましくは８０℃以下である。従って反応温度は通常３０℃以上９０℃以下、好ましくは４０℃以上８０℃以下である。反応時間は、通常３０分以上であり、好ましくは１時間以上である。上限は、通常は１０時間以下、好ましくは４時間以下である。従って反応時間は、通常は３０分以上１０時間以下であり、好ましくは１時間以上４時間以下である。カルボキシメチル化反応の間必要に応じて、反応液を撹拌してもよい。 The etherification reaction is usually performed by adding a carboxymethylating agent to the reaction system after mercerization. Examples of the carboxymethylating agent include sodium monochloroacetate. The addition amount of the carboxymethylating agent is usually preferably 0.05 times mol or more, more preferably 0.5 times mol or more, and further preferably 0.8 times mol or more per glucose residue of the cellulose raw material. The upper limit is usually 10.0 times mol or less, preferably 5 times mol or less, more preferably 3 times mol or less, and thus preferably 0.05 times mol or more and 10.0 times mol or less, more preferably It is 0.5 times mole or more and 5 times mole or less, More preferably, it is 0.8 times mole or more and 3 times mole or less. The reaction temperature is usually 30 ° C. or higher, preferably 40 ° C. or higher, and the upper limit is usually 90 ° C. or lower, preferably 80 ° C. or lower. Accordingly, the reaction temperature is usually 30 ° C. or higher and 90 ° C. or lower, preferably 40 ° C. or higher and 80 ° C. or lower. The reaction time is usually 30 minutes or longer, preferably 1 hour or longer. The upper limit is usually 10 hours or less, preferably 4 hours or less. Therefore, the reaction time is usually from 30 minutes to 10 hours, preferably from 1 hour to 4 hours. The reaction solution may be stirred as necessary during the carboxymethylation reaction.
　カルボキシメチル化セルロースナノファイバーのグルコース単位当たりのカルボキシメチル置換度の測定は例えば、次の方法によって行えばよい。すなわち、１）カルボキシメチル化セルロース（絶乾）約２．０ｇを精秤して、３００ｍＬ容共栓付き三角フラスコに入れる。２）硝酸メタノール１０００ｍＬに特級濃硝酸１００ｍＬを加えた液１００ｍＬを加え、３時間振とうして、カルボキシメチルセルロース塩（カルボキシメチル化セルロース）を水素型カルボキシメチル化セルロースにする。３）水素型カルボキシメチル化セルロース（絶乾）を１．５～２．０ｇ精秤し、３００ｍＬ容共栓付き三角フラスコに入れる。４）８０％メタノール１５ｍＬで水素型カルボキシメチル化セルロースを湿潤し、０．１ＮのＮａＯＨを１００ｍＬ加え、室温で３時間振とうする。５）指示薬として、フェノールフタレインを用いて、０．１ＮのＨ２ＳＯ４で過剰のＮａＯＨを逆滴定する。６）カルボキシメチル置換度（ＤＳ）を、次式によって算出する：
　Ａ　＝［（１００×Ｆ’－（０．１ＮのＨ２ＳＯ４）（ｍＬ）×Ｆ）×０．
　　　　１］／（水素型カルボキシメチル化セルロースの絶乾質量（ｇ））
　ＤＳ＝０．１６２×Ａ／（１－０．０５８×Ａ）
　　Ａ　：水素型カルボキシメチル化セルロースの１ｇの中和に要する１Ｎ
　　　　　のＮａＯＨ量（ｍＬ）
　　Ｆ’：０．１ＮのＨ２ＳＯ４のファクター
　　Ｆ　：０．１ＮのＮａＯＨのファクター The measurement of the degree of carboxymethyl substitution per glucose unit of carboxymethylated cellulose nanofibers may be performed, for example, by the following method. That is, 1) About 2.0 g of carboxymethylated cellulose (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) Add 100 mL of a solution obtained by adding 100 mL of special grade concentrated nitric acid to 1000 mL of nitric acid methanol and shake for 3 hours to convert the carboxymethylcellulose salt (carboxymethylated cellulose) to hydrogen-type carboxymethylated cellulose. 3) Weigh accurately 1.5 to 2.0 g of hydrogen-type carboxymethylated cellulose (absolutely dry) and put into a 300 mL Erlenmeyer flask with a stopper. 4) Wet the hydrogen-type carboxymethylated cellulose with 15 mL of 80% methanol, add 100 mL of 0.1N NaOH, and shake at room temperature for 3 hours. 5) Back titrate excess NaOH with 0.1N H 2 SO 4 using phenolphthalein as indicator. 6) The degree of carboxymethyl substitution (DS) is calculated by the following formula:
A = [(100 × F ′ − (0.1N H 2 SO 4 ) (mL) × F) × 0.
1] / (absolute dry mass of hydrogen-type carboxymethylated cellulose (g))
DS = 0.162 × A / (1-0.058 × A)
A: 1N required for neutralizing 1 g of hydrogen-type carboxymethylated cellulose
NaOH amount (mL)
F ′: Factor of 0.1N H 2 SO 4 F: Factor of 0.1N NaOH
（２－２－３）カチオン化セルロースナノファイバー
　カチオン化によりセルロース原料を変性する場合、得られるカチオン化セルロースナノファイバーは、アンモニウム、ホスホニウム、スルホニウム等のカチオン、又は該カチオンを有する基を分子中に含んでいればよい。カチオン化セルロースナノファイバーは、アンモニウムを有する基を含むことが好ましく、四級アンモニウムを有する基を含むことがより好ましい。 (2-2-3) Cationized cellulose nanofiber When the cellulose raw material is modified by cationization, the resulting cationized cellulose nanofiber has a cation such as ammonium, phosphonium, sulfonium, or a group having the cation in the molecule. It only has to be included. The cationized cellulose nanofiber preferably includes a group having ammonium, and more preferably includes a group having quaternary ammonium.
　カチオン化の方法は特に限定されないが例えば、セルロース原料にカチオン化剤と触媒を水及び／又はアルコールの存在下で反応させる方法が挙げられる。カチオン化剤としては例えば、グリシジルトリメチルアンモニウムクロリド、３－クロロ－２－ヒドロキシプロピルトリアルキルアンモニウムハイドライト（例：３－クロロ－２－ヒドロキシプロピルトリメチルアンモニウムハイドライト）又はこれらのハロヒドリン型などが挙げられ、これらのいずれかを用いることで、四級アンモニウムを含む基を有するカチオン化セルロースを得ることができる。触媒としては例えば、水酸化ナトリウム、水酸化カリウムなどの水酸化アルカリ金属が挙げられる。アルコールとしては例えば、炭素数１～４のアルコールが挙げられる。カチオン化剤の量は、好ましくはセルロース原料１００重量％に対して５重量％以上であり、より好ましくは１０重量％以上である。上限は通常８００重量％以下であり、好ましくは５００重量％以下である。触媒の量は、好ましくはセルロース繊維１００重量％に対して０．５重量％以上であり、より好ましくは１重量％以上である。上限は通常７重量％以下であり、好ましくは３重量％以下である。アルコールの量は、好ましくはセルロース繊維１００重量％に対して５０重量％以上であり、より好ましくは１００重量％以上である。上限は通常５００００重量％以下であり、好ましくは５００重量％以下である。 The cationization method is not particularly limited, and examples thereof include a method of reacting a cellulose raw material with a cationizing agent and a catalyst in the presence of water and / or alcohol. Examples of the cationizing agent include glycidyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrialkylammonium hydride (eg, 3-chloro-2-hydroxypropyltrimethylammonium hydride) or a halohydrin type thereof. By using any of these, a cationized cellulose having a group containing quaternary ammonium can be obtained. Examples of the catalyst include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Examples of the alcohol include alcohols having 1 to 4 carbon atoms. The amount of the cationizing agent is preferably 5% by weight or more, more preferably 10% by weight or more with respect to 100% by weight of the cellulose raw material. The upper limit is usually 800% by weight or less, preferably 500% by weight or less. The amount of the catalyst is preferably 0.5% by weight or more, more preferably 1% by weight or more with respect to 100% by weight of the cellulose fibers. The upper limit is usually 7% by weight or less, preferably 3% by weight or less. The amount of alcohol is preferably 50% by weight or more, more preferably 100% by weight or more, based on 100% by weight of cellulose fibers. The upper limit is usually 50000% by weight or less, preferably 500% by weight or less.
　カチオン化の際の反応温度は通常１０℃以上、好ましくは３０℃以上であり、上限は通常９０℃以下、好ましくは８０℃以下である。反応時間は、通常１０分以上であり、好ましくは３０分以上である。上限は、通常は１０時間以下、好ましくは５時間以下である。カチオン化反応の間必要に応じて、反応液を撹拌してもよい。
　カチオン化セルロースのグルコース単位当たりのカチオン置換度は、カチオン化剤の添加量、水及び／又はアルコールの組成比率のコントロールによって調整することができる。カチオン置換度とは、セルロースを構成する単位構造（グルコピラノース環）あたりの導入された置換基の個数を示す。言い換えると、カチオン置換度は、「導入された置換基のモル数をグルコピラノース環の水酸基の総モル数で割った値」として定義される。純粋セルロースは単位構造（グルコピラノース環）あたり３個の置換可能な水酸基を有しているため、カチオン置換度の理論最大値は３（最小値は０）である。 The reaction temperature at the time of cationization is usually 10 ° C or higher, preferably 30 ° C or higher, and the upper limit is usually 90 ° C or lower, preferably 80 ° C or lower. The reaction time is usually 10 minutes or longer, preferably 30 minutes or longer. The upper limit is usually 10 hours or less, preferably 5 hours or less. The reaction solution may be stirred as necessary during the cationization reaction.
The degree of cation substitution per glucose unit in the cationized cellulose can be adjusted by controlling the amount of cationizing agent added and the composition ratio of water and / or alcohol. The degree of cation substitution refers to the number of substituents introduced per unit structure (glucopyranose ring) constituting cellulose. In other words, the degree of cation substitution is defined as “a value obtained by dividing the number of moles of the introduced substituent by the total number of moles of hydroxyl groups of the glucopyranose ring”. Since pure cellulose has three substitutable hydroxyl groups per unit structure (glucopyranose ring), the theoretical maximum value of the degree of cation substitution is 3 (the minimum value is 0).
　カチオン化セルロースナノファイバーのグルコース単位当たりのカチオン置換度は、０．０１以上が好ましく、０．０２以上がより好ましく、０．０３以上がさらに好ましい。上限は、０．４０以下が好ましく、０．３０以下がより好ましく、０．２０以下がさらに好ましい。従って、０．０１以上０．４０以下であることが好ましく、０．０２以上０．３０以下がより好ましく、０．０３以上０．２０以下がさらに好ましい。セルロースにカチオン置換基を導入することで、セルロース同士が電気的に反発する。このため、カチオン置換基を導入したセルロースは容易にナノ解繊することができる。グルコース単位当たりのカチオン置換度が０．０１以上であることにより、十分にナノ解繊することができる。一方、グルコース単位当たりのカチオン置換度が０．４０以下であることにより、膨潤又は溶解を抑制することができ、これにより繊維形態を維持することができ、ナノファイバーとして得られない事態を防止することができる。 The cation substitution degree per glucose unit of the cationized cellulose nanofiber is preferably 0.01 or more, more preferably 0.02 or more, and further preferably 0.03 or more. The upper limit is preferably 0.40 or less, more preferably 0.30 or less, and further preferably 0.20 or less. Therefore, it is preferably 0.01 or more and 0.40 or less, more preferably 0.02 or more and 0.30 or less, and further preferably 0.03 or more and 0.20 or less. By introducing a cationic substituent into cellulose, the celluloses repel each other electrically. For this reason, the cellulose which introduce | transduced the cation substituent can be nano-defibrated easily. When the degree of cation substitution per glucose unit is 0.01 or more, nano-defibration can be sufficiently performed. On the other hand, when the degree of cation substitution per glucose unit is 0.40 or less, swelling or dissolution can be suppressed, whereby the fiber form can be maintained, and a situation where nanofibers cannot be obtained is prevented. be able to.
　グルコース単位当たりのカチオン置換度の測定方法の一例を以下に説明する。試料（カチオン化セルロース）を乾燥させた後に、全窒素分析計ＴＮ－１０（三菱化学株式会社製）で窒素含有量を測定し、次式によりカチオン置換度を算出する。ここでいうカチオン置換度とは、無水グルコース単位１モル当たりの置換基のモル数の平均値である。
　カチオン置換度＝（１６２×Ｎ）／（１－１５１．６×Ｎ）
　　Ｎ　：窒素含有量 An example of a method for measuring the degree of cation substitution per glucose unit will be described below. After drying the sample (cationized cellulose), the nitrogen content is measured with a total nitrogen analyzer TN-10 (manufactured by Mitsubishi Chemical Corporation), and the degree of cation substitution is calculated according to the following formula. The cation substitution degree here is an average value of the number of moles of substituents per mole of anhydroglucose unit.
Degree of cation substitution = (162 × N) / (1-151.6 × N)
N: Nitrogen content
（２－２－４）エステル化セルロースナノファイバー
　エステル化の方法は特に限定されないが、例えば、セルロース原料に対し下記化合物Ａを反応させる方法が挙げられる。セルロース原料に対し化合物Ａを反応させる方法としては例えば、セルロース原料に化合物Ａの粉末又は水溶液を混合する方法、セルロース原料のスラリーに化合物Ａの水溶液を添加する方法等が挙げられる。これらのうち、反応の均一性が高まり、且つエステル化効率が高くなることから、セルロース原料又はそのスラリーに化合物Ａの水溶液を混合する方法が好ましい。 (2-2-4) Esterified Cellulose Nanofiber The method of esterification is not particularly limited, and examples thereof include a method of reacting the following compound A with a cellulose raw material. Examples of the method of reacting compound A with a cellulose raw material include a method of mixing a powder or an aqueous solution of compound A with a cellulose raw material, a method of adding an aqueous solution of compound A to a slurry of a cellulose raw material, and the like. Among these, since the uniformity of the reaction is enhanced and the esterification efficiency is increased, a method of mixing an aqueous solution of Compound A into a cellulose raw material or a slurry thereof is preferable.
　化合物Ａとしては、例えば、リン酸、ポリリン酸、亜リン酸、ホスホン酸、ポリホスホン酸、これらのエステル等が挙げられる。化合物Ａは、塩の形態でもよい。上記の中でも、低コストであり、扱いやすく、またパルプ繊維のセルロースにリン酸基を導入して、解繊効率の向上が図れるなどの理由から、リン酸系化合物が好ましい。リン酸系化合物は、リン酸基を有する化合物であればよく、例えば、リン酸、リン酸二水素ナトリウム、リン酸水素二ナトリウム、リン酸三ナトリウム、ピロリン酸ナトリウム、メタリン酸ナトリウム、リン酸二水素カリウム、リン酸水素二カリウム、リン酸三カリウム、ピロリン酸カリウム、メタリン酸カリウム、リン酸二水素アンモニウム、リン酸水素二アンモニウム、リン酸三アンモニウム、ピロリン酸アンモニウム、メタリン酸アンモニウム等が挙げられる。用いられるリン酸系化合物は、１種、あるいは２種以上の組み合わせでもよい。これらのうち、リン酸基導入の効率が高く、下記解繊工程で解繊しやすく、かつ工業的に適用しやすい観点から、リン酸、リン酸のナトリウム塩、リン酸のカリウム塩、リン酸のアンモニウム塩が好ましく、リン酸二水素ナトリウム、リン酸水素二ナトリウムがより好ましい。また、反応の均一性が高まり、且つリン酸基導入の効率が高くなることから、エステル化においてはリン酸系化合物の水溶液を用いることが好ましい。リン酸系化合物の水溶液のｐＨは、リン酸基導入の効率が高くなることから、７以下が好ましく、パルプ繊維の加水分解を抑える観点から、ｐＨ３以上がより好ましい。 Examples of compound A include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, and esters thereof. Compound A may be in the form of a salt. Among them, a phosphoric acid compound is preferable because it is low in cost and easy to handle, and a phosphoric acid group can be introduced into cellulose of pulp fiber to improve the fibrillation efficiency. The phosphate compound may be any compound having a phosphate group. For example, phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, diphosphate Examples include potassium hydrogen, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium metaphosphate. . The phosphoric acid compound used may be one type or a combination of two or more types. Among these, phosphoric acid, phosphoric acid sodium salt, phosphoric acid potassium salt, phosphoric acid, from the viewpoint that phosphoric acid group introduction efficiency is high, is easy to be defibrated in the following defibrating process, and is industrially applicable. Are preferred, and sodium dihydrogen phosphate and disodium hydrogen phosphate are more preferred. In addition, it is preferable to use an aqueous solution of a phosphoric acid compound in the esterification because the uniformity of the reaction is enhanced and the efficiency of introduction of phosphoric acid groups is increased. The pH of the aqueous solution of the phosphoric acid compound is preferably 7 or less from the viewpoint of increasing the efficiency of introducing phosphate groups, and more preferably pH 3 or more from the viewpoint of suppressing hydrolysis of the pulp fiber.
　エステル化の方法としては例えば、以下の方法が挙げられる。セルロース原料の懸濁液（例えば、固形分濃度０．１～１０重量％）に化合物Ａを撹拌しながら添加し、セルロースにリン酸基を導入する。セルロース原料を１００重量部とした際に、化合物Ａがリン酸系化合物の場合、化合物Ａの添加量はリン元素量として、０．２重量部以上が好ましく、１重量部以上がより好ましい。これにより、微細繊維状セルロースの収率をより向上させることができる。上限は、５００重量部以下が好ましく、４００重量部以下がより好ましい。これにより、化合物Ａの使用量に見合った収率を効率よく得ることができる。従って、０．２重量部以上５００重量部以下が好ましく、１重量部以上４００重量部以下がより好ましい。 Examples of the esterification method include the following methods. Compound A is added to a suspension of cellulose raw material (for example, solid content concentration of 0.1 to 10% by weight) with stirring to introduce phosphate groups into the cellulose. When the cellulose raw material is 100 parts by weight, when compound A is a phosphoric acid compound, the amount of compound A added is preferably 0.2 parts by weight or more, more preferably 1 part by weight or more, as the amount of phosphorus element. Thereby, the yield of fine fibrous cellulose can be improved more. The upper limit is preferably 500 parts by weight or less, and more preferably 400 parts by weight or less. Thereby, the yield corresponding to the usage-amount of the compound A can be obtained efficiently. Therefore, it is preferably 0.2 parts by weight or more and 500 parts by weight or less, and more preferably 1 part by weight or more and 400 parts by weight or less.
　セルロース原料に対し化合物Ａを反応させる際、さらに下記化合物Ｂを反応系に加えてもよい。化合物Ｂを反応系に加える方法としては例えば、セルロース原料のスラリー、化合物Ａの水溶液、又はセルロース原料と化合物Ａのスラリーに、添加する方法が挙げられる。 When the compound A is reacted with the cellulose raw material, the following compound B may be further added to the reaction system. Examples of the method of adding Compound B to the reaction system include a method of adding to a slurry of cellulose raw material, an aqueous solution of Compound A, or a slurry of cellulose raw material and Compound A.
　化合物Ｂは、塩基性を示す窒素含有化合物である。「塩基性を示す」とは通常、フェノールフタレイン指示薬の存在下で化合物Ｂの水溶液が桃～赤色を呈すること、または化合物Ｂの水溶液のｐＨが７より大きいことを意味する。塩基性を示す窒素含有化合物は、本発明の効果を奏する限り特に限定されないが、アミノ基を有する化合物が好ましい。例えば、尿素、メチルアミン、エチルアミン、トリメチルアミン、トリエチルアミン、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、ピリジン、エチレンジアミン、ヘキサメチレンジアミンなどが挙げられる。この中でも低コストで扱いやすい点で、尿素が好ましい。化合物Ｂの添加量は、セルロース原料を１００重量部とした際に、２重量部以上１０００重量部以下が好ましく、１００重量部以上７００重量部以下がより好ましい。反応温度は０℃以上９５℃以下が好ましく、３０℃以上９０℃以下がより好ましい。反応時間は特に限定されないが、通常１分以上６００分以下程度であり、３０分以上４８０分以下が好ましい。エステル化反応の条件がこれらのいずれかの範囲内であると、セルロースが過度にエステル化されて溶解しやすくなることを防ぐことができ、リン酸エステル化セルロースの収率を向上させることができる。 Compound B is a nitrogen-containing compound that exhibits basicity. “Show basic” usually means that the aqueous solution of Compound B is pink to red in the presence of a phenolphthalein indicator, or the pH of the aqueous solution of Compound B is greater than 7. The nitrogen-containing compound showing basicity is not particularly limited as long as the effects of the present invention are exhibited, but a compound having an amino group is preferable. For example, urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like can be mentioned. Of these, urea is preferable because it is easy to handle at low cost. The amount of Compound B added is preferably 2 parts by weight or more and 1000 parts by weight or less, and more preferably 100 parts by weight or more and 700 parts by weight or less when the cellulose raw material is 100 parts by weight. The reaction temperature is preferably 0 ° C. or higher and 95 ° C. or lower, and more preferably 30 ° C. or higher and 90 ° C. or lower. Although reaction time is not specifically limited, Usually, it is about 1 minute or more and 600 minutes or less, and 30 minutes or more and 480 minutes or less are preferable. If the conditions for the esterification reaction are in any of these ranges, it is possible to prevent cellulose from being excessively esterified and easily dissolved, and to improve the yield of phosphorylated esterified cellulose. .
　セルロース原料に化合物Ａを反応させた後、通常はエステル化セルロース懸濁液が得られる。エステル化セルロース懸濁液は必要に応じて脱水され、脱水後には加熱処理を行うことが好ましい。これにより、セルロース原料の加水分解を抑えることができる。加熱温度は、１００℃以上１７０℃以下が好ましく、加熱処理の際に水が含まれている間は１３０℃以下（さらに好ましくは１１０℃以下）で加熱し、水を除いた後１００℃以上１７０℃以下で加熱処理することがより好ましい。 After reacting compound A with the cellulose raw material, an esterified cellulose suspension is usually obtained. The esterified cellulose suspension is dehydrated as necessary, and is preferably subjected to heat treatment after dehydration. Thereby, hydrolysis of a cellulose raw material can be suppressed. The heating temperature is preferably 100 ° C. or more and 170 ° C. or less, and is heated at 130 ° C. or less (more preferably 110 ° C. or less) while water is contained in the heat treatment, and after removing water, 100 ° C. or more and 170 ° C. It is more preferable to perform the heat treatment at a temperature not higher than ° C.
　リン酸エステル化セルロースにおいては、セルロース原料にリン酸基置換基が導入されており、セルロース同士が電気的に反発する。そのため、リン酸エステル化セルロースは容易にナノ解繊することができる。リン酸エステル化セルロースのグルコース単位当たりのリン酸基置換度は０．００１以上が好ましい。これにより、十分な解繊（例えばナノ解繊）が実施できる。上限は、０．４０が好ましい。これにより、リン酸エステル化セルロースの膨潤又は溶解を防止し、ナノファイバーが得られない事態を防止することができる。従って、０．００１以上０．４０以下であることが好ましい。リン酸エステル化セルロースは、煮沸後冷水で洗浄する等の洗浄処理がなされることが好ましい。これにより解繊を効率よく行うことができる。 In phosphate esterified cellulose, a phosphate group substituent is introduced into the cellulose raw material, and the cellulose repels electrically. Therefore, phosphorylated esterified cellulose can be easily nano-defibrated. The degree of phosphate group substitution per glucose unit in the phosphate esterified cellulose is preferably 0.001 or more. Thereby, sufficient defibration (for example, nano defibration) can be implemented. The upper limit is preferably 0.40. Thereby, swelling or melt | dissolution of phosphate esterified cellulose can be prevented, and the situation where a nanofiber cannot be obtained can be prevented. Therefore, it is preferable that it is 0.001 or more and 0.40 or less. The phosphorylated cellulose is preferably subjected to a washing treatment such as washing with cold water after boiling. Thereby, defibration can be performed efficiently.
（２－３）解繊
　セルロース原料の解繊は、セルロース原料に変性処理を施す前に行ってもよいし、後に行ってもよい。また、解繊は、一度に行ってもよいし、複数回行ってもよい。複数回の場合それぞれの解繊の時期はいつでもよい。
　解繊に用いる装置は特に限定されないが、例えば、高速回転式、コロイドミル式、高圧式、ロールミル式、超音波式などのタイプの装置が挙げられ、高圧又は超高圧ホモジナイザーが好ましく、湿式の高圧又は超高圧ホモジナイザーがより好ましい。装置は、セルロース原料又は変性セルロース（通常は分散液）に強力なせん断力を印加できるものが好ましい。装置が印加できる圧力は、５０ＭＰａ以上が好ましく、より好ましくは１００ＭＰａ以上であり、さらに好ましくは１４０ＭＰａ以上である。装置は、セルロース原料又は変性セルロース（通常は分散液）に上記圧力を印加することができかつ強力なせん断力を印加できる、湿式の高圧又は超高圧ホモジナイザーが好ましい。これにより、解繊を効率的に行うことができる。 (2-3) Defibration The cellulose raw material may be defibrated before or after the cellulose raw material is modified. Moreover, defibration may be performed at once or a plurality of times. In the case of multiple times, each defibration period may be any time.
The apparatus used for defibration is not particularly limited, and examples thereof include high-speed rotating type, colloid mill type, high-pressure type, roll mill type, ultrasonic type and the like, and high-pressure or ultra-high-pressure homogenizers are preferable, and wet high pressure Or an ultra high pressure homogenizer is more preferable. The apparatus is preferably capable of applying a strong shearing force to the cellulose raw material or modified cellulose (usually a dispersion). The pressure that can be applied by the apparatus is preferably 50 MPa or more, more preferably 100 MPa or more, and still more preferably 140 MPa or more. The apparatus is preferably a wet high-pressure or ultrahigh-pressure homogenizer capable of applying the above pressure to a cellulose raw material or modified cellulose (usually a dispersion) and applying a strong shearing force. Thereby, defibration can be performed efficiently.
　解繊をセルロース原料の分散体に対して行う場合、分散体中のセルロース原料の固形分濃度は、通常は０．１重量％以上、好ましくは０．２重量％以上、より好ましくは０．３重量％以上である。これにより、セルロース繊維原料の量に対する液量が適量となり効率的である。上限は通常１０重量％以下、好ましくは６重量％以下である。これにより流動性を保持することができる。
　解繊（好ましくは高圧ホモジナイザーでの解繊）、又は必要に応じて解繊前に行う分散処理に先立ち、必要に応じて予備処理を行ってもよい。予備処理は、高速せん断ミキサーなどの混合、撹拌、乳化、分散装置を用いて行えばよい。 When defibration is performed on a dispersion of cellulose raw material, the solid content concentration of the cellulose raw material in the dispersion is usually 0.1% by weight or more, preferably 0.2% by weight or more, more preferably 0.3%. % By weight or more. Thereby, the liquid quantity with respect to the quantity of a cellulose fiber raw material becomes an appropriate quantity, and is efficient. The upper limit is usually 10% by weight or less, preferably 6% by weight or less. Thereby, fluidity | liquidity can be hold | maintained.
Prior to defibration (preferably defibration with a high-pressure homogenizer) or dispersion treatment performed before defibration as necessary, pretreatment may be performed as necessary. The pretreatment may be performed using a mixing, stirring, emulsifying, and dispersing device such as a high-speed shear mixer.
（２－４）セルロースナノファイバー
　本発明において、セルロースナノファイバーは、分散液のまま用いてもよいが、必要に応じ乾燥処理を行うことにより、溶媒を一部あるいは完全に除去して、湿潤固形物あるいは乾燥固形物として用いてもよい。ここで湿潤固形物とは、分散液と乾燥固形物との中間の態様の固形物である。
　乾燥処理を行う際には、再分散性を向上させるために、予めセルロースナノファイバーの分散液に水溶性高分子を混合させた上で乾燥処理を行ってもよい。水溶性高分子としては例えば、セルロース誘導体（カルボキシメチルセルロース及びその塩、メチルセルロース、ヒドロキシプロピルセルロース、エチルセルロース）、キサンタンガム、キシログルカン、デキストリン、デキストラン、カラギーナン、ローカストビーンガム、アルギン酸、アルギン酸塩、プルラン、澱粉、かたくり粉、クズ粉、陽性澱粉、燐酸化澱粉、コーンスターチ、アラビアガム、ローカストビーンガム、ジェランガム、ゲランガム、ポリデキストロース、ペクチン、キチン、水溶性キチン、キトサン、カゼイン、アルブミン、大豆蛋白溶解物、ペプトン、ポリビニルアルコール、ポリアクリルアミド、ポリアクリル酸ソーダ、ポリビニルピロリドン、ポリ酢酸ビニル、ポリアミノ酸、ポリ乳酸、ポリリンゴ酸、ポリグリセリン、ラテックス、ロジン系サイズ剤、石油樹脂系サイズ剤、尿素樹脂、メラミン樹脂、エポキシ樹脂、ポリアミド樹脂、ポリアミド・ポリアミン樹脂、ポリエチレンイミン、ポリアミン、植物ガム、ポリエチレンオキサイド、親水性架橋ポリマー、ポリアクリル酸塩、でんぷんポリアクリル酸共重合体、タマリンドガム、ジェランガム、ペクチン、グァーガム及びコロイダルシリカ並びにそれら１つ以上の混合物が挙げられる。この中でも、カルボキシメチルセルロース及びその塩を用いることが相溶性の点から好ましい。 (2-4) Cellulose nanofibers In the present invention, cellulose nanofibers may be used in the form of a dispersion, but if necessary, a drying process is carried out to partially or completely remove the solvent, thereby obtaining a wet solid. You may use as a thing or a dry solid. Here, the wet solid is a solid in an intermediate state between the dispersion and the dry solid.
When performing the drying treatment, in order to improve the redispersibility, the drying treatment may be performed after mixing the water-soluble polymer in the cellulose nanofiber dispersion in advance. Examples of water-soluble polymers include cellulose derivatives (carboxymethyl cellulose and salts thereof, methyl cellulose, hydroxypropyl cellulose, ethyl cellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, starch, Snack flour, scrap flour, positive starch, phosphorylated starch, corn starch, gum arabic, locust bean gum, gellan gum, gellan gum, polydextrose, pectin, chitin, water-soluble chitin, chitosan, casein, albumin, soy protein lysate, peptone, polyvinyl Alcohol, polyacrylamide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyamino acid, polylactic acid, polymalic acid, polyg Serine, latex, rosin sizing agent, petroleum resin sizing agent, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide / polyamine resin, polyethyleneimine, polyamine, plant gum, polyethylene oxide, hydrophilic cross-linked polymer, polyacrylic Acid salts, starch polyacrylic acid copolymers, tamarind gum, gellan gum, pectin, guar gum and colloidal silica and mixtures of one or more thereof. Among these, it is preferable from a compatible point to use carboxymethylcellulose and its salt.
　セルロースナノファイバーの乾燥固形物及び湿潤固形物は、セルロースナノファイバーの分散液又はセルロースナノファイバーと水溶性高分子の混合液を乾燥して調製すればよい。乾燥方法は特に限定されないが、例えば、スプレードライ、圧搾、風乾、熱風乾燥、及び真空乾燥が挙げられる。乾燥装置としては例えば、連続式のトンネル乾燥装置、バンド乾燥装置、縦型乾燥装置、垂直ターボ乾燥装置、多重段円板乾燥装置、通気乾燥装置、回転乾燥装置、気流乾燥装置、スプレードライヤ乾燥装置、噴霧乾燥装置、円筒乾燥装置、ドラム乾燥装置、スクリューコンベア乾燥装置、加熱管付回転乾燥装置、振動輸送乾燥装置等、回分式の箱型乾燥装置、真空箱型乾燥装置、及び撹拌乾燥装置等が挙げられる。これらの乾燥装置は、単独で用いてもよいし、２つ以上組み合わせて用いてもよい。乾燥装置は、ドラム乾燥装置が好ましい。これにより、均一に被乾燥物に熱エネルギーを直接供給することができるので、エネルギー効率を高めることができる。また、必要以上に熱を加えずに直ちに被乾燥物を回収することができる。 The dry solid and wet solid of cellulose nanofibers may be prepared by drying a dispersion of cellulose nanofibers or a mixture of cellulose nanofibers and a water-soluble polymer. Although a drying method is not specifically limited, For example, spray drying, pressing, air drying, hot air drying, and vacuum drying are mentioned. Examples of the drying device include a continuous tunnel drying device, a band drying device, a vertical drying device, a vertical turbo drying device, a multi-stage disk drying device, an aeration drying device, a rotary drying device, an air flow drying device, and a spray dryer drying device. , Spray dryers, cylindrical dryers, drum dryers, screw conveyor dryers, rotary dryers with heating tubes, vibration transport dryers, batch-type box dryers, vacuum box dryers, stirring dryers, etc. Is mentioned. These drying apparatuses may be used alone or in combination of two or more. The drying device is preferably a drum drying device. Thereby, since heat energy can be directly supplied to a to-be-dried object uniformly, energy efficiency can be improved. In addition, the material to be dried can be recovered immediately without applying more heat than necessary.
　本発明で使用されるセルロースナノファイバーは、流動性とガスバリア性に優れるので、基紙に含浸または塗工することにより、空気遮蔽性を高めることができる。 Since the cellulose nanofibers used in the present invention are excellent in fluidity and gas barrier properties, the air shielding property can be enhanced by impregnating or coating the base paper.
　セルロースナノファイバーの好ましい塗工量は、片面当たりの固形分塗工量として０．２ｇ／ｍ２以上５．０ｇ／ｍ２以下であり、好ましくは０．５ｇ／ｍ２以上３．０ｇ／ｍ２以下である。セルロースナノファイバーの塗工量が０．２ｇ／ｍ２未満では透気抵抗度の向上が少なく、空気遮蔽性が不足する。塗工量が５．０ｇ／ｍ２を越えると透湿性が低下して好ましくない。 Preferred coating weight of the cellulose nanofiber is a 0.2 g / m 2 or more 5.0 g / m 2 or less as a solid coating amount per one surface, preferably 0.5 g / m 2 or more 3.0 g / m 2 or less. When the coating amount of the cellulose nanofiber is less than 0.2 g / m 2 , the improvement of the air resistance is small and the air shielding property is insufficient. When the coating amount exceeds 5.0 g / m 2 , the moisture permeability decreases, which is not preferable.
（３）吸湿剤
　吸湿剤は、塩化リチウム、乳酸ナトリウムのようなアルカリ金属塩、塩化カルシウム、塩化マグネシウムなどのアルカリ土類金属塩、リン酸アンモニウム、スルファミン酸アンモニウムなどのアンモニウム塩、スルファミン酸グアニジンや塩酸グアニジンなどのグアニジン塩などを使用することができ、特に吸湿性に優れ安価な塩化カルシウムが好適に使用できる。これらの化合物は単独でも２種類以上を混合してもよい。また、吸湿剤のうち難燃剤として使用できるものは、基紙に難燃性を付与するために配合することもできる。 (3) Hygroscopic agent Hygroscopic agents include alkali metal salts such as lithium chloride and sodium lactate, alkaline earth metal salts such as calcium chloride and magnesium chloride, ammonium salts such as ammonium phosphate and ammonium sulfamate, guanidine sulfamate, A guanidine salt such as guanidine hydrochloride can be used, and particularly, calcium chloride which is excellent in hygroscopicity and inexpensive can be preferably used. These compounds may be used alone or in combination of two or more. Moreover, what can be used as a flame retardant among hygroscopic agents can also be mix | blended in order to provide a base paper with a flame retardance.
　吸湿剤の好ましい塗工量は、０．５ｇ／ｍ２以上２０ｇ／ｍ２以下であり、好ましくは１．０ｇ／ｍ２以上１５ｇ／ｍ２以下である。吸湿剤の塗工量が０．５ｇ／ｍ２未満では透湿性が不足する。また、塗工量が２０ｇ／ｍ２を越えると吸湿量が過多となり高温高湿度の環境では結露や吸湿剤の流れ出しなどが起こる危険性があり、好ましくない。吸湿剤は上記塗工量の範囲内であれば、基紙全体に含浸しても良く、片面または両面に塗工しても良い。 A preferable coating amount of the hygroscopic agent is 0.5 g / m 2 or more and 20 g / m 2 or less, preferably 1.0 g / m 2 or more and 15 g / m 2 or less. The coating amount of the moisture absorbent is insufficient moisture permeability is less than 0.5 g / m 2. On the other hand, if the coating amount exceeds 20 g / m 2 , the moisture absorption amount is excessive, and there is a risk that condensation or a hygroscopic agent may flow out in a high temperature and high humidity environment. The hygroscopic agent may be impregnated on the entire base paper, or may be applied on one side or both sides, as long as it is within the above coating amount range.
（４）全熱交換素子用紙
　本発明の全熱交換用素子用紙は、セルロースナノファイバーを含有する薬液と吸湿剤を含有する薬液とを、製紙用繊維からなる基紙に含浸または塗工することにより製造することができる。
　セルロースナノファイバーを含有する薬液と吸湿剤を含有する薬液とは、同一の薬液とすることが、各成分の塗工量を正確に見積もることができるため好ましい。セルロースナノファイバーと吸湿剤とを含有する薬液は、セルロースナノファイバーの分散液に、吸湿剤を添加することにより得られる。セルロースナノファイバー分散液に添加する吸湿剤の割合は、固形分質量部でセルロースナノファイバーの１質量部に対し吸湿剤を２質量部以上３０質量部以下、好ましくは５質量部以上２０質量部以下配合する。吸湿剤の配合が２質量部未満では十分な透湿性が得られない。また、吸湿剤の配合割合が３０質量部を越えると透気抵抗度が不足して好ましくない。 (4) Total heat exchange element paper The total heat exchange element paper of the present invention is obtained by impregnating or coating a base paper composed of papermaking fibers with a chemical solution containing cellulose nanofibers and a chemical solution containing a hygroscopic agent. Can be manufactured.
The chemical solution containing cellulose nanofibers and the chemical solution containing a hygroscopic agent are preferably the same chemical solution because the coating amount of each component can be accurately estimated. A chemical solution containing cellulose nanofibers and a hygroscopic agent can be obtained by adding a hygroscopic agent to a dispersion of cellulose nanofibers. The ratio of the hygroscopic agent added to the cellulose nanofiber dispersion is 2 parts by mass or more and 30 parts by mass or less, preferably 5 parts by mass or more and 20 parts by mass or less of the hygroscopic agent with respect to 1 part by mass of the cellulose nanofibers in terms of solid content. Blend. If the amount of the hygroscopic agent is less than 2 parts by mass, sufficient moisture permeability cannot be obtained. Moreover, if the mixing ratio of the hygroscopic agent exceeds 30 parts by mass, the air resistance is insufficient, which is not preferable.
　本発明の薬液には、必要に応じて、耐水化剤、難燃剤、防錆剤、抗菌剤、制菌剤、ブロッキング防止剤等の通常使用される各種機能性助剤を添加しても良い。また、薬液を基紙に塗工する場合は、少なくとも片面に塗布するが、両面に塗布する際は両面とも同じ薬液でも良く、各面で配合や組成の異なる薬液を用いても良い。 If necessary, the chemical solution of the present invention may contain various commonly used functional auxiliaries such as water-resistant agents, flame retardants, rust inhibitors, antibacterial agents, antibacterial agents, and antiblocking agents. . Moreover, when applying a chemical | medical solution to a base paper, although apply | coating to at least one side, when apply | coating to both surfaces, the same chemical | medical solution may be used for both surfaces, and the chemical | medical solution from which a mixing | blending and a composition differ on each surface may be used.
　本発明の全熱交換素子用紙は、セルロースナノファイバーを塗布することにより、優れた透気抵抗度を発揮することができる。水溶性高分子物質は、ブロッキングが発生しない範囲で添加することが可能であるが、その量は２．０ｇ／ｍ２未満であることが好ましく、０．５ｇ／ｍ２未満であることがさらに好ましい。上記水溶性高分子物質とは、ポリビニルアルコール、澱粉、澱粉誘導体、ポリエチレンオキサイド、アルギン酸塩、カルボキシメチルセルロース塩、メチルセルロース、ヒドロキシエチルセルロース等が挙げられる。 The total heat exchange element paper of the present invention can exhibit excellent air resistance by applying cellulose nanofibers. The water-soluble polymer substance can be added as long as blocking does not occur, but the amount is preferably less than 2.0 g / m 2 and more preferably less than 0.5 g / m 2. preferable. Examples of the water-soluble polymer substance include polyvinyl alcohol, starch, starch derivatives, polyethylene oxide, alginate, carboxymethylcellulose salt, methylcellulose, and hydroxyethylcellulose.
　上記のように調製されたセルロースナノファイバーを含有する薬液を基紙に塗工する方法としては、ロッドコーター、ダイコーター、カーテンコーター、２ロールサイズプレス、ロッドメタリングサイズプレス、ゲートロールコーター、ブレードコーター等の塗工機によって塗布する方法や、含浸する方法を挙げることができる。 As a method for coating a base paper with a chemical solution containing cellulose nanofibers prepared as described above, a rod coater, a die coater, a curtain coater, a 2 roll size press, a rod metalling size press, a gate roll coater, a blade The method of apply | coating with coating machines, such as a coater, and the method of impregnation can be mentioned.
　湿潤塗工層を乾燥させる方法としては、特に制限はなく、例えば蒸気加熱シリンダー、熱風エアドライヤー、ガスヒータードライヤー、電気ヒータードライヤー、赤外線ヒータードライヤー等各種の方法を単独もしくは併用して用いることができる。 The method for drying the wet coating layer is not particularly limited, and various methods such as a steam heating cylinder, a hot air air dryer, a gas heater dryer, an electric heater dryer, and an infrared heater dryer can be used alone or in combination. .
　得られた塗工紙は、必要に応じて、スーパーカレンダー、熱圧ロール等でカレンダー処理を施してもよい。カレンダー処理を施すことによって、厚さが減少して厚さ方向の熱伝導性が向上し、高密度化することによって透気抵抗度が高まり空気遮蔽性が向上する。 The obtained coated paper may be calendered with a super calender, a hot-press roll or the like, if necessary. By applying the calendar treatment, the thickness is reduced and the thermal conductivity in the thickness direction is improved. By increasing the density, the air resistance is increased and the air shielding property is improved.
　かくして製紙用繊維、吸湿剤、セルロースナノファイバーを含有する用紙が得られるが、該用紙は空気遮蔽性と透湿性を兼備し、全熱交換素子用紙として好適に使用できる。 Thus, a paper containing papermaking fibers, a hygroscopic agent, and cellulose nanofibers can be obtained. The paper has both air shielding properties and moisture permeability and can be suitably used as a total heat exchange element paper.
　全熱交換素子用紙の坪量は１０ｇ／ｍ２以上７０ｇ／ｍ２以下が好ましく、さらに好ましくは１５ｇ／ｍ２以上４０ｇ／ｍ２以下であり、最も好ましくは２０ｇ／ｍ２以上３５ｇ／ｍ２以下である。坪量が１０ｇ／ｍ２未満では強度が著しく低下して全熱交換素子へ加工する際の作業性が低下する。坪量が７０ｇ／ｍ２を越えると厚さ方向の全熱交換効率が低下して好ましくない。 The basis weight of the total heat exchange element paper is preferably 10 g / m 2 or more and 70 g / m 2 or less, more preferably 15 g / m 2 or more and 40 g / m 2 or less, and most preferably 20 g / m 2 or more and 35 g / m 2. It is as follows. When the basis weight is less than 10 g / m 2 , the strength is remarkably lowered, and workability when processing into a total heat exchange element is lowered. Basis weight unfavorably lowered total heat exchange efficiency in the thickness direction exceeds 70 g / m 2.
　全熱交換素子用紙の厚さは８μｍ以上８０μｍ以下が好ましく、この範囲内では薄いほうが全熱交換効率が高くなる傾向が見られるため、より好ましい。厚さが８μｍ未満では強度が著しく低下して全熱交換素子へ加工する際の作業性が低下する。また、厚さが８０μｍを越えると厚さ方向の全熱交換効率が低下して好ましくない。 The thickness of the total heat exchange element paper is preferably 8 μm or more and 80 μm or less, and a thinner one in this range is more preferable because the total heat exchange efficiency tends to increase. When the thickness is less than 8 μm, the strength is remarkably lowered, and workability when processing into a total heat exchange element is lowered. On the other hand, if the thickness exceeds 80 μm, the total heat exchange efficiency in the thickness direction is lowered, which is not preferable.
　全熱交換素子用紙の透気抵抗度は７００秒以上とすることが好ましい。透気抵抗度が７００秒未満では基紙の透気抵抗度と大差がなく、セルロースナノファイバーを塗工する意味がない。熱交換換気装置に使用されている熱交換素子用紙の透気抵抗度が高くなると新鮮な給気と汚れた排気の間で空気が混合し難くなり、特に炭酸ガス移行率が低下するため、給気と排気を分離する空気遮蔽性が向上する。特許文献３には、透気抵抗度が２００秒以上のとき炭酸ガス移行率は５％以下になり、透気抵抗度が５０００秒以上のとき炭酸ガス移行率は１％以下に抑えることができることが開示されており、特許文献５では透気抵抗度が５００秒以上であれば、全熱交換素子用紙として使用することが可能であるとされている。 The air resistance of the total heat exchange element paper is preferably 700 seconds or more. If the air resistance is less than 700 seconds, there is no significant difference from the air resistance of the base paper, and there is no point in applying cellulose nanofibers. If the air resistance of the heat exchange element paper used in the heat exchange ventilator increases, it becomes difficult to mix air between fresh air supply and dirty exhaust air, and especially the carbon dioxide gas transfer rate decreases. The air shielding property that separates air and exhaust is improved. Patent Document 3 states that when the air permeability resistance is 200 seconds or more, the carbon dioxide gas migration rate is 5% or less, and when the air permeability resistance is 5000 seconds or more, the carbon dioxide gas migration rate can be suppressed to 1% or less. According to Patent Document 5, if the air permeability resistance is 500 seconds or more, it can be used as a total heat exchange element sheet.
　全熱交換素子用紙の透湿度は８００ｇ／ｍ２・２４ｈｒ以上が好ましく、さらに好ましくは１０００ｇ／ｍ２・２４ｈｒ以上である。透湿度は全熱交換素子用紙の潜熱交換効率の指標として有効であり、透湿度が高い方が潜熱交換効率は高くなり、一方、透湿度が８００ｇ／ｍ２・２４ｈｒ未満では必要とされる潜熱交換効率が得られない。 The moisture permeability of the total heat exchange element paper is preferably 800 g / m 2 · 24 hr or more, more preferably 1000 g / m 2 · 24 hr or more. The moisture permeability is effective as an index of the latent heat exchange efficiency of the total heat exchange element paper. The higher the moisture permeability, the higher the latent heat exchange efficiency. On the other hand, the latent heat required when the moisture permeability is less than 800 g / m 2 · 24 hr. Exchange efficiency cannot be obtained.
　以下実施例により本発明をさらに詳しく説明する。本発明における各特性の定義および測定方法は以下のとおりである。 Hereinafter, the present invention will be described in more detail with reference to examples. The definition and measuring method of each characteristic in the present invention are as follows.
［測定方法］
（１）坪量
　２５０ｍｍ×２００ｍｍの大きさの試料を重量既知の秤量瓶に入れ、１０５℃で２時間乾燥した後の重量を測定し、試料１平方メートルあたりの絶乾重量を算出して、坪量（ｇ／ｍ２）とした。 [Measuring method]
(1) Basis weight A sample having a size of 250 mm × 200 mm is placed in a weighing bottle with a known weight, and the weight after drying at 105 ° C. for 2 hours is measured, and the absolute dry weight per square meter of the sample is calculated. The amount was (g / m 2 ).
（２）付着量
　基紙１平方メートルあたりに塗布した塗工液のウェット重量に塗工液の固形分濃度を乗じて全付着量（ｇ／ｍ２）とした。また、塗工液に含まれるセルロースナノファイバーと吸湿剤の固形分構成比で全付着量を案分してセルロースナノファイバー付着量（ｇ／ｍ２）と吸湿剤付着量（ｇ／ｍ２）を算出した。 (2) Amount of adhesion The total amount of adhesion (g / m 2 ) was obtained by multiplying the wet weight of the coating liquid applied per square meter of the base paper by the solid content concentration of the coating liquid. In addition, the total amount of cellulose nanofibers and moisture absorbent contained in the coating solution is proportionally divided to determine the total amount of cellulose nanofibers deposited (g / m 2 ) and the amount of moisture absorbent adhered (g / m 2 ). Was calculated.
（３）厚さ
　試料を２５℃、３５％ＲＨの恒温恒湿槽内で１時間調和した後、ハイブリッヂ紙厚計で５点の厚さを測定し、平均値を算出して厚さ（μｍ）とした。 (3) Thickness After harmonizing the sample in a constant temperature and humidity chamber at 25 ° C. and 35% RH for 1 hour, measure the thickness at 5 points with a hybrid paper thickness gauge, calculate the average value, and calculate the thickness ( μm).
（４）透湿度
　ＪＩＳ　Ｚ０２０８（１９７６）透湿度（カップ法）に規定する器具を用い、測定環境の温湿度条件を変更して測定を行った。試験片を装着した透湿カップを２０℃、６５％ＲＨに設定した恒温恒湿槽内に２４時間静置して重量増加を測定し、測定面積１平方メートルの２４時間あたりの重量変化を算出して透湿度（ｇ／ｍ２・２４ｈｒ）とした。 (4) Moisture permeability Measurement was performed by changing the temperature and humidity conditions of the measurement environment using an instrument specified in JIS Z0208 (1976) moisture permeability (cup method). The moisture permeable cup equipped with the test piece is left in a constant temperature and humidity chamber set at 20 ° C. and 65% RH for 24 hours to measure the weight increase, and the weight change per 24 hours of the measurement area of 1 square meter is calculated. Thus, the water vapor transmission rate (g / m 2 · 24 hr) was obtained.
（５）透気抵抗度
　ＪＩＳ　Ｐ８１１７（２００９）透気度および透気抵抗度に記載の王研式試験機法に準拠して５回の測定の平均値を算出し、透気抵抗度（王研）（秒）とした。 (5) Air permeability resistance The average value of five measurements was calculated based on the Oken type testing machine method described in JIS P8117 (2009) Air permeability and air resistance, and the air resistance (king Ken) (seconds).
［基紙の製造］
　針葉樹晒クラフトパルプ４０質量％と広葉樹晒クラフトパルプ６０質量％をカナダ標準ろ水度２５０ｍｌＣＳＦになるように混合叩解し、パルプ質量に対してポリアミドポリアミンエピクロルヒドリン系湿潤紙力剤（星光ＰＭＣ株式会社製、商品名：ＷＳ－５３５）を絶乾量で０．２５質量％添加して抄紙原料を調成し、長網式抄紙機で抄紙後、スーパーカレンダー処理して坪量３２ｇ／ｍ2（絶乾重量）の塗工用基紙を得た。 [Manufacture of base paper]
40% by weight of softwood bleached kraft pulp and 60% by weight of hardwood bleached kraft pulp were mixed and beaten to a Canadian standard freeness of 250 ml CSF, and the polyamide polyamine epichlorohydrin wet paper strength agent (made by Seiko PMC Co. Product name: WS-535) was added in an absolute dry amount of 0.25% by mass to prepare a papermaking raw material. After papermaking with a long net paper machine, a super calender treatment was performed, and a basis weight of 32 g / m 2 (absolutely dry) Weight) of base paper for coating.
［カルボキシメチル化セルロースナノファイバーの製造］
　パルプを混ぜることができる撹拌機に、針葉樹晒クラフトパルプ（日本製紙株式会社製）を乾燥質量で２００ｇ、水酸化ナトリウムを乾燥質量で１１１ｇ（発底原料の無水グルコース残基当たり２．２５倍モル）加え、パルプ固形分が２０％（ｗ／ｖ）になるように水を加えた。その後、３０℃で３０分撹拌した後にモノクロロ酢酸ナトリウムを２１６ｇ（有効成分換算、パルプのグルコース残基当たり１．５倍モル）添加した。３０分撹拌した後に、７０℃まで昇温し１時間撹拌した。その後、反応物を取り出して中和、洗浄して、グルコース単位当たりのカルボキシメチル置換度０．２５のカルボキシメチル化したパルプを得た。これを水で固形分１．２％とし、高圧ホモジナイザーにより２０℃、１５０ＭＰａの圧力で５回処理することにより解繊しカルボキシメチル化セルロースナノファイバー（以下、ＣＭ－ＣＮＦという）を得た。平均繊維径は１５ｎｍ、アスペクト比は５０であった。 [Production of carboxymethylated cellulose nanofibers]
In a stirrer capable of mixing pulp, 200 g dry needle bleached kraft pulp (manufactured by Nippon Paper Industries Co., Ltd.) and 111 g sodium hydroxide dry mass (2.25 times mol per anhydroglucose residue of the bottoming material) In addition, water was added so that the pulp solid content was 20% (w / v). Thereafter, after stirring at 30 ° C. for 30 minutes, 216 g of sodium monochloroacetate (in terms of active ingredient, 1.5 times mol per glucose residue of pulp) was added. After stirring for 30 minutes, the temperature was raised to 70 ° C. and stirred for 1 hour. Thereafter, the reaction product was taken out, neutralized and washed to obtain a carboxymethylated pulp having a carboxymethyl substitution degree of 0.25 per glucose unit. This was made into 1.2% solids with water and treated with a high-pressure homogenizer at 20 ° C. and a pressure of 150 MPa five times for fibrillation to obtain carboxymethylated cellulose nanofibers (hereinafter referred to as CM-CNF). The average fiber diameter was 15 nm and the aspect ratio was 50.
＜実施例１＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）９０質量部に水４５質量部と塩化カルシウム（セントラル硝子株式会社製）１７．６質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで上記塗工液を塗工し、乾燥して本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 1>
45 parts by mass of water and 17.6 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The above coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜実施例２＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）９０質量部へ塩化カルシウム（セントラル硝子株式会社製）５．５２質量部を加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し、乾燥して本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 2>
Coating is performed by adding 5.52 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass) and dispersing and dissolving with a bladed stirrer. A liquid was prepared. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜実施例３＞
　塩化カルシウムの配合部を１１．７質量部としたこと以外は実施例２と同様にして本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 3>
A total heat exchange element sheet of the present invention was obtained in the same manner as in Example 2 except that the calcium chloride content was 11.7 parts by mass. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜実施例４＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）６０質量部に水３０質量部と塩化カルシウム（セントラル硝子株式会社製）１１．７質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し、乾燥して本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定して表１に示した。 <Example 4>
30 parts by mass of water and 11.7 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 60 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass) and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, air resistance, and moisture permeability of this paper were measured and shown in Table 1.
［カルボキシル化セルロースナノファイバーの製造］
　針葉樹由来の漂白済み未叩解クラフトパルプ（白色度８５％）５．００ｇ（絶乾）をＴＥＭＰＯ（Ｓｉｇｍａ　Ａｌｄｒｉｃｈ社）３９ｍｇ（絶乾１ｇのセルロースに対し０．０５ｍｍｏｌ）と臭化ナトリウム５１４ｍｇ（絶乾１ｇのセルロースに対し１．０ｍｍｏｌ）を溶解した水溶液５００ｍｌに加え、パルプが均一に分散するまで撹拌した。反応系に次亜塩素酸ナトリウム水溶液を次亜塩素酸ナトリウムが５．５ｍｍｏｌ／ｇになるように添加し、室温にて酸化反応を開始した。反応中は系内のｐＨが低下するが、３Ｍ水酸化ナトリウム水溶液を逐次添加し、ｐＨ１０に調整した。次亜塩素酸ナトリウムを消費し、系内のｐＨが変化しなくなった時点で反応を終了した。
　反応後の混合物をガラスフィルターで濾過してパルプ分離し、パルプを十分に水洗することで酸化されたパルプ（カルボキシル化セルロース）を得た。この時のパルプ収率は９０％であり、酸化反応に要した時間は９０分、カルボキシル基量は１．６ｍｍｏｌ／ｇであった。これを水で１．１％（ｗ／ｖ）に調整し、超高圧ホモジナイザー（２０℃、１５０Ｍｐａ）で３回処理して、カルボキシル化セルロースナノファイバー（以下、Ｔ－ＣＮＦという）の水分散液を得た。平均繊維径は３ｎｍ、アスペクト比は２５０であった。 [Production of carboxylated cellulose nanofibers]
Bleached unbeaten kraft pulp derived from conifers (whiteness 85%), 5.00 g (absolutely dry), 39 mg of TEMPO (Sigma Aldrich) and 0.05 mmol of sodium bromide (absolutely dry) The solution was added to 500 ml of an aqueous solution in which 1.0 mmol) was dissolved in 1 g of cellulose, and stirred until the pulp was uniformly dispersed. An aqueous sodium hypochlorite solution was added to the reaction system so that sodium hypochlorite was 5.5 mmol / g, and the oxidation reaction was started at room temperature. During the reaction, the pH in the system was lowered, but a 3M sodium hydroxide aqueous solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system no longer changed.
The reaction mixture was filtered through a glass filter to separate the pulp, and the pulp was sufficiently washed with water to obtain oxidized pulp (carboxylated cellulose). The pulp yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxyl groups was 1.6 mmol / g. This was adjusted to 1.1% (w / v) with water, treated three times with an ultra-high pressure homogenizer (20 ° C., 150 Mpa), and an aqueous dispersion of carboxylated cellulose nanofiber (hereinafter referred to as T-CNF) Got. The average fiber diameter was 3 nm and the aspect ratio was 250.
＜実施例５＞
　Ｔ－ＣＮＦの水分散液（固形分濃度１．１質量％）１２０質量部に水６０質量部と塩化カルシウム（セントラル硝子株式会社製）２５．２質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し乾燥してＴ－ＣＮＦと塩化カルシウムの片面塗工紙を得た。この片面塗工紙の反対面に、Ｔ－ＣＮＦの水分散液（固形分濃度１．１質量％）９０質量部へ水４５質量部を加えて翼付撹拌機で分散した塗工液をマイヤーバーで塗工後、乾燥して両面に塗工が施された本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 5>
60 parts by mass of water and 25.2 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 120 parts by mass of an aqueous dispersion of T-CNF (solid concentration: 1.1% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating liquid was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of T-CNF and calcium chloride. On the other side of this single-sided coated paper, 45 parts by mass of water was added to 90 parts by mass of an aqueous T-CNF dispersion (solid content concentration: 1.1% by mass), and the coating liquid dispersed with a bladed stirrer was applied to Meyer. After coating with a bar, the sheet was dried to obtain the total heat exchange element paper of the present invention coated on both sides. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
［カチオン化セルロースナノファイバーの製造］
　パルプを撹拌することができるパルパーに、針葉樹晒クラフトパルプ（日本製紙株式会社製）を乾燥重量で２００ｇ、水酸化ナトリウムを乾燥重量で２４ｇ加え、パルプ固形濃度が１５％になるように水を加えた。その後、３０℃で３０分撹拌した後に７０℃まで昇温し、カチオン化剤として３－クロロ－２－ヒドロキシプロピルトリメチルアンモニウムクロライドを２００ｇ（有効成分換算）添加した。１時間反応した後に、反応物を取り出して中和、洗浄して、グルコース単位当たりのカチオン置換度０．０５のカチオン変性されたパルプを得た。これを固形濃度１．２％とし、高圧ホモジナイザーにより２０℃、１４０ＭＰａの圧力で２回処理しカチオン化セルロースナノファイバー（以下、Ｃ－ＣＮＦという）を得た。平均繊維径は２５ｎｍ、アスペクト比は５０であった。 [Production of cationized cellulose nanofibers]
To pulper that can stir the pulp, add 200g by dry weight of softwood bleached kraft pulp (manufactured by Nippon Paper Industries Co., Ltd.) and 24g by weight of sodium hydroxide, and add water so that the pulp solid concentration is 15%. It was. Then, after stirring at 30 ° C. for 30 minutes, the temperature was raised to 70 ° C., and 200 g (in terms of active ingredient) of 3-chloro-2-hydroxypropyltrimethylammonium chloride was added as a cationizing agent. After reacting for 1 hour, the reaction product was taken out, neutralized and washed to obtain a cation-modified pulp having a cation substitution degree of 0.05 per glucose unit. This was adjusted to a solid concentration of 1.2% and treated twice with a high-pressure homogenizer at 20 ° C. and a pressure of 140 MPa to obtain cationized cellulose nanofibers (hereinafter referred to as C-CNF). The average fiber diameter was 25 nm and the aspect ratio was 50.
＜実施例６＞
　Ｃ－ＣＮＦの水分散液（固形分濃度１．２質量％）９０質量部に水４５質量部と塩化カルシウム（セントラル硝子株式会社製）１７．６質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し乾燥してＣ－ＣＮＦと塩化カルシウムの片面塗工紙を得た。この片面塗工紙の反対面に、Ｃ－ＣＮＦの水分散液（固形分濃度１．２質量％）９０質量部へ水４５質量部を加えて翼付撹拌機で分散した塗工液をマイヤーバーで塗工、乾燥して両面に塗工が施された本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 6>
45 parts by weight of water and 17.6 parts by weight of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by weight of an aqueous dispersion of C-CNF (solid content concentration: 1.2% by weight) and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of C-CNF and calcium chloride. On the other side of this single-sided coated paper, 45 parts by mass of water was added to 90 parts by mass of an aqueous dispersion of C-CNF (solid content concentration 1.2% by mass), and the coating liquid dispersed with a bladed stirrer was Meyer. The total heat exchange element paper of the present invention, which was coated with a bar and dried to be coated on both sides, was obtained. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜実施例７＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）９０質量部に水４５質量部と塩化カルシウム（セントラル硝子株式会社製）１７．６質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し乾燥してＣＭ－ＣＮＦと塩化カルシウムの片面塗工紙を得た。この片面塗工紙の反対面に、ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）６０質量部へ水３０質量部を加えて翼付撹拌機で分散した塗工液をマイヤーバーで塗工、乾燥して両面に塗工が施された本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 7>
45 parts by mass of water and 17.6 parts by mass of calcium chloride (manufactured by Central Glass Co., Ltd.) are added to 90 parts by mass of an aqueous CM-CNF dispersion (solid content: 1.2% by mass), and dispersed with a bladed stirrer. Then, it was dissolved to prepare a coating solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain a single-side coated paper of CM-CNF and calcium chloride. On the other side of this single-sided coated paper, 30 parts by weight of water was added to 60 parts by weight of an aqueous CM-CNF dispersion (solid concentration 1.2% by weight), and the coating liquid dispersed with a bladed stirrer was Meyer. The total heat exchange element paper of the present invention, which was coated with a bar and dried to be coated on both sides, was obtained. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜実施例８＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）６０質量部に水３０質量部と酢酸カリウム（和光純薬工業株式会社製）３．６質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し、乾燥して本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。
結果を表１に示す。 <Example 8>
30 parts by weight of water and 3.6 parts by weight of potassium acetate (manufactured by Wako Pure Chemical Industries, Ltd.) were added to 60 parts by weight of an aqueous CM-CNF dispersion (solid content 1.2% by weight), and a bladed stirrer The coating solution was prepared by dispersing and dissolving the solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured.
The results are shown in Table 1.
＜実施例９＞
　ＣＭ－ＣＮＦの水分散液（固形分濃度１．２質量％）６０質量部に水３０質量部と塩化リチウム（和光純薬工業株式会社製）３．６質量部とを加えて翼付撹拌機で分散、溶解して塗工液を調製した。基紙の片面にマイヤーバーで前記塗工液を塗工し、乾燥して本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。 <Example 9>
30 parts by mass of water and 3.6 parts by mass of lithium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were added to 60 parts by mass of an aqueous dispersion of CM-CNF (solid content concentration 1.2% by mass), and a bladed stirrer The coating solution was prepared by dispersing and dissolving the solution. The coating solution was applied to one side of the base paper with a Meyer bar and dried to obtain the total heat exchange element paper of the present invention. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
＜ブロッキング性評価＞
　実施例５の両面塗工紙から５０ｍｍ×８０ｍｍの試験片２枚を切り出し、Ｆ面（フェルト面）側とＷ面（ワイヤー面）側を重ね、２０℃、７５％ＲＨの恒温恒湿槽内で１５分間調和した後、ロール温度９０℃、ロール線圧４０ｋｇ／ｃｍの１ニップ式カレンダー装置（由利ロール機械株式会社製）を通して２枚の試験片を圧着した。圧着した試験片の長手方向の一端を少し剥がし、１枚の端部をデジタルフォースゲージ（日本電産シンポ株式会社製、装置名：ＦＧＰ－０．５型）に装着した試料掴み部に挟み、他の１枚の端部を手でつかんで引張り、長手方向に約７０ｍｍ剥がして剥離抵抗の最大値を読み取り、試料幅５ｃｍあたりの剥離抵抗とした。熱圧ロールを用いて強制圧着された試験片の剥離抵抗は５０ｇ／５ｃｍ以下であり、ブロッキング性は極めて弱いと評価した。
　また、その他の実施例のブロッキング性においても、圧着させた一部が剥がれず、母材が破壊されることはなかった。 <Evaluation of blocking properties>
Two 50 mm × 80 mm test pieces were cut out from the double-sided coated paper of Example 5, the F surface (felt surface) side and the W surface (wire surface) side were stacked, and in a constant temperature and humidity chamber at 20 ° C. and 75% RH. Then, two test pieces were pressure-bonded through a 1-nip calender device (manufactured by Yuri Roll Machinery Co., Ltd.) having a roll temperature of 90 ° C. and a roll linear pressure of 40 kg / cm. One end in the longitudinal direction of the bonded test piece is peeled off slightly, and one end is sandwiched between sample grips attached to a digital force gauge (manufactured by Nidec Shinpo Co., Ltd., device name: FGP-0.5 type), The other end of the sheet was grasped by hand and pulled, peeled about 70 mm in the longitudinal direction, and the maximum value of the peel resistance was read to obtain the peel resistance per 5 cm of the sample width. The peel resistance of the test piece force-bonded using a hot-press roll was 50 g / 5 cm or less, and the blocking property was evaluated to be extremely weak.
Moreover, also in the blocking properties of the other examples, a part of the pressure-bonding did not peel off, and the base material was not destroyed.
＜比較例１＞
　ＣＭ－ＣＮＦを無配合としたこと以外は実施例１と同様にして本発明の全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。なお、基紙はカレンダー処理での高密度化により紙厚が薄く、透気抵抗度が高くなっていたが、塗工過程による湿潤と乾燥作用により密度、厚さ、透気抵抗度はカレンダー処理前に近い状態に戻り、紙厚が厚く、透気抵抗度が低くなった。
＜比較例２＞
　塩化カルシウムを無配合とし、ＣＭ－ＣＮＦ付着量が０．３ｇ／ｍ2となるようにした以外は実施例１と同様にして全熱交換素子用紙を得た。この用紙について付着量、透気抵抗度、透湿度を測定した。結果を表１に示す。
＜比較例３＞
　塗工を行っていない基紙について透気抵抗度、透湿度を測定した。結果を表１に示す。 <Comparative Example 1>
A total heat exchange element paper of the present invention was obtained in the same manner as in Example 1 except that CM-CNF was not used. The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1. The base paper had a thin paper thickness due to densification by calendering, and the air resistance was high. However, the density, thickness, and air resistance were calendered by the wet and dry action during the coating process. Returning to the previous state, the paper thickness was thick and the air resistance was low.
<Comparative example 2>
A total heat exchange element paper was obtained in the same manner as in Example 1 except that calcium chloride was not added and the amount of CM-CNF adhered was 0.3 g / m 2 . The adhesion amount, the air resistance, and the moisture permeability of this paper were measured. The results are shown in Table 1.
<Comparative Example 3>
The air resistance and moisture permeability of the base paper that was not coated were measured. The results are shown in Table 1.
＜比較例４＞
　坪量５５ｇ／ｍ２の難燃紙（透気抵抗度　４秒）の片面に、固形分換算でポリビニルアルコール（株式会社クラレ製）１４質量部、塩化リチウム（和光純薬工業株式会社製）１０質量部、水７６質量部からなる塗工液を塗布、乾燥して、片面に吸湿剤を含む水溶性高分子層が塗工された全熱交換素子用紙を作製した。この用紙の吸湿剤塗布量は固形分換算で２．５ｇ／ｍ２、ポリビニルアルコール塗布量は固形分換算で３．５ｇ／ｍ２であった。透気抵抗度は２３０００秒、透湿度は１２００ｇ／ｍ２・２４ｈｒであり、全熱交換素子用紙として十分な空気遮蔽性と透湿性を有していた。
　この用紙について、前記ブロッキング性評価と同様の方法で熱圧ロールを用いた強制圧着試験を行い、剥離抵抗を測定した結果、剥離抵抗が３００ｇ／ｃｍ以上と極めて大きく、一部は剥がれずに母材が破壊したため、ブロッキング性が非常に強いと評価した。 <Comparative example 4>
On one side of a flame-retardant paper having a basis weight of 55 g / m 2 (air permeability resistance 4 seconds), 14 parts by mass of polyvinyl alcohol (manufactured by Kuraray Co., Ltd.) and lithium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) 10 in terms of solid content A coating liquid consisting of part by mass and 76 parts by mass of water was applied and dried to prepare a total heat exchange element sheet coated with a water-soluble polymer layer containing a hygroscopic agent on one side. The amount of moisture absorbent applied to this paper was 2.5 g / m 2 in terms of solid content, and the amount of polyvinyl alcohol applied was 3.5 g / m 2 in terms of solid content. The air permeation resistance was 23000 seconds, and the water vapor transmission rate was 1200 g / m 2 · 24 hr, and had sufficient air shielding and moisture permeability as a total heat exchange element paper.
The paper was subjected to a forced pressure bonding test using a hot-pressing roll in the same manner as in the evaluation of the blocking property, and the peel resistance was measured. As a result, the peel resistance was as extremely high as 300 g / cm or more, and part of the mother was not peeled off. Since the material was broken, it was evaluated that the blocking property was very strong.
　実施例１～９から明らかなように、高叩解しない原料からなる基紙を用いても、セルロースナノファイバーを配合した塗工層を設けることにより、透湿性を低下させることなく透気抵抗度を高めることができる。また、両面塗工した場合でも片面塗工の透湿度を維持して透気抵抗度を大幅に高めることができる。 As is apparent from Examples 1 to 9, even when a base paper made of a raw material that is not highly beaten is used, by providing a coating layer containing cellulose nanofibers, air permeability resistance can be reduced without reducing moisture permeability. Can be increased. Moreover, even when double-sided coating is performed, the moisture permeability of the single-sided coating can be maintained and the air resistance can be greatly increased.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  

Claims (6)

  1. 　製紙用繊維、吸湿剤、セルロースナノファイバーを含有することを特徴とする全熱交換素子用紙。 Total heat exchange element paper characterized by containing fiber for papermaking, hygroscopic agent, and cellulose nanofiber.
  2. 　前記製紙用繊維が、セルロース繊維であることを特徴とする請求項１に記載の全熱交換素子用紙。 The total heat exchange element paper according to claim 1, wherein the papermaking fiber is a cellulose fiber.
  3. 　前記セルロースナノファイバーが、カルボキシメチル化セルロースナノファイバー、カルボキシル化セルロースナノファイバー、カチオン化セルロースナノファイバー、エステル化セルロースナノファイバーの少なくとも一種であることを特徴とする請求項１または２に記載の全熱交換素子用紙。 The total heat according to claim 1 or 2, wherein the cellulose nanofiber is at least one of carboxymethylated cellulose nanofiber, carboxylated cellulose nanofiber, cationized cellulose nanofiber, and esterified cellulose nanofiber. Replacement element paper.
  4. 　前記吸湿剤が、アルカリ金属塩、アルカリ土類金属塩のいずれかであることを特徴とする請求項１～３のいずれかに記載の全熱交換素子用紙。 The total heat exchange element paper according to any one of claims 1 to 3, wherein the hygroscopic agent is an alkali metal salt or an alkaline earth metal salt.
  5. 　透気抵抗度が７００秒以上であることを特徴とする請求項１～４のいずれかに記載の全熱交換素子用紙。 The total heat exchange element paper according to any one of claims 1 to 4, wherein the air permeation resistance is 700 seconds or more.
  6. 　製紙用繊維からなる基紙の少なくとも片面に、吸湿剤とセルロースナノファイバーとを含有する薬液を塗工することを特徴とする全熱交換素子用紙の製造方法。
     
     
     
     
          A method for producing a total heat exchange element paper, wherein a chemical solution containing a hygroscopic agent and cellulose nanofibers is applied to at least one surface of a base paper made of papermaking fibers.




PCT/JP2017/021890 2016-06-28 2017-06-14 Paper for energy recovery ventilation element WO2018003492A1 (en)

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