EP2761081B1 - Enzymatic pretreatment of wood in a method for producing mechanical paper pulp - Google Patents
Enzymatic pretreatment of wood in a method for producing mechanical paper pulp Download PDFInfo
- Publication number
- EP2761081B1 EP2761081B1 EP12767039.6A EP12767039A EP2761081B1 EP 2761081 B1 EP2761081 B1 EP 2761081B1 EP 12767039 A EP12767039 A EP 12767039A EP 2761081 B1 EP2761081 B1 EP 2761081B1
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- EP
- European Patent Office
- Prior art keywords
- wood
- mechanical
- pulp
- refining
- composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/02—Pretreatment of the raw materials by chemical or physical means
- D21B1/021—Pretreatment of the raw materials by chemical or physical means by chemical means
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/02—Pretreatment of the raw materials by chemical or physical means
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
- D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
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- 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
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
Definitions
- the present invention relates to a method of manufacturing mechanical pulp. It also relates to a composition used in this process and to the use of this composition in a process for manufacturing mechanical pulp. Finally, it relates to a papermaking process.
- Paper pulps called “mechanical pulp” or “high-performance pulps” or “wood pulp” are obtained directly from the wood by a series of mechanical treatments, generally grouped under the name “mechanical refining”, carried out by means of grinding wheels and / or refiners.
- the mechanical paper stock is then subjected to a bleaching phase which may comprise one or more stages depending on the degree of whiteness required.
- the advantage of a mechanical pulping process is its high material yield, compared to a so-called "chemical” pulping process. Indeed, unlike chemical pulping processes in which the lignin present in the raw wood is eliminated almost completely by cooking in the presence of chemicals, about 90% of the raw wood is preserved in the pasta obtained in the pasta. from a process for manufacturing mechanical pulp.
- Mechanical refining of a mechanical pulp manufacturing process typically involves several refining steps, such as primary refining generally referred to as "defibration", secondary refining, tertiary refining, refining of classification rejects, and the like. These refining steps provide pastes with different degrees of refinement, in order to gradually transform the wood into individualized fibers and thus enable the manufacture of paper pulp.
- Mechanical refining has the disadvantage of being a major consumer of energy, typically from 1500 to 3000 kWh per ton of mechanical pulp produced. This energy represents on the one hand a significant cost and on the other hand, it is likely to damage the wood fibers. Also different ways have been considered to reduce the energy to bring.
- the document EP 1728917 proposes to carry out a low consistency refining, that is to say with a low dry matter content of pulp.
- a low consistency refining that is to say with a low dry matter content of pulp.
- such a treatment requires a large number of equipment and its effectiveness remains limited.
- WO 08081078 proposes, for its part, a mechanical pulp manufacturing process comprising a step of treatment with ozone during the refining.
- this treatment has the disadvantage of creating chromophore groups on the polysaccharide molecules contained in the wood, which prove difficult to oxidize when conventional bleaching of the paste is then implemented.
- the documents EP 429422 and WO 91/11552 also disclose processes for manufacturing mechanical pulp comprising an enzymatic pretreatment step of a fibrous material to facilitate subsequent refining.
- the redox potential of the described enzymes is adjusted by means of regulators such as nitrogen or oxygen gas, antioxidants, sugars, organic acids or inorganic salts.
- regulators such as nitrogen or oxygen gas, antioxidants, sugars, organic acids or inorganic salts.
- WO 91/11552 it is recommended to carry out enzymatic pre-treatment below a certain redox potential.
- adjusting the redox potential of the enzymes is a delicate operation to implement and is expensive.
- the document EP 0745 154 discloses a method of manufacturing chemical pulp using a multi-component system for the modification, decomposition or decolorization of lignin, including an oxidoreductase enzyme, a mediator, a free amine and an oxidizing agent. This system is used to whiten a chemical pulp previously delignified with oxygen. This system has the drawbacks of generating effluents that are harmful to the environment and to generate high production costs.
- the present invention relates to a method of manufacturing a mechanical paper stock to overcome the above drawbacks.
- the invention also relates to the impregnating composition used in this process.
- the invention also relates to the use of said impregnating composition in a mechanical pulp manufacturing process for lowering the energy consumption of said process.
- the invention further relates to the use of said impregnating composition in a process for manufacturing mechanical pulp to increase the whiteness of said paste.
- the invention also relates to the use of said impregnating composition in a process for manufacturing mechanical pulp comprising a mechanical refining step, said impregnating composition being used before the mechanical refining step.
- the subject of the invention is a papermaking process, comprising the manufacture of a mechanical paper pulp according to the above method, as well as the use of this mechanical paper pulp to produce paper.
- the present invention overcomes the disadvantages of the state of the art.
- it provides a method of manufacturing mechanical pulp more energy-efficient and which guarantees a pulp and paper paper qualities equivalent or improved over known methods.
- It also provides a mechanical pulp having a higher degree of whiteness at the end of the refining and / or developing a better bleaching ability compared to mechanical pulps obtained with the known methods.
- the invention also makes it possible to reduce the quantity of chemicals to be used for bleaching the mechanical paper pulp, while guaranteeing a degree of whiteness at the end of bleaching at least equivalent to or even greater than that of mechanical paper pulps. produced with the known methods. This is accomplished by a wood impregnation step with a particular impregnating composition prior to refining.
- the composition according to the invention oxidizes the phenolic and non-phenolic units of the lignin, which leads to weakening of the bonds between the fibers.
- the Applicant has in particular developed an impregnating composition that acts specifically on the cell wall of the fibers, to reduce the cohesion between the fibers while preserving them. Also, when the composition of the invention is used on a wood before refining, it reduces the energy that it would be necessary to provide during the refining to separate the wood fibers if no pretreatment was performed or if a method of the state of the art was implemented in its place. In addition, the length of the fibers from the starting wood and their strength are preserved in the manufactured mechanical pulp and in the paper that is derived therefrom.
- the impregnating composition according to the invention is inexpensive, available in large quantities and less toxic to the environment.
- immediateer a compound which improves the ability of an enzyme to oxidize a wood.
- wood all secondary resistant tissues (support, conduction, and storage) which form the trunks, branches and roots of woody plants, within the meaning of standard NF B 50-003.
- raw wood is meant the state of a wood before its treatment with an impregnating composition according to the invention and "impregnated” wood means the state of a wood after its treatment with an impregnating composition according to the invention.
- Dry wood means that the wood has been kiln-dried in accordance with ISO 638: 2008, ie at a temperature of between 103 ° C and 107 ° C, for a period of not less than 30 minutes and not exceeding not 16 hours at atmospheric pressure.
- the "consistency" of mechanical pulp refers to the pulp concentration as defined in ISO Standard 4119 of June 1996. This is the ratio of the dry mass of filterable material to a suspended pulp sample, to the mass of the unfiltered sample, the test being carried out in accordance with said International Standard.
- the paste concentration is expressed as a percentage by mass.
- dry mechanical paper pulp is meant the dry mass of material of a suspended pulp sample as defined in the abovementioned ISO standard 4119, being measured after filtering and drying in accordance with said standard.
- Raw wood is used as raw material.
- the raw wood is selected from softwoods, hardwoods or mixtures thereof.
- Suitable softwoods include Douglas fir, Spruce, Aleppo pine, Maritime pine, Black pine, Scots pine, Taeda pine, Red cedar ( Thulya plicata ) or mixtures thereof.
- Suitable hardwoods include poplar, aspen, birch, maple, oak, eucalyptus, acacia, beech, chestnut, hornbeam, alder or mixtures thereof.
- spruce, poplar, eucalyptus or a mixture thereof is used.
- the raw wood in order to manufacture a chemomercomechanical pulp (CTMP), may be chosen from softwoods such as those mentioned above, hardwoods such as those mentioned above, or bamboo, hemp, cereal straw, for example wheat straw or rice straw, cotton or mixtures thereof.
- softwoods such as those mentioned above
- hardwoods such as those mentioned above
- bamboo bamboo, hemp, cereal straw, for example wheat straw or rice straw, cotton or mixtures thereof.
- the raw wood is in the form of chips.
- chips is used in the conventional sense for those skilled in the art. It designates wood particles that can be obtained by any industrial process conventionally used in the field of mechanical pulp.
- the chip size is typically distributable according to the standard SCAN-CM 40:01. This form facilitates the subsequent impregnation treatment of the wood and improves its effectiveness.
- the chips can typically be obtained from debarked and cut raw logs or residual by-products from the wood industry.
- the wood undergoes, before or after the impregnation step, preferably before the impregnation step, at least one pretreatment chosen from a heat pretreatment, a chemical pretreatment, a mechanical pretreatment or a combination of these.
- Suitable heat pretreatment include steam steaming, hot water treatment or a combination thereof.
- a suitable chemical pretreatment there may be mentioned a wood impregnation treatment with at least one chemical agent chosen from an acid, a base, an oxidant, a reducing agent, a chelator, a stabilizer, a surfactant, an enzyme or their mixtures.
- suitable mechanical pretreatment there may be mentioned a pressing.
- the wood undergoes, before or after the impregnation step, preferably before the impregnation step, steam steaming, which makes it possible to homogenize the dryness of the wood.
- Stoving includes contacting the wood with water vapor. Steaming is preferably carried out at atmospheric pressure. Stoving preferably has a duration of from 5 to 30 minutes, more preferably from 10 to 20 minutes.
- the raw wood undergoes, before or after the impregnation step, preferably before the impregnation step, a pressing.
- the pressing can be carried out using any means known to those skilled in the art, preferably with the aid of a compression device such as a screw press or a cylinder press.
- the raw wood is initially in the form of chips and the chips are steam-steamed as defined above; according to another preferred embodiment, the raw wood undergoes, before the impregnation step, a steam steaming followed by pressing as defined above.
- the wood does not undergo chemical pretreatment before the impregnation step, in particular no acid wash or chelation treatment.
- the various pretreatments mentioned above may be used before or after the impregnation step. They can be repeated if needed. For example, one of these pretreatments can be used before the impregnation step, the impregnation step can be carried out and then the said pretreatment can be repeated after the impregnation step.
- the manufacturing method according to the invention comprises a step of impregnating a raw wood, comprising contacting the raw wood with an impregnating composition according to the invention so as to obtain an impregnated wood.
- Said impregnation composition comprises at least one laccase enzyme and a mediator of particular formula.
- the impregnating composition according to the invention thus comprises a mediator of formula (I): in which R1 and R2 are identical or different groups chosen from a hydrogen atom or a C1-C4 alkyl chain.
- R1 and R2 are identical or different C1 to C4 alkyl chains. More preferably, R1 and R2 are identical alkyl chains of the formula C2H5: the preferred mediator is thus diethyl hydroxylamine (DEHA).
- DEHA diethyl hydroxylamine
- the mediator may be present in the impregnating composition in pure form, in solution in water or in the form of one of its salts.
- the mediator content in the impregnating composition is preferably from 0.1% to 10% by weight, preferably from 0.15% to 4.5% by weight, preferably from 0.19% to 4% by weight. weight, preferably from 0.19% to 3% by weight, or even from 0.23% to 2% by weight relative to the total weight of the impregnating composition.
- the mediator content relative to the dry raw wood mass to be treated, is preferably from 0.1% to 10%, from 0.2% to 10%, from 0.2% to 5%, more preferably from 0.2% to 0.5%, or even 0.25% to 0.5%, by weight of dry wood.
- the enzyme laccase may be selected from class EC 1.10.3.2 of the Enzyme Nomenclature. Myceliophthora laccase is particularly preferred.
- the laccase enzyme may be in the form of a crude extract, in purified or semi-purified form.
- the solution content of the laccase at 1000 LAMU / ml, relative to the dry raw wood mass to be treated, is preferably from 0.1 to 10 L / t, from 1 to 5 L / t, more preferably from 1 to 2 L / t of dry raw wood.
- the solution content of 1000 LAMU / ml laccase in the impregnating composition is preferably from 0.01% to 10% by weight, from 0.05% to 5% by weight. weight, from 0.05% to 1% by weight, in particular from 0.09% to 0.2% by weight, relative to the total weight of the impregnating composition.
- the impregnating composition according to the invention may further comprise one or more additives customary to the person skilled in the art, provided that their presence does not detract from the effectiveness of the composition.
- additives may especially be chosen from: an enzyme other than laccase, an oxidant, a reducing agent, an acid, a base, a chelating agent, a stabilizer, a surfactant, their combinations.
- the total additive content in the impregnating composition is preferably less than 3% by weight, in particular less than 2% by weight, relative to the total weight of the composition.
- the impregnating composition does not comprise an additive.
- the impregnating composition is an aqueous solution.
- the water content of the composition then corresponds to the complement at 100% by weight of the sum of the contents of mediator, enzyme and possible additives.
- the impregnating composition is used at a rate of 0.1 to 12 L / kg of dry raw wood to be impregnated, preferably at a rate of 1 to 10 L / kg of the raw wood to be impregnated.
- the excess impregnating composition may advantageously be recycled to perform a new impregnation step on another raw wood or on the impregnated wood.
- the contacting of the raw wood with the impregnating composition comprises (or even consists of) a vaporization of the impregnating composition on the raw wood or an immersion of the raw wood in a composition bath. impregnation.
- the raw wood is immersed in the impregnating composition for a time sufficient to allow impregnation of the wood impregnating composition, then the wood is removed from the composition and incubated for a sufficient period of time to allow the enzyme to act on the wood.
- the raw wood is immersed in the impregnating composition and is allowed to incubate for a time sufficient to allow the enzyme to act on the wood. Incubation may be carried out in any suitable device known to those skilled in the art, for example in a storage cabinet.
- the contacting of the raw wood with the impregnating composition is carried out by spraying raw wood chips, compressed from a compression screw directly into a bath of impregnating composition. This allows optimal chip absorption (the chips sucking the composition in the manner of a sponge) and promotes the action of the composition in the heart of the wood fibers.
- the contacting of the raw wood with the impregnating composition is preferably carried out for a duration ranging from 5 minutes to 240 minutes, from 25 minutes to 180 minutes, from 45 minutes to 120 minutes, more preferably 55 minutes. at 65 min.
- the impregnating composition is preferably carried out at a temperature of 35 to 80 ° C, 40 to 70 ° C, more preferably 45 to 55 ° C. It is preferably carried out at a pH ranging from 3 to 11, from 4 to 7, more preferably from 4.5 to 5.5. Such conditions are advantageous for optimizing the effectiveness of the composition according to the invention.
- the impregnation stage can be stopped by steaming (contacting the impregnated wood with steam) or washing with water, in order to stop the activity of the enzyme.
- the duration of steaming or washing with water is preferably from 1 to 10 minutes, more preferably from 3 to 7 minutes.
- steaming is carried out at atmospheric pressure.
- the impregnation step may be repeated several times, in particular two to four times.
- the various embodiments mentioned above can also be combined with each other.
- the impregnating composition can be prepared separately and then brought into contact with the raw wood, as explained above, but it can also be prepared directly in contact with the raw wood. In this case, the various compounds of the impregnating composition are added successively and directly to the raw wood.
- the wood can be subjected to a complementary treatment, called post-treatment.
- This post-treatment comprises contacting with a chemical composition comprising an alkaline agent and a reducing agent.
- This post-treatment is advantageous for softening the lignin and developing the mechanical characteristics of the fibers.
- CMP chemo-thermomechanical pulp
- This step is preferably carried out after the impregnation step to avoid a potential inhibition of the enzymes of the impregnating composition. It can be implemented before or after the refining step. It is preferably carried out between the impregnation stage and the refining stage, which makes it possible to increase the energy saving of the refining.
- the contacting of the wood with the chemical composition comprises a vaporization of said composition on the wood or immersion of the wood in a bath of said composition.
- the alkaline agent is selected from sodium hydroxide, magnesium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, sodium silicate, or mixtures thereof.
- the alkaline agent is chosen from sodium silicate, sodium hydroxide or their mixture.
- the reducing agent is chosen from sodium sulphite Na 2 S 2 O 3 , sodium bisulfite NaHSO 3 or their mixture.
- the alkaline agent is present in a content ranging from 0.1% to 20% by weight, preferably from 1% to 10% by weight, relative to the weight of wood.
- the reducing agent is present in a content ranging from 0.1% to 30% by weight, preferably from 1% to 20% by weight, relative to the weight of wood.
- the chemical post-treatment step is preferably carried out at a temperature of from 10 ° C to 150 ° C, in particular from 60 ° C to 120 ° C. It is preferably carried out for a time ranging from 1 minute to 120 minutes, preferably from 1 to 60 minutes.
- the chemical post-treatment step may be terminated by any means for stopping the reaction of the chemical agents on the wood, for example by washing with water.
- the chemical post-treatment step can be repeated several times, in particular twice to four times, which makes it possible to further reinforce the papermaking capabilities of the fibers.
- mechanical refining of the impregnated wood is carried out so as to obtain a mechanical pulp.
- Mechanical refining includes a primary mechanical refining (also known as pulping), intended to pulp the wood possibly, followed by at least a secondary mechanical refining, intended to develop the papermaking capabilities of the fibers. Secondary refining is eventually followed by one or more subsequent mechanical refining (tertiary refining, refining of refusals, etc.).
- the mechanical refining is preferably carried out under pressure so as to allow a more selective separation of the fibers.
- Primary refining can be carried out by grinding or grating the wood with the grinding wheel (under water flow) or in a disc refiner.
- the primary refining of the wood is carried out in a disc refiner.
- the pressure is preferably adjusted so as to reach a refining temperature of between 105 ° C and 115 ° C.
- the pressure ranges from 0.5 to 5 bar, preferably from 1 to 3 bar.
- the rotational speed of the discs is preferably from 1000 to 5000 rpm, preferably from 1000 to 3000 rpm.
- the secondary refining of the wood is carried out in a disc refiner.
- the secondary refining is preferably carried out at a pressure of from 0.1 to 5 bar, preferably from 0.5 to 3 bar.
- the rotational speed of the discs is preferably from 1000 to 5000 rpm, preferably from 1000 to 3000 rpm.
- the secondary refining is carried out so as to have at its disposal dough rate pasta ranging from 250 to 50 mL CSF ( Canadian Standard Freeness ).
- the refining step (s) subsequent to defibration can comprise several stages.
- the product can be separated into an accepted fraction and a rejected fraction, and the rejected fraction refined before mixing with the accepted fraction. It is possible to provide for such intermediate separations several times.
- a mechanical paper pulp is obtained, preferably having a degree of whiteness, measured according to ISO 2470, greater than or equal to 50%, preferably greater than or equal to 55%, ideally greater than or equal to at 57%.
- the specific energy saving achieved by virtue of the invention is advantageously greater than or equal to 10%, even greater than or equal to 12%, even greater than or equal to 14%, even greater than or equal to 18%, or even greater than or equal to 32%. %, compared to a process for manufacturing a mechanical paper pulp obtained by refining a wood pre-impregnated under the same conditions but with water.
- the chelation when used, preferably occurs after the impregnation stage (that is to say once the impregnation stage is complete), advantageously after the refining, in order to avoid a possible inhibitory interaction with the enzyme.
- the chelation comprises contacting the mechanical pulp resulting from the refining with a chelating composition comprising a chelating agent, said chelating composition preferably being an aqueous solution.
- the chelating agent may be any chemical compound conventionally used for this purpose in the field.
- it is ethylene diamine tetraacetic acid or a sodium salt thereof, or diethylene triamine penta-acetic acid or a sodium salt thereof.
- the chelating agent has a particular affinity for trace metal cations in mechanical pulp.
- the purpose of the chelation treatment is to neutralize these cations by sequestering them and to remove them from the mechanical paper pulp by washing it.
- the completion of the chelation step contributes to improving the performance of a subsequent bleaching treatment (in particular with hydrogen peroxide).
- the amount of chelating agent used in the chelation step is preferably from 0.05% to 3% by weight, preferably from 0.1% to 2% by weight, preferably from 0.2% to 1% by weight. % by weight, in particular from 0.3% to 0.5% by weight, relative to the weight of dry mechanical pulp.
- the duration of the chelation step is preferably greater than or equal to about 30 minutes.
- the chelation step is carried out at a temperature of preferably 4 ° C to 95 ° C, preferably 25 ° C to 85 ° C, more preferably 35 ° C to 80 ° C. A temperature of about 60 ° C is particularly suitable.
- the consistency of the mechanical paper stock in the chelation step is preferably 0.5% to 20% by weight of dry mechanical paper stock, preferably 2 to 15% by weight of dry mechanical stock more preferably from 3 to 12% by weight of dry mechanical pulp, relative to the weight of dry mechanical pulp.
- the bleaching preferably occurs after the chelation (or after refining if the chelation is absent), that is to say once the chelation step (or the refining step if the chelation is absent) is completed. .
- Bleaching comprises contacting the mechanical paper pulp from the chelation step (or refining if the chelation is absent) with a bleaching composition.
- the consistency during the bleaching step is preferably from 1% to 50% by weight of dry mechanical pulp, preferably from 10 to 40% by weight of dry mechanical pulp, more preferably from 20 to 30% by weight. % by weight of dry mechanical pulp, relative to the weight of dry mechanical pulp.
- Bleaching has faster reaction kinetics at high consistency (whereas for chelation reaction kinetics are fast even at low consistency).
- the consistency of the mechanical paper stock can be increased by pressing it, for example, and by eliminating filtrates comprising in particular the chelated metals.
- the contacting is preferably by simple mixing of the bleaching composition with the paper pulp.
- the type of equipment used for mixing is adapted according to the consistency of the pulp: direct mixing by means of an injection pump if the consistency is low or medium (less than 10%); mixer or mixer for a higher consistency (up to about 40%).
- the bleaching composition is preferably an aqueous solution.
- the bleaching composition preferably comprises a bleaching agent and an alkaline agent.
- the bleaching agent may be any chemical compound conventionally used for this purpose in the field. Preferably it is hydrogen peroxide or sodium hydrosulfite.
- the amount of bleaching agent used is preferably from 0.5% to 10% by weight, preferably from 1% to 8% by weight, preferably from 1.5% to 6% by weight. weight, in particular from 2% to 4% by weight, relative to the weight of dry mechanical pulp.
- the alkaline agent may be selected from oxides, hydroxides, silicates and carbonates of alkali metals and alkaline earth metals, ammonia, ammonia and mixtures thereof.
- the basic species preferred for the choice of the alkaline agent mention may be made of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, sodium silicate magnesium carbonate and mixtures thereof.
- Sodium hydroxide, potassium hydroxide or their mixture is particularly preferred.
- the alkaline agent of the bleaching composition comprises sodium silicate.
- Sodium silicate has an auxiliary stabilizing function of the bleaching agent (especially hydrogen peroxide). It is also possible to provide in the bleaching composition another stabilizing agent in addition to or instead of sodium silicate. Polyhydroxyacrylate compounds are possible stabilizing agents.
- the amount of alkaline agent used is preferably from 0.5% to 10% by weight, preferably from 1% to 6% by weight, preferably from 1.4% to 4% by weight, in particular from 1% to 6% to 2.5% by weight, relative to the weight of dry mechanical pulp.
- the bleaching composition may also comprise a chelating agent as defined above, especially if the chelation step is absent or has resulted in incomplete chelation.
- the bleaching composition can be prepared separately and then brought into contact with the mechanical paper pulp, but it can also be prepared directly in contact with the mechanical pulp. In this second case, the various compounds of the bleaching composition are successively directly added to the mechanical pulp.
- the duration of the bleaching step varies depending on the type of agent used.
- this duration is preferably from 10 minutes to 8 hours, preferably from 30 minutes to 6 hours, more preferably from 2 hours to 4 hours.
- the bleaching step is carried out at a temperature of preferably 4 ° C to 95 ° C, preferably 25 ° C to 85 ° C, more preferably 35 ° C to 80 ° C.
- a temperature of about 70 ° C is particularly suitable.
- the bleaching step can be repeated several times, for example twice.
- a mechanical pulp having a degree of whiteness measured in accordance with ISO 2470-2: 2008, is obtained, greater than or equal to 57%, more preferably greater than or equal to 60 %, ideally greater than or equal to 62% or even greater than or equal to 65%.
- the invention relates to a papermaking process comprising the manufacture of mechanical pulp according to the preceding method and then the use of this mechanical paper pulp to produce paper.
- the mechanical paper stock can be dried and shaped into sheets in a conventional paper machine in the field.
- the mechanical paper stock may also be fed to a dough press machine to be dried and preformed into sheets.
- the leaves can be baled for transfer to a paper mill for possible subsequent processing.
- the tear strength of the paper obtained by virtue of the implementation of the present invention is increased 3%, or even 9%, or even 11%, in relation to a mechanical pulp obtained by refining a wood pre-impregnated with water.
- CSF Canadian Standard Freeness
- the whiteness of the mechanical paper stock is determined by measuring its diffuse blue reflectance factor as defined in ISO 2470-2: 2008.
- the whiteness gain corresponds to the difference between whiteness measured at the end of QP whitening and the whiteness measured at the end of refining.
- the total specific energy of refining is obtained by summing up the values of the electrical consumptions measured for each of the stages preceding the refining and until its exit (for example compression of wood chips, defibration and secondary refining).
- the realized energy saving corresponds to the difference between the specific refining energy of a reference test, carried out in the same conditions that the test X with the difference that it implements an abiotic impregnation composition, and the specific energy of refining of the test X.
- Spruce chips are steamed at atmospheric pressure for 15 minutes and then introduced into a compression screw (ANDRITZ AG Modular Screw Device Impressafiner TM 6 inch), connected to a vat containing the impregnating composition. At the outlet of the screw, the compressed chips are directly expelled into the impregnating composition, where they are allowed to incubate for 1 hour. The impregnating composition is extracted and then the chips are subjected to steam steaming for 5 minutes to stop the enzymatic activity.
- a compression screw ANDRITZ AG Modular Screw Device Impressafiner TM 6 inch
- the chips thus pre-treated are transferred into a mechanical pulping pilot (disc refiner) to be mechanically defibrated and then refined.
- the defibration primary refining
- the secondary refining is carried out at a pressure of 1 bar.
- the gap between the discs is gradually adjusted so as to obtain five mechanical paper pulps of freeness ranging from 250 mL to 50 mL CSF.
- the whiteness of the five mechanical paper stocks is measured according to ISO 2470-2: 2008.
- each obtained TMP mechanical pulp is bleached in a two-step process comprising a chelation step (Q) followed by hydrogen peroxide bleaching (P).
- step Q the consistency of the mechanical paper stock is adjusted to 10% by weight.
- step Q includes putting in contact at a temperature of 60 ° C for 30 minutes, this mechanical paper pulp with 0.4% by weight of diethylene triamine penta acetic acid (DTPA) relative to the total weight of dry mechanical pulp.
- DTPA diethylene triamine penta acetic acid
- Step P comprises contacting, at a temperature of 70 ° C for 120 minutes, this mechanical paper stock with a bleaching composition comprising 3% hydrogen peroxide, 1.9% sodium hydroxide and 2% sodium silicate in percentages by weight relative to the total weight of dry mechanical pulp.
- a bleaching composition comprising 3% hydrogen peroxide, 1.9% sodium hydroxide and 2% sodium silicate in percentages by weight relative to the total weight of dry mechanical pulp.
- the whiteness of the five mechanical paper stocks is measured according to ISO 2470-2: 2008.
- the mechanical paper stocks are then put into sheets in accordance with standard NF EN 5269-1.
- the tear resistance of the sheets is measured according to standard NF EN 21974.
- the specific energy consumption is calculated as described above, namely by summing up the energy consumption of each step of the mechanical pulping process until the end of the refining: 1 st steaming, compression / expulsion, 2 nd parboiling, defibration and subsequent refining.
- the test 3 shows that the invention preserves the paper qualities of the fibers.
- Test 7 shows that, even when the amounts of laccase and DEHA are decreased, the impregnating composition according to the invention makes it possible to reduce the specific energy consumption of refining, to increase the degree of whiteness of the manufactured mechanical pulp and to preserve the strength of the paper which is derived therefrom.
- Test 8 shows that below a certain mediator content, the impregnating composition no longer makes it possible to reduce the specific energy consumption of the refining operation but nevertheless makes it possible to increase the degree of whiteness of the manufactured mechanical pulp and to preserve the strength of the paper which is derived therefrom.
- Poplar wood chips are pulped according to the steaming, pressing and impregnation stages identical to those of tests 1 to 4.
- the impregnation composition used for each of the tests is indicated in the table.
- the impregnating composition of test 9 corresponds to an abiotic composition which serves as a reference.
- the compositions of tests 10 and 11 are in accordance with the invention.
- a second treatment of chips is carried out by adding to the vat 2% by weight of sodium sulfite and 1% by weight of sodium hydroxide, relative to the total weight of dry chips.
- the temperature of the medium is brought to 125 ° C. and the chips are left to impregnate for 15 minutes.
- the impregnated chips are subjected to defibration at a pressure of 2 bar and rotation of disks at 3000 revolutions per minute, then to a second mechanical refining at atmospheric pressure.
- the gap between the discs is gradually adjusted so as to obtain five mechanical paper pulps of freeness ranging from 400 to 100 mL CSF.
- the whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
- each CTMP mechanical pulp obtained is bleached comprising three steps: a chelation step (Q) followed by two successive treatments with hydrogen peroxide (PP).
- step Q the consistency of the mechanical paper stock is adjusted to 10% by weight.
- Step Q comprises contacting, at a temperature of 60 ° C for 30 minutes, this mechanical paper pulp with 0.4% by weight of diethylene triamine pentaacetic acid (DTPA) relative to the total weight of dough dry mechanical paper.
- DTPA diethylene triamine pentaacetic acid
- Step P1 the consistency of the mechanical pulp obtained at the end of step Q is adjusted to 14% by weight.
- Step P1 comprises contacting, at a temperature of 70 ° C for 120 minutes, this mechanical paper stock with a bleaching composition comprising 2.2% hydrogen peroxide, 1.5% hydroxide of sodium, 1% of sodium silicate, 0.075% of magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp.
- a bleaching composition comprising 2.2% hydrogen peroxide, 1.5% hydroxide of sodium, 1% of sodium silicate, 0.075% of magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp.
- the whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
- Step P2 the consistency of the mechanical pulp obtained at the end of step P1 is adjusted to 20% by weight.
- Step P2 comprises contacting, at a temperature of 70 ° C. for 120 minutes, this mechanical paper pulp with a bleaching composition comprising 3.4% hydrogen peroxide, 1.7% sodium hydroxide. , 1.6% sodium silicate, 0.075% magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp.
- a bleaching composition comprising 3.4% hydrogen peroxide, 1.7% sodium hydroxide. , 1.6% sodium silicate, 0.075% magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp.
- the whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
- the specific energy consumption of the process is calculated for each mechanical pulp as described above.
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Description
La présente invention se rapporte à un procédé de fabrication de pâte à papier mécanique. Elle se rapporte également à une composition mise en oeuvre lors de ce procédé et à l'utilisation de cette composition dans un procédé de fabrication de pâte à papier mécanique. Elle se rapporte enfin à un procédé de fabrication de papier.The present invention relates to a method of manufacturing mechanical pulp. It also relates to a composition used in this process and to the use of this composition in a process for manufacturing mechanical pulp. Finally, it relates to a papermaking process.
Les pâtes à papier dites « pâtes mécaniques » ou « pâtes à haut rendement » ou « pâtes de bois » sont obtenues directement à partir du bois par une suite de traitements mécaniques, regroupés généralement sous l'appellation « raffinage » mécanique, effectués au moyen de meules et/ou de raffineurs. La pâte à papier mécanique est ensuite soumise à une phase de blanchiment pouvant comporter un ou plusieurs stades en fonction du degré de blancheur requis.Paper pulps called "mechanical pulp" or "high-performance pulps" or "wood pulp" are obtained directly from the wood by a series of mechanical treatments, generally grouped under the name "mechanical refining", carried out by means of grinding wheels and / or refiners. The mechanical paper stock is then subjected to a bleaching phase which may comprise one or more stages depending on the degree of whiteness required.
L'avantage d'un procédé de fabrication de pâte à papier mécanique est son haut rendement de matière, comparé à un procédé de fabrication de pâte dite « chimique ». En effet, à la différence des procédés de fabrication de pâte chimique dans lesquels la lignine présente dans le bois brut est éliminée en quasi totalité par une cuisson en présence de produits chimiques, environ 90% du bois brut sont conservés dans les pâtes obtenues à l'issue d'un procédé de fabrication de pâte à papier mécanique.The advantage of a mechanical pulping process is its high material yield, compared to a so-called "chemical" pulping process. Indeed, unlike chemical pulping processes in which the lignin present in the raw wood is eliminated almost completely by cooking in the presence of chemicals, about 90% of the raw wood is preserved in the pasta obtained in the pasta. from a process for manufacturing mechanical pulp.
Le raffinage mécanique d'un procédé de fabrication de pâte à papier mécanique comporte typiquement plusieurs étapes de raffinage, telles qu'un raffinage primaire appelé généralement « défibrage », un raffinage secondaire, un raffinage tertiaire, un raffinage des refus de classage, etc. Ces étapes de raffinages procurent des pâtes présentant des degrés de raffinage différents, afin de transformer progressivement le bois en fibres individualisées et permettre ainsi la fabrication de pâte à papier.Mechanical refining of a mechanical pulp manufacturing process typically involves several refining steps, such as primary refining generally referred to as "defibration", secondary refining, tertiary refining, refining of classification rejects, and the like. These refining steps provide pastes with different degrees of refinement, in order to gradually transform the wood into individualized fibers and thus enable the manufacture of paper pulp.
Le raffinage mécanique présente l'inconvénient d'être fortement consommateur d'énergie, typiquement de 1500 à 3000 kWh par tonne de pâte à papier mécanique produite. Cette énergie représente d'une part un coût important et d'autre part, elle est susceptible d'abîmer les fibres du bois. Aussi différentes voies ont-elles été envisagées pour réduire l'énergie à apporter.Mechanical refining has the disadvantage of being a major consumer of energy, typically from 1500 to 3000 kWh per ton of mechanical pulp produced. This energy represents on the one hand a significant cost and on the other hand, it is likely to damage the wood fibers. Also different ways have been considered to reduce the energy to bring.
Ainsi, le document
Le document
Par ailleurs, il s'est développé un intérêt particulier pour des traitements enzymatiques du bois dans les procédés de fabrication de pâte à papier mécanique, du fait de leur faible impact environnemental.In addition, there has been a particular interest in enzymatic wood treatments in mechanical pulping processes because of their low environmental impact.
On connaît ainsi le document
Les documents
Le document
L'optimisation de l'activité enzymatique des laccases a par ailleurs été étudiée dans le document
Ainsi, les méthodes et les produits utilisés dans l'état de la technique ne donnent pas entière satisfaction.Thus, the methods and products used in the state of the art are not entirely satisfactory.
Il existe en particulier toujours un besoin de réduire la demande énergétique des procédés de fabrication de pâte à papier mécanique et de garantir pour autant une pâte à papier mécanique aux qualités papetières équivalentes ou améliorées, par rapport à celles obtenues par les méthodes connues. Il existe également un besoin pour une pâte à papier mécanique présentant un degré de blancheur supérieur à l'issue du raffinage et/ou développant une meilleure aptitude au blanchiment que celles obtenues par les procédés connus. Il existe enfin un besoin de réduire la quantité de produits chimiques à mettre en oeuvre pour blanchir une pâte à papier mécanique tout en garantissant un degré de blancheur équivalent ou amélioré, par rapport aux pâtes à papier mécaniques obtenues avec les méthodes de l'état de la technique.In particular, there is still a need to reduce the energy demand of mechanical pulp manufacturing processes and to guarantee a mechanical paper pulp with equivalent or improved paper qualities, compared to those obtained by known methods. There is also a need for a mechanical pulp having a higher degree of whiteness at the end of refining and / or developing a better bleaching ability than those obtained by known methods. Finally, there is a need to reduce the amount of chemicals to be used for bleaching a mechanical pulp while maintaining an equivalent or improved degree of whiteness compared to mechanical paper pulps obtained with the methods of the state of the art. the technique.
Aussi, la présente invention a pour objet un procédé de fabrication d'une pâte à papier mécanique permettant de remédier aux inconvénients ci-dessus.Also, the present invention relates to a method of manufacturing a mechanical paper stock to overcome the above drawbacks.
De façon plus précise, l'invention concerne en premier lieu un procédé de fabrication d'une pâte à papier mécanique comprenant au moins :
- une étape d'imprégnation d'un bois brut comprenant la mise en contact du bois brut avec une composition d'imprégnation comprenant, relativement à son poids total, de 0,01% à 10% en poids d'une solution de laccase à 1000 LAMU/mL de ladite solution et de 0,1% à 10% en poids d'un médiateur de formule (I) :
ladite composition d'imprégnation étant utilisée à raison de 0,1 à 12 L/kg du bois brut à imprégner ; et - une étape de raffinage mécanique du bois imprégné, de sorte à obtenir une pâte à papier mécanique.
- a stage of impregnation of a raw wood comprising contacting the raw wood with an impregnating composition comprising, relative to its total weight, from 0.01% to 10% by weight of a laccase solution to 1000 LAMU / mL of said solution and 0.1% to 10% by weight of a mediator of formula (I):
said impregnating composition being used in a proportion of 0.1 to 12 L / kg of the raw wood to be impregnated; and - a mechanical refining step of the impregnated wood, so as to obtain a mechanical pulp.
Parmi les médiateurs de formule (I), on préfère encore ceux pour lesquels au moins un de R1 et R2 est différent de H. On préfère encore davantage ceux pour lesquels R1 = R2 et représentent chacun un radical alkyle en C1-C4. Un exemple particulièrement préféré étant la N,N-diéthylhydroxylamine.Among the mediators of formula (I), those for which at least one of R1 and R2 is different from H are furthermore preferred. Those for which R1 = R2 and each represent a C1-C4 alkyl radical are more preferred. A particularly preferred example being N, N-diethylhydroxylamine.
L'invention se rapporte également à la composition d'imprégnation mise en oeuvre dans ce procédé.The invention also relates to the impregnating composition used in this process.
L'invention a aussi pour objet l'utilisation de ladite composition d'imprégnation dans un procédé de fabrication de pâte à papier mécanique pour abaisser la consommation énergétique dudit procédé.The invention also relates to the use of said impregnating composition in a mechanical pulp manufacturing process for lowering the energy consumption of said process.
L'invention a encore pour objet l'utilisation de ladite composition d'imprégnation dans un procédé de fabrication de pâte à papier mécanique pour augmenter la blancheur de ladite pâte.The invention further relates to the use of said impregnating composition in a process for manufacturing mechanical pulp to increase the whiteness of said paste.
L'invention a aussi pour objet l'utilisation de ladite composition d'imprégnation dans un procédé de fabrication de pâte à papier mécanique comprenant une étape de raffinage mécanique, ladite composition d'imprégnation étant utilisée avant l'étape de raffinage mécanique.The invention also relates to the use of said impregnating composition in a process for manufacturing mechanical pulp comprising a mechanical refining step, said impregnating composition being used before the mechanical refining step.
L'invention a enfin pour objet un procédé de fabrication de papier, comprenant la fabrication d'une pâte à papier mécanique selon le procédé ci-dessus, ainsi que l'utilisation de cette pâte à papier mécanique pour produire du papier.Finally, the subject of the invention is a papermaking process, comprising the manufacture of a mechanical paper pulp according to the above method, as well as the use of this mechanical paper pulp to produce paper.
La présente invention permet de surmonter les inconvénients de l'état de la technique. En particulier, elle fournit un procédé de fabrication de pâte à papier mécanique plus économique en énergie et qui garantit une pâte et un papier aux qualités papetières équivalentes ou améliorées par rapport aux procédés connus. Elle fournit également une pâte à papier mécanique présentant un degré de blancheur supérieur à l'issue du raffinage et/ou développant une meilleure aptitude au blanchiment par rapport aux pâtes à papier mécaniques obtenues avec les procédés connus. L'invention permet en outre de réduire la quantité de produits chimiques à mettre en oeuvre pour blanchir la pâte à papier mécanique, tout en garantissant un degré de blancheur à l'issue du blanchiment au moins équivalent voire supérieur à celui des pâtes à papier mécaniques produites avec les procédés connus. Ceci est accompli grâce à une étape d'imprégnation de bois avec une composition d'imprégnation particulière, préalablement à son raffinage.The present invention overcomes the disadvantages of the state of the art. In particular, it provides a method of manufacturing mechanical pulp more energy-efficient and which guarantees a pulp and paper paper qualities equivalent or improved over known methods. It also provides a mechanical pulp having a higher degree of whiteness at the end of the refining and / or developing a better bleaching ability compared to mechanical pulps obtained with the known methods. The invention also makes it possible to reduce the quantity of chemicals to be used for bleaching the mechanical paper pulp, while guaranteeing a degree of whiteness at the end of bleaching at least equivalent to or even greater than that of mechanical paper pulps. produced with the known methods. This is accomplished by a wood impregnation step with a particular impregnating composition prior to refining.
En particulier, la composition selon l'invention oxyde les unités phénoliques et non phénoliques de la lignine, ce qui entraîne une fragilisation des liaisons entre les fibres. La Demanderesse a en particulier mis au point une composition d'imprégnation qui agit spécifiquement sur la paroi cellulaire des fibres, permettant de diminuer la cohésion entre les fibres tout en préservant celles-ci. Aussi, lorsque la composition de l'invention est utilisée sur un bois avant son raffinage, elle permet de diminuer l'énergie qu'il serait nécessaire de fournir pendant le raffinage pour séparer les fibres du bois si aucun prétraitement n'était effectué ou si une méthode de l'état de la technique était mise en oeuvre à sa place. En outre, la longueur des fibres issues du bois de départ et leur résistance sont préservées dans la pâte à papier mécanique fabriquée et dans le papier qui en est issu.In particular, the composition according to the invention oxidizes the phenolic and non-phenolic units of the lignin, which leads to weakening of the bonds between the fibers. The Applicant has in particular developed an impregnating composition that acts specifically on the cell wall of the fibers, to reduce the cohesion between the fibers while preserving them. Also, when the composition of the invention is used on a wood before refining, it reduces the energy that it would be necessary to provide during the refining to separate the wood fibers if no pretreatment was performed or if a method of the state of the art was implemented in its place. In addition, the length of the fibers from the starting wood and their strength are preserved in the manufactured mechanical pulp and in the paper that is derived therefrom.
Enfin, à la différence des compositions proposées par l'état de la technique, la composition d'imprégnation selon l'invention est peu onéreuse, disponible en large quantité et de moindre toxicité pour l'environnement.Finally, unlike the compositions proposed by the state of the art, the impregnating composition according to the invention is inexpensive, available in large quantities and less toxic to the environment.
Par « médiateur », selon l'invention, on entend un composé qui améliore la capacité d'une enzyme à oxyder un bois.By "mediator" according to the invention is meant a compound which improves the ability of an enzyme to oxidize a wood.
Par « bois », on entend l'ensemble des tissus résistants secondaires (de soutien, de conduction, et de mise en réserve) qui forment les troncs, branches et racines des plantes ligneuses, au sens de la norme NF B 50-003.By "wood" is meant all secondary resistant tissues (support, conduction, and storage) which form the trunks, branches and roots of woody plants, within the meaning of standard NF B 50-003.
Par bois « brut » on entend l'état d'un bois avant son traitement avec une composition d'imprégnation selon l'invention et par bois « imprégné » on entend l'état d'un bois après son traitement avec une composition d'imprégnation selon l'invention.By "raw" wood is meant the state of a wood before its treatment with an impregnating composition according to the invention and "impregnated" wood means the state of a wood after its treatment with an impregnating composition according to the invention.
Sauf mention contraire, les pourcentages de matière mentionnés sont des pourcentages en poids.Unless otherwise stated, the percentages of material mentioned are percentages by weight.
Sauf mention contraire, les pourcentages en poids de bois sont donnés en poids de bois sec. Par « bois sec » on entend que le bois a été séché au four conformément à la norme ISO 638:2008 à savoir à une température allant de 103°C à 107°C, pendant une durée d'au moins 30 minutes et ne dépassant pas 16 heures à pression atmosphérique.Unless otherwise stated, percentages by weight of wood are given by weight of dry wood. "Dry wood" means that the wood has been kiln-dried in accordance with ISO 638: 2008, ie at a temperature of between 103 ° C and 107 ° C, for a period of not less than 30 minutes and not exceeding not 16 hours at atmospheric pressure.
La « consistance » de la pâte à papier mécanique désigne la concentration en pâte telle que définie dans la Norme ISO 4119 de juin 1996. C'est le rapport de la masse sèche de matière pouvant être filtrée d'un échantillon de pâte en suspension, à la masse de l'échantillon non filtré, l'essai étant effectué conformément à ladite Norme internationale. La concentration en pâte y est exprimée en pourcentage en masse.The "consistency" of mechanical pulp refers to the pulp concentration as defined in ISO Standard 4119 of June 1996. This is the ratio of the dry mass of filterable material to a suspended pulp sample, to the mass of the unfiltered sample, the test being carried out in accordance with said International Standard. The paste concentration is expressed as a percentage by mass.
Sauf mention contraire, les pourcentages en poids de pâte à papier mécanique sont donnés en poids de pâte à papier mécanique sèche. Par « pâte à papier mécanique sèche » on entend la masse sèche de matière d'un échantillon de pâte en suspension telle que définie dans la Norme ISO 4119 susvisée, étant mesurée après filtrage et séchage conformément à ladite Norme.Unless otherwise stated, percentages by weight of mechanical pulp are given by weight of dry mechanical pulp. By "dry mechanical paper pulp" is meant the dry mass of material of a suspended pulp sample as defined in the abovementioned ISO standard 4119, being measured after filtering and drying in accordance with said standard.
Sauf s'il en est disposé autrement, les mesures sont effectuées à pression atmosphérique.Unless otherwise specified, measurements are made at atmospheric pressure.
Lorsqu'il est fait référence à des intervalles, les expressions du type « allant de...à » incluent les bornes de l'intervalle. A l'inverse, les expressions du type « compris entre...et... » excluent les bornes de l'intervalle.When referring to intervals, expressions of the type "from ... to" include the bounds of the range. On the other hand, expressions of the type "between ... and ..." exclude the bounds of the interval.
L'invention est maintenant décrite plus en détail et de façon non limitative dans la description qui suit.The invention is now described in more detail and without limitation in the description which follows.
De façon schématique, le procédé de fabrication de pâte à papier mécanique selon l'invention comprend au moins :
- une étape d'imprégnation d'un bois brut, comprenant la mise en contact du bois brut avec une composition d'imprégnation selon l'invention, de sorte à obtenir un bois imprégné,
- une étape de raffinage mécanique du bois imprégné, de sorte à obtenir une pâte à papier mécanique.
- a step of impregnating a raw wood, comprising contacting the raw wood with an impregnating composition according to the invention, so as to obtain an impregnated wood,
- a mechanical refining step of the impregnated wood, so as to obtain a mechanical pulp.
De façon plus détaillée, le procédé de fabrication de pâte à papier mécanique selon l'invention comprend, de préférence dans l'ordre, les étapes suivantes :
- éventuellement un étuvage à la vapeur d'eau d'un bois brut,
- éventuellement un pressage d'un bois brut,
- au moins une étape d'imprégnation d'un bois brut avec une composition d'imprégnation selon l'invention, pour obtenir un bois imprégné,
- éventuellement un étuvage à la vapeur d'eau du bois imprégné,
- au moins une étape de raffinage mécanique du bois imprégné, pour obtenir une pâte à papier mécanique,
- éventuellement une étape de chélation de la pâte à papier mécanique,
- éventuellement un blanchiment de la pâte à papier mécanique.
- possibly a steaming of a raw wood,
- possibly a pressing of a raw wood,
- at least one step of impregnating a raw wood with an impregnating composition according to the invention, to obtain an impregnated wood,
- optionally steaming the impregnated wood,
- at least one step of mechanical refining of the impregnated wood, to obtain a mechanical paper pulp,
- optionally a step of chelating the mechanical pulp,
- possibly a bleaching of the mechanical pulp.
On utilise comme matière première un bois brut.Raw wood is used as raw material.
Selon un mode de réalisation, le bois brut est choisi parmi les bois de résineux, les bois de feuillus ou leurs mélanges. Comme bois de résineux appropriés, on peut citer le Douglas, l'épicéa, le pin d'Alep, le pin maritime, le pin noir, le pin Sylvestre, le pin Taeda, le cèdre rouge (Thulya plicata) ou leurs mélanges. Comme bois de feuillus appropriés, on peut citer le peuplier, le tremble, le bouleau, l'érable, le chêne, l'eucalyptus, l'acacia, le hêtre, le châtaigner, le charme, l'aulne ou leurs mélanges. De préférence, on utilise de l'épicea, du peuplier, de l'eucalyptus ou un mélange de ceux-ci.According to one embodiment, the raw wood is selected from softwoods, hardwoods or mixtures thereof. Suitable softwoods include Douglas fir, Spruce, Aleppo pine, Maritime pine, Black pine, Scots pine, Taeda pine, Red cedar ( Thulya plicata ) or mixtures thereof. Suitable hardwoods include poplar, aspen, birch, maple, oak, eucalyptus, acacia, beech, chestnut, hornbeam, alder or mixtures thereof. Preferably, spruce, poplar, eucalyptus or a mixture thereof is used.
Selon un mode de réalisation, pour fabriquer une pâte à papier chimicothermomécanique (CTMP), le bois brut peut être choisi parmi les bois de résineux tels que ceux précités, les bois de feuillus tels que ceux précités, ou encore le bambou, le chanvre, la paille de céréales, par exemple la paille de blé ou la paille de riz, le coton ou leurs mélanges.According to one embodiment, in order to manufacture a chemomercomechanical pulp (CTMP), the raw wood may be chosen from softwoods such as those mentioned above, hardwoods such as those mentioned above, or bamboo, hemp, cereal straw, for example wheat straw or rice straw, cotton or mixtures thereof.
Selon un mode de réalisation préféré, le bois brut se trouve sous la forme de copeaux. Le terme « copeaux » est employé au sens conventionnel pour l'homme de l'art. Il désigne des particules de bois pouvant être obtenues par tout procédé industriel classiquement utilisé dans le domaine de la pâte à papier mécanique. La taille des copeaux est typiquement distribuable selon la norme SCAN-CM 40:01. Cette forme facilite notamment le traitement d'imprégnation ultérieur du bois et en améliore l'efficacité. Les copeaux peuvent typiquement être obtenus à partir de rondins de bois brut écorcés et coupés ou de sous-produits résiduaires de l'industrie du bois.According to a preferred embodiment, the raw wood is in the form of chips. The term "chips" is used in the conventional sense for those skilled in the art. It designates wood particles that can be obtained by any industrial process conventionally used in the field of mechanical pulp. The chip size is typically distributable according to the standard SCAN-CM 40:01. This form facilitates the subsequent impregnation treatment of the wood and improves its effectiveness. The chips can typically be obtained from debarked and cut raw logs or residual by-products from the wood industry.
Selon un mode de réalisation, le bois subit, avant ou après l'étape d'imprégnation, de préférence avant l'étape d'imprégnation, au moins un prétraitement choisi parmi un prétraitement thermique, un prétraitement chimique, un prétraitement mécanique ou une combinaison de ceux-ci. Comme prétraitement thermique approprié, on peut citer un étuvage à la vapeur d'eau, un traitement à l'eau chaude ou une combinaison de ceux-ci. Comme prétraitement chimique approprié, on peut citer un traitement d'imprégnation du bois avec au moins un agent chimique choisi parmi un acide, une base, un oxydant, un réducteur, un chélateur, un stabilisant, un surfactant, une enzyme ou leurs mélanges. Comme prétraitement mécanique approprié, on peut citer un pressage.According to one embodiment, the wood undergoes, before or after the impregnation step, preferably before the impregnation step, at least one pretreatment chosen from a heat pretreatment, a chemical pretreatment, a mechanical pretreatment or a combination of these. Suitable heat pretreatment include steam steaming, hot water treatment or a combination thereof. As a suitable chemical pretreatment, there may be mentioned a wood impregnation treatment with at least one chemical agent chosen from an acid, a base, an oxidant, a reducing agent, a chelator, a stabilizer, a surfactant, an enzyme or their mixtures. As suitable mechanical pretreatment, there may be mentioned a pressing.
Selon un mode de réalisation, le bois subit, avant ou après l'étape d'imprégnation, de préférence avant l'étape d'imprégnation, un étuvage à la vapeur d'eau, ce qui permet d'homogénéiser la siccité du bois. L'étuvage comprend la mise en contact du bois avec de la vapeur d'eau. L'étuvage est de préférence mis en oeuvre à pression atmosphérique. L'étuvage a de préférence une durée allant de 5 à 30 minutes, de préférence encore de 10 à 20 minutes.According to one embodiment, the wood undergoes, before or after the impregnation step, preferably before the impregnation step, steam steaming, which makes it possible to homogenize the dryness of the wood. Stoving includes contacting the wood with water vapor. Steaming is preferably carried out at atmospheric pressure. Stoving preferably has a duration of from 5 to 30 minutes, more preferably from 10 to 20 minutes.
Selon un mode de réalisation, le bois brut subit, avant ou après l'étape d'imprégnation, de préférence avant l'étape d'imprégnation, un pressage. Le pressage peut être réalisé à l'aide de tout moyen connu de l'homme du métier, de préférence à l'aide d'un dispositif de compression tel qu'une presse à vis ou une presse à cylindre.According to one embodiment, the raw wood undergoes, before or after the impregnation step, preferably before the impregnation step, a pressing. The pressing can be carried out using any means known to those skilled in the art, preferably with the aid of a compression device such as a screw press or a cylinder press.
Les modes de réalisations précités peuvent avantageusement être combinés entre eux : selon un mode de réalisation préféré, le bois brut se trouve initialement sous la forme de copeaux et les copeaux subissent un étuvage à la vapeur d'eau tel que défini ci-dessus ; selon un autre mode de réalisation préféré, le bois brut subit, avant l'étape d'imprégnation, un étuvage à la vapeur d'eau suivi d'un pressage tels que définis ci-dessus.The aforementioned embodiments may advantageously be combined with one another: according to a preferred embodiment, the raw wood is initially in the form of chips and the chips are steam-steamed as defined above; according to another preferred embodiment, the raw wood undergoes, before the impregnation step, a steam steaming followed by pressing as defined above.
Selon un mode de réalisation particulier, le bois ne subit pas de prétraitement chimique avant l'étape d'imprégnation, notamment pas de lavage acide ou de traitement de chélation.According to a particular embodiment, the wood does not undergo chemical pretreatment before the impregnation step, in particular no acid wash or chelation treatment.
Les divers prétraitements précités peuvent être mis en oeuvre avant ou après l'étape d'imprégnation. Ils peuvent en outre être répétés si besoin est. Par exemple, on peut mettre en oeuvre un de ces prétraitements avant l'étape d'imprégnation, effectuer l'étape d'imprégnation puis réitérer ledit prétraitement après l'étape d'imprégnation.The various pretreatments mentioned above may be used before or after the impregnation step. They can be repeated if needed. For example, one of these pretreatments can be used before the impregnation step, the impregnation step can be carried out and then the said pretreatment can be repeated after the impregnation step.
Le procédé de fabrication selon l'invention comprend une étape d'imprégnation d'un bois brut, comprenant la mise en contact du bois brut avec une composition d'imprégnation selon l'invention de sorte à obtenir un bois imprégné. Ladite composition d'imprégnation comprend au moins une enzyme laccase et un médiateur de formule particulière. La composition d'imprégnation selon l'invention comprend ainsi un médiateur de formule (I) :
De préférence encore, R1 et R2 sont des chaînes alkyle identiques ou différentes en C1 à C4. De préférence toujours, R1 et R2 sont des chaînes alkyle identiques de formule C2H5 : le médiateur préféré est ainsi la diéthyl hydroxylamine (DEHA).More preferably, R1 and R2 are identical or different C1 to C4 alkyl chains. More preferably, R1 and R2 are identical alkyl chains of the formula C2H5: the preferred mediator is thus diethyl hydroxylamine (DEHA).
Le médiateur peut être présent dans la composition d'imprégnation sous forme pure, en solution dans l'eau ou sous la forme de l'un de ses sels.The mediator may be present in the impregnating composition in pure form, in solution in water or in the form of one of its salts.
La teneur en médiateur dans la composition d'imprégnation va de préférence de 0,1% à 10% en poids, de préférence de 0,15% à 4,5% en poids, de préférence de 0,19% à 4% en poids, de préférence de 0,19% à 3% en poids, voire de 0,23% à 2% en poids relativement au poids total de la composition d'imprégnation.The mediator content in the impregnating composition is preferably from 0.1% to 10% by weight, preferably from 0.15% to 4.5% by weight, preferably from 0.19% to 4% by weight. weight, preferably from 0.19% to 3% by weight, or even from 0.23% to 2% by weight relative to the total weight of the impregnating composition.
La teneur en médiateur, relativement à la masse de bois brut sec à traiter, va de préférence de 0,1% à 10%, de 0,2% à 10%, de 0,2% à 5%, de préférence encore de 0,2% à 0,5%, voire de 0,25% à 0,5%, en poids de bois sec.The mediator content, relative to the dry raw wood mass to be treated, is preferably from 0.1% to 10%, from 0.2% to 10%, from 0.2% to 5%, more preferably from 0.2% to 0.5%, or even 0.25% to 0.5%, by weight of dry wood.
L'enzyme laccase peut être choisie dans la classe EC 1.10.3.2 de la nomenclature des enzymes. La myceliophthora laccase est particulièrement préférée.The enzyme laccase may be selected from class EC 1.10.3.2 of the Enzyme Nomenclature. Myceliophthora laccase is particularly preferred.
L'enzyme laccase peut être sous forme d'extrait brut, sous forme purifiée ou semi-purifiée.The laccase enzyme may be in the form of a crude extract, in purified or semi-purified form.
La teneur en solution de laccase à 1000 LAMU/mL, relativement à la masse de bois brut sec à traiter, va de préférence de 0,1 à 10 L/t, de 1 à 5 L/t, de préférence encore de 1 à 2 L/t du bois brut sec.The solution content of the laccase at 1000 LAMU / ml, relative to the dry raw wood mass to be treated, is preferably from 0.1 to 10 L / t, from 1 to 5 L / t, more preferably from 1 to 2 L / t of dry raw wood.
La teneur en solution de laccase à 1000 LAMU/mL, dans la composition d'imprégnation, va de préférence de 0,01% à 10% en poids, de 0,05% à 5% en poids, de 0,05% à 1% en poids, en particulier de 0,09% à 0,2 % en poids, relativement au poids total de la composition d'imprégnation.The solution content of 1000 LAMU / ml laccase in the impregnating composition is preferably from 0.01% to 10% by weight, from 0.05% to 5% by weight. weight, from 0.05% to 1% by weight, in particular from 0.09% to 0.2% by weight, relative to the total weight of the impregnating composition.
La composition d'imprégnation selon l'invention peut en outre comprendre un ou plusieurs additifs usuels pour l'homme du métier, à condition que leur présence n'amoindrisse pas l'efficacité de la composition. De tels additifs peuvent notamment être choisis parmi : une enzyme autre que la laccase, un oxydant, un réducteur, un acide, une base, un agent chélateur, un stabilisant, un surfactant, leurs combinaisons. Lorsque présent, la teneur en additif total dans la composition d'imprégnation est de préférence inférieure à 3% en poids, en particulier inférieure à 2% en poids relativement au poids total de la composition. Selon un mode de réalisation, la composition d'imprégnation ne comprend pas d'additif.The impregnating composition according to the invention may further comprise one or more additives customary to the person skilled in the art, provided that their presence does not detract from the effectiveness of the composition. Such additives may especially be chosen from: an enzyme other than laccase, an oxidant, a reducing agent, an acid, a base, a chelating agent, a stabilizer, a surfactant, their combinations. When present, the total additive content in the impregnating composition is preferably less than 3% by weight, in particular less than 2% by weight, relative to the total weight of the composition. According to one embodiment, the impregnating composition does not comprise an additive.
Selon un mode de réalisation, la composition d'imprégnation est une solution aqueuse. La teneur en eau de la composition correspond alors au complément à 100% en poids de la somme des teneurs en médiateur, en enzyme et en additifs éventuels.According to one embodiment, the impregnating composition is an aqueous solution. The water content of the composition then corresponds to the complement at 100% by weight of the sum of the contents of mediator, enzyme and possible additives.
Selon un mode de réalisation, on utilise la composition d'imprégnation à raison de 0,1 à 12 L/kg du bois brut sec à imprégner, de préférence à raison de 1 à 10 L/kg du bois brut à imprégner. L'excès de composition d'imprégnation peut avantageusement être recyclé pour effectuer une nouvelle étape d'imprégnation sur un autre bois brut ou sur le bois imprégné.According to one embodiment, the impregnating composition is used at a rate of 0.1 to 12 L / kg of dry raw wood to be impregnated, preferably at a rate of 1 to 10 L / kg of the raw wood to be impregnated. The excess impregnating composition may advantageously be recycled to perform a new impregnation step on another raw wood or on the impregnated wood.
Selon un mode de réalisation, la mise en contact du bois brut avec la composition d'imprégnation comprend (voire consiste en) une vaporisation de la composition d'imprégnation sur le bois brut ou une immersion du bois brut dans un bain de composition d'imprégnation.According to one embodiment, the contacting of the raw wood with the impregnating composition comprises (or even consists of) a vaporization of the impregnating composition on the raw wood or an immersion of the raw wood in a composition bath. impregnation.
Selon un mode de réalisation particulier, le bois brut est immergé dans la composition d'imprégnation pendant une durée suffisante pour permettre une imprégnation du bois en composition d'imprégnation, puis le bois est retiré de la composition et laissé à incuber pendant une durée suffisante pour permettre à l'enzyme d'agir sur le bois. En variante, le bois brut est immergé dans la composition d'imprégnation et y est laissé à incuber pendant une durée suffisante pour permettre à l'enzyme d'agir sur le bois. L'incubation peut être mise en oeuvre dans tout dispositif adapté connu de l'homme du métier, par exemple dans un cuvier de stockage.According to a particular embodiment, the raw wood is immersed in the impregnating composition for a time sufficient to allow impregnation of the wood impregnating composition, then the wood is removed from the composition and incubated for a sufficient period of time to allow the enzyme to act on the wood. Alternatively, the raw wood is immersed in the impregnating composition and is allowed to incubate for a time sufficient to allow the enzyme to act on the wood. Incubation may be carried out in any suitable device known to those skilled in the art, for example in a storage cabinet.
Selon un mode de réalisation préférée, la mise en contact du bois brut avec la composition d'imprégnation est mise en oeuvre par projection de copeaux de bois brut, compressés depuis une vis de compression directement dans un bain de composition d'imprégnation. Ceci permet une absorption optimale des copeaux (les copeaux aspirant la composition à la manière d'une éponge) et favorise l'action de la composition au coeur des fibres du bois.According to a preferred embodiment, the contacting of the raw wood with the impregnating composition is carried out by spraying raw wood chips, compressed from a compression screw directly into a bath of impregnating composition. This allows optimal chip absorption (the chips sucking the composition in the manner of a sponge) and promotes the action of the composition in the heart of the wood fibers.
La mise en contact du bois brut avec la composition d'imprégnation est de préférence mise en oeuvre pendant une durée allant de 5 minutes à 240 minutes, de 25 minutes à 180 minutes, de 45 minutes à 120 minutes, de préférence encore de 55 min à 65 min. La composition d'imprégnation est de préférence mise en oeuvre à une température allant de 35 à 80°C, de 40 à 70°C, plus particulièrement de 45 à 55°C. Elle est de préférence mise en oeuvre à un pH allant de 3 à 11, de 4 à 7, de préférence encore de 4,5 à 5,5. De telles conditions sont avantageuses pour optimiser l'efficacité de la composition selon l'invention.The contacting of the raw wood with the impregnating composition is preferably carried out for a duration ranging from 5 minutes to 240 minutes, from 25 minutes to 180 minutes, from 45 minutes to 120 minutes, more preferably 55 minutes. at 65 min. The impregnating composition is preferably carried out at a temperature of 35 to 80 ° C, 40 to 70 ° C, more preferably 45 to 55 ° C. It is preferably carried out at a pH ranging from 3 to 11, from 4 to 7, more preferably from 4.5 to 5.5. Such conditions are advantageous for optimizing the effectiveness of the composition according to the invention.
L'étape d'imprégnation peut être stoppée par un étuvage (mise en contact du bois imprégné avec de la vapeur d'eau) ou un lavage à l'eau, afin de stopper l'activité de l'enzyme. La durée de l'étuvage ou du lavage à l'eau va de préférence de 1 à 10 minutes, de préférence encore de 3 à 7 minutes. De manière préférée, on effectue un étuvage à la vapeur d'eau à pression atmosphérique.The impregnation stage can be stopped by steaming (contacting the impregnated wood with steam) or washing with water, in order to stop the activity of the enzyme. The duration of steaming or washing with water is preferably from 1 to 10 minutes, more preferably from 3 to 7 minutes. Preferably, steaming is carried out at atmospheric pressure.
De manière avantageuse, on peut répéter l'étape d'imprégnation plusieurs fois, en particulier deux à quatre fois. Les différents modes de réalisation précités peuvent aussi être combinés entre eux. Enfin, il faut noter que la composition d'imprégnation peut être préparée séparément puis mise en contact avec le bois brut, comme expliqué ci-dessus, mais elle peut également être préparée directement au contact du bois brut. Dans ce cas, les différents composés de la composition d'imprégnation sont ajoutés successivement et directement au bois brut.Advantageously, the impregnation step may be repeated several times, in particular two to four times. The various embodiments mentioned above can also be combined with each other. Finally, it should be noted that the impregnating composition can be prepared separately and then brought into contact with the raw wood, as explained above, but it can also be prepared directly in contact with the raw wood. In this case, the various compounds of the impregnating composition are added successively and directly to the raw wood.
Outre l'imprégnation, le bois peut être soumis à un traitement complémentaire, dit post-traitement. Ce post-traitement comprend la mise en contact avec une composition chimique comprenant un agent alcalin et un agent réducteur. Ce post-traitement est avantageux pour ramollir la lignine et développer les caractéristiques mécaniques des fibres. Il est en particulier avantageux lorsque l'on souhaite fabriquer une pâte à papier chimicothermomécanique (CTMP).In addition to the impregnation, the wood can be subjected to a complementary treatment, called post-treatment. This post-treatment comprises contacting with a chemical composition comprising an alkaline agent and a reducing agent. This post-treatment is advantageous for softening the lignin and developing the mechanical characteristics of the fibers. In particular, it is advantageous when it is desired to manufacture a chemo-thermomechanical pulp (CTMP).
Cette étape est de préférence mise en oeuvre après l'étape d'imprégnation pour éviter une potentielle inhibition des enzymes de la composition d'imprégnation. Elle peut être mise en oeuvre avant ou après l'étape de raffinage. Elle est de préférence mise en oeuvre entre l'étape d'imprégnation et l'étape de raffinage, ce qui permet d'augmenter l'économie d'énergie du raffinage.This step is preferably carried out after the impregnation step to avoid a potential inhibition of the enzymes of the impregnating composition. It can be implemented before or after the refining step. It is preferably carried out between the impregnation stage and the refining stage, which makes it possible to increase the energy saving of the refining.
Selon un mode de réalisation, la mise en contact du bois avec la composition chimique comprend une vaporisation de ladite composition sur le bois ou une immersion du bois dans un bain de ladite composition.According to one embodiment, the contacting of the wood with the chemical composition comprises a vaporization of said composition on the wood or immersion of the wood in a bath of said composition.
Selon un mode de réalisation, l'agent alcalin est choisi parmi l'hydroxyde de sodium, l'hydroxyde de magnésium, l'hydroxyde de potassium, le carbonate de sodium, le bicarbonate de sodium, le silicate de sodium, ou leurs mélanges. De manière préférée, l'agent alcalin est choisi parmi le silicate de sodium, l'hydroxyde de sodium ou leur mélange.According to one embodiment, the alkaline agent is selected from sodium hydroxide, magnesium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, sodium silicate, or mixtures thereof. Preferably, the alkaline agent is chosen from sodium silicate, sodium hydroxide or their mixture.
Selon un mode de réalisation, l'agent réducteur est choisi parmi le sulfite de sodium Na2S2O3, le bisulfite de sodium NaHSO3 ou leur mélange.According to one embodiment, the reducing agent is chosen from sodium sulphite Na 2 S 2 O 3 , sodium bisulfite NaHSO 3 or their mixture.
Selon un mode de réalisation, l'agent alcalin est présent en une teneur allant de 0,1% à 20% en poids, de préférence de 1% à 10% en poids, relativement au poids de bois.According to one embodiment, the alkaline agent is present in a content ranging from 0.1% to 20% by weight, preferably from 1% to 10% by weight, relative to the weight of wood.
Selon un mode de réalisation, l'agent réducteur est présent en une teneur allant de 0,1% à 30% en poids, de préférence de 1% à 20% en poids, relativement au poids de bois.According to one embodiment, the reducing agent is present in a content ranging from 0.1% to 30% by weight, preferably from 1% to 20% by weight, relative to the weight of wood.
L'étape de post-traitement chimique est de préférence mise en oeuvre à une température allant de 10°C à 150°C, en particulier de 60°C à 120°C. Elle est de préférence mise en oeuvre pendant une durée allant de 1 minute à 120 minutes, de préférence de 1 à 60 minutes.The chemical post-treatment step is preferably carried out at a temperature of from 10 ° C to 150 ° C, in particular from 60 ° C to 120 ° C. It is preferably carried out for a time ranging from 1 minute to 120 minutes, preferably from 1 to 60 minutes.
L'étape de post-traitement chimique peut être terminée par tout moyen permettant de stopper la réaction des agents chimiques sur le bois, par exemple par un lavage à l'eau.The chemical post-treatment step may be terminated by any means for stopping the reaction of the chemical agents on the wood, for example by washing with water.
De manière avantageuse, l'étape de post-traitement chimique peut être répétée plusieurs fois, en particulier deux fois à quatre fois, ce qui permet de renforcer encore les aptitudes papetières des fibres.Advantageously, the chemical post-treatment step can be repeated several times, in particular twice to four times, which makes it possible to further reinforce the papermaking capabilities of the fibers.
Après l'étape d'imprégnation (et l'étape de post-traitement chimique éventuelle), on procède à un raffinage mécanique du bois imprégné, de sorte à obtenir une pâte à papier mécanique. Le raffinage mécanique comprend un raffinage mécanique primaire (également appelé défibrage), destiné à mettre en pâte le bois éventuellement, suivi d'au moins un raffinage mécanique secondaire, destiné à développer les aptitudes papetières des fibres. Le raffinage secondaire est éventuellement suivi d'un ou plusieurs raffinages mécaniques ultérieurs (raffinage tertiaire, raffinage des refus, etc.).After the impregnation step (and the optional chemical post-treatment step), mechanical refining of the impregnated wood is carried out so as to obtain a mechanical pulp. Mechanical refining includes a primary mechanical refining (also known as pulping), intended to pulp the wood possibly, followed by at least a secondary mechanical refining, intended to develop the papermaking capabilities of the fibers. Secondary refining is eventually followed by one or more subsequent mechanical refining (tertiary refining, refining of refusals, etc.).
Le raffinage mécanique est préférentiellement effectué sous pression de façon à permettre une séparation plus sélective des fibres.The mechanical refining is preferably carried out under pressure so as to allow a more selective separation of the fibers.
Le raffinage primaire peut être mis en oeuvre par broyage ou râpage du bois à la meule (sous courant d'eau) ou dans un raffineur à disques.Primary refining can be carried out by grinding or grating the wood with the grinding wheel (under water flow) or in a disc refiner.
Selon un mode de réalisation, le raffinage primaire du bois est mis en oeuvre dans un raffineur à disques. La pression est de préférence ajustée de sorte à atteindre une température de raffinage comprise entre 105°C et 115°C. Avantageusement, la pression va de 0,5 à 5 bar, de préférence de 1 à 3 bar. La vitesse de rotation des disques va de préférence de 1000 à 5000 tours/minute, de préférence de 1000 à 3000 tours/minute.According to one embodiment, the primary refining of the wood is carried out in a disc refiner. The pressure is preferably adjusted so as to reach a refining temperature of between 105 ° C and 115 ° C. Advantageously, the pressure ranges from 0.5 to 5 bar, preferably from 1 to 3 bar. The rotational speed of the discs is preferably from 1000 to 5000 rpm, preferably from 1000 to 3000 rpm.
Selon un mode de réalisation, le raffinage secondaire du bois est mis en oeuvre dans un raffineur à disques. Le raffinage secondaire est de préférence mis en oeuvre sous une pression allant de 0,1 à 5 bar, de préférence de 0,5 à 3 bar. La vitesse de rotation des disques va de préférence de 1000 à 5000 tours/minute, de préférence de 1000 à 3000 tours/minute.According to one embodiment, the secondary refining of the wood is carried out in a disc refiner. The secondary refining is preferably carried out at a pressure of from 0.1 to 5 bar, preferably from 0.5 to 3 bar. The rotational speed of the discs is preferably from 1000 to 5000 rpm, preferably from 1000 to 3000 rpm.
Selon un mode de réalisation, le raffinage secondaire est mis en oeuvre de sorte à disposer à son issue de pâtes de taux d'égouttage allant de 250 à 50 mL CSF (Canadian Standard Freeness).According to one embodiment, the secondary refining is carried out so as to have at its disposal dough rate pasta ranging from 250 to 50 mL CSF ( Canadian Standard Freeness ).
La ou les étapes de raffinage ultérieures au défibrage peuvent comprendre plusieurs stades. Par exemple, après le défibrage, on peut séparer le produit en une fraction acceptée et une fraction rejetée, et raffiner la fraction rejetée avant de la mélanger avec la fraction acceptée. Il est possible de prévoir plusieurs fois de telles séparations intermédiaires.The refining step (s) subsequent to defibration can comprise several stages. For example, after defibering, the product can be separated into an accepted fraction and a rejected fraction, and the rejected fraction refined before mixing with the accepted fraction. It is possible to provide for such intermediate separations several times.
A l'issue du raffinage, on obtient une pâte à papier mécanique qui peut être notamment:
- une pâte à papier mécanique de défibreur (SGW) obtenue à partir de rondins ou de blocs raffinés à pression atmosphérique avec des défibreurs à meule ;
- une pâte à papier mécanique de défibreur sous pression (PGW) obtenue à partir de rondins ou de blocs raffinés sous pression avec des défibreurs à meule ;
- une pâte à papier mécanique de raffineur (RMP) obtenue à partir de copeaux ou de bûchettes dans des raffineurs travaillant à la pression atmosphérique ;
- une pâte à papier thermomécanique (TMP) ou thermomécanique haute température (HTMP) obtenue à partir de copeaux ou de bûchettes dans des raffineurs après traitement thermique du bois par étuvage à la vapeur d'eau à pression élevée ;
- une pâte à papier chimicothermomécanique (CTMP) obtenue par traitement chimique en présence d'une composition chimique comprenant un agent alcalin et un agent réducteur à une température supérieure ou égale à 100°C et raffinage sous pression.
- a mechanical shredding paper pulp (SGW) obtained from logs or refined blocks at atmospheric pressure with grinding wheels;
- pressurized mechanical pulp (PGW) pulp obtained from logs or refined pressurized blocks with grinding wheels;
- a mechanical pulp refiner (RMP) obtained from chips or sticks in refiners working at atmospheric pressure;
- a thermomechanical (TMP) or high temperature thermomechanical pulp (HTMP) obtained from chips or logs in refiners after heat treatment of the wood by steaming at high pressure;
- a chemothermothermomechanical pulp (CTMP) obtained by chemical treatment in the presence of a chemical composition comprising an alkaline agent and a reducing agent at a temperature greater than or equal to 100 ° C and refining under pressure.
A l'issue du raffinage, on obtient une pâte à papier mécanique présentant de préférence un degré de blancheur, mesuré conformément à la norme ISO 2470, supérieur ou égal à 50%, de préférence supérieur ou égal à 55%, idéalement supérieur ou égal à 57 %.At the end of the refining, a mechanical paper pulp is obtained, preferably having a degree of whiteness, measured according to ISO 2470, greater than or equal to 50%, preferably greater than or equal to 55%, ideally greater than or equal to at 57%.
L'économie en énergie spécifique réalisée grâce à l'invention est avantageusement supérieure ou égale à 10%, voire supérieur ou égal à 12%, voire supérieur ou égal à 14%, voire supérieur ou égal à 18% voire supérieur ou égal à 32%, comparativement à un procédé de fabrication d'une pâte à papier mécanique obtenue par raffinage d'un bois pré-imprégné dans les mêmes conditions mais avec de l'eau.The specific energy saving achieved by virtue of the invention is advantageously greater than or equal to 10%, even greater than or equal to 12%, even greater than or equal to 14%, even greater than or equal to 18%, or even greater than or equal to 32%. %, compared to a process for manufacturing a mechanical paper pulp obtained by refining a wood pre-impregnated under the same conditions but with water.
La chélation, lorsque mise en oeuvre, intervient de préférence après l'étape d'imprégnation (c'est-à-dire une fois que l'étape d'imprégnation est achevée), avantageusement après le raffinage, afin d'éviter une éventuelle interaction inhibitrice avec l'enzyme. La chélation comprend la mise en contact de la pâte à papier mécanique issue du raffinage avec une composition de chélation comprenant un agent chélatant, ladite composition de chélation étant de préférence une solution aqueuse.The chelation, when used, preferably occurs after the impregnation stage (that is to say once the impregnation stage is complete), advantageously after the refining, in order to avoid a possible inhibitory interaction with the enzyme. The chelation comprises contacting the mechanical pulp resulting from the refining with a chelating composition comprising a chelating agent, said chelating composition preferably being an aqueous solution.
L'agent chélatant peut être tout composé chimique conventionnellement utilisé à cette fin dans le domaine. De préférence il s'agit de l'acide éthylène diamine tétra-acétique ou de l'un de ses sels de sodium, ou de l'acide diéthylène triamine penta-acétique ou de l'un de ses sels de sodium.The chelating agent may be any chemical compound conventionally used for this purpose in the field. Preferably it is ethylene diamine tetraacetic acid or a sodium salt thereof, or diethylene triamine penta-acetic acid or a sodium salt thereof.
L'agent chélatant possède une affinité particulière pour les cations métalliques présents à l'état de traces dans la pâte à papier mécanique. L'objectif du traitement de chélation est de neutraliser ces cations en les séquestrant et de les retirer de la pâte à papier mécanique par lavage de celle-ci. La réalisation de l'étape de chélation contribue à améliorer la performance d'un traitement ultérieur de blanchiment (notamment au peroxyde d'hydrogène).The chelating agent has a particular affinity for trace metal cations in mechanical pulp. The purpose of the chelation treatment is to neutralize these cations by sequestering them and to remove them from the mechanical paper pulp by washing it. The completion of the chelation step contributes to improving the performance of a subsequent bleaching treatment (in particular with hydrogen peroxide).
La quantité d'agent chélatant utilisée lors de l'étape de chélation va de préférence de 0,05% à 3% en poids, de préférence de 0,1% à 2% en poids, de préférence de 0,2% à 1% en poids, en particulier de 0,3% à 0,5% en poids, relativement au poids de pâte à papier mécanique sèche.The amount of chelating agent used in the chelation step is preferably from 0.05% to 3% by weight, preferably from 0.1% to 2% by weight, preferably from 0.2% to 1% by weight. % by weight, in particular from 0.3% to 0.5% by weight, relative to the weight of dry mechanical pulp.
La durée de l'étape de chélation est de préférence supérieure ou égale à 30 minutes environ.The duration of the chelation step is preferably greater than or equal to about 30 minutes.
L'étape de chélation est effectuée à une température allant de préférence de 4°C à 95°C, de préférence de 25°C à 85°C, de préférence encore de 35°C à 80°C. Une température d'environ 60°C est particulièrement appropriée.The chelation step is carried out at a temperature of preferably 4 ° C to 95 ° C, preferably 25 ° C to 85 ° C, more preferably 35 ° C to 80 ° C. A temperature of about 60 ° C is particularly suitable.
La consistance de la pâte à papier mécanique lors de l'étape de chélation va de préférence de 0,5% à 20% en poids de pâte à papier mécanique sèche, de préférence de 2 à 15% en poids de pâte à papier mécanique sèche, de préférence encore de 3 à 12% en poids de pâte à papier mécanique sèche, relativement au poids de pâte à papier mécanique non sèche.The consistency of the mechanical paper stock in the chelation step is preferably 0.5% to 20% by weight of dry mechanical paper stock, preferably 2 to 15% by weight of dry mechanical stock more preferably from 3 to 12% by weight of dry mechanical pulp, relative to the weight of dry mechanical pulp.
Le blanchiment intervient de préférence après la chélation (ou après le raffinage si la chélation est absente), c'est-à-dire une fois que l'étape de chélation (ou l'étape de raffinage si la chélation est absente) est achevée.The bleaching preferably occurs after the chelation (or after refining if the chelation is absent), that is to say once the chelation step (or the refining step if the chelation is absent) is completed. .
Le blanchiment comprend la mise en contact de la pâte à papier mécanique issue de l'étape de chélation (ou de raffinage si la chélation est absente) avec une composition de blanchiment.Bleaching comprises contacting the mechanical paper pulp from the chelation step (or refining if the chelation is absent) with a bleaching composition.
La consistance lors de l'étape de blanchiment va de préférence de 1% à 50% en poids de pâte à papier mécanique sèche, de préférence de 10 à 40% en poids de pâte à papier mécanique sèche, de préférence encore de 20 à 30% en poids de pâte à papier mécanique sèche, relativement au poids de pâte à papier mécanique non sèche.The consistency during the bleaching step is preferably from 1% to 50% by weight of dry mechanical pulp, preferably from 10 to 40% by weight of dry mechanical pulp, more preferably from 20 to 30% by weight. % by weight of dry mechanical pulp, relative to the weight of dry mechanical pulp.
Le blanchiment présente une cinétique de réaction plus rapide à haute consistance (alors que pour la chélation, la cinétique de réaction est rapide même à basse consistance). On peut augmenter la consistance de la pâte à papier mécanique en la pressant par exemple, et en éliminant des filtrats comprenant notamment les métaux chélatés.Bleaching has faster reaction kinetics at high consistency (whereas for chelation reaction kinetics are fast even at low consistency). The consistency of the mechanical paper stock can be increased by pressing it, for example, and by eliminating filtrates comprising in particular the chelated metals.
La mise en contact s'effectue de préférence par simple mélange de la composition de blanchiment avec la pâte à papier. Le type d'appareillage utilisé pour le mélange est adapté en fonction de la consistance de la pâte à papier : mélange direct au moyen d'une pompe d'injection si la consistance est basse ou moyenne (moins de 10%) ; mélangeur ou mixer pour une consistance plus élevée (jusqu'à 40% environ).The contacting is preferably by simple mixing of the bleaching composition with the paper pulp. The type of equipment used for mixing is adapted according to the consistency of the pulp: direct mixing by means of an injection pump if the consistency is low or medium (less than 10%); mixer or mixer for a higher consistency (up to about 40%).
La composition de blanchiment est de préférence une solution aqueuse. La composition de blanchiment comprend de préférence un agent de blanchiment et un agent alcalin.The bleaching composition is preferably an aqueous solution. The bleaching composition preferably comprises a bleaching agent and an alkaline agent.
L'agent de blanchiment peut être tout composé chimique conventionnellement utilisé à cette fin dans le domaine. De préférence il s'agit de peroxyde d'hydrogène ou d'hydrosulfite de sodium.The bleaching agent may be any chemical compound conventionally used for this purpose in the field. Preferably it is hydrogen peroxide or sodium hydrosulfite.
La quantité d'agent de blanchiment utilisée va de préférence de 0,5% à 10% en poids, de préférence de 1% à 8% en poids, de préférence de 1,5% à 6% en poids, en particulier de 2% à 4% en poids, relativement au poids de pâte à papier mécanique sèche.The amount of bleaching agent used is preferably from 0.5% to 10% by weight, preferably from 1% to 8% by weight, preferably from 1.5% to 6% by weight. weight, in particular from 2% to 4% by weight, relative to the weight of dry mechanical pulp.
L'agent alcalin peut être choisi parmi les oxydes, hydroxydes, silicates et carbonates des métaux alcalins et métaux alcalino-terreux, l'ammoniac, l'ammoniaque et les mélanges de ceux-ci. Parmi les espèces basiques préférées pour le choix de l'agent alcalin, on peut citer l'hydroxyde de potassium, l'hydroxyde de sodium, l'hydroxyde de magnésium, l'hydroxyde de calcium, le carbonate de sodium, le silicate de sodium, le carbonate de magnésium et leurs mélanges. L'hydroxyde de sodium, l'hydroxyde de potassium ou leur mélange est particulièrement préféré. De préférence, l'agent alcalin de la composition de blanchiment comprend du silicate de sodium. Le silicate de sodium a une fonction auxiliaire de stabilisation de l'agent de blanchiment (notamment le peroxyde d'hydrogène). Il est également possible de prévoir dans la composition de blanchiment un autre agent stabilisant en plus ou à la place du silicate de sodium. Les composés de type polyhydroxyacrylate constituent des agents stabilisants possibles.The alkaline agent may be selected from oxides, hydroxides, silicates and carbonates of alkali metals and alkaline earth metals, ammonia, ammonia and mixtures thereof. Among the basic species preferred for the choice of the alkaline agent, mention may be made of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, sodium silicate magnesium carbonate and mixtures thereof. Sodium hydroxide, potassium hydroxide or their mixture is particularly preferred. Preferably, the alkaline agent of the bleaching composition comprises sodium silicate. Sodium silicate has an auxiliary stabilizing function of the bleaching agent (especially hydrogen peroxide). It is also possible to provide in the bleaching composition another stabilizing agent in addition to or instead of sodium silicate. Polyhydroxyacrylate compounds are possible stabilizing agents.
La quantité d'agent alcalin utilisée va de préférence de 0,5% à 10% en poids, de préférence de 1% à 6% en poids, de préférence de 1,4% à 4% en poids, en particulier de 1,6% à 2,5% en poids, relativement au poids de pâte à papier mécanique sèche.The amount of alkaline agent used is preferably from 0.5% to 10% by weight, preferably from 1% to 6% by weight, preferably from 1.4% to 4% by weight, in particular from 1% to 6% to 2.5% by weight, relative to the weight of dry mechanical pulp.
La composition de blanchiment peut également comprendre un agent chélatant tel que défini ci-dessus, notamment si l'étape de chélation est absente ou a abouti à une chélation incomplète.The bleaching composition may also comprise a chelating agent as defined above, especially if the chelation step is absent or has resulted in incomplete chelation.
Il faut noter que la composition de blanchiment peut être préparée séparément puis mise en contact avec la pâte à papier mécanique, mais elle peut également être préparée directement au contact de la pâte à papier mécanique. Dans ce deuxième cas, les différents composés de la composition de blanchiment sont successivement directement ajoutés à la pâte à papier mécanique.It should be noted that the bleaching composition can be prepared separately and then brought into contact with the mechanical paper pulp, but it can also be prepared directly in contact with the mechanical pulp. In this second case, the various compounds of the bleaching composition are successively directly added to the mechanical pulp.
La durée de l'étape de blanchiment varie selon le type d'agent utilisé.The duration of the bleaching step varies depending on the type of agent used.
Dans le cas du peroxyde d'hydrogène, cette durée va de préférence de 10 minutes à 8 heures, de préférence de 30 minutes à 6 heures, de préférence encore de 2 heures à 4 heures.In the case of hydrogen peroxide, this duration is preferably from 10 minutes to 8 hours, preferably from 30 minutes to 6 hours, more preferably from 2 hours to 4 hours.
L'étape de blanchiment est effectuée à une température allant de préférence de 4°C à 95°C, de préférence de 25°C à 85°C, de préférence encore de 35°C à 80°C. Une température d'environ 70°C est particulièrement appropriée.The bleaching step is carried out at a temperature of preferably 4 ° C to 95 ° C, preferably 25 ° C to 85 ° C, more preferably 35 ° C to 80 ° C. A temperature of about 70 ° C is particularly suitable.
L'étape de blanchiment peut être répétée plusieurs fois, par exemple deux fois.The bleaching step can be repeated several times, for example twice.
A l'issue du premier blanchiment, on obtient une pâte à papier mécanique présentant de préférence un degré de blancheur, mesuré conformément à la norme ISO 2470-2:2008, supérieur ou égal à 57%, de préférence encore supérieur ou égal à 60%, idéalement supérieur ou égal à 62% voire supérieur ou égal à 65%.At the end of the first bleaching, a mechanical pulp having a degree of whiteness, measured in accordance with ISO 2470-2: 2008, is obtained, greater than or equal to 57%, more preferably greater than or equal to 60 %, ideally greater than or equal to 62% or even greater than or equal to 65%.
L'invention se rapporte enfin à un procédé de fabrication de papier comprenant la fabrication de pâte à papier mécanique selon le procédé précédent puis l'utilisation de cette pâte à papier mécanique pour produire du papier.Finally, the invention relates to a papermaking process comprising the manufacture of mechanical pulp according to the preceding method and then the use of this mechanical paper pulp to produce paper.
La pâte à papier mécanique peut notamment être séchée et façonnée en feuilles dans une machine à papier conventionnelle dans le domaine.The mechanical paper stock can be dried and shaped into sheets in a conventional paper machine in the field.
La pâte à papier mécanique peut également être introduite dans une machine presse-pâte pour être séchée et préformée sous forme de feuilles. Les feuilles peuvent être mises en balles afin d'être transférées à une usine de fabrication de papier pour y subir éventuellement des traitements ultérieurs.The mechanical paper stock may also be fed to a dough press machine to be dried and preformed into sheets. The leaves can be baled for transfer to a paper mill for possible subsequent processing.
Avantageusement, la résistance à la déchirure du papier obtenu grâce à la mise en oeuvre de la présente invention (mesurée selon la norme NF EN 21974 après mise en feuilles de la pâte à papier mécanique conformément à la norme NF EN 5269-1) est augmentée de 3%, voire de 9%, voire de 11%, relativement à une pâte à papier mécanique obtenue par raffinage d'un bois pré-imprégné avec de l'eau.Advantageously, the tear strength of the paper obtained by virtue of the implementation of the present invention (measured according to the standard NF EN 21974 after placing sheets of the mechanical pulp in accordance with the standard NF EN 5269-1) is increased 3%, or even 9%, or even 11%, in relation to a mechanical pulp obtained by refining a wood pre-impregnated with water.
L'activité de l'enzyme laccase est exprimée en LAMU/mL. Une unité LAMU correspond à la quantité d'enzyme laccase qui, sous des conditions données (pH 7,5 et température 30°C), dégrade 1 µmol de syringaldazine par minute. Cette activité est déterminable à partir de mesures d'absorbance par spectrophotométrie. En effet, au cours de la réaction selon laquelle une laccase (E.C. 1.10.3.2), p-diphénol: dioxygène oxidoréductase, catalyse l'oxydation de syringaldazine (4,4'-[azinobis(méthanylylidine)]bis(2,6-diméthoxyphénol)) en quinone correspondante (4,4'-[azobis(méthanylylidine)]bis(2,6-diméthoxycyclohexa-2,5-dièn-1-one), il se produit un changement d'absorption par la syringaldazine à une longueur d'onde de 530 nm.
Pour la mesure, on utilise :
- une solution tampon (pH 7,5) à 25mM de Tris/malate (préparée à partir de 25 mL d'une solution aqueuse à 1,0 M de Tris(hydroxyméthyl)aminométhane, 5mL d'une solution aqueuse à 1,0 M d'acide maléique, et la quantité suffisante d'eau pour obtenir 1L de solution tampon),
- une solution de syringaldazine à 0,28mM (préparée en diluant 25 mL de solution alcoolique de syringaldazine à 0,56mM dans la quantité suffisante d'eau pour obtenir 50 mL de solution de syringalazine, la solution alcoolique de syringaldazine à 0,56mM étant elle-même obtenue par dissolution de 10,0 mg de syringaldazine (Sigma S-7896) dans la quantité suffisante d'éthanol à 96% pour obtenir 50mL de solution alcoolique de syringaldazine),
- une solution aqueuse d'éthanol à 6% en poids,
- une solution de dilution pour l'enzyme (contenant 25,0g de PEG 6000, 5,0g de Triton X-100 et une quantité suffisante d'eau pour obtenir 0,5L de solution). Les échantillons de laccase à tester sont dilués d'un facteur F à l'aide de cette solution pour approcher une activité de 0,18 LAMU/mL.
L'activité est calculée selon la formule :
For the measurement, we use:
- a buffer solution (pH 7.5) at 25mM Tris / malate (prepared from 25 mL of a 1.0 M aqueous solution of Tris (hydroxymethyl) aminomethane, 5 mL of a 1.0 M aqueous solution of maleic acid, and the sufficient amount of water to obtain 1L of buffer solution),
- 0.28mM syringaldazine solution (prepared by diluting 25mL of 0.56mM syringaldazine alcoholic solution in the sufficient amount of water to obtain 50mL of syringalazine solution, the 0.56mM syringaldazine alcohol solution being -Even obtained by dissolving 10.0 mg of syringaldazine (Sigma S-7896) in the sufficient amount of 96% ethanol to obtain 50 mL of alcoholic syringaldazine solution),
- an aqueous solution of ethanol at 6% by weight,
- a dilution solution for the enzyme (containing 25.0g of PEG 6000, 5.0g of Triton X-100 and a sufficient amount of water to obtain 0.5L of solution). The laccase samples to be tested are diluted F factor with this solution to approach an activity of 0.18 LAMU / mL.
The activity is calculated according to the formula:
L'indice d'égouttage, de nom anglophone "Canadian Standard Freeness" (CSF) est mesuré conformément à la norme internationale ISO 5267-2. Il traduit la facilité avec laquelle l'eau peut être extraite d'une pâte à papier mécanique. Plus l'indice est petit, plus la pâte à papier mécanique s'égoutte mal. Ce paramètre est un indicateur du degré de raffinage atteint lors d'un raffinage mécanique de la pâte.The "Canadian Standard Freeness" (CSF) dewatering index is measured according to the international standard ISO 5267-2. It reflects the ease with which water can be extracted from a mechanical pulp. The smaller the index, the more mechanical pulp drains poorly. This parameter is an indicator of the degree of refining achieved during mechanical refining of the pulp.
La blancheur de la pâte à papier mécanique est déterminée par mesure de son facteur de réflectance diffuse dans le bleu tel que défini dans la norme ISO 2470-2 : 2008.The whiteness of the mechanical paper stock is determined by measuring its diffuse blue reflectance factor as defined in ISO 2470-2: 2008.
Pour un essai X, le gain de blancheur correspond à la différence entre la blancheur mesurée à l'issue d'un blanchiment QP et la blancheur mesurée à l'issue du raffinage.For an X test, the whiteness gain corresponds to the difference between whiteness measured at the end of QP whitening and the whiteness measured at the end of refining.
L'énergie spécifique totale de raffinage est obtenue en sommant les valeurs des consommations électriques mesurées pour chacune des étapes préalables au raffinage et jusqu'à son issue (par exemple compression de copeaux de bois, défibrage et raffinage secondaire).The total specific energy of refining is obtained by summing up the values of the electrical consumptions measured for each of the stages preceding the refining and until its exit (for example compression of wood chips, defibration and secondary refining).
Pour un essai X, l'économie d'énergie réalisée correspond à la différence entre l'énergie spécifique de raffinage d'un essai de référence, réalisé dans les mêmes conditions que l'essai X à la différence près qu'il met en oeuvre une composition d'imprégnation abiotique, et l'énergie spécifique de raffinage de l'essai X.For an X test, the realized energy saving corresponds to the difference between the specific refining energy of a reference test, carried out in the same conditions that the test X with the difference that it implements an abiotic impregnation composition, and the specific energy of refining of the test X.
Afin d'évaluer la résistance des fibres dans la pâte à papier mécanique fabriquée, cette dernière est mise en feuilles conformément à la norme NF EN 5269-1 et la résistance à la déchirure des feuilles est mesurée selon la norme NF EN 21974.In order to evaluate the resistance of the fibers in the manufactured mechanical paper pulp, the latter is put into sheets according to the NF EN 5269-1 standard and the tear strength of the sheets is measured according to standard NF EN 21974.
Les exemples suivants illustrent l'invention sans la limiter.The following examples illustrate the invention without limiting it.
Les matières premières utilisées sont les suivantes :
- copeaux frais d'épicéa de Norvège fournis par la société HOLMEN,
- copeaux issus de rondins frais de peuplier fournis par une exploitation forestière de la région lyonnaise,
- copeaux frais d'eucalyptus d'Espagne fournis par la société ENCE,
- laccases de Myceliophthora commercialisée par la société NOVOZYMES sous la référence NS51003, présentant une activité de 1000 LAMU/mL mesurée conformément au protocole indiqué précedemment,
- diéthylhydroxylamine (DEHA) commercialisée par la société ARKEMA,
- 4-Hydroxy-3,5-diméthoxybenzaldehyde (Syringaldéhyde),
- acide diéthylène triamine penta acétique (DTPA),
- peroxyde d'hydrogène,
- silicate de sodium,
- hydroxyde de sodium,
- sulfate de magnésium.
- Norway spruce shavings supplied by HOLMEN,
- chips from fresh poplar logs supplied by a logging company in the Lyon region,
- fresh eucalyptus chips from Spain supplied by ENCE,
- laccases of Myceliophthora sold by the company NOVOZYMES under the reference NS51003, having an activity of 1000 LAMU / mL measured according to the protocol indicated previously,
- diethylhydroxylamine (DEHA) marketed by the company Arkema,
- 4-Hydroxy-3,5-dimethoxybenzaldehyde (Syringaldehyde),
- diethylene triamine penta acetic acid (DTPA),
- hydrogen peroxide,
- sodium silicate,
- sodium hydroxide,
- magnesium sulfate.
Des copeaux de bois d'épicéa sont soumis à un étuvage à la vapeur d'eau à pression atmosphérique pendant 15 minutes, puis introduits dans une vis de compression (modèle Modular Screw Device Impressafiner™ 6 pouces de ANDRITZ AG), raccordée à un cuvier renfermant la composition d'imprégnation. En sortie de vis, les copeaux compressés sont directement expulsés dans la composition d'imprégnation, où ils sont laissés à incuber pendant 1 heure. La composition d'imprégnation est extraite, puis les copeaux sont soumis à un étuvage à la vapeur d'eau pendant 5 minutes pour stopper l'activité enzymatique.Spruce chips are steamed at atmospheric pressure for 15 minutes and then introduced into a compression screw (ANDRITZ AG Modular Screw Device Impressafiner ™ 6 inch), connected to a vat containing the impregnating composition. At the outlet of the screw, the compressed chips are directly expelled into the impregnating composition, where they are allowed to incubate for 1 hour. The impregnating composition is extracted and then the chips are subjected to steam steaming for 5 minutes to stop the enzymatic activity.
Les copeaux ainsi pré-traités sont transférés dans un pilote de mise en pâte à papier mécanique (raffineur à disques) pour y être mécaniquement défibrés puis raffinés. Le défibrage (raffinage primaire) est mis en oeuvre à une pression de 2 bar et rotation de disques à 3000 tours/min. Le raffinage secondaire est mis en oeuvre à une pression de 1 bar. L'écart entre les disques est ajusté progressivement de sorte à obtenir cinq pâtes à papier mécanique d'indices d'égouttage allant de 250 mL à 50 mL CSF. On mesure la blancheur des cinq pâtes à papier mécanique selon la norme ISO 2470-2 :2008.The chips thus pre-treated are transferred into a mechanical pulping pilot (disc refiner) to be mechanically defibrated and then refined. The defibration (primary refining) is carried out at a pressure of 2 bar and disc rotation at 3000 revolutions / min. The secondary refining is carried out at a pressure of 1 bar. The gap between the discs is gradually adjusted so as to obtain five mechanical paper pulps of freeness ranging from 250 mL to 50 mL CSF. The whiteness of the five mechanical paper stocks is measured according to ISO 2470-2: 2008.
Après raffinage, chaque pâte à papier mécanique TMP obtenue est blanchie selon un procédé en deux étapes comprenant une étape de chélation (Q) puis un blanchiment au peroxyde d'hydrogène (P). Lors de l'étape Q, la consistance de la pâte à papier mécanique est ajustée à 10% en poids. L'étape Q comprend la mise en contact, à une température de 60°C pendant 30 minutes, de cette pâte à papier mécanique avec 0,4% en poids d'acide diéthylène triamine penta acétique (DTPA) relativement au poids total de pâte à papier mécanique sèche. Lors de l'étape P, la consistance de la pâte à papier mécanique obtenue à l'issue de l'étape Q est ajustée à 25% en poids. L'étape P comprend la mise en contact, à une température de 70°C pendant 120 minutes, de cette pâte à papier mécanique avec une composition de blanchiment comprenant 3% de peroxyde d'hydrogène, 1,9% d'hydroxyde de sodium et 2% de silicate de sodium en pourcentages en poids relativement au poids total de pâte à papier mécanique sèche. On mesure la blancheur des cinq pâtes à papier mécanique selon la norme ISO 2470-2 :2008.After refining, each obtained TMP mechanical pulp is bleached in a two-step process comprising a chelation step (Q) followed by hydrogen peroxide bleaching (P). In step Q, the consistency of the mechanical paper stock is adjusted to 10% by weight. Step Q includes putting in contact at a temperature of 60 ° C for 30 minutes, this mechanical paper pulp with 0.4% by weight of diethylene triamine penta acetic acid (DTPA) relative to the total weight of dry mechanical pulp. In step P, the consistency of the mechanical pulp obtained at the end of step Q is adjusted to 25% by weight. Step P comprises contacting, at a temperature of 70 ° C for 120 minutes, this mechanical paper stock with a bleaching composition comprising 3% hydrogen peroxide, 1.9% sodium hydroxide and 2% sodium silicate in percentages by weight relative to the total weight of dry mechanical pulp. The whiteness of the five mechanical paper stocks is measured according to ISO 2470-2: 2008.
Les pâtes à papier mécanique sont ensuite mises en feuilles conformément à la norme NF EN 5269-1. On mesure la résistance à la déchirure des feuilles selon la norme NF EN 21974.The mechanical paper stocks are then put into sheets in accordance with standard NF EN 5269-1. The tear resistance of the sheets is measured according to standard NF EN 21974.
On calcule la consommation d'énergie spécifique comme décrit plus haut, à savoir en sommant la consommation énergétique de chaque étape du procédé de fabrication de pâte à papier mécanique jusqu'à l'issue du raffinage : 1er étuvage, compression/expulsion, 2nd étuvage, défibrage et raffinages ultérieurs.The specific energy consumption is calculated as described above, namely by summing up the energy consumption of each step of the mechanical pulping process until the end of the refining: 1 st steaming, compression / expulsion, 2 nd parboiling, defibration and subsequent refining.
Les résultats sont reportés dans le tableau 2 ci-dessous après interpolation des valeurs à 100 mL CSF.
Concernant la consommation en énergie spécifique de raffinage, l'essai 3 selon l'invention montre que :
- l'invention permet une réduction significative de la consommation en énergie spécifique de raffinage;
- la combinaison de laccase et de DEHA permet une réduction de la consommation en énergie spécifique de raffinage plus importante que les composés pris séparément (essais 4 et 5);
- en combinaison avec la laccase, la DEHA permet une réduction de la consommation en énergie spécifique de raffinage plus importante que le syringaldéhyde (essai 2).
- the invention allows a significant reduction in the specific energy consumption of refining;
- the combination of laccase and DEHA allows a greater reduction in the refining specific energy consumption than the compounds taken separately (tests 4 and 5);
- in combination with laccase, DEHA allows a greater reduction in the specific energy consumption of refining than syringaldehyde (test 2).
Concernant la blancheur de la pâte à papier mécanique, l'essai 3 selon l'invention montre que :
- l'invention permet d'augmenter significativement le degré de blancheur de la pâte à papier mécanique fabriquée (essai 1) ;
- la combinaison de laccase et DEHA permet d'augmenter le degré de blancheur de la pâte à papier contrairement aux composés pris séparément (essais 4 et 5 versus essai 1);
- en combinaison avec la laccase, la DEHA augmente davantage le degré de blancheur de la pâte à papier que la syringaldéhyde (essai 2).
- the invention makes it possible to significantly increase the degree of whiteness of the manufactured mechanical pulp (test 1);
- the combination of laccase and DEHA makes it possible to increase the degree of whiteness of the paper pulp, unlike the compounds taken separately (tests 4 and 5 versus test 1);
- in combination with laccase, DEHA further increases the degree of whiteness of the pulp than syringaldehyde (test 2).
Concernant la résistance à la déchirure du papier, l'essai 3 montre que l'invention préserve les qualités papetières des fibres.With regard to the tear strength of the paper, the test 3 shows that the invention preserves the paper qualities of the fibers.
Ces essais complémentaires sont réalisés afin de déterminer l'influence de la quantité en réactifs utilisés dans la composition d'imprégnation selon l'invention. La composition d'imprégnation utilisée pour chaque essai est donnée dans le tableau 1. La composition d'imprégnation de l'essai 6 correspond à une composition abiotique de référence. Les compositions des essais 7 et 8 sont conformes à l'invention. On procède de manière identique aux essais 1 à 4. Les résultats sont reportés dans le tableau 3 ci-dessous.
L'essai 7 (comparativement à l'essai 6) montre que, même lorsque les quantités en laccase et en DEHA sont diminuées, la composition d'imprégnation selon l'invention permet de réduire la consommation énergétique spécifique de raffinage, d'augmenter le degré de blancheur de la pâte à papier mécanique fabriquée et de préserver la résistance du papier qui en est issu.Test 7 (compared with test 6) shows that, even when the amounts of laccase and DEHA are decreased, the impregnating composition according to the invention makes it possible to reduce the specific energy consumption of refining, to increase the degree of whiteness of the manufactured mechanical pulp and to preserve the strength of the paper which is derived therefrom.
L'essai 8 (comparativement aux essais 6 et 7) montre qu'en dessous d'une certaine teneur en médiateur, la composition d'imprégnation ne permet plus de réduire la consommation énergétique spécifique de raffinage mais permet tout de même d'augmenter le degré de blancheur de la pâte à papier mécanique fabriquée et de préserver la résistance du papier qui en est issu.Test 8 (compared to tests 6 and 7) shows that below a certain mediator content, the impregnating composition no longer makes it possible to reduce the specific energy consumption of the refining operation but nevertheless makes it possible to increase the degree of whiteness of the manufactured mechanical pulp and to preserve the strength of the paper which is derived therefrom.
On procède à la mise en pâte de copeaux de bois de peuplier selon des étapes d'étuvage, de compression et d'imprégnation identiques à celles des essais 1 à 4. La composition d'imprégnation utilisée pour chacun des essais est indiquée dans le tableau 1. En particulier, la composition d'imprégnation de l'essai 9 correspond à une composition abiotique qui sert de référence. Les compositions des essais 10 et 11 sont conformes à l'invention.Poplar wood chips are pulped according to the steaming, pressing and impregnation stages identical to those of tests 1 to 4. The impregnation composition used for each of the tests is indicated in the table. In particular, the impregnating composition of test 9 corresponds to an abiotic composition which serves as a reference. The compositions of tests 10 and 11 are in accordance with the invention.
Un second traitement des copeaux est mis en oeuvre par ajout dans le cuvier de 2% en poids de sulfite de sodium et 1% en poids d'hydroxyde de sodium, par rapport au poids total de copeaux secs. La température du milieu est portée à 125°C et les copeaux sont laissés à imprégner pendant 15 minutes.A second treatment of chips is carried out by adding to the vat 2% by weight of sodium sulfite and 1% by weight of sodium hydroxide, relative to the total weight of dry chips. The temperature of the medium is brought to 125 ° C. and the chips are left to impregnate for 15 minutes.
Les copeaux imprégnés sont soumis à un défibrage à une pression de 2 bar et rotation de disques à 3000 tours par minute, puis à un second raffinage mécanique à pression atmosphérique. L'écart entre les disques est ajusté progressivement de sorte à obtenir cinq pâtes à papier mécanique d'indices d'égouttage allant de 400 à 100 mL CSF. La blancheur des cinq pâtes à papier mécanique est déterminée selon la norme ISO 2470-2 :2008.The impregnated chips are subjected to defibration at a pressure of 2 bar and rotation of disks at 3000 revolutions per minute, then to a second mechanical refining at atmospheric pressure. The gap between the discs is gradually adjusted so as to obtain five mechanical paper pulps of freeness ranging from 400 to 100 mL CSF. The whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
Après le raffinage, chaque pâte à papier mécanique CTMP obtenue est soumise à un blanchiment comprenant trois étapes : une étape de chélation (Q), suivie de 2 traitements successifs au peroxyde d'hydrogène (PP).After the refining, each CTMP mechanical pulp obtained is bleached comprising three steps: a chelation step (Q) followed by two successive treatments with hydrogen peroxide (PP).
Lors de l'étape Q, la consistance de la pâte à papier mécanique est ajustée à 10% en poids. L'étape Q comprend la mise en contact, à une température de 60°C pendant 30 minutes, de cette pâte à papier mécanique avec 0,4% en poids d'acide diéthylène triamine penta acétique (DTPA) relativement au poids total de pâte à papier mécanique sèche.In step Q, the consistency of the mechanical paper stock is adjusted to 10% by weight. Step Q comprises contacting, at a temperature of 60 ° C for 30 minutes, this mechanical paper pulp with 0.4% by weight of diethylene triamine pentaacetic acid (DTPA) relative to the total weight of dough dry mechanical paper.
Lors de la première étape P (P1), la consistance de la pâte à papier mécanique obtenue à l'issue de l'étape Q est ajustée à 14% en poids. L'étape P1 comprend la mise en contact, à une température de 70°C pendant 120 minutes, de cette pâte à papier mécanique avec une composition de blanchiment comprenant 2,2% de peroxyde d'hydrogène, 1,5% d'hydroxyde de sodium, 1% de silicate de sodium, 0,075% de sulfate de magnésium, en pourcentages en poids relativement au poids total de pâte à papier mécanique sèche. La blancheur des cinq pâtes à papier mécanique est déterminée selon la norme ISO 2470-2 :2008.In the first step P (P1), the consistency of the mechanical pulp obtained at the end of step Q is adjusted to 14% by weight. Step P1 comprises contacting, at a temperature of 70 ° C for 120 minutes, this mechanical paper stock with a bleaching composition comprising 2.2% hydrogen peroxide, 1.5% hydroxide of sodium, 1% of sodium silicate, 0.075% of magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp. The whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
Lors de la seconde étape P (P2), la consistance de la pâte à papier mécanique obtenue à l'issue de l'étape P1 est ajustée à 20% en poids. L'étape P2 comprend la mise en contact, à une température de 70°C pendant 120 minutes, de cette pâte à papier mécanique avec une composition de blanchiment comprenant 3.4% de peroxyde d'hydrogène, 1,7% d'hydroxyde de sodium, 1.6% de silicate de sodium, 0.075% de sulfate de magnésium, en pourcentages en poids relativement au poids total de pâte à papier mécanique sèche. La blancheur des cinq pâtes à papier mécanique est déterminée selon la norme ISO 2470-2 :2008.In the second step P (P2), the consistency of the mechanical pulp obtained at the end of step P1 is adjusted to 20% by weight. Step P2 comprises contacting, at a temperature of 70 ° C. for 120 minutes, this mechanical paper pulp with a bleaching composition comprising 3.4% hydrogen peroxide, 1.7% sodium hydroxide. , 1.6% sodium silicate, 0.075% magnesium sulphate, in percentages by weight relative to the total weight of dry mechanical pulp. The whiteness of the five mechanical paper stocks is determined according to ISO 2470-2: 2008.
La consommation d'énergie spécifique du procédé est calculée pour chaque pâte à papier mécanique comme décrit plus haut.The specific energy consumption of the process is calculated for each mechanical pulp as described above.
Les résultats sont reportés dans le tableau 4 ci-dessous après interpolation des valeurs à 300 mL CSF.
Concernant la consommation en énergie spécifique :
- les essais 10 et 11 (comparativement à l'essai 9), tout particulièrement l'essai 10, montrent que l'utilisation d'une composition d'imprégnation selon l'invention lors du raffinage permet une réduction significative de la consommation énergétique spécifique de raffinage du procédé CTMP ;
- the tests 10 and 11 (compared with the test 9), especially the test 10, show that the use of an impregnating composition according to the invention during the refining allows a significant reduction in the specific energy consumption of refining the CTMP process;
Concernant la blancheur de la pâte à papier mécanique:
- les essais 10 et 11 (comparativement à l'essai 9) montrent que l'utilisation d'une composition d'imprégnation selon l'invention lors du raffinage permet l'obtention d'une pâte à papier mécanique CTMP plus blanche tant à l'issue du raffinage qu'à l'issue d'un blanchiment ultérieur de celle-ci ;
- l'invention augmente le degré de blancheur de la pâte à papier mécanique obtenue à l'issue du premier blanchiment mis en oeuvre après raffinage.
- the tests 10 and 11 (compared with the test 9) show that the use of an impregnating composition according to the invention during the refining makes it possible to obtain a whiter CTMP mechanical paper pulp at the same time. from refining only after a subsequent bleaching thereof;
- the invention increases the degree of whiteness of the mechanical pulp obtained after the first bleaching carried out after refining.
Claims (11)
- Method for producing mechanical paper pulp, comprising at least:- a step of impregnating an untreated wood, comprising contacting the untreated wood with an impregnating composition comprising, relative to its total weight, from 0.01% to 10% by weight of a laccase solution containing 1000 LAMU/mL of said solution, and from 0.1% to 10% by weight of a mediator of formula (I):
said impregnation composition being used at a rate of from 0.1 to 12 L/kg of the untreated wood for impregnation; and- a step of mechanically refining the impregnated wood, so as to obtain a mechanical paper pulp. - Method according to the preceding claim, wherein the mediator is diethyl hydroxylamine (DEHA).
- Method according to either one of the preceding claims, wherein the impregnating composition is used at a rate of from 1 to 10 L/kg of the untreated wood for impregnation.
- Method according to any one of the preceding claims, wherein the untreated wood is selected from coniferous woods, deciduous woods or mixtures thereof, preferably from a spruce wood, a poplar wood, a eucalyptus wood, or a mixture thereof.
- Method according to any one of the preceding claims, wherein the untreated wood is in the form of chips.
- Method for producing a mechanical paper pulp, comprising, in this order, the following steps:- optionally an operation of steaming an untreated wood,- optionally an operation of pressing an untreated wood,- at least one step of impregnating an untreated wood with an impregnating composition as defined in any one of Claims 1 to 3, to give an impregnated wood,- optionally an operation of steaming the impregnated wood,- at least one step of mechanically refining the impregnated wood, to give a mechanical pulp,- optionally a step of chelating the mechanical pulp,- optionally an operation of bleaching the mechanical pulp.
- Composition for impregnating an untreated wood, as defined in any one of Claims 1 to 3.
- Use of an impregnating composition as defined in any one of Claims 1 to 3 in a method for producing mechanical paper pulp, for lowering the energy consumption of said method.
- Use of an impregnating composition as defined in any one of Claims 1 to 3 in a method for producing mechanical paper pulp, for enhancing the whiteness of said pulp.
- Use of an impregnating composition as defined in any one of Claims 1 to 3 in a method for producing mechanical paper pulp comprising a step of mechanical refining, said impregnating composition being used before the step of mechanical refining.
- Papermaking process, comprising producing a mechanical paper pulp according to any one of Claims 1 to 6, and using this mechanical pulp for manufacturing paper.
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FR1158871A FR2980805B1 (en) | 2011-09-30 | 2011-09-30 | ENZYMATIC PRETREATMENT OF WOOD IN A PROCESS FOR THE MANUFACTURE OF MECHANICAL PAPER PULP |
PCT/FR2012/051998 WO2013045782A1 (en) | 2011-09-30 | 2012-09-06 | Enzymatic pretreatment of wood in a method for producing mechanical paper pulp |
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EP2761081B1 true EP2761081B1 (en) | 2018-08-08 |
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US (1) | US9834886B2 (en) |
EP (1) | EP2761081B1 (en) |
CN (2) | CN103842581A (en) |
CA (1) | CA2844380C (en) |
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WO (1) | WO2013045782A1 (en) |
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CN102392380A (en) * | 2005-05-04 | 2012-03-28 | 诺维信北美公司 | Chlorine dioxide treatment combination and method thereof |
WO2014146712A1 (en) * | 2013-03-20 | 2014-09-25 | Metgen Oy | Method for saving energy in paper production |
CN103243596B (en) * | 2013-05-17 | 2016-02-10 | 济南圣泉集团股份有限公司 | A kind of Acetate-grade pulp and preparation method thereof |
MX2016006238A (en) | 2013-11-18 | 2016-10-05 | Enzymatic Deinking Tech Llc | Enzymatic treatment of virgin fiber and recycled paper to reduce residual mineral oil levels for paper production. |
CN105256624A (en) * | 2015-09-18 | 2016-01-20 | 新疆国力源投资有限公司 | Method for preparing natural color bamboo pulp |
WO2017108431A1 (en) * | 2015-12-22 | 2017-06-29 | Metgen Oy | Method for producing mechanical pulp from a biomass comprising lignocellulosic material |
CN108560301B (en) * | 2018-04-23 | 2020-09-15 | 上海锴晨实业有限公司 | Solid slow-release type bio-enzyme pulping supplementary bleaching agent and preparation method thereof |
CN109098025B (en) * | 2018-08-06 | 2021-03-30 | 广西大学 | Method for preparing natural-color mechanical pulp by treating bagasse with laccase |
SE1950165A1 (en) * | 2019-02-12 | 2020-08-13 | Stora Enso Oyj | Method of producing a molded fiber product and molded fiber product |
CN110257453B (en) * | 2019-05-28 | 2023-03-28 | 中国林业科学研究院林产化学工业研究所 | Pretreatment method for preparing fermentable sugar by improving biological enzymolysis conversion rate of fiber raw material |
CN112726250A (en) * | 2021-01-11 | 2021-04-30 | 山东晨鸣纸业集团股份有限公司 | Low-solid-content sulfate-method continuous cooking process |
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FI895501A (en) * | 1989-11-17 | 1991-05-18 | Enso Gutzeit Oy | FOERFARANDE FOER TILLVERKNING AV MASSA. |
FI900544A (en) * | 1990-02-02 | 1991-08-03 | Enso Gutzeit Oy Tutkimuskeskus | FOERFARANDE FOER TILLVERKNING AV MASSA. |
US6267841B1 (en) | 1992-09-14 | 2001-07-31 | Steven W. Burton | Low energy thermomechanical pulping process using an enzyme treatment between refining zones |
ATE191927T1 (en) * | 1993-06-16 | 2000-05-15 | Call Hans Peter | MULTI-COMPONENT BLEACHING SYSTEM |
EP0717143A1 (en) * | 1994-12-16 | 1996-06-19 | Lignozym GmbH | Multicomponents system for modifying decomposing or bleaching of lignin or materials containing it or similar components and the way to use it |
DE19632623A1 (en) * | 1996-08-13 | 1998-02-19 | Consortium Elektrochem Ind | Multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances as well as methods for their use |
US6492005B1 (en) * | 1999-03-09 | 2002-12-10 | Konica Corporation | Ink jet recording sheet |
RU2407768C2 (en) | 2005-06-03 | 2010-12-27 | Андриц Аг | Method to reduce power consumption in production of thermomechanical wood pulp by means of low-temperature grinding of wood pulp of low and medium concentration |
CN100365198C (en) * | 2005-11-18 | 2008-01-30 | 山东轻工业学院 | Process for enzyme treating before pulping by plant fibre raw material |
MX2009005733A (en) | 2006-12-18 | 2009-06-08 | Danisco Us Inc Genencor Div | Novel laccases, compositions and methods of use. |
FI119062B (en) | 2006-12-28 | 2008-07-15 | Upm Kymmene Corp | Process for the manufacture of mechanical pulp |
CN100590255C (en) * | 2008-01-23 | 2010-02-17 | 山东轻工业学院 | Technique for chemomechanical pulp-making of poplar wood |
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US20140231034A1 (en) | 2014-08-21 |
CA2844380A1 (en) | 2013-04-04 |
WO2013045782A1 (en) | 2013-04-04 |
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CA2844380C (en) | 2016-11-08 |
CN108660826A (en) | 2018-10-16 |
CN103842581A (en) | 2014-06-04 |
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