CN116289330A - Degradable coating for food packaging paper and preparation process thereof - Google Patents
Degradable coating for food packaging paper and preparation process thereof Download PDFInfo
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- CN116289330A CN116289330A CN202310463102.6A CN202310463102A CN116289330A CN 116289330 A CN116289330 A CN 116289330A CN 202310463102 A CN202310463102 A CN 202310463102A CN 116289330 A CN116289330 A CN 116289330A
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- 238000000576 coating method Methods 0.000 title claims abstract description 212
- 239000011248 coating agent Substances 0.000 title claims abstract description 209
- 235000013305 food Nutrition 0.000 title claims abstract description 49
- 238000004806 packaging method and process Methods 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 94
- 229920001661 Chitosan Polymers 0.000 claims abstract description 75
- 235000013871 bee wax Nutrition 0.000 claims abstract description 72
- 239000012166 beeswax Substances 0.000 claims abstract description 72
- 108090000623 proteins and genes Proteins 0.000 claims abstract description 71
- 102000004169 proteins and genes Human genes 0.000 claims abstract description 71
- 150000003242 quaternary ammonium salts Chemical class 0.000 claims abstract description 69
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 60
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 53
- 239000000839 emulsion Substances 0.000 claims abstract description 50
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 49
- 239000004626 polylactic acid Substances 0.000 claims abstract description 49
- 238000002156 mixing Methods 0.000 claims abstract description 40
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims abstract description 32
- 229920002472 Starch Polymers 0.000 claims abstract description 30
- 239000008107 starch Substances 0.000 claims abstract description 30
- 235000019698 starch Nutrition 0.000 claims abstract description 29
- 239000003963 antioxidant agent Substances 0.000 claims abstract description 23
- 230000003078 antioxidant effect Effects 0.000 claims abstract description 23
- 235000006708 antioxidants Nutrition 0.000 claims abstract description 23
- 235000013808 oxidized starch Nutrition 0.000 claims abstract description 20
- 239000001254 oxidized starch Substances 0.000 claims abstract description 20
- 230000003064 anti-oxidating effect Effects 0.000 claims abstract description 18
- 235000002732 Allium cepa var. cepa Nutrition 0.000 claims abstract description 17
- 235000011389 fruit/vegetable juice Nutrition 0.000 claims abstract description 17
- ZZZCUOFIHGPKAK-UHFFFAOYSA-N D-erythro-ascorbic acid Natural products OCC1OC(=O)C(O)=C1O ZZZCUOFIHGPKAK-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229930003268 Vitamin C Natural products 0.000 claims abstract description 16
- 229930002877 anthocyanin Natural products 0.000 claims abstract description 16
- 235000010208 anthocyanin Nutrition 0.000 claims abstract description 16
- 239000004410 anthocyanin Substances 0.000 claims abstract description 16
- 150000004636 anthocyanins Chemical class 0.000 claims abstract description 16
- 235000019154 vitamin C Nutrition 0.000 claims abstract description 16
- 239000011718 vitamin C Substances 0.000 claims abstract description 16
- 239000000843 powder Substances 0.000 claims abstract description 15
- 239000000243 solution Substances 0.000 claims description 70
- 239000008367 deionised water Substances 0.000 claims description 44
- 229910021641 deionized water Inorganic materials 0.000 claims description 44
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 42
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 36
- 238000003756 stirring Methods 0.000 claims description 33
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 32
- 238000006243 chemical reaction Methods 0.000 claims description 31
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 30
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 claims description 27
- 229920000053 polysorbate 80 Polymers 0.000 claims description 27
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 24
- 238000001816 cooling Methods 0.000 claims description 24
- 239000002159 nanocrystal Substances 0.000 claims description 22
- 238000001035 drying Methods 0.000 claims description 16
- 239000004310 lactic acid Substances 0.000 claims description 16
- 235000014655 lactic acid Nutrition 0.000 claims description 16
- 229920002261 Corn starch Polymers 0.000 claims description 14
- 239000008120 corn starch Substances 0.000 claims description 14
- KSBAEPSJVUENNK-UHFFFAOYSA-L tin(ii) 2-ethylhexanoate Chemical compound [Sn+2].CCCCC(CC)C([O-])=O.CCCCC(CC)C([O-])=O KSBAEPSJVUENNK-UHFFFAOYSA-L 0.000 claims description 14
- 230000001804 emulsifying effect Effects 0.000 claims description 12
- 239000005457 ice water Substances 0.000 claims description 12
- 238000002844 melting Methods 0.000 claims description 12
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- 238000000034 method Methods 0.000 claims description 12
- 238000007789 sealing Methods 0.000 claims description 12
- 238000001291 vacuum drying Methods 0.000 claims description 12
- 238000004108 freeze drying Methods 0.000 claims description 11
- 239000003054 catalyst Substances 0.000 claims description 7
- 239000007766 cera flava Substances 0.000 claims description 4
- 239000011259 mixed solution Substances 0.000 claims description 4
- 244000068988 Glycine max Species 0.000 claims description 2
- 235000010469 Glycine max Nutrition 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 238000000967 suction filtration Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 8
- 244000291564 Allium cepa Species 0.000 claims 2
- 241000234282 Allium Species 0.000 abstract description 15
- 239000000463 material Substances 0.000 abstract description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 13
- 239000001301 oxygen Substances 0.000 abstract description 13
- 229910052760 oxygen Inorganic materials 0.000 abstract description 13
- 239000000853 adhesive Substances 0.000 abstract description 3
- 230000001070 adhesive effect Effects 0.000 abstract description 3
- 239000013078 crystal Substances 0.000 abstract description 3
- 239000002131 composite material Substances 0.000 abstract 1
- 239000006185 dispersion Substances 0.000 abstract 1
- 235000018102 proteins Nutrition 0.000 description 62
- 239000000047 product Substances 0.000 description 12
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- 239000006228 supernatant Substances 0.000 description 9
- 238000005406 washing Methods 0.000 description 9
- 230000000903 blocking effect Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
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- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 239000005871 repellent Substances 0.000 description 2
- 235000019710 soybean protein Nutrition 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 240000005020 Acaciella glauca Species 0.000 description 1
- 229920000945 Amylopectin Polymers 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 235000008582 Pinus sylvestris Nutrition 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 229920006238 degradable plastic Polymers 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000009246 food effect Effects 0.000 description 1
- 239000005003 food packaging material Substances 0.000 description 1
- 238000009920 food preservation Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000001165 hydrophobic group Chemical group 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000001839 pinus sylvestris Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
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- 229920000642 polymer Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 235000011888 snacks Nutrition 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 235000021404 traditional food Nutrition 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/10—Packing paper
-
- 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/02—Material of vegetable origin
-
- 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
-
- 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/28—Starch
-
- 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/33—Synthetic macromolecular compounds
- D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
-
- 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
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/22—Addition to the formed paper
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention relates to the technical field of food packaging, in particular to a degradable coating for food packaging paper and a preparation process thereof. According to the invention, the antioxidant layer coating liquid, the protein layer coating liquid and the hydrophobic layer coating liquid are sequentially coated on the surface of the paper-based material in a layered manner to form the degradable coating with a three-layer composite structure. Wherein the upper layer of the hydrophobic layer coating liquid is formed by mixing chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion; the protein layer coating liquid of the middle layer is a dispersion liquid of protein powder and nano starch crystals; the lower antioxidation coating liquid is in direct contact with paper-based material and is prepared by mixing oxidized starch, vitamin C, anthocyanin and onion juice. The degradable coating has strong adhesive force, can be stably attached to the surface of the paper base, effectively blocks water vapor and oxygen, and can also improve the tensile strength of the paper base material.
Description
Technical Field
The invention relates to the technical field of food packaging, in particular to a degradable coating for food packaging paper and a preparation process thereof.
Background
Traditional food packaging materials are usually produced by adopting chemical synthetic materials such as plastics, and the materials are not easy to decompose for a long time, so that the pollution to the environment is also more and more concerned. Currently, biodegradable materials are receiving more and more attention and application because of their environmental friendliness and recyclability. In the field of food packaging, paper and coatings prepared from biodegradable materials are emerging and sustainable alternatives, and are widely used in numerous products such as snack boxes, napkins, tissues, and the like.
At present, the method for preparing the biodegradable coating generally uses natural organic matters such as natural biological polymers such as chitosan, starch, protein and the like, and the unique biodegradability and biological acceptability lead the biodegradable coating to be widely applied in the fields of degradable waste treatment and the like. However, the materials have some problems after being processed into paint, such as poor moisture resistance and water resistance, poor adhesive capability and the like; therefore, there is a need to invent a novel degradable coating for food packaging paper.
Disclosure of Invention
The invention aims to provide a degradable coating for food packaging paper and a preparation process thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: a degradable coating for food packaging paper and a preparation process thereof comprise the following steps:
step 1: mixing chitosan quaternary ammonium salt, lactic acid, stannous octoate serving as a catalyst and deionized water to obtain a reaction solution, performing a sealing heating reaction, cooling, and performing suction filtration and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting Cera flava, adding Tween 80 solution, stirring, emulsifying, cooling with ice water, and ultrasonically treating to obtain Cera flava emulsion; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid, beeswax emulsion and deionized water to obtain a hydrophobic layer coating liquid;
step 3: mixing waxy corn starch and sulfuric acid solution to obtain a mixed solution; after the stirring reaction is finished, the product is washed by centrifugal water for a plurality of times, and the starch nanocrystalline is obtained by freeze drying; dispersing soybean isolated protein powder, starch nanocrystals and glycerol in deionized water, and adding sodium hydroxide to adjust the pH to 8-9 to obtain protein layer coating liquid;
step 4: mixing oxidized starch, vitamin C, anthocyanin, onion juice and deionized water to obtain an antioxidation coating liquid;
step 5: and (3) placing the food packaging paper in a sterile and dry vacuum environment, and sequentially coating and drying the antioxidant layer coating liquid, the protein layer coating liquid and the hydrophobic layer coating liquid to obtain the degradable coating for the food packaging paper.
Further, in the step 1, the contents of the components in the reaction solution are 50-60 parts by weight of chitosan quaternary ammonium salt, 70-90 parts by weight of lactic acid, 2-3 parts by weight of catalyst stannous octoate and 100-120 parts by weight of deionized water.
In the step 1, the reaction temperature is 100-120 ℃ and the reaction time is 2-3 h.
Further, in the step 2, the content of each component in the beeswax emulsion is 20-40% of beeswax and 60-80% of tween 80 solution by weight percent.
Further, in the step 2, the content of each component in the coating liquid of the hydrophobic layer is 20-35% of chitosan quaternary ammonium salt grafted polylactic acid and 65-80% of beeswax emulsion according to weight percentage.
Further, in the step 3, the content of each component in the mixed solution is 20-25 parts by weight of waxy corn starch and 100-120 parts by weight of sulfuric acid solution.
Further, in the step 3, the protein layer coating liquid contains 5-6 parts of protein powder, 3-5 parts of starch nanocrystalline, 0.5-1 part of glycerol and 90-110 parts of deionized water according to weight.
Further, in the step 4, the content of each component in the antioxidant layer coating liquid is 3-5 parts by weight of oxidized starch, 1-2 parts by weight of vitamin C, 1-1.5 parts by weight of anthocyanin, 8-17 parts by weight of onion juice and 20-25 parts by weight of deionized water.
Further, in the step 5, the coating amount of the antioxidant layer coating liquid is 12-15 g/m 2 The coating amount of the protein layer coating liquid is 5-8 g/m 2 The coating amount of the coating liquid of the hydrophobic layer is 5-8 g/m 2 。
In step 5, the drying condition is vacuum drying at 45-55 deg.c for 20-30 s.
Compared with the prior art, the invention has the following beneficial effects: in the coating prepared by the invention, the raw materials are biodegradable materials, can be decomposed under natural conditions, are nontoxic and harmless, and are friendly to the environment and human body; the coating has the functions of hydrophobicity and oxidation resistance, effectively prevents food from deteriorating, can also improve the tensile strength of food packaging paper, and has strong practicability.
In the hydrophobic layer, the polylactic acid contains a large number of hydrophobic groups C=O, and can react with hydrophilic groups-OH of the chitosan quaternary ammonium salt, so that the hydrophilicity of the chitosan quaternary ammonium salt is reduced; the chitosan quaternary ammonium salt grafted polylactic acid and beeswax are blended to obtain the hydrophobic layer coating liquid, which has good water vapor blocking effect. In the protein layer, the pH value of the coating liquid of the protein layer is controlled to be 8-9, and under the condition, the soybean protein is negatively charged, and can be better combined with quaternary ammonium salt groups in the hydrophobic layer through electrostatic action, so that the bonding force between the coatings is improved; in addition, starch nanocrystals are added into the protein layer solution, which is beneficial to improving the mechanical strength of the coating. In the antioxidation layer, the oxidized starch has stronger adhesive force, the components such as vitamin C, anthocyanin, onion juice and the like have reducibility, can effectively prevent oxygen from oxidizing food, and the onion juice also contains water-soluble fibers and bactericidal substances, so that the combination effect with paper-based fibers can be improved, and the effects of inhibiting bacteria and preventing mildew can be achieved.
It should be further noted that the use of chitosan quaternary ammonium salt has better effect than the use of chitosan. The chitosan quaternary ammonium salt is easy to dissolve in water, the hydroxyl and lactic acid are subjected to grafting reaction under the action of the catalyst, the hydrophilicity is reduced, meanwhile, the cationic quaternary ammonium salt group is reserved, and the chitosan quaternary ammonium salt can be better combined with the protein layer through the electrostatic action, so that the adhesiveness is improved; while chitosan has poor solubility, although-NH on chitosan 2 Is also positively charged and can bind to the protein layer, but during grafting, -NH 2 After reacting with lactic acid, the electropositivity of chitosan is weakened, the combination effect of the hydrophobic layer and the protein layer is reduced, and the adhesiveness and mechanical strength of the whole coating are reduced. Meanwhile, the amount of each component in the hydrophobic layer is limited. Because of the existence of quaternary ammonium salt group, chitosan quaternary ammonium salt grafted polylactic acid has stronger hydrophilicity, so when the chitosan quaternary ammonium salt grafted polylactic acid is blended with beeswax emulsion, the chitosan quaternary ammonium salt grafted polylactic acid is prepared by the following components by weightThe dosage of the water-repellent paper is controlled to be 20% -35% by percentage, and the excessive water-repellent paper can reduce the hydrophobic effect and influence the performance of the paper-based material. Although polylactic acid is recognized as a degradable plastic, the degradation speed of the polylactic acid is low in nature, and the chitosan quaternary ammonium salt grafted polylactic acid can reduce the dosage of the polylactic acid on one hand, and the chitosan quaternary ammonium salt molecules can be decomposed firstly in the degradation process, so that the effect of 'becoming zero' is realized, and the degradation speed is improved.
Furthermore, the structures of the three coatings are not randomly combined. The waterproof effect of the protein layer and the antioxidation layer is poor, and water can influence the protein layer and the antioxidation layer, so that the hydrophobic layer is used as the outermost layer for blocking water vapor. And secondly, the protein layer has an oxygen blocking effect, if the protein layer is adjusted to be positioned with the antioxidant layer, oxygen can react with the reducing substance when reaching the antioxidant layer, so that the reducing substance is rapidly consumed, the antioxidant layer is defective, the bonding effect with the protein layer is reduced, gaps are formed between the layers, infiltration of water vapor and the like further breaks down the protein layer, and finally the coating is thoroughly broken. The antioxidation layer contains oxidized starch, and is directly contacted with the paper-based material, so that the adhesion is strong; after being blocked by the protein layer, a small amount of oxygen reacts with the reducing component in the antioxidation layer, thereby avoiding the oxidation of the paper fiber.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The main materials and their sources in the following examples: the chitosan quaternary ammonium salt is from source leaf organisms, and the product number is S26618; beeswax is from the flourishing wax industry, food grade; waxy corn starch is from medium grain, and the amylopectin content is 95%; oxidized starch is from pine crown biotechnology, food grade; a4 paper is from Qinghua paper industry, 70g/m 2 The method comprises the steps of carrying out a first treatment on the surface of the The soybean protein isolate is derived from Pinus sylvestris, and is dispersed; the Tween 80 solution is a mixture of Tween 80 and water,1% of Tween 80 and 99% of deionized water by weight; the sulfuric acid solution is a mixture of sulfuric acid and water, and the concentration is 2mol/L.
Example 1
Step 1: mixing 50g of chitosan quaternary ammonium salt, 70g of lactic acid, 2g of catalyst stannous octoate and 100g of deionized water to obtain a reaction solution, sealing and reacting for 2 hours at 100 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 20% beeswax and 80% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein the hydrophobic layer coating liquid comprises 20% of chitosan quaternary ammonium salt grafted polylactic acid and 80% of beeswax emulsion by weight percent;
step 3: taking 20g of waxy corn starch and 100g of sulfuric acid solution, and stirring at 40 ℃ for 120 hours; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6, and freeze-drying to obtain starch nanocrystals; dispersing 5g of protein powder, 3g of starch nanocrystals and 0.5g of glycerol in 90g of deionized water, and adding sodium hydroxide to adjust the pH to 8 to obtain a protein layer coating solution;
step 4: mixing 3g of oxidized starch, 1g of vitamin C, 1g of anthocyanin, 8g of onion juice and 20g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Example 2
Step 1: mixing 52g of chitosan quaternary ammonium salt, 76g of lactic acid, 2g of stannous octoate serving as a catalyst and 105g of deionized water to obtain a reaction solution, sealing and reacting for 2 hours at 105 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 25% beeswax and 75% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 23% of chitosan quaternary ammonium salt grafted polylactic acid and 77% of beeswax emulsion are calculated according to weight percentage in the hydrophobic layer coating liquid;
step 3: taking 21g of waxy corn starch and 105g of sulfuric acid solution, and stirring at 40 ℃ for 130h; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6.5, and freeze-drying to obtain starch nanocrystals; dispersing 5.3g of protein powder, 3.8g of starch nanocrystals and 0.7g of glycerol in 95g of deionized water, and adding sodium hydroxide to adjust the pH to 8 to obtain a protein layer coating liquid;
step 4: mixing 3.5g of oxidized starch, 1.2g of vitamin C, 1.17g of anthocyanin, 10g of onion juice and 21g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Example 3
Step 1: mixing 54g of chitosan quaternary ammonium salt, 79g of lactic acid, 2.4g of stannous octoate serving as a catalyst and 110g of deionized water to obtain a reaction solution, sealing and reacting for 3 hours at 105 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises, by weight, 28% beeswax and 72% tween 80 solution; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 26% of chitosan quaternary ammonium salt grafted polylactic acid and 74% of beeswax emulsion are contained in the hydrophobic layer coating liquid according to weight percentage;
step 3: taking 22.5g of waxy corn starch and 110g of sulfuric acid solution, and stirring at 40 ℃ for 135 hours; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6, and freeze-drying to obtain starch nanocrystals; dispersing 5.5g of protein powder, 4.2g of starch nano-crystals and 0.78g of glycerol in 103g of deionized water, and adding sodium hydroxide to adjust the pH value to 8.5 to obtain protein layer coating liquid;
step 4: mixing 4.7g of oxidized starch, 1.6g of vitamin C, 1.3g of anthocyanin, 12g of onion juice and 23g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Example 4
Step 1: mixing 57g of chitosan quaternary ammonium salt, 82g of lactic acid, 3g of catalyst stannous octoate and 110g of deionized water to obtain a reaction solution, sealing and reacting for 2.5 hours at 110 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 35% beeswax and 65% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 28% of chitosan quaternary ammonium salt grafted polylactic acid and 72% of beeswax emulsion are contained in the hydrophobic layer coating liquid according to weight percentage;
step 3: 23g of waxy corn starch and 116g of sulfuric acid solution are taken and stirred for 135 hours at 40 ℃; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6.5, and freeze-drying to obtain starch nanocrystals; dispersing 5.8g of protein powder, 4.7g of starch nanocrystals and 0.85g of glycerol in 104g of deionized water, and adding sodium hydroxide to adjust the pH value to 9 to obtain a protein layer coating liquid;
step 4: mixing 4.3g of oxidized starch, 1.7g of vitamin C, 1.3g of anthocyanin, 13g of onion juice and 22g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Example 5
Step 1: mixing 60g of chitosan quaternary ammonium salt, 88g of lactic acid, 3g of catalyst stannous octoate and 115g of deionized water to obtain a reaction solution, sealing and reacting for 3 hours at 115 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 33% beeswax and 67% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein the hydrophobic layer coating liquid comprises, by weight, 30% of chitosan quaternary ammonium salt grafted polylactic acid and 70% of beeswax emulsion;
step 3: taking 24g of waxy corn starch and 110g of sulfuric acid solution, stirring for 145h, wherein the reaction temperature is 40 ℃; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6.5, and freeze-drying to obtain starch nanocrystals; dispersing 6g of protein powder, 4.8g of starch nanocrystals and 0.85g of glycerol in 108g of deionized water, and adding sodium hydroxide to adjust the pH value to 9 to obtain a protein layer coating solution;
step 4: mixing 5g of oxidized starch, 1g of vitamin C, 1.5g of anthocyanin, 15g of onion juice and 24g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 Sequentially coating, vacuum drying at 45deg.C for 30s after each layer is coated,the degradable coating for the food packaging paper can be obtained.
Example 6
Step 1: mixing 60g of chitosan quaternary ammonium salt, 90g of lactic acid, 3g of catalyst stannous octoate and 120g of deionized water to obtain a reaction solution, sealing and reacting for 2 hours at 120 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 40% beeswax and 60% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 35% of chitosan quaternary ammonium salt grafted polylactic acid and 65% of beeswax emulsion are calculated according to weight percentage in the hydrophobic layer coating liquid;
step 3: taking 25g of waxy corn starch and 120g of sulfuric acid solution, and stirring at 40 ℃ for 150h; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6, and freeze-drying to obtain starch nanocrystals; dispersing 6g of protein powder, 5g of starch nanocrystals and 1g of glycerol in 110g of deionized water, and adding sodium hydroxide to adjust the pH to 9 to obtain a protein layer coating solution;
step 4: mixing 5g of oxidized starch, 2g of vitamin C, 1.5g of anthocyanin, 17g of onion juice and 25g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Comparative example 1
The chitosan is used to replace chitosan quaternary ammonium salt in the hydrophobic layer coating liquid, and the rest parameters are the same as those of the example 1.
Step 1: mixing 3g of chitosan, 70g of lactic acid, 2g of catalyst stannous octoate and 100g of acetic acid solution to obtain a reaction solution, sealing and reacting for 2 hours at 100 ℃, cooling, and filtering and drying by using acetone to obtain chitosan grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 20% beeswax and 80% tween 80 solution by weight percent; mixing and stirring chitosan grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein the hydrophobic layer coating liquid comprises 20% of chitosan quaternary ammonium salt grafted polylactic acid and 80% of beeswax emulsion by weight percent;
step 3: taking 20g of waxy corn starch and 100g of sulfuric acid solution, and stirring at 40 ℃ for 120 hours; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6, and freeze-drying to obtain starch nanocrystals; dispersing 5g of protein powder, 3g of starch nanocrystals and 0.5g of glycerol in 90g of deionized water, and adding sodium hydroxide to adjust the pH to 8 to obtain a protein layer coating solution;
step 4: mixing 3g of oxidized starch, 1g of vitamin C, 1g of anthocyanin, 8g of onion juice and 20g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Comparative example 2
The content of chitosan quaternary ammonium salt grafted polylactic acid in the coating liquid of the hydrophobic layer is increased, and the rest parameters are the same as those of the example 2.
Step 1: mixing 52g of chitosan quaternary ammonium salt, 76g of lactic acid, 2g of stannous octoate serving as a catalyst and 105g of deionized water to obtain a reaction solution, sealing and reacting for 2 hours at 105 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 25% beeswax and 75% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 50% of chitosan quaternary ammonium salt grafted polylactic acid and 50% of beeswax emulsion are contained in the hydrophobic layer coating liquid according to weight percentage;
step 3: taking 21g of waxy corn starch and 105g of sulfuric acid solution, and stirring at 40 ℃ for 130h; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6.5, and freeze-drying to obtain starch nanocrystals; dispersing 5.3g of protein powder, 3.8g of starch nanocrystals and 0.7g of glycerol in 95g of deionized water, and adding sodium hydroxide to adjust the pH to 8 to obtain a protein layer coating liquid;
step 4: mixing 3.5g of oxidized starch, 1.2g of vitamin C, 1.17g of anthocyanin, 10g of onion juice and 21g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Comparative example 3
The protein layer coating solution was not added with starch nanocrystals, and the remaining parameters were the same as in example 3.
Step 1: mixing 54g of chitosan quaternary ammonium salt, 79g of lactic acid, 2.4g of stannous octoate serving as a catalyst and 110g of deionized water to obtain a reaction solution, sealing and reacting for 3 hours at 105 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises, by weight, 28% beeswax and 72% tween 80 solution; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 26% of chitosan quaternary ammonium salt grafted polylactic acid and 74% of beeswax emulsion are contained in the hydrophobic layer coating liquid according to weight percentage;
step 3: dispersing 5.5g of protein powder and 0.78g of glycerol in 103g of deionized water, and adding sodium hydroxide to adjust the pH to 8.5 to obtain protein layer coating liquid;
step 4: mixing 4.7g of oxidized starch, 1.6g of vitamin C, 1.3g of anthocyanin, 12g of onion juice and 23g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environment, and coating with antioxidant layer coating solution 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Comparative example 4
The coating order of the protein layer coating liquid and the oxidation-resistant layer coating liquid was adjusted, and the other parameters were the same as in example 4.
Step 1: mixing 57g of chitosan quaternary ammonium salt, 82g of lactic acid, 3g of catalyst stannous octoate and 110g of deionized water to obtain a reaction solution, sealing and reacting for 2.5 hours at 110 ℃, cooling, and filtering and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting beeswax, adding tween 80 solution, stirring and emulsifying for 10min, cooling with ice water, and performing ultrasonic treatment for 60s to obtain beeswax emulsion, wherein the beeswax emulsion comprises 35% beeswax and 65% tween 80 solution by weight percent; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid and beeswax emulsion to obtain a hydrophobic layer coating liquid, wherein 28% of chitosan quaternary ammonium salt grafted polylactic acid and 72% of beeswax emulsion are contained in the hydrophobic layer coating liquid according to weight percentage;
step 3: 23g of waxy corn starch and 116g of sulfuric acid solution are taken and stirred for 135 hours at 40 ℃; after the reaction is finished, centrifugally washing the product for a plurality of times until the pH value of the supernatant is 6.5, and freeze-drying to obtain starch nanocrystals; dispersing 5.8g of protein powder, 4.7g of starch nanocrystals and 0.85g of glycerol in 104g of deionized water, and adding sodium hydroxide to adjust the pH value to 9 to obtain a protein layer coating liquid;
step 4: mixing 4.3g of oxidized starch, 1.7g of vitamin C, 1.3g of anthocyanin, 13g of onion juice and 22g of deionized water to obtain an antioxidation coating liquid;
step 5: placing food packaging paper in sterile and dry vacuum environmentAccording to the coating amount of the antioxidant layer coating liquid of 12g/m 2 Coating amount of protein layer coating liquid is 5g/m 2 Coating quantity of hydrophobic layer coating liquid is 5g/m 2 And (3) coating sequentially, and vacuum drying at 45 ℃ for 30 seconds after each layer of coating is finished, so that the degradable coating for the food packaging paper can be obtained.
Experiment:
the A4 paper was double coated and performance tested as in examples 1-6 and comparative examples 1-4, wherein:
water vapor barrier properties: the water vapor transmission was measured according to the standard ASTM-E96 using a W3/062 water vapor transmission meter (weighting method), the temperature measured was (23.+ -. 0.5) DEG C and the humidity measured was (50.+ -. 1) RH.
Oxygen barrier properties: the oxygen transmission of the coated paper was measured using a Y110 oxygen transmission tester (differential pressure test) at (23.+ -. 0.1) °C, (50.+ -. 2%) RH.
The results of the experiment are shown in Table one.
Tensile strength test: stretching the sample at a constant stretching speed (20 mm/min) by a tensile tester according to the standard GB/T12914-2018 at humidity (50+ -1)% RH and temperature (30+ -1), wherein the sample width is (15+ -0.1) mm; the samples were tested again for tensile strength at humidity (90.+ -. 1)% RH, temperature (30.+ -. 1) ℃ for 120 hours.
The experimental results are shown in Table II.
List one
Watch II
Conclusion:
the data of examples 1-6 show that the degradable coating prepared by the invention is coated on a paper substrate, so that the water vapor and oxygen barrier properties of the paper material can be obviously improved. The data of example 1 and comparative example 1 show that the chitosan quaternary ammonium salt has a stronger positive charge, which is beneficial to improving the bonding strength between the hydrophobic layer and the protein layer, forming a surface coating with more stable bonding and higher strength, thereby improving the tensile strength of the paper-based material. The data of example 2 and comparative example 2 show that the effect of bonding the chitosan quaternary ammonium salt grafted polylactic acid and the protein layer is better after the content of the chitosan quaternary ammonium salt grafted polylactic acid in the hydrophobic layer is increased, but the water vapor permeability is increased and the hydrophobic performance is reduced due to the strong hydrophilicity of the chitosan quaternary ammonium salt. The data of example 3 and comparative example 3 show that the addition of nano-starch crystals has a reinforcing effect on the coating; the nano starch crystal is nontoxic and harmless, and has excellent biocompatibility and biodegradability. The data of example 4 and comparative example 4 show that the moisture resistance of the coating decreases after adjusting the coating sequence of the antioxidant layer and the protein layer; the protein layer has good oxygen blocking effect and can effectively block most of oxygen; after the protein layer is exchanged with the antioxidant layer, the protein layer is lack of blocking of the protein layer to oxygen, the reducing component in the antioxidant layer can react with oxygen, so that on one hand, the effect of food preservation cannot be achieved, on the other hand, the film layer of oxidized starch can be caused to have defects, the combination effect of the oxidized starch, the hydrophobic layer and the protein layer is reduced, further, under a humid environment, moisture enters the protein layer from the defect between the film layers, the blocking effect of the protein layer to the moisture is poor, the moisture is extremely easy to penetrate, the hydrogen bond generation effect of paper fibers is damaged, and finally the mechanical property of the paper-based material is reduced.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A preparation process of a degradable coating for food packaging paper is characterized by comprising the following steps of: the method comprises the following steps:
step 1: mixing chitosan quaternary ammonium salt, lactic acid, stannous octoate serving as a catalyst and deionized water to obtain a reaction solution, performing a sealing heating reaction, cooling, and performing suction filtration and drying by using acetone to obtain chitosan quaternary ammonium salt grafted polylactic acid;
step 2: melting Cera flava, adding Tween 80 solution, stirring, emulsifying, cooling with ice water, and ultrasonically treating to obtain Cera flava emulsion; mixing and stirring chitosan quaternary ammonium salt grafted polylactic acid, beeswax emulsion and deionized water to obtain a hydrophobic layer coating liquid;
step 3: mixing waxy corn starch and sulfuric acid solution to obtain a mixed solution; after the stirring reaction is finished, the product is washed by centrifugal water for a plurality of times, and the starch nanocrystalline is obtained by freeze drying; dispersing soybean isolated protein powder, starch nanocrystals and glycerol in deionized water, and adding sodium hydroxide to adjust the pH to 8-9 to obtain protein layer coating liquid;
step 4: mixing oxidized starch, vitamin C, anthocyanin, onion juice and deionized water to obtain an antioxidation coating liquid;
step 5: and (3) placing the food packaging paper in a sterile and dry vacuum environment, and sequentially coating and drying the antioxidant layer coating liquid, the protein layer coating liquid and the hydrophobic layer coating liquid to obtain the degradable coating for the food packaging paper.
2. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 1, the contents of the components in the reaction solution are, by weight, 50-60 parts of chitosan quaternary ammonium salt, 70-90 parts of lactic acid, 2-3 parts of catalyst stannous octoate and 100-120 parts of deionized water.
3. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 1, the reaction temperature is 100-120 ℃ and the reaction time is 2-3 h.
4. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 2, the content of each component in the beeswax emulsion is 20-40% of beeswax and 60-80% of Tween 80 solution according to weight percentage; the hydrophobic layer coating liquid contains 20-35% chitosan quaternary ammonium salt grafted polylactic acid and 65-80% beeswax emulsion by weight percent.
5. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 3, the content of each component in the mixed solution is 20-25 parts of waxy corn starch and 100-120 parts of sulfuric acid solution by weight.
6. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 3, the protein layer coating liquid comprises 5 to 6 parts of protein powder, 3 to 5 parts of starch nanocrystalline, 0.5 to 1 part of glycerol and 90 to 110 parts of deionized water according to the weight.
7. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 4, the content of each component in the antioxidant layer coating liquid is 3-5 parts of oxidized starch, 1-2 parts of vitamin C, 1-1.5 parts of anthocyanin, 8-17 parts of onion juice and 20-25 parts of deionized water by weight.
8. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 5, the coating amount of the antioxidant layer coating liquid is 12-15 g/m 2 The coating amount of the protein layer coating liquid is 5-8 g/m 2 The coating amount of the coating liquid of the hydrophobic layer is 5-8 g/m 2 。
9. The process for preparing a degradable coating for food packaging paper according to claim 1, wherein the process comprises the following steps: in the step 5, the drying condition is vacuum drying for 20-30 s at 45-55 ℃.
10. A degradable coating prepared by a preparation process of the degradable coating for food packaging paper according to any one of claims 1-9.
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| CN104928988A (en) * | 2015-05-28 | 2015-09-23 | 句容市茂源织造厂 | Natural preservative edible food packaging paper and preparation method thereof |
| CN104928987A (en) * | 2015-05-28 | 2015-09-23 | 句容市茂源织造厂 | Natural preservative degradable food packaging paper and preparation method thereof |
| CN111662457A (en) * | 2020-06-09 | 2020-09-15 | 四川大学 | Polylactic acid grafted quaternized chitosan material, stereo composite crystal nanofiber membrane thereof, and preparation methods and applications of polylactic acid grafted quaternized chitosan material and stereo composite crystal nanofiber membrane |
| US20210246333A1 (en) * | 2019-06-03 | 2021-08-12 | Board Of Trustees Of Mighigan State University | Biodegradable omniphobic and high-barrier coatings, related articles, and related methods |
| CN114059386A (en) * | 2021-11-16 | 2022-02-18 | 中国科学院理化技术研究所 | Water-based paint with waterproof and oil-proof performance and preparation method and application thereof |
| CN114892450A (en) * | 2022-06-07 | 2022-08-12 | 南通德润包装制品有限公司 | Tear-resistant hydrophobic packaging paper and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104928988A (en) * | 2015-05-28 | 2015-09-23 | 句容市茂源织造厂 | Natural preservative edible food packaging paper and preparation method thereof |
| CN104928987A (en) * | 2015-05-28 | 2015-09-23 | 句容市茂源织造厂 | Natural preservative degradable food packaging paper and preparation method thereof |
| US20210246333A1 (en) * | 2019-06-03 | 2021-08-12 | Board Of Trustees Of Mighigan State University | Biodegradable omniphobic and high-barrier coatings, related articles, and related methods |
| CN111662457A (en) * | 2020-06-09 | 2020-09-15 | 四川大学 | Polylactic acid grafted quaternized chitosan material, stereo composite crystal nanofiber membrane thereof, and preparation methods and applications of polylactic acid grafted quaternized chitosan material and stereo composite crystal nanofiber membrane |
| CN114059386A (en) * | 2021-11-16 | 2022-02-18 | 中国科学院理化技术研究所 | Water-based paint with waterproof and oil-proof performance and preparation method and application thereof |
| CN114892450A (en) * | 2022-06-07 | 2022-08-12 | 南通德润包装制品有限公司 | Tear-resistant hydrophobic packaging paper and manufacturing method thereof |
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