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CN-121991393-A - High-performance leather based on bio-based raw materials and preparation method thereof

CN121991393ACN 121991393 ACN121991393 ACN 121991393ACN-121991393-A

Abstract

The invention discloses high-performance leather based on a bio-based raw material and a preparation method thereof, and belongs to the technical field of leather. The leather is of a three-layer functionally gradient structure, and sequentially comprises a bottom layer, an intermediate foaming layer and a surface layer, wherein the bottom layer is formed by catalytic cross-linking of a thermoplastic starch matrix, vegetable tannins and activated keratin through laccase, the intermediate foaming layer is formed by thermal compression foaming of the thermoplastic starch matrix, sodium bicarbonate and citric acid, and the surface layer is formed by catalytic cross-linking of the thermoplastic starch matrix, sucrose and nanocellulose through oxidase. The preparation method comprises the steps of preparing the sizing agents of the bottom layer, the middle layer and the surface layer respectively, and then compounding and integrally hot-pressing the sizing agents by a semi-dry method. The raw materials of the invention are renewable biological base components, the preparation process is environment-friendly, the prepared leather has high tensile strength, excellent wear resistance and water resistance, tight interlayer combination, good softness and buffering property, and excellent comprehensive performance, can be widely applied to the fields of shoe materials, bags and suitcases and the like, and has good industrialization prospect.

Inventors

  • ZHANG JINCONG
  • WU YIJIAO
  • Sun Yuankang

Assignees

  • 科一(福建)超纤有限责任公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (6)

  1. 1. The high-performance leather based on the bio-based raw materials is characterized in that the leather is of a three-layer functionally gradient structure and sequentially comprises the following components from bottom to top: The bottom layer is a reinforcing layer and is formed by laccase catalyzed cross-linking of bottom layer slurry containing thermoplastic starch matrixes, vegetable tannins and activated keratin, wherein the activated keratin is keratin powder which is activated by mechanical force and is rich in free sulfhydryl groups; The middle foaming layer is a buffer layer and is arranged on the bottom layer, and is formed by hot-pressing and foaming middle layer slurry containing thermoplastic starch matrix, sodium bicarbonate and citric acid; The surface layer is a compact wear-resistant layer, is arranged on the middle foaming layer and is formed by catalytic crosslinking of surface layer slurry containing thermoplastic starch matrix, sucrose and nanocellulose through oxidase.
  2. 2. The high-performance leather based on bio-based raw materials according to claim 1, wherein the plant tannins are selected from one or more of tara tannins, wattle tannins and galli tannins, and the nanocellulose is bacterial cellulose or plant nanocellulose.
  3. 3. The high-performance leather based on biobased raw materials according to claim 1, characterized in that the thiol content of the activated keratin is >50 μmol/g.
  4. 4. A process for preparing a high-performance leather based on a bio-based raw material according to any one of claims 1 to 3, characterized in that it comprises the following steps: Step 1, preparing basic thermoplastic starch mother liquor, namely mixing corn starch, glycerol and water according to a mass ratio of 1:0.3-0.4:8-12, stirring and gelatinizing for 20-40 minutes at 80-85 ℃, and cooling to 40-45 ℃ to obtain basic thermoplastic starch mother liquor; Step 2, preparing activated keratin powder, namely washing and drying waste keratin fibers, placing the waste keratin fibers in a planetary ball mill, ball-milling the waste keratin fibers for 2-4 hours at a ball-to-material ratio of 10:1 and a rotating speed of 500-600rpm, and then sieving the waste keratin fibers with a 200-mesh sieve to obtain activated keratin powder; Step 3, preparing bottom layer slurry, namely taking 100 parts by weight of the basic thermoplastic starch mother solution in the step 1, adding 1.5-3.0 parts by weight of vegetable tannin, stirring and dissolving at 38-42 ℃, adjusting the pH value of a system to 5.0-6.5, adding laccase solution, stirring and reacting for 30-45 minutes, adding 2-5 parts by weight of activated keratin powder in the step 2, stirring and reacting at 600-800rpm for 1-2 hours, heating to 75-80 ℃ for inactivating for 10-15 minutes, and then performing vacuum defoaming to obtain the bottom layer slurry; Step 4, preparing middle foaming layer slurry, namely taking 100 parts by weight of the basic thermoplastic starch mother solution in the step 1, adding 1.0-2.0 parts by weight of glycerol, uniformly stirring, adding 1.5-3.0 parts by weight of sodium bicarbonate and 1.0-2.0 parts by weight of citric acid after premixing, stirring for 1-2 minutes, and then carrying out coating operation in the step 6 for an interval of not more than 10 minutes; step 5, preparing surface layer slurry, namely taking 100 parts by weight of the basic thermoplastic starch mother liquor in the step 1, adding 2.0-5.0 parts by weight of sucrose, stirring and dissolving at 30-40 ℃, adding oxidase solution with the dosage of 500-1000U/g sucrose, stirring and reacting for 1-2 hours, adding 0.5-2.0 parts by weight of nanocellulose, dispersing at a high speed for 10-15 minutes at 600-800rpm, and heating to 70-80 ℃ for inactivating for 10-15 minutes to obtain the surface layer slurry; Step 6, three-layer compounding and molding, namely, casting the bottom layer slurry in the step 3, drying for 20-30 minutes at 50-60 ℃ to a semi-dry state, coating the middle foaming layer slurry in the step 4 on the semi-dry bottom layer, controlling the thickness of a wet film to be 3.0-5.0mm, immediately coating the surface layer slurry in the step 5 on the middle layer, controlling the thickness of the wet film to be 0.5-1.0mm, placing the three-layer composite blank in a hot press, hot-pressing for 10-15 minutes at 150-170 ℃ and 0.2-0.5MPa, cooling, taking out, and regulating the humidity at 20-25 ℃ and 45-55% for 45-50 hours to obtain the high-performance leather based on the bio-based raw materials.
  5. 5. The method according to claim 4, wherein in step 5, the oxidase is pyranose oxidase or galactose oxidase.
  6. 6. Use of the high-performance leather based on biobased raw materials according to any one of claims 1-3 in shoe materials, bags, automotive interiors, furniture covers.

Description

High-performance leather based on bio-based raw materials and preparation method thereof Technical Field The invention relates to the technical field of leather, in particular to high-performance leather based on a bio-based raw material and a preparation method thereof. Background Leather is an important industrial material and has wide application in the fields of shoemaking, bags, automobile interiors and the like. However, the traditional animal leather tanning process relies on chemical reagents such as chromium salt and the like to generate a large amount of wastewater containing heavy metals, and the environmental pollution is serious. At present, the global leather production mainly adopts a chrome tanning process, the processing process is accompanied with high-concentration organic wastewater discharge, and the environmental treatment cost is high. To solve the above problems, polyurethane or polyvinyl chloride coated synthetic leather has once become a major alternative. The material has the cost advantage, but the petrochemical products are used as raw materials, the problem of volatile organic compound residues exists in the production process, and the volatile organic compound is difficult to naturally degrade after being abandoned, and the material is still an essentially sustainable plastic product. In recent years, bio-based leather substitutes prepared using plant wastes or microorganisms are increasingly emerging. Leather made of pineapple leaf fibers, apple leather made of apple pomace and the like continue to enter the market. However, due to the lack of the collagen fiber network structure specific to dermis, the mechanical properties of the plant source material are obviously insufficient, and the back surface of the plant source material is often required to be compounded with synthetic fiber base cloth or petroleum base components to improve the overall strength, so that the biobased content of the final product is not high. Another category of research attempts to construct biomimetic structures using mycelium or gel materials. Mycelium leather has advantages in terms of degradability, but the problems of insufficient tensile strength, poor water resistance, low process standardization degree and the like still exist at present. Although the gel-based material has the structural controllability, the gel-based material has the challenges of poor wear resistance, limited long-term stability, difficult mass production and the like. The prior art fails to provide a solution for simultaneously meeting the requirements of high mechanical strength, whole-course green preparation and adjustable structural function of the bio-based leather. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides high-performance leather based on a bio-based raw material and a preparation method thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: the utility model provides a high performance leather based on bio-based raw materials, leather is three-layer functionally gradient structure, includes from bottom to top in proper order: The bottom layer is a reinforcing layer and is formed by laccase catalyzed cross-linking of bottom layer slurry containing thermoplastic starch matrixes, vegetable tannins and activated keratin, wherein the activated keratin is keratin powder which is activated by mechanical force and is rich in free sulfhydryl groups; The middle foaming layer is a buffer layer and is arranged on the bottom layer, and is formed by hot-pressing and foaming middle layer slurry containing thermoplastic starch matrix, sodium bicarbonate and citric acid; The surface layer is a compact wear-resistant layer, is arranged on the middle foaming layer and is formed by catalytic crosslinking of surface layer slurry containing thermoplastic starch matrix, sucrose and nanocellulose through oxidase. Preferably, the plant tannin is selected from one or more of Tara tannin, vitex negundo extract and gallotannin, and the nanocellulose is bacterial cellulose or plant nanocellulose. Preferably, the activated keratin has a thiol content of > 50. Mu. Mol/g. A method of preparing high performance leather based on biobased raw materials comprising the steps of: Step 1, preparing basic thermoplastic starch mother liquor, namely mixing corn starch, glycerol and water according to a mass ratio of 1:0.3-0.4:8-12, stirring and gelatinizing for 20-40 minutes at 80-85 ℃, and cooling to 40-45 ℃ to obtain basic thermoplastic starch mother liquor; Step 2, preparing activated keratin powder, namely washing and drying waste keratin fibers, placing the waste keratin fibers in a planetary ball mill, ball-milling the waste keratin fibers for 2-4 hours at a ball-to-material ratio of 10:1 and a rotating speed of 500-600rpm, and then sieving the waste keratin fibers with a 200-mesh sieve to obtain activated keratin powder; Step 3, preparing bot