Plant protein-based leather based on gamma-polyglutamic acid crosslinking and preparation method thereof

Abstract

The invention discloses plant protein-based leather based on gamma-polyglutamic acid crosslinking and a preparation method thereof.The plant protein-based leather is prepared from plant protein, gamma-polyglutamic acid, nanocellulose, graphene oxide, plasticizer, antibacterial agent and deionized water, the content of gamma-polyglutamic acid is 10%-15%, the content of nanocellulose is 3%-5%, the content of graphene oxide is 1%-5%, the content of graphene oxide is 1%-5%, and the content of deionized water is 1%-5%. The content of the graphene oxide is 0.5%-1.5%. The nano synergistic crosslinking technology is adopted, gamma-PGA is combined with nano cellulose and graphene oxide for the first time, a three-dimensional crosslinking network is constructed, double breakthrough of mechanical property and water resistance is achieved, the preparation process is simple, the raw material cost is controllable, and the preparation method is suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of bio-based materials technology, and in particular to a plant protein-based leather based on γ-polyglutamic acid crosslinking and its preparation method. Background Technology

[0002] Traditional leather production relies on animal hides and fur, which leads to problems such as high resource consumption, severe environmental pollution (e.g., chromium tanning agent pollution), and animal welfare controversies. While plant-based protein leather offers environmental advantages as an alternative, current technologies have the following shortcomings: 1. Poor mechanical properties: The weak intermolecular forces of plant protein result in low tear strength (usually <10N / mm), which makes it difficult to meet the requirements of high-end products.

[0003] 2. Insufficient water resistance: It easily swells and deforms when exposed to water, and there is limited room for improvement in water resistance (usually less than 30%). Summary of the Invention

[0004] This invention provides a plant protein-based leather based on γ-polyglutamic acid crosslinking and its preparation method, in order to solve the problems mentioned in the background art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A plant protein-based leather based on γ-polyglutamic acid crosslinking, the plant protein-based leather is made of plant protein, γ-polyglutamic acid, nanocellulose, graphene oxide, plasticizer, antibacterial agent and deionized water, wherein the content of γ-polyglutamic acid is 10%-15%, the content of nanocellulose is 3%-5% and the content of graphene oxide is 0.5%-1.5%.

[0006] As a further improvement to this technical solution: the plant protein is soybean protein or wheat protein, with a content of 55%-65%.

[0007] As a further improvement to this technical solution: the plasticizer is glycerin or sorbitol, with a content of 5%-10%.

[0008] As a further improvement to this technical solution: the antibacterial agent is silver ions or chitosan, with a content of 1%-3%.

[0009] As a further improvement to this technical solution: the nanocellulose is subjected to TEMPO oxidation treatment to introduce carboxyl groups on its surface.

[0010] As a further improvement to this technical solution: the graphene oxide is synthesized by the Hummers method and dispersed in water to form a stable colloid with a concentration of 1 mg / mL.

[0011] This invention also proposes a method for preparing plant protein-based leather based on γ-polyglutamic acid crosslinking, comprising the following steps: The first step is the pretreatment of nanomaterials: TEMPO oxidation is performed on nanocellulose to introduce carboxyl groups on its surface, thereby improving its interaction with γ-PGA; for graphene oxide, after synthesis using the Hummers method, it is dispersed in water to form a stable colloid with a concentration controlled at about 1 mg / mL. The second step is the preparation of the premix: plant protein, γ-PGA, treated nanocellulose, and graphene oxide colloid are added to deionized water in proportion and stirred at high speed to form a uniform dispersion. Then, plasticizer and antibacterial agent are added. The third step, film formation and crosslinking: The premix is ​​coated onto the surface of the release paper, with the coating thickness controlled at 0.6-1.2 mm. Then, a hot-pressing treatment is performed at a temperature of 130℃, a pressure of 6 MPa, and a time of 15 minutes to promote the crosslinking reaction. The fourth step is post-processing: After hot pressing, the material is cooled to room temperature, the release paper is peeled off, and the material is placed in a constant temperature and humidity chamber and cured for 72 hours at 25°C and 60% RH. Finally, an antibacterial agent is coated on the surface, and the finished product is obtained after drying.

[0012] As a further improvement to this technical solution: In the second step, during the preparation of the premix, the stirring speed of the premix is ​​1200 rpm, the stirring time is 15 minutes, and the viscosity is stabilized at 8000-12000 cP.

[0013] As a further improvement to this technical solution: the water absorption rate of the plant protein-based leather is <10%, and the tear strength is >21 N / mm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention employs nano-synergistic crosslinking technology, combining γ-PGA with dual nanomaterials (nanocellulose + graphene oxide) for the first time to construct a three-dimensional crosslinking network, achieving a dual breakthrough in mechanical properties and water resistance. Furthermore, the preparation process is simple, the raw material cost is controllable, and it is suitable for large-scale production.

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a method for preparing plant protein-based leather based on γ-polyglutamic acid crosslinking proposed in this invention. Detailed Implementation

[0017] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] Example 1 A formulation for plant protein-based leather based on γ-polyglutamic acid crosslinking is as follows: 60% soybean protein, 12% γ-PGA, 4% nanocellulose, 1% graphene oxide, 8% plasticizer, 1% antibacterial agent, and the balance being deionized water; wherein, the plant protein is soybean protein or wheat protein, the plasticizer is glycerol or sorbitol, the antibacterial agent is silver ions or chitosan, the nanocellulose is oxidized by TEMPO to introduce carboxyl groups on the surface, and the graphene oxide is synthesized by the Hummers method and dispersed in water to form a stable colloid with a concentration of 1 mg / mL.

[0020] The preparation method of this plant protein-based leather: The first step is the pretreatment of nanomaterials: TEMPO oxidation is performed on nanocellulose to introduce carboxyl groups on its surface, thereby improving its interaction with γ-PGA; for graphene oxide, after synthesis using the Hummers method, it is dispersed in water to form a stable colloid with a concentration controlled at about 1 mg / mL.

[0021] The second step is the preparation of the premix: plant protein, γ-PGA, treated nanocellulose, and graphene oxide colloid are added to deionized water in a certain proportion and stirred in a high-speed stirrer at 1200 rpm for 15 minutes to form a uniform dispersion. Then, plasticizer and antibacterial agent are added, and stirring is continued until the viscosity stabilizes at 8000-12000 cP.

[0022] The third step, film formation and crosslinking: The premix is ​​coated onto the surface of the release paper, with the coating thickness controlled at 0.6-1.2 mm. Then, a hot-pressing treatment is performed at a temperature of 130℃, a pressure of 6 MPa, and a time of 15 minutes to promote the crosslinking reaction.

[0023] The fourth step is post-processing: After hot pressing, the material is cooled to room temperature, the release paper is peeled off, and the material is placed in a constant temperature and humidity chamber and cured for 72 hours at 25°C and 60% RH. Finally, an antibacterial agent is coated on the surface, and the finished product is obtained after drying.

[0024] Example 2 Example 2 differs from Example 1 in that the formulation of a plant protein-based leather based on γ-polyglutamic acid crosslinking is as follows: 55% soybean protein, 10% γ-PGA, 3% nanocellulose, 0.5% graphene oxide, 5% plasticizer, 1% antibacterial agent, and the balance being deionized water.

[0025] Example 3 Example 3 differs from Example 1 in that the formulation of a plant protein-based leather based on γ-polyglutamic acid crosslinking is as follows: 65% soybean protein, 15% γ-PGA, 5% nanocellulose, 1.5% graphene oxide, 10% plasticizer, 3% antibacterial agent, and the balance being deionized water.

[0026] Comparative Example 1 (with only nanocellulose added) The formulation of Comparative Example 1 is as follows: 60% soybean protein, 12% γ-PGA, 4% nanocellulose, 8% plasticizer, 1% antibacterial agent, and the balance is deionized water.

[0027] Preparation method: Same as Example 1, but without adding graphene oxide.

[0028] Comparative Example 2 (graphene oxide only) Formula: 60% soy protein, 12% γ-PGA, 1% graphene oxide, 8% plasticizer, 1% antibacterial agent, and the remainder is deionized water.

[0029] Preparation method: Same as Example 1, but without adding nanocellulose.

[0030] Comparative Example 3 (without γ-PGA) Formula: 60% soybean protein, 4% nanocellulose, 1% graphene oxide, 8% plasticizer, 1% antibacterial agent, and the remainder is deionized water.

[0031] Preparation method: Same as in real-time example 1, but without the addition of γ-PGA.

[0032]

[0033] The experimental comparison table clearly shows that Examples 1, 2, and 3 outperformed Comparative Examples 1, 2, and 3 in terms of tear strength and water absorption, verifying the effectiveness of the dual-nano synergistic crosslinking technology.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A plant protein-based leather based on γ-polyglutamic acid crosslinking, characterized in that, This plant protein-based leather is made from plant protein, γ-polyglutamic acid, nanocellulose, graphene oxide, plasticizer, antibacterial agent and deionized water, wherein the content of γ-polyglutamic acid is 10%-15%, the content of nanocellulose is 3%-5% and the content of graphene oxide is 0.5%-1.5%.

2. The plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 1, characterized in that, The plant protein is soybean protein or wheat protein, with a content of 55%-65%.

3. The plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 2, characterized in that, The plasticizer is glycerin or sorbitol, with a content of 5%-10%.

4. The plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 3, characterized in that, The antibacterial agent is silver ions or chitosan, with a content of 1%-3%.

5. The plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 4, characterized in that, The nanocellulose is subjected to TEMPO oxidation treatment, which introduces carboxyl groups onto its surface.

6. The plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 5, characterized in that, The graphene oxide was synthesized via the Hummers method and dispersed in water to form a stable colloid with a concentration of 1 mg / mL.

7. A method for preparing plant protein-based leather based on γ-polyglutamic acid crosslinking according to any one of claims 1-6, characterized in that, Includes the following steps: The first step is the pretreatment of nanomaterials: TEMPO oxidation is performed on nanocellulose to introduce carboxyl groups on its surface, thereby improving its interaction with γ-PGA; for graphene oxide, after synthesis using the Hummers method, it is dispersed in water to form a stable colloid with a concentration controlled at about 1 mg / mL. The second step is the preparation of the premix: plant protein, γ-PGA, treated nanocellulose, and graphene oxide colloid are added to deionized water in proportion and stirred at high speed to form a uniform dispersion. Then, plasticizer and antibacterial agent are added. The third step, film formation and crosslinking: The premix is ​​coated onto the surface of the release paper, with the coating thickness controlled at 0.6-1.2 mm. Then, a hot-pressing treatment is performed at a temperature of 130℃, a pressure of 6 MPa, and a time of 15 minutes to promote the crosslinking reaction. The fourth step is post-processing: After hot pressing, the material is cooled to room temperature, the release paper is peeled off, and the material is placed in a constant temperature and humidity chamber and cured for 72 hours at 25°C and 60% RH. Finally, an antibacterial agent is coated on the surface, and the finished product is obtained after drying.

8. The method for preparing plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 7, characterized in that, In the second step, during the preparation of the premix, the stirring speed of the premix is ​​1200 rpm, the stirring time is 15 minutes, and the viscosity is stabilized at 8000-12000 cP.

9. The method for preparing plant protein-based leather based on γ-polyglutamic acid crosslinking according to claim 8, characterized in that, The plant protein-based leather has a water absorption rate of <10% and a tear strength of >21 N / mm.

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