CN116042176A - Vegetable protein adhesive and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of molecular materials, in particular to a vegetable protein adhesive and a preparation method and application thereof. The vegetable protein adhesive comprises the following components: vegetable proteins, proteases, catalysts, cysteines and calcium phosphate mineralized in situ; the mass ratio of the vegetable protein, the cysteine and the calcium phosphate which is mineralized in situ is (10-25): (2-10): (0.1-1). The organic-inorganic hybrid adhesive grafted with cysteine is formed through amidation reaction and in-situ mineralization of calcium phosphate, and has strong cohesive force, strong interfacial interaction with wood and high bonding strength. The adhesive provided by the invention has higher water resistance, mildew-proof antibacterial property, flame retardance and artificial board recycling property.

Description

Vegetable protein adhesive and preparation method and application thereof

Technical Field

The invention relates to the technical field of molecular materials, in particular to a vegetable protein adhesive and a preparation method and application thereof.

Background

The artificial board is widely applied to the fields of indoor decoration, furniture, buildings and the like. At the same time, a large amount of waste artificial boards and their products are produced each year. At present, the mode of treating the waste artificial boards in the prior art mainly comprises landfill and incineration, and only a small part of the waste artificial boards are recycled. However, the artificial board and the products thereof contain chemical raw materials such as urea-formaldehyde resin, phenolic resin and the like, and the landfill treatment not only occupies land and increases transportation cost, but also can pollute soil, water source and harm the environment if the treatment is improper. Harmful gases generated by the combustion process also pollute the atmosphere. In addition, the aldehyde-based adhesive is difficult to recycle the artificial board.

The vegetable protein adhesive has the advantages of rich raw materials, reproducibility, biodegradability and the like, and becomes the most promising adhesive for replacing aldehyde resin in large scale in the artificial board industry. However, vegetable protein adhesives are generally low in mechanical properties, limiting their large-scale application.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a vegetable protein adhesive, and a preparation method and application thereof. The organic-inorganic hybrid system grafted with cysteine is formed through amidation reaction and in-situ mineralization of calcium phosphate, so that the bonding strength of the adhesive is remarkably improved.

In a first aspect, the present invention provides a vegetable protein adhesive comprising: vegetable proteins, proteases, catalysts, cysteines and calcium phosphate mineralized in situ;

the mass ratio of the vegetable protein, the cysteine and the calcium phosphate which is mineralized in situ is (10-25): (2-10): (0.1-1).

The invention is inspired by the keratin structure, and simultaneously adopts cysteine modified and in-situ mineralized calcium phosphate to prepare the organic-inorganic hybrid plant protein adhesive, which remarkably improves cohesive force, and simultaneously remarkably improves water-resistant cementing property, and introduces a large amount of mercaptan bonds to be beneficial to disulfide bond formation. Further, the vegetable protein adhesive comprises the following components in parts by weight:

15-20 parts of vegetable protein, 3-5 parts of cysteine and 0.3-0.7 part of calcium phosphate mineralized in situ.

Further, the vegetable protein adhesive comprises the following components in parts by weight:

15 to 20 parts of vegetable protein, 0.1 to 0.3 part of protease, 0.5 to 1 part of catalyst, 3 to 5 parts of cysteine and 0.3 to 0.7 part of calcium phosphate mineralized in situ.

Further, the protease comprises: one or more of alkaline protease, pepsin, papain or bromelain, preferably bromelain; the catalyst includes EDC and NHS.

Further, the mass ratio of EDC to NHS is (3-7): 1.

EDC: (1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride), NHS: n-hydroxysuccinimide.

Further, the method further comprises the following steps: a molecular modifier and sodium tetraborate.

Further, the mass ratio of the molecular modifier to sodium tetraborate is (6-10): 1.

According to the invention, a molecular modifier and sodium tetraborate are further introduced into the adhesive system, the diol exposed by the ring-opening reaction of the molecular modifier and the enzymolysis protein and the sodium tetraborate form a dynamic borate bond, and the application of the adhesive in the recycling of the artificial board is improved in cooperation with the dynamic disulfide bond.

Further, the calcium phosphate subjected to in-situ mineralization is prepared by the following method:

mixing a calcium chloride solution and a dipotassium hydrogen phosphate solution, and then adding the mixture into a system of the plant protein adhesive; the mass ratio of the calcium chloride in the calcium chloride solution to the dipotassium hydrogen phosphate in the dipotassium hydrogen phosphate solution is (2.5-3.5): (1.2-2.4).

Further, the plant protein comprises: one or more of water-soluble soybean, peanut or cottonseed isolated proteins.

As a preferred embodiment, the present invention provides a vegetable protein adhesive comprising:

15 to 20 parts of vegetable protein, 0.1 to 0.3 part of protease, 0.5 to 1 part of catalyst, 3 to 5 parts of cysteine, 0.3 to 0.7 part of calcium phosphate mineralized in situ, 3 to 6 parts of molecular modifier and 0.5 to 1 part of sodium tetraborate.

In a second aspect, the invention provides a preparation method of a vegetable protein adhesive, comprising the following steps:

the plant protein is subjected to enzymolysis by adopting protease to obtain plant protein enzymolysis dispersion liquid; mixing the plant proteolytic dispersion liquid, cysteine and a catalyst; further mixing a molecular modifier and sodium tetraborate to obtain an adhesive mixture; a calcium chloride solution and a dimethyl hydrogen phosphate solution are added to the adhesive mixture.

Further, the enzymatic hydrolysis includes: enzymolysis is carried out for 10 to 15 minutes at 50 to 60 ℃;

mixing the plant protein enzymolysis dispersion liquid, cysteine and a catalyst, and then uniformly mixing for 5-8 hours;

the molecular modifier and sodium tetraborate are mixed uniformly for 20-30 minutes;

and adding the calcium chloride solution and the dimethyl hydrogen phosphate solution into the adhesive mixture, and uniformly mixing for 20-30 minutes.

The invention has the following effects:

according to the invention, an organic-inorganic hybrid system grafted with cysteine is formed through amidation reaction and in-situ mineralization of calcium phosphate, so that the cohesive force of the adhesive is obviously improved. Meanwhile, the molecular modifier and sodium tetraborate are introduced, so that the adhesive can be applied to artificial board recycling; and the bonding strength is further improved.

The prepared plant protein adhesive is environment-friendly, has no harmful substance release, has good water resistance, strong interfacial interaction with wood, mildew resistance, antibacterial property and flame retardance, and can effectively promote the practical application of the plant protein adhesive and the recycling of artificial boards.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are 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.

Example 1

The embodiment provides a preparation method of a multifunctional plant protein adhesive, which comprises the following raw materials in parts by weight:

wherein the dispersion medium is deionized water, the molecular modifier is glycidol, and the vegetable protein is soybean protein isolate.

The specific processing flow is as follows:

(1) The components are weighed according to the weight ratio, vegetable protein and bromelain are dispersed in deionized water and stirred for 10min at 55 ℃, and then the mixture is transferred to a water bath kettle at 100 ℃ and placed for 5min to inactivate bromelain.

(2) Uniformly dispersing L-cysteine and catalysts (EDC and NHS) in the plant proteolytic dispersion liquid obtained in the step (1), and stirring for 6h.

(3) Uniformly dispersing the molecular modifier and sodium tetraborate in the dispersion liquid obtained in the step (2), and stirring for 20min at room temperature.

(4) And (3) respectively adding the calcium chloride solution and the dipotassium hydrogen phosphate solution into the adhesive mixture in the step (3), and stirring for 20min at room temperature to obtain the adhesive deposited by the calcium phosphate.

Example 2

The embodiment provides a preparation method of a multifunctional plant protein adhesive, which comprises the following raw materials in parts by weight:

wherein the dispersion medium is deionized water, the molecular modifier is glycidol, and the vegetable protein is soybean protein isolate.

The specific process flow was the same as in example 1.

Test example 1

The adhesive prepared in examples 1-2 and a plurality of control groups was used for further preparation of three-layer plywood for adhesive strength test.

Control group 1: 15g of vegetable protein and 70g of deionized water are used. Accordingly, the vegetable proteins were directly dispersed in deionized water.

Control group 2: 15g of vegetable protein, 0.1g of bromelain and 70g of deionized water are used. Accordingly, only the enzymolysis flow of the step (1) in the embodiment is carried out.

Control group 3: 15g of vegetable protein, 0.1g of bromelain, catalyst (EDC: NHS=0.5:0.1 g), 3g of L-cysteine and 66.3g of deionized water are used. Accordingly, only the enzymatic hydrolysis of step (1) and the mixed cysteine procedure of step (2) in the examples were performed.

Control group 4: 15g of vegetable protein, 0.1g of bromelain, catalyst (EDC: NHS=0.5:0.1 g), 3g of L-cysteine, 5g of molecular modifier and 61.3g of deionized water. Accordingly, only the enzymatic hydrolysis of step (1) and the mixing of cysteines of step (2), and step (3) of the examples were performed, but only the molecular modifier was dispersed in the mixture.

Control group 5: and melamine modified urea formaldehyde resin (grade E0) with a F/U molar ratio of 1.01 was purchased from Shandong Qianson Wood Co.

Control group 6: 15g of vegetable protein, 0.1g of bromelain, catalyst (EDC: NHS=0.5:0.1 g), 3g of L-cysteine, 0.3g of calcium chloride, 0.2g of dipotassium hydrogen phosphate and 65.8g of deionized water. Accordingly, only steps (1), (2) and (4) of the examples were performed.

Control group 7: 15g of vegetable protein, 0.1g of bromelain, 5g of molecular modifier, 0.6g of sodium tetraborate and 64.3g of deionized water. Accordingly, only the enzymolysis step of the step (1) and the treatment flow of the step (3) in the embodiment are carried out.

The test method is as follows:

1. intensity test

Poplar veneer: drying the water content to 12%; dimensions 40cm x 0.15cm.

The preparation process is as follows:

sizing: the glue coating amount is 180g/m ² 。

Pressure, temperature, time: 1MPa,120 ℃ and 6min.

The performance of the transverse spliced product is detected according to the detection method of GB/T17657-1999 artificial board and decorative artificial board physical and chemical Property experiment method.

2. The mildew resistance test is as follows:

15g of the synthetic adhesive were transferred to a petri dish and then stored in a constant temperature and humidity cabinet having a relative humidity of 50% and a temperature of 30 ℃.

3. Antibacterial activity tests on staphylococcus aureus and escherichia coli were performed by using the adhesives of examples 1-2 and control groups 1-7 of the present invention, respectively.

4. And (3) recycling and testing the artificial board:

the plywood made with the adhesives of examples 1-2 and control 1-7, respectively, was crushed into pieces. Then, the adhesives of comparative examples 1 to 7 and examples 1 to 2 were reapplied, respectively, to prepare a particle board according to the following normal preparation process:

sizing: the sizing amount was 14%.

Pressure, temperature, time: 3MPa,180 ℃ and 6min.

The breaking Modulus (MOR), the elastic Modulus (MOE) and the internal adhesive strength (IB) of the shaving board product are detected according to the GB/T17657-2013 method for testing the physicochemical properties of the artificial board and the decorative artificial board.

5. Test results

The test results are shown in the following table:

TABLE 1 comprehensive Properties of plant protein adhesives

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The vegetable protein adhesive is characterized by comprising the following components: vegetable proteins, proteases, catalysts, cysteines and calcium phosphate mineralized in situ;

the mass ratio of the vegetable protein, the cysteine and the calcium phosphate which is mineralized in situ is (10-25): (2-10): (0.1-1).

2. The vegetable protein adhesive according to claim 1, wherein the vegetable protein adhesive comprises, in parts by weight:

15-20 parts of vegetable protein, 3-5 parts of cysteine and 0.3-0.7 part of calcium phosphate mineralized in situ.

3. The vegetable protein adhesive according to claim 2, wherein the vegetable protein adhesive comprises, in parts by weight:

15 to 20 parts of vegetable protein, 0.1 to 0.3 part of protease, 0.5 to 1 part of catalyst, 3 to 5 parts of cysteine and 0.3 to 0.7 part of calcium phosphate mineralized in situ.

4. A vegetable protein adhesive according to claim 3, wherein the protease comprises: one or more of alkaline protease, pepsin, papain, or bromelain, preferably bromelain; and/or, the catalyst includes EDC and NHS.

5. The vegetable protein adhesive of any one of claims 1-4, further comprising: a molecular modifier and sodium tetraborate.

6. The vegetable protein adhesive according to claim 1, wherein the in-situ mineralized calcium phosphate is prepared by the following method:

mixing a calcium chloride solution and a dipotassium hydrogen phosphate solution, and then adding the mixture into a system of the plant protein adhesive; the mass ratio of the calcium chloride in the calcium chloride solution to the dipotassium hydrogen phosphate in the dipotassium hydrogen phosphate solution is (2.5-3.5): (1.2-2.4).

7. The vegetable protein adhesive according to claim 1, comprising, in parts by weight:

15 to 20 parts of vegetable protein, 0.1 to 0.3 part of protease, 0.5 to 1 part of catalyst, 3 to 5 parts of cysteine, 0.3 to 0.7 part of calcium phosphate mineralized in situ, 3 to 6 parts of molecular modifier and 0.5 to 1 part of sodium tetraborate.

8. The vegetable protein adhesive of any one of claims 1-7, wherein the vegetable protein comprises: one or more of water-soluble soybean, peanut or cottonseed isolated proteins.

9. The method for preparing the vegetable protein adhesive according to any one of claims 1 to 8, comprising the steps of:

the plant protein is subjected to enzymolysis by adopting protease to obtain plant protein enzymolysis dispersion liquid; mixing the plant proteolytic dispersion liquid, cysteine and a catalyst; further mixing a molecular modifier and sodium tetraborate to obtain an adhesive mixture; a calcium chloride solution and a dimethyl hydrogen phosphate solution are added to the adhesive mixture.

10. The method according to claim 9, wherein,

the enzymolysis comprises the following steps: enzymolysis is carried out for 10 to 15 minutes at 50 to 60 ℃; and/or

Mixing the plant protein enzymolysis dispersion liquid, cysteine and a catalyst, and then uniformly mixing for 5-8 hours; and/or

The molecular modifier and sodium tetraborate are mixed uniformly for 20-30 minutes; and/or the number of the groups of groups,

and adding the calcium chloride solution and the dimethyl hydrogen phosphate solution into the adhesive mixture, and uniformly mixing for 20-30 minutes.