A sustainable water-resistant mildew-proof soy protein adhesive and a preparation method thereof

Abstract

The present application relates to a kind of sustainable water-resistant mold-resistant soy protein adhesive and its preparation method, belong to soy protein adhesive technical field.The sustainable water-resistant mold-resistant soy protein adhesive is composed of the following mass fraction of raw materials: 15-35 parts of soybean meal, 55-75 parts of water, 2-6 parts of crosslinking agent, 0.1-0.5 parts of sodium carboxymethyl cellulose, 0.5-2 parts of lauroyl arginine ethyl ester hydrochloride.The present application introduces sodium carboxymethyl cellulose, lauroyl arginine ethyl ester hydrochloride and crosslinking agent into soybean meal system, and prepares a kind of sustainable water-resistant mold-resistant soy protein adhesive.Lauroyl arginine ethyl ester hydrochloride forms high-specificity guanidino carboxylate bridge hydrogen bond with soybean meal and sodium carboxymethyl cellulose respectively, which leads to the formation of heterogeneous structure in the system, thereby improving internal energy dissipation, further improving the toughness and water resistance of adhesive.At the same time, thanks to the broad-spectrum antibacterial property of lauroyl arginine ethyl ester hydrochloride, the adhesive has good preservative and antibacterial effect.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of sustainable water-resistant mold-resistant soy protein adhesive and its preparation method, belong to soy protein adhesive technical field. BACKGROUND

[0002] With the enhancement of people's environmental awareness and the improvement of laws and regulations, traditional adhesives are mostly derived from non-renewable resources such as petroleum, which can exacerbate the shortage of petroleum resources and environmental degradation during production and use, and the release of toxic gases seriously endangers people's health, which is difficult to meet the actual demand. Therefore, it is urgent to develop green and environmentally friendly bio-based adhesives to replace traditional petroleum-based adhesives.

[0003] As a byproduct of soybean processing, soybean meal has the advantages of wide raw material sources, easy processing and biodegradability, and has attracted widespread attention from the wood-based panel industry. However, pure protein adhesives have poor water resistance and are easily eroded by microorganisms, which limits their further development. Chemical modification is considered the most effective method to improve the performance of soy protein adhesives. The introduction of substances such as sodium dodecyl sulfate, polyamide epoxy chloropropane, polyurethane, and acrylic acid can greatly improve the performance of soy protein adhesives and to some extent avoid the release of formaldehyde gas. However, the above substances can have some impact on the environment during production or discharge, and are not completely green and environmentally friendly.

[0004] Therefore, it is urgent to find a more green and environmentally friendly method to improve the water resistance and mold resistance of adhesives in order to promote the early large-scale industrial production of soy protein adhesives. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides a kind of sustainable water-resistant mold-resistant soy protein adhesive and its preparation method.

[0006] The technical solution of the present application is as follows:

[0007] A kind of sustainable water-resistant mold-resistant soy protein adhesive, which is composed of the following mass fractions of raw materials: soybean meal 15-35 parts, water 55-75 parts, crosslinking agent 2-6 parts, sodium carboxymethyl cellulose 0.1-0.5 parts, lauroyl arginine ethyl ester hydrochloride 0.5-2 parts.

[0008] According to the present application, the soybean protein content in the soybean meal is preferably 45-50%, and the fineness is 75-85 mesh.

[0009] According to the present application, the crosslinking agent is preferably triepoxy glycidyl amine or ethylene glycol diglycidyl ether.

[0010] According to the present application, the mass of the crosslinking agent is 2-6% of the sum of the mass of the soybean meal and water.

[0011] According to the application, preferably, the sodium carboxymethyl cellulose has a mass of 0.1-0.2% of the sum of the mass of the soybean meal and the mass of the water.

[0012] According to the application, preferably, the lauroyl arginine ethyl ester hydrochloride has a mass of 0.5-2% of the sum of the mass of the soybean meal and the mass of the water.

[0013] According to the application, preferably, the sustainable water-resistant and mildew-resistant soybean protein adhesive is composed of the following raw materials in mass fraction: 28 parts of soybean meal, 72 parts of water, 4 parts of crosslinking agent, 0.15 parts of sodium carboxymethyl cellulose and 1 part of lauroyl arginine ethyl ester hydrochloride.

[0014] Among them, the crosslinking agent has a mass of 4% of the sum of the mass of the soybean meal and the mass of the water, the lauroyl arginine ethyl ester hydrochloride has a mass of 1% of the sum of the mass of the soybean meal and the mass of the water, and the sodium carboxymethyl cellulose has a mass of 0.15% of the sum of the mass of the soybean meal and the mass of the water.

[0015] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive comprises the following steps:

[0016] (1) According to the proportion, the sodium carboxymethyl cellulose and the lauroyl arginine ethyl ester hydrochloride are respectively dissolved in water, stirred uniformly, mixed, and a compound solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride is obtained;

[0017] (2) According to the proportion, the soybean meal and the crosslinking agent are added to the compound solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride obtained in step (1), and mechanically stirred uniformly to obtain the sustainable water-resistant and mildew-resistant soybean protein adhesive.

[0018] The sustainable water-resistant and mildew-resistant soybean protein adhesive is applied to wood processing and artificial board.

[0019] In the application, the “%” not specifically explained is the mass percentage.

[0020] The technical features and beneficial effects of the application are as follows:

[0021] 1、The present application ingeniously utilizes the biological-based electrical difference by introducing sodium carboxymethyl cellulose, lauroyl arginine ethyl ester hydrochloride and a crosslinking agent into the soybean meal system, and a sustainable water-resistant mold-resistant soy protein adhesive is prepared by adjusting multiple actions such as electrostatic adsorption, salt bridge hydrogen bond and covalent bond combination. The lauroyl arginine ethyl ester hydrochloride can be attracted by the electrostatic action with the negatively charged sodium carboxymethyl cellulose, and the guanidino group on the structure thereof forms a salt bridge hydrogen bond with the active groups on the soybean meal and sodium carboxymethyl cellulose, respectively, to produce a non-uniform hierarchical structure, improve the network interweaving density and energy dissipation of the whole system, and thus improve the bonding strength. And the present application further improves the water resistance of the adhesive by using the crosslinking agent to form a covalent bond with the soybean meal through ring-opening reaction.

[0022] 2、The main raw materials used in the present application, soybean meal, sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride, are all biological-based materials or their derivatives, which are green, environmentally friendly and biodegradable, and meet the concept of green and sustainable development. In addition, lauroyl arginine ethyl ester hydrochloride, as a cationic surfactant, can change the permeability of cell membranes, and has a significant inhibitory effect on bacteria, yeast, mold and other microorganisms, and has good preservative and antibacterial effect.

[0023] 3、The sustainable water-resistant mold-resistant soy protein adhesive of the present application has simple process, is non-toxic and harmless, and has stable performance, and can be applied in wood processing and artificial board, and the produced plywood meets the requirements of national second-class plywood. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is the result graph of the preservative experiment in the test example.

[0025] Figure 2 It is the result graph of the antibacterial experiment in the test example. DETAILED DESCRIPTION

[0026] The technical solutions of the present application are further described below by examples. It should be noted that the following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0027] The soybean meal used in the following examples has a soybean protein content of 47% and a fineness of 80 mesh, which is purchased from Shandong Yuwang Group.

[0028] Ethylene glycol diglycidyl ether, sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride are purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.

[0029] The crosslinking agent triglycidylamine described in the examples was prepared according to the method reported in the published document “Triglycidylamine crosslinking of porcine aortic valve cusps or bovine pericardium results in improved biocompatibility, biomechanics, and calcification resistance: chemical and biological mechanisms”.

[0030] Example 1

[0031] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by weight: 28 g soybean meal, 72 g water, 2 g triglycidylamine, 0.15 g sodium carboxymethyl cellulose, and 0.5 g lauroyl arginine ethyl ester hydrochloride.

[0032] The specific preparation method of the sustainable water-resistant and mildew-resistant soy protein adhesive is as follows:

[0033] (1) dissolving sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride in water according to a ratio, stirring and mixing, and obtaining a composite solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride;

[0034] (2) adding soybean meal and triglycidylamine to the composite solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride obtained in step (1) according to the ratio, and mechanically stirring the mixture to obtain a sustainable water-resistant and mildew-proof soybean protein adhesive.

[0035] Example 2

[0036] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by weight: 28 g soybean meal, 72 g water, 2 g ethylene glycol diglycidyl ether, 0.15 g sodium carboxymethyl cellulose, and 0.5 g lauroyl arginine ethyl ester hydrochloride.

[0037] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive in this embodiment is the same as that in Example 1.

[0038] Example 3

[0039] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by weight: 28 g soybean meal, 72 g water, 4 g triglycidylamine, 0.15 g sodium carboxymethyl cellulose, and 0.5 g lauroyl arginine ethyl ester hydrochloride.

[0040] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive in this embodiment is the same as that in Example 1.

[0041] Example 4

[0042] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by weight: 28 g soybean meal, 72 g water, 6 g triglycidylamine, 0.15 g sodium carboxymethyl cellulose, and 0.5 g lauroyl arginine ethyl ester hydrochloride.

[0043] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive in this embodiment is the same as that in Example 1.

[0044] Example 5

[0045] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by weight: 28 g soybean meal, 72 g water, 4 g triglycidylamine, 0.15 g sodium carboxymethyl cellulose, and 1 g lauroyl arginine ethyl ester hydrochloride.

[0046] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive in this embodiment is the same as that in Example 1.

[0047] Example 6

[0048] A sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by mass: 28 g soybean meal, 72 g water, 4 g triglycidylamine, 0.15 g sodium carboxymethyl cellulose, and 2 g lauroyl arginine ethyl ester hydrochloride.

[0049] The preparation method of the sustainable water-resistant and mildew-resistant soybean protein adhesive in this embodiment is the same as that in Example 1.

[0050] Comparative Example 1

[0051] A soybean protein adhesive is composed of the following raw materials in parts by mass: 28g soybean meal and 72g water.

[0052] The soy protein adhesive in this comparative example was prepared according to the following method: soybean meal was added to water according to a certain ratio, and the mixture was mechanically stirred to obtain the soy protein adhesive.

[0053] Comparative Example 2

[0054] A soybean protein adhesive is composed of the following raw materials in parts by mass: 28g soybean meal, 72g water, and 4g triglycidylamine.

[0055] The soy protein adhesive in this comparative example was prepared according to the following method: soybean meal and triglycidylamine were added to water according to a certain ratio, and mechanically stirred to obtain the soy protein adhesive.

[0056] Comparative Example 3

[0057] A soybean protein adhesive is prepared from the following raw materials: 28 g of soybean meal, 72 g of water, 4 g of triepoxy glycerol amine, and 0.15 g of sodium carboxymethyl cellulose.

[0058] The soybean protein adhesive of the present comparative example is prepared by the following method: according to the ratio, sodium carboxymethyl cellulose is dissolved in water to obtain a sodium carboxymethyl cellulose aqueous solution; then soybean meal and triepoxy glycerol amine are added to the sodium carboxymethyl cellulose aqueous solution, and mechanically stirred to obtain a soybean protein adhesive.

[0059] Test Example

[0060] 1. Three-layer plywood is prepared using the soybean protein adhesives prepared in Examples 1-6 and Comparative Examples 1-3 of the present application.

[0061] The size of the veneer is 200 mm x 100 mm x 2 mm.

[0062] The following normal preparation process is followed:

[0063] Gluing: single-sided gluing, with a glue application amount of 180-200 g / m 2 .

[0064] Hot pressing: pressure 1 MPa, temperature 120°C, time 6 min.

[0065] After hot pressing, the prepared plywood is placed at room temperature for 24 h, and then cut into samples of 100 mm x 25 mm x 2 mm using a cutting machine. The performance of the product is detected according to the detection method of GB / T 17657-2013 "Physicochemical Properties of Wood-based Panels and Veneered Wood-based Panels". The detection results are shown in Table 1.

[0066] Table 1: Bonding properties of soybean protein adhesives

[0067] Test piece Wet shear strength / MPa Example 1 0.92 Example 2 0.90 Example 3 0.98 Example 4 0.95 Example 5 1.07 Example 6 1.02 Comparative Example 1 0.47 Comparative Example 2 0.80 Comparative Example 3 0.85

[0068] As can be seen from Table 1, the wet shear strength of the adhesives prepared in Examples 1-6 is greater than 0.7 MPa, meeting the strength requirements of national Class II plywood. According to the results of the comparative examples, the wet shear strength of the pure soybean meal adhesive is only 0.47 MPa. The crosslinking agent forms covalent crosslinking by ring-opening reaction with soybean meal, improving the water resistance of the adhesive. The addition of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride further improves the wet shear strength of the adhesive. This is due to the electrostatic adsorption effect, as well as the unique guanidine group structure of lauroyl arginine ethyl ester hydrochloride, which forms salt bridge hydrogen bond structures with soybean meal and sodium carboxymethyl cellulose, respectively, further improving the crosslinking density and energy dissipation of the system, thereby improving the water resistance of the adhesive.

[0069] The wet shear strength of the sustainable water-resistant and mildew-resistant soybean protein adhesive prepared in Example 5 reached 1.07 MPa, which was significantly higher than that of Comparative Examples 1 to 3.

[0070] 2. Anticorrosion experiment: The soy protein adhesives prepared in Example 5 of the present invention and Comparative Example 1 were placed in a constant temperature and humidity environment, and the corruption of the adhesives was observed and recorded within 0 to 8 days. The results are as follows: Figure 1 shown.

[0071] Depend on Figure 1 As can be seen, the pure soybean meal adhesive in Comparative Example 1, due to its rich nutrients, is highly susceptible to mold attack and deteriorated after only one day. However, the adhesive containing lauroyl arginine ethyl ester hydrochloride in Example 5 remained intact after being placed in a constant temperature and humidity environment for a week. This demonstrates that the soy protein adhesive prepared in this invention has a good and long-lasting antiseptic effect.

[0072] 3. Antibacterial experiment: The soy protein adhesives prepared in Example 5 of the present invention and Comparative Example 1 were co-cultured with Staphylococcus aureus and Escherichia coli in a culture dish containing LB solid medium. At the same time, a culture medium containing Staphylococcus aureus / Escherichia coli without adding soy protein adhesive was used as a blank control. After one day, the antibacterial effect of the soy protein adhesive on Staphylococcus aureus and Escherichia coli was calculated by plate colony counting method. The results are as follows: Figure 2 shown.

[0073] Depend on Figure 2 It can be seen that the pure soybean meal adhesive in Comparative Example 1 promotes bacterial proliferation due to the rich nutrients such as protein and polysaccharides in soybean meal, covering the entire culture dish. However, the adhesive containing lauroyl arginine ethyl ester hydrochloride in Example 5 showed excellent antibacterial properties against Staphylococcus aureus and Escherichia coli, and no bacterial growth was observed in the culture dish. This is because lauroyl arginine ethyl ester hydrochloride, as a cationic surfactant, can strongly interact with the negatively charged microbial cell surface, induce potential disorder and structural changes in microorganisms, change the permeability of the cell membrane, and have a significant inhibitory effect on microorganisms such as bacteria, yeast, and mold, thereby playing an antibacterial role without the need to add additional antibacterial agents.

[0074] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A sustainable water-resistant mold-resistant soy protein adhesive, characterized in that, The method is composed of the following raw materials in parts by mass: 15-35 parts of soybean meal, 55-75 parts of water, 2-6 parts of a cross-linking agent, 0.1-0.5 parts of sodium carboxymethyl cellulose, and 0.5-2 parts of ethyl lauroyl arginine hydrochloride; The cross-linking agent is triglycidylamine or ethylene glycol diglycidyl ether.

2. The sustainable water-resistant mold-resistant soy protein adhesive of claim 1, wherein, The soybean meal has a soybean protein content of 45-50% and a fineness of 75-85 meshes.

3. The sustainable water-resistant mold-resistant soy protein adhesive of claim 1, wherein, The mass of the cross-linking agent is 2-6% of the sum of the mass of soybean meal and water.

4. The sustainable water-resistant and mildew-resistant soybean protein adhesive according to claim 1, characterized in that: The mass of the sodium carboxymethyl cellulose is 0.1-0.2% of the sum of the mass of soybean meal and water.

5. The sustainable water-resistant mold-resistant soy protein adhesive of claim 1, wherein, The mass of the lauroyl arginine ethyl ester hydrochloride is 0.5-2% of the sum of the mass of soybean meal and water.

6. The sustainable water-resistant mold-resistant soy protein adhesive of claim 1, wherein, The sustainable water-resistant and mildew-proof soy protein adhesive is composed of the following raw materials in parts by mass: 28 parts of soybean meal, 72 parts of water, 4 parts of a cross-linking agent, 0.15 parts of sodium carboxymethyl cellulose, and 1 part of lauroyl arginine ethyl ester hydrochloride; The mass of the cross-linking agent is 4% of the sum of the mass of soybean meal and water, the mass of the lauroyl arginine ethyl ester hydrochloride is 1% of the sum of the mass of soybean meal and water, and the mass of the sodium carboxymethyl cellulose is 0.15% of the sum of the mass of soybean meal and water.

7. The method of making a sustainable water-resistant mold-resistant soy protein adhesive of claim 1, characterized in that, The steps are as follows: (1) Dissolve sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride in water according to the ratio, stir and mix them to obtain a composite solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride; (2) Adding soybean meal and a cross-linking agent into the composite solution of sodium carboxymethyl cellulose and lauroyl arginine ethyl ester hydrochloride obtained in step (1) according to the ratio, mechanically stirring the mixture to obtain a sustainable water-resistant and mildew-resistant soybean protein adhesive.

8. Use of the sustainable water-resistant mold-resistant soy protein adhesive of claim 1, characterized in that, It is used in wood processing and artificial boards.

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