A mildew-proof soybean-based board adhesive

Abstract

The invention discloses a mildew-proof soybean-based sheet adhesive, wherein the raw materials include, by weight: 100 parts of soybean protein, 8-10 parts of a composite cross-linking agent, 0.2-0.4 parts of a mildew-proof agent, 2-3 parts of a surfactant, 0.04-0.05 parts of polyacrylamide, and 400-500 parts of water; wherein the composite cross-linking agent is a modified epoxy resin and tetraglycidyl methylene dianiline. The invention has good mildew-proof performance, water resistance and bonding strength.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a mildew-proof soybean-based board adhesive. Background Art

[0002] Aldehyde adhesives are often used as adhesives for composite boards, but they are prone to releasing formaldehyde during the use of boards. As people's environmental awareness increases, the market for aldehyde adhesives in boards is gradually shrinking. Soybean-based adhesives are biomass adhesives that do not release formaldehyde and can be used as board adhesives. However, since soybean-based adhesives are prone to mildew and have low waterproof properties, the boards prepared with them have low mildew resistance and water resistance, which limits the use of soybean-based adhesives. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a mildew-proof soybean-based board adhesive, which has good mildew-proof performance, water resistance and bonding strength.

[0004] The invention provides a mildew-proof soybean-based board adhesive, whose raw materials include, by weight: 100 parts of soybean protein, 8-10 parts of composite cross-linking agent, 0.2-0.4 parts of mildew-proof agent, 2-3 parts of surfactant, 0.04-0.05 parts of polyacrylamide, and 400-500 parts of water; wherein the composite cross-linking agent is modified epoxy resin and tetraglycidyl methylene dianiline.

[0005] Preferably, in the preparation process of the modified epoxy resin, ethylene glycol diglycidyl ether and hydroxyethyl hexahydro-s-triazine react under the action of a catalyst to obtain the modified epoxy resin.

[0006] Preferably, in the preparation process of the modified epoxy resin, the reaction temperature is 70-80° C. and the reaction time is 2-2.5 h.

[0007] Preferably, in the preparation process of the modified epoxy resin, the molar ratio of ethylene glycol diglycidyl ether to hydroxyethyl hexahydro-s-triazine is 1:0.1-0.2.

[0008] Preferably, in the preparation process of the modified epoxy resin, the weight ratio of the aqueous epoxy resin solution to the catalyst is 1:0.01-0.03.

[0009] Preferably, in the preparation process of the modified epoxy resin, the catalyst is triethylenediamine.

[0010] Preferably, in the preparation process of the modified epoxy resin, the reaction solvent is water.

[0011] Preferably, the weight ratio of the modified epoxy resin to tetraglycidyl methylene dianiline is 2:2-3.

[0012] Preferably, the surfactant is sodium dodecyl sulfate and gamma-glycidyloxypropyltrimethoxysilane.

[0013] Preferably, the weight ratio of sodium dodecyl sulfate to γ-glycidyloxypropyltrimethoxysilane is 3-5:1.

[0014] Preferably, the mildewcide is zinc borate.

[0015] The water mentioned above is deionized water.

[0016] The preparation method of the invention comprises the following steps: mixing polyacrylamide and water, then adding soybean protein and a surfactant, and then adding a composite cross-linking agent and a mildew preventive.

[0017] Beneficial effects:

[0018] The invention allows ethylene glycol diglycidyl ether and hydroxyethyl hexahydro-s-triazine to react under the action of a catalyst, so that the epoxy group in the ethylene glycol diglycidyl ether reacts with the hydroxyl group of the hydroxyethyl hexahydro-s-triazine to obtain a modified epoxy resin, introduces a triazine group into the epoxy resin, and then cooperates with tetraglycidyl methylene dianiline in a suitable ratio to cross-link soybean protein, thereby greatly improving the mildew resistance of the invention, and the rigidity of the triazine group can improve the strength of the invention; in addition, during the hot pressing process of the plate, the remaining epoxy groups of the modified epoxy resin and the tetraglycidyl methylene dianiline The epoxy groups in aniline can react with the active groups in soybean protein and wood to improve the bonding strength and waterproof performance of the invention; sodium dodecyl sulfate, γ-glycidyloxypropyltrimethoxysilane and polyacrylamide cooperate with each other to reduce the apparent viscosity of soybean protein, improve the fluidity and wettability of the invention, thereby further improving the bonding strength, and γ-glycidyloxypropyltrimethoxysilane can further improve the water resistance of the invention; zinc borate and hydroxyethyl hexahydro-s-triazine in the modified epoxy resin cooperate with each other to further improve the mildew resistance of the invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described in detail below through specific embodiments.

[0020] Example 1

[0021] A mildew-proof soybean-based board adhesive, the raw materials of which include, by weight: 10g soybean protein, 0.8g composite cross-linking agent, 0.04g zinc borate, 0.2g surfactant, 0.005g polyacrylamide, and 40g water; wherein the composite cross-linking agent is a mixture of modified epoxy resin and tetraglycidyl methylene dianiline in a weight ratio of 2:3;

[0022] In the preparation process of the modified epoxy resin, 1.74 g (i.e. 0.01 mol) of ethylene glycol diglycidyl ether and 0.017 g of triethylenediamine were mixed, and then 40 ml of an aqueous solution containing 0.439 g (i.e. 0.002 mol) of hydroxyethyl hexahydro-s-triazine was added, the temperature was raised to 70° C. and stirred for reaction for 2.5 h, and the modified epoxy resin was obtained by decompression and dehydration to a solid content of 20 wt %;

[0023] The surfactant is a mixture of sodium dodecyl sulfate and γ-glycidyloxypropyltrimethoxysilane in a weight ratio of 3:1.

[0024] Example 2

[0025] A mildew-proof soybean-based board adhesive, the raw materials of which include, by weight: 10g soybean protein, 1g composite cross-linking agent, 0.02g zinc borate, 0.3g surfactant, 0.004g polyacrylamide, and 50g water; wherein the composite cross-linking agent is a mixture of modified epoxy resin and tetraglycidyl methylene dianiline in a weight ratio of 1:1;

[0026] In the preparation process of the modified epoxy resin, 1.74 g (i.e. 0.01 mol) of ethylene glycol diglycidyl ether and 0.052 g of triethylenediamine were mixed, and then 20 ml of an aqueous solution containing 0.219 g (i.e. 0.001 mol) of hydroxyethyl hexahydro-s-triazine was added, the temperature was raised to 80° C. and stirred for reaction for 2 h, and dehydrated under reduced pressure to a solid content of 20 wt % to obtain the modified epoxy resin;

[0027] The surfactant is a mixture of sodium dodecyl sulfate and γ-glycidyloxypropyltrimethoxysilane in a weight ratio of 5:1.

[0028] Example 3

[0029] A mildew-proof soybean-based board adhesive, the raw materials of which include, by weight: 10g soybean protein, 0.9g composite cross-linking agent, 0.03g zinc borate, 0.25g surfactant, 0.0045g polyacrylamide, and 45g water; wherein the composite cross-linking agent is a mixture of modified epoxy resin and tetraglycidyl methylene dianiline in a weight ratio of 2:2.5;

[0030] In the preparation process of the modified epoxy resin, 1.74 g (i.e. 0.01 mol) of ethylene glycol diglycidyl ether and 0.03 g of triethylenediamine were mixed, and then 30 ml of an aqueous solution containing 0.329 g (i.e. 0.0015 mol) of hydroxyethyl hexahydro-s-triazine was added, the temperature was raised to 75° C. and stirred for reaction for 2.5 h, and dehydrated under reduced pressure to a solid content of 20 wt % to obtain the modified epoxy resin;

[0031] The surfactant is a mixture of sodium dodecyl sulfate and γ-glycidyloxypropyltrimethoxysilane in a weight ratio of 4:1.

[0032] Comparative Example 1

[0033] The composite cross-linking agent is tetraglycidyl methylene dianiline, and the other steps are the same as those in Example 3.

[0034] Comparative Example 2

[0035] The composite cross-linking agent is a modified epoxy resin, and the rest is the same as in Example 3.

[0036] Comparative Example 3

[0037] The invention does not contain γ-glycidyloxypropyltrimethoxysilane, and the other parts are the same as those in Example 3.

[0038] experiment

[0039] a. Test the bonding strength: Take 6 poplar veneers, apply the above 6 groups of adhesives on the two sides of the veneers to obtain glued veneers (with the same amount of glue), then place uncoated poplar veneers on both sides of the glued veneers perpendicular to the wood grain, and then press them into three-layer plywood under the conditions of 120℃, 1.0Mpa, and 0.55min / mm, and place them at room temperature for 3 days to obtain 6 groups of plywood. Cut the 6 groups of plywood into 20 small pieces of the same size as parallel samples, place the plywood in 60-66℃ water, soak for 3h, and then cool at room temperature for 10min, and then test the bonding strength of each group of plywood according to the method of GB / T9846-2015, and take the average bonding strength of 20 parallel samples. The results are shown in Table 1.

[0040] Table 1 Test results

[0041] Test items Bonding strength MPa Example 1 1.26 Example 2 1.18 Example 3 1.22 Comparative Example 1 0.85 Comparative Example 2 0.80 Comparative Example 3 1.05

[0042] It can be seen from Table 1 that the present invention has good water resistance and bonding strength through the cooperation of various substances.

[0043] b. Detection of the time of mildew occurrence: Prepare each group of plywood according to the method in a, and cut each group of plywood into 6 sample plates of the same size. Referring to the provisions of GB / T18261-2013, first wrap each group of sample plates with multiple layers of gauze, sterilize them in a 121℃ high-temperature sterilizer for 30 minutes, and take them out to cool to room temperature. Then, on the clean workbench, put two 3cm long glass cups that have been sterilized in advance on the culture dish that has been full of mycelium, arrange them in parallel, and then put the sterilized 2 sample plates of each group on the glass rod. Make 3 parallel samples for each group of samples, and finally culture them in a constant temperature and humidity box at 25-28℃ and relative humidity of 85% for 4 weeks, observe them regularly, and the surface infection values ​​of mold and discoloration bacteria on the sample plates are graded as shown in Table 2, and the experimental results are shown in Table 3.

[0044] Table 2 Infection value classification

[0045] Infection value Sample infection area 0 There is no mycelium or mildew on the surface of the sample 1 The infected area of ​​the sample surface is less than 1 / 4 2 The infected area of ​​the sample surface is 1 / 4 to 1 / 2 3 The infected area of ​​the sample surface is 1 / 2 to 3 / 4 4 The infected area of ​​the sample surface is > 3 / 4

[0046] Table 3 Experimental results

[0047] Test items Infection value Example 1 1 Example 2 1 Example 3 1 Comparative Example 1 3 Comparative Example 2 1 Comparative Example 3 1

[0048] It can be seen from Table 3 that the present invention has good mildew resistance.

[0049] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A mildew-proof soybean-based board adhesive, characterized in that: The raw materials include, by weight: 100 parts of soybean protein, 8-10 parts of composite cross-linking agent, 0.2-0.4 parts of mildew inhibitor, 2-3 parts of surfactant, 0.04-0.05 parts of polyacrylamide, and 400-500 parts of water; wherein the composite cross-linking agent is modified epoxy resin and tetraglycidyl methylene dianiline; In the preparation process of the modified epoxy resin, ethylene glycol diglycidyl ether reacts with hydroxyethyl hexahydro-s-triazine under the action of a catalyst to obtain the modified epoxy resin; In the preparation process of modified epoxy resin, the reaction temperature is 70-80°C and the reaction time is 2-2.5h; In the preparation process of the modified epoxy resin, the molar ratio of ethylene glycol diglycidyl ether to hydroxyethyl hexahydro-s-triazine is 1:0.1-0.2; In the preparation of modified epoxy resin, the catalyst is triethylenediamine; In the preparation process of the modified epoxy resin, the reaction solvent is water; The weight ratio of the modified epoxy resin to tetraglycidyl methylene diphenylamine is 2:2-3; The surfactants are sodium dodecyl sulfate and γ-glycidyloxypropyltrimethoxysilane; The weight ratio of sodium dodecyl sulfate to γ-glycidyloxypropyltrimethoxysilane is 3-5:

1.

2. The mildew-proof soybean-based board adhesive according to claim 1, characterized in that: In the preparation process of the modified epoxy resin, the weight ratio of ethylene glycol diglycidyl ether to the catalyst is 1:0.01-0.

03.

3. The mildew-proof soybean-based board adhesive according to claim 1 or 2, characterized in that: The mildew inhibitor is zinc borate.