Two-component water-based splicing adhesive and preparation method thereof

Abstract

The application discloses a two-component water-based splicing adhesive, and raw materials for preparing the A component include the following in parts by weight: emulsion 40-55 parts, filler 4-6 parts, chain extender 3-5 parts, functional monomer 1-3 parts, auxiliary 1-3 parts, defoaming agent 0.1-1 part, and dispersing agent 0.1-0.5 part. The functional monomer combination of vinyl versatate and methyl methacrylate can improve the mechanical properties of the EVA emulsion splicing adhesive system and has good weather resistance. Toluene diisocyanate and trimethylolpropane are used as the B component, so that the failed splicing adhesive no longer has the brushing performance, the miscoating event of the adhesive applicator after the splicing adhesive fails is greatly avoided, and the easy-to-open adhesive problem after the splicing adhesive fails is eliminated from the source.

Description

Technical Field

[0001] This invention relates to a two-component water-based plywood adhesive and its preparation method, specifically to the field of adhesives (C09J). Background Technology

[0002] As living standards improve, people's demands for wooden furniture are gradually increasing. Using adhesive to bond spliced ​​wood panels can achieve a better appearance. Compared to mortise and tenon joints, the processing technology requirements are lower, and compared to metal nails, the appearance is more aesthetically pleasing. However, adhesive needs to be mixed and used immediately. After prolonged periods of disuse, the two-component adhesive will become ineffective. However, workers applying the adhesive may not be aware of this ineffectiveness and may still retain its application properties. Misuse of this adhesive can easily lead to the spliced ​​wood panels coming apart, especially in dry or humid environments, affecting the performance of the spliced ​​wood panels and wasting time.

[0003] Chinese invention patent CN202011183823.4 discloses a water-based single-component adhesive for bamboo and its preparation method. It improves the bonding strength between the adhesive and bamboo by crosslinking a mixed emulsion of acrylate and vinyl acetate with propane trimethylol triacrylate. However, bamboo has a lower moisture content than ordinary softwood or hardwood, and the adhesive is prone to water absorption and failure in woods with high moisture content. Chinese invention patent CN201610545593.9 discloses a water-based two-component adhesive emulsion and its preparation method. It improves the crack resistance of the adhesive emulsion by introducing flexible chains into the latex particles; however, the resulting adhesive has poor mechanical properties and is prone to creep cracking in high-temperature environments. Summary of the Invention

[0004] To monitor the process quality of the plywood adhesive and prevent the adhesive from being misused by workers after it has expired, the first aspect of this invention provides a two-component water-based plywood adhesive. Component A, by weight, comprises: 40-55 parts emulsion, 4-6 parts filler, 3-5 parts chain extender, 1-3 parts functional monomer, 1-3 parts additives, 0.1-1 parts defoamer, and 0.1-0.5 parts dispersant.

[0005] In a preferred embodiment, the emulsion is selected from one or a combination of several of acrylic emulsions, EVA emulsions, styrene-butadiene emulsions, styrene-acrylic emulsions, and polyurethane emulsions.

[0006] In a preferred embodiment, the viscosity of the EVA emulsion is 3800-10000 mPa·s.

[0007] In a preferred embodiment, the filler is selected from one or a combination of several of talc, barium sulfate, silica, attapulgite clay, and silica.

[0008] In a preferred embodiment, the filler is fumed silica, preferably with a specific surface area of ​​370-430 m². 2 / g.

[0009] In a preferred embodiment, the additive is silane coupling agent KH-550.

[0010] In a preferred embodiment, the chain extender is selected from one or a combination of several of dihydroxy alcohols, polyhydroxy alcohols, acid anhydrides, and epoxides.

[0011] In a preferred embodiment, the chain extender is diethylaminoethanol.

[0012] The applicant discovered that ester bonds in EVA emulsions are prone to hydrolysis when the moisture content is high, leading to a decrease in molecular weight and an increase in the number of terminal carboxyl groups, resulting in a decline in the mechanical properties of the plywood adhesive. When diethylaminoethanol is introduced, it can react with the ester bonds in the EVA system, linking small molecule polymers and forming a bridging effect, reducing the hydrolysis of ester bonds, thereby improving the water resistance and weather resistance of the plywood adhesive.

[0013] In a preferred embodiment, the defoamer is a silicone polyether defoamer. The dispersant is a nonionic surfactant, preferably a polyoxyethylene-polyoxypropylene block polyether.

[0014] In a preferred embodiment, the functional monomer is selected from one or a combination of several of acrylic acid, acrylic acid derivatives, and ethylene ester derivatives.

[0015] In a preferred embodiment, the acrylic derivative is selected from one or a combination of several of butyl acrylate, isobutyl acrylate, methyl methacrylate, methacrylic acid, hydroxyethyl acrylate, and hydroxypropyl acrylate.

[0016] In a preferred embodiment, the ethylene ester derivative is selected from one or a combination of several of ethylene carbonate, vinyl acetate, and polyvinyl acetate.

[0017] In a preferred embodiment, the functional monomer is a combination of methyl methacrylate and ethylene carbonate. More preferably, the ethylene carbonate is ethylene tert-carbonate.

[0018] In a preferred embodiment, the weight ratio of ethylene tert-carbonate to methyl methacrylate is (3-8):3; more preferably, the weight ratio of ethylene tert-carbonate to methyl methacrylate is (4-7):3; and even more preferably, the weight ratio of ethylene tert-carbonate to methyl methacrylate is 5:3.

[0019] The applicant discovered that, due to the small contact area between the splicing board and the splicing adhesive, a high adhesive force is required between the splicing adhesive and the splicing board to achieve a good bonding effect. The applicant found that introducing a combination of ethylene tert-carbonate and methyl methacrylate into the EVA emulsion system, with a weight ratio of ethylene tert-carbonate to methyl methacrylate of (4-7):3, can improve the adhesion between the splicing adhesive and the splicing board, and it is not easy to delaminate in dry and humid environments, exhibiting good weather resistance. The possible reasons are as follows: Ethylene tert-carbonate can participate in the polymerization reaction in the system, improving the cohesiveness of the adhesive. Furthermore, ethylene tert-carbonate has good hydrophobicity, and its flexible groups can improve the regularity of the film formation, filling dislocations during film formation and making the film denser. Additionally, the large steric hindrance of ethylene tert-carbonate can prevent the ester groups from being attacked by hydrolytic attacks from hydroxyl groups, hydrogen groups, and water, improving the weather resistance of the adhesive. At the same time, the synergistic effect of ethylene tert-carbonate and methyl methacrylate can improve the mechanical properties of the adhesive, bringing better mechanical properties to the adhesive. However, excessive use of methyl methacrylate can lead to an increase in the hardness of the adhesive, making it prone to deformation in high and low temperature environments, affecting the performance of the adhesive.

[0020] In a preferred embodiment, the water-based plywood adhesive also requires the addition of component B, which is a curing agent, and the weight ratio of component A to component B is 100:(20-30).

[0021] In a preferred embodiment, the weight ratio of component A to component B is 100:(21-25).

[0022] In a preferred embodiment, the weight ratio of component A to component B is 100:23.

[0023] In a preferred embodiment, the curing agent is selected from one or a combination of several of aliphatic amine curing agents, aromatic curing agents, amide amine curing agents, and isocyanate curing agents.

[0024] In a preferred embodiment, the isocyanate curing agent is selected from one or a combination of several of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate.

[0025] In a preferred embodiment, the isocyanate curing agent is toluene diisocyanate.

[0026] In a preferred embodiment, component B is a combination of toluene diisocyanate and trimethylolpropane.

[0027] In a preferred embodiment, the weight ratio of toluene diisocyanate to trimethylolpropane is (3-5):1.

[0028] In a preferred embodiment, the weight ratio of toluene diisocyanate to trimethylolpropane is 3:1.

[0029] During the experiment, the applicant discovered that when using a two-component panel adhesive, foaming occurs after component A and component B are mixed. Component B reacts and dissolves, but the adhesive still retains its brushing properties. If workers unknowingly use this adhesive, the coated panels are prone to delamination, especially in humid or dry environments, leading to a reduced lifespan for the panels. The applicant found that by using toluene diisocyanate and trimethylolpropane synergistically as component B, when mixed with component A (EVA emulsion), the active groups on the toluene diisocyanate are consumed. After a period of time, the mixed panel adhesive clumps together and loses its brushing properties, greatly preventing accidental application by workers after the adhesive has deteriorated, thus eliminating the problem of easy delamination after adhesive failure at its source.

[0030] A second aspect of the present invention provides a method for preparing a two-component water-based plywood adhesive, comprising the following steps:

[0031] (1) Add the emulsion by weight under stirring;

[0032] (2) Then add filler, chain extender, functional monomer, additive, defoamer and dispersant according to the weight parts, and react under stirring. Filter to obtain mixture.

[0033] (3) When using, add component B to the filtered mixture, stir well, and repeatedly scoop up the colloid with a stirrer 3-5 times until evenly coated. Then brush it onto the board and apply 500-1500 kg / m². 2 Press for 30-120 minutes, then cure at room temperature.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The two-component water-based plywood adhesive of the present invention, by using a combination of functional monomers of ethylene tert-carbonate and methyl methacrylate, can improve the mechanical properties of the EVA emulsion plywood adhesive system and have good weather resistance.

[0036] (2) The two-component water-based panel adhesive of the present invention uses toluene diisocyanate and trimethylolpropane as component B, which can make the panel adhesive no longer have brushing properties after failure, greatly avoiding the accidental application of the panel adhesive by the adhesive applicator after failure, and eliminating the problem of easy delamination after failure of panel adhesive from the source.

[0037] (3) The two-component water-based splicing adhesive of the present invention can improve the water resistance and weather resistance of the EVA emulsion system splicing adhesive by introducing diethylaminoethanol chain extender, extend the service life of the splicing adhesive, and is not easy to crack in dry or humid environments.

[0038] (4) The two-component water-based plywood adhesive of the present invention, by introducing a coupling agent and a specific surface area of ​​370-430 m², is used to achieve the desired effect. 2 / g of fumed silica can increase the adhesion of plywood glue, thus improving both the internal strength of the glue and its surface adhesion to the wood.

[0039] (5) The two-component water-based plywood adhesive of the present invention uses EVA emulsion as the base system, which can make the plywood adhesive have good flexibility, so that it has good bonding effect with both hardwood and softwood, and the water-based system has no environmental protection pressure. Detailed Implementation

[0040] Example 1

[0041] A two-component water-based plywood adhesive, wherein component A comprises, by weight, 55 parts emulsion, 5 parts filler, 4 parts chain extender, 2 parts functional monomer, 2 parts additives, 0.3 parts defoamer, and 0.3 parts dispersant.

[0042] The emulsion is an EVA emulsion with a viscosity of 8000 mPa·s, purchased from Jinan Jinxuyuan New Material Co., Ltd., model number 707.

[0043] The filler is fumed silica with a specific surface area of ​​400 m². 2 / g, purchased from Wacker Chemie in Germany, model HDK T40.

[0044] The auxiliary agent is silane coupling agent KH-550, purchased from Chenguang Chemical. The chain extender is diethylaminoethanol.

[0045] The defoamer is a silicone polyether defoamer, purchased from Shanghai Ziyi Chemical Co., Ltd., model ZY-7581; the dispersant is a polyoxyethylene-polyoxypropylene block polyether, purchased from Jining Tangyi Chemical Co., Ltd.

[0046] The functional monomer is a combination of ethylene tert-carbonate and methyl methacrylate in a weight ratio of 5:3.

[0047] Component B is a combination of toluene diisocyanate and trimethylolpropane in a weight ratio of 3:1.

[0048] The weight ratio of component A to component B is 100:23.

[0049] A method for preparing a two-component water-based plywood adhesive includes the following steps:

[0050] (1) Add the emulsion by weight under stirring;

[0051] (2) Then add filler, chain extender, functional monomer, additive, defoamer and dispersant according to the weight parts, and react under stirring. Filter to obtain mixture.

[0052] (3) When using, add component B to the filtered mixture, stir well, and repeatedly scoop up the colloid 5 times with a stirrer until it is evenly coated. Then brush it onto the board and apply 1500 kg / m². 2 Press for 120 minutes, then cure at 30°C.

[0053] The board material is mahogany board.

[0054] Example 2

[0055] A two-component water-based plywood adhesive, with the same steps as in Example 1, except that the weight ratio of component A to component B is 100:18.

[0056] The adhesive board is made of pine wood.

[0057] Example 3

[0058] A two-component water-based plywood adhesive, with the same steps as in Example 1, except that the functional monomer is a combination of ethylene carbonate and methyl methacrylate.

[0059] Example 4

[0060] A two-component water-based plywood adhesive, with the same steps as in Example 1, except that component B is toluene diisocyanate.

[0061] Performance testing

[0062] 1. Weather resistance: After bonding the two-component water-based plywood adhesive prepared in Examples 1-4 to the plywood, the plywood was boiled in boiling water. The test was conducted to determine how long it would take for the adhesive to come unglued.

[0063] 2. Peel strength: The peel strength of the two-component water-based plywood adhesive prepared according to GB / T 1457-2005 standard after bonding with the plywood.

[0064] 3. Brushing performance after placement: After the two-component water-based plywood adhesive prepared in Examples 1-4 was placed in the environment for 24 hours, it was picked up with a brush to test whether it could still be brushed.

[0065] The test results are shown in Table 1.

[0066] Table 1

[0067] Boiling time / h Peel strength (N.mm / mm) Brushing performance Example 1 456 142 Clumps cannot be brushed Example 2 453 145 Clumps cannot be brushed Example 3 432 125 Clumps cannot be brushed Example 4 410 119 Can be brushed

Claims

1. A two-component waterborne panel adhesive, characterized by, The raw materials include A component and B component, the A component includes emulsion 40-55 parts, filler 4-6 parts, chain extender 3-5 parts, functional monomer 1-3 parts, auxiliary 1-3 parts, defoaming agent 0.1-1 parts, dispersing agent 0.1-0.5 parts by weight; The emulsion is EVA emulsion, the viscosity of the EVA emulsion is 3800-10000 mPa.s; The chain extender is diethylamino ethanol; The functional monomer is the combination of tertiary carbonic acid vinyl ester and methyl methacrylate, the weight ratio is (3-8):3; The B component is curing agent, the B component is the combination of toluene diisocyanate and trimethylolpropane, the weight ratio is (3-5):1; The adding weight ratio of the A component and B component is 100:(20-30).

2. The two-component water-based panel adhesive according to claim 1, characterized in that, The filler is selected from one or several combinations of talc, barium sulfate, silica, attapulgite clay, white carbon black.

3. A method for preparing the two-component waterborne panel adhesive according to any one of claims 1-2, characterized in that, The steps include: (1) under the action of stirring, add emulsion by weight; (2) then add filler, chain extender, functional monomer, auxiliary, defoaming agent, dispersing agent by weight, react under the action of stirring, filter to get mixture; (3) Use, in the mixture after filtration, add B component, stirring, uniform, with stirrer repeatedly 3-5 times, uniform after the plate can be brushed on, then 500-1500kg / m 2 Press 30-120min, room temperature curing after.