A self-crosslinking acrylic emulsion type composite adhesive and a preparation method thereof

Abstract

This invention discloses a self-crosslinking acrylic emulsion composite adhesive, belonging to the field of composite adhesive technology. It comprises a tackifying resin, soft monomers, hard monomers, hydroxyethyl acrylate, acrylic acid, crosslinking monomers, emulsifiers, initiators, wetting agents, defoamers, thickeners, preservatives, and deionized water. This invention utilizes the crosslinking polymerization reaction of soft and hard monomers, functional monomers, and crosslinking monomers to obtain the soft core portion of a core-shell acrylic emulsion. After obtaining the soft core portion of the core-shell acrylic emulsion, the tackifying resin, soft monomers, functional monomers, and crosslinking monomers are polymerized onto the soft core portion, thereby obtaining a unique soft-core, hard-shell self-crosslinking acrylic emulsion. When the soft-core, hard-shell self-crosslinking acrylic emulsion obtained by this invention is used in composite adhesives, there is no need to mix the tackifying emulsion, tackifying resin, and curing agent.

Description

Technical Field

[0001] This invention relates to the field of composite adhesive technology, and in particular to a self-crosslinking acrylic emulsion composite adhesive and its preparation method. Background Technology

[0002] Existing composite adhesives for indoor flooring and wall decoration typically fail to simultaneously meet the requirements of high bonding strength, temperature resistance, plasticizer resistance, and environmental friendliness. They are mainly solvent-based, and solvent-based composite adhesives are usually obtained through polymerization reactions in organic solvents, or by mixing tackifying emulsions, tackifying resins, and curing agents into polymer emulsions. In actual production and application, this can lead to serious safety, hygiene, and environmental problems, posing a significant threat to human health. At the same time, the use of tackifying emulsions can introduce excessive emulsifiers into the composite adhesive, reducing its performance. Meanwhile, the use of curing agents can cause problems with poor storage stability and excessively high crosslinking and unsealing temperatures.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a self-crosslinking acrylic emulsion composite adhesive and its preparation method, aiming to solve the problem that existing composite adhesive products cannot simultaneously meet the requirements of high bonding strength, temperature resistance, plasticizer resistance, environmental protection, low crosslinking unblocking temperature, and good storage stability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A self-crosslinking acrylic emulsion composite adhesive comprises the following components in parts by weight:

[0007] The ingredients are: 120-150 parts tackifying resin, 380-410 parts soft monomer, 65-100 parts hard monomer, 8.5-13.5 parts hydroxyethyl acrylate, 4.5-6.5 parts acrylic acid, 13-21 parts crosslinking monomer, 8-15 parts emulsifier, 2.75-3 parts initiator, 1-2 parts wetting agent, 1-1.5 parts defoamer, 0-2 parts thickener, 1-2 parts preservative, and 300-350 parts deionized water.

[0008] The tackifying resin used is either TSR-6000×50 or TSR-0065×50.

[0009] The soft monomer includes one or both of butyl acrylate and isooctyl acrylate;

[0010] The hard monomer includes one or more of methyl methacrylate, styrene, and acrylonitrile.

[0011] In the self-crosslinking acrylic emulsion composite adhesive, the crosslinking monomer includes one or more of N-hydroxymethylacrylamide, diacetone acrylamide, and adipate dihydrazide.

[0012] In the self-crosslinking acrylic emulsion composite adhesive, the emulsifier includes anionic emulsifiers and nonionic emulsifiers; the anionic emulsifier includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl diphenyl ether disulfonate; the nonionic emulsifier includes one or both of dodecyl polyoxyethylene ether and tridecyl polyoxyethylene ether.

[0013] In the self-crosslinking acrylic emulsion composite adhesive, the ratio of the anionic emulsifier to the nonionic emulsifier by weight is (2-5):5.

[0014] In the self-crosslinking acrylic emulsion composite adhesive, the initiator includes one or more of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0015] In the self-crosslinking acrylic emulsion composite adhesive, the wetting agent includes one or both of sodium diisooctyl succinate sulfonate and sodium diisooctyl succinate sulfonate.

[0016] In the self-crosslinking acrylic emulsion composite adhesive, the thickener includes one or both of polyurethane associative thickeners and acrylate thickeners.

[0017] In the self-crosslinking acrylic emulsion composite adhesive, the preservative is Kathon.

[0018] This invention also provides a method for preparing the aforementioned self-crosslinking acrylic emulsion composite adhesive, wherein the self-crosslinking acrylic emulsion composite adhesive is the aforementioned self-crosslinking acrylic emulsion composite adhesive, specifically including the following steps:

[0019] Step S001. Preparation of monomer emulsion A: Add 280-350 parts of soft monomer, 65-100 parts of hard monomer, 7-11 parts of hydroxyethyl acrylate, 3.5-5 parts of acrylic acid, and 7-16 parts of crosslinking monomer to the emulsification tank. After stirring and mixing evenly, add 100-120 parts of deionized water and 6-12 parts of emulsifier to the emulsification tank. Stir and mix evenly to obtain monomer emulsion A.

[0020] Step S002. Preparation of core layer polymer emulsion: Under nitrogen protection, add 5% by weight of monomer emulsion A to a polymerization reactor containing 180-200 parts of deionized water. After the temperature inside the polymerization reactor is raised to 78℃-80℃, add 0.8 parts of initiator. Then raise the temperature inside the polymerization reactor to 84℃-85℃ and continue to add 1-1.2 parts of initiator and the remaining monomer emulsion A. Finally, keep warm for 30 minutes to obtain the core layer polymer emulsion.

[0021] Step S003. Preparation of monomer emulsion B: First, add 2-3 parts of emulsifier and 20-30 parts of deionized water to the emulsification tank, stir and disperse, then add 60-100 parts of soft monomer, 1.5-2.5 parts of hydroxyethyl acrylate, 1-1.5 parts of acrylic acid, 2-5 parts of crosslinking monomer and 120-150 parts of tackifying resin to the emulsification tank, stir and mix evenly to obtain monomer emulsion B;

[0022] Step S004. Preparation of core-shell polymer emulsion: Add monomer emulsion B and 0.75 to 1.2 parts of initiator dropwise to the core polymer emulsion, and keep warm for 1 hour after the addition is completed to obtain core-shell polymer emulsion;

[0023] Step S005. After the core-shell polymer emulsion is obtained, the temperature of the polymerization reactor is lowered to 40℃~42℃, and the pH of the core-shell polymer emulsion is adjusted to 7.9~8.2 with ammonia water. After pH adjustment, 0~4 parts of crosslinking monomer, 1~2 parts of wetting agent, 1~1.5 parts of defoamer, 0~2 parts of thickener and 1~2 parts of preservative are added, and then the mixture is passed through a 200-mesh sieve to obtain the self-crosslinking acrylic emulsion composite adhesive.

[0024] Beneficial effects:

[0025] This invention provides an acrylic emulsion-type composite adhesive and its preparation method. The method utilizes a crosslinking polymerization reaction of soft and hard monomers, functional monomers, and crosslinking monomers to obtain the soft core portion of a core-shell acrylic emulsion. After obtaining the soft core portion of the core-shell acrylic emulsion, tackifying resin, soft monomers, functional monomers, and crosslinking monomers are polymerized onto the soft core portion, resulting in a unique soft-core, hard-shell self-crosslinking acrylic emulsion. Because the acrylic emulsion can undergo a self-crosslinking reaction during drying, there is no need to mix a curing agent into the emulsion, thus improving the storage stability of the emulsion and composite adhesive products and avoiding the problem of excessively high crosslinking unsealing temperatures. Furthermore, since the tackifying resin is polymerized into the acrylic emulsion, there is no need to introduce aqueous tackifying emulsions or dissolved tackifying resins in organic solvents when formulating the composite adhesive. This avoids harm to the environment and human health, and because aqueous tackifying emulsions are not used, the adhesive strength, temperature resistance, and plasticizer resistance of the composite adhesive do not decrease due to excessive emulsifier content.

[0026] The soft-core, hard-shell self-crosslinking acrylic emulsion obtained by this invention exhibits excellent bonding strength to both polar and non-polar substrates. It can be used directly to bond substrates or formulated into composite adhesives by adding fillers. While ensuring that the composite adhesive simultaneously meets the requirements of high bonding strength, temperature resistance, plasticizer resistance, environmental friendliness, low crosslinking unblocking temperature, and good storage stability, the good initial tack of the soft-core, hard-shell self-crosslinking acrylic emulsion and its strong wettability on the substrate after film formation further enhance the bonding strength of the composite adhesive to the substrate. Detailed Implementation

[0027] This invention provides a self-crosslinking acrylic emulsion composite adhesive and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following embodiments are provided to further illustrate the invention in detail. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0028] A self-crosslinking acrylic emulsion composite adhesive comprises the following components in parts by weight:

[0029] The ingredients are: 120-150 parts tackifying resin, 380-410 parts soft monomer, 65-100 parts hard monomer, 8.5-13.5 parts hydroxyethyl acrylate, 4.5-6.5 parts acrylic acid, 13-21 parts crosslinking monomer, 8-15 parts emulsifier, 2.75-3 parts initiator, 1-2 parts wetting agent, 1-1.5 parts defoamer, 0-2 parts thickener, 1-2 parts preservative, and 300-350 parts deionized water.

[0030] The tackifying resin used is either TSR-6000×50 or TSR-0065×50.

[0031] The soft monomer includes one or both of butyl acrylate and isooctyl acrylate;

[0032] The hard monomer includes one or more of methyl methacrylate, styrene, and acrylonitrile.

[0033] In the above composition, the soft monomer and hard monomer are the main monomers, and hydroxyethyl acrylate and acrylic acid are the functional monomers. By causing the main monomers, functional monomers, and crosslinking monomers to undergo a crosslinking polymerization reaction, the core portion of a core-shell acrylic emulsion can be obtained. Then, a tackifying resin is grafted onto the core portion of the core-shell acrylic emulsion, thereby obtaining a core-shell acrylic emulsion polymerized with the tackifying resin. Since the acrylic emulsion can self-cure and form a film after drying, there is no need to mix a curing agent into the emulsion, which improves the storage stability of the emulsion and the composite adhesive product, and avoids the problem of excessively high crosslinking unsealing temperature. In addition, since the tackifying resin is polymerized into the acrylic emulsion, there is no need to introduce water-based tackifying emulsions and organic solvents to dissolve the tackifying resin when formulating the composite adhesive. This does not cause harm to the environment and human health. Furthermore, since water-based tackifying emulsions (which contain a lot of emulsifiers) are not used, the bonding strength, temperature resistance, plasticizer resistance, and other properties of the composite adhesive will not decrease due to the presence of too much emulsifier in the composite adhesive.

[0034] Furthermore, among the soft monomers, butyl acrylate is more polar than isooctyl acrylate, so the type of soft monomer to be added to the composite adhesive can be selected according to the different substrates to which the composite adhesive is bonded.

[0035] Furthermore, among the hard monomers, acrylonitrile is more polar than methyl methacrylate and styrene, so the type of hard monomer to be added to the composite adhesive can be selected according to the different substrates to which the composite adhesive is bonded.

[0036] Furthermore, the acrylic acid can provide hydrogen bonds to the acrylic emulsion, thereby improving the bonding strength of the composite adhesive to the substrate; while hydroxyethyl acrylate can provide carboxyl groups to the acrylic emulsion. Thus, when using the composite adhesive, the carboxyl groups can also form hydrogen bonds between the substrate and the composite adhesive, thereby further improving the bonding strength of the composite adhesive to the substrate.

[0037] Furthermore, the tackifying resin is manufactured by Guangxi Tongxuan Lixin Chemical Co., Ltd., and uses either TSR-6000×50 or TSR-0065×50 tackifying resin. Both of these tackifying resins are reactive tackifying resins, which are more easily grafted onto the core portion of the core-shell acrylic emulsion during use, thereby significantly improving the bonding strength of the composite adhesive product. Specifically, TSR-6000×50 tackifying resin has excellent bonding effect on polar substrates, while TSR-0065×50 tackifying resin has good bonding effect on non-polar substrates. Therefore, the specific type of tackifying resin can be selected according to the different substrates to which the composite adhesive is bonded.

[0038] In addition, the aforementioned tackifying resin itself has a high glass transition temperature and can be used as a hard monomer.

[0039] Furthermore, the crosslinking monomer includes one or more of N-hydroxymethylacrylamide, diacetone acrylamide, and adipate dihydrazide. These crosslinking monomers can participate in the polymerization reaction, and when the acrylic emulsion dries to form a film, the polymer chains can self-crosslink under the action of the crosslinking groups to produce a polymer with a network structure, thereby improving the bonding strength of the composite adhesive to the substrate.

[0040] Furthermore, the activity of the aforementioned crosslinking monomers is lower than that of dedicated curing agents. Therefore, the introduction of crosslinking monomers into acrylic emulsions will not cause a decrease in the storage stability of the emulsions and composite adhesive products.

[0041] Furthermore, the emulsifier includes anionic and nonionic emulsifiers; the anionic emulsifier includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl diphenyl ether disulfonate; the nonionic emulsifier includes one or both of dodecyl polyoxyethylene ether and tridecyl polyoxyethylene ether. The aforementioned anionic emulsifiers have strong emulsifying ability, react quickly during monomer polymerization, and have high conversion efficiency; while the addition of the aforementioned nonionic emulsifiers to the emulsion can improve the chemical stability, mechanical stability, and freeze resistance of the emulsion and the composite adhesive.

[0042] Furthermore, the ratio of the anionic emulsifier to the nonionic emulsifier by weight is (2-5):5.

[0043] Furthermore, the initiator includes one or more of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0044] Furthermore, the wetting agent includes one or both of sodium diisooctyl succinate sulfonate and sodium diisooctyl succinate sulfonate.

[0045] Furthermore, the thickener includes one or both of polyurethane associative thickeners and acrylate thickeners.

[0046] Furthermore, the preservative is Kathon.

[0047] This invention also provides a method for preparing the aforementioned self-crosslinking acrylic emulsion composite adhesive, wherein the self-crosslinking acrylic emulsion composite adhesive is the aforementioned self-crosslinking acrylic emulsion composite adhesive, specifically including the following steps:

[0048] Step S001. Preparation of monomer emulsion A: Add 280-350 parts of soft monomer, 65-100 parts of hard monomer, 7-11 parts of hydroxyethyl acrylate, 3.5-5 parts of acrylic acid, and 7-16 parts of crosslinking monomer to the emulsification tank. After stirring and mixing evenly, add 100-120 parts of deionized water and 6-12 parts of emulsifier to the emulsification tank. Stir and mix evenly to obtain monomer emulsion A.

[0049] Step S002. Preparation of core layer polymer emulsion: Under nitrogen protection, add 5% by weight of monomer emulsion A to a polymerization reactor containing 180-200 parts of deionized water. After the temperature inside the polymerization reactor is raised to 78℃-80℃, add 0.8 parts of initiator. Then raise the temperature inside the polymerization reactor to 84℃-85℃ and continue to add 1-1.2 parts of initiator and the remaining monomer emulsion A. Finally, keep warm for 30 minutes to obtain the core layer polymer emulsion.

[0050] Step S003. Preparation of monomer emulsion B: First, add 2-3 parts of emulsifier and 20-30 parts of deionized water to the emulsification tank, stir and disperse, then add 60-100 parts of soft monomer, 1.5-2.5 parts of hydroxyethyl acrylate, 1-1.5 parts of acrylic acid, 2-5 parts of crosslinking monomer and 120-150 parts of tackifying resin to the emulsification tank, stir and mix evenly to obtain monomer emulsion B;

[0051] Step S004. Preparation of core-shell polymer emulsion: Add monomer emulsion B and 0.75 to 1.2 parts of initiator dropwise to the core polymer emulsion, and keep warm for 1 hour after the addition is completed to obtain core-shell polymer emulsion;

[0052] Step S005. After the core-shell polymer emulsion is obtained, the temperature of the polymerization reactor is lowered to 40℃~42℃, and the pH of the core-shell polymer emulsion is adjusted to 7.9~8.2 with ammonia water. After pH adjustment, 0~4 parts of crosslinking monomer, 1~2 parts of wetting agent, 1~1.5 parts of defoamer, 0~2 parts of thickener and 1~2 parts of preservative are added, and then the mixture is passed through a 200-mesh sieve to obtain the self-crosslinking acrylic emulsion composite adhesive.

[0053] In preparing a self-crosslinking acrylic emulsion composite adhesive, this invention first utilizes a crosslinking polymerization reaction of soft monomers, hard monomers, functional monomers, and crosslinking monomers to obtain the soft core portion of a core-shell acrylic emulsion. After obtaining the soft core portion, tackifying resins, soft monomers, functional monomers, and crosslinking monomers are polymerized onto the soft core portion, thereby obtaining a unique soft-core, hard-shell self-crosslinking acrylic emulsion. The soft-core, hard-shell self-crosslinking acrylic emulsion obtained by this invention exhibits high bonding strength to both polar and non-polar substrates. It can be used directly for bonding substrates or formulated into a composite adhesive by adding fillers. While simultaneously meeting requirements such as high bonding strength, temperature resistance, plasticizer resistance, environmental friendliness, low crosslinking unblocking temperature, and good storage stability, the good initial tack of the soft-core, hard-shell self-crosslinking acrylic emulsion and its strong wettability on the substrate after film formation further enhance the bonding strength of the composite adhesive to the substrate.

[0054] To further illustrate the self-crosslinking acrylic emulsion composite adhesive and its preparation method provided by the present invention, the following examples are provided:

[0055] Example 1

[0056] A self-crosslinking acrylic emulsion composite adhesive comprises the following components in parts by weight:

[0057] 120 parts of TSR-0065×50 tackifying resin, 300 parts of butyl acrylate, 110 parts of isooctyl acrylate, 40 parts of methyl methacrylate, 60 parts of styrene, 13.5 parts of hydroxyethyl acrylate, 6.5 parts of acrylic acid, 21 parts of N-hydroxymethylacrylamide, 3.2 parts of sodium dodecylbenzene sulfonate, 4.8 parts of dodecyl polyoxyethylene ether, 2.75 parts of ammonium persulfate, 2 parts of sodium diisooctyl succinate sulfonate, 1 part of defoamer, 2 parts of acrylate thickener, 1 part of Kathon, and 300 parts of deionized water.

[0058] This invention also provides a method for preparing the self-crosslinking acrylic emulsion composite adhesive, specifically comprising the following steps:

[0059] Step S001. Preparation of monomer emulsion A: Add 240 parts of butyl acrylate, 110 parts of isooctyl acrylate, 40 parts of methyl methacrylate, 60 parts of styrene, 11 parts of hydroxyethyl acrylate, 5 parts of acrylic acid and 16 parts of N-hydroxymethylacrylamide to the emulsification tank, stir and mix evenly, then add 100 parts of deionized water, 2.4 parts of sodium dodecylbenzenesulfonate and 3.6 parts of dodecyl polyoxyethylene ether to the emulsification tank, stir and mix evenly to obtain monomer emulsion A;

[0060] Step S002. Preparation of core layer polymer emulsion: Under nitrogen protection, 5% by weight of monomer emulsion A is added to a polymerization reactor containing 100 parts of deionized water. After the temperature inside the polymerization reactor is raised to 78°C, 0.8 parts of ammonium persulfate are added. Then the temperature inside the polymerization reactor is raised to 85°C, and 1.2 parts of ammonium persulfate and the remaining monomer emulsion A are added dropwise. Finally, the temperature is maintained for 30 minutes to obtain the core layer polymer emulsion.

[0061] Step S003. Preparation of monomer emulsion B: First, add 0.8 parts of sodium dodecylbenzenesulfonate, 1.2 parts of dodecyl polyoxyethylene ether and 20 parts of deionized water to the emulsification tank. After stirring and dispersing, add 60 parts of butyl acrylate, 2.5 parts of hydroxyethyl acrylate, 1.5 parts of acrylic acid, 5 parts of N-hydroxymethylacrylamide and 120 parts of TSR-0065×50 type tackifying resin to the emulsification tank. After stirring and mixing evenly, monomer emulsion B is obtained.

[0062] Step S004. Preparation of core-shell polymer emulsion: Add monomer emulsion B and 0.75 parts of ammonium persulfate dropwise to the core polymer emulsion, and keep warm for 1 hour after the addition is completed to obtain core-shell polymer emulsion;

[0063] Step S005. After obtaining the core-shell polymer emulsion, lower the temperature of the polymerization reactor to 40°C and adjust the pH of the core-shell polymer emulsion to 8 with ammonia. After pH adjustment, add 2 parts of sodium diisooctyl succinate sulfonate, 1 part of defoamer, 2 parts of acrylate thickener, and 1 part of Kathon. Then, pass the emulsion through a 200-mesh sieve to obtain a solid content of 60%, a viscosity of 2000-3000 mPa·s (3#, 30 rpm), and a pH of approximately 8.0.

[0064] Self-crosslinking acrylic emulsion composite adhesive.

[0065] Example 2

[0066] A self-crosslinking acrylic emulsion composite adhesive comprises the following components in parts by weight:

[0067] 150 parts of TSR-6000×50 tackifying resin, 380 parts of butyl acrylate, 40 parts of methyl methacrylate, 25 parts of acrylonitrile, 7.0 parts of hydroxyethyl acrylate, 3.5 parts of acrylic acid, 7 parts of diacetone acrylamide, 4 parts of adipate dihydrazide, 7.5 parts of sodium dodecyl diphenyl ether disulfonate, 7.5 parts of ammonium persulfate, 1 part of sodium diisooctyl succinate sulfonate, 1.5 parts of defoamer, 2 parts of Kathon, and 350 parts of deionized water.

[0068] This invention also provides a method for preparing the self-crosslinking acrylic emulsion composite adhesive, specifically comprising the following steps:

[0069] Step S001. Preparation of monomer emulsion A: Add 280 parts of butyl acrylate, 40 parts of methyl methacrylate, 25 parts of acrylonitrile, 7 parts of hydroxyethyl acrylate, 3.5 parts of acrylic acid and 9 parts of acetone acrylamide to the emulsification tank, stir and mix evenly, then add 120 parts of deionized water, 6 parts of sodium dodecyl diphenyl ether disulfonate and 6 parts of tridecyl polyoxyethylene ether to the emulsification tank, stir and mix evenly to obtain monomer emulsion A;

[0070] Step S002. Preparation of core layer polymer emulsion: Under nitrogen protection, 5% by weight of monomer emulsion A is added to a polymerization reactor containing 200 parts of deionized water. After the temperature inside the polymerization reactor is raised to 78°C, 0.8 parts of ammonium persulfate are added. Then the temperature inside the polymerization reactor is raised to 85°C, and 1 part of ammonium persulfate and the remaining monomer emulsion A are added dropwise. Finally, the temperature is maintained for 30 minutes to obtain the core layer polymer emulsion.

[0071] Step S003. Preparation of monomer emulsion B: First, add 1.5 parts of sodium dodecyl diphenyl ether disulfonate, 1.5 parts of tridecyl polyoxyethylene ether and 30 parts of deionized water to the emulsification tank. After stirring and dispersing, add 100 parts of butyl acrylate, 1.5 parts of hydroxyethyl acrylate, 1 part of acrylic acid, 2 parts of acetone acrylamide and 150 parts of TSR-6000×50 type tackifying resin to the emulsification tank. Stir and mix evenly to obtain monomer emulsion B.

[0072] Step S004. Preparation of core-shell polymer emulsion: Add monomer emulsion B and 1.2 parts of ammonium persulfate dropwise to the core polymer emulsion, and keep warm for 1 hour after the addition is completed to obtain core-shell polymer emulsion;

[0073] Step S005. After the core-shell polymer emulsion is obtained, the temperature of the polymerization reactor is lowered to 40°C, and the pH of the core-shell polymer emulsion is adjusted to 8 with ammonia. After pH adjustment, 1 part of sodium diisooctyl succinate sulfonate, 1.5 parts of defoamer, 2 parts of Kathon, and 4 parts of adipic acid dihydrazide are added. Then, the emulsion is passed through a 200-mesh sieve to obtain a self-crosslinking acrylic emulsion composite adhesive with a solid content of 54%, a viscosity of <500 mPa·s (2#, 60 rpm), and a pH of around 8.0.

[0074] Performance Test 1:

[0075] The self-crosslinking acrylic emulsion prepared in Example 1 was applied to a PVC (polyvinyl chloride) board using a doctor blade (wet adhesive 40g / m²). 3 After natural drying for 8 hours, XPE (crosslinked polyvinyl chloride) foam material was laminated (2Kg pressure rolling). After curing for another day, the 90° peel strength and shear tensile strength of the XPE foam material were tested (test standard: JC / T550-2008). The test results are shown in Table 1 below. At the same time, the surface drying time of the wet adhesive and the storage stability of the emulsion / composite adhesive after 30 days of heat storage at 50℃ were recorded.

[0076] Performance Test 2:

[0077] The self-crosslinking acrylic emulsion prepared in Example 1 was applied to a PVC board using a scraper (wet adhesive 40g / m²). 3 After natural drying for 8 hours, NBR (nitrile butadiene rubber) foam material was laminated (2Kg pressure rolling). The 90° peel strength and shear tensile strength of the NBR foam material were then tested. The test results are shown in Table 1 below. The surface drying time of the wet adhesive and the storage stability of the emulsion / composite adhesive after 30 days of heat storage at 50°C were also recorded.

[0078] Performance Test 3:

[0079] A composite adhesive was prepared by mixing commercially available Basf378 emulsion and rosin glycerol ester (the amount of rosin glycerol ester was 10% of the mass of Basf378 emulsion, and 20% organic solvent was added to the rosin glycerol ester). After preparation, the composite adhesive was applied to a PVC board using a scraper (wet adhesive 40g / m²). 3 After natural drying for 8 hours, XPE foam material was laminated (2Kg pressure rolling). The 90° peel strength and shear tensile strength of the XPE foam material were then tested. The test results are shown in Table 1 below. The surface drying time of the wet adhesive and the storage stability of the composite adhesive after 30 days of heat storage at 50°C were also recorded.

[0080] Performance Test 4:

[0081] A composite adhesive is prepared by mixing commercially available Basf378 emulsion, rosin glycerol ester (10% of the mass of Basf378 emulsion, containing 20% ​​organic solvent), and a sealing and curing agent (1% of the mass of Basf378 emulsion). After preparation, the composite adhesive is applied to a PVC board using a scraper (wet adhesive 40g / m²). 3 After natural drying for 8 hours, XPE foam material was laminated (2Kg pressure rolling). The 90° peel strength and shear tensile strength of the XPE foam material were then tested. The test results are shown in Table 1 below. The surface drying time of the wet adhesive and the storage stability of the composite adhesive after 30 days of heat storage at 50°C were also recorded.

[0082] Table 1:

[0083]

[0084] The test results in Table 1 show that, due to the high solid content of the self-crosslinking acrylic emulsion prepared in Example 1, the surface drying time of the wet adhesive is short, and it is close to that of composite adhesives formulated with Basf378 emulsion and tackifying resin widely used in the market. Furthermore, the self-crosslinking acrylic emulsion prepared in Example 1 can be directly used to bond foamed materials, and without the use of organic solvents, it achieves a peel strength superior to that of composite adhesives formulated with Basf378 emulsion and tackifying resin widely used in the market, while its shear strength is close to that of such composite adhesives. Therefore, it exhibits good bonding strength to both polar and non-polar substrates.

[0085] Performance Test 5:

[0086] The self-crosslinking acrylic emulsion obtained in Example 2 was mixed with light calcium powder at a weight ratio of 1:1. A thickener was then added to adjust the viscosity of the mixture to 10,000-20,000 mPa·s to obtain the composite adhesive. The composite adhesive was then applied to a cement board using a scraper (wet adhesive 200-300 g / m²). 3 After drying at room temperature for 1 hour, PVC rolls were laminated (2Kg pressure rolling). After curing for 1 day and 7 days, the 90° peel strength and shear tensile strength of the PVC rolls were tested. The test results are shown in Table 2 below. The surface drying time of the wet adhesive and the stability of the composite adhesive after 30 days of heat storage at 50℃ were also recorded.

[0087] Performance Test 6:

[0088] The self-crosslinking acrylic emulsion prepared in Example 2 was mixed with a mixture of light calcium powder and aluminum hydroxide (wherein the weight ratio of light calcium powder to aluminum hydroxide was 1:2) at a ratio of 1:1 by weight. A thickener was then added to adjust the viscosity of the mixture to 10,000-20,000 mPa·s to obtain the composite adhesive. The composite adhesive was then applied to a cement board using a scraper (wet adhesive 200-300 g / m²). 3 After drying at room temperature for 1 hour, PVC rolls were laminated (2Kg pressure rolling). After curing for 1 day and 7 days, the 90° peel strength and shear tensile strength of the PVC rolls were tested. The test results are shown in Table 2 below. The surface drying time of the wet adhesive and the storage stability of the composite adhesive after 30 days of heat storage at 50℃ were also recorded.

[0089] Performance Test 7:

[0090] Apply Henkel K188E floor adhesive (commercially available) to the cement board using a scraper (wet adhesive 200~300g / m²). 3 After drying at room temperature for 1 hour, PVC rolls were laminated (2Kg pressure rolling). After curing for 1 day and 7 days, the 90° peel strength and shear tensile strength of the PVC rolls were tested. The test results are shown in Table 2 below. The surface drying time of the wet adhesive and the storage stability of the adhesive after 30 days of heat storage at 50°C were also recorded.

[0091] Table 2:

[0092]

[0093] As can be seen from the test results in Table 2, the self-crosslinking acrylic emulsion prepared in Example 2 can be used in combination with fillers to formulate composite adhesives. Compared with commercially available products, the composite adhesives have better shear resistance and anti-plasticization properties, higher bonding strength to the substrate, and no gelation or precipitation occurs during storage even with a higher powder-to-liquid ratio. In the composite adhesive of performance test 6, aluminum hydroxide powder was used to replace part of the light calcium powder. Although the bonding strength of the composite adhesive was slightly reduced, its flame retardancy and smoke suppression properties greatly contribute to the safety of decoration.

[0094] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A self-crosslinking acrylic emulsion-based hybrid adhesive, characterized by, Composed of the following components by weight: The ingredients are: 120-150 parts tackifying resin, 380-410 parts soft monomer, 65-100 parts hard monomer, 8.5-13.5 parts hydroxyethyl acrylate, 4.5-6.5 parts acrylic acid, 13-21 parts crosslinking monomer, 8-15 parts emulsifier, 2.75-3 parts initiator, 1-2 parts wetting agent, 1-1.5 parts defoamer, 0-2 parts thickener, 1-2 parts preservative, and 300-350 parts deionized water. The tackifying resin used is either TSR-6000×50 or TSR-0065×50; both tackifying resins are reactive tackifying resins and are used as hard monomers. The soft monomer includes one or both of butyl acrylate and isooctyl acrylate; The hard monomer includes one or more of methyl methacrylate, styrene, and acrylonitrile; The crosslinking monomer includes one or more of N-hydroxymethylacrylamide, diacetone acrylamide, and adipate dihydrazide; The preparation method of the self-crosslinking acrylic emulsion composite adhesive includes the following steps: Step S001. Preparation of monomer emulsion A: Add 350 parts of soft monomer, 65-100 parts of hard monomer, 7-11 parts of hydroxyethyl acrylate, 3.5-5 parts of acrylic acid, and 16 parts of crosslinking monomer to the emulsification tank. After stirring and mixing evenly, add 100-120 parts of deionized water and 6-12 parts of emulsifier to the emulsification tank. After stirring and mixing evenly, monomer emulsion A is obtained. Step S002. Preparation of core layer polymer emulsion: Under nitrogen protection, add 5% by weight of monomer emulsion A to a polymerization reactor containing 180-200 parts of deionized water. After the temperature inside the polymerization reactor is raised to 78℃-80℃, add 0.8 parts of initiator. Then raise the temperature inside the polymerization reactor to 84℃-85℃ and continue to add 1.2 parts of initiator and the remaining monomer emulsion A. Finally, keep warm for 30 minutes to obtain the core layer polymer emulsion. Step S003. Preparation of monomer emulsion B: First, add 2-3 parts of emulsifier and 20-30 parts of deionized water to the emulsification tank, stir and disperse, then add 60 parts of soft monomer, 1.5-2.5 parts of hydroxyethyl acrylate, 1-1.5 parts of acrylic acid, 2-5 parts of crosslinking monomer and 120-150 parts of tackifying resin to the emulsification tank, stir and mix evenly to obtain monomer emulsion B; Step S004. Preparation of core-shell polymer emulsion: Add monomer emulsion B and 0.75 parts of initiator dropwise to the core polymer emulsion. After the addition is completed, keep warm for 1 hour to obtain core-shell polymer emulsion, so that the tackifying resin is polymerized into the polymer emulsion. Step S005. After the core-shell polymer emulsion is obtained, the temperature of the polymerization reactor is lowered to 40℃~42℃, and the pH of the core-shell polymer emulsion is adjusted to 7.9~8.2 with ammonia water. After pH adjustment, 1~2 parts of wetting agent, 1~1.5 parts of defoamer, 0~2 parts of thickener and 1~2 parts of preservative are added, and then the emulsion is passed through a 200-mesh sieve to obtain the self-crosslinking acrylic emulsion composite adhesive.

2. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 1, characterized by, The emulsifier includes anionic emulsifiers and nonionic emulsifiers; the anionic emulsifier includes one or both of sodium dodecylbenzenesulfonate and sodium dodecyl diphenyl ether disulfonate; the nonionic emulsifier includes one or both of dodecyl polyoxyethylene ether and tridecyl polyoxyethylene ether.

3. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 2, characterized by, The ratio of the anionic emulsifier to the nonionic emulsifier by weight is (2-5):

5.

4. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 1, characterized by, The initiator includes one or more of ammonium persulfate, potassium persulfate, and sodium persulfate.

5. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 1, characterized by, The wetting agent includes one or both of sodium diisooctyl succinate sulfonate and sodium diisooctyl succinate sulfonate.

6. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 1, characterized by, The thickener includes one or both of polyurethane associative thickeners and acrylate thickeners.

7. The self-crosslinking acrylic emulsion-based composite adhesive according to claim 1, characterized by, The preservative is Kathon.

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