Rubber enhanced water-based adhesive and preparation method thereof

Abstract

The invention discloses a rubber enhanced water-based adhesive and a preparation method thereof, and relates to the technical field of water-based adhesives, the rubber enhanced water-based adhesive is composed of silane modified SBS rubber, acrylic acid soft monomers, acrylic acid hard monomers, acrylic acid functional monomers, an emulsifier, potassium persulfate and deionized water; the silane modified SBS rubber is prepared according to the following steps: dispersing SBS rubber in first allyl acrylate, stirring until the SBS rubber is dissolved, adding a silane coupling agent and benzoyl peroxide, stirring, heating and reacting to obtain the silane modified SBS rubber; according to the invention, the SBS rubber is modified by adopting the organosiloxane active monomer containing the carbon-carbon double bond, and the side chain of organosilicone is grafted to the molecular chain of the SBS rubber, so that the water resistance, solvent resistance and stain resistance of the modified rubber are improved; in addition, due to the introduction of the organosiloxane active monomer, the reaction activity of the SBS rubber is also increased, so that the SBS rubber can be more easily subjected to polymerization reaction with the selected monomer.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based adhesives, in particular to a rubber-reinforced water-based adhesive and a preparation method thereof. Background Art

[0002] Water-based adhesives greatly reduce the environmental burden because they use no or only a small amount of organic solvents in their production process. They are excellent environmentally friendly adhesives. However, water-based adhesives have low mechanical strength and poor elastic properties, which limit their use.

[0003] SBS rubber is a styrene-butadiene-styrene block copolymer with a unique two-phase microstructure. Polystyrene segments form cross-linked hard segments, imparting rigidity and processing properties to the material, while polybutadiene segments form elastic soft segments, providing excellent flexibility and resilience. In theory, this molecular structure is highly compatible with the hard and soft monomers in acrylic emulsion systems in terms of chemical composition and performance characteristics, enabling a synergistic mechanism of hard-soft phase structures, achieving complementary performance and enhanced functionality. However, SBS rubber itself has a complex phase structure, difficult cross-linking control, and poor compatibility with other materials, limiting its use in water-based adhesives.

[0004] Therefore, there is an urgent need for a water-based adhesive with strong mechanical properties and excellent elastic properties to meet the growing demand for high-performance, environmentally friendly materials in industries such as coatings, adhesives and plastics. Summary of the Invention

[0005] To solve the above problems, the object of the present invention is to provide a rubber-reinforced water-based adhesive and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0007] A rubber-reinforced water-based adhesive, comprising the following raw materials, in parts by weight: 19 to 36 parts of silane-modified SBS rubber, 10 to 20 parts of acrylic soft monomer, 8 to 15 parts of acrylic hard monomer, 5 to 13 parts of acrylic functional monomer, 1 to 3 parts of emulsifier, 0.2 to 0.8 parts of potassium persulfate, and 40 to 60 parts of deionized water;

[0008] The silane-modified SBS rubber is prepared according to the following steps:

[0009] Dispersing the SBS rubber in the first allyl acrylate, stirring until the SBS rubber is dissolved, adding a silane coupling agent and benzoyl peroxide, stirring and heating to 78-82° C. and reacting for 2.5-3.5 hours to obtain a silane-modified SBS rubber;

[0010] The mass ratio of SBS rubber, first allyl acrylate, silane coupling agent and benzoyl peroxide is 4-8:15-25:0.1-2:0.1-0.5;

[0011] The silane coupling agent is a silane coupling agent containing a carbon-carbon double bond, such as γ-(methacryloyloxy)propyltrimethoxysilane, silane coupling agent A151, silane coupling agent A171 or silane coupling agent A172.

[0012] Preferably, the silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane.

[0013] Preferably, the acrylic functional monomer is an acrylic self-crosslinking monomer, a second allyl acrylate or dimethylaminoethyl methacrylate.

[0014] Preferably, the acrylic soft monomer is one or both of 2-nonyl acrylate, 2-propylethyl acrylate or n-butyl acrylate.

[0015] Preferably, the acrylic hard monomer is one or two of benzyl methacrylate, tert-butyl 2-bromoacrylate or methyl α-chloroacrylate.

[0016] Preferably, the emulsifier is octylphenol polyoxyethylene ether or sodium lauryl sulfate.

[0017] Preferably, the model of the SBS rubber is YH-188, YH-501, YH-791, YH-792 or YH-796.

[0018] The present invention also includes a method for preparing a rubber-reinforced water-based adhesive, comprising the following steps:

[0019] ① In parts by weight, 10 to 20 parts of acrylic soft monomer, 8 to 15 parts of acrylic hard monomer, and 5 to 13 parts of acrylic functional monomer are mixed evenly to obtain a mixed monomer, which is set aside;

[0020] ② Add 40-60 parts of deionized water, 19-36 parts of silane-modified SBS rubber, and 1-3 parts of emulsifier to a reactor, stir evenly, and then heat to 78-82° C., add the mixed monomer obtained in step ① dropwise to the reactor under stirring, and simultaneously add 0.2-0.8 parts of potassium persulfate dropwise to the reactor as an initiator, control the temperature of the reactor at 78-82° C. during the addition, and react for 1-2 hours after the addition is complete to obtain a rubber-reinforced water-based adhesive.

[0021] In the preparation method of the present invention, the acrylic acid monomer is added dropwise in a starvation manner, and the dropwise addition manner can enable the conversion rate of the acrylic acid monomer to reach above 98%.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The rubber-reinforced water-based adhesive of the present invention uses an organosiloxane reactive monomer containing a carbon-carbon double bond (TMSPMA for short) to modify SBS rubber, grafting the side chains of the organosiloxane onto the molecular chain of the SBS rubber, thereby improving the water resistance, solvent resistance and stain resistance of the modified rubber. In addition, the introduction of TMSPMA also increases the reactivity of the SBS rubber, making it easier for it to undergo polymerization reactions with selected monomers.

[0024] First, SBS rubber, as a styrene-butadiene-styrene block copolymer, exhibits a unique two-phase microstructure. Polystyrene segments form cross-linked hard segments, imparting rigidity and processing properties, while polybutadiene segments form elastic soft segments, providing excellent flexibility and resilience. This molecular structure closely matches the chemical composition and performance characteristics of the hard and soft monomers in acrylic emulsion systems, forming a synergistic mechanism based on the hard-soft phase structure, which can achieve complementary performance and enhanced functionality in water-based adhesives.

[0025] Secondly, γ-(methacryloyloxy)propyltrimethoxysilane (TMSPMA) is an organosiloxane reactive monomer containing a carbon-carbon double bond, which can introduce functional groups into the polymer chain through chemical reactions. In SBS rubber modification applications, the siloxane portion of TMSPMA can hydrolyze and condense under specific conditions to form a self-crosslinking network. The carbon-carbon double bonds of the butadiene segments in the SBS rubber generate active free radicals under the action of an initiator. The silanol compounds containing carbon-carbon double bonds generated after the hydrolysis of TMSPMA also generate active free radicals under the action of an initiator. These two free radicals then undergo an addition reaction, grafting the organic portion of TMSPMA onto the SBS rubber chain, thereby improving the water resistance, solvent resistance, and stain resistance of the modified rubber.

[0026] Finally, the introduction of TMSPMA can also increase the reactivity of SBS rubber, making it easier to polymerize with selected acrylic monomers. By combining the advantages of modified SBS rubber and acrylic monomers, a new water-based adhesive with high-strength adhesion, excellent water resistance and environmentally friendly properties can be developed through polymerization reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 1 is a graph showing the particle size distribution of the rubber-reinforced water-based adhesive obtained in Example 10;

[0028] Figure 2 This is a schematic electron microscope diagram of the rubber-reinforced water-based adhesive obtained in Example 10. DETAILED DESCRIPTION

[0029] The purpose of the present invention is to provide a rubber-reinforced water-based adhesive and a preparation method thereof, which is achieved through the following technical solutions:

[0030] Acrylic acid self-crosslinking monomer is also called self-crosslinking acrylic acid monomer and is provided by Beijing Baiyuan Chemical Co., Ltd.

[0031] The schematic route of TMSPMA hydrolysis is as follows:

[0032] CH2=C(CH3)COOC3H6Si(OCH3)3+3H2O→CH2=C(CH3)COOC3H6Si(OH)3+3CH3OH

[0033] The reaction and hydrolysis routes of SBS rubber, allyl acrylate and TMSPMA are as follows:

[0034]

[0035] g represents grafting, and m and n represent the number of acrylic acid monomer and TMSPMA units grafted onto SBS, respectively.

[0036] The present invention is further described below with reference to specific embodiments.

[0037] Example 1

[0038] A rubber-reinforced water-based adhesive, comprising the following raw materials: 19 kg of silane-modified SBS rubber, 10 kg of 2-nonyl acrylate, 8 kg of benzyl methacrylate, 5 kg of acrylic acid self-crosslinking monomer, 1 kg of octylphenol polyoxyethylene ether, 0.2 kg of potassium persulfate, and 40 kg of deionized water;

[0039] The silane-modified SBS rubber is prepared according to the following steps:

[0040] 4 kg of SBS rubber was dispersed in 15 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 0.1 kg of silane coupling agent and 0.1 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 78°C for 2.5 hours to obtain silane-modified SBS rubber.

[0041] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0042] The model of the SBS rubber is YH-792.

[0043] Example 2

[0044] A rubber-reinforced water-based adhesive, comprising the following raw materials: 36 kg of silane-modified SBS rubber, 20 kg of 2-propylethyl acrylate, 15 kg of tert-butyl 2-bromoacrylate, 13 kg of allyl acrylate, 3 kg of sodium lauryl sulfate, 0.8 kg of potassium persulfate, and 60 kg of deionized water;

[0045] The silane-modified SBS rubber is prepared according to the following steps:

[0046] 8.8 kg of SBS rubber was dispersed in 27.5 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 2.2 kg of silane coupling agent and 0.55 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 82° C. for 3.5 hours to obtain silane-modified SBS rubber.

[0047] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0048] The model of the SBS rubber is YH-501.

[0049] Example 3

[0050] A rubber-reinforced water-based adhesive, comprising the following raw materials: 20 kg of silane-modified SBS rubber, 12 kg of n-butyl acrylate, 10 kg of methyl α-chloroacrylate, 6 kg of dimethylaminoethyl methacrylate, 1.5 kg of octylphenol polyoxyethylene ether, 0.3 kg of potassium persulfate, and 42 kg of deionized water;

[0051] The silane-modified SBS rubber is prepared according to the following steps:

[0052] 5 kg of SBS rubber was dispersed in 16 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 0.5 kg of silane coupling agent and 0.2 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 80°C for 3 hours to obtain silane-modified SBS rubber.

[0053] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0054] The model of the SBS rubber is YH-791.

[0055] Example 4

[0056] A rubber-reinforced water-based adhesive, comprising the following raw materials: 25 kg of silane-modified SBS rubber, 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 45 kg of deionized water;

[0057] The silane-modified SBS rubber is prepared according to the following steps:

[0058] 6 kg of SBS rubber was dispersed in 18 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 0.8 kg of silane coupling agent and 0.4 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 79 ° C for 3 hours to obtain silane-modified SBS rubber.

[0059] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0060] The model of the SBS rubber is YH-188.

[0061] Example 5

[0062] A rubber-reinforced water-based adhesive, comprising the following raw materials: 32 kg of silane-modified SBS rubber, 8 kg of 2-propylethyl acrylate, 10 kg of n-butyl acrylate, 8 kg of tert-butyl 2-bromoacrylate, 2 kg of methyl α-chloroacrylate, 12 kg of an acrylic acid self-crosslinking monomer, 2.5 kg of octylphenol polyoxyethylene ether, 0.7 kg of potassium persulfate, and 55 kg of deionized water;

[0063] The silane-modified SBS rubber is prepared according to the following steps:

[0064] 6 kg of SBS rubber was dispersed in 26.4 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 1.68 kg of silane coupling agent and 0.48 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 80° C. for 3 hours to obtain silane-modified SBS rubber.

[0065] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0066] The model of the SBS rubber is YH-796.

[0067] Example 6

[0068] A rubber-reinforced water-based adhesive is prepared from the following raw materials: 25 kg of silane-modified SBS rubber, 10 kg of 2-nonyl acrylate, 5 kg of n-butyl acrylate, 5 kg of benzyl methacrylate, 5 kg of methyl α-chloroacrylate, 10 kg of dimethylaminoethyl methacrylate, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 50 kg of deionized water.

[0069] The silane-modified SBS rubber is prepared according to the following steps:

[0070] 5 kg of SBS rubber was dispersed in 20 kg of allyl acrylate and stirred until the SBS rubber was dissolved. 1 kg of silane coupling agent and 0.4 kg of benzoyl peroxide were added, and the mixture was stirred and heated to 80°C for 3 hours to obtain silane-modified SBS rubber.

[0071] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0072] The model of the SBS rubber is YH-188.

[0073] Example 7

[0074] The method for preparing the rubber-reinforced water-based adhesive described in Example 1 comprises the following steps:

[0075] ① Evenly mix 10 kg of 2-nonyl acrylate, 8 kg of benzyl methacrylate, and 5 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0076] ② Add 40 kg of deionized water, 19 kg of silane-modified SBS rubber, and 1 kg of octylphenol polyoxyethylene ether to a reactor, stir evenly, and then heat to 78°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.2 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor to be 78°C during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is complete, react for 1 hour to obtain a rubber-reinforced water-based adhesive.

[0077] Example 8

[0078] The method for preparing a rubber-reinforced water-based adhesive described in Example 2 comprises the following steps:

[0079] ① Evenly mix 20 kg of 2-propyl ethyl acrylate, 15 kg of 2-tert-butyl bromoacrylate, and 13 kg of allyl acrylate to obtain a mixed monomer for later use;

[0080] ② Add 60 kg of deionized water, 36 kg of silane-modified SBS rubber, and 3 kg of sodium lauryl sulfate to a reactor, stir evenly, and then heat to 82°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. Simultaneously, add 0.8 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 82°C during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is complete, react for 2 hours to obtain a rubber-reinforced water-based adhesive.

[0081] Example 9

[0082] The method for preparing a rubber-reinforced water-based adhesive described in Example 3 comprises the following steps:

[0083] ① Evenly mix 12 kg of n-butyl acrylate, 10 kg of methyl α-chloroacrylate, and 6 kg of dimethylaminoethyl methacrylate to obtain a mixed monomer for later use;

[0084] ② Add 42 kg of deionized water, 20 kg of silane-modified SBS rubber, and 1.5 kg of octylphenol polyoxyethylene ether to a reactor, stir evenly, and then heat to 79° C. The mixed monomer obtained in step ① is added dropwise to the reactor under stirring. At the same time, 0.3 kg of potassium persulfate is added dropwise to the reactor as an initiator. The temperature of the reactor is controlled to be 79° C. during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is completed, the reaction is allowed to react for 1.5 hours to obtain a rubber-reinforced water-based adhesive.

[0085] Example 10

[0086] The method for preparing a rubber-reinforced water-based adhesive described in Example 4 comprises the following steps:

[0087] ① Evenly mix 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, and 8 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0088] ② Add 45 kg of deionized water, 25 kg of silane-modified SBS rubber, and 2 kg of sodium lauryl sulfate to a reactor, stir evenly, and then heat to 81°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. Simultaneously, add 0.5 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 81°C during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is complete, react for 2 hours to obtain a rubber-reinforced water-based adhesive.

[0089] Example 11

[0090] The method for preparing a rubber-reinforced water-based adhesive described in Example 5 comprises the following steps:

[0091] ① Evenly mix 8 kg of 2-propylethyl acrylate, 10 kg of n-butyl acrylate, 8 kg of tert-butyl 2-bromoacrylate, 2 kg of methyl α-chloroacrylate and 12 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0092] ② Add 55 kg of deionized water, 32 kg of silane-modified SBS rubber, and 2.5 kg of octylphenol polyoxyethylene ether to the reactor, stir evenly, and then heat to 80°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.7 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 80°C during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is complete, react for 1.5 hours to obtain a rubber-reinforced water-based adhesive.

[0093] Example 12

[0094] The method for preparing a rubber-reinforced water-based adhesive described in Example 6 comprises the following steps:

[0095] ① Evenly mix 10 kg of 2-nonyl acrylate, 5 kg of n-butyl acrylate, 5 kg of benzyl methacrylate, 5 kg of methyl α-chloroacrylate, and 10 kg of dimethylaminoethyl methacrylate to obtain a mixed monomer, which is set aside;

[0096] ② Add 50 kg of deionized water, 25 kg of silane-modified SBS rubber, and 2 kg of sodium lauryl sulfate to a reactor, stir evenly, and then heat to 80°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. Simultaneously, add 0.5 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 80°C during the addition (the addition time can generally be controlled within 2.5 to 3.5 hours). After the addition is complete, react for 1.5 hours to obtain a rubber-reinforced water-based adhesive.

[0097] The rubber-reinforced water-based adhesives obtained in Examples 7 to 12 were subjected to performance testing, and the results are shown in Table 1. The pH test was conducted using a pH meter, and the viscosity test was conducted using an NDJ-8S digital viscometer. The test temperature was 23±2°C. The tensile strength and elongation at break tests were conducted in accordance with the relevant requirements of GB / T1040-2018, and the water absorption test was conducted in accordance with the relevant requirements of GB / T1733-1993. Conversion rate = actual measured solids content / theoretical calculated solids content * 100%.

[0098] Table 1 Performance index table of rubber-reinforced water-based adhesives obtained in Examples 7 to 12

[0099]

[0100]

[0101] As can be seen from the results in Table 1, the rubber-reinforced water-based adhesive obtained by the present invention can achieve a tensile strength of 16 MPa or more, even exceeding 22 MPa, and an elongation at break of 695% or more, even exceeding 785%. The high tensile strength indicates that the SBS rubber modified with the silane coupling agent indeed plays a reinforcing role in the water-based adhesive, which also means that the adhesive is less likely to be damaged when subjected to tension, ensuring the strong bond. During the modification of the SBS rubber, the siloxane portion of TMSPMA can hydrolyze and condense into a self-crosslinking network. The carbon-carbon double bonds of the butadiene segments in the SBS rubber generate active free radicals under the action of an initiator. The silanol compound containing a carbon-carbon double bond generated after the hydrolysis of TMSPMA also generates active free radicals under the action of an initiator. The two free radicals undergo an addition reaction, causing the organic portion of TMSPMA to be grafted onto the molecular chain of the SBS rubber, increasing its reactivity and making it easier to undergo polymerization with other acrylic monomers, forming a compact network structure, thereby exhibiting excellent mechanical properties.

[0102] The rubber-reinforced water-based adhesive obtained by the present invention has low water absorption, indicating excellent water resistance and structural stability. Specifically, the low water absorption reflects the adhesive's high crosslink density, which effectively blocks water permeation pathways, thereby ensuring stable bond strength and stability even in humid environments. It also indicates that the adhesive possesses a certain degree of density after film formation.

[0103] Comparative Example 1

[0104] A water-based adhesive is prepared from the following raw materials: 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 27 kg of deionized water;

[0105] The preparation method of the above-mentioned water-based adhesive comprises the following steps:

[0106] ① Evenly mix 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, and 8 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0107] ② Add 27 kg of deionized water and 2 kg of sodium lauryl sulfate to the reactor, stir evenly and then heat to 81 ° C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.5 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 81 ° C during the addition (the addition time is controlled to about 3 hours). After the addition is completed, react for 2 hours to obtain a water-based adhesive.

[0108] Comparative Example 2

[0109] A water-based adhesive is prepared from the following raw materials: 0.8 kg of γ-(methacryloyloxy)propyltrimethoxysilane, 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 27 kg of deionized water;

[0110] The preparation method of the above-mentioned water-based adhesive comprises the following steps:

[0111] ① Evenly mix 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, and 8 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0112] ② Add 27 kg of deionized water, 0.8 kg of γ-(methacryloyloxy)propyltrimethoxysilane and 2 kg of sodium lauryl sulfate to the reactor, stir evenly and then heat to 81 ° C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.5 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor to be 81 ° C during the addition (the addition time is controlled to be about 3 hours). After the addition is completed, react for 2 hours to obtain a water-based adhesive.

[0113] Comparative Example 3

[0114] A water-based adhesive is prepared from the following raw materials: 6 kg of SBS YH-188 rubber, 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 31 kg of deionized water;

[0115] The preparation method of the above-mentioned water-based adhesive comprises the following steps:

[0116] ① Evenly mix 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, and 8 kg of acrylic acid self-crosslinking monomer to obtain a mixed monomer, which is set aside;

[0117] ② Add 31 kg of deionized water, 6 kg of SBS YH-188 rubber, and 2 kg of sodium lauryl sulfate to the reactor, stir evenly, and then heat to 81°C. Add the mixed monomer obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.5 kg of potassium persulfate dropwise to the reactor as an initiator. Control the temperature of the reactor at 81°C during the addition (the addition time is controlled to be about 3 hours). After the addition is completed, react for 2 hours to obtain a water-based adhesive.

[0118] Comparative Example 4

[0119] A water-based adhesive is prepared from the following raw materials: 6 kg of SBS YH-188 rubber, 18 kg of allyl acrylate, 0.8 kg of γ-(methacryloyloxy)propyltrimethoxysilane, 0.4 kg of benzoyl peroxide, 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer, 2 kg of sodium lauryl sulfate, 0.5 kg of potassium persulfate, and 45 kg of deionized water;

[0120] The preparation method of the above-mentioned water-based adhesive comprises the following steps:

[0121] ① 18 kg of allyl acrylate, 7 kg of 2-nonyl acrylate, 8 kg of 2-propylethyl acrylate, 2 kg of benzyl methacrylate, 10 kg of tert-butyl 2-bromoacrylate, 8 kg of acrylic acid self-crosslinking monomer and 0.8 kg of γ-(methacryloyloxy)propyltrimethoxysilane were mixed to obtain a mixed monomer for later use;

[0122] ② Add 45kg of deionized water, 6kg of SBS YH-188 rubber and 2kg of sodium lauryl sulfate to the reactor, stir evenly and then heat to 81°C. Add the mixed monomers obtained in step ① dropwise to the reactor under stirring. At the same time, add 0.4kg of benzoyl peroxide and 0.5kg of potassium sulfate dropwise to the reactor as initiators. Control the temperature of the reactor to be 81°C during the addition (the addition time is controlled to be about 3 hours). After the addition is completed, react for 2 hours to obtain a water-based adhesive.

[0123] The performance tests were conducted on the water-based adhesives obtained in Comparative Examples 1 to 4. The viscosity test of Tu-4 was conducted in accordance with the relevant requirements of GB / T1723-1993. The other test methods were the same as those in Table 1. The test results are shown in Table 2.

[0124] Table 2 Performance results of water-based adhesives obtained in Comparative Examples 1 to 4

[0125]

[0126] The results in Table 2 show that SBS rubber that has not been modified with a silane coupling agent cannot directly react with acrylic monomers. Therefore, in Comparative Examples 3 and 4, SBS rubber and acrylic emulsions are incompatible, resulting in failure of the water-based adhesive indicators. In addition, since no modified SBS rubber is added in Comparative Examples 1 and 2, the water-based adhesives have low tensile strength and low viscosity.

[0127] The particle size distribution and electron scanning microscopy analysis of the rubber reinforced water-based adhesive obtained in Example 10 were performed. The results are as follows: Figure 1and Figure 2 The particle size distribution of the rubber-reinforced water-based adhesive obtained in Example 10 is shown in FIG. Figure 1 As shown, the increasing line is the cumulative distribution curve, showing that the cumulative content gradually increases with increasing particle size. When the particle size reaches approximately 1.0 μm, the cumulative content approaches 100%, indicating that the vast majority of adhesive particles are 1.0 μm or smaller. The other line (parabola) is the frequency distribution curve, which has a clear peak corresponding to particle sizes between approximately 0.2 and 0.3 μm, indicating that the adhesive particles in this size range are the most abundant.

[0128] Table 3 shows the corresponding content of adhesive particles with different particle sizes. It can be seen that when the particle size is 0.200 μm, the content is 28.89%; when the particle size is 0.500 μm, the content reaches 84.13%. When the particle size exceeds 2.000 μm, the content is 100%, indicating that adhesive particles larger than 2.000 μm are basically non-existent.

[0129] Table 3 Contents corresponding to different particle sizes

[0130] Particle size / μm content / % Particle size / μm content / % 0.100 7.69 5.000 100.00 0.200 28.93 10.000 100.00 0.500 94.13 20.000 100.00 1.000 98.81 45.000 100.00 2.000 100.00 75.000 100.00

[0131] As can be seen, the particle size distribution of the rubber-reinforced water-based adhesive of the present invention is relatively narrow, primarily concentrated in a smaller particle size range (approximately 0.2 to 0.5 μm). This indicates good particle size uniformity and demonstrates that the silane-coupling agent-modified SBS rubber bonds well with the water-based adhesive, which is beneficial for the adhesive's performance stability. Smaller and more uniform particle sizes generally result in better dispersibility, wettability, and bonding properties during use. For example, during use, the particles can be more evenly distributed on the adherend surface, thereby improving bond strength and consistency.

[0132] The electron microscope diagram of the rubber-reinforced water-based adhesive obtained in Example 10 is as follows: Figure 2 As shown, it can be seen that the adhesive particles are mostly spherical and relatively regular in shape, which helps them to be evenly dispersed in the system and spread better during coating; the particle size is relatively consistent overall, indicating that the particle size is well controlled during the preparation process, and adhesives with uniform particle size can provide more stable performance in application; no obvious impurities or foreign matter were observed, indicating that the adhesive has a high purity and the product quality is relatively reliable.

[0133] The particles are densely distributed and relatively uniform, with no obvious agglomeration or large voids, indicating that the SBS rubber modified with the silane coupling agent has achieved good fusion with the water-based adhesive, which is also beneficial to improving the cohesive strength of the adhesive and its wettability to the substrate, thereby improving the bonding effect.

Claims

1. A rubber-reinforced water-based adhesive, characterized in that: The composition is composed of the following raw materials in parts by weight: 19-36 parts of silane-modified SBS rubber, 10-20 parts of acrylic soft monomer, 8-15 parts of acrylic hard monomer, 5-13 parts of acrylic functional monomer, 1-3 parts of emulsifier, 0.2-0.8 parts of potassium persulfate and 40-60 parts of deionized water; The silane-modified SBS rubber is prepared according to the following steps: Dispersing the SBS rubber in the first allyl acrylate, stirring until the SBS rubber is dissolved, adding a silane coupling agent and benzoyl peroxide, stirring and heating to 78-82° C. and reacting for 2.5-3.5 hours to obtain a silane-modified SBS rubber; The mass ratio of SBS rubber, first allyl acrylate, silane coupling agent and benzoyl peroxide is 4-8:15-25:0.1-2:0.1-0.5; The silane coupling agent is a silane coupling agent containing a carbon-carbon double bond.

2. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane.

3. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The acrylic functional monomer is an acrylic self-crosslinking monomer, a second allyl acrylate or dimethylaminoethyl methacrylate.

4. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The acrylic soft monomer is one or two of 2-nonyl acrylate, 2-propylethyl acrylate or n-butyl acrylate.

5. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The acrylic hard monomer is one or two of benzyl methacrylate, tert-butyl 2-bromoacrylate or methyl α-chloroacrylate.

6. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The emulsifier is octylphenol polyoxyethylene ether or sodium lauryl sulfate.

7. The rubber-reinforced water-based adhesive according to claim 1, characterized in that: The model of the SBS rubber is YH-188, YH-501, YH-791, YH-792 or YH-796.

8. The method for preparing a rubber-reinforced water-based adhesive according to claim 1, characterized in that: The following steps are involved: ① In parts by weight, 10 to 20 parts of acrylic soft monomer, 8 to 15 parts of acrylic hard monomer, and 5 to 13 parts of acrylic functional monomer are mixed evenly to obtain a mixed monomer, which is set aside; ② Add 40-60 parts of deionized water, 19-36 parts of silane-modified SBS rubber, and 1-3 parts of emulsifier to a reactor, stir evenly, and then heat to 78-82° C., add the mixed monomer obtained in step ① dropwise to the reactor under stirring, and simultaneously add 0.2-0.8 parts of potassium persulfate dropwise to the reactor as an initiator, control the temperature of the reactor at 78-82° C. during the addition, and react for 1-2 hours after the addition is complete to obtain a rubber-reinforced water-based adhesive.

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