High-adhesion composite adhesive

Abstract

The invention relates to a high-adhesion composite adhesive and a preparation method thereof, and belongs to the technical field of adhesives. The high-adhesion composite adhesive is prepared from the following components in parts by weight: 34 to 45 parts of acrylate emulsion, 20 to 26 parts of reactive monomer, 5 to 8 parts of modified carboxylic butadiene-styrene latex, 1.0 to 1.5 parts of photoinitiator, 0.1 to 0.3 part of silane coupling agent, 0.2 to 0.5 part of antioxidant, 0.3 to 0.5 part of defoaming agent and 20 to 28 parts of deionized water. The composite adhesive prepared by the invention realizes double improvement of film forming uniformity and phase stability by virtue of a multi-component synergistic effect, and the problems of layering and debonding are not easy to occur after long-term use.

Description

Technical Field

[0001] This invention belongs to the technical field of adhesives, and relates to a high-adhesion composite adhesive and its preparation method. Background Technology

[0002] In existing hook adhesive technologies, most products use a single adhesive system. Common single acrylic adhesives, silicone adhesives, or pressure-sensitive adhesives have significant performance shortcomings: if a strong adhesive with high cohesive strength is used, the initial tack is often insufficient, and the hook is prone to shifting and falling off in the initial stage of fixing; if a weak adhesive or pressure-sensitive adhesive with excellent initial tack is used, the long-term load-bearing capacity is poor, unable to support weights of more than 50 catties, let alone meet the high load-bearing requirements of 70 catties. Some attempts to increase the load-bearing capacity by increasing the amount of adhesive used will result in stress concentration and uneven film formation due to an excessively thick adhesive layer, which will reduce the bonding stability.

[0003] Gelatin, a natural polymer derived from collagen, possesses various functional groups, such as amino, hydroxyl, amide, and carboxyl groups. It has a wide molecular weight distribution, is soluble in hot water, is abundant, inexpensive, non-toxic, and easy to process, making it a promising candidate for use in adhesives. In the field of polymer science, chemically modifying the active groups on the gelatin molecular chain or combining it with other polymers can effectively improve its mechanical and adhesive properties. Summary of the Invention

[0004] The purpose of this invention is to provide a high-adhesion composite adhesive and its preparation method. The composite adhesive prepared by this invention achieves a dual improvement in film uniformity and phase stability through the synergistic effect of multiple components, and is not prone to delamination or debonding problems during long-term use.

[0005] The objective of this invention can be achieved through the following technical solutions: A high-adhesion composite adhesive comprises the following components in parts by weight: The composition includes 34-45 parts acrylate emulsion, 20-26 parts reactive monomer, 5-8 parts modified carboxylated styrene-butadiene latex, 1.0-1.5 parts photoinitiator, 0.1-0.3 parts silane coupling agent, 0.2-0.5 parts antioxidant, 0.3-0.5 parts defoamer, and 20-28 parts deionized water.

[0006] As a preferred technical solution of the present invention, a method for preparing a high-adhesion composite adhesive includes the following steps: adding acrylate emulsion, reactive monomer, modified carboxylated styrene-butadiene latex and photoinitiator into a reaction vessel, stirring at 400-500 r / min for 1.5-2.0 h, then adding silane coupling agent, antioxidant, defoamer and deionized water, and continuing to stir at 600-800 r / min for 2-3 h to obtain the high-adhesion composite adhesive.

[0007] As a preferred embodiment of the present invention, the solid content of the acrylate emulsion is 45-50%.

[0008] As a preferred embodiment of the present invention, the reaction monomer is composed of acrylic acid and triethylene glycol diacrylate mixed in a mass ratio of 5.2-6.0:0.8-1.2.

[0009] As a preferred embodiment of the present invention, the photoinitiator is one or both of photoinitiator 1173 and photoinitiator TPO. Preferably, the photoinitiator is a mixture of photoinitiator 1173 and photoinitiator TPO in a mass ratio of 2:1.

[0010] As a preferred embodiment of the present invention, the silane coupling agent is silane coupling agent KH570.

[0011] As a preferred embodiment of the present invention, the antioxidant is one or more of antioxidant 168, antioxidant 1010, antioxidant 1076 and antioxidant 1079.

[0012] As a preferred embodiment of the present invention, the defoamer is BYK019.

[0013] As a preferred embodiment of the present invention, the preparation of the modified carboxylated styrene-butadiene latex includes the following steps: 1) After preheating deionized water, slowly add gelatin while stirring, let stand, stir at a constant temperature, and degas under vacuum to obtain a gelatin solution. 2) Stir the carboxylated styrene-butadiene latex and emulsifier, adjust the pH value, and slowly add it to the gelatin solution under an inert gas atmosphere. Heat and stir, and after cooling, add the modification solution and continue stirring to obtain modified carboxylated styrene-butadiene latex.

[0014] As a preferred embodiment of the present invention, the preheating temperature in step 1) is 45-50℃, the stirring speed is 180-240rpm, the settling time is 30-45min, the constant temperature stirring temperature is 55℃, the stirring speed is 300-350rpm, the stirring time is 1.0-1.5h, and the vacuum degassing time is 15-20min.

[0015] As a preferred embodiment of the present invention, the ratio of gelatin to deionized water in step 1) is 22-25g: 330-380g.

[0016] As a preferred embodiment of the present invention, in step 2), the pH value is adjusted to neutral, the inert gas atmosphere is a nitrogen atmosphere, the heating and stirring temperature is 50-55℃, the stirring speed is 250-300rpm, and the stirring time is 30-45min, and the continuing stirring temperature is 40-45℃ and the stirring time is 3-4h.

[0017] As a preferred embodiment of the present invention, the ratio of the amount of carboxylated styrene-butadiene latex, emulsifier, gelatin solution and modified solution in step 2) is 30-35g: 0.06-0.10g: 700-750g: 135-140g, and the emulsifier is Tween-80.

[0018] As a preferred embodiment of the present invention, the preparation of the modified solution includes: mixing 2-(mercaptomethyl)pentanediic acid and deionized water, slowly adding acrolein and an initiator under an inert gas atmosphere and stirring at a constant temperature, adjusting the pH value to obtain the modified solution.

[0019] As a preferred embodiment of the present invention, in the preparation of the modified solution, the inert gas atmosphere is a nitrogen atmosphere, and the ratio of 2-(mercaptomethyl)pentanediic acid, acrolein and deionized water is 9-11g:3.4-4.0g:120-130mL.

[0020] As a preferred embodiment of the present invention, the constant temperature stirring is performed at a temperature of 50-55℃ for 2.5-3.0 hours, followed by stirring at a temperature of 60-70℃ for 30-40 minutes, and the pH adjustment is performed to adjust the pH value to neutral.

[0021] In a preferred embodiment of the present invention, the high-adhesion composite adhesive is disposed on a rigid PVC substrate. The rigid PVC substrate is sequentially provided with the high-adhesion composite adhesive, a stretchable film layer, a rubber-type hook adhesive layer, and a release film layer, with thicknesses of 0.3 mm, 0.232 mm, 0.088 mm, 0.08 mm, and 0.05 mm, respectively. Traditional films cannot withstand a force of 80 catties, while the five-layer structure film prepared by this invention possesses this load-bearing capacity. Traditional films often use acrylic foam adhesive during manufacturing, which suffers from weak adhesion and easy detachment; if rubber adhesive is used, breakage is likely, and the load-bearing capacity is insufficient. In this solution, the stretchable film is located in the middle layer, serving to isolate the strong adhesive from the weak adhesive.

[0022] The beneficial effects of this invention are: 1. The composite adhesive prepared by this invention achieves a dual improvement in film uniformity and phase stability through the synergistic effect of multiple components, and is not prone to delamination or debonding problems during long-term use.

[0023] 2. The composite adhesive prepared by this invention has strong adaptability to composite interfaces of different materials, strong adhesion and excellent instant bonding effect, which can meet the usage requirements of high adhesion conditions.

[0024] 3. The composite adhesive has balanced mechanical properties, with both good cohesive strength and flexibility. Its overall stability and durability are superior to conventional water-based compound adhesives. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below. Example 1

[0026] The preparation of the modified carboxylated styrene-butadiene latex includes the following steps: 1) After preheating deionized water to 45°C, gelatin is slowly added while stirring at 180 rpm. The mixture is allowed to stand for 30 minutes, then stirred at 55°C and 300 rpm for 1.0 h, followed by vacuum degassing for 15 minutes to obtain a gelatin solution. The ratio of gelatin to deionized water is 22 g: 330 g. 2) Mix the carboxylated styrene-butadiene latex and emulsifier, adjust the pH to neutral, and slowly add the mixture to the gelatin solution under a nitrogen atmosphere. Heat and stir at 50°C and 250 rpm for 30 minutes. After cooling to room temperature, add the modification solution and continue stirring at 40°C for 3 hours to obtain the modified carboxylated styrene-butadiene latex. The ratio of carboxylated styrene-butadiene latex, emulsifier, gelatin solution and modification solution is 30g:0.06g:700g:135g, and the emulsifier is Tween-80.

[0027] The preparation of the modified solution includes: mixing 2-(mercaptomethyl)pentanediic acid and deionized water, slowly adding acrolein and an initiator under a nitrogen atmosphere, stirring at 50°C for 2.5 h, raising the temperature to 60°C and stirring for another 30 min, adjusting the pH to neutral to obtain the modified solution; the ratio of 2-(mercaptomethyl)pentanediic acid, acrolein and deionized water is 9 g: 3.4 g: 120 mL.

[0028] A high-adhesion composite adhesive comprises the following components in parts by weight: The mixture contains 34 parts acrylate emulsion, 20 parts reactive monomer, 5 parts modified carboxylated styrene-butadiene latex, 1.0 part photoinitiator, 0.1 part silane coupling agent, 0.2 parts antioxidant, 0.3 parts defoamer, and 20 parts deionized water.

[0029] A method for preparing a high-adhesion composite adhesive includes the following steps: adding acrylate emulsion, reactive monomer, modified carboxylated styrene-butadiene latex and photoinitiator into a reaction vessel, stirring at 400 r / min for 1.5 h, then adding silane coupling agent, antioxidant, defoamer and deionized water, and continuing to stir at 600 r / min for 2 h to obtain the high-adhesion composite adhesive.

[0030] The reactive monomer is a mixture of acrylic acid and triethylene glycol diacrylate in a mass ratio of 5.2:0.8; The photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO mixed in a mass ratio of 2:1; The silane coupling agent is silane coupling agent KH570; The antioxidant is antioxidant 1010; The defoamer is BYK019. Example 2

[0031] The preparation of the modified carboxylated styrene-butadiene latex includes the following steps: 1) After preheating deionized water to 48°C, gelatin is slowly added while stirring at 210 rpm. The mixture is allowed to stand for 38 minutes, then stirred at 55°C and 325 rpm for 1.2 hours and vacuum degassing for 18 minutes to obtain a gelatin solution. The ratio of gelatin to deionized water is 24 g: 355 g. 2) Mix the carboxylated styrene-butadiene latex and emulsifier, adjust the pH to neutral, and slowly add the mixture to the gelatin solution under a nitrogen atmosphere. Heat and stir at 52°C and 275 rpm for 38 minutes. After cooling to room temperature, add the modification solution and continue stirring at 42°C for 3.5 hours to obtain the modified carboxylated styrene-butadiene latex. The ratio of carboxylated styrene-butadiene latex, emulsifier, gelatin solution and modification solution is 32g:0.08g:725g:138g, and the emulsifier is Tween-80.

[0032] The preparation of the modified solution includes: mixing 2-(mercaptomethyl)pentanediic acid and deionized water, slowly adding acrolein and an initiator under a nitrogen atmosphere, stirring at 52°C for 2.8 h, raising the temperature to 65°C and stirring for another 35 min, adjusting the pH to neutral to obtain the modified solution; the ratio of 2-(mercaptomethyl)pentanediic acid, acrolein and deionized water is 10 g: 3.8 g: 125 mL.

[0033] A high-adhesion composite adhesive comprises the following components in parts by weight: The mixture consists of 40 parts acrylic emulsion, 23 parts reactive monomers, 6 parts modified carboxylated styrene-butadiene latex, 1.2 parts photoinitiator, 0.2 parts silane coupling agent, 0.4 parts antioxidant, 0.4 parts defoamer, and 24 parts deionized water.

[0034] A method for preparing a high-adhesion composite adhesive includes the following steps: adding acrylate emulsion, reactive monomers, modified carboxylated styrene-butadiene latex and photoinitiator into a reaction vessel, stirring at 450 r / min for 1.8 h, then adding silane coupling agent, antioxidant, defoamer and deionized water, and continuing to stir at 700 r / min for 2.5 h to obtain the high-adhesion composite adhesive.

[0035] The reactive monomer is a mixture of acrylic acid and triethylene glycol diacrylate in a mass ratio of 5.6:1; The photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO mixed in a mass ratio of 2:1; The silane coupling agent is silane coupling agent KH570; The antioxidant is antioxidant 1010; The defoamer is BYK019. Example 3

[0036] The preparation of the modified carboxylated styrene-butadiene latex includes the following steps: 1) After preheating deionized water to 50°C, gelatin is slowly added while stirring at 240 rpm. The mixture is allowed to stand for 45 minutes, then stirred at 55°C and 350 rpm for 1.5 hours and vacuum degassing for 20 minutes to obtain a gelatin solution. The ratio of gelatin to deionized water is 25 g: 380 g. 2) Mix the carboxylated styrene-butadiene latex and emulsifier, adjust the pH to neutral, and slowly add the mixture to the gelatin solution under a nitrogen atmosphere. Heat and stir at 55°C and 300 rpm for 45 minutes. After cooling to room temperature, add the modification solution and continue stirring at 45°C for 4 hours to obtain the modified carboxylated styrene-butadiene latex. The ratio of carboxylated styrene-butadiene latex, emulsifier, gelatin solution and modification solution is 35g:0.10g:750g:140g, and the emulsifier is Tween-80.

[0037] The preparation of the modified solution includes: mixing 2-(mercaptomethyl)pentanediic acid and deionized water, slowly adding acrolein and an initiator under a nitrogen atmosphere, stirring at 55°C for 3.0 h, raising the temperature to 70°C and stirring for another 40 min, adjusting the pH to neutral to obtain the modified solution; the ratio of 2-(mercaptomethyl)pentanediic acid, acrolein and deionized water is 11 g: 4.0 g: 130 mL.

[0038] A high-adhesion composite adhesive comprises the following components in parts by weight: The mixture consists of 45 parts acrylic emulsion, 26 parts reactive monomers, 8 parts modified carboxylated styrene-butadiene latex, 1.5 parts photoinitiator, 0.3 parts silane coupling agent, 0.5 parts antioxidant, 0.5 parts defoamer, and 28 parts deionized water.

[0039] A method for preparing a high-adhesion composite adhesive includes the following steps: adding acrylate emulsion, reactive monomer, modified carboxylated styrene-butadiene latex and photoinitiator into a reaction vessel, stirring at 500 r / min for 2.0 h, then adding silane coupling agent, antioxidant, defoamer and deionized water, and continuing to stir at 800 r / min for 3 h to obtain the high-adhesion composite adhesive.

[0040] The reactive monomer is a mixture of acrylic acid and triethylene glycol diacrylate in a mass ratio of 6.0:1.2; The photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO mixed in a mass ratio of 2:1; The silane coupling agent is silane coupling agent KH570; The antioxidant is antioxidant 1010; The defoamer is BYK019.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 does not use 2-(mercaptomethyl)pentanediol, but all other aspects are the same.

[0042] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 does not use acrolein, but all other aspects are the same.

[0043] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that Comparative Example 3 does not use gelatin, but all other aspects are the same.

[0044] Comparative Example 4 The difference between this example and Example 3 is that step 2) of Comparative Example 4 is as follows: 2) Under a nitrogen atmosphere, add gelatin solution and heat and stir at 55℃ and 300rpm for 45min. After cooling to room temperature, add modification solution and continue stirring at 45℃ for 4h to obtain a mixture. Stir carboxylated styrene-butadiene latex and emulsifier together, adjust the pH to neutral and add to the mixture to obtain modified carboxylated styrene-butadiene latex. Everything else is the same.

[0045] The following performance tests were performed on Examples 1-3 and Comparative Examples 1-4 respectively.

[0046] Elongation at break test: Elongation at break is tested according to GB / T16777-2008; Adhesion test: in accordance with GB / T 4852-2002 and GB / T 4851-2014; The test results are shown in Table 1.

[0047] Table 1 Sample Performance Test Data As can be seen from the test results in Table 1, compared with Comparative Examples 1-4, the composite adhesive prepared by the present invention has excellent mechanical properties and high adhesion.

[0048] This invention utilizes the flexible styrene-butadiene segments and side-chain carboxyl functional groups of carboxylated styrene-butadiene latex, combined with gelatin, a polypeptide polymer containing primary amino, hydroxyl, and carboxyl groups. Through hydrogen bonding between polar functional groups and segment interpenetration, an interpenetrating physical network structure is constructed. This physical network forms the basic continuous phase of the adhesive, enhancing the dispersion stability, film uniformity, and matrix cohesion of the latex system. The thiol functional group in 2-(mercaptomethyl)pentanediol can undergo a highly efficient thiol / alkenyl click reaction with the carbon-carbon unsaturated double bonds in acrolein molecules, generating a polycarboxyl-modified solution retaining the aldehyde group. The aldehyde group can further react with the amino groups of gelatin through a Schiff base reaction, forming stable chemical covalent bonds. This achieves covalent anchoring of the chemically modified segments to the gelatin molecular chain, fixing them onto the physical interpenetrating network framework formed by gelatin / carboxylated styrene-butadiene latex, creating a composite crosslinking network with synergistic physical and covalent crosslinking. This composite network structure can tightly bind the latex elastic phase, gelatin polar phase, and polycarboxyl modified phase. Combined with acrylate emulsion and reactive monomers, it can be cured by ultraviolet crosslinking under the action of photoinitiator. This not only improves the cohesive strength, tensile and elongation at break of the adhesive layer, but also enhances the interfacial adhesion through the interaction of multifunctional polar sites and covalent bonds. At the same time, it optimizes the initial tack and holding power, ultimately achieving high adhesion and high mechanical stability of the composite adhesive.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-adhesion composite adhesive, characterized in that, The following components are included by weight: The composition includes 34-45 parts of acrylate emulsion, 20-26 parts of reactive monomers, 5-8 parts of modified carboxylated styrene-butadiene latex, 1.0-1.5 parts of photoinitiator, 0.1-0.3 parts of silane coupling agent, 0.2-0.5 parts of antioxidant, 0.3-0.5 parts of defoamer, and 20-28 parts of deionized water. The preparation of the modified carboxylated styrene-butadiene latex includes the following steps: 1) After preheating deionized water, slowly add gelatin while stirring, let stand, stir at a constant temperature, and degas under vacuum to obtain a gelatin solution. 2) Stir the carboxylated styrene-butadiene latex and emulsifier, adjust the pH value, and slowly add it to the gelatin solution under an inert gas atmosphere. Heat and stir, and after cooling, add the modification solution and continue stirring to obtain modified carboxylated styrene-butadiene latex.

2. The high-adhesion composite adhesive according to claim 1, characterized in that: The reactive monomer is a mixture of acrylic acid and triethylene glycol diacrylate in a mass ratio of 5.2-6.0:0.8-1.2, and the photoinitiator is one or both of photoinitiator 1173 and photoinitiator TPO.

3. The high-adhesion composite adhesive according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 168, antioxidant 1010, antioxidant 1076 and antioxidant 1079.

4. The high-adhesion composite adhesive according to claim 1, characterized in that: Step 1) The preheating temperature is 45-50℃, the stirring speed is 180-240rpm, the constant temperature stirring temperature is 55℃, the stirring speed is 300-350rpm, the stirring time is 1.0-1.5h, and the ratio of gelatin to deionized water is 22-25g:330-380g.

5. The high-adhesion composite adhesive according to claim 1, characterized in that: Step 2) The heating and stirring temperature is 50-55℃, the stirring speed is 250-300rpm, and the stirring time is 30-45min. The continued stirring temperature is 40-45℃, and the stirring time is 3-4h. The ratio of carboxylated styrene-butadiene latex, emulsifier, gelatin solution, and modified solution is 30-35g: 0.06-0.10g: 700-750g: 135-140g.

6. The high-adhesion composite adhesive according to claim 1, characterized in that: The preparation of the modified solution includes: mixing 2-(mercaptomethyl)pentanediic acid and deionized water, slowly adding acrolein and an initiator under an inert gas atmosphere and stirring at a constant temperature, adjusting the pH value to obtain the modified solution.

7. The high-adhesion composite adhesive according to claim 6, characterized in that: The ratio of 2-(mercaptomethyl)pentanediic acid, acrolein, and deionized water is 9-11g:3.4-4.0g:120-130mL. The constant temperature stirring is carried out at 50-55℃ for 2.5-3.0h, followed by stirring at 60-70℃ for 30-40min.

8. The high-adhesion composite adhesive according to claim 1, characterized in that: A method for preparing a high-adhesion composite adhesive includes the following steps: adding acrylate emulsion, reactive monomer, modified carboxylated styrene-butadiene latex and photoinitiator into a reaction vessel and stirring, then adding silane coupling agent, antioxidant, defoamer and deionized water and continuing stirring to obtain the high-adhesion composite adhesive.

9. The high-adhesion composite adhesive according to claim 1, characterized in that: The high-adhesion composite adhesive is disposed on a rigid PVC substrate, and the rigid PVC substrate is sequentially disposed with the high-adhesion composite adhesive, a stretchable film layer, a rubber hook adhesive layer and a release film layer, with thicknesses of 0.3 mm, 0.232 mm, 0.088 mm, 0.08 mm and 0.05 mm respectively.

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