High temperature resistant VHB pressure sensitive adhesive and preparation method thereof

Abstract

The application belongs to the technical field of pressure sensitive adhesive, and discloses a high-temperature-resistant VHB pressure sensitive adhesive and a preparation method thereof. The high-temperature-resistant VHB pressure sensitive adhesive is composed of the following components with mass percentage: 45-70% of acrylic ester copolymer, 20-40% of silicone glue, 5-15% of crosslinking agent, 2-6% of thickening agent and 0.2-2% of catalyst. The preparation method is as follows: the acrylic ester copolymer is added into a reaction kettle, the silicone glue is gradually added under stirring condition, and then the crosslinking agent and the thickening agent are added, and the stirring is continued until the mixture is uniform, finally the catalyst is added and stirred until the mixture is uniform, and the high-temperature-resistant VHB pressure sensitive adhesive is obtained after being placed at a constant temperature of 50-80 DEG C for more than 24 hours until complete solidification. The VHB pressure sensitive adhesive of the application is prepared by mixing the acrylic ester copolymer with specific silicone glue, and has the advantages of strong bonding force and good high-temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of pressure-sensitive adhesive technology, specifically relating to a high-temperature resistant VHB pressure-sensitive adhesive and its preparation method. Background Technology

[0002] VHB (Very High Bond) pressure-sensitive adhesive is a high-strength, high-adhesion double-sided tape commonly used in the automotive, electronics, and construction industries. Existing VHB pressure-sensitive adhesives are primarily composed of polyacrylate, and their weather resistance and high-temperature resistance still need improvement.

[0003] Patent CN 106589221 A discloses a high-temperature resistant and die-cut-resistant pressure-sensitive adhesive, composed of a main monomer, an initiator, a crosslinking agent, and an organic solvent. The main monomer includes a soft monomer (acrylate), a hard monomer (methyl methacrylate), a crosslinking monomer (acrylic acid), and an organosilicon resin (vinyltrimethoxysilane, allyltrimethoxysilane, or 3-(methacryloyloxy)propyltrimethoxysilane). This pressure-sensitive adhesive possesses the common characteristics of both organosilicon and acrylic adhesives, exhibiting good film-forming properties, good adhesion (1000–2000 g / 25 mm), and excellent adhesion to the substrate. However, to enhance the compatibility between the organosilicon and acrylate components, a relatively large proportion of organic solvent needs to be added to this pressure-sensitive adhesive.

[0004] Patent CN 116041612 A discloses an acrylate copolymer base, a pressure-sensitive adhesive, and a method for preparing the same. This acrylate copolymer base also requires a relatively large amount of organic solvent to promote film formation and curing.

[0005] Patent CN 115960302 A discloses a pressure-sensitive adhesive composition comprising an acrylate copolymer, a tackifying resin, and a curing agent. The acrylate copolymer is composed of soft monomers, hard monomers, and functional monomers. The functional monomers include crosslinking monomers, hydrophobic monomers, cyclic monomers, and polar monomers. The crosslinking monomers are selected from one or a combination of at least two of acrylic acid, methacrylic acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate. The hydrophobic monomers are selected from one or a combination of at least two of tert-butyl acrylate, tert-butyl methacrylate, hexafluorobutyl acrylate, and tridecafluorooctyl acrylate. The cyclic monomers are selected from one or a combination of at least two of glycidyl methacrylate, N,N-dimethylacrylamide, N-vinylpyrrolidone, tetrahydrofuran acrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. This pressure-sensitive adhesive, through the rational selection and combination of soft monomers, hard monomers, and functional monomers, as well as the combination of tackifying resins with high softening points and medium-low softening points, can produce pressure-sensitive adhesive products (such as pressure-sensitive tapes) with excellent adhesion and high temperature and humidity (85℃*85%) anti-rebound properties. However, the composition of this pressure-sensitive adhesive is relatively complex and the cost is high. Summary of the Invention

[0006] In view of the shortcomings and deficiencies of the existing technology, the primary objective of this invention is to provide a high-temperature resistant VHB pressure-sensitive adhesive.

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned high-temperature resistant VHB pressure-sensitive adhesive.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A high-temperature resistant VHB pressure-sensitive adhesive, composed of the following components in weight percentage:

[0010]

[0011] Furthermore, the acrylate copolymer is a terpolymer of MMA / BA / AA (methyl methacrylate / butyl acrylate / acrylic acid) or a quaternary copolymer of MMA / BA / AA / HEMA (methyl methacrylate / butyl acrylate / acrylic acid / hydroxyethyl methacrylate).

[0012] Preferably, the solid content of the acrylate copolymer is 40% to 70%, and the viscosity at 25°C is 2000 to 10000 mPa·s.

[0013] Furthermore, the silicone rubber is prepared by the following method:

[0014] 107 glue (α,ω-dihydroxy polysiloxane) was stirred and mixed evenly with dimethyl silicone oil. Then, aminosilane coupling agent and long-chain alkylsilane coupling agent were added, and a hydrolysis crosslinking reaction was carried out under humid air conditions to obtain organosilicon.

[0015] Preferably, the viscosity of the 107 adhesive and dimethyl silicone oil at 25°C is 50–1000 mPa·s; the mass ratio of the 107 adhesive to the dimethyl silicone oil is 3–6:1.

[0016] Preferably, the aminosilane coupling agent is at least one selected from aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and γ-aminoethylaminopropyltrimethoxysilane. The amount of aminosilane coupling agent added is 2% to 4% of the mass of the 107 adhesive.

[0017] Preferably, the long-chain alkylsilane coupling agent refers to a C12-C18 alkyltrimethoxysilane. The amount of long-chain alkylsilane coupling agent added is 3% to 6% of the mass of the 107 adhesive.

[0018] The silicone of the present invention is a hydroxyl polysiloxane crosslinked with an aminosilane coupling agent and a long-chain alkylsilane coupling agent, which has improved compatibility with acrylate copolymers; at the same time, its grafted amino groups can also undergo crosslinking reactions with the carboxyl groups contained in the acrylate copolymer and the carboxyl groups in crosslinking agents such as acrylic acid, thereby improving compatibility and cohesive strength.

[0019] Furthermore, the crosslinking agent is at least one of acrylic acid and methacrylic acid.

[0020] Furthermore, the thickener is at least one of terpene tackifying resin, phenolic tackifying resin, phenolic modified tackifying resin, rosin tackifying resin, and petroleum tackifying resin.

[0021] Further, the catalyst is an organic peroxide catalyst or an azo catalyst; the organic peroxide catalyst is preferably benzoyl peroxide, and the azo catalyst is preferably at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

[0022] The preparation method of the above-mentioned high-temperature resistant VHB pressure-sensitive adhesive includes the following preparation steps:

[0023] (1) Add the acrylic acid copolymer to the reactor and gradually add the silicone rubber while stirring until the mixture is homogeneous.

[0024] (2) Add crosslinking agent and thickener to the mixed adhesive solution in step (1) and continue stirring until the mixture is uniform;

[0025] (3) Add the catalyst to the mixed adhesive solution in step (2) and stir to mix evenly. Then place it at a constant temperature of 50-80℃ for more than 24 hours to allow it to fully cure, and obtain the high temperature resistant VHB pressure-sensitive adhesive.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The VHB pressure-sensitive adhesive of the present invention is made by mixing acrylate copolymer with a specific organic silicone, which has the advantages of high temperature resistance of organic silicone and good film-forming properties and adhesion of acrylate copolymer.

[0028] (2) The silicone of the present invention is a hydroxyl polysiloxane crosslinked with an aminosilane coupling agent and a long-chain alkylsilane coupling agent, which has improved compatibility with acrylate copolymers; at the same time, the grafted amino groups can also crosslink with the carboxyl groups contained in the acrylate copolymer and the carboxyl groups in crosslinking agents such as acrylic acid, thereby improving compatibility and cohesive strength and improving the adhesion of VHB pressure-sensitive adhesive. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0030] Example 1

[0031] This embodiment of a high-temperature resistant VHB pressure-sensitive adhesive is composed of the following components in weight percentage:

[0032] MMA / BA / AA terpolymer (45% solids content, viscosity at 25°C 3500 mPa·s) 45% (based on solids content); silicone 40%; acrylic crosslinking agent 10%; thickener terpene tackifying resin 4%; catalyst benzoyl peroxide 1%.

[0033] The preparation method of the high-temperature resistant VHB pressure-sensitive adhesive includes the following preparation steps:

[0034] (1) Weigh each component according to the above mass percentage content, add the MMA / BA / AA terpolymer to the reactor, and gradually add the silicone under stirring conditions and stir until uniform;

[0035] (2) Add acrylic crosslinking agent and thickener terpene tackifying resin to the mixed adhesive solution in step (1) and continue stirring until the mixture is uniform;

[0036] (3) Add benzoyl peroxide catalyst to the mixed adhesive solution in step (2) and stir to mix evenly. Then place it at a constant temperature of 50-80℃ for more than 24 hours to allow it to fully cure, and obtain the high temperature resistant VHB pressure-sensitive adhesive.

[0037] The silicone rubber described in this embodiment is prepared by the following method:

[0038] 107 glue (α,ω-dihydroxy polysiloxane with a viscosity of 150 mPa·s at 25℃) and dimethyl silicone oil (viscosity of 300 mPa·s at 25℃) were stirred and mixed evenly. The mass ratio of 107 glue to dimethyl silicone oil was 4:1. Then, 3% by weight of aminopropyltrimethoxysilane coupling agent and 5% by weight of dodecyltrimethoxysilane coupling agent were added to 107 glue. The mixture was heated to 60℃ under humid air conditions for 2 hours to carry out a hydrolysis and crosslinking reaction to obtain silicone.

[0039] Example 2

[0040] This embodiment of a high-temperature resistant VHB pressure-sensitive adhesive is composed of the following components in weight percentage:

[0041] MMA / BA / AA terpolymer (55% solids content, viscosity at 25°C 6000 mPa·s) 55% (based on solids content); silicone 30%; acrylic crosslinking agent 10%; thickener terpene tackifying resin 4%; catalyst benzoyl peroxide 1%.

[0042] The preparation method of the high-temperature resistant VHB pressure-sensitive adhesive is the same as that in Example 1.

[0043] The silicone rubber described in this embodiment is prepared by the following method:

[0044] 107 adhesive (α,ω-dihydroxy polysiloxane with a viscosity of 150 mPa·s at 25℃) and dimethyl silicone oil (viscosity of 450 mPa·s at 25℃) were stirred and mixed evenly. The mass ratio of 107 adhesive to dimethyl silicone oil was 5:1. Then, 2% γ-aminoethylaminopropyltrimethoxysilane coupling agent and 6% octadecyltrimethoxysilane coupling agent by mass of 107 adhesive were added. The mixture was heated to 60℃ under humid air conditions for 2 hours to carry out a hydrolysis and crosslinking reaction to obtain silicone.

[0045] Example 3

[0046] This embodiment of a high-temperature resistant VHB pressure-sensitive adhesive is composed of the following components in weight percentage:

[0047] MMA / BA / AA terpolymer (70% solids content, viscosity at 25°C 9000 mPa·s) 70% (based on solids content); silicone 20%; methacrylic acid crosslinking agent 6%; thickener rosin tackifying resin 3%; catalyst dimethyl azobisisobutyrate 1%.

[0048] The preparation method of the high-temperature resistant VHB pressure-sensitive adhesive is the same as that in Example 1.

[0049] The silicone rubber described in this embodiment is prepared by the following method:

[0050] 107 glue (α,ω-dihydroxy polysiloxane with a viscosity of 150 mPa·s at 25℃) and dimethyl silicone oil (viscosity of 500 mPa·s at 25℃) were stirred and mixed evenly. The mass ratio of 107 glue to dimethyl silicone oil was 3:1. Then, 4% by weight of aminopropyltriethoxysilane coupling agent and 3% by weight of dodecyltrimethoxysilane coupling agent were added to 107 glue. The mixture was heated to 70℃ under humid air conditions and subjected to a hydrolysis and crosslinking reaction for 3 hours to obtain silicone.

[0051] Example 4

[0052] This embodiment of a high-temperature resistant VHB pressure-sensitive adhesive is composed of the following components in weight percentage:

[0053] MMA / BA / AA / HEMA quaternary copolymer (55% solids content, viscosity at 25°C 6000 mPa·s) 55% (based on solids content); silicone 35%; acrylic crosslinking agent 5%; thickener petroleum tackifying resin 4.5%; catalyst dimethyl azobisisobutyrate 0.5%.

[0054] The preparation method of the high-temperature resistant VHB pressure-sensitive adhesive is the same as that in Example 1.

[0055] The preparation method of the silicone in this embodiment is the same as that in Example 2.

[0056] The high-temperature resistant VHB pressure-sensitive adhesives obtained in the above embodiments were subjected to peel strength tests (GB2792-81) and high-temperature resistance tests (peel strength was tested after 200 hours in an 80℃ constant temperature chamber). Five test samples were set up for each test, and the average value was taken. The test results are shown in Table 1 below.

[0057] Table 1

[0058] Test sample / test item Peel strength Peel strength at 80℃ / 200h Example 1 19.6N / 25mm 18.2N / 25mm Example 2 20.5N / 25mm 19.0N / 25mm Example 3 19.2N / 25mm 17.5N / 25mm Example 4 21.1N / 25mm 19.7N / 25mm

[0059] The results above show that the VHB pressure-sensitive adhesive obtained by the present invention has good adhesion and high temperature resistance. After treatment at 80℃ for 200h, its peel strength can still maintain more than 90%.

[0060] Comparative Example 1

[0061] This comparative example of a VHB pressure-sensitive adhesive, compared to Example 2, does not contain silicone and consists of the following components in weight percentage:

[0062] 85% MMA / BA / AA terpolymer (55% solids content, viscosity 6000 mPa·s at 25°C); 10% acrylic crosslinking agent; 4% terpene tackifying resin thickener; 1% benzoyl peroxide catalyst.

[0063] The peel strength of the VHB pressure-sensitive adhesive obtained in this comparative example was tested to be 14.8 N / 25 mm, and the peel strength at 80℃ / 200 h was 10.5 N / 25 mm.

[0064] The results above show that by adding specific silicone, the present invention can significantly improve the bonding strength and high temperature resistance of VHB pressure-sensitive adhesive.

[0065] Comparative Example 2

[0066] This comparative example of a VHB pressure-sensitive adhesive uses an equal amount of vinyltrimethoxysilane instead of silicone resin in place of silicone in Example 2, while the rest remains the same.

[0067] The peel strength of the VHB pressure-sensitive adhesive obtained in this comparative example was tested to be 15.3 N / 25 mm, and the peel strength at 80℃ / 200 h was 11.4 N / 25 mm.

[0068] The results above show that directly using vinyl-containing silane compounds has a limited effect on improving the bonding strength and high-temperature resistance of acrylate pressure-sensitive adhesives.

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high temperature resistant VHB pressure sensitive adhesive, characterized in that, consists of the following components by mass percentage: acrylate copolymer 45%~70%; silicone gel 20%~40%; crosslinking agent 5%~15%; thickening agent 2%~6%; catalyst 0.2%~2%; the silicone gel is prepared by the following method: 107 glue is mixed with dimethyl silicone oil, then amino silane coupling agent and long-chain alkyl silane coupling agent are added, and hydrolysis crosslinking reaction is carried out under humid air conditions to obtain silicone gel; the mass ratio of 107 glue to dimethyl silicone oil is 3~6:1; the amino silane coupling agent refers to at least one of aminopropyl trimethoxysilane, aminopropyl triethoxysilane and γ-aminoethyl aminopropyl trimethoxysilane, and the addition amount of amino silane coupling agent is 2%~4% of the mass of 107 glue; the long-chain alkyl silane coupling agent refers to alkyl trimethoxysilane with C12~C18, and the addition amount of long-chain alkyl silane coupling agent is 3%~6% of the mass of 107 glue; the crosslinking agent is at least one of acrylic acid and methacrylic acid.

2. The high temperature resistant VHB pressure sensitive adhesive according to claim 1, characterized in that, the acrylate copolymer is MMA / BA / AA terpolymer or MMA / BA / AA / HEMA quaternary copolymer.

3. The high temperature resistant VHB pressure sensitive adhesive according to claim 2, characterized in that, the solid content of the acrylate copolymer is 40%~70%, and the viscosity at 25℃ is 2000~10000 mPa.s.

4. The high temperature resistant VHB pressure sensitive adhesive according to claim 1, characterized in that, the viscosity of 107 glue and dimethyl silicone oil at 25℃ is 50~1000 mPa.s.

5. The high temperature resistant VHB pressure sensitive adhesive according to claim 1, wherein, the thickening agent is at least one of terpene tackifying resin, phenolic tackifying resin, phenolic modified tackifying resin, rosin tackifying resin and petroleum tackifying resin.

6. The high temperature resistant VHB pressure sensitive adhesive according to claim 1, wherein, the catalyst is organic peroxide catalyst or azo catalyst; the organic peroxide catalyst is dibenzoyl peroxide, and the azo catalyst is at least one of azobis isobutyronitrile, azobis isoheptyl nitrile and dimethyl azobis isobutyrate.

7. The method for preparing a high temperature resistant VHB pressure sensitive adhesive according to any one of claims 1-6, characterized in that, comprises the following preparation steps: (1) the acrylate copolymer is added to the reaction kettle, and the silicone gel is gradually added under stirring conditions and stirred to mix uniformly; (2) the crosslinking agent and the thickening agent are added to the mixed glue solution of step (1), and continue to stir until mixed uniformly; (3) the catalyst is added to the mixed glue solution of step (2) and stirred to mix uniformly, then placed at a constant temperature of 50~80℃ for more than 24h until completely cured to obtain the high-temperature-resistant VHB pressure-sensitive adhesive.

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