Thermal visbreaking pressure-sensitive adhesive tape and preparation method thereof

Abstract

The invention discloses a thermal visbreaking pressure-sensitive adhesive tape and a preparation method thereof.The adhesive tape comprises a release layer, a thermal visbreaking layer and a base material layer which are sequentially arranged in a stacked mode, and the thermal visbreaking layer is obtained by coating thermal visbreaking glue and then curing the thermal visbreaking glue; the heat-reduced adhesive comprises the following raw material components in parts by weight: 90-120 parts of acrylate copolymer resin, 5-15 parts of modified resin, 0.01-1 part of a curing agent, 2-10 parts of modified thermal expansion microspheres and 20-60 parts of a solvent. The modified thermal expansion microspheres are specially modified, so that the compatibility and weather resistance of the modified thermal expansion microspheres in an acrylate pressure-sensitive adhesive can be improved, and the thermal viscosity-reducing adhesive prepared by adding the modified thermal expansion microspheres into an acrylate copolymer resin has excellent normal-temperature adhesive force which is not inferior to normal adhesive tape adhesion; and after the adhesive tape particles are expanded at a proper temperature, controllable viscosity reduction and even viscosity loss requirements can be met, and no residual adhesive is generated on the surface of an adhered object.

Description

Technical Field

[0001] The invention relates to the field of adhesive tape materials, and in particular to a heat-resistant adhesive tape and a preparation method thereof. Background Art

[0002] With the development of the electronic information industry in recent years, semiconductor components and electronic devices have become smaller, thinner and lighter, and are extremely vulnerable to damage during processing and transportation. Pressure-sensitive adhesives can temporarily fix and protect these electronic components. After the transportation or processing process is completed, how to easily detach the pressure-sensitive adhesive from the adhered object is a research focus. The viscosity of ordinary tapes will change significantly within the temperature range of -10℃-120℃, but the viscosity attenuation is not enough to easily detach from the adhered object. As a pressure-sensitive adhesive with adjustable peel strength, the viscosity-reducing pressure-sensitive adhesive can be easily removed after processing, so that the electronic components can be torn off without damage after bonding, without residual adhesive, and without damaging the electronic components.

[0003] Under certain conditions, the adhesive properties of some anti-sticking tapes are reduced to the point where the adherend can be easily detached. For example, the principle of easy-to-pull adhesive (also known as removable tape) is that the cohesive force of the tape is much greater than the adhesive force between the adhesive layer and the backing. When the tape is removed, it will not break during the stretching process, and the tape can be smoothly removed from the adhered object. UV anti-sticking tape (also known as UV anti-sticking tape) is made of a special glue that shows high adhesion in normal conditions, but the adhesion drops sharply after ultraviolet irradiation. Electrolytic tape needs to be attached to a conductive adhered object and achieves anti-sticking through the effect of current. The above anti-sticking tapes are not suitable for the transportation and processing of some high-precision parts due to the restrictions of anti-sticking conditions or actual production environment. Thermal anti-sticking tape achieves the purpose of anti-sticking by adding heat-expanding microspheres, which expand at high temperature and the diameter of the ball is greater than the coating thickness. At present, there are problems such as the viscosity of thermal anti-sticking tapes still being significantly retained after anti-sticking, and the outer wall of the microspheres is easily broken after expansion and adheres to the adhered object, resulting in residual glue, which greatly limits the actual application. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a heat-reducing pressure-sensitive adhesive tape and a preparation method thereof in view of the deficiencies in the above-mentioned prior art.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: in the first aspect of the present invention, a heat-reducing pressure-sensitive adhesive tape is provided, comprising a release layer, a heat-reducing layer and a substrate layer which are stacked in sequence, wherein the heat-reducing layer is obtained by coating a heat-reducing adhesive on the substrate layer and then curing the heat-reducing adhesive, wherein the heat-reducing adhesive comprises the following raw material components in parts by weight: 90 to 120 parts of an acrylate copolymer resin, 5 to 15 parts of a modified resin, 0.01 to 1 part of a curing agent, 2 to 10 parts of modified heat-expandable microspheres, and 20-60 parts of a solvent.

[0006] Preferably, the modified heat-expandable microspheres are heat-expandable microspheres whose outer shell is a thermoplastic polypropylene copolymer as base balls, and are obtained by modifying the surface of the base balls with tridecafluorooctyltrimethoxysilane.

[0007] Preferably, the particle size of the base ball is 10-20 μm, and the expansion temperature is 110-150°C.

[0008] Preferably, the modified thermal expansion microparticle is prepared by the following method:

[0009] Tridecafluorooctyltrimethoxysilane is uniformly sprayed on heat-expandable microspheres whose outer shell is thermoplastic polypropylene copolymer, kneaded and dispersed, and sealed under heating; the treated heat-expandable microspheres are cooled to room temperature and immersed in a potassium hydroxide aqueous solution, heated and stirred for reaction, and after the reaction is completed, the pH is adjusted to acidic, filtered, and the solid product is rinsed with pure water and dried to constant weight to obtain modified heat-expandable microspheres.

[0010] Preferably, the modified thermal expansion microparticle is prepared by the following method:

[0011] Take 100 parts by weight of heat-expandable microspheres with a particle size of 10 to 20 μm, an expansion temperature of 110 to 150° C., and an outer shell of a thermoplastic polypropylene copolymer, spray 0.5 to 1.3 parts by weight of tridecafluorooctyltrimethoxysilane evenly on the heat-expandable microspheres, knead and disperse, and seal and treat at 40° C. for 6 hours; after the treated heat-expandable microspheres are cooled to room temperature, they are immersed in a 0.5 mol / L potassium hydroxide aqueous solution, heated to 45° C., stirred and reacted for 2 hours, and after the reaction is completed, the reaction solution is adjusted to a pH value of 5.5-6.5 with an HCl aqueous solution, filtered, and the solid product is rinsed with pure water and dried to a constant weight to obtain modified heat-expandable microspheres.

[0012] Preferably, the acrylic ester copolymer resin is prepared by the following method:

[0013] Nitrogen is introduced into a reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile are added to the reaction container, and stirred at 70-80° C. for 6-24 hours under a nitrogen protective atmosphere. After the reaction is completed, the mixture is cooled to room temperature, and a diluting solvent is added to the product to obtain an acrylate copolymer resin with a solid content of 30-50%.

[0014] Preferably, the acrylic ester copolymer resin is prepared by the following method:

[0015] Nitrogen was introduced into the reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile were added to the reaction container, and the mixture was stirred and reacted at 75° C. for 12 hours under a nitrogen protective atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and a diluent solvent was added to the product to obtain an acrylate copolymer resin with a solid content of 40%.

[0016] Preferably, the modified resin is selected from one or more of rosin resin, terpene resin, and terpene phenol resin;

[0017] The curing agent is selected from one or more of isocyanate curing agents, epoxy curing agents, and pyridine curing agents;

[0018] The solvent is selected from one or more of ethyl acetate, toluene, butanone and isopropanol.

[0019] A second aspect of the present invention provides a method for preparing the heat-reducing pressure-sensitive adhesive tape as described above, comprising the following steps:

[0020] S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive;

[0021] S2. The heat-reducing adhesive is evenly coated on the surface of the substrate layer, pre-baked at 50-70°C for 2-6 minutes, and then baked at 80-120°C for 4-15 minutes to obtain a heat-reducing adhesive layer, and then a release layer is attached to the adhesive surface, and aged at 50-70°C for 1-6 days to obtain the heat-reducing adhesive pressure-sensitive tape.

[0022] Preferably, the method for preparing the heat-reducing pressure-sensitive adhesive tape comprises the following steps:

[0023] S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive;

[0024] S2, the heat-reducing adhesive is evenly coated on the surface of the substrate layer, pre-baked at 60°C for 3 minutes, and then baked at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm, and then a release layer is attached to the adhesive surface, and aged at 55°C for 3 days to obtain the heat-reducing adhesive pressure-sensitive tape;

[0025] The substrate layer is a PET film with a thickness of 50 μm, and the release layer is a silicon-coated release film with a thickness of 25 μm.

[0026] The beneficial effects of the present invention are:

[0027] The invention improves the compatibility and weather resistance of the modified heat-expandable microspheres in acrylic pressure-sensitive adhesives by specially modifying the modified heat-expandable microspheres (the surface modifier tridecafluorooctyl trimethoxysilane used in the modified heat-expandable microspheres has hydrophobicity and lipophilicity, and can improve the compatibility of the microspheres with the colloid; at the same time, tridecafluorooctyl can improve the chemical resistance and heat resistance of the heat-expandable microspheres, and can ensure that the microspheres are not prone to cracking and residual adhesive problems during the process of making and storing the adhesive tape and the actual use process), and are more easily dispersed into the colloid, thereby reducing the production process difficulties in the production of the adhesive tape; and by adding special functional monomers, the heat-expandable microspheres are easily dispersed into the colloid, and the surface modifier tridecafluorooctyl trimethoxysilane used in the modified heat-expandable microspheres has hydrophobicity and lipophilicity, and can improve the compatibility of the microspheres with the colloid. A kind of acrylate copolymer tree with excellent adhesion, lasting adhesion and good cohesion is synthesized in a targeted manner; the heat-reducing adhesive prepared by adding modified heat-expandable microspheres into the acrylate copolymer tree has excellent adhesion at room temperature, which is no less than that of normal tape bonding; and after the tape particles are expanded at a suitable temperature, controllable viscosity reduction or even loss of adhesion can be achieved, and no residual adhesive will be generated on the surface of the adhered object to pollute the product and cause secondary damage to the cleaning of the residual adhesive. The heat-reducing pressure-sensitive adhesive tape of the present invention can be well applied to the fields of MLCC, resistors, inductors, filters, and wafer semiconductors.

[0028] The heat-reduced adhesive tape provided by the present invention can be guided by actual product application requirements and the proportion of modified expanded microspheres can be controlled to adjust the viscosity after heat-reduction to 0-600 gf / inch, thereby expanding the application range of the market; there is no residual adhesive after tearing off, and no pollution is caused to the back sticker, so it has good market potential. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0030] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0031] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0032] The invention provides a heat-reducing viscosity pressure-sensitive adhesive tape, comprising a release layer, a heat-reducing viscosity layer and a substrate layer which are sequentially stacked, wherein the heat-reducing viscosity layer is obtained by coating a heat-reducing viscosity adhesive on the substrate layer and then curing the heat-reducing viscosity adhesive, and the heat-reducing viscosity adhesive comprises the following raw material components in parts by weight: 90-120 parts of an acrylate copolymer resin, 5-15 parts of a modified resin, 0.01-1 parts of a curing agent, 2-10 parts of modified heat-expandable microspheres and 20-60 parts of a solvent.

[0033] In a preferred embodiment, the modified heat-expandable microspheres are heat-expandable microspheres with a shell of thermoplastic polypropylene copolymer as base balls, and are obtained by modifying the surface of the base balls with tridecafluorooctyltrimethoxysilane.

[0034] In a preferred embodiment, the particle size of the base ball is 10-20 μm, and the expansion temperature is 110-150°C.

[0035] In a preferred embodiment, the modified thermal expansion microparticles are prepared by the following method:

[0036] Take 100 parts by weight of heat-expandable microspheres with a particle size of 10 to 20 μm, an expansion temperature of 110 to 150° C., and an outer shell of a thermoplastic polypropylene copolymer, spray 0.5 to 1.3 parts by weight of tridecafluorooctyltrimethoxysilane evenly on the heat-expandable microspheres, knead and disperse, and seal and treat at 40° C. for 6 hours; after the treated heat-expandable microspheres are cooled to room temperature, they are immersed in a 0.5 mol / L potassium hydroxide aqueous solution, heated to 45° C., stirred and reacted for 2 hours, and after the reaction is completed, the reaction solution is adjusted to pH = 5.5-6.5 with an HCl aqueous solution, filtered, and the solid product is rinsed with pure water and dried to constant weight to obtain modified heat-expandable microspheres.

[0037] In a preferred embodiment, the acrylate copolymer resin is prepared by the following method:

[0038] Nitrogen is introduced into a reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile are added to the reaction container, and stirred at 70-80° C. for 6-24 hours under a nitrogen protective atmosphere. After the reaction is completed, the mixture is cooled to room temperature, and a diluting solvent is added to the product to obtain an acrylate copolymer resin with a solid content of 30-50%.

[0039] In a preferred embodiment, the modified resin is selected from one or more of rosin resin, terpene resin, and terpene phenol resin.

[0040] In a preferred embodiment, the curing agent is selected from one or more of isocyanate curing agents, epoxy curing agents, and pyridine curing agents.

[0041] In a preferred embodiment, the solvent is selected from one or more of ethyl acetate, toluene, butanone, and isopropanol.

[0042] The present invention also provides a method for preparing the above heat-reducing pressure-sensitive adhesive tape, comprising the following steps:

[0043] S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive;

[0044] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer, pre-bake at 50-70°C for 2-6 minutes, and then bake at 80-120°C for 4-15 minutes to obtain a heat-reducing adhesive layer, and then attach a release layer to the adhesive surface, and mature at 50-70°C for 1-6 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0045] In a preferred embodiment, the method for preparing the heat-reducing pressure-sensitive adhesive tape comprises the following steps:

[0046] S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive;

[0047] S2, the heat-reducing adhesive is evenly coated on the surface of the substrate layer, pre-baked at 60°C for 3 minutes, and then baked at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm, and then a release layer is attached to the adhesive surface, and aged at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape;

[0048] The substrate layer is a PET film with a thickness of 50 μm, and the release layer is a silicon-coated release film with a thickness of 25 μm.

[0049] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept of the present invention to further illustrate the present invention.

[0050] 1. The modified thermal expansion microparticles are prepared in advance by the following method:

[0051] Take 100 parts by weight of heat-expandable microspheres with a particle size of 10 to 20 μm, an expansion temperature of 110 to 150° C., and an outer shell of a thermoplastic polypropylene copolymer (specifically, F-36D microspheres produced by Matsumoto Oil & Fats Pharmaceutical Co., Ltd. of Japan), spray 0.9 parts by weight of tridecafluorooctyltrimethoxysilane evenly on the heat-expandable microspheres, knead and disperse, and seal and treat at 40° C. for 6 hours; after the treated heat-expandable microspheres are cooled to room temperature, they are immersed in a 0.5 mol / L potassium hydroxide aqueous solution, heated to 45° C., stirred and reacted for 2 hours, and after the reaction is completed, the reaction solution is adjusted to pH=6 with an HCl aqueous solution, filtered, and the solid product is rinsed with pure water and dried to constant weight to obtain modified heat-expandable microspheres.

[0052] 2. Prepare the acrylic acid ester copolymer resin in advance by the following method:

[0053] Nitrogen was introduced into the reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile were added to the reaction container, and the mixture was stirred and reacted at 75° C. for 12 hours under a nitrogen protective atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and a diluent solvent was added to the product to obtain an acrylate copolymer resin with a solid content of 40%.

[0054] The modified thermal expansion micro- and acrylate copolymer resin prepared above was used in the following examples and comparative examples.

[0055] Example 1

[0056] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0057] S1, 100 parts by weight of acrylate copolymer resin, 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.), and 5 parts by weight of modified thermal expansion microspheres are added to 35.6 parts by weight of ethyl acetate, stirred and dispersed evenly, and then degassed statically to obtain a thermal viscosity-reducing adhesive;

[0058] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0059] Example 2

[0060] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0061] S1, 100 parts by weight of acrylate copolymer resin, 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.), and 7 parts by weight of modified thermally expandable microspheres are added to 35.6 parts by weight of ethyl acetate, stirred and dispersed evenly, and then degassed at rest to obtain a thermally deviscous adhesive;

[0062] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0063] Example 3

[0064] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0065] S1, 100 parts by weight of acrylate copolymer resin, 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.), and 2 parts by weight of modified thermal expansion microspheres are added to 35.6 parts by weight of ethyl acetate, stirred and dispersed evenly, and then degassed statically to obtain a thermal viscosity-reducing adhesive;

[0066] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0067] Comparative Example 1

[0068] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0069] S1, add 100 parts by weight of common glue PS-8281 (Shimei Chemical Industry Co., Ltd.), 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.), and 5 parts by weight of modified thermal expansion microspheres to 35.6 parts by weight of ethyl acetate, stir and disperse evenly, and then degas for static degassing to obtain a heat-reduced viscosity adhesive;

[0070] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0071] Comparative Example 2

[0072] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0073] S1, 100 parts by weight of acrylate copolymer resin, 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.), and 5 parts by weight of thermal expansion microspheres (specifically F-36D microspheres from Matsumoto Oil Pharmaceutical Co., Ltd. of Japan) are added to 35.6 parts by weight of ethyl acetate, stirred and dispersed evenly, and then degassed statically to obtain a thermal viscosity-reducing adhesive;

[0074] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0075] Comparative Example 3

[0076] A heat-reducing pressure-sensitive adhesive tape, the preparation method of which comprises the following steps:

[0077] S1, 100 parts by weight of acrylate copolymer resin, 16 parts by weight of KB120 resin (Guangzhou Kemao Chemical Co., Ltd., pre-treated with ethyl acetate solvent to a solid content of 50%, the same below), 0.8 parts by weight of a curing agent with an isocyanate functional group (specifically an aromatic polyisocyanate, selected from Shandong Yinglang Chemical Co., Ltd.), and 0.02 parts by weight of a curing agent with an epoxy functional group (specifically ETERAC EC-97 epoxy curing agent from Changxing Materials Industry Co., Ltd.) are added to 35.6 parts by weight of ethyl acetate, stirred and dispersed evenly, and then degassed statically to obtain a heat-reduced viscosity adhesive;

[0078] S2. Evenly apply the heat-reducing adhesive on the surface of the substrate layer (50 μm PET film), pre-bake at 60°C for 3 minutes, and then bake at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm. Then, a 25 μm thick silicon-coated release film is attached to the adhesive surface, and matured at 55°C for 3 days to obtain a heat-reducing adhesive pressure-sensitive tape.

[0079] The heat-detackifying pressure-sensitive tapes prepared in the embodiments and comparative examples were respectively tested for peel strength after conventional heat detackification at 110°C and 130°C after lamination to steel plates, initial adhesion of the tape after heat detackification, and holding power. The residual adhesive area ratio of the test specimens was observed and recorded: 0 (no residual adhesive), 0-5% (a small amount of residual adhesive), 5%-20% (more residual adhesive), and >20% (a large amount of residual adhesive).

[0080] Thickness test, refer to GB / T 7125-2014 Adhesive tape thickness test method;

[0081] For peel strength test, refer to GB / T 2792-2014 Test method for peel strength of adhesive tape;

[0082] Initial adhesion test, refer to GB / T31125-2014 Adhesive tape initial adhesion test method-ring method;

[0083] For holding force test, refer to GB / T4851-2014 test method for adhesive tape holding force;

[0084] The ratio of residual adhesive area is measured by the peeling force test to observe the ratio of residual adhesive area on the steel plate to the total bonding area.

[0085] The test results are shown in Table 1 below:

[0086] Table 1

[0087]

[0088] In the table, some results of Comparative Example 1 and Comparative Example 2 are range values. The reason is that a rough estimate is adopted to judge the residual glue degree by the percentage range of the residual glue area to the total area of ​​the steel plate through the peeling force test.

[0089] By comparing and analyzing Example 1 and Example 3, by reasonably adjusting the dosage ratio of the modified heat-expandable microspheres, the conventional performance of the tape does not change much, and will not affect the normal use of the tape. However, after thermal expansion and viscosity reduction at 110°C and 130°C, the peeling force and initial adhesion of the tape change significantly. The viscosity after thermal viscosity reduction can be adjusted by controlling the ratio of the modified expandable microspheres according to the actual product application requirements.

[0090] Comparative Example 1 shows that when ordinary conventional glue is selected as the original glue of the heat-reducing adhesive tape, the holding force in the conventional performance has shifted downward by 2mm. After the heat-reducing process, the actual peeling force test data is not stable. After the heat-reducing process of the steel plate, there is an obvious problem of residual glue. This is mainly because the Tg point of the glue is low, the colloid is soft, and the cohesion is poor. During the high-temperature heat-reducing process, as the microspheres expand, the glue layer is gradually destroyed, and residual glue is easily generated on the adhered object.

[0091] Comparative Example 2 shows that when the heat-expandable microspheres are directly used in the tape without modification, the mechanical properties of the conventional test are unchanged, but residual glue appears on the test steel plate. The main reason is that when the heat-expandable microspheres are not modified, their compatibility with the glue is poor, and stirring and dispersing is obviously difficult during the glue preparation process. During the tape test, the microspheres and the colloid may shift and fall off, resulting in a cohesive deviation of the overall adhesive layer, causing residual glue.

[0092] It can be seen from Comparative Example 3 that when the tape is directly coated with the synthetic acrylic copolymer adhesive without adding heat-expandable microspheres, the peeling force hardly changes after being subjected to high temperature, indicating that the simple pressure-sensitive tape has no viscosity-reducing effect.

[0093] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A heat-reducing pressure-sensitive adhesive tape, characterized in that: The invention comprises a release layer, a heat-reducing viscosity layer and a substrate layer which are stacked in sequence. The heat-reducing viscosity layer is obtained by coating a heat-reducing viscosity adhesive on the substrate layer and then curing the heat-reducing viscosity adhesive. The heat-reducing viscosity adhesive comprises the following raw material components in parts by weight: 90-120 parts of an acrylate copolymer resin, 5-15 parts of a modified resin, 0.01-1 parts of a curing agent, 2-10 parts of modified heat-expandable microspheres and 20-60 parts of a solvent.

2. The heat-reducing pressure-sensitive adhesive tape according to claim 1, characterized in that: The modified heat-expandable microspheres are obtained by using heat-expandable microspheres whose outer shell is a thermoplastic polypropylene copolymer as base balls and modifying the surface of the base balls with tridecafluorooctyltrimethoxysilane.

3. The heat-reducing pressure-sensitive adhesive tape according to claim 2, characterized in that: The particle size of the base ball is 10-20 μm, and the expansion temperature is 110-150°C.

4. The heat-reducing pressure-sensitive adhesive tape according to claim 2, characterized in that: The modified thermal expansion microparticles are prepared by the following method: Tridecafluorooctyltrimethoxysilane is uniformly sprayed on heat-expandable microspheres whose outer shell is thermoplastic polypropylene copolymer, kneaded and dispersed, and sealed under heating; the treated heat-expandable microspheres are cooled to room temperature and immersed in a potassium hydroxide aqueous solution, heated and stirred for reaction, and after the reaction is completed, the pH is adjusted to acidic, filtered, and the solid product is rinsed with pure water and dried to constant weight to obtain modified heat-expandable microspheres.

5. The heat-reducing pressure-sensitive adhesive tape according to claim 4, characterized in that: The modified thermal expansion microparticles are prepared by the following method: Take 100 parts by weight of heat-expandable microspheres with a particle size of 10 to 20 μm, an expansion temperature of 110 to 150° C., and an outer shell of a thermoplastic polypropylene copolymer, spray 0.5 to 1.3 parts by weight of tridecafluorooctyltrimethoxysilane evenly on the heat-expandable microspheres, knead and disperse, and seal and treat at 40° C. for 6 hours; after the treated heat-expandable microspheres are cooled to room temperature, they are immersed in a 0.5 mol / L potassium hydroxide aqueous solution, heated to 45° C., stirred and reacted for 2 hours, and after the reaction is completed, the reaction solution is adjusted to a pH value of 5.5-6.5 with an HCl aqueous solution, filtered, and the solid product is rinsed with pure water and dried to a constant weight to obtain modified heat-expandable microspheres.

6. The heat-reducing pressure-sensitive adhesive tape according to claim 1, characterized in that: The acrylic ester copolymer resin is prepared by the following method: Nitrogen is introduced into a reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile are added to the reaction container, and stirred at 70-80° C. for 6-24 hours under a nitrogen protective atmosphere. After the reaction is completed, the mixture is cooled to room temperature, and a diluting solvent is added to the product to obtain an acrylate copolymer resin with a solid content of 30-50%.

7. The heat-reducing pressure-sensitive adhesive tape according to claim 6, characterized in that: The acrylic ester copolymer resin is prepared by the following method: Nitrogen was introduced into the reaction container in advance to purge the air, and then 228 parts by weight of n-butyl acrylate, 41.5 parts by weight of methyl acrylate, 4 parts by weight of vinyl pyrrolidone, 5 parts by weight of 4-hydroxybutyl acrylate, 10.5 parts by weight of acrylic acid, 365 parts by weight of ethyl acetate, and 0.3 parts by weight of azobisisobutyronitrile were added to the reaction container, and the mixture was stirred and reacted at 75° C. for 12 hours under a nitrogen protective atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and a diluent solvent was added to the product to obtain an acrylate copolymer resin with a solid content of 40%.

8. The heat-reducing pressure-sensitive adhesive tape according to claim 1, characterized in that: The modified resin is selected from one or more of rosin resin, terpene resin, and terpene phenol resin; The curing agent is selected from one or more of isocyanate curing agents, epoxy curing agents, and pyridine curing agents; The solvent is selected from one or more of ethyl acetate, toluene, butanone and isopropanol.

9. A method for preparing a heat-reducing pressure-sensitive adhesive tape as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive; S2. The heat-reducing adhesive is evenly coated on the surface of the substrate layer, pre-baked at 50-70°C for 2-6 minutes, and then baked at 80-120°C for 4-15 minutes to obtain a heat-reducing adhesive layer, and then a release layer is attached to the adhesive surface, and aged at 50-70°C for 1-6 days to obtain the heat-reducing adhesive pressure-sensitive tape.

10. The method for preparing the heat-reducing pressure-sensitive adhesive tape according to claim 9, characterized in that: The following steps are involved: S1, adding acrylate copolymer resin, modified resin, curing agent, and modified heat-expandable microspheres into a solvent, stirring and dispersing them uniformly, and then degassing them statically to obtain a heat-reduced viscosity adhesive; S2, the heat-reducing adhesive is evenly coated on the surface of the substrate layer, pre-baked at 60°C for 3 minutes, and then baked at 100°C for 8 minutes to obtain a heat-reducing adhesive layer with a thickness of 50 μm, and then a release layer is attached to the adhesive surface, and aged at 55°C for 3 days to obtain the heat-reducing adhesive pressure-sensitive tape; The substrate layer is a PET film with a thickness of 50 μm, and the release layer is a silicon-coated release film with a thickness of 25 μm.

Images