High temperature easy-to-peel heat-reducing viscosity pressure-sensitive adhesive and preparation method thereof

Abstract

The present invention provides a high-temperature easy-to-peel heat-reducing adhesive protective film, comprising a substrate layer, a heat-reducing adhesive layer and a release layer; the heat-reducing adhesive layer comprises the following components calculated by added mass: 60-80 parts of polyacrylate prepolymer; 0.1-0.5 parts of curing agent; 0.1-0.5 parts of catalyst; 1-3 parts of expanded microspheres; 2-10 parts of tackifying resin; 10-20 parts of organic solvent; the present invention also provides a method for preparing a high-temperature easy-to-peel heat-reducing adhesive protective film. The high-temperature easy-to-peel heat-reducing adhesive protective film provided by the present invention overcomes the defects of residual glue, slow viscosity reduction speed, low efficiency, etc. existing in the prior art, improves the viscosity reduction speed of the protective film, thereby improving the efficiency, and can meet the use requirements of temporary fixation of electronic components, surface processing of semiconductor wafers and other fields.

Description

Technical Field

[0001] The invention relates to the technical field of protective films, and in particular to a high-temperature easy-to-peel heat-reducing viscosity-reducing pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] With the continuous advancement of science and technology, the intelligence level of electronic equipment is increasing day by day. An important means to improve the competitiveness of enterprises is to maintain the stability and sustainability of production processes. In order to ensure the continuity and stability of the production process of high-end electronic products, enterprises usually take various protective measures in the process to ensure it.

[0003] At present, there are two main types of protection methods for electronic components: one is low-viscosity pressure-sensitive protective film, and the other is anti-viscosity protective film. For electronic components with rough surfaces, low-viscosity pressure-sensitive protective film has poor adhesion, and slippage may occur during the manufacturing process, resulting in poor protection effect, so there are some defects. Anti-viscosity protective film is divided into thermal anti-viscosity and UV anti-viscosity protective film. UV anti-viscosity film does not perform well at high temperatures. High-temperature heating will cause tiny molecules in the film to remain on the surface of the object being adhered, making it difficult to clean. In addition, UV anti-viscosity film cannot completely lose adhesion after UV irradiation, so it has certain limitations in application.

[0004] The thermal anti-adhesive protective film can be firmly bonded to the object at room temperature, and its adhesion is no different from that of ordinary tape. After processing, it only needs to be heated to a certain temperature, and the adhesion of the protective film itself will decrease. It can be easily peeled off at a constant temperature without damaging the processed object. It helps to realize automation in the electronic component production process, save manpower, and improve product yield. It is often used in electronic component production processes such as wafer cutting, temporary fixation, and coating masking.

[0005] The Chinese invention patent (CN 117801730A) provides a reversible heat-reducing pressure-sensitive adhesive and a preparation method thereof. Long alkyl polyacrylate has high-temperature melting characteristics. When the temperature rises above the melting point, the long alkyl polyacrylate undergoes a solid-liquid transition, which enhances the fluidity of the pressure-sensitive adhesive and reduces the peel strength of the pressure-sensitive adhesive. However, since the solid-liquid transition of the heat-reducing pressure-sensitive adhesive is reversible, the bonding strength increases again after the temperature drops to room temperature, making it impossible to carry out the subsequent steps at room temperature. For another example, the Chinese invention patent (CN 115926691A) provides a reactive heat-reducing protective film and a preparation method thereof. The initiator is decomposed at high temperature to further cross-link the epoxy-containing unsaturated acrylate adhesive in the adhesive layer, and the viscosity of the adhesive layer is greatly reduced, making it easy to peel off, and there is no residual adhesive on the surface of the adhered object after peeling. However, this method takes a long time to reduce the viscosity, and the peeling force is greatly reduced after 10 minutes of heat treatment, and the efficiency is low. Therefore, the present invention aims to develop a high-temperature easy-to-peel thermal viscosity-reducing protective film, which can be easily peeled off at a constant temperature after high-temperature viscosity reduction, and has the characteristics of high initial viscosity, short viscosity reduction time, high efficiency and no pollution after peeling, so as to solve the problems raised in the above background technology. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, an object of the present invention is to provide a high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, characterized in that: the thermal viscosity-reducing pressure-sensitive adhesive protective film comprises from the outside to the inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The heat-reducing pressure-sensitive adhesive layer comprises the following components calculated by added mass: Polyacrylate prepolymer 60-80 parts; Curing agent 0.1-0.5 parts; Catalyst 0.1-0.5 parts; 1-3 parts of expanded microspheres; 2-10 parts of tackifying resin; 10-20 parts of organic solvent.

[0007] The polyacrylate prepolymer comprises the following components calculated by added mass: Acrylate soft monomer 60-80 parts; 10-20 parts of acrylic acid hard monomer; 5-10 parts of functional monomer; Initiator 0.1-3 parts; 100-180 parts of organic solvent; The weight average molecular weight of the polyacrylate prepolymer is 200000-800000 g / mol, the glass transition temperature is -40°C--50°C, and the hydroxyl content is 0.5 wt%-1.5 wt%.

[0008] The acrylic ester soft monomer is one or more combinations of ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and lauryl methacrylate; the acrylic ester hard monomer is one or more combinations of vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, and methyl acrylate; the functional monomer is one or more combinations of acrylic acid, methacrylic acid, hydroxyethyl acrylate, methacrylamide, and trimethylolpropane triacrylate; the initiator is a peroxide initiator, including di-tert-butyl peroxide, tert-butyl perbenzoate, and dibenzoyl peroxide; or the initiator is an azo initiator, including one of azobisisobutyronitrile, azobisisoheptonitrile, and dimethyl azobisisobutyrate; and the organic solvent is ethyl acetate.

[0009] The curing agent is an isocyanate curing agent, and adopts 1,6-hexanediisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), 1,6-hexanediisocyanate (IPDI), epoxy resin curing agent, including one of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate.

[0010] The catalyst is one of platinum catalyst, dibutyltin dilaurate, stannous octoate, tetrabutyltin, triethylenediamine and titanium acetylacetonate.

[0011] The expandable microspheres are thermoplastic hollow polymer microspheres with a shell-core structure, with a diameter of 10 to 50 μm, a density of 400 to 1200 kg / m3, an expansion temperature range of 80°C to 180°C, and no shrinkage after expansion; the shell is a thermoplastic acrylic polymer and the core is a low-boiling hydrocarbon compound.

[0012] The tackifying resin is one or more combinations of pentaerythritol ester rosin ester, hydrogenated rosin octyl ester, acrylic acid modified rosin resin, disproportionated rosin glycerol ester, α-pinene resin, terpene phenol resin, C5 petroleum resin, and C9 petroleum resin.

[0013] The organic solvent is ethyl acetate.

[0014] A method for preparing a high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film comprises the following steps: Step 1: Weigh 2 / 3 of the acrylate soft monomer, 2 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an organic solvent to obtain a mixed monomer A; mix the remaining 1 / 3 of the acrylate soft monomer, 1 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an initiator to obtain a mixed monomer B; Step 2: Add the mixed monomer A into the reactor at one time, heat it in a water bath to 60-80°C, introduce nitrogen to expel the air, and keep the polymerization reaction in an oxygen-free environment; add the mixed monomer B into the funnel, and uniformly add it dropwise to the mixed monomer A, and stir it uniformly at a speed of 200r / min with a polytetrafluoroethylene stirring paddle to make it fully react, and control the dropping time of the mixed monomer B to be 2-3h; Step 3: After the mixed monomers are added dropwise, the temperature of the reactor is maintained at 60-80°C, the reaction is continued for 4-6 hours, and the polymer is cooled to room temperature to obtain a polyacrylate prepolymer; Step 4: Weigh the polyacrylate prepolymer, curing agent, catalyst, expanded microspheres, tackifying resin and solvent of step 103, mix and stir evenly to obtain a mixed adhesive, apply a heat-reducing pressure-sensitive adhesive layer on the corona surface of the PET film, and pull the substrate at a speed of 5-10 mm / s; bake the coated heat-reducing pressure-sensitive adhesive at 60-80°C for 10-20 minutes, compound a release film on the obtained heat-reducing pressure-sensitive adhesive layer, put it in a 50°C oven for aging for 1-3 days, and finally obtain a protective film.

[0015] The high-temperature easy-to-peel thermal viscosity-reducing protective film provided by the present invention overcomes the defects of residual glue, slow viscosity-reducing speed, low efficiency and the like in the prior art. The polyacrylate prepolymer polymerized from acrylate soft monomers and acrylic acid hard monomers is used to increase the viscosity-reducing speed of the protective film, thereby increasing the efficiency. The protective film can meet the use requirements in the fields of temporary fixation of electronic components, surface processing of semiconductor wafers, and the like.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, some embodiments are described in detail below. The specific implementation of the present invention is given in detail by the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 This is a schematic diagram of the structure of a high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film of the present invention: Among them, 1 is substrate layer, 2 is heat-reducing pressure-sensitive adhesive layer, and 3 is release layer.

[0018] Figure 2 This is the infrared spectrum of the polyacrylate prepolymer prepared in Example 3. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings, and the aforementioned and other purposes, features, aspects and advantages of the present invention will become more obvious, so that those skilled in the art can implement it with reference to the text of the specification. In the accompanying drawings, for the sake of clarity, the shapes and sizes can be enlarged, and the same reference numerals will be used in all figures to indicate the same or similar parts. In the following description, words such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, lower, etc. are based on the orientation or position relationship shown in the accompanying drawings. In particular, "height" is equivalent to the size from top to bottom, "width" is equivalent to the size from left to right, and "depth" is equivalent to the size from front to back. These relative terms are for the convenience of explanation and are generally not intended to require specific orientation. Terms related to attachment, connection, etc. (for example, "connection" and "attachment") refer to the relationship between these structures directly or indirectly fixed or attached to each other through intermediate structures, and movable or rigid attachment or relationship, unless otherwise explicitly stated.

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0021] like Figure 1 As shown, a high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprises from the outside to the inside: a substrate layer 1, a heat-reducing pressure-sensitive adhesive layer 2 and a release layer 3; the heat-reducing pressure-sensitive adhesive layer is characterized in that it comprises the following components calculated by added mass: Polyacrylate prepolymer 60-80 parts; Curing agent 0.1-0.5 parts; Catalyst 0.1-0.5 parts; 1-3 parts of expanded microspheres; 2-10 parts of tackifying resin; 10-20 parts of organic solvent; The high-temperature easy-to-peel heat-reducing adhesive protective film of the present invention has relatively high viscosity initially, can be completely debonded after being subjected to a certain high temperature, and has a fast debonding speed and high efficiency.

[0022] In some embodiments, the polyacrylate prepolymer comprises the following components calculated by added mass: 60-80 parts of acrylic soft monomer; 10-20 parts of acrylic acid hard monomer; 5-10 parts of functional monomer; Initiator 0.1-3 parts; 100-180 parts of organic solvent In some embodiments, the acrylic ester soft monomer is an acrylic ester monomer with a glass transition temperature (Tg) of -20°C to -70°C, including one or more combinations of ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and lauryl methacrylate, which can impart certain flexibility and ductility to the polyacrylate prepolymer in the polymerization reaction.

[0023] In some embodiments, the acrylic ester hard monomer is an acrylic ester monomer with a glass transition temperature (Tg) of 0°C to 180°C, including one or more combinations of vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, and methyl acrylate, which imparts a certain hardness and tensile strength to the polyacrylate prepolymer during the polymerization reaction.

[0024] In some embodiments, the functional monomer is acrylic acid, methacrylic acid, hydroxyethyl acrylate, methacrylamide, trimethylolpropane triacrylate, 2-phenoxyethyl acrylate and dodecyl acrylate. In order to increase the crosslinking density of the pressure-sensitive adhesive and thus improve its stability, preferably, the functional monomer is an organic compound containing two or more active groups.

[0025] In some embodiments, the initiator is a peroxide initiator, including di-tert-butyl peroxide, tert-butyl perbenzoate, dibenzoyl peroxide; or an azo initiator, including one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate. In order to improve the stability of the pressure-sensitive adhesive and avoid thermal decomposition and side reactions, preferably, the initiator is a low-temperature polymerization initiator.

[0026] In some embodiments, the curing agent is an isocyanate curing agent, including 1,6-hexanediisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), and 1,6-hexanediisocyanate (IPDI); an epoxy resin curing agent, including one of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate.

[0027] In some embodiments, the catalyst is one of a platinum catalyst, dibutyltin dilaurate, stannous octoate, tetrabutyltin, triethylenediamine, and titanium acetylacetonate.

[0028] In some embodiments, the expanded microspheres are thermoplastic hollow polymer microspheres with a core-shell structure, a diameter of 10 to 50 μm, and a density of 400 to 1200 kg / m 3 , the expansion temperature range is 80°C to 180°C, and there is no contraction after expansion; preferably, the shell is a thermoplastic acrylic polymer and the core is a low-boiling hydrocarbon compound.

[0029] In some embodiments, the tackifying resin is one or more combinations of pentaerythritol ester rosin ester, hydrogenated rosin octyl ester, acrylic modified rosin resin, disproportionated rosin glycerol ester, α-pinene resin, terpene phenol resin, C5 petroleum resin, and C9 petroleum resin.

[0030] The present invention also relates to a method for preparing a high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, comprising the following steps: Step 1: Weigh 2 / 3 of the acrylate soft monomer, 2 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and a solvent to obtain a mixed monomer A; mix the remaining 1 / 3 of the acrylate soft monomer, 1 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an initiator to obtain a mixed monomer B; Step 2: Add the mixed monomer A into the reactor at one time, heat it in a water bath to 60-80°C, introduce nitrogen to expel the air, and keep the polymerization reaction in an oxygen-free environment; add the mixed monomer B into the funnel, and uniformly add it dropwise to the mixed monomer A, and stir it uniformly at a speed of 200r / min with a polytetrafluoroethylene stirring paddle to make it fully react, and control the dropping time of the mixed monomer B to be 2-3h; Step 3: After the mixed monomers are added dropwise, the temperature of the reactor is maintained at 60-80°C and the reaction is continued for 4-6 hours, and then the polymer is cooled to room temperature to obtain a polyacrylate prepolymer; Step 4: Weigh the polyacrylate prepolymer, curing agent, catalyst, expanded microspheres, tackifying resin and solvent of step 103, mix and stir evenly to obtain a mixed adhesive, apply a heat-reducing pressure-sensitive adhesive layer on the corona surface of the PET film, and pull the substrate at a speed of 5-10 mm / s; bake the coated heat-reducing pressure-sensitive adhesive at 60-80°C for 10-20 minutes, composite a release film on the obtained heat-reducing pressure-sensitive adhesive layer, put it in a 50°C oven for aging for 2-3 days, and finally obtain a protective film.

[0031] Embodiment 1: A high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; 0.2 parts of toluene diisocyanate (TDI) as curing agent; 0.3 parts of dibutyltin dilaurate as catalyst; 3 parts of expanded microspheres; 5 parts of tackifying resin: acrylic acid modified rosin resin; 10 parts of organic solvent: ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method comprises the following steps: Step 1: Weigh 2 / 3 of the acrylate soft monomer, 2 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an organic solvent to obtain a mixed monomer A; mix the remaining 1 / 3 of the acrylate soft monomer, 1 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an initiator to obtain a mixed monomer B; Step 2: Add the mixed monomer A into the reactor at one time, heat it in a water bath to 65°C, introduce nitrogen to expel the air, and keep the polymerization reaction in an oxygen-free environment; add the mixed monomer B into the funnel, and uniformly add it dropwise to the mixed monomer A, and stir it uniformly at a speed of 200r / min with a polytetrafluoroethylene stirring paddle to make it fully react, and control the dropping time of the mixed monomer B to be 3h; Step 3: After the mixed monomers are added dropwise, the temperature of the reactor is maintained at 65°C and the reaction is continued for 4-6 hours, and then the polymer is cooled to room temperature to obtain a polyacrylate prepolymer; Step 4: Weigh 60 parts of the polyacrylate prepolymer of step 3, 0.2 parts of the curing agent, 0.3 parts of the catalyst, 3 parts of the expanded microspheres, 5 parts of the tackifying resin and 10 parts of the organic solvent, mix and stir evenly to obtain a mixed adhesive, apply a heat-reducing pressure-sensitive adhesive layer on the corona surface of the PET film, and pull the substrate at a speed of 5 mm / s; bake the coated heat-reducing pressure-sensitive adhesive at 60°C for 15 minutes, composite a release film on the obtained heat-reducing pressure-sensitive adhesive layer, put it in a 50°C oven for aging for 2 days, and finally obtain a protective film.

[0032] Embodiment 2: A high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 3 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0033] Embodiment 3: A high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 1 part of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0034] Embodiment 4: A high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 5 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0035] Figure 2 This is the infrared spectrum of the polyacrylate prepolymer prepared in Example 4. As can be seen from the figure, the wave number is 3000cm -1 It is the asymmetric stretching vibration of -CH3 and -CH2-, 2900cm -1 is the asymmetric stretching vibration of -CH2-, 1750cm -1 It is the stretching vibration absorption peak of the ester bond -C=O, which is relatively strong, 1500-1600cm -1 is the bending vibration of the -C=C- of the benzene ring, 1450 cm -1 At the same time, it is the bending vibration absorption peak of -CH2-, 1170 cm -1 、1250cm -1 It is the asymmetric stretching vibration of -COC-. 1620-1680cm -1 There is no stretching vibration of olefin -C=C-, indicating that the monomers have undergone copolymerization and the reaction is complete.

[0036] Embodiment 5: A high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, the heat-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 3 parts of expanded microspheres; tackifying resin: 10 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0037] Comparative Example 1: A high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, the thermal viscosity-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 3 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 5 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0038] Comparative Example 2: A high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, the thermal viscosity-reducing pressure-sensitive adhesive protective film comprising from outside to inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 3 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0039] Comparative Example 3: A high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, the thermal viscosity-reducing pressure-sensitive adhesive protective film comprising, from outside to inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 3 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0040] Comparative Example 4: A high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, the thermal viscosity-reducing pressure-sensitive adhesive protective film comprising, from outside to inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 5 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate hard monomer: 5 parts of methyl methacrylate, 5 parts of acrylamide; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0041] Comparative Example 5: A high-temperature easy-to-peel thermal viscosity-reducing pressure-sensitive adhesive protective film, the thermal viscosity-reducing pressure-sensitive adhesive protective film comprising, from outside to inside: a substrate layer, a thermal viscosity-reducing pressure-sensitive adhesive layer and a release layer; The thickness of the heat-reduced pressure-sensitive adhesive layer is 30 μm, and it includes the following components according to the added mass: 60 parts of polyacrylate prepolymer; curing agent: 0.2 parts of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; catalyst: 0.3 parts of dibutyltin dilaurate; 5 parts of expanded microspheres; tackifying resin: 5 parts of acrylic acid modified rosin resin; organic solvent: 10 parts of ethyl acetate; Polyacrylate prepolymer includes the following components calculated by added mass: Acrylate soft monomer: 50 parts of ethyl acrylate, 20 parts of 2-ethylhexyl acrylate; functional monomer: 2 parts of hydroxyethyl acrylate, 3 parts of 2-phenoxyethyl acrylate; initiator: 1 part of dimethyl azobisisobutyrate; organic solvent: 150 parts of ethyl acetate; The preparation method is the same as that of Example 1.

[0042] The test method of the high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film of the present invention is as follows: Peel strength test: Tested in accordance with the national standard GB / T 2792-2014 "Test method for peel strength of adhesive tape"; Viscosity reduction test: The protective film is attached to a glass plate and placed in a water bath / heating platform at a set temperature. The time required for the protective film to completely fall off is recorded to evaluate its viscosity reduction performance at high temperatures. Adhesion test: Tested in accordance with the national standard GB / T 4851-2014 "Test method for adhesion of adhesive tapes"; Initial adhesion test: Tested in accordance with the national standard GB / T 4852-2002 "Pressure-sensitive adhesive tape initial adhesion test method (rolling ball method)"; Residual adhesive test: stick the protective film on the glass plate and observe whether there is any adhesive residue on the glass surface when peeling off the protective film after heating treatment; The following Table 1 lists the test data of the products of different embodiments and comparative examples.

[0043]

[0044] The above is a preferred embodiment of the present invention. The high-temperature easily peelable pressure-sensitive adhesive protective film is obtained by the same or similar steps as the above-mentioned embodiments of the present invention. Comparative Examples 4 and 5 only use acrylate soft monomers or acrylate hard monomers for the polyacrylate prepolymer. The resulting protective film performance is different from that of Examples 1-5 and Comparative Examples 1-3 in terms of initial adhesion, viscosity reduction time, residual adhesive, etc.

[0045] 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 methods. 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 the specific details and the embodiments shown here.

Claims

1. A high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, characterized in that: The heat-reducing pressure-sensitive adhesive protective film comprises, from outside to inside: a substrate layer, a heat-reducing pressure-sensitive adhesive layer and a release layer; The heat-reducing pressure-sensitive adhesive layer comprises the following components calculated by added mass: Polyacrylate prepolymer 60-80 parts; Curing agent 0.1-0.5 parts; Catalyst 0.1-0.5 parts; 1-3 parts of expanded microspheres; 2-10 parts of tackifying resin; 10-20 parts of organic solvent.

2. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The polyacrylate prepolymer comprises the following components calculated by added mass: Acrylate soft monomer 60-80 parts; 10-20 parts of acrylic acid hard monomer; 5-10 parts of functional monomer; Initiator 0.1-3 parts; 100-180 parts of organic solvent; The weight average molecular weight of the polyacrylate prepolymer is 200000-800000 g / mol, the glass transition temperature is -40°C--50°C, and the hydroxyl content is 0.5 wt%-1.5 wt%.

3. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 2, characterized in that: The acrylic ester soft monomer is one or more combinations of ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and lauryl methacrylate; the acrylic ester hard monomer is one or more combinations of vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, and methyl acrylate; the functional monomer is one or more combinations of acrylic acid, methacrylic acid, hydroxyethyl acrylate, methacrylamide, and trimethylolpropane triacrylate; the initiator is a peroxide initiator, including di-tert-butyl peroxide, tert-butyl perbenzoate, and dibenzoyl peroxide; or the initiator is an azo initiator, including one of azobisisobutyronitrile, azobisisoheptonitrile, and dimethyl azobisisobutyrate; and the organic solvent is ethyl acetate.

4. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The curing agent is an isocyanate curing agent, and adopts 1,6-hexanediisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), 1,6-hexanediisocyanate (IPDI), epoxy resin curing agent, including one of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate.

5. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The catalyst is one of platinum catalyst, dibutyltin dilaurate, stannous octoate, tetrabutyltin, triethylenediamine and titanium acetylacetonate.

6. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The expanded microspheres are thermoplastic hollow polymer microspheres with a core-shell structure, a diameter of 10 to 50 μm, and a density of 400 to 1200 kg / m 3 The expansion temperature range is 80°C to 180°C, and there is no contraction after expansion; the shell is a thermoplastic acrylic polymer, and the core is a low-boiling hydrocarbon compound.

7. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The tackifying resin is one or more combinations of pentaerythritol ester rosin ester, hydrogenated rosin octyl ester, acrylic acid modified rosin resin, disproportionated rosin glycerol ester, α-pinene resin, terpene phenol resin, C5 petroleum resin, and C9 petroleum resin.

8. The high temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film according to claim 1, characterized in that: The organic solvent is ethyl acetate.

9. A method for preparing a high-temperature easy-to-peel heat-reducing pressure-sensitive adhesive protective film, comprising the following steps: Step 1: Weigh 2 / 3 of the acrylate soft monomer, 2 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an organic solvent to obtain a mixed monomer A; mix the remaining 1 / 3 of the acrylate soft monomer, 1 / 3 of the acrylate hard monomer, 1 / 2 of the functional monomer and an initiator to obtain a mixed monomer B; Step 2: Add the mixed monomer A into the reactor at one time, heat it in a water bath to 60-80°C, introduce nitrogen to expel the air, and keep the polymerization reaction in an oxygen-free environment; add the mixed monomer B into the funnel, and uniformly add it dropwise to the mixed monomer A, and stir it uniformly at a speed of 200r / min with a polytetrafluoroethylene stirring paddle to make it fully react, and control the dropping time of the mixed monomer B to be 2-3h; Step 3: After the mixed monomers are added dropwise, the temperature of the reactor is maintained at 60-80°C, the reaction is continued for 4-6 hours, and the polymer is cooled to room temperature to obtain a polyacrylate prepolymer; Step 4: Weigh the polyacrylate prepolymer, curing agent, catalyst, expanded microspheres, tackifying resin and solvent of step 103, mix and stir evenly to obtain a mixed adhesive, apply a heat-reducing pressure-sensitive adhesive layer on the corona surface of the PET film, and pull the substrate at a speed of 5-10 mm / s; bake the coated heat-reducing pressure-sensitive adhesive at 60-80°C for 10-20 minutes, compound a release film on the obtained heat-reducing pressure-sensitive adhesive layer, put it in a 50°C oven for aging for 1-3 days, and finally obtain a protective film.

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