High temperature resistant pressure sensitive adhesive, high temperature resistant PI protective tape and preparation method thereof

Abstract

The present application belongs to the technical field of adhesive materials, and the present application discloses a high temperature resistant pressure-sensitive adhesive, a high temperature resistant PI protective tape and a preparation method. The raw materials of the high temperature resistant pressure-sensitive adhesive in the present application include modified polydimethylsiloxane, methyl methacrylate, n-butyl acrylate, N-methoxymethyl acrylamide, an organic solvent, a curing agent and an initiator. The high temperature resistant PI protective tape in the present application includes a laminating adhesive layer, a primer layer, a coloring layer and a PI substrate layer connected in sequence from top to bottom; the laminating adhesive layer is formed by a high temperature resistant pressure-sensitive adhesive. The preparation method of the high temperature resistant PI protective tape in the present application includes the following steps: (1) preparing a PI substrate layer, a coloring layer, a primer layer and a laminating adhesive layer in sequence; (2) drying and aging to obtain a high temperature resistant PI protective tape. The high temperature resistant PI protective tape prepared in the present application has excellent high temperature resistance and weather resistance, and does not leave residual adhesive or transfer pollution in a high temperature use environment of 260°C.

Description

Technical Field

[0001] The present application relates to the technical field of adhesive materials, and in particular to a high temperature resistant pressure sensitive adhesive, a high temperature resistant PI protective tape and a preparation method thereof. Background Art

[0002] PCB printed circuit boards and other circuit boards are classified into three major categories according to the number of layers: single-sided boards, double-sided boards and multi-layer circuit boards. Among them, multi-layer boards refer to printed boards with more than three layers of conductive graphic layers and insulating materials in between, and the conductive graphics in between are interconnected as required. During the PCB pressing process, PI protective tape is required to protect the surface of the pressed substrate and prevent glue from overflowing. PI protective tape is also called polyimide tape, commonly known as gold finger tape. It is based on polyimide film and uses pressure-sensitive adhesive. It has high and low temperature resistance, acid and alkali resistance, solvent resistance, electrical insulation (H grade), radiation protection and other properties. It is mainly used in the electronics industry. The adhesive or pressure-sensitive adhesive used in the existing PI protective tape is not resistant to high temperatures of 260°C, is prone to yellowing, has poor pollution resistance, and is prone to watermarks and other fog pollution, which will have an adverse effect on the appearance and performance of the pressed PCB board. Summary of the invention

[0003] In order to solve at least one of the above technical problems, a high-temperature resistant PI protective tape specially used for pressing plates is developed, which has excellent heat and weather resistance, can be used at a pressing temperature of 260°C without fogging or residual adhesive. The application provides a high-temperature resistant pressure-sensitive adhesive, a high-temperature resistant PI protective tape and a preparation method.

[0004] In the first aspect, the present application provides a high temperature resistant pressure-sensitive adhesive, comprising the following raw materials in parts by weight: 1-5 parts of modified polydimethylsiloxane, 5-9 parts of methyl methacrylate, 22-35 parts of n-butyl acrylate, 3-8 parts of N-methoxymethylacrylamide, 45-60 parts of organic solvent, 1.5-6 parts of curing agent, and 0.1-1 part of initiator.

[0005] By adopting the above technical scheme, the high temperature resistant pressure sensitive adhesive in this application is an adhesive prepared by cross-linking reaction with methyl methacrylate as hard monomer, n-butyl acrylate as soft monomer, and N-methoxymethyl acrylamide as functional monomer. -CONHOCH3 group and -COOH group are introduced into the molecular structure of the acrylic ester high temperature resistant adhesive system. Cross-linking reaction can occur in the subsequent drying and aging process of the prepared PI protective tape, thereby increasing the degree of cross-linking, forming a dense network structure, and improving the transparency, thereby achieving the improvement of the high temperature resistance of the pressure sensitive adhesive and good storage stability at room temperature. The above three monomers are selected for combination, and the glass transition temperature (Tg) of the prepared polymer is controlled at 0-15°C, and the rheological modulus is about 105Pa at 23°C, so that the prepared pressure sensitive adhesive has good high temperature resistance, and at the same time improves the initial adhesion performance of the pressure sensitive adhesive, and then the PI protective tape prepared using the pressure sensitive adhesive is not easy to decompose in a high temperature environment and when the bonding strength changes little, resulting in fogging or yellowing.

[0006] Optionally, the modified polydimethylsiloxane is selected from BYK371.

[0007] By adopting the above technical scheme, modified polydimethylsiloxane is introduced into the polymerization system. The modified polydimethylsiloxane is selected from BYK371, which is a polyester-modified polydimethylsiloxane containing acrylic functional groups, and is a polyester-modified organosiloxane containing double bonds. It has good compatibility with the acrylic ester adhesive system. The modified polydimethylsiloxane as an organosiloxane can significantly increase the hydrophobic properties and heat resistance of the high temperature resistant pressure-sensitive adhesive, while reducing the surface tension of the high temperature resistant pressure-sensitive adhesive, showing better leveling and bonding properties.

[0008] Optionally, the curing agent is a two-component curing agent, and the curing agent includes an isocyanate curing agent and an epoxy curing agent.

[0009] Preferably, the curing agent comprises an isocyanate curing agent and an epoxy curing agent in a weight ratio of 0.8-1.8:2.5-8.3.

[0010] Preferably, the isocyanate curing agent is selected from at least one of hexamethylene diisocyanate and isophorone diisocyanate.

[0011] Preferably, the epoxy curing agent is selected from dicyandiamide.

[0012] By adopting the above-mentioned technical scheme, the present application uses isocyanate curing agent and epoxy curing agent in combination in the acrylic adhesive system, and at the same time limits the usage ratio of isocyanate curing agent and epoxy curing agent, so as to achieve precise control of the cross-linking degree of the prepared high temperature resistant pressure-sensitive adhesive, and then control the initial adhesion performance and lasting adhesion performance of the adhesive, avoiding atomization and residual adhesive phenomenon during use.

[0013] Preferably, the raw materials of the high temperature resistant pressure sensitive adhesive further include 3 parts by weight of perfluorooctyl methacrylate.

[0014] By adopting the above technical solution, the introduction of organic fluorine monomers into the acrylic ester polymerization system of the high temperature resistant pressure sensitive adhesive is beneficial to improve the water resistance and weather resistance of the pressure sensitive adhesive. The introduction of CF bonds into the cross-linking system greatly improves the cohesive energy of the high temperature resistant pressure sensitive adhesive. In addition, the organic fluorine monomer has excellent compatibility and adaptability with the polyester modified polydimethylsiloxane containing acrylic functional groups as an organic silicon monomer.

[0015] Optionally, the organic solvent is selected from one or more of ethyl acetate, propylene glycol methyl ether acetate, isopropanol, toluene and xylene.

[0016] Preferably, the organic solvent comprises ethyl acetate and xylene in a weight ratio of 70-92:15-30.

[0017] Preferably, the organic solvent comprises ethyl acetate and xylene in a weight ratio of 78:22.

[0018] By adopting the above technical solution, xylene has a large chain transfer constant, and adding a certain proportion of xylene to the ethyl acetate solvent as a mixed polymerization solvent can be used to regulate the molecular weight of the acrylate copolymer and the viscosity of the pressure-sensitive adhesive. The addition of high-boiling point xylene makes the solvent volatilize at a moderate rate during the tape drying process, and can also reduce the generation of bubbles on the adhesive surface of the protective tape. The increase in the amount of xylene reduces the weight average molecular weight of the acrylate copolymer. After the molecular weight is adjusted, the fluidity of the pressure-sensitive adhesive increases, which is suitable for the coating of the tape.

[0019] In the second aspect, the present application provides a method for preparing the above-mentioned high temperature resistant pressure-sensitive adhesive, comprising the following steps: adding raw materials except the initiator to a reaction vessel, passing a protective gas, maintaining the temperature at 70-90°C and continuously stirring at a rate of 180-220rpm, adding 50wt% of the initiator to the reaction vessel, the addition time is controlled at 0.5-1h, and the temperature is kept warm for 1-2h after the addition is completed; continuing to add 25wt% of the initiator, the addition time is controlled at 0.2-0.5h, and the temperature is kept warm for 1-2h after the addition is completed; continuing to add the remaining initiator, the addition time is controlled at 0.2-0.5h, and the temperature is kept warm for 1.5-3h after the addition is completed; cooling to obtain the high temperature resistant pressure-sensitive adhesive.

[0020] Preferably, the preparation method of the high temperature resistant pressure-sensitive adhesive is as follows: adding other raw materials except the initiator to a reaction container, passing nitrogen, maintaining the temperature at 85°C and continuously stirring at a rate of 185rpm, dripping 50wt% of the initiator into the reaction container, the dripping time is controlled at 0.6h, and the temperature is kept warm for 1.2h after the dripping is completed; continuing to drip 25wt% of the initiator, the dripping time is controlled at 0.3h, and the temperature is kept warm for 1.2h after the dripping is completed; continuing to drip the remaining initiator, the dripping time is controlled at 0.3h, and the temperature is kept warm for 2h after the dripping is completed; cooling to obtain the high temperature resistant pressure-sensitive adhesive.

[0021] In the third aspect, the present application provides a high temperature resistant PI protective tape prepared from the above-mentioned high temperature resistant pressure-sensitive adhesive, comprising a pressing adhesive layer, a primer layer, a coloring layer and a PI substrate layer connected in sequence from top to bottom, wherein the pressing adhesive layer is formed by the high temperature resistant pressure-sensitive adhesive.

[0022] In a fourth aspect, the present application provides a method for preparing the above-mentioned high temperature resistant PI protective tape, characterized in that it comprises the following steps:

[0023] S1, performing corona treatment on a single surface of a polyimide substrate to obtain a PI substrate layer;

[0024] S2, coating a colorant on the surface of the PI substrate layer obtained in step S1 to obtain a colored layer;

[0025] S3, coating the surface of the colored layer obtained in step S2 with a polyurethane resin to obtain a primer layer;

[0026] S4, coating the surface of the base coating obtained in step S3 with a high temperature resistant pressure sensitive adhesive, drying, and curing to obtain the high temperature resistant PI protective tape.

[0027] Optionally, in the step S1, the surface tension value of the corona-treated PI substrate layer is 46-60 dyn / cm; and the surface tension value of the colored layer obtained in the step S2 is 50-60 dyn / cm.

[0028] Optionally, in step S4, the drying process is performed at 80-130° C. for 2-5 min, and the aging process is performed at 30-50° C. for 1-5 days.

[0029] Preferably, in step S4, the drying process is performed at 85° C. for 3 minutes, and the aging process is performed at 35° C. for 3 days.

[0030] In summary, the present invention includes at least one of the following beneficial technical effects:

[0031] 1. The high-temperature resistant PI protective tape made of high-temperature resistant pressure-sensitive adhesive in the present application has excellent high-temperature resistance and weather resistance. During the PCB board lamination process, it can still effectively prevent glue overflow during the lamination process under high temperature conditions of 260°C. There is no residual glue, no yellowing, and no transfer pollution under the high temperature use environment of 260°C. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] The present application designs a high temperature resistant pressure-sensitive adhesive, which comprises the following raw materials in parts by weight: 1-5 parts of modified polydimethylsiloxane, 5-9 parts of methyl methacrylate, 22-35 parts of n-butyl acrylate, 3-8 parts of N-methoxymethyl acrylamide, 45-60 parts of organic solvent, 1.5-6 parts of curing agent, and 0.1-1 part of initiator.

[0034] The modified polydimethylsiloxane is selected from BYK371.

[0035] The curing agent includes an isocyanate curing agent and an epoxy curing agent.

[0036] The isocyanate curing agent is selected from at least one of hexamethylene diisocyanate and isophorone diisocyanate.

[0037] The epoxy curing agent is selected from dicyandiamide.

[0038] The high temperature resistant pressure-sensitive adhesive of the present application is prepared by the following method: adding raw materials except the initiator into a reaction container, passing protective gas, maintaining the temperature at 70-90°C and continuously stirring at a rate of 180-220rpm, dripping 50wt% of the initiator into the reaction container, the dripping time is controlled to be 0.5-1h, and the temperature is kept for 1-2h after the dripping is completed; continuing to drip 25wt% of the initiator, the dripping time is controlled to be 0.2-0.5h, and the temperature is kept for 1-2h after the dripping is completed; continuing to drip the remaining initiator, the dripping time is controlled to be 0.2-0.5h, and the temperature is kept for 1.5-3h after the dripping is completed; cooling to obtain the high temperature resistant pressure-sensitive adhesive.

[0039] The present application also designs a high temperature resistant PI protective tape prepared from the above-mentioned high temperature resistant pressure-sensitive adhesive, comprising a pressing adhesive layer, a primer layer, a coloring layer and a PI substrate layer connected in sequence from top to bottom, wherein the pressing adhesive layer is formed by the high temperature resistant pressure-sensitive adhesive.

[0040] The high temperature resistant PI protective tape of the present application is prepared by the following method:

[0041] S1, performing corona treatment on a single surface of a polyimide substrate to obtain a PI substrate layer;

[0042] S2, coating a colorant on the surface of the PI substrate layer obtained in step S1 to obtain a colored layer;

[0043] S3, coating the surface of the colored layer obtained in step S2 with a polyurethane resin to obtain a primer layer;

[0044] S4, coating the surface of the base coating obtained in step S3 with a high temperature resistant pressure sensitive adhesive, drying, and curing to obtain the high temperature resistant PI protective tape.

[0045] The technical problem solved by this application is that the adhesive used in the existing PI protective tape has poor high temperature resistance of 260°C, is prone to yellowing, has poor pollution resistance, and is prone to produce mist pollution such as watermarks, which will have an adverse effect on the appearance and performance of the pressed PCB board. This application selects suitable polymer monomers, adds modified polydimethylsiloxane and organic fluorine monomers, and uses a two-component curing agent and a two-component organic solvent to prepare a high-temperature resistant pressure-sensitive adhesive with good heat resistance and weather resistance. The high-temperature resistant PI protective tape prepared using the high-temperature resistant pressure-sensitive adhesive has excellent high-temperature resistance and weather resistance. During the PCB board pressing process, it can still effectively prevent the pressure-sensitive adhesive from overflowing under high temperature conditions of 260°C. There is no residual glue, no yellowing, and no transfer of pollution under the high temperature of 260°C.

[0046] The raw materials used in the examples of this application are all commercially available from the following sources:

[0047] Methyl methacrylate, n-butyl acrylate, isobutyl methacrylate, Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0048] N-methoxymethylacrylamide, Hubei Xinkang Pharmaceutical Chemical Co., Ltd.;

[0049] BYK371, BYK Chemical, Germany;

[0050] Hexamethylene diisocyanate, Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0051] Dicyandiamide, Shanghai Yuanye Biotechnology Co., Ltd.;

[0052] Benzoyl peroxide, Nanjing Chemical Reagent Co., Ltd.;

[0053] 2-Methylimidazole, Wuhan Profo Biotechnology Co., Ltd.;

[0054] Perfluorooctyl methacrylate, Zhongshan Dixin Chemical Co., Ltd.

[0055] Preparation Example 1-5

[0056] Preparation Examples 1-5 are high temperature resistant pressure sensitive adhesives prepared with different raw material ratios. The specific raw material ratios are shown in Table 1.

[0057] Table 1

[0058]

[0059] The organic solvent used in Preparation Example 1-5 is a mixed solvent of ethyl acetate and xylene in a weight ratio of 78:22.

[0060] The curing agent used in Preparation Example 1-5 is a mixture of an isocyanate curing agent and an epoxy curing agent in a weight ratio of 1.2:5, wherein the isocyanate curing agent is hexamethylene diisocyanate and the epoxy curing agent is dicyandiamide.

[0061] The modified polydimethylsiloxane used in Preparation Examples 1-5 is BYK371.

[0062] The initiator used in Preparation Example 1-5 is benzoyl peroxide.

[0063] The preparation process of Preparation Example 1-5 is:

[0064] The other raw materials except the initiator are added into the reaction container, nitrogen is passed through, the temperature is maintained at 85°C and stirring is continued at a rate of 185 rpm, 50 wt% of the initiator is added dropwise to the reaction container, the adding time is controlled within 0.6 h, and the temperature is kept warm for 1.2 h after the adding is completed; 25 wt% of the initiator is continued to be added dropwise, the adding time is controlled within 0.3 h, and the temperature is kept warm for 1.2 h after the adding is completed; the remaining initiator is continued to be added dropwise, the adding time is controlled within 0.3 h, and the temperature is kept warm for 2 h after the adding is completed; cooling is performed to obtain the high temperature resistant pressure-sensitive adhesive.

[0065] Preparation Example 6-7

[0066] Preparation Example 6 is based on Preparation Example 2, with the difference being that the curing agent used in Preparation Example 6 is a mixture of an isocyanate curing agent and an epoxy curing agent in a weight ratio of 0.8:8.3, wherein the isocyanate curing agent is hexamethylene diisocyanate and the epoxy curing agent is dicyandiamide.

[0067] Preparation Example 7 is based on Preparation Example 2, with the difference being that the curing agent used in Preparation Example 7 is a mixture of an isocyanate curing agent and an epoxy curing agent in a weight ratio of 1.8:2.5, wherein the isocyanate curing agent is hexamethylene diisocyanate and the epoxy curing agent is dicyandiamide.

[0068] Preparation Example 8-9

[0069] Preparation Example 8 is based on Preparation Example 2, except that the curing agent used in Preparation Example 8 is an isocyanate curing agent, and the isocyanate curing agent is hexamethylene diisocyanate.

[0070] Preparation Example 9 is based on Preparation Example 2, with the difference that the curing agent used in Preparation Example 9 is a mixture of an isocyanate curing agent and an imidazole curing agent in a weight ratio of 1.2:5, wherein the isocyanate curing agent is hexamethylene diisocyanate and the imidazole curing agent is 2-methylimidazole.

[0071] Preparation Example 10

[0072] Preparation Example 10 is based on Preparation Example 2, except that 3 parts by weight of perfluorooctyl methacrylate are further added to the raw materials of Preparation Example 10.

[0073] Preparation Example 11-12

[0074] Preparation Example 11 is based on Preparation Example 2, except that the organic solvent used in Preparation Example 11 is a mixed solvent of ethyl acetate and xylene in a weight ratio of 70:30.

[0075] Preparation Example 12 is based on Preparation Example 2, except that the organic solvent used in Preparation Example 12 is a mixed solvent of ethyl acetate and xylene in a weight ratio of 92:15.

[0076] Preparation Examples 13-14

[0077] Preparation Example 13 is based on Preparation Example 2, except that the organic solvent used in Preparation Example 13 is ethyl acetate.

[0078] Preparation Example 14 is based on Preparation Example 2, except that the organic solvent used in Preparation Example 14 is a mixed solvent of ethyl acetate and propylene glycol methyl ether acetate in a weight ratio of 78:22.

[0079] Preparation Comparative Examples 1-3

[0080] Preparation Comparative Example 1 is based on Preparation Example 2, except that methyl methacrylate is replaced by isobutyl methacrylate in Preparation Comparative Example 1.

[0081] Preparation Comparative Example 2 is based on Preparation Example 2, except that the amount of N-methoxymethyl acrylamide used in Preparation Comparative Example 2 is changed to 11 parts by weight.

[0082] Preparation Example 3 is based on Preparation Example 2, except that the amount of modified polydimethylsiloxane used in Preparation Example 3 is changed to 8 parts by weight.

[0083] Examples 1-14

[0084] Examples 1-14 are high temperature resistant PI protective tapes made using the high temperature resistant pressure sensitive adhesives prepared in Preparation Examples 1-14. The high temperature resistant pressure sensitive adhesives used in Examples 1-14 correspond to Preparation Examples 1-14 in sequence.

[0085] Comparative Examples 1-3

[0086] Comparative Examples 1-3 are high temperature resistant PI protective tapes prepared using the high temperature resistant pressure sensitive adhesives prepared in Comparative Examples 1-3. The high temperature resistant pressure sensitive adhesives used in Comparative Examples 1-3 correspond to the preparation examples 1-3 in sequence.

[0087] The corresponding preparation examples in Examples 1-14 and Comparative Examples 1-3 are shown in Table 2.

[0088] Table 2

[0089]

[0090] The preparation process of Examples 1-14 and Comparative Examples 1-3 is as follows:

[0091] S1. Performing corona treatment on one surface of a polyimide substrate film to obtain a PI substrate layer, wherein the surface tension of the corona-treated PI substrate layer is about 50 dyn / cm, and the thickness of the polyimide substrate film is about 0.5 mm.

[0092] S2, coating the surface of the PI substrate layer obtained in step S1 with a colorant to obtain a colored layer; wherein the colorant is formulated as 80 parts by weight of urethane resin, 15 parts by weight of yellow iron oxide, 3 parts by weight of light stabilizer, 1 part by weight of hexamethylene diisocyanate, and 2.5 parts by weight of dicyandiamide. The coating amount of the colorant is about 40 g / m 2 The thickness of the coloring layer is about 50um, and the surface tension value of the obtained coloring layer is about 55dyn / cm.

[0093] S3, coating the surface of the colored layer obtained in step S2 with polyurethane resin to obtain a primer layer; the coating amount of the polyurethane resin is about 60g / m 2 , the base coating thickness is about 100um.

[0094] S4, coating the surface of the primer layer obtained in step S3 with a high temperature resistant pressure sensitive adhesive to obtain a pressure-sensitive adhesive layer, wherein the coating amount of the high temperature resistant pressure sensitive adhesive is about 30 g / m 2 The thickness of the pressed adhesive layer is about 30 um. Then, the laminate is dried at 85°C for 3 minutes and aged at 35°C for 3 days to obtain the high temperature resistant PI protective tape.

[0095] Performance Testing

[0096] 1. The performance of the high temperature resistant PI protective tapes prepared in Examples 1-14 and Comparative Examples 1-3 was tested with reference to the standard GB / T2410-2008 "Testing and determination of light transmittance and haze of transparent plastics", and the instrument used was BYK4775 enhanced projection haze meter.

[0097] 2. Peel strength test: The peel strength of the high temperature resistant PI protective tapes prepared in Examples 1-14 and Comparative Examples 1-3 at 260° C. was measured with reference to the standard GB / T2792-1998.

[0098] 3. High temperature resistance test: Prepare the sample according to the reference standard GB / T2792-1998, put the bonded PCB board and PI protective tape into a 260℃ oven, take them out after a certain period of time (80min, 60min or 90min in Table 3 is the above-mentioned "certain period of time"), and observe the residual glue.

[0099] The performance test results are shown in Table 3.

[0100] Table 3

[0101]

[0102]

[0103] By analyzing the data in Table 3, the PI protective tape prepared in Example 10 has the best performance in terms of permeability, peel strength and high temperature resistance. Therefore, in the present application, methyl methacrylate, n-butyl acrylate and N-methoxymethyl acrylamide are used as basic polymerization monomers, and modified polydimethylsiloxane and perfluorooctyl methacrylate are added at the same time. A two-component curing agent of isocyanate curing agent and epoxy curing agent in a specific proportion is selected as the curing agent, and a two-component solvent of ethyl acetate and xylene in a specific proportion is selected as the organic solvent to achieve the purpose of controlling the molecular weight and holding force of the high temperature resistant pressure-sensitive adhesive, so that the prepared adhesive has good high temperature resistance, good rheology and good weather resistance, so that the prepared PI protective tape is suitable for use in the PCB lamination process to play a better protective role.

[0104] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high temperature resistant pressure sensitive adhesive, characterized in that: The method comprises the following raw materials in parts by weight: 1-5 parts of modified polydimethylsiloxane, 5-9 parts of methyl methacrylate, 22-35 parts of n-butyl acrylate, 3-8 parts of N-methoxymethyl acrylamide, 45-60 parts of organic solvent, 1.5-6 parts of curing agent, and 0.1-1 part of initiator; The curing agent comprises an isocyanate curing agent and dicyandiamide in a weight ratio of 0.8-1.8:2.5-8.3; The isocyanate curing agent is selected from at least one of hexamethylene diisocyanate and isophorone diisocyanate.

2. The high temperature resistant pressure sensitive adhesive according to claim 1, characterized in that: The modified polydimethylsiloxane is selected from BYK371.

3. The high temperature resistant pressure sensitive adhesive according to claim 1, characterized in that: The raw materials of the high temperature resistant pressure sensitive adhesive also include 3 parts by weight of perfluorooctyl methacrylate.

4. The high temperature resistant pressure sensitive adhesive according to claim 1, characterized in that: The organic solvent comprises ethyl acetate and xylene in a weight ratio of 70-92:15-30.

5. A method for preparing the high temperature resistant pressure sensitive adhesive according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: adding raw materials except the initiator into a reaction container, passing protective gas, maintaining the temperature at 70-90°C and continuously stirring at a rate of 180-220rpm, dripping 50wt% of the initiator into the reaction container, controlling the dripping time to be 0.5-1h, and keeping the temperature for 1-2h after the dripping is completed; continuing to drip 25wt% of the initiator, controlling the dripping time to be 0.2-0.5h, and keeping the temperature for 1-2h after the dripping is completed; continuing to drip the remaining initiator, controlling the dripping time to be 0.2-0.5h, and keeping the temperature for 1.5-3h after the dripping is completed; The mixture is cooled to obtain the high temperature resistant pressure sensitive adhesive.

6. A high temperature resistant PI protective tape made from the high temperature resistant pressure sensitive adhesive according to any one of claims 1 to 4, characterized in that: It includes a laminating adhesive layer, a primer layer, a coloring layer and a PI substrate layer which are sequentially connected from top to bottom; The pressed adhesive layer is formed by high temperature resistant pressure sensitive adhesive.

7. A method for preparing the high temperature resistant PI protective tape according to claim 6, characterized in that: The following steps are involved: S1, performing corona treatment on a single surface of a polyimide substrate to obtain a PI substrate layer; S2, coating a colorant on the surface of the PI substrate layer obtained in step S1 to obtain a colored layer; S3, coating the surface of the colored layer obtained in step S2 with a polyurethane resin to obtain a primer layer; S4, coating the surface of the base coating obtained in step S3 with a high temperature resistant pressure sensitive adhesive, drying, and curing to obtain the high temperature resistant PI protective tape.

8. The method for preparing the high temperature resistant PI protective tape according to claim 7, characterized in that: The surface tension value of the PI substrate layer subjected to the corona treatment in step S1 is 46-60 dyn / cm; the surface tension value of the coloring layer obtained in step S2 is 50-60 dyn / cm.

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