A high temperature resistant, low viscosity and no residual adhesive protective film and preparation method thereof

Abstract

The invention relates to the technical field of protective films, and in particular to a high-temperature resistant, low-viscosity, non-residual adhesive protective film and a preparation method thereof. In order to improve the non-residual adhesive performance of the protective film, the invention uses 4-carboxylphenylboronic acid pinacol ester and bis(4-aminophenoxy)dimethylsilane as raw materials, and prepares a borosilicate intermediate containing free amino groups by controlling the reaction conditions and the change of the addition amount. The boron element and the silicon element contained in the intermediate both have good flame retardant properties, can effectively improve the flame retardant properties of the protective film, and improve the safety factor in the processing process. In addition, due to the introduction of the boron element and the silicon element, an O-B-O-segment and an O-Si-O-segment are introduced into the adhesive, and both have high bond energy, can effectively improve the high-temperature stability of the adhesive, so that the adhesive still has excellent performance at high temperatures, and can also effectively improve the cohesion of the adhesive, avoiding the residual adhesive phenomenon in the process of removing the protective film.

Description

Technical Field

[0001] The invention relates to the technical field of protective films, and in particular to a high-temperature resistant, low-viscosity, and non-residue adhesive protective film and a preparation method thereof. Background Art

[0002] Pressure-sensitive adhesive protective film is mainly used to protect the surface of components. During the component processing, in order to prevent damage to the components caused by factors such as transfer and transportation and collision and scratches during processing, a pressure-sensitive adhesive protective film is often applied to the surface of the component to protect the surface of the component, thereby reducing the occurrence of defects such as scratches; and with the completion of the processing, this type of pressure-sensitive adhesive protective film will be removed from the surface of the component again to ensure the normal use of the component; however, due to its own properties, pressure-sensitive adhesive sometimes remains on the surface of the protective film after the protective film is removed, which has a serious impact on the use of the component. Summary of the invention

[0003] The object of the present invention is to provide a high temperature resistant, low viscosity and non-residue adhesive protective film and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0005] S1. Preparation of borosilicate modified acrylate;

[0006] S11. Disperse 4-carboxyphenylboronic acid pinacol ester in toluene, protect under nitrogen atmosphere, and ultrasonically disperse for 15-40 minutes, then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 2-4 hours. After the dropwise addition is completed, heat to 85-95° C., stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0007] S12. Disperse melamine in DMAc, place in an ice-water bath until the temperature is constant, and then slowly dropwise add the melamine into a DMAc solution containing 1,6-hexamethylene diisocyanate, maintaining the temperature of the reaction system at 75-80°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85-90°C, and the reaction is continued with stirring for 0.5-2h. After cooling to room temperature, dibutyltin dilaurate and hydroxypropyl acrylate are added, the temperature is raised to 70-75°C, the reaction is continued for 1-3h, and the excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0008] S13. The isocyanate-modified acrylate intermediate was dispersed in pure DMAc, ultrasonically dispersed for 20-45 min, and protected under nitrogen atmosphere;

[0009] The borosilicate intermediate is dispersed in toluene, heated to 45-75°C, stirred and dispersed for 45-60 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition is completed, the temperature is raised to 110-112°C, and the temperature is kept to react for 1-1.5 hours, and then the temperature is raised to 115-118°C, and the reaction is stirred for 1-1.5 hours, and then the excess solvent is removed by rotary evaporation to obtain borosilicate-modified acrylate;

[0010] S2. Preparation of low residual viscosity modified adhesive;

[0011] Butyl acrylate, borosilicate modified acrylate and isooctyl acrylate are mixed, acetone is added, and the mixture is mixed for 5-10 minutes, and the temperature is raised to 75-80°C. Cumene hydroperoxide is added thereto slowly and uniformly within 1 hour. After the addition is completed, the mixture is stirred and reacted for 1-2 hours, and an antioxidant and a cross-linking agent are added. The mixture is mixed for 5-10 minutes, and acetone is added to obtain a low residual viscosity modified adhesive having a solid content of 20-30%.

[0012] S3. The inner surface of the base film is subjected to corona treatment, and a low residual adhesive modified adhesive is coated on the inner surface of the base film. The temperature is raised to 80-85°C, and after drying and curing for 8-15 minutes, a release film is coated on the adhesive surface, and the film is rolled up to obtain a high temperature resistant, low viscosity, and non-residual adhesive protective film.

[0013] Furthermore, in step S11, the mass ratio of the 4-carboxyphenylboronic acid pinacol ester to bis(4-aminophenoxy)dimethylsilane is (0.8-1):1.

[0014] Furthermore, in step S12, the mass ratio of melamine, hexamethylene diisocyanate, and dibutyl tin dilaurate is 1:(3.5-4):(0.02-0.03).

[0015] Furthermore, in step S12, the mass ratio of melamine to hydroxypropyl acrylate is 1:(1.8-2.1).

[0016] Furthermore, in step S13, the mass ratio of the isocyanate-modified acrylate intermediate to the borosilicate intermediate is 1:(0.4-0.6).

[0017] Furthermore, in step S2, the low residual viscosity modified adhesive is composed of 3-5 parts of butyl acrylate, 3-8 parts of borosilicate modified acrylate, 25-30 parts of isooctyl acrylate, 0.05-0.08 parts of isopropylbenzene hydroperoxide, 0.1-0.3 parts of antioxidant and 0.2-0.4 parts of cross-linking agent.

[0018] Furthermore, in step S2, the antioxidant is any one of hydroquinone and antioxidant TH-1790; and the cross-linking agent is isophorone diisocyanate.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] In order to improve the non-residue adhesive performance of the protective film, the present invention prepares and adds a component of borosilicate modified acrylate in the pressure-sensitive adhesive. The present invention uses 4-carboxylphenylboronic acid pinacol ester and bis(4-aminophenoxy)dimethylsilane as raw materials, and prepares a borosilicate intermediate containing free amino groups by controlling the reaction conditions and the change of the addition amount. The boron element and the silicon element contained in the intermediate have good flame retardant properties, which can effectively improve the flame retardant properties of the protective film and improve the safety factor in the processing process. In addition, due to the introduction of the boron element and the silicon element, an -OBO- segment and an -O-Si-O- segment are introduced into the adhesive, both of which have high bond energy, which can effectively improve the high-temperature stability of the adhesive, so that the adhesive still has excellent performance at high temperatures, and can also effectively improve the cohesion of the adhesive, avoiding the residual adhesive phenomenon in the process of removing the protective film.

[0021] At the same time, among the raw materials used in the present invention, 4-carboxyphenylboronic acid pinacol ester and bis(4-aminophenoxy)dimethylsilane both contain a large number of benzene ring structures. When borosilicate-modified acrylate is cross-linked with monomers such as butyl acrylate and isooctyl acrylate, these benzene ring structures, due to their own rigidity, will reduce the molecular chain dispersion of the adhesive, thereby reducing the bonding force of the adhesive, achieving a low-viscosity technical effect, and avoiding damage to electronic components caused by excessively high viscosity during peeling. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0024] S1. Preparation of borosilicate modified acrylate;

[0025] S11. Disperse 0.8 parts of 4-carboxyphenylboronic acid pinacol ester in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 minutes, and then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 3 hours. After the addition is completed, heat to 95°C, stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0026] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 1.8 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, and the reaction is continued for 2 hours. The excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0027] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0028] 0.4 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0029] S2. Preparation of low residual viscosity modified adhesive;

[0030] 4 parts of butyl acrylate, 3 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0031] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0032] Example 2. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0033] Compared with Example 1, this example increases the amount of borosilicate-modified acrylate added in step S2;

[0034] S1. Preparation of borosilicate modified acrylate;

[0035] S11. Disperse 0.8 parts of 4-carboxyphenylboronic acid pinacol ester in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 minutes, and then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 3 hours. After the addition is completed, heat to 95°C, stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0036] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 1.8 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, and the reaction is continued for 2 hours. The excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0037] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0038] 0.4 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0039] S2. Preparation of low residual viscosity modified adhesive;

[0040] 4 parts of butyl acrylate, 8 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0041] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0042] Example 3. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0043] Compared with Example 2, this example increases the amount of 4-carboxyphenylboronic acid pinacol ester added in step S11;

[0044] S1. Preparation of borosilicate modified acrylate;

[0045] S11. Disperse 1 part of 4-carboxyphenylboronic acid pinacol ester in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 min, and then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 3 h. After the addition is completed, heat to 95 ° C, stir and react for 2-6 h, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0046] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 1.8 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, and the reaction is continued for 2 hours. The excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0047] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0048] 0.4 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0049] S2. Preparation of low residual viscosity modified adhesive;

[0050] 4 parts of butyl acrylate, 8 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0051] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0052] Example 4. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0053] Compared with Example 2, this example increases the amount of hydroxypropyl acrylate added in step S12;

[0054] S1. Preparation of borosilicate modified acrylate;

[0055] S11. Disperse 0.8 parts of 4-carboxyphenylboronic acid pinacol ester in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 minutes, and then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 3 hours. After the addition is completed, heat to 95°C, stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0056] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 2.1 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, the reaction is continued for 2 hours, and the excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0057] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0058] 0.4 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0059] S2. Preparation of low residual viscosity modified adhesive;

[0060] 4 parts of butyl acrylate, 8 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0061] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0062] Example 5. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0063] Compared with Example 2, this example increases the amount of borosilicate intermediate added in step S13;

[0064] S1. Preparation of borosilicate modified acrylate;

[0065] S11. Disperse 0.8 parts of 4-carboxyphenylboronic acid pinacol ester in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 minutes, and then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 3 hours. After the addition is completed, heat to 95°C, stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0066] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 1.8 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, and the reaction is continued for 2 hours. The excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0067] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0068] 0.6 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0069] S2. Preparation of low residual viscosity modified adhesive;

[0070] 4 parts of butyl acrylate, 8 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0071] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0072] Comparative Example 1. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0073] Compared with Example 2, this comparative example does not add borosilicate-modified acrylate;

[0074] S1. Preparation of low residual viscosity modified adhesive;

[0075] 4 parts of butyl acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%;

[0076] S2. The low residual viscosity modified adhesive is coated on the surface of the base film, the temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the surface of the adhesive and rolled up to obtain a high temperature resistant, low viscosity and no residual adhesive protective film.

[0077] Comparative Example 2. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, comprising the following steps:

[0078] Compared with Example 2, this comparative example did not use 4-carboxyphenylboronic acid pinacol ester, but only used an equal amount of benzoic acid as a substitute;

[0079] S1. Preparation of borosilicate modified acrylate;

[0080] S11. Disperse 0.4 parts of benzoic acid in toluene by weight, protect under nitrogen atmosphere, ultrasonically disperse for 30 minutes, and then slowly add it dropwise to bis(4-aminophenoxy)dimethylsilane within 3 hours. After the addition is completed, heat to 95°C, stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate;

[0081] S12. Disperse 1 part of melamine in DMAc by weight, and after ice-water bath to constant temperature, slowly add it dropwise to DMAc solution containing 3.5 parts of 1,6-hexamethylene diisocyanate, and maintain the temperature of the reaction system at 75°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85°C, and the reaction is continued with stirring for 1 hour. After cooling to room temperature, 0.02 parts of dibutyltin dilaurate and 1.8 parts of hydroxypropyl acrylate are added, the temperature is raised to 75°C, and the reaction is continued for 2 hours. The excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate;

[0082] S13. By weight, 1 part of the isocyanate-modified acrylate intermediate was dispersed into pure DMAc, ultrasonically dispersed for 30 min, and protected by a nitrogen atmosphere;

[0083] 0.4 parts of borosilicate intermediate was dispersed in toluene, heated to 62°C, stirred and dispersed for 50 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition was completed, the temperature was raised to 112°C, kept for reaction for 1 hour, then raised to 118°C, stirred and reacted for 1 hour, and then the excess solvent was removed by rotary evaporation to obtain borosilicate-modified acrylate.

[0084] S2. Preparation of low residual viscosity modified adhesive;

[0085] 4 parts of butyl acrylate, 8 parts of borosilicate modified acrylate and 25 parts of isooctyl acrylate were mixed by weight, acetone was added, and the mixture was mixed for 5 minutes, and the temperature was raised to 75°C. 0.06 parts of cumene hydroperoxide were slowly added dropwise at a uniform speed within 1 hour. After the addition was completed, the mixture was stirred and reacted for 1.5 hours, and 0.1 parts of hydroquinone and 0.3 parts of isophorone diisocyanate were added. The mixture was mixed for 5 minutes, and acetone was added to obtain a low residual viscosity modified adhesive with a solid content of 25%.

[0086] S3. The inner surface of the base film is subjected to corona treatment, and a low residual viscosity modified adhesive is coated on the inner surface of the base film. The temperature is raised to 85°C, and after drying and curing for 12 minutes, a release film is coated on the adhesive surface and rolled up to obtain a high temperature resistant, low viscosity and non-residual adhesive protective film.

[0087] Testing: The protective films prepared in Examples 1-5 and Comparative Examples 1-2 were uniformly prepared as protective films with an adhesive layer thickness of 30 μm and a PI base film thickness of 25 μm, and performance tests were performed on them;

[0088] The 180°C peel strength test was conducted according to GB / T 2792-2014; the adhesion test was conducted according to GB / T 4851-2014;

[0089] The protective films prepared in Examples 1-5 and Comparative Examples 1-2 were attached to the surface of a stainless steel plate, placed in an environment with an ambient humidity of 90% and an ambient temperature of 50°C, aged for 12 hours, and then torn off to detect residual adhesive.

[0090] According to UL-94, the flame retardant performance grade of the protective films prepared in Examples 1-5 and Comparative Examples 1-2 was tested, and the test results are shown in the following table;

[0091]

[0092] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film, characterized in that: The following steps are involved: S1. Preparation of borosilicate modified acrylate; S11. Disperse 4-carboxyphenylboronic acid pinacol ester in toluene, protect under nitrogen atmosphere, and ultrasonically disperse for 15-40 minutes, then slowly dropwise add it to bis(4-aminophenoxy)dimethylsilane within 2-4 hours. After the dropwise addition is completed, heat to 85-95° C., stir and react for 2-6 hours, and then remove excess solvent by rotary evaporation to obtain a borosilicate intermediate; S12. Disperse melamine in DMAc, place in an ice-water bath until the temperature is constant, and then slowly dropwise add the melamine into a DMAc solution containing 1,6-hexamethylene diisocyanate, maintaining the temperature of the reaction system at 75-80°C during the dropwise addition. After the dropwise addition is completed, the temperature is raised to 85-90°C, and the reaction is continued with stirring for 0.5-2h. After cooling to room temperature, dibutyltin dilaurate and hydroxypropyl acrylate are added, the temperature is raised to 70-75°C, the reaction is continued for 1-3h, and the excess solvent is removed by rotary evaporation to obtain an isocyanate-modified acrylate intermediate; S13. The isocyanate-modified acrylate intermediate was dispersed in pure DMAc, ultrasonically dispersed for 20-45 min, and protected under nitrogen atmosphere; The borosilicate intermediate is dispersed in toluene, heated to 45-75°C, stirred and dispersed for 45-60 minutes, and then added dropwise to DMAc dispersed with isocyanate-modified acrylate intermediate. After the addition is completed, the temperature is raised to 110-112°C, and the temperature is kept to react for 1-1.5 hours, and then the temperature is raised to 115-118°C, and the reaction is stirred for 1-1.5 hours, and then the excess solvent is removed by rotary evaporation to obtain borosilicate-modified acrylate; S2. Preparation of low residual viscosity modified adhesive; Butyl acrylate, borosilicate modified acrylate and isooctyl acrylate are mixed, acetone is added, and the mixture is mixed for 5-10 minutes, and the temperature is raised to 75-80°C. Cumene hydroperoxide is added thereto slowly and uniformly within 1 hour. After the addition is completed, the mixture is stirred and reacted for 1-2 hours, and an antioxidant and a cross-linking agent are added. The mixture is mixed for 5-10 minutes, and acetone is added to obtain a low residual viscosity modified adhesive having a solid content of 20-30%. S3. The inner surface of the base film is subjected to corona treatment, and a low residual adhesive modified adhesive is coated on the inner surface of the base film. The temperature is raised to 80-85°C, and after drying and curing for 8-15 minutes, a release film is coated on the adhesive surface, and the film is rolled up to obtain a high temperature resistant, low viscosity, and non-residual adhesive protective film.

2. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S11, the mass ratio of the 4-carboxyphenylboronic acid pinacol ester to bis(4-aminophenoxy)dimethylsilane is (0.8-1):

1.

3. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S12, the mass ratio of melamine, hexamethylene diisocyanate and dibutyl tin dilaurate is 1:(3.5-4):(0.02-0.03).

4. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S12, the mass ratio of melamine to hydroxypropyl acrylate is 1:(1.8-2.1).

5. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S13, the mass ratio of the isocyanate-modified acrylate intermediate to the borosilicate intermediate is 1:(0.4-0.6).

6. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S2, the low residual viscosity modified adhesive is composed of 3-5 parts of butyl acrylate, 3-8 parts of borosilicate modified acrylate, 25-30 parts of isooctyl acrylate, 0.05-0.08 parts of isopropylbenzene hydroperoxide, 0.1-0.3 parts of antioxidant and 0.2-0.4 parts of cross-linking agent.

7. The method for preparing a high temperature resistant, low viscosity and non-residue adhesive protective film according to claim 1, characterized in that: In step S2, the antioxidant is any one of hydroquinone and antioxidant TH-1790; and the cross-linking agent is isophorone diisocyanate.

8. A high temperature resistant, low viscosity and non-residue adhesive protective film prepared by the preparation method according to any one of claims 1 to 7.

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