High-temperature-resistant high-cohesiveness polyamide-imide resin, preparation method thereof and protective film

Abstract

The invention discloses high-temperature-resistant high-cohesiveness polyamide-imide resin, a preparation method thereof and a protective film. Monomers with acyl chloride as terminal groups are introduced, so that an imide group on a polyamide-imide main chain is gradually substituted by an amide group, and the high-temperature-resistant high-cohesiveness polyamide-imide resin is obtained; according to the present invention, the amide group accounts for more than 50% and less than 65% of the total mole number of the amide group and the imide group, such that the heat resistance of the resin is not substantially reduced while the adhesion of the protection film and the base material is increased, the glass-transition temperature of the resin is 170-210 DEG C, and the decomposition temperature is more than 450 DEG C. According to the invention, the siloxane coupling agent is added to seal the end of the polyamide-imide resin, so that the end of the polyamide-imide resin is a siloxane group, and the siloxane group is easy to hydrolyze and can form a covalent bond with the surface of the polyimide-based membrane, so that the adhesive force between the resin and the polyimide-based membrane is increased, and the resin is prevented from falling off.

Description

Technical Field

[0001] This invention relates to the field of adhesive materials, and particularly to a high-temperature resistant, high-adhesion polyamide-imide resin, its preparation method, and a protective film thereof. Background Technology

[0002] Currently, most high-temperature resistant protective films on the market consist of an adhesive layer and a polyimide base film. The adhesives are epoxy resin and acrylic resin, but both of these adhesives are not heat-resistant and will decompose at high temperatures, causing the protective film to lose its adhesion and detach from the substrate, thus failing to protect the object. Researchers then considered thermoplastic polyimide (TPI), but the glass transition temperature of most thermoplastic polyimides is above 250℃, the hot-press activation temperature needs to be above 300℃, and the adhesion is less than 200gf, which cannot meet the requirements.

[0003] Polyamide imide (PAI) is a class of polymer materials derived from polyimide. Its molecular structure contains both imide and amide structures, which not only retains the excellent heat resistance and mechanical properties of polyimide, but also increases the good adhesion and processing performance of polyamide materials.

[0004] Patent CN 119931586 A discloses a method for preparing a polyamide-imide copolymer resin adhesive and a temporary encapsulation adhesive film for semiconductor devices. The preparation method is as follows: a flexible long-chain aromatic diamine, a siloxane diamine, 4,4'-dithiodiphenylamine, trimellitic anhydride acyl chloride, and a flexible long-chain dianhydride are reacted in an organic solvent for a period of time, followed by end-capping with a capping agent; then, a catalyst is added for imidization treatment to obtain a polyamide-imide copolymer resin; finally, a siloxane epoxy resin is added and stirred until uniformly mixed to obtain the polyamide-imide copolymer resin adhesive; it has excellent heat resistance and adhesion, and leaves no residue after peeling.

[0005] In the preparation method of the polyamide-imide copolymer resin adhesive described in patent CN 119931586 A, since the molar ratio of trimellitic anhydride acyl chloride to flexible long-chain dianhydride monomer is 1.0~2.5:1, the percentage of amide groups in the total molar number of amide groups and imide groups in the adhesive does not exceed 37%. Even with the addition of siloxane resin (Shin-Etsu-KBE903 or Shin-Etsu-KBE9103), its peel strength is still lower than 220gf. Secondly, the polyamide-imide copolymer resin has been capped by the end-capping agent (phthalic anhydride), and the siloxane resin can no longer react with the polyamide-imide-polyimide. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a high-temperature resistant, high-adhesion polyamide-imide resin, its preparation method, and a protective film. The resin prepared by this invention has a glass transition temperature of 160℃~210℃ and a decomposition temperature greater than 400℃; after being coated onto a polyimide-based film and cured, a protective film is obtained, which is then hot-pressed onto a substrate, exhibiting a peel force greater than 250gf.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In its first aspect, the present invention provides a method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, comprising the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat the mixture to react. Finally, add 2-10 parts of a capping agent to react and obtain a polyamide imide acid solution. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React under heating to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent to precipitate it. After filtration and drying, polyamide-imide powder is obtained. S4. The powder obtained in step S3 is added to an organic solvent for dilution and mixed evenly to obtain the high-temperature resistant and high-adhesion polyamide-imide resin.

[0008] Preferably, the preparation method of the high-temperature resistant and high-adhesion polyamide-imide resin includes the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat to 20-60℃ and react for 1-4 hours. Finally, add 2-10 parts of a capping agent and react for 1-2 hours to obtain a polyamide imide acid solution with a solid content of 5-15%. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React at 60-200℃ for 3-24 hours to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent with a volume of 1 to 10 times the solution volume to precipitate the solution. After filtration, dry the solution at 60 to 200°C for 5 to 24 hours to obtain polyamide-imide powder. S4. The powder obtained in step S3 is added to an organic solvent and diluted to a solid content of 20%~30%. After stirring and ultrasonic mixing, the high-temperature resistant and high-adhesion polyamide-imide resin is obtained.

[0009] Preferably, in step S1: The aromatic diamine monomer is any one or more of 4,4′-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, and 1,3-bis(4-aminophenoxy)benzene; The acyl chloride anhydride monomer is 1,2,4-triphenyltriacyl chloride; The end-capping agent is a siloxane coupling agent selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropylmethyldiethoxysilane.

[0010] Preferably, in step S1, the molar ratio of aromatic diamine monomer: acyl chloride anhydride monomer: capping agent is 96~99:100:1~10.

[0011] Preferably, the siloxane diamine monomer in step S1 is 1,3-bis(aminopropyl)tetramethyldisiloxane, and the diacyl chloride monomer is one or both of isophthaloyl chloride and terephthaloyl chloride.

[0012] Preferably, the polar organic solvent in step S1 is at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide, and the acid-binding agent is at least one of triethylamine and N,N-diisopropylethylamine.

[0013] Preferably, the catalyst in step S2 is at least one of pyridine, isoquinoline, 3-methylpyridine, triethylamine or 2-methylpyridine, and the dehydrating agent is acetic anhydride.

[0014] Preferably, the unsuitable solvent in step S3 is one or more of water, methanol, and ethanol.

[0015] In a second aspect, the present invention provides a high-temperature resistant, high-adhesion polyamide-imide resin, characterized in that it is prepared by the method described above.

[0016] A third aspect of the present invention provides a high-temperature resistant and highly adhesive protective film, comprising a substrate layer and an adhesive layer, wherein the adhesive layer is obtained by coating and curing the high-temperature resistant and highly adhesive polyamide-imide resin as described above on the substrate layer.

[0017] The beneficial effects of this invention are: This invention provides a polyamide-imide resin and its preparation method. By introducing monomers with end groups of acyl chloride, the imide groups on the polyamide-imide backbone are gradually replaced by amide groups. The percentage of amide groups in the total molar number of amide and imide groups is greater than 50% and less than 65%. Without significantly reducing the heat resistance of the resin, the adhesion between the protective film and the substrate is increased. The glass transition temperature of the resin is 170℃~210℃, and the decomposition temperature is greater than 450℃.

[0018] The present invention also adds a siloxane coupling agent to end-cap the polyamide-imide resin, so that the polyamide-imide ends are siloxane groups. The siloxane groups are easily hydrolyzed and can form covalent bonds with the surface of the polyimide film, thereby increasing the adhesion between the resin and the polyimide film and preventing resin de-oxidation. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0020] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0022] This invention provides a high-temperature resistant, high-adhesion polyamide-imide resin and its preparation method, which includes the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat the mixture to react. Finally, add 2-10 parts of a capping agent to react and obtain a polyamide imide acid solution. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React under heating to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent to precipitate it. After filtration and drying, polyamide-imide powder is obtained. S4. Add the powder obtained in step S3 to an organic solvent for dilution, mix evenly, and obtain a high-temperature resistant and highly adhesive polyamide-imide resin.

[0023] In a preferred embodiment, the preparation method of the high-temperature resistant, high-adhesion polyamide-imide resin includes the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat to 20-60℃ and react for 1-4 hours. Finally, add 2-10 parts of a capping agent and react for 1-2 hours to obtain a polyamide imide acid solution with a solid content of 5-15%. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React at 60-200℃ for 3-24 hours to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent with a volume of 1 to 10 times the solution volume to precipitate the solution. After filtration, dry the solution at 60 to 200°C for 5 to 24 hours to obtain polyamide-imide powder. S4. Add the powder obtained in step S3 to an organic solvent and dilute it to a solid content of 20%~30%. After stirring and ultrasonic mixing, a high-temperature resistant and highly adhesive polyamide-imide resin is obtained.

[0024] In a preferred embodiment, the aromatic diamine monomer is any one or more of 4,4′-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, and 1,3-bis(4-aminophenoxy)benzene.

[0025] In a preferred embodiment, the acyl chloride anhydride monomer is 1,2,4-trimethoate anhydride acyl chloride.

[0026] In a preferred embodiment, the capping agent is a siloxane coupling agent selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropylmethyldiethoxysilane.

[0027] In a preferred embodiment, in step S1, the molar ratio of aromatic diamine monomer: acylchloric anhydride monomer: capping agent is 96~99:100:1~10.

[0028] In a preferred embodiment, the siloxane diamine monomer in step S1 is 1,3-bis(aminopropyl)tetramethyldisiloxane, and the diacyl chloride monomer is one or both of isophthaloyl chloride and terephthaloyl chloride.

[0029] In a preferred embodiment, the polar organic solvent in step S1 is at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide, and the acid-binding agent is at least one of triethylamine and N,N-diisopropylethylamine.

[0030] In a preferred embodiment, the catalyst in step S2 is at least one of pyridine, isoquinoline, 3-methylpyridine, triethylamine or 2-methylpyridine, and the dehydrating agent is acetic anhydride.

[0031] In a preferred embodiment, the unsuitable solvent in step S3 is one or more of water, methanol, and ethanol.

[0032] In a preferred embodiment, the polyamide-imide resin prepared by the above method has a glass transition temperature of 170°C to 210°C and a decomposition temperature greater than 450°C.

[0033] In a second aspect, the present invention provides a high-temperature resistant, high-adhesion polyamide-imide resin, characterized in that it is prepared by the method described above.

[0034] A third aspect of the present invention provides a high-temperature resistant and highly adhesive protective film, comprising a substrate layer and an adhesive layer, wherein the adhesive layer is obtained by coating and curing the high-temperature resistant and highly adhesive polyamide-imide resin as described above onto the substrate layer.

[0035] In a preferred embodiment, the substrate layer is a polyimide-based film with a thickness of 25 μm, and the adhesive layer has a thickness of 2 μm.

[0036] In the process of preparing polyamide-imide resin, this invention introduces monomers with acyl chloride end groups, so that the imide groups on the polyamide-imide main chain are gradually replaced by amide groups, and the percentage of amide groups in the total molar number of amide groups and imide groups is greater than 50% and less than 65%.

[0037] In the process of preparing polyamide-imide resin, the present invention also introduces a siloxane coupling agent to end the resin, so that the polyamide-imide ends are siloxane groups, and the percentage of siloxane groups in the total molar number of amide groups is 1~10%.

[0038] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0039] The abbreviations for each substance in the various embodiments and comparative examples are as follows: BAPP: 2,2-bis[4-(3-aminophenoxy)phenyl]propane; APDS: 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; ET3N: Triethylamine; TMAC: 1,2,4-Trimellitic trihydric anhydride chloride; ICI: Isophthaloyl chloride; KH550: γ-aminopropyltriethoxysilane; DMF: N,N-dimethylformamide; NMP: N-methylpyrrolidone.

[0040] In the following examples and comparative examples, a 250ml three-necked flask was used as the reaction vessel, which was equipped with a matching tetrafluoroethylene stirrer as a stirring device. In order to prevent moisture from entering the reaction system, nitrogen gas was injected into the reaction vessel.

[0041] Example 1 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin includes the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0487mol BAPP and 0.0055mol APDS and stir for 30min under 0℃ ice-water bath conditions to dissolve. Then add 0.0554mol ET3N to the above solution, followed by adding a mixture of 0.0498mol TMAC and 0.0055mol ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0022mol KH550 and react for 1h to obtain a polyamide imide acid solution.

[0042] S2. Add 0.0748 mol of acetic anhydride and 0.0748 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0043] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0044] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain high temperature resistant and high adhesion polyamide-imide resin.

[0045] Example 2 In this embodiment, a 250ml three-necked flask is used as the reaction vessel, and a matching tetrafluoroethylene stirrer is installed in the reaction vessel as a stirring device. At the same time, in order to prevent water from mixing into the reaction system, nitrogen gas needs to be injected into the reaction vessel.

[0046] A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent. Add 0.0431mol BAPP and 0.0132mol APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then, add 0.0574mol ET3N to the above solution, followed by a mixture of 0.0517mol TMAC and 0.0057mol ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0023mol KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0047] S2. Add 0.0775 mol of acetic anhydride and 0.0775 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0048] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0049] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0050] Example 3 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0488mol of BAPP and 0.0055mol of APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then, add 0.0554mol of ET3N to the above solution, followed by a mixture of 0.0444mol of TMAC and 0.0111mol of ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0022mol of KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0051] S2. Add 0.0665 mol of acetic anhydride and 0.0665 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0052] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0053] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0054] Example 4 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0485mol BAPP and 0.0056mol APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then add 0.0558mol ET3N to the above solution, followed by a mixture of 0.0502mol TMAC and 0.0056mol ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0033mol KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0055] S2. Add 0.0753 mol of acetic anhydride and 0.0753 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0056] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0057] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0058] Example 5 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0487mol BAPP and 0.0055mol APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then add 0.0554mol ET3N to the above solution, followed by a mixture of 0.0498mol TMAC and 0.0055mol ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0033mol KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0059] S2. Add 0.0748 mol of acetic anhydride and 0.0748 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0060] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0061] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0062] Comparative Example 1 The difference between this comparative example and Example 1 is that the coupling agent KH550 was not added, while the rest remained the same.

[0063] Comparative Example 2 The difference between this comparative example and Example 1 is that the amounts of TMAc, ICI, and ET3N were adjusted to 0.0553 mol, 0 mol, and 0.0553 mol, respectively, while the rest remained unchanged.

[0064] Comparative Example 3 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0398mol of BAPP and 0.0176mol of APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then add 0.0586mol of ET3N to the above solution, followed by a mixture of 0.0527mol of TMAC and 0.0059mol of ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0023mol of KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0065] S2. Add 0.0779 mol of acetic anhydride and 0.0779 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0066] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0067] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0068] Comparative Example 4 A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized by comprising the following steps: S1. First, add 187g of N,N-dimethylformamide (DMF) to the above container as a reaction solvent, then add 0.0489mol BAPP and 0.0056mol APDS and stir for 30min at 0℃ in an ice-water bath to dissolve. Then add 0.055mol ET3N to the above solution, followed by a mixture of 0.0389mol TMAC and 0.0167mol ICI in three portions. After complete dissolution, raise the temperature to 25℃ and continue the reaction for 2h. Finally, add 0.0022mol KH550 and react for 1h to obtain a polyamide-imide acid solution.

[0069] S2. Add 0.0583 mol of acetic anhydride and 0.0583 mol of isoquinoline to the polyamide imide acid solution, and raise the reaction temperature to 80℃ and react for 12 h to obtain a siloxane-terminated polyamide imide solution.

[0070] S3. After cooling the polyamide-imide solution obtained in step S2 to room temperature, slowly pour it into 1000 ml of ethanol and stir. After the powder precipitates, filter it and dry it at 60°C for 12 h to obtain polyamide-imide powder.

[0071] S4. Add polyamide-imide powder to NMP, dilute to a solid content of 20%, stir and ultrasonically mix evenly to obtain polyamide-imide resin.

[0072] Table 1 shows the molar ratios of some raw materials used in each embodiment and comparative example: Table 1 Application example: The polyamide-imide resins prepared in the various examples and comparative examples were coated with a thickness of 2 μm onto a 25 μm thick polyimide film, and baked at 120°C for 2 min to obtain a protective film. The following performance tests were then performed on the film: (1) Peel strength test: Using a hot press, the protective film was bonded to an aluminum plate at 215℃, 0.7MPa and 30S to obtain a sample for peel strength test. The protective film was peeled off the sample at a speed of 50mm / min in the 180° direction to test its peel strength and the state of residual adhesive.

[0073] (2) Decomposition temperature Td5% test: Take 5~10mg of polyamide-imide powder sample and place it in an aluminum pan. Place it in a thermogravimetric analyzer and, under nitrogen atmosphere, raise the temperature from room temperature to 800℃ at 20℃ / min to test its decomposition temperature Td5.

[0074] (3) Glass transition temperature Tg: The instrument used for testing is a differential scanning calorimeter. Take 5~10mg of polyamide-imide powder sample, and test the Tg point of polyamide-imide powder at a nitrogen flow rate of 60mL / min, a heating rate of 10℃ / min, and a temperature range of 30-400℃.

[0075] The decomposition temperature, glass transition temperature, peel strength, and residual adhesive state of the powders in the above embodiments and comparative examples were tested. The test results are shown in Table 2. Table 2 As can be seen from the data in the table above, the polyamide-imide resin protective film provided in Examples 1-5 of the present invention has excellent heat resistance, adhesion and low residual adhesive rate.

[0076] In Comparative Example 1, because no siloxane coupling agent was added and the polyamide-imide resin was not end-capped, the polyamide-imide could not form strong covalent bonds with the surface of the polyimide-based film, resulting in a decrease in the adhesion between the protective film and the aluminum plate to 201gf / 25mm, causing resin de-sterilization and leaving residue on the aluminum plate.

[0077] In Comparative Example 2, since no diacyl chloride monomer was added, the percentage of amide groups in the total molar number of amide and imide groups was only 50%. The proportion of amide groups was too low, resulting in an adhesion strength of only 233gf / 25mm between the protective film and the aluminum plate.

[0078] In Comparative Example 3, the heat resistance of the polyamide-imide powder decreased due to the fact that the amount of siloxane diamine soft monomer exceeded 30 parts, with Tg only 168℃ and Td5% less than 450℃. After peeling, there was residual adhesive on the aluminum plate.

[0079] In Comparative Example 4, since the number of diacyl chloride monomers was 30 parts, the percentage of amide groups in the total molar number of amide and imide groups was 65%. The amide ratio was too high, which led to a decrease in the heat resistance of the polyamide-imide powder (Td5%), which was less than 450℃. After peeling, there was residual adhesive on the metal aluminum plate.

[0080] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for preparing a high-temperature resistant, high-adhesion polyamide-imide resin, characterized in that, Includes the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat the mixture to react. Finally, add 2-10 parts of a capping agent to react and obtain a polyamide imide acid solution. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React under heating to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent to precipitate it. After filtration and drying, polyamide-imide powder is obtained. S4. The powder obtained in step S3 is added to an organic solvent for dilution and mixed evenly to obtain the high-temperature resistant and high-adhesion polyamide-imide resin.

2. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 1, characterized in that, Includes the following steps: S1. By weight, under an inert gas atmosphere and ice-water bath conditions, dissolve 70-95 parts of an aromatic diamine monomer and 5-30 parts of a siloxane diamine monomer mixture in a polar organic solvent, add 50-200 parts of an acid-binding agent, and after complete dissolution, add 80-95 parts of an acyl chloride anhydride monomer and 5-20 parts of a diacyl chloride monomer mixture in batches, and after complete dissolution, heat to 20-60℃ and react for 1-4 hours. Finally, add 2-10 parts of a capping agent and react for 1-2 hours to obtain a polyamide imide acid solution with a solid content of 5-15%. S2. By weight, add 100-300 parts of catalyst and 100-300 parts of dehydrating agent to the polyamide imide acid solution obtained in step S1, and carry out imidization. React at 60-200℃ for 3-24 hours to obtain a siloxane-terminated polyamide imide solution. S3. Pour the solution obtained in step S2 into a poor solvent with a volume of 1 to 10 times the solution volume to precipitate the solution. After filtration, dry the solution at 60 to 200°C for 5 to 24 hours to obtain polyamide-imide powder. S4. The powder obtained in step S3 is added to an organic solvent and diluted to a solid content of 20%~30%. After stirring and ultrasonic mixing, the high-temperature resistant and high-adhesion polyamide-imide resin is obtained.

3. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 2, characterized in that, In step S1: The aromatic diamine monomer is any one or more of 4,4′-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, and 1,3-bis(4-aminophenoxy)benzene; The acyl chloride anhydride monomer is 1,2,4-triphenyltriacyl chloride; The end-capping agent is a siloxane coupling agent selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropylmethyldiethoxysilane.

4. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 3, characterized in that, In step S1, the molar ratio of aromatic diamine monomer: acyl chloride anhydride monomer: capping agent is 96~99:100:1~10.

5. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 1, characterized in that, In step S1, the siloxane diamine monomer is 1,3-bis(aminopropyl)tetramethyldisiloxane, and the diacyl chloride monomer is one or both of isophthaloyl chloride and terephthaloyl chloride.

6. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 1, characterized in that, The polar organic solvent in step S1 is at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide, and the acid-binding agent is at least one of triethylamine and N,N-diisopropylethylamine.

7. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 1, characterized in that, The catalyst in step S2 is at least one of pyridine, isoquinoline, 3-methylpyridine, triethylamine or 2-methylpyridine, and the dehydrating agent is acetic anhydride.

8. The method for preparing the high-temperature resistant, high-adhesion polyamide-imide resin according to claim 1, characterized in that, The unsuitable solvent in step S3 is one or more of water, methanol, and ethanol.

9. A high-temperature resistant, high-adhesion polyamide-imide resin, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. A high-temperature resistant and highly adhesive protective film, characterized in that, It includes a substrate layer and an adhesive layer, wherein the adhesive layer is obtained by coating and curing the high-temperature resistant and high-adhesion polyamide-imide resin as described in claim 9 onto the substrate layer.

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