Polyamide acid slurry as well as preparation method and application thereof

Abstract

The invention provides polyamide acid slurry as well as a preparation method and application thereof, preparation monomers of the polyamide acid slurry comprise a diamine monomer and a dianhydride monomer, and the diamine monomer comprises long straight chain aliphatic diamine and aromatic diamine; the long straight chain aliphatic diamine is # imgabs0 #, and n is more than or equal to 7 and less than or equal to 20. The diamine monomer adopts long straight-chain aliphatic diamine and aromatic diamine, and the long straight-chain aliphatic diamine, the aromatic diamine and the dianhydride monomer are subjected to polymerization reaction together to prepare the polyamide acid slurry, so that the reactivity of the monomers is reduced, the polymerization among molecules is hindered, and the viscosity of a polymerization reaction system is effectively adjusted; therefore, the polyamide acid slurry has high solid content and low viscosity at the same time. According to the preparation method, the polymerization reaction time required for preparing the polyamide acid slurry is shortened, and the production efficiency is improved; and the prepared polyamide acid slurry can be normally cast to form a film, so that the leveling property and operability of the polyamide acid slurry are improved, and the subsequently formed film material has excellent performance.

Description

Technical Field

[0001] The present application relates to the field of polymer materials, and in particular to a polyamic acid slurry and a preparation method and application thereof. Background Art

[0002] The most commonly used method for synthesizing polyimide (PI) is to synthesize polyimide from polyamic acid (PAA) by thermal or chemical imidization. Polyamic acid solution is usually synthesized from dianhydride and diamine in aprotic polar solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and other solvents at low temperatures, such as -10°C to room temperature.

[0003] Polyamic acid slurry is a polyimide precursor solution. The relative molecular weight of polyamic acid slurry obtained by the existing process is generally high, and the corresponding slurry viscosity is also high, which is not easy to process and it is difficult to obtain a polyimide film with uniform thickness. The viscosity of polyamic acid slurry is mainly affected by the solid content and relative molecular weight of the system, but reducing the solid content will lead to a decrease in the film thickness of the polyamic acid slurry. Summary of the invention

[0004] Based on this, it is necessary to provide a polyamic acid slurry and a preparation method and application thereof, so as to reduce the viscosity of the polyamic acid slurry under the premise of high solid content.

[0005] In one aspect of the present application, a polyamic acid slurry is provided, wherein the monomers for preparing the polyamic acid slurry include diamine monomers and dianhydride monomers, wherein the diamine monomers include long straight-chain aliphatic diamines and aromatic diamines;

[0006] The long straight chain fatty diamine is , 7≤n≤20.

[0007] The monomers for preparing the above-mentioned polyamic acid slurry include diamine monomers and dianhydride monomers. The diamine monomers use long straight-chain fatty diamines and aromatic diamines. The long straight-chain fatty diamines, aromatic diamines and dianhydride monomers are polymerized together to prepare the polyamic acid slurry, which reduces the reactivity of the monomers, hinders the polymerization between molecules, and effectively adjusts the viscosity of the polymerization reaction system, so that the polyamic acid slurry has a high solid content and low viscosity. In addition, long straight-chain fatty diamines and aromatic diamines are used together as diamines to prepare the polyamic acid slurry. The obtained polyamic acid slurry can be cast into a film normally, which improves the leveling and operability of the polyamic acid slurry, and the subsequent film material has excellent performance.

[0008] In some embodiments, the long straight chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

[0009] In some embodiments, the molar ratio of the long straight-chain fatty diamine to the aromatic diamine is 1:0.1-1.

[0010] In some embodiments, the molar ratio of the long straight-chain fatty diamine to the aromatic diamine is 1:0.1-0.3.

[0011] In some embodiments, the long straight chain fatty diamine has the general structural formula:

[0012]

[0013] Among them, 0≤m≤13.

[0014] In some embodiments, the aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

[0015] In some embodiments, the dianhydride monomer is selected from at least one of bisphenol A diether dianhydride and pyromellitic acid dianhydride.

[0016] In a second aspect of the present application, a method for preparing a polyamic acid slurry comprises the following steps:

[0017] S1: dissolving long straight chain aliphatic diamine and aromatic diamine in a solvent;

[0018] S2: after the long straight-chain fatty diamine and the aromatic diamine are dissolved, adding the dianhydride monomer to carry out polymerization reaction to obtain the polyamic acid slurry;

[0019] The long straight chain fatty diamine is , 7≤n≤20.

[0020] A polyamic acid slurry is prepared by dissolving a long straight-chain fatty diamine and an aromatic diamine and then adding a dianhydride monomer for polymerization reaction. No additional additives are needed, and the polymerization reaction time required for preparing the polyamic acid slurry can be shortened. The synthesis time for preparing the polyamic acid slurry in the traditional process is usually more than 20 hours. In the preparation method, the reaction time can be controlled within 5 hours to 12 hours, thereby improving the production efficiency. Moreover, the prepared polyamic acid slurry can be normally cast into a film, thereby improving the leveling and operability of the polyamic acid slurry, and the subsequent formed film material has excellent performance.

[0021] In some embodiments, in S2, the polymerization reaction temperature is 65°C to 100°C.

[0022] In some embodiments, in S2, the polymerization reaction time is 5 h to 12 h.

[0023] In some embodiments, the long straight chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

[0024] In some embodiments, the aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

[0025] In some embodiments, the dianhydride monomer is selected from at least one of bisphenol A diether dianhydride and pyromellitic acid dianhydride.

[0026] In some embodiments, the aromatic diamine includes 4,4′-diaminodiphenylmethane, the dianhydride monomer includes bisphenol A diether dianhydride and pyromellitic acid dianhydride, and the molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A diether dianhydride and the pyromellitic acid dianhydride is 0.1~1:0.1~1:0.4~0.9:0.1~0.6.

[0027] In some embodiments, the molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A diether dianhydride and the pyromellitic acid dianhydride is 1:0.1-0.3:0.4-0.9:0.1-0.6.

[0028] In some embodiments, the solvent includes one or more of N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone and N,N-dimethylformamide.

[0029] In some embodiments, the solvent includes N-methylpyrrolidone and N,N-dimethylacetamide, and the N-methylpyrrolidone and the N,N-dimethylacetamide are mixed in a mass ratio of 3:7 to 9:1.

[0030] In some embodiments, in S1, the solvent is heated to a temperature of 50°C to 100°C.

[0031] The third aspect of the present application provides a polyamic acid slurry, which is prepared by the preparation method described in the second aspect.

[0032] The fourth aspect of the present application provides a polyimide film, which is prepared by coating the polyamic acid slurry described in the third aspect and then subjecting it to thermal imidization or chemical imidization; or the preparation monomers include diamine monomers and dianhydride monomers, and the diamine monomers include long straight-chain fatty diamines and aromatic diamines.

[0033] A fifth aspect of the present application provides a resin product comprising the polyimide film as described in the fourth aspect. DETAILED DESCRIPTION

[0034] The polyamic acid slurry of the present invention and its preparation method and application are further described in detail below in conjunction with specific examples. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0036] The optional scope of the terms "and / or", "or / and", and "and / or" used in this article includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, said any and all combinations include any combination of any two related listed items, any more related listed items, or all related listed items.

[0037] As used herein, "at least one" means one, two or more than two.

[0038] In the present invention, "the first aspect", "the second aspect", "the third aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0039] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0040] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0041] "Aromatic diamine" refers to a compound having two amino groups. And an organic compound with an aromatic ring structure.

[0042] The term "aromatic" refers to an aromatic hydrocarbon group derived by removing one or more hydrogen atoms from an aromatic ring compound.

[0043] "Long straight-chain fatty diamine" refers to a diamine containing two amino groups, and the two amino groups are connected to a long straight-chain fatty hydrocarbon group. In this article, a long straight-chain fatty hydrocarbon group refers to a fatty hydrocarbon group with a carbon number of ≥7 in the main chain.

[0044] The long straight chain in the term "long straight chain fatty diamine" refers to a relatively long carbon chain without branches in the molecular structure.

[0045] Polyamic acid slurry is a polyimide precursor solution. The polyamic acid slurry currently produced generally has a high molecular weight and high viscosity, making it difficult to process and obtain a uniform film. Reducing the viscosity by reducing the solid content will result in a decrease in the film thickness of the polyamic acid slurry, which is not conducive to high solid content and low viscosity applications. In addition, the traditional process for preparing polyamic acid has a long synthesis time, generally more than 20 hours, which seriously affects the production efficiency and economic benefits of the product.

[0046] One embodiment of the present application, one aspect of the present application, provides a polyamic acid slurry, the preparation monomers include diamine monomers and dianhydride monomers, the diamine monomers include long straight-chain fatty diamines and aromatic diamines; the long straight-chain fatty diamines are , 7≤n≤20.

[0047] The monomers for preparing the above-mentioned polyamic acid slurry include diamine monomers and dianhydride monomers. The diamine monomers use long straight-chain fatty diamines and aromatic diamines. The long straight-chain fatty diamines, aromatic diamines and dianhydride monomers are polymerized together to prepare the polyamic acid slurry, which reduces the reactivity of the monomers, hinders the polymerization between molecules, and effectively adjusts the viscosity of the polymerization reaction system, so that the polyamic acid slurry has a high solid content and low viscosity. In addition, long straight-chain fatty diamines and aromatic diamines are used together as diamines to prepare the polyamic acid slurry. The obtained polyamic acid slurry can be cast into a film normally, which improves the leveling and operability of the polyamic acid slurry, and the subsequent film material has excellent performance.

[0048] In some embodiments, the long straight chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

[0049] In some embodiments, the molar ratio of the long straight chain fatty diamine to the aromatic diamine is 1:0.1~1. The polyamic acid slurry prepared by mixing the long straight chain fatty diamine and the aromatic diamine in a molar ratio of 1:0.1~1 as diamine monomers has a high solid content and low viscosity, and has excellent film-forming properties and obtained film material properties.

[0050] In some embodiments, the molar ratio of the long straight chain fatty diamine to the aromatic diamine is 1:0.1-0.3. The long straight chain fatty diamine and the aromatic diamine are mixed in a molar ratio of 1:0.1-3 as diamine monomers to obtain unexpectedly good results in reducing the viscosity of the polyamic acid slurry, and the obtained polyamic acid slurry has low viscosity and good leveling properties.

[0051] In some embodiments, the long straight chain fatty diamine has the general structural formula:

[0052]

[0053] Among them, 0≤m≤13.

[0054] In some embodiments, the aromatic diamine is selected from at least one of 4,4'-methylenediaminodiphenylmethane (MDA), 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

[0055] The structural formula of MDA is as follows:

[0056]

[0057] The structural formula of 4,4'-diaminodiphenyl ether is as follows:

[0058]

[0059] The structural formula of 3,4-diaminodiphenyl ether is as follows:

[0060]

[0061] The structural formula of p-phenylenediamine is as follows:

[0062]

[0063] The structural formula of m-phenylenediamine is as follows:

[0064]

[0065] The structural formula of 4,4'-diaminodiphenyl sulfone is as follows:

[0066]

[0067] The structural formula of 4,4'-diamino-2,2'-dimethylbiphenyl is as follows:

[0068]

[0069] The structural formula of 4,4''-diaminoterphenyl is as follows:

[0070]

[0071] In some embodiments, the dianhydride monomer is selected from at least one of bisphenol A diether dianhydride (BPADA) and pyromellitic acid dianhydride (PMDA).

[0072] The structural formula of BPADA is as follows:

[0073]

[0074] The structural formula of PMDA is as follows:

[0075]

[0076] The second aspect of the present application provides a method for preparing a polyamic acid slurry, comprising the following steps:

[0077] S1: dissolving long straight chain aliphatic diamine and aromatic diamine in a solvent;

[0078] S2: after the long straight-chain fatty diamine and the aromatic diamine are dissolved, adding the dianhydride monomer to carry out polymerization reaction to obtain the polyamic acid slurry;

[0079] The long straight chain fatty diamine is , 7≤n≤20.

[0080] A polyamic acid slurry is prepared by dissolving a long straight-chain fatty diamine and an aromatic diamine and then adding a dianhydride monomer for polymerization reaction. No additional additives are needed, and the polymerization reaction time required for preparing the polyamic acid slurry can be shortened. The synthesis time for preparing the polyamic acid slurry in the traditional process is usually more than 20 hours. In the preparation method, the reaction time can be controlled within 5 hours to 12 hours, thereby improving the production efficiency. Moreover, the prepared polyamic acid slurry can be normally cast into a film, thereby improving the leveling and operability of the polyamic acid slurry, and the subsequent formed film material has excellent performance.

[0081] In some embodiments, in S2, the polymerization reaction temperature is 65°C to 100°C.

[0082] The traditional preparation process of polyamic acid slurry is usually carried out at a relatively low temperature (-10℃~25℃), and increasing the polymerization reaction temperature to 65℃~100℃ not only further shortens the reaction time and improves the production efficiency of polyamic acid slurry, but also effectively adjusts the viscosity of the polymerization reaction system and successfully reduces the viscosity of polyamic acid slurry, thereby improving the leveling and operability of polyamic acid slurry, making the thickness of the subsequently obtained polyimide film controllable, the texture uniform and the number of defects few.

[0083] As an example, the polymerization reaction temperature can be 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C and 100°C, or it can be within the range formed by any two of the above point values ​​as end values.

[0084] Furthermore, the polymerization reaction temperature is preferably 70° C. to 90° C. At a polymerization reaction temperature of 70° C. to 90° C., the viscosity of the polyamic acid slurry is further reduced, and the leveling property and operability of the polyamic acid slurry are further improved.

[0085] In some embodiments, in S2, the polymerization reaction time is 5 h to 12 h.

[0086] As an example, the polymerization reaction time can be 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h and 12 h, or it can be in the range of any two of the above point values ​​as end values. The synthesis time of the traditional process for preparing polyamic acid is usually more than 20 hours. In the preparation method, the reaction time can be controlled within 5h~12h, which improves the production efficiency. Within the reaction time of 5h~12h, the leveling and operability of the polyamic acid slurry are excellent.

[0087] In some embodiments, the long straight chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

[0088] In some embodiments, the aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

[0089] In some embodiments, the dianhydride monomer is selected from at least one of bisphenol A diether dianhydride and pyromellitic acid dianhydride.

[0090] In some embodiments, the aromatic diamine includes 4,4′-diaminodiphenylmethane, the dianhydride monomer includes bisphenol A diether dianhydride and pyromellitic acid dianhydride, and the molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A diether dianhydride and the pyromellitic acid dianhydride is 0.1~1:0.1~1:0.4~0.9:0.1~0.6.

[0091] In some embodiments, the molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A diether dianhydride and the pyromellitic acid dianhydride is 1:0.1-0.3:0.4-0.9:0.1-0.6.

[0092] In some embodiments, the solvent includes one or more of N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone and N,N-dimethylformamide.

[0093] In some embodiments, the solvent includes N-methylpyrrolidone and N,N-dimethylacetamide, and the N-methylpyrrolidone and the N,N-dimethylacetamide are mixed in a mass ratio of 3:7 to 9:1. Using N-methylpyrrolidone and N,N-dimethylacetamide in a mass ratio of 3:7 to 9:1 as a mixed solvent, an unexpectedly good effect is obtained in reducing the viscosity of the polyamic acid slurry, and the viscosity of the polyamic acid slurry is reduced under the premise of high solid content, and the obtained polyamic acid slurry has low viscosity and good leveling properties.

[0094] In some embodiments, in S1, the solvent is heated to a temperature of 50°C to 100°C.

[0095] Furthermore, the solvent is preferably heated to a temperature of 65°C to 100°C.

[0096] Understandably, according to the melting point of the diamine monomer, the monomer dissolution time can be reduced by raising the temperature to its melting point during the dissolution of the diamine monomer. After the diamine monomer is completely dissolved, the dianhydride monomer is added for copolymerization without lowering the polymerization temperature.

[0097] The third aspect of the present application provides a polyamic acid slurry, which is prepared by the preparation method described in the second aspect.

[0098] The fourth aspect of the present application provides a polyimide film, which is prepared by coating the polyamic acid slurry described in the third aspect and then subjecting it to thermal imidization or chemical imidization; or the preparation monomers include diamine monomers and dianhydride monomers, and the diamine monomers include long straight-chain fatty diamines and aromatic diamines.

[0099] A fifth aspect of the present application provides a resin product comprising the polyimide film as described in the fourth aspect.

[0100] The following are specific embodiments.

[0101] Example 1

[0102] Under the protection of nitrogen atmosphere, 40 g of N-methylpyrrolidone was added to a clean and dry reactor, heated to 90°C, 2.5324 g of 1,11-undecanediamine and 0.6804 g of MDA were added, and after stirring until completely dissolved, 5.3051 g of BPADA and 1.4821 g of PMDA were added. The reaction temperature was maintained at 90°C and the stirring reaction was continued for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid slurry.

[0103] Example 2

[0104] The preparation method of Example 2 is basically the same as that of Example 1, except that the polymerization reaction time is 24 hours.

[0105] Example 3

[0106] The preparation method of Example 3 is basically the same as that of Example 1, except that the solvent is N,N-dimethylacetamide.

[0107] Example 4

[0108] The preparation method of Example 4 is basically the same as that of Example 1, except that the solvent is a mixture of N-methylpyrrolidone and N,N-dimethylacetamide in a mass ratio of 7:3.

[0109] Example 5

[0110] The preparation method of Example 5 is basically the same as that of Example 1, except that the solvent is a mixture of N-methylpyrrolidone and N,N-dimethylacetamide in a mass ratio of 5:5.

[0111] Example 6

[0112] Under the protection of nitrogen atmosphere, 40 g of mixed solvent (a mixture of N-methylpyrrolidone and N,N-dimethylacetamide in a ratio of 5:5) was added to a clean and dry reactor, heated to 90°C, 3.0107 g of 1,11-undecanediamine and 0.3595 g of MDA were added, and after stirring until completely dissolved, 4.6719 g of BPADA and 1.9579 g of PMDA were added. The reaction temperature was maintained at 90°C and the stirring reaction was continued for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid slurry.

[0113] Example 7

[0114] The preparation method of Example 7 is basically the same as that of Example 6, except that the solvent is a mixture of N-methylpyrrolidone and N,N-dimethylacetamide in a ratio of 3:7.

[0115] Example 8

[0116] The preparation method of Example 8 is basically the same as that of Example 1, except that the polymerization reaction temperature is 65°C.

[0117] Example 9

[0118] The preparation method of Example 9 is basically the same as that of Example 1, except that the polymerization reaction temperature is 100°C.

[0119] Example 10

[0120] The preparation method of Example 10 is basically the same as that of Example 1, except that the polymerization reaction temperature is 70°C.

[0121] Embodiment 11

[0122] The preparation method of Example 11 is basically the same as that of Example 1, except that the polymerization reaction time is 5 hours.

[0123] Example 12

[0124] The preparation method of Example 12 is basically the same as that of Example 1, except that the polymerization reaction time is 12 hours.

[0125] Example 13

[0126] The preparation method of Example 13 is basically the same as that of Example 1, except that the long straight-chain fatty diamine is 1,9-nonanediamine.

[0127] Comparative Example 1

[0128] Under the protection of nitrogen atmosphere, 40 g of N-methylpyrrolidone was added to a clean and dry reactor, heated to 70°C, 1,11-undecanediamine was added, and after stirring until completely dissolved, 5.3303 g of BPADA and 1.4892 g of PMDA were added. The temperature was lowered to 10°C and stirred for 24 hours to obtain a light yellow homogeneous and transparent polyamic acid slurry.

[0129] Comparative Example 2

[0130] Under the protection of nitrogen atmosphere, 40 g of N,N-dimethylacetamide was added to a clean and dry reactor, heated to 70°C, 3.3390 g of MDA was added, and after stirring until completely dissolved, 5.2064 g of BPADA and 1.4546 g of PMDA were added. The temperature was lowered to 10°C and stirred for 24 hours to obtain a light yellow homogeneous and transparent polyamic acid slurry.

[0131] The viscosity and solid content of the slurries prepared in Examples 1 to 13 and Comparative Examples 1 to 2 were tested. The test results are shown in Table 1 below.

[0132] Table 1

[0133]

[0134] As can be seen from Table 1 above, the viscosity of the polyamic acid slurry prepared by using long straight-chain fatty diamine and aromatic diamine as diamine monomers in Examples 1 to 13 is significantly lower than the viscosity of the polyamic acid slurry prepared by using only long straight-chain fatty diamine as diamine monomer in Comparative Example 1, and is lower than the viscosity of the polyamic acid slurry prepared by using only aromatic diamine as diamine monomer in Comparative Document 2. As can be seen from Example 2, the viscosity increases when the polymerization reaction time is extended to 24 hours, and a low-viscosity polyamic acid slurry can be obtained in 5h~12h; as can be seen from Examples 3 to 7, a polyamic acid slurry with lower viscosity can be obtained by using N-methylpyrrolidone and N,N-dimethylacetamide mixed in a specific proportion as a solvent; as can be seen from Examples 1 to 13, the polyamic acid slurry obtained when the polymerization reaction temperature is 65℃~100℃ has low viscosity under the premise of high solid content, and the effect is better when the temperature is 70℃~90℃.

[0135] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A polyamic acid slurry, characterized in that: The preparation monomers include diamine monomers and dianhydride monomers, wherein the diamine monomers include long straight-chain aliphatic diamines and aromatic diamines; The long straight chain fatty diamine is , 7≤n≤20.

2. The polyamic acid slurry according to claim 1, characterized in that The long straight-chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

3. The polyamic acid slurry according to claim 1, characterized in that The molar ratio of the long straight-chain fatty diamine to the aromatic diamine is 1:0.1-1.

4. The polyamic acid slurry according to any one of claims 1 to 3, characterized in that The molar ratio of the long straight-chain fatty diamine to the aromatic diamine is 1:0.1-0.

3.

5. The polyamic acid slurry according to any one of claims 1 to 3, characterized in that The general structural formula of the long straight chain fatty diamine is: Among them, 0≤m≤13.

6. The polyamic acid slurry according to any one of claims 1 to 3, characterized in that The aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

7. The polyamic acid slurry according to any one of claims 1 to 3, characterized in that The dianhydride monomer is selected from at least one of bisphenol A diether dianhydride and pyromellitic acid dianhydride.

8. A method for preparing a polyamic acid slurry, characterized in that: The following steps are involved: S1: dissolving long straight chain aliphatic diamine and aromatic diamine in a solvent; S2: after the long straight-chain fatty diamine and the aromatic diamine are dissolved, adding the dianhydride monomer to carry out polymerization reaction to obtain the polyamic acid slurry; The long straight chain fatty diamine is , 7≤n≤20.

9. The method for preparing the polyamic acid slurry according to claim 8, characterized in that: In S2, the polymerization reaction temperature is 65°C to 100°C.

10. The method for preparing polyamic acid slurry according to claim 8, characterized in that: In S2, the polymerization reaction time is 5h~12h.

11. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The long straight chain fatty diamine is selected from at least one of 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, 1,18-octadecanediamine, 1,19-nonadecanediamine and 1,20-eicosanediamine.

12. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl and 4,4'-diaminodiphenyl sulfone.

13. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The dianhydride monomer is selected from at least one of bisphenol A diether dianhydride and pyromellitic acid dianhydride.

14. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The aromatic diamine includes 4,4′-diaminodiphenylmethane, the dianhydride monomer includes bisphenol A diether dianhydride and pyromellitic acid dianhydride, and the molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A diether dianhydride and the pyromellitic acid dianhydride is 0.1~1:0.1~1:0.4~0.9:0.1~0.

6.

15. The method for preparing polyamic acid slurry according to claim 14, characterized in that: The molar ratio of the long straight-chain fatty diamine, the 4,4′-diaminodiphenylmethane, the bisphenol A type diether dianhydride and the pyromellitic acid dianhydride is 1:0.1-0.3:0.4-0.9:0.1-0.

6.

16. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The solvent includes one or more of N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone and N,N-dimethylformamide.

17. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: The solvent includes N-methylpyrrolidone and N,N-dimethylacetamide, and the N-methylpyrrolidone and the N,N-dimethylacetamide are mixed in a mass ratio of 3:7 to 9:

1.

18. The method for preparing the polyamic acid slurry according to any one of claims 8 to 10, characterized in that: In the step S1, the solvent is heated to a temperature of 50°C to 100°C.

19. A polyamic acid slurry, characterized in that: The polyamic acid slurry is prepared by the preparation method according to any one of claims 8 to 18.

20. A polyimide film, characterized in that: The polyimide film is prepared by coating the polyamic acid slurry described in claim 19 and then subjecting it to thermal imidization or chemical imidization; or the preparation monomers include diamine monomers and dianhydride monomers, and the diamine monomers include long straight-chain fatty diamines and aromatic diamines.

21. A resin product, characterized in that: Comprising the polyimide film as claimed in claim 20.

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