JP4844097B2 - Polyimide coating composition - Google Patents

Description

  The present invention relates to a polyimide coating composition that is excellent in water and oil repellency of a coating film to be obtained and that has a uniform coating film surface uniformity.

  Coating agents using polyimide resins are widely used for coating materials and film materials for electrical insulating materials and industrial parts because of the good heat resistance and chemical resistance of the processed products. However, the coating film obtained by applying the resin solution to the substrate and volatilizing the solvent tends to have uneven thickness. Moreover, in order to prevent the coating film surface from being soiled, it is required that the surface has antifouling properties and water / oil repellency. In view of this, a polyamide-imide resin coating to which silicone oil is added in order to impart water repellency to the surface has been proposed (see, for example, Patent Document 1).

However, the polyamide-imide paint proposed in Patent Document 1 is obtained by dissolving a polyamide-imide resin by using a specific silicone oil in combination with an organic solvent. As is apparent from the properties of silicone, the resulting coating is obtained. Although the water repellency of the film is obtained, the oil repellency cannot be expressed. In addition, silicone and polyamideimide resin and other highly polar resins are not compatible, and increasing the amount of silicone added tends to bleed out to the surface of the resulting coating, resulting in loss of surface uniformity. The actual situation is that applications are limited, and improvements are required.
JP 2003-327906 A (pages 3 to 5)

  In view of the above circumstances, an object of the present invention is to provide a polyimide coating composition having excellent water / oil repellency of a coating film to be obtained and good uniformity of the coating film surface.

  The inventors of the present invention diligently studied to solve the above-mentioned problems. As a result, by using a fluorine-based compound (polymer) having a specific structure in combination with a polyimide-based resin, the surface is uniform and water-repellent and water-repellent. The inventors have found that a coating film excellent in oiliness can be obtained, and have completed the present invention.

  That is, the present invention includes a fluorinated alkyl group-containing vinyl monomer (A), an amide group-containing vinyl monomer (B) and / or a polyoxyethylene chain-containing vinyl monomer (C). Provided is a polyimide-based coating composition comprising a fluorine-based copolymer (I) obtained by polymerizing monomers (i) and a polyimide-based resin (II). .

  According to the present invention, it is possible to obtain a polyimide resin coating film having good uniformity of the coating film surface and water / oil repellency. The coating film combines water and oil repellency, heat resistance, toughness, and chemical resistance, which are unprecedented, and various coating agents such as heat resistant films, chemical resistant paints, lubricating paints, and heat resistant insulating paints. It can use suitably for an industrial member.

  The fluorinated copolymer (I) used in the present invention has the effect of making the surface of the coating film uniform (making the thick film uniform) and the effect of developing water and oil repellency on the coating film surface. In general, a fluorine-based compound having a perfluoroalkyl group has an effect of enhancing the leveling property of a resin solution or imparting water and oil repellency to the surface of a processed product. The same effect is never expressed, and there is no fluorine compound that can sufficiently exhibit the effect for resin solutions containing resins having a highly polar functional group such as polyimide resin and polyamideimide resin. Was the current situation. The first reason is considered to be the lack of compatibility between the resin and the fluorine-based compound. That is, a compound having a fluorinated alkyl group generally has introduced a philic group for expressing compatibility with an organic solvent, but the philic group focuses on compatibility with a wide range of organic solvents. In many cases, it is not designed considering compatibility with the resin. The aforementioned polyimide resins are known to have high solvent selectivity, that is, compatibility with other general-purpose compounds. Therefore, when a conventional fluorine-based compound with improved compatibility with general-purpose organic solvents and a polyimide-based resin are mixed, the resin solution in a large amount of the organic solvent seems to be uniform. However, even when the solvent content is reduced or after complete volatilization, there is a possibility that the mixture is not uniformly mixed. This is considered to be one of the causes of the problem in the surface uniformity of the coating film obtained from the solvent-drying type resin solution. Therefore, the most important point of the present invention is that the fluorinated alkyl group-containing vinyl monomer (A) and the amide group-containing vinyl monomer (A) and the fluorinated compound having good compatibility with the polyimide resin ( B) and / or the fluorine-containing copolymer (I) obtained by using the polyoxyethylene chain-containing vinyl monomer (C) as an essential monomer.

  The fluorinated alkyl group-containing vinyl monomer (A) is not particularly limited as long as it is a compound having a vinyl group and a fluorinated alkyl group in the molecule, but the raw materials are easily available and the polymerizability is good. Therefore, those containing a (meth) acrylic ester group are preferred. Specifically, the fluorinated (meth) acrylate represented by the following general formula (1) and the par represented by the general formula (2) Examples thereof include fluorinated (meth) acrylate having a plurality of fluoroalkyl groups.

［式中、Ｒ_ｆは同一又は異なる炭素数１〜２０のパーフルオロアルキル基または部分フッ素化アルキル基であり、直鎖状、分岐状または主鎖中に酸素原子が介入したもの、例えば−（ＯＣＦ_２ＣＦ_２）_２ＣＦ（ＣＦ_３）_２等でも良く、Ｒ_１は水素原子、メチル基、塩素原子またはフッ素原子であり、Ｘは２価の連結基で、ｍは０または１である。］
で示されるものが挙げられる。

[Wherein, R _f is the same or different perfluoroalkyl group or partially fluorinated alkyl group having 1 to 20 carbon atoms, linear, branched, or an oxygen atom intervening in the main chain, for example,-( OCF ₂ CF ₂ ) ₂ CF (CF ₃ ) _2, etc., R ₁ is a hydrogen atom, methyl group, chlorine atom or fluorine atom, X is a divalent linking group, and m is 0 or 1. ]
The thing shown by is mentioned.

  Examples of X (divalent linking group) in the general formulas (1) and (2) include the following.

（式中、ｎは１〜１０の整数であり、Ｒ_２は水素原子または炭素数１〜６のアルキル基である。）、
または、

(In the formula, n is an integer of 1 to 10, and R ₂ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Or

  Among these, the following general formula (3) is particularly preferred because it is excellent in water and oil repellency on the surface of the obtained processed product (coating film) and is easily industrially available.

［式中、Ｒ_ｆ’は炭素数１〜２０のパーフルオロアルキル基であり、直鎖状でも分岐状でも良く、Ｒ_１は水素原子又はメチル基である。］
で表される化合物を用いることが好ましく、特にＲ_ｆ’中の炭素数が４〜１２、さらに好ましくは６〜１０の化合物を用いることが好ましい。

[Wherein, R _f ′ is a C 1-20 perfluoroalkyl group, which may be linear or branched, and R ₁ is a hydrogen atom or a methyl group. ]
In particular, it is preferable to use a compound having 4 to 12 carbon atoms, more preferably 6 to 10 carbon atoms in R _f ′.

  Examples of the monomer (1) include compounds represented by the following structural formulas (1-1) to (1-55) and (2-1).

  The fluorinated alkyl group-containing vinyl monomer (A) may be used alone or in combination of two or more.

  The amide group-containing vinyl monomer (B) and polyoxyethylene chain-containing vinyl monomer (C) used in the present invention are the fluorocopolymer (I) obtained and the polyimide resin (II) described later. ). In particular, the amide group-containing vinyl monomer (B) has a high effect and does not impair the transparency of the polyimide resin, and thus exhibits an excellent effect when transparency is required.

  The amide group-containing vinyl monomer (B) is not particularly limited, and examples thereof include dimethylacrylamide, diethylacrylamide, dimethylaminoethylacrylamide, dimethylaminopropylacrylamide, hydroxyethylacrylamide, diacetoneacrylamide, N-isopropylacrylamide, N-vinylpyrrolidone and the like can be mentioned, and only one type may be used, or two or more types may be used simultaneously. Among these, it is preferable to use dimethylacrylamide and N-vinylpyrrolidone from the viewpoint of obtaining a compound with better compatibility with the polyimide resin (II).

  The polyoxyethylene chain-containing vinyl monomer (C) may be any monomer having a polyoxyethylene chain and a vinyl group in one molecule, and a plurality of vinyl groups may be contained. As the vinyl group, those containing a (meth) acrylic ester group are preferred because of the availability of raw materials, good compatibility with blends in various coating compositions, and good polymerization reactivity. The polymerization degree of the polyoxyethylene chain is preferably 1 to 50, and particularly preferably 5 to 30. Further, in the case of a vinyl monomer having a polyoxyethylene chain and another polyoxyalkylene chain, the ratio of the number of oxyethylene chain repeats to the number of other oxyalkylene chain repeats (oxyethylene) / ( It is preferable that (oxyalkylene) is 1 or more, that is, the number of repeating oxyethylene chains is larger.

  Examples of the polyoxyethylene chain-containing vinyl monomer (C) include, for example, mono (meth) acrylic acid ester of polyethylene glycol having a polymerization degree of 1 to 100, and the end is capped with an alkyl group having 1 to 6 carbon atoms. Poly (alkylene glycol) mono- (meth) acrylates having a degree of polymerization of 1 to 100, polyalkylene glycol mono- (meth) acrylates whose ends are capped with alkyl groups having 1 to 6 carbon atoms, such as copolymers of ethylene oxide and propylene oxide. ) Acrylic acid ester and the like.

  Moreover, as a commercial item, NK ester M-20G, M-40G, M-90G, M-230G, AM-90G, AMP-10G, AMP-20G, AMP-60G, Nippon Oil & Fats made by Shin-Nakamura Chemical Co., Ltd. Blemmer PE-90, PE-200, PE-350, AE-90, AE-200, AE-400, PME-100, PME-200, PME-400, PME-1000, PME-4000, 70PEP- 350B, 50PEP-300, 55PET-400, 55PET-800, etc. are mentioned.

  In addition, as a vinyl monomer having two or more vinyl groups in one molecule, polyethylene glycol having a polymerization degree of 1 to 100, polyalkylene glycol having a polymerization degree of 1 to 100 such as a copolymer of ethylene oxide and propylene oxide, etc. Di (meth) acrylic acid ester, polyethylene glycol having a degree of polymerization of 1 to 100 capped with an alkyl group having 1 to 6 carbon atoms, and a terminal such as a copolymer of ethylene oxide and propylene oxide having 1 to 6 carbon atoms And a di (meth) acrylic acid ester of a polyalkylene glycol having a degree of polymerization of 1 to 100 capped with an alkyl group.

  As said polyoxyethylene group containing vinyl-type monomer (C), only 1 type may be used and 2 or more types may be used simultaneously.

  Fluorinated alkyl group-containing vinyl monomer (A) and amide group-containing vinyl monomer (B) in monomers (i), which are raw materials for the fluorinated copolymer (I) used in the present invention. ), The content of the polyoxyethylene chain-containing vinyl monomer (C) is not particularly limited, but from the point of being excellent in the balance of water and oil repellency and surface uniformity of the obtained processed product, The content of the fluorinated alkyl group-containing vinyl monomer (A) in the monomers (i) is 5 to 50% by weight, and the amide group-containing vinyl monomer (B) and poly The total content of the oxyethylene chain-containing vinyl monomer (C) is preferably 40% by weight or more. The content of the fluorinated alkyl group-containing vinyl monomer (A) is more preferably 15 to 45% by weight, and most preferably 20 to 40% by weight. The total content of the amide group-containing vinyl monomer (B) and the polyoxyethylene chain-containing vinyl monomer (C) is particularly preferably 50% by weight or more.

  Other monomers that can be copolymerized can be used in combination with the monomers (i) that are the raw materials of the fluorocopolymer (I) used in the present invention. Examples of the monomer that can be used at this time include styrene, nucleus-substituted styrene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl pyridine, vinyl sulfonic acid, vinyl acetate and other fatty acid vinyls, and α, β-ethylenic monomers. As a saturated carboxylic acid, that is, a monovalent to divalent carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, or a derivative of α, β-ethylenically unsaturated carboxylic acid, 1 to 18 carbon atoms. (Meth) acrylic acid ester of a linear or branched alkyl group (hereinafter, this expression is a generic term for both acrylic acid alkyl ester and methacrylic acid alkyl ester), that is, methyl (meth) acrylic acid, Ethyl, propyl, butyl, octyl, 2-ethylhexyl, decyl, dodecyl, stearyl Esters, etc., and (meth) hydroxyalkyl esters having 1 to 18 carbon atoms of acrylic acid, i.e. 2-hydroxyethyl ester, hydroxypropyl ester, hydroxybutyl ester, and the like.

  Also, an aminoalkyl ester of (meth) acrylic acid having 1 to 18 carbon atoms, such as dimethylaminoethyl ester, diethylaminoethyl ester, diethylaminopropyl ester, etc .; (meth) acrylic acid containing 3 to 18 carbon atoms of ether oxygen Alkyl esters such as methoxyethyl ester, ethoxyethyl ester, methoxypropyl ester, methyl carbyl ester, ethyl carbyl ester, butyl carbyl ester, etc .; bridge-containing monomers such as dicyclopentanyloxylethyl (meth) acrylate, isobol Nyloxylethyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dimethyladamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate Rate, dicyclopentenyl (meth) acrylate, etc .; alkyl vinyl ethers having 1-18 carbon atoms in the alkyl group, such as methyl vinyl ether, propyl vinyl ether, dodecyl vinyl ether, etc .; glycidyl esters of (meth) acrylic acid, such as glycidyl methacrylate, Examples thereof include glycidyl acrylate and the like; various macromonomers such as styrene macromonomer manufactured by Sartomer, AA-6 and AN-6 manufactured by Toa Gosei Co., Ltd. and the like. Moreover, Kyoeisha Chemical Co., Ltd. product HOA-MS, HOA-MPL, HOA-MPE, HOA-HH, Toagosei Co., Ltd. product Aronix M-5300, M-5400, M-5500, M- 5600, M-5700 and the like.

  Further, vinyl monomers having a silicone chain, γ-methacryloxypropylmethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-acryloxypropylmethyltrimethoxysilane, γ -Silane coupling group-containing monomers such as acryloxypropylmethyldimethoxysilane and vinyltrimethoxysilane; monomers containing polar groups, particularly anionic groups and hydroxyl groups in the molecule, such as 2- (meth) acryloyloxyethyl Succinic acid, 2-acrylamido-2-methylpropanesulfonic acid, partially sulfonated styrene, mono (acryloyloxyethyl) acid phosphate, mono (methacryloxyethyl) acid phosphate, 2-hydroxyethyl (meth) acrylate And 2-hydroxypropyl (meth) acrylate.

  These monomers may be used alone or in combination of two or more.

  There is no limitation on the production method of the fluorinated copolymer (I), and various methods, that is, based on polymerization mechanisms such as radical polymerization method, cationic polymerization method, anion polymerization method, solution polymerization method, bulk polymerization method, suspension It can be produced by a polymerization method, further an emulsion polymerization method or the like.

  The structure of the fluorinated copolymer (I) is not particularly limited, and the molecular weight distribution is controlled by applying random, alternating, block copolymers, various living polymerization methods or polymer reactions based on the above polymerization mechanism. Blocks, grafts, star polymers and the like can be freely selected. Furthermore, after obtaining such a polymer, it is also possible to modify the polymer by various polymer reactions, methods using energy rays such as radiation, electron beam ultraviolet rays, or the like.

Among the above production methods, the radical polymerization method is industrially preferable because it is simple. In this case, various polymerization initiators can be used. For example, peroxides such as benzoyl peroxide and diacyl peroxide, azo compounds such as azobisisobutyronitrile and phenylazotriphenylmethane, Mn metal chelate compounds such as (acac) _{3 and the} like. In addition, chain transfer of a chain transfer agent such as lauryl mercaptan, 2-mercaptoethanol, ethylthioglycolic acid, octylthioglycolic acid or a coupling group-containing thiol compound such as γ-mercaptopropyltrimethoxysilane as necessary. It is also possible to use a combination of agents.

  The fluorine-based copolymer (I) can also be obtained by photopolymerization in the presence of a photosensitizer or photoinitiator, or by polymerization using radiation or heat as an energy source.

  The polymerization can be carried out in the presence or absence of a solvent, but the polymerization in the presence of a solvent is preferred because the workability is improved. As the solvent, alcohols such as ethanol, isopropyl alcohol, n-butanol, iso-butanol, tert-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl acetate, ethyl acetate, butyl acetate, Esters such as methyl lactate, ethyl lactate and butyl lactate; methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, butyl 2-oxypropionate, methyl 2-methoxypropionate, 2- Monocarboxylic acid esters such as ethyl methoxypropionate, propyl 2-methoxypropionate and butyl 2-methoxypropionate; polar solvents such as dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone; Ethers such as butyl, cellosolve, butyl cellosolve, butyl carbitol, ethyl cellosolve acetate; propylene glycols such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate; Its esters; halogen solvents such as trichloroethane and chloroform; ethers such as tetrahydrofuran and dioxane; aromatics such as benzene, toluene and xylene; fluorinated inert liquids such as perfluorooctane and perfluorotri-n-butylamine And the like.

  In the present invention, the fluorocopolymer (I) may be used alone or in combination of two or more.

  The polyimide resin (II) used in the present invention is a resin having a polyimide repeating unit, and any of thermosetting polyimide, thermoplastic polyimide, polyamideimide, polyetherimide and the like can be used. The structure other than the imide group is not particularly limited as long as the precursor polyamic acid is dissolved in an organic solvent, coated, and dried and cured by heating.

  The mixing ratio of the fluorine-based copolymer (I) and the polyimide-based resin (II) used in the present invention is not particularly limited. -From the point which is excellent in the balance of mechanical strength, it is preferable that a fluorocopolymer (I) is 0.1-10 weight part with respect to 100 weight part of polyimide-type resin (II), 0.3- More preferably, it is 5 parts by weight.

  The polyimide coating composition obtained in the present invention has excellent coating uniformity and excellent water and oil repellency, and is a coating agent for heat resistant films, chemical resistant paints, lubricating paints, heat resistant insulating paints, etc. Can be used for various industrial members.

  Next, examples and comparative examples for explaining the present invention in more detail are listed, but it is needless to say that the present invention is not limited to these examples.

Synthesis example 1
20 parts by weight of CH ₂ ═CH—CO—O—CH ₂ CH ₂ —C ₈ F ₁₇ as a fluorinated alkyl group-containing vinyl monomer in a glass flask equipped with a stirrer, a condenser and a thermometer, polyoxyethylene (EO) chain-containing vinyl monomer as M-230G 80 (NOF _{Corporation, CH 2 = C (CH 3} ) -CO-O- (EO) n -CH 3, n average 22) Part by weight, 233 parts by weight of methyl isobutyl ketone (hereinafter abbreviated as MIBK) were added, and 1 part by weight of perbutyl O (manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator was added under reflux, followed by refluxing for 12 hours for polymerization. Completed. MIBK was distilled off under vacuum to obtain a fluorinated copolymer (I-1).

Synthesis example 2
A glass flask equipped with a stirrer, a condenser, and a thermometer contains 30 parts by weight of CH ₂ ═CH—CO—O—CH ₂ CH ₂ —C ₈ F ₁₇ as a fluorinated alkyl group-containing vinyl monomer and an amide group 70 parts by weight of dimethylacrylamide (manufactured by Kojin Co., Ltd.) and 233 parts by weight of MIBK were added as vinyl monomers, and 1 part by weight of perbutyl O was added as a polymerization initiator under reflux, followed by refluxing for 12 hours for polymerization. Was completed. MIBK was distilled off under vacuum to obtain a fluorinated copolymer (I-2).

Synthesis example 3
Except for using 35 parts by weight of CH ₂ ═CH—CO—O—CH ₂ CH ₂ —C ₈ F ₁₇ and 65 parts by weight of N-vinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) as monomers, In the same manner as in Synthesis Example 2, a fluorinated copolymer (I-3) was obtained.

Synthesis example 4
Synthesis Example 2 except that 35 parts by weight of CH ₂ ═CH—CO—O—CH ₂ CH ₂ —C ₈ F ₁₇ , 35 parts by weight of M-230G and 30 parts by weight of dimethylacrylamide are used as monomers. In the same manner as above, a fluorinated copolymer (I-4) was obtained.

Synthesis example 5
_{CH 2 = CH-CO-O} -CH 2 CH 2 -C 8 F 17 15 parts by weight as a monomer, 75 parts by weight of dimethylacrylamide, SILAPLANE FM-0721 (manufactured by Chisso Corporation, one terminal methacryloxy group-modified A fluorine-based copolymer (I-5) was obtained in the same manner as in Synthesis Example 2 except that 10 parts by weight of (silicone) was used.

Synthesis Example 6
30 parts by weight of _{CH 2 = CH-CO-O} -CH 2 CH 2 -C 8 F 17 as a monomer, a polyoxypropylene chain-containing vinyl monomers PP-1000 70 weight (NOF Corporation) A fluorine-based copolymer (I-6) was obtained in the same manner as in Synthesis Example 2 except that a part of the copolymer was used.

Examples 1 to 6 and Comparative Examples 1 and 2
A solution was prepared by stirring and dissolving 100 parts by weight of polyamideimide resin Torlon AI-10 (manufactured by Solvay Advanced Polymers Co., Ltd.) in 400 parts by weight of dimethylacetamide at 50 ° C., and obtained in Synthesis Examples 1 to 6 Fluorine copolymers (I-1) to (I-6) were added to 100 parts by weight of the polyamideimide resin so as to have a concentration shown in Table 1 to prepare respective coating compositions. Using these coating compositions, the smoothness, transparency and water / oil repellency of the surface of the coating film were evaluated by the following methods. The evaluation results are shown in Table 1.

Comparative Example 3
Evaluation was performed in the same manner as in Comparative Example 2 except that a fluorine compound Fluowet OTN (manufactured by Clariant Co., Ltd.) represented by the following structural formula was used instead of the fluorine copolymer. The evaluation results are shown in Table 1.
_{C p F 2p + 1 C 2} H 4 O- (CH 2 CH 2 O) q -H
(In the formula, each of p and q is a distribution product of 6 to 10 and an average of 6.5.)

Evaluation Method 2 ml of the coating composition was dropped on a glass plate and leveled with an applicator having a thickness of 0.152 mm. This was put in a thermostatic bath, heated at 140 ° C. for 1 hour, then at 260 ° C. for 15 minutes, and further at 315 ° C. for 5 minutes, then taken out and allowed to cool to obtain a coating film. The smoothness and transparency of the coating surface were visually evaluated.

Smoothness ○: The coating film has no wrinkles or roughness X: The coating film has wrinkles or roughness

Transparency ○: There is no cloudiness through the coating film and glass, and transparency is good.
Δ: Some fogging through the coating film and glass, but there is no practical problem.
X: It is cloudy through a coating film and glass, or there is no transparency.

Water / oil repellency: measurement of contact angle Water, diiodomethane, and n-dodecane droplets were dropped on the surface of the coating film obtained above, and the contact angle was measured using an automatic contact angle meter CA-W150 (Kyowa Interface Science Co., Ltd.). And water / oil repellency was evaluated.

Footnotes in Table 1:
Impossibility of measurement: The coating film was opaque and the surface was rough (there was unevenness), and reliable data could not be obtained in the measurement of the contact angle.

  As is apparent from Table 1, the fluorinated alkyl group-containing vinyl monomer (A), the amide group-containing vinyl monomer (B) and / or the polyoxyethylene group-containing vinyl monomer (C) A coating composition comprising a fluorine-based copolymer (I) as an essential monomer and a polyimide-based resin (II) has excellent coating film smoothness and water / oil repellency. It has been found. In particular, it was found that the fluorocopolymer (I) containing the amide group-containing vinyl monomer (B) is excellent in compatibility with the polyimide resin (II) and has good transparency.

Claims (6)

Monomers (i) comprising a fluorinated alkyl group-containing vinyl monomer (A) and an amide group-containing vinyl monomer (B) and / or a polyoxyethylene chain-containing vinyl monomer (C) A polyimide-based coating composition comprising: a fluorine-based copolymer (I) obtained by polymerizing a polymer; and a polyimide-based resin (II). The content of the fluorinated alkyl group-containing vinyl monomer (A) in the monomers (i) is 5 to 50% by weight, and the amide group-containing vinyl monomer (B) and poly The composition for polyimide coating according to claim 1, wherein the total content of the oxyethylene chain-containing vinyl monomer (C) is 40% by weight or more. The polyimide coating composition according to claim 1, wherein the amide group-containing vinyl monomer (B) is dimethylacrylamide and / or N-vinylpyrrolidone. The fluorinated alkyl group-containing vinyl monomer (A) is represented by the following general formula (3)

[Wherein, R _f ′ is a C 1-20 perfluoroalkyl group, which may be linear or branched, and R ₁ is a hydrogen atom or a methyl group. ]
The polyimide coating composition according to claim 1, which is a compound represented by the formula: The polyimide coating composition according to claim 4, wherein R _f ′ in the general formula (3) has 4 to 12 carbon atoms. The polyimide coating composition according to any one of claims 1 to 5, wherein 0.1 to 10 parts by weight of the fluorocopolymer (I) is blended with 100 parts by weight of the polyimide resin (II).