JP5569027B2 - Carboxy group-containing polyimide resin solution, powder and production method thereof - Google Patents

Description

  The present invention relates to a method for producing a carboxy group-containing polyimide resin solution dissolved in a low-boiling organic solvent having a low environmental load. Moreover, this invention relates to the carboxy-group containing polyimide resin solution obtained by the said manufacturing method. Furthermore, the present invention relates to a carboxyl group-containing polyimide resin powder which is a useful intermediate for producing the resin solution and a method for producing the same. Furthermore, the present invention provides a curable resin composition containing the resin solution, and various heat resistant coating materials and electrical insulating materials, for example, interlayer insulating materials for printed wiring boards, build-up materials, semiconductor insulating materials, and the like, heat resistant adhesives It relates to a cured product useful in such fields.

  Polyimide resin has been rapidly used in engineering and plastics due to its excellent heat resistance, mechanical properties, sliding properties, etc. in recent years in electrical and electronic equipment applications, automotive parts applications, aerospace applications, office equipment applications, etc. Demand is increasing. In particular, in the field of electrical and electronic equipment, it is widely used for substrate films and the like from the viewpoint of heat resistance, reliability, mechanical properties, etc. that are higher than those of conventional epoxy resin curing systems. For this reason, in recent years, studies have been made on the use of such polyimide resins for interlayer insulating materials, adhesives, surface protective coating agents, various resists, and the like. In the development of electrical and electronic applications, a process such as painting is required, so a solution of the precursor polyamic acid is applied and a polyimide layer is formed by imidization by solvent evaporation and dehydration. . However, since polyamic acid has poor stability and high temperature is required for imidization, there are many problems such as limitations on usable substrates and applications, and difficulty in reproducing stable performance.

  On the other hand, studies using solvent-soluble polyimide resins are being conducted instead of such applications from polyamic acids. In general, since the solvent-soluble polyimide has a structure that has already been imidized and solubilized in an organic solvent, the above-described problems can be solved.

As such a solvent-soluble polyimide resin, an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule in an ether organic solvent, and a tricarboxylic acid anhydride (b1) And / or a carboxy group-containing amidoimide resin obtained by reacting tetracarboxylic anhydride (b2) is known (Patent Document 1). The cured coating film of the curable resin composition containing the carboxy group-containing amideimide resin dissolved in an ether solvent has high heat resistance, excellent mechanical strength (high breaking strength, high breaking elongation), and PCT resistance. It has the effect of excellent solder heat resistance.
However, the carboxy group-containing amidoimide resin is a polar solvent having a boiling point higher than the reaction temperature of the imidization reaction (“high boiling point organic solvent”) in terms of the temperature at which the imidization reaction proceeds (generally 140 to 160 ° C.). ”, And there is a problem of residual solvent and the like in the process of painting-drying-curing. For example, if the drying process is inadequate and the organic solvent remains, film defects such as “waki”, “blowing”, and “peeling” will occur in the cured coating. And was subject to various industrial restrictions.

  Therefore, the present inventors examined a resin solution dissolved in an organic solvent having a boiling point lower than the reaction temperature of the imidization reaction (sometimes referred to as a “low boiling point organic solvent”). However, the carboxy group-containing polyimide resin has low dilution stability, and as a result, even if the solvent is simply replaced from a high-boiling organic solvent to a low-boiling organic solvent, the resin dissolved at the time of dilution may precipitate. There is a problem that a step of removing the precipitate is necessary, the resin concentration in the resin solution cannot be controlled, and a predetermined physical property value cannot be obtained. In addition, various modifications to the carboxy group-containing polyimide resin to improve the solubility also reduce the various physical properties such as heat resistance (Tg, solder heat resistance) and linear expansion coefficient of the obtained cured product. , Couldn't solve the problem.

JP 2001-316469 A

  Therefore, the problem to be solved by the present invention is to provide a carboxy group-containing polyimide resin solution dissolved in a low boiling point organic solvent and a method for producing the same. Moreover, this invention makes it a subject to provide the carboxy-group containing polyimide resin excellent in the dilution stability to a low boiling-point organic solvent, and its manufacturing method. Furthermore, the present invention has few coating film defects such as “waki”, “blowing”, and “peeling” even in a low temperature and short drying process, and various physical properties such as heat resistance (Tg, solder heat resistance) and linear expansion coefficient. It is an object of the present invention to provide a curable resin composition and a cured product containing a carboxy group-containing polyimide resin which is excellent in the above.

  As a result of intensive studies to solve the above problems, the present inventors have significantly improved the physical shape of the resin, specifically, the stability of dilution into a low-boiling organic solvent by pulverizing the resin, As a result, it has been found that a carboxy group-containing polyimide resin solution dissolved in a low-boiling organic solvent can be provided, and has solved the above problems.

That is, the present invention relates to an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride ( b2), a method for producing a carboxy group-containing polyimide resin solution comprising a carboxy group-containing polyimide resin obtained by reacting with an organic solvent (B),
(1) In an organic solvent (A) or in the absence of a solvent, an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, and a tricarboxylic acid anhydride (b1) And / or a synthesis step of reacting with tetracarboxylic anhydride (b2) to obtain a carboxy group-containing polyimide resin,
(2) A granulating step of volatilizing the organic solvent (A) while spraying the organic solvent (A) containing the carboxy group-containing polyimide resin to obtain a powder of the carboxy group-containing polyimide resin;
(3) Provided is a method for producing a carboxy group-containing polyimide resin solution, comprising a solvent dissolving step of dissolving the powder of the carboxy group-containing polyimide resin in an organic solvent (B).
The present invention also relates to an aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride ( b2), a carboxy group-containing polyimide resin solution containing a carboxy group-containing polyimide resin obtained by reacting with an organic solvent, wherein the proportion of the organic solvent having a boiling point of 130 ° C. or lower in the total organic solvent is 99% by weight or more. A carboxy-containing polyimide resin solution is provided.
The present invention also relates to an aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride ( A carboxy group-containing polyimide resin powder obtained by reacting with b2) is provided.
Further, the present invention is a method for producing the carboxy group-containing polyimide resin powder,
(1) In an organic solvent (A), an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or tetra A synthesis step of reacting the carboxylic acid anhydride (b2) to obtain a carboxy group-containing polyimide resin;
(2) A granulation step of obtaining a carboxy group-containing polyimide resin powder by volatilizing the solvent while spraying the organic solvent (A) containing the carboxy group-containing polyimide resin. A method for producing a resin powder is provided.
Moreover, this invention provides the manufacturing method of the carboxy group containing polyimide resin solution characterized by having the solvent melt | dissolution process which dissolves the said carboxy group containing polyimide resin powder in the organic solvent (B).
The present invention also provides a curable resin composition comprising a carboxy group-containing polyimide resin solution obtained by the production method and a curable resin component.
Moreover, this invention provides the hardened | cured material formed by hardening | curing the said curable resin composition.

The present invention can provide a carboxy group-containing polyimide resin solution dissolved in a low-boiling organic solvent and a method for producing the same. In addition, the present invention suppresses resin precipitation even when diluted with a low-boiling organic solvent without reducing various physical properties such as heat resistance (Tg, solder heat resistance) and linear expansion coefficient of the obtained cured product. Possible production intermediates and methods for their production can be provided. Furthermore, the present invention has few coating film defects such as “waki”, “blowing”, and “peeling” even in a low temperature and short drying process, and various physical properties such as heat resistance (Tg, solder heat resistance) and linear expansion coefficient. A carboxy group-containing polyimide resin-containing curable resin composition and a cured product can be provided.
When curing as described above, a low-temperature, short-time drying process is sufficient, so that the environmental burden can be reduced. Moreover, since the manufacturing method of the resin solution of this invention can be manufactured continuously, it is industrially advantageous. Moreover, since the organic solvent used for the imidation reaction can be recovered and reused, the environmental load can be further reduced.

It is the schematic of the manufacturing apparatus of the polyimide resin powder using the spray drying used for this invention. It is an optical microscope photograph of the carboxyl group-containing polyimide resin powder of the present invention.

-Production method of carboxy group-containing polyimide resin solution The carboxy group-containing polyimide resin solution of the present invention comprises an aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, and a tricarboxylic acid. In a method for producing a carboxy group-containing polyimide resin solution obtained by dissolving a carboxy group-containing polyimide resin powder obtained by reacting an acid anhydride (b1) and / or a tetracarboxylic acid anhydride (b2) in an organic solvent. There,
(1) In an organic solvent (A), an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or tetra A synthesis step of obtaining a carboxy group-containing polyimide resin by reacting with a carboxylic acid anhydride (b2);
(2) A granulating step of volatilizing the organic solvent (A) while spraying the organic solvent (A) containing the carboxy group-containing polyimide resin to obtain a powder of the carboxy group-containing polyimide resin;
(3) A solvent dissolving step of dissolving the carboxy group-containing polyimide resin powder in an organic solvent (B). Hereinafter, each process is explained in full detail.

(1) Synthesis step The first step is an organic solvent (A) or a solvent-free aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, This is a synthesis step in which a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride (b2) is imidized to obtain a carboxy group-containing polyimide resin.

In the imidization reaction, one or more kinds of isocyanate compound (a) and one or more kinds of tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) are mixed in a solvent or in the absence of a solvent. The temperature is preferably increased while stirring. The reaction temperature is preferably 50 ° C. to 250 ° C., more preferably 70 ° C. to 180 ° C., and industrially particularly preferably 140 to 160 ° C. in which the imidization rate (reaction rate) increases. When the reaction temperature is low, the reaction rate tends to be slow, and when the reaction temperature is high, side reactions and decomposition tend to occur. While the reaction is accompanied by decarboxylation, the acid anhydride group and the isocyanate group form an imide group. The progress of the reaction can be followed by an analytical means such as an infrared vector, acid value, or isocyanate group quantification. The infrared spectrum, 2270 cm ^-1 which is the characteristic absorption of an isocyanate group was reduced as the reaction further acid anhydride group is reduced with a characteristic absorption at 1860 cm ^-1 and 850 cm ^-1. On the other hand, the absorption of imide groups increases at 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ⁻¹ . The reaction may be terminated by lowering the temperature while confirming the target acid value, viscosity, molecular weight and the like. However, it is more preferable to continue the reaction until the isocyanate group disappears from the standpoint of stability over time. In addition, during the reaction or after the reaction, a catalyst, an antioxidant, a surfactant, other solvents, and the like may be added as long as the physical properties of the synthesized resin are not impaired. In the present invention, the acid anhydride group refers to a —CO—O—CO— group obtained by intramolecular dehydration condensation of two molecules of carboxylic acid.

  In the carboxy group-containing imide resin used in the present invention, the aliphatic isocyanate compound having two or more isocyanate groups in the molecule and the alicyclic socyanate compound (a) are essential materials for improving the solubility in general-purpose solvents. Yes, and preferably 70% by weight or more of the total isocyanate raw material. In consideration of crystallization over time during the reaction, it is particularly preferably 80% by weight or more of the total isocyanate raw material.

  Examples of the aliphatic isocyanate compound and alicyclic isocyanate compound include, as a bifunctional isocyanate monomer (a1), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylene diisocyanate. Aliphatic and alicyclic isocyanates such as (HXDI), norbornylene diisocyanate (NBDI), and lysine diisocyanate. Further, isocyanurated products (polyisocyanate, (a2)) such as nurate of diisocyanates such as IPDI3N (isoisocyanurate type triisocyanate of isophorone diisocyanate), HDI3N (isocyanurate type triisocyanate of hexamethylene diisocyanate), HXDI3N ( Hydrogenated xylene diisocyanate isocyanurate type triisocyanate), NBDI3N (norbornane diisocyanate isocyanurate type triisocyanate), and the like. Furthermore, the buret body of the said isocyanate compound and the adduct body obtained by the urethanation reaction of the said isocyanate compound and various polyols can also be used. In particular, in terms of heat resistance, thermal properties such as Tg, and solvent solubility, the combined use of the bifunctional isocyanate monomer (a1) and the isocyanurate type polyisocyanate (a2), or the sole use of the isocyanurate type polyisocyanate (a2) is possible. preferable.

  Aromatic isocyanates (a3) can be used in combination as long as the non-crystallinity of the system is not impaired, but the amount is preferably 30% or less, particularly preferably 20% or less, based on the total isocyanate compound. That is, “W-NCO” (total isocyanate compound (weight)) = W (a1) + W (a2) + W (a3), where W (a1), W (a2), and W (a3) are (a1) , (A2) and (a3), and the use range (weight ratio) of the aromatic isocyanate is preferably W (a3) / {W (al) + W (a2) + W (a3)} ≦ 0. 3 and particularly preferably W (a3) / {W (a1) + W (a2) + W (a3)} ≦ 0.2. Representative examples of such aromatic isocyanates include p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4, 4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 3,3'-diethyldiphenyl-4,4'-diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, naphthalene diisocyanate, etc. It is done. Similarly, polyisocyanate raw materials such as one or more burettes or nurates of such isocyanate monomers can be used, and adducts obtained by urethanization reaction of the isocyanate compound and various polyols can also be used.

  In the present invention, by directly forming an imide bond from the above-mentioned isocyanate compound and a specific acid anhydride, a resin having good reproducibility and good solubility without passing through a polyamic acid intermediate having a problem in stability or the like. The system can be synthesized.

The tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) used in the present invention is preferably an aromatic acid anhydride compound. Specifically, tricarboxylic acid anhydrides such as trimellitic anhydride and naphthalene-1,2,4-tricarboxylic acid anhydride; pyromellitic dianhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic acid Acid dianhydride, diphenyl ether-3,3 ', 4,4'-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, biphenyl-3,3'4,4 '-Tetracarboxylic dianhydride, biphenyl-2,2'3,3'-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2, 4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8 -Dimethyl-1,2,3,5 6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloro Naphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, fetentylene-1,3 9,10-tetracarboxylic dianhydride, berylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-di Carboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1 bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2- Bis (2,3-dicarbox Cyphenyl) propane dianhydride, 2,3-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) ) Tetracarboxylic acid anhydrides having an aromatic organic group in the molecule, such as ether dianhydride, may be used, and one or more of these may be used. Further, a tricarboxylic acid anhydride and a tetracarboxylic acid anhydride may be mixed and used. In some cases, bifunctional dicarboxylic acid compounds such as adipic acid, sebacic acid, phthalic acid, fumaric acid, maleic acid and acid anhydrides thereof may be used in combination.
In the imidization reaction between the tricarboxylic acid anhydride and the isocyanate compound, a polyimide resin having an amide bond and an imide bond is generated. Therefore, the polyimide resin of the present invention includes a polyamideimide resin having an amide bond and an imide bond.

  As said organic solvent (A), if it is a polar solvent with a boiling point higher than the reaction temperature of imidation reaction, a well-known and usual thing can be used, In balance with the suitable temperature range of reaction temperature of imidation reaction, It is preferable to use an organic solvent having a boiling point of 70 ° C. or higher, and it is more preferable to use an organic solvent having a boiling point of 140 ° C. or higher. As such an organic solvent, either a polar solvent containing either a nitrogen atom or a sulfur atom, or a polar solvent containing neither a nitrogen atom nor a sulfur atom can be used. However, if there is a polar solvent containing either a nitrogen atom or a sulfur atom, problems in the working environment are likely to occur, and such an isocyanate compound and a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride (b2) ), A polar solvent containing neither a nitrogen atom nor a sulfur atom is preferred.

Examples of the polar solvent containing either a nitrogen atom or a sulfur atom in the present invention include N-methyl-2-pyrrolidone (boiling point 202 ° C.), dimethylacetamide (boiling point 165 ° C.), and dimethylformamide (153 ° C.). Amides, sulfur such as dimethyl sulfoxide (boiling point 189 ° C), sulfolane (boiling point 285 ° C), nitros such as nitromethane (101 ° C), nitroethane, acetonitrile (boiling point 82 ° C), propionitrile (boiling point 97 ° C), etc. Nitriles, tetramethylurea (boiling point 177 ° C.) and the like.
Among these, amides such as N-methyl-2-pyrrolidone (boiling point 202 ° C.), dimethylacetamide (boiling point 165 ° C.), dimethylformamide (153 ° C.), dimethyl sulfoxide ( It is preferable to use a solvent such as sulfur (boiling point 189 ° C.), sulfolane (boiling point 285 ° C.), or tetramethylurea (boiling point 177 ° C.).

  In the present invention, examples of the polar solvent containing neither a nitrogen atom nor a sulfur atom include a protic solvent and an aprotic solvent, and among these, an aprotic solvent is more preferable. For example, a cresol solvent is a phenolic solvent having protons, but is somewhat unfavorable in terms of the environment, and easily reacts with an isocyanate compound to hinder molecular growth. In addition, the cresol solvent easily reacts with an isocyanate group to easily become a blocking agent. Therefore, it is difficult to obtain good physical properties by reacting with other curing components (for example, epoxy resin) during thermal curing. Furthermore, if the blocking agent is removed, it is likely to cause contamination of the equipment used and other materials. Also, alcohol solvents are not preferred because they react with isocyanates or acid anhydrides. Examples of the aprotic solvent include ether-based, ester-based, and ketone-based solvents having no hydroxyl group, and among these, ether-based solvents having no hydroxyl group are particularly preferable.

In the present invention, the polar solvent containing neither a nitrogen atom nor a sulfur atom is more preferably an ether solvent. The ether solvent has a weak polarity and has an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or Alternatively, it provides an excellent reaction field in the reaction with the tetracarboxylic acid anhydride (b2). As such ether solvents, known and commonly used solvents can be used. For example, cyclic ethers such as tetrahydrofuran (boiling point 66 ° C.), ethylene glycol dimethyl ether (boiling point 82 ° C.), ethylene glycol diethyl ether, ethylene glycol dibutyl ether ( Ethylene glycol dialkyl ethers such as boiling point 121.4 ° C; diethylene glycol dimethyl ether (boiling point 162 ° C), diethylene glycol diethyl ether (boiling point 189 ° C), diethylene glycol dibutyl ether (boiling point 256 ° C), triethylene glycol dimethyl ether (boiling point 216 ° C), etc. Polyethylene glycol dialkyl ethers; ethylene glycol monoalkyl such as ethylene glycol monomethyl ether acetate (boiling point 145 ° C.) Ether acetates; polyethylene glycol monoalkyl ether acetates such as diethylene glycol monoethyl ether acetate (boiling point 217.4 ° C.) and diethylene glycol monobutyl ether acetate (boiling point 246.8 ° C.); propylene glycol dialkyl such as propylene glycol dimethyl ether (boiling point 97 ° C.) Ethers; polypropylene glycol dialkyl ethers such as dipropylene glycol dimethyl ether (boiling point 171 ° C.) tripropylene glycol dimethyl ether (boiling point 215 ° C.); propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate (boiling point 146.0 ° C.) ; Polypropylene glycol monoalkyl ether acetates; Dialkyl ethers of copolymerized polyether glycols such as low molecular weight ethylene-propylene copolymers, monoacetate monoalkyl ethers of copolymerized polyether glycols; or alkyl esters of such polyether glycols; monoalkyls of polyether glycols And ester monoalkyl ethers.
Of these, diethylene glycol dimethyl ether (boiling point 162 ° C.), diethylene glycol diethyl ether (boiling point 189 ° C.), diethylene glycol dibutyl ether (boiling point 256 ° C.), triethylene glycol dimethyl ether (boiling point 216 ° C.) in that the imidization reaction can be carried out at 140 ° C. or higher. Polyethylene glycol dialkyl ethers such as ethylene glycol monomethyl ether acetate (boiling point 145 ° C.) and the like; diethylene glycol monoethyl ether acetate (boiling point 217.4 ° C.), diethylene glycol monobutyl ether acetate (boiling point 246.8) ° C) polyethylene glycol monoalkyl ether acetates, dipropylene glycol dimethyl ether Polypropylene glycol dialkyl ethers (boiling point 171 ° C.); propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate (boiling point 146.0 ° C.); polypropylene glycol monoalkyl ether acetates or low molecular weight ethylene-propylene copolymers Dialkyl ethers of copolymerized polyether glycols such as polymers, monoacetate monoalkyl ethers of copolymerized polyether glycols; or alkyl esters of such polyether glycols; monoalkyl ester monoalkyl ethers of polyether glycols, etc. Among them, those having a boiling point of 140 ° C. or higher are preferred.

  As the ketone organic solvent, known and commonly used solvents can be used, and examples thereof include ketones such as cyclohexanone (boiling point 155.7 ° C.) and methyl ethyl ketone (boiling point 79.5 ° C.). Among these, cyclohexanone (boiling point: 155.7 ° C.) is preferable because imidization reaction can be performed at 140 ° C. or higher.

  As the ester organic solvent, known and commonly used solvents can be used. For example, ethyl acetate (boiling point 78 ° C.), propyl acetate (boiling point 102 ° C.), butyl acetate (boiling point 126 ° C.), isobutyl acetate (boiling point 118 ° C.) And esters such as pentyl acetate (boiling point 148 ° C.), isopentyl acetate (boiling point 143 ° C.), methyl propionate (boiling point 78 ° C.), ethyl propionate (boiling point 99 ° C.), and butyl propionate (boiling point 145 ° C.). . Among these, pentyl acetate (boiling point 148 ° C.), isopentyl acetate (boiling point 143 ° C.), and butyl propionate (boiling point 145 ° C.) are preferable in that the imidization reaction can be performed at 140 ° C. or higher.

The aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule is reacted with the tricarboxylic acid anhydride (b1) and / or the tetracarboxylic acid anhydride (b2). In this case, the number of moles (N) of the isocyanate group of the aliphatic isocyanate compound and / or the alicyclic isocyanate compound (a) and the carboxy group of the tricarboxylic acid anhydride (b1) and / or the tetracarboxylic acid anhydride (b2). The number of moles (M1) and the number of moles of acid anhydride groups (M2) preferably satisfy the following formula.
3> ((M1) + (M2)) / (N))> 1.1. Particularly preferably, 2> ((M1) + (M2)) / (N))> 1.2. At this time, if the sum of the number of moles of carboxy groups (M1) and the number of moles of acid anhydride groups (M2) is larger than the number of moles of isocyanate groups (N), the polarity in the reaction system increases. The reaction proceeds to lubrication. When the above ratio is deviated, for example, 1.1 or less, the isocyanate group remains and the stability and the like tend to be slightly deteriorated. In the case of 3 or more, the acid anhydride-containing compound remains and tends to be in a state of separation such as recrystallization.

  The blending ratio ((b2) / (b1)) of the tetracarboxylic anhydride (b2) and the tricarboxylic anhydride (b1) is preferably a ratio of 0-2. When the blending ratio of the tetracarboxylic acid anhydride (b2) exceeds this range, the concentration of the imide bond increases and the solvent solubility and non-crystallinity may not always be sufficient.

  When the aliphatic isocyanate compound having two or more isocyanate groups in the molecule and / or the alicyclic isocyanate compound (a) is composed of a composition comprising the isocyanurate type polyisocyanate (a2), it is further excellent. It is preferable because it exhibits cured properties and solubility performance. Specifically, the weight ratio between the diisocyanate monomer (a1) and the isocyanurate type polyisocyanate (a2) is excellent when W (a1) / W (a2) is 0 to 0.5, particularly 0 to 0.3. It is preferable because of its performance. When W (a1) / W (a2) = 0, it means that all isocyanate components are isocyanurate type polyisocyanate (a2), and the tetracarboxylic anhydride (b2) and tricarboxylic anhydride (b1 ) In the range of 0 to 1 ((b2) / (b1)).

Examples of the carboxy group-containing polyimide resin obtained by the method of the present invention include the following.
(Example 1) Imide resin represented by (Formula 1) obtained by reaction of aliphatic and alicyclic diisocyanates and aromatic tricarboxylic acid anhydride (b1).

  (Ra represents a residue of a divalent aliphatic or alicyclic diisocyanate. N is a repeating unit of 0 to 30. Rb is represented by the following structural formula (Formula 2) or (Formula 3). ).

(R ₂ is an aromatic tricarboxylic acid residue that may have a substituent having 6 to 20 carbon atoms.) Rc is a structural unit represented by the following structural formula (formula 4).

(R ₂ is the same as above.))

  (Example 2) An imide resin represented by (Formula 5) when the aromatic tricarboxylic acid anhydride (b1) and the tetracarboxylic acid anhydride (b2) are used in combination in Example 1.

  (Rb ′ is a structural unit represented by the above (formula 2), (formula 3), or the following (formula 6),

(R ₃ represents an aromatic tetracarboxylic anhydride residue that may have a substituent having 6 to 20 carbon atoms.) Rc ′ is the above (Formula 4) or the following (Formula 7). , (Structural unit 8)

(R ₃ is the same as above.) Ra and n are the same as above. )

  (Example 3) An imide resin represented by (formula 9) obtained by reaction of an aliphatic or alicyclic isocyanurate type triisocyanate and an aromatic tricarboxylic acid anhydride (b1).

  (Rd is a trivalent organic group represented by the following (formula 10),

  (Ra is the same as above.) Rb, Rc, and n are the same as above. )

  (Example 4) It is represented by (Formula 11) obtained by reaction of an aliphatic or alicyclic isocyanurate type triisocyanate with an aromatic tricarboxylic acid anhydride (b1) and a tetracarboxylic acid anhydride (b2). Imide resin.

  (Rb ', Rc' and Rd are the same as described above.)

  Further, when a diisocyanate compound and an isocyanurate type triisocyanate are used in combination, the compound has a composite structure of the above (formula 1) and (formula 9), and the terminal structure thereof is Rc- in (formula 1). The structure of (Rc) 2-Rd- in Ra- and (Formula 9) is present at the molecular end. Further, the structure of the main chain skeleton includes a unit of -Ra-Rb- in (Formula 1) and a structure of -Rd (Rc) -Rb- in <Formula 9>. Furthermore, it is possible to use an aromatic isocyanate compound in combination so as not to impair the non-crystallinity and solubility. In that case, Ra in the above formula partially becomes a divalent aromatic group.

  The acid value of the carboxy group-containing polyimide resin of the present invention is preferably 60 to 200 KOHmg / g, and particularly preferably 80 to 180 KOHmg / g. If it is 60-200 KOHmg / g, the performance which was excellent as hardened | cured material property will be demonstrated.

The molecular weight of the carboxy group-containing polyimide resin of the present invention is preferably a number average molecular weight of 1,000 to 20,000, preferably 1,000 to 8,000, in that a cured product having excellent solubility in a solvent and excellent mechanical strength is obtained. More preferred. The molecular weight can be measured by gel permeation chromatography (GPC) or quantitative analysis of the terminal functional group amount.
In the present invention, the number average molecular weight was determined using GPC under the following conditions.
Measuring device: HLC-8120GPC, UV8020 manufactured by Tosoh Corporation
Column: TFKguardcolumnHXL-L, TFKgel (G1000HXL, G2000HXL, G3000HXL, G4000HXL) manufactured by Tosoh Corporation
Detector: RI (differential refractometer) and UV (254 nm)
Measurement conditions: Column temperature 40 ° C
Solvent THF
Flux 1.0ml / min
Standard: Calibration curve prepared with polystyrene standard sample: 0.1% by weight THF solution in terms of resin solid content filtered through microfilter (injection amount: 200 μl)

(2) Granulation step In the second step, the organic solvent (A) is volatilized by spraying the resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin obtained in the above step. This is a granulation step for obtaining a powder of a group-containing polyimide resin. In the synthesis step, when synthesized in the absence of a solvent, the resin is once dissolved in the organic solvent (A) to obtain a resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin, which is subjected to the granulation step.

  As the method for volatilizing the organic solvent (A) while spraying the resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin in the granulation step, various known and conventional methods can be used. For example, a spray dryer, a thin film evaporator, a kneader and the like can be mentioned, and a spray drying method using a spray dryer or the like is preferable.

As the spray dryer used for spray drying, a type having a disk atomizer or a two-fluid nozzle as a spraying device can be preferably used. As spraying conditions of the spray dryer, in the case of a disk-type atomizer, the rotational speed is preferably 25,000 to 30,000 rpm, and the flow rate is preferably 30 to 70 ml / min. In the case of a two-fluid nozzle, the resin solution preferably has a viscosity of 10 to 3000 mPa · s and a flow rate of 0.1 to 5 kg / h. Moreover, it is preferable to heat the temperature of a resin solution in the range of 30-130 degreeC.
Examples of drying conditions for the spray dryer include a temperature range of 50 to 350 ° C. Examples of such a spray dryer device include a spray dryer FGA, a spray dryer CL (manufactured by Okawara Chemical Co., Ltd.), and the like.

  The content of the organic solvent (A) contained in the carboxy group-containing polyimide resin obtained under the above granulation conditions is preferably 0 to 20% by weight and 0 to 10% by weight. If the content is high, it is preferable to provide a separate drying step to remove the organic solvent (A) in the particles to completely remove the organic solvent.

  When the unidirectional diameter of the carboxy group-containing polyimide resin powder obtained by the granulation step was measured with an optical microscope (“DIGITAL MICROSCOPE VHX” manufactured by Keyence Corporation), the particle size was 0.01 to 2000 μm, preferably 1. It was confirmed that 90% or more of any one of ˜100 μm fibrous, spherical, elliptical, and amorphous particles was contained.

(3) Re-dissolution step The following third step is a dissolution step in which the carboxy group-containing polyimide resin powder obtained in the previous step is dissolved in the organic solvent (B).

As said organic solvent (B), although the reaction temperature of imidation reaction changes with polymer compositions, the organic solvent whose boiling point is lower than the reaction temperature of imidation reaction can be mentioned. For example, as the organic solvent (B) having a boiling point lower than the reaction temperature of the imidization reaction, ketones such as methyl ethyl ketone (boiling point 79.5 ° C.), methyl isobutyl ketone (boiling point 116 ° C.), acetone (boiling point 56.5 ° C.), acetic acid Esters such as ethyl (boiling point 77.1 ° C), butyl acetate (boiling point 126 ° C), ethers such as tetrahydrofuran (boiling point 66 ° C), dioxane (boiling point 101 ° C), methanol (boiling point 64.7 ° C), ethanol ( Boiling point: 78.4 ° C), alcohols such as isopropyl alcohol (boiling point: 82.4 ° C), butanol (boiling point: 117 ° C), aliphatic organic solvents such as hexane (boiling point: 69 ° C), benzene (boiling point: 80.1 ° C) , Aromatic organic solvents such as toluene (boiling point 110.6 ° C.), and one or a mixture of two or more of these are preferred. It can be appropriately selected lower solvent than the reaction temperature of the reaction.
Among these, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and tetrahydrofuran can be mentioned as preferable organic solvents.

As said organic solvent (B), it is possible to use the organic solvent which is not suitable for using as a synthetic solvent (organic solvent (A)) of imidation reaction. For example, cyclohexanone, dimethylformamide, dimethylacetamide are organic solvents that may be unsuitable for use as the organic solvent (A) because the organic solvent undergoes thermal decomposition near the imidation reaction temperature and produces by-products. N methylpyrrolidone and the like.

  In the present invention, “dilution stability” means the ease of entry of the organic solvent into the resin, and refers to the stability of the dispersion when the resin is diluted with the organic solvent. The carboxy group-containing polyimide resin powder of the present invention is excellent in dilution stability. Surprisingly, even when diluted with the low-boiling organic solvent at room temperature (18 to 35 ° C.), the resin does not precipitate, and There is no change in the transparency (turbidity) of the solution, and the fluidity is excellent. The temperature of the resin solution at the time of dilution can be at room temperature as described above, but can be generally within the range from room temperature to the boiling point of the organic solvent used for dilution, and the higher the temperature, the shorter the re-dissolution step. Can be terminated.

-Carboxy group-containing polyimide resin solution The carboxy-containing polyimide resin solution of the present invention is produced by a production method having the first (synthesis step), second (granulation step), and third (remelting step). It contains a containing polyimide resin and an organic solvent (B) having a boiling point of 130 ° C. or lower. The proportion of the organic solvent (B) having a boiling point of 130 ° C. or less in the total organic solvent is 99% by weight or more, preferably 99.5% by weight or more, more preferably 99.9% by weight or more, and most preferably 100% by weight. (Below the detection limit of organic solvents other than organic solvent (B)).
The content of the carboxy group-containing polyimide resin with respect to the carboxy group-containing polyimide resin solution is 0.1 to 90% by weight, preferably 10 to 80% by weight, and more preferably 20 to 70% by weight.

  In addition, since the carboxy group-containing polyimide resin powder of the present invention has excellent dilution stability even with respect to the organic solvent (A), the carboxy group-containing polyimide resin powder once manufactured is temporarily treated with the organic solvent (A It is also possible to prepare a resin solution containing the organic solvent (A) and the carboxy group-containing polyimide resin, and store it. In this case, the carboxy group-containing polyimide resin solution of the present invention containing the organic solvent (B) and the carboxy group-containing polyimide resin can be produced by going through the granulation step and the remelting step again.

-Curable resin composition The curable resin composition of this invention contains the said carboxy-group-containing amideimide resin solution (C) and curable resin component (D). Examples of the curable resin component (D) include known and commonly used ones, and are not particularly limited. For example, epoxy resin (D1), melamine resin (D2), isocyanate compound (D3), silicate (D4) ), Alkoxysilane compound (D5), etc., among which epoxy resin (D1) is preferred. The curable resin composition comprising the component (C) and the component (D) can be applied to an object to be coated, cast, etc., dried, and further cured by heating.
The drying temperature is 30 to 150 ° C., and the drying time is 1 to 120 (minutes). In particular, drying at a low temperature and a short time of 30 to 60 ° C. and 1 to 5 (min) may be used. Compared to conventional resin solutions dissolved in high-boiling organic solvents, the organic solvent can be removed by drying at a low temperature and for a short time. Film defects can be reduced.
The curing temperature is preferably 80 ° C to 300 ° C, particularly 120 ° C to 250 ° C. Further, step curing at various temperatures may be performed. Alternatively, a sheet-like or film-like composition semi-cured at a temperature of about 50 ° C. to 170 ° C. may be stored and treated at the above-described curing temperature when necessary. The curing reaction between the component (C) and the component (D) is basically a condensation reaction between a carboxy group and an epoxy group or an alkoxy group, and the type and blending ratio of the component (C) and the component (D), By selecting curing conditions and the like, a curable resin composition having excellent physical properties and the like can be obtained.

  Here, as said epoxy resin (D1), if it contains the epoxy compound which has a 2 or more epoxy group in a molecule | numerator, a well-known and usual epoxy resin can be mentioned. It is particularly preferable that the epoxy compound component has a softening point of 50 ° C or higher. If a softening point is 50 degreeC or more, the physical property of the curable resin composition of this invention will become more excellent.

  Examples of such epoxy resins include bisphenol A type epoxy, bisphenol S type epoxy, bisphenol F type epoxy, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and various diacids obtained by reacting dicyclopentadiene with various phenols. Epoxidized cyclopentadiene-modified phenolic resin, epoxidized 2,2 ′, 6,6′-tetramethylbiphenol, epoxidized 4,4′-methylenebis (2,6-dimethylphenol), naphthol, binaphthol, naphthol, Examples thereof include epoxy derived from a naphthalene skeleton such as a novolak modification of binaphthol, and an aromatic epoxy resin such as an epoxy resin obtained by epoxidizing a phenol resin having a fluorene skeleton. In addition, aliphatic epoxy resins such as neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4- Epoxy bicyclohexyl) An alicyclic epoxy resin obtained by oxidizing cyclohexene such as adipate, and a heterocyclic ring-containing epoxy resin such as triglycidyl isocyanurate can also be used.

  In addition, an epoxy group-containing polymerization resin obtained by polymerizing an unsaturated group of an epoxy compound having a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group, and other monomers having a polymerizable unsaturated bond Copolymers with can also be used.

  Examples of the compound having both (meth) acryloyl group and epoxy group include glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate glycidyl ether, hydroxypropyl (meth) acrylate glycidyl ether, 4-hydroxydibutyl (meth) acrylate glycidyl ether. , 6-hydroxyhexyl (meth) acrylate glycidyl ether, 5-hydroxy-3-methylpentyl (meth) acrylate glycidyl ether, (meth) acrylic acid-3,4-epoxycyclohexyl, lactone modified (meth) acrylic acid-3, 4-epoxycyclohexyl, vinylcyclohexene oxide and the like can be mentioned.

  The blending amount of the polyimide resin and the epoxy resin used in the present invention can be used in a ratio of (polyimide resin) / (epoxy resin) of 1/100 to 50/1 as a weight ratio of the resin, and more preferably Is from 1/10 to 20/1.

  The above component (C) and component (D1) can be freely blended in accordance with various target physical properties, but they have thermal physical properties such as glass transition temperature (hereinafter simply referred to as Tg), water resistance, and the like. In terms of properties and mechanical properties, the number of moles n (COOH) of the carboxy group of the component (C) and the number of moles n (EPOXY) of the epoxy group of the component (D1) are 4> n (EPOXY) / n (COOH) It is preferable to blend in the range of> 0.8. When n (EPOXY) / n (COOH) is 4 or more, it is difficult to obtain Tg as a characteristic of the cured coating film, and when it is 0.8 or less, there may be a problem with water resistance.

  When heat-curing, an epoxy-carboxylic acid-based curing catalyst or the like may be used in combination. Such epoxy-carboxylic acid curing catalysts include primary to tertiary amines for promoting the reaction, quaternary ammonium salts, nitrogen compounds such as dicyandiamide, imidazole compounds, and TPP (triphenylphosphine). ), Known epoxy curing accelerators such as phosphine compounds such as alkyl-substituted trialkyl phonylphosphine and derivatives thereof, phosphophonium salts thereof, dialkylureas, carboxylic acids, phenols, or methylol group-containing compounds. Etc., and a small amount of these can be used in combination.

  Examples of the melamine resin (D2) include alkoxylated melamine resins. As the alkoxylated melamine resin, it is possible to use an alkoxylated melamine resin obtained by reacting a part or all of the methylolated product obtained by reacting a triazine ring-containing amino compound such as melamine or benzoguanamine with formaldehyde. it can.

  As the alcohol compound used here, a lower alcohol having about 1 to 4 carbon atoms can be used, and specifically, a methoxymethylol melamine resin, a butylated methylol melamine resin or the like can be used. The molecular structure may be completely alkoxylated, a methylol group may remain, or an imino group may remain.

  As the resin structure of the alkoxylated melamine resin used in the present invention, the methoxymethylolated melamine resin is preferable because the compatibility with the polyimide resin and the curability at the time of curing are good, and more preferably, the methoxylation rate is 80% or more. More preferred are methoxymethylolated melamine resins.

  The resin structure of the melamine resin may be a polynuclear body by self-condensation. The degree of polymerization at this time is preferably about 1 to 5 in terms of compatibility and stability, and more preferably about 1.2 to 3.

  The number average molecular weight of the alkoxylated melamine resin used in the present invention may be 100 to 10,000. Preferably, 300 to 2000 is preferable in terms of compatibility with the polyimide resin and curability at the time of curing, and more preferably 400 to 1000.

  As the alkoxylated melamine resin used in the present invention, even if melamine, benzoguanamine, formalin and alcohol are simultaneously charged and reacted, melamine or benzoguanamine and formalin are reacted in advance to obtain a methylolated melamine compound and then alkoxy with the alcohol compound. You may do.

  Specific examples of commercially available alkoxylated melamine resins used in the present invention include, for example, commercial Cymel 300, 301, 303, 305 and the like manufactured by Nippon Cytec Industries. Examples of the methylol group-containing methoxymethylolated melamine resin include product Cymel 370 and 771 manufactured by Nippon Cytec Industries. Examples of the imino group-containing methoxylated melamine resin include commercial Cymel 325, 327, 701, 703, and 712 manufactured by Mitsui Cytec Co., Ltd. Examples of the methoxylated butoxylated melamine resin include product Cymel 232, 235, 236, 238, 266, 267, 285 manufactured by Nippon Cytec Industries. Examples of the butoxylated melamine resin include product Uban 20SE60 manufactured by Nippon Cytec Industries.

  The amount of the alkoxylated melamine resin used in the present invention is a polyimide resin resin because the physical properties of the polyimide resin and the synergistic effect due to the curing of the alkoxylated melamine resin can be obtained, and both excellent mechanical properties and high Tg can be achieved. It is preferable to mix | blend 1-30 weight part with respect to 100 weight part in conversion of solid content, 1-20 weight part is more preferable, 1-10 weight part is still more preferable, 2-7 weight part is especially preferable.

  As said isocyanate compound (D3), an aromatic isocyanate compound, an aliphatic isocyanate compound, an alicyclic isocyanate compound, etc. can be used, for example. Preferably, a polyisocyanate compound having two or more isocyanate groups in one molecule is preferable. A blocked isocyanate compound can also be used.

  As the silicate (D4), for example, methyl silicate, ethyl silicate, propyl silicate, butyl silicate and the like can be used.

  Examples of the alkylalkoxysilane (D5) include alkyltrialkoxysilane and dialkyl dialkoxysilane.

  Examples of the alkyltrialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, Examples thereof include phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, and phenyltributoxysilane.

  Examples of the dialkyl dialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, and diphenyldimethoxy. Silane, diphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldibutoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylethyldipropoxysilane, methylethyldibutoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane , Methylphenyldipropoxysilane, methylphenyldibutoxysilane, trimethylmethoxysilane, trimethyl ether Kishishiran, triethyl silane, triethyl silane, triphenyl methoxy silane, triphenyl ethoxy silane, and the like.

  Moreover, the condensate of alkyl alkoxysilane can also be used, for example, the condensate of the above-mentioned alkyl trialkoxysilane, the condensate of dialkyl dialkoxysilane, etc. are mentioned.

  Further, the resins of the present invention include binder resins such as polyester, phenoxy resin, PPS resin, PPE resin, polyarylene resin, curing agents such as phenol resins, polybasic acid anhydrides, cyanate compounds or reactive compounds, melamine, dicyandiamide, and guanamine. And its derivatives, imidazoles, amines, phenols having one hydroxyl group, organic phosphines, phosphonium salts, quaternary ammonium salts, photocationic catalysts and other curing catalysts, curing accelerators, fillers, and other additives It is also possible to add a defoaming material, a leveling agent, a slip agent, a wetting improver, an anti-settling agent, a flame retardant, an antioxidant, an ultraviolet absorber and the like to form a polyimide resin composition.

  Moreover, various fillers, organic pigments, inorganic pigments, extender pigments, rust preventives, and the like can be further added to the polyimide resin of the present invention as necessary to obtain a resin composition. These may be used alone or in combination of two or more.

  Examples of the filler include barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica, and alumina. Is mentioned.

  As the filler, those having various particle sizes can be used, and can be added to such an extent that the physical properties of the present resin and its composition are not impaired. Such an appropriate amount is in the range of about 5 to 80% by weight in terms of solid content, and is preferably used after being uniformly dispersed. As a dispersion method, it is possible to carry out dispersion by a known roll, bead mill, high-speed dispersion or the like, and the surface of the particles may be modified in advance with a dispersion treatment agent.

  Examples of the organic pigment include azo pigments; copper phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, and quinacridone pigments.

  Examples of the inorganic pigment include chromates such as chrome lead, zinc chromate and molybdate orange; ferrocyanides such as bitumen, titanium oxide, zinc white, bengara, iron oxide; metal oxides such as chromium carbide green, Cadmium yellow, cadmium red; metal sulfides such as mercury sulfide; selenides; sulfates such as lead sulfate; silicates such as ultramarine; carbonates, cobalt biored; phosphates such as manganese purple; aluminum powder, zinc dust Metal powders such as brass powder, magnesium powder, iron powder, copper powder and nickel powder; carbon black and the like.

  In addition, any of other coloring, rust prevention, and extender pigments can be used. These may be used alone or in combination of two or more.

  Resin compositions such as the polyimide resin and thermosetting resin composition of the present invention are dried by heating at 100 to 300 ° C. after preparing the polyimide resin of the present invention or its resin composition to form a coating or molding. Alternatively, it can be cured.

  The substrate used in the method for forming the coating film can be used without any particular limitation. Examples of the substrate include plastic, metal, wood, glass, inorganic material, and composite materials thereof.

Hereinafter, the present invention showing examples will be described in more detail, but the present invention is not limited to the following examples.

Example 1
Synthetic process In a flask equipped with a stirrer, thermometer and condenser, 1496 parts PGMAC (propylene glycol monomethyl ether acetate / boiling point 146 ° C.), 888 parts (4 mol) IPDI (isophorone diisocyanate) and 960 parts (5 mol) trimellitic anhydride And heated up to 140 ° C. The reaction proceeded with foaming. Reaction was carried out at this temperature for 4 hours to obtain a polyimide resin solution (X1). The inside of the system became a light brown clear liquid, and as a result of measuring the characteristic absorption in the infrared spectrum, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, completely disappeared and became 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ⁻¹ . Absorption of imide groups was confirmed. The acid value was 85 KOHmg / g in terms of solid content, and the molecular weight was a number average molecular weight of 1600 in terms of polystyrene. Further, it was a light brown transparent liquid having a nonvolatile content of 35%.

-Granulation process Next, this resin solution (X1) is spray-dried ("Spray dryer CL-8i type" manufactured by Okawara Kako Co., Ltd.), operating conditions: liquid temperature 70 ° C, drying temperature 85 ° C, nitrogen atmosphere, resin solution The solvent was dried using a viscosity of 150 mPa · s and a feed rate of 3.6 kg / h. When the obtained resin powder was measured for the diameter in a fixed direction with an optical microscope ("DIGITAL MICROSCOPE VHX" manufactured by Keyence Corporation), it was fibrous, spherical, or elliptical with a size of 0.1 to 100 µ accounting for 90% or more. It was an irregular powder. The non-volatile content of the resin powder was 100%. The melting temperature (T1 / 2) of this resin powder (Y1) was 275 ° C.

-Remelting process Next, the obtained imide resin powder was put into a 25 ml glass bottle, 5 parts of MEK was added to 1 part of the resin powder (Y1), and then stirred at room temperature (25 ° C.) An imide resin solution (Z1) was prepared by dissolving and diluting with “Awatori Netaro AR-250”).
(Example 2)
In the re-dissolution step, a polyimide resin solution (Z2) was obtained in the same manner as in Example 1 except that ethyl acetate was used instead of MEK.
(Example 3)
In the re-dissolution step, a polyimide resin solution (Z3) was obtained in the same manner as in Example 1 except that acetone was used instead of MEK.

(Comparative Example 1)
The polyimide resin solution (X1) having a non-volatile content of 35% obtained in Example 1 was placed in a 25 ml glass bottle, 5 parts of MEK was added to 1 part of the resin solution (X1), and then dissolved and diluted as in Example 1. Thus, an imide resin solution (Z4) was produced.
(Comparative Example 2)
A polyimide resin solution (Z5) was obtained in the same manner as in Comparative Example 1 except that ethyl acetate was used instead of MEK.
(Comparative Example 3)
A polyimide resin solution (Z6) was obtained in the same manner as in Comparative Example 1 except that acetone was used instead of MEK.

(Measurement Example 1 Evaluation of Dilution Stability)
The appearance of the polyimide resin solution (Z1 to Z6) after dissolution and dilution, the presence or absence of precipitates such as resin, the color of the solution, and the fluidity of the solution were observed, and the dilution stability was evaluated according to the following evaluation criteria. The results are shown in Table 1.

(Evaluation criteria for dilution stability)
○: The resin solution was transparent, had no precipitate, and was fluid.
Δ: Although fluid, the resin solution had deposits and turbidity occurred.
X: There was no fluidity, the resin solution had deposits and turbidity occurred.

(Example 4) Preparation of thermosetting resin solution 100 parts of polyimide resin solution (Z1) having a nonvolatile content of 35% obtained in Example 1, cresol novolac epoxy resin (epoxy equivalent 215, softening point 80 ° C) 7.2 Part (70/30 in solid content weight ratio) and 0.24 part of triphenylphosphine (curing catalyst) were mixed to prepare a thermosetting resin solution (W1). Various physical properties of the obtained thermosetting resin solution (W1) were evaluated by the following methods.

(Comparative Example 4)
100 parts of a polyimide resin solution (Z4) having a non-volatile content of 5.8% obtained in Comparative Example 1, 2.5 parts of cresol novolac epoxy resin (epoxy equivalent 215, softening point 80 ° C.) (70/30 in weight ratio of solids) ) And 0.08 part of triphenylphosphine (curing catalyst) were mixed to prepare a thermosetting resin solution (W2).

(Measurement Example 2 Evaluation of Dilution Stability)
Each of the thermosetting resin solutions (W1, W2) was put in a 25 ml glass bottle, 4 parts of the solvent described in Table 2 was added to 1 part of the resin solution (W1, W2), and then the same as in Example 1. A thermosetting resin solution was prepared by dissolution and dilution, and the dilution stability at that time was evaluated by the same method as in Measurement Example 1. The results are shown in Table 2.

(Measurement Example 3 Paintability Evaluation)
The thermosetting resin solutions (W1, W2) were each coated on a tin plate at room temperature with a 0.152 mil applicator. The appearance of the coating was evaluated according to the following evaluation criteria. The results are shown in Table 3.

(Evaluation criteria for paintability)
○: Transparent, glossy and flat surface.
Δ: Opaque but flat surface.
X: Opaque and not a flat surface.

(Measurement Example 5: Film-forming property of cured product)
The test pieces obtained by applying the thermosetting resin solutions (W1, W2) to the tin plate with an applicator so that the film thickness after drying was 30 μm were dried at 110 ° C. for 30 minutes. The coating film appearance was evaluated according to the following evaluation criteria. The results are shown in Table 4.

(Evaluation criteria for film-forming properties)
○: No abnormalities such as cracks are observed in the coating film.
Δ: Some cracks are observed in the coating film.
X: Cracks occurred on the entire surface of the coating film.

(Measurement example 6: Solder heat resistance of cured product)
A thermosetting resin solution (W1, W2) was applied to an 18 micron copper bed so that the film thickness after curing was 30 μm, and pre-dried at 150 ° C. for 5 minutes to prepare a B stage sample. . Next, the same 18-micron copper foil was placed on the resin surface, laminated at a maximum temperature of 175 ° C. under a pressure of 2 MPa for 60 minutes with a vacuum press machine, and then cooled to room temperature to form a cured coating film.

  The copper-coated cured coating film was immersed in a molten solder bath at 260 ° C. for 30 seconds and cooled to room temperature. This solder bath immersion operation was performed three times in total, and the appearance of the cured coating film was evaluated according to the following evaluation criteria. The results are shown in Table 4.

(Evaluation criteria for solder heat resistance)
○: Appearance abnormality is not observed in the coating film.
Δ: Abnormalities such as swelling and peeling are slightly observed in the coating film.
X: Abnormalities such as swelling and peeling are observed on the entire surface of the coating film.

(Measurement Example 7: Measurement of Tg and linear expansion coefficient of cured product)
A thermosetting resin solution (W1, W2) was applied onto a tin substrate so that the cured film thickness was 30 μm, dried for 20 minutes with a 70 ° C. dryer, and then cured at 200 ° C. for 1 hour. After cooling, the peeled cured coating film was cut into a width of 5 mm and a length of 30 mm to obtain a measurement sample.

  Subsequently, using a “thermal analysis system TMA-SS6000” manufactured by Seiko Electronics Co., Ltd., measurement was performed by the TMA (Thermal Mechanical Analysis) method under the conditions of a sample length of 10 mm, a heating rate of 10 ° C./min, and a load of 30 mN. In addition, Tg calculated | required the inflection point from the temperature-dimensional change curve in TMA measurement, and made the temperature Tg. Furthermore, the temperature range used for the linear expansion coefficient was determined from the displacement of the sample length at 50 to 60 ° C and 110 to 120 ° C. It shows that it is excellent in heat resistance, so that Tg is high, and it is excellent in dimensional stability, so that a linear expansion coefficient is small. The results are shown in Table 4.

DESCRIPTION OF SYMBOLS 1 ... Dryer body 2 ... Disc type atomizer 3 ... Raw material pump 4 ... Cyclone 5 ... Back filter 6 ... Circulation fan 7 ... Organic solvent recovery device 8 ... Refrigerator 9 ... Nitrogen gas heater 10 ... Oxygen meter A ... Polyimide powder B ... Nitrogen gas C ... Stock solution D ... Exhaust E ... Nitrogen gas

Claims (15)

Reaction of aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule with tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) A carboxy group-containing polyimide resin solution containing a carboxy group-containing polyimide resin and an organic solvent (B) obtained by
(1) In an organic solvent (A) or in the absence of a solvent, an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, and a tricarboxylic acid anhydride (b1) And / or a synthesis step of reacting with tetracarboxylic anhydride (b2) to obtain a carboxy group-containing polyimide resin,
(2) A granulating step of volatilizing the organic solvent (A) while spraying a resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin to obtain a powder of the carboxy group-containing polyimide resin;
(3) having a solvent dissolving step of dissolving the carboxy group-containing polyimide resin powder in the organic solvent (B), and
The organic solvent (A) is an organic solvent having a boiling point higher than the reaction temperature in the synthesis step, and the organic solvent (B) is an organic solvent having a boiling point lower than the reaction temperature in the synthesis step. A method for producing a carboxy group-containing polyimide resin solution. The method for producing a carboxy group-containing polyimide resin solution according to claim 1, wherein the organic solvent (B) is an organic solvent having a boiling point of 130 ° C or lower. The organic solvent (B) is one or more organic solvents selected from the group consisting of ketone organic solvents, ester organic solvents, ether organic solvents, alcohol organic solvents, aliphatic organic solvents, and aromatic organic solvents. A method for producing a carboxy group-containing polyimide resin solution according to claim 1. Organic solvent (B) is acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, tetrahydrofuran, N methylpyrrolidone, dimethylformamide, dimethylacetamide, cyclohexanone, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate and γ-butyrolactone The method for producing a carboxy group-containing polyimide resin solution according to claim 1, which is one or more organic solvents selected from the group consisting of: The content of the carboxy group-containing polyimide resin in the carboxy group-containing polyimide resin solution is 0.1 to 90% (weight basis). Production of the carboxy group-containing polyimide resin solution according to any one of claims 1 to 4. Method. Reaction of aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule with tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) A carboxy group-containing polyimide resin solution containing a carboxy group-containing polyimide resin and an organic solvent, wherein the ratio of the organic solvent having a boiling point of 130 ° C. or lower in the total organic solvent is 99% by weight or more, and The organic solvent having a boiling point of 130 ° C. or lower is at least one selected from the group consisting of ketones, esters, ethers, alcohols, aliphatic organic solvents, aromatic organic solvents, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; The ether is tetrahydrofuran or dioxane. Bokishi group-containing polyimide resin solution. The carboxy group-containing polyimide resin solution according to claim 6, wherein the content of the carboxy group-containing polyimide resin with respect to the polyimide resin solution is 0.1 to 90% (by weight). Reacting an aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule with a tricarboxylic acid anhydride (b1) and / or a tetracarboxylic acid anhydride (b2); Carboxy group-containing polyimide resin powder obtained in this way. The carboxy group-containing polyimide resin powder according to claim 8, comprising 90% or more of any one of fibrous, spherical, elliptical, and amorphous particles having a particle size of 0.01 to 2000 (μm). A method for producing a carboxy group-containing polyimide resin powder according to claim 8,
(1) In an organic solvent (A), an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, a tricarboxylic acid anhydride (b1) and / or tetra A synthesis step of reacting the carboxylic acid anhydride (b2) to obtain a carboxy group-containing polyimide resin;
(2) a granulating step of obtaining a carboxy group-containing polyimide resin powder by volatilizing the solvent while spraying a resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin, and an organic solvent (A) is the organic solvent whose boiling point is higher than the reaction temperature of the said synthetic | combination process, The manufacturing method of the carboxyl group containing polyimide resin powder characterized by the above-mentioned. A method for producing a carboxy group-containing polyimide resin solution, comprising a solvent dissolution step of dissolving the carboxy group-containing polyimide resin powder according to claim 8 in an organic solvent (B) having a boiling point of 130 ° C. or lower. A curable resin composition comprising the carboxy group-containing polyimide resin solution according to claim 6 and a curable resin component. A cured product obtained by curing the curable resin composition according to claim 12. Reaction of aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule with tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) A carboxy group-containing polyimide resin solution containing a carboxy group-containing polyimide resin and an organic solvent (B) obtained by
(1) In an organic solvent (A) or in the absence of a solvent, an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, and a tricarboxylic acid anhydride (b1) And / or a synthesis step of reacting with tetracarboxylic anhydride (b2) to obtain a carboxy group-containing polyimide resin,
(2) A granulating step of volatilizing the organic solvent (A) while spraying a resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin to obtain a powder of the carboxy group-containing polyimide resin;
(3) a solvent dissolution step of dissolving the carboxy group-containing polyimide resin powder in an organic solvent (B);
(4) having a step of mixing the obtained carboxy group-containing polyimide resin solution and a curable resin component, and
The organic solvent (A) is an organic solvent having a boiling point higher than the reaction temperature in the synthesis step, and the organic solvent (B) is an organic solvent having a boiling point lower than the reaction temperature in the synthesis step. A method for producing a curable resin composition. Reaction of aliphatic isocyanate compound and / or alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule with tricarboxylic acid anhydride (b1) and / or tetracarboxylic acid anhydride (b2) A carboxy group-containing polyimide resin solution containing a carboxy group-containing polyimide resin and an organic solvent (B) obtained by
(1) In an organic solvent (A) or in the absence of a solvent, an aliphatic isocyanate compound and / or an alicyclic isocyanate compound (a) having two or more isocyanate groups in the molecule, and a tricarboxylic acid anhydride (b1) And / or a synthesis step of reacting with tetracarboxylic anhydride (b2) to obtain a carboxy group-containing polyimide resin,
(2) A granulating step of volatilizing the organic solvent (A) while spraying a resin solution of the organic solvent (A) containing the carboxy group-containing polyimide resin to obtain a powder of the carboxy group-containing polyimide resin;
(3) a solvent dissolution step of dissolving the carboxy group-containing polyimide resin powder in an organic solvent (B);
(4) a step of mixing the obtained carboxy group-containing polyimide resin solution and a curable resin component;
(5) having a step of curing the obtained curable resin composition, and
The organic solvent (A) is an organic solvent having a boiling point higher than the reaction temperature in the synthesis step, and the organic solvent (B) is an organic solvent having a boiling point lower than the reaction temperature in the synthesis step. A method for producing a cured product.

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