JP2006316135A - Polyimide resin composition, resin coating and insulated wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting type aromatic polyimide resin composition, a resin coating and an insulated wire excellent in mechanical properties and hydrolysis. <P>SOLUTION: The polyimide resin composition is soluble in a polar solvent, etc. The polyimide resin is composed of an acid anhydride component mainly containing an aromatic tetracarboxylic dianhydride and an isocyanate component mainly containing an aromatic diisocyanate and the resin composition is obtained by decarboxylation and imidation reaction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyimide resin, and relates to an aromatic polyimide resin composition, a resin paint, and an insulated wire obtained by solubilizing a polyimide resin in a solvent.

  Polyimide resin is one of the highest heat resistance among polymer materials and is used in a wide range of fields because of its excellent physical properties. However, since it is generally inferior in processability, it can be dissolved in a solvent. Most of them are used at the stage of polyamic acid obtained from the synthesis of aromatic diamine having aromaticity and aromatic tetracarboxylic dianhydride. After casting this polyamic acid solution, polyimide is obtained by dehydrating ring-closing imidization.

  Polyamic acid polyimides include pyromellitic dianhydride (PMDA) consisting of one benzene ring as an acid component and 3,3'4,4'-benzophenonetetracarboxylic dianhydride in which two benzene rings are connected by a linking group. (BTDA), 4,4'-oxydiphthalic dianhydride (ODPA), biphenyl type 3,3'4,4'-biphenyltetracarboxylic dianhydride (S-BPDA), etc. Carboxylic dianhydrides or their isomers are used, and the connecting portion varies depending on the required performance. In some cases, butanetetracarboxylic dianhydride and 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-tolerate as long as they are acceptable in terms of physical properties such as heat resistance. Alicyclic tetracarboxylic dianhydrides such as dicarboxylic acid anhydrides may be used. The amine component includes paraphenylenediamine (PPD) consisting of one benzene ring, 2,4'-tolylenediamine (TDA), and 4,4'-diaminodiphenylmethane (DAM) in which two benzene rings are connected by a linking group. ), 4,4′-diaminodiphenyl ether (ODA), 4,4′-diaminodiphenyl sulfone (DAS), biphenylene-linked vitrylenediamine (TODA), or isomers thereof. Again, the linking group varies widely depending on performance. Similarly, alicyclic diamines may be used. Further, in these acid anhydrides and diamines, the hydrogen of each benzene ring may be substituted with an alkyl group, a phenyl group, and optionally a fluorine.

  As the solvent for polyamic acid, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), dimethylimidazolidinone (DMI), etc. are used, and aromatic In some cases, it may be diluted with a group alkylbenzene.

  If the diisocyanate has the above-mentioned diamines, the amino group can be changed to an isocyanate group by phosgenation. Currently, isocyanates used as urethane raw materials, especially 4,4'-diphenylmethane diisocyanate (MDI) obtained on the basis of DAM and 2,4'-tolylene diisocyanate (TDI) obtained on the basis of TDA, are more suitable for DAM and TDA. Is available at a lower cost.

  As described above, the reaction between the aromatic diamine and the aromatic tetracarboxylic dianhydride is a polyimide precursor, and a solution of polyamic acid soluble in the solvent is obtained. When an aromatic diisocyanate is reacted, since it is directly imidized by a decarboxylation reaction, the solubility in a solvent is generally extremely inferior. However, the solution obtained by the reaction of diamines and acid anhydrides, such as PPD and PMDA, which have a strong tendency to crystallinity and orientation, is a polyamic acid, but the solubility is remarkably deteriorated and is precipitated in the synthesis reaction stage. It cannot be obtained as a solution.

  Although a solvent-soluble polyimide resin that has been imidized is also commercially available, it does not have the heat resistance and solvent resistance as polyamic acid polyimide.

Japanese Patent Laid-Open No. 5-78484 JP 2003-119285 A

  Polyamic acid polyimide requires a dehydration ring-closing reaction to obtain a polyimide resin, which requires high-temperature heat treatment. Therefore, it has become a foothold in workability when some form is added such as obtaining a polyimide film by casting or baking coating a polyamic acid solution or obtaining a polyimide insulated wire.

  Polyamic acid polyimides have good performance, but most have poor hydrolyzability. It is speculated that this may be due to the reversibility of the dehydration imidization reaction during synthesis or unreacted carboxylic acid remaining slightly in the resin.

  Although the imide bond has a rigid molecular structure, the polyamic acid polyimide sometimes has mechanical properties such as wear resistance that are not as high as expected. Although it is possible to make a linear resin structure ideally as the cause of this, it is speculated that it actually binds to a monomer existing in the vicinity and has a cross-linked structure.

  The polyamic acid solution undergoes a slight polymerization at room temperature and thickens, so that the storage stability of the solution is inferior and generally requires low-temperature storage.

  Since the imide-complete solvent-soluble polyimide does not involve a thermosetting reaction, it is thermoplastic, has a low softening temperature, and has poor solvent resistance.

  In order to solve the above-mentioned problems, the object of the present invention is to use a diisocyanate instead of diamine as a raw material for the polyimide resin, change the imidization of the polyimide from a dehydration reaction to a decarboxylation reaction, and also use the diisocyanate or acid as the raw material. Thermosetting aromatic polyimide resin composition with excellent mechanical properties and hydrolyzability by obtaining a stable polyimide resin coating by compensating for a decrease in resin solubility by introducing a sulfone group into dianhydride Products, resin coatings and insulated wires.

  In order to achieve the above object, the invention of claim 1 is a polyimide resin composition soluble in a polar solvent or the like, wherein an acid anhydride component mainly composed of an aromatic tetracarboxylic dianhydride and an aromatic diisocyanate. An aromatic polyimide resin composition comprising an isocyanate component as a main component and obtained by decarbonation imidization reaction.

  In the invention of claim 2, as an acid anhydride component, 20 to 100 mol% of diphenylsulfone tetracarboxylic dianhydride and 0 to 80 mol% of several tetracarboxylic dianhydrides are copolymerized. It is a polyimide resin composition as described in above.

  Invention of Claim 3 is a polyimide resin composition of Claim 1 or 2 which copolymerized 20-100 mol% of diphenyl sulfone diisocyanate and several types of isocyanates 0-80 mol% as an isocyanate component.

  The invention of claim 4 is a polyimide resin paint characterized by solubilizing the polyimide resin composition according to any one of claims 1 to 3 in a solvent.

  The invention of claim 5 is an insulated wire characterized in that a film is formed on a conductor by the polyimide resin paint of claim 4.

  According to the polyimide resin coating material of the present invention, since it is imidized by decarboxylation reaction of an isocyanate component and an acid dianhydride component, very good mechanical properties and hydrolysis resistance are exhibited. The solvent solubility is soluble in a solvent such as NMP and has excellent room temperature stability due to the inclusion of the sulfone group and the copolymerization effect. Therefore, taking advantage of these characteristics, it can be used for applications that require hydrolysis resistance and scratch resistance other than those used in conventional polyamic acid polyimides such as in the super heat resistant field, and it can also be used for top coats. Can do.

  Embodiments of a polyimide resin composition, a resin paint, and an insulated wire in the present invention will be described below.

  First, the insulated wire 10 using the polyimide resin paint according to the present invention forms an insulating film 12 around the conductor 11 by applying and baking the polyimide resin paint on the conductor 11 as shown in FIG. Obtained.

  This polyimide resin paint is formed by solubilizing a polyimide resin composition in a solvent.

  The polyimide resin composition of the present invention is obtained by subjecting an acid anhydride component mainly composed of an aromatic tetracarboxylic dianhydride and an isocyanate component mainly composed of an aromatic diisocyanate to a decarbonation imidization reaction.

  After the polyimide resin composition low molecular weight aromatic polyimide resin coating is applied, etc., it becomes possible to obtain a high molecular weight aromatic polyimide resin by heat curing.

  Since diisocyanate and acid dianhydride are directly imidized by decarboxylation, the solubility in a solvent is remarkably reduced at the stage of coating. However, a sulfone group is used as a linking group connecting two raw materials, particularly two benzene rings, and By using several types of aromatic tetracarboxylic dianhydrides and aromatic diisocyanates, the solubility in solvents is improved without degrading various properties such as heat resistance by breaking crystallinity, orientation, and order. Thus, an aromatic polyimide resin paint can be obtained.

  Specifically, 3,3'4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) is suitable as the acid dianhydride, and its isomer can also be used. The blending amount is preferably in the range of 20 to 100 mol%, and more preferably in the range of 50 to 100 mol%. It can also be used alone. Although depending on the combination with diisocyanate and acid dianhydride used in combination, DSDA can be reduced when a raw material having relatively good solubility is used.

  The acid dianhydride used in combination with DSDA is not particularly limited. From the viewpoint of heat resistance, aromatic tetrahydrides such as BTDA (N, N-dimethylacetamide) and ODPA (4,4′-oxydiphthalic dianhydride) are used. Carboxylic dianhydrides are preferred. PMDA (pyromellitic dianhydride), S-BPDA (3,3'4,4'-biphenyltetracarboxylic dianhydride), etc. can also be used, but the combined amount can be suppressed to a small extent due to poor solubility. End up. Further, butanetetracarboxylic dianhydride and 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid are acceptable within the range acceptable in terms of physical properties such as heat resistance. An alicyclic tetracarboxylic dianhydride such as an anhydride may be used in combination.

  As the diisocyanate, 4,4'-diphenylsulfone diisocyanate (SDI) is preferable, and isomers thereof can also be used. About the compounding quantity, the range of 20-100 mol% is good, and the range of 50-95 mol% is still better. It can also be used alone. Although depending on the combination with an acid dianhydride or a diisocyanate used in combination, the amount of SDI can be reduced when a raw material having relatively good solubility is used. The diisocyanate used in combination with SDI is not particularly limited, but aromatic diisocyanate is desirable. From the viewpoint of versatility and heat resistance, MDI (including 4,4′-diphenylmethane diisocyanate and its isomer), TDI (including 2,4′-tolylene diisocyanate and its isomer), diphenyl ether diisocyanate, etc. desirable. Vitrylene diisocyanate (TODI), paraphenylene diisocyanate (PPDI), and the like can be used, but the combined amount is suppressed to a small extent because of poor solubility. Also suitable are xylylene diisocyanate (XDI), polymer MDI and multimers. In addition, aliphatic and alicyclic diisocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (H-MDI) can be used in combination as long as they are acceptable in terms of physical properties such as heat resistance.

  The solvent is not particularly limited as long as it does not inhibit the imidization reaction, but is highly soluble NMP (N-methyl-2-pyrrolidone), DMAC (N, N-dimethylacetamide), DMF (N, N-dimethylformamide), DMI (dimethylimidazolidinone) and the like are desirable. Aromatic alkylbenzenes and the like may be used in combination with γ-butyrolactone, valerolactone, or the like, or for dilution purposes.

  The polyimide resin paint stops the synthesis reaction by blocking the isocyanate component remaining in the synthesis solution with an appropriate molecular weight and stabilizes it as a paint. The molecular weight is not particularly limited, but 20000 or more tends to obtain excellent characteristics at the final heat curing. The isocyanate blocking agent also includes phenols, alcohols, oximes, etc., and is not particularly limited, but it is desirable that it contributes to the stabilization of the paint, and the block dissociates at the time of heat curing to increase the molecular weight. Selection is required depending on the application, heat curing conditions, paint storage conditions, and the like.

  In each Example, it carried out as follows.

  Raw materials shown in Examples 1 to 3 and Comparative Examples 1 to 5 below were charged into a flask equipped with a stirrer, a reflux condenser, a nitrogen inflow pipe, and a thermometer, respectively, and the polyimide resin paint was stirred in a nitrogen atmosphere. After stirring at 50 ° C. for 30 minutes to completely dissolve the raw materials, the mixture is heated to 100 ° C. in about 20 minutes and reacted at this temperature for 1 hour so that a polyimide resin solution having an average molecular weight of about 35000 is obtained. The solvent was diluted so that the non-volatile content was 20%.

  In Comparative Examples 2 and 3, after dissolving diamine completely, acid dianhydride was added little by little and reacted at room temperature for 6 hours to prepare a polyamic acid solution having a nonvolatile content of 20%.

  After casting the polyimide coating, a film having a thickness of 30 μm was obtained by heating at 300 ° C. for 5 minutes, and applied and baked on a copper conductor having a thickness of 0.8 mm to obtain an enameled wire having a thickness of 30 μm.

FIG. 1 is a view showing an electric wire coated with a polyimide paint according to the present invention.
An insulating coating 2 is obtained around the conductor 1 by applying and baking a polyimide coating on the conductor 1.

  Table 1 shows the properties of the examples and comparative examples, the properties of the obtained films and enameled wires.

  The test was conducted according to JIS. For hydrolyzability, a twisted enameled wire and 0.4 Vol% water were put into a glass tube with an internal volume of 300 ml, sealed, and then the rate of decrease in dielectric breakdown voltage after heat treatment at 120 ° C. for 1000 h was measured. The glass transition temperature Tg was measured by DSC.

Example 1
255.0 g (1.02 mol) of MDI (4,4′-diphenylmethane diisocyanate) as the isocyanate component and 214.8 g (0.6 mol) of DSDA (3,3′4,4′-diphenylsulfone) as the acid component Tetracarboxylic dianhydride), 128.8 g (0.4 mol) of BTDA (3,3′4,4′-benzophenone tetracarboxylic dianhydride) and NMP (N-methyl-2-pyrrolidone) as solvent 1600 g was added and synthesized, and then diluted with DMF (N, N-dimethylformamide) to obtain a polyimide resin paint having a resin concentration of 20% by weight.

(Example 2)
205.0 g (0.82 mol) liquid monomeric MDI (2,4 ′, 4,4 ′ isomer mixture) and 34.8 g (0.2 mol) TDI (2,4′-tolylene) as isocyanate components Isocyanate), 71.6 g (0.2 mol) of DSDA (3,3′4,4′-diphenylsulfone tetracarboxylic dianhydride) and 257.6 g (0.8 mol) of BTDA (3 mol) as the acid component. , 3′4,4′-benzophenonetetracarboxylic dianhydride) and 1600 g of NMP as a solvent were added and synthesized, and then diluted with DMF to obtain a polyimide resin paint having a resin concentration of 20% by weight.

(Example 3)
55.0 g (0.22 mol) of MDI and 240.0 g (0.8 mol) of SDI (4,4′-diphenylsulfone diisocyanate) as the isocyanate component and 62.0 g (0.2 mol) of the acid component ODPA (4,4′-oxydiphthalic dianhydride), 257.6 g (0.8 mol) of BTDA and 1600 g of DMAC (N, N-dimethylacetamide) as a solvent were added, and after synthesis, DMAC ( N, N-dimethylacetamide) to obtain a polyimide resin coating having a resin concentration of 20% by weight.

(Comparative Example 1)
255.0 g (1.02 mol) of MDI as the isocyanate component, 322.0 g (1.0 mol) of BTDA as the acid component, and 1600 g of NMP as the solvent were synthesized, diluted with DMAC, and the resin content concentration A 20% by weight polyimide resin paint was obtained.

(Comparative Example 2)
After 200.0 g (1.0 mol) of ODA as an amine component and 2000 g of NMP as a solvent were completely dissolved, 322.0 g (1.0 mol) of BTDA as an acid component was added while stirring little by little. Synthesis was performed for 6 hours to obtain a polyamic acid solution having a polyimide resin concentration of 20% by weight.

(Comparative Example 3)
After 198.0 g (1.0 mol) of DAM as an amine component and 2000 g of NMP as a solvent were completely dissolved, 322.0 g (1.0 mol) of BTDA as an acid component was added while stirring little by little. Synthesis was performed for 6 hours to obtain a polyamic acid solution having a polyimide resin concentration of 20% by weight.

(Comparative Example 4)
A solvent-soluble polyimide resin was added to 1600 g of NMP and completely dissolved to obtain a polyimide resin coating having a polyimide resin concentration of 20% by weight.

(Comparative Example 5)
255.0 g (1.02 mol) of MDI as an isocyanate component, 192.0 g (1.0 mol) of TMA as an acid component, and 1600 g of NMP as a solvent were added, and after synthesis, diluted with DMF, A polyamideimide resin paint having a resin concentration of 20% by weight was obtained.

  As shown in Table 1, the polyimide resin paints obtained in Examples 1 to 3 exhibit good room temperature stability. Comparative Example 1 was poor in solubility and could not be obtained as a polyimide resin paint. Since Comparative Examples 2 and 3 are polyamic acid solutions, an increase in molecular weight is observed at room temperature, and the room temperature stability is poor. The polyimide enamel wires obtained in Examples 1 to 3 have characteristics excellent in wear resistance and hydrolysis resistance as compared with the polyimide enamel wires obtained from the conventional polyamic acid shown in Comparative Examples 2 and 3. Compared with the polyamide-imide enamel wire of Comparative Example 5 which has the most excellent wear resistance and hydrolysis resistance among conventional enamel wires, the wear resistance is good and the hydrolysis resistance is almost the same. Tg of Examples 1 to 3 and Comparative Examples 1 to 4 are all around 300 ° C., but Comparative Example 4 exhibits thermoplasticity, and therefore has a low softening resistance as an enameled wire.

It is sectional drawing of the insulated wire obtained by this invention.

Explanation of symbols

10 Insulated wire 11 Conductor 12 Film

Claims (5)

  In a polyimide resin composition soluble in a polar solvent or the like, it comprises an acid anhydride component mainly composed of aromatic tetracarboxylic dianhydride and an isocyanate component mainly composed of aromatic diisocyanate, and is subjected to decarbonation imidization reaction. An aromatic polyimide resin composition obtained.   The polyimide resin composition according to claim 1, wherein 20 to 100 mol% of diphenylsulfone tetracarboxylic dianhydride and 0 to 80 mol% of several kinds of tetracarboxylic dianhydrides are copolymerized as an acid anhydride component. .   The polyimide resin composition according to claim 1 or 2, wherein 20 to 100 mol% of diphenylsulfone diisocyanate and 0 to 80 mol% of several kinds of isocyanates are copolymerized as an isocyanate component.   A polyimide resin paint, wherein the polyimide resin composition according to claim 1 is solubilized in a solvent. An insulated wire, wherein a film is formed on a conductor with the polyimide resin paint according to claim 4.

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