JP2014114429A - Solvent-soluble polyimide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent-soluble polyimide resin that is superior in low linear expansion coefficients, colorless transparency, and heat resistance.SOLUTION: Used is a polyimide resin obtained by an imidization polymerization reaction of bicyclo[4.2.0]octane-3,4,7,8-tetracarboxylic acid dianhydride and an alicyclic diamine compound, with the alicyclic diamine compound being in the range of 90-110 in terms of molar ratio in relation to 100 of the tetracarboxylic acid dianhydride.

Description

  The present invention relates to a solvent-soluble polyimide resin.

  Conventionally, polyimide resins have been widely used as resins for electronic materials because of their excellent heat resistance, strength, and electrical insulation. However, since general polyimide resins are highly colored, their use is limited.

  Therefore, research on improving the hue of polyimide resin has been conducted, and a technique using a fluorine compound as a polyimide resin raw material has been discovered (Non-Patent Document 1). However, the polyimide resin raw material having fluorine atoms is uneconomical because it is difficult to produce and expensive.

  As another method for improving the hue of a polyimide resin, studies have been conducted using an aliphatic or alicyclic compound as a polyimide resin raw material. In particular, it has been found that the use of alicyclic acid dianhydrides has a great effect on hue improvement (Non-patent Document 2). Moreover, when the location which has an aromatic ring or a multiple bond is contained in a polyimide resin, it is known that the deterioration of a hue will arise when it irradiates with an ultraviolet-ray (patent document 1). Therefore, an alicyclic polyimide resin is considered preferable as an optical material.

  In addition, it is generally known that polyimide molded products are prepared by thermal imidization reaction of polyamic acid, which is a precursor compound, but the necessary temperature at that time is as high as 300 ° C or higher. Applications that cannot be used in the process have come out. In particular, in the case of alicyclic polyamic acid, thermal decomposition tends to occur at a high temperature, and the polyimide resin tends to be colored. Therefore, development of a solvent-soluble alicyclic polyimide resin that does not require a thermal imidization reaction is desired.

  However, the alicyclic polyimide resin is difficult to increase in molecular weight because the raw material tetracarboxylic acid and diamine form a strong salt during the polymerization, and often becomes a brittle molded product. As a solvent-soluble alicyclic polyimide resin, an alicyclic polyimide resin of hydrogenated pyromellitic dianhydride and 4,4'-methylenebis (cyclohexylamine) is known (Patent Document 2). The polyimide resin is excellent in colorless transparency and heat resistance, but has a linear expansion coefficient as high as 60 ppm / K or more, and retains colorless transparency and heat resistance as a solvent-soluble alicyclic polyimide resin while maintaining linear transparency coefficient and heat resistance. A polyimide resin having a small size has been desired.

"Latest Trends in Revolutionary Polyimide IV-Diversified Types, Characteristics, Processability and Actual Status of Application Expansion-11th Anniversary Special Edition" Published in March 2008 Published by Sumibe Research Co., Ltd. 39 "Latest Polyimide-Basics and Applications-" Issued the first edition of the first edition on January 28, 2002 Editor Edited by Japan Polyimide Study Group Ikuo Imai, Rikio Yokota Issuer Takashi Yoshida Publisher NTS Corporation 241-242

JP 2000-196151 A JP 2008-045054 A

  An object of this invention is to provide the solvent-soluble polyimide resin excellent in the low linear expansion coefficient, colorless transparency, and heat resistance.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a specific tetracarboxylic dianhydride and a specific alicyclic diamine compound as raw materials, resulting in a low linear expansion coefficient, colorlessness. As a result of finding out that a solvent-soluble polyimide resin excellent in transparency and heat resistance can be obtained, and further earnestly examining it, the present invention has been completed.

  That is, the present invention provides the following polyimide resins.

[Claim 1]
General formula (1)
A tetracarboxylic dianhydride represented by:
A solvent-soluble polyimide resin obtained by imidation polymerization reaction of the alicyclic diamine compound with respect to the tetracarboxylic dianhydride 100 in a molar ratio in the range of the alicyclic diamine compound 90 to 110.

[Section 2]
Item 2. The polyimide resin according to Item 1, wherein the alicyclic diamine compound is at least one kind represented by the diamine compound of the following general formula (2).

[Section 3]
Item 5. A polyimide varnish containing the polyimide resin according to item 1 and an organic solvent.

[Claim 4]
Item 5. A polyimide molded body obtained by molding the polyimide varnish according to Item 3.

[Section 5]
Item 5. The polyimide molded body according to Item 4, wherein the polyimide molded body is in the form of a film, a film, or a sheet.

[Claim 6]
Item 6. The polyimide molded article according to item 4 or 5, wherein the polyimide molded article has a linear expansion coefficient of 60 ppm / K or less, a total light transmittance of 85% or more, and a glass transition temperature of 250 ° C or more.

[Claim 7]
Item 7. A plastic substrate comprising the polyimide molded body according to any one of Items 4 to 6.

[Section 8]
Item 8. An electrical component or electronic component comprising the plastic substrate according to Item 7.

[Claim 9]
Item 3. A heat-resistant insulating material, heat-resistant paint, heat-resistant coating material, or heat-resistant adhesive using the polyimide resin according to Item 1 or 2.

  According to the present invention, a solvent-soluble polyimide resin excellent in low linear expansion coefficient, colorless transparency and heat resistance can be obtained, and a plastic substrate formed of a molded body of the polyimide resin can be used for an electrical component and an electronic component. .

  In addition, the polyimide resin can be used for heat-resistant insulating materials, heat-resistant paints, heat-resistant coating materials, and heat-resistant adhesives.

[Solvent-soluble polyimide resin]
The solvent-soluble polyimide resin of the present invention has the general formula (1)
A tetracarboxylic dianhydride represented by:
It is obtained by performing an imidization polymerization reaction with an alicyclic diamine compound.

(Tetracarboxylic dianhydride)
The tetracarboxylic dianhydride is a bicyclo [4.2.0] octane-3,4,7,8-tetracarboxylic dianhydride represented by the above general formula (1), and is a solvent of the present invention. It is a constituent component of a soluble polyimide resin.

  As a method for producing the tetracarboxylic dianhydride represented by the general formula (1), a photodimerization reaction is recommended. As specific examples, equimolar amounts of tetrahydrophthalic anhydride and maleic anhydride are dissolved in a ketone solvent such as methyl ethyl ketone, an ester solvent such as ethyl acetate, or an ether solvent such as dioxane, and a high pressure mercury lamp or the like. The tetracarboxylic dianhydride reactant can be obtained by irradiating light of 250 to 400 nm using.

  Tetracarboxylic dianhydrides include tetracarboxylic acids or mono, di, tri or tetra acid chlorides of tetracarboxylic acids and mono, di, tri or tetra esters of lower alcohols having 1 to 4 carbon atoms. It can also be used as a derivative.

  The tetracarboxylic dianhydride can be used by replacing a part of the tetracarboxylic dianhydride with another tetracarboxylic dianhydride as long as the effects of the present invention are not impaired. Other tetracarboxylic dianhydrides include aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides.

  Specifically, examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, and 4,4′-oxydiphthalic acid dianhydride. Anhydride, 2,2 ′, 3,3′-benzophenonetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-di Carboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 1,1 -Bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane Dianhydride 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 4,4 ′-(p-phenylenedioxy) diphthalic dianhydride, 4,4 ′-(m-phenylenedioxy) diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2-ethylenebis (anhydrotrimellitate), 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro- 2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1.3-dione and derivatives thereof are exemplified.

  Examples of the alicyclic tetracarboxylic dianhydride include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl- 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6- Tricarboxynorbonane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1 , 2-dicarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and derivatives thereof.

  Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride, and derivatives thereof. Illustrated.

  Said other tetracarboxylic dianhydride can be used for the imidation polymerization reaction alone or in combination of two or more.

  When a part of the tetracarboxylic dianhydride is used in place of the other tetracarboxylic dianhydrides, the amount used is preferably 20 with respect to the total number of tetracarboxylic dianhydrides. A mol% or less, more preferably 10 mol% or less, particularly 5 mol% or less is recommended.

(Alicyclic diamine compound)
The alicyclic diamine compound is a constituent component of the polyimide resin of the present invention. The alicyclic diamine compound is not particularly limited, and commercially available products or those obtained by a conventionally known production method can be used.

Specific examples of the alicyclic diamine compound include diaminocyclohexane, diaminodicyclohexylmethane, dimethyl-diaminodicyclohexylmethane, tetramethyl-diaminodicyclohexylmethane, diaminodicyclohexylpropane, diaminobicyclo [2.2.1] heptane, bis (aminomethyl). ) -Bicyclo [2.2.1] heptane, 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1.0 ^2,6 ] decane, 1,3-bisaminomethylcyclohexane And isophoronediamine. Among these, diaminocyclohexane, diaminodicyclohexylmethane, dimethyl-diaminodicyclohexylmethane, diaminobicyclo [2.2.1] heptane, bis (aminomethyl) -bicyclo [2.2.1] heptane, 3 (4), 8 (9) -Bis (aminomethyl) tricyclo [5.2.1.0 ^2,6 ] decane, 1,3-bisaminomethylcyclohexane and isophoronediamine are preferred. As a particularly preferred diamine compound, a diamine compound represented by the following general formula (2) is exemplified. These alicyclic diamine compounds may be used alone or in combination of two or more.

 The alicyclic diamine compound can be used by replacing a part of the alicyclic diamine compound with another diamine compound as long as the effects of the present invention are not hindered. Examples of other diamine compounds include aromatic diamine compounds and aliphatic diamine compounds.

  Specifically, examples of the aromatic diamine compound include m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 3,4 '-Diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3 , 4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3 -Aminophenoxy) benzene, 1,3-bis (3 Aminophenoxy) benzene, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) ) Phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4 Examples include-(3-aminophenoxy) phenyl] ether, 9,9-bis (4-aminophenyl) fluorene, O-tolidine, m-tolidine and the like.

  Specific examples of the aliphatic diamine compound include ethylene diamine, hexamethylene diamine, octamethylene diamine, and decamethylene diamine.

  The other diamine compounds described above can be used alone or in combination of two or more kinds for the imidation polymerization reaction.

  When a part of the alicyclic diamine compound is replaced with the other diamine compound, the amount used is preferably 20 mol% or less, more preferably 10 mol, based on the number of moles of the total diamine compound. % Or less, especially 5 mol% or less is recommended.

  The molar ratio in the imidation polymerization reaction according to the present invention is in the range of all diamine compounds 90 to 110, more preferably in the range of 95 to 105, with respect to all tetracarboxylic dianhydrides 100. More preferably, it is the range of 98-102. By performing the imidization polymerization reaction within this range, a polyimide resin having a sufficient degree of polymerization can be obtained.

  In the present specification and claims, the alicyclic diamine compound is described in the form of “diamine”. However, as long as the effect of the present invention is exhibited for the purpose of improving the reactivity, an amino group is used instead. A compound obtained by converting a part or all of the group into an isocyanate group, a silylated compound, or the like can be used.

(Reaction solvent)
The reaction solvent used in the imidation polymerization reaction according to the present invention may be any reaction solvent as long as it can dissolve the polyimide resin produced from the imidization polymerization reaction. For example, preferred examples include aprotic solvents, phenol solvents, ether solvents, carbonate solvents, and the like.

  Specific examples of the aprotic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea and the like. Amide solvents, lactone solvents such as γ-butyrolactone, γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide, hexamethylphosphine triamide, sulfur-containing dimethylsulfone, dimethylsulfoxide, sulfolane, etc. Examples thereof include a system solvent, a ketone solvent such as acetone, cyclohexane and methylcyclohexanone, an amine solvent such as picoline and pyridine, and an ester solvent such as acetic acid (2-methoxy-1-methylethyl).

  Specific examples of the phenol solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4 -Xylenol, 3,5-xylenol and the like are exemplified.

  Specific examples of the ether solvent include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetrahydrofuran, 1,4-dioxane and the like.

  Specific examples of the carbonate solvent include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, and the like. You may use said reaction solvent individually or in mixture of 2 or more types.

  Among these reaction solvents, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, and γ-butyrolactone are particularly recommended.

  The amount of the reaction solvent used may be an amount that can dissolve the produced all-alicyclic polyimide resin. It is recommended that the specific concentration of the total alicyclic polyimide resin be adjusted to preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and still more preferably 10 to 30% by weight.

  The reaction solvent may be the same as or different from the organic solvent constituting the polyimide varnish according to the present invention, but is preferably the same in consideration of the complexity of the solvent replacement operation.

(Imidation polymerization reaction)
As a method of imidation polymerization reaction, (1) tetracarboxylic dianhydride and diamine compound are heated in the presence of a reaction solvent and a small amount of azeotropic solvent, and the generated water is distilled out of the system by azeotropic distillation. Thermal imidization method, (2) Chemical imidization method using dehydration action of carbodiimide compounds such as acid anhydrides such as acetic anhydride and propionic anhydride, or dicyclohexylcarbodiimide after producing polyamic acid as polyimide precursor, (3) Examples thereof include a thermal imidization method in which a polyamic acid as a polyimide precursor is produced and then heated to 300 ° C. or higher.

  Of the above polyimide resin production methods, the thermal imidation method (1) is industrially preferable. For example, the total amount of tetracarboxylic dianhydride and diamine compound is dissolved in the reaction solvent, or tetracarboxylic dianhydride is dissolved. And / or after partially dissolving the diamine compound, it is preferably heated to 100 to 250 ° C., more preferably 150 to 200 ° C., and water formed in the system is distilled off with an azeotropic solvent to perform imidization polymerization. The method of reacting is mentioned.

  Moreover, the polymer terminal of a polyimide resin can be made into an amine terminal by using a diamine compound excessively with respect to tetracarboxylic dianhydride, On the other hand, using tetracarboxylic dianhydride more excessively than a diamine compound. Thus, the polymer terminal of the polyimide resin can be made an acid terminal.

  Examples of the azeotropic solvent for distilling the generated water out of the system include aromatic hydrocarbons such as toluene, xylene and solvent naphtha, and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and dimethylcyclohexane. These can be used alone or as a mixed system. The amount used is usually about 1 to 30% by weight, preferably about 5 to 10% by weight, based on the amount of the reaction solvent.

  The inside of the reaction system is desirably an inert gas atmosphere from the viewpoint of preventing coloration and safety of the reaction system. Usually, a method of replacing the inside of the reaction system with an inert gas and allowing the inert gas to flow during the reaction is recommended. Examples of the inert gas include nitrogen and argon.

  In the imidation polymerization reaction according to the present invention, a known catalyst can be used. However, it is preferable to carry out the reaction in the absence of a catalyst from the viewpoints of complicated post-treatment, deterioration of the storage stability of the polyimide varnish due to the residual amount of catalyst used, and coloring of the polyimide varnish.

  When a catalyst is used, for example, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, trimethylamine, Organic base catalysts such as butylamine, imidazole, N, N-dimethylaniline, N, N-diethylaniline, inorganic bases represented by potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate Examples are catalysts.

  Examples of the acid catalyst include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and the like. Is exemplified.

  The reaction time of the imidation polymerization reaction is preferably about 2 to 10 hours after the start of distilling of the produced water, although it depends on the charging ratio and the substrate concentration. When reaction time is too short, the tendency for imidation ratio to become low is recognized. If the reaction time is too long, the reaction system may partially cause a thermal crosslinking reaction to thicken the reaction system or form a gel-like material, or the reaction system may be colored due to thermal degradation of the reaction solvent. .

  The number average molecular weight of the polyimide resin of the present invention obtained by imidation polymerization reaction is preferably 6,000 or more, and the weight average molecular weight is 10,000 or more, more preferably the number average molecular weight is 6,000 to 100. And a weight average molecular weight in the range of 10,000 to 500,000. This range is a range having a degree of polymerization that can give a molded product. In addition, in this specification and a claim, the molecular weight of a polyimide resin is the value measured by the method described in the Example of the postoperative.

  The imidation rate in the imidation polymerization reaction is usually 70% or more, preferably 80% or more, more preferably 90% or more, and particularly 95% or more. Furthermore, it may be desirable to make the imidization rate close to 100% depending on the use application of the polyimide resin.

  In addition, known monofunctional acid anhydrides, monoamines and the like used in this field can be used in combination as an end cap agent for the purpose of controlling the molecular weight and the like within a range not impairing the effects of the present invention. Specific examples of the end cap agent include phthalic anhydride, maleic anhydride, nadic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. for acid anhydrides, and aniline, methylaniline, allylamine, etc. for monoamines. .

[Polyimide varnish]
The polyimide varnish of the present invention is characterized by containing a polyimide resin and an organic solvent.

  As a method for preparing a polyimide varnish, (i) a method of using a reaction solvent solution of a polyimide resin obtained by an imidization polymerization reaction as it is as a polyimide varnish, (ii) a reaction solvent solution of a polyimide resin obtained by an imidization polymerization reaction Examples are a method of obtaining a polyimide varnish by isolating a polyimide resin from the following and then dissolving the isolated polyimide resin in a desired organic solvent.

  Although it can select suitably as a viscosity of a polyimide varnish by a desired use, Preferably it is 0.1-500 Pa.s, More preferably, it is 1-100 Pa.s.

  The concentration of the polyimide resin in the polyimide varnish is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and further preferably 10 to 30% by weight.

  The organic solvent is not particularly limited as long as it is an organic solvent capable of dissolving the polyimide resin according to the present invention, and specific examples include those exemplified as the reaction solvent. These can be used alone or as a mixed system. Among these, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, and γ-butyrolactone are recommended.

  Moreover, when obtaining the coating film of a polyimide resin from a polyimide varnish, a part of organic solvent can be replaced with a low boiling point solvent for the purpose of performing a drying process efficiently. Such low boiling point solvents include aromatic hydrocarbons such as toluene, xylene, solvent naphtha, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, dimethylcyclohexane, propylene glycol monomethyl ether, or acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. The ketones are exemplified. When these low-boiling solvents are used, the amount used is preferably 1 to 30% by weight, more preferably 5 to 20% by weight, based on the total amount of organic solvent.

  Moreover, you may add another component to the polyimide varnish of this invention in the range which does not inhibit the effect of this invention. For example, polyester resin, polyimide resin (excluding the polyimide resin of the present invention), polymer compound such as polyamideimide resin, polyamide resin, smoothing agent, leveling agent, defoaming agent, flame retardant, antifoaming agent, antioxidant Etc. are exemplified.

  The polyimide varnish thus obtained is excellent in storage stability and used for various purposes.

[Polyimide molded product]
The polyimide molded body of the present invention is obtained by molding the polyimide varnish. As a method for molding, a conventionally known method can be used without any particular limitation.
For example, after the polyimide varnish is applied to a substrate (after being applied or formed into a film, film, or sheet), the organic solvent is removed from the polyimide varnish to form a film, film, or sheet polyimide. The method etc. which shape | mold into a molded object are illustrated.

  As an example of producing a polyimide molded body, a polyimide varnish is cast on a PET substrate (polyethylene terephthalate substrate), and is placed in a vacuum dryer (decompression degree 1 to 10 mmHg) at room temperature for 30 minutes to 2 hours, and further about 200 ° C Until 30 minutes to 2 hours, and the solvent is distilled off at that temperature for 1 to 4 hours. After cooling to room temperature, the polyimide film formed on the PET substrate is taken out from the vacuum dryer and peeled off from the PET substrate. Fix the peeled polyimide film to a stainless steel metal frame, and again raise the temperature from room temperature to 230 to 280 ° C. in 1 to 4 hours in a vacuum dryer, and dry at that temperature for 2 to 5 hours to completely remove the solvent. After distilling off and cooling to room temperature, a polyimide film can be obtained by taking out from the vacuum dryer. A method of adjusting the thickness of the polyimide film thus obtained to a target thickness by adjusting the coating thickness at the time of casting can be mentioned.

  The range of the linear expansion coefficient of the polyimide resin of the present invention is preferably 60 ppm / K or less, more preferably 58 ppm / K or less, and particularly preferably 56 ppm / K or less. The linear expansion coefficient is a value obtained by the method described in Examples described later in the present specification and claims. For example, the range of the above linear expansion coefficient is an effective range particularly for the use of a transparent flexible substrate such as an organic EL.

  The colorless transparency of the polyimide resin of the present invention can be evaluated by the total light transmittance. The range of the total light transmittance is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance is a value obtained by the method described in Examples described later in this specification and claims. For example, the above-mentioned total light transmittance range is an effective range particularly in applications requiring colorless transparency.

  The heat resistance of the polyimide resin of the present invention can be evaluated by the glass transition temperature. The range of the glass transition temperature is preferably 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher. The glass transition temperature is a value obtained by the method described in Examples described later in the present specification and claims. For example, the above glass transition temperature range is an effective range particularly in applications requiring heat resistance.

[Plastic substrates / Electric and electronic components]
The plastic substrate of the present invention is characterized by comprising the polyimide molded body. As the manufacturing method, a conventionally known manufacturing method can be used.

  The plastic substrate is suitably used for, for example, a flexible transparent substrate because the polyimide molded body of the present invention has a low coefficient of linear expansion, a high total light transmittance, and a high glass transition temperature.

  Moreover, many flexible transparent substrates are used by an electrical component or an electronic component, for example, are used suitably as components, such as electronic paper, an organic solar cell, organic EL lighting, and a flexible liquid crystal display.

[Heat-resistant insulation / heat-resistant paint / heat-resistant coating / heat-resistant adhesive]
The heat-resistant insulating material, heat-resistant coating material, heat-resistant coating material or heat-resistant adhesive material of the present invention uses the polyimide resin of the present invention. As the manufacturing method, a conventionally known manufacturing method can be used. In any case, the polyimide resin is suitably used because it has a low linear expansion coefficient, a high total light transmittance, and a high glass transition temperature.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic in an Example and a comparative example and the abbreviation of a compound are as follows.

<Abbreviation of compound>
[Tetracarboxylic dianhydride (A)]
BCODA: Bicyclo [4.2.0] octane-3,4,7,8-tetracarboxylic dianhydride HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride BTA-H: Bicyclo [2 2.2] Octane-2,3,5,6-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride TDA: 4- (2,5-dioxotetrahydrofuran N-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride [diamine compound (B)]
HDAM: 4,4′-methylenebis (cyclohexylamine)
TCDDA: 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1.0 ^2,6 ] decane NBDA: norbornanediamine DMHDAM: 2,2′-dimethyl-4,4′-methylenebis (Cyclohexylamine)
[Reaction solvent]
NMP: N-methyl-2-pyrrolidone [silylating agent]
BSA: N, O-bis (trimethylsilyl) acetamide

<Number average molecular weight and weight average molecular weight of polyimide resin>
About 1 g of a polyimide resin reaction solution (polyimide varnish) is diluted with about 30 ml of N, N-dimethylformamide to prepare a sample solution for molecular weight measurement. The number average molecular weight (Mn) and weight average molecular weight (Mw) in terms of polystyrene were determined under the following measurement conditions using gel permeation chromatography (GPC).
[Measurement condition]
Device: EcoSEC HLC-8320GPC manufactured by Tosoh Corporation
Column: manufactured by Tosoh Corporation One SuperH-H and three SuperHM-Ms connected in series Column temperature: 40 ° C
Eluent: (5.15 mmol / L-lithium bromide + 5.10 mmol / L-phosphoric acid) / N, N-dimethylformamide Flow rate: 0.5 mL / min
Detector: RI

<Evaluation of solvent solubility>
Solvent solubility was evaluated by visually observing the state after adjusting the concentration of the polyimide resin to 15% by weight after completion of the imidation polymerization reaction and leaving it at room temperature for 24 hours. The criteria for the evaluation are as follows. On the basis of this criterion, ◯ is excellent in solvent solubility. It becomes evaluation that x is inferior to solvent solubility. The criteria for the evaluation are as follows.
○: Neither generation of precipitate nor gelation of the reaction solution was observed even after standing for 24 hours.
X: Generation of precipitates or gelation of the reaction solution was clearly observed within 24 hours.

<Linear expansion coefficient>
In accordance with JIS K7197 (1991), the polyimide film (40 μm) was heated in a normal air dryer at 300 ° C. for 30 minutes for stress relaxation treatment. 4.0 × 10.0 mm cut from this film was measured using a TMA / SS6100 manufactured by SII NanoTechnology Co., Ltd. under the conditions of a nitrogen flow rate of 200 ml / min and a heating rate of 10 ° C./min. The average value of the measured values was taken as the linear expansion coefficient.

<Total light transmittance>
Compliant with JIS K7361-1 (1997 years), polyimide film (40 [mu] m) using a Toyo Seiki Seisakusho HAZE-GUARD II _Ltd., was measured by single beam method using illuminant _{D 65.}

<Glass transition temperature>
Using a dynamic viscoelasticity measuring device RHEOGEL-E4000 (manufactured by UPM), tan δ of the polyimide molded body was measured under the following measurement conditions. The maximum value of tan δ was defined as the glass transition temperature (° C.).
Measurement condition;
Measurement mode: Tensile mode Sine wave: 10 Hz
Temperature increase rate: 5 ° C / min
Air flow rate: 10L / min

<Mechanical properties evaluation>
The “elastic modulus”, “strength”, and “elongation” of the polyimide molded body were measured according to JIS K-7161 (1994) by using a universal material testing machine 5565 manufactured by Instron.

[Production example]
BCODA was produced with reference to US Pat. No. 3,234,431. Specifically, 95.0 g (969 mmol) of maleic anhydride and 192.0 g of 1,2,3,6-tetrahydrophthalic anhydride were added to a 1500 ml internal irradiation type Pyrex (registered trademark) glass five-necked reaction flask. (1262 mmol) and 1,200 g of n-butyl acetate were charged and stirred and dissolved at room temperature while covering the outer wall of the reactor with aluminum foil. Further, nitrogen gas was bubbled for 15 minutes to remove oxygen in the reaction vessel. Subsequently, the reaction vessel was cooled to 20 ° C. while stirring, and light irradiation was continued for 24 hours using a 400 W high-pressure mercury lamp in a light source cooling tube in the center of the flask. After completion of the reaction, the precipitated crystals were filtered, washed with 60 g of n-butyl acetate, and then dried to obtain 59.9 g (239 mmol, 25% yield) of BCODA crystals.

[Example 1]
BCODA 13.37 g (53 mmol), HDAM 11.02 g (52 mmol) as a diamine compound, NMP 114.8 g as a reaction solvent in a 200 mL four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, separator decanter, and condenser tube Then, 12.8 g of xylene was charged as an azeotropic solvent, and the inside of the reaction system was purged with nitrogen. Then, the mixture was stirred at 180 ° C. in a nitrogen stream, and a dehydration imidation polymerization reaction was performed for 5 hours while removing the generated water from the system. . After the reaction, NMP was added so that the resin concentration was 15% by weight to obtain an NMP solution of the polyimide resin of the present invention (polyimide varnish of the present invention). Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Example 2]
A polyimide varnish of the present invention was obtained in the same manner as in Example 1 except that the diamine compound was changed to 10.30 g (53 mmol) of TCDDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Example 3]
A polyimide varnish of the present invention was obtained in the same manner as in Example 1 except that the diamine compound was changed to 5.57 g (26.5 mmol) of HDAM and 4.09 g (26.5 mmol) of NBDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Example 4]
A polyimide varnish of the present invention was obtained in the same manner as in Example 1 except that the diamine compound was changed to 5.57 g (26.5 mmol) of HDAM and 5.15 g (26.5 mmol) of TCDDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Example 5]
A polyimide varnish of the present invention was obtained in the same manner as in Example 1 except that the diamine compound was changed to HDAM 5.57 g (26.5 mmol) and DMHDAM 6.32 g (26.5 mmol). Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Comparative Example 1]
A polyimide varnish was obtained in the same manner as in Example 1 except that BCODA was changed to 11.88 g (53 mmol) of HPMDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Comparative Example 2]
A polyimide varnish was obtained in the same manner as in Example 3 except that BCODA was changed to 11.88 g (53 mmol) of HPMDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Comparative Example 3]
Except that BCODA was changed to 13.26 g (53 mmol) of BTA-H, an attempt was made to produce a polyimide varnish by the same method as in Example 1. However, when the reaction temperature reached 180 ° C., the resin became insoluble and precipitated. It was cloudy white.

[Comparative Example 4]
After adding 11.15 g (53 mmol) of HDAM, 10.78 g (53 mmol) of silylating agent BSA and 114.8 g of NMP to a 200 mL Erlenmeyer flask equipped with a stirrer and stirring for 15 minutes, 13.26 g (53 mmol) of BTA-H was added overnight. Stirring gave a polyamic acid varnish. The measurement results of the average molecular weight of the obtained polyamic acid varnish are shown in Table 1.

[Comparative Example 5]
Except that BCODA was changed to 10.39 g (53 mmol) of CBDA, an attempt was made to prepare a polyimide varnish by the same method as in Example 1, but when the reaction temperature reached 180 ° C., the resin became insoluble and precipitated and became cloudy white. It was.

[Comparative Example 6]
To a 200 mL Erlenmeyer flask equipped with a stirrer, 11.15 g (53 mmol) of HDAM, 10.78 g (53 mmol) of silylating agent BSA and 114.8 g of NMP were added and stirred for 15 minutes, and then 10.39 g (53 mmol) of CBDA was added and stirred overnight. Thus, a polyamic acid varnish was obtained. The measurement results of the average molecular weight of the obtained polyamic acid varnish are shown in Table 1.

[Comparative Example 7]
A polyimide varnish was obtained in the same manner as in Example 1 except that BCODA was changed to 15.91 g (53 mmol) of TDA. Table 1 shows the measurement results of the average molecular weight and solvent solubility of the obtained polyimide resin.

[Example 6]
The polyimide varnish obtained in Examples 1 to 5 and Comparative Examples 1, 2, and 7 or the polyamic acid varnish obtained in Comparative Examples 4 and 6 was used with a bar coater on a glass substrate, and the dry film thickness was 40 μm. It was applied so that it was dried in a vacuum dryer under a vacuum (degree of vacuum: 10 mmHg or less) at 300 ° C. for 1 hour, cooled to room temperature, peeled off from the glass substrate, and a polyimide molded body (film) was obtained. In addition, the polyimide film created from the polyamic acid varnish of Comparative Example 4 was fragile, and it was difficult to measure each physical property. The polyimide varnish produced from the polyamic acid varnish of Comparative Example 6 was fragile and it was difficult to evaluate mechanical properties. Table 1 shows the measurement results of the linear expansion coefficient, total light transmittance, glass transition temperature, and mechanical properties of the obtained polyimide molded body (film).

  The polyimide resin of the present invention is a polyimide resin having solvent solubility from Table 1, and has an excellent linear expansion coefficient of 60 ppm / K or less, a high total light transmittance of 90% or more, and a high glass transition temperature of 270 ° C. or more. It is clear that it has physical properties.

  In the case of the polyimide resins of Comparative Examples 1 and 2, it can be seen that the glass transition temperature is lower than when BCODA is used. Further, the polyimide resins of Comparative Examples 3 and 5 are insoluble in the solvent, and the polyimide resin of Comparative Example 7 has a total light transmittance of less than 90%, and further has a high linear expansion coefficient and is not suitable for use as a transparent flexible substrate. Conceivable. That is, it can be seen that the polyimide resin of the present invention is a polyimide resin that simultaneously satisfies good solvent solubility, low linear expansion coefficient, high total light transmittance, and high glass transition temperature.

  The polyimide resin of the present invention has both a low coefficient of linear expansion of 60 ppm / K or less, a high glass transition temperature of 270 ° C. or higher, a high total light transmittance of 90% or higher, and solvent solubility. Therefore, the polyimide molded body obtained by molding the polyimide varnish of the polyimide resin can be suitably used for optical materials such as displays and lighting. In addition, the polyimide resin can be used for heat-resistant insulating materials, heat-resistant paints, heat-resistant coating materials, and heat-resistant adhesives.

Claims (9)

General formula (1)
A tetracarboxylic dianhydride represented by:
A solvent-soluble polyimide resin obtained by imidation polymerization reaction of the alicyclic diamine compound with respect to the tetracarboxylic dianhydride 100 in a molar ratio in the range of the alicyclic diamine compound 90 to 110. The polyimide resin of Claim 1 whose alicyclic diamine compound is at least 1 sort (s) represented by the diamine compound of following General formula (2).
  A polyimide varnish containing the polyimide resin according to claim 1 and an organic solvent.   A polyimide molded body obtained by molding the polyimide varnish according to claim 3.   The polyimide molded body according to claim 4, wherein the polyimide molded body is in the form of a film, a film, or a sheet.   The polyimide molded body according to claim 4 or 5, wherein the polyimide molded body has a linear expansion coefficient of 60 ppm / K or lower, a total light transmittance of 85% or higher, and a glass transition temperature of 250 ° C or higher.   The plastic substrate which consists of a polyimide molded body in any one of Claims 4-6.   An electrical component or electronic component comprising the plastic substrate according to claim 7.   A heat-resistant insulating material, heat-resistant paint, heat-resistant coating material, or heat-resistant adhesive using the polyimide resin according to claim 1.