JP4998642B2 - Method for producing polyimide resin - Google Patents

Description

  The present invention provides a cured product having excellent heat resistance, electrical characteristics, mechanical properties, and dimensional stability, and also excellent storage stability before curing, such as various heat resistant coating materials and electrical insulating materials such as printed wiring boards. The present invention relates to a method for producing a polyimide resin used for a thermosetting polyimide resin composition that can be preferably used in the fields of interlayer insulating materials, build-up materials, semiconductor insulating materials, heat-resistant adhesives, and the like.

  In recent years, there has been a demand for improvement in heat resistance, electrical properties, mechanical properties, and storage stability of resins used in various fields mainly in the electrical and electronic industries. Under these circumstances, a thermosetting polyimide resin composition containing a polyimide resin having a linear hydrocarbon structure having a carboxyl group and a number average molecular weight of 300 to 6,000, and an epoxy resin is known in response to the above-mentioned demand. (For example, refer to Patent Document 1). The cured product of the thermosetting polyimide resin composition described in Patent Document 1 has a large coefficient of linear expansion, and therefore is inferior in dimensional stability. In addition, mechanical properties and heat resistance are not sufficient.

          JP 2003-292575 A

  The subject of this invention is the manufacturing method of the polyimide resin used for the thermosetting polyimide resin composition which can obtain the hardened | cured material which is excellent in heat resistance, an electrical property, mechanical property, and dimensional stability, and is excellent also in the storage stability before hardening. Is to provide.

As a result of intensive studies, the present inventor has found the following knowledge.
(1) A cured product obtained by using a resin composition containing a polyimide resin having a structural residue of a phenolic compound, a urethane bond formed by a reaction between a phenolic hydroxyl group and an isocyanate group, and an epoxy resin, Excellent heat resistance, electrical properties, mechanical properties, and dimensional stability.

(2) The resin composition only needs to contain the polyimide resin, and there is no need to use a polyimide resin containing a 300 to 6,000 linear hydrocarbon structure unlike the polyimide resin of Patent Document 1. Therefore, the range of design of the resin composition is expanded.

(3) The resin composition is also excellent in storage stability.

(4) The polyimide resin contained in the resin composition can be easily produced by reacting a polyphenol compound having two or more phenolic hydroxyl groups, a polyisocyanate compound, and an acid anhydride.
The present invention has been completed based on the above findings.

  That is, this invention is a manufacturing method of the polyimide resin which makes the polyphenol compound (a1), polyisocyanate compound (a2), and acid anhydride (a3) which have two or more phenolic hydroxyl groups react, and acid anhydride ( The present invention provides a method for producing a polyimide resin, wherein a3) is ethylene glycol bisanhydro trimellitate.

  The production method of the present invention can provide a cured product having excellent heat resistance and mechanical properties. Moreover, since the cured | curing material obtained using the polyimide resin obtained with the manufacturing method of this invention has a low linear expansion coefficient, it is excellent in dimensional stability. Furthermore, the cured product obtained using the polyimide resin obtained by the production method of the present invention has a low dielectric constant and dielectric loss tangent, and is excellent in electrical characteristics. Therefore, the thermosetting polyimide resin composition obtained by using the polyimide resin obtained by the production method of the present invention can be suitably used for a heat resistant coating material or an electrical insulating material. In addition, the polyimide resin production method of the present invention can easily produce a polyimide resin used in the thermosetting polyimide resin composition.

  It is a production method in which a polyphenol compound (a1) having two or more phenolic hydroxyl groups, a polyisocyanate compound (a2) and an acid anhydride (a3) are reacted, wherein the acid anhydride (a3) is ethylene glycol bisanhydrotri A polyimide resin (A) can be easily obtained by the method for producing a polyimide resin of the present invention which is melitte.

  The polyimide resin (A) has a structure in which an isocyanate group and a phenolic hydroxyl group are linked as a urethane bond as represented by the following general formula (1) and / or the following general formula (2). As the polyimide resin (A), a polyimide resin that dissolves in an organic solvent is particularly preferable because it is easy to handle.

（式中、Ｘは１分子中に２個以上のフェノール性水酸基を有するフェノール系化合物から２個のフェノール性水酸基を除いた残基を示す。）

(In the formula, X represents a residue obtained by removing two phenolic hydroxyl groups from a phenolic compound having two or more phenolic hydroxyl groups in one molecule.)

  Examples of the polyimide resin having the structure represented by the general formula (1) include a polyimide resin having a structure represented by the following general formula (10).

（上記式中Ｒ_ｘ１、Ｒ_ｘ２は同一でも異なっていても良く、ポリイソシアネート化合物から一つのイソシアネート基を除いた残基を示す。）

(In the above formula, R _x1 and R _x2 may be the same or different and represent a residue obtained by removing one isocyanate group from a polyisocyanate compound.)

  Moreover, as a polyimide resin which has a structure represented by the said General formula (2), the polyimide resin etc. which have a structure represented by the following general formula (11) are mentioned, for example.

（上記式中Ｒ_ｘ１はポリイソシアネート化合物から一つのイソシアネート基を除いた残基を示す。）

(In the above formula, R _x1 represents a residue obtained by removing one isocyanate group from the polyisocyanate compound.)

Rx ₁ in the general formula (10) and the general formula (11) may be the same or different.

Here, in the general formula (10), when R _x1 and / or R _x2 correspond to R ₅ of the general formula (9) described later, the general formula (9) was bonded to the general formula (1). It becomes a branched polyimide resin. In the general formula (11), when R _x1 corresponds to R ₅ in the general formula (9) described later, a branched polyimide resin having a structure in which the general formula (2) is bonded to the general formula (9) is obtained.

  Examples of X in the general formula (1) and / or the general formula (2) include the following structures.

As a polyimide resin (A), the polyimide resin which has a structure represented by the said General formula (3) as X of General formula (1) is preferable. Here, R ₁ represented by the general formula (3) represents a single bond or a divalent linking group, and R ₂ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

Examples of R ₁ in the structure represented by the general formula (3) include a single bond, a carbonyl group, a sulfonyl group, a methylene group, an isopropylidene group, a hexafluoroisopropylidene group, an oxo group, a dimethylsilylene group, and a fluorene-9-. And divalent linking groups such as a diyl group and a tricyclo [5.2.1.0 ^2,8 ] decane-diyl group. Moreover, as R < ₂ >, C1-C5 alkyl groups, such as a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, etc. are mentioned, for example.

In the present invention, the carbonyl group is the following structural formula (1a), the sulfonyl group is the following structural formula (1b), the methylene group is the following structural formula (1c), the isopropylidene group is the following structural formula (1d), and hexafluoroisopropylidene. The redene group has the following structural formula (1e), the oxo group has the following structural formula (1f), the dimethylsilylene group has the following structural formula (1g), the fluorene-9-diyl group has the following structural formula (1h), and tricyclo [5.2.1.0]. ^{The 2,8} ] decane-diyl group is represented by the following structural formula (1i), and these are residues of biphenol, tetramethylbiphenol, bisphenol A, bisphenol F, bisphenol S, naphthalenediol, dicyclopentadiene-modified bisphenol and the like. (In the figure, * represents a binding site.) In addition, two hydroxyl groups were removed from a polyphenol compound such as a phenol novolak resin, a cresol novolak resin, a polyphenol resin synthesized from naphthol, alkylphenol, and a formaldehyde condensate. Examples include structural residues.

Among the R _1, a thermosetting polyimide resin composition in which the structure represented by a single bond and the general formula (1b), the general formula (1c), and the general formula (1d) is excellent in solubility and compatibility is obtained. Moreover, since it is easy to synthesize | combine at the time of obtaining a polyimide resin (A), it is preferable. Of the R ₂ , a hydrogen atom and a methyl group are preferable.

  The polyimide resin (A) may have a structure represented by the general formula (1) and / or a structure represented by the general formula (2), and above all, represented by the general formula (1). An imide resin having a structure and a structure represented by the general formula (2) is more preferable. Here, X in the structure represented by the general formula (1) and the structure represented by the general formula (2) may be the same or different.

  The terminal hydroxyl group represented by the general formula (2) is a phenolic hydroxyl group, and this phenolic hydroxyl group is one remaining hydroxyl group other than one hydroxyl group of the polyfunctional phenol compound linked to the resin skeleton by a urethane bond. It is a phenolic hydroxyl group. The polyhydric phenolic hydroxyl group-containing compound used for obtaining the structure represented by the general formula (2) is preferably a bifunctional phenol compound, but in addition to the bifunctional phenol compound, a trifunctional or higher polyphenol compound is used or used in combination. A plurality of phenolic hydroxyl groups may be left at the terminal.

  The polyimide resin having the structure represented by the general formula (2) as the polyimide resin (A) has a phenolic hydroxyl group at the terminal and can be cured by reacting with the epoxy resin (B) described later. . The curing of general phenol compounds and epoxy resins has limitations in terms of glass transition temperature (TG), heat resistance, dielectric properties, mechanical properties, linear expansion, etc., but the structure represented by the general formula (2) Since the polyimide resin having an imide structure in the resin skeleton, it is possible to obtain a cured product having high performance that cannot be obtained by conventional techniques.

  Furthermore, the polyimide resin (A) has a urethane bond structure composed of a phenolic hydroxyl group and an isocyanate group as represented by the general formula (1) or the general formula (2). In general, since the urethane bond between a phenolic hydroxyl group and an isocyanate has a low dissociation temperature, a low-molecular monophenol compound such as phenol or cresol may be used as a blocking agent for the isocyanate group. However, such dissociation of the blocking agent is not preferable because it dissociates in the curing reaction of the coating film or the molded product and leads to generation of bubbles and voids as volatile components. In the present invention, when a phenolic hydroxyl group is introduced using a polyphenol compound having a valence of 2 or more, it remains in the system without being volatilized even when dissociated from the resin under high temperature conditions during curing. The polyimide resin (A) is positively cured by a crosslinking reaction with the epoxy resin. Furthermore, it is considered that the generated isocyanate group further undergoes urethanation reaction with the hydroxyl group produced by the reaction between the phenol and the epoxy, thereby constructing a new crosslinked structure of the molecule and blocking the hydroxyl group which is disadvantageous in dielectric properties. Therefore, the present inventors consider that a network connecting rigid imide structures, which are resin skeletons, is formed by urethane bonds generated, and that good heat resistance or mechanical properties are expressed.

  The polyimide resin (A) is preferably a polyimide resin having an imide bond represented by the following general formula (7) and / or the following general formula (8).

R ₃ in the general formula (7) represents a residue structure obtained by removing an acid anhydride group from a tetracarboxylic acid anhydride. R ₄ in the general formula (8) represents a residue structure obtained by removing an acid anhydride group and a carboxyl group from a tricarboxylic acid anhydride.

R ₃ is a residue obtained by removing the acid anhydride group of the tetracarboxylic acid anhydride. Examples of such a structure include the following structures.

The R ₄ is a residue structure obtained by removing an acid anhydride group and a carboxyl group from a tricarboxylic acid anhydride. Examples of such a structure include the following structures.

  Examples of the polyimide resin having the structure represented by the general formula (7) include a polyimide resin having a structure represented by the following general formula (12).

（上記式中Ｒｘ_１、Ｒｘ_２は同一でも異なっていても良く、ポリイソシアネート化合物から一つのイソシアネート基を除いた残基を示す。）

(In the above formula, Rx ₁ and Rx ₂ may be the same or different and represent a residue obtained by removing one isocyanate group from the polyisocyanate compound.)

In the general formula (12), when Rx ₁ and / or Rx ₂ corresponds to R ₅ in the general formula (9) described later, a branched polyimide having a structure in which the general formula (12) is bonded to the general formula (9). It becomes resin.

  Examples of the polyimide resin having the structure represented by the general formula (8) include a polyimide resin having a structure represented by the following general formula (13).

In the general formula (13), when Rx ₁ and / or Rx ₂ corresponds to R ₅ in the general formula (9) described later, a branched polyimide having a structure in which the general formula (13) is bonded to the general formula (9). It becomes resin.

  Furthermore, the polyimide resin (A) is a polyimide resin branched in the structure represented by the following general formula (9), which improves compatibility with other resin components, improves solvent solubility, and heat resistance of the resulting cured coating film. It is preferable because of good properties.

（式中Ｒ_５はジイソシアネート化合物からイソシアネート基を除いた残基構造を示す。）

(In the formula, R ₅ represents a residue structure obtained by removing an isocyanate group from a diisocyanate compound.)

Examples of R ₅ in the general formula (9) include aromatic residue structures, aliphatic residue structures, and alicyclic residue structures. Among these, those having 4 to 13 carbon atoms can be preferably used. The structure of R ₅ is preferably a combination of two or more structures from the viewpoint of preventing crystallization and improving solubility. In particular, the combined use of an aromatic residue structure and an aliphatic or alicyclic residue structure is preferred.

  Examples of the polyphenol compound (a1) having two or more phenolic hydroxyl groups include hydroquinone, biphenol, tetramethylbiphenol, ethylidene bisphenol, bisphenol A, bisphenol F, bisphenol S, cyclohexylidene bisphenol (bisphenol Z), and dimethyl. Butylidenebisphenol, 4,4 ′-(1-methylethylidene) bis [2,6-dimethylphenol], 4,4 ′-(1-phenylethylidene) bisphenol, 5,5 ′-(1-methylethylidene) bis [1,1′-biphenyl-2-ol], naphthalenediol, dicyclopentadiene-modified bisphenol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and hydroquinone Response product, and the like. Furthermore, as the polyphenol compound (A), a trifunctional or higher functional phenol compound such as a phenol novolac resin or a cresol novolac resin can be used. In addition, in the production method of the polyimide resin of the present invention, the use of a polyphenol compound having three or more functions as the polyphenol compound (A) results in high viscosity of the resin, generation of gelation, etc. It is preferable to use a polyphenol compound containing a phenolic hydroxyl group (a bifunctional polyphenol compound). Of these, bisphenol compounds such as bisphenol A, bisphenol F, and bisphenol S are preferred. Moreover, you may use together monofunctional phenolic compounds, such as a phenol and a cresol, in the range which does not impair the effect of this invention.

  As a polyisocyanate compound (a2) used by this invention, an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, etc. can be used, for example.

  Examples of the aromatic polyisocyanate compound 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, 1,3-bis Aromatic diisocyanates such as (α, α-dimethyl isocyanate methyl) benzene, tetramethylxylylene diisocyanate, diphenylene ether-4,4'-diisocyanate, naphthalene diisocyanate Aromatic Po Resocia sulfonate compounds represented by compounds like.

  Examples of the aliphatic polyisocyanate compound include aliphatic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylenemethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, and norbornylene diisocyanate. Compounds and the like.

  It is also possible to use and use an isocyanate prepolymer obtained by reacting the polyisocyanate compound (a2) and various polyol components in advance with an excess of isocyanate groups.

  The polyimide resin used in the thermosetting polyimide resin composition of the present invention is more preferable because it has a branched structure, so that solvent solubility and compatibility with other resin components such as a curing agent can be improved. As such a branching method, as a part or all of the polyisocyanate compound (a2), for example, a polyisocyanate compound having an isocyanurate ring which is an isocyanurate body alone or in combination with the diisocyanate compound or the like is used and used in combination. Is preferred.

  The polyisocyanate compound having an isocyanurate ring can be obtained, for example, by converting one or more diisocyanate compounds into an isocyanurate in the presence or absence of an isocyanuration catalyst such as a quaternary ammonium salt. And those composed of a mixture of isocyanurates such as trimer, pentamer and heptamer. Specific examples of the isocyanurate form of the polyisocyanate compound include isophorone diisocyanate isocyanurate type polyisocyanate, hexamethylene diisocyanate isocyanurate type polyisocyanate, hydrogenated xylene diisocyanate isocyanurate type polyisocyanate, norbornane diisocyanate isocyanurate type. Aliphatic polyisocyanates such as polyisocyanate, isocyanurate type polyisocyanate of diphenylmethane diisocyanate, isocyanurate type polyisocyanate of tolylene diisocyanate, isocyanurate type polyisocyanate of xylene diisocyanate, isocyanurate type polyisocyanate of naphthalene diisocyanate, etc. .

  As the polyisocyanate compound (a2), when used in combination with a diisocyanate compound and a diisocyanate compound having an isocyanurate ring, an aromatic diisocyanate is used as a diisocyanate compound, an isocyanurate type polyisocyanate of an aliphatic diisocyanate as an isocyanurate type polyisocyanate, and / or It is preferable to use a mixture containing an isocyanurate type polyisocyanate of an alicyclic diisocyanate.

  As the polyisocyanate compound (a2), it is more preferable to use an aliphatic diisocyanate compound because a thermosetting polyimide resin composition having excellent solubility can be obtained and a cured coating film having good electrical characteristics can be obtained.

  Furthermore, the polyisocyanate compound (a2) is used in combination with a polyisocyanate compound other than the above, for example, the diisocyanate compound, a buret body, an adduct body, an allohanate body of the diisocyanate, or a polymethylene polyphenyl polyisocyanate (crude MDI). May be.

  As the polyisocyanate compound (a2) used in the production method of the present invention, a thermosetting polyimide resin composition having good solvent solubility is obtained, and two or more polyisocyanate compounds are used in combination for the reason of breaking crystallinity. It is preferable. In addition, since the cured coating film excellent in heat resistance is obtained, it is preferable to use the isocyanurate body in combination. When using an isocyanurate body together, setting to 70 weight% or less of the total amount of polyisocyanate compound (B) is preferable in terms of preventing high molecular weight and gelation of the resin.

  Examples of the acid anhydride (a3) include an acid anhydride having one acid anhydride group and an acid anhydride having two acid anhydride groups. Examples of the acid anhydride having one acid anhydride group include aromatic tricarboxylic acid anhydrides such as trimellitic anhydride and naphthalene-1,2,4-tricarboxylic acid anhydride.

  Examples of the acid anhydride having two acid anhydride groups include pyromellitic dianhydride, benzophenone-3,3 ', 4,4'-tetracarboxylic 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- , 2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8 -Tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,3,9,10-tetracarboxylic dianhydride , Berylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1 , 1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) ) Propane dianhydride, 2 1,3-bis (3,4-carboxyphenyl) propane dianhydride, bis (3,4-carboxyphenyl) sulfone dianhydride, bis (3,4-carboxyphenyl) ether dianhydride,

Ethylene glycol bisanhydro trimellitate, propylene glycol bis anhydro trimellitate, butanediol bis anhydro trimellitate, hexamethylene glycol bis anhydro trimellitate, polyethylene glycol bis anhydro trimellitate, polypropylene lenglycol bis Anhydro trimellitate and other alkylene glycol bis-an hydroxy trimellitate are listed.

  Among the acid anhydrides (a3), pyromellitic dianhydride, benzophenone-3,3 ', 4,4'-tetracarboxylic dianhydride, diphenyl ether-3,3', 4,4'-tetracarboxylic Acid dianhydride, biphenyl-3,3 ', 4,4'-tetracarboxylic dianhydride, biphenyl-2,2', 3,3'-tetracarboxylic dianhydride, ethylene glycol bisanhydro trimelli Tate is preferred.

  As the acid anhydride (a3), one or more of these can be used. Further, an aromatic tricarboxylic acid anhydride or an aromatic tetracarboxylic acid monoacid anhydride may be mixed with an aromatic tetracarboxylic acid dianhydride.

  A polyimide resin (A) is obtained by reacting a polyphenol compound (a1) having two or more phenolic hydroxyl groups, a polyisocyanate compound (a2), and an acid anhydride (a3) by the method for producing a polyimide resin of the present invention. Can do.

  In the method for producing a polyimide resin of the present invention, the polyphenol compound (a1) and the acid anhydride (a3) react with the polyisocyanate compound (a2). In order to leave the terminal as a phenolic hydroxyl group, the total number of moles of the phenolic hydroxyl group in the polyphenol compound (a1) and the number of moles of the acid anhydride group in the acid anhydride (a3) is the polyisocyanate compound (a2 It is preferable to make it react on the conditions which become larger than the number of moles of the isocyanate group in. As a particularly preferable range, [{number of moles of phenolic hydroxyl group in (a1) + number of moles of acid anhydride group in (a3)} / (a2) in terms of synthesis stability and various performances of the cured product The number of moles of the isocyanate group in the range is from 1 to 10, more preferably from 1.1 to 7. More preferably, (a1) and (a3) are present in an amount of 5% or more, more preferably 10% or more, based on the total weight of the polyphenol compound (a1) and the acid anhydride (a3).

  The method for producing the polyimide resin of the present invention may be produced by a one-step reaction or by a reaction having two or more reaction steps. When the production is carried out by a one-stage reaction, for example, raw materials such as polyphenol compound (a1), polyisocyanate compound (a2) and acid anhydride (a3) are charged in a reaction vessel, and the temperature is increased while stirring. The reaction proceeds while producing carbonic acid. When the production is carried out by a reaction having two or more reaction steps, for example, an acid anhydride (a3) is charged in the presence of the polyisocyanate compound (a2), and an isocyanate group and a polyphenol compound (a1) remaining during or after the reaction. ) To react with the phenolic hydroxyl group. The reaction can also be carried out by charging the polyphenol compound (a1) and the polyisocyanate compound (a2) and charging the acid anhydride (a3) during or after the reaction.

  Further, an acid anhydride (a3) may be charged in the presence of the polyphenol compound (a1), and the isocyanate group remaining during or after the reaction may react with the acid anhydride (a3).

  As reaction conditions, it can be carried out in the range of 50 ° C. to 250 ° C., and it is preferably carried out at a temperature of 70 ° C. to 180 ° C. from the viewpoint of reaction rate and prevention of side reactions.

  In the production method of the present invention, the polyphenol compound (a1) having two or more phenolic hydroxyl groups, the polyisocyanate compound (a2), and the acid anhydride (a3) are converted into (a1), (a2) and (a3). It is preferable to react by using 5 to 50% by weight, 20 to 70% by weight, and 20 to 70% by weight based on the total weight.

  The reaction is preferable because the stability of the resulting polyimide resin is improved when the reaction is performed until almost all isocyanate groups have reacted. Moreover, you may make it react by adding alcohol and a phenol compound with respect to the isocyanate group which remains a little.

  The method for producing a polyimide resin of the present invention is preferable because it can proceed with a uniform reaction using an organic solvent. Here, the organic solvent may be preliminarily present in the system before the chemical reaction or may be introduced in the middle. In order to maintain an appropriate reaction rate during this reaction, the proportion of the organic solvent in the system is preferably 80% by weight or less of the reaction system, more preferably 10 to 70% by weight. As such an organic solvent, since a compound containing an isocyanate group is used as a raw material component, an aprotic polar organic solvent having no active proton such as a hydroxyl group or an amino group is preferable.

  Examples of the aprotic polar organic solvent that can be used include polar organic solvents such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, and γ-butyrolactone. Further, as long as it is soluble, other ether solvents, ester solvents, ketone solvents, petroleum solvents and the like may be used. Various solvents may be mixed and used.

  Examples of the ether solvent include ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl. Polyethylene glycol dialkyl ethers such as ether and triethylene glycol dibutyl ether; ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate and ethylene glycol monobutyl ether acetate; Ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monobutyl ether acetate, polyethylene glycol monoalkyl ether acetates and the like;

Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether; dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol Polypropylene glycol dialkyl ethers such as propylene glycol dibutyl ether; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate; Polypropylene glycol monoalkyl ether acetate such as triglycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, tripropylene glycol monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate Dialkyl ethers of copolymerized polyether glycols such as low molecular weight ethylene-propylene copolymers; monoacetate monoalkyl ethers of copolymerized polyether glycols; alkyl esters of copolymerized polyether glycols; copolymerized polyethers Examples include glycol monoalkyl ester monoalkyl ethers.

  Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of the ketone solvent include acetone, methyl ethyl ketone, and cyclohexanone. Further, as the petroleum solvent, it is also possible to use toluene, xylene, other high-boiling aromatic solvents, and aliphatic and alicyclic solvents such as hexane and cyclohexane.

  The weight average molecular weight of the polyimide resin (A) is preferably 800 to 50,000 because a thermosetting polyimide resin composition having good solvent solubility is obtained and a cured coating film having excellent various physical properties is obtained. 1,000 to 20,000 is more preferable.

  The phenolic hydroxyl group equivalent of the polyimide resin (A) is preferably 400 to 10,000.

  It is preferable that the epoxy resin (B) used for the thermosetting polyimide resin composition obtained by using the polyimide resin obtained by the production method of the present invention has two or more epoxy groups in the molecule. Examples of such epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol S type epoxy resin, and bisphenol F type epoxy resin; novolak types such as phenol novolac epoxy resin, cresol novolac type epoxy resin, and bisphenol type novolak. Epoxy resins; epoxidized products of various dicyclopentadiene-modified phenol resins obtained by reacting dicyclopentadiene with various phenols; biphenyl type epoxy resins such as epoxidized products of 2,2 ', 6,6'-tetramethylbiphenol; Epoxy resin having naphthalene skeleton; aromatic epoxy resin such as epoxy resin having fluorene skeleton and hydrogenated product of these aromatic epoxy resins; neopentyl glycol diglycidyl Aliphatic epoxy resins such as ether and 1,6-hexanediol diglycidyl ether; fats such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and bis- (3,4-epoxycyclohexyl) adipate Cyclic epoxy resins; and heterocyclic ring-containing epoxy resins such as triglycidyl isocyanurate. Among these, an aromatic epoxy resin is preferable because a thermosetting polyimide resin composition excellent in opportunity physical properties of a cured coating film can be obtained.

  The blending amount of the polyimide resin (A) and the epoxy resin curing agent (B) can be used in a ratio of (A) / (B) of 1/100 to 50/1 as a weight ratio of the resin, Preferably, it is 1/10 to 20/1.

  A compound that reacts with the phenolic hydroxyl group of the polyimide resin (A) can be further added to the thermosetting polyimide resin composition of the present invention. Specific examples include epoxy compounds other than the epoxy resin (A), isocyanate compounds, silicates, alkoxysilane compounds, and the like.

  Examples of the isocyanate compound include aromatic isocyanate compounds, aliphatic isocyanate compounds, and alicyclic isocyanate compounds. Preferably, a polyisocyanate compound having two or more isocyanate groups in one molecule is preferable. A blocked isocyanate compound can also be used.

  Thermosetting polyimide resin compositions include polyester resins, polyimide resins, phenoxy resins, PPS resins, PPE resins, polyarylene resins and other binder resins; phenol resins, melamine resins, alkoxysilane curing agents, polybasic acid anhydrides, cyanates Curing agents or reactive compounds such as compounds; melamine, dicyandiamide, guanamine and derivatives thereof, imidazoles, amines, phenols having one hydroxyl group, organic phosphines, phosphonium salts, quaternary ammonium salts, photocationic catalysts, etc. It is also possible to add a curing catalyst and a curing accelerator; further fillers and other additives.

  Further, as the curing accelerator, a urethanization catalyst is preferably used in combination. Examples of such a urethanization catalyst include 1,8-diazabicyclo [5,4,0] undecene-7 (hereinafter referred to as DBU) and its organic salt compounds, dialkyltin alkyls such as triethylenediamine, dibutyltin diacetate, and dibutyltin dilaurate. Examples thereof include esters and carboxylates of bismuth.

  Although there is no limitation in the preparation method of a thermosetting polyimide resin composition, various components may be mixed mechanically, may be mixed by heat melting, or may be mixed after diluting with a solvent.

  The thermosetting polyimide resin composition may further contain various fillers, organic pigments, inorganic pigments, extender pigments, rust inhibitors, and the like as necessary. These may be used alone or in combination of two or more.

  Examples of the filler include barium sulfate, barium titanate, silicon oxide powder, fine particulate silicon oxide, silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica and the like. It is done.

  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.

  The thermosetting polyimide resin composition of the present invention is usually applied to a textile substrate such as an organic or inorganic-metal film substrate or glass cloth or polyaramid cloth by a method such as casting, impregnation or coating. The coating is enforced. The curing temperature is 80 to 300 ° C., and the curing time is 20 minutes to 5 hours.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified.

Example 1
<Manufacture of polyimide resin>
In a flask equipped with a stirrer, a thermometer and a condenser, 140 g of DMAC (dimethylacetamide), 98.4 g (0.24 mol) of TMEG (ethylene glycol bisanhydrotrimellitate), and 40 g of BPS (bisphenol S) ( 0.16 mol), 40 g (0.16 mol) of MDI (diphenylmethane diisocyanate) and 26.9 g (0.16 mol) of HDI (hexamethylene diisocyanate), and while stirring, pay attention to heat generation at 80 ° C. The temperature was raised, the mixture was dissolved and reacted at this temperature for 1 hour, and further heated to 120 ° C. over 2 hours, and then reacted at this temperature for 1 hour. The reaction proceeded with the foaming of carbon dioxide, and the system became a brown liquid. The resin solid content concentration was adjusted to 55% with DMAC to obtain a polyimide resin (X-1) solution having a viscosity at 25 ° C. of 100 Pa · s.

As a result of coating the obtained polyimide resin (X-1) solution on a KBr plate and measuring the infrared absorption spectrum of the sample in which the solvent was volatilized, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, completely disappeared. Characteristic absorption of the imide ring was confirmed at 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ⁻¹ . Further, the amount of carbon dioxide generated was 21.1 g (0.48 mol), which was traced by the change in the weight charged to the flask. From this, it is concluded that a total amount of 0.48 mol of TMEG acid anhydride groups is converted to imide bonds, and the remaining isocyanate groups are linked to the resin by BPS and urethane bonds.

<Preparation of thermosetting polyimide resin composition>
A thermosetting polyimide resin composition 1 was prepared with the formulation shown in Table 1 below. In addition, all the numerical values in a table | surface represent the compounding quantity (weight part) in a solid conversion part.

  Using the obtained thermosetting polyimide resin composition 1, the compatibility, film-forming property, heat resistance, mechanical properties, electrical properties, dimensional stability and storage stability were evaluated according to the following methods. The results are shown in Table 3.

(1) Compatibility Evaluation After the thermosetting polyimide resin composition 1 was prepared, the compatibility state and the prepared thermosetting polyimide resin composition 1 were coated on a glass plate and dried at 120 ° C. The state of the coating film was evaluated according to the following evaluation criteria.
Evaluation Criteria A: In the preparation of the thermosetting polyimide resin composition 1, it becomes uniform easily by stirring, and no foreign matter or the like is seen on the coating surface.
○: In the preparation of the thermosetting polyimide resin composition 1, it becomes uniform by stirring, and no foreign matter or the like is observed on the coating surface.
(Triangle | delta): It is hard to become uniform by stirring in preparation of the thermosetting polyimide resin composition 1, and a foreign material etc. are somewhat seen on the coating-film surface.
X: It does not melt | dissolve uniformly in preparation of the thermosetting polyimide resin composition 1, and a coating film surface can confirm a repelling, a foreign material, and an insoluble matter.

(2) Evaluation of coating film-forming property A test obtained by applying thermosetting polyimide resin composition 1 to a tin plate with an applicator so that the film thickness after drying was 30 μm, followed by drying at 110 ° C. for 30 minutes. The piece was allowed to stand at room temperature for 24 hours, and the appearance of the coating film was evaluated according to the following evaluation criteria.
Evaluation criteria ○: 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.

(3) Evaluation of heat resistance The evaluation of heat resistance was performed by measuring the glass transition point (Tg) of the cured coating film.
<Preparation of test specimen>
The thermosetting polyimide resin composition 1 was coated on a tin plate so that the film thickness after curing was 50 μm, dried for 30 minutes with a dryer at 70 ° C., and then cured at 200 ° C. for 1 hour, respectively. After a coating film was created and cooled to room temperature, the cured coating film was cut out from the coated plate and used as a sample for Tg measurement.

<Tg measurement method>
Using the Tg measurement sample, dynamic viscoelasticity was measured under the following conditions, and the maximum temperature of Tan δ of the obtained spectrum was defined as Tg. It represents that it is a coating film which is excellent in heat resistance, so that the value of Tg is high.
Measuring instrument: Viscoelasticity measuring device RSA-II manufactured by Rheometric
Jig: Tensile test jig Between chucks: 20 mm
Measurement temperature: 25-300 ° C
Measurement frequency: 1Hz
Temperature increase rate: 3 ° C / min

(4) Evaluation of mechanical properties Mechanical properties were evaluated by conducting a tensile test of the coating film.
<Preparation of test piece>
The thermosetting polyimide resin composition 1 was coated on a tin substrate so that the film thickness after curing was 50 μm. Next, this coated plate was dried with a dryer at 70 ° C. for 20 minutes and then cured at 200 ° C. for 1 hour to prepare a cured coating film. After cooling to room temperature, the cured coating film was cut into a predetermined size, isolated from the substrate, and used as a measurement sample.

<Tensile test measurement method>
Five samples for measurement were prepared and subjected to a tensile test under the following conditions to determine the breaking strength and breaking elongation. It represents that it is a coating film which is excellent in mechanical physical property, so that the value of breaking strength and breaking elongation is high.
Measuring instrument: Tensilon manufactured by Toyo Baldwin, Inc. Sample shape: 10 mm x 70 mm
Between chucks: 20 mm
Tensile speed: 10 mm / min
Measurement atmosphere: 22 ° C., 45% RH

(7) Evaluation of electrical characteristics The electrical characteristics were evaluated by measuring the dielectric constant (ε) and dielectric loss (Tanδ) of the coating film.
The thermosetting polyimide resin composition 1 was coated on a tinplate substrate so that the film thickness after curing was 100 μm, dried for 20 minutes with a 70 ° C. drier, then cured at 200 ° C. for 1 hour and cooled, A dielectric sample (ε) and dielectric loss (Tan δ) were measured using a 4291B manufactured by Agilent Technology Co., Ltd., with a frequency of 500 MHz.

(8) Dimensional stability Dimensional stability was evaluated by measuring the linear expansion coefficient of the coating film.
<Preparation of test specimen>
The thermosetting polyimide resin composition 1 was coated on a tinplate substrate so that the film thickness after curing was 50 μm, dried for 20 minutes with a dryer at 70 ° C., then cured at 200 ° C. for 1 hour and cooled, The peeled cured coating film was cut into a width of 5 mm and a length of 30 mm, and used as a measurement sample.

<Method of measuring linear expansion coefficient>
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 49 mN. In addition, the temperature range used for the linear expansion coefficient was calculated | required from the displacement of the sample length in 40-50 degreeC. The smaller the linear expansion coefficient, the better the dimensional stability.

(9) Storage stability (storage stability of thermosetting polyimide resin composition 1)
20 ml of thermosetting polyimide resin composition 1 was placed in a 25 ml glass container and sealed. In this state, the state after standing for 1 week at room temperature was observed.

Example 2 (same as above)
A flask equipped with a stirrer, thermometer and condenser was charged with 156.8 g of DMAC, 65.6 g (0.16 mol) of TMEG, 29.8 g (0.16 mol) of BP (biphenol), and 40 g of MDI (0 .16 mol) and a polyisocyanate having an isocyanurate ring derived from 1,6-hexane diisocyanate (hereinafter abbreviated as HDI-N. Isocyanate group content 23.5%, isocyanurate ring-containing triisocyanate content) 63.3%) 21.4 g (0.12 mol as an isocyanate group) was charged, and the temperature was raised to 100 ° C. with attention to heat generation while stirring, and the mixture was reacted at this temperature for 7 hours. The reaction proceeded with foaming, and the system became a clear brown liquid. A solution of polyimide resin (X-2) having a viscosity at 25 ° C. of 15 Pa · s was obtained.

As a result of coating the obtained polyimide resin (X-2) solution on a KBr plate and measuring the infrared absorption spectrum of the sample in which the solvent was volatilized, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, disappeared completely. Characteristic absorption of the imide ring was confirmed at 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ⁻¹ . Moreover, the characteristic absorption of the isocyanurate ring was confirmed at 1690 cm ⁻¹ and 1460 cm ⁻¹ .

  The amount of carbon dioxide generated was 12.3 g (0.28 mol), which was monitored by the change in the weight charged to the flask. From this, 0.28 mol (87.5%) of the total amount of TMEG acid anhydride groups was converted to imide bonds, and the total amount of MDI and HDI-N isocyanate groups was 0.44 mol. It is concluded that 0.28 mol (63.6%) is converted to an imide bond, and the remaining isocyanate groups are linked to the resin by BP and urethane bonds.

  A thermosetting polyimide resin composition 2 was prepared in the same manner as in Example 1 except that the composition shown in Table 1 was used. Using this, various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 3.

Example 3 (same as above)
A thermosetting polyimide resin composition 3 was prepared in the same manner as in Example 1 except that it was blended according to the blending shown in Table 1. Using this, various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 3.

Example 4 (same as above)
To a flask equipped with a stirrer, a thermometer and a condenser, 184 g of γ-butyrolactone, 82.0 g (0.2 mol) of TMEG, 40.4 g (0.2 mol) of BPF (biphenol F), and TDI (triol) (3) Diisocyanate) 34.8 g (0.2 mol) and a polyisocyanate having an isocyanurate ring derived from 1,6-hexane diisocyanate (hereinafter abbreviated as HDI-N. Isocyanate group content 23.5%, Charge 26.8g (isocyanate group-containing triisocyanate content: 63.3%) (0.15 mol as isocyanate group), raise the temperature to 120 ° C while taking care of heat generation while stirring, and react at this temperature for 7 hours I let you. The reaction proceeded with foaming, and the system became a clear brown liquid. A solution of polyimide resin (X-3) having a viscosity at 25 ° C. of 7 Pa · s was obtained.

As a result of coating the obtained polyimide resin (X-3) solution on a KBr plate and measuring the infrared absorption spectrum of the sample in which the solvent was volatilized, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, completely disappeared. Characteristic absorption of the imide ring was confirmed at 725 cm ⁻¹ , 1780 cm ⁻¹ and 1720 cm ⁻¹ . Moreover, the characteristic absorption of the isocyanurate ring was confirmed at 1690 cm ⁻¹ and 1460 cm ⁻¹ .

  The amount of carbon dioxide gas generated was 15.4 g (0.35 mol), which was monitored by the change in the weight charged to the flask. From this, 0.35 mol (87.5%) of the total amount of TMEG acid anhydride groups was converted to imide bonds, and the total amount of isocyanate groups of TDI and HDI-N was 0.44 mol. It is concluded that 0.55 mol (63.6%) is converted to an imide bond, and the remaining isocyanate groups are linked to the resin by BPF and urethane bonds.

  A thermosetting polyimide resin composition 4 was prepared in the same manner as in Example 1 except that it was blended according to the blending shown in Table 1. Using this, various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 3.

Comparative Example 1 (Synthesis of polyimide resin for comparison)
In a 20-liter flask equipped with a stirrer, a thermometer and a condenser, 4951 g of diethylene glycol monoethyl ether acetate and 2760 g of IPDI-N (isophorone diisocyanate isocyanurate compound, NCO content 18.26%, 12 mol as isocyanate group) , Polytail HA [Mitsubishi Chemical Co., Ltd., hydrogenated liquid polybutadiene having hydroxyl groups at both ends, number average molecular weight 2,100, hydroxyl value 51.2 mg KOH / g] 2191 g (2 mol as hydroxyl group) was charged and stirred. The temperature was raised to 80 ° C. while paying attention to heat generation, and the reaction was carried out for 3 hours. Next, 1536 g of diethylene glycol monoethyl ether acetate and 1536 g (8 mol) of trimellitic anhydride were charged, and the temperature was raised to 160 ° C., followed by reaction for 4 hours. The reaction proceeded with foaming. The system became a light brown clear liquid, and a solution of polyimide resin (X′-1) was obtained.

The infrared absorption spectrum was measured in the same manner as in Synthesis Example 1 except that the obtained polyimide resin (X′-1) solution was used. As a result, 2270 cm ^−1, which is the characteristic absorption of the isocyanate group, disappeared completely, and 725 cm. absorption of imide ring to ^-1 and 1780 cm ^-1 and 1720 cm ^-1, characteristic absorption of isocyanurate ring at 1690 cm ^-1 and 1460 cm ^-1, characteristic absorption of the urethane bond at 1550 cm ^-1. Moreover, the acid value of the polyimide resin was 79 (resin solid content conversion), and the concentration of the isocyanurate ring was 0.66 mmol / g (resin solid content conversion).

  A comparative thermosetting polyimide resin composition 1 ′ was prepared in the same manner as in Example 1 except that the composition shown in Table 2 was used. Using this, various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 4.

Comparative Example 2 and Comparative Example 3
A comparative thermosetting resin composition 2 'and a comparative thermosetting resin composition 3' were prepared in the same manner as in Example 1 except that the composition shown in Table 2 was used. Using this, various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 4.

  As is apparent from the results in Table 3, the cured coating film made of the thermosetting polyimide resin composition of Examples 1 to 4 has a very high Tg, and is a material that can exhibit heat resistance even at high temperatures. I can say that. Furthermore, while having such a high Tg, the dielectric constant and dielectric loss tangent are low, the dielectric properties are good, the mechanical properties are tough, and the linear expansion coefficient is extremely low. Furthermore, the result was excellent in storage stability.

  On the other hand, the cured coating film made of the thermosetting resin composition of Comparative Examples 1 to 3 is lower in breaking strength and breaking elongation than the cured coating film made of the thermosetting polyimide resin composition of the present invention. This was a result, and the linear expansion coefficient was extremely high. The storage stability was also poor.

Claims (4)

  A method for producing a polyimide resin in which a polyphenol compound (a1) having two or more phenolic hydroxyl groups, a polyisocyanate compound (a2), and an acid anhydride (a3) are reacted, wherein the acid anhydride (a3) is ethylene glycol bis A method for producing a polyimide resin, which is anhydrotrimellitate.   The method for producing a polyimide resin according to claim 1, wherein the polyphenol compound (a1) is a polyphenol compound containing two phenolic hydroxyl groups.   The method for producing a polyimide resin according to claim 2, wherein the polyphenol compound (a1) is a bisphenol compound.   The polyphenol compound (a1), the polyisocyanate compound (a2), and the acid anhydride (a3) having two or more phenolic hydroxyl groups, respectively, with respect to the total weight of (a1), (a2), and (a3) The method for producing a polyimide resin according to claim 1, wherein the reaction is carried out so as to be 5 to 50 wt%, 20 to 70 wt%, or 20 to 70 wt%.