JP7375299B2 - Curable imide resin, curable resin composition, method for producing curable imide resin, method for producing curable resin composition, cured product, and method for producing cured product - Google Patents

Description

The present invention relates to a curable imide resin, a curable resin composition, a method for producing a curable imide resin, a method for producing a curable resin composition, a cured product, and a method for producing a cured product.

In recent years, there has been a demand for improvements in the heat resistance, electrical properties, mechanical properties, and storage stability of resins used in various fields, mainly in the electrical and electronic industries.
In response to the above demand, a thermosetting polyimide resin composition containing a polyimide resin having a carboxyl group and a linear hydrocarbon structure and an epoxy resin is known (for example, see Patent Document 1).
However, the polyimide resin described in Patent Document 1 is intended to be used in a thermosetting system with an epoxy resin, and is designed to have a carboxyl group or a carboxylic acid anhydride group at the molecular end. Therefore, the thermosetting polyimide resin composition of Patent Document 1 does not have active energy ray curability suitable for photolithography (photovia).

Japanese Patent Application Publication No. 2003-292575

The present invention relates to a curable imide resin that is curable with active energy rays and capable of forming a highly flexible resin film, a curable resin composition containing such a curable imide resin, a cured product thereof, and a method for producing these. Our goal is to provide the following.

As a result of intensive studies to solve the above problems, the present inventors have discovered a curable imide resin having an ethylenically unsaturated group and a linear structure obtained by reacting a predetermined compound, or such a curable imide resin. They have discovered that by using a curable resin composition containing a photopolymerization initiator, it is possible to form a resin film (cured product) that is curable with active energy rays and has excellent flexibility, and has completed the present invention. reached.

That is, the present invention relates to the following (1) to (19).
(1) The curable imide resin of the present invention is curable by irradiation with active energy rays, and comprises an imide resin (a) having a divalent chain group and two or more carboxylic acid anhydride groups, and the carboxylic acid anhydride group. It is characterized by being reacted with a reactive compound (b) having a reactive group capable of reacting with an acid anhydride group and an ethylenically unsaturated group as essential raw materials.
(2) In the curable imide resin of the present invention, the imide resin (a) is a hydroxyl group-containing compound (a1 ), an isocyanate compound (a2) having two or more isocyanate groups, and an acid anhydride group-containing compound (a3) having two or more of the carboxylic acid anhydride groups as essential raw materials. is preferred.

(3) In the curable imide resin of the present invention, the hydroxyl group-containing compound (a1) is at least one selected from the group consisting of polyolefin polyols, polyether polyols, polycarbonate polyols, polyester polyols, and polysiloxane polyols. is preferred.
(4) In the curable imide resin of the present invention, the isocyanate compound (a2) is toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane Preferably, it is at least one selected from the group consisting of diisocyanate and isophorone diisocyanate.

(5) In the curable imide resin of the present invention, the acid anhydride group-containing compound (a3) is preferably a tetracarboxylic dianhydride.
(6) In the curable imide resin of the present invention, the tetracarboxylic dianhydride is pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, 3, 3'-4,4'-diphenylsulfonetetracarboxylic dianhydride and 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1 , 2-C]furan-1,3-dione.

(7) In the curable imide resin of the present invention, the reactive group of the reactive compound (b) is preferably a hydroxyl group.
(8) In the curable imide resin of the present invention, the ethylenically unsaturated group of the reactive compound (b) is preferably a (meth)acryloyl group.
(9) The curable imide resin of the present invention preferably has an acid value of 10 to 150 mgKOH/g in terms of solid content.
(10) The curable imide resin of the present invention preferably has a number average molecular weight of 400 to 20,000.

(11) The curable resin composition of the present invention is characterized by containing the curable imide resin and a photopolymerization initiator.
(12) The curable resin composition of the present invention preferably further contains a curing agent.
(13) In the curable resin composition of the present invention, the curing agent is preferably an epoxy resin.
(14) In the curable resin composition of the present invention, the epoxy resin is preferably a novolac type epoxy resin.
(15) In the curable resin composition of the present invention, the epoxy resin preferably has a softening point of 50 to 120°C.

(16) The method for producing a curable imide resin that can be cured by irradiation with active energy rays according to the present invention comprises: an imide resin (a) having a divalent chain group and two or more carboxylic acid anhydride groups; It is characterized by having a step of reacting a reactive compound (b) having a reactive group capable of reacting with a carboxylic acid anhydride group and an ethylenically unsaturated group as an essential raw material.
(17) The method for producing a curable resin composition of the present invention is characterized by having a step of blending the curable imide resin and a photopolymerization initiator.
(18) The cured product of the present invention is characterized in that it is obtained by curing the curable resin composition.
(19) The method for producing a cured product of the present invention is characterized by having a step of curing the curable resin composition.

According to the present invention, since it has an ethylenically unsaturated group and a divalent chain group, it has active energy ray curability and can form a resin film (cured film) with excellent flexibility; A curable resin composition and a cured product with excellent flexibility can be obtained. Moreover, according to the present invention, a curable imide resin, a curable resin composition, and a cured product can be efficiently produced.

Hereinafter, the curable imide resin, the curable resin composition, the method for producing the curable imide resin, the method for producing the curable resin composition, the cured product, and the method for producing the cured product of the present invention will be described based on preferred embodiments. Explain in detail.
The method for producing a curable imide resin of the present invention comprises: an imide resin (a) having a divalent chain group and two or more carboxylic anhydride groups; a reactive group capable of reacting with the carboxylic anhydride group; It has a step of reacting a reactive compound (b) having an ethylenically unsaturated group as an essential raw material.
Therefore, the curable imide resin (i.e., the curable imide resin of the present invention) obtained by reacting the imide resin (a) and the reactive compound (b) as essential raw materials has a relatively long chain structure and a molecular It has a terminal ethylenically unsaturated group.
Such amide-imide resins and curable resin compositions containing the same can be used for various heat-resistant coating materials and electrical insulation materials, such as interlayer insulation materials for printed wiring boards, build-up materials, solder resist materials, coverlay film materials, and prepreg impregnated materials. It is suitably used as an insulating material for semiconductor devices, a sealing material for semiconductor devices (mold underfill material), a heat-resistant adhesive, and the like.

Due to the above structure, the curable imide resin of the present invention has a relatively long chain structure (i.e., soft segment), so a resin film formed using a curable resin composition containing it has high flexibility. has.
Moreover, since the curable imide resin of the present invention has an ethylenically unsaturated group at the molecular end, it can be cured by irradiation with active energy rays. That is, the curable imide resin of the present invention has active energy ray curability. Therefore, by using the curable resin composition of the present invention, a resin film microfabricated by photolithography can be formed.
Here, in this specification, the molecular ends refer to both ends of the polymer chain (main chain) of the curable imide resin, and when the polymer chain has a branched structure, each end of the main chain and side chain. say about. Therefore, the ethylenically unsaturated group in the present invention does not include an ethylenically unsaturated group that is directly bonded to a carbon atom forming the main chain (for example, a carbon atom of a benzene ring, etc.) in the middle of the main chain.

（Ｒ_１は、水酸基含有化合物（ａ１）の残基（２価の鎖状基）であり、Ｒ_２は、イソシアネート化合物（ａ２）の残基であり、Ｒ_３は、カルボン酸無水物基を有する酸無水物基含有化合物（ａ３）の残基であり、ｌ，ｍおよびｎは、それぞれ独立して、０～１５の整数であり、ｌ及びｎのいずれか一方は、０ではない。）
かかる構造のイミド樹脂（ａ）では、２個のウレタン結合同士の間に、２価の鎖状基が位置する構造を有するため、柔軟性が高く、よって、得られる樹脂膜の柔軟性も高くなる。 The imide resin (a) has a divalent chain group and two or more hydroxyl groups, and a hydroxyl group-containing compound (a1) having a number average molecular weight of 200 to 5,000, and two or more isocyanate groups. A compound obtained by reacting an isocyanate compound (a2) with an acid anhydride group-containing compound (a3) having two or more carboxylic acid anhydride groups as essential raw materials is preferred. Examples of such imide resin (a) include a compound represented by the following (Formula 1).

(R ₁ is a residue (bivalent chain group) of a hydroxyl group-containing compound (a1), R ₂ is a residue of an isocyanate compound (a2), and R ₃ is a residue of a carboxylic acid anhydride group) (l, m and n are each independently an integer of 0 to 15, and either l or n is not 0.)
The imide resin (a) having such a structure has a structure in which a divalent chain group is located between two urethane bonds, so it has high flexibility, and therefore the resulting resin film also has high flexibility. Become.

The hydroxyl group-containing compound (a1) has a divalent chain group and is a component used for the purpose of imparting flexibility to the curable imide resin (resin film).
The divalent chain group may have a linear structure or a branched structure as long as it can impart flexibility to the curable imide resin. Examples of the divalent chain group include saturated or unsaturated structures containing carbon atoms, hydrogen atoms, oxygen atoms, hydrogen atoms, silicon atoms, and the like.
The number average molecular weight of the hydroxyl group-containing compound (a1) may be about 200 to 5,000, but preferably about 800 to 3,000. By using the hydroxyl group-containing compound (a1) having such a number average molecular weight, it is possible to impart sufficiently high flexibility to the resin film and also increase the mechanical strength of the resin film.
Note that the glass transition temperature (Tg) of the hydroxyl group-containing compound (a1) is preferably 0°C or lower, more preferably about -150 to 0°C. It is preferable that the Tg of the hydroxyl group-containing compound (a1) be within the above range from the viewpoint that the resin film (cured film) can be designed to have high flexibility.

The hydroxyl group-containing compound (a1) is preferably at least one selected from the group consisting of polyolefin polyols, polyether polyols, polycarbonate polyols, polyester polyols, and polysiloxane polyols. By using these hydroxyl group-containing compounds (a1), the flexibility of the resin film can be further improved.
Further, as the hydroxyl group-containing compound (a1), polyols having a copolycondensation structure of two or more of the above polyols can also be used.
Examples of the polyolefin polyol include polyol compounds having a polyolefin structure or a polydiene structure. Specific examples of polyolefin polyols include polyethylene polyols, polypropylene polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, polyisoprene polyols, hydrogenated polyisoprene polyols, and the like.
Examples of the polyether polyol include polyalkylene ether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polybutylene glycol, and copolymers of these polyalkylene polyols.

Examples of polycarbonate polyols include polyalkylene carbonate polyols obtained from propylene diol, butanediol, pentanediol, hexanediol, methylpentanediol, cyclohexanedimethanol, etc., and alkylene oxide addition diols such as bisphenol A, F, and S. Examples include the obtained polycarbonate polyols and copolymers of these polyols.
Examples of the polyester polyol include esterified products of alkylene diol and polyvalent carboxylic acid, transesterified products of polyvalent carboxylic acid with alkyl ester, polylactone polyols such as ε-caprolactone polylactone polyol, and the like.
Examples of the polysiloxane polyol include dimethylpolysiloxane polyol, methylphenylpolysiloxane polyol, and the like.

The hydroxyl group-containing compound (a1) is preferably a polyolefin polyol or polysiloxane polyol if you want to improve the dielectric properties of the resin film, and if you want to improve the physical properties and hydrolysis resistance of the resin film. , polycarbonate polyol is preferable, and when it is desired to improve the flexibility of the resin film, polyolefin polyol is preferable.
Considering ease of synthesis, the hydroxyl group-containing compound (a1) is preferably a polyol having 1 to 4 hydroxyl groups, and more preferably a polyol (diol) having 2 hydroxyl groups.
Examples of the diol include polyolefin diol, polyether diol, polycarbonate diol, polyester diol, polysiloxane diol, etc., but polybutadiene diol and/or hydrogenated polybutadiene diol are preferred. By using such a diol, it is easy to form a resin film with good various physical properties.
In addition, polybutadiene diol or hydrogenated polybutadiene diol includes G-1000, G-3000, GI-1000, GI-3000 (all manufactured by Nippon Soda Co., Ltd.), R-45EPI (manufactured by Idemitsu Petrochemical Co., Ltd.), etc. can be used.

The isocyanate compound (a2) is a component used for the purpose of improving the solubility of the curable imide resin in general-purpose solvents, and is preferably 70% by mass or more of the total isocyanate raw material. Moreover, from the viewpoint of suppressing crystallization of the curable imide resin over time during the reaction, it is more preferable that the isocyanate compound (a2) accounts for 80% by mass or more of the total isocyanate raw material.
Examples of such isocyanate compounds (a2) include aromatic isocyanate compounds, aliphatic isocyanate compounds, and the like.

Examples of aromatic isocyanate compounds include phenylene diisocyanate (p-phenylene diisocyanate, m-phenylene diisocyanate), xylene diisocyanate (p-xylene diisocyanate, m-xylene diisocyanate), toluene diisocyanate (toluene-2,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,4-diisocyanate, toluene diisocyanate). 2,6-diisocyanate), 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 3,3'-diethyldiphenyl-4,4'-diisocyanate, m-xylene diisocyanate, Examples include 1,3-bis(α,α-dimethylisocyanatomethyl)benzene, tetramethylxylylene diisocyanate, diphenylene ether-4,4'-diisocyanate, naphthalene diisocyanate, and the like.

Examples of aliphatic isocyanate compounds include hexamethylene diisocyanate, lysine diisocyanate, trimethylhexane diisocyanate, isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate (HXDI), norbornene diisocyanate (NBDI), etc. Can be mentioned.
Among them, as the isocyanate compound (a2), toluene-2,4-diisocyanate (2,4-tolylene diisocyanate), toluene-2,6-diisocyanate (2,6-tolylene diisocyanate), hexamethylene diisocyanate, xylylene diisocyanate, Preferably, it is at least one selected from the group consisting of isocyanate, 4,4'-diphenylmethane diisocyanate, and isophorone diisocyanate. By using these isocyanates, the solubility of the curable imide resin in general-purpose solvents can be further improved.

Further, as the isocyanate compound (a2), an isocyanate prepolymer obtained by reacting the above diisocyanate and various polyol components in advance with an excess amount of isocyanate groups can be used alone or in combination.
It is preferable for the curable imide resin to have a branched structure because it improves solvent solubility and compatibility with other resin components (curing agent, etc.).
Methods for creating a branched structure in a curable imide resin include the use alone of a trifunctional or higher-functional isocyanurate-type polyisocyanate having an isocyanurate ring, which is an isocyanurate form of diisocyanate, or the use of an isocyanurate-type polyisocyanate and other polyisocyanates. Examples include the use of mixtures with isocyanates.
The isocyanurate-type polyisocyanate is, for example, a trimer obtained by isocyanurating at least one of the above diisocyanates in the presence or absence of an isocyanurating catalyst such as a quaternary ammonium salt. , pentamer, heptamer, and the like.

Specific examples of the isocyanurate form of the above diisocyanate include isocyanurate type polyisocyanate of isophorone diisocyanate (IPDI3N), isocyanurate type polyisocyanate of hexamethylene diisocyanate (HDI3N), isocyanurate type polyisocyanate of hydrogenated xylene diisocyanate ( Aliphatic polyisocyanates such as isocyanurate type polyisocyanate (NBDI3N) of norbornene diisocyanate, isocyanurate type polyisocyanate of diphenylmethane diisocyanate, isocyanurate type polyisocyanate of tolylene diisocyanate, and isocyanurate type polyisocyanate of xylene diisocyanate. Examples include aromatic polyisocyanates such as polyisocyanates and isocyanurate-type polyisocyanates such as naphthalene diisocyanate.

As the isocyanate compound (a2), when used in combination with diisocyanate and isocyanurate type polyisocyanate, aromatic diisocyanate as diisocyanate and isocyanurate type polyisocyanate and/or alicyclic diisocyanate of aliphatic diisocyanate as isocyanurate type polyisocyanate. It is preferred to use a mixture of isocyanurate-type polyisocyanates.
It is preferable to use an aliphatic diisocyanate because a curable imide resin with excellent solubility can be obtained and a resin film (cured film) with good electrical properties can be obtained. Among the aliphatic diisocyanates, it is preferable to use trimethylhexane diisocyanate because a resin film with excellent flexibility can be obtained.

The acid anhydride group-containing compound (a3) imparts reactivity to the imide resin (a) with the reactive compound (b), and also forms an imide bond to impart excellent heat resistance to the curable imide resin. It is an ingredient used for such purposes.
The acid anhydride group-containing compound (a3) is preferably a compound having two carboxylic anhydride groups (ie, tetracarboxylic dianhydride) because it is relatively easily available.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride (benzophenone-3,3',4,4'-tetracarboxylic dianhydride), diphenyl ether-3, 3',4,4'-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride (biphenyl-3,3',4,4 '-tetracarboxylic dianhydride, biphenyl-2,2',3,3'-tetracarboxylic dianhydride, biphenyl-2,3,3',4-tetracarboxylic dianhydride), naphthalenetetracarboxylic dianhydride Acid dianhydride (naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetra carboxylic dianhydride), decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1, 2,5,6-tetracarboxylic dianhydride, oxydiphthalic anhydride, P-phenylene bis(trimelitate anhydride), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, dichloronaphthalenetetracarboxylic dianhydride Anhydride (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(dicarboxyphenyl)methane dianhydride (bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride) , bis(dicarboxyphenyl)ethane dianhydride (1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride) , bis(dicarboxyphenyl)propane dianhydride (2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,3-bis(3,4-dicarboxyphenyl)propane dianhydride) , bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-cyclohexene- 1,2-dicarboxylic anhydride, cyclobutanetetracarboxylic anhydride, cyclopentanetetracarboxylic anhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4 , 5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bisanhydrotrimellitate, propylene glycol Examples include bisanhydrotrimellitate, butanediol bisanhydrotrimellitate, hexamethylene glycol bisanhydrotrimellitate, polyethylene glycol bisanhydrotrimellitate, polypropylene glycol bisanhydrotrimellitate, and the like.

Among them, the acid anhydride group-containing compound (a3) includes pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic anhydride, P-phenylene bis(trimellitate anhydride), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, cyclobutanetetracarboxylic anhydride, cyclopentanetetracarboxylic anhydride, 3,3'-4,4' -Diphenylsulfonetetracarboxylic dianhydride and 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan- Preferably, it is at least one selected from the group consisting of 1,3-diones.
In addition, these tetracarboxylic dianhydrides may be used individually by 1 type, or may use 2 or more types together. Further, as the acid anhydride group-containing compound (a3), an aromatic tricarboxylic acid anhydride or an aromatic tetracarboxylic acid monoanhydride may be mixed with the aromatic tetracarboxylic dianhydride.

When producing the imide resin (a), the hydroxyl group-containing compound (a1) and the acid anhydride group-containing compound (a3) react with the isocyanate compound (a2), respectively.
In order to make the carboxylic acid anhydride group remain at the molecular terminal of the curable imide resin of the present invention, the number of moles m (a1) of hydroxyl groups in the hydroxyl group-containing compound (a1) and the number m (a1) of hydroxyl groups in the acid anhydride group-containing compound (a3) are determined. It is preferable to carry out the reaction under conditions such that the total amount of carboxylic acid anhydride groups in the isocyanate compound (a2) is in excess of the number of moles of isocyanate groups m(a2) in the isocyanate compound (a2).
As a particularly preferable range, [{m(a1)+m(a3)}/m(a2)] is preferably about 1 to 10 from the viewpoint of improving synthetic stability and various performances of the resulting resin film. , more preferably about 1.1 to 7.
Further, it is more preferable that m(a1), m(a2) and m(a3) are each 5% or more with respect to the total of m(a1), m(a2) and m(a3), More preferably, it is 10% or more.

It is preferable to carry out the reaction until almost all of the isocyanate groups have disappeared because the resulting imide resin (a) has good stability. Further, an alcohol compound, a phenol compound, an oxime compound, etc. may be added to and reacted with some remaining isocyanate groups.
The imide resin (a) may be synthesized in one stage of reaction, or may be synthesized in two or more stages of reaction.
When synthesizing in a one-stage reaction, for example, raw materials such as a hydroxyl group-containing compound (a1), an isocyanate compound (a2), an acid anhydride group-containing compound (a3), etc. are charged into a reaction vessel and heated while stirring. The imide resin (a) can be synthesized by performing an imidization reaction and a urethanization reaction.
On the other hand, in the case of synthesis using two or more stages of reaction, it can be carried out, for example, by methods ``1'' to ``3'' below.

1. The isocyanate compound (a2) and the acid anhydride group-containing compound (a3) are charged (mixed), and during or after the imidization reaction, the remaining isocyanate group and the hydroxyl group of the hydroxyl group-containing compound (a1) are combined. Method of performing urethanization reaction 2. The hydroxyl group-containing compound (a1) and the isocyanate compound (a2) are charged (mixed), and the remaining isocyanate group and the carboxylic anhydride of the acid anhydride group-containing compound (a3) are mixed during or after the urethanization reaction. Method of performing an imidization reaction with a physical group 3. A method in which a hydroxyl group-containing compound (a1) and an acid anhydride group-containing compound (a3) are charged (mixed), and then an isocyanate compound (a2) is added to perform a urethanization reaction and an imidization reaction.

The reaction temperature when reacting the hydroxyl group-containing compound (a1), the isocyanate compound (a2), and the acid anhydride group-containing compound (a3) is preferably about 50 to 250°C, and about 70 to 180°C. It is more preferable. By setting the reaction temperature within this range, it is possible to sufficiently increase the reaction rate of the raw material components while suppressing the occurrence of side reactions.
When carrying out the above reaction, it is preferable to use an organic solvent because the reaction can proceed uniformly. Here, the organic solvent may be supplied into the reaction system in advance before starting the reaction, or may be supplied into the reaction system during the reaction.
In addition, in order to maintain an appropriate reaction rate, the proportion of the organic solvent contained in the reaction system is preferably 80% by mass or less, more preferably about 10 to 70% by mass. .
Since the isocyanate compound (a2) is used as a raw material component, the organic solvent is preferably a polar organic solvent (aprotic polar organic solvent) that does not have active protons such as hydroxyl groups or amino groups. Examples of such aprotic polar organic solvents include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, sulfolane, and γ-butyrolactone.
Further, as the organic solvent, other ether solvents, ester solvents, ketone solvents, petroleum solvents, etc. may be used as long as they can dissolve the raw material components. Further, the organic solvent may be a mixture of the various solvents mentioned above.

Examples of ether solvents 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 ether. , polyethylene glycol dialkyl ethers such as triethylene glycol dibutyl ether; ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate; diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl Polyethylene glycol monoalkyl ether acetates such as ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monobutyl ether acetate; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol Propylene glycol dialkyl ethers such as dibutyl ether; polypropylene glycol dialkyl ethers such as dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol dibutyl ether, etc. Propylene glycol monoalkyl ether acetate such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate; Dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate , polypropylene glycol monoalkyl ether acetates such as tripropylene glycol monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate; dialkyl of copolymerized polyether glycol such as low molecular weight ethylene-propylene copolymer Ethers; monoacetate monoalkyl ethers of copolymerized polyether glycol; alkyl esters of copolymerized polyether glycol; monoalkyl ester monoalkyl ethers of copolymerized polyether glycol, and the like.

Examples of the ester solvent include ethyl acetate, butyl acetate, and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and cyclohexanone.
Further, as the petroleum solvent, for example, toluene, xylene, other high boiling point aromatic solvents, and aliphatic or alicyclic solvents such as hexane and cyclohexane can be used.

When synthesizing the imide resin (a), the imidization reaction may proceed by using various imidization catalysts.
Examples of imidization catalysts include tertiary catalysts such as tetramethylbutanediamine, benzyldimethylamine, triethanolamine, triethylamine, N,N'-dimethylpiperidine, α-methylbenzyldimethylamine, N-methylmorpholine, and triethylenediamine. Examples include organometallic catalysts such as amines, dibutyltin laurate, dimethyltin dichloride, cobalt naphthenate, and zinc naphthenate. In addition, these catalysts may be used individually by 1 type, or may use 2 or more types together.
Among these, triethylenediamine is preferred as the imidization catalyst.

In the urethanization/imidization reaction, a hydroxyl group or a carboxylic acid anhydride group and an isocyanate group form a urethane bond or an imide bond. The progress of the urethanization/imidization reaction can be tracked by analytical means such as infrared spectroscopy, acid value, and quantitative determination of isocyanate groups.
For example, in an imidization reaction, in the infrared spectrum, the absorption peak at 2270 cm ^-1 , which is the characteristic absorption of isocyanate groups, decreases with the reaction, and carboxylic acid anhydride, which has characteristic absorptions at 1860 cm ^-1 and 850 cm ^-1 , The absorption peak of the group decreases. On the other hand, the absorption peaks of imide bonds increase at 1770 cm ^-1 and 1720 cm ^-1 .

The urethanization reaction/imidization reaction can be carried out while checking the desired acid value, viscosity, molecular weight, etc. By adjusting the amounts of the hydroxyl group-containing compound (a1), the isocyanate compound (a2), and the acid anhydride group-containing compound (a3) and performing the urethanization reaction/imidization reaction, a carboxylic acid anhydride group is added to the molecule end. An imide resin (a) having the following is obtained.
Thereafter, the imide resin ( The curable imide resin of the present invention is obtained by introducing an ethylenically unsaturated group into the molecular terminal of a).

Examples of the reactive group capable of reacting with the carboxylic acid anhydride group of the imide resin (a) include a hydroxyl group, an epoxy group, an oxetanyl group, an amino group, an isocyanate group, and a hydroxyl group is preferred. If the reactive group is a hydroxyl group, an ethylenically unsaturated group and a carboxyl group are introduced into the molecular terminal of the imide resin (a) by reaction with the carboxylic acid anhydride group of the imide resin (a), and sealing is performed. can be stopped.
Therefore, the obtained curable imide resin has active energy ray curability and thermosetting properties. Further, by having a carboxyl group, the curable imide resin also has alkali developability, and the curable imide resin and curable resin composition of the present invention can be suitably used as a material for photolithography. I can do it.

On the other hand, the ethylenically unsaturated group may be any group that can be polymerized by irradiation with active energy rays, such as (meth)acryloyl group, vinyl group, vinyloxy group, etc., but it must be a (meth)acryloyl group. is preferred. This is because the (meth)acryloyl group undergoes a rapid polymerization reaction when irradiated with various active energy rays.
Here, active energy rays refer to energy rays such as ultraviolet rays, electron beams, and infrared rays that can generate substances that trigger polymerization reactions, such as radicals, cations, and anions. Among these, ultraviolet rays are preferred as active energy rays because relatively inexpensive equipment can be used.
Examples of light sources that irradiate ultraviolet rays include high-pressure mercury lamps, metal halide lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, and ultraviolet lasers.

Specific examples of the reactive compound (b) include 2-hydroxyethyl (meth)acrylate, pentaerythritol tri(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl (meth) in which the reactive group is a hydroxyl group. ) acrylate, bis(acryloxyethyl)isocyanurate, trimethylolpropane di(meth)acrylate, dipentaerythritol penta(meth)acrylate, and the like.
The number of moles (X) of carboxylic acid anhydride groups contained in the imide resin (a) and the number of moles (Y) of reactive groups contained in the reactive compound (b) satisfy the following formula: It is preferable. That is, it is preferable to satisfy 2>((Y)/(X))>0.6, and more preferably to satisfy 1.3>((Y)/(X))>0.8. By using the reactive compound (b) in such an amount, the yield of the curable imide resin can be sufficiently increased.

The reaction temperature is preferably about 30 to 230°C, more preferably about 50 to 160°C. If the sealing reaction is carried out in such a temperature range, it is easy to set an appropriate reaction rate while preventing the occurrence of side reactions, decomposition, etc.
The progress of this sealing reaction can also be tracked by analytical means such as infrared spectroscopy and quantitative determination of carboxylic acid anhydride groups.
Further, the sealing reaction may be terminated by adding a reaction terminator or lowering the temperature while checking the desired acid value, viscosity, molecular weight, etc.
Note that during and after the reaction, catalysts, antioxidants, surfactants, other solvents, etc. may be added to the extent that the physical properties of the curable imide resin are not impaired.

The curable imide resin of the present invention preferably has an acid value of about 10 to 150 mgKOH/g in terms of solid content, more preferably about 20 to 100 mgKOH/g in terms of solid content. A curable imide resin having such an acid value can exhibit excellent cured physical properties. Note that the acid value is the number of mg of potassium hydroxide (KOH) required to neutralize the carboxyl groups present in 1 g of the curable imide resin skeleton, and is a value expressed in mgKOH/g.
Further, the number average molecular weight of the curable imide resin of the present invention is preferably about 400 to 20,000, more preferably about 500 to 15,000. A curable imide resin having such a number average molecular weight is preferable because it maintains high flexibility and exhibits high solubility in various general-purpose solvents. The number average molecular weight (Mn) is a value determined by gel permeation chromatography (GPC) using polystyrene of known molecular weight as a standard.

（Ｒ_１、Ｒ_２、Ｒ_３、１、ｍ及びｎは、それぞれ上記と同一であり、Ａｃは、（メタ）アクリロイル基を含有する１価の有機基である。） An example of such a curable imide resin is a compound represented by the following (Formula 2).

(R ₁ , R ₂ , R ₃ , 1, m and n are each the same as above, and Ac is a monovalent organic group containing a (meth)acryloyl group.)

Such a curable imide resin has a polar group such as a (meth)acryloyl group or a carboxyl group. Therefore, when a resin film is formed on a metal base material (for example, a copper base material), the resin film comes into contact with (bonds to) the metal base material via the polar group at the end of the molecule. Therefore, the resin film also exhibits high adhesion to the metal base material.
Furthermore, as described above, the curable imide resin has active energy ray curability and thermosetting properties, and thus exhibits excellent properties (cured physical properties). In addition, the resulting resin film (cured film) has an increased crosslinking density and thus has improved mechanical strength.

Since the curable imide resin of the present invention has active energy ray curability, it can be used as a curable resin composition, for example, by adding a photopolymerization initiator. The method for producing a curable resin composition of the present invention includes a step of blending a curable imide resin and a photopolymerization initiator.
The photopolymerization initiator can be appropriately selected and used depending on the type of active energy ray to be irradiated. Further, the photopolymerization initiator may be used in combination with a photosensitizer such as an amine compound, a urea compound, a sulfur-containing compound, a phosphorus-containing compound, a chlorine-containing compound, or a nitrile compound.
Specific examples of photopolymerization initiators include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino) -2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 4'-(methylthio)-α-morpholino-α-methylpropiophenone, etc. Alkylphenone photopolymerization initiators; acylphosphine oxide photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; intramolecular hydrogen abstraction type photopolymerization initiators such as benzophenone compounds, etc. It will be done. These compounds may be used alone or in combination of two or more.

Commercially available photopolymerization initiators include, for example, "IRGACURE127", "IRGACURE184", "IRGACURE250", "IRGACURE270", "IRGACURE290", "IRGACURE369E", "IRGACURE379EG", and "IRGACURE379EG" manufactured by BASF. IRGACURE500”, “IRGACURE651” , "IRGACURE754", "IRGACURE819", "IRGACURE907", "IRGACURE1173", "IRGACURE2959", "IRGACURE MBF", "IRGACURE TPO", "IRGACURE OXE 01", "IRGACURE OXE 02", "OMNIRAD184" manufactured by IGM RESINS , "OMNIRAD250", "OMNIRAD369", "OMNIRAD369E", "OMNIRAD651", "OMNIRAD907FF", "OMNIRAD1173", etc.

The amount of the photopolymerization initiator added is preferably about 0.05 to 15% by mass, and 0.1 to 15% by mass, based on the total amount of components other than the solvent (total amount of solid components) of the curable resin composition. More preferably, it is about 10% by mass.
The curable resin composition of the present invention may contain resin components other than the curable imide resin. Examples of this resin component include various (meth)acrylate monomers.
Examples of acrylate monomers include mono(meth)acrylate or a modified product thereof, di(meth)acrylate or a modified product thereof, tri(meth)acrylate or a modified product thereof, poly(meth)acrylate with four or more functional groups or a modified product thereof, etc. Can be mentioned. These acrylates or modified products thereof may be used alone or in combination of two or more.

Specific examples of mono(meth)acrylate or modified products thereof include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, and hexyl(meth)acrylate. ) acrylate, aliphatic mono(meth)acrylates such as 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate; aliphatic mono(meth)acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl mono(meth)acrylate Formula mono(meth)acrylates; heterocyclic mono(meth)acrylates such as glycidyl(meth)acrylate, tetrahydrofurfuryl acrylate; benzyl(meth)acrylate, phenyl(meth)acrylate, phenylbenzyl(meth)acrylate, phenoxy( meth)acrylate, phenoxyethyl(meth)acrylate, phenoxyethoxyethyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, phenoxybenzyl(meth)acrylate, benzylbenzyl(meth)acrylate, phenylphenoxyethyl( Aromatic mono(meth)acrylates such as meth)acrylates; poly(poly)oxyethylene chains, (poly)oxypropylene chains, and (poly)oxytetramethylene chains in the molecular structure of the above mono(meth)acrylates; Examples include (poly)oxyalkylene-modified mono(meth)acrylates into which an oxyalkylene chain is introduced; lactone-modified mono(meth)acrylates into which a (poly)lactone structure is introduced into the molecular structure of the above-mentioned mono(meth)acrylates.

Specific examples of di(meth)acrylate or modified products thereof include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, neo Aliphatic di(meth)acrylates such as pentyl glycol di(meth)acrylate; 1,4-cyclohexanedimethanol di(meth)acrylate, norbornane di(meth)acrylate, norbornane dimethanol di(meth)acrylate, dicyclopenta Cycloaliphatic di(meth)acrylates such as nil di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate; aromatic di(meth)acrylates such as biphenol di(meth)acrylate, bisphenol di(meth)acrylate; ) Acrylate; Polyoxyalkylene in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, (poly)oxypropylene chain, or (poly)oxytetramethylene chain is introduced into the molecular structure of the above di(meth)acrylate. Modified di(meth)acrylate; Examples include lactone-modified di(meth)acrylate in which a (poly)lactone structure is introduced into the molecular structure of the above di(meth)acrylate.

Specific examples of tri(meth)acrylates or modified products thereof include aliphatic tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate and glycerin tri(meth)acrylate; aliphatic tri(meth)acrylates; A (poly)oxyalkylene-modified tri(meth)acrylate in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, (poly)oxypropylene chain, or (poly)oxytetramethylene chain is introduced into the molecular structure of; Examples include lactone-modified tri(meth)acrylates in which a (poly)lactone structure is introduced into the molecular structure of aliphatic tri(meth)acrylates.

Specific examples of poly(meth)acrylates or modified products thereof include aliphatic poly(meth)acrylates such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. ) Acrylate; (poly)oxyalkylene chains such as (poly)oxyethylene chains, (poly)oxypropylene chains, and (poly)oxytetramethylene chains are introduced into the molecular structure of aliphatic poly(meth)acrylates. ) Oxyalkylene-modified poly(meth)acrylate; Examples include lactone-modified poly(meth)acrylate in which a (poly)lactone structure is introduced into the molecular structure of an aliphatic poly(meth)acrylate.

The curable resin composition of the present invention may contain an organic solvent for the purpose of adjusting its viscosity. The type and amount of organic solvent added are adjusted as appropriate depending on desired performance. Generally, the amount of organic solvent used is approximately 10 to 90% by mass of the total amount of the curable resin composition.
Specific examples of organic solvents include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cyclic ether solvents such as tetrahydrofuran and dioxolane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; Aromatic solvents such as toluene and xylene; Alicyclic solvents such as cyclohexane and methylcyclohexane; Alcohol solvents such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether; Alkylene glycol monoalkyl Examples include glycol ether solvents such as ether, dialkylene glycol monoalkyl ether, and dialkylene glycol monoalkyl ether acetate. In addition, these solvents may be used alone or in combination of two or more.

The curable resin composition of the present invention also contains various additives such as inorganic or organic fine particles, pigments, antifoaming agents, viscosity modifiers, leveling agents, flame retardants, and storage stabilizers. It's okay.
The curable imide resin of the present invention has excellent handling properties such as a long pot life, and also has excellent alkali developability such as sensitivity during development. The cured product (resin film) has particularly excellent flexibility in addition to heat resistance and mechanical strength. In addition, the curable imide resin of the present invention has excellent solvent solubility, adhesion of the cured product to a substrate, and non-adhesiveness after temporary drying.

The curable resin composition (curable imide resin) of the present invention can be suitably used, for example, as a material for the following applications.
That is, in the application of semiconductor devices, it can be used as a solder resist material, an interlayer insulation material, a package material, an underfill material, a package adhesive material for circuit elements, and an adhesive material between an integrated circuit element and a circuit board. In addition, in applications for thin displays such as LCDs and OELDs, it can be suitably used as a protective material for thin film transistors, a protective material for liquid crystal color filters, a coloring material for color filters, a black material for a black matrix, and a spacer material.
Among these, the curable resin composition of the present invention is more preferably used for a solder resist material. In this case, the curable resin composition of the present invention may contain components such as a curing agent, a curing accelerator, and an organic solvent in addition to the curable imide resin, a photopolymerization initiator, and various additives. .

The curing agent is not particularly limited as long as it is a compound having a functional group that can react with the carboxyl group of the curable imide resin of the present invention. Examples of such curing agents include epoxy resins.
Examples of the epoxy resin include bisphenol type epoxy resin, phenylene ether type epoxy resin, naphthylene ether type epoxy resin, biphenyl type epoxy resin, triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and bisphenol type epoxy resin. Novolac type epoxy resin, naphthol novolac type epoxy resin, naphthol-phenol cocondensed novolak type epoxy resin, naphthol-cresol cocondensation novolak type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene-phenol addition reaction Examples include molded epoxy resins. These epoxy resins may be used alone or in combination of two or more.
Among these, epoxy resins include phenol novolak epoxy resins, cresol novolac epoxy resins, bisphenol novolac epoxy resins, and naphthol novolac epoxy resins, since they can further improve the heat resistance of the resin film (cured product of the curable resin composition). Preferred are novolac type epoxy resins such as naphthol-phenol cocondensed novolac type epoxy resins, naphthol-cresol cocondensed novolac type epoxy resins.
Further, the softening point of the epoxy resin is preferably about 50 to 120°C. By using an epoxy resin having such a softening point, the physical properties of the curable resin composition become better.

The curing accelerator is a component used for the purpose of accelerating the curing reaction caused by the curing agent.
When an epoxy resin is used as a curing agent, suitable curing accelerators include, for example, phosphorus compounds, tertiary amines, imidazole, organic acid metal salts, Lewis acids, and amine complex salts. In addition, these compounds may be used individually by 1 type, or may use 2 or more types together.
The amount of the curing accelerator added is preferably about 1 to 10 parts by weight per 100 parts by weight of the curing agent.
The organic solvent is not particularly limited as long as it can dissolve various components such as the curable imide resin and the curing agent.
Examples of such organic solvents include methyl ethyl ketone, acetone, dimethyl formamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and the like.

The cured product of the present invention is obtained by curing the curable resin composition. Moreover, the method for producing a cured product of the present invention includes a step of curing the curable resin composition.
In addition, as a method for forming a resin film (cured coating film) using the curable resin composition of the present invention, for example, a coating film (liquid coating film) is formed by applying the curable resin composition onto a substrate. After forming and removing the organic solvent from the coating film at a temperature of about 60 to 100°C, it is exposed to active energy rays (ultraviolet rays, electron beams, etc.) through a photomask having a desired pattern shape, Examples include a method of developing the unexposed area with an alkaline solution and curing it by heating at a temperature of about 140 to 180°C.
The curable imide resin, curable resin composition, method for producing a curable imide resin, method for producing a curable resin composition, cured product, and method for producing a cured product of the present invention have been described above. However, the present invention is not limited to the configuration of the embodiment described above.
The curable imide resin, curable resin composition, and cured product of the present invention may additionally have any other configuration in addition to the configuration of the above-described embodiment, or any other configuration that exhibits the same function. may be replaced with the configuration of
Further, the method for producing a curable imide resin, the method for producing a curable resin composition, and the method for producing a cured product of the present invention may include any other optional steps in addition to the above-described embodiments. or may be replaced with any process that performs the same function.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.
1. Preparation of curable imide resin solution [Curable imide resin solution (A)]
First, in a flask equipped with a stirrer, a thermometer, and a condenser, 195.3 g of diethylene glycol monoethyl ether acetate (EDGA), 31.1 g (0.14 mol) of isophorone diisocyanate (IPDI), and 261.8 g (0.0 .07 mol) of OH group-terminated polybutadiene ("G-3000" manufactured by Nippon Soda Co., Ltd., hydroxyl value = 30 mgKOH/g) was supplied, and after heating this mixed solution to 60 ° C., it was maintained at this temperature for 2 hours. did.
Next, 30.1 g of EDGA and 45.08 g (0.14 mol) of bensophenone tetracarboxylic dianhydride (BTDA) were added to the mixed solution (reaction solution). Thereafter, the temperature of the mixed solution was raised to 140° C. over 2 hours, and then the reaction was continued for 10 hours.
The reaction proceeded with foaming. As a result of measuring the characteristic absorption in an infrared spectrum, the absorption peak at 2270 cm ^-1 , which is the characteristic absorption of the isocyanate group, completely disappeared, and absorption peaks attributable to imide bonds were confirmed at 1770 cm ^-1 and 1720 cm ^-1 . .
Further, the acid value of the sample was 25.2 mgKOH/g. Note that the acid value was measured after dissolving the sample in a THF/water ratio of 9/1 (volume ratio) (the same applies hereinafter).
Next, after cooling the mixed solution to 100 ° C., 42.1 g of EDGA and 69.6 g of pentaerythritol triacrylate (“Aronix M-305” manufactured by Toagosei Co., Ltd., hydroxyl value = 118.5 mg KOH / g) , 0.056 g of methoquinone were added, and the reaction was continued for 3 hours. As described above, a curable imide resin having an acryloyl group was synthesized. The 69.6 g of pentaerythritol triacrylate added above contains 0.15 mol of hydroxyl groups.
The number average molecular weight of the curable imide resin was 600, and the acid value (in terms of solid content) was 24.3 mgKOH/g. Moreover, the nonvolatile content concentration of the mixed solution (resin solution) was 58.1%, and the viscosity (at 25° C.) was 60.7 Pa·s. This mixed solution was designated as a curable imide resin solution (A).

[Curable imide resin solution (B)]
First, in a flask equipped with a stirrer, thermometer, and condenser, 197.6 g of EDGA, 50.0 g (0.23 mol) of IPDI, and 147.6 g (0.15 mol) of OH group-terminated polycarbonate (Co., Ltd. "C-1090" manufactured by Kuraray, hydroxyl value=114 mgKOH/g) was supplied, and the mixed solution was heated to 60° C. and then held at this temperature for 2 hours.
Next, 35.1 g of EDGA and 48.3 g (0.15 mol) of BTDA were added to the mixed solution (reaction solution). Thereafter, the temperature of the mixed solution was raised to 160° C. over 2 hours, and then the reaction was continued for 10 hours.
The reaction proceeded with foaming. As a result of measuring the characteristic absorption in an infrared spectrum, the absorption peak at 2270 cm ^-1 , which is the characteristic absorption of the isocyanate group, completely disappeared, and absorption peaks attributable to imide bonds were confirmed at 1770 cm ^-1 and 1720 cm ^-1 . .
Further, the acid value of the sample was 36.2 mgKOH/g.
Next, after cooling the mixed solution to 100 ° C., 74.6 g of EDGA and 74.6 g of pentaerythritol triacrylate (“Aronix M-305” manufactured by Toagosei Co., Ltd., hydroxyl value = 118.5 mg KOH/g) were added. , 0.047 g of methoquinone were added, and the reaction was continued for 3 hours. As described above, a curable imide resin having an acryloyl group was synthesized. The 74.6 g of pentaerythritol triacrylate added above contains 0.16 mol of hydroxyl groups.
The number average molecular weight of the curable imide resin was 1,000, and the acid value (in terms of solid content) was 20.1 mgKOH/g. Moreover, the nonvolatile content concentration of the mixed solution (resin solution) was 50.1%, and the viscosity (at 25° C.) was 600 mPa·s. This mixed solution was designated as a curable imide resin solution (B).

[Curable imide resin solution (C)]
The mixed solution (resin solution) before adding pentaerythritol triacrylate was used as a curable imide resin solution (C). Therefore, the curable imide resin in this example does not have an acryloyl group.
The number average molecular weight of the curable imide resin was 707, and the acid value (in terms of solid content) was 26.8 mgKOH/g. Moreover, the nonvolatile content concentration of the mixed solution (resin solution) was 59.8%, and the viscosity (at 25° C.) was 37.8 Pa·s.

[Curable imide resin solution (D)]
First, isocyanurate-type triisocyanate (IPDI3N, NCO%=17. 2) and 80.6 g (0.42 mol) of trimellitic anhydride were supplied, and the mixed solution was heated to 160° C. while stirring. At this time, vigorous foaming began around 60° C., and the mixed solution gradually became transparent. The reaction was carried out at 160°C for 4 hours, and when the isocyanate group content in the system reached 1.8%, it was cooled to 80°C.
Next, 0.27 g of methylhydroquinone was added to the mixed solution (reaction solution), and then 49.7 g (number of moles of hydroxyl group = 0.105 mol) of pentaerythritol triacrylate was added, taking care not to generate heat. The reaction was carried out at 80°C for 4 hours. Thereafter, the characteristic absorption was measured using an infrared spectrum, and it was confirmed that the absorption peak at 2270 cm ^-1 , which is the characteristic absorption of the isocyanate group, had disappeared. As described above, a branched curable imide resin having an acryloyl group was synthesized.
The number average molecular weight of the curable imide resin was 1,201, and the acid value (in terms of solid content) was 50.1 mgKOH/g. Moreover, the nonvolatile content concentration of the mixed solution was 40.2%, and the viscosity (25° C.) was 1.0 Pa·s. This mixed solution was designated as a curable imide resin solution (D).

2. Preparation of curable resin composition (Example 1)
First, 30 parts by mass of a curable imide resin solution (A), 3.0 parts by mass of a cresol novolak type epoxy resin solution, and 0.87 parts by mass of 4'-(methylthio)-α-morpholino-α-methyl Mix propiophenone ("IRGACURE907" manufactured by BASF), 0.17 parts by mass of triphenylphosphine (TPP), and 0.09 parts by mass of phthalocyanine pigment ("FASTOGEN BLUE" manufactured by DIC Corporation). A curable resin composition was prepared. The cresol novolac type epoxy resin solution was a mixture of "EPICLON N-680" manufactured by DIC Corporation (non-volatile content = 100%, epoxy equivalent = 214) and EDGA at a mass ratio of 65:35. A solution prepared as follows was used.
(Example 2, Comparative Example 1 and Comparative Example 2)
A curable resin composition was prepared in the same manner as in Example 1, except that the types and mixing amounts of each component were changed as shown in Table 1.

3. Evaluation 3-1. Ultraviolet curability The obtained curable resin composition was applied onto a copper base material using an applicator to form a coating film with a dry film thickness of 30 μm.
Next, this coating film was pre-dried at 80° C. for 30 minutes, then irradiated with ultraviolet rays and evaluated according to the following criteria. Note that a metal halide lamp was used as the ultraviolet light source, and the cumulative amount of ultraviolet ray irradiation was 1,000 mJ/cm ² .
○: UV curable ×: UV curable 3-2. Thermosetting The obtained curable resin composition was applied onto a copper base material using an applicator to form a coating film with a dry film thickness of 30 μm.
Next, this coating film was pre-dried at 80° C. for 30 minutes, then thermally cured at 160° C. for 60 minutes, and evaluated according to the following criteria.
○: Thermosetting ×: No thermosetting

3-3. Coating film physical property test The obtained curable resin composition was applied onto a copper substrate using an applicator to form a coating film with a dry film thickness of 30 μm.
Next, this coating film was preliminarily dried at 80° C. for 30 minutes, and then cured by ultraviolet ray irradiation and thermally cured at 160° C. for 60 minutes to obtain a cured coating film. Thereafter, the cured coating was peeled off from the copper substrate.
Using this peeled cured coating film, the following coating film physical properties were measured.
<Glass transition temperature (Tg)>
Dynamic viscoelasticity was measured under the following conditions, and the temperature at which Tan δ of the obtained chart showed the maximum value was defined as "Tg".
Measuring equipment: Rheoviblon RSA-III (manufactured by Rheometric Co., Ltd.)
Jig: Tension Chuck distance: 20mm
Measurement temperature range: 25-400℃
Measurement frequency: 1Hz
Temperature increase rate: 3℃/min

<Tensile test>
A tensile test was conducted under the following conditions, and the elongation, breaking strength, and elastic modulus were determined from the obtained chart.
Measuring equipment: Precision universal testing machine Autograph AG-IS (1kN) (Shima Co., Ltd.)
(manufactured by Tsu Seisakusho)
Measurement environment: room temperature 23℃, humidity 50%
Tensile test speed: 10mm/min
The above results are shown in Table 1 below.

As shown in Table 1, the curable imide resins of Examples 1 and 2 had a (meth)acryloyl group and a carboxyl group, and thus exhibited ultraviolet curability and thermosetting properties. On the other hand, the curable imide resin of Comparative Example 1 has a carboxyl group (carboxylic acid anhydride group) but no (meth)acryloyl group, so it exhibits thermosetting properties but has no UV curability. Didn't show it. Furthermore, the cured coating film formed on the copper base material did not have sufficient strength, so it was impossible to peel it off from the copper base material when measuring physical properties.
Moreover, since the curable imide resins of Examples 1 and 2 each had a soft segment derived from polybutadiene or polycarbonate, the resulting cured coating films exhibited excellent flexibility. On the other hand, since the curable imide resin of Comparative Example 2 did not have a soft segment, the obtained cured coating film had poor flexibility.

Claims (17)

A curable imide resin that can be cured by irradiation with active energy rays,
The curable imide resin has an imide resin (a) having a divalent chain group and two or more carboxylic anhydride groups, a reactive group that can react with the carboxylic anhydride group, and ethylenically unsaturated. It is obtained by reacting with a reactive compound (b) having a group,
The imide resin (a) contains as a raw material a hydroxyl group-containing compound (a1) having the chain group and two or more hydroxyl groups and having a number average molecular weight of 200 to 5,000,
The hydroxyl group-containing compound (a1) is a polyolefin polyol and/or a polycarbonate polyol,
A curable imide resin, wherein the reactive compound (b) contains pentaerythritol tri(meth)acrylate. The imide resin (a) further contains, as raw materials, an isocyanate compound (a2) having two or more isocyanate groups, and an acid anhydride group-containing compound (a3) having two or more of the carboxylic acid anhydride groups. The curable imide resin according to claim 1, which contains the following. The isocyanate compound (a2) is at least one selected from the group consisting of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and isophorone diisocyanate. The curable imide resin according to claim 2, which is one type. The curable imide resin according to claim 2 or 3, wherein the acid anhydride group-containing compound (a3) is a tetracarboxylic dianhydride. The tetracarboxylic dianhydride includes pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic anhydride, P-phenylene bis( trimellitate anhydride), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, cyclobutanetetracarboxylic anhydride, cyclopentanetetracarboxylic anhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic anhydride Acid dianhydride and 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione The curable imide resin according to claim 4, which is at least one selected from the group consisting of: The curable imide resin according to any one of claims 1 to 5, wherein the reactive group of the reactive compound (b) is a hydroxyl group. The curable imide resin according to any one of claims 1 to 6, wherein the curable imide resin has an acid value of 10 to 150 mgKOH/g in terms of solid content. The curable imide resin according to any one of claims 1 to 7, wherein the curable imide resin has a number average molecular weight of 400 to 20,000. A curable imide resin according to any one of claims 1 to 8,
A curable resin composition comprising a photopolymerization initiator. The curable resin composition according to claim 9, further comprising a curing agent. The curable resin composition according to claim 10, wherein the curing agent is an epoxy resin. The curable resin composition according to claim 11, wherein the epoxy resin is a novolac type epoxy resin. The curable resin composition according to claim 11 or 12, wherein the epoxy resin has a softening point of 50 to 120°C. A method for producing a curable imide resin that can be cured by irradiation with active energy rays, the method comprising:
An imide resin (a) having a divalent chain group and two or more carboxylic anhydride groups, and a reactive compound having an ethylenically unsaturated group and a reactive group capable of reacting with the carboxylic anhydride group ( b) having a step of reacting with
The imide resin (a) contains as a raw material a hydroxyl group-containing compound (a1) having the chain group and two or more hydroxyl groups and having a number average molecular weight of 200 to 5,000,
The hydroxyl group-containing compound (a1) is a polyolefin polyol and/or a polycarbonate polyol,
A method for producing a curable imide resin, wherein the reactive compound (b) contains pentaerythritol tri(meth)acrylate. A method for producing a curable resin composition, comprising the step of blending the curable imide resin according to any one of claims 1 to 8 and a photopolymerization initiator. A cured product obtained by curing the curable resin composition according to any one of claims 9 to 13. A method for producing a cured product, comprising the step of curing the curable resin composition according to any one of claims 9 to 13.