JP2011157502A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition producible of a low resilient cured product, which has excellent heat resistance and hardly causes a warp, a circuit board protective film-forming material using the resin composition, and a circuit board. <P>SOLUTION: The resin composition has a glass transition temperature of 50-120°C after heat curing and an elastic modulus of 0.3-1.4 GPa, causes no swelling or burnt deposit when immersed in a molten solder bath at 260°C for 60 seconds, and has flame retardancy of VTM-1 or more in the UL-94 standard. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a heat-resistant resin composition useful as a surface protective film, an interlayer insulating film, a bonding sheet, and a printed wiring board protective insulating film of a semiconductor element, and an electronic component such as a circuit board using the resin composition. Is.

  As a surface protective film for semiconductor elements, an interlayer insulating film, and a protective insulating film for printed wiring boards, polyimide is increasingly used because of its excellent heat resistance. In particular, when applied to a flexible wiring circuit, there is a demand for less warping after curing. As a resin composition having excellent heat resistance and preventing warping after curing, a polyimide ink composed of an ester terminal oligomer and an amine terminal oligomer has been disclosed (for example, see Patent Document 1). However, such a resin composition needs to be heat-treated at least at 250 ° C. or higher for imidization, and the formed polyimide resin has a large shrinkage and has a problem in workability. In addition, when copper foil is used as the circuit material, there is a problem that a reaction between the carboxyl group and the wiring material occurs and the wiring material is oxidized.

  On the other hand, there is disclosed a polyimidesiloxane precursor that can be cured at a low temperature and that uses diaminosiloxane as a diamine component in order to suppress warping after curing (see, for example, Patent Document 2 and Patent Document 3). ). However, when these polyimidesiloxane precursors are applied to a circuit board and imidized to form a protective film for the circuit, the adhesive force between the protective film and the adhesive sheet is insufficient in the subsequent prepreg or bonding process. There is a problem.

  Further, a non-silicone polyimide precursor in which a part of polyamic acid is partially imidized by using alkyl ether diamine to lower imidation temperature for photosensitive dry film resist is disclosed (for example, see Patent Document 4). ). However, the cured product composed of these partially imidized polyimide precursors has insufficient flexibility.

Japanese Patent Laid-Open No. 2-145664 JP-A-57-143328 JP 58-13631 A JP 2006-321924 A

  This invention is made in view of this point, and it aims at providing the resin composition which is excellent in heat resistance, has few curvature, and can obtain the hardened | cured material of low resilience. It is another object of the present invention to provide a protective film forming material for a circuit board and a circuit board using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the glass transition temperature after thermosetting is 50 ° C. to 120 ° C., the elastic modulus is 0.3 GPa to 1.4 GPa, and the solder bath It was found that a resin composition having flame retardancy equal to or higher than VTM-1 in the UL-94 standard can solve the problem when it is immersed at 260 ° C. for 60 seconds. The present invention has been made based on this finding. Furthermore, the present inventors have found that the composition of the resin composition preferably includes a specific polyimide precursor having a controlled imidization rate and a compound having a thermally crosslinkable functional group. That is, the present invention is as follows.

  The resin composition of the present invention has a glass transition temperature after thermosetting of 50 ° C. to 120 ° C. and an elastic modulus of 0.3 GPa to 1.4 GPa, and swells when immersed in a solder bath at 260 ° C. for 60 seconds. -Satisfying non-burning and has flame retardancy of VTM-1 or higher according to UL-94 standards.

  In the resin composition of the present invention, the change in the weight average molecular weight Mw is preferably 10% or less after the resin composition has been stored for 1 month.

  In the resin composition of this invention, it is a resin composition containing a polyimide precursor and the compound which has a heat crosslinkable functional group, Comprising: The said polyimide precursor is at least represented by following General formula (1). It is preferable to have a polyimide precursor comprising a diamine component having one kind of alkyl ether group as an essential component.

（式（１）中、Ｒ１、Ｒ２、Ｒ３、Ｒ４、及びＲ５は炭素数１〜炭素数５のアルキレン基を表し、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４及びＲ１５は水素原子または炭素数１〜炭素数５のアルキル基を表し、ｍ、ｎ、及びｑは１〜２０の整数を表す。）

(In the formula (1), R1, R2, R3, R4 and R5 represent an alkylene group having 1 to 5 carbon atoms, and R6, R7, R8, R9, R10, R11, R12, R13, R14 and R15. Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m, n, and q represent an integer of 1 to 20.)

  In the resin composition of the present invention, the compound having a thermally crosslinkable functional group is preferably at least one compound selected from the group consisting of a triazine compound, a benzoxazine compound, and a blocked isocyanate compound.

  In the resin composition of this invention, it is preferable that content of the diamine represented by the said General formula (1) with respect to all the diamines is 25 mol%-60 mol%.

  In the resin composition of this invention, it is preferable to contain the compound which has the said heat crosslinkable functional group in 5-40 mass parts with respect to 100 mass parts of said polyimide precursors.

  The resin composition of the present invention preferably contains a flame retardant.

  A material for forming a protective film of a printed circuit board according to the present invention is characterized by comprising the above resin composition.

  The cured product of the present invention is obtained by thermosetting the resin composition.

  The circuit board of the present invention includes a base material having wiring and the cured product that covers the surface of the base material.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition which is excellent in heat resistance, has few curvature, and can obtain the hardened | cured material of low resilience can be provided. Moreover, a protective film forming material for a circuit board and a circuit board using the same can be provided.

Hereinafter, the present invention will be specifically described.
The resin composition according to the present invention has a glass transition temperature after thermosetting of 50 ° C. to 120 ° C. and an elastic modulus of 0.3 GPa to 1.4 GPa, and when immersed in a solder bath at 260 ° C. for 60 seconds, It is a resin composition that satisfies the absence of blistering and scoring and has flame retardancy of VTM-1 or higher according to the UL-94 standard, has excellent heat resistance after curing, and exhibits low warpage, low resilience, and flame retardancy. The composition of the resin composition is a resin composition containing a polyimide precursor and a compound having a thermally crosslinkable functional group, and the polyimide precursor is at least one kind represented by the following general formula (1). What has the polyimide precursor which contains the diamine component which has an alkyl ether group as an essential component is preferable.

（式（１）中、Ｒ１、Ｒ２、Ｒ３、Ｒ４、及びＲ５は炭素数１〜炭素数５のアルキレン基を表し、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４及びＲ１５は水素原子または炭素数１〜炭素数５のアルキル基を表し、ｍ、ｎ、及びｑは１〜２０の整数を表す。）

(In the formula (1), R1, R2, R3, R4 and R5 represent an alkylene group having 1 to 5 carbon atoms, and R6, R7, R8, R9, R10, R11, R12, R13, R14 and R15. Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m, n, and q represent an integer of 1 to 20.)

  By including a diamine component having an alkyl ether group as an essential component in the polyimide precursor, the glass transition temperature and elastic modulus of the cured product after thermosetting can be controlled, and there is little warpage and low resilience can be expressed. . And the resin composition which concerns on this invention forms the bridge | crosslinking of the compound which has a heat crosslinkable functional group after thermosetting. Since chemical cross-linking between a polyimide having a specific structure and a compound having a heat-crosslinkable functional group, and a polyimide having a specific structure has a polyoxyalkylene chain, local interaction between polymer chains By forming a three-dimensional network, the heat resistance can be expressed.

  Especially, it is preferable that the glass transition temperature after hardening is 61 degreeC-98 degreeC, and the elasticity modulus after hardening is 0.4 GPa-1.0 GPa, and it is still lower by setting it as the resin composition which satisfy | fills this characteristic. Shows warpage and low resilience, and also satisfies heat resistance.

  Furthermore, if the change in the weight average molecular weight Mw is 10% or less after storage for 1 month, the pot life of the resin composition is long and excellent in storage stability, which is preferable in handling.

  Further, as the polyimide precursor, it is preferable to use partially imidized polyimide. The partial imidation is the imidation of a part of the polyamic acid in the molecular chain of the polyimide precursor. The imidation ratio of the polyimide precursor is more preferably in the range of 40% to 100%, and still more preferably in the range of 70% to 100%. If the imidation ratio of the polyimide precursor is 40% or more, the residue of the carboxyl group in the polyimide precursor is reduced to some extent, so that the storage stability is excellent.

(A) Polyimide precursor The polyimide precursor which contains the diamine component which has at least 1 type of alkyl ether group represented by following General formula (1) as an essential component is demonstrated.

（式（１）中、Ｒ１、Ｒ２、Ｒ３、Ｒ４、及びＲ５は炭素数１〜炭素数５のアルキレン基を表し、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４及びＲ１５は水素原子または炭素数１〜炭素数５のアルキル基を表し、ｍ、ｎ、及びｑは１〜２０の整数を表す。）

(In the formula (1), R1, R2, R3, R4 and R5 represent an alkylene group having 1 to 5 carbon atoms, and R6, R7, R8, R9, R10, R11, R12, R13, R14 and R15. Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m, n, and q represent an integer of 1 to 20.)

  Examples of the diamine represented by the general formula (1) include polyoxyethylene diamine, polyoxypropylene diamine, and other polyoxyalkylene diamines containing oxyalkylene groups having different carbon chain numbers. Examples of polyoxyalkylene diamines include polyoxyethylene diamines such as Jeffamine ED-600, ED-900, ED-2003, EDR-148, and HK-511 manufactured by Huntsman, Inc., and Jeffamine D-230 and D-400. Examples thereof include polyoxypropylenediamines such as D-2000 and D-4000, and polytetramethyleneethylene groups such as Jeffamine XTJ-542, XTJ-533, and XTJ-536.

  Among them, EDR-148, D-230, D-400, HK-511 and the like having a relatively low molecular weight can be a polymer having a relatively high glass transition temperature, and thus are preferable for applications requiring heat resistance and chemical resistance. Used. On the other hand, D-2000 or the like having a relatively high molecular weight is excellent in flexibility and the like. Moreover, as a weight average molecular weight of polyoxyalkylene diamine, 400-1400 are preferable and 500-1000 are especially preferable from the point of heat resistance, chemical-resistance, a softness | flexibility, and solvent solubility. As the polyoxydiamine having such weight average molecular weight, ED-600, ED-900, and XTJ-542 are preferably used. Among these, ED-600 and ED-900, which are polyoxyethylene diamines having an ethylene group, are particularly preferably used because of their improved solvent solubility.

  It is preferable that content of the diamine represented by the said General formula (1) is 25 mol%-80 mol% with respect to all the diamines. More preferably, it is 25 mol%-60 mol%, More preferably, it is 30 mol%-50 mol%. If it is 25 mol% or more, low warpage and low resilience are exhibited, and if it is 80 mol% or less, the solvent resistance and heat resistance are excellent. In addition, the diamine represented by the general formula (1) does not contain an ester group in its molecular structure and has a polyoxyalkylene group having an appropriate length. As described above, since the hydrolyzable ester group is not contained in the molecular chain, the cured product has good stability after curing, particularly under high temperature and high humidity. Moreover, since the molecular chain has an appropriate length and an appropriate polarity, warpage and resilience can be reduced.

  In addition, the diamine represented by the general formula (1) is likely to have a high molecular weight as the polyamic acid when a diamine having a high purity is used. The purity of the diamine represented by the general formula (1) is preferably 95% or more, more preferably 97% or more, and further preferably 98.5% or more.

  Examples of diamines that can be used other than the diamine represented by the general formula (1) include 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenyl ether, and 4,4′-. Diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, bis (3- (3-aminophenoxy) phenyl) ether, bis (4- (4- Aminophenoxy) phenyl) ether, 1,3-bis (3- (3-aminophenoxy) phenoxy) benzene, 1,4-bis (4- (4-aminophenoxy) phenoxy) benzene, bis (3- (3- (3-Aminophenoxy) phenoxy) phenyl) ether, bis (4- (4- (4-aminophenoxy) pheno Cis) phenyl) ether, 1,3-bis (3- (3- (3-aminophenoxy) phenoxy) phenoxy) benzene, 1,4-bis (4- (4- (4-aminophenoxy) phenoxy) phenoxy) Benzene, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2, 2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2 , 2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, -Phenylenediamine, bis (3-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, α, ω-bis (2-aminoethyl) polydimethylsiloxane, α, ω-bis (3-amino Propyl) polydimethylsiloxane, α, ω-bis (4-aminobutyl) polydimethylsiloxane, α, ω-bis (4-aminophenyl) polydimethylsiloxane, α, ω-bis (3-aminopropyl) polydiphenylsiloxane However, it is not limited to these. Preferred are 4,4'-bis (3-aminophenoxy) biphenyl, 1,3-bis (3- (3-aminophenoxy) phenoxy) benzene, and 1,3-bis (3-aminophenoxy) benzene.

  It is preferable that 20 mol%-75 mol% of diamines which can be used other than the diamine represented by the said General formula (1) are included with respect to all the diamines. More preferably, it is 40 mol%-75 mol%, More preferably, it is 50 mol%-70 mol%. By using 20 mol% or more with respect to all diamines, the solvent resistance is excellent, and by using 75 mol% or less, warpage and resilience are suppressed.

  There is no restriction | limiting in tetracarboxylic dianhydride, A conventionally well-known tetracarboxylic dianhydride can be used. Specific examples of the tetracarboxylic dianhydride include, as aromatic tetracarboxylic acids, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′. , 4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2, 2 ', 3,3'-benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane Dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxy) Phenyl) Dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 3,3′-oxydiphthalic dianhydride, 4,4 ′ Oxydiphthalic dianhydride, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 1,3-dihydro-1,3-dioxo-5-isobenzofurancarboxylic acid-1,4-phenylene ester 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 1,2,5,6-naphthalenetetracarboxylic acid Anhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic Dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) phenyl) hexafluoropropane dianhydride 2,2-bis (4- (3,4-dicarboxybenzoyloxy) phenyl) hexafluoropropane dianhydride, 2,2′-bis (trifluoromethyl) -4,4′-bis (3,4 -Dicarboxyphenoxy) biphenyl dianhydride and the like.

  Specific examples of the tetracarboxylic dianhydride include an aliphatic tetracarboxylic dianhydride such as cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3 , 5,6-cyclohexanetetracarboxylic dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2 , 2,2] oct-7-ene-2,3,5,6 tetracarboxylic dianhydride and 1,2,3,4-butanetetracarboxylic dianhydride. These tetracarboxylic dianhydrides may be used alone or in admixture of two or more.

  Among these tetracarboxylic dianhydrides, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-oxydiphthalic dianhydride are used from the viewpoint of heat resistance and polymerization rate of polyimide. And 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride are preferred.

  A method for producing polyimide will be described. As a method for producing polyimide according to the present invention, all methods capable of producing polyimide, including known methods, can be applied. Among these, it is preferable to perform the reaction in an organic solvent. As a solvent used in such a reaction, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 1,3 -Dioxane, 1,4-dioxane, dimethyl sulfoxide, benzene, toluene, xylene, mesitylene, phenol, cresol, ethyl benzoate, butyl benzoate and the like. These may be used alone or in combination of two or more.

  The density | concentration of the reaction raw material in this reaction is 2 mass%-60 mass% normally, Preferably it is 30 mass%-50 mass%.

  The molar ratio of the acid dianhydride to be reacted and the diamine is in the range of 0.8 to 1.2. Within this range, the molecular weight can be increased, and the elongation and the like are excellent. Preferably it is 0.9-1.1, More preferably, it is 0.95-1.05.

  The weight average molecular weight of the polyimide is preferably 5000 or more and 100,000 or less. Here, the weight average molecular weight refers to a molecular weight measured by gel permeation chromatography using polystyrene having a known number average molecular weight as a standard. The weight average molecular weight is more preferably from 10,000 to 60,000, and most preferably from 20,000 to 50,000. When the weight average molecular weight is 5,000 or more and 100,000 or less, the warp of the protective film obtained using the resin composition is improved, and the low resilience and heat resistance are excellent. Furthermore, printing can be performed without blurring at a desired film thickness during coating printing, and mechanical properties such as elongation of the obtained protective film are excellent.

  Polyimide is obtained by the following method. First, a polyimide precursor is produced by polycondensation reaction of reaction raw materials at room temperature. Next, the polyimide precursor is preferably heated to 100 ° C. to 400 ° C. to imidize, or chemically imidized using an imidizing agent such as acetic anhydride, thereby repeating unit structure corresponding to polyamic acid. Is obtained. In the case of imidization by heating, in order to remove by-product water, dehydration is carried out under reflux using a Dean-Stark type dehydrator in the presence of an azeotropic agent (preferably toluene or xylene). Is also preferable.

  Moreover, it is also preferable to obtain a polyimide by carrying out the reaction at 80 ° C. to 220 ° C. to advance both the generation of the polyimide precursor and the thermal imidization reaction. That is, the diamine component and the acid dianhydride component are suspended or dissolved in an organic solvent and reacted under heating at 80 ° C. to 220 ° C. to cause both generation of a polyimide precursor and dehydration imidization. It is also preferable to obtain polyimide.

  Moreover, it is preferable that the terminal of the polymer main chain of polyimide is end-capped with an end-capping agent comprising a monoamine derivative or a carboxylic acid derivative. It is excellent in storage stability because the end of the polymer main chain of polyimide is sealed.

  Examples of the end capping agent comprising a monoamine derivative include aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,6-xylidine, 3,4-xylidine, and 3,5-xylidine. O-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline, m-bromoaniline, p-bromoaniline, o-nitroaniline, m-nitroaniline, p-nitroaniline, o-aminophenol M-aminophenol, p-aminophenol, o-anisidine, m-anisidine, p-anisidine, o-phenetidine, m-phenetidine, p-phenetidine, o-aminobenzaldehyde, m-aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzonitrile, m-aminobenzonitrile Ril, p-aminobenzonitrile, 2-aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, 2-aminophenylphenyl ether, 3-aminophenylphenyl ether, 4-aminophenylphenyl ether, 2-aminobenzophenone, 3 -Aminobenzophenone, 4-aminobenzophenone, 2-aminophenyl phenyl sulfide, 3-aminophenyl phenyl sulfide, 4-aminophenyl phenyl sulfide, 2-aminophenyl phenyl sulfone, 3-aminophenyl phenyl sulfone, 4-aminophenyl phenyl sulfone , Α-naphthylamine, β-naphthylamine, 1-amino-2-naphthol, 5-amino-1-naphthol, 2-amino-1-naphthol, 4-amino-1-naphthol, 5-amino Aromatic monoamines such as 2-naphthol, 7-amino-2-naphthol, 8-amino-1-naphthol, 8-amino-2-naphthol, 1-aminoanthracene, 2-aminoanthracene and 9-aminoanthracene Of these, derivatives of aniline are preferably used. These may be used alone or in combination of two or more.

  Examples of the terminal blocking agent comprising a carboxylic acid derivative include carboxylic anhydride derivatives, such as phthalic anhydride, 2,3-benzophenone dicarboxylic anhydride, 3,4-benzophenone dicarboxylic anhydride, 2,3- Dicarboxyphenyl phenyl ether anhydride, 3,4-dicarboxyphenyl phenyl ether anhydride, 2,3-biphenyl dicarboxylic acid anhydride, 3,4-biphenyl dicarboxylic acid anhydride, 2,3-dicarboxyphenyl phenyl sulfone anhydride 3,4-dicarboxyphenyl phenyl sulfone anhydride, 2,3-dicarboxyphenyl phenyl sulfide anhydride, 3,4-dicarboxyphenyl phenyl sulfide anhydride, 1,2-naphthalenedicarboxylic acid anhydride, 2, 3-Naphthalenedicarboxylic anhydride, 1,8-naphthalene Carboxylic acid anhydride, 1,2-anthracene dicarboxylic acid anhydride, 2,3-anthracene dicarboxylic acid anhydride, 1,9-aromatic dicarboxylic acid anhydrides such as anthracene dicarboxylic acid anhydride. Of these aromatic dicarboxylic acid anhydrides, phthalic anhydride is preferably used. These may be used alone or in combination of two or more.

  The obtained polyimide can be used as the resin composition according to the present invention as it is or without further solvent addition, without adding any solvent.

(B) Compound having a heat-crosslinkable functional group The compound having a heat-crosslinkable functional group is not particularly limited as long as it has a heat-crosslinkable functional group, and among them, a triazine compound, a benzoxazine compound, and a blocked isocyanate Preference is given to at least one compound selected from the group consisting of compounds.

  As the triazine compound, melamine and a compound represented by the following general formula (2) or the following general formula (3), melamines, and melamine cyanurate are preferable.

（式（２）中、Ｘ、Ｙ、Ｚはそれぞれ水素原子、酸素原子、硫黄原子または窒素原子を示す。Ｒ１６〜Ｒ２１は、それぞれ水素原子、炭素数１から炭素数５のアルキル基またはエーテル基であって、Ｘ、Ｙ、Ｚが水素原子の場合は、水素原子は置換基を有さないため、Ｒ１６〜Ｒ２１は存在しない。）

(In the formula (2), X, Y and Z each represent a hydrogen atom, an oxygen atom, a sulfur atom or a nitrogen atom. R16 to R21 each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an ether group. In the case where X, Y, and Z are hydrogen atoms, R16 to R21 are not present because the hydrogen atom has no substituent.

（式（３）中、Ｒ２２〜Ｒ２４、それぞれ水素原子、炭素数１から炭素数５のアルキル基またはエーテル基を示す。）

(In formula (3), R22 to R24 each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an ether group.)

  Specific examples of the compound represented by the general formula (2) include melamine, hexamethylol melamine, hexabutyrol melamine, triazine thiol diol, partially methylolated melamine and its alkylated product, tetramethylol benzoguanamine, and partial methylo. -Luminated benzoguanamine and alkylated products thereof. Specific examples of the compound represented by the general formula (3) include isocyanuric acid, trimethyl isocyanate, triethyl isocyanate, tris (2-hydroxyethyl) isocyanurate, tri (n-propyl) isocyanurate, diethyl isocyanurate, methyl isocyanate. Examples include nurate.

  Examples of melamines include melamine derivatives, compounds having a structure similar to melamine, and melamine condensates. Specific examples of melamines include methylolated melamine, ammelide, ammelin, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, melem, melon and the like.

  Examples of melamine cyanurates include equimolar reaction products of cyanuric acid and melamines. Moreover, some of the amino groups or hydroxyl groups in the melamine cyanurates may be substituted with other substituents. Among these, melamine cyanurate can be obtained, for example, by mixing an aqueous solution of cyanuric acid and an aqueous solution of melamine, reacting at 90 ° C. to 100 ° C. with stirring, and filtering the generated precipitate, Yes, a commercially available product can be used as it is or after being pulverized into a fine powder.

  These compounds having a thermally crosslinkable functional group can also be used as a mixture. Among these, a melamine / isocyanuric acid adduct is preferable in terms of good dispersibility. When used alone, triazine thiol diol and tris (2-hydroxyethyl) isocyanurate have good dispersibility.

  The benzoxazine compound is a compound having a benzoxazine ring represented by the following general formula (4).

（式（４）中、Ｒ２５は、炭素数１〜炭素数１２の鎖状アルキル基、炭素数３〜炭素数８の環状アルキル基、フェニル基、または炭素数１〜炭素数１２の鎖状アルキル基、若しくはハロゲンで置換されたフェニル基である。また、酸素原子が結合している芳香環中の炭素原子の、オルト位とパラ位の少なくとも一方の炭素原子には、水素が結合している。）

(In Formula (4), R25 is a chain alkyl group having 1 to 12 carbon atoms, a cyclic alkyl group having 3 to 8 carbon atoms, a phenyl group, or a chain alkyl having 1 to 12 carbon atoms. Or a phenyl group substituted with halogen, and hydrogen is bonded to at least one of the carbon atoms in the ortho-position and para-position of the aromatic ring to which the oxygen atom is bonded. .)

  Examples of the chain alkyl group having 1 to 12 carbon atoms in R25 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group. Examples of the cyclic alkyl group having 3 to 8 include a cyclopentyl group and a cyclohexyl group. The chain alkyl group having 1 to 12 carbon atoms or the phenyl group substituted with halogen includes o-methylphenyl group, m-methylphenyl group, p-methylphenyl group, o-ethylphenyl group, m- Examples thereof include an ethylphenyl group, a p-ethylphenyl group, an ot-butylphenyl group, an mt-butylphenyl group, a pt-butylphenyl group, an o-chlorophenyl group, and an o-bromophenyl group. . Among these, R11 is more preferably a methyl group, an ethyl group, a propyl group, a phenyl group, or an o-methylphenyl group in order to give good handleability.

  As the benzoxazine compound, for example, a compound represented by the following general formula (5) is preferably used.

（式（５）中、Ｒ２６は炭素数１から炭素数５の２価の有機基である。）

(In formula (5), R26 is a divalent organic group having 1 to 5 carbon atoms.)

Among them, R26 is preferably any one of divalent organic groups represented by the following formula group (6).

  The benzoxazine compound may be composed only of monomers, or several molecules may be polymerized into an oligomer state. Moreover, you may use the benzoxazine compound which has a different structure simultaneously. Specifically, bisphenol benzoxazine is preferably used.

  The blocked isocyanate is a compound obtained by reacting a blocking agent with an isocyanate having two or more isocyanate groups in the molecule. Examples of the isocyanate include 1,6-hexane diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate. Xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 4,4′-hydroxy diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 4,4- Diphenyl diisocyanate, 1,3-bis (isocyanate methyl) cyclohexane, phenylene 1,4-diisocyanate, phenylene 2,6-diisocyanate, 1,3,6-hexamethylene triisocyanate, Or hexamethylene diisocyanate etc. are mentioned. Blocking agents include alcohols, phenols, ε-caprolactam, oximes, active methylenes, mercaptans, amines, imides, acid amides, imidazoles, ureas, carbamates , Imines, sulfites, and the like are used.

  As a more specific product of the above-mentioned blocked isocyanate compound, for example, hexamethylene diisocyanate (hereinafter also referred to as “HDI”) block isocyanate, trade names Duranate 17B-60PX, TPA-B80E manufactured by Asahi Kasei Chemicals Corporation, TPA-B80X, MF-B60X, E402-B80T, ME20-B80S, MF-K60X, K6000 are used. Moreover, as Mitsui Chemicals Polyurethane products, trade name Takenate B-882N, trade name Takenate B-830 which is a tolylene diisocyanate block isocyanate, and 4,4'-diphenylmethane diisocyanate block isocyanate. Brand name Takenate B-815N, Takenate B-846N which is 1,3-bis (isocyanatemethyl) cyclohexane block isocyanate is used. Moreover, the brand name Coronate AP-M, 2503, 2515, 2507, 2513, or Millionate MS-50 by Nippon Polyurethane Industry Co., Ltd. is mentioned, These can be used individually or in combination of 2 or more types.

  In order to develop low-temperature curability at 200 ° C. or lower, it is preferable to use the above-mentioned HDI-based blocked isocyanate having a low curing temperature.

  The compound having a thermally crosslinkable functional group is contained in the range of 5 to 40 parts by mass with respect to 100 parts by mass of the polyimide precursor. If it is the range of 5 mass parts-40 mass parts, it is preferable, without impairing solder heat resistance, non-warping property, and flexibility. Especially, if it is 10 mass parts or more, it is especially preferable from the surface of a crosslinking density, and if it is 20 mass parts or less, it is especially preferable from the surface of curvature and resilience.

(C) Resin composition It is preferable that a resin composition contains the compound which has a heat crosslinkable functional group with respect to 100 mass parts of polyimides in the range of 1 mass part-40 mass parts. If it is the range of 1 mass part-40 mass parts, heat resistance (solder heat resistance), low curvature property, and flexibility will not be impaired, and it is preferable. Especially, if it is 5 mass parts or more, it is especially preferable from the surface of a crosslinking density, and if it is 20 mass parts or less, it is especially preferable from the surface of curvature and resilience.

  The resin composition may further contain an organic solvent in addition to (A) polyimide and (B) a compound having a thermally crosslinkable functional group. It can be preferably used as a varnish in a state dissolved in an organic solvent. Examples of such organic solvents include N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone and other amide solvents, γ- Lactone solvents such as butyrolactone and γ-valerolactone, sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide and hexamethyl sulfoxide, phenol solvents such as cresol and phenol, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), Examples include ether solvents such as tetraglyme, dioxane, tetrahydrofuran, butyl benzoate, ethyl benzoate, and methyl benzoate. These may be used alone or in combination. In particular, from the viewpoint of high boiling point and low water absorption, γ-butyrolactone, triglyme, butyl benzoate, and ethyl benzoate can be preferably used.

  The resin composition may further contain a flame retardant in addition to (A) polyimide and (B) a compound having a thermally crosslinkable functional group. The type of flame retardant is not particularly limited, and examples thereof include halogen-containing compounds, phosphorus-containing compounds, and inorganic flame retardants. One kind of these flame retardants may be used, or two or more kinds may be mixed and used.

  The addition amount of the flame retardant is not particularly limited, and may be appropriately changed according to the type of the flame retardant used. In general, it is preferably used in the range of 5 to 50 parts by mass with respect to 100 parts by mass of polyimide based on the polyimide content.

  Examples of the halogen-containing compound as the flame retardant include an organic compound containing chlorine and a compound containing bromine. Specific examples include pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane tetrabromobisphenol A, and the like.

  Examples of the phosphorus-containing compound as the flame retardant include phosphorus compounds such as phosphazene, phosphine, phosphine oxide, phosphate ester, and phosphite ester. In particular, from the viewpoint of compatibility with the polyimide composition, phosphazene, phosphite oxide, or phosphate ester is preferably used.

  Examples of the inorganic flame retardant include an antimony compound and a metal hydroxide. Antimony compounds include antimony trioxide and antimony pentoxide. In combination with the antimony compound and the above halogen-containing compound, antimony oxide pulls out halogen atoms from the flame retardant to produce antimony halide in the thermal decomposition temperature range of the plastic. . Examples of the metal hydroxide include aluminum hydroxide and magnesium hydroxide.

  When an inorganic flame retardant is used, it is not dissolved in an organic solvent, so the particle size of the powder is preferably 100 μm or less. If the particle size of the powder is 100 μm or less, it is preferable that the powder is easily mixed into the polyimide composition and does not impair the transparency of the cured resin. In order to further increase the flame retardancy, the particle size of the powder is preferably 50 μm or less, particularly preferably 10 μm or less.

  When forming a coating film, the viscosity and thixotropy are adjusted according to the coating method. If necessary, a filler or a thixotropic agent can be added and used. Moreover, it is also possible to add additives, such as a well-known antifoamer and a leveling agent.

  The film formation using the resin composition can be printed on the surface of a flexible printed circuit board or a semiconductor wafer by known screen printing or a precision dispensing method.

  In the resin composition, the imidization reaction of polyimide is sufficiently achieved at 150 to 220 ° C. Therefore, depending on the coating film thickness, the maximum temperature is in the range of 150 ° C to 220 ° C using an oven or hot plate, and the solvent is removed by heating in an inert atmosphere such as air or nitrogen for 5 minutes to 100 minutes. Is done. The temperature may be constant over the entire processing time, or may be performed while gradually raising the temperature.

  Since the resin composition exhibits excellent heat resistance when thermally cured, it is useful as a surface-cured film of semiconductor elements, an interlayer insulating film, a bonding sheet, or a protective insulating film for printed wiring boards, and can be used in various electronic components. Applied. Moreover, a resin composition can be used suitably as a surface protective film of the printed circuit board which has an electronic circuit. For example, Espanex M (manufactured by Nippon Steel Chemical Co., Ltd.) (insulating layer thickness: 25 μm, conductor layer: copper foil F2-WS (18 μm)) is used as a flexible printed circuit board, and resin is partially applied on the circuit board. Apply the composition. And it is used by giving electrolytic nickel-gold plating to the part which was not apply | coated. The surface protective film exhibits good insulating properties.

  In addition, a double-sided component-mounted circuit board was prepared using a double-sided copper-clad board of Espanex M (manufactured by Nippon Steel Chemical Co., Ltd.) (insulating layer thickness 25 μm, conductor layer copper foil F2-WS (18 μm)). Even if the resin composition is applied and cured in addition to the component mounting portion of the circuit board and the resin composition is used as a surface protective film, good insulating properties are exhibited. Here, the thickness of the surface protective film is preferably 1 μm to 50 μm. When the film thickness is 1 μm or more, handling is easy, and when the film thickness is 50 μm or less, it is easy to bend and easy to incorporate. A method for producing a polyimide precursor will be described. As a method for producing a polyimide precursor, all methods capable of producing a polyimide precursor, including known methods, can be applied.

  Hereinafter, the present invention will be described in detail with reference to examples and comparative examples carried out in order to clarify the curing of the present invention. In addition, this invention is not limited at all by the following examples and comparative examples.

(Production of cured film)
The cured film was produced as follows. Using Kapton (registered trademark) 100EN manufactured by Toray DuPont as a substrate, the resin composition was applied to the substrate with a bar coater on one side, and leveling was performed at room temperature for 5 to 10 minutes. Next, it was heated in a hot air oven at 120 ° C. for 30 minutes, and then heated at 180 ° C. for 60 minutes to dry and cure. The film thickness after drying and curing was about 20 μm. The produced cured film was used as a sample in the following tests.

(Measurement of imidization rate)
The imidization rate was determined by the IR method. 1480cm referenced to peak based on ^-1 vicinity of the benzene ring was determined imidization ratio from the ratio between the absorbance of the absorbance and the reference peak of a peak based on imide ring formation of 1380 cm ^-1 vicinity. In the measurement of the imidization rate, a base line is drawn appropriately so as to connect the valley of the peak before and after each peak, and the height from the intersection of the line drawn from each peak to the baseline and the peak to the peak is increased. The absorbance was taken as the respective absorbance. The imidization rate was calculated as follows using the absorbance measured as described above. The resin was synthesized at 50 ° C. for each composition, the absorbance of the absorbance A1,1380cm ^-1 at 1480 cm ^-1 of the resin when dried at 80 ° C. was B1. Also, 220 ° C., the absorbance of the absorbance A2,1380cm ^-1 at 60 minutes 1480 cm ^-1 of the resin at the time of heat treatment and B2, absorbance A3,1380cm ^-1 absorbance 1480 cm ^-1 at any temperature in an air atmosphere Is B3, the imidization ratio C at an arbitrary temperature is 220 ° C., and the imidization ratio during heat treatment for 60 minutes is 100, and the imidization ratio C = ((B3 / A3-B1 / A1) / (B2 / A2−B1 / A1)) × 100 (%).

(Warp evaluation)
The warpage evaluation was performed as follows. The sample was cut into 5 cm × 5 cm in an environment of 23 ° C. and humidity of 50%, and the distance at which the corner was raised relative to the central portion was measured as a warp. Those having a warp of 10 mm or less were good, those having a warpage of 5 mm or less were even better, and those having a warp of more than 10 mm were judged as x.

(Rebound evaluation)
The resilience is in an environment of 23 ° C and humidity of 50%. The side where the protective film is laminated is folded inward and sandwiched between parallel plates, and a load applied between the parallel plates is applied. The load when maintaining at R = 0.5 mm was measured and evaluated. Compared to the load of only Kapton (registered trademark) 100EN substrate, it is good when the load increase is 10% or less, ○ is better when it is 5% or less, and ◎ The repulsive force is increased beyond 10%. In case of failure, it was marked as x.

(Production of glass transition temperature (Tg) and elastic modulus measurement sample)
As the substrate, copper foil (18 μm) (F2-WS manufactured by Furukawa Circuit Foil Co., Ltd.) was used, and a protective film was formed on the substrate in the same manner as described above. The obtained laminate was immersed in a ferric chloride aqueous solution (40 Baume, manufactured by Tsurumi Soda Co., Ltd.) and etched to obtain only a protective film layer. After the etching, the glass transition temperature and the elastic modulus were measured after being left standing for a whole day and night at a temperature of 23 ° C. and a humidity of 50%.

(Glass transition temperature measurement)
The glass transition temperature (Tg) is measured in a nitrogen atmosphere (flow rate 250 cc / min) using a heat / stress / strain measuring apparatus (TMA / SS6100, manufactured by Seiko Instruments Nanotechnology Co., Ltd.), and a measurement range of 30 ° C. to 200 ° C. It measured on condition of this.

(Elastic modulus measurement)
A sample of only the above protective layer was cut out to 5 mm × 100 mm to obtain a test piece. The obtained test piece was measured with a tensile testing machine (RTG-1210 / manufactured by A & D) to obtain the elastic modulus.

(Storage stability)
As an evaluation of storage stability, changes in weight average molecular weight (Mw) and changes in viscosity were measured. After blending the resin composition, after storage for 1 month in a freezer at −20 ° C., when the weight average molecular weight (Mw) change is 10% or less, it is good. When the change was 10% or less, it was good, and when it exceeded 10%, it was judged as poor and x.

(Weight average molecular weight measurement)
The weight average molecular weight was measured under the following conditions using gel permeation chromatography (GPC). Using N, N-dimethylformamide (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) as a solvent, 24.8 mmol / L of lithium bromide monohydrate (manufactured by Wako Pure Chemical Industries, Ltd., purity before measurement) 99.5%) and 63.2 mmol / L phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) were used. A calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).
Column: TSK-GEL SUPER HM-H (manufactured by Tosoh Corporation)
Flow rate: 1.0 mL / min Column temperature: 40 ° C
Pump: PU-2080 Plus (manufactured by JASCO)
Detector: RI-2031Plus (RI: differential refractometer, manufactured by JASCO)
UV-2075 Plus (UV-VIS: UV-Visible Absorber, manufactured by JASCO)

(Viscosity measurement)
The viscosity was measured using a B-type viscometer (RE-85R, manufactured by Toki Sangyo Co., Ltd.) The viscosity was measured under measurement conditions of a measurement temperature of 23 ° C. and a rotation speed of 2.5 rpm.

(Heat resistance evaluation)
The heat resistance was evaluated by conducting a test in which a sample cut to 3 cm × 3 cm was immersed in a solder bath at 260 ° C. for 60 seconds. According to the JPCA-BM02 standard, it was observed with a 50 × stereomicroscope, and when there was no abnormality such as swelling or scorching on the film surface, it was rated as “good”, and when there was, it was marked as “poor”. The swelling here refers to a bulge of 5 μm or more on the surface of the cured film after the above solder bath float.

(Flame retardance evaluation)
The sample coated on both sides is cut into 200 mm x 50 mm, wound into a cylindrical shape with a length of 200 mm and a diameter of 12.7 mm, and is used as a flame retardancy evaluation scale in accordance with UL-94 of the US UL standard. The evaluation was performed according to the vertical combustion test.

[Polyimide Synthesis Example 1]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice water bath at 0 ° C., Jeffamine XTJ-542 (manufactured by Huntsman, weight average molecular weight 1000) 40 g, 1,3-bis (3-aminophenoxy) benzene (APB) 16.665 g, γ-butyrolactone (GBL) 60 g, 60 g of ethyl benzoate (BAEE), 20 g of toluene, 1.2 g of γ-valerolactone and 1.8 g of pyridine were added and stirred until uniform. Furthermore, 15.3 g of 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride (ODPA) and 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA) 17. 9 g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 5 hours, after which 0.57 g of aniline was added and cooled to room temperature. During the reaction, by-product water was dehydrated under reflux by azeotropy with toluene using a ball condenser equipped with a moisture separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide synthesis example 2]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice water bath at 0 ° C., 36 g of Jeffermine ED-600 (manufactured by Huntsman, weight average molecular weight 600), 10.817 g of 1,3-bis (3-aminophenoxy) benzene (APB), 60 g of γ-butyrolactone (GBL), 60 g of ethyl benzoate (BAEE), 20 g of toluene, 1.2 g of γ-valerolactone and 1.8 g of pyridine were added and stirred until uniform. Furthermore, 16.11 g of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and 17,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA) 17. 9 g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C., heated for 5 hours, and then cooled to room temperature. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide Synthesis Example 3]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice-water bath at 0 ° C., Jeffamine XTJ-542 (manufactured by Huntsman, weight average molecular weight 1000) 40 g, γ-butyrolactone (GBL) 60 g, ethyl benzoate (BAEE) 60 g, toluene 20 g, γ-valerolactone 12 g, pyridine 18 g And stirred until uniform. In addition, 18.365 g of 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 14.3 of 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA). 32g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 4 hours. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. After cooling the system to 60 ° C., 17.54 g of 1,3-bis (3-aminophenoxy) benzene (APB) was added. After 5 hours, 0.889 g of phthalic anhydride was added and cooled to room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide Synthesis Example 4]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice water bath at 0 ° C., Jeffamine XTJ-542 (manufactured by Huntsman, weight average molecular weight 1000) 40 g, 1,3-bis (3-aminophenoxy) benzene (APB) 14.033 g, γ-butyrolactone (GBL) 60 g, 60 g of ethyl benzoate (BAEE), 20 g of toluene, 12 g of γ-valerolactone and 18 g of pyridine were added and stirred until uniform. In addition, 18.365 g of 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 14.3 of 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA). 32g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 4 hours. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. After cooling the system to 60 ° C., 3.508 g of 1,3-bis (3-aminophenoxy) benzene (APB) was added. After 5 hours, 0.889 g of phthalic anhydride was added and cooled to room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide Synthesis Example 5]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice-water bath at 0 ° C., 36 g of Jeffermine ED-600 (manufactured by Huntsman, weight average molecular weight 600), 60 g of γ-butyrolactone (GBL), 60 g of ethyl benzoate (BAEE), 20 g of toluene, 12 g of γ-valerolactone, 18 g of pyridine And stirred until uniform. Further, 29.469 g of 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride (ODPA) was added little by little. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 4 hours. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. After cooling the system to 60 ° C., 11.694 g of 1,3-bis (3-aminophenoxy) benzene (APB) was added. After 5 hours, 0.889 g of phthalic anhydride was added and cooled to room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide Synthesis Example 6]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice-water bath at 0 ° C., Jeffamine XTJ-542 (manufactured by Huntsman, weight average molecular weight 1000) 25 g, 1,3-bis (3-aminophenoxy) benzene (APB) 18.419 g, γ-butyrolactone (GBL) 60 g, 60 g of ethyl benzoate (BAEE), 20 g of toluene, 12 g of γ-valerolactone and 18 g of pyridine were added and stirred until uniform. In addition, 18.365 g of 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 14.3 of 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA). 32g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 4 hours. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. After cooling the system to 60 ° C., 3.508 g of 1,3-bis (3-aminophenoxy) benzene (APB) was added. After 5 hours, 0.889 g of phthalic anhydride was added and cooled to room temperature. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Polyimide Synthesis Example 7]
A three-necked separable flask was equipped with a nitrogen condenser, a thermometer, and a ball condenser equipped with a moisture separation trap. In an ice water bath at 0 ° C., 27.774 g of 1,3-bis (3-aminophenoxy) benzene (APB), 60 g of γ-butyrolactone (GBL), 60 g of ethyl benzoate (BAEE), 20 g of toluene, 12 g of γ-valerolactone, 18 g of pyridine was added and stirred until uniform. Furthermore, 16.111 g of 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA) 17. 9 g was added in small portions. After stirring for 0.5 hour, the temperature was raised to 170 ° C. and heated for 5 hours, after which 0.57 g of aniline was added and cooled to room temperature. During the reaction, water produced as a by-product was dehydrated under reflux by azeotropy with toluene using a condenser tube with a water separation trap. After draining by-product water, the reflux was stopped and toluene was completely removed. Next, the product was pressure filtered through a 5 μm filter to obtain a polyimide varnish.

[Example 1]
To 100 parts by mass of the polyimide obtained in Synthesis Example 1 of polyimide, bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) Konishi 15 parts by mass of Chemical Industries, Ltd.) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 2]
20 parts by mass of methylolated melamine (Mw390: Nicalac MW-390, manufactured by Sanwa Chemical Co., Ltd.) was added as a thermal crosslinking agent to 100 parts by mass of the polyimide obtained in Polyimide Synthesis Example 1. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 3]
To 100 parts by mass of polyimide obtained in Synthesis Example 1 of polyimide, 20 parts by mass of hexamethylene diisocyanate block polyisocyanate (TPA-B: Duranate TPA-B80E manufactured by Asahi Kasei Chemicals) was added as a thermal crosslinking agent. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 4]
Bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) on 100 parts by mass of polyimide obtained in Polyimide Synthesis Example 2 Konishi 15 parts by mass of Chemical Industries, Ltd.) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size: 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 5]
Bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) on 100 parts by mass of polyimide obtained in Synthesis Example 3 of polyimide Konishi 10 parts by mass of Chemical Industries) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 6]
To 100 parts by mass of the polyimide obtained in Synthesis Example 4 of polyimide, bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) Konishi 20 parts by mass of Chemical Industries, Ltd.) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 7]
Bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) on 100 parts by mass of the polyimide obtained in Synthesis Example 5 of polyimide Konishi 10 parts by mass of Chemical Industries) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Example 8]
Bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) on 100 parts by mass of the polyimide obtained in Synthesis Example 6 of polyimide Konishi 25 parts by mass of Chemical Industries, Ltd.) was added, and the resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Comparative Example 1]
To 100 parts by mass of the polyimide obtained in Synthesis Example 7 of polyimide, bisphenol benzoxazine (Bis-F: Bis-F type benzoxazine) as a compound having a thermally crosslinkable functional group (hereinafter referred to as “thermal crosslinking agent”) Konishi 10 parts by mass of Chemical Industries) was added. As a flame retardant, 40 parts by mass of magnesium hydroxide (average secondary particle size 1.0 μm, manufactured by Tateho Chemical Industry Co., Ltd.) was added, and a resin composition was prepared so that the polyimide was 30% by mass. A cured film was prepared and evaluated.

[Comparative Example 2]
Other blends and the like were evaluated in the same manner as Example 1 except that the thermal crosslinking agent was not added.

[Comparative Example 3]
Other blends and the like were evaluated in the same manner as in Example 1 except that the type of thermal crosslinking agent was epoxy. In Table 1, epoxy is 1,4-butanediol diglycidyl ether. Table 1 shows the results of Examples 1 to 8 and Comparative Examples 1 to 3.

(Evaluation of surface protection film of printed circuit board)
Espanex M (manufactured by Nippon Steel Chemical Co., Ltd.) (insulating layer thickness 25 μm, conductor layer copper foil F2-WS (18 μm)) is used as the base material of the flexible printed wiring board, and line / space: 30 μm / 30 μm 50 μm / 50 μm, 100 μm / 100 μm, and 200 μm / 200 μm comb-shaped wiring boards were prepared. A part of the circuit board was coated with the resin composition of Example 1, and the uncoated part was subjected to electrolytic nickel-gold plating with a nickel thickness of about 5 μm and a gold thickness of about 0.05 μm. As a result of the micro fluorescent X-ray analysis, the penetration of the plating into the portion coated with the resin composition was less than 20 μm. In addition, the insulation between the circuits was confirmed to be good by an ohmmeter. Furthermore, ink was printed on the comb-shaped portion of the comb-shaped wiring board, and as a reliability test, the resistance was measured while being left for 1000 hours under conditions of DC 50 V, 85 ° C., and humidity 85%. As a result, all of them maintained a resistance exceeding 10 ⁹ Ω, and good results were obtained.

  Also, using a double-sided copper-clad plate of ESPANEX M (manufactured by Nippon Steel Chemical Co., Ltd.) (insulating layer thickness 25 μm, conductor layer copper foil F2-WS (18 μm)), a carbon dioxide laser via with a diameter of 100 μm was created. Then, a double-sided component-mounted circuit board was created after copper plating. The resin composition was applied to the part other than the part mounting part of this circuit board, and the part was fixed to the non-applied part with solder paste and then mounted in an IR reflow furnace at 260 ° C. I couldn't. In addition, the component non-mounting portion was bent at 180 degrees and incorporated in an electronic device, but it operated well for 1000 hours or more in an environment of 85 ° C., humidity 85%, DC 50V.

  As shown in Table 1, when a polyimide having a polyoxyalkyl ether group and a thermal crosslinking agent were included, warpage, resilience, heat resistance, and flame retardancy were satisfied. Furthermore, it was found that if the imidization ratio is 0.4 or more, good storage stability is exhibited. On the other hand, when there was no alkyl ether group in the polyimide structure, or when the thermal cross-linking agent according to the present invention was not included, various properties of warpage, resilience, heat resistance, and flame retardance could not be balanced.

  The present invention provides a heat-resistant resin composition useful as a surface protective film for semiconductor elements, an interlayer insulating film, a bonding sheet, a protective insulating film for printed wiring boards, a circuit board using the heat-resistant resin composition, an electronic component, and the like Applicable to.

Claims (10)

  The glass transition temperature after thermosetting is 50 ° C. to 120 ° C., the elastic modulus is 0.3 GPa to 1.4 GPa, and when immersed in a solder bath at 260 ° C. for 60 seconds, it satisfies that there is no swelling / burning, A resin composition characterized by having flame retardancy of VTM-1 or higher according to UL-94 standards.   The resin composition according to claim 1, wherein the change in the weight average molecular weight Mw is 10% or less after storage for 1 month. A resin composition comprising a polyimide precursor and a compound having a thermally crosslinkable functional group, wherein the polyimide precursor has at least one alkyl ether group represented by the general formula (1) The resin composition according to claim 1, comprising a polyimide precursor comprising an essential component.

(In the formula (1), R1, R2, R3, R4 and R5 represent an alkylene group having 1 to 5 carbon atoms, and R6, R7, R8, R9, R10, R11, R12, R13, R14 and R15. Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m, n, and q represent an integer of 1 to 20.)   4. The resin composition according to claim 3, wherein the compound having a thermally crosslinkable functional group is at least one compound selected from the group consisting of a triazine compound, a benzoxazine compound, and a blocked isocyanate compound.   The resin composition according to claim 3 or 4, wherein the content of the diamine represented by the general formula (1) with respect to all diamines is 25 mol% to 60 mol%.   The resin according to any one of claims 3 to 5, comprising a compound having the thermally crosslinkable functional group in a range of 5 to 40 parts by mass with respect to 100 parts by mass of the polyimide. Composition.   The resin composition according to claim 1, comprising a flame retardant.   A material for forming a protective film on a printed circuit board, comprising the resin composition according to claim 1.   A cured product obtained by thermosetting the resin composition according to any one of claims 1 to 7.   A circuit board comprising: a base material having wiring; and the cured product according to claim 9 covering a surface of the base material.