JP2005120173A - Curable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition which has a good moldability, gives a cured material having a low dielectricity, high heat resistance and good heat resistance after absorbing moisture. <P>SOLUTION: In the curable resin composition, 1-30 pts.wt. of (b) a crosslinked polystyrene powder is mixed with 100 pts.wt. of (a) a cyanate resin as the indispensable component. Preferably (c) a polyphenylene ether-based resin with a weight average molecular weight of 500-3,000 and/or (d) a polycarbonate resin and/or (e) silica powder are added to the curable resin composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a curable resin composition useful for a printed wiring board material, and a cured product obtained from the present curable resin composition is excellent in dielectric characteristics, and is therefore suitable for a printed wiring board material for high frequency applications. In particular, it is suitably used for printed wiring board materials for semiconductor plastic packages or mother boards for mounting semiconductor chips.

In recent years, with the progress of higher density in electronic equipment, in order to cope with finer wiring patterns, smaller through-hole diameters, higher signal propagation speeds and higher signal frequencies, low dielectric properties in the high frequency region, especially There is an increasing demand for printed wiring board materials having low dielectric loss tangent and high heat resistance. Polyimide resins, cyanate ester resins, bismaleimide-triazine (BT) resins, unsaturated group-containing polyphenylene ether resins, etc. have been put to practical use as resins having both low dielectric loss tangent and high heat resistance. For the purpose of characterization, various improvement methods based on these resins have been proposed. Examples of using a cyanate ester resin together include a laminated plate using a high molecular weight polyphenylene ether resin together with a cyanate ester resin (for example, see Patent Document 1), and a low molecular weight aromatic vinyl compound oligomer to the cyanate ester resin. A curable resin composition to be used in combination (see, for example, Patent Document 2) has been proposed, but the former laminate is inferior in moldability during multilayering and heat resistance after moisture absorption, and the latter resin composition is The low molecular weight aromatic vinyl compound tends to evaporate during heating, and the heat resistance is lowered, and further improvement is necessary.
Japanese Patent Publication No. 63-49695 Japanese Patent Publication No. 2674080

  The present invention provides a curable resin composition having good moldability, and the obtained cured product has low dielectric properties, high heat resistance, and excellent heat resistance after moisture absorption.

  The present invention is a curable resin composition comprising 1 to 30 parts by weight of a crosslinked polystyrene (b) powder as an essential component with respect to 100 parts by weight of a cyanate ester resin (a), preferably the curable resin composition A curable resin composition comprising a polyphenylene ether resin (c) having a weight average molecular weight of 500 to 3000 and / or a polycarbonate resin (d) and / or silica powder (e). In the curable resin composition of the present invention, the obtained cured product has a low dielectric property and high heat resistance, and when applied to a printed wiring board, a laminate material having excellent moldability and heat resistance after moisture absorption is obtained. can get.

  The cured product obtained from the curable resin composition of the present invention has a low dielectric property and high heat resistance, and in a printed wiring board application, a laminated material excellent in heat resistance and moldability after moisture absorption was obtained. .

  The cyanate ester resin (a) used in the present invention is not particularly limited as long as it is a compound having two or more cyanato groups in the molecule. Specific examples include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2 , 6- or 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanato Phenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) ) Sulfone, tris (4-cyanatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reaction of novolac with cyanogen halide.

  In addition to these, cyanate ester compounds described in JP-B-41-1928, 43-18468, 44-4791, 45-11712, 46-41112, 47-26853, and JP-A-51-63149 are also included. Can be used. In addition, a prepolymer having a triazine ring formed by trimerization of cyanate groups of these cyanate ester compounds and having a weight average molecular weight of 400 to 6,000 is used. This prepolymer is obtained by polymerizing the above-mentioned cyanate ester compound using, for example, acids such as mineral acids and Lewis acids; bases such as sodium alcoholates and tertiary amines; salts such as sodium carbonate and the like as catalysts. It is done. This prepolymer also includes a partially unreacted monomer, which is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the application of the present invention. These are used alone or in combination of two or more.

  The crosslinked polystyrene (b) used in the present invention is not particularly limited as long as it is a copolymer of polystyrene or styrene and another aromatic vinyl compound having a crosslinked structure. Examples of other aromatic vinyl compounds include, but are not limited to, α-methylstyrene, vinyltoluene, divinylbenzene, chlorostyrene, bromostyrene, and the like. Examples of the method for producing the crosslinked polystyrene (b) include, but are not limited to, copolymerization with a divinyl compound, combined use of a peroxide and radiation treatment. Specifically, a method using suspension polymerization or solution polymerization in the presence of a polymerization catalyst using a styrene monomer and divinylbenzene can be mentioned. The shape of the crosslinked polystyrene (b) powder used in the present invention is not particularly limited, but for example, any shape such as a spherical shape and an indefinite shape can be used, and the particle diameter of the crosslinked polystyrene (b) powder is not particularly limited. However, those having an average particle diameter of 0.2 to 10 μm are preferably used. The blending amount of the crosslinked polystyrene (b) powder is 1 to 30 parts by weight, preferably 5 to 20 parts by weight with respect to 100 parts by weight of the cyanate ester resin (a).

  In the present invention, the polyphenylene ether resin (c) preferably used is not particularly limited as long as it is a polyphenylene ether resin having a weight average molecular weight of 500 to 3000 or a terminal-modified product thereof. Examples of the terminal modification of the compound having a polyphenylene ether structure include terminal epoxidized polyphenylene ether resin, terminal cyanated polyphenylene ether resin, terminal styrenated polyphenylene ether resin, terminal (meth) acrylated polyphenylene ether resin, and the like. One type or two or more types are used in appropriate combination. The molecular weight of the polyphenylene ether resin (c) is 500 to 3000 in terms of weight average molecular weight, and more preferably 600 to 2000. The blending amount of the polyphenylene ether resin (c) is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the cyanate ester resin (a).

  In the present invention, the polycarbonate resin (d) preferably used is not particularly limited as long as it is a compound having a polycarbonate structure, but a halogenated polycarbonate is preferably used. The molecular weight of the polycarbonate resin (d) is not particularly limited, but a weight average molecular weight of 500 to 3000 is preferable. The blending amount of the polycarbonate resin (d) is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the cyanate ester resin (a).

  A combination of epoxy resins is suitable for the curable resin composition of the present invention. These epoxy resins are not particularly limited as long as they are compounds having two or more epoxy groups in one molecule. Specifically, double bonds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, butadiene, pentadiene, vinylcyclohexene, dicyclopentyl ether, etc. Epoxidized polyepoxy compounds; polyglycidyl compounds obtained by reaction of polyols, hydroxyl group-containing silicon resins and epichlorohydrin, and the like. These bromine and phosphorus compounds can also be used. These can be used alone or in combination of two or more.

  In the present invention, an organic solvent is used as necessary, but the type is not particularly limited as long as it is compatible with the resin composition used. Typical examples include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; polar solvents such as dimethylacetamide and dimethylformamide; and aromatic hydrocarbon solvents such as toluene and xylene. It is also possible to use a mixture of the above as appropriate.

  In the thermosetting resin composition of the present invention, various additives can be blended as desired within a range where the original properties of the composition are not impaired. These additives include polyfunctional maleimides; polymerizable double bond-containing monomers such as unsaturated polyesters and prepolymers thereof; polybutadiene, epoxidized butadiene, maleated butadiene, butadiene-acrylonitrile copolymers, poly Low molecular weight liquid to high molecular weight elastic rubber such as chloroprene, butadiene-styrene copolymer, polyisoprene, butyl rubber, fluorine rubber, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methylpentene, polystyrene, AS resin , ABS resin, MBS resin, styrene-isoprene rubber, polyethylene-propylene copolymer, 4-fluoroethylene-6-fluoroethylene copolymers; high molecular weight prepolymers or oligomers such as polysulfone, polyester, polyphenylene sulfide; For example, polyurethane Shown and used as appropriate. In addition, other known inorganic and organic fillers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, thixotropic properties Various additives such as an imparting agent are used in appropriate combination as desired.

  The curable resin composition of the present invention is cured by heating, but a known thermosetting catalyst can be used when the curing rate is slow and the workability, economy, etc. are inferior. The amount used is 0.005 to 5 parts by weight, preferably 0.01 to 3 parts by weight, per 100 parts by weight of the curable resin.

  The silica powder (e) preferably used in the present invention is not particularly limited as long as it is an inorganic powder mainly composed of silicon dioxide. For example, pulverized silica powder, fused silica powder, synthetic silica A powder etc. are mentioned, It uses 1 type or in combination of 2 or more types as appropriate. As the shape of the silica powder (e), for example, any of spherical, indefinite shape, etc. can be used. ˜5 μm is preferred. The blending amount of the silica powder (e) is not particularly limited, but is 5 to 250 parts by weight, preferably 7 to 150 parts by weight with respect to 100 parts by weight of the curable resin composition (solid content).

  The curable resin composition of the present invention can be applied to molded products, molding materials, paints, adhesives, laminates, and the like, and is particularly useful for printed wiring board materials such as copper-clad laminates and multilayer boards. Yes, as a prepreg combined with a substrate, it can be applied to one side of a copper foil or a release film and dried to form a B-stage resin composition layer for an ordinary laminated material, and used as a laminated material for build-up.

  As a method for producing a copper-clad laminate suitable for the use of the curable resin composition of the present invention, an inorganic or organic substrate is impregnated with the curable resin composition of the present invention and dried to form a B stage to produce a prepreg. To do. Next, a predetermined number of the prepregs are stacked, a copper foil is disposed on at least one surface, and laminated by heating and pressing, preferably under vacuum, to obtain a copper-clad laminate. The thickness of the copper foil is preferably 3 to 35 μm.

  A method for producing a multilayer board suitable as a use of the curable resin composition of the present invention is to make a through hole in the copper-clad laminate with a laser, a mechanical drill, etc., to form a circuit, and to produce an inner layer board. After the copper foil surface treatment, on at least one side, a B-stage base material reinforced prepreg, or a B-stage resin composition sheet without a base material, a copper foil with a B-stage resin, a resin layer by coating, and the like are arranged. A copper foil is placed on the outside and laminated by heating and pressing, preferably under vacuum, to form a multilayer board. Further, a known method can be applied such as using a plurality of inner layer plates, putting a prepreg between and outside the inner layer plates, laminating and forming a copper foil on the outermost layer, and forming a multilayer plate.

As a molding condition of the copper-clad laminate, a general method for laminates for printed wiring boards and multilayer boards can be applied. For example, a multistage press, a multistage vacuum press, continuous molding, an autoclave molding machine, etc. are used, and the temperature is generally 100 to 300 ° C., the pressure is 2 to 100 kgf / cm ² , and the heating time is 0.1 to 5 hours.

 The present invention will be specifically described below with reference to examples and comparative examples. “Part” represents part by weight.

Synthesis example (synthesis of terminal styrenated polyphenylene ether resin A)
480.0 g of phenylene ether oligomer obtained by reacting 1 mol of 4,4'-methylenebis (2,6-dimethylphenol) and 3 mol of 2,6-dimethylphenol in the presence of CuCl and di-n-butylamine, vinylbenzyl 260.2 g of chloride (CMS-P; manufactured by Seimi Chemical Co., Ltd.), 2000 g of tetrahydrofuran, 240.1 g of potassium carbonate, and 60.0 g of 18-crown-6-ether were mixed and reacted at 30 ° C. for 6 hours. Concentrate, dilute with toluene, wash with water, concentrate the organic layer and drop into methanol to solidify, collect the solid by filtration, vacuum dry and terminal styrenated polyphenylene ether resin A (weight average molecular weight: 1420 )

Example 1
900 parts of 2,2-bis (4-cyanatophenyl) propane and 100 parts of bis (4-maleimidophenyl) methane were melted at 150 ° C. and reacted for 4 hours with stirring to obtain a monomer-containing prepolymer. After dissolving this in a mixed solvent of methyl ethyl ketone and dimethylformamide, 200 parts of bisphenol A type epoxy resin (Epicoat 1001, manufactured by Japan Epoxy Resin Co., Ltd.), cross-linked polystyrene powder (SBX-6, average particle size: 6 μm, Sekisui) 120 parts of Nippon Seisaku Kogyo Co., Ltd. and 0.4 parts of zinc octylate were added and mixed uniformly to make varnish B. This varnish B is impregnated into a 100 μm thick NE glass woven fabric, dried at 170 ° C., gelation time (at 170 ° C.) 120 seconds, resin composition content 45 wt% prepreg C, and resin composition A prepreg D having a content of 55% by weight and a gel time of 145 seconds was produced. Four prepregs C are stacked, and 35μm thick electrolytic copper foil is placed on the top and bottom surfaces of the prepreg C. Laminate molding is performed at 200 ° C, 20kgf / cm ² , 30mmHg or less for 2 hours, and 400μm thick double-sided copper Plate E was produced. Next, a circuit is formed on the double-sided copper-clad laminate E, the conductor is treated with black copper oxide, one prepreg D is placed on each side, and a 12 μm electrolytic copper foil is placed on the outside, as above. A four-layer plate was produced by laminating to the above. The evaluation results are shown in Table 1.

Example 2
1000 parts of 2,2-bis (4-cyanatophenyl) ether was heated and melted at 150 ° C. and reacted for 4.5 hours with stirring to obtain a monomer-containing prepolymer. After this was dissolved in methyl ethyl ketone, 300 parts of the above-mentioned terminal styrenated polyphenylene ether resin A, 300 parts of crosslinked polystyrene powder (SBX-6), and 0.2 part of zinc octylate were added and mixed uniformly to obtain Varnish F. This varnish F is impregnated into E glass woven fabric with a thickness of 50μm, dried at 160 ° C, resin flow (100x100mm, 5 layers, 200 ° C, 40kgf / cm ² , 5 minutes) 11%, resin composition A prepreg G having a content of 60% by weight, a prepreg H having a resin flow (same as above) of 14% and a resin composition content of 70% by weight was prepared. Eight prepregs G are stacked, and 35μm thick electrolytic copper foil is placed on the top and bottom surfaces of the prepreg G. Laminate molding is performed at 220 ° C, 30kgf / cm ² , 30mmHg or less for 2 hours. Plate I was prepared. A circuit is formed on this double-sided copper clad laminate I, the conductor is treated with black copper oxide, two prepregs H are arranged on both sides, and an electrolytic copper foil having a thickness of 12 μm is arranged on the outside. In the same manner, a four-layer plate was produced by laminate molding. The evaluation results are shown in Table 1.

Example 3
1000 parts by weight of spherical silica powder (FB-3SDC, average particle size: 3 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 1300 parts of the solid content of varnish B of Example 1, and the mixture was uniformly stirred and mixed. Got. This varnish J is impregnated into a 100 μm thick NE glass woven fabric, dried at 170 ° C., gelation time (at 170 ° C.) 132 seconds, resin composition content 47% by weight of prepreg K, and resin composition A prepreg L having a content of 58% by weight and a gel time of 151 seconds was produced. An electrolytic copper foil having a thickness of 18 μm was placed on the upper and lower surfaces of the four prepregs K, and a double-sided copper clad laminate M was produced in the same manner as in Example 1. A circuit is formed on this double-sided copper clad laminate M, the conductor is treated with black copper oxide, one prepreg L is placed on each side, and 12μm electrolytic copper foil is placed on the outside. A four-layer board was produced by molding. The evaluation results are shown in Table 1.

Example 4
To 1000 parts of solid content of varnish J obtained in Example 3, 300 parts of brominated polycarbonate oligomer (FG8500, Br content: 58 wt%, weight average molecular weight: 1500, manufactured by Teijin Chemicals Ltd.) was uniformly mixed. Thus, varnish N was produced. This varnish N is impregnated into a liquid crystal polyester nonwoven fabric (MBBK, manufactured by Kuraray Co., Ltd.) with a thickness of 40 μm, dried at 150 ° C., and a resin composition content of 50% by weight, gelation time (133 seconds at 170 ° C.) Prepreg O was prepared. An electrolytic copper foil having a thickness of 12 μm was placed on the upper and lower surfaces where six prepregs O were stacked, and laminate-molded in the same manner as in Example 1 to produce a double-sided copper-clad laminate. The evaluation results are shown in Table 1.

Comparative Example 1
In Example 1, in place of 300 parts of the crosslinked polystyrene powder, except that 300 parts of polystyrene oligomer (Picolastec A5, manufactured by Rika Hercules Co., Ltd.) was used, the same procedure as in Example 1 was carried out (when dried at 170 ° C. A phenomenon in which polystyrene oligomers were scattered was observed). The evaluation results are shown in Table 1.

Comparative Example 2
In Example 2, instead of using the crosslinked polystyrene powder, instead of using 300 parts of the terminal styrenated polyphenylene ether resin A, 300 parts of a polyphenylene ether resin (weight average molecular weight 8200) dissolved in a toluene solution was used. In the same manner as in Example 2, a four-layer plate was produced. The evaluation results are shown in Table 1.

Table 1
Example Comparison example
Item 1 2 3 4 1 2
Formability ○ ○ ○ − △ ×
Glass transition temperature (℃) 224 228 225 220 189 208
Dielectric constant (1GHz) 3.3 3.7 3.8 3.4 3.4 3.7
Dissipation factor (1GHz) 0.004 0.003 0.004 0.004 0.005 0.005
Moisture absorption heat resistance No abnormality No abnormality No abnormality No abnormality No abnormality No swelling

<Measurement method>
1) Formability: The embedding property of the inner layer pattern of the four-layer board is visually determined. (○: No void △: Small void ×: Large void)
2) Glass transition temperature: Measured by DMA method according to JIS C 6481 after removing copper foil from double-sided copper-clad laminate.
3) Dielectric property: Measured by cavity resonance perturbation method after removing copper foil from double-sided copper-clad laminate. (Measurement frequency 1GHz)
4) Moisture absorption heat resistance: The specimen (50x50mm) was subjected to moisture absorption treatment at 121 ° C and 2kgf / cm ² for 2 hours, and visually checked for abnormal appearance after being immersed in solder at 260 ° C for 30 seconds.

Claims (4)

A curable resin composition comprising 1 to 30 parts by weight of a crosslinked polystyrene (b)) powder as an essential component per 100 parts by weight of a cyanate ester resin (a). The curable resin composition according to claim 1, wherein a polyphenylene ether resin (c) having a weight average molecular weight of 500 to 3000 is blended with the curable resin composition. The curable resin composition of Claim 1 or 2 which mix | blended polycarbonate resin (d) with this curable resin composition. A curable resin composition comprising the curable resin composition according to any one of claims 1 to 3 and a silica powder (e).