JP2005209692A - Thermosetting resin composition, prepreg for printed-wiring board and metal-clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting resin composition having incombustibility without using a halogen flame retarder and corresponding to an environmental problem having excellent heat resistance, a prepreg for a printed-wiring board, and a metal-clad laminate using the prepreg. <P>SOLUTION: The thermosetting resin composition contains (a) a non-halogenated epoxy resin having at least two or more of epoxy groups in one molecule, and (b) the polycondensation product of phenol and formaldehyde. The thermosetting resin composition further contains (c) a curing accelerator and (d) a high heat-resistant aluminum hydroxide. The thermosetting resin composition contains (d) high heat-resistant aluminum hydroxide of 50 to 150 pt. wt. to the organic-resin solid matter of 100 pt. wt. of the thermosetting resin composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermosetting resin composition, a prepreg for a printed wiring board, and a metal-clad laminate used for an electrical insulating material such as a printed wiring board.

  The epoxy resin laminate is produced by impregnating a glass woven fabric with a varnish solution of an epoxy resin composition, laminating prepregs that have been dried and B-staged, and heated and pressed. The epoxy resin laminate is provided with flame retardancy to ensure safety against fire and the like. Various methods are used for flame retardancy, but bromine compounds have been widely used so far due to their excellent flame retardancy. However, as the awareness of environmental destruction issues is increasing on a global scale, flame retardant systems that replace bromine compounds that generate corrosive bromine during incineration are being investigated.

On the other hand, Sn-Pb system has been mainly used for solder materials of mounted parts. However, investigation of solder materials that do not use Pb, which may contaminate the soil during disposal, etc., is also progressing. . Looking at reports on the Pb-free solder material, etc., the melting point is expected to rise, and the reflow temperature is likely to rise accordingly. Under these circumstances, future epoxy resin laminates will not require the use of bromine compounds, and at the same time will require higher heat resistance.
JP-A-11-124489 Japanese Patent Application Laid-Open No. 11-199753 Japanese Patent Laid-Open No. 11-181305

  As a flame retardant method instead of a bromine compound, addition of phosphorus or a nitrogen compound, introduction into a resin skeleton, or the like has been conventionally performed (see JP-A Nos. 11-12489 and 11-199975). . However, in order to ensure flame retardance with phosphorus and nitrogen, it is necessary to add a certain amount, which causes problems such as an increase in water absorption and a decrease in heat resistance. For this reason, there is a method in which metal hydrate is used in combination for the purpose of reducing the amount of phosphorus and nitrogen introduced. However, since metal hydrate traps a lot of water that exhibits a cooling effect during combustion, there is a problem that heat resistance is drastically lowered if a certain amount or more is added. This is due to the fact that the temperature at which the metal hydrate releases water is lower than the melting temperature of the solder. In the use of Pb-free solder, where the melting temperature of the solder is expected to become higher in the future. The problem related to the decrease in heat resistance becomes more remarkable.

  On the other hand, as a method for improving the heat resistance using a metal hydrate, there is a method using magnesium hydroxide having a relatively high water release temperature (about 340 ° C.) (see JP-A-11-181305). However, magnesium hydroxide has a problem of poor acid resistance.

  The object of the present invention is to use high heat-resistant aluminum hydroxide with a high temperature for releasing water as a flame retardant, so that it has flame resistance without using a halogen flame retardant and is excellent in heat resistance. It is providing the thermosetting resin composition of this, the prepreg for printed wiring boards, and the metal-clad laminated board using the same.

The present invention relates to each item described below.
(1) (a) a non-halogenated epoxy resin having at least two epoxy groups in one molecule, (b) a polycondensate of phenols and formaldehyde, (c) a curing accelerator and (d) highly heat-resistant water A thermosetting resin composition containing aluminum oxide, characterized in that it contains 50 to 150 parts by weight of (d) high heat-resistant aluminum hydroxide with respect to 100 parts by weight of the organic resin solid content of the thermosetting resin composition. A thermosetting resin composition.
(2) (a) The thermosetting resin according to (1), wherein the non-halogenated epoxy resin having at least two epoxy groups in one molecule is a glycidyl etherified product of a polycondensate of phenols and formaldehyde. Composition.
(3) A prepreg for a printed wiring board in which a glass woven fabric is impregnated with the thermosetting resin composition according to (1) or (2), heated and dried to form a B stage.
(4) A metal-clad laminate obtained by stacking at least one prepreg for a printed wiring board according to (3), placing a metal foil on one side or both sides thereof, and heating and pressing.

  If the thermosetting resin composition and prepreg according to the present invention are used, a metal-clad laminate for printed wiring boards having flame retardancy and excellent solder heat resistance can be obtained without using a halogen-based flame retardant. .

  The (a) non-halogenated epoxy resin having at least two epoxy groups in one molecule used in the present invention has two or more epoxy groups in the molecule, and any non-halogenated epoxy resin can be used. Epoxy resin may be used, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, diglycidyl etherified product of polyfunctional phenol, difunctional dihydric alcohol diester. Examples thereof include glycidyl etherified products, hydrogenated products thereof and the like, and these can be used alone or in combination of several kinds. In order to improve Tg and heat resistance of the cured thermosetting resin composition, (a) as a non-halogenated epoxy resin having at least two epoxy groups in one molecule, phenols and formaldehyde It is more preferable to use a glycidyl etherified product of a polycondensate. Examples of such glycidyl ether compounds include phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolak type epoxy resins, and the like, which can be used alone or in combination.

  (A) A polycondensate of phenols and formaldehyde, which is a curing agent for a non-halogenated epoxy resin having at least two epoxy groups in one molecule, is not limited in molecular weight. Examples of such polycondensates include phenol novolak resins, cresol novolak resins, bisphenol A novolak resins, and the like, and these can be used alone or in combination. The compounding amount of the polycondensate (curing agent) is as follows: (a) the epoxy of a non-halogenated epoxy resin having at least two epoxy groups in one molecule relative to the hydroxyl equivalent of the polycondensate (curing agent) to be used. It is preferable to blend so that the equivalent weight is hydroxyl equivalent / epoxy equivalent = 0.8 to 1.2 / 1.0. This is because when the hydroxyl equivalent of the polycondensation product (curing agent) is less than 0.8 and exceeds 1.2, the heat resistance becomes poor.

  Examples of the (c) curing accelerator used in the present invention include imidazole compounds and amines, but are not particularly limited. Examples of imidazole include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2- Methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-isopropylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-ethyl-4-methylimidazole trimellitate, 1-cyanoethyl-2-undecylimidazole trimellitate, 1 Cyanoethyl-2-phenylimidazole trimellitate, 1-cyanoethyl-2-phenyl-4,5-di (cyano ethoxymethyl) imidazole, and the like. Examples of amines include dimethylaminomethylphenol-2,4,6, -tri (dimethylaminomethyl) phenol, tri-2-ethylhexane salt of tri (dimethylaminomethyl) phenol, and the like. In addition, boron trifluoride complex compounds such as boron trifluoride / monoethylamine complex compound, boron trifluoride / triethylamine complex compound, boron trifluoride / piperidine complex compound, trifluoride Examples thereof include boron / n-butyl ether complex compounds, boron trifluoride / amine complex compounds, and the like. (c) The curing accelerator is 0 for a total of 100 parts by weight of (a) a non-halogenated epoxy resin having at least two epoxy groups in one molecule and (b) a polycondensate of phenols and formaldehyde. It is preferable to mix 1 to 10 parts by weight. If it is less than 0.1 part by weight, the effect on heat resistance is poor, and if it exceeds 10 parts by weight, the storage stability of the prepreg becomes poor.

  The (d) high heat-resistant aluminum hydroxide used as a flame retardant in the present invention is not particularly limited as long as the dehydration temperature for releasing 1% by weight of water is 250 ° C. or higher. If the 1% dehydration temperature is less than 250 ° C., the heat resistance of the substrate tends to be inferior. (D) The high heat-resistant aluminum hydroxide can use what is marketed, and brand name: ALH, Kawai lime industry make etc. are mentioned. This (d) high heat-resistant aluminum hydroxide is blended in an amount of 50 to 150 parts by weight with respect to 100 parts by weight of the organic resin solid content of the thermosetting resin composition. If it is less than 50 parts by weight, the flame retardant effect cannot be obtained, and if it exceeds 150 parts by weight, heat resistance and coating workability are reduced, and formability is deteriorated and peel strength is reduced.

  In the thermosetting resin composition of the present invention, the above (a), (b), (c) and (d) are essential components, and other inorganic fillers other than the high heat-resistant aluminum hydroxide, if necessary, or A colorant, an antioxidant, a coupling agent, a solvent, a reducing agent, an ultraviolet opaque agent, and the like may be added to the thermosetting resin composition. In particular, inorganic fillers can be suitably used to improve flame retardancy.

  A varnish obtained by blending the thermosetting resin composition of the present invention in a solvent is impregnated into a glass woven fabric and dried to obtain a B-staged prepreg for a printed wiring board. The type of the glass woven fabric used here is not particularly specified, and those having a thickness of 0.02 to 0.4 mm can be used according to the thickness of the target prepreg or laminate. The impregnation amount of the prepreg is shown as a resin component, and the resin component is a ratio of the total weight of the organic resin solid component of the thermosetting resin composition and the inorganic fillers to the total weight of the prepreg, and 30 to 90 % By weight is preferable, and 40 to 80% by weight is more preferable. The resin content is appropriately determined according to the performance of the target prepreg and the thickness of the insulating layer of the laminated board after lamination. The drying conditions for producing the prepreg can be freely selected in accordance with the desired prepreg characteristics within a range of a drying temperature of 60 to 200 ° C. and a drying time of 1 to 30 minutes.

  A prepreg obtained according to the thickness of the target laminate is laminated, a metal foil is laminated on one side or both sides, and heated and pressed to produce a metal-clad laminate. As the metal foil, copper foil or aluminum foil is mainly used, but other metal foil may be used. The thickness of the metal foil is usually 3 to 200 μm.

  The heating temperature during the production of the metal-clad laminate is 130 to 250 ° C., more preferably 160 to 200 ° C., and the pressure is 0.5 to 10 Mpa, more preferably 1 to 4 Mpa. It is determined appropriately depending on the thickness of the target laminate.

Hereinafter, the present invention will be specifically described based on examples.
(Example 1)
(A) As a non-halogenated epoxy resin having at least two epoxy groups in one molecule, bisphenol A novolak type epoxy resin (epoxy equivalent 205): 100 parts by weight (b) polycondensate of phenols and formaldehyde ( As a curing agent), bisphenol A type novolak resin (hydroxyl equivalent 118): 58 parts by weight (c) As a curing accelerator, 2-ethyl-4-methylimidazole: 0.2 parts by weight (d) As a high heat resistant aluminum hydroxide Product name: ALH (manufactured by Kawai Lime Industry Co., Ltd.): 190 parts by weight The above (a), (b), (c) and (d) are dissolved and dispersed in ethylene glycol monomethyl ether, and the nonvolatile content is 75% by weight. A varnish of a thermosetting resin composition was prepared. This varnish is impregnated into a 100 μm thick glass woven fabric (IPC product number # 2116 type), dried in a dryer at 180 ° C. for 6 minutes, and a prepreg for a printed wiring board in a B-stage state having a resin content of 60% by weight is obtained. Obtained.

(Example 2)
(A) Except that the non-halogenated epoxy resin having at least two epoxy groups in one molecule was changed to a 0-cresol novolak type epoxy resin (epoxy equivalent 210), B- A prepreg for a printed wiring board in a stage state was obtained.

(Comparative Example 1)
B-stage state in the same manner as in Example 1 except that instead of (d) the high heat resistant aluminum hydroxide in Example 1, a general aluminum hydroxide having a 1% dehydration temperature of 230 ° C. or lower was used. The prepreg for printed wiring boards was obtained.

(Comparative Example 2)
As in Example 1, except that 58 parts by weight of bisphenol A type novolak resin was changed to 4 parts by weight of dicyandiamide as the curing agent in Example 1, and (d) the blending amount of the high heat-resistant aluminum hydroxide was changed to 125 parts by weight. Thus, a prepreg for a printed wiring board in a B-stage state was obtained.

(Comparative Example 3)
A prepreg for a printed wiring board in a B-stage state was obtained in the same manner as in Example 1 except that the amount of (d) the high heat resistant aluminum hydroxide in Example 1 was changed to 70 parts by weight.

(Comparative Example 4)
A prepreg for a printed wiring board in a B-stage state was obtained in the same manner as in Example 1 except that the blending amount of (d) the high heat-resistant aluminum hydroxide in Example 1 was changed to 250 parts by weight.

(Manufacturing method of metal-clad laminate)
Four printed wiring board prepregs obtained in Examples 1 and 2 and Comparative Examples 1, 2, 3 and 4 were stacked, and a copper foil having a thickness of 18 μm was disposed on both sides thereof, and the pressure was 3 Mpa, and the temperature was 185 ° C. A double-sided copper-clad laminate (metal-clad laminate) was obtained by heating and pressing for a minute.

The thus obtained double-sided copper foil-clad laminate was subjected to Tg, UL-94 flammability test and substrate solder heat resistance test. The results are shown in Table 1. The Tg was measured using a DuPont TMA. The substrate solder heat resistance is 288 ° C. solder after the moisture absorption treatment described in Table 1 (PCT treatment: 121 ° C., held in a pressure cooker treatment apparatus of 2.13 × 10 ⁵ Pa for 1 hour, 3 hours, 5 hours). It is the result of having observed the double-sided copper foil clad laminated board immersed in the tank for 20 seconds. Each symbol means ◯: no change, Δ: occurrence of measling, ×: occurrence of blistering, and three symbols respectively show the results of evaluation using three test pieces.

From Table 1, the metal-clad laminate using the printed wiring board prepreg of the present invention achieves V-0 in the UL-94 flammability test without using a halogen-based flame retardant, and is excellent in heat resistance. I understand that. On the other hand, the comparative example 1 using the general aluminum hydroxide whose 1% dehydration temperature of aluminum hydroxide is 230 degreeC resulted in inferior heat resistance. In Comparative Example 2 using the dicyandiamide curing agent, the results were poor in flame retardancy and heat resistance. Further, (d) Comparative Example 3 in which the blending amount of the high heat-resistant aluminum hydroxide is less than 50 parts by weight with respect to 100 parts by weight of the organic resin solid content is inferior in flame retardancy, and the blending amount is 100 parts by weight of the organic resin solids. On the other hand, Comparative Example 4 exceeding 150 parts by weight resulted in inferior heat resistance.

Claims (4)

  (A) a non-halogenated epoxy resin having at least two epoxy groups in one molecule, (b) a polycondensate of phenols and formaldehyde, (c) a curing accelerator, and (d) a high heat resistant aluminum hydroxide. A thermosetting resin composition comprising 50 to 150 parts by weight of (d) a high heat resistant aluminum hydroxide with respect to 100 parts by weight of the organic resin solid content of the thermosetting resin composition. Curable resin composition.   (A) The thermosetting resin composition according to claim 1, wherein the non-halogenated epoxy resin having at least two epoxy groups in one molecule is a glycidyl etherified product of a polycondensate of phenols and formaldehyde.   A prepreg for a printed wiring board obtained by impregnating a glass woven fabric with the thermosetting resin composition according to claim 1 or 2 and heating and drying to form a B-stage. A metal-clad laminate obtained by stacking at least one prepreg for a printed wiring board according to claim 3, placing a metal foil on one or both sides thereof, and heating and pressing.