JP2006028274A - Epoxy resin composition and prepreg using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an epoxy resin composition that has excellent dimensional stability of prepreg when used as a resin material for prepreg, controls peeling off of an inorganic flame retardant while having sufficient flame retardance and has heat resistance dealing with treatment temperature of lead-free solder and prepreg using the composition. <P>SOLUTION: The epoxy resin composition is obtained by adding at least 20-50 parts wt. of a phenoxy resin and/or acrylonitrile-butadiene rubber and 100-300 parts wt. of magnesium hydroxide to 100 parts wt. of a dicyclopentadiene type epoxy resin and/or a naphthalene type epoxy resin. The prepreg is obtained by impregnating or coating a substrate with the epoxy resin composition, drying and semicuring the epoxy resin composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an epoxy resin composition and a prepreg using the same, and more particularly to an epoxy resin composition suitable as a resin material for a prepreg used in a multilayer printed wiring board and a prepreg using the same. .

  In general, a multilayer printed wiring board is used in order to increase the mounting density of electric / electronic components. This type of multilayer printed wiring board is formed by laminating a plurality of printed wiring boards whose surfaces are covered with a cover lay film with prepregs sandwiched between the printed wiring boards, and pressing the laminated body with a predetermined portion. It is manufactured by, for example, opening and plating and conducting between predetermined wiring patterns of each printed wiring board.

  In recent years, this type of multilayer printed wiring board has been made higher in density and multilayer. For this reason, prepregs that are inevitably used in multilayer printed wiring boards are increasingly required to improve their characteristics, particularly to improve dimensional stability such as shrinkage and thermal expansion.

  Conventionally, as a resin material for a prepreg, an epoxy resin composition in which a flame retardant is added to an epoxy resin excellent in dimensional stability and adhesiveness is known.

  As the epoxy resin in the epoxy resin composition, specifically, a phenol novolac type epoxy resin having a relatively excellent flame retardancy because of having dimensional stability and a benzene ring has been used recently. In order to obtain higher dimensional stability, an epoxy resin composition using a dicyclopentadiene type epoxy resin having a rigid main chain rather than a phenol novolac type epoxy resin has been studied.

  In addition, as flame retardants in the above epoxy resin composition, halogen flame retardants and phosphorus flame retardants having a high flame retardant effect with a small addition amount have been used, but recently, consideration for the global environment Therefore, alternatives to inorganic flame retardants that do not contain halogen or phosphorus are being studied.

  Under such circumstances, for example, Patent Document 1 describes an epoxy resin composition obtained by adding a large amount of aluminum hydroxide as an inorganic flame retardant to a modified dicyclopentadiene type epoxy resin and a prepreg using the same. Has been.

  On the other hand, lead solder has been used as a solder material for mounting a semiconductor element on the printed wiring board. However, in consideration of the global environment as in the case of the flame retardant, lead has recently been used. Lead-free solder whose processing temperature is about 20 ° C. higher than that of solder (processing temperature is about 280 ° C.) has been used.

JP 2001-122949 A

  However, the conventional epoxy resin composition and prepreg have the following problems.

  That is, the dicyclopentadiene type epoxy resin, when used as a resin material for a prepreg, is excellent in dimensional stability of the prepreg, but is inferior in flame retardancy compared to a phenol novolac type epoxy resin having a benzene ring. . Moreover, inorganic flame retardants, such as aluminum hydroxide, are inferior to a flame retardance compared with the halogenated flame retardant and phosphorus flame retardant of the same addition amount.

  Therefore, if it is going to give sufficient flame retardance which satisfies 94-V0 of UL specification using these, it is necessary to add a large amount of inorganic flame retardants as described in patent documents 1, for example. was there.

  However, when a large amount of an inorganic flame retardant is added to an epoxy resin having a rigid main chain, the inorganic flame retardant peels off from the prepreg surface in the manufacturing process of the multilayer printed wiring board, and this causes the base material of the coverlay film to be peeled off. There was a problem that the adhesiveness with the prepreg deteriorated.

  Further, in the punching process performed when the multilayer printed wiring board is laminated, the inorganic flame retardant is peeled off from the edge portion of the prepreg after the punching, thereby causing a problem that the product failure of the multilayer printed wiring board is likely to occur. .

  In addition, when a multilayer printed wiring board is manufactured with a prepreg using an epoxy resin composition added with aluminum hydroxide as an inorganic flame retardant as a resin material, a semiconductor element is mounted on the multilayer printed wiring board using lead-free solder. When trying to do so, there is a problem that aluminum hydroxide causes a dehydration endothermic reaction at the processing temperature, thereby generating gas and causing blistering on the substrate surface. This type of blistering occurs particularly on conductor wiring that lacks gas permeability.

  Therefore, the problem to be solved by the present invention is excellent in dimensional stability of the prepreg when used as a resin material for prepreg, and can suppress peeling of the inorganic flame retardant while having sufficient flame retardancy, Furthermore, it is providing the epoxy resin composition which has heat resistance which can respond to the processing temperature of lead-free solder, and a prepreg using the same.

  In order to solve the above-mentioned problems, the epoxy resin composition according to the present invention has a phenoxy resin and / or acrylonitrile-butadiene rubber in an amount of 20 to 50 weights with respect to 100 parts by weight of a dicyclopentadiene type epoxy resin and / or a naphthalene type epoxy resin. And at least 100 to 300 parts by weight of magnesium hydroxide.

  The gist of the prepreg according to the present invention is that the epoxy resin composition is impregnated or coated on a base material and dried and semi-cured.

  According to the epoxy resin composition, since magnesium hydroxide is used as the inorganic flame retardant, it is friendly to the global environment as compared with the case where a halogen flame retardant and a phosphorus flame retardant are used. Moreover, since it contains a large amount of magnesium hydroxide, it has sufficient flame retardancy.

  Even if it contains a large amount of magnesium hydroxide, it contains a specific amount of phenoxy resin and / or acrylonitrile-butadiene rubber as a modifier, so that magnesium hydroxide is easily embedded in the resin, Magnesium does not peel off easily.

  Moreover, since magnesium hydroxide whose dehydration endothermic reaction start temperature is 20 ° C. or more higher than that of aluminum hydroxide is used, it has heat resistance that can cope with the processing temperature of lead-free solder.

  On the other hand, according to the prepreg, since the epoxy resin composition is used, the dimensional stability and flame retardancy are excellent.

  Moreover, since magnesium hydroxide is difficult to peel off from the prepreg, the adhesive property between the base material of the coverlay film and the prepreg is excellent in the manufacturing process of the multilayer printed wiring board. Moreover, the product defect of the multilayer printed wiring board resulting from peeling off of magnesium hydroxide can also be suppressed.

  Further, in the manufacturing process of the multilayer printed wiring board, even if it is exposed to the processing temperature of lead-free solder, it is difficult for gas to be generated.

  Hereinafter, embodiments of the present invention will be described in detail. The epoxy resin composition according to the present invention (hereinafter referred to as “the present composition”) is a specific amount of phenoxy resin and / or acrylonitrile-butadiene rubber relative to dicyclopentadiene type epoxy resin and / or naphthalene type epoxy resin. And containing at least magnesium hydroxide.

  In the present composition, the dicyclopentadiene type epoxy resin refers to an epoxy resin having a dicyclopentadiene skeleton in the molecule. The naphthalene type epoxy resin means an epoxy resin having a naphthalene skeleton in the molecule.

  This composition may contain either a dicyclopentadiene type epoxy resin or a naphthalene type epoxy resin, or may contain both a dicyclopentadiene type epoxy resin and a naphthalene type epoxy resin.

  Two or more kinds of dicyclopentadiene type epoxy resins and naphthalene type epoxy resins may be mixed.

  Specific examples of the dicyclopentadiene type epoxy resin include those represented by the following chemical formula (1).

  Specific examples of the naphthalene type epoxy resin include those represented by the following chemical formulas 2 to 9. Preferably, what is represented by Chemical formula 9 is used.

  In the present composition, phenoxy resin and acrylonitrile-butadiene rubber (hereinafter referred to as “NBR”) are used as a resin modifier, mainly for making it easy to embed magnesium hydroxide in the epoxy resin. To be added.

  In the present composition, either one of phenoxy resin and NBR may be contained, or both of phenoxy resin and NBR may be contained. Preferably, it contains a phenoxy resin because it is compatible with the epoxy resin and has excellent heat resistance.

  The phenoxy resin is a polyether obtained from bisphenol A and epichlorohydrin.

  Moreover, since the said phenoxy resin is excellent in a flame retardance etc., the phosphorus containing phenoxy resin containing phosphorus may be sufficient.

  On the other hand, NBR may be used as it is, but from the viewpoint of compatibility with the epoxy resin, it is preferably a terminal-modified NBR whose terminal is modified with a functional group such as a carboxyl group or an amino group. The NBR property may be liquid. Of course, it may be a terminal-modified liquid NBR in which both are combined.

  In this composition, magnesium hydroxide is used as an inorganic flame retardant, and is mainly added to impart flame retardancy to the epoxy resin.

  In the present composition, the surface of the magnesium hydroxide particles may be surface-treated with a coupling agent such as silane or titanate such as epoxy silane, amino silane, acrylic silane, or vinyl silane. If surface treatment is applied to magnesium hydroxide, it becomes easier to be embedded in the resin, and there is an advantage that the magnesium hydroxide can be less peeled off.

  This composition is 20 to 50 parts by weight of phenoxy resin and / or NBR, preferably 25 to 45 parts by weight, and 100 to 300 parts by weight of magnesium hydroxide, preferably 100 parts by weight of the epoxy resin. It is contained within the range of 150 to 250 parts by weight.

  When the content of the phenoxy resin and / or NBR is less than 20 parts by weight, it is not preferable because a sufficient modification effect cannot be obtained and the magnesium hydroxide tends to peel off. In addition, when the content of phenoxy resin and / or NBR exceeds 50 parts by weight, the adhesion between the base material of the coverlay film and the prepreg is deteriorated when used as a resin material for prepreg (the peel strength is reduced). This is not preferable because a tendency is seen.

  On the other hand, if the content of magnesium hydroxide is less than 100 parts by weight, it is not preferable because sufficient flame retardancy tends to be obtained. On the other hand, if the content of magnesium hydroxide exceeds 300 parts by weight, it is not preferable because the magnesium hydroxide peels off or costs increase.

  In the present composition, in addition to the above components, additives that are generally added as necessary, for example, curing agents, curing accelerators, inorganic flame retardants other than magnesium hydroxide, flame retardant aids, inorganic 1 type, or 2 or more types may be added in the range which does not impair the physical property of this composition, such as a filler, antioxidant, and a coloring agent.

  Moreover, it does not specifically limit as a manufacturing method of this composition, A well-known manufacturing method can be used. For example, the present composition can be produced by blending the above components and solvent, if necessary, other additives, etc., and mixing them uniformly with a mixer, blender, etc. Absent.

  Next, a prepreg using the present composition (hereinafter referred to as “the present prepreg”) will be described. The present prepreg is obtained by impregnating or coating the above-described composition on a substrate and drying and semi-curing the composition.

  In the present prepreg, specific examples of the substrate include glass cloth, glass nonwoven fabric, glass paper, paper, organic fibers including organic nonwoven fabric, and the like, and are not particularly limited. Note that the shape and thickness of the base material can be appropriately changed in consideration of the shape of the target multilayer printed wiring board.

  Moreover, it does not specifically limit as a manufacturing method of this prepreg, A well-known manufacturing method can be used. For example, after impregnating or applying the present composition to the substrate, the prepreg in a semi-cured state (B stage) is produced by drying in a dryer at about 120 to 200 ° C. for about 0.5 to 10 minutes. There is no particular limitation.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Test material and manufacturer)
The test materials used in the present examples and comparative examples are shown together with the manufacturer, product name, and the like. Some of the test materials were synthesized by the present inventors.

・ Dicyclopentadiene type epoxy resin [Dainippon Ink Chemical Co., Ltd., trade name “EPICLON HP-7200H”]
・ Naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., trade name “EPICLON EXA-4700”]
Phosphorus-containing phenoxy resin [manufactured by Toto Kasei Co., Ltd., trade name “Phenotote ERF-001M30”]
・ Phenoxy resin [manufactured by Toto Kasei Co., Ltd., trade name “Phenototo YP-50EK35”]
-Liquid NBR [made by Nippon Zeon Co., Ltd., trade name “Nipol 1312”]
End-modified liquid NBR [manufactured by Nippon Zeon Co., Ltd., trade name “Nipol DN601”]
Magnesium hydroxide A [Kyowa Chemical Industry Co., Ltd., trade name “Kisuma 8”]
・ Magnesium hydroxide B
Magnesium hydroxide B was added with 100 g of the above magnesium hydroxide A in 1 L of distilled water, and 1 g of 3- (2-aminoethyl) aminopropyltrimethoxysilane was added with stirring and surface treatment was performed for 1 hour. It was obtained by drying at 100 ° C. and was subjected to silane coupling treatment.
Aluminum hydroxide For comparison, aluminum hydroxide was replaced with magnesium hydroxide A in the silane coupling treatment of magnesium hydroxide B. Aluminum hydroxide [manufactured by Sumitomo Chemical Co., Ltd., trade name “CL303”] This was synthesized in the same manner except that was used, and was subjected to silane coupling treatment.
・ Phenol type curing agent [Dainippon Ink Chemical Co., Ltd., trade name "TD-2090-60M"]
・ Glass cloth [manufactured by Nittobo Co., Ltd., trade name “WEA05E53SP”, thickness of about 55 μm]

(Production of epoxy resin composition and prepreg)
First, dicyclopentadiene-type epoxy resin, naphthalene-type epoxy resin, phosphorus-containing phenoxy resin, phenoxy resin, liquid NBR, terminal-modified liquid NBR, phenol-type curing so as to have the blending ratio shown in Tables 1 and 2 described later. By dissolving the agent in methyl ethyl ketone (MEK) and dimethylformamide (DMF), adding magnesium hydroxide A, magnesium hydroxide B and aluminum hydroxide, mixing and stirring, adding triphenylphosphine and stirring again, The impregnation liquid containing each epoxy resin composition according to Examples 1 to 14 and the impregnation liquid including each epoxy resin composition according to Comparative Examples 1 to 10 were prepared.

  Next, the glass cloth was immersed in each of the above impregnating solutions using an impregnation coater, and dried with hot air (temperature of about 120 ° C., 10 minutes) while controlling the coating thickness with a comma roll. Each prepreg (thickness: about 80 μm) of the B stage according to 14 and each prepreg (thickness: about 80 μm) of the B stage according to Comparative Examples 1 to 10 were produced.

(Evaluation methods)
Each composition and prepreg produced as described above were evaluated for each of the following items: linear expansion coefficient, resin flow, flame retardancy, peeling of inorganic flame retardant, lead-free solder heat resistance, and 180 ° peel strength. The evaluation method for each item is briefly described below.

(1. Linear thermal expansion coefficient)
Each prepreg in a semi-cured state (B stage) was cured in two stages, with a surface pressure of 8.5 MPa and a temperature of 120 ° C. × 15 minutes → 180 ° C. × 60 minutes. Subsequently, the linear expansion coefficient of each prepreg after curing was measured in accordance with JIS K7194 “Method for testing linear expansion coefficient by thermomechanical analysis of plastics”. At this time, a prismatic test piece (one side was 5 mm, thickness was 2 mm) was used as the test piece. The measurement temperature was in the range from 25 ° C. to 250 ° C., and the temperature elevation temperature was 5 ° C./min. The diameter of the detection rod of the test apparatus is φ3 mm.

  In this evaluation, the case where the linear expansion coefficient in the thickness direction of the test piece was 50 ppm / ° C. or less was determined to be acceptable (◯), and the case where it exceeded 50 ppm / ° C. was determined to be unacceptable (x).

(2. Resin flow)
A hole having a diameter of 6 mm was formed in each prepreg of the B stage, and the hole size (see FIG. 1) of the prepreg before curing was measured by a projector. Next, the test piece was sandwiched between two polyimide films (thickness 50 μm), and cured in two stages, with a surface pressure of 8.5 MPa and a temperature of 120 ° C. × 15 minutes → 180 ° C. × 60 minutes. Subsequently, the hole size (refer FIG. 1) of the prepreg after hardening was measured with the projector.

  From this result, the area change rate before and after curing is calculated using the following equation (1). If this area change rate is 5% or less, it is accepted (◯), and if it exceeds 5%, it is rejected ( X).

(3. Flame resistance)
Each prepreg of the B stage was cured in two stages, with a surface pressure of 8.5 MPa and a temperature of 120 ° C. × 15 minutes → 180 ° C. × 60 minutes. Next, the flame retardancy of each prepreg after curing was evaluated according to UL standard 94-V0. The case where UL94-V0 was satisfied was determined to be acceptable (◯), and the case where it was not satisfied was determined to be unacceptable (x).

(4. Removal of inorganic flame retardant)
Each prepreg of the B stage was bent at 90 °, and it was visually confirmed whether or not the inorganic flame retardant peeled off. The case where the inorganic flame retardant did not peel off was determined to be acceptable (O), and the case where the inorganic flame retardant occurred was determined to be unacceptable (X).

(5. Lead-free solder heat resistance)
Each laminated body laminated in the order of each prepreg / Cu foil of Cu foil / B stage was cured in two stages with a surface pressure of 8.5 MPa and a temperature of 120 ° C. × 15 minutes → 180 ° C. × 60 minutes. One side was 3 cm and the thickness was 230 μm). Next, each copper clad double-sided plate was floated in a solder bath at about 280 ° C. for about 20 seconds.

  The case where the surface of the copper-clad double-sided board did not bulge after about 20 seconds was determined to be acceptable (◯), and the case where it bulged was regarded as unacceptable (x).

(6. 180 ° peel strength)
Each prepreg of the B stage is sandwiched between two polyimide films (thickness 50 μm) and cured in two stages with a surface pressure of 8.5 MPa and a temperature of 120 ° C. × 15 minutes → 180 ° C. × 60 minutes. One side was 1 cm and thickness was 180 μm). Subsequently, the 180 ° peel strength was measured in accordance with JIS K6854-2 “Adhesive—Peeling peel strength test method—Part 2: 180 degree peel”. The speed at which the polyimide film was grasped and peeled was 20 mm / min.

  A specimen having a 180 ° peel strength of 8 N / cm or more was regarded as acceptable (◯), and a specimen less than 8 N / cm was regarded as unacceptable (x).

  Tables 1 and 2 below show the blending ratio and evaluation results of this composition.

  According to the said Table 1, 2, it turns out that the epoxy resin composition and prepreg which concern on a comparative example have a difficulty in either evaluation item.

  More specifically, Comparative Example 1 and Comparative Example 2 contain aluminum hydroxide that is inferior in heat resistance to magnesium hydroxide as an inorganic flame retardant, so the processing temperature of lead-free solder (about 280 ° C.) It can be seen that it does not have heat resistance that can withstand.

  Further, in Comparative Examples 3 and 4, since the phosphorus-containing phenoxy resin and phenoxy resin, which are modifiers, are less than the specified amount, magnesium hydroxide added in a large amount cannot be embedded sufficiently in the resin, It can be seen that the magnesium oxide peeled off.

  Moreover, since the comparative example 5 and the comparative example 6 have more phosphorus-containing phenoxy resin and phenoxy resin which are modifiers than a prescribed amount, it turns out that adhesiveness with a polyimide film deteriorated and 180 degree peel strength fell. .

  In Comparative Example 7 and Comparative Example 8, since the liquid NBR and terminal-modified liquid NBR that are the modifiers are less than the specified amount, the magnesium hydroxide added in a large amount cannot be embedded sufficiently in the resin. It can be seen that the magnesium oxide peeled off.

  Moreover, since the comparative example 9 and the comparative example 10 have more liquid NBR and terminal modified | denatured liquid NBR which are modifiers than a prescribed amount, it turns out that adhesiveness with a polyimide film deteriorated and 180 degree peel strength fell. .

  On the other hand, according to the epoxy resin composition and prepreg according to this example, all the evaluation items are satisfied. Therefore, the epoxy resin composition according to this example hardly causes resin flow during curing, and a prepreg using the epoxy resin composition is excellent in dimensional stability. In addition, the epoxy resin composition and the prepreg according to the present example have sufficient flame resistance, can suppress peeling of the inorganic flame retardant, and have heat resistance that can correspond to the processing temperature of lead-free solder. I was able to confirm.

It is the top view which showed typically the hole formed in each prepreg before and behind hardening.

Claims (2)

  Epoxy containing at least 20 to 50 parts by weight of phenoxy resin and / or acrylonitrile-butadiene rubber and 100 to 300 parts by weight of magnesium hydroxide with respect to 100 parts by weight of dicyclopentadiene type epoxy resin and / or naphthalene type epoxy resin Resin composition.   A prepreg obtained by impregnating or coating a base material with the epoxy resin composition according to claim 1 and drying and curing it.

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