JP2006008753A - Resin composition, prepreg and lamianted board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition capable of attaining its flame retardancy without using any halogen-containing compound and also capable of yielding a laminated board having sufficient soldering heat resistance and adhesiveness, and to provide a prepreg and such a laminated board each using the resin composition. <P>SOLUTION: The resin composition to be used for forming a sheet-like prepreg through impregnation in a base comprises an epoxy resin including a novolak-type epoxy resin, dicyandiamide, an aromatic amino compound having in the molecule an electron-attractive group and a flame retardant. The prepreg is obtained by impregnating a base with the resin composition. The laminated board is obtained by molding the prepreg(s). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition, a prepreg, and a laminate.

Thermosetting resins typified by epoxy resins and the like are widely used for electrical and electronic equipment parts because of their excellent characteristics. These thermosetting resins are often given flame retardancy in order to ensure safety against fire. Conventionally, halogen-containing compounds such as brominated epoxy resins have been generally used as a method for making these thermosetting resins flame retardant (see, for example, Patent Document 1).
However, halogen-containing compounds have a high degree of flame retardancy, but have the following problems. For example, aromatic bromine compounds can not only separate corrosive bromine and hydrogen bromide by pyrolysis, but also form highly toxic polybromodibenzofurans and polybromodibenzooxins when decomposed in the presence of oxygen. There is. Also, it is extremely difficult to dispose of obsolete waste containing bromine. For these reasons, flame retardants that replace bromine-containing flame retardants have been studied.

JP 2000-212249 A

  INDUSTRIAL APPLICABILITY The present invention provides a resin composition that can achieve flame retardancy without using a halogen-containing compound, and that can obtain a laminate having sufficient solder heat resistance and adhesion, and the same. A prepreg and a laminate are provided.

Such an object is achieved by the present invention described in the following (1) to (8).
(1) A resin composition used for impregnating a base material to form a sheet-like prepreg,
A resin composition comprising an epoxy resin containing a novolac-type epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant.
(2) The resin composition according to (1), wherein the content of the novolac epoxy resin is 60 to 90% by weight of the entire epoxy resin.
(3) The resin composition as described in said (1) or (2) whose said novolak-type epoxy resin is a cresol novolak-type epoxy resin.
(4) The aromatic amino compound having an electron withdrawing group in the molecule is 4,4′-diaminodiphenyl sulfone and / or 3,3′-diaminodiphenyl sulfone. The resin composition in any one.
(5) The resin composition according to any one of (1) to (4), wherein the flame retardant includes a phosphorus compound.
(6) The resin composition according to any one of (1) to (5), wherein the flame retardant is a phosphine oxide compound.
(7) A prepreg obtained by impregnating a base material with the resin composition according to any one of (1) to (6).
(8) A laminate obtained by molding one or more prepregs according to (7) above.

The present invention relates to an epoxy resin containing a novolac-type epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant, and a prepreg using the resin composition, Compared to conventional ones, the laminated plate can achieve flame retardancy without using a halogen-containing compound, and can exhibit sufficient solder heat resistance and adhesion.

The resin composition of the present invention is a resin composition used for impregnating a base material to form a sheet-like prepreg, and includes an epoxy resin containing a novolac-type epoxy resin, dicyandiamide, and an electron withdrawing in the molecule. It comprises an aromatic amino compound having a functional group and a flame retardant.
Moreover, the prepreg of the present invention is characterized in that a base material is impregnated with the above-mentioned resin composition.
Moreover, the laminated board of the present invention is formed by molding one or more of the above-described prepregs.
First, the resin composition of the present invention will be described.

The resin composition of the present invention includes a novolac type epoxy resin. Thereby, the flame retardance and solder heat resistance of the laminated board using the resin composition of this invention can be improved.
Although it does not specifically limit as a novolak-type epoxy resin, For example, a cresol novolak-type epoxy resin, a phenol novolak-type epoxy resin, a bisphenol A novolak-type epoxy resin etc. can be mentioned. Among these, a cresol novolac type epoxy resin is preferable. Thereby, a heat absorption can be reduced with a crosslink density increase, and a water absorption rate can be reduced.

  Although content of the said novolak-type epoxy resin is not specifically limited, 60 to 90 weight% of the whole epoxy resin is preferable, and 65 to 75 weight% is especially preferable. If the content of the novolak type epoxy resin is less than the lower limit, the effect of improving the solder heat resistance may be reduced, and if the content exceeds the upper limit, the effect of reducing the water absorption rate may be reduced.

  In addition, in the resin composition of this invention, although it does not specifically limit as epoxy resins other than the said novolak-type epoxy resin, For example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, etc. can be used.

  The resin composition of the present invention contains dicyandiamide. Thereby, adhesiveness can be improved, maintaining heat resistance.

  When dicyandiamide is used as a curing agent for an epoxy resin, the glass transition point of the cured epoxy resin is increased. Further, since nitrogen atoms are contained in dicyandiamide, adhesion with a conductive circuit metal foil such as a copper foil is improved.

  However, dicyandiamide has low solubility in epoxy resins, particularly novolak-type epoxy resins. For this reason, when dicyandiamide is added in an amount necessary to sufficiently cure the novolac epoxy resin, dicyandiamide is precipitated in the resin composition, and unreacted dicyandiamide remains in the laminate, resulting in poor heat resistance. There is a problem to do. Further, the amount of dicyandiamide that can be dissolved in the novolac type epoxy resin has a problem that the curing is insufficient and the heat resistance is deteriorated.

On the other hand, the resin composition of the present invention is characterized by using an aromatic amino compound having an electron withdrawing group in the molecule together with dicyandiamide. Thereby, adhesiveness can be provided, without reducing heat resistance.
In the resin composition of the present invention, since an aromatic amino compound having an electron withdrawing group in the molecule is used together with dicyandiamide, the dicyandiamide is an epoxy resin containing a novolac type epoxy resin (hereinafter simply referred to as “epoxy resin”). A sufficient amount can be used. Thereby, the heat resistant fall by unreacted dicyandiamide depositing can be prevented.
Moreover, since the aromatic amino compound which has an electron withdrawing group in a molecule | numerator can advance hardening reaction of an epoxy resin by the amino group, it can provide sufficient heat resistance.
Furthermore, the aromatic amino compound having an electron withdrawing group in the molecule has a feature that the viscosity of the resin composition is difficult to increase during the resin curing process because the curing reaction rate for the epoxy resin is slower than that of dicyandiamide. . Thereby, the compounded dicyandiamide can be efficiently reacted with the epoxy resin without substantially reducing the solubility of dicyandiamide in the epoxy resin.
As described above, the resin composition of the present invention has not only the single effect each of the dicyandiamide and the aromatic amino compound having an electron withdrawing group in the molecule, but also the above-mentioned synergistic effect by using both in combination. It also has. Even when a novolak epoxy resin having low solubility of dicyandiamide is used, high adhesion and heat resistance can be imparted to the laminate.

The content of dicyandiamide is not particularly limited, but is preferably 2.0 to 4.5 parts by weight, particularly preferably 2.5 to 4.0 parts by weight with respect to 100 parts by weight of the epoxy resin.
If the content is less than the above lower limit value, the adhesion may be lowered, and if it exceeds the upper limit value, dicyandiamide may be precipitated and the heat resistance may be lowered.

The aromatic amino compound having an electron withdrawing group in the molecule is not particularly limited. For example, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone 4,4′-diaminostilbene-2,2′-disulfonic acid, 3,3′-dimethyl-4,4′-diaminobiphenyl-6,6′-disulfonic acid, o-toluidine disulfonic acid, 4,4 ′ -Diaminobenzophenone, 4,4'-diamino-3,3'-dicyanodiphenylmethane and the like.
Among these, 4,4′-diaminodiphenylsulfone and 3,3′-diaminodiphenylsulfone are preferable because they have good solubility in epoxy resins and do not inhibit the curing of dicyandiamide.
Here, examples of the electron withdrawing group in the aromatic amino compound having an electron withdrawing group in the molecule include a sulfonyl group, a carbonyl group, and a cyano group.

Although content of the aromatic amino compound which has an electron withdrawing group in the said molecule | numerator is not specifically limited, 2-12 weight part is preferable with respect to 100 weight part of epoxy resins, and 5-10 weight part is especially preferable.
If the content is less than the above lower limit, the epoxy resin may not be sufficiently cured, and the heat resistance of the laminate may be reduced. On the other hand, if the above upper limit is exceeded, the amount of aromatic amino compound that cannot participate in the curing reaction increases, so that the heat resistance may similarly decrease.

The resin composition of the present invention contains a flame retardant.
As the flame retardant, those having no halogen in the molecule can be suitably used, and the kind thereof is not particularly limited. For example, phosphoric flame retardant such as phosphate ester, melamine phosphate and phosphine oxide, hydroxylation Examples thereof include inorganic flame retardants such as magnesium and aluminum hydroxide, and nitrogen flame retardants such as melamine and melamine cyanurate.
Among these, phosphorus flame retardants are preferable. Thereby, it can be made flame-retardant without using a halogen compound. As the phosphorus flame retardant, a phosphine oxide compound is most preferable from the viewpoint of chemical resistance.

  Although content of the said flame retardant is not specifically limited, 5 to 30 weight% of the whole resin composition is preferable, and 10 to 20 weight% is especially preferable. If the content is less than the lower limit, the effect of improving flame retardancy may be reduced, and if the content exceeds the upper limit, the adhesion with the metal foil may be reduced.

  The resin composition of the present invention contains an epoxy resin containing the above-described novolak epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant as essential components. Other resins, curing accelerators such as imidazole compounds, coupling agents, and other components may be added without departing from the object of the invention.

Next, the prepreg will be described.
The prepreg of the present invention is obtained by impregnating a base material with the above resin composition. Thereby, the prepreg excellent in various characteristics, such as heat resistance, can be obtained.
Examples of the base material used in the prepreg of the present invention include glass fiber base materials such as glass fiber cloth and glass non-woven cloth, inorganic fiber base materials such as fiber cloth and non-fiber cloth containing inorganic compounds other than glass, and aromatic polyamide resins. And organic fiber base materials composed of organic fibers such as polyamide resin, aromatic polyester resin, polyester resin, polyimide resin, and fluororesin. Among these base materials, glass fiber base materials represented by glass woven fabric are preferable in terms of strength and water absorption.

  Examples of the method of impregnating the substrate with the resin composition obtained in the present invention include, for example, a method in which a resin varnish is prepared by dissolving the resin composition in a solvent, and the substrate is immersed in the resin varnish. The method of apply | coating a varnish to a base material, the method of spraying a resin varnish on a base material with a spray apparatus, etc. are mentioned. Among these, the method of immersing the base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to a base material can be improved. In addition, when a base material is immersed in a resin varnish, a normal impregnation coating device can be used.

The solvent used in the resin varnish desirably exhibits good solubility in the resin composition of the present invention, but a poor solvent may be used within a range that does not adversely affect the resin varnish. Examples of the solvent exhibiting good solubility include dimethylformamide and dimethylacetamide.
The solid content in the resin varnish is not particularly limited, but the solid content of the resin composition is preferably 40 to 80% by weight, and particularly preferably 50 to 65% by weight. Thereby, the impregnation property to the base material of the resin varnish can further be improved.
A prepreg can be obtained by impregnating the base material with the resin composition and drying at a predetermined temperature, for example, 80 to 200 ° C.

Next, a laminated board is demonstrated.
The laminate of the present invention is formed by molding at least one prepreg described above. Thereby, the laminated board which has the outstanding heat resistance and favorable flame retardance can be obtained.
In the case of a single prepreg, a metal foil or film is stacked on both upper and lower surfaces or one surface.
Two or more prepregs can be laminated. When two or more prepregs are laminated, a metal foil or film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepreg.
Next, a laminate can be obtained by heating and pressurizing a laminate of a prepreg and a metal foil.
The heating temperature is not particularly limited, but is preferably 120 to 220 ° C, particularly preferably 150 to 200 ° C.
Moreover, the pressure to pressurize is not particularly limited, but is preferably 2 to 5 MPa, and particularly preferably 2.5 to 4 MPa.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

Example 1
(1) Preparation of resin varnish Cresol novolac type epoxy resin (epoxy equivalent 210, Dainippon Ink & Chemicals N
-690) 72.6 parts by weight, bisphenol A type epoxy resin (epoxy equivalent 190, 850 manufactured by Dainippon Ink & Chemicals, Inc.) 27.4 parts by weight, dicyandiamide 3.6 parts by weight, 4,4′-diaminodiphenylsulfone 5 Dimethylformamide was added to 0.8 parts by weight, 13.3 parts by weight of triphenylphosphine oxide, and 0.1 parts by weight of 2-methylimidazole, and a resin varnish was prepared so as to have a nonvolatile concentration of 55% by weight.

(2) Production of prepreg Using the above resin varnish, 100 parts by weight of glass fiber cloth (thickness 0.18 mm, manufactured by Nitto Boseki Co., Ltd.) was impregnated with 80 parts by weight of the resin varnish as a solid content. A prepreg having a resin content of 44.4% by weight was prepared by drying in a drying furnace at 150 ° C. for 5 minutes.

(3) Manufacture of laminated board Six sheets of the above prepreg are stacked, and an electrolytic copper foil with a thickness of 35 μm is stacked on the top and bottom, and the pressure is 4 MPa, the temperature is 200 ° C. for 120 minutes, and the temperature is 220 ° C. for 60 minutes. A double-sided copper clad laminate having a thickness of 1.2 mm was obtained.

(Example 2)
A resin varnish was prepared in the same manner as in Example 1 except that the blending amount of dicyandiamide was 2.9 parts by weight, and the blending amount of 4,4′-diaminodiphenylsulfone was 9.5 parts by weight. Got.

Example 3
A resin varnish was prepared in the same manner as in Example 1 except that 3,3′-diaminodiphenylsulfone was used as an aromatic amino compound having an electron withdrawing group in the molecule, and a prepreg and a laminate were obtained.

Example 4
The amount of dicyandiamide used is 70.6 parts by weight of phenol novolac epoxy resin (epoxy equivalent 190, N-770 manufactured by Dainippon Ink & Chemicals, Inc.) and 29.4 parts by weight of bisphenol A epoxy resin as novolak epoxy resin. A resin varnish was prepared in the same manner as in Example 1, except that 3.8 parts by weight and 4,4′-diaminodiphenylsulfone was used in an amount of 6.2 parts by weight to obtain a prepreg and a laminate.

(Comparative Example 1)
A resin varnish was prepared in the same manner as in Example 1 except that an aromatic amino compound having an electron withdrawing group in the molecule was not used, only dicyandiamide was used as a curing agent, and the blending amounts shown in Table 1 were used. A laminate was obtained.

(Comparative Example 2)
The same as in Example 1 except that the aromatic amino compound having an electron withdrawing group in the molecule is not used, and 4,4′-diaminodiphenylmethane having no electron withdrawing group is used and the blending amount is as shown in Table 1. A resin varnish was prepared to obtain a prepreg and a laminate.

  The following evaluation was performed about the laminated board obtained by each Example and the comparative example. Each evaluation is shown below together with the evaluation method. The obtained results are shown in Table 1.

Notes to the table Raw material (1) Cresol novolac type epoxy resin (epoxy equivalent 210, trade name: Dainippon Ink & Chemicals N-690)
(2) Phenol novolac type epoxy resin (epoxy equivalent 190, trade name: N-770 manufactured by Dainippon Ink & Chemicals, Inc.)
(3) Bisphenol A type epoxy resin (epoxy equivalent 190, trade name: 850 manufactured by Dainippon Ink & Chemicals, Inc.)

2. Evaluation methods

  The following evaluation was performed about the laminated board obtained by each Example and the comparative example. Each evaluation is shown below together with the evaluation method. The obtained results are shown in Table 1.

(1) Flame retardancy Flame retardancy was evaluated according to the UL vertical method.

(2) Solder heat resistance The solder heat resistance was measured in accordance with JIS C 6481. In the measurement, after performing a moisture absorption treatment for 2 hours after boiling, it was immersed in a solder bath at 260 ° C. for 120 seconds and then examined for abnormal appearance.

(3) Water absorption The water absorption was measured according to JIS C 6481.

(4) Peel strength The peel strength was measured in accordance with JIS C 6481.

(5) Glass transition temperature The glass transition temperature was determined from the peak temperature of tan δ by a viscoelastic method.

As is apparent from the table, Examples 1 to 4 are books containing an epoxy resin containing a novolac type epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant. It is a laminated board using the resin composition of the invention, and was excellent in flame retardancy, solder heat resistance and adhesion.
On the other hand, Comparative Example 1 used only dicyandiamide as the curing agent, but the solder heat resistance and adhesion were lowered. In Comparative Example 2, an aromatic amino compound having no electron withdrawing group was used together with dicyandiamide, but the epoxy resin was not sufficiently cured and the solder heat resistance was lowered.

The present invention relates to an epoxy resin containing a novolac-type epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant, and a prepreg using the resin composition, Compared to conventional ones, the laminated plate can achieve flame retardancy without using a halogen-containing compound, and can exhibit sufficient solder heat resistance and adhesion.
Therefore, the present invention can be suitably used for printed wiring boards that require high flame retardancy, heat resistance, and adhesion.

Claims (8)

A resin composition used for impregnating a base material to form a sheet-like prepreg,
A resin composition comprising an epoxy resin containing a novolac-type epoxy resin, dicyandiamide, an aromatic amino compound having an electron withdrawing group in the molecule, and a flame retardant. 2. The resin composition according to claim 1, wherein the content of the novolac type epoxy resin is 60 to 90% by weight of the whole epoxy resin. The resin composition according to claim 1 or 2, wherein the novolac type epoxy resin is a cresol novolac type epoxy resin. The resin according to any one of claims 1 to 3, wherein the aromatic amino compound having an electron withdrawing group in the molecule is 4,4'-diaminodiphenyl sulfone and / or 3,3'-diaminodiphenyl sulfone. Composition. The resin composition according to claim 1, wherein the flame retardant contains a phosphorus compound. The resin composition according to claim 1, wherein the flame retardant is a phosphine oxide compound. A prepreg obtained by impregnating a base material with the resin composition according to any one of claims 1 to 6. A laminate obtained by molding one or more prepregs according to claim 7.