JPH02184432A - Laminate with ultraviolet ray-absorbing property for electrical use - Google Patents

Abstract

PURPOSE:To cause the manufacture of a laminate to be easy, while effective ultraviolet ray-absorbing faculty is obtained by compounding the specified amount of the photoinitiator for radical photopolymerization activating cured thermosetting resin by radiating ultraviolet rays with the laminate. CONSTITUTION:A laminate is composed of the base impregnated with thermosetting resin and metallic foil, and with said materials, 0.2-6.0wt.% of photoinitiator for radical photopolymerization activating cured thermosetting resin by radiating ultraviolet rays is compounded. As the photoinitiator for radical photopolymerization, and initiator of photocleavage type generating radical in the cleavage of itself by radiating light and the onium salt of cation group are preferably used. For instance, halogen substituted acetophenone, acetophenone group, benzoin group, substituted alpha-aminoketone, thioxanthon derivative of hydrogen- obstraction type or thiol salt etc., is used. Photoinitiator may be uniformly compounded with the whole of thermosetting resin, and it may be also compounded with a part of a prepreg.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves forming a UV-sensitive resin film on the surface of a laminate after forming a printed wiring network that has an ultraviolet absorption ability, and forming a UV-sensitive resin film in a specific pattern. After selectively forming a UV-sensitive resin film on the front and back sides of the laminate, when forming a printed wiring network by electroless plating, the side opposite to the irradiated side (back side) This relates to metal foil-clad laminates and laminates that solve the problem of exposing undesired parts of the ultraviolet-sensitive resin film on the irradiated surface, making it difficult to form accurate patterns, and preventing deterioration of heat resistance, hue, etc. It is something without.

[Conventional technology and its problems]

Conventionally, in the production of laminates made by laminating and molding prepreg made by impregnating and drying glass non-woven fabric or glass woven fabric with epoxy resin, and metal foil-clad laminates in which prepreg and metal foil are laminated and molded, ultraviolet rays cannot be transmitted. In order to prevent this, there is a method of adding inorganic fillers and dyes. This method has the disadvantage that the cured resin-impregnated base material of the obtained laminate becomes opaque or colored. In addition, there are various methods of blending ultraviolet absorbers, optical brighteners, etc. into epoxy resins, such as in JP-A No. 62-132390, but the ultraviolet absorbers may color the resin, or heat the resin surface of the laminate. The disadvantage is that the epoxy resin may change color, and the glass transition temperature of the epoxy resin usually decreases.

[Means to solve the problem]

The present inventor has completed the present invention as a result of intensive study on a method that solves the above-mentioned problems, provides efficient ultraviolet absorption ability, and facilitates the production of a laminate.

That is, the present invention provides an electrical laminate comprising a substrate impregnated with a cured thermosetting resin or a substrate impregnated with the resin and a metal foil, in which the cured thermosetting resin is activated by radical light irradiated with ultraviolet rays. The photoinitiator for polymerization is 0.2 to 6.
This is an electrical laminate having ultraviolet absorbing ability, characterized in that it contains 0% by weight.

Photosensitive films such as photopolymerized protective paints formed on laminates are
It contains a photoinitiator as a component, which absorbs light and generates radicals and cations to harden the coating film. Therefore, by mixing a photoinitiator similar to the photoinitiator incorporated in the photosensitive film into the matrix resin of the laminate, it is possible to effectively prevent undesired areas from being exposed to light. The photoinitiator in the photosensitive film is consumed with light irradiation and loses its light absorption ability, but the photoinitiator blended into the cured resin is not consumed even with light irradiation, but rather increases in the rate of curing. The light absorption ability is improved by the interaction with other compounds in the resin. Therefore, it is possible to create a laminate that does not transmit light even when exposed to ultraviolet rays for a long period of time.

The configuration of the present invention will be explained below.

The base material of the thermosetting resin-impregnated base material of the present invention is not particularly limited as long as it is used in various known electrical laminates, but it is usually a glass nonwoven fabric or a glass woven fabric. The most effective are non-woven fabrics or woven fabrics made of glass fibers and other fibers, especially those that are nearly transparent, such as laminates using glass non-woven fabrics or woven fabrics, and there are no particular restrictions on the thickness. Usually 0.1 to 0.40 mm is suitable.

Further, the thermosetting resin of the present invention is not particularly limited as long as it is used in various known electrical laminates, but epoxy resins are particularly effective, and bisphenol A type Epoxy resin, phenol novolac type epoxy resin, Talesol novolac type epoxy resin, brominated bisphenol A type epoxy resin, brominated phenol novolac type epoxy resin, other polyfunctional epoxy resins; these epoxy resins include polyetherimide, Heat-resistant engineering plastics such as polyphenylene ether, known modifying resins such as saturated or unsaturated polyester resins, phenols such as dicyandiamide, diaminodiphenylmethane, and phenol novolak resins, known curing agents such as acid anhydrides, etc.
-Imidazoles such as methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimitasole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, and amines such as benzyldimethylamine curing catalysts such as
Examples include those containing inorganic fillers, organic fillers, flame retardants, pigments, dyes, etc.

The photoinitiator for radical photopolymerization that is activated by UV irradiation and is blended into the thermosetting resin of the present invention is a composition that photopolymerizes a compound having an unsaturated carbon-carbon double bond such as acrylate by UV irradiation. More suitable are photocleavable initiators and cationic onium salts, which are compounds commonly used in , and which themselves cleave to produce radicals upon irradiation with light. Such photoinitiators include halogen-substituted acetophenones such as p-phenoxy-1,1,1-)lichloroacetophenone, p-t-butyl-1,1,1-)lichloroacetophenone, and 1-chloroacetophenone. Dialkoxyacetophenones such as 2,2-dimethoxy-2-phenylacetophenone and 2,2-jethoxyacetophenone; 1-phenyl 2-hydroxy-2-methyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone Acetophenones such as α-hydroxyacetophenone; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether; benzyl-2-o-
α-acyl oxime esters such as benzoyl oxime; benzyl dialkyl ketals such as benzyl dimethyl ketal; ; acylphosphine oxides such as 2.4.6-drimethylbenzoyldiphenylphosphine oxide:; next page formula (1 ); Hydrogen-abstracting Michler ketones such as bis(P-dimethylamino)benzophenone; Hydrogen-abstracting dioxanzone derivatives such as 2-chlorothioxacin; Hydrogen-abstracting thiolenes:; Examples include cationic photopolymerization initiators such as the phosphonium salt of formula (2).

Formula (1); Formula (2); The blending amount of the photoinitiator is 0.2 to 6% relative to the total solid content of the thermosetting resin.
It is within the range of weight %, and may be blended uniformly into the entire thermosetting resin or blended into a portion of the prepreg. The blending amount is 0.
If it is less than 2% by weight, the ultraviolet absorbing ability will be insufficient, and if it is more than 6.0% by weight, various properties of the electrical laminate will deteriorate, which is not preferable.

The above components are used to produce the prepreg of the present invention, one or more sheets of the prepreg are used, and are placed in combination with a normal prepreg as appropriate at the center, both outer sides, etc. of a resin-impregnated base material, and a metal foil ( (e.g., copper, aluminum, iron, etc.), a printed wiring board for the inner layer, a single-sided copper-clad laminate for the outer layer, etc., using normal lamination molding methods such as multi-stage press, multi-stage vacuum press, continuous molding, autoclave molding, etc. , temperature 100~200℃, pressure 2~100 kg/c
The electrical laminate of the present invention is manufactured by lamination molding under normal lamination molding conditions for a time of 0.03 to 3 hours.

〔Example〕

The present invention will be explained below with reference to Examples. Note that "parts" and "%" in Examples are based on weight unless otherwise specified.

Example 1 Brominated bisphenol A type epoxy resin (trade name: Epicoat 1045, Br content 18-20%, epoxy equivalent 450-500, manufactured by Yuka Shell Epoxy ■) 100
3.5 parts of dicyandiamide and 0.2 parts of 2-methylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and N,N-dimethylformamide to a thickness of 0.18 mm.
A prepreg with a resin content of 45% (hereinafter referred to as PP-1) was produced by impregnating a plain weave glass woven fabric with the resin and drying it at 160° C. for 6 minutes.

2,2-dimethoxy 2-phenylacetophenone (trade name: Irgacure) was added to the above epoxy resin varnish.
A prepreg with a resin content of 45% (hereinafter referred to as PP-2) was produced in exactly the same manner except that 651 (manufactured by Ciba Geigy) was added in an amount of 2.0% of the resin solid content.

A total of 8 sheets of PP (or PP-2) were stacked, electrolytic copper foil with a thickness of 35ρ was stacked on both sides, and the temperature was 170℃, 30kg/cnf.
A double-sided copper-clad laminate with a thickness of 1.6 mm was produced by lamination molding for 2 hours.

After etching the obtained copper-clad laminate to remove the copper foil on both sides, the laminate was heated with a high-pressure mercury lamp (wavelength 300-4
00n+n, 1kW, @ made by Ushio L-tic,
The light transmittance was measured with a distance of 20 cm from the old type. The light intensity on the surface of the laminate is 10 mW/cJ.
As a light receiver, an IVD-405PD manufactured by Ushio Electric, which receives light at wavelengths of 330 to 490 parts m, was used.

For comparison, instead of Irgacure 651, 2-
(2-hydroxy-3,5-di-t-amylphenyl)
Prepreg (hereinafter referred to as PP) using benzotriazole
-3) or optical brightener (trade name: UBITEX)
Prepreg using OB (manufactured by Ciba Geigy) (
The procedure was the same as above except that PP-4 (hereinafter referred to as PP-4) was used.

These results are shown in Table 1.

Example 2 In Example 1, Irgacure 651 was replaced with 1-hydroxycyclohexylphenyl ketone (trade name: Irgacure 184, manufactured by Ciba Geigy: molecular weight 204, m, p, 44-48°C, hereinafter referred to as Ir1).
Prepreg (hereinafter referred to as PP-
5) was used in combination with PP-1 of Example 1 as shown in Table 2 to produce a laminate, and after removing the copper foil on both sides by etching, After applying photoresist (DPR-105, manufactured by Asahi Kagaku Kenkyusho) on both sides and drying at 90°C for 40 minutes, a negative film was placed on one side and exposed to ultraviolet light using a high-pressure mercury lamp at a light intensity of 800 mJ/crJ. was irradiated, and the photosensitivity of the photoresist on the back surface and the light transmittance at the time of 500 mJ/cnt irradiation were measured. The results are shown in Table 2.

Example 3 In Example 1, Irgacure 651 was replaced with 12.0% of Irgacure 651 and a cationic photoinitiator (onium salt type, trade name: Irgacure
261, manufactured by Ciba Geigy: molecular weight 386. m, p,
A prepreg (hereinafter referred to as PI'-6) was produced in the same manner except that 0.5% (86°C) was used, and this PP-62
A laminate with a thickness of 0.4 mm was manufactured using PP-12 sheets and PP-12 sheets.

After etching the obtained copper-clad laminate to remove the copper foil on both sides, the laminate was heated with a metal halide lamp (wavelength 38
0-420 nm, 1 kW, 0% manufactured by Ushioni Chikku, GL type) with a light intensity of 24 mW/cJ,
Total 700 mJ/cn! irradiated with light.

The light transmittance measured at this time was 3% in the case of the present invention using 2 PP-6 sheets, and 22% in the comparison using 2 PP-12 sheets. Further, when a liquid resist (PSR-1000, manufactured by Taiyo Ink ■) was applied to both sides of a PP-6 laminate and dried, an exposure test was conducted, and the resist on the back side was found to have no photosensitivity.

[Operation and effects of the invention]

As described above, the electrical laminate of the present invention uses the same amount of photoinitiator as the ultraviolet absorber, and not only exhibits the same ultraviolet absorption ability from the beginning, but also as the amount of ultraviolet irradiation increases. Therefore, the performance of blocking ultraviolet rays is improved.

As a result, it exhibits a completely new property not found in ultraviolet absorbers, in that there is no risk of exposure even during long-term exposure with a large amount of light for exposing the photoresist.

Further, since the obtained printed wiring board usually undergoes a process such as heating, no deterioration is observed in hue.

As described above, it is understood that the electrical laminate of the present invention is extremely excellent in practical terms.

Procedural amendment (voluntary) February Z″2-day, 1999

Claims (1)

[Claims] In an electrical laminate comprising a cured thermosetting resin-impregnated base material or the resin-impregnated base material and metal foil, the cured thermosetting resin contains a photoinitiator for radical photopolymerization that is activated by ultraviolet irradiation. An electrical laminate having ultraviolet absorbing ability, characterized in that it contains 0.2 to 6.0% by weight.