JPH0412843A - Metal foil clad laminated sheet - Google Patents

Abstract

PURPOSE:To reduce hygroscopicity and the lowering of electric characteristics and to impart excellent mechanical strength and heat resistance by coating the surface of the cellulose fiber used in a printed circuit board or the like and constituting a base material with a melamine type resin. CONSTITUTION:In a metal foil clad laminated sheet consisting of an allyl ester resin, a base material based on a cellulose fiber and a metal foil, the surface of the cellulose fiber constituting the base material is substantially coated with a melamine type resin. This cellulose fiber coated with the melamine type resin is impregnated with the allyl ester resin and a plurality of impregnated cellulose fiber layers are laminated. In the metal foil clad laminated sheet, a metal foil having an adhesive preliminarily applied to the single surface or both surfaces thereof or not coated with the adhesive is superposed on the cellulose fiber laminate and the whole is heated, cured and molded under pressure or under a pressure free condition to prepare the laminated sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal-clad laminate for forming printed circuits and the like used in electrical equipment, electronic equipment, communication equipment, and the like.

The metal foil-clad laminate used in the present invention refers to a metal foil-clad laminate used, for example, as a substrate for various electronic components or a printed circuit board, and its shape is 05 to 5 mm in thickness. A plate-like object.

[Prior Art] Various types of metal foil-clad laminates have been put into practical use for use as laminates for printed circuits.

For example, in the case of cellulose fiber-based materials, it is common to construct a laminate of phenolic resin and paper, or unsaturated polyester resin and paper, and laminate metal foil on one or both sides of this laminate. Regarding metal-clad laminates composed of allyl ester resin and cellulose fibers, for example, Japanese Patent Application No. 1-255038
proposed in No.

[Problems to be Solved by the Invention] When manufacturing a metal foil laminate made of allyl ester resin and cellulose fibers, if the cellulose fibers are used as they are, the resulting laminate will have high hygroscopicity or high hygroscopicity and will not generate electricity due to moisture absorption. There are problems such as deterioration of physical properties and unstable mechanical strength and heat resistance due to insufficient bonding strength between the cured allyl ester resin and cellulose fibers.

Therefore, it is an object of the present invention to solve the above-mentioned drawbacks of metal foil-clad laminates made of allyl ester resin and cellulose fibers.

[Means for solving the problem] In order to achieve the above object, in a metal foil-clad laminate made of an allyl ester resin, a base material mainly composed of cellulose fibers, and metal foil, the cellulose fibers constituting the base material are As a result of intensive research into surface modification, the present invention was completed.

In a metal foil-clad laminate consisting of a base material mainly composed of allyl ester resin, cellulose fibers, and metal foil, the surface of the cellulose fibers constituting the base material is substantially covered with melamine resin. This is the gist of the invention for a metal foil clad laminate.

The melamine resin in the present invention refers to a suspension of methylol melamine resin, alkyl alcohol-modified methylol melamine resin, hydroxyethyl methacrylate-modified methylol melamine resin, etc., and these resins may be used alone or in combination of two or more. Can be used in combination.

Alkyl alcohol-modified methylol melamine resins and hydroquine ethyl methacrylate-modified methylol melamine resins are particularly preferred because they have good storage stability. In addition to lower alcohols such as methyl alcohol, propyl alcohol, and butyl alcohol, the alkyl alcohols used to obtain the alkyl alcohol-modified methylol melamine resin include higher alcohols made from natural oils and fats such as lauryl alcohol and oleyl alfur, and synthetic higher alcohols. or used.

In addition, modification here refers to reacting a modified compound such as alkyl alcohol or ethyl methacrylate together with melamine and formaldehyde when producing melamine resin, or when coating cellulose fiber with unmodified resin. It means to add and mix with melamine resin.

The general method for coating cellulose fibers is to impregnate them using a dipping bath, roll coater, spray, etc., and then dry them with hot air, but this is not the only method.

The amount of adhesion to cellulose fiber is 5 per 100 parts by weight of fiber.
The amount is preferably 8 to 25 parts by weight, preferably 8 to 25 parts by weight. If the amount is less than 5 parts by weight, the electrical properties of the resulting laminate will deteriorate significantly after absorbing moisture, and if it exceeds 30 parts by weight, it will become stiff and difficult to handle after drying, and its mechanical strength and heat resistance will deteriorate. .

The allyl ester resin as used in the present invention refers to a resin having an allyl ester group at the end of a saturated polyester composed of a saturated polybasic acid and a saturated polyhydric alcohol.

Examples of saturated polybasic acids include dibasic acids such as orthophthalic acid, orthophthalic acid m hydrate, isophthalic acid, phthalic acids such as terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, and methylenotomethylene. Hydrophthalic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, and their acid anhydrides; aliphatic dibasic acids such as malonic acid, succinic acid, glutaric acid, and anopic acid; tetrabromophthalic acid; acid, tetrachlorophthalic acid,
Examples include halogenated dibasic acids such as chlorendic acid and acid anhydrides thereof. Examples of trifunctional or higher-functional polybasic acids include trimellitic acid, pyromellitic acid, and acid anhydrides thereof. These can be used alone or in combination.

Saturated polyhydric alcohols include ethylene glycol, 1
, 2-propylene glycol, 1.4 butanediol,
1.6-hexanediol, neopentyl glycol,
1.4-In addition to dihydric alcohols containing aliphatic, alicyclic or aromatic compounds such as ncrohenoxane dimetatool and baraxylene glycol, general formula HO (CHRCH, O). H
(R is H or C, , H, , m is an integer of 1 to 5, n
is an integer from 2 to 10),
Examples include dihydric alcohols obtained by addition reaction of alkylene oxide such as propylene oxide.

Examples of trihydric or higher polyhydric alcohols include aliphatic trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric or higher alcohols such as pentaerythritol and sorbitol.

In addition, by using an aliphatic, alicyclic or aromatic halogenated polyhydric alcohol containing a halogen atom, such as dibrome neopentyl glycol or an ethylene oxide or propylene oxide adduct of tetrabromo bisphenol A, Allyl ester resins can be obtained and these can be used alone or in combination.

The method for producing allyl ester resins is already known and is described, for example, in Japanese Patent Application No. 63-262217.

For example, allyl ester resin is produced by charging soaryl ester of a saturated dibasic acid such as allyl terephthalate and a saturated polyhydric alcohol together with a transesterification catalyst into a reactor and reacting while distilling off allyl alcohol.

As an industrially more effective method, instead of allyl terephthalate, a sialyl ester of a saturated dibasic acid such as dimethyl terephthalate is charged into a reactor together with allyl alcohol, a polyhydric alcohol, and a transesterification catalyst, and cleavage of methanol, etc. It can be obtained by reacting while distilling off the alcohol. Further, depending on the reaction performance, a polymerization inhibitor such as hydroquinone may be coexisting in the reaction solution. In this way, an allyl ester resin having an allyl ester group at the end of a saturated polyester can be produced.

The allyl ester resin used in the present invention may be one type or a mixture of two or more of the various allyl ester resins described above.

Further, it is also possible to use an additive type flame retardant together with the allyl ester resin in the present invention. Additive flame retardants include tolumethyl phosphate, toluethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, cresyl diphenyl phosphate. , phosphorus-based flame retardants such as triphenyl phosphite, chlorinated paraffin, chlorinated polyethylene, decabromumphenyl ether, tetrabrom diphenyl ether, tetrabromo ethane, tetrabromo butane, 1
, 2. Halokene flame retardants such as 3-1-ribromopropane, tetrabromoenzene, and tetrabromobisphenol A, antimony compounds such as antimony trioxide and antimony pentoxide, zinc borate, aluminum hydroxide, and magnesium hydroxide. etc. can be mentioned.

In the present invention, in addition to the allyl ester tree B'F+ and the halokene-containing allyl ester resin, crosslinkable monomers capable of lanocal polymerization may be used.

As this crosslinking monomer, any known ones can be used, such as noaryl orthophthalate,
77' lylphthalates such as 7allyl isophthalate and /allyl terephthalate; substituted styrenes such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, fromustyrene, and divinylbenzene; methyl (meth)acrylate; , (meth)acrylate, butyl (meth)acrylate, 2-ethylhequinyl (meth)acrylate, lauryl (meth)acrylate, benzyl acrylate, phenyl (meth)bromination
Acrylic acid or methacrylic esters such as acrylic esters, ethylene glycol di(meth)acrylate, 1,4 butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, diacrylated isone anurate , pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin di(meth)acrylate, inopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate; ) acrylate, polyether (meth)acrylate, epichlorohydrin-modified bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, polyethylene glycol di(meth)acrylate,
Vinyl polyfunctional acrylic acids or methacrylic acid esters such as polybrobylene glycol di(meth)acrylate are included.

There is no problem in using two or more types of these crosslinking monomers in combination depending on the purpose. When a crosslinking monomer is added to allyl ester resin,
The viscosity of the allyl ester resin, which is a solid or viscous liquid, can be lowered, and the manufacturing process of the laminate can be simplified without going through a prepreg state using a solvent or the like.

The allyl ester resin in the present invention can be cured using a general-purpose organic peroxide, and may be used together with the organic peroxide or alone, such as a polymerization initiator that is sensitive to light, a polymerization initiator that is sensitive to radiation, or an electron beam. Known polymerization initiators can also be used.

Examples of organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, 1,1-bis(t-butylperoxy)3,3.5-h-limethylcyclohexane, n-
Peroxy ketals such as butyl-4,4-bis(1-butylperoxy)valerate, hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, di- /alkyl peroxides such as t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2゜5-no(t-butylperoxy)hexane, diane ruber such as lauroyl peroxide, hensyl peroxide, etc. oxides, such as cy-1so-probilveroxycarbonate, bis(4-t-)(tyl/lylohexyl)carbonate, etc. Examples thereof include peroxy/dicarbonates, t-butylperoquine piperate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, and other peroquine esters. These may be used alone or in combination of two or more depending on the type of resin and curing conditions.

In the present invention, fillers, reinforcing materials, mold release agents, coloring agents, accelerators, stabilizers, etc. may be used in combination with the allyl ester resin to further enhance the performance of the laminate.

In the present invention, the allyl ester resin described above can be used to produce a laminate according to known methods. In other words, cellulose fibers coated with melamine resin are impregnated with the above resin, a plurality of impregnated cellulose fibers are laminated, and in the case of metal foil-clad laminates, adhesive is pre-coated or coated on one or both sides. A laminate can be produced by stacking metal foils that do not contain metal foils, heating, curing, and forming them without pressure or under pressure. At this time, the metal foil may be attached after hardening and molding the impregnated laminated cellulose fiber.

The cellulose fibers used in the present invention may be the same as the cellulose fibers used in conventional laminates.
Cellulose paper such as kraft paper, linter paper, and Konoton paper, whose density when air-dried is 0 from the viewpoint of impregnation and quality.
Paper mainly composed of cellulose fibers having a weight of 3 to 0.7 g/cm 3 , such as kraft paper, is preferred.

As the metal foil in the present invention, electrolytic copper foil intended for use in silver foil-clad laminates for electrical circuits is commercially available.
Using this can improve corrosion resistance and engineering.

Although it is preferable from the viewpoint of anti-sticking properties and adhesion properties, the present invention is not limited thereto. The thickness of metal foil is 1
The thickness is preferably about 0 to 100 μm.

In order to effectively achieve adhesion between the metal foil and the resin-impregnated cellulose fibers, it is preferable to use an adhesive, which is a liquid or semi-liquid adhesive that does not generate unnecessary side reaction products during the curing process. Preferably. From this point of view, acrylate adhesives, epoxy adhesives, epoxy acrylate adhesives, isocyanate adhesives,
Alternatively, various modified adhesives may be used.

The thickness of the laminate of the present invention varies depending on the type of cellulose fiber, the composition of the cured resin liquid, and the use of the laminate, but is usually 5 to 5 mm. Moreover, the proportion of allyl ester resin in the laminate is 30 to 8 Qwt%.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples unless it departs from the gist of the present invention. Throughout this specification, all temperatures are in degrees Celsius, and parts and percentages are by weight unless otherwise specified.

[Example] Production Example 1 Production of allyl ester resin (1) In a 1Q reactor equipped with a distillation apparatus, /allyl terephthalate 60
0g (2,44mo +), 70 pyrene glycol 9
0.1 g of 5.9 g (1,26 mol) butyltin oxide was charged and heated to 180°C under a nitrogen stream to distill off the allyl alcohol produced. After distilling off 140 g (2.41 mol) of allyl alcohol, the pressure inside the reactor was reduced to 50 mmHg to accelerate the distillation rate. After allyl alcohol in an amount equivalent to propylene glycol was distilled off, the reaction solution was heated to 200 m
Unreacted diallyl terephthalate was distilled off at l m m Hg while maintaining the temperature at °C. The reaction solution was poured into a sieve, cooled, and pulverized to obtain a powdery allyl ester resin (1).

Production Example 2 Production of allyl ester resin (2) containing bromine Except for the conditions shown in Table 1, allyl ester resin (1
) to obtain a bromine-containing allyl ester resin (2).

Production Example 3 Production of unsaturated Boisester resin 100 g of propylene glycol and 832 g of isophthalic acid were charged into an IQ separable flask equipped with a stirrer, a thermometer, a gas inlet tube, and a condenser, and the condensed water was allowed to flow out under nitrogen bubbling conditions. The reaction was continued at 185°C for 3 hours. Next, 87.2 g of fumaric acid was added, and the mixture was reacted at 185°C for 6 hours. Finally, the pressure inside the system was reduced to about 12 mmHg, and the temperature inside the flask was raised to 200°C to complete the reaction, and a resin with an acid value of 30 was obtained.

This resin was dissolved in styrene to obtain an unsaturated polyester resin (1) having a styrene concentration of 47%.

Examples 1 to 3 Kraft paper with a basis weight of 155 g/m' and a thickness of 300 μm was soaked in the melamine resin compounded liquid shown in Table 2, squeezed with a roller, dried at 120° C. for 30 minutes, and coated. Ta.

Regarding the melamine resin, in the formulations shown in Table 2, Example 1 used formulation composition (1), Example 2 used formulation composition (2), and Example 3 used formulation composition (3).

The amount of resin attached to the obtained paper base material is as shown in Table 2.

This paper base material was mixed with 78 parts by weight of the resin shown in Table 1 (1), 1-20 parts by weight of n-butyl acrylate, and 1 part by weight of hemp/yl peroxide.
1 part by weight, / 1 part by weight of Kumil Pao beef side is impregnated with the resin liquid from one side of the final layer, and the 7 sheets are stacked, and one side is coated with copper foil (MK-6 manufactured by Mikata Metal Mining Co., Ltd.) with adhesive.
1) were superimposed and a 50 μm polyester film was laminated on both sides, followed by heating and pressure molding using a press machine.

Heating and pressing conditions are 140°C, 130 minutes, 30kg/cm'
Met. After pressing, heat in hot air drying oven at 150°C112
Heating was performed for 0 minutes to obtain a copper foil-clad laminate having a thickness of 1.4 to 13 mm. The test results of the copper foil clad laminate are shown in Table 3.

Example 4 Instead of 78 parts by weight of the resin in Table 1 (1) of Example 1,
A copper foil-clad laminate was obtained in the same manner as in Example 1, except that 73 parts by weight of the resin shown in Table 1 (2) and 5 parts by weight of antimony trioxide were used. The thickness of the obtained copper foil laminate was 1.6
It was mm. The test results for this copper foil-clad laminate are shown in Table 3.

Comparative Example 1 A copper foil-clad laminate was obtained in the same manner as in Example 1 except that it was not coated with a melamine resin. The test results for this copper foil-clad laminate are shown in Table 3.

Comparative Example 2 A copper foil-clad laminate was obtained in the same manner as in Example 4 except that it was not coated with a melamine resin. The test results for this copper foil-clad laminate are shown in Table 3.

Comparative Example 3 The copper A foil-clad laminate was obtained. The test results for this copper foil-clad laminate are shown in Table 3.

As is clear from Example 1 Comparative Example listed in Table 3, by coating the surface of cellulose fibers with melamine resin, Allyl has excellent hygroscopicity, electrical properties after moisture absorption, mechanical strength, and heat resistance. It can be seen that an ester resin/cellulose resin metal foil laminate can be obtained.

[Effects of the Invention] As explained above, the metal foil-clad laminate of the present invention has the following effects:
In metal foil-clad laminates made of allyl ester resin, a base material mainly composed of cellulose fibers, and metal foil, by substantially covering the surface of the cellulose fibers constituting the base material with melamine resin. It also has excellent properties such as less hygroscopicity, less deterioration of electrical properties after moisture absorption, and mechanical strength and heat resistance.

Claims (4)

[Claims] 1. A metal foil-clad laminate comprising an allyl ester resin, a base material mainly composed of cellulose fibers, and metal foil, characterized in that the surface of the cellulose fibers constituting the base material is substantially covered with a melamine resin. Metal foil laminate. 2. The metal foil-clad laminate according to claim 1, wherein the melamine resin is a methylolmelamine resin. 3. The metal foil-clad laminate according to claim 1, wherein the melamine resin is an alkyl alcohol-modified methylol melamine resin. 4. The metal foil-clad laminate according to claim 1, wherein the melamine resin is a hydroxyethyl methacrylate-modified methylol melamine resin.