JPH04129739A - Preparation of electric laminated sheet - Google Patents

Abstract

PURPOSE:To enhance electrical characteristics and solder heat resistance by performing the treatment of a paper base material with a melamine resin under a special treatment condition. and using an impregnating resin composition compounded with a radical curable resin as an impregnating resin. CONSTITUTION:In preparing an electrical laminated sheet using a radical curable resin, a base material based on a cellulose fiber impregnated with a melamine resin whose heat loss is 3% or less at 120 deg.C and 1-8% at 120-190 deg.C to be dried is used. In this case, as a base material, kraft paper or cotton cloth is designated. The melamine resin is used by dissolving a precondensate in a solvent such as methanol or water and impregnating the base material with the resulting solution. The radical curable resin means a resin wherein a compound having an unsaturated bond is subjected to chain polymerization by a free radical generated by heat, light or a catalyst to be cured and an allyl ester resin is designated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrical laminate used in electrical equipment, electronic equipment, communication equipment, etc., and a base material used therein.

[Conventional technology]

Conventionally, various types of laminates have been used for electrical circuits, but among those based on cellulose fibers, paper/phenolic laminates are mainly used in the field of single-sided copper-clad laminates for consumer use. has been done. It is cheaper than other laminates for electrical circuits, and currently accounts for most of the market for consumer use.

Furthermore, in recent years, there has been a movement to use glass fiber/epoxy laminates in addition to paper/phenol laminates in industrial OA equipment, etc., and there is a growing demand for laminates for electrical circuits with superior performance. It's been getting worse.

However, fer/fer resins have problems with the generation of reaction by-products during curing and removal of solvents, while epoxy resins have the same problems with solvent removal as described above.

In addition to the above resin systems, paper and unsaturated polyester resin systems have recently been developed. Although it is easy to use in radical reactions, it has low affinity for paper substrates, and as a result, the electrical performance, heat resistance, etc. of the metal foil-clad laminate deteriorates.

Attempts have been made to solve the above-mentioned affinity problem by pre-treating the base material with melamine resin, but this has not yet reached a satisfactory level, particularly in terms of soldering heat resistance.

[Problem to be solved by the invention]

The present inventors have aimed to produce an electrical laminate with excellent electrical properties and significantly improved solder heat resistance by appropriately controlling the pretreatment conditions of the paper base material. investigated.

[Means to solve the problem]

As a result of intensive research in order to solve the above object, the inventors of the present invention have developed a method for impregnating paper by treating paper base materials with melamine resin under special processing conditions. They discovered that the problem could be solved by using a resin composition and completed the present invention.

That is, the gist of the present invention is that when producing an electrical laminate using a radical curable resin, the heating loss at 120°C is 3% or less, and the heating loss between 120°C and 190°C is 1%. The manufacturing method is characterized in that it is carried out using a base material whose main component is cellulose fibers impregnated with a melamine resin or dried at a concentration of 8%.

Conventionally, there are known examples that specify the volatile content at a temperature of 150'C, for example, but when considering the reaction of melamine resin and the water absorption properties of the paper base material, it cannot be determined unambiguously and is unreasonable. It is enough. As a result of various studies, the inventors of the present invention found that the weight loss value due to heating at 120'C is mostly due to water and solvent contained in the paper and melamine resin, and the weight loss value when heated at 190°C. It was found that the value was due to a condensation reaction of melamine resin.

The present invention controls the heating loss at 120° C. and 190'C of the paper base material treated with the melamine resin as heating loss having different meanings when manufacturing an electrical laminate using a radical curable resin. As a result, the solder heat resistance has been significantly improved.

Hereinafter, the content of the present invention will be explained in detail.

(A) A base material whose main component is cellulose fiber.

Typical examples of the base material used in the present invention include kraft paper, cotton linter paper, cotton cloth, and the like.

Bleached kraft paper is most commonly used, but is not limited to this.

(B) Melamine resin Melamine resin is generally produced by dissolving an initial condensate in a solvent such as methanol or water and applying it to a cellulose fiber base material by dipping it. The treated material may be used as a base material.

In the present invention, the heating loss of the base material mainly composed of cellulose fibers impregnated with melamine resin and dried is 120
℃, it is 3% or less, preferably 2% or less. and 1% to 8% from 120°C to 190'C
, preferably 2% to 6%. If the heating loss at 120°C exceeds 3%, sufficient soldering heat resistance cannot be obtained.
The same applies when the loss on heating between 120°C and 190°C exceeds 8%. Also from 120℃ to 190'C
If the heat loss during heating does not reach 1%, blistering or delamination will occur during the production of the laminate. This is thought to be because the condensation reaction progresses too much during drying of the melamine resin, resulting in a decrease in affinity with the impregnated resin composition.

The heating loss referred to in the present invention is determined by the following formula.

In addition, each heating condition is 1 at 120'C.
0 minutes, and further 20 minutes at 190° C., and weighing is performed immediately after heating.

Moreover, the melamine resin-treated base material before heating is taken from the base material just before impregnation with the radical curable resin composition.

The general formula below is as follows.

-bb-c X= X100 Y=
xlOOa
bX: Loss on heating at 120°C (wt%) Y: Loss on heating between 120°C and 190°C (wt%) a: Weight of the treated substrate before heating! (g) b: ] Weight of the treated substrate after heating at 20'C (g) c: 1
Weight of the treated base material after heating at 90'c (g) By using the melamine resin treated base material that has undergone heat loss control in this way, it has good electrical properties and significantly improved soldering heat resistance. An electrical laminate with good quality can be obtained.

The melamine resin used in the present invention refers to a condensate of melamine and formaldehyde, a condensate obtained by converting the condensate with a lower alcohol such as methanol, and a group capable of condensing with a methylol group that they have. Refers to a reaction or mixture of aliphatic derivatives with For example, for N-methylolmelamine, methoxylated N-methylolmelamine, 2-hydro+7 ethyl (meth)acrylate, glyc/zyl (meth)acrylate, ethylene glycol monoallyl ether, polyethylene glycol mono (meth)acrylate, polypropylene glycol. Things (
meth)acrylate, glycerin shear norether,
Examples include those obtained by reacting or mixing methacrylic acid, N-methylolacrylamide, etc., but usable substances are not limited thereto. The amount of these melamine-based resins attached is 5 to 30 parts by weight based on the base material ioo' whose main component is cellulose fiber. If it is less than 5 parts by weight, the water absorption rate of the produced laminate will be high, and if it exceeds 30 M parts by weight, the impact strength of the laminate will decrease.

(C) Radical curable resin The radical curable resin referred to in the present invention refers to a resin that is cured by chain polymerization of a compound having an unsaturated bond by free radicals generated by heat, light, or a catalyst. For example, unsaturated polyester resin,
Refers to vinyl ester resin, diallyl phthalate resin, allyl ester resin, etc.

The above-mentioned allyl ester resin 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 anhydride, inphthalic acid, phthalic acids such as terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, and methylendomethylenetetrahydrophthalic acid. acid,
Hexahydrophthalic acid, methyl hexahydrophthalic acid,
and hydrophthalic acids such as their acid anhydrides, aliphatic dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, tetrabromophthalic acid, tetrachlorophthalic acid, chlorendic acid, and acid anhydrides thereof, etc. Examples include halogenated dibasic acids. Trimellitic acid and pyromelli are polybasic acids with higher acid functionality.

Examples include toric acids and their acid anhydrides. These can be used alone or in combination.

Saturated polyhydric alcohols include ethylene glycol, 1
, 2-propylene glycol, 1,4-butanediol, ] + 6-hexanediol, neopentyl glycol, 1,4-7 chloromethane diol, paraxylene glycol, etc., aliphatic, alicyclic or aromatic In addition to the divalent alfur containing, the general formula HO (CHRCH, ○)
. A dihydric alcohol obtained by the addition reaction of fullylene oxide such as ethylene oxide or propylene oxide, which is prepared by H (R is H or CsHtm**, m is an integer of 1 to 5, and n is an integer of 2 to 10). can be given. 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. Further examples include aliphatic, alicyclic or aromatic halogenated polyhydric alcohols containing a halogen atom, such as Zig0 moneobentyl glycol and tetrabromobisphenol A ethylene oxide adduct. 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, an allyl ester resin is produced by charging a diallyl ester of a saturated dibasic acid such as diallyl terephthalate and a saturated polyhydric alcohol together with a transesterification catalyst into a reactor and reacting the allyl alcohol while distilling off the allyl alcohol. A more industrially effective method is to charge a dialkyl ester of a saturated dibasic acid, such as dimethyl terephthalate, in place of diallyl terephthalate, together with allyl alcohol, polyhydric alcohol, and a transesterification catalyst, to remove by-produced alcohols such as methanol. It can be obtained by reacting while distilling off.

Further, depending on the reaction temperature, a polymerization inhibitor such as hydrochloride may be allowed to coexist 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 types of allyl ester resins that can be used in the present invention may be one type or a mixture of two or more types. By selecting various types of saturated polybasic acid and saturated polyhydric alcohol, a laminate with a good balance of heat resistance, electrical properties, etc. can be obtained.

In producing the laminate in the present invention, a radically polymerizable crosslinking monomer can be used together with the above-mentioned radical curable resin, and any known ones can be used, but for example, diallyl orthophthalate, diallyl iso phthalate, diallyl phthalates such as diallyl terephthalate, styrene, α-methylstyrene,
Substituted styrenes such as p-methylstyrene, p-chlorostyrene, bromstyrene, divinylbenzene, (
Methyl acrylate, ethyl (meth)acrylate,
Butyl (meth)acrylate, (2-ethylhexyl methaneacrylate, lauryl (meth)acrylate, (meth)
Acrylic acid or methacrylic acid esters such as benzyl acrylate, fromated phenyl (meth)acrylic ester, ethylene glyfur di(meth)acrylate, 1゜4-butanediol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate,
Vinyl polyfunctionals such as noacrylated isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerin di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, etc. Acrylic acid or methacrylic esters, polyurethane (meth)acrylate, polyether (
Vinyl polyfunctional oligoesters such as meth)acrylate, epichlorohydrin-modified bisphenol A di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polybrobylene glycol di(meth)acrylate are included.

There is no problem in using two or more types of crosslinking monomers in combination depending on the purpose. In the present invention, by blending a crosslinking monomer, the viscosity of the radical curable resin, which is originally a solid or viscous liquid, can be lowered, and the manufacturing process of the laminate can be improved without going through the prepreg state using a solvent or the like. It can be simplified.

The radical curable resin composition of the present invention can be cured using a general-purpose organic peroxide, and can be used together with an organic peroxide or alone for polymerization initiators sensitive to light, radiation, and electron beams. Known polymerization initiators such as 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) 3,3,5-1-limethylcyclohexane, and n-butyl- Peroxy ketals such as 4,4-bis(t-7' tylperoxy)valerate, hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-butyl Peroxide, dicumyl peroxide, 2,5-dimethyl-25-di(t-butylperoxy), dialkyl peroxides such as beef san, diasilver oxides such as lauroyl peroxide and benzoyl peroxide, di-1so - Peroxy/dicarbonates such as propylperoxydicarbonate, dimyristylbaroxydicarbonate, bis(4-1-butylcyclohexyl)peroxydicarbonate, t-butylperoxydiviparate, t-butylperoxydicarbonate/-2- Veroxine esters such as ethylhexanoate and t-butyl peroxy/benzoate can be mentioned. These can be one type or a mixture of two or more types,
It can be used depending on the type of resin and curing conditions.

In the present invention, fillers, reinforcing materials, mold release agents, colorants, curing accelerators, stabilizers, etc. may be used in combination with the resin composition as necessary to further enhance the performance of the laminate.

The resin composition of the present invention can be used to produce laminates by known methods.

(D) Preparation of Laminate A cellulose base material is first impregnated with a melamine resin solution.

The melamine resin content is adjusted by adjusting the degree of dilution of the melamine resin with a solvent or by appropriately selecting the type of solvent. It is also possible to adjust the degree of squeezing of the liquid by passing it through a spacer after immersion. The weight loss on heating of the melamine resin can be adjusted freely by changing the drying conditions after immersion in the melamine resin, but it is usually completed by passing the melamine resin through a hot air drying oven for a predetermined period of time.

If the treated substrate is stored indoors without being impregnated with the radical curable resin composition immediately after the drying process, it will rapidly absorb moisture from the atmosphere and its loss on drying at 120°C will increase. This would deviate from the purpose of the invention. Specifically, in the present invention, after drying the treated substrate, impregnation is performed before moisture is absorbed, or if water has been absorbed, impregnation is carried out after drying the treated substrate to remove the moisture absorption. It is important to do so.

The method of impregnating the base material impregnated with the melamine resin with the resin composition for impregnation is not particularly limited, and it is sufficient that the base material is uniformly impregnated with the resin composition. Next, the required number of base materials impregnated with the resin composition are laminated according to the desired thickness, and the laminated plates are obtained by pressing the base materials while heating. This method is not particularly limited either, and a commonly used batch press method, a method of continuously passing through a heating furnace and curing, etc. can be used.

The heating conditions are usually 8O-IBO'C for about 10 to 60 minutes, but depending on the selection of the curing agent, it is also possible to mold at lower temperatures and for shorter times, which may be considered in accordance with the manufacturing conditions. Further, post-curing is also possible if necessary.

Further, ordinary paper yarn laminates are mainly copper-clad.

Therefore, a copper-clad laminate can be obtained by simultaneously bonding a copper foil during the above-mentioned heating and pressure bonding, or by bonding a copper foil to a pre-cured laminate.

In recent years, there has been an increase in demand for laminates for additive circuits that are not bonded with copper foil, but the present invention is applicable without any limitations.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples unless it departs from the gist of the invention.

Production Example 1 Production of allyl ester resin (1) Diallyl terephthalate 60 was added to 11 reactors equipped with a distillation apparatus.
0g (2,44mob), propylene glycol 9
5.9g (1,26■0I2) and 0.1g of dibutyltin oxide were charged and heated to 180°C under a nitrogen stream.
Allyl alcohol produced was distilled off. When 140 g (2,41 mof2) of allyl alcohol had been distilled off, the pressure inside the reactor was reduced to 50 mmHg and the distillation rate was determined. After allyl alcohol in an amount equivalent to propylene glycol was distilled off, the reaction solution was distilled to 200 ml using a thin film distiller.
Unreacted diallyl terephthalate was distilled off at 1 @sh while maintaining the temperature at °C. Pour the reaction solution into a vat,
The mixture was 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).

Implementation 1 to 5 and Comparison 1 to 3 Kraft paper with a weight of 155 gem" and a thickness of 300 μ" was mixed with melamine resin (S-305 manufactured by Nippon Carbide Co., Ltd.) in water.
After soaking in a methanol solution and air drying, it was dried in a hot air dryer to obtain melamine-treated substrates having various heat loss values as shown in Table 2. The amount of melamine resin adhered to 100 parts by weight of Naori raft paper was 20 parts by weight. Immediately after drying, these substrates were immersed in the formulation of the allyl ester resin composition shown in Table 2 before absorbing moisture.

However, in Comparative Examples 2 and 3, the samples were left indoors for 5 hours after drying and then immersed. After impregnating with resin liquid and stacking 7 sheets, adhesive-coated copper foil (MK-61 manufactured by Mitsui Mining and Mining Co., Ltd.) is layered on one side, and 50 μm polyester film is layered on both sides, heat and pressure are applied using a press machine. Molded. The conditions are 160℃
-5 minutes - 30 kg/cm''. After pressing, it was heated at 170°C for 15 minutes in a hot air drying oven, and the thickness was 1.611 mm.
A copper-clad laminate of I11+ was obtained. Table 3 shows the results of measuring the physical properties of the copper-clad laminate.

Table 1 Raw material for allyl ester resin production DATP Nidialyl terephthalate DBNPG: ';Flamneopentyl glycol*1 Halogen content in product resin As is clear from the results in Table 3, the electrical grade obtained by the present invention It can be seen that the laminate has excellent solder heat resistance and also has good electrical properties.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to manufacture an electrical laminate having good electrical characteristics and significantly improved soldering heat resistance.

Claims (2)

[Claims] (1) When manufacturing an electrical laminate using a radical curable resin, the loss on heating at 120°C is 3% or less, and the loss on heating between 120°C and 190°C is 1% to 8%. A method for producing an electrical laminate, characterized in that the method is carried out using a base material whose main component is cellulose fiber impregnated with a melamine resin and then dried. (2) The method for manufacturing an electrical laminate according to claim 1, wherein the radical curable resin is an allyl ester resin.