JPH0349954A - Preparation of laminated sheet - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet excellent in surface smoothness, thickness accuracy and dimensional stability by heating an impregnated base material laminate under a substantial ly pressure-free condition to precure the same and subjecting the precured laminate to press molding under pressure to cure the same and subsequently cutting the molded laminate before curing the same under heating in a substantially pressure-free state. CONSTITUTION:A long fibrous base material is impregnated with a solvent non-containing thermosetting resin composition and a predetermined number of the impregnated ones are superposed to obtain an impregnated base material laminate which is, in turn, precured under zero-pressure or low pressure (usually, 3kg/cm<2> or less) not allowing the resin composi tion to flow out excessiviely. For example, the impregnated base materials are superposed and a release sheet or a metal foil is sandwiched therebetween if necessary to form the impregnated base material laminate which is, in turn, preheated while transferred through a heating oven under a substantially pressure-free condition to be precured. Next, the precured laminate is subjected to press molding under heating, for example, by using a continuous double belt press to form a continuous cured body which is then cut and post-cured under zero-pressure or low pressure (usually, 4kg/cm<2> or less) preventing deformation such as warpage. By this method, a laminated sheet free from the wrinkles of the metal foil, having no void inferiority and excellent in surface smoothness, thickness accuracy and dimensional stability is obtained.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing a laminate that has particularly excellent surface smoothness, thickness accuracy, and dimensional stability, and is free from void defects, and is particularly suitable for use in printed circuits. It is particularly useful for manufacturing substrates and the like.

<Prior Art> A method of continuously molding a laminate using a solvent-free liquid thermosetting resin composition is well known. For example, a long fibrous base material is impregnated with the above resin composition to create a resin-impregnated base material, and a predetermined number of these base materials are stacked one on top of the other, and if necessary, metal foil or cover film is pasted on both the top and bottom surfaces to form a continuous layer. A method of curing the laminate in a pressureless state or under a low pressure that does not cause excessive fluidization of the resin while passing the laminate through a heating furnace (Japanese Patent Laid-Open No. 56-98136)
(Japanese Unexamined Patent Publication No. 155440/1983), and a method in which the continuous laminate described above is semi-cured under no pressure and then completely cured by heating and pressure molding.

<Problems to be Solved by the Present Invention> However, since the laminate obtained by the above-mentioned pressureless forming method is cured without pressure, wrinkles occur in the metal foil on the surface, voids occur in the laminate, and the surface The problem is that the smoothness and thickness accuracy are poor.

As a solution to this problem, the method of performing the above-mentioned pressureless semi-curing and heat-pressing complete curing in series is effective, and the above drawbacks are solved at once, but molding is continued under pressure until the end of curing. Therefore, the tension applied to the laminate during the process remains as stress in the laminate, increasing dimensional shrinkage after etching and heat treatment, and reducing the dimensional stability of the resulting laminate. Furthermore, when a continuous double belt press is used for heat and pressure molding, in order to completely cure the product, a double belt press that is long enough to take the time required for complete curing is required, which poses a major economical problem.

<Means for Solving the Problems> As a result of intensive research under these circumstances, the present inventors impregnated a long fibrous base material with a solvent-free thermosetting resin composition, The impregnated base material laminate obtained by stacking a number of sheets is precured under virtually no pressure, either without pressure or under a low pressure (usually 3 kg/ci or less) that does not cause excessive flow of the resin composition, and then heated and pressure molded. After cutting the continuous cured product, it is post-cured under virtually no pressure, such as no pressure or a low pressure (usually 4 kg/ci or less) that prevents deformation such as warping, which was a problem with pressureless molding. Eliminates wrinkles and void defects in metal foil, improves surface smoothness, plate thickness accuracy,
The present inventors have discovered that a laminate with excellent dimensional stability can be obtained, and that the length of the double belt press can be economically reduced, leading to the completion of the present invention.

That is, the present invention provides a composition obtained by impregnating a long fibrous base material (I[) with a liquid thermosetting resin composition N) that does not contain a solvent (however, excluding polymerizable vinyl nitrate) and superimposing the composition. The impregnated base material laminate (In) is first precured by heating under substantially no pressure, then cured by heating and pressure molding, then cut, and then heated under substantially no pressure for post-curing. The present invention provides a method for manufacturing a laminate, which is characterized by:

Solvent-free liquid thermosetting resin composition (I
), for example, an addition reaction type resin and a curing agent that are liquid at room temperature as essential resin components, or a radical polymerizable resin that is liquid or solid at room temperature, a polymerization initiator, and a polymerizable vinyl monomer as essential resin components. A composition containing no solvent (excluding polymerizable vinyl monomers) and further adding additives such as a curing accelerator, an internal mold release agent, a pigment, and a filler as necessary. Further, examples include those that can be impregnated into a fibrous base material. Note that the solid component does not necessarily need to be dissolved or melted in the liquid component during impregnation (although it may be used in the form of a powder dispersed in the liquid component).

Typical examples of resins used here include addition reaction type epoxy resin; radical polymerization type epoxy vinyl ester resin, unsaturated polyester resin, diallyl phthalate resin, urethane acrylate resin, polyester acrylate resin, spiran resin, addition polymerization type There are polyimides, etc.

As the epoxy resin that can be used as the resin component in the present invention, any epoxy resin that is solvent-free liquid at room temperature or a mixture can be used, but usually one with an average epoxy equivalent of 100 to 400, preferably 100 to 250. use. Typical examples include epoxy resins obtained from epichlorohydrin, which is in a solution-free state at room temperature, bisphenol A, bisphenol F, and dihydric phenols; ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol. , glycerin, trimethylolethane, trimethylolpropane or -2
polyglycidyl ethers of polyhydric alcohols such as ethylene oxide or propylene oxide adducts of hydrohydric phenols; polyglycidyl ester acids of polycarboxylic acids such as adipic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid or dimer acid; cyclohexene or a cyclohexane-based epoxy compound (3,4-epoxy-6methyl-cyclohexyl-3
, 4-Epoxy-6=methylcyclohexane hydroxyl), 3.4-Epoxycyclohexylmethyl-3,
4-epoxycyclohexane carboxylate, 1-epoxyethyl-3,4-epoxycyclohexane, etc.);
Cyclopentadiene-based epoxy compounds (cyclopentadiene oxide, dicyclopentadiene oxide, 2,3 epoxycyclopentyl ether) obtained by epoxidizing cyclopentadiene or dicyclopentadiene or their derivatives with peracetic acid etc. ); limonene dioxide; or glycidyl ether ester of hydroxybenzoic acid. Among them, solvent-free liquid epoxy resin obtained from epichlorohydrin and bisphenol A is preferred because it has a good balance of performance and is inexpensive. Solvent-free liquid cyclohexene-based epoxy compounds are preferred because they provide good viscosity.

Furthermore, in the present invention, a mixture of one or more solvent-free liquid epoxy resins as described above and one or more epoxy resins having a melting point of 50°C or higher can also be used as the solvent-free liquid epoxy resin. A powdered epoxy resin having an average particle size of 50 to 500 μm, preferably 100 to 300 μm is used by dissolving and/or dispersing it in a solvent-free liquid epoxy resin. Typical examples include epoxy resins obtained from epichlorohydrin, all of which have melting points of 50°C or higher, and dihydric phenols such as bisphenol A, bisphenol F russorcin, tetrabromobisphenol A1, tetrabromobisphenol F1, and bisphenol S. or phenoxy resin; polyglycidyl ether of polyhydric phenol such as phenol, alkylphenol or brominated phenol novolak resin; 2
Co-condensed epoxy resin consisting of a functional phenol and a novolak resin; polyglycidylamine of a polyvalent amine such as aniline, p-(or m-)aminophenol, diaminodiphenylmethane, polyglycidyl ether of the above-mentioned polyhydric alcohol, polycarboxylic acid A collinear epoxy resin consisting of a polyglycidyl ester or a glycidyl ether ester of hydroxybenzoic acid and a dihydric phenol alone or a mixture of this and a monohydric phenol; triglycidyl isocyanurate, among others, from epichlorohydrin and bisphenol A. The resulting powdered epoxy resin has a good balance of performance and is inexpensive, and ultra-high molecular weight phenoxy resins, such as PKHH (trade name) manufactured by UCC Corporation in the United States, can provide high compression moldability and high performance with the addition of a small amount. Furthermore, powdered polyhydric phenol polyglycidyl ether has excellent heat resistance, and powdered epoxy resin obtained from epichlorohydrin and tetrabromobisphenol A and powdered brominated polyhydric 7-nol polyester Glycidyl ether is preferable since it has excellent flame retardancy.

Next, from the viewpoint of pot life, the curing agents for epoxy resins used together with the above epoxy resins in the present invention include aromatic polyamines, polybasic acid anhydrides, and boron trifluoride-amine complexes, which are latent curing agents. ), dicyandiamide and its derivatives, dibasic acid hydrazide,
Examples include diaminomaleonitrile and its derivatives, melamine and its derivatives, amines, imides, and polyamine salts, among which polybasic acid anhydrides are particularly preferred.

Typical polybasic acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, Trimellitic anhydride, pyromellitic anhydride, maleic anhydride, succinic anhydride, itaconic anhydride, citraconic anhydride, dodecenyl succinic anhydride, chlorendic anhydride, benzophenonetetracarboxylic anhydride,
Cyclopentatetracarboxylic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid, ethylene glycol bistrimelitate anhydride or glycerin trimellitate anhydride, etc. These can be used alone or in a mixture of two or more. Among them, liquid ones are preferred, such as methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, and the like.

In the present invention, a curing accelerator, other additives, etc. can be further added to the room temperature liquid epoxy resin and the curing agent for epoxy resin, if necessary.

Typical curing accelerators used here if necessary include diethylamine, triethylamine, diisopropylamine, monoethanolamine, jetanolamine, triethanolamine, methylethanolamine, methylgetanolamine, and monoisopropylamine. amines, nonylamines, dimethylaminopro- and lyamines,
Diethylaminoprobylamine, α-benzyljetanolamine i 2,4.6-Dolis-dimethylaminomethylphenol or its tri-2-ethylhexylate; 2-dimethylaminomethylphenol, pyridine, piperidine, N-aminopropylmorpholine, 1.8
- Various amines such as diazabicyclo(5,4,0)undecene-7 or its salts with phenol, 2-ethylhexanoic acid, oleic acid, diphenylphosphorous acid or organic phosphorous acids; 2-methylimidazole, 2- Isopropylimidazole, 2-undecylimidazole, 2
-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole,
Complexes of imidazole with metal salts such as Cu, Ni or Go; cyanoethylacine-type imidazoles obtained by reacting 2-methylimidazole with acrylonitrile, or their adducts with trimellitic acid or reactants with dicyandiamide. Imidazoles such as: RF, -monoethanolamine, BF2-benzylamine, BF.

Dimethylaniline, BF2-triethylamine, BF
BF2-Amine complexes such as 3-n-hexylamine, BFx 2,6-dimethylaniline, BP,-aniline or BF,-piperidinei Amine imide compounds starting from 1,1-dimethylhydrazine; triphenylphosphite and organic acid metal salts such as tin octylate.

Epoxy vinyl ester resins that can be used as the resin component in the present invention include various epoxy resins as described above, preferably bisphenol type or novolak type epoxy resins.
Examples include resins obtained by reacting each of them alone or in combination with the following unsaturated basic acids in the presence of an esterification catalyst.

Here, representative unsaturated basic acids include acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, monomethyl maleate, monopropyl maleate, monobutyl maleate, sorbic acid, and mono(2-ethylhexyl).
These include malate, and these can be used alone or in combination of two or more.

In addition, examples of polymerizable vinyl styrene include styrene, vinyltoluene, t-butylstyrene, chlorostyrene, or derivatives thereof such as divinylbenzene: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, etc. Acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, or 2-hydroxypropyl Low boiling ester monomers of (meth)acrylic acid such as (meth)acrylate; or trimethylolpropane tri(meth)acrylate, diprolene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate or (meth)acrylates of polyhydric alcohols such as 6-hexanediol di(meth)acrylate, etc. Among them, low-boiling ester monomers of styrene, vinyltoluene, and (meth)acrylic acid have excellent volatility. are preferred, and styrene is particularly preferred.

These can be used alone or in combination of two or more, but usually 60 to 20% by weight (total 10% by weight) based on 40 to 80% by weight of the epoxy vinyl ester resin.
0% by weight).

Further, a carboxyl group-containing epoxy vinyl ester resin obtained by reacting the above epoxy vinyl ester resin with a dibasic acid anhydride as described below can also be used as the epoxy vinyl ester resin in the present invention.

Here, typical dibasic acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride,
Methyltetrahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, maleic anhydride, succinic anhydride,
Among the representative examples of the polybasic acid anhydrides mentioned above are dibasic acid anhydrides such as itaconic anhydride.

Further, examples of the unsaturated polyester resin include those obtained by reacting dibasic acids containing unsaturated dibasic acids with polyhydric alcohols. Examples of the polymerizable vinyl monomer used together with the unsaturated polyester resin include the same polymerizable vinyl monomers as mentioned above. These can be added individually or as a mixture of two or more, but usually 40 to 80% by weight of unsaturated polyester.
It is used in a proportion of 60 to 20% by weight (total 100% by weight).

Typical unsaturated dibasic acids include maleic acid, maleic anhydride, fumaric acid, and 10-genated maleic anhydride; other typical acids that can be called saturated dibasic acids include Examples of polyhydric alcohols include phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, succinic acid, adipic acid, and sebacic acid.On the other hand, typical polyhydric alcohols include ethylene. Glycol, diethylene glycol, triethylene glycol, propylene glycol,
Dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, hydrogenated bisphenol A.

Examples include 1,6-hexanediol, adducts of bisphenol A and ethylene oxide or propylene oxide, glycerin, and trimethylolpropane.

In order to obtain epoxy vinyl ester resin or unsaturated polyester resin using each of these raw materials, conventionally known methods may be followed, and in preparing both of these resins,
It is recommended to use a polymerization inhibitor for the purpose of preventing gelation during resin preparation and for adjusting the storage stability or curability of the resulting resin.

Representative examples of such polymerization inhibitors include hydroquinones such as hydroquinone, pt-butylcatechol, and mono-t-butylhydroquinone; phenols such as hydroquinone monomethyl ether and di-tp-cresol; - Quinones such as benzoquinone, naphthoquinone, P-torquinone; or copper salts such as copper naphthenate.

The polymerization initiator that can be used in the present invention is preferably one that decomposes at a temperature lower than the heating and pressing temperature, such as cyclohexanone peroxide, 3,3.5
-) Limethylcyclohexanone peroxide, methylonexanone peroxide, CI-bis(t-butylperoxy) 3.3.5-trimethylcyclohexane, cumene hydroperoxide, dicumyl peroxide, lauroyl peroxide, 3, 5.5-) Limethylhexanoyl peroxide, benzoyl peroxide, di-myristyl peroxydicarbonate,
tButylperoxy(2-ethylhexanoate), t
Examples thereof include organic peroxides such as -butylperoxy-3,5,5-trimethylhexanoate, -butylperoxybenzoate, and cumylperoxyoctoate.

Among the above-mentioned resin components, an epoxy resin-based resin component is preferred, which essentially includes an epoxy resin and its curing agent, and further contains a curing accelerator if necessary, since it has excellent adhesive strength with the fibrous base material. In terms of quick curing, radical polymerizable resins, preferably epoxy vinyl ester resins and/or unsaturated polyester resins, radical polymerizable resins that essentially contain a polymerization initiator and a polymerizable vinyl monomer are preferred. Epoxy vinyl ester resin-based resin components are particularly preferred from the viewpoint of adhesive strength with solid substrates.

Furthermore, it is particularly preferable to use a combination of the above-mentioned epoxy resin-based resin component and radical polymerizable resin-based resin component, since moldability and performance of the obtained laminate are excellent. In this case, the exothermic peak temperature (hereinafter referred to as the "reaction exothermic peak temperature") when the temperature is raised at 10"C/@in using a scanning calorimeter.
Epoxy resin resin component (tB) of 140 to 200°C (
A) and reaction exothermic peak temperature (t8) of 80 to 160°C [
However, when it is mixed with the radical polymerizable resin component (B) of (t□)<(tA-IO), the effect is even more remarkable. Among these, the epoxy resin resin component (A) has a reaction exothermic peak temperature (tA) of 150 to 150, since the curing speed and resin composition outflow rate during heat and pressure molding are appropriate and the molding conditions have a wide allowable range. 190℃ is preferable,
In addition, as the radical polymerizable resin component (B), the resin component (B) can be preferentially reacted at low temperatures, so preliminary curing is easy, and the pot life is not short, so the reaction exothermic peak temperature is (tB) is 90-155℃ (
However, it is preferable that (tm) < (tA20)]. Reaction exothermic peak temperature (tB) is 140-200℃
In order to obtain the epoxy resin resin component (A) and the radically polymerizable resin component (B) having a reaction exothermic peak temperature (IB) of 80 to 160°C, it is necessary to Although the combinations and amounts may be selected as appropriate, typical examples are shown in Tables 1 and 2 below.

/' The weight ratio (A)/(B) of the above epoxy resin resin component (A) and radical polymerizable resin component (B) is usually 9.
The range is from 515 to 30/70, but the range from 93/7 to 40/60 is particularly important because the flow rate of the hot-press molded special resin composition is appropriate and voids and scratches are less likely to occur in the laminate. is preferred.

The filler to be added as necessary to the solvent-free liquid thermosetting resin composition (I) is appropriately selected depending on the required performance, working conditions, etc. Examples include aluminum hydroxide, aluminum silicate, and colloidal silica. , calcium carbonate,
These include calcium sulfate, mica, talc, titanium dioxide, quartz powder, zirconium silicate, glass powder, asbestos powder, diatomaceous earth, and antimony trioxide.

The method and order of blending each component to obtain the thermosetting resin composition (I) are not particularly limited, but after mixing the liquid components, solid components may be added in powder form. , dispersion or dissolution is preferred.

On the other hand, typical examples of the fibrous base material (II) used in the present invention include glass fibers, carbonate fibers, and aromatic polyamide fibers, with glass fibers being particularly preferred. Among these, glass fibers include E-glass, C-glass, A-glass, and S-glass from the viewpoint of their raw materials, but any of these types can be applied in the present invention.

Next, carbonated fibers include polyacrylonitrile fibers,
Examples include those manufactured using cellulose fibers, pitch, aromatic hydrocarbons, or carbon black as raw materials, and aromatic polyamide fibers are produced by the reaction of polyfunctional aromatic amines and aromatic polybasic acids. It is made from a polymer having an amide bond, and typical polymers include poly-p-phenylenetetraphthalamide and poly-p-aminobenzamide.

These fiber bases (II) can be divided into rovings, chopped strand mats, continuous mats, cloths, roving cloths, surfacing mats, and chopped strands depending on their shape. They are appropriately selected depending on the intended use and performance of the molded product, and if necessary, two or more types or shapes may be used in combination.

When obtaining a laminate according to the present invention, the volume ratio of the fibrous base material (n) is suitably within the range of 30 to 70% of the laminate.

In the manufacturing method of the present invention, the impregnated base material laminate is prepared under substantially no pressure (no pressure or a low pressure such that the resin composition does not excessively flow out (usually 3 kg/cli or less)) before hot-pressure molding. (III) is heated (hereinafter referred to as preheating) to preferentially react the radical polymerizable resin component (B) in the impregnated liquid thermosetting resin composition (I),
It is necessary to pre-cure the impregnated base material laminate (III), for example, by stacking one or more impregnated base materials and further curing with a release sheet, metal foil, etc. as necessary. Examples include a method in which the impregnated base material laminate (I[) is sandwiched and then preheated while moving in a heating furnace under substantially no pressure to precure.

This preheating may be performed under some pressure using a heating roll, heating belt, etc., as long as it is substantially under no pressure.

Furthermore, a non-contact heating method using far (near) infrared rays is also effective.

At this time, the preheating temperature is such that the reaction of the radical polymerizable resin component (B) progresses moderately, the reaction of the epoxy resin resin component (A) hardly progresses, and the temperature is within the allowable range of the heating and pressure molding conditions. <tm 60) ~ (t+
+20)°C range is preferred, especially (tB-20)~<
tm) 'c range is preferred. The preheating method is
It may be carried out at a constant temperature in the range of (tB-60) to (tB+20)'C, or may be carried out while changing the temperature, and is not particularly limited.

The preheating time varies depending on the content of the thermosetting resin composition (I), but the resin composition runoff rate (resin composition runoff rate when molded under heat and pressure at 170°C and 20kg/c4)
%) = W+ / W+l Preferably, the time when the weight becomes 1 to 10% by weight is particularly preferable. Usually, the time is 15 minutes or less, preferably 1 to 10 minutes.At this point, the resin composition inside the impregnated base material laminate still has sufficient tack, and it is judged that the resin composition at the cut end is sticky. (preferably in one state).

By this preheating, the temperature is higher than the reaction exothermic peak temperature (tB) of the resin composition (A), and 5 to 40 kg
/c4. Heat and pressure molding can be carried out over a wide pressure range, preferably from 10 to 30 kg/cl. That is, the radical polymerizable resin component (B) in the thermosetting resin composition (I)
) has been preheated to have a high molecular weight or become three-dimensionally reticulated, so even if the epoxy resin resin component (A) remains in the impregnated base material laminate (II) with a low molecular weight, it cannot be heated and pressurized. The outflow of the resin composition from the impregnated base material laminate (III) during molding is appropriately suppressed, and a laminate with excellent thickness accuracy and surface smoothness and no void defects can be obtained.

The hot-press molding may be carried out using, for example, a continuous double belt press, and in this case, two or more types of impregnated fibrous base materials may be combined. The molding temperature is (IA) relative to the reaction exothermic peak temperature (tA) of the epoxy resin resin component (A).
〜(tB+70)'C is preferable because the resin composition outflow amount and reaction rate during molding are appropriate and voids and scratches are less likely to occur in the laminate. Among these, (ta+S)〜(tB
+50)°C range is preferred.

The above heat-pressing molding is performed by post-curing the impregnated base material laminate (III) at a Tg (°C) lower by 4 to 30°C, preferably by 5 to 20°C, than the glass transition temperature Tg (°C) of the laminate obtained by post-curing.
If the process is finished when this point is reached, the laminate will be free from peeling between base materials during cutting, wrinkles on the surface of the laminate, and residual internal distortion, and will have excellent surface smoothness, thickness accuracy, and dimensional stability. It is preferable in that it can be obtained.

Next, the formed laminate is cut into a predetermined size, but at this time, it is preferable to cool the laminate before cutting.

The cut laminates are heated and post-cured one by one or stacked under no pressure. At this time, in order to prevent warping, pressure is applied to the extent that the stack of multiple laminates is compressed (
(usually 4 kg/c+j or less), as long as it is substantially pressureless.

At this time, post-curing by heating is usually (tA-20) to (
tA+70)° C. until complete or almost complete curing. In addition, complete or almost complete curing as used herein means that Tg (°C) does not increase much even if heated further, and
Refers to the cured state below ℃.

cormorant.

After heating and press forming as described above, cutting, and then completely or almost completely curing under substantially no pressure, it is applied to a fibrous base material because it has been continuously transferred from impregnation to heating and pressing process. Since the tension is released without remaining as internal stress in the laminate, a laminate with excellent dimensional stability can be obtained.

<Example> Next, the present invention will be described in more detail by giving examples and comparative examples. Note that parts and percentages in the examples are based on weight (excluding percentages of dimensional change).

In addition, the glass cloth used was all 0.18 inch thick unless otherwise specified.

Example 1 16.9 parts of a solvent-free liquid epoxy resin with an epoxy equivalent of 190 obtained by the reaction of bisphenol A and epichlorohydrin and an epoxy resin 26 with an epoxy equivalent of 370 obtained by the reaction of tetrabromobisphenol A with epichlorohydrin Epoxy resin composition (A-1) consisting of 43.4 parts of an epoxy resin mixture in which . Temperature (ta) of 162°C] was prepared.To this resin composition (A-1), an epoxy resin metafreely (60%
) and styrene monomer (40%), a radical polymerizable resin composition consisting of 30 parts of an epoxy vinyl ester resin composition, 0.3 parts of di-myristyl peroxycarbonate, and 0.2 parts of cumene hydroperoxide. (B-1) [reaction exothermic peak temperature (t+) 98°C] was added and mixed to form a solvent-unmixed liquid thermosetting resin composition (I-
1) was prepared.

This resin composition (I-1) was impregnated into eight continuous glass cloths each having a width of 1020 mm in separate impregnating baths, and then laminated. Copper foils with a thickness of 35 μm were laminated on the top and bottom, and the impregnated base materials were laminated. After obtaining the body (I[l-1), it was precured in a hot air heating furnace at 110° C. for 4 minutes under no pressure. At this time, the resin component content in the impregnated base material laminate excluding the copper foil was 45%.
Met. In addition, a sample of 300 mm x 30011 tl size was cut from the pre-cured impregnated base material laminate (lI [-1) at this time and heated at 170°C x 20 kg/cff.
When molded under heat and pressure under the conditions of 1, the resin flow rate was 3.
%Met.

The above pre-cured continuous impregnated base material laminate (■-4) 1
Conveyed to a continuous double belt press at 70℃, 20kg/
After heating and pressure molding at a pressure of cffl for 5 minutes, it was cooled to 100°C under the same pressure, and molded with a guillotine cutter at 100°C.
After cutting into mm length, both ends were cut. The cut surface was in good condition with no cracks on the cut surface. T of the laminate at this time
g('C) was 148°C. Tg (℃) is R5A-II (dynamic solid viscoelasticity measuring instrument) manufactured by Rheometric Co., Ltd.
The temperature was raised at 1° (:/min).

Furthermore, it was sandwiched between 2-thick stainless steel plates in a heating furnace at 160°C and cured for 1 hour.
A 000 laminate was obtained. Tg('C) at this time is 162
It was ℃. Furthermore, when heating was continued at the same temperature until there was no further increase in Tg (°C), the Tg ('C) at this time was 16
The temperature was 4°C.

The results of measurement and evaluation of physical properties are shown in Table 3.

Each physical property was measured or evaluated by the following method.

■ Thickness accuracy (+nm); 1000mm
The thickness of the 1,000 mm laminate at the position of the 5 cylinder part ■ inward from the center of one side on the left in the flow direction, the center part ■, and the 5 cylinder part ■ inward from the center of one side on the right side, respectively. It was measured.

■ Surface smoothness (μm) Part 7 Tokyo Seimitsu Surfcom 55
The roughness (μm) of the surface of the copper foil on the laminate was measured using 08.

■ Presence or absence of voids: The presence or absence of blistering of the copper foil occurring on the surface of the laminate was visually determined.

(2) Water absorption rate (%): After removing the copper foil on one side of the laminate by etching, a pressure Kunker test was performed for 4 hours at 120°C and 2 atmospheres, and the water absorption rate was calculated using the following formula.

(Wl Wo / Wo) After removing the foil by etching, it was heat-treated at 130° C. for 1 hour, and the dimensional change rate in the vertical and horizontal directions was calculated using the following formula.

(Lo L/ Lo) X 100Lo;
Length before heat treatment, L; Length after heat treatment, Comparative Example 1 After no-pressure preliminary curing, no-pressure heating was performed at 160 ° C. for 60 minutes to almost completely cure, and hot-pressure molding and post-curing were performed. A laminate was obtained in the same manner as in Example 1 except that the above steps were not carried out, and the physical properties were measured and evaluated in the same manner.The results are shown in the table below.
Shown in 3.

Example 2 and Comparative Example 2 A laminate was obtained in the same manner as in Example 1, except that the hot-press molding conditions and post-curing conditions were changed as shown in Table 3.
Next, physical properties were measured and evaluated in the same manner. The results are shown in Table-3.

Example 3 An epoxy resin composition (A-3) obtained in the same manner as in Example 1 except that the amount of benzyldimethylamine added was changed from 0.7 parts to 0.35 parts (reaction exothermic peak temperature (tA
) 168°C] and 1,1-bis(L-butylperoxy) 3 instead of 0.3 part of di-myristyl peroxycarbonate and 0.2 part of cumene hydroperoxide.
, 3. Radical polymerizable resin composition (B-3) obtained in the same manner as in Example 1 except for using 0.6 parts of 5-1-limethylcyclohexane (reaction exothermic peak temperature (tB)
A laminate was obtained in the same manner as in Example 1, except that the precuring was carried out at 120° C. for 4 minutes, and the physical properties were measured and evaluated in the same manner. The results are shown in Table-3. In addition, when heating was performed at the same temperature as post-curing until there was no further increase in Tg (°C), the Tg ('C) at this time was 1.
The temperature was 63°C.

Example 4 Instead of 30.5 parts of the radical polymerizable resin composition (B-1), bisphenol A type unsaturated polyester resin [Polylite FG-387 manufactured by Dainippon Ink & Chemicals Ltd.
) 20 parts and 1,1-bis(butylperoxy)
Examples except that 20.4 parts of a radically polymerizable resin composition (B-4) (reaction exothermic peak temperature (t++) 120°C) consisting of 0.4 parts of 3,3.5-trimethylcyclohexane were used. A laminate was obtained in the same manner as in Example 1, and then the physical properties were measured and evaluated in the same manner. The results are shown in Table-3. In addition, when heating was performed at the same temperature as post-curing until there was no further increase in Tg (°C), the Tg (°C) at this time was
was 164°C.

It was.

<Effects of the Invention> As is clear from the Examples and Comparative Examples, when completely cured without pressure (Comparative Example 1), problems occurred in thickness accuracy, surface smoothness, water absorption rate, etc. When completely cured (Comparative Example 2), the dimensional change rate becomes large.

According to the manufacturing method of the present invention, the above problems are solved all at once, and even if the production line speed is set to ensure appropriate productivity, the length of the double belt press will not be that long. It is economical.

Claims (1)

[Claims] 1. A long fibrous base material (II) is impregnated with a liquid thermosetting resin composition (I) that does not contain a solvent (excluding a polymerizable vinyl monomer), and The impregnated base material laminate (III) obtained in combination is first precured by heating under substantially no pressure, then cured by heating and pressure molding, and then cut.
A method for producing a laminate, characterized by post-curing by heating under substantially no pressure. 2. Even if heated further, the glass transition temperature will increase by 4℃
2. The method according to claim 1, wherein the cut impregnated base material laminate is post-cured until the impregnated base material laminate is cut. 3. 4 to 30°C above the glass transition temperature of the laminate obtained by post-curing the pre-cured impregnated base material laminate (III)
The manufacturing method according to claim 2, wherein the method is cured by heating and pressure molding until the glass transition temperature reaches a low glass transition temperature. 4. The impregnated base material laminate (III) is precured until the resin composition flow rate becomes 1 to 15% by weight when molded under heating and pressurizing conditions of 170° C. and 20 kg/cm^2. manufacturing method. 5. The exothermic peak temperature (t_A) of the solvent-free liquid thermosetting resin composition (I) when heated at 10°C/min using a scanning calorimeter is 140 to 200°C, and the epoxy resin An epoxy resin resin component (A) containing a curing agent and a curing agent as essential components has an exothermic peak temperature (t_B) of 80 to 160 °C when heated at a rate of 10 °C/min using a scanning calorimeter. t_
B)<(t_A-10)], and a resin composition formed by mixing a radical polymerizable resin component (B) containing a radical polymerizable resin, a polymerization initiator, and a polymerizable vinyl monomer as essential components. The method according to claim 4, which is a product. 6. Heat and pressure molding at a molding pressure of 5 to 40 kg/cm^2,
6. The manufacturing method according to claim 5, which is carried out at a molding temperature of (t_A) to (t_A+70)°C. 7. Preheat to (t_B-60) to (t_B+20)℃
7. The method according to claim 6, which is carried out at a temperature of .