JPS588732A - Production of prepreg sheet - Google Patents

Abstract

PURPOSE:To obtain inexpensively a prepreg sheet having excellent storage stability, by impregnating a substrate with a resin compsn. consisting of an epoxy resin, a polymerizable unsaturated compd., glycidyl methacrylate, etc. and then irradiating the impregnated substrate with light. CONSTITUTION:40-70pts.wt. epoxy resin having at least two epoxy groups per molecule, 20-57pts.wt. compd. having at least two polymerizable unsaturated groups per molecule such as propylene glycol diacrylate, 3-10pts.wt. glycidyl methacrylate, 0.5-5phr of a compd. capable of generating a radical by light irradiation such as benzoin, and 1-5phr of a compd. capable of generating a Lewis acid by heating, such as a BF3/monoethylamine complex, are mixed together. A substrate is impregnated with the resulting resin compsn. and irradiated with light to obtain the titled prepreg sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing prepreg sheets. More specifically, the present invention relates to a method for manufacturing a prepreg sheet that aims to save resources and energy in the manufacturing process and also provides excellent properties.

Generally, prepreg sheets are made by impregnating paper, glass cloth, polyester fiber, polyamide, or polyimide paper with a resin, and then applying heat to semi-cure the resin to form a prepreg sheet.

Conventionally, the resin used to obtain the above-mentioned prepreg state has been mixed with a phenol resin, a sauce such as methanol, toluene, methyl ethyl ketone, etc. to reduce the viscosity.

After these resin compositions are impregnated into a base material, the solvent is evaporated by heating, and the composition is B-staged, that is, semi-cured and tack-free.

However, with this method, if heating is continued during B-staging, the curing reaction will progress to the A-stage, so in B-staging, the thermosetting reaction is stopped at an appropriate stage, so the temperature is always constant. It is difficult to achieve a prepreg state, and the prepreg sheets obtained in this way have poor storage stability.Furthermore, since solvents are used in the resin composition, volatile solvents are not used to prevent pollution and preserve the working environment. It is necessary to process the prepreg sheet, making the manufacturing cost of the prepreg sheet high.

As a result of intensive research to overcome the above-mentioned drawbacks, the present inventors have developed an epoxy resin having at least two or more epoxy groups in the molecule, a compound having two or more polymerizable unsaturated groups in the molecule, A base material is impregnated with a composition containing glycidyl methacrylate, a compound that generates radicals when irradiated with light, a compound that generates radicals when heated, and a compound that generates a Lewis acid when heated, and a prepreg state is obtained by irradiating light. We have discovered that by using two chemical reactions with completely different polymerization mechanisms, we can create a prepreg sheet that provides excellent properties at low cost while saving resources and energy in the manufacturing process. This led to the completion of the present invention.

When a substrate impregnated with the resin composition as described above is irradiated with light, a compound having two or more polymerizable unsaturated groups in the molecule in the composition and glycidyl methacrylate copolymerize due to radical polymerization. The molecular weight is three-dimensionally increased, and the epoxy resin having at least two or more epoxy groups in the molecule is trapped in the network chain in an unreacted state. This state is the prepreg state in the present invention,
It is semi-cured and tack-free. Since this step is carried out at room temperature and no solvent is used in the resin composition, the curing reaction of the epoxy resin based on ionic polymerization hardly progresses and there is no solvent volatilization. Therefore, the prepreg sheet obtained by the manufacturing method of the present invention has good storage stability, good reproducibility, and low manufacturing cost.

The prepreg sheet obtained in this way is taped or laminated as a tape, and under pressure,
By heating at 00°C, it becomes a hardened structure or a laminate.

Here, we will discuss the relationship between the topology of cured resin and its practicality. The cured product obtained by polymerizing compounds with different polymerization mechanisms in two stages is called PN (interpenetr).
ating Polymer Netvvolks;
It often takes the form of an interpenetrating network. It was confirmed that the resin composition in the present invention also consists of an epoxy group (which undergoes ionic polymerization) and an unsaturated group (which undergoes radical polymerization), and the cured product has a poly-PN structure. The radical polymerization component is used as the first mesh, and this is called the "base polymer". The system in which this is performed first will be referred to as "inverse PN J."
, Sci, -Phys,, B17y787-802+
1980). Changes in topology are thought to have an impact on practicality, and actual measurements revealed that normal PN exhibits better physical properties than inverse PN. Glycidyl methacrylate is one of the versatile compounds that has both an ionic polymerization component and an ionic polymerization component.When we conducted a synthesis experiment on the above-mentioned engineered PN structure in which this compound was blended as an essential component, we found that the first-stage mesh A cross-linked polymer structure in which the and second-tier networks were partially connected by chemical bonds was created.This was named [partially grafted PN J].We conducted a rough and detailed physical property study of the partially grafted PN. It was found that the physical properties varied greatly depending on the parent polymer and the grafting ratio, and it was concluded that this was due to the size of the interface in the microphase-separated structure. After all, in such a system [partial graft normal I
It has been found that PNJ exhibits excellent physical properties.

The conditions for the above effect to appear are shown below,
Detailed Description of the Contents of the Present Invention Examples of the resin having at least two or more epoxy groups in the molecule used in the present invention include 2,2'-bis(p-hydroxyphenyl)propane, 2, 2'-bis(4-hydroxy-3,5-dibromophenyl)propane, li
+:12-+) Rakis(p-hydroxyphenyl)ethane, 4,4-dihydroxydiphenyl, resorcin,
Glycidyl ethers of aromatic phenols such as catechol and hydroquinone, as well as glycidyl ethers such as phenol novolak and cresol novolak, as well as vinylcyclohexene diepoxide, limonene diepoxide, dicyclopentadiene diepoxide, (5', 4
-Epoxycyclohexylmethyl)-3,4-epoxycyclohexanecarboxylate, (6,4-epoxy-6-methylcyclohexylmethyl)-3,4-epoxy-6-methylcyclohexanecarboxylate, 5
-(5',4-epoxycyclohexyl)-2,4-dioxaspiro(5,5)-8,9-epoxyundecane, and 6-(glycidyloxyethoxyethyl)-2
゜Alicyclic epoxy resins such as 4-dioxaspiro(5,5)-8,9-epoxyundecane, and heterocyclic epoxies such as triglycidyl isocyanurate, the N,N'-diglycidyl derivative of 5,5-dimethylhydantoin Examples include resin. Any of these can be used alone or in combination. Note that an epoxy compound containing one epoxy group in the molecule may also be blended as a diluent.

Compounds having two or more polymerizable unsaturated groups in the molecule used in the present invention include α,β-unsaturated dibasic acids such as maleic anhydride and hexamaric acid, and ethylene glycol 1.
Polyhydric alcohols such as propylene glycol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol, and/or heptalic anhydride, isophthalic acid, terephthalic acid, adipic acid, tetrahydrophthalic anhydride, -1,1°--trimer Unsaturated polyester obtained by blending and copolymerizing polybasic acids such as toric acid and pyromellitic acid, and polybasic acids with terminal carboxylic acids obtained by polymerizing one or more compounds selected from the above compound group. Examples include allyl compounds obtained by reacting allyl alcohol with allyl alcohol, and (meth)acrylic acid esters of polyhydric alcohols.

Here, in this specification, (meth)acrylic ester means acrylic ester and/or methacrylic ester, and (meth)acrylate means acrylate and/or methacrylate.

Furthermore, monofunctional vinyl monomers such as styrene, vinyltoluene, α-methylstyrene,
Diaryl phthalate, (meth)acrylic acid esters, etc. may be used in combination.

However, the most preferred compound used in the present invention having two or more polymerizable unsaturated groups in its molecule is polyhydric alcohol (meth)acrylic It is an acid ester. Examples of (meth)acrylic esters of polyhydric alcohols include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate,
of aliphatic polyhydric alcohols such as neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolethane tri(meth)acrylate 1 pentaerythritol tetra(meth)acrylate ( meth)acrylic acid esters or di(meth)acrylates of bis(hydroxyalkyl) esters or bis(hydroxyalkoxyl) esters of terephthalic acid, isophthalic acid, phthalic acid (where the alkyl group is, for example, ethyl, propyl, neopentyl, etc.) , as the alkoxyl group, for example diethyl ether,
dipropyl ether, etc.) or di(meth)acrylates of bis(hydroxyalkyl) esters or bis(hydroxyalkoxyl) esters of tetrahydrophthalic acid, hexahydrophthalic acid, methylnadic acid, etc., and vinyl. monomers, such as glycidyl (meth)acrylate, hydroxyalkyl (
Monomers with vinyl groups and other functional groups such as meth)acrylate (alkyl groups such as ethyl and propyl), (meth)acrylic acid, and methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl ( Examples include one or a combination of two or more alkyl esters of (meth)acrylic acid such as meth)acrylate.

Here, the blending ratio of the resin raw material group is 40 to 70 parts of epoxy resin having at least two or more epoxy groups in the molecule, and 20 to 57 parts of compound having two or more polymerizable unsaturated groups in the molecule. % and glycidyl methacrylate is preferably in the range of 3 to 10 parts. The blending ratio of glycidyl methacrylate was determined from the relationship between the grafting rate and the physical properties of the cured product as described above, and when blending the epoxy resin and unsaturated compound, if the epoxy component exceeds the above range (i.e. If the unsaturated component is too low (outside of the above range), it will be difficult to maintain a good prepreg condition, and the surface of the prepreg sheet will become sticky or stick to itself when stacked. (That is, if the amount of unsaturated components exceeds the above range), there is a risk that the properties of the prepreg sheet after heat curing, particularly the heat resistance, will deteriorate, and both are unfavorable.

Examples of compounds that generate radicals upon light irradiation used in the present invention include benzoin, benzoin derivatives such as benzoin ethyl ether, quinones such as anthraquinone, sulfide compounds such as diphenyl disulfide, ketones such as Michler's ketone, and carbon tetrabromide. The amount of these added is preferably in the range of 0.5 to 5 phr; if the amount exceeds the above range, not only will the properties of the cured product of the unsaturated compound deteriorate, but also the economy will be affected. If the amount exceeds the above range, the photocuring speed will drop significantly, which is not preferable.

Compounds that generate Lewis acids upon heating used in the present invention include, for example, BF3, amine complexes, etc., and the amount added depends on the post-processing conditions of the prepreg sheet.
It may be determined according to the heating temperature, heating time, etc.), but it is preferably 1 to 5 phr.

The above-mentioned base material is impregnated with the resin composition obtained in this way, and irradiated with light using a lamp that efficiently generates light with a wavelength of 280 to 400 mm, such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, etc. By doing this, a good prepreg sheet can be obtained.

Next, the present invention will be explained in detail with reference to Examples.

Example 1 Tetraethylene glycol diacrylate 4 was added to 409 and 109 respectively.
09, a resin composition containing 109% of glycidyl methacrylate, 19% of benzoin butyl ether (BB Engineering) and 1.59% of BF3/monoethylamine complex (BF3/ME) was used as a glass cloth base material (L-927 manufactured by Arisawa Seisakusho Co., Ltd.)
5' S-110500mm
), irradiation speed 4rrV', irradiation distance 100mm
Light irradiation was carried out four times to obtain a prepreg sheet. The obtained prepreg sheet is designated as p-1.

Example 2 409 of Epicote 1001 and 15p of Epicote 828 8.1m) 40g of IJ methylolpropane triacrylate, 5g of glycidyl methacrylate,
Light irradiation was carried out in the same manner as in Example 1 for a resin composition containing 1 g of BE and BF3/MEL, 59.
I got prepreg sheet. The obtained prepreg sheet is designated as P-2.

Example 6 459 of Ebicoat 1001 and uni-8200 (manufactured by Dainippon Ink & Chemicals Co., Ltd., main component Evogyacrylate) 159, 65 g of limethylolbroban triacrylate, 5 g of glycidyl methacrylate, BEI 29 and BF3/MEi, 59 were combined. The resulting resin composition was irradiated twice with light in the same manner as in Example 1 to obtain a prepreg sheet. The obtained prepreg sheet is designated as p-3.

Test Example 1 Prepreg sheets p-1 and p- obtained in Examples 1 to 6
2 and p-3, surface dryness to the touch, storage stability,
Resin content and greenness were both found to be good.

Approximately 3 mm) was obtained. For each, bending strength temperature characteristics (25° 0.100° 0.160° 0), breakdown voltage (room temperature, in oil) and insulation resistance (unboiled 25° as 2
After boiling in water for an hour (25°O) was measured.

The measurement results are shown in Table 1.

Table 1 As is clear from Table 1, the prepreg sheet obtained by the production method G of the present invention exhibits excellent properties as a hardened structure or as a laminate product.
Shin - (1 other person)

Claims (3)

[Claims] (1) Epoxy resins having at least two epoxy groups in the molecule, compounds having two or more polymerizable unsaturated groups in the molecule, glycidyl methacrylate, compounds that generate radicals when exposed to light, and compounds that generate Lewis acids by heating. A method for producing a prepreg sheet, which comprises impregnating a base material with a resin composition containing the generated compound and converting it into a prepreg state by irradiation with light. (2) The method for producing a prepreg sheet according to claim 11, wherein the compound having two or more polymerizable unsaturated groups in the molecule is a (meth)acrylic acid ester of a polyhydric alcohol. (3) 40 to 70 parts by weight of an epoxy resin having at least two or more epoxy groups in the molecule, 20 to 57 parts by weight of a compound having two or more polymerizable unsaturated groups in the molecule, and 6 to 6 parts by weight of glycidyl methacrylate. 10 parts by weight, 0.5 to 5 phr of the compound that generates radicals when irradiated with light, and 1 to 5 phr of the compound that generates Lewis acid when heated, as described in claim 1) or 2). manufacturing method of prepreg sheet.