JPH01286838A - Metallic foil plated laminate - Google Patents

Abstract

PURPOSE:To contrive improvements in heat resistant and peeling strength of solder, by a method wherein an adhesive agent layer of a specific thickness is possessed on a metallic foil part side of an adhesive agent layer part and a mixed layer of the adhesive agent and curing unsaturated resin is formed on a laminated body part side. CONSTITUTION:An adhesive agent applied to a metallic foil is cured partly by heat-treating the same. A base material is impregnated with a curing unsaturated resin solution, a plurality of the base materials impregnated with the resin solution are superposed upon one another and made into a liquid resin impregnated laminated body. The metallic foil with the partly cured adhesive agent and the liquid resin impregnated laminated body are superposed upon each other and the adhesive agent and curing unsaturated resin are heated and cured. It is a necessary condition that a single layer of an adhesive agent for the metallic foil possesses a thickness of at least 5mum on a metallic foil part out of an adhesion layer part. Besides a contributing action to adhesive force with a metal, it functions sufficiently in mitigation of stress, and peeling strength of the metallic foil is improved. A reason why a mixed layer is made necessary condition besides the single layer of the adhesive agent is that traditional way of thinking of an improvement in adhesive force is used. Ordinarily, this is based on compatibility between different kinds of resin and the layer prevents ply separation of both the resin.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to metal foil-clad laminates, and particularly relates to metal foil-clad laminates for electronic circuits with excellent beer strength and solder heat resistance. Studies have been conducted on the boundary conditions between the metal foil adhesive and the resin constituting the impregnated resin liquid-containing laminate, and it has been found that an appropriate mixed layer is formed in the area where the two come into contact. What is needed is well known. (For example, regarding paper-based phenolic resin laminates, refer to the "Adhesion Technology Handbook" published by Nikkan Kogyo Shimbun (1939).
(March 30, 1987) P, 898-900) The same subject matter is also described in JP-A-80-73841.

In this way, forming a mixed layer between the adhesive layer on the metal foil side and the resin layer of the impregnating liquid-containing base material is considered important in terms of improving adhesive strength. Foil adhesion strength is still insufficient, and improving beer strength and solder heat resistance is still a major issue.

[Means for Solving the Problems] In order to solve the above problems, we conducted a detailed study on the structure of the adhesive layer between the metal foil and the resin-impregnated base material, and found that the structure of the adhesive layer is different from the presence of the mixed layer. The present invention was completed after realizing that it was necessary to meet specific requirements.

That is, the gist of the present invention is that a metal foil-clad laminate is composed of a laminate part, a metal foil part, and an adhesive layer part in between, and the laminate part is formed by impregnating a base material with a curable unsaturated resin and laminating the laminate part with a curable unsaturated resin. The adhesive layer part has a metal foil adhesive layer of at least 5 μs on the metal foil part side, and a mixture of the adhesive and a curable unsaturated resin on the laminate part side. There are layers in the metal foil laminate.

The contents of the present invention will be explained below.

Curable unsaturated resins referred to in the present invention include conventionally known resins having reactive unsaturated groups such as unsaturated polyester resins, epoxy acrylate resins, urethane acrylate resins, polyester acrylate resins, spiran resins, and diallyl phthalate resins. The side chain double bond type resins mentioned above are particularly preferably used, and these are usually liquid at room temperature.

The side chain double bond type resin referred to herein is a polymer composed of a main chain and a side chain, where the main chain is a backbone polymer containing a vinyl monomer unit having a functional group, and the side chain is a backbone polymer containing a vinyl monomer unit having a functional group. A branch having a radically reactive carbon-carbon double bond formed through a functional group of the chain, and the double bond of the branch is crosslinked with a crosslinking vinyl monomer. The vinyl monomer unit that constitutes the main chain of the side chain double bond type resin is a vinyl monomer unit that has a functional group as an essential unit, and includes vinyl monomer units that do not have a functional group as necessary. , these polymerize to form the main chain.

Monomers constituting the above essential units include acrylic acid,
Vinyl monomers having a carboxyl group as a functional group such as methacrylic acid, maleic anhydride, and maleic acid monoester, vinyl monomers having a glycidyl group as a functional group such as glycidyl methacrylate, glycidyl acrylate, etc. Allyl alcohol, 2-hydroxy Typical examples include vinyl monomers having a hydroxyl group as a functional group, such as ethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, and N-methylol acrylamide, especially acrylic acid and methacrylate. Acids are most preferably used.

In the present invention, the vinyl monomer unit having a functional group may be present as an active functional group when the main chain is formed by polymerization, or may be polymerized by reacting the side chain described below with the functional group of the monomer in advance. It refers to a type of vinyl monomer unit that has a functional group that serves to form a side chain into the main chain, regardless of whether the main chain is formed by forming a side chain.

Examples of vinyl monomers without functional groups include styrene,
α-methylstyrene, chlorostyrene, vinyltoluene, vinyl chloride, vinylidene chloride, vinyl bromide, acrylonitrile, ethylene, propylene, butadiene, acrylic ester, methacrylic ester, vinyl acetate, vinyl propionate, diester maleate, ethyl vinyl Examples include benzene.

The weight average molecular weight of the main chain composed of these vinyl monomer units is from 500 to 400,000, preferably from 10,000 to 200,000. This value is appropriately selected depending on the type of side chain. This molecular weight affects the physical properties of the laminate and impregnating properties, and
If it is less than 0, the mechanical properties of the cured laminate will be insufficient, and if it exceeds 400,000, the resin impregnation into the base material (paper etc.) will be poor, both of which are not preferred.

The amount of monomer units having functional groups in the main chain is related to the density of the side chains, and since it affects the curing reactivity between the side chains, an appropriate ratio is selected. .1
-2 mol is preferable, and 0.4-1.5 mol is more suitable.

The side chain referred to in the present invention refers to a chain having a >C-C double bond at the end or in the middle, and which forms a branch on the main chain via its functional group. As for things, (below the margins) 1 to work 0□Q ~ 0 ou-oco.

l 1
1 1
, ,
ヱ、工
EZ
Figure 0
0 1
Ql
1 CJ to 0
Engineering OI
country engineering u -0100-L) l u=o
l l,
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, ~ engineering
Q-Kan ×
Demand IQ
1
1 etc. can be exemplified as a general formula.

(I) In the formula, R1 to R3 are hydrogen or a methyl group, and n
represents an integer of 0 to 5, in the formula (II), R4 is hydrogen or a methyl group, and L and L2 are 10- or -N
H-, X and X2 represent a C to 01B hydrocarbon group or a hydrocarbon group connected by an ether bond, and in Xl and X, X and X2
The carbon atoms bonded to adjacent oxygens are primary or secondary carbons, and B is an aliphatic, alicyclic or aromatic hydrocarbon group up to C2o.

(m) In the formula, R5 is hydrogen or a methyl group.

Note that the side chains of the side chain double bond type resin according to the present invention are not limited to these, and any type of side chain that can form a crosslink between side chains by a radical reaction using a crosslinking vinyl monomer can be used.

Next, a manufacturing example of the side chain double bond type resin used in the present invention will be explained.

A method for producing a curable prepolymer for impregnation resin having a side chain represented by the general formula (1) in the main chain is as follows.

(1) First, a desired amount of (meth)acrylic acid (a component having a functional group) and an epoxy resin in an excess equivalent ratio to the (meth)acryloyl group are combined with a necessary reaction catalyst, such as a third
An unsaturated group-containing epoxy resin (A) containing a (meth)acryloyl group and an epoxy group in one molecule is produced by reacting a class amine, an amine salt, a quaternary ammonium salt, and a metal salt.

(11) Next, after adding the required type and amount of vinyl monomer (component without functional groups), the unsaturated group-containing epoxy resin (A) is prepared in the presence of an initiator such as azobisisobutyronitrile. By radically polymerizing the (meth)acryloyl group and the vinyl monomer, a reaction mixture containing a prepolymer having an epoxy group in the side chain can be obtained.

(iii) Furthermore, by adding the required amount of (meth)acrylic acid and causing the epoxy group remaining in the reaction mixture of (11) to react with the carboxyl group, vinyl unsaturation is added to the desired end of the side chain. A curable prepolymer having groups can be obtained.

Typical examples of the above epoxy resin include bisphenol A
There is a phenylglycidyl ether type polyaddition homolog synthesized from shrimp chlorohydrin and shrimp chlorohydrin. Its chemical structural formula is represented by, for example, the following general formula (IV).

R2 (■) In the formula, R1 and R2 are hydrogen or a methyl group, and n is 0
It is an integer of ~5.

Note that n is preferably 0 to 3.

When synthesizing an unsaturated group-containing epoxy resin, the ratio of (meth)acrylic acid to epoxy resin is 1 part (meth)acrylic acid
Per mole (i.e. per equivalent of carboxyl group),
It is necessary to use 1 mole or more of an epoxy resin having two or more glycidyl ether type epoxy groups in one molecule.

Still another method is to copolymerize a vinyl monomer that does not have a functional group with (meth)acrylic acid to form a main chain, and then convert the epoxy group in the unsaturated group-containing epoxy resin (A) into a functional group of the main chain. It is also possible to obtain a curable prepolymer having an unsaturated (meth)acryloyl group at the end of the side chain by carrying out an esterification reaction with a certain carboxyl group.

Examples of the method for producing a curable prepolymer for impregnation resin having a side chain represented by the general formula (n) in the main chain include the following.

(i) A main chain having a hydroxyl group as a functional group is synthesized by copolymerizing a (meth)acrylic monomer containing a hydroxyl group as one component and the above-mentioned vinyl monomer having no functional group.

(if) Separately, an unsaturated group-containing monoalcohol having a (meth)acryloyl group and a diisocyanate are mixed in a ratio of 1.2:1.
(molar ratio) to synthesize an unsaturated group-containing isocyanate that shares a free isocyanate group and a (meth)acryloyl group in one molecule of the reaction product.

(iii) The hydroxyl group-containing main chain obtained in (1) and (11) above is reacted with an unsaturated group-containing isocyanate in a crosslinking vinyl monomer or a solvent solution.

When a solvent is used, it is necessary to remove the solvent by any known method to obtain a prepolymer solution.

Examples of monomers having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate, which are the (meth)acrylic monomers mentioned above.
Representative examples include hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and methylol acrylamide.

For the polymerization in step (1), solution polymerization is convenient and can proceed to the next step as it is, but it is also possible to dissolve the polymer obtained by bar polymerization or bulk polymerization in monomer and use it for the next reaction. It's practical.

Typical commercially available diisocyanates include 2,4-tolylene diisocyanate,
2.4-Tolylene diisocyanate (80% by weight) and 2
, mixed isocyanates with 6-tolylene diisocyanate (20% by weight), diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,5-naphthylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated Examples include diphenylmethane diisocyanate and hydrogenated xylylene diisocyanate.

The reaction is carried out by dissolving the isocyanate in a solvent or a vinyl monomer for crosslinking, and adding the unsaturated group-containing alcohol dropwise.

When a solvent is used, it is usually necessary to replace the solvent with a crosslinking vinyl monomer, which is accomplished by fractional distillation taking advantage of the boiling point difference (the solvent has a lower boiling point). In the case of a vinyl monomer solution for crosslinking, it can be used as is.

Examples of the method for producing a curable prepolymer for impregnation resin having a side chain represented by the general formula (m) in the main chain include the following method.

(1) If the monomer does not have the above-mentioned functional group, the glycidyl (meth)acrylate is copolymerized with the glycidyl (meth)acrylate, and in the next step, the (meth)acrylic acid is substantially equimolar to the epoxy group contained in this copolymer resin. is added to cause the epoxy group to react with the carboxyl group.

(11) Still another method is to copolymerize a nyl monomer and (meth)acrylic acid that do not have the above-mentioned functional group, and in the next step, the mole is substantially equivalent to the carboxyl group contained in this copolymer resin. of glycidyl (meth)acrylate is added to cause the carboxyl group to react with the epoxy group.

For example, a styrenic monomer represented by the general formula (V) [wherein R6 represents hydrogen or a methyl group, and X3 represents a phenyl group, an alkylphenyl group, or a halogenated phenyl group] does not have the above-mentioned functional group. By using it as a vinyl monomer, a curable prepolymer of general formula (Vl) can be obtained.

OH( (Vl) In the formula, R6 and X3 have the same meanings as above, and R7 and R
8 represents hydrogen or a methyl group, and ml and nl represent positive integers.

The copolymerization, which is the first step in the production methods (1) and (11), can be carried out by solution polymerization, bar polymerization, etc., but in the case of solution polymerization, it is used as it is for the reaction in the next step. In the case of bar polymerization, the resulting copolymer is dissolved in a solvent or a crosslinking vinyl monomer before being used in the next reaction step.

Copolymerization of styrenic monomer and glycidyl monomer,
Alternatively, when copolymerizing styrenic monomers with methacrylic acid or acrylic acid, known radical polymerization catalysts,
For example, it can be easily carried out by using an organic peroxide, an azo compound, etc. and selecting an appropriate polymerization temperature.

In the present invention, the polymerization rate in the copolymerization step does not necessarily have to be 100%; for example, it is possible to stop at 80% and proceed to the next step while containing the residual monomer. This is one of the advantages of side chain double bond type resin.

That is, in the next step, the general formula (
(2) There is no damage to divinyl compounds having a diacryloyl structure or dimethacryloyl structure represented by the formula [wherein R and Rlo represent hydrogen or a methyl group].

Furthermore, it is obvious that the residual styrene monomer does not pose any problem in the present invention as will be described later.

Next, in the reaction of the second step, it is preferable to use an appropriate polymerization inhibitor, such as hydroquinone, in order to prevent polymerization of the residual styrene monomer and crosslinking reaction between the copolymer resins.

The amount of epoxy group or carboxyl group added and reacted with 1 equivalent of carboxyl group or epoxy group contained in the reaction of this second step is 0.9 to 1.1 equivalent, preferably 0.95 to 1,05 equivalent. It is.

As the crosslinked vinyl monomer used with the side chain double bond type resin referred to in the present invention, any known radically reactive vinyl monomer used in ml can be used, but styrene, α-methyl styrene, p
-Substituted styrenes such as methylstyrene, p-chlorostyrene, p-vinylstyrene; methyl niaacrylate, ethyl acrylate, butyl acrylate, acrylic acid-2-
Various (meth)acrylic acid esters such as ethylhexyl, methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate, and benzyl methacrylate: ethylene glycol diacrylate, ethylene glycol dimethacrylate, Vinyl polyfunctional (meth)acrylates such as acrylate, 4-butanediol dimethacrylate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate: polyurethane (
Vinyl polyfunctional oligoesters such as meth)acrylate and polyether (meth)acrylate are included.

Additionally, dibutyl maleate, dioctyl maleate, phenylmaleimides, vinyl acetate, vinyl propionate, divinylbenzene and its derivatives, diene compounds such as cyclopentadiene and butadiene, divinyl ester compounds, divinyl urethane compounds, etc. can also be used. can.

In particular, it is preferable to use a mixture of the above-mentioned monofunctional monomers and polyfunctional monomers as the vinyl monomer for crosslinking, since the heat resistance is further improved. The above-mentioned polyfunctional monomer must be a compound that can be copolymerized with the above-mentioned monofunctional monomer, and those that form a uniform copolymer are particularly preferred. The ratio of polyfunctional monomer to monofunctional monomer is preferably 5.
-50% by weight, more preferably 10-40% by weight.

The content of the side chain double bond type resin in the impregnating liquid according to the present invention is usually 10 to 60% by weight, and the crosslinking vinyl monomer can be contained up to 90% by weight. If the resin content is less than 10% by weight, the viscosity of the impregnating liquid becomes too low, resulting in poor moldability, lower crosslinking density, and a tendency for the punching properties, heat resistance, and solvent resistance of the metal foil-clad laminate to decrease. There is. Moreover, if it exceeds 60% by weight, the viscosity tends to increase too much and the impregnating property tends to decrease.

Flame retardancy is sometimes required for laminates, and in addition to additive flame retardants such as hexabromobenzene, it is not recommended to add reactive halogen-containing flame-retardant vinyl monomers in addition to cross-linking and vinyl monomers. In addition to flame retardant requirements, it is particularly preferred in terms of resin physical properties.

Preferably used halogen-containing flame-retardant monomers include monoglycidyl, an esterified product of a polyhydric alcohol and a saturated polybasic acid, which combine an aliphatic or alicyclic saturated hydrocarbon group containing bromine or chlorine with 1 to 18 carbon atoms. A halogen-containing flame-retardant monomer (1) obtained by addition reaction of methacrylate or monoglycidyl acrylate, general formula (■).

A bromine-containing flame-retardant monomer (2) represented by (IX).

(3) is mentioned.

OCHBr0 In the general formula, R1□, R1°, and R13 represent hydrogen or a methyl group.

The polyhydric alcohol used in the synthesis of the flame retardant monomer (1) is preferably an aliphatic or alicyclic alcohol having 1 to 12 carbon atoms, and an easily available example is dibroneopentyl glycol. Yes, but not limited to this.

Moreover, the flame-retardant monomers (2) and (3) can be synthesized by an esterification reaction between dibrome neopentyl glycol and (meth)acrylic acid. The type and addition ratio of these flame-retardant monomers are selected according to the requirements for flame-retardant electrical laminates, but it is preferable to add them to the impregnating liquid at a temperature of 5 to 70% by weight. If it is less than 5% by weight, no improvement in flame retardancy can be expected, and if it exceeds 70% by weight, physical properties other than flame retardancy will deteriorate, which is undesirable.

When producing a laminate using paper as a base material, if the halogen content in the impregnating liquid is approximately 10% or more in terms of bromine, the UL-94-V
- Passes the standard of 0. Note that it is even more effective when used in combination with 5b203.

As is known, aliphatic or alicyclic bromine compounds are not sufficiently thermally stable, and it is known that combined use with a stabilizer such as an epoxy compound is effective in improving heat resistance. On the other hand, it is said that chlorine provides about 1/2 the flame retardancy of bromine, and the inventors attempted to introduce a more stable chlorine compound into the resin composition, and found that the general formula ( chlorine-containing flame-retardant monomer (
4) was found to be effective.

[In the formula, R is hydrogen or a methyl group, and n2 is 1-1
Represents an integer of 0. ] This flame-retardant monomer (4) can be synthesized by ring-opening polymerization of epichlorohydrin using a boron trifluoride ether complex catalyst in the presence of acrylic acid or methacrylic acid. For this synthetic reaction, it is preferable that 12 not exceed 10.

In addition, the value of flame retardant effect is 0.45 when bromine is 1.
The value is ~0.50, which corresponds to the commonly said index.

In particular, this flame retardant monomer (4) is preferably used in combination with the above-mentioned flame retardant monomers (2) and/or (3), and is added in a total amount of 5 to 70% by weight in the impregnating liquid. It is preferable that If it is less than 5% by weight or more than 70% by weight, it is not preferred as in the case of flame retardant monomers (1) to (3).

These flame retardant monomers (1), (2), (3)
, (4) is reactive, so it does not migrate from the cured resin, and the viscosity of the impregnating liquid can be easily adjusted.
It becomes easy to set the molecular weight of the polymer having the side chain shown in II) and to select the type of vinyl monomer used for the main chain.

Another effect of the chlorine-containing flame-retardant monomer (4) is that since it is a polyether derivative, it imparts flexibility to the cured resin, thereby improving impact resistance.

Furthermore, for the purpose of improving impact resistance, a flexibility-imparting monomer represented by general formula (XI) may be added to the curable composition as a crosslinking vinyl monomer.

C0O-R16-o+COCH2CH2CH2CH2C
H2〇93R17(XI) ~C26 or a hydrocarbon group of C, R3 means a positive integer of 1 to I5. ] Such flexibility-imparting monomers are typically (meta)
After reacting acrylic acid with ethylene oxide, propylene oxide, or tetrahydrofuran, ε
- Obtained by addition reaction of caprolactone.

Specifically, examples thereof include an ε-caprolactone adduct of hydroquine ethyl (meth)acrylate, an ε-caprolactone adduct of hydroxy, dipropyl (meth)acrylate, and the like.

The flexibility-imparting monomer is used in an amount of 0.1 to 40% by weight based on the total amount of crosslinking vinyl monomers.

If it is less than 0.1% by weight, the impact resistance improvement effect is small;
When it exceeds 0% by weight, the rigidity decreases significantly.

The side chain double bond type resin composition according to the present invention can be cured using a general-purpose organic peroxide.

Further, known curing catalysts such as curing catalysts that are first sensitive to organic peroxides or alone or curing catalysts that are sensitive to radiation and electron beams can also be used.

The base material for impregnation in the present invention can be the same as the base material used for conventional laminates, such as glass fiber cloth, glass nonwoven fabric, etc., cellulose fibers such as kraft paper, linter paper, etc. refers to sheets or strips of inorganic fibers such as paper and asbestos cloth. In addition, from the viewpoint of impregnability and quality, paper yarns made mainly of cellulose fibers, such as kraft paper, whose density (bulk specific gravity) when air-dried is 0.3 to 0.1 g/cc are recommended. is preferred.

These substrates can be impregnated with a drying treatment using a treatment agent such as methylolmelamine, methylolphenol, methylolguanamine, or N-methylol compound before being impregnated with an impregnating liquid to improve their water resistance and reduce their hygroscopicity. This is preferable because electrical characteristics can be improved by doing so.

The thickness of the laminate of the present invention varies depending on the type of substrate, the composition of the curable resin, the use of the laminate, etc., but it is usually 0.5 to 3.0 mm thick. In addition, the ratio of cured resin in the laminate (cured resin)/(cured resin + base material) is 30 to 80% by weight.
is suitable.

Next, production examples of these side chain double bond type resins will be described.

Curable prepolymer 1-1 A separable flask (3000 ml) equipped with a stirrer, a thermometer with a gas inlet tube, a reflux condenser, and a dropping funnel.
), methacrylic acid (30 g, 0.41 mol), methyl ethyl ketone (400 g), styrene monomer (800 g,
g, 7.7 mol), azobisisobutyronitrile (5.0 g), and dodecyl mercaptan (12 g), and polymerization was carried out at 75 to 80° C. for 10 hours under a nitrogen atmosphere. Hydroquinone (0.5 g) was added to inhibit polymerization. The polymerization rate of styrene monomer was 76%, and the polymerization rate of methacrylic acid was 93%, and a polymer-containing liquid containing a styrene-methacrylic acid copolymer having a weight average molecular weight of about 50,000 was obtained.

In addition, another reactor with the same configuration as above was installed with "Epicoat 82".
7J (trade name of epoxy resin, manufactured by Yuka Shell Co., Ltd.)
(380 g, 1 mol), methacrylic acid (138 g.

1.6 mol), benzyldimethylamine (1.2 g),
Rose benzoquinone (0.12K) was charged and reacted at 120° C. for 3 hours under a nitrogen atmosphere. After the reaction, the acid value became almost zero, and a vinylation reagent containing an epoxy resin containing unsaturated groups was obtained. Add the entire polymer-containing solution prepared previously to the vinylation reagent, and add triphenylphosphine (5 g
) and rosebenzoquinone (0.1 Og) were added and heated, the methyl ethyl ketone solvent was distilled off at a boiling point of 110°C, and the mixture was reacted at the same temperature for 5 hours.

After the reaction, the unsaturated group-containing epoxy resin is about 1
It became 5%. Heat evaporation was continued at 30 to 50 mmHg while intermittently adding styrene monomer (too much g).Methyl ethyl ketone detected in the distillate was 0.
．． The operation was terminated when it became 1% or less.

The thus obtained resin liquid containing the curable prepolymer contains a side chain double bond type resin having the side chain represented by formula (I), has a nonvolatile content of 52% by weight, and has a viscosity of 6.2 poise (2
It was a yellowish brown liquid at a temperature of 5°C.

Curable prepolymer 1-2 A separable flask (5000 ml) equipped with a stirrer, a thermometer with a gas inlet tube, a reflux condenser, and a dropping funnel.
) were charged with methacrylic acid (35 g, 0.41 mol), ethyl acrylate (600 g, 6 mol), methyl ethyl ketone (600 g), and dodecyl mercaptan (6 g), and heated to 75° C. under a nitrogen atmosphere.

A solution of azobisisobutyronitrile (5 g) dissolved in 50 ml of methyl ethyl ketone was added from the dropping funnel so that the internal temperature was 80° C. or lower. It was made to react at 75-80 degreeC for 8 hours. Thereafter, the temperature was raised to 180°C, and methyl ethyl ketone and a very small amount of unreacted ethyl acrylate were distilled off. The resulting polymer weighed 631 g and had a weight average molecular weight of 70,000.

Another reactor (2000m1) with the same configuration as above
"Epicote 827J (trade name of epoxy resin, manufactured by Yuka Shell Co., Ltd.) (360 g, 1 mol), methacrylic acid (138 g, 1.6 mol), benzyldimethylamine (1.2 g), rosebenzoquinone (0.12 g)
) and reacted at 120° C. under nitrogen atmosphere for 3 hours.

The acid value of the reaction solution became almost zero, and a vinylation reagent containing an unsaturated group-containing epoxy resin was obtained.

Styrene monomer (1000 g) was added and dissolved in this vinylation reagent, and this was added to the polymer flask prepared previously. Plus triphenylphosphine (5g)
and rosebenzoquinone (G, fOg) and heated,
The reaction was carried out at 120°C for 4 hours.

After the reaction, the unsaturated group-containing epoxy resin is about 13
%Became.

The resin liquid containing the curable prepolymer thus obtained contains a side chain double bond type resin having the side chain represented by formula (I), has a nonvolatile content of 53% by weight, and has a viscosity of 8.9 poise (2
It was a yellowish brown liquid at a temperature of 5°C.

Curable prepolymer ll-1 It has a molecular weight of approximately 40,000, is composed of styrene and 2-hydroxyethyl methacrylate, and has a main chain (weight ratio of 82%) and 2-hydroxyethyl methacrylate.
- A curable prepolymer whose main component is a component consisting of side chains (8% by weight) consisting of hydroxypropyl methacrylate and tolylene diisocyanate (the remainder is unreacted and side-reacted components) (side chains represented by formula (II) above) [R in general formula (II) is a methyl group, Xl is -CH
2-CH2- Acrylic acid (72 g,
1 mol), ethyl acrylate (800 g, 8 mol), acrylonitrile (53 g, 1 mol), methyl ethyl ketone (700 g), dodecyl mercaptan (10 g
) and heated to 75°C under nitrogen atmosphere.

Azobisisobutyronitrile (5 g) was dissolved in methyl ethyl ketone (50 g), and this solution was added dropwise from the dropping funnel over about 1 hour to bring the temperature inside the reactor to 75-80°.
It was added while maintaining the temperature at C. After adding the catalyst, 8 hours at the same temperature.
The reaction continued for hours.

Next, the inside of the reactor was heated to 180° C. to distill off methyl ethyl ketone along with a small amount of unreacted monomer.

The amount of polymer obtained in the reactor (flask) was 920 g. The weight average molecular weight of this polymer was 40,000.

In this reactor, glycidyl methacrylate (142 g,
After adding parabenzoquinone (0.2 g) and triphenylphosphine (4 g), the mixture was reacted at 110° C. for 5 hours. Approximately 88% of glycidyl methacrylate was esterified. The resulting resin liquid containing the radically curable prepolymer was a yellowish brown liquid with a non-volatile content of 53% and a viscosity of 7.
The temperature was 1 poise (25°C).

Curable prepolymer m-2 Styrene (300 g), glycidyl methacrylate (45,4
g), benzoyl peroxide (3.5 g), and n-dodecyl mercaptan (3.5 g) were charged. Styrene (133 g), glycidyl methacrylate (45,4+r), benzoyl peroxide (1,8 g), n-dodecyl mercaptan (1
, 8 g) was added dropwise, and the mixture was further reacted at 115° C. for 1.5 hours. As a result, the reaction rate of styrene was 48%, the reaction rate of glycidyl methacrylate was 76%, and a colorless and transparent copolymer solution was obtained.

When acrylic acid (49.0 g) and hydroquinone (0.5 g) were added to this solution and reacted for 4 hours at 100°C, the reaction rate of acrylic acid was 90%, and a pale yellow transparent resin solution was obtained. . This includes a side chain double bond type resin having a side chain represented by the above formula (III).

Curable prepolymer m-3 Methyl ethyl ketone (199 g) as a solvent was placed in a Severa Puru flask (1000 ml) equipped with a stirrer, a thermometer with a gas inlet tube, a reflux condenser, and a dropping funnel, and then styrene (52.0 g, 0.5 mol), glycidyl methacrylate (14.2 g, 0.1 mol), benzoyl peroxide (0.52 g), and dodecyl mercaptan (0.52 g), and reacted at 85 to 90°C for 5 hours under nitrogen blowing. As a result, the polymerization rate of styrene was 62%, and the polymerization rate of glycidyl methacrylate was 73%. The solvent and unreacted monomers were removed using a rotary evaporator to obtain a white polymer.

A 45% solution of the above copolymer in styrene was added to the same apparatus as above, and then methacrylic acid (8,
4r), prepare hydroquinone (0.04g), 1
When the reaction was carried out at 00°C for 5 hours, the reaction rate of methacrylic acid was 94%.

This resin liquid contained a side chain double bond type resin having a side chain represented by the above formula (m), was pale yellow in color, and had a viscosity of 5.6 poise at 25°C.

"Vercure S A J (
Product name 1 Manufactured by NOF Corporation, peroxide catalyst, 1 part) and cobalt naphthenate (6% Co, 0.5 part) were added and a room temperature gelation test was conducted, gelation time was 13 minutes, the shortest. The curing time was 15.3 minutes, and the maximum exothermic temperature was 149°C.

Furthermore, the cured resin had the following physical properties and was excellent in transparency.

Tensile strength 6.5 kg/mA Bending strength 12.8 kg/mj Flexural modulus 314 kg/a+4 Heat deformation temperature 120°C Curable prepolymer m-4 The same equipment as used for producing curable prepolymer m-2 was used. Then, methyl ethyl ketone (199 g) was added as a solvent, and then styrene (52,0 g, 0.5 mol),
Methacrylic acid (17.2 g, 0.2 mol), benzoyl peroxide (0.52 g), and dodecyl methacrylic acid (CD, 52 g) were charged and reacted at 105 to 110°C for 4 hours under nitrogen blowing conditions. The polymerization rate of styrene was 65%, and the polymerization rate of methacrylic acid was 68%. Styrene was further added to this, and only methyl ethyl ketone was removed using a rotary evaporator to obtain a copolymer resin composition (copolymer content: 45%).

The above copolymer resin composition was added to the same apparatus as above, followed by glycidyl methacrylate (28.4 g).

0.2 mol) and hydroquinone (0.05 g) were reacted at 110-121)° C. for 3 hours, and the reaction rate of glycidyl methacrylate was 88%.

This includes a side chain double bond type resin having a side chain represented by the above formula (III).

Next, an example of manufacturing a flame retardant monomer that may be added to the resin liquid for impregnation will be described.

Flame retardant monomer (a) A separable flask (l) equipped with a dropping funnel and a stirrer
dibrome neopentyl glycol 38 in oooml)
After melting at 110° C., 185 g (1.25 mol) of phthalic anhydride and 1.0 g of p-toluenesulfonic acid were added.

20-20 (reacted for 4 hours at 170°C under a reduced pressure of 1 m + Hg. As a result, the acid value of the product was 40. Next, styrene monomer 140., glycidyl methacrylate 54 g (0.38 mol), hydroquinone 0.1
2g.

After adding 1.2 g of triethylamine, the mixture was reacted at 80° C. for 4 hours. As a result, the reaction rate of glycidyl methacrylate was 95%, and a flame retardant monomer solution with an acid value of 9 was obtained.

Flame-retardant monomer (b) In a separable flask (500 ml) equipped with a stirrer, dibrome neopentyl glycol (262 g).

1 mol), acrylic acid (108 g, 1.5 mol), 2.6 g of sulfuric acid and 0.05 g of rosebenzoquinone at 95°C.
The mixture was heated and stirred, and air was passed through the mixture at a rate of about 2 ONi/hour. The water produced by the esterification was discharged with a stream of air, accompanied by a small amount of acrylic acid. After 6 hours, a water slurry containing 6 g of barium carbonate was added, and the mixture was operated until all the water was distilled off, to obtain a dibrome-neopentyl glycol acrylic ester mixture.

Flame retardant monomer (e) Separable flask (1000ml) equipped with a stirrer
Acrylic acid (72 g, 1 mol) and 3 g of BF3/ether catalyst were charged into the flask, and epichlorohydrin (463 g, 5 mol) was added dropwise from the dropping funnel while the reaction temperature was maintained at 50° C. or lower to carry out the reaction.

The reaction was completed in 6 hours, so neutralize it with aqueous ammonia.
The aqueous phase was separated using a liquid separator, and then anhydrous sodium sulfate was added to dehydrate it.

Excess sodium sulfate and hydrated sodium sulfate were removed by filtering.

Two-door liquid at 30°C at a depth of 1cm, 1m+*Hg
The pressure was reduced to remove volatile components.

Next, the adhesive between the metal foil and the impregnated resin liquid-containing base material in the present invention will be described. Adhesives are also usually in liquid form before use.
For example, epoxy resin adhesives, polyisocyanate adhesives, epoxy acrylate adhesives, and unsaturated polyester resin adhesives are used, but epoxy resin adhesives in particular have excellent adhesive strength, heat resistance, and a stable partially cured state. It is preferable in terms of obtaining.

Copper foil, iron foil, aluminum foil, etc. can be used as the metal foil, but copper foil with a roughened adhesive surface is particularly preferred for electronic circuits.

In the present invention, the single layer of the metal foil adhesive on the metal foil side of the adhesive layer part is required to have a thickness of 5 or more.If the thickness is less than 5, the beer strength of the metal foil is This is because no improvement has been seen. The requirement for a mixed layer in addition to the single adhesive layer utilizes the conventional concept of improving adhesive strength, which is usually based on compatibility between different resins.

By the way, the reason why a single layer of adhesive of 5 layers or more is required is not only to contribute to the adhesive force with metal, which is the original function of the adhesive, but also to improve the adhesive strength between the laminate consisting of metal foil and resin-impregnated cured base material. This is thought to be due to the fact that it is able to exhibit a sufficient effect of stress relaxation between the different materials.

Incidentally, in order to sufficiently exhibit this stress relaxation, the adhesive needs to be highly flexible. For this purpose, in the case of epoxy resin adhesives, the epoxy compounds include dimer acid diglycidyl ether, polyalkylene oxide diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanesiol diglycidyl ether, bisphenol A alkylene Flexible epoxy resins such as diglycidyl ether of oxide adducts are used, or these are used as general-purpose bisphenol A.
Good to mix with mold epoxy resin.

In addition, as curing agents, polyoxypropylene diamine, polyamide amine, polysulfide, amino-terminated butadiene/nitrile rubber, carboxyl-terminated butadiene/nitrile rubber, etc.
Nitrile rubber or the like is used.

Also, even if the adhesive layer alone is made too large, the effect will not increase (,
A distance of 100 m or less is practical.

On the other hand, a layer in which the adhesive and the impregnated resin are in a compatible state is required between the adhesive layer and the resin-impregnated base material. This layer is especially necessary when both resins are of different types and prevents delamination.

Next, a method for manufacturing a metal foil-clad laminate having a structure according to the present invention will be explained.

When the metal foil is bonded to the laminate using an adhesive, the process is carried out, for example, as follows.

■Apply adhesive to the metal foil.

■The applied adhesive is heated and partially cured.

(2) On the other hand, a base material is impregnated with a curable unsaturated resin liquid, and a plurality of base materials impregnated with the resin liquid are laminated to form a liquid resin-impregnated laminate.

(2) Layer the partially cured adhesive-coated metal foil and the liquid resin-impregnated laminate, and heat and cure the adhesive and curable unsaturated resin.

A metal foil-clad laminate is formed in the manner described above.

Looking at the structure of the adhesive part at this time, there is a layer containing only the adhesive component in the adhesive layer part in contact with the metal foil, while a layer containing only the adhesive component exists in the part in contact with the laminate made of facilitative unsaturated resin. There is a mixed layer in which the sexually unsaturated resin components are mixed.

The method for forming a single layer of adhesive component with a thickness of 5μ or more, which is a requirement of the present invention, is as follows: 1. The adhesive is applied thicker and a mixed layer with the curable unsaturated resin component on the laminate side is formed. However, the thickness of the adhesive component alone layer should be 5 μm or more.

(2) By heat-treating the applied adhesive and partially curing it in advance, the formation of the mixed layer is limited to a limited range, and a single adhesive component layer with a thickness of 5 μm or more is ensured.

(2) First, the adhesive is applied to a thickness of 5 μm or more and partially cured by heating, and then the adhesive is applied again on top of the adhesive and bonded.

Among these methods, method (2) is the most desirable in terms of process and cost.

[Examples] 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.

Examples 1 to 3 Tsubo ff1135g/rr? kraft paper (Locm
10c111) was soaked in an aqueous solution of Nikaledin S-305j (trade name 9 manufactured by Nippon Carbide Co., Ltd., methylolmelamine), squeezed with a roller, and dried at 120°C for 30 minutes. This paper was placed in a flat plate and floated on an impregnating resin mixture having the composition shown in Table 1 to be impregnated with the liquid.

On the other hand, an electrolytic copper foil having a thickness of 35 μm was prepared, and an epoxy resin adhesive shown in Table 2 was applied thereto at a thickness of 3 hn+. Thereafter, heat treatment was performed at 100° C. for 6 minutes in a heat treatment apparatus to produce a partially cured adhesive-coated electrolytic copper foil.

Next, 6 sheets of paper containing the resin compound liquid and 1 sheet of copper foil with adhesive were stacked together, placed in a cellophane bag, sandwiched between 2 iron plates, and a pressure of 0.5 kg/c- was applied to the temperature at 120°C. It was cured for 1 hour at 100° C. and then for 10 hours at 100°C.

The resulting copper foil laminate had a thickness of 1.59 to 1.81 mm.

Table 3 shows the characteristic values of the laminate.

Table 1 Table 2 Example 4 Unsaturated polyester resin Propylene glycol (
long), isophthalic acid (83.2g:),
185℃3 while distilling condensed water under nitrogen blowing conditions.
Allowed time to react. Next, fumaric acid (87.2 g) was added and reacted at 185° C. for 6 hours. Finally, the inside of the system is about 10+a+
The pressure was reduced to sHg, 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 with a styrene concentration of 40%.

Manufacture of laminates Unsaturated polyester resin (75 parts), 2,3 maleic acid
-dibromopropyl (25 parts), antimony trioxide (4 parts)
part), organic peroxide catalyst "Perhexa 3M" (trade name 1 manufactured by NOF Corporation) (1 part), ε-caprolactone (8 mol) adduct of hydroxyethyl methacrylate (5 parts)
were sufficiently mixed to obtain a radically curable resin composition. A methylolmelamine-treated paper base material was impregnated with this resin composition, and five impregnated base materials were laminated.

Next, a sheet of electrolytic copper foil with adhesive similar to those in Examples 1 to 3 was stacked one on top of the other, placed in a cellophane bag, and sandwiched between two iron plates.
Apply a pressure of 5 kg/c- and heat at 120°C for 1 hour, then for another 1 hour.
It was cured at 00°C for 10 hours. The resulting laminate was 1.8
It was 1+us thick. Table 3 shows the characteristic values of the laminate.

Comparative Example A copper-clad laminate was obtained under the same conditions as in Example 1, except that the adhesive applied to the copper foil in Example 1 was not heat-treated. The resulting copper-clad laminate had a thickness of 1.59 mm. Table 3 shows the characteristic values of this product.

(Left below) Solder heat resistance and beer strength test method is JISC-648
According to 1. The thickness of the adhesive component alone is measured by mixing a dye into the curable unsaturated resin component and using a microscope.

[Effects] According to the present invention, a metal foil-clad laminate with improved solder heat resistance and beer strength can be obtained.

By using this metal foil-clad laminate, a printed circuit board with improved reliability can be obtained.

Claims (1)

[Claims] A metal foil-clad laminate is composed of a laminate part, a metal foil part, and an adhesive layer part in between, and the laminate part is made by impregnating a base material with a curable unsaturated resin, laminating it, and curing it. The adhesive layer part has a metal foil adhesive layer of at least 5 μm on the metal foil part side, and a mixed layer of the adhesive and a curable unsaturated resin on the laminate part side. A metal foil-clad laminate characterized by: