WO2009119247A1 - Metal-coated resin molded article, and process for production thereof - Google Patents

Abstract

Disclosed is a metal-coated resin molded article comprising a base and a metal coating film formed on the surface of the base. The base is produced by molding a resin composition comprising the components A, B and C shown below, wherein the component C is contained in an amount of 0.1 to 25 parts by mass relative to the total amount (100 parts by mass) of the components A and B. A: a first liquid crystalline polyester having a heat deflection temperature of 200°C or higher. B: a second liquid crystalline polyester having a lower heat deflection temperature than that of the first liquid crystalline polyester. C: an ethylene copolymer having an epoxy group (provided that the ethylene copolymer has an ethylene unit and an unsaturated carboxylic acid glycidyl ester unit and/or an unsaturated glycidyl ether unit in amounts of 50 to 99.9 mass% and 0.1 to 30 mass%, respectively, in the molecule.

Description

Metal-coated resin molded product and method for producing the same

The present invention relates to a metal-coated resin molded article using a substrate of a resin composition containing a liquid crystalline polyester, which is suitable for use in the electric and electronics industry, and a method for producing the same.

In recent years, liquid crystalline polyester has been widely used as a material for electronic parts or machine parts. For example, a circuit board obtained by forming a metal film on the surface of a substrate molded with a resin composition containing a liquid crystalline polyester has good moldability, dimensional stability, high elastic modulus and strength. It is also attracting attention as a substrate (MID) material.

However, since there is no strong chemical bond between the resin substrate and the metal coating, it is generally difficult to obtain high adhesion between the resin substrate and the metal coating. In particular, in the case of a circuit board, when the circuit board is subjected to a thermal load, there is a problem in that the adhesion of the metal film is lowered and peeling from the resin substrate occurs.

The resin substrate obtained by molding the liquid crystalline polyester resin composition also has a problem of adhesion with such a metal film. In order to improve this problem, the liquid crystalline polyester resin composition is molded to form a resin. There has been proposed a method in which a metal film is deposited by sputtering, ion plating, or vacuum deposition while the resin substrate is heated in a vacuum chamber so that the surface temperature is 60 ° C. or higher after the substrate is produced (Japanese Patent Laid-Open No. Hei 3). -8388). However, the effect of improving the adhesion cannot be sufficiently obtained by controlling only such a metal film deposition method.

Under such circumstances, the present applicant manufactured a substrate by molding a resin composition comprising a liquid crystalline polyester resin, an epoxy group-containing ethylene copolymer, and an inorganic filler, and a physical vapor deposition method was applied to the surface of the substrate. It has been found that a metal-coated resin molded product having a high degree of adhesion between the surface of the substrate and the metal film can be obtained by forming a metal film by (see JP-A-2005-290370).

As described above, the metal-coated resin molded product obtained by the invention of Patent Document 2 is a metal film formed with a high degree of adhesion, but a recent request to form a finer circuit with this metal film. In view of this, and from the viewpoint of further improving the manufacturing yield, further improvement of the adhesion of the metal film is required.

The present invention has been made in view of the above points, and an object of the present invention is to provide a metal-coated resin molded product capable of forming a metal film with higher adhesion and a method for producing the same.

The metal-coated resin molded product according to the present invention is:
A: First liquid crystalline polyester having a deflection temperature under 200 ° C. or higher B: Second liquid crystalline polyester having a deflection temperature lower than the deflection temperature under load of the first liquid crystalline polyester C: Ethylene copolymer containing an epoxy group Compound (however, the epoxy group-containing ethylene copolymer contains 50 to 99.9% by mass of ethylene units in the molecule, 0.1 to 30% by mass of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units) % Included)
A substrate obtained by molding a resin composition containing the above components A, B and C and having component C in the range of 0.1 to 25 parts by mass with respect to a total of 100 parts by mass of component A and component B And a metal film formed on the surface of the substrate. Here, the deflection temperature under load is defined as the deflection temperature under load determined by ASTM D648 (1988).

According to the present invention, the epoxy group-containing ethylene copolymer blended in the liquid crystalline polyester improves the toughness of the surface layer of the substrate, can improve the adhesion of the metal film to the substrate, and as the liquid crystalline polyester, By using together the first liquid crystalline polyester having a deflection temperature under load of 200 ° C. or more and the second liquid crystalline polyester having a deflection temperature under load that is lower than the deflection temperature under load of the first liquid crystalline polyester, While maintaining heat resistance with the liquid crystalline polyester, the second liquid crystalline polymer can enhance the adhesion of the metal film to the substrate, and can form a metal film with higher adhesion. is there.

Further, the present invention is characterized in that in the resin composition, the component B is 1 to 50% by mass with respect to the total amount of the component A and the component B.

According to the present invention, the effect of increasing the adhesion of the metal film to the substrate by the component B (second liquid crystalline polymer) is obtained more effectively while maintaining the heat resistance by the component A (first liquid crystalline polyester). It is something that can be done.

In addition, the present invention is characterized in that the component B is 30% by mass or less with respect to the total amount of the component A and the component B.

According to the present invention, the heat resistance by the component A (first liquid crystalline polyester) can be kept high, and it can be used particularly useful in applications requiring heat resistance.

In the present invention, the second liquid crystalline polyester is a divalent aromatic group linked by an ester bond. The divalent aromatic group includes a 1,2-phenylene group, 1,3, -It contains at least one kind of aromatic group selected from phenylene group and 2,3-naphthalene group, and the total amount of these aromatic groups is 10 to 45 mol% with respect to the total amount of divalent aromatic groups. It is characterized by this.

According to the present invention, the 1,2-phenylene group, 1,3-phenylene group, and 2,3-naphthalene group having a bent molecular structure, which is contained as a divalent aromatic group, can be used for the second liquid crystalline polyester. The deflection temperature under load can be adjusted to be low.

In the present invention, the epoxy group-containing ethylene copolymer contains 80 to 98% by mass of ethylene units and 2 to 15% by mass of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units in the molecule. It is characterized by this.

According to the present invention, it is possible to obtain a metal-coated molded article excellent in heat resistance by suppressing a decrease in heat resistance of the substrate due to the blending of the epoxy group-containing ethylene copolymer.

Further, the present invention is characterized in that the resin composition contains a fibrous inorganic filler having a diameter of 6 to 15 μm and an aspect ratio of 5 to 50 in addition to the components A to C.

According to the present invention, the strength of the substrate can be increased with the fibrous inorganic filler while ensuring adhesion with the metal coating.

The method for producing a metal-coated resin molded article according to the present invention includes a molding step of molding the resin composition to obtain a substrate, and a coating step of forming a metal film on the surface of the substrate. Is.

According to this invention, in the resin composition, the epoxy group-containing ethylene copolymer blended with the liquid crystalline polyester can form a substrate having improved surface layer toughness, thereby improving the adhesion of the metal coating to the substrate. The first liquid crystalline polyester having a deflection temperature under load of 200 ° C. or higher and the second liquid crystalline polyester having a deflection temperature lower than the deflection temperature under load of the first liquid crystalline polyester. In combination with the first liquid crystalline polyester, while maintaining heat resistance by the first liquid crystalline polyester, the second liquid crystalline polymer can enhance the adhesion of the metal film to the substrate, with a higher degree of adhesion. A metal film can be formed.

Further, the present invention is characterized by including a step of performing plasma treatment on the surface of the substrate before the coating step.

According to this invention, the surface of the substrate can be activated by plasma treatment, and the adhesion of the metal coating to the substrate surface can be further improved.

In the present invention, before the coating step, at a temperature of (Tm1-120) ° C. to (Tm1-20) ° C. [where Tm1 represents the flow start temperature (° C.) of the first liquid crystalline polyester]. And a step of heat-treating the substrate.

According to the present invention, this heat treatment can obtain the effect of lowering the dielectric loss tangent of the substrate in addition to the adhesion of the metal film, and can obtain a metal-coated resin molded product excellent in high-frequency characteristics and the like. It is.

In the present invention, the coating step is a step of forming a metal film on the surface of the substrate by a physical vapor deposition method.

According to the present invention, a metal film can be formed with high adhesion on the surface of a substrate by a physical vapor deposition method of a dry method.

Further, the present invention is characterized by including a step of forming a circuit pattern by applying laser patterning to the metal coating.

According to the present invention, by patterning by laser irradiation, it is possible to form a circuit by removing the metal coating other than the circuit portion without reducing the adhesion of the metal coating to the substrate, and to form a fine pattern circuit. It can be done easily.

As described above, according to the metal-coated resin molded product of the present invention, the epoxy group-containing ethylene copolymer blended with the liquid crystalline polyester improves the toughness of the surface layer of the substrate and improves the adhesion of the metal film to the substrate. The first liquid crystalline polyester having a deflection temperature under load of 200 ° C. or higher and the second liquid crystalline polyester having a deflection temperature lower than the deflection temperature under load of the first liquid crystalline polyester. In combination with the first liquid crystalline polyester, while maintaining heat resistance by the first liquid crystalline polyester, the second liquid crystalline polymer can enhance the adhesion of the metal film to the substrate, with a higher degree of adhesion. A metal film can be formed.

The metal-coated resin molded product can form a fine circuit pattern with a metal film having high adhesion, and can be used particularly effectively in the electric and electronic industries, particularly in fields where high frequency characteristics are required. Is.

(A) is a graph which shows the relationship between the content rate of 2nd liquid crystalline polyester, and peel strength, (b) is a graph which shows the relationship between the content rate of 2nd liquid crystalline polyester, and thermal deformation temperature.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, modes for carrying out the present invention will be described.

The substrate used in the present invention is obtained by molding a resin composition containing the components A, B and C as essential components. First, the liquid crystalline polyester according to Component A and Component B will be described.

Here, the liquid crystalline polyester is a polyester capable of forming a melt phase having optical anisotropy, and from the viewpoint of obtaining a substrate having high heat resistance, the polymer main chain is composed of an aromatic group, A polyester in which these aromatic groups are linked by an ester bond (—C (O) O— or —OC (O) —) is preferable. The aromatic group includes a monocyclic aromatic group and a condensed ring aromatic group, a group in which a monocyclic aromatic group or a condensed ring aromatic group is connected by a direct bond, an oxygen atom, a sulfur atom, It is a concept including a group linked through a linking group selected from an alkylene group having 6 to 6 carbon atoms, a sulfonyl group, and a carbonyl group.

The first liquid crystalline polyester as component A has a deflection temperature under load of 200 ° C. or higher, and the second liquid crystalline polyester as component B has a load lower than the deflection temperature under load of the first liquid crystalline polyester. It has a deflection temperature. That is, in the combination of the first liquid crystalline polyester and the second liquid crystalline polyester, the deflection temperature under load of the first liquid crystalline polyester is Tb1 (° C.), and the deflection temperature under load of the second liquid crystalline polyester is Tb 2 (° C. ) Is selected to satisfy the following formula.

Tb1 ≧ 200 ° C
Tb1> Tb2
The deflection temperature under load of the liquid crystalline polyester can be controlled by a method for controlling the molecular weight of the liquid crystalline polyester, a method for changing the combination of monomer units constituting the liquid crystalline polyester, and the like. It is possible to obtain a liquid crystalline polyester having a desired deflection temperature under load. Details regarding a method for producing such a liquid crystalline polyester with controlled deflection temperature under load will be described later.

As described above, the deflection temperature under load (Tb1) of the first liquid crystalline polyester is 200 ° C. or higher, more preferably 230 ° C. or higher, and further preferably 240 ° C. or higher. When the deflection temperature under load (Tb1) of the first liquid crystalline polyester is lower than 200 ° C., thermal deformation of the substrate obtained by molding the resin composition becomes large, and a metal-coated resin molded product having a desired size can be obtained. May be difficult. The upper limit of the deflection temperature under load (Tb1) of the first liquid crystalline polyester is not particularly specified, but practically about 300 ° C. is the upper limit.

Further, as described above, the deflection temperature under load (Tb2) of the second liquid crystalline polyester is lower than the deflection temperature under load (Tb1) of the first liquid crystalline polyester, and the deflection temperature under load (Tb2) is the first. Although it is selected according to the deflection temperature under load (Tb1) of the liquid crystalline polyester, the deflection temperature under load (Tb2) is preferably 190 ° C. or less, and more preferably 150 ° C. or less. If the deflection temperature under load (Tb2) of the second liquid crystalline polyester exceeds 190 ° C., the effect of improving the adhesion of the metal film may not be sufficiently obtained. The lower limit of the deflection temperature under load (Tb2) of the second liquid crystalline polyester is not particularly specified, but practically about 100 ° C. is the lower limit.

As described above, the first liquid crystal polyester having a high load deflection temperature (Tb1) is used in combination with the second liquid crystal polyester having a low load deflection temperature (Tb2). The second liquid crystalline polyester having a low load deflection temperature (Tb2) while securing heat resistance can be molded with the liquid crystalline polyester, and the substrate having improved adhesion to the metal film can be formed. The difference between the deflection temperatures under load between the liquid crystalline polyester and the second liquid crystalline polyester (Tb1−Tb2) is preferably 50 ° C. or higher, and more preferably 80 ° C. or higher.

Next, what is suitable as 1st liquid crystalline polyester and 2nd liquid crystalline polyester is demonstrated. As these liquid crystalline polyesters, for example,
(1) Obtained by polymerizing a combination of monomers composed of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol. (2) Using different types of aromatic hydroxycarboxylic acids as monomers, polymerizing them. What can be obtained (3) The thing obtained by superposing | polymerizing combining the monomer which consists of aromatic dicarboxylic acid and aromatic diol can be mentioned.

In addition, it is also possible to produce a liquid crystalline polyester by using these ester-forming derivatives instead of the above aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid and aromatic diol. It is preferable to use a formable derivative because the liquid crystalline polyester can be more easily produced.

Among the above (1) to (3), the liquid crystalline polyester obtained by (1) is more preferable. As a means for producing such a liquid crystalline polyester, an acyl group of an acylated product obtained by acylating a phenolic hydroxyl group of an aromatic diol and an aromatic hydroxycarboxylic acid with a fatty acid anhydride, an aromatic dicarboxylic acid and an aromatic There is a method in which a carboxyl group of a hydroxycarboxylic acid acylated product is polymerized so as to cause a transesterification reaction, and more preferably, a first polyester that obtains a relatively low molecular weight polyester mainly by a transesterification reaction between monomers and a polycondensation reaction A stage (sometimes referred to as “first stage polymerization”) and a second stage (sometimes referred to as “second stage polymerization”) in which the low molecular weight polyesters are bonded together to increase the molecular weight. It is a polymerization process in stages. Such a polymerization method has an advantage that it is easy to control the molecular weight of the obtained liquid crystalline polyester.

Examples of the fatty acid anhydride include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, and trichloroanhydride. Use acetic acid, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, β-bromopropionic anhydride Can do. These may be used individually by 1 type, and may mix and use 2 or more types. Among these, acetic anhydride, propionic anhydride, butyric anhydride, and isobutyric anhydride are preferable in terms of price and handleability, and acetic anhydride is more preferable.

In the polymerization reaction of liquid crystalline polyester, it is preferable to use an imidazole compound represented by the following formula (C1) as a catalyst. Such a polymerization reaction in the presence of an imidazole compound is suitable for producing a liquid crystalline polyester, and has an advantage that the polymerization time is shortened and the resulting polyester is not significantly colored.

(In the formula (C1), R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a cyano group, a cyanoalkyl group having 1 to 4 carbon atoms, 4 represents a group selected from a cyanoalkoxy group, a carboxyl group, an amino group, an aminoalkyl group having 1 to 4 carbon atoms, an aminoalkoxy group having 1 to 4 carbon atoms, a phenyl group, a benzyl group, a phenylpropyl group, and a formyl group. .)
Specific examples of the imidazole compound represented by the formula (C1) include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 4-ethyl. Imidazole, 1,2 dimethylimidazole, 1,4-dimethylimidazole, 2,4-dimethylimidazole, 1-methyl-2-ethylimidazole, 1-methyl-4-ethylimidazole, 1-ethyl-2-methylimidazole, 1 -Ethyl-2-ethylimidazole, 1-ethyl-2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1-benzyl-2-methyl Imidazole, 2-pheny 4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 4-cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole, etc. These can be used alone or in combination of two or more. Particularly preferred imidazole compounds are those in which R ₁ is an alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ and R ₄ are all hydrogen atoms. In particular, use of 1-methylimidazole and / or 2-methylimidazole is preferable from the viewpoint of availability.

In the transesterification / polycondensation reaction, the molecular weight of the resulting liquid crystalline polyester can be controlled by the equivalent ratio of the acyl group of the acylated product to the carboxyl group of the aromatic dicarboxylic acid and / or aromatic hydroxycarboxylic acid. In order to obtain a liquid crystalline polyester having a practical molecular weight, the acyl group equivalent number of the acylated product subjected to the polymerization reaction and the carboxyl group equivalent number of the aromatic dicarboxylic acid and / or aromatic hydroxycarboxylic acid are [ The ratio is preferably set to 0.8 to 1.2, expressed as [acyl group equivalent number] / [carboxyl group equivalent number].

As mentioned above, the polymerization reaction of the liquid crystalline polyester is preferably carried out in two stages. In the first stage polymerization (mainly the stage in which the transesterification proceeds), the polymerization temperature is 250 to 400 ° C., preferably 150 to 350. It is preferable to carry out in the range of ° C. When the acylation reaction and the first stage polymerization are carried out in the same reactor, the temperature may be raised from the reaction temperature of the acylation reaction to the reaction temperature of the first stage polymerization. The heating rate is preferably 0.5 to 50 ° C./min, more preferably 1 to 10 ° C./min.

As the acylated product, an aromatic diol and / or aromatic hydroxycarboxylic acid that has been acylated in advance may be used as a starting material before polymerization. However, from the viewpoint of availability of raw materials, use an acylated product obtained by acylating the phenolic hydroxyl group of aromatic diol and aromatic hydroxycarboxylic acid with fatty acid anhydride in the same reactor as the polymerization reaction. Is preferred.

In this case, the amount of the fatty acid anhydride in obtaining the acylated product is preferably 1.0 to 1.2 equivalent times the total number of equivalents of the phenolic hydroxyl group of the aromatic diol and aromatic hydroxycarboxylic acid. 1.05-1.1 equivalent times is more preferable. When the amount of the fatty acid anhydride is less than 1.0 in terms of the number of equivalents of the phenolic hydroxyl group, the raw material may be sublimated during polymerization to a liquid crystalline polyester due to a shift in equilibrium during acylation, and the reaction system Is prone to obstruction. On the other hand, when the amount of the fatty acid anhydride exceeds 1.2 times in terms of the number of equivalents of the phenolic hydroxyl group, coloring of the obtained liquid crystalline polyester may be a problem. The conditions for the acylation reaction to obtain an acylated product are 130 to 180 ° C. and 30 minutes to 20 hours, more preferably 140 to 160 ° C. and 1 to 5 hours.

In order to accelerate the transesterification reaction between the acyl group and the carboxyl group by utilizing the deviation of equilibrium, it is preferable to evaporate and remove the by-product fatty acid and the unreacted fatty acid anhydride from the reaction system. When part of the distilled fatty acid is refluxed to the reactor, the raw material components evaporated or sublimated can be returned to the reactor together with the refluxed fatty acid by condensation or reverse sublimation.

Next to the first stage polymerization, the second stage polymerization is performed. The polymer having a relatively low molecular weight (hereinafter referred to as “prepolymer”) obtained by the first stage polymerization is cooled, preferably cooled to about room temperature to form a solid, and then the obtained solid is pulverized. Etc. to be processed into powder such as powder or flake. Here, “powder” means a powder having an average particle diameter of 1 mm or less, preferably a powder having an average particle diameter of 0.1 to 1 mm. In the second stage polymerization, the prepolymer thus processed into a powder is polymerized at a polymerization temperature of 200 to 350 ° C. The second stage polymerization may be carried out while raising the temperature stepwise. Specifically, the temperature is raised in about 0.5 to 2 hours to a temperature lower than the polymerization temperature in the first stage polymerization. Then, after raising the temperature to the final polymerization temperature (200 to 350 ° C.) over 1 to 10 hours, polymerization is carried out while maintaining the final polymerization temperature. If it does in this way, a prepolymer will become high molecular weight and liquid crystalline polyester will be formed. The molecular weight of the obtained liquid crystalline polyester can be controlled by the polymerization conditions of the second stage polymerization, and a liquid crystalline polyester having a desired molecular weight can be produced by controlling the polymerization conditions.

As described above, the first stage polymerization is carried out by melt polymerization and the second stage polymerization is carried out by solid phase polymerization. In general, the higher the molecular weight of the liquid crystalline polyester, the higher the deflection temperature under load tends to increase. When the first liquid crystalline polyester and the second liquid crystalline polyester to be applied to the present invention are produced, liquid crystallinity having a desired load deflection temperature depending on the polymerization conditions of the second stage polymerization which is solid phase polymerization. Polyester can be obtained.

Moreover, in the said polymerization reaction, when adding the imidazole compound represented by Formula (C1) described as a suitable catalyst, the addition amount is the aromatic dicarboxylic acid, aromatic diol, and aromatic hydroxy which were used for polymerization reaction. When the total mass of the carboxylic acid is 100 parts by mass, it is preferably 0.005 to 1 part by mass. From the viewpoint of color tone and productivity of the obtained liquid crystalline polyester, the addition amount is more preferably 0.05 to 0.5 parts by mass. When the addition amount is within this range, the polymerization reaction of the liquid crystalline polyester becomes easier, and the adhesion between the surface of the substrate and the metal film is further improved when obtaining a metal film resin molded product to be described later. can do. The reason why such an effect of improving adhesion is manifested is not necessarily clear, but is based on the inventors' original knowledge. The timing of addition of the imidazole compound is not a condition that the imidazole compound is present in the reaction system at the time of transesterification, and it may be charged simultaneously with various monomers constituting the liquid crystalline polyester and polymerized. It may be a method of charging in a stage, or a method of charging between the first stage polymerization and the second stage polymerization.

In the polymerization reaction for obtaining a liquid crystalline polyester as described above, the imidazole compound is particularly useful as a catalyst, but other catalysts may be used as necessary. Other catalysts include germanium compounds such as germanium oxide, stannous oxalate, stannous acetate, dialkyl tin oxide, tin compounds such as diaryl tin oxide, titanium dioxide, titanium alkoxide, alkoxy titanium silicates. Titanium compounds such as antimony compounds such as antimony trioxide, metal salts of organic acids such as sodium acetate, potassium acetate, calcium acetate, zinc acetate, ferrous acetate, boron trifluoride and aluminum chloride Examples include inorganic acids such as Lewis acids, amines, amides, hydrochloric acid, sulfuric acid and the like. However, if a catalyst containing a metal component is used as a catalyst for the polymerization method for obtaining a liquid crystalline polyester, the electrical properties of the resulting substrate may be impaired. It is preferable to determine the type and amount of use in consideration of the characteristics of the substrate.

As described above, in the method for producing a liquid crystalline polyester, adjustment of the equivalent ratio of the acyl group of the acylated product and the carboxyl group of the aromatic dicarboxylic acid and / or aromatic hydroxycarboxylic acid, adjustment of the polymerization conditions, addition of a catalyst, etc. Thus, the molecular weight of the obtained liquid crystalline polyester can be controlled, and the deflection temperature under load of the obtained liquid crystalline polyester can be appropriately adjusted. In the case of obtaining a desired load deflection temperature by controlling the molecular weight of the liquid crystalline polyester, from the viewpoint of the heat resistance of the obtained substrate, the molecular weight is in the range of 10,000 to 50,000 in terms of weight average molecular weight. Is preferred.

In the liquid crystalline polyester of the present invention, as a means of controlling the deflection temperature under load, in addition to the adjustment of the molecular weight as described above, the deflection unit temperature is controlled by optimizing various monomer units constituting the liquid crystalline polyester. It is also useful to do so. Hereinafter, each monomer of the above-mentioned aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, and aromatic diol will be described.

Examples of the aromatic diol include 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, methylhydroquinone, chlorohydroquinone, acetoxyhydroquinone, nitrohydroquinone, catechol, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1, 6-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3 , 5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4 -Hydroxy-3- Lorophenyl) propane, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-3,5-dichlorophenyl) methane, bis- (4-hydroxy) -3,5-dibromophenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, bis- (4-hydroxy-3-chlorophenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, Bis- (4-hydroxyphenyl) ketone, bis- (4hydroxy-3,5-dimethylphenyl) ketone, bis- (4-hydroxy-3,5-dichlorophenyl) ketone, bis- (4-hydroxyphenyl) sulfide, Mention may be made of bis- (4hydroxyphenyl) sulfone. An aromatic diol selected from these may be used alone, or two or more kinds may be used in combination. Among these, the use of 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, and bis- (4hydroxyphenyl) sulfone is available. It is preferable in terms of easiness.

Examples of the aromatic hydroxycarboxylic acid include parahydroxybenzoic acid, metahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-3-naphthoic acid, 1-hydroxy-4-naphthoic acid, 3-hydroxy Hydroxy-2-naphthoic acid, 4-hydroxy-4′-carboxydiphenyl ether, 2,6-dichloro-parahydroxybenzoic acid, 2-chloro-parahydroxybenzoic acid, 2,6-difluoro-parahydroxybenzoic acid, 4- Mention may be made of hydroxy-4'-biphenylcarboxylic acid. Aromatic hydroxycarboxylic acids selected from these may be used alone or in combination of two or more. Among these, the use of parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid is preferable from the viewpoint of easy availability.

In the first liquid crystalline polyester and the second liquid crystalline polyester, from the viewpoint of obtaining practical liquid crystallinity, a monomer unit represented by the following formula (2), derived from parahydroxybenzoic acid, It is preferable to contain at least 30 mol% with respect to the total of monomer units constituting the liquid crystalline polyester.

Further, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. Acid, methyl terephthalic acid, methyl isophthalic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl sulfone-4,4'-dicarboxylic acid, diphenyl ketone-4,4'-dicarboxylic acid, 2,2'-diphenylpropane- Mention may be made of 4,4′-dicarboxylic acid. Aromatic dicarboxylic acids selected from these may be used alone or in combination of two or more. Of these, use of terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid is preferable from the viewpoint of availability.

The monomers applied to the first liquid crystalline polyester of component A in the present invention include 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) An aromatic diol selected from propane and bis- (4-hydroxyphenyl) sulfone, an aromatic hydroxycarboxylic acid selected from parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid, terephthalic acid, isophthalic acid, 2, A combination using an aromatic dicarboxylic acid selected from 6-naphthalenedicarboxylic acid is preferable from the viewpoint of easy availability of raw materials.

In particular, the first liquid crystalline polyester includes 30 to 80 mol% of monomer units derived from aromatic hydroxycarboxylic acid and 10 to 35 mol of monomer units derived from aromatic diol based on the total of all monomer units. %, And those having 10 to 35 mol% of monomer units derived from aromatic dicarboxylic acid are preferred. The first liquid crystalline polyester composed of such monomer units is likely to have a deflection temperature under load of 200 ° C. or higher as described above. Such a first liquid crystalline polyester is prepared by blending each monomer in these proportions. Can be obtained by polymerization.

The first liquid crystalline polyester preferably has a flow start temperature of 270 ° C. or higher. When the flow start temperature of the first liquid crystalline polyester is 270 ° C. or higher, a substrate having good heat resistance can be obtained. The upper limit of the flow start temperature is not particularly set, but practically about 350 ° C. is the upper limit.

This flow start temperature is obtained by the following method. The following flow initiation temperature measurement method is an index representing the molecular weight of liquid crystalline polyesters well known in the art (for example, Naoyuki Koide, “Liquid Crystal Polymer—Synthesis / Molding / Application—”, pages 95 to 105). CMC, published June 5, 1987).

(Flow start temperature measurement method)
Using a capillary rheometer having a nozzle with an inner diameter of 1 mm and a length of 10 mm, the melt viscosity is increased when the heated melt is extruded from the nozzle at a heating rate of 4 ° C./min under a load of 980 N / cm ² (100 kgf / cm ² ). Is measured at 48000 poise, and this is taken as the flow start temperature. A related standard in JIS is JIS K6719 (1977).

In order to reduce the deflection temperature under load of the liquid crystalline polyester, it is effective to introduce a monomer unit that reduces the rigidity of the liquid crystalline polyester. Here, reducing the rigidity of the liquid crystalline polyester means introducing a monomer unit that imparts flexibility to the main chain of the liquid crystalline polyester (hereinafter referred to as “flexible monomer unit”). By imparting flexibility to the main chain, the deflection temperature under load can be reduced. Specific examples of the flexible monomer include a monomer unit having a 1,2-phenylene group skeleton, a monomer unit having a 1,3-phenylene group skeleton, and a monomer unit having a 2,3-naphthalene group skeleton. Preferred monomer units having a 1,3-phenylene group skeleton are monomer units derived from resorcin or isophthalic acid, and preferred monomer units having a 1,2-phenylene group skeleton are monomers derived from catechol and phthalic acid. Preferred monomer units having a 2,3-naphthalene group skeleton are 2,3-dihydroxynaphthalene, 2,3-naphthalenedicarboxylic acid, 2-hydroxy-3-naphthoic acid, and 3-hydroxy-2-naphthoic acid. Thus, the flexible monomer unit is preferably an aromatic diol, an aromatic dicarboxylic acid, or an aromatic hydroxycarboxylic acid.

At this time, the first liquid crystal polyester has a tendency that, as the number of flexible monomer units in the monomer units constituting the liquid crystal polymer is smaller, a higher deflection temperature under load of 200 ° C. tends to be obtained. The flexible monomer unit is preferably less than 10 mol%, more preferably 8 mol% or less, and particularly preferably 6 mol% or less with respect to the total of the monomer units constituting the flexible polyester.

On the other hand, with respect to the second liquid crystalline polyester, the deflection temperature under load of the second liquid crystalline polyester is increased by making the content of the flexible monomer unit higher than that of the first liquid crystalline polyester. The deflection temperature under load can be made lower. Specifically, the flexible monomer unit is preferably 10 mol% or more, more preferably 12.5 mol% or more, based on the total of the monomer units constituting the second liquid crystalline polyester. It is particularly preferably 15 mol% or more. However, from the viewpoint of ensuring the practical heat resistance of the second liquid crystalline polyester, the flexible monomer unit is preferably 45 mol% or less with respect to the total of the monomer units constituting the second liquid crystalline polyester, 40 mol% or less is more preferable.

As described above, the first liquid crystalline polyester constituting the component A applied to the present invention and the second liquid crystalline polyester constituting the component B are monomer units constituting the molecular weight control of the liquid crystalline polyester and the liquid crystalline polyester. Can be obtained in various combinations.

In the resin composition used in the present invention, the content ratio of the first liquid crystalline polyester of component A and the second liquid crystalline polyester of component B blended as liquid crystalline polyester is 100% of the total mass of component A and component B. When the content is mass%, the component B is preferably 1 to 50 mass%. In addition, with respect to a base obtained from the resin composition of the present invention and a metal-coated resin molded article obtained by coating a base with a metal coating, from the viewpoint of maintaining a higher level of mechanical strength and heat resistance, component B is more preferably 1 It is in the range of ˜30% by mass. For example, when molding a substrate that can withstand 250 ° C. reflow, component B is preferably set in the range of 1 to 30% by mass.

Next, the epoxy group-containing ethylene copolymer which is component C of the resin composition used in the present invention will be described.

The epoxy group-containing ethylene copolymer of Component C contains 50 to 99.9% by mass of ethylene units, 0.1 to 30% by mass of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units in the molecule. % Is included. In particular, in order to obtain excellent heat resistance and toughness of the substrate obtained from the resin composition, and to further enhance the adhesion to the metal film, the epoxy group-containing ethylene copolymer contains ethylene units in the molecule. It is more preferable to contain 80 to 98% by mass of the unsaturated glycidyl ester unit and / or 2 to 15% by mass of the unsaturated glycidyl ether unit. In addition to these units, an ethylenically unsaturated ester unit may be included as necessary. In this case, the amount of the ethylenically unsaturated ester unit is preferably less than 50% by mass.

As the compound giving the unsaturated carboxylic acid glycidyl ester unit or the unsaturated glycidyl ether unit, those represented by the following formulas (3) and (4) can be used.

(In the formula (3), R is a hydrocarbon group having 2 to 13 carbon atoms having an ethylenically unsaturated bond.)

(In the formula (4), R has the same meaning as the formula (3), and X is any of the following.)

Specifically, examples of the compound represented by the formula (3) include glycidyl acrylate, glycidyl methacrylate, and itaconic acid glycidyl ester. Examples of the compound represented by the formula (4) include allyl glycidyl ether, 2-methylallyl. Examples thereof include glycidyl ether and styrene p-glycidyl ether.

Examples of the compound that derives the ethylenically unsaturated ester unit include vinyl acetate, vinyl propionate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Examples include carboxylic acid vinyl esters and α, β-unsaturated carboxylic acid alkyl esters. When introducing an ethylenically unsaturated ester unit into an epoxy group-containing ethylene copolymer, among these examples, vinyl acetate, methyl acrylate, and ethyl acrylate are particularly preferable.

In addition, as an epoxy group-containing ethylene copolymer of component C, a binary or ternary copolymer comprising ethylene, an unsaturated carboxylic acid glycidyl ester and / or an unsaturated glycidyl ether, or an ethylene-based unsaturated copolymer as an optional monomer. A ternary or higher multicomponent copolymer obtained by copolymerization of a saturated ester can be used.

The epoxy group-containing ethylene copolymer is usually a compound that gives an ethylene unit, a compound that gives an unsaturated carboxylic acid glycidyl ester unit and / or an unsaturated glycidyl ether unit, and, if necessary, an ethylene-based unsaturated copolymer. A compound that gives a saturated ester unit can be produced by a method of copolymerization in the presence of a radical generator under the conditions of 50.7 to 405.3 MPa (500 to 4000 atm) and 100 to 300 ° C. Such copolymerization reaction may be performed in the presence of a suitable solvent or chain transfer agent.

Preferred examples of the epoxy group-containing ethylene copolymer include a copolymer composed of units derived from ethylene units and glycidyl methacrylate, a unit derived from ethylene units and glycidyl methacrylate, and a unit derived from glycidyl methyl acrylate. Copolymer, copolymer consisting of units derived from ethylene units and glycidyl methacrylate and units derived from glycidyl ethyl acrylate, or unit derived from ethylene units and glycidyl methacrylate and units derived from vinyl acetate It is a copolymer. In particular, a copolymer comprising an ethylene unit and a unit derived from glycidyl methacrylate is preferred as the epoxy group-containing ethylene copolymer of Component C.

The epoxy group-containing ethylene copolymer preferably has a melt index (MFR: JIS K7210, measurement conditions: 190 ° C., 2.16 kg load) in the range of 0.5 to 100 g / 10 min, more preferably 2 to 50 g / 10 min. A substrate obtained from a resin composition containing an epoxy group-containing ethylene copolymer having a melt index within this range provides good mechanical properties, and also contains component A and component B liquid crystalline polyesters and an epoxy group. High compatibility with the ethylene copolymer is obtained.

In the resin composition used in the present invention, the content of the epoxy group-containing ethylene copolymer of component C is 0.1 to 25 parts by mass when the total mass of liquid crystalline polyesters of component A and component B is 100 parts by mass. The range of 10 to 20 parts by mass is more preferable. If the content of the epoxy group-containing ethylene copolymer is less than 0.1 parts by mass, the effect of improving the adhesion of the metal film to the substrate to be molded cannot be obtained. Moreover, when content exceeds 25 mass parts, while the heat resistance of a base | substrate will deteriorate, the moldability of a resin composition will fall remarkably.

In the resin composition applied to the present invention, an inorganic filler may be added as necessary from the viewpoint of improving the mechanical strength of the obtained substrate. For example, when a fibrous inorganic filler such as glass fiber or carbon fiber is added to the resin composition, the blending amount of the fibrous inorganic filler is 100 parts by mass of the total mass of component A and component B liquid crystalline polyester. Then, it is preferably set in the range of 5 to 500 parts by mass. When the blending amount of the fibrous inorganic filler is within this range, the mechanical strength of the substrate can be increased without reducing the adhesion between the substrate and the metal coating. Generation of cracks in the line region can be effectively prevented.

Regarding the shape of the fibrous inorganic filler, the fiber diameter is preferably in the range of 6 to 15 μm, and the aspect ratio is preferably in the range of 5 to 50. When the fiber diameter is less than 6 μm, the inorganic filler is easily damaged when the inorganic filler is dispersed in the resin composition or when the substrate is molded, and the inorganic filler is uniformly dispersed in the resin composition. It becomes difficult. On the other hand, if the fiber diameter exceeds 15 μm, the uneven distribution of the inorganic filler may cause a problem of variations in the mechanical properties of the substrate, and further impair the smoothness of the substrate. This decrease in smoothness causes a decrease in the reliability of wire bonding when the metal-coated resin molded product of the present invention is used as a circuit board or the like. Moreover, the effect which prevents that a weld line produces a crack falls that the aspect-ratio of the said fibrous inorganic filler is less than 5. On the other hand, when the aspect ratio exceeds 50, the inorganic filler is easily damaged during the kneading of the resin composition, and the moldability of the substrate may be lowered.

Further, in order to reduce the linear expansion coefficient of the substrate, whiskers may be mixed with the resin composition as an inorganic filler. A substrate obtained from a resin composition containing a whisker can have a superior dimensional stability and an improved surface strength. Improving the surface strength of the substrate can improve the adhesion between the substrate and the metal coating, and when the metal-coated resin molded product of the present invention is used as a circuit board, it effectively contributes to improving the reliability of bump bonding. To do. Examples of the whisker include silicon carbide, silicon nitride, zinc oxide, alumina, calcium titanate, potassium titanate, barium titanate, aluminum borate, calcium silicate, magnesium borate, calcium carbonate, magnesium oxysulfate, and the like. A whisker can be used. When titanate whiskers or borate whiskers are used, the effect of reducing the linear expansion coefficient of the substrate is extremely high. When titanate whiskers are used, the dielectric loss tangent of the substrate can be reduced in addition to improving the adhesion between the substrate and the metal film.

When the short fiber filler such as the above whisker is used as the inorganic filler, the fiber orientation can be suppressed when the substrate is formed, as compared with the case where the long fiber filler is used. Therefore, the obtained base has little anisotropy with respect to the linear expansion coefficient and shrinkage ratio. As a result, warpage and deformation of the substrate can be reduced, and a substrate having high dimensional accuracy can be obtained. Furthermore, the substrate has excellent flatness at the time of molding (initial flatness) and has an advantage that the flatness of the substrate can be reduced from fluctuating with temperature.

Further, from the viewpoint of obtaining better dimensional stability and high strength of the substrate, a plate-like inorganic filler such as talc, mica, glass flake, montmorillonite, smectite, etc. may be used. The plate-like inorganic filler preferably has an average length of 1 to 80 μm, more preferably 1 to 50 μm, and an average aspect ratio (length / thickness) of 2 to 60, more preferably 10 to 40. Further, from the viewpoint of suppressing the anisotropy of the substrate and improving the dimensional stability of the substrate without reducing the adhesion of the metal coating, the amount of the plate-like inorganic filler is the liquid crystalline polyester of component A and component B. The amount is preferably 10 to 40 parts by mass with respect to 100 parts by mass.

The fibrous inorganic filler, whisker, and plate-like inorganic filler may be used alone or in combination of two or more. A powdery or needle-like inorganic filler may be added to the resin composition. Further, carbon black or the like may be added as a colorant.

The metal-coated resin molded article of the present invention is obtained by molding a resin composition containing the liquid crystalline polyester of the above-described A component and B component, an epoxy group-containing ethylene copolymer, and, if necessary, an inorganic filler, etc. It is obtained by forming and then forming a metal film on the surface of the obtained substrate. The metal material constituting the metal film is not limited, but for example, a metal selected from the group consisting of copper, nickel, gold, aluminum, titanium, molybdenum, chromium, tungsten, tin, lead, and zinc, or selected from these groups An alloy composed of two or more kinds of metals can be used. Moreover, the metal material which comprises a metal film may be partially oxidized with the oxygen which exists in an environment.

Although the molding process of the substrate produced from the resin composition of the present invention is not limited, in order to enhance the effect of improving the adhesion by heat treatment of the metal-coated resin molded article described later, the resin composition is made of the first liquid crystalline polyester. It is preferable to knead at a temperature higher than the flow start temperature. As a typical substrate molding method, for example, a resin composition containing a first liquid crystalline polyester having a flow start temperature of 320 ° C. is kneaded at 340 ° C. by a twin-screw extruder to produce pellets. The substrate can be formed by injection molding the obtained pellets into a desired shape. Thus, the method of granulating once and obtaining a pellet has the tendency to improve adhesiveness compared with the case where it does not granulate irrespective of the presence or absence of the heat processing mentioned later. When the substrate is formed by injection molding, the melt viscosity of the resin composition is preferably 100 to 200 poise at a shear rate of 1000 / s.

After the substrate is produced as described above, it is preferable to heat-treat the substrate as a pretreatment when forming the metal film. The heat treatment is preferably a heat treatment at a temperature lower than the flow start temperature of the first liquid crystalline polyester contained in the resin composition. Specifically, the flow start temperature of the first liquid crystalline polyester is Tm1 (° C.). In this case, heat treatment in a temperature range of (Tm1-120) ° C. or higher and (Tm1-20) ° C. or lower is preferable. By performing such heat treatment, the adhesion between the surface of the substrate and the metal coating can be further increased, the coefficient of thermal expansion of the substrate can be further reduced, and the dielectric loss tangent of the substrate itself can be reduced. It is also effective against this. The metal-coated resin molded product obtained by performing this heat treatment is suitably used as a circuit board having excellent high frequency characteristics and the like. In the above heat treatment, if the heat treatment temperature is lower than (Tm1-120) ° C., the effect of improving the adhesion cannot be sufficiently obtained, and if the heat treatment temperature exceeds (Tm1-20) ° C., the substrate is warped. There is a risk of deformation. The time for the heat treatment is preferably between 1 and 4 hours. Moreover, when performing such heat processing, it is preferable to carry out in inert gas atmosphere, such as nitrogen gas, from a viewpoint of suppressing the oxidative degradation of a base | substrate. In the inert gas atmosphere, the residual oxygen concentration is preferably 1% by volume or less, and more preferably 0.5% by volume or less.

In addition, it is preferable to perform plasma treatment on the surface of the substrate prior to forming the metal film on the surface of the substrate. In the case of performing the above heat treatment, the plasma treatment may be performed before or after the heat treatment, but is more preferably performed after the heat treatment. Since the epoxy group-containing ethylene copolymer in the resin composition has a highly reactive functional group, the surface of the substrate is effectively activated by applying a plasma treatment, and adhesion to the metal film is achieved. The effect of the plasma treatment on the property improvement is extremely high.

The plasma processing can be performed using an existing plasma processing apparatus. For example, it is possible to use a plasma processing apparatus including a pair of electrodes opposed to each other in the chamber and a high frequency unit for applying a high frequency electric field between the electrodes. In this case, the substrate is placed on one electrode and the chamber is decompressed to about 10 ⁻⁴ Pa. Next, a plasma forming gas such as nitrogen gas or ammonia gas is introduced into the chamber so that the chamber internal pressure becomes 8 to 15 Pa. Next, using a high frequency unit, 300 W high frequency power (13.56 MHz) is applied between the electrodes for 10 to 100 seconds to generate plasma between the electrodes, and the cations and radicals in the generated plasma are transferred to the substrate surface. The substrate surface can be activated. Here, the activation of the substrate surface means that a nitrogen polar group or an oxygen polar group that easily binds to a metal is formed on the substrate surface by collision with a cation during plasma treatment. Thus, when a metal film is formed, the adhesion is further improved.

The plasma treatment conditions can be arbitrarily set as long as the surface of the resin substrate is not excessively roughened by the plasma treatment. Moreover, although the kind of plasma forming gas is not limited, it is preferable to use nitrogen. When nitrogen plasma is used, the elimination of carbon dioxide gas due to the cleavage of the ester bond of the liquid crystalline polyester constituting the substrate can be reduced compared to when oxygen plasma treatment is used. It is possible to avoid a decrease in strength of the surface, more specifically, the surface layer portion of the substrate.

Next, a method for forming a metal film on the surface of the substrate will be described.

For the formation of the metal coating, it is preferable to use a physical vapor deposition method such as sputtering, vacuum vapor deposition, or ion plating. As a pretreatment before forming the metal film, when the substrate is subjected to the plasma treatment as described above, the plasma treatment and the formation of the metal film are continuously performed without contacting the substrate with the atmosphere. It is preferable to carry out in a chamber.

When the DC sputtering method is employed as sputtering, for example, the chamber in which the substrate is disposed is decompressed to 10 ⁻⁴ Pa or less, and then an inert gas such as argon is introduced into the chamber so that the internal pressure becomes about 0.1 Pa. To introduce. Next, by applying a DC voltage of 500 V and bombarding the copper target, a copper film having a thickness of 200 to 500 nm is formed on the surface of the substrate as a metal film to obtain a metal-coated resin molded product. it can.

When the electron beam heating vacuum deposition method is employed as the vacuum deposition, for example, the chamber in which the substrate is disposed is decompressed to 10 ⁻⁴ Pa or less, and an electron current of 400 to 800 mA is collided with copper in the crucible. The copper is evaporated. As a result, a metal film can be obtained by forming a copper film having a thickness of about 300 nm on the surface of the substrate as a metal film.

In the case of employing ion plating, for example, the chamber in which the substrate is arranged is decompressed to 10 ⁻⁴ Pa or less, and copper is evaporated in the same manner as in the case of vacuum deposition. Further, an inert gas such as argon is introduced between the substrate and the crucible so that the internal pressure becomes 0.05 to 0.1 Pa. Next, with a desired bias voltage applied to the electrode holding the substrate, 500 W of high frequency power (13.56 MHz) is applied to the induction antenna to generate plasma in the chamber. As a result, a metal-coated resin molded product in which a copper film having a thickness of 200 to 500 nm is formed on the surface of the substrate can be obtained.

As described above, the substrate is molded using the resin composition containing components A to C, and if necessary, heat treatment and plasma treatment are performed as pretreatment, and the surface of the substrate is obtained by physical vapor deposition such as sputtering. A metal-coated resin molded product having a high degree of adhesion between the surface of the substrate and the metal film can be obtained by a series of methods for forming a metal film on the substrate. In particular, the metal-coated resin molded product obtained by the present invention has a high degree of adhesion without the need to use an adhesive or a chemical between the metal coating and the surface of the substrate. In addition, in the conventional metal-coated resin molded product described in Patent Document 1, when the mechanical strength and toughness of the surface layer portion of the substrate are deteriorated, the adhesion between the substrate surface and the metal film is reduced. However, in the present invention, a specific resin composition, that is, two kinds of liquid crystalline polyesters having different deflection temperatures under load and an epoxy group-containing ethylene copolymer effectively act, so that Since the tear resistance is greatly improved, the strength and toughness of the surface layer portion of the substrate can be prevented from being deteriorated as a result.

The metal-coated resin molded product of the present invention can be applied to various uses, but can be particularly suitably used as a circuit board. In this case, it is necessary to form a circuit pattern on the metal film of the metal-coated resin molded product. As a means for forming this circuit pattern, for example, laser patterning may be employed from the viewpoint that an unnecessary metal film other than the circuit pattern can be efficiently removed without reducing the adhesion of the metal film. Recommended. Since the metal-coated resin molded product of the present invention does not need to be roughened on the surface of the substrate in order to improve the adhesion to the metal film, the accuracy of circuit patterning associated therewith is reduced. In addition, it is possible to form a fine circuit pattern with high accuracy by laser patterning. Therefore, the metal-coated resin molded product of the present invention is also suitable for a three-dimensional circuit board (MID).

In addition, after applying laser patterning to the metal coating, a metal layer such as copper is added to the formed circuit pattern by electrolytic plating to form a circuit so that the total thickness becomes, for example, 5 to 20 μm. Alternatively, after the circuit pattern is formed, soft etching for reliably removing unnecessary metal film remaining on the substrate may be performed as necessary. Further, a nickel plating layer or a gold plating layer having a thickness of about several μm may be provided on the additional metal layer. Thus, the molded circuit board which has a desired circuit pattern can be obtained by using the metal-coated resin molded product of this invention.

Next, the present invention will be specifically described with reference to examples.

The deflection temperature under load was measured by the following method. That is, a test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 6.4 mm was formed using the polymer to be measured, and this test piece was measured by ASTM using a “heat distortion tester” manufactured by Yasuda Seiki Seisakusho. It measured by the load of 1.82 MPa (18.6 kg / cm < ² >) by the method based on D648.

(Component A: Synthesis of first liquid crystalline polyester)
911 g (6.6 mol) of p-hydroxybenzoic acid, 409 g (2.2 mol) of 4,4′-dihydroxybiphenyl, 274 g (1.65 mol) of terephthalic acid, and 91 g (0.55 mol) of isophthalic acid ) And acetic anhydride (1235 g, 12.1 mol) and 1-methylimidazole (0.17 g) are weighed and placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer and reflux condenser. Then, the inside of the reactor was sufficiently replaced with nitrogen gas. Subsequently, it heated up to 150 degreeC over 15 minutes under nitrogen gas stream, and also was made to recirculate | reflux at 150 degreeC for 1 hour.

Next, 1.7 g of 1-methylimidazole was further added, and the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. The content was taken out as deemed complete. The solid content obtained from the contents was cooled to room temperature, pulverized with a coarse pulverizer, and the resulting powder was heated from room temperature to 250 ° C. over 1 hour in a nitrogen atmosphere, and further from 250 ° C. to 285 ° C. The temperature was raised over 5 hours and held at 285 ° C. for 3 hours to proceed the polymerization reaction in a solid phase.

Thus, a first liquid crystalline polyester was obtained. The flow start temperature of this first liquid crystalline polyester was measured using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), and was 327 ° C.

Further, a part of the first liquid crystalline polymer was pelletized by granulation, and processed into a test piece for measuring a deflection temperature under load by injection molding. It was 241 degreeC when the deflection temperature under load was measured using the obtained test piece.

(Component B: Synthesis of second liquid crystalline polyester)
879 g (6.0 mol) of p-hydroxybenzoic acid, 559 g (3.0 mol) of 4,4′-dihydroxybiphenyl, 498 g (3.0 mol) of isophthalic acid, and 1348 g (13.2 mol) of acetic anhydride Further, 0.19 g of 1-methylimidazole was weighed, and these were put into a reactor equipped with a stirrer, a torque meter, a nitrogen gas introduction tube, a thermometer and a reflux condenser, and the reactor was sufficiently filled with nitrogen gas. Replaced with. Subsequently, it heated up to 150 degreeC over 15 minutes under nitrogen gas stream, and also was made to recirculate | reflux at 150 degreeC for 1 hour.

Next, the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride, and the time when an increase in torque was recognized was regarded as the completion of the reaction, and the contents were taken out. The solid content obtained from the contents was cooled to room temperature and pulverized with a coarse pulverizer, and then the obtained powder was heated from room temperature to 200 ° C. over 1 hour in a nitrogen atmosphere, and further from 200 ° C. to 298 ° C. The temperature was raised over 5 hours and held at 298 ° C. for 3 hours to allow the polymerization reaction to proceed in the solid phase.

Thus, a second liquid crystalline polyester was obtained. The flow initiation temperature of this second liquid crystalline polyester was measured in the same manner as described above, and it was 318 ° C. Further, the deflection temperature under load of this second liquid crystalline polyester was measured in the same manner as described above, and it was 133 ° C.

On the other hand, the product number “BF-E” of “Bond First” (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. was used as the ethylene copolymer of component C epoxy group. This “bond first BF-E” is an ethylene-glycidyl methacrylate copolymer (glycidyl methacrylate content 12 mass%, MFR = 3 g / 10 min). The MFR (melt flow rate) is a value measured in accordance with JIS-K7210 under conditions of 190 ° C. and 2160 g load.

Furthermore, milled glass fiber (MGF: “EFH75-01” (fiber diameter: 10 μm, aspect ratio: 10) manufactured by Central Glass Co., Ltd.) was used as an inorganic filler.

(Examples 1 to 4, Comparative Examples 1 and 2)
The first liquid crystalline polyester, the second liquid crystalline polyester, “bond first BF-E”, and milled glass fiber (MGF) “EFH75-01” are mixed in the blending amounts shown in Table 1 to obtain a resin composition. A product was prepared. In Examples 1 to 4, resin compositions were prepared by changing the ratio of the first liquid crystalline polyester and the second liquid crystalline polyester.

Next, pellets of this resin composition were prepared at 340 ° C. using a twin screw extruder (“PCM-30” manufactured by Ikekai Tekko Co., Ltd.). The obtained pellets were injection molded under the conditions of a cylinder temperature of 350 ° C. and a mold temperature of 130 ° C. using an injection molding machine “PS40E5ASE” manufactured by Nissei Plastic Industry Co., Ltd. Got.

Next, the substrate thus obtained was heat-treated under a nitrogen atmosphere at 280 ° C. for 3 hours, and the substrate was not subjected to the heat treatment. Thus, a metal film was formed.

First, the surface of the substrate was plasma-treated, and then a metal film was formed using a DC magnetron sputtering apparatus. That is, the substrate was placed in the chamber of the plasma processing apparatus, and the chamber was depressurized to about 10 ⁻⁴ Pa. Next, nitrogen gas was introduced into the chamber so that the gas pressure in the chamber became 10 Pa, and 300 W of high frequency (13.56 MHz) power was applied between the electrodes for 30 seconds to perform plasma treatment on the substrate.

After the plasma treatment, the pressure in the chamber was reduced to 10 ⁻⁴ Pa or less. In this state, argon gas was introduced into the chamber to a gas pressure of 0.1 Pa, a copper target was bombarded by applying a DC voltage of 500 V, and a 400 nm film thickness was formed on the plasma-treated surface of the substrate. A metal coating consisting of a copper coating was formed.

Thereafter, a pattern with a width of 5 mm is formed on the metal film by laser irradiation, and a copper pattern is plated on the metal film pattern by electrolytic plating to form a circuit pattern for a peel strength test having a thickness of 15 μm on the surface of the substrate. A circuit forming substrate was obtained.

For the circuit-formed substrates obtained in Examples 1 to 4 and Comparative Examples 1 and 2 as described above, the peel strength of the circuit pattern and the thermal deformation temperature (DTUL: deflection temperature under load) of the substrate were measured. The peel strength was measured using a universal testing machine (“EG Test” manufactured by Shimadzu Corporation) with respect to a 90-degree peel strength in a direction perpendicular to the resin flow during molding. The results are shown in Table 1. FIG. 1A shows the relationship between the ratio of the second liquid crystalline polyester to the total amount of the first liquid crystalline polyester and the second liquid crystalline polyester and the peel strength, and the relationship with the thermal deformation temperature (DTUL). Is shown in FIG.

As seen in Table 1 and FIG. 1 (a), as the liquid crystalline polyester, the first liquid crystalline polyester having a deflection temperature under load of 200 ° C. or higher is subjected to a load deflection lower than the load deflection temperature of the first liquid crystalline polyester. It is confirmed that by using a second liquid crystalline polyester having a temperature in combination, the peel strength is improved and a metal film can be formed with higher adhesion. In this case, if the content of the second liquid crystalline polyester increases, the heat distortion temperature decreases and the heat resistance decreases as seen in FIG. 1B, so the content of the second liquid crystalline polyester is It is preferable that it is 50 mass% or less. In particular, when the content of the second liquid crystalline polyester exceeds 30% by mass, the thermal deformation temperature is greatly reduced as shown in FIG. 1B, and as shown in FIG. Even if the content of the liquid crystalline polyester exceeds 30% by mass, the effect of improving the peel strength is not so much observed. For this reason, it is more preferable that the content rate of 2nd liquid crystalline polyester is 30 mass% or less.

Also, as shown in Table 1 and FIG. 1 (a), it is confirmed that the peel strength is increased by heat-treating the substrate, and the effect of improving the adhesion can be obtained.

Also, in Example 2 and Comparative Example 1 (with heat treatment), the shrinkage rate of the substrate was measured. The shrinkage rate is the shrinkage rate of the substrate size with respect to the mold size. A flat plate is prepared under the molding conditions described above, and the substrate size in the MD (resin flow direction) and TD (perpendicular to the resin flow direction). And the shrinkage ratio with the mold dimensions was calculated. The results are shown in Table 2.

As seen in Table 2, by using the second liquid crystalline polyester in combination with the first liquid crystalline polyester as in Example 2, MD (resin flow direction) and TD (perpendicular to the resin flow direction) ) Is reduced, the molding warpage can be reduced, the dimensions of the substrate can be increased, and thermal deformation due to reflow or the like can be suppressed.

(Examples 5 to 8, Comparative Examples 3 and 4)
The first liquid crystalline polyester, the second liquid crystalline polyester, “bond first BF-E”, and milled glass fiber (MGF) “EFH75-01” are mixed in the blending amounts shown in Table 3 to obtain a resin composition. A product was prepared. In Examples 5 to 8, resin compositions were prepared by changing the ratio of the first liquid crystalline polyester and the second liquid crystalline polyester and further changing the amount of “bond first BF-E”. Example 6 has the same composition as Example 2 and Comparative Example 3 has the same composition as Comparative Example 1.

Using this resin composition, a substrate was molded, subjected to heat treatment, subjected to plasma treatment in the same manner as described above, and then a copper film was formed, followed by laser patterning to obtain a circuit forming substrate. .

For this circuit-formed substrate, the peel strength of the circuit pattern was measured, and the results are shown in Table 3.

As can be seen in Table 3, the peel strength of each of the examples in which the second liquid crystalline polyester was used in combination with the first liquid crystalline polyester was higher than that of Comparative Example 3 in which the first liquid crystalline polyester was used alone. In addition, increasing the amount of “Bond First BF-E” showed a tendency to improve the peel strength.

Claims (13)

1. A: First liquid crystalline polyester having a deflection temperature under 200 ° C. or higher B: Second liquid crystalline polyester having a deflection temperature lower than the deflection temperature under load of the first liquid crystalline polyester C: Ethylene copolymer containing an epoxy group Compound (however, the epoxy group-containing ethylene copolymer contains 50 to 99.9% by mass of ethylene units in the molecule, 0.1 to 30% by mass of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units) % Included)
   A substrate obtained by molding a resin composition containing the above components A, B and C and having component C in the range of 0.1 to 25 parts by mass with respect to a total of 100 parts by mass of component A and component B And a metal coating formed on the surface of the substrate.
2. 2. The metal-coated resin molded product according to claim 1, wherein in the resin composition, the component B is 1 to 50% by mass with respect to the total amount of the component A and the component B.
3. The metal-coated resin molded product according to claim 2, wherein component B is 30% by mass or less based on the total amount of component A and component B.
4. In the second liquid crystalline polyester, divalent aromatic groups are linked by an ester bond, and the divalent aromatic groups are 1,2-phenylene group, 1,3-phenylene group, 2 And at least one aromatic group selected from 3-naphthalene groups, and the total amount of these aromatic groups is 10 to 45 mol% based on the total amount of divalent aromatic groups The metal-coated resin molded product according to any one of claims 1 to 3.
5. The epoxy group-containing ethylene copolymer contains 80 to 98% by mass of ethylene units and 2 to 15% by mass of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units in the molecule. The metal-coated resin molded product according to any one of claims 1 to 4.
6. D: A fibrous inorganic filler having a diameter of 6 to 15 μm and an aspect ratio of 5 to 50. The resin composition contains the component D in addition to the components A to C. The metal-coated resin molded product according to any one of the above items.
7. The metal coating is made of a metal selected from copper, nickel, gold, aluminum, titanium, molybdenum, chromium, tungsten, tin, lead, and zinc, or an alloy of two or more metals selected from these metals. The metal-coated resin molded product according to any one of claims 1 to 6, wherein:
8. The metal-coated resin molded product according to any one of claims 1 to 7, wherein a circuit pattern is formed by the metal coating.
9. A metal-coated resin molding comprising: a molding step of molding the resin composition according to any one of claims 1 to 8 to obtain a substrate; and a coating step of forming a metal film on the surface of the substrate. Product manufacturing method.
10. 10. The method for producing a metal-coated resin molded product according to claim 9, further comprising a step of performing a plasma treatment on the surface of the substrate before the coating step.
11. Prior to the coating step, the substrate is heat-treated at a temperature of (Tm1-120) ° C. to (Tm1-20) ° C. [where Tm1 represents the flow start temperature (° C.) of the first liquid crystalline polyester]. The method for producing a metal-coated resin molded article according to claim 9 or 10, comprising a step.
12. The method for producing a metal-coated resin molded article according to any one of claims 9 to 11, wherein the coating step is a step of forming a metal film on the surface of the substrate by physical vapor deposition.
13. The method for producing a metal-coated resin molded product according to any one of claims 9 to 12, further comprising a step of forming a circuit pattern by performing laser patterning on the metal coating.

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