JPH071670A - Thermotropic liquid crystal resin bonding structure and bonding method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] A simple method that uses a highly safe and easy-to-handle liquid as a treatment liquid and performs it under relatively mild conditions, and coats other materials without impairing the smoothness of the product surface. Provided are a thermotropic liquid crystal resin bonding structure capable of forming a resin and a bonding method thereof. [Structure] (1) A bonding structure in which one surface forming the bonding is a surface of a molded product made of ultrasonically treated thermotropic liquid crystal resin. (2) A method of joining a thermotropic liquid crystal resin, which comprises applying ultrasonic vibration to the thermotropic liquid crystal resin and then joining the same.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a surface of a molded article made of a thermotropic liquid crystal resin (hereinafter, sometimes referred to as LCP) useful in the fields of electric / electronic parts, automobile parts, mechanical parts, etc. , Coating with metallization by sputtering, or laminating other synthetic resin coatings, or coating with paints, adhesives, etc. The present invention relates to a joined structure formed by joining and a joining method thereof.

[0002]

2. Description of the Related Art In recent years, LCP has attracted attention as a new synthetic resin and its application has been expanding. In order to functionalize or decorate the molded product, a metal film is formed on the surface by plating, vapor deposition, sputtering or the like. It has become necessary to laminate other synthetic resins, apply paint, and join various materials with an adhesive.

Since LCP is generally chemically stable, when forming a film of another material on the surface of a molded article made of LCP, chemical bonding force between the LCP and the film cannot be expected so much. Therefore, it is often necessary to pretreat the surface of the LCP molded product by some method. LC for this
It is possible to roughen the P surface (generally referred to as etching). Various methods have been proposed for this surface roughening. For example, JP-A-62-54073
The publication discloses the use of a chromic acid mixture as an etching solution for pretreatment of metallizing. But,
The potassium dichromate used here has a problem of environmental pollution, and the treatment of the waste liquid requires a great deal of cost. Also, this is 95% sulfuric acid, 2% potassium dichromate, 3% water.
There is a problem in handling because the concentration is extremely high (weight ratio).

Further, in Japanese Patent Laid-Open No. 1-98637, L
A method in which CP is mixed with a specific filler and etching is performed with a sulfuric acid solution is disclosed. In this case, the sulfuric acid concentration is 80%.
% Or more is required and there is a problem in handling.

When the material to be joined of the LCP molded article is a film formed on the surface and it is a metal, for example, a practical method in the case of plating, see "Journal of the Adhesion Society of Japan, Vol. 26,". No. 2, p. 21 (1990) ”. Here, it is pointed out that the surface condition after etching is "rougher than other resins (that is, resins other than LCP) and the appearance after plating is poor".

As described above, one of the problems in the method of joining LCP molded products is that the pretreatment liquid has problems of environmental pollution and safety, and it is necessary to use a pretreatment liquid that is high in concentration and difficult to handle. That is. Another problem is that this pretreatment is etching (meaning roughening the surface), which is intended to improve the bond strength by the mechanical anchoring effect in the bond formation, Such surface roughening treatment may inevitably impair the smoothness of the product surface.

[0007]

SUMMARY OF THE INVENTION The present invention solves these problems of the prior art and uses a simple method, which uses a highly safe and easy-to-handle liquid as a treatment liquid, and performs the treatment under relatively mild conditions. It is an object of the present invention to provide a thermotropic liquid crystal resin joining structure capable of forming a coating film of another material without impairing the smoothness of the surface and a joining method thereof.

This is further summarized below. Industrially useful molded products made of LCP, which is a material with excellent mechanical strength, heat resistance, dimensional accuracy, electrical properties, flame retardancy, molding processability, etc., can be metalized by plating, vapor deposition, sputtering, etc. on the surface. By adding means such as forming a film, laminating another synthetic resin, applying a paint, or joining with an adhesive, it is decorated or functionalized to increase the added value.

A method for forming a coating film is provided in which the adhesion between the LCP and the coating film of another material is sufficient in practical use.

[0010] An industrially advantageous pretreatment method for forming a film, which can be performed under relatively mild conditions using a highly safe liquid, is provided.

The product formed with the coating of another material has an excellent appearance, and gives an LCP molded product having high commercial value.

[0012]

[Means for Solving the Problems] The inventors of the present invention have made various investigations to solve these problems and arrived at the present invention.

That is, the present invention relates to a joint structure characterized in that one surface constituting the joint is a surface of a molded product made of ultrasonically treated thermotropic liquid crystal resin.

The present invention also relates to a method of joining the thermotropic liquid crystal resin, which comprises applying ultrasonic vibration to the thermotropic liquid crystal resin and then joining the same.

The present invention will be further described below. The thermotropic liquid crystal polymer referred to in the present invention is a thermoplastic meltable polymer that exhibits optical anisotropy when melted. As described above, the polymer exhibiting optical anisotropy when melted has a property that the polymer molecular chains have a regular parallel arrangement in the melted state. The properties of the optically anisotropic molten phase can be confirmed by a usual polarization inspection method using a crossed polarizer.

Examples of the above-mentioned liquid crystal polymer include liquid crystal polyester, liquid crystal polycarbonate, liquid crystal polyester imide and the like, specifically, (all) aromatic polyester, polyester amide, polyamide imide, polyester carbonate, polyazomethine and the like. Can be mentioned.

The thermotropic liquid crystal polymer is generally composed of an elongated and flat molecular structure, has high rigidity along the long chain of the molecule, and has a plurality of chain extension bonds in a coaxial or parallel relationship. .

In the thermotropic liquid crystal polymer used in the present invention, a part of one polymer chain is composed of polymer segments forming an anisotropic melt phase, and the remaining part does not form an anisotropic melt phase. Also included are polymers composed of polymer segments. Further, it also includes a composite of a plurality of thermotropic liquid crystal polymers.

Typical examples of the monomer constituting the thermotropic liquid crystal polymer include (A) at least one aromatic dicarboxylic acid, (B) at least one aromatic hydroxycarboxylic acid compound, and (C) aromatic diol. At least one type of compound, (D) (D ₁ ) aromatic dithiol, (D ₂ ) aromatic thiophenol, (D ₃ ) at least one type of aromatic thiolcarboxylic acid compound, (E) aromatic hydroxy At least one kind of amines and aromatic diamine compounds can be used.

Although these may be configured independently,
Most of them are (A) and (C), (A) and (D), (A),
(B) and (C), (A), (B) and (E), or (A), (B), (C) and (E), and so on.

The above-mentioned (A) aromatic dicarboxylic acid type compounds include terephthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-triphenyldicarboxylic acid, 2,6-
Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,
4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,
3'-dicarboxylic acid, diphenoxyethane-3,3'-
Aromatic dicarboxylic acids such as dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid,
Examples thereof include alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid and ethoxy terephthalic acid.

(B) Aromatic hydroxycarboxylic acid compounds include aromatic hydroxy such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid. Carboxylic acid or 3-methyl-4-hydroxybenzoic acid, 3,5
-Dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl -2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid,
2-chloro-4-hydroxybenzoic acid, 3-chloro-4
-Hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3
-Bromo-4-hydroxybenzoic acid, 6-hydroxy-5
-Alkyl, alkoxy or halogen substitution products of aromatic hydroxycarboxylic acids such as -chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid and 6-hydroxy-5,7-dichloro-2-naphthoic acid Is mentioned.

As the aromatic diol (C), 4,4 '
-Dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, hydroquinone, resorcin, 2,6-naphthalenediol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3 , 3'-Dihydroxydiphenyl ether, 1,6-naphthalenediole, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane and other aromatic diols or chlorohydroquinone Alkyl, alkoxy or halogen substitution products of aromatic diols such as methyl hydroquinone, t-butyl hydroquinone, phenyl hydroquinone, methoxy hydroquinone, phenoxy hydroquinone, 4-chlororesorcinol and 4-methylresorcinol. That.

Examples of the aromatic dithiol (D ₁ ) include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol and 2,7-naphthalene-dithio. -Ru and the like.

As the (D ₂ ) aromatic thiophenol,
4-mercaptophenol, 3-mercaptophenol
And 6-mercaptophenol and the like.

Examples of (D ₃ ) aromatic thiol carboxylic acids include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

Examples of (E) aromatic hydroxyamine and aromatic diamine compounds include 4-aminophenol and N-
Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine,
N, N'-dimethyl-1,4-phenylenediamine, 3
-Aminophenol, 3-methyl-4-aminophen-
2-chloro-4-aminophenol, 4-amino-
1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenylether, 4-amino-4'-hydroxydiphenylmethane,
4-amino-4'-hydroxydiphenyl sulfide,
4,4'-diaminophenyl sulfide (thiodianiline), 4,4 'diaminodiphenyl sulfone, 2,5-
Diaminotoluene, 4,4'-ethylenedianiline,
4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,
4'-diaminodiphenyl ether (oxydianiline) and the like can be mentioned.

The thermotropic liquid crystal polymer used in the present invention can be produced from the above-mentioned monomers by various ester forming methods such as melt acidolysis method and slurry polymerization method.

The thermotropic liquid crystalline polyesters suitable for use in the present invention as a molecular weight have a molecular weight of from about 2000 to about 2000.
200,000, preferably about 4000 to 100,000. The molecular weight can be measured, for example, by measuring the end groups of a compressed film by infrared spectroscopy. GPC, which is a general measurement method that involves solution formation
You can also do

Among the thermotropic liquid crystal polymers obtained from these monomers, aromatic polyesters which are (co) polymers containing the monomer unit represented by the following general formula (1) as an essential component are preferable. Particularly preferred is an aromatic polyester containing 5 mol% or more of the monomer unit.

[0031]

[Chemical 1]

A particularly preferred aromatic polyester of the present invention is a polyester represented by the following formula (2) having repeating units each having a structure derived from three compounds of p-hydroxybenzoic acid, phthalic acid and biphenol. The repeating unit having a structure derived from biphenol of the polyester represented by the following formula (2) may be a polyester in which a part or all of the repeating unit is substituted with a repeating unit derived from dihydroxybenzene. A polyester represented by the following formula (3) having repeating units each having a structure derived from two compounds of p-hydroxybenzoic acid and hydroxynaphthalenecarboxylic acid.

[0033]

[Chemical 2]

[0034]

[Chemical 3]

The thermotropic liquid crystal resin of the present invention comprises 1
It can also be used as a seed or a mixture of two or more.

The thermotropic liquid crystal resin may be used alone to form the molded article of the present invention. However,
An inorganic filler is often added for the purpose of improving the strength and heat resistance of the thermotropic liquid crystal resin, or improving the anisotropy, processability, dimensional accuracy and the like. In the present invention, such a mode is a preferred mode because the strength of the joint is improved by using a resin containing an inorganic filler.

This inorganic filler is not particularly limited, and its shape may be, for example, a fibrous, granular or flake-shaped filler. Examples of the fibrous filler include glass fiber, carbon fiber, alumina fiber, gypsum fiber, shirasu fiber, asbestos fiber, metal fiber and various whiskers.

The particularly preferred inorganic filler in the present invention is a filler having a powder / granular shape. By using this, not only a molded article having a smooth surface can be obtained, but also adhesion with a coating film of another material. Power improves. If the aspect ratio is 10 or less, the shape does not have to be spherical,
It may have an irregular shape or a flat shape.

As the powder / granular filler, talc, mica,
Wollastonite, kaolin, sericite, clay, bentonite, silicates such as alumina silicate, alumina,
Metal oxides such as magnesia, zirconia, titanium oxide, zinc oxide, iron oxide, antimony oxide, calcium carbonate,
Examples thereof include carbonates such as magnesium carbonate and dolomite, sulfates such as calcium sulfate and magnesium sulfate, calcium phosphate, calcium pyrophosphate, glass beads, glass flakes, molybdenum disulfide, silicon nitride, boron nitride and silicon carbide. These may be hollow, such as glass balloons, shirasu balloons, carbon balloons, hollow glass fibers and the like.

The above-mentioned fillers may be used as a mixture of two or more kinds, and if necessary, they may be pretreated with a coupling agent such as a silane type or titanate type before use.

These fillers are preferably added in an amount of 5 to 80% by weight, more preferably 10 to 70% by weight. If it is less than 5% by weight, the above-mentioned effect of improving the strength and workability may not be exhibited, and the adhesion of the coating film may be insufficient. When it exceeds 80% by weight, mechanical strength and the like are rather deteriorated, which is not preferable.

The so-called L containing another polymer is mixed.
It is also possible to use it as a CP polymer blend or an LCP polymer alloy. Examples of other resins that can be blended include polyolefin resins or elastomers such as polyethylene, polypropylene, polybutene and polymethylpentene, polyester resins or elastomers such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, and aliphatic resins. Examples thereof include various engineering plastics such as polyamide resins or elastomers such as nylon and aromatic nylon, polystyrene resins or elastomers, polycarbonate resins, fluorine resins, polysulfone resins, polyoxymethylene resins, polyphenylene sulfide resins and polyketone resins.

In addition, antioxidants and heat stabilizers (for example, hindered phenols, hydroquinones, phosphites, thioethers) and light stabilizers (thermotropic liquid crystal resins) within the range that does not impair the object of the present invention. For example, benzophenones, benzotriazoles, hindered amines, salicylates, resorcinols), lubricants and mold release agents, coloring agents including dyes and pigments (eg carbon black, titanium white, phthalocyanine, cadmium sulfide), flame retardants, plasticizers. Ordinary additives such as antistatic agents can be added to impart predetermined characteristics.

In the present invention, this thermotropic liquid crystal resin is used as a molded product molded by various conventionally known molding means. Examples of the shape thereof include film-shaped, plate-shaped, disk-shaped, rectangular, columnar, rod-shaped molded products and more complicated molded products depending on the molding method and the like, but are not particularly limited thereto. The most commonly applied moldings are those molded by injection molding. Other examples include molded products formed by extrusion molding such as pipes, films and sheets, and molded products formed by blow molding such as bottles and irregularly shaped products, but are not limited to these.

In the present invention, before forming a coating film of metal or the like or a resin laminate on the above-mentioned molded article, that is, before forming a joint structure, in a medium for transmitting an appropriate ultrasonic wave such as gas or liquid, it is preferable. It is an essential requirement to perform pretreatment by applying ultrasonic vibration to the surface of the molded body in a liquid and to use the molded article thus treated.

The device for applying ultrasonic vibration is not particularly limited as long as it has a structure capable of applying ultrasonic waves through a liquid. In such a device, a piezoelectric oscillator using crystal or the like, an electrostrictive oscillator using barium titanate or the like, or a magnetostrictive oscillator using nickel, ferrite or the like, which is obtained by a transmitter such as 20 KHz or more, is generally used. There is an ultrasonic wave having a frequency of about 50 KHz that vibrates the container, and the sound wave propagates from the container to the liquid, and the ultrasonic wave is applied to the molded product through the liquid. There are various ultrasonic cleaning devices such as an experimental one with an output of several tens to several hundreds of watts depending on the shape and size of an object to be applied, and an industrial one with several kilowatts to several tens of kilowatts. is there.

In order to apply ultrasonic vibration to the molded product, for example, the following liquid is put in the container of the ultrasonic cleaning device, and the thermotropic liquid crystal resin molded product degreased as necessary is immersed in the liquid. Is applied.

In this case, the temperature at the time of application may be room temperature, but the treatment effect may be improved by heating to a temperature of 40 ° C. or higher and not exceeding the boiling point of the liquid. The frequency of the applied ultrasonic wave is 20 KHz or more, preferably 2
It is 5 KHz or more. The upper limit value of the frequency is not particularly limited, but ultrasonic waves having an excessively high frequency are expensive in terms of the apparatus, and therefore the frequency is usually 10 MHz or less.

The intensity of the ultrasonic waves is not particularly limited, but it is usually 0.1 W / cm ² or more in the liquid. The upper limit is also not particularly limited, but a phenomenon such as a rise in liquid temperature is observed at an excessively high output, and therefore the output is usually 100 W / cm ² or less.

In the present invention, the ultrasonic wave application time is preferably 2 minutes or more, and more preferably 5 minutes or more, in order to sufficiently exert the adhesion force with the coating film. Before providing the assembly process after molding electronic parts made of synthetic resin,
Ultrasonic waves may be applied in an organic solvent such as chlorofluorocarbon, but since this is for the purpose of degreasing, it is usually performed within 1 minute at room temperature. Under such conditions, the effect of the pretreatment of the present invention is not achieved. Does not develop.

The liquid used in the ultrasonic treatment in the present invention is not particularly limited, and an alkaline aqueous solution, an acidic aqueous solution,
Examples include organic solvents and water. As the alkaline aqueous solution, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, aluminum hydroxide,
An aqueous solution of an alkaline substance such as barium hydroxide or ammonia can be used, and two or more types of alkaline substances can be mixed and used. Acidic aqueous solutions include sulfuric acid, nitric acid,
An aqueous solution of an acidic substance such as hydrochloric acid, chromic acid or dichromic acid may be used, and the acidic substance may be used as a mixture of two or more kinds. As the organic solvent, aliphatic hydrocarbons such as toluene, xylene, and tetralin, hexane, aliphatic hydrocarbons such as heptane, alicyclic hydrocarbons such as decalin, tetrafluoroethylene, trifluoroethylene, tetrachloroethane, trichloroethane , Halogenated hydrocarbons such as trichlorethylene and carbon tetrachloride, esters such as ethyl acetate and butyl acetate, ketones such as acetone and methyl ethyl ketone,
Examples include alcohols such as ethyl alcohol and isopropyl alcohol, organic acids such as acetic acid and propionic acid, aprotic solvents such as n-methylpyrrolidone, fluorophenolic compounds such as pentafluorophenol, dimethylformamide and dimethylsulfoxide. . These can also be used as a mixture of two or more kinds. Further, the organic solvent can be mixed with an alkaline aqueous solution or an acidic aqueous solution.

Of these, in the present invention, it is particularly preferable to use an alkaline aqueous solution for ultrasonic treatment.

The concentration of the alkaline or acidic aqueous solution may be lower than that used in ordinary etching. The amount of the alkaline or acidic substance dissolved in water is preferably 100 g / l or more, more preferably 200 g / l or more. This is 1
If it is less than 00 g / l, the adhesion strength of the coating may not be sufficient. The upper limit of the concentration is not limited, but in general, the higher the concentration, the smoothness of the coating may be impaired. Therefore, the concentration is preferably 1000 g / l or less, more preferably 650 g.
It is better to treat with / l. This concentration is related to the ultrasonic treatment time to be described later, and when the time is short, a relatively high concentration is preferable, and when the time is long, a relatively low concentration is preferable.

The effect may be further increased by immersing the ultrasonic treatment in a liquid different from the treatment liquid prior to the ultrasonic treatment. For example, when an acidic aqueous solution is used as the ultrasonic treatment liquid and the immersion liquid is immersed in an alkaline aqueous solution, or vice versa, the effect may be improved. When water is used as the ultrasonic treatment liquid, good results can be obtained by preliminarily immersing it in an acidic or alkaline aqueous solution.

The coating formed on the surface of the thermotropic liquid crystal resin molded article is a coating made of any material such as metal, synthetic resin, paint and adhesive.

Although there are various methods for forming the metal coating, chemical plating, electroplating, sputtering, vapor deposition and the like are common.

For the plating step, a conventionally known plastic plating method can be adopted. Generally, a molded product is first degreased with an organic solvent, a surfactant or the like. Usually, this is followed by etching treatment with a concentrated solution of sodium hydroxide or sulfuric acid, but in the method of the present invention, the above-mentioned ultrasonic pretreatment is performed. Of course, the ultrasonic treatment of the present invention and the conventional etching treatment can be used together, if necessary.

Next, chemical (electroless) plating is performed through each step of conditioning, catalyst application and activation. After that, electroplating is performed if necessary. Copper, nickel and the like are generally used as the metal used for the chemical plating. There are various metals used for electroplating, examples of which include copper, nickel, chromium, gold, silver, tin-lead alloys, and the like. The thickness of the plated metal layer formed by the plastic plating method is generally in the range of 200Å to 1000 μm.

The sputtering method is, for example, 1 × 10 ⁻³ to
In a high vacuum of 2 × 10 ⁻⁴ Torr, a high voltage of, for example, 10,000 V or more is applied between the positive and negative electrodes to generate glow discharge, thereby scattering the cathode metal, and the scattered metal is the thermotropic liquid crystal. It deposits on the surface of a resin molded product to form a metal coating. Coexistence of an inert gas such as argon is also performed. There are various target metals, other than copper, gold, chromium, aluminum, etc.
A film of a metal oxide such as tin oxide or indium oxide can also be formed.

The vapor deposition method includes a vacuum vapor deposition method and a chemical vapor deposition method. The vacuum deposition method is, for example, 1 × 10 ⁻³ to 1 × 10 ⁻⁴ Tor.
A metal film is formed on the surface of a molded body by heating a vapor deposition material under a high vacuum of about r and depositing a metal again on the surface of a molded article which is the surface of a substrate. used.

In the chemical vapor deposition method, a metal or a metal oxide is vaporized and sent to a reaction chamber, and a metal or a metal oxide is deposited on the surface of a molded product in a state close to a thermodynamic equilibrium state to form a film of these. Is the way to do it. Examples of the substance that precipitates include metals such as boron, oxides such as silica and alumina, carbides such as silicon carbide, and nitrides such as silicon nitride.

In addition, it is also possible to use an ion plating method or the like in which the evaporated particles of the base material from the evaporation source are ionized in plasma under high vacuum and the ions are attached to perform coating. As a method of generating plasma, there are a direct current excitation method of applying a direct current electric field and a high frequency excitation method of applying a high frequency electric field. Either method can be adopted.

The thickness of the coating film formed by the sputtering method, the vapor deposition method, the ion plating method or the like is generally about 200Å to 1000Å.

After the ultrasonic treatment, if the thermotropic liquid crystal resin molded article is coated with a conventionally known paint for plastics, the adhesive strength of the paint is improved. The paint for coating the thermotropic liquid crystal resin molded product is not particularly limited,
Any paint that is commercially available for plastics can be used. For example, various paints such as epoxy-based, acrylic-based, melamine-based, alkyd-based and urethane-based solvent-based paints can be mentioned. The coating method of these paints can also be a conventionally known coating method, for example, a general method such as spray coating, brush coating, etc. after degreasing and cleaning the ultrasonically treated thermotropic liquid crystal resin molded article appropriately. Is applied. Generally, the paint film thickness is the dry film thickness,
It is in the range of 0.1 to 100 μm.

If the ultrasonically treated surfaces are bonded together with an adhesive, the bonding strength is improved. This adhesive is not particularly limited, and any of the adhesives that are usually commercially available for bonding plastics can be used. For example, acrylic,
Examples include various adhesives such as cyanoacrylate-based, melamine-based, urethane-based or phenol-based solvent-type or reactive-type adhesives. The thermotropic liquid crystal resin molded article that has been pretreated is applied and adhered by a generally known method such as spraying, a roll coater, and dipping. As the mating material to be bonded, an arbitrary material such as synthetic resin or metal is appropriately selected. The thickness of the adhesive is generally 0.5 to 1000 μm.

It is also possible to bond the thermotropic liquid crystal resin molded product to the thermotropic liquid crystal resin molded product, which is previously subjected to ultrasonic treatment, by pressure-bonding the molten thermoplastic resin to the film or sheet, followed by cooling. . The thermoplastic resin is not particularly limited, and examples thereof include polyester resins or elastomers such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, aliphatic nylon,
The synthetic resins exemplified for blending or alloying with a thermotropic liquid crystal resin such as a polyamide resin such as aromatic nylon or an elastomer can be used. As a method for melt-bonding, a method of extruding a melted thermoplastic resin from a T-die onto a thermotropic liquid crystal resin molded product that has been ultrasonically processed in advance, for example, a film or a sheet, and performing a pressure-bonding by a heat press, etc. Can be adopted. By doing so, a laminate in which thermoplastic resins are laminated can be obtained. By performing ultrasonic treatment in advance as in the present invention, the adhesive strength is improved.

The thickness of the thermoplastic resin to be melt-pressed is not particularly limited, but is usually in the range of 0.1 μm to 5 mm.

[0068]

The present invention will be described in more detail with reference to the following examples.

[Thermotropic liquid crystal resin used] L
CP-1: A thermotropic liquid crystal polyester resin having repeating constitutional units respectively derived from p-hydroxybenzoic acid / terephthalic acid / biphenol / isophthalic acid was prepared (optical anisotropy using a polarization microscope equipped with a hot stage). Was observed to show optical anisotropy in the molten state at 340 ° C. or higher).

To this, 50% by weight of granular calcium carbonate (average particle diameter 5 μm) was blended and kneaded and granulated using a twin-screw extruder.

LCP-2: 40% by weight of clay (average particle size 3 μm) was blended with the above thermotropic liquid crystal polyester resin, and the mixture was kneaded and granulated using a twin-screw extruder.

[Production of Molded Article] Using the above kneaded and granulated resin, a square plate having a thickness of 1.6 mm and a side of 100 mm was molded using an injection molding machine (IS-80 manufactured by Toshiba Machine).

[Ultrasonic treatment] As the ultrasonic treatment apparatus, VS-150 manufactured by Inouchi Seieido Co., Ltd. was used. Processing conditions, processing solutions, etc. are described in Examples below.

[Metal Plating] A molded product of a square plate which was pretreated or only degreased was subjected to chemical copper plating with a thickness of 1 μm by the following steps.

Conditioning: Conditioner SP (150 ml / l, 40 ° C., 4 min) Catalyst: Catalyst C (40 ml / l, 23 ° C., 4 m
in) Activation: sulfuric acid (100 ml / l 40 ° C., 4 min) Chemical copper plating: OPC-copper H

The above-mentioned conditioner SP, catalyst C, and OPC-copper H are all manufactured by Okuno Chemical Industries Co., Ltd.

[Formation of Sputtering Film] A thin film of gold was formed on a rectangular plate compact by using a sputtering device (JFC1500) manufactured by JEOL (Argon gas pressure 1 × 10 ^−3).
Torr). The film thickness was set by the control system attached to the same device.

[Paint coating] A pre-treated or degreased square plate molded product was sprayed with an acrylic lacquer manufactured by Shinto Paint Co., Ltd. to form a coating film having a thickness of about 10 μm.

[Application of Adhesive] A molded rectangular plate was cut into a width of 10 mm, a room temperature curing type epoxy adhesive was applied to the test piece for a length of 10 mm, and another test piece was applied with the adhesive. The coated parts were overlapped and left for one day and night.

[Measurement of Adhesion] Regarding the metal-plated sample and the sample coated with the paint, JIS K5400 is used.
The adhesion was measured according to the cross-cut tape method of 1990. This is made by making 11 vertical and horizontal cuts with a knife at intervals of 1 mm (100 squares can be made), and a cellophane tape is attached to this portion and peeled off at a high speed. The state of the remaining film was scored according to the evaluation criteria of Table 8 of the same JIS and used as the degree of adhesion. That is, the larger the number, the greater the adhesion strength.

In the case of an adhesive, a test piece adhered as described above was applied with a tensile force at a speed of 50 mm / min by a tensile tester, and the load at break was taken as the adhesion.

[Evaluation of surface smoothness] With respect to the metal-plated test body, JISZ was used with a Suga Test Instruments company gloss meter.
The glossiness (60 ° / 60 °) was measured according to 8741 and used as a measure of the surface smoothness.

Example 1 A rectangular plate molded by LCP-1 was used as an Ascreen A-2.
After degreasing with 20 (Okuno Pharmaceutical Co., Ltd.), 30
It was sonicated in a 0 g / l concentration KOH aqueous solution at 50 ° C. for 10 minutes. This was subjected to chemical copper plating by the above method. The adhesion of this product is 10, and the gloss is 120%.
Met.

Comparative Example 1 Example 1 except that ultrasonic treatment in a KOH aqueous solution was omitted.
The same operation was performed. The adhesion of this product was zero.

Comparative Example 2 Example 1 except that the ultrasonic treatment conditions were 50 ° C. and 1 minute.
The same operation was performed. The adhesion of this product was zero.

Comparative Example 2 A rectangular plate molded by LCP-1 was used, and after degreasing with A-screen A-220, the method described in the above-mentioned "Journal of the Japan Adhesive Society, Vol. 26, No. 2, p. 21". Chemical copper plating was carried out according to. That is, an aqueous KOH solution having a concentration of 750 g / l was used as an etching solution at 25 ° C.
It was soaked for a minute and etched. After that, chemical copper plating was performed by the following steps of conditioning in Example 1.
The adhesiveness of this product was 10, but the glossiness was 3%.

Comparative Example 3 Chemical copper plating was carried out in the same manner as in Example 1 except that immersion was carried out in a KOH aqueous solution having a concentration of 300 g / l at 50 ° C. for 10 minutes (no ultrasonic wave was applied). The adhesion of this product was zero.

Example 2 The same procedure as in Example 1 was carried out except that LCP-2 was used instead of LCP-1. The adhesiveness of this product was 10, and the glossiness was 128%.

Example 3 Ultrasonic treatment was performed in the same manner as in Example 1, and thereafter a gold sputtering film having a coating film thickness of 500 angstrom was formed. The adhesiveness of this product was 10, and the glossiness was 95%.

Comparative Example 4 A sputtering film was produced in the same manner as in Example 3 except that the ultrasonic treatment in KOH was omitted. The adhesion of this product was zero.

Example 4 Ultrasonic treatment was carried out in the same manner as in Example 1, and a coating film was formed thereon by the method described above. The adhesiveness of this product was 10, and the glossiness was 85%.

Comparative Example 5 A coating film was formed in the same manner as in Example 4 except that the ultrasonic treatment in KOH was omitted. The adhesion of this product was zero.

Comparative Example 6 An etching treatment was applied in the same manner as in Comparative Example 3, and a coating film was formed on this by the same method as in Example 4. This product had an adhesion of 8 and a gloss of 48%.

Example 7 A rectangular plate formed by LCP-1 was used as an Ascreen A-2.
After degreasing using 20, 300g / l concentration of KOH
It was immersed in an aqueous solution at 50 ° C. for 5 minutes. This was washed with water, sonicated in 100 ml / l sulfuric acid at 40 ° C. for 5 minutes, and then chemically copper-plated in the same manner as in Example 1. This product had an adhesion of 10 and a gloss of 130%.

Comparative Example 7 After immersion in a KOH aqueous solution in Example 7, chemical copper plating was performed without ultrasonic treatment. The adhesion of this product was zero.

Example 8 The same ultrasonic treatment as in Example 1 was carried out, and then the bonding was carried out by the above method. The shear peel strength was measured by an Instron universal tensile tester and found to be 38 kg / cm ² .

Comparative Example 8 Bonding was carried out in the same manner as in Example 8, omitting only ultrasonic treatment.
The shear peel strength was 9 kg / cm ² .

[0098]

INDUSTRIAL APPLICABILITY The present invention forms a joint structure by means such as forming a metal film on the surface of a thermotropic liquid crystal resin molded article, laminating another synthetic resin, applying a paint, joining with an adhesive, or the like. In the case of using a thermotropic liquid crystal resin that has been previously ultrasonicated,
By doing so, the adhesion with other materials to be joined is improved to a practically sufficient level. In addition, this ultrasonic treatment makes it possible to use a safe drug and to perform the treatment under relatively mild conditions.

The thermotropic liquid crystal resin has mechanical strength,
It is excellent in heat resistance, dimensional accuracy, electrical characteristics, flame retardancy, moldability, etc., and molded products using this are industrially useful, but lack in appearance and are easily scratched on the surface. It has the properties of poor adhesion and low electrical conductivity. Therefore,
After the pretreatment in the present invention, a metal film, a coating film, an adhesive agent, etc. are applied, and by solving these problems, the added value of the thermotropic liquid crystal resin molded product is increased, and new application development is possible. Become.

For example, a molded product coated with a metal film of chromium, nickel, copper, gold or the like is used for automobile parts, electric / electronic parts, mechanical parts and the like. In particular, when it is used for plating an electronic circuit board, the surface smoothness of the molded product is significantly improved as compared with the conventional method, so that a finer pattern can be formed. In addition to the above-mentioned applications, the coated product can be used for tableware such as oven cook containers. In addition, thermotropic liquid crystal resin molded products can adhere well to each other and other substances, which is effective for assembling complicated products.

Claims (10)

[Claims] 1. A joint structure, wherein one surface constituting the joint is a surface of a molded article made of ultrasonically treated thermotropic liquid crystal resin. 2. The other surface constituting the joint is made of metal,
The joint structure according to claim 1, which is a surface made of any material selected from a synthetic resin, a paint, and an adhesive. 3. The joint structure according to claim 1, wherein the thermotropic liquid crystal resin contains a filler. 4. A method of joining a thermotropic liquid crystal resin, which comprises applying ultrasonic vibration to the thermotropic liquid crystal resin and then joining the same. 5. The method for joining a thermotropic liquid crystal resin according to claim 4, wherein the thermotropic liquid crystal resin contains a filler. 6. The method for joining a thermotropic liquid crystal resin according to claim 4, wherein the ultrasonic vibration is applied in a liquid. 7. The method for joining a thermotropic liquid crystal resin according to claim 6, wherein the liquid is an alkaline liquid. 8. The method for joining a thermotropic liquid crystal resin according to claim 7, wherein the liquid has a temperature of 40 ° C. or higher. 9. The thermotropic liquid crystal resin according to claim 4, wherein the material to be bonded to the thermotropic liquid crystal resin is any material selected from metals, synthetic resins, paints and adhesives. Joining method. 10. The method according to claim 4, wherein the thermotropic liquid crystal resin is a thermotropic liquid crystal polyester resin.
9. The method for joining a thermotropic liquid crystal resin according to any one of 9 above.