JP3305433B2 - Thermotropic liquid crystal resin bonding structure and bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plating and vacuum deposition of the surface of a molded article made of a thermotropic liquid crystal resin (hereinafter sometimes referred to as LCP) which is useful in the fields of electric / electronic parts, automobile parts, mechanical parts and the like. , A method such as metallizing by a method such as sputtering, or a method of laminating a film of another synthetic resin or a method of applying a paint, an adhesive, or the like, and applying a film made of LCP to a surface of a molded product made of LCP, etc. The present invention relates to a bonding structure formed by bonding and a bonding method.

[0002]

2. Description of the Related Art In recent years, LCP has been attracting attention as a new synthetic resin, and its use has been extended, and in order to functionalize and decorate a molded product, a metal coating is formed on the surface by plating, vapor deposition, sputtering, or the like. There is a demand for laminating other synthetic resins, applying a paint, joining various materials with an adhesive, and the like.

[0003] Since LCP is generally chemically stable, when a film of another material is formed on the surface of a molded article made of LCP, little chemical bonding force can be expected between the LCP and the film. Therefore, it is often necessary to pretreat the surface of the LCP molded product by some method. This includes LC
It is conceivable that the P surface is roughened (generally referred to as etching). Various methods have been proposed for this surface roughening method. For example, JP-A-62-54073
Japanese Patent Application Laid-Open Publication No. H11-163,086 discloses the use of a chromic acid mixed solution as an etching solution for pretreatment of metallizing. But,
The potassium dichromate used here has a problem of environmental pollution, and requires a great deal of cost for treating the waste liquid. This is 95% sulfuric acid, 2% potassium dichromate, 3% water
(Weight ratio), and there is a problem in handling due to the extremely high concentration.

Japanese Patent Laid-Open No. 1-98637 discloses L.
A method of blending a specific filler with CP and etching with a sulfuric acid solution is disclosed.
% Or more is required and there is a problem in handling.

[0005] When a material to be joined to an LCP molded article is a film formed on the surface and is a metal, for example, a practical method in the case of plating is described in "Journal of the Adhesion Society of Japan, Vol. 26, No. 2, p. 21 (1990) ". Here, he points out that the surface state 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 articles is that the pretreatment liquid has a problem of environmental pollution and safety and must use a high concentration and difficult to handle pretreatment liquid. That is. Another problem is that the pre-treatment is etching (meaning roughening the surface), which is intended to improve the bonding strength by mechanical anchoring effect in the joint formation, Such surface roughening treatment may inevitably impair the smoothness of the product surface.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and uses a liquid which is safe and easy to handle as a processing liquid by a simple method, and is performed under relatively mild conditions. It is an object of the present invention to provide a thermotropic liquid crystal resin bonding structure capable of forming a film of another material without impairing the surface smoothness, and a bonding method therefor.

This is further summarized below. For industrially useful molded products using LCP, a material with excellent mechanical strength, heat resistance, dimensional accuracy, electrical properties, flame retardancy, moldability, etc. Decorating or functionalizing by means such as forming a film, laminating another synthetic resin, applying a paint, or bonding with an adhesive increases the added value.

The present invention provides a method for forming a film in which the adhesion between the LCP and a film of another material is sufficiently high for practical use.

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

[0011] The appearance of a product coated with another material is excellent, and an LCP molded product having high commercial value is provided.

[0012]

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

[0013] That is, the present invention relates to a bonding structure characterized in that one surface constituting the bonding is a surface of a molded product made of a thermotropic liquid crystal resin subjected to ultrasonic treatment.

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

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

The liquid crystal polymer includes, for example, liquid crystalline polyester, liquid crystalline polycarbonate, liquid crystalline polyesterimide, etc., specifically, (whole) aromatic polyester, polyesteramide, polyamideimide, polyestercarbonate, polyazomethine, etc. No.

A thermotropic liquid crystal polymer generally has an elongated and flat molecular structure, has high rigidity along the long chain of the molecule, and has a plurality of chain-extended bonds in either a coaxial or parallel relationship. .

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

Representative examples of the monomers 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. (D) (D ₁ ) aromatic dithiol, (D ₂ ) aromatic thiophenol, (D ₃ ) aromatic thiol carboxylic acid compound, (E) aromatic hydroxy Examples thereof include at least one of an amine and an aromatic diamine compound.

Although these may be constituted independently,
Many are (A) and (C), (A) and (D), (A),
(B) and (C), (A), (B) and (E), or (A), (B), (C) and (E), and the like.

The aromatic dicarboxylic acid compound (A) includes 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,
Alkyl, alkoxy or halogen-substituted aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid, ethoxy terephthalic acid and the like.

(B) The aromatic hydroxycarboxylic acid compounds include aromatic hydroxycarboxylic acids 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-substituted 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.

(C) As the aromatic diol, 4,4 '
-Dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, hydroquinone, resorcinol, 2,6-naphthalenediol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, Aromatic diols such as 3,3'-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) methane, or chlorohydroquinone And alkyl-, alkoxy- or halogen-substituted aromatic diols such as methylhydroquinone, t-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcin and 4-methylresorcin. That.

(D ₁ ) As aromatic dithiol, benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, 2,7-naphthalene-dithiol And the like.

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

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

(E) As aromatic hydroxyamine and aromatic diamine compounds, 4-aminophenol, N-
Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine,
N, N'-dimethyl-1,4-phenylenediamine, 3
-Aminophenol, 3-methyl-4-aminopheno-
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'-diaminodiphenyl ether (oxydianiline) and the like.

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

Of the thermotropic liquid crystal polyesters suitable for use in the present invention in terms of molecular weight,
200,000, preferably about 4000-100,000. The molecular weight can be measured, for example, by measuring the terminal groups of the compressed film by infrared spectroscopy. GPC, a general measurement method involving solution formation
It can also be.

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

[0031]

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A particularly preferred aromatic polyester of the present invention is a polyester represented by the following formula (2) having a repeating unit having a structure derived from each of 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 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 a repeating unit having a structure derived from two kinds of compounds, p-hydroxybenzoic acid and hydroxynaphthalenecarboxylic acid.

[0033]

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[0034]

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

The thermotropic liquid crystal resin alone can constitute 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, the use of a material containing an inorganic filler improves the bonding strength, and such a mode is a preferable mode.

The inorganic filler is not particularly limited, and examples thereof include fillers having a fibrous, granular, or flake shape. Examples of the fibrous filler include glass fiber, carbon fiber, alumina fiber, gypsum fiber, shirasu fiber, asbestos fiber, metal fiber, and various whiskers.

A particularly preferred inorganic filler in the present invention is a filler having a powdery / granular shape. By using this filler, not only can a molded article having a smooth surface be obtained, but also the adhesion to a coating of another material can be obtained. Power improves. If the aspect ratio is 10 or less, the shape does not necessarily have to be spherical,
Irregular or flat shapes may be used.

As the powder and 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 like a glass balloon, a shirasu balloon, a carbon balloon, a hollow glass fiber, etc., for example.

The above-mentioned fillers can be used in combination of two or more kinds, and if necessary, may be used after being pretreated with a silane-based or titanate-based coupling agent.

These fillers are preferably added in an amount of 5 to 80% by weight, more preferably 10 to 70% by weight. If the content is less than 5% by weight, the effect of improving the strength and workability described above may not be exhibited, and the adhesion of the coating may be insufficient. If it exceeds 80% by weight, the mechanical strength and the like are undesirably reduced.

A so-called L obtained by mixing other polymers
It can be used as a CP polymer blend or an LCP polymer alloy. Other resins that can be blended include polyethylene, polypropylene, polybutene, polyolefin resins or elastomers such as polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, polyester resins or elastomers such as polyethylene naphthalate, aliphatic, and the like. Examples include various engineering plastics such as polyamide resin or elastomer such as nylon and aromatic nylon, polystyrene resin or elastomer, polycarbonate resin, fluorine resin, polysulfone resin, polyoxymethylene resin, polyphenylene sulfide resin, and polyketone resin.

In addition, an antioxidant and a heat stabilizer (for example, hindered phenols, hydroquinones, phosphites, and thioethers) and a light stabilizer (thermotropic liquid crystal resin) as long as the object of the present invention is not impaired. For example, benzophenones, benzotriazoles, hindered amines, salicylates, resorcinols), lubricants and release agents, coloring agents including dyes and pigments (eg, carbon black, titanium white, phthalocyanine, cadmium sulfide), flame retardants, plasticizers Ordinary additives such as an antistatic agent can be blended to impart predetermined characteristics.

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

In the present invention, before forming a coating of metal or the like or a resin laminate on the molded article, that is, before forming a bonding structure, it is preferable to use a suitable medium such as a gas or a liquid for transmitting ultrasonic waves. It is an essential requirement that a pretreatment is performed by applying ultrasonic vibration to the surface of the molded body in a liquid, and a molded product subjected to such treatment is used.

The apparatus for applying ultrasonic vibration is not particularly limited as long as it preferably has a structure to which ultrasonic waves can be applied via a liquid. Such devices include a piezoelectric vibrator using quartz or the like, an electrostrictive vibrator using barium titanate or the like, or a magnetostrictive vibrator using nickel or ferrite or the like. There is a type which gives a vibration to a container by ultrasonic waves having a frequency of about 50 KHz. A sound wave propagates from a container to a liquid, and the ultrasonic wave is applied to a molded article through the liquid. Such ultrasonic cleaning devices have various outputs ranging from tens to hundreds of watts depending on the shape and size of the object to be applied, to industrial devices of 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 placed in the container of the ultrasonic cleaning apparatus, and if necessary, a degreased thermotropic liquid crystal resin molded product is immersed in the container. Is applied.

In this case, the temperature at the time of applying the voltage may be room temperature, but by heating to a temperature not lower than 40 ° C. and not exceeding the boiling point of the liquid, the treatment effect may be improved. The frequency of the applied ultrasonic wave is 20 KHz or more, preferably 2 kHz.
5 kHz or more. The upper limit of the frequency is not particularly limited. However, since an ultrasonic wave having a too high frequency is expensive in terms of the apparatus, it is usually 10 MHz or less.

The intensity of the ultrasonic wave is not particularly limited, but may be generally 0.1 W / cm ² or more in a liquid. Although the upper limit value is not particularly limited, too high output usually results in an output of 100 W / cm ² or less because phenomena such as a rise in liquid temperature are observed.

In the present invention, the application time of the ultrasonic wave is preferably 2 minutes or more, and more preferably 5 minutes or more, in order to sufficiently exert the adhesion to the film. Before subjecting the synthetic resin electronic parts etc. to the assembly process after molding,
Ultrasonic waves may be applied in an organic solvent such as chlorofluorocarbon, but this is usually performed within 1 minute at room temperature because of the purpose of degreasing. Under such conditions, the effect of the pretreatment of the present invention may be reduced. Not expressed.

The liquid used in the ultrasonic treatment in the present invention is not particularly limited, and may be an alkaline aqueous solution, an acidic aqueous solution,
Organic solvents, water and the like are mentioned as examples. Examples of the alkaline aqueous solution include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, aluminum hydroxide,
An aqueous solution of an alkaline substance such as barium hydroxide or ammonia may be used, and two or more alkaline substances may be used in combination. Acidic aqueous solutions include sulfuric acid, nitric acid,
An aqueous solution of an acidic substance such as hydrochloric acid, chromic acid, and dichromic acid can be used, and two or more acidic substances can be used in combination. Examples of the organic solvent include aliphatic hydrocarbons such as toluene, xylene, and tetralin, aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as decalin, ethylene tetrafluoride, ethylene trifluoride, tetrachloroethane, and trichloroethane. , Trichloroethylene, halogenated hydrocarbons such as carbon tetrachloride, ethyl acetate, esters such as butyl acetate, acetone, ketones such as 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, fluorophenol compounds such as pentafluorophenol, dimethylformamide, dimethyl sulfoxide and the like. . These can also be used in combination of two or more. Further, the organic solvent can be mixed with an alkaline aqueous solution or an acidic aqueous solution.

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

The concentration of the alkaline or acidic aqueous solution can be lower than that used in ordinary etching. The amount of the alkaline or acidic substance dissolved in water is preferably at least 100 g / l, more preferably at least 200 g / l. 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 generally, when the concentration is high, the smoothness of the coating may be impaired.
/ L is preferred. This concentration is related to the sonication time described later, and a relatively high concentration is preferable when the time is short, and a relatively low concentration is preferable when the time is long.

Prior to the ultrasonic treatment, the effect may be further increased by dipping in a liquid different from the treatment liquid. 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, a good result can be obtained by immersing it in an acidic or alkaline aqueous solution in advance.

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

Although there are various methods for forming a metal film, methods such as chemical plating, electroplating, sputtering, and vapor deposition are generally used.

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

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

The sputtering method is, for example, 1 × 10 ⁻³ to
A high voltage of, for example, 10,000 volts or more is applied between the positive and negative electrodes in a high vacuum of 2 × 10 ⁻⁴ Torr to generate a glow discharge, and thereby the cathode metal is scattered. The scattered metal is a thermotropic liquid crystal. It deposits on the surface of a resin molded product to form a metal coating. The coexistence of an inert gas such as argon is also performed. There are many types of metals, including copper, gold, chromium, aluminum, etc.
A coating 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 Torr.
Under a high vacuum of about r, the deposition material is heated, and a metal film is formed on the surface of the molded body by vapor-depositing a metal on the surface of the molded product, which is the substrate surface. 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 article in a state close to a thermodynamic equilibrium state to form these films. How to Examples of the deposited substance include metals such as boron, oxides such as silica and alumina, carbides such as silicon carbide, nitrides such as silicon nitride, and the like.

Alternatively, an ion plating method or the like may be used in which the evaporated particles of the base material from the evaporation source are ionized in plasma under a high vacuum, and the ions are adhered to coat the particles. As a method for generating plasma, there are a DC excitation method in which a DC electric field is applied and a high-frequency excitation method in which a high-frequency electric field is applied. Either method can be adopted.

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

After the ultrasonic treatment, if a conventionally known plastic coating material is applied to the thermotropic liquid crystal resin molded product, the adhesive strength of the coating material is improved. The paint for painting the thermotropic liquid crystal resin molded product is not particularly limited,
Any paint 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 used. The coating method of these paints can also be a conventionally known coating method.For example, after ultrasonically treated thermotropic liquid crystal resin molded article, after appropriate degreasing and washing, spray coating, brush coating and the like are used in general methods. Applied. In general, the paint film thickness is a dry film thickness,
It is in the range of 0.1 to 100 μm.

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

Alternatively, the thermoplastic resin can be joined to the thermotropic liquid crystal resin molded article by pressing a molten thermoplastic resin onto a thermotropic liquid crystal resin molded article, for example, a film or sheet, which has been subjected to ultrasonic treatment in advance, and then cooling. . Such a thermoplastic resin is not particularly limited, for example, polyethylene terephthalate, polybutylene terephthalate, polyester-based resin or elastomer such as polyethylene naphthalate, aliphatic nylon,
Synthetic resins exemplified for blending or alloying with the above-mentioned thermotropic liquid crystal resin such as polyamide resin such as aromatic nylon or elastomer or the like can be used. As a method of melt-compression bonding, a method of extruding a molten thermoplastic resin from a T-die onto a thermotropic liquid crystal resin molded product, for example, a film or a sheet, which has been subjected to ultrasonic treatment in advance, and a method of pressing with a hot press, or the like Can be adopted. By doing so, a laminate in which the thermoplastic resin is laminated is obtained. By performing the 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 a repeating structural unit derived from p-hydroxybenzoic acid / terephthalic acid / biphenol / isophthalic acid was prepared (optical anisotropy using a polarizing microscope equipped with a hot stage). Was observed, and showed an optical anisotropy in a molten state at 340 ° C. or higher.)

On the other hand, 50% by weight of granular calcium carbonate (average particle size: 5 μm) was blended, 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-mentioned thermotropic liquid crystal polyester resin, and kneaded and granulated using a twin screw extruder.

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

[Ultrasonic treatment] As an ultrasonic treatment device, VS-150 manufactured by Iuchi Seieido Co., Ltd. was used. The processing conditions, the processing solution, and the like are described in Examples below.

[Metal Plating] The preform-treated or degreasing-treated square plate was subjected to chemical copper plating with a thickness of 1 μm by the following process.

Conditioning: Condilizer SP (150 ml / l, 40 ° C., 4 min) Catalyst: Catalyst C (40 ml / l, 23 ° C., 4 m)
in) Activation: sulfuric acid (100 ml / 140 ° C., 4 min) Chemical copper plating: OPC-Kappa H

The condilizer SP, catalyst C and OPC-copper H are all manufactured by Okuno Pharmaceutical Company.

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

[Coating of Paint] An acrylic lacquer manufactured by Shinto Paint Co., Ltd. was sprayed on the molded product of the square plate which had been subjected to the pretreatment or subjected to only the degreasing treatment to form a coating film having a thickness of about 10 μm.

[Applying Adhesive] A rectangular plate was cut to a width of 10 mm, a room-temperature-curable epoxy-based adhesive was applied to the test piece for a length of 10 mm, and another test piece was coated with the adhesive. The coated portions were overlapped and left for one day.

[Measurement of Adhesion Degree] Regarding the sample plated with metal and the sample coated with paint, JIS K5400
The adhesion was measured according to the 1990 cross cut tape method. For this, eleven vertical and horizontal cuts are made with a knife at intervals of 1 mm (100 squares are formed), and a cellophane tape is attached to this portion and peeled off at a high speed. The state of the remaining film was scored based on the evaluation criteria shown in Table 8 of the same JIS, and used as the degree of adhesion. That is, a larger number indicates a higher adhesion strength.

In the case of an adhesive, the test piece bonded as described above was subjected to a tensile force at a speed of 50 mm / min by a tensile tester, and the load at the time of breaking was taken as the degree of adhesion.

[Evaluation of Surface Smoothness] The metal-plated test piece was measured using a JISZ Glossmeter manufactured by Suga Test Instruments Co., Ltd.
Gloss (60 ° / 60 °) was measured according to 8741 and used as a measure of surface smoothness.

Example 1 A square plate formed by LCP-1 was applied to A-screen A-2.
After degreasing using 20 (manufactured by Okuno Pharmaceutical), 30
Ultrasonic treatment was carried out at 50 ° C. for 10 minutes in an aqueous KOH solution having a concentration of 0 g / l. This was subjected to chemical copper plating by the above method. This product has an adhesion of 10 and a gloss of 120%.
Met.

Comparative Example 1 Example 1 was repeated except that the ultrasonic treatment in the KOH aqueous solution was omitted.
The same operation as described above was performed. The degree of adhesion of this product was 0.

Comparative Example 2 Example 1 was repeated except that the ultrasonic treatment was performed at 50 ° C. for 1 minute.
The same operation as described above was performed. The degree of adhesion of this product was 0.

Comparative Example 3 A square plate formed by LCP-1 was used and degreased by A-screen A-220, followed by the method described in the aforementioned “Journal of the Adhesion Society of Japan, Vol. 26, No. 2, p. 21”. Chemical copper plating according to That is, a KOH aqueous solution having a concentration of 750 g / l is used as an etching solution,
It was immersed for minutes and etched. Thereafter, chemical copper plating was performed by the steps following the conditioning of Example 1.
The adhesion was 10 but the gloss was 3%.

Comparative Example 4 Chemical copper plating was carried out in the same manner as in Example 1 except that it was immersed in a 300 g / l KOH aqueous solution at 50 ° C. for 10 minutes (no ultrasonic wave was applied). The degree of adhesion of this product was 0.

Example 2 An experiment was carried out in the same manner as in Example 1 except that LCP-2 was used instead of LCP-1. This had an adhesion of 10 and a gloss of 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 Å was formed thereon. This had an adhesion of 10 and a gloss of 95%.

Comparative Example 5 A sputtering film was formed in the same manner as in Example 3 except that the ultrasonic treatment in KOH was omitted. The degree of adhesion of this product was 0.

Example 4 Ultrasonic treatment was performed in the same manner as in Example 1, and a coating film was formed thereon by the above-described method. This had an adhesion of 10 and a gloss of 85%.

Comparative Example 6 A coating film was formed in the same manner as in Example 4 except that the ultrasonic treatment in KOH was omitted. The degree of adhesion of this product was 0.

Comparative Example 7 An etching treatment was performed in the same manner as in Comparative Example 4, and a coating film was formed thereon in the same manner as in Example 4. This had an adhesion of 8 and a gloss of 48%.

Example 7 A square plate molded by LCP-1 was used as an A-screen A-2.
After degreasing treatment using KOH 20, KOH at a concentration of 300 g / l
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 subjected to chemical copper plating in the same manner as in Example 1. The adhesion was 10 and the gloss was 130%.

Comparative Example 8 In Example 7, after immersion in a KOH aqueous solution, chemical copper plating was performed without ultrasonic treatment. The degree of adhesion of this product was 0.

Example 8 The same ultrasonic treatment as in Example 1 was performed, and then subjected to the above-mentioned bonding. The shear peel strength was 38 kg / cm ^{2 as} measured by an Instron universal tensile tester.

Comparative Example 9 Bonding was performed in the same manner as in Example 8 except that only the ultrasonic treatment was omitted.
The shear peel strength was 9 kg / cm ² .

[0098]

According to the present invention, a joint structure is formed by means such as forming a metal film on the surface of a thermotropic liquid crystal resin molded product, laminating another synthetic resin, applying a paint, or joining with an adhesive. At the time, using a thermotropic liquid crystal resin that has been subjected to ultrasonic treatment in advance,
By doing so, the adhesion to 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.

Thermotropic liquid crystal resin has mechanical strength,
It is excellent in heat resistance, dimensional accuracy, electrical properties, flame retardancy, moldability, etc., and molded products using it are industrially useful, but lack in aesthetic beauty, the surface is easily scratched, It has the properties of poor adhesion and low electrical conductivity. Therefore,
After applying the pretreatment in the present invention, a metal film, a coating film, an adhesive, etc. are applied, and by solving these problems, the added value of the thermotropic liquid crystal resin molded product is increased, and new applications can be developed. Become.

For example, molded articles provided with a metal coating such as chromium, nickel, copper, and gold are used for automobile parts, electric / electronic parts, mechanical parts, and the like. In particular, when used for plating an electronic circuit board, the smoothness of the surface of the molded product is greatly improved as compared with the conventional method, so that a finer pattern can be formed. The coated product can be used for tableware such as oven cook containers in addition to the above-mentioned applications. In addition, good adhesion between thermotropic liquid crystal resin molded products and other substances is possible, and it is effective in assembling complicated products.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-33838 (JP, A) JP-A-2-253949 (JP, A) JP-A-4-283245 (JP, A) JP-A-3-283 146544 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 65/00-65/82 C08J 5/12

Claims (10)

(57) [Claims] Claims: 1. A surface treatment liquid in which one of surfaces constituting a joint is a surface treatment liquid
And satisfies at least two of the following four conditions.
The surface of the molded article der consisting wholly aromatic liquid crystal polyester resin containing no ultrasonic washed bromine compound under conditions in which the foot
The other is selected from metals, synthetic resins, paints and adhesives
Junction structure, characterized in that it is either to be. (A) the temperature of the surface treatment solution is in the range of 40 ° C. to the boiling point, and (B) the frequency of the applied ultrasonic wave is 20 KHz to 10 MH.
z: (C) The intensity of the ultrasonic wave is 0.1 W / cm ^{2 to} 100 W / c
m ² , and (D) ultrasonic application time is 2 minutes or more. 2. One of the surfaces constituting the bonding is a surface treatment liquid.
And satisfies at least two of the following three conditions.
The surface of a molded article made of a wholly aromatic liquid crystal polyester resin containing no bromine compound which has been subjected to ultrasonic cleaning for at least 2 minutes under the conditions to be added , and the other is metal, synthetic resin, paint and adhesive.
A joining structure characterized by being one selected from the following . (A) the temperature of the surface treatment liquid is in the range of 40 ° C. to the boiling point; (B) the frequency of the applied ultrasonic wave is 20 KHz to 10 MH
z, and (C) the intensity of the ultrasonic wave is 0.1 W / cm ^{2 to} 100 W / c.
range of m ^2. 3. The method according to claim 1, wherein the wholly aromatic liquid crystal polyester resin is p
A liquid crystal polyester resin having a repeating unit structure derived from at least one compound selected from hydroxybenzoic acid and (a) phthalic acid, (b) biphenol and (c) hydroxynaphthoic acid. Item 3. The bonding structure according to Item 1 or 2 . 4. The bonding structure according to claim 1, wherein the wholly aromatic liquid crystal polyester resin contains a filler. 5. A wholly aromatic liquid crystal polyester resin molded article containing no bromine compound is immersed in a surface treatment liquid, and
Ultrasonic washing under conditions that satisfy at least 2 of the above 4 conditions
After cleaning, the surface to be treated and metal, synthetic resin, paint and
A method of bonding a wholly aromatic liquid crystal polyester liquid crystal resin, which is bonded to any one selected from adhesives . (A) the temperature of the surface treatment solution is in the range of 40 ° C. to the boiling point, and (B) the frequency of the applied ultrasonic wave is 20 KHz to 10 MH.
z: (C) The intensity of the ultrasonic wave is 0.1 W / cm ^{2 to} 100 W / c
m ² range, and (D) ultrasonic application time is 2 minutes or more
Up. 6. A wholly aromatic liquid crystal polyester resin containing no bromine compound is immersed in a surface treatment solution, and
Ultrasound for at least 2 minutes under conditions that satisfy at least 2
After cleaning, the surface to be treated and metal, synthetic resin, paint and
And a bonding method for a wholly aromatic liquid crystal polyester liquid crystal resin. (A) the temperature of the surface treatment solution is in the range of 40 ° C. to the boiling point, and (B) the frequency of the applied ultrasonic wave is 20 KHz to 10 MH.
z, and (C) the intensity of the ultrasonic wave is 0.1 W / cm ^{2 to} 100 W / c.
range of m ^2. 7. The method according to claim 7, wherein the wholly aromatic liquid crystal polyester resin is p
A liquid crystal polyester resin having a repeating unit structure derived from at least one compound selected from hydroxybenzoic acid and (a) phthalic acid, (b) biphenol and (c) hydroxynaphthoic acid. Item 7. The method for bonding a wholly aromatic liquid crystal polyester liquid crystal resin according to item 5 or 6. 8. The method for bonding a wholly aromatic liquid crystal polyester resin according to claim 5, wherein the wholly aromatic liquid crystal polyester resin contains a filler. 9. An alkaline aqueous solution as the surface treatment liquid
The method for bonding a wholly aromatic liquid crystal polyester resin according to any one of claims 5 to 8 , comprising: 10. One liter of the surface treatment liquid was applied.
100 g or more alkali compound dissolved alkali
10. A liquid according to any one of claims 5 to 9, which comprises a neutral aqueous solution .
2. The method for bonding a wholly aromatic liquid crystal polyester resin according to claim 1 .