JPH01176080A - Plating pretreatment of liquid crystal polyester resin molded article - Google Patents

Abstract

PURPOSE:To uniformly impart a catalyst and to improve the plating property by dipping the title molded article in a specified alkaline soln. to rough the surface, and then treating the article with an aq. soln. contg. a surfactant. CONSTITUTION:A resin composition consisting of the hot-workable polyester (expressed liq. crystal polyester hereunder) capable of forming an anisotropic molten phase and contg. 5-80% of >=1 kind of filler selected from a group II element of the periodic table, its oxide and sulfate, elements such as Al and Si, or their oxides is used for the molded article. The article is dipped in an aq. soln. contg. >=20% oxide of an alkali (earth) metal to rough the surface, and then dipped in the aq. soln. of an amphoteric surfactant to activate the roughed surface. In addition, the amphoteric surfactant has >=1 cationic or anionic functional group in its molecular structure, and belongs to an aminocarboxylate type, a carboxybetaine type, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for pre-plating a molded article of melt-processable polyester (hereinafter simply referred to as "liquid crystalline polyester") capable of forming an anisotropic melt phase.

More specifically, the present invention relates to a pretreatment method for efficiently applying plating to a liquid crystalline polyester resin molded product having excellent heat resistance and moldability.

[Conventional technology and its problems]

Unlike generally known thermoplastic polyesters such as polybutylene terephthalate and polyethylene terephthalate, liquid crystalline polyester is made of a rigid polymer, and its molecular chains are difficult to bend and maintain a rod shape even in the molten state. It has little entanglement, is oriented in one direction when subjected to a slight shear stress, and exhibits so-called liquid crystallinity, which means that it exhibits crystallinity even in liquid form.

Such liquid crystalline polyester is a general polyester resin that does not exhibit liquid crystallinity (such as polybutylene terephthalate, polybutylene terephthalate, etc.).
It is chemically more stable than polyethylene terephthalate (e.g., polyethylene terephthalate), and the surface roughening etching liquid used for general polyester cannot be applied as is. Furthermore, even if the surface is roughened, its activity is insufficient for the catalyst solution prepared for plating, and subsequent electroless plating is difficult to adhere to, and no satisfactory method is known yet.

[Means for Solving the Problems] The present inventors took advantage of the thermally beneficial characteristics of liquid crystalline polyester, such as its dust resistance, and chemically modified the surface of the liquid crystalline polyester without impairing its physical or chemical properties. As a result of extensive research into a plating pretreatment process that makes it active and enables the adhesion of a catalyst that is essential in the plating process to the resin surface, we found that after roughening the surface by immersing it in a specific alkaline solution, a specific surface activity The inventors have discovered that it is possible to uniformly apply a catalyst by treating with an aqueous solution containing a catalyst, leading to the present invention.

The specific surfactant used in the present invention has one or more cationic functional groups and anionic functional groups in its molecular structure, and is an amphoteric surfactant containing the following structure. 3) Those belonging to the aminocarboxylate type -NH2-COD; 4) Imidazoline-derived.

More preferably, it is near neutral (weakly acidic) with the following structure.
Aminocarboxylate type R-N)I-(C
H2), CDDH (R: CI2~CI8+ 11=l~
2) is desirable.

The reason why an amphoteric surfactant exhibits an effective catalyst-imparting effect on a liquid crystalline polyester molded article after surface roughening is presumed to be as follows.

In other words, before surface roughening, the surface of liquid crystalline polyester has low surface tension and poor water wettability, similar to general resin molded products, so it is necessary to add Pd-3n colloidal catalyst, which is essential for electroless plating. Can not. Even if a highly water-soluble surfactant is used to lower the surface tension of water and make the surface hydrophilic, the catalyst only temporarily attaches to the surface and quickly comes off. When immersed in a specific alkaline aqueous solution, hydrolysis occurs on the surface of liquid crystalline polyester, forming active polar groups on the surface, and in the case of filler-added liquid crystalline polyester, the surface of the molded product becomes rougher. The tension increases and the surface becomes uniformly wet. Normally, when the surface becomes hydrophilic in this way, Pd-3n colloid, which is a catalyst for stable plating in the acidic state of the catalyst solution, often adheres easily with the help of the polarity of the resin surface. . However, in the case of liquid crystalline polyester, due to its molecular structure,
Catalyst adsorption is insufficient and it is not suitable for plating as it is.

When we considered the application of surfactants, we found that nonionic surfactants and anionic surfactants were not effective in improving the adhesion of catalysts, and cationic surfactants were effective in adsorbing catalysts, but Since it does not have sufficient adsorption power for liquid crystalline polyester, the plating surface tends to become pocked.

On the other hand, the anionic functional group of the amphoteric surfactant of the present invention is
It easily adsorbs to the polar groups on the surface of the roughened liquid crystalline polyester, and the adsorbed surfactant acts as a cationic surfactant in the acidic catalyst of the catalyst solution, so it easily adsorbs the catalyst. It is presumed that this facilitates the adsorption of the catalyst onto the resin surface.

Among the amphoteric surfactants, aminocarboxylic acid salts in particular caused precipitation near the isoelectric point, and the above effect was further promoted, resulting in good results.

The amphoteric surfactant aqueous solution of the present invention can be treated by, for example, immersing a molded article in this aqueous solution, but it is also possible to use other operations such as spraying or coating with this aqueous solution. Good too.

The alkaline aqueous solution that is the etching treatment liquid in the present invention is an aqueous solution whose main component is an alkali metal hydroxide or an alkaline earth metal hydroxide, and includes sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. These are aqueous solutions of alkali metal hydroxides, and aqueous solutions of alkaline earth metal hydroxides such as strontium hydroxide and barium hydroxide. A preferred aqueous alkaline solution is an aqueous potassium hydroxide solution. The alkaline aqueous solution further dissolves the surface decomposition product of the liquid crystalline polyester and contains an organic solvent soluble in the alkaline aqueous solution, such as alconopetetrahydrofuran such as methyl alcohol, ethyl alcohol, isopropyl alcohol/L/, and isobutyl alcohol. One or two selected from among furan compounds, nitrogen compounds such as ethylamine, dimethylamine, trimethylamine, propylamine, aniline, pyridine, and formamide, and aromatic halogenated hydrocarbons such as chlorobenzene and O-dichlorobenzene.
It can be used as a composite liquid by adding more than one type of solvent.

In addition, when etching a liquid crystalline polyester molded product with such an aqueous solution, optimal conditions for immersion in the etching solution are searched and selected as appropriate depending on the composition of the etching solution. Oxide 20-6
A 0% by weight aqueous solution is used at 30-80°C for 3-120 minutes, preferably a 40-50% by weight aqueous hydroxide solution is used at 40-60°C for 10-30 minutes. As an example of particularly preferable treatment conditions, treatment with an aqueous solution of about 45% by weight of potassium hydroxide at 60° C. for about 30 minutes is suitable.

In order to further improve the plating properties of the liquid crystalline polyester molded product used in the present invention, elements of group I of the periodic table and their oxides, sulfates, phosphates, silicates, or aluminum, silicon, tin, It is preferable that one or more inorganic fillers selected from the group consisting of lead, antimony, and bismuth elements and their oxides are blended.

Oxides of elements in group ■ of the periodic table include magnesium oxide,
These are compounds such as calcium oxide, barium oxide, zinc oxide, etc. Phosphates are compounds such as magnesium phosphate, calcium phosphate, barium phosphate, zinc phosphate, magnesium birophosphate, calcium pyrophosphate, etc. are compounds such as magnesium sulfate, calcium sulfate, and barium sulfate, and silicates include magnesium silicate, calcium silicate, aluminum silicate, kaolin,
These are compounds such as talc, clay, diatomaceous earth, and wollastonite, with phosphates being particularly preferred.

In addition to the above-mentioned inorganic fillers, one or more selected from the group consisting of amphoteric metal elements such as aluminum, silicon, tin, lead, antimony, and bismuth, or oxides of these elements are also preferable.

The blending amount of these inorganic fillers is 0 to 80% by weight, preferably 10 to 80% by weight based on the total amount of the liquid crystalline polyester resin composition.
It is 70% by weight. If these fillers are not included, uneven flow marks may occur on the surface of the molded product.
Furthermore, when an adhesive tape is applied to the surface of a molded article and then peeled off, a thin film may easily peel off, and surface-treated articles tend to have uneven etching. - On the other hand, if it exceeds 80% by weight, the fluidity of the resin will decrease, making it impossible to obtain a molded product with a good surface, causing roughness on the surface due to etching, and at the same time reducing the mechanical strength of the molded product. Undesirable. In addition, the particle size of the inorganic filler is an average particle size of 0.
in the range of 0.01 to 100 μm, preferably 0.1 to 30 μm
1, more preferably 0.5 to 10 μm. 0.
If it is less than 100 μm, aggregates tend to form on the surface of the molded product due to poor dispersion, and if it exceeds 100 μm, the roughness of the surface after etching becomes large and a good appearance cannot be obtained.

Various methods can be used to blend these inorganic fillers into the liquid crystalline polyester, but it is preferable to use a melt-kneading method using an extruder to uniformly knead them prior to molding.
Dispersion is preferred.

The liquid crystalline polyester in the present invention is a melt-processable polyester, and has the property that polymer molecular chains are regularly arranged in parallel in a molten state. The state in which the molecules are arranged in this way is often called the liquid crystal state or the nematic phase of liquid crystal materials. Such polymer molecules are generally elongated, oblate, fairly rigid along the long axis of the molecule, and have multiple chain extensions, usually in either coaxial or parallel relationships. Consisting of

The nature of the anisotropic melt phase can be confirmed by conventional polarization testing using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by observing a molten sample placed on a Leitz hot stage at 40x magnification under a nitrogen atmosphere using a Leitz polarizing microscope. The polymer is optically anisotropic. That is,
Transmits light when examined between orthogonal polarizers.

If the sample is optically anisotropic, polarized light will pass through it even if it is at rest.

Constituent components of the polymer that forms the anisotropic melt phase as described above include: - Consisting of one or more of aromatic dicarboxylic acids and alicyclic dicarboxylic acids - Aromatic diols, alicyclic diols, and aliphatic diols ■ Consisting of one or more aromatic hydroxycarboxylic acids ■ Consisting of one or more aromatic thiol carboxylic acids ■ One of aromatic dithionope aromatic thiol phenol
Polyesters consisting of one or more of aromatic hydroxyamines and aromatic diamines and forming an anisotropic melt phase are polyesters consisting of ■)■ and ■■) Polyester consisting of only ■ Polyester consisting of ■) ■, ■ and ■ ■) Polythiol ester consisting only of ■ ■) Polythiol ester consisting of ■ and ■ ■) Polythiol ester consisting of ■ and ■ ■) ■ and ■ It is a polyester that forms an anisotropic melt phase composed of a combination of polyester amide consisting of ■), ■, polyester amide consisting of ■, and ■.

Furthermore, although not included in the above combination of ingredients,
Polymers that form an anisotropic melt phase include aromatic polyazomethines; specific examples of such polymers include polytrilo-2=methyl-1,4-phenylenenitrilomethylidine-1,4-72 lenethyridine); poly
trilo-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethylidine); Can be mentioned.

Furthermore, although not included in the above combination of ingredients,
Polyester carbonate is included as a polymer that forms an anisotropic melt phase. It may consist essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The polyesters (I), It), and III) and the polyesteramide (ii) above, which are polymers that form an anisotropic melt phase suitable for use in the present invention, contain functional groups that form the required repeating units by condensation. It can be produced by various ester formation methods that allow the organic monomer compounds that are present to react with each other. For example, the functional groups of these organic monomer compounds may be carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides, amine groups, and the like. The above organic monomer compound is
The melt acidolysis method allows the reaction to occur without the presence of a heat exchange fluid. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction continues, solid polymer particles become suspended in the liquid. Vacuum may be applied to facilitate removal of by-product volatiles (eg acetic acid or water) during the final stage of condensation.

Additionally, slurry polymerization methods can also be employed to form liquid crystalline polyesters suitable for use in the present invention.

In this process, a solid product is obtained in suspension in a heat exchange medium.

Liquid crystalline polymers suitable for use in the present invention tend to be substantially insoluble in common solvents and are therefore unsuitable for solution processing. However, as previously mentioned, these polymers can be readily processed using conventional melt processing techniques.

Liquid crystalline polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2.000 to 200.000, preferably about 10.000 to 50.00. (100, particularly preferably from about 20,000 to 25,000; on the other hand, suitable fully aromatic polyesteramides generally have a molecular weight of about 5
, 000 to 50,000, preferably about 10,000 to
30,000, for example 15,000 to 17,000. Such molecular weight measurements can be carried out by gel permeation chromatography as well as other standard methods of measuring polymers that do not involve solution formation, such as quantification of end groups by infrared spectroscopy on compression molded films. Alternatively, the molecular weight can be measured using a light scattering method using a pentafluorophenol solution.

The polymer exhibiting an anisotropic melt phase used in the present invention is preferably an aromatic polyester or an aromatic polyester amide, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain is also a preferred example. .

Preferred examples of the compounds constituting them are naphthalene compounds such as 2°6-naphthalene dicarboxylic acid, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, and 6-hydroxy-2-naphthoic acid; Diphenyl dicarbonate 112. Biphenyl compounds such as 4.4°-dihydroxybiphenyl, the following general formula (I), (
Compound represented by n) or (II[): (However, x: selected from alkylene (C, to C4), alkyritene, -O-, -5O-1-8O□-1-8-1-CD- Group Y (C) 12), -(n=1-4), -0(CH,
) a group selected from hO-(n: 1 to 4)) para-substituted benzene compounds such as p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminophenol, and p-phenylenediamine, and their nuclear-substituted benzene compounds (The substituent is selected from chlorine, bromine, methinopephenyl, 1-phenylethyl), isophthalic acid, resorcinol, and other meta-substituted benzene compounds.

In addition to the above-mentioned constituents, the liquid crystalline polyester used in the present invention may also be a polyalkylene terephthalate that does not show a partially anisotropic melt phase in the same molecular chain. In this case, the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned components, a more preferred example is one containing one or more compounds selected from naphthalene compounds, biphenyl compounds, and para-substituted benzene compounds as an essential component. Among the p-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferred examples.

Particularly preferred anisotropic melt phase forming polyesters for use in the present invention include repeat units containing naphthalene moieties such as 6-hydroxy-2-naphthoyl, 2,6-hydroxynaphthalene and 2,6-dicarboxynaphthalene. It contains about 10 mol% or more. Preferred polyesteramides are those containing repeating units of the naphthalene moiety described above and a moiety consisting of 4-aminophenol or 1,4-phenylenediamine.

For specific examples of the compounds constituting the above-mentioned components I) to (ii) and specific examples of polyesters forming an anisotropic melt phase that are preferable for use in the present invention, see JP-A-61-69.
His words are published in Publication No. 866.

In the present invention, in addition to the above-mentioned specific inorganic filler, various other concomitant inorganic substances may be blended for the purpose of improving various properties. It is preferable to incorporate such inorganic materials in order to obtain molded products with excellent properties such as mechanical properties, heat resistance, and dimensional stability (deformation resistance, warping). Particulate and plate-like inorganic materials are used.

Examples of fibrous fillers include glass fiber, carbon fiber, asbestos fiber, silica fiber, silica/alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, and aluminum. Examples include inorganic fibrous materials such as fibrous materials of metals such as titanium, copper, and brass.

On the other hand, granular inorganic substances include carbon black, graphite, glass beads, milled glass fibers, glass balloons, glass powder, iron oxide, metal oxides such as alumina, and other ferrites, silicon carbide, silicon nitride, boron nitride, etc. Can be mentioned.

In addition, examples of the plate-like inorganic material include mica, glass flakes, and various metal foils.

These inorganic substances can be used alone or in combination.

Particularly preferably used concomitant inorganic substances are fibrous inorganic substances, particularly glass fibers, and the amount thereof is in the range of 1 to 60% by weight, preferably 5% by weight, based on the total weight of the molded article composition.
~40% by weight.

However, it is not preferable for the total amount of the inorganic filler and the combined inorganic substance to exceed 85% by weight of the molded article composition from the viewpoint of moldability and various physical properties. In addition, the surface roughness of single-filling with only fibrous inorganic material is slightly thick (which makes it unsuitable for plating for decorative purposes.The fibrous inorganic material to be used in combination is 1 to 30μ0 in diameter and long Thickness 5 μm ~ 1
mm, preferably in the range of 10 μm to 100 μm, especially glass fiber, when combined with the inorganic filler, unexpectedly the surface of the molded article becomes more uniform and conductive circuits are formed on the molded article by plating. It has been found that the adhesion can be improved in such cases. Milled fiber glass, which is between glass fiber and fine powder glass, is particularly preferred in terms of the balance between surface roughness and mechanical properties of the material.

When using these inorganic fillers and concomitant inorganic substances, it is desirable to use a sizing agent or a surface treatment agent if necessary.

There is no adverse effect when the composition of the present invention is used in combination with a conventionally used nucleating agent.

Furthermore, the composition of the present invention may be supplemented with other thermoplastic resins within the scope of the present invention to the extent that the intended purpose thereof is not impaired.

The thermoplastic resin used in this case is not particularly limited, but examples include polyolefins such as polyethylene and polypropylene, polyacetal (homo or copolymer),
Examples include polystyrene, polyvinyl chloride, polyacrylic acid ester, and copolymers thereof, polyamide, polycarbonate, ABS, polyphenylene oxide, polyphenylene sulfide, and fluororesin. Further, two or more of these thermoplastic resins can be used in combination. .

Furthermore, known substances added to general thermoplastic resins and thermosetting resins, such as plasticizers, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, surface treatment agents, flame retardants, dyes and pigments. A lubricant, a lubricant, a crystallization accelerator (nucleating agent), etc. for improving fluidity and mold releasability can also be used as appropriate depending on the desired desired performance.

〔Effect of the invention〕

As described above, according to the plating pretreatment method for liquid crystalline polyester resin molded products of the present invention, it is possible to uniformly roughen the surface of the resin molded products, and to apply catalyst extremely uniformly, which is essential in the process. As a result, plating performance has been improved, and it has become possible to develop applications for printed wiring boards, which had been expected but could not be realized until now.

〔Example〕

The treatment method of the present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Examples 1 to 8 The liquid crystalline polyester resin A described below and the filler shown in Table 1 (wt% indicates the value relative to the total amount of the composition) were cross-dispersed and pelletized by a melt-kneading method using an extruder. After drying at 140℃ for 3 hours, the molding machine
50mm x 7 using a mold temperature controlled to ~160℃
A flat plate of Qmm x 3mm was molded.

The formed flat plate was plated according to the process described below. The etching conditions were as shown in the table.

After etching, after neutralizing the adhering residual liquid, use the amphoteric surfactant shown in Table 1 and immerse it in a 1% solution to fully activate the roughened surface to ensure uniform adhesion of the catalyst in the next step. made it easy.

After performing electroless copper plating at 25°C for 20 minutes,
After drying at ℃ for 60 minutes and leaving at room temperature for 1 day, the adhesion state of the plating was observed and the effect of the amphoteric surfactant was determined. The judgment was expressed by the number of plates on which full-surface adhesion was confirmed among the 10 plates tested.

For those with good electroless plating, electroplating is performed to check that there is no dissolution or blistering during plating, and after drying at 150℃ for 60 minutes, the adhesion state after being left at room temperature for 1 day. The electroplating property was determined by observing.

As in the above-mentioned judgment, the evaluation was based on the number of non-blistered plates out of 10 plates.

Comparative Examples 1 to 5 Flat plates prepared in the same manner as in Example 1 were plated and then treated with a surfactant under the conditions shown in Table 1, but the plating condition was not as good as when an amphoteric surfactant was used. I couldn't get it.

Examples 9 to 13 Evaluations were made in the same manner as in Example 1, except that liquid crystalline polyester A used in Example 1 was replaced with other liquid crystalline polyesters B-F.

The results are shown in Table-1.

No difference was observed under the same conditions for either base polymer.

Plating treatment method> (Water washing) 1 (Water washing) 1 (Dilute sulfuric acid) 1 The liquid crystalline polyester used in the examples has the following structural units.

=60/20/20 =70/15/15 =60/20/20 Applicant's agent Kaoru Furutani

Claims (1)

[Claims] 1. A liquid crystal characterized in that a molded article made of a melt-processable polyester capable of forming an anisotropic melt phase is surface roughened with an alkaline aqueous solution and then treated with an amphoteric surfactant aqueous solution. Plating pretreatment method for polyester resin molded products. 2. The melt-processable polyester capable of forming an anisotropic melt phase is composed of Group II elements of the periodic table and their oxides, sulfates, phosphates, silicates, or of aluminum, silicon, tin, lead, antimony, and bismuth. A patent for a liquid crystal polyester resin composition containing 5 to 80% by weight of one or more inorganic fillers selected from the group consisting of elements and their oxides, based on the total amount of the molded article composition. A method for pre-plating a liquid crystalline polyester molded article according to claim 1. 3. The method for pre-plating a liquid crystalline polyester resin molded article according to claim 1, wherein the alkaline aqueous solution is an aqueous solution containing 20% by weight or more of an alkali metal or alkaline earth metal hydroxide. 4. The liquid crystal according to any one of claims 1 to 3, wherein the amphoteric surfactant is an amphoteric surfactant selected from carboxybetaine type, sulfobetaine type, aminocarboxylate type, and imidazoline derivative type. Pre-treatment method for plating polyester molded products.