JPH02270967A - Pretreatment of electroless plating for polymer molded body - Google Patents

Abstract

PURPOSE:To make it possible to form a satisfactorily stuck plating layer having fine luster on a metathesis polymer molded body by electroless plating without carrying out pretreatment with chemicals by making the molded body hydrophilic by contact with oxygen molecules. CONSTITUTION:When the surface of a metathesis polymer molded body obtd. by simultaneously carrying out polymn. and molding in the presence of a metathesis polymn. catalyst system is electroless-plated, the surface is previously washed and brought into contact with oxygen molecules by holding in the air at ordinary temp. for a certain time or other method. By this pretreatment, the metathesis polymer rich in unsatd. bonds and allyl type tert. hydrogen is oxidized and polar groups are introduced to make the molded body moderately hydrophilic. A catalyst is then stuck to the molded body and this molded body is activated and electroless-plated. A lustrous plated surface is obtd.

Description

Detailed Description of the Invention a. Industrial Application Field The present invention relates to improved electroless plating of a polymer molded product obtained by simultaneously polymerizing and molding a metathesis polymerizable monomer in the presence of a metathesis polymerization catalyst system. This is an intermediate method. More specifically, the present invention relates to improvements in pretreatment methods for catalyst application and activation treatment in electroless plating.

b. Prior art: It is known that ring-opening polymerization of cyclic olefins can be carried out using a metathesis polymerization catalyst system. The metathesis polymerization catalyst system consists of two components, a main catalyst component and an activator component, and a monomer containing each of these two components A method has been proposed in which a reactive solution of 100% is poured into a mold immediately after mixing, and bulk polymerization is performed therein to perform polymerization and molding in one step.
(See Publication No. 29013).

According to this method, a large-sized molded product can be obtained using an inexpensive mold, so it has the possibility of being used in a wide range of applications.

However, such molded products are often required to be used with the entire or partial surface metallized depending on the intended use.

Such metallizing methods include two methods: metal vapor deposition under vacuum or a similar method, and plating.

A plating method is commonly used as a metallizing method that has a particularly metallic feel and is durable. In order to apply electroplating to plastics, which are non-conductive conductors, a method is used in which a conductive layer is first formed on the surface of the plastic by electroless plating.

Such electroless plating is conventionally carried out according to the following three steps, omitting detailed steps such as cleaning. That is,
(1) Pretreatment (2) Catalyst application and activation treatment (3) Electroless plating treatment. (1) In pretreatment, hydrophilic groups are introduced to the surface of the plastic by oxidation etc. using chemical agents. (2) Catalyst application and activation treatment Colloidal metal palladium is deposited on the plastic surface by reducing palladium chloride with stannous tin chloride, etc. In the deplating process, for example, the metal palladium t, i m is treated with a solution containing a combination of nickel chloride and a reducing agent, and then In this case, an electroless nickel plating layer is formed using the colloidal metal palladium as a core.

Using the thus obtained electroless plating layer as a conductor, electrolytic plating is generally performed in the order of copper, nickel, etc.

In the above three steps, general methods have been established for (21 and (31) regardless of the type of plastic. As for (1), the optimal method may naturally differ depending on the type of plastic. However, the most commonly used method, including ABS resin, which is most commonly used for plating, is treatment with an aqueous solution of chromic acid and sulfuric acid.

In the case of metathesis polymer molded products, it is chemically similar to ABS resin, which contains a rubber component with many unsaturated bonds, and it was expected that the same treatment method could be used as is. .

However, perhaps because ABS resin contains more unsaturated bonds than ABS resin, when the same method is applied, the surface is considerably etched, resulting in a surface with many unevenness, and after the subsequent steps, the metal will not adhere. However, it was found that the unevenness of the surface was too severe, resulting in a matte plating surface, making it impossible to obtain the original high-gloss electroless plating layer. Therefore, when the coating was made milder, it was found that the adhesion of the plating layer was not sufficient.

C1 Structure of the Invention Therefore, as a result of intensive studies to find a pretreatment for electroless plating of such a metathesis polymer resin molded product, the present inventor found that, for example, it is possible to simply leave the molded product in the air for a certain period of time. , the surface is oxidized by oxygen in the air and made hydrophilic, resulting in an additional +21. It has been discovered that by performing the step [3), it is possible to produce an electroless plated layer with excellent gloss and good adhesion.

That is, the present invention provides electroless plating on the surface of a metathesis polymer molded product obtained by molding a metathesis polymerizable monomer simultaneously with polymerization in the coexistence of a metathesis polymerization catalyst system, (1) pretreatment (2) catalyst Electroless plating characterized by using a method of making the molded product hydrophilic by bringing it into contact with oxygen molecules as a pre-treatment method before application through the electroless plating process (3). This is a pretreatment method for use.

In the present invention, as described above, at least one type of metathesis-polymerizable cyclic olefin is used as at least a part of the monomer component in the polymer molded product used for the treatment, and polymerization and molding are carried out in the presence of a metathesis polymerization catalyst system. A polymer molded product obtained by simultaneously carrying out the above steps will have at least one carbon-carbon unsaturated bond in the repeating unit of its constituent polymer components, and the treatment of the present invention can be applied thereto.

In particular, a cyclic olefin containing metasense polymerizable cyclic olefins as the main monomer, at least a part of which has two or more metathesis polymerizable cyclic olefins, and a main catalyst component and an activator component of the metathesis polymerization catalyst, respectively. , separately, together with the monomer, the reaction solution A, B
A crosslinked polymer molded product obtained by preparing two liquids, mixing the two liquids by rapid mixing such as collision mixing, and injecting the two liquids into a mold to perform polymerization and molding at the same time is preferable.

As the metathesis-polymerizable cyclic olefin group, those having a large strain are preferred because of their high polymerizability, and those having a norbornene structure are particularly preferred from the viewpoint of ease of production and polymerizability.

Suitable examples of cyclic olefins that can form crosslinked polymers include dicyclopentadiene, tricyclopentadiene, i,4,5.8-dimethano-1,4,4a.

5.8,8a-hexahydronaphthalene, 1,4,5
,8,9.10 trimethano-1,4,4a,5,8.8
a, 9.9a, 10,10a-decahydroanthracene, 1,2-adduct of 1,5-cyclooctadiene and cyclopentadiene, ethylene bisnorbornene, phenylene bisnorbornene, etc. can be used.

On the other hand, norbornene is a cyclic olefin that acts as a difunctional compound for metathesis polymerization.

5-methylnorbornene, 5-ethylidenenorbornene, 5-phenylnorbornene, vinylnorbornene, dihydrodicyclopentadiene, cyclopentadiene-methylcyclopentadiene codimer, 1,4,5.8-
Dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methyl-1,4,5°8-dimethano-1,4,4a, 5,6,7,8, 8a-Naphthalene, 6-ethylidene-1,4,5,8-
Dimethano-1,4,4a, 5,7,8.8a-octahydronaphthalene and the like can be mentioned.

In addition to the above-mentioned cyclic olefins consisting only of hydrocarbons, cyclic olefins containing different elements, that is, cyclic olefins having polar groups, can also be used as part of the monomer. Polar groups include ester groups and ether groups.

Preferred are cyano group, N-substituted imide group, halogen, and the like.

Specific examples of such copolymerizable monomers include 5-methoxycarbonylnorbornene, 5-(2-ethylhexyloxy)carbonyl-5-methylnorbornene, and 5-phenyloxymethylnorbornene.

5-cyanonorbornene, 6-diatu 1.4.5.8
-dimethano-1,4,4a, 5.6.7.8.8a-
Octahydronaphthalene, N-butylnadic acid imide.

Examples include 5.6-dichloronorbornene.

The metathesis-polymerizable polycyclic cycloolefin as described above is required to contain as few impurities as possible that would deactivate the metathesis-polymerization catalyst.

A particularly preferred monomer composition of the polymer molded product used in the present invention is a combination of 100 to 50 mol % of dicyclopentadiene remaining with a metathesis-polymerizable cyclic olefin having a norbornene structural unit as described above. I can do it.

As the catalyst component in the metathesis polymerization catalyst system used to obtain the polymer molded product used in the present invention, salts such as halides such as tungsten, rhenium, tantalum, and molybdenum are used, and tungsten compounds are particularly preferred. For example, tungsten halide.

Tungsten oxyhalide is preferable, and more specifically, tungsten hexachloride, tungsteoxychloride, etc. are preferable, and organic ammonium tungstate and the like can also be used. It is known that when such a tungsten salt compound is added directly to the monomer, cationic polymerization immediately starts, which is not preferable.

Therefore, it is preferable to use such a tungsten salt compound by first suspending it in an inert solvent such as benzene, toluene, polybenzene, etc., and solubilizing it by adding a small amount of an alcoholic compound or a phenolic compound.

Further, in order to prevent undesirable polymerization as described above, it is preferable to add about 1 to 5 mol of a Lewis base or a chelating agent to 1 mol of the tungsten compound. Such additives include acetylacetone, alkyl acetoacetate, etc. Esters.

Examples include tetrahydrofuran and benzonitrile.

Thus, the monomer solution containing the catalyst component (solution A) is
It has sufficient stability for practical use.

On the other hand, the active component in the metathesis polymerization catalyst system is preferably an organometallic compound mainly consisting of alkylated products of metals of Groups 1 to Ⅰ of the periodic table, particularly tetraalkyltin, alkylaluminum compounds, and alkylaluminum halide compounds. Specific examples include diethylaluminum chloride, ethylaluminum dichloride, trioctylaluminum 1-dioctylaluminum iodide, tetrabutyltin, tributyltin, hydride, and the like. A monomer solution (solution B) containing an activator is formed by dissolving these organometallic compounds as active agent components in the mixed monomer.

In the present invention, a polymer molded product can basically be obtained by mixing the above-mentioned solution A and solution iB, but the polymerization reaction starts very quickly if the above composition remains as it is. Hardening may occur before it has sufficiently flowed into the mold, which often poses a problem, and for this purpose it is preferable to use an activity regulator as described above.

As such regulators, Lewis bases are generally used, among which ethers, esters, nitriles, etc. are used. Specific examples include ethyl benzoate, butyl ether, diglyme, etc. Such regulators are generally added to the solution of the organometallic compound activator component. As mentioned above, when a monomer having a polar group such as Lewis space is used, it can serve as a regulator.

The amount of the metathesis polymerization catalyst system used is, for example, when a tungsten compound is used as a catalyst component, the ratio of the tungsten compound to the raw material monomer is about 1 on a molar basis.
000:1 to 15000:1, preferably 2000:1
In addition, when an alkyl aluminum is used as the active ingredient, the ratio of the aluminum compound to the raw material monomer is about 100:1 to about 2 on a molar basis.
000:1, preferably around 200:1 to about 500:1.

Further, as described above, the masking agent and the regulating agent can be appropriately adjusted and used depending on the amount of the catalyst system to be used through experiments.

In the production of the polymer molded product according to the present invention, a small amount of an active halogen compound such as trichloromethyltoluene, trichloroethyl acetate, isophthalic acid chloride, or an acid anhydride such as benzoic anhydride is added to reduce residual monomers. It can be used.

In practical use, the crosslinked polymer molded product used in the present invention has the following:
In order to improve or maintain its properties, various additives can be further added. Such additives include fillers, pigments, antioxidants, light stabilizers, flame retardants, combustible agents, polymeric modifiers, and the like. Since it is impossible to add such additives after the crosslinked polymer of the present invention is molded, it is necessary to add them to the above-mentioned raw material solution in advance when adding them.

The easiest method is to use the solution A and solution B.
Is there a method in which it is added in advance to either or both of the following? In that case, there is a certain degree of practical interference with highly reactive catalyst components, other active agent components, and acid anhydrides in the liquid. It must be something that does not react with the monomer and does not inhibit the polymerization.If the reaction is unavoidable, but if it coexists with the monomer it will not substantially inhibit the polymerization, it should not be mixed with the monomer. It is also possible to prepare a third liquid and use the mixture immediately before polymerization. In addition, in the case of solid fillers, if the two components are mixed and have a shape that can sufficiently fill the voids immediately before starting the polymerization reaction or during polymerization, it is necessary to , it is also possible to fill it up.

Reinforcements or fillers as additives are effective in improving the flexural modulus. Examples of such materials include glass fiber, mica, carbon black, and wollastonite. Those surface-treated with a so-called silane coupler can also be suitably used.

Further, it is preferable to add an antioxidant to the crosslinked polymer molded article used in the present invention, and it is desirable to add a phenol-based or amine-based antioxidant to the solution in advance. Specific examples of antioxidants include 2,6-t-butyl-P-cresol, N,N'-diphenyl-P-phenylenediamine, tetrakis methylene (3,5-di-t-butyl-4-hydroxy Cinnamate) 1Methane, etc.

Further, other polymers can be added to the crosslinked polymer molded product used in the present invention when it is in a monomer solution state. As such polymer additives, the addition of elastomers is effective in increasing the impact resistance of molded products and adjusting the viscosity of the solution. Elastomers used for this purpose include styrene-butadiene-styrene triblock rubber and styrene-isoprene-styrene triblock rubber.

A wide range of elastomers include polybutadiene, polyisoprene, butyl rubber, 1-ethylene brobylene-dienter polymer, and nitrile rubber.

The polymer molded product used in the present invention is produced by simultaneously performing polymerization and molding, as described above.

As mentioned above, such molding methods include the resin injection method, in which a premix in which the catalyst and raw material monomer are mixed using a static mixer or the like is flowed into the mold, and the resin injection method, in which the catalyst system is divided into two parts, solution A and solution B. It is possible to adopt the RIM method in which the mixture is mixed by collision at the head and then poured directly into the mold. In particular, the RIM method is commonly used.

In either case, the injection pressure into the mold can be relatively low, making it possible to use inexpensive molds. Further, when the polymerization reaction inside the mold starts, the temperature inside the mold rapidly rises due to the reaction heat, and the polymerization reaction ends in a short time.

Unlike polyurethane-RIMs, demolding is easy and often does not require special molding agents.

The polymer molded product thus obtained is subjected to a plating process as described above.

In addition to the three-step process described above, it is recommended to perform a cleaning process first. In other words, if the surface to be plated is contaminated with oil or fat, it is necessary to thoroughly clean it to remove it because subsequent steps are difficult. General plastic molded products often have a mold release agent attached to their surface for release from the mold, which is a problem, but the polymer of the present invention generally has a surface Since it requires little energy and has good mold releasability, and can be molded without using a special mold release agent as mentioned above, there is generally little dirt on the surface, and cleaning well with a neutral detergent is sufficient.

Furthermore, as described above, the pretreatment method of the present invention can be carried out in the simplest manner by simply leaving it in the air at room temperature for a certain period of time after molding. After that, there is no harm in doing it. just,
If the surface is dirty, the catalyst with oxygen molecules will be hindered, so depending on the degree of dirt, this can be done before pretreatment.

The pretreatment of the metathesis polymer according to the present invention is accomplished by leaving the molded product in air at room temperature, as described above.

By contact with such air, that is, by contact with oxygen molecules, the metathesis polymer containing a large amount of unsaturated bonds and allylic tertiary hydrogen is oxidized, and polar groups are introduced, resulting in appropriate hydrophilicity. This is so that it can be fulfilled. The degree of hydrophilization can also be tracked by measuring the infrared absorption spectrum of the surface and determining the degree of increase in the characteristic absorption of carbonyl, which was not present in the polymer initially, but a simpler and more direct method is to measure the infrared absorption spectrum of the surface. There is a method for estimating the surface energy by preparing a surface energy liquid and wetting the surface with it. According to this method, in the case of a metathesis polymer obtained using dicyclopentadiene as a monomer, the wetting energy of the surface immediately after molding is 34 d.
It is about yne/■, but if you leave it at room temperature for about 8 hours,
Although it increases to 38 dyne/(2), it has been found that when it exceeds that level, the adhesion of plating becomes better as described below.

That is, the pretreatment is achieved by increasing the wettability of the surface of the metathesis polymer molded product to 38 dyne/Cl11 or more using a catalyst with oxygen molecules.

As mentioned above, such a value can generally be achieved by leaving the product in air at room temperature for 8 hours or more, but as is well known, such an oxidation reaction can be accelerated by raising the temperature. Furthermore, the oxidation of the surface can be similarly accelerated by means such as irradiation with oxygen in the presence of air or the like or corona discharge.

As the material containing oxygen molecules, it is most economical and preferable to use air, but if necessary, oxygen-containing air with a higher oxygen concentration can also be used.

It is easy to understand that the advantage of this process is that it can be carried out extremely easily compared to pre-treatments used for general electroless plating of plastics, such as treatment with romic acid, sulfuric acid, or other solvents, which are difficult to handle. .

As mentioned above, the molded product that has been washed and pretreated as necessary is then subjected to (2J catalyst application and activation treatment).

In this catalyst application/activation treatment, the surface of the molded product is first treated with an acidic solution containing reducing ions, such as stannous chloride monohydrochloride or titanium dioxide-hydrochloric acid, and then palladium chloride-hydrochloric acid is applied. Another method is to form reduced colloidal particles of palladium or gold-platinum on the surface by treating with a similar salt-acidic solution of gold or platinum.

Furthermore, a method was devised in which stannous chloride and palladium chloride were mixed in hydrochloric acid to form a palladium colloid in the solution, and a method using a stabilized solution was devised, and this method is now more commonly used. There is. In this case, in order to activate the surface of the palladium colloid, a subsequent acid treatment is necessary to dissolve the stabilized ions.

With the colloidal nuclei thus attached to the surface of the molded product, a step of bringing the molded product into contact with an electroless plating solution to form an electroless plating layer is applied. As such electroless plating solutions, nickel-based ones and copper-based ones are often used, and nickel-based ones are particularly often used. In principle, such electroless plating solutions each contain an appropriate amount of P.
It basically consists of the relevant metal ion and a reducing agent capable of reducing it to the metal under H conditions, and in the case of nickel, a hypophosphite salt or borane is used as the reducing agent. Generally, the ionic liquid and the reducing agent liquid are prepared separately and mixed immediately before use. The lifespan after mixing depends on its composition and usage conditions.

In this electroless plating process, the appropriate temperature and treatment time differ depending on the liquid composition.Initially, high temperatures around 90°C were often used, but with improvements, the temperature is generally 25 to 40°C.
Increasingly, it is carried out at relatively low temperatures of C.

The uniformity of the adhesion of the plating layer by such electroless plating,
The strength of the adhesion is greatly affected by the quality of the pretreatment process as described above, and the treatment method of the present invention generally performs hydrophilization under mild conditions, unlike the deep etching of the surface. Therefore, the surface is smooth and activation can be performed uniformly, so that an electroless plating layer with a tingling and gloss can be deposited very uniformly.

After such electroless plating, a molded product with a metal surface can be obtained by plating copper, nilagel, chromium, etc. on the head using a conventional method, and can be used in a wide range of applications such as various transportation equipment, electrical equipment, housings, and building materials. It can be used for various purposes.

By the method of the present invention, a plated product with good surface properties can be obtained using an electroless plating layer with smooth and good surface properties.

The present invention will be explained in detail with reference to Examples below. Note that the examples are for illustrative purposes only and are not limited thereto.

Examples 1-2. Comparative Example: Preparation of molded plate for halogenation treatment> [Preparation of catalyst component solution] 20 parts by weight of tungsten hexachloride was added to 70 parts by volume of dry toluene under a nitrogen stream, and then nonylphenol 2
A 0.5 M tungsten-containing catalyst solution was prepared by adding a solution of 1 part by weight and 16 parts by volume of toluene, and the solution was purged with nitrogen gas overnight to react with tungsten hexachloride and nonylphenol. The generated hydrogen chloride gas was removed, and 1 part by volume of acetylacetone was added to 10 parts by volume of the solution to prepare a polymerization catalyst solution.

For a monomer mixture consisting of 95 parts by weight of purified dicyclopentadiene and 5 parts by weight of purified ethylidene norbornene,
The above polymerization catalyst solution was added to a solution containing 3 parts by weight of ethylene-propylene-ethylidene norbornene copolymer rubber with an ethylene content of 70 mol% and 22 parts by weight of Ethanoxfu 0 as an oxidation stabilizer. OOi M
A catalyst component solution (solution A) was prepared.

[Preparation of active inhibitor component solution] Trioctyl aluminum 85. Dioctyl aluminum iodide 15. A mixed solution of an activator for polymerization prepared by mixing in a molar ratio of 100 parts of diglyme was prepared using 95 parts by weight of purified dicyclopentadiene, 5 parts by weight of purified ethylidene norbornene, and 3 parts by weight of the same ethylene-propylene-ethylidene norbornene copolymer rubber as above. The active agent component solution (solution B) was prepared by mixing the mixture with aluminum at a ratio of 0.003 M.

Using Solution A and Solution B prepared as described above, a molded plate made of metasedis polymer having a thickness of 3 ms+ was produced using a reaction injection molding machine. The injection was carried out at a liquid temperature of 30°C and a mold temperature of 80°C.

The thus obtained flat plate was molded for 1 hour immediately after molding.

It was left open at room temperature for 2 hours, 4 o'clock, 8 hours, 24 hours, and 48 hours. During that time, the surface was degreased by washing for 5 minutes at 50 to 60°C in an aqueous solution of 50 t/l of Aclean detergent manufactured by Khitan Pharmaceutical Flavors, followed by washing with water.

After the above-mentioned time has elapsed, the surface wetting was measured by looking at the wetting of liquids with various surface energies prepared in advance, and the results were 34.34.35.36.38.38.38dyne/
After a predetermined period of time, each plate showing the value of c- is
Catalyst A-3080 [+11 manufactured by Khitan Pharmaceutical Co., Ltd. and concentrated hydrochloric acid 150+nl diluted to 11 with water were immersed in a catalyst-imparting solution for 2 minutes at 25°C, followed by water washing. It was immersed in a solution diluted to 11 with water at 35°C for 2 minutes, and then washed with water.

After that, TMP chemical nickel A160 mountain 1 manufactured by Khitan Pharmaceutical,
160 ml of B was immersed in an electroless plating solution diluted to 11 with water for 7 minutes at 35°C. After washing with water, it was dried with a dryer to obtain an electroless plated plate. Observing the plating adhesion status, it was immediately after molding and cleaning (34 dyne/cs)
After 1 hour without plating at all (34dyne/C11
) There is some plating, but it peels off easily when rubbed with a fingernail, and the adhesion is poor after 2 hours (35dyne/
am) After 4 hours (36 dyne/(m)) There was a considerable amount of plating, and some unplated areas remained, but the fixation of the plated areas was good and did not peel off easily.

After 8 hours to 48 hours (38 dyne/CI+) The entire surface was covered with shiny plating and the adhesion was very good.

For comparison, we tried pretreatment with chromic acid.

It was treated at 65° C. in a treatment solution prepared by diluting chromic anhydride (400 g) and concentrated sulfuric acid (380 g) to 11 (11:1) with water. If you use a plate that has been molded for more than 4 hours, the surface will turn white after 2 minutes or more of processing time, and the surface will become gray and cloudy with no nickel attached due to the subsequent electroless plating process. All I got was nothing.

On the other hand, when we similarly treat objects with chromic acid within 1 hour after molding, after 2 minutes to 4 hours of treatment, the electroless plated surface becomes only black, and after 5 to 8 minutes of treatment, it turns gray. A shiny plating surface cannot be obtained by the chromic acid treatment, and if the molded product is not left in the air for a long time, the plating may not adhere even if the chromic acid treatment is applied for a short period of time. It was found that the amount of oxygen was also not effective, indicating that treatment by sharing oxygen with oxygen has an extremely important effect as a pretreatment.

In addition, it was found that the chromic acid treatment commonly used for general plastics does not produce a shiny plating surface in the case of metathesis polymer moldings. 4th Amendment (Written) Patent Application No. 1-91766 No. 2, Invention Pretreatment method for electroless plating of polymer molded articles (1) "Tungsteoxychloride" in lines 1 and 2 on page 10 of the specification is corrected to "tungsten oxychloride."

that's all

Claims (1)

[Scope of Claims] Electroless plating on the surface of a metathesis polymer molded product obtained by molding a metathesis polymerizable monomer simultaneously with polymerization in the presence of a metathesis polymerizable catalyst system, (1) Pretreatment (2) Catalyst Application and Activation Treatment (3) Electroless plating characterized by using a method of making the molded product hydrophilic by bringing it into contact with oxygen molecules as a pretreatment method before applying the electroless plating process. Pretreatment method for plating.