JPS6329899B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for plating that can be directly electroplated without chemically plating a molded article. Conventionally, the method used was to knead carbon black into a rubber-based base and then add sulfur, etc., to increase conductivity and adhesion to the plating metal, and then apply direct electroplating. When these materials were molded and electroplated directly, it took time for strike plating, and even after a considerable amount of time, some areas remained that were not completely covered. This is due to the fact that the strike plating bath and the molded product originally have hydrophilic and hydrophobic surfaces, respectively.Currently, in order to avoid this, the strike plating bath has a surface of about 1 to 10 CC/C. A large amount of surfactant was added to the plating bath and stirred to improve the wettability of the plating resin and increase the speed of strike Ni plating. However, this method still causes many problems, as described below. (1) When air agitation is used to homogenize the liquid in the strike plating liquid, a large amount of air bubbles are generated at the same time as the air agitation, and the volatile content of these bubbles is violently released into the atmosphere, which may cause the surrounding environment to be affected during work. The negative effects, including harm to the human body, were a problem. (2) In addition, the plating bath liquid, not just the strike plating bath, is purified by continuous filtration with activated carbon during operation, but almost all of the surfactant in the liquid is adsorbed by the activated carbon. ,
Replenishment must be done at certain time intervals. (3) Addition of a large amount of surfactant also reduces the adhesion of plating. For these reasons, the addition of surfactants to the strike plating bath has been unfavorable. On the other hand, unless the wettability is improved, it is impossible to put this type of resin for plating into practical use, so various modifications of the resin have been investigated. One method is to modify the surface by etching with chromium mixed acid. However, this method uses an etching process that causes waste water pollution, and is not as effective as direct electroplating materials. The present inventors have conducted various studies on all types of surfactants available for improving wettability and their synergistic effects with other compounding agents, and have found that they are necessary not only for wettability but also for plating resins. We have now obtained a resin composition for plating that has excellent properties and can greatly improve the strike bath. The specific advantages of the plating resin composition of the present invention are as follows. (1) No surfactant added to the strike plating bath
It can be suppressed to ~1CC/approximately. (2) Therefore, the surfactant does not diffuse into the atmosphere. (3) The amount of surfactant adsorbed by the activated carbon during the process is almost eliminated, so there is less need for replenishment. In addition, as for the actual effect, (4) Since it is kneaded into the resin, the coverage of the plating has increased several times compared to before. (5) The amount of hydrogen adsorbed on the cathode during plating is reduced, and the appearance of the plating is improved. (6) Adhesion strength increases by several percent. The thermoplastic resin in the present invention includes polyethylene, polypropylene, ethylene propylene copolymer (EPR), ethylene propylene diene terpolymer (EPDM), ethylene vinyl acetate copolymer,
Polyvinyl chloride, polystyrene, polyamide such as polyacetal 6, 6-6, 6-10, 6-12, 11, 12, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polybutylene terephthalate (PBT) ), polyethylene terephthalate (PET), ABS, AS, polymethylpentene, styrene-butadiene-styrene copolymer (SBS), polycarbonate, etc. EPDM or EPR can be used regardless of Mooney viscosity, iodine value, or _C3 component. Includes rubber from Mitsui Petrochemicals, Nippon Synthetic Rubber, and Sumitomo Chemical. Sulfur-based vulcanizing agents and sulfur-releasing compounds are those commonly used in the rubber industry. Typical examples include those described on pages 2 to 5 of "Handbook of Rubber and Plastic Compounded Chemicals" (edited by Rubber Digest, published in 1972). Zinc oxides include those commonly used in the rubber industry. A typical example is "Handbook of Rubber and Plastic Compounded Chemicals" (edited by Rubber Digest Co., Ltd., published in 1971), pages 58 to 58.
Some are listed on page 60. Examples of vulcanization accelerators include thiazole type, imidazoline type, dithiocarbamate type, thiourea type, thiuram type, sulfenamide type, xanthate type,
It is classified into guanidine type and aldehyde-amine type, but typical examples are from pages 19 to 57 of the above publication.
There are some listed on the page. Carbon blacks include carbon blacks having various properties manufactured based on channel type, furnace type, acetylene type, and thermal type. Representative examples of these are described on pages 213 to 221 of the said publication. It is also described in detail in the ``Carbon Black Handbook'' (edited by the Carbon Black Association, published by Tosho Publishing in 1972). In this case, since the surfactant is connected to the cathode in the plating solution, it is desirable to have a charge state that allows metal ions to be reduced, and a nonionic or anionic surfactant is suitable. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, sorbitan fatty acid ester, polyoxymethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, and polyoxyethylene fatty acid. These include esters, glycerin fatty acid esters, oxyethylene/oxypropylene, block polymers, special nonionic surfactants, etc. Examples of anionic surfactants include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, dialkyl sulfosuccinic acid ester salts,
These include alkyl phosphate ester salts, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl sulfate ester salts, and the like. Among these, the nonionic surfactants polyoxyethylene alkyl ether, sorbitan fatty acid ester, polyoxymethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxybutylene sorbitan fatty acid ester, polyoxyethylene alkyl amine, and Oxyethylene fatty acid ester and glycerin fatty acid ester had particularly remarkable effects. The surfactant may be added by directly kneading it with other formulations, but the same effect can be obtained by adding it by masterbatch method. In addition to the composition, if necessary, the present invention also includes a stabilizer,
Lubricant, paraffin-based hardness adjustment oil, Mg
(OH) ₂ , Al(OH) ₃ , other fillers such as talcum glass fiber, Sb ₂ O ₃ , ZnBO ₃ , chlorinated paraffin,
Additives for other purposes such as flame retardants such as hexabromobenzene and decabromodiphenyl oxide may also be blended. The carbon black blended in the present invention imparts conductivity to the thermoplastic resin and rubber, and the conductivity improves as the amount increases, but if it exceeds 130 parts by weight based on the total weight of the thermoplastic resin and rubber. ,
Fluidity deteriorates rapidly, making not only molding difficult, but also impact resistance and plating appearance deteriorating. Also 15
If the amount is less than 1 part by weight, the electrical conductivity will not be improved and electroplating will not be possible even if a superconducting type carbon black of the above-mentioned carbon black is used. Regarding the addition of rubber, ethylene propylene rubber (EPR) or ethylene propylene diene rubber (EPDM) can be used regardless of whether it is saturated or unsaturated, but if it is added in excess of 100 parts by weight per 100 parts by weight of thermoplastic resin During kneading of the compound, and further during molding, the fluidity deteriorates, not only making molding difficult, but also deteriorating the appearance of the plating. Rubber is used to improve impact resistance, but as long as the weight part of carbon black added is low, it can be used without any problem in terms of impact resistance, so it may be 0 weight part. Next, the addition of sulfur is essential for improving the adhesion strength of plating, and in order to maintain this adhesion strength of 1 kg/cm or more, it is preferably 0.05 part by weight or more. However, if it exceeds 10 parts by weight, the odor becomes strong during the manufacturing process or molding of the molding material.
This is not desirable during the work, and furthermore, if the molded product is stored before the plating process, sulfur will bloom on the surface of the molded product, and even if it is subsequently plated, the appearance will be extremely poor. Zinc oxide is an inorganic vulcanization accelerator that is used in combination with sulfur, but by adding 0 to 10 parts by weight based on the total weight of the resin and rubber, the stability of adhesion caused by sulfur can be improved. can be promoted. The effects of zinc oxide have not yet been clarified, and it has been found that addition of zinc oxide improves kneading properties and formability, that is, plating appearance. However, if it exceeds 10 parts by weight, the flow properties and conductivity of the material will deteriorate. The vulcanization accelerator is used in combination with sulfur as an organic vulcanization accelerator, but when added at least 0.05 parts by weight based on the total weight of the resin and rubber, it stabilizes and improves adhesion, similar to zinc oxide. It was found that it promotes However, if it exceeds 10 parts by weight,
It was found to be undesirable because it causes odor during operation and blooming of molded products similar to sulfur. Lastly, there is the effect of adding a surfactant, which has the most significant effect on plating work and plating condition in the present invention. As explained above, this effect shows remarkable characteristics starting from 0.05 parts by weight based on the total weight of resin and rubber.
If the amount exceeds 1 part by weight, the kneading processability deteriorates and slippage occurs during the addition time of the resin, etc., often making kneading impossible. It was also found that the blooming of the surfactant from the surface of the molded article increased significantly, and the adhesion began to decrease. This will be explained in detail in Examples below. Example 1 Polypropylene (manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Noblen FC-240) and EPDM were used as thermoplastic resins.
EPT4021 manufactured by Mitsui Petrochemical Industries, Ltd. The sulfur-based vulcanizing agent is VALQUA (manufactured by Toyo Kagaku), the zinc oxide is zinc oxide manufactured by Sakai Chemical Industry Co., Ltd., and the vulcanization accelerator is Noxela manufactured by Ouchi Shinko Chemical Industry Co., Ltd. DM (MBTS), carbon black is Vulcan XC-72 manufactured by Kiabot Corporation in the United States, and surfactant is Nitsusan Nonion ST-221 manufactured by NOF Corporation.
was blended. These compositions were stirred and mixed in a blender for 5 minutes, and kneaded and extruded in a twin-screw continuous extruder (65 mm) to obtain compound pellets. This pellet is heated to 120℃.
Dry for 3 hours and use an 8oz injection molding machine under the optimum molding conditions for each composition to form a mold with a thickness of 3mm, a diameter of 100mm, and a surface area of approx.
A 1.6 dm ² disc was molded and its characteristics were evaluated by conducting various tests and directly electroplating it under the following plating conditions. Plating conditions (strike nickel: Watt bath) Liquid composition Nickel chloride 250g/Nickel sulfate 50g/Boric acid 40g/Liquid temperature 55℃ Operating conditions For striking speed 2V x 1 minute For appearance 1V-1 minute 2V-3 minutes 3A/dm After ^2-4 minutes, put it in a copper sulfate bath or various plating baths. Characteristics include kneading properties, fluidity (MI), impact resistance, moldability, odor, number of days for blooming, plating speed (dm ² /min), peeling test as plating adhesion strength, and plating appearance. The number of pits (pieces/cm ² ) was measured, and the results shown in Table 1 were obtained. As for the overall evaluation, 〇 marks are those that satisfy the present invention, and × marks are those that do not satisfy the present invention, and all the products of the present invention achieved their objectives.

【table】

[Table] Example 2 Nylon 6- manufactured by Ube Industries, Ltd. as a thermoplastic resin
1013B, Polyacetal-Dyuracon M90 manufactured by Polyplastics, Polypropylene manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Noblen-FL-630, Lion Akzo Ketchen Black as carbon black
EG, sulfur was powdered sulfur (200 mesh), vulcanization accelerator was Ouchi Shinko Kagaku Kogyo Noxeler M, ZnO was Zinc white from Sakai Chemical Industries, and surfactant was Kao Soap Co., Ltd. Electrostripper TS-2. The ingredients were mixed as shown in Table 2, and the same study as in Example 1 was conducted to obtain the results shown in Table 2. As a comprehensive evaluation, ○ marks are those that satisfy the present invention, × marks are those that do not satisfy the present invention, and all the products of the present invention achieved their objectives.

【table】

[Table] Example 3 100 parts by weight of polypropylene (manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Noblen FC-240) as a thermoplastic resin,
EPR was 004550 parts by weight manufactured by Mitsui Petrochemical Industries, Ltd.; sulfur-based vulcanizing agent, zinc oxide, vulcanization accelerator, and carbon black were the same as in Example 1; 5, 5, 1, and 50 parts by weight, respectively. Pellets were prepared in the same manner as in Example 1 to obtain a resin composition (A). Next, a surfactant (Nippon Oil Co., Ltd., Nitsusan Nonion ST-
221) with the above PP60 weight part and carbon black.
A masterbatch (B) was obtained by kneading 10 parts by weight of 30 parts by weight into pellets in the same manner. These were mixed as shown in Table 3 and examined in the same manner as in Example 1.
The table results were obtained. As a comprehensive evaluation, the mark ◯ indicates that the present invention is satisfied, and the mark x indicates that the present invention is not satisfied, and the present invention has achieved all of its objectives.

【table】

【table】

Claims (1)

[Scope of Claims] 1 (i) 100 parts by weight of thermoplastic resin, (ii) 0 to 100 parts by weight of ethylene propylene copolymer or ethylene propylene diene terpolymer, (iii) sulfur-based vulcanizing agent and sulfur at least one sulfur-based vulcanizing agent selected from the group of release compounds 0.05
~10 parts by weight, (iv) 0-10 parts by weight of zinc oxide, (v) 0.05-10 parts by weight of vulcanization accelerator, (vi) 15-130 parts by weight of carbon black, (vii) 0.05-5 parts by weight of surfactant. A resin composition for plating that contains the following: