Plated molded article, method for producing plated molded article, and case component

Abstract

The present invention addresses the problem of providing: a plated molded article wherein a plating layer having excellent surface smoothness is formed without sacrificing various excellent characteristics that are intrinsic to a polyphenylene sulfide resin, and the plating layer exhibits excellent adhesion, while ensuring high plating quality in a severe environmental degradation test such as a thermal shock cycle test; and a method for producing this plated molded article. In order to solve the problem, the main object of the present invention is a plated molded article which is obtained by forming a plating layer on a part or the entirety of the surface of a molded article that is formed of a polyphenylene sulfide resin composition that contains 30 to 200 parts by weight of (B) a fibrous filler relative to 100 parts by weight of (A) a polyphenylene sulfide resin, wherein the arithmetic mean roughness of the plating layer surface of the plated molded article is 1.5 μm or less.

Description

Plated molded products, manufacturing method for plated molded products, and housing parts

[0001] The present invention provides a plated molded article that has excellent surface smoothness and adhesion without sacrificing the various excellent properties inherent to polyphenylene sulfide resin, and that can ensure high plating quality even in severe environmental degradation tests such as thermal shock cycle tests.

[0002] Thermoplastic resin materials such as polyphenylene sulfide resin (hereinafter sometimes abbreviated as "PPS resin") are used in a wide range of industrial fields, primarily in the electrical and electronics and automotive fields, due to their excellent chemical resistance, heat resistance, flame retardancy, electrical properties, and mechanical properties. However, for example, PPS resin has such excellent chemical resistance that the resin surface of molded products is difficult to etch, making it generally unsuitable for plating.

[0003] In recent years, sensors, electronic control units, and other devices have come into widespread use in a wide range of fields, and there is a strong demand for them to have electromagnetic shielding properties to prevent mutual interference and thermal conductivity for heat management.

[0004] To meet these demands, plating resin molded products can be used to impart these properties, and this has been put to practical use. However, the PPS resin described above has good chemical resistance, making plating difficult. In addition, plating PPS resin requires surface roughening by blasting or strong acid treatment, resulting in high surface roughness in the resulting plated molded products, which can cause radio wave loss and loss of radio wave directionality, limiting their use. Therefore, there has been a demand for improved plating processability (platability) of PPS resin and improved surface smoothness in the resulting plated molded products.

[0005] In Patent Document 1, in order to improve plating properties, the calorific value of cold crystallization is increased to 5.0 g / J or more to produce a molded product with low surface crystallinity, and further, a specific primer paint containing active metal particles is used to obtain a plated molded product with high adhesion.

[0006] Patent Document 2 discloses a resin composition containing potassium titanate for the purpose of improving plating properties.

[0007] Non-Patent Document 1 describes that plating adhesion can be improved by subjecting PPS resin to UV irradiation and alkaline etching treatment.

[0008] JP 2003-96221 A JP 62-270659 A

[0009] Surface Technology, 2017, Vol. 68, No. 11, pp. 624-629

[0010] However, Patent Document 1 states that molded articles with low crystallinity have poor surface appearance, significantly deteriorating decorativeness after plating. Furthermore, when used in a high-temperature environment, changes in crystallinity occur, resulting in changes in dimensional characteristics and other factors, resulting in unsatisfactory properties for the plated molded articles. Patent Document 2 states that the inclusion of metallic foreign matter such as potassium titanate significantly impairs the mechanical strength of the molded article. Non-Patent Document 1 shows the effect on unreinforced PPS resin, but reinforced PPS resins containing inorganic substances such as fibrous fillers have the drawback of not improving plating adhesion because surface roughness is suppressed.

[0011] The present invention provides a plated molded article and a method for producing the same that enable the formation of a plating layer with excellent surface smoothness without sacrificing the various excellent properties inherent to PPS resin, that has excellent plating layer adhesion, and that ensures high plating quality even in severe environmental degradation tests such as thermal shock cycle tests.

[0012] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. That is, the present invention provides the following.

[0013] (1) A plated molded article comprising a plated layer on a part or all of a molded article formed from a polyphenylene sulfide resin composition containing 30 to 200 parts by weight of (B) a fibrous filler per 100 parts by weight of (A) polyphenylene sulfide resin, wherein the arithmetic mean roughness of the plated layer surface in the plated molded article is 1.5 μm or less. (2) The plated molded article according to (1), wherein the (A) polyphenylene sulfide resin contains 20% by weight or more of (A-1) a polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315° C. and a load of 2,160 g, when the total amount of the (A) polyphenylene sulfide resin is taken as 100% by weight. (3) The plated molded article according to (1) or (2), characterized in that the polyphenylene sulfide resin composition further contains, per 100 parts by weight of (A) polyphenylene sulfide resin, 1 to 30 parts by weight of (C) a functional group-containing olefin copolymer containing at least one functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salt, and an alkoxycarbonyl group. (4) The plated molded article according to any one of (1) to (3), characterized in that the (A) polyphenylene sulfide resin contains, when the total amount of the (A) polyphenylene sulfide resin is taken as 100% by weight, 50% by weight or more of (A-1) a polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315°C and a load of 2160 g. (5) The plated molded article according to (3) or (4), wherein the functional group contained in the functional group-containing olefin copolymer (C) containing at least one functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salt, and an alkoxycarbonyl group is a glycidyl group, and the glycidyl group concentration in the functional group-containing olefin copolymer is 1.0 to 4.5 wt %. (6) A method for producing a plated molded article according to any of (1) to (5), wherein a molded article formed from the polyphenylene sulfide resin composition is subjected to a surface treatment step, a catalyst application step, an activation treatment step, and a plating treatment step in this order. (7) The method for producing a plated molded article according to (6), wherein the surface treatment step is carried out as follows.(a) irradiating the surface of the molded article with ultraviolet light having a dominant wavelength of 100 to 400 nm for 10 to 120 minutes from a position 5 to 200 mm away from the surface of the molded article. (b) Thereafter, immersing the molded article treated in (a) in an alkaline aqueous solution having a concentration of 5 to 40 mass % for 1 to 30 minutes. (8) A method for producing a plated molded article according to (6) or (7), in which at least a portion of the surface of the molded article after the surface treatment step has pores with a diameter of 2 μm or less. (9) A housing part having the plated molded article according to any one of (1) to (5) as part of its constituent parts.

[0014] The present invention provides a plated molded article and a method for producing the same that enable the formation of a plating layer with excellent surface smoothness without sacrificing the various excellent properties inherent to polyphenylene sulfide resin, that has excellent adhesion to the plating layer, and that ensures high plating quality even in severe environmental degradation tests such as thermal shock cycle tests.

[0015] 1A and 1B are test pieces for measuring peel strength, in which (a) is a plan view and (b) is a side view.

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, "weight" means "mass."

[0017] The polyphenylene sulfide resin (A) used in the present invention is a polymer having a repeating unit represented by the following structural formula:

[0018]

[0019] From the viewpoint of heat resistance, the polyphenylene sulfide resin (A) used in the present invention is preferably a polymer containing 70 mol % or more, and more preferably 90 mol % or more, of repeating units represented by the above structural formula. Furthermore, the polyphenylene sulfide resin (A) used in the present invention may be composed of repeating units having the following structure in an amount of less than 30 mol %:

[0020]

[0021] Next, a method for obtaining the polyphenylene sulfide resin (A) used in the present invention will be described. The PPS resin can be produced by known methods, including a pre-process, a polymerization reaction process, a recovery process, and a post-treatment process. The raw materials and pre-process used in the production of the PPS resin preferably conform to the method described in JP 2017-155221 A. The PPS resin of the present invention preferably contains (A-1) a polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315°C and a load of 2160 g (hereinafter, sometimes abbreviated as "(A-1) high-viscosity PPS resin"). A method for obtaining a PPS resin with such characteristics includes production via the key steps described below. For example, a high-viscosity polyphenylene sulfide resin having the above characteristics can be obtained by using a quenching method in the recovery process described below or by crosslinking by heat treatment in the presence of oxygen.

[0022] The polymerization reaction step, recovery step, and post-treatment step will be described below.

[0023] [Polymerization Reaction Step] The PPS resin is preferably produced by reacting a sulfidizing agent with a polyhalogenated aromatic compound in an organic polar solvent at a temperature ranging from 200 to 290°C.

[0024] To start the polymerization reaction, the sulfidizing agent and the polyhalogenated aromatic compound are added to an organic polar solvent, preferably in an inert gas atmosphere, at a temperature ranging from room temperature to 220°C, and more preferably from 100 to 220°C. A polymerization aid may also be added at this stage. There is no particular limitation on the order in which these raw materials are added, and they may be added simultaneously.

[0025] The mixture is usually heated to a temperature in the range of 200° C. to 290° C. There are no particular restrictions on the rate of temperature increase, but a rate of 0.01 to 5° C. / min is usually selected, and a range of 0.1 to 3° C. / min is more preferred.

[0026] In general, the temperature is finally raised to 250 to 290° C., and the reaction is carried out at that temperature for usually 0.25 to 50 hours, preferably 0.5 to 20 hours.

[0027] Before reaching the final temperature, for example, a method of reacting at 200° C. to 260° C. for a certain period of time and then raising the temperature to 270 to 290° C. is effective in obtaining a higher degree of polymerization. In this case, the reaction time at 200° C. to 260° C. is usually selected from the range of 0.25 to 20 hours, preferably 0.25 to 10 hours.

[0028] In order to obtain a polymer with a higher degree of polymerization, it is effective to carry out the polymerization reaction in multiple stages. When carrying out the polymerization reaction in multiple stages, it is effective to move to the next stage when the conversion of the polyhalogenated aromatic compound in the system at 245°C reaches 40 mol% or more, preferably 60 mol%.

[0029] [Recovery Step] After the polymerization reaction step is completed, solid matter is recovered from the polymerization reaction product containing the polymer, solvent, and the like.

[0030] A preferred method for recovering PPS resin is to perform the recovery under rapid cooling conditions, and one preferred recovery method is the flash method. In the flash method, the polymerization reaction product is subjected to high temperature and high pressure (usually 250°C or higher, 8 kg / cm ２ In this method, the polymer is flashed from a pressure (or above) into an atmosphere of normal pressure or reduced pressure, and the polymer is recovered in powder form at the same time as the solvent is recovered. Flashing here means that the polymerization reaction product is ejected from a nozzle. Specific examples of the medium used for flashing include nitrogen or water vapor at normal pressure, and the temperature during flashing is usually selected from the range of 150°C to 250°C.

[0031] The flash method is an economical recovery method because it can recover solids simultaneously with the solvent and can recover the solids in a relatively short time. In this recovery method, ionic compounds such as sodium and organic low-molecular-weight polymers (oligomers) tend to be incorporated into the polymer during the solidification process.

[0032] However, the method for recovering the PPS resin used in the production method of the present invention is not limited to the flash method, and any method that satisfies the requirements of the present invention, in which a polymerization reaction product containing a polymer, a solvent, etc. is slowly cooled to recover a particulate polymer (quench method), may be used. However, from the viewpoint of economy, it is more preferable to use PPS resin recovered by the flash method.

[0033] [Post-Treatment Step (Acid Treatment)] In the present invention, it is preferable to subject the PPS resin obtained through the above-described polymerization reaction step and recovery step to an acid treatment.

[0034] The acid used in the acid treatment in the present invention is not particularly limited as long as it does not have the effect of decomposing the PPS resin, and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Of these, acetic acid and hydrochloric acid are more preferably used, but acids such as nitric acid that decompose and deteriorate the PPS resin are not preferred.

[0035] When an aqueous acid solution is used, the water is preferably distilled water or deionized water. The aqueous acid solution preferably has a pH of 1 to 7, more preferably a pH of 2 to 4. A pH of 7 or less is preferred because it prevents an increase in the amount of metal contained in the PPS resin. A pH of 1 or more is preferred because it also prevents the amount of volatile components contained in the PPS resin.

[0036] The acid treatment method preferably involves immersing the PPS resin in acid or an aqueous solution of acid, with appropriate stirring and heating possible as needed. The heating temperature is preferably 80 to 250°C, more preferably 120 to 200°C, and even more preferably 150 to 200°C. Temperatures below 80°C result in a small acid treatment effect and an increased metal content, while temperatures above 250°C result in excessively high pressure, which is undesirable from a safety perspective. Furthermore, when the PPS resin is immersed in an aqueous acid solution for treatment, the pH is preferably less than 8, more preferably 2 to 8. A pH of 8 or less is preferred because it prevents an increase in the amount of metal contained in the resulting PPS resin.

[0037] The acid treatment time is preferably a time sufficient for the reaction between the PPS resin and the acid to reach a sufficient equilibrium, and is preferably 2 to 24 hours when treated at 80°C, and 0.01 to 5 hours when treated at 200°C.

[0038] The ratio of the PPS resin to the acid or acid aqueous solution in the acid treatment is preferably such that the PPS resin is sufficiently immersed in the acid or acid aqueous solution, with 0.5 to 500 L of acid or acid aqueous solution being preferred, more preferably 1 to 100 L, and even more preferably 2.5 to 20 L per 500 g of PPS resin. Using 0.5 L or more of acid or acid aqueous solution per 500 g of PPS resin allows the PPS resin to be sufficiently immersed in the solution, preventing poor cleaning and preventing an increase in the amount of metal contained in the PPS resin, which is preferable. Furthermore, using 500 L or less of acid or acid aqueous solution per 500 g of PPS resin is also preferable because it prevents a significant decrease in production efficiency due to an excessive amount of acid or acid aqueous solution used relative to the PPS resin.

[0039] These acid treatments are carried out by adding a predetermined amount of PPS resin to a predetermined amount of water and acid, heating and stirring the mixture in a pressure vessel, or by continuous acid treatment. Separating the aqueous solution and PPS resin from the treatment solution after acid treatment can be easily achieved by filtration using a sieve or filter, including natural filtration, pressure filtration, vacuum filtration, and centrifugal filtration. To remove the acid and impurities remaining on the surface of the PPS resin separated from the treatment solution, it is preferable to wash the PPS resin several times with cold or warm water. Examples of washing methods include filtering the PPS resin while pouring water over it on a filter, or adding the separated PPS resin to pre-prepared water and then filtering it again to separate the aqueous solution from the PPS resin. The water used for washing is preferably distilled water or deionized water. It is believed that the terminal structure of the PPS resin treated with acid in this way changes. However, it is difficult to express the structure of the PPS resin obtained by acid treatment in a general formula, and it is also difficult to identify it based on its properties. Therefore, it can only be identified by the process (acid treatment) used to obtain the PPS resin.

[0040] [Post-treatment step (hot water treatment)] In the present invention, it is preferable to carry out hot water treatment before the acid treatment step, and the method is as follows. The water used in the hot water treatment in the present invention is preferably distilled water or deionized water. The hot water treatment temperature is preferably 80 to 250°C, more preferably 120 to 200°C, and even more preferably 150 to 200°C. By setting the temperature to 80°C or higher, the hot water treatment effect can be fully exerted and the amount of volatilized gas generated can be suppressed. By setting the temperature to 250°C or lower, an increase in pressure can also be suppressed, which is preferable from the standpoint of safety.

[0041] The hot water treatment time is preferably a time that allows sufficient extraction treatment of the PPS resin with hot water, and is preferably 2 to 24 hours when treated at 80°C, and preferably 0.01 to 5 hours when treated at 200°C.

[0042] The ratio of PPS resin to hot water in the hot water treatment is preferably such that the PPS resin is sufficiently immersed in the hot water, with 0.5 to 500 L of water per 500 g of PPS resin being preferred, more preferably 1 to 100 L, and even more preferably 2.5 to 20 L. Using 0.5 L or more of hot water per 500 g of PPS resin is preferred because the PPS resin is sufficiently immersed in the hot water, preventing poor cleaning and preventing an increase in the amount of volatile gas generated. Furthermore, using 500 L or less of hot water per 500 g of PPS resin is also preferred because it prevents a significant decrease in production efficiency due to a large excess of water relative to the PPS resin.

[0043] There are no particular limitations on the operation of these hot water treatments, and they can be carried out by, for example, adding a predetermined amount of PPS resin to a predetermined amount of water and heating and stirring in a pressure vessel, or by continuously performing hot water treatments. There are no particular limitations on the method for separating the aqueous solution and PPS resin from the treatment solution after hot water treatment, but filtration using a sieve or filter is convenient, and examples include natural filtration, pressure filtration, vacuum filtration, and centrifugal filtration. In order to remove impurities remaining on the surface of the PPS resin separated from the treatment solution, it is preferable to wash the PPS resin several times with water or hot water. There are no particular limitations on the washing method, but examples include a method of filtering the PPS resin while pouring water over it on a filter, or a method of separating the aqueous solution and the PPS resin by adding the separated PPS resin to previously prepared water and then filtering it again. The water used for washing is preferably distilled water or deionized water.

[0044] Since decomposition of the PPS end groups during the acid treatment or hot water treatment is undesirable, it is desirable to carry out the acid treatment or hot water treatment in an inert atmosphere, such as nitrogen, helium, or argon, with a nitrogen atmosphere being preferred from an economical standpoint.

[0045] [Post-Treatment Step (Washing with Organic Solvent)] In the present invention, a step of washing with an organic solvent may be included before the step of acid treatment or hot water treatment of the PPS resin, and the method is as follows: The organic solvent used in washing the PPS resin in the present invention is not particularly limited as long as it does not have the action of decomposing the PPS resin, and examples thereof include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphoramide, and piperazinones; sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, and the like; Examples of suitable organic solvents include ether-based solvents such as chlorofuran, halogen-based solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene, alcohol-phenol-based solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol, and aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene. Among these organic solvents, N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform are particularly preferred. These organic solvents may be used alone or in combination.

[0046] Methods for washing with an organic solvent include immersing the PPS resin in the organic solvent, and stirring or heating can be performed as necessary. There are no particular restrictions on the washing temperature when washing the PPS resin with an organic solvent, and any temperature between room temperature and approximately 300°C can be selected. While higher washing temperatures tend to increase the washing efficiency, a washing temperature between room temperature and 150°C is usually sufficient. Washing can also be performed under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There are also no particular restrictions on the washing time. While it depends on the washing conditions, in the case of batch-type washing, washing for 5 minutes or more usually produces a sufficient effect. Continuous washing is also possible.

[0047] The acid treatment, hot water treatment, and washing with an organic solvent may be carried out in appropriate combination.

[0048] [Heat Treatment Step] In the present invention, by further heat treating the PPS resin after the above post-treatment step, molecular chains are crosslinked to each other, thereby obtaining a PPS resin with high mechanical strength and excellent dimensional stability. By using such a heat treatment step, the above-mentioned (A-1) high-viscosity PPS resin can be easily obtained. The heat treatment step will be specifically described below.

[0049] In the present invention, heat treatment can be performed to obtain a PPS resin with high mechanical strength, but excessive heat treatment is not preferable because it reduces melt fluidity and increases gelled matter in the resin, causing incomplete filling during molding. However, if the heat treatment is too mild, the effect of reducing volatile components is small, the strength of the resin decreases, and antifreeze resistance also tends to decrease. The heat treatment of the present invention makes it possible to obtain a PPS resin with improved mechanical strength while suppressing the generation of gelled matter without impairing melt fluidity.

[0050] The heat treatment may be carried out in an atmosphere with a high or low oxygen concentration, provided that the heat treatment temperature and time are within specific ranges.

[0051] The conditions for a high oxygen concentration atmosphere are preferably an oxygen concentration exceeding 2% by volume, with a heat treatment temperature of 160 to 270°C and a heat treatment time of 0.1 to 17 hours. However, under conditions of high oxygen concentration, although the reduction rate of volatile components is rapid, oxidative crosslinking also progresses rapidly, making gelation more likely. Therefore, it is generally preferable to perform heat treatment at a low temperature for a long time or at a high temperature for a short time. Specific conditions for low-temperature, long-term heat treatment are preferably 160°C to 210°C and 1 hour to 17 hours, and more preferably 170°C to 200°C and 1 hour to 10 hours. Heat treatment at a temperature below 160°C is only effective in reducing volatile components and in improving mechanical strength. Furthermore, even at low temperatures, under conditions of an oxygen concentration exceeding 2% by volume, oxidative crosslinking progresses and gelation is more likely to occur if the heat treatment time exceeds 17 hours. Specific conditions for high-temperature, short-time heat treatment are preferably above 210°C and not more than 270°C for 0.1 to less than 1 hour, and more preferably from 220°C to 260°C for 0.2 to 0.8 hours. If the heat treatment temperature exceeds 270°C, oxidative crosslinking progresses rapidly and gelation is likely to occur. Furthermore, even if the heat treatment is performed at a high temperature, if the heat treatment time is less than 0.1 hour, the effect of reducing volatile components is small and the effect of improving mechanical strength is small.

[0052] The conditions for a low oxygen concentration atmosphere are preferably an oxygen concentration of 2% by volume or less, a heat treatment temperature of 210 to 270°C, and a heat treatment time of 0.2 to 50 hours. Since a low oxygen concentration tends to reduce the effect of reducing volatile components, it is generally preferable to perform the heat treatment at a high temperature for a long time, and more preferably at a heat treatment temperature of 220 to 260°C for 2 to 20 hours. If the heat treatment time is below 210°C, the amount of volatile components in the PPS resin will not be reduced and the effect of improving mechanical strength will be small, and if the heat treatment time exceeds 50 hours, productivity will decrease.

[0053] The heating device for the heat treatment applicable to the present invention may be a conventional hot air dryer or a rotary or impeller-equipped heating device. However, for efficient and more uniform treatment, a rotary or impeller-equipped heating device is more preferable. Examples include paddle dryers, fluidized-bed dryers, KID dryers, steam tube dryers, inclined disk dryers, hopper dryers, and vertical agitator dryers. Among these, paddle dryers, fluidized-bed dryers, and KID dryers are preferred for uniform and efficient heating. To adjust the oxygen concentration during heat treatment, non-oxidizing inert gases such as nitrogen, argon, helium, and water vapor may be mixed with oxidizing gases such as oxygen, air, and ozone. As long as the heat treatment can be performed within the heating device, there is no particular restriction on whether the oxidizing gas or inert gas can be introduced from the top, bottom, or side of the heating device. However, a more convenient method is to introduce the gas from the top of the heating device. The oxidizing gas and the inert gas may be mixed before being introduced into the heating device, or the oxidizing gas and the inert gas may be mixed separately from different positions in the heating device.

[0054] Although the structure of the PPS resin is thought to change through the heat treatment process, the PPS resin obtained through the heat treatment has a complex and diverse structure, and there are circumstances in which it is impractical to identify the structure of the PPS resin. By undergoing the heat treatment process, it is possible to remove volatile matter and moisture contained in the PPS resin, and it is possible to obtain a PPS resin that is excellent in mechanical strength and dimensional stability.

[0055] The melt flow rate (hereinafter sometimes abbreviated as "MFR") of the PPS resin obtained through the above-mentioned polymerization reaction step, recovery step, post-treatment step, and, if necessary, heat treatment step, is preferably 1000 g / 10 min or less.

[0056] The PPS resin used in the present invention preferably contains 20 wt % or more, and more preferably 50 wt % or more, of (A-1) PPS resin having an MFR of 50 to 600 g / 10 min, based on 100 wt % of (A) polyphenylene sulfide resin, from the viewpoint of improving plating properties. An MFR of 50 g / 10 min or more is preferred because it prevents deterioration of moldability. An MFR of 600 g / 10 min or less is preferred because it prevents the formation of a plating layer or deterioration of the adhesion of the plating layer. More preferably, the MFR is 100 to 500 g / 10 min. Here, the MFR is a value measured in accordance with ASTM-D1238-70 under conditions of 315°C and a load of 2160 g. Containing 50 wt % or more of (A-1) high-viscosity PPS resin per 100 parts by weight of (A) polyphenylene sulfide resin further improves plating properties, which is preferred. The upper limit of the content of the (A-1) high-viscosity PPS resin in the (A) polyphenylene sulfide resin is 100% by weight, that is, it is most preferable to use only the (A-1) high-viscosity PPS resin.

[0057] The polyphenylene sulfide resin composition used in the present invention contains (B) a fibrous filler. Specific examples of (B) the fibrous filler include glass fiber, milled glass fiber, flat glass fiber, modified cross-section glass fiber, cut glass fiber, stainless steel fiber, metal fiber such as aluminum fiber or brass fiber, organic fiber such as aromatic polyamide fiber or Kevlar fibril, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, etc.

[0058] Among (B) fibrous fillers, it is preferable to use at least one selected from glass fiber, glass milled fiber, glass flat fiber, and modified cross-section glass fiber in view of mechanical properties and dimensional properties. The glass fiber and other fillers used in the present invention may be used after their surfaces are treated with a known coupling agent (e.g., a silane-based coupling agent, a titanate-based coupling agent, etc.) or other surface treatments.

[0059] The content of (B) fibrous filler in the polyphenylene sulfide resin composition must be 30 to 200 parts by weight per 100 parts by weight of (A) polyphenylene sulfide resin to balance heat resistance and mechanical properties. It is more preferably 40 to 150 parts by weight, and even more preferably 50 to 110 parts by weight. If the content is less than 30 parts by weight, the linear expansion coefficient of the PPS resin is large, resulting in a large difference in linear expansion from the metal forming the plating layer. This increases the stress generated during heat cycling, which tends to deteriorate adhesion. If the content exceeds 200 parts by weight, excessive surface roughening occurs, preventing the expected anchoring effect during plating, which tends to deteriorate adhesion.

[0060] Next, the polyphenylene sulfide resin composition used in the present invention preferably contains (C) a functional group-containing olefin copolymer (hereinafter sometimes abbreviated as "(C) functional group-containing olefin copolymer") containing at least one functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salts, and an alkoxycarbonyl group. The (C) functional group-containing olefin copolymer can be obtained by introducing a monomer component (functional group-containing component) having a functional group such as a glycidyl group, an acid anhydride group, or an ionomer into an olefin polymer and / or an olefin copolymer. Examples of the functional group-containing component include monomers containing an acid anhydride group such as maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo[2.2.1]5-heptene-2,3-dicarboxylic acid, and endobicyclo-[2.2.1]5-heptene-2,3-dicarboxylic acid anhydride; monomers containing a glycidyl group such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate; and monomers containing an ionomer such as a carboxylic acid metal complex.

[0061] Examples of olefin copolymers include (co)polymers obtained by polymerizing α-olefins such as ethylene, propylene, butene-1, pentene-1, octene-1, 4-methylpentene-1, and isobutylene, either alone or in combination, and copolymers of α-olefins with α,β-unsaturated acids and alkyl esters thereof, such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Specific examples include ethylene / propylene copolymers ("A / B" indicates a copolymer of A and B, the same applies hereinafter), ethylene / butene-1 copolymers, ethylene / hexene-1 copolymers, ethylene / octene-1 copolymers, ethylene / methyl acrylate copolymers, ethylene / ethyl acrylate copolymers, ethylene / butyl acrylate copolymers, ethylene / methyl methacrylate copolymers, ethylene / ethyl methacrylate copolymers, and ethylene / butyl methacrylate copolymers. Among the functional groups, glycidyl groups are preferred for improved plating properties.

[0062] The method for introducing a functional group-containing component into these olefin copolymers is not particularly limited, and methods such as copolymerizing the functional group-containing component when (co)polymerizing the same olefin copolymer as used as the olefin copolymer, or introducing the functional group into an olefin copolymer by graft copolymerization using a radical initiator can be used. Particularly useful specific examples of olefin copolymers obtained by introducing a monomer component having a functional group such as a glycidyl group, an acid anhydride group, or an ionomer into an olefin polymer include ethylene / propylene-g-glycidyl methacrylate copolymer ("g" represents graft, the same applies hereinafter), ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, ethylene / propylene-g-glycidyl anhydride copolymer, Preferred examples of the functional group-containing component include ethylene / butene-1-g-maleic anhydride copolymer, ethylene / methyl acrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleic anhydride copolymer, ethylene / methyl methacrylate-g-maleic anhydride copolymer, ethylene / ethyl methacrylate-g-maleic anhydride copolymer, zinc complex of ethylene / methacrylic acid copolymer, magnesium complex of ethylene / methacrylic acid copolymer, sodium complex of ethylene / methacrylic acid copolymer, and glycidyl esters of α-olefins such as ethylene and propylene with α,β-unsaturated acids. The functional group-containing component is most preferably a glycidyl group, with a glycidyl group concentration in the range of 1.0 to 4.0 wt%, preferably 1.1 to 3.9 wt%. The glycidyl group concentration of the (C) functional group-containing olefin copolymer is calculated using the following formula (1): A concentration of 1.0 wt% or more provides good compatibility with PPS resins and improved mechanical properties. By adjusting the content to 4.0 wt % or less, the adhesion of the plating layer is improved. Glycidyl group concentration (wt %)=A×A Equation (1) Ｍ / Gly Ｍ A [wt %]: content of glycidyl group-containing component in functional group-containing olefin copolymer A Ｍ[g / mol]: Molecular weight of glycidyl group-containing component Gly Ｍ [g / mol]: molecular weight of the glycidyl group (43 g / mol).

[0063] The glycidyl group-containing component herein refers to a repeating unit containing a glycidyl group among the repeating units constituting the functional group-containing olefin copolymer (C).

[0064] The functional group-containing olefin copolymer (C) is preferably contained in an amount of 1 to 30 parts by weight per 100 parts by weight of the polyphenylene sulfide resin (A). An amount of 1 part by weight or more improves the adhesion of the plating layer, while an amount of 30 parts by weight or less is preferred because it suppresses adhesion to the mold during injection molding and prevents the appearance of the product from being affected by gas generated by decomposition.

[0065] Furthermore, the polyphenylene sulfide resin composition used in the present invention may contain (D) a non-fibrous inorganic filler, if necessary. Examples of (D) non-fibrous inorganic fillers include E-glass (plate-like, scaly, granular, irregular, crushed), H-glass (plate-like, scaly, granular, irregular, crushed), A-glass (plate-like, scaly, granular, irregular, crushed), C-glass (plate-like, scaly, granular, irregular, crushed), natural quartz glass (plate-like, scaly, granular, irregular, crushed), synthetic quartz glass (plate-like, scaly, granular, irregular, crushed), talc, kaolin, silica (crushed, spherical), quartz, calcium carbonate, zinc carbonate, mica, glass beads, glass flakes, crushed, irregular, crushed. Examples of suitable metal oxides include glass, glass microballoons, clay, molybdenum disulfide, aluminum oxide (crushed), translucent alumina (plate-like, flaky, granular, irregularly shaped, and crushed), titanium oxide (crushed), and zinc oxide (plate-like, flaky, granular, irregularly shaped, and crushed), metal hydroxides such as aluminum hydroxide (plate-like, flaky, granular, irregularly shaped, and crushed), aluminum nitride, translucent aluminum nitride (plate-like, flaky, granular, irregularly shaped, and crushed), calcium polyphosphate, metal powder, metal flakes, metal ribbon, and metal oxide. Specific examples of metal species for metal powder, metal flakes, and metal ribbon include silver, nickel, copper, zinc, aluminum, stainless steel, iron, brass, chromium, and tin. From the perspective of mechanical properties and dimensional characteristics, it is particularly preferable to include at least one metal selected from talc, kaolin, silica, calcium carbonate, glass beads, and glass flakes.

[0066] The content of the (D) non-fibrous inorganic filler is 0.5 to 60 parts by weight, preferably 0.5 to 35 parts by weight, and more preferably 0.5 to 25 parts by weight, per 100 parts by weight of the (A) polyphenylene sulfide resin, from the viewpoint of a balance between plating adhesion, heat resistance, and mechanical properties. By adding 0.5 parts by weight or more, the necessary surface roughness can be obtained during plating. By adding 60 parts by weight or less, the surface is not roughened more than necessary during chemical treatment in the plating process, and the adhesion of the plating layer can be maintained.

[0067] Furthermore, the ratio Y / X, where X is the blend weight of the non-fibrous inorganic filler (D) and Y is the blend weight of the fibrous filler (B) relative to 100 parts by weight of the polyphenylene sulfide resin (A), is at least 2, and preferably at least 3. When the ratio is 2 or more, the surface is not roughened more than necessary during chemical treatment in the plating step, and the adhesion of the plating layer can be maintained.

[0068] The PPS resin composition of the present invention may contain, within the scope of the present invention, (E) a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms that does not contain a functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salt, and an alkoxycarbonyl group (hereinafter, this may be abbreviated as "(E) an olefin copolymer that does not contain a functional group"). Examples of the α-olefin having 3 to 12 carbon atoms include propylene, butene-1, pentene-1, octene-1, 4-methylpentene-1, and isobutylene, and the α-olefin may be a (co)polymer obtained by polymerizing a single α-olefin or two or more types of α-olefins.

[0069] The content of the (E) olefin copolymer not containing a functional group is preferably 1 to 3 parts by weight, particularly preferably 0 to 1.5 parts by weight, per 100 parts by weight of the (A) polyphenylene sulfide resin. Addition of 1 part by weight or more is preferred because heat cycle resistance is dramatically improved. A content of 3 parts by weight or less is preferred because heat cycle resistance is improved while dimensional stability is maintained.

[0070] The polyphenylene sulfide resin composition used in the present invention may contain (F) an alkoxysilane compound having at least one functional group selected from an epoxy group, an amino group, an isocyanate group, a hydroxyl group, a mercapto group, and a ureido group (hereinafter, this may be referred to as "silane compound (F)"), within the range that does not impair the effects of the present invention.

[0071] The content of the (F) silane compound is preferably 0.1 to 3 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin, which allows for both excellent fluidity and weld strength.

[0072] Furthermore, the polyphenylene sulfide resin composition used in the present invention may be blended with other resins besides (A) the polyphenylene sulfide resin, (C) the functional group-containing olefin copolymer, and (E) the functional group-free olefin copolymer, as long as the effects of the present invention are not impaired. While there are no particular limitations on the resins that can be blended, specific examples include polyamide resins such as nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, and aromatic nylons; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexyldimethylene terephthalate, and polynaphthalene terephthalate; polyamideimide, polyacetal, polyimide, polyetherimide, polyethersulfone, modified polyphenylene ether resin, polysulfone resin, polyarylsulfone resin, polyketone resin, polyarylate resin, liquid crystal polymer, polyetherketone resin, polythioetherketone resin, polyetheretherketone resin, and tetrafluoroethylene resin.

[0073] The polyphenylene sulfide resin composition used in the present invention may contain other components, such as antioxidants and heat stabilizers (hindered phenols, hydroquinones, phosphorus, phosphites, amines, sulfur-based compounds, and substituted versions thereof), weathering agents (resorcinols, salicylates, benzotriazoles, benzophenones, hindered amines, and the like), release agents and lubricants (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide, stearate, bisurea, polyethylene wax, and the like), pigments (cadmium sulfide, phthalocyanine, coloring carbon black, and the like), dyes (nigrosine, and the like), nucleating agents (inorganic or organic nucleating agents such as talc, silica, kaolin, and clay), and plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, and the like). Common additives that can be added include antistatic agents (anionic alkyl sulfate antistatic agents, cationic quaternary ammonium salt antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, and betaine amphoteric antistatic agents), flame retardants (e.g., red phosphorus, phosphate esters, melamine cyanurate, hydroxides such as magnesium hydroxide and aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resins, and combinations of these brominated flame retardants with antimony trioxide), heat stabilizers, lubricants such as calcium stearate, aluminum stearate, and lithium stearate, strength enhancers such as novolac phenolic epoxy resins and cresol novolac epoxy resins, ultraviolet inhibitors, colorants, flame retardants, and foaming agents. The type of nucleating agent is not particularly limited, and examples include inorganic and organic nucleating agents.

[0074] There are no particular limitations on the method for preparing the polyphenylene sulfide resin composition used in the present invention, but a representative example is a method in which the raw materials are fed into a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll, and kneaded at a temperature of 280 to 380°C. The order in which the raw materials are mixed is also not particularly limited, and any of the following methods may be used: a method in which all raw materials are blended and then melt-kneaded by the above-mentioned method; a method in which some raw materials are blended and then melt-kneaded by the above-mentioned method, and then the remaining raw materials are blended and melt-kneaded; or a method in which some raw materials are blended and then the remaining raw materials are mixed using a side feeder while melt-kneading in a single-screw or twin-screw extruder. Furthermore, it is of course possible to add minor additive components to the mixture before molding after the other components have been blended and pelletized by the above-mentioned method or the like.

[0075] The polyphenylene sulfide resin composition thus obtained can be subjected to various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, but is particularly suitable for injection molding.

[0076] In the present invention, a plating layer is formed on a molded article made from the polyphenylene sulfide resin composition, thereby obtaining a plated molded article having a plating layer formed on a portion of the surface of the molded article. It goes without saying that this also includes the case where a plating layer is formed on the entire surface of the molded article. The plating method used in the present invention will be described. A typical electroless plating process for resin molded articles involves a surface treatment step, a catalyst application step, an activation treatment step, and a plating treatment step. The plating treatment step generally involves electroless nickel plating and electroplating.

[0077] The surface treatment process can include a surface activation process and / or a surface roughening process. Regarding the surface roughening process, the method for roughening the surface of a resin molded product can be chemical, mechanical, or physical. However, as mentioned above, due to the excellent chemical resistance of PPS resin, chemical methods often do not provide sufficient roughening. In such cases, mechanical or physical roughening methods are preferred. For example, a method of roughening the surface of a resin molded product using sandpaper or the like is acceptable. However, sandblasting, shot blasting, liquid honing, tumbling, laser irradiation, and the like are preferred, as they offer excellent roughening efficiency, industrial mass production, and quality stability. However, these methods may not provide sufficient roughening for complex shapes, and may even cause the surface to become unnecessarily rough, resulting in a loss of smoothness. The most preferred surface treatment process is a method performed as follows: (a) Irradiate the surface of the molded product with ultraviolet light having a dominant wavelength of 100 to 400 nm for 10 to 120 minutes from a position 5 to 200 mm away from the surface. (b) Thereafter, the molded article treated in (a) above is immersed in an alkaline aqueous solution having a concentration of 5 to 40% by weight for 1 to 30 minutes.

[0078] If the UV light irradiation position is less than 5 mm from the surface of the molded article, excessive surface activation will cause surface deterioration. If it is greater than 200 mm, the irradiation intensity will be weak, resulting in insufficient activation of the molded article surface. Furthermore, an irradiation time of 10 minutes or more will activate the surface and achieve sufficient adhesion of the plating layer. A period of 120 minutes or less is preferred because it does not cause deterioration of the PPS resin surface. While there are no particular limitations on the type of alkaline aqueous solution, an alkaline metal aqueous solution selected from an aqueous solution of alkali metals such as sodium hydroxide, potassium hydroxide, lithium hydroxide, rubinium hydroxide, or cesium hydroxide, and an aqueous solution of tetraalkylammonium hydroxide is preferred, and an aqueous solution selected from an aqueous solution of potassium hydroxide or sodium hydroxide is more preferred. A concentration of the alkaline aqueous solution of 5 wt % or more will ensure sufficient surface roughening. A concentration of 40 wt % or less will prevent excessive surface roughening. Furthermore, the temperature of the alkaline aqueous solution is preferably 40 to 80°C. A temperature of 40° C. or higher can sufficiently roughen the surface, while a temperature of 80° C. or lower can prevent the surface from being excessively roughened. Furthermore, immersion for 1 minute or more can sufficiently roughen the surface, while an immersion time of 30 minutes or less can prevent the surface from being excessively roughened.

[0079] The surface of the molded article obtained in the surface treatment step preferably has pores with a diameter of 0.01 to 2 μm, preferably 0.01 to 1 μm, when observed with a scanning electron microscope. Pores of 0.01 μm or more are preferred because they can exhibit physical adhesion (anchor effect) and provide sufficient adhesion of the plating layer. Pores of 2 μm or less are preferred because they can also suppress surface roughening.

[0080] Next, the step of adsorbing a catalytic metal precursor onto the molded article obtained in the surface treatment step (catalyst application step) and the step of reducing the catalytic metal precursor to a metal (activation treatment step) may be carried out by a general method. ３The catalyst solution was applied to the roughened surface of the molded product, and the concentration was 15 to 25 g / dm ３ The sodium phosphinate solution is used to reduce the palladium dichloride on the PPS resin surface to metal. This method forms metal nuclei that allow smooth deposition of electroless NiP plating.

[0081] Next, the molded article with the metal palladium deposited on its surface obtained in the previous step is subjected to a plating process. This plating process uses chemical copper plating, chemical nickel plating, etc. Further electroplating can be performed after this, making it possible to perform bright nickel plating or copper sulfate plating. Copper plating is particularly useful from the viewpoint of electromagnetic wave shielding.

[0082] The plating layer in the plated molded product obtained in the above process is characterized by having an arithmetic mean roughness Ra of 1.5 μm or less when measured according to a method conforming to JIS-B-0601. It is preferably 1.0 μm or less, and more preferably 0.5 μm or less. A roughness exceeding 1.5 μm is undesirable because it becomes difficult to remove selective frequencies of electromagnetic waves when providing electromagnetic wave shielding properties, etc. The lower limit of the arithmetic mean roughness Ra is preferably as small as possible, but a value of 0.01 μm or more is practical.

[0083] The plated molded article of the present invention allows for the formation of a plating layer with excellent surface smoothness without sacrificing the various properties inherent to PPS resin. Such molded articles are applicable to electrical and electronic components due to the excellent electromagnetic wave shielding properties and surface thermal conductivity provided by the plating layer. In particular, they are capable of preventing mutual interference caused by electromagnetic waves. Due to these properties, the plated molded article of the present invention is preferably applied to the housings of sensor components and ECU (Electronic Control Unit) components.

[0084] Other applications for molded articles made from the polyphenylene sulfide resin composition used in the present invention include electrical and electronic components such as sensors, LED lamps, consumer connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, semiconductors, liquid crystal displays, FDD (Floppy Disk Drive) carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related components; and household and office electrical appliance components such as VTR (Video Tape Recorder) components, television components, irons, hair dryers, rice cooker components, microwave oven components, acoustic components, audio equipment components such as audio, laser discs (registered trademark), and compact discs; lighting components, refrigerator components, air conditioner components, typewriter components, and word processor components. Other applications include office computer parts, telephone parts, facsimile parts, copier parts, cleaning tools, motor parts, lighters, typewriters, and other machinery-related parts; microscopes, binoculars, cameras, watches, and other optical and precision machinery-related parts; server parts used in communications equipment, small cell parts, and radio noise removal parts; valves, alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, various valves such as exhaust gas valves, various pipes for fuel, exhaust, and intake systems, air intake nozzle snorkels, intake manifolds, fuel pumps, exhaust gas sensors, coolant sensors, oil temperature sensors, throttle position sensors, crankshaft position sensors, brake pad wear sensors, air conditioner thermostat bases, air conditioner panel switch boards, fuse connectors, horn terminals, electrical component insulating plates, lamp sockets, lamp reflectors, lamp housings, ignition device cases, vehicle speed sensors, cable liners, and other automobile and vehicle-related parts.

[0085] The present invention will be explained in more detail below by showing examples, but the present invention should not be construed as being limited to the descriptions of these examples.

[0086] [Methods for evaluating the produced PPS resins] (1) Melt flow rate (MFR) The melt flow rate was measured at a temperature of 315° C. under a load of 2160 g in accordance with a method in accordance with ASTM-D1238-70.

[0087] However, for polyphenylene sulfide resins with low viscosity, the MFR was calculated by the following method: The ER of the polyphenylene sulfide resin was measured at a measurement temperature of 315.5°C under a load of 345 g according to a method in accordance with ASTM-D1238-70, and the MFR value was calculated by the following formula (2): MFR = 15.8 x 4.4 x ER.

[0088] Reference Example 1 Polymerization of PPS (PPS-1) A 70-liter autoclave equipped with a stirrer and a bottom stopper valve was charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), and 10.5 kg of ion-exchanged water, and the mixture was gradually heated to 245°C over about 3 hours under atmospheric pressure while passing nitrogen through it. After distilling off 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C.

[0089] The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 moles, including water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 moles per mole of charged alkali metal sulfide. The mixture was then cooled to 200°C, and 10.48 kg (71.27 moles) of p-dichlorobenzene and 9.37 kg (94.50 moles) of NMP were added. The reaction vessel was sealed under nitrogen gas and heated from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting for 100 minutes at 270°C, the bottom stopper valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen. The contents were then stirred for a while at 250°C to remove most of the NMP.

[0090] The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction-filtered through a glass filter. Next, 76 liters of ion-exchanged water heated to 70°C was poured into the glass filter and suction-filtered to obtain a cake.

[0091] The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was purged with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. Thereafter, the autoclave was cooled, and the contents were removed.

[0092] The contents were filtered under suction using a glass filter, and then 76 liters of ion-exchanged water at 70°C was poured into the filter and filtered under suction to obtain a cake. The resulting cake was dried at 120°C under a nitrogen stream to obtain dried PPS. This was heat-treated at 200°C under an oxygen stream until the MFR value reached 150 g / 10 min, yielding crosslinked PPS-1. The MFR of the resulting polymer was 130 g / 10 min.

[0093] Reference Example 2 Polymerization of PPS (PPS-2) A 70-liter autoclave equipped with a stirrer and a bottom stop valve was charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.1 mol) of sodium acetate, and 5.50 kg of ion-exchanged water. The mixture was gradually heated to 245°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. 9.77 kg of water and 0.28 kg of NMP were distilled off, and the reaction vessel was then cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 mol per mole of charged alkali metal sulfide.

[0094] The mixture was then cooled to 200°C, and 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas, and the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm, and the reaction was carried out at 270°C for 140 minutes. Thereafter, 2.40 kg (133 mol) of water was injected while the mixture was cooled from 270°C to 250°C over 15 minutes. The mixture was then gradually cooled from 250°C to 220°C over 75 minutes, after which it was rapidly cooled to near room temperature and the contents were removed.

[0095] The contents were diluted with approximately 35 liters of NMP to form a slurry, which was stirred at 85°C for 30 minutes and then filtered through an 80-mesh wire mesh (mesh opening: 0.175 mm) to obtain a solid. The resulting solid was similarly washed and filtered with approximately 35 liters of NMP. The resulting solid was diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80-mesh wire mesh to recover the solid. This procedure was repeated three times. The resulting solid and 32 g of acetic acid were diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80-mesh wire mesh. The resulting solid was further diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80-mesh wire mesh to recover the solid. The solid thus obtained was dried at 120°C under a nitrogen stream to obtain dried PPS-2. The MFR of the resulting polymer was 300 g / 10 min.

[0096] Reference Example 3 Polymerization of PPS (PPS-3) An autoclave equipped with a stirrer and a bottom valve was charged with 8267.4 g (70.0 mol) of 47.5% sodium hydrosulfide, 2925.0 g (70.2 mol) of 96% sodium hydroxide, 13860.0 g (140.0 mol) of N-methyl-2-pyrrolidone (NMP), 1894.2 g (23.1 mol) of sodium acetate, and 10500.0 g of ion-exchanged water, and gradually heated to 240°C over about 3 hours under atmospheric pressure while passing nitrogen through. After distilling off 14772.1 g of water and 280.0 g of NMP, the reaction vessel was cooled to 160°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.08 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.023 mole per mole of the charged alkali metal sulfide.

[0097] Next, 10,646.7 g (72.4 mol) of p-dichlorobenzene (p-DCB) and 6,444.9 g (65.1 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. With stirring at 240 rpm, the temperature was raised from 200° C. to 270° C. at a rate of 0.6° C. / min and maintained at 270° C. for 70 minutes. The extraction valve at the bottom of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and the contents were stirred for a while at 250° C. to remove most of the NMP.

[0098] The obtained solid and 53 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction-filtered through a glass filter having a pore size of 10 to 16 µm. Next, 60 liters of ion-exchanged water heated to 70°C was poured into the glass filter having a pore size of 10 to 16 µm, and suction-filtered to obtain 18,000 g of PPS resin cake (containing 7,550 g of PPS resin).

[0099] 18,000 g of the PPS resin cake, 40 L of ion-exchanged water, and 43 g of acetic acid were charged into an autoclave equipped with a stirrer. The autoclave was then purged with nitrogen, and the temperature was raised to 192°C and maintained for 30 minutes to perform an acid treatment. The pH during the acid treatment was 7. After cooling the autoclave, the contents were filtered through a glass filter with a pore size of 10-16 μm. Next, 60 L of ion-exchanged water heated to 70°C was poured into the glass filter and suction filtered to obtain a cake. The resulting cake was dried at 120°C for 4 hours under a nitrogen stream to obtain an acid-treated linear PPS. The linear PPS was placed in a 100-L heater equipped with a stirrer and subjected to thermal oxidation treatment at 220°C and an oxygen concentration of 2% for 2 hours to obtain a crosslinked PPS-3. The MFR of the resulting polymer was 5,000 g / 10 min.

[0100] Reference Example 4 Polymerization of PPS (PPS-4) An autoclave equipped with a stirrer and a bottom valve was charged with 8,267.4 g (70.0 mol) of 47.5% sodium hydrosulfide, 2,925.0 g (70.2 mol) of 96% sodium hydroxide, 13,860.0 g (140.0 mol) of N-methyl-2-pyrrolidone (NMP), 1,894.2 g (23.1 mol) of sodium acetate, and 10,500.0 g of ion-exchanged water, and the mixture was gradually heated to 240° C. over approximately 3 hours under atmospheric pressure while passing nitrogen through it. After distilling off 14,772.1 g of water and 280.0 g of NMP, the reaction vessel was cooled to 160° C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.08 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.023 mole per mole of the charged alkali metal sulfide.

[0101] Next, 10,646.7 g (72.4 mol) of p-dichlorobenzene (p-DCB) and 6,444.9 g (65.1 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. With stirring at 240 rpm, the temperature was raised from 200° C. to 270° C. at a rate of 0.6° C. / min and maintained at 270° C. for 70 minutes. The extraction valve at the bottom of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and the contents were stirred for a while at 250° C. to remove most of the NMP.

[0102] The obtained solid and 53 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction-filtered using a glass filter having a pore size of 10 to 16 µm. Next, 60 liters of ion-exchanged water heated to 70°C was poured into the glass filter having a pore size of 10 to 16 µm, and suction-filtered to obtain 18,000 g of a PPS resin cake (containing 7,550 g of PPS resin).

[0103] 18,000 g of the PPS resin cake, 40 L of ion-exchanged water, and 43 g of acetic acid were charged into an autoclave equipped with a stirrer. The inside of the autoclave was purged with nitrogen, and then the temperature was raised to 192°C and maintained for 30 minutes to perform an acid treatment. The pH during the acid treatment was 7. After cooling the autoclave, the contents were filtered through a glass filter with a pore size of 10 to 16 μm. Next, 60 L of ion-exchanged water heated to 70°C was poured into the glass filter and suction filtered to obtain a cake. The resulting cake was dried at 120°C for 4 hours under a nitrogen stream to obtain an acid-treated linear PPS-4. The MFR of the resulting polymer was 6,300 g / 10 min.

[0104] Reference Example 5 Polymerization of PPS (PPS-5) A 70-liter autoclave equipped with a stirrer and a bottom stop valve was charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), and 10.5 kg of ion-exchanged water. The mixture was gradually heated to 245°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. 14.78 kg of water and 0.28 kg of NMP were distilled off, and the reaction vessel was then cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 mol per mole of charged alkali metal sulfide.

[0105] The mixture was then cooled to 200°C, and 10.48 kg (71.27 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas and heated from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting for 100 minutes at 270°C, the bottom stopper valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and the contents were stirred for a while at 250°C to remove most of the NMP.

[0106] The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction-filtered through a glass filter. Next, 76 liters of ion-exchanged water heated to 70°C was poured into the glass filter and suction-filtered to obtain a cake.

[0107] The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was purged with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. Thereafter, the autoclave was cooled, and the contents were removed.

[0108] The contents were suction filtered through a glass filter, and then 76 L of ion-exchanged water at 70°C was poured into the filter and suction filtered to obtain a cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PPS-4. The obtained PPS-5 had an ER of 90 g / 10 min, which was converted to an MFR of 6,257 g / 10 min.

[0109] [Examples 1 to 13, Comparative Examples 1 to 6] Using a twin-screw extruder (TEM-26 manufactured by Toshiba Machine Co., Ltd.) with a 26 mm diameter intermediate addition port and a cylinder temperature set at 320°C and a screw rotation speed set at 400 rpm, (A) polyphenylene sulfide resin, (C) functional group-containing olefin copolymer, and (D) non-fibrous inorganic filler using the PPS resin obtained in Reference Examples 1 to 6 were added through the raw material supply port in the weight ratios shown in Tables 1 and 2 for each Example and Comparative Example, and melted. Then, (B) fibrous filler was supplied through the intermediate addition port and melt-kneaded at a discharge rate of 30 kg / hour to obtain pellets. Using these pellets, various properties were evaluated. The results are shown in Tables 1 and 2.

[0110] [Method of Forming Plated Layer] A plated layer was formed on the molded product by the following method, and its properties were measured.

[0111] (Surface Treatment Step Method 1) A molded product is irradiated with ultraviolet light having dominant wavelengths of 184.9 nm and 253.7 nm for 60 minutes from a height of 30 mm from the surface, and then immersed in a 20% by mass aqueous potassium hydroxide solution at 60°C for 5 minutes.

[0112] (Surface Treatment Step Method 2) The molded product is immersed in a mixed solution of 67.5 mass % concentrated nitric acid and 145 g / L ammonium hydrogen fluoride at 40° C. for 8 minutes, and then neutralized with a 20 g / L aqueous sodium hydroxide solution.

[0113] (Catalyst Application Step to Plating Step) The surface of the molded article obtained in the surface treatment step was immersed in CC-231 (Rhom and Hass) adjusted to 10% by volume with respect to the surface roughened, at 45°C for 2 minutes to condition the surface. ３ The surface of the molded article was roughened by immersion at 45°C for 2 minutes in an aqueous palladium dichloride solution of 19 g / dm ３ The PPS resin was immersed in an aqueous sodium phosphinate solution of 100g at 45°C for 2 minutes to reduce palladium dichloride on the surface of the PPS resin to metal (catalyst application step and activation treatment step).

[0114] Next, the molded article obtained in the above step, on whose surface the metallic palladium was deposited, was subjected to chemical copper plating, and further to bright nickel plating by electroplating.

[0115] The raw materials used in the present invention are listed below.

[0116] (A) Polyphenylene sulfide resin PPS-1: PPS resin polymerized by the method described in Reference Example 1 PPS-2: PPS resin polymerized by the method described in Reference Example 2 PPS-3: PPS resin polymerized by the method described in Reference Example 3 PPS-4: PPS resin polymerized by the method described in Reference Example 4 PPS-5: PPS resin polymerized by the method described in Reference Example 5 (B) Fibrous filler B-1: Chopped strand (T-760H manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 10.5 μm) B-2: Chopped strand (T-747N manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 17.0 μm) (C) Functional group-containing olefin copolymer C-1: Epoxy group-containing polyolefin (Bondfast E manufactured by Mitsui Chemicals, Inc., glycidyl group concentration 3.63 wt%) C-2: Epoxy group-containing polyolefin (Bondfast 7M manufactured by Mitsui Chemicals, Inc., glycidyl group concentration 1.81% by weight) C-3: Epoxy group-containing polyolefin (LOTADER AX8750 manufactured by SK Chemical Polymer, glycidyl group concentration 1.51% by weight) C-4: Hydrogenated styrene-based thermoplastic elastomer (TUFTECH MP10 manufactured by Asahi Kasei Corporation, reactive functional group: amide group) C-5: Hydrogenated styrene-based thermoplastic elastomer (TUFTECH M1913 manufactured by Asahi Kasei Corporation, reactive functional group: acid anhydride group) (D) Non-fibrous inorganic filler D-1: Heavy calcium carbonate (KSS1000 manufactured by Calfine Co., Ltd.) D-2: Heavy calcium carbonate (#800 manufactured by Sankyo Seifun Co., Ltd.) D-3: Heavy calcium carbonate (Super S manufactured by Maruo Calcium Co., Ltd.) D-4: Magnesium hydroxide (Kisuma 5P manufactured by Kyowa Chemical Industry Co., Ltd.) (E) Olefin copolymer containing no functional group E-1: Olefin copolymer (Engage 8842 manufactured by The Dow Chemical Company) Molded articles and plated molded articles made from the resin compositions were evaluated by the following measurement methods.

[0117] (1) Pore size The surface of the molded article after the surface treatment step was observed with a scanning electron microscope (JSM-IT100) manufactured by JEOL Ltd. Secondary electron images were observed at a magnification of 5000 times, and the presence or absence of pores with a diameter of 2 μm or less was confirmed in the obtained images.

[0118] (2) Surface Roughness The surfaces of plated molded articles were measured using a Mitutoyo surface roughness measuring instrument (SV-2100) in accordance with JIS-B-0601 to determine the arithmetic mean roughness Ra. Note that molded articles in which a plated layer itself could not be formed, and articles in which a plated layer was formed but the plated layer was raised, making it difficult to measure the surface roughness, were marked with "-".

[0119] (3) Tensile Strength The tensile strength of a molded article made of a resin composition was measured in accordance with ISO 527-1, 2 (2012). Specifically, the measurement was performed as follows. Pellets of the polyphenylene sulfide resin composition were dried at 130 ° C. for 3 hours using a hot air dryer, and then fed to an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., with a cylinder temperature of 310 ° C. and a mold temperature of 145 ° C., and injection molding was performed using a mold having a Type A1 test piece shape (4 mm thick) specified in ISO 20753 (2008) under conditions where the average speed of the molten resin passing through the cross-sectional area of ​​the central parallel part was 400 ± 50 mm / s to obtain a test piece. The test piece was conditioned for 16 hours at 23°C and 50% relative humidity, and then its tensile strength was measured in accordance with ISO 527-1, -2 (2012) under the conditions of a 23°C, 50% relative humidity atmosphere, a gripper distance of 115 mm, and a test speed of 5 mm / min. The higher this value, the better and more preferable the mechanical strength, and a value of 160 MPa or more is desirable from the viewpoint of versatility.

[0120] (4) Peel Strength The peel strength of the plating layer of plated molded articles was evaluated by the following procedure. First, the polyphenylene sulfide resin composition pellets obtained in the Examples and Comparative Examples were dried for 3 hours at 130°C using a hot air dryer, and then fed into an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., set at a cylinder temperature of 310°C and a mold temperature of 145°C. Test pieces having a square shape with a side length L of 80 mm and a thickness t of 3 mm, as shown in FIG. 1, were molded at an injection speed of 100 mm / s. From these test pieces, strips having a width L2 of 15 mm, a length of 80 mm, and a thickness t of 3 mm were cut out. A plating layer was formed on the cut-out strips using the following method.

[0121] Using a compact ultraviolet irradiation device (Koto Electric, KOL1-300S) equipped with one high-power low-pressure mercury lamp (300 W) having dominant wavelengths of 184.9 nm and 253.7 nm, the test piece was irradiated with ultraviolet light having dominant wavelengths of 184.9 nm and 253.7 nm from a height of 30 mm above the surface for 60 minutes, and then immersed in a 20 wt % aqueous potassium hydroxide solution for 12 minutes to carry out a surface treatment step.

[0122] Next, the roughened molded product obtained in the above step was treated with 0.3 g / dm ３ The catalyst solution was applied to the roughened surface of the molded article, and the catalyst solution was applied to the roughened surface of the molded article. ３ By using the aqueous sodium phosphinate solution of the above, palladium dichloride on the surface of the PPS resin was reduced to metal, thereby forming metal nuclei that allowed smooth deposition of electroless NiP plating (catalyst application step and activation treatment step).

[0123] Next, a chemical copper plating process was carried out using the molded article having metal palladium deposited on its surface obtained in the above process.

[0124] The adhesion strength of the plating layer on the resulting plated molded product was measured according to the adhesion test method in Appendix 1 (norms) of JIS H8630: 2006. A rating of * was given for cases where no plating was formed, D for cases where the peel strength was less than 1 N / cm, C for cases where the peel strength was 1 N / cm or more but less than 3 N / cm, B for cases where the peel strength was 3 N / cm or more but less than 10 N / cm, and A for cases where the peel strength was 10 N / cm or more.

[0125] From Examples 1 and 2 and Comparative Examples 1 to 3, it was found that when the content of (A-1) polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315°C and a load of 2160 g is low, the peel strength of the plating layer is low and the adhesion of the plating layer tends to decrease.

[0126] A comparison of Example 1 with Examples 3 to 7 shows that the addition of a functional group-containing olefin copolymer improves plating properties. In particular, Examples 4 and 5 showed further improvement in the adhesion of the plating layer.

[0127] Furthermore, from the results of Examples 1, 10, and 11, it was found that the amount of (B) fibrous filler added was particularly effective in improving the adhesion of the plating layer when it was 40 to 80 parts by weight per 100 parts by weight of (A) polyphenylene sulfide resin.

[0128] Furthermore, the results of Examples 12 and 13 showed that when a large amount of non-fibrous inorganic filler was added, the pore size after the surface treatment process tended to become larger, and the adhesion of the plating layer tended to decrease.

[0129] Furthermore, the results of Comparative Examples 4 to 6 revealed that if the pore diameter becomes large, the plating layer is not formed.

[0130]

[0131]

[0132] The present invention provides a polyphenylene sulfide resin composition for plating that enables the formation of a plating layer with excellent surface smoothness without sacrificing the various excellent properties inherent to polyphenylene sulfide resin, has excellent adhesion, and can ensure high plating quality even in severe environmental degradation tests such as thermal shock cycle tests; and provides a resin-plated molded product.

[0133] 1 Cut-out portion L1 Width of test piece: 80 mm L2 Width of cut-out test piece: 15 mm t Thickness of test piece: 3 mm

Claims

1. A plated molded article having a plating layer formed on a part or all of a surface of a molded article molded from a polyphenylene sulfide resin composition containing 30 to 200 parts by weight of a fibrous filler (B) per 100 parts by weight of polyphenylene sulfide resin (A), wherein the polyphenylene sulfide resin (A) contains 20% by weight or more of (A-1) a polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315° C. and a load of 2,160 g, when the total amount of the polyphenylene sulfide resin (A) is taken as 100% by weight, and the arithmetic mean roughness of the plating layer surface in the plated molded article is 0.5 μm or less.

2. 2. The plated molded product according to claim 1, wherein the polyphenylene sulfide resin composition further comprises, per 100 parts by weight of the polyphenylene sulfide resin (A), 1 to 30 parts by weight of a functional group-containing olefin copolymer (C) containing at least one functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salt, and an alkoxycarbonyl group.

3. 3. The plated molded product according to claim 1, wherein the polyphenylene sulfide resin (A) contains 50% by weight or more of (A-1) a polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315° C. and a load of 2,160 g, when a total amount of the polyphenylene sulfide resin (A) is taken as 100% by weight.

4. 4. The plated molded product according to claim 2 or 3, characterized in that the functional group contained in the functional group-containing olefinic copolymer (C), which contains at least one functional group selected from a glycidyl group, an acid anhydride group, a carboxyl group and its salt, and an alkoxycarbonyl group, is a glycidyl group, and the glycidyl group concentration in the functional group-containing olefinic copolymer is 1.0 to 4.5% by weight.

5. The method for producing a plated molded product according to any one of claims 1 to 4, characterized in that a molded product produced from the polyphenylene sulfide resin composition is subjected to a surface treatment step, a catalyst application step, an activation treatment step, and a plating treatment step in this order.

6. The method for producing a plated molded product according to claim 5, wherein the surface treatment step is carried out as follows: (a) Irradiating the surface of a molded article with ultraviolet light having a dominant wavelength of 100 to 400 nm for 10 to 120 minutes from a position 5 to 200 mm away from the surface. (b) Thereafter, the molded article treated in (a) is immersed in an alkaline aqueous solution having a concentration of 5 to 40% by mass for 1 to 30 minutes.

7. 7. The method for producing a plated molded product according to claim 5, wherein at least a part of the surface of the molded product after the surface treatment step has pores with a diameter of 2 μm or less.

8. A housing part having the plated molded product according to any one of claims 1 to 4 as a part of its constituent parts.