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

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

[Technical Field]

[0001] The present invention provides plated molded products that have excellent surface smoothness and adhesion, and can ensure high plating quality even in harsh environmental degradation tests such as thermal shock cycle tests, without sacrificing the excellent properties inherent in polyphenylene sulfide resin. [Background technology]

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

[0003] In recent years, sensors and electronic control units have been widely used in all fields, and there is a strong demand for them to have electromagnetic shielding properties to prevent mutual interference and thermal conductivity for thermal management.

[0004] To meet these demands, it has been possible to impart these properties to resin molded products by plating, and this has been put into practical use. However, as mentioned above, PPS resin has good chemical resistance, making plating difficult. In addition, plating PPS resin requires surface roughening by blasting or strong acid, resulting in a high surface roughness of the resulting plated molded product. This raises concerns about losses such as radio wave loss and loss of radio wave directivity, and in practice, its use has been limited. Therefore, there has been a need to improve the plateability (plating properties) of PPS resin and the surface smoothness of the resulting plated molded product.

[0005] Patent Document 1 describes how to improve plating properties by increasing the heat generation during cold crystallization to 5.0 g / J or more, thereby creating a molded product with low surface crystallinity, and further by using a specific primer coating containing activated metal particles, a plated molded product with high adhesion is obtained.

[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 the plating adhesion of PPS resin can be improved by UV irradiation and alkaline etching treatment. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2003-96221 [Patent Document 2] Japanese Patent Application Publication No. 62-270659 [Non-patent literature]

[0009] [Non-Patent Document 1] Surface Technology, 2017, Vol. 68, No. 11, pp. 624-629 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, Patent Document 1 states that molded products with low crystallinity have a poor surface appearance, and in particular, the decorative properties after plating are significantly worsened. Furthermore, when used in a high-temperature environment, changes in the degree of crystallinity occur, causing changes in dimensional properties, and the properties of the resulting plated molded products were not satisfactory. Patent Document 2 states that the inclusion of metallic foreign substances such as potassium titanate significantly impairs the mechanical strength of the molded product. Non-Patent Document 1 shows the effect on unreinforced PPS resin, but for reinforced PPS resin with added inorganic substances such as fibrous fillers, there was a drawback that surface roughness was suppressed, resulting in poor plating adhesion.

[0011] The present invention provides a plated molded product and a method for manufacturing the same that enable the formation of a plated layer with excellent surface smoothness without sacrificing the excellent properties inherent in PPS resin, and that have excellent adhesion to the plated layer, ensuring high plating quality even in harsh environmental degradation tests such as thermal shock cycle tests. [Means for solving the problem]

[0012] The inventors of this invention have conducted extensive research to solve the above problems, and as a result, have arrived at the present invention. In other words, the present invention provides the following:

[0013] (1) A polyphenylene sulfide resin composition comprising (A) 100 parts by weight of polyphenylene sulfide resin and (B) 30 to 200 parts by weight of fibrous filler is used for molding. Furthermore, surface treatment is applied. A plated molded product having a plating layer formed on part or all of the surface of the molded product, wherein the (A) polyphenylene sulfide resin contains 20% by weight or more of (A-1) polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315 degrees Celsius and a load of 2160 g, when the total amount of (A) polyphenylene sulfide resin is 100% by weight, The surface of the molded product subjected to the above surface treatment has pores with a diameter of 0.01 to 2 μm when observed with a scanning electron microscope. A plated molded product having an arithmetic mean roughness of 0.5 μm or less on the surface of the plated layer. (2) The plated molded article according to (1), characterized in that the polyphenylene sulfide resin composition further contains 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 salts, and an alkoxycarbonyl group, per 100 parts by weight of (A) a polyphenylene sulfide resin. (3) The plated molded article according to (1) or (2), characterized in that the (A) polyphenylene sulfide resin contains 50% by weight or more of (A-1) polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315 degrees Celsius and a load of 2160 g, when the total amount of (A) polyphenylene sulfide resin is 100% by weight. (4) The plated molded article according to (2) or (3), characterized in that the functional group contained in the functional group-containing olefin copolymer containing at least one functional group selected from (C) a glycidyl group, an acid anhydride group, a carboxyl group and its salts, and an alkoxycarbonyl group is a glycidyl group, and the concentration of the glycidyl group in the functional group-containing olefin copolymer is 1.0 to 4.5% by weight. (5) A method for manufacturing a plated molded article according to any of (1) to (4) above, characterized in that a surface treatment step, a catalyst application step, an activation treatment step, and a plating treatment step are performed in this order on a molded article formed with the polyphenylene sulfide resin composition. The method for manufacturing a plated molded product having pores with a diameter of 0.01 to 2 μm in at least a portion of the surface of the molded product after the surface treatment step. . (6) The method for manufacturing a plated molded product according to (5), characterized in that the surface treatment step is carried out in the following procedure. (a) Irradiate the molded product with ultraviolet light having a primary wavelength of 100-400 nm from a distance of 5-200 mm from the surface for 10-120 minutes. (b) Then, immerse the molded product treated in (a) in an alkaline aqueous solution with a concentration of 5 to 40% by mass for 1 to 30 minutes. ( 7 A housing component whose constituent part is a plated molded product as described in any of (1) to (4). [Effects of the Invention]

[0014] The present invention enables the formation of a plating layer with excellent surface smoothness without sacrificing the various excellent properties inherent in polyphenylene sulfide resin, has excellent adhesion of the plating layer, and can ensure high plating quality even in severe environmental degradation tests such as a thermal shock cycle test. Provided are a plated molded product and a method for producing the same.

Brief Description of the Drawings

[0015] [Figure 1] It is a test piece for measuring peel strength, where (a) represents a plan view and (b) represents a side view.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described. In the present invention, "weight" means "mass".

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

[0018]

Chemical formula

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

[0020]

Chemical formula

[0021] Next, a method for obtaining the (A) polyphenylene sulfide resin used in the present invention will be described. The PPS resin can be manufactured using known methods comprising a pre-processing step, a polymerization reaction step, a recovery step, and a post-processing step. Regarding the raw materials and pre-processing steps used in the production of the PPS resin, it is preferable to follow the method described in Japanese Patent Application Publication No. 2017-155221. The PPS resin of the present invention preferably contains (A-1) a polyphenylene sulfide resin (hereinafter sometimes abbreviated as "(A-1) high-viscosity PPS resin") having an MFR of 50-600 g / 10 min at 315 degrees Celsius and a load of 2160 g. Methods for obtaining a PPS resin with such properties include manufacturing through important steps described later. For example, a high-viscosity polyphenylene sulfide resin having the above properties can be obtained by using a quenching method in the recovery step described later, or by crosslinking by heat treatment in the presence of oxygen.

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

[0023] [Polymerization reaction process] It is preferable to produce PPS resin by reacting a sulfidating agent and a polyhalogenated aromatic compound in an organic polar solvent at a temperature range of 200 to 290°C.

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

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

[0026] Generally, the temperature is eventually raised to 250-290°C, and the reaction is carried out at that temperature for typically 0.25-50 hours, preferably 0.5-20 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, followed by raising the temperature to 270°C 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 in the range of 0.25 to 20 hours, preferably in the range of 0.25 to 10 hours.

[0028] Furthermore, to obtain polymers with a higher degree of polymerization, it is effective to carry out the polymerization reaction in multiple steps. When carrying out the polymerization reaction in multiple steps, it is effective to proceed to the next step when the conversion rate of the polyhalogenated aromatic compound in the system at 245°C reaches 40 mol% or more, preferably 60 mol%.

[0029] [Recovery Process] After the polymerization reaction process is complete, solid material is recovered from the polymerization reaction product, which includes the polymer and solvent.

[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. The flash method involves heating the polymerization reaction product at high temperature and high pressure (usually 250°C or higher, 8 kg / cm³). 2 This method involves flashing the mixture from the above state into an atmosphere of normal or reduced pressure, recovering the solvent and simultaneously recovering the polymer in powder form. In this context, flashing refers to ejecting the polymerization reaction product from a nozzle. The medium used for flashing is, for example, nitrogen or water vapor at normal pressure, and the temperature used for flashing is usually selected to be in the range of 150°C to 250°C.

[0031] The flash method is an economically advantageous recovery method because it allows for the recovery of solid material simultaneously with the solvent, and the recovery time is relatively short. In this recovery method, ionic compounds such as sodium and low-molecular-weight organic polymers (oligomers) tend to be easily incorporated into the polymer during the solidification process.

[0032] However, the method for recovering the PPS resin used in the manufacturing method of the present invention is not limited to the flash method. Any method that satisfies the requirements of the present invention may be used, such as a method of slowly cooling a polymerization reaction product containing a polymer and a solvent to recover particulate polymer (quench method). However, from an economic standpoint, it is more preferable to use PPS resin recovered by the flash method.

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

[0034] The acid used in the acid treatment in this invention is not particularly limited as long as it does not have the effect of decomposing the PPS resin, and examples include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonate, and propyl acid. Among these, acetic acid and hydrochloric acid are more preferably used, but those that decompose and degrade the PPS resin, such as nitric acid, are undesirable.

[0035] When using an aqueous solution of acid, the water is preferably distilled water or deionized water. The aqueous solution of acid is preferably pH 1 to 7, and more preferably pH 2 to 4. A pH of 7 or lower is preferable because it does not increase the amount of metal contained in the PPS resin. A pH of 1 or higher is also preferable because it suppresses the amount of volatile components contained in the PPS resin.

[0036] The acid treatment method preferably involves immersing the PPS resin in an acid or an aqueous solution of acid, and stirring and heating may be performed 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. Below 80°C, the acid treatment effect is small and the metal content increases, and above 250°C, the pressure becomes too high, which is undesirable for safety reasons. Furthermore, the pH when the PPS resin is treated by immersion in an aqueous solution of acid is preferably less than 8, and more preferably pH 2 to 8. By keeping the pH at 8 or below, the amount of metal contained in the resulting PPS resin does not increase, which is preferable.

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

[0038] In acid treatment, the ratio of PPS resin to acid or an aqueous acid solution is preferably such that the PPS resin is fully immersed in the acid or aqueous acid solution. For every 500g of PPS resin, the amount of acid or aqueous acid solution is preferably 0.5 to 500L, more preferably 1 to 100L, and even more preferably 2.5 to 20L. Using 0.5L or more of acid or aqueous acid solution per 500g of PPS resin ensures that the PPS resin is fully immersed in the solution, preventing poor cleaning and avoiding an increase in the amount of metal contained in the PPS resin. Conversely, using 500L or less of acid or aqueous acid solution per 500g of PPS resin is also preferable because it prevents a significant decrease in production efficiency due to an excessive amount of acid or aqueous acid solution used relative to the PPS resin.

[0039] These acid treatments are carried out by methods such as adding a predetermined amount of PPS resin to a predetermined amount of water and acid, heating and stirring in a pressure vessel, or continuously performing the acid treatment. A simple method for separating the aqueous solution and the PPS resin from the treatment solution after acid treatment is filtration using sieves or filters, with examples including natural filtration, pressure filtration, vacuum filtration, and centrifugal filtration. To remove residual acid and impurities from the surface of the PPS resin separated from the treatment solution, it is preferable to wash it several times with water or warm water. Washing methods include filtering while applying water to the PPS resin on a filtration device, or separating the aqueous solution and the PPS resin by adding the separated PPS resin to pre-prepared water and then filtering again. The water used for washing is preferably distilled water or deionized water. While the structure of the end products of the acid-treated PPS resin is thought to change, it is difficult to represent the structure of the PPS resin obtained by acid treatment with a general formula, nor is it difficult to identify it by its properties. Therefore, it can only be identified through the process (acid treatment) used to obtain the PPS resin.

[0040] [Post-treatment process (hot water treatment)] In this invention, it is preferable to perform a hot water treatment before the acid treatment step, and the method is as follows. The water used for the hot water treatment in this 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. Setting the temperature to 80°C or higher allows the hot water treatment effect to be fully exerted and suppresses the amount of volatile gas generated. Setting the temperature to 250°C or lower suppresses the rise in pressure, which is preferable from a safety standpoint.

[0041] The duration of the hot water treatment should preferably be long enough to allow sufficient extraction of the PPS resin with hot water. When treating at 80°C, 2 to 24 hours is preferred, and when treating at 200°C, 0.01 to 5 hours is preferred.

[0042] In the hot water treatment, the ratio of PPS resin to hot water is preferably such that the PPS resin is fully immersed in the hot water. For every 500g of PPS resin, 0.5 to 500L of water is preferred, 1 to 100L is more preferred, and 2.5 to 20L is even more preferred. Using 0.5L or more of hot water per 500g of PPS resin is preferable because it ensures the PPS resin is fully immersed in the hot water, preventing inadequate cleaning and preventing an increase in the amount of volatile gases generated. Using 500L or less of hot water per 500g of PPS resin is also preferable because it prevents a significant excess of water relative to the PPS resin, thus avoiding a substantial decrease in production efficiency.

[0043] There are no particular restrictions on these hot water treatment operations, and they can be carried out by adding a predetermined amount of PPS resin to a predetermined amount of water and heating and stirring in a pressure vessel, or by continuously applying hot water treatment. There are no particular restrictions on the method of separating the aqueous solution and PPS resin from the treatment solution after hot water treatment, but filtration using a sieve or filter is simple, and examples of methods include natural filtration, pressure filtration, vacuum filtration, and centrifugal filtration. To remove impurities remaining on the surface of the PPS resin separated from the treatment solution, it is preferable to wash it several times with water or warm water. There are no particular restrictions on the washing method, but examples of methods to separate the aqueous solution and PPS resin include filtering while pouring water over the PPS resin on a filtration device, or adding the separated PPS resin to pre-prepared water and then filtering again. The water used for washing is preferably distilled water or deionized water.

[0044] Furthermore, since decomposition of PPS terminal groups during these acid treatments and hot water treatments is undesirable, it is desirable to carry out the acid treatments and hot water treatments under an inert atmosphere. Examples of inert atmospheres include nitrogen, helium, and argon, but from an economic standpoint, a nitrogen atmosphere is preferred.

[0045] [Post-treatment process (washing with organic solvent)] The present invention may include a step of washing the PPS resin with an organic solvent before the steps of acid treatment or hot water treatment, and the method is as follows. The organic solvent used for washing the PPS resin in the present invention is not particularly limited as long as it does not have the effect of decomposing the PPS resin, for example, nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphorusamide, piperadinons, sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, sulfolane, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, dimethyl ether, dipropyl ether, dioxane, tetrahydrogenase Examples of suitable 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, the use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform is particularly preferred. These organic solvents may be used individually or in mixtures of two or more.

[0046] Methods for cleaning with organic solvents include immersing the PPS resin in the organic solvent, and stirring or heating can be performed as needed. There are no particular restrictions on the cleaning temperature when cleaning PPS resin with organic solvents; any temperature from room temperature to approximately 300°C can be selected. Cleaning efficiency tends to increase with higher cleaning temperatures, but usually sufficient results can be obtained at cleaning temperatures from room temperature to 150°C. It is also possible to clean 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 cleaning time. Depending on the cleaning conditions, sufficient results can usually be obtained by cleaning for 5 minutes or more in the case of batch cleaning. Continuous cleaning is also possible.

[0047] These acid treatments, hot water treatments, or cleaning with organic solvents can also be carried out in appropriate combinations.

[0048] [Heat treatment process] In this invention, by further heat-treating the PPS resin after the above post-treatment step, the molecular chains become cross-linked with each other, resulting in a PPS resin with high mechanical strength and excellent dimensional stability. By using this heat treatment step, the (A-1) high-viscosity PPS resin described above can be easily obtained. The heat treatment step will be described in detail below.

[0049] In the present invention, heat treatment can be performed to obtain a PPS resin with high mechanical strength. However, excessive heat treatment is undesirable because it reduces melt fluidity and increases gelled substances in the resin, leading to problems such as 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 the antifreeze resistance also tends to decrease. According to the heat treatment of the present invention, it is possible to obtain a PPS resin with improved mechanical strength while suppressing the generation of gelled substances without impairing melt fluidity.

[0050] Heat treatment can be performed under both high and low oxygen concentration atmospheres, provided that the heat treatment temperature and time are within a specific range.

[0051] For a high oxygen concentration atmosphere, it is preferable that the oxygen concentration exceeds 2 volume%, and the heat treatment temperature should be 160-270°C, with a heat treatment time of 0.1-17 hours. However, while high oxygen concentration conditions reduce volatile components quickly, they also cause rapid oxidation crosslinking, making gel formation more likely. Therefore, it is generally preferable to perform heat treatment at low temperatures for long periods or at high temperatures for short periods. For specific conditions of low-temperature, long-period heat treatment, it is preferable to heat at 160°C to 210°C for 1 to 17 hours, and more preferably at 170°C to 200°C for 1 to 10 hours. Heat treatment at temperatures below 160°C results in a small reduction in volatile components and a small improvement in mechanical strength. Furthermore, even at low temperatures, under conditions where the oxygen concentration exceeds 2 volume%, if the heat treatment time exceeds 17 hours, oxidation crosslinking progresses, making gel formation more likely. The specific conditions for high-temperature, short-time heat treatment are preferably between 210°C and 270°C for 0.1 hours or more but less than 1 hour, and more preferably between 220°C and 260°C for 0.2 to 0.8 hours. If the heat treatment temperature exceeds 270°C, oxidative crosslinking proceeds rapidly, making it easier for gels to form. Also, even at high temperatures, if the heat treatment time is less than 0.1 hours, the effect of reducing volatile components is small, and the effect of improving mechanical strength is small.

[0052] For low oxygen concentration atmosphere conditions, it is preferable that the oxygen concentration is 2% by volume or less, the heat treatment temperature is preferably 210-270°C, and the heat treatment time is preferably 0.2-50 hours. Since a lower 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 it is more preferable to perform it for 2-20 hours under heat treatment temperature conditions of 220-260°C. If the heat treatment time is below 210°C, the amount of volatile components in the PPS resin is not reduced, and the effect of improving mechanical strength is small, and if the heat treatment time exceeds 50 hours, productivity decreases.

[0053] The heating device applicable to the heat treatment of the present invention may be a conventional hot air dryer, or a rotary or agitator-equipped heating device. However, for efficient and more uniform processing, a rotary or agitator-equipped heating device is more preferable, and examples include paddle dryers, fluidized bed dryers, KID dryers, steam tube dryers, and even inclined disc 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, it is acceptable to mix oxidizing gases such as oxygen, air, and ozone with non-oxidizing inert gases such as nitrogen, argon, helium, and water vapor. As long as the heat treatment can be performed within the heating device, there are no particular restrictions on the location from which the oxidizing gas or inert gas is introduced (top, bottom, or side) of the heating device. However, a simpler method is to introduce the gas from the top of the heating device. Furthermore, the oxidizing gas and inert gas may be mixed before introducing them into the heating device, or they may be mixed separately from different locations in the heating device.

[0054] Although the structure of the PPS resin is thought to change after the heat treatment process, the PPS resin obtained after heat treatment has a complex and diverse structure, making it impractical to specify the structure of the PPS resin in question. By undergoing the heat treatment process, volatile components and moisture contained in the PPS resin can be removed, resulting in a PPS resin with excellent mechanical strength and dimensional stability.

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

[0056] The PPS resin used in the present invention preferably contains 20% by weight or more of (A-1) PPS resin with an MFR of 50 to 600 g / 10 min, when (A) polyphenylene sulfide resin is 100% by weight, and more preferably 50% by weight or more from the viewpoint of improving plating properties. When the MFR is 50 g / 10 min or more, it is preferable that the moldability does not deteriorate. When the MFR is 600 g / 10 min or less, it is preferable that the plating layer does not not form or the adhesion of the plating layer does not deteriorate. It is more preferable that the MFR is 100 to 500 g / 10 min. Here, the MFR is the value measured according to ASTM-D1238-70 under the conditions of 315 degrees Celsius and a load of 2160 g. It is preferable that the plating properties are further improved by containing 50% by weight or more of (A-1) high viscosity PPS resin in 100 parts by weight of (A) polyphenylene sulfide resin. Furthermore, the upper limit for the content of (A-1) high-viscosity PPS resin in (A) polyphenylene sulfide resin is 100% by weight, which is most preferable, i.e., using only (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 fibers, glass milled fibers, glass flat fibers, irregularly shaped cross-section glass fibers, glass cut fibers, stainless steel fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers and Kevlar fibril, gypsum fibers, ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, and the like.

[0058] (B) Among fibrous fillers, it is preferable to use at least one type selected from glass fibers, glass milled fibers, glass flat fibers, and irregularly shaped cross-section glass fibers based on their mechanical properties and dimensional properties. The glass fibers and other fillers used in the present invention may also be used after their surfaces have been treated with known coupling agents (e.g., silane-based coupling agents, titanate-based coupling agents, etc.) or other surface treatments.

[0059] The amount of fibrous filler (B) in the polyphenylene sulfide resin composition must be 30 to 200 parts by weight of fibrous filler (B) per 100 parts by weight of polyphenylene sulfide resin (A), considering the balance between heat resistance and mechanical properties. More preferably, it is 40 to 150 parts by weight, and even more preferably 50 to 110 parts by weight. If the amount is less than 30 parts by weight, the coefficient of linear expansion of the PPS resin is large, and the difference in linear expansion with the metal forming the plating layer becomes large, so the stress generated during heat cycling becomes large, and adhesion tends to deteriorate. If it exceeds 200 parts by weight, excessive surface roughening occurs, and the anchoring effect during plating cannot be expected, so adhesion tends to deteriorate.

[0060] Next, the polyphenylene sulfide resin composition used in the present invention preferably contains a functional group-containing olefin copolymer (hereinafter sometimes abbreviated as "(C) functional group-containing olefin copolymer") which contains at least one functional group selected from (C) glycidyl groups, acid anhydride groups, carboxyl groups and their salts, and alkoxycarbonyl groups. (C) Functional group-containing olefin copolymers are obtained by introducing monomer components (functional group-containing components) having functional groups such as glycidyl groups, acid anhydride groups, and ionomers into olefin polymers and / or olefin copolymers. Examples of functional group-containing components include monomers containing acid anhydride groups 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 glycidyl groups such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconic acid, and glycidyl citraconic acid; and monomers containing ionomers such as carboxylic acid metal complexes.

[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 two or more; and copolymers of α-olefins with α,β-unsaturated acids such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, and their alkyl esters. Specific examples include ethylene / propylene copolymer ("A / B" indicates a copolymer of A and B, the same applies hereinafter), ethylene / butene-1 copolymer, ethylene / hexene-1 copolymer, ethylene / octene-1 copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, and ethylene / butyl methacrylate copolymer. Among the functional groups, it is preferable to include a glycidyl group from the viewpoint of improving plating properties.

[0062] There are no particular restrictions on the method of introducing functional group-containing components into these olefin copolymers. Methods such as copolymerizing them when copolymerizing an olefin copolymer similar to the one used as the olefin copolymer, or introducing them into an olefin copolymer by graft copolymerization using a radical initiator, can be used. Particularly useful examples of olefin copolymers obtained by introducing monomer components having functional groups such as glycidyl groups, acid anhydride groups, and ionomers into an olefin copolymer include: ethylene / propylene-g-glycidyl methacrylate copolymer ("g" represents graft, the same applies hereafter), ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, and ethylene / propylene-g-glycidyl anhydride copolymer. Leic acid copolymers, ethylene / butene-1-g-maleic anhydride copolymers, ethylene / methyl acrylate-g-maleic anhydride copolymers, ethylene / ethyl acrylate-g-maleic anhydride copolymers, ethylene / methyl methacrylate-g-maleic anhydride copolymers, ethylene / ethyl methacrylate-g-maleic anhydride copolymers, zinc complexes of ethylene / methacrylic acid copolymers, magnesium complexes of ethylene / methacrylic acid copolymers, sodium complexes of ethylene / methacrylic acid copolymers, or glycidyl esters of α-olefins such as ethylene and propylene with α,β-unsaturated acids are preferably used. The functional group-containing component is most preferably a glycidyl group, and the glycidyl group concentration is appropriately in the range of 1.0 to 4.0% by weight, preferably 1.1 to 3.9% by weight. The glycidyl group concentration of the functional group-containing olefin copolymer (C) is calculated from the following formula (1). A concentration of 1.0% by weight or more improves compatibility with PPS resin and increases mechanical properties. By keeping the amount below 4.0% by weight, the adhesion of the plating layer is improved. Formula (1) Glycidyl group concentration (weight %) = A × A M / Gly M A [weight %]: 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] Here, the glycidyl group-containing component refers to the repeating unit that contains a glycidyl group among the repeating units that make up the functional group-containing olefin copolymer.

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

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

[0066] (D) The content of the 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 (A) polyphenylene sulfide resin, from the viewpoint of balancing plating adhesion, heat resistance, and mechanical properties. A content of 0.5 parts by weight or more allows for obtaining the surface roughness required during plating. A content of 60 parts by weight or less prevents the surface from becoming excessively rough during chemical treatment in the plating process, thus maintaining adhesion of the plating layer.

[0067] Furthermore, the ratio Y / X of the blending weight X of (D) non-fibrous inorganic filler to the blending weight Y of (B) fibrous filler, relative to 100 parts by weight of (A) polyphenylene sulfide resin, is 2 or more, preferably 3 or more. When it is 2 or more, the surface does not become excessively rough during the chemical treatment in the plating process, and the adhesion of the plating layer can be maintained.

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

[0069] (E) The content of the olefin copolymer that does not contain functional groups is preferably 1 to 3 parts by weight, and particularly preferably 0 to 1.5 parts by weight, per 100 parts by weight of (A) polyphenylene sulfide resin. Adding 1 part by weight or more is preferable because it dramatically improves heat cycle resistance. Using 3 parts by weight or less is preferable because it improves heat cycle resistance while maintaining dimensional stability.

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

[0071] (F) The content of the silane compound is preferably 0.1 to 3 parts by weight of (F) the silane compound per 100 parts by weight of (A) polyphenylene sulfide resin. By keeping it within this range, it is possible to achieve both excellent fluidity and weld strength.

[0072] Furthermore, the polyphenylene sulfide resin composition used in the present invention may be a blend of (A) polyphenylene sulfide resin, (C) functional group-containing olefin copolymer, and (E) olefin copolymer that does not contain functional groups, to the extent that the effects of the present invention are not impaired. There are no particular limitations on the blendable resins, but 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; polyamide-imide, polyacetal, polyimide, polyetherimide, polyethersulfone, modified polyphenylene ether resin, polysulfone resin, polysulfone resin, polyallyl sulfone resin, polyketone resin, polyarylate resin, liquid crystal polymer, polyetherketone resin, polythioetherketone resin, polyetheretherketone resin, and tetrafluoroethylene resin.

[0073] Furthermore, the polyphenylene sulfide resin composition used in the present invention may contain other components, such as antioxidants and heat stabilizers (hindered phenol, hydroquinone, phosphorus, phosphite, amine, sulfur, and their substituted derivatives, etc.), weathering agents (resorcinol, salicylate, benzotriazole, benzophenone, hindered amine, etc.), mold release agents and lubricants (montanic acid and its metal salts, its esters, its half-esters, stearyl alcohol, stearamide, stearat, bisurea, and polyethylene wax, etc.), pigments (cadmium sulfide, phthalocyanine, coloring carbon black, etc.), dyes (nigrosine, etc.), nucleating agents (inorganic or organic nucleating agents such as talc, silica, kaolin, and clay), and plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.). Conventional additives such as antistatic agents (alkyl sulfate anionic antistatic agents, quaternary ammonium salt cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine-based amphoteric antistatic agents, etc.), 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 resin, or combinations of these brominated flame retardants with antimony trioxide, etc.), heat stabilizers, lubricants such as calcium stearate, aluminum stearate, and lithium stearate, strength enhancers such as novolac phenol type epoxy resin and cresol novolac type epoxy resin, UV inhibitors, colorants, flame retardants, and foaming agents can be added. There are no particular restrictions on the type of nucleating agent, but examples include inorganic nucleating agents and organic nucleating agents.

[0074] There are no particular restrictions on the method for preparing the polyphenylene sulfide resin composition used in the present invention, but typical examples include supplying each raw material to a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and kneading them at a temperature of 280 to 380°C. There are no particular restrictions on the mixing order of the raw materials, and any of the following methods may be used: a method in which all raw materials are blended and then melt-kneaded using the method described above; a method in which some raw materials are blended and then melt-kneaded using the method described above, and then the remaining raw materials are blended and melt-kneaded again; 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 is performed with a single-screw or twin-screw extruder. Furthermore, for small amounts of additive components, it is of course possible to knead other components using the method described above to form pellets, and then add them before molding.

[0075] The polyphenylene sulfide resin composition obtained in this manner can be used in various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, but is particularly suitable for injection molding applications.

[0076] In this invention, a plating layer is formed on a molded product made from the polyphenylene sulfide resin composition, and a plated molded product is obtained in which a plating layer is formed on a part of the surface of the molded product. It goes without saying that this also includes the case in which a plating layer is formed on the entire surface of the molded product. The plating method used in this invention will now be described. A general electroless plating process for resin molded products consists of 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 includes a surface activation process and / or a surface roughening process. Regarding the surface roughening process, the method for roughening the surface of the resin molded product may be chemical, mechanical, or physical. However, as mentioned above, PPS resin has excellent chemical resistance, so 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 the resin molded product using sandpaper may be used. However, sandblasting, shot blasting, liquid honing, tumbling, and laser irradiation are preferred because they offer superior roughening efficiency, industrial mass production capabilities, and quality stability. However, with these methods, roughening may be insufficient in the case of complex shapes, and furthermore, the surface may be roughened more than necessary, potentially impairing smoothness. The most preferred surface treatment process is the method performed in the following procedure. (a) Irradiate the molded product with ultraviolet light having a main wavelength of 100-400 nm from a position 5-200 mm away from the surface for 10-120 minutes. (b) Subsequently, the molded product treated in (a) is immersed in an alkaline aqueous solution with a concentration of 5-40% by weight for 1-30 minutes.

[0078] If the irradiation position of ultraviolet light is less than 5 mm from the surface of the molded product, excessive surface activation will cause surface degradation. If it is greater than 200 mm, the irradiation intensity is too weak, resulting in insufficient activation of the molded product surface. Furthermore, by irradiating for 10 minutes or more, the surface is activated and sufficient adhesion of the plating layer can be obtained. Using 120 minutes or less is preferable as it does not degrade the PPS resin surface. There are no particular limitations on the type of alkaline aqueous solution, but it is preferably an alkali metal aqueous solution selected from alkali metal aqueous solutions such as sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, lithium hydroxide aqueous solution, rubinium hydroxide aqueous solution, cesium hydroxide aqueous solution, and tetraalkylammonium hydroxide aqueous solution, and more preferably an aqueous solution selected from potassium hydroxide aqueous solution and sodium hydroxide aqueous solution. A concentration of 5% by weight or more of the alkaline aqueous solution can sufficiently roughen the surface. Using 40% by weight or less will not excessively roughen the surface. Furthermore, the temperature of the alkaline aqueous solution is preferably 40 to 80°C. By setting the temperature above 40°C, sufficient surface roughening can be achieved, while setting it below 80°C prevents excessive surface roughening. Furthermore, immersion for more than one minute also achieves sufficient surface roughening, while immersion for 30 minutes or less prevents excessive surface roughening.

[0079] The surface of the molded product obtained in the above surface treatment step preferably has pores with a diameter of 0.01 to 2 μm, more preferably 0.01 to 1 μm, when observed with a scanning electron microscope. Having pores of 0.01 μm or larger is preferable because it allows for physical adhesion (anchoring effect) and ensures sufficient adhesion of the plating layer. Having pores of 2 μm or less is preferable because it suppresses surface roughening.

[0080] Next, the process of adsorbing a catalyst metal precursor onto the molded product obtained in the surface treatment process (catalyst application process) and the process of reducing the catalyst metal precursor to metal (activation treatment process) can be carried out using general methods. For example, 0.1~0.5 g / dm 3A palladium dichloride aqueous solution is used as a catalyst solution and applied to the roughened surface of the molded product at a rate of 15-25 g / dm 3 By using an aqueous sodium phosphinate solution, the palladium dichloride on the surface of the PPS resin is reduced to metal. This method forms a metallic nucleus that facilitates the smooth deposition of electroless NiP plating.

[0081] Next, a plating process is carried out using the molded product on which the metallic palladium obtained in the previous step has been deposited on its surface. Chemical copper plating, chemical nickel plating, etc., are used in this plating process. Furthermore, by applying electroplating afterward, it is possible to achieve bright nickel plating or copper sulfate plating. From the viewpoint of electromagnetic shielding, copper plating is particularly useful.

[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 by a method conforming to JIS-B-0601. Preferably, it is 1.0 μm or less, and more preferably 0.5 μm or less. If it exceeds 1.5 μm, it becomes difficult to remove the selective frequency of electromagnetic waves when performing electromagnetic wave shielding, so this is undesirable. The lower limit of the arithmetic mean roughness Ra is preferable as it is smaller, but 0.01 μm or more is practical.

[0083] The plated molded product of the present invention makes it possible to form a plated layer with excellent surface smoothness without sacrificing the various properties inherent in PPS resin. Because such a molded product has excellent electromagnetic shielding properties and surface thermal conductivity due to the plated layer, it can be applied to electrical and electronic components. In particular, it can prevent mutual interference caused by electromagnetic waves. Due to these properties, the plated molded product of the present invention is preferably applied to housings for sensor components and ECU (Electronic Control Unit) components.

[0084] Other applicable applications for molded articles made from the polyphenylene sulfide resin composition used in this invention include, for example, 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 crystals, FDD (Floppy Disk Drive) carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related parts; as well as household and office electrical product parts such as VTR (Video Tape Recorder) parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio, laser discs (registered trademark), and compact discs; lighting parts, refrigerator parts, air conditioner parts, typewriter parts, and word processor parts. Other applications include mechanical parts such as office computer components, telephone components, facsimile components, photocopier components, cleaning jigs, motor components, lighters, and typewriters; optical equipment such as microscopes, binoculars, cameras, and watches; precision machinery components; server components, small cell components, and radio noise reduction components used in communication equipment; valve alternator terminals, alternator connectors, IC regulators, light dew potentiometer bases, exhaust gas valves and other various 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 boards; lamp sockets; lamp reflectors; lamp housings; ignition device cases; vehicle speed sensors; cable liners and other automotive and vehicle-related components. [Examples]

[0085] The present invention will be further described below with reference to examples, but the present invention is not to be construed as being limited to the descriptions in these examples.

[0086] [Evaluation method for manufactured PPS resin] (1) Melt Flow Rate (MFR) The measurement was performed at a temperature of 315°C and under a load of 2160g, following the method compliant with ASTM-D1238-70.

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

[0088] [Reference Example 1] Polymerization of PPS (PPS-1) In a 70-liter autoclave equipped with a stirrer and a bottom valve, 8.27 kg (70.00 mol) of 47.5% sodium hydroxide, 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 deionized water were charged. The mixture was gradually heated to 245°C over approximately 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 residual water in the system per mole of alkali metal sulfide added was 1.06 moles, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 moles per mole of alkali metal sulfide added. 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 the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting at 270°C for 100 minutes, the bottom valve of the autoclave was opened, and the contents were flushed into a stirrer-equipped container over 15 minutes under pressurized nitrogen. The mixture was then stirred at 250°C for a while to remove most of the NMP.

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

[0091] The resulting cake and 90 liters of deionized water were placed in an autoclave equipped with a stirrer, and acetic acid was added to bring the pH to 7. After purging the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes. The autoclave was then cooled and the contents were removed.

[0092] The contents were filtered by suction using a glass filter, and then 76 liters of ion-exchanged water at 70°C were poured into it and filtered by suction to obtain a cake. The obtained 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 to obtain cross-linked PPS-1. The MFR of the obtained polymer was 130 g / 10 min.

[0093] [Reference Example 2] Polymerization of PPS (PPS-2) In a 70-liter autoclave equipped with a stirrer and bottom valve, 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 deionized water were charged. The mixture was gradually heated to 245°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. After distilling off 9.77 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of residual water in the system per mole of 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 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. The reaction was carried out at 270°C for 140 minutes. Subsequently, 2.40 kg (133 mol) of water was injected under pressure while the mixture cooled from 270°C to 250°C over 15 minutes. After that, the mixture was gradually cooled from 250°C to 220°C over 75 minutes, then 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. The slurry was then filtered through an 80-mesh wire mesh (mesh opening 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with approximately 35 liters of NMP. The obtained solid was diluted with 70 liters of deionized water, stirred at 70°C for 30 minutes, and filtered through an 80-mesh wire mesh to recover the solid. This process was repeated a total of three times. The obtained solid and 32 g of acetic acid were diluted with 70 liters of deionized water, stirred at 70°C for 30 minutes, and filtered through an 80-mesh wire mesh. The obtained solid was then diluted with 70 liters of deionized water, stirred at 70°C for 30 minutes, and filtered through an 80-mesh wire mesh to recover the solid. The solid thus obtained was dried under a nitrogen stream at 120°C to obtain dried PPS-2. The MFR of the obtained polymer was 300 g / 10 min.

[0096] [Reference Example 3] Polymerization of PPS (PPS-3) In an autoclave equipped with a stirrer and a valve at the bottom, 8267.4 g (70.0 mol) of 47.5% sodium hydroxide, 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 deionized water were charged. The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. 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 residual water in the system per mole of alkali metal sulfide was 1.08 moles, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.023 moles per mole of alkali metal sulfide.

[0097] Next, 10646.7 g (72.4 mol) of p-dichlorobenzene (p-DCB) and 6444.9 g (65.1 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm, and held at 270°C for 70 minutes. The withdrawal valve at the bottom of the autoclave was opened, and the contents were flushed into a stirrer-equipped container over 15 minutes under pressurized nitrogen. The mixture was then stirred at 250°C for a while to remove most of the NMP.

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

[0099] 18,000 g of the aforementioned PPS resin cake, 40 liters of deionized water, and 43 g of acetic acid were placed in an autoclave equipped with a stirrer. After replacing the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes to perform the acid treatment. The pH during the acid treatment was 7. After the autoclave cooled, the contents were filtered through a glass filter with a pore size of 10-16 μm. Next, 60 liters of deionized water heated to 70°C were poured into the glass filter and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream for 4 hours to obtain acid-treated linear PPS. Linear PPS was placed in a 100-liter heating device with a stirrer and subjected to thermal oxidation treatment at 220°C with an oxygen concentration of 2% for 2 hours to obtain crosslinked PPS-3. The MFR of the obtained polymer was 5000 g / 10 min.

[0100] [Reference Example 4] Polymerization of PPS (PPS-4) In an autoclave equipped with a stirrer and a valve at the bottom, 8267.4 g (70.0 mol) of 47.5% sodium hydroxide, 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 deionized water were charged. The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. 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 residual water in the system per mole of alkali metal sulfide was 1.08 moles, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.023 moles per mole of alkali metal sulfide.

[0101] Next, 10646.7 g (72.4 mol) of p-dichlorobenzene (p-DCB) and 6444.9 g (65.1 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm, and held at 270°C for 70 minutes. The withdrawal valve at the bottom of the autoclave was opened, and the contents were flushed into a stirrer-equipped container over 15 minutes under pressurized nitrogen. The mixture was then stirred at 250°C for a while to remove most of the NMP.

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

[0103] 18,000 g of the aforementioned PPS resin cake, 40 liters of deionized water, and 43 g of acetic acid were placed in an autoclave equipped with a stirrer. After purging the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes to perform acid treatment. The pH during acid treatment was 7. After the autoclave cooled, the contents were filtered through a glass filter with a pore size of 10-16 μm. Next, 60 liters of deionized water heated to 70°C were poured into the glass filter and filtered by suction to obtain the cake. The obtained cake was dried under a nitrogen stream at 120°C for 4 hours to obtain linear PPS-4 that had been acid-treated. The MFR of the obtained polymer was 6300 g / 10 min.

[0104] [Reference Example 5] Polymerization of PPS (PPS-5) In a 70-liter autoclave equipped with a stirrer and bottom valve, 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 deionized water were charged. The mixture was gradually heated to 245°C over approximately 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. The amount of residual water in the system per mole of alkali metal sulfide was 1.06 moles, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 moles per mole of 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 the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting at 270°C for 100 minutes, the bottom valve of the autoclave was opened, and the contents were flushed into a stirrer-equipped container over 15 minutes under pressurized nitrogen. The mixture was then stirred at 250°C for a while to remove most of the NMP.

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

[0107] The resulting cake and 90 liters of deionized water were placed in an autoclave equipped with a stirrer, and acetic acid was added to bring the pH to 7. After purging the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes. The autoclave was then cooled and the contents were removed.

[0108] The contents were filtered by suction using a glass filter, and then 76 liters of ion-exchanged water at 70°C were poured in and filtered by suction to obtain the cake. The obtained cake was dried under a nitrogen stream at 120°C to obtain dried PPS-4. The obtained PPS-5 had an ER of 90 g / 10 min, which, when converted to MFR, was 6257 g / 10 min.

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

[0110] [Method for forming a plating layer] A plating layer was formed on the molded product using the following method, and its properties were measured.

[0111] (Surface treatment process, method 1) The molded product is irradiated with ultraviolet light having wavelengths of 184.9 nm and 253.7 nm as the main wavelengths from a height of 30 mm above its surface for 60 minutes, and then immersed in a 20% by mass potassium hydroxide aqueous solution at 60°C for 5 minutes.

[0112] (Surface treatment process, method 2) The molded product is immersed in a mixed solution of 67.5% by 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 sodium hydroxide aqueous solution.

[0113] (Catalyst application process ~ Plating process) The surface of the molded product with a roughened surface obtained in the surface treatment step was adjusted by immersing it in CC-231 (Rhom and Hass) adjusted to 10% by volume at 45°C for 2 minutes, and 0.3 g / dm 3 aqueous solution of palladium dichloride was used as a catalyst solution and applied to the surface of the roughened molded product by immersing it at 45°C for 2 minutes. Then, it was immersed in an aqueous solution of sodium phosphinate at 19 g / dm 3 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, chemical copper plating was performed on the molded product with palladium metal deposited on the surface obtained in the above step, and then electroplating was further performed to perform bright nickel plating.

[0115] The raw materials used in the present invention are shown 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, glycidyl group concentration 3.63% by weight) C-2: Epoxy group-containing polyolefin (Bondfast 7M manufactured by Mitsui Chemicals, glycidyl group concentration 1.81% by weight) C-3: Epoxy group-containing polyolefin (SK Chemical Polymer, LOTADER AX8750, glycidyl group concentration 1.51% by weight) C-4: Hydrogenated styrene-based thermoplastic elastomer (Asahi Kasei Corporation, ToughTec MP10, reactive functional group: amide group) C-5: Hydrogenated styrene-based thermoplastic elastomer (Asahi Kasei Co., Ltd., ToughTec M1913, 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 (Sankyo Seifun Co., Ltd. #800) D-3: Heavy calcium carbonate (Super S, manufactured by Maruo Calcium Co., Ltd.) D-4: Magnesium hydroxide (Kisma 5P, manufactured by Kyowa Chemical Industry Co., Ltd.) (E) Olefin copolymer that does not contain functional groups E-1: Olefin copolymer (Engage8842, manufactured by The Dow Chemical Company) Molded articles and plated molded articles made from resin compositions were evaluated using the measurement methods described below.

[0117] (1) Size of pore diameter The surface of the molded product after the surface treatment process was observed using a scanning electron microscope (JSM-IT100) manufactured by JEOL Ltd. Secondary electron images were observed at a magnification of 5000x, 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 surface roughness of plated molded products was measured using a Mitutoyo SV-2100 surface roughness measuring instrument in accordance with JIS-B-0601, and the arithmetic mean roughness Ra was determined. Products where no plating layer was formed, or where the plating layer was formed but lifted, making surface roughness measurement difficult, were marked with "-".

[0119] (3) Tensile strength The tensile strength of molded articles made from resin compositions was measured in accordance with ISO 527-1, 2 (2012). Specifically, the measurement was performed as follows: Pellets of polyphenylene sulfide resin composition were dried at 130°C for 3 hours using a hot air dryer, and then supplied to a Sumitomo Heavy Industries, Ltd. injection molding machine (SE-50D) set to cylinder temperature: 310°C and mold temperature: 145°C. Using a mold of type A1 test specimen shape (4 mm thickness) as specified in ISO 20753 (2008), injection molding was performed under conditions where the average speed of molten resin passing through the cross-sectional area of ​​the central parallel section was 400 ± 50 mm / s to obtain test specimens. After conditioning the specimen at 23°C and 50% relative humidity for 16 hours, the tensile strength was measured in accordance with ISO 527-1, -2 (2012) under the conditions of 23°C and 50% relative humidity, with a grip distance of 115 mm and a test speed of 5 mm / min. A higher value indicates superior mechanical strength, and is preferable, with a value of 160 MPa or higher being desirable from the standpoint of versatility.

[0120] (4) Peel strength The peel strength of the plating layer on plated molded products was evaluated using the following procedure. First, the polyphenylene sulfide resin composition pellets obtained in the examples and comparative examples were dried at 130°C for 3 hours using a hot air dryer. Then, they were supplied to a Sumitomo Heavy Industries, Ltd. injection molding machine (SE-50D) set to a cylinder temperature of 310°C and a mold temperature of 145°C. A test piece with a side length of 80 mm and a thickness of 3 mm, as shown in Figure 1, was molded at an injection speed of 100 mm / s. From this, strip test pieces with a width of 15 mm, a length of 80 mm, and a thickness of 3 mm were cut out. A plating layer was formed on the molded product using the following method on the cut strip test pieces.

[0121] A compact ultraviolet irradiation device (KOL1-300S, manufactured by Koto Electric Co., Ltd.) equipped with one high-power low-pressure mercury lamp (300W) having the main wavelengths of 184.9 nm and 253.7 nm was used to irradiate the test specimen surface with ultraviolet light having the main wavelengths of 184.9 nm and 253.7 nm from a height of 30 mm for 60 minutes. After that, the specimen was immersed in a 20 wt% potassium hydroxide aqueous solution for 12 minutes to perform the surface treatment process.

[0122] Next, 0.3 g / dm³ is added to the roughened molded product obtained in the above step. 3 A palladium dichloride aqueous solution was used as the catalyst solution, and this catalyst solution was applied to the roughened surface of the molded product at a rate of 20 g / dm 3 By using an aqueous sodium phosphinate solution, palladium dichloride on the surface of the PPS resin was reduced to metal, thereby forming a metal nucleus that facilitates the 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 product on which metallic palladium, obtained in the previous step, was deposited on the surface.

[0124] The adhesion strength of the plating layer on the obtained plated molded products was measured according to the adhesion strength test method in Annex 1 (Normative) of JIS H8630:2006. * indicates no plating was formed; D indicates a peel strength of less than 1 N / cm; C indicates a peel strength of 1 N / cm or more but less than 3 N / cm; B indicates a peel strength of 3 N / cm or more but less than 10 N / cm; and A indicates a peel strength of 10 N / cm or more.

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

[0126] A comparison of Example 1 with Examples 3-7 revealed that the plating properties were further improved by adding a functional group-containing olefin copolymer. 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 from Examples 12 and 13 showed that when a large amount of non-fibrous inorganic filler is added, the pore size after the surface treatment process tends to increase, and the adhesion of the plating layer tends to decrease.

[0129] Furthermore, the results from Comparative Examples 4-6 showed that a plating layer is not formed when the pore diameter is large.

[0130] [Table 1]

[0131] [Table 2] [Industrial applicability]

[0132] The present invention provides a polyphenylene sulfide resin composition for plating and a resin-plated molded product that enables the formation of a plating layer with excellent surface smoothness without sacrificing the excellent properties inherent in polyphenylene sulfide resin, and that ensures high plating quality even in harsh environmental degradation tests such as thermal shock cycle tests, while also exhibiting excellent adhesion. [Explanation of symbols]

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

Claims

1. A plated molded article having a plating layer formed on part or all of the surface of a molded article which is molded from a polyphenylene sulfide resin composition containing (A) 100 parts by weight of polyphenylene sulfide resin and (B) 30 to 200 parts by weight of fibrous filler, and which has been surface-treated, wherein the (A) polyphenylene sulfide resin contains 20% by weight or more of (A-1) polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315 degrees Celsius and a load of 2160 g, when the total amount of (A) polyphenylene sulfide resin is 100% by weight, and the surface of the surface-treated molded article has pores with a diameter of 0.01 to 2 μm when observed with a scanning electron microscope, and the arithmetic mean roughness of the plating layer surface of the plated molded article is 0.5 μm or less.

2. The plated molded article according to claim 1, characterized in that the polyphenylene sulfide resin composition further comprises (A) 100 parts by weight of polyphenylene sulfide resin, and (C) 1 to 30 parts by weight of 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 salts, and an alkoxycarbonyl group.

3. The plated molded article according to claim 1 or 2, characterized in that the (A) polyphenylene sulfide resin contains 50% by weight or more of (A-1) polyphenylene sulfide resin having an MFR of 50 to 600 g / 10 min at 315 degrees Celsius and a load of 2160 g, when the total amount of (A) polyphenylene sulfide resin is 100% by weight.

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

5. A method for manufacturing a plated molded article according to any one of claims 1 to 4, characterized in that a surface treatment step, a catalyst application step, an activation treatment step, and a plating treatment step are performed in this order on a molded article formed with the polyphenylene sulfide resin composition, wherein at least a portion of the surface of the molded article after the surface treatment step has pores with a diameter of 0.01 to 2 μm.

6. The method for manufacturing a plated molded product according to claim 5, characterized in that the surface treatment step is carried out in the following procedure. (a) Irradiate the molded product with ultraviolet light having a primary wavelength of 100 to 400 nm from a position 5 to 200 mm away from the surface of the molded product for 10 to 120 minutes. (b) Then, immerse the molded product treated in (a) in an alkaline aqueous solution with a concentration of 5 to 40% by mass for 1 to 30 minutes.

7. A housing component comprising a plated molded product as described in any one of claims 1 to 4 as part of its components.

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