JP2022114252A - Polyarylene sulfide resin composition and method for producing the same - Google Patents

Abstract

To provide a resin composition having excellent electromagnetic-wave blocking properties while maintaining high strength.SOLUTION: A resin composition contains (A) a polyarylene sulfide resin, obtained by a process of directly heating and polymerizing a diiodo aryl compound, solid sulfur and a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent (A component). Relative to 100 pts.wt. of the A component, the resin composition also contains (B) metal-coated carbon fibers (B component) 5-100 pts.wt. and (C) modified ultrahigh-molecular-weight polyethylenes (C component) 1-50 pts.wt..SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a resin composition comprising a polyarylene sulfide resin, a metal-coated carbon fiber, and a modified ultra-high molecular weight polyethylene, and having excellent electromagnetic wave shielding properties while maintaining excellent mechanical strength.

Polyarylene sulfide resins are engineering plastics that are excellent in chemical resistance, heat resistance, mechanical properties, and the like. For this reason, polyarylene sulfide resins are widely used in applications such as electrics and electronics, vehicles, aircraft, and housing equipment as metal substitute materials by taking advantage of their excellent properties.

2. Description of the Related Art In recent years, as electronic devices have become smaller and lighter, and circuits have become more highly integrated and denser, it has become a problem that electronic devices may malfunction due to electromagnetic waves. Therefore, it is demanded that the housing of the electronic device has an electromagnetic wave shielding effect for shielding electromagnetic waves from the outside and an electromagnetic wave shielding effect for preventing the electromagnetic waves from leaking to the outside. In order to obtain an electromagnetic wave shielding effect, an electronic device housing must have electrical conductivity, and generally, the higher the electrical conductivity, the better the electromagnetic wave shielding properties. Conventionally, metal has been used for such housings, but attempts have been made to use plastics such as polyarylene sulfide resins from the viewpoint of workability and weight reduction. However, since plastic generally does not have conductivity like metal, it is necessary to impart conductivity to counter electromagnetic interference waves and electromagnetic noise. Typical examples of methods for imparting electromagnetic wave shielding properties to plastics include conductive surface treatments such as plating, and methods for incorporating metal powder, metal fibers, carbon fibers, metal-coated carbon fibers, and the like. As an attempt to further improve the electromagnetic wave shielding properties of plastics, for example, Patent Document 1 discloses a thermoplastic resin containing conductive fibers and an olefinic wax or olefinic polymer having a carboxylic anhydride group and/or a carboxyl group. In Patent Document 2, the O1S/C1S measured by the ESCA method on the carbon fiber surface before the nickel metal coating treatment of the nickel metal-coated carbon fiber is adjusted to a specific range. A thermoplastic resin composition containing nickel metal-coated carbon fibers obtained by the above method has been proposed. However, the method was not useful for polyarylene sulfide resins, and the electromagnetic wave shielding properties were not sufficient. Moreover, Patent Document 3 proposes a resin composition comprising a polyarylene sulfide resin, a modified polyolefin composition, and a fibrous filler, but does not describe electromagnetic wave shielding properties.

Japanese Patent No. 2732986 Japanese Patent No. 4674066 JP 2019-218568 A

An object of the present invention is to provide a resin composition having excellent electromagnetic shielding properties while maintaining excellent mechanical strength.

As a result of extensive studies, the present inventors have found that a polyarylene sulfide obtained by a method of directly heating a diiodoaryl compound, solid sulfur, a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent for polymerization. The inventors have found that a resin composition containing a resin, metal-coated carbon fiber and modified ultra-high molecular weight polyethylene is a resin composition that maintains excellent mechanical strength and is excellent in electromagnetic wave shielding properties, leading to the present invention.

Specifically, the above problem is (A) a polyarylene obtained by a method of directly heating and polymerizing a diiodoaryl compound, solid sulfur, a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent. Resin containing (B) 5 to 100 parts by weight of metal-coated carbon fiber (B component) and (C) 1 to 50 parts by weight of modified ultra-high molecular weight polyethylene (C component) with respect to 100 parts by weight of sulfide resin (A component) achieved by the composition.

The details of the present invention will be described below.

(A component: polyarylene sulfide resin)
The polyarylene sulfide resin used as the A component of the present invention is obtained by a method of directly heating and polymerizing a diiodoaryl compound, solid sulfur, a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent. It is a polyarylene sulfide resin that is used.

Examples of polyarylene sulfide resins include p-phenylene sulfide units, m-phenylene sulfide units, o-phenylene sulfide units, phenylene sulfide sulfone units, phenylene sulfide ketone units, phenylene sulfide ether units, and diphenylene sulfide units. , substituent-containing phenylene sulfide units, branched structure-containing phenylene sulfide units, etc. Among them, those containing 70 mol% or more, particularly 90 mol% or more of p-phenylene sulfide units Preferred, and more preferred is poly(p-phenylene sulfide).

The polyarylene sulfide resin used as the A component of the present invention preferably has a dispersity (Mw/Mn) represented by a weight average molecular weight (Mw) and a number average molecular weight (Mn) of 2.7 or more, more preferably 2. 0.8 or more, more preferably 2.9 or more. If the degree of dispersion is less than 2.7, burrs may occur more frequently during molding. Although the upper limit of the degree of dispersion (Mw/Mn) is not particularly defined, it is preferably 10 or less. Here, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values calculated in terms of polystyrene by gel permeation chromatography (GPC). 1-Chloronaphthalene was used as a solvent, and the column temperature was 210°C.

As a method for producing a polyarylene sulfide resin, for example, the production described in US Patent Nos. 4,746,758, 4,786,713, JP 2013-522385, JP 2012-233210 and JP 5167276, etc. method.

The manufacturing method includes an iodination step and a polymerization step. In the iodination step, an aryl compound is reacted with iodine to give a diiodoaryl compound. In the subsequent polymerization step, the diiodoaryl compound is polymerized with solid sulfur using a polymerization terminator to prepare a polyarylene sulfide resin. Iodine is generated in gaseous form in this process, and this is recovered and used again in the iodination process. Iodine is essentially a catalyst.

A representative solid sulfur used in the method of preparation includes the cyclooctasulphur form (S ₈ ) with 8 atoms linked at room temperature. However, the sulfur compound used in the polymerization reaction is not limited and may be used in any form as long as it is solid or liquid at room temperature.

Typical diiodoaryl compounds used in the production method include at least one selected from the group consisting of diiodobenzene, diiodonaphthalene, diiodobiphenyl, diiodobisphenol and diiodobenzophenone, and alkyl Derivatives of iodoaryl compounds to which a group or sulfone group is attached, or to which oxygen or nitrogen is introduced are also used. Iodoaryl compounds are classified into different isomers depending on the bonding position of the iodine atom, and preferred examples of these isomers are p-diiodobenzene, 2,6-diiodonaphthalene, and p,p'-diiodine. It is a compound in which iodine is symmetrically positioned at both ends of an aryl compound, such as biphenyl. The content of the iodoaryl compound is preferably 500 to 10,000 parts by weight with respect to 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

Typical polymerization terminator used in the production method includes diphenyl sulfide and diphenyl disulfide. The content of the polymerization terminator is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

A polymerization reaction catalyst may be used in the production method, and a typical polymerization reaction catalyst is a nitrobenzene-based catalyst. Preferred examples of nitrobenzene-based catalysts include 1,3-diiodo-4-nitrobenzene, 1-iodo-4-nitrobenzene, 2,6-diiodo-4-nitrophenol, iodonitrobenzene, 2,6-diiodo-4- At least one selected from the group consisting of nitroamines can be mentioned. The content of the polymerization reaction catalyst is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

By using the polyarylene sulfide resin prepared by this polymerization method, the addition of modified ultra-high molecular weight polyethylene reduces the adhesion between the polyarylene sulfide resin and the metal-coated carbon fiber, and the metal coating during melt kneading. It is thought that the breakage of the carbon fibers can be suppressed and the electromagnetic wave shielding properties are improved.

(B component: metal-coated carbon fiber)
The metal-coated carbon fiber used in the present invention is obtained by coating a carbon fiber with a metal by a known method such as a plating method and a vapor deposition method. A coated one is preferred. When carbon fibers that are not coated with metal are used, the electromagnetic wave shielding properties are poor. Furthermore, in the metal-coated carbon fiber of the present invention, it is preferable to provide a metal coating on the surface of the carbon fiber by electroplating. Electroplating forms a stronger metal coating and provides a resin composition having good electromagnetic wave shielding properties.

Examples of carbon fibers to be metal-coated include carbon fibers starting from polymer fibers such as phenolic resin, rayon, and polyacrylonitrile, and pitch-based fibers such as coal-based pitch, petroleum-based pitch, and liquid crystal pitch. Carbon fiber as a raw material is typically exemplified. Alternatively, a method of spinning or molding a raw material composition comprising a polymer with a methylene bond of an aromatic sulfonic acid or a salt thereof and a solvent, followed by carbonization, in which spinning is performed without undergoing an infusibilization step. It is also possible to use carbon fibers obtained by Furthermore, general-purpose type, medium modulus type, and high modulus type can all be used.

In the carbonization or graphitization of carbon fibers, it is preferable to calcine fibers that can be converted into carbon fibers at a temperature of, for example, about 450 to 1,500°C. It is preferable to carry out the firing treatment at a temperature of about 500 to 3,300°C. It should be noted that such heat treatment does not necessarily require the formation of a graphite crystal structure.

The content of component B is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, more preferably 20 to 60 parts by weight, per 100 parts by weight of component A. If the content of component B is less than 5 parts by weight, sufficient mechanical strength cannot be obtained and the electromagnetic wave shielding properties are also inferior. On the other hand, if it exceeds 100 parts by weight, the productivity or moldability will be lowered.

(C component: modified ultra-high molecular weight polyethylene)
The modified ultra-high molecular weight polyethylene used in the present invention is a polymer obtained by modifying ultra-high molecular weight polyethylene. Modified ultra-high molecular weight polyethylene can be obtained, for example, by melt-kneading ultra-high molecular weight polyethylene and a compound containing a modifying group, and graft-modifying the ultra-high molecular weight polyethylene to introduce modifying groups. The modified polyethylene may be a mixture of polyethylene and ultra high molecular weight polyethylene. Examples of modifying components used for modification include maleic anhydride and itaconic anhydride, with maleic anhydride being particularly preferred. The content of the modifying group in component C is preferably 0.05 to 3% by weight. If it is less than 0.05% by weight, the electromagnetic wave shielding properties may be inferior, and if it exceeds 3% by weight, the mechanical properties may be inferior. Such modified polyethylene is readily available from Mitsui Chemicals, Inc. as Lubmer LY1040. When non-modified ultra-high molecular weight polyethylene is used, the electromagnetic wave shielding property is inferior. Also, the weight average molecular weight of the modified ultra-high molecular weight polyethylene is preferably less than 6,000,000, more preferably less than 3,000,000, even more preferably less than 1,000,000. In addition, the lower limit of the weight average molecular weight is preferably 100,000 or more, more preferably 150,000 or more. If the weight-average molecular weight is 6,000,000 or more, the productivity or workability may be poor, and if it is less than 100,000, the electromagnetic shielding property may be poor.

The content of component C is 1 to 50 parts by weight, preferably 2 to 40 parts by weight, more preferably 3 to 30 parts by weight, per 100 parts by weight of component A. If the content is less than 1 part by weight, the electromagnetic wave shielding properties are insufficient, and if it exceeds 50 parts by weight, the mechanical properties are remarkably lowered.

(other ingredients)
Inorganic fillers other than metal-coated carbon fibers can be used in combination with the resin composition of the present invention as long as the effects of the present invention are not impaired. Examples of inorganic fillers include fibrous fillers other than metal-coated carbon fibers, powder fillers, and plate-like fillers. Examples of fibrous fillers include glass fibers, aramid fibers, potassium titanate whiskers, zinc oxide whiskers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, metal fibers, and non-metallic conductive substances. and inorganic fibers. SnO ₂ (antimony-doped), In ₂ O ₃ (antimony-doped), etc. can be given as specific examples of the conductive substance in the inorganic fiber coated with a conductive substance other than metal. Inorganic fibers to be coated include glass fibers, potassium titanate whiskers, zinc oxide whiskers, titanate whiskers, silicon carbide whiskers, and the like. Examples of coating methods include a vacuum deposition method, a sputtering method, an electroless plating method, and a baking method. Moreover, these may be surface-treated with a surface treatment agent such as a titanate-based, aluminum-based, or silane-based coupling agent. In addition, pretreatment of these fibrous fillers with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound and an epoxy compound leads to better mechanical strength. is preferable in the sense of obtaining Examples of powdery fillers include carbon black, calcium carbonate, silica, titanium oxide, graphite, carbon nanotubes, and metal powders. Examples of plate-like fillers include talc and mica.

The resin composition in the present invention can contain an elastomer component within a range that does not impair the effects of the present invention. Suitable elastomer components include acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-butadiene-styrene copolymer (MBS resin), and core-shell such as silicone-acrylic composite rubber graft copolymer. Examples include graft copolymer resins, thermoplastic elastomers such as silicone thermoplastic elastomers, olefin thermoplastic elastomers, polyamide thermoplastic elastomers, polyester thermoplastic elastomers, and polyurethane thermoplastic elastomers.

The resin composition in the present invention can contain other thermoplastic resins as long as the effects of the present invention are not impaired. Other thermoplastic resins include, for example, polyethylene resins, polypropylene resins, general-purpose plastics represented by polyalkyl methacrylate resins, polyphenylene ether resins, polyacetal resins, aromatic polyester resins, liquid crystalline polyester resins, polyamide resins, cyclic Engineering plastics represented by polyolefin resin, polyarylate resin (amorphous polyarylate, liquid crystalline polyarylate), polytetrafluoroethylene, polyetheretherketone, polyetherimide, polysulfone, polyethersulfone, etc. So-called super engineering plastics can be mentioned.

The resin composition of the present invention contains antioxidants, heat stabilizers (hindered phenols, hydroquinones, phosphites, and substituted compounds thereof), weathering agents (resorcinols, salicylates, benzotriazoles, benzophenones, hindered amines, etc.), release agents and lubricants (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide, various bisamides, bisurea and polyethylene waxes, etc.) , pigments (cadmium sulfide, phthalocyanine, carbon black, etc.), dyes (nigrosine, etc.), crystal nucleating agents (talc, silica, kaolin, clay, etc.), plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.) ), antistatic agents (alkyl sulfate type anionic antistatic agents, quaternary ammonium salt type cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine amphoteric antistatic agents, etc. ), flame retardants (red phosphorus, phosphates, melamine cyanurate, magnesium hydroxide, hydroxides such as aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resin Alternatively, combinations of these brominated flame retardants with antimony trioxide, etc.) and other polymers can be added.

(Manufacture of resin composition)
The resin composition of the present invention can be produced by mixing the above components at the same time or in any order using a mixer such as a tumbler, V-type blender, Nauta mixer, Banbury mixer, kneading rolls, and extruder. Melt-kneading by a twin-screw extruder is preferable, and if necessary, it is preferable to feed optional components into other melt-mixed components from the second supply port using a side feeder or the like.

The resin extruded as described above is either directly cut and pelletized, or is pelletized by forming strands and then cutting the strands with a pelletizer. It is preferable to clean the atmosphere around the extruder when it is necessary to reduce the influence of external dust during pelletization. The shape of the obtained pellets can take general shapes such as cylinders, prisms, and spheres, but cylinders are more preferable. The diameter of such a cylinder is preferably 1-5 mm, more preferably 1.5-4 mm, still more preferably 2-3.5 mm. On the other hand, the length of the cylinder is preferably 1-30 mm, more preferably 2-5 mm, and even more preferably 2.5-4 mm.

(About molded products)
A molded article using the resin composition of the present invention can be obtained by molding the pellets produced as described above. It is preferably obtained by injection molding or extrusion molding. In injection molding, not only ordinary molding methods, but also injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including the method of injecting supercritical fluid), insert molding, in-mold coating molding, heat insulation Mold molding, rapid heating and cooling mold molding, two-color molding, multi-color molding, sandwich molding, ultra-high speed injection molding and the like can be mentioned. For molding, either cold runner method or hot runner method can be selected. Extrusion molding can also provide various shaped extruded products, sheets, films, and the like. Inflation method, calendering method, casting method and the like can be used for forming sheets and films. Further, it can be molded as a heat-shrinkable tube by subjecting it to a specific stretching operation. The resin composition of the present invention can also be molded by rotational molding, blow molding, or the like.

Further, various surface treatments can be applied to the molded articles produced by the various methods described above. Surface treatment here refers to deposition (physical vapor deposition, chemical vapor deposition, etc.), plating (electroplating, electroless plating, hot dipping, etc.), painting, coating, printing, etc. Various methods used for resin molded products can be applied. Furthermore, by subjecting the sheet molded product (including the ribbon-shaped molded product) to various vacuum forming, hot press forming, bending, etc., various transport containers, electromagnetic wave shielding covers, and the like can be produced.

The resin composition of the present invention is excellent in electromagnetic wave shielding properties while maintaining excellent mechanical strength. Therefore, molded articles obtained from the resin composition of the present invention are suitably used as covers for electronic devices, antennas, and the like.

The best mode of the present invention, which the present inventors consider to be the best, summarizes the preferable range of each of the requirements described above, and representative examples thereof are described in the following examples, for example. Of course, the present invention is not limited to these forms.

[Evaluation of Resin Composition]
(1) Tensile strength at break Measured according to ISO527 (measurement conditions: 23°C). In addition, the test piece was molded by the following method. It means that the larger the numerical value, the better the mechanical strength of the resin composition.

(2) Electromagnetic wave shielding property Using a test piece of 150 x 150 x 2 mmt, electromagnetic wave shielding property was measured with respect to an electric field wave (frequency of 500 MHz) with a network analyzer (manufactured by Keysight Technologies) and a KEC method measuring device (manufactured by JSE). . It means that the larger the numerical value, the better the electromagnetic wave shielding property.

[Examples 1 to 6, Comparative Examples 1 to 8]
Polyarylene sulfide resin, metal-coated carbon fiber, and modified ultra-high molecular weight polyethylene were melt-kneaded in the amounts shown in Table 1 using a vented twin-screw extruder to obtain pellets. The vented twin-screw extruder used was TEX30α-38 (completely meshed, co-rotating) manufactured by Japan Steel Works, Ltd. The extrusion conditions were a discharge rate of 20 kg/h, a screw rotation speed of 200 rpm, and a vent vacuum degree of 3 kPa. The metal-coated carbon fiber was supplied from the second supply port using the side feeder of the extruder, and the polyarylene sulfide resin and the modified ultrahigh molecular weight polyethylene were supplied to the extruder from the first supply port. The first feed port here is the feed port farthest from the die, and the second feed port is the feed port located between the die and the first feed port of the extruder. After drying the obtained pellets at 130 ° C. for 6 hours with a hot air circulating dryer, an injection molding machine (EC160NII-4Y manufactured by Toshiba Machine Co., Ltd.) was used for evaluation at a cylinder temperature of 320 ° C. and a mold temperature of 140 ° C. A test piece was molded.

Each component of symbol notation in Table 1 is as follows.
<A component>
A-1: Polyphenylene sulfide resin obtained by the following production method [manufacturing method]
To 300.00 g of paradiiodobenzene and 27.00 g of sulfur, 0.60 g of diphenyl disulfide as a polymerization terminator (content of 0.65% by weight based on the weight of the final polymerized PPS) was added and heated to 180°C. After heating to completely melt and mix them, the temperature was raised to 220°C and the pressure was lowered to 200 Torr. The obtained mixture is polymerized for 8 hours while changing the temperature and pressure stepwise so that the final temperature and pressure are 320° C. and 1 Torr, respectively, to obtain a polyphenylene sulfide resin (A- 1) was obtained.

A-2: Polyphenylene sulfide resin obtained by the following production method [manufacturing method]
1814 g of flaky sodium sulfide (Na ₂ S.2.9H ₂ O), 8.7 g of granular caustic soda (100% NaOH: special grade of Wako Pure Chemical) and N-methyl-2-pyrrolidone were placed in a 15-liter autoclave equipped with a stirrer. 3232 g was charged, and the temperature was gradually raised to 200° C. while stirring under a nitrogen stream, and 339 g of water was distilled off. After cooling to 190° C., 2129 g of p-dichlorobenzene and 1783 g of N-methyl-2-pyrrolidone were added, and the system was sealed under nitrogen stream. The system was heated to 225° C. over 2 hours, polymerized at 225° C. for 1 hour, then heated to 250° C. over 25 minutes, and polymerized at 250° C. for 2 hours. Then, 509 g of distilled water was injected into this system at 250° C., the temperature was raised to 255° C., and the polymerization reaction was further carried out for 2 hours. After the polymerization was completed, the system was cooled to room temperature, and the polymer slurry was subjected to solid-liquid separation using a centrifugal filter. The cake was washed successively three times with N-methyl-2-pyrrolidone and acetone under a nitrogen stream, and further washed successively with 0.2% hydrochloric acid and warm water under a nitrogen stream. The resulting poly(p-phenylene sulfide) was dried at 105° C. for one day to obtain a polyarylene sulfide resin (A-2).

<B component>
B-1: HT C923 (manufactured by Teijin Limited, fiber diameter: 7.5 μm, cut length: 6 mm, nickel metal coated carbon fiber)
B-2: Copper metal-coated carbon fiber (fiber diameter: 7.5 μm, cut length: 6 mm, copper metal-coated carbon fiber) plated with copper according to the conditions disclosed in JP-A-59-226195.
B-3: HT P722 (manufactured by Teijin Limited, fiber system: 7.0 μm, cut length: 3 mm, PAN-based carbon fiber)

<C component>
C-1: LY1040 (Lubmer (trade name) manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified ultra-high molecular weight polyethylene, weight average molecular weight 160,000)
C-2: Hi-Zex 2200J (manufactured by Prime Polymer Co., Ltd., polyethylene, weight average molecular weight less than 100,000)
C-3: Hi-Zex Million 630M (Ultra-high molecular weight polyethylene manufactured by Mitsui Chemicals, Inc., weight average molecular weight of 100,000 or more)

Claims (4)

(A) 100 parts by weight of a polyarylene sulfide resin (Component A) obtained by directly heating and polymerizing a diiodoaryl compound, solid sulfur, a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent. On the other hand, (B) 5 to 100 parts by weight of metal-coated carbon fiber (component B) and (C) a resin composition containing 1 to 50 parts by weight of modified ultra-high molecular weight polyethylene (component C). 2. The resin composition according to claim 1, wherein the terminal group of component A is a phenyl group. 3. The resin composition according to claim 1, wherein the C component is a modified ultra-high molecular weight polyethylene modified with maleic anhydride. (A) 100 parts by weight of a polyarylene sulfide resin (Component A) obtained by directly heating and polymerizing a diiodoaryl compound, solid sulfur, a polymerization terminator and/or a polymerization reaction catalyst without using a polar solvent. (B) metal-coated carbon fiber (component B) 5 to 100 parts by weight and (C) modified ultra-high molecular weight polyethylene (component C) 1 to 50 parts by weight.