JP2012238764A - Composite resin composition and molding exhibiting excellent electromagnetic wave shielding properties - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite resin composition having moldability and lightweight properties superior to those of metal materials, and having electromagnetic wave shielding properties and mechanical strength superior to those of resin materials.SOLUTION: The composite resin composition contains (A) electromagnetic wave shielding fibers and (B) a resin as constitutive materials. In a molding obtained by molding the resin composition, electrical field shielding properties at 800 MHz measured by KEC method is 20 dB or more, the flexural strength measured in compliance with JIS K 6911 is 80 MPa or higher, the flexural modulus is 8 GPa or higher, the specific gravity measured in compliance with JIS K 6911 is 1-5, and the linear expansion coefficient in the plane direction is 0.1-50 ppm/°C. A molding using the composite resin composition and having excellent electromagnetic wave shielding properties is also provided.

Description

  The present invention relates to a composite resin composition and a molded article excellent in electromagnetic wave shielding properties.

  There is a concern that electromagnetic waves generated from electronic devices may adversely affect the environment of other electronic devices and human bodies, and in recent years, interest in electromagnetic waves has increased. In order to reduce electromagnetic waves, efforts are being made to cover electronic devices with a conductive housing or the like.

  As a case having conductivity, methods such as plating a metal or resin case, attaching a metal foil, covering with a metal non-woven fabric, woven fabric, or plate have been proposed. However, metal materials are excellent in shielding electromagnetic waves, but their specific gravity is large, which causes an increase in product weight, making them difficult to fabricate and having complicated shapes as compared with resin materials.

  In addition, since the surface metal coat by a technique such as electroless plating of resin follows a complicated shape, electromagnetic waves can be shielded while taking advantage of the lightness of the resin. However, taking electroless plating as an example, the process is complicated and requires many steps such as degreasing, etching, catalysis, activation, electroless plating, and electroplating, and the amount of chemical used is large. In many cases, there is room for improvement in terms of increasing production costs, such as the need to deal with environmental loads such as plating solution treatment.

  In addition, it is difficult to follow a complicated shape for a method of attaching a metal foil, a metal nonwoven fabric, a woven fabric, a plate, etc. to a resin casing, and the surface or inner surface must be covered without a gap. There were also problems such as not becoming necessary, and there was room for improvement in that a precise sticking process was required, leading to an increase in cost. For this reason, studies have been made to produce an electromagnetic wave shielding sheet in which an internal space of a nonwoven fabric made of metal fibers is filled with a thermoplastic resin and the metal fibers have flexibility and flexibility (see, for example, Patent Document 1). .

  In addition, metal powder and metal fibers are mixed with resin to try to develop electromagnetic shielding properties. However, because the specific gravity of the resin and metal is different, they cannot be kneaded well and segregate within the material. In order to solve the problem, metal fibers are broken due to mechanical shearing force. In order to solve the problem, conductive fibers are injection-molded together with a flexible thermoplastic resin. A method has been proposed in which the electromagnetic wave shielding performance is exhibited without being damaged (for example, Patent Document 2).

JP 2000-091786 A JP 2006-278574 A

  However, in the method described in Patent Document 1, an electromagnetic wave shielding material excellent in flexibility and flexibility is proposed by preparing a non-woven fabric with metal fibers in advance and filling the gap with a thermoplastic resin. Since the material is produced using a non-woven fabric as a pillar, the ratio of metal increases, which causes an increase in the weight of the product. Moreover, since it is necessary to produce the shape of a metal nonwoven fabric, the subject remained in the point that adjustment of the ratio of a metal fiber and resin was difficult.

  Further, in the method described in Patent Document 2, since a metal fiber is not cut by a mechanical shearing force, it is essential to use a flexible thermoplastic resin, the heat resistance of the molding material itself is lowered, the rigidity is low, etc. For the reason, the subject that it was difficult to use depending on the use was left.

  An object of the present invention is to provide a composite resin composition that is superior in molding processability and light weight to a metal material, and excellent in electromagnetic wave shielding properties and mechanical strength than a resin material.

The above object is achieved by the following items (1) to (18).
(1) As a constituent material, a composite resin composition containing (A) an electromagnetic wave shielding fiber and (B) a resin, and 800 MHz measured by the KEC method in a molded product obtained by molding the resin composition The electric field wave shielding property is 20 dB or more, the bending strength measured in accordance with JIS K 6911 is 80 MPa or more, the bending elastic modulus is 8 GPa or more, and the specific gravity measured in accordance with JIS K 6911 is 1 to 5 A linear resin has a linear expansion coefficient of 0.1 ppm / ° C. or more and 50 ppm / ° C. or less.

(2) The composite resin composition according to item (1), wherein the average fiber length of the electromagnetic shielding fiber (A) is 500 μm or more and 10 mm or less.

(3) The content of the electromagnetic shielding fiber (A) is 1% by mass or more and 90% by mass or less of the entire composite resin composition, according to item (1) or item (2), Composite resin composition.

(4) The composite resin composition according to any one of (1) to (3), wherein the electromagnetic shielding fiber (A) includes a metal fiber.

(5) The composite resin composition as described in (4), wherein the metal element constituting the metal fiber contains at least one metal element selected from iron, silver, nickel, aluminum and copper.

(6) The composite according to any one of (1) to (5), wherein the constituent material further includes (C) a fiber other than the (A) electromagnetic wave shielding fiber. Resin composition.

(7) The fiber of the component (C) other than the (A) electromagnetic shielding fiber is a natural fiber such as wood fiber, cotton, hemp, or wool, a regenerated fiber such as rayon fiber, a semi-synthetic fiber such as cellulose fiber, Synthetic fibers such as polyamide fiber, aramid fiber, polyimide fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber polyparaphenylene benzoxazole fiber, polyethylene fiber, polypropylene fiber, polyacrylonitrile fiber, ethylene vinyl alcohol fiber, glass fiber, ceramic The composite resin composition according to item (6), comprising at least one fiber selected from inorganic fibers such as fibers.

(8) The composite resin composition according to any one of (1) to (7), wherein the resin (B) has an average particle size of 500 μm or less.

(9) A composite obtained by dispersing the constituent material in a solvent, adding a polymer flocculant, aggregating the constituent material in a floc form, separating the aggregate from the solvent, and then removing the solvent. The resin composition according to any one of (1) to (8), wherein the constituent material further includes (D) a powdery substance having ion exchange capacity. Composite resin composition.

(10) The powdery substance having ion exchange capacity (D) is at least one intercalation compound selected from clay minerals, scaly silica fine particles, hydrotalcites, fluorine teniolite and swellable synthetic mica. The composite resin composition according to item (9), which is characterized.

(11) The powdery substance having ion exchange capacity (D) contains at least one clay mineral selected from smectite, halloysite, kanemite, kenyaite, zirconium phosphate and titanium phosphate (9) The composite resin composition according to item.

(12) The powdery substance having ion exchange capacity (D) contains at least one smectite selected from montmorillonite, beidellite, nontronite, saponite, hectorite, soconite and stevensite. (9) Item composite resin composition.

(13) The composite resin composition as described in (9), wherein the powdery substance having ion exchange capacity (D) contains montmorillonite.

(14) The content of the powdery substance having ion exchange capacity (D) is 0.1% by mass or more and 30% by mass or less of the entire composite resin composition. The composite resin composition according to any one of items 13).

(15) The constituent material further includes (E) at least one filler powder selected from inorganic powders and metal powders. Composite resin composition.

(16) The metal element constituting the metal powder includes at least one metal element selected from aluminum, silver, copper, magnesium, iron, chromium, nickel, titanium, zinc, tin, molybdenum and tungsten. The composite resin composition according to item (15).

(17) The composite resin composition according to any one of (9) to (16), wherein the solvent has a boiling point of 50 ° C. or higher and 200 ° C. or lower.

(18) A molded article excellent in electromagnetic wave shielding property, comprising the composite resin composition according to any one of items (1) to (17).

  According to the present invention, it is possible to obtain a composite resin composition that is excellent in molding processability and light weight as compared with a metal material, and excellent in electromagnetic wave shielding properties and mechanical strength as compared with a resin material.

  The composite resin composition of the present invention is a composite resin composition containing (A) electromagnetic wave shielding fiber and (B) resin as constituent materials, and a KEC method in a molded product obtained by molding the resin composition The 800 MHz electric field shielding property measured by the above is 20 dB or more, the bending strength measured according to JIS K 6911 is 80 MPa or more, the flexural modulus is 8 GPa or more, and the specific gravity measured according to JIS K 6911 is 1 to 5 and the linear expansion coefficient in the plane direction is 0.1 ppm / ° C. to 50 ppm / ° C. By setting it as such a structure, the composite resin composition which is excellent in a moldability and lightweight property than a metal material, and is excellent in electromagnetic wave shielding property and mechanical strength than a resin material can be obtained. Hereinafter, the present invention will be described in detail.

The composite resin composition of the present invention preferably has a 800 MHz electric field shielding property measured by the KEC method of 20 dB or more, more preferably 30 dB or more, in a molded product obtained by molding the composite resin composition. What is 40 dB or more is particularly preferable. By setting it to the above lower limit or more, a molded article having excellent electromagnetic wave shielding properties can be obtained. In the present invention, the shape of the test piece for measuring the electric wave shielding property by the KEC method is not particularly limited. For example, a molded product having a length of 120 mm × width of 120 mm × thickness of 1 mm can be used. . There is no particular limitation on the method of molding a molded product for a test piece for evaluating electric wave shielding properties using a composite resin composition. For example, press molding, compression molding, calendar roll molding, SMC A molding method such as a method of injection molding, a matched die method, a metal, a resin, a woven fabric, a nonwoven fabric, or the like can be used. In this case, when a thermosetting resin is used as the constituent material (B) resin, annealing treatment is performed for about 1 to 6 hours within a range of about ± 20 ° C. with respect to the molding temperature after the curing molding. Is preferred.

  The composite resin composition of the present invention preferably has a bending strength measured in accordance with JIS K 6911 of 80 MPa or more, more preferably 120 MPa or more, in a molded product obtained by molding the composite resin composition. The above is particularly preferable. By setting it to the above lower limit or more, a molded article having excellent strength can be obtained. Moreover, the composite resin composition of the present invention preferably has a flexural modulus of 8 GPa or more measured in accordance with JIS K 6911, more preferably 10 GPa or more, in a molded product obtained by molding the composite resin composition. Preferably, it is 12 GPa or more. By setting it to the above lower limit or more, a molded article having excellent rigidity can be obtained.

  The composite resin composition of the present invention preferably has a specific gravity of 1 or more and 5 or less, more preferably 1 or more and 4 or less, in a molded product obtained by molding the composite resin composition. Those having 1 or more and 2 or less are particularly preferable. By setting it to the upper limit value or less, a molded article having excellent lightness can be obtained. In addition, when a texture is required, a material having a large specific gravity may be required. In such a case, a material having a specific gravity of 3 to 5 is preferable.

  The composite resin composition of the present invention preferably has a linear expansion coefficient in the plane direction of from 0.1 ppm / ° C. to 50 ppm / ° C., preferably from 1 ppm / ° C. to 45 ppm / ° C., in a molded product obtained by molding the composite resin composition. What is below is more preferable and what is 3 ppm / degrees C or more and 40 ppm / degrees C or less is especially preferable. By setting it to the upper limit value or less, a molded body excellent in low stress can be obtained.

  In the molded product obtained by molding the composite resin composition of the present invention, in order to make the electric field wave shielding property, bending strength, bending elastic modulus, specific gravity, and linear expansion coefficient in the plane direction within the above-described ranges, (A) Type and shape of electromagnetic shielding fiber, which is a constituent material of the composite resin composition, (B) Type and shape of resin, and (A) Mixing ratio of electromagnetic shielding fiber and (B) resin It can be adjusted by changing.

  The composite resin composition of the present invention can contain (A) an electromagnetic wave shielding fiber. (A) The average fiber length of the electromagnetic wave shielding fiber is not particularly limited, and is preferably selected as appropriate according to the required characteristics. For example, it is preferably 500 μm or more and 10 mm or less. From the viewpoint of molding processability, it is more preferably 500 μm or more and 3 mm or less, and from the viewpoint of improving characteristics such as thermal conductivity, electromagnetic wave shielding properties, and rigidity, it is particularly preferably 3 mm or more and 8 mm or less. . When the average fiber length is less than the above lower limit value, the fiber length is too short, and thus characteristics such as electromagnetic wave shielding and rigidity may be difficult to be exhibited. Further, if the average fiber length exceeds the above upper limit, it is effective for electromagnetic wave shielding, but it is not preferable because it causes a decrease in moldability. In addition, when using several electromagnetic wave shielding fiber from which average fiber length differs, it is possible to use that whose average fiber length is less than the said lower limit as a part. In this case, it is possible to improve the moldability without impairing the expression of the electromagnetic wave shielding properties by using the long fibers.

  (A) The content of the electromagnetic shielding fiber is not particularly limited, and is preferably set as appropriate according to the required request. For example, when workability or lightness of the resin is required, Preferably, the content of the composite resin composition is 1% by mass or more and less than 30% by mass. When it is required that the electromagnetic wave shielding effect and the moldability are expressed in a balanced manner, the entire composite resin composition The content is preferably 30% by mass or more and less than 60% by mass, and when a high electromagnetic shielding effect is required, the content is 60% by mass or more and 90% by mass or less of the total content of the composite resin composition. Is desirable. When the content of the composite resin composition is less than 1% by mass, the lightness and workability are improved, but the electromagnetic wave shielding effect is thin. Moreover, when it is more than 90% by mass of the total content of the composite resin composition, it becomes a material having a high electromagnetic shielding effect, but it is not preferable because the lightness and workability deteriorate.

  The component (A) electromagnetic wave shielding fiber is not particularly limited as long as it is a fiber having an effect of shielding electromagnetic waves. For example, metal fiber, carbon fiber, metal-coated organic fiber, and metal-coated carbon Examples include fibers. Among these, metal fiber is preferable from the viewpoint of electromagnetic shielding effect and low cost.

  The metal fiber may be a metal fiber composed of a single metal element or an alloy fiber composed of a plurality of metals, but examples of the metal element constituting the metal fiber include iron, Silver, nickel, aluminum, copper, etc. are mentioned.

  (A) Examples of electromagnetic shielding fibers include stainless steel fibers manufactured by Nippon Seisen Co., Ltd. and Bekaert Japan Co., Ltd., copper fibers manufactured by Niji Gi Co., Ltd., aluminum fibers, brass fibers, steel fibers, titanium fibers, phosphorus Metal fibers such as bronze fibers, carbon fibers manufactured by Toho Tenax Co., Ltd., and metal-coated carbon fibers are commercially available, but are not limited thereto. These electromagnetic wave shielding fibers may be used alone or in combination of two or more. Of these, stainless steel fibers are preferable because of high relative permeability, and copper fibers and aluminum fibers are particularly preferable because of high specific conductivity.

  (A) The electromagnetic wave shielding fiber may be used as it is, but may be surface-treated with a silane coupling agent, an aluminate coupling agent, a titanate coupling agent or the like according to necessary characteristics, You may use what performed the sizing agent process in order to improve a handleability.

  Depending on the required properties required, (C) fibers other than (A) fibers can be further included. (A) The fibers other than the fibers (C) are not particularly limited. For example, natural fibers such as wood fibers, cotton, hemp and wool, regenerated fibers such as rayon fibers, and semi-synthetic materials such as cellulose fibers. Fiber, polyamide fiber, aramid fiber, polyimide fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber, polyparaphenylene benzoxazole fiber, polyethylene fiber, polypropylene fiber, polyacrylonitrile fiber, synthetic fiber such as ethylene vinyl alcohol fiber, and glass Examples thereof include inorganic fibers such as fibers and ceramic fibers. These fibers may be used alone or in combination of two or more. Of these, polyamide fibers, aramid fibers, polyimide fibers, polyparaphenylene benzoxazole fibers and the like are preferable from the viewpoint of improving bending strength, and inorganic fibers such as glass fibers and ceramic fibers are preferable from the viewpoint of improving bending elastic modulus. preferable.

Examples of (C) fibers other than (A) fibers include, for example, Kevlar (registered trademark), which is an aramid fiber manufactured by Toray DuPont Co., Ltd., and Technora (registered trademark), which is an aramid fiber of Teijin Techno Products Co., Ltd. , Vinylon, a polyvinyl alcohol fiber manufactured by Kuraray Co., Ltd., Zylon (registered trademark), a polyparaphenylene benzoxazole fiber manufactured by Toyobo Co., Ltd., a glass fiber manufactured by Nittobo Co., Ltd., manufactured by Denki Kagaku Kogyo Co., Ltd. Dencaarcene, which is an alumina fiber, is available as a commercial product, but is not limited thereto.

  (A) The shape of the fiber other than the fiber (C) can be used without any particular limitation, and a shape according to the required characteristics can be used, but the strength characteristics such as bending strength and impact resistance can be used. For improvement, it is desirable to use chopped strands. In addition, in order to obtain the yield improvement effect, fibers that are beaten by mechanical shearing force such as a beater or homogenizer, or those that are fibrillated increase the fiber surface area and physically capture the constituent materials. It is desirable to use it because the effect of improving the ability and the effect that the polymer flocculant easily acts chemically are obtained.

  The (B) resin that is a constituent material of the composite resin composition of the present invention may be a thermoplastic resin or a thermosetting resin, and is particularly limited as long as it can act as a binder. For example, acrylonitrile-styrene copolymer (AS) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polycarbonate, polystyrene, polyvinyl chloride, polyester resin, polyamide, polyphenylene sulfide (PPS). ) Thermosetting resins such as resins, acrylic resins, polyethylene, polypropylene, fluororesins, and the like, phenol resins, epoxy resins, unsaturated polyester resins, melamine resins, and polyurethanes. These resins can be appropriately selected and used according to the required properties, and may be used alone or in combination of two or more. Among these, in terms of good mechanical strength and chemical resistance, thermosetting resins are preferable, in terms of good moldability and design properties such as resin transparency, Thermoplastic resins are preferred.

  (B) As a preferable form for using the resin, a solid state having an average particle diameter of 500 μm or less or an emulsion is desirable. More preferably, the average particle size is about 1 nm to 300 μm. As a result, when the polymer flocculant is added, (D) in the presence of a powdery substance having ion exchange ability, the resin and the electromagnetic wave shielding fiber easily form an aggregated state, and the yield is improved. When the average particle size is larger than the above upper limit value, it becomes difficult to form an aggregated state even if a polymer flocculant is added, which causes a decrease in yield. The average particle diameter of the resin (B) is determined, for example, by using a laser diffraction particle size distribution measuring device such as SALD-7000 manufactured by Shimadzu Corporation as the average particle diameter based on a 50% particle diameter. be able to.

  The method for producing the composite resin composition of the present invention is not particularly limited, but after the constituent materials are dispersed in a solvent, a polymer flocculant is added to cause the constituent materials to aggregate in a floc form. A method of removing the solvent after separating the product from the solvent is preferred. The method for dispersing the constituent materials and the like in the solvent is not particularly limited, and examples thereof include a method of stirring with a disperser or a homogenizer. In addition, the method for separating and removing the aggregate from the solvent is not particularly limited, but for example, after separating only by passing the solvent using a net or woven fabric such as metal or plastic, non-woven fabric, Further, there may be mentioned a method of removing the agglomerates by removing the solvent and drying using a press or a dryer. In such a method for producing a composite resin composition, it is more preferable that (D) a powdery substance having ion exchange capacity is further included as a constituent material. In such a method for producing a composite resin composition, (D) by using a powder substance having ion exchange capacity, (A) a high yield while keeping the fiber length of the electromagnetic shielding fiber long, (A) electromagnetic wave Since the aggregate of shielding fiber and (B) resin can be produced efficiently, it becomes possible to adjust the blending ratio of (A) electromagnetic shielding fiber and (B) resin over a wide range. For this reason, according to the required requirements, (A) the electromagnetic shielding properties of the electromagnetic shielding fibers, thermal conductivity, rigidity, and other characteristics, and (B) the balance between the properties of the resin, such as workability and lightness, A wide range of excellent composite resin compositions can be obtained more efficiently.

  (D) The powdery substance having ion exchange ability is preferably at least one intercalation compound selected from clay minerals, scaly silica fine particles, hydrotalcites, fluorine teniolite and swellable synthetic mica.

  The clay mineral is not particularly limited as long as it has ion exchange ability, and examples thereof include smectite, halloysite, kanemite, kenyanite, zirconium phosphate, and titanium phosphate. The hydrotalcite is not particularly limited as long as it has ion exchange capacity, and examples thereof include hydrotalcite and hydrotalcite-like substances. The fluorine teniolite is not particularly limited as long as it has ion exchange ability, and examples thereof include lithium-type fluorine teniolite and sodium-type fluorine teniolite. The swellable synthetic mica is not particularly limited as long as it has ion exchange ability, and examples thereof include sodium tetrasilicon fluorine mica and lithium tetrasilicon fluorine mica. These intercalation compounds may be natural products or those synthesized, and may be used alone or in combination of two or more. Among these, clay minerals are more preferable, and smectite is more preferable in that it exists from natural products to synthetic products and has a wide range of selection.

  The smectite is not particularly limited as long as it has ion exchange ability, and examples thereof include montmorillonite, beidellite, nontronite, saponite, hectorite, soconite, and stevensite. Montmorillonite is a hydrated silicate of aluminum, but may be bentonite containing montmorillonite as a main component and minerals such as quartz, mica, feldspar, and zeolite. Synthetic smectite with few impurities is preferable when used for applications such as coloring and impurities.

  (D) As a powdery substance having ion exchange capacity, for example, Kunipia (bentonite) manufactured by Kunimine Industry Co., Ltd., Smecton SA (synthetic saponite), Sun Lovely (scale-like silica fine particles) manufactured by AGC S-Itech Co., Ltd. , Somasif (swelling synthetic mica), Lucentite (synthetic smectite) manufactured by Corp Chemical Co., Ltd. However, it is not limited to these.

  (D) The content of the powdery substance having ion exchange capacity is preferably 0.1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less of the entire composite resin composition. It is. If it is in the said range, the effect which improves the fixability of the structural material from which a property differs like (A) electromagnetic wave shielding fiber and (B) resin can be acquired. According to the ratio of (A) electromagnetic shielding fiber and (B) resin in the constituent material, and the type and amount of the polymer flocculant, (D) the content of the powdery substance having ion exchange capacity Is preferably adjusted.

  The solvent used for dispersing the constituent materials in the present invention is not particularly limited, but it is difficult to volatilize during the process, it is easy to remove the solvent because it does not remain in the product, and if the boiling point is too high, the solvent is removed. Therefore, from the standpoint of enormous energy consumption, those having a boiling point of 50 ° C. or more and 200 ° C. or less are preferable. Examples of such a material include water, ethanol, 1-propanol, 1-butanol, Alcohols such as ethylene glycol, ketones such as acetone, methyl ethyl ketone, 2-heptanone, cyclohexanone, esters such as ethyl acetate, butyl acetate, methyl acetoacetate, methyl acetoacetate, tetrahydrofuran, isopropyl ether, dioxane, furfural And ethers. These solvents may be used alone or in combination of two or more. Among these, water is particularly preferable because of its abundant supply amount, low cost, low environmental load, high safety and easy handling.

  The polymer flocculant used for aggregating the constituent materials of the composite resin composition of the present invention in a floc form is not particularly limited by ionicity and the like. Cationic polymer flocculant, anionic polymer A flocculant, a nonionic polymer flocculant, an amphoteric polymer flocculant, and the like can be used. Examples of such a material include cationic polyacrylamide, anionic polyacrylamide, Hoffman polyacrylamide, mannic polyacrylamide, amphoteric copolymerized polyacrylamide, cationized starch, amphoteric starch, and polyethylene oxide. These polymer flocculants may be used alone or in combination of two or more. Further, as the polymer flocculant, the polymer structure, molecular weight, functional group amount such as hydroxyl group and ionic group, etc. can be used without particular limitation depending on the required properties.

  Examples of the polymer flocculant include polyethylene oxide manufactured by Wako Pure Chemical Industries, Ltd., Kanto Chemical Co., Ltd., Sumitomo Seika Co., Ltd., and cationic PAM manufactured by Harima Kasei Co., Ltd. Fix, Hermide B-15 which is an anionic PAM, Hermide RB-300 which is an amphoteric PAM, SC-5 which is a cationized starch manufactured by Sanwa Starch Co., Ltd. are commercially available. It is not limited.

  The amount of the polymer flocculant added is not particularly limited, but is preferably 100 ppm by mass or more and 1% by mass or less based on the weight of the constituent material. More preferably, it is 500 mass ppm or more and 0.5 mass%. Thereby, the constituent material can be aggregated with good yield. If the addition amount of the polymer flocculant is smaller than the above lower limit value, the yield may be lowered, and if it is larger than the above upper limit value, the agglomeration is too strong and problems such as dehydration may occur.

  The composite resin composition of the present invention can be adjusted in characteristics by further including (E) at least one filler powder selected from inorganic powders and metal powders as a constituent material. Examples of the inorganic powder include oxides such as titanium oxide, alumina, silica, zirconia, and magnesium oxide, nitrides such as boron nitride, aluminum nitride, and silicon nitride, and barium sulfate, iron sulfate, and copper sulfate. Examples include sulfides, hydroxides such as aluminum hydroxide and magnesium hydroxide, minerals such as kaolinite, talc, natural mica, and synthetic mica, and carbides such as silicon carbide. However, a surface treated with a silane coupling agent, an aluminate coupling agent, a titanate coupling agent or the like may be used depending on the required characteristics.

  Further, the metal powder may be a metal powder composed of a single metal element or an alloy powder composed of a plurality of metals, but the metal element constituting the metal powder may be aluminum, Examples thereof include silver, copper, magnesium, iron, chromium, nickel, titanium, zinc, tin, molybdenum, and tungsten.

  The composite resin composition of the present invention includes the above-mentioned (A) electromagnetic wave shielding fiber, (B) resin, (C) fiber, (D) powdery substance having ion exchange ability, (E) inorganic powder and metal powder. In addition to at least one filler powder selected from the group consisting of polymer flocculants, stabilizers such as antioxidants and ultraviolet absorbers for the purpose of improving properties, mold release agents, plasticizers, flame retardants, and resin curing catalysts And curing accelerators, pigments, dry paper strength improvers, wet strength strength improvers, yield improvers, drainage improvers, size fixers, antifoaming agents, rosin sizing agents for acidic papermaking, Neutral paper rosin sizing agent, alkyl ketene dimer sizing agent, alkenyl succinic anhydride sizing agent, special modified rosin sizing agent, coagulant such as sulfate band, aluminum chloride, polyaluminum chloride, etc. The production condition Sayre, expressing the required physical properties may be used various additives for the purpose of.

The composite resin composition used in the present invention is, as described above, after dispersing the constituent materials and the like in a solvent,
It can be obtained by adding a polymer flocculant, aggregating constituent materials in a floc form, separating the aggregate from the solvent, and then removing the solvent. However, the method is not limited to this method. In addition, a method of forming a composite resin by impregnating a resin by forming an electromagnetic wave shielding fiber and a web with a card machine, a method of blending an electromagnetic wave shielding fiber in the resin, and the like are also included.

  Next, the manufacturing method of the molded object of this invention is demonstrated. The method for producing the molded body of the present invention is not particularly limited, and for example, press molding, compression molding, calender roll molding, SMC method, injection molding, matched die method, metal, resin, woven fabric, nonwoven fabric, etc. And a molding method such as lamination molding.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Further, “parts” described in Examples and Comparative Examples indicate “parts by mass”, and “%” indicates “% by mass”.
The raw materials described in the examples are expressed in parts by mass excluding the moisture content contained in advance.

1. Preparation of composite resin composition (1) Example 1
45 parts of a solid resol resin (PR-51723 manufactured by Sumitomo Bakelite Co., Ltd.) and 2 parts bentonite (trade name Kunipia manufactured by Kunimine Industry Co., Ltd.) pulverized to an average particle size of 100 μm by an atomizer pulverizer, fiber length 5 mm, fiber diameter 1 part of 6 μm stainless fiber (trade name Naslon, manufactured by Nippon Seisen Co., Ltd.), 12 parts of Kevlar (registered trademark) Pulp 1F303 (manufactured by Toray DuPont), Technora (registered trademark) fiber T32PNW (Teijin Techno Products ( 40 parts) was added to 10,000 parts of water and stirred with a disperser for 30 minutes, and then a polyethylene oxide molecular weight of 1,000,000 (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in water in advance was added. Addition of 900 ppm to the constituent material causes the constituent material to aggregate in a floc form. The agglomerates are separated from water with an 80-mesh metal mesh, and then the agglomerates are depressurized and further placed in a drier at 70 ° C. for 6 hours to dry the composite resin composition with a yield of 99%. I got it. Details of the yield measurement method will be described later.

(2) Example 2
45 parts of solid resol resin (PR-51723 manufactured by Sumitomo Bakelite Co., Ltd.) and 5 parts bentonite (trade name Kunipia manufactured by Kunimine Industries Co., Ltd.) pulverized to an average particle size of 100 μm by an atomizer pulverizer, fiber length 5 mm, fiber diameter 4 parts of 6 μm stainless fiber (trade name Naslon manufactured by Nippon Seisen Co., Ltd.), 6 parts of Kevlar (registered trademark) Pulp 1F303 (manufactured by Toray DuPont), Technora (registered trademark) fiber T32PNW (Teijin Techno Products ( 40 parts) was added to 10,000 parts of water and stirred with a disperser for 30 minutes, and then a polyethylene oxide molecular weight of 1,000,000 (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in water in advance was added. Addition of 0.3% to the constituent material causes the constituent material to aggregate in a floc form. The agglomerates are separated from water with an 80-mesh metal mesh, and then the agglomerates are depressurized and further placed in a drier at 70 ° C. for 6 hours to dry the composite resin composition with a yield of 99%. I got it.

(3) Example 3
30 parts of solid resol resin (PR-51723 manufactured by Sumitomo Bakelite Co., Ltd.) and 3 parts bentonite (trade name Kunipia manufactured by Kunimine Industries Co., Ltd.) pulverized to an average particle size of 100 μm with an atomizer pulverizer, fiber length 5 mm, fiber diameter 32 parts of 6 μm stainless fiber (trade name Naslon manufactured by Nippon Seisen Co., Ltd.), 10 parts of Kevlar (registered trademark) Pulp 1F303 (manufactured by Toray DuPont), Technora (registered trademark) fiber T32PNW (Teijin Techno Products ( Co., Ltd.) 25 parts was added to 10,000 parts of water, stirred with a disperser for 30 minutes, and then a polyethylene oxide molecular weight of 1,000,000 (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in water in advance. 0.5% is added to the constituent material, and the constituent material is aggregated in a floc form. The agglomerates are separated from water by an 80 mesh metal mesh, and then the agglomerates are dehydrated and pressed and further dried in a 70 ° C. drier for 6 hours to obtain a composite resin composition with a yield of 96%. I got it.

(4) Example 4
In a freeze pulverizer, 45 parts of pulverized acrylonitrile-styrene copolymer (AS) resin (trade name Sebian N, manufactured by Daicel Industries, Ltd.) pulverized to an average particle size of 300 μm, and flaky silica fine particles (AGC S-Tech ( Product name Sun Lovely Co., Ltd. 5 parts, fiber length 5 mm, fiber diameter 6 μm stainless steel fiber (Nihon Seisen Co., Ltd. product name Naslon) 5 parts, fiber diameter 22 μm, fiber length 5 mm polyvinyl alcohol fiber ((stock) ) Kuraray brand name vinylon) Add 45 parts to 10000 parts water, stir with a disperser for 30 minutes, and then use cationic polyacrylamide (manufactured by Harima Kasei Co., Ltd.) dissolved in water as a constituent material. On the other hand, addition is performed so that the weight becomes 0.4%, and the constituent materials are aggregated in a floc form. The agglomerates are separated from water with a 40-mesh metal mesh, and then the agglomerates are depressurized and placed in a drier at 130 ° C. for 6 hours to dry the composite resin composition at a yield of 92%. I got it.

(5) Example 5
10 parts of epoxy resin 1002 (Mitsubishi Chemical Co., Ltd.) pulverized with a high-pressure homogenizer to an average particle size of 30 μm, 1 part of imidazole epoxy resin curing agent 2PZ-PW (Shikoku Kasei Kogyo Co., Ltd.), synthetic saponite (Kunimine) Industrial Co., Ltd. product name Smecton SA 3 parts, fiber length 3 mm, fiber diameter 60 μm copper fiber (manufactured by Niji Gi) 77 parts, fiber length 5 mm, fiber diameter 6 μm stainless fiber 5 parts (Nippon Seisen ( 4 parts of cellulose pulp (trade name NDPT manufactured by Nippon Paper Chemicals Co., Ltd.) were added to 10,000 parts of water, stirred for 30 minutes with a disperser, and then dissolved in water in advance. Add 0.3% of cationized starch SC-5 manufactured by Wastar Kogyo Co., Ltd. to the constituent materials to aggregate the constituent materials in a floc form. The agglomerates are separated from water with a 40 mesh metal net, and then the agglomerates are depressurized and further dried in a dryer at 100 ° C. for 4 hours to obtain a composite resin composition with a yield of 95%. I got it.

(6) Comparative Example 1
45 parts of solid resole resin (PR-51723 manufactured by Sumitomo Bakelite Co., Ltd.) and 5 parts bentonite (trade name Kunipia manufactured by Kunimine Industries Co., Ltd.), fiber length 5 mm, Kevlar ( (Registered trademark) Pulp 1F303 (manufactured by Toray DuPont Co., Ltd.) 6 parts, Technora (registered trademark) fiber T32PNW (manufactured by Teijin Techno Products Co., Ltd.) 44 parts are added to 10000 parts of water, and 30 minutes with a disperser After stirring, 0.1% of polyethylene oxide molecular weight 1,000,000 (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in water in advance is added to the constituent material, and the constituent material is aggregated in a floc form. . The agglomerates are separated from water with an 80-mesh metal mesh, and then the agglomerates are depressurized and further placed in a drier at 70 ° C. for 6 hours to dry the composite resin composition with a yield of 99%. I got it.

2. Fabrication of molded body (1) Example 6
The composite resin composition obtained in Example 1 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 180 ° C. for 10 minutes under a surface pressure of 30 MPa. A molded body having a size of 10 cm × width 10 cm × thickness 2 mm was obtained.

(2) Example 7
The composite resin composition obtained in Example 2 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 180 ° C. for 10 minutes under a surface pressure of 30 MPa. A molded body having a size of 10 cm × width 10 cm × thickness 2 mm was obtained.

(3) Example 8
The composite resin composition obtained in Example 3 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 180 ° C. for 10 minutes under a surface pressure of 30 MPa. A molded body having a size of 10 cm × width 10 cm × thickness 2 mm was obtained.

(4) Example 9
The composite resin composition obtained in Example 4 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 200 ° C. for 10 minutes under a surface pressure of 15 MPa. The mold was cooled to 0 ° C. to obtain a molded body having a length of 10 cm × width of 10 cm × thickness of 2 mm.

(5) Example 10
The composite resin composition obtained in Example 5 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 160 ° C. for 60 minutes under a surface pressure of 10 MPa. A molded body having a size of 10 cm × width 10 cm × thickness 2 mm was obtained.

(7) Comparative Example 2
The composite resin composition obtained in Comparative Example 1 was set in a mold coated with a release agent, and the composite resin composition was subjected to compression molding at 180 ° C. for 10 minutes under a surface pressure of 30 MPa. A molded body having a size of 10 cm × width 10 cm × thickness 2 mm was obtained.

  Using the molded bodies obtained in Examples 6 to 10 and Comparative Example 2, the following characteristic evaluation was performed. The results are shown in Table 1.

3. 3. Evaluation method of characteristic 3.1 Composite resin composition (1) Yield It was calculated by the following formula.
Yield (%) = (weight of obtained composite resin composition / total weight of prepared composite resin composition material) × 100
About the obtained composite resin composition, the weight after drying was used, and the total weight of the prepared composite resin composition raw material was the amount from which moisture was removed.

3.2 Molded body

(1) Specific gravity measurement Specific gravity measurement was performed in accordance with JIS K 6911 (General Test Method for Thermosetting Plastics). The test piece used was cut from the molded body so as to be 2 cm long × 2 cm wide × 2 mm thick.

(2) Measurement of electromagnetic wave shielding rate A molded body having a length of 12 cm, a width of 12 cm, and a thickness of 1 mm was produced under the same molding conditions as those obtained for a molded body having a length of 10 cm, a width of 10 cm, and a thickness of 2 mm. Used as. Next, evaluation was performed by the KEC method. The KEC method is a measurement method performed by the Kansai Electronics Industry Promotion Center, where a test piece is sandwiched between symmetrically divided shield boxes, and the attenuation of electromagnetic waves through the test piece is measured with a spectrum analyzer. is there.
An example of the relationship between the electromagnetic wave shielding property and the electromagnetic wave shielding rate is shown below.
The electromagnetic wave shielding property of 60 dB indicates an electromagnetic wave shielding rate of 99.9%.
The electromagnetic wave shielding property of 40 dB indicates an electromagnetic wave shielding rate of 99.0%.
The electromagnetic wave shielding 20 dB indicates an electromagnetic wave shielding rate of 90.0%.

(3) Bending test The bending test was performed in accordance with JIS K 6911 (thermosetting plastic general test method). The test piece used was cut from the molded body so as to be 50 mm long × 25 mm wide × 2 mm thick. The distance between fulcrums in the bending test was 32 mm.

(4) Measurement of the coefficient of linear expansion in the plane direction Molding with a length of 5 mm x width of 30 mm x length of 10 mm, with the molding time only being three times the molding conditions for obtaining a molded product of 10 cm long x 10 cm wide x 2 mm thick The body was cut into 5 mm long x 5 mm wide x 10 mm long test pieces, and the coefficient of linear expansion in the length direction was determined using a thermomechanical analyzer (manufactured by Seiko Instruments Inc., TMA-6000). It was measured. The rate of temperature increase was 5 ° C./min, and the linear expansion coefficient (α1) was determined in the temperature range of 80 to 120 ° C.

Examples 1 to 5 are composite resin compositions obtained by the present invention, and Examples 6 to 10 are molded articles obtained by the present invention.
In all of Examples 1 to 5, composite resin compositions were obtained in high yield. Further, in all of Examples 6 to 10, the 800 MHz electric field shielding property is 20 dB or more, the bending strength is 80 MPa or more, the bending elastic modulus is 8 GPa or more, the specific gravity is 1 to 5 and the linear expansion in the plane direction It was found that a molded article having a coefficient balance of 0.1 ppm / ° C. or more and 50 ppm / ° C. or less and having an excellent balance of properties can be obtained. On the other hand, the molded body of Comparative Example 2 was not effective in shielding the electric field wave. From this, it can be seen that according to the present invention, it is possible to obtain a molded article having an excellent balance between characteristics such as processability and light weight and characteristics such as electromagnetic wave shielding and rigidity.

According to the present invention, it is possible to obtain a molded article excellent in the balance of properties such as resin processability, lightness, linear expansion coefficient, electromagnetic wave shielding property, and rigidity.
Therefore, the molded product obtained from the composite resin composition of the present invention is a personal computer, a mobile phone, a portable information terminal, a plasma display television, a liquid crystal television, an OA device, a game device, an entertainment product, an air conditioner, an audio, an optical device, and an illumination. Can be used for electronic products such as appliances, internal mechanical parts of automotive electronic products, components such as housings, and structural parts for construction, parts for aerospace, space, automobiles, etc. Thus, it is possible to contribute to the reduction of the plating process, the improvement of fuel efficiency and the energy saving in the weight reduction, and the environmental load can be reduced.

Claims (18)

As a constituent material, it is a composite resin composition containing (A) electromagnetic wave shielding fiber and (B) resin,
The molded product obtained by molding the resin composition has an 800 MHz electric field shielding property measured by the KEC method of 20 dB or more, a bending strength measured in accordance with JIS K 6911 of 80 MPa or more, and a flexural modulus. 8 GPa or more, a specific gravity measured in accordance with JIS K 6911 is 1 or more and 5 or less, and a linear expansion coefficient in a plane direction is 0.1 ppm / ° C. or more and 50 ppm / ° C. or less. object.   2. The composite resin composition according to claim 1, wherein the (A) electromagnetic shielding fiber has an average fiber length of 500 μm or more and 10 mm or less.   The composite resin composition according to claim 1 or 2, wherein the content of the (A) electromagnetic wave shielding fiber is 1% by mass or more and 90% by mass or less of the entire composite resin composition.   The composite resin composition according to any one of claims 1 to 3, wherein the electromagnetic shielding fiber (A) includes a metal fiber.   The composite resin composition according to claim 4, wherein the metal element constituting the metal fiber includes at least one metal element selected from iron, silver, nickel, aluminum, and copper.   The composite resin composition according to any one of claims 1 to 5, further comprising (C) a fiber other than the (A) electromagnetic wave shielding fiber as the constituent material.   The fiber of the component (C) other than the (A) electromagnetic wave shielding fiber is natural fiber such as wood fiber, cotton, hemp, wool, regenerated fiber such as rayon fiber, semi-synthetic fiber such as cellulose fiber, polyamide fiber, Synthetic fibers such as aramid fiber, polyimide fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber polyparaphenylene benzoxazole fiber, polyethylene fiber, polypropylene fiber, polyacrylonitrile fiber, ethylene vinyl alcohol fiber, glass fiber, ceramic fiber, etc. The composite resin composition according to claim 6, comprising at least one fiber selected from inorganic fibers.   The composite resin composition according to any one of claims 1 to 7, wherein an average particle size of the resin (B) is 500 µm or less. A composite resin composition obtained by dispersing the constituent material in a solvent, adding a polymer flocculant, aggregating the constituent material in a floc form, separating the aggregate from the solvent, and then removing the solvent. Because
The composite resin composition according to any one of claims 1 to 8, further comprising (D) a powdery substance having ion exchange capacity as the constituent material.   (D) The powdery substance having ion exchange capacity is at least one intercalation compound selected from clay minerals, scaly silica fine particles, hydrotalcites, fluorine teniolite and swellable synthetic mica. The composite resin composition according to claim 9.   10. The composite according to claim 9, wherein the powdery substance having ion exchange capacity (D) contains at least one clay mineral selected from smectite, halloysite, kanemite, kenyanite, zirconium phosphate, and titanium phosphate. Resin composition.   The powdery substance having ion exchange capacity (D) contains at least one smectite selected from montmorillonite, beidellite, nontronite, saponite, hectorite, soconite and stevensite. The composite resin composition as described.   The composite resin composition according to claim 9, wherein the powdery substance having (D) ion exchange capacity contains montmorillonite.   The content of the powdery substance having (D) ion exchange capacity is 0.1% by mass or more and 30% by mass or less based on the entire composite resin composition. A composite resin composition as described in 1. above.   The composite resin composition according to any one of claims 1 to 14, further comprising (E) at least one filler powder selected from an inorganic powder and a metal powder as the constituent material.   The metal element constituting the metal powder includes at least one metal element selected from aluminum, silver, copper, magnesium, iron, chromium, nickel, titanium, zinc, tin, molybdenum, and tungsten. 15. The composite resin composition according to 15.   The composite resin composition according to any one of claims 9 to 16, wherein a boiling point of the solvent is 50 ° C or higher and 200 ° C or lower. A molded article having excellent electromagnetic shielding properties, comprising the composite resin composition according to any one of claims 1 to 17.