Member for electronic device housing

Abstract

This member for an electronic device case is provided with: a plate-like member having a fiber-reinforced plastic; and a thermoplastic resin member integrated with at least a portion of the peripheral region of the plate-shaped member, the thermoplastic resin member containing reinforcing fibers A and a thermoplastic resin D, a portion of the reinforcing fibers A being dispersed in a monofilament shape, the other portion of the reinforcing fibers A not being dispersed in a monofilament shape, and the thermoplastic resin D being dispersed in a monofilament shape. However, the plurality of monofilaments are randomly arranged in the form of a bunched part (E) composed of the plurality of monofilaments. According to the present invention, it is possible to provide a member for an electronic device case having good impact resistance.

Description

Technical Field

[0001] The present invention relates to a housing member for electronic equipment. Background Art

[0002] Fiber reinforced plastics (FRP) containing reinforcing fibers and matrix resins are lightweight and have excellent mechanical properties, so they can be widely used in various industrial applications. At present, with the development of portable electrical and electronic equipment such as personal computers, OA equipment, AV equipment, mobile phones, telephones, fax machines, home appliances, toys, etc., further miniaturization and lightweight are required. In order to achieve this requirement, the components (especially the housing) constituting the equipment are required to achieve high strength, high rigidity, and thin-walled, so as to avoid the housing from being greatly bent and contacting with internal components and causing damage when a load is applied from the outside. For the molded structure that is made small and lightweight by integrating the fiber reinforced resin structure containing reinforcing fibers and resin with other components (such as frame components), further thinning without warping and reliability of bonding strength are required.

[0003] In order to achieve lightweight, many strategies have been proposed: as a laminate with a sandwich structure, a low-density material is used in the core layer to reduce the overall specific gravity of the product, thereby achieving lightweight; a technology that provides gaps inside the sandwich structure to reduce the overall density of the product.

[0004] Patent document 1 proposes an integrated molded body, in which a bonding resin is present between a plate material whose single-side surface is a design surface and a component. In the integrated molded body, there is a bonding portion in which the plate material and the component are arranged in a manner to separate the plate material and the outer peripheral edge portion of the plate material is bonded to the bonding resin, and at least a portion of the surface on the design surface side of the aforementioned integrated molded body has an area where the plate material, the aforementioned component, and the aforementioned bonding resin are exposed. By making such an integrated molded body, a plurality of structures are bonded with high bonding strength, and the bonding boundary portion has good smoothness, so that even if the molded body has a constituent component of the plate material, warping is reduced.

[0005] Patent Document 2 proposes to use a fiber-reinforced resin pellet using reinforcing fibers having different fiber lengths to increase the reinforcing fiber filling and improve mechanical properties, fluidity, appearance, and productivity.

[0006] In addition, scraps and scraps generated in the process of manufacturing products made of FRP, as well as waste materials formed from FRP products as discarded objects, are difficult to recycle due to their nature, and are usually landfilled after being crushed or incinerated. The problem of landfill sites and the problem of environmental hormones generated by epoxy resins have gradually become social problems, so as to establish recycling technology, research has been conducted on: thermal recycling, that is, incinerating waste materials, scraps, etc., and recovering the heat energy during incineration; material recycling, that is, adding these waste materials to the raw materials when manufacturing other products for reuse.

[0007] Patent document 3 proposes a method of thermally decomposing the matrix resin of CFRP waste and heating it in such a way that the weight of the resin residue becomes 0.1 to 6% of the carbon fiber bundle, thereby providing a recycled carbon fiber bundle having bundling properties that have no problems in passing the process, excellent reinforcement effect, and excellent dispersibility into the matrix resin.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent No. 6447127

[0011] Patent Document 2: Japanese Patent Application Publication No. 2006-181776

[0012] Patent Document 3: Japanese Patent Application Publication No. 2017-002125 Summary of the invention

[0013] Problems to be solved by the invention

[0014] However, the physical properties of the obtained molded product cannot necessarily be said to be sufficiently improved with the bonding resin used in Patent Document 1. In addition, the method of Patent Document 2 aims to uniformly disperse the reinforcing fibers, and there is no concept of bundling the reinforcing fibers. In addition, it is described that recycled materials can be used as short fiber reinforced thermoplastic resin pellets, but there is no concept of recycling the molded product.

[0015] The batch heat treatment proposed in Patent Document 3 is not sufficiently productive and is costly. If crushing and heating are performed continuously to improve productivity, the bundling is insufficient, clogging occurs in the process, and the process is not sufficiently operable, making it unsuitable for industrial use. In addition, the superiority of using recycled carbon fiber bundles as reinforcing fibers cannot be demonstrated in comparison with virgin materials.

[0016] The present invention is made to solve the problems associated with the above-mentioned prior art, and the subject is to provide a component for an electronic device housing, which has: a plate-like component having fiber-reinforced plastic; and a thermoplastic resin component integrated with at least a portion of the peripheral area of ​​the aforementioned plate-like component, and has impact resistance that makes it difficult for cracks to be generated due to impacts applied when the electronic device housing is dropped, etc.

[0017] Means for solving problems

[0018] In order to solve the above problems, the present invention has the following configuration.

[0019] (1) A member for an electronic device housing, comprising: a plate-like component comprising fiber-reinforced plastic; and a thermoplastic resin component integrated with at least a portion of a peripheral region of the plate-like component, the thermoplastic resin component comprising reinforcing fibers A and a thermoplastic resin D, a portion of the reinforcing fibers A being dispersed in a monofilament form, and another portion of the reinforcing fibers A being not dispersed in a monofilament form but being randomly arranged in the form of a bundle E consisting of a plurality of monofilaments.

[0020] (2) The electronic device casing member according to the above (1), wherein the content of the reinforcing fiber A in the thermoplastic resin component is 1 to 50% by mass.

[0021] (3) The electronic device casing member according to (1) or (2) above, wherein 0.1 to 30 parts by mass of a resin H different from the thermoplastic resin D is adhered to the surface of the monofilament constituting the bundled portion E, relative to 100 parts by mass of the reinforcing fiber A contained in the bundled portion E.

[0022] (4) The electronic device casing member according to any one of (1) to (3) above, wherein the average fiber diameter of the single fibers in the reinforcing fibers A of the thermoplastic resin component is 4.0 to 30.0 μm.

[0023] (5) The electronic device casing member according to any one of (1) to (4) above, wherein the plate-like member is a sandwich structure formed of a core material and fiber reinforced plastics bonded to both surfaces of the core material.

[0024] (6) A component for an electronic device casing as described in any one of (1) to (5) above, wherein the reinforcing fiber A includes two types of reinforcing fibers, reinforcing fiber B and reinforcing fiber C, whose average fiber diameters of the single filaments are different from each other, the reinforcing fiber B does not form the bundle portion E, a portion of the reinforcing fiber C is dispersed in the form of single filaments, and another portion of the reinforcing fiber C constitutes the bundle portion E.

[0025] (7) The electronic device casing member according to the above (6), wherein a mass ratio B / C of the reinforcing fibers B to the reinforcing fibers C is 99 / 1 to 40 / 60.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to obtain an electronic device casing member having excellent impact resistance as an electronic device casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [ Figure 1 ] is a schematic diagram of a component for an electronic device housing according to one embodiment of the present invention.

[0029] [ Figure 2 ] Figure 1 A partial cross-sectional schematic perspective view of a component for an electronic device housing.

[0030] [ Figure 3 ] is a schematic stereoscopic view showing a partial cross section of a component for an electronic device housing according to another embodiment of the present invention using a plate-like component having a sandwich structure.

[0031] [ Figure 4 ] is a schematic perspective view showing a partial cross section of a component for an electronic device housing according to another embodiment of the present invention in which the thermoplastic resin component has a rib shape. DETAILED DESCRIPTION

[0032] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments and the accompanying drawings. The present invention can be implemented by appropriately adding changes within the scope of its purpose.

[0033] The electronic device housing member of the present invention comprises: a plate-shaped member having fiber-reinforced plastic; and a thermoplastic resin member integrated with at least a portion of the peripheral region of the plate-shaped member, wherein the thermoplastic resin member comprises reinforcing fibers A and a thermoplastic resin D, at least a portion of the reinforcing fibers A being dispersed in a monofilament form, and at least another portion of the reinforcing fibers A being not dispersed in a monofilament form but being randomly arranged in the form of a bundle E consisting of a plurality of monofilaments.

[0034] An example of the electronic device housing member of the present invention is shown in Figure 1 .exist Figure 1 In the embodiment, the electronic device casing member 1 is formed by integrating the plate-shaped member 2 and the thermoplastic resin member 3 , and the thermoplastic resin member 3 includes the bundled portion E4 .

[0035] in addition, Figure 2 Shown from another angle Figure 1 Components for electronic equipment housings. Figure 2 In FIG. 1 , the thermoplastic resin member 3 is shown to be integrated with the peripheral edge portion of the plate-like member 2 .

[0036] in addition, Figure 4 Another example of the electronic device casing member of the present invention is shown in FIG. Figure 4 This is a schematic perspective view showing a partial cross section of the electronic device housing member 1 when the thermoplastic resin component 3 has a concavo-convex shape 7 (rib shape) for reinforcement. Figure 4 In the example shown, the concavo-convex shape 7 (rib shape) is formed on the inner side (plate-like member 2 side) of the thermoplastic resin member 3, and the outer surface can be used as a design surface, but for the purpose of reinforcement, the concavo-convex shape 7 (rib shape) may be provided on the outer side of the thermoplastic resin member 3 or on a part of the inner side or the outer side.

[0037] (Plate-shaped parts)

[0038] The plate-like member is a substantially flat plate, which means that the aspect ratio formed by the long side and the thickness of the plate-like member is greater than 10. The plate-like member may have concave and convex portions, holes, an arch, an inclined surface, and different thicknesses.

[0039] In the present invention, at least a part of the plate-like member is formed of a fiber-reinforced plastic in which reinforcing fibers are impregnated with a thermosetting resin or a thermoplastic resin.

[0040] In the present invention, the plate-shaped member comprises a fiber-reinforced plastic. That is, at least a portion of the plate-shaped article in the present invention is formed of a fiber-reinforced plastic in which reinforcing fibers are impregnated with a thermosetting resin or a thermoplastic resin.

[0041] The fiber reinforced plastic may be composed of a fiber reinforced plastic monomer, or may be a sandwich structure formed by a core material and fiber reinforced plastics bonded to both sides of the core material. In the sandwich structure, by making the core material a material with a small specific gravity, it is possible to maintain rigidity while making the plate-like component lightweight as a whole. In addition, from the perspective of lightness, in the sandwich structure, a sandwich structure in which the core material is a sheet-like intermediate substrate obtained by impregnating a thermosetting resin or a thermoplastic resin in a reinforcing fiber mat, or a sandwich structure having pores is preferred.

[0042] Figure 3 1 shows an example of the electronic device casing member of the present invention using a plate-like member having a sandwich structure. Figure 3 This is a schematic perspective view showing a partial cross section of a plate-like member 2 having a sandwich structure formed of a skin material 5 (Japanese: sukin material) and a core material 6, in which a plate cross section is visible.

[0043] The above-mentioned reinforcing fiber mat preferably takes the form of a non-woven fabric. By taking the form of a non-woven fabric, it is easy to impregnate the thermosetting resin or thermoplastic resin into the reinforcing fiber mat. In addition, the reinforcing fiber mat has a higher anchoring effect on the thermosetting resin or thermoplastic resin, and the bonding property is easy to become excellent. The so-called non-woven fabric form refers to a form in which the bundles and / or monofilaments of the reinforcing fibers are irregularly dispersed into a planar form. Examples of non-woven fabric forms include chopped strand mats, continuous strand mats, papermaking mats, carded cotton mats, air-laid mats, etc. The reinforcing fibers in the reinforcing fiber mat may be the same as or different from the reinforcing fibers used in the skin material. It should be noted that the so-called skin material refers to a fiber-reinforced plastic bonded to both sides of the core material in a sandwich structure material.

[0044] As the example of the resin constituting the above-mentioned foam, polyurethane resin, phenolic resin, melamine resin, acrylic resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyetherimide resin, polymethacrylimide resin etc. can be enumerated.Wherein, in order to ensure lightness, it is preferred to use a resin having an apparent density less than that of a leather material.Specifically, polyurethane resin, acrylic resin, polyethylene resin, polypropylene resin, polyetherimide resin, polymethacrylimide resin are preferred.

[0045] Examples of thermosetting resins used in the fiber reinforced plastics include unsaturated polyester resins, vinyl ester resins, epoxy resins, phenolic resins, urea resins, melamine resins, polyimide resins, cyanate resins, bismaleimide resins, benzoxazine resins, copolymers thereof, modified products thereof, and resins obtained by blending at least two of these. Among these, epoxy resins are preferred because of their excellent mechanical properties, heat resistance, and adhesion to reinforcing fibers.

[0046] Examples of the thermoplastic resin used in the fiber-reinforced plastic include styrene resins, fluororesins, polyoxymethylene, polyamide, polyester, polyimide, polyamideimide, vinyl chloride, olefin resins, thermoplastic elastomers, polyacrylates, polyphenylene ethers, polycarbonates, polyether sulfones, polyetherimides, polyether ketones, polyether ether ketones, polyarylether sulfides, cellulose acetate, cellulose acetate butyrate, cellulose derivatives such as ethyl cellulose, liquid crystalline resins, and modified materials thereof or blends of two or more thereof.

[0047] The reinforcing fibers used in the aforementioned fiber reinforced plastics may be continuous reinforcing fibers or may be reinforcing fibers containing discontinuous reinforcing fibers in a portion thereof. Here, continuous reinforcing fibers refer to reinforcing fibers that are continuous in at least one direction with a length of more than 100 mm. In addition, an aggregate of a plurality of reinforcing fibers arranged in a single direction, i.e., a so-called reinforcing fiber bundle, is continuous over the entire length of the plate-like component. Discontinuous reinforcing fibers refer to reinforcing fibers that are not continuous in one direction with a length of more than 100 mm, and are reinforcing fibers with different arrangement directions.

[0048] Examples of the reinforcing fibers used in the fiber-reinforced plastics include metal fibers such as aluminum, brass, and stainless steel, insulating fibers such as polyacrylonitrile (PAN), rayon, lignin, and asphalt carbon fibers, graphite fibers, and glass, organic fibers such as aramid, polyparaphenylene benzobisoxazole (PBO), polyphenylene sulfide, polyester, acrylic resin, nylon, and polyethylene, and inorganic fibers such as silicon carbide and silicon nitride.

[0049] The reinforcing fibers used in the fiber reinforced plastics may be subjected to surface treatment. Examples of surface treatment include treatment with a coupling agent, treatment with a sizing agent, treatment with a sizing agent, and treatment with an additive, in addition to treatment with a metal coating to serve as a conductor.

[0050] Among them, from the viewpoint of the weight reduction effect, it is preferred to use carbon fibers such as PAN, pitch, and rayon that are excellent in specific strength and specific rigidity. In addition, from the viewpoint of improving the conductivity of the resulting molded article, reinforcing fibers coated with metals such as nickel, copper, and ytterbium may also be used.

[0051] The reinforcing fibers used in the fiber-reinforced plastics may be used alone or in combination of two or more.

[0052] In order to improve the adhesion with the thermoplastic resin member, the plate-like member preferably also includes a thermoplastic resin layer as required. In addition, the plate-like member may include different materials such as metals depending on the purpose.

[0053] As an example of a method for manufacturing a plate-like component having fiber-reinforced plastic, the following method can be cited: prepregs containing reinforcing fibers and uncured thermosetting resin, or thermoplastic resin, or a mixture of thermoplastic resin and thermosetting resin are stacked, and heated and pressurized, or cooled while pressurized after heating, thereby making a cured product of the fiber-reinforced resin.

[0054] The prepreg comprising reinforcing fibers and uncured thermosetting resin, or thermoplastic resin, or a mixture of thermoplastic resin and thermosetting resin can be prepared, for example, by impregnating uncured thermosetting resin, or thermoplastic resin, or a mixture of thermoplastic resin and thermosetting resin into a reinforcing fiber bundle or a woven fabric of reinforcing fibers in which reinforcing fibers are arranged in one direction using a known method. In addition, commercially available materials can also be used as such prepregs.

[0055] The molding method for molding the plate-like member is not particularly limited, but from the viewpoint of mass productivity, press molding is preferably performed by laminating uncured materials and then pressurizing them with a press machine to obtain a plate-like member.

[0056] (Thermoplastic resin parts)

[0057] In the electronic device casing member of the present invention, the thermoplastic resin component contains the reinforcing fiber A and the thermoplastic resin D.

[0058] (Reinforcement Fiber A)

[0059] As the reinforcing fiber A, glass fiber, carbon fiber, aramid fiber, metal fiber, etc. can be cited, and it can be appropriately selected according to the desired purpose. Among them, from the aspect of good mechanical properties of injection molded products, glass fiber and carbon fiber are preferred, and further, from the aspect of good impact resistance and electromagnetic wave shielding brought about by imparting conductivity, carbon fiber is more preferred.

[0060] The average filament diameter of the reinforcing fiber A is preferably 4.0 to 30 μm, more preferably 4.2 to 25 μm, and further preferably 4.5 to 20 μm. When the average filament diameter is 4.0 μm or more, the effort of obtaining the desired reinforcing fiber content is omitted, and pellets are easily prepared. When the average filament diameter is 30 μm or less, impregnation with a thermoplastic resin becomes easy, and dispersibility during injection molding is improved, and fine part filling is easily improved.

[0061] Here, the term "detail filling" means that the reinforcing fiber A and the thermoplastic resin reach the details of the small space provided in the mold or the like. If the detail filling is poor, the following may occur: Figure 4 In the space having a length of 2 mm or less in at least one direction such as the rib 7 shown, the reinforcing fiber A is not filled but only the thermoplastic resin is formed; neither the thermoplastic resin nor the reinforcing fiber A is filled, and the shape of the rib becomes insufficient.

[0062] The reinforcing fiber A may include a plurality of reinforcing fibers having different average monofilament diameters according to the purpose. The reinforcing fiber A may include three or more reinforcing fibers. In the electronic device housing member of the present invention, the reinforcing fiber A of the thermoplastic resin component is preferably: the average fiber diameter of the monofilament is 4.0 to 30.0 μm, and includes two reinforcing fibers, reinforcing fiber B and reinforcing fiber C, whose average fiber diameters of the monofilaments are different from each other, the reinforcing fiber B does not form the bundle E, at least a portion of the reinforcing fiber C is dispersed in a monofilament form, and at least another portion of the reinforcing fiber C constitutes the bundle E. By making the reinforcing fiber C a material having better fluidity than the reinforcing fiber B, it is possible to further improve the fine filling property while maintaining the impact resistance of the obtained molded product.

[0063] In the electronic device housing component of the present invention, the mass ratio B / C of the aforementioned reinforcing fiber B and the aforementioned reinforcing fiber C is preferably 99 / 1 to 40 / 60. The mass ratio B / C is more preferably 99 / 1 to 50 / 50, and further preferably 99 / 1 to 60 / 40. If the mass ratio B / C is 40 / 60 or more, that is, in the total of 100 mass% of the aforementioned reinforcing fiber B and the aforementioned reinforcing fiber C, the content of the aforementioned reinforcing fiber B is 40 mass% or more, it is easy to improve the impact resistance of the obtained molded product. In addition, if the mass ratio B / C is less than 99 / 1, that is, if the content of the aforementioned reinforcing fiber C is 1 mass% or more, the fluidity during molding is easily improved, and the filling property of the details is easily improved, which is preferred from this aspect.

[0064] From the viewpoint of obtaining high strength, the tensile strength of the reinforcing fiber A is preferably 3000 MPa or more, more preferably 3250 MPa or more, and even more preferably 3500 MPa or more.

[0065] From the viewpoint of obtaining a high elastic modulus, the tensile elastic modulus of the reinforcing fiber A is preferably 200 GPa or more, more preferably 225 GPa or more, and even more preferably 400 GPa or more.

[0066] In the electronic device housing component of the present invention, the content of the aforementioned reinforcing fiber A in 100% by mass of the aforementioned thermoplastic resin component is preferably 1 to 50% by mass. The content of the reinforcing fiber A is more preferably 1 to 45% by mass, and further preferably 1 to 40% by mass. If the content of the reinforcing fiber A is 1% by mass or more, the physical properties of the molded product obtained by the reinforcing fiber are easily improved. If it is 50% by mass or less, the fluidity during molding is improved, and the filling property of the fine parts is easily improved.

[0067] (Thermoplastic resin D)

[0068] In the component for electronic device housing of the present invention, the thermoplastic resin D is not particularly limited, and examples thereof include polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, ABS resin, polystyrene resin, acrylonitrile styrene (AS) resin, methacrylic resin, polyvinyl alcohol resin, ethylene-vinyl acetate copolymer (EVA) resin, cellulose resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, thermoplastic polyester resin, polytetrafluoroethylene resin, fluorine resin, polyphenylene sulfide resin, polysulfone resin, amorphous polyarylate resin, polyetherimide resin, polyethersulfone resin, polyetherketone resin, liquid crystal polyester resin, polyamideimide resin, polyimide resin, polyarylethernitrile resin, polybenzimidazole resin, etc. Among them, from the perspective of good mechanical properties of injection molded products, polyethylene resin, polypropylene resin, ABS resin, polystyrene resin, AS resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, thermoplastic polyester resin, polyphenylene sulfide resin are preferred, and polyamide resin, polycarbonate resin, and ABS resin are more preferred. These thermoplastic resins can be used alone, or as a mixture, or as a copolymer. In the case of a mixture, a solubilizing agent can be used in combination.

[0069] The thermoplastic resin D may contain additives such as a flame retardant, and these additives can be appropriately used depending on the intended purpose.

[0070] (Method for producing thermoplastic resin parts)

[0071] As an example of a method for producing the aforementioned thermoplastic resin part, there can be cited a method using a molding material mixture, wherein the molding material mixture includes: fiber-reinforced thermoplastic resin pellets F formed from reinforcing fibers A and a thermoplastic resin D; and fiber bundle-reinforced thermoplastic resin pellets G formed from reinforcing fibers A and a thermoplastic resin D and including a specific reinforcing fiber bundle I.

[0072] The form of the fiber-reinforced thermoplastic resin pellets F is not particularly limited, but is preferably a pellet in which the thermoplastic resin D is arranged to cover the periphery of the reinforcing fibers A. As a means of obtaining such pellets, for example, the following method can be cited: a bundle of reinforcing fibers A is passed through a coating die for wire coating installed at the front end of an extruder, and the thermoplastic resin D is extruded and coated to obtain a wire-shaped wire bundle. The wire bundle is cut into a predetermined length by a tow cutter, thereby obtaining a fiber-reinforced thermoplastic resin pellet F having a reinforcing fiber length substantially the same as the length of the pellets.

[0073] The shape of the fiber-reinforced thermoplastic resin pellets F is not particularly limited, and is preferably a cylindrical shape with a diameter of 1 to 5 mm and a pellet length of 1 to 15 mm. If the diameter is 1 mm or more, it is easy to manufacture. In addition, if the diameter is 5 mm or less, it is easy to bite into the molding machine during injection molding and easy to supply. The pellet length is also the reinforcing fiber length, so if the pellet length is 1 mm or more, it is easy to fully obtain the characteristics of the present invention. In addition, if the pellet length is 15 mm or less, it is easy to supply to the molding machine.

[0074] In the fiber-reinforced thermoplastic resin pellets F, from the viewpoint of easily improving the dispersion effect of the reinforcing fibers A in the thermoplastic resin D during molding, a resin J different from the thermoplastic resin D may be attached to the surface of the single yarn of the reinforcing fibers A. The melt viscosity of the resin J is preferably lower than that of the thermoplastic resin D. By making the melt viscosity lower than that of the thermoplastic resin D, the fluidity of the resin J is high when the thermoplastic resin part is molded, and the dispersion effect of the reinforcing fibers A in the thermoplastic resin D can be further improved.

[0075] The resin J is preferably a resin selected from the group consisting of epoxy resins, phenol resins, terpene resins, and cyclic polyphenylene sulfide.

[0076] The amount of the resin J deposited is preferably 0.1 to 20 parts by mass, more preferably 3 to 10 parts by mass, based on 100 parts by mass of the fiber-reinforced thermoplastic resin pellets F. By setting the amount within this range, a molding material having excellent moldability and handling properties can be easily obtained.

[0077] The extruder used in the preparation of the fiber-reinforced thermoplastic resin pellets F is not particularly limited and may be any of a single-screw type and a twin-screw type. In addition, the screw shape of the extruder may also be a general-purpose full-screw, twin-screw type, or a screw with a high-dispersion secondary screw flight such as Dulmadge or Madoc.

[0078] The shape of the fiber bundle reinforced thermoplastic resin pellets G is not particularly limited, but is preferably a cylindrical shape with a diameter of 1 to 5 mm and a pellet length of 1 to 15 mm. If the diameter is 1 mm or more, the manufacturing becomes easy. In addition, if the diameter is 5 mm or less, it is easy to bite into the molding machine during injection molding and easy to supply.

[0079] The reinforcing fiber bundle I used in the fiber bundle reinforced thermoplastic resin pellet G is not limited to a method of forming the bundle as long as at least a part of it is not dispersed in the form of a single filament after being integrally molded with a plate-like component, but exists in the form of a bundle portion E composed of a plurality of single filaments. The reinforcing fiber bundle I may also be a fiber reinforced plastic sheet obtained by crushing a fiber reinforced plastic formed from a thermoplastic resin or a thermosetting resin having a melting point sufficiently higher than that of the injection resin, or a fiber reinforced plastic sheet obtained by crushing, classifying, and heat-treating for recycling. From the perspective of reducing waste to be landfilled, it is preferably a recycled fiber reinforced plastic obtained by crushing, classifying, and heat-treating waste fiber reinforced plastic using a thermosetting resin. From the perspective of having good physical properties of the reinforcing fiber bundle, the recycled fiber reinforced plastic is preferably CFRP (carbon fiber reinforced plastic) using carbon fibers.

[0080] As a method for obtaining recycled fiber-reinforced plastics, known production methods can be mentioned.

[0081] For example, there is a method of obtaining a recycled fiber-reinforced plastic by performing the following steps (a) to (g).

[0082] (a) a crushing process step of crushing the fiber reinforced plastic waste to produce fiber reinforced plastic crushed pieces having a predetermined fiber length;

[0083] (b) a transporting and storing step, in which the fiber-reinforced plastic crushed pieces are transported to a hopper and stored;

[0084] (c) a powder removal step of quantitatively supplying the fiber reinforced plastic crushed pieces from the hopper to a powder removal device, removing powder contained in the fiber reinforced plastic crushed pieces by the powder removal device, and generating fiber reinforced plastic powder removal pieces;

[0085] (d) a thermal decomposition treatment step of heating the fiber reinforced plastic powder removal sheet while quantitatively supplying it to a thermal decomposition furnace to remove the matrix resin component contained in the fiber reinforced plastic powder removal sheet to obtain a recycled reinforcing fiber thermal decomposition product;

[0086] (e) a cooling and conveying step of conveying the recycled reinforcing fiber thermal decomposition product to the next step while cooling it;

[0087] (f) a classification step of classifying the recycled reinforcing fiber thermal decomposition product to obtain a recycled reinforcing fiber classification product;

[0088] (g) An iron removal step of removing metal powder from the recycled reinforcing fiber fractionated body by using magnetic force.

[0089] The method of the crushing process is not particularly limited. In order to effectively crush, it is preferred to use two or more crushers. In an example of using two or more crushers, the fiber reinforced plastic waste as a raw material is first put into a primary crusher, and after being roughly crushed, it is transported to a secondary or subsequent crusher for crushing. It is preferred to crush in the final crusher to a size below the mesh size of a screen set to a desired size.

[0090] The conveying method in the conveying and storing step is not particularly limited, and the fiber reinforced plastic crushed pieces generated in the crushing process and the powder generated in the crushing process from the fiber reinforced plastic waste are preferably conveyed and stored in a hopper by air conveying, belt conveyor, bucket conveyor, etc. Among them, air conveying is more preferred from the perspective of low equipment cost.

[0091] The method of the powder removal step is not particularly limited, but it is preferred to use a vibration screening machine to separate the fiber reinforced plastic crushed pieces sent to the next step from the powder.

[0092] As the heating method of the pyrolysis furnace in the pyrolysis treatment process, electric heaters, hot air, etc. can be cited. In the case of treating conductive reinforcing fibers such as carbon fibers, the hot air method is preferred. As the material handling method in the pyrolysis furnace, there are belt conveyor type, bucket conveyor type, and rotary furnace type in which the pyrolysis furnace itself rotates. Since the temperature in the pyrolysis furnace becomes high, the rotary furnace type without a conveyor is preferred from the viewpoint of equipment life.

[0093] The heat treatment temperature in the air atmosphere in the heat treatment process is preferably 300°C to 700°C. If the heat treatment temperature in the air atmosphere is 700°C or less, the resin H described later is likely to remain, and it is easy to become a state where the reinforcing fiber and the resin H coexist. As a result, the bundling of the reinforcing fiber bundle I is improved, and it is easy to remain as a bundling portion E after integrated molding, so the mechanical properties and dimensional accuracy are easy to improve. In addition, if the heat treatment temperature in the air atmosphere is 300°C or more, the resin H is reduced, the toughness as a matrix resin is easy to improve, and the mechanical properties are easy to improve.

[0094] The conveying method in the cooling and conveying step is not particularly limited, as long as the heat resistance is sufficient to convey the recycled reinforcing fiber thermal decomposition body in a high-temperature state immediately after thermal decomposition. The cooling method is also not particularly limited, and examples thereof include air cooling and natural cooling. Among them, natural cooling is preferred from the perspective of not requiring cooling equipment. In addition, it is also preferred that the conveying method be a belt conveyor type, a bucket conveyor type, etc., and natural cooling be performed during conveyance.

[0095] The classification method in the classification treatment step is not particularly limited, but a vibrating screen machine is preferred from the viewpoint of obtaining a recycled reinforcing fiber classification body of a desired size by changing the number of plates and the mesh size.

[0096] The iron removal method in the iron removal treatment process is not limited. It is preferred to set a device for removing metal powder by magnetic force in the piping through which the recycled reinforced fiber classification body passes, thereby recovering the iron powder generated during the treatment, or to separate it by using the difference in falling behavior caused by the presence or absence of magnetism when it passes near a magnet. Considering the processability, the long side of the obtained recycled fiber reinforced plastic is preferably 1 to 20 mm, more preferably 3 to 14 mm, and further preferably 5 to 8 mm. From the perspective of facilitating the improvement of operability, a sizing agent may also be added.

[0097] As another method for obtaining recycled fiber reinforced plastics, a method of cutting the fiber reinforced plastics into a desired size after heat treatment without crushing can also be cited. The heat treatment is preferably carried out in an oxygen-free atmosphere. The following heat treatment furnace is also preferably used in the heat treatment, wherein the heat treatment furnace comprises: a box-shaped main body; a heat treatment chamber arranged inside the aforementioned main body and accommodating the aforementioned fiber reinforced plastic; a combustion chamber arranged at the lower part of the aforementioned heat treatment chamber and equipped with a burner; and a heating chamber formed in the space between the aforementioned main body and the aforementioned heat treatment chamber, wherein the aforementioned fiber reinforced plastic is heat treated in the heat treatment chamber, and a part of the matrix component contained in the aforementioned fiber reinforced plastic is converted and attached to the surface of the aforementioned reinforcing fiber as the resin H described later. The heat treatment temperature in the oxygen-free atmosphere in the heat treatment chamber is preferably 200°C to 800°C. In addition, the aforementioned heat treatment furnace is equipped with a steam generator, which promotes convection in the heat treatment chamber by supplying water vapor at 100°C or more and 700°C or less to the heat treatment chamber, and can efficiently drive out the gas of the matrix component generated in the heat treatment chamber. It is possible to prevent in advance the generation of deposits on the floor and walls of the heating treatment chamber and the generation of tar in the piping due to the retention of the matrix component in the heating treatment chamber. Here, when the water vapor is heated to a temperature exceeding 700°C and supplied, it will cause a load on the heating treatment chamber and the piping, so it is not preferred. The obtained recycled reinforcing fiber is cut into a desired length using a known method such as a rotary cutter. Considering the processability, the long side is preferably 1 to 20 mm, more preferably 3 to 14 mm, and further preferably 5 to 8 mm. From the perspective of easily improving the operability, a sizing agent can be given.

[0098] The obtained recycled reinforcing fibers are also preferably subjected to iron removal treatment depending on the purpose.

[0099] Furthermore, as another method for obtaining recycled fiber reinforced plastics, waste flakes obtained by crushing and classifying fiber reinforced resin molded products are evenly spread on a metal plate, placed in an electric muffle furnace, and heat-treated while introducing nitrogen into the furnace and maintaining the treatment temperature at a predetermined temperature. Then, similarly, a method for obtaining recycled fiber reinforced plastics can be cited in which waste flakes are heat-treated while introducing air into the furnace and maintaining the treatment temperature at a predetermined temperature.

[0100] The heat treatment temperature in the air atmosphere in the heat treatment process is preferably 300°C to 700°C. If the heat treatment temperature in the air atmosphere is 700°C or less, the resin H described later is likely to remain, and it is easy to become a state where the reinforcing fiber and the resin H coexist. As a result, the bundling of the reinforcing fiber bundle I is improved, and it is easy to remain as a bundling portion E after integrated molding, so the mechanical properties and dimensional accuracy are easy to improve. In addition, if the heat treatment temperature in the air atmosphere is 300°C or more, the resin H is reduced, the toughness as a matrix resin is easy to improve, and the mechanical properties are easy to improve.

[0101] In addition, it is also a preferred method to perform the final heat treatment in an air atmosphere. In an inert nitrogen atmosphere, the resin H is unlikely to change even if the heat treatment is performed for a long time. By performing the final heat treatment in an active air atmosphere, a recycled fiber reinforced plastic having the desired resin H can be easily obtained.

[0102] As a crusher for fiber reinforced plastics, a shearing crusher, an impact crusher, a cutting crusher, a compression crusher, etc. can be cited. There is no problem in using any crusher, and a combination is also possible. In addition, as a classifier for crushed products, a vibrating screen machine, a rotary screen machine, a centrifugal screen machine, etc. can be cited. It is preferably used according to the crushing capacity of the crusher and the form of the crushed product.

[0103] The long side of the crushed recycled fiber-reinforced plastic is preferably 1 to 20 mm, more preferably 3 to 14 mm, and even more preferably 5 to 8 mm.

[0104] (Molding material mixture)

[0105] As long as the fiber-reinforced thermoplastic resin pellets F, the fiber bundle-reinforced thermoplastic resin pellets G and the thermoplastic resin D can be set to a predetermined mixing ratio according to the purpose, the method is not particularly limited, and the molding material mixture can be made by melt mixing, dry blending and other methods. Among them, dry blending is preferably used from the perspective of being able to easily adjust the content of the reinforcing fiber in the molded product. Here, the so-called dry blending, which is different from melt mixing, refers to stirring and mixing a variety of materials at a temperature where the resin component is not melted to form a substantially uniform state, and is mainly preferably used in the case of using pellet-shaped molding materials such as injection molding and extrusion molding. In order to achieve the target fiber content, thermoplastic resin pellets without reinforcing fibers can be mixed, and additives such as flame retardants can also be added according to the purpose.

[0106] (Electronic equipment housing member)

[0107] The electronic device housing component of the present invention has a thermoplastic resin component integrated with at least a portion of the peripheral region of the plate-like component. Here, the so-called integration means that the thermoplastic resin component or the plate-like component, or both, are melted and then cooled to bond. The peripheral region is the outer periphery of the plate-like component, but in order to improve the bonding strength with the thermoplastic resin component, it is also preferably integrated in a manner that a portion overlaps with the plate-like component.

[0108] In the component for electronic device housing of the present invention, in the thermoplastic resin component, a part of the reinforcing fiber A is dispersed in the form of monofilaments, and another part of the reinforcing fiber A is not dispersed in the form of monofilaments, but exists randomly in the form of a bundle E composed of multiple monofilaments. The number of monofilaments constituting the bundle E is preferably 2 or more, more preferably 5 or more, and more preferably 10 or more. The upper limit of the number of monofilaments constituting the bundle E is not particularly limited, preferably 100,000 or less, more preferably 80,000 or less, and more preferably 60,000 or less. If the number of monofilaments constituting the bundle E is 2 or more, the impact resistance of the obtained molded product when it falls can be improved. In addition, if the number of monofilaments constituting the bundle E is 100,000 or less, the fluidity during integrated molding is improved, and the filling property of the details is easily improved.

[0109] The length of the long side of the clustering portion E is preferably 0.5 to 20 mm, more preferably 0.8 to 15 mm, and further preferably 1.0 to 10 mm. If the length of the long side of the clustering portion E is 0.5 mm or more, the physical properties of the molded product are easily improved. In addition, if the length of the long side of the clustering portion E is 20 mm or less, the fluidity during integrated molding is improved, and the filling property of the fine parts is easily improved.

[0110] The length of the long side of the bundled portion E refers to the length of the longest single yarn among the single yarns constituting the bundled portion E. The bundled portion E may include single yarns shorter than 0.5 mm.

[0111] Here, the so-called random presence of the clustering portion E means that the clustering portion E is not aligned in a specific orientation. The acute angle side of the angle formed by the long side of the clustering portion E and the long side of other clustering portions E not in contact with the aforementioned clustering portion E is preferably 20° or more, more preferably 25° or more, and further preferably 30° or more. The angle of the clustering portion E can be measured by observing the cross section obtained by cutting the thermoplastic resin part at the desired position using an optical microscope. Among the angles formed by the lines obtained by extending the long sides of the observable clustering portion E and the other clustering portions E not in contact with it, it is preferred that at least one angle is 20° or more.

[0112] The reinforcing fibers A contained in the thermoplastic resin part are preferably discontinuous reinforcing fibers. Discontinuous reinforcing fibers are reinforcing fibers that are not continuous in one direction with a length of 100 mm or more, and a plurality of such fibers are arranged in different directions.

[0113] When a thermoplastic resin part is injection molded, the reinforcing fibers become shorter during the injection molding process, so the average fiber length of the reinforcing fibers in the molded product is usually shorter than the average fiber length in the pellet stage as the molding material. If the average fiber length of the reinforcing fibers in the molded product is too short, the impact resistance is reduced. In the case of being too long, the average fiber length of the molding material stage before injection molding also needs to be lengthened. If the average fiber length of the molding material stage is too long, the filling property of the details becomes insufficient. From this point of view, the average fiber length of the reinforcing fiber A in the molded product is preferably 10 μm to 20 mm, more preferably 12 μm to 15 mm, and further preferably 15 μm to 10 mm. If the average fiber length of the reinforcing fiber A is more than 10 μm, the physical properties of the molded product are easily improved. In addition, if the average fiber length of the reinforcing fiber A is less than 20 mm, the fluidity during integrated molding is improved, and the filling property of the details is easily improved.

[0114] In the component for electronic device housing of the present invention, the so-called bundling portion E refers to a portion in which the fiber directions are aligned and integrated without dispersion by a resin H different from the aforementioned thermoplastic resin D attached to the surface of the constituting monofilament. The so-called fiber direction alignment refers to a state in which most of the monofilaments constituting the bundling portion E point in the same direction. The angle offset between the monofilaments constituting the bundling portion E is preferably less than 20°, more preferably less than 10°, and further preferably less than 5°. When the angle offset between the monofilaments constituting the bundling portion E is less than 20°, the physical properties of the molded product are easily improved. The angles between the aforementioned monofilaments refer to: observing the bundling portion E with a microscope, etc., selecting any two monofilaments constituting the bundling portion E, and drawing lines along the length direction of the monofilaments, respectively, and the angles between the lines.

[0115] With respect to 100 parts by mass of the reinforcing fiber A contained in the bundled portion E, preferably 0.1 to 30 parts by mass of the resin H are attached, more preferably 3 to 20 parts by mass are attached, and further preferably 5 to 15 parts by mass are attached. If the content of the resin H is 0.1 parts by mass or more, the bundling property is improved, and the bundled portion E is easily formed, so the mechanical properties are easily improved. In addition, if the content of the resin H is 30 parts by mass or less, the dispersibility of the reinforcing fiber is improved, the fluidity during integrated molding is improved, the fine filling property is easily improved, and the appearance of the obtained molded product is easily improved.

[0116] The resin H is not particularly limited as long as it can bond the monofilaments of the reinforcing fibers to each other to form the bundled portion E. Unlike the resin J which does not have this function, examples thereof include a thermoplastic resin having a melting point sufficiently higher than the melting point of the surrounding thermoplastic resin D as the injection resin, a thermosetting resin, or a thermosetting resin that has been heat-treated as a recycle.

[0117] Examples of the thermoplastic resin include the resins exemplified as the aforementioned thermoplastic resin D. Examples of the thermosetting resin include the resins exemplified as the aforementioned plate-like member.

[0118] The resin H can be confirmed as a layer different from the surrounding resin D when observing the cross section formed by cutting the thermoplastic resin part through an optical microscope or the like. The resin H can be measured using the difference in melting point, solubility in solvent, etc. from the thermoplastic resin D. As an example of the measurement method, the reinforcing fiber A constituting the bundle E is a recycled fiber reinforced plastic obtained by taking out the CFRP containing epoxy resin and carbon fiber through any of the aforementioned heat treatments, and the thermoplastic resin D is a polycarbonate resin. However, as long as the measurement of the resin H can be performed after the bundle E is taken out from the thermoplastic resin D, the measurement method is not limited. Cut out the polycarbonate sheet to be measured from the molded product, put it in THF (tetrahydrofuran), and leave it for 24 hours. Take out the bundle E containing two or more carbon fibers separated from the polycarbonate with tweezers, and after sufficient drying, measure the weight K before heating. The bundle E whose weight has been measured is placed in an electric furnace capable of inhaling and exhausting nitrogen, and heated at 600°C for 3.5 hours in a nitrogen atmosphere to burn off the thermoplastic resin H, and then cooled to room temperature. The weight is then measured again to measure the weight after heating L. Here, the weight of the thermoplastic resin H = the weight before heating K - the weight after heating L. The method for measuring the thermoplastic resin H is also preferably: using a thermogravimetric-differential thermal analyzer (TG-DTA) according to the obtained sample amount; and performing the measurement according to the method described in JIS K7075.

[0119] The method for producing the electronic device casing member of the present invention is not particularly limited, and examples thereof include:

[0120] (i) A method of separately molding the plate-like member and the thermoplastic resin member in advance and joining the two together;

[0121] (ii) A method in which the plate-like member is molded in advance and the thermoplastic resin member is molded and the two are bonded simultaneously.

[0122] etc.

[0123] As a specific example of (i), a plate-like component is press-formed to produce a thermoplastic resin component by press-forming or injection molding, and a method in which the produced components are joined by known welding means such as hot plate welding, vibration welding, ultrasonic welding, laser welding, resistance welding, induction heating welding, etc. is cited.

[0124] On the other hand, as a specific example of (ii), the following method can be cited: a plate-like component obtained by press molding is arranged in an injection molding mold, a material forming a thermoplastic resin component is insert-injection-molded or externally-injection-molded in the mold, and the thermoplastic resin component as a molded body based on injection molding is joined to the plate-like component.

[0125] From the perspective of mass production of integrated molded products, method (ii) is preferred. In the injection molding of thermoplastic resin parts, the target shape can be formed in one step or multiple times. In order to reduce the deformation caused by curing shrinkage after molding, it is preferably implemented multiple times.

[0126] Hereinafter, as an example, a method of manufacturing the electronic device housing member of the present invention by integrating a plate-like member and a thermoplastic resin member by injection molding is described. However, the integration method can be selected according to the purpose and is not particularly limited as long as it is within the scope of the present invention.

[0127] The plate-like component is placed in an injection molding mold, and after the mold is closed, the molding material mixture prepared above is injection molded on the peripheral portion of the plate-like component to form an electronic device housing component having an integrated thermoplastic resin component. When the plate-like component is placed in the injection molding mold, it can be processed into a predetermined shape and size before use.

[0128] Example

[0129] Next, the present invention will be described using examples, but the present invention is not limited to these examples.

[0130] First, the evaluation method of the weight-average fiber length and the average single-filament diameter used in the present example will be described.

[0131] (1) Weight average fiber length (hereinafter sometimes referred to as average fiber length)

[0132] The test piece cut out from the molded product was put into a solvent in which the thermoplastic resin D and the resin H used in each example and comparative example are soluble, and a heating treatment was appropriately applied to obtain a solution in which the reinforcing fiber A is uniformly dispersed. Then, the solution was filtered using a quantitative filter paper (No. 5C) manufactured by ADVANTEC, and the reinforcing fiber A dispersed on the filter paper was observed using an optical microscope (50 to 200 times). The fiber lengths of 1,000 randomly selected reinforcing fibers A were measured, and the weight average fiber length (Lw) was calculated according to the following formula.

[0133] Average fiber length = Σ(Mi 2 ×Ni) / Σ(Mi×Ni)

[0134] Mi: Fiber length (mm)

[0135] Ni: The number of fibers with a fiber length of Mi.

[0136] (2) Average single-filament diameter (hereinafter sometimes referred to as single-filament diameter)

[0137] The test piece cut out from the molded product was put into a solvent in which the thermoplastic resin D and the resin H used in each example and comparative example are soluble, and a heating treatment was appropriately applied to obtain a solution in which the reinforcing fiber A is uniformly dispersed. Then, the solution was filtered using a quantitative filter paper (No. 5C) manufactured by ADVANTEC, and the reinforcing fiber A dispersed on the filter paper was observed using an optical microscope (50 to 200 times). The single fiber diameters of 1,000 randomly selected reinforcing fibers A were measured, and the average single fiber diameter was calculated according to the following formula.

[0138] Average single fiber diameter = Σ(Di) / Ni

[0139] Di: single wire diameter (mm)

[0140] Ni: The number of fibers with a single filament diameter of Di.

[0141] (Example 1)

[0142] (Method for forming plate-shaped parts)

[0143] Five layers of TORAYCA (registered trademark) carbon fiber unidirectional prepreg P3052S-15 (carbon fiber: T700SC-24K, 33% by mass of epoxy resin in 100% by mass of the prepreg, average filament diameter: 7.0 μm) manufactured by Toray Industries, Inc. were stacked. Regarding the stacking structure of the prepreg, when the longitudinal direction of the fiber-reinforced plastic molded product is set to 0°, the carbon fiber orientation is stacked in the order of 0° / 90° / 0° / 90° / 0° from the outermost layer. The component formed by sandwiching the stack with a release film is press-molded (mold temperature 150°C, pressure 1.5MPa, curing time 30 minutes, target thickness after pressurization 0.7mm) to obtain a plate-like component.

[0144] (Fiber-reinforced thermoplastic resin pellets F)

[0145] As the reinforcing fiber A, carbon fiber manufactured by Toray Industries, Inc. ("TORAYCA" (registered trademark) T700SC-24K, average single fiber diameter: 7.0 μm) was used.

[0146] A fiber-reinforced resin pellet manufacturing apparatus was used, in which a coating die for a wire resin coating method was provided at the tip of a TEX-30α twin-screw extruder (screw diameter 30 mm, L / D = 32) manufactured by Japan Steel Works, Ltd. The extruder barrel temperature was set to 230° C., and polycarbonate resin (Teijin Chemicals, Ltd., "Panlite" (registered trademark) L-1225L) was supplied from the main hopper as the thermoplastic resin D, and melt-kneaded at a screw speed of 200 rpm. The epoxy resin (Japan Epoxy Resin, Ltd., "jER828") heated and melted at 250° C. was adjusted in discharge amount to 6 parts by mass relative to 100 parts by mass of the total of the reinforcing fiber A and the thermoplastic resin D. Then, the aforementioned epoxy resin is ejected, impregnated and imparted to the fiber bundle containing the reinforcing fiber A, and then the fiber bundle of the reinforcing fiber A imparted with the aforementioned epoxy resin is supplied to the die (diameter 3mm) from which the molten polycarbonate resin is ejected, and is continuously arranged in a manner that the thermoplastic resin D covers the periphery of the reinforcing fiber A. In the internal cross-section of the fiber bundle at this time, at least a portion of the reinforcing fiber A is in contact with the thermoplastic resin D. After the obtained tow is cooled, it is cut into a pellet length of 7mm with a cutter to prepare a fiber-reinforced thermoplastic resin pellet F. At this time, the pulling speed is adjusted in a manner that the reinforcing fiber A becomes 30 parts by mass relative to the total of 100 parts by mass of the reinforcing fiber A and the thermoplastic resin D. The length of the reinforcing fiber A of the obtained fiber-reinforced thermoplastic resin pellet F is substantially the same as the pellet length, and the reinforcing fiber bundle is arranged parallel to the axial direction of the molding material.

[0147] (Fiber bundle reinforced thermoplastic resin pellets G)

[0148] A carbon fiber unidirectional prepreg ("TORAYCA" (registered trademark) prepreg) P3052S-15 (carbon fiber: T700SC-24K, containing 33% by mass of epoxy resin in 100% by mass of the prepreg, average single filament diameter: 7.0 μm) manufactured by Toray Industries, Ltd. was cured at 180°C for 2 hours to obtain CFRP. Then, 200 g of the aforementioned CFRP sheet, which had been crushed and classified so that the size of the long side was 5 to 8 mm by number average, was evenly spread on a metal plate, placed in an electric muffle furnace with an internal volume of 59 liters, and heat-treated for 5 hours in an oxidizing atmosphere while maintaining the treatment temperature at a predetermined temperature (550°C), to obtain a recycled carbon fiber bundle. A portion of the original resin adhered to the surface of the recycled carbon fiber bundle, resulting in a fiber bundle I with an average fiber length of 8 mm.

[0149] Next, a polycarbonate resin "Panlite" (registered trademark) L-1225L manufactured by Teijin Chemicals Co., Ltd. was supplied to the main hopper of a twin-screw extruder (TEX30α manufactured by The Japan Steel Works) as a thermoplastic resin D, and then the reinforcing fiber bundle I obtained above was supplied to the molten resin from the side feeder, and the screw speed was set to 200 rpm. The fiber bundle ejected from the die was cooled in water, cut into a length of 3.0 mm by a fiber bundle cutter, and pelletized to obtain fiber bundle reinforced thermoplastic resin pellets G. At this time, the amount of reinforcing fiber bundle I fed was adjusted so that the reinforcing fiber bundle I was 30 parts by mass relative to the total of 100 parts by mass of the thermoplastic resin D and the reinforcing fiber bundle I.

[0150] (Molding material mixture)

[0151] The fiber-reinforced thermoplastic resin pellets F and the fiber-bundle-reinforced thermoplastic resin pellets G obtained as described above were dry-blended so that the mass ratio of the reinforcing fibers A contained in the fiber-reinforced thermoplastic resin pellets F to the reinforcing fibers A contained in the fiber-bundle-reinforced thermoplastic resin pellets G was 70 / 30 to prepare a molding material mixture as an intermediate raw material.

[0152] (Integrated molding with thermoplastic resin parts)

[0153] The molded plate-like component was processed into a size of 318 mm×211 mm, placed in an injection molding mold, and after mold closing, the molding material mixture was injection molded into the peripheral edge of the plate-like component as a thermoplastic resin component to produce a composite molded product.

[0154] The injection molding mold used a mold having a shape of a rib with a width of 1 mm and a height of 5 mm formed on the finished molded product, and the aforementioned thermoplastic resin component was filled to the details. After the surface of the obtained thermoplastic resin component was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd., and the results showed that the reinforcing fibers A were dispersed in the entire thermoplastic resin component in the form of monofilaments, and a part of them existed as a bundle E of two or more monofilaments.

[0155] Then, as an evaluation of impact resistance, a 1 kg weight was attached to the composite molded product obtained above, and it was dropped from a height of 700 mm in such a way that the corner of the integrated thermoplastic resin part hit the ground first, but no cracks were generated. The average fiber length of the reinforcing fiber A contained in the obtained thermoplastic resin part was 0.3 mm.

[0156] (Example 2)

[0157] A carbon fiber prepreg ("TORAYCA" (registered trademark) prepreg) P2352W-19 (carbon fiber: T800SC-24K, containing 35% by mass of epoxy resin in 100% by mass of the prepreg, fiber diameter: 5.5 μm) manufactured by Toray Industries, Ltd. was cured at 180°C for 2 hours to obtain CFRP. Then, 200 g of the aforementioned CFRP sheet, which had been crushed and classified so that the size of the long side was 5 to 8 mm by number average, was evenly spread on a metal plate, placed in an electric muffle furnace with an internal volume of 59 liters, and heat-treated for 5 hours in an oxidizing atmosphere while maintaining the treatment temperature at a predetermined temperature (550°C) to obtain a recycled carbon fiber bundle. A portion of the original resin adhered to the surface of the recycled carbon fiber bundle to form a fiber bundle I with an average fiber length of 8 mm. A fiber bundle-reinforced thermoplastic resin pellet G was prepared using the fiber bundle I to prepare an injection molding material, and a composite molded product was prepared in the same manner as in Example 1.

[0158] The thermoplastic resin component of the composite molded article obtained above was filled into the details. As an evaluation of impact resistance, a 1 kg weight was attached and the integrated thermoplastic resin component was dropped from a height of 700 mm so that the corner of the component hit the ground first. No cracks were generated.

[0159] The surface of the obtained thermoplastic resin part was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., and then the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in the form of monofilaments throughout the thermoplastic resin part, and a portion thereof existed as a bundle E of two or more monofilaments. The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin part was 0.5 mm.

[0160] (Example 3)

[0161] When the fiber-reinforced thermoplastic resin pellets F and the fiber bundle-reinforced thermoplastic resin pellets G were dry-blended to produce a molding material mixture as an intermediate raw material, resin pellets formed from a thermoplastic resin D that did not contain reinforcing fibers A were added so that the reinforcing fiber content was 10% by mass in the entire 100% by mass molding material mixture, and a composite molded product was produced by the same method as in Example 1, except that the above-mentioned additions were sufficient to make the reinforcing fiber content 10% by mass in the entire 100% by mass molding material mixture.

[0162] The thermoplastic resin component of the composite molded article obtained above was filled into the details. As an evaluation of impact resistance, a 1 kg weight was attached and the integrated thermoplastic resin component was dropped from a height of 700 mm so that the corner of the component hit the ground first. No cracks were generated.

[0163] The surface of the obtained thermoplastic resin part was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., and then the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in the form of monofilaments throughout the thermoplastic resin part, and a portion thereof existed as a bundle E of two or more monofilaments. The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin part was 0.3 mm.

[0164] (Example 4)

[0165] As the skin material, two products were made by stacking two layers of carbon fiber unidirectional prepreg (UD PP) P3052S-15 (produced by Toray Industries, Ltd., using carbon fiber T700S, containing 33% by mass of epoxy resin in 100% by mass of the prepreg, average single fiber diameter: 7μm, thickness 0.12mm) in a manner orthogonal to the fiber arrangement direction. As the core material, a foamed material (EFSEL (registered trademark) RC2010, 2x foamed polypropylene, produced by Furukawa Electric Co., Ltd.) was prepared. The aforementioned foamed material was arranged as the core material, and in order to bond the core material to the skin material, an adhesive polyolefin nonwoven fabric (produced by Japan VILENE Co., Ltd., melting point 150°C, unit area weight 15g / m 2) are arranged above and below the core material, and then the core material is clamped by the aforementioned skin material to obtain a laminate. Furthermore, the laminate is press-formed (mold temperature 150°C, pressure 6MPa, curing time 30 minutes, target thickness after pressurization 1.5mm) to obtain a plate-like component. In addition, a composite molded product is prepared by the same method as in Example 1. Since the core material is included compared to Example 1, the deflection amount when a load is applied to the plate-like component is reduced while maintaining lightness.

[0166] The thermoplastic resin component of the composite molded article obtained above was filled into the details. As an evaluation of impact resistance, a 1 kg weight was attached and the integrated thermoplastic resin component was dropped from a height of 700 mm so that the corner of the component hit the ground first. No cracks were generated.

[0167] The surface of the obtained thermoplastic resin part was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., and then the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in the form of monofilaments throughout the thermoplastic resin part, and a portion thereof existed as a bundle E of two or more monofilaments. The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin part was 0.3 mm.

[0168] (Example 5)

[0169] A continuous carbon fiber bundle with a total number of 12,000 filaments was obtained by spinning and calcining a polymer mainly composed of polyacrylonitrile. A sizing agent was applied to the continuous carbon fiber bundle by an impregnation method and dried in heated air at a temperature of 120°C to obtain a PAN-based carbon fiber bundle. The PAN-based carbon fiber bundle was cut using a drum cutter to obtain a chopped carbon fiber bundle with a fiber length of 6 mm.

[0170] Furthermore, 100 liters of an aqueous solution of 1.5 parts by mass of a surfactant ("sodium n-dodecylbenzenesulfonate" (product name) manufactured by Wako Pure Chemical Industries, Ltd.) was stirred to prepare a pre-foamed dispersion. The chopped carbon fiber bundle obtained above was added to the dispersion, stirred for 10 minutes, and then flowed into a papermaking machine having a papermaking surface of 400 mm in length and 400 mm in width, dehydrated by suction, and then dried at a temperature of 150° C. for 2 hours to obtain a carbon fiber mat.

[0171] 90 parts by mass of unmodified polypropylene resin (Prime Polymer Co., Ltd., "Prime Polypro" (registered trademark) J105G, melting point 160°C) and 10 parts by mass of acid-modified polypropylene resin (Mitsui Chemicals, Inc., "ADMER" (registered trademark) QE510, melting point 160°C) were prepared and dry-blended. The dry-blended product was fed from the hopper of a twin-screw extruder, melt-kneaded by the extruder, and extruded from a 400 mm wide T-die. Then, the product was pulled by a chill roll at 60°C to cool and solidify, thereby producing two thermoplastic resin films.

[0172] As a skin material, two products were prepared by laminating two layers of carbon fiber unidirectional prepreg (UD PP) P3052S-12 (manufactured by Toray Industries, using carbon fiber T700S, containing 33% by mass of epoxy resin in 100% by mass of the prepreg, average single fiber diameter: 7 μm, thickness 0.12 mm) in a manner orthogonal to the fiber arrangement direction. The obtained thermoplastic resin film was arranged above and below the carbon fiber mat, and then sandwiched with the skin material to obtain a laminated body.

[0173] Next, the laminate is clamped with a release film and pressurized (mold temperature 180°C, pressure 3MPa, heating time 30 minutes, target thickness after pressurization 1.5mm), thereby solidifying the skin precursor to form a skin material, and softening the thermoplastic resin film, impregnating the carbon fiber mat to form a core layer precursor, so that the skin material and the core layer precursor are integrated. Then, the mold gap is enlarged by 0.7mm, and the core layer precursor is expanded by its restoring force to form a core layer with a gap. After 4 minutes, the mold is opened and quickly placed on the disk surface of a cooling pressurization mold with a disk surface temperature of 40°C, and cooled and pressurized at 3MPa. After 5 minutes, the molded product is taken out from the pressurization mold to obtain a sandwich structure with a plate thickness of 1.3mm, a skin layer thickness of 0.15mm, and a core layer thickness of 1.0mm. The sandwich structure is used as a plate-like component, and the same as Example 1 is used except for this. Since the core material is included compared to Example 1, the deflection amount when a load is applied to the plate-like member is reduced while maintaining lightness.

[0174] The thermoplastic resin component of the composite molded article obtained above was filled into the details. As an evaluation of impact resistance, a 1 kg weight was attached and the integrated thermoplastic resin component was dropped from a height of 700 mm so that the corner of the component hit the ground first. No cracks were generated.

[0175] The surface of the obtained thermoplastic resin part was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., and then the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in the form of monofilaments throughout the thermoplastic resin part, and a portion thereof existed as a bundle E of two or more monofilaments. The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin part was 0.3 mm.

[0176] (Comparative Example 1)

[0177] The same procedure as in Example 1 was carried out except that only the fiber-reinforced thermoplastic resin pellets F were prepared without mixing the fiber-bundle-reinforced thermoplastic resin pellets G.

[0178] A molding material mixture consisting only of the aforementioned fiber-reinforced thermoplastic resin pellets F was injection molded onto the peripheral edge of the aforementioned plate-like component in the same manner as in Example 1 to produce a composite molded product. As a result, no thermoplastic resin was present at the apex of the ribs, and there were areas where the thermoplastic resin was not filled into the details.

[0179] After the surface of the obtained thermoplastic resin part was polished using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in the form of monofilaments throughout the thermoplastic resin part, and no bundled portion E where two or more monofilaments were aggregated was observed.

[0180] Then, as an evaluation of impact resistance, a weight of 1 kg was attached to the composite molded product obtained above, and it was dropped from a height of 700 mm in such a way that the corner of the integrated thermoplastic resin component first hit the ground. As a result, no cracks were generated. The average fiber length of the reinforcing fiber A contained in the obtained thermoplastic resin component was 1.0 mm. Since the fiber bundle-reinforced thermoplastic resin pellets with excellent fluidity were not included, the filling property of the fine parts was reduced.

[0181] (Comparative Example 2)

[0182] A carbon fiber prepreg ("TORAYCA" (registered trademark) prepreg) P3052S-15 (carbon fiber: T700SC-24K, containing 33% by mass of epoxy resin in 100% by mass of the prepreg, average single filament diameter: 7 μm) manufactured by Toray Industries, Inc. was cured at 180°C for 2 hours to obtain CFRP. Then, the aforementioned CFRP sheet, which had been crushed and classified so that the size of the long side was 5 to 8 mm in number average, was prepared into a reinforcing fiber bundle I without heat treatment. The obtained reinforcing fiber bundle I was used to prepare a fiber bundle reinforced thermoplastic resin pellet G, and the fiber reinforced thermoplastic resin pellet F was not used. The same operation as in Example 1 was performed.

[0183] The thermoplastic resin component of the composite molded product obtained above was filled into the details, but part of it fell off during demolding. After grinding the surface of the obtained thermoplastic resin component using sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fiber A existed as a bundle E where two or more monofilaments were gathered, and the CFRP was not heated, so a large amount of resin H remained, and no reinforcing fiber A dispersed in a monofilament state was observed. In addition, a large number of areas where reinforcing fibers were not present were observed around the ribs.

[0184] Then, as an evaluation of impact resistance, a 1 kg weight was attached to the composite molded product obtained above, and it was dropped from a height of 700 mm in such a way that the corner of the integrated thermoplastic resin component first hit the ground. As a result, a crack of about 50 mm was generated in the thermoplastic resin component starting from the corner, and a part of the thermoplastic resin broke and fell off.

[0185] The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin part was 3.0 mm. Since the dispersion of the reinforcing fibers was insufficient, the region where the reinforcing fibers were absent increased, resulting in a decrease in impact resistance.

[0186] (Comparative Example 3)

[0187] A continuous carbon fiber bundle having a total filament number of 12,000 was obtained by spinning and calcining a polymer containing polyacrylonitrile as the main component. A sizing agent was applied to the continuous carbon fiber bundle by an impregnation method, and the bundle was dried in heated air at a temperature of 120° C. to obtain a PAN-based carbon fiber bundle. The PAN-based carbon fiber bundle was cut using a drum cutter to obtain a reinforcing fiber bundle I having a fiber length of 6 mm. The obtained reinforcing fiber bundle I was used to prepare a fiber bundle reinforced thermoplastic resin pellet G, and the fiber reinforced thermoplastic resin pellet F was not used. The same operation as in Example 1 was performed except that the fiber reinforced thermoplastic resin pellet F was not used.

[0188] The thermoplastic resin component of the composite molded article obtained above was filled into the fine parts. After the surface of the obtained thermoplastic resin component was polished with sandpaper 33-648 (P800) manufactured by Refinetec Co., Ltd., the surface was observed at a magnification of 150 times using a scanning electron microscope (SEM) JSM-6010LV manufactured by JEOL Ltd. As a result, the reinforcing fibers A were dispersed in a monofilament state, and no bundle E where two or more monofilaments were gathered was observed.

[0189] Then, as an evaluation of impact resistance, a 1 kg weight was attached to the composite molded product obtained above, and it was dropped from a height of 700 mm in such a way that the corner of the integrated thermoplastic resin component first hit the ground. As a result, cracks of about 10 mm were generated in the thermoplastic resin component starting from the corner.

[0190] The average fiber length of the reinforcing fibers A contained in the obtained thermoplastic resin component was 0.1 mm. As a result, there was no clustered portion E having a reinforcing effect, and the reinforcing fiber length was short and the impact resistance was reduced.

[0191] [Table 1]

[0192]

[0193] Industrial Applicability

[0194] The present invention can provide a thin-walled molded product for electronic equipment housing components having both strength and impact resistance, and can be widely used in components and housings of electrical and electronic equipment such as personal computers, OA equipment, AV equipment, and home appliances, but its application range is not limited to these.

[0195] Description of Reference Numerals

[0196] 1 Components for electronic equipment housings

[0197] 2 Plate-like parts

[0198] 3 Thermoplastic resin parts

[0199] 4 Cluster E

[0200] 5 Leather

[0201] 6 core material

[0202] 7Concave and convex shape (rib shape)

Claims

1. A component for an electronic device housing, comprising: Plate-like components having fiber-reinforced plastic; and a thermoplastic resin member integrated with at least a portion of the peripheral region of the plate-like member, The thermoplastic resin component comprises reinforcing fiber A and thermoplastic resin D, A portion of the reinforcing fibers A is dispersed in a monofilament form, The other part of the reinforcing fibers A is not dispersed in the form of monofilaments, but is randomly arranged in the form of a bundled portion E consisting of a plurality of monofilaments.

2. The electronic device housing member according to claim 1, wherein: The content of the reinforcing fiber A in the thermoplastic resin component is 1 to 50% by mass.

3. The electronic device housing member according to claim 1, wherein: On the surface of the monofilament constituting the bundled portion E, 0.1 to 30 parts by mass of a resin H different from the thermoplastic resin D is adhered to 100 parts by mass of the reinforcing fibers A contained in the bundled portion E.

4. The electronic device housing member according to claim 1, wherein: The average fiber diameter of single filaments in the reinforcing fibers A of the thermoplastic resin component is 4.0 to 30.0 μm.

5. The electronic device housing member according to claim 1, wherein: The plate-shaped member is a sandwich structure formed of a core material and fiber reinforced plastics bonded to both surfaces of the core material.

6. The electronic device housing member according to claim 1, wherein: The reinforcing fiber A includes two reinforcing fibers, a reinforcing fiber B and a reinforcing fiber C, which have different average fiber diameters of single fibers. The reinforcing fibers B do not form the bundled portion E. A portion of the reinforcing fibers C are dispersed in a monofilament form. Another part of the reinforcing fibers C constitutes the bundled portion E.

7. The electronic device housing member according to claim 6, wherein: The mass ratio B / C of the reinforcing fiber B to the reinforcing fiber C is 99 / 1 to 40 / 60.

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