JP2008266648A - Fiber reinforced thermoplastic resin composite material and formed article using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber reinforced thermoplastic resin composite material which is light in weight and also high in strength, is excellent in heat-resistance, wear resistance and impact resistance, has excellent impregnating ability and small void, and excellent in formability and recyclability, and a formed article using it. <P>SOLUTION: The composite material using a para aramide fiber as a reinforcing material and a thermoplastic resin as a matrix is obtained by heating compression molding of a braid which contains the para aramide fiber as a core yarn and a thermoplastic resin fiber as a braid yarn, or a laminate of the braid with a thermoplastic resin film or nonwoven fabric. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fiber-reinforced thermoplastic resin composite material using a para-aramid fiber as a reinforcing material and a thermoplastic resin as a matrix, and a molded body using the composite material.

  Plastic composite materials composed of fiber reinforcements and matrix resins are lighter, more diverse, and have made remarkable progress compared to metal composite materials and ceramic composite materials. Used as machined parts, precision machinery, electrical / electronic equipment, building materials, vehicle parts / members, office automation equipment, AV equipment, daily goods, sports equipment, medical equipment, aircraft, space equipment parts / members, etc. Has been.

  As the reinforcing fibers of the plastic composite material, inorganic fibers such as glass fibers and carbon fibers and organic fibers such as aramid fibers are mainly used from the viewpoint of high strength, high elastic modulus and excellent heat resistance. Organic fibers have low specific gravity and light weight, and para-aramid fibers have characteristics such as heat resistance, dimensional stability, and chemical resistance in addition to the mechanical properties of high strength and high elasticity among synthetic fibers. Therefore, it is used as a reinforcing material for plastic composite materials.

  On the other hand, the matrix resin has excellent properties such as high strength, high elastic modulus, elongation at break, mechanical and environmental durability, and good affinity with reinforcing materials. It is required that the moldability is excellent. As the matrix resin, thermosetting resins such as epoxy resins and unsaturated polyester resins are widely used. Good moldability and adhesion to reinforcing fibers, and excellent mechanical properties, heat resistance, chemical resistance, etc. Yes. However, the problem with thermosetting resins is that because of the curing life of the resin, there is a limit to the time that it can be used and working, and because it involves a curing reaction, the molding time is long, and unlike thermoplastic resins, it is melted again and processed. Is that you can't. Therefore, it uses a thermoplastic resin that has better moldability and impact resistance than thermosetting resins, and is excellent in fatigue, heat resistance, chemical resistance, etc., and can be remelted after use. High performance composite materials using a thermoplastic resin as a matrix have been put into practical use.

  Unlike the thermosetting resin, the production of the thermoplastic resin composite material is completed by steps of heating and melting without accompanying a curing reaction, pressurizing and compressing, shaping, and cooling. However, the following method has also been proposed. That is, a prepreg is made by a method such as impregnating a resin into a reinforcing fiber or attaching resin powder, and the matrix resin is softened or melted by heating the prepreg using a mold or the like, and simultaneously compressed and compressed. Then, it is shaped into a predetermined shape and cooled and solidified.

  Specific methods include (1) a method in which a resin is heated and melted and impregnated into the fiber (melt impregnation method), and (2) a method in which the resin is powdered and applied to the fiber by a fluidized bed method or a suspension method ( (Powder method), (3) There are methods such as (3) making resin into solution and removing the solvent after impregnating the fiber (solution impregnation method), and (a) shaping and cooling using a mold Solidification method (die press method), (b) Method using vacuum forming of thermoplastic resin sheet (vacuum forming), (c) Method of heating, pressurizing, shaping and cooling material in autoclave (autoclave There are various methods such as (molding), (d) impregnated and dried reinforcing materials and prepreg sheets that are wound around a mandrel while being heated and melted, fused, and cooled (prepreg sheet winding method).

  For example, Japanese Patent Laid-Open No. 60-34690 proposes a method of manufacturing a pultruded product by adhering or impregnating a powder or aqueous slurry of polyarylene sulfide to a fiber strand made of glass fiber or carbon fiber. (See Patent Document 1). Similarly, JP-A-3-46010 discloses a hybrid yarn composed of continuous single fibers of polyarylene sulfide and continuous single fibers of carbon fibers coated with epoxy sizing, and weaves this to produce a prepreg. There has been proposed a method for producing a composite sheet having a carbon fiber content of about 60% by pressurizing it at a temperature equal to or higher than the melting point of polyarylene sulfide in a pressure range of 0.35 MPa to 1.4 MPa (Patent Document). 2).

  Further, in JP-A-6-256534, in obtaining a composite material composed of reinforcing fibers and polyphenylene sulfide (hereinafter referred to as PPS), after impregnating the reinforcing fibers in a molten state with PPS by the following method, By rapidly cooling in the molding cooling process to form a composite material using amorphous PPS as a matrix, and then heat-treating the composite material at a temperature higher than the crystallization temperature of PPS, all of heat resistance, strength and wear resistance are obtained. Has disclosed a method for producing a composite material excellent in (see Patent Document 3). That is, a fiber reinforced resin sheet is formed by laminating a plurality of glass fiber plain weave cloths in different directions and further heat-pressing a material obtained by laminating a PPS film with a hot press molding machine.

  However, the above technique relates to a composite material in which PPS resin is impregnated with inorganic fibers such as glass fibers or carbon fibers, and when applied to organic fibers such as aramid fibers, the adhesion between the fibers and the thermoplastic resin. Depending on the quality, there is a problem that the adhesiveness is lowered or cracks are likely to occur because sufficient durability cannot be obtained. Also, the adhesive strength may be weak due to the affinity problem between the fiber and the thermoplastic resin. When the fiber is not sufficiently impregnated with resin, the unimpregnated portion becomes a void.

  Further, JP-A-7-300072 (Patent No. 3401318) discloses a composite material obtained by impregnating a mesh sheet with a nylon-based resin by spraying a nylon-based resin on a mesh sheet made of a filamentous glass fiber. Is manufactured by rolling and rolling it into a cylindrical shape, and there is disclosed a lighter and flexible crossing barrier device for a crossing barrier (see Patent Document 4). However, when this method is applied to organic fibers such as aramid fibers, it is necessary to devise a technique for improving the adhesion between the organic fibers and the resin and increasing the impregnation property. In view of the above circumstances, various proposals have been made regarding the production of composite materials in which an organic fiber reinforcing material, which has relatively poor adhesion to a thermoplastic resin, is combined with a thermoplastic matrix resin.

  For example, Japanese Patent Application Laid-Open No. 62-135565 discloses a composite material of an aramid fiber and a polyether ether ketone resin (see Patent Document 5). The aramid fiber wound around the bobbin is continuously passed through the solvent solution of the polyethersulfone resin, and after drying, the fiber bundle is separated from the mandrel into a sheet that is aligned in one direction, and this is alternated with the polyetheretherketone film. The fiber reinforced composite material is manufactured by laminating the laminate and hot pressing the laminate. However, in this method, since aramid fibers are pre-treated in advance and wound around a mandrel, a number of steps similar to the production of a conventional thermosetting resin composite material are required.

  JP-A-7-238174 discloses a fiber-reinforced composite material in which aramid fibers are embedded in a thermoplastic resin (see Patent Document 6). When a laminate of unidirectionally aligned tow materials composed of a thermoplastic amorphous polyamide copolymer based on para-aramid filaments and bis (para-amino-cyclohexyl) methane is hot-pressed, an aramid is interposed between the laminates. By inserting a porous material such as fiber spunlace nonwoven fabric, the movement of the unidirectional reinforcing fiber and the fiber displacement due to compression are reduced, the fiber alignment is increased, and the transverse and longitudinal strength and elastic modulus of the composite material are increased. It is improved. However, although this method improves the mechanical properties in the lateral direction to some extent, a satisfactory composite material has not yet been obtained.

As described above, various proposals have been made regarding composite materials composed of organic fibers and a thermoplastic resin matrix, but the affinity or adhesion between the fibers and the resin is good, the impregnation property is good, and voids can be suppressed. At the same time, a composite material of a thermoplastic resin having excellent impact resistance, heat resistance, wear resistance, and resin recyclability and excellent molding processability has not been obtained.
JP-A-60-34690 Japanese Patent Laid-Open No. 3-46010 JP-A-6-256534 Japanese Patent Laid-Open No. 7-300072 Japanese Patent Laid-Open No. Sho 62-135565 JP-A-7-238174

  The present invention is a fiber-reinforced thermoplastic resin that is lightweight, has high strength and high elastic modulus, is excellent in heat resistance, wear resistance, and impact resistance, has good impregnation properties, has few voids, and has excellent moldability and recyclability. An object is to provide a composite material and a molded body using the composite material.

  As a result of intensive studies to achieve the above object, the present inventors have found that a composite material in which organic fibers and thermoplastic resins having high strength and excellent heat resistance and wear resistance are integrated by heat compression is heat resistant. The present invention has been completed by finding that it has excellent heat resistance, wear resistance and impact resistance, and that voids are suppressed.

  That is, the present invention is a composite material having a para-aramid fiber as a reinforcing material and a thermoplastic resin as a matrix, the braid having the para-aramid fiber as a core yarn and the thermoplastic resin fiber as a braid, or the braid The present invention provides a composite material obtained by heat compression molding a laminate of a thermoplastic resin film or a nonwoven fabric.

  In the composite material, the para-aramid fiber is more preferably polyparaphenylene terephthalamide fiber. The para-aramid fiber may be one in which a film former, a silane coupling agent, and a surfactant are provided on the fiber surface and inside the fiber.

  In the composite material of the present invention, the thermoplastic resin is polyester resin, polyamide resin, polyoxymethylene resin, polycarbonate resin, polyphenylene sulfide resin, modified polyphenylene ether resin, polyetherimide resin, polysulfone resin, polyethersulfone. At least one selected from resin, polyketone resin, polyarylate resin, polyether nitrile resin, polyether ketone resin, polyether ether ketone resin, polyether ketone ketone resin, polyimide resin, polyamideimide resin, fluororesin and liquid crystal polymer resin Preferably there is.

  In the present invention, the composite material may have a pellet form.

  Furthermore, this invention provides the molded object characterized by shape | molding the said composite material.

  The molded body of the present invention includes reinforcing, friction / sliding, automobile, marine and other industrial machinery elements, electrical / electronic equipment, AV equipment, OA equipment, building parts / members, building materials and fittings, packings, etc. Or it is used suitably for seals.

  As described above, according to the present invention, it is possible to obtain a composite material that is lightweight, excellent in heat resistance, wear resistance, impact resistance, impregnation of fibers and thermoplastic resin, and suppressed in voids. Can do. In addition, the composite material has excellent working environment characteristics because it does not use a solvent during molding, and is excellent in moldability because it is thermoplastic, and is excellent in recyclability because it can be reused by heating and melting. . Therefore, by using the composite material, it is possible to easily obtain a molded body excellent in heat resistance, wear resistance, impact resistance and durability, and to be an environmentally friendly molded body that can be easily recycled. .

  The composite material of the present invention is a composite material having a para-aramid fiber as a reinforcing material and a thermoplastic resin as a matrix, the braid having the para-aramid fiber and the thermoplastic resin fiber as constituent materials, or the braid and the heat The laminate is not particularly limited as long as the laminate of the plastic resin film or the nonwoven fabric is integrated by pressure compression molding under heating.

  The para-aramid fiber used as the reinforcing material used in the present invention is not particularly limited as long as it can exhibit desired strength, elastic modulus and the like according to the purpose. Para system aramid fiber may be used independently and may be used in combination of 2 or more types as appropriate.

  From the viewpoint of use as a reinforcing fiber, it is preferable that at least a part thereof includes a para-aramid fiber having a tensile strength of 7.5 cN / dtex or more, preferably 15 cN / dtex or more. The fiber having a tensile strength of 15 cN / dtex or more is preferably 50% by mass or more, more preferably 100% by mass, based on the whole para-aramid fiber. If the tensile strength of the para-aramid fiber is 15 cN / dtex or more, it becomes 7.5 cN / dtex or more when 50% by mass is used. The tensile strength of the para-aramid fiber is particularly preferably within the range of 15 to 48 cN / dtex. In addition, "tensile strength" is calculated | required by measuring according to JIS L1013 (1999) chemical fiber filament yarn test method 8.5.1.

  It is more preferable that the para-aramid fiber has the above strength and has a tensile elastic modulus of 440 to 3,000 cN / dtex. If the tensile modulus is 440 cN / dtex or more, sufficient characteristics as a belt material can be imparted when applied as, for example, a tire reinforcing material. The tensile elastic modulus is particularly preferably in the range of 440 to 2,500 cN / dtex.

  The fineness of the para-aramid fiber is not particularly limited, but usually 50 to 10,000 dtex is used. Preferably it is 200-6,500 dtex, More preferably, it is 750-3,500 dtex. The smaller the fineness of the para-aramid fiber, the thinner the braid and the thin fabric, and the greater the fineness, the thicker braid and the thick fabric.

  The para-aramid fiber used in the present invention is appropriately selected according to the use of the final product, required performance, fiber manufacturing cost, product processing cost, and the like.

  Aramid fibers include para-aramid fibers and meta-aramid fibers. Para-aramid fibers that have low heat shrinkage, high heat resistance, and high strength are particularly preferable. Examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (manufactured by DuPont, Inc., Toray DuPont, trade name “KEVLAR” (registered trademark)), copolyparaphenylene-3,4′-oxydi. Commercial products such as phenylene terephthalamide fiber (manufactured by Teijin Techno Products Limited, trade name “Technola” (registered trademark)) can be used. Examples of the meta-aramid fiber include polymetaphenylene terephthalamide fiber (made by DuPont, USA, trade name “NOMEX” (registered trademark)). In addition, you may use the above-mentioned aramid fiber manufactured by the well-known method or the method according to it.

  As the aramid fiber, those having a film former, a silane coupling agent and a surfactant added to the fiber surface and inside the fiber can also be used. By using the aramid fiber, adhesion is improved as well as adhesion, and voids are suppressed, and the strength, durability, impact resistance, and the like of the composite material are improved. The solid content of the surface treatment agent on the aramid fiber is preferably in the range of 0.01 to 20% by mass.

  Here, as the film former, a highly functional film former such as urethane type and epoxy type used as a fiber surface treatment agent for composite materials, a starch type, a polyvinyl alcohol type, an acrylic type film former, etc. And emulsion type oligomers dispersed in water.

  As the silane coupling agent, conventionally used aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane, glycidylpropyltriethoxysilane, methacryloxypropyltrimethoxysilane, vinyltriethoxysilane and the following general formulas ( The compound etc. which are shown by 1) are mentioned.

R ₁ —Si— (OR ₂ ) ₃ (1)
R _{1 in the} formula (1) is an organic group that reacts or has a strong interaction with the resin, and R ₂ is an alkyl group having 1 to 4 carbon atoms.

  As said surfactant, what makes said silane coupling agent and a film former permeate | transmit into a crystalline fiber structure is used. In particular, a cationic surfactant is desirable, and examples thereof include dimethylaminopropyl alkydamide diethyl sulfate.

  The thermoplastic resin used as the matrix used in the present invention may be any resin as long as it is not cured by heating, and is not particularly limited in the present invention. For example, polyolefin resins such as polyethylene resin, polypropylene resin, and polybutylene resin; methacrylic resins such as polymethyl methacrylate resin; polystyrene resins such as polystyrene resin, ABS resin, and AS resin; polyethylene terephthalate (PET) resin, polybutylene terephthalate Polyester resins such as (PBT) resin, polytrimethylene terephthalate resin, polyethylene naphthalate (PEN) resin, poly 1,4-cyclohexyldimethylene terephthalate (PCT) resin; 6-nylon resin, 6,6-nylon resin, etc. Polyamide (PA) resin; polyvinyl chloride resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, modified polyphenylene ether PPE) resin, polyetherimide (PEI) resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, polyketone resin, polyarylate (PAR) resin, polyethernitrile (PEN) resin, polyetherketone (PEK) Resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyimide (PI) resin, polyamideimide (PAI) resin, fluorine (F) resin; liquid crystal polymer resin such as liquid crystal polyester resin; polystyrene series , Thermoplastic elastomers such as polyolefins, polyurethanes, polyesters, polyamides, polybutadienes, polyisoprenes or fluorines; or their copolymer resins and modified resins.

  Among them, polyester (PET, PBT, PCT) resin, polyamide (PA) resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, modified polyphenylene ether (PPE) resin, polyether Imide (PEI) resin, Polysulfone (PS) resin, Polyethersulfone (PES) resin, Polyketone resin, Polyarylate (PAR) resin, Polyethernitrile (PEN) resin, Polyetherketone (PEK) resin, Polyetheretherketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyimide (PI) resin, polyamideimide (PAI) resin, fluorine (F) resin, and liquid crystal polymer resin are preferred.

  In the present invention, the thermoplastic resin is particularly preferably one that is widely used as an engineer plastic, and nylon resin, polyacetal resin, polyphenylene sulfide resin, polyether ether ketone resin, and polyether ketone ketone resin are suitable. Polypropylene resins and polyester (PET) resins that are inexpensive and have good recyclability are also preferably used.

  The thermoplastic resin fiber used in the present invention is not limited as long as it is produced from the thermoplastic resin used as a matrix. For example, a fiber produced according to a known method such as wet spinning, dry spinning or melt spinning. Can be used. The thermoplastic resin fibers may be used alone or in combination of two or more. The fineness is not particularly limited, but usually 50 to 10,000 dtex is used. Preferably it is 200-6,500 dtex, More preferably, it is 750-3,500 dtex. In addition, recycled products from raw yarns, raw cottons, and fiber products thereof, and recycled products using waste generated in the processing process can also be used.

  The thermoplastic resin film is not limited as long as it is produced from the above-mentioned thermoplastic resin, and it is preferable that films having various thicknesses can be prepared in order to control the resin amount. Moreover, any of a stretched film, a uniaxially oriented film or a biaxially oriented film, an unstretched film, and an unoriented film may be used.

  The thickness of the thermoplastic resin film is not particularly limited, and is appropriately determined according to the type of organic fiber or thermoplastic resin and the required characteristics of the material to be designed. Usually, the thing of 30 micrometers-500 micrometers is used suitably.

  The composite material of the present invention comprises the para-aramid fiber and the thermoplastic matrix resin, and the proportion of the para-aramid fiber in the composite material varies depending on the required performance of the final product, the manufacturing cost of the material, and the like. The content of the para-aramid fiber relative to the entire composite material is suitably in the range of 5 to 80% by weight, preferably 5 to 70%.

  Next, the manufacturing method of the composite material of this invention is demonstrated.

  The composite material of the present invention comprises the above-described para-aramid fiber and a thermoplastic matrix resin, and heat-compresses a braid composed of the para-aramid fiber and the thermoplastic resin fiber or a combination thereof. Can be manufactured by integrating them. As the braid, a braid produced by a conventionally known method can be appropriately used. It can also be produced by forming a laminate of a braid and the above thermoplastic resin film or non-woven fabric, and heating and compressing the laminate.

  In the case of producing a composite material, the production conditions are not particularly limited as long as the composite material can be produced. However, a braid composed of para-aramid fibers and thermoplastic resin fibers or a combination thereof is heated. It is better to press and mold them underneath. For example, (A) a method in which a braid composed of para-aramid fibers and thermoplastic resin fibers is pressure-formed under heating, (B) a braid composed of para-aramid fibers and thermoplastic resin fibers, and a thermoplastic resin film Or the method etc. which press-mold a laminated body with a nonwoven fabric under heating can be mentioned. In this case, the resin constituting the thermoplastic resin film or the nonwoven fabric may be the same or different from the resin constituting the thermoplastic resin fiber that is the matrix resin, but the same kind of resin is preferred.

  As a heating method in the heat compression, for example, a known method such as a heater can be appropriately used. The heating temperature is preferably equal to or higher than the melting temperature of the thermoplastic resin. By heating for a certain period of time above the melting temperature of the thermoplastic resin, the thermoplastic resin melts between the fibers of the para-aramid fiber, and by compressing this, the para-aramid fiber is pushed into the thermoplastic resin. A composite material that is well impregnated and has almost no unimpregnated area is easily formed. The heating temperature is more preferably within the range of about 80 ° C to 350 ° C. When the heating temperature is too low, the melt viscosity of the thermoplastic resin fiber or the like is high, so that impregnation is insufficient. On the other hand, when the heating temperature is too high, the resin may flow out and gas may be generated. When the composite material is produced by the above method (A), it is particularly preferable that the temperature is within a temperature range suitable for molding a pre-processed material such as a prepreg. When the composite is produced by the method (B), it is particularly preferable that the temperature is within a temperature range in which a flat plate material can be formed by press forming.

  Moreover, as a pressurization method, well-known methods, such as a vapor pressure, a pneumatic pressure, or a hydraulic pressure, can be used suitably, for example. The pressurizing pressure is preferably in the range of about 0.1 to 200 MPa, and more preferably in the range of 0.5 to 100 MPa. When the pressure at the time of heat compression is too low, the impregnation property is poor and the number of unimpregnated parts increases. On the other hand, if the pressure during heating and compression is too high, the resin to be impregnated flows out and adversely affects the quality of the composite material. In the case of the method (A), it is particularly preferably in the range of 0.5 to 100 MPa, and in the case of the method (B), it is particularly preferably in the range of 5 to 100 MPa.

  In the present invention, the heat compression time is not particularly limited, and molding can be performed in the range of several minutes to several hours. However, it is preferable that the molding cycle is as short as possible because productivity is improved.

  The composite material of the present invention produced by the above-described method or the like may be a solid, semi-solid or viscous material, and the form is not particularly limited, but is usually a solid or semi-solid. The solid form is more preferably a fiber bundle, string or sheet.

  The composite material of the present invention thus obtained makes the thermoplastic resin material high strength and high elastic modulus. The characteristics differ depending on the type of organic fiber and matrix thermoplastic resin used, the ratio of use thereof, the shape of the molded body, and the like. It is preferable that the number of voids is as small as possible (the non-impregnated region is 3% or less), and the impregnation rate is 90% or more to become a composite material.

  In the case of a film-like or sheet-like composite material, it is better to prepare a molded body if an appropriate thickness level is prepared.

  Hereinafter, the method (A) will be described in more detail. In this method, the composite material of the present invention is manufactured by arranging braids composed of para-aramid fibers and a thermoplastic resin in parallel and then compressing them by heating. The “braid” is a braid composed of a para-aramid fiber and a thermoplastic resin fiber, and uses a para-aramid fiber as a core yarn and a thermoplastic fiber as a braid. A preferable production method using braid includes, for example, a method in which a para-aramid fiber is used as a core yarn and the periphery of the core yarn is braided with a plurality of thermoplastic resin fibers. Depending on the density of braiding and the fiber content, for example, 4-, 8-, 12-, or 16-piece assemblies may be used. In the case of braiding, it is preferable to use a known braiding machine. For example, a four-piece braid is prepared by preparing four yarns and alternately arranging right and left yarns in the middle.

  As shown in FIG. 1, a braid structure in which a para-aramid fiber is used as a core yarn and a thermoplastic resin fiber is braided has a para-aramid fiber 1 inserted in one direction as a core yarn, and a thermoplastic resin fiber on the outside thereof. 2 is a structure assembled as a braid.

  The heating and pressurization in the “heating and compressing step” may be performed using the above-described methods, conditions, and the like. For example, as shown in a cross-sectional view in FIG. 8, impregnation is performed by a method in which braided cords 11 having a plurality of core yarns arranged in parallel in a mold 12 are stacked and heated, melted, and sequentially pressed in the cooling process. And eliminate the unimpregnated area. After the heat compression step, the thermoplastic resin can be completely solidified by taking out from the mold and cooling. The cooling method is not particularly limited, and may be a known method such as a method using a medium such as water, ice, ice water, dry ice, liquid nitrogen, or ordinary cooling. Cooling is performed as necessary. The drying method is not particularly limited, and can be performed by a known means such as an oven dryer. In the present invention, it is more preferable to pressurize for a certain time even during cooling. The pressure condition for pressurization is about 50 MPa or less, and in press molding, it is more preferably in the range of about 0.1 to 10 MPa, which is about the contact pressure.

  Hereinafter, the method (B) will be described in more detail. In this method, the composite material of the present invention is produced by heat-compressing a laminate of a braid composed of para-aramid fibers and thermoplastic resin fibers and a thermoplastic resin film.

  The “heating and compressing step” can be performed under the above-described conditions in the same manner as in the method (A). For example, as shown in a cross-sectional view in FIG. 9, a bundle 4 of braids made of para-aramid fibers and thermoplastic resin fibers are arranged in parallel in the mold 12, and the thermoplastic resin film 3 is stacked thereon, (A) The method of shape | molding similarly to having described by the method is mentioned. It is good also as a multilayer laminated body, and the number of lamination | stacking is not limited. The resin impregnation rate is selected according to the required performance of the composite material to be designed. The cooling in this method may be a method similar to the above method (A), but is preferably allowed to cool at room temperature (−5 ° C. to 40 ° C.).

  In the present invention, various additives and modifiers may be blended in the thermoplastic resin as long as the object of the present invention is not impaired. Examples of the additives include heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, organic lubricants such as pigments, dyes, fatty acid esters, and waxes. Moreover, you may contain surfactant. In addition, a compatibilizing agent may be blended in order to enhance the adhesion between the para-aramid fiber and the thermoplastic resin as long as the object of the present invention is not impaired. In addition, various fillers can be blended in the composite material as desired to give desired characteristics.

  The molded body in the present invention is not particularly limited as long as it is obtained by molding a molding material containing at least the composite material of the present invention by a known method. For example, a molding material obtained by kneading the same pellet as a thermoplastic resin fiber into a molded body obtained by molding a composite material into a desired shape using a known method such as cutting, or a master pellet obtained by cutting a composite material, Examples include a molded body formed using a known method and apparatus such as extrusion molding and injection molding.

  When the composite material is cut, for example, pellets are preferably cut and pulverized using a cutting machine or a pulverizer equipped with a pelletizer, a cutter, or the like so as to have a desired size.

  The composite material of the present invention can be formed into various molded products by applying a known method or the like. The molded body of the composite material of the present invention can be used as a reinforcing material for all applications that require heat resistance, wear resistance, and impact resistance. For example, mechanical element parts such as plates, bearings, gears, cams, pipes, bars, bushes, washers, guides, pulleys, facings, insulators, rods, bearing retainers, etc., electrical and electronic parts such as connectors, plugs, arms, AV / OA equipment parts such as sockets, caps, rotors, motor parts, etc. Speaker cones, housings, bearings, rods, guides, gears, etc., building parts and materials, stoppers for construction equipment and building materials, guides, doors, angles In addition, helmets, plastic model parts, core materials for tires, reel parts for fishing gear, seals, packings, gland packings, and the like can be given.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example, this invention is not limited only to a following example.

Example 1
Para-aramid fibers (KEVLAR 29 (registered trademark), 1670 dtex, manufactured by Toray DuPont Co., Ltd.) were used as the high-strength organic fibers. Further, a polyamide 66 resin fiber bundle (470 dtex, manufactured by Toray Industries, Inc.) was used as the thermoplastic resin fiber. An aramid fiber bundle is used as a core material, and a polyamide 66 resin fiber bundle is braided by a 16-pipe tubular braiding machine on the outside of the aramid fiber bundle, and the braid is made of aramid fibers and the braid is made of polyamide 66 resin fibers. Got. The ratio (volume ratio) between the aramid fiber and the polyamide 66 resin fiber of this braid is 42:58.

  The obtained fiber bundle-shaped material was wound around a metal frame in one direction and heated and compressed by a press molding machine using a mold to obtain a composite material flat plate. The heat compression conditions were a pressure of 4 MPa, a temperature of 290 ° C., and a heat compression time of 5, 10, 20, and 40 minutes, respectively. After the heat compression, the unidirectional composite material flat plate obtained above was cooled and fixed with ice water while applying a certain pressure to the mold.

  FIG. 2 shows the results of the resin impregnation rate (ratio of the impregnated region containing thermoplastic fibers in the fiber yarn bundle) according to the heat compression time. As the time increased, the resin impregnation rate into the aramid fibers improved, and good impregnation was obtained in about 20 minutes under the present production conditions. Incidentally, the resin impregnation rate was 61% at 5 minutes of heating and compression time, 69% at 10 minutes, 89% at 20 minutes, and 94% at 40 minutes.

(Tensile properties)
A test piece having a width of 20 mm, a length of 180 mm, and a thickness of 1.1 to 1.3 mm was prepared so that the fiber axis direction was the test piece longitudinal direction. Using a universal testing machine manufactured by Instron, the tensile modulus and tensile strength were determined at a displacement speed of 1 mm / min, a distance between gauge points of 80 mm, and room temperature. The results are shown in FIG.

  The material subjected to tensile properties has a flat fiber volume impregnation rate (Vf) as shown in the following table (Table 1), and the level of the normal composite material is reached in about 5 minutes. It became a tendency to be washed away. As shown in FIG. 3, both strength and elastic modulus were the highest under heating and compression conditions of about 10 minutes. It is considered that the flow of fibers is caused along with the flow of resin by heating and pressing for 10 minutes or more, and the physical properties are lowered.

(Bending characteristics)
The three-point bending test piece was prepared such that the fiber axis direction (0 ° direction) and the direction perpendicular to the fiber axis direction (90 ° direction) were the test piece longitudinal direction. Using a universal testing machine manufactured by Instron, a bending test was performed at a test speed of 3 mm / min, a 0 ° direction test with a span distance of 35 mm, and a 90 ° direction test with a span distance of 35 mm. A bending test piece having the following size was used. The results are shown in FIGS.
0 ° bending test piece: width 20 mm, length 50 mm, thickness 2.1 to 2.3 mm
90 ° bending test piece: width 20 mm, length 50 mm, thickness 2.1-2.3 mm

  In the 0 ° direction bending test, as shown in FIG. 4, the bending strength and the bending elastic modulus increased as the resin impregnation rate increased.

  The bending characteristics were measured at four levels of 10 minutes, 15 minutes, 20 minutes, and 40 minutes in the 90 ° direction. FIG. 7 shows the results of the resin impregnation rate (ratio of the impregnated region containing the thermoplastic fiber in the fiber yarn bundle) according to the heat compression time. Incidentally, the resin impregnation rate was 57% at 10 minutes by heating and compression, 89% at 15 minutes, 92% at 20 minutes, and 95% at 40 minutes. The fiber volume impregnation rate (Vf) at that time was as shown in the following table (Table 2).

  In the 90 ° direction bending test, as shown in FIGS. 5 and 6, the bending strength is almost the same when the resin impregnation rate is 90% or more (that is, the non-impregnated portion is 10% or less), and the flexural modulus is the resin impregnation. It grew as the rate improved.

  As described above, it was confirmed that as the para-aramid fiber and the thermoplastic resin became uniform, the void region was suppressed, and a composite material having a high elastic modulus and high strength was obtained.

It is the schematic which shows a braid structure. It is a graph which shows the relationship between the resin impregnation rate in the composite material of this invention, and molding time. It is a graph which shows the relationship between the tensile elasticity modulus and tensile strength, and resin impregnation rate in the composite material of this invention. It is a graph which shows the relationship between the bending elastic modulus and bending strength by the 0 degree bending test in the composite material of this invention, and a resin impregnation rate. It is a graph which shows the relationship between the bending elastic modulus by the 90 degree bending test in the composite material of this invention, and a resin impregnation rate. It is a graph which shows the relationship between the bending strength by the 90 degree bending test in the composite material of this invention, and a resin impregnation rate. It is a graph which shows the relationship between the resin impregnation rate in the composite material of this invention, and molding time. It is a figure which shows one Embodiment which manufactures the composite material of this invention. It is a figure which shows one Embodiment which manufactures the composite material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Para system aramid fiber 2 Thermoplastic resin fiber 3 Thermoplastic resin film 4 Fiber bundle 11 which consists of para system aramid fiber and thermoplastic resin fiber 12 Braid 12 which uses para system aramid fiber as a core thread 12 Mold

Claims (6)

  A braid comprising a para-aramid fiber as a reinforcing material and a thermoplastic resin as a matrix, the braid comprising the para-aramid fiber as a core yarn and the thermoplastic resin fiber as a braid, or the braid and the thermoplastic resin film or non-woven fabric And a laminated material obtained by heat compression molding.   The composite material according to claim 1, wherein the para-aramid fiber is a polyparaphenylene terephthalamide fiber.   The composite material according to claim 1 or 2, wherein the content of para-aramid fiber is 5 to 80% by weight.   The thermoplastic resin is polyester resin, polyamide resin, polyoxymethylene resin, polycarbonate resin, polyphenylene sulfide resin, modified polyphenylene ether resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyketone resin, polyarylate resin, poly The nitrile resin, the polyetherketone resin, the polyetheretherketone resin, the polyetherketoneketone resin, the polyimide resin, the polyamideimide resin, the fluororesin, and the liquid crystal polymer resin. The composite material according to Item.   A molded body obtained by molding the composite material according to any one of claims 1 to 4.   It is a machine element for industrial use such as reinforcement, friction / sliding, automobiles, ships, etc., electrical / electronic equipment, AV equipment, OA equipment, building parts / members, building materials, joinery, packings or seals The molded product according to claim 5.