JP6791467B2 - Method for manufacturing carbon short fiber resin structure and carbon short fiber resin structure - Google Patents

Description

The present invention relates to a carbon short fiber resin structure and a method for producing a carbon short fiber resin structure.

The carbon fiber reinforced resin composite, which is a composite of carbon fiber and resin, has strength and elastic modulus comparable to that of a metal material, but has a smaller specific gravity than that of a metal material, so that the weight of the member can be reduced. In addition, since it has no rusting problem and is resistant to acids and alkalis, it is used in electronic equipment materials, electrical equipment materials, civil engineering materials, building materials, automobile materials, aircraft materials, and various manufacturing industries. It is used in manufacturing parts such as robots and rolls.

The carbon fiber reinforced resin composite is a composite of a carbon fiber fabric and a resin such as a thermosetting resin or a thermoplastic resin. Carbon fiber fabrics include fabrics using long carbon fibers and fabrics using short carbon fibers. Examples of the fabric using carbon long fibers include a carbon long fiber woven fabric, a carbon long fiber unidirectional web, and a carbon long fiber spread yarn sheet. As a cloth using carbon short fibers, there is a carbon short fiber non-woven fabric. Examples of the carbon long fiber spread yarn sheet include a carbon long fiber spread yarn woven fabric, a carbon long fiber spread yarn unidirectional web (carbon long fiber spread yarn UD web, UD: UniDirection) and the like. The most common carbon fiber reinforced resin composite is a composite of a long fiber woven fabric and a thermosetting resin, but it is difficult to design, it is not a homogeneous material, the molding process time is long, it is expensive, etc. There was a problem.

In addition, carbon long fiber spread yarn UD web, which is a kind of carbon fiber cloth using long carbon fiber, is impregnated with a thermoplastic resin and conveyed in a heating furnace while being sandwiched between a pair of upper and lower steel belt conveyors. A method of combining a carbon long fiber spread fiber UD web and a thermoplastic resin has also been proposed (see, for example, Patent Document 1). The carbon long fiber spread fiber UD web has a problem that fibers are likely to be displaced or moved.

As a carbon fiber reinforced resin composite that solves these problems, a method of kneading short carbon fibers with a thermoplastic resin and using it as a composite for injection molding (see, for example, Patent Document 2) is known. In addition, carbon fibers are easily broken during kneading and the fiber length is shortened, so that not only sufficient properties cannot be obtained, but also it is difficult to obtain a film-like structure of several hundred microns or less.

As another method, a method has been proposed in which a non-woven fabric containing carbon short fibers (carbon short fiber non-woven fabric) is prepared in advance, and the carbon short fiber non-woven fabric and the thermoplastic resin film are composited by a hot press molding method (for example). , Patent Documents 2 to 7). Further, a method has been proposed in which a short carbon fiber non-woven fabric and a thermoplastic resin film are pressed by using a roll unit composed of a combination of a heating roll and a cooling roll to melt and solidify the thermoplastic resin to form a composite (for example, a patent). Reference 8). Further, a method has also been proposed in which a short carbon fiber non-woven fabric and a thermoplastic resin film are laminated, and the thermoplastic resin film is impregnated into the short carbon fiber non-woven fabric by electromagnetic induction heating and then pressed to be composited (for example, a patent). References 9 to 11). As a method of melting the thermoplastic resin film, a method of spraying superheated steam has also been proposed (see, for example, Patent Document 12).

However, the carbon short fiber resin structure, which is simply a composite of a carbon short fiber non-woven fabric and a thermoplastic resin, can obtain sufficient strength physical properties as compared with a carbon fiber reinforced resin composite using long fibers. There was a problem that it was difficult.

From the viewpoint of processability, at least one of the sheet-shaped carbon fiber reinforced resin composites is intended to obtain a roll-shaped wound body obtained by winding the sheet-shaped carbon fiber reinforced resin composite and winding it into a roll shape. A method of laminating and integrating one or more selected from the group consisting of a film, a woven fabric or a non-woven fabric on a surface has also been proposed (see, for example, Patent Document 13). However, in the case of a carbon fiber reinforced resin composite composed of a carbon long fiber spread yarn UD web and a thermoplastic resin, it is necessary to laminate and integrate a film or the like, but the carbon short fiber non-woven fabric and the thermoplastic resin It is described that in the case of the carbon fiber reinforced resin composite composed of the above, it is not always necessary to laminate and integrate the film or the like because it is relatively excellent in flexibility.

Japanese Unexamined Patent Publication No. 2000-355629 Japanese Unexamined Patent Publication No. 07-156146 Japanese Unexamined Patent Publication No. 2013-208791 Japanese Unexamined Patent Publication No. 2013-20281 Japanese Unexamined Patent Publication No. 2011-21303 Japanese Unexamined Patent Publication No. 2011-194852 Japanese Unexamined Patent Publication No. 2014-224333 JP-A-2004-43985 Japanese Unexamined Patent Publication No. 2005-238758 Japanese Unexamined Patent Publication No. 2008-254437 Japanese Unexamined Patent Publication No. 2014-34162 JP-A-2015-47807 JP-A-2010-229238

An object of the present invention is to provide a carbon short fiber resin structure having excellent strength.

The above problem can be solved by the following invention.

(1) A carbon short fiber resin structure which is a laminate of a non-woven fabric containing carbon short fibers, a thermoplastic film, and a carbon long fiber spread yarn sheet.
(2) The short carbon fiber according to (1) above, wherein the long carbon fiber spread yarn sheet is a laminate of a long carbon fiber spread yarn sheet having a sizing agent content of 1% by mass or less and a thermoplastic film. Resin structure.
(3) The carbon short fiber resin structure according to (1) or (2) above, wherein the non-woven fabric containing carbon short fibers contains microfibrillated cellulose.

(4) By heat-pressing treatment with a roll from both sides of a laminate of a non-woven fabric containing carbon short fibers and a thermoplastic film, the non-woven fabric and the thermoplastic film are integrated to form a carbon short fiber reinforced film. A method for producing a carbon short fiber resin structure, which comprises a step of manufacturing and a step of integrating the carbon short fiber reinforced film and a carbon long fiber nonwoven fabric sheet.
(5) The short carbon fiber according to (4) above, wherein the long carbon fiber spread yarn sheet is a laminate of a long carbon fiber spread yarn sheet having a sizing agent content of 1% by mass or less and a thermoplastic film. A method for manufacturing a resin structure.
(6) The method for producing a carbon short fiber resin structure according to (4) or (5) above, wherein the nonwoven fabric containing carbon short fibers contains microfibrillated cellulose.

According to the present invention, a carbon short fiber reinforced structure having high strength physical properties and excellent workability as compared with a carbon short fiber resin structure formed by simply combining a carbon short fiber non-woven fabric and a thermoplastic resin. You can get a body.

The carbon short fiber resin structure of the present invention is a laminate of a non-woven fabric containing carbon short fibers, a thermoplastic film, and a carbon long fiber spread yarn sheet.

In the present invention, as the non-woven fabric containing carbon short fibers (carbon short fiber non-woven fabric), a wet non-woven fabric or a dry non-woven fabric produced by a wet method or a dry method can be used. The carbon short fiber non-woven fabric can contain a thermoplastic short fiber, a thermoplastic emulsion, or the like as a binder. With this binder, strength can be easily imparted to the short carbon fiber non-woven fabric.

Examples of the carbon short fibers include PAN-based carbon fibers made from polyacrylonitrile and pitch-based carbon short fibers made from pitches. The fiber diameter of the carbon short fibers is preferably 3 μm or more and 20 μm or less, and more preferably 5 μm or more and 15 μm or less. The fiber length of the short carbon fibers is preferably 3 μm or more and 40 mm or less in the case of a wet non-woven fabric, and preferably 20 μm or more and 120 mm or less in the case of a dry non-woven fabric.

In the present invention, recycled carbon short fibers can be used as the carbon short fibers. The recycled carbon fiber is a material obtained by sintering and removing a resin component in an inert gas such as argon or nitrogen or in steam from a carbon fiber and a resin composite once formed as a molded body. In particular, the sintering method using superheated steam is an effective method that is inexpensive and does not pollute the environment because it returns to water when it takes heat in the atmosphere. The resin composite made of prepreg has various forms such as an angle ply laminate, and is usually dropped to a certain size and then sintered to remove the thermosetting resin and cut. In this case, recycled carbon short fibers having different fiber lengths can be obtained.

A method for manufacturing a dry nonwoven fabric will be described. First, short carbon fibers defibrated in the atmosphere are developed on a web and dispersed by a card method or the like. At this time, when thermoplastic short fibers are used together as the binder, the fibers are defibrated and dispersed together with the carbon short fibers and heat-treated. When a thermoplastic emulsion is used in combination as a binder, the thermoplastic emulsion is applied to a web of short carbon fibers and heat-treated. The non-woven fabric is made into a dry non-woven fabric by giving it strength with a binder.

A method for producing a wet non-woven fabric will be described. First, carbon short fibers are defibrated in water, then squeezed with a papermaking net such as a circular net, a short net, a long net, or an inclined short net, and dried and heat-treated to obtain a wet non-woven fabric. Then, as with the dry non-woven fabric, a wet non-woven fabric is obtained by imparting strength with a binder such as a thermoplastic short fiber or a thermoplastic emulsion.

In the present invention, either a dry non-woven fabric or a wet non-woven fabric can be used, but when a thin non-woven fabric is used, it is preferable to use a wet non-woven fabric having excellent fiber dispersibility. Further, when a thick non-woven fabric is used, it is preferable to use a dry non-woven fabric which has a simple manufacturing method and is advantageous for increasing the thickness.

The thermoplastic short fibers include non-crystalline polyvinyl alcohol (vinylon) short fibers, polyester core-sheath short fibers having a low melting point on the surface, unstretched polyester short fibers, polycarbonate (PC) short fibers, and polyolefin short fibers. It has thermoplasticity such as polyolefin core-sheath short fibers whose surface has a low melting point, polyolefin short fibers whose surface is made of acid-modified polyolefin, aliphatic polyamide short fibers, unstretched polyphenylene sulfide short fibers, and polyether ketone ketone short fibers. Examples include short resin fibers.

As the thermoplastic emulsion, an emulsion of a resin having thermoplasticity such as acrylic resin, styrene acrylic resin, acid-modified polyolefin, polyolefin containing acid-modified α-olefin, ionomer, and chlorinated polyolefin is used.

The melting point of the thermoplastic resin is preferably 60 ° C. or higher and 260 ° C. or lower, more preferably 60 ° C. or higher and 230 ° C. or lower, further preferably 60 ° C. or higher and 180 ° C. or lower, and 80 ° C. or higher and 160 ° C. It is particularly preferable that the temperature is below ° C.

The fiber diameter of the thermoplastic short fiber is preferably 3 μm or more and 40 μm or less, and more preferably 5 μm or more and 20 μm or less. The fiber length of the thermoplastic short fiber is preferably 1 μm or more and 120 mm or less, and more preferably 3 μm or more and 40 mm or less.

The content ratio of the carbon short fibers and the binder (carbon short fibers: binder according to the mass standard) is preferably 8.5: 0.0 to 5: 4, preferably 8.5: 0.5 to 5. It is more preferably 5: 4, and even more preferably 8: 1 to 6: 3. Although the binder is not an essential component, the strength of the carbon short fiber resin structure can be easily increased by setting the content ratio of the carbon short fibers and the binder within the above range.

In the method for producing a carbon short fiber resin structure of the present invention, the non-woven fabric and the thermoplastic film are integrated by heat-pressing the laminated body of the carbon short fiber-containing non-woven fabric and the thermoplastic film with a roll. It includes a step of manufacturing the carbon short fiber reinforced film and a step of integrating the carbon short fiber reinforced film and the carbon long fiber non-woven fabric sheet. In the present invention, the short carbon fiber non-woven fabric preferably contains microfibrillated cellulose. When the carbon short fiber non-woven fabric contains microfibrillated cellulose, carbon is contained in the carbon short fiber non-woven fabric during heat and pressure treatment or when the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet are integrated. Since the dispersibility of the short fibers does not collapse, a carbon short fiber resin structure having excellent strength physical properties and processability can be obtained.

The microfibrillated cellulose fiber is not a film-like fiber, but a fiber-like fiber having a portion mainly divided in a direction parallel to the fiber axis, and at least a part thereof has a fiber diameter of 1 μm or less. The aspect ratio of length to width is preferably 20-100,000. Further, the modified drainage degree is preferably 0 ml or more and 770 ml or less, and more preferably 0 ml or more and 600 ml or less. Further, the mass average fiber length is preferably 0.1 mm or more and 2 mm or less. The modified drainage degree in the present invention is determined by using a wire mesh (manufactured by PULP AND PAPER RESEARCH INSTITUTE OF CANADA) having a wire diameter of 0.14 mm and a mesh size of 0.18 mm as a sieving plate, except that the sample concentration is 0.1%. It is the degree of drainage measured according to JIS P8121 (1995 version).

The degree of fibrillation of microfibrillated cellulose can also be determined by the viscosity of the dispersion at a low concentration. The higher the viscosity, the more fibrillation progresses, but if the viscosity is too high, the fiber length may be too short. The viscosity of the dispersion of microfibrillated cellulose (concentration 0.5% by mass) is 50 cp or more and 200 cp when a B-type viscometer (rotor No. 2, rotor rotation speed 60 rpm, temperature 23 ° C or higher and 25 ° C or lower) is used. The following is preferable.

When the carbon short fiber non-woven fabric contains microfibrillated cellulose, the content thereof is not particularly limited, but is preferably 0.5 to 20% by mass, preferably 2 to 15% by mass, based on the total fibers in the non-woven fabric. More preferably. When the content of the microfibrillated cellulose fibers is within the above range, carbon is contained in the carbon short fiber non-woven fabric during heat and pressure treatment or when the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet are integrated. Since the dispersibility of the short fibers does not collapse, a carbon short fiber resin structure having excellent strength physical properties and processability can be obtained. When the content of the microfibrillated cellulose fiber is less than the above range, the effect may not be different from the case where the microfibrillated cellulose fiber is not contained. When the content of the microfibrillated cellulose fibers exceeds the above range, after dehydration during the production of the non-woven fabric, the microfibrillated celluloses form a dense structure to form a film, which is formed during heat and pressure treatment or carbon short. When integrating the fiber-reinforced film and the carbon-long fiber spread yarn sheet, it becomes difficult for the thermoplastic resin film to enter the carbon short-fiber non-woven fabric. In addition, voids may be seen in the carbon short fiber reinforced film formed by integrating the carbon short fiber non-woven fabric and the thermoplastic film.

Examples of the cellulose material for microfibrillated cellulose fibers include plant pulp, solvent-spun cellulose, semi-synthetic cellulose and the like. Examples of the vegetable pulp include wood-based pulp such as kraft pulp (KP) using softwood (L material) and softwood (N material), dissolving pulp (DP), and dissolving kraft pulp (DKP). Also included are non-wood pulps such as straw, hemp, cotton and cotton linters. Examples of commercially available products include Serish (registered trademark, manufactured by Daicel Fine Chem Ltd.). The crystal form of the cellulose material includes type I, type II, type III, type IV and the like, but from the viewpoint of heat resistance, type I and type II are preferable, and type I is more preferable. The I-type cellulose material source is non-wood pulp such as cotton pulp, cotton linter pulp, hemp pulp, and kenaf pulp, and lignin obtained from pulp, L material, or N material having a reduced content of lignin and hemicellulose. And wood-based pulp such as KP, DP and DKP with reduced hemicellulose content. In particular, cotton-based materials are preferable.

To obtain microfibrillated cellulose, the cellulosic material is first dispersed in water and mechanically ground. Then, the fibers of the cellulose material are defibrated to form microfibrils. Examples of the apparatus for defibrating the cellulose material include a disc refiner, a millstone type grinder, a high pressure homogenizer, a ball mill, an underwater counter-collision method apparatus, an ultrasonic crusher and the like. These devices can also be used in combination as appropriate.

Examples of the carbon long fiber spread yarn sheet include a carbon long fiber spread yarn unidirectional web (carbon long fiber spread yarn UD web, UD: UniDirection), a carbon long fiber spread yarn woven fabric, and the like. The carbon long fiber spread fiber UD web is a tape-like material obtained by opening a filamentous composite of carbon long fibers and a sizing agent by air flow, water flow, or the like. The carbon long fiber spread fiber woven fabric is a woven fabric using the carbon long fiber spread fiber UD web as a warp and a weft.

In the present invention, this long carbon fiber spread yarn sheet may be used as it is, but a cleaning treatment is performed by a solvent treatment method, an oxidation method, a sintering method, etc. to remove the sizing agent, and the film is formed into a thermoplastic film. It is more preferable to use a laminated carbon long fiber spread yarn sheet. The solvent treatment method is a method of removing the sizing agent with an organic solvent such as acetone, methyl ethyl ketone, alcohol, etc. to expose the surface of long carbon fibers. The oxidation method is a method of removing a sizing agent by oxidative decomposition by using sulfuric acid and hydrogen peroxide in combination. The sintering method is a method of thermally decomposing a sizing agent in a temperature range of 400 ° C. or higher and 700 ° C. or lower in an inert gas such as argon or nitrogen or superheated steam. The sintering method is a preferable method because the scale can be increased simply by introducing a heat source without using other chemical species. In particular, the sintering method using superheated steam is a more preferable method because the oxygen concentration in the atmosphere can be suppressed to a low level and deterioration of the carbon fiber surface can be prevented. In the present invention, the content of the sizing agent in the long carbon fiber spread yarn sheet before being laminated with the thermoplastic film is preferably 0.001% by mass or more and 3% by mass or less. A more preferable content is 0.01% by mass or more and 1% by mass or less.

Examples of the thermoplastic resin of the thermoplastic resin film include polyolefin resins such as polyethylene resin, polypropylene resin and polybutylene resin; acrylic resins such as polymethylmethacrylate resin; polystyrene resin, acryliconitrile, butadiene, and styrene (). Polystyrene-based resins such as Stylene copolymer synthetic resin (ABS resin), acryliconirile / styrene copolymer synthetic resin (AS resin); polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, poly Polyester resins such as trimethylene terephthalate resin, polyethylene naphthalate (PEN) resin, poly 1,4-cyclohexyldimethylene terephthalate (PCT) resin; polyamide (PA) resin such as 6-nylon resin and 6,6-nylon 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; Poly Ether sulfone (PES) resin; Polyketone resin; Polyarylate (PAR) resin; Polyether nitrile (PEN) resin; Polyether ketone (PEK) resin; Polyether ether ketone (PEEK) resin; Polyether ketone ketone (PEKK) resin Polyethylene (PI) resin; Polyamiimide (PAI) resin; Fluorine (F) resin; Liquid crystal polymer resin such as liquid crystal polyester resin; Polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based Alternatively, a fluoroplastic elastomer such as fluorine; or a copolymer resin or modified resin thereof; an ionomer resin and the like can be mentioned. From these resins, one type or two or more types can be used. From the viewpoint of mass, PP is preferable, and from the viewpoint of flammability, PC, PPS, PEEK, PEI and the like are preferable.

Examples of the ionomer resin include an ethylene-based ionomer resin obtained by neutralizing a part of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer resin with metal ions. A carboxyl group in which 10 mol% or more, preferably 10 mol% or more and 90 mol% or less is neutralized with a metal ion is used. Examples of the metal ion include alkali metals such as lithium and sodium, and polyvalent metal ions such as alkaline earth metals such as zinc, magnesium and calcium.

In the method for producing a carbon short fiber resin structure of the present invention, the non-woven fabric and the thermoplastic film are integrated by heat-pressing the laminated body of the carbon short fiber non-woven fabric and the thermoplastic film with a roll. It includes a step of producing a carbon short fiber reinforced film and a step of integrating the carbon short fiber reinforced film and a carbon long fiber non-woven fabric sheet.

In the process of producing the carbon short fiber reinforced film, heat and pressure treatment is performed with a roll from both sides of the laminate of the carbon short fiber non-woven fabric and the thermoplastic film. Further, a laminate of the long carbon fiber spread yarn sheet and the thermoplastic film is also obtained by heat-pressing treatment with a roll from both sides of the laminate. Further, in the step of integrating the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet, heat and pressure treatment is performed with a roll from both sides of the laminate of the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet. You can also do it. Further, at the time of press molding, the carbon long fiber spread yarn sheet can be integrated only in the necessary part of the carbon short fiber reinforced film.

As the heating temperature, around the melting point of the thermoplastic film is appropriate, but it is necessary to pay attention to the temperature change or runout during operation or in the pressurized place, and when the temperature shake becomes large, the non-woven fabric or film becomes Since tearing and uneven penetration of the thermoplastic film into the non-woven fabric occur, the temperature fluctuation is preferably within 1 ° C., more preferably within 0.5 ° C. The pressurization is preferably 10 N / mm or more and 600 N / mm or less in terms of linear pressure. The speed is preferably 1 m / min or more and 100 m / min or less, and more preferably 3 m / min or more and 40 m / min or less. These conditions need to be adjusted as appropriate depending on the material selected.

The rolls are arranged in pairs on both sides of the laminated body, but may be a single pair or a plurality of pairs may be used. Further, for super engineering plastic-based thermoplastic films, a device for preheating can be provided.

As a laminate for producing a carbon short fiber reinforced film, a laminate composed of one layer of carbon short fiber non-woven fabric and one layer of thermoplastic film is arranged on both sides of the one layer of carbon short fiber non-woven fabric. Laminates, laminates in which carbon short fiber non-woven fabrics are arranged on both sides of one layer of thermoplastic film, laminates in which a plurality of carbon short fiber non-woven fabrics and a plurality of thermoplastic films are alternately arranged, a plurality of carbon short fiber non-woven fabrics and a plurality of Examples thereof include a laminate in which the thermoplastic films of the above are randomly arranged. However, if the thickness of the produced carbon short fiber reinforced film becomes too thick, it becomes difficult to wind it into a roll. Therefore, the thickness of the carbon short fiber reinforced film is preferably 20 μm or more and 500 μm or less, preferably 30 μm or more. It is more preferably 250 μm or less.

As the roll, it is necessary to maintain the surface temperature with high accuracy in the roll axis direction, so a jacket chamber having a heat pipe function and an electromagnetic induction heating method capable of forming a multi-layer heating layer in the roll axis direction are used. It is preferable to use a combined roll. Examples of such a roll include an induction heating jacket roll (registered trademark) manufactured by Tokuden Corporation.

The carbon short fiber resin structure of the present invention can also be used in a single layer. Further, the carbon short fiber resin structure can be laminated and used. The carbon monofiber resin structure can be used for various purposes through processing such as hot press molding and vacuum forming.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the present examples. Unless otherwise specified, all parts and percentages in the examples are based on mass.

(Preparation of microfibrillated cellulose)
Linter pulp (mass average fiber length 1.2 mm) was ground using a mascoroider (registered trademark, device name: MKZA12) manufactured by Masuko Sangyo Co., Ltd. to prepare microfibrillated cellulose (MFC). Further, the treatment was performed 4 times at 50 MPa using a high-pressure homogenizer (MC2 manufactured by BOS). The viscosity of the microfibrillated cellulose dispersion (concentration 0.5% by mass) was measured with a B-type viscometer (rotor No. 2, rotor speed 60 rpm, temperature 23 ° C or higher and 25 ° C or lower) and found to be 170 cp. It was.

(Short carbon fiber)
Short carbon fiber: Fiber diameter 7 μm, fiber length 6 mm

(Thermoplastic short fiber)
Thermoplastic short fiber: fiber diameter 4.5 μm, fiber length 3 mm, undrawn PET fiber

(Manufacturing of carbon short fiber non-woven fabric 1)
With a fiber content of 85% by mass of short carbon fibers and 15% by mass of thermoplastic short fibers, the fibers were dispersed in water for 5 minutes at a dispersion concentration of 0.2% by mass, and a 90-mesh circular net paper machine was used. It is squeezed at a speed of 3 m / min and dried for 10 seconds with a Yankee dryer having a surface temperature of 150 ° C. to prepare a short carbon fiber non-woven fabric having a mesh size of 25 g / m ² , a thickness of 120 μm, a width of 40 cm, and a length of 100 m. Wrapped up in.

(Manufacturing of carbon short fiber non-woven fabric 2)
With a fiber content of 80% by mass of carbon short fibers, 15% by mass of thermoplastic short fibers, and 5% by mass of microfibrillated cellulose, the fibers are dispersed in water for 5 minutes at a dispersion concentration of 0.2% by mass, and 90 meshes are used. Machined with a circular net type paper machine at a speed of 3 m / min, dried with a Yankee dryer with a surface temperature of 150 ° C. for 10 seconds, and has a grain size of 25 g / m ² , a thickness of 120 μm, a width of 40 cm, and a length of 100 m. A non-woven fabric was prepared and wound into a roll.

(Manufacturing of carbon short fiber reinforced film 1)
A laminated body of carbon short fiber non-woven fabric 1 and a thermoplastic film (resin: unstretched PP, Toyobo, Toyo Tuck (registered trademark) E-100, melting point 160 ° C.) of 100 μm was heated to 170 ° C. at a speed of 5 m. A short carbon fiber reinforced film 1 having a thickness of 125 μm was produced by sandwiching it at / min and a linear pressure of 80 N / mm.

(Manufacturing of carbon short fiber reinforced film 2)
A carbon short fiber reinforced film having a thickness of 125 μm by sandwiching a laminate of carbon short fiber non-woven fabric 2 and a thermoplastic film (resin: PEEK) of 100 μm between roll pairs heated to 380 ° C. at a speed of 5 m / min and a linear pressure of 150 N / mm. 2 was prepared.

(Manufacturing of carbon short fiber reinforced film 3)
A laminated body of carbon short fiber non-woven fabric 2 and a thermoplastic film (resin: unstretched PP, Toyobo, Toyo Tuck (registered trademark) E-100, melting point 160 ° C.) of 100 μm was heated to 170 ° C. at a speed of 5 m. A short carbon fiber reinforced film 3 having a thickness of 125 μm was produced by sandwiching the film at a linear pressure of 80 N / mm at / min.

(Preparation of long carbon fiber spread yarn sheet 1)
A laminate of carbon long fiber spread yarn UD web (manufactured by Sakai Obex, carbon fiber 12 k, width 20 mm, sizing agent content 3% by mass) and a thermoplastic film (resin: PEEK) of 30 μm was heated to 380 ° C. A carbon long fiber spread fiber sheet 1 having a thickness of 50 μm was prepared by sandwiching the roll pairs at a speed of 5 m / min and a linear pressure of 60 N / mm.

(Preparation of long carbon fiber spread yarn sheet 2)
Carbon long fiber spread fiber UD web (manufactured by Sakai Obex, carbon fiber 12k, width 20 mm, sizing agent content 3% by mass) and thermoplastic film (resin: unstretched PP, Toyobo, Toyo Tuck (registered trademark)) A laminate having an E-100 and a melting point of 160 ° C.) of 30 μm was sandwiched between roll pairs heated to 170 ° C. at a speed of 5 m / min and a linear pressure of 60 N / mm to prepare a carbon long fiber spread fiber sheet 2 having a thickness of 50 μm.

(Preparation of long carbon fiber spread yarn sheet 3)
Carbon long fiber spread yarn UD web (manufactured by Sakai Obex, carbon fiber 12k, width 20 mm) is heat-treated in superheated steam at 580 ° C. for 1 hour, and then laminated with a thermoplastic film (resin: PEEK) of 30 μm. Next, the roll pair heated to 380 ° C. was sandwiched at a speed of 5 m / min and a linear pressure of 150 N / mm to prepare a carbon long fiber spread fiber sheet 3 having a thickness of 50 μm. The sizing agent content of the carbon long fiber spread fiber UD web after the washing treatment was 0.1% by mass or less.

(Preparation of long carbon fiber spread yarn sheet 4)
Carbon long fiber spread fiber UD web (manufactured by Sakai Obex, carbon fiber 12k, width 20 mm) is heat-treated with superheated steam at 580 ° C. for 1 hour, and then a thermoplastic film (resin: unstretched PP, manufactured by Toyobo). It was laminated with Toyobo (registered trademark) E-100, melting point 160 ° C.) 30 μm, and then sandwiched between roll pairs heated to 170 ° C. at a speed of 5 m / min and a linear pressure of 60 N / mm to open carbon fiber with a thickness of 50 μm. The fiber thread sheet 4 was produced. The sizing agent content of the carbon long fiber spread fiber UD web after the washing treatment was 0.1% by mass or less.

(Preparation of long carbon fiber spread yarn sheet 5)
Carbon long fiber spread woven fabric (made by Sakai Obex, woven fabric with carbon fiber 12k, width 3 mm, thickness 95 μm, sizing agent content 3% by mass), thermoplastic film (resin: unstretched PP, Toyobo, Toyo Tuck (Registered trademark) E-100, melting point 160 ° C.) 30 μm was laminated on both sides, and then sandwiched between roll pairs heated to 170 ° C. at a speed of 5 m / min and a linear pressure of 60 N / mm, and a carbon fiber having a thickness of 100 μm. The spread fiber sheet 5 was produced.

(Preparation of long carbon fiber spread sheet 6)
Carbon long fiber spread woven fabric (manufactured by Sakai Obex, carbon fiber 12k, woven fabric thickness 95 μm with a width of 3 mm) is heat-treated with superheated steam at 580 ° C for 1 hour, and then a thermoplastic film (resin: unstretched PP, Toyobo). Made by Toyobo (registered trademark) E-100, melting point 160 ° C), 30 μm was laminated on both sides, and then sandwiched between roll pairs heated to 170 ° C at a speed of 5 m / min and a linear pressure of 60 N / mm, and a thickness of 100 μm. The carbon long fiber spread fiber sheet 6 of the above was prepared. The sizing agent content of the long carbon fiber spread yarn woven fabric after the washing treatment was 0.1% by mass or less.

(Examples 1 to 3)
The carbon short fiber resin structures of Examples 1 to 3 were obtained by combining the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet shown in Table 1. Combining 31 carbon short fiber reinforced films and 2 carbon long fiber spread yarn sheets on both sides, 1 carbon long fiber spread paper sheet / 31 carbon short fiber reinforced films / 1 sheet The carbon long fiber spread fiber sheets were laminated and integrated in this order to obtain a carbon short fiber resin structure having a thickness of 4 mm. A press molding method was used for integration, and when the thermoplastic film was unstretched PP, heat treatment was performed at a temperature of 170 ° C., a pressure of 0.5 MPa, and 1 minute after the temperature rise. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out with the direction parallel to the fiber direction of the long carbon fibers as the length. When the thermoplastic film is unstretched PP, the test piece is heat-treated at 120 ° C. for 3 hours and then cooled, and then cooled to a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered). Its flexural modulus was measured under the trademark AutoCOM) AC-100). The results of the average values are shown in Table 1.

(Examples 4 to 5)
The carbon short fiber resin structures of Examples 4 and 5 were obtained by combining the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet shown in Table 1. Combining 31 carbon short fiber reinforced films and carbon long fiber spread yarn sheets on both sides, 1 carbon long fiber spread paper sheet / 31 carbon short fiber reinforced film / 1 carbon long fiber The spread fiber sheets were laminated in this order and integrated to obtain a carbon short fiber resin structure having a thickness of 4 mm. A press molding method was used for integration, and when the thermoplastic film was PEEK, it was produced by heating at a temperature of 360 ° C., a pressure of 5 MPa, and heating for 3 minutes after raising the temperature. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out with the direction parallel to the fiber direction of the long carbon fibers as the length. When the thermoplastic film is PEEK, the test piece is heat-treated at 200 ° C. for 4 hours and then cooled, and then cooled to a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered trademark, registered trademark)). The flexural modulus was measured with AutoCOM) AC-100). The results of the average values are shown in Table 1.

(Examples 6 to 7)
The carbon short fiber resin structures of Examples 6 and 7 were obtained by combining the carbon short fiber reinforced film and the carbon long fiber spread sheet shown in Table 1. Combining 30 carbon short fiber reinforced films and 2 carbon long fiber spread yarn sheets on both sides, 1 carbon long fiber spread paper sheet / 30 carbon short fiber reinforced films / 1 sheet The carbon long fiber spread fiber sheets were laminated and integrated in this order to obtain a carbon short fiber resin structure having a thickness of 4 mm. A press molding method was used for integration, and when the thermoplastic film was unstretched PP, heat treatment was performed at a temperature of 170 ° C., a pressure of 0.5 MPa, and 1 minute after the temperature rise. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out. When the thermoplastic film is PP, the test piece is heat-treated at 120 ° C. for 3 hours and then cooled to be a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered trademark, registered trademark)). The flexural modulus was measured with AutoCOM) AC-100). The results of the average values are shown in Table 1.

(Comparative Example 1)
32 layers of carbon short fiber reinforced film 2 were laminated and integrated to obtain a comparative carbon short fiber resin structure having a thickness of 4 mm. A press molding method was used for integration, and when the thermoplastic film was PEEK, it was produced by heating at a temperature of 360 ° C., a pressure of 5 MPa, and heating for 3 minutes after raising the temperature. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out. The test piece is heat-treated at 150 ° C. for 3 hours and then cooled, and then cooled with a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered trademark, AutoCOM) AC-100). The flexural modulus was measured. The results of the average values are shown in Table 1.

(Comparative Example 2)
32 layers of carbon short fiber reinforced film 3 were laminated and integrated to obtain a comparative carbon short fiber resin structure having a thickness of 4 mm. A press molding method was used for integration, and when the thermoplastic film was unstretched PP, heat treatment was performed at a temperature of 170 ° C., a pressure of 0.5 MPa, and 1 minute after the temperature rise. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out. The test piece is heat-treated at 150 ° C. for 3 hours and then cooled, and then cooled with a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered trademark, AutoCOM) AC-100). The flexural modulus was measured. The results of the average values are shown in Table 1.

(Comparative Example 3)
31 layers of short carbon fiber non-woven fabric 2 and 31 layers of thermoplastic film (resin: unstretched PP, manufactured by Toyo Boseki, Toyo Tuck (registered trademark) E-100, melting point 160 ° C.) 30 μm are alternately layered to carbon. Alternate laminated product of short fiber non-woven fabric 2 and thermoplastic film, and further laminated carbon long fiber spread yarn sheet 4 on both sides, one carbon long fiber spread paper sheet / alternate laminated product / one carbon length When the fiber spread paper sheets were laminated in this order, heated at a temperature of 170 ° C. and a pressure of 0.5 MPa for 5 minutes, and then integrated by a press molding method, the air inside the carbon short fiber non-woven fabric remained. , A large amount of bubbles were generated, and a carbon short fiber resin structure in a state where the bubbles remained was obtained. From the obtained structure, five test pieces having a length of 80 mm and a width of 10 mm were cut out with the direction parallel to the fiber direction of the long carbon fibers as the length. When the thermoplastic film is unstretched PP, the test piece is heat-treated at 120 ° C. for 3 hours and then cooled, and then cooled to a universal material testing machine (TSE Co., Ltd., device name: Autocom (registered). Its flexural modulus was measured under the trademark AutoCOM) AC-100). The results of the average values are shown in Table 1.

Comparing Examples 1 to 3 and 6 to 7 with Comparative Example 2, a carbon short fiber reinforced film and a carbon long fiber spread yarn sheet are compared with a structure consisting of only a carbon short fiber reinforced film (Comparative Example 2). The flexural modulus was improved in all of the structures (Examples 1 to 3) which were laminated with the above. Further, when Examples 4 to 5 and Comparative Example 1 are compared, the carbon short fiber reinforced film and the carbon long fiber spread yarn sheet are compared with the structure composed of only the carbon short fiber reinforced film (Comparative Example 1). The flexural modulus of each of the laminated structures (Examples 4 to 5) was improved.

Comparing Examples 2 and 3, the structure of Example 2 in which the content of the carbon length fiber sizing agent in the carbon length fiber spread yarn sheet is 0.1% by mass or less has an amount of 3% by mass of the sizing agent. The flexural modulus was improved as compared with the structure of Example 3 which was%. Comparing Examples 4 and 5, the structure of Example 4 in which the content of the carbon filament sizing agent in the carbon filament spread fiber sheet is 0.1% by mass or less has an amount of 3 mass of the sizing agent. The flexural modulus was improved as compared with the structure of Example 5 which was%.

Comparing Example 2 and Comparative Example 3, a step of producing a carbon short fiber reinforced film by heat-pressing treatment with a roll from both sides of a laminate of a carbon short fiber non-woven fabric and a thermoplastic film, and the carbon short fiber Compared with the structure of Example 2 produced by the method for producing a carbon short fiber resin structure including a step of integrating a reinforcing film and a carbon long fiber non-woven fabric sheet, the structure is produced by another production method. In the structure of Comparative Example 3, bubbles were generated and the flexural modulus was lowered.

Comparing Examples 1 and 2, Example 2 in which the carbon short fiber nonwoven fabric contains microfibrillated cellulose is compared with Example 1 in which the carbon short fiber nonwoven fabric does not contain microfibrillated cellulose. The bending elasticity was improved.

The short carbon fiber non-woven fabric and composite of the present invention can be used for electronic device materials, electrical device materials, civil engineering materials, building materials, automobile materials, robots used in various manufacturing industries, manufacturing parts such as rolls, and the like.

Claims (3)

A step of producing a carbon short fiber reinforced film by integrating the non-woven fabric and the thermoplastic film by heat-pressing the laminated body of the non-woven fabric containing carbon short fibers and the thermoplastic film with a roll. When, viewed including the step of integrating the carbon Mototan fiber-reinforced film and the carbon long fibers opened yarn sheet, roll is a roll in combination with a jacket chamber, an electromagnetic induction heating method having a heat pipe function carbon A method for manufacturing a short fiber resin structure. The carbon short fiber resin structure according to claim 1, wherein the carbon long fiber spread yarn sheet is a laminate of a carbon long fiber spread yarn sheet having a sizing agent content of 1% by mass or less and a thermoplastic film. Production method. The method for producing a carbon short fiber resin structure according to claim 1 or 2, wherein the nonwoven fabric containing carbon short fibers contains microfibrillated cellulose.