JP2020158749A - Poly vinyl chloride-based carbon fiber-reinforced composite material - Google Patents

Abstract

To provide a CFRP using a vinyl chloride-based resin composition having good impregnation property to a carbon fiber substrate.SOLUTION: There is provided a carbon fiber-reinforced composite material according to the invention comprising a vinyl chloride-based resin composition (A) and a carbon fiber substrate (B). The vinyl chloride-based resin composition (A) comprises a vinyl chloride-based resin and at least one kind of additive, and the vinyl chloride-based resin composition (A) has a complex viscosity η at 200°C and a frequency of 10 Hz of 1<η<1500. The vinyl chloride-based resin has an average degree of polymerization of 400 or more and 1500 or less. In the vinyl chloride-based resin composition (A), the content of a thermal stabilizer is 0.1 to 30 pts.mass and the content of an internal lubricant is 20 pts.mass or less and the content of an external lubricant is 10 pts.mass or less based on 100 pts.mass of the vinyl chloride-based resin.SELECTED DRAWING: None

Description

The present invention relates to a carbon fiber reinforced composite material in which a carbon fiber base material is impregnated with a vinyl chloride resin composition.

A carbon fiber reinforced composite material composed of carbon fiber and a matrix resin (hereinafter, may be abbreviated as CFRP) has high specific strength and specific elastic modulus, excellent mechanical properties, and high functional properties such as weather resistance and chemical resistance. Has. Therefore, CFRP is attracting attention in aircraft structural members, wind turbine blades, automobile outer panels, and general industrial applications, and its demand is increasing year by year.

As the matrix resin, a thermosetting resin typified by an epoxy resin which has a low viscosity when impregnated with carbon fibers and has excellent adhesion to carbon fibers has been conventionally known. In recent years, as matrix resins, thermoplastic resins such as polyolefins and polyamide-based polymer alloys have been developed due to the demand for improved impact resistance, high productivity, and interest in recycling.

In order to take advantage of the excellent properties of carbon fibers such as weight reduction and mechanical strength, it is important that the carbon fibers are uniformly dispersed in the matrix resin, and it is necessary that the resin viscosity at the time of impregnation is low. .. However, in general, thermoplastic resins may undergo thermal decomposition under high temperature conditions, and many of them have high viscosities even in a molten state, which tends to cause problems such as insufficient resin impregnation.

On the other hand, in order to take advantage of the excellent mechanical properties of carbon fibers, it is also important that the interfacial adhesiveness between the carbon fibers and the matrix resin is excellent. For example, in a propylene-based resin, the interfacial adhesiveness to carbon fibers is poor, and it is difficult to obtain the expected mechanical properties even if the propylene-based resin and carbon fibers are simply melt-kneaded. As a method for improving this problem, a modified propylene resin in which maleic anhydride or the like is graft-bonded to a propylene resin has been developed, and by adding this, the interfacial adhesiveness between the propylene resin and the carbon fiber can be improved. It is planned.

By solving the above problems in terms of materials and processes, CFRP using polyolefin, polyamide-based polymer alloy, etc. as the matrix resin has been put into practical use, but it still has chemical resistance and flame retardancy depending on the matrix resin. Inferior performance was sometimes a problem.

Vinyl chloride resin, which is a general-purpose thermoplastic resin, is a material that has excellent flame retardancy, durability, oil resistance and chemical resistance, has extremely little creep deformation compared to ethylene-based resin and propylene-based resin, and has excellent mechanical strength. Is known to be.

However, vinyl chloride resin has the highest melt viscosity among thermoplastic resins, and the processing temperature when impregnating carbon fibers with vinyl chloride resin is close to the thermal decomposition temperature of vinyl chloride resin, making it difficult to impregnate carbon fibers. It is presumed to be accompanied, and no practical example is seen. In fact, in Patent Document 1, the vinyl chloride resin is only treated as a mixture with a thermosetting resin that dissolves the vinyl chloride resin while remaining in the blending amount as an auxiliary component.

Since the vinyl chloride resin is a polar polymer having a chlorine group, it is presumed that the interfacial adhesiveness with carbon fibers is superior to that of the non-polar polymer propylene resin. However, since vinyl chloride resin is prone to thermal decomposition and adhesion to the mold during molding, a heat stabilizer that suppresses the thermal decomposition reaction is blended, and screws and molds that need to be contacted during the molding process. In order to prevent adhesion to the metal surface such as, it is essential to add a lubricant or the like. Therefore, vinyl chloride resins generally have a higher content ratio of additives than other thermoplastic resins. As a result, it is not known at present how the high content of the additive affects the interfacial adhesiveness between the vinyl chloride resin composition containing a large amount of the additive and the carbon fiber.

JP-A-2017-95537

As described above, the vinyl chloride resin composition has a high melt viscosity, low thermal stability, and a high additive content ratio. Therefore, it is presumed that the vinyl chloride-based resin composition is difficult to impregnate the carbon fiber base material and is difficult to composite. At present, it has not been sufficiently investigated and elucidated what kind of vinyl chloride resin composition is suitable for CFRP preparation. Therefore, there is still a demand for a vinyl chloride resin composition having good impregnation property into the carbon fiber base material. Further, there is a demand for CFRP in which a carbon fiber base material is impregnated with such a vinyl chloride resin composition.

As a result of diligent studies, the present inventors have found that the above problems can be solved by using the vinyl chloride resin composition (A) satisfying a specific condition, and the present invention has been made. It came to. That is, the gist of the present invention is as follows.

[1] A carbon fiber reinforced composite material composed of a vinyl chloride resin composition (A) and a carbon fiber base material (B).
The vinyl chloride resin composition (A) contains a vinyl chloride resin and at least one additive.
The vinyl chloride resin composition (A) has a complex viscosity η at 200 ° C. and a frequency of 10 Hz of 1 <η <1500.
The average degree of polymerization of the vinyl chloride resin is 400 or more and 1500 or less.
In the vinyl chloride resin composition (A), the content of the heat stabilizer is 0.1 to 30 parts by mass and the content of the internal lubricant is 20 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The following, a carbon fiber reinforced composite material, characterized in that the external lubricant is 10 parts by mass or less and the content of the plasticizer is 10 parts by mass or less.
[2] The carbon fiber-reinforced composite material according to [1], wherein the vinyl chloride resin composition (A) has a complex viscosity η at 200 ° C. and a frequency of 10 Hz of 10 <η <1000.
[3] At least one of the thermal stabilizers selected from the group consisting of organic tin stabilizers, lead stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, and barium-cadmium stabilizers. The carbon fiber reinforced composite material according to [1] or [2], which is a seed.
[4] The internal lubricant is at least one selected from the group consisting of butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide, [1] to [ 3] The carbon fiber reinforced composite material according to any one of.
[5] The carbon fiber reinforcement according to any one of [1] to [4], wherein the external lubricant is at least one selected from the group consisting of paraffin wax, polyolefin wax, ester wax, and montanic acid wax. Composite material.
[6] In the vinyl chloride resin composition (A), the total content of the additives is 70 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin, according to [1] to [5]. The carbon fiber reinforced composite material according to any one.
[7] Described in any one of [1] to [6], wherein the average bending strength of the three-point bending test is 300 MPa or more when the fiber volume fraction (Vf) of the carbon fiber reinforced composite material is 50 ± 2%. Carbon fiber reinforced composite material.
[8] A molded product made of the carbon fiber reinforced composite material according to any one of [1] to [7].

In the present invention, by using the vinyl chloride resin composition (A) satisfying a specific condition, CFRP having excellent impregnation property into the carbon fiber base material (B) and good bending strength can be obtained.

<Carbon fiber reinforced composite material>
The carbon fiber reinforced composite material according to the present invention is a carbon fiber reinforced composite material composed of a vinyl chloride resin composition (A) and a carbon fiber base material (B). Hereinafter, each element constituting the carbon fiber reinforced composite material will be described in detail.

<Vinyl chloride resin composition (A)>
The vinyl chloride resin composition (A) preferably has excellent impregnation property into the carbon fiber base material (B). The vinyl chloride resin composition (A) has a complex viscosity η at 200 ° C. and a frequency of 10 Hz in the range of 1 <η <1500, preferably 10 <η <1000 Pa · s, and 20 <η <. It is more preferably 800 Pa · s. When the complex viscosity η is less than 1500 Pa · s, the resin can be impregnated into the inside of the carbon fiber filament bundle, and the excellent mechanical properties of the carbon fiber can be utilized. On the other hand, when the complex viscosity η is more than 1 Pa · s, it is possible to obtain the mechanical strength of the matrix resin itself to the extent that the mechanical strength as CFRP is not impaired.

The vinyl chloride resin composition (A) is preferably excellent in interfacial adhesiveness to the surface of the carbon fiber base material (B), that is, has high compatibility.

The vinyl chloride-based resin used in the vinyl chloride-based resin composition (A) is not particularly limited, and in addition to the homopolymer of the vinyl chloride monomer, for example, (1) vinyl chloride monomer and vinyl chloride monomer. Examples thereof include a copolymer with a polymerizable monomer other than the above, (2) a graft copolymer obtained by grafting a vinyl chloride monomer or a vinyl chloride resin to a polymer other than the vinyl chloride resin. Further, a chlorinated vinyl chloride resin obtained by chlorinating these vinyl chloride resins can also be mentioned. These vinyl chloride resins may be used alone or in combination of two or more.

(1) The polymerizable monomer in the copolymer of the vinyl chloride monomer and the polymerizable monomer other than the vinyl chloride monomer is not particularly limited, but is an α-olefin having 2 or more and 16 or less carbon atoms (1). For example, ethylene, propylene, and butylene); vinyl esters of aliphatic carboxylic acids having 2 or more and 16 or less carbon atoms (for example, vinyl acetate and vinyl propionate); alkyl vinyl ethers having 2 or more and 16 or less carbon atoms (for example, butyl vinyl ether and Cetyl vinyl ether); alkyl (meth) acrylates with 1 to 16 carbon atoms (eg, methyl (meth) acrylate, ethyl (meth) acrylate and butyl acrylate); aryl (meth) acrylate (eg, phenylmethacrylate); aromatic vinyl (For example, styrene and α-substituted styrene (eg, α-methylstyrene)); vinyl halides (eg, vinylidene chloride and vinylidene fluoride); and N-substituted maleimides (N-phenylmaleimide and N-cyclohexylmaleimide). Can be mentioned.

(2) The polymer that gives the graft copolymer together with the vinyl chloride monomer or vinyl chloride resin is any polymer that can be graft-polymerized to the vinyl chloride monomer, regardless of whether it is a homopolymer or a copolymer. Things are also included. For example, a copolymer of α-olefin and vinyl ester (eg, ethylene-vinyl acetate copolymer); a copolymer of α-olefin, vinyl ester and carbon monoxide (eg, ethylene-vinyl acetate-monooxide). Carbon copolymers); copolymers of α-olefins and alkyl (meth) acrylates (eg, ethylene-methylmethacrylate copolymers and ethylene-ethylacrylate copolymers); α-olefins and alkyl (meth) acrylates Copolymer with carbon monoxide (eg, ethylene-butyl acrylate-carbon monoxide copolymer); Copolymer of two or more different α-olefins (eg, ethylene-propylene copolymer); Unsaturated nitrile Copolymers of and diene (eg, acrylonitrile-butadiene copolymers); polyurethanes; and chlorinated polyolefins (eg, chlorinated polyethylene and chlorinated polypropylene).

The average degree of polymerization of the vinyl chloride resin is 400 or more and 1500 or less, and more preferably 400 or more and 800 or less. When the average degree of polymerization is at least the above lower limit value, it is easy to obtain preferable physical properties (for example, toughness) of the vinyl chloride resin. When the average degree of polymerization is not more than the above upper limit value, the impregnation property into the carbon fiber base material (B) becomes good.

(Additive)
Various additives added to the vinyl chloride resin composition (A) include heat stabilizers, lubricants, processing aids, impact modifiers, heat resistance improvers, antioxidants, ultraviolet absorbers, antistatic agents, and light. Stabilizers, fillers, pigments, flame retardants, plasticizers and the like can be mentioned. Only one kind of the additive may be used, or two or more kinds may be used in combination.

The total content of the additives contained in the vinyl chloride resin composition (A) is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of the vinyl chloride resin. It is preferably 50 parts by mass or less, and more preferably 50 parts by mass or less. When the amount is small, the influence of exudation near the interface of the continuous carbon fiber base material (B) can be reduced, and deterioration of physical properties such as bending strength of the carbon fiber reinforced composite material can be suppressed.

The heat stabilizer is not particularly limited, and examples thereof include a heat stabilizer and a heat stabilization aid. The heat stabilizer is not particularly limited, and examples thereof include an organotin stabilizer, a lead stabilizer, a calcium-zinc stabilizer, a barium-zinc stabilizer, and a barium-cadmium stabilizer.

Examples of the organic tin stabilizer include dibutyl tin mercapto, dioctyl tin mercapto, dimethyl tin mercapto, dibutyl tin mercapto, dibutyl tin malate, dibutyl tin malate polymer, dioctyl tin malate, dioctyl tin malate polymer, dibutyl tin laurate, and Examples thereof include dibutyltin laurate polymer. Only one type of the stabilizer may be used, or two or more types may be used in combination.

The heat stabilizing aid is not particularly limited, and examples thereof include epoxidized soybean oil, phosphoric acid ester, polyol, hydrotalcite, and zeolite. As the heat stabilization aid, only one kind may be used, or two or more kinds may be used in combination.

The content of the heat stabilizer contained in the vinyl chloride resin composition (A) is 0.1 part by mass or more and 30 parts by mass or less and 10 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin. It is preferably 5 parts by mass or less, and more preferably 5 parts by mass or less. When the amount is small, the influence of exudation near the interface of the continuous carbon fiber base material (B) can be reduced, and deterioration of physical properties such as bending strength of the carbon fiber reinforced composite material can be suppressed.

Examples of the lubricant include an internal lubricant and an external lubricant. The internal lubricant is used for the purpose of lowering the flow viscosity of the molten resin during molding and preventing frictional heat generation. The internal lubricant is not particularly limited, and examples thereof include butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide. Only one kind of the above-mentioned lubricant may be used, or two or more kinds may be used in combination.

The content of the internal lubricant contained in the vinyl chloride resin composition (A) is 20 parts by mass or less, preferably 10 parts by mass or less, and 5 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The following is more preferable. When the amount is small, the influence of exudation near the interface of the continuous carbon fiber base material (B) can be reduced, and deterioration of physical properties such as bending strength of the carbon fiber reinforced composite material can be suppressed.

The external lubricant is used for the purpose of enhancing the sliding effect between the molten resin and the metal surface during the molding process. The external lubricant is not particularly limited, and examples thereof include paraffin wax, polyolefin wax, ester wax, and montanic acid wax. Only one kind of the above-mentioned lubricant may be used, or two or more kinds may be used in combination.

The content of the external lubricant contained in the vinyl chloride resin composition (A) is 10 parts by mass or less, preferably 5 parts by mass or less, and 2 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The following is more preferable. When the amount is small, the influence of exudation near the interface of the continuous carbon fiber base material (B) can be reduced, and deterioration of physical properties such as bending strength of the carbon fiber reinforced composite material can be suppressed.

The processing aid is not particularly limited, and conventionally known processing aids can be used, and homopolymers or copolymers of alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, alkyl methacrylate, and methyl. Copolymers with alkyl acrylates such as acrylates, ethyl acrylates and butyl acrylates, copolymers of alkyl methacrylates with aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene, alkyl methacrylates and acrylonitrile and methacrylol Examples thereof include copolymers with vinyl cyanide compounds such as nitrile, and these can be used alone or in combination of two or more. Among these, an alkyl acrylate-alkyl methacrylate copolymer having a weight average molecular weight of 100,000 to 2 million can be preferably used. Specific examples thereof include an n-butyl acrylate-methyl methacrylate copolymer and a 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer. As the processing aid, only one kind may be used, or two or more kinds may be used in combination.

The impact modifier is not particularly limited, and a conventionally known impact modifier can be used without particular limitation. Polybutadiene, polyisoprene, polychloroprene, chlorinated polyethylene, fluororubber, styrene- Butadiene-based copolymer rubber, methyl methacrylate-butadiene-styrene-based copolymer, methyl methacrylate-butadiene-styrene-based graft copolymer, acrylonitrile-styrene-butadiene-based copolymer rubber, acrylonitrile-styrene-butadiene-based graft Copolymer, styrene-butadiene-styrene block copolymer rubber, styrene-isoprene-styrene copolymer rubber, styrene-ethylene-butylene-styrene copolymer rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene Examples thereof include copolymer rubber (EPDM), silicone-containing acrylic rubber, silicone / acrylic composite rubber-based graft copolymer, and silicone-based rubber. Only one type of the impact modifier may be used, or two or more types may be used in combination.

The heat resistance improving agent is not particularly limited, and examples thereof include α-methylstyrene-based resins and N-phenylmaleimide-based resins. Only one kind of the heat resistance improving agent may be used, or two or more kinds thereof may be used in combination.

The antioxidant is not particularly limited, and a phenolic antioxidant such as 4,4'-butylidenebis- (6-t-butyl-3-methylphenol), tris (mixed mono and di-nonylphenyl) phos. Examples thereof include phosphite-based antioxidants such as phyto, and thioether-based antioxidants such as distearylthiodipropionate. Of these, phenolic antioxidants such as 4,4'-butylidenebis- (6-t-butyl-3-methylphenol), which has a low high-temperature decomposition inhibitory function, are particularly preferable. Only one type of the antioxidant may be used, or two or more types may be used in combination.

The ultraviolet absorber is not particularly limited, and examples thereof include a salicylic acid ester-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, and a cyanoacrylate-based ultraviolet absorber. Only one kind of the ultraviolet absorber may be used, or two or more kinds may be used in combination.

The antistatic agent is not particularly limited, and conventionally known antistatic agents can be used, and anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants and the like are used. I can do it. Anionic surfactants include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, aliphatic amines, amide sulfates, dibasic fatty acid ester sulfates, fatty acid amide sulfonates, and alkylaryls. Examples thereof include sulfonates, formalin-condensed naphthalene sulfonates, and mixtures thereof. Examples of the cationic surfactant include aliphatic amine salts, quaternary ammonium salts, alkylpyridium salts and mixtures thereof. Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol esters, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, and mixtures thereof. be able to. It may be a mixture of a nonionic surfactant and an anionic surfactant or a cationic surfactant. Examples of the amphoteric surfactant include an imidazoline type, a higher alkylamino type (betaine type), a sulfate ester, a phosphoric acid ester type, and a sulfonic acid type. Only one type of antistatic agent may be used, or two or more types may be used in combination.

The light stabilizer is not particularly limited, and examples thereof include hindered amine-based light stabilizers. Only one kind of the light stabilizer may be used, or two or more kinds thereof may be used in combination.

The filler is not particularly limited, and carbonates such as talc, heavy calcium carbonate, precipitated calcium carbonate, and collagen carbonate, aluminum hydroxide, magnesium hydroxide, titanium oxide, clay, mica, wollastonite, and zeolite. , Silica, zinc oxide, magnesium oxide, carbon black, graphite, glass beads, glass fibers, carbon fibers, metal fibers and other inorganic fibers, as well as organic fibers such as polyamide and the like. Only one kind of the filler may be used, or two or more kinds thereof may be used in combination.

The pigment is not particularly limited, and examples thereof include organic pigments and inorganic pigments. Examples of the organic pigment include an azo-based organic pigment, a phthalocyanine-based organic pigment, a slene-based organic pigment, and a dye lake-based organic pigment. Examples of the inorganic pigments include oxide-based inorganic pigments, molybdenum chromate-based inorganic pigments, sulfide / selenium-based inorganic pigments, and ferrosinized inorganic pigments. Only one kind of the pigment may be used, or two or more kinds thereof may be used in combination.

Examples of the flame retardant include metal hydroxides, brominated compounds, triazine ring-containing compounds, zinc compounds, phosphorus compounds, halogen flame retardants, silicone flame retardants, intomescent flame retardants, antimony oxide and the like. , These can be used alone or in combination of two or more.

The plasticizer may be added for the purpose of improving processability at the time of molding. The plasticizer is not particularly limited, and conventionally known plasticizers can be used. For example, phthalate ester plasticizers and non-phthalate plasticizers can be used. Examples of the phthalate ester plasticizer include dioctyl phthalate (DOP). Examples of non-phthalic acid-based plasticizers include trimellitic acid-based compounds, phosphoric acid-based compounds, adipic acid-based compounds, citric acid-based compounds, ether-based compounds, polyester-based compounds, soybean oil-based compounds, and cyclohexanedicarboxylate. Examples include system compounds and terephthalic acid compounds. Only one type of the plasticizer may be used, or two or more types may be used in combination.

The content of the plasticizer contained in the vinyl chloride resin composition (A) is preferably small because if it is contained in a large amount in the vinyl chloride resin composition (A), the mechanical strength of CFRP may be impaired. Specifically, the content of the plasticizer is 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 1 part by mass or less, and further, with respect to 100 parts by mass of the vinyl chloride resin. It is more preferably 0.1 part by mass or less, and most preferably it does not contain the plasticizer.

For example, when improvement in heat resistance and flame retardancy is expected, it is preferable to select a vinyl chloride resin containing a chlorinated vinyl chloride resin as a main component. In general, a chlorinated vinyl chloride resin composition has a higher melt viscosity than a vinyl chloride resin composition and is easily thermally decomposed, so that it is difficult to impregnate carbon fibers. Therefore, when a chlorinated vinyl chloride resin is used for the vinyl chloride resin composition (A), it is expected by using a chlorinated vinyl chloride resin having a low degree of polymerization or increasing the amount of additives added. A CFRP that maintains heat resistance and flame retardancy and mechanical properties can be obtained.

<Carbon fiber base material (B)>
The definitions of the carbon fiber and the carbon fiber base material in the present invention are shown below.
Carbon fiber is a fiber composed of a material containing carbon. It is a concept that includes the case of using it together with other fibers and the case of using it alone.
The carbon fiber base material is a carbon fiber woven fabric in which a carbon fiber bundle composed of a plurality of carbon fibers is used as a warp bundle and a weft bundle.
Carbon fiber is a concept including short carbon fiber, long carbon fiber, and continuous carbon fiber.
The short carbon fiber is a carbon fiber having a fiber length of 1 mm or less.
The long carbon fiber is a carbon fiber having a fiber length of 5 cm or less.
Continuous carbon fibers are carbon fibers other than short fibers and long fibers.

(Carbon fiber material)
The material of the carbon fiber is not particularly limited as long as it is a carbon fiber such as PAN (polyacrylonitrile) carbon fiber and pitch carbon fiber, and other fibers; metal fiber such as steel fiber; glass fiber, ceramic fiber, etc. Inorganic fibers such as boron fiber; and organic fibers such as aramid, polyester, polyethylene, nylon, vinylon, polyacetal, polyparaphenylene benzoxazole, and high-strength polypropylene; used in combination with natural fibers such as kenaf and hemp. May be done. From the viewpoint of specific strength, it is preferable that it is composed of only carbon fibers.

As the carbon fiber used in the present invention, short carbon fiber, long carbon fiber, and continuous carbon fiber can be appropriately used, but continuous carbon fiber is preferable from the viewpoint of mechanical properties of the obtained CFRP.

(Form and manufacturing method of carbon fiber base material (B))
The form of the fiber is not particularly limited as long as it is a continuous fiber, for example, a form in which the toe and the toe directions are aligned in one direction and held by a weft auxiliary thread, a form in which the fiber is used as a warp and a woven fabric (cross); Examples thereof include a form of a multi-axial warp knit in which a plurality of fiber sheets in which the directions of the above are aligned in one direction are woven and fastened with auxiliary threads so that the directions of the fibers are different from each other. The carbon fiber base material (B) can be obtained by producing the carbon fiber by each production method based on the above-mentioned form.

Each carbon fiber is generally a single fiber, and a plurality of carbon fibers are gathered to form a carbon fiber bundle. The number of carbon fibers constituting each carbon fiber bundle is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, and even more preferably 5,000 to 25,000.

The fiber diameter of the filament is preferably 3 μm or more, and preferably 12 μm or less. Sufficient strength can be obtained when the fiber diameter is 3 μm or more, and for example, when the filament causes lateral movement on the surface of a roll, spool, etc. in various processing processes, it suppresses cutting or fluffing. it can. The upper limit is usually about 12 μm because carbon fibers can be easily produced.

The plurality of carbon fiber bundles are not particularly limited, but are preferably in the form of a sheet. The basis weight of the sheet-shaped carbon fiber bundle is, for example, preferably 100 g / m ² or more and 600 g / m ² or less, and more preferably 150 g / m ² or more and 500 g / m ² or less. It is preferable that the basis weight is at least the above lower limit value because it is efficient when the obtained CFRP sheets are laminated and secondary processed, and at least the above upper limit value is easy to obtain impregnation property. It is preferable in that.

As the carbon fiber base material (B), it is preferable to use a carbon fiber bundle that has been pre-spread (hereinafter, may be referred to as a spread carbon fiber bundle) for the purpose of facilitating impregnation with the resin. The fiber opening step is not particularly limited, and examples thereof include a method of including spacer particles, a method of squeezing the fiber with a round bar, a method of using an air flow, a method of vibrating the fiber with ultrasonic waves, and the like. A method of including spacer particles is preferable, and by widening the interfiber distance in this way, even if a high tension is applied to the carbon fiber at the manufacturing stage, the interfiber distance is preliminarily widened. , Resin impregnation becomes easy. Further, even if tension is applied to the fibers, the distance between the fibers is unlikely to be narrowed.

The spacer particles penetrate between the carbon fibers in each fiber bundle, thereby opening the carbon fiber bundle. The spacer particles that have entered between the carbon fibers may be crosslinked between the carbon fibers. Here, "cross-linking" means having a structure in which spacer particles that have entered between carbon fibers are arranged so as to bridge at least two carbon fibers. Further, the spacer particles may be adhered to carbon fibers via carbon allotropes existing on the particle surface. By bridging the carbon fibers between the carbon fibers and adhering the spacer particles to the carbon fibers, it becomes easier to maintain the opened state of the fiber bundle more firmly.

The spacer particles are not particularly limited, but may contain, for example, carbon allotropes. In the spacer particles, carbon allotropes include, for example, amorphous carbon, graphite, diamond and the like. Amorphous carbon is mentioned as an amorphous carbon. Among these, amorphous carbon is preferable, and amorphous carbon is more preferable.

Here, the carbon allotrope is preferably derived from the carbon of the thermosetting resin, that is, the carbon allotrope is preferably obtained by carbonizing the thermosetting resin. Examples of the thermosetting resin include phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane, oxazine resin, etc., and strong amorphous carbon by carbonization treatment at low temperature. Oxazine-based resin is preferable from the viewpoint of forming a film of. Examples of the oxazine-based resin include benzoxazine resin and naphthoxazine resin. Among these, the naphthoxazine resin is preferable from the viewpoint that it is easily carbonized at a lower temperature, and it is difficult to be excessively softened even under the temperature and pressure conditions at the time of CFRP production of the present invention. Therefore, a sufficient distance between fibers is secured, and the impregnation property of the resin is further improved.

Further, the spacer particles may be carbon allotrope particles composed of carbon allotropes, but may be film particles containing core particles and carbon allotropes that coat the core particles. The spacer particles are preferably coated particles from the viewpoint of resin impregnation. The entire surface of the coated particles may be coated with a carbon allotrope, or a part of the surface thereof may be coated with a carbon allotrope. The core particles can be used without particular limitation as long as they are not deformed or destroyed by the pressure and temperature when the carbon fiber bundle is impregnated with the thermoplastic resin. For example, inorganic particles, organic particles and the like can be used. it can. As the core particles, inorganic particles or organic particles may be used alone, or both may be used in combination.

The average particle size of the spacer particles is preferably 1 to 20 μm. By using the spacer particles having a size in this range, the spacer particles can be easily inserted between the carbon fibers, and the carbon fiber bundle can be opened more widely. The more preferable average particle size of the spacer particles is 2 to 20 μm, and particularly preferably 4 to 15 μm.

The total amount of spacer particles adhered to the spread-treated carbon fiber bundle is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, based on the spread carbon fiber bundle. By setting the adhesion amount to the lower limit value or more, the carbon fiber bundle can be appropriately opened. Further, by setting the adhesion amount to the upper limit value or less, it is possible to prevent the spread carbon fiber bundle from containing spacer particles more than necessary and deteriorating the mechanical properties.

[Manufacturing method of carbon fiber reinforced composite material]
As an example, the carbon fiber reinforced composite material according to the present invention can be produced by a method including (1) a base material preparation step and (2) a resin impregnation step. Hereinafter, each step will be described in detail.

(1) Base material preparation step (1) The base material preparation step is a step of preparing the carbon fiber base material (B) described above. The carbon fiber base material (B) is as described above, and for example, an appropriate carbon fiber material, form, and basis weight can be selected. Further, a woven fabric having a desired structure may be produced by using a commercially available carbon fiber bundle.

The preparation step of the carbon fiber base material preferably includes a step of opening the carbon fiber bundle. Hereinafter, the step of opening the carbon fiber bundle will be described. Various methods can be considered for opening the carbon fiber bundle, and as an example, the carbon fiber bundle may include spacer particles arranged between the carbon fibers. By arranging the spacer particles between the carbon fibers, the carbon fiber bundle is opened and the thermoplastic resin can be sufficiently impregnated into the carbon fiber woven fabric. In addition, when a treatment such as physical opening of fibers is performed, the fiber bundles are laterally opened, the pitch width of the woven fabric is increased, and the design of the fiber-reinforced composite material may be deteriorated. Since the carbon fiber woven fabric composed of carbon fiber bundles having spacer particles on the surface of the carbon fiber as described above is not physically opened, it is possible to suppress deterioration of the design of the fiber reinforced composite material. It is considered that the impregnation property of the thermoplastic resin can be improved because the carbon fiber bundles are sufficiently opened by the spacer particles.

The spread carbon fiber bundle can be produced by bringing the carbon fiber bundle into contact with the spread fiber impregnating liquid and heating it. After opening the carbon fiber bundle, the carbon fiber woven fabric may be obtained by using the opened defibrated carbon fiber bundle, but after producing the carbon fiber woven fabric using the carbon fiber bundle, the carbon fiber bundle is opened by the above method. It is preferable to fiber.

The timing of contacting the carbon fiber bundle with the opening fiber impregnating liquid may be such that the carbon fiber bundle is brought into contact with the opening fiber impregnating liquid in advance before the carbon fiber fabric is produced, and the carbon fiber bundle is used as a warp yarn bundle and a weft yarn bundle. The carbon fiber woven fabric may be woven and the obtained carbon fiber woven fabric may be brought into contact with the opening fiber impregnating liquid to open the carbon fiber bundle.

The contact of the opening fiber impregnating liquid may be performed by impregnating the carbon fiber bundle with the opening fiber impregnating liquid. Specifically, the spread fiber impregnating liquid may be sprayed or applied to the carbon fiber bundle, or the carbon fiber bundle may be immersed in the fiber spread impregnated liquid. By bringing the carbon fiber bundles into contact with the opening fiber impregnating liquid, the resin particles enter the gaps between the carbon fibers of the carbon fiber bundles, whereby the carbon fiber bundles can be opened.

The opening fiber impregnating liquid used for opening the carbon fiber bundle contains a monomer (hereinafter, also simply referred to as “monomer”) capable of forming a thermosetting resin. The monomer reacts to become a thermosetting resin. The thermosetting resin is preferably an oxazine-based resin as described above, but when the thermosetting resin is an oxazine-based resin, the monomers are, for example, phenols, formaldehyde, and amines. As the oxazine-based resin, as described above, a naphthoxazine resin is preferable.

(2) Resin impregnation step (2) The resin impregnation step is a step of impregnating the carbon fiber base material (B) prepared above with the vinyl chloride resin composition (A). The carbon fiber reinforced composite material according to the present invention can be produced by impregnating the carbon fiber woven fabric composed of the above-mentioned spread carbon fiber bundle with the vinyl chloride resin composition (A).

For example, a film made of a vinyl chloride resin composition (A) is laminated on a carbon fiber base material (B) composed of open fiber carbon fiber bundles and heat-press molded, or on the carbon fiber base material (B). The carbon fiber base material (B) can be impregnated with the vinyl chloride resin composition (A) by performing melt extrusion molding of the vinyl chloride resin composition (A). As the carbon fiber reinforced composite material, a plurality of carbon fiber base materials (B) impregnated with the vinyl chloride resin composition (A) may be laminated, and at this time, the structure direction of each carbon fiber woven fabric is at a constant angle. By superimposing the carbon fiber base materials (B) so as to be displaced, a carbon fiber reinforced composite material having further excellent mechanical strength can be obtained.

Extrusion molding or press molding can be used for the hot press, and a carbon fiber reinforced composite material having a desired shape can be obtained by using a molding die. The temperature at which the hot press molding is performed can be set to a temperature higher than the temperature at which the vinyl chloride resin composition (A) to be used softens or melts.

(Bending strength)
The carbon fiber reinforced composite material according to the present invention has good bending strength. For example, when the fiber volume fraction (Vf) of the carbon fiber reinforced composite material is 50 ± 2%, the bending strength of the three-point bending test is preferably 300 MPa or more, more preferably 400 MPa or more, and 500 MPa or more. It is more preferable to have. When the bending strength is at least the above lower limit value, it can be suitably used in applications requiring high strength such as aircraft structural members, wind turbine blades, and automobile outer panels. The three-point bending test conforms to JIS K 7074, and the distance between fulcrums (L) is (L) for a test piece having a length (l) of 40 ± 1 mm, a width (b) of 15 ± 0.2 mm, and a thickness of h. Is a measured value (MPa) with 40 × hmm. The jig indenter radius of the bending test was 5 mm, and the indenter width was 2 mm.

(Calculation of fiber volume fraction Vf)
The calculation of the fiber volume fraction (Vf) of the carbon fiber reinforced composite material according to the present invention was calculated as follows.
Vf (%) = 100 x carbon fiber thickness (mm) ÷ carbon fiber reinforced composite material thickness (mm)

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.

<Making resin film>
Vinyl chloride resin 1 (manufactured by Tokuyama Sekisui Kogyo, SL-P40, degree of polymerization of about 400) was dissolved in tetrahydrofuran so as to have a solution concentration of about 10%. Subsequently, 0.5 parts by mass of a heat stabilizer 1 (methyl tin mercapto, liquid stabilizer, manufactured by Nitto Kasei Co., Ltd .: AT5300) was added to the solution to 100 parts by mass of the vinyl chloride resin as an additive. The mixture was stirred to obtain a vinyl chloride resin composition (A). The obtained vinyl chloride resin composition (A) was coated on a glass plate with a solution using a glass rod, and allowed to stand to volatilize the solvent to obtain a resin film. After the obtained resin film was peeled off from the glass plate, it was further dried in a traveling oven at 60 ° C. for about 3 hours to obtain a resin film for producing CFRP.

<Creation of carbon fiber base material (B)>
A monomer consisting of 10 parts by mass of 1,5-dihydroxynaphthalene, 4 parts by mass of a 40% by mass methylamine aqueous solution, and 8 parts by mass of formalin (formaldehyde content: 37% by mass), and ethanol water (ethanol content: ethanol content:) as a solvent. 50 parts by mass) 800 parts by mass was uniformly mixed to prepare a monomer solution prepared by dissolving the monomer. Next, 10 parts by mass of particles made of divinylbenzene crosslinked polymer (manufactured by Sekisui Chemical Industry Co., Ltd., trade name "Micropearl SP", average particle size 10 μm) were added to the above monomer solution to prepare an open fiber impregnated solution. ..

Subsequently, a carbon fiber woven fabric composed of PAN-based carbon fiber bundles (number of carbon fibers: 3000, average diameter of carbon fibers: 7 μm, grain: 200 g / m ² , thickness: 0.19 mm, plain weave) was prepared. The carbon fiber woven fabric was immersed in the above-mentioned opening fiber impregnating solution, pulled up, and then heated at 200 ° C. for 2 minutes. By this heating, the polymerization reaction of the naphthoxazine resin and carbonization occurred, and amorphous carbon derived from the naphthoxazine resin was produced, and a woven fabric of open fiber bundles was obtained. The total amount of organic particles and carbon allotropes attached to the spread carbon fiber bundle was 1% by mass. This spread carbon fiber bundle was used as a carbon fiber base material (B).

(Example 1)
<Press molding of CFRP>
The carbon fiber base material (B) obtained above is sandwiched between the two resin films obtained above from above and below, pressed stepwise from 0 to 6 MPa at 200 ° C., and pressed for a total of about 10 minutes. This gave CFRP. The obtained CFRP was used as a sample "fruit-1" for physical property evaluation.

(Example 2)
CFRP was obtained by the same process as in Example 1 except that the amount of the heat stabilizer 1 was increased to 2 parts by mass in the preparation of the resin film. The obtained CFRP was used as a sample “Actual-2” for physical property evaluation.

(Example 3)
CFRP was obtained by the same process as in Example 1 except that the amount of the heat stabilizer 1 was increased to 10 parts by mass in the preparation of the resin film. The obtained CFRP was used as a sample “Actual-3” for physical property evaluation.

(Example 4)
CFRP was obtained by the same process as in Example 1 except that the amount of the heat stabilizer 1 was increased to 20 parts by mass in the preparation of the resin film. The obtained CFRP was used as a sample “Actual-4” for physical property evaluation.

(Example 5)
In the preparation of the resin film, the same process as in Example 1 except that the heat stabilizer 1 was changed to the heat stabilizer 2 (octyl tin mercapto, liquid stabilizer, manufactured by Nitto Kasei Co., Ltd., KK6476) and 10 parts by mass was added. Obtained CFRP. The obtained CFRP was used as a sample “Actual-5” for evaluation of physical properties.

(Example 6)
CFRP was obtained by the same process as in Example 2 except that the vinyl chloride resin 1 was changed to the vinyl chloride resin 2 (manufactured by Tokuyama Sekisui Kogyo Co., Ltd., TS-640M, degree of polymerization of about 640) in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-6" for physical property evaluation.

(Example 7)
CFRP was obtained by the same process as in Example 2 except that 0.5 parts by mass of external lubricant 1 (HIWAX220RKT polyethylene wax manufactured by Mitsui Chemicals, Inc.) was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-7" for physical property evaluation.

(Example 8)
CFRP was obtained by the same process as in Example 2 except that 2 parts by mass of the external lubricant 1 was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-8" for physical property evaluation.

(Example 9)
CFRP was obtained by the same process as in Example 2 except that 5 parts by mass of the external lubricant 1 was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-9" for physical property evaluation.

(Example 10)
CFRP was obtained by the same process as in Example 2 except that 5 parts by mass of external lubricant 2 (AC316 polyethylene oxide wax manufactured by Honeywell Co., Ltd.) was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-10" for physical property evaluation.

(Example 11)
CFRP was obtained by the same process as in Example 2 except that 5 parts by mass of external lubricant 3 (SG22 ester wax manufactured by RIKEN Vitamin Co., Ltd.) was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-11" for physical property evaluation.

(Example 12)
CFRP was obtained by the same process as in Example 2 except that 10 parts by mass of internal lubricant 1 (LOXIOL G60 glycerin monostearate manufactured by Emery Oleo Chemical Co., Ltd.) was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-12" for physical property evaluation.

(Example 13)
CFRP was obtained by the same process as in Example 2 except that 0.1 part by mass of plasticizer 1 (dioctylphthalate manufactured by J-PLUS Co., Ltd.) was added in the preparation of the resin film. The obtained CFRP was used as a carbon fiber base material sample "Fruit-13" for physical property evaluation.

(Comparative Example 1)
CFRP was obtained by the same process as in Example 2 except that 25 parts by mass of the internal lubricant 1 was added in the preparation of the resin film. The obtained CFRP was used as a sample "ratio-1" for evaluation of physical properties.

(Comparative Example 2)
The same as in Example 2 except that vinyl chloride resin 3 (TS-1000R manufactured by Tokuyama Sekisui Kogyo Co., Ltd., degree of polymerization of about 1000 (high degree of polymerization)) was used instead of vinyl chloride resin 1 in the preparation of the resin film. CFRP was obtained by the process. The obtained CFRP was used as a carbon fiber base material sample “ratio-2” for physical property evaluation.

(Comparative Example 3)
CFRP was obtained by the same process as in Example 1 except that 30 parts by mass of plasticizer 1 was added in the preparation of the resin film. The obtained CFRP was used as a sample "ratio-3" for physical property evaluation.

<Preparation of sample for viscosity measurement>
The prepared resin film made of the vinyl chloride resin composition (A) is cut into a size of 30 (mm) × 90 (mm), weighed to about 5 g, and heated at 170 ° C. for about 3 minutes. A sample for measuring viscosity having a thickness of 1 mm was prepared by press molding and cooling for about 1 minute.

<Measurement of complex viscosity η>
The complex viscosity η of the vinyl chloride resin composition (A) used for producing the resin film was measured by the following method. The measurement results are shown in Table 1.
A viscoelasticity measuring device (manufactured by MCR102 Antonio Par) was used for the measurement, and the diameter of the parallel plate was measured under the conditions of 25 mm, the parallel distance of 1 mm, the temperature of 200 ° C., and the angular frequency of 10 Hz, and the complex viscosity η was calculated.

<Measurement of bending strength>
From the samples "Fruit-1" to "Fruit-5" and "Ratio-1" to "Ratio-4" prepared above, the measurement sample conforms to JIS K 7074, and the length (l) is 40 ± 1 mm. A test piece having a width (b) of 15 ± 0.2 mm and a thickness of h was prepared by setting the distance between fulcrums (L) to 40 × h (mm). The bending strength (MPa) of the prepared test piece was measured by a three-point bending method using a testing machine (AUTOGRAPH AGS-H manufactured by SHIMADZU). The measurement results are shown in Table 1.

(Calculation of bending strength of Vf 50%)
Measure the bending strength of a sample with Vf in the range of 50 ± 2% at N = 3 or more, perform linear approximation from the measured value, calculate the bending strength at Vf 50%, and evaluate according to the following evaluation criteria. It was. The evaluation results are shown in Table 1.
(Evaluation criteria)
400 MPa or more: ○
300 MPa or more and less than 400 MPa: Δ
Less than 300 MPa: ×

Claims (8)

A carbon fiber reinforced composite material composed of a vinyl chloride resin composition (A) and a carbon fiber base material (B).
The vinyl chloride resin composition (A) contains a vinyl chloride resin and at least one additive.
The vinyl chloride resin composition (A) has a complex viscosity η at 200 ° C. and a frequency of 10 Hz of 1 <η <1500.
The average degree of polymerization of the vinyl chloride resin is 400 or more and 1500 or less.
In the vinyl chloride resin composition (A), the content of the heat stabilizer is 0.1 to 30 parts by mass and the content of the internal lubricant is 20 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The following, a carbon fiber reinforced composite material, characterized in that the external lubricant is 10 parts by mass or less and the content of the plasticizer is 10 parts by mass or less. The carbon fiber reinforced composite material according to claim 1, wherein the vinyl chloride resin composition (A) has a complex viscosity η at 200 ° C. and a frequency of 10 Hz of 10 <η <1000. The heat stabilizer is at least one selected from the group consisting of organic tin stabilizers, lead stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, and barium-cadmium stabilizers. , The carbon fiber reinforced composite material according to claim 1 or 2. Any of claims 1 to 3, wherein the internal lubricant is at least one selected from the group consisting of butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide. The carbon fiber reinforced composite material according to item 1. The carbon fiber reinforced composite material according to any one of claims 1 to 4, wherein the external lubricant is at least one selected from the group consisting of paraffin wax, polyolefin wax, ester wax, and montanic acid wax. The item according to any one of claims 1 to 5, wherein in the vinyl chloride resin composition (A), the total content of the additives is 70 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin. The carbon fiber reinforced composite material described. The carbon fiber according to any one of claims 1 to 6, wherein the average bending strength of the three-point bending test is 300 MPa or more when the fiber volume fraction (Vf) of the carbon fiber reinforced composite material is 50 ± 2%. Reinforced composite material. A molded product made of the carbon fiber reinforced composite material according to any one of claims 1 to 7.