JP2020041253A - Polycarbonate fiber, production method of the same, sheet for fiber-reinforced plastic including the same, and fiber-reinforced plastic - Google Patents

Abstract

To provide a polycarbonate fiber that has good spinnability, has a fiber treatment agent hardly causing the deterioration of a polycarbonate resin adhered to a fiber surface and has good process property and a production method of the polycarbonate fiber, to provide a sheet for fiber-reinforced plastic including the polycarbonate fiber and to provide fiber-reinforced plastic.SOLUTION: The polycarbonate fiber includes 50 mass% or more of a polycarbonate resin, has a fiber treatment agent adhered in a ratio of 0.05 pt.mass to 3 pts.mass per 100 pts.mass of the polycarbonate fiber to the surface of the polycarbonate fiber. The fiber treatment agent includes 70 mass% or more of at least one kind of anionic surfactant selected from the group consisting of an alkyl phosphate and a polyoxyethylene alkyl ether phosphate.SELECTED DRAWING: None

Description

  The present invention relates to a polycarbonate fiber containing a polycarbonate resin and having a fiber treating agent containing a specific component adhered to a surface thereof, a method for producing the same, a sheet for a fiber-reinforced plastic containing the same, and a fiber-reinforced plastic.

  Polycarbonate resins have excellent mechanical properties and are therefore used as matrix phases in fiber-reinforced plastic materials. For example, Patent Documents 1 and 2 propose fiber-reinforced plastic materials using a polycarbonate resin composition containing a polycarbonate resin and glass fibers.

When press-molding the polycarbonate resin compositions described in Patent Documents 1 and 2 to obtain a fiber-reinforced plastic material, there is a problem that handleability is poor. Therefore, in order to improve the handleability at the time of molding, it has been practiced to mix a reinforcing fiber and a polycarbonate fiber serving as a matrix resin to obtain a molding base for a fiber-reinforced plastic. For example, Patent Document 3, and the reinforcing fibers, melt volume flow rate is 18cm ^3/10 minutes fiber-reinforced plastic molding substrate for a polycarbonate resin with a fiber obtained by cutting the melt-spun filaments are To obtain a fiber reinforced plastic. Further, Patent Document 4 discloses a polycarbonate multifilament yarn for a matrix phase resin of a molded product, in which a birefringence and a breaking elongation satisfy specific ranges.

Patent No. 5275689 JP 2014-129489 A JP 2014-51555 A JP-A-04-146210

However, the polycarbonate resin melt volume flow rate described in Patent Document 3 is a 18cm ^3/10 minutes, since the molecular weight is high, there is a problem that the spinnability is poor. Patent Document 4 discloses that a fiber treatment agent (generally also referred to as an oil agent) does not adhere to or adhere to a polycarbonate multifilament yarn serving as a matrix resin of a fiber-reinforced plastic molded product. Although it discloses that a fiber treatment agent that is easy to fall off is preferable, but in consideration of processability such as card passing property and dispersibility in a paper making process, even if it adheres to the surface of the polycarbonate fiber for a long time, polycarbonate There is a demand for using a fiber treatment agent that hardly affects the resin.

  The present invention solves the above-mentioned conventional problems, and has a good spinnability, a fiber treatment agent which hardly degrades the polycarbonate resin is adhered to the fiber surface, and has good processability, a polycarbonate fiber having good processability, and a method for producing the same. Provided are a sheet for a fiber-reinforced plastic, and a fiber-reinforced plastic.

  The present invention is a polycarbonate fiber containing 50% by mass or more of a polycarbonate resin, and a fiber treatment agent adheres to the surface of the polycarbonate fiber at a ratio of 0.05 to 3 parts by mass per 100 parts by mass of the polycarbonate fiber. Wherein the fiber treating agent contains at least 70% by mass of one or more anionic surfactants selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl ether phosphates. It relates to polycarbonate fibers.

  The present invention is also a method for producing a polycarbonate fiber, wherein the number average molecular weight (Mn) before spinning is 9000 or more and 16000 or less, and the weight average molecular weight (Mw) before spinning is 22000 or more and 36000 or less, or A step of preparing a mixture containing 50% by mass or more of the polycarbonate resin, a step of melt-spinning a resin component containing 50% by mass or more of the polycarbonate resin at a temperature of 250 ° C. or more and 350 ° C. or less, and forming a spun filament; A step of adhering a fiber treating agent to the fiber surface at a ratio of 0.05 to 3 parts by mass per 100 parts by mass of the polycarbonate fiber, wherein the fiber treating agent is an alkyl phosphate ester salt and a polyoxyethylene. Selected from the group consisting of alkyl ether phosphates Characterized in that it comprises one or more anionic surface active agent 70% by mass or more, a method for producing a polycarbonate fibers.

  The present invention is also a sheet for a fiber-reinforced plastic containing the above-mentioned polycarbonate fiber and a reinforcing fiber, wherein the fiber-reinforced plastic sheet has a fiber reinforced plastic content of 100% by mass. The present invention relates to a sheet for a fiber-reinforced plastic, comprising 23.5% by mass to 80% by mass and 20% by mass to 76.5% by mass of polycarbonate fibers.

  The present invention is also a fiber-reinforced plastic containing a reinforcing fiber and a matrix resin, wherein the fiber-reinforced plastic has a reinforcing fiber content of 22% by volume or more and 75% by volume or less when the volume of the fiber-reinforced plastic is 100% by volume. Wherein the matrix resin is obtained by melting the polycarbonate fibers, and contains 50% by mass or more of the polycarbonate resin.

  According to the present invention, good spinnability, a fiber treatment agent that hardly degrades the polycarbonate resin is attached to the fiber surface, the processability is good polycarbonate fiber and a method for producing the same, and a sheet for fiber-reinforced plastic containing the same, In addition, a fiber-reinforced plastic can be provided.

  The present inventors have improved the spinnability of the polycarbonate fiber, and without causing deterioration of the polycarbonate resin, the cardability of the polycarbonate fiber and the fiber web forming property when producing an air-laid nonwoven fabric, and the dispersion in the papermaking process during the production of a wet nonwoven fabric. We studied diligently to improve the processability such as the processability. As a result, in a polycarbonate fiber containing 50% by mass or more of a polycarbonate resin, at least one anionic surfactant selected from the group consisting of an alkyl phosphate salt and a polyoxyethylene alkyl ether phosphate is provided on the surface of the polycarbonate fiber. By depositing a predetermined amount of a fiber treating agent containing 70% by mass or more, it has been found that the processability is improved and that the fiber treating agent is unlikely to deteriorate the polycarbonate resin.

  When the above-mentioned polycarbonate fiber is used as a matrix phase (matrix resin) of a fiber-reinforced plastic, specifically, a matrix phase obtained by heating and pressing a sheet for a fiber-reinforced plastic containing the polycarbonate fiber and the reinforcement fiber is obtained. In a fiber reinforced plastic composed of a polycarbonate resin, by melting a polycarbonate fiber having the fiber treatment agent described above attached to the fiber surface to form a matrix phase, deterioration of the polycarbonate resin is suppressed, and the obtained fiber reinforced It has been found that the mechanical properties of plastics are improved. Therefore, the polycarbonate fiber can be suitably used for a fiber-reinforced plastic, and in the fiber-reinforced plastic, the polycarbonate fiber is melted to be a matrix phase.

  From the viewpoint of enhancing spinnability and strength, the polycarbonate fiber preferably contains 60% by mass or more of a polycarbonate resin, more preferably 70% by mass or more, further preferably 75% by mass or more, and more preferably 80% by mass or more. It is particularly preferred to include. The upper limit of the ratio of the polycarbonate resin contained in the polycarbonate fiber is not particularly limited, and may be substantially composed of a polycarbonate resin satisfying the melt flow rate. Here, the term "substantially" means that the resin provided as a product usually contains additives such as stabilizers and / or various additives are added during the production of fibers, and thus the polycarbonate resin It is used in consideration of the fact that a fiber consisting of only the other components and containing no other components cannot be obtained. In the polycarbonate fiber, the content of components other than the polycarbonate resin is preferably 30% by mass or less. Examples of the other components include other resin components and additives. Examples of the other resin component include olefin-based polymers such as polypropylene, polyethylene, polybutene, and polymethylpentene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; and homopolymers and copolymers such as polyamides such as nylon 6; , Polystyrene resin, acrylonitrile-styrene (AS) resin, acrylonitrile-butadiene-styrene (ABS) resin, and the like. Examples of the additives include antistatic agents, pigments, matting agents, heat stabilizers, light stabilizers, flame retardants, antibacterial agents, lubricants, plasticizers, softeners, antioxidants, ultraviolet absorbers, and crystal nuclei. Agents and the like.

  The polycarbonate fiber of the present invention preferably contains a flame retardant as an additive. Polycarbonate resin is a highly flame-retardant resin among thermoplastic resins, and has self-extinguishing properties. By adding an appropriate amount of the optimal flame retardant to the polycarbonate resin, the flame retardancy becomes even higher. A fiber-reinforced plastic product using a polycarbonate resin as a matrix phase can be preferably used for applications requiring flame retardancy. Applications requiring high flame retardancy include, for example, housings and reinforcing materials for electric and electronic devices (more specifically, OA devices, mobile phones, smartphones, personal digital assistants, tablet PCs, digital video cameras, etc.). Reinforcement materials such as ribs that are attached to and partially reinforce the housing of portable electronic devices such as air conditioners and household electrical appliances, and the housings of various electronic devices.); Various vehicles such as automobiles, motorcycles, and railway vehicles Structural parts (more specifically, outer frames or body parts such as various frames, beams, doors, trunk lids, side panels, upper back panels, front bodies, under bodies, and various pillars of automobiles and motorcycles, and their reinforcements) Materials, instrument panels, interior parts such as seat frames, gasoline tanks, hydrogen in vehicles equipped with fuel cells Fuel system, exhaust system, intake system parts such as tanks, various pipes and various valves, seat members for rail cars, outer panels, reinforcing materials to be attached to the outer panels, ceiling panels, etc.); Parts for aircraft (for example, parts such as winglets, spoilers, etc.); Construction members for civil engineering and building materials (for example, construction members such as various columns, panels, reinforcing materials, etc.). The polycarbonate fiber of the present invention and a fiber-reinforced plastic produced using the same are preferably used for the above-mentioned applications.

  The flame retardant that can be added to the polycarbonate resin constituting the polycarbonate fiber of the present invention is not particularly limited, and various flame retardants can be added to the polycarbonate resin. Examples of the flame retardant include organic phosphorus compounds, halogen organic compounds, silicone compounds, nitrogen-containing organic compounds such as melamine, inorganic compounds such as magnesium hydroxide and aluminum hydroxide, antimony oxide, bismuth oxide, and zinc oxide. , Tin oxide and other metal oxides, inorganic phosphorus compounds such as red phosphorus, phosphine, hypophosphorous acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, phosphoric anhydride, carbon fiber, glass fiber, and other fibers, expansion Graphite, silica, a silica-based glass melt, or the like is used, preferably one or more selected from the group consisting of a halogen-based organic compound, an organic phosphorus-based compound, and a silicone-based compound, and more preferably an organic phosphorus-based compound The use of condensed phosphoric esters, which are flame retardants for compounds.

(Condensed phosphate ester)
The condensed phosphate ester is a reaction product of a phosphorus halide (for example, phosphorus oxychloride), a polyhydroxyl compound (for example, a divalent phenol compound), and a hydroxyl compound (for example, phenol (or alkylphenol)). is there. Examples of the condensed phosphate include pentaerythritol diphosphate, resorcinol bis-diphenyl phosphate (RDP), resorcinol bis-dixylenyl phosphate (RDX), and bisphenol A bis-diphenyl phosphate (BDP). The condensed phosphoric ester may contain a halogen. Preferably, a halogen-free non-halogen condensed phosphoric acid ester containing no halogen is used from the viewpoint of environmental impact.

  The condensed phosphoric acid ester is preferably solid at room temperature (25 ° C.). If it is gaseous or liquid at normal temperature, the condensed phosphoric acid ester contained in the fiber may volatilize or exude from the fiber surface.

  As the condensed phosphate ester, those having a number average molecular weight of 200 or more and 2000 or less are preferably used. A mixture containing 5% by mass to 30% by mass of a condensed phosphate ester having a number average molecular weight of 200% or more and 2000% or less and 60% by mass or more of a polycarbonate resin has improved spinnability, and the obtained polycarbonate fiber has sufficient flame retardancy. Demonstrate. The ratio of the condensed phosphoric ester is selected according to the type of the polycarbonate resin to be mixed with the condensed phosphoric ester and the fineness of the fiber to be finally obtained. The condensed phosphoric acid ester may be 5% by mass or more and 30% by mass or less of the total mass of the condensed phosphoric acid ester, the polycarbonate resin, and the mixture with other resins and other additives mixed as necessary. The content is more preferably from 8% by weight to 25% by weight, particularly preferably from 10% by weight to 20% by weight, and most preferably from 11% by weight to 16% by weight. When the proportion of the condensed phosphoric acid ester is small, there is a possibility that the polycarbonate fiber and the fiber aggregate and the fiber-reinforced plastic produced using the same may not exhibit sufficient flame retardancy. When the proportion of the condensed phosphate ester exceeds 30% by mass, the fluidity of the polycarbonate resin containing the condensed phosphate ester at the time of melting becomes extremely high due to the influence of the condensed phosphate ester, and melt spinning may be difficult. .

  From the viewpoint of good spinnability, the polycarbonate resin preferably has a number average molecular weight (Mn) of 9000 or more and 16000 or less measured before and after melt spinning. When the number average molecular weight of the polycarbonate resin satisfies the above range, the flowability when the polycarbonate resin is melted becomes good, not only can be easily melt-spun, but also a fiber-reinforced plastic using the polycarbonate fiber of the present invention. During production, a polycarbonate resin in a molten state obtained by melting the polycarbonate fiber shows high fluidity. As a result, the molten polycarbonate resin easily impregnates even small gaps formed between the reinforcing fibers, so that cavities hardly remain inside the obtained fiber reinforced plastic, and mechanical properties such as impact resistance and bending strength are reduced. Characteristic is easily improved. Furthermore, a fiber reinforced plastic having sufficient mechanical strength can be obtained even if the conditions of heating and pressurizing during production are lower and lower. Spinnability, fluidity when melted, when used as a fiber that becomes a matrix phase of fiber reinforced plastic, from the viewpoint of further increasing the mechanical strength of the fiber reinforced plastic, the polycarbonate resin is measured before and after melt spinning. The number average molecular weight (Mn) is more preferably 15500 or less. Further, the lower limit of the number average molecular weight measured before and after melt spinning of the polycarbonate resin is more preferably 10,000 or more, particularly preferably 11,000 or more, from the viewpoint of easy availability and cost reduction. , 11500 or more.

  From the viewpoint of good spinnability, the polycarbonate resin preferably has a weight average molecular weight (Mw) of 22,000 to 36,000 measured before and after melt spinning. When the weight average molecular weight of the polycarbonate resin satisfies the above range, the flowability when the polycarbonate resin is melted is improved, and not only can the fiber be easily melt-spun, but also a fiber-reinforced plastic using the polycarbonate fiber of the present invention. During production, a polycarbonate resin in a molten state obtained by melting the polycarbonate fiber shows high fluidity. As a result, the molten polycarbonate resin easily impregnates even small gaps formed between the reinforcing fibers, so that cavities hardly remain inside the obtained fiber reinforced plastic, and mechanical properties such as impact resistance and bending strength are reduced. Characteristic is easily improved. Furthermore, a fiber reinforced plastic having sufficient mechanical strength can be obtained even if the conditions of heating and pressurizing during production are lower and lower. From the viewpoint of further improving the mechanical strength of the fiber reinforced plastic when used as a fiber that becomes a matrix phase of the fiber reinforced plastic, the weight average molecular weight measured before and after melt spinning ( Mw) is more preferably 35,000 or less, particularly preferably 34,500 or less, and most preferably 34,000 or less. The weight average molecular weight (Mw) of the polycarbonate resin measured before melt spinning and after melt spinning is more preferably 25,000 or more, particularly preferably 26,000 or more, from the viewpoint of easy availability and cost reduction. It is preferable that it is 27,000 or more.

  Since the polycarbonate resin has a number average molecular weight (Mn) measured after melt spinning of 9000 or more and 16,000 or less, the mechanical properties of a fiber-reinforced plastic manufactured using the fiber are improved, and the fiber-reinforced plastic is manufactured. In this case, the impregnation of the molten polycarbonate resin between the reinforcing fibers can be enhanced. In addition, from the viewpoint of easily obtaining the polycarbonate resin and reducing the cost, the number average molecular weight (Mn) of the polycarbonate resin measured after melt spinning is preferably 10,000 or more and 15,000 or less, more preferably 10500 or more and 14,000 or less. Is more preferable, and it is especially preferable that it is 11000 or more and 13500 or less.

  Since the polycarbonate resin has a weight average molecular weight (Mw) of 22,000 or more and 32,000 or less measured after melt spinning, the mechanical properties of a fiber-reinforced plastic produced using the fiber are improved, and the fiber-reinforced plastic is produced. In this case, the impregnation of the molten polycarbonate resin between the reinforcing fibers can be enhanced. In addition, the weight average molecular weight measured after melt spinning of the polycarbonate resin is easy to obtain the polycarbonate resin, reducing the cost, and from the viewpoint of increasing the mechanical strength of the fiber-reinforced plastic material using the obtained polycarbonate fiber, It is preferably from 24,000 to 31,000, more preferably from 26,000 to 30,000, particularly preferably from 26500 to 29500.

  In one embodiment of the present invention, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the resin pellets as the raw materials and the polycarbonate resin contained in the polycarbonate fiber obtained by melt spinning are determined by using a gel permeation chromatograph. It can be measured using: For example, a sample (polycarbonate resin or polycarbonate fiber) is added to tetrahydrofuran (THF) and dissolved by gentle stirring. Next, the solution in which the sample is dissolved is filtered with a filter to obtain a measurement sample solution. 100 μL of a sample solution for measurement is injected into a gel permeation chromatograph GPC (gel permeation chromatography), and the number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured. As a detector, a gel permeation chromatograph equipped with a differential refractive index (RI) detector (“HLC-8220GPC” manufactured by Tosoh Corporation) or the like can be used. Then, KF-G (1), KF-805L (2) and KF-800D (1) of Shodex (registered trademark) manufactured by Showa Denko KK were used as columns, and monodisperse polystyrene was used as a standard sample. And the temperature of the column thermostat can be measured at 40 ° C.

  The polycarbonate resin preferably has a melt flow rate (MFR; measured temperature: 300 ° C., load: 1.2 kgf) measured according to ISO 1133 of 40 g / 10 minutes or more. When the melt flow rate of the polycarbonate resin satisfies the above range, not only the spinnability of the polycarbonate fiber is enhanced, but also mechanical properties such as impact resistance of the fiber reinforced plastic containing the molten polycarbonate fiber as a matrix phase. Is easily improved. The polycarbonate resin preferably has an MFR of 45 g / 10 min or more, more preferably 50 g / 10 min or more, and particularly preferably 52 g / 10 min, from the viewpoint that the impregnation of the polycarbonate resin between the reinforcing fibers is enhanced. Most preferably, it is at least minutes. In the polycarbonate resin, the upper limit of the MFR is not particularly limited, but is preferably 140 g / 10 minutes or less from the viewpoint that the fluidity of the polycarbonate resin becomes too high and the mechanical properties of the obtained fiber-reinforced plastic, It is more preferably at most 125 g / 10 min, particularly preferably at most 100 g / 10 min, most preferably at most 80 g / 10 min.

  The polycarbonate fiber is not particularly limited, but can be obtained, for example, by melt-spinning the polycarbonate resin alone. Alternatively, the polycarbonate resin is mixed with various additives such as a thermoplastic resin and a flame retardant, a light stabilizer, an ultraviolet absorber, an antioxidant, and an antistatic agent, if necessary, and then melt-spun. be able to. Examples of other thermoplastic resins include, but are not particularly limited to, polyolefin resins such as polypropylene and polyethylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and aliphatic polyamide resins such as nylon 6 and nylon 66. No.

  The polycarbonate resin is not particularly limited. For example, “NOVAREX M7020A”, “NOVAREX M7020J” (NOVAREX is a registered trademark), and “UPILON H4000” (UPILON is a registered trademark) manufactured by Mitsubishi Engineering-Plastics Corporation. And other commercially available products.

  A fiber treating agent is attached to the surface of the polycarbonate fiber at a ratio of 0.05 to 3 parts by mass per 100 parts by mass of the polycarbonate fiber. The proportion of the fiber treating agent adhering to the surface of the polycarbonate fiber is determined by the productivity of the polycarbonate fiber, the processability in producing a sheet or a fiber-reinforced plastic for a fiber-reinforced plastic using the polycarbonate fiber, and the obtained fiber-reinforced plastic. In consideration of the mechanical properties of the material, it is preferably from 0.08 to 2 parts by mass, more preferably from 0.1 to 1 part by mass, and more preferably from 0.1 to 1 part by mass, per 100 parts by mass of the polycarbonate fiber. It is particularly preferable that the amount is from not less than 0.2 part by mass to not more than 0.8 part by mass, most preferably not less than 0.2 part by mass and not more than 0.6 part by mass.

  In the polycarbonate fiber, the fiber treating agent contains 70% by mass or more of one or more anionic surfactants selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl ether phosphates. Thereby, the processability such as the card passing property of the polycarbonate fiber and the dispersibility in the paper making process is improved, and the polycarbonate resin constituting the polycarbonate fiber is hardly deteriorated, and the fiber treating agent is easily dropped off by washing with water as needed. . In addition, the productivity when producing a sheet for fiber reinforced plastic is enhanced, and a fiber reinforced plastic obtained having high mechanical strength is easily obtained. Preferably, the fiber treating agent contains at least 80% by mass of one or more anionic surfactants selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl ether phosphates, and more preferably 90% by mass. The content is more preferably 95% by mass or more, particularly preferably 100% by mass.

  By attaching a fiber treating agent containing 70% by mass or more of one or more anionic surfactants selected from the group consisting of an alkyl phosphate ester salt and a polyoxyethylene alkyl ether phosphate to the polycarbonate fiber, When the sheet is manufactured by a dry method using a card machine, the cardability of the polycarbonate fiber in the card machine process is improved, and the generation of static electricity is suppressed. Further, when a sheet for fiber-reinforced plastic is manufactured by a wet method using a paper machine, the polycarbonate fiber and the reinforcing fiber are dispersed in water to obtain a papermaking slurry. It becomes easier to disperse.

  The polycarbonate fiber is a fiber containing 50% by mass or more of a polycarbonate resin. The polycarbonate resin is a thermoplastic resin having relatively low chemical resistance, and the polycarbonate resin may be adversely affected depending on the components of the fiber treating agent. The polycarbonate fiber of the present invention preferably uses a polycarbonate resin having an MFR of 40 g / 10 minutes or more in consideration of spinnability and fluidity when used as a matrix resin of fiber-reinforced plastic. It is considered that a large polycarbonate resin having a low viscosity at the time of melting has a small average molecular weight and a large proportion of polycarbonate molecules having a short molecular chain. Such a polycarbonate resin has a large average molecular weight and is more strongly affected by various chemicals such as a surfactant and an organic solvent as compared with a polycarbonate resin having a large proportion of polycarbonate molecules having a long molecular chain. It is presumed that the fiber treatment agent used for the polycarbonate fiber of the present invention is required to have an action of promoting deterioration of the polycarbonate resin as small as possible. By using a fiber treating agent containing 70% by mass or more of one or more anionic surfactants selected from the group consisting of the above-mentioned alkyl phosphate ester salts and polyoxyethylene alkyl ether phosphates, the fiber content of the polycarbonate resin is reduced. It is presumed that the treatment agent hardly affects the influence or the influence is small.

  The alkyl phosphate salt is preferably at least one anionic surfactant selected from the group consisting of the following general formulas (1) and (2).

In the general formula (1), R represents a hydrocarbon group having 8 to 24 carbon atoms, and may be any of a saturated hydrocarbon group, an unsaturated hydrocarbon group, and a hydrocarbon group having a branched chain. In the general formula (1), X ₁ and X ₂ are the same or different and represent a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation. However, at least one of X ₁ and X ₂ is not hydrogen. In the general formula (2), R ₁ and R ₂ each represent a hydrocarbon group having 8 to 24 carbon atoms, and may be any of a saturated hydrocarbon group, an unsaturated hydrocarbon group, and a hydrocarbon group having a branched chain. In the general formula (2), X ₃ represents a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation.

In the alkyl phosphate salt represented by the general formula (1) or (2), the hydrocarbon group (that is, the hydrocarbon group represented by R, R ₁ and R ₂ ) has 8 to 24 carbon atoms. Since the hydrophilicity and the hydrophobicity of the fiber treating agent can be balanced by being less than or equal to the above, the fixing property of the alkyl phosphate ester itself on the fiber surface is excellent, the dispersibility of the polycarbonate fiber in water, and when passing through the card. In each case, the effect of suppressing the generation of static electricity is good. Examples of the hydrocarbon group having 8 to 24 carbon atoms include octyl, nonyl, decyl, isodecyl, undecyl, dodecyl (lauryl), tridecyl, isotridecyl, tetradecyl (myristyl), pentadecyl Group, hexadecyl group, palmityl group, cetyl group, isopalmityl group, heptadecyl group, octadecyl group (stearyl group), isostearyl group, oleyl group, nonadecyl group, icosyl group, eicosyl group, henycosyl group, heneicosyl group, docosyl group (behenyl Group), a tetracosyl group, and the like, and also a mixed alkyl group thereof.

In the alkyl phosphate salt represented by the general formula (1) or (2), the hydrocarbon group represented by R, R ₁ and R ₂ preferably has 8 to 20 carbon atoms, more preferably 8 or more. 18 or less are more preferable, and 8 or more and 16 or less are especially preferable.

  The alkyl phosphate salt may include a monoalkyl phosphate salt represented by the general formula (1) and / or a dialkyl phosphate salt represented by the general formula (2). It is preferable to include the monoalkyl phosphate salt represented by (1).

  Preferably, the polyoxyethylene alkyl ether phosphate is at least one anionic surfactant selected from the group consisting of the following general formulas (3) and (4).

In the general formula (3), R ₃ represents a hydrocarbon group having 8 to 24 carbon atoms, and may be any of a saturated hydrocarbon group, an unsaturated hydrocarbon group, and a hydrocarbon group having a branched chain. In the general formula (1), X ₄ and X ₅ are the same or different and represent a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation. However, at least one of X ₄ and X ₅ is not hydrogen. k represents a number of 0.5 to 20, preferably 1 to 5 on a weight average. In the general formula (4), R ₄ and R ₅ represent a hydrocarbon group having 8 to 24 carbon atoms, and may be any of a saturated hydrocarbon group, an unsaturated hydrocarbon group, and a hydrocarbon group having a branched chain. In the general formula (4), X ₆ represents a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation, and m and n each represent a weight average of 0.5 to 20, Preferably a number of 1 to 5 is shown.

In the polyoxyethylene alkyl ether phosphate represented by the general formula (3) or (4), the number of carbon atoms of the hydrocarbon group represented by R ₃ in the general formula (3) and the general formula ( In 4), the number of carbon atoms of the hydrocarbon group represented by R ₄ and R ₅ is 8 or more and 24 or less, so that the hydrophilicity and the hydrophobicity of the fiber treating agent can be balanced. The ester salt itself is excellent in fixability to the fiber surface, and the dispersibility of the fiber containing the polycarbonate resin in water and the effect of suppressing the generation of static electricity when passing through the card are all good. Examples of the hydrocarbon group having 8 to 24 carbon atoms include octyl, nonyl, decyl, isodecyl, undecyl, dodecyl (lauryl), tridecyl, isotridecyl, tetradecyl (myristyl), pentadecyl Group, hexadecyl group, palmityl group, cetyl group, isopalmityl group, heptadecyl group, octadecyl group (stearyl group), isostearyl group, oleyl group, nonadecyl group, icosyl group, eicosyl group, henycosyl group, heneicosyl group, docosyl group (behenyl Group), a tetracosyl group, and the like, and also a mixed alkyl group thereof. In the polyoxyethylene alkyl ether phosphate represented by the general formula (3) or (4), the hydrocarbon group represented by R ₃ , R ₄ and R ₅ has 8 to 20 carbon atoms. It is preferably from 8 to 18 and more preferably from 8 to 16.

  In the polyoxyethylene alkyl ether phosphate represented by the general formula (3) or (4), ethylene oxide is addition-polymerized. The addition number of the addition-polymerized ethylene oxide is not particularly limited, but in the general formula (3) or the general formula (4), the addition number becomes 0.5 to 20 in weight average, preferably the general formula (3) or In the general formula (4), the number is added with an addition number of 1 to 5 on a weight average. When the number of added ethylene oxides satisfies the above range, the hydrophilicity and hydrophobicity of the fiber treating agent containing the polyoxyethylene alkyl ether phosphate can be balanced, so that the polyoxyethylene alkyl ether phosphate itself can be used. It is excellent in fixability to the fiber surface, and has excellent effects of dispersing the fiber containing the polycarbonate resin in water and suppressing the generation of static electricity when passing through the card.

  The alkyl phosphate salt represented by the general formula (1) or (2) and the polyoxyethylene alkyl ether phosphate represented by the general formula (3) or (4) are: , Partially neutralized product or completely neutralized product. Examples of the salt include an alkali metal salt, an alkaline earth metal salt, a zinc salt, a zirconium salt, an ammonium salt, an amine salt and the like, and an alkali metal salt such as a sodium salt and a potassium salt is preferable. Potassium salts are more preferred, and potassium salts are particularly preferred.

  The fiber treating agent may be used in combination of two or more kinds of alkyl phosphate esters or two or more kinds of polyoxyethylene alkyl ether phosphates. Examples of using two or more alkyl phosphate salts or polyoxyethylene alkyl ether phosphates in combination include those having different types of hydrocarbon groups, and those using potassium salts and sodium salts in combination. Can be In addition, if the fiber treating agent is a component that does not affect the polycarbonate resin, an alkyl phosphate ester salt and a polyoxyethylene alkyl are considered in consideration of the card passing property, antistatic property, and water dispersibility of the polycarbonate fiber. Surfactants other than ether phosphates may be included as active ingredients.

  The fiber treatment agent includes an anionic surfactant represented by the formulas (1) to (4), that is, an alkyl phosphate salt represented by the formula (1) or (2); The larger the content of the polyoxyethylene alkyl ether phosphate represented by the general formula (3) or (4), the better the antistatic property and hydrophilicity of the polycarbonate fiber to which the fiber treating agent is attached. In addition to this, it is considered that the influence on the polycarbonate resin constituting the polycarbonate fiber is reduced. The fiber treatment agent preferably contains 70% by mass or more, more preferably 75% by mass or more, and more preferably 80% by mass or more of the anionic surfactant represented by the general formulas (1) to (4). Is still more preferable, the content is more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. Since the active ingredient of the fiber treatment agent may be substantially only an alkyl phosphate ester salt or a polyoxyethylene alkyl ether phosphate, the active ingredient of the fiber treatment agent is represented by the general formulas (1) to (4). The upper limit of the content of the anionic surfactant to be used is 100% by mass. The fiber treatment agent is at least one anion selected from the group consisting of an alkyl phosphate salt represented by the general formula (1) and a polyoxyethylene alkyl ether phosphate represented by the general formula (3). It is preferable to contain 70% by mass or more of the surfactant, more preferably 75% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and 90% by mass or more. It is even more preferably contained, more preferably 95% by mass or more, particularly preferably 100% by mass.

  The fiber treating agent may contain components other than the anionic surfactants represented by the general formulas (1) to (4). The fiber treating agent may contain 30% by mass or less of other components, preferably 25% by mass or less, and more preferably 20% by mass or less. As the other component, surfactants used as conventional fiber treatment agents for synthetic fibers, for example, anionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used. , An anionic surfactant and / or an amphoteric surfactant. Examples of the anionic surfactant include a sulfate type (for example, alkyl sulfate), a sulfonate type (for example, paraffin (alkane) sulfonate), a carboxylic acid type (for example, fatty acid salt), and a phosphate type (for example, POE alkyl ( A) a phosphate or an alkyl phosphate) having 8 to 24 carbon atoms. Examples of the cationic surfactant include an ammonium type (for example, alkyltrimethylammonium chloride (having 8 to 24 carbon atoms)) and a benzalkonium type (for example, alkyldimethylbenzalkonium chloride (for having 8 to 24 carbon atoms)). Below)), and alkylamine type (eg, monomethylamine hydrochloride, dimethylamine hydrochloride, trimethylamine hydrochloride) and the like. Examples of the amphoteric surfactant include betaine-type (for example, dialkyl (C8 to C24) diaminoethylbetaine, alkyl (C8 to C24) dimethylbenzylbetaine) alkylamine oxide (for example, alkyl) Dimethylamine N oxide (having 8 to 24 carbon atoms), fatty acid amidopropyl betaine type, amino acid type (for example, alkyl (having 8 to 24 carbon atoms) glutamate), and glycine type (for example, dialkyl (for example, carbon number of 24)) Is 8 or more and 24 or less) diaminoethylglycine, alkyl (dimethylbenzylglycine having 8 or more and 24 or less carbon atoms) and the like.

  The fineness of the polycarbonate fiber is not particularly limited, but is preferably 0.5 dtex or more and 20 dtex or less, and more preferably 0.8 dtex or more and 10 dtex or less. When the fineness is 0.5 dtex or more, the spinning stability of the fiber is good. When the fineness is 20 dtex or less, a dense and uniform nonwoven fabric is easily obtained. The fiber length of the polycarbonate fiber is not particularly limited, but is, for example, preferably 2 mm or more and 150 mm or less, more preferably 3 mm or more and 100 mm or less, and more preferably 5 mm or more and 75 mm or less. Particularly preferred.

  In the case where the polycarbonate fiber is used for a sheet for a fiber-reinforced plastic, the fineness and the fiber length of the polycarbonate fiber may be appropriately selected according to a method for manufacturing a sheet for a fiber-reinforced plastic described later. For example, when the sheet for fiber reinforced plastic is a nonwoven fabric using a fiber web (dry method) produced by a card machine, the fineness of the polycarbonate fiber is preferably 0.8 dtex or more and 20 dtex or less, and 1.1 dtex or more. It is more preferably 15 dtex or less, particularly preferably 1.4 dtex or more and 10 dtex or less. At this time, the fiber length of the polycarbonate fiber is preferably 20 mm or more and 100 mm or less, more preferably 26 mm or more and 75 mm or less, and particularly preferably 30 mm or more and 65 mm or less. Further, when the fiber web constituting the sheet for fiber reinforced plastic is produced by the air lay method, the fineness of the polycarbonate fiber is preferably 0.8 dtex or more and 20 dtex or less, more preferably 1.1 dtex or more and 15 dtex or less. It is particularly preferred that the content be 1.4 dtex or more and 10 dtex or less. At this time, the fiber length of the polycarbonate fiber is preferably 2 mm or more and 100 mm or less, more preferably 5 mm or more and 90 mm or less, particularly preferably 5 mm or more and 85 mm or less, and 8 mm or more and 80 mm or less. Most preferred. When the fiber web constituting the sheet for fiber reinforced plastic is produced by a wet papermaking method (also referred to as a wet nonwoven fabric or simply a papermaking method), the fineness of the polycarbonate fiber for the fiber reinforced plastic is not less than 0.8 dtex and not more than 20 dtex. Is preferable, and it is more preferable that it is 1.1 dtex or more and 15 dtex or less, and it is especially preferable that it is 1.4 dtex or more and 10 dtex or less. At this time, the fiber length of the polycarbonate fiber for fiber reinforced plastic is preferably 2 mm or more and 20 mm or less, more preferably 2 mm or more and 15 mm or less, and particularly preferably 3 mm or more and 10 mm or less.

  The single fiber strength of the polycarbonate fiber is not particularly limited, but the single fiber strength is 0.85 cN / dtex or more in consideration of the productivity of the sheet for a fiber reinforced plastic described later and the handleability of the sheet for a fiber reinforced plastic. Is more preferable, and particularly preferably 0.9 cN / dtex or more. The upper limit of the single fiber strength of the polycarbonate fiber is not particularly limited, but is preferably 10 cN / dtex or less, and is preferably 7.5 cN / dtex or less from the viewpoint of availability and cost. More preferred. In the polycarbonate fiber, the single fiber elongation is not particularly limited, but is preferably 10% or more and 300% or less, more preferably 15% or more and 250% or less, and 20% or more and 200% or less. Is particularly preferred. In one embodiment of the present invention, the single fiber elongation of the polycarbonate fiber refers to the elongation measured according to JIS L 1015: 2010, and the single fiber strength of the polycarbonate fiber is measured according to JIS L 1015: 2010. Refers to tensile strength.

Although the polycarbonate fiber of the present invention is not particularly limited, for example, it can be produced by a production method including the following steps.
(1) A polycarbonate resin having a number average molecular weight (Mn) before spinning of 9000 or more and 16000 or less and a weight average molecular weight (Mw) of 22,000 or more and 36000 or less before spinning, or containing the polycarbonate resin in an amount of 50% by mass or more. Prepare the mixture.
(2) The polycarbonate resin or a mixture containing 50% by mass or more of the polycarbonate resin is melt spun at a temperature of 250 ° C. or more and 350 ° C. or less to obtain a spun filament.
(3) An alkyl phosphate ester salt and a polyoxyethylene alkyl ether phosphate in a proportion of 0.05 to 3 parts by mass per 100 parts by mass of the polycarbonate fiber with respect to the fiber surface of the spun filament (polycarbonate fiber). A fiber treatment agent containing 70% by mass or more of one or more anionic surfactants selected from the group consisting of:

  As the polycarbonate resin and the fiber treatment agent, those described above can be suitably used.

  The mixture may include other resins and additives as needed, as described above. From the viewpoint of improving the flame retardancy of the polycarbonate fiber, the above-described flame retardant can be suitably used as an additive. Preferably, a condensed phosphate ester is used as the flame retardant. The mixture contains the condensed phosphoric acid ester in an amount of 5% by mass or more and 30% by mass or less based on the total mass of the condensed phosphoric acid ester, the polycarbonate resin, and the mixture of the other resin and other additives mixed as necessary. Is preferred.

  The spinning draft at the time of the melt spinning may be, for example, 50 to 800 times or 100 to 700 times. The spinning draft can be determined by taking-up speed (m / min) / discharge linear speed (m / min). If the spinning draft is 50 times or more, tension is applied on the spinning line, and the yarn sway does not become noticeable, and a spun filament can be stably obtained. On the other hand, if the spinning draft is 800 times or less, the frequency of yarn breakage caused by excessively high tension on the spinning line is reduced, and a spun filament can be stably obtained.

  The application of the fiber treatment agent can be performed in the same manner as in the usual oil agent application step, and is not particularly limited. As a method of applying the fiber treatment agent to the spun filament, for example, a fiber of the polycarbonate fiber is immersed in a diluent obtained by diluting the fiber treatment agent with water, and dried if necessary. In addition to a method of attaching a fiber treatment agent to the surface, a method of attaching a fiber diluent diluted with water to a spun filament (polycarbonate fiber) by spraying the solution, and a method such as a roll touch method. At this time, the spun filament (polycarbonate fiber) may be an undrawn spun filament which has not been subjected to a stretching treatment after being subjected to melt spinning, or may be 1.1 times as large as the spun filament after the melt spinning. Stretching may be performed at a stretching ratio of not less than 1 and not more than 6 times. After the application of the fiber treating agent, crimping may be applied as necessary.

  Hereinafter, a sheet for a fiber-reinforced plastic containing the polycarbonate fiber will be described. The sheet for a fiber-reinforced plastic of the present invention contains the polycarbonate fiber and the reinforcing fiber. The sheet for fiber-reinforced plastics is such that, when the mass of the sheet for fiber-reinforced plastic is 100% by mass, the reinforcing fibers are 23.5% by mass or more and 80% by mass or less, and the polycarbonate fibers are 20% by mass or more and 76.5% by mass. % By mass or less. By setting the content of the reinforcing fiber and the polycarbonate fiber in the above-described range, the mechanical strength of the fiber-reinforced plastic using the fiber-reinforced plastic sheet increases. The fiber-reinforced plastic sheet contains 25% by mass to 75% by mass of the reinforcing fiber and 25% by mass to 75% by mass of the polycarbonate fiber when the mass of the sheet for the fiber-reinforced plastic is 100% by mass. More preferably, the reinforcing fiber content is 30% by mass or more and 70% by mass or less, and the polycarbonate fiber is more preferably 30% by mass or more and 70% by mass or less. It is particularly preferable that the fiber contains 35% by mass to 65% by mass of the fiber, and it is most preferable that the fiber contains 35% by mass to 45% by mass of the reinforcing fiber and 55% by mass to 65% by mass of the thermoplastic resin fiber.

  Examples of the reinforcing fiber include, but are not particularly limited to, aromatic polyamide fibers (also referred to as aramid fibers, and more specifically, polyparaphenylene terephthalamide fibers and polymetaphenylene terephthalamide fibers), and super. High-strength and low-elongation synthetic fibers such as high-molecular-weight polyethylene fibers, polyarylate fibers, and polyparaphenylenebenzoxazole fibers, carbon fibers, boron fibers, glass fibers, and ceramic fibers (specifically, silicon carbide fibers, alumina fibers, and silicon fibers) Various inorganic fibers and the like, such as Tyranno fibers (Tyranno and Tyranno fibers are registered trademarks) and the like made of (silicon) and a carbide of titanium or zirconia can be used. The reinforcing fibers can be selected according to the physical properties required for the obtained fiber-reinforced plastic. That is, when toughness and toughness against impact are required for fiber reinforced plastics, synthetic fibers having high strength and moderate elongation as reinforcing fibers, more preferably aromatic polyamide fibers, particularly preferably polyparaphenylene Preferably, it contains terephthalamide fibers. Further, if a fiber-reinforced plastic is used in applications where strength is important, as the reinforcing fiber, the fiber itself preferably contains higher-strength fiber, specifically, carbon fiber or various inorganic fibers as the reinforcing fiber. . Further, a plurality of types of the reinforcing fibers may be selected and used. Examples of using a plurality of types of reinforcing fibers selected include fiber-reinforced plastics containing carbon fibers and aromatic polyamide fibers as reinforcing fibers, and fiber-reinforced plastics containing glass fibers and aromatic polyamide fibers as reinforcing fibers.

  When an aromatic polyamide fiber is included as the reinforcing fiber, the single fiber elongation of the aromatic polyamide fiber is not particularly limited, but the single fiber elongation is preferably 2% or more. When the single fiber elongation of the aromatic polyamide fiber is 2% or more, the reinforcing fiber is easily deformed by deformation or impact. Therefore, when a fiber-reinforced plastic using this reinforcing fiber receives an impact, The fibers are stretched moderately so as to follow the plastic deformation, so that the impact is easily absorbed, and the impact resistance and fracture toughness are improved. The single fiber elongation of the reinforcing fiber is preferably 2.5% or more, and more preferably 3% or more, from the viewpoint of increasing mechanical strength such as fracture toughness and impact resistance of the obtained fiber-reinforced plastic. More preferably, it is 3.5% or more. The upper limit of the single fiber elongation of the aromatic polyamide fiber is not particularly limited, but is preferably 10% or less, more preferably 6% or less, from the viewpoint of the mechanical strength of the obtained fiber-reinforced plastic. preferable.

  When an aromatic polyamide fiber is used as the reinforcing fiber, the single fiber strength is preferably 16 cN / dtex or more, more preferably 18 cN / dtex, from the viewpoint of increasing the mechanical strength of the obtained fiber-reinforced plastic. It is particularly preferably at least 20 cN / dtex, most preferably at least 20.5 cN / dtex. The upper limit of the single fiber strength of the aromatic polyamide fiber is not particularly limited, but is preferably 40 cN / dtex or less, and more preferably 35 cN / dtex or less from the viewpoint of availability and cost. More preferred.

  When a carbon fiber is contained as the reinforcing fiber, the single fiber elongation of the carbon fiber is not particularly limited, but the single fiber elongation is preferably 0.2% or more and 3% or less, and 0.3% or less. It is more preferably at least 2.5% and particularly preferably at least 0.4% and no more than 2%. When the single fiber elongation of the carbon fiber satisfies the above range, in combination with the single fiber strength of the carbon fiber described below, the carbon fiber becomes a high-strength, low-elongation reinforcing fiber and is reinforced with this carbon fiber. The resulting fiber reinforced plastics have excellent mechanical strength and rigidity, and are suitable for various structural materials such as various types of vehicles and aircraft frames.

  When carbon fibers are used as the reinforcing fibers, the single fiber strength is preferably 6 cN / dtex or more, more preferably 8 cN / dtex or more, from the viewpoint of increasing the mechanical strength of the obtained fiber-reinforced plastic. It is particularly preferred that it is 10 cN / dtex or more. The upper limit of the single fiber strength of the carbon fiber is not particularly limited, but is preferably 45 cN / dtex or less, and more preferably 40 cN / dtex or less, from the viewpoint of availability and cost. , 35 cN / dtex or less, most preferably 30 cN / dtex or less. Carbon fibers are classified into PAN-based carbon fibers manufactured from acrylonitrile and pitch-based carbon fibers manufactured from pitch derived from petroleum, due to the difference in raw materials. If it is, it can be used without particular limitation. In addition to carbon fibers that are not used, carbon fibers are processed into fiber sheets or fiber reinforced plastics, etc., and then the fiber sheets or fiber reinforced plastics used as scraps, or the fiber reinforced plastics that have been used or discarded. Recycled carbon fiber obtained by collecting recycled fiber-reinforced plastics and removing organic matter other than carbon fiber by chemical treatment or heat treatment using chemicals (also called recycled carbon fiber or reused carbon fiber) Can also be used.

  In one embodiment of the present invention, the single fiber elongation of the reinforcing fiber refers to an elongation percentage measured according to JIS L 1015: 2010, and the single fiber strength of the reinforcing fiber is measured according to JIS L 1015: 2010. Refers to tensile strength.

  Although the fiber length of the reinforcing fiber is not particularly limited, the fiber length is preferably from 2 mm to 150 mm, more preferably from 3 mm to 100 mm, from the viewpoint of the mechanical strength of the obtained fiber-reinforced plastic. When the fiber length of the reinforcing fiber is less than 2 mm, the mechanical strength of the fiber reinforced plastic decreases. On the other hand, when the fiber length of the reinforcing fiber exceeds 150 mm, productivity at the time of manufacturing a sheet is inferior.

  The fineness of the reinforcing fibers is not particularly limited, but is preferably, for example, 0.5 dtex or more and 20 dtex or less, and more preferably 0.8 dtex or more and 10 dtex or less. When the fineness is 0.5 dtex or more, fibers are easily available. When the fineness is 20 dtex or less, a fiber aggregate including a nonwoven fabric can be easily formed, and a dense and uniform sheet for a fiber-reinforced plastic can be easily obtained.

  The sheet for fiber-reinforced plastic of the present invention is preferably in the form of a fibrous web or a nonwoven fabric, and more preferably a nonwoven fabric, from the viewpoint of productivity. The nonwoven fabric may be a wet nonwoven fabric or a dry nonwoven fabric. In the case of a wet nonwoven fabric, the fibrous web constituting the nonwoven fabric can be produced by a wet method (also called a wet papermaking method). In the case of a dry nonwoven fabric, the fibrous web constituting the nonwoven fabric may be produced using a machine such as a card machine, or may be produced by an air lay method.

The basis weight of the sheet for fiber-reinforced plastic is not particularly limited, but, for example, from the viewpoint of handleability, the basis weight is preferably 5 g / m ² or more, and more preferably 8 g / m ² or more. Further, from the viewpoint of moldability, the fiber reinforced plastic sheet preferably has a basis weight of 500 g / m ² or less, more preferably 400 g / m ² or less, and preferably 300 g / m ² or less. More preferred. The basis weight here is the basis weight per sheet for fiber reinforced plastic. The basis weight per sheet of the fiber reinforced plastic sheet is 5 g / m ² or more and 500 g / m ² or less. However, when the finally obtained fiber reinforced plastic is finished to be thick, A plurality of sheets in the range may be stacked, and a laminated sheet having a basis weight exceeding 500 g / m ² may be used as a fiber-reinforced plastic.

  In one embodiment of the present invention, the fiber-reinforced plastic contains the reinforcing fiber and a matrix resin, and when the volume of the fiber-reinforced plastic is 100% by volume, the ratio of the reinforcing fiber is 22% by volume or more and 75% by volume or less. Including. The fiber-reinforced plastic preferably contains the reinforcing fiber in a ratio of 25% by volume or more and 75% by volume or less, when the volume of the fiber-reinforced plastic is 100% by volume, and more preferably 30% by volume of the reinforcing fiber. % To 70% by volume, particularly preferably 35% to 65% by volume of the reinforcing fibers, and most preferably 35% to 45% by volume of the reinforcing fibers. .

  The matrix resin is obtained by melting the polycarbonate fibers and impregnating between the reinforcing fibers, and contains 50% by mass or more of the polycarbonate resin derived from the polycarbonate fibers. The polycarbonate resin contained in the matrix resin is measured using a fiber-reinforced plastic molded body as a sample in order to improve the mechanical properties of the fiber-reinforced plastic and to enhance the impregnation between the reinforcing fibers when producing the fiber-reinforced plastic. The number average molecular weight (Mn) is preferably 15,000 or less, more preferably 14,000 or less, still more preferably 13,000 or less, and particularly preferably 12,000 or less. In addition, the polycarbonate resin contained in the matrix resin preferably has a number average molecular weight (Mn) of 8,000 or more measured using the obtained fiber-reinforced plastic as a sample, from the viewpoint of easy availability and cost reduction. It is more preferably at least 9, more preferably at least 9,500, particularly preferably at least 10,000. In addition, the polycarbonate resin contained in the matrix resin is used to improve the mechanical properties of the fiber-reinforced plastic, and when manufacturing the fiber-reinforced plastic, in order to enhance the impregnation between the reinforcing fibers, the obtained fiber-reinforced plastic is used. The weight average molecular weight (Mw) measured as a sample is preferably 30,000 or less, more preferably 27,000 or less, still more preferably 26,000 or less, and particularly preferably 25,500 or less. In addition, the polycarbonate resin contained in the matrix resin preferably has a weight average molecular weight (Mw) of 20,000 or more measured using the obtained fiber-reinforced plastic as a sample, from the viewpoint of easy availability and cost reduction. More preferably, it is still more preferably 22500 or more, and particularly preferably 23000 or more.

  The matrix resin preferably contains the polycarbonate resin in an amount of 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more, from the viewpoint of further increasing mechanical strength such as impact resistance. It is even more preferred that the content be 90% by mass or more, and it is particularly preferable that the resin be substantially composed of a polycarbonate resin. Here, the term “substantially” is used in consideration of the fact that a resin provided as a product usually contains additives such as a stabilizer. In the matrix resin, the content of components other than the polycarbonate resin is preferably 30% by mass or less. Examples of the other components include other resin components and additives. Examples of the other resin component include olefin-based polymers such as polypropylene, polyethylene, polybutene, and polymethylpentene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; and homopolymers and copolymers such as polyamides such as nylon 6; , Polystyrene resin, acrylonitrile-styrene (AS) resin, acrylonitrile-butadiene-styrene (ABS) resin, and the like. As the polycarbonate resin, the same resin as that used for the sheet for fiber reinforced plastic may be used.

  The polycarbonate resin, which is a matrix resin of the fiber-reinforced plastic, has a melt flow rate (MFR; measured temperature of 300 ° C. and a load of 1) measured in accordance with ISO 1133 from the viewpoint that the impregnation of the polycarbonate resin between the reinforcing fibers is enhanced. .2 kgf) is preferably at least 40 g / 10 min, more preferably at least 45 g / 10 min, particularly preferably at least 50 g / 10 min, most preferably at least 52 g / 10 min. . The upper limit of the MFR of the polycarbonate resin is not particularly limited, but is preferably 140 g / 10 min or less, more preferably 125 g / 10 min or less, and more preferably 100 g / min, from the viewpoint of the mechanical properties of the fiber-reinforced plastic. It is particularly preferably 10 minutes or less, and most preferably 80 g / 10 minutes or less.

  In one embodiment of the present invention, the fiber reinforced plastic can be obtained by molding a laminate in which the sheets for fiber reinforced plastic are appropriately laminated. Specifically, by heating the laminate for fiber-reinforced plastic at a temperature equal to or higher than the melting point of the polycarbonate fiber, the thermal polycarbonate fiber is melted, and impregnated between the reinforcing fibers, thereby reducing the fiber-reinforced plastic. Obtainable. That is, the heat treatment causes the polycarbonate fibers to melt and become matrix resin. The molding method is not particularly limited as long as it can perform heat treatment. For example, press molding, stampable molding and the like can be used. By using a laminate of a fiber-reinforced plastic sheet containing reinforcing fibers and polycarbonate fibers, moldability is improved, and impregnation of the reinforcing fibers with the matrix resin is improved.

  The fiber reinforced plastic preferably has a bending strength of 200 MPa or more, and is preferably 250 MPa or more, measured according to Method A (bending test method by three-point bending) of JIS K 7074: 1998 (bending test method of carbon fiber reinforced plastic). It is more preferably at least 280 MPa. When the bending strength is in the above-mentioned range, the fiber-reinforced fiber-reinforced plastic has sufficient strength for bending, so that it is suitably used as a structural material for various structural materials, specifically, various types of vehicles such as automobiles and aircraft. Can be used. Such a fiber-reinforced plastic is obtained by using the polycarbonate fiber of the present invention as a matrix resin, and as a reinforcing fiber, a high-strength, low-elongation reinforcing fiber, specifically, a carbon fiber, a boron fiber, a glass fiber or a ceramic fiber (a silicon carbide fiber). Fiber-reinforced plastics using various inorganic fibers such as, for example, alumina fibers, Tyranno fibers made of fibers of silicon and titanium or zirconia carbide (Tyranno and Tyranno fibers are registered trademarks) and the like can be easily prepared. Obtainable. The upper limit of the bending strength of the fiber reinforced plastic is not particularly limited, but may be 750 MPa or less, 650 MPa or less, or 600 MPa or less.

  The fiber-reinforced plastic preferably has a flexural modulus of 8 GPa or more measured according to the method A (bending test method by three-point bending) of JIS K 7074: 1998 (bending test method of carbon fiber-reinforced plastic), It is more preferably at least 10 GPa, particularly preferably at least 15 GPa. When the flexural modulus is in the above range, the fiber-reinforced fiber-reinforced plastic has sufficient rigidity against bending, so that it is suitably used as a structural material for various types of structural materials, specifically, various types of vehicles such as automobiles and aircraft. Can be used. Such a fiber-reinforced plastic is obtained by using the polycarbonate fiber of the present invention as a matrix resin, and as a reinforcing fiber, a high-strength, low-elongation reinforcing fiber, specifically, a carbon fiber, a boron fiber, a glass fiber or a ceramic fiber (a silicon carbide fiber). Fiber-reinforced plastics using various inorganic fibers, such as alumina fibers, Tyranno fibers made of silicon (silicon) and carbide of titanium or zirconia (Tyranno and Tyranno fibers are registered trademarks) and the like. Can be obtained at The upper limit of the fiber-reinforced plastic flexural modulus is not particularly limited, but may be 50 GPa or less, 40 GPa or less, or 35 GPa or less.

The fiber-reinforced plastic, Charpy impact strength, measured in accordance with JIS K 7111 is at 45 kJ / m ² or more, preferably 50 kJ / m ² or more, more preferably 55 kJ / m ² or more. When the Charpy impact strength is in the above-mentioned range, the impact resistance is good, and the Charpy impact strength can be suitably used as a fiber-reinforced plastic used for various transport containers such as a carry case, or a case of a precision machine or an electronic device. Such a fiber-reinforced plastic is obtained by using the polycarbonate fiber of the present invention as a matrix resin, and as a reinforcing fiber, a reinforcing fiber having a relatively large single-fiber elongation, specifically, various aromatic polyamide fibers, polyparaphenylene benzoxazole fibers, and ultra-fine fibers. It can be obtained by forming a fiber-reinforced plastic using synthetic fibers such as high molecular weight polyethylene fibers and polyarylate fibers.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.

  Hereinafter, various measurement methods will be described.

(Melt flow rate of polycarbonate resin)
The melt flow rate (MFR) of the polycarbonate resin was measured under the conditions of a temperature of 300 ° C. and a load of 1.2 kgf according to ISO 1133.

(Measurement of molecular weight distribution of polycarbonate resin)
The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the polycarbonate resin (before spinning) or the polycarbonate resin contained in the polycarbonate fiber or the fiber-reinforced plastic are calculated by gel permeation chromatography (GPC) in terms of polystyrene equivalent molecular weight distribution. did. For the measurement, a gel permeation chromatograph equipped with a differential refractive index (RI) detector as a detector (“HLC-8220GPC” manufactured by Tosoh Corporation) was used.

Specifically, a sample (pellet, fiber, or fiber-reinforced plastic) containing a polycarbonate resin is weighed and added to tetrahydrofuran (THF) so that the polycarbonate resin is 0.1 wt / vol%, and gently stirred. Dissolved. Next, in order to remove an undissolved sample (for example, a reinforcing fiber when the sample is a fiber-reinforced plastic) from the solution in which the sample was dissolved, this solution was filtered with a filter to obtain a sample solution for measurement. . The obtained sample solution for measurement is injected into the gel permeation chromatograph under the conditions of a flow rate of 1.0 mL / min and an injection volume of 100 μL, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured. did.
When measuring, Shodex (registered trademark) KF-G (1), KF-805L (2), and KF-800D (1) manufactured by Showa Denko KK were used as columns, and the temperature of the column thermostat was adjusted. It was measured at 40 ° C.

(Single fiber strength and tensile elongation)
According to JIS L 1015: 2010, the load value and elongation at the time of fiber cutting were measured using a tensile tester, and the measured values were defined as single fiber strength and tensile elongation, respectively.

(Fineness and fiber length)
It was measured according to JIS L 1015: 2010.

(Amount of fiber treatment agent)
The amount of the fiber treating agent attached to the fiber surface was measured by a rapid extraction method using an R-II type quick residual oil extraction device manufactured by Tokai Keiki Co., Ltd. First, about 4 g of a fiber for measuring the amount of the fiber treating agent to be adhered was collected and processed into a fiber web by a card machine, and the mass (W _f (g)) of the obtained fiber web was measured. After the fibrous web whose mass was measured was filled in a metal cylinder (inner diameter 16 mm, length 130 mm, bottom having a mortar shape and a hole having a diameter of 1 mm at the bottom), 10 mL of methanol was charged from above. The fiber treating agent attached to the surface of the fiber is dissolved in the charged methanol and is dropped from the bottom hole of the metal cylinder, so that the methanol dropped from the bottom hole is transferred to an aluminum plate. Receiving while heating, methanol was evaporated. At this time, the aluminum dish for collecting the methanol that is dripped is washed thoroughly and then dried sufficiently using a dryer, but before receiving the methanol, the mass (the mass of the aluminum dish only: W ₁ (g)) was measured. By transferring all the methanol in the metal cylinder to the aluminum dish and completely evaporating the methanol, the fiber treatment agent extracted from the fibers remains in the aluminum dish. The mass (W ₂ (g)) of the aluminum dish in which the fiber treating agent remained was measured, and the amount of the fiber treating agent attached to the fiber surface was calculated from the following equation 1.
[Where,
W ₁ indicates the mass of the aluminum dish,
W ₂ represents the total mass of the aluminum dish and the fiber treatment agent,
W _f represents the mass of fibers used as a sample. ]

(Fiber volume content)
A 100 mg sample of the fiber reinforced plastic for measuring the fiber volume content is weighed. 100 mL of dichloromethane was added to the weighed sample, and the mixture was gently stirred at room temperature (25 ° C.) for 2 weeks, filtered with a 45 μm filter, and the residue was washed with sufficient dichloromethane and dried. Next, the residue is released by pressurization, added again to 100 mL of dichloromethane, gently stirred at room temperature (25 ° C.) for 1 week, filtered through a 45 μm filter, and the residue is washed with sufficient dichloromethane and dried to obtain a matrix. The resin was completely removed, and the mass of the reinforcing fiber was measured. The mass content of the fiber-reinforced plastic sample was taken as 100%, the mass content of the reinforcing fiber was obtained, and then the volume was converted from the respective densities to calculate the fiber volume content.

(Bending strength of fiber reinforced plastic)
A sample having a width of 15 mm, a length of 100 mm, and a thickness of 2 mm from the obtained fiber reinforced plastic in accordance with JIS K 7074: Method A (bending test method by three-point bending) of 1998 (bending test method of carbon fiber reinforced plastic). Was prepared, and the bending strength was measured at a test speed of 5 mm / min using an autograph (registered trademark) AG-100 kN IS manufactured by Shimadzu Corporation at a distance between fulcrums of 80 mm.

(Flexural modulus of fiber reinforced plastic)
A sample having a width of 15 mm, a length of 100 mm, and a thickness of 2 mm from the obtained fiber reinforced plastic in accordance with JIS K 7074: Method A (bending test method by three-point bending) of 1998 (bending test method of carbon fiber reinforced plastic). Using an Autograph (registered trademark) AG-100 kN IS manufactured by Shimadzu Corporation, the flexural modulus was measured at a test speed of 5 mm / min with a distance between fulcrums of 80 mm.

(Charpy impact strength of fiber reinforced plastic)
In accordance with JIS K 7111: 2012, a test piece (edgewise, No. 1 test piece, C notch) having a thickness of 2 mm, a length of 80 mm, and a width of 10 mm was used and measured at a weighing capacity of 5 J. Specifically, the test piece was set on a beam at an interval of 60 mm, the hammer was shaken down from the upper part, and the test piece set on the lower beam was broken. Charpy impact strength was calculated from the absorbed energy at the time of breaking.

The following fibers were used as the reinforcing fibers. Table 1 shows the physical properties of the reinforcing fibers.
(1) Reinforcing fiber 1: para-aromatic polyamide fiber, "Technola (registered trademark)" manufactured by Teijin Limited, fineness 1.7 dtex, fiber length 51 mm, density 1.39 g / cm ³
(2) Reinforcing fiber 2: Para-based aromatic polyamide fiber, "Technola (registered trademark)" manufactured by Teijin Limited, fineness 1.7 dtex, fiber length 6 mm, density 1.39 g / cm ³
(3) Reinforcing fiber 3: para-aromatic polyamide fiber, "Twaron (registered trademark)" manufactured by Teijin Limited, fineness 1.7 dtex, fiber length 50 mm, density 1.44 g / cm ³
(4) Reinforcing fiber 4: para-aromatic polyamide fiber, "Twaron (registered trademark)" manufactured by Teijin Limited, fineness 1.7 dtex, fiber length 1 mm, density 1.44 g / cm ³
(5) Reinforcing fiber 5: carbon fiber, “HTC140X” manufactured by Toho Tenax Co., Ltd., fineness 0.7 dtex, fiber length 50 mm, density 1.8 g / cm ³
(6) Reinforcing fiber 6: Recycled carbon fiber that is commercially available. Fineness 0.38 dtex, fiber length 30-60 mm, density 1.8 g / cm ³

(Example 1)
A polycarbonate resin (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name “NOVAREX (registered trademark) 7020J”, hereinafter also simply referred to as “PC resin 1”) was prepared. The MFR of the polycarbonate resin was 63 g / 10 min, the number average molecular weight (Mn) before spinning was 13000, the weight average molecular weight (Mw) before spinning was 28500, and the density was 1.2 g / cm ³ . there were. The polycarbonate resin was melt-extruded using a spinning nozzle (pore diameter: 0.6 mm) at a spinning temperature of 300 ° C., and a draw ratio (spinning draft) was 360 times to obtain a spun filament having a fineness of 7.8 dtex.

  To the obtained spun filament, 35% by mass of potassium dodecyl phosphate (potassium lauryl phosphate) as an active ingredient and potassium polyoxyethylene alkyl ether phosphate containing octyl group as a hydrocarbon group (POE octyl ether) A fiber treating agent containing 65% by mass of potassium phosphate (hereinafter referred to as a fiber treating agent 1) is prepared, and diluted with water so that the concentration of the fiber treating agent 1 becomes 3% by mass. The spun filament is immersed in the diluted solution, the spun filament impregnated with the diluted solution of the fiber treating agent 1 is introduced into crimper rolls, crimping is performed with the crimper roll, and excess dilute solution is squeezed out. Dropped. Then, after a drying process at 100 ° C. for 15 minutes, the water on the fiber surface was evaporated and dried, and then cut into a fiber length of 51 mm with a cutter to obtain the fiber of Example 1. Using the dried fiber of Example 1, the adhesion amount of the fiber treating agent to the fiber of Example 1 was measured by the method described above, and the fiber treating agent was 0.35 parts by mass with respect to 100 parts by mass of the polycarbonate fiber. Had adhered.

(Example 2)
After impregnating the diluted solution of the fiber treating agent 1 with the spun filament, without using crimper rolls, squeezing out the excess diluted solution by sandwiching between two rolls whose surfaces are covered with rubber, The fiber of Example 2 was obtained by cutting without drying, that is, cutting the fiber length to 5 mm with the spun filament wet.

(Example 3)
Example 2 Example 2 was repeated except that a polycarbonate resin sold by Mitsubishi Engineering-Plastics Corporation (trade name “Iupilon (registered trademark) H4000” or less, also simply referred to as “PC resin 2”) was used as a raw material polycarbonate resin. In the same manner as described above, the fiber of Example 3 (fiber length 5 mm) was obtained. The polycarbonate resin ("Iupilon (registered trademark) H4000") had a number average molecular weight (Mn) before spinning of 12,600, a weight average molecular weight (Mw) before spinning of 29,200, and a ratio of the weight average molecular weight to the number average molecular weight. (Mw / Mn) is 2.3. The obtained polycarbonate fiber was measured as a sample. The number average molecular weight (Mn) after spinning was 12100, the weight average molecular weight (Mw) after spinning was 28500, and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn). ) Is 2.4.

(Examples 4 to 6, Comparative Examples 1 and 2)
In addition to the fiber treating agent 1, a fiber treating agent shown in Table 2 below was prepared. Using these fiber treating agents in place of the fiber treating agent 1, a diluted solution of the fiber treating agent having an active ingredient concentration of 3% was prepared. As shown in Table 3, a fiber (fiber length: 5 mm) was produced in the same manner as in Example 3, except that a diluted solution of the fiber treating agents 2 to 6 was used instead of the diluted solution of the fiber treating agent 1.

(Example 7)
A polycarbonate resin (trade name "Iupilon (registered trademark) H4000") sold by Mitsubishi Engineering-Plastics Corporation is prepared as a polycarbonate resin as a raw material. The polycarbonate resin and the condensed phosphate ester were mixed so that the blended amount of the condensed phosphate ester flame retardant was 12% by mass. The condensed phosphate ester flame retardant has a chemical formula represented by [(CH ₃ ) ₂ C ₆ H ₃ O] ₂ P (O) OC ₆ H ₄ OP (O) [OC ₆ H ₃ (CH ₃ ) ₂ ] ₂ (Trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.). The melt spinning was performed using the mixture of the polycarbonate resin and the condensed phosphate ester-based flame retardant, and the melt spinning was performed in the same manner as in Example 4 except that the fineness of the spun filament was set to 8.8 dtex. 7 were obtained.

(Comparative Example 3)
Spinning using a nylon resin (“UBE Nylon (registered trademark) SF1018A” manufactured by Ube Industries, Ltd.), number average molecular weight 18000, density before spinning 1.14 g / cm ³ , hereinafter also simply referred to as “PA resin”. A fiber of Comparative Example 3 having a fiber length of 6 mm was obtained in the same manner as in Example 2 except that the temperature was 280 ° C.

(Reference Example 1)
In Example 3, the spun filament before impregnation with the fiber treating agent was cut so that the fiber length became 5 mm, to obtain a fiber of Reference Example 1.

  Regarding the obtained fibers of Examples 1 to 7, Comparative Examples 1 to 3, and Reference Example 1, the fineness, fiber length, single fiber strength and tensile elongation were measured as described above, and the results are shown in the following table. 3 and Table 4.

  As can be seen from the results in Tables 3 and 4, a fiber treatment agent containing at least 70% by mass of one or more anionic surfactants selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl ether phosphates. The polycarbonate fibers of Examples 1 to 7 to which the carbon fiber was attached had a high single fiber strength, which was almost equal to the single fiber strength of the polycarbonate fiber of Reference Example 1 to which no fiber treatment agent was attached, and all were 1.0 cN. / Dtex. On the other hand, Comparative Examples 1 and 2 to which fiber treatment agents containing less than 70% by mass of one or more anionic surfactants selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl ether phosphates are attached. And the single fiber strength was 0.83 cN / dtex or less, which was low.

(Example 8)
<Preparation of sheet for fiber reinforced plastic>
The polycarbonate fiber and the reinforcing fiber 1 of Example 1 obtained above were mixed so as to have the contents shown in Table 5 below, and a card web having a basis weight of 100 g / m ² was obtained using a parallel card machine. . The obtained fiber web was subjected to a needle punching treatment to entangle the fibers. Needle punching is performed by using a needle of number 40 (number of barbs: 9), setting the needle depth to 10 mm, and performing a needle punching process under the condition that the number of penetrations is 120 needles / cm ² . I got a sheet.

<Preparation of laminate for fiber reinforced plastic>
The fiber-reinforced plastic sheet (non-woven fabric) obtained above is laminated with 24 sheets so that the longitudinal direction in the non-woven fabric production direction and the direction perpendicular to the longitudinal direction in the non-woven fabric production direction are alternately arranged. A laminate for reinforced plastic was obtained.

<Preparation of fiber reinforced plastic>
The fiber-reinforced plastic laminate obtained above is set in a stainless steel concave-shaped lower mold that has been subjected to a mold release treatment, and the stainless steel convex mold that has also been subjected to a mold release treatment is lowered. The pressure was maintained at 5 MPa and the temperature at 280 ° C. for 3 minutes to melt the polycarbonate fibers serving as the matrix resin. Next, cooling water is passed through the mold to start cooling the mold, and at the same time, the mold is pressurized at a pressure of 15 MPa, and a molded product is taken out when the mold temperature has dropped to 100 ° C., whereby a fiber-reinforced plastic having a thickness of about 2 mm is removed. Produced.

(Example 9)
<Preparation of sheet for fiber reinforced plastic>
The polycarbonate fiber and the reinforcing fiber 2 of Example 2 obtained above were mixed so as to have the contents shown in Table 5 below, and a fiber web having a basis weight of 200 g / m ² was obtained by a wet papermaking method. The fiber web was subjected to a heat and pressure treatment for 1 minute using a Yankee dryer (pressure 2 MPa) set at 145 ° C. to obtain a heat-bonded nonwoven fabric.

<Preparation of laminate for fiber reinforced plastic>
Twelve nonwoven fabrics (sheets for fiber-reinforced plastic) obtained by the above wet papermaking method are arranged such that the longitudinal direction in the nonwoven fabric production direction and the direction perpendicular to the longitudinal direction in the nonwoven fabric production direction alternate. Lamination was performed to obtain a laminate for fiber reinforced plastic.

<Preparation of fiber reinforced plastic>
Using the laminate for fiber-reinforced plastic obtained above, a fiber-reinforced plastic having a thickness of about 2 mm was produced in the same procedure as in Example 8.

(Example 10)
A sheet for fiber-reinforced plastic, a laminate for fiber-reinforced plastic, and a fiber-reinforced plastic were prepared in the same manner as in Example 9 except that the contents of the polycarbonate fiber and the reinforcing fiber 2 in Example 2 were as shown in Table 1. Produced.

(Example 11)
A sheet for a fiber-reinforced plastic, a laminate for a fiber-reinforced plastic, and a fiber-reinforced plastic were prepared in the same manner as in Example 9 except that the pressure during cooling was set to 20 MPa.

(Example 12)
A sheet for a fiber-reinforced plastic, a laminate for a fiber-reinforced plastic, and a fiber-reinforced plastic were produced in the same manner as in Example 8, except that the reinforcing fiber 3 was used instead of the reinforcing fiber 1.

(Example 13)
A sheet for fiber-reinforced plastic, a laminate for fiber-reinforced plastic, and a fiber-reinforced plastic were produced in the same manner as in Example 9, except that the polycarbonate fiber of Example 3 was used instead of the polycarbonate fiber of Example 2.

(Example 14)
A sheet for a fiber-reinforced plastic, a laminate for a fiber-reinforced plastic, and a fiber-reinforced plastic were produced in the same manner as in Example 8, except that the reinforcing fiber 5 was used instead of the reinforcing fiber 1.

(Example 15)
The polycarbonate fiber of Example 7 and the reinforcing fiber 6 obtained above were mixed so as to have the contents shown in Table 5 below, and a card web having a basis weight of 300 g / m ² was obtained using a parallel card machine. . The obtained fiber web was subjected to a needle punching treatment to entangle the fibers to obtain a sheet for fiber reinforced plastic.

  The fiber-reinforced plastic sheet (nonwoven fabric) obtained above is laminated six times so that the longitudinal direction in the nonwoven fabric production direction and the direction perpendicular to the longitudinal direction in the nonwoven fabric production direction alternate with each other. A laminate for reinforced plastic was obtained.

<Production of flame-retardant fiber reinforced plastic>
The fiber-reinforced plastic laminate obtained above is set in a stainless steel concave-shaped lower mold that has been subjected to a mold release treatment, and the stainless steel convex mold that has also been subjected to a mold release treatment is lowered. The pressure was kept at 20 MPa and the temperature at 270 ° C. for 3 minutes to melt the polycarbonate fibers serving as the matrix resin. Next, cooling water is passed through the mold to start cooling the mold. At the same time, the pressure is increased to 15 MPa, and the molded product is taken out at the stage when the mold temperature has dropped to 100 ° C., whereby a fiber-reinforced plastic having a thickness of about 2 mm is removed. Produced.

(Comparative Example 4)
A fiber sheet, a laminate and a molded article were produced in the same manner as in Example 9 except that only the polycarbonate fiber of Example 1 was used without using the reinforcing fiber.

(Comparative Example 5)
A sheet for fiber-reinforced plastic, a laminate for fiber-reinforced plastic, and a fiber-reinforced plastic were produced in the same manner as in Example 9, except that the fiber of Comparative Example 3 was used instead of the polycarbonate fiber of Example 2.

(Comparative Example 6)
A sheet for fiber-reinforced plastic, a laminate for fiber-reinforced plastic, and a fiber-reinforced plastic were produced in the same manner as in Example 9 except that the fiber of Comparative Example 1 was used instead of the polycarbonate fiber of Example 2.

  Various physical properties of the sheets for fiber-reinforced plastics of Examples 8 to 15 and Comparative Examples 4 to 6, and the volume content (Vf) of the reinforcing fibers, the bending strength, and the flexural modulus measured by using the obtained fiber-reinforced plastics. Tables 5 and 6 below show the measurement results of the Charpy impact strength and the like.

<Evaluation of flame retardancy>
A combustion test was performed on the fiber-reinforced plastic of Example 15 by the following method to confirm its flame retardancy.
The fiber reinforced plastic (thickness: 2 mm) obtained in Example 15 was cut so that the length and width were 125 mm x 13 mm, and the fiber reinforced plastic piece was held so that the vertical direction was vertical. At this time, absorbent cotton was spread and placed at a position 30 cm in the vertical direction from the tip of the fiber reinforced plastic piece hanging in the vertical direction, and if there was a drip of the resin melted during the combustion test, it was ignited. Then, the flame of the gas burner was brought into contact with the tip of the fiber-reinforced plastic piece (that is, the tip opposite to the held tip) for 10 seconds, and it was confirmed how the fiber-reinforced plastic piece burned.

  Although the fiber-reinforced plastic piece of Example 15 was in a red-hot state due to contact with the flame of the gas burner, the red-hot state disappeared immediately after the predetermined time had elapsed and the flame of the gas burner was moved away from the sample, and smoke was also emitted. Did not occur. Further, since no molten resin was generated when the flame of the gas burner was in contact or after the flame of the gas burner was kept away, ignition to the absorbent cotton did not occur. From these results, the fiber reinforced plastic of Example 15 has sufficient mechanical strength and high flame retardancy by using a polycarbonate resin containing 12% by mass of a flame retardant as a matrix resin. Was confirmed.

The fiber reinforced plastics of Examples 8 to 13 using the polycarbonate fiber of the example and the sheet for the fiber reinforced plastic having the tensile elongation of 2% or more and the fiber length of 2 mm to 150 mm, The impact strength was 45 kJ / m ² or more, and the mechanical strength was excellent. In Examples 9 and 11, the content of the reinforcing fiber in the sheet for fiber-reinforced plastic was the same, but the volume content of the reinforcing fiber in the fiber-reinforced plastic was different in Example 11 when cooled. Is high, and more molten thermoplastic resin fibers (matrix resin) flow out of the system.

On the other hand, the molded article obtained in Comparative Example 4 using a fiber sheet containing no reinforcing fiber had a Charpy impact strength of less than 10 kJ / m ² and was inferior in mechanical strength.

Comparing the molded body of Example 9 with the molded body of Comparative Example 6, the types and proportions of the reinforcing fibers used, the heating temperature when forming the molded body, the pressure during melting of the resin, and the like are the same, The Charpy strength of the molded article of Example 9 is 69.5 kJ / m ² , whereas the Charpy strength of the molded article of Comparative Example 6 is about half, 34.5 kJ / m ² . Comparing the polycarbonate fiber used in the molded article of Example 9 with the polycarbonate fiber used in Comparative Example 6, the polycarbonate fiber used in the molded article of Example 9 (Example 2) adheres to the fiber surface. While the fiber treating agent contains at least 70% by mass of one or more anionic surfactants selected from the group consisting of alkyl phosphate ester salts and polyoxyethylene alkyl ether phosphate salts, the molding of Comparative Example 6 The polycarbonate fiber used in the body (Comparative Example 1) is one in which the fiber treatment agent attached to the fiber surface is at least one anionic system selected from the group consisting of alkyl phosphate ester salts and polyoxyethylene alkyl ether phosphate salts. Polycarbonate that does not contain surfactant and forms polycarbonate fiber depending on the fiber treatment agent Different degree of bets resin degradation is believed that differences in Charpy strength of the obtained molded body is out.

  As a matter of fact, as shown in Tables 3 and 4 above, when the polycarbonate fiber of Example 2 is compared with the polycarbonate fiber of Comparative Example 1, the fiber of Example 2 has a single fiber strength of 1.23 cN / In contrast to the dtex, the fiber of Comparative Example 1 had a single fiber strength of 0.83 cN / dtex.

  Comparing the fiber reinforced plastic of Example 13 with the fiber reinforced plastic of Example 14, a fiber having a higher single fiber strength, specifically, a fiber reinforced plastic reinforced using a high-strength carbon fiber (Example 14) ) Had higher flexural strength and flexural modulus than fiber-reinforced plastic (Example 13) reinforced using aramid fibers having a lower single fiber strength than carbon fibers. From these results, it can be seen that the use of high-strength, low-elongation fibers results in a fiber-reinforced plastic having higher rigidity and higher mechanical strength. On the other hand, a fiber reinforced plastic reinforced using a fiber having a higher single fiber elongation, specifically, an aramid fiber having a high strength and a single fiber elongation of 2% or more (Example 13) has a low elongation. Has a higher Charpy impact strength than a fiber-reinforced plastic using carbon fibers. From these results, it is found that the use of high-strength fibers that have relatively high elongation (specifically, single-fiber elongation of 2% or more) makes the resulting fiber-reinforced plastic sticky to impact (resistance to impact). It can be seen that the impact strength is large and the fracture toughness is large.

  The polycarbonate fiber of the present invention is finished by using a fiber treating agent containing a specific component, thereby spinning, drawing, and, if necessary, cutting a predetermined fiber length to obtain a finished polycarbonate fiber. Even if stored for a certain period of time, deterioration of the polycarbonate resin having relatively low chemical resistance hardly progresses, and the strength of a single fiber at the time of production can be maintained. Therefore, in the case of a dry non-woven fabric made of a polycarbonate fiber-based fiber sheet, particularly a fiber sheet formed by a card method, the card passability is good, and the productivity of the dry non-woven fabric is improved. Since the deterioration of the polycarbonate resin has not progressed or the deterioration is slight, the polycarbonate fiber of the present invention can be used for various fiber products, for example, filter media for various filters (for example, ventilation fan filters, air conditioners, air purifiers, etc.). Filter media that allow gas to pass therethrough, and filter media that allows liquids such as water to pass therethrough) and insulating fiber sheets.

  The polycarbonate fiber of the present invention has good fluidity of the polycarbonate resin contained in the fiber, and the deterioration of the polycarbonate resin caused by the fiber treatment agent during the storage period is difficult to progress, or the deterioration is slight, It is preferable to obtain a fiber sheet in which the polycarbonate fiber of the present invention and various reinforcing fibers are blended, and a fiber-reinforced plastic molded article obtained by heat-molding the fiber sheet. The polycarbonate fiber of the present invention has high impact resistance when used as a fiber-reinforced plastic because the deterioration of the polycarbonate resin has not progressed.

  In addition, the polycarbonate fiber of the present invention can impart high flame retardancy while maintaining the mechanical properties of the polycarbonate resin, preferably by using a condensed phosphate ester as a flame retardant. Such a polycarbonate fiber and a fiber-reinforced plastic obtained using the same are used for various members using the fiber-reinforced plastic, in particular, structural parts of various vehicles and aircraft, which require high mechanical properties and high flame retardancy. It is preferably used for applications such as structural parts, various electric devices requiring light weight and small size, housings and reinforcing materials for various electronic devices.

Claims (17)

A polycarbonate fiber containing at least 50% by mass of a polycarbonate resin,
On the surface of the polycarbonate fiber, a fiber treatment agent is attached at a ratio of 0.05 part by mass or more and 3 parts by mass or less per 100 parts by mass of the polycarbonate fiber,
A polycarbonate fiber, wherein the fiber treating agent contains at least 70% by mass of one or more anionic surfactants selected from the group consisting of an alkyl phosphate ester salt and a polyoxyethylene alkyl ether phosphate. The polycarbonate fiber according to claim 1, wherein the alkyl phosphate salt is at least one anionic surfactant selected from the group consisting of the following general formulas (1) and (2).
In the general formula (1), R represents a hydrocarbon group having 8 to 24 carbon atoms, and X ₁ and X ₂ are the same or different and are a hydrogen atom or an atom that can be a monovalent cation, or a monovalent cation. Indicates an atomic group that can be: However, at least one of X ₁ and X ₂ is not hydrogen. In the general formula (2), R ₁ and R ₂ each represent a hydrocarbon group having 8 to 24 carbon atoms, and X ₃ represents a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation. Is shown. The polycarbonate fiber according to claim 1 or 2, wherein the polyoxyethylene alkyl ether phosphate is at least an anionic surfactant selected from the group consisting of the following general formulas (3) and (4).
In the general formula (3), R ₃ represents a hydrocarbon group having 8 to 24 carbon atoms, and X ₄ and X ₅ are the same or different and are a hydrogen atom or an atom which can be a monovalent cation, or a monovalent cation. Indicates an atomic group that can be a cation. However, at least one of X ₄ and X ₅ is not hydrogen. k shows the number of 0.5-20 on a weight average. In the general formula (4), R ₄ and R ₅ each represent a hydrocarbon group having 8 to 24 carbon atoms, and X ₆ represents a hydrogen atom, an atom that can be a monovalent cation, or an atomic group that can be a monovalent cation. And m and n each represent a number of 0.5 to 20 in weight average.   The fiber treating agent is at least one anionic interface selected from the group consisting of an alkyl phosphate salt represented by the general formula (1) and a polyoxyethylene alkyl ether phosphate represented by the general formula (3). The polycarbonate fiber according to any one of claims 1 to 3, comprising at least 70% by mass of an activator.   The polycarbonate fiber according to any one of claims 1 to 4, wherein the polycarbonate resin has a number average molecular weight of 9,000 or more and 16,000 or less and a weight average molecular weight of 22,000 or more and 32,000 or less.   The polycarbonate fiber according to any one of claims 1 to 5, wherein the single fiber fineness is 1 dtex or more and 20 dtex or less.   The polycarbonate fiber according to any one of claims 1 to 6, wherein the single fiber strength is 0.85 cN / dtex or more.   The polycarbonate fiber according to any one of claims 1 to 7, wherein the polycarbonate fiber contains a flame retardant, and the flame retardant is contained in the polycarbonate fiber at a ratio of 5% by mass or more and 30% by mass or less.   The polycarbonate fiber according to any one of claims 1 to 8, which is used for a fiber-reinforced plastic. It is a manufacturing method of the polycarbonate fiber according to any one of claims 1 to 9,
Prepare a polycarbonate resin having a number average molecular weight (Mn) before spinning of 9000 or more and 16000 or less and a weight average molecular weight (Mw) of 22,000 or more and 36000 or less before spinning, or a mixture containing 50% by mass or more of the polycarbonate resin. Process,
A step of melt-spinning the polycarbonate resin or a mixture containing the polycarbonate resin in an amount of 50% by mass or more at a temperature of 250 ° C. or more and 350 ° C. or less to form a spun filament; Including a step of attaching a fiber treatment agent at a ratio of 0.05 parts by mass or more and 3 parts by mass or less per part,
The production of a polycarbonate fiber, wherein the fiber treating agent contains at least 70% by mass of one or more anionic surfactants selected from the group consisting of an alkyl phosphate ester salt and a polyoxyethylene alkyl ether phosphate. Method. The mixture contains a condensed phosphate ester in addition to the polycarbonate resin,
The method for producing a polycarbonate fiber according to claim 10, wherein the condensed phosphate ester is contained in the mixture in an amount of 5% by mass or more and 30% by mass or less. A polycarbonate fiber according to any one of claims 1 to 9, and a sheet for fiber-reinforced plastics containing reinforcing fibers,
The fiber-reinforced plastic sheet contains 23.5 to 80% by mass of reinforcing fiber and 20 to 76.5% by mass of polycarbonate fiber when the mass of the sheet for fiber-reinforced plastic is 100% by mass. A sheet for fiber reinforced plastic.   The fiber-reinforced plastic sheet according to claim 12, wherein the reinforcing fiber has a fiber length of 2 mm or more and 150 mm or less.   The sheet for a fiber-reinforced plastic according to claim 12 or 13, wherein the reinforcing fibers are at least one selected from the group consisting of carbon fibers and aromatic polyamide fibers. Fiber reinforced plastic containing reinforced fibers and matrix resin,
The fiber-reinforced plastic, when the volume of the fiber-reinforced plastic is 100% by volume, contains a reinforcing fiber in a ratio of 22% by volume or more and 75% by volume or less,
The fiber-reinforced plastic, wherein the matrix resin is obtained by melting the polycarbonate fiber according to any one of claims 1 to 9, and contains the polycarbonate resin in an amount of 50% by mass or more.   The fiber reinforced plastic according to claim 15, wherein the polycarbonate resin contained in the matrix resin has a number average molecular weight of 8,000 to 15,000 and a weight average molecular weight of 20,000 to 30,000.   17. The fiber-reinforced plastic according to claim 15, wherein the reinforcing fibers are at least one selected from the group consisting of carbon fibers and aromatic polyamide fibers.