JP2006089614A - Carbon fiber strand for thermoplastic resin reinforcement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon fiber strand for thermoplastic resin reinforcement, having excellent adhesiveness to thermoplastic resins and good openability and scratch resistance. <P>SOLUTION: The carbon fiber strand for thermoplastic resin reinforcement is coated with polypropylene, polybutene, an ethylene-propylene copolymer, a propylene-butene copolymer, an ethylene-propylene-butene copolymer or their terminal modified polymers having a number-average molecular weight of 300-2,000 or their mixture. The amount of the polypropylene, etc. applied to the strand is preferably 0.05-5.0 mass% in total based on the carbon fiber. The carbon fiber strand has excellent affinity and adhesiveness to thermoplastic resins, especially polypropylene. A carbon fiber-reinforced thermoplastic resin containing 5-70 mass% carbon fiber strand of the invention has excellent mechanical properties such as interlaminar shear strength. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a carbon fiber strand for reinforcing a thermoplastic resin excellent in adhesiveness with a thermoplastic resin such as polypropylene, excellent in opening property and scratching property, and a carbon fiber reinforced thermoplastic resin reinforced by the carbon fiber strand. About.

  Carbon fiber composite materials (1) High tensile strength and tensile modulus, (2) Excellent heat resistance, chemical resistance, fatigue characteristics, and wear resistance, (3) Low coefficient of linear expansion and dimensional stability It has excellent features such as excellent (4) excellent electromagnetic shielding properties and high X-ray transparency. Therefore, it is widely used for sports / leisure, aviation / space, and general industrial applications. Conventionally, a thermosetting resin such as an epoxy resin has often been used as a matrix resin. Recently, however, a thermoplastic resin has attracted attention as a matrix resin from the viewpoint of recyclability and high-speed moldability.

  A carbon fiber composite material using a thermoplastic resin as a matrix is molded by injection molding of compound pellets, long fiber injection molding of long fiber pellets, injection compression molding, extrusion molding, stamping molding using a random mat, or the like. The carbon fibers used in these moldings have many relatively short fiber forms. For this reason, the mechanical properties such as strength and elastic modulus of the carbon fiber composite material are greatly affected by the affinity and adhesion between the carbon fiber strand and the thermoplastic resin used as the matrix resin.

  Further, for example, in the case of a polyacrylonitrile (PAN) system, the carbon fiber strands are bundled with about 1000 to 50000 bundles of filaments having a diameter of about 7 μm. For this reason, the mechanical properties of the carbon fiber composite material are greatly affected by the state of impregnation of the matrix resin into the carbon fiber strands. In general, the more easily the carbon fibers are opened, the better the resin impregnation property, so that the mechanical properties of the carbon fiber composite material become higher.

  Matrix resins used for carbon fiber reinforced thermoplastic resin composite materials include acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (nylon 6, nylon 66, etc.), polyacetal, polycarbonate, polypropylene, high density polyethylene, polyethylene terephthalate , Polybutylene terephthalate, polyetherimide, polystyrene, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetheretherketone and the like.

  Among these thermoplastic resins, polypropylene is inexpensive and has excellent properties such as moldability, water resistance, chemical resistance (oil resistance, solvent resistance), and electrical insulation. For this reason, polypropylene is expected to grow dramatically in the future as a matrix of a carbon fiber reinforced thermoplastic resin composite material.

  However, since the polypropylene resin has crystallinity and does not have a polar group, the affinity with the carbon fiber is low. For this reason, it is difficult to improve the mechanical properties of the composite material by reinforcing polypropylene with carbon fiber.

  As described above, carbon fiber is an ultrafine filament, and its elongation is small and fluff is likely to occur due to mechanical friction. For this reason, a sizing agent is generally used to improve the handleability of the carbon fiber by improving the bundling property, but the sizing agent is also added to increase the affinity with the matrix resin.

  Many proposals have been made for carbon fiber sizing agents. For example, Patent Document 1 discloses a carbon fiber strand coated with polyurethane. According to Patent Document 1, the carbon fiber strand coated with polyurethane has improved handling properties, and further, a carbon fiber reinforced thermoplastic resin comprising the carbon fiber strand and a highly polar thermoplastic resin such as polycarbonate or polyamide. It is described that the mechanical properties are improved.

  Patent Document 2 discloses a sizing agent containing bisphenol A type epoxy resin that is liquid at normal temperature, bisphenol A type epoxy resin that is solid at normal temperature, an unsaturated polyester resin, and stearic acid as essential components. According to Patent Document 2, it is described that the sizing agent gives good scratch resistance and fiber opening property to the carbon fiber strand, but this sizing agent improves the affinity with the epoxy resin. .

  Thus, these sizing agents are intended to improve adhesion between carbon fiber strands and thermosetting resins such as epoxy resins, or thermoplastic resins having high polarity. Even if the carbon fiber strand to which these sizing agents are added is applied to polypropylene, the strength of the carbon fiber-polypropylene composite material is hardly improved.

  On the other hand, some sizing agents for glass fibers have been proposed that improve the adhesion between glass fibers and polypropylene. For example, Patent Document 3 proposes a sizing agent for glass fiber containing an acid-modified olefin resin and a silane coupling agent having an amino group.

  However, even when this sizing agent is applied to carbon fiber, the reactivity between the carbon fiber and the silane coupling agent is poor, and an effect of improving adhesion cannot be expected. Furthermore, the acid-modified olefin resin is solid at room temperature, and when the sizing agent is applied to the carbon fiber strand, the fiber opening property is impaired. Therefore, although it depends on the molding method, the carbon fiber strands (1000 to 50,000) are used despite the good affinity and adhesion between the sizing agent (acid-modified olefin resin) and the matrix resin (polypropylene resin). There are cases where the matrix resin melted to the inside is not uniformly impregnated and voids are formed in the molded product. In such a case, the high performance cannot be sufficiently reflected in the mechanical properties of the carbon fiber-polypropylene composite material.

For these reasons, there is a demand for the development of a sizing agent for carbon fibers that has excellent affinity between carbon fibers and thermoplastic resins, particularly polypropylene resins, and that is excellent in fiber opening and scratching properties.
JP 58-126375 A (Claims) JP-A-7-197381 (Claims) JP 2003-253563 A (Claims)

  An object of the present invention is to provide a carbon fiber strand for reinforcing a thermoplastic resin, which is excellent in adhesiveness with a thermoplastic resin, excellent in opening property and scratching property, and provided with a sizing agent. Another object of the present invention is to provide a high-strength carbon fiber reinforced thermoplastic resin using the carbon fiber strand as a reinforcing material.

  As a result of diligent research, the present inventors have found that a carbon fiber strand formed by imparting polypropylene, an ethylene-propylene polymer or the like having a predetermined molecular weight that is liquid at room temperature as a sizing agent has an affinity for a thermoplastic resin such as polypropylene. The present invention was found to be high, excellent in openness and scratching properties, and suitable for use as a thermoplastic resin reinforcing material.

  The present invention for achieving the above object is as follows.

  [1] Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, or a terminal-modified polymer thereof having a number average molecular weight of 300 to 2,000 A carbon fiber strand for reinforcing a thermoplastic resin to which a coalescence or a mixture thereof is applied.

  [2] The carbon fiber for reinforcing thermoplastic resin according to [1], wherein the ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer contains 50 mol% or more of propylene monomer units. Strand.

  [3] Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, or a terminal-modified polymer thereof, or a mixture thereof is 0 The carbon fiber strand for reinforcing a thermoplastic resin according to [1] or [2], provided by 0.05 to 5.0% by mass.

  [4] A carbon fiber reinforced thermoplastic resin obtained by blending 5 to 70% by mass of the thermoplastic resin reinforced carbon fiber according to any one of [1] to [3] with a thermoplastic resin.

  [5] The carbon fiber reinforced thermoplastic resin according to [4], wherein the thermoplastic resin is polypropylene.

  The carbon fiber strand of the present invention has high adhesiveness and affinity with a thermoplastic resin such as polypropylene, has less fuzz due to mechanical friction, and has excellent fiber opening properties, and therefore can be suitably used as a reinforcing material for thermoplastic resins. . The carbon fiber reinforced thermoplastic resin obtained by blending the carbon fiber strand with the thermoplastic resin has a high affinity between the polymer adhering to the carbon fiber and the thermoplastic resin, and the carbon fiber strand has an excellent fiber opening property. It has excellent mechanical strength due to good resin impregnation.

  The carbon fiber strand of the present invention is polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, or a terminal-modified polymer thereof having a number average molecular weight. The polymer which is 300-2000, or these mixtures are adhered. All the polymers used in the present invention are fluids having fluidity at room temperature (23 ° C.) within the range of the number average molecular weight of 300 to 2000, and do not contain solids having no fluidity.

  When the number average molecular weight is less than 300, the polymer such as polypropylene to be applied to the carbon fiber strand of the present invention has low heat resistance, and the polymer such as polypropylene evaporates at the time of molding, thereby deteriorating the working environment. On the other hand, when the number average molecular weight exceeds 2000, the viscosity of the polymer increases, so that the openability of the carbon fiber strand is deteriorated, and the drapeability is also lowered, so that the handleability is deteriorated. Further, the friction coefficient of the carbon fiber strand is increased and the scratching property is also deteriorated. The number average molecular weight of the polymer such as polypropylene is preferably 600 to 2000, more preferably 800 to 1800.

  To the carbon fiber strand, polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer or a terminal-modified polymer thereof may be provided alone, or these You may provide the mixture of these. In the case of a mixture, the mixing ratio of polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer and these terminal-modified polymers in the mixture is arbitrary.

  Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-propylene-butene copolymer imparted to carbon fiber strands are selected from monomers appropriately selected from ethylene, propylene, and butene. As an oligomer obtained by a method such as cationic polymerization.

  The content of propylene monomer units in the ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-propylene-butene copolymer is preferably 50 mol% or more, more preferably 70 mol% or more. Preferably, it is more preferably 90 mol% or more.

  Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, or terminal-modified polymer of ethylene-propylene-butene copolymer was modified by introducing -OH or -COOH at the terminal of the polymer. It is a polymer. These terminal-modified polymers can be produced by a known method.

  Since the carbon fiber strand provided with a polymer such as polypropylene is excellent in affinity with a thermoplastic resin such as polypropylene resin, a high-strength composite material can be obtained. In addition, since a polymer such as polypropylene having a molecular weight in the above range has an appropriate viscosity, the carbon fiber strand has a converging property, and the carbon fiber strand can be made to have an arbitrary width by adding a guide action. It can also be opened. Moreover, since it also has a function as a lubricating oil, the abrasion property of the carbon fiber strand is also improved.

  The carbon fiber strand of the present invention may optionally include methyl oleate and dioctyl sebacate as long as the carbon fiber strand that is the effect of the present invention is not damaged, as long as it does not impair the opening property, low friction characteristics, etc. Components such as synthetic lubricants, vegetable oils, higher alcohols such as McCaw alcohol, emulsifiers such as polyethylene glycol type nonionic surfactants and low-sulfated oils, and liquid polyolefin copolymers other than the above-mentioned polypropylene are attached. Also good.

  When a polymer such as polypropylene is applied to the carbon fiber strand, the polymer can be dissolved in a solvent or dispersed in water.

  The adhesion amount of a polymer such as polypropylene varies depending on the molding method and application of the intended composite material, but is preferably 0.05 to 5% by mass in total with respect to the unsized carbon fiber. It is especially preferable to set it as 1-5 mass%. When the adhesion amount is less than 0.05% by mass, the handleability of the carbon fiber is inferior when the composite material is molded. On the other hand, if it exceeds 5% by mass, the amount of polypropylene or the like compatible with the matrix resin increases, and the elastic modulus of the matrix resin tends to decrease.

  Hereinafter, an example of the manufacturing method of the carbon fiber strand of this invention is demonstrated.

[Raw material carbon fiber]
As the raw material carbon fiber used in the present invention, any carbon fiber such as polyacrylonitrile (PAN), petroleum / coal pitch, rayon, and lignin can be used. In particular, PAN-based carbon fibers using PAN as a raw material are preferable because they are excellent in productivity and mechanical properties on an industrial scale.

  The PAN-based carbon fiber strand is a bundle of about 1000 to 50000 filaments having a diameter of 6 to 8 μm, and is manufactured through the following four steps.

[Flame resistance process]
In the first flameproofing step, the acrylic fiber is heated in an air atmosphere at 200 to 300 ° C., the nitrile group is closed, oxygen is introduced into the acrylic polymer, and a stable structure is obtained even at high temperatures.

[Carbonization process]
In a carbonization process, it is set as the carbon fiber strand which baked at 1000 degreeC or more in inert gas atmosphere, and raised the carbon content rate to 90 mass% or more.

[Surface treatment process]
In the surface treatment step, an oxygen-containing functional group for enhancing the adhesiveness with the matrix resin is introduced on the surface of the carbon fiber constituting the strand.

  Examples of the carbon fiber surface treatment include chemical liquid oxidation / electrolytic oxidation in a liquid phase, gas phase oxidation, and the like. Among these surface treatments, an electrolytic oxidation treatment in a liquid phase is preferable from the viewpoint of productivity and treatment uniformity. Examples of the electrolytic solution used for the electrolytic oxidation treatment include inorganic acids such as sulfuric acid, nitric acid, and hydrochloric acid, inorganic hydroxides such as sodium hydroxide and potassium hydroxide, and inorganic salts such as ammonium sulfate, sodium carbonate, and sodium bicarbonate. Can be mentioned.

  As an index when performing the surface treatment of carbon fiber, it is good to manage by the surface oxygen concentration ratio (O / C) of the carbon fiber that can be measured using X-ray photoelectron spectroscopy (ESCA). It is preferable to perform electrolytic oxidation treatment so as to be 0.05 to 0.4.

[Sizing process]
In the sizing process, a sizing agent containing polypropylene or the like is applied to the carbon fiber strands in order to improve the handleability of the carbon fiber strands and improve the affinity between the carbon fibers and the matrix resin.

  The sizing agent can be used as a sizing solution in the form of an emulsion in which a polymer such as polypropylene is dissolved as it is, dissolved in a solvent, or dispersed in water. Emulsification of polypropylene or the like can be performed by a known method.

  Examples of sizing methods for carbon fiber strands include spraying, roller dipping, and roller transfer. Among these sizing methods, a roller dipping method excellent in productivity and uniformity is preferable. When dipping the carbon fiber strand in the sizing liquid, it is important to repeat the opening and drawing through an immersion roller provided in the sizing bath and impregnate the sizing liquid into the strand.

  When an emulsion such as polypropylene is used, a sizing liquid is impregnated between carbon fibers, and then moisture is removed by a subsequent drying process to obtain a target carbon fiber strand. Adjustment of the adhesion amount of polypropylene or the like to the carbon fiber strand is performed by adjusting the concentration of the sizing liquid or adjusting the squeezing roller. For drying the carbon fiber strand, for example, hot air, a hot plate, a roller, an infrared heater or the like can be used.

  The carbon fiber strand of the present invention is suitable as a reinforcing fiber for thermoplastic resin. Thermoplastic resins include acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (nylon 6, nylon 66, etc.), polyacetal, polycarbonate, polypropylene, high density polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyetherimide, polystyrene , Polyethersulfone, polyphenylene sulfide, polyetherketone, polyetheretherketone and the like, and polypropylene is particularly preferable.

  The content of the carbon fiber strand in the carbon fiber reinforced thermoplastic resin varies depending on the form of the carbon fiber, the molding method of the composite material, the use, etc., but is preferably in the range of 5 to 70% by mass from the viewpoint of cost performance. 40 mass% is more preferable.

  When the carbon fiber strand of the present invention is used for molding a carbon fiber reinforced thermoplastic resin composite material, it can be processed into a short fiber compound, a long fiber pellet, a random mat, a bulk molding compound, a unidirectional reinforced prepreg and the like.

  Under the conditions described in the following examples and comparative examples, carbon fiber strands having a sizing agent attached thereto were produced. Various physical property values were measured by the following methods using carbon fiber strands to which each sizing agent was adhered. The results are shown in Tables 1 and 2.

[Measurement method of sizing agent adhesion]
About 5 g of carbon fiber strands to which the sizing agent was adhered were sampled and the mass (W ₁ ) was measured. After measuring the mass (W ₂ ) of the crucible made constant in advance, the carbon fiber strand was put in the crucible, and heat treatment was performed for 30 minutes in a hot air circulation dryer maintained at 450 ° C. ± 5 ° C. in a nitrogen atmosphere. . The crucible was put in a desiccator and cooled to room temperature, and the mass (W ₃ ) of the crucible containing the carbon fiber strands was measured. The sizing agent adhesion amount is expressed by the following formula (i)
Sizing agent adhesion amount (%) = (W ₁ + W ₂ −W ₃ ) / (W ₃ −W ₂ ) × 100 (i)
Determined by

[Method for measuring the amount of fuzz of carbon fiber strands]
Five chrome-plated stainless steel round bars 3 having a diameter of 2 mm were arranged in a zigzag as shown in FIG. The interval between the stainless steel round bars 3 was set to 15 mm, and the carbon fiber strands 1 that had been sized were arranged so that the folding angle α was 120 °. The carbon fiber strands 1 sized between stainless steel round bars were hung in a zigzag manner and rubbed from the bobbin with the carbon fiber strand unwinding tension set to 1.96 N (200 gf).

  The carbon fiber strand after rubbing is sandwiched between two urethane sponges (dimensions 32 mm × 64 mm × 10 mm, mass 0.25 g), and a 125 g weight is placed on the entire surface of the urethane sponge so that a load is applied. The mass of fluff adhering to the sponge when it was passed for 2 minutes at a speed of minutes was taken as the amount of fuzz.

[Method for evaluating the spreadability of carbon fiber strands]
A chrome-plated stainless steel round bar 23 having a diameter of 15 mm, a width measuring device 27, and a package 25 around which a carbon fiber strand is wound are arranged as shown in FIG. 2, and the carbon fiber strand 21 is sewn on the stainless steel round bar 23. Passed through.

  The carbon fiber strand 21 was run at a speed of 5 m / min while adjusting the strand tension so that the strand tension when passing through the width measuring device 27 was 200 gf. The spreading width of the carbon fiber strand 21 at this time was measured with a width measuring device 27. The measurement time and the measurement interval were 30 seconds and 2 seconds / time, respectively, and the average value was the spread width of the carbon fiber strand.

[Interlaminar shear strength of carbon fiber reinforced polypropylene moldings]
Carbon fiber reinforced strand prepregs were produced by impregnating polypropylene into carbon fiber strands provided with a sizing agent using the apparatus shown in FIG.

  The carbon fiber strand 31 provided with a sizing agent is continuously immersed at 30 cm / min in a polypropylene resin bath 39 (width 10 cm × length 30 cm) set in a thermostatic chamber 38 maintained at 260 ° C. After surplus resin was squeezed out by the squeezing roller 34, it was wound up by a winder 37. The mass content of carbon fibers in the obtained carbon fiber reinforced strand prepreg was 30%. In FIG. 3, 32 is a guide roller, 33 is an immersion roller, and 35 is a carbon fiber strand package.

The obtained carbon fiber reinforced strand prepreg was formed into a sheet shape with the orientation direction of the carbon fiber strands aligned in one direction, and 20 carbon fiber strand orientation directions were made the same between the sheets and laminated in a mold. The carbon fiber reinforced strand prepreg laminated in the mold was heated at 190 ° C. and 5 kgf / cm ² for 10 minutes under pressure. When heating, excess resin was allowed to flow out of the mold to produce a carbon fiber reinforced plastic (CFRTP) test piece having a width of 10 mm, a thickness of 3 mm, and a length of 22 mm. The carbon fiber volume content of the CFRTP test piece was 60%. An interlaminar shear test (span / thickness ratio = 4, test speed 1.3 mm / min) was performed on five test pieces in accordance with JIS K7078.

Example 1
Liquid polypropylene (PP) having a number average molecular weight of 1100 was dissolved in toluene to prepare a concentration of 30 g / liter. Here, an unsized carbon fiber strand [“BESFITE STS-24K N00” manufactured by Toho Tenax Co., Ltd., diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ), tensile modulus 238 GPa ( 24.3 ton / mm ² )] was continuously dipped, and the sizing agent was impregnated between the filaments. Subsequently, the solvent (toluene) was evaporated through a dryer at 140 ° C. for 3 minutes to obtain carbon fiber strands. The amount of the sizing agent adhering to the carbon fiber strand was 1.2% by mass.

Example 2
A liquid polypropylene emulsion having a number average molecular weight of 1100 (70 parts by mass of liquid polypropylene and 30 parts by mass of polyoxyethylene alkyl ether) was prepared so that the concentration of polypropylene was 120 g / liter. In the same manner as in Example 1, carbon fiber strands were impregnated with a sizing agent. The amount of the sizing agent attached to the carbon fiber strand was 4.1% by mass.

Example 3
A liquid polypropylene having a number average molecular weight of 600 was dissolved in toluene to prepare a concentration of 30 g / liter. In the same manner as in Example 1, a sizing agent was impregnated between the carbon fiber filaments. The amount of the sizing agent attached to the carbon fiber strand was 1.3% by mass.

Example 4
A polyhydroxy polyolefin “Polytail HA” (manufactured by Mitsubishi Chemical Corporation) having a number average molecular weight of 2000 was dissolved in toluene, and the polyhydroxy polyolefin concentration was adjusted to 30 g / liter. Subsequently, a carbon fiber strand impregnated with a sizing agent was obtained in the same manner as in Example 1. The amount of the sizing agent attached to the carbon fiber strand was 1.1% by mass.

Comparative Example 1
A carbon fiber strand was produced by sizing in the same manner as in Example 1 except that a sizing agent obtained by emulsifying bisphenol A type liquid epoxy resin Epicoat 834 (manufactured by Japan Epoxy Resin Co., Ltd.) was used.

Comparative Example 2
Carbon fiber strands were produced in the same manner as in Example 1 except that a sizing agent obtained by emulsifying polyester-based urethane resin HYDRAN HW-301 (manufactured by Dainippon Ink & Chemicals, Inc.) was used.

Comparative Example 3
Butadiene maleic acid copolymer A carbon fiber strand was produced in the same manner as in Example 1 except that a sizing agent obtained by emulsifying Acro Binder BG-7 (manufactured by Sanyo Chemical Industries) was used.

Comparative Example 4
A polyhydroxypolyolefin “Polytail H” (manufactured by Mitsubishi Chemical Corporation) having a number average molecular weight of 2700 was dissolved in toluene to prepare a polyhydroxypolyolefin concentration of 30 g / liter. Subsequently, a carbon fiber strand impregnated with a sizing agent was obtained in the same manner as in Example 1. The amount of the sizing agent attached to the carbon fiber strand was 1.1% by mass.

  Polytail HA and polytail H are represented by the following two monomer units (a) and (b)

The structure has a structure in which hydroxyl groups are bonded to both ends of the polyolefin main chain. The ratio ((a) / (b)) of (a) and (b) contained in the main chain is 1/9 for polytail HA and 8/2 for polytail H.

  Since the carbon fiber strands of Examples 1 to 4 had a low amount of fuzz and had an appropriate level of convergence, the fibers spread well under tension. Moreover, since the affinity between the sizing agent and polypropylene was good, the resin impregnation was good despite the short immersion time, and the carbon fiber reinforced polypropylene molded product showed high interlayer shear strength.

  The carbon fiber strands of Comparative Examples 1 and 2 had good scuffing and spreading properties, but the affinity between the epoxy resin, urethane resin and polypropylene resin was not good. The shear strength remained low.

  In Comparative Examples 3 and 4, the affinity between the butadiene maleic acid copolymer, polyhydroxypolyolefin and polypropylene is good, but since all the polymers are solid at room temperature and the spread width of the carbon fiber strand is small. The resin impregnation property was slightly inferior, and the interlaminar shear strength of the carbon fiber reinforced polypropylene molded product remained at a slightly low value.

It is the schematic which shows the apparatus for a rubbing fluff amount measurement used in the Example. It is the schematic which shows the apparatus for a fiber-opening property used in the Example. It is the schematic which shows the apparatus used for manufacture of the carbon fiber reinforcement strand prepreg in an Example.

Explanation of symbols

1, 21, 31 Carbon fiber strand 3, 23 Stainless steel round bar 25, 35 Package 27 Width measuring device 32 Guide roller 33 Immersion roller 34 Drawing roller 37 Winder 38 Constant temperature bath 39 Resin bath

Claims (5)

Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, or a terminal-modified polymer thereof having a number average molecular weight of 300 to 2000, or Carbon fiber strands for reinforcing thermoplastic resins to which these mixtures are applied. The carbon fiber strand for reinforcing a thermoplastic resin according to claim 1, wherein the ethylene-propylene copolymer, the propylene-butene copolymer, and the ethylene-propylene-butene copolymer contain 50 mol% or more of propylene monomer units. Polypropylene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, or terminal-modified polymers thereof, or a mixture thereof is 0.05 to The carbon fiber strand for reinforcing a thermoplastic resin according to claim 1 or 2, wherein 5.0% by mass is applied. A carbon fiber reinforced thermoplastic resin obtained by blending the thermoplastic resin-reinforced carbon fiber strand according to any one of claims 1 to 3 with a thermoplastic resin in an amount of 5 to 70 mass%. The carbon fiber reinforced thermoplastic resin according to claim 4, wherein the thermoplastic resin is polypropylene.

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