Abstract: There is provided a random mat including carbon fibers and a matrix resin, wherein the carbon fibers in the random mat have an average fiber length in a range of 3 mm to 100 mm, a fiber areal weight of the carbon fibers is 25 to 10,000 g/m2, the carbon fibers include a specific carbon fiber bundles having a specific opening degree in a specific amount per the total carbon fibers, and the specific carbon fiber bundles with a thickness of 100 ?m or more are included in a ratio of less than 3% of the number of the total specific carbon fiber bundles.

Abstract: There is provided a random mat including carbon fibers and a matrix resin, wherein the carbon fibers in the random mat have an average fiber length in a range of 3 mm to 100 mm, a fiber areal weight of the carbon fibers is 25 to 10,000 g/m2, the carbon fibers include a specific carbon fiber bundles having a specific opening degree in a specific amount per the total carbon fibers, and the specific carbon fiber bundles with a thickness of 100 ?m or more are included in a ratio of less than 3% of the number of the total specific carbon fiber bundles.

Abstract: There is provided a random mat including carbon fibers having an average fiber length of from 3 mm to 100 mm and a thermoplastic resin, wherein a fiber areal weight of the carbon fibers is from 25 to 10,000 g/m2, a proportion of carbon fiber bundles (A) constituted by single carbon filaments of a critical single fiber number or more defined by the formula (1) to the total amount of fibers in the random mat is from 40 to 99 Vol %, and an average number (N) of fibers in the carbon fiber bundles (A) satisfies the formula (2): critical single fiber number=600/D??(1) 2.0×105/D2?N<8.0×105/D2??(2) wherein D is an average fiber diameter (?m) of carbon fibers.

Abstract: A random mat contains reinforcing fibers having an average fiber length of 3 to 100 mm and a thermoplastic resin, the reinforcing fiber contains reinforcing fiber bundle (A) defined as the bundle composed of the reinforcing fibers of a critical number of single fiber (defined by the following formula (1)) or more, an average thickness of the reinforcing fiber bundles (A) is 100 ?m or less, and the number (n) of the reinforcing fiber bundles (A) per unit weight (g) of the reinforcing fibers satisfies the following formula (I): Critical number of single fiber=600/D (1) (wherein D is the average fiber diameter (?m) of the reinforcing fiber), and 0.65×104/L<N (I) (wherein L is the average fiber length (mm) of the reinforcing fiber).

Abstract: There is provided a fiber-reinforced composite material is constituted by reinforcing fibers with an average fiber length of 5 mm to 100 mm and a thermoplastic resin, in which in a viscoelastic characteristic that is defined by following formulas (1) and (2), an average value in a range of ?25° C. of the melting point of a matrix resin to +25° C. of the melting point of a matrix resin satisfies following formula (3): tan ?=G?/G???(1) tan ??=Vf×tan ?/(100?Vf)??(2) 0.01?tan ???0.2??(3) wherein G? represents a storage modulus (Pa) of the fiber-reinforced composite material, G? represents a loss modulus (Pa) of the fiber-reinforced composite material, and Vf represents a volume fraction (%) of the reinforcing fibers in the fiber-reinforced composite material.

Abstract: A method for manufacturing a reinforcing fiber strand is provided, in which a strand including reinforcing fibers passes through an uneven jig and a widening jig in this order, the uneven jig including a plurality of uneven portions having notched and protrusion portions, and the strand is divided by the protruding portions.

Abstract: There is provided a composite base material, including: carbon fibers having an average fiber length of 3 mm or more and 100 mm or less; and a thermoplastic resin is firmly fixed to the carbon fibers in an amount of 3 to 100 parts by mass with respect to 100 parts by mass of the carbon fibers, wherein a void ratio is more than 7 vol % to less than 100 vol %.

Abstract: A carbon fiber bundle includes carbon fibers and a copolymerized polyolefin attached to the surface of the carbon fibers. The copolymerized polyolefin contains an aromatic vinyl compound and an acid and/or acid anhydride as copolymerization components. The amount of the copolymerized polyolefin attached is 0.01 to 10 parts by mass per 100 parts by mass of the carbon fiber bundle. The carbon fiber bundle may be used or contained in a random mat, a composite material, and various molded articles.

Abstract: There is provided a random mat including carbon fibers having an average fiber length of from 3 mm to 100 mm and a thermoplastic resin, wherein a fiber areal weight of the carbon fibers is from 25 to 10,000 g/m2, a proportion of carbon fiber bundles (A) constituted by single carbon filaments of a critical single fiber number or more defined by the formula (1) to the total amount of fibers in the random mat is from 40 to 99 Vol %, and an average number (N) of fibers in the carbon fiber bundles (A) satisfies the formula (2): critical single fiber number=600/D??(1) 2.0×105/D2?N<8.0×105/D2??(2) wherein D is an average fiber diameter (?m) of carbon fibers.

Abstract: There is provided a method of producing a random mat for manufacturing a thermoplastic composite material, including: slitting continuously a strand including reinforcing fibers in a longitudinal direction of the strand to form a plurality of reinforcing fiber strands with narrow width; cutting the reinforcing fiber strands with narrow width continuously to be an average fiber length of 3 mm to 100 mm to form reinforcing fiber strand pieces; spraying gas onto the cut reinforcing fiber strand pieces for opening the reinforcing fiber strand pieces to form reinforcing fiber bundle pieces; and depositing and fixing the reinforcing fiber bundle pieces onto a breathable support together with a thermoplastic resin in a powder or short fibrous form to form an isotropic random mat in which the reinforcing fibers and the thermoplastic resin are mixed.

Abstract: A method for manufacturing a reinforcing fiber strand is provided, in which a strand including reinforcing fibers passes through an uneven jig and a widening jig in this order, the uneven jig including a plurality of uneven portions having notched and protrusion portions, and the strand is divided by the protruding portions.

Abstract: A random mat contains reinforcing fibers having an average fiber length of 3 to 100 mm and a thermoplastic resin, the reinforcing fiber contains reinforcing fiber bundle (A) defined as the bundle composed of the reinforcing fibers of a critical number of single fiber (defined by the following formula (1)) or more, an average thickness of the reinforcing fiber bundles (A) is 100 ?m or less, and the number (n) of the reinforcing fiber bundles (A) per unit weight (g) of the reinforcing fibers satisfies the following formula (I): Critical number of single fiber=600/D (1) (wherein D is the average fiber diameter (?m) of the reinforcing fiber), and 0.65×104/L<N (I) (wherein L is the average fiber length (mm) of the reinforcing fiber).

Abstract: There is provided a composite base material, including: carbon fibers having an average fiber length of 3 mm or more and 100 mm or less; and a thermoplastic resin is firmly fixed to the carbon fibers in an amount of 3 to 100 parts by mass with respect to 100 parts by mass of the carbon fibers, wherein a void ratio is more than 7 vol % to less than 100 vol %.

Abstract: There is provided a random mat including carbon fibers and a matrix resin, wherein the carbon fibers in the random mat have an average fiber length in a range of 3 mm to 100 mm, a fiber areal weight of the carbon fibers is 25 to 10,000 g/m2, the carbon fibers include a specific carbon fiber bundles having a specific opening degree in a specific amount per the total carbon fibers, and the specific carbon fiber bundles with a thickness of 100 ?m or more are included in a ratio of less than 3% of the number of the total specific carbon fiber bundles.

Abstract: There is provided a random mat of the present invention including: reinforcing fibers having an average fiber length of 5 to 100 mm; and a thermoplastic resin, wherein a fiber areal weight of the reinforcing fibers is from 25 to 3,000 g/m2, for a reinforcing fiber bundle (A) including the reinforcing fibers equivalent to or more than a critical single fiber number defined by formula (1), a ratio of the reinforcing fiber bundle (A) to a total amount of the reinforcing fibers in the mat is from 30 vol % to less than 90 vol %, and an average number (N) of the reinforcing fibers in the reinforcing fiber bundle (A) satisfies formula (2): Critical single fiber number=600/D??(1) 0.7×104/D2<N<1×105/D2??(2) wherein D is an average fiber diameter (?m) of single reinforcing fibers.

Abstract: There is provided a fiber-reinforced composite material is constituted by reinforcing fibers with an average fiber length of 5 mm to 100 mm and a thermoplastic resin, in which in a viscoelastic characteristic that is defined by following formulas (1) and (2), an average value in a range of ?25° C. of the melting point of a matrix resin to +25° C. of the melting point of a matrix resin satisfies following formula (3): tan ?=G?/G???(1) tan ??=Vf×tan ?/(100?Vf)??(2) 0.01?tan ???0.2??(3) wherein G? represents a storage modulus (Pa) of the fiber-reinforced composite material, G? represents a loss modulus (Pa) of the fiber-reinforced composite material, and Vf represents a volume fraction (%) of the reinforcing fibers in the fiber-reinforced composite material.

Abstract: There is provided a random mat of the present invention including: reinforcing fibers having an average fiber length of 5 to 100 mm; and a thermoplastic resin, wherein a fiber areal weight of the reinforcing fibers is from 25 to 3,000 g/m2, for a reinforcing fiber bundle (A) including the reinforcing fibers equivalent to or more than a critical single fiber number defined by formula (1), a ratio of the reinforcing fiber bundle (A) to a total amount of the reinforcing fibers in the mat is from 30 vol % to less than 90 vol %, and an average number (N) of the reinforcing fibers in the reinforcing fiber bundle (A) satisfies formula (2): Critical single fiber number=600/D ??(1) 0.7×104/D2<N<1×105/D2 ??(2) wherein D is an average fiber diameter (?m) of single reinforcing fibers.