US 11,939,465 B2
Prepreg and production method therefor, slit tape prepreg, carbon fiber-reinforced composite material
Hiroshi Kobayashi, Ehime (JP); Taiki Maeyama, Ehime (JP); Daisuke Kido, Ehime (JP); Takashi Ikushima, Otsu (JP); Naofumi Hosokawa, Nagoya (JP); and Hirokazu Ohnishi, Tokyo (JP)
Assigned to Toray Industries, Inc., Tokyo (JP)
Appl. No. 17/253,205
Filed by Toray Industries, Inc., Tokyo (JP)
PCT Filed Mar. 27, 2019, PCT No. PCT/JP2019/013096
§ 371(c)(1), (2) Date Dec. 17, 2020,
PCT Pub. No. WO2020/003662, PCT Pub. Date Jan. 2, 2020.
Claims priority of application No. 2018-120566 (JP), filed on Jun. 26, 2018.
Prior Publication US 2021/0363316 A1, Nov. 25, 2021
Int. Cl. C08L 63/00 (2006.01); C08J 5/24 (2006.01)
CPC C08L 63/00 (2013.01) [C08J 5/243 (2021.05); C08J 2363/02 (2013.01); C08J 2477/00 (2013.01); C08J 2481/06 (2013.01); C08L 2205/03 (2013.01)] 9 Claims
 
1. A prepreg comprising components [A] to [E]:
[A] carbon fiber,
[B] epoxy resin,
[C] curing agent,
[D] thermoplastic resin, and
[E] particles containing a thermoplastic resin as primary component and having a volume-average particle diameter of 5 to 50 μm,
the prepreg having a structure incorporating a first layer composed mainly of the component [A] and a first epoxy resin composition containing the components [B] to [D] but substantially free of the component [E] and a second layer composed mainly of a second epoxy resin composition containing the components [B] to [E] and disposed adjacent to each surface of the first layer,
wherein the component [D] of the second epoxy resin composition has a weight-average molecular weight of 2,000 to 30,000 g/mol and accounts for 8 to 15 parts by mass relative to the total quantity of the components [B] to [E] of the second epoxy resin composition, which accounts for 100 parts by mass,
wherein the second epoxy resin composition has a storage elastic modulus G′ at 25° C. of 8.0×105 to 6.0×106 Pa as measured at an angular frequency of 3.14 rad/s, giving a value of 0.085 or more as calculated by the equation (1) below, and showing a glass transition temperature of −10° C. or more and less than 7° C. as measured by differential scanning calorimetry (DSC),

OG Complex Work Unit Math
wherein the component [D] of the first epoxy resin composition and the second epoxy resin composition accounts for 4 parts by mass or more and less than 8 parts by mass relative to the total quantity of the first epoxy resin composition and the second epoxy resin composition, which accounts for 100 parts by mass.