Fiber-reinforced resin molded body and method for producing same

Patent metadata

Field	Value
Publication number	US-2025257179-A1
Application number	US-202318856449-A
Country	US
Kind code	A1
Filing date	Apr 13, 2023
Priority date	Apr 20, 2022
Publication date	Aug 14, 2025
Grant date	—

Abstract

Provided is a fiber-reinforced resin molded body that has continuous voids and includes a carbon fiber nonwoven fabric and a thermosetting resin, in which the continuous voids have a porosity of 50% by volume to 97% by volume, and contact points of discontinuous carbon fibers constituting the carbon fiber nonwoven fabric are immobilized by the thermosetting resin having a substantially spherical shape of 40 μm to 300 μm in diameter. Also provided is a method of producing a fiber-reinforced resin molded body, the method including the following steps in the order mentioned: the preform forming step of forming a preform including a carbon fiber nonwoven fabric in a molding die; the injection preparation step of forming a closed space in which the preform is arranged; the injection step of injecting a liquid thermosetting resin into the closed space; the porosity adjustment step of allowing the carbon fiber nonwoven fabric to expand in the thickness direction; and the curing step of maintaining the preform at a temperature equal to or higher than a curing temperature of the thermosetting resin. According to this method, a fiber-reinforced resin molded body that includes a carbon fiber nonwoven fabric and a thermosetting resin is simply produced.

First claim

1 . A fiber-reinforced resin molded body, having continuous voids and comprising:
a carbon fiber nonwoven fabric; and a thermosetting resin, wherein the continuous voids have a porosity of 50% by volume to 97% by volume, and contact points of discontinuous carbon fibers constituting the carbon fiber nonwoven fabric are immobilized by the thermosetting resin having a substantially spherical shape of 40 μm to 300 μm in diameter.

2 . The fiber-reinforced resin molded body according to claim 1 , wherein the contact points of the carbon fibers constituting the carbon fiber nonwoven fabric are covered with a binder resin and the thermosetting resin in the order mentioned.

3 . The fiber-reinforced resin molded body according to claim 1 , wherein either of a melting point and a glass transition temperature of the binder resin, whichever higher, is equal to or higher than a curing temperature of the thermosetting resin.

4 . The fiber-reinforced resin molded body according to claim 1 , wherein the thermosetting resin contains at least one thermosetting resin selected from the group consisting of epoxy resins, phenol resins, unsaturated polyester resins, and vinyl ester resins.

5 . The fiber-reinforced resin molded body according to claim 1 , wherein the binder resin contains a resin formed of a polymer having at least one functional group selected from the group consisting of an amino group, a carboxyl group, an acid anhydride group, an epoxy group, an imino group, an aryl group, a ketone group, and an isocyanate group.

6 . The fiber-reinforced resin molded body according to claim 1 , wherein the carbon fiber nonwoven fabric contains carbon fibers having a fiber length of 25 mm to 50 mm in a range of 1% by mass or more but less than 50% by mass, and carbon fibers having a fiber length of 0.1 mm or more but less than 25 mm in a range of more than 50% by mass.

7 . The fiber-reinforced resin molded body according to claim 1 , wherein the carbon fiber nonwoven fabric is composed of aggregates of 100 or more but less than 1,000 carbon fiber filaments, and aggregates of 1 or more but less than 100 carbon fiber filaments.

8 . The fiber-reinforced resin molded body according to claim 1 , wherein the carbon fiber nonwoven fabric is composed of discontinuous carbon fibers dispersed in filament units.

9 . The fiber-reinforced resin molded body according to claim 1 , having a length of 0.1 m to 5 m and a width of 0.1 m to 1.5 m.

10 . A structural member comprising the fiber-reinforced resin molded body according to claim 1 , to which a bending load is mainly applied.

11 . A structural member for a mobile object, comprising the fiber-reinforced resin molded body according to claim 9 .

12 . A structural member for a flying object, comprising the fiber-reinforced resin molded body according to claim 9 .

13 . A panel member for acoustic control, in which a surface material is the fiber-reinforced resin molded body according to claim 1 .

14 . A method of producing a fiber-reinforced resin molded body, the method comprising the following steps in the order mentioned:
preform forming step: the step of forming a preform including a carbon fiber nonwoven fabric in a molding die; injection preparation step: the step of forming a closed space in which the preform is arranged; injection step: the step of injecting a liquid thermosetting resin into the closed space; porosity adjustment step: the step of allowing the carbon fiber nonwoven fabric to expand in the thickness direction; and curing step: the step of holding the preform at a temperature equal to or higher than a curing temperature of the thermosetting resin.

15 . The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein, in the injection preparation step, the carbon fiber nonwoven fabric is adjusted to have a porosity of 80% by volume to 97% by volume in the closed space.

16 . The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein, in the porosity adjustment step, the preform injected with the liquid thermosetting resin is adjusted to have a porosity of 10% by volume to 97% by volume.

17 . The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein, in the injection step, the liquid thermosetting resin is injected after being adjusted to have a viscosity of 1 mPa·s to 1,000 mPa·s.
The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein, in the porosity adjustment step, the thickness of the preform is adjusted by controlling the pressure inside the closed space.

19 . The method of producing a fiber-reinforced resin molded body according to claim 18 , wherein, in the porosity adjustment step, the thickness of the preform is adjusted by inducing the carbon fiber nonwoven fabric to spring-back and expand through relaxation of the pressure inside the closed space.

20 . The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein the curing step does not involve pressurization of the preform.

21 . The method of producing a fiber-reinforced resin molded body according to claim 14 , further comprising the pressurization step of pressurizing the preform after the injection step but before the curing step.

22 . The method of producing a fiber-reinforced resin molded body according to claim 14 , wherein, in the preform forming step, a preform in which a reinforcing fiber substrate other than the carbon fiber nonwoven fabric is further laminated as an outermost layer is arranged.

Assignees

• Toray Industries

Inventors

• Takebe Yoshiki
• Kawahara Kota
• Honma Masato

Classifications

• C08J2491/06

  Waxes · CPC title

• C08J2479/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• C08J2461/06

  of aldehydes with phenols · CPC title

• C08J2363/02

  Polyglycidyl ethers of bis-phenols · CPC title

• C08J5/06

  using pretreated fibrous materials · CPC title