Sheet molding compound and carbon fiber composite material molded article
Provided is a sheet molding compound having excellent thick portion-molding properties that can inhibit the occurrence of internal cracks even during the molding of a thick portion and enables a carbon fiber composite material molded article to be excellently released from a die. Also provided is a carbon fiber composite material molded article. The sheet molding compound of the present invention contains a fiber substrate (A) containing carbon fiber and a thermosetting resin composition (B), in which an average fiber length of the carbon fiber is 5 mm or more, and a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less. Furthermore, the carbon fiber composite material molded article of the present invention has a thick portion having a thickness of 10 mm or more, in which the thick portion is formed of a cured material of the sheet molding compound of the present invention.
1. A sheet molding compound comprising:
a fiber substrate (A) comprising carbon fiber; and
a thermosetting resin composition (B),
wherein the thermosetting resin composition (B) comprises a vinyl ester resin and a shrinkage reducing agent,
wherein the shrinkage reducing agent comprises a polyfunctional (meth)acrylate,
wherein the polyfunctional (meth)acrylate is in liquid state at room temperature, and
wherein an average fiber length of the carbon fiber is 5 mm or more.
2. The sheet molding compound according to claim 1 , wherein a content of the carbon fiber in the sheet molding compound (100 mass %) is 30 mass % or more and 70 mass % or less.
3. The sheet molding compound according to claim 1 , wherein a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less.
4. A carbon fiber composite material molded article comprising a cured material of the sheet molding compound according to claim 1 .
5. The carbon fiber composite material molded article according to claim 4 , wherein the carbon fiber composite material molded article comprises a thick portion having a thickness of 10 mm or more and formed of the cured material.
6. The carbon fiber composite material molded article according to claim 5 , wherein the carbon fiber composite material molded article has a specific gravity of 1.56 or less.
7. A method for producing a carbon fiber composite material molded article, wherein the method comprises heating and compressing the sheet molding compound according to claim 1 by press-molding method.
8. The method according to claim 7 , wherein the carbon fiber composite material molded article comprises a thick portion having a thickness of 10 mm or more and formed of a cured material of the sheet molding compound.
9. A method of producing a sheet molding compound comprising:
preparing a fiber substrate (A) comprising carbon fiber; and
impregnating the fiber substrate (A) with a thermosetting resin composition (B),
wherein the thermosetting resin composition (B) comprises a vinyl ester resin and a shrinkage reducing agent,
wherein the shrinkage reducing agent comprises a polyfunctional (meth)acrylate,
wherein the polyfunctional (meth)acrylate is in liquid state at room temperature, and
wherein an average fiber length of the carbon fiber is 5 mm or more.
10. The method according to claim 9 , the method further comprising thickening the thermosetting resin composition (B) after the impregnating of the fiber substrate (A) with the thermosetting resin composition (B).
11. The method according to claim 9 , wherein a content of the carbon fiber in the sheet molding compound (100 mass %) is 30 mass % or more and 70 mass % or less.
12. The method according to claim 9 , wherein a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less.
13. A sheet molding compound comprising:
a fiber substrate (A) comprising carbon fiber; and
a thermosetting resin composition (B),
wherein the thermosetting resin composition (B) comprises a vinyl ester resin, a shrinkage reducing agent, an unsaturated polyester resin, a polyisocyanate compound, and a reactive diluent,
wherein the reactive diluent comprises one or more selected from the group consisting of a vinyl monomer and a monofunctional (meth)acrylate, and
wherein an average fiber length of the carbon fiber is 5 mm or more.
14. The sheet molding compound according to claim 13 , wherein a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less.
15. The sheet molding compound according to claim 13 , wherein the shrinkage reducing agent comprises a polyfunctional (meth)acrylate.
16. The sheet molding compound according to claim 15 , wherein the polyfunctional (meth)acrylate is in liquid state at room temperature.
17. A carbon fiber composite material molded article comprising a cured material of the sheet molding compound according to claim 13 .
18. A method of producing a sheet molding compound comprising:
preparing a fiber substrate (A) comprising carbon fiber; and
impregnating the fiber substrate (A) with a thermosetting resin composition (B),
wherein the thermosetting resin composition (B) comprises a vinyl ester resin, a shrinkage reducing agent, an unsaturated polyester resin, a polyisocyanate compound, and a reactive diluent,
wherein the reactive diluent comprises one or more selected from the group consisting of a vinyl monomer and a monofunctional (meth)acrylate, and
wherein an average fiber length of the carbon fiber is 5 mm or more.
19. The method according to claim 18 , wherein a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less.
20. The method according to claim 18 , wherein the shrinkage reducing agent comprises a polyfunctional (meth)acrylate.
21. The method according to claim 20 , wherein the polyfunctional (meth)acrylate is in liquid state at room temperature.