Method for manufacturing molded article

Patent metadata

Field	Value
Publication number	US-11590716-B2
Application number	US-201917040757-A
Country	US
Kind code	B2
Filing date	Mar 27, 2019
Priority date	Mar 30, 2018
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

A method is described for manufacturing a molded product having a recessed/protruding part from a molded substrate (A) including reinforcing fibers and a matrix resin by press molding, the method comprising: a step (I) of placing the molded substrate (A) between molds including an upper mold and a lower mold and deforming the molded substrate (A) in an in-plane direction by heating and pressing the molds; and a step (II) of deforming the molded substrate (A) in an out-of-plane direction by depressurizing the molds subsequent to the step (I), wherein a deformation rate ratio T represented by the following formula (1) is within a range of 0.1 to 1:

T=X/Z   (1)

where X and Z are as defined.

First claim

The invention claimed is:

1. A method for manufacturing a molded product having a recessed/protruding part from a molded substrate (A) including reinforcing fibers and a matrix resin by press molding,
the method comprising:
a step (I) of placing the molded substrate (A) in one of molds including an upper mold and a lower mold and deforming the molded substrate (A) in an in-plane direction by heating the molded substrate and pressing the molded substrate in the mold; and
a step (II) of deforming the molded substrate (A) deformed in the in-plane direction in an out-of-plane direction by depressurizing the mold subsequent to the step (I),
a step (III) of calculating a deformation ratio T using the following formula, wherein the deformation ratio T is within the range 0.1 to 1:
T=X/Z   (1)

an in-plane deformation rate X={(a surface area of a recessed part of the mold having the recessed part)/(a projected area of an opening of the recessed part of the mold having the recessed part, the opening being projected in the out-of-plane direction of the molded substrate (A), which is a raw material)} 1/2 ,
an out-of-plane deformation rate Z=(a maximum thickness of the molded product)/(a thickness P of the molded substrate (A)),
the thickness P=(a mass of the molded substrate (A))/(an apparent density)/(an area of the molded substrate (A)).

2. The method for manufacturing a molded product according to claim 1 , wherein the out-of-plane deformation rate Z is 1.5 or more.

3. The method for manufacturing a molded product according to claim 1 , wherein the molded substrate (A) is obtained by laminating a plurality of molded substrates including the reinforcing fibers and the matrix resin.

4. The method for manufacturing a molded product according to claim 1 , further comprising a step (0) of heating the molded substrate (A) to a melting temperature Ta of the matrix resin or higher before the step (I).

5. The method for manufacturing a molded product according to claim 1 , further comprising a step (IV) of cooling the molded substrate (A) to a melting temperature Ta of the matrix resin−10° C. or lower simultaneously with the step (II) or after completion of the step (II).

6. The method for manufacturing a molded product according to claim 1 , wherein the molded substrate (A) is molded by gripping at least two places in at least one layer thereof.

7. The method for manufacturing a molded product according to claim 1 ,
wherein:
the molded substrate (A) is in a sheet form; and
an area of the molded substrate (A) is equal to or greater than the projected area of the recessed part of the mold in the out-of-plane direction of the molded substrate (A).

8. The method for manufacturing a molded product according to claim 1 , wherein, when a maximum linear distance in the opening of the recessed part of the mold in a cross section of the mold is L, and a depth of the recessed part is D, D/L>0.2 is set.

9. The method for manufacturing a molded product according to claim 1 ,
wherein the reinforcing fibers are carbon fibers, and have a mass average fiber length of 1 to 15 mm.

10. The method for manufacturing a molded product according to claim 1 , wherein the reinforcing fibers are in a nearly monofilament form.

11. The method for manufacturing a molded product according to claim 1 , wherein the reinforcing fibers are randomly dispersed.

12. The method for manufacturing a molded product according to claim 1 , wherein the matrix resin is a thermoplastic resin.

13. The method for manufacturing a molded product according to claim 1 , wherein the molded product has voids, and the voids are included in the molded product in a rate within a range of 10 to 97% by volume.

14. The method for manufacturing a molded product according to claim 1 , wherein, when a bending elastic modulus of the molded product is Ec and a density of the molded product is ρ, specific bending stiffness represented by Ec 1/3 ·ρ −1 is within a range of 3 to 20, and the bending elastic modulus Ec of a portion is 3 GPa or more.

15. The method for manufacturing a molded product according to claim 1 , wherein
an elongation rate Y of the molded substrate (A) before and after the pressing satisfies following formula (2):
X≥Y>1   (2).

Assignees

• Toray Industries

Inventors

• Shinohara Kotaro
• Honma Masato
• Takebe Yoshiki

Classifications

• B29C43/006 Primary

  Pressing and sintering powders, granules or fibres · CPC title

• B29C51/08

  Deep drawing or matched-mould forming, i.e. using mechanical means only · CPC title

• B29C70/16

  using fibres of substantial or continuous length {(non-woven fabrics per se D04H3/00)} · CPC title

• B29C43/52

  Heating or cooling · CPC title

• B29C43/021

  characterised by the shape of the surface · CPC title