Process for producing shaped film

Patent metadata

Field	Value
Publication number	US-11524443-B2
Application number	US-201716078740-A
Country	US
Kind code	B2
Filing date	Feb 24, 2017
Priority date	Feb 24, 2016
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

The method of the present invention for producing a shaped film includes a step of arranging a thermoplastic resin film to divide a space into a first space located on one surface side of the film, and a second space located on the other surface side, a step of heating the thermoplastic resin film, a step of curving the thermoplastic resin film in one space by using a difference in pressure between the first space and the second space, a step of stopping the curving step of the thermoplastic resin film in a state where at least a convex curved surface of both surfaces of the film is exposed into the space, and a step of cooling the curved film.

First claim

The invention claimed is:

1. A process for producing a shaped film, comprising:
a step of arranging a thermoplastic resin film in a first shaping member having a first space which opens to one side, thereby covering an opening, wherein one surface of the thermoplastic resin film is exposed to the first space, wherein the thermoplastic resin film is fixed to an end of the opening of the first shaping member by a fixing member and the thermoplastic resin film is arranged to divide the first space on one surface side of the thermoplastic film from a second space located on the other surface side,
a step of heating the thermoplastic resin film,
a step of curving the thermoplastic resin film into a semispherical shape film into one space by controlling a difference in pressure between the first space and the second space while uniquely determining a radius of curvature of the thermoplastic resin film in accordance with a relationship of the radius of curvature of the thermoplastic resin film with the difference in pressure and an elastic force of the thermoplastic resin film, wherein the thermoplastic resin film is permitted to curve at the end of the opening of the first shaping member and the fixing member,
a step of stopping the curving step of the thermoplastic resin film in a state where at least a convex curved surface of the film is exposed into the space, and
a step of cooling the curved thermoplastic resin film,

wherein the step of curving the thermoplastic resin film comprises:
applying a predetermined difference in pressure between the first space and the second space,
detecting a change in position of the thermoplastic resin film, thereby obtaining the radius of curvature of the thermoplastic resin film,
adjusting the difference in pressure between the first space and the second space, in accordance with a relationship of the difference in pressure with the elastic force of the thermoplastic resin film and the obtained radius of curvature of the thermoplastic resin film, and
applying the adjusted difference in pressure between the first space and the second space.

2. The process for producing a shaped film according to claim 1 ,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film into a lower pressure space than other space by applying pressure in at least one of the first space and the second space.

3. The process for producing a shaped film according to claim 1 ,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film into a lower pressure space than other space by reducing pressure in at least one of the first space and the second space.

4. The process for producing a shaped film according to claim 1 ,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film into the space reduced in pressure by applying pressure in one of the first space or the second space and further reducing pressure in the other space.

5. The process for producing a shaped film according to claim 2 ,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film into the other space by charging a medium into one of the first space or the second space and increasing the inside of the one space in pressure.

6. The process for producing a shaped film according to claim 2 ,
using a shaping die arranged in the first space or the second space, and a medium-supplying unit which supplies a medium to a surface of the shaping die that faces the thermoplastic resin film,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film in a state where the thermoplastic resin film does not contact with the surface of the shaping die by using a difference in pressure which is caused by pressing the thermoplastic resin film with the medium supplied from the medium-supplying unit between the shaping die and the thermoplastic resin film in the first space or the second space.

7. The process for producing a shaped film according to claim 6 ,
wherein the surface of the shaping die that faces the thermoplastic resin film is a substantially semispherical convex surface or concave surface.

8. The process for producing a shaped film according to claim 6 ,
wherein the shaping die comprises a porous material.

9. The process for producing a shaped film according to claim 5 ,
wherein the step of curving the thermoplastic resin film into the other space comprises:
a step of curving the thermoplastic resin film into the other space at a temperature of 30 to 300° C. by charging a heated medium into the first space or the second space to increase the inside of this space in pressure.

10. The process for producing a shaped film according to claim 5 ,
wherein the step of curving the thermoplastic resin film into the other space comprises:
a step of controlling the curve quantity of the thermoplastic resin film on the basis of a position of the thermoplastic resin film that is detected through a position sensor.

11. The process for producing a shaped film according to claim 1 , comprising
a step of reheating the curved thermoplastic resin film after the step of curving the thermoplastic resin film is stopped and before the step of cooling the curved thermoplastic resin film.

12. The process for producing a shaped film according to claim 11 ,
wherein the reheating step is performed at a heating temperature for the heating step or a higher temperature, and the melting point (Tm) of a resin comprised in the thermoplastic resin film or a lower temperature.

13. The process for producing a shaped film according to claim 11 ,
wherein the step of curving the thermoplastic resin film, and the step of reheating the curved thermoplastic resin film are performed as sequential steps in a state where the thermoplastic resin film is put over the first shaping member and the thermoplastic resin film is fixed between the end of the opening in the first shaping member and the fixed member.

14. The process for producing a shaped film according to claim 1 ,
wherein the thermoplastic resin film is selected from polyvinyl alcohol films, polyester films, polyamide films, polyimide films, polyolefin films, polyvinyl chloride films, and polycarbonate films.

15. A process for producing a polarizing film, comprising the steps according to claim 1 , wherein the shaped film is a polarizing film.

16. A process for producing a polarizing lens, comprising:
a step of producing a shaped film according to the process of claim 1 , and
a step of stacking a lens substrate over at least one of both surfaces of a polarizing film.

17. The process for producing a shaped film according to claim 4 ,
wherein the step of curving the thermoplastic resin film comprises:
a step of curving the thermoplastic resin film into the other space by charging a medium into one of the first space or the second space and increasing the inside of the one space in pressure.

18. The process for producing a shaped film according to claim 1 ,
wherein the step of stopping the curving comprises stopping the curving in a state where a portion of the thermoplastic resin film that is not in contact with the first shaping member or the fixing member before the start of the curving is not in contact with either the first shaping member or the fixing member.

19. The process for producing a shaped film according to cl

Assignees

• Mitsui Chemicals Inc
• Hopnic Laboratory Co Ltd

Inventors

• Kamio Hiroyuki
• Aiiso Yoshimitsu

Classifications

• G02B5/3033

  in the form of a thin sheet or foil, e.g. Polaroid · CPC title

• B29C51/46

  Measuring, controlling or regulating · CPC title

• B29K2079/08

  PI, i.e. polyimides or derivatives thereof · CPC title

• B29C51/10 Primary

  Forming by pressure difference, e.g. vacuum · CPC title

• B29K2023/00

  Use of polyalkenes {or derivatives thereof} as moulding material · CPC title