Polylactic acid resin composition, process for producing the same, biaxially stretched polylactic acid film, and molded articles thereof

• US 20070032577A1
• Filed: 02/10/2004
• Published: 02/08/2007
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: Toray Industries Incorporated
• Original Assignee: Toray Industries Incorporated
• Inventors: Yoshida, Minoru, Kobayashi, Sadayuki, Kumaki, Jiro, Sakida, Fumie, Kanzawa, Takeshi
• Granted Patent: US 7,718,718 B2
• Time in Patent Office: Days
• US Class Current: 524/31
• CPC Class Codes: C08J 2367/04 Polyesters derived from hydroxy carboxylic acids, e.g. lactones C08J2367/06 takes precedence
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08L 1/10 Esters of organic acids , i.e. acylates
• CPC Class Codes: C08L 25/18 Homopolymers or copolymers of aromatic monomers containing elements other than carbon and hydrogen
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• CPC Class Codes: C08L 2666/26 Natural polymers, natural resins or derivatives thereof according to C08L1/00 - C08L5/00, C08L89/00, C08L93/00, C08L97/00 or C08L99/00
• CPC Class Codes: C08L 33/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08L 33/10 Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

The invention provides a resin composition containing poly(lactic acid) and a cellulosic ester, which are biomass type materials; a resin composition excellent in transparency, mechanical properties, and thermostability; a biaxially drawn film containing poly(lactic acid) and at least one compound selected from cellulosic esters, poly(meth)acrylates, and polyvinyl compounds having a glass transition temperature of 60° C. or higher; and a biaxially drawn film excellent in transparency, mechanical properties, and thermostability. The aims of the invention can be achieved by a resin composition obtained by melt-kneading a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and a cellulosic ester; a resin composition excellent in transparency and having luminous transmittance of 40% or higher for visible light with 400 nm; its production method; a molded article and a film made of the resin composition; a poly(lactic acid) biaxially drawn film containing a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and at least one compound selected from cellulosic esters, poly(meth)acrylates, and polyvinyl compounds having a glass transition temperature of 60° C. or higher; a poly(lactic acid) biaxially drawn film excellent in transparency and having film haze of 10% or lower; and a molded article made of the film.

Claims

1. A poly(lactic acid) polymer composition containing (A) a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and (B) a cellulosic ester.

2. The poly(lactic acid) polymer composition according to claim 1 having a luminous transmittance of 40% or higher for visible light with 400 nm.

3. The poly(lactic acid) polymer composition according to claim 1, wherein the (A) poly(lactic acid) polymer and the (B) cellulosic ester are solvated and/or have a phase structure with 0.01 μ

m or smaller in the poly(lactic acid) polymer composition.

4. The poly(lactic acid) polymer composition according to claim 1 having a both continuous phase structure with 0.01 to 3 μ

m structure period or a dispersion structure with 0.01 to 3 μ

m inter-particle distance.

5. The poly(lactic acid) polymer composition according to claim 1, wherein the (B) component is at least one cellulosic ester selected from a group consisting of cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate phthalate.

6. The poly(lactic acid) polymer composition according to any of claims 1 to 5 further containing one or more kinds of (C) salvation agents for improving the compatibility of the poly(lactic acid) polymer and cellulosic esters.

7. A production method of the poly(lactic acid) polymer composition according to claim 1, comprising melt-kneading (A) a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and (B) a cellulosic ester.

20. A molded article made of poly(lactic acid) polymer composition according to claim 2.

21. A molded article made of poly(lactic acid) polymer composition according to claim 3.

22. A molded article made of poly(lactic acid) polymer composition according to claim 4.

23. A molded article made of poly(lactic acid) polymer composition according to claim 5.

24. A molded article made of poly(lactic acid) polymer composition according to claim 6.

8. A poly(lactic acid) biaxially drawn film containing (A) a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and (B) at least one compound selected from cellulosic esters, poly(meth)acrylates, and polyvinyl compounds having a glass transition temperature of 60°

C. or higher.

9. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the (A) component and the (B) component are solvated and/or have a phase structure with 0.01 μ

m or smaller.

10. The poly(lactic acid) biaxially drawn film according to claim 8 made of poly(lactic acid) polymer composition having a both continuous phase structure with 0.01 to 3 μ

m structure period or a dispersion structure with 0.01 to 3 μ

m inter-particle distance.

11. The poly(lactic acid) biaxially drawn film according to claim 8 having a degree of crystallinity 50% or higher.

12. The poly(lactic acid) biaxially drawn film according to claim 8 having a film haze value on the basis of 10 μ

m thickness 10% or lower.

13. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the content of the (B) component is in a range of 1% by weight or more and less than 50% by weight in the total content of the (A) component and the (B) component.

14. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the celulosic ester of the (B) component is a cellulosic ester obtained by terminating hydroxyl groups of the cellulose with an esterification agent having 1 to 10 carbon atoms.

15. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the celulosic ester of the (B) component is at least one kind cellulosic ester selected from a group consisting of cellulose diacetate, cellulose triacetate, and cellulose acetate propionate.

16. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the poly(meth) acrylate of the (B) component is poly(methyl methacrylate).

17. The poly(lactic acid) biaxially drawn film according to claim 8, wherein the polyvinyl compound of the (B) component is poly(vinyl phenol).

18. The poly(lactic acid) biaxially drawn film according to claim 8 containing one or more kinds of (C) salvation agents for improving the compatibility of the poly(lactic acid) polymer and the (B) component in addition to the (A) and (B) components.

19. A molded article made of poly(lactic acid) polymer composition containing (A) a poly(lactic acid) polymer with a weight average molecular weight of 50,000 or higher and (B) at least one compound selected from cellulosic esters, poly(meth) acrylates, and polyvinyl compounds having a glass transition temperature of 60°

or higher.