INJECTION MOULDABLE COMPOSITION

Abstract

An injection mouldable composition includes polyester, polyvinyl acetate and lubricant, to a method of injection moulding the composition, and to an injection moulded article including the composition. The composition includes 30-94 wt % polyester; 5-45 wt % polyvinyl acetate; 1-10 wt % lubricant, and optionally up to 64 wt % additives, the total of polyester, polyvinyl acetate, lubricant and additives adding up to 100 wt %. The polyester has a MFR when measured according to ISO 1133 (210? C. and 2.16 kg) of more than 20 g/10 min.

Claims

1. An injection mouldable composition comprising: 30-94 wt % polyester; 5-45 wt % polyvinyl acetate; 1-10 wt % lubricant; optionally up to 64 wt % additives; wherein the total of polyester, polyvinyl acetate, lubricant and additives adding up to 100 wt %; and wherein the polyester has a MFR when measured according to ISO 1133 (210? C. and 2.16 kg) of more than 20 g/10 min, preferably more than 22 g/10 min, more preferably more than 24 g/10 min, most preferably more than 25 g/10 min.

2. The composition according to claim 1, wherein the polyester has a MFR of more than 26 g/10 min, preferably more than 28 g/10 min, more preferably more than 30 g/10 min, most preferably more than 32 g/10 min when measured according to ISO 1133 (210? C. and 2.16 kg).

3. The composition according to claim 1, wherein the polyester is chosen from the group consisting of polylactic acid, polyglycolic acid, polybutylene succinate, polybutylene adipate terephthalate, polyhydroxyalkanoate, polycaprolactone, and copolymers and/or mixtures thereof.

4. The composition according to claim 1, wherein the polyester is biobased.

5. The composition according to claim 1, wherein the polyester is biodegradable.

6. The composition according to claim 1, wherein the polyester is polylactic acid.

7. The composition according to claim 1, wherein the polyvinyl acetate has a weight average molecular weight (Mw) ranging between 5,000 and 500,000 g/mol, preferably between 7,500 and 250,000 g/mol, and most preferably between 10,000 and 150,000 g/mol.

8. The composition according to claim 1, wherein the polyvinyl acetate is biobased.

9. The composition according to claim 1, wherein the polyvinyl acetate is a copolymer of vinyl acetate with a further acid vinyl ester.

10. The composition according to claim 1, wherein the polyvinyl acetate is a copolymer of vinyl acetate and vinyl laurate.

11. The composition according to claim 1 any one of the preceding claims, wherein the lubricant comprises a fatty acid or fatty acid ester.

12. The composition according to claim 1, wherein the lubricant is chosen from the group consisting of epoxidized soybean oil, epoxidized linseed oil, lauric acid, stearic acid and combinations thereof, preferably wherein the lubricant is epoxidized linseed oil.

13. The composition according to claim 1, wherein the composition has an E-modulus according to ISO 527-1 which is higher than 0.8 GPa, preferably higher than 1.0 GPa, more preferably higher than 1.5 GPa.

14. The composition according to claim 1, wherein the composition has a spiral flow of more than 90 cm, preferably more than 100 cm, most preferably more than 110 cm, as measured in a Sumitomo DEMAG IntElect2 75/420-250 injection moulding machine operating at the conditions described in the specification.

15. The composition according to claim 1, wherein the composition has a Tg of at least 40? C., preferably at least 45? C., most preferably at least 50? C. as determined in accordance with ASTM D3418.

16. A method for producing an injection moulded article, comprising the steps of: a) blending a composition according to claim 1, and b) injection moulding the blend into an article.

17. An injection moulded article comprising the composition according to claim 1.

18. The article according to claim 17, wherein the article is a container, preferably a food container.

19. The container according to claim 18 having a wall thickness of less than 0.8 mm, preferably of 0.5-0.8 mm, and a maximum flow path to wall thickness ratio of more than 200.

20. The article according to claim 17, wherein the article is transparent.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0123] FIG. 1 is a schematic picture of a rectangular thin walled plastic container.

[0124] FIG. 2 is a schematic picture of a cylindrical thin walled container.

[0125] FIG. 3 is a schematic picture of a cross-section of the container of FIG. 2.

[0126] FIG. 4 is a graph of spiral flow vs. MFI (MFR) for various compositions.

[0127] FIG. 5 is a photograph of the incomplete container resulting from injection moulding 95 wt % PLA NW 3251D and 5 wt % MR S533.

[0128] FIG. 6 is photograph of the complete container resulting from injection moulding a composition of 78.5 parts by weight NW3251D, 15 parts by weight Vinnex 8880 and 6.5 parts by weight Lankroflex E2307 and subsequently dry blended with 5 wt % MR S533.

DETAILED DESCRIPTION OF FIGS. 1-3

[0129] The plastic container 1 in FIG. 1 has a bottom 2, four side walls 3, and an open top 4. The side walls 3 have a thickness and extend from the edges of the bottom 2 to the open top 4. The side walls have an upper portion 5 which may have a thickness that is different from the thickness of the rest of the side walls, and the upper portion 5 may be configured to receive a lid. The bottom has a centre 6. The maximum flow path in this case is defined as the path from the centre of the bottom to outer flange corner 7, as defined by line 8.

[0130] In an alternative embodiment, shown in FIG. 2 and FIG. 3, the plastic container 1 may have a circular circumference. In this case, the maximum flow path is defined by line 8 extending from centre 6 to outer circumference of upper portion 5, which has been drawn to be flange shaped.