Injection-molded, mineral-filled articles and processes for making the same

• US 20030015824A1
• Filed: 08/26/2002
• Published: 01/23/2003
• Est. Priority Date: 02/12/2001
• Status: Abandoned Application

• Current Assignee: Alan H. Forbes, Wen Pao Wu
• Original Assignee: Alan H. Forbes, Wen Pao Wu
• Inventors: Wu, Wen Pao, Forbes, Alan H.
• Application Number:
  US10/227,977
• Publication Number:
  US 20030015824A1
• Time in Patent Office: Days
• US Class Current: 264/328.18
• CPC Class Codes: A47G 21/00 Table-ware crumb trays A47L13/52; table knives B26B
• CPC Class Codes: B29C 45/0013 using fillers dispersed in the moulding material, e.g. metal particles
• CPC Class Codes: B29K 2709/10 Mica
• CPC Class Codes: B29L 2031/286 Cutlery

Abstract

A process for preparing an injection-molded cutlery The process includes providing a mixture of a filler and a polymer The mixture comprises from about 30 to about 70 wt. % filler and from about 30 to about 70 wt. % polymer The mixture is heated to its melting temperature and then injected into a mold The mixture is cooled so as to form the cutlery The cutlery is ejected from the mold

Claims

1. A process for preparing an injection-molded cutlery, the process comprising

providing a mixture of a filler and a polymer, wherein the mixture is from about 30 to about 70 wt % filler and from about 30 to about 70 wt % polymer;

heating the mixture to its appropriate melting temperature,

injecting the mixture into a mold,

cooling the mixture to form the cutlery, and

ejecting the cutlery from the mold.

2. The process according to claim 1, further comprising providing an injection molding machine having a cavity and a rotating screw, and wherein injecting the mixture into the mold includes drawing the mixture into the cavity by moving the rotating screw in a first direction and wherein injecting the mixture into the mold includes moving the rotating screw in a second direction generally opposite to the first direction

3. The process according to claim 1, wherein the polymer is selected from the group consisting of a polyester, a polyolefin, and an alkenyl aromatic polymer

4. The process according to claim 3, wherein the polymer is a polyethylene terephthalate

5. The process according to claim 3, wherein the polymer is a crystallized polyethylene terephthalate

6. The process according to claim 3, wherein the polymer is a polyethylene

7. The process according to claim 6, wherein the polymer is a high density polyethylene

8. The process according to claim 3, wherein the polymer is a homopolymer polypropylene.

9. The process according to claim 3, wherein the polymer is an ethylene-propylene copolymer

10. The process according to claim 3, wherein the polymer is a polystyrene.

11. The process according to claim 10, wherein the polymer is a high impact polystyrene.

12. The process according to claim 1, wherein the filler is talc, mica, calcium carbonate, barium sulfate, stone dust, or combinations thereof

13. The process according to claim 12, wherein the filler is talc, calcium carbonate, or a combination thereof

14. The cutlery made by the process of claim 1

15. The process according to claim 1, wherein providing a mixture includes providing a polymer, providing a filler, and providing an injection molding machine having a compounding extruder, and mixing the polymer and the filler in the twin screw extruder so as to provide the mixture.

16. The process according to claim 1, wherein providing a mixture includes providing a pre-compounded mixture comprising from about 50 to about 85 wt. % filler and from about 15 to about 50 wt. % polymer

17. The process according to claim 16, further comprising mixing neat polymer with the pre-compounded mixture prior to heating the mixture to its appropriate melting temperature.

18. The process according to claim 1, wherein the flexural modulus of the cutlery is at least 50% greater than that of its neat polymer as determined by ASTM D790

19. The process according to claim 1, wherein the flexural modulus of the cutlery is at least 150% greater than that of its neat polymer as determined by ASTM D790

20. The process according to claim 1, wherein the mixture is from about 40 to about 60 wt. % filler and from about 40 to about 60 wt % polymer

21. The process according to claim 20, wherein the filler is talc and the polymer is one of polystyrene and high impact polystyrene

22. The process according to claim 1, wherein ejecting the cutlery from the mold occurs at a temperature T₂ which is greater than a temperature T₁ at which cutlery formed of neat polymer is ejected from the mold.

24. The process according to claim 23, wherein the mixture is from about 40 to about 60 wt % filler and from about 40 to about 60 wt % polymer

25. The process according to claim 24, wherein the filler is one of talc and calcium carbonate and the polymer is one of polystyrene, polypropylene and high impact polystyrene

27. The process according to claim 26, wherein the mixture is from about 40 to about 60 wt % filler and from about 40 to about 60 wt % polymer

28. The process according to claim 27, wherein the filler is one of talc and calcium carbonate and the polymer is one of polystyrene, high impact polystyrene, and polypropylene

23. A process for forming cutlery, comprising

providing a mixture from about 30 to about 70 wt. % filler and from about 30 to about 70 wt % polymer,

providing an injection-molded machine with a cavity and a rotating screw,

heating the mixture in the injection molding machine to an appropriate temperature to melt the mixture;

moving the rotating screw in a first direction so as to draw the mixture into the cavity of the injection molding machine,

moving the rotating screw in a direction generally opposite to the first direction to inject the mixture into a mold from the cavity,

cooling the mixture to an appropriate temperature in the mold so as to form the cutlery,

opening the mold, and

ejecting the cutlery from the mold

26. A cutlery comprising a filler and a polymeric material, the cutlery including from about 30 to about 70 wt % filler and from about 30 to about 70 wt % polymer, wherein the filler is talc, mica, calcium carbonate, barium sulfate, stone dust, or a combination thereof