Liquid vinyl injection molding method and apparatus
A method is provided for the formation of a molded article comprising the steps of: providing at least one liquid plastisol composition, providing an injection molding apparatus including an injection barrel, feeding the at least one liquid plastisol composition to the injection barrel, heating the at least one plastisol composition within the injection barrel to the fusion temperature of the plastisol, and injecting the at least one plastisol composition to the mold.
1. A method for the formation of a molded article, the method comprising the steps of:
providing at least one liquid plastisol composition, wherein said at least one plastisol composition is comprised of particles of a resin or polymer dispersed in a liquid plasticizer,
providing an injection molding apparatus including an injection barrel and an injection mold,
feeding said at least one liquid plastisol composition to said injection barrel at a temperature below the fusion temperature of said plastisol,
heating said at least one plastisol composition within said injection barrel to at least the fusion temperature of said plastisol,
injecting at a temperature of at least the fusion temperature thereof said at least one plastisol composition from said injection barrel into said injection mold, and
permitting said plastisol to cool within said mold below said fusion temperature to form a molded article.
2. The method of claim 1 , wherein more than one plastisol composition is fed into said injection barrel.
3. The method of claim 1 , wherein said at least one plastisol composition is heated within said injection barrel to a temperature within the range of 150 to 210° C.
4. The method of claim 3 , wherein said at least one plastisol composition is heated within the injection barrel to a temperature of about 180° C.
5. The method of claim 1 , wherein said at least one plastisol composition is comprised of an acrylic resin.
6. The method of claim 1 , wherein said at least one plastisol composition is comprised of a polyvinyl chloride resin.
7. The method of claim 1 , comprising feeding a cross-linking agent to said injection barrel for admixture with said at least one plastisol composition.
8. The method of claim 1 , wherein said at least one plastisol composition is comprised of from about 10 to 15 wt. % of resin or polymer particles.
9. The method of claim 1 , wherein said at least one plastisol composition is comprised of from 10 to 95 wt. % of resin or polymer particles.
10. The method of claim 1 , wherein said at least one plastisol is comprised of from about 40 to 90 wt. % plasticizer.
11. The method of claim 1 , comprising combining at least one additional component with said at least one plastisol composition in said injection barrel selected from the group consisting of fillers, pigments, liquid plasticizers, colorants, UV stabilizers, anti-fungal agents, lubricants, cross-linking agents, and processing aids.
12. The method of claim 1 , comprising feeding said at least one liquid plastisol from said injection barrel to said injection mold by means of a screw conveyor.
13. The method of claim 12 , wherein said screw conveyor has a compression ratio ranging from 1.1:1 to 3:1.
14. The method of claim 13 , wherein said compression ratio ranges from 1.5:1 to 2:1.
15. The method of claim 12 , wherein said compression ratio is 3:1 or less.
16. The method of claim 1 , comprising feeding multiple plastisol compositions to said injection barrel by use of a feed manifold connected to separate plastisol feed streams.
17. The method of claim 1 , comprising feeding multiple plastisol compositions to said injection barrel from different feed means.
18. The method of claim 1 , comprising feeding multiple plastisol compositions to said injection barrel using different inlet ports.
19. The method of claim 1 , comprising feeding said at least one liquid plastisol composition into said injection barrel at ambient temperature.
20. The method of claim 19 , comprising feeding said at least one liquid plastisol composition from said injection barrel to said injection mold by means of a screw conveyor in said injection barrel.
21. The method of claim 20 , wherein said screw conveyor has a compression ratio of 3:1 or less.
22. The method of claim 21 , wherein said compression ratio ranges from 1.1:1 to 3:1.
23. The method of claim 22 , wherein said compression ratio ranges from 1.5:1 to 2:1.
24. The method of claim 19 , wherein said at least one plastisol composition is heated within said injection barrel to a temperature within the range of 150 to 210° C.
25. The method of claim 20 , comprising combining at least one additional component with said at least one plastisol composition in a feed manifold prior to being fed to said injection barrel, said at least one additional component being selected from the group consisting of fillers, pigments, liquid plasticizers, colorants, UV stabilizers, anti-fungal agents, lubricants, cross-linking agents, and processing aids.
26. The method of claim 20 , wherein said at least one plastisol composition is comprised of an acrylic resin.
27. The method of claim 20 , wherein said at least one plastisol composition is comprised of a polyvinyl chloride resin.
28. The method of claim 20 , comprising feeding a cross-linking agent to said injection barrel for admixture with said at least one plastisol composition.
29. The method of claim 20 , wherein said at least one plastisol composition is comprised of from about 10 to 15 wt. % of resin or polymer particles.
30. The method of claim 20 , wherein said at least one plastisol composition is comprised of from 10 to 95 wt. % of resin or polymer particles.
31. The method of claim 20 , wherein said at least one plastisol is comprised of from about 40 to 90 wt. % plasticizer.
32. The method of claim 20 , wherein said at least one plastisol composition is heated within said injection barrel to a temperature within the range of 150 to 210° C.
33. The method of claim 20 , comprising feeding multiple plastisol compositions to said injection barrel by use of a feed manifold connected to separate plastisol feed streams.
34. The method of claim 20 , comprising feeding multiple plastisol compositions to said injection barrel from different feed means.
35. The method of claim 20 , comprising feeding multiple plastisol compositions to said injection barrel using different inlet ports.
36. The method of claim 20 , comprising feeding said at least one liquid feed plastisol into said injection barrel at ambient temperature.