초록 ▼

A continuous process provides a devolatilized liquid injection moldable silicone composition. In the process, a filler, treating agent and silicone polymer are introduced into an extruder having a length to diameter ratio of at least greater than 50. The filler, treating agent and silicone elastomer

A continuous process provides a devolatilized liquid injection moldable silicone composition. In the process, a filler, treating agent and silicone polymer are introduced into an extruder having a length to diameter ratio of at least greater than 50. The filler, treating agent and silicone elastomer are continuously compounded in the extruder into a devolatilized liquid injection moldable silicone composition. A system for preparing a liquid silicone rubber composition comprises a mixer to prepare a concentrate of filler and silicone polymer, a long extruder having an L/D ratio of greater than 50, connected to the mixer to receive the concentrate from the mixer and to compound and devolatilize the concentrate, a treating agent and silicone polymer into a liquid silicone rubber composition containing volatiles and a cooler to receive the liquid silicone rubber composition to cool, homogenize and further devolatilized the composition.

대표청구항 ▼

1. A process of preparing a liquid silicone rubber composition, comprising: introducing a filler, treating agent and silicone polymer into an extruder having a length to diameter ratio of at least greater than 70; and continuously compounding and devolatilizing said filler, treating agent and s

1. A process of preparing a liquid silicone rubber composition, comprising: introducing a filler, treating agent and silicone polymer into an extruder having a length to diameter ratio of at least greater than 70; and continuously compounding and devolatilizing said filler, treating agent and silicone polymer into said liquid silicone rubber composition in said extruder. 2. The process of claim 1, wherein said extruder is a co-rotating, intermeshing double screw extruder.3. The process of claim 1, comprising densifying filler with an initial amount of silicone polymer prior to introduction of said filler into said extruder.4. The process of claim 1, further comprising discharging said liquid rubber composition from said extruder to a cooler.5. The process of claim 4, wherein said cooler comprises a counter rotating double screw extruder.6. The process of claim 4, wherein said liquid silicone rubber composition is cooled, homogenized and further devolatilized in said cooler.7. The process of claim 6, wherein said liquid silicone rubber is in residence in said cooler for a period greater than residence in said extruder.8. The process of claim 1, further comprising dividing said liquid silicone rubber composition into a first stream and a second stream.9. The process of claim 8, wherein a platinum catalyst is added to said first stream to produce a component mixture A and a crosslinker is added to said second stream to produce a component mixture B.10. The process of claim 9, wherein said component mixture A and said component mixture B are injected into a mold where they are cured to produce a rubber part.11. The process of claim 1, wherein said filler is a raw, untreated silica.12. The process of claim 1, wherein said filler is a pretreated filler with treating agent.13. The process of claim 12, wherein said treating agent is a silanol-reacting treating agent.14. The process of claim 1, wherein said filler contains silanol groups and said treating agent comprises silanol-stopped polydimethylsiloxane, octamethylcyclotetrasiloxane (D4) or hexamethyldisilazane (HMDZ).15. The process of claim 14, further comprising maintaining an elevated pressure in a section of said extruder while compounding said filler, treating agent and silicone polymer to enhance reaction between said filler and said treating agent.16. The process of claim 15, comprising maintaining a pressure between about 16 and about 400 psi.17. The process of claim 15, comprising maintaining a pressure between about 40 to about 300 psi.18. The process of claim 15, comprising maintaining a pressure between about 100 and about 200 psi.19. The process of claim 1, comprising controlling temperature in said extruder in a feed section (L/D<9) to less than 150° C. and then from said feed section to discharge between about 120 and about 240° C.20. The process of claim 1, comprising controlling temperature in said extruder in a feed section (L/D<9) to less than 120° C. and then from said feed section to discharge between about 130 and about 230° C.21. The process of claim 25, wherein said filler is a raw, untreated silica.22. A process of preparing a silicone composition, comprising: introducing a filler, treating agent and silicone polymer into an extruder having a length to diameter ratio of at least greater than 50; continuously compounding and devolatilizing said filler, treating agent and silicone polymer into said silicone composition in said extruder; and discharging said silicone composition from said extruder to a cooler. 23. The process of claim 22, wherein said cooler comprises a counter rotating double screw extruder.24. The process of claim 22, wherein said silicone composition is cooled, homogenized and further devolatilized in said cooler.25. The process of claim 24, wherein said silicone composition is in residence in said cooler for a period greater than residence in said extruder.26. The process of claim 22, comprising densifying filler with a n initial amount of silicone polymer prior to introduction of said extruder.27. The process of claim 22, further comprising dividing said liquid silicone rubber composition into and a second stream.28. The process of claim 27, wherein a platinum catalyst is added to said first to produce a component mixture A and a crosslinker is added to said second stream to produce a component mixture B.29. The process of claim 28, wherein said component mixture A and said component mixture B are injected into a mold where they are cured to produce a rubber part.30. The process of claim 22, wherein said filler is a pretreated filler with treating agent.31. The process of claim 30, wherein said treating agent is a silicone-reacting treating agent.32. The process of claim 22, wherein said filler contains silanol groups and said treating agent comprises silanol-stopped polydimethylsiloxane, octamethylcyclotetrasiloxane (D4) or hexamethyldisilazane (HMDZ).33. The process of claim 32, further comprising maintaining an elevated pressure in a section of said extruder while compounding said filler, treating agent and silicone polymer to enhance reaction between said filler and said treating agent.34. The process of claim 33, comprising maintaining a pressure between about 16 and about 400 psi.35. The process of claim 33, comprising maintaining a pressure between about 40 to about 300 psi.36. The process of claim 33, comprising maintaining a pressure between about 100 and about 200 psi.37. The process of 22, comprising controlling temperature in said extruder in a feed section (L/D<9) to lees than 150° C. and then from said feed section to discharge between about 120 and about 240° C.38. (new) The process of claim 1, comprising controlling temperature in said extruder in a feed section (L/D<9) to less than 120° C. and then from said feed section to discharge between about 130 and about 230° C.39. The process of claim 22, wherein said length to diameter ratio is at least greater than 60.40. A process of preparing a liquid silicone rubber composition, comprising: introducing a filler, treating agent and silicone polymer into an extruder having a length to diameter ratio of at least greater than 50; and continuously compounding and devolatilizing said filler, treating agent and silicone polymer in said extruder while maintaining an elevated pressure in a section of said extruder to enhance reaction between said filler and said treating agent. 41. The process of claim 40, comprising maintaining a pressure between about 16 and about 400 psi.42. The process of claim 40, camping maintaining a pressure between about 40 to about 300 psi.43. The process of claim 40, comprising maintaining a pressure between about 100 and about 200 psi.44. The process of claim 40, wherein said extruder is a co-rotating, intermeshing double screw extruder.45. The process of claim 40, comprising densifying filler with an initial amount of silicone polymer prior to introduction of said filler into said extruder.46. The process of claim 40, further comprising dividing said liquid silicone rubber composition into a first stream and a second stream.47. The process of claim 46, wherein a platinum catalyst is added to said first stream to produce a component mixture A and a crosslinker is added to said second stream to produce a component mixture B.48. The process of claim 47, wherein said component mixture A and said component mixture B are injected into a mold where they are cured to produce a rubber part.49. The process of claim 40, wherein said filler is a raw, untreated silica.50. The process of claim 40, wherein said filler is a pretreated filler with treating agent.51. The process of claim 50, wherein said treating agent is a silanol-reacting treating agent.52. The process of claim 50, wherein said filler contains silanol groups and said treating agent comprises silanol-stopped polydimethylsiloxane, octamethylcyclotetrasiloxane (D4) or hexamethyldisilazane (HMDZ).53. The process of claim 40, comprising controlling temperature in said extruder in a feed section (L/D<9) to less than 150° C. and then from said feed section to discharge between about 120 and about 240° C.54. The process of claim 40, comprising controlling temperature in said extruder in a feed section (L/D<9) to less than 120° C. and then from said feed section to discharge between about 130 and about 230° C.55. The process of clam 40, wherein said length to diameter ratio is at least greater than 60.