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 system for preparing a liquid silicone rubber composition, comprising:a mixer to prepare a concentrate of filler and silicone polymer; a long extruder having an L/D ratio of at least greater than 50, connected to said mixer to receive said concentrate from said mixer and to compound and devolat

1. A system for preparing a liquid silicone rubber composition, comprising:a mixer to prepare a concentrate of filler and silicone polymer; a long extruder having an L/D ratio of at least greater than 50, connected to said mixer to receive said concentrate from said mixer and to compound and devolatilize said concentrate, a treating agent and silicone polymer into a liquid silicone rubber composition containing volatiles; a counter rotating double screw extruder to receive said liquid silicone rubber composition to cool, homogenize and further devolatilize said composition; and further comprising at least two divided lines respectively comprising at least a first liquid silicone rubber composition stream with added platinum catalyst and a second liquid silicone rubber composition stream with added crosslinker. 2. The system of claim 1, wherein said long extruder has an L/D ratio of greater than about 60.3. The system of claim 1, wherein said extruder comprises a feed section (L/D<9) with a controlled temperature of less than 150° C. and a discharge section with a controlled temperature between about 120° C. and about 240° C.4. The system of claim 1, wherein said extruder comprises a feed section (L/D<9) with a controlled temperature of less than 150° C. and a discharge section with a controlled temperature between about 130° C. and about 230° C.5. A system for preparing a liquid silicone rubber composition, comprising:a mixer to prepare a concentrate of filler and silicone polymer; a long extruder having an L/D ratio of greater than 70, connected to said mixer to receive said concentrate from said mixer and to compound and devolatilize said concentrate, a treating agent and silicone polymer into a liquid silicone rubber composition containing volatiles; a cooler to receive said liquid silicone rubber composition to cool, homogenize and further devolatilize said composition; and further comprising at least two divided lines respectively comprising at least a first liquid silicone rubber composition stream with added platinum catalyst and a second liquid silicone rubber composition stream with added crosslinker. 6. The system of claim 5, wherein said extruder is a co-rotating, intermeshing double screw extruder.7. The system of claim 5, wherein said cooler comprises a counter rotating double screw extruder.8. The system of claim 5, wherein said liquid silicone rubber composition is cooled, homogenized and further devolatilized in said cooler.9. The system of claim 5, wherein said filler is a raw, untreated silica.10. The system of claim 5, wherein said filler is a pretreated filler with treating agent.11. The system of claim 10, wherein said treating agent is a silanol-reacting treating agent.12. The system of claim 10, wherein said filler contains silanol groups and said treating agent comprises silanol-stopped polydimethylsiloxane, octamethylcyclotetrasiloxane (D4) or hexamethyldisilazane (HMDZ).13. The system of claim 5, wherein said extruder comprises a feed section (L/D<9) with a controlled temperature of less than 150° C. and a discharge section with a controlled temperature between about 120° C. and about 240° C.14. The system of claim 5, said extruded comprises a feed section (L/D<9) with a controlled temperature of less than 150° C. and a discharge section with a controlled temperature between about 130° C. and about 230° C.15. The system of claim 5, wherein said silicone polymer comprises a vinyl-terminated polydimethylsiloxane represented by recurring units of Formula I: wherein, R1 independently at each occurrence represents C1-4 alkyl, or C2-4 alkylene; R2 independently at each occurrence represents C1-4 alkyl, C1-C4 haloalkyl or C2-4 alkylene; R3 independently at each occurrence represents H, C1-10 alkyl, C2-4 alkylene, C4-6 cycloalkyl, OH or C1-C4 haloalkyl; and n is a value of about 100 to less than 1000.16. The system of claim 15, wherein R1 independently at each occurrence represents, CH3 or CH?CH2; R2 independently at each occurrence represents, CH3, CH?CH2 or CH2CH2CF3; and R3 independently at each occurrence represents CH3, CH?CH2, OH or CH2CH2CF3.