Claims
- 1. A rubber modified monovinylidene aromatic polymer having a bimodal particle size distribution comprising:a) rubber particles of a star or branched low viscosity rubber, having a solution viscosity (5 percent in styrene at 20° C.) of from 20 to 120 centipoise and a Mooney viscosity (ML+1 at 100° C.) of from 30 to 80 centipoise, a volume average particle size of from 0.1 to 2μ, an average monovinylidene aromatic polymer to rubber occlusion content of from 3.1 to 6, and a cellular or core shell morphology or mixture thereof, and b) rubber particles of a star or branched low viscosity rubber, linear diene rubber or block copolymer rubber having a solution viscosity (5 per cent in styrene at 20° C.) of from 20 to 120 centipoise and a Mooney viscosity (ML+1 at 100° C.) of from 30 to 80 centipoise, a volume average particle size of from 0.5 to 10μ, characterized in that the rubber particles of b) are more dense than the particles of a), having an average monovinylidene aromatic polymer to rubber occlusion content of 0.5 to 3, wherein the particles of a) are from 50 to 99 wt. % of the total diene rubber content.
- 2. The composition of claim 1 wherein the rubber of a) is a homopolymer of butadiene.
- 3. The composition of claim 1 wherein the rubber of b) is a homopolymer of butadiene.
- 4. The composition of claim 1 wherein the polymer is a HIPS polymer and the rubber particles of a) are from 0.2 to 1.5μ.
- 5. The composition of claim 4 wherein the rubber particles of a) are from 0.2 to 1.4μ.
- 6. The composition of claim 5 wherein the rubber particles of a) are from 0.3 to 1.4μ.
- 7. The composition of claim 1 wherein the polymer is a HIPS polymer and the rubber particles of b) are from 1.0 to 8μ.
- 8. The composition of claim 7 wherein the rubber particles of b) are from 1.2 to 7μ.
- 9. The composition of claim 8 wherein the rubber particles of b) are from 1.3 to 6μ.
- 10. The composition of claim 1 wherein the polymer is an ABS polymer and the rubber particles of a) are from 0.2 to 1μ.
- 11. The composition of claim 10 wherein the rubber particles of a) are from 0.3 to 1μ.
- 12. The composition of claim 11 wherein the rubber particles of a) are from 0.4 to 0.9μ.
- 13. The composition of claim 12 wherein the rubber particles of a) are from 0.4 to 0.8μ.
- 14. The composition of claim 1 wherein the polymer is an ABS polymer and the rubber particles of b) are from 0.8 to 10μ.
- 15. The composition of claim 14 wherein the rubber particles of b) are from 0.9 to 6μ.
- 16. The composition of claim 15 wherein the rubber particles of b) are from 0.9 to 4μ.
- 17. The composition of claim 16 wherein the rubber particles of b) are from 1 to 4μ.
- 18. The composition of claim 1 wherein the rubber particles of a) have a core shell morphology.
- 19. The composition of claim 1 wherein the rubber particles of a) have a cellular morphology.
- 20. The composition of claim 1 wherein the rubber particles of a) have a mixture of core shell and cellular morphology.
- 21. A process for producing the polymer of claim 1 comprising:A) polymerizing a polymerization mixture (1) comprising vinyl aromatic monomer and dissolved star or branched low viscosity rubber into a first reactor, such that rubber particles having a volume average particle size of from 0.1 to 2μ and a cellular or core shell morphology or mixture thereof and an occluded monovinylidene aromatic polymer to rubber content of 3.1 to 6, are produced within a partially polymerized polymer matrix, B) mixing the product of A) with a polymerization mixture (2) comprising vinyl aromatic monomer and dissolved star or branched low viscosity rubber, linear diene rubber or block copolymer rubber, under conditions such that the resultant mixture has a solids content of at least 4 times the total rubber content of the mixture, and large dense particles are produced having a volume average particle size of from 0.5 to 10μ and an average monovinylidene aromatic polymer to rubber occlusion content of from 0.5 to 3, and C) further polymerizing the product of B) to produce a rubber modified monovinylidene aromatic polymer having a bimodal particle distribution.
- 22. The process of claim 21 wherein polymerization mixture (1) further comprises an initiator.
- 23. The process of claim 22 wherein the initiator is selected from the group consisting of tertiary butyl peroctoate, tertiary butyl perbenzoate and bis(ditertiary butyl peroxy) cyclohexamoate.
- 24. The process of claim 21 wherein polymerization mixture (1) further comprises a chain transfer agent.
- 25. The process of claim 24 wherein the chain transfer agent is n-dodecyl mercaptan.
Parent Case Info
This application claims the benefit of provisional application No. 60/055,507 filed on Aug. 13, 1997.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/US98/16500 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO99/09080 |
2/25/1999 |
WO |
A |
Foreign Referenced Citations (2)
Number |
Date |
Country |
0277687 |
Aug 1988 |
EP |
0418042 |
Mar 1991 |
EP |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/055507 |
Aug 1997 |
US |