Method of thermally processing elastomeric compositions and elastomeric compositions with improved processability
View Patent ↗The present invention provides an improved elastomeric composition that includes from about 0.01 to about 0.5 weight percent of a polyorganosiloxane or a combination of polyorganosiloxanes.
1. A melt extrudable composition comprising:
one or more elastomeric styrenic block copolymers, wherein the styrenic block copolymers include styrene-ethylene/propylene-styrene, styrene-ethylene/butylene-styrene, styrene-ethylene/propylene-styrene-ethylene/propylene, styrene-ethylene/butylene-styrene-ethylene/butylene, or combinations thereof, wherein the elastomeric polymers constitute about 50 wt. % or more of the composition; and
one or more polyorganosiloxanes having the following formula:
wherein,
R is an alkyl radical;
R 1 is a monovalent organic radical comprising an ethylene oxide group, vicinal epoxy group, or amino group; and
x and y are independently selected from the group consisting of positive integers.
2. The melt extrudable composition of claim 1 , wherein the styrenic copolymers are selected from the group consisting of styrene-ethylene/propylene-styrene block copolymers, styrene-ethylene/butylene-styrene block copolymers, and combinations thereof.
3. The melt extrudable composition of claim 1 , wherein the styrenic copolymers are selected from the group consisting of styrene-ethylene/propylene-styrene-ethylene/propylene block copolymers, styrene-ethylene/butylene-styrene-ethylene/butylene block copolymers, and combinations thereof.
4. The melt extrudable composition of claim 1 , wherein the polyorganosiloxanes comprise from about 0.01 to about 0.5 wt. % of the composition.
5. The melt extrudable composition of claim 1 , wherein the polyorganosiloxanes comprise from about 0.01 to about 0.2 wt. % of the composition.
6. The melt extrudable composition of claim 1 , wherein the polyorganosiloxanes comprise from about 0.01 to about 0.1 wt. % of the composition.
7. The melt extrudable composition of claim 1 , wherein the elastomeric polymers comprise greater than about 75 wt. % of the composition.
8. The melt extrudable composition of claim 1 , wherein the extrusion temperature of the composition is less than the extrusion temperature that would otherwise be required without the polyorganosiloxanes.
9. The melt extrudable composition of claim 1 , where the composition further comprises one or more titanates, zirconates, or a mixture thereof.
10. The melt extrudable composition of claim 1 , wherein the composition comprises one or more titanates, zirconates, or a mixture thereof, in an amount from about 0.01 to about 3 wt. %.
11. The melt extrudable composition of claim 1 , further comprising one or more polyolefins.
12. Continuous filaments comprising the melt extrudable composition of claim 1 .
13. A laminate comprising the continuous filaments of claim 12 and a nonwoven web.
14. The laminate of claim 13 , wherein the nonwoven web is a spunbond web.
15. A method for forming a melt extrudate, the method comprising extruding a composition through a die of an extruder, the composition comprising one or more elastomeric styrenic block copolymers, wherein the styrenic block copolymers include styrene-ethylene/propylene-styrene, styrene-ethylene/butylene-styrene, styrene-ethylene/propylene-styrene-ethylene/propylene, styrene-ethylene/butylene-styrene-ethylene/butylene, or combinations thereof, wherein the elastomeric polymers constitute about 50 wt. % or more of the composition, the composition further comprising one or more polyorganosiloxanes having the following formula:
wherein,
R is an alkyl radical;
R 1 is a monovalent organic radical comprising an ethylene oxide group, vicinal epoxy group, or amino group; and
x and y are independently selected from the group consisting of positive integers.
16. The method of claim 15 , wherein one or more of the elastomeric polymers has a styrenic endblock.
17. The method of claim 15 , wherein the styrenic triblock copolymers are selected from the group consisting of styrene-ethylene/propylene-styrene block copolymers, styrene-ethylene/butylene-styrene block copolymers, and combinations thereof.
18. The method of claim 15 , wherein the styrenic copolymers are selected from the group consisting of styrene-ethylene/propylene-styrene-ethylene/propylene block copolymers, styrene-ethylene/butylene-styrene-ethylene/butylene block copolymers, and combinations thereof.
19. The method of claim 15 , wherein the polyorganosiloxanes comprise from about 0.01 to about 0.5 wt. % of the composition.
20. The method of claim 15 , wherein extrusion occurs at a temperature that is less than the extrusion temperature that would otherwise be required without the polyorganosiloxanes.
21. The method of claim 15 , where the composition further comprises one or more titanates, zirconates, or a mixture thereof.
22. The method of claim 15 , wherein the composition is extruded from the die onto a roller positioned at a canted angle relative to the die.
23. The method of claim 15 , wherein the extruded composition is stretched using a series of vertically disposed rollers.
24. The method of claim 15 , wherein the composition is extruded at a temperature of from about 260° F. to about 460° F.
25. The method of claim 15 , wherein the extruded composition is in the form of continuous filaments.
26. The method of claim 25 , further comprising laminating the continuous filaments to one or more sheet materials.
27. The method of claim 26 , wherein the sheet materials are nonwoven webs.
28. The method of claim 27 , wherein the continuous filaments are laminated to one or more spunbond webs.