Elastomeric formulations useful in films and sheets
An elastomeric composition, and method of making the same, useful for forming thin films and sheets, comprising 55-60% hydrogenated SEEPS having a number average molecular weight of 90,000 to 100,000, 7-12% polystyrene, 15-30% oil, and 5 to 20% of an aliphatic hydrogenated hydrocarbon resin.
1. An elastomeric composition, comprising: 55-60% by weight hydrogenated isoprene-1,3-butadiene (SEEPS) block copolymer having a number average molecular weight of about 90,000 to 100,000 and a mass ratio of isoprene to 1,3-butadiene in the block copolymer of from 46/54 to 44/56;
7-12% weight polystyrene;
15-20% by weight mineral oil; and
5-20% by weight of an aliphatic hydrogenated hydrocarbon resin;
wherein the % by weight values are relative to a total weight of the composition.
2. The elastomeric composition of claim 1 wherein a glass transition temperature (T g ° C.) of the aliphatic hydrogenated hydrocarbon resin is 65-75° C. and a number average molecular weight of the aliphatic hydrogenated hydrocarbon resin is about 650 to 800.
3. The elastomeric composition of claim 2 wherein the mass ratio of isoprene to 1,3-butadiene in the block copolymer is 45/55.
4. The elastomeric composition of claim 2 , wherein
the content of the mineral oil is from 16 to 20% by weight,
the content of polystyrene is from 8 to 10% by weight, and
the content of the aliphatic hydrogenated hydrocarbon resin is 10 to 16% by weight.
5. An elastomeric composition comprising:
55-60% by weight hydrogenated isoprene-1,3-butadiene (SEEPS) block copolymer having a number average molecular weight of about 90,000 to 100,000;
7-12% by weight polystyrene;
15-30% by weight mineral oil;
wherein a mass ratio of isoprene to 1,3-butadiene in the block copolymer is from 46/54 to 44/56, and
wherein the % by weight values are relative to a total weight of the composition.
6. The elastomeric composition of claim 5 , wherein the mass ratio of isoprene to 1,3-butadiene in the block copolymer is 45/55.
7. A method to prepare an eleastomeric film comprising the composition of claim 1 , the method comprising:
mixing the mineral oil and SEEPS block copolymer;
blending the polystyrene and aliphatic hydrogenated hydrocarbon resin into the mineral oil SEEPS mixture to obtain an extrusion feed;
supplying the extrusion feed to an extruder; and
extruding the extrusion feed to obtain the elastomeric film.
8. The method to prepare an elastomeric film of claim 7 , wherein a glass transition temperature (T g ° C.) of the aliphatic hydrogenated hydrocarbon resin is 65-75° C. and a number average molecular weight of the aliphatic hydrogenated hydrocarbon resin is about 650 to 800.
9. An elastomeric film obtained according to the method of claim 7 .
10. The elastomeric film of claim 9 , wherein a thickness on the film is from 2 to 10 mils.
11. An elastomeric sheet comprising the composition of claim 1 , wherein a thickness of the sheet is from 10 to 30 mils.
12. A method to prepare an eleastomeric film comprising the composition of claim 5 , the method comprising:
mixing the mineral oil and SEEPS block copolymer;
blending the polystyrene into the mineral oil SEEPS mixture to obtain an extrusion feed;
supplying the extrusion feed to an extruder; and
extruding the extrusion feed to obtain the elastomeric film.
13. An elastomeric film obtained according to the method of claim 12 .
14. The elastomeric film of claim 13 , wherein a thickness on the film is from 2 to 10 mils.
15. An elastomeric sheet comprising the composition of claim 5 , wherein a thickness of the sheet is from 10 to 30 mils.