Foams Made from Blends of Ethylene Styrene Interpolymers with Polyethylene,Polypropylene and Polystyrene

Abstract

INSITE** Technology from The Dow Chemical Company has enabled the production of ethylene-styrene Interpolymers (ESI) by copolymerization of ethylene and styrene monomers. The properties of interpolymers vary significantly with copolymer styrene content. Interpolymers with up to about 45 weight percent copolymer styrene are semicrystalline and exhibit good low temperature toughness. Interpolymers with greater than about 45 weight percent copolymer styrene are essentially amorphous and range from those that have low modulus and high elongation to those that have higher modulus with unique stress relaxation and dead fold properties. Interpolymers have both aromatic and aliphatic functionality. Hence, they are compatible with a variety of other thermoplastics. Interpolymers have been commercially launched under the trademark "INDEXt Interpolymers" and are classified as E-Series (up to about 45 weight percent styrene) or S-series (greater than about 45 weight percent styrene). This paper describes the properties of blends of interpolymers with low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP) and polystyrene (PS), as well as the novel and unique foams made by expanding some of these blends with physical blowing agents.

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References

1. U.S. Patent 5,703,187, "Pseudo-random Copolymers Formed by Use of Constrained Geometry Addition Polymerization Catalysts," F. J. Timmers , The Dow Chemical Company (December 30, 1997).

2. Karande, S. V. and Chaudhary, B. I. , "INSITE Technology Based Ethylene Styrene Interpolymers for Foams Applications," FOAMPLAS'98, Proceedings of Second Worldwide Conference on Foamed Thermoplastics Markets & Technology, May 19-20, 1998, New Jersey (pp. 1-8).

3. Chen, H. et al. , "Classification of Ethylene-Styrene Interpolymers Based on Comonomer Content," 1998, Journal of Applied Polymer Science, 70:109-119.

4. Chaudhary, B. I. and Barry, R. P. , "Extruded Non-crosslinked Foams Made From Ethylene-Styrene Interpolymers and Blends with Polyethylene," 1999, Journal of Cellular Plastics, 35, 531-549.

5. Chaudhary, B. I. and Barry, R. P. , "Extruded Noncrosslinked Foams Made From Ethylene-Styrene Interpolymers," Proceedings of FOAMS '99-First International Conference on Thermoplastic Foam Processing & Technology, October 19-20, 1999.

6. Chaudhary, B. I. and Johns, A. I. , "Solubilities of Nitrogen, Isobutane and Carbon Dioxide in Polyethylene," 1998, Journal of Cellular Plastics, 34:312-328.

7. Diehl, C. F. , Guest, M. J. , Chaudhary, B. I. , Cheung, Y. W. , Van Volkenburgh, W. R. and Walther, B. , "Blends of Ethylene/Styrene Interpolymers and Other Polymers: Benefits in Applications," ANTEC '99 Conference Proceedings, Volume II, May 2-6, 1999, New York (pp. 2149-2153).

8. PCT Int. Appl. WO 98/10015, "Blends of Alpha-Olefin/Vinylidene Aromatic Monomer or Hindered Aliphatic Vinylidene Monomer Interpolymers with Polyolefins and Adhesives, Fibers, Sheets, Films, and Moldings Containing The Same," C. P. Park et al., The Dow Chemical Company (March 12,1998).

9. U.S. Patent 5,993,707, "Enlarged Cell Size Foams Made from Blends of Alkenyl Aromatic Polymers and Alpha-Olefin Vinyl or Vinylidene Aromatic and/or Sterically Hindered Aliphatic or Cycloaliphatic Vinyl or Vinylidene Interpolymers," B. I. Chaudhary et al., The Dow Chemical Company (November 30, 1999).