Polyolefin film exhibiting heat resistivity, low hexane extractives and controlled modulus

US5792534A · kind A · utility

Assignee

• THE DOW CHEMICAL COMPANY · US

Inventors

• Jacquelyn A. Degroot · Sugar Land, US
• Lonnie G. Hazlitt · Lake Jackson, US
• Pradeep Jain · Lake Jackson, US
• Seema V. Karande · Lake Jackson, US
• Laura K. Mergenhagen · Lake Jackson, US
• Dan G. Moldovan · Angleton, US
• Kenneth Stewart · Lake Jackson, US
• Nicole F. Whiteman · Angleton, US

Key dates

• Filing date: Jun 7, 1995
• Grant date: Aug 11, 1998
• Expiry date: Jun 7, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31913
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The subject invention provides a polymer mixture having high heat resistivity, low hexane extractive and controllably lower or higher modulus. The mixture is comprised of at least one first substantially linear ethylene polymer, Component (A), and at least one second ethylene polymer which is a homogeneously branched polymer, heterogeneously branched linear polymer or a non-short chain branched linear polymer. When fabricated into film, the mixture is characterized by a heat seal initiation temperature which is substantially lower than its Vicat softening point as well as a high ultimate hot tack strength. When fabricated as a molded article, the mixture is characterized by high microwave warp distortion while maintaining a lower modulus. The polymer mixture is particularly well-suited for use in multilayer film structures as a sealant layer for such applications as cook-in packages, hot-fill packages, and barrier shrink films. In molding applications, the mixture is well-suited as freezer-to-microwave food storage containers and lids which maintain good flexibility at low temperature to allow easy openability of such containers.