Foamed thermoplastic resin comprising a mixture of ionomer and polyolefin
AssigneeAsahi-Dow Limited
InventorsSeizaburo Watanabe, Eiji Hattori, Kanau Mori
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Abstract
Foamed thermoplastic mixture of ionomers and polyolefin polymers are produced by extruding the mix together with a volatile blowing agent at elevated temperature and pressure. The density of the foamed products is from of 15 to 45 Kg/m.sup.3 and they satisfy the requirements of extrusion foamability, compressive strength or rigidity, thermal resistance and adhesion properties.
Claims15
A thermoplastic foamed resin product characterized by low density, high thermal resistance, good adhesion properties and uniform cell size which comprises a mixture containing from 35% to 95% ionomer characterized by the presence of a monomer unit based on an unsaturated carboxylic acid and 5% to 65% polyolefin polymer or copolymer, based on the total weight of resin;
- the ethylene monomer unit and unsaturated carboxylic acid ester monomer unit values of the ionomer being from 50 to 97 mol% and up to 30 mol%;
- respectively, the neutrality value of the ionomer being up to 50%, the saponification value of the ionomer being at least 50%, and the melt index of the ionomer being from 0.1 to 50 g/10 min.;
- the melt index of the polyolefin being from 0.1 to 30 g/10 min.
A process for the production of a thermoplastic foamed resin product characterized by low density, high thermal resistance, good adhesion properties and uniform cell size which comprises a mixture containing 35% to 95% ionomer characterized by the presence of a monomer unit based on an unsaturated carboxylic acid and 5% to 65% polyolefin homopolymer or copolymer, based on the total weight of resin;
- ethylene monomer unit and unsaturated carboxylic acid ester monomer unit values of the ionomer being from 50 to 97 mol% and up to 30 mol%, respectively, the neutrality value of the ionomer being up to 50%, the saponification value of the ionomer being from 0.1 to 50 g/10 min.;
- the melt index of the polyolefin being from 0.1 to 30 g/10 min.:
- which process comprises the steps of:
- 1. mixing the ionomer with a volatile blowing agent and the polyolefin at a temperature of from 100.degree. C to 250.degree. C and a pressure of from 50 to 250 kg/cm.sup.2, weight ratio of the blowing agent to polyolefin being at least 5 parts to 100 parts, and
- 2. extruding the mixture at a temperature of from 60.degree. C to 150.degree. C and a pressure of 20 to 150 kg/cm.sup.2 into a region of reduced pressure thereby to cause volatilization of the blowing agent and foaming of the mixture.
Dependencies are inferred from the claim text.