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US 4,900,490 AGranted
Foam material
AssigneePackaging Industries Group, Inc.
InventorMatthew L. Kozma
Life of this patent
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Abstract
A foam material, particularly suitable for use as a midsole material for an athletic shoe, comprises polyethylene modified by an elastomer modifier and cross-linked, preferably using a peroxide cross-linking agent, to form a closed cell foam material which has superior strength properties, improved energy return and reduced sensitivity to temperature change.
Claims4
A method of making a foam material comprising:
- fusing a mixture comprising ethylene-propylene diene terpolymer, low density polyethylene and a chemically decomposing blowing agent in a dispersion mixer;
- sheeting the material;
- cooling the sheet material;
- press molding the sheet material in a hydraulic press;
- curing the material during the press molding step, and
- expanding the cured molded material immediately on opening the press to form a foam material having a density of about 7 to 10 lb/cu. ft. and tear resistance of about 18 to 22 lb/in.
3 more elements
A method of making a foam material comprising:
- blending polyethylene, ethylene propylene diene terpolymer elastomer modifier, blowing agent and crosslinking agent to form a resin blend;
- crosslinking said resin at increased temperature and pressure in a hydraulic press, and
- foaming said resin to form a thermosetting closed cell foam material,
- wherein said foam material has a compression deflection at 25% deflection greater than 20 lb./sq/in., a tensile strength greater than 175 lb./sq. in. and an elongation greater than 150%, providing improved energy return and reduced sensitivity of energy return to temperature change compared with elastomer alone.
1 more element
A method of making a foam material comprising:
- fusing a mixture comprising ethylene-propylene diene terpolymer, low density polyethylene and a chemically decomposing blowing agent in a dispersion mixer;
- sheeting the material;
- cooling the sheet material;
- press molding the sheet material in a hydraulic press;
- curing the material during the press molding step, and
- expanding the cured, molded material immediately on opening the press to form a foam material, wherein said foam material has a compression deflection at 25% deflection greater than 20 lb./sq/in., a tensile strength greater than 175 lb/sq. in. and an elongation greater than 150%, providing improved energy return and reduced sensitivity of energy return to temperature change compared with elastomer alone.
3 more elements
Dependencies are inferred from the claim text.