US 6,299,817 B1Granted

Method for seamless construction of molded elastomer products

OwnerKevin G. Parkinsoninventor

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Abstract

A process which allows elastomeric materials of different colors, durometers and/or other material characteristics to chemically bond to one another so as to eliminate any possibility of delamination. Latex-based liquid elastomer solutions having different material characteristics are applied sequentially to a heated mold to form a series of layers making up the article, with rapid partial curing taking place between each application; the partial curing forms a skin coat over each layer which prevents intermixing of the different solutions, but which still permits a chemical bond to form during full curing of the materials. The process applies equally to dip (immersion) molded and flat molded goods. An example of the invention as it relates to flat-molded goods is an athletic shoe sole, and an example as it relates to dip-molded goods is a resilient, one piece watersports boot which can be fitted over a human foot without a zipper.

Claims19

Dependent claims

A method for forming a one-piece elastomeric article, said method comprising the steps of:

providing a mold member having a mold area, said mold member being formed of thin, heat-conductive metal material having a low heat capacity in said mold area, said mold area further having a dull matte finish for enhanced absorption of infrared energy and a coating of polytetrafluorethylene formed over said matte finish for accelerating thermal absorption therefrom;
heating said mold member to a predetermined elevated temperature by placing said mold member in an infrared oven so that infrared energy is absorbed by said mold area having said dull matte finish;
applying a first liquid elastomer to said heated mold member so that said mold area is rapidly heat-quenched by transfer of heat into said first liquid elastomer through said matte finish and said polytetrafluorethylene coating so that said liquid elastomer gels on said mold member to form a first elastomer layer having a first material characteristic;
partially curing said first elastomer layer on said mold member so that a thin skin layer forms over an outer surface of said layer;
applying a second liquid elastomer to said mold member over at least a portion of said first elastomer layer thereon, so that said second liquid elastomer gels to form a second elastomer layer on said first elastomer layer while said skin coat prevents intermixing of said first and second liquid elastomers;
and
at least partially curing said second elastomer layer on said first elastomer layer so as to form a permanent chemical bond which prevents delamination of said first and second layers;
whereby said thin, heat conductive metal material, said dull matte finish and said polytetrafluoroethylene coating cooperate to provide rapid heating of said mold area by said infrared oven, and rapid quenching of said mold area by said first elastomer layer so as to avoid degradation of said material characteristic thereof.

5 more elements

A method for forming a one-piece elastomeric article having elastomer layers of different colors, said method comprising the steps of:

providing a mold member having a mold area, said mold member being formed of thin aluminum alloy material having a low heat capacity in said mold area, said mold area further having a sand-blasted matte finish for enhanced absorption of infrared energy and a coating of polytetrafluoroethylene formed over said matte finish for accelerating thermal absorption therefrom;
heating said mold member to a predetermined temperature by placing said mold member in an infrared oven so that infrared energy is absorbed by said mold area having said matte finish;
applying a first liquid latex-based plastisol to said heated mold member so that said mold area is rapidly heat-quenched by transfer of heat into said first liquid elastomer through said matte finish and said polytetrafluorethylene coating so that said liquid elastomer gels on said mold member form a first elastomer layer having a first color;
partially curing said first elastomer layer on said mold member so that a thin skin layer forms over an outer surface of said first elastomer layer;
applying a second liquid latex based plastisol to said mold member over at least a portion of said first elastomer layer thereon, so that said second liquid latex-based plastisol gels to form a second elastomer layer having a second color while said skin coat prevents intermixing of said first and second liquid plastisols and;
at least partially curing said second elastomer layer so as to form a permanent chemical bond which prevents delamination of said first and second layers;
whereby said thin, heat conductive metal material, said sand-blasted matte finish and said polytetrafluoroethylene coating cooperate to provide rapid heating of said mold area by said infrared oven, and rapid heat-quenching of said mold area by said first elastomer layer so as to avoid degradation of said color thereof.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/001,334Filed 30 Dec 1997 · continuation in part
Priority: 16 Oct 1990
Granted: 9 Oct 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

A43B 3/02
Footwear characterised by the shape or the use: boots covering the lower leg
A43B 1/10
Footwear characterised by the material: made of rubber
A43B 5/08
Footwear for sporting purposes: bathing shoes ; Aquatic sports shoes
A43B 7/12
Footwear with health or hygienic arrangements: special watertight footwear

Family

Application07/598,156Parent of this continuation-in-part · filed 16 Oct 1990
Application07/667,882Parent of this continuation-in-part · filed 12 Mar 1991
Application07/878,199Parent of this continuation · filed 4 May 1992
Application08/222,331Parent of this continuation · filed 4 Apr 1994
Application08/367,673Parent of this continuation · filed 30 Dec 1994
Application08/706,444Parent of this continuation-in-part · filed 30 Aug 1996
Application08/706,444Parent of this continuation
Application07/878,199Parent of this continuation-in-part
US 6,299,817 B1This patent

From the US filing history. Foreign family members aren’t listed.