Method of making objects having an elastomeric outer wall and a synthetic foam core

Claim 1

A method of making in a mould cavity objects having an outer wall from a micro-cellular or non-cellular elastomer and a core comprising a synthetic foam, wherein use is made of a mould comprising at least two mutually movable mould parts, which can be brought into an open and closed position with respect to each other, said parts having edges with contacting sides adjacent said mould cavity which are in substantially hermetically closed contact with each other in said closed position, the improvement comprising: applying, in a first step, a first layer of said elastomer onto a first mould part of said at least two mutually movable mould parts and a second layer of said elastomer onto a second mould part of said mutually movable mould parts, said elastomer layers also being applied onto said contacting sides of said edges of said first and second mould parts while said at least two mutually movable mould parts are in said open position; bringing, in a second step, the mould parts into said closed position while said elastomer is still substantially liquid so as to press at least a part of said elastomer layers located on said contacting sides of said edges away in the direction of said mould cavity, and to bring said contacting sides of said edges of said first and second mould parts into a hermetically closed state against each other, thereby connecting said elastomer layers such that a substantially invisible dividing joint is obtained on a side of said elastomer layers facing said mould parts and a thickening serving as a reinforcement is formed on a side of said elastomer layers facing said mould cavity, and injecting into a space defined by said elastomer layers a second reaction mixture which forms a synthetic foam; and demoulding, in a third step, after said synthetic foam has been cured substantially completely and forms a whole with said elastomer layers, a moulded object.

Claim 2

A method of making in a mould cavity objects having an outer wall from a micro-cellular or non-cellular elastomer and a core comprising a synthetic foam, wherein use is made of a mould comprising at least two mutually movable mould parts, which can be brought into an open and closed position with respect to each other, said parts having edges with contacting sides adjacent said mould cavity which are in substantially hermetically closed contact with each other in said closed position, the improvement comprising: applying, in a first step, a first layer of said elastomer onto a first mould part of said at least two mutually movable mould parts and a second layer of said elastomer onto a second mould part of said mutually movable mould parts, said elastomer layers also being applied onto said contacting sides of said edges of said first and second mould parts while said at least two mutually movable mould parts are in said open position; bringing, in a second step, the mould parts into said closed position while said elastomer is still substantially liquid so as to press at least a part of said elastomer layers located on said contacting sides of said edges away in the direction of said mould cavity, and to bring said contacting sides of said edges of said first and second mould parts into a hermetically closed state against each other, thereby connecting said elastomer layers such that a substantially invisible dividing joint is obtained on a side of said elastomer layers facing said mould parts and a thickening serving as a reinforcement is formed on a side of said elastomer layers facing said mould cavity, and injecting into a space defined by said elastomer layers a second reaction mixture which forms a synthetic foam; and demoulding, in a third step, after said synthetic foam has been cured substantially completely and forms a whole with said elastomer layers, a moulded object.