Serrated screens for forming apertured three-dimensional sheet materials
OwnerHugh Joseph O'Donnell, Yann-Per Leeinventors
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Abstract
The present invention provides a forming structure comprising a screen having a plurality of apertures. The apertures each have a periphery, and each of the apertures has at least one protrusion extending inwardly from the periphery. The protrusions preferably extend inwardly to at least one apex, which may be sharp or have a finite radius. The forming structures may be utilized in a multi-phase forming process to form three-dimensional, macroscopically-expanded apertured film materials.
Claims20
A forming structure comprising a screen having a plurality of apertures, said apertures each having a periphery, each of said apertures having at least one protrusion extending inwardly from said periphery.
A process for forming a three-dimensional, macroscopically-expanded sheet material from a web of polymeric film material, said process comprising the steps of:
- (a) feeding said web onto a first forming structure having opposed surfaces such that a first surface of said web is in contact with said forming structure, said first forming structure exhibiting a multiplicity of microapertures which place the opposed surfaces of said first forming structure in fluid communication with one another;
- (b) applying a fluid pressure differential across the thickness of said web, said fluid pressure differential being sufficiently great to cause said web to rupture in those areas coinciding with said microapertures in said first forming structure and to conform with said first forming structure;
- (c) feeding said web onto a second forming structure having opposed surfaces, said second forming structure exhibiting a multiplicity of macroapertures which place the opposed surfaces of said second forming structure in fluid communication with one another, said macroapertures each having a periphery, said macroapertures each having at least one protrusion extending inwardly from said periphery;
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- (d) applying a fluid pressure differential across the thickness of said web, said fluid pressure differential being sufficiently great to cause said web to rupture in those areas coinciding with said macroapertures in said second forming structure and to conform with said second forming structure.
A process for forming a three-dimensional, macroscopically-expanded sheet material from a web of polymeric film material, said process comprising the steps of:
- (a) feeding said web onto a forming structure having opposed surfaces such that a first surface of said web is in contact with said forming structure, said forming structure exhibiting a multiplicity of apertures which place the opposed surfaces of said forming structure in fluid communication with one another, said apertures each having a periphery, said apertures each having at least one protrusion extending inwardly from said periphery;
- (b) applying a fluid pressure differential across the thickness of said web, said fluid pressure differential being sufficiently great to cause said web to rupture in those areas coinciding with said apertures in said forming structure and to conform with said forming structure.
Dependencies are inferred from the claim text.