摘要:
Method and apparatus for constructing a three-dimensional film forming structure for imparting a uniformly apertured three-dimensional pattern to a heated plastic material subjected to a fluid pressure differential while in contact with said forming structure. In a preferred embodiment, said forming structure is created by forming a substantially continuous pattern of apertures in a multiplicity of planar sheets, at least a portion of said sheets having aperture patterns which are concentrically aligned but dissimilar in size to one another. The sheets having said concentrically aligned aperture patterns are thereafter superposed upon one another so as to form a stack exhibiting a three-dimensional continuum of capillary networks. A sufficient number of laminae are employed to ensure that said networks are of greater overall length than the maximum depth to which the plastic film being processed thereon is drawn when subjected to said fluid pressure differential. Said capillary networks exhibit a cross sectional area which reaches a minimum intermediate the uppermost and lowermost surfaces of the stack and thereafter increases in the direction of the lowermost surface of the stack to increase fluid permeability. The superposed sheets are bonded to one another at contact points while in the stacked configuration to form an integral laminate structure. The laminate forming structure is preferably caused to assume a tubular shape and its opposing free edges are secured to one another without disrupting the three-dimensional continuum of capillary networks along its periphery, thereby facilitating continuous plastic web processing against its outermost surface. The tubular laminate forming structure is preferably supported on a cylindrical drum by a multiplicity of radially oriented support members having lands which contact the innermost surface of the tubular member, but which are of ' insufficient cross-section to obstruct fluid flow through the capillary networks. Plastic material to be debossed and uniformly apertured may be extruded directly onto the surface of the forming structure while in a molten state or continuously fed in the form of film from a roll into contacting relation with the tubular laminate structure. The plastic material is subjected to a fluid pressure differential on said forming structure while at a temperature above its softening point. The overall thickness and configuration of the permeable laminate structure permits uniform application of fluid pressure, usually vacuum, to the lowermost surface of the plastic film, while preventing contact between the film and the support members. As a result, the heated film is uniformly debossed and apertured in conformance with the surface of the forming structure. The uniformly debossed and apertured film is cooled below its softening temperature and thereafter removed from the forming structure.
摘要:
A microbubbled, substantially fluid-impervious polymeric web exhibiting substantially the same consumer preferred soft and cloth-like tactile impression and low noise generation levels heretofore only achievable in microapertured, and hence substantially fluid pervious, polymeric webs. In a particularly preferred embodiment, the present invention pertains to a microbubbled polymeric web exhibiting a fine-scale pattern of discrete mushroom-shaped surface aberrations, each of said surface aberrations having its amplitude oriented substantially perpendicular to the surface in which the surface aberration originates. However, unlike microapertured webs which are fluid pervious, at least one tiny, continuous membrane bubble, i.e., a microbubble, is provided substantially coincidental with the maximum amplitude of each surface aberration. Thus, the microbubbled web is substantially fluid-impervious. In addition, such a web employing the fine-scale pattern of microbubbled surface aberrations does not exhibit the "rattling" or "rustling" noises typically exhibited by prior art fluid-impervious polymeric webs when subjected to movement. As a result, webs of the present invention have particular utility in environments such as substantially fluid-impervious backsheets for disposable infant diapers and adult incontinent diapers. The microbubbled webs are preferably formed by supporting a web of polymeric film on a moving forming structure and applying a liquid to the exposed surface of the web to permanently deform the web in the image of the forming structure. This is preferably accomplished by subjecting the exposed surface of the web to either a high pressure liquid stream or to hydraulic pressure imposed by a liquid laden deformable roll. The microbubbled webs can be produced either in "planar" or "macroscopically expanded" form.
摘要:
Method and apparatus for uniformly macroscopically expanding and, if desired, aperturing a plastic web. This is preferably accomplished by supporting the plastic web on a moving three-dimensional forming structure which is supported in a fluid pressure differential zone by a stationary support member. By providing a relationship between the size and pattern of the apertures in the stationary support member and the size and pattern of the apertures in the three-dimensional forming structure, substantially all of the apertures present in the forming structure are unobstructed by the stationary support member at some point during the forming structure's traverse of the fluid pressure differential zone. Thus the resultant plastic web is uniformly debossed and, if desired, apertured in the pattern of the three-dimensional forming structure.
摘要:
Method and apparatus for constructing a three-dimensional film forming structure for imparting a uniformly apertured three-dimensional pattern to a heated plastic material subjected to a fluid pressure differential while in contact with said forming structure. In a preferred embodiment, said forming structure is created by forming a substantially continuous pattern of apertures in a multiplicity of planar sheets, at least a portion of said sheets having aperture patterns which are concentrically aligned but dissimilar in size to one another. The sheets having said concentrically aligned aperture patterns are thereafter superposed upon one another so as to form a stack exhibiting a three-dimensional continuum of capillary networks. A sufficient number of laminae are employed to ensure that said networks are of greater overall length than the maximum depth to which the plastic film being processed thereon is drawn when subjected to said fluid pressure differential. Said capillary networks exhibit a cross sectional area which reaches a minimum intermediate the uppermost and lowermost surfaces of the stack and thereafter increases in the direction of the lowermost surface of the stack to increase fluid permeability. The superposed sheets are bonded to one another at contact points while in the stacked configuration to form an integral laminate structure. The laminate forming structure is preferably caused to assume a tubular shape and its opposing free edges are secured to one another without disrupting the three-dimensional continuum of capillary networks along its periphery, thereby facilitating continuous plastic web processing against its outermost surface. The tubular laminate forming structure is preferably supported on a cylindrical drum by a multiplicity of radially oriented support members having lands which contact the innermost surface of the tubular member, but which are of ' insufficient cross-section to obstruct fluid flow through the capillary networks. Plastic material to be debossed and uniformly apertured may be extruded directly onto the surface of the forming structure while in a molten state or continuously fed in the form of film from a roll into contacting relation with the tubular laminate structure. The plastic material is subjected to a fluid pressure differential on said forming structure while at a temperature above its softening point. The overall thickness and configuration of the permeable laminate structure permits uniform application of fluid pressure, usually vacuum, to the lowermost surface of the plastic film, while preventing contact between the film and the support members. As a result, the heated film is uniformly debossed and apertured in conformance with the surface of the forming structure. The uniformly debossed and apertured film is cooled below its softening temperature and thereafter removed from the forming structure.
摘要:
Method and apparatus for uniformly macroscopically expanding and, if desired, aperturing a plastic web. This is preferably accomplished by supporting the plastic web on a moving three-dimensional forming structure which is supported in a fluid pressure differential zone by a stationary support member. By providing a relationship between the size and pattern of the apertures in the stationary support member and the size and pattern of the apertures in the three-dimensional forming structure, substantially all of the apertures present in the forming structure are unobstructed by the stationary support member at some point during the forming structure's traverse of the fluid pressure differential zone. Thus the resultant plastic web is uniformly debossed and, if desired, apertured in the pattern of the three-dimensional forming structure.