Molding touch fastener elements

Abstract

A product comprising a base layer and a multiplicity of protruding hollow formations, the protruding formations unitarily formed with and extending upward from an upper surface of the base layer, the hollow formations and base layer formed of thermoplastic applied under pressure against a forming surface having forming cavities and the base layer having a back surface including interior surfaces of the hollow formations comprising a parting surface from which a second thermoplastic filling the hollow formations has been peeled.

1 . A product comprising: 
 a base layer and a multiplicity of protruding hollow formations, the protruding formations unitarily formed with and extending upward from an upper surface of the base layer, the hollow formations and base layer formed of thermoplastic applied under pressure against a forming surface having forming cavities and the base layer having a back surface including interior surfaces of the hollow formations comprising a parting surface from which a second thermoplastic filling the hollow formations has been peeled.    
   
   
       2 . The product of  claim 1  wherein the protruding formations are elements of fastener formations.  
   
   
       3 . The product of  claim 2  wherein the elements of fastener elements are loop engageable formations.  
   
   
       4 . The product of  claim 3  wherein the loop engageable formations are molded hooks.  
   
   
       5 . The product of  claim 2  wherein the elements of fastener formations are cylindrical hollow stems.  
   
   
       6 . The product of  claim 5  wherein the protruding formations are cylindrical hollow stems with post-formed distal ends.  
   
   
       7 . The product of  claim 1  further comprising a flowable substance filling the hollow formations.  
   
   
       8 . The product of  claim 7  further comprising a backing layer at least part of which forms a bond to a surface of the base layer so that the multiplicity of protruding formations cooperate with the backing layer to define a multiplicity of substantially enclosed chambers containing the flowable substance.  
   
   
       9 . The product of  claim 8  wherein the bond between the base and backing layer substantially seals individual chambers, movement of the flowable substance out of the individually sealed chambers through the base layer is limited by the backing layer.  
   
   
       10 . The product of  claim 8  wherein the bond between the base and backing layers substantially seals groups of the chambers, individual chambers within the groups of chambers remaining in flowable substance communication with each other while movement of the flowable substance out of the groups of chambers is limited by the backing layer.  
   
   
       11 . The product of  claim 8  wherein at least 10 percent of the protruding formations also defines an upper opening for dispensing the flowable substance.  
   
   
       12 . The product of  claim 11  wherein the opening is sized such that surface tension and viscosity substantially retain the flowable substance within the chambers until the protruding formations deform in response to applied pressure.  
   
   
       13 . The product of  claim 11  further comprising a sealing strip covering the upper openings, the sealing strip removable to dispense the flowable substance through the upper openings.  
   
   
       14 . The product of  claim 8  wherein the protruding formations each contain a discrete area whose structural strength is weaker than the structural strength of other areas of the protruding element.  
   
   
       15 . The product of  claim 8  wherein the flowable substance comprises a component that volatilizes when exposed to the atmosphere.  
   
   
       16 . The product of  claim 15  wherein the thermoplastic forming the hollow formations is chosen from thermoplastics whose permeability allows dispersion of the volatile component through the thermoplastic.  
   
   
       17 . The product of  claim 15  further comprising a disposable, absorbent undergarment wherein the base layer, hollow formations, flowable substance, and backing layer are attached to the disposable, absorbent undergarment.  
   
   
       18 . The product of  claim 15  further comprising a container liner portion wherein the base layer, hollow formations, flowable substance, and backing layer are attached to the container liner portion.  
   
   
       19 . The product of  claim 15  further comprising a sampler portion wherein the base layer, hollow formations, flowable substance, and backing layer are attached to the sampler portion with a sealing layer covering the first portion and limiting movement of the flowable substance out of the first portion, the sealing layer removable to dispense the flowable substance.  
   
   
       20 . The product of  claim 8  wherein the flowable substance is selected from a group including: a medicament appropriate for topical application; an antibiotic; an analgesic; components that reduce transmission of ultraviolet radiation; and components that repel insects.  
   
   
       21 . A method of forming a sheet-form product, the method comprising: 
 providing a forming surface having a multiplicity of inwardly extending forming cavities;    forming a multi-layer sheet in the interior of which is a parting surface defined by materials of limited compatibility, material of the sheet lying on each side of the parting surface having peelable tensile strength;    pressing the multi-layer sheet against the forming surface to cause the multi-layer sheet to substantially conform to and fill the cavities; and    peeling the multi-layer sheet apart at the parting surface, whereby material directly engaging the forming surface defines a sheet-form member having a multiplicity of hollow formations.    
   
   
       22 . The method of  claim 21  in which the forming cavities define at least stems for fastener elements.  
   
   
       23 . The method of  claim 22  wherein the forming cavities define cylindrical formations.  
   
   
       24 . The method of  claim 22  wherein the forming cavities define loop engageable formations.  
   
   
       25 . The method of  claim 24  wherein the loop engageable formations are molded hooks.  
   
   
       26 . The method of  claim 21  wherein forming a multi-layer sheet comprises continuously introducing a first molten thermoplastic and a second molten thermoplastic into a gap defined adjacent to the forming surface.  
   
   
       27 . The method of  claim 21  further comprising, forming a dispensing hole in the hollow formations.  
   
   
       28 . The method of  claim 27  wherein forming a dispensing hole comprises laser radiating the hollow formations to burn through the sheet-form member.  
   
   
       29 . The method of  claim 27  wherein forming a dispensing hole comprises mechanically piercing the hollow formations.  
   
   
       30 . The method of  claim 21  wherein mold pins extend into the forming cavities from a body of the forming surface.  
   
   
       31 . The method of  claim 21  further comprising, weakening a discrete area of the hollow formations.  
   
   
       32 . The method of  claim 31  wherein weakening comprises laser radiating the hollow formations for a period of time chosen to decrease the structural strength of a discrete area of the hollow formations without burning through the sheet-form member.  
   
   
       33 . The method of  claim 21  further comprising filling the hollow formations with a flowable substance.  
   
   
       34 . The method of  claim 33  further comprising, after filling, bonding a backing layer to the sheet-form member to form a multiplicity of substantially enclosed chambers.  
   
   
       35 . The method of  claim 34  wherein the flowable substance comprises a component that volatilizes when exposed to the atmosphere.  
   
   
       36 . The method of  claim 33  further comprising choosing the flowable substance from a group including: a medicament appropriate for topical application; an antibiotic; an analgesic; components that reduce transmission of ultraviolet radiation; and components that repel insects.  
   
   
       37 . A hook component of a hook and loop fastener system, the hook component comprising: 
 a field of hollow loop-engageable elements projecting from a base layer;    a flowable substance within the hollow elements; and    a dispensing feature enabling dispensing of the flowable substance in response to deformation of the loop-engageable elements.    
   
   
       38 . The hook component of  claim 37  wherein backing material and the hollow loop-engageable elements define cavities containing the flowable substance.  
   
   
       39 . The hook component of  claim 37  wherein the hollow loop-engageable elements comprise hooks having loop-engageable heads.  
   
   
       40 . The hook component of  claim 37  wherein the hollow loop-engageable elements dispense the flowable substance when deformed.  
   
   
       41 . The hook component of  claim 37  wherein the hollow loop-engageable elements are deformable in response to disengagement of the hook component from a mating fastener component.  
   
   
       42 . The hook component of  claim 41  wherein the hollow loop-engageable elements dispense the flowable substance when deformed.  
   
   
       43 . A method of forming a sheet form product, the method comprising: 
 forming a multi-layer sheet having a first layer forming a first broad surface of the multi-layer sheet;    pressing the multi-layer sheet against a forming surface with the first layer contacting the forming surface such that the multi-layer sheet substantially conforms to and fills a multiplicity of inwardly extending forming cavities in the forming surface;    removing the multi-layer sheet from the forming surface;    removing the first layer from remaining portions of the multi-layer sheet, the remaining portions of the multi-layer sheet defining a member having stems of fastener elements integrally molded with and extending from a sheet-form base.    
   
   
       44 . The method of  claim 43  wherein the first layer is interposed between the remaining portions of the multi-layer sheet and the forming surface when the multi-layer sheet is pressed against the forming surface.  
   
   
       45 . The method of  claim 44  wherein the remaining portions comprise additives.  
   
   
       46 . The method of  claim 45  wherein the additives comprise materials, such as titanium dioxide or calcium carbonate, that increase the rate of accumulation of contaminating material on the surfaces the resin and additives contact and the method further comprises sizing a thickness of the first layer to limit contact between the forming surface and the remaining portions.  
   
   
       47 . The method of  claim 45  wherein the additives comprise materials that increase abrasive characteristics of the remaining portions and the method further comprises sizing a thickness of the first layer to reduce wear on the forming surface from the remaining portions.  
   
   
       48 . The method of  claim 44  further comprises sizing a thickness of the first layer based on sizes of irregularities in the forming surface.  
   
   
       49 . The method of  claim 43  further comprising selecting materials for the first layer that have a first flexural modulus and materials for the remaining portions that have a second flexural modulus such that the second flexural modulus is greater than the first flexural modulus.  
   
   
       50 . The method of  claim 49  wherein the second flexural modulus is greater than 300,000 pounds per square inch.  
   
   
       51 . The method of  claim 50  wherein the second flexural modulus is greater than 500,000 pounds per square inch.  
   
   
       52 . The method of  claim 51  wherein the second flexural modulus is greater than 750,000 pounds per square inch.  
   
   
       53 . The method of  claim 49  wherein removing the multi-layer sheet from the forming surface comprises compressing the first layer between the forming surface and remaining portions.  
   
   
       54 . The method of  claim 49  further comprising forcing the remaining portions through the first layer.