Active fasteners

Abstract

Fastener products, for example for use in hook and loop fasteners are provided. The fastener products include a sheet form backing, and, extending from the backing, a plurality of fastener elements that include a shape memory polymer. Method of making and using such fastener products are also provided.

What is claimed is:  
     
         1 . A fastener product comprising 
 a sheet form backing; and    extending from the backing, a plurality of fastener elements comprising a shape memory polymer.    
     
     
         2 . The fastener product of  claim 1  wherein the fastener elements comprise male fastener elements.  
     
     
         3 . The fastener product of  claim 2  wherein the fastener elements comprise hooks.  
     
     
         4 . The fastener product of  claim 3  wherein the hooks comprise crooks and stems, and the crooks are formed of a shape memory polymer.  
     
     
         5 . The fastener product of  claim 2  wherein a loop-engaging portion of the fastener element is formed of a shape memory polymer, and a stem portion of the fastener is formed of a non-shape memory polymer.  
     
     
         6 . The fastener product of  claim 4  wherein the stems comprise a non-shape memory polymer.  
     
     
         7 . The fastener product of  claim 1  wherein the sheet form backing is formed of a non-shape memory polymer.  
     
     
         8 . The fastener product of  claim 1  wherein the fastener elements comprise more than one shape memory polymer, and the shape memory polymers have different glass transition temperatures.  
     
     
         9 . The fastener product of  claim 1  wherein the glass transition temperature of the shape memory polymer is from about −40 to 150° C.  
     
     
         10 . The fastener product of  claim 1  wherein the glass transition temperature of the shape memory polymer is from about 60 to 100° C.  
     
     
         11 . The fastener product of  claim 1  wherein the shape memory polymer comprises a polyurethane.  
     
     
         12 . The fastener product of  claim 1  wherein the fastener element is configured to change from a metastable hook or mushroom shape to a stable substantially non-engaging shape in response to a temperature change.  
     
     
         13 . The fastener product of  claim 12  wherein the substantially non-engaging shape is a substantially straight stem.  
     
     
         14 . The fastener product of  claim 12  wherein the substantially non-engaging shape is a bent-over hook or mushroom shape.  
     
     
         15 . The fastener product of  claim 1  wherein the fastener element is configured to change from a metastable substantially non-engaging shape to a stable hook or mushroom shape in response to a temperature change.  
     
     
         16 . The fastener product of  claim 15  wherein the substantially non-engaging shape is a substantially straight stem.  
     
     
         17 . The fastener product of  claim 15  wherein the substantially non-engaging shape is a bent-over hook or mushroom shape.  
     
     
         18 . A fastener product comprising 
 a sheet form backing; and    extending from the backing, a plurality of fastener elements comprising two or more shape memory polymers.    
     
     
         19 . The fastener product of  claim 18  wherein each fastener element comprises at least two shape memory polymers.  
     
     
         20 . The fastener product of  claim 18  wherein a first set of the fastener elements comprises a first shape memory polymer, and a second set of the fastener elements comprises a second, different shape memory polymer.  
     
     
         21 . The fastener product of  claim 18  wherein said shape memory polymers are selected to modulate a change in the physical properties of the fastener product as a function of temperature.  
     
     
         22 . A method of forming a fastener product comprising 
 forming a plurality of fastener elements extending from a sheet form base, at least some of the fastener elements comprising a shape memory polymer.    
     
     
         23 . The method of  claim 22  wherein the forming step comprises forming male fastener elements.  
     
     
         24 . The method of  claim 23  wherein the male fastener elements comprise hooks.  
     
     
         25 . The method of  claim 24  wherein the hooks comprise crooks and stems, and the crooks are formed of a shape memory polymer.  
     
     
         26 . The method of  claim 25  wherein the stems comprise a non-shape memory polymer.  
     
     
         27 . The method of  claim 26  further comprising co-extruding the shape memory polymer and the non-shape memory polymer to form the sheet-form base, wherein the forming step includes forming the fastener elements from a portion of the sheet-form base.  
     
     
         28 . The method of  claim 22  wherein the fastener elements comprise more than one shape memory polymer, and the shape memory polymers have different glass transition temperatures.  
     
     
         29 . The method of  claim 28  further comprising co-extruding the shape memory polymers to form the sheet-form base, wherein the forming step includes forming the fastener elements from a portion of the sheet-form base.  
     
     
         30 . The method of  claim 22  wherein the glass transition temperature of the shape memory polymer is from about −40 to 150° C.  
     
     
         31 . The method of  claim 22  wherein the glass transition temperature of the shape memory polymer is from about 60 to 100° C.  
     
     
         32 . The method of  claim 22  wherein the forming step comprises forming fastener elements having a substantially non-engaging shape.  
     
     
         33 . The method of  claim 32  further comprising heating the fastener elements to a formation temperature and deforming the fastener elements to a metastable hook or mushroom shape.  
     
     
         34 . The method of  claim 32  wherein the substantially non-engaging shape is a substantially straight stem.  
     
     
         35 . The method of  claim 32  wherein the substantially non-engaging shape is a bent-over hook or mushroom shape.  
     
     
         36 . The method of  claim 22  wherein the forming step comprises forming fastener elements having a hook or mushroom shape.  
     
     
         37 . The method of  claim 36  further comprising heating the fastener elements to a formation temperature and deforming the fastener elements to a metastable substantially non-engaging shape.  
     
     
         38 . The method of  claim 37  wherein the substantially non-engaging shape is a substantially straight stem.  
     
     
         39 . The method of  claim 37  wherein the substantially non-engaging shape is a bent-over hook or mushroom shape.  
     
     
         40 . A method of attaching a fastener product to a substrate comprising 
 inserting a substantially straight stem of the fastener product through a blind opening in the substrate so that a terminal portion of the stem extends beyond the opening, the stem including a shape memory polymer in a metastable state; and    heating the terminal portion of the stem to a temperature at which the shape memory polymer returns to a stable state in which the configuration of the terminal portion provides an interference fit that prevents the stem from being removed from the opening.    
     
     
         41 . An absorbent article comprising: 
 a disposable garment including an absorbent material; and    a fastener for securing the garment on a wearer, the fastener comprising a female fastener component on a first portion of the garment, and a male fastener component on a second portion of the garment, arranged for cooperative engagement with the female fastener component;    the male fastener component including a plurality of male fastener elements comprising a shape memory polymer.    
     
     
         42 . The absorbent article of  claim 41  wherein the article is selected from the group consisting of diapers and incontinence products.  
     
     
         43 . The absorbent article of  claim 41  wherein the male fastener elements comprise hooks.  
     
     
         44 . The absorbent article of  claim 41  wherein said shape memory polymer is selected to modulate a change in the physical properties of the fastener as a function of temperature.  
     
     
         45 . The absorbent article of  claim 44  wherein said shape memory polymer is selected to modulate the change in the physical properties of the fastener when it is heated from ambient temperature to the surface temperature of a wearer of the article.  
     
     
         46 . A fastener product comprising 
 a sheet form backing comprising a shape memory polymer; and    extending from the backing, a plurality of fastener elements.    
     
     
         47 . The fastener product of  claim 46  wherein the shape memory polymer is selected to modulate the change in the physical properties of the fastener when it is heated from ambient temperature to the surface temperature of a human.  
     
     
         48 . An absorbent article comprising 
 a disposable garment including an absorbent material; and    a fastener for securing the garment on a wearer, the fastener comprising a female fastener component on a first portion of the garment, and a male fastener component on a second portion of the garment, arranged for cooperative engagement with the female fastener component;    the fastener components each including a base comprising a shape memory polymer.    
     
     
         49 . The absorbent article of  claim 48  wherein the shape memory polymer is selected to modulate the change in the physical properties of the fastener when it is heated from ambient temperature to the surface temperature of a wearer of the article.  
     
     
         50 . A method comprising 
 providing a fastener product having a fastener element including a stem and a terminal portion that is crooked at ambient temperature, the stem including a shape memory polymer in a metastable state; and    heating the terminal portion of the fastener element to a temperature at which the shape memory polymer returns to a stable state in which the terminal portion has a different shape.    
     
     
         51 . The method of  claim 50  wherein in the stable state the terminal portion is substantially straight.