Slide fastener
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to slide fasteners and more particularly to such a slide fastener which is suitable for dyeing simultaneously with a garment article to which the fastener is attached. 
     2. Prior Art 
     Amongst a variety of slide fasteners is known one which is fully separable into identical halves by means of a separator including a pin and a socket member. To facilitate separation of the slide fastener, there are provided reinforcing strips at both upper and lower end portions of the fastener tapes, the reinforcing strips being secured usually by fusion of an adhesive film to the respective tape ends to render the latter ends rigid enough. The reinforcing strips in common use are made predominantly of nylon and initially dyed to match the color of a given slide fastener tape. Such reinforcing strips are attached by an adhesive film of mostly commonly polyester with heat and pressure to the respective end portions of the fastener tape. 
     In light of the recent trend of the garment industry which demands shortened delivery terms, small lot production, reduced inventories and a minimum risk of speculative production, it has been a common practice to dye garment articles in their final product form rather than pre-dyeing the starting fabric materials. To cope with this trend, it has also been proposed to dye slide fasteners of the separable type simultaneously with the particular garment article to which the fastener is attached. However, difficulties were encountered in achieving homogeneity and regularity in the hues between the fastener stringer tapes and the reinforcing strips attached thereto. Another drawback was found in separation or peel-off of the adhesive film used to bond the reinforcing strip to the tape. 
     SUMMARY OF THE INVENTION 
     With the foregoing drawbacks of the prior art in view, the present invention seeks to provide a slide fastener having reinforcing end strips which can be dyed homogeneously and simultaneously with the dyeing of a garment article to which the fastener is attached. 
     The invention further seeks to provide a separable type of slide fastener having reinforcing end strips which can be retained in place against separation from the fastener even after being dyed. 
     Therefore, by the practice of the invention it is made possible to eliminate the necessity of over-inventories and the risk of speculative production, to enhance the rate of slide fastener yields, and to dye the slide fastener simultaneously with an ultimate garment article. 
     The above objects of the invention can be achieved by the selection of particular materials for fastener stringer tapes, reinforcing strips and adhesive films, respectively, and the selection of particular dyes and dyeing conditions  whereby the fastener tape and the reinforcing strip can be dyed homogeneously and can be firmly bonded together. 
     According to one aspect of the invention, there is provided a slide fastener comprising a pair of stringer tapes each carrying thereon a row of coupling elements, said stringer tapes being made of undyed polyester fiber, a reinforcing strip attached to an end of each of said tapes, said strip being made of undyed polyester fiber and an adhesive film adapted to bond said reinforcing strip to said tape end, said film being made of a modified polyester melting in the range of 160°-200° C., preferably 165°-175° C. 
     According to another aspect of the invention, there is provided a slide fastener comprising a pair of stringer tapes and a reinforcing strip, both of said tape and said strip being made of undyed nylon fibers, and an adhesive film made of a copolymeric polyamide melting above 140° C. and adapted to bond said reinforcing strip to an end of each of said tapes. 
     According to a further aspect of the invention, there is provided a slide fastener comprising a pair of stringer tapes and a reinforcing strip, both of said tapes and said strip being made of undyed cotton fibers and an adhesive film made of a copolymeric polyamide melting above 140° C. and adapted to bond said reinforcing strip to an end of each of said tapes. 
     The invention will be described in greater detail with reference to certain preferred embodiments illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary plan view of a separable type of slide fastener to which the principles of the invention are applied; 
     FIG. 2 is a plan view of the slide fastener shown in separated disposition; and 
     FIG. 3 is a plan view of the upper end portions of the slide fastener. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings and FIG. 1 in particular, there is shown a separable type of slide fastener 10 which comprises a pair of stringer tapes 11, 12 each carrying along its inner longitudinal edge a row of coupling elements 13 which are illustrated to be in the form of a continuous helical coil. Two oppositely disposed rows of coupling elements 13 are taken into and out of engagement with each other by a slider 14 in a manner well known in the art. 
     A separator 15 comprises a pin member 16 and a box member 17, the pin member 16 having secured to the inner edge of one tape 11 at the lower end thereof and the box member 17 being secured to the inner edge of the other tape 12 at the lower end thereof. The pin member 16 is releasably engageable in a slot in the box member 17 and is manipulated to join together as shown in FIG. 1 and separate as shown in FIG. 2 the identical halves of the fastener 10. 
     A reinforcing strip 18 is attached to a lower end portion of each of the paired tapes 11, 12 to provide reinforced physical strength at that end portion. A similar reinforcing strip 19 is applied for the same purpose to an upper end portion of each of the tapes 11, 12. 
     An adhesive film 20 is interposed between each tape 11, (12) and the reinforcing strip 18, (19) and adapted to bond the latter to the former with heat and pressure in a manner well known in the art. 
     The slide fastener 10 thus constructed appears no more different from any ordinary separable slide fastener except that the fastener 10 according to the invention is undyed. 
     Typical materials for slide fastener tapes 11, 12 currently used in consideration of the type of fabric materials for various garment articles include nylon 6 or 66, polyester, cotton and similar fibrous materials which are woven or knitted into tapes of standard sizes. 
     Extensive research and experimental work has been conducted in an effort to reach a specific material for each of the reinforcing strip 18, (19) and the adhesive film 20 which excels in respect of the adhesiveness between the reinforcing strip and the tape 11, (12) prior to dyeing the separation therebetween subsequent to dyeing and the dye homogeneousness. 
     It has not been found that certain specific combinations of selected materials for tape 11, (12), reinforcing strip 18, (19) and adhesive film 20, respectively, will provide improved strip-to-tape adhesiveness, homogeneous dye finish, and increased resistance to separation (peel-off) between the strip and the tape after they have been dyed. Preferred examples of such material combinations according to the invention are represented in Inventive Examples 1, 2 and 3 and below which are tabulated along with other comparative combinations in the Table. 
     INVENTIVE EXAMPLE 1 
     
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Stringer tape Polyester                                                   
Reinforcing strip                                                         
              Polyester                                                   
Adhesive film modified polyester melting at 170° C.                
Dye           Dispersion type                                             
Dyeing conditions                                                         
              130° C. for 30-40 minutes                            
Physical qualities                                                        
Adhesiveness  excellent                                                   
Dye homogeneousness                                                       
              excellent                                                   
Resistance to peel-off                                                    
              excellent                                                   
of reinforce strip                                                        
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     INVENTIVE EXAMPLE 2 
     
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Stringer tape   Nylon 6 (or 66)                                           
Reinforcing strip                                                         
                Nylon 6 (or 66)                                           
Adhesive film   Copolymeric polyamide,                                    
                melting at 145° C.                                 
Dye             Acidic type                                               
Dyeing conditions                                                         
                98° C.-100° C. for 30-40 minutes            
Physical qualities                                                        
Adhesiveness    excellent                                                 
Dye homogeneousness                                                       
                excellent                                                 
Resistance to peel-off                                                    
                excellent                                                 
of reinforce strip                                                        
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     INVENTIVE EXAMPLE 3 
     
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Stringer tape Cotton                                                      
Reinforcing strip                                                         
              Cotton                                                      
Adhesive film Copolymeric polyamide,                                      
              melting at 145° C.                                   
Dye           Direct or Reactive type                                     
Dyeing conditions                                                         
              90° C.-95° C. for 50 minutes for              
              direct type, and 60° C. for 60 minutes               
              for reactive type                                           
Physical qualities                                                        
Adhesiveness  excellent                                                   
Dye homogeneousness                                                       
              excellent                                                   
Resistance to peel-off                                                    
              excellent                                                   
of reinforce strip                                                        
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     Adhesiveness of the strip 18, (19) to the tape 11, (12) prior to dyeing is considered excellent if the strip is not peeled off under the influence of in excess of 1,000 g/cm pull force. 
     On evaluation of the results of the quality tests it has now been found that the material of the adhesive film 20 plays an important sole in respect of adhesive strength and when it is the same as or similar to the material of the stringer tape 11, (12) (except for cotton), highly satisfactory adhesion between the strip 18, (19) and the tape 11, (12) can be achieved. It has also been found that better results in respect of homogeneous dye finish can be obtained with the use of similar materials for both the stringer tape (except for nylon 6 or 66) and the reinforcing strip, the adhesive film being not directly associated. In respect of separation or peel-off of the reinforcing strip after being dyed, it is more to the dye bath temperature and the melting point of the adhesive film than to the reinforcing strip that the results are attributed, and it has further been found that the material for the adhesive film is associated with a stringer tape of polyester, but not with stringer tapes of nylon 6 (or 66) and cotton. 
     Obviously, various modifications and variations of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. 
     
                                           TABLE                                   
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           Reinforcing tape                                               
           Polyester      Nylon 6 (or 66)                                 
                                         Cotton                           
           Dye                                                            
           Dispersion type                                                
                          Acidic type                                     
           Dyeing Conditions             Direct or Reactive type          
                                         90°-95° C. for 50  
                                         mins. for                        
                                         direct type, and 60° C.   
                                         for                              
           130° C. for 40 mins.                                    
                          98°-100° C. for 30-40             
                                         60 mins. for reactive type       
           Physical qualities                                             
Stringer                                                                  
     Adhesive                                                             
           Adhe-                                                          
                Dye homo-                                                 
                       Peel                                               
                          Adhe-                                           
                               Dye homo-                                  
                                      Peel-                               
                                         Adhe-                            
                                              Dye homo-                   
                                                     Peel-                
tape film  siveness                                                       
                geneousness                                               
                       off                                                
                          siveness                                        
                               geneousness                                
                                      off                                 
                                         siveness                         
                                              geneousness                 
                                                     off                  
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Nylon 6                                                                   
     modified                                                             
           o    x      x  x    x      o  x    x      o                    
(or 66)                                                                   
     polyester                                                            
           o    o      x  x    x      o  x    x      o                    
polyester                                                                 
     melting                                                              
           o    x      x  x    x      o  x    o      o                    
cotton                                                                    
     at 138° C.                                                    
Nylon 6                                                                   
     modified                                                             
           o    x      o  x    x      o  x    x      o                    
(or 66)                                                                   
     polyester                                                            
           o    o      o  x    x      o  x    x      o                    
polyester                                                                 
     melting                                                              
           o    x      o  x    x      o  x    o      o                    
cotton                                                                    
     at 170° C.                                                    
Nylon 6                                                                   
     copoly-                                                              
           x    x      x  o    o      x  o    x      x                    
(or 66)                                                                   
     meric x    o      x  o    x      x  o    x      x                    
polyester                                                                 
     polyester                                                            
           x    x      x  o    x      x  o    o      x                    
cotton                                                                    
     melting                                                              
     at 130° C.                                                    
Nylon 6                                                                   
     copoly-                                                              
           x    x      x  o    o      o  o    x      o                    
(or 66)                                                                   
     meric x    o      x  o    x      o  o    x      o                    
polyester                                                                 
     polyester                                                            
           x    x      x  o    x      o  o    o      o                    
cotton                                                                    
     melting                                                              
     at 145° C.                                                    
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 o: excellent                                                             
 x: poor