Linerless metallic cap closure and method of fabricating the same

Abstract

A linerless metallic closure includes a metallic closure shell, as for example, the type used for crown caps or roll-on caps. A foamed material layer is applied to an inside surface of the metallic shell such that application of the linerless closure to a container hermetically seals it by a contact between a portion of the material layer on the shell and the container's rim. A method of fabricating linerless closures includes providing a metallic sheet; applying a foaming material layer to one of the surfaces of the metallic sheet, and forming the closure from the metallic sheet. The method also comprises applying and curing a coat of varnish, imprinting the metallic sheet with at least one of a brand name a producer logo, and a promotional message, and curing said ink before said applying the foaming material layer.

1 . A linerless metallic closure for a container having an opening with a rim, said linerless metallic closure comprising: 
 a metal closure shell having a top portion and an annular side wall; and    a foamed material layer deposited over an inside surface of said top portion such that application of said closure to said container hermetically seals said container by a contact between a portion of said foamed material layer on said top circular portion and said rim.    
   
   
       2 . The linerless metallic closure of  claim 1 , wherein said foamed material layer is deposited over said inside surface of said top portion and an inside surface of said side wall.  
   
   
       3 . The linerless metallic closure of  claim 1 , wherein said metal closure shell is one of steel, and aluminum.  
   
   
       4 . The linerless metallic closure of  claim 1 , wherein said metal closure shell is one of a crown cap, and a roll-on cap.  
   
   
       5 . The linerless metallic closure of  claim 1 , wherein said metal closure shell further comprises at least one varnish coating thereon.  
   
   
       6 . The linerless metallic closure of  claim 1 , wherein a composition of said foamed material layer comprises a vinyl resin, a plasticizer, and a blowing agent.  
   
   
       7 . The linerless metallic closure of  claim 1 , wherein the thickness of said foamed material layer is between about 0.010 and about 0.020 inches.  
   
   
       8 . The linerless metallic closure of  claim 7 , wherein the thickness of said foamed material layer is about 0.015 inches.  
   
   
       9 . The linerless metallic closure of  claim 6 , wherein said vinyl resin is a polyvinyl chloride having a concentration in said composition ranging from about 40 to about 50% by weight.  
   
   
       10 . The linerless metallic closure of  claim 9 , wherein said concentration is about 45% by weight.  
   
   
       11 . The linerless metallic closure of  claim 6 , wherein said plasticizer is at least one of a di-octil phthalate (DOP), and a di-isodecyl phthalate (DIP) having a concentration in said composition varying between about 50 and about 55% by weight.  
   
   
       12 . The linerless metallic closure of  claim 11 , wherein said concentration is about 52.5% by weight.  
   
   
       13 . The linerless metallic closure of  claim 11 , wherein said DOP plasticizer has the following chemical formula:  
     
       
         
         
             
             
         
       
     
   
   
       14 . The linerless metallic closure of  claim 6 , wherein said blowing agent is one of a azodicarbonamide (ADC), a modified azodicarbonamide (MADC), a dinitrosopentametilentetramine (DNPT), a benzensulfonil hidracide (BSH), a 4,4 oxibisbenzene sulfonyl hidrazide (OBSH), a toluensulfonyl semicarbazide (TSSC), a 5-penyltrazole, a derived hydrazide, and a sodium bicarbonate (SBC).  
   
   
       15 . The linerless metallic closure of  claim 14 , wherein a concentration of said blowing agent in said composition varies from about 1 to about 5% by weight.  
   
   
       16 . The linerless metallic closure of  claim 15 , wherein said composition is about 2.5% by weight.  
   
   
       17 . A method for manufacturing a linerless metallic closure, comprising: 
 providing a metallic sheet having a top surface and a bottom surface;    applying a foaming material layer to one of said surfaces; and    forming said closure from said metallic sheet.    
   
   
       18 . The method of  claim 17 , further comprising applying a coat of varnish to said metallic sheet and curing said coat of varnish before said applying said foam material layer.  
   
   
       19 . The method of  claim 18 , further comprising transferring an ink to said metallic sheet, so as to imprint thereon at least one of a brand logo, a producer logo, and a promotional message, and curing said ink before said applying said foam material layer.  
   
   
       20 . The method of  claim 19 , wherein said foaming material layer foams during a curing of said foaming material layer.  
   
   
       21 . The method of  claim 17 , wherein said foaming material layer comprises a combination of a vinyl resin, a plasticizer, and a blowing agent.  
   
   
       22 . The method of  claim 21 , further comprising curing said foaming material layer in an environment having a temperature varying from about 180 to about 220° C.  
   
   
       23 . The method of  claim 22 , wherein said temperature varies from about 192 to about 198° C.  
   
   
       24 . The method of  claim 22 , wherein a curing time of said foaming material layer in said environment varies from about 1.5 to about 5 minutes.  
   
   
       25 . The method of  claim 24 , wherein said curing time varies from about 2 to about 2.5 minutes.  
   
   
       26 . The method of  claim 17 , wherein a thickness of said foaming material layer is between about 0.010 and 0.020 inches.  
   
   
       27 . The method of  claim 26 , wherein said thickness is about 0.015 inches.  
   
   
       28 . A method for manufacturing a linerless metallic closure, comprising: 
 providing a metallic sheet;    forming at least one closure shell from said metallic sheet, said at least one closure shell having a top portion and an annular side wall; and    applying a foaming material layer to an inner surface of said top portion.    
   
   
       29 . A method for manufacturing a linerless metallic closure, comprising: 
 providing a roll-on metallic closure shell having a top portion and an annular side wall; and    applying a foaming material layer to an inner surface of said top portion.    
   
   
       30 . The method of  claim 29 , wherein said applying further comprises applying said foaming material layers over an inner surface of said side wall.