Two stage sealants and method of forming and/or using the same

Abstract

A sealant is configured to activate (e.g., cure and/or foam) in two stages (e.g., of two distinct portions of time). Advantageously, the sealant can exhibit self supporting characteristics during the second activation at least partly because of the first activation.

1 . A method of baffling or sealing a structure, the method comprising:
 providing a sealer, the sealer being formed of an activatable sealant material, wherein:
 i. the sealant material undergoes a first activation to expand, cure or both at a first temperature that is at least about 10° C. and less than about 140° C.; and 
 ii. the sealant material is at least 85% by weight of the sealer; 
   locating the sealer within a cavity of a structure of an automotive vehicle, wherein:
 i. the sealant material undergoes a second activation to foam and cure at a second temperature that is at least about 150° C. and less than about 300° C. and adheres to walls of the structure; 
 ii. the sealant material expands to a volume that is at least 400% its original unexpanded volume during the first activation, the second activation or both; and 
 iii. the sealant material exhibits self supporting characteristics during the second activation because of the first activation. 
   
   
   
       2 . A method as in  claim 1  wherein the sealer includes a fastener that attaches the sealer to the structure. 
   
   
       3 . A method as in  claim 2  wherein the fastener is formed of the sealant material. 
   
   
       4 . A method as in  claim 1  wherein the sealer is a baffle that, after the second activation, continuously spans across a cross-section of the cavity for inhibiting passage of mass, sound or both through the cavity. 
   
   
       5 . A method as in  claim 1  wherein the step of providing the sealer includes extruding the sealant material at the first temperature of activation. 
   
   
       6 . A method as in  claim 1  wherein the sealant material includes one or more ethylene based polymers. 
   
   
       7 . A method as in  claim 6  wherein the one or more ethylene based polymers includes EVA, EMA, EPDM or any combination thereof. 
   
   
       8 . A method as in  claim 7  wherein the one or more ethylene based polymers are at least about 10% and less than about 65% by weight of the sealant material. 
   
   
       9 . A method as in  claim 1  wherein the sealant material expands to a volume that is at least 800% its original unexpanded volume during the first activation, the second activation or both. 
   
   
       10 . A method as in  claim 1  wherein the sealant material includes an acid functionalized elastomer and an epoxy resin that react with each other during the first activation. 
   
   
       11 . A method as in  claim 1  wherein the sealant material includes a peroxy curing agent and a peroxy-curable polymer that cures during the first activation. 
   
   
       12 . A method as in  claim 1  wherein the sealant material includes a relatively low amount of epoxy resin and a relatively low amount of epoxy curative that cures the epoxy resin during the first activation. 
   
   
       13 . A method as in  claim 1  wherein the sealant material includes a blowing agent that foams the sealant material during the first activation. 
   
   
       14 . A method as in  claim 1  wherein the sealant material includes a relatively light weight and relatively high melt viscosity polymer for assisting in exhibiting self supporting characteristics 
   
   
       15 . A method of baffling or sealing a structure, the method comprising:
 providing a sealer, the sealer being formed of an activatable sealant material, wherein:
 i. the sealant material undergoes a first activation to expand, cure or both at a first temperature that is at least about 10° C. and less than about 140° C.; 
 ii. the sealant material is at least 85% by weight of the sealer; 
 iii. the step of providing the sealer includes extruding the sealant material at the first temperature of activation; and 
 iv. the sealant material includes one or more ethylene based polymers selected from EVA, EMA and EPDM, the one or more ethylene polymer being at least about 10% and less than about 65% by weight of the sealant material; 
   locating the sealant material within a cavity of a structure of an automotive vehicle, wherein:
 i. the sealant material undergoes a second activation to foam and cure at a second temperature that is at least about 150° C. and less than about 300° C. and adheres to walls of the structure; 
 ii. the sealant material expands to a volume that is at least 800% its original unexpanded volume during the first activation, the second activation or both; and 
 iii. the sealant material exhibits self supporting characteristics during the second activation because of the first activation; wherein 
 iv. the sealer is a baffle that, after the second activation, continuously span across a cross-section of the cavity for inhibiting passage of mass, sound or both through the cavity; and 
   wherein, either:
 i. the sealant material includes an acid functionalized elastomer and an epoxy resin that react with each other during the first activation; 
 ii. the sealant material includes a peroxy curing agent and a peroxy-curable polymer that cures during the first activation; or 
 iii. the sealant material includes a relatively low amount of epoxy resin and a relatively low amount of epoxy curative that cures the epoxy resin during the first activation. 
   
   
   
       16 . A method as in  claim 15  wherein the sealer includes a fastener that attaches the sealer to the structure and the fastener is a thermoplastic push pin. 
   
   
       17 . A method as in  claim 16  wherein the sealant material includes a blowing agent that foams the sealant material during the first activation. 
   
   
       18 . A method as in  claim 17  wherein the sealant material includes a relatively light weight and relatively high melt viscosity polymer for assisting in exhibiting self supporting characteristics