Binder for preforms in silencers

Abstract

In a method of forming a silencer preform from fibers of a fiberizable material, the fibers are fed into a mold, and a low temperature cure binder is applied to the fibers. The binder is cured at a low temperature to bond together the fibers, thereby forming a preform having generally the shape of the mold. The preform is removed from the mold. The preform is structured for insertion into a silencer. A silencer preform includes fibers of a fiberizable material and a low temperature cure binder bonding together the fibers.

1 . A method of forming a silencer preform from fibers of a fiberizable material comprising the steps of:
 feeding the fibers into a mold;   applying a low temperature cure binder to the fibers before or after the fibers are fed into the mold;   curing the binder at a low temperature to bond together the fibers thereby forming the preform having generally the shape of the mold; and   removing the preform from the mold, the preform being structured for insertion into a silencer.   
   
   
       2 . The method of  claim 1  wherein the curing is done without applying heat to the binder. 
   
   
       3 . The method of  claim 1  wherein the curing is completed in a time of not greater than about 20 minutes. 
   
   
       4 . The method of  claim 1  wherein the binder is cured at a temperature not greater than about 35° C. 
   
   
       5 . The method of  claim 1  wherein the binder is applied in an amount within a range of from about 1% to about 20% by weight of the final preform. 
   
   
       6 . The method of  claim 1  wherein the binder is substantially nontoxic, such that when the preform is heated to a temperature of 250° C., the binder emits not greater than the OSHA permissible exposure limits of toxic gases. 
   
   
       7 . The method of  claim 1  wherein the binder comprises a resin and a curing promoter. 
   
   
       8 . The method of  claim 7  wherein the curing promoter is a liquid. 
   
   
       9 . The method of  claim 7  wherein the resin comprises an alkaline modified phenolic resin. 
   
   
       10 . The method of  claim 7  wherein the resin and the curing promoter are applied separately to the fibers. 
   
   
       11 . The method of  claim 1  wherein at least a portion of the binder is applied to the fibers using pressurized application equipment. 
   
   
       12 . The method of  claim 1  comprising an additional step of adding a viscosity modifier to at least a portion of the binder before applying the portion to the fibers. 
   
   
       13 . The method of  claim 1  wherein the mold is perforated. 
   
   
       14 . The method of  claim 1  wherein the mold is made partially or entirely of elastomeric material. 
   
   
       15 . The method of  claim 1  comprising an additional step of applying a release agent to the mold prior to feeding the fibers into the mold. 
   
   
       16 . The method of  claim 1  wherein the fiberizable material comprises glass. 
   
   
       17 . The method of  claim 1  wherein the fibers are texturized. 
   
   
       18 . The method of  claim 1  wherein the silencer is a component of an automotive exhaust system. 
   
   
       19 . A method of forming an automotive exhaust preform from fibers of a fiberizable material comprising the steps of:
 feeding the fibers into a mold;   applying a low temperature cure binder to the fibers before or after the fibers are fed into the mold;   curing the binder at a temperature not greater than about 50° C. and for a time of not greater than about 20 minutes, and without applying heat to the binder, to bond together the fibers thereby forming the preform having generally the shape of the mold; and   removing the preform from the mold, the preform being structured for insertion into an automotive exhaust component.   
   
   
       20 . A silencer preform comprising:
 fibers of a fiberizable material; and   a low temperature cure binder bonding together the fibers to form the preform;   the preform being structured for insertion into a silencer.   
   
   
       21 . The preform of  claim 20  wherein the automotive exhaust component is a muffler.