Chemical vapor resistant epoxy composition

Abstract

A two part, curable, epoxy composition useful for potting or sealing electrical devices for use in hazardous locations. Cured reaction products of the epoxy composition meet most or all UL 674 requirements and are useful to seal apertures in electrical equipment. Equipment sealed with the disclosed compositions can meet the UL 674 requirement.

What is claimed: 
     
         1 . A two part, epoxy composition suitable for sealing equipment for use in Division 1 hazardous locations, comprising two reactive components:
 an epoxy resin component comprising a novolac epoxy resin, a bisphenol F epoxy resin or a mixture thereof; and   a curing agent component separated from the epoxy resin component, comprising an adduct of an amine and an epoxy resin.   
     
     
         2 . The two part epoxy composition of  claim 1  wherein the epoxy resin component consists essentially of a novolac epoxy resin, a bisphenol F epoxy resin or a mixture thereof. 
     
     
         3 . The two part epoxy composition of  claim 1  wherein a mixture of 2 parts by volume epoxy resin component to 1 part by volume curing agent component has an initial viscosity of about 8,000 to about 30,000 cps. 
     
     
         4 . The two part epoxy composition of  claim 1  wherein a mixture of 2 parts by volume epoxy resin component to 1 part by volume curing agent component has an initial viscosity of about 15,000 cps. 
     
     
         5 . The two part epoxy composition of  claim 1  which does not include a bisphenol A epoxy resin. 
     
     
         6 . The two part epoxy composition of  claim 1  wherein the curing agent component does not include an adduct of an amine and a bisphenol A epoxy resin. 
     
     
         7 . The two part epoxy composition of  claim 1  wherein the curing agent component does not include an adduct of an amine and a bisphenol A epoxy resin. 
     
     
         8 . The two part epoxy composition of  claim 1  wherein a cured reaction product of a mixture of 2 parts by volume epoxy resin component to 1 part by volume curing agent component meets the requirements of UL 674, section 45. 
     
     
         9 . The two part, epoxy composition of  claim 1 , further comprising at least one of 2-furanmethanol and benzyl alcohol. 
     
     
         10 . The two part epoxy composition of  claim 1  having a maximum exotherm temperature of 150° C. when tested by Differential Scanning calorimetry. 
     
     
         11 . The two part epoxy composition of  claim 1  wherein a mixture of 2 parts by volume epoxy resin component to 1 part by volume curing agent component will self level. 
     
     
         12 . Cured reaction products of the two part, epoxy composition of  claim 1 . 
     
     
         13 . An electrical device, comprising:
 a housing defining an aperture providing a route between a housing exterior and a housing interior volume; and cured reaction products of the two part, epoxy composition of  claim 1  sealing the aperture, wherein the electrical device is suitable for use in Division 1 hazardous locations.   
     
     
         14 . The electrical device of  claim 13 , comprising a wire disposed through the aperture and the cured reaction products. 
     
     
         15 . The electrical device of  claim 13 , wherein the electrical device is compliant with UL 674. 
     
     
         16 . A method of using an epoxy composition to seal an electrical device, comprising
 providing an electrical device having a housing enclosing an interior space and having an exterior surface, the exterior surface defining an aperture providing communication into and out of the interior space;   disposing the epoxy composition of  claim 1  into the housing aperture;   exposing the epoxy composition to conditions appropriate to cure the epoxy composition to form cured reaction products in the housing aperture;   wherein the cured reaction products seal the housing interior space and the electrical device is suitable for use in Division 1 hazardous locations.   
     
     
         17 . The method of  claim 16 , comprising a wire disposed through the aperture and the cured reaction products. 
     
     
         18 . The method of  claim 16 , wherein the electrical device is compliant with UL 674.