Heat-curable eproxy resin composition

Abstract

The invention relates to compositions containing at least one epoxy resin A with on average more than one epoxy group per molecule; at least one epoxy adduct B with on average one epoxy group per molecule; at least one thixotropic agent C, based on a urea derivative in a non-diffusing support material; and at least one curing agent D for epoxy resins, which is activated by an increased temperature. According to preferred embodiments, the invention also relates to compositions containing at least one core-shell polymer E and/or filler F and/or reactive diluent G. The invention also relates to the use of said compositions as a single-component adhesive and to a method for producing the compositions. The invention further relates to the use of the thixotropic agent C, based on a urea derivative in a non-diffusing support material as an agent for increasing the impact resistance.

1 . Composition comprising 
 at least one epoxy resin A with more than one epoxy group per molecule on the average;    at least one epoxy adduct B, each with more than one epoxy group per molecule on the average;    at least one thixotropic agent C, based on a urea derivative in a non-diffusing carrier;    at least one curing agent D for epoxy resins which is activated by elevated temperature.    
     
     
         2 . Composition as in  claim 1 , distinguished by the fact that the epoxy resin A is a liquid resin, in particular a bisphenol-A diglycidyl ether, bisphenol-F diglycidyl ether, or bisphenol-A/F diglycidyl ether.  
     
     
         3 . Composition as in  claim 1 , distinguished by the fact that the epoxy adduct B 
 is an epoxy adduct B1, which can be obtained from at least one dicarboxylic acid and at least one diglycidyl ether;    and is optionally combined with    an epoxy adduct B2, which can be obtained from at least one bis(aminophenyl)sulfone isomer or at least one aromatic alcohol and at least one diglycidyl ether.    
     
     
         4 . Composition as in  claim 3 , distinguished by the fact that for preparation of the epoxy adduct B1, a dimeric fatty acid, in particular at least one dimeric C4-C20 fatty acid, is used as the dicarboxylic acid and bisphenol-A diglycidyl ether, bisphenol-F diglycidyl ether, or bisphenol-A/F diglycidyl ether is used as the diglycidyl ether.  
     
     
         5 . Composition as in  claim 3 , distinguished by the fact that preparation of the epoxy adduct B2 uses an aromatic alcohol selected from the group 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, hydroquinone, resorcinol, pyrocatechol, naphthohydroquinone, naphthoresorcinol, dihydroxynaphthalene, dihydroxyanthraquinone, dihydroxybiphenyl, 3,3-bis(p-hydroxyphenyl)phthalide, 5,5-bis(4-hydroxyphenyl)hexahydro-4,7-methanoindane, as well as all isomers of the aforementioned compounds, or [sic] 1 , and bisphenol-A diglycidyl ether, bisphenol-F diglycidyl ether, or bisphenol-A/F diglycidyl ether as the diglycidyl ether.  
     
     
         6 . Composition as in  claim 1 , distinguished by the fact that the epoxy adduct B has a molecular weight of 700-6000 g/mol, preferably 900-4000 g/mol, in particular 1000-3300 g/mol.  
     
     
         7 . Composition as in  claim 1 , distinguished by the fact that the carrier for the thixotropic agent C is a blocked polyurethane prepolymer.  
     
     
         8 . Composition as in  claim 7 , distinguished by the fact that the urea derivative in the thixotropic agent C is the product of reaction between an aromatic monomeric diisocyanate, in particular 4,4′-diphenylmethylene diisocyanate, and an aliphatic amine compound, in particular butylamine.  
     
     
         9 . Composition as in  claim 1  distinguished by the fact that the curing agent D is a latent curing agent from the group dicyanodiamide, guanamine, guanidine, and aminoguanidine.  
     
     
         10 . Composition as in  claim 1 , distinguished by the fact that the total proportion of epoxy resin A and epoxy adduct B together is 20-70 wt. %, preferably 35-65 wt. %, based on the weight of the total composition.  
     
     
         11 . Composition as in  claim 1 , distinguished by the fact that the total proportion of epoxy resin A is 12-50 wt. %, preferably 17-45 wt. %, based on the sum of the weights for A+B.  
     
     
         12 . Composition as in  claim 1 , distinguished by the fact that the total proportion of the thixotropic agent C is 5-40 wt-%, preferably 10-25 wt. %, based on the weight of the total composition.  
     
     
         13 . Composition as in  claim 12 , distinguished by the fact that the proportion of the urea derivative is 5-50 wt. %, preferably 15-30 wt. %, based on the weight of the thixotropic agent C.  
     
     
         14 . Composition as in  claim 1 , distinguished by the fact that the total proportion of the curing agent D is 1-6 wt-%, preferably 2-4 wt. %, based on the weight of the total composition.  
     
     
         15 . Composition as in  claim 1 , distinguished by the fact that in addition, at least one core/shell polymer E is present.  
     
     
         16 . Composition as in  claim 15 , distinguished by the fact that the total proportion of the core/shell polymer E is 3-20 wt. %, preferably 5-12 wt. %, based on the weight of the total composition.  
     
     
         17 . Composition as in  claim 1 , distinguished by the fact that the core of the core/shell polymer E consists of a polymer with a glass transition temperature of −30° C. or lower, and the shell of the core/shell polymer E consists of a polymer with a glass transition temperature of 70° C. or higher.  
     
     
         18 . Composition as in  claim 1 , distinguished by the fact that in addition, at least one filler F is present.  
     
     
         19 . Composition as in  claim 18 , distinguished by the fact that the total proportion of the filler F is 5-30 wt. %, preferably 10-25 wt. %, based on the weight of the total composition.  
     
     
         20 . Composition as in  claim 1 , distinguished by the fact that in addition, at least one reactive diluent G with epoxy groups is present.  
     
     
         21 . Composition as in  claim 1 , distinguished by the fact that the heat-cured composition has a glass transition temperature of at least 85° C.  
     
     
         22 . Process for preparation of a composition as in  claim 1 , distinguished by the fact that the preparation includes at least one adduct formation step carried out with a diglycidyl ether.  
     
     
         23 . Use of a composition as in  claim 1  as a one-component adhesive.  
     
     
         24 . Use as in  claim 23 , distinguished by the fact that the adhesive is used to bond heat-stable materials, in particular metals.  
     
     
         25 . Use as in  claim 23 , distinguished by the fact that the adhesive is used as a bodyshell adhesive in automobile construction.  
     
     
         26 . Use of the thixotropic agent C, based on a urea derivative in a non-diffusing carrier, as a means to increase impact strength.  
     
     
         27 . Use of the thixotropic agent C as in  claim 26 , distinguished by the fact that the carrier C [sic] is a blocked polyurethane prepolymer.  
     
     
         28 . Use of the thixotropic agent C as in  claim 26 , distinguished by the fact that the urea derivative is the product of reaction between an aromatic monomeric diisocyanate, in particular 4,4′-diphenylmethylene diisocyanate, and an aliphatic amine compound, in particular butylamine.  
     
     
         29 . Use of the thixotropic agent C as in  claim 26 , distinguished by the fact that the proportion of the urea derivative is 5-50 wt. %, preferably 15-30 wt. %, based on the weight of the thixotropic agent C.  
     
     
         30 . Process for bonding heat-stable materials, in particular metals, distinguished by the fact that these materials are in contact with a composition as in  claim 1  and a curing step at a temperature of 120° C.-220° C., preferably 150° C.-200° C., [is] included.