Method of producing epoxy compound, epoxy resin composition and its applications, ultraviolet rays-curable can-coating composition and method of producing coated metal can

Abstract

The invention I provides a method of producing an alicyclic epoxy compound having a specific structure, which comprises epoxidizing an alicyclic olefin compound having a specific structure by using an aliphatic percarboxylic acid having low water content. The alicyclic epoxy compound is useful for use in coatings, inks, adhesives, sealants, encapsulants, stabilizers or the like. The invention II provides an epoxy resin composition containing the alicyclic epoxy compound as a main component, and a photosemiconductor device comprising a photosemiconductor element encapsulated with the epoxy resin composition. The epoxy resin composition can be cured by heating, thereby obtaining a cured product having excellent moisture and heat resistance and transparency. The invention III provides: an ultraviolet rays-curable can-coating composition containing the alicyclic epoxy compound as a main component, which can be cured by ultraviolet irradiation, and can form a coating film having excellent film performances such as processability, adhesion, hardness and scratch resistance, particularly film appearance and retort resistance; and a process of producing a coated metal can using the composition.

What is claimed is:  
     
         1 . A method of producing an alicyclic epoxy compound (A) represented by the following formula (I):  
       
         
           
           
               
               
           
         
       
       (wherein X represents a divalent group selected from oxygen atom, sulfur atom, —SO—, —SO 2 —, —CH 2 —, —C(CH 3 ) 2 —, —CBr 2 —, —C(CBr 3 ) 2 —, —C(CF 3 ) 2 —, —C(CCl 3 ) 2 — and —CH(C 6 H 5 )—, or a single bond linking two alicyclic rings; and R 1  to R 18  are the same or different and each represents one of hydrogen atom, halogen atom, a hydrocarbon group which may contain oxygen atom or halogen atom, and an alkoxyl group which may have substituent groups), which comprises epoxidizing an alicyclic olefin compound represented by the above formula (II) using an aliphatic percarboxylic acid having water content of 2% by weight or less.  
     
     
         2 . The method of producing an alicyclic epoxy compound (A) according to  claim 1 , wherein the aliphatic percarboxylic acid is obtained by oxidation of the corresponding aldehyde with oxygen.  
     
     
         3 . The method of producing an alicyclic epoxy compound (A) according to  claim 1  or  2 , wherein the water content in the aliphatic percarboxylic acid is 0.8% by weight or less.  
     
     
         4 . The method of producing an alicyclic epoxy compound (A) according to any one of  claims 1  to  3 , wherein the aliphatic percarboxylic acid is peracetic acid.  
     
     
         5 . A liquid epoxy resin composition comprising an epoxy resin, and a curing agent and/or a curing accelerator, wherein the epoxy resin comprises, in an amount of 100 to 20% by weight, an alicyclic epoxy compound (A) represented by the following formula (I):  
       
         
           
           
               
               
           
         
       
       (wherein X represents a divalent group selected from oxygen atom, sulfur atom, —SO—, —SO 2 —, —CH 2 —, —C(CH 3 ) 2 —, —CBr 2 —, —C(CBr 3 ) 2 —, —C(CF 3 ) 2 —, —C(CCl 3 ) 2 — and —CH(C 6 H 5 )—, or a single bond linking two alicyclic rings; and R 1  to R 18  are the same or different and each represents one of hydrogen atom, halogen atom, a hydrocarbon group which may contain oxygen atom or halogen atom, and an alkoxyl group which may have substituent groups).  
     
     
         6 . The liquid epoxy resin composition according to  claim 5 , wherein the alicyclic epoxy compound (A) represented by the formula (I) is an epoxy compound produced by using percarboxylic acid having water content of 2% by weight or less.  
     
     
         7 . The liquid epoxy resin composition according to  claim 5  or  6 , wherein the curing agent is an initiator which releases a substance initiating cationic polymerization by heating.  
     
     
         8 . The liquid epoxy resin composition according to any one of  claims 5  to  7 , wherein the curing agent is a liquid acid anhydride.  
     
     
         9 . A liquid epoxy resin composition which is obtained by one of: 
 adding 110 to 160 parts by weight of a liquid acid anhydride curing agent and 3 to 7 parts by weight of a curing accelerator to 100 parts by weight of the alicyclic epoxy compound (A) as set forth in  claim 6;  and    further adding 0.1 to 20 parts by weight of an initiator (E) that releases cation species by heating to 100 parts by weight of the alicyclic epoxy compound (A) represented by the formula (I).    
     
     
         10 . The liquid epoxy resin composition as claimed in any one of  claims 5  to  9 , which is used for photosemiconductor encapsulation.  
     
     
         11 . A photosemiconductor device comprising a photosemiconductor element encapsulated with the epoxy resin composition for photosemiconductor encapsulation as set forth in  claim 10 .  
     
     
         12 . An ultraviolet rays-curable can-coating composition comprising: 
 10 to 100 parts by weight of an alicyclic epoxy compound (A) represented by the following formula (I):                           (wherein X represents a divalent group selected from oxygen atom, sulfur atom, —SO—, —SO 2 —, —CH 2 —, —C(CH 3 ) 2 —, —CBr 2 —, —C(CBr 3 ) 2 —, —C(CF 3 ) 2 —, —C(CCl 3 ) 2 — and —CH(C 6 H 5 )—, or a single bond linking two alicyclic rings; and R 1  to R 18  are the same or different and each represents one of hydrogen atom, halogen atom, a hydrocarbon group which may contain oxygen atom or halogen atom, and an alkoxyl group which may have substituent groups);    0 to 90 parts by weight of a compound having an alicyclic epoxy group in the molecule and also having an ester linkage and/or an epoxy compound (B) having a glycidyl group;    1 to 50 parts by weight of a copolymer (F) having at least one glycidyl group and/or alicyclic epoxy group, with respect to 100 parts by weight of the total amount of the alicyclic epoxy compound (A) and the epoxy compound (B); and    0.01 to 20 parts by weight of a cationic polymerization initiator (G) which generates cation by ultraviolet irradiation.    
     
     
         13 . The ultraviolet rays-curable can-coating composition according to  claim 12 , wherein the copolymer (F) is a copolymer of glycidyl group-containing polymerizable unsaturated monomer and/or alicyclic epoxy group-containing polymerizable unsaturated monomer, and other polymerizable monomer.  
     
     
         14 . The ultraviolet rays-curable can-coating composition according to  claim 12  or  13 , which further contains a lubricity-imparting agent in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the alicyclic epoxy compound (A) and the epoxy compound (B).  
     
     
         15 . The ultraviolet rays-curable can-coating composition according to any one of  claims 12  to  14 , which further contains resin fine particles in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the total amount of the alicyclic epoxy compound (A) and the epoxy compound (B).  
     
     
         16 . The ultraviolet rays-curable can-coating composition according to any one of  claims 12  to  15 , wherein the alicyclic epoxy compound (A) represented by the formula (I) is an epoxy compound produced by using an aliphatic percarboxylic acid having water content of 2% by weight or less.  
     
     
         17 . A process of producing a coated metal can, which comprises applying the ultraviolet rays-curable can-coating composition as set forth in any one of  claims 12  to  16  to a metal plate, a resin film-laminated metal plate or a metal can molded from those metal plates, and irradiating the coated product with ultraviolet rays to cure the resulting coating film.