Molding material for plastic lens

Abstract

A molding material for plastic lenses, comprising a hydrogenated product of an aromatic vinyl polymer, wherein the hydrogenated product of the aromatic vinyl polymer has properties that the hydrogenation rate of aromatic rings is at least 97%, the weight average molecular weight (Mw) is within a range of 50,000 to 500,000, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is at most 2.5, a plastic lens obtained by molding the molding material, novel hydrogenated products of aromatic vinyl polymers, which are suitable for use as molding materials, and a production process thereof.

1 . A molding material for plastic lenses, comprising a hydrogenated product of an aromatic vinyl polymer, wherein the hydrogenated product of the aromatic vinyl polymer has the following properties: 
 (1) the hydrogenation rate of aromatic rings being at least 97%;    (2) the weight average molecular weight (Mw) being within a range of 50,000 to 500,000; and    (3) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 2.5.    
     
     
         2 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer has the following properties: 
 (1) the hydrogenation rate of aromatic rings being at least 98%;    (2) the weight average molecular weight (Mw)-being within a range of 90,000 to 300,000; and    (3) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 2.3.    
     
     
         3 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer has the following properties: 
 (1) the hydrogenation rate of aromatic rings being 99 to 100%;    (2) the weight average molecular weight (Mw) being within a range of 100,000 to 300,000; and    (3) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 2.0.    
     
     
         4 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer has a weight average molecular weight (Mw) within a range of 100,000 to 250,000.  
     
     
         5 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer has a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of at most 1.9.  
     
     
         6 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer has a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of at most 1.8.  
     
     
         7 . The molding material for plastic lenses according to  claim 1 , wherein the hydrogenated product of the aromatic vinyl polymer is a hydrogenated product of polystyrene.  
     
     
         8 . A plastic lens obtained by molding the molding material for plastic lenses according to any one of claims  1  to 7.  
     
     
         9 . A hydrogenated product of an aromatic vinyl polymer, obtained by hydrogenating the aromatic vinyl polymer, wherein the hydrogenated product of the aromatic vinyl polymer has the following properties: 
 (a) the hydrogenation rate of aromatic rings being at least 97%;    (b) the weight average molecular weight (Mw) being within a range of 100,000 to 300,000; and    (c) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 2.0.    
     
     
         10 . The hydrogenated product of the aromatic vinyl polymer according to  claim 9 , which has the following properties: 
 (a) the hydrogenation rate of aromatic rings being at least 98%;    (b) the weight average molecular weight (Mw) being within a range of 100,000 to 250,000; and    (c) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 1.9.    
     
     
         11 . The hydrogenated product of the aromatic vinyl polymer according to  claim 9 , which has the following properties: 
 (a) the hydrogenation rate of aromatic rings being 99 to 100%;    (b) the weight average molecular weight (Mw) being within a range of 140,000 to 230,000; and    (c) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 1.8.    
     
     
         12 . A process for producing a hydrogenated product of an aromatic vinyl polymer by hydrogenating an aromatic vinyl polymer obtained by polymerizing an aromatic vinyl compound, the process comprising polymerizing the aromatic vinyl compound to synthesize an aromatic vinyl polymer having a weight average molecular weight (Mw) within a range of 100,000 to 400,000 and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to a number average molecular weight (Mn) of at most 2.0 and then subjecting the aromatic vinyl polymer to a hydrogenation reaction in the presence of a hydrogenation catalyst to obtain a hydrogenated product having the following properties: 
 (a) the hydrogenation rate of aromatic rings being at least 97%;    (b) the weight average molecular weight (Mw) being within a range of 100,000 to 300,000; and    (c) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) being at most 2.0.    
     
     
         13 . The production process according to  claim 12 , wherein the aromatic vinyl polymer is synthesized by solution-polymerizing the aromatic vinyl compound using an organic alkali metal as an initiator in a hydrocarbon solvent.  
     
     
         14 . The production process according to  claim 13 , wherein the aromatic vinyl compound is solution-polymerized in the presence of a Lewis base.