Production process and use for transparent heat-resistant resin

Abstract

The present invention provides a production process for a transparent heat-resistant resin, and further, a transparent heat-resistant resin and uses therefor, wherein the production process involves high dealcoholation conversion and a low content of residual volatiles in the resultant resin, and therefore can prevent foam or silver streak from occurring in the molded product, and further, facilitates melt-molding such as injection molding, and is fit for industrial production, and involves good efficiency. The production process for a transparent heat-resistant resin comprises the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer to obtain a transparent resin having the heat resistance, and is characterized in that the dealcoholation reaction is run in the presence of a solvent, and further characterized by further comprising a devolatilization step which is carried out jointly with the dealcoholation reaction.

What is claimed is:  
     
         1 . A production process for a transparent heat-resistant resin, comprising the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer to obtain a transparent resin having the heat resistance, with the production process being characterized in that the dealcoholation reaction is run in the presence of a solvent, and further characterized by further comprising a devolatilization step which is carried out jointly with the dealcoholation reaction.  
     
     
         2 . A production process according to  claim 1 , wherein the devolatilization step is initiated at an interval after the dealcoholation reaction has been initiated.  
     
     
         3 . A production process according to  claim 2 , wherein the conversion of the dealcoholation reaction is not lower than 60 % when the f flization step has been initiated.  
     
     
         4 . A production process according to  claim 1 , wherein the dealcoholation reaction is run with a vessel type reactor.  
     
     
         5 . A production process according to  claim 1 , wherein the dealcoholation reaction is run using an organophosphorus compound as a catalyst.  
     
     
         6 . A production process according to  claim 5 , wherein the organophosphorus compound is at least one member selected from the group consisting of alkyl(aryl)phosphonous acids (which may be their tautomers, namely, alkyl(aryl)phosphinic acids), phosphate diesters or monoesters, phosphate diesters or monoesters, and alkyl(aryl)phosphonic acids.  
     
     
         7 . A transparent heat-resistant resin, which is obtained by a process including the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer, with the transparent heat-resistant resin being characterized by having a dealcoholation conversion of not lower than 90% as determined from a weight loss between 150 and 300° C. in dynamic TG measurement.  
     
     
         8 . A transparent heat-resistant resin, which is obtained by a process including the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer, with the transparent heat-resistant resin being characterized by having a yellowness index (YI) of not more than 6 in a 15 weight % chloroform solution.  
     
     
         9 . A transparent heat-resistant resin, which is obtained by a process including the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer, with the transparent heat-resistant resin being characterized by having a weight-average molecular weight of 40,000˜300,000.  
     
     
         10 . A transparent heat-resistant resin, which is obtained by a process including the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer, with the transparent heat-resistant resin being characterized in that a molded product by injection molding of the transparent heat-resistant resin has a total luminous transmittance of not lower than 85%.  
     
     
         11 . A transparent heat-resistant resin, which is obtained by a process including the step of running a dealcoholation reaction of a polymer having a hydroxyl group and an ester group in its molecular chain to introduce a lactone ring structure into the polymer, with the transparent heat-resistant resin being characterized in that a molded product by injection molding of the transparent heat-resistant resin has a haze value of not higher than 5%.  
     
     
         12 . A transparent heat-resistant resin molding material, comprising the transparent heat-resistant resin as recited in  claim 7 .  
     
     
         13 . A transparent heat-resistant resin molding material, comprising the transparent heat-resistant resin as recited in  claim 8 .  
     
     
         14 . A molded product, which is obtained by a process including the step of molding a transparent heat-resistant resin molding material that includes the transparent heat-resistant resin as recited in  claim 7 .  
     
     
         15 . A molded product, which is obtained by a process including the step of molding a transparent heat-resistant resin molding material that includes the transparent heat-resistant resin as recited in claim  8 .