Granular stabilizer for polymer and production process thereof

Abstract

The present invention provides a granular stabilizer for a polymer which is low-dusting and thus is easy to be handled. The present invention relates to a granular stabilizer for a polymer, comprising a compound shown by the formula (1): wherein R 1 s and R 2 s each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms; R 3 s each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and X represents a single bond, a sulfur atom, an oxygen atom, an alkylidene group having 1 to 8 carbon atoms or a cycloalkylidene group having 5 to 8 carbon atoms.

1 . A granular stabilizer for a polymer, comprising a compound shown by the formula (1): 
     
       
         
         
             
             
         
       
     
     wherein R 1 s and R 2 s each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms; R 3 s each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and X represents a single bond, a sulfur atom, an oxygen atom, an alkylidene group having 1 to 8 carbon atoms or a cycloalkylidene group having 5 to 8 carbon atoms. 
   
   
       2 . The granular stabilizer for a polymer according to  claim 1 , wherein the granular stabilizer for a polymer has a weight of 1 mg to 25 mg per particle, preferably 5 mg to 25 mg per particle. 
   
   
       3 . The granular stabilizer for a polymer according to  claim 1  or  2 , wherein the compound shown by the formula (1) is
 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate or 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate.   
   
   
       4 . The granular stabilizer for a polymer according to  claim 1  or  2 , comprising 99.9 to 80% by weight of the compound shown by the formula (1) and 0.1 to 20% by weight of a compound shown by the formula (2) based on 100% by weight of the granular stabilizer for a polymer, 
     
       
         
         
             
             
         
       
     
     wherein R 1 s and R 2 s each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms; R 3 s each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and X represents a single bond, a sulfur atom, an oxygen atom, an alkylidene group having 1 to 8 carbon atoms or a cycloalkylidene group having 5 to 8 carbon atoms, 
     
       
         
         
             
             
         
       
     
     wherein R 11  is a linear alkyl group having 1 to 30 carbon atoms or a branched alkyl group having 3 to 60 carbon atoms, to the alkyl group may be bonded a hydroxyl group, a carboxyl group, an alkoxycarbonyl group having 2 to 30 carbon atoms, or an alkylcarbonyloxy group having 2 to 30 carbon atoms, and a methylene group contained in the alkyl group, the alkoxycarbonyl group and the alkylcarbonyloxy group may be substituted by a sulfur atom or an oxygen atom; and R 12  is a linear alkyl group having 1 to 30 carbon atoms, a branched alkyl group having 3 to 30 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, to the alkyl group or the aralkyl group may be bonded a hydroxyl group, a carboxyl group, an alkoxycarbonyl group having 2 to 30 carbon atoms or an alkylcarbonyloxy group having 2 to 30 carbon atoms, and methylene groups contained in the alkyl group, the aralkyl group, the alkoxycarbonyl group and the alkylcarbonyloxy group may be substituted by a sulfur atom or an oxygen atom. 
   
   
       5 . The granular stabilizer for a polymer according to  claim 4 , wherein the compound shown by the formula (2) is
 octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, glycerin monostearate, dimyristyl-3,3′-thiodipropionate or distearyl-3,3′-thiodipropionate.   
   
   
       6 . The granular stabilizer for a polymer according to any one of  claims 1  to  5 , wherein the granular stabilizer for a polymer is in the shape of a circular disc, an approximate sphere or an approximate hemi-sphere. 
   
   
       7 . A process for producing a granular stabilizer for a polymer, comprising a compound shown by the formula (1): 
     
       
         
         
             
             
         
       
     
     wherein R 1 s and R 2 s each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms; R 3 s each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and X represents a single bond, a sulfur atom, an oxygen atom, an alkylidene group having 1 to 8 carbon atoms or a cycloalkylidene group having 5 to 8 carbon atoms, wherein the process comprises:
 a first step of melting the compound shown by the formula (1), which has a melting point of T m ° C.; 
 a second step of solidifying the molten material obtained in the first step at a temperature of T 1 ° C. wherein the T 1 ° C. is a temperature lower than T m ° C.; and 
 a third step of heating the solidified material obtained in the second step under an atmosphere at a temperature of T 2 ° C. satisfying the formula (I):
   T 1 <T 2 ≦T m   (I) 
 
 
   
   
       8 . The process for producing a granular stabilizer for a polymer according to  claim 7 , wherein the molten material obtained in the first step is solidified at a temperature of T 1 ° C. satisfying the formula (II):
   5< T   1   <T   m −40  (II)   
     in the second step. 
   
   
       9 . The process for producing a granular stabilizer for a polymer according to  claim 7  or  8 , wherein the molten material obtained in the first step is dropped on a plate to be solidified in the second step. 
   
   
       10 . The process for producing a granular stabilizer for a polymer according to any one of  claims 7  to  9 , wherein the solidified material obtained in the second step is further heated under an atmosphere at a temperature of T 2 ° C. satisfying the formula (III):
     T   m −30 <T   2   ≦T   m   (III)   
     in the third step. 
   
   
       11 . The process for producing a granular stabilizer for a polymer according to any one of  claims 7  to  10 , further comprising a fourth step of cooling the heated material obtained in the third step at a temperature less than T 2 ° C. 
   
   
       12 . The process for producing a granular stabilizer for a polymer according to  claim 11 , wherein the heated material is cooled under an atmosphere at a temperature of T 1 ° C. satisfying the formula (II):
   5< T   1   <T   m −40  (II)   
     in the fourth step. 
   
   
       13 . A process for producing a granular stabilizer for a polymer, comprising a compound shown by the formula (1): 
     
       
         
         
             
             
         
       
     
     wherein R 1 s and R 2 s each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms; R 3 s each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and X represents a single bond, a sulfur atom, an oxygen atom, an alkylidene group having 1 to 8 carbon atoms or a cycloalkylidene group having 5 to 8 carbon atoms, wherein the process comprises:
 a first step of melting the compound shown by the formula (1) having a melting point of T m ° C.; 
 a second step of forming the molten material obtained in the first step at a temperature of T 1 ° C. satisfying the formula (I):
   T 1 <T m   (I) 
 
 
     and
 a third step of mixing the formed material obtained in the second step with the solid compound shown by the formula (1) at a temperature lower than T m ° C. 
 
   
   
       14 . The process for producing a granular stabilizer for a polymer according to  claim 13 , wherein the molten material obtained in the first step is formed at a temperature of T 1 ° C. satisfying the formula (II):
     T   m −50 <T   1   <T   m   (II)   
     in the second step. 
   
   
       15 . The process for producing a granular stabilizer for a polymer according to  claim 13  or  14 , wherein, in the third step, the solid compound shown by the formula (1) is mixed in an amount of 1 to 20% by weight based on 100% by weight of the formed material obtained in the second step. 
   
   
       16 . The process for producing a granular stabilizer for a polymer according to any one of  claims 13  to  15 , further comprising a step of cooling the mixture obtained in the third step at a temperature of T 2  satisfying the formula (III):
   5 <T   2   <T   1 −30  (III).   
   
   
       17 . The process for producing a granular stabilizer for a polymer according to any one of  claims 7  to  16 , wherein the compound shown by the formula (1) is
 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate or 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate.   
   
   
       18 . Use of the granular stabilizer for a polymer according to any one of  claims 1  to  6  for thermally stabilizing a thermoplastic polymer. 
   
   
       19 . A thermoplastic polymer composition, comprising 0.01 to 2 parts by weight of the granular stabilizer for a polymer according to any one of  claims 1  to  6  based on 100 parts by weight of a thermoplastic polymer.