Sterically hindered phenol antioxidant granules having balanced hardness

Abstract

Sterically hindered phenol antioxidant additive granules are formed from a paste comprising an organic processing agent comprising a friability reduction agent. The friability reduction agent preferably is an alcohol, more preferably an alkanol having up to about 8 carbon atoms, most preferably methanol, ethanol, and/or isopranol. After drying, the granules consist essentially of the sterically hindered phenol antioxidant additive system. The granules have a balanced hardness that provides sufficient abrasion resistance while permitting ready dispersion into a polymer host.

1 . A compound comprising a powder comprising an additive system comprising at least one sterically hindered phenol antioxidant; and, an organic processing agent comprising at least one friability reduction agent.  
     
     
         2 . The compound of  claim 1 , wherein said friability reduction agent is an alcohol.  
     
     
         3 . The compound of  claim 2 , wherein said alcohol comprises a composition of the formula ROH wherein R is an alkyl group of from 1 to 8 carbon atoms.  
     
     
         4 . The compound of  claim 2 , wherein said alcohol is selected from the group consisting of methanol, ethanol, isopropanol, and a combination thereof.  
     
     
         5 . The compound of  claim 2 , wherein said alcohol comprises methanol and said organic processing agent further comprises methylethylketone.  
     
     
         6 . A compound consisting essentially of one or more dried granules consisting essentially of an additive system comprising at least one primarily crystalline sterically hindered phenol.  
     
     
         7 . The compound of  claim 6  wherein said dried granules comprise pellets comprising a balanced hardness of at least about 5 lb/in.  
     
     
         8 . The compound of  claim 7  wherein said pellets comprise at least about 1 wt. % of an essentially amorphous phase comprising said sterically hindered phenol.  
     
     
         9 . The compound of  claim 7  wherein said pellets comprise from about 1 wt. % to about 5 wt. % of said essentially amorphous phase comprising said sterically hindered phenol.  
     
     
         10 . The compound of  claim 7  wherein said balanced hardness is from about 10 lb/in to about 27 lb/in., based on measurements made using 3 mm diameter pellets.  
     
     
         11 . The compound of  claim 9  wherein said balanced hardness is from about 10 lb/in to about 27 lb/in., based on measurements made using 3 mm diameter pellets.  
     
     
         12 . The compound of  claim 7  wherein said balanced hardness is of from about 15 lb/in to about 25 lb/in., based on measurements made using 3 mm diameter pellets.  
     
     
         13 . The compound of  claim 9  wherein said balanced hardness is of from about 15 lb/in to about 25 lb/in., based on measurements made using 3 mm diameter pellets.  
     
     
         14 . The compound of  claim 1  wherein said at least one sterically hindered phenol antioxidant has a melting point of from about 50° C. or greater.  
     
     
         15 . The compound of  claim 6  wherein said at least one sterically hindered phenol antioxidant has a melting point of from about 50° C. or greater.  
     
     
         16 . The compound of  claim 1  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         17 . The compound of  claim 2  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         18 . The compound of  claim 3  wherein said sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         19 . The compound of  claim 4  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         20 . The compound of  claim 6  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         21 . The compound of  claim 7  wherein said sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         22 . The compound of  claim 8  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         23 . The compound of  claim 9  wherein said at least one sterically hindered phenol has a melting point of from about 95° C. or greater.  
     
     
         24 . The compound of  claim 7  wherein said pellets comprise a loose bulk density of from about 400 g/l or greater, a Hosogawa Flowability of about 70 or greater, an average diameter (x) of from about 2 millimeters to about 6 millimeters, and an average length of from about 1.5× to about 3×.  
     
     
         25 . The compound of  claim 8  comprising pellets comprising a loose bulk density of from about 400 g/l or greater, a Hosogawa Flowability of about 70 or greater, an average diameter (x) of from about 2 millimeters to about 6 millimeters, and an average length of from about 1.5× to about 3×.  
     
     
         26 . The compound of  claim 9  comprising pellets comprising a loose bulk density of from about 400 g/l or greater, a Hosogawa Flowability of about 70 or greater, an average diameter (x) of from about 2 millimeter to about 6 millimeters, and an average length of from about 1.5× to about 3×.  
     
     
         27 . The compound of  claim 6  comprising agglomerates comprising a loose bulk density of from about 400 g/l or greater and a Hosagawa Flowability of about 70 or greater.  
     
     
         28 . The compound of  claim 1 , wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate;    tetrakis [methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)]methane;    1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; and    1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H, 3H, 5H) -trione.    
     
     
         29 . The compound of  claim 6 , wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate;    tetrakis [methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)]methane;    1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; and    1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H, 3H, 5H) -trione.    
     
     
         30 . The compound of  claim 1 , wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene; and    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.    
     
     
         31 . The compound of  claim 6 , wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene; and    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.    
     
     
         32 . A compound comprising one or more dried granules made by a process comprising: 
 mixing an organic processing agent comprising a friability reduction agent with a powder comprising an additive system comprising at least a first sterically hindered phenol antioxidant under conditions that are effective to form a paste;    processing said paste to form said one or more granules; and    exposing said one or more granules to conditions that are effective to remove said organic processing agent from said one or more granules but ineffective to melt said sterically hindered phenol antioxidant.    
     
     
         33 . The compound of  claim 32  wherein said friability reduction agent comprises an alcohol.  
     
     
         34 . The compound of  claim 33 , wherein said alcohol comprises a composition of the formula ROH wherein R is an alkyl group of from 1 to 8 carbon atoms.  
     
     
         35 . The compound of  claim 32 , wherein said alcohol is selected from the group consisting of methanol, ethanol, and isopropanol.  
     
     
         36 . One or more granules consisting essentially of at least one primarily crystalline sterically hindered phenol antioxidant having a melting point of from about 50° C. or greater.  
     
     
         37 . One or more granules consisting essentially of at least one primarily crystalline sterically hindered phenol antioxidant having a melting point of from about 95° C. or greater.  
     
     
         38 . The granules of  claim 36  comprising at least 20 wt. % of said at least one sterically hindered phenol antioxidant.  
     
     
         39 . The granules of  claim 37  comprising at least 20 wt. % of said at least one sterically hindered phenol antioxidant.  
     
     
         40 . The granules of  claim 36  having a balanced hardness.  
     
     
         41 . The granules of  claim 37  having a balanced hardness.  
     
     
         42 . The granules of  claim 38  having a balanced hardness.  
     
     
         43 . The granules of  claim 39  having a balanced hardness.  
     
     
         44 . The granules of  claim 42  comprising a loose bulk density of from about 400 g/l or greater, an average diameter (x) of from about 1 millimeters to about 10 millimeters, and, where the granules are pellets, an aspect ratio of from about 1 to about 5.  
     
     
         45 . The granules of  claim 43  comprising a loose bulk density of from about 400 g/l or greater, an average diameter (x) of from about 1 millimeters to about 10 millimeters, and, where the granules are pellets, an aspect ratio of from about 1 to about 5.  
     
     
         46 . The granules of  claim 44  wherein said length is from about 1 to about 5 millimeters.  
     
     
         47 . The granules of  claim 45  wherein said length is from about 1 to about 5 millimeters.  
     
     
         48 . The granules of  claim 43  wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate;    tetrakis [methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)] methane;    1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; 
 1,3,5-tris-(4,4-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H, 3H, 5H)— trione; and  
   thiodiethylenebis-(3,5-di-t-butyl-4-hydroxy) hydrocinnamate.    
     
     
         49 . The granules of  claim 43  wherein said sterically hindered phenol antioxidant is selected from the group consisting of: 
 tetrakis [methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)] methane;    1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;    1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; 
 1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione; and  
   thiodiethylenebis-(3,5,-di-t-butyl-4-hydroxy) hydrocinnamate.    
     
     
         50 . The granules of  claim 43  wherein said sterically hindered phenol antioxidant is 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene.  
     
     
         51 . The granules of  claim 36  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         52 . The granules of  claim 37  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         53 . The granules of  claim 38  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         54 . The granules of  claim 39  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         55 . The granules of any of claims  42  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         56 . The granules of any of claims  43  wherein said at least one antioxidant comprises from about 0 to about 80 wt. % of a secondary phosphite antioxidant.  
     
     
         57 . The granules of  claim 36  wherein said additive system comprises at least about 20 wt. % of said at least one sterically hindered phenol antioxidant, and further comprises a material selected from the group consisting of antistatics, antiblocking agents, flame proofing agents, thioesters, pigments, UV absorbers, and light stabilizers.  
     
     
         58 . The granules of  claim 37  wherein said additive system comprises at least about 20 wt. % of said at least one sterically hindered phenol antioxidant, and further comprises a material selected from the group consisting of antistatics, antiblocking agents, flame proofing agents, thioesters, pigments, UV absorbers, and light stabilizers.  
     
     
         59 . The granules of  claim 51  wherein said additive system comprises at least about 20 wt. % of said at least one sterically hindered phenol antioxidant, and further comprises a material selected from the group consisting of antistatics, antiblocking agents, flame proofing agents, thioesters, pigments, UV absorbers, and light stabilizers.  
     
     
         60 . The granules of  claim 52  wherein said additive system comprises at least about 20 wt. % of said at least one sterically hindered phenol antioxidant, and further comprises a material selected from the group consisting of antistatics, antiblocking agents, flame proofing agents, thioesters, pigments, UV absorbers, and light stabilizers.  
     
     
         61 . The granules of any of  claim 59  further comprising a material selected from the group consisting of an internal lubricant, an external lubricant, an acid neutralizer, and a metal soap.  
     
     
         62 . The granules of any of  claim 60  further comprising a material selected from the group consisting of an internal lubricant, an external lubricant, an acid neutralizer, and a metal soap.  
     
     
         63 . A compound according to  claim 1  substantially as described herein in any of the examples.  
     
     
         64 . A compound according to  claim 6  substantially as described herein in any of the examples.  
     
     
         65 . A process for manufacturing dried granules that are at least in the form of agglomerates or pellets, said granules made by a process comprising: 
 A) mixing (i) an organic processing agent comprising (a) a friability reduction agent or (b) an organic solvent, or (c) both of (a) and (b) with (ii) a powder comprising an additive system comprised of at least a first sterically hindered phenol antioxidant, under conditions that are effective to form a wet paste;    B) processing said wet paste into at least wet agglomerates or wet pellets without melting any solid component(s) in the agglomerates or pellets; and    C) exposing said agglomerates or pellets to conditions that are effective to remove said organic processing agent from said agglomerates or pellets and to dry said agglomerates or pellets but ineffective to melt any solid component of the agglomerates or pellets, to thereby produce dried granules in the form of dried agglomerates or dried pellets.    
     
     
         66 . Dried granules made according to the process of  claim 65.