Granular Polymer Additives and Their Preparation

Abstract

A compacted particulate polymer additive composition in a dry granular form formed from a substantially uniform mixture of the following components: (a) at least one particulate sterically-hindered phenolic compound; and (b) one or more particulate polymer additives other than a sterically-hindered phenolic compound; wherein the particles of said composition are held together in compacted dry granular form exclusively or substantially exclusively by contact with dried surfaces of in situ desolvated particles from particles of one or more at least partially solvated components of (a), and optionally by contact with dried surfaces of in situ desolvated particles from particles of one or more at least partially solvated components of (b). Compositions of this type except that there is no component (b) are also described.

1 . A compacted particulate polymer additive composition in a dry granular form formed exclusively from at least one sterically-hindered phenolic compound, wherein the particles of said composition are held interbonded one to another in compacted dry granular form exclusively or substantially exclusively by interbonding with in situ desolvated surfaces of particles of at least partially solvated particles of at least one sterically-hindered phenolic compound used in forming said composition. 
   
   
       2 . A composition of  claim 1  wherein said at least one sterically-hindered phenolic compound contains at least one hydroxyphenyl moiety in which at least one of the ortho-positions relative to the hydroxyl group is substituted by a tertiary alkyl group. 
   
   
       3 . A composition of  claim 1  wherein said at least one sterically-hindered phenolic compound is 1,3,S-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene. 
   
   
       4 . A composition of  claim 1  wherein said at least one sterically-hindered phenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate. 
   
   
       5 . A process of producing a compacted particulate polymer additive composition in a dry granular form, which process comprises:
 1) forming a paste exclusively from (A) at least one sterically-hindered phenolic compound and (B) an inert organic processing solvent that can be vaporized at a temperature below the lowest melting point or initial melting temperature of said one or more components of (A);   2) compressing and shaping the paste while preventing or substantially preventing melting of solids used in forming the paste, to produce a wet compacted composition in granular form; and   3) drying said wet compacted composition in granular form by vaporizing said processing solvent therefrom to form the dried compacted particulate polymer additive composition in a granular form.   
   
   
       6 . A process of  claim 5  wherein said at least one sterically-hindered phenolic compound contains at least one hydroxyphenyl moiety in which at least one of the orthopositions relative to the hydroxyl group is substituted by a tertiary alkyl group. 
   
   
       7 . A process of  claim 5  wherein said at least one sterically-hindered phenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene. 
   
   
       8 . A process of  claim 5  wherein said at least one sterically-hindered phenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate. 
   
   
       9 . A compacted particulate polymer additive composition in a dry granular form, wherein said composition is formed by a process which comprises:
 1) forming a paste exclusively from (A) at least one sterically-hindered phenolic compound and (B) an inert organic processing solvent that can be vaporized at a temperature below the lowest melting point or initial melting temperature of said one or more components of (A);   2) compressing and shaping the paste while preventing or substantially preventing melting of solids used in forming the paste, to produce a wet compacted composition in granular form; and   3) drying said wet compacted composition in granular form by vaporizing said processing solvent therefrom to form the dried compacted particulate polymer additive composition in a granular form;   
     said additive composition having compressive hardness and physical integrity resulting from the particles in said granules being held interbonded one to another in compacted dry granular form exclusively or substantially exclusively by interbonding among in situ desolvated surfaces of at least one sterically-hindered phenolic compound used in forming said composition. 
   
   
       10 . A composition of  claim 9  wherein said at least one sterically-hindered phenolic compound contains at least one hydroxyphenyl moiety in which at least one of the ortho-positions relative to the hydroxyl group is substituted by a tertiary alkyl group. 
   
   
       11 . A composition of  claim 9  wherein said at least one sterically-hindered phenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene. 
   
   
       12 . A composition of  claim 9  wherein said at least one sterically-hindered phenolic compound is 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate.