Novolak molding compounds containing hexamethylenetetramine monometaborate

Abstract

Manufacture of rapidly hardening phenol formaldehyde resin molding compositions having improved thermal stability and good flow characteristics by incorporating into the molding compositions hexamethylenetetramine in the form of a metaboric acid addition product. The resulting molding composition is then rolled and ground to produce the molding composition of improved properties.

I claim: 
     
       1. A process for the manufacture of a phenol formaldehyde resin molding composition capable of rapidly hardening at a molding temperature greater than 120° C. .[.and having good thermal stability and flow characteristics at plasticizing temperatures less than 120° C.,.]. comprising intimately blending .Iadd.at a temperature below 120° C. .Iaddend.100 parts by weight of a phenol formaldehyde resin molding composition with 12 to 19 parts .Iadd.hexamethylenetetramine .Iaddend.by weight .[.of.]. .Iadd.as .Iaddend.hexamethylenetetramine monometaborate, rolling said blend and grinding the sheet produced by said rolling .Iadd.into a powder.Iaddend.. .[.2. A process comprising: (1) preparing an addition product of hexamethylenetetramine monometaborate by reacting hexamethylenetetramine and metaboric acid in a molar ratio of 1:1;   (2) blending at a blending temperature less than 120° C., an effective amount of said addition product sufficient to accelerate hardening at temperatures greater than 120° C. with a substantially greater amount of novolak phenol formaldehyde resin molding composition free of hexamethylenetetramine added as such, the resulting blend exhibiting good thermal stability and flow characteristics at plasticizing temperatures less than 120° C., and   (3) subsequently producing a molded article under pressure from said resulting blend at a molding temperature greater than 120° C..].   
     
     
           The process of claim .[.2.]. .Iadd.5 .Iaddend.wherein said blending is carried out at temperatures .[.greater than.]. .Iadd.between .Iaddend.70° C. .Iadd.and 110° C. .Iaddend.and the blend is 
     
     
        cooled and ground to produce a molding powder. 4. The process of claim .[.2.]. .Iadd.5 .Iaddend.wherein said molded article is produced by .Iadd.screw .Iaddend.injection molding .[.with screw propulsion.].. .Iadd. 5. A process according to claim 1 wherein a molded article is subsequently produced under pressure from the ground material obtained from grinding said sheet which molded article is produced at a temperature greater than 120° C..Iaddend.