Patent GB-1470087-A (GB)
Title: Organic flatting agents and method of preparation
IPC: C08G8/08
Filed: 1974-04-02
Abstract: 1470087 Urea and/or phenol-formaldehyde resin beads PPG INDUSTRIES Inc 2 April 1974 [3 April 1973] 14509/74 Heading C3R A method of preparing solid inert particulate beads comprising a fully polymerized urea and/ or phenol-formaldehyde resin comprises (A) reacting urea or phenol or a substituted urea or phenol or any mixture thereof and formaldehyde in an alkaline aqueous or organic medium to form a water-soluble prepolymer; (B) if necessary, blending the reactants or the resulting prepolymer with a hydroxyfunctional protective colloid-forming material; (C) (1) polymerizing the prepolymer by acidifying the mixture thus formed under agitation, thereby forming particulate beads, then (2) agglomerating said beads to a desired gross particle size; and (D) collecting the said beads. In a modification the beads are prepared by (A) acidifying while under agitation in an aqueous or organic medium a watersoluble prepolymer of urea or phenol or a substituted urea or phenol or any mixture thereof and HCHO, if necessary in the presence of a hydroxy-functional protective colloid; (B) polymerizing the mixture under agitation, and then agglomerating and collecting the resultant beads. The beads may be collected in slurry form or they may be dried. The protective colloid may be charged initially with the reactants in the prepolymer process. When the beads are prepared from urea and formaldehyde a protective colloid is preferably used. Suitable ureas are urea, monomethylol urea, methylene urea, thiourea, ethyleneurea, N,N<SP>1</SP> - dimethylol ethyleneurea, acetylurea, malonylurea and N,N<SP>1</SP>-diethylurea. Suitable phenols are phenol, p-alkyl, p-aryl- and p-halophenols. Suitable protective colloids are polyoxyethylene alkylphenols; esters of glycols, glycerol, polyglycerol, erythritol, polyoxyalkylene polyols, hexitols, sorbitan, sucrose, polyoxyethylene sorbitan and polyoxyalkylene sucrose; methyl glucoside esters; polyvinyl alcohol and "Carbowax" (Registered Trade Mark). The beads generally have a size from less than 1 micron up to 50 microns, and can be used as flatting agents in film-forming coating compositions. Suitable film-forming materials are acrylic resins, cellulose derivatives, polyolefin resins, polyamide resins, alkyd resins and phenolic resins. In Examples I-V beads are prepared either (1) by preparing a prepolymer from urea and HCHO using triethanolamine as catalyst, then adding either (i) polyvinyl alcohol and then water and sulphuric acid or (ii) water and citric acid, and further polymerizing whilst stirring; or (2) by preparing a phenol-HCHO prepolymer in the presence of aqueous NaOH then adding water, polyvinyl alcohol and benzyl chloride and further reacting, then adding H 2 SO 4  whilst under high shear agitation. In Examples VI to X urea-HCHO beads were added to coating compositions comprising a linseed alkyd resin modified with toluene diisocyanate, mineral spirits, "Bentone" (Registered Trade Mark), ethanol, phenyl mercuric oleate, lead tallate, manganese tallate and cobalt tallate driers and an antiskinning agent, and optionally a silica aerogel extender. In Examples XI urea-HCHO beads are added to a pigment paste comprising an alkyd resin as above, lacquer solvent, cobalt drier, carbon black, suspending agent and mineral spirits which is then added to a coating composition comprising the above alkyd resin, zirconium drier, manganese- and cobalt-tallate driers, antiskinning agent and mineral spirits.