| 摘要 |
<p>An epoxy resin which is a polyether derivative of a polyhydric phenol, has terminal epoxide groups, and has an epoxy equivalent below 400 is modified by pentaerythritol in proportions such that there are at least 2 epoxy groups for each hydroxyl group of the pentaerythritol, the modified resin having an epoxy equivalent not in excess of 850, and a hydroxyl equivalent not in excess of 240, and in which an average of at least three of the hydroxyl groups of the pentaerythritol have condensed with epoxy resin molecules. The temperature of reaction is 180-230 DEG C. for at least 5 hours. The epoxy resins discussed are all bisphenol A-epichlorhydrin condensates. The resins are used for coating (see Division B2), the following additives being specified: hardeners; polyamines or their adducts with epoxy resins, polyamides, and polyisocyanates, e.g. tolylene diisocyanate, which may be phenol-stopped; solvents; xylol, butanol, ethyl acetate, "Cellosolve" (Registered Trade Mark), and Cellosolve acetate; pigment; TiO2.ALSO:A variety of substrates, steel and glass being used in the examples, and copper, tin, brass, aluminium, glazed tiles, hardboard and phenolic laminates being listed, may be coated with epoxy resins modified with pentaerythritol (see Division C3). The epoxy resins disclosed are all bisphenol A-epichlorhydrin condensates. The following additives are also specified:-hardeners: polyamines or their adducts with epoxy resins, polyamides, and polyisocyanates, e.g. tolylene diisocyanate, which may be phenolstopped; solvents: xylol, butanol, ethyl acetate, "Cellosolve" (Registered Trade Mark) and "Cellosolve" acetate; pigment: TiO2. The coatings are either air-dried or heated at 100-150 DEG C. for 30-60 minutes; they may then be exposed to an atmosphere of controlled humidity.</p> |
