GB1427768A - Prevention of scattering of glass fragments from burst glass containers - Google Patents

Abstract

1427768 Polyurethane coated glass containers TOYO INK MFG CO LTD 17 Dec 1973 [23 Dec 1972] 58423/73 Heading B2E [Also in Division C3] A process for preventing scattering of glass fragments from a burst glass container comprises: coating the surface of the container to at least 100Á thickness with a composition comprising a dispersion of (A) one equivalent of a powder, of particle diameter 1 to 100Á, of a solid with a melting point of more than 20‹C in (B) 0.9 to 1.5 equivalents of a liquid urethane prepolymer having at least two NCO groups and a M.W. of at least 400 per NCO group, the compound (A) being capable of reacting with the prepolymer to form a higher M.W. compound; and heating the coated glass container to cure the coating and form a film having a tensile strength of at least 300 kg/cm<SP>2</SP> and a percentage elongation at break of 200%. The urethane prepolymer may be transparent and the reaction product of one equivalent of a polyol with M.W. of 250 to 1500 per hydroxy group, e.g. polypropylene glycol, polyethylene glycol adipate, polybutylene glycol adipate, polytetramethylene glycol, a polyester-polyol, 2, 2, 4-trimethyl-1, 3-pentanediol, trimethylol propane, 1, 4-butylene glycol or trimethylhexanediol with two equivalents of a diisocyanate having M.W. of 90 to 130 per NCO group e.g. tolylene isophorone, hexamethylene, xylylene, 4, 4'-diphenylmethane, or naphthalene diisocyanate. The solid chain extender (A) may be melamine, benzoguanamine, acetoguanamine, dicyandiamide, an aromatic amine (mp>50‹C), a polyamine, trimethylol ethane, bisphenol A, an epoxy intermediate, pentaerythritol, trimethylol propane, or an acrylic or vinyl polymer having a functional group such as -OH, -NH 2 or -CO 2 H. The composition may be cured by heating from 180-200‹C for 10 minutes. Preferably equimolar amounts of powder and prepolymer are used.