Patent GB-742011-A (GB)
Title: Improvements in or relating to unitary thermally insulating members
Inventor: CUNNINGHAM MARVIN HOUSTON
IPC: F25D21/14
Filed: 1953-04-28
Abstract: <PICT:0742011/III/1> <PICT:0742011/III/2> <PICT:0742011/III/3> A unitary heat insulating member, e.g. a refrigerator or part thereof, is made by uniting a mass of fibres with a small quantity of binder, shaping the mass into a body having substantially the desired shape and size, impregnating the entire exterior of the body with an organic resin to a depth of the order of 0.125 to 0.25 inch, curing and hardening the applied resin so as to form a base member having a rough surface, and applying at least one surface coating of an organic resin.  The member may include metal or plastic reinforcing members, only attachment parts of which protrude e.g. door hinges. The protruding parts are coated with a silicone oil or a polyvinyl acetate composition prior to application of the resin so that they can be stripped easily.  The fibres may include one or more of glass fibres, rock wool, mineral wool, asbestos fibres, synthetic, e.g. Nylon, fibres, or balsam wool fibres.  The binder may be a phenolic resin of a vinyl polymer.  The organic resin may be a cellulose ester or ether, a phenolic resin, a polyepoxy resin, an urea-formaldehyde or urea-formaldehyde-butanol resin, a melamine formaldehyde resin, an alkyd resin or an oil modified derivative thereof, or a vinyl polymer.  It may be applied as an organosol with a suitable solvent or dispersant.  It may include mineral or other pigments, dyes and fillers.  The impregnating resin may be applied by spraying, dipping or flushing and the coating resin by spraying, dipping or brushing. To form a refrigerator, Fig. 1, a steel frame 40 has attached thereto by tying, wiring or adhesive batts of the fibrous insulating material 30.  It is then sprayed with an organosol comprising a plasticizer, vinyl chloride-vinyl acetate copolymer, and a dispersant comprising diisobutyl and xylene to form the impregnating layer 34 which is then cured.  Projecting fibres &c. are then removed by sanding or filing and any cavities are filled by spotting with the resin.  A primer coat is then applied comprising a linseed oil modified glycerol phthalate resin, whiting mica dust, vinyl chloride-vinyl acetate copolymer and a solvent.  This coat is then part-cured, sanded and cured. It may then be spotted or another coat applied, part-cured, sanded and cured.  The finish coat is then applied and comprises titanium dioxide, a solvent and either polyvinyl resin, or melamine resin and alkyd resin, or urea-formaldehyde resin and glycerol phthalate resin. The surface layer is denoted by 36.  The door 14 a spring-loaded door 18 for the ice-making compartment and drip tray 20 are similarly formed, the latter sliding on runners 106 fixed to the cabinet or to the evaporator 16.  Runners 106 have drip strips 107. Sealing gaskets 112, 138 and 148 are provided. The rear wall has a gutter 104 for defrost water supplied through an aperture (not shown), in the drip tray 20.  The members may also be moulded in dies, the moulding of a refrigerator door 14 being shown in Figs. 8 and 11.  A formed body 114 of fibres is coated with an impregnating resin 140 and then this layer is cured in a heated mould 180, 184. The resulting body may then receive another thin coating which is cured in the mould.  A primer coating of resin is then applied and this is cured in an oven. The body is then put in a mould 206, 210 and resin to form the surface coating is forced in by an injection nozzle 214, air being withdrawn through a vent 216.  Alternatively, a quantity of resin may be placed in this mould and made to flow round the shaped body by the mould pressure.  Instead of applying pressure to the mould parts, an air tube may extend into the fibres of the body and, when the mould is closed, an air pressure of ten pounds per square inch is applied through this tube to the interior of the body. A final coat of enamel may be applied.  The intermediate step of applying a primer coating and curing it in an oven may be omitted.