Patent GB-1339013-A (GB)
Title: Methods of joining sections of thermal insulation board
IPC: B29C44/00
Filed: 1970-02-25
Abstract: 1339013 Thermal insulation J W KITSON 19 April 1971 [25 Feb 1970 21 Dec 1970] 9165/70 and 60650/70 Heading F4H [Also in Division B5] A method of joining sections 1, 3, Fig. 4, of preformed thermal insulation board comprises positioning sections of the board to be joined together with a cavity defined therebetween, and causing a liquid sealing/bonding agent 17 to flow into the cavity and to subsequently harden into a solid body without substantial increase in volume. As described, the method is applied to the making of an insulative cabinet for a refrigerator having side walls 1, 2, Figs, 1 and 2, top and back 3, step 4 a frame 5 and a door 6. The board used for the side walls and top consists of a core 7 of rigid foamed polyurethane or expanded polystyrene between a composite sheet 8 of an inner layer of cardboard and an outer layer of polypropylene film and a sheet 9 of thick paper or cardboard, part of sheet 8 on the side walls being removed to form a cavity 10 for the step 4 and a sheet 16 of expanded polystyrene. The top, back and steps are formed by a board similar to that of. the side walls and folded as shown, the polypropylene film not being cut, and blocks 7 of urethane foam fill the cut corners and are secured thereto by aluminium foil and adhesive. In assembling the cabinet, the side wall 1 is placed on a panel 11 of acrylic coated steel, the folded board 3 is placed on the side wall, a steel plate 14 for supporting a refrigeration unit is placed under the step 4, and the side wall 2 and a further panel 11 placed on the board 3, the assembly then being pressed together by the platens of a jig. The liquid sealing/bonding agent 17, such as urethane plastics material polyester or epoxy resin, is dispensed around a rim of the lower panel to flow into the cavity between the side wall 1 and board 3 which is cut at its edge to have a slight bevel (Fig. 4), the material, which may include a chemical catalyst, hardening into a solid rigid body. After hardening, the assembly is inverted for the sealing/ bonding agent to be supplied to the cavity between the side wall 2 and board 3. A top surface of acrylic coated sheet steel may be fixed by expanded polystyrene spacers to the top of the cabinet. A frame 5 of shallow U- shaped channel of polyvinyl chloride coated sheet steel is secured by the agent 17 to the front of the cabinet, the flanges of the channel being bent so that the liquid sealing/bonding agent forms a mechanical bond between the frame and cabinet. A magnetic gasket may be fitted to the frame for cooperation with the door. In other embodiments, grooves or undercuts are formed in the joints between the side walls 1, 2 and board 3 so that the liquid sealing/bonding agent, in addition to adhering the parts together, forms a mechanical interlock therebetween which may be increased by the use of an angled trim (30, Fig. 8, not shown). In another construction of cabinet, the door frame is replaced by top and bottom rails and plastic facings secured to the cabinet by the liquid sealing/bonding agent which may also be used to secure hinges, brackets &c. to the cabinet.