Patent GB-577835-A (GB)
Title: Improvements in or relating to containers for liquid fuels
IPC: B64D37/06
Filed: 1943-05-06
Abstract: 577,835. Coated compound sheet material. DUERDEN, A., SHAKESBY, L., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. May 6, 1943, No. 7213. [Class 140] [Also in Group XXIX] Flexible sheet material suitable for use as the fuel retaining wall in a petrol tank comprises two or more layers of fabric or other porous sheet material bonded together with an interlayer or interlayers of a petrol-resistant composition which is either a plasticized cellulose derivative (nitrate or acetate) or a rubber-like polymer based on butadiene, e.g., neoprene, or a rubber-like polymer based on ethylene polysulphide, e.g., " Thiokol" Registered Trade Mark, and coated on both sides with a plasticized polyvinyl acetal composition, e.g., as described in Specification 575,477. The polyvinyl acetal may be obtained by partial or complete hydrolysis of polyvinyl acetate or other polyvinyl ester and simultaneous or subsequent partial or complete condensation with the appropriate aldehyde (formaldehyde, acetaldehyde, or butyraldehyde) to give an acetal which may contain residual ester and/or hydroxy groups. Two or three layers of fabric may be bonded together. The coating composition may comprise a polyvinyl acetal resin and a resinous ester of a polyhydric alcohol with a saturated aliphatic polybasic acid containing from 4 to 10 carbon atoms or a polyvinyl acetal resin with a plasticizer such as the phthalic ester of glycol monoethyl ether. The solvent for the coating composition may be methyl cyclohexanone, a mixture of methyl cyclohexanone with methyl or other lower aliphatic alcohol, or a mixture of two or more of the solvents acetone, trichlorethylene, benzene, methyl alcohol, and ethyl alcohol, which mixtures may also include methyl cyclohexanone. A polyvinyl acetal cold-curing cement may be employed in the manufacture of fuel containers from the flexible sheet material. In an example, two equal lengths of mercerized cotton sheeting are each coated with a composition comprising Thiokol F (Registered Trade, Mark) zinc oxide, soft carbon black, stearic acid, mercaptobenzthiazole disulphide, diphenylguanidine, and dichlorethylene, more of the composition is calendered on to the coated face of one of the sheets and the two lengths are united by passage through pressure rollers with the coated faces in contact, that of the calendered sheet having previously been moistened with dichlorethylene. After heating to remove the solvent and curing, the compound sheet is coated on each face with polyvinyl formal resin, glyceral adipate benzene, industrial methylated spirits, and acetone, a plurality of coats being applied. The material is tailored to shape, assembled, and cemented with the coating composition. The assembled container is provided with a hole permitting the former to be removed .and afterwards forming the aperture for a filler cap. Alternatively, the former may be removed and the jointed portions reinforced by stitching afterwards rendered leakproof by cement. The container may be rendered selfsealing by cementing three successive layers of sponge rubber on to the outer wall, the first being cemented by a polyvinyl formal composition. The self-sealing covering may be applied as a compound material. A layer of cotton fabric is cemented to the outer rubber layer and is coated with polyvinyl formal resin composition. The self-sealing covering may alsocomprise other swellable rubber materials, which may be combined with felt.