Patent GB-557230-A (GB)
Title: Improved cork compositions
IPC: C08L97/00
Filed: 1941-09-09
Abstract: 557,230. Cork compositions. DU PONT DE NEMOURS & CO., E. I. Sept. 9, 1941; No. 11526. Convention date, Sept. 9, 1940. [Class 2 (iii)] A cork composition suitable for use as a floor covering and for gaskets, closures, shoe insoles, counters, spinning cots, heat insulating and acoustic tiles, polishing wheels, printers blankets, vibration dampers, knife handles and fishing rod handles comprises finely divided cork combined or mixed with a high molecular weight synthetic polyamide, an interpolyamide or a polyester-amide. Polyester-amides are obtained from diamines, dibasic acids and glycols, from dibasic acids, glycols and aminoalcohols, and from aminoacids, dibasic acids and glycols, the low molecular weight polyesteramide produced being converted by a diisocyanate or diisothiocyanate into a high molecular weight product. The composition may be modified by the addition of plasticizers, softening agents, other resins, pigments, antioxidants, fillers, extenders, anti-tack agents and fungicides. Specified additions are : plasticizers, toluenesulphonamides and other sulphonamides, phenols specifically resorcinol and esters and ethers ; softening agentsglycerol ethylene and propylene glycols, mannitol and sorbitol ; waxes-paraffin, carnauba. beeswax, Asiatic, montan and hydrogenated castor oil ; anti-tack agents.-castor oil, olive and stearic acids ; resins rosin, hydrogenated rosin, ester gum, shellac, gum kauri, copal and phenol-formaldehyde resins obtained from p-hydroxydiphenyl, p-tert, butyl phenol, p-tert, amyl phenol or o-cyclohexylphenol ; fillers and extenders-wood flour, chalk, clay, whiting vermiculite, mica, leather dust, asbestos and silica, and pigments.-zinc oxide, carbon black, lakes, azo pigments, Prussian blue, chrome green, titanium oxide, iron oxide, Lithol red, lithopone, zinc sulphide, antimony sulphide, iron blue and the phthalocyanines. The polyamide binder may be combined or mixed with the cork by coating the particles with a solution, milling the materials on a rubber mill, softening the polyamide by heat or a small amount of solvent or both and mixing with the cork in a mixer. The amount of polyamide is 5-80 per cent., preferably 10 to 60 per cent. of the weight of the finished composition. In examples (1) an interpolyamide obtained from hexamethylene diammonium adipate, # -aminocapronitrile, water and acetic acid is blended with a non-thermosetting p-hydroxydiphenylformaldehyde resin, glycerol and cork granules. The resins are applied to the cork in the form of solutions in ethanol and benzene respectively, and the coated cork is converted into a cake for sheeting by hot pressing ;(2) A soft wax obtained by reacting ethylene glycol, ethanolamine, adipic acid and water is reacted with hexamethylene diisocyanate. Equal parts of the product and cork are mixed on rolls and hot moulded to give a soft, resilient product. The wax may be (3) mixed with the cork moistened with chloroform before the reaction with diisocyanate ; or (4) the mixture may also contain lithopone and red iron oxide ; (5) A wax is obtained by reacting hexamethylenediammonium adipate, adipic acid, ethylene glycol and water and is converted into a polyester-amide by heating with hexamethylene diisocyanate. The product is dissolved in a mixture of chloroform and methanol and added to cork flour with wood flour, lithopone and brown iron oxide, and after mixing in a screwgrinder is dried and pressed ; (6) An interpolyamide prepared from hexamethylene diammonium adipate and decamethylene sebacate is dissolved in formic acid, the solution mixed with shredded cork and the mixture hotpressed. Specifications 461,236, 461,237, 545,940 and U.S.A. Specification 2,071,250 are referred to.