GB416005A - Improvements in or relating to the cementing together of pieces of stock - Google Patents

Abstract

An adhesive for securing together pieces of stock, e.g. shoe soles to uppers, comprises a dissolved cellulose derivative of such a nature, as evidenced by a low viscosity characteristic when in the dissolved state, that it is adapted rapidly to penetrate into the piece of stock to form an anchorage thereto, and a cellulose derivative of such a nature, as evidenced by a higher viscosity characteristic, that it is not adapted to penetrate into the piece of stock to such a degree but is adapted to remain to a greater extent upon the surface. When the cellulose derivatives are nitrocelluloses, the former should have a viscosity characteristic of less than about 4 seconds and the latter of more than about 10 seconds on the scale described in the "Bulletin of the American Society for Testing Materials," 1929, pp. 647-8. In an example, the adhesive comprises two nitrocelluloses of about 12 per cent nitrogen content of the type known as soluble pyroxylin, having viscosities of 1/2 second and 18 seconds respectively, together with denatured ethyl alcohol, ethyl acetate and dibutyl phthalate. If desired, pyroxylins of three or more different viscosities may be employed. Instead of soluble pyroxylin there may be used other forms of nitrocellulose, other cellulose esters, e.g. cellulose acetate, or cellulose ethers, e.g. ethyl or benzyl cellulose. The ethyl alcohol may be replaced by isopropyl, butyl or amyl alcohol, toluene, benzene, xylene, naphtha or combinations thereof, whilst the ethyl acetate may be used in conjunction with butyl acetate or may be replaced by other acetates, e.g. isopropyl, amyl or isoamyl acetate or "pentacetate," or by ethyl oxybutyrate, butyl or ethyl lactate, the mono-methyl or -ethyl ether of ethylene glycol, acetone or alkylene oxides, e.g. diethylene oxide, or mixtures thereof. The dibutyl phthalate may be omitted or replaced by other plasticizers, e.g. other mono- or dialkyl phthalates, camphor or ethoxyethyl phthalate. Specifications 346,397, [Group VII], 361,317; 363,623, [Group VII], 395,767, [Group III], 399,525, 406,030, [both in Group VII], 410,178, 411,815, and 411,920, [all in Group III], are referred to. The Specification as open to inspection under Sect. 91 contains also a second example of an adhesive comprising "low viscosity ethyl cellulose B," "medium viscosity ethyl cellulose B," ethyl acetate, and dibutyl phthalate. This subject-matter does not appear in the Specification as accepted.