GB422027A - Improvements in or relating to processes for manufacturing artificial or reconstructed leather - Google Patents

Abstract

A process employing felting operations for making artificial leather from mixtures of disintegrated scraps and cuttings of leather or hides or both and rubber latex is characterized in that the mixtures employed contain one or more of the oxides and hydroxides of metals and metalloids belonging to groups higher than Group II of the Periodic Classification of the Elements. Oxides and hydroxides of aluminium, silicon and titanium, and oxides of vanadium, iron and nickel may be used. The oxides &c. may be added as such or produced by precipitation in situ in an aqueous dispersion of disintegrated scraps, or may be mixed with oils and ground into the mixture of rubber latex and fibre. About 5-15 per cent of oxides &c. are used, calculated on the dry disintegrated cuttings. The cuttings may be tanned or untanned. In an example, 230 kg. of chrome tanned hide cuttings are washed, neutralized and defibred in the presence of water. A certain amount of vegetable fibres may then be added. The tanned fibres are then partially detanned by adding 4 kg. Seignette's salt, 45 kg. chromine are incorporated, and a second tanning is carried out by adding 30 kg. of a chrome tanning agent, the acid produced being neutralized by sodium carbonate, and then 20 kg. of a vegetable tanning agent; the mass is then worked until complete tanning takes place. At this stage 20 kg. titanium dioxide is added, either as such or produced in situ by adding ammonium hydroxide and titanium chloride, and dispersed in the mixture. Vulcanizing agents, accelerators, antiagers and dyestuffs are then added and the mixture is conveyed to containers or direct to the feeding channel of a paper-making machine where it is mixed with 170 kg. latex having 40 per cent dry rubber content, or the latex may be more dilute. Just before the mixture reaches the wire net forming the endless conveyer of the paper-making machine a coagulating solution, e.g. of sodium chloride is added. The latex may contain either sulphur or accelerator, but not both, to obviate risk of premature vulcanization. Specifications 247,089, 315,413, [both in Class 70], and 365,564 are referred to. The Specification as open to inspection under Sect. 91 comprises also the use of rubber other than as latex. This subject-matter does not appear in the Specification as accepted.