Patent GB-924928-A (GB)
Title: Improvements relating to a bonded fibrous structure
IPC: D04H1/54
Filed: 1958-04-09
Abstract: 924,928. Bonded fibrous fabrics; laminates. J. A. STALLARD, and T. P. DAVIES. July 9, 1959 [April 9, 1958; May 4, 1959], Nos. 11276/58 and 15234/59. Classes 42 (2) and 140. A method of making a bonded fibrous structure comprises forming a fibrous structure containing at least a substantial proportion of fibres of at least one high molecular weight, longchain, synthetic polymer capable of being softened by any of the swelling agents specified below, treating the fibrous structure with sufficient swelling-agent to cause the fibres to soften and adhere together without losing their fibrous state, allowing the fibrous structure and the swelling agent to remain in contact until bonding has occurred and then causing or allow-- ing all or most of the swelling agent to be removed. The term " fibres " includes filaments and the term " swelling agent " includes a solvent for the fibres. The swelling agent may be applied by spraying or by pouring in streams or drops. Suitable fibres are those of polyethylene terephthalate, polyamides (e.g. nylon), acrylic compounds, vinyl chloride/vinyl acetate copolymers, vinyl chloride/aerylonitrile copolymers, polyvinylidene chlorides, cellulose triacetates, polyalkylenes such as polyethylene and polypropylene. The swelling agents specified are phenol, cyclohexanol, 1,3,5 - trichlorobenzene, dibutyl tartrate, isopropyl amines, nitrobenzene, ethylene glycol, 2-ethyl-hexanol, acetophenone, diphenyl, benzyl alcohol, octyl cresol, diethylphthalate, trichlorethyl phosphate, p-toluene sulphonamide, monochloracetic acid, dichlor-acetic acid, trichloracetic acid, #-naphthol, pyrogallol, 4-chlor - 3 :5- xylene-1-ol, 0-nitro phenol, benzophenone, resorcinol, pyrocatechol, salicylic acid, hexyl resorcinol, p-chlorophenol, hydroquinone; also chl ral, or a solution of chloral hydrate in water, ether or chloroform. For acrylic fibres propylene, ethylene or other alkylene carbonate; acetone cyclohexanone, and dimethylformamide are specially suitable. Mixtures of the above fibres or with minor proportions of other fibres may be used. Bonding may be carried out in the cold, or heat may be applied to accelerate the process. The fibres may be formed into a web by carding, garretting, air deposition or fluid papermaking techniques. A web may be first formed by the foregoing methods and then impregnated according to the invention; or alternatively a mass of fibres may first be impregnated, then (optionally) kneaded or passed through a scutcher and finally carded to form a web. A number of carded plies may be formed into a wadding. The treated web may be subjected to heat with or without pressure. In the former case apparatus as shown in Fig. 2 may be used wherein electrically heated jaws 10 and 11 of a press are provided with smooth removable plates 12 and 13. An impregnated web 5 is placed between the plates and may then be heated under pressure. Instead of using the apparatus shown, the web may be passed through a calender with heated bowls or pressed between flat platens, or between expanded metal grids, or other means producing local bonding only. The products may be used as or in air, oil or other filters, clothing interlining, and decorative fabrics. A web of nylon fibres impregnated with 5% aqueous phenol, dried, and hot pressed is stated to be useful as a surfacing tissue for polyester laminates.