Patent GB-1339181-A (GB)
Title: Cross-linked phenol-formaldehyde fibres
IPC: D01F6/76
Filed: 1971-10-01
Abstract: 1339181 Phenol-formaldehyde fibres TORAY INDUSTRIES Inc 1 Oct 1971 [2 Oct 1970 23 Dec 1970 13 April 1971 4 May 1971] 45751/71 Heading C3R [Also in Division B5] Cross-linked phenol-formaldehyde fibres are prepared by mixing a novolac resin having a pH of at least 4 with tetraoxymethylene and/or trioxan, melt-spinning the mixture to yield fibres and then curing in the presence of an acid catalyst preferably at a temperature of 0-150‹ C., preferably followed by a heat treatment, at 70-250‹ C. The phenolic component of the resin is preferably phenol or bisphenol A. Suitable acid catalysts include mineral acids, Lewis' acids, sulphonic acids, organic carboxylic acids, acid precursors and acid salts. The catalyst may be used in conjunction with formaldehyde and/or a compound producing formaldehyde. The fibre may be modified by reaction with a compound other than HCHO during or after the curing process to block and/or cross-link the phenolic hydroxy groups. The modifying compound may be the same as the acid catalyst. Suitable modifying compounds include acid halides ; acid anhydrides; a compound of the formula R-(COX) n  wherein R represents a C-C bond, a di-, tri- or quadrivalent acyclic hydrocarbon or an aromatic radical, n = 2-4 and X is a halogen atom; a compound of the formula R-(X) n  wherein R represents -CO-, -Si(R 1 ) 2 -, -P(R 1 )-, -P(O)R 1 )-, -O 2 S-R 2 -SO 2 -, -P-(-R 1 ) 3 - or wherein R 1  is a halogen atom or an organic group such as alkyl, phenyl, alkoxy or phenoxy, n > 2, and X is a halogen atom, and R 2  is phenylene, where Z is -O-, -S-, -CH 2 -, -CO-, When the modification treatment is effected with an halogenated phosphorus compound the fibres are subsequently stabilized by reaction with an epoxy compound such as propylene oxide. In Examples 1 and 2 fibres prepared from a mixture of a phenol-HCHO novolac resin and 10% wt. tetraoxymethylene or trioxan are cured by heating in the presence of one of the following acid catalysts: H 2 SO 4 , PCl 3 , p-toluenesulphonic chloride, oxalic acid, acetyl chloride both in the presence and absence of HCHO. In Example 5 cross-linked fibres are prepared from novolac resins prepared from formaldehyde and (i) a mixture of phenol and p-cresol, (ii) bisphenol A, (iii) phenol, aniline, (iv) phenol, nylon 6 by melt spinning the resins with 10% wt. tetraoxymethylene and then curing the fibres in the presence of p-toluene sulphonic acid. In Example 6 fibres melt spun from a phenol-HCHO novolac and 10% wt. tetraoxymethylene mixture are cured in the presence of HCl and HCHO and then heat treated in the presence of acetic anhydride and one of the following catalysts: p-toluene sulphonic acid, HCl, BF 3  etherate, acetyl chloride, dimethyl formamide hydrochloride, and oxalic acid. In Example 7 fibres prepared from the resin of Example 1 are cured in the presence of various acid chlorides and subsequently heat-treated. In Example 8 fibres are melt spun from the resin mixtures of Example 5 and cured in the presence of one of the following modifying compounds: succinyl dichloride, fumaric acid dichloride, butenetetracarboxylic acid tetrachloride, benzophenonetetracarboxylic acid tetrachloride, naphthalene - 1 - 5 - dicarboxylic acid dichloride, oxalyl chloride, butenetricarboxylic acid trichloride, maleic acid dichloride, isophthalic acid dichloride. In Example 9 fibres melt spun from a mixture of a phenol- HCHO novolac resin and 10% wt. tetraoxymethylene are reacted with various halogenated phosphorus compounds and subsequently stabilized by reaction with propylene oxide.