Patent GB-871105-A (GB)
Title: Improvements in the incorporation of thermosetting synthetic resins in linen textilefabrics
Inventor: WOOD FREDERICK CHARLES
IPC: D06M15/423
Filed: 1956-04-19
Abstract: Linen textile fabrics having a thermosetting synthetic resin within and substantially not between the fibres are produced by treating them by a process according to Specification 437,361 in which, in a first stage, the fabric is impregnated with a resin-forming condensation product containing an acidic or potentially acidic catalyst, the fabric then being heated to form such resin and thereafter being subjected to a swelling, or swelling and shrinking, treatment and in which, in a second stage, the fabric is further impregnated with a resin-forming condensation product containing an acidic or potentially acidic catalyst, the fabric again being heated to form such resin without thereafter being subjected to a swelling, or swelling and shrinking, treatment, the process being characterized in that the resin-forming condensation product in both stages in a low-viscosity resin-forming condensation product, which penetrates within the fibres of the fabric, formed from urea and formaldehyde in the molecular proportion of formaldehyde to urea of 1,4-2,5 : 1 and the amount of resin formed in the fabric as a result of the first impregnation, and remaining in the fabric after the swelling, or swelling and shrinking, treatment being 1-13%, the amount of resin formed in the fabric as a result of the second impregnation being 1-9% and the total amount of resin in the fabric being 4-18%, all calculated on the dry weight of the fabric before treatment.  The molecular proportions of formaldehyde to urea are calculated on the basis that a quantity of a solution of ammonia in water of S.G. 0,88, equivalent to 8,8% by weight, calculated on the urea, is to be added as condensing agent, appropriate adjustments being made when a larger or smaller quantity of ammonia or no condensing agent or a condensing agent other than ammonia is used.  The swelling agent may be caustic soda of mercerizing strength and the catalyst may be a weak acid, e.g. tartaric acid, a compound, such as ammonium dihydrogen phosphate, which liberates acid on heating, or the acid salt of a polybasic acid having a dissociation constant in water of not less than 10-6 with a metal of which a less acid salt with the same polybasic acid is precipitated before said acid salt on concentration and/or on heating the solution, e.g. sodium dihydrogen phosphate and magnesium sulphate.  The resin may be formed in either or both stages in atmospheres containing more than 50% of superheated steam, and the low-viscosity resin-forming condensation products formed from urea and formaldehyde may be alkylated.  The fabrics may be treated with a lubricating agent, e.g. a methylol derivative of a condensation product of a higher fatty acid chloride with a polyethylene polyamine or a dimethylol stearyl melamine.  The fabrics, which preferably have not been mercerized before resin treatment, contain at least 25% by weight of flax and the other fibres, if present, may be, e.g. cotton, regenerated cellulose and nylon.  The treated fabrics have good crease-resisting properties and smooth drying properties. Specification 704,143, 827,645, 827,647 and 846,875 also are referred to.