GB1571188A - Treating textile fibres with anionic prepolymers - Google Patents

Description

(54) TREATING TEXTILE FIBRES WITH ANIONIC PREPOLYMERS (71) We, I. W. S. NOMINEE COMPANY LIMITED, a British Company of Wool House, Carlton Gardens, London, S.W.I., and LANKRO CHEMICALS LIMITED, a British Company of Emerson House, Albert Street, Eccles, Manchester M30 OBH, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method of treating textile fibres, in particular by the application of anionic pre-polymers.

A number of polymers or pre-polymers are known which can be used to treat textile materials. Treatments to confer shrink-resistance or dimensional stability to keratinous material with anionic prepolymers are disclosed in our British Patents Nos. 1,423,342, and 1,423,341, and 1,480,213 which relate to Bunte salt prepolymers and in British Patent No. 1,419,306 which relates to bisulphite blocked isocyanate prepolymers.

In particular, the following types of water-soluble polyether polymers have been shown to confer shrink resistance on wool:

In these formulae 'n' is from 2-30 inclusive and 'x' is from 1 to 4 inclusive.

All these polymers can be applied to wool fabric from aqueous baths by padding techniques and cured or crosslinked to give an insoluble polymer film on the wool surface, which imparts machine washability. Crosslinking can be brought about by drying the treated fabric at elevated temperatures, by steaming, by batching in the presence of sodium bisulphite or, in the case of polymers A and B, by rinsing in a solution containing thiols.

Because of the anionic character of these polymers they exhibit affinity for wool under acidic conditions in a similar manner to acid dyes. Thus at pH 2 substantially complete exhaustion of these polymers from an aqueous bath at 500C can be achieved. However, the crosslinking reactions for all the polymer types, A, B and C show a strong pH dependence, crosslinking not occurring below pH 5.

Consequently, the simple drying of wool treated with polymer A, B or C, for example at a level of 2%4% on the weight of fibre (o.w.f.) at pH 2 will induce little or no crosslinking of the pre-polymer and thus no anti-felting effect is observed. Unfortunately, simply raising the bath pH following exhaustion under acid conditions results in polymer desorption from the fibre back into the aqueous phase, and on drying to achieve crosslinking there is insufficient polymer at the fibre surface to impart anti-felting properties.

It would be very desirable for these polymers to be applicable to wool by an exhaustion technique from long liquors, i.e. from a bath with a water to goods ratio exceeding 5:1, and up to a maximum of, say, 100:1. The invention seeks to provide a method whereby this can be simply achieved in a short application time and at moderate bath temperatures.

According to the present invention there is provided a process of treating textile materials which comprises exhausting an anionic pre-polymer from an aqueous bath onto the material in the presence of divalent metal ions and thiocyanate ions.

The preferred classes of anionic prepolymer include those having a backbone formed from the addition of an alkylene oxide to a polyol and being terminated with either thiosulphate groups or carbamoylsulphonate groups. Both these groups are capable of reacting further to effect cross-linking or curing and it is preferred that at least two of these groups are present per molecule. Preferred members of these classes have been mentioned hereinabove as polymers A, B and C.

The divalent metal may be of Group IIA or Group IIB, and is preferably present as a chloride. Good results have been given by magnesium and calcium chloride and particularly good results are obtained with zinc chloride. It is believed that exhaustion of the prepolymer is promoted by the presence of a complex salt formed by the addition of a salt of thiocyanic acid to the divalent metal salt, such as 7no12.

The amount of metal salt may be varied, for example between 2.5 and 15 g/l with about 5 gil being preferred. Similarly the amount of thiocyanate salt used may be from 5 gil upwards. More than 15 g/l does not improve the effect, and about 10 gil is preferred.

The application temperature may be between 40"C and the boil, but lower temperatures are preferred and about 50"C is usually the optimum. The pH of the treating bath should be slightly acid, for example from pH 3 to 7.5, with pH 5 being preferred. The time of treatment depends on the temperature and may be from 5 minutes to several hours. At the preferred temperature of 50"C an application time of about 20 minutes is preferred.

The process of the invention is particularly applicable to keratinous fibres such as wool and may be applied to woven, knit or non-woven fabric, or to yarns.

The treatment may be carried out in any textile machinery suitable for handling long liquors. For example, dyeing machinery such as winches or sidepaddle dyeing machines may be used. Yarn package or hank drying machines may be used, or dolly washers.

The following Examples are given by way of illustration.

EXAMPLE I An all wool-worsted, 2/2 twill serge fabric (1 kg) was treated on a small winch dyeing machine in an aqueous bath containing ammonium thiocyanate (10 girl), zinc chloride (5 girl) and the Bunte Salt terminated polymer of type A (x=l, n=17) using 30 polymer o.w.f. (total bath volume 30 litres). The procedure was commenced at 250C and the temperature raised slowly to 500C and the bath was maintained at 50"C for 20 minutes. After this time it was observed that the baths were quite clear and gave no precipitate with ammonium thioglycollate (a test for determining Bunte Salts in solution).

The fabric was then dried and heat cured simultaneously using a Famatex tenter set at 1300C. Using an "International Cubex" accelerated washing machine, samples from this treated fabric were washed along with a portion of untreated fabric at a liquor ratio of 15:1 and a temperature of 40"C in pH 7 buffer solution, the weight being made up to 1 kg with polyester makeweights. After 3 hours the treated fabric samples were observed to have shrunk 0V in area whereas the untreated fabric had shrunk 45% in area, and the handle of the fabric after treatment was good.

When drying was omitted and the wool tested in the "Cubex" machine, an area shrinkage of 12% was recorded after 3 hours washing.

EXAMPLE II A scoured Shetland wool sweater was immersed in an aqueous bath containing ammonium thiocyanate (5 girl) and zinc chloride (5 girl). The bath was made up with water to give a liquor ratio of 30:1 and Bunte Salt polymer A was added in an amount corresponding to 2% weight of goods. This bath was then heated slowly to 50"C and maintained at 500C for a further 20 minutes, the goods being thoroughly agitated throughout the whole procedure. The sweater was tumble-dried in the normal manner for + hour at 900C. When tested in the 15 litre "Cubex" test, this treated sweater showed no area shrinkage after 3 hours, whereas an untreated sweater shrank 72% in area.

EXAMPLE III 2-fold 28's wool worsted yarn (10 g) was treated with 2% o.w.f. Bunte Salt polymer A in a laboratory dyeing machine in a bath containing potassium thicyanate (10 girl) and zinc chloride (5 g/l), the bath being made up to 300 ml with water. The procedure of Example I was then followed. After 20 minutes treatment at 500C, the yarns were hydroextracted and dried in a laboratory oven at 600 C. The yarns were then knitted up on a single jersey sampling machine, heat cured at 130"C for 10 minutes and "Cubex" tested as in previous examples. An area shrinkage of the knitted fabric of only 1% was recorded after a 3 hour Cubex washing.

EXAMPLE IV The method of Example I was repeated using worsted serge, but in this case the ammonium thiocyanate was omitted from the bath. After Cubex testing the treated sample for 3 hours, an area shrinkage of 42 /,, was recorded, which was no different from that of the untreated wool.

EXAMPLE V The method of Example I was again followed, but in this case the zinc chloride was omitted from this bath. In this case, the treated fabric gave an area shrinkage of 4196, which was recorded after 3 hours "Cubex" testing.

The results obtained in Examples IV and V illustrate the synergistic effect of the thiocyanate ion and zinc chloride.

EXAMPLE VI Synthappret LKF (Bayer) was reacted with sodium bisulphite to give a water soluble derivative of formula similar to polymer type C. (The method of preparation is described by Guise et. al. J. Text. Inst., 64 (1973) 665). Using the worsted serge of Example I, a treatment was carried out in a bath containing 4 ' o.w.f. Synthappret-bisulphite adduct, ammonium thiocyanate (10 girl) and zinc chloride (5 g/l). The temperature was slowly raised to 500C and the bath maintained at this temperature for 15 minutes. Following hydroextraction, the wool was dried at 130"C for 10 minutes in a forced draught laboratory oven and then "Cubex" tested. An area shrinkage of 0% was recorded after 3 hours washing.

EXAMPLE VII A single jersey fabric of cover factor 1.1 knitted from 2/27's worsted count botany wool yarn was treated under the conditions of Example II with varying quantities of reactants as shown below: NH4SCN (g/l) ZnCl2 (girl) Polymer ( /n owf) ,; Area Shrinkage (3 hours) 10 5 2 5 5 2 35 5 5 4 5 - - Untreated 65 Thus it can be seen that the presence of sufficient ammonium thiocyanate enables the polymer concentration to be reduced to 2% o.w.f. and still give full washability.

WHAT WE CLAIM IS: 1. A process of treating textile materials containing keratinous fibres which comprises exhausting an anionic prepolymer from an aqueous bath onto the material in the presence of divalent metal ions and thiocyanate ions.

2. A process according to Claim 1 wherein the divalent metal is a metal of Group IIA or IIB of the Periodic Table.

3. A process according to Claim 1 or 2 wherein the bath contains 2.5 to 15 gil of a-salt of the metal and 5 to 15 gil of a thiocyanate salt.

4. A process according to Claim 1, 2 or 3 wherein the bath is maintained at a temperature between 40"C and the boil and its pH at 3 to 7.5 during exhaustion.

5. A process according to any preceding claim wherein the anionic prepolymer molecule has a backbone formed by addition of an alkylene oxide to a polyol and is terminated by thiosulphate groups of carbamoylsulphonate groups.

6. A process of treating textile materials substantially as described in any one of Examples I, II, III or VI herein.

7. Textile materials including keratinous fibres treated by the process of any preceding claim.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   preparation is described by Guise et. al. J. Text. Inst., 64 (1973) 665). Using the worsted serge of Example I, a treatment was carried out in a bath containing 4 ' o.w.f. Synthappret-bisulphite adduct, ammonium thiocyanate (10 girl) and zinc chloride (5 g/l). The temperature was slowly raised to 500C and the bath maintained at this temperature for 15 minutes. Following hydroextraction, the wool was dried at 130"C for 10 minutes in a forced draught laboratory oven and then "Cubex" tested. An area shrinkage of 0% was recorded after 3 hours washing.

   EXAMPLE VII A single jersey fabric of cover factor 1.1 knitted from 2/27's worsted count botany wool yarn was treated under the conditions of Example II with varying quantities of reactants as shown below: NH4SCN (g/l) ZnCl2 (girl) Polymer ( /n owf) ,; Area Shrinkage (3 hours)

   10 5 2

   5 5 2 35

   5 5 4 5 - - Untreated 65 Thus it can be seen that the presence of sufficient ammonium thiocyanate enables the polymer concentration to be reduced to 2% o.w.f. and still give full washability.

   WHAT WE CLAIM IS: 1. A process of treating textile materials containing keratinous fibres which comprises exhausting an anionic prepolymer from an aqueous bath onto the material in the presence of divalent metal ions and thiocyanate ions.
2. 2. A process according to Claim 1 wherein the divalent metal is a metal of Group IIA or IIB of the Periodic Table.
3. 3. A process according to Claim 1 or 2 wherein the bath contains 2.5 to 15 gil of a-salt of the metal and 5 to 15 gil of a thiocyanate salt.
4. 4. A process according to Claim 1, 2 or 3 wherein the bath is maintained at a temperature between 40"C and the boil and its pH at 3 to 7.5 during exhaustion.
5. 5. A process according to any preceding claim wherein the anionic prepolymer molecule has a backbone formed by addition of an alkylene oxide to a polyol and is terminated by thiosulphate groups of carbamoylsulphonate groups.
6. 6. A process of treating textile materials substantially as described in any one of Examples I, II, III or VI herein.
7. 7. Textile materials including keratinous fibres treated by the process of any preceding claim.