GB1593858A - Treatment of hydrophilic textile materials - Google Patents

Description

(54) TREATMENT OF HYDROPHILIC TEXTILE MATERIALS (71) We, I.W.S. NOMINEE COMPANY LIMITED, a British Company, of Wool House, Carlton Gardens, London, S.W.I, 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 hydrophilic textile materials with hydrophilic agents by exhaustion from a hydrophobic medium.

Most textile treatments are carried out from an aqueous medium and are known as 'wet' treatments. However, it is often desirable to carry out treatments from hydrophobic media, especially in cases where the textile material may be damaged or otherwise affected by aqueous systems, or where for reasons of effluent disposal aqueous systems are not favoured. Dry cleaning is an example of such hydrophobic or 'solvent' processing, and dry-cleaning machines can be used for a number of solvent treatments of textiles.

One such treatment, for textiles comprising keratin fibres, is the application of an anti-felting or 'shrink-resist' agent. British Specification No. 1,396,509 describes a process for imparting shrink resistance to wool by applying an organo-silicone system from an organic solvent. A disadvantage of this process is that there is no chemical exhaustion of the organo-silicone system onto the wool, and thus the concentration of it in the solvent must be high enough for sufficient to be left on the wool (typically 3% by weight) after centrifuging. Thus if the wool is centrifuged to 100% expression, the solvent must contain 3% by weight of the organo-silicone. At a typical liquor ratio of 20:1 this means that the liquor contains twenty times more organo-silicone than is needed to treat the wool.A consequence of this is that cured silicone polymer builds up in the dry-cleaning machine, which must be shut down periodically and thoroughly cleaned out.

This is both expensive and inconvenient.

The invention seeks to provide a method whereby textile treatments may be carried out in an organic solvent but in which the treating agents exhaust onto the textile material.

According to the present invention there is provided a method of treating a hydrophilic textile material with a textile treating agent soluble in a polar solvent in which the agent is dissolved in the polar solvent, the resulting solution is emulsified in a greater quantity of hydrophobic liquid such that the polar solution is the disperse phase, and the textile material is immersed in the emulsion and maintained therein with agitation until the polar phase has substantially exhausted onto the textile material.

It is necessary, if the process is to be successful, that the textile material should be sufficiently hydrophilic to attract the polar disperse phase, and cellulosic or keratinous materials, especially wool, are of primary interest. The textile material may be in any suitable form, e.g. loose stock, top, silver slubbing, yarn, fabric or garment pieces.

Often it is convenient to treat made-up garments.

The preferred polar solvent is water, but the solvent may also comprise other polar liquids. The treating agent may be any hydrophilic, usually water-soluble, compound used for treating or finishing textile materials, e.g. mothproofing agents, soilproofing agents, antistatic agents, or shrinkresistant agents, but not flameproofing agents.

It is preferred to employ the process of the invention to apply shrink-resist agents, but not flameproofing agents.

It is preferred to employ the process of the invention to apply shrink-resist agents to keratinous materials.

Preferred classes of water-soluble shrinkresist agents include Bunte salt terminated polymers or prepolymers, polycarbamyl sulphonate polymers or prepolymers, and thiol polymers or prepolymers having a watersolubilizing group or groups such as a carboxyl group. All these polymers or prepolymers are capable of application by padding methods from aqueous solution to wool piece goods and when cured will confer shrinkresistance to the goods.

A preferred class of thiol polymers is esters of poly(tetramethylene oxide)diol (which may be derived from the polymerisation of tetrahydrofuran) and thiomalic acid in such proportions as to ensure at least two thiol groups per molecule and terminal carboxylic acid groups.

The Bunte salt polymers which may be used include those disclosed in our British Patent No. 1,423,342 and German Published Specification No. 2.436,035, and in British Patent Application No. 28298/76 (Serial No.

1587406). Thiol polymers are disclosed in the said German specification.

Most suitable Bunte salt polymers (organic polymeric thiosulphates) comprise molecules having at least two, and preferably at least 3, Bunte salt groups per molecule, and contain poly(oxyalkylene) chains.

The preferred class of Bunte salt polymers may be derived from the condensation of an alkylene oxide with glycerol by reacting the resulting poly(oxyalkylene)triol with monochloroacetic acid and subsequently replacing the chlorine atoms with SSO, groups by treatment with a soluble thiosulphate such as sodium thiosulphate. The alkylene oxide may be, for example, propylene oxide or tetramethylene oxide.

Preferred polycarbamyl sulphonate prepolymers are disclosed in British Specification No. 1,419,306. Typical examples are formed from the reaction product of hexamethylene diisocyanate with a condensation product of propylene oxide with glycerol. The terminal isocyanate groups are then reacted with sodium bisulphite to give the polycarbamyl sulphonate.

All of the agents selected should be sufficiently soluble in the polar solvent for the polar disperse phase to contain enough agent to treat the textile. For example, if 1 kg. of wool is to be treated with 5% of the fibre weight of a shrink-resist agent from a 90/10 by weight non-polar solvent/polar solution emulsion, at 20:1 liquor:goods ratio, then 2 kg. of an aqueous phase must contain 50 grams of agent dissolved therein. At a 10:1 liquor ratio the aqueous phase must be twice as concentrated.

The hydrophobic medium may be any inert organic solvent, but common 'dry' textile processing solvents such as trichloroethylene or perchloroethylene are preferred.

Since the disperse phase containing ionic polymers is highly polar in contract to the hydrophobic medium, it is usually preferred to mix some hydrophobic solvent, optionally together with a less hydrophobic co-solvent, into an aqueous or other polar solution before emulsifying the latter with the main bulk of the hydrophobic medium. If this is not done the emulsion may not be stable, having a tendency to crack.

The hydrophobic solvent mixed into the aqueous phase is conveniently the same as that used for the solvent phase. The cosolvent, if used, may be any semi-polar organic solvent, for example an alcohol or ester, especially ethanol or isopropanol.

The aqueous disperse phase forms a minor proportion of the emulsion and typically comprises up to 20% and preferably up tp 10% by weight. Much more aqueous phase leads to the emulsion taking on too much of the character of an aqueous treatment rather than a solvent treatment.

Usually, the method may be carried out in a dry-cleaning machine. The wool goods are first given a cleaning cycle to remove contaminants, and then fresh solvent is fed to the cleaning chamber. A separate emulsion concentrate of the shrink-resist agent (and catalyst if required) is made up and fed to the cleaning chamber from a mixing chamber provided for the purpose of injecting additives. The emulsion will necessarily be cloudy and a visual indication that exhaustion has taken place is given when it becomes clear. The goods are then hydroextracted, dried and cured at elevated temperature.

Any catalyst required, e.g. a base for Bunte salt polymers, may be separately emulsified, or mixed with the polymer and emulsified immediately before use. Emulsions containing both catalyst and polymer are naturally not stable for long periods but separate emulsions are stable and may be mixed together just before use.

It should be pointed out that the process of the invention will work with agents which chemically exhaust from aqueous systems, e.g. the amphoteric polymers disclosed in our German Published Specification No.

2,609,206. and with polymers which will not normally exhaust from aqueous systems without assistance, e.g. the thiol polymers of the aforementioned German Specification No. 2,436,035. The process of the invention depends on the physical attraction of the polar disperse phase to the hydrophilic textile material, carrying the agent with it. All the aqueous phase is adsorbed on the textile material, and the solvent phase is recycled.

Since solvent milling of wool is carried out by an aqueous disperse phase in a solvent, wool goods may be simultaneously milled and treated with hydrophilic agents by adjusting the ratio of water to give milling conditions.

The invention will be illustrated further by the following examples, in which all parts and percentages are expressed by weight unless the context indicates otherwise: Wash Test The wash test employed in these Examples consisted of 1, 2 or 3 hour agitation in a 'Cubex' (Trade Mark) washing machine in 15 1. of pH 7 buffer at 40"C with a 1 kg. load.

All samples were spin dried for 2 minute and then hung in the air until dry (IWS Test Method 185).

Area Shrinkage Area shrinkage was determined by measuring the change in spacing of previously applied bench marks, and results are expressed as % area shrinkage. Less than 10% represents a pass.

Example 1 The following stock compositions were made up, by sequential mixing of the components with constant stirring: Resin Stock 100 parts Polyether Bunte salt prepolymer solution, 40% solids, (Lankrolan SR3-Lankro Chemicals Ltd.) 100 parts Ethanol 100 parts Perchloroethylene Catalyst Stock 100 parts Water 1 part Sodium bicarbonate 1 part Solvent milling aid (Alcosol ve Allied Colloids) The resin stock was then added to the catalyst stock with constant stirring until a uniform dispersion was obtained, which contained 10% active resin solids. A fabric knitted to cover factor 0.9 from 2/8's Shetland wool yarn was placed in a dry cleaning machine and given a cleaning cycle to remove dirt, oil and contaminants.Fresh perchloroethylene was then introduced into the cleaning chamber, and sufficient resin/catalyst mixture added through a mixing chamber to give 4% resin solids on the weight of wool (o.w.w.). The mixture was sprayed evenly into the chamber while the fabric was being agitated to give a uniform treatment.

The fabric was dried in the machine and the resin cured at 90"C for 15 minutes.

The fabric was found to be adequately milled and, as can be seen from the test results below, fully machine washable to Superwash standard.

Test Results: 1 hr. wash 2 hr. wash 3 hr. wash -5 0 Example 2 In this case a single resin/catalyst stock was made initially as follows: 1 part Sodium bicarbonate 50 ,, Water 100 ,, Lankrolan SR3 100 ,, Perchloroethylene 100 ,, Ethanol The resultant dispersion contained 11.4% active resin solids.

The dispersion was added, in accordance with the procedure of Example 1, to knitted fabric of 1.1 cover factor made from 2/27's botany wool yarn to give 4% solids o.w.w.

Substantially no milling was observed, and the fabric was fully machine washable as can be seen from the wash test results: Test Results: 1 hr. wash 2 hr. wash 3 hr. wash 0 2 6 Example 3 Example 2 was repeated using the following resin stock: 100 parts Polycarbamyl sulphonate prepo lymer (synthappret 4694--Bayer AG) 20 parts Alcosolve C 100 parts Perchloroethylene The resultant dispersion contained 22.7% active resin solids and because it contained no catalyst was very stable.

The treated fabric was fully machine washable: Test Results: I hr. wash 2 hr. wash 3 hr. wash 0 0 4 Further it was found that milder curing conditions (5 minutes at 90to) were sufficient to cure the resin fully.

Example 4 Example 3 was repeated replacing the Synthappret prepolymer with a product formed by condensing propylene oxide with glycerol, capping the resultant triol with hexamethylene diisocyanate, forming the carbamyl sulphonate from 80% of the terminal isocyanate groups and protonating the remainder by treatment with acid in anhydrous conditions as described in our German Specification No. 2,609,206.

Again a fully machine washable product resulted: Test Results: 1 hr. wash 2 hr. wash 3 hr. wash 0 3 6 WHAT WE CLAIM 15: 1. A method of treating a hydrophilic

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

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. conditions. The invention will be illustrated further by the following examples, in which all parts and percentages are expressed by weight unless the context indicates otherwise: Wash Test The wash test employed in these Examples consisted of 1, 2 or 3 hour agitation in a 'Cubex' (Trade Mark) washing machine in 15 1. of pH 7 buffer at 40"C with a 1 kg. load. All samples were spin dried for 2 minute and then hung in the air until dry (IWS Test Method 185). Area Shrinkage Area shrinkage was determined by measuring the change in spacing of previously applied bench marks, and results are expressed as % area shrinkage. Less than 10% represents a pass. Example 1 The following stock compositions were made up, by sequential mixing of the components with constant stirring: Resin Stock 100 parts Polyether Bunte salt prepolymer solution, 40% solids, (Lankrolan SR3-Lankro Chemicals Ltd.) 100 parts Ethanol 100 parts Perchloroethylene Catalyst Stock 100 parts Water 1 part Sodium bicarbonate 1 part Solvent milling aid (Alcosol ve Allied Colloids) The resin stock was then added to the catalyst stock with constant stirring until a uniform dispersion was obtained, which contained 10% active resin solids. A fabric knitted to cover factor 0.9 from 2/8's Shetland wool yarn was placed in a dry cleaning machine and given a cleaning cycle to remove dirt, oil and contaminants.Fresh perchloroethylene was then introduced into the cleaning chamber, and sufficient resin/catalyst mixture added through a mixing chamber to give 4% resin solids on the weight of wool (o.w.w.). The mixture was sprayed evenly into the chamber while the fabric was being agitated to give a uniform treatment. The fabric was dried in the machine and the resin cured at 90"C for 15 minutes. The fabric was found to be adequately milled and, as can be seen from the test results below, fully machine washable to Superwash standard. Test Results: 1 hr. wash 2 hr. wash 3 hr. wash -5 0 Example 2 In this case a single resin/catalyst stock was made initially as follows: 1 part Sodium bicarbonate 50 ,, Water 100 ,, Lankrolan SR3 100 ,, Perchloroethylene 100 ,, Ethanol The resultant dispersion contained 11.4% active resin solids. The dispersion was added, in accordance with the procedure of Example 1, to knitted fabric of 1.1 cover factor made from 2/27's botany wool yarn to give 4% solids o.w.w. Substantially no milling was observed, and the fabric was fully machine washable as can be seen from the wash test results: Test Results: 1 hr. wash 2 hr. wash 3 hr. wash 0 2 6 Example 3 Example 2 was repeated using the following resin stock: 100 parts Polycarbamyl sulphonate prepo lymer (synthappret 4694--Bayer AG) 20 parts Alcosolve C 100 parts Perchloroethylene The resultant dispersion contained 22.7% active resin solids and because it contained no catalyst was very stable. The treated fabric was fully machine washable: Test Results: I hr. wash 2 hr. wash 3 hr. wash 0 0 4 Further it was found that milder curing conditions (5 minutes at 90to) were sufficient to cure the resin fully. Example 4 Example 3 was repeated replacing the Synthappret prepolymer with a product formed by condensing propylene oxide with glycerol, capping the resultant triol with hexamethylene diisocyanate, forming the carbamyl sulphonate from 80% of the terminal isocyanate groups and protonating the remainder by treatment with acid in anhydrous conditions as described in our German Specification No. 2,609,206. Again a fully machine washable product resulted: Test Results:

1 hr. wash 2 hr. wash 3 hr. wash 0 3 6 WHAT WE CLAIM 15: 1. A method of treating a hydrophilic

textile material with a textile treating agent soluble in a polar solvent in which the agent is dissolved in the polar solvent, the resulting solution is emulsified in a greater quantity of hydrophobic liquie such that the polar solution is the disperse phase, and the textile material is immersied in the emulsion and maintained therein with agitation until the polar phase has substantially completely exhausted onto the textile material.

2. A method according to claim I wherein the polar solvent is water.

3. A method according to claim I or 2 wherein the hydrophobic liquid is a dry cleaning solvent.

4. A method according to any of claims I to 3 wherein a quantity of a hydrophobic solvent is mixed with the polar solvent and the mixture subsequently emulsified in a larger quantity of hydrophobic solvent.

5. A method according to claim 4 wherein the mixture also contains a cosolvent which is less hydrophobic than the said hydrophobic solvent.

6. A method according to any preceding claim wherein the aqueous disperse phase constitutes not more than 20% by weight of the emulsion.

7. A method according to any preceding claim wherein the hydrophilic textile material comprises keratinous fibres and the treating agent is a shrink-resist agent.

8. A method according to claim 7 wherein the shrink-resist agent is selected from Bunte salt terminated polymers or prepolymers, polycarbamyl sulphonate polymers or prepolymers, and thiol polymers or prepolymers having a water-solubilizing group or groups.

9. A method of treating a hydrophilic textile material substantially as described in any one of Examples 1 to 4 herein.

10. A hydrophilic textile material treated by a method according to any preceding claim.