GB2221928A - Waterproofing treatment of textile materials - Google Patents

Abstract

A method of treatment of a textile material in order to confer on it water resistant properties, which method comprises treating the textile material with a liquid medium comprising a ketene dimer of the general formula [R<1>R<2>C=C=O]2 (I> wherein each of the groups R<1> independently represents an alkyl or alkenyl group having at least 8 carbon atoms, or an aryl, aralkyl or alkaryl group, and each of the groups R<2> independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The textile material may be a woven, knitted or non-woven fabric, a yarn, fibres or filaments.

Description

TREATMENT OF TEXTILE MATERIALS This invention relates to a method of treatment of textile materials in order to confer on them water resistant properties.

In accordance with the present invention there is provided a method of treatment of a textile material in order to confer on it water resistant properties, which method comprises treating the textile material with a liquid medium comprising a ketene dimer of the general formula [R1R2c-c=O2 (I) wherein each of the groups R1 independently represents an alkyl or alkenyl group having at least 8 carbon atoms, or an aryl, aralkyl or alkaryl group, and each of the groups R2 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

The textile material may, for example, be a knitted or woven fabric, a yarn, a non-woven fabric, or fibres or filaments for preparation of any of the above.

It may be, for example, an item of clothing, or a furnishing item, for example, a carpet or curtain material or furniture covering fabric, or a tenting item, for example a tenting or tarpaulin sheet, or a yarn, fibre or filament for manufacture into any of the above.

It may be a natural material or a man-made material, or a mixture of both.

It is believed that the method of the invention is most effective in relation to materials which are rich in nucleophilic groups, for example, hydroxy, thiol, amino, imino and carboxy groups. Preferred examples are wool, cotton, and blended polyester/cotton.

In relation to the above definition of a compound of formula I, preferred alkyl or alkenyl groups R1 have from 8 to 24 carbon atoms. Preferred cycloalkyl groups, (which may be mono- or multicyclic) are C(6-10) cycloalkyl, especially cyclohexyl. Preferred aryl and alkaryl groups are phenyl and 2-naphthyl, optionally substituted by 1-3 C(1-10) alkyl groups. Preferred aralkyl groups are phenyl-C(1-4) alkyl, especially benzyl, and napthyl-C(1-4) alkyl.

Preferably, each of the groups R1 independently represents an alkenyl or, most preferably, an alkyl group.

Especially suitable as alkyl groups for R1 are octyl, decyl, dodecyl, tetradecyl, hexedecyl, octodecyl, eicosyl, docosyl and tetracosyl groups.

Especially preferred are decyl, decosyl, and, especially tetradecyl and hexadecyl.

Examples of ketene dimers in which the groups R1 may be alkenyl groups include the ketene dimers derived from C18 unsaturated acids, for example, oleic, linoleic and linolenic acids.

Preferred alkyl groups R2 have 1-4 carbon atoms, most suitably being methyl and ethyl. Most preferred for R2, however, is hydrogen. Preferably, both symbols R2 in a given dimer compound represent hydrogen The groups R1 in any given compound need not be the same and the groups R2 in any given compound need not be the same. Moreover a mixture of compounds of formula I may be used in any given treatment in accordance with the method of the invention.

In a particularly preferred method according to the invention the ketene dimer employed is prepared from a mixture of stearic and palmitic acids, preferably from a mixture of these two acids in approximately equal proportions.

The liquid medium is preferably an aqueous medium; the medium is suitably a solution or emulsion of a ketene dimer in'water. Such ketene dimers are available or conveniently prepared as aqueous emulsions, which are diluted in water before use. Such emulsions suitably comprise one or more emulsifying agents. Emulsifying agents of the ionic or the non-ionic type may be employed. A preferred emulsifying agent is a cationic amine modified starch having the formula

where X is starch, R3 is an alkylene, hydroxyalkylene, phenylalkylene or alkylalkylene group, and R4 and R5 are each an alkyl, aryl, aralkyl or cycloalkyl group, or a hydrogen atom. Such materials are more fully described in UK patent specification No.903416.

The pH of the medium used to treat the fabric is suitably in the range 5-9, preferably 6.5 - 7.5.

The medium may contain a wetting agent, preferably thermally degradable and/or volatile.

Suitable as wetting agents are, for example, C(1-6) alcohols, such as isopropanol.

Suitable methods of applying the ketene dimer to a fabric include exhaustion, padding and spraying. The exhaustion technique involves the immersion of the fabric in a liquid medium containing the ketene dimer until uptake of dimer is complete - typically when the concentration of ketene dimer in the medium has fallen to substantially zero. The weight ratio of liquid: fabric is suitably in the range 2:1 - 100:1, preferably, 5:1 40:1 and most preferably 7:1 - 15:1. The time required for exhaustion is generally 15-30 minutes. The ultimate weight of exhausted ketene dimer is suitably 0.1 - 5% o.w.t. (on weight of textile material), preferably 0.3 2%, most preferably 0.5 - 1%.

Application by padding involves wetting the fabric in a liquid medium having a relatively high concentration of the ketene dimer(s), for example by dipping, followed by squeezing the fabric through a pad mangle, the nip pressure being set to permit the retention of a desired proportion of the liquid medium.

In a preferred method according to the invention an aqueous medium containing a ketene dimer as herein defined is applied to the textile material at a temperature in the range of 10-800, preferably 15-400 and most preferably 20-300C, (conveniently ambient temperature), the textile material is dried and, once dried, the textile material is subjected to an elevated temperature in the range 50-1500C, preferably 70-1100C.

Suitably, the dried textile material is subjected to the elevated temperature for a curing period, typically several minutes, for example 5-10 minutes.

It has been found that the method of the invention increases the resistance to surface wetting of fabrics which have been treated or whose yarn has been treated . This water resistance appears to continue after washing, with only slight diminution in its effectiveness, in certain cases only. Depending on the particular ketene dimer or dimers employed in the method, other advantages may arise, for example, stain resistance, softening effects or garment lubricating effects.

In a further aspect of the present invention there is provided a textile material treated as described herein.

The invention will now be further described, by way of example, with reference to the following examples describing particular methods of carrying out the invention.

Example 1 Application by Exhaustion onto Woollen Knitwear 65 kilos of 100% wool garments were scoured in a 600 litre side paddle machine at a temperature of 400C using a soap and detergent mix. The batch was thoroughly rinsed and then the machine refilled with water at 25 0C to provide a liquor ratio (ie., ratio of weight of water : weight of garments) of approximately 10:1 and a pH of 7.5.

The garments were circulated whilst 3.3 kilos (5% o.w.t.) of "Aquapel 360X" * were added over 2 minutes, having previously been diluted tenfold with water. The solution became cloudy and the garments were circulated until it became clear (approximately 20-25 minutes).

*"Aquapel 360X" (Trade Mark), sold by Hercules (UK) Ltd, is an aqueous emulsion containing about 10% wt., of an alkyl ketene dimer based on 1:1 stearic:palmitic acids, and stabilized by a cationic amine modified starch, as described previously.

The side paddle machine was then drained and the garments subjected to hydroextraction followed by drying in a heated tumble dryer. The inlet and outlet temperature was monitored to provide drying over about 20 minutes followed by a heat curing stage for the dried knitwear, at approximately 700C for a further 10 minutes.

After cooling, the garments had a pleasant handle (feel), similar to that of scoured but otherwise untreated garments.

Spray Rating Testing of the garments was carried out (as hereinafter described), to BS 3702:1982.

Several garments of the batch were tested and provided ratings of 5, showing excellent resistance to wetting.

Some garments were then subjected to several cycles of hand and machine washing at 400C using a mild detergent, followed by thorough rinsing. Spray Rating Testing provided the results shown in Table 1.

TABLE 1 AVERAGE OF SEVERAL EXAMPLES

I I I I I I Scoured j 5% o.w.t. After 1 j After I I but I "Aquapel wash 5 5 Washes jUntreated I I I I I I I I I I I Spray I I Rating 2 5 5 4-5 Result Example 2 Application by Exhaustion onto Cotton Knitwear 8.75 kilos of 100% cotton knitwear were wetted out in a small side paddle machine (200 litres) with 150 litres of water at 270C (pH 7.2).The garments were circulated whilst 0.44 kilos of "Aquapel 360X" were added, having been previously diluted with 5 litres of water. Exhaustion occurred over 20 minutes, the end point being shown by a clarification of the liquor.

After hydroextraction the garments were dried in a heated tumble dryer for 30 minutes, followed by a further 10 minutes at 70 0C (garment temperature), for heat curing.

Again, the garments had a very acceptable handle, similar to that of untreated but scoured garments.

Results from the Spray Rating Tester both before and after washing were as follows; TABLE 2 AVERAGE OF SEVERAL EXAMPLES

Scoured 1 5% o.w.t. After 1 j After but "Aquapel i Wash 1 5 Washes Untreated 360X" I I I I I I I Spray I Rating ! 0 1 4-5 i 4-5 3-4 Result Example 3 Application by Padding onto Cotton Tenting Fabric A cotton tenting fabric (300 g/sq m) was immersed in a solution of "Aquapel 360X" in water containing some isopropanol (wetting agent).

Liquor "Aquapel 360X" 200 ml Isopropanol 100 ml Water 700 ml After thorough wetting out, the fabric was passed through a pad mangle with the nip pressure set to provide about 50% pick up (10% add on of "Aquapel 360X"). The fabric was then dried in a forced draft oven at 1100C for 20 minutes which ensured complete drying and some curing, once the fabric was dry.

After drying the fabric was tested for water repellency using the cone test. This involves the formation of the fabric into a cone which is then filled with water and left for a period of time. The effectiveness is determined by the lack of penetration of water through the fabric. This fabric produced no wetting out or penetration during the test. Also the fabric handle was far superior to that produced using traditional water repellent agent.

Example 4 Application by padding onto Cottoni Polyester Tenting Fabric A 50/50 cotton/polyester rip-stop tent fabric was treated as in Example 3 to produce a sample having 8.4% add on of "Aquapel 360X".

After drying the fabric, testing using the cone test gave an excellent result with no penetration and no wetting out of the fabric. Again, the handle was far superior to that produced using traditional water repellents.

Spray Rating Testing Spray Rating Testing as referred to above was carried out on a spray rating tester, model 113, provided by James H. Heal & Co. Ltd., of Halifax, England, in accordance with their instructions. The testing was carried out to assess the resistance of a fabric to surface wetting by water, not to predict its rain penetration resistance, since the test does not measure penetration of water through the fabric. Testing was in accordance with the requirements of BS 3702: 1982, 150 4920 and AATCC Test Method 22-1980. Briefly, the tester comprises a funnel having a spray nozzle at its lower end, mounted above a specimen holder which retains the specimen beneath the nozzle at an angle of 450 to the horizontal. The centre of the specimen is 150 mm below the centre of the nozzle face.

The fabric to be tested is located in the specimen holder, with the warp direction along the "North/South" axis. 250 ml of distilled water at 200C +/- 20C is poured steadily but quickly into the funnel.

As soon as the spray ceases, the specimen holder is removed, turned face downwards and the edge is tapped smartly, twice, against a solid object. The sprayed surface is immediately assessed by comparing its appearance with descriptive and photographic standards, and untreated control garments.

At least 3 specimens are taken and tested from different places in each fabric.

The spray ratings are coded as follows;- 5 - No wetting of sprayed surface, no adherence of small drops 4 - No wetting of sprayed surface, but adherence of small drops 3 - Wetting of sprayed surface at small, discrete areas 2 - Wetting of half or more of sprayed surface, usually caused by merging of small discrete areas The reader's attention is directed to all papers and documents which are filed concurrently with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in the specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiement(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (11)

1. A method of treatment of a textile material in order to confer on it water resistant properties, which method comprises treating the textile material with a liquid medium comprising a ketene dimer of the general formula [R1R2C=C=O)2 (I) wherein each of the groups R1 independently represents an alkyl or alkenyl group having at least 8 carbon atoms, or an aryl, aralkyl or alkaryl group, and each of the groups R2 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

2. A method as claimed in Claim 1 wherein each of the groups R1 independently represents a C(8-24) alkyl or alkenyl group, a C(6-10) cyclohexyl group, a phenyl or 2naphthyl group optionally substituted by 1-3 C(1-10) alkyl groups, or a phenyl-C(1-4) alkyl or naphthyl-C(1-4) alkyl group.

3. A method as claimed in Claim 1 or 2, wherein each of the groups R1 independently represents an alkenyl or alkyl group.

4. A method as claimed in any preceding claim, wherein each of the groups R1 represents an alkyl group.

5. A method as claimed in any preceding claim, wherein each of the groups R1 represents a C(12-18) alkyl group.

6. A method as claimed in any preceding claim, wherein each of the groups R2 represents a hydrogen atom.

7. A method as claimed in any preceding claim, wherein a ketene dimer is employed which has been prepared from a mixture of stearic and palmitic acids.

8. A method as claimed in any preceding claim, wherein the ketene dimer is applied to the textile material in an aqueous emulsion which is stabilised by a cationic amine modified starch having the formula

where X is starch, R3 is an alkylene, hydroxyalkylene, phenylalkylene or alkylalkylene group, and R4 and R5 are each an alkyl, aryl, aralkyl or cycloalkyl group, or a hydrogen atom.

9. A method as claimed in any preceding claim, wherein an aqueous medium containing a ketene dimer as defined in any of Claims 1 to 7 is applied to the textile material at a temperature in the range 10-800C, the textile material is dried and, once dried, the textile material is subjected to an elevated temperature in the range 501500C for a curing period.

10. A textile material which has been treated in accordance with a method as claimed in any preceding claim.

11. A method of treatment of a textile material, or a textile material so treated, substantially as hereinbefore described with reference to the Examples.