WO1998059106A1

WO1998059106A1 - Stainblocking agent

Info

Publication number: WO1998059106A1
Application number: PCT/NL1997/000359
Authority: WO
Inventors: Stephen Anthony Chapple; François Albertus BARKHUYSEN
Original assignee: Implico BV
Current assignee: Implico BV
Priority date: 1997-06-25
Filing date: 1997-06-25
Publication date: 1998-12-30
Anticipated expiration: 1999-12-25
Also published as: AU3194197A

Abstract

The invention provides a stainblocking agent for a polyamide textile material. The stainblocking agent comprises a normally water-soluble resin, which is the free sulphonic acid form of a condensation of sulphonated 4,4'-dihydroxydiphenyl sulphone and formaldehyde, and an effective amount of sodium lauryl sulphate to enhance the light-fasteness of the stainblocking agent. The invention also provides a method for imparting stain resistance to a polyamide textile material which comprises treating the material by applying an effective amount of the stainblocking agent agent to impart stain resistance to the material.

Description

Title : Stainblocking agent

THIS INVENTION relates to the stainblocking of polyamide textile materials, more particularly but not exclusively wool textile materials.

According to one aspect of the invention, there is provided a stainblocking agent for a polyamide textile material, the stainblocking agent comprising a normally water- soluble resin, which is the free sulphomc acid form of a condensation product of sulphonated

4, 4 '-dihydroxydiphenyl sulphone (DDS) and formaldehyde, and an effective amount of sodium lauryl sulphate to enhance the light-fastness of the stainblocking agent.

By a polyamide textile material is meant a textile material having fibres containing polyamide linkages such as wool, nylon, et.al.

Typically, the stainblocking agent comprises 2.5 - 97% m/m of the resin.

An important feature of the invention is that the resin is used in its free sulphonic acid form without being neutralised to a metal salt form. The stainblocking agent may comprise 0.02 - 10% m/m of the sodium lauryl sulphate (sodium dodecyl sulphate), more preferably 0.3 - 4.2% m/m of the sodium lauryl sulphate, the sodium lauryl sulphate permitting generation of a foam for application purposes.

The sodium lauryl sulphate may serve as a wetting and foaming agent, to facilitate the generation of foam for purposes of application of the stainblocking agent.

Typically, the stainblocking agent comprises an aqueous solution of the resin and the sodium lauryl sulphate.

According to another aspect of the invention, in a method for imparting stain resistance to a polyamide textile material which comprises treating the material by applying an effective amount of a stainblocking agent to impart stain resistance to the polyamide textile material, the stainblocking agent comprising a normally water-soluble resin, which is the free sulphonic acid form of a condensation product of sulphonated 4,4'-dihydroxydiphenyl sulphone and formaldehyde, the improvement which comprises adding to the resin an effective amount of sodium lauryl sulphate to enhance the light-fastness of the stainblocking agent.

The stainblocking agent can be applied at different concentrations and wet pick up, according to the type of polyamide textile material being treated.

Typically, the stainblocking agent is applied in the form of an aqueous solution in an amount sufficient to provide 2 - 10 % solids of said stainblocking agent based on the mass of the polyamide textile material, and the sodium lauryl sulphate is present in said stainblocking agent in an amount of 5 - 20% by mass based on said resin content of said stainblocking agent, the sodium lauryl sulphate permitting generation of a foam for application purposes.

More preferably, the sodium lauryl sulphate is present in said stainblocking agent in an amount of 10 - 15% by mass based on said resin content of said stainblocking agent.

The stainblocking agent may be applied to the polyamide textile material, for example wool carpeting, as a foam i.e. in a foam medium. The foam can be generated by hand or by machine. Likewise, application of the stainblocking agent to the textile material may be effected by hand or by machine.

After treatment with the stainblocking agent, the textile material can be dried at room temperature or at temperatures normally used for the drying of wool or other polyamide textile material in industrial and commercial applications.

The Applicant has found that the light-fastness of the stainblocking agent is also improved by rinsing the treated product before drying. Thus, the invention extends to a method comprising the further steps of, in succession, rinsing and drying the treated polyamide textile material. Routine experimentation will usually be employed, bearing practical and economic considerations in mind, to obtain the optimum parameters of the stainblocking agent and its method of application.

The invention extends to a treated polyamide textile material with resistance to staining and enhanced light-fastness, whenever treated by the method as described above.

The invention will now be described, by way of example, with reference to the following non-limiting illustrative examples and tests.

Test Methods

Stain resistance was determined by application of a stain by standard procedures (Wools of New Zealand T.M. 282 and adaptions based on this test method) to the sample and leaving the stain to set for periods varying between 30 minutes and 24 hours before rinsing the sample under cold water. The following stains were used:

Red acid food dye, containing FD&C Red 40 (0,08 g/1). Coffee, Nescafe Classic™ (14,67 g/1). Red wine, Drostdy-Hof Claret Select™.

The difference in colour (ΔE) and in hue (ΔH) between the unstained control sample and the stained sample were measured on an ICS Micromatch 2000 Spectrophotometer. The ΔE value signifies the colour difference between the stained sample and an unstained control. The ΔH value signifies a change in hue between the stained sample and an unstained control. The lower the ΔE or ΔH value, the smaller the change in colour difference or hue. In addition, the Stain Rating (SR grade) based on the IWS (International Wool Secretariat) Standard Staining Scale, was used. A SR grade of 8 represents no staining and 1 very severe staining.

The fastness to light of the samples was determined by exposure in a Xenotest (Wools of New Zealand T.M. 133). The exposed samples were then compared to unexposed samples and rated on the British Standards Institute grey scale for change in colour, where a value of 5 represents no change and 1 severe change in shade. First fade represents the fading of a blue standard 3 exposed in a Xenotest to a grey scale rating of 4, Full fade represents the fading of a blue standard 4 exposed in a Xenotest to a grey scale rating of 4. The brightening effect was determined by measurement of the chroma value (ΔC) on a spectrophotometer. The ΔC value signifies a change in chroma (brighter/flatter) between the treated sample and an untreated control.

Abrasion resistance was determined by abrading treated carpet samples for 2500 revolutions in a Hexapod. The change in stain resistance compared to unabraded samples was established by means of colour difference values (Wools of New Zealand T.M. 282).

Fastness to dry cleaning was determined by a laboratory simulation of a commercial dry- cleaning procedure. Samples of wool aircraft blanket were placed in a clean solution of perchloroethylene (liquor ratio 10: 1). The sample was then agitated for 15 minutes at 40°C in a Linitest, after which excess solvent was removed by squeezing followed by drying. Stained samples were also dry cleaned commercially to establish dry cleanability.

Fastness to washing was determined by washing samples in a household automatic washing machine (Defy Automaid)^[R1, using a washing powder recommended for automatic washing machines. (Skip™, lg/50g fabric). Samples were given a wool wash cycle at 40 °C, followed by three rinses and a final spin.

^[R] denotes registered trade marks.

Example 1 (Invention)

Preparation of Stainblocking Agent

Acetic anhydride (500g) was added to a three-neck flask fitted with a mechanical glass stirrer and positioned in a water bath at 75-80°C. Concentrated sulphuric acid (98%, 300g) was weighed out. The acetic anhydride was acidified using a small quantity of the concentrated sulphuric acid. 4,4'-dihydroxydiphenyl sulphone (Diphone A, Yorkshire Chemicals, 500g) was then added as a steady stream with continuous stirring. Then immediately the remainder of the concentrated sulphuric acid was added via a dropping funnel, at an even rate of addition over a period of one hour with stirring. The resulting reaction mixture was heated and stirred at 100° C for 8 hours. The reaction mixture was then allowed to cool overnight. The reaction mixture was then heated to 100 °C with stirring. Water (300g) was added as a steady stream and without lowering the reaction temperature too far. Then immediately after the addition of the water, aqueous formaldehyde (37% , 133g) was added steadily with continuous stirring, over a period of 15 minutes. The reaction was continued for a period of 2^xk hours and during the final stages of polymerisation acetic acid was removed. An anionic surfactant sodium lauryl sulphate (80g) was then added to the resultant partially sulphonated free acid resin and then water added to give an aqueous solution having the solids content required, typically between 30 - 45% solids. For the following tests, aqueous solutions containing 5%, 7.5%, 10% and 15% sodium lauryl sulphate as a percentage of the solids content of the resin (o.w.s) were prepared and further diluted according to the wet pick-up required (see Methods of Treatment below). The pH of the stainblocking agent was 1.5. A control stainblocking agent prepared as above but omitting the sodium lauryl sulphate (i.e. 0% (o.w.s) sodium lauryl sulphate) was also prepared for test purposes.

Example 2 (Comparative Test)

Further stainblocking agents containing 10% (o.w.s) surfactant were prepared for comparative test purposes as in Example 1, replacing sodium lauryl sulphate by the commercial surfactants given below.

Alcopol O60 (Allied Colloids) 60% sodium dioctyl sulphosuccinate in alcohol and water. Anionic wetting agent,

Alcopol 650 (Allied Colloids) non-ionic detergent and wetting agent, Kieralon OL (B.A.S.F.) mixture of anionic and non- ionic components, Leophen RA (B.A.S.F.) sodium salt of an organic sulphonic acid. Tergitol TN (Union Carbide) Trimethyl nonanol ethoxylate. Ultravon HD (Ciba-Geigy) mixture of emulsifiers with detergent properties. Slightly anionic. Example 3 (Comparative Test)

For comparative test purposes, stainblocking agents containing 10% (o.w.s.) sodium lauryl sulphate were prepared as in Example 1 but the resin used in Example 1 was replaced by the commercial sulphonated resins set out below. It should be noted that the resin of the invention described in Example 1 is in the free acid form (i.e. not neutralised) while these commercial resins have been neutralised to some extent during manufacture and prior to addition of sodium lauryl sulphate to form the stainblocking agents. The pH of the stainblocking agents was set to 3,5, prior to application, using acetic acid or sodium hydroxide.

Baykanol HLX (Bayer) - a condensation product of naphthalene sulphonic acid and bishydroxyphenyl sulphone. Erional RF (Ciba-Geigy) - a condensation product of aromatic sulphonic acids.

FX-369 (Minnesota Mining and Manufacturing Corporation) - a sulphonated phenolic resin.

Example 4 (Invention)

For test purposes, a stainblocking agent was prepared as Example 1 (10% (o.w.s.) sodium lauryl sulphate), but adjusting the pH of the stainblocking agent to 3,5, prior to application, with sodium hydroxide. Example 5

For test purposes, the stainblocking agent of the invention prepared as in Example 1 (10% (o.w.s.) sodium lauryl sulphate) was applied to wool fabric by the exhaust method described in Method (d). For comparative test purposes the commercial sulphonated phenolic resin FX-369 was also applied to wool fabric by the exhaust method described in Method (d).

Example 6 (Comparative Test)

For comparative test purposes, stainblocking agents were prepared using commercial sulphonated resins (set out below) and mixing them with a commercial anionic wetting agent (set out below). The stainblocking agents were applied to wool fabric and nylon fabric according to methods (e) - (g).

Intratex N (Crompton & Knowles) - Dyeing auxiliary (a sulphonated phenol-formaldehyde condensation product)

Intratex N-8 150% - (Crompton & Knowles) Dyeing auxiliary (a sulphonated resin) Cenegen 7 - (Crompton & Knowles) Dyeing auxiliary - an anionic surface active agent (wetting agent)

Example 7 (Comparative Test)

For comparative test purposes, stainblocking agents were also prepared using the commercial sulphonated resins as described above for Example 6, but the commercial anionic wetting agent, Cenegen 7, was replaced with sodium lauryl sulphate. Methods (e) - (g) were used to apply the stainblocking agents.

Example 8 (Invention)

For test purposes, a stainblocking agent was prepared as for Example I ( 10% (o.w.s.) sodium lauryl sulphate) and applied using the same application methods as for Example 6.

Example 9 (Comparative Test)

For comparative test purposes, a stainblocking agent was prepared as in Example 1 but excluding the sodium lauryl sulphate . Cenegen 7 was then mixed with the sulphonated resin at a ratio of 0.67: 1 (solids), sulphonated resin to anionic wetting agent and applied using the method (e).

Example 10 (Comparative Test)

For comparative test purposes, stainblocking agents were prepared using commercial sulphonated resins as described in Example 6, and mixing them with either a commercial anionic wetting agent, as described in Example 6, or sodium lauryl sulphate, for purposes of foam application to wool and nylon carpet using the method (a). Example ll(Invention)

For test purposes, stainblocking agents were prepared as in Example 1 ( 10% (o.w.s) sodium lauryl sulphate), but the pH of the sulphonated resin was adjusted prior to the addition of the sodium lauryl sulphate. The pH of some of the stainblocking agents was then readjusted, if necessary.

Materials

For Examples 1 to 4 and 11, the following wool and/or nylon carpet types were used for evaluation purposes:

Zirpro-treated wool aircraft blanket fabric with a mass/unit area of 275 g/m² was used for evaluation purposes (Example 1). Zirpro (registered trade mark) is a proprietary flame- proofing agent.

For Examples 5 to 10, undyed wool fabric with a mass/unit area of 149 g/m², dyed wool fabric with a mass/unit area of 251.8 g/m² and undyed, heat set, nylon 6.6 fabric with a mass/unit area of 125 g/m² were used for evaluation purposes. Methods of Treatment

For wool and nylon carpets the stainblocking agents in the tests were applied at a level of 5,5% solids on mass of the wool pile of the carpet and at a level of either 4,4% or 2% solids on mass of the nylon pile of the carpet, by methods (a) - (b):

Method (a)

The stainblocking agent was whipped into a foam and applied to the surface of the carpet at a 50% (on weight of pile) wet pick-up. The carpet was then given a short steaming (1 minute) treatment followed by a quick surface rinse. The sample was then vacuumed using a vacuum cleaner to remove excess moisture and dried at 80-100°C. This procedure was used on carpets in most cases unless otherwise stated.

Method (b) (i)

The stainblocking agent was whipped into a foam and applied to the surface of the carpet at either 50% or 100% (on weight of pile) wet pick-up. After vacuuming to remove excess moisture, the carpet was left for a period of between 1 and 10 minutes and then a solution of a commercial steam detergent carpet cleaner (1,9 ml/100 ml water) was applied. The carpet was then vacuumed to remove excess moisture and left to air dry at room temperature.

Method (b) (ii)

The stainblocking agent was applied together with a commercial carpet cleaner and the sample vacuumed either immediately or after a period of between 2 and 10 minutes. The sample was then left to air dry at room temperature. The pH of an aqueous extract of the carpet, after application of the stainblocking agent of the invention (prepared as in Example 1, 10% (o.w.s.) sodium lauryl sulphate), was found to be in the range 3.2 - 3.3.

For wool fabric and/or nylon fabric the stainblocking agent was applied using the following methods:

Method (c)

The stainblocking agent was padded (5,5% solids) onto said Zirpro-treated wool aircraft blanket on a Benz padding mangle at a 100% wet pick-up (o.w.f.) - o.w.f. means on weight of fabric. The fabric was then dried at 100°C, rinsed in cold water before final drying.

Method (d)

To a bath having a liquid to fabric ratio of 30: 1, at a temperature of 98 °C and with the pH set to 4 with acetic acid, 8% (solids on weight of fabric) of the stainblocking agent was added and allowed to circulate for 3 - 5 minutes. The pH was then rechecked and adjusted if required. 100% wool fabric was then placed in the bath for a period of 30 minutes, to allow for exhaustion of the stainblocking agent onto the fabric. The fabric was then removed and dried or removed, rinsed and then dried.

Method (e)

The stainblocking agent was applied to wool fabric to give a level of 5.5% (solids) for wool and 0.75% (solids) for nylon o.w.f (on weight of fabric) of the stainblocking agent. The application pH was set at 3 with formic acid, where necessary. The sample was treated for 20 minutes at 74°C at a liquor to goods (fabric) ratio of 40: 1. After treatment the sample was rinsed and dried.

Method (f)

Wool fabric was dyed with an acid levelling dye using a standard acid levelling dye method. After dyeing the bath was dropped and replaced with clean water. The stainblocking agent

(5.5% o.w.f (solids)) was added to the bath and the pH adjusted to 2.5 with sulphamic acid, where necessary. The temperature of the bath was raised to 60°C and maintained for 30 minutes. The sample was removed and rinsed and dried.

Method (g)

Wool or nylon fabric was padded (impregnated and squeezed out) with a wet pick up of 100% to give 5.5 % (solids) for wool and 0.42% (solids) for nylon o.w.f of the stainblocking agent. The pH of the padding solution was set, prior to padding, to 2.5 with sulphamic acid, if necessary. The padded sample was then steamed for a period of 1 or 2 minutes and subsequently rinsed in water prior to drying.

The results of tests conducted on said polyamide carpet and fabric samples using the stainblocking agents prepared in Examples 1 - 11 and applied by said methods are tabulated below. Table 1

Demonstration of improvement in light-fastness on treated wool carpet.

o.w.s - surfactant added as a percentage of the solids content of the resin

The results in Table 1 show the improvement in light-fastness and the superiority of sodium lauryl sulphate according to the invention compared to other anionic and non-ionic surfactants. The results also show the improvement in light-fastness brought about by inclusion of a rinse in the treatment. Table 2

Demonstration of improvement in stain resistance on treated wool carpet.

o.w.s - surfactant added as a percentage of the solids content of the resin. * staining occurred in the base of the pile.

The results in Tables 1 and 2 show the stainblocking agent of the invention, incorporating sodium lauryl sulphate, as having a better combination of stain resistance and light-fastness when compared to other anionic and non-ionic surfactants. Table 3

Comparison of the stain resistance and light-fastness of the stainblocking agents of the invention when applied to wool carpet, with that of stainblocking agents prepared using commercial sulphonated resins, and with the untreated wool carpet (Control).

The stainblocking agents of the invention showed a better combination of stain resistance and light-fastness, when compared to the stainblocking agents prepared using commercial sulphonated resins.

Table 4

Comparison of stain resistance of wool carpet treated with the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) with that of the untreated wool caφet (Control).

A significant reduction in the staining propensity of the acid food stain was obtained on the caφet treated with the stainblocking agent of the invention, even after a staining period of 24 hours. The stainblocking agent of the invention also improved the stain resistance of the caφet against the more difficult coffee and red wine stains.

Table 5

Comparison of stain resistance of the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) applied to wool caφet with the treated wool caφet which has subsequently been abraded.

It is clear that the stainblocking agent of the invention is still effective after abrasion of the caφet, since all the samples passed the requirements of the TM 282 test method. Furthermore, the stainblocking agent of the invention is equally effective on a wide range of different caφet constructions. Furthermore, an increase in the staining time from 30 minutes to the more severe 24 hours, although resulting in a deterioration of the stainblocking effect, still resulted in acceptable stain resistance. Table 6

Comparison of the light-fastness and stain resistance of the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) when applied to wool caφet by different foam application methods.

Lightfastness pass requirement (TM 133) = 4.

SR pass requirement (TM 282) = 5.

The results indicate that the stainblocking agent of the invention could be applied by widely different methods without adversely affecting light-fastness. Although Method (a), which includes steaming, gave improved stain resistance, Method (b) (i) and Method (b) (ii), which involve air drying, a necessity for in situ treatments, also provided an adequate level of stain resistance.

Table 7

Comparison of the stain resistance and light-fastness of nylon caφet treated by different foam application methods with the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate).

The results show that a significant reduction in the staining propensity of the acid food stain was obtained on nylon caφets treated with the stainblocking agent of the invention, even after a staining period of 24 hours. Treatment of the caφet by method (a) gave a lightfastness equal to that of the untreated caφet.

Table 8

Comparison of the stain resistance and light-fastness of wool and nylon caφet treated with the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate), applied by different foam application methods using a commercial caφet cleaning machine.

The results indicate that the stainblocking agent of the invention, when applied by commercial caφet cleaning machines, gives similar results as regards stainblocking and lightfastness to those obtained in laboratory scale applications, highlighting the effectiveness of sodium lauryl sulphate according to the invention in enhancing light-fastness while maintaining a high level of stain resistance.

Table 9

Comparison of the stain resistance of the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) when applied to Ziφro-treated wool aircraft blanket (method (c)), and ease of cleaning of said blanket, with that of untreated Ziφro-treated wool aircraft blanket.

The stainblocked samples exhibited good stain release properties regarding all three stains, highlighted by the ease of stain removal either by washing or by dry-cleaning. The Ziφro treatment does not seem to have an adverse effect on the efficiency of the invention.

Table 10

Fastness to dry-cleaning and fastness to washing of the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) when applied to Ziφro-treated wool aircraft blanket (method (c)).

Untreated (stained) ΔH = 3.11 It is clear that the effect of repeated dry-cleaning cycles on the stainblocking is minimal. There has been a progressive deterioration in stainblocking with repeated washing. However, even after 10 washing cycles, the treated fabric still showed a smaller hue difference value than that of an untreated stained sample.

Table 11

Stain resistance and light-fastness of wool fabric exhaust treated with the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s) sodium lauryl sulphate) and comparison with the commercial sulphonated phenolic resin FX-369 applied to wool fabric in similar manner.

The stainblocking agent of the invention can also be applied by normal exhaust methods. It shows superior stain resistance compared with the commercial sulphonated phenolic resin, FX-369, and a better combination of stain resistance and light-fastness. Table 12

Comparison of stain resistance and light-fastness of the stainblocking agent of the invention when applied to wool fabric (method (e)), with that of stainblocking agents prepared using commercial sulphonated resins, and with untreated wool fabric (Control).

The stainblocking agent of the invention showed similar stain resistance to the commercial stainblocking agent comprising Intratex N and Cenegen 7 (ratio sulphonated resin to wetting agent 0.67: 1 (solids)), however, the stainblocking agent of the invention showed superior stain resistance compared to the Intratex N / sodium lauryl sulphate combinations. The use of Cenegen 7 in combination with the sulphonated resin of the invention (Example 9) resulted in a loss of stain resistance. The light-fastness was similar for most samples, although the stainblocking agent of the invention showed better light-fastness than the Intratex N / sodium lauryl sulphate 10: 1 (solids) combination - the same ratio of sulphonated resin to sodium lauryl sulphate as used in the invention.

Table 13

Comparison of stain resistance and light-fastness of the stainblocking agent of the invention when applied to wool fabric after dyeing (method (f)), with that of stainblocking agents prepared using commercial sulphonated resins, and with untreated dyed wool fabric (Control).

The stainblocking agent of the invention showed marginally better stain resistance compared to the commercial sulphonated resins / Cenegen 7 combinations but superior stain resistance compared to the commercial sulphonated resins / sodium lauryl sulphate combinations. The light-fastness was similar for all samples.

Table 14

Comparison of the stain resistance of the stainblocking agent of the invention when padded onto dyed wool fabric (method (g)) with that of stainblocking agents prepared using commercial sulphonated resins, and with untreated wool fabric (Control).

The stainblocking agent of the invention showed superior stain resistance compared to both the Intratex N / Cenegen 7 and Intratex N / sodium lauryl sulphate combinations, further illustrating the usefulness of sodium lauryl sulphate according to the invention. Table 15

Comparison of the caφet colour difference after treatment and the light-fastness of the stainblocking agent of the invention with that of stainblocking agents prepared using commercial sulphonated resins when applied to wool caφet by foam application (method (a)).

staining occurred in the base of the pile

Although the stainblocking agent of the invention showed similar to marginally better stain resistance compared to the commercial sulphonated resins / Cenegen 7 and commercial sulphonated resins / sodium lauryl sulphate combinations, the stainblocking agent of the invention, importantly, showed less colour difference to the wool caφet after application and superior light-fastness compared to the other stainblocking agent combinations again illustrating the superior performance of sodium lauryl sulphate according to the invention. Table 16

Comparison of stain resistance and light-fastness of the stainblocking agent of the invention when applied to nylon fabric (method (e)), with that of stainblocking agents prepared using commercial sulphonated resins, and with untreated nylon fabric (Control).

The stainblocking agent of the invention showed similar stain resistance to the commercial stainblocking agent, comprising Intratex N and Cenegen 7 (ratio sulphonated resin to wetting agent 0.67: 1 (solids)), however the stainblocking agent of the invention showed superior stain resistance compared to the Intratex N / sodium lauryl sulphate combinations, especially after a 24 hour staining period. Table 17

Comparison of stain resistance of the stainblocking agent of the invention with that of stainblocking agents prepared using commercial sulphonated resins when applied to nylon caφet by foam application (method (a)).

The stainblocking agent of the invention showed a better combination of stain resistance and light-fastness compared to the other stainblocking agents, having similar stain resistance but exhibiting superior light-fastness.

Table 18

The effect of the pH of the sulphonated dihydroxydiphenyl sulphone resin prior to the addition of sodium lauryl sulphate on the stainblocking and light-fastness of the stainblocking agent of the invention.

Neutralizing the sulphonated resin of the invention prior to the addition of sodium lauryl sulphate resulted in a decrease in stainblocking and light-fastness, illustrating the importance of adding the sodium lauryl sulphate to the free acid form of the sulphonated dihydroxydiphenyl sulphone resin, in accordance with the invention, in order to provide a stainblocking agent having a high level of stain resistance and superior light-fastness. Acidification after neutralization resulted in an increase in stainblocking and light-fastness, but not to the same level as when the sodium lauryl sulphate was added to the free acid form of the sulphonated resin in accordance with the invention.

Table 19

The brightening effect of the stainblocking agent of the invention (prepared as in Example 1 with 10% (o.w.s.) sodium lauryl sulphate) when applied by different methods to wool caφet and fabric.

The stainblocking agent of the invention exhibits a brightening effect when applied by the different methods to wool fabric and caφet.

It is an advantage of the invention that the stainblocking agent is effective as a stainblocking agent for wool and nylon, especially when applied in accordance with the method described. The stainblocking agent is effective against a broad range of stains, including acid food dyes as well as coffee and red wine. Furthermore, the stainblocking agent exhibits good fastness to light and shows good abrasion resistance.

With regard to the mode of application of the stainblocking agent, it is applied in a foam medium, which means that it can be applied to wool during the final stages of processing. For example, it can be applied as a treatment to the pile of wool caφets during caφet backing, or as a foam or pad application to wool upholstery fabric. Furthermore, since it is applied in a foam medium, it can be applied in situ. For example, it can be applied to already fitted wool caφets or to wool upholstery fabric. This method of application makes it easy to re-apply the stainblocking agent if required. The stainblocking agent can also be applied by various conventional exhaust processes.

A further advantage of the invention is that the stainblocking agent increases the brightness of dyed wool samples when it is applied during the later stages of dyeing (this effect occurs with a number of different dyestuffs). The stainblocking agent also increases the brightness of previously dyed wool samples that are subsequently treated with the stainblocking agent by exhaust or padding methods, and, when applied as a foam to wool caφets, the stainblocking agent can be shown to have a brightening effect (mainly on dark colours).

Claims

CLAIMS:

1. A stainblocking agent for a polyamide textile material, the stainblocking agent comprising a normally water-soluble resin, which is the free sulphonic acid form of a condensation product of sulphonated 4,4'-dihydroxydiphenyl sulphone and formaldehyde, and an effective amount of sodium lauryl sulphate to enhance the light-fastness of the stainblocking agent.

2. A stainblocking agent as claimed in Claim 1, in which the stainblocking agent comprises 2.5 - 97% m/m of the resin.

3. A stainblocking agent as claimed in Claim 1 or Claim 2, in which the stainblocking agent comprises 0.02 - 10% m m of the sodium lauryl sulphate, the sodium lauryl sulphate permitting generation of a foam for application puφoses.

4. A stainblocking agent as claimed in Claim 3, in which the stainblocking agent comprises 0.3 - 4.2% m/m of the sodium lauryl sulphate.

5. A stainblocking agent as claimed in any one of Claims 1 - 4 inclusive, in the form of an aqueous solution of the resin and the sodium lauryl sulphate.

6. In a method for imparting stain resistance to a polyamide textile material which comprises treating the material by applying an effective amount of a stainblocking agent to impart stain resistance to the polyamide textile material, the stainblocking agent comprising a normally water-soluble resin, which is the free sulphonic acid form of a condensation product of sulphonated 4, 4 '-dihydroxydiphenyl sulphone and formaldehyde, the improvement which comprises adding to the resin an effective amount of sodium lauryl sulphate to enhance the light-fastness of the stainblocking agent.

7. A method as claimed in Claim 6, in which the stainblocking agent is applied in the form of an aqueous solution in an amount sufficient to provide 2 - 10% solids of said stainblocking agent based on the mass of the polyamide textile material, and the sodium lauryl sulphate is present in said stainblocking agent in an amount of 5 - 20% by mass based on said resin content of said stainblocking agent, the sodium lauryl sulphate permitting generation of a foam for application puφoses.

8. A method as claimed in Claim 7, in which the sodium lauryl sulphate is present in said stainblocking agent in an amount of 10 - 15% by mass based on said resin content of said stainblocking agent.

9. A method as claimed in any one of Claims 6 - 8 inclusive, in which the stainblocking agent is applied to the polyamide textile material as a foam.

10. A method as claimed in any one of Claims 6 - 9 inclusive, the method comprising the further steps of, in succession, rinsing and drying the treated polyamide textile material.

11. A treated polyamide textile material with resistance to staining and enhanced light-fastness, whenever treated by the method as claimed in any one of Claims 6 - 10 inclusive.

12. A new stainblocking agent for a polyamide textile material, substantially as described herein.

13. A new method for imparting stain resistance to a polyamide textile material, substantially as described herein.