WO1991002117A1

WO1991002117A1 - Treatment of wool and woollen goods

Info

Publication number: WO1991002117A1
Application number: PCT/AU1990/000332
Authority: WO
Inventors: Ronald Clark Thompson
Original assignee: Brandella Corporation (Australia) Pty. Ltd.
Priority date: 1989-08-03
Filing date: 1990-08-03
Publication date: 1991-02-21
Also published as: CA2037910A1

Abstract

A process for enhancing the shrinkage and felting resistance of wool or woollen goods, includes subjecting the wool or woollen goods to a predominantly oxidising pretreatment with a pretreatment agent which is a salt of preoxymonosulphuric acid, and applying to the fibres of the thus pretreated wool or woollen goods a fibre coating agent which is a polyether substituted with aziridine groups.

Description

TREATMENT OF WOOL AND WOOLLEN GOODS

This invention relates to the treatment of wool and woollen goods and in particular is concerned with a process for reducing the shrinkage and felting of woollen goods. The terms "wool" and "woollen" embrace both pure wool and blends in which wool is the predominant component.

A widely used class of treatment to render woollen goods susceptible to machine washing entails the coating of the wool fibres with a polymer which is effective to mask the scale structure or bond adjacent fibres together or both, and thereby to render the products resistant to both shrinkage and felting. Application of shrink and felt resistance polymers to wool or woollen goods generally requires a pretreatment such as oxidation or low-level chlorination to increase the fibre surface energy.

One known chlorination-resin process is the Basolan ( Registered Trademark) process promoted by BASF of Ludwigshafen, Germany. In this process, the woollen goods are treated with Basolan SW, a low viscosity cationic polyether with reactive aziridine groups, dissolved in isopropyl alcohol. This process has the advantage that it may be applied to exhaustion in a bath, with or without pre-chlorination depending upon the results desired and the nature of the product to be treated. Examples of the Basolan composition are believed to be set forth in British patent 1470243.

A further known commercial process is the Crosil (trademark) process promoted by Crossfield Textile Chemicals of Warrington, United Kingdom. Application to exhaustion of a pair of resins comprising a base elastomer and an associated external crosslinker is preceded by a pretreatment to exhaustion with Crosil salt, in an acid bath, with pH around 4 and the temperature in the range of 20 to 35°C. Previous scouring and milling are assumed and a wetting agent may be necessary. Crosil salt is a tri-potassium salt of peroxymonosulphuric acid and the pretreatment with this salt is predominantly an oxidising process. It is thought that the Crosil salt weakens the sulphur links in the helical molecular structure of the wool fibres so that the coating agent molecules can be intermingled, both to produce crosslinking of molecules and hydrogen bonding

SUBBTITUT6 SHEET and to smooth over the sides.

The Crosil process was developed primarily for goods produced by the woollen system of wool processing and it has been found that it is less effective when applied to goods produced by the worsted system of processing. Another "known chlorination shrinkproofing process is the Hercosett

(Trademark) process, which is presently especially promoted as a technique for producing woollen garments which may be machine washed, so called "Superwash" garments. In this case, the Hercosett treatment is applied to the dyed yarn rather than the garment, an approach which has the disadvantage of poor economies of scale when small yarn volumes are required, for example for waist and neck bands of unusual colour on school uniform jumpers.

It is therefore an object of the present invention to provide an improved shrinkage and felting resistance treatment for woollen goods which is adaptable with good results to worsted system goods, and especially to completed worsted system garments.

It has b-έen surprisingly found that enhanced shrinkage and felting resistance can be achieved by a process which, in a simple and convenient embodiment, in substance combines the pretreatment stage of the Crosil process with the resin treatment stage of the Basolan process. The combination is so effective that the goods are not only able to be machine washed without shrinkage and felting but can be repeatedly tumble dried. No prior shrinkage and felting resistance treatment has to date produced goods able to be repeatedly tumble dried. The inventive process is adaptable to achieve this with products which are of excellent consumer quality and handle, and remain so after regular washing and tumble drying.

The invention accordingly provides a process for enhancing the shrinkage and felting resistance of wool or woollen goods, comprising the steps of: a. subjecting the wool or woollen goods to a predominantly oxidising pretreatment with a pretreatment agent which is a salt of preoxymonosulphuric acid; and b. applying to the fibres of the thus pretreated wool or woollen goods a fibre coating agent which is a polyether substituted with aziridine groups.

SUBSTITUTE SHEET The pretreatment agent is preferably an alkali metal salt of peroxymonosulphuric acid, most preferably a potassium salt of peroxymonosulphric acid. Crosil salt is particularly preferred. The coating agent is preferably a compound of the general formula (I):

wherein R¹ to R⁷ are identical or different and are hydrogen or alkyl radicals of 1 to 4 carbon atoms, Q is the radical obtained by removal of the hydrogen atoms of N hydroxyl groups from an n-hydric alcohol or phenol, n is 2 or 3 and X is a polyether chain of oxybutylene units and/or oxypropylene units with or without oxyethylene units, said polyether chain having a C:O atomic ratio of not less than 2.67:1 and a molecular weight from 150 to 1,500 if n = 2, and from 150 to 3,000 if n = 3. Most preferably, the coating agent is Basolan SW.

The goods may be woven or other fabrics or cloth, or, in a particularly preferred embodiment, completed garments.

To enhance the effectiveness of the pretreatment, the goods are preferably first immersed in a bath containing a suitable wetting agent. The non-ionic wetting/scouring agent Croscour HVT (Trademark) marketed by the aforementioned Crosfield Textile Chemicals is found to be very effective for this purpose. The wetting agent is selected, and its proportion selected, with a particular view to avoiding foaming in the bath.

The pretreatment and coating agent application steps are advantageously carried out to exhaustion of the respective agents in successive baths, for example water baths. The baths are preferably continuously agitated, e.g. by a paddle, to move the liquor relatively through the goods. The ability to carry out the

SUBSTITUTE SHEET principal steps of the process in this manner is a significant advantage of the process. The second bath is preferably different from the first bath.

As is known in the art, the goods may be initially made larger than finally desired to allow for predictable shrinkage during the course of the process. This pre-sizing is determined by methods well known in the art, and, especially in the case of completed garments, the proportional over-sizing varies for different parts and dimensions of the garments.

After the pretreatment and before the coating agent application, anhydrous sodium hydrosulphite or other effective neutralising agent is preferably added to the pretreatment bath to neutralise residual pretreatment agent. Excess Crosil salt in the goods masks coating agent application sites because the salt is continuing to react. The neutralising agent should be carefully chosen to avoid damage to dyestuffs on the goods.

The pretreatment bath preferably has a liquor to goods ratio by weight, the liquor being predominantly water, in the range 20:1 to 40:1, most preferably 25:1 to 35:1, and is advantageously maintained at a temperature in the range 25° to 40°C, most preferably 25° to 35°C. Below a ratio of 20:1, the pretreatment agent is exhausted too quickly and unevenly for a satisfactory result, and the goods will not properly move about in the bath. Above a ratio of 40:1, the time to exhaust the pretreatment agent becomes impractically long. The pretreatment proceeds too slowly when the temperature is below 25°C, while unacceptable or unpredictable shrinkage can become a significant risk above 40°C.

On addition of the wetting agent to the pretreatment bath, the bath is agitated for a time sufficient to ensure adequate wetting of the goods before the pretreatment agent is added to the bath. This time is preferably at least 5 to 15 minutes, most preferably 5 to 10 minutes. If Croscour HVT is employed as the wetting agent, it is preferably added in the proportion 2gm/lt of goods to lOgm/lt, most preferably 2.5 - 5.0 gm/lt.

The pH of the pretreatment bath for addition of the wetting agent and the pretreatment agent is preferably in the range 2.5 to 4.0, most preferably 2.7 to 3.2. It is desirable to maintain the bath distinctly acid, as most dyestuffs used on woollen goods are not adversely affected by an acid bath but may be adversely

SUBSTITUTE SHEET affected by an alkaline bath. Moreover, an acid bath enhances the rate of exhaustion of the Crosil salt. Formic acid is the preferred acid for this purpose. Where Crosil salt is employed as the pretreatment agent, and the goods are worsted system goods, it is added in a proportion by weight of goods in the range 4 to 9%, most preferably 6 to 8%. Below 4%, there is inadequate modification of the wool structure. A level above 9% is of no additional benefit and the salt will never be fully exhausted. The bath is preferably agitated after addition of the pretreatment agent until it is substantially exhausted.

Exhaustion of the salt can be followed using starch /potassium iodide papers, a pale blue colouration indicating that the reaction is almost complete.

The neutralising agent is preferably added to the pretreatment bath in the proportion to the goods by dry weight in the range 4 to 9%, most preferably 6 to

8%, while the pH of the bath is preferably raised to a value in the range 6 to 9, most preferably 7 to 8,for example by adding soda ash to the bath. The salt neutralisation is optimally effective at a pH between 6 and 9. The bath is agitated after addition of the neutralising agent for a period of 5 to 15 minutes, most preferably 7 to 12 minutes. Excess Crosil salt in the goods masks polymer application sites because the salt is continuing to react.

After neutralisation of the pretreatment agent, the bath is preferably dropped and the goods transferred to a new coating agent application bath, or a new bath added to the goods. The preferred and most preferred ranges for the liquor to goods ratio, the temperature and the pH are similar to those for the pretreatment bath.

Where Basolan SW is employed as the coating agent, it is preferably added in the proportion by weight of goods in the range 1.5 to 4.0%, most preferably 2.0 to 3.0%. Below 1.5%, there is no effective coating of the goods, while an addition above 4.0% results in incomplete exhaustion and in goods having a slimy handle. It is also preferred to prepare the Basolan SW by dissolving it in 100% sulphuric acid. After the coating application, the goods are preferably rinsed in a bath e.g. tap water, having a liquor to goods ratio by weight in the range 20:1 to 40:1, most preferably 25:1 to 35:1, and a temperature in the room temperature range 15 to

SUBSTITUTE βHEET 25°C, most preferably 17 to 25°C. Rinsing is preferably for about 5 minutes under agitation, the goods are removed and subjected to water extraction and/ or drying. A dye fastening agent may be added at any one or more of the described steps, as required. Example 1

A batch of worsted system "fully fashioned" wool-blend (80% wool 20% nylon) jumpers, 22 stitches per inch, intended for school uniform wear and dyed to this end, was placed in a water bath with a liquor to goods ratio by weight of about 30:1. The bath temperature was about 30°C for the subsequent processing steps in the bath. The wetting agent Croscour HVT was added in the proportion by weight of goods of 3gm/lt, the pH of the bath are lowered by addition of formic acid and maintained at about 3, and the bath agitated for five minutes. Crosil salt was added in the proportion by weight of goods of about 7%, and the bath agitated to substantial exhaust of the Crosil salt. The vessel was free of any internal brass fittings as it is known that Crosil salt migrates to brass in preference to wool.

Soda ash was now added to raise the bath pH to 7 and anhydrous sodium hydrosulphite added, to neutralise the excess Crosil salt, in the proportion by weight of goods of about 7%. The bath was agitated for 10 minutes and then dropped.

A fresh water bath was provided for the pretreated jumpers, again with a liquor to goods ratio of 30:1 and a temperature of about 30°C. The pH was again maintained at about 3. The coating agent Basolan SW, dissolved in 100% sulphuric acid, was added to the bath in the proportion to goods by weight of about 2.5%. The bath was then agitated until the Basolan SW was exhausted.

The second bath was now dropped and a third fresh water rinsing bath provided for the jumpers at a liquor to goods ratio of about 30:1 at room temperature, typically around 20°C. After bath agitation for five minutes, the jumpers were removed, inspected and measured, and placed in a tumble dryer.

It was found that when the jumpers emerged from the dryer, they did not exhibit any noticeable iirther shrinkage or felting.

SUBSTITUTE SHEET The jumpers were then subjected to a cycle of 25 machine washes, after each of which the jumpers were tumble dried. The maximum shrinkage measured in the batch was 3.5%, although the mean shrinkage of most jumpers of the batch was observed to be of the order of 1%.

Example 2

For comparison purposes, a batch of jumpers was manufactured (worsted system) from yarn treated with the Hercosett shrinkproofing process described above. These jumpers were subjected to a similar cycle of 25 machine washes, after each of which the jumpers were tumble dried. All of the jumpers in the batch were observed to shrink by at least 8%, in some cases substantially more.

Example 3

Example 1 was repeated for a batch of worsted system "cut and sew" wool-blend (80% wool, 20% nylon) jumpers. The batch was subjected to the described test cycle of 25 machine wash/tumble dry treatments. The shrinkage of the garments was observed to be in the range 0 to 3.5%.

Example 4

Example 1 was repeated for a batch of worsted system fully fashioned cardigans. The batch was subjected to the described test cycle of 25 machine wash/tumble dry treatments. The shrinkage of the garments was observed to be in the range 0 to 3.5%.

Example 5

Example 1 was repeated for several batches of jumpers similar to those in Example 1 except that the stitch density varied in the range 16 to 24 stitches per inch and that the wool content was variously 100% and 80%. The batches were

SUBSTITUTE SHEET subjected to the described test cycle of 25 machine wash/tumble dry treatments. The shrinkage of the garments was observed to be in the range 0 to 3.5%.

Example 6

Example 1 was repeated for a batch of woollen system pure wool jumpers. The batch was subjected to the described test cycle of 25 machine wash/tumble dry treatments. The shrinkage of the garments was observed to be in the range 0 to 3.5%.

SUBSTITUTE SHEET

Claims

1. A process for enhancing the shrinkage and felting resistance of wool or woollen goods, comprising the steps of: a. subjecting the wool or woollen goods to a predominantly oxidising pretreatment with a pretreatment agent which is a salt of preoxymonosulphuric acid; and b. applying to the fibres of the thus pretreated wool or woollen goods a fibre coating agent which is a polyether substituted with aziridine groups.

2. A process as claimed in Claim 1, wherein said pretreatment agent is an alkali metal salt of peroxymonosulphuric acid.

3. A process as claimed in Claim 2, wherein the alkali metal is potassium.

4. A process as claimed in claim 3, wherein said pretreatment agent is Crosil salt.

5. A process as claimed in any one of the preceding claims, wherein said the coating agent is a compound of the general formula (I):

wherein R¹ to R⁷ are identical or different and are hydrogen or alkyi radicals of 1 to 4 carbon atoms, Q is the radical obtained by removal of the hydrogen atoms of N hydroxyl groups from an n-hydric alcohol or phenol, n is 2 or 3 and X is a

SUBSTITUTE SHEET polyether chain of oxybutylene units and/or oxypropylene units with or without oxyethylene units, said polyether chain having a C:0 atomic ratio of not less than 2.67:1 and a molecular weight from 150 to 1,500 if n = 2, and from 150 to 3,000 if n = 3.

6. A process as claimed in any one of the preceding claims, wherein said coating agent is Basolan SW.

7. A process as claimed in any one of the preceding claims, further comprising adding a wetting agent is added to the wool or woollen goods prior to step (a).

8. A process as claimed in claim 7, wherein said wetting agent is Croscour HVT (Registered Trademark).

9. A process as claimed in Claim 7 or Claim 8, wherein said wetting agent is added in the range of 2gm/lt to lOgm/lt of goods.

10. A process as claimed in any one of the preceding claims, wherein the liquor to goods ratio by weight in step (a) is in the range 20:1 to 40:1.

11. A process as claimed in any one of the preceding claims, wherein the temperature during step (a) is 25 ° to 40 °C.

12. A process as claimed in anyone of the preceding claims, wherein the pH during step (a) is 2.5 to 4.0.

13. A process as claimed in any one of the preceding claims, wherein said the pretreatment agent is added in an amount of 4 to 9% by weight of goods.

14. A process as claimed in anyone of the preceding claims, wherein a neutralising agent is added after step (a) but before step (b).

SUBSTITUTE SHEET

15. A process as claimed in Claim 14, wherein said neutralising agent is anhydrous sodium hydrosulphite.

16. A process as claimed in claim 14 or claim 15, wherein said neutralising agent is added in an amount of 4 to 9% by weight of goods.

17. A process as claimed in any one of claims 14 to 16, wherein the pH during application of the neutralising agent is 6 to 9.

18. A process as claimed in any one of the preceding claims, wherein said coating agent is added in an amount of 1.5 to 4.0% by weight of goods.

19. A process as claimed in any one of the preceding claims, wherein after step (b) the goods are rinsed in a bath having a liquor to goods ratio by weight in the range 20:1 to 40:1.

20. Wool or woollen goods when treated according to the process of any one of the preceding claims.

21. Wool or woollen goods, and processes for their treatment, substantially as hereinbefore described with reference to any one of the examples.

SUBSTITUTE SHEET