JPS6117947B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in the processing of wool to provide non-yellowing and shrinkage resistance to the wool, and in particular to improvements in the processing of wool, which can be made into continuous lengths or which can be easily combined to form continuous lengths and which provide substantially uniform processing. The present invention relates to a method for treating materials made of or containing wool that can receive wool. Wool materials available in continuous length include yarns made of or containing wool, tops and woven or knitted fabrics. Such elongated articles may be formed by sewing knitted garments such as socks and then separated after processing is complete. A major disadvantage of wool is that it shrinks when washed, and for many years treatments have been used to make wool resistant to shrinkage. Among the well-known processing agents for such processing are materials that create free chlorine in solution, such as monopersulfuric acid and hypochlorite and dichloroisocyanurate. Monopersulfuric acid and sodium dichloroisocyanurate have always had the disadvantage of being rather expensive, and this disadvantage has become increasingly severe in recent years. The present invention seeks to overcome this difficulty by using hypochlorites (alkali metal or alkaline earth metal hypochlorites). It is known that the reaction rate between hypochlorite and wool varies inversely with the pH of the solution, and is extremely rapid in acidic solutions. Batch processing of wool is carried out by gradually adding hypochlorite to a stirred acid solution in which the wool is soaked. Economically viable continuous wool processing methods always involve immersing the wool in a large bath, such as a backwasher. Large baths of acidic hypochlorite are unpleasant to workers because they emit unpleasant odors and require constant monitoring of chlorine content, oil buildup, and other factors. Continuous treatment of wool with alkaline hypochlorite under controlled conditions was proposed in 1946 by Milton Harris et al. in British Patent No. 621,989. Harris et al. specifically note that the wool is contacted with a hypochlorite solution at a pH of 7.5-10 for less than 1 minute, followed by immediate removal of the hypochlorite from the material. This process gave wool a shrinkage resistance that passed the fairly relaxed standards put in place after the war, and was in fact used industrially for several years. This process was eventually superseded in 1950 by other methods, including the monopersulfuric acid process. This method also provides similar shrinkage resistance and produces whiter wool as the Harris et al. method, but to the best of our knowledge it has not been used since then. Shrink resistance standards have now become even more stringent due to the increased use of domestic washing machines to wash wool-containing clothing. Meanwhile 1960
In 2013, clothing containing wool was made with a liquid ratio of 25:1.
Wool is considered to have acceptable shrinkage resistance if it passes the Cubex test for hours, and the current relevant Cubex test is as established in IWS test method 185. It takes 3 hours at a liquid ratio of 15:1. This test has been used unless otherwise noted to yield the results reported in this specification. IWS test method 185 is at least 10% of the previous standard
It's twice as bad. It is well known that wool samples, which are shrink resistant when subjected to repeated gentle washings, can shrink excessively once subjected to more severe washing conditions. Further, US Pat. No. 3,076,690 (which corresponds to Japanese Patent Publication No. 32-3350) is known as a method of making wool shrink resistant. However, in this method, as shown in the comparative experiment example detailed later, the above IWS
Does not pass Test Method 185. It has traditionally been believed that the best conditions for alkaline chlorination using sodium hypochlorite are achieved at a pH of 8.5-9.0, but that only very limited shrinkage resistance is obtained. was. The industrial scale working conditions of Harris et al. gave results consistent with this perspective. The inventors have found that if the best conditions for uniform application of hypochlorite solution to wool within a certain pH range are achieved, i.e. by using a precision padded mangle, no yellowing occurs. It has now been found that very high shrinkage resistance standards can be obtained that meet the stringent criteria mentioned above. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for treating wool to impart non-yellowing and shrinkage resistance to a continuous length of wool, the method comprising: (a) horizontally opposed rollers of precision padded mangles; Wetting agent and available chlorine at pH 5-8 in bath
A hypochlorite solution containing 0.5-5% by weight is made; (b) the wool is passed through the solution in the bath and immediately thereafter through the nip of the padded mangle, so that the wool contains 85-160% of its weight; The residence time of the solution in the bath should not exceed 15 minutes, and the time from the first contact of the wool with the solution in the bath until the wool passes through the nip of the padded mangle should exceed 3 seconds. (c) further processing the treated wool; (d) maintaining the concentration and composition of the solution in the bath by continuous or intermittent addition of freshly mixed solution, comprising: Chlorite is the only oxidizing agent used in step (a) above to provide shrinkage resistance, and step (c) above is the process by which the wool shrinks over 3. It consists of dechlorinating and washing the treated wool by immersing it in an acid with no PH. The data presented in the table below shows that gentle washing standards such as those used 20 years ago can be achieved by implementing the method in the PH range of 7.5-10. The solution contained 3% by weight of available chlorine.

[Table] 10% area shrinkage is an acceptable upper limit. There is no significant difference between the 4.6% and 0.7% indices obtained at the 25:1 liquid ratio for 30 minutes. These samples suffered worse shrinkage when subjected to the more severe test treated with PH9, whereas PH9
A surprising result was that samples treated with 7.8 produced acceptable results. The hypochlorite solution is therefore maintained at a pH of 5-8, preferably 6.5-8, most preferably 7.5-7.8. When the pH of the solution increases more than 8, the shrinkage resistance drops extremely as shown in the table below, the data in the table below is 2.25%.
was obtained using a solution containing available chlorine.

[Table] The lower end of the PH range was determined by necessity to control the reaction between chlorine and wool; it is PH dependent and increases with decreasing PH value. If the reaction occurs too quickly, the wool cannot be processed evenly. The inventors are PH
We have found that within the range of 7.5 to 7.8, this method is easily adjustable and the wool is uniformly treated. When using a buffer to adjust the PH of a hypochlorite solution, it must be a buffer that is stable to chlorine, such as sodium hydrogen phosphate, but there are no strict regulations on the type of buffer. Hypophosphorous acid is a weak acid. (dissociation constant 3×10 ¹⁸ ), sodium hypophosphite/hypophosphorous acid can be used as a buffer. In this case 6.5-8.0
It is only necessary to add the required amount of acid to obtain a buffered PH of . The inventors have discovered that the mixture
It has been found that it can be successfully operated using a mixture of sodium hypochlorite and a mineral acid such as phosphoric acid, hydrochloric acid or sulfuric acid such that the pH value is below 8.
The advantage of this method is the simplicity and low cost of solution preparation. Rapid wetting of the wool is an essential requirement and the solution contains a wetting agent which should be stable to the hypochlorite solution under the conditions used during processing. Although there are no strict regulations regarding the type of wetting agent, for best performance it is desirable that an average settling time of less than 5 seconds be obtained in the test described below (settling test). Two solutions are prepared at 25°C, one containing available chlorine (50 g/) and the other containing sodium dihydrogen phosphate (45 g/) and a wetting agent. Mix 100 c.c. of each of the two solutions and check the PH, it should be in the range of 7.5-7.8. 64 small tufts of untreated wool (0.18 g: 3 cm long) of a quality containing less than 1% oil are placed on the surface of the solution within 1 minute of mixing, until the wool disappears below the surface. Measure the time required.
Repeat this method 4 times using new solution each time.
Calculate the average settling time. Next, the average settling time is measured in the same manner using a solution that has been left to stand for 15 minutes after mixing. Dialkyl sodium sulfosuccinates, especially dihexyl and dioctyl sodium sulfosuccinates, satisfy these specifications and therefore the present invention prefers to use these materials in this method, the wetting agent in an amount of 0.1 to 2% by weight of the solution. It is preferable to use it in The rate of wetting of the wool is then faster than the rate of reaction between the wool and hypochlorite, so that the reaction occurs uniformly and is not limited by the surface area of the top. This solution is provided in the form of a small volume bath formed by two rollers forming the nip of a horizontal precision pad mangle. The wool is passed through this solution and through the nip of the padded mangle. The opening of the padded mangle allows the wool to absorb the solution by 85% of the weight of the wool itself.
Regulate the carrying progress by %~160%, preferably 100%~150%. When the impregnation rate is less than 85%, the capillary effect may cause a heterogeneous reaction between the wool and chlorine. More than 160% is difficult to achieve, suffering from excessive loss of solution through the nip of the pad mangle. The residence time of the solution in the bath does not exceed 15 minutes, preferably 2-3 minutes. The short residence time protects the solution from long-term changes in composition, otherwise the deposition of oil from the wool or the reaction between the wool and hypochlorite in the bath or the hypochlorite Compositional changes result from the accumulation of salts resulting from decomposition. The speed of passage of the wool is such that the time from initial contact of the fibers with the solution in the bath to the time of passage of the fibers through the nip of the padded mangle does not exceed 3 seconds. 5 to 120 seconds after passing through the nip of Patsdomangle,
The wool is immersed in the acid, preferably for 10 to 30 seconds. If soaked too quickly, the adsorbed hypochlorite solution will not have enough time to react with the wool. If soaking is prolonged too long or omitted entirely, the wool becomes yellowed and becomes economically unacceptable. The treated wool is passed through a solution of strong mineral acids such as sulfuric acid, hydrochloric acid, or phosphoric acid, keeping the pH at no greater than 8, preferably no greater than 2. Typically, a bath containing 10 g/l of sulfuric acid is prepared and a stronger solution of sulfuric acid (eg 50 g/l) is fed into this at a rate such that 3 parts of sulfuric acid are passed for every 100 parts of wool passing through the bath. Under these conditions, the wool after dechlorination and washing contains 1.5-2.5% sulfuric acid,
Has good color. If less acid is used,
Therefore, if the treated wool contains 0.5% or less sulfuric acid, the wool will be yellow. Yellowing appears with increasing bath PH, so wool is best treated at a PH not greater than 3. As used by Harris et al. for dechlorination, the pH of an aqueous solution of bisulfite is at least
A good value is 4.5. After passing through the acid bath, the wool must be passed through another bath (eg bisulphite) for dechlorination. However, the use of an acid bath followed by a bisulfite bath stops the reaction with the hypochlorite and leaves the wool whiter than using only a bisulfite bath to dechlorinate the wool. Preferably, the acidified wool is allowed to remain for 2 minutes or less before further processing. Dechlorination and washing of treated wool is a standard step in anti-shrink treatment. The concentration and composition of the hypochlorite solution in the bath are:
The bath is maintained by continuously or intermittently adding freshly mixed solution. It is important to mix this replenishment solution fresh, because at a pH below 8, hypochlorite decomposes rapidly and
Lose chlorine. We have prepared (i) an aqueous hypochlorite solution having a pH of at least 10, conveniently its own pH, containing twice the desired amount of available chlorine, and (ii) twice the desired concentration of available chlorine. It has been found preferable to mix equal volumes of aqueous solutions of acid or buffer. The wetting agent may be contained in any solution, but is preferably contained in an acid or buffer. The streams of both liquids are metered into the mixing vessel by flow meters regulated by needle valves and then added directly to the treatment bath. In normal operations, flow adjustment with flow meters provides satisfactory results under industrial conditions. Some anti-shrinkage processing methods that use the principle of mixing both solutions in a constant ratio are very sensitive to small changes in that ratio, but the method described here is suitable for use with metering valves such as It has the advantage of being self-compensating to some extent against temporary local failures. (A) When the metering valve for hypochlorite is partially blocked, the fluid mixture leading to the treatment bath will contain less chlorine and the PH will be lower, thus allowing the chlorine to react more violently with the wool. become. (B) When a metering valve for a buffer or acid solution is partially occluded, the fluid mixture communicating with the processing bath is
The pH increases and it contains more chlorine due to reaction with wool. By precision padded mangle is meant a padded mangle in which the squeezing pressure of the opposing rollers can be varied to adjust the amount of liquid uptake by the wool.
Such precision padded mangles are normally used under conditions where no appreciable reaction between the wool and the treatment solution occurs in the bath. In the process of the invention, the significant reaction between the hypochlorite and the wool takes place in the bath (although most of the reaction occurs within the wool sliver after the wool passes through the nip between opposed rollers and leaves the bath). ). The manner in which the liquid is added to the bath is therefore of particular importance in the present invention. Most pads are suitable for concentration control operation between high and low concentration values by controlling the supply valve. When there is too much separation between high and low concentrations, the liquid concentration can become dry and variations in throughput depending on the length of the sliver (as well as opening and closing of the liquid supply) are found. . It is important for best performance that the interval between liquid applications not exceed about 5 seconds. Furthermore, it is an essential requirement that the feed liquid be distributed very uniformly over the pad;
The inventors have found that two spray pipes placed on each side of the wool web, but adapted to spray directly onto the wool, can accomplish this. Example 1 Continuous lengths of wool tops each weighing 20 g/m
10 bottles, available chlorine from sodium hypochlorite
2.25% by weight of an anionic wetting agent, which is a mixture of secondary alkyl sulfates and linear alkylbenzene sulfonates, and 2% by weight of sodium dihydrogen orthophosphate.
Passed through a 4.5 volume bath. This solution had a PH of 7.7. After passing through the solution, the wool was introduced into a precision nip in which the impregnation of the solution was adjusted to 130% by weight of the wool. The wool speed was 6 m/min, where 1200 g of wool was passed through the bath and nip every minute, consuming 1560 ml of the treatment solution. The bath contains (i) 780 ml per minute of a solution containing 4.5% by weight of available chlorine from sodium hypochlorite with a PH of 12.1, and (ii) the anionic wetting agent described above with a PH of 5.0. 78.0 ml per minute of a solution containing 1.5% by weight and 4% by weight of sodium dihydrogen phosphate was metered out and kept full. Mixing was carried out immediately before introduction into the processing bath. After passing through the nip, wool loses 1% within 30 seconds.
sulfuric acid solution, followed after 2 minutes by (i) a wash bath of warm running water, (ii) a 5% sodium bisulfite solution, and (iii) two consecutive water washes. The wool was then dried by passing it continuously through a drying chamber. Samples of treated and untreated wool tops were spun into 2/24 (worsted) yarn and submitted to IWS Test Method 185. % Shrinkage Area Untreated Control Sample 66.9 Treated Material 0.9 The wetting agent used in this experiment did not satisfy the 5 second sedimentation test described above. Thus, while this method worked well on the fairly small scale used for the experiments, it did not work as well on the large scale. Example 2 Example 1 was carried out using the following aqueous solution and replenishment solution in place of the aqueous solution and replenishment solution used in Example 1.
repeated. Aqueous solution: 2% available chlorine from sodium hypochlorite, 2% sodium dihydrogen phosphate, 0.3% dioctyl sodium sulfosuccinate, PH 7.7. Replenishment solution: (i) 780 ml/min of a solution containing 4% available chlorine from sodium hypochlorite with PH 12, and (ii) 4% sodium dihydrogen phosphate and 0.6 dioctyl sodium sulfosuccinate with PH 5.
% solution containing 780ml/min. The obtained areal shrinkage test results were as follows. % Area Shrinkage Untreated Control Sample 66.9 Treated Material 6.6 Example 3 The method of Example 2 was repeated except that sodium dihydrogen orthophosphate was replaced with sulfuric acid. The bath contained 0.8% by weight sulfuric acid and had a pH of 7.6. The bath was kept full by measuring a mixture of the following two solutions into the bath. (i) 780 ml/min of a solution containing 4.5% available chlorine from sodium hypochlorite with a pH of 120. (ii) 780 ml/min of a solution containing 0.6% dioctyl sodium sulfosuccinate wetting agent and 1.6% sulfuric acid with a pH of 0.9. A sample of the fully treated top was spun into 2/24 yarn (worsted) and subjected to IWS Test Method 185. The area shrinkage rate was 1.2%. Example 4 The following aqueous solution and replenishment liquid were used in place of the aqueous solution and replenishment liquid used in Example 1, and the weight of wool was
Example 1 was repeated using a solution pick-up rate of 105%. Aqueous solution 2.25% available chlorine from sodium hypochlorite,
Sodium dihydrogen phosphate 2%, anionic wetting agent
0.45% (this is a mixture of primary alkyl sulfates, linear alkyl benzene sulfonates and dialkyl sulfosuccinates), PH 7.6. Replenishment liquid (i) 630 ml/min of a solution having a pH of 12 and containing 4.5% available chlorine of sodium hypochlorite. (ii) PH5.0, 4% sodium dihydrogen phosphate
and 630 ml/min of a solution containing 0.9% of the above anionic wetting agent. After passing through the precision nip, the wool was divided into three parts. The first part was passed within 30 seconds into a bath containing an acidic solution. The second part is 90°C before passing into the acidic solution.
I left it for a second. The third part was left for 5 minutes before acidification. After acidification, the tops were treated with 5% sodium bisulfite solution, washed with water, dried and then gilled several times. One sample of the above tops was passed through a sodium bisulfite solution without acidification. Each of the four separate treatments was carried out in the following acid solutions. (i) 1% sulfuric acid, PH1.6 (ii) 1% formic acid, PH2.5 (iii) 1% acetic acid and sodium acetate, PH3.4 (iv) 1% acetic acid and sodium carbonate, PH4.9 Top color were evaluated using the Kollmorgen Color Eye KCS-18 using the standard ANLAB color difference equation [which is recommended by The Color Measurement Committee of The Society of Dyers and Colorists]. Ori,
(JSDC, Vol. 80, p. 368, 1970), and was subsequently adopted by The International Standards Organization in 1972]. One sample of finely colored wool top was used as a standard against which each treated sample was compared. In the table below showing the results, each symbol has the following meaning. L = depth of color; + light, - deep A = color difference; + reddish, - greenish B = color difference; + yellowish, - bluish A color difference of 0.5 unlove units can be just detected by the eye. .

[Table] No acidification There was an excellent correlation between visual judgment and unlove reading, especially for positive values of B, which is a measure of yellowing. The following conclusions were drawn from the above results. (a) Acidification step is essential to prevent yellowing. (b) Weak acids that give a pH of 5 are not very effective in improving. (c) Strong acids such as formic acid at PH 2.5 give much improved color, especially with short residence times (30 seconds). (d) Best results are obtained when using strong mineral acids with a pH below 2 and minimizing residence time. As mentioned above, a method known prior to the present invention for improving the shrinkage resistance of wool was disclosed in U.S. Pat.
No. 3076690 (corresponding to Japanese Patent Publication No. 32-3350) is known, but this method does not sufficiently achieve shrinkage resistance and prevention of yellowing. This will be demonstrated in the following comparative experimental example. Comparative Experimental Example 1 Experiment 1: This experiment was conducted under conditions as close as possible to those described in Example 1 of Japanese Patent Publication No. 32-3350. It was necessary to construct a special rig for the chlorination step in order to match the liquid ratio and residence time, since in the conventional commercially available backwash design, the liquid/wool ratio required in the bath This is because it was impossible to achieve this ratio. In Example 1 of Japanese Patent Publication No. 32-3350, there is no mention of controlling the volume of the acid solution conveyed from the first step (acid treatment) to the second step (chlorination treatment), but the pH of the chlorination bath A certain amount of carryover is necessary to maintain a reasonably constant value. A constant carryover of the acid solution can be maintained by passing the acidified sliver through the nip roller as the wool exits the bath of the first step. To establish the optimum conditions for steady state in the second step chlorination bath, different amounts of acid solution carryover were used and corresponding changes in the volume and strength of the sodium hypochlorite solution feed ratio were used. After conducting a preliminary experiment, the next experiment was conducted. 1st step (acid treatment) 4 wool tops (sliver weight 20g/m)
continuously at a speed of 1 m/min, 2.2% formic acid solution and 0.5% wetting agent (Targitol TMN-6)
was passed through a bath containing . The pH of the bath is 2.2,
The residence time of the wool in the liquid was 29 seconds. Total volume is 75
It was hot. After exiting the bath, the wool was passed through a pair of nip rollers to give a liquid content of 150-160% based on wool weight. 2.2% for bathing during transportation
Formic acid solution was replenished at a feed rate of 130 ml/min. 2nd process (chlorination treatment) Acid treated sliver is 56cm long at 1m/min.
continuously passed through the trough. A sodium hypochlorite solution with a pH of 9.6 containing 0.15% available chlorine was continuously poured into the trough at its entry point onto the sliver at a rate of 1.5/min (liquid/wool ratio of the feed solution).
20:1). This corresponds to an amount of 2.8% chlorine in wool. The volume of the trough was 2, which corresponded to a liquid/wool ratio in the bath of 25:1. An overflow was provided at the opposite end of the wool entry point to keep the wool submerged during its passage through the trough. The pH of the bath solution was 3.5 during feeding. 3rd step (dechlorination treatment) The chlorinated wool is then immediately treated at 2% at 1 m/min.
Passed through a bath containing a solution of anhydrous sodium sulfite. The contact time with the liquid was about 35 seconds. Fourth step (neutralization water washing treatment) The sliver was passed through a running water washing bath, and then passed through a pair of nip rollers and a hot air dryer. Experiment 2 (invention): The same sliver used in Example 1 above was treated according to the method of Example 3 above with slight modifications. The treatment bath contained 2.25% available chlorine from sodium hypochlorite, 0.775% sulfuric acid, and 0.3% sodium dioctyl sulfosuccinate, with a pH of 7.4.
It was hot. The acid supply solution contained 1.55% sulfuric acid instead of the 1.6% sulfuric acid in Example 3 above. The content (absorption rate) of the treatment solution was 11.7%, which corresponded to an amount of 2.63% chlorine based on wool. The wools of Experiments 1 and 2 above were comparatively evaluated for shrinkage resistance and anti-yellowing properties. Shrinkage resistance: 2/24 of the tops treated in experiments 1 and 2 above.
(worsted) yarn and tested for shrinkage resistance according to IWS test method 185. A separate untreated wool sample was also tested as a control. The results are shown below.

Table: As is clear from the above data, the area shrinkage for the wool of Experiment 1 was only slightly better than that of the untreated control wool. However, the wool of experiment 2 according to the invention shows excellent shrinkage resistance even when tested to the very harsh standards of IWS test method 185. We believe that the primary reason for this extreme difference in shrinkage resistance between Runs 1 and 2 is the effectiveness of the chlorination treatment. Stain testing of the loosened tops showed that the wool treated according to experiment 1 had a very uneven chlorination, whereas the wool treated according to experiment 2 had a very uniform chlorination. However, the wool used in Experiment 1 was
It had reasonable shrinkage resistance when tested under the very loose standards in use in 1955, when the application was filed. To investigate this, wool samples treated in Experiment 1 were subjected to Dylan Normal and
Tested using a loose shrink resistance standard known as Dylan Severe. The tests were carried out for 30 and 60 minutes, respectively, at 40°C and 25°C in a PH7 buffer.
It was carried out on a cubex machine with a liquid ratio of 1. The results were as follows.

[Table] Therefore, this material passed the normal test (the maximum allowable area shrinkage rate is 10%) but failed the severe standard. Products made from such wool could only be washed by hand with very gentle agitation. In contrast, the previously used IWS test method
185 was carried out for 180 minutes at a liquid ratio of 15:1, and
It is 20 times more severe than the normal exam. Yellowing: The wool treated in Experiments 1 and 2 was evaluated for color using the method described in Example 4. The color of the wool was evaluated using the Umbra color method and Kollmorgen Color Eye KCS-18. A sample of finely colored wool top was used as a reference standard against which the treated wool was compared. The results are shown in the table below.

[Table] +B value indicates yellowing. When compared with the naked eye,
The tops from Experiment 1 were noticeably more yellow than the tops from Experiment 2, this data was also confirmed by the data in column B above. Conclusion: The wool samples from Experiment 1 (based on the method of Japanese Patent Publication No. 32-3350) and the wool samples from Experiment 2 (based on the method of the present invention) are based on the shrinkage resistance and yellowing data above. This shows that it satisfies new standards and is superior to Experiment 1. Wool treated with the method of Experiment 1 has only a low degree of shrinkage resistance, meeting only the standards required around 1955 (Showa 30), but not the harsh current standards. . In addition, the method is also inferior to the method of the present invention in terms of yellowing. The reason for this is that if hypochlorite is uniformly applied to wool under acidic conditions, good shrinkage resistance can be expected without significant yellowing. However, when used under acidic conditions as in Experiment 1, the reaction becomes so fast that uniform application of hypochlorite cannot be achieved.
As a result, shrinkage resistance becomes poor. Experiment 2 applied the hypochlorite under neutral conditions, thus ensuring a more gradual and uniform application. However, the disadvantage of using neutral conditions is that it causes yellowing of the wool. However, in this case, this problem could be overcome by subsequent acid treatment.

Claims (1)

[Scope of Claims] 1 (a) A hypochlorite solution containing a wetting agent and 0.5 to 5% by weight of available chlorine at a pH of 5 to 8 is placed in a bath equipped with horizontally opposed rollers of a precision padded mangle, and ( b) Single treatment of a continuous length of wool in a bath to wet the wool with the solution in solution, immediately after which the wool is passed through the nip of the padded mangle, so that the wool absorbs 85-160% of its weight in solution. At this time, the residence time of the solution in the bath should not exceed 15 minutes, and the residence time of the wool in the bath should not exceed 3 seconds; (d) continuously or intermittently adding freshly mixed solution to the bath to maintain the concentration and composition of the solution in the bath; In a wool treatment method for imparting shrinkage resistance to a continuous length of wool, hypochlorite is the only oxidizing agent imparting shrinkage resistance used in step (a) above, and (c) The process is to reduce the pH of the wool to no more than 3 within 5 to 120 seconds after the wool leaves the nip of the padded mangle.
1. A method for treating wool, which comprises immersing the treated wool in an acid having the following properties, dechlorinating the treated wool, and washing the treated wool. 2. The method according to claim 1, wherein the hypochlorite solution has a pH of 7.5 to 7.8. 3. The method according to claim 1 or 2, wherein the hypochlorite solution contains sulfuric acid and sodium phosphate as pH lowering agents. 4. The method according to any one of claims 1 to 3, wherein the hypochlorite solution contains 0.1 to 2% by weight of dihexyl sodium sulfosuccinate or dioctyl sodium sulfosuccinate as a wetting agent. 5. The method according to any one of claims 1 to 4, wherein the residence time of the solution in the bath is 2 to 3 minutes. 6. The method according to any one of claims 1 to 5, wherein the time for soaking the wool in the acid in step (c) is 10 to 20 seconds after leaving the padded mangle. 7 Hypochlorite solution (i) an aqueous hypochlorite solution containing twice the desired amount of available chlorine at its native pH, (ii) an acid or buffer and a wetting agent, each at twice the desired concentration. 7. A method according to any one of claims 1 to 6, wherein both solutions are measured in equal volumes and placed in a mixing vessel, and then directly placed in the treatment bath.