JPS6317948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in wool processing to impart shrink-proof properties to wool, particularly wool that is available in continuous lengths or that can be easily joined to form continuous lengths and thus substantially The present invention relates to the treatment of materials made of or containing wool that can be subjected to uniform treatment. Wool materials available in continuous length include yarns, tops and woven and knitted fabrics consisting of or containing wool. Such continuous lengths may be formed by sewing articles of clothing, such as socks, which are then separated after processing is complete. More particularly, the present invention provides a method for preshrunk treatment of wool comprising the use of aqueous solutions of permanganates, alkali metal salts such as potassium permanganate, and hypochlorites such as sodium or calcium hypochlorite. Regarding the law. This combination of oxidizing agents has been known for many years, for example British Patent No. 1,073,441 provides a method for continuously preshrunk wool using solutions of these agents at pH 5-10. This does not teach that PH is a requirement that requires strict regulation, and Example 2
The pH of the solution used was 9.3. One aspect of the present invention is the discovery that unexpectedly improved results are obtained when the pH of the oxidizing solution is carefully controlled within a specified range. In recent years, shrinkage prevention standards have become increasingly strict.
This is partly due to the increased use of domestic washing machines to wash clothing containing wool. In the 1960s (section of UK Patent No. 1073441 above), clothing containing wool was classified as:
Cubex test for 1 hour at a liquid ratio of 1
It was considered to have acceptable shrink resistance if it passed the International Wool Secretariat (IWS) test method 192. It currently takes 3 hours at a liquid ratio of :1. This test is used to obtain the results reported in this specification. IWS test method 192 is probably at least 10 times more stringent than its predecessor. Wool samples that are shrink resistant when subjected to repeated normal gentle washing may undergo extreme shrinkage when exposed to more severe washing conditions even once. British Patent No. 1475367 describes the IWS test method.
A method is described for preshrunk wool in such a way as to pass 192, which consists of two main steps: (a) treatment with hypochlorite at pH 5-8, the upper limit of this range being and (b) soaking the wool in acid at a pH not higher than 4 for less than 2 minutes after treatment with hypochlorite; the purpose of this step is to The purpose is to prevent burns; Although this method provides the desired shrink resistance, it has various drawbacks as described below. (1) Acid treatment is an extra step that can be omitted. (2) The acid step requires washing and neutralization of the wool, which is time and cost consuming. (3) The wool texture is less soft than desired. A further feature of the invention is the discovery that these drawbacks can be overcome by using permanganate in conjunction with hypochlorite. However, the use of permanganate in this method introduces its own difficulties. Continuous preshrunk treatment of wool is usually carried out using precision padded mangles, in which the treatment bath is contained by two horizontally opposed rollers and pressure pads at each end, and the wool to be treated passes through the bath. Passing downwardly through the nip between the rollers, the processing liquid is continuously metered into the bath in response to the liquid level in the bath. This treatment liquid is unstable and must be mixed only immediately before use. This is accomplished by mixing equal volumes of two stable liquids containing each component of the processing solution in a see-through tank (mixing vessel). Variations in wool processing conditions require frequent adjustments to the rate of metering of liquid into the fluoroscopic tank. Float-in-glass flow meters are ineffective with opaque solutions such as permanganate. The inventors have tried several types of magnetic flowmeters. They have a tendency to develop errors due to even slight corrosion of the inner metal surface, and hypochlorite/permanganate mixtures have the effect of damaging the quality of the steel very quickly. Become. The inventors have also tried variable stroke piston pumps, but have found that these often require significant adjustment to maintain the desired flow. Another aspect of the invention is the discovery of a method for controlling the flow of processing chemicals into the processing bath. The present invention therefore provides a method for imparting shrink-proof properties to wool, which method comprises: (a) mixing aqueous liquid feeds from at least two feed vessels in a mixing vessel;
6.7 to 7.7 to form an aqueous solution consisting of hypochlorite, permanganate and wetting agent, with the supply of aqueous liquid from each supply vessel continuous and responsive to the liquid level in the mixing vessel. (b) transfer the aqueous solution from the mixing vessel to a bath containing horizontal opposed rollers of a precision padded mangle, and cause the transfer to be caused by the rollers to transfer the aqueous solution contained in the bath; (c) wetting the continuous length of wool by successively passing it through the solution in the bath and immediately thereafter through the nip of the padded mangle; , thus ensuring that the wool carries 85-160% of its weight in solution, ensuring that the residence time of the solution in the bath is no longer than 15 minutes, and ensuring that the residence time of the wool in the bath is no longer than 3 seconds. It consists of a process that should not be too long. The pH of the aqueous solution used to treat wool is 6.
-7.7, preferably 7-7.6. When the pH exceeds 7.7, the achieved shrink resistance rapidly deteriorates as shown in the Examples below. The lower limit of the PH range is determined by the need to control the reaction of the oxidizing agent with the wool, which is determined by the PH and increases as the PH value decreases. If the reaction is too rapid, the wool may be processed unevenly. With a PH range of 7.4-7.6, this method is easily controlled and the wool is processed uniformly. It is an essential requirement that the wool is wetted quickly and that the solution consists of a wetting agent that must be stable to hypochlorite and permanganate under the conditions used in this method. be. The rate of wetting of the wool should be faster than the rate of reaction of the wool with the oxidizing agent, so that the reaction occurs uniformly and is not confined to the surface area of the top or other material being treated. . There are no strict restrictions on the type of wetting agent, and nonionic agents such as ethylene oxide condensates have been found to be satisfactory. Preferably, the wetting agent is used in an amount of 0.1 to 2% by weight of the solution. It is generally convenient to use 0.5 to 3% by weight of available chlorine of hypochlorite and 0.5 to 3% of permanganate, such as potassium permanganate, based on the weight of the aqueous solution. Controlling the PH of aqueous solutions can be done by buffers that are stable to oxidizing agents. However, the use of buffers is not necessary and proper control of PH can be easily achieved using the required concentration of acids such as phosphoric acid, hydrochloric acid, acetic acid or sulfuric acid. The aqueous solution is applied in a small volume bath constituted by two rollers forming the nip of a horizontal precision pad mangle. The wool passes downwardly through this solution by the nip of the pad mangle, the opening of which restricts the wool to carry a solution of 85 to 160% of its own weight, preferably 100 to 150%. When absorption is less than 85%, capillary effects cause uneven distribution of the oxidant in the wool, resulting in uneven processing. Achieving more than 160% absorption is difficult and suffers from excessive loss of solution through the nip of the pad mangle. The residence time of the solution in the bath should be no longer than 15 minutes, preferably 2 to 3 minutes. The short residence time protects the solution from long-term changes in composition that occur as a result of oil deposition from the wool or reaction of the oxidizing agent with the wool in the bath or accumulation of decomposition products of the oxidizing agent. The speed of passage of the wool is such that the time from the initial contact of the fiber with the solution in the bath to the time the fiber passes through the nip of the padded mangle is not more than 3 seconds. After passing through the nips of the padded mangle, the wool is kept for a sufficient period of time to ensure that it reacts with the oxidizing agent in the aqueous solution in which it is impregnated.
A time period of seconds to 10 minutes is suitable. The reaction-treated wool is subjected to the usual post-treatments, dechlorination in sodium bisulfite solution, washing and drying. The level and composition of the aqueous solution in the bath is maintained by continuously adding fresh mixed solution thereto. It is important that this replenishment solution be freshly mixed, because at a pH below 8, hypochlorite decomposes and loses chlorine very rapidly. The present invention comprises (i) hypochlorite and permanganate at twice the desired concentration (this mixture is stable at its naturally alkaline PH), and (ii) an aqueous solution of acid or buffer. It is preferable to double the desired concentration and mix the same volume. Preferably, the wetting agent contains an acid or a buffer. The two liquid streams are metered into a viewing tank or mixing vessel and are introduced directly into the treatment bath. Referring to Figure 1 in the accompanying drawings, equal volumes of liquid are metered from two tanks 1 and 2 into a see-through tank 3 and from there a solenoid valve 4.
into the precision pad mangle 5 through. Tanks 1 and 2 are kept full by pumps from storage tanks (not shown) at ground level, with overflow piped back to the storage tanks. The bath through which the wool passes for treatment is a reservoir between a pair of rollers forming the nip of a horizontal precision padded mangle, the roller ends being contacted by a pair of pressure plates containing liquid. The liquid level between the rollers is monitored by a liquid level sensor (not shown) which provides an electrical signal to a solenoid operated valve 4 which controls the supply of processing liquid to the pad mangle. The supply of liquid to the transparent tank 3 is controlled by needle valves 6 and 7 and monitored by flow meters 8 and 9. Varying the conditions is easily possible by changing the nip between the rollers of the precision pad mangle 5, but by changing the height of the floats in the flow meters 8 and 9, the needle valves 6 and 7 can be changed. It is often desirable and sometimes necessary to do so by making changes. This device has various drawbacks. Such valves often require needle valves when they have to be adjusted, and because of their configuration, small blockages can occur that affect flow rates. Also, setting is disturbed by vibration. Also, if one tank contains permanganate, the float in the flow meter is not visible and therefore useless. When increasing or decreasing the wool throughput, the needle valves 6 and 7 must be adjusted compensatingly, otherwise said fluctuations will have the effect of emptying and overflowing the transparent tank 3. The supply to the precision pad mangle 5 is controlled by adjusting the flow rate to the correct amount and measuring the absorption amount on the top sample passing through the pad.
adjusted in relation to the wool mass passing through. This device would theoretically work without care, but once the needle valve is adjusted to give the correct flow, frequent monitoring of the flow meter and adjustment of the valve will avoid slow changes. This is an essential requirement. Referring to FIG. 2 of the metering device according to the invention:
The liquid from the two tanks 1 and 2 is metered in equal volumes into a transparent tank 3 and from there through a solenoid valve 4 into a nip between the rollers of a precision pad mangle 5. The solenoid valve 4 responds to the liquid level in the processing bath of the precision pad mangle 5 and meters more or less liquid from the see-through tank 3 as required. Again tanks 1 and 2
is kept full by a pump from a ground level storage tank (not shown) and overflow is piped back to the storage tank. The overflow heights of tanks 1 and 2 should be the same. The aqueous liquid in tanks 1 and 2 is supplied by check pipes to check valves 10 and 11, which are preferably of the air-actuated double-acting piston type.
The liquid is then passed through standard plug-type valves 12 and 1.
3 and enters the mixing vessel 3. The liquid level in container 3 is monitored by a liquid level control device 14 which provides a signal to operate valves 10 and 11. Both valves receive the same signal and it is essential that they both open and close exactly at the same time to maintain the same volume of flow into the mixing vessel 3. When initially setting up the device, valve 12, which is an adjustable plug valve,
and 13 are set in the fully open position and the liquid flow from each leg of the device is measured separately. Fine tuning can be achieved by adjusting either valve 12 or 13 when the flows are not identical due to small errors in the piping design. Once this is done, these two valves require no further attention apart from occasional checks. The correct amount of hypochlorite and permanganate is in fact made up in one solution, the concentration of which can be checked by titration of its oxidizing power. The concentration of acid required in other solutions is obtained by titrating the mixed hypochlorite/permanganate directly with acid until the desired PH is obtained. After making the raw solution, a final check is performed so that the same volumes are mixed and the PH is measured. If it is correct, then processing begins.
A very convenient way of ensuring that the feeding device continues to dispense the same volume into the mixing vessels consists in simply removing a sample from the mixing vessel 3 from time to time and titrating the mixed solution to measure the pH. This method has several advantages. Once the pressure on the pad of the pad mangle is defined to give the correct liquid absorption established by actual absorption tests, the liquid supply device automatically dispenses the aqueous solution to the pad mangle without further attention. The device automatically compensates itself when increasing or decreasing wool throughput. No visual monitoring of the device is required, therefore no flow meters are provided, and problems with opaque fluids such as permanganate are eliminated. The air actuated double acting piston type valves used are wide diameter valves that are either fully open or fully closed and therefore are much less susceptible to blockage than the needle valves previously required. Examples are given below to demonstrate the practical working of the method of the invention, and also to demonstrate that the pH of the treatment solution is not greater than 7.7.
This indicates the critical importance of keeping preferably no greater than 7.5. Example 1 Ten continuous lengths of tops, each weighing 20 g/m, were passed through a 4.5 pad mangle bath filled with an aqueous solution. This aqueous solution contains 1.5% by weight of available chlorine from sodium hypochlorite, 1.5% by weight of potassium permanganate, and 1.0% of a nonionic wetting agent, which is 6 moles of ethoxylated trimethylnonanol.
% and 80% acetic acid 0.5%. The solution is PH
It had 8.4. After passing through the solution, the wool entered a precision nip that controlled the absorption of the solution to approximately 120% (by weight) of the wool. The wool speed was 6 m/min, whereby 1200 g of wool passed through the bath and nip for 1 minute each, and with it 1440 ml of the treatment solution. The bath was kept full by dispensing the liquid obtained by mixing the following solutions into it using the feeding device described above. Solution (A): Available chlorine from sodium hypochlorite
3.0% and potassium permanganate 3.0%. Temperature 20℃. Solution (B): Solution containing 1.0% of 80% acetic acid and 2.0% of the nonionic wetting agent mentioned above, temperature 20°C. Mixing was carried out immediately before introduction into the processing bath. After passing through the nip, the wool was placed on a scraper for 2 minutes and then sequentially washed with (i) a washing water bath (25°C), (ii) a sodium bisulfite solution adjusted to a pH of 5 with acetic acid.
% solution (30-35°C), (iii) a wash bath of hot running water, and (iv) a wash bath of cold running water. 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 yarns and subjected to IWS Test Method 192. In Examples 2 to 5, the treatments were carried out in the same manner as in Example 1, except that the concentration of acetic acid used in solution (B) was regulated to give the PH value of the mixed solution as shown in the table. The results of these examples and the results of control experiments are shown in the table below. 【table】

[Brief explanation of the drawing]

1 is a schematic diagram of a conventional device for metering liquid into a precision pad mangle, and FIG. 2 is a schematic diagram of the metering device of the present invention. 1 and 2 are tanks, 3 is a transparent tank, 4 is a solenoid valve, 5 is a precision pad mangle, 6 and 7 are needle valves, 8 and 9 are flow meters, 10
11 is a confirmation valve, 12 and 13 are valves, and 14 is a liquid level control device.

Claims (1)

Claims: 1. (a) from hypochlorite, permanganate and wetting agent at a pH of 6 to 7.7 by mixing aqueous liquid feeds from at least two feed vessels in a mixing vessel; producing an aqueous solution with a discontinuous supply of aqueous liquid from each supply vessel, automatically and simultaneously starting and stopping at a constant rate in response to the liquid level in the mixing vessel;
The contents of the mixing vessel are thus of essentially constant composition and do not remain in the vessel long enough for significant decomposition to occur, and the apparatus is automatically self-compensating for variations in demand; b) transferring the aqueous solution from the mixing vessel to the contained bath by horizontally opposed rollers of a precision pad mangle, the transfer being automatically controlled by the rollers in response to the liquid level in the contained bath; (c) wetting the continuous length of wool by continuously passing the continuous length of wool through a solution in the bath;
Immediately after that, pass it through the nip of the padded mangle,
The wool thus carries 85-160% of its weight in solution, the residence time of the solution in the bath is not more than 15 minutes, and the residence time of the wool in the bath is not more than 3 seconds. A method for imparting shrink-proofing properties to wool, the method comprising: 2. The method according to claim 1, wherein the aqueous solution has a pH of 7 to 7.6. 3 Based on the weight of the aqueous solution, 0.5
Available chlorine from ~3% hypochlorite, 0.5-3
% permanganate and 0.1-2% nonionic wetting agent. 4. Claims 1 and 2, wherein the supply of aqueous liquid from the supply container is controlled by an air-operated double-acting piston valve that operates in response to the liquid level in the mixing container.
The method described in Section 3 or Section 3.