Title:
WOOL STABILIZATION PROCESS
United States Patent 3617202


Abstract:
Wool is rendered resistant to shrinking by contact with a solution of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate or (trichloro), (monopotassium dichloro,) di-isocyanurate.



Inventors:
KOWALSKI XAVIER
Application Number:
04/723930
Publication Date:
11/02/1971
Filing Date:
04/24/1968
Assignee:
MONSANTO CO.
Primary Class:
International Classes:
D06M13/364; (IPC1-7): D06M3/02; D06M13/00
Field of Search:
8/127.6,128
View Patent Images:



Foreign References:
CA607971A
Primary Examiner:
Lesmes, George F.
Assistant Examiner:
Wolman H.
Claims:
What is claimed is

1. In a process of treating wool by contact with a solution containing available chlorine until the wool becomes resistant to shrinking, the improvement wherein said solution is selected from the group consisting of solutions of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate; (trichloro,)(monopotassium dichloro,) di-isocyanurate: and mixtures thereof.

2. The process of claim 1 wherein said solution is a solution of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate.

3. The process of claim 2 further comprising souring, rinsing and drying the wool.

4. The process of claim 2 wherein the concentration of available chlorine as C1 is from about 0.5 to about 1.35 percent by weight of said solution.

5. The process of claim 2 wherein said solution has a pH of from about 4 to about 5.

6. A continuous process of treating wool comprising sequentially contacting the wool with a solution of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate said solution being maintained at substantially constant concentration, and souring and rinsing the wool.

7. The process of claim 6 wherein the concentration of available chlorine as C1 is from about 0.5 to about 1.35 percent by weight of said solution.

8. The process of claim 5 wherein said solution has a pH of from about 4 to about 5.

9. The process of claim 6 comprising the sequential steps of passing the wool through a bath of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate solution, said solution being maintained at substantially constant concentration, maintaining contact between the wool and said solution for a sufficient period of time to render the wool resistant to shrinking and souring and rinsing the wool.

10. The process of claim 9 wherein said solution is maintained at substantially constant concentration by passing at least a portion of said solution from said bath into contact with solid [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate and recycling said portion into said bath.

11. The process of claim 9 wherein said solution is maintained at substantially saturated concentration by maintaining solid [(mono-trichloro,) tetra,(monopotassium dichloro,)] penta-isocyanurate in said bath.

Description:
BACKGROUND OF THE INVENTION

This invention is related to processes for stabilizing wool to render it more resistant to shrinking and felting. Particularly preferred embodiments of the invention relate to stabilization of wool by continuous processes.

This invention is an improvement on those processes previously known to the art wherein wool is stabilized by contact with a solution containing available chlorine for reaction with the wool. The term "available chlorine" comprises all reactive species thereof including, for example, C1-; OC1-; and HOCL Solutions hitherto utilized for this purpose have included for example, aqueous solutions of sodium hypochlorite, solutions or dispersions of trichlorocyanuric acid and solutions of the sodium or potassium salts of dichlorocyanuric acid. Solutions of this type upon standing often exhibit significant reductions in chlorinating action. Such instability renders it difficult to reproducibly chlorinate successive batches of woolen material in batch operation and generally precludes the practice of continuous processes.

SUMMARY OF THE INVENTION

It is an object of this invention to provide improved processes for treatment of wool to render it resistant to shrinking and felting. Particularly, it is an object of the invention to provide processes for shrinkage control of wool which permit uniform and reproducible treatment of wool; rapid treatment of wool; more convenient treatment of wool; and continuous treatment of wool.

These and other objects are obtained by treating wool with aqueous solutions of (trichloro,)(monopotassium dichloro,) di-isocyanurate or [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta-isocyanurate, preferably at the natural pH obtained by dissolving these compounds in water to provide solutions containing about 0.5-1.35 percent available chlorine calculated as Cl and at ambient temperatures. Preferably, the treated wool is subsequently given an antichlorine or souring treatment, washed and dried. The processes are applicable to a variety of wool materials including woven or knit fabrics, raw stocks, tops, yarn, and the like, The term wool is used herein to include materials composed only partly of wool fibers as well as all wool materials. Blended fiber materials will contain at least 25 percent wool fibers and the balance of fibers in the blend will be of a type not adversely affected by the chlorination reaction, for example, cellulose fibers such as cotton, regenerated cellulose, saponified cellulose acetate; polyester fibers; acrylic fibers; and the like.

The invention will be better understood from the following description of preferred embodiments.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the practice of this invention wool is stabilized by contact with an aqueous solution of [(mono-trichloro,) tetra-(monopotassium dichloro,)] penta isocyanurate, hereinafter referred to for convenience as Compound I. This compound has the general formula: ##SPC1##

Methods of preparing this compound and information regarding its properties are disclosed in U.S. Pat. No. 3,150,132, the disclosure of said patent being incorporated herein by reference.

Although the foregoing compound is preferred, the invention can also be practiced with (trichloro,)(monopotassium dichloro,)di-isocyanurate having the general formula: ##SPC2##

and hereinafter referred to as Compound II. Methods of preparing Compound II and information regarding its properties are also found in the above referred patent.

If desired, mixtures of Compound I and Compound II can be employed.

In view of advantages of Compound I, particularly in terms of availability and solubility, the invention is described by reference to embodiments employing Compound I.

In the process, Compound I is most conveniently utilized in aqueous solution at its natural pH of about 4.5. Although the limited solubility of Compound I restricts the available chlorine content of its solutions, at this pH, to about 1.35 percent (calculated as Cl) as compared to solutions of 2.5 to 3 percent of available chlorine which were generally previously utilized for wool treatment, it is found that the shrinkage control of wool is effectively accomplished at this and even lower concentrations of Compound I. If desired, higher concentrations can be obtained in more basic solutions. The effectiveness of treatment with dilute solutions is believed to be due, at least in part, to the fact that the natural pH of aqueous solutions of Compound I closely approximates the isoelectric point of wool fibers.

The process of this invention can be employed for batch or continuous treatment of wool.

In batch process treatment, according to the invention, the wool is immersed in a solution of Compound I. Contact between the wool and the solution is maintained for a length of time sufficient to provide the desired degree of chlorination. This time will, of course, be in part dependent upon the concentration and temperature of the solution. Generally, concentrations sufficient to provide 0.5-1.35 percent by weight available chlorine (calculated as C1) and temperatures of from 65° Cl) to 100° F. are utilized for convenience, rapid treatment, and economy. However, if desired, somewhat higher or lower temperatures and/or concentrations can be employed.

Excess chlorine is removed by a conventional antichlor or souring step such as treatment with a dilute aqueous solution of sodium bisulfite. The wool is then rinsed and dried.

In continuous processes, according to this invention, wool is sequentially contacted with a solution of Compound I maintained at constant concentration; treated with antichlor solution; rinsed; and dried. This can be conveniently accomplished by a series of baths fitted with squeezing roller or similar means to prevent undue transfer of solutions between baths.

The solution of Compound I is maintained at saturation or a lower equilibrium concentration by the presence of undissolved solid Compound I in contact with the solution or by cycling a portion of the solution into contact with solid Compound I. For example, when using a bath fitted with rollers to squeeze excess solution from woven material being treated, the liquid squeezed from the wool fibers can be passed through a bed of Compound I before being returned to the bath. Preferably, solid Compound I will be confined within a screen or other filter means to prevent deposition of solid Compound I on the fibers being treated.

If desired, the solutions utilized for treating the wool can contain other commonly used additives, for example, softening agents such as fatty acid compositions; mothproofing agents such as sodium silico fluoride; resinous solutions and dispersions; wetting agents; and the like.

In treating wool with Compound I according to this invention, it was surprisingly found that solutions of Compound I were capable of consistently shrink proofing successive batches of wool. Although the reason for this described performance is not fully understood, it is believed to be at least in part due to the excellent stability of solutions of Compound I. It must be noted, however, that solutions of other commercially employed shrink proofing agents which are quite stable do not exhibit the desired characteristics of the solutions utilized in the practice of this invention. For example, the stability, with respect to retention of available chlorine (expressed as %C1) solutions of Compound I and sodium dichloro isocyanurate are shown in table I below. --------------------------------------------------------------------------- TABLE I

Elapsed % available chlorine % available chlorine time found in solution of found in saturated sodium dichloroiso- solution of Compound I cyanurate __________________________________________________________________________ 0 3.15 1.35 30 min. 3.14 1.29 1 hr. 3.14 1.28 __________________________________________________________________________

The data of table I indicates that the solution of Compound I appears no more stable than the commercially utilized solution of sodium dichloroisocyanurate. Therefore, the results shown in the following example which indicate that solutions of Compound I are more consistent with respect to action on wool are completely unexpected.

It will be understood that the examples are for the purpose of further illustrating the invention and are no intended to limit the scope thereof. In the examples the term "available chlorine" refers to chlorine determined as Cl.

EXAMPLE I

A wool-treating solution is prepared by dissolving 20 grams of Compound I in a liter of water. The solution has a pH of about 4.5 and an available chlorine concentration of about 1.35 percent. A sample of wool fabric, measuring 18 by 18 inches is contacted with the solution for about 180 seconds. The sample is removed, treated with a dilute solution of sodium bisulfite, rinsed and dried. The solution is allowed to stand for 20 minutes after which a similar sample is treated in the same manner. The samples are measured, washed, and remeasured to determine shrinkage as the percentage reduction in the original area of the samples. Both samples exhibit 0 percent shrinkage. For purposes of comparison, the above experiment is repeated with similar samples using a treating solution containing 50 grams per liter of sodium dichloroisocyanuarate a material conventionally employed for the shrink proofing of wool. The first sample treated with this solution exhibits 0 percent shrinkage. However, the second exhibits 2.5 percent shrinkage indicating less complete chlorination.

This experiment demonstrates that Compound I in solution maintains stable chlorination action on wool even after prolonged periods of standing and further that the treatment is effectively accomplished at relatively low concentrations of available chlorine.

EXAMPLE II

Solutions of Compound I and of sodium dichloroisocyanurate each containing about 10 grams per liter to provide available chlorine concentrations of about 0.66 percent by weight are prepared. The solution of Compound I is adjusted by addition of sodium hydroxide solution, to a pH of 6.3, the same as the natural pH of the solution of sodium dichloroisocyanurate. Samples of wool fabric are treated with each solution, soured, and rinsed. The sample treated with Compound I exhibits 0 percent shrinkage whereas the sample treated with sodium dichloroisocyanurate exhibits 2 percent shrinkage. This clearly demonstrates the unusual effectiveness of Compound I at at very low concentrations. Further, it is seen that although it is preferred to use Compound I at its natural pH for reasons of convenience and rapid chlorination (see Example III), the compound may, if desired, be employed in solutions of various pH.

EXAMPLE III

A sample of wool fabric is treated with a solution of Compound I containing about 0.66 percent by weight available chlorine at its natural pH of 4.5 for a period of about 45 seconds. The wool is then soured with a dilute solution of sodium bisulfite, rinsed, and dried. The sample exhibits 0 percent shrinkage after washing.

EXAMPLE IV

A wool fabric is continuously fed through a bath containing a saturated solution of Compound I. The solution is maintained at saturated concentration by the presence of solid Compound I enclosed within a bag of filter cloth in the bath. The fabric is then passed through rollers to remove excess treating solution and fed into a dilute bath of sodium bisulfite. The fabric is then rinsed and dried. After washing, the fabric exhibits 0 percent shrinkage and has uniform appearance and texture, indicative of uniform chlorination.

Although this invention has been described by reference to specific embodiments, other variations of the invention within the scope of the following claims will be apparent to those skilled in the art.