US2565832A - Process for treating cellulose fibers and composition therefor - Google Patents

Description

Patented Aug. 28, 1951 PROCESS FOR TREATING CELLULOSE FIBERS AND COMPOSITION THERE- FOR Thomas C. Whitner, Elizabeth, N. J.

No Drawing. Application July 18, 1947, Serial No. 761,987

I -Clainris.

This invention relates to the treating of cellulose fibers and particularly to impregnating such fibers with sericeous material.

In U. S. Patent 2,417,388 I have disclosed a method for impregnating cellulose fibers with .sericeous material and which involves dissolving silk fibers in an aqueous solution of an al- .kylolamine-copper complex and an alkali metal hydroxide; then saturating cellulose fibers with this solution; and afterwards washing the saturated fibers with an aqueous solution of an acidic agent which forms water-soluble salts with the copper complex and the alkali metal hydroxide. .Ihave described another method (in my copending application, Ser. No. 748,674) for impregnating cellulose fibers which comprises dissolving .silk fibers in an aqueous soution containing a tetra-alky'lol ammonium hydroxide and a copper complex thereof, saturating the cellulose fibers with this solution, and'afterwards washing the fibers with an aqueous solution of an acidic agent. The latter, of course, should form water-soluble salts with the copper complex, as wiell as with the tetra-alkylol ammonium hydrox- 1 e.

My experiments involving impregnation of cellulose fibers with sericeous material have indicated that silk fibers are insoluble, or substantially so, in an aqueous solution of an alkylolamine-copper complex as well as in an aqueous solution of a tetra-alkylol ammonium hydroxide. However, when these two substances (the copper complex and the tetra-alkylol ammonium hydroxide) are present simultaneously in an aqueous solution, then the latter becomes a solvent for silk fibers. Moreover, the solvent effect for such fibers is enhanced or increased if a small proportion of an alkali metal hydroxide, such as sodium or potassium hydroxide, is also present in solution with the alkylolamine-copper complex and the tetra-alkylol ammonium hydroxide.

The aqueous solutions suitable for my purpose may be prepared in any convenient manner. For example, a water-soluble copper salt (such as copper chloride, sulfate or acetate) is dissolved in water, and to this solution is added slowly an .alkylolamine until the precipitate of copper hydroxide (which is .formed at first) redissolves thus giving rise to a clear blue aqueous solution of the alkylolamine-copper complex. In this solution then is dissolved a tetra-alkylol ammonium hydroxide and, if desired, a small proportion of an alkali metal hydroxide. The resulting aqueous liquid afterwards is employed asa solvent for silk fibers. Another method involves precipitating copper hydroxide from an aqueous ,solution of a copper salt with the aid of an alkali metal hydroxide, filtering the precipitate and washing it with water until substantially free of all alkali and salts, dissolving the washed copper hydroxide in an aqueous solution of an alkylolamine, and then dissolving a tetra-alkylol ammonium hydroxide and silk fibers (in the order named) in the aqueous solution of copper compleX.

After the aqueous solution of silk is prepared, the cellulose fibers can be impregnated therewith in any convenient manner. To illustrate, cellulose fibers may be immersed in the solution of silk and worked therein until they are completely saturated. Or, the solution of silk may be dropped or sprayed onto the fibers until the latter are saturated. Any other appropriate method can be employed, provided the cellulose fibers are thoroughly and completely impregnated thereby.

The next operation consists in washing the impregnated cellulose fibers with an aqueous solution of an acidic agent, e. g., hydrochloric or sulfuric acid or sodium or potassium acid sulfate, whereby the copper complex is transformed into water-soluble salts (copper and alkylolamine salts) and the tetra-alkylol ammonium hydroxide also is changed into a water-soluble salt. If an alkali metal hydroxide was present in solution, the acidic agent should furnish a water-soluble salt on interaction with it. After washing with the aqueous solution of acidic agent, the cellulose fibers are rinsed thoroughly with water to remove substantially all acidic agent and watersoluble salts which may have been retained by them. The fibers then are dried.

The following examples will illustrate my invention.

Example 1.Crystalline copper sulfate (CuSO4-5H2O) was dissolved in water and to the aqueous solution was added triethanolamine slowly until the precipitate of copper hydroxide (first formed) dissolved and a deep blue colored solution was obtained. The latter was diluted with water until its concentration was equivalent to 2 g. of copper salt per cc. of solution. Next, the solution was admixed with one-half its volume of an equeous solution of 40 per cent tetraethanol ammonium hydroxide. In the resulting liquid was dissolved silk until its concentrating was 1.3 per cent.

A sample of bleached cotton cloth was immersed in some of the silk solution for 1 hour at 3 room temperature. The sample then was removed, Washed with dilute aqueous sulfuric acid and afterwards with water. The fabric was dried by exposure to the atmosphere. This treated cloth had a much smoother and even silky feel as compared with the untreated material.

This treated sample and also one of the original bleached cloth were dyed separately in the following manner: Each fabric was placed in a bath consisting of 100 parts of water (per 1 part of cloth) and in which was dissolved an amount of a red substantive dye equal to 12 per cent of the weight of the fabric. After the samples had become saturated with the dye solution, the temperature of each bath was increased to 60 C. over a period of minutes, maintained at 60 to 65 C. for 30 minutes, and then each bath was allowed to cool to room temperature. The fabrics were removed from the baths, rinsed well with cold water, and air dried.

Both samples of dyed material were red in color, but the treated cotton goods was a darker shade of red thanthe untreated fabric.

Example 2.-Copper hydroxide was prepared by dissolving cupric chloride and approximately one-third of its weight of ammonium chloride in water, adding sufiicient aqueous sodium hydroxide to effect substantially complete precipitation of dissolved copper as the hydroxide, filtering the precipitate and washing it with water until substantially free of all alkali and salts, and then drying the precipitate by exposure to the atmosphere.

The dried material was admixed with water, and ethanolamine was added slowly to the mixture until all of the water-insoluble copper compound dissolved and a clear blue solution was obtained. The latter was diluted with water until the concentration of copper therein was equivalent to 6.4 g. of copperoxide (CuO) per 100 cc. of solution. The latter then was admixed with one-third its volume of per cent tetraeethanol ammonium hydroxide. Small portions of silk cloth were added to this solution of copper complex slowly and with stirring until silk no. longer appeared to dissolve therein.

Bleached cotton yarn was immersed in some of the silk solution for 1 hour at room temperature. The yarn then was removed, washed successively with aqueous sulfuric acid and with water, and afterwards was air dried. This treated sample had a smooth silky feel as compared with the untreated bleached yarn.

Example 3.Crystalline copper sulfate (CuS04.5H2O) was dissolved in water, triethanolamine added until a clear blue solution was obtained, and the latter then was diluted with water until its concentration was equivalent to 13.3 g. of the copper salt per 100 cc. To this liquid was added one-third its volume of 40 per cent tetraethanol ammonium hydroxide. In the resulting solution was dissolvedsuflicient potassium hydroxide to react with the salt (formed by inter.- action of the alkylolamine and copper salt) and to give substantially 1 per cent of the free or uncombined alkali metal hydroxide. During dissolution of the latter, some crystalline salt (apparently potassium sulfate) precipitated. This material was. separated by filtration and the filtrate was saturated with dissolved silk fibers.

Unbleached cotton cloth was immersed for 2 hours at room temperature in some of the silk solution. Afterwards, the cloth was removed from the liquid and washed suocessivelywith dilute aqueous sulfuric acid and with Wate and 4 then air dried. This treated cloth had a very smooth feel as compared with the untreated fabric.

A portion of the treated cotton goods and also one of the untreated material were dyed in the following manner: Each sample was placed in a dye bath consisting of parts of water per 1 part of cloth and containing 5 per cent (on weight of cloth) of a red acid dye dissolved therein. Each sample was kept immersed in the respective bath for 3 hours at room temperature. Afterwards, the fabrics Were removed from the baths, rinsed well with cold water, and air dried.

Both samples were a light red in color, but the silk-impregnated cotton was a darker shade of red than the other untreated cotton.

Example 4.Copper hydroxide was prepared as indicated in Example 2. The dry hydroxide was admixed with approximately 6 times its weight of water and diethanolamine was added slowly to the mixture until a clear blue solution was obtained. To this liquid was added one-half of its volume of 40 per cent aqueous tetra-ethanol ammonium hydroxide and in the resulting solution was dissolved substantially 3 per cent of sodium hydroxide. On standing for several hours a small quantity of precipitate settled. This was removed by filtration and the clear solution on analysis gave a copper content equivalent 'to.5.6 g. of copper oxide (CuO) per 100 cc. This clear liquid was saturated with dissolved silk fibers.

Unbleached cotton yarn was covered with some of this silk solution and worked therein for 1 hour at room temperature. Afterwards, the yarn was washed successively with aqueous sulfuric acid and. water, and then dried; This treated yarn had a very silkyfeel and a distinct scroop as compared with the untreated yarn.

It will be seen that my invention involves preparing an aqueous solution containing an al kylolamine-copper complex and a tetra-alkylol. ammonium hydroxide and dissolving silk fibers" therein. The solubility of silk in such an aqueous solution can be increased by the prior dissolution of a small proportion, say 0.5 to 4 per cent, of an alkali metal hydroxide, such as sodium or potassium hydroxide. My invention also includes impregnating cellulose fibers with the aqueous solution of silk (prepared as just indicated) and afterwards washing the fibers with an aqueous solution of an acidic agent forming water-soluble salts and with the copper complex and tetraalklyol ammonium hydroxide and also with alkali metal hydroxides, if the last-named substance be presented in the silk solution. This step of washing with the aqueous solution of' acidic agent effects precipitation of sericeous material in and/or on the cellulose .fibers. Also, a considerable proportion of the water-soluble salts formed during the washing step are eliminated from the cellulose fibers. Next, the cellulose fibers are washed'well'with water to effect substantially complete removal from them of all acidic agent and all water-soluble salts.

Aklylolamines which are suitable for my purpose may be either monalkylolamines,' such as ethanolamine or 2-amino-2-methyl-propanol, or polyalkylolamines, such as diethanolamine, triethanolamine or 2-amino-Z-methylpropanediol- 1,3. It will be noted that these compounds also are either monohydroxy or polyhydroxy substances. Tetra-alkylol ammonium hydroxides which are applicable inpreparing the aqueous solutions of silk can be exemplified by tetraethanol, tetra-propanol and itetra -butanol ammonium hydroxide.

In making the aqueous solutions intended as solvents for silk, I find it convenient first to prepare the alkylolamine-copper complex dissolved .in the aqueous medium. As previously mentioned, this preparation may be effected. by .dissolving a copper salt in 'water and then .adding an alkylolamine slowly to the solution until the precipitate which is formed at first eventually dissolves. Or, copper hydroxide may be precipitated from the solution of copper salt with the aid of an alkali metal hydroxide (or other suitable alkali hydroxide), washed with water until free of any substantial proportions of alkali and salts, and then dissolved in an aqueous solution of the aklylolamine. A slight excess of the alklyolomine over that required for changing the copper into the copper complex apparently is not harmful. To the solution of alklyolamine-copper complex then is added the tetraalkylol ammonium hydroxide in whatever proportion may .be necessary or desirable. Afterwards, the alkali metal hydroxide (either as a solid or in aqueous solution) is incorporated in the solution of alklyolamine-copper complex and substituted ammonium hydroxide. Of course, between any one of the above-mentioned steps or following the last one, dilution with water to give a solution of desired concentration of ingredients is permissible.

The quantity of silk which can be dissolved in the solution of copper complex will depend upon the proportion of the complex, of the tetraalkylol ammonium hydroxide and of the alkali metal hydroxide. By varying these three factors it is possible to obtain solutions whose concentrations of silk will vary over a considerable range. Silk fibers, before dissolution in the copper solution, preferably are subjected to a degumming operation or treatment. If desired, they may be bleached also.

Cellulose fibers which are suitable for my purpose include cotton, linen and the like. Before being impregnated with the silk solution, such fibers should be substantially free of extraneous materials such as sizing and the like. Cellulose fibers which are unbleached, bleached, bleached and mercerized, or unbleached and mercerized can be treated according to this invention. The so-called regenerated cellulose fibers are also applicable. Furthermore, the fibers may be in the form of loose fibers, yarn or cloth.

What I claim is:

1. The process for treating cellulose fibers which comprises impregnating saidfibers with an aqueous solution of essentially an alkylolaminecopper complex and an amount of a tetra-alkylol ammonium hydroxide to form with said complex a solvent for silk fibers and in which solution is dissolved silk, washing said impregnated fibers with an aqueous solution of an acidic agent yielding water-soluble salts with said copper complex and with said tetra-alkylol ammonium hydroxide, and removing substantially all of said watersoluble salts from said cellulose fibers.

2. The process for treating cellulose fibers which comprises impregnating said fibers with an aqueous solution of essentially an alkylolaminecopper complex and an amount of tetra-ethanol I ammonium hydroxide to form with said complex a solvent for silk fibers and in which solution is dissolved silk, washing said impregnated fibers with an aqueous solution of an acidic agent yielding water-soluble salts with said copper complex and with tetra-ethanol ammonium hydroxide, and removing substantially all of said watersoluble salts from said cellulose fibers.

. .-complex a solvent for silk fibers and in which solution is dissolved silk, washing said impregnated fibers with an aqueous solution of an acidic agent yielding water-soluble salts with said copper complex and with tetra-ethanol ammonium hydroxide, and removing substantially all of said watersoluble salts from said cellulose fibers.

4. The process for treating cellulose fibers according to claim 3 in which the monoalkylolamine-copper complex is ethanolamine-copper complex.

5. The process for treating cellulose fibers which comprises impregnating said fibers with an aqueous solution of essentially a polyalkylolamine-copper complex and an amount of tetraethanol ammonium hydroxide to form with said complex a solvent for silk fibers and in which solution is dissolved silk, washing said impregnated fibers with an aqueous solution of an acidic agent yielding water-soluble salts with said copper complex and with tetra-ethanol ammonium hydroxide, and removing substantially all of said water-soluble salts from said cellulose fibers.

6. The process for treating cellulose fibers according to claim 5 in which the polyalkylolaminecopper complex is diethanolamine-copper complex.

7. The process for treating cellulose fibers according to claim 5 in which the polyalkylolaminecopper complex is triethanolamine-copper comlex.

8. A bath for impregnating cellulose fibers which comprises an aqueous solution of essentially an alkylolamine-copper complex and an amount of a tetra-alkylol ammonium hydroxide to form with said complex a solvent for silk fibers, and silk dissolved therein.

9. A bath for impregnating cellulose fibers which comprises an aqueous solution of essentially an alkylolamine-copper complex and an amount of tetra-ethanol ammonium hydroxide to form with said complex a solvent for silk fibers, and silk dissolved therein.

10. A bath for impregnating cellulose fibers which comprises an aqueous solution of essentially a monoalkylolamine-copper complex and an amount of tetra-ethanol ammonium hydroxide to form with said complex a solvent for silk fibers, and silk dissolved therein.

11. A bath for impregnating cellulose fibers which comprises an aqueous solution of essentially a polyalkylolamine-copper complex and an amount of tetra-ethanol ammonium hydroxide to form with said complex a solvent for silk fibers, and silk dissolved therein.

12. The process as set forth in claim 1 in which the aqueous solution contains a concentration equivalent to 2 g. of copper salt per c. c. of solution and which aqueous solution is admixed with from A9, to its volume of an aqueous solution of 40 tetra-alkylol ammonium hydroxide.

13. The process of claim 12 in which the alkylol derivative is tetra-ethanol ammonium hydroxide.

14. A bath as set forth in claim 8 in which the aqueous solution contains a concentration equivalent to 2 g. of copper salt per 100 c. c. of solution and which aqueous solution is admixed with frbm to A; its volume of an aqueous solu- UNITED STATES PATENTS tion of 40% tetra-alkylol ammonium hydroxide. N

15. A bath as set forth in claim 14 in which the $333; ag f alkylol derivative is tetra-ethanol ammonium hydroxide. 5 OTHER REFERENCES THOMAS C. T Synthetic Organic Chemicals, Carbide & Carbon Chemicals Corp., 11th ed., June 1, 1942, page 61. REFERENCES CITED Matthews Textile Fibers, 5th ed., John Wiley & The following references are of recofd in the Sons, Inc., 1947, page 721. file of this patent: 10 v 7

Claims (1)

1. THE PROCESS FOR TREATING CELLULOSE FIBERS WHICH COMPRISES IMPREGNATING SAID FIBERS WITH AN AQUEOUS SOLUTION OF ESSENTIALLY AN ALKYLOLAMINECOPPER COMPLEX AND AN AMOUNT OF A TETRA-ALKYLOL AMMONIUM HYDROXIDE TO FORM WITH SAID COMPLEX A SOLENT FOR SILK FIBERS AND IN WHICH SOLUTION IS DISSOLVED SILK, WASHING SAID IMPREGNATED FIBERS WITH AN AQUEOUS SOLUTION OF AN ACIDIC AGENT YIELDING WATER-SOLUBLE SALTS WITH SAID COPPER COMPLEX AND WITH SAID TETRA-ALKYLOL AMMONIUM HYDROXIDE, AND REMOVING SUBSTANTIALLY ALL OF SAID WATERSOLUBLE SALTS FROM SAID CELLULOSE FIBERS.