US2495810A

US2495810A - Dyeing organic acid ester of cellulose textile materials with an aqueous solution of a normally acid-fading dyestuff, lower aliphatic alcohol, thiocyanate, and alkali metal hydroxide

Info

Publication number: US2495810A
Application number: US702363A
Authority: US
Inventors: Walter H Hindle
Original assignee: Celanese Corp
Current assignee: Celanese Corp
Priority date: 1946-10-10
Filing date: 1946-10-10
Publication date: 1950-01-31
Anticipated expiration: 1967-01-31

Description

Patented Jan. 31 1950 i DYEING ORGANIC ACID ESTER OF CELLU- LOSE TEXTILE MATERIALS 'WITH AN AQUEOUS SOLUTION OF A NORMALLY ACID-FADING I DYESTUFF, LOWER ALI- PHATIC ALCOHOL, THIOCYANATE, AND ALKALI METAL HYDROXIDE Walter H. Hindle, Allentown, Pa., assignor to Celanese Corporation of America, a corporation of Delaware No Drawing. Application October 10, 1946, Serial No. 702,363

8 Claims. (01. 859) This invention relates to the dyeing of textile materials and relates more particularly to the dyeing of textilev materials made of or containing yarns having a basis of cellulose acetate or other organic acid ester of cellulose textile material.

.. a An object of this invention is the provision of an improved process for the dyeing of cellulose acetate or other organic acid ester of cellulose textile materials.

Another object of this invention is to provide an improved process for the dyeing of cellulose acetate or other organic acid ester of cellulose textile materials whereby dyed materials of improved resistance to acid fading may be obtained.

Other objects of this invention will appear from the following detailed description.

In dyeing cellulose acetate or other organic acid ester of cellulose textile materials, excellent results may be obtained by employing. a solvent dyebath comprising an aqueous alcoholic solution 01 the desired dyestuff and applying said dyebath 'by mechanical impregnation methods. The dyebeen observed to exhibit a noticeable tendency to fade when exposed to an acid atmosphere. {ittempts have been made to minimize this tendi'ency toward acid fading by subjecting the organic acid ester of cellulose textile materials to certain after-treatments following dyeing. Such after-treatments involve an additional manipulative step and, since they increase the cost of the finished material, are uneconomical.

I I have now found that greatly improved resistance to acid-fading may be imparted to cellulose acetate or other organic acid ester of cellulose materials dyed by solvent dyeing methods if from 1 to 4 grams per liter of an alkali metal hy- "droxide such as sodium hydroxide or potassium hydroxide, for example, is incorporated in the alcoholic solvent dyebath employed and the resulting dyebath then applied to said cellulose acetate materials in any convenient manner. Any suitable dyeing method may be employed but padding or other form of mechanical impregnation yields the most advantageous results. Furthermore, I have found that the addition of said alkali metal hydroxide to the solvent dyebath not only improves the resistance of dyed cellulose acetate materials to acid fading but yields deeper and heavier dyeings than are obtained by employing dyebaths containing the same concentration of dyestuff but which do not contain added alkali metal hydroxide. i

The concentration of alkali metal hydroxide in the solvent dyebath is critical since I have found that the addition of less than 1 gram per liter of alkali metal hydroxide to said dyebath does not produce any increase in the depth of dyeing nor any appreciable increase in the resistance of the dyed cellulose acetate material to acid fading. Furthermora'the use of a concentration of more than 4 grams per liter does not yield the desired improvement and produces excessive saponification. The optimum concentration within the aforementioned critical limits depends, however, on the particular dyestufi employed. For certain dyestufis, the optimum concentration of alkali metal hydroxide is from 2 to 3 grams per liter while for others, a concentration of from 3 to 4 grams per liter is most advantageous.

The lower aliphatic alcohols which are suitable for use in forming the solvent dyebaths are those alcohols which are solvents for the dyestuffs employed and which exert at least a swelling or softening action on the organic acid ester of cellulose materials. While we prefer to employ ethyl alcohol in forming the dyebath, other alcohols such as methyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol, tertiary butyl alcohol, n-amyl alcohol, secondary amyl alcohol and tertiary amyl alcohol, or mixture of these alcohols may be used. The amount of the alcohol used in the dye liquor will vary depending upon the alcohol or alcohols used. Optimum results are obtained when the lower aliphatic alcohol comprises at least I by weight of the dyebath.

As examples of inorganic swelling agents for the organic acid ester of cellulose materials, there staple fiber yarns, or other may be mentioned the salts of thiocyanic acid such as ammonium thiocyanate, sodium thiocyanate, as well as other salts such as zinc thiocyanate. Optimum results are achieved employing sodium thiocyanate. The inorganic swelling agent may be present in amounts of from 1 to 3% on the weight of the dyebath. Preferably, we employ from 1.5 to 2.5% by weight.

Various dyestuffs for organic acid ester of cellulose materials may be employed in accordance with my novel process. These dyestuifs may be acid dyes which are ordinarily used for the dyeing of wool and which dov not possess any substantial affinity for organic acid ester of cel-' lulose materials when applied by the methods usually employed for applying said acid dyestufis, as well as those dyes which are relatively insoluble in water and which are usually applied I to organic acid ester of cellulose materials in the form of aqueous dispersions. Mixtures of these dyestuffs may also be employed. When these dyestuffs are applied to organic acid ester of cellulose textile materials by mechanical impregnation methods in alcoholic solutions containing an inorganic swelling agent, and an alkali metal hydroxide, in accordance with my process, the resulting dyeings are not only faster to acid fading but are of increased depth and brilliance and may be obtained, as stated, with a relatively short immersion time. The washdown of the shade in subsequent washin and finishing operations is considerably less in the case of fabrics dyed by our novel process than in the case of fabrics dyed by prior processes.

The amount of dyestuff dissolved in the dyebath will, of course, vary with the final shade desired in the material which is being dyed and may be from as low as 0.01% up to 5.0% based on the weight of the material to be dyed.

As stated, the dyebath may be applied to the organic acid ester of cellulose textile materials by padding, spraying or by other convenient method of mechanical impregnation. Thus, as a continuous process, a fabric may be unwound from a roll, passed through a solution of-the dyestufi, then between nipping rolls of a .pad ding mangle which are adjusted to permit the desired amount of dye liquor to be retained in the fabric, and the fabric then subjected directly to washing or scouring. immersion of the fabric in the dye liquor isrelatively short and may be from 1 to 6 seconds. If

desired, the fabric may be processed through the padding mangle at speeds ranging up to 60 yards per minute. a

My process is applicable not only to the dyeing of fabrics but particularly valuable results are obtained when other organic acid ester of cellulose textile materials such as staple fibers, in the form of a top, roving, or tow are dyed in accordance with my invention. Not only may faster and more uniform dyeings be obtained but, as in the case of fabrics, increased production may be achieved along with a substantial reduction in the amount of dyestuff necessary to obtain a desired shade. 1

The organic acid ester of cellulose fabrics, textile materials dyed in accordance with my process may have a basis of cellulose acetate, cellulose propionate, cellulose butyrate, or of mixed esters such as cellulose acetate-propionate and cellulose acetatebutyrate. The materials may be mixed materials containing organic acid esters of cellulose and yarns or fibers of other materials such as The duration of the A dyebath is prepared by dissolving 2000 grams of sodium thiocyanate, 300 grams of sodium hyand 25 liters of water.

droxide and 500 parts by weight of Celliton Blue AF (a mixture of 1-amino-4-anilido-anthraquinone and 1-methylamino-4-anilido-anthraquinone) in a mixture of '75 liters of ethyl alcohol A cellulose acetate fabric of a satin weave is mechanically impregnated with this dyebath employing a suitable padding mangle and the dyed fabric then washed and dried. The dyed fabric exhibits excellent fastness to acid fading on exposure for 40 hours to acid fumes in the usual standard testing cabinet. Fabric dyed with the same dyebath but without sodium hydroxide being present fades to a hello under the same conditions, and, in addition, is not dyed to as deep a shade as with the dyebath above wherein sodium hydroxide is added. Furthermore, when the concentration of sodium hydroxide in the dyebath is increased to 5 grams per liter, fabric dyed with said dyebath shows a considerable degree of fading. It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departin from the spirit of my invention. Having described my invention, what I desire to secure by Letters Patent is:

1.'Process for the coloration of organic acid ester of cellulose textile materials, which comprises mechanically impregnating said organic .acid ester of cellulose textile material with a solution of a dyestuff for the organic acid ester of cellulose material, said dyestufif being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the organic acid ester of cellulose material and from 1 to 4 grams per liter of an alkali metal hydroxide.

2. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile mate rial with a solution of a dyestuif for the cellulose acetate material, said dyestuff being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the cellulose 1 to 4 grams per liter of an alkali metal hydroxide.

3. Process for the coloration of organic acid ester of cellulose textile materials, which comprises mechanically impregnating said organic acid ester of cellulose textile material with a solution of a dyestufi for the organic acid ester of cellulose material, said dyestuff being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least by weight of a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the organic acid ester of cellulose material and from 1 to 4 grams per liter of an alkali metal hydroxide.

4. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile material with a solution of a dyestuif for the cellulose acetate material, said dyestuff being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least 60% by weight of a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the cellulose acetate material and from 1 to 4 grams per liter of an alkali metal hydroxide.

5. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile material with a solution of a dyestufl" for the cellulose acetate material, said dyestuif being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least 60% by weight of a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the cellulose acetate material and from 1 to 4 grams per liter of potassium hydroxide.

6. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile matei rial with a solution of a dyestuff for the cellulose acetate material, said dyestuif being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least 60% by weight of a lower aliphatic alcohol, a salt of thiocyanic acid which is a swelling agent for the cellulose acetate material, and from 1 to 4 grams per liter of sodium hydroxide.

7. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile material with a solution of a dyestufi for the cellulose acetate material, said dyestuif being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least 60% by weight of ethyl alcohol, a salt of thiocyanic acid which is a swelling agent for the cellulose acetate material, and from 1 to 4 grams per liter of sodium hydroxide.

8. Process for the coloration of cellulose acetate textile materials, which comprises mechanically impregnating said cellulose acetate textile material With a solution of a dyestuif for the cellulose acetate material, said dyestufi being normally subject to acid fading upon exposure to an acid atmosphere in an aqueous medium comprising at least 60% by weight of ethyl alcohol, from 1 to 3% by weight on the bath of sodium thiocyanate, and from 1 to 4 grams per liter of sodium hydroxide.

WALTER H. HINDLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,914,945 Ellis June 20, 1933 1,955,796 Ellis Apr. 24, 1934 2,017,119 Ellis Oct. 15, 1935 2,428,835 Croft Oct. 14, 1947 FOREIGN PATENTS Number Country Date 295,579 Great Britain Oct. 17, 1929 579,718 Great Britain Aug. 13, 1946

Claims

1. PROCESS FOR THE COLORATION OF ORGANIC ACID ESTER OF CELLULOSE TEXTILE MATERIALS, WHICH COMPRISES MECHANICALLY IMPREGNATING SAID ORGANIC ACID ESTER OF CELLULOSE TEXTILE MATERIAL WITH A SOLUTION OF A DYESTUFF FOR THE ORGANIC ACID ESTER OF CELLULOSE MATERIAL, SAID DYESTUFF BEING NORMALLY SUBJECT TO ACID FACING UPON EXPOSURE TO AN ACID ATMOSPHERE IN AN AQUEOUS MEDIUM COMPRISING A LOWER ALIPHATIC ALCOHOL, A SALT OF THIOCYANIC ACID WHICH IS A SWELLING AGENT FOR THE ORGANIC ACID ESTER OF CELLULOSE MATERIAL AND FROM 1 TO 4 GRAMS PER LITER OF AN ALKALI METAL HYDROXIDE.