US3667899A

US3667899A - Dyeing of polyacrylonitrile textile materials with cationic dyes in the presence of aromatic esters

Info

Publication number: US3667899A
Application number: US25578A
Authority: US
Inventors: James J Hartnett; Robert Feigin
Original assignee: Sybron Corp
Current assignee: Lanxess Sybron Chemicals Inc
Priority date: 1970-04-03
Filing date: 1970-04-03
Publication date: 1972-06-06
Anticipated expiration: 1989-06-06

Abstract

ESTERS OF THE MONOCARBOXYLIC AND/OR DICARBOXYLIC AROMATIC ACIDS AND DERIVATIVES THEREOF ARE USED AS LEVELING AGENTS IN THE DYEING OF POLYACRYLONITRILE-CONTAINING MATERIALS WITH CATIONIC DYES. LEVEL DYEING OF POLYACRYLONITRILE MOIETIES ARE ACHIEVED WITHOUT LOSS OF COLOR YIELDS OR BULKING EFFECTS.

Description

United States Patent Int. Cl. D0611 5/04 US. Cl. 8-173 25 Claims ABSTRACT OF THE DISCLOSURE Esters of the monocarboxylic and/ or dicarboxylic aromatic acids and derivatives thereof are used as leveling agents in the dyeing of polyacrylonitrile-containing materials with cationic dyes. Level dyeing of polyacrylonitrile moieties are achieved without loss of color yields or bulking effects.

BACKGROUND OF THE INVENTION This invention relates in general to a process for dyeing polyacrylonitrile materials, and more specifically, to a process for level dyeing polyacrylonitrile materials with basic or cationic dyestuffs.

Polyacrylonitrile materials may be in the form of fibers, fabrics or shaped articles. This invention applies to all forms of polyacrylonitrile materials derived from acrylonitrile polymers and copolymers containing 85% or less acrylonitrile units in the molecule and to all such materials which are modified with adjuvants which pro vide anionic dye sites as acceptors for cationic dyestuffs. It also applies to the dyeing of polyacrylonitrile which is blended with other synthetic or natural substances. For the sake of brevity the term acrylic is used to designate the polyacrylonitrile substances undergoing treatment with dyestuffs.

Acrylic fibers have such a strong affinity for basic dyestuffs that the dyes, which become absorbed on the dye sites, do not distribute themselves uniformly under atmospheric dyeing conditions at the boil. This results in uneven or unlevel dyeing. In the dyeing of acrylics, the afiinity of each dye and the rate of exhaustion of dyestuffs from the dyebath vary with the dye being used often making the levelness of dyeing unpredictable. Temperature difference from one part of the dyeing equip ment to the other aggravates this difficulty. Certain chemical additives and methods have been used to overcome these difiicultie to a certain extent, but there are still deficiencies in performance, handling and cost which make them unacceptable for routine dyeing.

One method used to prevent uneven or unlevel dyeing of acrylic fibers is known as the anionic retarder system. In the anionic retarder system of dyeing with cationic dyestuffs, an anionic precipitant or complexing agent such as the sodium salt of sulfonated dinaphthyl methane is employed. This additive forms a complex which is dispersed in the dyebath together with a non-ionic surfactant to keep the bath in a suitable state of colloidal dispersion. At temperatures below boiling the complex bonds very loosely with the acrylic fiber and some migration or leveling of the dye occurs on the surface of the fiber. As the temperature of the dyebath is raised, this complex breaks down and allows the dyestuff to diffuse into the fiber. The anionic retarder remains active in the dyebath. While this method is useful in promoting leveling, it causes a very great reduction in color yield and loss of dyestuff which is retained in the dyebath. The dyes do not penetrate the material well and in some instances the incompatabiliice ties of cationic dye and anionic agent are too great to be economically overcome by means of a non-ionic additive.

Another method used to prevent unlevel or uneven dyeing is known as the cationic retarder system of dyeing. In this system a cationic agent is employed at the start of the dyeing. Cationic retarders are generally water-soluble organic substances which decrease the rate of exhaustion of the cationic dyestuffs. In effect they act as competitive colorless dyestuffs which block dye sites and generally lack migrating ability themselves. Even with these cationic retarders the dyestuffs strike or exhaust at different rates so that fast striking dyes exhaust rapidly at the higher temperatures and slow striking dyes do so slowly. Cationic retarders cause a reduction in color yield although not as great as the anionic retarders and are difiicult to remove from the material undergoing treat ment with dyestuffs. When acrylics of a light or pastel shade are desired, it is necessary to use high concentrations of cationic retarder. Since cationic retarders are difficult to remove from the acrylics, it is necessary to use large amounts of dyestuff to subsequently overdye the light or pastel acrylics, for example, to change an acrylic fabric from a light blue shade to a navy blue. Accordingly, in overdyeing the pastel colored acrylics, it is necessary to use a higher concentration of the dyestuff than when the pastel-colored acrylic has been dyed in the absence of the retarder.

In certain types of dyeing of acrylic fibers and yarns e.g., those used in sweaters and carpeting, it is desirable to obtain a high bulk effect. Bulking is achieved by allowing the fiber to shrink in the boiling dye-bath. Cationic retarders greatly reduce bulking.

Non-surface active cationic leveling agents such as benzyltrimethylammonium chloride and benzylpyridiurn chloride, are often used in place of cationic retarders. These agents have greater mobility than retarders, however, they cause losses in dyestutf yields.

All of the conventional methods of dye leveling are characterized by sensitivity to overdoses of the leveling agent. Excessive amounts or even small quantities above the optimum of the cationic retarders, anionic retarders and non-surface active cationic leveling agents cited above can greatly prolong dyeing time, reduce color yields, decrease bulking and fail to improve the levelness of the dyeing for which they are intended.

OBJECTS OF THE INVENTION Accordingly, it is an object of this invention to provide a process for the level dyeing of polyacrylonitrile materials by means of basic or cationic dyestuffs.

It is another object of this invention to provide a process for the level dyeing of polyacrylonitrile materials wherein diiferent dyes used in the process produce minimum variation in dye aflinities and rate of exhaustion of dyestuffs from the dyebath.

It is still another object of this invention to provide a process for the dyeing of polyacrylonitrile materials wherein temperature differences between various parts of the dyeing equipment do not produce unlevel and uneven dyeing.

Another object of this invention is to provide an economic process for the dyeing of polyacrylonitrile materials. wherein there is excellent dye pentration and little or no reduction in color yield due to the promotion of dye leveling in the material.

Still another object of this invention is to provide a process for the level dyeing of polyacrylonitrile materials wherein the agents used to promote the leveling are easily removed from the material undergoing treatment with dyes and do not inhibit subsequent overdyeing.

Still another object of this invention is to provide a process for dyeing acrylics wherein a high bulk elfect is retained when agents promoting leveling of the dye are added to the dye bath.

Another object of this invention is to provide a process for level dyeing of acrylics wherein excessive amounts of the leveling agent will not have adverse effects on dyeing time, color reduction, bulking and levelness.

SUMMARY OF THE INVENTION We have found that these and other objects are accomplished by the addition of lower alkyl esters of monocarboxylic and dicarboxylic acid derivatives of aromatic compounds in a dyebath containing at least one cationic dye. This class of esters will hereinafter be referred to as aromatic esters. The aromatic esters of this invention may be advantageously applied with emulsifiers in order to get be reasonably uniform dispersion of the aromatic esters in the dyebath. However, level dyeing is obtained even in the absence of the emulsifier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aromatic esters which are preferred as additives to induce level dyeing of acrylic materials, are those selected from the group having the following structural formula:

(COOR), (C1): -d

where R is a lower alkyl of C to C when a is 2 and C 'to C when a is l; b is 0 or 1 and 0 when a is 2; c is 0, 1 or 2; d is O or 1 and 0 when a is 2. Examples of lower alkyl radicals are methyl, ethyl, propyl, isopropyl, and butyl. In general the aromatic moiety includes benzene, halogen substituted benzene, hydroxybenzene (phenol) and lower alkyl derivatives of benzene. Examples of these aromatic esters are the methyl ester of monochlorobenzoic acid, the methyl ester of dichlorobenzoic acid, butyl benzoate, methyl salicylate, methyl cresotinates, methyl toluates, dimethyl orthophthalate, dimethyl meta-phthalate, dimethyl paraphthalate, the isopropyl esters of ortho-, meta-, and para-phthalic acid and the like. Combinations and mixtures of the aromatic esters may also be utilized in level dyeing. Concentration of the aromatic esters is not critical. It is only necessary to have an effective amount of the aromatic ester. We have found that as little as 0.4% on the weight of the acrylic material being dyed is an effective amount. Concentrations of or higher of the aromatic ester (based on the weight of the acrylic) produce fully satisfactory performance. However, concentrations of the aromatic ester in excess of 20% are generally not required to produce the desired leveling effect. Good results are obtained when the concentration of aromatic ester is between 1% and 6% (based on the weight of the acrylic). The preferred concentration provides adequate leveling at reasonable cost.

Since the aromatic esters of this invention are at most slightly soluble in the dyebath, they are usually applied with a suspending agent or emulsifier in order to provide a uniform dispersion of the aromatic ester at the start of the dyeing. The emulsifiers useful for suspension of the aromatic esters in the dyebath are preferably the non-ionic type. However, small quantities of anionic or cationic emulsifiers may be included therein. A typical emulsifier is a mixture of ethoxylated nonylphenol, diisopropylphosphate and monoethanolamine in 33% isopropanol in Water. Emulsifiers may be used in effective amounts, that is, there may be more emulsifier added to the composition than aromatic ester, or there may be less emulsifier than aromatic ester. In fact we have found that leveling of the dye may be accomplished with no emulsifiers in the dye bath.

It is preferred that the-aromatic ester be added to the dyebath at the start of the dyeing. However, effective level dyeing is possible even if addition of the aromatic ester and emulsifier are made subsequent to the start of the dyeing.

Other chemicals are ordinarily employed in the dyeing of acrylic materials. For example, acetic acid and sodium acetate are used as buffers to mtaintain pH control of 4.5 to 5.5 which is generally the optimum pH for most cationic dyes. Sodium sulfate is used for stabilizing the shade of many dyes against pH variations. It is deemed that other chemicals and techniques may be used in the practice of this invention by one skilled in the art of dyeing.

The following examples are set forth to illustrate more clearly the principles and practice of the invention to those skilled in the art. In the examples given below all chemical concentrations are expressed as percent of acryl ic (fiber or fabric) weight.

The following aromatic ester-emulsifier compositions were prepared in accordance with this invention and are used in examples set forth below:

COMPOSITION A 55 parts dimethyl phthalate 45 parts emulsified comprising:

24 parts ethoxylated nonylphenol 4 parts diisopropylphosphate 2 parts monoethanolamine 15 parts 33% isopropanol in water COMPOSITION B 55 parts diethyl phthalate 45 parts emulsifier as in Composition A COMPOSITION C 55 parts butyl benzoate 45 parts emulsifier as in Composition A COMPOSITION D 55 parts methyl-p-toluate 45 parts emulsifier as in Composition A COMPOSITION E 55 parts methyl benzoate 45 parts emulsifier as in Composition A COMPOSITION F 55 parts methyl salicylate 45 parts emulsifier as in Composition A COMPOSITION G 55 parts methyl-o-cresotinate 45 parts emulsifier as in Composition A COMPOSITION H 77 parts dimethyl phthalate 23 parts emulsifier as in Composition A Example 1 Comparative evaluation of leveling performance was made in a Launder-O-Meter by migration experiments using equal weights of undyed acrylic fabric and fabric dyed with cationic dyestuff, 2% Basic Red 22. A liquor ratio of 10 parts to 1 part total fabric weight was used. Each bath contained (based on total fabric weight) 10% anhydrous sodium sulfate, 0.5% sodium acetate and acetic acid to adjust the bath pH to 4.5. The following additives were incorporated into separate Launder-O- Meter pots: (a) none; (b) 4% of 60% benzyltrimethylammonium chloride solution; (c) 4% of 30% lauryltrimethyl-ammonium chloride solution, a conventional cationic retarder; (d) 2.8% Composition H and (e) 2.2% dimethyl phthalate. The pots were sealed, fastened in the Launder-O-Meter and then heated to the boil. Agitation and heating were maintained for one and a half hours. After cooling, the fabrics were rinsed and evaluated for dyestuff transfer from dyed to undyed material. The fabrics treated with 2.8% of Composition H and 2.2% dimethyl phthalate showed the greatest amount of dyestuff transfer from dyed to undyed fabric and were essentially equivalent. The control (a), (b) and (0) were less effective. The experiment was repeated using fabrics dyed with 2% Basic Blue 3 Cl. 51005 and 2% Basic Green 4 CI. 42000. Similar results were obtained.

Example 2 Comparative evaluations of leveling performance were conducted with each of the following additives:

(a) 4% of a 60% solution of benzyltrimethylammonium chloride (b) 4% of Composition A (c) 4% of Composition B (d) 4% of Composition C Tests were conducted as in Example lat a liquor to fabric ratio of 25:1 instead of :1 using acrylic fabrics dyed with 1% Basic Orange 25 and 1% Basic Blue 3.

In each case, that is, those dyed with 1% Basic Orange 25 and those dyed with 1% Basic Blue 3, more dyestuflt was transferred with Compositions A, B and C than with the solution of benzyltrimethylammonium chloride.

Example 3 Comparative laboratory beaker dyeings were carried out at a liquor ratio of :1 on an acrylic yarn using a dye combination of 0.1% Du Pont Severon Blue EG and 0.05% Basic Yellow 21. With 3% Composition H against a control and incorporating acetic acid, sodium acetate and sodium sulfate in each beaker as in Example 1, dyeing with Composition H produced well penetrated dye with superior lightfastness and equal bulking of the yarn. Similar results were obtained when the dyestuff concentrations were increased five fold.

Example 4 Example 3 was repeated using a very heavy dyestutf combination of 3.5% Geigy Maxilon Red 3BL and 1.5% Maxilon Red GRL. Approximately 15% greater exhaustion of dyestuffs and yield of color were obtained with 3% Composition H as compared to the control.

Example 5 Comparative simultaneous dyeings were made in an Ahiba Vistamatic automatic dyeing machine on an acrylic fabric at a liquor to fabric ratio of :1 using a combination of 0.5% Basic Yellow 13 and 1% Basic Blue 77. Each dye bath contained 10% sodium sulfate, 0.5% sodium acetate and acetic acid to maintain pH at 4.5 plus 4% of one of the following additives:

#1 60% solution of benzyltrimethylammonium chloride #2 solution of lauryltrimethylmammonium chloride #3 Equal parts of sodium disulfonaphthylmethane and ethoxylated tallow alcohol (anionic retarder system) #4 Composition A #5 Composition B #6 Composition C #7 Comoposition D #8 Comoposition E #9 Composition F #10 Composition G #11 None (control) The temperature of the dyebaths was raised at the rate of approximately 1 F. per minute to the boil and then maintained at the boil for one and a half hours. As the temperature was raised the machine was stopped periodically to remove small swatches of the separate fabrics to observe the rate of dye exhaustion. The dye bath incorporating additive #2, typical of the cationic retarder system, showed very little dye exhaustion even up to the boil. Additive #1 showed only slight retardation. Additive #3, typical of the anionic retarder system, showed very slight retardation, but when the boil was reached there was a very great deal less exhaustion and compared to the control the final dyeing showed a loss of about 35% dyestufii, while additives #1 and #2 showed about 10% and 15% loss respectively. Additives #4-#10, illustrative of this invention caused excellent penetration of the dye and equality in color yield when compared with the control. p

In accordance with the above examples, the objects of this invention have been carried out. Acrylonitrile polymers have been subjected to dyeing with cationic dyestutfs by means of a process which caused superior lightfas'tness and uniform and level penetration of the acrylic material with dye. The process of this invention increased exhaustion of the dyestufi from the dye bath, that is, caused the acrylic material to incorporate greater amounts of dye resulting in less dyestulf retained in the used dye bath. Acrylic yarns subjected to dyeing in accordance with the process of this invention showed equal bulking throughout.

The above examples are not meant to limit the scope of the invention or the applications to which this invention may be directed. It is to be understood that although the invention has been described with specific reference to particular embodiments thereof, it is not to be so limited, since changes and alterations therein may be made which are in the full intended scope of this invention as defined by the appended claims.

We claim:

1. A process for level dyeing acrylonitrile polymer textile materials with a cationic dye comprising adding at least one aromatic ester having a structural formula:

(000R). M s)a where R is a lower alkyl radical and a is 1-2; b is 0-1 and 0 when a is 2; c is 0-2; d is 0-1 and 0 when a is 2, to an acid dye bath containing at least one cationic dye; adding the acrylonitrile polymer to said dye bath; heating said dye bath; and removing said acrylonitrile polymer from said dye bath.

2. A process in accordance with claim 1 wherein the lower alkyl radical is one to four carbon atoms when a is 2 and one to eight carbon atoms when a is 1.

3. A process in accordance with claim 1 wherein the lower alkyl radical is selected from the group consisting of methyl, ethyl, propyl, isopropyl and butyl.

4. A process in accordance with claim 1 wherein the aromatic ester is dimethyl phthalate.

5. A process in accordance with claim 1 wherein the aromatic ester is diethyl phthalate.

6. A process in accordance with claim 1 wherein the aromatic ester is butyl benzoate.

7. A process in accordance with claim 1 wherein the aromatic ester is methyl-p-toluate.

8. A process in accordance with claim 1 wherein the aromatic ester is methyl benzoate.

9. A process in accordance with claim 1 wherein the aromatic ester is methyl salicylate.

10. A process in accordance with claim 1 wherein the aromatic ester is methyl-o-cresotinate.

'11. A process in accordance with claim 1 wherein the concentration of the aromatic ester is at least 0.4% based on the weight of the material to be dyed.

12. A process in accordance with claim 1 wherein the concentration of the aromatic ester is from 1% to 6% based on the weight of the material to be dyed and the pH of the dye bath is about 4.5 to 5.5.

13. The process of claim 1 wherein the acrylonitrile polymer is a fiber.

14. The process of claim 1 wherein the acrylonitrile polymer is a fabric.

15. The process of claim 1 further comprising adding a non-ionic emulsifier to the dye bath to suspend the dye bath insoluble aromatic ester.

'16. The process of claim 15 wherein the non-ionic emulsifier comprises minor quantities of anionic emulsifier.

17. The process of claim '15 wherein the non-ionic emulsifier comprises minor quantities of cationic emulsifier.

18. A dye bath composition for dyeing acrylonitrile polymer textile materials with cationic dye consisting of:

(a) a fluid medium;

(b) at least one cationic dye;

(c) at least one aromatic ester having a structural formula:

(000R). HM D i -sh where R is a lower alkyl radical and a'is 1-2; b is 0-1 and 0 when a is 2; c is 0-2; d is 0-1 and 0 when a is 2; and

(d) an acid to adjust the pH of said fluid medium. 19'. The composition of claim 18 wherein the lower alkyl radical is one to four carbon atoms when a is 2 and one to eight carbon atoms when a is 1.

20. The composition of claim 13 wherein the lower alkyl radical is selected from the group consisting of methyl, ethyl, propyl, isopropyl and butyl.

21. The composition of claim 18 wherein the concentration of the aromatic ester is at least 0.4% based on the weight of the material to be dyed.

22. The composition of claim 18 wherein the con centration of the aromatic ester is from 1% to 6% based on the weight of the material to be dyed and said acid to adjust the pH of said fluid medium is acetic acid.

23'.- The composition of claim 18 further consisting of an effective amount of at least one non-ionic emulsifier.

24. The composition of claim 23 wherein the ratio of emulsifier to aromatic ester is 1: 1.2 to 1:3.4.

25. The composition of claim 23 wherein the concentration of the emulsifier and the aromatic ester is at least 0.4% based on the weight of the acrylonitrile polymer.

References Cited UNITED STATES PATENTS 3,124,412 3/ 1964 Fidel! et al 8-177 AB X 2,362,377 11/ 1944 Heymann 8-173X 23 94,689 2/1946 Heymann 8173 X OTHER REFERENCES I. E. Lynn et al., Advances in Textile Processing, vol. 1, 196-1, pp. 362-363, Textile Book Publishers Inc., New York, N.Y., 8-173 Lit.

GEORGE F. LESMES, Primary Examiner T. I. HERBERT, 1a., Assistant Examiner US. Cl. X.R. 8-177 AB