US3676050A - Aqueous dyeing of acid-dyeable polyamide fibers using yellow-to-orange disazo dyes - Google Patents

Abstract

IN AN AQUEOUS PROCESS FOR DYEING TEXTILE MATERIALS COMPRISED OF POLYAMIDES, PARTICULARLY DEEP-DYEABLE POLYAMIDES AND POLYAMIDE STYLING YARNS AND FIBERS, AT A PH OF 3-7 AND AT A TEMPERATURE UP TO THE BOIL, IN THE PRESENCE OF DYES AND DYEING ASSITANTS, THE IMPROVEMENT OF USING YELLOW-TO-ORANGE DISAZO DYES OF THE STRUCTURE

(2-HO,3-R1,5-R-PHENYL)-N=N-B-N=N-A

WHEREIN

A= (R2)N,(M-O3S-)PHENYL, OR (M-O3S-)NAPHTHYL

THE SO3M GROUP IN THE LATTER STRUCTURE BEING SUBSTITUTED IN EITHER AROMATIC RING OF THE MAPHTHALENE NUCLEUS; R2=METHYL, METHOXY, NHCOCH3, CL OR BR; N=3, 1 OR 2; M=H, ALKALI METAL OR AMMONIUM CATION;

B= (2-Y,5-Y-1,4-PHENYLENE), OR 1,4-NAPHTHYLENE

X AND Y=H, C1-2 ALKYL OR C1-2 ALKOXY; R=C1-5ALKYL, -NHCOC1-4ALKYL, OR , WHEN X(OR BOTH X AND Y) IS A SUBSTITUENT OTHER THAN H, CL OR BR; AND R1=H OR C1-5 ALKYL.

Description

United States Patent 3,676,050 AQUEOUS DYEING F AClD-DYEABLE POLY- AMIDE FIBERS USING YELLOW-TO-ORANGE DISAZO DYES Daniel S. James, Hockessin, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del. No Drawing. Filed Jan. 21, 1969, Ser. No. 792,783 Int. Cl. C09]: 31/04 U.S. Cl. 8-41 B 11 Claims ABSTRACT OF THE DISCLOSURE In an aqueous process for dyeing textile materials comprised of polyamides, particularly deep-dyeable polyamides and polyamide styling yarns and fibers, at a pH of 3-7 and at a temperature up to the boil, in the presence of dyes and dyeing assistants, the improvement of using yellow-to-orange disazo dyes of the structure wherein (R z) n the $0 M group in the latter structure being substituted in either aromatic ring of the naphthalene nucleus; R =methyl, methoxy, NHCOCH C1 or Br',

n=0, 1 or 2;

M=H, alkali metal or ammonium cation;

X and Y=H, C alkyl or C alkoxy;

R=C alkyl, NHCOC alkyl, or, when X (or both X and Y) is a substituent other than H, C1 or Br; and

This invention relates to dyeing of polyamide textile materials, particularly deep-dyeable polyamides and polyarnide styling yarn and fibers as hereinafter defined. More specifically it relates to an improved dyeing process employing specific yellow-to-orange, disazo, acid dyes.

As is true in any area of intense commercial activity, some significant modifications have recently evolved in the dyeing of nylon, and particularly in the dyeing of nylon with disazo dyes as described in U.S. Pat. 3,485,814. Another example illustrating the rapid developments in the field of nylon dyeing, particularly nylon carpets, is described in an article in the American Dyestuff Reporter by J. A. Brooks et al., pp. 68-72, Nov. 20, 1967. This article further describes the use of nylon fibers having different aflinities for acid dyes to obtain styling effects in piece dyeing.

For a dye to be commercially attractive for dyeing nylon (i.e., synthetic polyamides), the dye must certainly have afiinity for nylon, and have at least a minimum degree of lightfastness. It would be desirable, moreover, for nylon dyes to possess the quality known as tranfer; that is,

3,676,050 Patented July 11, 1972 the ability to equilibrate effectively between dyed and undyed filaments. In the particular application of styling carpets, due to the carpet construction and placement of the differential dyeing nylon fibers, transfer is of lesser importance than when the carpet to be dyed is constructed from yarn of uniform dyeability.

The generally accepted mechanism for dyeing nylon with acid dyes, normally carried out at a ptl-I of 4-6, may be summarized by the following equations:

69 9 nylon-NR2 H 0 3 nylonNH H20 nylon-NHa O S-dye These equations illustrate that the dye sites are the free amine end groups. These free amine end groups, being basic, may be protonated in acidic solution to yield positively-charged ammonium groups. In this positivelycharged form, they serve as sites, by interionic attraction, for the anionic dye molecules.

Thus, if nylons are to be prepared with varying degrees of dyeability, this may be accomplished by controlling the number of free amine ends in the nylon polymer, i.e., by varying the ratio of diamine to dicarboxylic acid monomer in the preparation of the polymer. Thus nylon fibers are now available which contain various amounts of free amine groups and thus varying degrees of dyeability with acid dyes, e.g.,

(A) Fibers containing about 5-25 gram-equivalents of free amine groups/10 grams of polymer which are only lightly dyeable with acid dyes;

(B) Fibers containing about 25-55 gram-equivalents of free amine groups/.10 grams of polymer which may be dyed with acid dyes to a medium depth; and

(C) Fibers containing about 55-120 gram-equivalents of free amine groups/1O grams of polymer which are heavily dyeable with acid dyes (see for example Ben, U.S. Pat. No. 3,078,248).

An unusual problem has arisen in dyeing type (C) fibers (i.e., the deep-dyeables), especially in dyeing styling yarns and fibers as are formed in carpeting, i.e., carpeting containing each of the three above acid-dyeable fibers and basic (cationic)-dyeable nylon fibers as taught, e.g., in Magat, U.S. Pat. No. 3,184,436. Surprisingly, it has been found that when deep-dyeing nylon is present, certain dyes normally useful for dyeing nylon carpets (as those in the aforementioned U.S. Pat. 3,485,814, exhibit a serious deficiency. This deficiency manifests itself as a shade change and decrease in dye lightfastness. To illustrate, some available yellow dyes yield lightand mediumyellow shades on the lightand medium-dyeable nylons with good lightfastness. On deep-dyeable nylon, however, when a heavy-yellow shade would be desired and expected, the actual dyeing is not on tone, but much redder in shade and the lightfastness markedly decreased. This shade-shift and poor lightfastness is unacceptable to the trade.

The reason some dyes exhibit a shade change on deepdyeable nylon is assumed to be due to the basic conditions of the fiber. In forming nylon polymer from diamines and dicarboxylic acids, e.g., hexamethylene diamine and adipic acid, both free amino and free carboxyl groups are predicted as possible end groups. Now, with both lightand medium-dyeable nylon, as described above, the number of free carboxylic acid groups apparently exceeds the number of free amine groups.

With deep-dyeable nylon, however, it appears that the number of free amine groups exceeds the number of free carboxylic acid groups; thus, the pH of deep-dyeable nylon is apparently above 7. Moreover, the fiber basicity of deep-dyeable nylon appears suflicient to remove a Now, in the presence of deep-dyeable, basic nylon, apparently the phenate form of the dye is formed by removal of a proton, as follows: 10

To the extent that the above reaction occurs, the dyes shade will be altered since a phenate dye will have a diiferent electronic distribution and absorption spectrum than a dye with an nonionized phenolic group. Indeed, it would appear that when the phenate form of the dye is formed, the shade shifts from yellow or orange towards red and dye lightfastness decreases. It should also be pointed out that only a minor shade shift, that is to say, only a few phenate dye molecules need be formed, to give an unacceptable and noticeable shade change and poorer lightfastness.

As the above equation indicates, undesirable shade changes might be expected with certain dyes in the presence of other basic agents. In the trade, certain finishing treatments for woven and knitted nylon textile goods, and certain scouring procedures for dyed carpets, apparently contain amines which are substantive to nylon. When these amines are absorbed by nylon, since they are basic, they may also produce the deleterious shade change and reduced lightfastncss with some acid dyes.

Therefore, the objectives of this invention include providing dyes for dyeing nylons without significant shade shifts; providing dyes for dyeing nylons with adequate afiinity for and lightfastness on nylon fibers; and providing dyes for dyeing nylon which are unaffected by conventional basic finishing or scouring procedures.

BRIEF SUMMARY OF THE INVENTION These objectives and others are fulfilled by providing, in an aqueous process for dyeing polyamide textiles, particularly deep-dyeable nylons containing about 55-120 (usually 80-90) gram equivalents of free amine groups/ grams of polymer, at a pH of 3-7 and at a temperature up to the boil, in the presence of acid dyes and dyeing assistants, the improvement consisting of using, as said acid dyes, yellow-to-orange disazo dyes of the following structure: 5

r AN=NB-N=NC wherein (112M A: or Q R =inethy1, methoxy, NHQOCH C1 or Br;

4 n=0, 1 or 2 (where the R groups may be the same or different); M=H, alkali metal or ammonium cation;

X and Y=H, C alkyl or C alkoxy;

R=C alkyl, --NHC0C alkyl, or, when X (or both X and Y) is a substituent other than H, C1 or Br; and

As a preferred embodiment, the above improvement is applied to the process of dyeing textile materials comprised of polyamide styling yarns or fibers, especially those containing bulked continuous filament deep-dyeable polyamides, wherein the material is immersed for about 10-180 minutes in an aqueous dye bath maintained at a pH of 3-7 and at about 70-100 C.; which bath contains acid and basic type dyes and about 0.05 to 0.50% by weight of a sulfobutaine of the structure:

wherein R =an acyclic aliphatic hydrocarbon radical containing 7-17 carbon atoms;

m=an integer of 0 to 3;

p=an integer of 0 to 3; and

m+p=less than 4.

CHa; a, is -11; A is NaOaS or G S O Na O C H3 I and B is C or 0-, as for example I CH3 I SO Na DETAILED DESCRIPTION OF INVENTION It has now been found that, in the dyeing of polyamide textile materials, especially styling yarns, =fibers and carpeting containing deep-dyeable nylons, that the use of the yellow-to-orange disazo dyes as above defined significantly reduces the shade shifts resulting with heretofore employed disazo acid dyes. While the invention is not to be limited by discussions of the mechanisms involved, it is suggested that the improvements attained with the subject dyes are probably due to the positioning of the phenol hydroxyl group in a position ortho to the azo linkage where it may hydrogen bond therewith, i.e.,

thus rendering the subject dyes more resistant to the tendency to be converted to their phenate form by the basicity of deep-dyeable nylons.

Textile materials By polyamides (or nylons) are included those synthetic linear polycarbonamides characterized by recurring amide linkages as an integral part of the main polymer chain such as poly(hexamethylene adipamide), poly(hexamethylene sebacamide), poly(m-xylene adipamide), poly- (p-xylylene sebacamide), polycaprolactam and the like as well as copolyamides. Poly(hexamethylene adipamide) constitutes the preferred polyamide.

Polyarnides are utilized in many textile applications, specifically for preparing woven and knitted goods, etc. Nylon has, of course, also found great acceptance in the carpet market. In all the marketing potentialities known, e.g., carpets, upholstery, hosiery, apparel, parachutes, etc., the use of differential dyeing fibers has commercial significance. That is, by constructing textile goods from nylon fibers of differential dyeability, appealing tone-ontone styling effects can be obtained.

For the large carpet market, bulked continuous filament (BOP) polyamide has been widely acepted for constructing economical tufted carpets. BOP polyamide constitutes a preferred substrate for the process of this invention. BCF polyamide may be prepared, i.e., jet-bulked, with the jet taught by Hallden et al. in US. Pat. No. 3,005,251.

Additional styling effects, again especially significant for the carpet market, are achieved in the trade by combining, with the three differential acid-dyeable nylon fibers discussed above, cationic-dyeable nylon. With this type of construction, obviously, dyers are permitted even greater styling variations since multicolor dyeings can be made. As one very simple illustration, a carpet construction may be assumed as follows:

Repeat Repeat Pattern i Llght i Medl I Heavy i i Pattern Aid Dyeable Basic Dyeable Since the four yarns are available, a carpet manufacturer might tuft the yarns, either on jute or a synthetic backing as polypropylene. Now acid dyes are available which are attracted only to the acid-dyeable fibers, panels, or rows. A dyer might, for example, elect a yellow acid dye for the acid-dyeablc portions. If done on our simple pattern above, strips or rows of light-, medium-, and heavyyellow would be produced, with negligible color on the basic-dyeable nylon. Now, if the dyer so desired, he could simultaneously add selected cationic (basic) dyes and obtain an entirely different shade on the basic-dyeable nylon, e.g. blue, green, red, black, etc. Such available basic dyes which may be applied include Sevron" Yellow 3RL (OI. Basic Yellow 15); Sevron Yelloiw MFW (C.I. Basic Yellow 31); Sevron Orange CL (Cl. Basic Orange 25); Sevron Red L (Cl. Basic Red 17); Sevron Blue B (C.I. Basic Blue 2.1); Sevron Blue 2G (Cl. Basic Blue 22); and the like.

This simple illustration hopefully conveys the principle of differential dyeing and its importance for opening up an almost infinite number of styling effects (i.e., toneon-tone, dyed-undyed, mutlicolored) available for nylon in textile applications. Basic-dyeable nylons have been described in US. Pat. No. 3,184,436. Nylon, heavily-dyeable with acid dyes, has been described in US. Pat. No. 3,078,248.

'In the hypothetical pattern discussed above, if it is assumed that we have used, as our yellow dye, a dye of we would have been disappointed since a deep-yellow shade would not have been obtained; indeed, that portion would be red with poor dye light fastness. The potential attendant problems are obvious, i.e. prospects of achieving an unappealing, perhaps even clashing, dyed textile, etc. By using the dyes and the process of this invention, these unsatisfactory results may be substantially avoided.

It is to be understood that a broad class of polyamides may be employed as substrate in this invention. Several polyamides have been described by Ben in US. 3,078,248, for example polyhexamethylene adipamide, poly(2-methylhexamethylene oxamide), polycaprolactam, the polymer derived from m-xylylene diamine and adipic acid, etc. Polyhexarnethylene adipamide appropriately modified with various antistatic additives, U.V. screeners, etc., and polyamides prepared from 4,4-bis-aminocyclohexylmethane and dodecanedioic acid may also be dyed by the appropriate dyeing procedures.

The dyeing process is aqueous and may conveniently be carried out using per part of textile material, 20 to parts of water without effect on the process efficiency. The amount of dye assistant (e.g., disodium dodecyldiphenyl ether disulfonate) used may be varied from 0.5% to 4.0% by weight, although .5 to 2% is the preferred amount. Lesser amounts are insufficient to insure satisfactory leveling and streak coverage. Amounts greater than 4% may lead to poor exhaust from the dyebath and consequent economic loss, and also has caused a diminution of lightfastness. Dyeings may be carried out at a pH from 3 to 7, but experience has shown the most favorable results with nylon fibers containing up to about 100 gram-equivalents of free amine groups/ 10 grams of polymer occurs with the pH at 6 to 7. Higher pH causes poor exhaust, the dye tending to stay in the bath rather than attaching itself to the nylon. On the other hand, with nylon fibers containing more than 100 gram-equivalents of free amine groups/10 grams of polymer, it is most desirable that the pH of the dye-bath not be allowed to rise above about 6 for at least the greater portion of, and particularly at the termination of, the dyeing process. In dyeing such ultra-deep-dyeable nylons (i.e., 100-120 gram-equivalents) at a pH much greater than about 6, while there is no problem with lightfastness, the subject dyes will tend to undergo dulling shade changes. This tendency to undergo a dulling shade change of pI-Is much greater than about 6 occurs, in spite of the greater shade stability of the dyes of the instant invention over those containing a hydroxyl group para to the azo linkage, because there is a limit to the basicity of the substrate (unless the pH is kept below about 6) beyond which even the subject dyes tend to undergo a drilling shade change.

While the temperature may be up to the boil, the optimum temperature for the dyeing process is 95 C. to 100 (3., most test dyeings being carried out at 98 C. Lower temperatures extend the time required and also give poor exhaust.

In the above process, an alkaline detergent prescour may have also been performed to remove finishing oils, dirt, etc. Moreover, frequently a nonionic surfactant, the condensation product of a C alcohol with 10 moles of ethylene oxide, is coemployed as dyeing assistant. The concentrations effective vary from approximately 0.25 to 2%, with 0.5% being a preferred concentration, The requisite acidic pH is usually attained by using acetic acid and phosphate buffers, as mono'sodium phosphate. Also, in lieu of the anionic dyeing assistants above, others disclosed in US. Pats. 2,081,876 and 2,854,477 may be employed. Finally, conventional metal sequestering agents and antifoam agents may be added, the sequestering agents being especially preferred when X is alkoxy in the disazo dyes. Versene (ethylenediaminetetraacetic acid tetrasodium salt) constitutes a preferred sequestering agent.

The above process is one which promotes optimum dye transfer, i.e., equilibration between dyed and un-dyed nylon. It would be expected to yield an essentially equidepth of shade even across the entire face of a 15 ft. width carpet.

The subject processes may of course also be used in the absence of deep-dyeing nylon. The basic dying procedures described herein are, of course, well-known in the art, as described in the various cited references.

In dyeing styling yarns and fibers (i.e., those containing both acidand basic-dyeable nylons) to obtain contrasting multicolor carpets, a bleach scour of the nylon is preferred as the first step. This aqueous scour, in a weight ratio of generally about 20-40: 1, includes approximately 4% sodium perborate, approximately 1/ 5 trisodium phosphate, and approximately of the betaine described below. The bath temperature is raised to approximately 160 F. and held there approximately 15 minutes. The bleach-scour bath is then discarded and the carpet rinsed with warm water; the carpet is then ready for dyeing.

The dyeing process may be successfully carried out with dyebaths having pH values of from 3 to 7, however the most favored pH is 6.0 to 6.2. At this value satisfactory exhaust of both acid type and basic type dyes is attained. Either lower or higher pH may lead to poorer exhaust and less then optimum constrast.

The sulfobetaine dyeing assistant may be used in amounts as low as .05 of the weight of fiber being dyed, the best results being obtained with .2% to 3%. Amounts of dyeing assistant larger than .5 of the weight fiber dyed have led to staining and less eifective reserve of the non-dyed fibers.

-It is very important that dyeing be carried out at temperatures above 70 C., the best results being obtained at temperatures near the boil (95 -100 0.). Lower temperatures will give inferior exhaust, staining of the undyed fibers and poor contrast.

The sulfobetaines used in the process of this invention may be prepared from commercially available tertiary amines having one fatty aliphatic hydrocarbon group (derived from various fatty sources having mainly from 8 to 18 carbon atoms) and 2- polyoxyethylene groups attached to the nitrogen as in the following general formula:

where R is an acyclic aliphatic hydrocarbon having 7 to 17 carbon atoms and m and p are integers of from 0 to 3 but the sum of m and p is no more than 3.

8 Methods of preparing both sulfobetaines and their precursors are described in U.S Pat. 3,280,179.

The sulfobetaines used in the process have the structure:

wherein R is an acyclic aliphatic hydrocarbon radical of from 7 to 17 carbon atoms, in is from 0 to 3, p is from 0 to 3 and the sum of m and p is no more than 3. Its functions are to prevent precipitation of cationic-anionic dye complexes, to promote leveling of both species without suppressing buildup, and to minimize cross staining.

The bleach scouring process is also known as described more fully in the defensive disclosure of Robbins, Ser. No. 634,477 dated Apr. 29, 1969 (861 0.6. 1355).

Finally, using the above described processes with any type of nylon textile, dyeing is usually followed by conventional rinse and drying steps. Moreover, especially in the carpet area, conventional finishing, drying, latexing, and double backing application may be performed by customary means.

It is to be understood that the dyeing procedures of this invention may be performed in conventional equipment. Thus, carpeting is usually dyed in becks; upholstery is usually dyed in jigs; accent on throw rugs are usually dyed in paddle machines.

The recently developed continuous dyeing of carpets employs differential dyeing yarns, and thus is also benefited by the subject invention, References to this new technique are found in Melliand Textilberichte, 48, 415-448 (April 1967).

The recent art teaches that continuous carpet dyeing is related to piece dyeing in that it is an aqueous dyeing but (a) at very low bath ratios, 5:1 instead of 30:1 to 50:1, and (b) that the rate of fixation is much faster because temperatures near the boil are attained more quickly in a steamer than in heating up a beck.

Dyes.The disazo, acid dyes applicable by the previously described processes to deep-dyeable nylon which fulfill the objectives of this invention, are characterized by possessing, in the final coupler, a phenolic hydroxyl ortho to the azo linkage. Coupling only into the ortho position is a consequence of using, as final couplers, selected parasubstituted phenols. The structure of the dyes is as follows:

wherein A, B, R and R are as defined above.

Some of the dyes, falling within the above generic formula, are old, having been described in French Pat, No. 1,201,549, as intermediates for subsequent metallization to yield metallized, acid dyes.

The preparation of the dyes useful in this invention is essentially the same as that described in the above French patent. That is, an aminoaryl-sulfonic acid, A, is diazotized and coupled to an aromatic amine, B, to yield 9 an aminoazo intermediate. Finally, the aminoazo intermediate is diazotized and coupled to the final coupler, a para-substituted phenol.

Since most of the intermediate monoazo compounds are readily available, the actual preparattion of the disazo dye often is complete in one step. For example, the preparation of a preferred dye useful in this invention involves only the following:

The synthesis of the preceding disazo, acid dye would involve the following steps:

The coupler may be prepared by adding 30% caustic soda (105 parts) to 5000 parts of water and adjusting the temperature to 25 :1 C. Then, with agitation, 284 parts of p-cresol and 50 parts of soda ash are added; complete solution occurs. The coupling solution is stirred until the diazo is ready; when the diazo is ready, the coupler solution is cooled to 10:2 C.

The preparation of the diazo is initiated by adding 4- aminoazobenzene-4'-sodium sulfonate (715 parts) to 4000 parts of water, stirring until a smooth slurry is obtained, followed by the addition of sodium nitrite (182 parts). The temperature is held at 32:1 C.

In another vessel, hydrochloric acid (262 parts) is dissolved in water (5500 parts) and the temperature adjusted to 32:1 C. Then, the sodium nitrite-aminoazobenzene sulfonate slurry is added with agitation to the acid solution over a period of 25:5 minutes; the temperature is allowed to rise. After stirring at 35:1 C. for 30:5 minutes to complete the diazotization, excess nitrite is destroyed with sulfamic acid and the diazo solution cooled to 10:2 C.

Coupling is effected by adding the above diazo, with strong agitation, to the p-eresol coupler solution over a period of 40:5 minutes at 10:2 C. The product (the disazo dye) forms as a thick orange brown precipitate. The product is isolated by allowing the reaction mixture to warm to 25 C., filtering the product, and washing the dye with a minimum of water. The dye may be dried at any convenient temperature up to 100 C.

The dry crude dye may be standardized by finely grinding the dye with Blancol (the sodium salt of a sulfonated naphthalene-formaldehyde condensate) or preferably with a mixture of dextrin and trisodium phosphate.

Other aminoazo compounds readily available, and thus useful in a process similar to the above, include m- (p-aminophenylazo) benzenesulfonie acid and m-(4- amino-3-methoxyphenylazo) benzene sulfonic acid.

All of the dyes useful in the present invention, including the above, can be prepared as described in French Pat. 1,201,549. That is, ANH is diazotized and coupled to BNH then the intermediate aminoazo compound, AN=NBNH is further diazotized and coupled to the selected phenols. The following 10 compounds are suitable for A-NHz, B-NH and coupler:

A-NH Compounds:

aM SIOaM OCH:

NHz, N Hz, NH:

| l S 03M 8 OzM ('31 (3111 ISOaM SIOZM CH NH: and NH2 wherein M=I-I, alkali metal or ammonium cation.

B-NH Compounds:

OCH; OCH;

i ONH: and

l I a NHCOCH; NHCOC H CHa-C-CHa When X or X and Y are permissible substituents other than H, particularly alkoxy, the final coupler may also be selected from p-chlorophenol and p-bromophenol.

Disazo dyes prepared from the above do not exhibit the strong red shift on dark-dyeable nylon as do the isomeric p-hydroxyl substituted dyes such as the following:

S O Na and (I) C Ha 3 OaNa The subject disazo dyes yield yellow-to-orange shades on polyamides which fulfill the objectives of this invention. It is to be understod that the subject dyes may be used either alone, to form single shades, or in combination with other acid, disperse, metallized, and/or cationic dyes to yield mixed shades, tone-on-tone, multicolored, etc. dyeings. That is, the presence of other dyes or customarily used dyebath additives do not interfere with the subject dyes fulfilling the objectives of this invention.

The acid dyes prepared according to the examples are shown in the form of their sodium sulfonates. It will be understood that the dyes of this invention may also be prepared and used in their free acid form or as their alkali metal or ammonium salts. For instance, in Example 1 the NaOH and Na CO may be replaced by chemical equivalent amounts of KOH and K CO respectively, to provide the potassium sulfonate form of the dye. Similarly, the lithium sulfonate of the dyes may be prepared.

In order to obtain the dyes in the form of their free acids an aqueous slurry of the dye is made strongly acid with hydrochloric acid and then warmed with stirring. The insoluble acid form of the dye is then filtered off and washed with warm water.

The ammonium salts of the dyes may be obtained by dissolving their free sulfonic acids in aqueous ammonium hydroxide followed by salting out their ammonium sulfonates with ammonium chloride or ammonium sulfate.

EXAMPLES The following examples are offered to illustrate the subject invention and are not intended to be in limitation thereof.

(A) PREPARATION OF DYES Example 1Preparation of SO N8. Ha

Phenylazoaniline-m-sodium sulfonate (75% pure, 20 g., 0.05 mole) was dissolved in water ml.) by warming to 40-50 C. 5 N-sodium nitrite (11.5 ml., 0.057 mole) was added. The solution was added to a stirred mixture of 10 N-hydrochloric acid (16 ml., 0.16 mole) and water (50 ml.) over a period of 10 minutes at 35 40 C. After holding a positive nitrite test at 3540 C. for a further /2 hour, the diazonium salt was cooled to 5-10 C. by adding ice. It was then added over 10-15 minutes to a stirred solution of p-creso-l (5.9 g., 0.055 mole) and sodium carbonate (12.5 g.) in water g.) and 30% sodium hydroxide (5.5 ml., 0.055 mole) which had been cooled to 5-l0 C. with ice.

The product was filtered off and dried at 75 C. Thin layer chromatography (T.L.C.) was used to determine the purity of the dye. The eluent used was butano1:acet0ne:water:ammonia=5:5: 1:2, and the plates were coated with silica gel. Dry wt.=24 g.

Example 2-Preparation of The above dye was prepared as in Example 1, but substituting an equivalent weight of 4-.aminoazobenzene-4- sodium sulfonate for phenylazoaniline-m-sodium sulfonate. The disazo dye obtained has the following absorption characteristics: A (wavelength of maximum absorption)=360 111 4; absorptivity (i.e., absorbance per unit length divided by concentration)=85.0/g.

Example 3Preparation of l SO NE The above dye was prepared as in Example 1, but substituting an equivalent weight of 3-methoxy-4-aminoaz0- benzene'3-sodium sulfonate for phenylazoaniline-m-sodium sulfonate. The spectral data are X =360 (420) m absorptivity=56.4/ g.

Example 4-Preparation of (I) C H3 $11 A) S OzNu C H: C Ha 2,5-dirnethoxy-4-aminoazobenzene-3'-sulfonic acid (18 g., 94% pure, 0.05 mole) was dissolved in water (100 ml.) and 30% sodium hydroxide (5 ml., 0.05 mole). 5 N- sodium nitrite mL, 0.1 mole) was added and the solution added over a period of 2 /2 hours to a stirred mixture of 10 N-hydrochloric acid mL, 0.3 mole) and water (150 ml.) at 5055 C. Addition was carried out beneath the surface of the acid to inhibit foaming due to decomposition of nitrous acid. After a further /2 hour, the diazo was cooled to 5-10 C. with ice. The coupling procedure was as described above in Example 1.

Example 5-Dye characterization The following table provides dye evaluation and characterization data for the dyes of Examples 1-4 and 12 other dyes both within and outside the scope of this invention. The 12 other dyes were prepared by comparable methods. Dyes numbered 1, 16, 6, and 11 correspond to Examples 1-4, respectively. Dyes numbered 2, 3, 8, and 13 are outside the scope of this invention and give an unacceptable red and dull shade on deep-dyeable nylon versus medium-dyeable nylon. The remaining dyes support the scope of this invention. Redness and dullness are associated with the formation of the phenate ion, with concomitant drastic loss in dye lightfastness. The apparent brightness and strength of the dyes of this invention (e.g., Nos. 1, 4, 6 and 7 in Table I) on deep-dyeable versus medium-dyeable nylon is probably due to their better exhaust on the former versus the latter fiber. The yellowness of other dyes falling under the scope of this invention (e.g., Nos. 5, 11 and 12 in Table I) on deep-dyeable vs. medium-dyeable nylon is quite acceptable, since there is no observable accompanying loss in dye lightfastness.

TABLE I.ACID DYES FOR NYLON STYLING CARPET Shade deepdyeable vs. Lightfastmedium Trans ness ratings dyeable fer, 1 2 after 80 hrs., BCF Dye No. Dye Shade 1 Exhaust 1 percent Xenon 1 a nylon 4 1 OH Bright Fair-good... -45 5 3S.

orangeyellow. N=N- N=N l l S OiNa CH;

2 OH Orange- Good. 1D.

1 yellow.

l l S OaNa Cl 3 ('31 d0 Fair-good IE.

I S O Na 4 H? (3H3 d0 Good 30-35 6-4 Br 38.

I I S OaNa CH3 5 H? tl-butyl do Fair 2Y, Br.

I S OaNa t-butyl 6 0 OH; HO Orange- Good 5-4W 2 1 Br.

I brown I S O=Na CH3 7 ()CHs ()H do ..d0- 21 Br.

I S OaNa C1 8 OCH: O1 Orange- Fair-poor. 1R.

1 l yellow:

l S O Na See footnotes at end of table.

TA B111 IConti nucd Shade deepdycable vs. Lightfastmedium Transness ratnigs dyeable fer, 1 2 after 80 hrs., BCF

Dye No. Dye Shade 1 Exhaust 1 percent Xenon 1 3 nylon l 9 CH H0 CH3 Orange- Good 2-1 Br.

I I l brown.

I l S O3Na CH:

10 (ROI-I H? ti-butyl -do. Fair I S OiNa t-butyl 11 (|)CH3 OH Red Fair-good... 3-2W 3Y, Br, S.

Q Q -Q i i S 0311 0 CH3 CH:

12 fiJCH: OH Bed Fair 3Y, Br, 5.

l l S 03H 0 CE Cl 13 OCH; )1 Orange Poor Dull violet.

l S 03H 0 CH;

14 (30113 H? (3H Red Fair-good 3Y, Br, S.

I 1 S 0311 0 011a CH;

15 OOH; HCI) t-butyl Red Fair 3S.

\ S 0311 0 CH3 t-butyl 16 OH Bright orange- Fair-good -45 6-4YW 3S.

1 yellow.

l CH3 1 The shade, exhaust, transfer, and lightiastness ratings were obtained on carpeting made by tufting nylon yarn onto either a jute backing or a spunbonded, polypropylene backing. The BGF nylon yarn used for this is 3,700-dem'er, 204-continuous filaments, trilobal, jet-bulked yarn, melt-spun from polymexamethylene adipamide) flake. The yarn is jet-bulked with the jet taught by Hallden et al. in U.S. Pat. No. 3,005,251. The nylon is considered tonhe medium dyeable since it contains approximately 40 gram equivalents of free amine groups/10 grams of nylon. The dyeing procedure used was as o ows:

Thirty parts of the above carpeting (polypropylene) backing are installed in dyebath equipment. First, it is helpful to scour the carpet at 180 F. (82 C.) for 20-30 minutes in a bath made up of 1,000 parts water, 0.2 part of a nonionic surfactant (the condensation product of 20 moles of ethylene oxide with one mole of Ora alcohol), 0.6 part concentrated ammonium hydroxide and 0.15 part sodium hydroxide. The bath is dropped and the carpet is rinsed with clean water. A dyebath is then made up of 1,000 parts water, 0.85 part of dodecyldiphenyl ether disulionie acid, disodium salt (U.S. Pat. N o. 2,081.876), 0.03 part of the acid dye, 0.6 part of monosodium phosphate and 0.5 part of a nonionic surfactant, the condensation product of a Cir alcohol with 10 moles of ethylene oxide. The pH is adjusted to 6.0 by addition of acetic acid or disodinm phosphate (whichever is necessary). The bath temperature is raised to 210 F. (99 C.) over minutes and the dyeing is continued for one hour. The bath is dropped and the carpet is given a warm water rinse.

When the pH of the dyebath is adjusted to 6.5, instead of 6.0 as in the present example, similar results are obtained.

Any of the dyes of the present invention may be applied in this manner to give yellow to orange shades.

In lieu of the leveling agent used in this example, others disclosed in U.S. Pats. 2,081,876 and 2,854,477, may be employed.

Wool and silk may also be dyed in fast yellow-to-orange shades by the process of this example.

2 Transfer is ameasure of a dyes ability to equilibrate between dyed and undyed yarn. Thus, aloop of nylon carpeting as in note 1 above is dyed with the candidate dyes by the above procedure. Then hall the dyed loop is removed and a fresh, undyed, equal weight portion of nylon carpeting is sewed in to recreate the loop. Then, this loop goes through the dyeing cycle again, but without the addition of fresh dye. In this process, some dye will enter the dyebath from the dyed goods, and thus be available for dyeing the fresh, undyed nylon. Thus, the original dyed nylon will be stripped down and the fresh nylon become dyed. Perfect transfer or equilibriation is evidenced by a strip-down of on the original dyed goods, with both the dyed and fresh, undyed nylon becoming dyed to equal depths at the end of the simulated dyeing cycle. Thus, the optimum transfer is 50%. Usually, a transfer of 40-45% is required to achieve level dyeing over a 12-15 ft. wide commercial nylon carpet.

a The lightfastness ratings are in accordance with the A.A.T.C.C. and International Gray Scale (see scale under Example 7). The Xenon Arc and 80 standard fading hours exposure are also in accordance with accepted A.A.T.C.C. standards.

4 This test involves comparing the shade change on deep-dyeable nylon, i.e., containing approximately 80 gram equivalents of free amine groups/10 grams of polycarbonamide polymer as described in U.S. Pat. No. 3,078,248, versus medium-dyeable nylon, as defined in note 1. Shade change ratings are again based upon well-known A.A.T.C.C. Gray Scale methods. (See ratings under Example 7.)

(B) PROCESS OF DYEING in Width, prepared with the following poly(hexamcihylcne adipamides): Example 6 (a) Cationic-dyeable, 1300 denier, such as described in U.S. Pat. No. 3,184,436; In this example, the carpet was multifiber BCF nylon (b) Medium-dyeable, 3700 denier; and yarn tufted onto a non-woven polypropylene backing. (c) Decp-dyeable, 3700 denier, as described in U.S.

The carpet consisted of three bands, each one six ends Pat. No. 3,078,248.

CHQCHZOH R-N-CHzCHzCHzSQ:

CHzCHzOH where R:

C16 is C monounsaturated (40% and 0.25 part of trisodium phosphate. The temperature was then raised to 160 F. for 15 minutes. The carpet was rinsed in warm water at 100 F.

Dyeing.100 parts of carpet were heated for 10 minutes at 80 F. in 4000 parts of water containing 0.25 part of the aforementioned sulfobetaine and sufficient monosodium phosphate to adjust the pH to 6.0-6.2. 0.1 part of the dye of Example 2 was added and the dyebath temperature raised at 23 C. per minute to 208 R, which temperature was maintained for 1 hour. The carpet was rinsed and dried.

The results are tabulated under Table II following Example 7.

Example 7 The process of Example 6 was repeated using 0.18 part of the following dye (outside the subject invention):

1 SOaNa Table II gives the results of Examples 6 and 7:

TABLE II Liglitl'astness* (shade change) Shade on exposure to Xenon Arc depth 80 Standard Fading Hours Shade (b) vs. Stain Ex (0) vs. (b) percent on (a) (c) (b) (a) 6 25 5 5-4B R 5 5 7 1D 25 5 2-4BR 5 5 The numbers and letters in the table (as Well as in Table I above) correspond to accepted A.A.T.C.C. and International Gray Scale ratings as follows-Degree of alteration in shade and strength: Class 5=Negligible or No Change; 4=Slight Changed; 3=Noticeably Changed; 2=Considerably Changed; 1=Much Changed; BR=Brighter; BL=Bluer; D=Duller; G= Greener; M=Monotone; R=Redder; S=Stronger; W=Weaker; Y=Yell0wer.

NOTE.-(C) indicates deep-dyeable component; (b) indicates mediumdyeable component; (21) indicates cationic (base)-dyeable component.

18 Example 8 Nylon taffeta, prepared with medium acid-dyeable poly (hexamethylene adipamide), was dyed by conventional means with the dyes of Example 2 (2.0% standardized dye, O.W.F.) and a mixture of related isomeric dyes. The mixture of isomeric (non-invention) dyes was used to obtain a comparable shade to Example 2, and was prepared with essentially equal weights of the following dyes (where O.W.F. indicates on weight of fiber):

SOENB [0.98% standardized dye, O.W.F.] and II. (|)CH3 I r l SOQNQ [0.96% standardized dye, O.W.FJ

Then, the shade stability of the dyed nylon tafieta to various alkaline and amine chemicals was determined. The data is shown in Table III, where the numbers and letters pertain to A.A.T.C.C. standards described in Example 7:

TABLE III (A) Dyed with mixture (I and II, noninvention dyes) Heat treated for 15 min. at 320 F.

Soaped 1.0% 10 min. acetic Imme- One Imme- Gold at acid Treated withdiately day diately rinse 120 F. rinse 10% soda ash 3R 2D 2D 32D 3-2D 3D 1% caustic 3D 3-2D 2D 3-2D 3-2D 3D 5% urea 5 5 5 5 5 5 5% Avitex Rt. 5 3W 4R1D 2D 5-4D 2D Conc. NH'ZOHZ Wet, v.m. hlk Dry 5 5 5 5 6 5 (B) Dyed with Example =2 dye (dye of this invention) 10% soda ash- 3R 5 4D 5 5 5 1% caustic 3D 5 4D 5 5 5 5% urea 5 5 5 5 5 5 5% Avitex" R' 5 3 5 3D 2W 3-2D Cone. NH4OH:

Wet 1 hlk Dry 5 5 5 5 5 5 *Avitex R is listed as a complex higher alkylamine comgositlop in McCutcheons Detergents and Emulsifiers, 196'7 nnua The above data show that, surprisingly, the improved dyeing process of this invention yields dyed nylon goods with superior stability to various alkaline and amine chemicals, compared to nylon goods dyed with isomeric dyes.

Example 9.Dyeing with use of metal sequestering agent Deep-dyeable nylon yarn, as described by footnote 4, Table I, was dyed essentially as described in footnote 1, Table I. That is, parts of deep-dyeable nylon yarn, 0.85 part of dodecyldiphenyl ether disulfonic acid, disodium salt (US. Pat. No. 2,081,876), 2 parts of monosodium phosphate, 0.5 part of a nonionic surfactant, the condensation product of a C alcohol with 10 moles of ethylene oxide, and- 0.2 part of dye of Example 2, No. 16 of Table I, were added to 4000 parts water. The pH was adjusted to 6 with acetic acid and the temperature raised to 205210 F. This temperature was maintained for one hour, and the yarn then given a cold rinse.

A dyeing, as the above, was also made using 0.1 part of dye of Example 3, dye 6 of Table I. These two dyeings served to provide the controls.

The influence of trace metals was determined by repeating the above two dyeings with 0.2 part of cupric sulfate.

The efiicacy of metal sequestering agents for reducing the metal sensitivity of the two dyes was determined by repeating the above two dyeings in the presence of 0.2 part cupric sulfate and 1 part Versene 100 (a product disclosed to be ethylenediaminetetraacetic acid tetrasodium salt). The results obtained are given in Table IV as follows:

TABLE IV.EFFECT OF Cu AND METAL SEQUESTERING ON TWO DYES USEFUL FOR DEEP-DYEABLE Shade change Control Metal sensitivity Metal seques- Dye of (no Cu, tered (Ou+++ Example no Versene) (50 p.p.m. Cu) Versene 100 2 Oontrol 54D 5-4 Br 3 d0.-. Very much duller 3 Br Example 10.Dyeing ultra-deep-dyeable nylon The dyeing process described in Example 6 was repeated, using a multifiber BCF nylon yarn tufted onto a non-woven polypropylene backing, but consisting of four (4) bands. These included the three bands (a), (b) and (0), described in Example 6, with an additional band (d), six ends in width, consisting of an ultra-deep-dyeable nylon, 3700 denier, containing approximately 120 gram equivalents of free amine groups/10 grams of polymer, as described in US. Pat. No. 3,078,248.

The carpet was bleached and dyed with the dye of Example 2, according to the procedures in Example 6, care being taken to maintain the pH at about 6 during the dyeing process.

The dye distribution on the four bands was estimated to be as follows: (a) 0%; (b) 5%; (c) 25%; (d) 70%. There was no discernible dullness of shade on hand (d) versus band (0).

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for obvious modifications will occur to those skilled in the art.

What is claimed is:

1. In the aqueous process for dyeing textile materials comprised of acid-dyeable polyamide fibers prepared from the condensation of a diamine with a dicarboxylic acid at a pH at about 3-7 and a temperature of from 95 to 100 C. in a dye bath containing acid dyes and dyeing assistants, the imprvement consisting of using, as

said acid dyes, yellow-to-orange disazo dyes of the structure HO R;

wherein: A is selected from and SOaM

the M group in the latter structure being substituted in either aromatic ring of the naphthalene nucleus;

R is selected from methyl, methoxy, NHCOCH C1 or Br;

n is an integer from 0 to 2;

M is selected from H, alkali metal or ammonium cation; 1 B is selected from R is H and R is CH;,.

6. Claim 5 wherein the textile material is carpeting. 7. Claim 4 wherein A is l SOaNa R is H and R is CH;.;.

8. Claim 4 wherein A is s oaNa R is H and R is CH 9. Claim 8 wherein said dyebath also contains ethylenediaminetetraacetic acid tetrasodium salt;

21 22 10. Claim 3 wherein said dyebath has a temperature of References Cited about 95-100 C. and contains ethylenediaminetetraace- D N tic acid tetrasodium salt; R is -CH;;; R is H; A is UNITE STATES FATE TS Selected from 2,499,787 3/1950 Sharkey 821 B 5 FOREIGN PATENTS 1,201,549 7/1959 lFrance 260186 N'r10aS- and 6- 1,365,903 5/1964 France 260-186 1 1,161,717 8/1969 Great Britain 8-21 B SOsNB 10 1,469,779 12/1968 Germany s 21 B OTHER REFERENCES Douglas, Adr, Feb. 19, 1957, pp. 122 to 125. Egli, Textilveredlung, Feb. 11, 1967, pp. 8566,

and B is selected from 15 GEORGE F. LESMES, Primary Examiner G and C P. C. IVES, Assistant Examiner 11. Claim 10 wherein said textile material is poly- US (hexamethylene adipamide) carpeting. 2O 8- 2l B, 85; 260l84, 186, 187, 190, 191