US3520007A - Process of dyeing polyester fibers and products - Google Patents

Description

United States Patent 3,520,007 PROCESS OF DYEING POLYESTER FIBERS AND PRODUCTS Karl Schuster and Karlheinz Schneider, Ludwigshafen (Rhine), Germany, assignors to Job. A. Benckiser G.m.b.H., Chemische Fabrik, Ludwigshafen (Rhine), Germany, a German company No Drawing. Filed June 3, 1966, Ser. No. 554,993 Claims priority, application Germany, June 5, 1965, B 82,292; July 31, 1965, B 83,090 Int. Cl. D06p /04 US. Cl. 8-171 33 Claims ABSTRACT OF THE DISCLOSURE A method of treating polyester fibers and products thereof which involves using certain polyphosphoric acid compounds prior to or with the dyeing of the polyester to minimize or obviate the use of dye accelerant or socalled carriers. The products obtained and the dye baths for such treatments.

The present invention relates to a process of dyeing polyester fibers and textile materials containing same and more particularly to a method of dyeing such polyester fibers with the air of so-called carrier agents, and to polyester fibers dyed accordingly.

Polyester fibers are composed of macromolecules which are held together by strong intermolecular binding forces. These polyester molecules have a crystalline compact structure so that only very small amorphous areas of relatively minor extension, as they are required to permit the dyestuffs to diffuse therethrough are available in said fibers. Such fibers are also lacking chemical groups which are capable of combining with the dyestuff. For this reason such fibers are treated, usually during dyeing, with accelerants or so-called carriers, preferably at a temperature up to 100 C. Such dyeing aids or accelerants cause increased speed up of the rate of dyeing and allow production of heavy shades as well. Only when polyester fibers are treated with such carriers are dyed in their presence, is it possible to achieve satisfactory dyeing effects.

Treatment with the carrier as stated above, takes place during the dyeing procedure itself. Organic compounds of various structure are used as carrier. Suitable carriers are, for instance, aromatic hydrocarbons such as benzene, phenols, such as oor p-phenyl phenols, chlorinated aromatic hydrocarbons such as trichloro benzene, aromatic carboxylic acids or their esters such as benzoic acid, salicylic acid methyl ester, and aromatic ethers, such as chloro benzene ether.

Treatment with such carriers, however, has a number of disadvantages. They increase the costs of the dyeing process. Some of them are rather toxic. Others have a troublesome and irritating odor. Most of them can be removed from the dyed fiber with difficulty only. Further: more, they impair the color fastness to light when applied in an amount of about 2 g./l. to about 6 g./l. and more. There is also the danger that so-called carrier spots are formed on the dyed fiber material.

It is one object of the present invention to provide a simple and effective dyeing process for polyester fiber material, thereby considerably reducing or completely eliminating the disadvantageous effects of such carriers and very considerably improving the carrier properties.

Another object of the present invention is to provide dyed polyester fibers or textile material containing such fibers which fibers or material are free of the disadvantageous properties imparted thereto by proceeding according to the known process of dyeing such polyester fibers.

Other objects of the present invention and advantageous features thereof will become apparent as the description proceeds.

In principle, the process according to the present invention consists in treating the polyester fiber material with polyphosphoric acids or so-called ultraphosphoric acids or with metal salts of such polyphosphoric acids which correspond, for instance, to the following formula:

Substitution products of said polyphosphoric acids or ultraphosphoric acids may also be used, such as pyro phosphate esters and condensation products of urea and phosphorus pentoxide and mixtures of said acids and/ or their metal salts or/and their substitution products may also be added. It has been found that, when adding such polyor ultraphosphoric acid compounds to the dye bath, the amount of carrier can be greatly reduced or completely eliminated. For instance, half the usually employed carrier amount or even less is sufficient to produce dyed polyester fibers of about the same intensity when adding such polyor ultraphosphoric acid compounds to the dye bath. For instance, when adding 1 g./l. to 4 g./l. of said polyor ultraphosphoric acid compound, amounts of about 0.2 g./l to about 3 g./l. of carrier are sufiicient. It is evident that, by reducing the amount of carrier, the above mentioned disadvantages of the use of the carrier agent can be reduced or even completely eliminated.

Especially advantageous additives are polyphosphates such as disodium disphosphate, Graham salt (sodium hexametaphosphate). The so-called ultraphosphates with a proportion of Me O:P O being smaller than 1 have proved to be especially suitable for the purpose of the present invention.

As stated hereinabove, the polyor ultraphosphoric acids or their salts or substitution products are added to the dye bath in order to considerably improve the effec tiveness of the carrier.

It is, however, also possible to first pretreat the polyester fiber or fabric with the reduced amount of carrier at about boiling temperature before dyeing and then dyeing the thus pretreated fiber material whereby the polyor ultraphosphoric acids or their salts are added to the dye bath itself. For this purpose the polyester fiber or blends thereof are pretreated with the required amount of carrier at boiling temperature for at least 30 minutes. Without intermediate rinsing the thus pretreated fiber material is dried at C. The dye bath is then adjusted to the required pH-value, the disperse dyestuff is added, and the thus pretreated polyester fiber is dyed with the addition of the polyor ultraphosphate for one to 1% hours.

According to another modification of the process of this invention it is possible to add part of the polyor ultraphosphoric acids or their salts to the pretreatment bath containing the reduced amount of carrier and to add the remainder of the polyor ultraphosphoric acids or their salts to the dye bath. The advantage of this modification is that the toxic and undesired side effects of the carrier such as its disagreeable odor can be eliminated during the dyeing step without reducing its effectiveness.

According to a further embodiment of the present invention it is possible to completely eliminate the organic carrier by subjecting the polyester fiber to a pretreatment with boiling water for at least 30 minutes and then introducing the thus pretreated polyester fiber into a dye bath which contains between about 2 g./l. and about 5 g./l. and preferably between about 3 g./l. and about 4 g./l. of polyor ultraphosphoric acids or their salts of the above given formulas or their substitution products or mixtures thereof.

This modification of the present invention whereby no carrier is used but dyeing of the pretreated boiled polyester fiber is effected in the presence of polyor ultraphosphates is especially suitable for producing medium or light color shades.

It is also possible to subject the fiber material to a pretreatment with boiling water to which the total amount or part of the polyor ultraphosphoric acids or their salts has been added.

According to another embodiment of the present invention especially advantageous results are achieved When adding the polyor ultraphosphoric acids or their salts to the dye bath in several increments, preferably in two to three steps whereby the dyeing process is extended to more than one hour.

It is evident that the use of polyor ultraphosphoric to boiling temperature within 30 minutes. Dyeing is continued at boiling temperature for 120 minutes. Thereafter, the dyed fabric is rinsed well with cold water and is treated with a reducing bath containing, per liter; 1 cc. of ammonia solution, 2 g. of sodium hydrosulfite, and 0.5 g. of a finishing agent based on a fatty alcohol sulfate sold under the Trademark Levapon CA by Farbenfabriken Bayer AG. (siehe Lexikon Textilveredelung und Grenzgebiete by C. H. Fischer-Bobsien Ed. 1960, page 1141) at 50 C. for minutes. Thereafter, the dyed blend fabric is well rinsed with warm and cold water and dried in air.

Dyeing of the wool component of said fabric:

The thus dyed polyester-wool blend is then dyed in a boiling dye bath containing 1% of a commercial wool dyestulf of the following formula acids and their salts and substitution products produces an entirely unexpected effect which could not be arrived at from their heretofore known properties.

The process of the present invention can be used not only for the treatment of polyester fiber material but also for the treatment of mixtures of such polyester fibers with wool, cotton, and other synthetic and natural fibers. When using such polyester fiber mixtures with other fibers, i.e. when using blends of fibers, it is possible to obtain satisfactory to excellent color fastnesses in a two-bath dyeing process whereby no reductive intermediate purification of the fiber material after removal from the first dye bath is required. Blends with wool, for instance, can be dyed in a single-bath process whereby the wool is stained to a lesser degree by superficially adhering diperse dyestulf.

Conventional and well known washing and dyeing apparatus and equipment can be used to carry out the process according to the present invention. Especially advantageous washing equipment, for instance, Rotowa Centrifugal Washing Machine of the firm Haeberlein & Co. of Wattwil, Switzerland. These machines have proved of value when using highly toxic carriers.

The following examples serve to illustrate the present invention, however, without limiting the same thereto.

EXAMPLE 1 (a) A blend fabric consisting of of wool and 55% of the polyester, i.e. the condensation product of terephthalic acid and ethylene glycol is dyed in a twobath process in the following manner:

The polyester portion of the blend is dyed in the usual manner. The dye bath (soft water and a ratio of goods to liquor of 1:30) into which the polyester blend is placed is preheated to C. 2 g./l. of a chloro benzene ether-type carrier f.e. Palanil Carrier AN sold by BASF Ludwigshafen dissolved with boiling and 0.5 g./l. of dinaphthyl methane sulfonate which is used as dispersing agent are added and the dye bath is then adjusted to a pH of 5.5 by the addition of 30% acetic acid. The bath is then kept at said temperature for 15 minutes whereafter a commercial disperse dye, for instance, of the following formula OH (H) 1TIH2 I ll NHzO OH is added to yield a dyestuff concentration of 3%. After 10 minutes the temperature of the dye bath is increased of the polyester component of said blend becomes some what lighter due to the reductive intermediate rinsing and the dyeing in the Wool dye bath. The resulting color shows the following fastness properties:

Color fastness to light45 Color fastness to crocking (rubbing):

Wet rubbing-4 Dry rubbing5 Color fastness to washing (color transference test):

Staining of cotton3-4 Staining of wool3 Staining of polyester fiber34 (b) The procedure is the same as described hereinabove under (a). However, in place of 2 g./l. of the chloro benzene ether carrier, there were added only 0.2 g./l. thereof together with 1 g./l. of disodium diphosphate and the dispersing agent is completely omitted. The shade of the resulting dyed goods is darker than that obtained according to Example la. The shade of the polyester color becomes lighter only to a minor degree during dyeing of the wool component.

Color fastness to light5 Color fastness to crocking (rubbing):

Dry rubbing5 Wet rubbing-3-4 Color fastness to washing (color transference test):

Staining of cotton3-4 Staining of wool3 Staining of polyester fiber3 (c) The procedure is the same as described hereinabove under (a) whereby, however, 0.5 g./l. of the chloro benzene ether carrier and l g./l. of Graham salt are added. The depth of the color is superior to that obtained according to Examples 1a and 1b. During dyeing of the Wool component, the shade of the polyester fiber does not become substantially lighter.

Color fastness to light56 Color fastness to crocking (rubbing):

Dry rubbing-4-5 Wet rubbing-3-4 Color fastness to washing:

Staining of cotton4 Staining of wool3-4 Staining of polyester fiber4 (d) The procedure is the same as described hereinabove under 1a, 1b, and 10, whereby 0.2 g./l. of chloro benzene ether carrier and 0.5 g./l. of dinaphthyl methane sulfonate as dispersing agents are added to the dye bath. The shade of the resulting color is far inferior to that achieved according to Examples 1a, lb, and 10. Therefore, no fastness tests were carried out.

(e) The dyeing procedure is the same as described hereinabove under 1a, 1b, and 10, whereby however, no carrier is added and dyeing is effected only in the presence of 0.5 g./l. of the dispersing agent. The shade of the resulting color is still lighter than that obtained according to Example 1d. Therefore, no fastness tests were carried out.

EXAMPLE 2 The procedure is the same as disclosed hereinabove in Example 1. The blend fabric consists also of 45% of wool and 55% of polyester fiber. The blend cotains an optical brightener as it is customary in commercial dyeing plants when redyeing fabrics. Furthermore, there is investigated in this series of experiments the effect of polyphosphates in comparison to conventional carriers whereby intermediate scouring methods as they are applied in commercial operation are used. For this purpose the fabric is cut into 3 pieces or sections after dyeing the polyester fiber.

Section A is subjected to the dye bath for W001 dyeing without further intermediate scouring.

Section B is subjected to reductive scouring as described in Example 1a before the wool component is dyed.

Section C is subjected to scouring with a fatty alcohol sulfonate at a pH of 5.0 and at 70 C. For 30 minutes before the wool component is dyed.

Sections B and C are subsequently rinsed with warm and cold water after scouring whereafter the wool component is dyed.

Group I.-The polyester dye bath contains 2 g./l. of a chloro beneze ether and 0.5 g./l. of dinaphthyl methane sulfonate. The dyestuff concentration is 3%.

(A) The procedure is as described in Example la but Without intermediate scouring.

(B) The procedure is the same as described in Example 1a but with reductive intermediate scouring.

(C) The procedure is the same as described in Example la whereby intermediate scouring is effected with the addition of 1 g./l. of a fatty alcohol sulfonate detergent sold under the Trademark Dudipon 1100 come. by the firm Diersch and Schroeder Chemische Fabrik of Bremen.

Group II.The polyester dye bath contains only 2 g. of the chloro benzene ether carrier, 1 g./l. of Graham salt, and 3% of the dyestuff of the formula given in Example 1a.

(A) The procedure is the same as described in Group IA. Subsequently the wool component is dyed without intermediate scouring.

(B) The procedure is the same as described hereinabove under Group 18 but with reductive intermediate scouring before dyeing the wool component.

(C) The procedure is the same as described hereinabove under Group IC whereby 1 g./l. of the same fatty alcohol sulfonate detergent is used for scouring before the wool component is dyed.

The resulting colors confirm the results achieved on dyeing according to Example 1. The same depth of color is obtained when using 2 g./l. of Graham salt and using only 0.2 g./l. of the carrier. The color fastness of the dyed blend fabrics which contain an optical brightener, is of about the same order as that obtained according to Example 1 even when taking into consideration the variations in intermediate scouring methods.

EXAMPLE 3 Dyeing is effected according to the single-bath method. The fabric to be dyed is the same as used in Example 1 and contains about 45 of wool and 55% of polyester fiber. Both the polyester component and the wool component of the fabric are dyed at the same time. The procedure is as follows:

(a) 2 g./l. of a chloro benzene ether carrier and 0.5 g./l. of dinaphthyl methane sulfonate as dispersing agent are added to the 50 C. hot dye bath of soft water which contains the fabric to be dyed whereby the bathratio is 1:30. The pH-value of dye bath is adjusted to a pH of 5.5 by the addition of acetic acid. The fabric is treated in said bath for 30 minutes Whereafter the disperse dyestuff and the wool dyestulf as used in Example 1a are added to the bath. After 10 minutes the dye bath is heated to boiling Within 30 minutes and dyeing is effected by boiling for 2 hours. Thereafter, the dyed fabric is rinsed with cold and hot water and is scoured at 50 C. and a pH of 5.0 with the fatty alcohol sulfate detergent as used in Example 2. After rinsing with hot and cold water the fabric is dried in the air. The resulting color is of a better depth in shade than that obtained according to Example 1a, but this process of dyeing in a single bath has the disadvantage that the color fastness is not as good as when using the two-bath method:

Coior fastness to light-4-5 Color fastness to crocking (rubbing):

Dry rubbing--34 Wet rubbing2-3 Color fastness to washing with water:

Staining of cotton3 Staining of wool-3 Staining of polyester fiber3 (b) The procedure is the same as described hereinabove under (a) whereby, however, the amount of organic carrier is reduced to 0.2 g./l. 1.5 g./l. of disodium diphosphate are added.

The resulting color is weaker in depth than that obtained under (a). Its hue is somewhat more yellowish. Its color fastness properties, however, are better than those obtained when proceeding as described hereinabove under (a).

Color fastness to light6-7 Color fastness to crocking (rubbing):

Dry rubbing-34 Wet rubbing-3-4 Color fastness to washing (color transference test):

Staining of cotton3-4 Staining of wool34 Staining of polyester fiber3-4 (c) The procedure is the same as hereinabove described under (b) whereby, however, 1 g./l. of Graham salt are added in place of 1.5 g./l. disodium diphosphate. The resulting color is somewhat duller but the depth of the color is about the same as that obtained when proceeding as described hereinabove under (a) and may even be slightly superior thereto. The color fastness of the dyed fabric is also better than that of fabrics dyed according to the procedure under (a).

Color fastness to light-5-6 Color fastness to crocking (rubbing):

Dry rubbing-3-4 Wet rubbing-2 Color f)astness to washing with water (color transference tests Staining of cotton-3-4 Staining of wool-34 Staining of polyester fiber-3-4 EXAMPLE 4 (a) The procedure is the same as described hereinabove in Example la, whereby a chloro benzene ether is used as carrier and the disperse dyestuff Serilen black BRL as sold by the firm The Yorkshire, Dyeware and Chemical Co. Ltd. of Leeds, England, is added to a concentration of 4%.

The following amounts of carrier were used:

2 g./l. of the chloro benzene ether and 0.5 g./l. of dinaphthyl methane sulfonate.

4 g./l. of the chloro benzene ether and 0.5 g./l. of dinaphthyl methane sulfonate.

6 g./l. of the chloro benzene ether and 0.5 g./l. of dinaphthyl methane sulfonate.

When adding 2 g./l. of the chloro benzene ether, a dark grey color is obtained. When increasing the carrier amount to 4 g./l. up to 6 g./l., the depth of the color is increased and finally a blueish-black hue is obtained.

(b) The procedure is the same as described above under (a) whereby trichloro benzene is used as carrier and the following polyphosphates are added in the following amounts:

0.2 g./l. of trichloro benzene and 2 g./l. of an ultra hosphate with a ratio of Na O:P O of 0.98:1.0;

0.2 g./l. of trichloro benzene and 2 g./l. of disodium diphosphate;

0.5 g./l. of trichloro benzene and 1 g./l. of an ultraphosphate with a ratio of Na orP O of 0.98:1.0;

0.5 g./l. of trichloro benzene and 1 g./l. of disodium diphosphate.

The colors obtained according to Example 4a and Example 4b are compared with each other. It was found that, when using 0.2 g./l. of trichloro benzene and 2 g./l. of ultraphosphate or 0.2 g./l. of trichloro benzene and 2 g./l. of disodium diphosphate, the color was darker and pronouncedly more intense than when using 2 g./l. of carrier and proceeding according to Example 4a. The color resulting from 0.5 g./l. of trichloro benzene and 1 g./l. of ultraphosphate or, respectively, 1 g./l. of disodium diphosphate showed a considerably better depth than the color obtained with 6 g./l. of the carrier alone according to Example 4a.

The cross-sections of the fibers were microscopically examined and it was found that, when using the polyphosphates together with small amounts of carrier, the fibers were just as uniformly dyed throughout the entire crosssections as when using larger amounts of the conventional organic carriers alone.

EXAMPLE 5 This example serves to illustrate the advantages of the modification of the process according to the present invention whereby the fiber is pretreated with a reduced amount of carrier material at boiling temperature before dyeing while the polyphosphates are added to the dyeing bath itself.

(a) A polyester fabric is pretreated at boiling temperature with g./l. of trichloro benzene for 30 minutes. Thereafter, it is dyed in a dyeing bath (soft water; bath ratio: 1:30) which contains 2 g./l. of an ultraphosphate with a ratio of Na :P O of 0.98: 1.0 and 3% of a commercial disperse dyestulf Antrachinon dyestufi) of the following formula at boiling temperature and at apH of 5.0, adjusted by means of 30% acetic acid. Dyeing is completed after 1 hour. Thereafter, the fabric is rinsed with warm and cold water and dried in air. A color of a dark blue hue is obtained.

(b) To achieve the same depth in color, when using only the carrier and the same dyestuff, as it is achieved according to Example 5a, without'pretreatment according to the present invention and without the addition of a polyphosphate, 14 g./ 1. of a chloro benzene ether have to be added to the dye bath as carrier.

(0) When using trichloro benzene as carrier and otherwise proceeding as described under (b), 8 g./1. of trichloro benzene are required in order to achieve the same depth of color as obtained with a pretreatment with 4 g./l. of trichloro benzene and subsequent addition of 2 g./l. of the ultraphosphate to the dye bath.

EXAMPLE 6 (a) A polyester fabric is pretreated with 0.2 g./l. of trichloro benzene at boiling temperature whereby the bath ratio is 1:30, for 30 minutes and is subsequently dried at C. Without rinsing. The thus pretreated polyester fabric is then dyed in a dye bath (soft Water; bath ratio: 1:30) which contains 4% of the commercial disperse dyestuff of the formula given in Example 5a. The dye bath contains 0.5 g./l. of dinaphthyl methane sulfonate as dispersing agent and has been adjusted to a pH value of 5.0 by the addition of 30% acetic acid. Dyeing is completed at boiling temperature Within 1 hour. Thereafter, the dyed fabric is rinsed with cold and warm water and dried in air.

(b) A polyester fabric is subjected to the same pretreatment With trichloro benzene as described under (a) and is subsequently dyed in the same manner whereby, however, 2 g./l. of Graham salt are added, in place of dinaphthyl methane sulfonate. The color botained according to (b) is of a markedly deeper shade as that obtained according to (a).

EXAMPLE 7 (a) The procedure is the same as described in Example 6a whereby, however, 4 g./l. of a chloro benzene ether are added as carrier.

(b) The procedure is the same as described in Example 6a whereby, however, pretreatment is effected by means of 2 g./l. of a chloro benzene ether and 2 g./l. of disodium diphosphate. The pretreated fabric is dyed as described in Example 6a whereby, however, 2 g./1. of Graham salt are added, in place of dinaphthyl methane sulfonate.

The color obtained according to Example 7a which contains twice the amount of carrier as used in Example 7b is markedly lighter in shade than that obtained according to Example 7b.

EXAMPLE 8 (a) The procedure is the same as described hereinabove in Example 6a, whereby however, the amount of carrier is increased from 0.2 g./l. of trichloro benzene to 2 g./l. of said compound. The depth in color is better than that achieved according to Example 6a. This is due to the increased amount of carrier.

(b) When working under the same conditions as described under (a) and dyeing the fabric in the presence of 2 g./l. of an ultraphosphate with a ratio of Na O:P O of 0.98:1.0, in place of 'dinaphthyl methane sulfate, a color which is considerably darker than that obtained according to Example 8a.

EXAMPLE 9 (a) A polyester fabric is placed into a bath (distilled water) at a bath ratio of 1:30. The temperature is increased to 50/ C. 4 g./l. of the carrier dissolved on heating, i.e. a chloro benzene ether and 0.5 g./l. of dinaphthyl methane sulfonate are added and the bath is adjusted to a pH of 6.0 by the addition of 30% acetic acid. The fabric is treated in said bath for 15 minutes at said temperature. Thereafter 3% f acommercial disperse dyestulf of the following formula which has been dispersed in hot water before it is added to the dye bath. After 10 minutes the temperature of the bath is increased to boiling temperature. Dyeing is completed at said boiling temperature within 60 minutes. The dyed fabric is rinsed with warm and cold water and dried in air.

(b) The same polyester fabric as used in (a) is placed in a bath which contains distilled water only (bath ratio: 1:30). Thereafter, the bath is heated to boiling within 30 minutes and is kept at said boiling temperature for 30 more minutes. The polyester fabric is then dried at 100 C. in a tenter. The dried polyester fabric is placed into a dye bath heated to 50 C. which contains 2 g./l. of an ultraphosphate of a ratio Na O:P O of 0.98:1.0. 3% of the disperse dyestulf as used under (a) are added, the pH value of the dye bath is adjusted to a pH of 6.0 by the addition of acetic acid and the temperature of the bath is increased to boiling temperature within 30 minutes. At said temperature the fabric is dyed for 60 minutes, rinsed with warm and cold Water, and dried in air.

EXAMPLE The procedure is the same as described hereinabove in Example 9b whereby, however, 2.5 g./l. of Graham salt are added to the bath used for the pretreatment of the fabric. No polyphosphate is added to the dye bath. The pH value of the dye bath is also adjusted to a pH of 6.0 by the addition of acetic acid.

EXAMPLE 11 The procedure is the same as described in Example 9b whereby, however, 3.5 g./l. of disodium diphosphate are added to the pretreatment bath, in place of Graham salt.

EXAMPLE 12 The procedure is the same as described hereinabove in Example 11 whereby, however, 2 g./l. of disodium diphosphate are added to the pretreatment bath and 2 g./l. of disodium diphosphate to the dye bath.

Results.The color obtained according to Examples 9b, 10, 11, and 12 is of the same depth as the color obtained with the conventional carrier according to Example 9a.

It is, of course, understood that, in place of the dispersion dye used in the preceding examples, other disperse dyes may be employed. Such dispersion dyes are, for instance, derivatives of 1,4di-amino or 1,4,5,8-tetraamino anthraquinone and the p-amino monoazo derivatives of aromatic and heterocyclic compounds as they are described for instance, by Kirk-Othmer in Encyclopedia of Chemical Technology 2nd edition, vol. 2, pages 905- 907 and pages 506-610.

In place of the carriers used in the preceding examples, there may be employed other carriers which are absorbed onto the fiber and act as swelling agents, thus reducing attractive forces between the polymer molecules and allowing greater freedom of motion so that a faster rate of diffusion of the dyestulf through the fiber is achieved.

Other polyphosphates and ultra phosphates than those mentioned in the preceding examples may also be employed such as sodium and potassium tripolyphosphate ME P 010, Sodium and potassium tetrapolyphosphates, hexa-, heptaand higher molecular alkali polyphosphates as Kurrols potassium salt.

In the formulas given in column 2, lines 9-10,

Me indicates a metal, preferably an alkali metal, n indicates an integer from 2 to -2000 and (see, for instance, John R. van Wazer, Phosphorus and Its Compounds, Interscience Publishers, Inc., New York, N.Y., 1958, vol. I, pages 601 to 678 and 706 to 716).

Of course, many changes and variations in the dyeing procedure, the dyeing temperatures, and duration, the ratio of goods to dye bath, the pretreatment temperature and duration, the intermediate and subsequent scouring, rinsing, and drying procedures, dispersing agents, dyestuffs, and other dyeing adjuvants used, and the like may be made by those skilled in the art in accordance with the principles set forth herein and in the claims annexed hereto.

We claim:

1. In a process of dyeing goods containing polyester fibers, the steps which comprise subjecting said goods to a pretreatment with boiling Water and dyeing the thus pretreated goods in a dye bath containing a disperse dyestulf and a polyphosphoric acid compound selected from the group consisting of polyphosphoric acids, ultraphosphoric acids, their alkali metal salts, and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said dye bath.

2. The process according to claim 1, wherein the salts of the polyphosphoric acid compounds correspond to the formula wherein Me is an alkali metal, and n an integer of 2 to about 2000.

3. The process according to claim 1, wherein the salts of the polyphosphoric acid compounds correspond to the formula wherein Me is an alkali metal, and n an interger of 2 to about 2000, and xgn/ 2 and n is greater than 2 and x is greater than 1.

4. The process according to claim 1, wherein the salt of the polyphosphoric acid is sodium hexametaphosphate or disodium diphosphate.

5. The process according to claim 1, wherein the salt of the ultraphosphoric acid is a sodium ultra phosphate of a ratio Na O:P O smaller than 1.

6. The process according to claim 1, wherein the salt of the ultraphosphoric acid is a sodium ultraphosphate of a ratio Na O:P O of 0.98:1.

7. The process according to claim 1, wherein the polyphosphoric acid compound is present in the dye bath in an amount between about 3 g./l. and about 4 g./l. of said dye bath.

8. The process according to claim 1, wherein the goods are pretreated in boiling Water for at least 30 minutes.

9. The process according to claim 1, wherein the polyphosphoric acid compounds are added in increments to the dye bath during dyeing.

10. The process according to claim 1, wherein the polyphosphoric acid compounds are added in two to three increments to the dye bath during dyeing.

11. The process of claim 1 wherein the polyphosphoric acid compound is a pyrophosphate ester or a condensation product of urea and phosphorous pentoxide.

12. The process of claim 1 wherein the pH of the dye bath is about 6 to 5.

13. The process according to claim 1, wherein the goods containing polyeter fibers are subjected to a pretreatment with boiling water containing about 50% of the total amount of polyphosphoric acid compound used in the process.

14. The process according to 13, wherein the goods containing polyester fibers are subjected to a pretreatment with boiling water containing all of the polyphosphoric acid compound while the dye bath is free of said polyphosphoric acid compound.

15. Dyed textile goods containing polyester fibers of improved color fastness, said goods being dyed according to the process of claim 1.

16. In a process of dyeing goods containing polyester fibers, the steps which comprise subjecting said goods to a pretreatment with boiling water and dyeing the thus pretreated goods in a dye bath containing a disperse dyestuif and a polyphosphoric acid compound selected from the group consisting of polyphosphoric acids, ultraphosphoric acids, their alkali metal salts, and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said dye bath, and said dye bath contains a conventional carrier in an amount between about 0.2 g./l. and about 3 g./l. of said dye bath.

17. The process according to claim 16, wherein the salts of the polyphosphoric acid compounds correspond to the formula wherein Me is an alkali metal, and 11 an integer of 2 to about 2000.

18. The process according to claim 16, wherein the salts of the polyphosphoric acid compounds correspond to the formula wherein Me is an alkali metal, it an integer of 2 to about 2000, and xgn/Z.

19. The process according to claim 16, wherein the salt of the phoyphosphoric acid is sodium hexametaphosphate or disodium diphosphate.

20. The process according to claim 16, wherein the salt of the ultraphosphoric acid is a sodium ultraphosphate of a ratio Na O:P O smaller than 1.

21. The process according to claim 16, wherein the salt of the ultraphosphoric acid is a sodium ultraphosphate of a ratio Na OzP O of 0.98:1.

22. The process according to claim 16', wherein the goods are dyed, without preceding pretreatment with boiling water, in a dye bath containing the dyestuff, the polyphosphoric acid compound in an amount between about 1 g./l. and about 5 g./l. of the dye bath, and a conventional carrier in an amount between about 0.2 g./l. and about 3 g./l. of the dye bath.

23. Dyed textile goods containing polyester fibers of improved color fastness, said goods being dyed according to the process of claim 16.

24. The process which comprises pretreating a polyester fiber by subjecting it to an aqueous bath comprising a conventional carrier in an amount between about 0.2 g./l. and about 0.4 g./l. at about the boiling temperature of the bath, drying said pretreated fiber, and further treating said pretreated fiber in a dye bath comprising a disperse dyestuff and a polyphosphoric acid, an ultraphosphoric acid or their alkali metal salts, in an amount between about 1 g./l. and about 5 g./l. of said bath.

25. The process of claim 24 wherein the fiber is subjected to the boiling bath for at least 30 minutes.

26. The process of claim 24 wherein the fiber is subjected to the treatment in the dye bath for about one to one-and-a half-hours.

27. The process of claim 24 wherein the pretreatment bath comprises patr of the amount of polyphosphoric acid compound.

28. The process of claim 24 wherein the dye bath comprises all of the amount of polyphosphoric acid compound used.

29. The dyed product of claim 24.

30. A dye bath for dyeing goods containing polyester fibers, said dye bath comprising a disperse dyestufl? for said polyester fiber, and a polyphosphoric acid compound selected from the group consisting of polyphosphoric acids ultraphosphoric acids, their alkali metal salts, and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said dye bath.

31. A dye bath for dyeing goods containing polyester fibers, said dye bath comprising a disperse dyestuff for said polyester fiber, a polyphosphoric acid compound selectedfrom the group consisting of polyphosphoric acids, ultraphosphoric acids, their alkali metal salts, and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said dye bath and a conventional carrier in an amount between about 0.2 g./l. and about 3 g./l.

32. A bath for pretreating goods containing polyester fibers before dyeing said goods with dispersion dyestuffs, said pretreatment bath comprising an aqueous solution of salts of polyphosphoric acid compounds having the formula wherein Me is an alkali metal, n is an integer of 2 to about 2000, but greater than 2, and x32 but greater than 1 and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said bath.

33. A pretreatment bath for pretreating goods containing polyester fibers before dyeing said goods, said pretreatment bath comprising an aqueous solution of a polyphosphoric acid compound selected from the group consisting of polyphosphoric acids, ultraphosphoric acids, their alkali metal salts, and mixtures of said compounds in an amount between about 1 g./l. and about 5 g./l. of said bath and a conventional carrier in an amount between about 0.2 g./l. and about 3 g./l.

References Cited UNITED STATES PATENTS 2,774,647 12/1956 Mecco et a1. 8-55 X OTHER REFERENCES C. I. Munter et al., Proceedings of the A.A.T.C. & C., Jan. 28, 1935, pp. 4047. Copy in 8482 Lit.

' The Textile Manufacturer, July 1953, pp. 374-376. E. L. Caswell, Amer. Dyestuff Reporter, May 18, 1959, pp. 39, 40 and 50. Copy in 8-21 Lit.

H. U. Schmidlin, Preparation and Dyeing of Synthetic Fibers, published April 1963, by Chapman & Hall Ltd., London, pp. 2023, 255, 258, 261, 291, 292, 397, 398, 400 and 401.

DONALD LEVY, Primary Examiner T. J. HERBERT, JR., Assistant Examiner US. Cl. X.R.