Process For The Dyeings Of Blends Of Spandex Fibers And Polyamide Fibers

Abstract

Process for dyeing blends of spandex and polyamide fiber materials in which the blended material is first pretreated with an agent for retarding drawing of the dyestuff on to the polyamide fiber portion in the blend; the thus pretreated material is then entered into another bath containing the dyestuff and an organic compound, which is a solvent for the dyestuff, or the dyestuff and the last-mentioned organic compound are added to the bath in which the pretreatment with retarder has taken place, whereupon the bath and goods therein are treated in a first stage to a temperature of from about 40.degree. up to 70.degree. C. for about 40 to 60 minutes and then at a temperature above 80.degree. C., and preferably between 90.degree. and 95.degree. C., i.e., below the boiling point of the bath for approximately another 30 minutes to 2 hours.

Description

DETAILED DISCLOSURE

The invention relates to the dyeing of blended fiber materials made from both spandex-type elastomeric fibers and polyamide fibers.

Where hydrophilic acid dyes are used in the dyeing of fabrics comprising spandex-type elastomeric polyamide blends of fibers there is the disadvantage that these dyes normally partition strongly in favour of the polyamide fibers.

As a result, the depth of shade in which the spandex-type fibers in the blend are dyed is greatly inferior to that of the polyamide fibers in the blend.

Dyes of low hydrophilic character, for example those with none or a low degree of sulphonation, partition more satisfactorily by normal dyeing methods but such dyes have other deficiencies. For instance, disperse dyes have poor wet fastness and some acid and premetallized dyes have poor solubility under low liquor ratio dyeing conditions and generally give stripey dyeings or dyeings of poor solidity on such cloths, especially under jig dyeing conditions.

It is, therefore, an object of this invention to provide a process for the dyeing of blends of fabrics comprising spandex-type and polyamide fibers and by means of hydrophilic dyes, which allows the dyeing of both types of fibers present in the blend in practically uniform depths of shade. This object is attained by the process according to the invention which comprises

A. PRETREATING BLENDED FIBER MATERIAL COMPRISING SPANDEX-TYPE ELASTOMERIC FIBERS AND POLYAMIDE FIBERS WITH AN ANIONIC BLOCKING AGENT AT AN ELEVATED TEMPERATURE CAPABLE OF RETARDING THE DRAWING OF HYDROPHILIC DYES ON TO POLYAMIDE FIBERS;

B. CONTACTING THE THUS PRETREATED FIBER MATERIAL IN AN AQUEOUS MEDIUM WITH HYDROPHILIC DYE AND WITH AN ORGANIC COMPOUND OF THE TYPE DESCRIBED IN British Pat. No. 856,381, which compound is a solvent for the dye, is liquid under the conditions of dyeing and insoluble or only slightly soluble in water, and in which compound the solubility of the dye is greater than in water; and

C. HEATING THE AQUEOUS MEDIUM CONTAINING THE BLENDED FIBER MATERIAL PRETREATED WITH RETARDER, THE DYE AND THE AFORESAID ORGANIC COMPOUND, AT A TEMPERATURE IN THE RANGE ABOVE ROOM TEMPERATURE UP TO 70.degree. C., and preferably at about 40.degree. to 60.degree. C., preferably for a sufficient time to allow the maximum amount of dye to draw on the fibers as will exhaust from the dye-bath at this temperature, this maximum exhaustion taking place usually within about 20 to 60, and optimally in about 40 to 60 minutes; and

d. heating the bath containing the goods, dye and aforesaid organic compound further at a higher temperature, in the range of from 70.degree. C. to the boiling point of the dyebath, in practice between 80.degree. and 100.degree., and optimally between 90.degree. and 95.degree. C., for a period ranging from about 30 minutes to 2 hours, and more preferably for about 1 hour.

These fiber blends are dyed unexpectedly in uniform depths of shade, while, if the dyebath and goods described under (b), supra, are heated in a single heating stage, e.g. at a temperature of 60.degree., or of 90.degree., the polyamide fibers in the blend are dyed in a much deeper shade than the spandex-type fibers. As spandex-type elastomeric fibers, particularly elastomeric polyurethane fibers are used, e.g. those marketed under the tradename of Lycra. As polyamide fibers, nylon fibers, e.g. those of nylon 6 and 6.6 are present in the blended fabrics to be dyed by the process of the invention.

The said fiber blends to be dyed according to the invention can be in any blending ratio and form desired, e.g. in the form of yarns, fabrics and the like. The process according to the invention is particularly suitable for the dyeing of fabrics consisting of elastomeric polyurethane fibers coated with nylon 6 or nylon 6.6 and of fabrics having stretch properties, such as fabrics used for women's foundation garments and swimming costumes.

The pretreatment with the anionic blocking agent may be carried out by any conventional method. For instance, the blended fabric may be placed in a bath containing the blocking agent or the fabric may be padded through a concentrated solution of the anionic blocking agent.

The blocking agent may be an anionic compound which is capable of being exhausted on to nylon occupying amino groups or dye sites, but which is substantially colourless. Examples of anionic blocking agents which may be used in this process are organic sulphonic acids, such as di-isobutyl naphthalene sulphonate (Irgasol NJ), naphthalene sulphonic acid formaldehyde condensate (Irgasol DA), sulphonated ricinoleic acid (Tinegal BAN) or 4,4'-dichloro-2'-(3", 4"-dichlorophenylureido)-di-phenylether-2-sulphonic acid. The proportion of anionic blocking agent used may be in the range of 0.1 to 5 percent by weight based on the weight of the fibers and is preferably about 2 percent. The pretreatment is most efficiently carried out at a temperature between 70.degree. and 100.degree. C. for a period of 15 to 30 minutes. Longer period of time, however, may conveniently be used.

After the pretreatment the dyeing is commenced preferably in a fresh bath, in the presence of the color, organic compound and, if necessary an acid or acid-salt to adjust the pH of the dye in order to achieve exhaustion on to the fiber.

The proportion of the dye used in the process may be in a wide range but the quantity used is governed by the shade requirements of the dyeing to be obtained.

The choice of the organic compound will depend on the particular dye used and the nature of the fibers to be dyed. If the organic compound is insoluble in water, or so slightly soluble that some of it remains undissolved, it is preferably to use an aqueous emulsion of the organic compound. Any emulsifying agent used for forming the aqueous emulsion should not, of course, retard dye absorption. Dyeing can be effected satisfactorily, however, without emulsification of the organic compound if a solvent miscible with both the organic compound and water is present in the dyebath. Examples of suitable organic compounds which may be used in the process of the present invention include higher alkanols having at least four carbon atoms, e.g. n-butyl alcohol, amyl alcohol and n-hexyl alcohol, cyclohexanol, Alphanol (a proprietary mixture of aliphatic alcohols), Nonanol (a proprietary mixture of aliphatic alcohols), Geraniol, Citronellol, Benzyl alcohol, Thymol (3-methyl-6-isopropylphenol), Carvacrol (isopropyl cresol), amyl lactate, dibutyl phthalate, n-butyl acetate, benzaldehyde, acetophenone and toluene. Benzyl alcohol has been found to be particularly useful.

The amount of organic compound which should be present during the dyeing in an amount of at least about 0.5 percent varies according to the particular organic compound used, the nature of the dyestuff, its concentration in the composition and the temperature to be used. It should be present in sufficient amount to achieve uniform depth of shade on both the spandex-type and the polyamide fibers of the blended fabric. This is usually the case if the organic compound is present in the amount of at least about 0.5 percent calculated on the weight of the dyebath. It may be present up to the maximum amount in water and where benzyl alcohol is used, it is preferably about 2 to 4 percent, calculated on the total weight of the dyebath.

The dye liquor can contain further auxiliaries usual in the textile industry, particularly acids or acid salts, such as organic acids or their salts and also inorganic acids or their salts. Examples of these compounds are acetic acid, ammonium acetate, sulphuric acid, ammonium sulphate and ethyl lactate. The acid or acid-salt used may be in a quantity conventionally used in the dyeing of nylon but is preferably a solution having a concentration in the range of 0.01 to 1 percent.

Surprisingly, in the process according to the invention, the dyestuffs draw so well on e.g. the polyurethane part of spandex-type fibers in the blended material that well penetrated dyeings of uniform depth of shade on both the spandex-type and the polyamide fibers are obtained.

The function played by the aforesaid organic compound in the dyeing process of the invention is not very well understood at the present. It could have been expected from the use made thereof in British Pat. No. 856,381 that the depth of shade on the blended fibers would be generally increased thereby, but not with such change in the ratio of partition that dyeings of uniform depth are obtained.

It should also be noted that successful dyeing of the blended fibers in uniform depth requires carrying out the treatment of the goods in the dyebath successively in the two above-described temperature ranges.

The process is suitable for any type of textile dyeing machine but is particularly suitable for the jig and also the beam.

The following non-limitative examples further illustrate the present invention.

EXAMPLE 1

200 g. of fabric consisting of a blend of elastomeric polyurethane (e.g. Lycra) fiber and nylon 6.6 fibers are pre-treated for 30 minutes at 90.degree.-95.degree. C., with 4 g. of di-isobutyl naphthalene sulfonate in the presence of 0.5 ml. of 40 percent acetic acid in 1,000 ml. of water.

The blended fabric is then transferred to a fresh bath containing 2 g of the dyestuff of the formula ##SPC1##

(Acid Blue 113, Color Index No. 26360),

0.5 ml of 40 percent acetic acid and 40 ml. of benzyl alcohol in 1,000 ml. of water and heated therein for 20 minutes at 40.degree. C. and 40 minutes at 50.degree. C. The temperature of the dye bath is then raised to 90.degree.-95.degree. C. and maintained at this level for 1 hour.

A fabric is obtained in which the polyurethane and polyamide fibers are dyed in a blue shade of uniform depth.

The weight ratio of Lycra to nylon 6.6 fibers in the blended fabric used in Example 1 and all subsequent examples is 1:1. Similar results are obtained in which this ratio is 3:1, 3:2, 1:2 or 1:3, or in which the nylon 6.6 fibers are replaced by nylon 6 fibers.

EXAMPLE 2

200 g. of fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated for 30 minutes at 90.degree.-95.degree. C. with 4 g. of di-isobutyl naphthalene sulfonate in the presence of 0.5 ml of 40 percent acetic acid in 1,000 ml. of water.

The blended fabric is then dyed in a fresh bath containing 4 g. of acid navy blue dye, the major portion of which consists of Acid Blue 113, 0.5 ml of 40 percent acetic acid, and 40 ml. of benzyl alcohol in 1,000 ml. of water for 20 minutes at 40.degree. C., and 40 minutes at 50.degree. C. The temperature of the dye bath is then raised to 90.degree.-95.degree. C. and maintained at this level for 1 hour.

A fabric dyed in a deep blue shade of uniform depth is obtained.

A fabric of blue shade and similar substantially uniform depth is obtained by repeating Example 2, but using therein 4 g. of the dyestuff of the formula ##SPC2##

EXAMPLE 3

200 g. of fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated for 30 minutes at 90.degree.-95.degree. C. with 4 g. of di-isobutyl naphthalene sulfonate in the presence of 0.5 ml. of 40 percent acetic acid in 1,000 ml. of water.

The blended fabric is then dyed in a fresh bath containing 10 g. of the dye which is a mixture in a weight ratio of about 1:1 of the 1:1 and 1:2 chromium complexes of the dye-stuff of the formula ##SPC3##

(Acid Black 52, Color Index No. 15711),

0.25 ml of 40 percent acetic acid and 40 ml. of benzyl alcohol in 1,000 ml. of water for 20 minutes at 40.degree. C., and 40 minutes at 50.degree. C. The temperature of the dye bath is subsequently raised to 90.degree.-95.degree. C. and maintained for 1 hour.

A blended fabric dyed black in uniform depth of shade is obtained.

EXAMPLE 4

200 g. of a fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated for 30 minuted at 90.degree.-95.degree. C. with 0.2 g of 4,4'-dichloro-2'-(3", 4"-dichlorophenylureido)-diphenylether-2-sulfonic acid in the presence of 0.5 ml. of 40 percent acetic acid in 1,000 ml. of water.

The blended fabric is then dyed in a fresh bath containing 3 g. of the same dyestuff as is employed in Example 1, 0.5 ml. of 40 percent acetic acid, and 40 ml. of benzyl alcohol in 1,000 ml. of water for 1 hour at 50.degree. C. The temperature of the dye bath is subsequently raised to 90.degree.-95.degree. C. and maintained for 1 hour.

The fabric is thereby dyed in a blue shade of very satisfactory uniformity of depth.

Similarly, a fabric dyed in red shade of very uniform depth is obtained by repeating Example 4, but using therein as dye 3 g. of the dyestuff of the formula ##SPC4##

By repeating the procedure described in the above Example but using 20 ml. of benzyl alcohol instead of 40 ml. a red dyeing on the blended fabric is obtained, in which the polyurethane and the nylon fibers are both dyed the same depth of shade.

EXAMPLE 5

200 g. of fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated for 30 minutes at 90.degree.-95.degree. C, with 10 g. of a condensation product from naphthalene-2-sulfonic acid and formaldehyde in the presence of 0.5 ml of 40 percent acetic acid in 1,000 ml of water.

The fabric is then dyed in a fresh bath containing 3 g. of a dyestuff used in Example 1, 0.5 ml of 40 percent acetic acid, and 40 ml. of benzyl alcohol in 1,000 ml. of water for one hour at 50.degree. C. The temperature of the dye bath is subsequently raised to 90.degree.-95.degree. C. and maintained for 1 hour.

A fabric dyed in blue shade is obtained in which the polyurethane and the nylon fibers are dyed with the same depth of shade.

A fabric in which the polyurethane and the nylon fibers are both dyed orange in practically the same depth of shade is obtained by repeating Example 5, but using as dye therein 3 g. of the dyestuff of the formula ##SPC5##

By repeating the procedure described in the above Example but using instead of 40 ml. only 20 ml. of benzyl alcohol, an equally uniform orange dyeing on said blended fabric is obtained.

EXAMPLE 6

200 g. of a fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated for 30 minutes at 90.degree.-95.degree. C. with 2 g of sulfonated ricinoleic acid in the presence of 0.5 ml. of 40 percent acetic acid in 1,000 ml. of water.

The pretreated fabric is then dyed in a fresh bath containing 3 g. of the dyestuff used in Example 1 in the presence of 0.5 ml of 40 percent acetic acid and 40 ml. of benzyl alcohol in 1,000 ml. of water for 1 hour at 50.degree. C. The temperature of the dye bath is then raised to 90.degree.-95.degree. C. and maintained at this level for 1 hour.

A fabric dyed blue is obtained in which both the polyurethane and the nylon fibers are dyed in the same depth of shade.

By repeating the procedure described in the above Example but raising the temperature of the dye bath to 80.degree. C. only instead of 90.degree.-95.degree. C., an equally uniform blue dyeing on said blended fabric is obtained.

COMPARATIVE EXAMPLE

200 g. of a fabric consisting of a blend of Lycra and nylon 6.6 fibers are pretreated at 95.degree. C. and dyed as in Example 1 but in the absence of benzyl alcohol, a fabric is obtained in which the depth of shade of the polyurethane fibers is very inferior to that of the nylon fibers.

When 200 g. of a fabric consisting of a blend of Lycra and nylon 6.6 fibers are dyed as in Example 1 but without any pretreatment a fabric is obtained in which there is no uniformity of depth in the shade of the polyurethane and the nylon fibers.

Neither is such uniformity of depth of shade attained, if Example 1 is repeated, but the temperature of the dyebath is maintained during the entire dyeing treatment below 70.degree. C. only, or if that temperature is maintained from the beginning above 70.degree. C.

Similar dyeings of uniform depth of shade are obtained by repeating Examples 1 to 6, but using therein in lieu of benzyl alcohol an equimolar amount of one of the following organic compounds:

n-butanol

amyl alcohol

n-hexanol

cyclohexanol

geraniol

citronellol

thymol

carvacrol

amyl lactate

dibutyl phthalate

n-butyl acetate

benzaldehyde

acetophenone

toluene.

Claims

We claim:

1. A process for the dyeing of blends of spandex elastomeric fibers and polyamide fibers, comprising

a. pretreating blended goods comprising said fibers with an organic sulfonic acid as anionic blocking agent, at a temperature of from 70.degree. to 100.degree. C., and

b. dyeing the pretreated goods in an aqueous medium containing a water-soluble anionic dye and an organic compound which is a solvent for said dye and is selected from the group consisting of higher alkanols having at least 4 carbon atoms, cyclohexanol, geraniol, citronellol, 3-methyl-6-isopropylphenol, isopropyl cresol, benzyl alcohol, amyl lactate, dibutyl phthalate, n-butyl acetate, benzaldehyde, acetophenone and toluene, the dyeing being carried out by

i. heating the whole at a temperature above room temperature but below 70.degree. C. for at least 20 minutes, and then

ii. heating the whole at a temperature of from 70.degree. C. to the boiling point of the aqueous medium until completion of the dyeing,

the organic compound being present in the aqueous medium in an amount sufficient to achieve, at completion of the dyeing, a substantially uniform depth of shade on both the spandex-type fibers and the polyamide fibers.

2. A process as defined in claim 1, wherein dyeing step (b) is carried out in a fresh bath.

3. A process as defined in claim 1, wherein said spandex fibers are elastomeric polyurethane fibers and said polyamide fibers are nylon fibers.

4. A process as defined in claim 1, wherein said anionic blocking agent is used in an amount of from about 0.1 to 5 percent of the total dry weight of the fibers and the pretreatment therewith is carried out for a period of from about 15 to 30 minutes.

5. A process as defined in claim 1, wherein step (c) is carried out at a temperature of from 40.degree. to 60.degree. C. for about 20 to 60 minutes.

6. A process as defined in claim 1, wherein said organic compound is benzyl alcohol.

7. A process as defined in claim 1, wherein step (d) is carried out at a temperature in the range of from 80.degree. to 100.degree. C. for a time of from 30 minutes to 2 hours.

8. A process as defined in claim 7, wherein step (d) is carried out at a temperature of from 90.degree. to 95.degree. C.

9. A fabric consisting essentially of a blend comprising spandex elastomeric fibers and polyamide fibers in which both said types of fibers are dyed in substantially uniform shade by a process as described in claim 1.