US3679349A

US3679349A - Removal of polyester oligomers with chlorofluoroalkanes and methylene chloride treatment of polyester fibers

Info

Publication number: US3679349A
Application number: US107571A
Authority: US
Inventors: Hans-Ulrich Von Der Eltz; Walter Birke; Wolfgang Kunze; Franz Schon
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1970-01-20
Filing date: 1971-01-18
Publication date: 1972-07-25
Anticipated expiration: 1989-07-25
Also published as: BE761703A; FR2077227A1; CH72571A4; NL7100579A; CH555924A; DE2002285B2; FR2077227B1; DE2002285A1; GB1323994A

Abstract

PROCESS FOR THE IMPROVEMENT OF THE PROCESSING AND DYEING PROPERTIES OF TEXTILE MATERIALS CONSISTING OF OR CONTAINING HIGH MOLECULAR POLYESTERS BY TREATING THESE MATERIALS WITH A SOLVENT MIXTURE OF HALOGENATED METHANE OR ETHANE DERIVATIVES OF THE GENERAL FORMULA

R-F

IN WHICH R REPRESENTS A RADICAL OF THE FORMULA

FCL2C-CFCL-

OR CL3C-, AND METHYLENE CHLORIDE, CONTAINING BOTH THE COMPONENTS IN A WEIGHT RATIO OF FROM 30:70 TO 70:30, PREFERABLY OF FROM 45:55 TO 55:45.

Description

' United States Patent US. Cl. 8-17 7 Claims ABSTRACT OF THE DISCLOSURE Process for the improvement of the processing and dyeing properties of textile materials consisting of or containing high molecular polyesters by treating these materials with a solvent mixture of halogenated methane or ethane derivatives of the general formula in which R represents a radical of the formula or Cl C, and methylene chloride, containing both the components in a weight ratio of from 30:70 to 70:30, preferably of from 45 :55 to 55:45.

The present invention provides a process for the improvement of the processing and dyeing properties of polyester textile materials.

In a side reaction of the synthesis of polyesters, oligomers are formed which may result in certain troubles. These disturbances are caused by deposits on the fibre, which then impair the dyeability of the goods, as well as on machine parts. Besides cyclic oligomers, also linear oligomers have been detected (cf. Zeitschrift fiir die gesamte Textil-Industrie, vol. 71/7 (1969), page 488).

Generally, the portion of these oligomers in the polyester material amounts up to 5% by weight. In the course of dyeing processes, especially in the dyeing under hightemperature or thermofixation conditions these oligomers may emerge from the polymer fibre. Since oligomers cannot be dyed with the disperse dyestuffs generally used for the dyeing of polyester fibres, fair non-dyed spots may remain on the dyed goods. Moreover, dyed polyester fibres containing oligomers provoke the formation of considerable amounts of dust during the spinning process, which cause production trouble. Very often, oligomer deposits are also found in the liquor pumps of the dyeing machines resulting in interruptions of the production and further waste of time by cleaning operations.

It has therefore been tried to remove such oligomers from the polyester material by means of diiferent aftertreatments methods. For example, it is known that oligomers may partly be eliminated by means of rinsing with hot water or by an alkaline reductive after-treatment in the prescence of a tenside, for example a fatty acid polyglycol ester, and at elevated temperatures. Furthermore, it is known that oligomers may be eliminated by a treatment of the textile material with organic solvents, but this process has been of no importance in practice since it deteriorates the textile processing properties of the fibres, and, in case the material is dyed, also the dyestuff is dissolved out of the fibres in considerable amounts. Thus, the removal of oligomers for example with dioxane is known. However, after 2 hours of extraction of the "ice polyester fibre material with dioxane, only 1.5% of the oligomers are removed. This amount increases after 32 hours only and attains about 4% after 64 hours only. Methylene chloride exhibits a very good dissolving power for oligomers from high molecular polyesters; however, this causes considerable damage to the fibres resulting in a shrinkage of the fabrics. In case a dyed polyester fabric is treated with methylene chloride, besides the damage of the fibres also a considerable amount of the dyestuffs already fixed on the fibre is dissolved out.

It has now been found that the processing and dyeing properties of textile materials made from or containing high molecular polyesters can be improved in a very simple and economic manner by treating these materials with a solvent mixture of halogenated methane or ethane derivatives of the general formula in which R represents a radical of the formula -FCl CCFClor Cl C, and methylene chloride, which mixture contains both the components in a weight ratio of from 30:70 to 70:30, preferably of from 45:55 to 55:45.

In the process of the invention, an azeotropic mixture of 50.5% by weight of 1,2,2-trifiuoro-trichloro-ethane and 49.5% by weight of methylene chloride is advantageously used as solvent mixture. The boiling point of this mixture is 37 C. at 760 mm. Hg. The use of this mixture in industrial practice is specially recommended, since this azeotropic mixture behaves as uniform substance both in the liquid and in the vapor phase. Hence, there is no decrease in the amount of one of the components during the treatment and the subsequent recovery of the solvent.

The treatment with the solvent mixtures is advantageously carried out at temperatures of from about 10 to 60 0, preferably of from about 20 to 40 C. In case the treatment temperature is above the boiling point of the solvent, the treatment should be carried out in pressure-proof apparatuses under the pressure establishing itself in each special case. Furthermore, the treatment of the textile material may be also carried out with reflux of the solvent mixture.

The time of treatment necessary for the elimination of the oligomers depends above all on their amount and the temperature of the treatment medium applied. Generally, a treatment of from 1 to 15 minutes is sufiicient. However, it is also possible to continue the treatment with the solvent mixture for a longer period without damaging the textile material.

The solvent mixture is used at least in an amount necessary for the complete elimination of the oligomers from the textile material. The optimum amount to be used in each case can easily be determined in preliminary tests. Generally, a goods-to-liquor ratio of from about 1:5 to 1:50 is recommended, and it is advantageous to ensure a good circulation of the liquor.

The process of the invention may be carried out in an equipment as normally used. However, these apparatuses should be gas-proof in view of the considerable vapor pressure of the solvent mixtures already at room temperature. Thus, the process of the invention may be carried out in apparatuses as normally used for dry-cleaning. In case the polyester yarns are on cross-wound bobbins, it is possible to treat them in a normal dyeing apparatus for cross-wound bobbins; a continuous recycling of the solvent mixture, however, must be ensured in this case. The process of the invention may be carried out batchwise or continuously, the latter being especially advantageous in case the textile material is present in the form of woven or knit fabrics.

When the oligomer content in the solvent mixture is exceedingly high, the solvent mixture has to be replaced by a fresh one. This too may be determined by simple preliminary tests in each case. The treatment may also be carried out in several serial-connected baths. Another advantageous method is to heat the solvent mixture to boiling temperature, to contact the textile material wih the solvent vapors, to condense these vapors on the material and to recirculate the condensate into the boiling solvent mixture. This method is especially advantageous because the textile material is always contacted with fresh solvent mixture. The solvent mixture used is recovered by distillation and cooling, and the solvent mixture thus recovered may be used again for further treatment. Hence it is possible to work with a limited amount of solvent; smaller losses being balanced if necessary.

. As high molecular polyesters, especially polyethyleneglycol-terephthalate and modified polyethylene-glycolterephthalates are used which may also be blended with other fibrous materials, especially with cellulose fibres or wool. The textile material may be available in a variety of forms, for example flocks, combed material, yarns, woven and knit fabrics or fleeces.

The process of the invention is suitable for the treatment of both undyed and dyed or printed polyester materials. For a successful result of the process of the invention it is irrelevant whether the textile material has been dyed or printed with disperse dyestuffs, azo developing dyestuffs, vat dyestuffs or sulfuric acid esters of leuco vat dyestufis.

The solvent mixtures may also be used for the removal of oligomer deposits on textile machines.

By treating the textile material according to the process of the invention, the oligomers contained in the material are completely dissolved out. This treatment neither results in a damage of the fibre nor in the elimination of the dyestuif of dyed or printed textile materials during the treatment. The solvent treatment of the invention ensures at the same time the fixation of the fibre as up to now has been possible only by means of a corresponding heat treatment.

In comparison with the method applied up to now using aqueous media, the process of the invention is advantageous in that the treatment may be carried out at substantially lower temperatures. For this reason and on account of the substantially lower specific heat of the solvent mixtures used according to the process of the invention, the energy requirements of the process of the invention are also substantially lower than in the case of the conventional process. Further energy is economized when the textile material is dried, since the solvent mixtures used require a substantially lower evaporation heat than water. A further advantage of the process of the invention over the conventional process resides in the fact that there is caused nearly no corrosion of the equipment parts. Moreover, the process of the invention brings about no waste water problems, since the solvent mixture may be recovered in a simple manner, and the oligomer residue may easily be removed, for example by burning. This is a further advantage of the process of the invention over the conventional method.

In comparison with the known processes using organic solvents, the process of the invention provides the advantage of preventing fibre damages resulting for example in a shrinkage of the fabric. Furthermore, there is no dyestuff being dissolved out of the material by the treatment of dyed or printed textile materials. The solvent mixtures used are also considerably less toxic than the solvents used up to now. The treatment time is substantially shorter than in conventional processes, and a considerably greater amount of oligomers is eliminated than in case organic solvents are used for this purpose as this was normal up to now. A further great advantage resides in the fact that the textile materials treated according to the process of the invention need not be fixed, which means economizing considerable ener-gy amounts. I

The following examples illustrate the invention.

EXAMPLE 1 1 kg. of a dyeing produced under HT conditions on a tafetta fabric made from polyethylene-glycol-terephthalate with 2% of a disperse dyestuff of the following formula f) NH;

and showing fair spots due to deposited oligomers of the polyester material, was treated for 10 minutes at room temperature with 10 litres of an azeotropic mixture of 50.5% by weight of 1,2,Z-trifiuoro-trichloro-ethane and 49.5% by weight of methylene chloride. After this treatment, no oligomer deposits could be detected on the goods, and no dyestufl. was dissolved out of the fabric.

EXAMPLE 2 20 g. of a knit fabric made from texturized polyethyleneglycol-terephthalate fibres were dyed for minutes at 120 C. with 1.4% of a disperse dyestuff of the following 2% of a disperse dyestuff of the formula rnN 0 OH I II 1 H YP IH:

1 g./litre of a dispersing agent of the naphthalene-sulfonic acid/formaldehyde condensate type (as sodium salt) and 0.5 g./litre of a commercial carrier on the basis of an ester, at a pH of 5.5 (adjusted with acetic acid) and a goods-to-liquor ratio of 1:20. After rinsing and drying, half of the dyed fabric was treated for 15 minutes at room temperature in ml. of methylene chloride, the other half was treated under the same conditions in a mixture of 45 ml. of 1,2,Z-trifluoro-trichoro-ethane and 55 ml. of methylene chloride. Subsequently, both pieces were dried 1n air.

The dyed fabric treated only with methylene chloride showed very deep creases, and in this case a very heavy bleeding of the dyestuffs off the dyeing into the treatment bath was observed. The fabric treated with the above mixture was completely smooth, and no bleeding into the bath could be observed; oligomers could neither be detected any more.

EXAMPLE 3 The warp and weft of two non-fixed taffeta fabrics made from polyethylene-glycol terephthalate fibres (size about 30 x 30 cm. each) were marked in intervals of about 20 cm. Subsequently, the fabric was treated as follows:

(a) immersed for 15 minutes at room temperature in methylene chloride; goods-to-liquor ratio 1:20,

(b) immersed for 15 minutes at room temperature in a mixture of 50% of methylene chloride and 50% of 1,2,2 trifluorotrichloro-ethane; goods-to-liquor ratio 1:20.

After this treatment, both of the fabrics were dried in air. After drying, it could be observed that the fabric treated only with methylene chloride was very heavily creased, while the other fabric was completely smooth. When measuring the intervals marked, the following shrinkage values resulted:

fabric (a): 4.8% and 5% shrinkage of the warp and the weft respectively, fabric (b): no shrinkage.

used.

EXAMPLE 4 20 g. of a knit fabric made from texturized polyethylene-glycol-terephthalate fibres were dyed for 90 minutes at 125 C. with 0.9% of a disperse dyestutf of the formula 0.4% of a dyestulf of the formula HrN (HI and 1.2% of a dyestulf of the formula 11 11,0 o,N--N= @mcmomom at a liquor ratio of 1:30. The pH of the bath was adjusted to 5.1 by means of acetic acid.

After rinsing and drying, half of the dyeing was treated for 15 minutes at room temperature with 100 ml. of methylene chloride, the other half, under the same conditions, with a mixture of 50 ml. of fiuoro-trichloro-methane and 50 ml. of methylene chloride. Subsequently, both pieces were dried in air.

It was observed that the dyed fabric treated only with methylene chloride was very heavily creased and that there was also bleeding of the dyestuffs off the dyeing into the solvent, i.e. dissolution of the dyestuffs in the solvent, so that the solvent was coloured to a great extent. In the other case, where the fluoro-trichloro-methane/methylene chloride mixture was used, a completely smooth fabric was obtained and the solvent mixture was not coloured. No oligomer deposits on the fabric could be detected after the treatment.

We claim:

1. A process for the improvement of the processing and dyeing of polyester textiles which comprises applying to these textiles a solvent mixture of halogenated methane or ethane derivatives of the general formula in which R represents a radical of the formula FCbC- CFCl-- or Cl C, and methylene chloride, containing both the components in a weight ratio of from 30:70 to :30.

2. A process as claimed in claim 1, which comprises using a solvent mixture containing both the components in a weight ratio of from 45:55 to 55:45.

3. A process as claimed in claim 1, which comprises using as solvent mixture an azeotropic mixture of 50.5% by weight of 1,2,2--trifluoro-trichloro-ethane and 49.5% by weight of methylene chloride.

4. A process as claimed in claim 1, which comprises carrying out the treatment at temperatures of from about 10 to 60 C.

5. A process as claimed in claim 4, which comprises carrying out the treatment at temperatures of from 20 to 40 C.

6. A process as claimed in claim 1, which comprises treating textile materials made from polyethylene-glycolterephthalates or their mixtures with cellulose fibres or wool.

7. A process as claimed in claim 1, which comprises treating textile materials dyed or printed with disperse dyestuffs with the solvent mixture of claim 1.

References Cited UNITED STATES PATENTS 3,129,053 4/ 1964 Castle 8130.1 2,981,978 5/ 1961 Grifling 8Dig. 4 3,199,679 10/ 1965 Sayler 8142 DONALD LEVY, Primary Examiner U.S. Cl. X.R.