AU661581B2 - Process for the dyeing of yarns - Google Patents

Description

661581 Our Ref: 471757 P/00/ 011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL.

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Address for Service: Invention Title: Bayer Aktiengesellschaft D-5090 Leverkusen Bayerwerk

GERMANY

DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10) Barrack Street SYDNEY NSVI 2000 Process for the dyeing of yarns The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 The invention relates to a process for the dyeing of yarns made of natural wool, other animal hairs, silk or blends thereof with other native and/or synthetic fibres, characterised in that the yarn is exposed to dye liquor in a dyeing apparatus and that the yam used is in the form of a cylindrical package having a package density of 160 to 280 g/l and further characterised in that a differential pressure of 0.05-05 bar, preferably 0.08-0.3 bar, particularly preferably 0.1-0.3 bar is applied to the liquor, which pressure exceeds the loss in pressure caused by the dyeing apparatus and yarn.

The package density is preferably set at 180 to 280 g/l, particularly preferably at 210 to 260 g/l, very particularly preferably at 210 to 250 g/l. The advantages of the process according to the invention are obtained when using essentially cylindrical packages (centres and wound yarn). Conical, convex or concave packages are less suitable. However, centres usable according to the invention may contain, possibly only at the ends or on 15 the inner surface, conical formations in such a manner that they can be connected axially in the usual manner.

The yarn to be dyed is likewise wound cylindrically on such an essentially cylindrical centre.

S"Examples of yarns which are suitable for the dyeing process according to the invention in such a wound form are carpet yarns, machine-knitting yarns, hand-knitting yarns and yarns for producing other textile fabrics.

Preferably, the process according to the invention relates to the dyeing of carpet yarn and hand-knitting 25 yarn in which a particularly high degree of uniformity in penetration of dye and in conservation of the yarn bulk -1is demanded. Both of these demands must be fulfilled between the inner and outer region of the package.

Package densities are dependent on the yarn thickness which is expressed in Nm (metric count). This designation is a measure of the length/weight ratio. Nm 100 corresponds to 100 m of yarn per g.

The substrates to be dyed according to the invention are wool, other animal hairs, such as angora wool or cashmere wool, silk or blends thereof with other native and/or synthetic fibres, such as with polyester, cellulose (CEL) or polyamide furthermore polyamide and polyacrylonitrile (PAC). Preferably, wool, other animal hairs, polyacrylonitrile and blends thereof with other fibres may be mentioned.

Substrates of this type have hitherto been dyed by the hank dyeing method because advantageously the resulting change in structure (loss in bulk) was slight and, at the same time, the required uniformity in the distributicn of dye was achieved. The disadvantage of this hank dyeing 20 method is the cost-intensive handling which, on the one hand, consisted in a cumbersome handling of the hanks and in the expensive production of the hanks, which are only required for the dyeing process; the reason for this is that the yam must be taken off a bobbin and rewound in hank form which, i 25 after dyeing, must then be wound again on a bobbin for further use, since, for further use of yams, only a bobbin can be passed co oeee *c*o* *eeoo e Le A 28 537 2 onto the automated processing steps. Furthermore, hank dyeing is usually carried out in a long liquor ratio.

Although, as already discussed, acceptable levelness of the dyeing was achieved, improved levelness was desired, since, in the case of higher fastness requirements, the levelness obtained with the dyestuffs usually used nowadays (for example levelling dyestuffs and 1:2 metal complex dyestuffs in combination with milling dyestuffs) was not yet satisfactory. The process according to the invention fulfils these requirements while conserving the yarn bulk customary for dyeing in hank form.

Despite its disadvantages, the hank dyeing method described is still being carried out, since the dyeing of yarns in package form has given poorer results. Currently, the bobbins used for carrying out the automated processing steps have a package density of about 300 g/l to around 500 g/l. The dyeing of yarns, especially carpet yarns, on packages wound in this manner results in non-uniformities in the hue and in the yarn, which are not accepted by the consumer in the finished carpet or knitted fabric. On the other hand, package densities of less than 300 g/l give only a small space/time yield and would be expected during further processing to lead to excessively low stability in handling, and during dyeing to lead to 25 channelling in combination with non-uniformity of the dyeing and of the bulk resulting therefrom. It is surprising that, contrary to this expectation, excellent uniformity of the dyeing and completely satisfactory further processing to give the end product are possible.

eeo 9 Le A 28 537 3 Usable package centres include any customary ones known to those skilled in the art. Such centers are perforated, enabling the dye liquor to be pumped from the outside through the yarn to the inside or from the inside through the yarn to the outside or periodically in either direction by reversal. Advantageously, the pumping direction is from the inside through the yarn to the outside. In this way, yarn strain due to deformation is particularly low.

Apparatus geometry, pipework and valves give rise to a loss in pressure. In addition to this loss in pressure, friction between the material to be dyed and the dye liquor generates a differential pressure which is registered by a manometer. The resulting differential pressure of the dye liquor is 0.05 to 0.5 bar, preferably 0.08 to 0.3 bar, particularly preferably 0.1 to 0.3 bar. Any differential pressure exceeding that given by the apparatus is applied according to the invention.

The recirculated dye liquor has a volume of 10-35 litres .20 per minute per kg of yarn, preferably 10 to 30 1/min/kg, particulary preferably 12 to 30 1/min/kg, very particularly preferably 15 to 30 1/min/kg.

0: The final dyeing temperature to be set according to the invention is 70 120 0 C, preferably 75-110 0 C at 25 atmospheric pressure or slight excess atmospheric pressure. Particularly preferably, dyeing can be carried out below the boiling temperature and in that case at atmospheric .00.

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Le A 28 537 4 pressure, for example at 80 89 0 C, in many cases at to A comparison of the costs of a lot of carpet yarn to be dyed in hank form with those of a lot to be dyed in package form gives the following cost structure for the manufacture of the two forms of make-up, their dyeing, and the processes carried out before and after dyeing: The hitherto customary dyeing of carpet yarn in hank form requires the following manufacturing steps: General: The yarn is delivered by the spinning mill in the form of bobbins and must be rewound into hanks which, after dyeing, again must be rewound in the form of bobbins (creel bobbins) for further processing. Compared with 15 rewinding from the bobbins of the spinning machine to the S dyeing packages and then to the creel bobbins, including the resulting waste, these process steps involve about twice the expense.

Prewash: i.

20 In the case of hanks, the wash which precedes dyeing can only be carried out on a hank washing machine at high labour and energy costs. In the case of packages, this prewash can be taken care of on a dyeing machine at an expense of only about 25% (compared with the hank washing Le A 28 537

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Le A28 537 -5 machine).

Dyeing: There are also distinct differences between hank and package dyeing even in the actual dyeing with respect to the classes of dyestuff.

In hank dyeing, predominantly acid levelling dyestuffs and also 1:2 metal complex dyestuffs (MCDs) without free sulpho groups, occasionally in combination with milling O dyestuffs, are used.

In contrast, in package dyeing, 1:2 MCDs having one sulpho group in combination with milling dyestuffs are sufficient for all hues. Such a dyestuff selection covers all fastness requirements, which cannot always be ensured in the case of acid levelling dyestuffs.

15 1:2 MCDs having one sulpho group are about 20-30% less expensive than 1:2 MCDs without a free sulpho group.

The smaller stock of dyestuffs results in further substantial cost advantages.

.:0 The machines customary in the dyeing of carpet yarn in hank form are only equipped with one yarn carrier which has to be unloaded and loaded in succession. This results in relatively long machine down-times.

Le A 28 537 6 Package dyeing machines are usually equipped with two yarn carriers, thus significantly reducing the machine dcwn-time. During the dyeing process, the second carrier can be unloaded and reloaded.

Dyeing profile: Even when the selection of dyestuffs mentioned under "Dyeing" is used, the hank dyeing machines, which are often very big and contain up to about 2 tonnes of yarn, often give only insufficient levelness of the dyeing, 10 despite dye liquor heating rates of only 0.5-1 0 C/min.

If the same yarns are dyed in the form of packages, no problems are encountered with respect to levelness of the dyeing, even at dye liquor heating rates of up to 2°C/min; this results in a substantial saving of time.

15 Hydroextraction and drying Hydroextraction and drying of hank-dyed material is very time-consuming and cost-intensive, since each hank has to be handled individually. In most cases, drying is carried out in cabinet dryers, the drying capacity of which is 20 less than that of today's types of dryer for packages.

The package-dyed material is easier to handle and allows a more rapid material transport which, in contrast to hank yarns, can additionally be automated by the use of robots and thus further accelerated.

Le A 28 537 7 Example 1 Carpet yarn (wool), for example an Nmll/2, was introduced, in a package dyeing apparatus at a liquor ratio of 10:1, into a hot bath at 45 0 C containing, per litre, 0.2 g of the dyestuff Acid Yellow 232 0.2 g of the dyestuff Acid Red 414 0.2 g of the dyestuff Acid Black 220 1 g of calc. sodium sulphate 3 g of 60% strength acetic acid pH 4.5-5) 0.5 g of an alkylaryl-polyglycol ether condensation Sproduct (condensation product of i-nonylphenol, hexamethylenediamine and formaldehyde with 60 mol of EO and of a tallow fatty amine with 20 mol of

EO)

1 g of nonylphenol-polyglycol ether with 7 mol of EO The bath was then heated to 85-90"C over a period of 45 min., and dyeing was continued for another 30-45 min.

The package density was 220 g/l.

This gave a beige dyeing whose levelness is so good that 20 it can be processed without problems into a solid-shade velour carpet. Owing to the package density mentioned, yarn deformation between the inner and outer layers of the package is so low that no contrasts in shade whatsoever become visible in the carpet surface. Such a 25 dyeing recipe has hitherto been avoided in the dyeing of hank yarns because of the high risk of unlevelness. As is known, the dyestuffs used in hank dyeing have better Le A 28 537 8 levelling properties but a lower fastness level. And a liquor ratio of 10:1 is not possible in hank dyeing for technical reasons.

A comparable result was obtained by carrying out a dyeing at 98 0 C, using 1 g (instead of 0.5 g) of the alkylarylpolyglycol ether condensation product; the use of nonylphenol-polyglycol ether with 7 mol of EO was not necessary.

Example 2 Carpet yarn consisting of 80% of wool and 20% of nylon 6.6 and having a yarn count of Nm 6 was introduced, in a package dyeing apparatus at a liquor ratio of 10:1, into a hot bath at 45 0 C containing, per litre, 0.05 g of Acid Yellow 155 200% gran.

0.05 g of Acid Red 279 150% gran.

0.05 g of Acid Black 240 200% gran.

S1 g of ammonium sulphate 1.5 g of a condensation product of diphenyl sulphone and phenolsulphonic acid with formaldehyde 20 1 g of nonylphenol polyglycol ether with 7 mol of EO.

The package density was 240 g/l.

The bath was then heated to 85-90*C over a period of min., and after another 30-40 min. dyeing was complete.

Le A 28 537 9 Such a dyeing recipe could also be dyed by modern hank dyeing methods, but only at a significant higher liquor ratio of 25:1 or higher.

Example 3 Hand-knitting yarn made of wool and having a package density of 220 g/l was introduced, in a package dyeing apparatus at a liquor ratio of 10:1, into a hot bath at containing, per litre 1 g 6f Mordant Red 3 1 g of calc. sodium sulphate 3 g of 60% strength acetic acid pH 0.3 g of a condensation product of isononylphenol, hexamethylenediamine and formaldehyde with 60 mol of EO and of a tallow fatty amine with 20 mol of

EO

1 g of nonylphenol with 7 mol of EO.

oe The dyebath was then heated to 85°C over 'a period of min. Dyeing was carried out at this temperature for 30 40 min. For substantial exhaustion of the dye :20 liquor, 1% of 85% strength formic acid was then added.

Chroming was then carried out in a fresh bath at pH 4 and i. 90°C over a period of 30 min. using formic acid.

The dyeing was completed in the usual manner, giving a red dyeing whose depth of shade, fastness properties and yarn bulk correspond to a dyeing in hank form at 98C.

Le A 28 537 10 Example 4 Machine-knitting yarn for WO/PAC of composition 70:30 was introduced, in a package dyeing apparatus at a liquor ratio of 10:1, into a hot bath at 45 0 C containing, per litre, 0.09 g of Basic Yellow 028 0.018 g of Basic Red 018 0.062 g of Basic Blue mix 0.165 c of Acid Yellow 61 0.044 g of Acid Red 118 S0.089 g of Acid blue 82 1 g of calc. sodium sulphate 3 g of 60% strength acetic acid pH 1 g of oleyl alcohol with 56 mol of EO.

The dyebath was then heated to 98'C over a period of min. The dyeing was carried out at this temperature i for 45 min. Dyeing was then completed in the usual manner. The package density was 260 g/l. The quality of the dyeing corresponded to that of a hank dyeing.

20 Example Machine-knitting yarn made of PAC was introduced, in a package dyeing apparatus at a liquor ratio of 10:1 into a hot bath at 75-80°C containing, per litre, 0.35 g of Basic Yellow 028 0.06 g of Basic Red 046 3.05 g of Basic Blue mix Le A 28 537 11 g of caic. sodiumn sulphate g of 60% strength acetic acid g of benzyl-dodecyl-dimethyl-anmonium chloride.

The dyebath was then heated to 98*C.

The package density was 240 g/l.

Dyeing was carried out at this temperature for 45 in.

Dyeing was then completed in the usual manner. The quality of the dyeing corresponded to that of a hank dyeing.

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Claims (5)

1. Process for the dyeing of yarns made of natural wool, other animal hairs, silk or blends thereof with other native and/or synthetic fibres, characterised in that the yarn is exposed to dye liquor in a dyeing apparatus and that the yarn used is in the form of a cylindrical package having a package density of 160 to 280 g/l and further characterised in that a differential pressure of 0.05-0.5 bar, preferably 0.08- 0.3 bar, particularly preferably 0.1-0.3 bar is applied to the liquor, which pressure exceeds the loss in pressure caused by the dyeing apparatus and yam.

2. Process according to claim 1, characterised in that the package density is 180 to 280 g/l, preferably 210 to 260 g/l, particularly preferably 210 to 250 g/l.

3. Process according to claim 1, characterised in that the yarn is a carpet yarn or hand-knitting yarn. Process according to claim 1, characterised in that the yam is made of natural wool, other animal hairs, or blends thereof with other fibres. Process according to claim 1, characterised in that the dye liquor is recirculated at a volume of 10-35 litres per minute per kg of yam, preferably 10 to 1/min/kg, particularly preferably 12 to 30 1/min/kg. 25 6. Process according to claim 1, characterised in that a final temperature of 120°C, preferably 75-110°C, particularly preferably 80-98 0 C, very particularly preferably 80 to 95°C, is employed.

7. Process according to claim 1, characterised in that the dye liquor is pumped from the inside of the package through the yam to the outside of the package.

14- 8. A process for the dyeing of yarns substantially as hereinbefore described with reference to the examples. DATED this 26th day of May 1995. BAYER AKTIENGESELLSCHAFT By Its Patent Attorneys DAVIES COLLISON CAVE Process for the dyeing of yarns Abstract Yarns made of wool, other animal hairs, silk, polyamide, polyacrylonitrile (PAC) or blends thereof with other native and/or synthetic fibres can be dyed very uniformly in package form by selecting cylindrical packages and setting the package density at 160 to 280 g/l. Uniformity not only refers to conservation of the yarn bulk but also to the distribution of dye. 6o i Le A 28 537 Foreign countries