Method of improving thermal stability

Abstract

The invention relates to a method of improving the thermal stability of natural or synthetic polyamide fibre materials that are undyed, fluorescent whitened or dyed with reactive or disperse dyes, with the exception of metal complex dyes, wherein the fibre material is treated with a liquor comprising a compound of formula (1) Y1—X—Y2 (1) wherein X is a divalent aliphatic or cycloaliphatic radical and Y1 and Y2 are each independently of the other —OH, —CO—OR1, —NR1R2, —CO—NH—NR1R2 or —NH—CO—NH—NR1R2, wherein R1 and R2 are each independently of the other hydrogen; Q-Ĉalkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C5-C24-aryl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C6-C36aralkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; or C5-C24cycloalkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms.

Description

The present invention relates to a method of improving the thermal stability of undyed, fluorescent whitened or dyed, natural or synthetic polyamide fibre materials and to a textile auxiliary for use in that method.

In various textile-processing procedures (pretreatment, application of fluorescent whitening agents, dyeing, finishing), polyamide fibre materials are exposed to a heat treatment. Particularly in the case of undyed goods and goods which may have been fluorescent whitened, this frequently results in undesirable yellowing.

The action of heat also often results in undesirable effects before and after dyeing.

For example, a thermal pretreatment may lead to oxidative damage to the polyamide, which manifests itself, for example, in increased yellowing or loss of tear strength or which may have an adverse effect on dyeability.

During and after the dyeing process, a thermal treatment may result in unacceptable alterations in shade.

It has now been found that the above-mentioned disadvantageous effects can be substantially reduced by the use of a specific textile auxiliary.

The present invention relates to a method of improving the thermal stability of natural or synthetic polyamide fibre materials that are undyed, fluorescent whitened or dyed with reactive or disperse dyes, with the exception of metal complex dyes, wherein the fibre material is treated with a liquor comprising a compound of formula (1)

YrX—Y₂  (1)

wherein X is a divalent aliphatic or cycloaliphatic radical andYi and Y₂ are each independently of the other —OH, —CO—ORi, —NRiR₂, —CO—NH—NRiR₂ or —NH—CO—NH—NR₁R₂,wherein Ri and R₂ are each independently of the other hydrogen; Ci-Ci₂alkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C₅-C₂₄-aryl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C₆-C₃₆aralkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; or C₅-C₂₄CyClOalkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms.

Aliphatic radicals X in formula (I) are, for example, ethylene, propylene, trimethylene, propane-1,1-diyl, tetramethylene, hexamethylene, octamethylene and decamethylene or linear or branched alkylene that is interrupted by one or more O atoms or —NH—, —N(alkyl)- or —N(alkylene-NH₂)— groups.

Suitable cycloaliphatic radicals X are, for example, cyclohexane-1,2-diyl, cyclohexane-1,3-diyl and also

C_r Ci₂Alkyl as a radical Ri or R₂ can be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl or n-dodecyl.

A C₅-C₂₄aryl group as one of the radicals Ri-R₅ is, for example, phenyl, tolyl, mesityl, isityl, naphthyl or anthryl.

Suitable C₆-C₃₆aralkyl groups are, for example, benzyl and 2-phenylethyl.

Examples of C₅-C₂₄cycloalkyl are cyclopentyl and cyclohexyl.

In the method according to the invention, preference is given to the use of compounds of formula (1) wherein X is ethylene, tetramethylene, hexamethylene or octamethylene.

Preference is also given to compounds of formula (1) wherein Y₁ and Y₂ are —NR₁R₂, —CO—NH—NR₁R₂ Or —NH—CO—NH—NR₁R₂, wherein R₁ and R₂ is hydrogen, C_r C₁₂alkyl or C₅-C₂₄aryl.

Special preference is given to compounds of formula (1) wherein Y₁ and Y₂ are —NR₁R₂, —CO—NH—NR₁R₂ or —NH—CO—NH—NR₁R₂, wherein R₁ and R₂ are hydrogen, methyl or phenyl.

Examples of suitable compounds of general formula (1) are the compounds of formulae (101)-(104)

The compounds of formula (1) are known and are commercially available or can be synthesised by known methods.

The compounds of formula (1) used in the method according to the invention are present in the liquor advantageously in an amount of from 0.1 g/l to 100 g/l, preferably from 0.5 g/l to 50 g/l and especially from 1.0 g/l to 40 g/l.

As polyamide fibre material there comes into consideration natural polyamide fibre material, for example wool or silk, or synthetic polyamide fibre material, for example polyamide 6 or polyamide 6.6, or blends, for example wool/cellulose, polyamide/cellulose, polyamide/wool, polyamide/polyester or, especially, polyamide/elastane blends. The fibre material is preferably synthetic polyamide fibre material.

The textile material can be used in any form, for example in the form of fibre, yarn, woven fabric or knitted fabric.

The textile auxiliary according to the invention can be applied to the polyamide fibre material by customary dyeing or printing methods, for example by spray application or foam application, by the exhaust process or, preferably, the pad-dyeing process.

Special apparatus is not necessary. It is possible to use, for example, the customary dyeing apparatus, e.g. open baths, winch becks, jiggers or paddle, jet or circulatory apparatus.

In addition to comprising water and the textile auxiliary, the liquors may comprise further additives, for example wetting agents, anti-foams, levelling agents or agents that influence the properties of the textile material, for example softeners, flame-proofing agents or dirt-, water- and oil-repellants and also water-softeners and natural or synthetic thickeners, e.g. alginates and cellulose ethers.

As mentioned above, the method according to the invention can advantageously be used for the thermal stabilisation both of undyed polyamide (white goods), which may have been treated with a fluorescent whitening agent, and of dyed polyamide.

In the case of undyed or fluorescent whitened polyamide, the yellowing caused by heat treatment during heat-setting (hot air) or during moulding processes (contact heat) is prevented or reduced.

The method according to the invention is especially effective in the treatment of fluorescent whitened polyamide fibre material.

In the thermal stabilisation of dyed polyamide, the textile auxiliary according to the invention can be applied before, during or after dyeing.

When the auxiliary is used before dyeing, yellowing of the undyed goods during so-called pre-setting can be prevented or reduced. Furthermore, oxidative damage to the material during pre-setting, which can bring about a change in the dye uptake, is prevented.

The textile auxiliary according to the invention is preferably applied after dyeing of the polyamide fibre material with reactive or disperse dyes, with the exception of metal complex dyes.

The after-treatment of the dyed polyamide material with the textile auxiliary according to the invention brings about especially a certain degree of fibre protection during post-setting (heat setting) and effectively reduces the alteration in shade that frequently occurs in that process step, that is to say the shade remains constant, there is no dulling and no loss of colour strength.

In the case of undyed or fluorescent whitened polyamide materials, no appreciable reduction in whiteness is observed after the treatment with the textile auxiliary according to the invention.

It has also been found that, surprisingly, the treatment of the polyamide fibre material with the textile auxiliary according to the invention also brings about an improvement in fastness to ozone, NO_x and chlorine.

The invention accordingly relates also to a method of improving the fastness to ozone, NO_x and chlorine of natural or synthetic polyamide fibre materials that are undyed, fluorescent whitened or dyed with reactive or disperse dyes, with the exception of metal complex dyes, wherein the fibre material is treated with a liquor comprising a compound of formula (1), as defined above.

So-called storage yellowing, that is to say the yellowing that occurs during storage of the textile materials, can surprisingly also be effectively reduced by treatment with the textile auxiliary according to the invention. Resistance to storage yellowing is generally measured using the Courtaulds yellowing test. The polyamide fibre materials treated with the textile auxiliary according to the invention have a high Courtaulds fastness.

The textile auxiliaries according to the invention may comprise as further additives, for example, wetting agents, dispersants or pH regulators.

The following Examples serve to illustrate the invention. Unless otherwise indicated, temperatures are given in degrees Celsius, parts are parts by weight and percentages relate to percent by weight. Parts by weight relate to parts by volume in a ratio of kilograms to litres.

EXAMPLE 1

Treatment of Fluorescent Whitened Polyamide

(a) Whitening Process

A PA 6.6 textured tricot is treated by the exhaust process with an aqueous liquor containing 2.0% Uvitex® NFW liquid (fluorescent whitener, Ciba Specialty Chemicals) and 1.0 g/l of Ultravon® EL (dispersant, Ciba Specialty Chemicals). The pH is adjusted to 4.5 with acetic acid.

Liquor ratio 1:20, 30 min/95° C.

(b) Application of Auxiliary

The whitened fabric is treated by the pad-dyeing process with an aqueous liquor containing different amounts of adipic acid dihydrazide.

Liquor pick-up 100%; drying at 70° C.Whiteness according to Ganz: 230

The fabric is then subjected to a moulding test (30 s/210° C. and 60 s/210° C.); the whiteness values measured after the moulding test are given in Table 1:

TABLE 1
Adipic acid
dihydrazide [g/l]	Moulding	Whiteness (Ganz)
0	30 s/210° C.	152
0	60 s/210° C.	93
2	30 s/210° C.	198
2	60 s/210° C.	178
4	30 s/210° C.	205
4	60 s/210° C.	193
8	30 s/210° C.	208
8	60 s/210° C.	200
12	30 s/210° C.	208
12	30 s/210° C.	202

EXAMPLE 2

Treatment of Dyed Polyamide

A PA 6.6 textured tricot is dyed by the exhaust process with an aqueous liquor containing 0.02% Tectilon® Red 2B (Ciba Specialty Chemicals).

The fabric is then treated by the pad-dyeing process with an aqueous liquor containing 20 g/l of adipic acid dihydrazide (liquor pick-up 100%; pH=4-5), dried for 2 min at 120° C. and then subjected to heat-setting under different conditions. Table 2 gives the deviations in shade (DEF values) in comparison with the reference (untreated dyed fabric).

	TABLE 2
	Reference	Adipic acid dihydrazide
	[DEF]	[DEF]
	Untreated	0
	Dried	0.53	0.67
	Set 60 s/195° C.	2.80	1.06
	Set 30 s/210° C.	3.72	1.31
	Set 120 s/210° C.	12.40	3.15
	Set 240 s/210° C.	17.98	4.70

EXAMPLE 3

Treatment of Dyed Polyamide

A PA 6.6 textured tricot is dyed by the exhaust process with an aqueous liquor containing 0.65% Terasil® Flavin 8GFF (Ciba Specialty Chemicals).

The fabric is then treated by the pad-dyeing process with an aqueous liquor containing 20 g/l of adipic acid dihydrazide (liquor pick-up 100%; pH=4-5), dried for 2 min at 120° C. and then subjected to heat-setting under different conditions. Table 3 shows the deviations in shade (DEF values) in comparison with the reference (untreated dyed fabric).

	TABLE 3
	Reference	Adipic acid dihydrazide
	[DEF]	[DEF]
	Untreated	0
	Dried	0.20	1.23
	Set 60 s/195° C.	4.80	2.18
	Set 30 s/210° C.	5.95	3.18
	Set 120 s/210° C.	21.44	6.91
	Set 240 s/210° C.	32.35	8.99

EXAMPLE 4

Application to White Goods

A PA 6.6 textured tricot is, as described in Example 3, treated by the pad-dyeing process with an aqueous liquor containing 20 g/l of adipic acid dihydrazide (liquor pick-up 100%; pH=4-5), dried for 2 min at 120° C. and then subjected to heat-setting under different conditions. Table 4 shows the whiteness values (Ganz) in comparison with the reference (untreated fabric).

	TABLE 4
	Reference	Adipic acid dihydrazide
	whiteness (Ganz)	whiteness (Ganz)
Untreated	67.7
Dried	68.3	62.7
Set 60 s/195° C.	28.4	59.7
Set 30 s/210° C.	13.5	44.4
Set 120 s/210° C.	−73.6	22.6
Set 240 s/210° C.	−157.7	−11.1

EXAMPLE 5

Wash-Fastness of the Auxiliary

As described in Example 4, a PA 6.6 textured tricot is treated with an aqueous liquor containing 20 g/l of adipic acid dihydrazide (ADH). Samples of the treated fabric are then washed three times, six times and ten times.

After a moulding test, the whiteness according to Ganz is measured (Table 5).

	TABLE 5
	Moulding
	Whiteness (Ganz)	Whiteness (Ganz)
	reference (untreated)	treated with ADH
Washing 40° C.	3×	6×	10×	3×	6×	10×
Set 30 s/210° C.	27.6	19.2	23.0	39.9	41.4	40.1
Set 120 s/210° C.	−114.1	−127.5	−136.9	8.5	10.1	−4.1
Set 240 s/210° C.	−140.0	−129.9	−136.4	2.4	9.7	2.4

EXAMPLE 6

Moulding Fastness of Dyed Polyamide

A PA 6.6 textured tricot is, as described in Example 2, dyed with Tectilon® Red 2B and then treated with adipic acid dihydrazide. After the moulding test, the deviations in shade (DEF values) in comparison with the reference (untreated dyed fabric) are measured (Table 6).

	TABLE 6
	Reference	Adipic acid dihydrazide
	[DEF]	[DEF]
	Untreated	0
	Dried	1.30	1.45
	Set 60 s/195° C.	2.66	1.54
	Set 30 s/210° C.	8.35	2.00
	Set 120 s/210° C.	12.83	3.25

EXAMPLE 7

Moulding Fastness of Dyed Polyamide

A PA 6.6 textured tricot is, as described in Example 4, dyed with Terasil® Flavin 8GFF and then treated with adipic acid dihydrazide. After the moulding test, the deviations in shade (DEF values) in comparison with the reference (untreated dyed fabric) are measured (Table 7).

	TABLE 7
	Reference	Adipic acid dihydrazide
	[DEF]	[DEF]
	Untreated	0
	Dried	0.52	1.45
	Set 60 s/195° C.	4.25	2.22
	Set 30 s/210° C.	4.84	3.13
	Set 120 s/210° C.	8.16	4.93

EXAMPLE 8

Moulding Fastness of Treated White Goods

A PA 6.6 textured tricot (white goods) is, as described in Example 4, treated with adipic acid dihydrazide. After the moulding test, the whiteness (Ganz) in comparison with the reference (untreated fabric) is measured (Table 8).

	TABLE 8
	Reference	Adipic acid dihydrazide
	whiteness (Ganz)	whiteness (Ganz)
Untreated	68.9
Dried	67.9	63.4
Set 60 s/195° C.	26.7	45.8
Set 30 s/210° C.	16.8	41.8
Set 120 s/210° C.	1.1	27.4

EXAMPLE 9

Treatment of Fluorescent Whitened Polyamide

As described in Example 1, a PA 6.6 textured tricot is fluorescent whitened with Uvitex® NFW liquid and then treated with adipic acid dihydrazide, dried at 60° C. and then subjected to heat-setting under different conditions. Table 9 shows the measured whiteness values according to Ganz in comparison with the reference (fluorescent whitened fabric, without ADH treatment).

	TABLE 9
	Whiteness	Whiteness
	(reference)	(ADH treatment)
	Untreated	243.6	204.9
	Set 30 s/190° C.	230.3	219.3
	Set 60 s/190° C.	150.7	210.6
	Set 30 s/210° C.	174.6	216.5
	Set 60 s/210° C.	−38.2	204.8

EXAMPLE 10

Treatment of Fluorescent Whitened Polyamide

As described in Example 1, a PA 6.6 textured tricot is fluorescent whitened with Uvitex® NFW liquid by the exhaust process. The fabric is then treated by the exhaust process with an aqueous liquor containing 2.0% N,N′-diphenylethylenediamine (DPEDA) (pH=5.0; liquor ratio 1:20; 30 min/98° C.) and then subjected to heat-setting under different conditions. Table 10 shows the measured whiteness values according to Ganz in comparison with the reference (fluorescent whitened fabric, without DPEDA treatment).

	TABLE 10
	Whiteness	Whiteness
	(reference)	(DPEDA treatment)
	Untreated	243.6	197.3
	Set 30 s/190° C.	223.3	196.7
	Set 60 s/190° C.	150.7	175.5
	Set 30 s/210° C.	174.6	179.8
	Set 60 s/210° C.	−38.2	128.7

Claims

1. A method of improving the thermal stability of natural or synthetic polyamide fibre materials that are undyed, fluorescent whitened or dyed with reactive or disperse dyes, with the exception of metal complex dyes, wherein the fibre material is treated with a liquor comprising a compound of formula (I) Y1—X—Y2  (1)wherein X is a divalent aliphatic or cycloaliphatic radical andY1 and Y2 are each independently of the other —OH, —CO—OR1, —NR1R2, —CO—NH—NR1R2 or —NH—CO—NH—NR1R2,wherein R1 and R2 are each independently of the other hydrogen; C1-C12 alkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C5-C24 aryl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C6-C36 aralkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; or C5-C24 cycloalkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms.

2. A method according to claim 1 wherein X is ethylene, tetramethylene, hexamethylene or octamethylene.

3. A method according to claim 1 wherein Y1 and Y2 are —NR1R2, —CO—NH—NR1R2 or —NH—CO—NH—NR1R2, wherein R1 and R2 are hydrogen, C1-C12 alkyl or C5-C24 aryl.

4. A method according to claim 1 wherein Y1 and Y2 are —NR1R2, —CO—NH—NR1R2 or —NH—CO—NH—NR1R2, wherein R1 and R2 are hydrogen, methyl or phenyl.

5. A method according to claim 1 wherein the compound of formula (1) is a compound of formula (101)-(104)

6. A method according to claim 1 wherein the compound of formula (1) is present in the liquor in an amount of from 0.1 g/l to 100 g/l.

7. A method according to claim 1 wherein the treatment of the fibre material with the liquor comprising a compound of formula (1) is effected by the pad-dyeing process.

8. A method according to claim 1 wherein fluorescent whitened polyamide fibre material is treated.

9. A method according to claim 1 wherein polyamide fibre material that has been dyed with reactive or disperse dyes, with the exception of metal complex dyes, is treated.

10. A method of improving the fastness to ozone, NOx and chlorine of natural or synthetic polyamide fibre material that is undyed, fluorescent whitened or dyed with reactive or disperse dyes, with the exception of metal complex dyes, wherein the fibre material is treated with a liquor comprising a compound of formula (1) Y1—X—Y2  (1)wherein X is a divalent aliphatic or cycloaliphatic radical andY1 and Y2 are each independently of the other —OH, —CO—OR1, —NR1R2, —CO—NH—NR1R2 or —NH—CO—NH—NR1R2,wherein R1 and R2 are each independently of the other hydrogen; C1-C12 alkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms C5-C24 aryl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; C6-C36 aralkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms; or C5-C24 cycloalkyl unsubstituted or substituted by one or more hydroxy, amino or carboxyl groups or halogen atoms.