WO2009000660A2

WO2009000660A2 - Method for preventing yellowing

Info

Publication number: WO2009000660A2
Application number: PCT/EP2008/057364
Authority: WO
Inventors: Herbert Bachus; Christian Dörfler
Original assignee: Cht R. Beitlich Gmbh
Priority date: 2007-06-23
Filing date: 2008-06-12
Publication date: 2008-12-31
Also published as: EP2160489A2; WO2009000660A3; EP2160489B1; DE102007028997A1

Abstract

The invention relates to materials which contain polyamide and are resistant to yellowing, having a surface finish containing carbodihydrazide, a method for this finishing, and the use of materials containing polyamide which are produced accordingly.

Description

Method for yellowing inhibition

The invention relates to highly yellowing-resistant polyamide-containing materials having surface finish containing carbodihydrazide, a method of finishing, and the use of appropriately prepared polyamide-containing materials.

Polyamides have a sufficiently high weathering and age resistance for a variety of applications. If desired, in outdoor applications by a special coloring such as carbon black, the durability can be further increased.

Dyeing with soot easily avoids the problem of yellowing, which frequently occurs in plastics - but does not eliminate it. This becomes particularly important if one is not interested in a very dark color of the finished plastic part. In such cases, a yellowing, caused either by oxidative aging processes or even by the thermal treatment during the manufacturing process is negatively noticeable.

A typical thermal treatment process in this context is thermosetting, in which the product in question is subjected to a heat treatment with hot water, steam or dry heat and thus shrinks, whereby a subsequent undesirable dimensional change is prevented. Temperatures of 200 ⁰ C and above are quite common here. Another method is the Molden, in which the materials used are brought by heat of a (press) tool (ie, by contact heat) in an appropriate form. This method is used, for example, in the production of brassieres.

The yellowing does not arise here only with untreated or optically brightened polyamide-containing material, which is usually yellow-white or milk-white depending on the type.

Even with colored polyamide-containing material - a coloring is usually achieved with acid or metal complex dyes - this problem occurs. For colored materials, the yellowness changes the original color shade in an undesirable manner.

In addition to yellowing in the course of thermofixing or Moldens also various aggressive compounds such as nitrogen oxides (NOx), ozone or chlorine-containing oxidizing agents exert a negative impact on the weathering or age resistance of polyamide-containing materials.

Therefore, in order to suppress this problem of yellowing, various auxiliaries have been developed. In this context, it should be particularly noted that some textiles, such as brassieres or stockings, are worn directly on the skin and any chemicals used after the application must have sufficient skin compatibility. Even with carpets, for example, a health safety of the chemicals used, since direct skin contact can also take place here.

EP 0 436 470 B1 describes in this connection a photochemical stabilization of dyed polyamide fiber materials by the use of various complexes of bisazomethines, acylhydrazones, semicarbazones or thiosemicarbazones of aromatic carbonyl compounds with copper as the central metal. The use of the toxic heavy metal copper, however, makes corresponding textile auxiliaries not only environmentally friendly but also health-friendly aspects of concern.

JP 60-81370 describes a process for treating textile products of polyamide fibers or polyamide fiber blends which have been dyed with acidic or metal-containing dyes. The thus dyed textile products are treated with an antioxidant from the group of carbazides or hydrazines, in particular 1,6-hexamethylene bis (N, N-dimethylsemicarbazide) and adipic dihydrazide [ADH].

WO 2006/045721 A1 describes predominantly dicarboxylic acid bishydrazides, and of these in particular ADH, for improving the aging stability of undyed, optically brightened or natural or synthetic polyamide fiber materials dyed with reactive or disperse dyes, with the exception of metal complex dyes.

A disadvantage of the last two methods is in particular the fact that for a sufficient yellowing inhibition a relative large amount of textile adjuvant must be used. From the relatively low water solubility of the excipient, there is a further limitation.

The object of the present invention was therefore to provide a more effective antioxidant for yellowing inhibition. Furthermore, the antioxidant of the invention should have much lower umweit- and / or harmful properties. Of course, both factors are mutually dependent, because an increased effectiveness implies the use of a lower amount of the antioxidant, which generally results in a significantly lower environmental and / or health burden.

In a first embodiment, the object underlying the invention is solved by a polyamide-containing material having a surface finish containing carbodihydrazide [CDH].

For the purposes of the present invention, surface finishing means a refining of the material in question, in which case the CDH, in contrast to a surface coating, may also be on the inner surface of the material (caused, for example, by diffusion of the CDH under the equipment conditions).

Surprisingly, it has been found that the yellowing inhibition is in part exceeded by the use of CDH in comparison to the current industrial standard ADH. It is also particularly unexpected that such materials, whose surface finish comprises this relatively small molecule with only one carbon atom but four nitrogen atoms, do not cause skin irritation to OECD 404 or sensitization to OECD 406.

For the purposes of the present invention, the polyamide-containing material need not necessarily be an untreated or undyed material. It is also quite possible that it is an optically brightened material or colored with reactive, acid, disperse or metal complex dyes.

Preferred optical brighteners include the following compounds: stilbene-based compounds, especially alkylation products of 4,4'-diaminostilbene-2,2'-disulfonic acid; Compounds in which two heteroaromatic radicals are linked to one another via an ethylene bridge; Coumarin derivatives, in particular having an amino group or an N-heterocycle instead of the amino group; l, 3-diphenyl-2-pyrazolines; Naphthalimides, especially N-methyl-4-methoxynaphthalimide; Compounds containing a fused aromatic and a heteroaromatic, in particular 2,4-dimethoxy-6- (1-pyrenyl) -1, 3,5-triazine.

Preferred dyes are common dyes for polyamides, especially acid and metal complex dyes.

The polyamide-containing material can contain not only natural polyamides, in particular wool and / or silk, but also synthetic polyamides. Examples of synthetic polyamides according to the present invention are: polyamide [PA] 4, PA 5, PA 6, PA 11, PA 12, PA 6.6, PA 6.10, PA 6.12, PACM 12, polyaramids such as Nomex and Kevlar, copolyamides such as PA 66/6 and PA 11/12 and block copolymers of polyamides and other polymers, in particular polyethers.

Other constituents of the polyamide-containing material are, in addition to polyamides, other polymers, in particular polyesters, polysaccharides, in particular cotton and / or viscose, polyurethanes and / or polyolefins, and also auxiliaries and / or effect substances customary for polymers, for example antistatic agents, colorants, flame retardants, fillers Nucleating agents, pigments, reinforcing fibers and / or plasticizers possible.

The polyamide-containing material according to the invention can be present in the form of fibers, nonwovens, mesh, woven or knitwear and, as such, can also be further processed into secondary products.

In a second embodiment, the object underlying the invention is achieved by a process for finishing surfaces of polyamide-containing material, which comprises contacting the carbodihydrazide dissolved or dispersed in a liquid with the surface and subsequently removing the liquid ,

The carbodihydrazide solution or dispersion can be brought into contact with the surface by the pulper or, in particular, by padding (also known as padding). The padding process offers in comparison to the exhaust especially under Environmental aspects have great advantages, since it usually requires less solvent. In addition, it also ensures a more homogeneous application.

The carbodihydrazide can be applied in the process according to the invention before staining or optical brightening. However, it is preferred if this application step is followed by a possible lightening and / or coloring, since only then is the antioxidant used optimally utilized.

As a solvent or dispersant for the carbodihydrazide is used in the process according to the invention advantageously water. Not only does water have high solubility for CDH and the other common additives contained in the liquor, it also has the advantage of high environmental compatibility.

The amount of CDH in the liquor should be adjusted to a range of 0.1 g / L to 20 g / L, in particular from 0.5 to 10 g / L. Lower concentrations have the disadvantage that the CDH-containing liquor would have to be applied several times to the polyamide-containing material in order to achieve the desired efficiency. Higher concentrations are not required for reasons of high efficacy.

In addition to carbodihydrazide, the liquor used may contain other customary process or effect chemicals, in particular wetting agents, plasticizers, oleo and / or hydrophobizing additives or thickeners. After the application of the carbodihydrazide, a heat-setting or molding step may be followed, in which the antioxidant action of the carbodihydrazide is utilized. It is possible that the fleet mainly removing solvents and / or dispersants in the course of these thermal processing steps to remove what is of course favored insofar as can be reduced in this way, the number of required process steps. However, the solvent and / or dispersant can also be removed beforehand in a separate step.

Another embodiment of the present invention is the use of a solution or dispersion containing a carbodihydrazide as a textile auxiliary.

In particular, it has been found that CDH-treated textiles based on polyamide have a very high stability in the yellowing inhibition against thermal influences and / or oxidizing agents. Under thermal influences are here in particular treatment method of polyamide-containing materials to understand, which are carried out at higher temperatures, such as thermosetting or Molden. Oxidizing agents are to be understood as meaning in particular nitrogen oxides, ozone or chlorine-containing oxidizing agents.

embodiments

In the following examples, the degrees of whiteness are given in Berger units. Example 1: Treatment of untreated polyamide

An undyed knit PA 6.6 was added with an impregnation solution

100% liquor pickled and dried for 30 s at 120 ⁰ C, then in

Example 1.A) for 45 s at 200 ⁰ C heat-set or in

Example 1.B) for 45 s at 210 ⁰ C gemoldet

Example 2: Treatment of optically brightened polyamide

Polyamide 6.6 knit fabric was lightened at a liquor ratio of 1:10 with 1.0% Tuboblanc® MA. The pH was adjusted to 4 with acetic acid, the treatment was carried out at 95 ^° C. and for 30 minutes. Thereafter, rinsed warm and cold and dried at 120 ⁰ C.

Subsequently, the pad at 100% liquor pickup was treated with the stated amount of antioxidant, the pH was adjusted to 5 with acetic acid. Was dried again at 12O ⁰ C. After thermofixing, basic white [GW] and fluorescence [F] are assessed.

Example 3: Treatment of colored polyamide (Moldeni

Polyamide 6.6 knitwear was dyed at a liquor ratio of 1:10 with acid dyes. At the beginning of cold 2 g / L Sarabid EP and 0.5 g / L Meropan EF were submitted, after 10 min 0.02% of a Bezanyl ^® - acid dye is added, is heated for further 10 min at 2 ° C / min to 98 0C, Treated for 30 min at this temperature, then cooled at 2 ° C / min to 60 ⁰ C and rinsed. As dyes Bezanyl ^® Red E-3G 200 Bezanyl ^® Blue E2R 200 Bezanyl ^® Violet FB or Bezanyl ^® Orange N-GR were used.

After drying at 120 ⁰ C were 0.5, 0.75 or 1 g / L CDH and applied as Comparative Example 1 or 2 g / L ADH in pad at 100% liquor pickup, dried at 120 ⁰ C and at 210 ⁰ C respectively 30, 60 or 120 s gemoldet.

Result:

ADH and CDH worked very efficiently compared to the samples without antioxidant, 1 g / L ADH improved the result, good results were obtained only with 2 g / L ADH or CDH according to the invention already at 0.5 to 0.75 g / L , 1 g / L CDH worked best.

Example 4: treatment of dyed polyamide (heat setting ^')

The treatment was carried out analogously to Example 3, but instead of Moldens at 200 ⁰ C and 210 ⁰ C each 30 or 60 s was heat-set.

Result:

With the hydrazides, the color change was well inhibited. 1 g / L CDH scored the same, sometimes even slightly better results than the comparative example with 2 g / L ADH. Example 5: Thermofixing of polyamide and subsequent dyeing

The treatment was carried out analogously to Example 4, but first the antioxidant was applied, then heat-set and dyed at the end.

The result reflected the same tendency as in Example 4, 1 g / L of CDH was comparable in effect or better than 2 g / L of ADH.

Example 6: NOv Verailbunα

A product of 40% of PA 6/60% elastane ^® with a base White of 81 Berger units was padded with antioxidant at 50% wet pickup, and once adjusted without pH adjustment and once with citric acid to a pH of 5.5 was then dried at 120 ⁰ C each.

The NOχ-authenticity was tested according to EN ISO 105-G01 "NO _x -gasing heavy" and assessed according to gray scale (1 worst, 5 best).

Result: CDH was many times better than ADH. Example 7: La stability and effectiveness of aqueous CDH

Analogously to Example 1, instead of pure CDH, the 10-fold amount of a 10% strength solution which had been previously stored for 2 months at room temperature was used.

All results are in the range of Example 1, i. a 10% solution of CDH was sufficiently storage stable to settlements and achieved the same effect at the appropriate use concentration in the textile application.

Example 8: Sensitization and skin irritation

An untreated raw ash PA 6.6 was cleaned in acetone, then thoroughly rinsed with water and dried. Thereafter, 3.75 g / L of CDH were padded at 100% liquor pickup and dried at 120 ⁰ C. It was then gemoldet at 200 ⁰ C for 30 s. The product was tested for sensitization to OECD 406 and skin irritation according to OECD 404.

The result was "non-sensitizing" and the Primary Skin Irritation Index (PSI) was 0, not irritating to the skin.

Claims

claims:

1. Polyamide-containing material with a surface finish containing carbodihydrazide.

2. Material according to claim 1, characterized in that the polyamide-containing material is dyed, undyed or optically brightened.

3. Material according to one of claims 1 or 2, characterized in that the polyamide-containing material contains natural polyamides, especially wool and / or silk.

4. Material according to one of claims 1 or 2, characterized in that the polyamide-containing material contains synthetic polyamides.

5. Material according to any one of claims 1 to 4, characterized in that the polyamide-containing material contains other polymers, especially polyesters, polysaccharides, polyurethanes and / or polyolefins.

6. Material according to any one of claims 1 to 5, characterized in that it is in the form of fibers, nonwovens, mesh, woven or knitted fabric.

7. A process for finishing surfaces of polyamide-containing material, characterized in that one in a liquid dissolved or dispersed carbodihydrazide with the surface in contact and then removes the liquid.

8. The method according to claim 7, characterized in that applying the carbodihydrazide solution or dispersion by exhaust or in particular by padding process on the surface.

9. The method according to any one of claims 7 or 8, characterized in that the applied before the carbodihydrazide, but especially after the dyeing and / or optical brightening.

10. The method according to any one of claims 7 to 9, characterized in that one uses a polyamide-containing material containing natural polyamides, especially wool and / or silk.

11. The method according to any one of claims 7 to 9, characterized in that one uses a polyamide-containing material containing synthetic polyamides.

12. The method according to any one of claims 7 to 11, characterized in that one uses a polyamide-containing material containing other polymers, especially polyesters, polysaccharides, polyurethanes and / or polyolefins.

13. The method according to any one of claims 7 to 12, characterized in that one uses as a polyamide-containing material fibers, nonwovens, mesh, woven or knitted fabric.

14. The method according to any one of claims 7 to 13, characterized in that one uses as a solvent or dispersant for the carbodihydrazide water.

15. The method according to any one of claims 7 to 14, characterized in that one uses a liquor containing an amount of 0.1 g / L to 20 g / L, in particular from 0.5 to 10 g / L, of carbodihydrazide.

16. The method according to any one of claims 7 to 15, characterized in that one uses a liquor containing conventional process or effect chemicals, in particular wetting agents, plasticizers, oleo and / or hydrophobizing additives or thickeners.

17. The method according to any one of claims 7 to 16, characterized in that the product is heat-set or molded after treatment with carbodihydrazide.

17. Use of carbodihydrazide or a solution or dispersion containing this as a textile auxiliary.

19. Use according to claim 18 for the stabilization of textiles against thermal influences and / or oxidizing agents.

20. Use according to claim 19 for stabilizing textiles against nitrogen oxides, ozone or chlorine-containing oxidizing agents.