EP0705357A1

EP0705357A1 - Use of carboxymethylated guargalactomannan as a sizing agent

Info

Publication number: EP0705357A1
Application number: EP94920454A
Authority: EP
Inventors: Hans-Peter Miemietz; Kaspar Schlueter; Sieg Waltenberger-Scharffetter; Bernhard Wuestnienhaus
Original assignee: Henkel AG and Co KGaA
Current assignee: Cognis IP Management GmbH
Priority date: 1993-06-24
Filing date: 1994-06-15
Publication date: 1996-04-10
Anticipated expiration: 2014-06-15
Also published as: ES2101547T3; JPH08511832A; DE4321016A1; WO1995000696A1; EP0705357B1; US5612475A; JP3300358B2; DE59402765D1

Abstract

The invention concerns the use of alkali-metal salts of carboxymethylguargalactomannan with a degree of substitution of less than 0.15 as sizing agents, plus a method of sizing natural and/or synthetic yarn using these compounds.

Description

"Carboxymethylated guar galacto annan as sizing agent"

The present invention relates to the use of alkali metal salts of carboxymethylguargalactomannans with degrees of substitution below 0.15 as sizing agents, and to a process for sizing natural and / or synthetic yarns using these compounds.

It is known that sizing agents are used in the weaving process in order to give the warp thread sufficient strength and, on the other hand, to stick protruding fibers to the yarn body or, in the case of filament yarns, to bond the individual filaments together. This increases the strength of the warp thread during weaving. Well-known sizing agents are native or modified starches, carboxymethylcelulloses, polyvinyl alcohols and polyacrylates. The sizing agents usually have to be removed from the fabric again after the weaving process, since they would otherwise interfere with the subsequent finishing processes. One way of removing the sizing agents is to simply wash them out with water, which presupposes that the sizing agents can be washed out with water. Such water-washable sizing agents are, in particular, carboxymethyl-substituted starches, carboxymethyl celluloses, polyvinyl alcohols and polyacrylates. Except for the carboxymethyl-substituted starches, the other sizing agents show only poor biodegradability. The carboxymethylated starches are readily biodegradable, but leave something to be desired in their sizing effect, which is why they have to be used in large quantities, which in part has the advantage of good biodegradability is compensated again.

The poor biodegradability of the other sizing agents is particularly disadvantageous because sizing agents make up the main part of the wastewater pollution caused by the textile industry. It is assumed that the sizing agents cause up to 80% of the textile wastewater pollution. There has been no shortage of attempts to provide sizing agents with high efficiency and good water washability, which have improved biodegradability.

In Melliand Textile Reports 8/1983, 526-529, for example, different galactomannans, including guar galacto annans, are described as sizing agents. This article mentions the advantages and disadvantages of the galactomann size, as well as its good biodegradability. Examples of galactomannic sizing are those of guar galactomannan, tamarind kernel flour and locust bean gum (carubin). Now, however, the present article claims that guar galactomans are not a sensible alternative to the sizes used so far due to their poor adhesive strength. On the other hand, the carboxymethyl derivatives of guargalactomannan are not mentioned in the article.

It was therefore an object of the present invention to provide biodegradable sizing agents which are water-washable and which, at least in their sizing effect, are comparable or even better than the sizing agents used to date, such as carboxymethyl cellulose.

Surprisingly, it was found that the object can be achieved if alkali metal salts of carboxymethylguargalactomannans with degrees of substitution below 0.15 are used as sizing agents. Our own investigations have shown that special guargalacto anane derivatives, namely the alkali salts of carboxymethylated guargalactomannan, have good adhesion and good biodegradability if they have a low degree of substitution.

An object of the present invention is therefore the use of alkali salts of carboxymethylguargalactomannans with degrees of substitution below 0.15 as sizing agents for sizing natural and / or synthetic yarns.

For the purposes of the invention, the terms carboxymethylated guargalactomannan and carboxymethylguargalactomannan are used synonymously.

Guar galactomannan products are produced from the endosperm of guar seeds. Native guar products consist of galactomannans with small amounts of protein, fiber and fat as well as very small amounts of alkali and alkaline earth metals, iron and some trace elements. The chemical structure of the galacto annane in guargalactomannan is described as a linear mannose chain, the mannose units being condensed with one another by (1 → 4) β-glycosidic bonds, and every second mannose unit being substituted by the hydrogen the primary hydroxyl group carries a galactose unit. The galactose molecule is linked to the mannan main chain by a (1 -> 6) - - glycosidic bond. The two sugar units have hydroxyl groups in the cis position, in contrast to glucose, the monomer of cellulose and the starch, which all hydroxyl groups have in the trans position. The cis-hydroxyl groups and the stretched rigid structure of the galactomannan are the reason for many unique properties of guargalactomannan and its derivatives. Guarga lactomannan can be modified like other polysaccharides. One type of modification is carboxymethylation, which produces anionic guar galactomannane derivatives. The carboxymethylation can be analogous to the see US 2520 161 and US 2,477,544 by reacting the guar galactomannan with a cold aqueous solution of alkali metal hydroxides and then treating the alkali metal derivatives of guar galactomannan with a halogenated fatty acid or its salt. You can also carboxymethylate with other carboxylic acids or their salts, such as with glycolic acid or with sodium glycolate. Depending on the amount of reactants used and reaction times and conditions, different degrees of substitution of guar galactomannan are obtained. The maximum possible degree of substitution is 3. For the purposes of the invention, preference is given to those alkali metal salts of carboxylmethyl guar which have degrees of substitution from 0.05 to 0.15.

According to German patent DE 37 09 698, carboxymethylated guar galactomannan with degrees of substitution of 0.22 was used as a sizing agent in a mixture of hydroxyalkyl guar galactomannan and hydroxyalkyl casagalactomannan. According to the present application, however, alkali salts of carboxymethylated guar galactomannan with low degrees of substitution are to be used, since our own experiments have shown that their adhesive strength is significantly better and that their biodegradability is superior.

Guargalactomannan products show molecular weights that are in the range of 0.5 to 11 * 10 ^* ^. If a modification such as carboxymethylation takes place, the guar galactomannan products are generally depolymerized at the same time. Since the molecular weight determination of such polymers can cause difficulties in practice, a move has been made to indicate the viscosity associated with this instead of the molecular weight. According to one embodiment of the present invention, alkali metal salts of oxidatively degraded carboxymethylguargalactomannan are used which, as a 4% strength by weight aqueous solution, have a Höppler viscosity at 20 ° C. between 10 and 3000 mPas, preferably between 20 and 500 mPas.

Due to the method of preparation according to the two American patents already cited, the alkali metal salts of carboxymethylguargalaktoman¬ nans may contain alkali metal halides as impurities. For the purposes of the invention, preference is therefore given to using alkali metal salts of carboxymethylguargalactomannans which have alkali halide impurities of less than 10% by weight, preferably less than 5% by weight. The impurities in alkali halides can be reduced in a manner known per se, for example by washing out with a methanol / water mixture. Another contamination which can occur after the above manufacturing processes are the salts of the glycolic acids, which can also be removed, for example, by washing with a methanol / water mixture.

Of the alkali salts of carboxymethylguargalactomannans, the corresponding sodium salt is particularly preferred.

For the purposes of the invention, the alkali metal salts of carboxymethylated guargalactomannan can be used alone or in any mixture with conventional sizing agents, preferably with the starch derivatives, polyvinyl alcohols and polyacrylates. The mixing ratios are selected depending on the desired size properties and are in the amounts customary for the person skilled in the art.

The alkali salts of carboxymethylguargalactomannan can be used on all weaving machines as well as on all sizing machines such as marksmen, rapier and air-jet weaving machines. In the sense of the invention, the yarns can be both staple yarns and continuous yarns. The yarns can be of natural origin, for example made of cotton or regenerated cellulose, and / or synthetic origin such as cellulose acetate, Polyester, polyacrylonitrile and polyamide. Particularly good results are achieved for cotton and regenerated cellulose and their blends with polyester.

The size coating of alkali metal salts of carboxymethylguargalactomannan with degrees of substitution below 0.15, alone or in a mixture with the usual sizes, is in the range from 1 to 25% by weight, based on the dry weight of the yarn. The amount of alkali metal salts of carboxymethylated guargalactomannan is therefore in the range from approximately 1/3 to half of 100 parts of starch size and in the latter case in the range of the known synthetic sizes.

When using the alkali metal salts of carboxymethylguarga lactomannans according to the invention, there is an excellent sizing effect. Furthermore, the alkali metal salts of carboxymethylguargalactomannans show excellent biodegradability, which is even better at these low degrees of substitution than with only slightly more highly substituted guargalactomannans. In addition, alkali salts of carboxymethyl guar galactomannan dissolve quickly and free of lumps in the water, show no signs of skin formation, do not foam in the liquor and can be washed out with water.

Another object of the present invention is a method for sizing natural and / or synthetic yarns in a known manner with alkali salts of carboxymethylguargalakto annans, which is characterized in that alkali salts of carboxymethylguargalactomannans are used with degrees of substitution below 0.15. The application of the alkali salt of carboxymethylguargalactomannan takes place, as is customary for sizing agents, as an aqueous solution with product concentrations of 10 to 150 g / l in the usual sizing machines. Example

A. Tested alkali salts of carboxymethyl guar galactomannan

For example, Aktivge¬ Wasserge¬ NaCl content Substi¬ pH value viscosity in content in% by weight at 4 Höppler% by weight% by weight% by weight 4% by weight

20 ° C

AI 91.5 6.4 0.32 0.13 6.1 77

A2 80.7 3.2 4.33 0.1 6.4 40

See 1 76.8 2.0 8.61 0.33 5.6 21

The viscosity was determined according to Höppler in accordance with DIN 53015. Tested the above sodium salts of carboxymethylguargalactomannans, for example according to US 2477 544 or US 2520161 producible.

B. Determination of the sizing effect

A scrubbing tester was developed to determine the sizing effect and was developed by the TN0, Delft / NL fiber institute.

In this abrasion tester, 30 individual threads were clamped in such a way that they are subject to a combined stress consisting of thread-thread and thread-metal friction. The deflection pins were mounted on a strip that was moved up and down by a motor. A trailer weight of 50 g ensured for tensile stress. After scrubbing until all threads broke, the number of scrubbing cycles being recorded for each thread break, the test was evaluated from a statistical point of view. The median value, which is characterized in that 50% of all values are above and 50% below this value, was taken as a measure of the size effect.

The warp yarns were sized on a laboratory sizing machine from Sucker, Mönchengladbach, with 40 threads being sized from the creel. Raw white cotton wool ring yarns of fineness N 50/1 were routinely used.

The following test conditions existed:

Test conditions

Yarn Nm 50/1, CO ring

Setting 30 threads / cm

Dip roller 144 daN

Squeeze roller 0.5 bar (large manometer)

Temperature trough approx. 85 ° C

Drying temperature approx. 130 ° C

Speed approx. 30 m / min

Table 1 summarizes the abrasion resistance found at various sizes (according to DIN 54285), expressed as the number of strokes up to the thread break (median value). Table 1: abrasion resistance table

g / 1 product size content number of

Strokes

30 AI) 3.0 120

50 AI) 5.0 336

90 AI) 9.8 983

30 A2) 3.4 81

50 A2) 5.0 205

80 A2) 8.9 596

30 See 1) 3.4 76

50 See 1) 4.9 142

90 See 1) 9.3 385

120 See 1) 13.4 607

30 See 2) 2.9 95

50 See 2) 4.8 187

90 See 2) 9.6 481

It can be seen from Table 1 that the sodium salt of carboxymethylated guar galactomannan with higher degrees of substitution (see FIG. 1) shows poorer sizing effects at the same or higher sizing contents than those with degrees of substitution below 0.15, since after a few strokes the thread breaks occurs. Furthermore, Table 1 shows that the sodium salt of carboxymethylguarglactomannans (AI) and A2)) according to the invention in the Sizing effect is clearly superior to the previously used carboxymethyl cellulose derivative Horsil NV-P (registered trade name of Henkel KGaA (cf. 2)).

C. Biodegradability

A short-term Zahn-Wellens test (ZWT) was carried out to determine the biodegradability. The test matrix is hardened, distilled water to which an amount of wet sludge corresponding to approximately 1 g / 1 dry matter was added. Incubation was carried out for 7 days at 19 to 25 ° C. with stirring and constant air supply. Regular DOC determinations were carried out. The results for AI) and cf. 1) are summarized in Table 2.

Table 2: Biodegradability

Test substance Test concentration% DOC decrease after days based on mg DOC / 1 at 0 hourly value 0.25

AI) 100 23 90 93

See 1) 100 30 70

It can be seen from Table 2 that the compounds used according to the invention can be broken down much better than the somewhat more highly substituted guargaactomannan derivatives.

Claims

Patent claims

1. Use of alkali metal salts of carboxymethylguargalaktomannans with degrees of substitution below 0.15 as a sizing agent for the sizing of natural and / or synthetic yarns.

2. Use according to claim 1, characterized in that alkali metal salts of carboxymethylguargalactomannans are used with degrees of substitution from 0.05 to 0.15.

3. Use according to claim 1 or 2, characterized in that alkali salts of oxidatively degraded carboxymethylguargalactomannan are used which, as a 4% by weight aqueous solution, have a Höppler viscosity at 20 ° C between 10 and 3000, preferably between 20 and 500 mPa-s.

4. Use according to one of claims 1 to 3, characterized in that alkali metal salts of carboxymethylguargalactomannans are used which have alkali halide impurities below 10, preferably below 5% by weight.

5. Use according to one of claims 1 to 4, characterized in that the alkali metal salts of carboxymethylguargalactomannans are used in a mixture with conventional sizing agents, preferably with starch derivatives, polyvinyl alcohols and polyacrylates.

6. Use according to one of claims 1 to 5, characterized in that the alkali metal salts of carboxymethylguargalactomannans in sizing from 1 to 25% by weight - based on the dry weight of the yarn -. be used.

7. Use according to one of claims 1 to 6, characterized in that the alkali salts of carboxymethylguargalactomannans are used for sizing yarns made of cotton, regenerated cellulose and mixtures thereof with polyester.

8. Use according to one of claims 1 to 7, characterized in that the sodium salts of carboxymethylguargalactomannans are used.

9. A process for sizing natural and / or synthetic yarns in a known manner with alkali metal salts of carboxymethylguargalaktoman- nans, characterized in that alkali metal salts of carboxymethylguarga lactamannans are used with degrees of substitution below 0.15.