DE3141496A1 - POLYMER TANNING MATERIAL AND METHOD FOR TELLING BACK - Google Patents

Description

'""' '3ΗΗ96

BASF Aktiengesellschaft "^" 0.2.0050 / 35505

"polymeric tanning agent and process for retanning

The main tanning is usually done with mineral tanning agents such as basic chromium, aluminum and / or zirconium salts alone or in combination with synthetic tanning agents carried out. A subsequent retanning with natural or synthetic tanning agents are used to improve Leather properties such as handle, softness, grain texture and abundance. Syntans, water-soluble condensation products from z. B. naphthalenesulfonic acid and formaldehyde or from phenolsulphonic acid, formaldehyde and urea, furthermore ligninsulphonic acids and for some years now Polymers and copolymers based on acrylic acid and

IS other unsaturated polymerizable carboxylic acids, in usually used in combination with the aforementioned syntans. They all have an anionic character, which means the colorations can be lightened to a greater or lesser extent with the usual anionic dyes.

From DE-OS 28 43 233 it is known that low molecular weight Condensation products with cationic groups when used alone in retanning the dyeing properties improve the leather in the above sense. When combined with the usual anionic condensation or However, polymerization products largely lose this ability.

The invention was therefore based on the object of providing a copolymer to develop that both when used alone and in combination with the otherwise common anionic Condensation products (syntans) and polymers the coloring properties in the sense of a lower shade lightening improved when using anionic dyes.

u · ^J

3ΗΪ496

BASF Aktiengesellschaft - ^ - - 2> - 0.2 ^ 050/35505

This object is achieved in the copolymer according to claim 1.

The copolymer contains 20 to 80, preferably 40 to 60 wt.% · * Acrylamide or methacrylamide and 80 to 20, preferably 60 to 40 parts by weight in each case based 5S ₉ containing on the polymer, of an amino group, copolymerizable monomers in aqueous solution ( Component b of claim 1).
10

As component a, acrylamide is preferred over methacrylamide.

For example, the methacrylic esters and preferably the acrylic esters of diethylamino- or, preferably, dimethylamino-ethanol, -propanol or -2,2- -dimethylpropanol come into consideration as component b. Dimethylaminoethyl acrylate. · In addition, it is preferable are amino Cp_ _t --alkyl (meth) acrylamides such as N- (3-Dimethylaminopropy1) methacrylamide, very suitable.

As component c are for example: acrylonitrile, Vinyl pyrrolidone, acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid. Vinyl pyrrolidone is preferred and acrylic acid. They are used in amounts of 0 to 20, preferably 0 to 5 wt .- /? polymerized. the Polymerization is carried out in the usual way (as described, for example, in Ulimann, Enzyclopadie der technischen Chemie, Edition, Volume 19, for example on pages 3 et seq. And 385 et seq. Is described) in aqueous solution after the radical Mechanism carried out.

The K values (see FIG. H. Pikentscher, Cellulose-Chemie 13, 1932, pages 58 to 64 and 71 to 74), measured in one percent neutral aqueous solution at 20 ⁰ C, to the

3UU96

BASF Aktiengesellschaft - * - 4 "- ^α 2.0050 / 35505

• range from 20 to 150, preferably 20 to 130. For the improvement of the dyeing properties are in particular products with K values of 50 to 130, for the improvement the fullness and softness those with K values of 20 to 80, preferably 20 to 50, are suitable To improve both, it is expedient to use a polymer with a very broad molecular weight range or else two polymers with different molecular weights at the same time or one after the other.

The copolymers to be used according to the invention are in the usual way by polymerization in aqueous or organic solution or in dispersion with the usual free radicals Starters (e.g. peroxides, azodiisobutyronitrile

lg etc.). They can be used alone, but preferably together with other conventional retanning agents of the type mentioned at the outset. The amount used is 0.025 to 1, preferably 0.1 to 0.4 weight-5%, based on the shaved weight. If the primary aim is to improve body and softness, relatively large amounts (0.2 to 1, preferably 0.3 to 0.4 %) are required. To improve the dyeing properties , for example in the case of leather retanned with an anionic tanning agent, quantities in the lower range mentioned, that is to say 0.025 to 0.2 %, are sufficient.

The retanning according to the invention is timed between the main mineral tanning and dyeing of the leather. She can be self-employed separately Operation or together with the greasing. As I said, it is possible and even preferred to have them with one to combine conventional retanning, i.e. with anionic retanning agents, or to add them to it.

BASF Aktiengesellschaft _ y _ £ _ O.2.OO5O / 355O5

Despite the color-deepening effect, the colorations are evenly. In addition to deepening the color, the dye is better fixed so that migration occurs on drying no longer occurs. The polymer can also be used after coloring, especially for this last-mentioned purpose will. If the dyebath has not yet been emptied, the liquor must be changed, otherwise it will be included Precipitation is to be expected.

Since every leather treatment according to the invention with a certain (more or less strong) retanning effect have been included in the title and in the main claim for the sake of simplicity all measures mentioned are summarized under the term "retanning", although sometimes the improvement of the dyeing Behavior is paramount.

The liquor length in the conventional as well as in the retanning according to the invention is from 30 to 300, preferably from 100 to 150 % _9, based on the shaved weight. The temperature is generally from 20 to 60, preferably from 30 to 40 ° C., the pH is from 3 to 6, preferably from 3.5 to 5, and the treatment time is on the order of one to several hours.

The water solubility of the polymers to be used according to the invention decreases with increasing molecular weight. It is intended for the purposes of the invention, among the above, conventional in tanning or retanning conditions (20 to 60 C at pH 3 to 6) at least 2, preferably at least 10 wt -.% Amount. 10% strength by weight aqueous solutions of the polymers are generally still easy to pour. The polymer does not necessarily have to be completely real (clear) in solution (although this is preferred); a colloidal (ie more or less cloudy) solution is also sufficient.

BASF Aktiengesellschaft - / - Q _ O. Z. 0050/35505

^ The parts and percentages given in the examples relate to the weight, namely. Unless otherwise stated or unless the context indicates otherwise, to the shaved weight.
5

The starting materials mentioned in the examples, apart from the polymer tanning agent according to the invention, are commercially available.

example 1
10

Post-treatment of chrome-tanned, folded small animal skins

Neutralization:

100% water 4O ⁰ C
1 % sodium formate
1 % sodium bicarbonate
Move for 30 minutes, remove the liquor.
20th

Retanning:

100 % water 4o ° C

4 % of a 10% aqueous solution of a copolymer with a K value of 35, consisting of 50 % acrylamide, 10 % vinylpyrrolidone and 40 % dimethylaninoethyl acrylate. Move for 90 min

Drain the liquor.

Coloring / greasing:

100 % water 60 ° C

1 % of an anionic dye
Move for 30 min
+ 4 % of a commercially available anionic fatliquor

3U1496

BASF Aktiengesellschaft _ ^ - Zf ^ O.2.OO5O / 355O5

Based on a sulfited and oxidized maturing oil (possible alternative: the same amount of a sulfochlorinated and partially saponified chlorinated paraffin) stir for 30 to 60 minutes
+0.5 to 1 % formic acid 80%
Move for 30 min

Drain the liquor, rinse and dry the leather.

The result is a leather of medium fullness with an elastic handle, whose coloring with anionic dyes is much more intense and turns out to be more brilliant than after treatment with commercially available anionic retanning agents, including according to DE-OS 28 43 233.

Example 2

Retanning of chrome-tanned, folded cowhide or calf leather

Neutralization:

200 % water 40 ° C
1% sodium formate

O ₃ 5 % of a commercially available neutralized condensation product of a phenol or naphthalenesulfonic acid

with formaldehyde
Move for 60 min

Drain the liquor, rinse.

Retanning:

100 % water 40 ° C

Move 3 % of a 40% aqueous solution of a copolymer with a K value of 30 made from 70 % acrylic acid and 30 % acrylonitrile for 30 minutes

BASF Aktiengesellschaft - ^ - g_ O.Z.0050 / 35505

^r + 2 % of a 10% aqueous solution of a copolymer consisting of 60 % acrylamide and 40 % dimethylamine »- ethyl acrylate with a K value of 53
Move for 50 min
+ 4 % of a commercially available synthetic tanning agent

Based on a phenol sulfonic acid-phenol-formaldehyde condensate
Move for 30 minutes, remove the liquor.

Coloring / greasing: as in example 1

It is compared to a similar one, but without any use the polymer solution with or without a retanning agent according to DE-OS 28 43 233 made a noticeable leather Soft, deeper and more brilliantly colored leather is obtained.

Example 3

As in Example 2 with a 10% aqueous polymer solution of 75 % methacrylamide, 5 % methacrylic acid and 20 % methacrylamidodimethylaminopropylamide with a K value of 135.

The leather obtained shows the same softness and somewhat darker than that obtained according to Example 2 Aniline staining a greater abundance.

BASF Aktiengesellschaft - ^ - - 9 - O.2.OO5O / 355O5

Example 4

Retanning of chrome-tanned, folded cowhide or calf leather
5

Neutralization:

200 % water 40 ° C

1 % sodium formate
IK sodium sulfite

Move for 60 min, drain the liquor, rinse.

Retanning:

150 % water 40 ⁰ C

4 % of a commercially available synthetic tanning agent based on a phenol sulfonic acid-phenol-formaldehyde condensate

Move 2 % of a commercial vegetable extract for 60 minutes

+ 2 % of a 10 ^ aqueous solution of a copolymer consisting of 60 % acrylamide and 40 % dimethylaminoethyl acrylate with a K value of 69

45 min move
Drain the liquor, rinse "

Coloring and greasing according to Example 1.

But it will get compared to a similarly _s without using "Using the polymer solution with or without a retanning according to DE-A 28 43 233 leathers produced a softer, more elastic to the touch leather with significantly deeper color.

BASF Aktiengesellschaft - ^ - - 40 ' 0.2-OO5O / 35505

^r Example 5

Dyeing of anionically retanned cowhide in dark shades

Neutralization:

200% water 4O ⁰ C

Move 2 % of a commercially available, neutralized condensate of naphthalenesulfonic acid with formaldehyde for 60 minutes

+ 5 % of a commercially available synthetic tanning agent based on a phenol sulfonic acid-phenol-formaldehyde condensate + 5 % of a commercially available vegetable extract move for 90 minutes, drain the liquor, rinse.

Coloring / Fatliquoring 200% water 50 ⁰ C

1 % of a 10% aqueous solution of a copolymer consisting of 60 % dimethylaminoethyl acrylate and 40 % acrylamide with a K value move for 40 minutes + 1 % of an anionic dye (aniline dye) move for 20 minutes + 8 % of a 60% fatliquor as in Example 1 Move for 30 min + 0.5 % formic acid 80% Move for 20 min Drain the liquor, rinse, dry.

A leather with a deeper coloration than according to Examples 2 to 4 is obtained, while the handle and fullness of the leather are only in are influenced to a lesser extent.

Claims (3)

3H1496 SASF AHhngwtliehaft O.Z.0050 / 35505 Claims I »Polymer tanning agent, consisting of a copolymer from the K> value according to Fikentscher in the range from 20 to S 150 off a) 20 to 80 wt. Acrylamide or methacrylamide, b) 80 to 20 wt -.% of an amino group-containing acrylate or acrylamide of the general formula H ₂ C = CH-C (O) XA-NR ₂ with
A- C ^ c R s methyl or ethyl and
X = O or NH ₉ c) 0 to 20 wt. another, in aqueous solution copolymerizable monomers. 2. A process for retanning mineral-tanned leather by treating it with an aqueous solution of Oj _1025-1 weight ?, based on shaved weight, of a copolymer according to claim I ₅ at a liquor length, based on shaved weight, of 30 to 300% _s pH values in the range from 3 to 6 and temperatures from 20 to 6O ⁰ C. 3. The method according to claim 2, characterized in that dimethylaminoethyl acrylate or dimethylaminoneopentyl acrylate is used as the amino group-containing monomer (component b). 473 / 8I BR / Ws 10/19/81