US2101696A - Process for producing two-color effects on skins or furs - Google Patents

Description

Patented, 7, 1937 UNITE- STAT ES- PATENT OFFICE T 2,101,696 I r t raocass roa raonucmo Two-coma EFFECTS ON SKINS OR FURS Heinrich Wagneniiiannheim, and Max Zabel and Alfred Ensslin, Dessa assignors to General 11 in Anhalt. Germany, Aniline Works, Inc., New

York, N. Y., a corporation of Delaware 4 Claims.

Our present invention relates to a process for Y dyeing skins or furs and more particularly to such a process which produces beautiful and permanent two-color effects on the said materials.-

One of the objects of our invention comprises the pretreatment of the skins and furs which are to be dyed in two-color effects. Another object is'a method for producing pelts having white tips.- v 10 Further objects of our invention may be seen from the detailed specification following hereafter.

White-tipped furs have been produced essentially by either of tWomethods. By one of these 1d the fur is treated in a solution of a lead salt and then in a solution of alkali sulfide or polysulfide whereby, according to conditions, brown or black lead sulphide is precipitated on the hair of the pelt. To produce the white tips the pelt is super- 20. ficially painted with an acid solution of hydrogen peroxide which bleaches. the lead sulfide to lead sulfate. By the other method, to the parts of the pelt which are to remain white there is applied by means of a coarse or fine brush a certain.

paraiiin mixture in moltenv condition and then the pelt is mordanted in the usual manner and dyed with an oxidation dye. The paraflin reserve is then removed by means of warm water.

Now we have found that beautiful white and 30, variegated effects can be produced on skins and furs by a specific pretreatment of these materials before dyeing. This pretreatment comprises the following procedure:-

The pelt which has'been softened and killed 36 in the usual manner, is treated with a chromium mordant- Then a solution of an alkali metal carbonate or bisulfite, which may be thickened if desired, is applied to the pelt in order to remove the mordant at the tips or certain spots.

40 After the material has been thoroughly rinsed,

it is immersed in a bath of an oxidation dye which does not dye the tips or spots thus treated, or dyes them in a color other than that of the hair still containing the chromium mordant. These white or variegated effects can be improved by a reducing bleaching bath. i,

As compared with the lead sulfide method associated with the danger of poisoning by lead Application November 26, 1935, Se-

Germany December 15,

there is the advantage of a simpler operation,- more easily applicable in practice.

The following example illustrates the inven-' tion:

An unshorn lambskin is killed in a solution 6 containing per liter 3 grams of calcined sodium carbonate and 5 cc. of ammonia solution of24 per cent. strength for 2 hours at a temperature of 24 C. and is then rinsed in the usual manner and freed from adhering alkali in an acid 10 bath. The skin thus treated is laid overnight in a bath containing per liter 2 grams of potassium bichromate, 0.5 gram of tartaric acid .and. grams of common salt. It is then centrifuged, stretched and painted on the places to .15-

be reserved .with a'solution, .containing per liter, 100 grams of calcined sodium carbonate, 50 grams oi potato starch and 20 grams of a fiber protective agent descdibed in German Patent No. 480,898, this solution being applied with a brush. 2o After several hours the skin is carefully. rinsed; to remove the paste and dyed in a bath of the following composition per liter: 2 grams of a mixture of 40 parts of the compound made by dissolving 1 mol. 2.7-dihydroxy-naphthalene and 255 2 mols 3-chloro-lA-diaminobenzene in alcohol and evaporating the solvent, 60 parts of a dispersing agent and 2 cc. of hydrogen peroxide of 30 per cent. strength, the liquor ratio being 1:750. After dyeing for 20 minutes at'28 0., the skin is 30 removed, carefully rinsed and bleached for a. quarter of anfhour in a bath containing, per liter, 3 grams of zinc salt of formaldehyde-sulfoxylate and 1 cc. of acetic acid of 30 .per cent. strength.

white tips. 4

If instead of the oxidation dye prescribed above there is used the analogous product from 1 mol. LS-dihydroxynaphthalene and '1 mol. meta- The products enumerated in Table B likewise.

yield twocolor effects with a. coloration of the tips or spots other than that of the parts still containing the mordant.

In these tables certain of the dyeing materials (marked by brackets) do not constitute mixtures; i

There is obtained a deep grey-brown ground with 35 toluenediamine there is obtained, by the same 407 Table A Coloration oi- Dye preparation The tips The imor spots respectively 1 2.6-dihydroxynaphthalene +4-eminodi hen lamin p MmoL) Grey White +1.4-dieminobenzene 2 2.6-dihydroxynephthalene +4-aminodi henylamin e P mom Gre White +chl0ro-4-emlnodiphenyiamine (14 3 3 2.7-dihydroxyna hthelene +4-aminodip enylamine Grey White LS-diaminonephthalene 4 2.7-dihydroxynephthale11ie 1) mo +2-chl0r0-lA-diemino enzene Grey i (2 moi.)

5 2.7-dihydroxy'na hthalene +2-chloi-o'1. obenzene 5 2.7-dihydroxynaphthalene +3.5-diemino-4-methoxy- Brown White l-rnethylbenzene 7 .2.7-dihydroxynepl thalene +1-methyl-2A-diamino- Brown White benzene g zJ-dinydroxynaphthalene +8-aminoquinoiine whlte 9 2.5-dihydroxynaphthalene +3.5-d1amino-4-chlor-l- Brown White 'methylbenzene 10 3.5.8.10-tetrahydropyrene K +2.6-diaminonaphthalene known white 2 11 Lfi-dihydroxynaphthalene +8-aminoquinoline White 12 2.6-dihydroxynaphthelene +1.5-dieminonaphthelene m 13 Lfi-dihydroxyne. hthalene +benzidine p P 14 1.5-dihydroxynaphthalene +l.5-diaminonaphthalene' white 5 1.5-dihydroxynaphtheierie +2-emino-1-(dimethylemi- Red White no)-benzene 16 Lb-dihydrexyna hthslene +4-am1nodip enylamine-Zi- Violet-brown White sulfonic acid 17 LG-dihyglroxynaphthalene I +1-(dimethylammo)-2-chlor- Violet-brown White 4-aminobenzene 18 1.7-dihydroxynaphthalene 1.3 dieminobenzene or i Black-brown White methyl-ZA-diaminmbenzene 19 LB-dihydroxyneplrthaiene +2-dimethylammo-4-amino- Red-brown White l-chlorobenzene 20 1.4-dihydroxybenzene-2-phena ylsulione-hlA-diaminoben- Red-brown White zene 21 Dimethylgallic acid Beige White 22 l.3-dihydroxybenzene+2.2'-dlamino-LY-dinaphthyl white Table B Coloration oi- Dye preparation The ups The fur spots tospectlvely 1 1.5 dih droxynaphthalene ZA-dieZIlnQ-I-nitwbenzene Yellow 2 1.6-dihydroxynephthelene+2 nitro-li-dimethyleminoquln- Brown-olive Yellow oline 3 1.5-dihydroxynaphthelene+lamino-2-dimethylamlno-4- Red-brown Yellow nitrobenzene 4 1.6-dihydroxynaphthelene+lamino 2- dimethylemino 4 Brown Yellow nitrobenzene -5 1.5-dihydroxynephthelene-l-4- amino-l-(methylethylemino)- }Dark-biue Light-blue benzene v 6 1.6-dihydroxynaphthalene-l-lmethylamino 2 ehloro 4 Dark-violet Light-violet eminobenzene 7 2.6-dihydroxynaphthalene 1) mo +1-(dimetl1ylemino)-4-amino- Datk'gmm Llzm'mn benzene a 2.7-dihydroxynaphthalene 2- amino4.6-dinitro-4'-(dimeth- Brown Pink y1amino)-diphenylemine 9 1.6-d1'hydroxynaphthalene 4- amino-2-chloro-l -(di1nethyl- Violet-brown Pink nmino)benzene 10 1.5 dihydroxynaphthalene 1.3 3 di (dimethy1amino)- 4 Brown Light-red eminobenzene Y 11 2.7 dihydroxynephthelene 2.4.9- triamino--i- (dimethyl- Brown Violet a1n1no)-diphenylamine l2 3.5.8.10-tetrahydroxypyrene i-aminodiphenylemine Gm From the example and from the tables it may be seen that many of pelt dyes are suitable for producing the two-color efiects on the pelts pretreated according to our invention. It is obvious, however, that our invention is not limited to these specific dyes, and other oxidation dyes suitable for the same purpose are considered to be within the scope of the claims following hereafter.

What we claim is:--

1. The process which comprises treating a fur or pelt in a chromium modanting bath, tipping or spotting the mordanted hairs with an agent of the group consisting of alkali metal carbonate and alkali metal bisulfite for removing the mordant, rinsing the pelt and dyeing it with an oxidation dye yielding difierent colorations on the mordanted and unmordanted places.

2. The process which comprises treating a fur or pelt in a chromium mordanting bath, tipping or spotting the mordanted hairs with an agent of the group consisting of alkali metal carbonate and alkali metal bisulfite for removing the mordant, rinsing the pelt and dyeing it with an oxidation dye which dyes only the mordanted parts of the pelt.

3. The process which comprises treating a fur or pelt in a chromium mordanting bath, tipping or spotting the mordanted hairs with an agent of the group consisting or alkali metal carbonate and alkali metal bisulfite for removing the mordant, rinsing the pelt, dyeing it with an oxidation dye which dyes only the mordanted parts of the pelt, and subjecting it to a reducing bath;

4. The process which comprises mordanting a fur or pelt with an alkali metal blchromate, tipping of spotting it with a. thickened solution containing an alkali metal carbonate and thus re moving the mordant, rinsing it and then dye-.

ing it in an aqueous solution containing an oxidizing agent with the product, obtainable by dissolving "one. molecular part of 2.7-dihydroxynaphthalene and two molecular parts of 3-ch10- ro-lA-diaminobenzene in alcohol and 1 evaporating the solvent, rinsing the dye thus colored in two-color effects and finally subjecting it to a.

reducing bleach.

HEINRICH WAGNER.

MAX ZABEL. ALFRED ENSSLIN.