US2129854A - Manufacture of leather - Google Patents

Description

Patented Sept. 13, 1938 MANUFACTURE OF LEATHER Gustav Mauthe and Hermann Noerr, Leverkusen- I. G. Werk, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-:01:- the-Main, Germany No Drawing. Application November 21, 1935, Se-

rial No. 50,989. In Germany November 28,

9 Claims. (Cl. 1495) agents display some properties which impair nuclei in asimilar manner, the effect is dependent their value. For example, after the usual rinson the constitution. The simple sulphonic acids ing, greasing and drying, they exhibit a rather of benzene and naphthalene show a relatively hard feel. Although this is somewhat improved small, although noticeable e c W ch esults by subsequent staking, even then the finished in a somewhat softer feel and an improvement in 10 leather still leaves much to be desired in this rethe fullness of the leather. A considerable inm spect. A further disadvantage consists in the crease of the efficacy is attained y r pl cin the fact that the color of the finished zirconiumsimple sulphonic acids by, for example, substitanned leathers has a somewhat yellowish shade tuted triphenylmethane sulphonic acids, such for which can be noticed even if pure zirconium cominstance as tetrachloro-dihydroxyp y pounds have been employed and if the leathers methane sulphonic acids. 15 have been greased with light-coloured water- The treatment may be preformed in various soluble oils. ways and at various stages of the tannage. It

In accordance with our invention, these diss po s for instance. to p oy t e said comadvantages can be diminished or practically Pounds in the Place Of the usual neutralizing completely overcome. agents such as sodium bicarbonate; they may 20 The process of this invention comprises the step o be a d to the tanning liquor q ent ofacting on the leathers, during or after tanto neutralization. A further possibility consists nage, with non-tanning water soluble sulphonic in the after-treatment of the tanned leathers in a or carboxylic acids containing aromatic nuclei or f es b t before after the usual rinsing water-solublesalts of such sulphonic or carboxpr Even small amounts f the aromatic 25 ylic acids By the term non-tanning, as used comp s e fi c t, and they may be cmabove and in the appended claims, such comployed as such or in admixture with one another; pounds are meant which, when used alone, are on an average there is employed about 0.5 to 5% not capable of converting the animal skin into ca d on the We t o e hides.

3o leather. According to a further feature of our In a c s the treatment results in n 80 invention the said improvement becomes still proved takin p f fat n n mpr vement in more obvious if such aromatic compounds are the qu y of the leather s regards color, softused the molecular Weight of which has been ness, fullness or feel. increased either by linkage of several nuclei or The following p s ate t e invention 5 by substitution, for instance, by hydroxyl groups without limiting it thereto, the indications in or chlorine. per cent being calculated on the Weight of the For instance, whereas the effect with benzoic hides:- Example 1 acid is still rather small, the use even of dichlorobenzoic acid results in an evident improvement in Pickled Calf hides are treated With an aqueous 4n the leather quality as regards fullness and color. on o sodium chloride and co ium sul- A similar good result is obtained by substituting ohate until y are l struck hrou h. The into the molecule an aromatic nucleus, for inleather thus prepared is treated for One to two stance a benzoyl residue. A considerable 1 hours in the drum with 100% of water and 5% provement can be attained by the application of Of the sodium salt Of naphthalene -d u compounds containing hydroxyl groups h as phonic acid. The leather is then well rinsed, 5 chlorohydroxybenzoic acid. The aromatic digreased, dried, Stretched and e A White carboxylic acids display a similar behaviour. leather of improved ss and outstandin Whereas, for example, the efiect obtained by usfastness to i t is Obtaineding phthalic acid is not yet sufficient for all prac- Example 2 tical purposes, dichloroor tetrachlorophthalic 5 acids prove themselves to be excellent auxiliary Pickled calf hides are treated in accordance agents, as besides effecting an improvement in with the directions given in Example 1, the socolor, softness, grain and resisting capacity todium salt of naphthalene 1.5-disulphonic acid wards hot water, they yield leathers which are being replaced by the same amount of the sodium 5 absolutely fast to light. Here too the more comsalt of 2.2-dihydroxy-3.5.3.5'-tetrachloro-tri- This invention relates to improvements in the manufacture of leather.

, Minerally tanned leathers prepared with the aid of water soluble zirconium salts as tanning plicated compounds, for example those possessing two nuclei in the molecule, such as terephthalylbenzoic acid, display an outstanding efiect.

With the sulphonic acids containing aromatic phenylmethane 2" sulphonic acid. By this treatment the softness and the whiteness of the leather are still more improved than by the treatment in accordance with the manner described in Example 1.

Example 3 Example 4 A treatment is performed in accordance with the directions given in Example 3, replacing the dichlorophthalic acid by terephthalyl-2-benzoic acid. Fullness, softness, feel and the resisting capacity towards hot water are considerably improved in comparison with non-after-treated zirconium sulphate-tanned leathers; the fastness to light is scarcely less than that of the product prepared in the manner described in Example 3.

Example 5 A calf hide tanned with zirconium sulphate is after-treated with 5% of the sodium salt of 2.5- dichlorobenzoic acid in 100% of water, whereby, after rinsing, greasing and drying, an improvement in the fullness and softness of the leather is obtained.

' Example 6 Instead of the sodium salt of dichlorobenzoic acid mentioned in Example 5 the sodium salt of 4-chlorobenzoyl-2-benzoic acid can be employed with the same success.

Example 7 The dichlorobenzoic acid salt of Example 5 is replaced by the same amount of 5-chloro-2-hydroxybenzoic acid. Besides improved fullness, a finer white and a greater resisting capacity towards hot water is attained.

Example 8 A piece of goat hide which has been tanned with 8% of sodium sulphate and 2.5% of zirconium dioxide (as ZrOC12.8H2O) in 100% of water is after-treated.for two hours in a fresh bath to which 2% of a mixture of the sodium salts of the dichloro and tetrachloro-phthalic acids are added. The hide is then thoroughly rinsed, greased with a light-coloured water-soluble oil and pole-dried. Whereas a hide which has not been treated in accordance with the process of this example and which has only been rinsed, greased and dried, shrinks very much and is hard after drying, the after-treated leather is much softer and fuller and possesses an excellent fastness to light.

Eaample 9 A goat hide tanned with zirconium oxychloride a non-after-treated leather to those pointed out in Example 8.

We claim: a

1. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a non-tanning compound containing an aromatic nucleus selected from the group consisting of watersoluble carboxylic and sulphonic acids and watersoluble salts of carboxylic and sulphonic acids.

2. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a non-tanning compound according to claim 1, in which compound the aromatic nucleus contains a substituent group.

3. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a non-tanning compound according to claim 1, which compound contains more than one aromatic nucleus- 4. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a non-tanning compound according to claim 1, which compound contains more than one aromatic nucleus and in which compound the aromatic nucleus contains a substituent group. I 5. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a non-tanning watersoluble halogenated aromatic acid, which may be present in the form of a watersoluble salt.

6. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solu tion having incorporated therein a non-tanning watersoluble halogenated aromatic carboxylic acid, which may be present in the form of a watersoluble salt.

7. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a watersoluble salt of a chlorophthalic acid.

8. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a watersoluble salt of tetrachlorophthalic acid.

9. In the process of tanning with zirconium salts, the modification which comprises applying to the leather, during or after tannage, a solution having incorporated therein a mixture containing alkali salts of di-, triand tetrachlorophthalic acids.

GUSTAV MAUTHE. HERMANN NOERR.