US2129554A

US2129554A - Tanning material

Info

Publication number: US2129554A
Application number: US172043A
Authority: US
Inventors: Russell Alfred; John W Copenhaver
Original assignee: Rohm and Haas Co
Current assignee: Rohm and Haas Co
Priority date: 1937-10-30
Filing date: 1937-10-30
Publication date: 1938-09-06
Anticipated expiration: 1955-09-06

Description

Patented Sept. 6, 1938 UNITED Y STATES .TANNING MATERIAL 1;

" Alfred Russell and John w. Copenhayer, rundelphia, Pa., assignors to Rohm & Haas Company, Philadelphia, Pa.

No'Drawlng. Application October so, 1937,

Serial No. 172.043

, 12 Claims. (Ci. 149-5) This invention relates to the production of,

new synthetic taiming materials that may be used in tanning skins, to retan leather made with other tanning materials, and to bleach and brighten chrome leather.

- In our copending application Serial No. 161,066 filed August 26, 1937, it is shown that-excellent tanning materials especially useful for bleaching chrome leather can be made by condensing a dihydroxydiaryl sulfone sulfonate with formaldehyde. In copending application, Serial-No. 172,042, filed on even date herewith, it is shown that the tanning and bleaching properties of these sulfone sulfonate-formaldehyde condenlfi sates can be improved by co-condensing urea and the sulfone-sulfonate with formaldehyde. We have also found that a similar improvement is obtainable if instead of starting with the sulfonated dihydroxy diaryl -sulfone the unsulfon- 30 ated material is reacted with'urea and formaldehyde and the resulting water insoluble condensate dispersed in an aqueous solution of an aromatic sulfonic acid, such as naphthalene sulfonic acid.. When applied tothe bleaching the 35 chrome tanned leather'these materialsgive a rapid and intensive surface retannage and an improved quality white leather that has a remarkable resistance to sunlight. In making the condensate the reaction is car- ;0 ried out on the wild side of neutrality, preferably in concentrated hydrochloric acid or sulfuric acidof equivalent strength. The dihydroxy diarysulfone and urea may be dissolved in a strong aqueous. solution of acid, the solution ;5 heated to a temperature at which. formaldehyde condenses readily with the sulfone and the urea, and the formaldehyde added slowly while the mixture is being vigorously stirred. After all the formaldehyde is added, heating at the to boiling point of the solution with reflux of vaporized material is continued until reaction is complete. If desired, the formaldehyde may be added to the cold solution of the sulfone and urea...

The relative proportion of urea, sulfone and formaldehyde that may be used varies over a wide range. The best ratio we have found is two molecular equivalents each of formaldehyde and sulfoneto one molecular equivalent of urea.

These ratios webelieve give on condensation a molecule having the formula wherein the'Bs are similar or dissimilar dih i5 droxy diaryl sulfone groups attached to the methylene groups by nuclear carbon atoms. Reducing the quantity of urea reduces the amount of this material in the final condensate and accordingly while permissible is not recommended. The formaldehyde maylikewise be reduced, par- 6 ticularly if less than the above stated amount, of urea is used. However, there-should be used one mol. of formaldehydio'r each two mols of sulfone plus one mol. of iormaldehyde for each mol.. or urea. Increasing the ratio of urea and 10 formaldehyde leads to the formation of more complicated molecules but up to four mols of formaldehyde and up to two mols of urea to two mols of sulfone may be used.

The tanning solution is prepared by adding the desired amount of the water insoluble conden-v sate to an aqueous solution of naphthalene sulfonic acid and vigorously stirring, preferably while heating the mixture. Heating to aid dispersion of the condensate is unnecessary but subventiom- In these examples the parts given are so parts by weight.

Example 1.50 parts of 4:4 dihydroxy diphenyl sulfone was suspended in 300 parts of 36% aqueous hydrochloric acid containing 6 parts of urea and the suspension heated with vigorous stirring to 98-400 C. 20 parts of 30% aqueous formaldehyde was added slowly over 5 minutes and the whole maintained at a temperature of 98-100 C. under reflux with vigorous stirring for 2 hours. At this time aninsoluble resin had separated. It was removed from the aqueous layer, washed twice with boiling water, and dried. 25 parts of this resinous material was added to a solution of parts naphthalene sulfonic acid in 20 parts of water and the mixture heated with 4,5 brisk stirring at C. until complete solution was obtained and the product was stable to indefinite dilution with water. The reaction mixture was diluted to a final mass of 200 parts with water. This solution may be used directly for 50 tanning or it may, if so desired, be partially neutralized with alkali first and then applied to tanning. I

Example2.--50 parts of 4:4 dihydroxydi phenyl sulfone was suspended in a solution of 100 parts 98% sulfuric acid dissolved in 175 parts of water containing 6 parts of urea. ,The suspension was heated to the boiling temperature 'under reflux and 20 parts of 30% aqueous formaldehyde added. The whole was maintained at the boiling temperature for 2 hours. At the end of this time the precipitated resin was collected, washed twice with boiling water, dried, and dispersed in a solution of naphthalene sulfonic acid and water using the quantities and method described in Example 1.

The dihydroxy diphenyl sulfone used in these I examples can be replaced with equivalent quantities of other dihydroxy diaryl sulfones such as a pH of 4-4 when it may be oiled and finished in any recognized manner. The leather so produced has a white surface of remarkable resistance to the action of strong sunlight.

. We claim:

l. The process of preparing a synthetic tanning material which comprises co-condensing a dihydroxy diaryl sulfone and urea with formaldehyde in strong acid solution and dispersing the resinous material obtained in an aqueous solution of an aromatic sulfonic acid.

2. The process of preparing a synthetic tanning material which comprises co-condensing a dihydroxy diphenyl sulfone and urea with formaldehyde in strong acid solution and dispersing the resinous material obtained in an aqueous sotion of an aromatic sulfonic acid.

3. The process of preparing a synthetic tanning material which comprises co-condensing 4:4 dihydroxy diphenyl sulfone and urea with formaldehyde in strong acid solution and dispersing the resinous material obtained in an aqueous solution of naphthalene sulfonic acid.

4. The process of preparing a synthetic tanning material which comprises co-condensing substantially two molecular equivalents of a dihydroxy diphenyl sulfone and substantially one molecular equivalent of urea with substantially two molecular equivalents of formaldehyde and dispersing the resinous material obtained in an aqueous solution of an aromatic sulfonic acid.

5. The process of preparing a synthetic tanning material which comprises co-condensing substantially-two molecular equivalents of a dihydroxy diphenyl sulfone and substantially one molecular equivalent of urea with substantially two molecular equivalents of formaldehyde and dispersing the resinous material obtained in an aqueous solution of naphthalene sulfonic acid.

6. A synthetic tanning material which is a joint condensation product of a dihydroxy diaryl sulfone and urea with formaldehyde dispersed in an aqueous solution of an aromatic sulfonic acid.

'7. A synthetic tanning material which is a Joint condensation product of a'dihydroxy diaryl sulfone and 'urea. with formaldehyde dispersed in an aqueous solution of naphthalene sulfonic acid.

8'. A synthetic tanning material which is a joint condensation product of 4:4 dihydroxy diphenyl sulfone and urea with formaldehyde dispersed in an aqueous solution of naphthalene sulfonic acid.

9. A synthetic tanning material which is a joint condensation product of substantially two molecular equivalents of a dihydroxy diphenyl sulfone and substantially one molecular equivalent of urea with substantially two molecular equivalents of formaldehyde dispersed in an aqueous solution of an aromatic sulfonic acid.

10. A synthetic tanning material which is a joint condensation product of substantially two molecular equivalents of a dihydroxy diphenyl sulfone and substantially one molecular equivalent of urea with substantially two molecular equivalents of formaldehyde dispersed in an aqueous solution of naphthalene sulfonic acid.

11. In a process of making leather the improvement which comprises treating a chrome tanned leather with a joint condensation product of a dihydroxy diphenyl sulfone, urea and-formaldehyde dispersed in an aqueous solution of naphthalene sulfonic acid.

12. In a process of making leather the improvement which comprises treating a chrome tanned leather with a joint condensation product of substantially two molecular equivalents of a dihydroxy diphenyl sulfone, substantially one molecular equivalent of urea, and substantially two molecular equivalents of formaldehyde dispersed in an aqueous solution of naphthalene sulfonic acid.

- ALFRED RUSSELL.

JOHN W. COPENHAVER.

I CERTIFICATE OF- CORRECTION. 7 Patent No, 2,129,55L September 6,19 8.

' ALFRED RUSSELL, ET AL. I

It is hereby certified that-error appears in the printed specification of the above numbered patent requiring correction as follows:. Page 1, first column, line 2h, for the article "the" second occurrence, read of; line 55, for "diarysulfone" readdiarylsulfone; and second column,'line 10, for "'or' read of; page Z, first column, line claim 2,'for the syllable and words "tion of an aromatic" read lution of naphthalene; and that the said Letters Patent shonld be'read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 10th day of January, A. D. 1959.