formaldehyde - Sciencemadness Dot Org

USES OF FORMALDEHYDE 355
23. Kodak Ltd., British Patent 539,703 :i941X
24. Lumiere, L.s and Seyeweta, A., Bull Soc. Clint., 15, sis* t553>.
25. Lumiere, L., and Seyewstz, A., J/ontf. Seient., 17.109 '1903).
26. A. Lumfere et ses Fila, French Patent 324,921 1902;.
37. Liittke, HM and Arndt, P., British.Patent-23,729 ;i904;; French Patent 347 395 1904
28. Mackler, A. L, TJ. S. Patent 2,053,521 (t&BB).
2S. Merckecs, W.t German Patent 301,391 (1919).
30. Monekhoven, D. van, Bull. Beige., 6,17S US79); Phot. Korr., 16, 2GS • 1*73;.
31. MueHer,L. B„ (to Eastman Kodak Co.),U. S. Patent 1,557,515 (1332;.
32. Muehlar, L. E., (to Eastman Kodak Co.), L". S. Patent 2:18i,053 1939\
33. Newens, F. R., "Colour Photography," p. «, London, Blackie and Son Ltd., 193^; Wall, E. J., "Pilots
graphic Facts and Formulas/ p. 240-1, Boston, American Photographic Publishing Co 104D
34. Paris, L. F., French Patent 763,085 (1934).
35. Penitz, O., Phot. Ind., 1931. 1131.
36. Roth, C. A., (to Powers Photo Engraving Co.), V. S. Patent 1,496,325 Cmi't.
37. Schneider, W., (to Agfa Ansco Corp.) IT. S. Patent 2,150,734 (1940].
SS. Sehwarta, A. F. Y., and Mercklin, F. H., British Patent 741/1889.
39. Sheppard, S. E., and Honck, &. C, (to Eastman Kodak Co.), TL S. Patent 2,056,817 .'1936); (bo Kodak
Ltd.), British Patent 463,427 (1937).
40. Sheppard,S.E.)andHouok,H.a, (Eastman Kodak Co.), U. S. Patent2,lSS,774 ri933>; (to Kodak Ltd. 1,
British Patent 479,419 (1638).
41. Sheppard, S. E., and Houck, R. C, (to Kodak Ltd.), British Patent 50*,37S (1939).
42. Snyder, F. H., and Rimbach, H. W-, (toTechnics, Inc.), U. S. Patents 2,171,609 '1939) and 2,231,201 UM1).
43. Stewart, V. A., U- S. Patent 1,569,151 (1926).
44. Stewart, V. A., (to- Louis A. Solomon), U. S. Patent 1,907,269 {19351.
45. Willcock, H. B., British J. Phot., 1931, 195 (March).
Rubber
Formaldehyde is used in connection with the handling of rubber latex*
the production of crude rubber, the modification of rubber for special purposes
and the synthesis of rubber accelerators and antioxidants. It may
also find applications in the production of synthetic rubber and rubber
substitutes.
Rubber Latex. Small quantities of formaldehyde (0.1 to 1 per cent)
are sometimes added to rubber latex for the purpose of preventing putrefaction
of its protein constituents 33 . Unfortunately however, formaldehyde-preserved
latex thickens after a short time and cannot be shipped.
Ammonia, which is commonly used as a latex preservative, is an excellent
anti-coagulant but is said to be inferior to formaldehyde in that the rubber
obtained from ammonia-preserved latex shows a higher degree of water
adsorption. According to McGavack 17 , the advantageous properties of
both agents can be obtained by adding ammonia to formaldehyde-preserved
latex which has been allowed to stand for approximately 24 hours
and consequently contains substantially little free formaldehyde. It is
reported that latex preserved in this way will withstand shipment and on
coagulation yields an improved rubber of low water absorption. The latter
property is believed to be a result of the insolubilizing action of formaldehyde
on the rubber protein. Rubber obtained from formaldehyde-preserved
latex is also reported 18 to have a good resistance to oxidation since
it retains a high proportion of the natural antioxidants present in the latex.