Researches on Cellulose Part 6

(16) American Pat. 573132, Dec. 15, 1896.

(17) This proportion is the most advantageous, and furnishes the best liquid collodions that can be spun.

(18) French Pat. 259422, Sept. 3, 1896.

(19) English Pat. 22540, 1896.

(20) Application for German Pat. not granted, 4933 IV. 296, Mar. 16, 1897.

(21) German Pat. 96208, Feb. 10, 1897. Addit. Pat. 101844 and 102573, Dec. 10, 1897.

(22) Oberle et Newbold, French Pat. 25828, July 22, 1896. Granquist, Engl. applic. 2379, Nov. 28, 1899.

(23) German Pat. 72572, June 17, 1891.

(24) Voy. Stern, Ber., 28, ch. 462.

_Group II_

(1) German Pat. 98642, Dec. 1, 1897 (Pauly). French Pat. 286692, March 10, 1899, and addition of October 14, 1899 (Fremery and Urban). French Pat. 286726, March 11, 1899, and addition of December 4, 1899. German Pat. 111313, March 16, 1899 (Fremery and Urban). English Pat. 18884, Sept. 19, 1899 (Bronnert). English Pat. 13331, June 27, 1899 (Consort.

mulhousien).

(2) French Pat. 203741, Feb. 12, 1890.

(3) The actual lapse of this patent is due to the death of Despeissis shortly after it was taken.

(4) Without questioning the good faith of Pauly, it is nevertheless a fact that the original patent remains as a doc.u.ment, and therefore that the value of the Pauly patents is very questionable.

(5) Girard, Ann. Chim. et Phys, 1881 (5), 24, p. 337-384.

_Group III_

(1) Cross and Bevan, Cellulose, 1895, p. 8.

(2) English Pat. 16805, Dec. 22, 1884.

(3) English Pat. 17901, July 30, 1897.

(4) Bronnert, American Pat. 646799, April 3, 1900.

(5) Cross and Bevan, Cellulose, 1895, p. 12.

_Group IV_

(1) English Pat. 8700, 1892. German Pat. 70999, Jan. 13, 1893.

(2) English Pat. 4713, 1896. German Pat. 92590, Nov. 21, 1896.

(3) Comptes rendus (loc. cit.). Berichte, c. 9, 65a.

(4) English Pat. 1020, 1898. German Pat. 108511, Oct. 18, 1898.

~Artificial Silk--l.u.s.tra-cellulose.~

C. F. CROSS and E. J. BEVAN (J. Soc. Chem. Ind., 1896, 317).

The object of this paper is mainly to correct current statements as to the artificial or 'cellulose silks' being explosive or highly inflammable (ibid., 1895, 720). A specimen of the 'Lehner' silk was found to retain only 0.19 p.ct. total nitrogen, showing that the denitration is sufficiently complete to dispose of any suggestion of high inflammability.

The product yielded traces only of furfural; on boiling with a 1 p.ct.

solution of sodium hydrate, the loss of weight was 9.14 p.ct.; but the solution had no reducing action on Fehling's solution. The product in denitration had therefore reverted completely to a cellulose (hydrate), no oxy-derivative being present.

The authors enter a protest against the term 'artificial silk' as applied to these products, and suggest 'l.u.s.tra-cellulose.'

DIE KuNSTLICHE SEIDE-IHRE HERSTELLUNG, EIGENSCHAFTEN UND VERWENDUNG.

CARL SuVERN, Berlin, 1900, J. Springer.

~ARTIFICIAL SILK--ITS PRODUCTION, PROPERTIES, AND APPLICATIONS.~

This work of some 130 pages is an important monograph on the subject of the preparation of artificial cellulose threads--so far as the technical elements of the problems involved are discussed and disclosed in the patent literature. The first section, in fact, consists almost exclusively of the several patent specifications in chronological order and ranged under the sub-sections: (a) The Spinning of Nitrocellulose (collodion); (b) The Spinning of other Solutions of Cellulose; (c) The Spinning of Solutions of the Nitrogenous Colloids.

In the second section the author deals with the physical and chemical proportions of the artificial threads.

_Chardonnet 'silk'_ is stated to have a mean diameter of 35, but with considerable variations from the mean in the individual fibres; equally wide variations in form are observed in cross-section. The general form is elliptical, but the surface is marked by deep striae, and the cross-section is therefore of irregular outline. This is due to irregular conditions of evaporation of the solvents, the thread being 'spun' into the air from cylindrical orifices of regulated dimensions.

Chardonnet states that when the collodion is spun into alcohol the resultant thread is a perfect cylinder (Compt. rend. 1889, 108, 962).

The strength of the fibre is variously stated at from 50-80 p.ct. that of 'boiled off' China tram; the true elasticity is 4-5 p.ct., the elongation under the breaking strain 15-17 p.ct. The sp.gr. is 1.49, i.e. 3-5 p.ct. in excess of boiled off silk.

_Lehner 'silk'_ exhibits the closest similarity to the Chardonnet product. In cross-section it is seen to be more regular in outline, and a round, pseudo-tubular form prevails, due to the conditions of shrinkage and collapse of the fibre in parting with the solvents, and in then dehydrating. The constants for 'breaking strain,' both in the original and moistened condition, for elasticity, &c., are closely approximate to those for the Chardonnet product.

_Pauly 'silk'._--The form of the ultimate fibres is much more regular and the contour of the cross-section is smooth. The product shows more resistance to moisture and to alkaline solutions.

_Viscose 'silk'_ is referred to in terms of a communication appearing in 'Papier-Zeitung,' 1898, 2416.

In the above section the following publications are referred to: Chardonnet, 'Compt. rend.,' 1887, 105, 900; and 1889, 108, 962; Silbermann, 'Die Seide,' 1897, v. 2, 143; Herzog, 'Farber-Zeitung,' 1894/5, 49-50; Thiele, ibid. 1897, 133; O.

Schlesinger, 'Papier-Zeitung,' 1895, 1578-81, 1610-12.

_Action of Reagents upon Natural and Artificial Silks._

1. _Pota.s.sium hydrate_ in solution of maximum concentration dissolves the silks proper, (a) China silk on slight warming, (b) Tussah silk on boiling. The cellulose 'silks' show swelling with discolouration, but the fibrous character is not destroyed even on boiling.

2. _Pota.s.sium hydrate_ 40 p.ct. China silk dissolves completely at 65-85; Tussah silk swells considerably at 75 and dissolves at 100-120. The cellulose 'silks' are attacked with discolouration; at 140 (boiling-point of the solution) there is progressive solvent action, but the action is incomplete. The Pauly product is most resistant.