USRE13793E - David bachbach - Google Patents

Description

navm nacnnacn, or mmrmoanuamrnm.

IAKING COMPOUNDS WELLULOSE AND SIMILAR SUBSTANCES.

no Drawing. 10. 794,881, dated July 11, 1905, Serial 110.1893. Application fled August as, 1910. Serial No. 578,992.

Toallwhomitmay r Be it known that I, DAVID Baonnaon, a

citizen of theUnited States, residing at the city of Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Makin Compounds of Nitrocellulose or Similar ubstances Used in the Arts, Non Inflammable or Slowly Inflammable, of which the following is a specification.

I have discovered that when silicic acid can be incorporated with compounds of nitrocellulose and similar substances in the most intimate manner'and in a state of the 16 finest subdivision it will make these substances almost totally non-inflammable; but in all the methods so far devised, which simly unite silicic acid or its salts by mechanical mixture, such a result is not obtained.

'20 I have found that the most efiective way to accomplish the object is to form the silicic acid in the compound by the reaction of sulfuric acid or an acid that will free the silicic acid from its salts and from the volatile non-a ueous liquid silicates, which I have found specially well adapted for this purpose, those at present known being the silicates of methyl, ethyl, and amyl, otherwise called silicic esters. It is well un- 80 derstood that the silicates in aqueous solution, such as sodium and potassium, cannot be used in such com ounds on account of the water and of the so uble salts formed by the reactions, which would 'precipitate the py- 86 roxylin, rendering necessary the washing, dryin and redissolving of the mass, and even 516]! it is but very partially effective in taking away the great infiammability of the compound. The most complete results are 40 obtained, so far as non-inflammability is concerned, by the use of. an acid with the silicic volatile liquids mentioned to form the silicic acid by reaction and then using an antacid, like carbonate of lime, as an addition to neutralize the free acid other than silicic acid formed in the compound, as described in Patent No. 667,759, February 12th, 1901, or using an absorbent, like sulfate of lime, to retain the free acid in an inert or harmless manner, as described in Patent No. 743,422, November 9th, 1903. In either case these additions are to take place after thorough mixture of the other ingrediof lelslued Letters Patent. Reigsued Sept. 1, 1914.

for reissue cuts to form the compound. I also use dry sllicic salts, such as silicate of calcium in Iii fine powder, and an acid sulfuric preferred) to free the silicic aci and in such case I proceed very much in the same way as described in my Letters Patent No. 743,422, November 9th, 1903, and use about I the same proportion of salt and acid. In any case where a dry silicate is used the proportion of acid should be just enough to free the silicic acid and no more.

When the non-aqueous'liquid silicates I t. describe-are used with an acid, the proportion' should be about four ounces of the silicate of methyl to each pound of yroxylin, while a 10.1 r quantity of the ethy l and still larger of t e amyl sillcate is required, these latter not bein as strong in sificic acid. These liquid sihcatesare to be added tothe mixture of the pyroxylin, camphor, solvent, andacid, after these latter have been thoroughlly mixed and united. The proportions of sovent, pyroxylin, and camphor are in all processes the same, and the roportion of acid in all cases dependent on t e amount of the silicates, which can always be calculated by the methods well known in chemlstry.

It will be found best not to use the full amount of acid necessary to convert all the volatile silicates in -the compound into ure silica, as the mass allows of better han ing by having the volatile silicates in excess.

'As this is a com and of nitrocellulose which must be ma e into a mass without any precipitation of the pyroxylin, it is evident that none of the usual forms of sili- 00' date, such as silicate of sodium and potassium or any other of the salts soluble in water, can be used, nor such as by reaction with the acids used leave a soluble salt in the compound, and I disclaim themixture of acid and silicates, which produces the col= loid silicates, as they will not unite with nitrocellulose compounds properly. I use the silicate of calcium and such others as will produce insoluble salt. by reaction i Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A nan-inflammable or slow-burning compound of nitrocellulose and similar substances, produced by the addition to the usual constituents thereof the non-aqueous "silicates of ethyl, methyl and amyl and similar silicates known as silicic esters, and a free acid, substantially as described.

2. A noninfiamma le 0r slow-burning compound of nitrocellulose containing free scribed.

-DAVID BACHRACH. Witnesses:

ALLAN HERBERT FISHER, Josnrn W. SELBY.