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F72
Vol. 22, No. 6
THE FLAMMABILITY AND FLASH POINT OF CELLULOSE ACETATE FILM CONTAINING VARIOUS AMOUNTS
OF CELLULOSE NITRATE
Bv R. W. Pickard, B.Sc.,* and D. Hird, B.Sc*
THE work described in this paper was carried out at the request of a British Standards Institution Technical Committee on the " Inflammability of Safety Film." The effect which introducing different amounts of cellulose nitrate would have on the flash point and flammability of safety film was investigated. A surface coating of cellulose nitrate is at present only occasionally used, but future developments in the film manufacturing industry might call for the wider use of surface coatings and even the
inclusion of small amounts of cellulose nitrate in the body of the safety film base.
Specially prepared film containing amounts up to 16 per cent, of cellulose nitrate both in the base and as a surface coating were tested. The actual cellulose nitrate contents used are shown in Table I.
Flammability Tests
The apparatus used in the flammability test1 consisted of two steel supports in the form of a 14-in. diameter semicircle, mounted on a base with their adjacent edges 1 in. apart. A 21 -in. length of film was held in position over
Manuscript received March 24. 1953.
Table I
Flammability and Flash Point Determinations
Specimen
Thickness in. 103
Mean distance of flame spread Flash point (in.) C.
Cellulose triacetate safety base
5.3
Film did not continue to burn after the alcohol flame had burnt out
305
3% cellulose nitrate as mixture with cellulose triacetate base
5.7
Film did not continue to burn after the alcohol flame had burnt out
220
6.5% cellulose nitrate as mixture with cellulose triacetate base
5.5
Film did not continue to burn after the alcohol flame had burnt out
206
12% cellulose nitrate as mixture with cellulose triacetate base
5.0
5.0
—
16% cellulose nitrate as mixture with cellulose triacetate base
4.0
6.0
210
4% cellulose nitrate as surface coating on both sides of cellulose triacetate base
5.8
Film did not continue to burn after the alcohol flame had burnt out
186
cellulose nitrate as surface coating on both sides of cellulose triacetate base
6.5
10.0
182
14.5 °0 cellulose nitrate as surface coat 6.7 ing on both sides of cellulose triacetate base
19.5
162
Cartridge paper
7.6
19.5
288
Department of Scientific and Industrial Research and Fire Offices' Committee Joint Fire Research Organization.