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Патент USA US3053672

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Sept. 11, 1962
E. s. MACKEY ETAL
3,053,662
ANTI-STATIC PHOTOGRAPHIC FILM
Filed Sept. 25. 1958
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E.SCUDDER MACKEY
RAY E.R|CE
United States Paet
" free
3,053,562
Patented Sept. 11, 1952
1
2
3,053,662
base. We prefer to use them in combination with cer
tain Well-known anti-static agents such as the taurines
ANTI-STATIC PHOTOGRAPHIC FILM
(sulfonated amides) corresponding to the formula
E. Scudder Mackey and Ray E. Rice, Binghamton, N.Y.,
R1
assignors to General Aniline & Film Corporation, New
York, N.Y., a corporation of Delaware
Filed Sept. 25, 1953, Ser. No. 763,342
12 Claims. (CI. 96-87)
wherein R—CO denotes a radical of a fatty acid of
This invention relates to a photographic ?lm. More
vegetable origin and R1 may be either hydrogen, an ali
particularly this invention relates to a photographic ?lm 10 phatic straight chain radical, an aliphatic-aromatic radi
having a coating thereon which imparts anti-static prop
cal or an aromatic radical and X is either hyrogen, an
erties to the ?lm.
alkali metal or an organic base radical. The total number
A great amount of trouble is caused during the manu
of carbon atoms in said taurine compound is at least
facture or use of photographic ?lm on account of the
eight. The use of the taurines as anti-static agents is
accumulation of electrical charges on the ?lm. These 15 described in U.S. Patent 2,139,778. This patent particu
electrical charges are known as static and may be caused
larly describes elimination of static during the manufac
by friction of the ?lm ‘against the rolls or other portions
turing operation, but neither the compounds described in
of the machines through which it passes or merely by
the patent nor reduction of this type of static forms a
contact with dissimilar surfaces or by handling by per
part of our invention. We have found that the colloidal
sonnel who may be packing, inspecting or loading ?lm 20 silicas are particularly effective in reducing static caused
for processing. Static discharges in an unexposed ?lm
by human hand handling hereafter referred to as han
manifest themselves by the formation of irregular streaks
dling static——-for example, when ?lm is loaded by hand
or lines caused by exposure of the emulsion at such por
into processing racks, handling static occurs. The sul
tions. Attempts to overcome static in photographic
fonated amides described in the above patent are not
?lms have, for the most part, followed the lines of apply 25 effective in reducing this form of static discharge. On
ing conducting or hydroscopic materials to the surface
the other hand the colloidal silica is not effective in re
of the ?lm in order to increase its electrical conductivity.
ducing the static of manufacturing origin-for example,
The principal object of the present invention is to
during the coating or slitting operation. It is obvious to
provide a photographic ?lm with a layer containing a
those skilled in the art that the combination of anti
30 static agents would be most desirable to provide static
material capable of reducing or eliminating static.
A further object of this invention is to provide a
reduction in both the situations described above. How
photographic ?lm with a layer having incorporated there
ever, our invention is not limited by the combination as
in a material which has the ability to become molecularly
the colloidal silica is effective in reducing handling static
oriented on the surface in such ‘a way that it provides a
when incorporated in the gelatin as the sole anti-static
?lm which affords dielectric shielding particularly against 35 agent.
such static discharge which occurs during human hand '
handling.
We are unable to explain the unique action of the col
loidal silica since it does not in?uence surface resistivity
Other objects and advantages of this invention will be
(conductivity) nor does the nylon rub static generating
apparatus (a modi?cation of the instrument mentioned in
40 R. D. Fines, “Anti-Static Specialty Products Open New
description given below.
The objects of our invention are ‘accomplished by in
Markets,” paper delivered at the Chemical Specialties
corporating in layers of the ?lm or on the surface of the
Manufacturers Association meeting May 17, 1955), show
?lm a colloidal solution of hydrated silica or a polym
that the colloidal silica produces a reduction in the static
erized form of silicic acid in solution. These forms of
susceptibility of the ?lm. However, if tested by rubbing
silica are commercially known as Du Pont Ludox LS, 45 the photographic material containing the colloidal silica
Ludox SM and Ludox HS, all of which are faintly
with human hands, a very marked reduction in static dis
opalescent aqueous sols. The particles are discrete, uni
charge is recorded.
form spheres of silica which have been stabilized by in
The silicious material may be used, according to our
corporating a small amount of alkali in the product and
invention, in concentrations of 3.0% to 120% dry weight
60 based on the dry weight ofthe gelatin used in the photo
are negatively charged.
Characteristic physical properties and chemical com
graphic ?lm. We prefer to use 50% to produce the anti
position of the three products are as follows:
static effect.
I
The following example illustrates a method of apply
come apparent to those skilled in the art from the detailed
Ludox Ludox Ludox
SM
LS
HS
ing the anti-static materials to the ?lm according to our
55 invention. It is to be understood, however, that this
example is given by way of illustration only and not by
way of limitation.
Percent Colloidal Silica as SiOz _____________ ._
Surface area B.E.T. method ml/g. silica .... _.
Approximate particle diameter (mp) ________ __
Ratio, Wt, Slog/N820 _____ __
Viscosity at 25° 0., cps.
15.0
40
30.0
210
30.0
210
7
155
15
285
15
95
4. 3
13
3. 6
_
8. 5
8. 4
9.8
?lter) _____________________________________ -_
6
17
21
pH at 25° C __________________________ ._
Turbidity (Fisher Electrophotometer 525B
‘Example
60
A sensitive photographic ?lm having on one side’ the
usualqsensitive silver halide emulsion layer is surface
coated with a 2% gelatin solution containing a suitable
spreading agent and 50% dry weight of Ludox LS (based
on dry gelatin weight). Another portion of the sensitive
65 emulsion is coated with a surface layer of gelatin with
The production of these materials forms no part of our
out the Ludox LS. (It is to be understood that certain
invention.
?lm ‘such as X-ray may be ‘sensitive emulsion coated on
We contemplate applying these materials or agents to
the ?lm in various ways to decrease or eliminate static.
both sides of the base so there would be a surface coating
They may be applied (1) as a constituent of the sensitive 70 on both sides.) Sections of the coated ‘and dried ?lm
containing and not containing our antistatic agents were
emulsion or (2) as a constituent of a surface layer over
conditioned
at standard humidities (usually 20% and
the emulsion or the non-curl layer applied to the ?lm
3,058,662
3
40%) and tested for handling static. This was done by
rubbing each sheet of ?lm a speci?c number of times
with the hand (simulating processing rack loading where
by the hands are rubbed around the ?lm to assure proper
4
layer containing gelatin and an anti-static agent selected
from the group consisting of hydrated silica and polym
erized silicic acid having a particle size of 7 to 15 mg,
said agent comprising the solid contents of an aqueous sol
loading in the racks).
of said agent containing an SiO2/Na2O ratio by weight
The test sections were then processed and examined
for static discharge which can readily be noted by the
black streaks, specks, lines, or various other patterns in
of 95 to 285.
4. A photographic ?lm as recited in claim 3 wherein the
the otherwise clear section. The ?lm containing no anti
static treatment where :rubbed was completely covered
with the static discharge and would be unusable. The
sections containing the anti-static agents of our invention
tion had practically no static discharge recording and in
normal handling humidities (40-60%) were entirely free
of such defects whereas the sections which did not con
tain our novel anti-static agent had objectionable static
anti-static layer is positioned on the photographic emul
sion layer.
5. A photographic ?lm recited in claim 3 wherein the
anti-static layer is positioned between the base and the
photographic emulsion layer.
6. A photographic ?lm as recited in claim 3 wherein
the amount of anti-static agent in the anti-static layer
constitutes from 3% to 120% based on the dry weight
of the gelain.
7. A photographic ?lm as recited in claim 6 wherein the
discharge recording.
anti-static agent constitutes 50% based on the dry weight
Our invention may be used with any known photo
of the gelain.
graphic ?lm base, such as cellulose nitrate, a cellulose
8. A photographic ?lm comprising a base, a light
ester such as cellulose acetate, cellulose acetate propio 20
sensitive photographic emulsion layer and an anti-static
nate, cellulose acetate butyrate and the like.
layer, said anti-static layer containing a tauride corre
The drawing illustrates some of the various ways in
sponding to the formula
which our novel anti-static agent may be incorporated
in a photographic ?lm. In the drawing
FIG. 1 shows a cross sectional view of our novel ?lm 25
with the anti-static agent of our invention incorporated
in the light-sensitive emulsion layer;
FIG. 2 is a view similar to FIG. 1 showing the anti~
wherein R-CO denotes a radical of a fatty acid of veg
etable origin, R1 is selected from the group consisting of
static agent of our invention incorporated in a separate
hydrogen, aliphatic straight-chain radicals, aliphatic
surface layer over the emulsion, and
FIG. 3 is a view similar to FIG. 1 showing the anti
aromatic radicals and aromatic radicals and X is selected
static agent of our invention incorporated in a layer on
from the group consisting of hydrogen, an alkali metal
and an organic base radical in which tauride the total
each face of the ?lm base.
number of carbon atoms is at least eight, said anti-static
Similar reference characters represent similar elements
35 layer also containing a material selected ‘from the group
in the various views.
consisting of hydrated silica and polymerized silicic acid
Referring to FIG. -1, there is shown a base 1 having a
having a particle size of 7 to 15 mg, said agent comprising
layer of emulsion 2 thereon. The emulsion layer 2 con
tains the colloidal silicious material of our invention in
the solid contents of an aqueous $01 of said agent con~
corporated therein.
taining an siOz/NazO ratio by weight of 95 to 285.
9. A photographic ?lm comprising a base, a lightasen
sitive silver halide emulsion layer thereon and a layer
capable of minimizing curling of said ?lm, said last men
antistatic agent of our invention incorporated therein.
tioned layer containing an anti-static agent selected from
In FIG. 3 is shown the base having on each face there
the group consisting of hydrated silica and polymerized
of a layer 4 containing the anti-static material of our
45 silica acid having a particle size of 7 to 15 mp, said agent
invention, one of the layers 4 being overcoated with
comprising the solid contents of an aqueous sol of said
the ‘usual emulsion layer. One or both of the layers 4
may be of a material which minimizes curling of the ?lm.
agent containing an SiO2/Na2O ratio by weight of 95 to
285 .
The anti-static layer of our invention may be incorpo
rated in any one or all of the layers 2' or 4.
10. A photographic ?lm as recited in claim 9 wherein
the base is a cellulose ester.
Our invention is not limited to the detailed description
11. A photographic ?lm as recited in claim 9 wherein
thereof as given above, but includes all modi?cations
the anti-static agent is hydrated silica.
which fall within the scope of the appended claims.
12. A photographic ?lm as recited in claim 9 wherein
We claim:
the anti-static agent is polymerized silicic acid.
\l. A photographic ?lm having a layer thereon contain
ing gelatin and an anti-static agent selected from the
References Cited in the ?le of this patent
group consisting of hydrated silica and polymerized silicic
acid having a particle size of 7 to 15 mg, uniformly dis
UNITED STATES PATENTS
tributed in said layer, said agent comprising the solid
In FIG. 2 the base 1 is coated with an emulsion layer
2' which in turn is overcoated with a layer 3 having the
contents of an aqueous sol of said agent containing an 60
SiO-2/Na2O ratio by weight of 95 to 285.
2. A photographic ?lm as recited in claim 1 wherein
said layer constitutes a light-sensitive photographic emul
sion.
3. A photographic ?lm‘ comprising a base, a light
sensitive photographic emulsion layer and an anti-static
1,982,778
2,993,793
Andersen _____________ __ Dec. 4, 1934
Beersmann ___________ __ July 25, 1961
535,374
581,751
‘616,563
Great Britain _________ .. Apr. 8, 1941
Great Britain ________ -_ Oct. 23, 1946
Great Britain ________ __ Jan. 24, 1949
FOREIGN PATENTS
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