Note: Descriptions are shown in the official language in which they were submitted.
Ji~,N. 912,873
~@~
METHINE 4-NITRO ENZYLIDENE DYES
This invention relates to dry silve~ shee~ materials
including as acutance agents methine p-nitro aryl~dene dyes
having an odd number o~ methine groups which are further
substituted on the aryl group attached ~o the methine chain
by a substituent having a Hammett (para) sigma parameter from
about 0.45 to about 0.63. These dry silver sheet material~
are valuable thermally developable photographic and reproduc-
tion materials.
Description of the Prior Art
Prior art teaches the use of acutance tand
antihalat~on) agents in photographic ma~er~als to enhance
the sharpness o~ images in photographic materials. They
function by absorbing light which is reflected or
refracted either at surrace interfaoes Or the photographic
materials or in the body of the photographiG materials~
Unab~sorbed reflected or refracted light de~rades the image
and thereby causes reduced resolutlon capability. Generally,
an antihalation agent is coated on either or both sides
o~ the support ~or the photographic material or between
layers of photoemuls~on. Acutance agents are gener~lly
incorporated into one or more of the photosen~itive layers.
Such acutance and antihalation agenks are discharged from
wet-processed photographi~ materials in processing baths
such as alkaline photographic developin~ baths.
One important method of reproduction o~ images is
by thermal development. This method uses no processing
liquids and there~ore precludes the use of antihalation or
acutance agents which have been produred for use in wet-
process photo~raphic materials. One such thermal develop-
ment process ~s sometimes known as the "dry silver" process,
Various aspects o~ the preparation and use o~ such materials
are described in U.S. Patents 3,152,904 and 3,457,075.
Acutance ag~nts ror use in thermally-developable
photographic materials have been described. In U~S. Patent
3,745,009 ~here are described acutance agents which are
energy-decolor$zable and suitable ~or use ln thermally-
developable photo~raphic materials but are, however, excessively
sensitive to heat during production and coating and may
decompose prematurely due to ambient heat.
In U.S. Patent 3,769,019 (3M) there are dlsclosed
acutance agents which are thermally-decolorizable protonic
d,yes although color may return spontaneously a~ter a
period o~ time.
In British Patenk 1,399,751, correspondin~ al90
~o DOS 2,242,761 and U.S. Paten$s 33984~248, 3,9~8,154 and
3,988,156, there are disclosed thermally stable, photo-
bleachable o-nitro-substituted aryliden~ dyesturfs o~ the
general ~ormula
z~
R-N~L~ ~ =CH~CH-CH ~ Y
2
wherein k - 0~ 1 or 2; m = 0 or 1; L is a methine or su~stituted
methine group; R is an alkyl, substituted alkyl, alkenyl,
aryl or substltuted aryi group; Y repr~sents the atoms
nece~sary to complete mono- or polycyclic aryl group which
may be ~urther substituted; and Z`represents the atoms
necessary to complete a mono- or polycycllc heterocyclic
nucleus which may be substituted, the heterocyclic ring
con~aining the nitrogen atom ~hown being 5 or 6 membered.
These dyestuf~s may be lncorporated ln heat d~velopable
, -2-
~3;2~
photographlc elements as part of antihalation layer. Such
elemenks may be exposed to a light pattern, thermally developed
to provide a sharp image in the element, and then the ele-
ment fully exposed to light to decolorize the antihalation
compounds. Alternatively (U.SO 39984,248, Column 12, line
27 f~., U.S. 3,988,154, Column 12, line 30 ~r., u.s. 3,988,156,
Column 12, line 41 ~f. 3 DOS, page 21, line 8 ~), the com-
pounds may be incorporaSed as desensitiz~rs in photosensi-
tive compositions for wet processing.
~t is an ob~ect and aim of this invention to
provide acutance agents ~or use in dry procossing silver
reproduction materials and particularly acutance agents
which do not tend to desensitize ~he photosensitive
compounds in said reproduction materials. A further ob~ect
o~ the ~nvenSion is to produce acutance agents which
bleach thermally under dry pr~cessing conditlonsO Other
alms and ob~ects will become apparent hereinelsewhere.
In accordance with these and other alms and
obJects of the inventlon, there are provided acutance
agents ~or use in thermally developable, photosensltive
compositions. These agents are relatively stable against
photobleaching but undergo bleaching on heating in silver
salt-con~aining thermally-developable photosensitive
compositions. Furthermore, the acutance agen~s of the
invention do not desensitize thermally~developable
photosensitive compositions in the 350 to 450 nm. range
of the spectrum. There are also provided storage-~Sable,
thermally developable, photosensitive compositions
containing su~h acutance agents.
The present invention provides a me~hine arylidene dye base
represented by t~e ~ormula
~ Z~ R2 R3
R -N~ CH=CH~ C=CH~ CH=C}~ ~ ~ T2
T
wherein: Z represents the atoms necessary to complete a mono- or polycyclic
dihydroheterocyclic nucleus having 5 to 6 atoms in the ring including ~he
N of the formula; Rl is a lower alkyl group; m = O or l; k = O, 1 or 2;
Tl is CF3 or CN; T2 is NO2; and R2 and R3 are hydrogen or together con-
stitute a condensed carbocyclic aromatic ring.
The term para as used herein refers to the Hammett (para) sigma
parameter, sometimes herein referred to as Hammett value, as defined by
Shepard, J. Am. Chem. Soc., Vol. ~5, pg. 1314 et seq. ~1963).
It will be seen that the acutance agents invention are similar
formally in many respects to those described in British 1,399,751 and DOS
2`:~242,761 and are obtained by replacing o-nitro-substituent by electron
withdrawing groups having lower Hammett para sigma, i.e.,
r ~J, ~ 4 -
(~para) values; of from about 0.45 to about 0.63.
The Hammett para sigma parameter of the nitro
group is much higher, 0.778, and it is considered surpri~ing
that a much better balance of thermal and photosensitive
properties can be obtained together with substantially
complete loss of desensitizin~ properties by such a
relati~ely simple ~ormal change in structure. The
presence o~ nitro groups in the 4-position is, however,
not detrimental to the desired properties.
It is ~ound that suitable T~ groups are aprot1c
electron withdrawing groups having a apara value of 0.45 to
0.63, CF3 (~para ~ 0 55) and CN (~para ' 0.63). Such values
are readily ascer~ained by reference to report~d tables, ~or
example, in Shepard, supra.
Groups having a ~para value less than about 0O45
become increasingly resistant to thermal decolorization and
groups have a ~para value above about 0~63 become increasingly
more light unstable.
The acutance agents of Formula I are of the
class o~ odd-numbered arylidene dye bases. The preparation
of the acutance agents is by methods similar to the
generally known methods for preparakion o~ odd-number~d
methine cyanine dye bases such as are described in, among
other re~erences, Chapter XI,
Compounds by Hamer~ Interscience Publishers (1964).
The monomethine dye baæes, i.e. dye bases where
k of Formula I above is zero, can be prepared by condenæation
in the presence of an ac~d acceptor, e.g., tertiary amine,
Or a halogenated aromatic compound of the rormula:
2.1L~
R2~R3
Y~ T~ II
T ~
wherein R29 R3, Tl and TZ are de~ined a~ above, and Y is
~luorine, chlorine or bromine with a heterocyclic quaternary
ammonium compound of the ~ormula:
z ~
R~ CH-CH ~-CH3 ~ III
wherein Rl, Z and m are de~ined above, and X is an anion
such as; for example, a halogen ion, a p-toluenesul~onate
ion, a rluorosul~o~ate ion or the like. &enerally, the
condensation is carried out in an aprotic solvent such as,
for example, acetonitrile, benzene or dlmethyl~ormamide.
Reaction conditions may be ~rom about 50-150~C ~or 1 to 3
hours, or as little as a few minutes when unwanted side
reactions may occur. The produ¢t may be isolated by well
known procedures such as crystalllzation or removal of
sol~entO
The monomethine dye bases can be prepared by
reac~ion in the presence of an acid acoeptor o~ quaternized
heterocyclic compounds having a phenyl- or alkyl-thio
substituent in place of the methyl, i.e., Or the
structure:
__ z ~
R~ CH-CH~=mC-SRs IV
here Rs is phenyl or alkyl of 1-4 carbon atoms~ with
aromat~c compounds of the ~ormula:
R2 R~
H3C ~ T~ V
wherein R~; R~, T~ and T are de~ined as above.
The trlmethine dye bases, i.e. those dye bases
where k-l in Formula I above, can be prepared by reaction
of a heterocyclic guaternary ammonium compound, e.g.j of
Formula III above, with diphenyl~ormamidine or an equimolar
mixture o~ diphenylformamldine and triethylorthoformate to
give the corresponding ~-anilinovinyl derivative:
z ~
R'-N~CH-CH ~mC-CH=CH-NH ~ ~ VI
where Rl, Z, L, X and m are de~ined above. The ~-anilinovinyl
derivatives are then caused to condense with an aromatic
compound such as the aromatlc compounds of Formula V to
give the trimethine dye bases. Reaction conditions are
similar to those ued for the preparation of the monometh$ne
dye bases.
The pentamethine dye bases can be prepared in a
manner similar to that used ~or the preparation of the
trimethine dye bases using ~-an~linoacrolein anil
hydrocloride in place o~ diphenylformamldine to give
the corresponding ~-anilinobutadienyl derivative
z ~
R~ CM-CH~C-CH~CH-CH-CH-NH-CcH5 ~ VII
., ~ .
wherein Rl~ Z, X and m are as de~ined above. The compo~nd
of Formula VII is then condensed, under the conditions
used for reaction o~ Compound III, with an aromatic compound
o~ Formula V ko yield the pentamethine dye base.
Examples of acutance agents o~ Formula I
include the follow~ng compounds.
--7--
~Z~14
Compound
1. 4-(2-cyano-4-nitrobenzylidene)-1-methyl-1~4-di-
hydropyridine
2. 4-(2-tr~fluoromethyl 4-nitrobenzylidene)-1-methyl-
1,4-dlhydropyridine
3. 4-(2-cyano-4-nitrobenzylidene)-1-methyl-1,4-di-
hydroquinoline
4- 4-t2-tri~luoromethyl-4-nitrobenæylidene)-l~methyl-
1,4-dihydroquinoline
5. 2-(2-cyano-4--nitrobenzylidene)-1-methyl-19 2-di-
hydroquinoline
6. 2-t2-cyano-4-nitrobenzylldene)-1-ethyl-1,2-di-
hydroquinoline
7. 2-t2-cyano-4-nitrobenzylidene)-1-methyl-6-ethoxy-1,4-
dihydroquinoline
8. 2-(2-cyano~4-n~troben~ylidene)~l ethylbenzoth~azoline
9. 4-t2-cYano-4-nitrobenzylidene)-l-t2--nitrobenzy~ 4
dihydropyridine
10. 2-t2,4-dicyanobenzylidene)-1-ethylbenzoxazoline
11. 2-(2-cyano-4-nitrobenzylidene) l-ethylbenzoxazoline
12. 2-~3-(2-cyano-4-nitrophenyl)allylidene]-1-methyl-
1~2-dihydropyridine
130 2-C3-(2 cyano-4-nitrophenyl)allylidene]-1-methyl-
1,2-dihydroquinoline
14. 2-~3-t2-cyano-4-nitrophenyl)allylidene] 1-ethyl-1,2-
- dihydroquinoline
15. 4-~3-(2-cyano-4-nitrophenyl)allylideneJ-l-methyl~
1,2-dihydroquinoline
16. 2-~3-(2-cyano-4-nitrophenyl)allylidene~-1-ethyl-
benzothiazoline
--8--
Com~
17~ 2- r 3-(2,4-di¢yanonaphthyl-l)allylidene]-1,3-dimethyl-
5-ethoxybenzimidazoline
18. 2-[5-t2-cyano-4-nitrophenyl)pentadiene-2,4-ylidene]-
1-methyl-1,2-dihydropyridine
19. 2-C5-(2-cyano-4-nl'crophenyl)pentadien-2,4-ylidene~-
l-ethyl-5-methylbenzoth$azoline
20. 2-C5-(2-cyano-4-nitrophenyl)pentadien-2,4-ylidene]
l-methyl-1~2-dihydroquinol~ne
1021. 4-~2-cyano- 4-nitro~ en zylidene)l-phenyl-1,4-dlhydro-
pyridine
22. 2-(2-cyano-4-nitrobenzylidene)-1-phenylbenzoxazoline
23. 4-(2-cyano-4-nitrobenzylidene)-1-(4-methoxyphenyl)-
1,4-dihydropyridine
1524. 4-~3~ cyano-4-nitrophenyl)allylidene]-1-(2-
ethoxyethyl)-1,4-dihydropyridine
~5. 4~~3-(2-cyano-4-nitrophenyl)allylidene~-1-allyl-1,4-
dihydropyrldine
26. 2-(2-cyano 4-nitrobenzylidene)-1-ethyl-6-methoxy-
1,2-dihydroqulnoline
The acutance agents o~ Formula I are use~ul in
thermally-developable photosensitive co~posikions such as
those described in U.S. Patents 3,457,075, 3,589,901 and
3,589,0g3. They are optimally used in concentrations of about
0.01 to about 0.1 par~s by weigh~ (30 to 300 m~cromoles)
of acutance agent having a molecular weight of about 300 per
100 parts by weight o~ photosensitive dispersion. The use o~
more acutance agents in coating an emulslon produces an
increase in fog le~el and increase in residual stain.
Lesser amounts are generally ~ound to be ine~fective.
Com~ound
17. 2-[3~(2,4-dicyanonaphthyl-l)allylidene]-1,3-dimethyl-
5-ethoxybenzimidazoline
18. 2-C5-(2-cyano-4-nitrophenyl)pentadiene-2,4-ylidene]-
1-methyl-1,2-dihydropyridine
19. 2-[5-(2-cyano-4-nitrophenyl)pentadien-2,4-ylldene~-
l-ethyl-5-methyPben~oth~azol$ne
20. 2-C5-(2-cyano-4-nitrophenyl)pen~adien-2~4-ylidene~-
l-methyl-1~2-dihydroquinoline
10 21. 4-(2-cyano-4-nitrobenzylidene) 1-phenyl-1,4-dihydro-
pyridine
22. 2-(2-cyano-4-nitrobenzylidene)~l-phenylbenzoxazoline
23. 4-(2-cyano-4-nitrobenzylidene)-1-(4-methoxyphenyl)-
1,4-dlhydropyridine
15 24. 4-c3-(2-cYano~4wnitrophenyl~a:Llylidene]-l-(2
ethoxyethyl)-1,4-dihydropyridine
25. 4-r3-(2 cyano-4-nitrophenyl)allylidene]-1-allyl-1,4-
dihydropyridine
26. 2-(2-cyano-4-nitrobenzylidene)-l~ethyl-6-methoxy-
1,2-dihydroquinol1ne
The acutance agents o~ Formula I are useful in
thermally-developable photosensitive compositions such as
those described in U.S. Patents 3,457,075, 3,589,901 and
. 3,589,093. They are optimally used in concentrations of about
0.01 to about 0.1 parts by weight (30 to 300 micromoles)
o~ acutance agent having a molecular weight o~ about 300 per
100 parts by weight o~ photosensitive dispersion, The use o~
more acutance agents in coating an emulslon produces an
increase in fog level and increase in residual stain.
Lesser amounts are generally ~ound to b~ ineffective.
_g_
Prer~rably about OfO2 to 0.05 parts and more (50 to 150
micromoles) pre~erably about 0.02 to Q.035 parts (50 to 120
micromoles) o~ acutance agent having a molecular weight of about
300 is used per 100 parts o~ photosensitive dispersion.
Amounts expressed as micromoles are applicable to acutance
agents o~ ~he invention in general.
The invention is now further explained ~y examples
showing the preparation and use o~ acutance agents of
Formula I. It will be recognized that with complex molecules
melting points may be a~fected by rate of heating, atmosphere
and also crystalline ~orms as well as tendency o~ the
compounds to decompose.
EXAMPLE 1
Preparation o~ 4-~2-cyano-4-nitrobenzylidene)-l~methyl-1,4-
di~ydroquinoline.
Lepidine methyl fluorosulronat;e ~51.4 g., 0.2 moles
and 2-chloro-5-nitrobenzonitrile (36.5 g., 0.2 moles) were
d~ssolved in 350 ml. o~ dry acetonitrll~. The solution was
hea~ed to reflux and, whlle stirring v~orously, trlethyl-
amine (40.4 g., 0.4 moles) was added during about ~our minukes.
An intense deep purple color developed immediately. ~he
mixture was held at rerlux for about on~ hour and cooled in
an ice water bath. The green iridescent crystalline product
was oollected, washed successively with a small amount o~
acetonitrile, water, and diethyl ether, and drled at 60C.
There was obtained 35.8 g. (59% of theory) Or product hav~ng
a melting po~nt Or 220-222C, recrystallized from acetonitrile
for analysis:
Calcd. for C~uHl3N~o2: %C, 71.3; %H, 4.32; ~N, 13.8
Found: %C9 71.3; gH, ~.3; %N, 14.2
--10--
l~Z~
EXAMPLE 3
1,4-dih~dropyridine.
The procedure of Example 1 was repeated using an
equlvalen~, i.e. equimolar, amount o~ 1 (2-nitrobenzyl)-4-
methylpyridinium chloride in place o~ lepidlne methyl
~luorosulfonate. A deep blue dye base h~ving m.p. 193-201C.
was obtalned in 47% o~ theory.
Calcd. ror C20H~N404: %C, 64.2; %H, 3.77; %N1 15.0
Found: %C, 63.6; %H, 3.~0; %N, 15.3
IR spectra were consistent with the structur~ of Compound 9.
NMR peaks (~ units in parts per million are found at 8.30,
.20, 7.6-8.1, 7.49, 6.90, 5.70, and 5.47.
EXAMPLE 4
Preparation of ll-(2-trir~ ~ trobenzylidene)-l-
methyl-l ? 4-dihydroquinoline.
The procedure o~ Example 1 was repeated using
an equivalent amount o~ 2-chloro-5-nitrobenzotri~luorlde in
place of 2-chloro-5-nitrobenzonitrile. The product obtained
had a melt~ng point of 173-5C. On recrystallization ~rom
carbon tetrachloride and then methanol, a deep purple
crystalline produc~ was obtalned.
Calcd. for CldHl-dF~N20a: %C, 62.4; %H, 3.78; gN, 8.08; %F, 16.46
Found: %C, 62.4; %H, 3.7; %N, 8.8; %F, 16.3
IR spectra were consistent with the structure o~ Compound 4.
NMR peaks (expressed in ~ units in parts per million are found
at 8.33, 8.29, 8.02~ 7.90~ 7.1-7.7, 6.66, 6.39 and 3,60.
12-
~ ~z ~3~
Preparation o~ ?-E3-(2-cYa o-4-nitrophenyl)allylid-ene~
ethyl-l z-~b~e5YYn99Ine.
The condensa~ion of 4.02 g. (0.01 mole) of 2_(2-
anilinovinyl)-l-ethylquinollnium iodide (prepared as described
in British Patent 344,40~ m.p. 263-5C (dec.)) with 2-cyano-
4-nitrotoluene (1.67 g., 0.01 mole) was e~fected in 15 ml.
o~ dimethylformamide containing 2 ml. of acetlc anhydrlde
by heating the react~n mixture to re~lux, addin~ 1.01 g.
(O.01 mole) Or triethylamlne, heatin~ at re~lux ~or 1 to 2
minutes and cooling rapidly, The precipitate was collected,
washed successlvely with dimethyl~ormamide 9 water and
ether and ~hen dried to y~eld 47% of theory o~ blue dye base
m.p. 250-252C.
Calcd. ~or C~IHl7N302: %C, 73.4, %H, 4.98; %N, 12.23
~ound: %C, 72.4; %H, 4.9; %N, 12.2
IR spectrum was consistent with the structure o~ Compound
14 but also ~ndicated the sample to be contaminated with
dimethylformamide.
When 2-(2-anilinovinyl)-1-ethylquinolinium iodide
used above is replaced by 4-(4-anilinobutadien-1,3-yl)-1-
methyl~uinolinium iodide there is obtained 4-C5-(2-cYano-4-
nitrophenyl)pen~adien-2,4-ylidene]-1-methyl-1,4-dihydropyridine.
This arylidene dye base is chloro~orm is bright gre~nish.
blue having an absorption maximum o~ 645 to 660 nm.
The procedure of this example was repeated
usin~ equivalent quantities o~ the necessary quaternary
compounds and 2-cyano-4-nltrotoluene to give the following
compounds.
134
Table 1
Structure
o~ Dye
Com~ounds . Meltin~ Point C
13 240-~ (dec.)
14 250-2
235-40 (dec.)
16 221-2 dec. (235)
EXAM
A thermally de-velopable photosen~itlve composition
was prepared by blending in a m~xing apparatus 5 ~. o~ poly-
vinyl butyral and 500 æ. o~ a dispersion o~ 13.8 ~arts
by weight silver behenate in 86.2 part~ by weight o~ a mixture
in parts b~ volume Or 68 parts methylethyl ketone, 25 parts
toluene, and 7 parts methylisobutyl ke~one. After the mixture
had beoome homogeneous, it was placed under "safe" light
condi~ions as known to those of skill in the art and 20 ml.
o~ a solution o~ lM hydrobromlc acid ln methanol (48g HBr
diluted with methanol) was added dropwise to the vl~orously
20 stirring mixture. After stirring ~or 20 minutes at 25C,
2.5 ml. o~ 0.15M mercuric bromide in methanol was added
followed by 25 g. polyvinyl butyral and stirring was continued
for 10 minutes, avoiding heat build-up as the v~scosity
o~ the mixture increased. There then was added 10 mg. o~
25 the optlcal sensitizer ~dispersed ln 10 ml. of methanol)~
3-ethyl-5[(1-ethyl-i,2-dihydroquinolinylidene-2~ethylidene]-
2-~3-carboxymekhyl-4-oxo-2-thio-5 thiazolidinylidene)-4-
~hiazolidone available from Example 2 oP U.S. Patent 3,719,495.
Okher sensitizers can be used a~ desired. The mixture was
3 stirred 20 minutes and 100 g. was withdrawn ~or preparation
-14-
2~1~3~
of a control thermally-developable material (designated A).
To the remainder was added 150 mg. o~ the acutance dye base
of Example 1 and the composition (designated B) containing
acutance a~ent was stirred for another 30 minutes.
Bo~h compositions, A and B, were knife coated at
125 microns onto polyester film and dried 5 minutes at 90C
in a forced dra~t oven. Both dried films were ~hen topcoated
at 75 microns with a dèveloper layer composition of 81 parts
methylethyl ketone, 5 parts methanol, 1.5 parts phthalazinone,
7.5 parts o~ bis(2,2'-dihydroxy-3,3',5~5'-ketramethyldiphenyl)-
(2,4,4-trimethylpentyl)methane (available as NONOX WSO from
I.C.~., Lkd.) and 5 parts of vinyl chloride/v~nyl acetate
copolymer (available as VYNS rrom Union Carbide~. Films
of this type are of relatively high contrast values. The
topcoated ~ilms were dr~ed five mlnutes at 90C.
Portions of each of the ~ilms 9 Film A (the control
not containing acutance agent) and Film B (containing acutance
agent), were contact exposed through a mask overlaid with a
0~4 continuous density wedge to tungstlen illumination
modulated by a 560 nm. narrow band ~llter. The mask had a
rectangular aper~ure with a width of about 5.5 mm. and a
length of 120 mm. The coated films were then dev~oped by
heating for 16 seconds at 125C and the width of the image
that formed measured in millimeters (believed to be - 0.01
mm) at optlcal densities of 2 and 3 tabulated in Table 2. The
comparative values obtain~d are indicative of the effective-
ness of acutance agents.
Table 2
O~tical Densit~ - 2.0
Width of Width o~ Peraent
M~ . Image Flare
Film A 5.544 mm. 5.557 mm. 0.23
Film B 5.546 mm. 5~546 mm. 0.O
O~ cal Densit~ ~ 3.0 _
Width of Width o~ Percent
Mask_Aperture ~3~ Flare
Film A 50660 mm. 6.737 mm. 19.0
Film B 5.664 mm. 5.664 mm. 0.O
From the above daka, it is apparent that incorporat~on
of t~e acutance agent o~ the inventlon eliminated lmage ~lare
whlch without the agent would amoun~ to 0.23% o~ the image
width at a densi~y Or 2~0 and 1~% at an lmage density o~ 3Ø
EXAMPLE 7
A series Or low contrast filrns are pr2pared both
wlth and without an extensive æeries o~ the acutance dyes
enumerated above. This procedure plac~d the developer and
toner ln the lma~e layer rather than in a separate layer as in
Example 6.
A suitable vessel is charged with 750 g of a
dispersion as in Exam~le 6 of sllver behenate, 45 g methyl
ethyl ketone and 0.75 g polyvinylbutyral and the su~penslon
mixed at about 22 for 15 minutes at which time a mlxture
of 36 ml o~ 1.0 M HBr in methanol and 9.5 ml of 0.1 M HI
in methanol is added and stirr~ng is continued ~or 1 hour.
To the mixture is added 5.18 ml Or 0.5 M Hg Br2 in methanol
~ollowed by a further 85 g Or polyvinylbutyral and stirring
is con~inued ~or 20 minutes. A dispersion of 0.022 ~ o~ the
same sensitizer used in Example 6 in 20 ml o~ methyl
-16-
a3~
ethylketone is added to the total mixture which is then stlrred
ror 75 minutes before adding 24 g of the "NONOX WS0" used
in Example 6 and 7.5 g o~ phthalazinone and stirring is
continued for 10 minutes to provide the basic emulsion.
Several such batches are used in subsequent tests. Controls
are prepared containing 3 ml. chloroform but no acutance dye
and coated at a wet level o~ 125~ on 75~ polyester ~ilm and
after drying 3 0 5 minutes at 90C overcoated with a non-
functlonal protective wet coat of 75~ vinyl acetate/vinyl
chloride (39%) in 80:20 methyl ethyl ketone: methanol dried
in the same wa~. The controls exposed are at s~veral
dirrerent wavelengths o~ light through a mask as described
in Example 6 developed 15 seconds at 127C and measured at
density o~ 3.0 for mask aperture and image width in
millimeters (believed accurate to about 0.01 mm~ as shown
in Table 3.
Table 3
Width o~ Width o~ Percent
(nm) Mask Aperture ~E~ __ Flare
510 5 D 538 7.027 27
560 5.559 7 9 26
620 5.550 6.766 2~
6~0 5.562 7.021 26
Samples for testing acutance dyes are prepared by
dispersin~ 40 micromoles of the dye to be tested in 3 ml
chloroform in a vessel and adding 50 g aliquots of the
emulsion prepared above. The vessels are shaken well three
times at intervals Or 10 minutes and coated as described
above for the controls. Exposure is er~ected at varlous
wavelengths as controlled by ~ilters usin~ masks as above.
Table 4 shows the acutance dyes by re~erence to the figures
-17-
~ 3 ~
toge~her with molecular weight, weight o~ dyestu~f (mgm per
aliquot), wavelength, mask width (mm), image width at D - 3.0
and percent flare.
Tabl~ 4
Acutance Weight Width Width
Dye Mole¢ular o~ A o~ Mask o~ P~rcent
F~æure Wei~ht~ Q nm~ Aperture Image Flare
1 253 10.2 560 5.549 6.609 19
2 346 13.9 540 5.567 6.128 10
3 303 12.2 560 5.542 6.214 12
303 12.2 540 5.569 6.043 ~.5
6 317 12.7 540 ~.569 6.190 11
7 347 13.9 560 5.558 5.989 7.8
9 347 15.0 540 5.567 6.563 18
12 ~77 11.1 640 5.570 6.749 21
14 343 13.8 640 l~.550 6.028 8~6
14 343 13.8 620 '~5~ 5.935 7.0
329 13.2 640 5.570 6.~88 9.3
16 349 1~ 620 5.548 6.208 12
~3
