Note: Descriptions are shown in the official language in which they were submitted.
1~54839
The present invention is directed to a recording method
for forming a permanent or stabilized image resulting from the
information-wise exposure of a free radical photo-sensitive
aterial as hereinafter defined, wherein said method includes
the inactivation of the photosensitivity of the compound pro-
ducing the free radical.
By the term "free radical photosensitive material"
employed in the present description is meant a photosensitive
material in which at least one of the photosensitive ingredients
is an ultraviolet and/or visible light sensitive organic poly-
halogen compound producing photoradicals on exposure with said
radiation.
Photographic dye-forming systems based on the use of said
polyhalogen compound and a dye precursor compound have been des-
cribed, e.g. by R.A. Fotland in J. Phot. Sci., 18 (1970), 33-37,
in the United States Patents 3,102,810 and 3,377,167, the United
Kingdom Patents 1,151578 and 1,073,345 and in the Belgian Patents
771,848 - 786,973 - 787,339 and 790,340 corresponding with the
published German applicatlons Nos. 2,142,966; 2,241,563;
2,244,783; and 2,251,105, respectively.
In all these dye-forming systems carbon tetrabromide and/
or iodoform are the most commonly used photoradical-generating
compounds because these compounds excel in photosensitivity when
compared with other representatives of the class of photosensitive
organic polyhalogen compounds.
One of the presently known stabilization techniques makes
use of the volatility of the carbon tetrabromide, which can be
~OSW39
removed from the non-exposed portions of the recording mate-
rial relatively easily by evaporation. A suitable stabiliza-
tion temperature is, e.g., in the range of 100 to 150C.
~ he evaporation of carbon tetrabromide in the environment
of the operating personel poses, however, a problem since the
compound is physiologically not inert and classified as being
toxic (see I. ~ax, Dangerous Properties of Industrial Mate-
rials (1968)).
~ he toxicity problem still remains when applying another
commonly used stabilization technique that is based on the
extraction of the photosensitive polyhalogen compound.
In the known extraction-stabilization technique a solvent
for the photosensitive polyhalogen compound is used, which
solvent does not affect or only weakly affects the binding agent
of the recording layer. Some solvents such as diethyl ether,
although being excellent extraction agents cannot be used for
the risk of explosion. Other suitable extraction solvents
belonging to the class of liquid halogenated aliphatic hydro-
carbons are not miscible with water and must not be drained
off in the sewer.
Now a recording process has been found including image
stabilization comprising the steps of :
(1) image-wise exposing to active electromagnetic radio-
tion a recording material containing in a recording layer
a dye precursor compound and at least one photosensitive organic
polyha~ogen compound capable of producing photoradicals and
GV.781 PCT - 2 -
lOS4839
a dyestuff with said dye precursor compound when exposed with
ultraviolet radiation and/or visible light, and
(2) by heating transforming the non-decomposed poly-
halogen compound into a non-photosensitive substance by reac-
tion with at least one stabilising substance selected from
the group consisting of triphenylamine,
a "soft-base" containing an element of the group consisting
of phosphorus, arsenic, antimony, bismuth, selenium and
tellurium,
and an ~,~ -ethylenically unsaturated compound in which at
least the ~-carbon atom of at least one ethylene group is
linked to cyano, a cyanomethyl group, an aGyl group, an acyl-
oxy group, an alkoxycarbonyl group, a carbamoyl group or an
aryl group, said stabilizing substance(s) being available
in a layer adjacent to the recording layer for allowing the
reaction with non-photo-decomposed polyhalogen compound on
heating.
By the wording "soft base" is understood in the present
invention a substance whose logarithm of the reaction rate
constant of the reaction of the base with the trans-Pt
(C5H5N)2Cl2 complex is larger than 3. Soft bases having that
property are described in Science 151, 172-7 (1966) and in
J.Chem.~duc. 45, 581-587 (1968) more particularly in Table
of the article "Acids and Bases, HSAB" by Ralph G.Pearson.
The present invention includes further an integral copy
material containing the photosensitive polyhalogen compound
and stabilizing agent out of direct chemical contact from each
GV.781 PCl - ~ -
lOS4839
other at room temperature (20-30C) but in such a condition
that reactive contact is effected through heating of the mate-
rial at a temperature above 60C.
In the integral copy material system different techniques
of keeping the polyhalogen compound and the "soft base" and/or
sterically hindered phenol out of reactive chemical contact
below 60C may be applied. For example, the reactants are
kept out of direct chemical contact by enveloping at least
one of the reactants in a capsule or droplet that contains
a shell or envelope of a material, normally a polymeric mate-
rial or wax that prevents the direct contact with the other
reactant. ~he capsule shell or droplet envelope is ruptured
or softened by heating, as a result of which the reactants
enter into reactive contact.
Preferred integral copy materials applied in the present
invention contain the photosensitive organic polyhalogen com-
pound and stabilizing substance out of chemical reactive con-
tact at least below 60C in apart binder layers in which the
layer containing the stabilizing substance is a layer adjacent
to the layer containing the polyhalogen compound and is
applied from a solution in a volatile liquid, which is a
non-solvent for the polyhalogen compound and the binder con-
tained in the imaging layer comprising the polyhalogen com-
pound and dye precursor compound. Premature reaction is
avoided effectively when in a first layer on the support,
e.g. resin support, of the recording material a vinyl car-
bazole homopolymer or copolymer binder containing the dye
GV.781 PCT _ 4 _
1054~39
precursor compound, e.g. a spiropyran compound and polyhalogen
compound and being insoluble or poorly soluble in ethanol
or methanol, is coated and the stabilizing substance is
app:Lied in a polymeric binder that is highly soluble in
ethanol. Preferred binders for the covering layer are cel-
lulose nitrate, polyvinyl acetate, ethylcellulose and poly-
vinylbutyral.
If coated on a removable carrier, the very vinyicarbazole
polymer or copolymer film containing the dye precursor com-
pound and polyhalogen compound may serve as the support butpreferably it is permanently supported on a separate heat-
resistant film, e.g. a polyester resin film, preferably a
polyethylene terephthalate film. ~he ratio of vinyl carba-
zole, homopolymer or copolymer to dye precursor compound in
the integral sheet system material may be in the range of
about 20 to 2 parts by weight of polymer to 1 part by weight
of dye precursor compound.
~ he triphenylamine and "soft base" stabilizing agent
are preferably present in the recording material at least
in equimolar amount with respect to the photosensitive poly-
halogen compound.
~ he molar amount of ,~ -ethylenically unsaturated
compound is preferably at least 2 times as large as the
molar amount of the photosensitive polyhalogen compound in
the recording material.
If plasticizers are used in the layer containing the
triphenylamine, "soft base" and/or ~,~ -ethylenicalIy unsatu-
GV.781 PC~ - 5 -
:
1 1~54839
rated compound preference is given to those that do not opa-
cify the recording material, in other words those that are
compatible with the binder, e.g. cellulose nitrate. The
plasticizer should therefore be soluble in the same solvent
as the binder. It should be essentially non-volatile in
normal storage conditions. Suitable plasticizers for cellu-
lo~e nitrate are polyalkylene glycol and camphor.
Particularly useful stabilizing agents of the "soft base"
type of the elements phosphorus, arsenic, antimony or bismuth
correspond to the following structural formula :
r
- Ar
~ Ar
wh~rein :
X is phosphorus, arsenic, antimony or bismuth, and
Ar is an aryl group e.g. a phenyl group.
~he use of such triaryl compounds in a photosensitive
mixture containing a leuco dye compound and a photosensitive
organic halogen compound has been described already in the
United Kingdom Patent Specification 1,161,058.
Preferred stabilizing agents of the "soft base" type are
given in the following ~able 1 with their structural formula,
melting point and reference to their preparation.
GV.781 PCT - 6 -
1054~39
q!able 1
,
. . _ _ .
No.Structural formula point or Preparation
Boiling ref.
,~ point (C)
ll
1 ( ~ )3 74-76 P.Pfeiffer, Ber.
37, 4620 (190~)
2 (HO-~ )3P.H20 200 O.Neunhoeffer!, Ber.,
94, 2515 (1961~
3 (cH3-cH2-cH2-cH2)3p b.p. W. Davies, J.Chem.
(50 mm Soc., 1929, 33
l Hg)
4 ( ~ )3Sb 50 G.Hiers, Org.Synth.
Coll.Vol.1, 535
(CH3- ~3 )3Sb 127 !I~.~alalaevce,
J.Gen.Chem.
(i946;
6 ( ~ )2Se b.p. H. Leicester,-
165 Org.Synth.Coll.
Hg) Vol. II, 238
!
a "~-Ethylenically unsaturated compounds for use as sta-
bilizing agents according to the present invel~tion correspond
to the following general formula:
X- (CH=CH-)nY
wherein:
X represents an aryl group e.g. phenyl, CN, -CH2CN,,an acyl
group e.g. banzoyl, an acyloxy group, an alkoxycarbonyl
GVo 781 PCT - 7
' iO54839
group, an aryloxycarbonyl group or a carbamoyl group,
Y represents hydrogen or one of the groups mentioned under
X, and
n is 1 or 2.
Preferred unsaturated compounds are given in the following
q~able 2 with their structural formula, melting point and
reference to their preparation.
q!able 2
.,.. ____ .
No. Structural formula Boiling Preparation ref.
point (bp
or melt-
_ (ng)p(ooc)t
1 CH2=CH-CN (bp) i8 C.Monreu, Bull.Soc.
Chim.France (4)
27, 903
2 CX3-11-0-CX=CH2 (bp) 72 1 ( 954)R., 24, 459
3 CH2=CH-CX2CN (bp) 118 P.Bruylants, BulI.
Soc.Chim.Belge, 31,
4 ~3-CH=CH-~3 (mp) 125 Beilsteirl, E II
Vol. 5 (1943), 537
~ -CH=CH-CH=CH- G~> (mp) 147 Beilstein, E II
Vol.5 (1943), 589
6 ~3-CH=CH-C~ (mp) 59 Beilstein, E II
_ Vol.7 (1948), 423
~ he above mentioned stabilizing agents that are parti-
cularly advantageously used in conjunction with carbon tetra-
bromide are also effective in the stabilization of photo-
GV.781 PC~ - 8
lOS4~39
sensitive materials containing photosensitive organic poly-
halogen compounds other than carbon tetrabromide.
Photosensitive organic polyhalogen compounds that ob-
tain reduced photosensitivity by reaction with the mentioned
stabilizing agents are within the scope of the following
géneral formula that includes carbon tetrabromide : -
C
B/ \Y
wherein :
each of A, B, X and Y is a halogen atom of the group of
chlorine, bromine or iodine, or
wherein one of said radicals A, B, X or Y represents an
alkyl group, including a substituted alkyl group, e.g.
a halogen-substituted alkyl radical, a hydroxy-alkyl
radical or an aralkyl radical, e.g. benzyl, a quinoxaline
group, an aryl group, a substituted aryl group, an aroyl
group or an aryl sulphonyl group and the other radicals
chlorine, bromine or iodine, or wherein two of said
radicals A, B, 2 or Y represent an aromatic acyl group,
e.g. benzoyl, and the other radicals chlorine, bromine
or iodine.
Particularly suitable representatives falling within
the scope of that general formula are organic halides such
as carbon tetrabromide, bromoform, iodoform, hexachloro-
ethane, hexabromoethane, pentabromoethane, 1,1,2,2-tetra-
bromoethane, ~,q,~-tribromoacetophenone,~ ,a,-tribromo-
GV.781 PCT - 9 -
1054839
methylsulphonylbenzene, and its chlorine- or nitro-substi-
tuted derivatives, tribromoethanol and the 2-tribromomethyl-
guinoxaline compounds described in ~elgian Patent 757,145.
The following examples illustrate the present inven-
tion without, however, limiting it thereto. ~he parts, per-
centages and ratios are by weight, unless otherwise indicated.
~xam~eae_1
24 parts of carbon tetrabromide, 24 parts of iodoform,
24 parts of 3-methyl-di- ~-naphtospiropyran, 100 parts of
poly-N-vinylcarbazole, 2 parts of silicone oil dissolved in
1446 parts of trichloroethylene and 1336 parts of methylene
chloride were used for the coating of the imaging layer A on
a polyethylene terephthalate support of a coverage of 95 ml
per sq.m.
~he stabilizing layer B was coated on top of layer A
in a ratio of 38 ml per sq.m with the following composition :
50 ml of a 5 % solution of cellulose nitrate in ethanol and
50 ml of a 10 % solution of triphenylstibine in ethylene
glycol monomethyl ether.
After drying, this material was exposed for 20 s to
ultraviolet radiation in an Actina SH (trade name) diazo
copier containing an U.V. lamp of 1000 W and heated for 8 s
at 130C. A light-stable image was obtained.
Example 2
On the same imaging layer as described in Example 1
a stabilizing layer was coated in a ratio of 76 ml per sq.m
GV.781 PC~ - 10 -
1054839
with the following composition : 50 ml of a 10 % ethylcellu-
lose solution in dioxan and 50 ml of a 10 % triphenylstibine
solution in ethylene glycol monomethyl ether.
After drying, this material was exposed to U.V. radiation,
as described in Example 1, heated for ~0 s at 130C (or
for 90 s at ~20C). A light-stable image was obtained.
Example 3
On the same imaging layer as described in Example 1 a
stabilizing layer was coated in a ratio of 76 ml per sq.m
with the following composition : 50 ml of a 10 % polyvinyl
butyral solution in ethanol and 50 ml of a 7 % triphenylstibine
solution in ethylene glycol monomethyl ether.
After drying, this material was image-wise exposed as
described in Example 1, and heated for 6 s at 1~0a.
light-stable image was obtained.
ExamPle 4
On the same imaging layer as described in Example 1 a
stabilizing layer was coated in a ratio of 152 ml per sq.m
with the following composition : 50 ml of a 20 % polyvinyl
acetate solution in methanol and 50 ml of a 12 % tritolylsti-
bine solution-in benzene.
~ fter drying, this material was image-wise exposed as
described in Example 1 and heated for 40 s at 130C. A stable
image was obtained.
Example 5
On the same imaging layer as described in Example 1 a
GV.781 PC~
1054839
stabilizing layer was coated in a ratio of 152 ml per sq.m
with the following composition : 50 ml of a 20 % cellulose
nitrate solution in methanol and 50 ml of a 10 % diphenyl-
selenide solution in methanol.
After drying, this material was image-wise exposed as
described in Example 1 and heated for 40 s at 130C. A
light-stable image was obtained.
Exampl~ 6
On the same imaging layer as described in ~xample 1 a
stabilizing layer was coated in a ratio of 152 ml per sq.m
with the following composition : 50 ml of a 30 % ethylcellu-
lose solution in ethanol and 50 ml of a 12 % propene-3-nitrile
solution in ethanol.
After drying, this materlal was ima~e-wise exposed as
described in Example 1 and heated for 40 s at 130C. A
light-stable image was obtained.
_xample 7
On the same imaging layer as described in Example 1 a
stabilizing layer was coated in a ratio of 152 ml per sq.m
with the following composition : 50 ml of a 20 % polyvinyl
acetate solution in ethanol and 50 ml of a 10 % triphenyl-
phosphine solu-tion in methanol.
After drying, this material was image-wise exposed to
U.V. radiation and heated for 40 s at 130C. A stable
image was obtained.
xample 8
A polyethylene terephthalate support of a thickness of
GV.781 PC~ - 12 -
1i354B39
0.10 mm was coated in a ratio of 76 ml per sq.m with the fol-
lowing composition : 50 ml of a 10 % phenolic resin solu-
tion in methanol and 50 ml of a 8 % triphenylstibine solution
in e~thylene glycol monomethyl ether. On this stabilizing
layer a light-sensitive layer of the composition of ~ayer
A of Exa~ple 1 was coated but in a ratio of 152 ml per sq.m.
After drying, this material was exposed to~U.V. radiation
and heated at 130C for 2 min. A stable image was obtained.
ExamPle 9
A polyethylene terephthalate support of a thickness of
0.10 mm was coated in a ratio of 152 ml per sq.m with the
following composition : 12 parts of ~,d,~-tribromoquinoxa-
line-2, 12 parts of 3-methyl-di-~ -naphthospiropyran, 50 parts
of poly-N-vinylcarbazole, 1 pa~t of silicone oil, dissolved
in 1446 parts of trichloroethylene and 1336 parts of methylene
chloride.
On top of this imaging layer a stabilizing layer was
coated in a ratio of 76 ml per sq.m. with the following compo-
sition : 50 ml of a 10 % triphenylstibine solution in ethylene
glycol monomethyl ether and 50 ml of a 10 % ethylcellulose
solution in methanol.
After drying, this material was exposed to U.V. radiation
and heated for 4 s at 140C. A light-stable image was obtained.
Example 10
A polyethylene terephthalate support of a thickness of
0.10 mm was coated in a ratio of 152 ml per sq.m with the
GV.781 PC~ - 13 -
1054839
following composition : 15 parts of carbon tetrabromide, 15
parts of iodoform, 15 parts of 3-methyl-di-~-naphthospiropy-
ran as dye precursor, 1.5 part of Michler's ketone, 50 parts
of polystyrene, dissolved in 1446 parts of trichloroethylene
and 1336 parts of methylene chloride.
On top of this imaging layer a stabilizing layer was
coated in a ratio of 76 ml per sq.m with the following com-
position : 50 ml of a 10 % triphenylstibine solution in
ethylene glycol monomethyl ether and 50 ml of a 10 %iethyl-
cellulose solution in methanol.
After drying, this material was exposed to U.V. radia-
tion and heated for 3Q s at 130C. A light-stable image was
obtained.
A polyethylene teréphthalate support of a thick~ess of
0.10 mm was coated in a ratio of 152 ml per sq.m with the
following composition : 20 parts of carbon tetrabromide,
25 parts of 4-p-dimethylaminostyrylquinoline as dye precur-
sor, 50 parts of polystyrene, dissolved in 1446 parts of
trichloroethylene and 1336 parts of methylene chloride.
On top of this imaging layer a stabilizing layer was
coated in a ratio of 76 ml per sq.m with the following com-
position : 50 ml of a 10 % triphenylstibine solution in
ethylene glycol monomethyl ether and 50 ml of a 10 % ethyl-
cellulose solution in methanol.
After drying, this material was exposed to U.V. radi-
ation and heated for 1 min at 130C. A light-stable image
was obtained.
GN.781 PCl - 14 -
1054839
Example 12
On the same imaging layer as described in Example 1 a
stabilizing layer was coated in a ratio of 50 ml per sq.m
with the following composition : 35 ml of a 10 % pol~vinyl-
butyral solution in methanol, 10 ml of ethylene glycol mono-
méthyl ether and 35 ml of a 5 % by weight solution in toluol
of compound * of Table 2.
After drying, this material was exposed to U.V. radia-
tion, as described in Example 1, and heated for 60 s at
130C. A light-stable image was obtained.
Example 13
On the same imaging layer as described in Example 1
a stabilizing layer was coated in a ratio of 76 ml per sq.m
with the fol~owing composition : 40 ml of a 10 % polyvinyl-
butyral solution in methanol, and 40 ml of a 5 % by weight
solution in toluol of triphenylamine.
After drying, this material was exposed to U.V. radia-
tion, as described in Example 1, and heated for 60 s at
130C. A light-stable image was obtained.
Example 14
On the same imaging layer as described in Example 1
a stabilizing layer was coated in a ratio of 50 ml per sq.m
with the following composition : 40 ml of a 10 % polyvinyl-
butyral solution in methanol, and 40 ml of a 5 % by weight
solution in ethylene glycol monomethyl ether of compound
6 of ~able 2.
GV.781 PCT - 15 -
~054839
After drying, this material was exposed to U.V. radia-
tion, as described in Example 1, heated for 45 s at 130C.
A light-stable image was obtained.
GV.781 PCT - 16 -
