Note: Descriptions are shown in the official language in which they were submitted.
-- 1 --
HEAT-SENSITIVE RECORDING UNIT
This invention relates to a novel heat-sensitive
recording unit making use of production of a color by a
novel oxidation-reduction reaction., More specifically, it
relates to a heat-sensitive recording unit comprising, as
.
5 essential components, a methine-type chromogenic reactant
and an oxidizing organic compound supported on a base.
A variety of methods has heretofore been proposed
as to the heat-sensitive recording system which provides
a record of images or marks by utilizing a physical or chemical
change that a substance undergoes under the influence of
thermal energy. Among these heat-sensitive recording methods,
the so-called chromogenic reactant based color production-
type heat-sensitive recording method and heat-sensitive
recording paper making use of the recording method, which
are proposed in Japanese Patent Publication No. 14039/1970,
etc., have found wide-spread commercial utility in output
console units such as computer, console units and facsimiles,
reflecting recent technical advancement in thermal printers
led by the development of thermal heads making use of resistor
elements, because the above particular heat-sensitive recording
.
method is free of such problems as noise and offensive odor
and it permits high-speed recording. Accordingly, the
chromogenic reactant based color production-type heat-
sensitive recording method and heat-sensitive recording
paper which makes use of the above recording method are
expected to find still more acceptance in the future.
These chromogenic reactant based color production-
type heat-sensitive recording paper are each formed, generally
speaking, of (A) a lactone-type chromogenic reactant, for
example,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthaltide
(crystal Violet Lactose) and (B) an acidic substance, for
example, a finlike compound such as 2-bis(4-hydroxyphenyl)-
propane (bisphenol A), which are supported together with a
binder and other additives on a base. An application of
heat causes at least one of the reactants (A) and (B) to
melt and the reactants (A) and (~) are hence allowed to
contact with each other, thereby forming a color image or
mark with the thus-acidified lactone-type chromogenic reactant
on the base.
Heat-sensitive recording paper making use of
the color production by the contact of a lactone-type
chromogenic reactant and an acidic finlike compound is
however accompanied by the following serious problems:
(1) It is necessary to Corey chromogenic reactant
and its matching color-developing agent both in large amounts
on a base if one wants to obtain a color image or mark having
.
. _ . . . . .
-- 3
sufficient density. A lot of energy is thus required to
melt either one or both of the chromogenic reactant and
color-developing agent so as to bring them into mutual
contact, thereby making the heat-sensitive recording paper
difficult to meet the recent trend toward still faster
recording in data communication (facsimiles); and
(2) Color images or marks, which are obtained by
the reaction between an chromogenic reactant and color-developing
agent when either one or both of the chromogenic reactant and
color-developing agent are melted by heat, are extremely
unstable and are susceptible of undergoing easy discoloration
or fading upon exposure to light, whereby making the color
images or marks unlegible. Furthermore, such color images
or marks readily disappear upon contact with an oil or the
like.
There it a strong outstanding demand for the
improvement to these problems in the above heat-sensitive
recording method which is expected to become the dominant
method in facsimiles which have been finding more and more
acceptance in recent years. A variety of extensive researches
and investigations have been made in recent years with
respect to chromogenic reactants, color-developing agents,
additives and coating formulations for heat sensitive recording
paper. Under the circumstances, none of such researches and
investigations appear to have resulted in any breakthrough
improvement.
-- 4
In accordance with the present invention, there is
provided a heat-sensitive recording unit comprising a
methine-ty~e.chromogenic reactant represented by the
following general formula (I):
Y
X-CH-Z (I)
wherein X, Y and Z may be the same or different and mean
individually a substituted or unsubstituted phenol, naphthyl,
stroll or aromatic heterocyclic residual group, two of X,
Y and Z may be coupled together to form a ring, and the
substituted or unsubstituted phenol, naphthyl or stroll
group has at least one amino, substituted amino or lower
..
alkoxyl group at the para-position relative to the central
methane group of the molecule when one or none of X, Y and
Z is the aromatic heterocyclic residual group and an oxidizing
organic compound, both, supported on a base.
The above heat-sensitive recording unit is totally
different from conventional color systems which relied upon
acid-base reactions between lactone-type chromogenic reactants
and acidic substances and has solved the above-described
various problems ox conventional heat-sensitive recording paper
of the chromogenic reactant based color production type.
The main feature of the heat-sensitive recording
unit according to this invention resides in that, although
conventional heat-sensitive recording units provide or form
color images or marks by the equilibrium reactions between
acids (acidic color-developing agents represented by bisphen`ols)
and bases (lactone-type chromogenic reactants led by CAL),
i.e., in accordance with the following chemical equation:
Acidic color-developing agent
+ Color images or marks,
Basic chromogenic reactant
the heat-sensitive recording unit of this invention makes
use of an oxidation-reduction reaction which is considered to
proceed substantially in a non-reversible fashion, namely,
which is expressed as follow:
Oxidizing organic color-
developing agent
+ ? Color images or marks
Methine-type chromogenic
reactant
.
In the heat-sensitive recording unit according to this
invention, color images or marks formed on the base thereof
by heating the unit and allowing the reactants to contact
.
with each other are extremely stable to the environment.
Methine-type chromogenic reactants useful in the
present invention are a group of compounds represented by
the above general formula (It s illustrative aromatic
heterocyclic residual groups represented by X, Y and/or Z,
may be mentioned those having the following basic structures:
I', ~.~.
It should however be borne in mind that the aromatic:.heterocyclic
residual groups are snot limited to those given above
In addition, as substituent groups which may be
bonded to carbon and/or hotter atoms of the phenol, naphth.yl,
stroll or aromatic heterocyclic residual group, may, for
example, be mentioned halogen atoms; lower alkyd groups;
halogenated lower alkyd groups; cycloalkyl groups; lower
k~J
~LZ~5~
alkoxy groups; azalea group; carboalkoxy groups; cyanoalkyl
groups; cyan group; hydroxyl group; vitro group; substituted
or unsubstituted aralkyl~, phenol, airlocks, aralkylalko~y and
amino groups; substituted amino groups containing, as subset-
tent group or groups, one or two lower alkyd, cycloalkyl,
cyanoalkyl, halogenated alkyd, hydroxyalkyl, substituted-or
unsubstituted aureole, or substituted or unsubstituted aralkyl
groups; polymethyleneamino groups (for example, pyrrolidino
and piperidino groups); and morpholino group. Two of such
substituent groups may be coupled together to form a ring.
Specifically speaking, the following compounds
may be mentioned:
(A) Triaminotriphenylmethane-type chromogenic reactants:
4,4',4"-tris-dimethylamino-triphenylmethane;
4,4',`4"-tris-diethylamino-triphenylmethane;
4,4'-bis-methylamino-4"-dimethylamino-
triphenylmethane;
4,4'-bis-dimethylamino-4"-methylamino-
triphenylmethane;
4,4'-bis-diethylamino-4"-ethylamino-
triphenylmethane;
4,4'-bis-diethylamino-4"-amino-triphenylmethane;
4,4'~bis-dimethylamino-3"-methyl-4'-amino-
triphenylmethane;
4,4'-bis-dimethylamino-3"-me.thyl-4"-methylamino-
triphenylmethane;
4,4',4"-trisphenylamino-triphenylmethane;
4,4',4"-tris(N-methyl-N'-phenylamino)-triphenyl-
methane;
.. . .
I21~
- 8 -
4,4'~bismorpholino-4"-dimethylamino-
triphenylmethane;
4,4',4"-tris-dimethylamino-2,2'-dimethyl-
triphenylmethane;
4,4',4"-tris-dimethylamino 3,3'-dimethyl-
triphenylmethane;
4,4',4"-tris-dimethylamino-2-methoxy-
triphenylmethane;
4,4',4"-tris-dimethylamino-3-methyl-
triphenylmethane;
4,4'-bis~dimethylamino-4"-N-benzylamino-
triphenylmethane;
4,4'-bis-dimethylamino-4"-N-benzylamino-
3'-methoxytriphenylmethane;
4,4'-bis-dimethylamino-4"-N-benzylamino-
3"-methyltriphenylmethane;
4,4'-bis-dimethylamino-3'-chloro-4'-N-
benzylaminotriphenylmethane;
4,4'-bis-dimethylamino-4"-(N-benzyl-N-methylamino))-
triphenylmethane;
4,4'-bis-dimethylamino-4"-(N-o-chlorobenzyl-N-
methylamino)-triphenylmethane;
4,4'-bis-dimethylamino-4"-(N-p-chlorobenzyl-
N-methylamino)-triphenylmethane;
4,4'-bis-dimethylamino-4"-(N-p-methylbenzyl-
N-methyl)-triphenylmethane;
4,4'-bis-dimethylamino-4"-(N,N-dibenzylamino)-
triphenylmethane;
4,4'-bis-dimethylamino-4"-(N-phenyl-N-methyl-
amino)-triphenylmethane;
4,4'-bis-dimethylamino-4"-morpholino-triphenyl-
methane;
4,4'-bis-N-benzylamino-4"-dimethylamino-
triphenylmethane;
,
- 9 -
4,4'-bis-(N-benzyl-N-methylamino)-4"-dimethyl-
aminotriphenylmethane;
4,4'-bis-(N-parachlorobenzyl-N-methylamino)-
4"-dimethylamino-triphenylmethane;
4,4'-bis(N-parabromobenzyl-N-ethylamino?-4"-
diethylamino-triphenylmethanei
4,4'-bis-pyrrolidyl-4"-dimethylaminotriphenyl-
methane;
4,4'-bis(N-orthochlorobenzyl-N-methylamino)-4"-
dimethylamino-triphenylmethane;
4,4'-bis-pyrrolidyl-4"-(N-benzyl-N-methylamino)-
triphenylmethane;
3,3'-dichloro-4,4'-bis(N-benzylamino)-4"-dimethyl--
amino-triphenylmethane;
4,4'-bis(N-p-methylbenzyl-N methylamino)-4"-dimethyl-
amino-triphenylmethane;
4,4'-bis(N-p-methylbenzyl-N-ethylamino)-4"-
diisopropylamino-triphenylmethane;
3,3'-dimethyl-4,4'-bis(p-methylbenzylamino)-4"- I.
dimethylaminotriphenylmethane;
3,3'-dimethyl-4,4'-bis(N-benzylamino)-4"-
dimethylamino-triphenylmethane,
3,3'-dibutyl-4,4'-bis-N-benzylamino-4"-diethyl-
amino-triphenylmethane
etc.
(B) Diaminotriphenylmethane-type chromogenic reactants:
4,4'-bis-dimethylamino-triphenylmethane;
4,4'-bis-dimethylamino-4"-methyl-triphenylmethane;;
4,4'-bis-(N-benzyl-N-ethylamino)triphenyl-
methane;
4,4'-bis-dimethylamino-2-chloro-triphenylmethane;
4,4'-bisdiisopropylamino-3"-bromotriphenylmethane;;
4,4'-bisdimethylamino-4"-methoxytriphenylmethane;
-- 10 --
4,4'-bisdimethylamino-4"-ethoxytriphenylmethane;
4,4'-bisdimethylamino-3"-methyl-4"-methoxy-
triphenylmethane;
4,4'-bisdimethylamino-3"-methyl-4"-ethoxytriphenyll-
methane;
4,4'-bisdimethylamino-3",4"-dimethoxytriphenyl-
methane;
4,4'-bisdimethylamino-2",4"-dimethoxytriphenyl-
methane;
4,4'-bis-diethylamino-3'-ethyl-4"-etho~y-
triphenylmethane;
4,4'-bis-methylamino-3,3'-dimethyl-3"-butyl-
4"-butoxy-triphenylmethane;
4,4'-bis-dimethylamino-3"-cyclohexyl-4"-methoxy-
triphenylmethane;
4,4'-b.is-propylamino-3"-phenyl-4"-propoxy-
triphenylmethane;
4,4'-bis(N-benzyl-N-methylamino)-3'-propyl-4"-
methoxytriphenylmethane;
4,4'-bis(N-benzyl-N-methylamino)-3"-methyl-4"-
ethoxytriphenylmethane;
4,4'-bis-N-pyrrolidyl-3"-methyl-4"-methoxy-
triphenylmethane;
4,4'-bis-N-piperidyl-3"-methyl-4"-ethoxy-
triphenylmethane;
4,4'-dimethylamino-3"-tert-butyl-4"-methoxy-
triphenylmethane;
etc.
(C) ~onoaminotriphenylmethane-type chromogenic reactants:
4,4'-dimethoxy-4"-dimethylaminotriphenylmethane;
4,4'-dimethoxy-3"-methyl-4"-methylamino-
triphenylmethane;
4,4'-diethoxy-4"-diethylaminotriphenylmethane
....
1 1 r
4,4'~dimethoxy-4'1-(N-benzyl.N-methylamino)-
triphenylmethane,
3,3'-dimethyl-4,4'-dimethoxy-4"-dimethyl-
aminotriphenylmethane;
4,4'-dimethoxy-4"-pyrrolidinotriphenylmethane;
4,4'-dimethyl-4"-diethylaminotriphenylmethane;
4-methoxy-4'-dimethylaminotriphenylmethane;
etc.
(D) Naphthylmethane-type chromogenic reactants:
bis(4-dimethylamino-naphthyl-1)-4-dimethyl-
aminophenylmethane;
bis(4-ethylamino-naphthyl-1)-4'-dimethylamino-
phenylmethane,
bis(4-N-paratolyl-N-methylamino-naphthyl-1)-4'-
isopropylaminophe~ylmethane;
tris(4-dimethylamino-naphthyl-1)methane;
bis(4-dimethylamino-naphthyl-1)-4'-N-morpholino-
phenylmethane;
bis(4-diethylaminophenyl)-4'-~-phenylamino-
naphthyl-l'-methane;
bis(4-diethylami~ophenyl)-4'-ethylaminonaphthyl-
methane
bis(4-N-phenyl-N-methylaminonaphthyl-l)-~-styryl-
methane;
bis(4-dimethylamino-naphthyl-1)-p-chlorostyryl-
` methane;
bis(4-dimethylaminophenyl)-2'-methoxynaphthyl-1'-
methane;
bis(4-dimethylaminophenyl)-4'-methoxynaphthyl-
methane
bis(4-dimethylaminophenyl)-naphtyl-2'-methane;
bis(4-N-propylaminophenyl)-4'-propo~ynaphthyl-
2-methane;
-. - 12 -
bis(4-dimethylaminonaphthyl~ 2'-pyridylmethane;
bis(4-dimethylaminonaphthyl-1)-2'-pyrazylmethane;
bis(4-dibenzylaminonaphthyl-1~-quinolin~3'-yl-
methane;
etc.
(E) Diphenyl-g-styrylmethane-type chromogenic reactants:
bis(4-dimethylaminophenyl)-~-styrylmethane;
bis(3-methyl-4-N-phenylaminophenyl)-~-styrylmethanno;
bis(4-N-~enzyl-N-methylaminophenyl)-~-styrylmethanno,
bls(4-dimethylaminophenyl)-B-(4'-dimethylamino-
styryl)methane;
bis(4-dimethylaminophenyl)-B-(4'-methoxystyryl)metthan;
bis(4-diethylaminophenyl)-B-(3'-methyl-4'-
ethoxystyryl)methane;
bis(3-methyl-4-ethox~phenyl)-g-(4'-diethyl-
aminostyryl)-methane;
4-methylphenyl-4'-diethylaminophenyl-B-(3'-
tert-butyl-4'-dimethylaminostyryl)-methane;
etc.
(F) Indolylmethane-type chromogenic reactants:
phenyl-bis(l-ethyl-2-methyl-indol-3-yl)methane;
4-methoxyphenyl-bis(l'-ethyl-2'-methylindol-3'-
yl)methane;
3-methyl-4-methoxyphenyl-bis(l'-ethyl-2'-
methylindol-3i-yl)methane;
3,4-dimethoxyphenyl-bis(l'-ethyl-2'-methyl-
indol-3'-yl)methane;
2,4-dimethoxyphenyl-bis(l'-ethyl-2'-methyl-
indol-3'-yl)methane;
3,4-diethoxyphenyl-bis(l'-ethy]-2-methylindol~
` 3'-yl)methane;
. .
. .
- 13 -
3-butyl-4-methoxyphenyl-bis~ bottle'-
methylindol-3'-yl)methane;
4-ethoxyphenyl-bis(l'-ethyl-2'-phenylindol-
3'-yl)methane;
4-ethoxyphenyl-bis(l'-ethyl-2'-methylindol-
3'-yl)methane;
phenyl-bis(l'-n-butyl-2'-methylindol-3'-yl)methanee;
phenyl-bis(l'-methyl-2'-phenylindol-3'-yl)methàne;;
bis-(4-dimethylaminophenyl)-1'-ethyl-2'-methyl-
indol-3'-yl)methane;
bis(l-ethyl-2-methylindol-3-yl)-2'-naphthylmethanee;
bis(l-ethyl-2-methylindol-3-yl)-1'-naphtylmethane;;
tris(l-ethyl-2-methylindol-3-yl)methane;
tris(l-n-butyl-2-methylindol-3-yl)methane; -
bis(l-ethyl-2-methylindol-3-yl)-3'-chloro-4'-
methoxyphenylmethane;
bis(l-propyl-2-phenylindol-3-yl)phenylmethane;
bis(l-octyl-2-methylindol-3-yl)phenylmethane;
bis(l-benzyl-2-methylindol-3-yl)phenylmethane;
bis(l-ethyl-2-methylindol-3-yl)-2'-methylphenyl-
methane;
bis(l-ethyl-Z-methylindol-3-yl)-3'-methylphenyl-
methane;
bis(l-ethyl-2-methylindol-3-yl)-4'-methylphenyl-
methane;
bis(l-ethyl-2-methylindol-3-yl)-2'-methoxyphenyl-
methane;
bis(l-ethyl-2-methylindol-3-yl)-41-f].uorophenyl-
methane;
bis(l-ethyl-2-methylindol-3-yl)-4'-bromophenyl-
methane,
bis(l-hexylindol-3-yl)phenylmethane;
- 14 - -
bis(l-ethyl-2-methylindol-3-yl)-3'-nitrophenyl-
methane;
bis(l-ethyl-2-methylindol-3-yl)-3',4'-dichloro~
phenylmethane;
bis(l-ethyl~2-methylindol-3-yl)-2'-thienylmethane;;
bis(l-ethyl-2-methylindol-3-yl)-4'-methyl-2'~
thienylmethane;
bis(l-butyl-2-methylindol-3-yl)-4'-pyridylmethane;;
etc.
(F) Other leucomethine-type chromogenic reactants:
3,6-bis-dimethylamino-9-phenylxanthene;
: 3,6-bis-diethylamino-9-phenylxanthene;
3,6-bis-dimethylamino-9-(3'-me~hyl-4'-dimethyl-
aminophenyl)xanthene;
3-diethylamino-6,7-dimethyl-9~phenylxanthene;
3,6-dimethoxy-9-(4'-dimethylaminophenyl)xanthene;
3,6-diethoxy-9-(4'-dimethyl-naphthyl-l')xanthene;
3,6-bis(N-methyl-N-phenylamino)-9-(3',4'-
dimethoxyphenyl)xanthene;
3,6-bis-dimethylamino-9-phenylthioxanthene;
3,6-dimethylamino-9-(4'-methoxydiphenyl)-10-
methyl-9,10-dihydroacridine;
3,6-bisdimethylamino-9-(4'-dimethylmaino-
phenyl)fluorene;
etc.
It should however be borne in mind that the methane-
type chromogenic reactant useful in the practice of this
invention is not necessarily limited to the above-recited
illustrative compounds.
On the other hand, the oxidizing organic compound
-- 15 --
useful in the practice of this invention means such an
oxidizing organic compound that, when either one or both of
the chromogenic reactant and oxidizing organic compound are
molten owing to an application of heat thereto, it is
brought into contact with the methine-type chromogenic
reactant and oxidizes the methine-type chromogenic reactant,
thereby providing a color image or mar with the thus-o,~idized
methine-type chromogenic reactant on the base. As preferred
compounds, may be mentioned quinine derivatives which have
oxidizing capacity and are practically insoluble in water.
More preferably, may be mentioned water-insoluble quinine
derivatives which have each been substituted by an electron-
attractive group. Queen derivatives substituted by an electron-
attractive group, notably multi-substituted by a plurality
of electron-attractive groups are compounds having high
oxidation-reduction potentials and are of the most preferable
compound forms.
Since these quinine derivatives are required to be
present in a stable state on heat-sensitive recording paper,
it is not preferred to use compounds having low molecular
weights or those having sublimely property More specifically,
it is preferred to use benzoquinone derivatives represented
by the general formula (II) or (III):
I X 1 R4 I O
R2 R3 R7
O R8
(II) IT
- 16 -
in which at least one of Al - I which aye individually a halogen
atom or a cyan, nltro, carboxyl,- alkoxycarbonyl, aryloxycarbonyl,
aralkyloxycarbonyl, alkylsulfonyl, arylsulfonyl, aralkylsulfonyl,
alkoxysulfonyl, aryloxysulfonyl, aralkyloxysulfonyl or azalea group
is contained as substituent group(s) in the molecule and the remaining
substituent group(s) is individually a hydrogen atom or an allele,
aureole, aralkyl , alkoxy, airlocks, aralkyloxy, alkylthio or arylthio
group and where the adjacent carboxyl groups may form an imide
ring.
As exemplary benzoquinone derivatives represented
by the general ormolu IT or (III), may be mentioned:
2,3-dicyano-5,6-dichloro-1"4-benzoquinone;
2,3,5,6-tetracyano-1,4-benzoquinone;
3,4-dibromo-.5,6-dicyano-1,2-benzoquinone;
3,4,5,6-tetr.acyano-1,2-benzoquinone;
2,3,5,6-tetrabromo-1,4-benzoquinone;
2,3,5,6-tetraiodo-1,4-benzoquinone;
2,3,5,6-tetramethoxycarbonyl-1,4-benzoquinone;
2,3,5,6-tetraethoxycarbonyl-1,4-benzoquinone;
2,3,5,6-tetra-i-butoxycarbonyl-1,4-benzoquinone;
2,3,5,6-tetra-n-hexyloxycarbonyl-1,4-benzoquinone;;
2,3,5,6-tetra-(2'-ethylhexyloxycarbonyl)-1,4-
benzoquinone;
2,3,5,6-tetradodecyloxycarbonyl-1,4-benzoquinone;
2,3,5,6-tetraphenoxycarbonyl-1,4-benzoquinone;
Jo 2,3,5,6-tetra-p-toluyloxycarbonyl-1,4-benzoquinonee;
- ~L5~q
2,3,5,6 tetrabenzyloxycarbonyl-1,4-benzoquinone;
2,3,5,6-tetranaphthoxycarbonyl-1,4 benzoquinone;
3,4,5,6-tetrapropyloxycarbonyl-1,2-benzoquinone;
3,4,5,6-tetra-n-butoxycarbonyl-1,2-benzoquinone,
2,5-dimethoxycarbonyl-3,6-dichloro-1,4-benzoquinonno;
2,5-diethoxycarbonyl-3,6-dibromo-1,4-benzoquinone
2,5-di-i-butoxycarbonyl-3,6-dibromo-1,4-benzo-
quinine;
2,5-di-n-octoxycarbonyl-3,6-dibromo-1,4-benzo-
quinine;
2,5-diphenoxycarbonyl-3,6-dliodo-1,4-benzoquinone;;
2,5-dibenzyloxy-3,4-dichloro-1,2-benzoquinone;
3,6-di-n-pentyloxycarbonyl-3,4-dichloro-1,4-
benzoquinone;
2`,5-dibenzyloxycarbonyl-1,4-benzoquinone;
2,5-dibenzoyl-3,6-dichloro-1,4-benzoquinone;
2,5-dibenzoyl-3,6-dibromo-1,4-benzoquinone;
2,5-dibenzoyl-3-bromo-1,4-benzoquinone;
2,5-diacetyl-3,6-dibromo-1,4-benzoquinone;
2,5-diethoxycarbonyl-3,6-diphenylsulfonyl-
1,4-benzoquinone;
2,5 di-n-butoxycarbonyl-3,6-di-4'-tolylsulfonyl-
1,4-benzoquinone;
2,5-di-n-hexyloxycarbonyl-3,6-diphenylsulfonyl-
1,4-benzoquinone;
2,5-di-i-propylox~carbonyl-3,6-di-p-tolylsulfonyl--
1,4-benzo~uinone;
2,5-di-i-butoxycarbonyl-3,6-di-p-cyclohexylphenyl--
sulfonyl-1,4-benzoquinone;
2,5-di-(2'-ethylhexyloxycarbonyl)-3,6-di-4'-
diphenylsulfonyl-1,4-benzoquinone;l
,
- 18 -
2,5-di-n~propyloxycarbonyl-3,6-di-4'-chlorophenyl--
sulfonyl-1,4-benzoquinone;
2,5~diethoxycarbonyl-3,6-di-4'-methoxyphenyl-
sulfonyl-1,4-benzoquinone;
2,5-di-benzyloxycarbonyl-3,6-di-4'-tolylsulfonyl-
1,4-benzoquinone;
2,5-di-n-octyloxycarbonyl-3,6-diethylsulfonyl-
1,4-benzoquinonei
2,5-diethoxycarbonyl-3,6-(2'-naphthylsulfonyl)-
1,4-benzoquinone;
2,5-dimethoxycarbonyl-3-toluylsulfonyl-1,4-
benzoquinone;
3,6-diethoxycarbonyl-4,5-diphenylsulfonyl-1~2
benzoquinone;
2,3,5,6-tetra-4'-toluylsulfonyl-1,4-benzoquinone;
2,3,5,6-tetraphenylsulfonyl-1,4-benzoquinone;
2,3,5,6-tetraethylsulfonyl-1,4-benzoquinone;
3,4,5,6-tetra-i-butylsulfonyl-1,2-benzoquinone;
2,3,5,6-tetra-n-octylsulfonyl-1,4-benzoquinone;
2,3,5,6-tetrabenzyloxysulfonyl-1,4-benzoquinone;
2,5-di-n-propyloxycarbonyl-3,6-dibenzoyl-1,4-
benzoquinone;
2,5-di-i-butoxycarbonyl-3-benzoyl-1,4-benzoquinonee;
2,3-dichloro-1,4 benzoquinone-5,6-dicarboxylic
butylimide;
1,4-benzoquinone-2,3,5,6-tetracarboxylic diphenyl-
imide;
1,2-benzoquinone-3,4,5,6-tetracarboxylic di-n-octyl-
imide;
2,5-diethoxysulfonyl-1,4-benzoquinone;
2,5-diphenoxysulfonyl-3,6-dichloro-1,4-benzoquinonno;
-- 19 --
2,5-di-n-butoxycarbonyl-3,6-dibutoxysulfonyl-
1,4~benzoquinone;
Z,S-di-p-toluylsulfonyl-3,6-dibromo-1,4-benzoquinoone;
2,5-di-n-hexylsulfonyl-3,~-dichloro-1,4-benzoquinoone;
2,5-dibenzoyl-1,4-benzoquinone;
2,5-di(4'-methylbenzoyl)-1,4-benzoquinone;
2,5-di(4'-ethylbenzoyl)-1,4-benzoquinone;
2,5-di(3',4'-dimethylbenzoyl)-1,4-benzoquinone;
2,5-di(4'-chlorobenzoyl)-1,4-benzoquinone;
2,5-di(p-bromobenzoyl)-1,4-benzoquinone;
2,5-di(2',5'-dichlorobenzoyl)-1,4-benzoquinone;
etc.
Among the above-described benzoquinone derivatives,
2,5-dibenzoyl-1,4-benzoquinone derivatives represented by the
general formula IVY): no
no O
wherein R means a hydrogen or halogen atom or a lower alkyd
group, and n stands for an integer up to 3 are particularly
preferred due to their excellent storage stability, light
resistant stability and anti-solvent stability. 2,5-Dibenzoyl-
1,4-benzoquinone is the most suitable compound because its
raw materials are easy to obtain and are easy to handle during
its synthesis.
Even if a quinine derivative has great oxidizing
capacity and has been substituted by one or more electron-
,~34~-~
- 20 -
attractive groups, the quinine derivative such as 2,3,5,6-
tetrachloro-1,4-benzoquinone(Chloroanil), 2,3,5,6-tetrafluoro-
1,4benzoquinone(Fluoroanil),2,3,5-trichloro-1,4-benzooquinone,
dichlorobenzoquinone, difluorobenzoquinone, eta, cannot be used
as is for the following reasons where it has a small molecular
eight and is sublimable:
(1) It undergoes gradual sublimation from the
heat-sensitive recording paper during its storage and the
color-producing capacity of the heat-sensitive recording
paper is thus lowered
2) The thus-sublimated quinine derivative reacts
with the methine-type chromogenic reactant, thereby causing
the heat-sensitive recording paper to show an undesired or
inconvenient color which is the thus-oxidized methine-type
chromogenic reactant; and ..
(3) The working environment is adversely affected.
._ .
Accordingly, it is necessary to use some sublimatlon-suppressing
means if one wants to employ such a quinine derivative as is.
The methine-type chromogenic reactant useful in
the practice of this invention and represented by the general
formula (I) is generally unstable to its storage and, in
many instances, tends to show such tendency that it considerably
colors an aqueous suspension, aqueous coating formulation or
the coated surface of a heat-sensitive recording paper respect
lively in its dispersion step in a liquid (i.e., the step to
- 21 -
convert the methine-type chromogenic reactant to the aqueous
suspension in which the reactant is present as fine particles),
in the preparation step of the methIne-type chromogenic reactant
together with a color-developing agent and other additives
into the aqueous coating formulation or in the coating step
of the aqueous coating formulation on a base to prepare the
heat-sensitive recording paper; and the resulting heat-sensitive
recording paper is colored during its storage or upon exposure
to light. Therefore, the methine-type chromogenic reactant
Milwaukee utility in some instances, in the production of
heat-sensitive recording paper if it is used as is.
Accordingly, it is preferred to use (A) a qua ternary
ammonium salt, (B) an alkanol amine having a tertiary amino
group or (C) a water-soluble metal ion sequestering agent along
with the methine-type chromogenic reactant and oxidizing
organic compound which are basically essential in the present
invention.
As exemplary qua ternary ammonium sells, may
- be mentioned specifically:
lauryltrimethylammonium chloride;
stearyltrimethylammonium chloride;
distearyldimethylammonium chloride;
dodecyltrimethylammonium chloride;
octadecyltrimethylammonium chloride;
tetradecyldimethylbenzylammonium chloride;
etc.
- 22 - -
As specific examples of the alkanol amine containing
a tertiary amino, may be mentioned:
tris-N-(2-hydroxyethyl)amine;
tris-N-(2-hydroxypropyl)amine;
tris-N-(3-hydroxypropyl)amine;
tris-N-(hydroxydibutyl)amine;
N,N-dimethyl-N-(2-hydroxyethyl)amine;
N,N-diethyl-N-(2-hydroxyethyl)amine;
N,N-dipropyl-N-(2-hydroxyethyl)amine;
N,N-dibutyl-N-(2-hydroxyethyl)amine;
N-methyl-N-phenyl-N-(2-hydroxyethyl)amine;
N,N-diphenyl-N-(2-hydroxyethyl)amine;
N,N-dimethyl-N-(2-hydroxypropyl)amine;
N,N-diethyl-N-(2-hydroxypropyl)amine;
N,N-dipropyl-N-(2-hydroxypropyl)amine;
N,N-dibutyl-N-(2-hydroxypropyl)amine;
N,N-diphenyl-N-(2-hydroxypropyl)amine;
N-methyl-N,N-di(2-hydroxyethyl)amine;
N-ethyl-N,N-di(2-hydroxyethyl)amine;
N-phenyl-N,N-di(2-hydroxyethyl)amine;
N-methyl-N,N-di(2-hydroxypropyl)amine;
N-acetyl-N,N-di(2-hydroxyethyl)amine;
N-methyl-N,N-di(2-hydroxypropyl)amine;
N-acetyl-N,N-di(2-hydroxyethyl)amine;
N-acetyl-N,N-di(2-hydroxypropyl)amine;
N-hydroxyethylmorpholine;
- 23 -
N-hydorxypropylmorpholine;
N-tetradecyl-N,N-di(~-hydroxyethylpolyoxyethylene))-
amine
N-dodecyl-N,N-di(~-hydroxyethylpolyoxye-thylene)ammine;
N-octadecyl-N,N-di(~-hydroxyethylpolyoxyethylene)--
amine;
N,N-didodecyl-N-(~-hydroxyethylpolyoxyethylene)amiire;
N,N-di(cis-octadecenyl)-N-(~-hydroxyethylpolyoxy-
ethylene amine
N,N-dioctadecyl-N (~-hydroxyethylpolyoxyethylene)-
amine
compounds formed by adding alkaline dioxides to
aliphatic dominoes, for example, those represented
by the following structural formula:
(CH2CH20)zH (CH2cH2o)xH
R-N-CH2-CH2-CH -N
\(CH2CH20)y}I
wherein R is an aliphatic chain and x, y and z
are each a positive integer;
N,N-~-hydroxyalkylpolyoxyalkylene-substituted aliphatic
asides, for example, those represented by the
following structural formula:
ill ( CH2CH20 ) oh
(CH2CH20)yH
wherein R means an aliphatic chain and x and y
stand individually for a positive integer;
reaction products between ammonia and glycidols
(2-amino-propylene glycol derivatives);
etc.
The metal ion sequestering agent is bonded with
multivalent metal ions present in a system dispersing the
Jo
- 24 -
chromogenic reactant, i.e., the layer of the chromogenic
reactant applied on the hose of a heat-sensitive recording
paper so as to form a stable chelates compound, thereby
retarding the inconvenient coloring tendency of the methane-
type chromogenic reactant in the presence of such multivalent
metal ions. As metal ion sequestering agents having such
an effect, may for example be mentioned water-soluble metal
ion sequestering agents such as ethylenediaminetetraacetic
acid, N-hydroxyethyl-ethylenediamine-N,N',N'-triacetic acid,
diethylenetriamine-pentaacetic acid, triethylenetetrammine-
pentaacetic acid, nitrilotriacetic acid, N-hydroxyethyl-
iminodiacetic acid, diethanol Gleason, ethylenediamine-N,N'-
diabetic acid, glycolether-diaminetetraacetic acid, 1,3-
diaminopropan-2-ol-tetraacetic acid, tartaric acid, citric
acid, gluconic acid and saccharin acid , and their alkali
metal salts, salts of polyacrylic acid, and metal salts of
ligninsulfonic acid.
These coloration-inhibitory additives may be used
in an amount of 0.1 - 1000 parts by weight per 100 parts by
weight of the methine-type chromogenic reactant. Among
these additives, the water-soluble qua ternary ammonium
sell can bring about the greatest effect when used even
in a relatively small amount.
The heat-sensitive recording unit according to this
invention is basically formed of a methine-type chromogenic
reactant and oxidizing organic compound, both supported as
. .
- 25 -
mutually-isolated wine particles on a base. Accordingly,
the production of a color by the reaction between the methane-
type chromogenic reactant and oxidizing organic compound is
allowed to take place upon application of heat energy that
raises either one or both of the methine-type chromogenic
reactant and oxidizing organic compound to its melting point
or their respective melting points. Therefore, it is required
to have heat-sensitive recording paper produce its color at an
elevated temperature where the chromogenic reactant and/or
oxidizing organic compound, notably, the oxidizing organic
compound is a high mop. compound. Consequently, a heavy load
is applied to thermal heads or heat pens which are used as
sources for supplying thermal energy. Such heat-sensitive
recording paper can hardly meet the high-speed printing. It
is thus preferred to adjust the color-producing temperature
characteristics by using a color production sensitivity regulator
in combination.
In the case of high mop. compounds such as buoyancy-
unwon derivatives which are particularly-preferred oxidizing
organic compounds, for example, 2,5-dibenzoyl-1,4-benzoquinones,
it is preferred to use a color production temperature adjusting
agent in combination.
As such color production sensitivity regulators,
there are employed compounds which have melting points in
the range of 70 - 150 C and, when molten, dissolve the
methine-type chromogenic reactant and/or oxidizing organic
I
- 26 -
compound. As specific compounds, may for example be mentioned
as follows:
(1) Higher fatty acid asides and their derivatives, for example,
Starkey acid aside, linoleic acid aside, myristic acid aside and
oleic acid aside and their methylol derivatives, ethylene-
bis-stearoamide, and ethylene-bis-stearoamide;
(2) alkylbiphenyls, alkylnaphthalenes and biphenylalkanes,
e.g., 4,4'-dimethylbiphenyl, 2,6-diisopropylnaphthalene, etc.;
(3) kittens, for example, diundecyl kitten, diheptadecyl
kitten, etc.;
(4) Carboxylic and sulfonic acid esters of phenol derivatives,
for example, diphenyl preappoint, diphenyl cyclohexylcarboxylate,
diphenyl phenylsulfonate, diphenyl bonniest, knothole bonniest,
p-cyclohexylphenyl bonniest, p-cyclohexylphenyl Tulane
sulfonate, p-cyclohexylphenyl cinnamate, p-tert-butylphenyl
bonniest, p-tert-octylphenyl bonniest, p-acetylphenyl bonniest,
resorsine dibenzoate, 4,4'-thiobisphenol dibenzoate, bus-
phenol A-di(phenylsulfonate), phenyl-p-toluenesulfonate, p-
tert-butylphenyl-p-toluenesulfonate, diphenyl isophthalate,
di-p-sec-butylphenyl isophthalate, di(o-cyclohexylphenyl)
isophthalate, di(o-octoxycarbonylphenyl)isophthalate, dip-
sec-butylphenyl)terephthalate, Dow sec-butylphenyl) lore-
phthalate, and o-phenoxycarbonylphenyl bonniest;
(5) N-phenylsulfonamide derivatives, for example, N-phenyl-
benzenesulfonamide, 4-methyl-N-phenylbenzenesulfonamide, etc.;
(6) aromatic ethers, for example, naphthyl phenol ether;
- 27 -
(7) Aromatic acid asides, or example, benzoic acid N-cyclo-
hexylamide;
(8) Aromatic carboxylic acid esters, for example, dim ethyl
terephthalate; and
(9) Others, including compounds represented by
COO
O H ¦
"COREY
wherein R means a long-chain alkyd group. Needless to say,
the color production sensitivity regulator is not limited to
the above compounds which are merely illustrative.
Among the above-described compounds, the carboxylic
and sulfonic acid esters of phenol derivatives and the N-
phenylsul~onamide derivatives are most effective as color
production sensitivity regulators in heat-sensitive recording
units according to this invention, which units are of the
oxidation color production type. These sensitivity regulators
may be suitably selected in accordance with the desired
temperature and printing speed characteristics of each
heat-sensitive recording paper. The regulator may generally
be used in an amount of 10 - 500 parts by weight per every
100 parts by weight of a color-developing agent. Similar to
the chromogenic reactant and color-developing agent, it is
preferred to form the color production sensitivity regulator
as fine particles into an aqueous suspension in the presence
of a dispersant prior to its application.
-
28 - t
The usual production process of heat-sensitive
recording paper making use of the novel heat-sensitive
- recording unit according to this invention will next be
described.
The methine-type chromogenic reactant represented
by the general formula (I), oxidizing organic compound,
preferably a benzoquinone derivative represented by the
general formula (II), and, if necessary, a color production
sensitivity regulator are separately dispersed as fine particles
in the presence of a surfactant or protective colloidal
substance in water or an organic solvent. As such a surfactant
or protective colloidal substance, may be mentioned polyvinyl
alcohol, carboxymethylcellulose, hydroxyethylcellulose,
methyl cellulose, hydroxycellulose, polyvinyl pyrrolidone,
modified polyvinyl alcohol, gum Arabic gelatin, a high-molecular
anionic surfactant, a natural gum or the like.
These methine-type chromogenic reactant dispersion
(A), color-developing agent dispersion and, if necessary,
color production sensitivity regulator dispersion are then
mixed, followed by further mixing with the above-mentioned
various additives for controlling the physical properties
of the surface of a heat-sensitive recording paper to be
produced. A coating formulation has thus been prepared.
It is also feasible to use, in order to adjust the coat ability
of the coating formulation and the physical properties of
heat-sensitive recording paper to be produced, an inorganic
or organic pigment such as kaolin, calcined kaolin, talc,
- 29 -
titanium oxide, calcium carbonate 7 zinc oxide, aluminum
hydroxide, silica, diatonaceous earth, urea formaldehyde
resin or polystyrene micro beads; a lubricant, for example,
an animal wax such as bees wax or shellac, ~egerable wax
such as carnauba wax, synthetic wax such as petroleum wax,
microcrystalline wax or polyethylene wax, or metal soap
(metal salt of higher fatty acid) such as calcium Stewart
or zinc Stewart; a pressure color production inhibitor;
a binder; a surfactant; a deforming agent; and the like
as needed.
In order to apply the thus-prepared coating
formulation, a variety of coating methods which are known
per so in the art may be employed, including for example the
bar coating method, air-knife coating method, glavure coating
method, flexocoating method, blade coating method, roller
coating method, etc. It is also feasible to incorporate the
coating formulation in paper upon making the paper. It should
be borne in mind that the above mixing method and coating
method do not limit the production process of heat-sensitive
recording paper which makes use of the unit according to this
invention. Thus, it is possible to employ a variety ox coat
worms. or example, the chromogenic reactant and benzoquinone
derivative may be coated respectively as separate layers.
Alternatively, it may be possible to apply an overcoat or under-
coat layer made of a water-soluble polymer material over the
upper or lower surface of a heat-sensitive recording layer
- 30 -
so as to enhance the stability to the environment further.
The general coat weight of the heat-sensitive
layer is at least 0.5 g/m2, and preferably 1 - 10 g/m2 when
measured as a dry coat weight. The relative proportions of
various components making up each heat-sensitive recording
sheet may be as follows:
Methine-type chromogenic 0.5 - 5 wt.%
reactant Preferably, 1 - 3 wt.%
Oxidizing organic 2 - lo White, preferably,
compound 4 - 10 wt.%. -
Color production 0 - 20 wt.%
sensitivity regulator
The coat weights of both chromogenic reactant and
oxidizing organic compound are individually as little as
1/5 1/3 of the phthalide-type compound and acidic I.
finlike color-developing agent which are used most extensively
these days as main components in heat-sensitive recording
paper. Therefore, the heat-sensitive recording paper according
to this invention are extremely advantageous from both
industrial and economical viewpoints.
The heat-sensitive recording unit, which makes use
of the thus obtained novel color production system, enjoys
the following merits compared with conventional chromogenic
reactant based color produciton-type heat-sensitive recording
paper which relies upon a color production reaction between
a phthalide-type or fluoran-type chromogenic reactant and
a finlike compound:
.
I
- 31 - -
1) The amounts of a chromogenic reactant and color-developing
agent, which are applied on a base, have been reduced to
significant extents and there is no need to use the color-
developing agent in any large excess;
2) Since the energy required to produce a color has been
reduced considerably, it is possible to save energy. Besides,
it is feasible to meet the speed-up of the heat-sensitive
recording system, thereby being successfully adopted in the
high-speed facsimile system;
3) Resulting color images or marks feature excellent storage
stability. They do not disappear at all by their contact with
organic solvents. They do not disappear even when brought
Pinto contact with water; and
4) Resulting color images or marks enjoy excellent fastness
to light.
Owing to the above-mentioned merits, the heat-sensitive
recording paper according to this invention is extremely
useful for PUS barricade food Labels which have a big chance
to contact with edible oil, plasticizer contained in PVC wrapping
films, oils and fats contained in foods and plasticizer present
in PVC sheets and in application fields requiring strong
storage stability such as commuting passes, to say nothing of
facsimiles and other printers.
The present invention will hereinafter be described
in further detail by the following examples.
32 -
Example 1:
(A) 2,5-dibenzoyl-1,4~benzoquinone 10 g
(mop. 232 - 235C)
10~ polyvinyl- alcohol 20 g
water 20 g
I
TOTAL 50 g
(B) 4,4',4"-tris-dimethylamino 10 g
phenyl-methane (Luke Crystal
Violet)
10% polyvinyl alcohol 20 g
triethanolamine 1 g
water 19 g
TOTAL 50 g
The compositions (A) and (B) were separately
wet-ground in sand grinding mills to form aqueous suspensions.
Using these aqueous suspensions, a 20~ aqueous coating
formulation having the following composition was prepared.
Weight ratio
(solid matter)
2,5-dibenzoyl-1,4-benzoquinoneS
Luke Crystal Violet 2
calcium carbonate 53
Starkey acid aside 10
polyvinyl alcohol 20
The coating formulation was then applied by a Meyer bar
coaler onto a base paper web of 70 g/m2 to give the dry coat
weight of 6 g/m2, followed by its drying to obtain a heat-
sensitive recording paper. The heat-sensitive recording
paper was caused to produce its color by using a commercial
thermal printer, thereby obtaining prints of deep bluish
So
purple. A plasticizer (dioctylphthalate) was dropped on
the thus-printed portions. The prints deadweight show any
tendency of fading out and non-printed portions were not
observed to develop any color. The printed portions did
not tend to disappear or become thinner during its storage.
The heat-sensitive recording paper was thus excellent in
overall storage stability.
Example 2:
A heat-sensitive recording paper was obtained in
the same manner as in Example 1 except that wet-ground fine
N-phenyl-p-toluenesulfonamide particles my 96 - 98C) was here
in place of Starkey acid aside in the same amount. The heat-
sensitive recording paper of the present Example was printed
using a G-II model heat-sensitive facsimile machine ("OKIFAX*
5800" manufactured by Ok Electric Industry Co., Ltd.).
Deep bluish purple prints were obtained. The thus-produced
color prints were extremely stable as in Example 1.
Examples 3 - 7:
Aqueous suspensions having the following composition
were respectively prepared using as their chromoyenic reactants
4,4'-bis(dimethylamino)-3"-cyclohexyl-4"-methoxytrriphenyl-
methane, 4,4'-bis(dimethylaminophenyl)-4"-methoxynaphthyl
methane 4,4'-bismorpholino-3'-tert-butyl-4"-methoxytri-
phenylmethane, bis(4-dimethylaminophenyl)-~-styrylmethane
and 4,4'-dimethoxy-4"-dimethylaminotriphenylmethane and process-
in them in attritors.
* Trademark
Jo
- 34 -
(A) chromogenic reactant 10 g
10~ aqueous solution of 20 g
hydroxyethylcellulose
aqlleous solution of stroll- 1 g
trimethylammonium chloride
water 19 g
TOTAL 50 g
Using each of the above-obtained aqueous
suspension, the same aqueous suspension of the color-developing
agent as prepared in Example i and an aqueous suspension
of o-phenoxycarbonylphenyl(m.p. I - 85C)(C) prepared on
the side, a 20~ aqueous coating formulation having the following
composition was prepared.
Weight ratio
(solid matter)
2,5-dibenzoyl-1,4~benzoquinone 7
chromogenic reactant 2
talc 30
calcium carbonate 20
zinc Stewart 5
color production sensitivity
regulator
hydroxyethylcellulose 20
The above coating formulation was then applied to a base
paper web of 50 g/m2 to give a coat weight of 6 g/m2, thereby
obtaining a heat-sensitive recording paper.
Example 8:
The procedures of Example 3 were followed to give
-
- 35 -
a heat-sensitive recording paper having the following
composition-
color-developing agent [dupe- 5
methylbenzoyl)-1,4-benzoquinone]
chromogenic reactant [3,3'-dimethyl- 3
4,4'-bis(methylamino)-4"-dime~hyl-
aminotriphenylmethane]
calcined kaolin 30
precipitated calcium carbonate 22
zinc Stewart 5
color production sensitivity 10
regulator (resorcine bonniest)
hydroxyethylcellulose 25
TOTAL 100
The heat-sensitive recording paper of the present
Example gave deep bluish purple prints when printed by a
commercial thermal printer.
Example 9:
A heat-sensitive recording paper was obtained yin
the same manner as in Example 1 except that the color-
developing agent and chromogenic reactant were changed to
the following ones:
color-developing agent: 2,5-di-i-butoxycarbonyl-
3,6-di(p-tolylsulfonyl)-
1,4-benzoquinone
chromogenic reactant: bis(4-methylamino-3-methyl-
phenyl)-(4'-methoxystyryl)-
methane (30 wt.%); Bessel-
ethyl-2-methyl-indol-3-yl)-
4'-dimethylaminophenylmethane
(20 wt.%); and bis(l-ethyl-
2-methyl-indol-3-yl)-4'-
ethoxyphenylmethane (White.%).
Vised as a mixture.
I.
s
- 36 -
The heat-sensitive recording paper of the present
Example produced a deep black color when kept for 5 seconds
in contact with a hot plate of 200C. The thus-produced color
mark did not show at all any tendency to fade out even when
brought into contact with plasticizers, oil, fat and the like.
Examples 10 - 13:
Heat-sensitive recording papers were obtained,
following the procedures of Example 2 except that the following
color-developing agents were used respectively. All the heat-
sensitive recording papers were printed by a G-II model facsimile
machine. They all gave deep bluish purple prints. Densities
of colors which had respectively been obtained by keeping
the above heat-sensitive recording papers in contact for
5 seconds with hot plates of 200C were also measured. Results
are summarized in Table 1.
Table 1
Example Color-developing agent produced color
. . . .... __
2,3,5,6-tetraethoxycarbonyl- 1.42
1,4-benzoquinone
_ . ___
11 2,5-di-n-butylsulfonyl-3,6- OWE
diethylcarbonyl-1,4-
benzoquinone
__ _ . . _ _ ._ _
12 2,5-diphenylsulfonyl-3,6-di- 1.38
i-butoxycarbonyl-1,4-
benzoquinone
__
13 2,5-dibromo-3,6-di-cyclohexyl- 1.39
oxycarbonyl-1,4-benzoquinone _
r
37
All the heat-sensitive recording papers exhibited
good stability with respect to their respective color images.
Comparative Example I
Bisphenol A and Crystal Violet Lactose were respectively
wet-ground into fine particles and then framed into aqueous
suspensions in the same manner as in Example 1.
Using the above aqueous suspensions, an aqueous
coating formulation having the following composition was
prepared.
Weight parts
(solid matter)
bisphenol A 20
Crystal Violet Lactose 8
Starkey acid aside 20
calcium carbonate 32
polyvinyl alcohol 20
The above aqueous coating formulation was applied
on a base paper web of 70 g/m to give the dry coat weight
ox 7 g/m2, followed by its drying to obtain a heat-sensitive
recording paper. The heat-sensitive recording paper produced
a deep bluish purple color when printed by a thermal printer.
Printed portions were brought into contact with ductile
phthalate. The color image disappeared immediately and become
unlegible.
Comparative Example 2:
Bouncily p-oxybenzoate and 3-diethylamino-6-methyl-
7-anilinofluoran were respectively wet-ground into fine
~.2~8~
3 8
particles and then converted into aqueous suspensions in
the same manner as in Example 1.
Using these aqueous suspensions, an aqueous coating
formulation having the following composition was prepared.
weight parts
(solid matter)
bouncily p-oxybenzoate 20
3-diethylamino-6-methyl-7- 9
anilinofluoran
zinc Stewart 10
talc 41
polyvinyl alcohol 20
The above aqueous coating formulation was applied
on a base paper web of 70 g/m2 to give the coat weight of
7 g/m2. The heat-sensitive recording paper of the present
Comparative Example produced a deep black color when printed
by a G-II model facsimile machine. When cotton seed oil was
brought into contact with the thus-printed portions, the black
disappeared immediately and became unlegible. The thus-
printed paper was stored at a dark place in a room. It showed
the tendency of natural fading. The color images or marks,
produced on the heat-sensitive recording paper, were generally
poor in stability.
Referential Example l:
Each of the heat-sensitive recording papers ox
Examples l and 2 was caused to produce its color by keeping
it in contact with a metal block having the temperature gradient
39
of 60C - 200C, for 5 seconds and under the pressure of
10 g/cm2, using Thermotest Rhodlaceta muddle 7401;
manufactured by SETARAM Corporation). Upon an elapsed
time of 10 minutes, the relationship between the color
densities and color production temperatures was studied using
a Macbeth densitometer (visible filter). A higher color
density indicates a deeper color. Results are summarized
in Hirable 2.
Table 2
__ _
Color production
temperature (C)60 70 80 85 90 95 100
Example 10.06 0~06 0.10 0.20 0.28 0.35 0.42
Example 2 ¦ 0.06 0.06 0.10¦ 0.21 0.40
Color production I 110 120 1 130 ¦ 140 150 ¦160
temperature ( C) I _ ! I
Example 1 ¦ 0.57 0.71 ¦ 0.86¦ 1.00 1.12 1.20
_ ' . .
sample 2 ! 1.20_ 1 31 1.35l 1.35 1.35 1.35
Referential Example 2:
Each of the heat-sensitive recording papers of
Examples 1 and 3 - 7 was kept for 5 seconds in contact with
a metal block having the surface temperature of 200C to
produce a color thereon. Furthermore, it was subjected to
POS(point of sales) bar code printing, using a desk-top bar
code label printer (Model BP-70; manufactured by Turk
Seiko OK The heat-sensitive recording papers produced
marks of the corresponding colors respectively. Anti-ester
_ . _
~1:2~
;'
- 40 -
property and storage stability tests were carried out on
the marks p r so, which were produced by the metal blocks,
and the recording papers bearing the marks respectively.
Test results are shown in Table 3:
Table 3
.
. Ant Lester Storage
En. Color aenslty(hue) property* stability*
1 blush purple) 1.42 1.41
. . .____ _ ..
3 dupe green) 1.38 1.38
4 Derek blue) 1.25 1.21
_ . . .. . ...
1.35tdeep green) 1.36 1.35
_ . _~_ ___ .
6 Derek green) 1.34 1.33
7 Rudy) 1.36 1.38
Note: * Each of the marked papers was brought into contiguous
relation with a paper file made of soft polyvinyl
chloride ("Right Clear Pocket") and then kept for
24 hours and at 60C in a constant-temperature
chamber while maintaining the load of 1 kg per
0.01 my. Thus, the marked paper was kept in contact
with a plasticizer (ester) present in the polyvinyl
chloride. The extent of fading of the mark was
measured.
** Storage stability test:
Each marked paper was stored at a dark place for
6 months to investigate any change in the density
of the produced color.
