Note: Descriptions are shown in the official language in which they were submitted.
~a~5~692 ~ ~
~ liS invention relates to photopolymerizable composi-tions
which are useful as coating and printing ink vehicles and more
particularly to pigrnented photopo:Lymerizable coatings and inks
which are stable to premature gelation.
Printing inks and coatings prepared using photopolymeriz-
able vehicles are known to the art which can be polymerized and
dried by exposure to ultraviolet radiation as example, U.S.
2,453,769, 2,453,770, 3,013,895, 3,051,591, 3,326,710, 3,511,710, ;
3,772,062 and 3,804,735.
These photopolymerizable inks and coatings are generally
pigmented ethylenically unsaturated polyester compositions. When
photoinitiators are incorporated in the composition, thin liquid ~ ;
films of the photopolymerizable composition can be cured to a
hard film within 1 second or less using medium pressure mercury
lamps.
The use of photopolymerizable inks and coatings eliminates
the use of volatile organic solvents and the high cost and time
of oven-baking which has heretofore been the conventional prac-
tice for drying and hardening inks and coatings.
In formulating inks ùsing photopolymerizable unsaturated ~ ,
polyester vehicles, it was found that for some unexplainable
reason, when the ester vehicles, which are normally stable to
gelation at room temperature were pigmented with colorants,
the ester vehicle self-polymerized within a short time to form
undesirable gels. The formation of gels in the ink or coating
formulation substantially destroys the commercial utility of
the formulation. Preventing the gelation of the pigmented
formulation or at least extending the time in which a pigmented
composition will gel is important in commercial
.
: :~
~ 5~D6~ ~
practice as several weeks storage is often required between
formulation of the ink or pigmented coating and actual use of the
formulation in printing and coating applicakions.
In accordance with the present invention there is provided
photopolymerizable compositions which exhibit impro~ed stability
to gel formation and which may be rapidly polymerized and hardened
by exposure to a source of ultraviolet radiation, the compositions
being comprised of an ethylenically unsaturated ester and a small
but effective amount of a stabilizing combination of a copper con-
taining compound and a thiocarbamate compound having the formula:
M ~ S - C - N f~CH2)Xl
1 ~,
. S n
wherein M is x~CH2) `2~N-, x(CH2 R ,N-C-S-, ~NH4 ) or a
metal cation having a valence of l to 3 and each of R, Rl, R2, and
R3 (same or different) are hydrogen, aryl, saturated and unsaturated
2~ alkyl groups having 1 to 20 carbon atoms, aralkyl or alkaryl groups
having 7 to 15 carbon atoms and amino, sulfo-and oxy-substituted
alkyl and aryl groups, n is an integer of 1 to 3 and x is
an integer from 0 to 1. Thus, the alkyl groups represented by
R, Rl, R2 and R3 may be straight chain aliphatic groups, branched
chained aliphatic groups and cyclic aliphatic groups or form
heterocyclic ring structures with the nitrogen atom present in the
thiocarbamate compound.
When the combination of a copper containing compound and
a thiocarbamate compound of the type disclosed is incorporated in
ethylenically unsaturated esters and especially pigmented esters,
-- 2
. . . . .
, . , . , . ~., , . - : .
)69~
in accordance with the practice of the present invention, the
period of time during which the photopolymerizable ester will
withstand gel ~ormation is extended to commercially acceptable
levels. As will hereina-fter be illustrated, when either member
of the stabilizing com~ination is omitted from the photopolymer-
able composition, no appreciable diminution in gel time is
obtained.
The term "ethylenically unsaturated ester compound" as
used herein means, monohydric alcohol esters of ~ ethylenically
unsaturated acids, polyesters obtained by the reaction of an
~ , ~ -ethylenically unsaturated mono- or dibasic acid with a
polyhydric alcohol having 2 to 6 hydroxyl groups or a polyepoxide
containing at least 2 reactive epoxy groups in the polyepoxide
molecule and mixtures thereof.
Included within the meaning of ~ ethylenically
unsaturated acid are unsaturated monocarboxylic acids-having from
,.
3 to 6 carbon atoms, e.g. acrylic acid, methacrylic acid, crotonic
acid and sorbic acid and unsaturated dicarboxylic acids having 4
to 10 carbon atoms, e.g. maleic acid, tetrahydrophthalic acid,
fumaric acid, glutaconic acid, itaconic acid and the like.
Illustrative of photopolymerizable ethylenically un-
saturated polyesters useful in the practice of the present
invention are acrylic acid and methacrylic acid esters of
aliphatic polyhydric alcohols such as, for example, the di- and
polyacrylates and the di-and polymethacrylates of ethylene glycol,
polyalkylene glycols such as diethylene glycol, triethylene
glycol, tetraethylene glycol, tetramethylene glycol, the
correspondlng ether glycols, triethylolethane, trimethylolpropane,
pentaerythritol, dipentaerythritol and polypentaerythritols.
Typical unsaturated polyesters include, but are not limited
to, trimethylolpropane triacrylate, trimethylolethane triacrylate,
triethylolpropane trimethacrylate, trimethylolethane trimetha-
., .
~S~f~9'~
acrylate, tetramethylene glycol dimethacrylate, ethylene ylycol
dimethacryLate, triethylene glycol dimethacrylate, tetraethylene
glycol diacrylate, tetraethylene glycol dimethacrylate, pentaery-
thritol diacrylate, pentaerythritol triacrylate, pentaerythritol
tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol
triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol
pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol
dimethacrylate, pentaerythritol trimethacrylate, and dipentaery-
thritol dimethacrylate.
A preferred class of ethylenically unsaturated polyester
compounds useful in the practice of the present invention are the
reaction products of a polyepoxide having at least two reactive
groups in the polyepoxide molecule and an ethylenically un- ~
saturated acid such as the ~ ethylenically unsaturated mono- ~;
; carboxylic acids having 3 to 6 carbon atoms and ~, ~-ethylenic~
ally unsaturated dibasic acids having 4 to 10 carbon atoms
previously discussed. These polyepoxide derived polyesters
are well known to the art, e.g. U.S. 3,637,618, U.S. 3,408,422,
U.S. 3,373,075, and Br. 1,241,851.
Typical examples of polyepoxide compounds useful in the
preparation of ethylenically unsaturated polyesters preferred in
` the practice of the present invention include epoxidized poly-
butadiene (Oxiron 2001*), epoxidized linseed oil (Epoxol 9-5*),
1,4-butylene diglycydyl ether (RD-2), vinylcyclohexene diepoxide
(Epoxide 206), resorcinol diglycidyl ether (Kopoxite 159*),
. .
Bisphenol A diglycidyl ether (DER-332), s-tetraphenylethane
tetra-glycidyl ~ther (Epon 1031*), novalac resin polyglycidyl
ether (DEN 438), dicyclopentadiene diepoxide (Epoxide 207) and
dipentene dioxide.
Polyesters especially preferred in the practice of the
present invention are polyesters prepared by reacting Bisphenol
A diglycidyl ether, i.e. the diglycidyl ether of 2,2-bis
trademark 4
:
~sa~
(4-hydroxyphenyl propane) with an ethylenically unsaturated mono-
carboxylic acid such as acrylic or methacrylic acid at a molar
ratio of about 1:2 to prepare the diacrylate reaction product or
with an ethylenically unsaturated dicarboxylic acid such as
itaconic acid at equal molar ratios.
The Bisphenol A diglycidyl ether diacrylate may be blended
with the ~isphenol A diglycidyl ether itaconate as well as other
ethylenically unsaturated compounds and especially acrylate ester
compounds to prepare photopolymerizable mixtures ha~ing the physical
properties suitable for printing inks and coatings.
Examples of thiocarbamate compounds useful i~ the practice
of the present invention include, tetramethylthiuram disul~ide,
- tetraethylthiuram disulfide, tetrapropylthiuram disulfide,
tetrabutylthiuram disulfide, tetradecylthiruam disul-~ide,
tetrahexadecylthiuram disulfide, tetracicosylthiuram disulfide,
l-methyl-l-propyl-6-butyl~6- methyl thiuram disulfide, l-propyl-l-
butyl-6-methyl-6-t-butyl thiuram disul~ide, dihexamethylene thiuram
disulfide, dipentamethylene thiuram disul~ide, piperdinium
pentamethylene dithiocarbamate, piperdinium dibutyl dithiocarbamate,
piperdinium dicyclohexyl dithiocarbamate, piperdinium di(3-
: oxycyclohexyl~ dithiocarbamate, metal thiocarbamates as for
example, nickel dipropyldithiocarbamate, nickel dibutyldithio-
carbamate, nickel didecyldithiocarbamate, zinc dimethyldithio-
carbamate, zinc dibutyldithiocarbamate 9 zinc dihexyldithiocarbamate,
- sodium dibutyl dithiocarbama*e, copper dimethyl dithiocarbamate,
copper dibutyldithiocarbamate, copper diethyldithiocarbamate,
copper diamyldithiocarbamate, copper dioctadecyldithiocarbamate,
copper diphenyldithiocarbamate, copper dibenzyldithiocarbamate,
copper di(orthotolylaminoethyl) dithiocarbamate, copper
dicyclohexyldithiocar~amate, ammonium dipropyldithiocarbamate,
potassium dihexyldithiocarbamate, calcium dihexyldithiocarbamate,
zirconium diethyldithiocarbamate, cobalt dibutyldithiocarbamate,
- 5 -
.
.. . . . .
.
~ ~5~ 2
antimony dibutyldithiocarbamate, bismuth dimethyldithiocarbamate,
lead dimethyldithiocarbamate, tin dibutyldithiocarbamate, copper
dicyclopentyldithiocarbamate, copper l-butyl-l-cyclohexyl-7-butyl-7-
cyclohexyl ditlliocarbamate, copper di(3-oxacyclohexyl) dithio-
carbamate, copp~r di~4-oxacyclohex~l) dithiocarbamate, copper
di(3-thiocyclohexyl) dithiocarbamai:e, copper di(4-azacyclohexyl)
dithiocarbamate, copper l-butyl-l- (3-oxacyclohexyl)-7-butyl-i-
(3-oxacyclohexyl) dithiocarbamate, copper di(4-pyridyl) dithio-
carbamate, copper di (4-n,n-dimethyl anilino) dithiocarbamate,
copper di(4-anisyl) dithiocarbamate, copper di(4-thioanisyl)
dithiocarbamate, and copper di~3-furanyl) dithiocarbamate.
The thiocarbamate compounds may be incorporated in the
photopolymerizable ester compositions at concentrations ranging
from 0.10 to about 1.0% by weight. Higher concentrations may be
used if necessary, but concentrations substantially in excess of
1.0% by weight have been found to have a significant retarding
effect on the speed at which the photopolymerizable composition
will be cured by ultraviolet radiation.
- Copper containing compounds useful in the practice of
the present invention include any copper containing compound which
- is compatible with the photopolymerizable ester composition.
Illustrative examples of copper containing compounds
useful in the practice of the present invention include the
inorganic acid cupric salts such as cupric chloride, cupric
nitrate, cupric phosphate, cupric sulfate, cupric chromate,
organic acid cupric salts as for example cupric napthenate,
salts having the formula Cu (OOCR)2 wherein R is a saturated or
unsaturated straight or branched chain aliphatic substituent
having about 2 to 20 carbon atoms such as cupric acetate, cupric
~i 30 propionate, cupric butyrate, cupric hexoate, cupric octoate, cupric
laurate, cupric palmitate, cupric stearate, and cupric oleate.
Cuprouc compounds such as inorganic acid cuprous salts and
.:.. . :, ,. :.
~ Sv 6~ ~
organic aci~ c-lprous salts such as cuprous chloride, cuprous
acetate and the like are also inclllded within the meaning of
copper containing compounds and are useful in the practice of the
present invention.
In ~he event that photopolymerizable compositions are
pigmented with copper containing pigments such as copper
phthalocyanine, the separate inclusion of a copper compound in the
photopolymerizable composition is not generally required. As will
hereînafter be illustrated, photopolymerizable compositions
pigmented with copper containing pigments are stabilized to gel
formation merely by the addition thereto of a non-copper containing
thiocarbamate compound. However, if these same non-copper thio-
carbamate compounds are incorporated in a photopolymerizable
composition in which copper ion is absent, effective gel stabiliz-
ation generally does not occur. When the photopolymerizable composi-
tion is pigmented with a colorant that does not contain copper cation,
the stabilizing combination is most conveniently incorporated in the
photopolymerizable composition by the singular addition of a copper
; salt of a thiocarbamate compound as for example copper di-
butyldithiocarbamate.
The copper cation is desirably present in the photo-
polymerizable composition in an amount about stoichiometrically
equal to the amount of thiocarbamate compound incorporated in the
photopolymerizable composition. For example, when cupric compounds
are incorporated :in the photopolymerizable composition, the molar
ratio of Cu~+ ion to thiocarbamate radical is generally about 1:2.
When cuprous compounds are incorporated in the photopolymerizable
; composition the molar ratio of Cu+ ion to thiocarbamate radical is
generally about 1:1. It has been determined that the molar ratio
of Cu++ ion to thiocarbamate radical may vary -from 1:2, if the
ratio is appreciably greater than 1:2, as for example, 1:1? an
appreciable diminution in stabilizing effectiveness is encountered.
-- 7
:. : . :, ' . , .
Generally a molar ratio of Cu~ ion to thiocarbamate radical of about
0.8:2 to 1.5:2 will give bene~icia:L results, and a molar ratio ~f
about 1:2 to 1.2:2 is preferred. The molar ratio o~ Cu~ ion to
thiocarbamate radical may vary from about 0.8:1 to 1.2:1.
When copper containing pigments are used as Q source of the
copper cation for the stabilizing c:ombination, the pigments
although they may be incorporated in photopolymerizable ester
; compositions at relatively high concentrations, e.g. 5 to 25% by
weight of the ester composition, are substantially insolwble in the
ester composition and do not furnish an excessive amount o~ copper
ion to the ester composition. It has been found in practice that
by dispersing copper containing pigments in ethylenically un-
saturated photopolymerizable ester compositions 9 a sufficient
amount of copper ion is made available to the composition by the
pigment to form an effective stabilizer combination when used
cojointly with 0.1 to 1.0% by weight of a non-copper containing
thiocarbamate compound.
Illustrative examples of materials useful as pigments for
photopolymerizable ester based printing inks include copper
phthalocyanine blue (Pigment Blue 15), copper polychlorophthalo-
cyanine green, copper bromochlorophthalocyanine, carbon black,
Chrome Yellow #40-4500 (American Cyanamid), Naphthanil Red Dark
#RT-539-D (Du Pont) 9 Valencia Moly Orange #YE-421-D (Du Pont),
Watchung Rubine #RT-709-D (Du Pont), Sahara Yellow #X-2864
(Hercules), Bon Maroon Light #RT-533-D (Du Pont), Phthalocyanine
Blue #55-3295 ~American Cyanamid), Duplex Barium ~ithol #20-4480
(American Cyanamide), Paliofast Blue (non-metallic) #7560 (BASF),
Rhodamine B #20-7470 (American Cyanamid), Monastral Red B #RT-790-D
(Du Pont) and Supercarbovar #SRS-652 (Cabot).
Photoinitiators may be incorporated in the ester compositions
` used as vehicles for photopoIymerizable printing inks and coatings
to accelerate the speed at ~hich the inks and coatings harden on
., .
,, , , ~, , , . ~ , .................... . .
.-, ... . ....... . . ..
.- . , , . : . , . , : , . ..
exposure to ultraviolet light. Illustrative examples of suitable
photoinitiators include benzophenone, Michler's ketone (4,4'-bis
dimethylamino benzophenone) and mixtures thereof. The photo-
initiators are incorporated in the photopolymerizable compositions
at a concentration of 0.1 to 5$ by weight.
In general, printing inks prepared using the pigmented
photopolymerizable compositions of the present invention are
prepared in the same manner as conventional printing inks.
Generally, the printing inks contain about 30 to about 95 percent
by weight of the photopolymeri7able composition and about 5 to about
70 percent by weight of the pigment.
- In printing metal surfaces with ultraviolet curable
printing inks, the ink is applied using a printing press
conventionally used ~or printing on metal substrates. Once
the metal substrate, generally in the form of a sheet is printed,
the substrate is positioned to pass under a source of ultraviolet
light to dry and harden the ink. In most instances, the ultra-
violet light source is maintained at about 0.5 to about 5 inches
from the printed substrate undergoing irradiation.
; 20 Rapid drying of the inks using the stabilized photoinitiatedcompositions of the present invention is effected within a second
of exposure to ultraviolet light emitted from an artificial source
havlng a wave length in the range between 4000A and 1800A.
In the printing of metal coil stock for beverage container
manufacture where extremely high speed drying o-f the ink ~i.e.
within one second) is required, mercury vapor discharge lamps,
` especially of the medium pressure type are used as a source o
ultraviolet radiation. The output of commercially available medium
pressure mercury vapor lamps varies between 100 to 200 watts per
linear inch of lamp surface.
The present invention is illustrated by the Examples which
follow:
!:
- 9 _
: `
.... .
: ': ; .
For purposes of comparison, in a separate series of tests
run in accordance with the procedure of Exanlple 11 a number of
known stabilizer compounds as well as compounds closely related
to the compounds used in the present invention, but outside the
scope of the invention, were incorporated in the pigmented ink
vehicle and these comparison ink compositions were also tested for
gel stability. The results of these comparative tests, designated by
the symbol "C", are aIso summarized in Tables I and II. Also tests
in which no stabilizer compounds were incorporated in the pigmented
ink vehicle were also run and are also designated by the symbol "C"
in the Tables.
.. ~ . .
~ :.
1~5~69~
T~sLE I
Concen- Gellakion Time
Test tration ~Minutes)
No. Stabilizer Wt. % 40 80100 120 160
... . . . ... . _ . _ _ . . _
1 Zinc dibutyldithiocarbamate 0.25 Gel
2 Zinc dibutyldithiocarbamate 1.0 Gel
3 Nickel dibutyldithiocarbamate 0.5 Gel
4 Nickel dibutyldithiocarbamate 1.0 Gel
5 Tetraethylthiuram disulfide 0.2S Gel
6 Tetraethylthiuram disulfide 1.0 Gel
7 Sodium N,N-diethyldithiocarbamate 1.0 Gel
8 Piperidinium pentamethylene 1.0 Gel
dithiocarbamate
9 l-Pyrrolidenecarbodithioc acid 0.25 Gel
ammonium salt
10 l-Pyrrolidenecarbodithioc acid 1.0 Gel
-~ ammonium salt :
- Cl ~one 0 Gel
C2 p-Methoxyphenol 1.0 Gel
C3 p-Methoxyphenol 2.0 Gel
C4 2,6-di-tert,-butyl-4-methylphenol 1.0 Gel ~ -
C5 2,6-di-tert,-butyl-4-methylphenol 2.0 Gel
C6 1,1,3,3-tetraethyl-2-thiourea 1.0 Gel
~: C7 N,N-Dimethylthioformamide 1.0 Gel
C8 Zinc isopropyl xanthate 1.0 Gel ~ :~
,~
., .
`'''' ' - '
., .
., .
- 12 -
.
;,,~. . . . ,.. , , .. ~ .. . :.,
-- latSV6~
TABL~ II
-
Concen-Gellation Time
Test tratlon (Minutes)
No. Stabilizer Wt. % Pigment 20 ~0 60
11 Zinc dibutyl dithiocarbamate1.0 CPG Gel
Cg 2,6-di-t-butyl-4-methylphenol 1.0 CPG Gel
C10 2,6-di-t-butyl-4-methylphenol 2.0 CPG Gel
Cll None 0 CPG Gel
C12 Zinc dibutyldithiocarbamate0.25 NPB Gel
C13 ~ickel dibutyldithiocarbamate 0.25 NPB Gel
14 0 NPB Gel
... ..
The data in Tables I and II indicate that copper
phthalocyanine pigmented photopolymeriza~le compositions stabilized
with a thiocarbamate compound in accordance with the practice of the
present invention exhibit superior storage stability when compared
to copper phthalocyanine pigmented photopolymerizable compositions
stabilizéd with compounds outside the scope of the invention as well
as photopolymerizable compositions pigmented ~ith non-copper con-
taining pigments and thiocarbamate compounds.
EXAMPLE II
~ .
A zinc dibutyldithiocarbamate stabilized, copper
phthalocyanine blue pigmented photopolymerizable ~omposition
composed of the composition used in Test number 1 of Table 1 was
applied to steel plate of the type used in the manufacture of steel
beverage containers using a number 10 draw bar which evenly dis-
tributed the composition as a thin film on the plate.
After application o~ the stabilized pigmented photo-
polymerizable composition, the coated plate was placed under a
medium pressure mercury lamp at a distance of about 1.0 inch from
the lamp sur~ace.
'
- 13 -
,.. . . .
::, . . . . . .
:: -.- - . . . .
'` t ' : ' .
The radiation emitted by the lamp was approximately
200 watts/in. of lamp surface. The coated plate when exposed to
the ultraviolet radiation dried in 0.6 seconds.
EXAMPLE III ?
A series of accelerated ink vehicle storags stability
tests were conducted following the procedure of Example I with the
exception that 17.565 grams of ink vehicle were used, having
incorporated therein 12 percent by weight, based in the weight o~
the vehicle, of a variety of different pigments which did not con-
10 tain copper ion and 0.20 and 0.50 percent by weight of copper
dibutyldithiocarbamate ~CDBDTC). Ihe results of these accelerated
storage stability tests are recorded in Table III below.
For purposes of comparison, in a separate series of
~- accelerated storage stability test, 0.25~ zinc dibutyldithiocarbamate
~ZDBDTC) and 0.50% by weight copper napthenate (CNAP) were
separately incorporated in the differently pigmented vehicles.
The results of these comparative accelerated storage stability
tests are also recorded in Table III below.
'.~ '
. ' ', , ~
, ' .
`
.. ,
~'~ .
'
: .
. .
- 14 -
,.. . . . .. .... .. .. . . . . .
. :. . ., , . : ., , .. . . ~ , ..... . . .
;C~2
TABLE III_
G.LLLATION TIME (minutes)
Pigmented Pigmented Pigmented Pigmented
Vehicle Vehicle Vehicle Vehicle
Pigment Incorporated + ~ ~
In CDBDTC ZDBDTC CNAP No Stabilizer
Vehicle 0.2% 0.5~0~2'i% 0.50% Added
_.
None 150* 220 60 20 80
Duplex Barium Lithol 120 370 40 30 40
Rhodamine B 180 270 20 20 40
Naphthanil Red Dark 160 310 40 20 40
Watchung Red 160 410 40 10 40
Bon Maroon Light 120 270 80 20 40
Sahara Yellow 210 390 60 10 60
.
Paliofast Blue 120 290 60 20 80
; Monastral Red B 180 430 60 20 60
: Chrome Yellow 120 200 20 10 20
Moly Orange 210 430 20 10 40
Moly Orange - - 20~*
:
. Moly Orange - - 20***
.- ' ~.
* 0.05% by weight CDBDTC used.
** 1% by weight ferric dibutyldithiocarbamate substituted for
0.25% by weight ZDBDTC.
*** 1% by weight silver dibutyldithiocarbamate substituted for
0.25~ by weight ZDBDTC.
The data in Table III lndicates that photopolymerizable
compositions pigmented with pigments which do not contain copper ``
must have a combination of a copper containlng compound and a
thiocarbamate compound incorporated therein to stabilize the
pigmented composition to gel formation.
- 15 -
~ ~ S0 ~3
EXAMPLE IV
A series of accelerated ink vehicle storage stability tests
l~ere conducted following ~he procedure of Example III using un-
pigmented vehicle and moly orange pigmented vehicle. Zinc di-
butylditlliocarbamate at a concentration of 0.25% by weight ~equal
to 3.16 x 10-4 moles dibutyldithiocarbamate) and varying amounts
of C~C12 were incorporated in the vehicles. The results of these
accelerated storage stability tests are recorded in Table IV below.
TABLE IV
GELLATION TIME (minutes)
Concentration
Moles
Test CuC12 Cu'~ Unpigmented Pigmented
No. (Wt.~) x10-4 Vehicle Vehicle
1 0 0 80 60
2 0.05 0.88 160 160 `
` 3 0.10 1075 180 160
4 0.20 3.52 60 40
0.30 5.28 20 40
6 0.40 7.04 20 40 ` ~ -
7 0.50 8.80 20 40
'
The results of the accelerated ink vehicle storage stability
tests recorded in Table IV indicate that combinations of dibutyldi-
thiocarbamate compounds and copper containing compounds are
; effective stabilizer combinations for ethylenically unsaturated
photopolymerizable compositions (Tests nos. 2-3). However when the
molar amounts of Cu+~ and dibutyldithiocarbamate radical are
substantially greater than 1:2, e.g. 1:1 or greater as in Tests
numbers 4-7, the stabilizing effect of the combination is sub-
stantially reduced to an ineffective state.
. .
',
- 16 -
.~ .
.
:: ~ . ..
. . . - .
:., . : .
~ , .. ~ . . . . '
E_~MPLE V 1 05~D~92
In a series of accelerated lnk vehicle storage stability
tests the procedure o-f Example III was repeated with the exception
that a variety o-f different pigments were incorporated in the
vehicle along with a stabilizing combination of 0.25% by weight
zinc dibutyldithiocarbamate (ZDBDTC) and 0.5% by weight copper
napthenate (CNAP). The results of these accelerated gel stability
tests are recorded in Table V below.
For purposes of comparison, in a separate series of
accelerated storage stability tests 0.25% by weight ZDBD~C and
0.50% by weight CNAP were separately incorporated in the different
pigmented vehicles. The results of these comparative accelerated
gel stability tests are also recorded in Table V below.
TABLE V
TIME FOR GELLATION ~Minutes)
Vehicle
ZDBDTC Vehicle Vehicle
+ + ~ .
20 Pigment CNAP ZDBDTC CNAP Vehicle ;~ ~
___ _ :
None 220 60 20 80
DuPlex Barium 140 40 20 43
Lithol
Rhodamine B 160 20 20 40
Naphanil Red 240 40 40 40
Dark
Watching Rubine 240 40 20 40
Bon Maroon Light 140 80 40 40
Monastral Red B 240 60 20 60
Chrome Yellow 80 20 20 40
Moly Orange 80 20 20 40
Sahara Yellow 240 60 20 60
Cyano Blue 120 120 20 20
(contains Cu)
Cyano Blue 220 60 20 80
: . ~
~5~V~9z
EXAMPLE VI
.
In a series of acceleratecl ink vehicle storage stability
tests the procedure of Example III was repeated using unpigmented
vehicle and moly orange pigmented vehicle. A stabilizing
combination of 0.25% by weight zinc dibutyldithiocarbamate
(ZDBDTC) and 0.05% by weight CuCl was separately incorporated in
the vehicles. The results of these accelerated gel stability
tests are recorded in Table VI below.
F'or purposes of comparison, in a separate series of
- l0 accelerated storage stability tests, 0.05% by weight CuCl has
separately incorporated in the vehicles. The results of these
- comparati~e accelerated gel stability tests are also recorded
in Table VI below. `!
TABLE VI ~ -
TIME FOR GELLATION (Minutes)
Vehicle
+
ZDBDTC Vehicle
,,, +
20 Pigment CuCl CuCl Vehicle
,: - - - ~ .
None 200 6Q 60
Mo1y Orange 140 20 -
'''- ,': ,'
,- ' '
. .
- 18 -
'
: ':: . ' `: `
