Note: Descriptions are shown in the official language in which they were submitted.
- t 2i 68~95
Description
RECORDING SHEETS FOR INK JET PRINTING
Field of Invention
This invention relates to recording sheets
suitable for use in an ink jet recording process,
particularly it relates to ink receiving sheets where
images recorded thereon can be observed by both
reflected and transmitted light. Ink jet receiving
materials used at the present time have a particular
need for improvement in physical and handling
properties, particularly in waterfastness and light
stability as well as for improved image quality. A
preferred embodiment of this invention is therefore
directed towards ink jet recording materials with
improved handling and performance characteristics, in
particular ink receiving materials where the images
recorded thereon are resistant to rubbing on the
surface or to damage by other physical means, remain
intact in contact to water and do not fade when exposed
to light even under adverse conditions. The present
invention provides a solution towards these problems.
Ink jet printing systems generally are of two
types: continuous stream and drop-on-demand. In
continuous stream ink jet systems, ink is emitted in a
continuous stream under pressure through an orifice or
nozzle. The stream is perturbed, causing it to break
up into droplets at a fixed distance from the orifice.
At the break-up point, the droplets are charged in
accordance with digital data signals and passed through
an electric static field which adjusts the trajectory
of each droplet in order to direct it to a gutter for
recirculation or a specific location on a recording
` -
21 6~q95
medium. In drop-on-demand systems, a droplet is
expelled from an orifice to a position on a recording
medium in accordance with digital data signals. A
droplet is not formed or expelled unless it is to be
placed on the recording medium.
Although the main effort in this invention is
directed towards the more demanding continuous stream
system it is not meant to be restricted to either of
the two methods.
Backqround Art
The following requirements describe some of the
major features of a recording material used in ink jet
printing:
1. Sufficient ink absorbing capacity and ink
receptivity of the receiving layer to prevent the ink
from streaking and from running down during printing,
even under conditions where several droplets are
deposited in a rapid sequence onto the same spot.
2. Fast drying of the layer surface after
printing of the image leading to prints free from
tackiness.
3. Excellent colour rendition, no change of the
hue of the picture with time.
4. Surface with high gloss.
5. In the case of transparencies, clear,
transparent, scatter free receiving layers.
6. Resistance of the image surface of the image
to rubbing.
7. Excellent waterfastness of the produced
images.
8. Excellent light fastness of the printed
images.
9. Excellent archival stability.
10. Excellent physical and handling properties.
21 68995
The particular problem of waterfastness has in the
past been addressed by a wide variety of techniques.
Thus solutions to the problem have been proposed for by
specific formulations of the inks-or alternatively in
many cases by specific modifications of the receiving
layers. The two approaches have in many cases been
combined.
One attempt to improve waterfastness has been the
use of reactive dyes. So for instance in US 4 443 223
(Kissling et al.), US 5 098 475 (Winnik et al.), US 5
074 914 (Shirotz et al.), US 5 230 733 (Pawlowski et
al.), JSDC (1993) 109, 147 (S.O. Aston et al.) and
references cited therein. Although some improvement
has been achieved by this technique no satisfactory
results can in general be obtained due to the fact that
the conditions which are possible in practice in a
printing environment are less than optimal and do in
general not suffice to achieve reaction of these dyes
with given binders. Inks based on colloidal dye
dispersions and polymers in inks have been proposed so
for in instance in US 5,100,471 (Wink et al.),
5,017,644 (Fuller et al.), 4,990,186 (Jones et al.), US
4,597,794 (Kasha et al.), US 4,210,566 (Murrey), US
4,136,076 (Dennison et al.), US 5,224,987 (Matrick et
al.), US 5,180,425 (Matrick et al.) and US 4,246,154
(Yao et al.). Inks based on colloidal dyes as well as
on hot melt inks, although yielding images with good
waterfastness and good light stability, do in many
cases lead to images which are not transparent and
therefore less suited to be used for projections.
Often involved modifications of the inks have the
tendency to give inks liable to show precipitates upon
prolonged storage. Such precipitates subsequently tend
to clog the nozzles of ink jet printer.
The major attempt to achieve waterfastness in
21 6~9q5
--4--
receiving layers has been via the use of polymers,
particular cationic polymers in conjunction with inks
containing acidic dyes.
US 4,877,680 describes cationic polymers together
with neutral binders. Cationically modified polyvinyl
alcohol has been described in US 4,783,376. US
4,575,465 claims quaternised polyvinyl pyridine to
achieve waterfastness. US 4,554,181 describes the use
of a combination of cationic polymers and polyvalent
metal salts since only such combinations and not the
single elements tend to provide the sought for
properties.
Although good waterfastness can in general be
obtained with a wide variety of cationic polymers they
tend to show a severe drawback in that they impair the
light fastness of the printed images.
The introduction of inorganic pigments, fillers,
minerals, metal salts and metal oxides have been
proposed. US 4,116,910 (Rudolphy et al.) propose the
use of derivatives of metals of Group II of the
periodic table together with natural resin. JP 6025
7285 (Nakadsugawa et al.) claims an improvement of
light stability by addition of transition metal oxides.
Waterfastness can preferentially be achieved by
addition of metal oxides together with cationic
pigments or polymers to the receiving layers. US
5,104,730 (Misuda et al.) and US 4,819,166 (Misuda et
al.) describe porous recording sheets where the porous
layer is mainly made of pseudo boehmite, a colloidal
aluminium oxide hydroxide. Although in general
satisfactory waterfastness can be achieved the layers
obtained by this method are slightly opaque and show
severe tendency to become brittle with time and on
exposure to light. All the above mentioned solutions
fulfil only partly the requirements of image receiving
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layers for modern ink jet printing. In many cases
these solutions lead moreover only to material suitable
for quite restricted applications. Improvements
incorporated into ink receiving layers, widely
applicable to modern ink jet printing technology, are
therefore the scope of this invention.
Disclosure of the Invention
Accordingly, an object of the present invention is
to provide image receiving media for use in ink jet
recording which are particularly excellent in water
resistance.
Another object of the invention is to provide
recording media which achieve waterfastness without
affecting the stability of the obtained images against
the detrimental effect of light.
A further objective is to obtain recording layers
with excellent surface properties showing high
resistance to physical damage like for instance
scratching, resistance to cracking and moist rubbing on
the surface.
Still another objective of the present invention
is to provide receiving layers with excellent ink
receiving properties.
Another objective of the invention is to obtain
recording media which satisfy in sharpness and surface
lustre of the recorded image and are free from
stickiness of the surface even under highly humid
conditions.
A further objective is to provide recording media
suitable to be used on ink jet printers of the
continuous stream type.
A further object is to provide media which allow
the possibility to print images intended to match those
on silver halide photographic material.
21 6~995
It is furthermore the objective of this invention
to provide clear, scattering free recorded images on
transparent base material intended to be projected.
An additional objective of this invention is to
obtain a recording medium suitable for office desk top
publishing of color graphics which has improved
lightfastness.
This invention proposes to achieve above
objectives by providing a recording material wherein
said receiving material consists of a support, opaque
or transparent, onto which has been coated a receiving
layer or layers comprising a binder or a mixture of
different binders, fillers ! natural or synthetic
polymers and wherein are imbedded or coated at least
one trivalent salt of the metals of Group IIIb of the
periodic table of the elements or complexes which
comprise trivalent ions of the metals of Group IIIb of
the periodic table of the elements.
To these layers can be added a wide variety of
additional elements to further improve the pictorial
or/and physical properties of the images obtained when
printed on an ink jet printer.
Best Mode of Carryinq Out the Invention
The present invention will now be described in
detail. The ink receiving sheets according to this
invention specifically relate to layers wherein are
imbedded or coated trivalent metal salts taken from the
Group IIIb or complexes containing trivalent ions of
these metals of the periodic table of elements, in
particular salts or ions of the metals of atomic number
21, 39, 57 through to 60 and atomic of numbers 63 to
70. Preferred are the salts or complexes of Y, La, Ce,
Pr, Nd and Yb. These salts or complexes may be in form
of water soluble or in form of water insoluble
2l 68~5
compounds.
The water soluble metal salts of this invention
can be present as halides, salts of most oxo acids,
sulphates, nitrates, perchlorates, bromates but also as
carbonates, phosphates or hydroxides. Also salts of
organic acids can be used.
Often the compounds are present as dissociated
hydrated species or aqueous complexes and are in
general used as such. The salts of the invention can
also be used as mixtures made up of single species.
There is no limitation as far as the ratios of the
mixtures are concerned.
The compounds of the invention can be used in form
of their double salts containing besides the claimed
Group IIIb elements Ca, Mg, Ba, Na, K or the like.
Double salts can be in form of, for instance,
sulphates, nitrates, phosphates or in other forms known
to those skilled in the art. The use of metal
complexes is equally possible under the terms of the
invention. Examples of this type are those with
chelating ligands like for instance diketones or
organic phosphates. Some of the salts of the claimed
compounds when readily water-soluble are introduced
into the receiving sheets as aqueous solutions. In
many instances the claimed metal derivatives are only
sparingly soluble in water and have to be applied in
colloidal form or in form of fine dispersions.
The salts or complexes of Group IIIb elements
coated directly on the substrate or incorporated into
the ink receiving layers of the proposed recording
material are added in an amount of 0.05 - 3.0g/m2,
preferentially in amount of 0.1 to O.9g/m2. In the
embodiment where the salts or complexes of Group IIIb
elements are coated directly on the substrate, they are
preferably applied as 3-5% aqueous solutions on the
2l 68q95
surface of the substrate. After evaporation of the
aqueous solution the salts or complexes essentially are
absorbed into the substrate surface. In this
embodiment a preferred substrate includes a base paper
sheet coated with a silica and polyvinyl alcohol matrix
prior to application of the coating solution.
The use of the salts or complexes of the group
IIIb perform most efficiently when they are imbedded
into layers or coated onto substrates which have the
ability to rapidly absorb aqueous inks. The absorbing
power of the layer is to a great extent a function of
the materials used but likewise of the physical
properties of the layers and the substrate. The
compounds that make up the imbedding matrix include in
general water soluble film forming polymers.
These film forming water soluble polymers may
include, for example, natural polymers or modified
products thereof such as albumin, gelatine, casein,
starch, gum arabic, sodium alginate, hydroxyethyl
cellulose, carboxylmethyl cellulose, ~ - or
y-cyclodextrine and the like; polyvinyl alcohol;
complete or partial saponified, products of copolymers
of vinyl acetate and other monomers; homopolymers or
copolymers with other monomers of unsaturated
carboxylic acids such as (meth) acrylic acid, maleic
acid, crotonic acid and the like; homopolymers or
copolymers with other vinyl monomers of sulfonated
vinyl monomers such as vinylsulfonic acid, sulfonated
styrene and the like; homopolymers or copolymers with
other vinyl monomers of (meth)acrylamide; homopolymers
or copolymers with other monomers of ethylene oxide;
polyurethanes, polyamides having such groups as
mentioned above; polyethyleneimine, polyacrylamides,
water soluble nylon type polymers,
polyvinylpyrrolidone, polyester; and so on. All these
~l 6~995
can also be used in mixtures.
These polymers can be blended with non water
soluble natural or synthetic high molecular compounds.
Suitable synthetic polymer materials can be chosen
from among poly(vinyllactams, acrylamide`polymers,
polyvinyl alcohol and its derivatives,
polyvinylacetals, polymers of alkyl and sulfoalkyl
acrylates and methacrylates, hydrolyzed polyvinyl
acetates, polyamides, polyvinyl pyridines, acrylic acid
polymers, maleic anhydride copolymers, polyalkylene
oxides, methacrylamide copolymers, polyvinyl
oxazolidinones, maleic acid copolymers, vinylamine
copolymers, methacrylic acid copolymers,
acryloyloxyalkylsulfonic acid copolymers,
sulfoalkylacrylamide copolymers, polyalkyleneimine
copolymers, polyamines, N,N-diallylaminoalkyl
acrylates, vinyl imidazole copolymers, vinyl sulphide
copolymers, halogenated styrene polymers,
amineacrylamide polymers, polypeptides and the like.
Non-water soluble polymers can also be used in
some cases.
In the case where one of the water-soluble
polymers is gelatine the types of gelatine suitable for
use in the present invention include all kinds of
gelatine currently known, for instance acid pigskin or
limed bone gelatine, acid or base hydrolysed gelatines,
but also derivatised gelatines like for instance
phthalated, acetylated or carbamoylated, or gelatine
derivatives with trimellytic acid. The preferred
gelatine is a gelatine with an isoelectric point
between 7 and 9.5.
The polymers mentioned above having reactive
groups or groups having the possibility to react with
a crosslinking agent can be cross linked to form
35 essentially non water-soluble layers. Such
~l 6~?~995
--10--
crosslinking bonds may be either covalent or ionic.
Thus crosslinking allows for the modification of the
physical properties of the layers, like for instance in
water absorbency of the layer, but also in resistance
against physical damage.
Crosslinking agents suitable for this particular
use are selected depending on the water-soluble polymer
used. They may include for example chromium salts-
(such as chrome alum or chromium acetate), aldehydes
(such as formaldehyde, glyoxal or glutaraldehyde),
N-methylol compounds (such as dimethylolurea or
methylol-dimethylhydantoin), dioxane derivatives (such
as 2,3-dihydroxydioxane), activated vinyl compounds
(such as 1,3,5-triacrylolyl hexahydro-s-triazine or
bis(vinylsulfonyl)methyl ether), activated halogen
compounds (such as 2,4-dichloro-6-hydroxy-s- triazine),
amino or substituted-amino modified triazines,
epoxides, carbamoyl-pyridinium compounds or mixtures of
two or more of above mentioned crosslinking agents.
The layers and coatings can be modified by
addition of fillers. Possible fillers of the kind are
for instance kaolin, talcum, Ca- or Ba-carbonate,
silica, titanium oxide, chalk, bentonite, zeolite,
aluminium silicate, calcium silicate, silicium oxide,
colloidal silicium oxide and the like. Likewise the
possibility exists to use organic inert particles such
as polymer beads. This includes beads made from
polyacrylates, polystyrene or different copolymers of
acrylates and styrene. These fillers are selected
according to the intended use of the printed image.
Some of these compounds cannot be used if the printed
image is to be used as a transparency. Alternatively
they are of interest in cases where the printed image
is to be used as a reflected image. Often the
introduction of such filler causes a desired matte
689q5
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surface.
The image recording elements of this invention
comprise a support for the ink receiving layer. A wide
variety of such supports are known and commonly
employed in the art. They include, for example, those
supports used in the manufacture of photographic clear
films including cellulose esters such as cellulose
triacetate, cellulose acetate propionate or cellulose
acetate butyrate, polyesters such as poly(ethylene
terephthalate), polyamides, polycarbonates, polyimides,
polyolefins, poly(vinyl acetals), polyethers, polyvinyl
chloride and polysulfonamides. Polyester film
supports, and especially poly(ethylene terephthalate)
are preferred because of their excellent dimensional
stability characteristics.
Likewise the usual supports commonly used in
manufacturing of opaque photographic material can be
used according to the present invention. They include
baryta paper, polyethylene-coated paper, polypropylene
synthetic paper, voided polyester as for instance
manufactured by ICI under the trade name of MELINEX as
well as voided polypropylene polyester likewise
manufactured by the same company. Preferred are clear
polyester, acetate, voided polyester or resin coated
paper. When such support material, in particular
polyester, is used a subbing layer is advantageously
added first to improve the bonding of the ink receiving
layer to the support. Useful subbing compositions for
this purpose are well known in the photographic art and
include, for example, polymers of vinylidene chloride
such as vinylidene chloride/acrylonitrile/acrylic acid
terpolymers or vinylidene chloride/methyl
acrylate/itaconic acid terpolymers. Also usable are
plain paper, comprising a wide variety of sizings,
cast-coated papers and aluminium foils.
2l 6aqq5
In certain embodiments of the invention, a
preferred substrate includes a base paper sheet coated
with a silica and polyvinyl alcohol matrix. When such
support material is used an aqueous coating of metal
salts or complexes of Group IIIb elements may be coated
directly on the substrate surface. The inclusion of a
film forming polymer in this coating formulation is
optional when the described substrate or a similar one
is used. This embodiment provides a recording medium
suitable for office desk top publishing of color
graphics and has improved lightfastness properties.
The ink-receiving layers or coatings according to
this invention are in general coated from aqueous
solutions or dispersions containing binders, additives,
pigments and the like as well as the metal salts or
complexes of use in the present invention. It is in
many cases necessary to add surfactants to those
coating solutions or dispersions allowing for smooth
coating and evenness of the layers.
Examples of suitable surfactants are non-ionic
surface active agents such as saponin (steroids),
alkylene oxide derivatives (such as polyethylene
glycol, polyethylene glycol/polypropylene glycol
condensates, polyethylene glycol alkyl or alkylaryl
ethers, polyethylene glycol esters, polyethylene glycol
sorbitan esters, polyalkylene glycol alkylamine or
amides or silicone/polyethylene oxide adducts),
glycidol derivatives (such as alkenylsuccinic acid
polyglycerides or alkylphenol polyglycerides),
aliphatic esters of polyhydric alcohols, alkyl esters
of sucrose, urethanes or ethers; a sulfuric acid ester
group or a phosphoric acid ester group, such as
triterpenoid type saponin, alkylcarboxylates,
alkylsulfonates, alkylbenzenesulfonates, alkyl-
naphthalenesulfonates, alkyl sulfuric acid esters alkyl
~l 68~q~
-13-
phosphoric acid esters, N-acyl-N-alkyltaurines,
sulfosuccinates,sulfo-alkylpolyoxyethynenealkylphenyl
ethers or polyoxyethylene alkyl-phosphates and cationic
surface active agents such as alkylamine salts,
aliphatic or aromatic quaternary ammonium salts (such
as pyridinium or imidazolium salts) or phosphonium or
sulfonium salt containing an aliphatic or heteroxyclic
ring. Equally suitable are fluorinated or perfluorin-
ated derivatives of the above mentioned compounds.
Specific examples of these surface active agents
are those described in, e.g. U.S. Pat. Nos. 2,240,472,
1,831,766, 3,158,484, 3,210,191, 3,294,540 and
3,507,660, British Pat. Nos. 1,012,495, 1,022,878,
1,179,290 and 1,198,450, U.S. Pat. Nos. 2,739,891,
2,823,123, 3,068,101, 3,415,649, 3,666,478 and
3,756,828, British Pat. No. 1,397,218, U.S. Pat. No,
1,397,218, U.S. Pat. Nos. 3,133,816, 3,441,413,
3,475,174, 3,545,974, 3,726,683 and 3,843,368, Belgium
Pat. No. 731,126, British Pat. Nos. 1,138,514,
1,159,825 and 1,374,780, 2nd U.S. Pat. Nos. 2,271,623,
2,288,226, 2,944,900, 3,253,919, 3,671,247, 3,772,021,
3,589,906 and 3,754,924, all incorporated by reference.
Besides being necessary for coating purpose
surfactants may have an influence on the quality of the
generated images and may therefore be selected with
this specific goal in mind. There lS in general no
limitation to the use of the types of surfactants used
as long as they do not interfere with the metal salts
and complexes used in the present invention and later
with the printing inks used for the production of the
image .
Typically the receiving layers according to this
invention have a thickness in the range of 0.5 to 30
microns, preferably in the range of 2.0 to 15 microns
dry thickness.
~l 6~995
-14-
The coating solutions or coating dispersions can
be coated onto a support by any number of suitable
procedures. Usual coating methods include immersion or
dip coating, roll coating, air knife coating,
extrusion, doctor blade coating, cascade coating,
curtain coating, rod coating, rod and/or blade
metering, or by spraying. An ink receiving system can
be built up by several layers. These layers can be
coated one after the other or simultaneously. It is
likewise possible to coat a support on both sides with
ink receiving layers. Alternatively the backside may
be coated with auxiliary layers like for instance
anticurl layers or antistatic layers. The way however
by which the claimed receptive layers are produced is
1~ not to be considered limiting for the present
invention. In addition to the above mentioned elements
ink receiving layers as claimed in this invention can
contain additional additives aimed at improving
appearance as well as performance of the produced
imaging material. It can for instance be beneficial to
add brightening agents to the layers of receiving
sheets. There is in general no limitation as to the
kind of brighteners used. Suitable brightening agents
are for instance stilbenes, coumarines, triazines or
oxazoles or others known in the art.
Light stability can in general be improved further
by adding UV absorbers to the layers. Although UV
absorbers are in general added to the topmost layer of
the system there is no limitation as to where within
the ink receiving element such light absorbing
compounds are added. The amount of UV-absorber can
vary from 200-2000 mg/m2, preferably however from 400mg
to lOOOmg/m2. Suitable types of absorbers can be for
example benztriazoles, benzophenones, derivatives of
acrylonitrile, thiazolidone, oxazole and thiazole.
21 63995
--15--
It is further known that images can be protected
from degradation by the addition of light stabilizers
and antioxidants. Examples of such compounds are among
others sterically hindered phenols, sterically hindered
amines, chromanols and the like. Above mentioned
additives can, if water-soluble, be added as aqueous
solutions. In the case where these compounds are not
water soluble the above mentioned additives can be
incorporated in the ink receiving element by common
techniques known in the art. The compound is typically
dissolved in a solvent selected from organic solvents
compatible with water, such as alcohols, glycols,
ketones, esters, amides and the like. Alternatively
the compounds can be added to the layer as fine
dispersions, as oil emulsions, as cyclodextrine
inclusion complex or loaded as fine dispersions on to
latex particles. Ultrasound or milling can be used to
dissolve or disperse marginally soluble additives.
Inks for ink jet printing are well known. These
ink consist in essence of a liquid vehicle and
dissolved or suspended therein a dye or pigment. The
liquid vehicle of the inks employed for the printing
according to the present invention consist in general
of water or a mixture of water and a miscible organic
component such as ethylene glycol, and higher molecular
glycolds, glycerine, dipropylene glycol, polyethylene
glycol, amides, polyvinylpyrrolidone,
N-methylpyrrolidone, cyclohexylpyrrolidone, carboxylic
acids and esters, ethers, alcohols, organosulfoxides,
sulfolane, dimethylformamide, dimethylsulfoxyde,
cellosolve, polyurethanes, acrylates and the like.
The non water part of the printing ink generally
serves as humefactant, cosolvent, viscosity regulating
agent, ink penetration additive, levelling agent or
drying agents. The organic component has in most cases
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21 68995
-16-
a boiling point which is higher than that of water. In
addition aqueous inks may contain inorganic or organic
salts to impart electrical conductivity. Examples of
such salts include nitrates, chlorides, phosphates and
the like and salts of low molecular, water soluble
organic acids like acetates, oxalates and similar. The
dyes and pigments suitable for the preparation of inks
usable with the receiving sheets of this invention
cover practically all classes of known colouring
compounds. Dyes or pigments typically used for that
purpose are described in EP 0 559 324 (Isganitis et
al.).
other additives present in usable inks are for
instance surfactants, optical brighteners UV absorbers
or light stabilisers, biocides and polymeric additives.
This description of inks is for illustration only and
not to be considered as limiting the invention.
The following test procedures were used to
evaluate and compare the ink receiving sheets described
in the present invention, unless otherwise specified in
the examples.
Waterfastness
Test sheets prepared according to the described
examples were printed on an IRIS ink jet printer model
3024 with standard Iris writing fluids. lcm by lcm
uniform patches were printed in cyan, magenta, yellow
and black to a density of about 2. After printing and
drying under ambient conditions for 12 hrs the density
of the individual patches were measured with an X-rite
densitometer. The samples were then placed in
deionized water at 20C for one minute. After one
minute the samples were removed from the water, allowed
to drip dry and remeasured. The difference between the
densitometer readings was recorded as % loss of optical
density and termed waterfastness.
21 6~9q5
Light Stability
Printed sample sheets obtained according to the
same procedure as needed for the above described water
fastness test were measured on the X-rite densitometer
and exposed in an Atlas Weather-Ometer with a 2500
W-Xenon lamp under conditions analogue to those set for
in ISO norm 10 977. The samples were exposed until a
total illumination of 40 kJoule/cm2 was reached. The
results were reported as % loss of density as
determined by the difference of the readings before and
after exposure.
ExamPle 1
18g gelatine with an isoelectric point of over
seven (Stoess type 70810) were dissolved in 360ml
deionized water. To this solution were added 12g
hydroxyethyl cellulose. (Tylose H20, obtained from
Hoechst AG) and l.Og of a surfactant (Olin lOG,
obtained from Olin Corporation). This solution was
divided into twelve equal portions and to each portion
was added the amount of metal-nitrate x H20 indicated in
Table 1. This amount corresponds to 0.125 mMol
nitrate-salt/g total binder. A control sôlution
contained no salt. Immediately before coating 0.55g of
a 3~ solution of 2-(4-dimethyl-carbamoyl-pyridino)-
ethane-sulfonate was added to each portion. These
solutions were then coated onto a subbed polyester
support using a barcoater. The final dry thickness of
the layers were approximately 8~. After drying at room
temperature for 12 hours the prepared ink receiving
sheets were treated as described in the above testing
procedures. The obtained results are reported in Table
1.
- Zl 6~995
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TABLE 1
Metal Salt x 9/9 Binder Vaterfastness Loss of Density in
H2O % of iritial De~sity
C M Y K
La~NO~)~ 6H2O 0.054 11 <1 4 8 6
Eu(N3)3 6H2O 0.056 1 <1 4 9 9
rb(NO3)~ SH2O 0.056 1 <1 3 11 5
Ce(N03)3 6H20 0.054 1 <1 3 9 8
Nd(NO3)~ 6H20 0.055 1 <1 5 11 12
Y(NO3)3 SH20 0.046 1 <1 4 7 9
Mg(NO~)2 6H20 0.032* c2 19 17 36 27
Ba(~03)2 0.033~ c 2112 27 27
Ca(NO3)2 4H2O 0.030~ c 27 18 33 27
Zn(N~)2 6H2 0.037~ c 26 20 39 29
Al(NO~)~ 9H?O 0.047 c 45 11 13 29
None 0 c 3620 31 36
KEY: 1 Invention 2: Comparison
~ Coatings ~ith most of the comparative salts ~lere c~oudy and could not possibly
be used for transparent ink receiving materia~.
From the results in Table 1 can be seen that
excellent waterfastness can be achieved with recording
media according to the present invention while
appreciable dye bleeding occurred with salts according
to the:state of the art.
ExamPle 2
Ink receiving sheets were prepared in an analogous
way as described in Example 1. In two cases the metal
salts were replaced by cationic polymeric mordants
(U.S. 4,575,465) as indicated in Table 2.1 and 2.2.
21 689~5
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TABLE 2.1
Metal Salt x 9/9 Binder Uaterfastness Loss in Density X
H20 after nin. in ~ater
C M r K
La~N~)3 6H2 0.054 1 <1 5 9 8
Y(N~ )3 5H20 0.056 1 ~1 3 10 8
Ce(N03)~ 6H70 0.054 1 <1 6 9 13
M9(N3)2 6H2 0.032 c2 18 13 31 23
Mordant 1 3 0.8 c 12 30 33 27
I 0 Mordant 2 3 0.8 c 5 12 21 11
None 37 15 29 31
KEr: 1 Invention 2: Comparison 3 US 4,575,465
TABLE 2.2
1 5 Metal Salt x 9/9 Binder Light stability Loss in Density % H20 after ~OkJ At~as
C M Y K
La(NO~)1 6H20 0.054 1 1 13 30 39
Y(N03)~ 5H20 0.056 1 4 11 30 40
Ce(NO~)3 6H20 0.054 1 0 13 27 39
2 0 Mg(NO~)2 6H20 0.032 c2 9 13 32 31
Mordant 1 3 0.8 c 9 65 47 65
Mordant 2 3 0.8 c 5 93 50 87
None 9 14 39 37
KEr: 1 Invention 2: Comparison 3 ~'S 4,575,465
From the results given in Table 2.1 the efficacy
of the salts claimed in this invention in improving the
waterfastness of the dyes in printed images is evident.
It can further-more be, seen from table 2.1 and 2.2
that the efficacy in improving waterfastness by
cationic mordants according to the state of the art is
considerably lower than with the salts according to
this invention. What is however particularly evident
is that no deterioration of light stability occurs in
- 21689~5
-20-
presence of these salts where however the stability
against light is completely lost in presence of these
mordants.
Example 3
A coating mixture with a solid content of about
20% was prepared as follows, comprising:
1. Gelatine 2.49
(Stoess type 69 426)
2. Polyurethane 3.0g
(Daothan 1226 Hoechst, 40% aquous sol.)
3. Kaolin 10.09
4. Olin 10G 0 19
(Surfactant, Olin Corp.)
5. Crosslinker 0.059
(idem Example 1)
6- La(NO3)3~ H20 5 09
7. Uater to 1009
This mixture was bar coated onto an unsized high
quality paper in an amount of 1.2g/m2 (sample A). A
control (sample B) was prepared in an analogous way but
without the addition of Lanthanum salt. Waterfastness
and light stability were determined as described above.
The results are shown in Table 3.1.
TABLE 3.1
25Sample Uaterfastness: % LossLight Stability: % Loss (20 KJ Atlas)
(1 Minu-e Uater)
C M r K C M r K
A ~1 5 41 <1 3 56 27 27
B 13 25 ô7 31 7 67 50 60
The same samples were prepared but coated onto
heavy weight water colour paper. The results are shown
in Table 3.2.
21 6~95
TABLE 3.2
Sample Uaterf~st.ess: % LossLight Stability: % Loss
(1 Mirute Uater) (20 K~ Atlas)
C M Y K C M r K
A ~1 <1 14 <1 3 35 33 33
B 13 32 n 39 6 32 68 66
The results in Table 3.1 and 3.2 clearly show the
effect of the Lanthanum-salt on diffusion of the dyes
in water, also in the case where the claimed system is
applied to plain paper. Light stability is in both
cases improved when compared to the sample not
containing lanthanum salt.
Example 4
In this example lanthanum nitrate coatings were
applied directly to a substrate surface and were
evaluated for lightfastness and tendency to fade.
Four samples A, B, C & D were prepared. The
substrate used in all samples is a base paper sheet
coated with a silica and polyvinyl alcohol matrix.
Particular physical details of the support are as
follows:
24 lb base sheet tLock Haven - alkaline wood fiber matrix - 60/40 harduood/softwood)
25X CaC03 filler (precipitated H0/L0); internally sized ~ith ASA; surface sized with starch.
Physical properties of the base sheet include:
Basis Weight 24 lb
Caliper (mils O.ûOl inch) 4.0
Moisture (percent) 4.8~.5
Sheffield Smoothness (Sheffield units) 40
Porosity (Gurley) 60
The base sheet has a brightness (GE percent) of 90+ and opacity (percent) of 94.
3 0 Strength properties include: Stiffness (Gurley): 2 mgf; Tear MD & CD both S0~ 9 and
Mullen 30~ psi.
Silica coating: fumed silica 30 parts; precipita~ed silica 70 parts; polyvinyl alcohol
40 parts; dispersant and surfactants 3.1 parts. This coating is applied to the base sheet
in the range of 3-S lbs/3 000 ft.
21 6~'395
The silica coating is applied to the base sheet in
2 applications using a rod coater. A lanthanum nitrate
(water soluble salt of Group IIIb) is applied to the
surface of the silica coating in either a 4% (Sample B)
or a 3% (Sample C) aqueous solution using a rod coater.
Other Group IIIb metals that may be used include
scandium, yttrium, cerium, neodymium, praseodymium,
europium and ytterbium. The backside coating of the
substrate consists of a 0.5% calcium sterate solution
that is used as an anticurl agent and to reduce the
coefficient of friction.
The support without any coating (Sample A), and
coated with a quartinary amine dye fixative (Sample D),
were used as controls. The amine dye fixative coating
formulation includes a quarternised amine ester,
lauryldimethylbenzyl-ammoniumchloride, a polyamine salt
aqueous solution and a silicone derivative.
Liqhtfastness Evaluation
The effect of lanthanum nitrate on i-nk jet
printing ink color was evaluated before and after
lightfastness testing. Hewlett Packard 500 series ink
jet printing ink color was used in this example but any
other commercially available color inks are also
suitable for use in the invention. Samples A, B, C and
D were exposed to carbon arc light for periods of 1, 2
and 4 hours. Color readings (L*A*B*) were taken on
exposed and unexposed areas. The results are shown in
the Table 4.1 below.
21 6~995
-23-
TABLE 4.1
EFFECTS Of TOP COATING ON COLOR (L*A*B*)
CONDITION COLOR L* A* B*
A - CONTROL BLACK 34.43-12:04 - 6.49
B BLACK 40.70 - 8.31-~8.43
C BLACK 39.69 - 8.89- 7.13
D - CONTROL BLACK 32.43- 6.64 - 8.00
A - CONTROL CYAN 50.85-33.09 -54.05
B CYAN 50.05 -30.65-53.91
C CYAN 51.30 -32.51-53.59
D - CONTROL CYAN 49.71-27.07 -56.35
A - CONTROL YELLOU 89.78- 1.76 104.30
B rELLOU 89.31 - 0.53100.81
1 5 C rELLOU 89.66 - 1.70102.51
D - CONTROL YELLOU 88.28- 0.63 98.58
A - CONTROL MAGENTA 48.88 60.84 -53.20
B MAGENTA 47.56 57.56-54.58
C MAGENTA 47.59 59.24-54.94
D - CONTROL MAGENTA 50.67 59.80 -47.09
KEY: Sample A - Contro~: 2 lanthanum nitrate
Samp(e B - 0.651 9/m2 (0.4 lb/3,000 sq.ft.) ~anthanum nitrate
Samp~e C - 0.488 g/m (0.3 ~b/3,000 sq.ft.) ~anthanum nitrate
Sample D - Contro~: quartinary amine dye fixative
The tendency to fade of the coated samples above
were also evaluated after exposing treated papers to 1,
2 and 4 hours of carbon arc light. The results are
shown in the Table 4.2 below.
3 O TABLE 4.2
THE EFFECTS OF TOP COATING ON FADE
SAMPLE A (CONTROL)
3 5 COLOR1 HR. FADE D.E.2 HR. FADE D.E.4 HR. FADE D.E
BLACK 7.78 10.53 25.64
CYAN 13.91 18.58 34.54
YELLOU 3.10 3.71 6.39
MAGENTA 18.98 30.54 46.80
4 0 AVERAGE FADE - 18.29
2 1 6~9~5
-24- -
SAMPLE B ~4% La(No3)3)
COLOR 1 HR. FADE D.E.2 HR. FADE D.E. 4 HR. FADE D.E.
BLACK 3.79 6.11 11.73
CYAN 18.78 24.33 35.42
YELLOU 2.20 2.70 3.72
MAGENTA 20.13 29.58 44.97
AVERAGE FADE - 16.95
SAMPLE C ~3% La(No3)3)
COLOR 1 HR. FADE D.E.2 HR. FADE D.E. 4 HR. FADE D.E.
BLACK 5.28 7.74 16.39
CYAN 16.09 22.19 33.35
1 5 YELLO~ 3.0 3.86 5.78
MAGENTA 20.03 30.88 47.39
A~'ERAGE FADE - 17.66
SAMPLE D ~GONTROL~
2 0 COLOR 1 HR. FADE D.E.2 HR. FADE D.E. 4 HR. FADE D.E.
8LACK 4.03 6.31 17.45
CYAN 27.92 40.03 66.43
YELLO~ 6.32 8.52 22.41
MAGENTA 16.11 28.24 56.36
2 5 AV_RAGE FADE - 25.01
Results show the lanthanum nitrate coated sheets
exhibit less fade than the control (sample A) treated
with nothing at all. The amine coated support (sample
D) shows that the paper actually gets duller faster
than no coating (sample A).
Advantageously, the present invention provides
image receiving media for use in ink jet recording
which has excellant water resistance and lightfastness.
2 1 68995
-25-
It will be recognized by those skilled in the art that
the invention has wide application as a media which
allows the possibility to print images intended to
match those on silver halide pho.tographic material.
Further advantage is obtained by providing a.recording
medium which is suitable for office desk top publishing
of color graphics for ink jet printers.
Therefore, although the invention has been
described with reference to certain preferred
embodiments, it will be appreciated that other
composite structures and processes for their
fabrication may be devised, which are nevertheless
within the scope and spirit of the invention as defined
in the claims appended hereto.
