Note: Descriptions are shown in the official language in which they were submitted.
. CA 022l7~2~ l997-l0-06
84-147P
~ ,,
AN INR JET INK RE~llv~ COATING COMPOSITION
Field of the Invention
The invention pertains to an ink jet ink receptive
coating composition, and to an ink jet recording media
prepared therewith by applying said coating composition
to a surface of a suitable base substrate.
Bac~4~ d of the Invention
Ink jet ink receptive coating layers used for ink
jet recording media have to meet a number of performance
requirements. These requirements include dry time,
color density, resolution, tack, color fidelity and
lightfastness, as well as cost. There are many
materials, both organic and inorganic, that have been
proposed for this application. Among them, cellulose
derivatives and alumina particulates have shown
promising performance, and cellulose derivatives have
been used alone or in combination with an inorganic
pigment other than alumina For example, U.S. Patent
4,555,437 describes a hydroxyethyl cellulose coating,
and U.S. Patent 4,575,465 describes a hydroxyprop~yl
cellulose coating.
Alumina has been extensively used as a filler or
pigment for ink jet recording media. For example, U.S.
Patent 4,780,3S6 discloses a two-layer coating that
contains silica or alumina with a particle size of 0.1
~m - 50 ~m, U.S. Patent 5,104,730 discloses- a coating
that contains pseudo-boehmite and polyvinyl alcohol,
U.S. Patent 5,264,275 discusses a two-layer coating that
. CA 02217~2~ 1997-10-06
contains pseudo-boehmite and polyvinyl alcohol/polyvinyl
P~rXolidone.
Summary of the Invention
An objective of the present invention is to provide
an ink jet ink receptive coating composition that can be
used in preparing ink jet rec~rding media, which upon
printing posses~ the improved combination of properties
of (i) good black ink optical density, (ii) low pigment
ink cracking, and (iii) good dry time.
In accordance with this objective, we herein
provide for:
(a) an inventive ink jet ink receptive coating
composition, (b) an inventive ink jet recording media
prepared therewith, and (c) an ink jet printing process
that utilizes the inventive ink jet recording media.
Specifically, we provide an ink jet ink receptive
coating composition that is useful in preparing an ink
jet recording media, wherein the coating composition -
when appropriately applied to a suitabie base substrate
and subsequently printed upon in an ink jet printing
process - provides an ink jet recording media that
offers the improved properties mentioned above.
More specifically, we provide for an inventive ink
jet ink receptive coating composition that is useful in
preparing an inventive ink jet recording media, where
the coating composition comprises a cellulose ether in
combination with an alumina particulate.
The cellulose ether used in the inventive coating
composition is preferably methylcellulose or a
hydroxyalkyl methylcellulose. It is also preferable
that the cellulose ether used in the inventive coating
composition possess a hydroxyalkyl content of 0~ to
about 32% and a methoxy content of about 16~ to about
32~, when tested according to ASTM D-3876 and ASTM D-
2363. Furthermore, it is preferable for the cellulose
ether to be present in the inventive coating
i . CA 02217~2~ 1997-10-06
compositions at a level of from about 50~ to about 95~
on--a weight/weight basis, based on the amount of solids
in the coating composition
The alumina particulate used in the inventive
coating compositions preferably has an average dispersed
particle size of about 10 nm to about 200 nm, and more
preferably about 30 nm to abou~ 170 nm.
The good ink jet printing performance that is
associated with the ink jet recording media of the
present invention, results from the fact that they
comprise a suitable substrate having on a surface
thereof an ink jet recording layer that is made from one
of the inventive ink jet ink receptive coating
compositions.
Detailed Description of the Invention
The following detailed description is provided as
an aid to those desiring to practice the present
invention. It is not to be construed as being unduly
limiting to the present inventive discovery, since those
of ordinary skill in the art will readily recognize that
the embodiments of the inventors' discovery disclosed
herein may be modified using standard techniques and
materials known in the art, without departing from the
spirit or scope of the present inventive discovery.
In arriving at the present invention, we have
discovered that several design parameters are important
to achieving the objective of the present invention.
These design parameters include:
(1) Inorganic oxides such as alumina should be used
in ink jet ink receptive coating compositions in
combination with polymeric binders to achieve optimal
performance
(2) Polyvinyl alcohol and polyvinyl pyrrolidone are
not appropriate for use as binders for some ink jet
recording media applications
CA 02217~2~ 1997-10-06
(3) The use of cellulose derivatives alone in
preparing ink jet ink receptive coating compositions
does not result in an ink jet recording media having the
desired combination of properties.
S (4) Not all cellulose derivatives are capable of
providing the desired properties in an ink jet recording
media, when present in the ~ink jet recording layer
thereof.
In order to meet the objective of the present
invention, our inventive ink jet ink receptive coating
compositions contain at least (i) a cellulose ether and
(ii) an alumina particulate.
The ink jet ink receptive coating compositions of
this invention preferably contain about 50~ to about 95~
of the cellulose ether therein, on a weight/weight
basis, based on the amount of solids in the coating
compositions.
The typical examples of cellulose ethers that are
useful in the present invention are methylcellulose and
hydroxyalkyl methylcelluloses, such as hydroxyethyl
methylcellulose, hydroxypropyl methylcellulose and
hydroxybutyl methylcellulose. Preferably, the cellulose
ether should have a hydroxyalkyl content of 0~ to about
32~ and a methoxyl content of about 16~ to about 32~.
The alumina particulates used in this invention
should possess an average dispersed particle size of
about 10 nm to about 200 nm, preferably about 30 nm to
about 170 nm. Typical examples of alumina particulates
that are useful in the present invention include
alumina, boehmite, pseudo-boehmite, aluminum hydrate and
aluminum oxide.
According to a preferred embodiment of the
invention, the ink jet ink receptive coating
compositions comprise about 0.01 to about lS~ by weight
of particulates therein (not including the
aforementioned alumina particulates), based on the
weight of the dry coating. In this way it is possible
. CA 02217~2~ 1997-10-06
to modify the surface properties of the ink jet
Eecording layer in the prepared ink jet recording media.
Examples of such particulates include inorganic
particulates, such as silica, kaolin, glass beads,
calcium carbonate, titanium oxide, barium sulfate,
aluminum silicate, zirconium oxide and tin oxide and
organic particulate such as polyolefins, polystyrene,
polyurethane, starch, poly(methyl methacrylate) and
polytetrafluoroethylene.
In practice, various additives may also be employed
in the ink jet ink receptive coating compositions of
this invention. These additives can include surface
active agents which control the wetting or spreading
action of coating solutions, antistatic agents,
suspending agents and acidic compounds to control pH of
the coating. Other additives may also be used, if so
desired.
The ink ~et ink receptive coating compositions of
this invention can be applied to a surface of a variety
of different base substrates (e.g., transparent
plastics, translucent plastics, matte plastics, opaque
plastics or papers), to prepare one of the inventive ink
jet recording media. Suitable polymeric materials for
use as the base substrate include polyester, cellulose
esters, polystyrene, polypropylene, poly(vinyl acetate),
polycarbonate, and the like. Poly(ethylene
terephthalate) film is a particularly preferred base
substrate. Further, while almost any paper can be used
as the base substrate, clay coated or polyolefin coated
papers are particularly preferred as base substrate
papers. The thickness of the base substrate is not
particularly restricted but should generally be in the
range of from about 1 to about 10 mils, preferably from
about 3.0 to about 5.0 mils. The base substrate may be
pretreated to enhance adhesion of the ink receptive
coating thereto.
CA 02217~2~ 1997-10-06
The thickness of the inventive coating is not
particularly restricted, but should generally be in the
range from about 2 grams per square meter to about 30
grams per square meter, on a surface of the base
substrate.
A surface of the base substrate that does not bear
the ink jet ink receptive coating may have a backing
material placed thereon in order to reduce electrostatic
charge and to reduce sheet-to-sheet friction and
sticking and reduce curl, if so desired. The backing
material may either be a polymeric coating, a polymer
film or paper.
Any number of coating methods may be employed to
coat the ink jet ink receptive coating composition onto
the surface of the base substrate. For example, roller
coating, blade coating, wire-bar coating, dip coating,
extrusion coating, air knife coating, curtain coating,
slide coating, doctor coating or gravure coating, may be
used and are well known in the art.
The following Examples are given merely as
illustrative of the invention and are not to be
considered as limiting thereto. In the Examples "parts"
refers to parts by weight, based on the total weight of
solids in the coating compositions.
EXAMPLE I
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Methylcellulosel 3.2 parts
Hydroxypropyl methylcellulose2 6.1 parts
Alumina Sol3 5.4 parts
Water 85.3 parts
Crosslinked poly(methyl methacrylate) 4 0 ~ 01 parts
1. Methocel A15LV, Dow Chemical Company
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2. Methocel K3LV, Dow Chemical Company
~_~ Dispal 23N4-20, Vista Chemical Company
4. Soken Chemical & Engineering Company, Ltd.
The coating is applied to a polyester film (ICI
Films) using a No. 24 Meyer rod, and the coating i~
dried at about 130~C for about' 2 minutes.
EXAMPLE I I
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatin~ Composition:
Hydroxypropyl methylcellulosel4.1 parts
Alumina Sol2 3.8 parts
Water 92.1 parts
Crosslinked poly(methyl methacrylate) 0.01 parts
1. Methocel K35LV, Dow Chemical Company
2. Dispal llN7-12, Vista Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 50 Meyer rod, and is dried at about
130~C for about 2 minutes.
EXAMPLE I I I
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Hydroxypropyl methylcellulose12.6 parts
Alumina Sol2 2.4 parts
Water 95.0 parts
Crosslinked poly (methyl methacrylate) 0.01 parts
1. Methocel KlOOLV, Dow Chemical Company
2. Nyacol AL20, Nyacol Products, Inc
CA 02217~2~ 1997-10-06
.
The coating is applied to a polyester film (ICI
Films) using a No. 70 Meyer rod, and is dried at about
,
130~C for about 2 minutes.
EXAMPLE IV
A coating composition is prepared according to the
following formulation: ~
Ink Receptive Coatinq Composition:
Methylcellulosel 8 parts
Alumina Sol2 6 parts
Water 86 parts
1. Methocel A15LV, Dow Chemical Company
2. Dispal 23N4-20, Vista Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 50 Meyer rod, and the coating is
dried at about 130~C for about 2 minutes.
COMPAR~TIVE EXAMPLE C - I
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Methylcellulose sodium salt1 4.1 parts
Alumina Sol2 3.7 parts
Water 92.2 parts
Crosslinked poly(methyl methacrylate) 0.01 parts
2S
1. Hercules, Inc.
2. Dispal 23N4-20, vista Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 50 Meyer rod, and is dried at about
130~C for about 2 minutes.
CA 02217~2~ 1997-10-06
COMPARATIVE EXAMPLE C-II
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Polyvinyl alcohol1 5.8 parts
Alumina Sol2 ~ 5.3 parts
Water 88.9 parts
Crosslinked poly(methyl methacrylate)0.01 parts
1. Airvol 823, Air Products and Chemicals, Inc.
2. Dispal 23N4-20, Vista Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 50 Meyer rod, and is dried at about
130~C for about 2 minutes.
COMPARATIVE EXAMPLE C-III
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Polyvinyl pyrrolidone1 5.7 parts
Alumina Sol2 5.2 parts
Water 89.1 parts
Crosslinked poly(methyl methacrylate)0.01 parts
1. PVP K-90, ISP Technologies, Inc.
2. Dispal llN7-12, Vista Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 50 Meyer rod, and is dried at about
130~C for about 2 minutes.
CA 02217525 1997-10-06
COMPARATIVE EXAMPLE C - IV
A coating composition is prepared according to the
following formulation:
Ink Rece~tive Coatinq Composition:
Hydroxypropyl methylcellulosel15 parts
Water 5 85 part~
Crosslinked poly(methyl methacrylate) 0.01 parts
1. Methocel K3LV, Dow Chemical Company
The coating is applied to a polyester film (ICI
Films) using a No. 24 Meyer rod, and is dried at about
130~C for about 2 minutes.
COMPAR~TIVE EXAMPLE C-V
A coating composition is prepared according to the
following formulation:
Ink Receptive Coatinq Composition:
Hydroxypropyl methylcellulose19.7 parts
Colloidal Silica Sol2 8.8 parts
Water 81.5 parts
Crosslinked poly(methyl methacrylate) 0.01 parts
1. Methocel K3LV, Dow Chemical Company
2. Ludox SK, Dupont Company
The coating is applied to a polyester film (ICI
Films) using a No. 24 Meyer rod, and is dried at about
130~C for about 2 minutes.
Each of the prepared ink jet recording media of
Examples I-III and Comparative Examples C-I to C-V, are
evaluated to determine whether they offer the following
improved combination of properties of (i) a good level
of black ink optlcal density, (ii) a low level of
CA 02217~2~ 1997-10-06
pigment ink cracking, and (iii) a good dry time, when
printed in an ink jet printing process.
The prepared ink jet recording media are evaluated
by printing on the ink jet recording surface thereof a
test plot, with a Hewlett Packard DESKJET 660C printer
using HP 51629A and HP 51649A ink cartridges. The black
ink is pigment based in the e~aluation.
The black ink optical density of each test sample
is measured with a MACBETH TD 904 densitometer (Macbeth
Process Measurements) using the beige filter setting.
A measurement is taken at three different locations
along a solid black image stripe. The average of the
three measurements is the black ink optical density.
The amount of pigmented ink cracking that is
associated with each sample is quantitatively rated with
a numerical scale of 0 to 5 (0=worst and 5=best). Each
Example and Comparative Example is imaged with a test
print. The Examples are given a numerical rating by
comparing the Examples to standard prints that exhibit
each level of ink cracking.
The dry time of each Example is measured by first
printing each example with the test plot. The Example
is then placed on top of a 20 lb. ream of XEROX 4200
paper. This is time zero (to)~ Thereafter, at thirty
second intervals, a sheet of white bond paper is placed
onto the surface of the Example, and then another 20 lb.
ream of XEROX 4200 paper is placed on top of the white
bond paper. After five seconds, the top ream of paper
and white bond paper is removed from on top of the
Example. The Example is dry when no transfer of ink
between the print and the white bond paper occurs, which
is termed the dry time (td_y)
The black ink optical density, ink cracking and dry
time (measured in minutes) for each Example and
Comparative Example is provided in Table I.
CA 022l7~2~ Iss7-l0-06
TABLE I
PE~FO~MANCE EVALUATION OF THE COATINGS
Black Ink
Optical Ink
Example Den~ity CrackingDry Ti~e
I 2.09 4 2.5
II 2.07 ' 4 2
III 2.11 4 2
IV 2.08 5 2.5
C-I 1.19 1 ~5
C-II 1.37 1 3.5
C-III 1.21 1 4.5
c-rv 1.08 1 3.5
C-V .93 0 3.5
As shown in Table I, Examples I to III all
exhibited improved black ink optical density, a low
level of pigment ink cracking, and a good dry time as
compared to the Comparative Examples C-I to C-V.
The pigmented black ink optical density is
inversely proportional to ink cracking, with pigment ink
cracking decreasing the black ink optical density. When
ink cracking is rated below 3, ink cracking is clearly
visible to the eye, and the ink jet recording media are
not suitable for many commercial applications.
The improved dry time of the examples allows a
higher throughput of the media in ink jet printing
devices.
Each of the patents and publications referred to
herein are incorporated by reference in their entirety
into the present application.
