U.S. patent application number 11/429269 was filed with the patent office on 2006-09-14 for meltable ink composition.
Invention is credited to Richard Hendrikus Gerrit Brinkhuis, Roelof Hendrik Everhardus, Danny Hendrik Maria Hendricks, Marcus Petrus Leonardus Huinck, Erik Kelderman, Rudolf Antonius Maria Venderbosch.
Application Number | 20060205842 11/429269 |
Document ID | / |
Family ID | 29417507 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060205842 |
Kind Code |
A1 |
Everhardus; Roelof Hendrik ;
et al. |
September 14, 2006 |
Meltable ink composition
Abstract
A meltable ink composition, which is solid at room temperature
and liquid at elevated temperature, which ink composition is
suitable for use in an inkjet printer, the ink composition being
provided with a resin which contains a compound which is the
reaction product of a di-alkanolamine and a monofunctional aromatic
acid and optionally a difunctional acid.
Inventors: |
Everhardus; Roelof Hendrik;
(Lomm, NL) ; Kelderman; Erik; (Utrecht, NL)
; Huinck; Marcus Petrus Leonardus; (Herten, NL) ;
Hendricks; Danny Hendrik Maria; (Sittard, NL) ;
Venderbosch; Rudolf Antonius Maria; (Duiven, NL) ;
Brinkhuis; Richard Hendrikus Gerrit; (Zwolle, NL) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
29417507 |
Appl. No.: |
11/429269 |
Filed: |
May 8, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10443880 |
May 23, 2003 |
7084190 |
|
|
11429269 |
May 8, 2006 |
|
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Current U.S.
Class: |
523/160 |
Current CPC
Class: |
C09D 11/34 20130101 |
Class at
Publication: |
523/160 |
International
Class: |
C03C 17/00 20060101
C03C017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2002 |
NL |
1020682 |
Claims
1. An ink composition containing a vehicle composition and optional
additives, which ink composition is solid at room temperature and
liquid at elevated temperature, said ink composition being suitable
for use in an inkjet printer, the vehicle composition comprising a
resin, wherein the resin contains a compound which is the reaction
product of a di-alkanolamine and a mono-functional aromatic
acid.
2. The ink composition according to claim 1, wherein the compound
is the reaction product of di-isopropanolamine and benzoic acid,
the benzoic acid being optionally substituted with an alkyl and/or
alkoxy group.
3. The ink composition according to claim 2, wherein the benzoic
acid is substituted with a C1-C4 alkyl and/or a C1-C4 alkoxy
group.
4. The ink composition according to claim 1, wherein the ink
composition is also provided with a meltable crystalline
material.
5. The ink composition of claim 4, wherein the ink composition is
further provided with an amorphously solidifying monomer.
6. The ink composition according to claim 4, wherein the ink
composition is also provided with a viscosity controlling
agent.
7. The ink composition of claim 6, wherein the viscosity
controlling agent is a gelling agent.
Description
BACKGROUND OF THE INVENTION
[0001] This application is a Divisional of co-pending application
Ser. No. 10/443,880 filed on May 23, 2003, the entire contents of
which are hereby incorporated by reference and for which priority
is claimed under 35 U.S.C. .sctn. 120 and which application also
claims priority under 35 U.S.C. .sctn. 119(a) on Patent Application
No. 1020682 filed in The Netherlands on May 27, 2002, which is
herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an ink composition which is
solid at room temperature and liquid at elevated temperature, said
ink composition containing a resin and being suitable for use in an
inkjet printer.
RELATED ART
[0003] It is known to use resins in relatively large quantities in
meltable ink compositions (hot melt inks) for inkjet printers. Inks
of this kind are solid at room temperature and melt at elevated
temperature. Typical melting points are in the range of 60 to
120.degree. C. The melted inks are jetted at a temperature at which
they are thinly viscous, typically 100 to 160.degree. C., by means
of an inkjet printer as adequately known from the prior art. Resins
enable the ink to be sufficiently tough after cooling so that the
ink is more resistant to mechanical loads on the printed receiving
material, such as gumming, scratching and folding. Although
crystalline materials are generally harder, they are also much more
brittle, so that printed matter made using a mainly crystalline ink
composition is fairly sensitive to damage. The use of resins in ink
compositions also has the advantage that dyes can be dissolved
relatively well therein and pigments can be dispersed relatively
easily therein. In addition, resins have the advantage that after
solidification they are often transparent so that it is possible to
make color prints using subtractive color mixing. The disadvantage
of resins is that generally they are relatively viscous, even after
they have been softened at high temperature, and cannot therefore
be used in large quantities in hot melt inks.
[0004] Amorphously solidifying monomeric resins are known from U.S.
Pat. No. 6,071,986. Resins of this kind, which solidify completely
amorphously, have the advantage that they are not very viscous,
because of their relatively low molecular weight. The disadvantage
of these resins, however, is that their amorphous state is not
sufficiently stable. As a result, these resins will also
crystallise after a shorter or longer period. Even if these known
resins are used in an ink composition, there will be some
post-crystallization of the resins. This in turn has the result
that the quality of a printed image, i.e. after the corresponding
ink has solidified on the receiving material, will deteriorate in
the course of time.
[0005] Esters of 2,2'-biphenol and aromatic acids are known from EP
0 978 548. These are also examples of monomeric amorphously
solidifying resins. However, these resins still appear to have some
tendency to post-crystallization so that the properties of the
solidified ink change in the course of time, particularly when
printed receiving materials are stored under extreme conditions,
for example at relatively high temperatures.
SUMMARY OF THE INVENTION
[0006] The object of the present invention is to provide an ink
composition suitable for use in an inkjet printer, which ink
composition contains a resin having a low viscosity at the inkjet
printer operating temperature, which resin solidifies amorphously
and exhibits little post-crystallization if any. To this end, in a
first embodiment of the ink composition according to the present
invention the resins present therein contain a compound which is
the reaction product of a di-alkanolamine and a monofunctional
aromatic acid. It has surprisingly been found that a resin of this
kind which has a low melt viscosity (technically it is more correct
to refer to "softening viscosity" but this is unusual in the
technical area concerned) solidifies amorphously despite its low
molecular weight and exhibits practically no tendency to
post-crystallization.
[0007] According to a second embodiment of the present invention,
the ink composition contains resins which contain a compound which
is the reaction product of a di-alkanolamine and a monofunctional
aromatic acid and a difunctional acid. These resins also have a
very low melt viscosity and yet it solidifies amorphously and has
practically no tendency to post-crystallization. The resin
according to this second embodiment of the present invention often
contains a mixture of monomeric and oligomeric reaction products,
the precise composition of which depends, inter alia, on the ratio
of the reactants and the reaction conditions. Despite the fact that
the average molecular weight of this resin is higher than that of
the pure monomeric product according to the first embodiment of the
invention, it has been found that the melt viscosity is scarcely
higher, if at all. The amorphous state of this resin has been found
to be more stable than that of the first embodiment of the present
invention. This is probably a result of the fact that this resin is
often a mixture of related compounds.
[0008] From WO 96/10051 a polyamide resin is known which is
suitable for use in hot melt inks, said resin being the product of
the reaction between an amino alcohol, a monofunctional acid and a
di-acid. These resins have the disadvantage that they are waxy and
often not sufficiently transparent in the solidified state because
they are partially crystalline.
[0009] From U.S. Pat. No. 4,066,585 a synthetic polyamide resin is
known for intaglio and flexographic printing, which resin is the
condensation product of (1) an acid component comprising a
dimerised fatty acid and a monofunctional carboxylic acid and (2)
an amine component comprising a diamine and a diol and/or an
alkanol amine. These resins are also fairly waxy and often not
sufficiently transparent in the solidified state. These resins
therefore are hardly suitable for use in inkjet printers subject to
high requirements such as, for example, quality, speed,
reliability, variety of media for printing, and so on ("high
demand" printers).
[0010] U.S. Pat. No. 5,698,017 describes resins as a vehicle
material for an ink composition. These resins, e.g., oxazolines,
are the reaction product of an organic acid and an amino alcohol.
Resins of this kind have the disadvantage that they solidify in
crystalline form and therefore result in brittle ink layers on
media. Such layers have poor resistance to mechanical impacts such
as gumming, scratching and folding.
[0011] Progress in Organic Coatings, Volume 40 (2000), pages
203-214, describe hyperbranched polyester amides derived from
cyclic anhydrides and di-alkanolamines. These resins are described
as a constituent in liquid film-forming compositions for coating
applications. The use in solid meltable compositions which do not
form films is not described. Also, use in hot melt ink compositions
is not possible because the resins described are much too viscous
to be considered for such an application.
[0012] In another embodiment of the first-mentioned embodiment of
the present invention, the compound is the reaction product of
di-isopropanolamine and benzoic acid, the latter being optionally
substituted by an alkyl and/or alkoxy group. It has been found that
the compound of this ink composition is thermally very stable in
respect of visco-elastic properties. This is an advantage in the
printing of hot melt ink because the ink in the actual print head
generally has to experience a number of heating-up/cooling cycles
(printer on/off) before the ink is actually jetted. Also, this
compound has the advantage that it can be made without the addition
of a catalyst. This is also an advantage in use in a hot melt ink
since any contamination in the ink, no matter how small, may have a
negative influence on the functioning of the inkjet printer
(unstable jet behavior, nozzle clogging, wetting problems, and so
on).
[0013] In a further embodiment, the benzoic acid is substituted by
a C1-C4 alkyl and/or a C1-C4 alkoxy group. The physical properties
of the compound and hence of the resin can be adjusted more
accurately by the use of a substituted benzoic acid.
[0014] In a further embodiment of the present invention in which
the compound, for the same reasons as indicated hereinbefore, is
the reaction product of di-isopropanolamine and benzoic acid
optionally substituted by an alkyl and/or alkoxy group, the
difunctional acid is restricted to an organic acid containing an
aliphatic, aromatic or alicyclic main group (i.e. the longest
non-functional chain in the acid) with 12 carbon atoms at maximum.
It has been found that this leads to very stable compounds. In a
further embodiment, the difunctional acid contains an aliphatic or
alicyclic main group. It has been found that the compound has a
relatively low glass transition temperature (Tg) and a low melt
viscosity. In yet another embodiment, the difunctional acid is
selected from the group consisting of succinic acid, adipic acid
and cyclohexane dicarboxylic acid (cis and/or trans form). The use
of such acids results in ink compositions which are relatively
tough after cooling and thus very resistant to mechanical loads on
the image printed therewith.
[0015] Preferably, the ink compositions according to the present
invention contain a meltable crystalline material and optionally an
amorphously solidifying monomer as known from U.S. Pat. No.
6,071,986. In this way the properties of the ink composition can be
accurately adjusted and adapted, for example to the typical
properties of the printer, the selected receiving material, the
type of image, and so on.
[0016] Preferably, the ink composition contains a viscosity control
agent, for example a gelling agent as known from EP 1,067,175. In
this way, for example, the solidification behavior of the ink
composition can be accurately adjusted. In addition to such
viscosity control agents, the ink may contain additives such as UV
protectors, anti-oxidants and other preservative substances,
surfactants, and other additives as known from the prior art. As is
known for hot melt inks generally, inks of this kind can be used in
different types of inkjet printers and in combination with
different receiving materials. The receiving material used may, for
example, be a cheap plain paper because hot melt inks are generally
relatively insensitive to feathering. Alternatively, hot melt inks
can be transferred to receiving materials particularly suited for
inket uses, such as Bond paper, Laminate bond paper, EconoBond,
DuraBanner, Removable Tyvek, EconoVinyl and WaterFast Removable
Vinyl made by Colorspan; 600 016-1474-00 Smooth white bond,
016-1476-00 Photograde paper, 016-1478-00 Premium tracing/Backlit
paper, 016-1479-00 Backlit display film and 016-1496-00
Transparency film made by Tektronix; NC Photodry made by Zanders;
Photoglossy paper GP201 and High gloss photofilm made by Canon;
Photo quality glossy film SO41073 and SO 41071 made by Epson;
Premium water resistant H75000 and H75007 made by Felix Schoeller,
Ilfojet dry satin made by Ilford; 3290 IJP200 made by Sihl; backlit
IJM562 made by Oce. If required, the printing of hot melt ink on
such receiving materials may be combined with heating the receiving
material, particularly just before or after printing. In this way
it is often possible to obtain a specific degree of gloss, for
example matt, silk gloss or high gloss.
[0017] The invention will now be explained further by reference to
the following examples. Where these examples refer to a "part" of a
specific reactant, then unless otherwise indicated this means a
"molar part".
DETAILED DESCRIPTION OF THE INVENTION
[0018] Table 1 shows the reaction products of di-isopropanolamine
and aromatic acids;
[0019] Table 2 shows the reaction product of di-isopropanolamine,
an aromatic acid and a difunctional aliphatic acid, before and
after thermal loading; and
[0020] Table 3 shows ink compositions comprising the reaction
products of Tables 1 and. 2.
[0021] Example 1 shows a process for making reaction products as
indicated in Table 1.
[0022] Example 2 shows a process for making reaction products as
indicated in Table 2.
Table 1
[0023] Table 1 shows a number of reaction products of
di-isopropanolamine and various aromatic acids. The first product
is formed by the reaction of one part of di-isopropanolamine and
three parts of benzoic acid. The second product is formed by the
reaction of one part of di-isopropanolamine and three parts of
2-methylbenzoic acid. The third product is formed by the reaction
of two parts of di-isopropanolamine, three parts of 2-methylbenzoic
acid and three parts 4-t-butylbenzoic acid. The fourth product is
formed by the reaction of one part of di-isopropanolamine and three
parts 4-methoxybenzoic acid. The fifth and last product in this
Table is formed by the reaction of one part of di-isopropanolamine
and three parts 4-methylbenzoic acid.
[0024] The second column of Table 1 shows the glass transition
temperatures of the respective compounds. These are measured using
a Differential Scanning Calorimeter (DSC), namely the DSC-7 made by
Perkin Elmer, Norwalk, Conn. The glass transition temperature of a
resin in this test is equated with the onset of the bending point
of the enthalpy increase corresponding to the glass transition as
measured in the heating of a resin at 20.degree. C./min. To know
the thermal history of a resin, each resin is heated once, prior to
measurement, to above its glass transition temperature (20.degree.
C./min) and then rapidly cooled to room temperature
("quenching").
[0025] Finally, Table 1 gives, for each of the compounds, the
viscosity at three measurement temperatures. This viscosity is
measured using a steady shear viscosimeter, namely the DSR-200 made
by Rheometric Scientific, Piscataway, N.Y., using the known
plate-cone geometry. The viscosity follows from the ratio between
the stress required to shear the resin and the shearing speed in
equilibrium.
[0026] The reaction products given in this Table are monomeric
distinct compounds. They can be used as resins in a hot melt ink,
alone or in mixture with one or more other resins. These amorphous
compounds have a relatively low viscosity at typical jet
temperatures of 130-160.degree. C. and are thermally stable. Both
properties are favorable for use in a high-demand ink jet printer.
The compounds solidify amorphously and their amorphous state is
very stable. Even after a long time and under extreme conditions
(for example storage above the glass transition temperature) there
practically is no perceptible post-crystallization. As a result,
images printed with an ink composition in which these amorphous
compounds have been used as resin retain their initial quality for
a long period of time. TABLE-US-00001 TABLE 1 Reaction products of
di-isopropanolamine and aromatic acids. Tg Viscosity [mPa s] No
Reaction product of: [.degree. C.] (measuring temperature in
.degree. C.) 1 di-isopropanolamine (1 part) and 7 37 (110) 16 (130)
8 (150) benzoic acid (3 parts) 2 di-isopropanolamine (1 part) and 3
37 (110) 16 (130) 9 (150) 2-methylbenzoic acid (3 parts) 3
di-isopropanolamine (2 parts) and 14 127 (110) 39 (130) 17 (150)
2-methylbenzoic acid (3 parts) 4-t-butylbenzoic acid (3 parts) 4
di-isopropanolamine (1 part) and 23 91 (120) 34 (140) 16 (160)
4-methoxybenzoic acid (3 parts) 5 di-isopropanolamine (1 part) and
19 40 (120) 17 (140) 9 (160) 4-methylbenzoic acid (3 parts)
Table 2
[0027] Table 2 is an example of a compound according to the second
embodiment of the present invention. It relates to the reaction
product as indicated under Example 2. This product is not a
distinct compound but a mixture of monomeric and oligomeric
compounds in accordance with formula 1 (n=0, n=1, n=2, and so on),
this being the notation for the most probable molecule structure of
the resulting compounds. Despite its fairly high molecular weight,
this mixture nevertheless has a relatively low viscosity at the
typical jet temperatures.
[0028] The second row of Table 2 gives the same reaction product,
but in this case the product was thermally loaded for two weeks at
130.degree. C. in an oven. In the practice of inkjet printing, such
a loading would be expected only under extreme conditions (printer
continuously on but with hardly any printing if at all). It has
been found that the physical properties of the reaction product
after this heavy loading have scarcely altered. The viscosity has
dropped slightly and there is minimal brown coloration. Changes
could scarcely be perceived with NMR after loading. There was found
to be a small increase in the free benzoic acid (and this may
possibly explain the fall-off in viscosity). TABLE-US-00002 TABLE 2
Reaction product of di-isopropanolamine, an aromatic acid and
difunctional aliphatic acid, before and after thermal loading. Tg
Viscosity [mPa s] No Product [.degree. C.] (measuring temperature)
6 Resin in accordance 17 80 (120) 30 (140) 15 (160) with Example 2
6' Ditto, two weeks thermal 15 70 (120) 26 (140) 14 (160) loading
at 130.degree. C.
Table 3
[0029] Table 3 gives a number of ink compositions according to the
present invention. A hot melt ink can be made up, for example, by
combining one or more resins, for example as shown in Tables 1 and
2 of U.S. Pat. No. 6,071,986, Table 3a and 3b of EP 1 067 157 and
Table 1 of EP 0 978 548, with one or more crystalline materials,
for example as shown in Table 3 of U.S. Pat. No. 6,071,986, Table 2
of EP 1 067 157 and Table 3 of the Netherlands Patent Application
1017049, which is not a prior publication, and providing the same
with additives as dyes and/or pigments, anti-oxidants, wetting
agents, viscosity control agents (for example a gelling agent as
known from Table 1 of EP 1 067 157), UV-protectors, and so on.
[0030] Table 3 gives the basic composition or the vehicle
composition of three inks according to the present invention. Each
of the inks has a basic composition made up of 70% by weight of a
crystalline component and 30% of a resin according to the
invention. In each case in this example, the crystalline component
is a bis-ester of a low alkane diol (respectively 1,3-propanediol,
1,4-butanediol and 1,6-hexanediol) and an aromatic acid
(respectively 4-methoxybenzoic acid, 4-methylbenzoic acid and
4-methoxybenzoic acid). The resins are selected from the products
given in Tables 1 and 2. Each of these inks is provided with
viscosity control agents (not shown in the Table) namely 1% (one
part by weight per 100 parts by weight of ink), pentaerythritol
tetrabehenate and 1% bis-ester amide of 1,10-dodecanedi-acid and
3-methoxypropylamine. In addition, each of these inks contains a
dye, in this case 1.5% Waxoline Blue AP made by ICI. As further
additives the inks contain 0.1% Byk 309 (surfactant) and 0.5% Vanox
1005 (antioxidant). TABLE-US-00003 TABLE 3 Basic composition of
inks according to the invention Ink Crystalline component (70% by
weight) Resin (30% by weight) a) Bis-ester of propanediol and 4-
product no 6 (table 2) methoxybenzoic acid b) Bis-ester of
butanediol and 4- product no 4 (table 1) methylbenzoic acid c)
Bis-ester of hexanediol and 4- product no 1 (table 1)
methoxybenzoic acid
EXAMPLE 1
[0031] This Example describes a process for making product No. 1
from Table 1, the process also being suitable for making comparable
reaction products, particularly products 2 to 5 as shown in Table
1.
[0032] Synthesis of product 1 was carried out as follows. A 250 ml
3-neck round-bottom flask was provided with a mechanical agitator,
a thermometer and a DeanStark arrangement. 64.97 g (0.488 mol) of
di-isopropanolamine (Aldrich) and 178.70 g (1.463 mol) benzoic acid
(Aldrich) were placed in the flask. A small quantity of o-xylene
was also added, about 20 ml, as entraining agent to remove the
liberated water. The reaction mixture was heated to 180.degree. C.
and kept under a nitrogen atmosphere. After half an hour, the
temperature was again raised to 190.degree. C. After three hours,
the flask was evacuated to remove the o-xylene. When the o-xylene
had been removed, after about three-quarters of an hour, the
reaction mixture was drawn off. This mixture contained mainly
product 1 (Table 1), this product being identical to the formula 1
compound with n=0.
EXAMPLE 2
[0033] This Example describes a process used for making reaction
product 6 as indicated in Table 2, namely a reaction product of
di-isopropanolamine, benzoic acid and succinic acid anhydride. A 1
litre reaction flask was provided with a mechanical agitator, a
thermometer and a DeanStark arrangement. 261.06 g (1.960 mol) of
di-isopropanolamine (type S, BASF) 540.88 g (4.429 mol) benzoic
acid (Aldrich) and 69.69 g (0.696 mol) of succinic acid anhydride
(Aldrich) were placed in the flask. A small quantity of o-xylene,
about 60 ml, was added as entraining agent to remove the liberated
water. The reaction mixture was kept under a nitrogen atmosphere
and heated for 1 hour at 165.degree. C., whereafter the reaction
temperature was raised to 180.degree. C. After 6 hours the
temperature was reduced to 160.degree. C. and the flask was
evacuated to remove the o-xylene. It was possible to draw off the
reaction mixture after about 1 hour. Analysis showed that the
number-averaged molecular weight (M.sub.n) was 583 and the
weight-averaged molecular weight (M.sub.w) was 733. The ratio
between M.sub.w and M.sub.n (1.26) showed that there was a mixture
of compounds formed. The diagram below (formula 1) indicates what
compounds may form during the reaction between di-isopropanolamine,
benzoic acid and succinic acid (it should be noted that formula 1
is the most probable structure of the resulting compounds). The
reaction shows the formation of a mono-disperse compound. The ratio
in respect of reactants as indicated in the formula belongs to a
chosen value for n. This ratio need not necessarily be identical to
the ratio for the overall reaction, where in fact a mixture of
compounds with different values for n is formed. In the reaction
according to this example, a ratio has been chosen which is equal
to 2.82:6.36:1 (di-isopropanolamine:benzoic acid: succinic acid
anhydride). This means that there are 3.times.2.82=8.46 mol
equivalents of reactive NH/OH groups in the amine, as against
6.36+2.times.1.00=8.36 mol equivalents of acid groups in the
benzoic acid and anhydride. There is therefore only a very small
excess (about 1%) of di-isopropanolamine.
[0034] A GPC analysis showed that the mixture contained
approximately 45% by weight of the compound with n=0, about 40% by
weight of the compound with n=1 and about 15% by weight of
compounds with n=2 or higher. This is approximately equivalent to
60 mol. % of the compound with n=0; 30 mol. % of the compound with
n=1 and 10 mol. % of compound with n=2 or higher. ##STR1##
[0035] Other compounds for ink compositions according to the
invention can be made in a similar manner to that given in Examples
1 and 2. Changes in the ratio of the reactants or the type of
reactants (for example an anhydride instead of the acid and/or
vice-versa) may influence the synthesis. In this way, the skilled
man can obtain an ink composition tailored to his purpose.
[0036] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims.
* * * * *