U.S. patent application number 10/439428 was filed with the patent office on 2004-02-12 for novel fluorinated silicon (iv) phthalocyanines and naphthalocyanines for electrophoretic, magnetophoretic or electromagnetophoretic display.
Invention is credited to Li, Ying-Syi, Liang, Rong-Chang, Yang, Jin.
Application Number | 20040030125 10/439428 |
Document ID | / |
Family ID | 29550092 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040030125 |
Kind Code |
A1 |
Li, Ying-Syi ; et
al. |
February 12, 2004 |
Novel Fluorinated silicon (IV) phthalocyanines and
naphthalocyanines for electrophoretic, magnetophoretic or
electromagnetophoretic display
Abstract
This invention relates to stable colorants of high extinction
coefficient and high solubility or dispersibility for an
electrophoretic, magnetophoretic or electromagnetophoretic display.
More particularly, it relates to stable colorants for a
microcup-based electrophoretic or electromagnetophoretic display
the cells of which are filled with charged and/or magnetic
particles dispersed in a halogenated, preferably a fluorinated,
solvent. The use of the stable colorants allows the display to be
of superior contrast ratio and longevity, and suitable for
high-quality imagery applications.
Inventors: |
Li, Ying-Syi; (San Jose,
CA) ; Yang, Jin; (San Jose, CA) ; Liang,
Rong-Chang; (Cupertino, CA) |
Correspondence
Address: |
HELLER EHRMAN WHITE & MCAULIFFE LLP
275 MIDDLEFIELD ROAD
MENLO PARK
CA
94025-3506
US
|
Family ID: |
29550092 |
Appl. No.: |
10/439428 |
Filed: |
May 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60381263 |
May 17, 2002 |
|
|
|
Current U.S.
Class: |
540/126 |
Current CPC
Class: |
C09B 47/14 20130101;
C09B 47/085 20130101; C07F 7/0838 20130101; C07F 7/06 20130101;
G02F 1/133377 20130101; G02F 1/167 20130101 |
Class at
Publication: |
540/126 |
International
Class: |
C09B 047/04; C09B
062/00; C07D 487/22 |
Claims
What is claimed is:
1. A fluorinated silicon phthalocyanine or silicon naphthalocyanine
compound represented by the following formulas: 17wherein: each n
is individually 0-4 for silicon phthalocyanine (I) or 0-6 for
silicon naphthalocyanine (II); R.sup.1 is independently R.sub.f-A-
(wherein R.sub.f is as defined below and A is a single bond,
--CH.sub.2O--, --CH.sub.2CH.sub.2O-- or --CO--), alkyl,
heteroalkyl, aryl, heteroaryl, heteroalkylaryl, alkyl-heteroaryl;
heteroarylalkyl, aryl-heteroalkyl R'O--, R'S--, R'R"N--, R'CO--,
R'OCO--, R'COO--, R'CONR"--, R'R"NCO--, R'NHCONR"--,
R'SO.sub.2NR"-- or R'R"NSO.sub.2-- (in which R' and R" are
independently hydrogen, R.sub.f (as defined below), alkyl,
heteroalkyl, aryl, heteroaryl, heteroarylalkyl, aryl-heteroalkyl,
heteroalkylaryl or alkyl-heteroaryl) or halogenated, particularly
fluorinated derivatives thereof; Z is O or NR' wherein R' is
defined as above; R.sup.2 is hydrogen, R.sub.f (wherein Rf is as
defined below and B is a single bond, --CH.sub.2-- or
--CH.sub.2CH.sub.2--), alkyl, heteroalkyl or halogenated,
particularly fluorinated derivatives thereof, or
--SiR.sup.3R.sup.4R.sup.- 5 wherein R.sup.3, R.sup.4, and R.sup.5
are independently an alkyl or fluoroalkyl group of 1 to 20 carbon
atoms or alkoxy or fluoralkoxy of 2 to 40 carbon atoms; R.sub.f is
a low molecular weight (100-100,000) fluorinated polymeric or
oligomeric moiety prepared from one or more types of the
fluorinated monomers, and where the fluorine content of the
compound is at least 20% by weight.
2. The compound of claim 1 wherein the fluorine content is at least
30% by weight.
3. The compound of claim 2 wherein the fluorine content is at least
50% by weight.
4. The compound of claim 1 wherein R.sub.f is prepared from one or
more types of the fluorinated monomers selected from a group
consisting of epoxide, hydrofuran, cyclolactone, cyclolactam,
acrylate, methacrylate, styrene, vinylether and vinylalkane.
5. The compound of claim 1 wherein A is --CH.sub.2O--,
--CH.sub.2CH.sub.2O-- or --CO--.
6. The compound of claim 1 wherein B is --CH.sub.2--.
7. The compound of claim 1 wherein n is 0-2.
8. The compound of claim 1 wherein R.sup.1 is an alkyl,
fluoroalkyl, alkoxy or fluoralkoxy group having from 1 to 20 carbon
atoms.
9. The compound of claim 1 wherein R.sup.1 is an alkyl,
fluoroalkyl, alkoxy or fluoralkoxy group having 1 to 12 carbon
atoms.
10. The compound of claim 1 wherein Z is oxygen.
11. The compound of claim 1 wherein R.sup.2 is hydrogen,
R.sub.f--CH.sub.2--, alkyl, fluoroalkyl or
--SiR.sup.3R.sup.4R.sup.5 wherein R.sup.3, R.sup.4 and R.sup.5 are
independently an alkyl group, a fluorinated alkyl chain of 6 to 12
carbon atoms or a fluorinated alkoxy of 6 to 18 carbon atoms.
12. The compound of claim 11 wherein R.sup.2 is
--SiR.sup.3R.sup.4R.sup.5 in which one, two or all three R.sup.3,
R.sup.4 and R.sup.5 are methyl.
13. The compound of claim 11 wherein the fluoroalkyl chain is
--(CH.sub.2).sub.2(CF.sub.2).sub.5CF.sub.3 or
--(CH.sub.2).sub.2(CF.sub.2- ).sub.7CF.sub.3.
14. The compound of claim 11 wherein the fluoroalkoxy is
--OCH.sub.2(CF.sub.2).sub.12CF.sub.3 or
--OCH.sub.2(CF.sub.2).sub.6CF.sub- .3.
15. The compound of claim 1 wherein Rf is a low molecular weight
(200-20,000) fluorinated polymer or oligomer.
16. The compound of claim 15 wherein R.sub.f is a low molecular
weight (400-10,000) fluorinated polymer or oligomer.
17. The compound of claim 15 wherein R.sub.f is perfluoropolyether
or hydrofluoropolyether.
18. The compound of claim 15 wherein R.sub.f is
poly(chlorotrifluoroethyle- ne).
19. The compound of claim 15 wherein R.sub.f is a polymeric chain
derived from fluorinated epoxides.
20. The compound of claim 19 wherein R.sub.f is
--CF(CF.sub.3)[OCF.sub.2CF- (CF.sub.3)].sub.nF.
21. The compound of claim 1 wherein n is 0, Z is oxygen and
R.sup.2--CH.sub.2CF(CF.sub.3)[OCF.sub.2CF(CF.sub.3)].sub.nF.
22. The compound of claim 1 wherein n is 0, Z is oxygen and R.sup.2
is --SiR.sup.3R.sup.4R.sup.5 in which R.sup.3 is
--(CH.sub.2).sub.2(CF.sub.2- ).sub.7CF.sub.3 and R.sup.4 and
R.sup.5 are both --OCH.sub.2(CF.sub.2).sub- .12CF.sub.3.
23. The compound of claim 1 wherein n is 0, Z is oxygen and R.sup.2
is --SiR.sup.3R.sup.4R.sup.5 in which R.sup.3, R.sup.4 and R.sup.5
are all --(CH.sub.2).sub.2(CF.sub.2).sub.5CF.sub.3.
24. The compound of claim 1 wherein n is 1, R.sup.1 is
n-C.sub.8F.sub.17, Z is oxygen and R.sup.2 is hydrogen.
25. The compound of claim 1 wherein n is 1, R.sup.1 is
n-C.sub.8F.sub.17, Z is oxygen and R.sup.2 is
--SiR.sup.3R.sup.4R.sup.5 in which R.sup.3 and R.sup.4 both methyl
and R.sup.5 is --(CH.sub.2).sub.2(CF.sub.2).sub.7CF.s- ub.3.
26. A display composition comprising pigment particles dispersed in
a solvent colored by a silicon phthalocyanine compound, a silicon
naphthalocyanine compound or a mixture thereof, represented by the
following formulas: 18wherein: each n is individually 0-4 for
silicon phthalocyanine (I) or 0-6 for silicon naphthalocyanine
(II); R.sup.1 is independently R.sub.f-A- (wherein R.sub.f is as
defined below and A is a single bond, --CH.sub.2O--,
--CH.sub.2CH.sub.2O-- or --CO--), alkyl, heteroalkyl, aryl,
heteroaryl, heteroalkylaryl, alkyl-heteroaryl, heteroarylalkyl,
aryl-heteroalkyl, R'O--, R'S--, R'R"N--, R'CO--, R'OCO--, R'COO--,
R'CONR"--, R'R"NCO--, R'NHCONR"--, R'SO.sub.2NR"-- or
R'R"NSO.sub.2-- (in which R' and R" are independently hydrogen,
R.sub.f (as defined below), alkyl, heteroalkyl, aryl, heteroaryl,
heteroarylalkyl, aryl-heteroalkyl, heteroalkylaryl or
alkyl-heteroaryl) or halogenated, particularly fluorinated
derivatives thereof; Z is O or NR' wherein R' is defined as above;
R.sup.2 is hydrogen, R.sub.F--B-- (wherein R.sub.f is as defined
below and B is a single bond, --CH.sub.2-- or
--CH.sub.2CH.sub.2--), alkyl, heteroalkyl or halogenated,
particularly fluorinated derivatives thereof, or
--SiR.sup.3R.sup.4R.sup.5 wherein R.sup.3, R.sup.4, and R.sup.5 are
independently an alkyl or fluoroalkyl group of 1 to 20 carbon atoms
or alkoxy or fluoralkoxy of 2 to 40 carbon atoms; and R.sub.f is a
low molecular weight (100-100,000) fluorinated polymeric or
oligomeric moiety prepared from one or more types of the
fluorinated monomers and where the fluorine content of the compound
is at least 20% by weight.
27. The display composition of claim 26 comprising a mixture of a
fluorinated silicon phthalocyanine and a fluorinated silicon
naphthalocyanine of claim 1.
28. The display composition of claim 26 further comprising a
fluorinated non-silicon phthalocyanine dye.
29. The display composition of claim 28 wherein said fluorinated
non-silicon phthalocyanine dye is a fluorinated metal
phthalocyanine dye.
30. The display composition of claim 29 wherein said metal is Cu,
Mg or Zn.
31. The display composition of claim 30 wherein said metal is
Cu.
32. The display composition of claim 31 wherein the ratio of the
fluorinated silicon phthalocyanine or the fluorinated silicon
naphthalocyanine to the fluorinated copper phthalocyanine dye is
1/10 to 10/1.
33. The display composition of claim 31 wherein the ratio of the
fluorinated silicon phthalocyanine or the fluorinated silicon
naphthalocyanine to the fluorinated copper phthalocyanine dye is
1/5 to 5/1.
34. The display composition of claim 31 wherein the ratio of the
fluorinated silicon phthalocyanine or the fluorinated silicon
naphthalocyanine to the fluorinated copper phthalocyanine dye is
1/3 to 3/1.
35. The display composition of claim 26 wherein said pigment
particles are charged and/or magnetic.
36. The display composition of claim 35 wherein said pigment is
TiO.sub.2.
37. The display composition of claim 26 wherein said pigment is
density matched to the solvent by coating or
microencapsulation.
38. The display composition of claim 26 wherein said solvent is
selected from a group consisting of perfluoroalkanes,
perfluorocycloalkanes, perfluoroarylalkanes, perfluoro-tert-amines,
perfluoropolyethers, hydrofluoropolyethers and
poly(chlorotrifluoroethylene).
39. The display composition of claim 38 wherein said
perfluoropolyethers and hydrofluoropolyethers are selected from a
group consisting of Ausimont HT-170, HT-200, HT-230, ZT-180 and
Dupont trifluoro(trifluoromethyl)-oxirane homopolymers K-6 and K-7
fluids.
40. A electrophoretic, magnetophoretic or electromagnetophoretic
display comprising display cells filled with a display composition
which comprises pigment particles dispersed in a solvent colored by
a silicon phthalocyanine or silicon naphthalocyanine compound
represented by the following formulas: 19wherein: each n is
individually 0-4 for silicon phthalocyanine (I) or 0-6 for silicon
naphthalocyanine (II); R.sup.1 is independently R.sub.f-A- (wherein
R.sub.f is as defined below and A is a single bond, --CH.sub.2O--,
--CH.sub.2CH.sub.2-- or --CO--), alkyl, heteroalkyl, aryl,
heteroaryl, heteroalkylaryl, alkyl-heteroaryl, heteroarylalkyl,
aryl-heteroalkyl, R'O--, R', R'R"N--, R'CO--, R'OCO--, R'COO--,
R'CONR"--, R'R"NCO--, R'NHCONR"--, R'SO.sub.2NR"-- or
R'R"NSO.sub.2-- (in which R' and R" are independently hydrogen,
R.sub.f (as defined below), alkyl, heteroalkyl, aryl, heteroaryl,
heteroarylalkyl, aryl-heteroalkyl, heteroalkylaryl or
alkyl-heteroaryl) or halogenated, particularly fluorinated
derivatives thereof; Z is O or NR' wherein R' is defined as above;
R.sup.2 is hydrogen, R.sub.f--B-- (wherein R.sub.f is as defined
below and B is a single bond, --CH.sub.2-- or
--CH.sub.2CH.sub.2--), alkyl, heteroalkyl or halogenated,
particularly fluorinated derivatives thereof, or
--SiR.sup.3R.sup.4R.sup.5 wherein R.sup.3, R.sup.4, and R.sup.5 are
independently an alkyl or fluoroalkyl group of 1 to 20 carbon atoms
or alkoxy or fluoralkoxy of 2 to 40 carbon atoms; and R.sub.f is a
low molecular weight (100-100,000) fluorinated polymeric or
oligomeric moiety prepared from one or more types of the
fluorinated monomers and where the fluorine content of the compound
is at least 20% by weight.
41. The display of claim 40 wherein said cells are prepared by the
microcup technology.
42. The display of claim 41 wherein said cells are individually
sealed with a polymeric sealing layer.
43. The display of claim 42 wherein said polymeric sealing layer is
formed from a composition comprising a material selected from a
group consisting of thermoplastics, thermosets and precursors
thereof.
44. A process of the preparation of a silicone phthalocyanine or
naphthalocyanine compound represented by the following formulas:
20wherein: each n is individually 0-4 for silicon phthalocyanine
(I) or 0-6 for silicon naphthalocyanine (II); R.sup.1 is
independently R.sub.f-A- (wherein R.sub.f is as defined below and A
is a single bond, --CH.sub.2O--, --CH.sub.2CH.sub.2O-- or --CO--),
alkyl, heteroalkyl, aryl, heteroaryl, heteroalkylaryl,
alkyl-heteroaryl, heteroarylalkyl, aryl-heteroalkyl, R'O--, R'S--,
R'R"N--, R'CO--, R'OCO--, R'COO--, R'CONR"--, R'R"NCO--,
R'NHCONR"--, R'SO.sub.2NR"-- or R'R"NSO.sub.2-- (in which R' and R"
are independently hydrogen, R.sub.f (as defined below), alkyl,
heteroalkyl, aryl, heteroaryl, heteroarylalkyl, aryl-heteroalkyl,
heteroalkylaryl or alkyl-heteroaryl) or halogenated, particularly
fluorinated derivatives thereof; Z is 0 or NR' wherein R' is
defined as above; R.sup.2 is hydrogen, R.sub.f--B-- (wherein
R.sub.f is as defined below and B is a single bond, --CH.sub.2-- or
--CH.sub.2CH2--), alkyl, heteroalkyl or halogenated, particularly
fluorinated derivatives thereof, or --SiR.sup.3R.sup.4R.sup.5
wherein R3, R.sup.4, and R.sup.5 are independently an alkyl or
fluoroalkyl group of 1 to 20 carbon atoms or alkoxy or fluoralkoxy
of 2 to 40 carbon atoms; and R.sub.f is a low molecular weight
(100-100,000) fluorinated polymeric or oligomeric moiety prepared
from one or more types of the fluorinated monomers and where the
fluorine content of the compound is at least 20% by weight, which
process comprises: a) reacting a compound of Formula III or IV
21wherein n and R.sup.1 are as defined above and X is halogen or
hydroxy with a compound of Formula V Y--Z--R.sup.2 (V) wherein Z
and R.sup.2 is as defined above and Y is hydrogen or an alkali
metal to form a compound of Formula I or II respectively, or b)
reacting a compound of Formula III or IV wherein n and R.sup.1 are
as defined above and X is hydroxy with SiR.sup.3R.sup.4R.sup.5Cl or
SiR.sup.3R.sup.4R.sup.5Br wherein R.sup.3, R.sup.4 and R.sup.5 are
as defined above to form a compound of Formula I wherein Z is
oxygen and R.sup.2 is --SiR.sup.3R.sup.4R.sup.5 in which R.sup.3,
R.sup.4 and R.sup.5 are as defined above; or c) reacting a compound
of Formula III or IV wherein n and R.sup.1 are as defined above and
X is hydroxy with SiR.sup.3Cl.sub.3, followed by R.sup.4OH, wherein
R.sup.3 and R.sup.4 are as defined above to form a compound of
Formula I wherein Z is oxygen and R.sup.2 is
--SiR.sup.3R.sup.4R.sup.5 in which R.sup.3 and R.sup.4 are as
defined above and R.sup.5 is the same as R.sup.4; or d) converting
a compound of Formula I or II wherein n and R.sup.1 are as defined
above and Z--R.sup.2 is a group convertible to a hydroxy group to
form a compound of Formula I or II wherein Z is oxygen and R.sup.2
is hydrogen; or e) converting a compound of Formula I or II wherein
n is 0 to a compound of Formula I or II wherein n is at least 1 and
R.sup.1 is other than hydrogen.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/381,263 filed May 17, 2002, which is
incorporated herein by reference in its entirety.
BACKGROUND 1. Field of the Invention
[0002] This invention relates to stable colorants of high
extinction coefficient and high solubility or dispersibility for an
electrophoretic, magnetophoretic or electromagnetophoretic display.
More particularly, it relates to stable colorants for a
microcup-based electrophoretic, magnetophoretic or
electromagnetophoretic display the cells of which are filled with
charged and/or magnetic particles dispersed in a halogenated,
preferably a fluorinated, solvent. The use of the stable colorants
allows the display to be of superior contrast ratio and longevity,
and suitable for high-quality imagery applications. 2. Brief
Description of Related Art
[0003] The electrophoretic display (EPD) is a non-emissive device
based on the electrophoresis phenomenon influencing the migration
of charged pigment particles in a solvent, preferably a colored
dielectric solvent. This type of display was first proposed in
1969. An EPD typically comprises a pair of opposed, spaced-apart
plate-like electrodes, with spacers predetermining a certain
distance between the electrodes. At least one of the electrodes,
typically on the viewing side, is transparent. For the passive type
of EPDs, row and column electrodes on the top (the viewing side)
and bottom plates respectively, are needed to drive the displays.
In contrast, an array of thin film transistors (TFTs) on the bottom
plate and a common, non-patterned transparent conductor plate on
the top viewing substrate are required for the active type
EPDs.
[0004] An electrophoretic fluid composed of a colored dielectric
solvent with charged pigment particles dispersed therein is
enclosed between the two electrodes. When a voltage difference is
imposed between the two electrodes, the pigment particles migrate
by attraction to the plate of polarity opposite that of the pigment
particles. Thus, the color showing at the transparent plate,
determined by selectively charging the plates, can be either the
color of the solvent or the color of the pigment particles.
Reversal of plate polarity will cause the particles to migrate back
to the opposite plate, thereby reversing the color. Intermediate
color density (or shades of gray) due to intermediate pigment
density at the transparent plate may be obtained by controlling the
plate charge through a range of voltages or pulsing time.
[0005] EPDs of different pixel or cell structures have been
reported previously, for example, the partition-type EPD (M. A.
Hopper and V. Novotny, IEEE Trans. Electr. Dev., Vol. ED 26, No. 8,
pp.1148-1152 (1979)) and the microencapsulated EPD (U.S. Pat. Nos.
5,961,804 and 5,930,026).
[0006] An improved EPD technology was recently disclosed in
co-pending applications, U.S. Ser. No. 09/518,488, filed on Mar. 3,
2000 (corresponding to WO 01/67170), U.S. Ser. No. 09/606,654,
filed on Jun. 28, 2000 (corresponding to WO02/01281) and U.S. Ser.
No. 09/784,972, filed on Feb. 15, 2001 (corresponding to
WO02/65215), all of which are incorporated herein by reference. The
improved EPD comprises isolated cells formed from microcups and
filled with charged particles dispersed in a dielectric solvent.
The filled cells are individually sealed with a polymeric sealing
layer, preferably formed from a composition comprising a material
selected from a group consisting of thermoplastics, thermosets and
precursors thereof.
[0007] Other types of displays, namely magnetophoretic displays
(MPDs) and electromagnetophoretic displays (EMPDs), are disclosed
in U.S. Serial No. 60/367,325, filed on Mar. 21, 2002 and U.S.
Serial No. 60/375,299, filed on Apr. 23, 2002, the contents of both
are incorporated herein by reference in their entirety.
[0008] The magnetophoretic display generally comprises display
cells sandwiched between two layers of substrate and filled with a
magnetophoretic dispersion wherein the pigment particles are
magnetic but not charged. The display is driven by a magnetic
field. At least the substrate layer on the viewing side is
transparent.
[0009] In the electromagnetophoretic display, the display cells
sandwiched between two substrate layers are filled with an
electromagnetophoretic fluid wherein the pigment particles are both
charged and magnetic. One of the substrate layers, preferably on
the non-viewing side, is coated with a conductive layer facing the
filled display cells. The display is driven by a combination of
electric and magnetic fields. The substrate layer on the viewing
side is transparent.
[0010] For all types of displays, the dispersion contained within
the display cells is undoubtedly one of the most crucial parts of
the device. The dispersion, as stated earlier, usually is composed
of pigment particles dispersed in a colored dielectric solvent or
solvent mixture. The composition of the dispersion determines, to a
large extent, the longevity, contrast ratio, switching rate,
response waveform and bistability of the device. In an ideal
dispersion, the dispersed pigment particles remain separate and do
not aggregate or flocculate under all operating conditions.
Furthermore, all components in the dispersion must be chemically
and electrochemically stable and compatible not only with each
other but also with the other materials present in a display, such
as the electrodes and sealing and substrate materials.
[0011] The dispersing medium may be colored by dissolving or
dispersing a dye or colorant in the dielectric solvent or solvent
mixture.
[0012] Halogenated solvents of high specific gravity have been
widely used in EPD applications, particularly in those involving an
inorganic pigment, such as TiO.sub.2, as the charged whitening or
coloring particles. The halogenated solvents of high specific
gravity are very useful in reducing the rate of sedimentation of
the pigment particles in the solvent. Fluorinated solvents are
among the most preferred because they are chemically stable and
environmentally friendly.
[0013] However, most dyes or pigments are not soluble in
fluorinated solvents, particularly not in high boiling-point
perfluorinated solvents. For example, phthalocyanines are highly
desirable colorants due to their high extinction coefficients,
narrow absorption bands and chemical stability; but they are
normally insoluble in most solvents, and are particularly insoluble
in fluorinated solvents. Therefore, displays based on fluorinated
dielectric solvents colored by this type of dyes typically show
poor shelf-life stability, contrast ratio and switching
performance.
[0014] Certain soluble fluorinated copper phthalocyanine dyes are
disclosed in U.S. Pat. No. 3,281,426 (1966). The process for the
preparation of these dyes involves heating a mixture of an aromatic
starting compound and a perfluoroalkyliodide at a temperature in
the range of from 200.degree. C. to 350.degree. C. The reaction is
performed in an autoclave or a pressure ampoule due to the pressure
developed. This synthesis involves complicated reaction conditions
(e.g., high pressure and temperature) and long reaction time and
has a low yield. Other phthalocyanine derivatives (U.S. Pat. Nos.
6,043,355 and 5,932,721) show improved solubility in various
organic solvents or even in water, but not in highly fluorinated
solvents.
[0015] Thus, there is a need for stable dyes or colorants that
exhibit high solubility or dispersibility in halogenated,
particularly fluorinated, dielectric solvents for use in display
applications. The dyes or colorants should also have a high
extinction coefficient, narrow adsorption bands and chemical or
electrochemical stability, and can be manufactured in high yields
at low cost.
SUMMARY OF THE INVENTION
[0016] The first aspect of the present invention is directed to a
group of novel fluorinated silicon phthalocyanine and
naphthalocyanine dyes which comprise a fluorine content of at least
20% by weight, preferably at least 30% by weight and more
preferably at least 50% by weight.
[0017] A second aspect of the invention is directed to a display
composition which comprises one or more fluorinated silicon
phthalocyanine or naphthalocyanine dye of the first aspect of the
invention as a colorant dissolved or dispersed in a dielectric
solvent or solvent mixture, particularly in a fluorinated
dielectric solvent or solvent mixture in which pigment particles
are suspended.
[0018] A third aspect of the invention is directed to a display
composition of the second aspect of the invention further
comprising a non-silicon phthalocyanine or naphthalocyanine dye,
preferably a fluorinated metal phthalocyanine dye in addition to
the dyes of the first aspect of the invention.
[0019] A fourth aspect of the invention is directed to an
electrophoretic, magnetophoretic or electromagnetophoretic display
the cells of which are filled with a display composition of the
second or third aspect of the invention.
[0020] A fifth aspect of the invention is directed to a
microcup-based display which comprises sealed display cells filled
with a display composition of the second or third aspect of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] I. Definitions
[0022] Unless defined otherwise in this specification, all
technical terms are used herein according to their conventional
definitions as they are commonly used and understood by those of
ordinary skill in the art.
[0023] The term "alkyl" is broader than the customary chemical
definition and refers to a linear, branched or cyclic hydrocarbon
radical. Unless otherwise indicated, the alkyl group may have 1 to
20, preferably 1 to 12 carbon atoms. For example, it may be methyl,
ethyl, cyclohexyl, octyl, n-decyl or the like which is optionally
unsaturated, such as ethenyl, 3-hexenyl or the like.
[0024] The term "heteroalkyl" refers an "alkyl" as defined above in
which one or more carbon atoms are replaced by O, S or N.
[0025] The term "alkoxy" refers to the group --O--R wherein R is an
alkyl as defined above. The term "heteroalkoxy" refers to the group
--O--R wherein R is a heteroalkyl as defined above.
[0026] The term "aryl", as in "aryl", "arylalkyl" or "alkylaryl",
refers to an organic radical derived from an aromatic hydrocarbon
having 6 to 18 carbon atoms including, but not limited to, phenyl,
naphthyl, anthracenyl and the like.
[0027] The term "heteroaryl" refers to an organic radical derived
from an aromatic hydrocarbon in which one or more of the ring
carbon atoms are replaced by O, S or N, such as pyridyl, thienyl,
furanyl or pyrrolyl.
[0028] The term "halogenated" or "fluorinated" refers to a moiety
which is partially or completely substituted with halogen atoms or
fluorine atoms, respectively.
[0029] II. Fluorinated Silicon Phthalocyanine and Naphthalocyanine
Dyes
[0030] The novel fluorinated silicon phthalocyanine (I) and
naphthalocyanine (11) dyes of the present invention may be
expressed by the following formulas: 1
[0031] wherein:
[0032] each n is individually 0-4 for silicon phthalocyanine (1) or
0-6 for silicon naphthalocyanine (11);
[0033] R.sup.1 is independently R.sub.f-A- (wherein R.sub.f is as
defined below and A is a single bond, --CH.sub.2O--,
H.sub.2CH.sub.2O-- or --CO--), alkyl, heteroalkyl, aryl,
heteroaryl, heteroalkylaryl, alkyl-heteroaryl, heteroarylalkyl
aryl-heteroalkyl, R'O--, R'S--, R'R"N--, R'CO--, R'OCO--, R'COO--,
R'CONR"--, R'R"NCO--, R'NHCONR"--, R'SO.sub.2NR"-- or R'R"NSO-- (in
which R' and R" are independently hydrogen, R.sub.f (as defined
below), alkyl, heteroalkyl, aryl, heteroaryl, heteroarylalkyl,
aryl-heteroalkyl, heteroalkyaryl or alkyl-heteroaryl) or
halogenated, particularly fluorinated derivatives thereof;
[0034] Z is O or NR' wherein R' is defined as above;
[0035] R.sup.2 is hydrogen, R.sub.f--B-- (wherein R.sub.f is as
defined below and B is a single bond, --CH.sub.2-- or
--CH.sub.2CH.sub.2--), alkyl, heteroalkyl or halogenated,
particularly fluorinated derivatives thereof, or
--SiR.sup.3R.sup.4R.sup.5 wherein R.sup.3, R.sup.4, and R.sup.5 are
independently an alkyl or fluoroalkyl group of 1 to 20 carbon atoms
or alkoxy or fluoroalkoxy of 2 to 40 carbon atoms; and
[0036] R.sub.f is a low molecular weight (100-100,000) fluorinated
polymeric or oligomeric moiety prepared from one or more types of
fluorinated monomers.
[0037] Useful fluorinated monomers may include, but are not limited
to, epoxide, hydrofuran, cyclolactone, cyclolactam, acrylate,
methacrylate, styrene, vinylether and vinylalkane.
[0038] The substituents, R.sup.1, R.sup.2, R.sup.3, R.sup.4,
R.sup.5, R.sub.f, and n are so selected that the total fluorine
content of the silicon phthalocyanine dye is at least 20%,
preferably at least 30% and more preferably at least 50%, by weight
of the dye molecule.
[0039] It will be recognized that when the preparation of the
compounds involves the reaction of a formed
phthalocyanine/naphthalocyanine or silicon
phthalocyanine/naphthalocyanine with a reagent that inserts R.sup.1
groups, the resulting product may be a mixture of compounds having
different degrees of R.sup.1 substitution on the
phthalocyanine/naphthalocyanine rings, so that n, when not 0, may
be different on each of the phenyl or naphthyl moiety within a
compound; and it will also be recognized that substitution may
occur at different positions on the different phenyl/naphthyl rings
of the phthalocyanine/naphthalocyanine; and all such compounds are
within the scope of the present invention. In addition, when n is
not 0, not all R.sup.1 groups need be the same, either within the
compound as a whole or even on a particular phenyl or naphthyl
moiety within a compound.
[0040] Preferred Embodiments
[0041] In the compounds of Formula (I) and (II), n is preferably
0-2, preferably 0-1. For example, n may be 0.
[0042] Each R.sup.1 is independently an alkyl or alkoxy group,
preferably a halogenated alkyl or alkoxy group, more preferably a
fluorinated alkyl or alkoxy group. Especially preferred R.sup.1
groups are fluorinated, especially completely fluorinated alkyl of
1 to 12 carbon atoms, more preferably 6 to 10 carbon atoms.
[0043] The substituent, Z, is preferably oxygen.
[0044] The substituent, R.sup.2, is preferably hydrogen,
R.sub.f--CH.sub.2--, alkyl and fluoroalkyl as defined above or
--SiR.sup.3R.sup.4R.sup.5 wherein R.sup.3, R.sup.4 and R.sup.5 are
independently an alkyl group such as methyl, a fluorinated alkyl
chain of 6 to 12 carbon atoms or a fluorinated alkoxy of 6 to 18
carbon atoms. In one embodiment, R.sup.3, R.sup.4 and R.sup.5 may
be independently an alkyl, a fluorinated alkyl such as
--(CH.sub.2).sub.2(CF.sub.2).sub.5CF.s- ub.3 or
--(CH.sub.2).sub.2(CF.sub.2).sub.7CF.sub.3 or a fluorinated alkoxy
such as --OCH.sub.2(CF.sub.2).sub.12CF.sub.3 or
--OCH.sub.2(CF.sub.2).sub- .6CF.sub.3.
[0045] R.sub.f is as defined above and is preferably a low
molecular weight (200-20,000, more preferably 400-10,000)
fluorinated polymer or oligomer. Examples of R.sub.f may include
perfluoropolyether and hydrofluoropolyether derived from the
monomer, perfluoropropylene oxide, or from oligomers such as
Krytox.RTM. K-fluids (trifluorohomopolymer) from Dupont and HT or
ZT series from Ausimont; and poly(chlorotrifluoroethylene) derived
from the monomer, chlorotrifluoroethylene, or from oligomers such
as Halocarbon Oils from Halocarbon Product Corp. (River Edge,
N.J.).
[0046] In one embodiment, R.sub.f is a monovalent radical derived
from a halogenated, especially a fluorinated, optionally
substituted, alkylene or alkylene oxide homopolymer or copolymer
having a molecular weight between 200 and 20,000.
[0047] In another embodiment, R.sub.f may be expressed by the
following formula: 2
[0048] wherein the open substituent positions (not designated) on
the main chain of the formula can be the same or different and may
independently be selected from a group consisting of hydrogen,
halogen (especially fluorine), alkyl, aryl, alkylaryl, fluorinated
alkyl, fluorinated aryl, fluorinated alkylaryl, --OR.sup.6,
OCOR.sup.6, --COOR.sup.6, --CONR.sup.6R.sup.7 (wherein R.sup.6 and
R.sup.7 are independently hydrogen, alkyl, aryl, alkylaryl,
fluorinated alkyl, especially perfluoroalkyl, fluorinated aryl,
especially perfluorinated aryl) and substituted derivatives
thereof; Z.sub.1, Z.sub.2, and Z.sub.3 are independently oxygen or
absent; and a, b, and c are the weight fractions of the
corresponding repeating units and are independently in the range of
0-1 with their sum equal to 1.
[0049] In one embodiment, the open substituent positions on the
main chain of Formula (III) may be independently fluorine or
fluoroalkyl, such as --CF(CF.sub.3)[OCF.sub.2CF(CF.sub.3)].sub.nF
or the like
[0050] When R.sup.1 is R.sub.f-A-, A is preferably --CH.sub.2O--,
--CH.sub.2CH.sub.2O-- or --CO--. When R.sup.2 is R.sub.f--B--, B is
preferably --CH.sub.2--.
[0051] The dyes of the present invention are highly soluble or
dispersible in fluorinated solvents, and exhibit high extinction
coefficients and good thermal and light fastness. Therefore, they
are particularly suitable for use as colorants in displays. They
may also be used as colorants for color filters, coatings,
adhesives and lubricants.
[0052] III. Synthesis of Fluorinated Silicon Phthalocyanine
Dyes
[0053] The compounds of the present invention may be prepared
according to conventional methods. Most of the compounds in the
present invention may be synthesized according to the following
reaction scheme: 3
[0054] wherein n, R.sup.1, R.sup.2 and Z are as defined above;
[0055] X is halogen or hydroxy; and Y is hydrogen or an alkali
metal such as sodium, potassium or lithium.
[0056] The compounds of Formulas III and IV are commercially
available (for example, from Aldrich) or may be prepared by
commercially available compounds. The X substituent in Formula III
and Formula IV is preferably chlorine or hydroxy. The compound of
Formula (V) wherein Y is hydrogen can be converted to an alkali
salt by, for example, refluxing with an alkali metal in anhydrous
ether.
[0057] A compound of Formula I or II wherein Z is oxygen and
R.sup.2 is --SiR.sup.3R.sup.4R.sup.5 may be prepared by reacting a
compound of Formula III or IV wherein X is hydroxy with
SiR.sup.3R.sup.4R.sup.5Cl or SiR.sup.3R.sup.4R.sup.5Br. The Si
reagents are commercially available (for example, from Gelest) or
may be prepared according to Example 3A below. In general, these
reagents are prepared according to methods described in J. Org.
Chem., 1997, 62, 2917-2924.
[0058] Alternatively, the preparation of a compound of Formula I or
Formula II wherein Z is oxygen and R.sup.2 is
--SiR.sup.3R.sup.4R.sup.5 may be carried out in steps. For example,
a compound of Formula III wherein X is hydroxy may be first reacted
with SiR.sup.3Cl.sub.3; the intermediate compound thus obtained is
then reacted with a compound of R.sup.4OH to form a compound of
Formula I wherein R.sup.2 is --SiR.sup.3R.sup.4R.sup.5 in which
R.sup.3 and R.sup.4 are as defined above and R.sup.5 is the same as
R.sup.4. The reaction conditions of the two step process are
exemplified in Example 2 below.
[0059] The substituent, R.sup.1, on the ring structure may be added
on by conventional methods as demonstrated in Example 5 below.
[0060] IV. Display Compositions Containing the Fluorinated Silicon
Phthalocyanine or Naphthalocyanine Dye
[0061] The term "display composition" refers to an electrophoretic,
magnetophoretic or electromagnetophoretic dispersion.
[0062] The dyes of the present invention are highly soluble in
fluorinated solvents, particularly perfluorinated solvents and have
high extinction coefficients in the 500-700 nm region. A solvent
having low vapor pressure, low viscosity and a dielectric constant
in the range of about 1.5 to about 30, more preferably about 2 to
about 10, are generally needed as the dielectric solvent of the
electrophoretic fluid. Examples of suitable fluorinated solvents
for EPD applications include, but are not limited to, fluorinated
and perfluorinated solvents such as perfluoroalkanes or
perfluorocycloalkanes (e.g., perfluorodecalin),
perfluoroarylalkanes (e.g., perfluorotoluene or perfluoroxylene),
perfluoro-tert-amines, perfluoropolyethers such as those from
Galden/Fomblin and perfluoropolyethers HT series, and
hydrofluoropolyethers (ZT series) from Ausimont, FC-43
(heptacosafluorotributylamine), FC-70 (perfluorotri-n-pentylamine),
PF-5060 or PF-5060DL (perfluorohexane) from 3M Company (St. Paul,
Minn.), low molecular weight (preferably less than 50,000, more
preferably less than 20,000) polymers or oligomers such as
poly(perfluoropropylene oxide) from TCI America (Portland, Oreg.),
poly(chlorotrifluoroethylene) such as Halocarbon Oils from
Halocarbon Product Corp. (River Edge, N.J.), Krytox.RTM. K-fluids
(trifluorohomopolymer) from Dupont, and Demnum lubricating oils
from Daikin Industries. Perfluoropolyethers and
hydrofluoropolyethers such as Ausimont HT-170, HT-200, HT-230,
ZT-180 and Dupont trifluoro(trifluoromethyl)-oxirane homopolymers
(such as K-6 and K-7 fluids) are particularly useful.
[0063] The display composition may comprise one or more fluorinated
silicon phthalocyanine dye and fluorinated naphthalocyanine dye as
a colorant in a dielectric solvent, especially a fluorinated
dielectric solvent. The composition may further comprise a
fluorinated non-silicon phthalocyanine or naphthalocyanine dye,
particularly a fluorinated metal phthalocyanine or naphthalocyanine
dye to enhance the color saturation. The metal may be Cu, Mg or Zn.
These metal phthalocyanine dyes are available commercially or may
be synthesized according to U.S. Pat. No. 3,281,426.
[0064] The use of a mixture of a dye of the present invention and a
Cu phthalocyanine dye is preferable because the colorant mixture
increases the low temperature (particularly subzero C) latitude of
the display over that of a comparable display using only the
fluorinated Cu phthalocyanine dye. Without being limited by theory,
it is considered that this may be due to the higher solubility of
the present dye in the electrophoretic fluid. The solubility of the
present dye in a perfluorinated solvent such as HT-200 is about 3-5
wt % whereas the solubility of the Cu dye in the same solvent is
only about 1-1.5 wt %. To achieve a high contrast ratio, a
concentration of about 1.5 wt % of the Cu dye is needed. However,
due to its low solubility, the Cu dye inevitably will precipitate
out at low temperature (subzero) and as a result, the switching
performance of the display deteriorates dramatically. By mixing a
Si dye of the present invention with the Cu dye, a high contrast
ratio can be achieved without tradeoff in the low temperature
latitude. It also broadens the visible spectrum and increases the
color saturation in a monochrome display. The ratio of the Si dye
to the Cu dye in the mixture may range from 1/10 to 10/1,
preferably 1/5 to 5/1 and more preferably 1/3 to 3/1.
[0065] The charged pigment particles visually contrast with the
fluorinated solvent in which the particles are suspended. The
primary pigment particles may be organic or inorganic pigments,
such as TiO.sub.2, diarylide yellow, diarylide AAOT yellow, and
quinacridone, azo, rhodamine, perylene pigment series from Sun
Chemical, Hansa yellow G particles from Kanto Chemical and Carbon
Lampblack from Fisher. The pigment particles may be prepared by any
of the well-known methods including grinding, milling, attriting,
microfluidizing and ultrasonic techniques. For example, pigment
particles in the form of a fine powder are added to the suspending
solvent and the resulting mixture is ball milled or attrited for
several hours to break up the highly agglomerated dry pigment
powder into primary particles. Particle size of the pigment
particles is preferably in the range of 0.01-10 microns, more
preferably in the range of 0.05-3 microns. These particles should
have acceptable optical characteristics, should not be swollen or
softened by the dielectric solvent and should be chemically stable.
The resulting dispersion must also be stable against sedimentation,
creaming or flocculation under normal operating conditions.
[0066] In order for the display composition to achieve high hiding
power or light scattering efficiency, high dispersion stability,
low rate of sedimentation or creaming and high mobility even with a
high solid content and under a wide range of applied voltages, the
pigment particles are preferably microencapsulated or coated with a
polymer matrix of low specific gravity. Microencapsulation of the
pigment particles may be accomplished chemically or physically.
Typical microencapsulation processes include interfacial
polymerization/crosslin king, in-situ polymerization/crosslin king,
phase separation, simple or complex coacervation, electrostatic
coating, spray drying, fluidized bed coating and solvent
evaporation. Improved processes of making density-matched pigment
microcapsules of high mobility involving the use of reactive
protective colloids and charge controlling agents are disclosed in
U.S. Serial No. 60/345,936, filed on Jan. 3, 2002, U.S. Serial No.
60/345,934 filed on Jan. 3, 2002, U.S. Ser. No. 10/335,210 filed on
Dec. 31, 2002 and U.S. Ser. No. 10/335,051 filed on Dec. 31, 2002,
all of which are incorporated herein by reference.
[0067] The resulting display composition may then be filled into
the display cells and sealed.
[0068] V. Electrophoretic, Magnetophoretic or
Electromagnetophoretic Display of the Present Invention
[0069] The display cells may be the conventional partition type
cells (as disclosed in M. A. Hopper and V. Novotny, IEEE Trans.
Electr. Dev., Vol. ED 26, No. 8, pp.1148-1152 (1979)), the
microcapsule type cells (as disclosed in U.S. Pat. Nos. 5,961,804
and 5,930,026) and the display cells prepared from the microcup
technology as disclosed in co-pending applications, U.S. Ser. No.
09/518,488, filed on Mar. 3, 2000 (corresponding to WO 01/67170
published on Sep. 13, 2001), U.S. Ser. No. 09/759,212, filed on
Jan. 11, 2001 (corresponding to WO02/56097 published on Jul. 18,
2002), U.S. Ser. No. 09/606,654, filed on Jun. 28, 2000
(corresponding to WO 02/01281 published on Jan. 3, 2002) and U.S.
Ser. No. 09/784,972, filed on Feb. 15, 2001 (corresponding to
WO02/65215 published on Aug. 22, 2002), all of which are
incorporated herein by reference. The improved microcup-based
display comprises isolated cells formed from microcups of
well-defined shape, size and aspect ratio and filled with charged
particles dispersed in a dielectric solvent or solvent mixture,
preferably a halogenated solvent, particularly a fluorinated
solvent. The filled cells are individually sealed with a polymeric
sealing layer, preferably formed from a composition comprising a
material selected from a group consisting of thermoplastics,
thermosets and precursors thereof.
EXAMPLES
Preparation 1
Preparation of R.sub.f-amine Oligomers for Microencapsulation
[0070] 4
[0071] 17.8 Grams of Krytox.RTM. methyl ester (MW=.about.1780,
a=about 10, from DuPont) was dissolved in a mixture of 12 g of
1,1,2-trichlorotrifluoroethane (Aldrich) and 1.5 g of
.alpha.,.alpha.,.alpha.-trifluorotoluene (Aldrich). The resulting
solution was added drop by drop into a solution containing 7.3 g of
tris(2-aminoethyl)amine (MW=146, from Aldrich) in 25 g of
.alpha.,.alpha.,.alpha.-trifluorotoluene and 30 g of
1,1,2-trichlorotrifluoroethene, over 2 hours with stirring at room
temperature. The mixture was then stirred for another 8 hours to
allow the reaction to complete. The IR spectrum of the product
clearly indicated the disappearance of the C.dbd.O vibration for
the methyl ester at 1780 cm.sup.-1 and the appearance of the
C.dbd.O vibration for the amide product at 1695 cm.sup.-1. The
solvents were removed by rotary evaporation followed by vacuum
stripping at 100.degree. C. for 4-6 hours (1 Torr). The crude
product was then dissolved in 50 ml of PFS-2 solvent (low molecular
weight perfluoropolyether from Ausimont) and extracted three times
with 20 ml of ethyl acetate; then dried to yield 17 g of purified
product (R.sub.f-amine 1900) which showed excellent solubility in
HT200. R.sub.f-amine650 (a=about 3) was also synthesized according
to the same procedure
Preparation 2
Preparation of Density Matched TiO.sub.2 Microcapsules
[0072] 5.9 Grams of TiO.sub.2 R900 (DuPont) was added to a solution
consisting of 3.77 g of MEK, 4.31 g of N3400 aliphatic
polyisocyanate (Bayer AG) and 0.77 g of
1-[N,N-bis(2-hydroxyethyl)amino]-2-propanol (Aldrich). The
resulting slurry was homogenized for 1 minute at 5-10.degree. C.;
0.01 g of dibutyltin dilaurate (Aldrich) was added and homogenized
for an additional minute at 5-10.degree. C.; and finally a solution
containing 20 g of HT-200 and 0.47 g of R.sub.f-amine 1900 (from
Preparation 1) was added and homogenized again for 3 minutes at
room temperature.
[0073] The slurry prepared above was emulsified slowly at room
temperature by a homogenizer into a mixture of 31 g of HT-200 and
2.28 g of R.sub.f-amine650 (from Preparation 1). The resulting
microcapsule dispersion was kept stirring under low shear by a
mechanical stirrer at 35.degree. C. for 30 minutes and at
80.degree. C. for 3 hours to remove MEK and post cure the
microcapsules. The microcapsule dispersion showed a narrow particle
size distribution ranging from 0.5-3.5 microns. The microcapsules
were separated by centrifuge, rinsed with an excess of HT-200 and
finally re-dispersed in HT-200.
Example 1
Synthesis and Evaluation of Fluorinated Silicon Phthalocyanine
Compound (1)
[0074] As shown in Scheme 1 below, the 2 step, 1 pot procedure
involves conversion of a highly fluorinated ether alcohol
(Krytox.TM. from DuPont) to its sodium salt, followed by, without
isolation, reaction with silicon phthalocyanine dichloride
(Aldrich).
[0075] The Structure of Compound (1) 5 6
[0076] A mixture of KrytoX.TM. monofunctional alcohol (M.W. 1571,
6.51 g, 4.15 mmol, Du Pont), sodium lump (0.14 g, 6.09 mmol) and
anhydrous ether (20 mL) was refluxed for 23 hours under Ar
atmosphere. The resulting mixture was added to a suspension of
silicon phthalocyanine dichloride
[dichloro(29H,3H-phthalocyaninato)silicon, SiPcCl.sub.2] (1.00 g,
1.64 mmol, Aldrich), toluene (80 mL) and pyridine (20 mL), where
the toluene and pyridine each had been dried by distillation (-10
mL of distillate) via pipette (without adding unreacted sodium
pieces). The resulting mixture was distilled slowly over 24 hours
(.about.40 mL distillate) via a Dean-Stark trap for water removal.
The blue suspension obtained was mixed with Al.sub.2O.sub.3
(activity grade 1, neutral, 44 g, Fisher Scientific) and evaporated
to dryness by rotary evaporation (60.degree. C.) under pump vacuum
(.about.5 Torr). The resulting blue solid was added to an
extraction thimble and extracted with ether (300 mL, Fisher
Scientific)) by Soxhlet extraction for 21 hours. The resulting dark
blue extract was evaporated to dryness by rotary evaporation
(60.degree. C.) under pump vacuum (-5 Torr). A dark blue sticky
solid, Compound (1), was obtained (5.66 g, 92%).
[0077] An EPD fluid containing 2 wt % of Compound (1) and 6 wt %
solid of the TiO.sub.2 microcapsules (from Preparation 2) in HT-200
was prepared and filled between two ITO glass plates using PET
films (35 microns thick, from DuPont, Hopewell, Va.) as the
spacers. A contrast ratio of 11 was measured using a Spectrolino
GretagMacbeth.TM. at a switching voltage of 80 V.
Example 2
Synthesis and Evaluation of Fluorinated Silicon Phthalocyanine
Compound (2)
[0078] The Structure of Compound (2) 7 8
[0079] As shown in Scheme 2, a mixture of
(heptadecafluoro-1,1,2,2-tetrahy- drodecyl) trichlorosilane (1.30
mL, Gelest) and a suspension of SiPc(OH).sub.2 (0.51 g, 0.87 mmol,
Aldrich) in toluene (80 mL) and pyridine (20 mL), where the toluene
and pyridine each had been dried by distillation (.about.15 mL of
distillate), was refluxed for 14 hours.
1H,1H-Perfluoro-1-tetradecanol (6.21 g, 0.89 mmol, Lancaster) was
added to the resulting solution after cooling to room temperature
and the mixture was slowly distilled for 23 hours (.about.15 mL
distillate). The blue solution obtained was mixed with
Al.sub.2O.sub.3 (20 g, activity grade I, neutral, Fisher
Scientific) and evaporated to dryness by rotary evaporation
(60.degree. C.) under pump vacuum (.about.5 Torr). The resulting
blue solid was added into a thimble and was extracted with
PFS-2.TM. (150 mL, Ausimont) by Soxhlet extraction for 6 hours. The
resulting dark blue extract was evaporated to dryness by rotary
evaporation (60.degree. C.) under pump vacuum (.about.5 Torr). A
dark blue sticky solid, Compound (2), was obtained (3.44 g, yield
91%).
[0080] An EPD fluid containing 2 wt % of Compound (2) and 6 wt %
solid of the TiO.sub.2 microcapsules (from Preparation 2) in HT200
was prepared and evaluated as in Example 1. A contrast ratio of 15
was observed at a switching voltage of 80 V.
Example 3
Synthesis and Evaluation of Fluorinated Silicon Phthalocyanine
Compound (3)
[0081] The structure of Compound (3) 9 10
[0082] A. Synthesis of Bromosilane (A):
BrSi(CH.sub.2CH.sub.2CF.sub.2CF.su-
b.2CF.sub.2CF.sub.2CF.sub.2CF.sub.3).sub.3
[0083] This procedure was modified from the synthesis described in
J. Org. Chem., 1997, 62, 2917-2924. A mixture of magnesium turnings
(1.00 g, 40.9 mmol, Aldrich), 2 crystals of iodine (Fisher
Scientific) and dry ether (10.0 mL, Fisher Scientific) was refluxed
for 40 min, then cooled to room temperature.
1-Iodo-1H,1H,2H,2H-perfluorooctane (12.2 g, 25.6 mmol, Lancaster)
in a dry ether solution (50 mL, Fisher Scientific) was added
dropwise into the above mixture over 30 minutes. The mixture was
refluxed for 15 hours. Trichlorosilane (0.80 mL, 7.98 mmol,
Aldrich) was added into the resulting suspension after cooling and
the suspension was refluxed for another 21 hours. The suspension
obtained was filtered in order to remove unreacted magnesium
turning. The filtrate was combined with a saturated ammonium
chloride aqueous solution (30 mL) and the mixture was extracted
with PFS-2.TM. (3.times.20 mL, Ausimont). The extract was dried
over anhydrous sodium sulfate and evaporated to dryness by rotary
evaporation (60.degree. C.) under pump vacuum evaporated (.about.5
Torr). A yellow semisolid obtained was mixed with PFS-2.TM. 20 mL
and to this mixture bromine (0.5 mL, 9.76 mmol, Acros) was added
via a syringe. The resulting solution was stirred at room
temperature for 14 hours. The dark orange solution obtained was
washed with acetone (4.times.20 mL, Fisher Scientific) and
evaporated to dryness by rotary evaporation (60.degree. C.) under
pump vacuum (.about.5 Torr). 8.67 Grams of a yellow semisolid
product, Bromosilane (A), was obtained (95% yield based on
trichlorosilane).
[0084] B. The Synthesis of Compound (3)
[0085] As shown in Scheme 3, a mixture of Bromosilane (A) and a
suspension of SiPc(OH).sub.2 (1.50 g, 2.60 mmol, Aldrich), toluene
(150 mL, Fisher Scientific) and pyridine (15 mL, Fisher
Scientific), where the toluene and pyridine each had been dried by
distillation (.about.8 mL of distillate), was refluxed for 26
hours, evaporated to dryness by rotary evaporation (60.degree. C.)
under pump vacuum (.about.5 Torr) and mixed with PFS-2TM (50 mL,
Ausimont) and Al.sub.2O.sub.3 III (Neutral, 20 g, Fisher
Scientific). The resulting suspension was filtered and the residue
was extracted with PFS-2 via a Soxhlet Extractor. The filtrate and
extract combined was filtered and the filtrate obtained was
evaporated to dryness by rotary evaporation (60.degree. C.) under
pump vacuum (1 Torr). A blue, waxy product, Compound (3), was
obtained (2.44 gm, 35% yield based on SiPc(OH).sub.2).
[0086] An EPD fluid containing 5 wt % of Compound (3) and 6 wt %
solid of the TiO.sub.2 microcapsules (from Preparation 2) in HT-200
was prepared and evaluated as in Example 1. Contrast ratios of
27-32 were observed at switching voltages of 10-40 V.
Example 4
Synthesis and Evaluation of Fluorinated Silicon Phthalocyanine
Compound (4)
[0087] The Structure of Compound (4) 11 12
[0088] As shown in Scheme 4, a mixture of sodium dithionite (0.80
g, 4.60 mmol, Fluka) and sodium bicarbonate (0.40 g, 4.76 mmol,
Aldrich) was added to a suspension of silicon phthalocyanine
bis(trihexylsilyloxide) (0.36 g, 0.30 mmol, Aldrich), cetyl
trimethylammonium bromide (0.20 g, Aldrich), 1-iodo-perfluorooctane
(4.0 g, 7.33 mmole, Lancaster), CH.sub.2Cl.sub.2 (20 mL, HPLC
grade, Fisher Scientific) and distilled water (20 mL). The
resulting suspension was vigorously stirred at room temperature for
14 hours. Distilled water (20 mL), acetone (10 mL, Fisher
Scientific) and PFS-2.TM. (10 mL, Ausimont) were added into the
mixture obtained. The CH.sub.2Cl.sub.2 and PFS-2.TM. layer was
separated and washed with water (3.times.20 mL). A concentrated HCl
solution (10 mL, Fisher Scientific) and PFS-2.TM. (100 mL) were
added and the resulting mixture was stirred vigorously at room
temperature for 16 hours. The PFS-2.TM. layer was separated, washed
with 20 mL of distilled water three times, dried over anhydrous
Na.sub.2SO.sub.4 and evaporated to dryness by rotary evaporation
(60.degree. C.) under pump vacuum (.about.5 Torr). The resulting
dark blue oil was chromatographed (Al.sub.2O.sub.3 .mu.l, neutral,
Fisher scientific) on a column of dimensions 1.5.times.1 5 cm,
eluted with PFS-2.TM. (Ausimont) first and then with ether (HPLC
grade, Fisher Scientific). A dark blue product, Compound (4), was
obtained (0.062 gm, 9% yield).
[0089] An EPD fluid containing 3 wt % of Compound (4) and 6 wt %
solid of the TiO.sub.2 microcapsules (from Preparation 2) in HT200
was prepared and evaluated as in Example 1. Contrast ratios of 14,
18, and 19 were observed at switching voltages of 10, 20, and 40 V
respectively.
Example 5
Synthesis and Evaluation of Fluorinated Silicon Phthalocyanine
Compound (5)
[0090] The Structure of Compound (5) 13 14
[0091] A. The Synthesis of
SiPc(OSi(CH.sub.3).sub.2(CH.sub.2).sub.2(CF.sub-
.2).sub.7CF.sub.3).sub.2
[0092] As shown in Scheme 5, a mixture of
(heptadecafluoro-1,1,2,2-tetrahy- drodecyl)dimethylchlorosilane
(2.50 g, 4.63 mmol, Gelest) and a suspension of SiPc(OH).sub.2
(1.00 g, 1.74 mmol, Aldrich) and pyridine (140 mL, Fisher
Scientific), which had been dried by distillation (.about.10 mL of
distillate), was slowly distilled for 5 hours (.about.55 mL
distillate). The resulting dark blue solution was evaporated to
dryness by rotary evaporation (60.degree. C.) under pump vacuum (1
Torr). The solid obtained was washed with an EtOH-H.sub.2O mixture
(1:1, 50 mL) and removed by filtration, dried (60.degree. C., 60
Torr), dissolved in CH.sub.2Cl.sub.2 (120 mL) and filtered. The
filtrate was evaporated to dryness by rotary evaporation
(60.degree. C.) under pump vacuum (1 Torr). Phthalocyanine (A), a
blue solid (2.26 g, 82% based on SiPc(OH).sub.2), was obtained.
[0093] B. The Synthesis of Compound (5)
[0094] A mixture of sodium dithionite (1.60 g, 9.19 mmol, Fluka)
and sodium bicarbonate (0.80 g, 9.52 mmol, Aldrich) was added into
a suspension containing the silicon phthalocyanine and
SiPc(OSi(CH.sub.3).sub.2(CH.sub.2).sub.2(CF.sub.2).sub.7CF.sub.3).sub.2
(2.26 g, 1.43 mmol) obtained from the procedure 5.A above. To the
mixture, 1-iodoperfluorooctane (4.0 g, 7.33 mmol, Lancaster),
cetyltrimethylammonium bromide (0.20 g, 0.55 mmol, Aldrich),
CH.sub.2Cl.sub.2 (50 mL) and water (50 mL) were added while
stirring vigorously at room temperature. The mixture obtained was
kept stirring at room temperature for 18 hours, and then to which
water (20 mL) and PFS-2.TM. (40 mL) were added. The lower organic
layer was separated and evaporated to dryness by rotary evaporation
(60.degree. C.) under pump vacuum (1 Torr). The dark blue oil
obtained was chromatographed using PFS-2.TM. as the eluent through
a column (1.times.10 cm) packed with Al.sub.2O.sub.3 III (neutral,
Fisher Scientific). The fractions with the blue product were
collected and evaporated to dryness by rotary evaporation
(60.degree. C.) under vacuum (.about.5 Torr). Phthalocyanine (A), a
blue solid, Compound (5), was obtained (1.41 gm, 30% yield).
[0095] An EPD fluid containing 1.8 wt % of Compound (5) and 6 wt %
solid of the TiO.sub.2 microcapsules (from Preparation 2) in HT-200
was prepared and evaluated as in Example 1. Contrast ratios of 26,
43, 71, and 163 were observed at switching voltages of 5, 10, 20,
and 40V, respectively.
Example 6
Comparative Example
[0096] The Structure of Compound (6) 15 16
[0097] A fluorinated copper phthalocyanine dye, Compound (6), was
prepared according to U.S. Pat. No. 3,281,426 (Scheme 6). A mixture
of copper phthalocyanine (41.0 g, 71.2 mmole, Aldrich) and
1-iodoperfluorooctane (370 g, 678 mmole, SynQuest) was added into a
1-gallon pressure reactor (Parr Instrument Co.) with a glass liner.
The reactor was vacuum sealed at 1 Torr and heated at 375.degree.
C. for 3 days. The crude product obtained was mixed with 200 g of
Celite (Fisher Scientific) and extracted with 4 L of PFS-2.TM. in a
Soxhlet extractor for 5 days. The dark blue solution obtained was
washed with 4L of acetone 3 times and evaporated to dryness by
rotary evaporation (60.degree. C.) under vacuum (.about.5 Torr). A
dark blue solid, Compound (6), was obtained (106 g, 66% yield).
[0098] The maximum solubility of the fluorinated copper
phthalocyanine, Compound (6), is about 1.5 wt % in HT-200. An EPD
fluid containing 1.5 wt % of Compound (6) and 6 wt % solid of the
TiO.sub.2 microcapsules (from Preparation 2) in HT-200 was prepared
and evaluated as in Example 1. Contrast ratios of 15-17 were
observed at switching voltages of 10-40V.
Example 7
Comparative Example
[0099] 1.0 wt % of a fluorinated copper phthalocyanine blue dye,
FC3275 (from 3M Co., MN), was used to replace the 1.5 wt % of
Compound (6) in the EPD fluid of Example 6. The maximum solubility
of FC3275 in HT-200 was about 1 wt %. Contrast ratios of 6-16 were
observed at switching voltages of 40-80V.
[0100] As can be seen from the examples, the fluorinated Si
phthalocyanine dyes of the present invention showed significant
improvement over the fluorinated copper phthalocyanines in both
solubility and contrast ratio for EPD applications. Moreover, the
dyes, Compounds (1)-(5), also showed acceptable thermal and UV
stability for outdoor EPD applications.
[0101] While the present invention has been described with
reference to the specific embodiments thereof, it should be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted without departing from the
true spirit and scope of the invention. In addition, many
modifications may be made to adapt a particular situation,
materials, compositions, processes, process step or steps, to the
objective, spirit and scope of the present invention. All such
modifications are intended to be within the scope of the claims
appended hereto.
* * * * *