U.S. patent application number 14/371838 was filed with the patent office on 2014-12-11 for aqueous polyimide precursor solution composition and method for producing aqueous polyimide precursor solution.
The applicant listed for this patent is Ube Industries, Ltd.. Invention is credited to Kensuke Hiroshige, Takeshige Nakayama, Tomonori Nakayama, Susumu Takasaki.
Application Number | 20140363687 14/371838 |
Document ID | / |
Family ID | 48781552 |
Filed Date | 2014-12-11 |
United States Patent
Application |
20140363687 |
Kind Code |
A1 |
Nakayama; Takeshige ; et
al. |
December 11, 2014 |
AQUEOUS POLYIMIDE PRECURSOR SOLUTION COMPOSITION AND METHOD FOR
PRODUCING AQUEOUS POLYIMIDE PRECURSOR SOLUTION
Abstract
An aqueous polyimide precursor solution composition in which a
polyamic acid which is obtained by reacting a tetracarboxylic acid
component and a diamine component is dissolved in an aqueous
solvent together with an imidazole in an amount of 1.6 moles or
more per mole of the tetracarboxylic acid component of the polyamic
acid.
Inventors: |
Nakayama; Takeshige;
(Ube-shi, JP) ; Takasaki; Susumu; (Ube-shi,
JP) ; Nakayama; Tomonori; (Ube-shi, JP) ;
Hiroshige; Kensuke; (Ube-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ube Industries, Ltd. |
Ube-shi |
|
JP |
|
|
Family ID: |
48781552 |
Appl. No.: |
14/371838 |
Filed: |
January 10, 2013 |
PCT Filed: |
January 10, 2013 |
PCT NO: |
PCT/JP2013/050324 |
371 Date: |
July 11, 2014 |
Current U.S.
Class: |
428/473.5 ;
264/241; 525/419 |
Current CPC
Class: |
C08G 73/10 20130101;
C08K 5/3445 20130101; B29K 2105/0073 20130101; B29L 2031/3475
20130101; C08J 2379/08 20130101; B29C 39/38 20130101; B29K 2079/08
20130101; C08L 79/08 20130101; C08J 5/18 20130101; B29C 39/006
20130101; B29K 2105/0002 20130101; Y10T 428/31721 20150401; C08K
5/3445 20130101; C08L 79/08 20130101 |
Class at
Publication: |
428/473.5 ;
525/419; 264/241 |
International
Class: |
C08J 5/18 20060101
C08J005/18; B29C 39/00 20060101 B29C039/00; B29C 39/38 20060101
B29C039/38; C08G 73/10 20060101 C08G073/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 13, 2012 |
JP |
2012-005694 |
Claims
1. An aqueous polyimide precursor solution composition, wherein a
polyamic acid, which is formed by the reaction of a tetracarboxylic
acid component and a diamine component, and consists of a repeating
unit represented by the following formula (1), is dissolved in an
aqueous solvent together with an imidazole in an amount of 1.6 mole
or more per mole of the tetracarboxylic acid component of the
polyamic acid. ##STR00006## wherein A represents at least one
selected from the group consisting of a tetravalent group of an
aromatic tetracarboxylic acid containing no fluorine group, from
which carboxyl groups have been removed, a tetravalent group of an
aliphatic tetracarboxylic acid, from which carboxyl groups have
been removed, and a tetravalent group of an aromatic
tetracarboxylic acid containing a fluorine group, from which
carboxyl groups have been removed, and B represents at least one
selected from the group consisting of a divalent group of an
aromatic diamine containing no fluorine group and having a
solubility in water at 25.degree. C. of 0.1 g/L or more, from which
amino groups have been removed, a divalent group of an aliphatic
diamine having a molecular weight of 500 or less, from which amino
groups have been removed, and a divalent group of an aromatic
diamine containing a fluorine group, from which amino groups have
been removed, with the proviso that not less than 50 mol % of A is
a tetravalent group of an aliphatic tetracarboxylic acid, from
which carboxyl groups have been removed, and/or a tetravalent group
of an aromatic tetracarboxylic acid containing a fluorine group,
from which carboxyl groups have been removed, and not more than 50
mol %, including 0 mol %, of A is a tetravalent group of an
aromatic tetracarboxylic acid containing no fluorine group, from
which carboxyl groups have been removed, and/or not less than 50
mol % of B is a divalent group of an aliphatic diamine having a
molecular weight of 500 or less, from which amino groups have been
removed, and/or a divalent group of an aromatic diamine containing
a fluorine group, from which amino groups have been removed, and
not more than 50 mol %, including 0 mol %, of B is a divalent group
of an aromatic diamine containing no fluorine group and having a
solubility in water at 25.degree. C. of 0.1 g/L or more, from which
amino groups have been removed.
2. The aqueous polyimide precursor solution composition of claim 1,
wherein the imidazole is selected from the group consisting of
1,2-dimethylimidazole, 2-ethyl-4-methylimidazole,
4-ethyl-2-methylimidazole, and 1-methyl-4-ethylimidazole.
3. The aqueous polyimide precursor solution of claim 1, wherein the
aqueous polyimide precursor solution composition has an organic
solvent content of less than 5 wt %.
4. The aqueous polyimide precursor solution composition of claim 3,
wherein the aqueous polyimide precursor solution composition
contains substantially no organic solvent.
5. A polyimide produced by heating the aqueous polyimide precursor
solution composition of claim 1.
6. The polyimide of claim 5, wherein the polyimide has a light
transmittance at 400 nm of 60% or more when the polyimide is formed
into a film having a thickness of 10 .mu.m.
7. The polyimide of claim 5, wherein the polyimide has a total
light transmittance of 80% or more when the polyimide is formed
into a film having a thickness of 10 .mu.m.
8. A polyimide film obtained from the aqueous polyimide precursor
solution composition of claim 1, wherein the polyimide film has a
light transmittance at 400 nm of 60% or more in terms of 10 .mu.m
of film thickness.
9. A polyimide film obtained from the aqueous polyimide precursor
solution composition of claim 1, wherein the polyimide film has a
total light transmittance of 80% or more in terms of 10 .mu.m of
film thickness.
10. A method for producing an aqueous polyimide precursor solution
composition, comprising reacting a tetracarboxylic acid component,
which comprises an aliphatic tetracarboxylic dianhydride and/or an
aromatic tetracarboxylic dianhydride containing a fluorine group in
an amount of not less than 50 mol % and comprises an aromatic
tetracarboxylic dianhydride containing no fluorine group in an
amount of not more than 50 mol %, or alternatively, does not
comprise an aromatic tetracarboxylic dianhydride containing no
fluorine group, and a diamine component, which comprises an
aliphatic diamine having a molecular weight of 500 or less and/or
an aromatic diamine containing a fluorine group in an amount of not
less than 50 mol % and comprises an aromatic diamine containing no
fluorine group and having a solubility in water at 25.degree. C. of
0.1 g/L or more in an amount of not more than 50 mol %, or
alternatively, does not comprise an aromatic diamine containing no
fluorine group and having a solubility in water at 25.degree. C. of
0.1 g/L or more, in the presence of an imidazole using water as a
reaction solvent to provide an aqueous polyimide precursor solution
composition.
11. The method for producing an aqueous polyimide precursor
solution composition of claim 10, wherein the amount of the
imidazole used is 1.6 mole or more per mole of the tetracarboxylic
dianhydride.
12. (canceled)
13. (canceled)
14. An electrical device, an electronic device, an optical device,
a display device, a touch panel, a solar battery, or an LED
lighting device comprising the polyimide of claim 5.
15. A polyimide precursor resin composition for flexible device
substrates, wherein a polyamic acid, which is formed by the
reaction of a tetracarboxylic acid component and a diamine
component, and consists of a repeating unit represented by the
following formula (1), is dissolved in an aqueous solvent together
with an imidazole in an amount of 1.6 mole or more per mole of the
tetracarboxylic acid component of the polyamic acid. ##STR00007##
wherein A represents at least one selected from the group
consisting of a tetravalent group of an aromatic tetracarboxylic
acid containing no fluorine group, from which carboxyl groups have
been removed, a tetravalent group of an aliphatic tetracarboxylic
acid, from which carboxyl groups have been removed, and a
tetravalent group of an aromatic tetracarboxylic acid containing a
fluorine group, from which carboxyl groups have been removed, and B
represents at least one selected from the group consisting of a
divalent group of an aromatic diamine containing no fluorine group
and having a solubility in water at 25.degree. C. of 0.1 g/L or
more, from which amino groups have been removed, a divalent group
of an aliphatic diamine having a molecular weight of 500 or less,
from which amino groups have been removed, and a divalent group of
an aromatic diamine containing a fluorine group, from which amino
groups have been removed, with the proviso that not less than 50
mol % of A is a tetravalent group of an aliphatic tetracarboxylic
acid, from which carboxyl groups have been removed, and/or a
tetravalent group of an aromatic tetracarboxylic acid containing a
fluorine group, from which carboxyl groups have been removed, and
not more than 50 mol %, including 0 mol %, of A is a tetravalent
group of an aromatic tetracarboxylic acid containing no fluorine
group, from which carboxyl groups have been removed, and/or not
less than 50 mol % of B is a divalent group of an aliphatic diamine
having a molecular weight of 500 or less, from which amino groups
have been removed, and/or a divalent group of an aromatic diamine
containing a fluorine group, from which amino groups have been
removed, and not more than 50 mol %, including 0 mol %, of B is a
divalent group of an aromatic diamine containing no fluorine group
and having a solubility in water at 25.degree. C. of 0.1 g/L or
more, from which amino groups have been removed.
16. A method for producing a flexible device which is a display
device or a light-receiving device, comprising steps of: applying
the polyimide precursor resin composition for flexible device
substrates of claim 15 onto a carrier substrate, and then heating
the composition to form a solid polyimide resin film; forming a
circuit on the polyimide resin film; and separating the polyimide
resin film on which the circuit is formed from the carrier
substrate.
17. A flexible device produced by the method for producing a
flexible device of claim 16, wherein the flexible device is a
display device or a light-receiving device.
Description
TECHNICAL FIELD
[0001] The present invention relates to an aqueous polyimide
precursor solution composition and a method for easily producing an
aqueous polyimide precursor solution composition. The aqueous
polyimide precursor solution composition is preferred because of
having high environmental acceptability as compared with a
polyimide precursor solution composition comprising an organic
solvent. The production method of the present invention does not
require any solvent other than water, and therefore it may provide
an aqueous polyimide precursor solution composition having a lower
content of organic solvent than the conventional compositions, and
may provide an aqueous polyimide precursor solution composition
containing an aqueous solvent and containing no organic solvent,
which has higher environmental acceptability. In addition, a
polyimide may be suitably obtained from the aqueous polyimide
precursor solution composition. A polyimide obtained from a
specific aqueous polyimide precursor solution composition of the
present invention, in particular, has excellent properties such as
high transparency, flexibility, heat resistance, electrical
properties, and solvent resistance.
[0002] The present invention also relates to an aqueous polyimide
precursor solution composition for a flexible device substrate, for
example, an aqueous polyimide precursor solution composition for a
substrate of a display device such as a liquid crystal display, an
organic EL display and an electronic paper, and a light-receiving
device such as a light-receiving element of a thin-film solar
battery.
BACKGROUND ART
[0003] A polyimide obtained from a tetracarboxylic dianhydride and
a diamine has excellent properties such as heat resistance,
mechanical strength, electrical properties, and solvent resistance,
and therefore is widely used in the electrical/electronics
industrial field, and the like. Because polyimides have poor
solubility in organic solvents, however, polyimides are generally
prepared by applying a solution composition in which a polyamic
acid as a polyimide precursor is dissolved in an organic solvent,
for example, onto a substrate surface, and then heating the
solution composition at a high temperature to effect
dehydration/ring closure (imidization). The polyamic acid solution
composition to produce a polyimide contains an organic solvent and
must be subjected to heat treatment at a high temperature, and
therefore the polyamic acid solution composition is not necessarily
environmentally friendly and in some cases, its application is
limited.
[0004] Meanwhile, with the coming of an advanced information
society, the developments of optical materials such as an optical
fiber and an optical waveguide in the field of optical
communications, and optical materials such as a liquid crystal
oriented film and a protective film for a color-filter in the field
of display devices has recently advanced. In the field of display
devices, in particular, a plastic substrate which is light-weight
and excellent in flexibility has been studied as an alternative to
a glass substrate, and the development of a display which is
capable of being folded and rolled has been intensively conducted.
Accordingly, there is need for a higher-performance optical
material which may be used for such purposes.
[0005] Generally, polyimides are intrinsically
yellowish-brown-colored due to intramolecular conjugation and
formation of charge-transfer complexes. As a solution to this
problem, a method of developing transparency, for example, by
introducing fluorine into the molecule, imparting flexibility to
the main chain, introducing a bulky side chain into the molecule,
or the like to suppress the formation of charge-transfer complexes
is proposed (Non Patent Literature 1). Methods of developing
transparency by using semi-alicyclic or wholly-alicyclic polyimide
resins which do not form charge-transfer complexes in principle are
also proposed (Patent Literature 1, Patent Literature 2, Patent
Literature 3, Non Patent Literature 2). Among them, the use of
alicyclic tetracarboxylic dianhydride and/or alicyclic diamine as
the monomer component, and the introduction of fluorine into the
molecule are particularly effective methods for providing
transparent polyimide.
[0006] As for a water-soluble polyimide precursor, Patent
Literature 4, for example, proposes a process for producing an
aqueous polyamide acid salt solution composition, comprising
[0007] polymerizing a tetracarboxylic dianhydride and a diamine in
an organic solvent, to provide a polyamide acid;
[0008] optionally hydrolyzing the polyamide acid, as necessary;
[0009] pouring the resulting varnish into water, to pulverize the
polyamide acid and to extract and remove a reaction solvent
contained in the polyamide acid;
[0010] drying the polyamide acid; and
[0011] reacting the polyamide acid in water with a certain amine
compound such as 2-methylamino diethanol to form a water-soluble
polyamide acid salt. However, it is difficult to form a high
molecular weight polymer from this aqueous polyamide acid salt
solution composition (polyimide precursor composition) and it is
also desirable to further improve the properties of the polyimide
obtained.
[0012] Patent Literature 5 proposes a water-soluble polyimide
precursor prepared by reacting a polyamic acid (polyimide
precursor), which is prepared by reacting a tetracarboxylic acid
component with an aromatic diamine component in an organic solvent,
with 1,2-dimethylimidazole and/or 1-methyl-2-ethylimidazole, and
then separating the water-soluble polyimide precursor from the
reaction mixture. The water-soluble polyimide precursors prepared
in Examples of Patent Literature 5, however, were ones from which
only amorphous aromatic polyimides could be obtained. Although a
polyimide which is obtained from the water-soluble polyimide
precursor prepared in Patent Literature 5 is amorphous and
thermal-fusion bondable, and is suitably used as a binder for a
woven or nonwoven fabric made of organic or inorganic fibers, there
is room for improvement in the properties of the polyimide in some
applications. Additionally, the aqueous polyimide precursor
solution composition is prepared by a process, comprising
[0013] preparing a water-soluble polyimide precursor in an organic
solvent;
[0014] separating the water-soluble polyimide precursor therefrom;
and
[0015] dissolving the separated water-soluble polyimide precursor
in an aqueous solvent.
Thus, extremely complicated operations are needed. Moreover, an
organic solvent cannot be completely removed from a water-soluble
polyimide precursor prepared in the organic solvent. (If the
water-soluble polyimide precursor is heated so as to completely
remove the organic solvent, imidization occurs, and therefore the
polyimide precursor loses solubility in water.) For this reason,
the aqueous polyimide precursor solution composition obtained will
inevitably contain an organic solvent.
[0016] In addition, Patent Literature 6 proposes a method for
producing a flexible device substrate, using a polyimide precursor
resin composition which comprises an organic solvent, specifically,
N-methyl-2-pyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, or the like as a solvent. In the meantime,
from the point of view of environmental acceptability, there is a
need for a composition comprising an aqueous solvent, as described
above.
CITATION LIST
Patent Literature
[0017] Patent Literature 1: JP-A-2002-348374 [0018] Patent
Literature 2: JP-A-2005-15629 [0019] Patent Literature 3:
JP-A-2002-161136 [0020] Patent Literature 4: JP-A-H08-59832 [0021]
Patent Literature 5: JP-A-2002-226582 [0022] Patent Literature 6:
JP-A-2010-202729
Non Patent Literature
[0022] [0023] Non Patent Literature 1: Polymer, 47, 2337 (2006)
[0024] Non Patent Literature 2: M. Hasegawa, High Perform. Polym.
13, S93-S106 (2001)
SUMMARY OF INVENTION
Problems to be Solved by the Invention
[0025] The first objective of the present invention is to provide
an aqueous polyimide precursor solution composition which comprises
an aqueous solvent and has good environmental acceptability, and
may provide a polyimide having high transparency, and having
excellent properties such as flexibility, heat resistance,
electrical properties, and solvent resistance, and preferably
comprises a solvent containing no organic solvent other than water.
Another objective of the present invention is to provide a method
for easily producing the aqueous polyimide precursor solution
composition without the need for a solvent other than water.
[0026] The second objective of the present invention is to provide
a polyimide precursor resin composition for flexible device
substrates which comprises an aqueous solvent and has good
environmental acceptability, and may provide a polyimide substrate
for flexible device having high transparency, and having excellent
properties such as flexibility, heat resistance, electrical
properties, and solvent resistance, and being suitably usable as a
substrate for flexible device as a display device such as
substrates for a liquid crystal display, an organic EL display and
an electronic paper, a substrate for flexible device as a
light-receiving device such as a substrate for a thin-film solar
battery, and the like, and preferably comprises a solvent
containing no organic solvent other than water.
Means for Solving the Problems
[0027] The present invention relates to the following items.
[0028] [1] An aqueous polyimide precursor solution composition,
wherein
[0029] a polyamic acid, which is formed by the reaction of a
tetracarboxylic acid component and a diamine component, and
consists of a repeating unit represented by the following formula
(1), is dissolved in an aqueous solvent together with an imidazole
in an amount of 1.6 mole or more per mole of the tetracarboxylic
acid component of the polyamic acid.
##STR00001##
wherein
[0030] A represents at least one selected from the group consisting
of a tetravalent group of an aromatic tetracarboxylic acid
containing no fluorine group, from which carboxyl groups have been
removed, a tetravalent group of an aliphatic tetracarboxylic acid,
from which carboxyl groups have been removed, and a tetravalent
group of an aromatic tetracarboxylic acid containing a fluorine
group, from which carboxyl groups have been removed, and
[0031] B represents at least one selected from the group consisting
of a divalent group of an aromatic diamine containing no fluorine
group and having a solubility in water at 25.degree. C. of 0.1 g/L
or more, from which amino groups have been removed, a divalent
group of an aliphatic diamine having a molecular weight of 500 or
less, from which amino groups have been removed, and a divalent
group of an aromatic diamine containing a fluorine group, from
which amino groups have been removed,
with the proviso that
[0032] not less than 50 mol % of A is a tetravalent group of an
aliphatic tetracarboxylic acid, from which carboxyl groups have
been removed, and/or a tetravalent group of an aromatic
tetracarboxylic acid containing a fluorine group, from which
carboxyl groups have been removed, and not more than 50 mol %,
including 0 mol %, of A is a tetravalent group of an aromatic
tetracarboxylic acid containing no fluorine group, from which
carboxyl groups have been removed, and/or
[0033] not less than 50 mol % of B is a divalent group of an
aliphatic diamine having a molecular weight of 500 or less, from
which amino groups have been removed, and/or a divalent group of an
aromatic diamine containing a fluorine group, from which amino
groups have been removed, and not more than 50 mol %, including 0
mol %, of B is a divalent group of an aromatic diamine containing
no fluorine group and having a solubility in water at 25.degree. C.
of 0.1 g/L or more, from which amino groups have been removed.
[0034] [2] The aqueous polyimide precursor solution composition as
described in [1], wherein the imidazole is selected from the group
consisting of 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole,
4-ethyl-2-methylimidazole, and 1-methyl-4-ethylimidazole.
[0035] [3] The aqueous polyimide precursor solution composition as
described in any one of [1] to [2], wherein the aqueous polyimide
precursor solution composition has an organic solvent content of
less than 5 wt %.
[0036] [4] The aqueous polyimide precursor solution composition as
described in [3], wherein the aqueous polyimide precursor solution
composition contains substantially no organic solvent.
[0037] [5] A polyimide produced by heating the aqueous polyimide
precursor solution composition as described in any one of [1] to
[4].
[0038] [6] The polyimide as described in [5], wherein the polyimide
has a light transmittance at 400 nm of 60% or more when the
polyimide is formed into a film having a thickness of 10 .mu.m.
[0039] [7] The polyimide as described in [5], wherein the polyimide
has a total light transmittance of 80% or more when the polyimide
is formed into a film having a thickness of 10 .mu.m.
[0040] [8] A polyimide film obtained from the aqueous polyimide
precursor solution composition as described in any one of [1] to
[4], wherein the polyimide film has a light transmittance at 400 nm
of 60% or more in terms of 10 .mu.m of film thickness.
[0041] [9] A polyimide film obtained from the aqueous polyimide
precursor solution composition as described in any one of [1] to
[4], wherein the polyimide film has a total light transmittance of
80% or more in terms of 10 .mu.m of film thickness.
[0042] [10] A method for producing an aqueous polyimide precursor
solution composition, comprising
[0043] reacting a tetracarboxylic acid component, which comprises
an aliphatic tetracarboxylic dianhydride and/or an aromatic
tetracarboxylic dianhydride containing a fluorine group in an
amount of not less than 50 mol % and comprises an aromatic
tetracarboxylic dianhydride containing no fluorine group in an
amount of not more than 50 mol %, or alternatively, does not
comprise an aromatic tetracarboxylic dianhydride containing no
fluorine group, and a diamine component, which comprises an
aliphatic diamine having a molecular weight of 500 or less and/or
an aromatic diamine containing a fluorine group in an amount of not
less than 50 mol % and comprises an aromatic diamine containing no
fluorine group and having a solubility in water at 25.degree. C. of
0.1 g/L or more in an amount of not more than 50 mol %, or
alternatively, does not comprise an aromatic diamine containing no
fluorine group and having a solubility in water at 25.degree. C. of
0.1 g/L or more, in the presence of an imidazole using water as a
reaction solvent to provide an aqueous polyimide precursor solution
composition.
[0044] [11] The method for producing an aqueous polyimide precursor
solution composition as described in [10], wherein the amount of
the imidazole used is 1.6 mole or more per mole of the
tetracarboxylic dianhydride.
[0045] [12] Use of the aqueous polyimide precursor solution
composition as described in any one of [1] to [4] for the
production of an electrical device, an electronic device, an
optical device, a display device, a touch panel, a solar battery,
or an LED lighting device.
[0046] [13] Use of the polyimide as described in any one of [5] to
[7] or the polyimide film as described in any one of [8] to [9] as
a substrate, or a protective film for an electrical device, an
electronic device, an optical device, a display device, a touch
panel, a solar battery, or an LED lighting device.
[0047] [14] An electrical device, an electronic device, an optical
device, a display device, a touch panel, a solar battery, or an LED
lighting device comprising the polyimide as described in any one of
[5] to [7] or the polyimide film as described in any one of [8] to
[9].
[0048] [15] A polyimide precursor resin composition for flexible
device substrates, wherein
[0049] a polyamic acid, which is formed by the reaction of a
tetracarboxylic acid component and a diamine component, and
consists of a repeating unit represented by the following formula
(1), is dissolved in an aqueous solvent together with an imidazole
in an amount of 1.6 mole or more per mole of the tetracarboxylic
acid component of the polyamic acid.
##STR00002##
wherein
[0050] A represents at least one selected from the group consisting
of a tetravalent group of an aromatic tetracarboxylic acid
containing no fluorine group, from which carboxyl groups have been
removed, a tetravalent group of an aliphatic tetracarboxylic acid,
from which carboxyl groups have been removed, and a tetravalent
group of an aromatic tetracarboxylic acid containing a fluorine
group, from which carboxyl groups have been removed, and
[0051] B represents at least one selected from the group consisting
of a divalent group of an aromatic diamine containing no fluorine
group and having a solubility in water at 25.degree. C. of 0.1 g/L
or more, from which amino groups have been removed, a divalent
group of an aliphatic diamine having a molecular weight of 500 or
less, from which amino groups have been removed, and a divalent
group of an aromatic diamine containing a fluorine group, from
which amino groups have been removed,
with the proviso that
[0052] not less than 50 mol % of A is a tetravalent group of an
aliphatic tetracarboxylic acid, from which carboxyl groups have
been removed, and/or a tetravalent group of an aromatic
tetracarboxylic acid containing a fluorine group, from which
carboxyl groups have been removed, and not more than 50 mol %,
including 0 mol %, of A is a tetravalent group of an aromatic
tetracarboxylic acid containing no fluorine group, from which
carboxyl groups have been removed, and/or
[0053] not less than 50 mol % of B is a divalent group of an
aliphatic diamine having a molecular weight of 500 or less, from
which amino groups have been removed, and/or a divalent group of an
aromatic diamine containing a fluorine group, from which amino
groups have been removed, and not more than 50 mol %, including 0
mol %, of B is a divalent group of an aromatic diamine containing
no fluorine group and having a solubility in water at 25.degree. C.
of 0.1 g/L or more, from which amino groups have been removed.
[0054] [16] A method for producing a flexible device which is a
display device or a light-receiving device, comprising steps
of;
[0055] applying a polyimide precursor resin composition for
flexible device substrates as described in [15] onto a carrier
substrate, and then heating the composition to form a solid
polyimide resin film;
[0056] forming a circuit on the polyimide resin film; and
[0057] separating the polyimide resin film on which the circuit is
formed from the carrier substrate.
[0058] [17] A flexible device produced by a method for producing a
flexible device as described in [16], wherein the flexible device
is a display device or a light-receiving device.
Effect of the Invention
[0059] According to the present invention, there may be provided an
aqueous polyimide precursor solution composition which comprises an
aqueous solvent and has good environmental acceptability, and may
provide a polyimide having high transparency, and having excellent
properties such as flexibility, heat resistance, electrical
properties, and solvent resistance, and preferably comprises a
solvent containing no organic solvent other than water. In
addition, according to the present invention, there may be provided
an aqueous polyimide precursor solution composition which comprises
a polyimide precursor (polyamic acid) having a high molecular
weight. A polyimide having excellent properties may be obtained
from the aqueous polyimide precursor solution composition. There
have been no aqueous polyimide precursor solution compositions from
which polyimides having such excellent properties can be obtained.
Additionally, a polyimide having particularly high transparency may
be obtained when using an aliphatic tetracarboxylic dianhydride
and/or an aliphatic diamine having a molecular weight of 500 or
less, or alternatively, when using an aromatic tetracarboxylic
dianhydride containing a fluorine group (fluorine atom) and/or an
aromatic diamine containing a fluorine group (fluorine atom).
[0060] The polyimide which is obtained from the aqueous solution
composition of the polyimide precursor having a specific
composition and prepared according to the present invention, in
particular, has high transparency, and has excellent properties
such as flexibility, heat resistance, electrical properties, and
solvent resistance. Accordingly, the polyimide may be suitably used
for an electrical device, an electronic device, and an optical
device, and may be suitably used, for example, as a substrate, or a
protective film for a display device such as a liquid crystal
display, an EL display and an electronic paper, a touch panel, a
solar battery, or an LED lighting device, or the like. The
polyimide may be particularly suitably used as a substrate of a
flexible device, for example, a display device such as a liquid
crystal display, an organic EL display and an electronic paper, and
a light-receiving device such as a light-receiving element of a
thin-film solar battery.
[0061] According to the present invention, there may be also
provided a polyimide precursor resin composition for flexible
device substrates which comprises an aqueous solvent and has good
environmental acceptability, and may provide a polyimide substrate
for flexible device having high transparency, and having excellent
properties such as flexibility, heat resistance, electrical
properties, and solvent resistance, and being suitably usable as a
substrate for flexible device as a display device such as
substrates for a liquid crystal display, an organic EL display and
an electronic paper, a substrate for flexible device as a
light-receiving device such as a substrate for a thin-film solar
battery, and the like, and preferably comprises a solvent
containing no organic solvent other than water. The polyimide
precursor resin composition for flexible device substrates is
preferred because of having high environmental acceptability as
compared with a polyimide precursor solution composition comprising
an organic solvent. Moreover, the polyimide substrate for flexible
device which is obtained from the polyimide precursor resin
composition and has a specific composition may have high
transparency, and have excellent properties such as flexibility,
heat resistance, electrical properties, and solvent resistance, and
therefore may be suitably used, for example, as a substrate for
flexible device which is a display device such as substrates for a
liquid crystal display, an organic EL display and an electronic
paper, and as a substrate for flexible device which is a
light-receiving device such as a substrate for a thin-film solar
battery, in particular, which requires particularly high
transparency and flexibility, and may be particularly suitably used
as a substrate for a flexible display.
[0062] Moreover, according to the present invention, there may be
provided a method for easily producing an aqueous polyimide
precursor solution composition, which has higher environmental
acceptability, without the need for a solvent other than water.
According to the production method, an aqueous polyimide precursor
solution composition, particularly an aqueous polyimide precursor
solution composition comprising an aqueous solvent which has an
organic solvent content of less than 5 wt %, further preferably
contains no organic solvent, may be very easily (directly)
produced. There have been no aqueous polyimide precursor solution
compositions having such an extremely low organic solvent content.
Now such an aqueous polyimide precursor solution composition may be
produced by the production method of the present invention, which
allows the reaction of a tetracarboxylic acid component and a
diamine component in an aqueous solvent to form a polyimide
precursor (polyamic acid).
DESCRIPTION OF EMBODIMENTS
[0063] According to the present invention, an aqueous polyimide
precursor solution composition is produced by reacting a
tetracarboxylic dianhydride and a diamine in the presence of an
imidazole, using water as a reaction solvent, provided that
[0064] not more than 50 mol %, including 0 mol %, of the
tetracarboxylic dianhydride to be reacted is an aromatic
tetracarboxylic dianhydride containing no fluorine group,
preferably an aromatic tetracarboxylic dianhydride having two to
three aromatic rings and containing no fluorine group, and not less
than 50 mol % of the tetracarboxylic dianhydride to be reacted is
an aliphatic tetracarboxylic dianhydride and/or an aromatic
tetracarboxylic dianhydride containing a fluorine group, or
[0065] not more than 50 mol %, including 0 mol %, of the diamine to
be reacted is an aromatic diamine having a solubility in water at
25.degree. C. of 0.1 g/L or more and containing no fluorine group,
preferably an aromatic diamine having one to two aromatic rings,
and having a solubility in water at 25.degree. C. of 0.1 g/L or
more and containing no fluorine group, and not less than 50 mol %
of the diamine to be reacted is an aliphatic diamine having a
molecular weight of 500 or less and/or an aromatic diamine
containing a fluorine group, preferably an aromatic diamine having
one to two aromatic rings, and containing a fluorine group.
It may be included that
[0066] not more than 50 mol % of the tetracarboxylic dianhydride to
be reacted is an aromatic tetracarboxylic dianhydride containing no
fluorine group, preferably an aromatic tetracarboxylic dianhydride
having two to three aromatic rings and containing no fluorine
group, and not less than 50 mol % of the tetracarboxylic
dianhydride to be reacted is an aliphatic tetracarboxylic
dianhydride and/or an aromatic tetracarboxylic dianhydride
containing a fluorine group, and
[0067] not more than 50 mol % of the diamine to be reacted is an
aromatic diamine having a solubility in water at 25.degree. C. of
0.1 g/L or more and containing no fluorine group, preferably an
aromatic diamine having one to two aromatic rings, and having a
solubility in water at 25.degree. C. of 0.1 g/L or more and
containing no fluorine group, and not less than 50 mol % of the
diamine to be reacted is an aliphatic diamine having a molecular
weight of 500 or less and/or an aromatic diamine containing a
fluorine group, preferably an aromatic diamine having one to two
aromatic rings, and containing a fluorine group.
[0068] The term "using water as a reaction solvent" means that
water is used as the main component of the solvent. Therefore, an
organic solvent other than water may be used in a ratio of 50 wt %
or less, preferably 30 wt % or less, more preferably 10 wt % or
less, relative to the whole solvent. The "organic solvent" as used
herein does not include a tetracarboxylic acid component such as
tetracarboxylic dianhydride, a diamine component, a polyimide
precursor such as polyamic acid, and an imidazole.
[0069] Examples of the organic solvent include
N,N-dimethylformamide, N,N-dimethylacetamide, N,
N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone,
1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam,
hexamethylphosphoric triamide, 1,2-dimethoxyethane,
bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane,
tetrahydrofuran, bis[2-(2-methoxyethoxy)ethyl]ether, 1,4-dioxane,
dimethyl sulfoxide, dimethyl sulfone, diphenyl ether, sulfolane,
diphenyl sulfone, tetramethylurea, anisole, m-cresol, phenol, and
.gamma.-butyrolactone.
[0070] In the method for producing an aqueous polyimide precursor
solution composition of the present invention, the reaction solvent
is preferably a solvent having an organic solvent content of less
than 5 wt %, particularly preferably an aqueous solvent containing
no organic solvent other than water, in view of high environmental
acceptability. The composition of the reaction solvent may be
appropriately selected depending on the intended solvent
composition of the aqueous polyimide precursor solution composition
to be produced, and it may be preferably the same as the intended
solvent composition of the aqueous polyimide precursor solution
composition.
[0071] Preferable examples of the imidazole (compound) used in the
present invention include a compound represented by the following
formula (10).
##STR00003##
[0072] In the formula (10), X.sub.1 to X.sub.4 each independently
represents a hydrogen atom or an alkyl group having 1 to 5 carbon
atoms.
[0073] The imidazole used in the present invention preferably has a
solubility in water at 25.degree. C. of 0.1 g/L or more,
particularly preferably 1 g/L or more.
[0074] In the imidazole of the formula (10), X.sub.1 to X.sub.4
each independently represents a hydrogen atom or an alkyl group
having 1 to 5 carbon atoms. An imidazole in which at least two of
X.sub.1 to X.sub.4 are alkyl groups having 1 to 5 carbon atoms, or
an imidazole having two or more alkyl groups as substituents is
more preferred.
[0075] An imidazole having two or more alkyl groups as substituents
has high solubility in water, and therefore, when using such an
imidazole, an aqueous polyimide precursor solution composition may
be easily produced. Preferable examples of the imidazole include
1,2-dimethylimidazole (solubility in water at 25.degree. C.; 239
g/L; the same shall apply hereinafter), 2-ethyl-4-methylimidazole
(1000 g/L), 4-ethyl-2-methylimidazole (1000 g/L), and
1-methyl-4-ethylimidazole (54 g/L).
[0076] The "solubility in water at 25.degree. C." means the maximum
amount (g) of the substance soluble in 1 L (liter) of water at
25.degree. C. This value may be easily searched using
SciFinder.RTM., which is known as a search service based on the
data bases such as Chemical Abstracts. Among the various values of
solubility under various conditions, the values at pH 7, which are
calculated by Advanced Chemistry Development (ACD/Labs) Software
V11.02 (Copyright 1994-2011 ACD/Labs), are used herein.
[0077] The imidazole to be used may be a single imidazole, or may
be a mixture of two or more imidazoles.
[0078] The amount of the imidazole used in the present invention is
preferably 0.8 equivalents or more, more preferably 1.0 equivalent
or more, further preferably 1.2 equivalents or more per equivalent
of the carboxyl group of the polyamic acid, which is formed by the
reaction of a tetracarboxylic dianhydride and a diamine as starting
materials. When the amount of the imidazole used is less than 0.8
equivalents per equivalent of the carboxyl group of the polyamic
acid, it may not be easy to provide an aqueous polyimide precursor
solution composition in which the polyamic acid is homogeneously
dissolved. In addition, the upper limit of the amount of the
imidazole used may be generally, but not limited to, less than 10
equivalents, preferably less than 5 equivalents, more preferably
less than 3 equivalents per equivalent of the carboxyl group of the
polyamic acid. If the amount of the imidazole used is too great, it
will be uneconomical, and the storage stability of the aqueous
polyimide precursor solution composition may be reduced.
[0079] In the present invention, the "equivalents per equivalent of
the carboxyl group of the polyamic acid", which defines the amount
of the imidazole, means the number (number of molecules) of
imidazole used per one carboxyl group to form an amic acid group in
the polyamic acid. The number of carboxyl groups to form amic acid
groups in the polyamic acids may be calculated on the assumption
that two carboxyl groups would be formed per one molecule of the
tetracarboxylic acid component as a starting material.
[0080] Accordingly, the amount of the imidazole used in the present
invention is preferably 1.6 mole or more, more preferably 2.0 mole
or more, further preferably 2.4 mole or more per mole of the
tetracarboxylic dianhydride as a starting material (per mole of the
tetracarboxylic acid component of the polyamic acid).
[0081] The characteristics of the imidazole used in the present
invention are that the imidazole forms a salt with a carboxyl group
of a polyamic acid (polyimide precursor), which is formed by the
reaction of a tetracarboxylic dianhydride and a diamine as starting
materials, thereby increasing the solubility of the polyamic acid
in water, and also that the imidazole exhibits a very high
catalytic activity during the imidization (dehydration/ring
closure) of the polyimide precursor to form a polyimide.
Consequently, when using the aqueous polyimide precursor solution
composition of the present invention, a polyimide and a substrate
for flexible devices, which have very high properties, may be
easily produced even though the aqueous polyimide precursor
solution composition is heated at a lower temperature for a shorter
period of time, for example.
[0082] As described above, according to the present invention, an
aqueous polyimide precursor solution composition may be very easily
(directly) produced preferably by reacting a tetracarboxylic acid
component and a diamine component in the presence of an imidazole,
preferably in the presence of an imidazole having two or more alkyl
groups as substituents, using water as a reaction solvent.
[0083] The reaction is performed at a relatively low temperature of
100.degree. C. or lower, preferably 80.degree. C. or lower, so as
to suppress the imidization reaction, using substantially equimolar
amounts of a tetracarboxylic acid component (tetracarboxylic
dianhydride) and a diamine component. The reaction temperature may
be generally, but not limited to, from 25.degree. C. to 100.degree.
C., preferably from 40.degree. C. to 80.degree. C., more preferably
from 50.degree. C. to 80.degree. C. The reaction time may be
preferably, but not limited to, from about 0.1 hours to about 24
hours, preferably from about 2 hours to about 12 hours. When
setting the reaction temperature and the reaction time within the
ranges as described above, an aqueous polyimide precursor solution
composition which comprises a polyimide precursor having a high
molecular weight may be easily produced with good production
efficiency. In general, the reaction may be preferably performed in
an inert gas atmosphere, preferably in a nitrogen gas atmosphere,
although the reaction may be performed in an air atmosphere.
[0084] In addition, the "substantially equimolar amounts of a
tetracarboxylic acid component (tetracarboxylic dianhydride) and a
diamine component" specifically means that a molar ratio
[tetracarboxylic acid component/diamine component] is from about
0.90 to about 1.10, preferably from about 0.95 to about 1.05.
[0085] As for the tetracarboxylic dianhydride used in the present
invention, not less than 50 mol % thereof is an aliphatic
tetracarboxylic dianhydride and/or an aromatic tetracarboxylic
dianhydride containing a fluorine group, and not more than 50 mol %
thereof is an aromatic tetracarboxylic dianhydride containing no
fluorine group, preferably an aromatic tetracarboxylic dianhydride
containing no fluorine group and having two to three aromatic
rings. However, an aromatic tetracarboxylic dianhydride containing
no fluorine group only, or alternatively, a tetracarboxylic acid
component comprising an aromatic tetracarboxylic dianhydride
containing no fluorine group in an amount of not less than 50 mol %
and an aliphatic tetracarboxylic dianhydride and/or an aromatic
tetracarboxylic dianhydride containing a fluorine group in an
amount of not more than 50 mol % may be used, when not less than 50
mol % of the diamine component to be reacted is an aliphatic
diamine having a molecular weight of 500 or less and/or an aromatic
diamine containing a fluorine group and not more than 50 mol % of
the diamine component to be reacted is an aromatic diamine
containing no fluorine group and having a solubility in water at
25.degree. C. of 0.1 g/L or more.
[0086] Preferable examples of the aromatic tetracarboxylic
dianhydride containing no fluorine group used in the present
invention include 3,3',4,4'-biphenyltetracarboxylic dianhydride,
2,3,3',4'-biphenyltetracarboxylic dianhydride,
2,2',3,3'-biphenyltetracarboxylic dianhydride, pyromellitic
dianhydride, benzophenone tetracarboxylic dianhydride,
4,4'-oxydiphthalic dianhydride, diphenylsulfone tetracarboxylic
dianhydride, p-terphenyl tetracarboxylic dianhydride, and
m-terphenyl tetracarboxylic dianhydride.
[0087] Preferable examples of the aliphatic tetracarboxylic
dianhydride used in the present invention include
cyclobutane-1,2,3,4-tetracarboxylic dianhydride,
1,2,4,5-cyclohexane tetracarboxylic dianhydride,
dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride,
1,2,4,5-cyclohexane tetracarboxylic acid-1,2:4,5-dianhydride,
1,2,3,4-cyclobutane tetracarboxylic dianhydride, and
bicyclo[2.2.2]octo-7-ene-2,3;5,6-tetracarboxylic dianhydride.
[0088] Preferable examples of the aromatic tetracarboxylic
dianhydride containing a fluorine group used in the present
invention include 4,4'-(hexafluoroisopropylidene)diphthalic
anhydride, 3,3'-(hexafluoroisopropylidene)diphthalic anhydride,
5,5'-[2,2,2-trifluoro-1-[3-(trifluoromethyl)phenyl]ethylidene]diphthalic
anhydride,
5,5'-[2,2,3,3,3-pentafluoro-1-(trifluoromethyl)propylidene]diphthalic
anhydride, 1H-diflo[3,4-b:3',4'-i]xanthene-1,3,7,9(11H)-tetron,
5,5'-oxybis[4,6,7-trifluoro-pyromellitic anhydride],
3,6-bis(trifluoromethyl)pyromellitic dianhydride,
4-(trifluoromethyl)pyromellitic dianhydride,
1,4-difluoropyromellitic dianhydride, and
1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene
dianhydride.
[0089] The aromatic tetracarboxylic dianhydride containing no
fluorine group, the aliphatic tetracarboxylic dianhydride, and the
aromatic tetracarboxylic dianhydride containing a fluorine group
each may not be a single component, and may be a mixture of two or
more types thereof.
[0090] As for the diamine used in the present invention, not less
than 50 mol % thereof is an aliphatic diamine having a molecular
weight of 500 or less and/or an aromatic diamine containing a
fluorine group, preferably an aromatic diamine containing a
fluorine group and having one to two aromatic rings, and not more
than 50 mol % thereof is an aromatic diamine having a solubility in
water at 25.degree. C. of 0.1 g/L or more and containing no
fluorine group, preferably an aromatic diamine having a solubility
in water at 25.degree. C. of 0.1 g/L or more and containing no
fluorine group and having one to two aromatic rings. However, an
aromatic diamine containing no fluorine group only, or
alternatively, a diamine component comprising an aromatic diamine
containing no fluorine group in an amount of not less than 50 mol %
and an aliphatic diamine and/or an aromatic diamine containing a
fluorine group in an amount of not more than 50 mol % may be used,
when not less than 50 mol % of the tetracarboxylic acid component
to be reacted is an aliphatic tetracarboxylic dianhydride and/or an
aromatic tetracarboxylic dianhydride containing a fluorine group
and not more than 50 mol % of the tetracarboxylic acid component to
be reacted is an aromatic tetracarboxylic dianhydride containing no
fluorine group.
[0091] The aromatic diamine containing no fluorine group used in
the present invention is not limited as long as the solubility in
water at 25.degree. C. is 0.1 g/L or more, but may be preferably an
aromatic diamine having one to two aromatic rings. When an aromatic
diamine having a solubility in water at 25.degree. C. of less than
0.1 g/L is used, it may be difficult to provide an aqueous
polyimide precursor solution composition in which the polyimide
precursor is homogeneously dissolved. Meanwhile, when the aromatic
diamine has more than two aromatic rings, the aromatic diamine may
have a solubility in water at 25.degree. C. of less than 0.1 g/L,
and therefore it may be difficult to provide an aqueous polyimide
precursor solution composition in which the polyimide precursor is
homogeneously dissolved.
[0092] The aliphatic diamine used in the present invention is not
limited as long as the molecular weight (which means "molecular
weight" in the case of monomer, and "weight average molecular
weight" in the case of polymer) is 500 or less, but may be
preferably an aliphatic diamine having a solubility in water at
25.degree. C. of 0.1 g/L or more, or an alicyclic diamine having
one to two alicyclic rings. When an aliphatic diamine having a
molecular weight of more than 500 is used, it may be difficult to
provide an aqueous polyimide precursor solution composition in
which the polyimide precursor is homogeneously dissolved.
[0093] The aromatic diamine containing a fluorine group used in the
present invention may be preferably, but not limited to, an
aromatic diamine having one to two aromatic rings and containing a
fluorine group. When the aromatic diamine containing a fluorine
group has more than two aromatic rings, it may be difficult to
provide an aqueous polyimide precursor solution composition in
which the polyimide precursor is homogeneously dissolved.
[0094] Preferable examples of the aromatic diamine containing no
fluorine group used in the present invention include
p-phenylenediamine (solubility in water at 25.degree. C.: 120 g/L;
the same shall apply hereinafter), m-phenylenediamine (77 g/L),
4,4'-diaminodiphenyl ether (0.19 g/L), 3,4'-diaminodiphenyl ether
(0.24 g/L), 4,4'-diaminodiphenylmethane (0.54 g/L),
2,4-toluenediamine (62 g/L), 3,3'-dihydroxy-4,4'-diaminobiphenyl
(1.3 g/L), bis(4-amino-3-carboxyphenyl)methane (200 g/L), and
2,4-diaminotoluene (62 g/L). Among them, in terms of the high
solubility in water, and excellent properties of the polyimide
obtained, p-phenylenediamine, m-phenylenediamine,
4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and a
mixture thereof are preferred, and p-phenylenediamine,
4,4'-diaminodiphenyl ether, and a mixture thereof are more
preferred.
[0095] Preferable examples of the aliphatic diamine used in the
present invention include trans-1,4-diaminocyclohexane (1000 g/L,
molecular weight: 114), cis-1,4-diaminocyclohexane (1000 g/L,
molecular weight: 114), 1,6-hexamethylene diamine (1000 g/L,
molecular weight: 116), 1,10-decamethylene diamine (1000 g/L,
molecular weight: 172), 1,3-bis(aminomethyl)cyclohexane (1000 g/L,
molecular weight: 142), 1,4-bis(aminomethyl)cyclohexane (999 g/L,
molecular weight: 142), and polyoxypropylene diamine having a
weight average molecular weight of 500 or less.
[0096] Preferable examples of the aromatic diamine containing a
fluorine group used in the present invention include
2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl,
2,3,5,6-tetrafluoro-1,4-diaminobenzene,
2,4,5,6-tetrafluoro-1,3-diaminobenzene,
2,3,5,6-tetrafluoro-1,4-benzene(dimethaneamine),
2,2'-difluoro-(1,1'-biphenyl)-4,4'-diamine,
2,2',6,6'-tetrafluoro-(1,1'-biphenyl)-4,4'-diamine, 4,4'-diamino
octafluorobiphenyl, 2,2-bis(4-aminophenyl) hexafluoropropane, and
4,4'-oxybis(2,3,5,6-tetrafluoroaniline).
[0097] The aromatic diamine containing no fluorine group, the
aliphatic diamine, and the aromatic diamine containing a fluorine
group each may not be a single component, and may be a mixture of
two or more types thereof. As for the aromatic diamine containing
no fluorine group, it is also possible to use a diamine which has a
high solubility in water in combination with other diamines such
that the diamine component has a solubility in water at 25.degree.
C. of 0.1 g/L or more as a whole.
[0098] The "diamine having a solubility in water at 25.degree. C.
of 0.1 g/L or more" means that 0.1 g or more of the diamine is
dissolved in 1 L (1000 ml) of water at 25.degree. C. The
"solubility in water at 25.degree. C." means the maximum amount (g)
of the substance soluble in 1 L (liter) of water at 25.degree. C.
This value may be easily searched using SciFinder.RTM., which is
known as a search service based on the data bases such as Chemical
Abstracts. Among the various values of solubility under various
conditions, the values at pH 7, which are calculated by Advanced
Chemistry Development (ACD/Labs) Software V11.02 (Copyright
1994-2011 ACD/Labs), are used herein.
[0099] The polyamic acid which constitutes the aqueous polyimide
precursor solution composition of the present invention consists of
a repeating unit represented by the formula (1).
[0100] In the formula (1), the "A" group is a chemical structure
derived from the tetracarboxylic acid component of a polyamic acid,
and is a tetravalent group of an aromatic tetracarboxylic acid
containing no fluorine group and preferably having two to three
aromatic rings, from which carboxyl groups have been removed,
and/or a tetravalent group of an aliphatic tetracarboxylic acid,
from which carboxyl groups have been removed, and/or a tetravalent
group of an aromatic tetracarboxylic acid containing a fluorine
group, from which carboxyl groups have been removed.
[0101] As for the "A" group in the formula (1), not more than 50
mol % of A is preferably a tetravalent group of an aromatic
tetracarboxylic acid containing no fluorine group and preferably
having two to three aromatic rings, from which carboxyl groups have
been removed, and not less than 50 mol % of A is preferably a
tetravalent group of an aliphatic tetracarboxylic acid, from which
carboxyl groups have been removed, and/or a tetravalent group of an
aromatic tetracarboxylic acid containing a fluorine group, from
which carboxyl groups have been removed, so as to provide a
polyamic acid having an adequate solubility in water, and to
provide a polyimide having high transparency, thereby easily
producing a polyimide substrate for flexible devices, and the like,
which have high properties. When not less than 50 mol % of B in the
formula (1) is a divalent group of an aliphatic diamine having a
molecular weight of 500 or less, from which amino groups have been
removed, and/or a divalent group of an aromatic diamine containing
a fluorine group, from which amino groups have been removed, and
not more than 50 mol % of B is a divalent group of an aromatic
diamine containing no fluorine group and having a solubility in
water at 25.degree. C. of 0.1 g/L or more, from which amino groups
have been removed, however, the "A" group is not limited, and not
less than 50 mol % of A may be a tetravalent group of an aromatic
tetracarboxylic acid containing no fluorine group, from which
carboxyl groups have been removed, and not more than 50 mol % of A
may be a tetravalent group of an aliphatic tetracarboxylic acid,
from which carboxyl groups have been removed, and/or a tetravalent
group of an aromatic tetracarboxylic acid containing a fluorine
group, from which carboxyl groups have been removed.
[0102] In the present invention, in terms of the properties of the
polyimide obtained, the "A" group in the formula (1) which is a
constituent unit derived from the aromatic tetracarboxylic
dianhydride containing no fluorine group is preferably any one or
more of the groups represented by the following formulas (2) to
(7), particularly preferably any one or more of the groups
represented by the following formulas (2), (3) and (5) in the main,
further preferably any one or more of the groups represented by the
following formulas (2) to (3).
##STR00004##
[0103] In the formula (1), the "B" group is a chemical structure
derived from the diamine component of a polyamic acid, and is a
divalent group of an aromatic diamine having a solubility in water
at 25.degree. C. of 0.1 g/L or more and containing no fluorine
group and preferably having one to two aromatic rings, from which
amino groups have been removed, and/or a divalent group of an
aliphatic diamine having a molecular weight of 500 or less,
preferably an aliphatic diamine having a solubility in water of 0.1
g/L or more, or an aliphatic diamine having one to two alicyclic
rings, from which amino groups have been removed, and/or a divalent
group of an aromatic diamine containing a fluorine group,
preferably an aromatic diamine containing a fluorine group and
having one to two aromatic rings, from which amino groups have been
removed.
[0104] As for the "B" group in the formula (1), not more than 50
mol % of B is preferably a divalent group of an aromatic diamine
having a solubility in water at 25.degree. C. of 0.1 g/L or more
and containing no fluorine group and preferably having one to two
aromatic rings, from which amino groups have been removed, and not
less than 50 mol % of B is preferably a divalent group of an
aliphatic diamine having a molecular weight of 500 or less, from
which amino groups have been removed, and/or a divalent group of an
aromatic diamine containing a fluorine group, from which amino
groups have been removed, so as to provide a polyamic acid having
an adequate solubility in water, and to provide a polyimide having
high transparency, thereby easily producing a polyimide substrate
for flexible devices, and the like, which have high properties.
When not less than 50 mol % of A in the formula (1) is a
tetravalent group of an aliphatic tetracarboxylic acid, from which
carboxyl groups have been removed, and/or a tetravalent group of an
aromatic tetracarboxylic acid containing a fluorine group, from
which carboxyl groups have been removed, and not more than 50 mol %
of A is a tetravalent group of an aromatic tetracarboxylic acid
containing no fluorine group, from which carboxyl groups have been
removed, however, the "B" group is not limited, and not less than
50 mol % of B may be a divalent group of an aromatic diamine
containing no fluorine group and having a solubility in water at
25.degree. C. of 0.1 g/L or more, from which amino groups have been
removed, and not more than 50 mol % of B may be a divalent group of
an aliphatic diamine having a molecular weight of 500 or less, from
which amino groups have been removed, and/or a divalent group of an
aromatic diamine containing a fluorine group, from which amino
groups have been removed.
[0105] In the present invention, in terms of the properties of the
polyimide obtained, the "B" group in the formula (1) which is a
constituent unit derived from the aromatic diamine containing no
fluorine group is preferably any one or more of the groups
represented by the following formulas (8) to (9).
##STR00005##
[0106] In the aqueous polyimide precursor solution composition
obtained according to the present invention, the polyimide
precursor (which is substantially a polyamic acid) may preferably
have a high molecular weight; specifically, the inherent viscosity
may be preferably, but not limited to, 0.2 or more, preferably 0.4
or more, more preferably 0.6 or more, further preferably 0.8 or
more, particularly preferably 1.0 or more, or more than 1.0,
wherein the inherent viscosity is measured at a temperature of
30.degree. C. and a concentration of 0.5 g/100 mL (dissolved in
water) which is based on the solid content of the polyimide
precursor. In one embodiment, when the inherent viscosity is lower
than the range as described above, it may be difficult to provide a
polyimide, a polyimide substrate for flexible devices, and the
like, which have high properties, even if the aqueous polyimide
precursor solution composition of the present invention is used,
because the polyimide precursor has a low molecular weight.
[0107] The solid content based on the polyimide precursor (which is
substantially a polyamic acid) of the aqueous polyimide precursor
solution composition of the present invention may be preferably,
but not limited to, from 5 wt % to 45 wt %, more preferably from 7
wt % to 40 wt %, further preferably from 9 wt % to 30 wt %,
relative to the total amount of the polyimide precursor and the
solvent. When the solid content is lower than 5 wt %, the
productivity and the handling in use may be reduced. When the solid
content is higher than 45 wt %, the solution may lose the
fluidity.
[0108] In view of handling properties, the solution viscosity at
30.degree. C. of the aqueous polyimide precursor solution
composition of the present invention may be preferably, but not
limited to, 1000 Pasec or lower, more preferably from 0.1 Pasec to
500 Pasec, further preferably from 0.1 Pasec to 300 Pasec,
particularly preferably from 0.1 Pasec to 200 Pasec. When the
solution viscosity is higher than 1000 Pasec, the composition may
lose the fluidity, and therefore it may be difficult to uniformly
apply the composition onto a metal, a glass, and the like. When the
solution viscosity is lower than 0.1 Pasec, dripping, cissing, and
the like may occur when applying the composition onto a metal, a
glass, and the like, and it may be difficult to provide a
polyimide, a polyimide substrate for flexible devices, and the
like, which have high properties.
[0109] Although the aqueous polyimide precursor solution
composition of the present invention comprises an aqueous solvent,
an organic solvent other than water, for example, a known organic
solvent to be used in the preparation of a polyamic acid may be
used in a ratio of 50 wt % or less, preferably 30 wt % or less,
more preferably 10 wt % or less, relative to the whole solvent. In
other words, the aqueous polyimide precursor solution composition
of the present invention is a composition in which a polyamic acid
as a polyimide precursor is dissolved, together with an imidazole,
in an aqueous solvent (water-based solvent), wherein the aqueous
solvent is only water, or a mixture of water and an organic solvent
having a water content of 50 wt % or more, preferably 70 wt % or
more, more preferably 90 wt % or more.
[0110] Examples of the organic solvent include
N,N-dimethylformamide, N,N-dimethylacetamide, N,
N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone,
1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam,
hexamethylphosphoric triamide, 1,2-dimethoxyethane,
bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane,
tetrahydrofuran, bis[2-(2-methoxyethoxy)ethyl]ether, 1,4-dioxane,
dimethyl sulfoxide, dimethyl sulfone, diphenyl ether, sulfolane,
diphenyl sulfone, tetramethylurea, anisole, m-cresol, phenol, and
.gamma.-butyrolactone.
[0111] In the aqueous polyimide precursor solution composition of
the present invention, the solvent is particularly preferably a
solvent having an organic solvent content of less than 5 wt %, more
preferably an aqueous solvent containing no organic solvent other
than water, i.e. only water, in view of environmental
acceptability.
[0112] The aqueous polyimide precursor solution composition of the
present invention may also be prepared according to the following
methods, for example, as described in Patent Literatures 4 and
5:
[0113] (i) a method, comprising [0114] pouring a polyamide acid,
which is prepared by reacting a tetracarboxylic acid component with
a diamine component in an organic solvent as a reaction solvent,
into water to provide a polyamide acid powder; and [0115] mixing
and dissolving the polyamide acid powder, together with an
imidazole (preferably, an imidazole having two or more alkyl
groups), into an aqueous solvent to provide an aqueous solution
composition;
[0116] (ii) a method, comprising [0117] reacting a tetracarboxylic
acid component with a diamine component in an organic solvent as a
reaction solvent in the presence of an imidazole (preferably, an
imidazole having two or more alkyl groups) to provide a
water-soluble polyimide precursor; [0118] separating the
water-soluble polyimide precursor therefrom; and [0119] dissolving
the separated water-soluble polyimide precursor in an aqueous
solvent; and
[0120] (iii) a method, comprising [0121] reacting a tetracarboxylic
acid component with a diamine component in an organic solvent as a
reaction solvent to provide a polyamic acid; [0122] reacting the
polyamic acid with an imidazole (preferably, an imidazole having
two or more alkyl groups) in an organic solvent as a reaction
solvent to provide a water-soluble polyimide precursor; [0123]
separating the water-soluble polyimide precursor therefrom; and
[0124] dissolving the separated water-soluble polyimide precursor
in an aqueous solvent. As described above, however, in order to
obtain an aqueous polyimide precursor solution composition having
an extremely low organic solvent content, or containing no organic
solvent, it is not preferred that a polyimide precursor is prepared
in an organic solvent.
[0125] Generally, a polyimide may be suitably prepared by heating
the aqueous polyimide precursor solution composition of the present
invention to remove an aqueous solvent and effect imidization
(dehydration/ring closure). The heat treatment conditions are not
limited, but, in general, the aqueous polyimide precursor solution
composition may be preferably heated at a temperature of
100.degree. C. or higher, preferably from 120.degree. C. to
600.degree. C., more preferably from 150.degree. C. to 500.degree.
C., further preferably from 150.degree. C. to 350.degree. C., for
from 0.01 hours to 30 hours, preferably from 0.01 hours to 10
hours, preferably while increasing the temperature stepwise.
[0126] The heat treatment may be suitably performed under
atmospheric pressure, and may be performed under reduced pressure
so as to efficiently remove the aqueous solvent. The aqueous
polyimide precursor solution composition may be heated at a
relatively low temperature under reduced pressure at the early
stage for deaeration. When the heating temperature is rapidly
increased, a problem such as foaming may occur, and therefore a
polyimide having good properties may not be obtained.
[0127] The aqueous polyimide precursor solution composition of the
present invention may be heated at a relatively low temperature
(for example, 150.degree. C. to 300.degree. C., preferably
180.degree. C. to 250.degree. C.) to readily provide a polyimide,
which is in no way inferior to a polyimide obtained from a
commonly-used polyimide precursor (polyamic acid) solution
composition comprising an organic solvent, and has excellent
properties.
[0128] A polyimide obtained from the aqueous polyimide precursor
solution composition of the present invention may have high
transparency. According to the present invention, there may be
provided a polyimide film which has a light transmittance at 400 nm
of 60% or more, further 70% or more, further 80% or more, further
85% or more, in terms of 10 .mu.m of film thickness, for example,
using the aqueous polyimide precursor solution composition of the
present invention. According to the present invention, there may be
also provided a polyimide film which has a total light
transmittance of 80% or more, further 85% or more, further 90% or
more, in terms of 10 .mu.m of film thickness, for example, using
the aqueous polyimide precursor solution composition of the present
invention.
[0129] Because a polyimide obtained from the aqueous polyimide
precursor solution composition of the present invention may have
high transparency, the polyimide may be suitably used for an
electrical device, an electronic device, and an optical device,
which require transparency, and may be suitably used, for example,
as a substrate, or a protective film for a display device such as a
liquid crystal display, an EL display and an electronic paper, a
touch panel, a solar battery, or an LED lighting device, or the
like. The polyimide may be particularly suitably used as a
substrate of a flexible device, for example, a display device such
as a liquid crystal display, an organic EL display and an
electronic paper, and a light-receiving device such as a
light-receiving element of a thin-film solar battery.
[0130] The aqueous polyimide precursor solution composition of the
present invention may contain other additive component(s) depending
on the intended application of the polyimide obtained.
[0131] The aqueous polyimide precursor solution composition of the
present invention may be particularly suitably used as a polyimide
precursor resin composition for flexible device substrates.
[0132] According to the method for producing the flexible device of
the present invention, a coating film of an aqueous polyimide
precursor solution composition layer is formed on a substrate by
applying or spraying an aqueous polyimide precursor solution
composition (specifically, an aqueous polyimide precursor solution
composition in which a polyamic acid consisting of a repeating unit
represented by the formula (1) is homogeneously dissolved in an
aqueous solvent together with an imidazole in an amount of 1.6 mole
or more per mole of the tetracarboxylic acid component of the
polyamic acid) onto the substrate surface, and then the aqueous
polyimide precursor solution composition is heated to provide a
polyimide substrate for flexible devices.
[0133] According to the present invention, a polyimide substrate
for flexible devices may be suitably prepared by heating the
aqueous polyimide precursor solution composition to remove an
aqueous solvent and effect imidization (dehydration/ring closure).
The heat treatment conditions are not limited, but, in general, the
aqueous polyimide precursor solution composition may be preferably
heated at a temperature of 100.degree. C. or higher, preferably
from 120.degree. C. to 600.degree. C., more preferably from
150.degree. C. to 500.degree. C., further preferably from
150.degree. C. to 350.degree. C., for from 0.01 hours to 30 hours,
preferably from 0.01 hours to 10 hours, preferably while increasing
the temperature stepwise.
[0134] The heat treatment may be suitably performed under
atmospheric pressure, and may be performed under reduced pressure
so as to efficiently remove the aqueous solvent. The aqueous
polyimide precursor solution composition may be heated at a
relatively low temperature under reduced pressure at the early
stage for deaeration. When the heating temperature is rapidly
increased, a problem such as foaming may occur, and therefore a
good flexible device substrate may not be obtained.
[0135] According to the method for producing the polyimide
substrate for flexible devices of the present invention, the
aqueous polyimide precursor solution composition may be heated at a
relatively low temperature (for example, 150.degree. C. to
300.degree. C., preferably 180.degree. C. to 250.degree. C.) to
readily provide a polyimide substrate for flexible devices, which
has excellent properties, and is in no way inferior to a polyimide
substrate obtained from a commonly-used polyimide precursor
(polyamic acid) solution composition comprising an organic
solvent.
[0136] According to the method for producing the flexible device of
the present invention, a solid polyimide resin film is formed on a
carrier substrate as a support by applying a polyimide precursor
resin composition (aqueous polyimide precursor solution
composition) onto the carrier substrate, and heating the
composition; a circuit is formed on the polyimide resin film; and
then the polyimide resin film on which the circuit is formed is
separated from the carrier substrate.
[0137] Any method for applying an aqueous polyimide precursor
solution composition may be applied, as long as a coating film
having a uniform thickness is formed on a carrier substrate
(support). For example, die coating, spin coating, and screen
printing may be employed for the application.
[0138] A substrate for flexible devices may be suitably produced by
a method, comprising
[0139] forming a coating film of an aqueous polyimide precursor
solution composition on a carrier substrate;
[0140] heating the coating film at a relatively low temperature to
effect the removal of the aqueous solvent, thereby forming a
self-supporting film (the film in a state of not flowing; the
polymerization and partial imidization reaction, as well as the
removal of the aqueous solvent, proceed); and
[0141] heating the self-supporting film on the substrate, or
alternatively, the self-supporting film which is peeled from the
substrate, if necessary, to effect dehydration/imidization.
The terms "removal of the aqueous solvent" and
"dehydration/imidization" as used herein do not mean that only the
removal of the aqueous solvent proceeds and only the
dehydration/imidization proceeds, respectively, in the steps. In
the aqueous solvent removal step, the dehydration/imidization
proceeds to some extent. In the dehydration/imidization step, the
removal of the residual aqueous solvent proceeds.
[0142] The aqueous polyimide precursor solution composition of the
present invention may contain other additive component(s) depending
on the intended application of the polyimide substrate for flexible
devices obtained. Additionally, another resin layer may be
laminated on the polyimide substrate for flexible devices
obtained.
[0143] In the method for producing the flexible device of the
present invention, the thickness of the polyimide resin film is
desirably from 1 .mu.m to 20 .mu.m. When the thickness is less than
1 .mu.m, the polyimide resin film may not remain adequately
resistant, and therefore the polyimide resin film may not withstand
stress and may be broken when used as a flexible device substrate.
When the thickness of the polyimide resin film is more than 20
.mu.m and greater, it may be difficult to achieve the thinning of
the flexible device. The thickness of the polyimide resin film is
more desirably from 2 .mu.m to 10 .mu.m so as to achieve the
further thinning, while maintaining an adequate resistance for the
flexible device.
[0144] According to the method for producing the flexible device of
the present invention, a circuit needed for a display device or a
light-receiving device is formed on the polyimide resin film formed
as described above. This step differs from device to device. For
example, in the case of the production of a TFT liquid crystal
display device, a TFT of amorphous silicon, for example, is formed
on the polyimide resin film. The TFT comprises a gate metal layer,
a silicon nitride gate dielectric layer, and an ITI pixel
electrode. In addition, a structure needed for a liquid crystal
display may be formed thereon by a known method. The method for
forming a circuit, and the like is not limited because the
polyimide resin film obtained according to the present invention
has excellent properties such as heat resistance, and
toughness.
[0145] The polyimide resin film on which the circuit etc. is formed
as described above is separated from the carrier substrate. The
method for the separation is not limited. For example, the
polyimide resin film on which the circuit is formed may be
separated from the carrier substrate by irradiation with laser or
the like from the carrier substrate side. Because the polyimide
resin film obtained according to the present invention has high
flexibility and toughness, it may be physically separated from the
carrier substrate (support) simply.
[0146] Examples of the flexible device in the present invention
include display devices such as a liquid crystal display, an
organic EL display and an electronic paper, and light-receiving
devices such as a solar battery and CMOS. The present invention may
be particularly suitably applied to devices to be thinner and
flexible.
EXAMPLES
[0147] Hereinafter, the present invention will be more specifically
described with reference to Examples and Comparative Examples, but
the present invention is not limited to these Examples.
[0148] The methods for measuring the properties, which was used in
the following examples, will be described below.
<Solid Content>
[0149] A sample solution (the weight is referred to as "w1") was
heated at 120.degree. C. for 10 minutes, 250.degree. C. for 10
minutes, and then 350.degree. C. for 30 minutes in a hot air dryer,
and the weight of the sample after the heat treatment (the weight
is referred to as "w2") was measured. The solid content [wt %] was
calculated by the following formula.
Solid content [wt %]=(w2/w1).times.100
<Inherent Viscosity>
[0150] A sample solution was diluted to a concentration of 0.5 g/dl
based on the solid content (the solvent: water). The flowing time
(T.sub.1) of the diluted solution was measured at 30.degree. C.
using a Cannon-Fenske viscometer No. 100. The inherent viscosity
was calculated by the following formula using the flowing time
(T.sub.0) of the blank water.
Inherent viscosity={ln(T.sub.1/T.sub.0)}/0.5
<Solution Viscosity (Rotational Viscosity)>
[0151] The solution viscosity was measured at 30.degree. C. using
an E type viscometer manufactured by Tokimec, Inc.
<Observation of State of Polyimide Substrate for Flexible
Device>
[0152] An article in which no defects such as foaming and crack
were observed was evaluated as .largecircle., and an article in
which defects such as foaming and crack were observed in not more
than 30% of the whole area was evaluated as .DELTA., and an article
in which defects such as foaming and crack were observed in more
than 30% of the whole area was evaluated as x.
<Measurement of Light Transmittance>
[0153] The total light transmittance and light transmittance at 400
nm in terms of 10 .mu.m of film thickness of the polyimide
substrate for flexible device were measured using a
light-transmittance measuring device (MCPD-300 manufactured by
Otsuka Electronics Co., Ltd.).
[0154] The abbreviations of the compounds used in the following
examples are as follows:
s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride ODPA:
4,4'-oxydiphthalic dianhydride 6FDA:
4,4'-(hexafluoroisopropylidene)diphthalic anhydride t-DCDA:
trans-dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride c-DCDA:
cis-dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride ODA:
4,4'-diaminodiphenyl ether (solubility in water at 25.degree. C.:
0.19 g/L) PPD: p-phenylenediamine (solubility in water at
25.degree. C.: 120 g/L) t-CHDA: trans-1,4-diaminocyclohexane
(solubility in water at 25.degree. C.: 1000 g/L, molecular weight:
114) HMD: 1,6-hexamethylene diamine (solubility in water at
25.degree. C.: 1000 g/L, molecular weight: 116) DAB:
1,4-diaminobutane (solubility in water at 25.degree. C.: 1000 g/L,
molecular weight: 88) DAP: 1,3-propanediamine (solubility in water
at 25.degree. C.: 1000 g/L, molecular weight: 74) D2000: JEFFAMINE
D2000 (manufactured by Mitsui Chemicals, Inc., diamine compound
having a weight average molecular weight of 2041) 1074: PRIAMINE
1074 (manufactured by Croda Japan KK, diamine compound having a
weight average molecular weight of 548) 1,2-DMZ:
1,2-dimethylimidazole (solubility in water at 25.degree. C.: 239
g/L)
Example 1
[0155] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.97 g (0.184 mol)
of t-CHDA, and 44.14 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.03 g (0.184 mol) of s-BPDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.8 wt %, a solution viscosity of 1.2
Pas, and an inherent viscosity of 0.72.
[0156] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0157] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 2
[0158] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 21.24 g (0.183 mol)
of HMD, and 43.92 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 53.76 g (0.183 mol) of s-BPDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.4 wt %, a solution viscosity of 0.7
Pas, and an inherent viscosity of 0.63.
[0159] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0160] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 3
[0161] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 17.29 g (0.196 mol)
of DAB, and 47.15 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 57.71 g (0.196 mol) of s-BPDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.2 wt %, a solution viscosity of 0.3
Pas, and an inherent viscosity of 0.45.
[0162] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0163] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 4
[0164] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.55 g (0.180 mol)
of t-CHDA, and 43.24 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 15.88 g (0.054 mol) of s-BPDA and 38.57 g (0.126 mol)
of c-DCDA were added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours to provide an aqueous
polyimide precursor solution having a solid content of 12.2 wt %, a
solution viscosity of 0.1 Pas, and an inherent viscosity of
0.27.
[0165] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0166] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 5
[0167] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.18 g (0.177 mol)
of t-CHDA, and 42.48 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.82 g (0.177 mol) of ODPA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.5 wt %, a solution viscosity of 0.1
Pas, and an inherent viscosity of 0.43.
[0168] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0169] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 6
[0170] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 23.31 g (0.116 mol)
of ODA, and 27.97 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 51.69 g (0.116 mol) of 6FDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 13.0 wt %, a solution viscosity of 2.5
Pas, and an inherent viscosity of 0.13.
[0171] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0172] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 7
[0173] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 14.69 g (0.136 mol)
of PPD, and 32.64 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 60.31 g (0.136 mol) of 6FDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 13.4 wt %, a solution viscosity of 4.5
Pas, and an inherent viscosity of 0.62.
[0174] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0175] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 8
[0176] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 15.34 g (0.134 mol)
of t-CHDA, and 32.28 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 59.66 g (0.134 mol) of 6FDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.2 wt %, a solution viscosity of 0.1
Pas, and an inherent viscosity of 0.40.
[0177] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0178] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-1.
Example 9
[0179] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.37 g (0.178 mol)
of t-CHDA, and 42.87 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.63 g (0.178 mol) of t-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.4 wt %, a solution viscosity of 0.5
Pas, and an inherent viscosity of 0.20.
[0180] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0181] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 10
[0182] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.63 g (0.178 mol)
of HMD, and 42.67 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.37 g (0.178 mol) of t-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.2 wt %, a solution viscosity of 0.6
Pas, and an inherent viscosity of 0.25.
[0183] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0184] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 11
[0185] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 16.76 g (0.190 mol)
of DAB, and 45.70 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 58.24 g (0.190 mol) of t-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.3 wt %, a solution viscosity of 0.4
Pas, and an inherent viscosity of 0.25.
[0186] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0187] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 12
[0188] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 14.61 g (0.197 mol)
of DAP, and 47.39 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 60.39 g (0.197 mol) of t-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.0 wt %, a solution viscosity of 0.3
Pas, and an inherent viscosity of 0.27.
[0189] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0190] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 13
[0191] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.37 g (0.178 mol)
of t-CHDA, and 42.87 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.63 g (0.178 mol) of c-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.2 wt %, a solution viscosity of 0.4
Pas, and an inherent viscosity of 0.18.
[0192] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0193] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 14
[0194] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 20.63 g (0.178 mol)
of HMD, and 42.67 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.37 g (0.178 mol) of c-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.2 wt %, a solution viscosity of 0.5
Pas, and an inherent viscosity of 0.18.
[0195] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0196] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 15
[0197] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 16.76 g (0.190 mol)
of DAB, and 45.70 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 58.24 g (0.190 mol) of c-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.3 wt %, a solution viscosity of 0.2
Pas, and an inherent viscosity of 0.19.
[0198] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0199] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 16
[0200] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 14.61 g (0.197 mol)
of DAP, and 47.39 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 60.39 g (0.197 mol) of c-DCDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 12.0 wt %, a solution viscosity of 0.1
Pas, and an inherent viscosity of 0.17.
[0201] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0202] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-2.
Example 17
[0203] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 8.64 g (0.043 mol) of
ODA and 15.05 g (0.129 mol) of HMD, and 41.49 g (1.25 equivalents
per carboxyl group) of 1,2-DMZ were added thereto, and the mixture
was stirred at 25.degree. C. for 1 hour to dissolve these compounds
in water. Subsequently, 38.09 g (0.129 mol) of s-BPDA and 13.22 g
(0.043 mol) of t-DCDA were added to the resulting solution, and the
mixture was stirred at 70.degree. C. for 6 hours to provide an
aqueous polyimide precursor solution having a solid content of 12.1
wt %, a solution viscosity of 1.2 Pas, and an inherent viscosity of
0.49.
[0204] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0205] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-3.
Example 18
[0206] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 425 g of water as a solvent. And then, 19.24 g (0.096 mol)
of ODA and 3.66 g (0.032 mol) of t-CHDA, and 30.79 g (1.25
equivalents per carboxyl group) of 1,2-DMZ were added thereto, and
the mixture was stirred at 25.degree. C. for 1 hour to dissolve
these compounds in water. Subsequently, 9.42 g (0.032 mol) of
s-BPDA and 42.68 g (0.096 mol) of 6FDA were added to the resulting
solution, and the mixture was stirred at 70.degree. C. for 6 hours
to provide an aqueous polyimide precursor solution having a solid
content of 13.4 wt %, a solution viscosity of 4.5 Pas, and an
inherent viscosity of 0.22.
[0207] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0208] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-3.
Example 19
[0209] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 9.37 g (0.047 mol) of
ODA and 21.76 g (0.187 mol) of HMD, and 56.26 g (1.25 equivalents
per carboxyl group) of 1,2-DMZ were added thereto, and the mixture
was stirred at 25.degree. C. for 1 hour to dissolve these compounds
in water. Subsequently, 68.87 g (0.234 mol) of s-BPDA was added to
the resulting solution, and the mixture was stirred at 70.degree.
C. for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 16.0 wt %, a solution viscosity of 0.7
Pas, and an inherent viscosity of 0.72.
[0210] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0211] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-3.
Example 20
[0212] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 5.29 g (0.049 mol) of
PPD and 22.74 g (0.196 mol) of HMD, and 58.80 g (1.25 equivalents
per carboxyl group) of 1,2-DMZ were added thereto, and the mixture
was stirred at 25.degree. C. for 1 hour to dissolve these compounds
in water. Subsequently, 71.97 g (0.245 mol) of s-BPDA was added to
the resulting solution, and the mixture was stirred at 70.degree.
C. for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 15.7 wt %, a solution viscosity of 1.4
Pas, and an inherent viscosity of 0.86.
[0213] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0214] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 1-3.
Reference Example 1
[0215] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 450 g of water as a solvent. And then, 20.25 g (0.101 mol)
of ODA, and 24.31 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 29.75 g (0.101 mol) of s-BPDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 8.7 wt %, a solution viscosity of 32.0
Pas, and an inherent viscosity of 0.42.
[0216] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0217] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 2
[0218] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 450 g of water as a solvent. And then, 13.44 g (0.124 mol)
of PPD, and 29.87 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 36.56 g (0.124 mol) of s-BPDA was added to the
resulting solution, and the mixture was stirred at 70.degree. C.
for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 9.1 wt %, a solution viscosity of 63.0
Pas, and an inherent viscosity of 1.86.
[0219] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0220] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 3
[0221] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 450 g of water as a solvent. And then, 11.16 g (0.056 mol)
of ODA and 6.03 g (0.056 mol) of PPD, and 26.80 g (1.25 equivalents
per carboxyl group) of 1,2-DMZ were added thereto, and the mixture
was stirred at 25.degree. C. for 1 hour to dissolve these compounds
in water. Subsequently, 32.81 g (0.112 mol) of s-BPDA was added to
the resulting solution, and the mixture was stirred at 70.degree.
C. for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 8.7 wt %, a solution viscosity of 52.2
Pas, and an inherent viscosity of 0.54.
[0222] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0223] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 4
[0224] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 16.03 g (0.148 mol)
of PPD and 11.29 g (0.099 mol) of t-CHDA, and 59.38 g (1.25
equivalents per carboxyl group) of 1,2-DMZ were added thereto, and
the mixture was stirred at 25.degree. C. for 1 hour to dissolve
these compounds in water. Subsequently, 72.68 g (0.247 mol) of
s-BPDA was added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours to provide an aqueous
polyimide precursor solution having a solid content of 16.7 wt %, a
solution viscosity of 27.2 Pas, and an inherent viscosity of
1.04.
[0225] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0226] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 5
[0227] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 18.70 g (0.173 mol)
of PPD and 8.61 g (0.074 mol) of HMD, and 59.38 g (1.25 equivalents
per carboxyl group) of 1,2-DMZ were added thereto, and the mixture
was stirred at 25.degree. C. for 1 hour to dissolve these compounds
in water. Subsequently, 72.68 g (0.247 mol) of s-BPDA was added to
the resulting solution, and the mixture was stirred at 70.degree.
C. for 6 hours to provide an aqueous polyimide precursor solution
having a solid content of 16.1 wt %, a solution viscosity of 30.2
Pas, and an inherent viscosity of 0.82.
[0228] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0229] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 6
[0230] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 26.64 g (0.246 mol)
of PPD, and 59.20 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 50.73 g (0.172 mol) of s-BPDA and 22.63 g (0.074 mol)
of t-DCDA were added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours to provide an aqueous
polyimide precursor solution having a solid content of 16.2 wt %, a
solution viscosity of 107.5 Pas, and an inherent viscosity of
0.87.
[0231] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0232] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Reference Example 7
[0233] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 28.36 g (0.262 mol)
of PPD, and 63.03 g (1.25 equivalents per carboxyl group) of
1,2-DMZ were added thereto, and the mixture was stirred at
25.degree. C. for 1 hour to dissolve these compounds in water.
Subsequently, 54.00 g (0.184 mol) of s-BPDA and 17.63 g (0.079 mol)
of H-PMDA were added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours to provide an aqueous
polyimide precursor solution having a solid content of 16.5 wt %, a
solution viscosity of 8.7 Pas, and an inherent viscosity of
0.60.
[0234] The aqueous polyimide precursor solution composition
obtained was applied on a glass plate as a substrate with a bar
coater. The resulting coating film was deaerated and predried at
25.degree. C. for 30 minutes under reduced pressure. Subsequently,
the predried coating film was placed into a hot air dryer and
heated at 80.degree. C. for 30 minutes, 120.degree. C. for 30
minutes, 200.degree. C. for 10 minutes, and then 250.degree. C. for
10 minutes under atmospheric pressure, to provide a polyimide
substrate for flexible device having a thickness of 10 .mu.m.
[0235] The results of the state observations and the properties
evaluations of the aqueous polyimide precursor solution composition
and the polyimide substrate for flexible device obtained are shown
in Table 2.
Comparative Example 1
[0236] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 17.35 g (0.149 mol)
of HMD and 33.85 g (0.017 mol) of JEFFAMINE D2000, and 39.87 g
(1.25 equivalents per carboxyl group) of 1,2-DMZ were added
thereto, and the mixture was stirred at 25.degree. C. for 1 hour to
dissolve these compounds in water. Subsequently, 48.80 g (0.166
mol) of s-BPDA was added to the resulting solution, and the mixture
was stirred at 70.degree. C. for 6 hours. Still, s-BPDA was not
dissolved therein homogeneously, and an aqueous polyimide precursor
solution composition could not be obtained.
[0237] The results are shown in Table 3.
Comparative Example 2
[0238] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 23.06 g (0.198 mol)
of HMD and 12.07 g (0.022 mol) of PRIAMINE 1074, and 53.00 g (1.25
equivalents per carboxyl group) of 1,2-DMZ were added thereto, and
the mixture was stirred at 25.degree. C. for 1 hour to dissolve
these compounds in water. Subsequently, 64.87 g (0.220 mol) of
s-BPDA was added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours. Still, s-BPDA was not
dissolved therein homogeneously, and an aqueous polyimide precursor
solution composition could not be obtained.
[0239] The results are shown in Table 3.
Comparative Example 3
[0240] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 21.75 g (0.109 mol)
of ODA and 24.63 g (0.012 mol) of JEFFAMINE D2000, and 29.01 g
(1.25 equivalents per carboxyl group) of 1,2-DMZ were added
thereto, and the mixture was stirred at 25.degree. C. for 1 hour to
dissolve these compounds in water. Subsequently, 53.61 g (0.121
mol) of 6FDA was added to the resulting solution, and the mixture
was stirred at 70.degree. C. for 6 hours. Still, 6FDA was not
dissolved therein homogeneously, and an aqueous polyimide precursor
solution composition could not be obtained.
[0241] The results are shown in Table 3.
Comparative Example 4
[0242] In a 500 mL (internal volume) glass reaction vessel equipped
with a stirrer and a nitrogen-gas charging/discharging tube was
placed 400 g of water as a solvent. And then, 33.30 g (0.166 mol)
of ODA and 10.11 g (0.018 mol) of PRIAMINE 1074, and 44.41 g (1.25
equivalents per carboxyl group) of 1,2-DMZ were added thereto, and
the mixture was stirred at 25.degree. C. for 1 hour to dissolve
these compounds in water. Subsequently, 56.59 g (0.184 mol) of
c-DCDA was added to the resulting solution, and the mixture was
stirred at 70.degree. C. for 6 hours. Still, c-DCDA was not
dissolved therein homogeneously, and an aqueous polyimide precursor
solution composition could not be obtained.
[0243] The results are shown in Table 3.
TABLE-US-00001 TABLE 1-1 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 Example 7 Example 8 Composition of aqueous
polyimide precursor solution acid s-BPDA (mol %) 100 100 100 30
component ODPA (mol %) 100 6FDA (mol %) 100 100 100 t-DCDA (mol %)
c-DCDA (mol %) 70 diamine ODA (mol %) 100 component PPD (mol %) 100
t-CHDA (mol %) 100 100 100 100 HMD (mol %) 100 DAB (mol %) 100 DAP
(mol %) imidazole 1,2-DMZ (equivalents) 1.25 1.25 1.25 1.25 1.25
1.25 1.25 1.25 Aqueous polyimide precursor solution polymerization
temperature 70 70 70 70 70 70 70 70 polymerization time 6 6 6 6 6 6
6 6 inherent viscosity 0.72 0.63 0.45 0.27 0.43 0.13 0.62 0.40
solid content (wt %) 12.8 12.4 12.2 12.2 12.5 13.0 13.4 12.2
solution viscosity (Pa s) 1.2 0.7 0.3 0.1 0.1 2.5 4.5 0.1
Properties of polyimide state observation .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. light transmittance at
400 nm (%) 75 78 80 92 84 78 62 88 total light transmittance (%) 95
91 92 94 89 91 94 91
TABLE-US-00002 TABLE 1-2 Example Example Example Example Example
Example Example Example 9 10 11 12 13 14 15 16 Composition of
aqueous polyimide precursor solution acid s-BPDA (mol %) component
ODPA (mol %) 6FDA (mol %) t-DCDA (mol %) 100 100 100 100 c-DCDA
(mol %) 100 100 100 100 diamine ODA (mol %) component PPD (mol %)
t-CHDA (mol %) 100 100 HMD (mol %) 100 100 DAB (mol %) 100 100 DAP
(mol %) 100 100 imidazole 1,2-DMZ (equivalents) 1.25 1.25 1.25 1.25
1.25 1.25 1.25 1.25 Aqueous polyimide precursor solution
polymerization temperature 70 70 70 70 70 70 70 70 polymerization
time 6 6 6 6 6 6 6 6 inherent viscosity 0.20 0.25 0.25 0.27 0.18
0.18 0.19 0.17 solid content (wt %) 12.4 12.2 12.3 12.0 12.2 12.2
12.3 12.0 solution viscosity (Pa s) 0.5 0.6 0.4 0.3 0.4 0.5 0.2 0.1
Properties of polyimide state observation .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. light transmittance at 84
88 90 89 84 85 87 88 400 nm (%) total light transmittance (%) 89 90
92 92 91 92 92 91
TABLE-US-00003 TABLE 1-3 Example 17 Example 18 Example 19 Example
20 Composition of aqueous polyimide precursor solution acid s-BPDA
(mol %) 75 25 100 100 component ODPA (mol %) 6FDA (mol %) 75 t-DCDA
(mol %) 25 c-DCDA (mol %) diamine ODA (mol %) 25 75 20 component
PPD (mol %) 20 t-CHDA (mol %) 25 HMD (mol %) 75 80 80 DAB (mol %)
DAP (mol %) imidazole 1,2-DMZ (equivalents) 1.25 1.25 1.25 1.25
Aqueous polyimide precursor solution polymerization temperature 70
70 70 70 polymerization time 6 6 6 6 inherent viscosity 0.49 0.22
0.72 0.86 solid content (wt %) 12.1 13.4 16.0 15.7 solution
viscosity (Pa s) 1.2 4.5 0.7 1.4 Properties of polyimide state
observation .largecircle. .largecircle. .largecircle. .largecircle.
light transmittance at 400 nm (%) 75 75 75 70 total light
transmittance (%) 88 93 92 93
TABLE-US-00004 TABLE 2 Reference Reference Reference Reference
Reference Reference Reference Example 1 Example 2 Example 3 Example
4 Example 5 Example 6 Example 7 Composition of aqueous polyimide
precursor solution acid s-BPDA (mol %) 100 100 100 100 100 70 70
component c-DCDA (mol %) t-DCDA (mol %) 30 H-PMDA (mol %) 30
diamine ODA (mol %) 100 50 component PPD (mol %) 100 50 60 70 100
100 t-CHDA (mol %) 40 HMD (mol %) 30 imidazole 1,2-DMZ
(equivalents) 1.25 1.25 1.25 1.25 1.25 1.25 1.25 Aqueous polyimide
precursor solution polymerization temperature 70 70 70 70 70 70 70
polymerization time 6 6 6 6 6 6 6 inherent viscosity 0.42 1.86 0.54
1.04 0.82 0.87 0.60 solid content (wt %) 8.7 9.1 8.7 16.7 16.1 16.2
16.5 solution viscosity (Pa s) 32.0 63.0 52.2 27.2 30.2 107.5 8.7
Properties of polyimide state observation .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. light transmittance at 400 nm (%) 6 5 5
22 31 12 15 total light transmittance (%) 78 75 76 85 87 78 80
TABLE-US-00005 TABLE 3 Comparative Comparative Comparative
Comparative Example 1 Example 2 Example 3 Example 4 Composition of
aqueous polyimide precursor solution acid s-BPDA (mol %) 100 100
component 6FDA (mol %) 100 c-DCDA (mol %) 100 diamine ODA (mol %)
90 90 component HMD (mol %) 90 90 D2000 (mol %) 10 10 1074 (mol %)
10 10 imidazole 1,2-DMZ (equivalents) 1.25 1.25 1.25 1.25 Aqueous
polyimide precursor solution polymerization temperature 70 70 70 70
polymerization time 6 6 6 6 inherent viscosity Aqueous polyimide
precursor solution solid content (wt %) could not be obtained.
solution viscosity (Pa s) (not homogeneously dissolved)
INDUSTRIAL APPLICABILITY
[0244] According to the present invention, there may be provided a
method for easily producing an aqueous polyimide precursor solution
composition, which has higher environmental acceptability, without
the need for a solvent other than water. According to the
production method, an aqueous polyimide precursor solution
composition having an extremely low organic solvent content,
particularly an aqueous polyimide precursor solution composition
comprising an aqueous solvent which contains no organic solvent,
may be very easily (directly) produced.
[0245] According to the present invention, there may be provided an
aqueous polyimide precursor solution composition which comprises an
aqueous solvent and has good environmental acceptability, and may
provide a polyimide having high transparency, and having excellent
properties such as flexibility, heat resistance, electrical
properties, and solvent resistance, and preferably comprises a
solvent containing no organic solvent other than water. The
polyimide obtained by heating the aqueous polyimide precursor
solution composition of the present invention may be suitably used
for an electrical device, an electronic device, an optical device,
or the like, and may be suitably used, for example, as a substrate,
or a protective film for a display device such as a liquid crystal
display, an EL display and an electronic paper, a touch panel, a
solar battery, or an LED lighting device, or the like. The
polyimide may be particularly suitably used as a substrate of a
flexible device, for example, a display device such as a liquid
crystal display, an organic EL display and an electronic paper, and
a light-receiving device such as a light-receiving element of a
thin-film solar battery.
[0246] According to the present invention, there may be also
provided a polyimide precursor resin composition for flexible
device substrates, which comprises an aqueous solvent and has good
environmental acceptability. Moreover, the polyimide substrate for
flexible device which is obtained according to the present
invention may have high transparency, and have excellent properties
such as flexibility, heat resistance, electrical properties, and
solvent resistance, and therefore may be suitably used, for
example, as a substrate for flexible device which is a display
device such as substrates for a liquid crystal display, an organic
EL display and an electronic paper, and as a substrate for flexible
device which is a light-receiving device such as a substrate for a
thin-film solar battery.
* * * * *