U.S. patent application number 09/893540 was filed with the patent office on 2001-12-13 for fluorine-containing polymer composition.
This patent application is currently assigned to ASAHI GLASS COMPANY LTD.. Invention is credited to Matsukura, Ikuo, Shirota, Naoko.
Application Number | 20010051700 09/893540 |
Document ID | / |
Family ID | 27341324 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010051700 |
Kind Code |
A1 |
Matsukura, Ikuo ; et
al. |
December 13, 2001 |
Fluorine-containing polymer composition
Abstract
A fluorine-containing polymer composition comprising a
fluorine-containing solvent of the formula R.sup.1--O--R.sup.2
wherein R.sup.1 is a C.sub.5-12 linear or branched polyfluoroalkyl
group which may have an ether bond, and R.sup.2 is a C.sub.1-5
linear or branched alkyl group, and a fluorine-containing amorphous
polymer having a fluorine-containing ring structure in its main
chain, dissolved in the solvent.
Inventors: |
Matsukura, Ikuo;
(Yokohama-shi, JP) ; Shirota, Naoko;
(Yokohama-shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
ASAHI GLASS COMPANY LTD.
Chiyoda-ku
JP
100-8305
|
Family ID: |
27341324 |
Appl. No.: |
09/893540 |
Filed: |
June 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09893540 |
Jun 29, 2001 |
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09662863 |
Sep 15, 2000 |
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6284379 |
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09662863 |
Sep 15, 2000 |
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09209756 |
Dec 11, 1998 |
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6201085 |
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Current U.S.
Class: |
526/247 ;
526/242; 526/248; 526/249; 526/251; 526/253 |
Current CPC
Class: |
C08K 5/06 20130101; C09D
127/12 20130101; C08K 5/06 20130101; C08L 27/12 20130101; C08L
2666/28 20130101; C09D 127/12 20130101 |
Class at
Publication: |
526/247 ;
526/242; 526/248; 526/249; 526/251; 526/253 |
International
Class: |
C08F 116/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 1997 |
JP |
9-349718 |
Claims
What is claimed is:
1. A fluorine-containing polymer composition comprising a
fluorine-containing solvent of the formula R.sup.1--O--R.sup.2
wherein R.sup.1 is a C.sub.5-12 linear or branched polyfluoroalkyl
group which may have an ether bond, and R.sup.2 is a C.sub.1-5
linear or branched alkyl group, and a fluorine-containing amorphous
polymer having a fluorine-containing ring structure in its main
chain, dissolved in the solvent.
2. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing ring structure is a
fluorine-containing alicyclic structure, a fluorine-containing
triazine ring structure or a fluorine-containing aromatic ring
structure.
3. The fluorine-containing polymer composition according to claim
2, wherein the fluorine-containing alicyclic structure is a
fluorine-containing aliphatic ether ring structure.
4. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing amorphous polymer is one
obtained by polymerizing a monomer having a fluorine-containing
ring structure.
5. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing amorphous polymer is one
obtained by cyclic polymerization of a fluorine-containing monomer
having at least two polymerizable double bonds.
6. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing amorphous polymer is one
obtained by copolymerizing a monomer having a fluorine-containing
ring structure with a radical polymerizable monomer having no
fluorine-containing ring structure.
7. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing amorphous polymer is one
obtained by copolymerizing a fluorine-containing monomer having at
least two polymerizable double bonds and being cyclopolymerizable,
with a radical polymerizable monomer being not
cyclopolymerizable.
8. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing amorphous polymer is one
obtained by copolymerizing a monomer having a fluorine-containing
ring structure with a fluorine-containing monomer having at least
two polymerizable double bonds and being cyclopolymerizable.
9. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing solvent has a fluorine content
of from 60 to 80 wt %.
10. The fluorine-containing polymer composition according to claim
1, wherein the fluorine-containing solvent is
F(CF.sub.2).sub.6OCH.sub.3, F(CF.sub.2).sub.7OCH.sub.3,
F(CF.sub.2).sub.8OCH.sub.3, F(CF.sub.2).sub.9OCH.sub.3 or
F(CF.sub.2).sub.10OCH.sub.3.
11. The fluorine-containing polymer composition according to claim
1, wherein the concentration of the fluorine-containing amorphous
polymer in the fluorine-containing polymer composition is from 1.01
to 50 wt %.
12. A process for forming a thin film of a fluorine-containing
amorphous polymer on a substrate, which comprises coating on the
substrate a fluorine-containing polymer composition comprising a
fluorine-containing solvent of the formula R.sup.1--O--R.sup.2
wherein R.sup.1 is a C.sub.5-12 linear or branched polyfluoroalkyl
group which may have an ether bond, and R.sup.2 is a C.sub.1-5
linear or branched alkyl group, and a fluorine-containing amorphous
polymer having a fluorine-containing ring structure in its main
chain, dissolved in the solvent, and then drying the
fluorine-containing solvent.
13. The process according to claim 12, wherein the
fluorine-containing ring structure is a fluorine-containing
alicyclic structure, a fluorine-containing triazine ring structure
or a fluorine-containing aromatic ring structure.
14. The process according to claim 12, wherein the
fluorine-containing alicyclic structure is a fluorine-containing
aliphatic ether ring structure.
15. The process according to claim 12, wherein the thin film is an
antireflection film.
16. A process for obtaining a thin film of a fluorine-containing
amorphous polymer, which comprises coating on a substrate a
fluorine-containing polymer composition comprising a
fluorine-containing solvent of the formula R.sup.1--O--R wherein
R.sup.1 is a C.sub.5-12 linear or branched polyfluoroalkyl group
which may have an ether bond, and R.sup.2 is a C.sub.1-5 linear or
branched alkyl group, and a fluorine-containing amorphous polymer
having a fluorine-containing ring structure in its main chain,
dissolved in the solvent, then drying the fluorine-containing
solvent to form a thin film of the fluorine-containing amorphous
polymer on the substrate, and then peeling the thin film of the
fluorine-containing amorphous polymer from the substrate.
17. The process according to claim 16, wherein the
fluorine-containing ring structure is a fluorine-containing
alicyclic structure, a fluorine-containing triazine ring structure
or a fluorine-containing aromatic ring structure.
18. The process according to claim 16, wherein the
fluorine-containing alicyclic structure is a fluorine-containing
aliphatic ether ring structure.
19. The process according to claim 16, wherein the thin film is a
pellicle film.
Description
[0001] The present invention relates to a fluorine-containing
polymer composition comprising a specific fluorine-containing
solvent and a fluorine-containing amorphous polymer having a
fluorine-containing ring structure in its main chain, dissolved in
the solvent.
[0002] Perfluoro polymers represented by a polytetrafluoroethylene,
a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer and a
tetrafluoroethylene/hexafluoropropylene copolymer, usually have
excellent characteristics such that the heat resistance and
chemical resistance are high, and the refractive index and the
dielectric constant are small. However, these fluorine-containing
polymers are usually insoluble in solvents.
[0003] WO96/22356 discloses that an amorphous tetrafluoroethylene
copolymer is dissolved or dispersed in a solvent such as
C.sub.5F.sub.11OCH.sub.3, C.sub.5F.sub.11OC.sub.2H.sub.5 or
C.sub.8F.sub.17OCH.sub.3 to obtain a coating composition. However,
there is no Example wherein an amorphous tetrafluoroethylene
copolymer is actually dissolved in such a solvent, and it is
uncertain whether or not an amorphous tetrafluoroethylene copolymer
is in fact soluble in such a solvent.
[0004] Whereas, a fluorine-containing polymer having a
fluorine-containing alicyclic structure in its main chain, as
disclosed e.g. JP-B-8-22929, shows an amorphous nature, as the
crystallization of the polymer is hindered by the steric effect of
the ring structure. This fluorine-containing polymer is soluble in
a specific perfluoro solvent such as
perfluoro(2-butyltetrahydrofuran) even though it may be a perfluoro
polymer. Accordingly, there is a merit in that from a perfluoro
solvent solution of this fluorine-containing polymer, it is
possible to form a thin film of the fluorine-containing polymer
free from pinholes.
[0005] In recent years, with a view to global environmental
protection, particularly to protection of the ozone layer, use of
fluorochlorohydrocarbons has been banned, and from the viewpoint of
warming up of the earth, use and discharge of carbon dioxide gas or
perfluorohydrocarbons are desired to be restricted.
[0006] Especially perfluoro compounds such as perfluorohydrocarbons
are said to substantially contribute to warming up of the earth
because of their strong infrared ray absorbing abilities and their
remarkably long lives in the atmosphere. For example, the estimated
value for the life of perfluorohexane in the atmosphere is said to
be from a few hundreds to a few thousands years. Such a perfluoro
compound absorbs infrared rays over a long period of time and
stores the radiation heat from the earth, whereby the influence
over the warming up of the earth is believed to be substantial.
[0007] Under these circumstances, it is an object of the present
invention to provide a fluorine-containing polymer composition
having "a fluorine-containing amorphous polymer having a
fluorine-containing ring structure in its main chain" (hereinafter
referred to simply as a fluorine-containing ring
structure-containing polymer) dissolved in a solvent which has a
low contribution to warming up of the earth.
[0008] The present invention provides a fluorine-containing polymer
composition comprising a fluorine-containing solvent of the formula
R.sup.1--O--R wherein R.sup.1 is a C.sub.5-12 linear or branched
polyfluoroalkyl group which may have an ether bond, and R.sup.2 is
a C.sub.1-5 linear or branched alkyl group, and a
fluorine-containing polymer having a fluorine-containing ring
structure in its main chain, dissolved in the solvent.
[0009] In the present invention, the fluorine-containing solvent is
a fluorine-containing solvent of the formula R.sup.1--O--R wherein
R.sup.1 is a C.sub.5-12 linear or branched polyfluoroalkyl group
which may have an ether bond, and R.sup.2 is a C.sub.1-5 linear or
branched alkyl group.
[0010] If the carbon number of R.sup.1 is 4 or less, it tends to be
difficult to dissolve the fluorine-containing ring
structure-containing polymer, and if the carbon number of R.sup.1
is 13 or higher, such a solvent is hardly industrially available.
Accordingly, the carbon number of R.sup.1 is selected within a
range of from 5 to 12. The carbon number of R.sup.1 is preferably
from 6 to 10, more preferably from 6 to 7 or 9 to 10.
[0011] The polyfluoroalkyl group is a group having at least two
hydrogen atoms of an alkyl group substituted by fluorine atoms, and
it includes a perfluoroalkyl group having all hydrogen atoms of an
alkyl group substituted by fluorine atoms, and a group having at
least two hydrogen atoms of an alkyl group substituted by fluorine
atoms and having at least one hydrogen atom of the alkyl group
substituted by a halogen atom other than a fluorine atom. As the
halogen atom other than a fluorine atom, a chlorine atom is
preferred.
[0012] The polyfluoroalkyl group is preferably a group having at
least 60% in the number of hydrogen atoms of the corresponding
alkyl group substituted by fluorine atoms, more preferably a group
having at least 80% so substituted. A more preferred
polyfluoroalkyl group is a perfluoroalkyl group.
[0013] When R.sup.1 has an ether bond, the number of ether bonds in
R is usually from 1 to 3, more preferably 1 or 2, since if the
number of ether bonds is too much, the solubility will be
impaired.
[0014] If the carbon number of R.sup.2 is 6 or higher, the
solubility of the fluorine-containing ring structure-containing
polymer will be substantially impaired. A preferred example of
R.sup.2 is CH.sub.3 or C.sub.2H.sub.5.
[0015] The molecular weight of the fluorine-containing solvent is
preferably at most 1,000, since if it is too large, not only the
viscosity of the fluorine-containing polymer composition increases,
but also the solubility of the fluorine-containing ring
structure-containing polymer decreases. Further, in order to
increase the solubility of the fluorine-containing ring
structure-containing polymer, the fluorine content of the
fluorine-containing solvent is preferably from 60 to 80 wt %.
[0016] The following may, for example, be mentioned as preferred
fluorine-containing solvents.
[0017] F(CF.sub.2).sub.5OCH.sub.3,
[0018] F(CF.sub.2).sub.6OCH.sub.3,
[0019] F(CF.sub.2).sub.7OCH.sub.3,
[0020] F(CF.sub.2).sub.8OCH.sub.3,
[0021] F(CF.sub.2).sub.9OCH.sub.3,
[0022] F(CF.sub.2).sub.10OCH.sub.3,
[0023] H(CF.sub.2).sub.6OCH.sub.3,
[0024] (CF.sub.3).sub.2CF(OCH.sub.3)CFCF.sub.2CF.sub.3,
[0025] F(CF.sub.2).sub.3OCF(CF.sub.3)CF.sub.2OCH.sub.3,
[0026]
F(CF.sub.2).sub.3OCF(CF.sub.3)CF.sub.2OCF(CF.sub.3)CF.sub.2OCH.sub.-
3,
[0027] F(CF2).sub.8OCH.sub.2CH.sub.2CH.sub.3,
[0028] (CF.sub.3).sub.2CFCF.sub.2CF.sub.2OCH.sub.3,
[0029] F(CF.sub.2).sub.2O(CF.sub.2).sub.4OCH.sub.2CH.sub.3.
[0030] As an example, the estimated life in the atmosphere of the
fluorine-containing solvent in the present invention is from about
1 to 5 years in the case of F(CF.sub.2).sub.5OCH.sub.3 and
F(CF.sub.2).sub.5OCH.sub.2CH.sub.3. As the fluorine-containing
solvent in the present invention, F(CF.sub.2).sub.6OCH.sub.3,
F(CF.sub.2).sub.7OCH.sub.3, F(CF.sub.2).sub.8OCH.sub.3,
F(CF.sub.2).sub.9OCH.sub.3 and F(CF.sub.2).sub.10OCH.sub.3 are
preferred, F(CF.sub.2).sub.6OCH.sub.3, F(CF.sub.2).sub.7OCH.sub.3,
F(CF.sub.2).sub.9OCH.sub.3 and F(CF.sub.2).sub.10OCH.sub.3 are
particularly preferred.
[0031] Such fluorine-containing solvents may be suitably used in
combination as a mixture of two or more of them. In a case of a
solvent mixture of a fluorine-containing solvent with other
solvent, such other solvent may be a solvent which is by itself
incapable of dissolving the fluorine-containing ring
structure-containing polymer.
[0032] As such other solvents, fluorine-containing ethers other
than the fluorine-containing solvent in the present invention, such
as F(CF.sub.2).sub.4OCH.sub.3 and F(CF.sub.2).sub.4OC.sub.2H.sub.5,
hydrocarbons such as hexane, hydrochlorocarbons such as chloroform,
hydrochlorofluorocarbons such as dichloropentafluoropropane,
fluorine-containing aromatic hydrocarbons such as m-xylene
hexafluoride and benzotrifluoride, and alcohols such as methanol,
ethanol, (perfluorohexyl)ethanol and pentafluoropropanol, may, for
example, be used in combination. The blend ratio of such other
solvents is suitably selected depending upon the concentration of
the fluorine-containing ring structure-containing polymer, but is
preferably from 0.1 to 50 parts by weight, more preferably from 1
to 30 parts by weight, per 100 parts by weight of the
fluorine-containing solvent.
[0033] In the present invention, the fluorine-containing ring
structure-containing polymer may, for example, be a
fluorine-containing polymer having a fluorine-containing alicyclic
structure (including a fluorine-containing imide ring structure), a
fluorine-containing triazine ring structure or a
fluorine-containing aromatic ring structure in its main chain.
Among them, a fluorine-containing polymer having a
fluorine-containing alicyclic structure in its main chain is
preferred, and particularly preferred is one having a
fluorine-containing aliphatic ether ring structure in its main
chain.
[0034] The term "having a fluorine-containing ring structure in its
main chain" is meant for having a structure wherein at least one
carbon atom constituting the ring is a carbon atom in the carbon
chain constituting the main chain and a fluorine atom or a
fluorine-containing group is bonded to at least a part of carbon
atoms constituting the ring.
[0035] The fluorine-containing polymer having a fluorine-containing
alicyclic structure in its main chain is preferably one obtained by
polymerizing a monomer having a fluorine-containing ring structure
or a polymer having a fluorine-containing alicyclic structure in
its main chain, obtained by cyclic polymerization of a
fluorine-containing monomer having at least two polymerizable
double bonds.
[0036] The polymer having a fluorine-containing alicyclic structure
in its main chain, obtained by polymerizing a monomer having a
fluorine-containing ring structure, is known, for example, by
JP-B-63-18964. Namely, the polymer having a fluorine-containing
alicyclic structure in its main chain, can be obtained by
homopolymerization of a monomer having a fluorine-containing ring
structure such as perfluoro(2,2-dimethyl-1,3-dioxole), or by
copolymerizing such a monomer with a radical polymerizable monomer
having no fluorine-containing ring structure, such as
tetrafluoroethylene, chlorotrifluoroethylene or perfluoro(methyl
vinyl ether). Whereas, the polymer having a fluorine-containing
alicyclic structure in its main chain, obtained by cyclic
polymerization of a fluorine-containing monomer having at least two
polymerizable double bonds, is known, for example, by
JP-A-63-238111 or JP-A-63-238115. Namely, the polymer having a
fluorine-containing alicyclic structure in its main chain can be
obtained by cyclic polymerization of a fluorine-containing monomer
having at least two polymerizable double bonds and being
cyclopolymerizable, such as perfluoro(allyl vinyl ether) or
perfluoro(butenyl vinyl ether), or by copolymerizing such a monomer
with a radical polymerizable monomer which is not
cyclopolymerizable, such as tetrafluoroethylene,
chlorotrifluoroethylene or perfluoro(methyl vinyl ether).
[0037] Further, the polymer having a fluorine-containing alicyclic
structure in its main chain can be obtained also by copolymerizing
a monomer having a fluorine-containing ring structure such as
perfluoro(2,2-dimethyl-1,3-dioxole) with a fluorine-containing
monomer having at least two polymerizable double bonds and being
cyclopolymerizable, such as perfluoro(allyl vinyl ether) or
perfluoro(butenyl vinyl ether).
[0038] The polymer having a fluorine-containing alicyclic structure
in its main chain is preferably one containing at least 20 mol %,
preferably at least 40 mol %, of polymer units having a
fluorine-containing alicyclic structure in its main chain, based on
the total polymer units of the polymer having a fluorine-containing
alicyclic structure in its main chain, from the viewpoint of
transparency or mechanical properties.
[0039] Specifically, one having repeating units selected from the
following formulae (1) to (4), is preferred as such a polymer
having a fluorine-containing alicyclic structure in its main chain.
Fluorine atoms in such a polymer having a fluorine-containing
alicyclic structure in its main chain may partly be substituted by
chlorine atoms. 1
[0040] In the formulae (1) to (4), h is an integer of from 0 to 5,
i is an integer of from 0 to 4, j is 0 or 1, h+i+j is an integer of
from 1 to 6, s is an integer of from 0 to 5, t is an integer of
from 0 to 4, u is 0 or 1, s+t+u is an integer of from 1 to 6, each
of p, q and r which are independent of one another, is an integer
of from 0 to 5, p+q+r is an integer of from 1 to 6, and each of
R.sup.3 to R.sup.8 which are independent of one another, is F, Cl,
D (deuterium) or CF.sub.3.
[0041] In the present invention, the monomer having a
fluorine-containing ring structure is preferably a monomer selected
from compounds of the following formulae (5) to (7): 2
[0042] In the formulae (5) to (7), each of R.sup.9 to R.sup.20
which are independent of one another, is F, Cl, D or CF.sub.3,
provided that R.sup.11 and R.sup.12, R.sup.15 and R.sup.16, or
R.sup.19 and R.sup.20, may be connected to form a ring.
[0043] As specific examples of the compounds of the formulae (5) to
(7), compounds of the formulae (11) to (18) may, for example, be
mentioned. 3
[0044] As the fluorine-containing monomer having at least two
polymerizable double bonds, compounds of the following formulae (8)
to(10) are preferred.
CY.sup.1Y.sup.2.dbd.CY.sup.3OCY.sup.4Y.sup.5CY.sup.6Y.sup.7CY.sup.8.dbd.CY-
.sup.9Y.sup.10 (8)
CZ.sup.1Z.sup.2.dbd.CZ.sup.3OCZ.sup.4Z.sup.5CZ.sup.6.dbd.CZ.sup.7Z.sup.8
(9)
CW.sup.1W.sup.2.dbd.CW.sup.3OCW.sup.4W.sup.5OCW.sup.6.dbd.CW.sup.7W.sup.8
(10)
[0045]
[0046] In the formulae (8) to (10), each of Y.sup.1 to Y.sup.10,
Z.sup.1 to Z.sup.8 and W.sup.1 to W.sup.8 which are independent of
one another, is F, Cl, D or CF.sub.3.
[0047] As specific examples of the compounds of the formulae (8) to
(10), the following compounds may be mentioned:
[0048] CF.sub.2.dbd.CFOCF.sub.2CF.sub.2CF.dbd.CF.sub.2,
[0049] CF.sub.2.dbd.CFOCD.sub.2CF.sub.2CF.dbd.CF.sub.2,
[0050] CF.sub.2.dbd.CFOCCl.sub.2CF.sub.2CF.dbd.CF.sub.2,
[0051] CF.sub.2.dbd.CFOCF.sub.2CF.sub.2CF.dbd.CF.sub.2,
[0052] CF.sub.2.dbd.CFOCF.sub.2CF.sub.2CCl.dbd.CF.sub.2,
[0053] CF.sub.2.dbd.CFOCF.sub.2CFDCF.dbd.CF.sub.2,
[0054] CF.sub.2.dbd.CFOCF.sub.2CFClCF.dbd.CF.sub.2,
[0055] CF.sub.2.dbd.CFOCF.sub.2CF(CF.sub.3)CF.dbd.CF.sub.2,
[0056] CF.sub.2.dbd.CFOCF.sub.2CF(CF.sub.3)CD.dbd.CF.sub.2,
[0057] CF.sub.2.dbd.CFOCF.sub.2CF(CF.sub.3)CCl.dbd.CF.sub.2,
[0058] CF.sub.2.dbd.CFOCF.sub.2CF.dbd.CF.sub.2,
[0059] CF.sub.2.dbd.CFOCF(CF.sub.3)CF.dbd.CF.sub.2,
[0060] CF.sub.2.dbd.CFOCF.sub.2OCF.dbd.CF.sub.2,
[0061] CF.sub.2.dbd.CDOCF.sub.2OCD.dbd.CF.sub.2,
[0062] CF.sub.2.dbd.CClOCF.sub.2OCCl.dbd.CF.sub.2,
[0063] CF.sub.2.dbd.CFOCD.sub.2OCF.dbd.CF.sub.2,
[0064] CF.sub.2.dbd.CFOCCl.sub.2OCF.dbd.CF.sub.2,
[0065] CF.sub.2.dbd.CFOC(CF.sub.3).sub.2OCF.dbd.CF.sub.2.
[0066] The concentration of the fluorine-containing polymer in the
fluorine-containing polymer composition of the present invention is
preferably from 0.01 to 50 wt %, more preferably from 0.1 to 20 wt
%.
[0067] A thin film of the fluorine-containing ring
structure-containing polymer can be formed on a substrate by
coating on the substrate the fluorine-containing polymer
composition of the present invention having the fluorine-containing
ring structure-containing polymer dissolved in the
fluorine-containing solvent and then drying the fluorine-containing
solvent. The thickness of the thin film is selected usually within
a range of from 0.01 to 50 .mu.m. The thin film may be applied to a
substrate of any shape or of any material. When the thin film is an
antireflection film, the substrate is preferably polymethyl
methacrylate, polycarbonate, polyethylene terephthalate or the
like. The temperature for drying the fluorine-containing solvent is
optionally selected depending upon the heat resistance of the
substrate, but it is usually preferably from 50 to 150.degree. C.,
more preferably from 70 to 120.degree. C. To prevent an irregular
film thickness, it is preferred to form the thin film in an
antistatic atmosphere.
[0068] A thin film of the fluorine-containing ring
structure-containing polymer can be obtained by coating on a
substrate the fluorine-containing polymer composition of the
present invention having the fluorine-containing ring
structure-containing polymer dissolved in the fluorine-containing
solvent, then drying the fluorine-containing solvent to form a thin
film of the fluorine-containing ring structure-containing polymer
on the substrate, and then peeling the thin film of the
fluorine-containing ring structure-containing polymer from the
substrate. The thickness of the thin film is selected usually
within a range of from 0.01 to 50 .mu.m. As the substrate, glass is
preferred, since the heat resistance temperature is high, and the
thin film can easily be peeled from the substrate. The temperature
for drying the fluorine-containing solvent is optionally selected
depending upon the heat resistance of the substrate, but it is
preferably at least the boiling point of the fluorine-containing
solvent. The temperature for drying is preferably from 50 to
200.degree. C., more preferably from 70 to 150.degree. C. To
prevent an irregular film thickness, it is preferred to form the
thin film in an antistatic atmosphere. Peeling of the thin film
from the substrate is preferably carried out in a polar solvent
which does not dissolve the fluorine-containing ring
structure-containing polymer, particularly preferably in water.
[0069] When a thin film having a thickness of at most 0.1 .mu.m is
to be formed, the above-mentioned fluorine-containing solvent of
the formula R.sup.1--O--R.sup.2 is preferably one wherein R is a
C.sub.6-7 polyfluoroalkyl group, since a uniform thin film with
little thickness deviation can be obtained.
[0070] When a thin film having a thickness of at least 1 .mu.m is
to be formed, the above-mentioned fluorine-containing solvent of
the formula R.sup.1--O--R.sup.2 is preferably one wherein R.sup.1
is a C.sub.9-12 polyfluoroalkyl group, since a uniform thin film
with little thickness deviation can be obtained.
[0071] As a method for forming the thin film, a roll coating
method, a casting method, a dipping method, a spin coating method,
a casting on water method, a die coating method or Langmuir
Blodgett method may, for example, be mentioned.
[0072] In order to improve the adhesion of the fluorine-containing
polymer to the substrate, a coupling agent of e.g. silane type,
epoxy type, titanium type or aluminum type may be incorporated
together with a fluorine-containing alcohol to the
fluorine-containing polymer composition, or an oligomer or the
like, of a silane coupling agent, may be incorporated.
[0073] The obtained thin film may be used as it is adhered to the
substrate or after peeling it from the substrate. As an application
of the thin film, a protective coat in the optical field or in the
electrical field may be mentioned. In such a case, as the
substrate, a magnetic disc substrate, an optical fiber, a mirror, a
solar cell, an optical disc, a touch panel, a photosensitive and
fixing drum, a film capacitor or various films for glass windows,
may, for example, be mentioned.
[0074] Further, the thin film can be used for a coating type
photoconductive material, a coating material of electric wires, an
ink repellent (for example for coating, or for a printing equipment
such as an ink jet printer), a lens material, an adhesive for
semiconductor elements (for example, an adhesive for a LOC (lead on
chip) tape, an adhesive for a diebond or an adhesive for fixing a
pellicle film), a protective coat for semiconductors (for example,
a buffer coat film, a passivation film, an .alpha.-ray shielding
film for semiconductor elements or a moisture preventive coating
agent), an interlayer dielectrics (for example, for semiconductor
elements, for liquid crystal display devices or for multilayered
circuit boards), an optical thin film (a pellicle film (for KrF
excimer laser or ArF excimer laser), an antireflection film for
display devices or an antireflection film for resists).
[0075] By using the fluorine-containing polymer composition of the
present invention, a thin film can be formed without impairing the
characteristics of the fluorine-containing ring
structure-containing polymer, such that it is free from defects
such as pinholes and it is transparent with low refractive index
and excellent in heat resistance and chemical resistance.
[0076] Now, the present invention will be described in further
detail with reference to Examples. However, it should be understood
that the present invention is by no means restricted to such
specific Examples.
EXAMPLE 1
[0077] Preparation of a Fluorine-containing Ring
Structure-containing Polymer
[0078] 35 g of perfluoro(butenyl vinyl ether), 150 g of deionized
water, 6 g of methanol as a molecular weight regulating agent and
90 mg of ((CH.sub.3).sub.2CHOCOO).sub.2 as a polymerization
initiator, were introduced into a pressure resistant glass
autoclave having an internal capacity of 200 ml. The interior of
the system was replaced three times with nitrogen, and then
suspension polymerization was carried out at 40.degree. C. for 22
hours to obtain an amorphous polymer having terminal groups
attributable to the initiator. This polymer was subjected to heat
treatment in air at 320.degree. C. for 60 minutes, then washed with
water and dried. As a result, a fluorine-containing ring
structure-containing polymer having the above-mentioned terminal
groups converted to carboxyl groups (hereinafter referred to as
polymer A) was obtained in an amount of 33 g.
[0079] From the infrared spectrum analysis of polymer A, absorption
peaks attributable to carboxyl groups were confirmed at 1,811
cm.sup.-1 and 1,773 cm.sup.-1. The specific viscosity [.eta.] of
polymer A was 0.35 at 30.degree. C. in
perfluoro(2-butyltetrahydrofuran). The glass transition temperature
of polymer A was 108.degree. C., and it was a polymer which was
tough, transparent and glassy at room temperature. Further, the 10%
thermal decomposition temperature was 465.degree. C., and the light
transmittance was as high as at least 95%.
EXAMPLE 2
[0080] Preparation of a Fluorine-containing Ring
Structure-containing Polymer
[0081] 35 g of perfluoro(butenyl vinyl ether), 150 g of deionized
water, 6 g of methanol as a molecular weight regulating agent and
90 mg of ((CH.sub.3).sub.2CHOCOO).sub.2 as a polymerization
initiator, were introduced into a pressure resistant glass
autoclave having an internal capacity of 200 ml. The interior of
the system was replaced three times with nitrogen, and then
suspension polymerization was carried out at 40.degree. C. for 22
hours to obtain 28 g of a fluorine-containing ring
structure-containing polymer (hereinafter referred to as polymer
B).
[0082] The specific viscosity [.eta.] of polymer B was 0.35 at
30.degree. C. in perfluoro(2-butyltetrahydrofuran). The glass
transition point of polymer B was 108.degree. C., and it was a
polymer which was tough, transparent and amorphous at room
temperature. Further, the 10% thermal decomposition temperature was
465.degree. C. The light transmittance was as high as at least 95%,
and the refractive index was as low as 1.34.
EXAMPLE 3 (COMPARATIVE EXAMPLE)
[0083] 1 g of polymer A and 99 g of F(CF.sub.2).sub.3OCH.sub.3 were
put into a glass flask and stirred under heating at 30.degree. C.
for 24 hours. As a result, polymer A was not dissolved although it
swelled.
EXAMPLE 4 (COMPARATIVE EXAMPLE)
[0084] 1 g of polymer A and 99 g of F(CF.sub.2).sub.4OCH.sub.3 were
put into a glass flask and stirred under heating at 40.degree. C.
for 24 hours. As a result, polymer A was partially dissolved, but
was not completely dissolved, and swelled polymer A remained.
EXAMPLE 5 (PRESENT INVENTION)
[0085] 1 g of polymer A and 99 g of F(CF.sub.2).sub.6OCH.sub.3 were
put into a glass flask and stirred under heating at 40.degree. C.
for 24 hours. As a result, a colorless transparent uniform solution
free from turbidity was obtained. Using this solution, a
polymethylacrylate plate having an average reflectance of 4% on one
side was subjected to dip coating at a withdrawing speed of 200
mm/min and then subjected to heat treatment at 80.degree. C. for 1
hour, whereby a uniform transparent film of 0.1 .mu.m was obtained
on the acrylic plate. The film thickness deviation of this film was
less than 1%. The average reflectance on one side of this
polymethylacrylate plate was 1.0%. This polymethylacrylate plate
can be used as a low reflection filter.
EXAMPLE 6 (PRESENT INVENTION)
[0086] 1 g of polymer A and 99 g of F(CF.sub.2).sub.8OCH.sub.3 were
put into a glass flask and stirred under heating at 40.degree. C.
for 24 hours. As a result, a colorless transparent uniform solution
free from turbidity was obtained. By using this solution, a
polymethylacrylate plate having an average reflectance of 4% on one
side was subjected to dip coating at a withdrawing speed of 200
mm/min and then subjected to heat treatment at 80.degree. C. for 1
hour, whereby a transparent film of 0.1 .mu.m was obtained on the
polymethylacrylate plate. The film thickness deviation of this film
was 5%. The average reflectance on one side of this
polymethylacrylate plate was 1.0%.
EXAMPLE 7 (PRESENT INVENTION)
[0087] 9 g of polymer B and 91 g of F(CF.sub.2).sub.10OCH.sub.3
were put into a glass flask and stirred under heating at 50.degree.
C. for 24 hours. As a result, a colorless transparent uniform
solution free from turbidity was obtained. Using this solution,
spin coating was carried out on a glass plate at a spinning speed
of 700 rpm for 30 seconds and then subjected to heat treatment at
80.degree. C. for 1 hour and then at 180.degree. C. for further 1
hour, whereby a uniform transparent film was obtained on the glass
plate. Thereafter, an aluminum frame having an adhesive coated, was
bonded to the film, and this film was peeled from the glass plate,
whereby an aluminum frame provided with a self-standing film of
uniform polymer B having a film thickness of 1 .mu.m was obtained.
The film thickness deviation of this film was less than 1%. This
frame can be used as a pellicle.
EXAMPLE 8 (PRESENT INVENTION)
[0088] 9 g of polymer B and 91 g of F(CF.sub.2).sub.8OCH.sub.3 were
put into a glass flask and stirred under heating at 50.degree. C.
for 24 hours. As a result, a colorless transparent uniform solution
free from turbidity was obtained. Using this solution, spin coating
was carried out on a glass plate at a spinning speed of 700 rpm for
30 seconds, and then heat treatment was carried out at 80.degree.
C. for 1 hour and at 180.degree. C. for further 1 hour, whereby a
uniform transparent film was obtained on the glass plate. The film
thickness deviation of this film was 6%.
EXAMPLE 9 (PRESENT INVENTION)
[0089] Using the solution of polymer A obtained in Example 7, spin
coating was carried out on a metal substrate at a spinning speed of
700 rpm for 30 seconds, and then heat treatment was carried out at
80.degree. C. for 1 hour and at 180.degree. C. for further 1 hour,
whereby a uniform transparent film of 1 .mu.m was obtained on the
metal plate. This film was free from pinholes, which was confirmed
by the fact that the electric resistance of this thin film was at
least 10.sup.15 .OMEGA.cm.
EXAMPLE 10 (PRESENT INVENTION)
[0090] A polymethylacrylate plate having a uniform thin film of 0.1
.mu.m was obtained in the same manner as in Example 5 except that
instead of polymer B, 9 g of a perf luoro(2,2-dimethyl-1,
3-dioxolane)/tetrafluoroet- hylene (65 mol %/35 mol %) amorphous
copolymer (Teflon AF1600, tradename, manufactured by Du Pont) was
used, and instead of F(CF.sub.2).sub.6OCH.su- b.3, 91 g of
(CF.sub.3).sub.2CF(OCH.sub.3)CFCF.sub.2CF.sub.3 was used. The film
thickness deviation of this film was less than 1%. The average
reflectance on one side of this polymethylacrylate plate was
1.0%.
[0091] According to the present invention, the fluorine-containing
ring structure-containing polymer can be dissolved by means of a
solvent which is little influential over the global environment,
particularly over warming up of the earth, and a thin film of the
fluorine-containing ring-structure-containing polymer can be formed
while suppressing the adverse effects to the global
environment.
* * * * *