U.S. patent application number 10/564056 was filed with the patent office on 2006-07-27 for coating composition, coating film made of same, and optical article.
Invention is credited to Masahiro Johno, Hiroyuki Okada, Motoharu Takeuchi.
Application Number | 20060167217 10/564056 |
Document ID | / |
Family ID | 34106896 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060167217 |
Kind Code |
A1 |
Okada; Hiroyuki ; et
al. |
July 27, 2006 |
Coating composition, coating film made of same, and optical
article
Abstract
There is provided a coating composition having a good wetting
property which is capable of forming a coating film exhibiting a
high refractive index, a less discoloration, and excellent
transparency and uniformity when polymerized and cured. The present
invention relates to a coating composition comprising (A) 100 parts
by weight of a thiirane ring-containing compound, (B) 0.0001 to 10
parts by weight of a catalyst for accelerating polymerization of
the thiirane ring-containing compound, and (C) 0.005 to 4 parts by
weight of a modified silicone oil; a coating film produced from the
composition; and an optical product provided with the coating
film.
Inventors: |
Okada; Hiroyuki; (TOKYO,
JP) ; Takeuchi; Motoharu; (Tokyo, JP) ; Johno;
Masahiro; (Tokyo, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET
SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
34106896 |
Appl. No.: |
10/564056 |
Filed: |
July 21, 2004 |
PCT Filed: |
July 21, 2004 |
PCT NO: |
PCT/JP04/10688 |
371 Date: |
January 10, 2006 |
Current U.S.
Class: |
528/380 ;
106/154.11; 106/498; 106/499; 106/506; 549/90 |
Current CPC
Class: |
Y10T 428/31533 20150401;
C09D 181/02 20130101; B05D 3/0272 20130101; C08G 75/08 20130101;
Y10T 428/31663 20150401; G02B 1/10 20130101 |
Class at
Publication: |
528/380 ;
106/498; 106/499; 106/506; 106/154.11; 549/090 |
International
Class: |
C08K 5/00 20060101
C08K005/00; C09D 189/00 20060101 C09D189/00; C07D 409/02 20060101
C07D409/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2003 |
JP |
2003-279472 |
Aug 1, 2003 |
JP |
2003-285448 |
Claims
1. A coating composition comprising (A) 100 parts by weight of a
thiirane ring-containing compound, (B) 0.0001 to 10 parts by weight
of a catalyst for accelerating polymerization of the thiirane
ring-containing compound, and (C) 0.005 to 4 parts by weight of a
modified silicone oil.
2. The coating composition according to claim 1, further comprising
1 to 30 parts by weight of (D) a silane coupling agent.
3. The coating composition according to claim 1, wherein the
compound (C) have a surface-active property.
4. The coating composition according to claim 1, wherein the
compound (A) has at least one structure represented by the
following structural formula (1): ##STR6##
5. The coating composition according to claim 1, wherein the
compound (A) has a structure represented by the following
structural formula (2): ##STR7## wherein m is an integer of 0 to 4;
and n is an integer of 0 to 2.
6. A coating film obtained by polymerizing and curing the coating
composition as defined in claim 1.
7. An optical product provided on a surface thereof with the
coating film as defined in claim 6.
8. The coating composition according to claim 2, wherein the
compound (C) have a surface-active property.
9. A coating film obtained by polymerizing and curing the coating
composition as defined in claim 2.
10. An optical product provided on a surface thereof with the
coating film as defined in claim 9.
Description
TECHNICAL FIELD
[0001] The present invention relates to coating compositions used
for forming a coating film on a glass substrate, a quartz
substrate, a silicon substrate, a metal substrate, a plastic
substrate, a plastic film, etc., and more particularly to coating
compositions capable of forming a coating film having a high
refractive index, a less discoloration, and excellent transparency,
uniformity and adhesion property when polymerized and cured, which
are useful as coating materials for optical products applied to
various displays, etc.; coating films obtained by polymerizing and
curing the composition; and optical products provided on a surface
thereof with the coating film.
BACKGROUND ART
[0002] As typical transparent resins, there are known polymethyl
methacrylate (PMMA), polycarbonates (PC), polyethylene
terephthalate (PET), epoxy resins, polyethylene (PE), polypropylene
(PP) and the like. However, these resins have a refractive index of
about 1.60 at the maximum.
[0003] On the other hand, the present inventors have already found
the novel sulfur-containing compounds having an episulfide
structure, and have developed transparent resins having a
refractive index of 1.71 which is far higher than those of the
conventionally existing resins (refer to JP 9-71580A and JP
9-110979A). In these previous inventions made by the present
inventors, the sulfur-containing compounds having an episulfide
structure are cast into a so-called mold and then polymerized and
cured to obtain a cured product thereof. However, these methods are
limited only to production of lenses or substrates themselves.
Nevertheless, owing to the remarkable high refractive index of the
transparent resins, there is a strong demand for applying the
transparent resins to coating materials for various substrates or
films.
[0004] However, since coating materials made of the transparent
resins generally exhibit a poor wetting property to various
substrates, it is difficult to stably form a thin film having a
thickness of from several .mu.m to several tens .mu.m.
[0005] As an example of film-like cured products made of thiirane
ring-containing compounds, there are disclosed rapid-curing
adhesives for electronic materials (refer to JP 11-209686A, PCT
Pamphlet WO 00/46317 and JP 2002-173533A). However, these
conventional adhesives all require further addition of curing
agents such as epoxy-based and amine-based curing agents to enhance
a peel strength of the resultant cured products. Further, the above
related documents have failed to specify a refractive index, a
discoloration, a transparency and a uniformity of the adhesives,
since the object thereof is not to study and improve these
properties.
[0006] In addition, there have been proposed compositions composed
of the thiirane ring-containing compound and a silane coupling
agent, for example, spectacle lens compositions (refer to JP
10-298287A) and dental opaque coatings (refer to JP 2003-89759).
However, JP 10-298287A describes no effect obtained by addition of
the silane coupling agent, though it is deemed that the silane
coupling agent is added to control close contact between the lens
and a glass mold. Also, in JP 10-298287A, a massive cured lens is
finally released from the glass mold to achieve the object aimed by
the invention. Thus, the invention described in JP 10-298287A is
quite different in technical concept from the present invention
which is intended to improve the adhesion property, and aims to
produce film-like optical products bonded to a substrate.
[0007] Also, JP 2003-89759A describes thiirane ring-containing
compounds merely as an example of polymerizable monomers, and fails
to provide specific embodiments or examples using the thiirane
ring-containing compounds. Further, in JP 2003-89759A,
(meth)acrylic compounds are specified as the polymerizable
monomers, and in order to satisfy the coating performance, it is
required to use may other components such as fluorocarbon
group-containing polymerizable monomers. In addition, the coating
film described in JP 2003-89759A is used for dental purposes and,
therefore, is required to exhibit a high hiding property. Thus, the
invention described in JP 2003-89759A is also quite different in
technical concept from the present invention seeking a high
transparency.
[0008] An object of the present invention is to provide coating
compositions capable of forming a coating film having a high
refractive index, a less discoloration, and excellent transparency,
uniformity and adhesion property when polymerized and cured;
coating films produced from the composition; and optical products
provided on a surface thereof with the coating film.
DISCLOSURE OF THE INVENTION
[0009] As a result of extensive studies to solve the above
problems, the inventors have found that coating compositions
comprising (A) 100 parts by weight of a thiirane ring-containing
compound, (B) 0.0001 to 10 parts by weight of a catalyst for
accelerating polymerization of the thiirane ring-containing
compound, and (C) 0.005 to 4 parts by weight of a modified silicone
oil can exhibit a good wetting property, and a coating film
obtained by polymerizing and curing the coating composition can
exhibit a high refractive index, a less discoloration and excellent
transparency and uniformity. The present invention has been
accomplished on the basis of the finding
[0010] Further, the inventors have found that when the thiirane
ring-containing compound has at least one structure represented by
the following structural formula (1): ##STR1## the composition
using the compound is suitable as a coating material, and the
coating film produced from the coating composition can exhibit a
higher refractive index.
PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0011] The coating composition of the present invention exhibits a
good wetting property, and is capable of forming on a surface of
glass, plastic, etc., a coating film having a high refractive
index, a less discoloration and excellent transparency, uniformity
and adhesion property. The too thin coating film tends to be
insufficient in protection of a base material or exhibition of its
aimed property, whereas the too thick coating film tends to cause
increase in size and weight of the resultant optical products.
Therefore, the thickness of the coating film is practically about
0.1 to 1000 .mu.m, preferably about 0.5 to 500 .mu.m and more
preferably about 1 to 100 .mu.m.
[0012] The thiirane ring-containing compound (A) used in the
present invention is subjected to ring opening polymerization to
produce a coating film. The thiirane ring-containing compound is
such an organic compound containing one or more thiirane rings in a
molecule thereof. In view of a high refractive index of the
obtained optical elements, the thiirane ring-containing compound is
preferably a compound having at least one structure represented by
the following structural formula (1): ##STR2##
[0013] Further, in view of a good surface hardness of the obtained
coating film, the thiirane ring-containing compound is more
preferably a compound having two or more structures represented by
the structural formula (1), and in view of obtaining a liquid
coating composition having an adequate viscosity for an
easy-handling property thereof, the thiirane ring-containing
compound is still more preferably a chain-like compound having two
or more structures represented by the structural formula (1). When
the above requirements are totally taken into consideration, the
thiirane ring-containing compound is most preferably a compound
represented by the following structural formula (2): ##STR3##
wherein m is an integer of 0 to 4; and n is an integer of 0 to
2.
[0014] Specific examples of the thiirane ring-containing compound
(A) used in the present invention include ethylene sulfide,
propylene sulfide, cyclohexene sulfide, styrene sulfide,
thioglycidol, 1,1-bis(epithioethyl)methane,
tetrakis(.beta.-epithiopropyl)methane,
1,1,1-tris(.beta.-epithiopropyl)propane, (1,3- or
1,4-)-bis(epithioethyl)cyclohexane,
2,5-bis(epithioethyl)-1,4-dithiane, 4-epithioethyl-1,2-cyclohexene
sulfide, 4-epoxy-1,2-cyclohexene sulfide, methylthioglycidyl ether,
bis(.beta.-epithiopropyl)ether,
1,2-bis(.beta.-epithiopropyloxy)ethane,
tetrakis(.beta.-epithiopropyloxymethyl)methane,
1,1,1-tris(.beta.-epithiopropyloxymethyl)propane, bis
[4-(.beta.-epithiopropyloxy)cyclohexyl]methane,
2,2-bis[4-(.beta.-epithiopropyloxy)cyclohexyl]propane, bis
[4-(.beta.-epithiopropyloxy)cyclohexyl]sulfide,
2,5-bis(-epithiopropyloxymethyl)-1,4-dithiane, (1,3- or
1,4-)-bis(.beta.-epithiopropyloxy)benzene, (1,3- or
1,4-)-bis(.beta.-epithiopropyloxymethyl)benzene,
bis[4-(.beta.-epithiopropyloxy)phenyl]methane,
2,2-bis[4-(.beta.-epithiopropyloxy)phenyl]propane,
bis[4-(.beta.-epithiopropyloxy)phenyl]sulfide,
bis[4-(.beta.-epithiopropyloxy)phenyl]sulfone,
4,4'-bis(.beta.-epithiopropyloxy)biphenyl,
bis(.beta.-epithiopropyl)sulfide,
bis(.beta.-epithiopropyl)disulfide,
bis(.beta.-epithiopropyl)trisulfide,
bis(.beta.-epithiopropylthio)methane,
1,2-bis(.beta.-epithiopropylthio)ethane,
1,3-bis(.beta.-epithiopropylthio)propane,
1,2-bis(.beta.-epithiopropylthio)propane,
1,4-bis(.beta.-epithiopropylthio)butane,
1,5-bis(.beta.-epithiopropylthio)pentane,
1,6-bis(.beta.-epithiopropylthio)hexane,
bis(.beta.-epithiopropylthioethyl)sulfide,
tetrakis(.beta.-epithiopropylthiomethyl)methane,
1,1,1-tris(.beta.-epithiopropylthiomethyl)propane,
1,5-bis(.beta.-epithiopropylthio)-2-(.beta.-epithiopropylthiomethyl)-3-th-
iapentane,
1,5-bis(.beta.-epithiopropylthio)-2,4-bis(.beta.-epithiopropylt-
hiomethyl)-3-thiapentane,
1,8-bis(.beta.-epithiopropylthio)-4-(.beta.-epithiopropylthiomethyl)-3,6--
dithiaoctane,
1,8-bis(.beta.-epithiopropylthio)-4,5-bis(.beta.-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,8-bis(.beta.-epithiopropylthio)-4,4-bis(.beta.-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,8-bis(.beta.-epithiopropylthio)-2,4,5-tris(.beta.-epithiopropylthiometh-
yl)-3,6-dithiaoctane,
1,8-bis(.beta.-epithiopropylthio)-2,5-bis(.beta.-epithiopropylthiomethyl)-
-3,6-dithiaoctane,
1,9-bis(.beta.-epithiopropylthio)-5-(.beta.-epithiopropylthiomethyl)-5-[(-
2-.beta.-epithiopropyl othioethyl)thiomethyl]-3,7-dithianonane,
1,10-bis(.beta.-epithiopropylthio)-5,6-bis[(2-.beta.-epithiopropylthioeth-
yl)thio]-3,6,9-trithiadecane,
1,11-bis(.beta.-epithiopropylthio)-4,8-bis(.beta.-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane,
1,11-bis(.beta.-epithiopropylthio)-5,7-bis(.beta.-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane,
1,11-bis(.beta.-epithiopropylthio)-5,7-[(2-.beta.-epithiopropylthioethyl)-
thiomethyl]-3,6,9-trithiaundecane,
1,11-bis(.beta.-epithiopropylthio)-4,7-bis(.beta.-epithiopropylthiomethyl-
)-3,6,9-trithiaundecane,
2,5-bis(epithiopropylthiomethyl)-1,4-dithiane,
2,4,6-tris(epithiopropylthiomethyl)-1,3,5-trithiane, (1,3- or
1,4-)-bis(.beta.-epithiopropylthio)benzene, (1,3- or
1,4-)-bis(.beta.-epithiopropylthiomethyl)benzene,
bis[4-(.beta.-epithiopropylthio)phenyl]methane,
2,2-bis[4-(.beta.-epithiopropylthio)phenyl]propane,
bis[4-(.beta.-epithiopropylthio)phenyl]sulfide,
bis[4-(.beta.-epithiopropylthio)phenyl]sulfone,
4,4'-bis(.beta.-epithiopropylthio)biphenyl,
bis(.beta.-epithiopropyl)selenide,
bis(.beta.-epithiopropyl)diselenide,
bis(.beta.-epithiopropyl)telluride,
bis(.beta.-epithiopropyl)ditelluride, vinylphenylthioglycidyl
ether, vinylbenzylthioglycidyl ether, thioglycidyl methacrylate,
thioglycidyl acrylate and allylthioglycidyl ether, as well as
thiirane ring-containing compounds obtained by replacing one or
more hydrogen atoms of the above exemplified compounds with methyl
groups.
[0015] Among these thiirane ring-containing compounds (A), more
preferred are bis(.beta.-epithiopropyl)sulfide,
bis(.beta.-epithiopropyl)disulfide,
bis(.beta.-epithiopropyl)trisulfide,
bis(.beta.-epithiopropylthio)methane,
1,2-bis(.beta.-epithiopropylthio)ethane,
1,3-bis(.beta.-epithiopropylthio)propane,
1,4-bis(.beta.-epithiopropylthio)butane,
1,5-bis(.beta.-epithiopropylthio)pentane,
1,6-bis(.beta.-epithiopropylthio)hexane and
bis(.beta.-epithiopropylthioethyl)sulfide.
[0016] Specific examples of the catalyst for accelerating
polymerization of the thiirane ring-containing compound include
amines such as triethylamine, N,N-dimethyl cyclohexylamine,
N,N-diethylethanol amine, N,N-dimethyl aniline, pyridine, N-methyl
piperidine, piperazine triethylene diamine and imidazole,
phosphines such as tri-n-butyl phosphine and triphenyl phosphine,
quaternary ammonium salts such as tetra-n-butyl phosphonium
bromide, tetra-n-butyl ammonium bromide, triethylene benzyl
ammonium chloride, cetyldimethyl benzyl ammonium chloride and
1-n-dodecyl pyridinium chloride, quaternary phosphonium salts such
as tetraphenyl phosphonium bromide.
[0017] Although only a part of the catalysts (B) for accelerating
polymerization of the thiirane ring-containing compound are
illustrated above, the catalyst (B) is not particularly limited to
these illustrative compounds, and any suitable compounds may be
used as the catalyst (B) as long as they can exhibits the effect of
accelerating the polymerization. Also, these catalysts may be used
alone or in the form of a mixture of any two or more thereof. The
amount of the catalyst (B) added is 0.0001 to 10.0 parts by weight
and preferably 0.0005 to 5.0 parts by weight based on 100 parts by
weight of the thiirane ring-containing compound (A).
[0018] Also, in addition to the catalyst for accelerating the
polymerization, a polymerization controller may be added to the
composition, if required, in order to control the polymerization
reaction. Examples of the polymerization controller effectively
used in the coating composition of the present invention include
halides of elements belonging to Groups 13 to 16 of the long-form
Periodic Table such as typically halogenated tin compounds and
halogenated germanium compounds. These polymerization controllers
may be used alone or in the form of a mixture of any two or more
thereof. The amount of the polymerization controller used is 0.0001
to 10.0 parts by weight based on 100 parts by weight of the
thiirane ring-containing compound (A).
[0019] The modified silicone oil (C) used in the present invention
is represented by any of the following structural formulae (3) to
(6), and the addition of the modified silicone oil (C) allows the
coating composition to be improved in wetting property. ##STR4##
wherein X is each independently halogen, an alkoxy group having 1
to 36 carbon atoms, an alkyl group having 1 to 36 carbon atoms, an
aliphatic ester group having 1 to 36 carbon atoms, a polyether
group which may contain a hydrocarbon group having 1 to 36 carbon
atoms in total, etc.; and y and z are each independently an integer
of 1 or more.
[0020] In view of the positional structure, the modified silicone
oils (C) are generally classified into a side chain-modified type
represented by the above structural formula (3), a side chain/both
terminal end-modified type represented by the above structural
formula (4), one terminal end-modified type represented by the
above structural formula (5) and a both terminal end-modified type
represented by the above structural formula (6). Also, in view of
the chemical structure, the modified silicone oils (C) are
generally classified into reactive types such as an amino-modified
type, an epoxy-modified type, a carboxyl-modified type, a
carbinol-modified type, a (meth)acryloyl-modified type, a
mercapto-modified type, a phenol-modified type and a different
functional group-modified type, and non-reactive types such as a
polyether-modified type, a methylstyryl-modified type, an
alkyl-modified type, a higher fatty ester-modified type, a
hydrophilic special modified type, a higher alkoxy-modified type, a
fluorine-modified type and a higher fatty acid-containing type.
[0021] In the present invention, among the above positional
structure-classified modified silicone oils, preferred are the side
chain-modified type silicone oils represented by the structural
formula (3) and the both terminal end-modified type silicone oils
represented by the structural formula (6), whereas among the above
chemical structure-classified modified silicone oils, preferred are
the silicone oils of a mercapto-modified type, a polyether-modified
type and an epoxy-modified type, and more preferred are the
silicone oils of a polyether-modified type having a surface active
performance.
[0022] Specific examples of the preferred modified silicone oils
include commercial products available from Shin-Etsu Chemical Co.,
Ltd., under tradenames "KF-101", "KF-102", "KF-105", "KF-351",
"KF-352", "KF-618", "KF-945", "KF-2001", "KF-2004", "X-22-163A",
"X-22-163B", "X-22-167B", "X-22-169AS", "X-22-2000" and
"X-22-4741", and commercial products available from BYK Chemie
Japan Co., Ltd., under tradenames "BYK-307", "BYK-325" and
"BYK-333".
[0023] These modified silicone oils (C) may be used alone or in the
form of a mixture of any two or more thereof. The amount of the
modified silicone oil (C) added is 0.005 to 4.0 parts by weight,
preferably 0.005 to 3.0 parts by weight and more preferably 0.1 to
2.0 parts by weight based on 100 parts by weight of the thiirane
ring-containing compound. When the amount of the modified silicone
oil (C) added is less than 0.005 part by weight, the obtained
coating composition tends to be insufficient in wetting property.
When the amount of the modified silicone oil (C) added is more than
4 parts by weight, the coating film obtained from the coating
composition tends to be deteriorated in transparency.
[0024] In the present invention, the coating composition may
further contain (D) a silane coupling agent represented by the
following structural formula (7), if required, to form a coating
film having excellent uniformity and adhesion property: ##STR5##
wherein R.sup.1, R.sup.2 and R.sup.3 are each independently
halogen, an alkoxy group having 1 to 4 carbon atoms or an alkyl
group having 1 to 4 carbon atoms; R.sup.4 is a single bond or an
alkylene group having 1 to 4 carbon atoms which may contain an
alkyl side chain having 1 to 4 carbon atoms; and R.sup.5 is a
reactive group such as a vinyl group; a styryl group; a
(meth)acryloyl group; an epoxy-containing group, e.g., glycidyl
group; an amino-containing group, e.g., amino group,
aminoethylamino group and phenylamino group; a mercapto group; an
isocyanate group; a halogen group; and an ureido group, which may
contain an alkyl side chain having 1 to 4 carbon atoms.
[0025] Specific examples of the silane coupling agent (D) include
vinyl trichlorosilane, vinyl trimethoxysilane, vinyl
triethoxysilane, 4-styryl trimethoxysilane, .gamma.-acryloxypropyl
trimethoxysilane, .gamma.-methacryloxypropyl trimethoxysilane,
.gamma.-methacryloxypropyl triethoxysilane,
.gamma.-methacryloxypropylmethyl dimethoxysilane,
.gamma.-methacryloxypropylmethyl diethoxysilane,
.gamma.-glycidoxypropyl trimethoxysilane, .gamma.-glycidoxypropyl
triethoxysilane, .gamma.-glycidoxypropylmethyl dimethoxysilane,
.gamma.-glycidoxypropylmethyl diethoxysilane,
.beta.-(3,4-epoxycyclohexyl)ethyl trimethoxysilane,
.gamma.-(3,4-epoxycyclohexyl)propyl trimethoxysilane,
.gamma.-aminopropyl trimethoxysilane, .gamma.-aminopropyl
triethoxysilane, N-aminoethyl-.gamma.-aminopropyl trimethoxysilane,
N-aminoethyl-.gamma.-aminopropyl triethoxysilane,
N-aminoethyl-.gamma.-aminopropylmethyl dimethoxysilane,
N-aminoethyl-.gamma.-aminopropylmethyl diethoxysilane,
N-phenyl-.gamma.-aminopropyl trimethoxysilane,
.gamma.-mercaptopropyl trimethoxysilane, .gamma.-mercaptopropyl
triethoxysilane, .gamma.-mercaptopropylmethyl dimethoxysilane,
.gamma.-mercaptopropylmethyl diethoxysilane,
.gamma.-isocyanatopropyl trimethoxysilane, .gamma.-isocyanatopropyl
triethoxysilane, .gamma.-chloropropyl trimethoxysilane,
.gamma.-chloropropyl triethoxysilane, .gamma.-ureidopropyl
trimethoxysilane, .gamma.-ureidopropyl triethoxysilane and
bis(triethoxysilylpropyl)tetrasulfide.
[0026] Among the preferred silane coupling agents (D) illustrated
above, more preferred are the epoxy- or mercapto-containing silane
coupling agents such as .gamma.-glycidoxypropyl trimethoxysilane,
.gamma.-glycidoxypropyl triethoxysilane,
.gamma.-glycidoxypropylmethyl dimethoxysilane,
.gamma.-glycidoxypropylmethyl diethoxysilane,
.beta.-(3,4-epoxycyclohexyl)ethyl trimethoxysilane,
.gamma.-(3,4-epoxycyclohexyl)propyl trimethoxysilane,
.gamma.-mercaptopropyl trimethoxysilane, .gamma.-mercaptopropyl
triethoxysilane, .gamma.-mercaptopropylmethyl dimethoxysilane and
.gamma.-mercaptopropylmethyl diethoxysilane, and still more
preferred are the mercapto-containing silane coupling agents such
as .gamma.-mercaptopropyl trimethoxysilane, .gamma.-mercaptopropyl
triethoxysilane, .gamma.-mercaptopropylmethyl dimethoxysilane and
.gamma.-mercaptopropylmethyl diethoxysilane.
[0027] These silane coupling agents (D) may be used alone or in the
form of a mixture of any two or more thereof. The amount of the
silane coupling agent (D) added is preferably 1 to 30 parts by
weight and more preferably 1 to 20 parts by weight based on 100
parts by weight of the thiirane ring-containing compound (A).
[0028] In the present invention, the coating composition may
further contain, if required, an inorganic filler to obtain a
coating film having excellent refractive index and hardness.
[0029] Specific examples of the inorganic filler include silica,
alumina, calcium oxide, titania, cerium oxide, zirconia, zinc
oxide, tin oxide, cadmium oxide, antimony oxide, composite
materials of these compounds, and fillers obtained by introducing a
polymerizable functional group into these compounds. To ensure a
good transparency of the resultant product, these inorganic fillers
preferably have a fine particle size, more specifically, have a
number-average particle size of 50 nm or less.
[0030] The inorganic fillers illustrated above may be used alone or
in the form of a mixture of any two or more thereof. The amount of
the inorganic filler added is 1 to 100 parts by weight and
preferably 5 to 50 parts by weight based on 100 parts by weight of
the thiirane ring-containing compound (A).
[0031] Also, in the case where the inorganic filler is added to the
coating composition, in order to enhance the dispersibility, etc.,
there may be used known solvents or dispersants which are suitably
used in ordinary applications.
[0032] In the present invention, the coating composition may
further contain, if required, a thiol group-containing compound
other than the silane coupling agents to form a coating film
exhibiting a less discoloration and an excellent transparency. The
thiol group-containing compound means an organic compound
containing one or more thiol groups in a molecule thereof. In view
of enhancing the hardness of the resultant coating film, the use of
such a compound having two or more thiol groups is preferred.
[0033] Specific examples of the thiol group-containing compound
include methane dithiol, methane trithiol, 1,2-dimercaptoethane,
bis(2-mercaptoethyl)sulfide, bis(2,3-dimercaptopropyl)sulfide,
1,2,3-trimercaptopropane, 2-mercaptomethyl-1,3-dimercaptopropane,
4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane,
2,4-bis(mercaptomethyl)-1,5-dimercapto-3-thiapentane,
4,8-bis(mercaptomethyl)-1,11-dimercapto-3,6,9-trithiaundecane,
4,7-bis(mercaptomethyl)-1,11-dimercapto-3,6,9-trithiaundecane,
5,7-bis(mercaptomethyl)-1,11-dimercapto-3,6,9-trithiaundecane,
1,2,7-trimercapto-4,6-dithiaheptane,
1,2,9-trimercapto-4,6,8-trithianonane,
1,2,8,9-tetramercapto-4,6-dithianonane,
1,2,10,11-tetramercapto-4,6,8-trithiaundecane,
1,2,12,13-tetramercapto-4,6,8,10-tetrathiatridecane,
tetrakis(mercaptomethyl)methane,
tetrakis(4-mercapto-2-thiabutyl)methane,
tetrakis(7-mercapto-2,5-dithiaheptyl)methane, trimethylolpropane
tris(2-mercaptoacetate), trimethylolpropane
tris(3-mercaptopropionate), pentaerythritol
tetrakis(2-mercaptoacetate), pentaerythritol
tetrakis(3-mercaptopropionate),
2,5-bis(mercaptomethyl)-1,4-dithiane, bis(4-mercaptophenyl)sulfide,
bis(4-mercaptomethylphenyl)methane,
2,2-bis(4-mercaptomethylphenyl)propane,
bis(4-mercaptomethylphenyl)ether and
bis(4-mercaptomethylphenyl)sulfide.
[0034] The preferred thiol group-containing compounds illustrated
above may be used alone or in the form of a mixture of any two or
more thereof. The amount of the thiol group-containing compound
added is 0.1 to 100 parts by weight and preferably 1 to 50 parts by
weight based on 100 parts by weight of the thiirane ring-containing
compound (A).
[0035] Further, in order to desirably control properties of the
coating film obtained by curing the coating composition, a compound
which is reactive with a part or whole of the composition may be
further added thereto, if required. Examples of the compound
reactive with a part or whole of the composition include epoxy
compounds, iso(thio)cyanates, carboxylic acids, carboxylic
anhydrides, phenols, amines, vinyl compounds, allyl compounds,
acrylic compounds and methacrylic compounds. The compound which is
reactive with a part or whole of the composition may be added to
the composition in an amount of 1 to 200 parts by weight based on
100 parts by weight of the thiirane ring-containing compound
(A).
[0036] In the polymerization and curing method used in the present
invention, the coating composition applied onto an optical element
is heated at a temperature of 20 to 200.degree. C. for a period of
from several minutes to several days to obtain an optical product
having a cured coating film. Examples of a heating source used for
curing the coating composition include an electric oven, a constant
temperature oven and a dryer.
[0037] The coating composition of the present invention may also
contain various additives, e.g., antioxidants such as phenol-based
compounds and phosphite-based compounds, bluing agents such as
oil-soluble dyes, typically anthraquinone-based compounds,
ultraviolet absorbers such as benzophenone-based compounds and
benzotriazole-based compounds, thixotropic agents and antistatic
agents to enhance utility of the resultant optical elements.
[0038] Upon applying the coating composition, a diluent, etc., may
be added thereto, if required, to suitably control a viscosity of
the composition. Examples of the diluent include generally used
organic solvents such as ethanol, acetone, MEK, ethyl acetate, THF,
toluene and methylene chloride. The coating composition may be
applied using a coating device such as a hand coater, a bar coater
and a spin coater, if required.
[0039] The coating composition of the present invention may be
applied onto various substrates according to uses and applications
thereof, thereby generally exhibiting a good wetting property
thereon. Examples of the substrate include substrates made of
plastic materials such as PMMA, PET, PC, cellulose triacetate (TAC)
and alicyclic polyolefins, substrates made of inorganic material
such as glass, quartz and ceramic materials, and substrates made of
metals such as aluminum, stainless steel (SUS) and nickel.
Meanwhile, a surface of the plastic substrate having a poor
chemical resistance is preferably protected with an inorganic thin
film made of silica, etc.
[0040] The coating composition is preferably handled and dealt with
in a clean room to avoid inclusion of dusts or foreign matters
thereinto, and may be cured in a flowing inert gas atmosphere such
as nitrogen and helium or by covering the coating film with an
appropriate film.
[0041] The coating composition is preferably previously subjected
to deaeration treatment and filtration treatment before
polymerization and curing thereof to obtain an optical element
having a high transparency. The deaeration treatment is usually
conducted under a reduced pressure of 0.001 to 50 torr at a
temperature of 0 to 100.degree. C. for 1 min to 24 h, and the
filtration treatment may be conducted by passing through a filter
made of PTFE or PET having a pore diameter of about 0.05 to 10
.mu.m.
EXAMPLES
[0042] The present invention will be described in more detail by
reference to the following examples, but it should be noted that
these examples are only illustrative and not intended to limit the
scope of the present invention thereto.
Example 1
[0043] One hundred parts by weight of
bis(.beta.-epithiopropyl)sulfide, 1.0 part by weight of tetrabutyl
phosphonium bromide and 0.1 part by weight of a modified silicone
oil "KF-351 (tradename)" available from Shin-Etsu Chemical Co.,
Ltd., were intimately mixed with each other to obtain a uniform
coating composition. The thus obtained coating composition was
deaerated at 20.degree. C. under 1 torr for 5 min, and filtered
through a 0.5 .mu.m-mesh PTFE membrane filter. Next, the thus
treated coating composition was applied onto a PET (polyethylene
terephthalate) substrate using a bar coater (#09) to prepare a
sample. The thus obtained sample was heated and cured at
120.degree. C. for 5 min. Evaluation results of a wetting property
of the coating composition as well as a discoloration, transparency
and uniformity of the resultant cured product are shown in Table
1.
[0044] Meanwhile, the wetting property, discoloration, transparency
and uniformity were evaluated by the following methods, and Rank B
or more was regarded as being acceptable.
[0045] The wetting property was evaluated according to the
following ratings by observing a retention time of the coating film
after coating by naked eyes.
[0046] A: No cissing occurred for 1 h or longer;
[0047] B: Cissing occurred within 1 h; and
[0048] C: Cissing occurred within 10 min.
[0049] The discoloration was evaluated according to the following
ratings by observing a coated substrate placed on a white paper by
naked eyes.
[0050] A: No discoloration observed;
[0051] B: Yellowish discoloration slightly observed; and
[0052] C: Yellowish discoloration clearly observed.
[0053] The transparency was evaluated according to the following
ratings by observing a coated substrate placed on a black paper by
naked eyes under a fluorescent lamp in a dark room.
[0054] A: Transparent;
[0055] B: Slight blooming observed; and
[0056] C: Completely opaque.
[0057] The uniformity was evaluated according to the following
ratings by observing a surface condition of a coating film by naked
eyes.
[0058] A: Flat coating surface;
[0059] B: Substantially flat coating surface; and
[0060] C: Noticed irregularities on a coating surface.
Examples 2 to 4 and Comparative Examples 1 to 3
[0061] The same procedure as in Example 1 was repeated except that
the amount of the modified silicone oil added ("KF-351 (tradename)"
available from Shin-Etsu Chemical Co., Ltd.) was changed as shown
in Table 1. The results are shown in Table 1.
Example 5 to 17
[0062] The same procedure as in Example 1 was repeated except that
the modified silicone oil was replaced with those shown in Table 2.
The results are shown in Table 1. Meanwhile, the modified silicone
oils represented by model names having capitals of "KF" and "X-22"
are products available from Shin-Etsu Chemical Co., Ltd., and the
modified silicone oils represented by model names having capitals
of "BYK" are products available from BYK Chemie Japan Co., Ltd.
TABLE-US-00001 TABLE 1 Amount of Kind of modified modified silicone
silicone oil oil added (wt part) Kind of substrate Example 1 KF-351
0.1 PET Example 2 KF-351 0.01 PET Example 3 KF-351 1.0 PET Example
4 KF-351 3.0 PET Comparative None 0 PET Example 1 Comparative
KF-351 0.001 PET Example 2 Comparative KF-351 5.0 PET Example 3
Wetting Evaluation of property discoloration Transparency
Uniformity Example 1 A A A A Example 2 B A A A Example 3 A A B A
Example 4 A A B A Comparative C A A C Example 1 Comparative C A A B
Example 2 Comparative A A C A Example 3
[0063] TABLE-US-00002 TABLE 2 Kind of modified silicone oil Kind of
(wt part) substrate Wetting property Example 5 KF-351 (0.1) PET A
Example 6 KF-945 (0.1) PET A Example 7 KF-618 (0.1) PET A Example 8
BYK-307 (0.1) PET A Example 9 BYK-325 (0.1) PET A Example 10
BYK-333 (0.1) PET A Example 11 X-22-167B (0.1) PET A Example 12
KF-2001 (0.1) PET B Example 13 KF-105 (0.1) PET A Example 14
X-22-163A (0.1) PET A Example 15 KF-101 (0.1) PET A Example 16
X-22-169AS (0.1) PET A Example 17 X-22-4741 (0.1) PET A Evaluation
of discoloration Transparency Uniformity Example 5 A A A Example 6
A A A Example 7 A A B Example 8 A A A Example 9 A A A Example 10 A
A A Example 11 A A B Example 12 A A B Example 13 A A A Example 14 A
A A Example 15 A A A Example 16 A A A Example 17 A A A
Examples 18 and 19
[0064] The same procedure as in Example 1 was repeated except that
the kinds and amounts of modified silicone oils as well as the
kinds of substrates were changed as shown in Table 3. Meanwhile,
"TAC" represents a cellulose triacetate resin, and "Zeonor"
represents a tradename of an alicyclic polyolefin resin available
from Nippon Zeon Co., Ltd.
Examples 20 to 22
[0065] The same procedure as in Example 1 was repeated except that
"BYK-325 (tradename)" available from BYK Chemie Japan Co., Ltd.,
was used as the modified silicone oil in an amount of 1.0 part by
weight, and the kinds of substrates were changed as shown in Table
3. Meanwhile, "SUS304" was used as the stainless steel.
Example 23
[0066] One hundred parts by weight of
bis(.beta.-epithiopropyl)sulfide, 1.0 part by weight of tetrabutyl
phosphonium bromide, 1.0 part by weight of a modified silicone oil
"BYK-325 (tradename)" available from BYK Chemie Japan Co., Ltd.,
and 10 parts by weight of .gamma.-mercaptopropyl trimethoxysilane
"KBM-803 (tradename)" available from Shin-Etsu Chemical Co., Ltd.,
were intimately mixed with each other to obtain a uniform coating
composition. The thus obtained coating composition was deaerated at
20.degree. C. under 1 torr for 5 min, and filtered through a 0.5
.mu.m-mesh PTFE membrane filter. Next, the thus treated coating
composition was applied onto a glass substrate using a bar coater
(#09) to prepare a sample. The thus obtained sample was heated at
120.degree. C. for 5 min, and further heated and cured at
70.degree. C. for 20 h. Evaluation results of a wetting property of
the coating composition as well as a discoloration, transparency,
uniformity and adhesion property of the resultant cured product are
shown in Table 4.
[0067] Meanwhile, the adhesion property was evaluated according to
the following ratings by immersing a coated substrate in 80.degree.
C. hot water for 1 h, and then observing the coated substrate by
naked eyes.
[0068] .largecircle.: No separation of coating film from substrate
occurred; and
[0069] .times.: Separation of coating film from substrate
occurred
Examples 24 and Comparative Example 4
[0070] The same procedure as in Example 23 was repeated except that
the silane coupling agent was changed as shown in Table 4.
Meanwhile, "KBM-403 (.gamma.-glycidoxypropyl trimethoxysilane)" is
a silane coupling agent available from Shin-Etsu Chemical Co., Ltd.
TABLE-US-00003 TABLE 3 Kind of modified silicone oil (wt part) Kind
of substrate Wetting property Example 18 KF-351 (0.1) TAC A Example
19 BYK-325 (0.5) Zeonor A Example 20 BYK-325 (1.0) Glass A Example
21 BYK-325 (1.0) Quartz A Example 22 BYK-325 (1.0) Stainless steel
A Evaluation of discoloration Transparency Uniformity Example 18 A
A A Example 19 A A A Example 20 A B B Example 21 A B B Example 22 A
B A
[0071] TABLE-US-00004 TABLE 4 Kind of modified Kind of silane
silicone oil coupling agent Kind of Wetting (wt part) (wt part)
substrate property Example 23 BYK-325 (1.0) KBM-803 (10) Glass A
Example 24 BYK-325 (1.0) KBM-403 (10) Glass A Comparative BYK-325
(1.0) None Glass A Example 4 Evaluation of Adhesion discoloration
Transparency Uniformity property Example 23 A B B .largecircle.
Example 24 A B B .largecircle. Comparative A B B X Example 4
INDUSTRIAL APPLICABILITY
[0072] In accordance with the present invention, there is provided
a coating composition comprising (A) 100 parts by weight of a
thiirane ring-containing compound, (B) 0.0001 to 10 parts by weight
of a catalyst for accelerating polymerization of the thiirane
ring-containing compound, and (C) 0.005 to 4 parts by weight of a
modified silicone oil. The coating composition of the present
invention exhibits a good wetting property, and is capable of
forming a coating film having a high refractive index, a less
discoloration and excellent transparency and uniformity.
* * * * *