Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Reexamination Certificate
2002-01-25
2004-03-16
Davis, Brian (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C556S410000, C556S446000, C556S448000, C524S858000
Reexamination Certificate
active
06706906
ABSTRACT:
The present invention relates to a water repellent composition capable of forming a surface treatment layer on which water droplets are less likely to deposit or from which deposited water droplets can easily be removed, a surface-treated substrate having a surface treatment layer formed of such a water repellent composition, a process for producing such a substrate, and an article for transportation equipment, which comprises such a substrate.
It is desirable to impart to a substrate surface a property whereby water droplets are less likely to become deposited upon said substrate surface and wherein deposited water droplets can easily be removed (such a property will hereinafter be referred to as a water droplet removal property). In order to impart the water droplet removal property to a substrate surface, a hydrophilic oil repellent treating agent comprising a fluorine-containing silane compound and a hydrophilic silane compound, has, for example, been proposed (JP-A-5-331455). However, this surface treating agent is hydrophilic, and thus can not be applied to an article for a transport equipment which is desired to have water repellency.
It is an object of the present invention to provide a water repellent composition capable of forming a surface treatment layer which has an excellent water droplet removal property and is also excellent in its durability (abrasion resistance, chemical resistance, weather resistance, etc.). Further, another object is to provide a surface-treated substrate having a surface treatment layer formed of such a water repellent composition, a process for producing such a substrate, and an article for a transportation equipment.
The present invention provides a water repellent composition (hereinafter referred to as the water repellent composition (I)) comprising a compound of the following formula 1 (hereinafter referred to as the compound 1, and other compounds will also be likely referred to), and a compound of the following formula 4 and/or a compound of the following formula 5:
R
f
Si(R)
p
(X)
3−p
Formula 1
R
F
Si(R
1
)
q
(X
1
)
3−q
Formula 4
SiX
2
4
Formula 5
wherein R
f
is a fluorine-containing organic group having an etheric oxygen atom, R
F
is a fluorine-containing organic group having no etheric oxygen atom, each of R and R
1
which are independent of each other, is a C
1-6
hydrocarbon group containing no fluorine atom, each of X, X
1
and X
2
which are independent of one another, is a halogen atom or a hydrolyzable group, and each of p and q which are independent of each other, is 0, 1 or 2.
Compound 1 is a compound having a fluonne-containing organic group having an etheric oxygen atom (the fluorine-containing organic group having an etheric oxygen atom will hereinafter be referred to as a R
f
group) at one molecular terminal, and having a reactive group at the other molecular terminal. The R
f
group contributes to improvement of the mobility or a sliding nature of water droplets on the surface treatment layer formed of the water repellent composition (I). The detailed mechanism of such improvement is not known, but it is considered that since the R
f
group contains fluorine atoms, the surface energy of the surface treatment layer formed of the water repellent composition (I) can be made small, and due to its high molecular chain mobility attributable to the structure connected by the etheric oxygen atom, the surface treatment layer is able to efficiently align fluorine atoms. Namely, the high molecular chain mobility makes change in alignment of fluorine atoms in correspondence with the movement of water droplets on the surface of the surface treatment layer possible, whereby the sliding nature of water droplets will be increased.
The fluorine-containing organic group having no etheric oxygen atom in the surface treating agent heretofore proposed, likewise contains fluorine atoms, whereby the surface energy of the treatment layer formed of such a surface treating agent can be made small. However, the fluorine-containing organic group having no etheric oxygen atom has a very rigid structure, whereby fluorine atoms present on the surface can hardly undergo change in alignment and can not follow the movement of water droplets. Accordingly, it is considered that water droplets may slide efficiently in certain regions but tend to hardly slide in other regions, and thus, water droplets will be anchored somewhere, and the sliding nature of water droplets tends to be low.
In the water repellent composition (I), the compound 1 may be composed of one type or two or more types.
The structure of the R
f
group in the compound 1 is not particularly limited. In the compound 1, R
f
is preferably a group represented by F(CF
2
)
a
O[CF(Y)CF
2
O]
n
—A—, wherein A is a C
2-32
bivalent organic group (provided that a bivalent organic group consisting solely of CF(Y)CF
2
O is excluded), a is an integer of from 2 to 8, Y is a fluorine atom or CF
3
, and n is an integer of from 0 to 50.
Namely, as the compound 1, a compound of the following formula 2 is preferred from the viewpoint of the water droplet removal property or its durability. In the following formula, a, n, A, R, p and X are as defined above.
F(CF
2
)
a
O[CF(CF
3
)CF
2
O]
n
—A—Si(R)
p
(X)
3−p
Formula 2
In the formula 1 or 2, R is preferably a methyl group or an ethyl group, from the viewpoint of the durability. The hydrolyzable group for X is preferably an alkoxy group, an acyloxy group, a ketoxime group, an alkenyloxy group, an amino group, an aminoxy group, an amide group or an isocyanate group. X is preferably at least one member selected from the group consisting of a halogen atom (especially a chlorine atom), an alkoxy group and an isocyanate group. The larger the number of X i.e. (3−p), the better, since the adhesion will be excellent, and p is particularly preferably 0 or 1. n is preferably from 0 to 20, since the denseness of the surface treatment layer can thereby be made high. a is preferably 2, 3 or 4, particularly preferably 3.
A is preferably a group represented by A
1
—R
2
, wherein A
1
is a C
1-16
polyfluoroalkylene group, and R
2
is a C
1-16
bivalent organic group, from the viewpoint of the water droplet removal property or its durability. A
1
may be of a straight chain structure or a branched structure. A
1
is preferably a perfluoroalkylene group, particularly preferably —CF(CF
3
)(CF
2
)
z
—, wherein z is an integer of at least 0, preferably 0, 1, 2, 3 or 4, or —(CF
2
)
y
—, wherein y is an integer of at least 1, preferably 2, 3 or 4.
R
2
is preferably a C
1-16
bivalent hydrocarbon group containing no fluorine atom. However, it may contain an etheric oxygen atom in its molecule. R
2
may be of a straight chain structure or a branched structure, but preferably of a straight chain structure. R
2
is preferably —(CH
2
)
s
—, wherein s is an integer of from 2 to 16, preferably 2, 3 or 4, —(CH
2
)
t
—O—(CH
2
)
u
—, wherein t is an integer of from 2 to 10, preferably 2, 3 or 4, and u is an integer of from 2 to 14, preferably 2, 3 or 4, provided that t+u is from 2 to 16.
Specific examples of the compound 1 will be shown below.
F[CF(CF
3
)CF
2
O]
2
(CF
2
)
2
(CH
2
)
2
SiCl
3
Compound 1A
F[CF(CF
3
)CF
2
O](CF
2
)
2
(CH
2
)
2
O(CH
2
)
3
SiCl
3
Compound 1B
F[CF(CF
3
)CF
2
O]
6
(CF
2
)
2
(CH
2
)
2
SiCl
3
Compound 1C
F[CF(CF
3
)CF
2
O]
6
(CF
2
)
2
(CH
2
)
2
Si(OCH
3
)
3
Compound 1D
F[CF(CF
3
)CF
2
O]
2
(CF
2
)
2
(CH
2
)
2
Si(NCO)
3
Compound 1E
The compound 1 may be used as it is or in the form of a hydrolyzed product. The hydrolyzed product of the compound 1 is meant for a compound obtained by hydrolyzing all or some of reactive groups of the compound 1 in water or in an acidic or alkaline aqueous solution. As the acidic aqueous solution, an aqueous solution of e.g. hydrochloric acid, acetic acid, sulfuric acid, phosphoric acid, sulfonic acid, methansulfonic acid or p-tolu
Furukawa Yutaka
Torimoto Noriko
Yoneda Takashige
Asahi Glass Company Limited
Davis Brian
LandOfFree
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