Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2000-04-19
2004-05-11
Tsoy, Elena (Department: 1762)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S429000, C528S012000, C528S036000, C106S287160, C427S299000, C427S387000, C427S389700
Reexamination Certificate
active
06733892
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a surface treatment composition which imparts excellent water repellency and waterdrop rolling property to the surface of a substrate, a substrate treated with the surface treatment composition and a method for its production.
BACKGROUND ART
Glass, plastic, ceramic and metal substrates and substrates having treated surface layers are used in various fields. A problem with these substrates is the adverse effects of dirt on their surfaces such as water and dust.
For example, for transports such as electric railcars, automobiles, ships and aircrafts, it is desirable to keep the exterior parts such as outer panels, windowpanes, mirrors and surface panels of display signs, the interior parts such as surface panels of measuring instruments and other equipments clean. However, deposition of raindrops, dust and soil or water condensation due to the influence of the atmospheric humidity and temperature on the surfaces of transport equipments not only can cause a problem of damage to their appearances but also causes an uncomfortable impression and sanitary problems in a case of a directly visible or touchable substrate and impair the essential functions of the transport equipments. Especially, in cases of transport equipments required to be transparent or see-through such as windowpanes and mirrors, reduction in transparency and the see-through property is problematic.
On the other hand, removal of dust, soil or water by wiping or with a wiper can cause a problem of fine scratches on the substrate surface. Further, foreign particles accompanying dust, soil or water can aggravate the scratches. Furthermore, water deposited on a glass surface can erode the surface by eluting glass components and causes a phenomenon called “scorching”. However, strong abrasion for removal of scorch marks can problematically lead to formation of fine irregularities. If severely scorched glass or glass having fine irregularities on the surface is used for a see-through part, it can ruin the essential function of the see-through part, causing terrible light scattering on the surface. Therefore, it is difficult to secure visibility.
In addition, dust, soil and water cause problems of promotion of damage, fouling, discoloration and corrosion on the surfaces of transport equipments and problems of induction of change in their electrical properties, mechanical properties and optical properties. These problems also exist in the fields of building materials and decorations and equipments for electric and electronic appliances.
Surface treatment of a substrate with a composition containing a partial hydrolysate of a fluorine-containing reactive silane as an essential component with a view to imparting the property of repelling waterdrops and removing their adverse effects (hereinafter referred to as water repellency), the antifouling property and low reflectivity, can be accomplished by known methods disclosed in the following publications.
JP-A-50-126033, JP-A-59-115840, JP-A-61-40845, JP-A-61-241143, JP-A-61-215235, JP-A-1-95181, JP-A-2-248480, JP-A-2-115801, JP-A-4-341379, JP-A-4-342444, JP-A-4-328188, JP-A-5-279499 and JP-A-1-170486.
These publications disclose partial hydrolysis of a fluorine-containing reactive silane with an acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid and a sulfonic acid.
However, conventional compositions have problems of uneven application, unsatisfactory adhesiveness to a substrate and the unenduring antifouling property. Besides, treatment of a substrate incorporated in an article or in or after use with a water and oil repellent has to be done at ordinary temperature. For example, it is economically disadvantageous to detach the front windshield of an automobile which is already on sale for its treatment. Further, it is out of the question to treat the front windshield without detaching it and then bake the whole automobile. Because it is impossible to prepare a composition afresh each time treatment is done, such a composition is required to be functional over a long time and have good storage stability.
However, conventional compositions have limited applications due to problems of their low storage stability and difference in their post-storage performance. Conventional compositions proposed so far do not have the property of draining waterdrops on the surface of a substrate (hereinafter referred to as the waterdrop rolling property) as well as the above-mentioned properties and have a problem that when they are applied to transport equipments, visibility can not be secured.
DISCLOSURE OF THE INVENTION
The present inventors have studied to overcome the above-mentioned drawbacks of conventional compositions. As a result, they have found out that the above-mentioned drawbacks are attributed to inappropriately selected partial hydrolysis conditions which lead to a high proportion of molecules with low- or high-molecular weights in the resulting partial hydrolysate and a composition having large acid and water contents.
They have also found out that a surface treatment agent containing a specific partial hydrolysate is excellent in water repellency, antifouling property, waterdrop rolling property, adhesiveness (durability), abrasion resistance, chemical resistance and storage stability.
Namely, the present invention provides a surface treatment composition containing a partial hydrolysate of a fluorine-containing reactive silane represented by the following formula 1 as an essential component, which the proportion (T
1
) of molecules with molecular weights of at most 2 M calculated from the following formula A in the partial hydrolysate is less than 70%, and the proportion (T
2
) of molecules with molecular weights of at least 6 M calculated from the following formula B in the partial Th hydrolysate is less than 10%, wherein M is the molecular weight of the fluorine-containing reactive silane measured by gel permeation chromatography:
[Ka2]
(R
f
—Q—) a (R
1
)
b
Si (X
1
)
4
−a−b formula 1
wherein
R
f
: a monovalent fluorine-containing C
1-30
organic group,
Q: a single bond or a bivalent linking group,
R
1
: a hydrogen atom or a monovalent C
1-16
organic group,
a: 1 or 2,
b: 0 or 1, and (a+b) is 1 or 2, and
X
1
: a hydrolyzable group,
[Su3]
T
1
(%)=[
W
2
/W
1
]×100 formula A
T
2
(%)=[
W
3
/W
1
]×100 formula B
wherein
W
1
: the total peak area within a molecular weight range of from 300 to 100000 on a gel permeation chromatogram of the partial hydrolysate of the fluorine-containing reactive silane,
W
2
: the total peak area within a molecular weight range of from 300 to 2 M on a gel permeation chromatogram of the partial hydrolysate of the fluorine-containing reactive silane, and
W
3
: the total peak area within a molecular weight range of from 6 M to 100000 on a gel permeation chromatogram of the partial hydrolysate of the fluorine-containing reactive silane.
BEST MODE FOR CARRYING OUT THE INVENTION
R
1
in the fluorine-containing reactive silane (hereinafter referred to as compound 1) is a hydrogen atom or a monovalent C
1-16
organic group. An organic group means a carbon-containing group, and the monovalent organic group preferably has from 1 to 8 carbon atoms.
The monovalent C
1-16
organic group may be an organic group having halogen atoms, functional groups or linking groups and is preferably a monovalent hydrocarbon group or a monovalent organic group having halogen atom(s) which may have functional group(s) or linking group(s).
The monovalent hydrocarbon group may be a monovalent aliphatic hydrocarbon group or a monovalent aromatic hydrocarbon group, preferably an aliphatic hydrocarbon group. As the monovalent aliphatic hydrocarbon group, an alkyl group, an alkenyl group or a cycloalkyl group, preferably an alkyl group, particularly preferably an alkyl group having at most 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group may be mentio
Gunji Fumiaki
Yoneda Takashige
Asahi Glass Company Limited
Tsoy Elena
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