Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2000-11-15
2002-12-31
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S429000, C428S446000, C428S447000, C428S450000, C427S402000, C106S013000, C106S014050
Reexamination Certificate
active
06500553
ABSTRACT:
The present invention relates to a substrate having treated surface layers, on which water drops scarcely attached or from which attached water drops can easily be removed, and a process for producing it.
Various substrates having treated surface layers are used in various fields, and adverse effects brought about by water on the surface of such substrates are problematic.
For example, in transportation equipments such as electric cars, automobiles, ships or aircrafts, the surface of 1) an exterior part such as an outer panel, a window glass, a mirror or a display surface material, 2) an interior part such as an instrument panel, or 3) other articles, is desired to be always clean. If e.g. raindrops, dusts or soils are deposited on the surface of an article in a transportation equipment, or moisture is condensed thereon due to the temperature or humidity in the air, basic functions of the article in a transportation equipment may be impaired in some cases.
Especially in a case where the article for a transportation equipment is an article for which transparency or see-through property is required (such as a window glass or a mirror), a deterioration of the transparency or see-through property due to attachment of e.g. raindrops, dusts or soils, or concentration of moisture, may impair the purpose intended by the article. For example, on a windshield of an automobile, transparency and see-through property may be impaired due to e.g. attachment of e.g. raindrops.
Means to physically remove water drops (such as removal by wiping off or by means of a wiper) may sometimes impart fine scratch marks on the surface of an article. Further, such scratch marks may sometimes be widened by foreign particles accompanying such water drops. Furthermore, it is well known that when moisture is attached to a glass surface, glass components are likely to elute into the moisture, whereby the surface will be eroded, thus leading to so-called scorching. If the surface is strongly polished or abraded to remove such scorching, a fine roughness is likely to form. At the see-through portion made of glass having substantial scorching or a fine roughens on its surface, its basic function is lowered, and scattering of light on its surface tends to result.
Further, moisture is likely to give a hazardous influence to the surface or the inside of e.g. an article for a transportation equipment and to promote damages, soiling, yellowing or corrosion. Otherwise they may induce a change in the electrical characteristics, the mechanical properties or the optical properties of the article for a transportation equipment. Further, the appearance of such an article may be impaired in some cases, and if it is a surface which is directly visually observed or which is directly touched by a person, the impairment in appearance may give a filthy impression.
Adverse effects of this type due to water are problematic not only in the field of articles for transportation equipments but also in various fields including articles for building or building decoration or articles for electric or electronic equipments.
Under these circumstances, it is strongly desired to impart to the substrate surface a characteristic such that water drops scarcely attach to the substrate surface or attached water drops can easily be removed (hereinafter referred to simply as a water drop removal property). Heretofore, to impart a water drop removal property to a surface, surface treating agents for direct application to the surface of an article, such as a silicone wax, a silicone oil made of organopolysiloxane and a surfactant, have been proposed.
JP-A-58-147484, JP-A-60-221470 and JP-A-4-96935 disclose that a polysiloxane and a polysilazane having a perfluoroalkyl group are excellent in water repellency.
However, they are poor in abrasion resistance and weather resistance, and could not be used outdoors for a long period of time. Further, for e.g. a windshield of an automobile or a window glass for building, not only water repellency but also such a characteristic that water drops roll down on its surface (water drop rolling property) is required. However, they do not necessarily have adequate water drop rolling property.
Further, JP-A-10-194784 proposes a water repellent glass which comprises a glass plate, a base film made of a silicon oxide having part of oxygen atoms replaced with hydroxyl groups, and an organic silicon compound containing a fluoroalkyl group.
The above water repellent glass is excellent in abrasion resistance, but is poor in weather resistance practically. Further, the water drop rolling property is not sufficient.
Further, JP-A-7-252472 discloses a water repellency agent containing a co-hydrolyzate of a perfluoroalkyl group-containing organic silicon compound and a hydrolyzable group-containing methylpolysiloxane. This is obtained by co-hydrolyze a perfluoroalkyl group-containing organic silicon compound which is excellent in water repellency and a hydrolyzable group-containing methylpolysiloxane which is excellent in water drop rolling property, in water and a hydrophilic solvent, so as to obtain one which is excellent in both water repellency and water drop rolling property.
However, if the above water repellency agent is coated on a substrate, until it completely gets dry, the perfluoroalkyl group-containing organic silicon compound having a low surface energy tends to move outside the hydrolyzable group-containing methylpolysiloxane having a high surface energy, and no desired water drop rolling property intended by the latter tends to be obtained.
Further, many of surface treating agents which have conventionally been proposed require a pre-treatment accompanying coating, and the coating tends to be nonuniform. Further, the adhesion of the treating agents themselves to the substrate is low, and their water drop removal property can not be maintained for a long period of time. Thus, the range of their application has been limited.
Further, it is desired to develop a means of imparting such water drop removal property not only to substrates to be produced anew but also to substrates which have already been used. In such a case, the surface treating agent must be capable of imparting water drop removal property simply by directly coating such substrates with the surface treating agent at room temperature. For example, when it is attempted to apply a treatment of imparting water drop rolling property to a windshield for an automobile which has already been used, it is impossible to replace the windshield of each automobile from the economical reason, and it is practically impossible to subject the portion to baking after coating. Accordingly, with conventional means using a surface treating agent, such a treatment is difficult.
Under these circumstances, the present invention has been made to overcome the above problems. Namely, the present inventors have conducted studies on a treating agent which will overcome conventional problems, and have found a means of surface treatment which can be applied to a variety of substrates, and which will impart long lasting excellent water drop removal property (water drop rolling property and water repellency). They have further found that said treatment can be carried out easily, and that the substrate thus treated, having water drop removal property, is particularly suitable as a substrate for a transportation equipment. The present invention has been accomplished on the basis of these discoveries.
It is an object of the present invention to provide a substrate which has water drop removal property, which is excellent in abrasion resistance, weather resistance, boilproof property and chemical resistance, and whose characteristics thereby last semipermanently.
The present invention provides a substrate having at least two treated surface layers, wherein the first layer constituting the outermost layer among the treated surface layers is a layer formed by covering with a composition containing a reactive silicon-containing compound (I) which forms a surface having a rolling angle of at
Gunji Fumiaki
Hamano Tadashi
Yoneda Takashige
Asahi Glass Company Limited
Dawson Robert
Feely Michael J
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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