Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1998-12-22
2001-02-20
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S331000, C428S429000, C428S448000, C428S451000, C428S452000, C548S110000, C548S261000, C554S039000, C556S419000
Reexamination Certificate
active
06190777
ABSTRACT:
TECHNICAL FIELD
Generally, there have been employed two methods for providing a substrate such as a glass sheet with ultraviolet absorbing properties, one of which to coat a substrate with an ultraviolet absorbing material and the other of which to utilize multi-reflections of a multilayer. The latter is excellent in free adjustability of wavelength to be shielded and capability of clear-cutting, but has a problem relating to cost due to the complicated production processes. In the former method, there may be used an inorganic or organic ultraviolet absorber.
Inorganic ultraviolet absorbers as disclosed in Japanese Patent Laid-Open Nos. 5-339033, 5-345639 and 6-56466 are excellent in resistance to weathering and resistance to heat but are disadvantageous because these absorbers are less selective because the wavelength of ultraviolet to be absorbed is determined by the band gap of a compound forming the absorbers and none of these can cut off ultraviolet rays of wavelengths of neighborhood of 400 nm. Furthermore, most of the absorbers are involved with unexpected coloration upon interception of ultraviolet rays of longer wavelength.
On the contrary, organic ultraviolet absorbers are broad in range of absorptivity and thus can absorb ultraviolet in a wide range of wavelengths by selecting the type, concentration and thickness of the absorbers. As a result of extensive research directed to a system having such organic ultraviolet absorbers, it has now been found that use of an absorber which has a maximum absorption wavelength in a longer wavelength region or which is increased in concentration or in layer thickness is conducive to intercept ultraviolet in a longer wavelength region. However, such an absorber having the maximum absorption wavelength in a longer wavelength region as disclosed in Japanese Laid-Open Publication No. 6-145387 is poor in resistance to a light and reduced in absorbing power with the lapse of time. This absorber also has a problem that the permeability is easily deteriorated due to use of a fluorescent bleach.
A benzophenic- or benzotriazolic absorber is relatively good in resistance to a light and capable of absorbing ultraviolet rays in a relatively longer wavelength by increasing the concentration and the layer thickness. However, in the case of coating these absorbers mixed with a resin over a substrate, the layer formed thereover is limited in thickness to an extent of several tens of micrometers. However, with the layer of the mixture in this order of thickness, it is necessary to add the absorbers in a considerably high concentration. Still, the mere addition of the absorbers in a high concentration leads to problems involving deposition thereof and bleedout due to the use over an extended period of time.
It has been attempted for solving these problems to react an absorber with a resin in which instance the absorber is copolymerized with an acrylic resin, as disclosed in Japanese Patent Laid Open Publication Nos. 2-248412 and 6-88064. However, since the acrylic resin per se has a drawback in resistance to weathering and heat, the resulting ultraviolet absorber can not bear to be used over a prolonged length of time. Alternatively, various researches have been made on the possibility of using an ultraviolet absorber which is reactive a silicone resin excelled in resistance to weathering and resistance to heat as disclosed in Japanese Patent Laid-Open Publication No. 61-54800, 2-117928 and 3-45094. It, however, has been found that most of such absorbers have a difficulty in synthesis in technical view and a problem in durability.
An object of the present invention is to provide an ultraviolet absorbing material which is easy for synthesis and free from bleedout of the ultraviolet absorber even after use of a prolonged period of time and from the foregoing deficiencies even in the case where a long wavelength interception can be achieved in the presence of the absorber in a high concentration. Another object of the present invention is to provide an ultraviolet absorbing plate which is excellent in resistance to weathering as well as resistance to heat, free from bleed out after being used for an extended period of time and capable of intercepting ultraviolet rays in a longer wavelength region without reducing transmittance of ultraviolet in a visible region. Disclosure of the Invention
According to the invention, there is provided an ultraviolet absorbing material comprising a reaction product of (a) an aminosilane compound of formula (1) or the derivative thereof with (b) an ultraviolet absorber having in its molecules a carboxyl group so as to form amide bonds derived from the aminosilane compound or the derivative thereof,
formula (1) being represented by
wherein R
1
is a C
1
-C
10
alkylene group or a divalent group of the formula —(CH
2
)m—NH— in which m is an integer of 1-4, R
2
may be the same or different and each are selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, a C
1
-C
10
alkyl group and a C
1
-C
10
alkoxy group provided that at least one of R
2
is an alkoxy group, and n is an integer of 0 or greater.
An ultraviolet absorbing plate according to the invention is produced by forming the ultraviolet absorbing layer of an ultraviolet absorbing material having an amide bond and an Si—O bond, on a substrate.
The ultraviolet absorbing material comprises preferably a reaction product of (a) an aminosilane compound of formula (1) or the derivative thereof with (b) an ultraviolet absorber having in its molecules a carboxyl group so as to form amide bonds derived from the aminosilane compound or the derivative thereof,
formula (1) being represented by
wherein R
1
is a C
1
-C
10
alkylene group or a divalent group of the formula —(CH
2
)m—NH— in which m is an integer of 1-4, R
2
may be the same or different and each are selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, a C
1
-C
10
alkyl group and a C
1
-C
10
alkoxy group provided that at least one of R
2
is an alkoxy group, and n is an integer of 0 or greater.
The reaction between the aminosilane compound or the derivative and the ultraviolet absorber having in its molecule a carboxyl group is preferably conducted in the presence of a silicone resin or is conducted, followed by addition of a silicone resin upon completion of the reaction.
The ultraviolet absorbing material is preferably produced by reacting (a) an aminosilane compound of formula (1) or the derivative thereof with (b) an ultraviolet absorber having in its molecules a carboxyl group in the presence of a silane compound having an epoxy group and/or a colloidal silica so as to form an amide bond derived from the aminosilane compound or by adding a silane compound having an epoxy group and/or a colloidal silica to a reaction product obtained by reacting (a) an aminosilane compound of formula (1) or the derivative thereof with (b) an ultraviolet absorber having in its molecules a carboxyl group so as to form an amide bond derived from the aminosilane compound,
formula (1) being represented by
wherein R
1
is a C
1
-C
10
alkylene group or a divalent group of the formula —(CH
2
)m—NH— in which m is an integer of 1-4, R
2
may be the same or different and each are selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, a C
1
-C
10
alkyl group and a C
1
-C
10
alkoxy group provided that at least one of R
2
is an alkoxy group, and n is an integer of 0 or greater.
The substrate is preferably transparent and the ultraviolet absorbing layer is also preferably transparent.
The substrate preferably comprises a plurality of transparent substrates laminated one after another and one or more the ultraviolet absorbing layers interposed therebetween.
An overcoat layer is preferably coated over the ultraviolet absorbing layer.
The substrate has preferably a transparent electrically conductive layer on the side where the ultraviolet absorbing layer is disposed.
An overcoat layer is preferably disposed betwe
Asano Tuyoshi
Minami Masaki
Nishikitani Yoshinori
Takaesu Noboru
Akin Gump Strauss Hauer & Feld L.L.P.
Nakarani D. S.
Nippon Mitsubishi Oil Corporation
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