Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
2000-12-18
2004-01-20
Thibodeau, Paul (Department: 1773)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S220000, C428S328000, C428S329000, C428S330000, C428S331000, C428S332000, C428S446000, C428S447000, C428S448000, C428S926000, C524S261000, C524S492000, C524S430000, C524S497000
Reexamination Certificate
active
06680125
ABSTRACT:
THE INVENTION
The present invention relates to a coating composition for a hard coat layer of a plastic lens, a process for the preparation thereof, and a scratch-resistant plastic lens. More specifically, the present invention relates to a coating composition which is applied to a plastic lens surface for lending scratch resistance, etc., thereto and which is formable into a hard coat layer excellent in adhesion, a process for the preparation thereof, and a plastic lens which has a hard coat layer made of the above coating composition formed on a surface thereof and is excellent in scratch resistance, and the like.
PRIOR ART
As compared with glass lenses, plastic lenses, allyldiglycolcarbonate resin lenses in particular, are light in weight and excellent in safety, processability and cosmetics, and are coming rapidly to be popular owing to developments of an anti-reflection techniques and hard coating techniques in recent years. Further, there are under way developments of lenses made of thermoplastic resins having a smaller molding time and a smaller molding shrinkage than thermosetting resins such as an allyldiglycolcarbonate resin. Particularly, a lens made of a polycarbonate resin has come to be popular due to its excellent impact resistance.
While plastic lenses are widely used as described above, the plastic lenses have a defect that they are easily scratched or marred as compared with glass lenses.
For overcoming the above defect, it is recent practice to coat a plastic lens surface with a material having a high hardness. For example, U.S. Pat. No. 3,986,997, U.S. Pat. No. 4,309,319 and U.S. Pat. No. 4,436,851 disclose an abrasion resistant coating composition formed of a mixture of an alkoxysilane with colloidal silica. A cured coating of the above coating composition has excellent adhesion to an acrylic resin substrate. However, it does not at all adhere to some other plastic substrates, or it peels off due to a change with the passage of time even if it has excellent adhesion in the beginning.
For application to a plastic such as a polycarbonate, which is poor in adhesion to an organosiloxane-containing hard coating agent, it is general practice to use a primer. The use of the primer causes problems in productivity that a coating machine or equipment is complicated and that the step of coating takes a longer time period, so that there has been desired a direct application method that can be carried out without any treatment with a primer.
As a method of direct application to a polycarbonate without any treatment with a primer, several methods have been proposed in JP-A-7-90224, and the like. In these methods, however, dyeing which is characteristic of a plastic lens is almost impossible. Further, when a general dipping method is employed for the application, interference fringes are caused by a difference between the refractive index of a polycarbonate and that of a hard coating film, which is undesirable in view of an appearance.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a coating composition for a hard coat layer, which coating composition overcomes the above defects of the prior art and can form a scratch-resistant hard coat layer having excellent adhesion to plastic lenses such as a Polycarbonate lens without using any primer, and having transparency and excellent dyeability, by a general application method, and a method of preparation thereof. It is also an object of the present invention to provide a scratch-resistant plastic lens having a coating formed by applying the above coating composition.
For achieving the above objects, the present inventor has made diligent studies and as a result has found that a composition containing, as essential components, a hydrolyzate of an organosilicon compound having a specific structure, specific metal oxide fine particles, a polyurethane and a curing agent can give a hard coat layer which not only has sufficient adhesion, dyeability and flexibility but also has excellent scratch resistance (abrasion resistance) when applied onto a plastic lens surface and cured under heat. On the basis of the above finding, the present invention has been completed.
That is, according to the present invention, there is provided a coating composition for a hard coat layer of a plastic lens, which comprises, as essential components, (A) a hydrolyzate of an organosilicon compound of the general formula (I),
wherein R
1
is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a monovalent organic group having a mercapto group, an amino group, a methacryloxy group or an epoxy group, R
2
is an alkyl group having 1 to 4 carbon atoms, R
3
is an alkyl group having 1 to 10 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms or an acyl group having 2 to 10 carbon atoms, n is 0 or 1 and a plurality of (OR
3
)s may be the same or different, (B) at least one kind of fine particles selected from fine particles of oxides of silicon, aluminum, tin, antimony, zirconium, tungsten and titanium and composite fine particles of at least two oxides of these, (C) a polyurethane and (D) a curing agent.
According to the present invention, further, there is provided a method of preparation of a coating composition for a hard coat layer of a plastic lens, which comprises mixing an organosilicon compound of the general formula (I) which is a precursor of the above component (A) with a polyurethane as the above component (C) optionally together with a solvent, hydrolyzing the organosilicon compound, thereby obtaining a homogeneous solution of a hydrolyzate of the organosilicon compound of the above general formula (I) as the above component (A) and the polyurethane as the component (C), and then adding the fine particles as the component (B) and the curing agent as the component (D).
According to the present invention, further, there is provided a scratch-resistant plastic lens having a hard coat layer formed of the above coating composition on a surface thereof.
BEST MODE FOR PRACTICING THE INVENTION
In the coating composition of the present invention, a hydrolyzate of an organosilicon compound of the general formula (I) is used as component (A).
In the above general formula (I), R
1
is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a monovalent organic group having a mercapto, amino, methacryloxy or epoxy group. The above alkyl group, alkoxy group and alkenyl group may be linear, branched or cyclic. Examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, cyclopentyl and cyclohexyl groups. Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, allyl, propenyl, butenyl and hexenyl groups. Examples of the alkoxy group having 1 to 10 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, hexoxy, octoxy, cyclopentoxy and cyclohexoxy groups. Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl and naphthyl groups. Examples of the aralkyl group having 7 to 10 carbon atoms include benzyl and phenetyl groups. Further, the monovalent organic group having a mercapto, amino, methacryloxy or epoxy group is preferably an alkyl group having 1 to 6 carbon atoms and having the above substituent, and specific examples thereof include &ggr;-mercaptopropyl, &ggr;-aminopropyl, &ggr;-methacryloxypropyl, &ggr;-glycidoxypropyl and 3,4-epoxycyclohexyl groups.
R
2
is an alkyl group having 1 to 4 carbon atoms, and the alkyl group may be linear or branched. Examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl groups. R
3
is an alky
Ahmed Sheeba
Frishauf Holtz Goodman & Chick P.C.
Hoya Corporation
Thibodeau Paul
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