Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-02-17
2001-06-05
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S310000, C526S332000
Reexamination Certificate
active
06242551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polymeric colorant suitably used for coloring ocular lenses such as a contact lens, an intraocular lens and an artificial cornea, and a colored material for forming the ocular lenses, which uses the polymeric colorant.
2. Discussion of the Related Art
There have been proposed various polymeric colorants for coloring a composition or material which is used for forming a colored product. In the field of manufacture of an ocular lens such as a contact lens or an intraocular lens, for instance, a lens composition or material (lens-forming composition) used for producing the ocular lens is copolymerized with a suitable polymeric colorant, to thereby provide a colored material from which the intended ocular lens is produced. The ocular lens formed of such a colored material is uniformly colored and exhibits a high degree of resistance to exposure to light and chemical substances without suffering from decoloring or a change in its color, which would be caused by separation or elution of the colorant from the colored material.
JP-A-1-280464 discloses, as one example of the polymeric colorant for coloring the ocular lens, a polymeric colorant of azo-system or an azo-derived polymeric colorant wherein one of acryloyloxy, methacryloyloxy, vinyl, and aryl groups is substituted for at least one hydrogen atom of a naphthyl group which is bonded to an azo group. This polymeric colorant of the azo system is copolymerized with a vinyl monomer, to thereby provide a vinyl polymer from which the intended colored lens is produced.
JP-A-1-299560 discloses a colored ocular lens material obtained by copolymerizing a suitably selected copolymerizable lens-forming monomer component, a polymeric UV absorbent including a suitable polymeric group, and a polymeric colorant including a polymeric group which is selected from the group consisting of an acryloyl group, a methacryloyl group, a vinyl group, an aryl group, and an isopropenyl group. This colored ocular lens material does not suffer from elution of the UV absorbent and the colorant, and exhibits excellent durability. The colorant used in this ocular lens material is a polymeric colorant of azo system, wherein the polymeric group suitably selected from among those described above is introduced into a phenyl group or a naphthyl group bonded to the azo group, via an ester bond or an amide bond.
JP-A-8-503997 discloses a polymerizable yellow dye of azo system, wherein an unsaturated organic group having an ester structure or an amide structure is introduced into a phenyl group bonded to the azo group, via nitrogen or alkyl. This polymerizable yellow dye is polymerized with a lens-forming monomer component such as acrylate monomer or methacrylate monomer, to thereby provide a colored ocular lens material.
In those polymeric colorants described above wherein the polymeric unsaturated group is introduced via an oxygen atom into the aromatic ring in the phenyl or naphthyl group bonded to the azo group, the unsaturated group is bonded or attached to the aromatic ring by the ester bond formed therebetween. The polymeric colorant in which the ester bond is directly attached to the aromatic ring as described above tends to suffer from easy hydrolysis, whereby the colorant is chemically unstable, making its handling difficult. Further, the original color tone of the colorant undesirably changes due to the introduction of the polymeric group. In this case, it is difficult to predict the color tone of the colorant in the end product.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a novel polymeric colorant which is less likely to suffer from separation or elution, and is chemically stable without suffering from denaturation as caused by hydrolysis, while maintaining the original color tone, in spite of introduction of a suitably selected polymeric group therein.
It is a second object of the present invention to provide a colored ocular lens material having excellent characteristics, by using such a polymeric colorant.
The above-indicated first object of the invention may be attained according to a first aspect of the invention, which provides a polymeric colorant represented by the following formula:
A
1
—N═N—A
2
—O—(CH
2
)n—X
wherein, A
1
represents an aryl group which may have a substituent group, A
2
represents an arylene group which may have a substituent group, X represents one of an acryloyloxy group, a methacryloyloxy group, a vinylphenyl group, a vinylphenyloxy group, and a vinylphenylalkyloxy group whose alkyl portion has 1-5 carbon atoms, and n is an integer of 1-5.
In the polymeric colorant obtained according to the above first aspect of the present invention, the colorant per se includes a suitable polymeric group (X). This colorant is chemically bonded to a composition or material for an intended product, to thereby provide a suitable colored material for forming the intended colored product. The colored material obtained by using the present polymeric colorant is free from discoloration which would arise from the elution of the colorant, even when the colored material is boiled or immersed in water or organic solvents. In the present polymeric colorant, the suitable polymeric group (X) is introduced into the aromatic ring (A
2
) which bonds to the azo group, via the “—O—(CH
2
)
n
—” group, unlike the conventional colorants wherein the polymeric group is introduced via the ester bond. Accordingly, the present polymeric colorant is chemically stable without suffering from denaturation as caused by hydrolysis, assuring easy handling thereof. The colored material obtained by using the present polymeric colorant is capable of maintaining its color with high stability.
In the present polymeric colorant wherein the suitable polymeric group (X) is introduced into the aromatic ring (A
2
) via the “—O—(CH
2
)n—” group, the original color tone which derives from the colorant moiety is not changed by the introduced polymeric group. Accordingly, the polymeric colorant in the end product can maintain the original color with high stability. In addition, the polymeric group which is introduced into the aromatic ring (A
2
) can be suitably and freely selected from among various polymeric groups.
In a first preferred form of the above first aspect of the present invention, the aryl group is one of a phenyl group, a naphthyl group, a substituted phenyl group, and a substituted naphthyl group.
In a second preferred form of the above first aspect of the present invention, the arylene group is a phenylene group which has at least one substituent group or a naphthylene group which has at least one substituent group. preferably, the above-indicated at least one substituent group is selected from a group consisting of a hydroxyl group, a linear alkyl group having 1-6 carbon atoms, and a branched alkyl group having 1-6 carbon atoms.
The above-indicated second aspect of the present invention may be attained according to a second aspect of the present invention, which provides a colored material for an ocular lens, which is formed of a polymer obtained by copolymerizing at least one polymeric unsaturated monomer for the ocular lens and a polymeric colorant which is represented by the following formula:
A
1
—N═N—A
2
—O—(CH
2
)n—X
wherein, A
1
represents an aryl group which may have a substituent group, A
2
represents an arylene group which may have a substituent group, X represents one of an acryloyloxy group, a methacryloyloxy group, a vinylphenyl group, a vinylphenyloxy group, and a vinylphenylalkyloxy group whose alkyl portion has 1-5 carbon atoms, and n is an integer of 1-5.
In one preferred form of the above second aspect of the present invention, the polymeric colorant is used in an amount of 0.001-0.2 part by weight per 100 parts by weight of the above-indicated at least one unsaturated monomer for the ocular lens for copolymerization therewith.
REFERENCES:
patent: 5359439 (1994-10-01), Miller et al.
patent: 5470932 (1995
Niwa Kazuharu
Ojio Tatsuya
Tsuzuki Akira
Burr & Brown
Menicon Co. Ltd.
Pezzuto Helen L.
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