EP0122771A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Tinted hydrogel plastic articles and method of tinting them
Assignee: Softint Inc
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Filing: 1984-04-10
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Granted: —
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Expires: 2004-04-10
Abstract
Abstract A hydrogel plastic article such as a soft contact lens is tinted by a water-insoluble vat dye which is physically locked into the hydrogel polymer as aggregates that are not individually discernible to the naked eye, and do not protrude beyond the surface of the article. In a soft contact lens, the aggregates may be concentrated near its convex face and only in an area approximating a human iris.
Inventors
- 👤 Nicholas M. Dacosta
- 👤 Miles W. Press
- 👤 Alan J. Touch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:12
CPC Classifications
B; B29; B29D; B29D11/00; B29D11/00865; B29D11/00894; B29D11/00903; B29D11/00009; B29D11/00038; G; G02; G02C; G02C7/00; G02C7/02; G02C7/021; G02C7/04; G02C7/046
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
48 words
A hydrogel plastic article which is tinted by water-insoluble particles of one or more vat dyes which are physically locked into the pores of the hydrogel as aggregates that are not individually descernible to the naked eye, and do not protrude beyond the surface of the plastic article.
Claim 2
Dependent Claim
48 words
A hydrogel plastic article which is tinted by water-insoluble particles of one or more vat dyes which are physically locked into the pores of the hydrogel as aggregates that are not individually descernible to the naked eye, and do not protrude beyond the surface of the plastic article.
Claim 3
Dependent Claim
20 words
A hydrogel plastic article as claimed in claim 1 wherein the vat dyes are anthraquinone, anthrone, indigoid, or thioindigoid dyes.
Claim 4
Dependent Claim
17 words
A hydrogel plastic article as claimed in claim 1 or 2 which is a soft contact lens.
Claim 5
Dependent Claim
17 words
A hydrogel plastic article as claimed in claim 3 which is tinted only adjacent its convex face.
Claim 6
Dependent Claim
38 words
A hydrogel plastic article as claimed in claim 4 which is untinted at the pupil area at the centre of the lens and at the edge of the lens, leaving an annular tinted area approximating a human iris.
Claim 7
Dependent Claim
33 words
A hydrogel plastic article as defined in claim 3, 4 or 5 wherein the vat dye aggregates are concentrated beneath the convex face within about 10% of the total thickness of the lens.
Claim 8
Dependent Claim
23 words
A hydrogel plastic article as defined in any of claims 3 to 6 wherein individual areas have been tinted with differently coloured dyes.
Claim 9
Dependent Claim
46 words
Process for producing a hydrogel plastic article as claimed in any of claims 1 to 7 which comprises impregnating pores of the hydrogel with a water-compatible dispersion of a solubilized leuco sulfate ester of a vat dye and precipitating an insoluble vat dye within those pores.
Claim 10
Dependent Claim
25 words
Process according to claim 8 wherein the hydrogel is rinsed after the pores have been impregnated and again after the vat dye has been precipitated.
Claim 11
Dependent Claim
28 words
Process according to claim 8 or 9 which comprises an initial step of dispersing a solubilized leuco sulfate ester of a vat dye to provide the water-compatible dispersion.
Claim 12
Dependent Claim
18 words
Process according to any of claims 8 to 10 wherein the said vat dye is precipitated by oxidation.
Claim 13
Dependent Claim
15 words
Process according to claim 11 wherein the oxidation is effected with an acidic oxidizing medium.
Claim 14
Dependent Claim
29 words
Process according to any one of claims 8 to 12 wherein the hydrogel is treated before or during the said impregnation to enlarge the pores in the said hydrogel.
Claim 15
Dependent Claim
22 words
Process according to claim 13 wherein the hydrogel is treated with a protic solvent to swell the pores of the said hydrogel.
Claim 16
Dependent Claim
25 words
Process according to any of claims 8 to 14 wherein the water-compatible dispersion is applied only to the convex face of a soft contact lens.
Claim 17
Dependent Claim
30 words
Process according to claim 15 wherein the centre and the edge of the lens are masked, thus leaving a clear edge around an annular tinted area approximating a human iris.
Claim 18
Dependent Claim
32 words
Process according to claims 15 or 16 wherein areas of the face of the lens are individually masked and water-compatible dispersions of differently coloured dyes are separately applied to different unmasked areas.
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AT101301B
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DE539468C
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AT245286B
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AT244629B
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CH437203A
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GB1547525A
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US4252421A
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