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GB2270576A - Method for producing photochromic plastic lens - Google Patents

Method for producing photochromic plastic lens Download PDF

Info

Publication number
GB2270576A
GB2270576A GB9315620A GB9315620A GB2270576A GB 2270576 A GB2270576 A GB 2270576A GB 9315620 A GB9315620 A GB 9315620A GB 9315620 A GB9315620 A GB 9315620A GB 2270576 A GB2270576 A GB 2270576A
Authority
GB
United Kingdom
Prior art keywords
plastic lens
photochromic dye
photochromic
dye solution
lens
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9315620A
Other versions
GB9315620D0 (en
Inventor
Nori Y C Chu
Jon Haglund
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
American Optical Corp
Original Assignee
American Optical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Optical Corp filed Critical American Optical Corp
Publication of GB9315620D0 publication Critical patent/GB9315620D0/en
Publication of GB2270576A publication Critical patent/GB2270576A/en
Withdrawn legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00Producing optical elements, e.g. lenses or prisms
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G02B1/041Lenses
    • GPHYSICS
    • G02OPTICS
    • G02CSPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00Optical parts
    • G02C7/02Lenses; Lens systems ; Methods of designing lenses
    • G02C7/021Lenses; Lens systems ; Methods of designing lenses with pattern for identification or with cosmetic or therapeutic effects

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  • Physics & Mathematics (AREA)
  • Ophthalmology & Optometry (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • General Health & Medical Sciences (AREA)
  • Eyeglasses (AREA)
  • Surface Treatment Of Optical Elements (AREA)
  • Coloring (AREA)
  • Optical Filters (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)

Abstract

A photochromic property is imparted to a plastic lens at high temperatures by microwave heating the lens in a solution of a photochromic dye or in contact with a plastic film containing the dye.

Description

2270576 METHOD FOR PRODUCING PHOTOCHROMIC PLASTIC LENS The present
invention relates to photochromic plastic lenses. More particularly, the present invention relates to a fast and efficient method for producing photochromic lenses by microwave heating.
Photochromic materials have many potential applications in the fields of self-developing photography, dosimetry, optical signal processing, data display, decoration, control of radiation intensity and others. The most widely used and commercially successful photochromic material technology is in eyewear for protecting against sunlight and controlling of sunlight intensity. Currently, the majority of the photochromic eyewear lenses are made of silver halide based glasses. However, photochromic plastic lenses based on spirooxazine photochromic compounds have made some inroad.
The spirooxazine compounds are a member of a family of photochromic compounds with inherently excellent photo- durability. They are the preferred photochromic compounds used for producing eyewear glasses (both ophthalmic and sunglass lenses). This is due to their photo-fatigue resistance and their colourless hue in the unactivated form (i.e., in the absence of the activating ultraviolet light).
Many methods are known to impart to the photochromic property to a material. The commonly used methods include dyeing, casting, coating and injection molding. The method of application depends strongly on the substrate material.
For example, the spirooxazine dyes are sensitive to certain chemicals such as polymerization initiators and oxidants, and are unstable at high temperatures (e.g., at injection molding temperatures).
The commonly used plastics for eyewear included poly(methyl methacrylate) (PMMA), cellulose acetate butyrate (CAB), polycarbonate, and cellulose acetate propionate (CAP) and diethylene glycol bis (allyl 2 carbonate) (CR-39). The first four are thermoplastics while CR-39 is a thermoset plastic. Since the methods for photochromic treatment depend on the nature of the lens substrate, some methods applicable to the thermoplastics may not be useful for the thermoset plastics. For example, the photochromic dye cannot be mixed into CR-39 monomer to be polymerized along with the monomers to obtain a product with the dye uniformly dispersed, since the polymerization catalyst will destroy the dye.
The dyeing process is generally performed in a high boiling organic solvent bath. The solvents commonly used are alcohols, glycols, aromatic or aliphatic hydrocarbons. The thermoset plastic lens is immersed in the solvent bath which normally contains between 1% to 10% photochromic dye.
The dye bath is maintained in the range of 900 to 1200C and the immersion time is normally one to several hours. This will ensure that an adequate amount of dye is diffused into the lens surface for sufficient photochromic durability. Thermal stability of the dye in the dyeing bath is a major problem because of the cost associated with high dye concentration and long dyeing time.
Two other known processes for application of photochromic dye to the surfaces of a lens include vaporliquid phase transfer and solid phase transfer. In the vapor-liquid phase transfer, the lens is heated in the presence of vapours of photochromic dye. In the solid phase transfer, the photochromic dye and a film-forming resin are dissolved in a solvent. The resulting solution is applied to the surface of a lens by any of the commonly used techniques such as dipping, spinning or spraying. The coated lens is heated to a high temperature below the melting point of the dye for a sufficient length of time to allow diffusion of the dye from the resin film to the lens substrate. Generally, the heating temperature is in the range of 1100 to 1500C from several minutes to hours depending on the hardness of the lens. After the heat 3 treatment step, the resin-film is removed. The heating source for these two photochromic processes is a conventional heat oven.
Heating by conventional ovens is convenient, but not cost effective, especially for hard cured lenses. To obtain adequate amounts of dye transferred to the lens, several hours of heating time is required.
The object of the present invention is to propose a more efficient method for producing photochromic plastic lenses. The object is achieved by the method for producing photochromic plastic lenses of the present invention as claimed in claim 1. In accordance with the present invention, a photochromic property is imparted to a plastic lens (e.g., by dyeing the surface of the lens with a photochromic dye solution) at high temperature by microwave heating for a predetermined amount of time.
The microwave heating, in accordance with the present invention, considerably reduces the heating time as compared to the convection heating used by the prior art.
Accordingly, the microwave heating results in an efficient, cost effective method for producing photochromic plastic lenses.
The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description.
A novel method for producing a photochromic plastic lens is presented. The plastic lens is comprised of any optical grade plastic material, such as poly(methyl methacrylate) (PMMA), cellulose acetate butyrate (CAB), polycarbonate, cellulose acetate propionate (CAP) or diethylene glycol bis(allyl carbonate) (CR-39). The first four are thermoplastics while CR-39 is a thermoset plastic. Other plastic materials having a refractive index greater than CR-39 have been developed for eyewear application. For 4 example, CR-400s materials from PPG and MR-6 from Mitsui Toatsu.
As was noted in the prior art, spirooxazine photochromic compounds are being used for photochromic plastic lenses and such is contemplated by the present invention. The spirooxazine compounds are a member of a family of photochromic compounds with inherently excellent photo-durability. They are the preferred photochromic compounds used for producing eyewear glasses (both ophthalmic and sunglass lenses). This is due to their photo-fatigue resistance and their colourless hue in the unactivated form (i.e., in the absence of the activating ultraviolet light). Representative spirooxazine family of photochromic compounds can be classified into several subclasses, which are spiroindolinonaphthoxazines (NISO), spiroindolinopyridobenzoxazines (QISO), spiroindolinobenzoxazines (BISO) and spiroindolinoanthryloxazines (AISO).
In accordance with the present invention a photochromic property is imparted to the lens by dyeing the lens in photochromic dye solution. The lens is immersed in the photochromic dye solution which is then heated for a predetermined amount of time. After heating the lens may remain in the heated photochromic dye solution to seek. The lens is then removed and washed with a solvent.
The heat treatment step is accomplished by microwave heating. The microwave heating has been found to be very efficient and cost effective as compared to the prior art method. The heat treatment step in the prior art was accomplished by conventional heating. Heat treatment using the conventional ovens required a heating temperature in the range of 1100 to 1500C (for CR-39 lenses) for several minutes to hours depending on the hardness of the lens. Heating by a conventional oven is convenient, but not cost effective especially for hard high cured lenses. To obtain an adequate amount of dye transferred to the lens, several hours of heating time is required. Microwave heating, in accordance with the present invention, considerably reduces the heating time as can be seen from the examples provided below.
The lenses used in the below examples were high cured (ú71K 1 A0lite 4CR-39 plano lenses having a diameter of 76 mm (manufactured by American Optical Corporation, the assignee of the present invention). The photochromic dye used was a mixture of 1,3,3,4,5- and 1,3,3,5,6-pentaTaethyl-91-methoxy NISO isomer mixture. Further, in order to determine the amount of dye being transferred to the lens substrate, the absorbencies of the lens at 360 nm was measured before and after photochromic treatment.
Example 1
In a first prior art example, 1.2 kg of propylene glycol was added in a 1. 5 L glass beaker. The solvent was heated to 1150C with a hot plate. Twenty-four (24) g of CRTM) photochromic dye were added to the solvent. Two A0lite4 lenses were used, one lens was immersed in the dye bath for 20 1 hour and the other 2 hours. The absorbence change at 360 nm before and after treatment for the first lens (i.e., 1 hour treatment) was 0,18 and for the second lens (i.e., 2 hour treatment) was 0.25.
Example 2
In a second prior art example, a 2% dye bath solution was made in a metal pan and heated to 1520C by a hot plate.
Two A0lite41enses were dyed by immersing them in the dye bath for 1 hour. The dye uptake as measured by the absorbence change at 360 nm was 0.46 for both lenses.
Example 3
In a first example in accordance with the present invention, a 1 L glass beaker containing 500 g propylene glycol and 10 g photochnomic dye was placed in a microwave ORIrmi oven (e.g., Goldstai/7, 800 watt model) with a lens therein and heated f or 6 minutes. The lens was then soaked in the heated solution for 15 minutes. The lens was then removed 6 and washed with acetone. The temperature of the solution after heating was 1670C. The absorbence change of the lens at 360 nm was 0.37. Example 4 5 In a second example in accordance with the present invention, 5 g more dye was added to the solution of Example 3 to make a 3% dye solution. A lens was dyed by immersing it in the solution and-heating the solution with the lens therein for 6 minutes, using the microwave oven.
The lens was then removed and washed with acetone. The absorbence change of the lens at 360 nz was 0.60.
The method of the present invention obtains comparable results to that of the prior art in significantly less time. This is clearly seen by comparing the time requires in the prior art examples 1 and 2 to examples 3 and 4 which are in accordance with the present invention.
While the preferred method of imparting the photochromic property to the lens is dyeing, other known methods, such as casting, coating and injection molding may be employed. The method of application is dependent on the lens material used. For example, spirooxazine dyes are sensitive to certain chemicals, such as polymerization initiators and oxidants, and are unstable at high temperatures (e.g., at injection molding temperatures).
Further, some methods applicable to the thermoplastics may not be useful for the thermoset plastics. For example, the photochromic dye cannot be mixed into CR-39 monomer to be polymerized along with the monomers to obtain a product with the dye uniformly dispersed since the polymerization catalyst will destroy the dye.
Alternately, the aforementioned solid phase transfer process for applying the photochromic dye to the surface of the lens may be used in the method of the present invention. In the solid phase transfer, the photochromic dye and a film-forming resin are dissolved in a solvent. The resulting solution is applied to the surface of a lens 7 by any of the commonly used techniques such as dipping, spinning or spraying. The coated lens is then heated to a high temperature below the melting point of the dye for a sufficient length of time to allow the diffusion of the dye 5 from the resin film to the lens substrate.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention has been described by way of illustrations 10 and not limitation.
8

Claims (21)

1. A process for producing a photochromic plastic lens, including the steps of:
mixing a photochromic dye solution; immersing a plastic lens in said photochromic dye solution; characterised by microwave heating the photochromic dye solution with the plastic lens therein for a predetermined amount of time; removing the plastic lens from the heated photochromic dye solution after a predetermined amount of time has elapsed; and washing the plastic lens with a solvent.
2. The process of claim 1, characterised in that said photochromic dye solution comprises a spirooxazine compound.
3. The process of claim 2, characterised in that said spirooxazine compound comprises spiroindolino naphthoxazines, spiroindolinopyridobenzoxazines, spiroindolino-benzoxazines or spiroindolino- anthryloxaziones.
4. The process of any of the claims 1 to 3, characterised in that said step of microwave heating comprises microwave heating using a microwave oven.
5. The process of any of the claims 1 to 4, characterised in that said plastic lens comprises a thermoplastic or a thermoset plastic.
6. The process of any of the claims 1 to 5, characterised in that said plastic lens comprises poly(methyl methacrylate) (PMMA), cellulose acetate butyrate (CAB), polycarbonate, cellulose acetate propionate (CAP) or diethylene glycol bis(allyl carbonate) (CR-39).
7. The process of any of the claims 1 to 6, characterised in that said photochromic dye solution includes from about 1% to about 10% of a photochromic dye. 35
8. A process of any of the claims 1 to 7, characterised by the additional steps of soaking the plastic lens in the
9 microwave heated photochromic dye for a predetermined amount of time and removing the plastic lens f rom the heated photochromic dye solution after the predetermined amount of time for soaking has elapsed. 5 9. A process for producing a photochromic plastic lens, characterised by the steps of: coating the surface of a plastic lens with a photochromic dye solution; microwave heating the coated plastic lens for a predetermined amount of a time, whereby a photochromic dye is diffused from a resin film to the surface of the plastic lens; and removing the resin film.
10. The process of claim 9, characterised in that said step of coating comprises dipping the lens in the photochromic dye solution.
11. The process of claim 9, characterised in that said step of coating comprises spin coating the surf ace of the plastic lens with the photochromic dye solution. 20
12. The process of claim 9, characterised in that said step of coating comprises spraying the surface of the plastic lens with the photochromic dye solution.
13. The process of any of the claims 9 to 12, characterized in that said plastic lens comprises a thermoplastic or a thermoset plastic.
14. The process of any of the claims 9 to 13, characterised in that said plastic lens comprises poly(methyl methacrylate) (PMMA), cellulose acetate butyrate (CAB), polycarbonate, cellulose acetate propionate (CAP) or diethylene glycol bis(allyl carbonate) (CR-39).
15. The process of any of the claims 9 to 14, characterised in that said photochromic dye solution comprises said photochromic dye and said resin dissolved in a solvent.
16. The process of claim 15, characterised in that said photochromic dye comprises a spirooxazine compound.
17. The process of claim 16, characterised in that said spirooxazine compound comprises spiroindolino naphthoxazines, spiroindolinopyridobenzoxaines, spiro indolinobenzoxazines or spiroindolinoanthryloxazines.
18. The process of claim 15, characterised in that said solvent comprises an alcohol, a glycol, an aromatic hydrocarbon or an aliphatic hydrocarbon.
19. The process of any of the claims 9 to 18, characterised in that said step of microwave heating comprises microwave heating using a microwave oven.
20. The process of any of the claims 9 to 19, characterised in said step of removing comprises removing the resin film using a solvent.
21. A process substantially as hereinbefore described.
1
GB9315620A 1992-09-11 1993-07-28 Method for producing photochromic plastic lens Withdrawn GB2270576A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US94421592A 1992-09-11 1992-09-11

Publications (2)

Publication Number Publication Date
GB9315620D0 GB9315620D0 (en) 1993-09-08
GB2270576A true GB2270576A (en) 1994-03-16

Family

ID=25481008

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9315620A Withdrawn GB2270576A (en) 1992-09-11 1993-07-28 Method for producing photochromic plastic lens

Country Status (10)

Country Link
JP (1) JPH06108384A (en)
KR (1) KR940006752A (en)
CN (1) CN1093813A (en)
BR (1) BR9302073A (en)
CA (1) CA2095703A1 (en)
DE (1) DE4328675A1 (en)
FR (1) FR2695732A1 (en)
GB (1) GB2270576A (en)
IL (1) IL105147A0 (en)
MX (1) MX9302645A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995010790A1 (en) * 1993-10-15 1995-04-20 Ppg Industries, Inc. High refractive index photochromic ophthalmic article
WO2000014325A1 (en) * 1998-09-03 2000-03-16 Ryser Christophe U Tinting plastic articles
EP2105766A3 (en) * 2008-03-26 2014-02-19 Hoya Lens Manufacturing Philippines Inc. Dyeing method for plastic lens

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE277360T1 (en) * 1999-08-02 2004-10-15 Essilor Int METHOD FOR PRODUCING CROSS-LINKED, TRANSPARENT, HYDROPHILIC AND PHOTOCHROMIC PLASTIC MATERIALS AND OPTICAL AND OPTHALMIC OBJECTS
KR100379257B1 (en) * 2000-04-27 2003-04-08 주식회사 듀얼인텍 Photochromic resin and producing method of the same
US20030164563A1 (en) * 2002-03-04 2003-09-04 Olin Calvin Use of microwave energy to disassemble, release, and hydrate contact lenses
KR20040011703A (en) * 2002-07-30 2004-02-11 주식회사 유진텍 이십일 A Process For Producing Photochromic Lens
KR20040011702A (en) * 2002-07-30 2004-02-11 주식회사 유진텍 이십일 A Coating Composition For Photochromic Contact Lens
KR20040011701A (en) * 2002-07-30 2004-02-11 주식회사 유진텍 이십일 A Coating Composition For Plastic Photochromic Lens
US7175675B2 (en) * 2003-12-11 2007-02-13 Bayer Materialscience Llc Method of dyeing a plastic article
KR100649348B1 (en) * 2006-03-30 2006-11-28 (주)유브이테크인터내셔날 Spectacle Lens Dyeing Method with Photochromic Compatibility
CN103091866A (en) * 2012-12-18 2013-05-08 上海甘田光学材料有限公司 Penetration type photochromic lens and manufacturing method thereof
KR102102929B1 (en) * 2019-09-20 2020-04-22 (주)자이언 coating apparatus and method using microwave

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4289497A (en) * 1980-09-02 1981-09-15 American Optical Corporation Gradient photochromic lens and method selectively reducing photochromic activity
GB2174711A (en) * 1985-03-29 1986-11-12 Ppg Industries Inc Production of synthetic plastics articles

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US4043637A (en) * 1973-06-15 1977-08-23 American Optical Corporation Photochromic light valve
FR2415318A1 (en) * 1978-01-18 1979-08-17 Essilor Int PROCESS FOR THE INTEGRATION OF A PHOTOCHROMIC SUBSTANCE INTO A BASE SUBSTRATE TRANSLUCENT IN ORGANIC MATTER, AND BASIC TRANSPARENT SUBSTRATE
GB8432563D0 (en) * 1984-12-21 1985-02-06 Banks P J Apparatus for handling information
JPS6210605A (en) * 1985-07-09 1987-01-19 Seiko Epson Corp Photochromic optical materials
US4880667A (en) * 1985-09-24 1989-11-14 Ppg Industries, Inc. Photochromic plastic article and method for preparing same
US5130353A (en) * 1990-03-07 1992-07-14 Ppg Industries, Inc. Method for preparing photochromic plastic article
JPH03269507A (en) * 1990-03-20 1991-12-02 Nippon Sheet Glass Co Ltd Plastic lens having dimming property

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4289497A (en) * 1980-09-02 1981-09-15 American Optical Corporation Gradient photochromic lens and method selectively reducing photochromic activity
GB2174711A (en) * 1985-03-29 1986-11-12 Ppg Industries Inc Production of synthetic plastics articles

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995010790A1 (en) * 1993-10-15 1995-04-20 Ppg Industries, Inc. High refractive index photochromic ophthalmic article
US5708064A (en) * 1993-10-15 1998-01-13 Ppg Industries, Inc. High refractive index photochromic ophthalmic article
WO2000014325A1 (en) * 1998-09-03 2000-03-16 Ryser Christophe U Tinting plastic articles
US6464733B2 (en) * 1998-09-03 2002-10-15 Christophe U. Ryser Tinting plastic articles
AU762568B2 (en) * 1998-09-03 2003-06-26 Christophe U. Ryser Tinting plastic articles
EP2105766A3 (en) * 2008-03-26 2014-02-19 Hoya Lens Manufacturing Philippines Inc. Dyeing method for plastic lens

Also Published As

Publication number Publication date
DE4328675A1 (en) 1994-03-17
GB9315620D0 (en) 1993-09-08
KR940006752A (en) 1994-04-25
MX9302645A (en) 1994-05-31
CN1093813A (en) 1994-10-19
IL105147A0 (en) 1993-07-08
FR2695732A1 (en) 1994-03-18
JPH06108384A (en) 1994-04-19
CA2095703A1 (en) 1994-03-12
BR9302073A (en) 1994-03-22

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