WO2017194095A1 - Moule et procédé de préparation de verres de lunettes - Google Patents

Moule et procédé de préparation de verres de lunettes Download PDF

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Publication number
WO2017194095A1
WO2017194095A1 PCT/EP2016/060410 EP2016060410W WO2017194095A1 WO 2017194095 A1 WO2017194095 A1 WO 2017194095A1 EP 2016060410 W EP2016060410 W EP 2016060410W WO 2017194095 A1 WO2017194095 A1 WO 2017194095A1
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WIPO (PCT)
Prior art keywords
bis
mould
hours
ppm
process according
Prior art date
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PCT/EP2016/060410
Other languages
English (en)
Inventor
Fang Chen
Mark Wallace
Original Assignee
Carl Zeiss Vision International Gmbh
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 Carl Zeiss Vision International Gmbh filed Critical Carl Zeiss Vision International Gmbh
Priority to CN201680085554.3A priority Critical patent/CN109070505B/zh
Priority to PCT/EP2016/060410 priority patent/WO2017194095A1/fr
Publication of WO2017194095A1 publication Critical patent/WO2017194095A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C69/00—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore
    • B29C69/001—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore a shaping technique combined with cutting, e.g. in parts or slices combined with rearranging and joining the cut parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00932—Combined cutting and grinding thereof
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G02B1/041—Lenses

Definitions

  • the invention relates to spectacle lenses or spectacle lens blanks and more specifically to a process for preparing spectacle lenses or spectacle lens blanks comprising curing a monomer composition in an elongated mould to form a plastic rod, transversely cutting portions of plastic from the plastic rod and finishing the transversely cut portions to form spectacle lenses or spectacle lens blanks.
  • the plastic comprises a urethane resin.
  • the casting method commonly used in production of spectacle lenses generally comprises placing a monomer composition between two glass or metal mould surfaces held apart by a flexible gasket. The monomer is cured by
  • the casting process requires a large number of components and a large number of thicknesses and powers must be prepared and stocked to satisfy the range of customer demands. An error in the pairing of mould sections or gasket often results in rejection of the lens.
  • the lenses need to be cast in thicknesses greater than the finished spectacle requires to grinding and fitting to the wide range of customer requirements. This leads to significant wastage.
  • the process will comprise the steps of transversely cutting portions of plastic from the plastic rod, for forming the spectacle lenses or the spectacle lens blanks; and optionally refining the transversely cut portions to form the spectacle lenses or the spectacle lens blanks.
  • the plastic rod is of a urethane resin, which may be obtained, for example, from reactive monomer composition comprising an isocyanate, isothiocyanate or mixture thereof and active hydrogen compound such as a compound comprising a plurality of active hydrogen groups selected from the group consisting of hydroxy! (-OH), mercapto (-SH) and combinations thereof.
  • the urethane resin is a polythiourethane obtained, for example from a reactive monomer composition comprising an isocyanate and an active hydrogen compound comprising thiol groups, preferable a tri- and/or tetra-thiol compound.
  • the curing of the reactive monomer composition is polymerised under conditions of temperature and catalyst content to provide a reaction time to gel point sufficiently long to avoid striation.
  • the time to reach the gel point of the reactive monomer composition is preferably at least 50 hours, preferably at least 60 hours, more preferably at least 70 hours, still more preferably at least 80 hours, even more preferably at least 90 hours and most preferably at least 100 hours following initiation of polymerisation.
  • the monomer composition contains no more than 100 ppm such as from 0 to 100 ppm (preferably 1 to 100 ppm and more preferably 5 to 80 ppm) of a dialkyltin dihalide catalyst based on the weight of the monomer
  • a relatively small amount of catalyst, when used, is preferred in order to control the rate of reaction of the monomer composition and avoid defects.
  • the inside of the elongated mould is contacted with a release agent for the plastic rod, such as a fatty-alky! trichlorosilane.
  • strain or striation is an obstacle to the production of lenses having no defect or aberrations. Once striations form they are almost impossible to eliminate.
  • strain and striation refer to an optical distortion in the polymer in some parts having different refractive index, which can be observed by visual riblike aberrations.
  • transverse and transversely refer to sections generally across the rod which may be perpendicular to the longitudinal axis or at an angle from the perpendicular of, for example up to 30° such as up to 20° from perpendicular to the axis of the rod.
  • the portions may be cut from the rod with planar or curved faces. Cutting of portions with one or both curved faces may be used to reduce resin wastage and the amount of subsequent processing required to form lenses or lens blanks. Cut portions from the rod are subject to refining to form the spectacle lenses or the spectacle lens blanks.
  • many cut portions can be obtained from each rod and transformed into spectacle lenses or spectacle lens blanks such as, for example, at least 5 portions such as at least 10 or at least 20 portions cut and refined into spectacle lenses or spectacle lens blanks.
  • the portions may be cut using readily available equipment such as saws or other cutting instruments.
  • the portions may be cut and finished at the same time or rods may be held as stock to allow cutting of portions and refining as required according to customer demand.
  • the thickness of the lens forming portions cut from the rod may depend on the required spectacle lens type and/or optical prescription to be met by the spectacle lens. Typically the thickness of the cut portion will be in the range of from 1 mm to 30 mm such as from 5 mm to 20 mm or 5 mm to 15 mm.
  • cross-section refers to a section generally perpendicular to the longitudinal axis of the rod or mould.
  • gel point refers to the point at which a gel or insoluble polymer is formed. Gel point is the extent of conversion at which the liquid reactive monomer polymerisation mixture becomes a solid.
  • reactive monomer composition refers to a monomer composition, which may comprise individual reactive monomer molecules, or prepolymers, which can be cured and cross-linked or cross-linked to form a rigid spectacle lens.
  • Various embodiments can include lens forming mixtures with one or more additives such as: UV blockers, tints, photoinitiators or catalysts, and other additives one might desire in a spectacle lens.
  • urethane and urethane resin include resins of poiyurethanes and polythiourethanes which may be formed from a reactive monomer composition comprising at least one of isocyanate and isothiocyanate and monomer comprising a plurality of active hydrogen groups selected from hydroxyl (-OH), mercapto (-OH) and combinations thereof.
  • active hydrogen monomer will comprise from 2 to [0021]
  • the mould may have any of a wide range of cross-section shapes useful in preparing spectacle lenses such as round, oval, elliptic.
  • the cross section may have multiple edges such as square, rectangular, hexagonal and octagonal or the like although it will be appreciated that corners may be rounded to facilitate easy removal from the mould.
  • plastic rod refers to an elongated plastic material.
  • the aspect ratio of the rod (the length divided by maximum width of the cross-section) will be at least 2 and preferably at least 3.
  • Rods of significant length may be prepared in accordance with the invention having an aspect ratio of up to 50 such as up to 20 or up to 10.
  • the rod may have any of a wide range of shapes useful in preparing spectacle lenses such as round, oval, ellipse.
  • the cross section may have multiple edges such as square, rectangular, hexagonal, octagonal or the like although it will be appreciated that corners may be rounded to facilitate easy removal from the case.
  • the diameter of the cross section is generally at least 40 mm such as at least 60 mm or at least 70 mm.
  • the diameter is typically no more than 150 mm such as no more than 100 mm.
  • the maximum width will be at least 40 mm and the minimum is generally at least 30 mm In general the minimum width at a cross-section of the rod will be at least 30 mm and preferably at least 40 mm.
  • the rod at maximum width of the rod cross section is preferably at least 40 mm, more preferably at least 50 mm such as at least 60 mm.
  • the maximum cross-section is typically no more than 150 mm such as no more than 100 mm.
  • the aspect ratio of the rod is at least 3 and when the rod cross-section is round the diameter is at least 40 mm and wherein the rod has an irregular cross-section the minimum width (i.e. width about the centre of the cross section) is at least 30 mm and the maximum width is at least 40 mm.
  • the aspect ratio of the rod is at least 3 and when the rod cross- section is round the diameter is at least 50 mm and wherein the rod has an irregular cross-section the minimum width is at least 40 mm and the maximum width is at least 50 mm.
  • the aspect ratio of the rod is at least 3 and when the rod cross-section is round the diameter is at least 60 mm and wherein when the rod has an irregular cross section the minimum width is at least 50 mm and the maximum width is at least 60 mm.
  • the width referred to is the width about the centre of the cross section.
  • the processes may, for example, involve one or more processes such as grinding, polishing, application of coatings known in the industry such as hard-coatings, a nti reflective coatings, reflective coatings, UV coatings and photochromic coatings.
  • the process of the invention allows spectacle lenses to be manufactured in large quantities without the use of the glass mould sections and intermediate spacer gasket, which has been the standard method, used for many decades in formation of plastic spectacle lenses.
  • the process involves curing a reactive monomer composition in an elongated mould to form a plastic rod.
  • the elongated mould will preferable be oriented with the long axis upward to allow convenient loading of the monomer composition.
  • the mould may comprise a sidewall extending upward from a closed base, which may be sealed against the lower end of the sidewall.
  • the base can be removably sealed against the lower end of the sidewall to facilitate removal of the plastic rod following curing and optionally coating of the mould prior to casting to facilitate release of the plastic rod from the mould.
  • the reactive monomer composition may be selected from a range of reactive monomer compositions known to be useful in preparing spectacle lenses. Generally speaking reactive monomer compositions, which polymerise by step growth polymerisation are preferred. Urethane resins including polyurethanes and
  • polythiourethanes are preferred.
  • the preferred reactive monomer composition provides a urethane plastic rod and comprises an isocyanate and/or isothiocyanate and active hydrogen compound.
  • Effective control of the rate of polymerisation is important because in the relatively large volumes of resin required for rod formation compared with individual lens casting strain can rapidly develop. Control of the rate of polymerisation of urethane resins can be affected through one or more strategies such as temperature control, catalyst choice and amount and monomer selection. In contrast acrylate lenses, although able to be formed without striation in relatively thin section or small volumes provide higher levels of striation and are, generally speaking, less suited to formation of spectacle lenses using the rod casting process.
  • the polyurethane reactive monomer composition may comprise active hydrogen containing compounds selected from the wide range of polyols and polythiols known in the art.
  • the proportion of sulphur present may be selected according to the refractive index required.
  • the bifunctional or higher- functional polyol compounds include polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, butanetriol, 1 ,2-methyl glucoside, pentaerythritol, dipentaerythrito!, tripentaerythritol, sorbitol, erythritol, ribitol, arabinitol, xylitol, allitol, manitol, dulcitol, iditol, glycol, inositol, hexa
  • cyclobutanediol cyclopentanediol, cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo[5.2.1.02.6]decanedimethanol, bicyclo[4.3.0]nonanediol, dicyclohexanediol, tricyclo[5.3.1.1 Jdodecanediol, bicyclo[4.3.0]nonanedimethanol,
  • cyclohexanetriol multitol, lactitol, dihydroxynaphthalene, trihydroxynaphthalene, tetrahydroxynaphthalene, dihydroxybenzene, benzenetriol, biphenyltetraol, pyrogailol, (hydroxynaphthyl)pyrogallol, trihydroxyphenanthrene, bisphenol A, bisphenol F, xylylene glycol, di(2-hydroxyethoxy)benzene, bisphenol A bis(2-hydroxyethyl) ether, tetrabromobisphenol A, tetrabromobisphenol A bis(2-hydroxyethyl) ether,
  • dibromoneopentyl glycol and epoxy resin condensation reaction products of the above-mentioned polyols and organic polybasic acids such as oxalic acid, glutamic acid, adipic acid, acetic acid, propionic acid, cyclohexanecarboxylic acid, .beta.- oxocyclohexanepropionic acid, dimeric acid, phthalic acid, isophthalic acid, salicylic acid, 3-bromopropionic acid, 2-bromoglycolic acid, dicarboxycyclohexane, pyromeilitic acid, butanetetracarboxylic acid and phthalic acid; addition reaction products of the above-mentioned polyols and alkylene oxides such as ethylene oxide and propylene oxide; and addition reaction products of alkylene polyamines and alkylene oxides such as ethylene oxide and propylene oxide.
  • condensation reaction products of the above-mentioned polyols and organic polybasic acids
  • Examples of the Afunctional or higher-functional polyols having a sulfur atom include bis[4-(2-hydroxyethoxy)phenyl]sulfide, bis[4-(2-hydroxypropoxy)phenyl] sulfide, bis[4-(2,3-dihydroxypropoxy)phenyl] sulfide, bis(4-hydroxycyclohexyl) sulfide, bis[2-methyl-4-(hydroxyethoxy)-6-butylphenyl] sulfide, compounds obtained by adding ethylene oxide and/or propylene oxide to the above-mentioned compounds usually in a ratio of three molecules of the former oxide to one hydroxy I group of each latter compound, di-(2-hydroxyethyl) sulfide, 1 ,2-bis(2-hydroxyethylmercapto)ethane, bis(2- hydroxyethyl) disulfide, 1 ,4-dithian-2,5-diol, bis(2,3-dihydroxy
  • polythiol compound examples include: aliphatic polythiol compounds, such as methanedithiol, 1 ,2-ethanedithiol, 1 ,1-propanedithiol, 1 ,2- propanedithiol, 1 ,3-propanedithiol, 2,2-propanedithiol, 1 ,6-hexanedithiol, 1 ,2,3- propanetrithiol, 1 ,1-cyclohexanedithiol, 1 ,2-cyclohexanedithiol, 2,2-dimethylpropane- 1 , 3-d (thiol, 3,4-dimethoxybutane-1 ,2-dithiol, 2-methylcyclohexane-2,3-dithiol, 1 ,1- bis(mercaptomethyl)cyclohexane, bis(2-mercaptoethyl) thiomalate, 2,3-dimercapto-1-
  • the reactive monomer composition may comprise two or more compounds from one or more of the above sets of active hydrogen compounds.
  • Particularly preferred polythiol compounds are selected from the group consisting of 1 ,2-bis(2'-mercaptoethylthio)-3mercaptopropane [GST], pentaerythritol- tetrakis(3-mercaptopropionate) [PT P], pentaerythritol tetrakis(mercaptoacetate) [PTMA], trimethylolpropane-tris(3-mercaptopropionate) [TTMP], 2,5-bis(9- mercaptomethyl) ,4-dithiane [DMMD], pentaerythritol tetrakis(thioglycolate) [PETG],
  • the isocyanate component used in the process of preparing the preferred polyurethane plastic rod may be chosen from the wide range of diisocyanates known in the art for preparation of polyurethane lenses. These may include, for example, one or more selected from the group consisting of aromatic isocyanates, aliphatic isocyanates and alicyclic isocyanates.
  • Examples of the polyisocyanate compound having an aromatic ring include 1 ,4-phenylene diisocyanate, methyl-1 ,3-phenylene diisocyanate, 1 ,3- bis(isocyanatomethyl)benzene, mesitylene triisocyanate, 1 ,3-bis(2- isocyanatopropyl)benzene, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 1 ,5-diisocyanatonaphthatene and (3,3'-dimethyl-4,4'-biphenylylene) diisocyanate.
  • Examples of the aliphatic polyisocyanate compounds include hexamethylene diisocyanate, lysine ester triisocyanate and hexamethylene triisocyanate, and examples of the polyisocyanate compound having an alicyclic structure include isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanatomethyl)bicycloheptane, tris(isocyanatomethyl)cyclohexane and bis(isocyanatomethyl)-1 ,4-dithiane.
  • Examples of alicyclic isocyanate compound include bis-isocyanatomethyl- norbornanes (such as 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane and 2,6- bis(isocyanatomethyl)bicyclo-[2.2.1 Jheptane), 3,8-bis(isocyanatomethyl)tricyclo- [5.2.1.0 2 6 ]-decane, 3,9-bis(isocyanatomethyl)tricyclo-[5.2.1.0 2 6 ]-decane, 4,8- bis(isocyanatomethyl)tricyclo-[5.2.1.0 26 ]-decane and 4,9- bis(isocyanatomethyl)tricyclo-[5.2.1 , 02 6 ]-decane.
  • bis-isocyanatomethyl- norbornanes such as 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane and 2,6- bis(isocyanatomethyl)bicyclo-[2.
  • the more preferred isocyanates for use in preparing polyurethane plastic rods are xylenediisocyanate, di(isocyanatomethyl)norbornane and dicyclohexylmethane diisocyanate.
  • the ratio of isocyanate compounds to active hydrogen compounds may be selected using known chemistries.
  • the ratio of the compounds provides a molar ratio of NCO/(OH + SH) in the range of from 0.5 to 3.0, preferably 0.5 to 1.5.
  • the time for the reactive monomer composition to reach gel point from initiation of polymerisation is at least 50 hours, preferably at least 60 hours, more preferably at least 70 hours, still more preferably at least 90 hours and most preferably at least 100 hours.
  • the conditions under which polymerisation is conducted including the temperature and the formulation of the reactive monomer composition will have an influence on the reaction time to reach the gel point.
  • the reactive monomer composition may comprise a catalyst although in some embodiments it may be preferred to use no catalyst.
  • the catalyst type and amount of catalyst will influence the rate of reaction and may therefore be chosen together with reaction conditions to provide the desired gelation time to avoid strain.
  • Examples of catalysts which may be used in reactive monomer compositions for preparing polyurethane plastic rods include amines and diafkyltin dihalides such as di-(Ci to Ce alkyl)tin dichlorides including for example dimethyltin dichloride and dibutyltin dichloride.
  • Dibutyltin dichloride is the preferred catalyst when a catalyst is used.
  • Dialkyl tin dichloride catalysts is preferably present in amounts of no more than 100 ppm and more preferably no more than 80 ppm to provide control of the reaction rate.
  • the diafkyltin dichloride may be used in amounts of, for example, in the range of from 1 ppm to 100 ppm of the reactive monomer composition, preferably 1 ppm to 80 ppm of the reactive monomer compositions.
  • the catalyst may be present in an amount of at least 5 ppm (preferably at least 10 ppm) of the reactive monomer composition, that is, when present the catalyst is preferably in an amount in the range of from 5 ppm to 100 ppm, more preferably 10 ppm to 100 ppm and still more preferably where 80 ppm is the upper limit of the catalyst content.
  • composition comprises: a polythiol monomer, preferably selected from the polythiols referred to above and may more preferably be selected from the group consisting of 1 ,2-bis(2'- mercaptoethylthio)-3mercaptopropane [GST], pentaerythritol-tetrakis(3- mercaptopropionate) [PT P], pentaerythritol tetrakis(mercaptoacetate) [PTMA], trimethylolpropane-tris(3-mercaptopropionate) [TTMP], 2,5-bis(mercaptomethyl)1 ,4- dithiane [DM D] pentaerythritol tetrakis(thioglycolate) [PETG]; an isocyanate, preferably selected from the group consisting of
  • xylenediisocyanate, di(isocyanatomethyl)norbornane and dicyclohexylmethane diisocyanate wherein the molar ratio of NCO/(OH + SH) is in the range of from 0.5 to 3.0, preferably 0.5 to 1.5; and dialkyltin dichloride catalyst in an amount from 0 ppm to 100 ppm (preferably 1 ppm to 100 ppm such as 5 ppm to 100 ppm, more preferably 1 ppm to 80 ppm such as 5 ppm to 80 ppm) based on the reactive polymer
  • the molar ratio of NCO/SH is in the range from 0.5 to 3.0, more preferably 0.5 to 1.5.
  • the temperature at which the reaction proceeds will influence the time to reach gel point.
  • the temperature will be no more than 50°C, preferably no more than 40°C prior to reaching gel point.
  • the temperature will be in the range of from -20°C to 50°C, preferably 0°C to 45°C.
  • the temperature for providing the preferred time to gel point may be determined by routine experiment with the monomer composition and type and amount of catalyst (if any) used.
  • the reaction between polyols and isocyanates is more vigorous and exothermic than the corresponding reaction between polythiols and isocyanates. Accordingly, where the monomer composition comprises hydroxy I groups it may be preferred to control the rate of reaction by more careful temperature control.
  • the temperature may be controlled to no more than 20°C, such as no more than 15°C, or no more than 10°C.
  • Suitable reaction conditions may be determined by the skilled worker without undue experimentation having regard to the preferred time to gelation for obtaining acceptable levels or strain or no strain.
  • the temperature may, and preferably will be increased.
  • the temperature is increased to a temperature in the range of from 80°C to 160°C, preferably 120°C to 140°C.
  • the increase in temperature is preferably gradual, for example over a period of at least 5 hours and more preferably at least 10 hours.
  • the temperature in the range of 80°C to 160°C, preferably 120°C to 140°C is preferably maintained for a period of at least 30 minutes and more preferably at least 60 minutes.
  • the mould used in casting the plastic rod may be formed of a range of suitable materials having regard to the conditions and reagents used.
  • the mould may generally be formed of a metal such as stainless steel, a glass tube or a plastics material such as PVC.
  • a metal or glass it may be preferred to coat the inside of the mould is contacted with a non-stick agent to assist in the ease with which the plastic rod may be removed from the mould following curing.
  • the mould is a plastic mould and following casting the mould is transversely cut with the rod located therein. The section of mould cut with portions of rod may be more easily removed or may be used to protect the lenses following the cutting step of the process.
  • the non-stick agent should not deleteriously affect the quality of the lenses which are produced from the plastic rod. Some agents such as general lubricants may introduce unacceptable striation or cloudiness.
  • silanes and in particular alkyltrihalosilanes such as fatty- alkyltrichlorosilanes and fatty-alkyltrifluorosilanes may be used to modify the internal surfaces of the mould (particularly a metal or glass mould) to facilitate removal of the cast plastic rod from the mould.
  • the silane non-stick agents are particularly preferred as they bond to the inner surfaces of the mould and excess unbound non-stick agent can be removed by rinsing the mould with a volatile solvent such as acetone to provide rapid drying and preparation of the mould for the casting process.
  • the preferred fatty-alkyltrihalosilanes are Ci 2 to C 2 2 alkyl trichlorosilanes such as octadecyl trichlorosilane.
  • the mould releasing affect may be achieved by contacting the internal surface of the mould with the silane in a dilute solution (about 1 %) in a suitable solvent such as a petroleum distillate.
  • the internal surfaces may
  • the mould may optionally be coated or alternatively the mould and rod may together be transversely cut to provide the lens portions and the resulting mould segments removed from portions of the rod which are refined into lenses or lens blanks.
  • the above described pre-treatment of the mould may also be applied in moulds usable for conventional spectacle Jens casting methods.
  • the inner surface of a mould usable for spectacle lens casting may be surface treated with at least one non-stick agent to reduce mould adhesion and/or facilitate the mould opening.
  • Preferably silanes and more preferably alkyltrihalosilanes may be used as non-stick agent.
  • fatty- alkyltrichlorosilanes preferably C 12 to C 2 2 alkyl trichlorosilanes, further preferably Ci 6 to C20 alkyl trichlorosilanes, and fatty-alkyltrifluorosilanes as non-stick agents.
  • Figures 1(a), (b) and (c) show a mould for casting a cylindrical rod (i.e. or round cross section.
  • Figure 1(a) is a view from above with the mould oriented in the upright position;
  • Figure 1(b) shows a longitudinal section of the mould taken through the line A-A' of Figure 1(a) and
  • Figure 1 (c) is a perspective view showing the inside of the base portion of longitudinal section through the line A-A' of Figure 1(a).
  • Figure 2(a), (b) and (c) show a mould for casting a rod of oval cross-section.
  • Figure 2(a) is a view from above with the mould oriented in the upright position;
  • Figure 2(b) shows a longitudinal section of the mould taken through the line A-A' of Figure 2(a)
  • Figure 2(c) is a perspective view showing the inside of the base portion of longitudinal section through the line A-A' of Figure 2(a).
  • Figure 3(a), (b) and (c) show a mould for casting a rod of elliptical cross- section.
  • Figure 3(a) is a view from above with the mould oriented in the upright position;
  • Figure 3(b) shows a longitudinal section of the mould taken through the line A-A' of Figure 3(a) and
  • Figure 3(c) is a perspective view showing the inside of the base portion of longitudinal section through the line A-A' of Figure 3(a).
  • Figure 4 is a graph referred to in Example 4 showing the variation of gelling time (i.e. the time from commencement of polymerisation to reaching gel point) with concentration of dibutyltin dichloride thermal polymerisation catalyst for general composition of Example 1 maintained at 40°C.
  • Figure 5 is a graph referred to in Example 5 showing the variation of gelling time (i.e. the time from commencement of polymerisation to reaching gel point) with concentration of dibutyltin dichloride thermal polymerisation catalyst for the
  • Figure 6 is a graph referred to in Example 7 showing the variation of gelling time (i.e. the time from commencement of polymerisation to reaching gel point) with concentration of dibutyltin dichloride thermal polymerisation catalyst maintained at 40°C for the general composition of Example 3.
  • Figure 7 is a graph referred to in Example 8 showing the variation of gelling time (i.e. the time from commencement of polymerisation to reaching gel point) with concentration of dibutyltin dichloride thermal polymerisation catalyst for the
  • Figure 1 shows a mould (100(a)) formed of stainless steel and including a cylindrical side wall (1 10) extending upward from a closed base (120) to an open top end (130) for receiving reactive monomer composition.
  • the length of the mould may provide an aspect ratio of at least 3 such as at least 5.
  • the diameter of the mould (A- ⁇ ') may be at least 50 mm, at least 60 mm or at least 70 mm. Typically the diameter will be no more than 150 mm such as no more than 100 mm.
  • the base lower end (140) of the side wall includes an openable closure (150) comprising an annular recess (155) receiving a washer (156) engaging the side wall to resist the egress of reactive monomer composition.
  • the lower end of the side wall is seated on a portion (156) of the base which extends below the side wall (1 10).
  • Figures 2 and 3 show moulds (100(b) and 100(c)) formed of stainless steel and include a side wall (1 10) extending upward from a closed base (120) to an open top end (130) for receiving reactive monomer composition.
  • the maximum thickness of the cross section ( ⁇ - ⁇ ') is generally at least 50 mm such as at least 70 mm and will generally be no more than 150 mm such as no more than 100 mm.
  • the minimum thickness (orthogonal to the centre point of the section A-A') is generally at least 30 mm such as at least 40 mm and will generally be no more than 100 mm such as no more than 80 mm.
  • the lower end (140) of the side wall includes a openable closure (150) formed by a base mounting (160) extending about the bottom end (140) of the side wall (1 10) and a base plate (170) forming a closure for the bottom end (150) with a seal or washer (180) providing a seal against egress of the monomer reactive composition when the base (120) is closed.
  • the base mounting (160) and base plate (170) may be held together with a seal (180) there between by fasteners (190) urging the base mounting and base to seal with the washer there between.
  • the moulds (100(a), 100(b), 100(c)) are closed at the lower end of the side wall (1 10) and the internal surfaces (200) of the mould are contacted with a non-stick agent such as a fatty-alkylthchlorosilane as a dilute solution of in a solvent such as a petroleum distillate.
  • a non-stick agent such as a fatty-alkylthchlorosilane as a dilute solution of in a solvent such as a petroleum distillate.
  • the non-stick solution may be rinsed with a volatile solvent such as acetone and the internal surfaces allowed to dry.
  • the liquid reactive monomer composition is introduced to the mould (100 (a), (b) or (c)) at the top end (130) in an amount to achieve the required rod length
  • Rods of significant length may be prepared in accordance with the invention having an aspect ratio of up to 50 such as up to 20 by varying the length of the mould side wall (1 10) and amount of reactive monomer composition.
  • the top end of the mould may be closed with a temporary closure to exclude dust or other material entering the mould.
  • Mixing of the isocyanate and active hydrogen compound in the mould or prior to introduction of the mould is the initiation of polymerisation.
  • the monomer composition, temperature and catalyst may be chosen to provide a time to gel point of at least 50 hours, preferably at least 60 hours, more preferably at least 70 hours, still more preferably at least 80 hours and most preferably at least 100 hours following initiation of polymerisation.
  • the temperature is generally gradually increased to increasing to in the range of 80°C to 160°C, preferably 120°C to 140°C is preferably maintained for a period of at least 30 minutes and more preferably at least 60 minutes.
  • the mould and polymerised reactive monomer are then cooled and the plastic rod removed from the mould.
  • the rod may be subject to a post curing heating step at a temperature in the range of 80°C to 160°C, preferably 120°C to 140°C.
  • the rod is then cut transversely to provide portion for forming spectacle lenses or spectacle lens blanks which may be finished or semifinished using processes known in the art such as grinding, polishing and coating with any of a variety of coatings known in the art for colouring, providing photochromism, toughening against damage or providing optical effects.
  • the portions may be cut from the rod so as to provide planar or curved faces which may then be subject to the processes used to provide finished or semifinished lenses.
  • lens forming portions from the rod allows significant savings with regard to wastage of plastics material.
  • Lenses individually cast by traditional methods are generally much larger than the fitted size required by the wearer of the spectacles leading to significant wastage.
  • the process of the invention allows rods to be formed in a range of cross section shapes and dimensions minimising wastage. Lens portions can also be prepared to more closely match the wearers specifications.
  • This aspect of the invention also allows the transport and storage of rods rather than individual lens blanks which avoids the need to pack and protect the individual lenses so as to prevent damage to optical surfaces.
  • a stainless steel tube (round cross-section) with a cap and o-ring seal at the bottom was used having an internal diameter of 70mm and 270 mm length.
  • a reactive monomer composition (dibutyltin dichloride) was prepared having the composition shown in Table 1.
  • 9G is a carrier for the dyes, it is NK ester 9G - polyethylene glycol 400 dimethacrylate
  • the reactive monomer composition was firstly filtered with 4.5 micron filter then stirred and degassed for 1 hour at 100 Pascal vacuum.
  • the metal tube filled with reactive monomer composition was placed vertically in an oven.
  • the oven is programmed with curing cycle shown in Table 2.
  • the metal tube was treated with non-stick material, and the monomer shrunk during the polymerisation, after removing the metal cap and bouncing the metal tube against a rubber surface, the polymer rod can be pushed out from the metal tube.
  • a saw was used to cut a slice of plastic from the plastic rod. This slice of plastic was blocked on one side first and surfaced with freeform cutting and polishing machine on one side. Then the plastic was blocked on the polished side and cut and polished on another side with the freeform machine. The resulted lens was checked under polariscope and Bulbtronics light and shown to be uniform. There was an insignificant level of "strain" in the lens.
  • Example 2 the only difference from Example 1 is that the shape of the mould is different.
  • the moulds used in Example 2 included an oval cross-section mould shown in Figure 1a and an elliptical cross-section mould shown in Figure 1 b.
  • Oval shaped and elliptical cross-section rods can save a lot of monomers to reduce wastage in both materials and cutting time.
  • Example 3 The composition of Example 3 was prepared by mixing the components in the parts by weight shown in Table 4. The composition was cured in a mould prepared according to Example 1 Part (a) and the mould filled in accordance with Example 1 Part (c). The curing process was as referred to in Example 1 Part (d) except that the step 2 of the curing cycle was conducted over 7.6 days. The processing steps of Example 1 Part (e), (f) and (g) were repeated and the lens was found to be uniform. There was insignificant "strain" in the lenses.
  • a range of reactive monomer composition samples in accordance with the composition of Example 1 (Tablel) were prepared with various catalyst (DBC) concentrations as shown in Table 5. Each sample was a 20 grams sample and was placed in a 25 ml glass vial with lid on.
  • Example 7 The procedure of Example 5 was repeated using an oven temperature of 30°C rather than 40°C. The results are shown in Table 7.
  • Example 1 -Part (a) On the information from the results reported in Example 6 a tube casting stainless steel tube referred to in Example 1 -Part (a) was conducted as follows [0087] The DBC concentration was selected as 100 ppm. The curing cycle was selected to hold at 30°C for 160 hours before ramping up the temperature. The composition of a total of 1.9 Kg had the composition shown below in Table 9.
  • Stepl Hold the oven temperature at 30°C for 160 hours
  • Step 2 Heat up from 30°C to 130°C evenly and gradually within 40 hours
  • Step 3 Hold at 130°C for 2hours
  • Step 4 Cool down from 130°C to 20°C within 3 hour Table 11
  • Example 5 The testing of Example 5 was carried out using the composition of Example 3 at 40°C and 30°C. Table 12 summarized the result at 40°C.
  • the reactivity of the reactive monomer composition of Example 3 is higher than that of Example 1.
  • the monomer mix was gelled after 3 days.
  • the samples with 30ppm, 40ppm, 50ppm, 100ppm of DBC all gelled after 1 day at 40°C.
  • Example 1 The process of Example 1 was repeated with the exception that the metal tube was not treated with octadecyl trichlorosilane solution. After curing, it was very difficult to get the plastic rod from the metal tube due to the strong adhesion between the metal tube and the plastic rod.
  • Tinuvin 765 hindered amine light stabilizer
  • NK Oligo U-4HA urethane monomer having 4 terminal acrylic or methacrylic groups by Shin Nakamura Chemical
  • BP2EMA bisphenol A ethoxylated di methacrylate
  • the dimension of the PVC pipe is 70 mm in internal diameter, 75mm in external diameter.
  • the length of the pipe was 520 mm. There were lids on both ends of the PVC pipe.
  • the pipe was filed with nitrogen gas after filling of monomer mix.
  • the methacrylate monomer composition based on the above formulation was prepared and cast in a PVC tube using the curing cycle below. This composition corresponds to a commercial lens material.
  • a methacrylate reactive monomer system was prepared in an amount of 2 Kg in accordance with the composition shown in Table 16.
  • the dimension of the PVC pipe is 70 mm in internal diameter, 75mm in external diameter.
  • the length of the pipe was 52 cm. There were lids on both ends of the PVC pipe.
  • the pipe was filed with nitrogen gas after filling of monomer mix.
  • Step 1 20 51 Hold at 51°C for 20 hours
  • Step 2 64 90 Heat up from 51 to 90°C within 44 hours
  • Step 3 69 90 Hold at 90°C for 5 hours
  • Step 4 69.5 30 Cool down from 90 to 30°C within 0.5 hour Step 5 70 30 Hold at 30°C for 0.5 hour
  • Table 18 illustrates the influence of factors including reactive monomer type, volume, mould dimensions, catalyst amount and temperature on the gelling time of the composition.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polyurethanes Or Polyureas (AREA)

Abstract

La présente invention concerne un procédé de préparation de verres de lunettes ou d'ébauches de verres consistant à : durcir une composition de monomère réactif dans un moule allongé (200) pour former une tige en plastique pour couper transversalement des parties de celle-ci pour former des verres de lunettes ou des ébauches de verres de lunettes.
PCT/EP2016/060410 2016-05-10 2016-05-10 Moule et procédé de préparation de verres de lunettes WO2017194095A1 (fr)

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CN201680085554.3A CN109070505B (zh) 2016-05-10 2016-05-10 眼镜片以及用于制备眼镜片的方法
PCT/EP2016/060410 WO2017194095A1 (fr) 2016-05-10 2016-05-10 Moule et procédé de préparation de verres de lunettes

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018213423A1 (de) * 2018-08-09 2020-02-13 Carl Zeiss Vision International Gmbh Verfahren zur Herstellung von Brillengläsern oder Brillenglasrohlingen und Radialwerkzeug zur Herstellung von Brillengläsern oder Brillenglasrohlingen

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US4045547A (en) * 1974-11-21 1977-08-30 Warner-Lambert Company Fabrication of soft contact lens and composition therefor
US4155962A (en) * 1977-05-25 1979-05-22 Neefe Optical Laboratory, Inc. Method of removing molded lenses from the mold
US5451617A (en) * 1991-09-12 1995-09-19 Bausch & Lomb Incorporated Wettable silicone hydrogel compositions and methods for their manufacture
US5849222A (en) * 1995-09-29 1998-12-15 Johnson & Johnson Vision Products, Inc. Method for reducing lens hole defects in production of contact lens blanks
WO2000037971A1 (fr) * 1998-12-21 2000-06-29 Bausch & Lomb Incorporated Articles pour verres de contact fabriques a partir de comonomeres perfluores
US20060001184A1 (en) * 2004-06-30 2006-01-05 Phelan John C Method for lathing silicone hydrogel lenses
EP1872929A2 (fr) * 2006-06-30 2008-01-02 Hoya Corporation Procédé pour la fabrication d'une lentille en plastique
US20080291392A1 (en) * 2007-04-12 2008-11-27 Sicari Joseph E System and method for marking an ophthalmic lens
EP2248647A1 (fr) * 2008-02-20 2010-11-10 Hoya Corporation Procédé de production de lentille intraoculaire
JP2013043415A (ja) * 2011-08-26 2013-03-04 Fujikura Ltd インプリントモールド、及びプリント配線板の製造方法
US20150021826A1 (en) * 2012-03-08 2015-01-22 Danmarks Tekniske Universitet Silane based coating of aluminium mold
US20150061168A1 (en) * 2005-04-13 2015-03-05 Benz Research And Development Corporation Polymers for intraocular lenses
EP3017938A1 (fr) * 2014-11-06 2016-05-11 Carl Zeiss Vision International GmbH Procédé de préparation de verres de lunettes

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045547A (en) * 1974-11-21 1977-08-30 Warner-Lambert Company Fabrication of soft contact lens and composition therefor
US4155962A (en) * 1977-05-25 1979-05-22 Neefe Optical Laboratory, Inc. Method of removing molded lenses from the mold
US5451617A (en) * 1991-09-12 1995-09-19 Bausch & Lomb Incorporated Wettable silicone hydrogel compositions and methods for their manufacture
US5849222A (en) * 1995-09-29 1998-12-15 Johnson & Johnson Vision Products, Inc. Method for reducing lens hole defects in production of contact lens blanks
WO2000037971A1 (fr) * 1998-12-21 2000-06-29 Bausch & Lomb Incorporated Articles pour verres de contact fabriques a partir de comonomeres perfluores
US20060001184A1 (en) * 2004-06-30 2006-01-05 Phelan John C Method for lathing silicone hydrogel lenses
US20150061168A1 (en) * 2005-04-13 2015-03-05 Benz Research And Development Corporation Polymers for intraocular lenses
EP1872929A2 (fr) * 2006-06-30 2008-01-02 Hoya Corporation Procédé pour la fabrication d'une lentille en plastique
US20080291392A1 (en) * 2007-04-12 2008-11-27 Sicari Joseph E System and method for marking an ophthalmic lens
EP2248647A1 (fr) * 2008-02-20 2010-11-10 Hoya Corporation Procédé de production de lentille intraoculaire
JP2013043415A (ja) * 2011-08-26 2013-03-04 Fujikura Ltd インプリントモールド、及びプリント配線板の製造方法
US20150021826A1 (en) * 2012-03-08 2015-01-22 Danmarks Tekniske Universitet Silane based coating of aluminium mold
EP3017938A1 (fr) * 2014-11-06 2016-05-11 Carl Zeiss Vision International GmbH Procédé de préparation de verres de lunettes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018213423A1 (de) * 2018-08-09 2020-02-13 Carl Zeiss Vision International Gmbh Verfahren zur Herstellung von Brillengläsern oder Brillenglasrohlingen und Radialwerkzeug zur Herstellung von Brillengläsern oder Brillenglasrohlingen
DE102018213423B4 (de) 2018-08-09 2023-12-14 Carl Zeiss Vision International Gmbh Verfahren und Vorrichtung zur Herstellung von Brillengläsern oder Brillenglasrohlingen sowie Radialwerkzeug zur Herstellung von Brillengläsern oder Brillenglasrohlingen

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