Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
  • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
  • C08F290/06—Polymers provided for in subclass C08G
  • C08F290/068—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/48—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
  • C08G77/50—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms by carbon linkages
  • C08G77/52—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms by carbon linkages containing aromatic rings

Definitions

• the present invention relates to the manufacture of plastic optical articles such as video discs and ophthalmic lenses.
• the most widely used plastic ophthalmic lens material is polymerised diethylene glycol bis (allyl carbonate). This polymer has proved a satisfactory material for the manufacture of ophthalmic lenses because of a combination of features, including excellent transmission, resistance to discolouration, high strength and high impact resistance. The material has a reasonable abrasion resistance and can be coated to improve that resistance. Lenses formed from polymers including divinyl benzene are generally brittle and have a high yellowness index.
• Japanese Patent Appln. 63-309509 to Showa Denko KK discloses the formation of a prepolymer of divinyl benzene and a polythiol compound which may be used in the formation of optical materials with high refractive indexes.
• Japanese Patent Appln. 90152702 to Mitsubishi Gas discloses a pentaerythritol triacrylate or methacrylate polymer with a minor amount, e.g. 10-
• This polymer may be used to form optical lenses of high refractive index.
• the present invention provides a telomer formed from an effective amount of an aromatic olefin monomer; and a partially substituted di- or polysiloxane compound.
• the aromatic olefin monomer may include two or more reactive double bonds per molecule.
• An aromatic diolefin is preferred.
• the aromatic olefin monomer may be selected from divinyl benzene or derivatives thereof. Divinyl benzene is preferred.
• Other aromatic olefins may be included as discussed below.
• the aromatic olefin monomer may be present in amounts of from approximately 40 to 90% by weight, preferably approximately 50 to 80% by weight, based on the total weight of the telomer.
• the partially substituted di- or polysiloxane compound may be of any suitable type.
• partially substituted as used herein, we mean a siloxane compound including at least two free silane groups.
• a partially substituted di- tri- or tetra siloxane compound may be used.
• a disiloxane is preferred.
• the polysiloxane compound may be a tetra substituted disiloxane compound or its higher oligomers.
• a tetra substituted disiloxane is preferred.
• the substituted siloxane may be selected from the following:
• R-j , R2, R3 and R4, which may be the same or different, are selected from H and alkyl groups of 1 to 10 carbon atoms.
• a tetramethyl disiloxane (TMDS) is preferred Me Me Me
• the siloxane compound may be present in amounts of from approximately 10 to 60% by weight, preferably approximately 20 to 50% by weight, based on the total weight of the telomer composition.
• the telomer composition according to the present invention may be utilised in the preparation of an optical article such as a contact lens.
• the optical article may be characterised by being thinner and/or lighter than known prior art articles whilst retaining good abrasion, impact and heat resistance.
• the optical article may exhibit a high refractive index, excellent colour, good flexibility, low shrinkage, high gas permeability, and very low density.
• the polymeric article may also exhibit a low Yellowness Index.
• high refractive index we mean a polymer having a refractive index of at least approximately 1.55, preferably approximately 1.55 to 1.57.
• low density we mean a density in the range of approximately 1.15 to 1.25 g cm -3 .
• very low density as used herein we mean a density in the range of 1.0 to 1.15 g em -3 .
• a process for the preparation of a telomer which includes providing an effective amount of an aromatic olefin monomer; a partially substituted di- or polysiloxane compound; and an hydrosilation catalyst; mixing the monomers at elevated temperature in the presence of the hydrosilation catalyst for a period sufficient to allow reaction therebetween.
• the aromatic olefin may be a divinyl benzene.
• the partially substituted siloxane compound may be tetramethyl disiloxane (TMDS).
• the hydrosilation catalyst may include a metal catalyst.
• the metal catalyst may be a platinum or rhodium catalyst.
• a platinum catalyst is preferred.
• the platinum catalyst may be selected from h ⁇ PtCle, Pt(COD)Cl2, Karstedt's catalyst and Lameroux catalyst. The platinum catalyst is preferred.
• the reaction mixture may be heated to a temperature of approximately 50°C to 90°C, preferably 65°C to 75°C.
• the reaction may continue for approximately 12 to 24 hours.
• the reaction mixture may include a stoichiometric excess of aromatic olefin.
• the telomer may include a mixture of isomers and oligomers.
• the telomer may be further purified to remove such oligomers.
• a cross- linkable prepolymer casting composition including a telomer formed from an effective amount of an aromatic olefin monomer; and a partially substituted di- or polysiloxane compound.
• the aromatic olefin monomer and siloxane compound may be as described above.
• the cross-linkable prepolymer casting composition may optionally further include a polymerisable comonomer.
• the polymerisable comonomer may be selected to improve the properties and/or processability of the prepolymer casting composition.
• the polymerisable comonomer may be selected from any suitable type, e.g. methacrylates, acrylates, vinyls, vinyl ethers, allyls, aromatic olefins, ethers, polythiols and mixtures thereof.
• the polymerisable comonomer may be present in amounts of from approximately 1 to 60% by weight based on the total weight of the casting composition.
• the polymerisable comonomer may preferably be selected from one or more of aromatic olefins, polyoxyalkylene glycol diacrylates or dimethacrylates, polymerisable bisphenol monomers capable of forming a homopolymer having a high refractive index of more than 1.55, urethane monomers having 2 to 6 terminal acrylic or methacrylic groups, fluorene diacrylates or dimethacrylates, and thiodiacrylate or dimethacrylate monomers.
• the aromatic olefins may be selected from styrene, divinyl benzene (DVB), and 3,9-divinyl-2,4,8,10- tetraoxaspiro[5.5]undecane (DTU).
• the aromatic olefins may be present in amounts of from approximately 1 to 60% by weight, preferably approximately 5 to
• the thiodiacrylate or dimethacrylates may be selected from bis(4-methacryloylthioethyl)sulfide (BMTES) and bis(4-methacryloylthiophenyl)sulfide (BMTS).
• BMTES bis(4-methacryloylthioethyl)sulfide
• BMTS bis(4-methacryloylthiophenyl)sulfide
• the thiodiacrylate or dimethacrylate may be present in amounts of from approximately 1 to 60% by weight, preferably approximately 5 to 40% by weight, based on the total weight of the casting composition.
• the fluorene diacrylate or dimethacrylate monomer may be selected from a bisphenol fluorene dihydroxy acrylate (BFHA) or a bisphenol fluorene dimethacrylate (BFMA) or mixtures thereof.
• BFHA bisphenol fluorene dihydroxy acrylate
• BFMA bisphenol fluorene dimethacrylate
• the fluorene diacrylate or dimethacrylate monomer may be present in amounts of from approximately 1 to 35% by weight, preferably approximately 5 to 20% by weight.
• the polyoxy alkylene glycol diacrylate or dimethacrylate compound according to the present invention when present, may include ethylene oxide or propylene oxide repeating units in its backbone.
• a polyethylene glycol dimethacrylate is preferred.
• Suitable materials are those sold under the trade names NKESTER 4G, 9G, 14G or 23G by Shin Nakamura.
• the polyoxy alkylene glycol diacrylate or dimethacrylate component may be present in amounts of from approximately 1 % by weight to 60% by weight, preferably approximately 5% to 40% by weight, based on the total weight of the casting composition.
• the high index bisphenol monomer component in the cross-linkable casting composition when present may be selected from: dimethacrylate and diacrylate esters of bisphenol A; dimethacrylate and diacrylate esters of 4,4'bishydroxy-ethoxy-bisphenol A and the like.
• a preferred high index bisphenol compound is a bisphenol A ethoxylated dimethacrylate.
• a bisphenol A ethoxylated dimethacrylate sold under the trade designation ATM20 by Anchomer or Diacryl 101 by AKZO have been found to be suitable.
• Halogenated high index bisphenol compounds which may be used include those sold under the trade designation and NK Ester 534M by Shin Nakamura.
• the high index bisphenol monomer may be present in amounts of from approximately 1 to 50% by weight, preferably 5 to 40% by weight based on the total weight of the casting composition.
• the polythiol when present, may be selected from Pentaerythritol Tetrakis (3-mercapto-propionate) [PTMP], Trimethylolpropane Tris (3-mercapto- propionate) [TTMP], 4-mercaptomethyl-3,6-dithia-1 ,8-octanedithiol [MDO], Pentaerythritol Tetrakis (3-mercaptoacetate) [PTMA], Trimethylolpropane Tris (3- mercaptoacetate) [TTMA], 4-t-butyl-1,2-benzenedithiol, 2-mercaptoethylsulfide, 4,4'-thiodibenzenethiol and benzenedithiol.
• PTMP Pentaerythritol Tetrakis
• TTMP Trimethylolpropane Tris (3-mercapto-propionate)
• TTMP Trimethylolpropane Tris (3- mercapto
• the polythiol may be present in amounts of from approximately 1 to 60% by weight, preferably 20 to 50% by weight.
• cross-linkable coating composition may further include at least one poly-functional unsaturated cross- linking monomer.
• the poly functional unsaturated cross-linking monomer according to the present invention may be a tri- or tetra- functional vinyl, an acrylic or methacrylic monomer.
• the cross-linking monomer may be a short chain monomer for example trimethylol propane trimethacrylate, pentaerythritol triacrylate or tetracrylate, or the like.
• a material sold under the trade name SR-454 which is an ethoxylated trimethylol propane triacrylate, has been found to be suitable.
• the poly functional unsaturated cross-linking monomer may be present in amounts of from approximately 1 to 30% by weight, preferably approximately 5 to 10% by weight based on the total weight of the casting composition.
• the cross-linkable casting composition according to the present invention may further include a cross-linking initiator.
• the cross-linking initiator may be a radical heat and/or ultraviolet (U.V.) cationic or radical initiator.
• a radical heat initiator is preferred.
• the compositions may be cured by a combination of UV radiation and/or heat. The combination of UV radiation and heat may reduce the possibility of incomplete curing for example due to the phenomenon known as "radical trapping".
• composition with the addition of approximately 0.1 % to 2.0% by weight of initiator may be exposed to UV radiation for between 0.5 and 10 seconds.
• Any commercially viable UV curing system may be used.
• the cross-linkable casting composition may be to heat curing.
• the length of heat cure may be between approximately 1 hour up to approximately 48 hours.
• Monomer filled moulds are placed in an oven. The oven is heated in accordance with a prescribed heating regime.
• curing time is between approximately 6 to 24 hours. Heating profiles depend upon the type of monomers to be cured and the initiators used to cure them.
• the amount of initiator may vary with the monomers selected. It has been possible to operate with a relatively low level of initiator of between approximately 0.05 and 2.0%, preferably 0.4% to 1.0% by weight. The following initiators have been found to be suitable. - AIBN (Azo radical heat initiator) Azodiisobutyronitrile
• TX-29 (Dialkyl Peroxide radical heat initiator) 1 , 1 -di-(-butyl peroxy-3,3,5-trimethyl cyclohexane)
• TBPEH Alkyl Perester radical heat initiator
• Initiator may be a single component or combination of initiator components.
• additives may be present which are conventionally used in casting compositions such as inhibitors, dyes, UV stabilisers and materials capable of modifying refractive index. Mould release agents can be added but they are in general not required with the compositions used in the method of the present invention.
• Such additives may include: UV Absorbers including
• Cyasorb UV 531 -2-hydroxy-4-n-octoxybenzo-phenone
• Cyasorb UV5411-2 (2-hydroxy-5-t-octylphenyl)-benzotriazole -
• UV 2098 - 2 hydroxy-4-(2-acryloyloxyethoxy) benzophenone
• Ciba Geigy 770 - bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate Antioxidants including
• Ciba Geigy Irganox 245 triethylene glycol-bis-3-(3-tertbutyl-4-hydroxy-5- methyl phenyl)propionate - Irganox 1010 -2,2-bis[[3-[3,4-bis(1 ,1-dimethylethyl)-4-hydroxyphenyl]-1- oxopropoxy]methyl]-1 ,3-propanediyl 3,5-bis(1 ,1 -dimethyl ethyl)-4-hydroxy benzene propanoate
• Anticolouring agents including - Triphenyl phosphine
• monomeric additives may be included to improve processing and/or material properties, these include: methacrylic acid, maleic anhydride, acrylic acid adhesion promoters/modifiers such as Sartomer 9008, Sartomer 9013, Sartomer 9015 etc. dye-enhancing, pH-adjusting monomers like Alcolac SIPOMER 2MIM a charge-reducing cationic monomer to render the material more antistatic, example Sipomer Q5-80 or Q9-75 hydrophobic comonomers: Shin Nakamura NPG, P9-G etc. to reduce the water adsorption of the material viscosity modifiers
• a polymeric article formed from a cross- linkable prepolymer casting composition as described above may be an optical article.
• the optical article may provide characteristics equal to or greater than those achievable with articles made from diethylene glycol bis(allyl carbonate) but with a considerably reduced cure time and substantially increased throughput.
• the optical article may be further characterised by having reduced weight and/or thickness relative to the prior art, low Yellowness Index, high gas permeability and very low density, whilst retaining good abrasion, heat and impact resistance.
• the overall refractive index may be in the high refractive index range of approximately 1.56 or higher, preferably 1.56 to 1.57.
• optical articles prepared by the method of this invention include camera lenses, ophthalmic lenses including contact lenses and video discs.
• the casting composition may be formed into a suitable article by mixing in a convenient vessel the components making up the material, and then adding the curing catalyst and/or photo-initiator. The mixed material is then degassed or filtered. As the curing time is substantially reduced the casting process may be undertaken on a continuous or semi-continuous basis.
• Divinylbenzene 960 which is a mixture of 96% divinylbenzene (both meta and para isomers) and 4% ethyl-vinyl benzene was used as a starting compound.
• the material as received was a clear pale yellow liquid.
• TX29 1.1 di-tert butyl peroxy 3,3,5 trimethyl cyclohexane
• CH 3 TBPO t-butyl peroxy octoate
• shrinkage is about 7.8% after polymerisation.
• the low density appears to be a useful feature.
• Example 2 was repeated under similar conditions with monomer mixes as designated in Table 2 below. The results achieved are also given in Table 2. Satisfactory lenses were achieved in Examples 3 to 5, 8 and 9 inclusive. Examples 6 and 7 are comparative examples only.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1994
  • 1994-05-30 EP EP94916838A patent/EP0705296A4/de not_active Withdrawn
  • 1994-05-30 WO PCT/AU1994/000285 patent/WO1995000577A1/en not_active Application Discontinuation
  • 1994-05-30 JP JP7502234A patent/JPH08511814A/ja active Pending

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