WO1993023773A1

WO1993023773A1 - Process for preparation of oxygen permeable polymer material

Info

Publication number: WO1993023773A1
Application number: PCT/JP1993/000635
Authority: WO
Inventors: Kenji Yasuda; Tetsuo Ito; Osamu Kurita
Original assignee: Ciba-Geigy Ag
Priority date: 1992-05-14
Filing date: 1993-05-14
Publication date: 1993-11-25
Also published as: AU4087993A; JPH05310837A

Abstract

An oxygen permeable polymer material having both excellent oxygen permeability and good processability is provided. A process for the preparation of an oxygen permeable polymer material, which comprises polymerizing a mixture of a siloxanyl monomer having a polymerizable unsaturated bond and/or an acrylate type monomer and a compatible volatile organic solvent while removing a substantial portion of the organic solvent.

Description

DESCRIPTION

Process for preparation of oxygen perme _^le polymer material

(Technical field)

This invention relates to a process for preparation of an oxygen permeable polymer material particularly useful as ophthalmic materials such as contact lenses and intraocular lenses .

(Background art)

Various plastic materials, for example, polymethyl meth- acrylate, have conventionally been used as ophthalmic mate¬ rials such as contact lenses and intraocular lenses. How¬ ever, conventional ophthalmic materials have problems that sxygen permeabilities are low and contaminants in tear and intraocular fluid are easily attached thereto so that, for example, when said materials are processed into contact lenses, such contact lenses cannot be worn continuously for a long time.

Thus, highly water-containing soft contact lenses compris¬ ing poly(N-vinyl-2-pyrrolidone) as a main component, which can be worn for a long time have been developed. However, such lenses have insufficient mechanical strength due to high water content thereof, and are required to be steril- ized each time they are used as contact lenses, whereby handlings are extremely complicated.

On the other hand, as an ophthalmic material which does not have such drawbacks, attention has recently been paid to a non-water-containing ophthalmic material comprising a copolymer of siloxanyl monoacrylate or siloxanyl mono- methacrylate and fluoroacr late or fluoromethacr late.

However, this material has a drawback that its properties change greatly depending on the copolymerization ratio of siloxanyl monoacrylate or siloxanyl monomethacrylate and fluoroacrylate or fluoromethacrylate. For example, when the copolymerization ratio of siloxanyl monoacrylate or siloxanyl monomethacrylate is made larger, oxygen perme¬ ability is improved, but there are problems that adsorption or attachment of contaminants are remarkable, and the material becomes too brittle and soft, whereby handlings are complicated in another sense. To the contrary, when the copolymerization ratio of fluoroacrylate or fluoro- methacrylate is made larger, contaminants are hardly adsorbed or attached, but there is a problem that oxygen permeability is lowered.

As a process for obtaining contact lenses having good oxy¬ gen permeability, a method in which a monomer component and a solvent having compatibility therewith are mixed, the mixture is poured into a mold and polymerized, and then the solvent is removed from the polymerized molded product has been proposed in JP-A-89-225913. In this process, all amount of the solvent is removed after completion of the polymerization. Thus, when the mixture is poured into a lens-shaped mold and polymerized, a predetermined lens shape cannot be maintained at the stage of removing the solvent, and when the mixture is polymerized so as to have a lump shape such as a rod shape and a block shape, it is difficult to maintain the shape in the beginning of the polymerization so that it is difficult to carry out mechan¬ ical processings such as cutting after the polymerization and also a step of removing the solvent is required after completion of the polymerization, whereby there are problems in operatability and economy. (Disclosure of the invention)

Thus, an object of this invention is to provide an improved process for preparation of an oxygen permeable polymer material having both excellent oxygen permeability and excellent mechanical processability.

In order to solve the problems described above, the present inventors have studied intensively relations between pro- cesses for preparations of ophthalmic polymer materials comprising siloxanyl monoacrylate and/or siloxanyl mono¬ methacrylate, and fluoroacrylate and/or fluoromethacrylate, and characteristics of said polymer materials, and conse¬ quently found that by removing a substantial portion of a volatile organic solvent having compatibility with a mono¬ mer component during polymerization of the monomer compo¬ nent in the presence of the volatile organic solvent, an oxygen permeable polymer material having both extremely excellent oxygen permeability and good processability can be obtained, to accomplish this invention.

That is, this invention comprises a process for preparation of an oxygen permeable polymer material, which comprises mixing a monomer component comprising one or more polymer- izable monomer (s) represented by formula (1) shown below and/or one or more polymerizable monomer(s) represented by formula (2) shown below and one or more crosslinkable monomer(s) with a volatile organic solvent having compati¬ bility, and then polymerizing the mixture while removing a substantial portion of the above volatile organic solvent from a polymerization system,

A-X- Z (1)

wherein A represents a polymerizable unsaturated group, X represents a divalent hydrocarbon group or a divalent oxahydrocarbon group which is unsubstituted or substituted by hydroxy group, preferably a Ci to Cio alkylene group or a C4 to Cio oxaalkylene group unsubstituted or substituted by hydroxy group,

R¹, R², R³, R⁴, R⁵ and R⁶ may be the same or different from each other and each represent an alkyl group, a fluoroalkyl group, a phenyl group, a vinyl group, a hydrogen atom, provided that R¹ and R², R³ and R⁴ or R⁵ and R⁶ cannot be hydrogen atoms at the same time,

Y¹ or a group of formula: -0Si-Y²

J^> where Y¹, Y² and Y³ may be the same or different from each other and are each an alkyl group, a fluoroalkyl group, a phenyl group, a vinyl group or a hydrogen atom, provided that the case where no less than two of Y¹, Y² and Y³ are hydrogen atoms is excluded,

Z represents an alkyl group, a fluoroalkyl group, a tri— alkylsilylalkylene group or a hydrogen atom, and k is an integer from 0-100, preferably 0-20,

R⁷

I . CH₂=C-CO-R (2)

II 0 wherein R⁷ represents an alkyl group, a fluoroalkyl group, a fluorine atom or a hydrogen atom, and

R⁸ represents a hydrogen atom or an alkyl group, preferably a Ci to C20 alkyl group; or a fluoroalkyl group; preferably a Ci to C20 fluoroalkyl group bonded through a divalent hydrocarbon group, preferably a C to C4 hydrocarbon group; or an aminoalkyl, hydroxyalkyl or epoxyalkyl group; prefer¬ ably a Ci to Cio aminoalkyl, a C to Cio hydroxyalkyl or a Ci to C o epoxyalkyl group; a C3 to CQ monocyclic or a Cβ to C16 bi- or tricyclic hydrocarbon group; an arylalkyl group; or an aryl group. (Best modes for practicing the invention)

In the following, this invention is described in detail, and the object, constitution and effect of this invention will be clarified thereby.

In the polymerizable monomer represented by formula (1) to be used in this invention, the p- ymerizable unsaturated group A includes, for example, a -nyl group represented by formula CH2=CH-, an acryloxy grc ~ or methacryloxy group represented by formula CH₂=C (R)C - (where R is a methyl group, a fluoromethyl group, a f- orine atom or a hydrogen atom) , an acrylamide group represented by formula CH₂=CH- CONH-, a styryl group represented by formula CH2=CHC6H₄-, an acrylonitrile group represented by formula CH2=C(CN)- and a 2-cyanoacryloxy group represented by formula CH₂=C(CN)COO-.

X in formula (1) includes a divalent hydrocarbon group or a divalent oxahydrocarbon group which is unsubstituted or substituted by hydroxy group, preferably a Ci to C o alkyl- ene group or a C₄ to Cio oxaalkylene group unsubstituted or substituted by hydroxy group, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group and an octylene group, and the divalent hydrocarbon group of R⁸ in formula (2) includes a Ci to C₄ alkylene group such as a methylene group, an ethylene group, a propylene group and a butylene group; a glycerol group and a propylglycerol group.

Further, in R¹ to R⁶, Y¹ to Y³ and Z in formula (1) and R⁷ and R⁸ in formula (2) , the alkyl group includes, for exam¬ ple, linear or branched alkyl groups, preferably Ci - C20 linear or branched alkyl, more preferably Ci - Cio linear or branched alkyl, further preferably Ci - C5 linear or branched alkyl, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n- pentyl group, an isopentyl group, a neo-pentyl, a hexyl group, a heptyl group, an oct l group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group and a dodecyl group, and the fluoroalkyl group includes, for ex¬ ample, linear or branched fluoroalkyl groups, preferably Ci - C20 linear or branched fluoroalkyl, more preferably Ci - Cio linear or branched fluoroalkyl, further preferably C₂ - C5 linear or branched fluoroalkyl, such as a trifluoro- methyl group, a trifluoroethyl group, a trifluoropropyl group, a pentafluorobutyl group, a heptafluoropentyl group and a nonafluorohexyl group. R¹ to R⁶ or Y¹ to Y³ in for- mula (1) and R⁷ and R⁸ in formula (2) may be the same or different from each other, respectively and when k in for¬ mula (1) is 2-100, plural -Si(R³) (R⁴)-0- groups may be the same or different from each other.

Specific examples of the polymerizable monomer represented by formula (1) include siloxanyl monomethacrylates or siloxanyl monoacrylates such as pentamethyldisiloxanyl- methyl methacr late, pentamethyldisiloxanylmethyl acrylate, pentamethyldisiloxanylpropy1 methacrylate, pentamethyldi- siloxanylpropyl acrylate, methylbis(trimethylsiloxy) silyl- propyl methacrylate, methylbis (trimethylsiloxy) silylpropyl acrylate, tris (trimethylsiloxy)silylpropyl methacrylate, tris (trimethylsiloxy) silylpropyl acrylate, methylbis (tri¬ methylsiloxy) silylpropylgl cerol methacrylate, methylbis- (trimethylsiloxy) silylpropylglycerol acrylate, tris (tri¬ methylsiloxy) silylpropylglycerol methacrylate, tris (tri¬ methylsiloxy) silylpropylglycerol acrylate, mono (methylbis— (trimethylsiloxy)siloxy)bis (trimethylsiloxy) silylpropyl¬ glycerol methacrylate, mono(methylbis (trimethylsiloxy) - siloxy)bis (trimethylsiloxy) silylpropylglycerol acrylate, trimethylsilylethyltetramethyldisiloxanylpropylglycerol methacrylate and trimethylsilylethyltetramethyldisiloxanyl- propylglycerol acrylate; and fluorosiloxanyl monomethacrylates or fluorosiloxanyl mono- acrylates such as (3,3,3-trifluoropropyldimethylsiloxy)bis- (trimethylsiloxy) silylmethyl methacrylate, (3,3,3-tri- fluoropropyldimethylsiloxy)bis (trimethylsiloxy) silylmethyl acrylate, (3,3,4,4,5,5, 5-heρtafluoropentyldimethylsiloxy) - (methylbis (trimethylsiloxy) siloxy)trimethylsiloxysilyl- propyl methacrylate and (3,3,4,4, 5, 5, 5-heptafluoropentyldi- methylsiloxy) (methylbis (trimethylsiloxy) siloxy)trimethyl- siloxysilylpropyl acrylate.

Next, specific examples of the polymerizable monomer repre¬ sented by formula (2) include fluoromethacrylates or fluoroacrylates such as 2,2,2-trifluoroethyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl-α- fluoroacrylate, 2,2, 2-trifluoroethyl-α-trifluoromethyl acrylate, 2,2,3, 3-tetrafluoropropyl methacrylate, 2,2,3,3- tetrafluoropropyl acrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2,2,2, 2*,2',2'-hexafluoroisopropyl methacrylate, 2 ,2,2,2', 2', 2'- hexafluoroisopropyl acrylate, 2,2,3,4, 4, 4-hexafluorobutyl methacrylate, 2,2, 3, 4, 4, 4-hexafluorobutyl acrylate, 2,2, 3,3, 4, 4, 5, 5-octafluoropentyl methacrylate, 2,2,3,3,4,4, 5, 5-octafluoropentyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7- dodecafluoroheptyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7- dodecafluoroheptyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8, 9, 9-hexadecafluorononyl methacrylate, 2,2,3,3,4,4,5,5,6,6, 7, 7, 8, 8, 9, 9-hexadecafluorononyl acrylate, 3,3,4,4,5,5,6,6, 7,7, 8, 8, 8-tridecafluorooctyl methacrylate, 3,3,4,4,5,5,

6, 6,7,7, 8,8, 8-tridecafluorooctyl acrylate, 2,2,3, 3-tetra- fluoro-1-methylpropyl methacrylate, 2, 2, 3, 3-tetrafluoro-1- methylpropyl acrylate, 2,2,3, 3-tetrafluoro-1, 1-dimethyl- propyl methacrylate, 2,2,3, 3-tetrafluoro-1, 1-dimethylpropyl acrylate, 2,2,3,3,4, 4,5,5-octafluoro-1, 1-dimethylpentyl methacrylate and 2, 2 ,3,3, 4, 4, 5, 5-octafluoro-1, 1-dimethyl- pentyl acrylate; alkyl methacrylates or alkyl acrylates such as methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, isopropyl methacrylate, isopropyl acrylate, n- butyl methacrylate, n-butyl acrylate, t-butyl methacrylate, t-butyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, benzyl methacrylate, benzyl acrylate, isobornyl methacrylate and isobornyl acrylate; α-alkylacrylic acids or α-fluoroalkylacrylic acids such as (α-ethyl)acrylic acid, (α-butyl) acrylic acid, (α-trifluoro- ethyl)acrylic acid, (α-trifluoropropyl) acrylic acid and (α- nonafluorohexyl)acrylic acid; alkyl(α-alkyl) acrylates such as methyl-(α-ethyl) acrylate, ethyl—(α-ethyl) acrylate, propyl-(α-ethyl) acrylate, butyl- (α-ethyl) acrylate, 2-hydroxyethyl- (α-ethyl) acrylate, 2- hydroxypropyl-(α-ethyl) acrylate, diethylaminoethyl-(α- ethyl) acrylate, glycidyl-(α-ethyl) acrylate, methyl-(α- butyl) acrylate, ethyl-(α-butyl) acrylate, propyl-(α-butyl) acrylate, butyl- (α-butyl) acrylate, 2-hydroxyethyl-(α- butyl) acrylate, 2-hydroxypropyl-(α-butyl) acrylate, di¬ ethylaminoethyl-(α-butyl) acrylate and glycidyl-(α-butyl) acrylate; alkyl(α-fluoroalkyl) acrylates such as methyl-(α-trifluoro- ethyl) acrylate, ethyl-(α-trifluoroethyl) acrylate, propyl- (α-trifluoroethyl) acrylate, butyl-(α-trifluoroethyl) acrylate, methyl-(α-trifluoropropyl) acrylate, ethyl-(α- trifluoropropyl) acrylate, propyl-(α-trifluoropropyl) acrylate, butyl-(α-trifluoropropyl) acrylate, methyl- (α- nonafluorohexyl) acrylate, ethyl-(α-nonafluorohexyl) acrylate, propyl—(α-nonafluorohexyl) acrylate and butyl-(α- nonafluorohexyl) acrylate; and fluoroalkyl(α-fluoroalkyl) acrylates such as 2,2,2-tri- fluoroethyl-(α-trifluoroethyl) acrylate, 2,2,3,3-tetra- fluoropropyl—(α-trifluoroethyl) acrylate, 2,2,3,3,3-penta- fluoropropyl-(α-trifluoroethyl) acrylate, 2, 2, 2,2' , 2' ,2'- hexafluoroisopropyl-(α-trifluoroethyl) acrylate, 2,2,3, 4, 4, 4-hexafluorobutyl-(α-trifluoroethyl) acrylate, 2,2,3,3, 4, 4, 5, 5-octafluoropentyl- (α-trifluoroethyl) acrylate, 2,2, 3,3, 4, 4, 5, 5, 6, 6, 7, 7-dodecafluoroheptyl-(α-trifluoroethyl) acrylate, 2,2,3,3,4, 4,5,5, 6, 6,7,7, 8,8, ^c- , 9-hexadecafluoro- nonyl- (α-trifluoroethyl) acrylate, 3,3,4,4,5,5,6,6,7,7,

8, 8, 8-tridecafluorooctyl- (α-trifluoroethyl) acrylate, 2,2, 3,3-tetrafluoro-1-methylpropyl- (α-trifluoroethyl) acrylate, 2,2,3,3-tetrafluoro-1, 1-dimethylpropyl-(α-trifluoroethyl) acrylate, 2,2,3,3,4,4,5, 5-octafluoro-1, 1-dimethylpentyl- (α- trifluoroethyl) acrylate, 2,2, 2-trifluoroethyl- (α-nona- fluorohexyl) acrylate, 2,2,3,3,3-pentafluoropropyl- (α-nona- fluorohexyl) acrylate, 2,2,2,2,2, 2-hexafluoroisopropyl- (α- nonafluorohexyl) acrylate, 2,2,3, 4, 4, 4-hexafluorobutyl- •: - nonafluorohexyl) acrylate, 2, 2,3, 3, 4, 4, 5, 5-octafluoro- pentyl- (α-nonafluorohexyl) acrylate, 2,2,3,3,4,4,5,5,6-5, 7, 7-dodecafluoroheptyl-(α-nonafluorohexyl) acrylate, 2.?. 3,3,4,4,5,5,6,6,7,7,8,8,9, 9-hexadecafluorononyl-(α-nona- fluorohexyl) acrylate, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8-trideca- luorooctyl- (α-nonafluorohexyl) acrylate, 2,2, 3, 3-tetra- fluoro-1-methylpropyl-(α-nonafluorohexyl) acrylate, 2,2, 3,3-tetrafluoro-l, 1-dimethylpropyl- (α-nonafluorohexyl) acrylate, 2,2,3,3,4,4,5, 5-octafluoro-1, 1-dimethylpentyl-(α- nonafluorohexyl) acrylate, 2,2,2-trifluoroethyl- (α-penta- decafluorononyl) acrylate and 2, 2, 3, 3, 3-pentafluoropropyl- (α-pentadecafluorononyl) acrylate.

Among the polymerizable monomers represented by formula (1) or (2) , preferred monomers are siloxanyl monomethacrylates or siloxanyl monoacrylates such as pentamethyldisiloxanyl- methyl methacrylate, pentamethyldisiloxanylmethyl acrylate, pentamethyldisiloxanylpropyl methacrylate, pentamethyl- disiloxanylpropyl acrylate, methylbis (trimethylsiloxy) - silylpropyl methacrylate, methylbis (trimethylsiloxy) silyl¬ propyl acrylate, tris (trimethylsiloxy) silylpropyl meth- acrylate and tris (trimethylsiloxy) silylpropyl acrylate; fluorosiloxanyl methacrylates or fluorosiloxanyl acrylates such as (3,3,3-trifluoropropyldimethylsiloxy)bis (trimethyl¬ siloxy) silylmethyl methacrylate, (3,3,3-trifluoropropyldi¬ methylsiloxy)bis (trimethylsiloxy) silylmethyl acrylate, (3,3,4,4,5,5,5-heptafluoropentyldimethylsiloxy) (methylbis- (trimethylsiloxy)siloxy)trimethylsiloxysilylpropyl meth¬ acrylate and (3,3,4,4,5,5, 5-heptafluoropentyldimethyl- siloxy) (methylbis (trimethylsiloxy) siloxy)trimethylsiloxy¬ silylpropyl acrylate; fluoromethacrylates or fluoroacrylates such as 2,2,2-tri- fluoroethyl methacrylate, 2,2,2-trifluoroethyl-α-fluαro- acrylate, 2,2,2-tri luoroethyl-α-trifluoromethyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,3-penta- fluoropropyl methacrylate, 2,2,2,2',2^r,2'-hexafluoroisopro- pyl methacrylate, 2,2,3,4, ,4-hexafluorobutyl methacrylate, 2,2,3,3,4,4,5, 5-octafluoropentyl methacrylate, 2,2,3,3,4,4, 5,5, 6, 6,7,7-dodecafluoroheptyl methacrylate, 3,3,4,4,5,5, 6, 6,7,7,8,8, 8-tridecafluorooctyl methacrylate, 2,2,3,3- tetrafluoro-1-methylprop l methacrylate, 2,2,3,3-tetra- fluoro—1, 1-dimethylpropyl methacrylate and 2,2,3,3,4,4,5,5- octafluoro-1,1-dimethylpentyl methacrylate; and alkyl methacrylates or alkyl acrylates such as methyl meth¬ acrylate, methyl acrylate, ethyl methacrylate, ethyl acryl¬ ate, isopropyl methacrylate, isopropyl acrylate, n-butyl methacrylate, n-butyl acrylate, t-butyl methacrylate, t- butyl acrylate, cyclohexyl methacrylate, cyclohexyl acryl¬ ate, benzyl methacrylate, benzyl acrylate, isobornyl meth¬ acrylate and isobornyl acrylate.

The crosslinkable monomer in this invention is a poly- functional compound having two or more polymerizable unsaturated groups which can be copolymerized with the polymerizable monomer represented by formula (1) or formula (2) . However, this crosslinkable monomer does not include a compound having a vinyl group bonded to an Si atom among the polymerizable monomers represented by formula (1) . Specific examples of the above crosslinkable monomer include polyfunctional methacrylates or polyfunctional acrylates each having or not having a fluorine atom, such as ethylene glycol dimethacrylate, ethylene glycol diacryl- ate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate, propylene glycol dimeth¬ acrylate, propylene glycol diacrylate, 1, 4-butanediol di- methacrylate, 1,4-butanediol diacrylate, neopentyl glycol dimethacryalte, neopentyl glycol diacrylate, trimethylol- propane trimethacrylate, trimethylolpropane triacrylate, bisphenol A dimethacrylate, bisphenol A diacrylate, bistri- fluoromethyl bisphenol A dimethacrylate and bistrifluoro- methyl bisphenol A diacrylate; and silicone type polyfunctional compounds represented by formulae shown below.

Siloxanyl dimethacrylates of

CH₃ CH₃ CH₃ CH₃

I I I I

CH₂=C-CO- (CH₂ ) ₃-Si-O-Si- (CH₂ ) ₃-0C-C=CH₂

II I I II

0 CH₃ CH₃ 0

CH₃ CH₃ CH₃ CH₃

CH₂=C-CO-CH₂CHCH₂0- (CH₂ ) ₃- (Si-O) ₅-Si- (CH₂ ) ₃-OCH₂CHCH₂-OC-C=CH₂ 0 OH CH₃ CH₃ OH 0

fluorosiloxanyl dimethacrylates of CF

CH₃ CH₃ (CH₂) ₂ CH₃ CH₃

I I I I I

CH₂=C-CO- (CH₂) ₃-Si- (Si-O) ₈"Si- (CH₂) ₃-OC-C=CH₂ II I I I ||

O CH₃ CH₃ CH₃ 0 _;

dimethacrylates having cyclic siloxane groups of

CH₂= H₂

and siloxanyl dimethacrylates having bisphenol A ether groups of

CH₃ CH₃ CH₃ CCHH₃₃ CH₃ CH₃

=C-C0- (CH₂) ₃- (Si-O) ₈ Si) ₈- (CH₂) ₃-OC-C=CH₂ II I

0 CH₃ CH₃ CH₃ CH₃ 0

Among the above crosslinkable monomers , preferred monomers are polyfunctional methacrylates such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, neo¬ pentyl glycol dimethacrylate, trimethylolpropane trimeth- acrylate and bisphenol A dimethacrylate; and siloxanyl dimethacrylates of

CH₃ CH₃ CH₃ CH₃

I I I I

CH₂=C-CO- (CH₂) ₃-Si-O-Si- (CH₂) ₃-0C-C=CH₂

II [ I II

0 CH₃ CH₃ 0

CH₃ CH₃ CH₃ CH₃

I I I I

CH₂=C-C0- (CH₂) ₃- (Si-O) ₅-Si- (CH₂) ₃-0C-C=CH₂

0 CH₃ CH₃ 0 _and ₃

The copolymerization ratio of the polymerizable monomer(s) represented by formula(e) (1) and/or (2) and the crosslink- able monomer in this invention is generally 99.5/0.5 to 5/95, preferably 99/1 to 10/90 in terms of weight ratio. However, when the polymerizable monomer represented by for¬ mula (1) is used and said monomer has a vinyl group bonded to an Si atom, this vinyl group can be also polymerized so that it is desired that the copolymerization ratio of the above crosslinkable monomer is controlled depending on the desired crosslinking degree of a polymer material to be obtained.

Further, in this invention, a polymerizable monomer other than the above-mentioned may be used in combination, if desired. In that case, for example, by using a hydrophilic monomer such as acrylic acid, methacrylic acid,* vinyl pyri- dine, N-vinyl-2-pyrrolidone and 2-hydroxyethyl methac- X. - ate, hydrophilicity can be imparted on the surface of a polymer material to be obtained.

The volatile organic solvent in this invention is an or¬ ganic solvent which does not substantially inhibit polymer- ization reaction nor participate the reaction and has com¬ patibility. Here, the compatibility means compatibility with both the monomer component and the resulting copoly¬ mer. As such an organic solvent, preferred are those hav¬ ing a boiling point of 150"C or lower.

Specific examples of the above volatile organic solvent include saturated hydrocarbons such as n-pentane, n-hexane, n-heptane_r 2-methylhexane_., 2,4-dimethylpentane, cyclopen- tane and methylcyclopentane; unsaturated hydrocarbons such as 1-hexene, 1-heptene, cyclohexene, benzene and toluene; halogenated hydrocarbons such as dichloromethane, chloro¬ form, carbon tetrachloride, fluorobenzene and hexafluo- robenzene; ethers such as diethyl ether, diisopropyl ether, ethyl vinyl ether and tetrahydrofuran; and acetates such as ethyl acetate, n-propyl acetate and n-butyl acetate.

The volatile organic solvents in this invention may be used singly or in combination of two or more kinds.

The amount of the volatile organic solvent to be used in this invention is generally 5—200 parts by weight, prefer¬ ably 5-100 parts by weight based on 100 parts by weight of all monomer component. If the amount of the volatile organic solvent to be used is less than 5 parts by weight, oxygen permeability of a polymer material obtained may not be improved sufficiently, while if it exceeds 200 parts by weight, a polymer material obtained by polymerization may be easily deformed by shrinkage to lower processability.

The polymerization in this invention is carried out gener- ally by radical polymerization, and there may be used meth¬ ods such as

® a method in which polymerization is carried out by using a thermal polymerization initiator such as benzoyl peroxide and azobisisobutyronitrile, for example, in an amount of 0.01—5 parts by weight based on 100 parts by weight of all monomer component and, if necessary, raising a polymerization temperature stepwise,

© a method in which polymerization is carried out by using a photopolymerization initiator such as benzoin, benzophenone and ichler's ketone, for example, in an amount of 0.01-5 parts by weight based on 100 parts by weight of all monomer component, irradiating UV rays and, if necessary, raising a polymerization temperature step- wise,

® a method in which polymerization is carried out by using a thermal polymerization initiator and a photopoly- erization initiator in combination under irradiation of UV rays and, if necessary, raising a polymerization tempera¬ ture stepwise, © a method in which polymerization is carried out under irradiation of, e.g. UV rays.

When polymerization is carried out in the presence of a thermal polymerization initiator by raising a polymeriza¬ tion temperature stepwise, two or more kinds of thermal polymerization initiators having different decomposition temperatures may be used in combination.

In this invention, it is preferred that polymerization is carried out by using a thermal polymerization initiator and a photopolymerization initiator in combination, irradiating UV rays under atmosphere of an inactive gas such as nitro¬ gen, and raising a polymerization temperature stepwise.

Polymerization is preferably carried out at a temperature ranging from 0 to 150 ° C and, in the initial polymerization stage, preferably at a temperature ranging from 0 to 30 'C. It is also preferred to raise the temperature gradually from the intermediate stage to the final stage of the poly¬ merization. Polymerization is preferably carried out at atmospheric pressure. Polymerization time depends on the rate-determining step. An inert gas, e.g. nitrogen gas may be passed through to remove volatile organic solvents, even after termination of polymerization. In total, 4 to 48 hours are usually preferred. When a volatile organic sol¬ vent is evaporated during polymerization in the stream of an inert gas, such as nitrogen, the velocity of gas flow is preferably 0.1 to 1 liter/min in the initial polymerization stage, and the gas flow may be gradually increased towards the final polymerization stage, e.g. to about 5 liter/min.

In this invention, the polymerization while removing a sub- stantial portion of the volatile organic solvent from a polymerization system means that at least 70 % by weight or more, preferably 80 % by weight or more of the solvent mixed with the monomer component before initiation of poly¬ merization is removed during polymerization. The solvent still remaining after the polymerization can be removed almost completely by a suitable method such as a method of volatilization under reduced pressure and a method of evap¬ oration by heating.

When a substantial portion of the volatile organic solvent is removed from a polymerization system, there may be used, for example, (a) a method in which the solvent is removed continuously during polymerization, (b) a method in which the solvent is removed stepwise during polymerization. In the case of (a) , the removing rate of the solvent may be constant, or the removing rate of the solvent may be increased or decreased gradually. In the case of (b) , the removing rate of the solvent may be the same at the respec¬ tive stages, it may be increased successively or decreased successively at the respective stages, or further the removing rate may be the highest or the lowest at the middle stage of polymerization among the respective stages. These methods of removing the volatile organic solvent may be selected and practiced suitably in consideration of a monomer composition, a desired size or distribution of holes of a polymer material to be obtained, and a kind and an amount of the solvent.

In this invention, a polymerization vessel or polymeriza- tion device which can remove the volatile organic solvent during polymerization should be used. Such a polymeriza— tion vessel or polymerization device includes, for example, those having gaps through which the above organic solvent can be volatilized during polymerization, or those which are tightly sealed, but can be opened at a suitable stage during polymerization.

A method of carrying out polymerization while removing a volatile organic solvent has conventionally been used as a method of controlling a polymerization temperature in gen- eral solution polymerization and precipitation polymeriza¬ tion, using an organic solvent. However, said method is a technique which has not yet been attempted in the prepara¬ tion of an oxygen permeable polymer material such as oph¬ thalmic materials, which require precision processing.

In this invention, as clarified in Examples and Comparative examples described below, by carrying out polymerization while removing a substantial portion of the volatile or¬ ganic solvent, it is possible to obtain a polymer material in which not only oxygen permeability is highly improved, but also machinability and polishability which are indis¬ pensable for processing precision molded products such as contact lenses and intraocular lenses. Further, removal of the volatile organic solvent is carried out mainly from a monomer stage to a prepolymer stage (i.e. a partial poly¬ merization stage) so that occurrence of distortion of a polymer material accompanied with removal of the solvent can be inhibited, and a step of removing the solvent after polymerization is not required or said step is simplified, whereby preparation steps of an oxygen permeable polymer material can be greatly rationalized.

The polymerization in this invention can be carried out by, for example, a process for the preparation of a copolymer with a lump shape in which a mixture of a monomer component and a volatile organic solvent is polymerized while remov- ing a substantial portion of the volatile organic solvent. In that case, the copolymer with a lump shape obtained is cut and polished into a predetermined shape such as contact lenses and intraocular lenses.

The polymer material obtained according to this invention exhibits machinability and polishability similar to those of conventional hard lenses comprising polymethyl meth¬ acrylate. Thus, the polymer material can be easily pro- cessed into a molded product with a predetermined shape

(e.g. contact lenses, intraocular lenses), and also it is rigid and has extremely excellent oxygen permeability.

Further, when the polymer material obtained according to this invention is used for contact lenses and intraocular lenses, in which fittings with tear and intraocular fluid are required, it is preferred that after processing into a predetermined shape, hydrophilicity is imparted to the sur¬ face by alkaline treatment, plasma treatment using, e.g. oxygen and nitrogen, plasma polymerization treatment using a hydrophilic group-containing compound, vapor deposition, sputtering or ion plating treatment using, e.g. an inor¬ ganic oxide, or the like.

(Examples)

In the following, specific embodiments and effects of this invention are described in more detail by referring to Examples and Comparative examples, but this invention is not limited only by these Examples.

In these Examples and Comparative examples, tests of oxygen permeability, visible light transmission and processabili- ties are conducted as described below.

Oxygen permeability: The polymer material is processed into contact lenses and measured at 35°C in a 0.9 % by weight physiological saline solution by using a scientific research type film oxygen permeation meter manufactured by Rika Seiki Kogyo.

Visible light transmission:

Discs comprising the polymer material (thickness: 0.2 mm, diameter: 15 mm) are measured at a wavelength of 500-600 nm by using a double beam spectrophotometer Model 200-20 manu¬ factured by Hitachi, Ltd.

Processabilities :

Machinability

0 - Cut surface has luster

Δ - Cut surface has luster, but is slightly opaque

X - Cut surface is rough and whitened Polishabilit.y

0 - Polished surface has good luster

Δ - Uneven polishing occurs

X - Polished surface is rough and whitened

Example 1

35 parts by weight of siloxanyl dimethacrylate of formula

CH₃ CH₃ CH₃ CH₃

I I I I

CH₂=C-CO-(CH₂) ₃-Si-O-Si-(CH₂) ₃-OC-C=CH₂

II I I II

0 CH₃ CH₃ 0

20 parts by weight of 2,2, 2-trifluoroethyl methacrylate, 30 parts by weight of methyl methacrylate, 50 parts by weight of n-hexane, and 0.1 part by weight of benzoin methyl ether and 0.1 part by weight of azobisisobutyronitrile as poly¬ merization initiators are mixed sufficiently at room tem- perature, and the mixture is poured into a polymerization vessel made of polyethylene (radius: 2 cm, height: 4 cm) of which the upper side is opened. This polymerization vessel is placed in another polymerization vessel (inner volume: 500 cm³) to which nitrogen can be introduced. While flow¬ ing nitrogen at a flow rate of 1 liter/min, UV rays are irradiated at room temperature for 16 hours, and then poly¬ merization is carried out at 40^*C for 8 hours, at 80^*C for 8 hours and 120'C for 12 hours. During this polymerization process, substantially all amount of n-hexane is volatil¬ ized by accompaniment with flow of nitrogen.

After completion of the polymerization, the copolymer obtained is cut and polished to be processed into contact lenses and discs, and the tests are conducted, respec¬ tively. The test results are shown in Table 1.

Example 2

40 parts by weight of tris (trimethylsiloxy) silylpropyl methacrylate, 5 parts by weight of 2,2,2,2' ,2 ^r,2'-hexafluo- roisopropyl methacrylate, 30 parts by weight of methyl methacrylate, 5 parts by weight of ethylene glycol dimeth¬ acrylate, 10 parts by weight of ethyl(α-nonafluorohexyl) acrylate, 5 parts by weight of methacrylic acid, 80 parts by weight of fluorobenzene, and 0.1 part by weight of benzoin methyl ether and 0.1 part by weight of azobisiso- butyronitrile as polymerization initiators are mixed suffi¬ ciently at room temperature, and then the mixture is poly- merized in the same manner as in Example 1. After comple¬ tion of the polymerization, the copolymer is cut and pol¬ ished to be processed into contact lenses and discs, and the tests are conducted. The test results are shown in Table 1. Comparative example 1 (without solvent)

35 parts by weight of siloxanyl dimethacrylate of formula:

CH₃ CH₃ CH₃ CH3

I I I I

CH₂=C-CO- (CH₂) ₃-Si-0-Si- (CH₂) ₃-0C-C=CH₂

II I I II

0 CH₃ CH₃ 0 20 parts by weight of 2,2,2-trifluoroethyl methacrylate, 30 parts by weight of methyl methacrylate, and 0.1 part by weight of benzoin methyl ether and 0.1 part by weight of azobisisobutyronitrile as polymerization initiators are mixed sufficiently at room temperature, and the mixture is polymerized in the same manner as in "Example 1. After com¬ pletion of the polymerization, the copolymer is cut and polished to be processed into contact lenses and discs, and the tests are conducted. The .e≤t results are shown in Table 1.

Comparative example 2

A reaction mixture having the same composition as that of Example 1 is poured into a glass tube and replacement with nitrogen is carried out. In the same manner as in Example 1 except for not removing n-hexane during polymerization, polymerization is carried out to obtain a copolymer block. Thereafter, the copolymer block is dried under vacuum at 120^*C for 48 hours to remove n-hexane. The copolymer block after removing n-hexane is deformed greatly and cannot maintain its columnar shape, whereby it is impossible to mount it on a lathe for cutting. Table 1

(*) unit: 10^-11 cc-cm/cm³*sec-mmHg

(Utilizability in industry)

The oxygen permeable polymer material obtained according to the method of this invention has extremely high oxygen permeability and also excellent machinability and polisha- bility. Further, in this invention, a substantial portion of a volatile organic solvent is removed during polymeriza¬ tion so that a step of removing a solvent after polymeriza¬ tion is not required or a step of removing a solvent can be simplified. Thus, the oxygen permeable polymer material obtained according to this invention is extremely useful as ophthalmic materials which require precision processing such as contact lenses and intraocular lenses, and accord¬ ing to this invention, such ophthalmic materials can be prepared extremely rationally.

Claims

1. A process for preparation of an oxygen permeable polymer material, which comprises mixing a monomer compo- nent comprising one or more polymerizable monomer (s) repre¬ sented by formula (1) shown below and/or one or more poly¬ merizable monomer (s) represented by formula (2) shown below and one or more crosslinkable monomer(s) with a volatile organic solvent having compatibility, and then polymerizing the mixture while removing a substantial portion of the volatile organic solvent from a polymerization system,

R¹ R³ R⁵

I I I

A-X-Si-0-(Si-0)_k-Si-Z (1)

I- I' i^« wherein A represents a polymerizable unsaturated group, X represents a divalent hydrocarbon group or a divalent oxahydrocarbon group which is unsubstituted or substituted by hydroxy,

R¹, R², R³, R⁴, R⁵ and R⁶ may be the same or different from each other and each represent an alkyl group, a fluoroalkyl group, a phenyl group, a vinyl group, a hydrogen atom, provided that R¹ and R², R³ and R⁴ or

R⁵ and R⁶ cannot be hydrogen atoms at the same time,

Y¹ or a group of formula: -0Si-Y²

J^> where Y¹, Y² and Y³ may be the same or different from each other and are each an alkyl group or a fluoro¬ alkyl group, a phenyl group, a vinyl group or a hydro¬ gen atom, provided that the case where no less than two of Y¹, Y² and Y³ are hydrogen atoms is excluded, Z represents an alkyl group, a fluoroalkyl group, a trialkylsilylalkylene group or a hydrogen atom, and k is an integer from 0-100,

R⁷

CH₂=C-CO-R^{8 (}2⁾

II 0 wherein R⁷ represents an alkyl group, a fluoroalkyl group, a fluorine atom or a hydrogen atom, and R⁸ represents a hydrogen atom, an alkyl group, a fluoroalkyl group, an aminoalkyl group, a hydroxyalkyl group, an epoxyalkyl group, a monocyclic hydrocarbon group, a bi- or tricyclic hydrocarbon group, an arylalkyl group, or an aryl group.

2. A process according to claim 1, wherein at least 70 % by weight or more of the solvent mixed with the monomer component before initiation of polymerization is removed during polymerization.

3. A process according to claim 1, wherein at least 80 % by weight or more of the solvent mixed with the monomer component before initiation of polymerization is removed during polymerization.

4. A process according to claim 1, wherein the solvent is removed continuously during polymerization.

5. A process according to claim 1, wherein the solvent is removed stepwise during polymerization.

6. A process according to claim 1, wherein the polymeriz¬ able unsaturated group of A is one selected from a vinyl group represented by formula CH₂=CH-; an acr loxy group or methacryloxy group represented by formula CH₂=C(R) COO- where R is a methyl group, a fluoromethyl group, a fluorine atom or a hydrogen atom; an acrylamide group represented by formula CH2=CHCONH-; a styryl group represented by formula CH₂=CHC₆H₄-; an acrylonitrile group represented by formula CH2=C (CN) - and a 2-cyanoacryloxy group represented by formula CH₂=C(CN) COO-.

7. A process according to claim 1, wherein X is a methyl¬ ene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a glycerol group or a propyl- glycerol group.

8. A process according to claim 1, wherein R¹, R², R³, R⁴, R⁵ or R⁶ each represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n- pentyl group, an isopentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a trifluoromethyl group, a trifluoroethyl group, a trifluoropropyl group, a pentafluorobutyl group, a heptafluoropentyl group, a nonafluorohexyl group, a phenyl group, a vinyl group or a hydrogen atom, and

Z represents a methyl group, an ethyl group, an n- propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n- pentyl group, an isopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tri- fluoromethyl group, a trifluoroethyl group, a trifluoro¬ propyl group, a pentafluorobutyl group, a heptafluoropentyl group, a nonafluorohexyl group, a trimethylsilylethyl group, a trimethylsilylmethyl group or a hydrogen atom.

9. A process according to claim 1, wherein the polymeriz¬ able monomer represented by formula (1) is at least one selected from the group consisting of pentamethyldisiloxan¬ ylmethyl methacrylate, pentamethyldisiloxanylmethyl acryl- ate, pentamethyldisiloxanylpropyl methacrylate, penta- methyldisiloxanylpropyl acrylate, methylbis (trimethyl¬ siloxy) silylpropyl methacrylate, methylbis (trimethyl¬ siloxy) silylpropyl acrylate, tris (trimethylsiloxy) silyl- propyl methacrylate, tris (trimethylsiloxy) silylpropyl acrylate, (3,3,3-trifluoropropyldimethylsiloxy)bis (tri¬ methylsiloxy) silylmethyl methacrylate, (3,3,3-trifluoro¬ propyldimethylsiloxy)bis(trimethylsiloxy) silylmethyl acrylate, (3,3, ,4,5,5,5-heptafluoropentyldimethylsiloxy) - (methylbis (trimethylsiloxy) siloxy)trimethylsiloxysilyl¬ propyl methacrylate and (3,3,4,4,5,5, 5-heptafluoropentyldi- methylsiloxy) (methylbis (trimethylsiloxy) siloxy)trimethyl¬ siloxysilylpropyl acrylate.

10. A process according to claim 1, wherein R⁷ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a trifluoromethyl group, a trifluoroethyl group, a trifluoropropyl group, a penta- fluorobutyl group, a heptafluoropentyl group, a nonafluoro¬ hexyl group, a fluorine atom or a hydrogen atom, and R⁸ represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n- butyl group, an isobutyl group, a sec-butyl group, a t- butyl group, an n-pentyl group, an isopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group; or a trifluoromethyl group, a trifluoroethyl group, a trifluoropropyl group, a pentafluorobutyl group, a heptafluoropentyl group or a nonafluorohexyl group each of which is bonded through a divalent hydrocarbon group with 1-4 carbon atoms; or a cyclohexyl group, a benzyl group or an isobornyl group.

11. A process according to claim 1, wherein the polymeriz¬ able monomer represented by formula (2) is at least one selected from the group consisting of 2,2,2-trifluoroethyl methacrylate, 2,2,2-trifluoroethyl-α-fluoroacrylate, 2,2,2- trifluoroethyl-α-trifluoromethyl acrylate, 2,2,3,3-tetra- fluoropropyl methacrylate, 2,2,3,3, 3-pentafluoropropyl methacrylate, 2,2,2,2 ' ,2 ' , 2 '-hexafluoroisopropyl methacryl¬ ate, 2,2,3,4,4, 4-hexafluorobutyl methacrylate, 2,2,3,3,4,4, 5,5-octafluoropentyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7- dodecafluoroheptyl methacrylate, 3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl methacrylate, 2,2,3, 3-tetrafluoro-1- methylpropyl methacrylate, 2,2,3, 3-tetrafluoro-1, 1-di- methylpropyl methacrylate, 2,2,3,3, 4, , 5, 5-octafluoro-l, 1- dimethylpentyl methacrylate, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, isopropyl methacrylate, isopropyl acrylate, n-butyl methacrylate, n- butyl acrylate, t-butyl methacrylate, t-butyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, benzyl methacrylate, benzyl acrylate, isobornyl methacrylate and isobornyl acrylate.

12. A process according to claim 1, wherein the crosslink¬ able monomer is at least one selected from the group con¬ sisting of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, neopentyl glycol dimeth¬ acrylate, trimethylolpropane trimethacrylate and bisphenol A dimethacrylate; and siloxanyl dimethacrylates of

CH₃ CH₃ CH₃ CH₃

I I I I

CH₂=C-CO-(CH₂) ₃-Si-O-Si- (CH₂) ₃-OC-C=CH₂

II I I II

0 CH₃ CH₃ 0

_and

13. A process according to claim 1, wherein copolymeriza¬ tion ratio of the polymerizable monomer(s) represented by formula(e) (1) and/or (2) and the crosslinkable monomer is 99.5/0.5 to 5/95 in terms of weight ratio.

14. A process according to claim 1, wherein copolymeriza¬ tion ratio of the polymerizable monomer(s) represented by formula(e) (1) and/or (2) and the crosslinkable monomer is 99/1 to 10/90 in terms of weight ratio.

15. A process according to claim 1, wherein the volatile organic solvent is a solvent having a boiling point of 150^*C or lower and selected from the group consisting of n- pentane, n-hexane, n-heptane, 2-methylhexane, 2,4-dimethyl- pentane, cyclopentane, methylcyclopentane, 1-hexene, 1- heptene, cyclohexene, benzene, toluene, dichloromethane, chloroform, carbon tetrachloride, fluorobenzene, hexafluo- robenzene, diethyl ether, diisopropyl ether, ethyl vinyl ether, tetrahydrofuran, ethyl acetate, n-propyl acetate and n-butyl acetate.

16. A process according to claim 1, wherein the volatile organic solvent is used in an amount of 5-200 parts by weight based on 100 parts by weight of all monomer component.

17. A highly oxygen permeable polymer obtained by the process as claimed in claim 1.

18. A contact lens obtainable by a process according to claim 1.

19. An intraocular lens obtainable by a process according to claim 1.

20. A preformed polymer having excellent processability properties obtainable by a process according to claim 1.