GB2163173A - Oxygen permeable hard contact lens of silicon copolymer - Google Patents

Abstract

An oxygen permeable hard contact lens having an improved oxygen permeability and an improved fragility as well as excellent hardness and rigidity, is made of a copolymer comprising an organosilane or organosiloxane having in one molecule at least one group of the general formula (I): <IMAGE> wherein R<1> is hydrogen atom or methyl group, k is 0 or 1, and l is 1 or 3, and having at most 16 silicon atoms, e.g.tris(trimethylsiloxy)silylpropyl methacrylate, and a fluoroalkyl acrylate or methacrylate of the general formula (II): <IMAGE> wherein R<1> is as defined above, m is 0, or 1, n is 0 or an integer of 1 to 3, and Rf is a straight or branched fluoroalkyl group having 2 to 21 fluorine atoms e.g. 2,2,2-trifluoroethyl methacrylate.

Description

SPECIFICATION Oxygen permeable hard contact lens The present invention relates to hard contact lenses having an excellent oxygen permeability.

Contact lenses put presently on the market are classified into two large groups, i.e. soft contact lenses made of a water-absorptive polymer such as p6ly(2 - hydroxyethyl methacrylate) or a soft hyd rophobic polymer such as silicone rubber, and hard contact lenses made of a hard polymer such as poly(methyl methacrylate). The hard contact lenses are generally inferior in wearing sensation to the soft contact lenses, but they have excellent visual power correcting effect and durability and also have the advantages peculiarto the hard contact lenses such as easiness in-handling, and accordingly they are widely used at present.

Hard contact lenses havethe fatal defect that it is difficult to supply oxygen required in metabolism of corneal tissue from the atmosphere to cornea through the lens materials, in other words, the oxygen permeability is bad. Consequently, wearing ofthe hard contact lenses for a long period of time causes metabolictrouble ofthe corneal tissue. In recentyears, however, the above problem has been dissolved to some extent bythe appearance of an oxygen permeable hard contact lens made of a copolymer of methyl methacrylate and a special methacrylate compound having siloxane bond (Si-O bond) in its molecule, and the hard contact lenses have rised in clinical estimation.

However, the proposed copolymer ofthe methacrylate compound having siloxane bond is inferior in hardness and rigidity to poly(methyl methacrylate) used as a material of usual hard contact lenses, and also is fragile. Lack of hardness and rigidity not only makes it easy to take scratches on the lens surface and makes it difficult to prepare contact lenses of a constant quality according to a predetermined lens contour, but also invites the fatal defect that a stable absolute visual power is not obtained due to difficulty in maintaining a constant lens contour upon wearing. On the other hand, the fragility results in lowering ofthe durability and rise in frequency of breaking as well as lowering ofthe mechanical processability.Accordingly, in order to obtain oxygen permeable hard contact lenses having an improved fragility as well as hardness and rigidity desired for hard contact lenses, the proportion of methyl methacrylate must be increased while decreasing the proportion ofthe siloxane bond-contain ing methacrylate compound to be used as a main component. But, this results in falling into the dilemma thatthe oxygen permeability of the obtained copolymer is decreased.

It is an object ofthe present invention to provide a hard contact lens having an improved oxygen permeability.

Afurtherobjectofthe invention isto provide an oxygen permeable hard contact lens having an improved fragility as well as excellent hardness and rigidity.

These and other objects of the present invention will become apparentfrom the description hereinafter.

It has now been found that the above-mentioned objects can be attained by employing as a contact lens material a copolymercomprising a siliconcontaining acrylate or methacrylate and a fluoroalkyl acrylate or methacrylate.

In accordance with the present invention,there is provided an oxygen permeable hard contact lens made of a copolymercomprising (a) an organosilane or organosiloxane compound having in one molecule at least one group of the general formula (i):

wherein R1 is hydrogen atom or methyl group, k isO or 1, and I is 1 or3. and having at most 16silicon atoms, and (b) a compound ofthe general formula (ill):

wherein R1 is as defined above, m isO or 1, n is0 or an integer of 1 to 3, and Rf is a straight or branched fluoroalkyl group having 2 to 21 fluorine atoms.

The organosilane and organosiloxane compounds (hereinaftergenerically referred to as "Si-(M)A") used as a component (a) in the present invention include a compound of the general formula (III):

wherein R1 is hydrogen atom or methyl group, k is O or 1,1 is 1 or3, os is20r3, andX1,Y, andZl arethe same or different and each is -CH3 orOSi(CH3)3, and a compound ofthe general formula (IV):

wherein R1, k and I are as defined above, R2, R3 and R4 are an alkyl group having 1 to 3 carbon atoms, O < a < 4, and and provided O < a+b+c+dv4.

Preferable compounds (IV) are a compound a?the geneialformula (V):

wherein R1, kand I are as defined above, and X2, Y2 3 and Z2 are the same or different and each is

integer of 2 to 4, and a compound ofthe general formula (VI)

wherein R', k and I are as defined above, andy is an integer of2 to 4.

In thefluoroalkyl acrylate and methacrylate (II) (hereinafter generically referred to as "F-(M)A") used as a component (b) in the present invention, preferable substituent groups Rf are a perfluoroalkyl group represented bythe general formula (VII): -CpF2p+1 (VII) wherein p is an integer of 1 to 10, and a fluoroalkyl group represented by the general formula (VIII): -CpF2pH (VIII) wherein p is as defined above.

The Si-(M)A having a group ofthe general formula (I) in which R1 is not hydrogen atom, but methyl group, namelythe Si-(M)A having methacryloyloxy group, is preferably employed, since the hardness is large and also the heat resistance is good. Also, the Si-(M)A having the group (I) in which kis 0 ratherthan 1 provides a lens material having a higher oxygen permeability and a larger hardness, but is inferior in thecopolymerizabilitywith a hydrophilic monomer to the Si-(M)A having the group (I) in which k is 1. With respectto "I" in the general formula (I), the Si-(M)A having the group (I) in which I is 3 ratherthan 1 is chemically stable.

The Si-(M)A is an organosilane or organosiloxane compound having at most 16 silicon atoms, and has a straight, branched orcyclic silyl or siloxanyl group.

The oxygen permeability is raised with increasing the number of silicon atoms, but simultaneously the product becomes soft and fragile. Therefore, the Si-(M)A having 4to 10 silicon atoms is more preferable. The Si-(M)A having a branched orcyclic silyl orsiloxanyl group is preferably used rather than the Si-(M)A having a straightsilyl orsiloxanyl group, because of providing a harderlensmaterial.Also,the Si3(M)A having a siloxanyl group ratherthan silyl group is preferred, because of providing a lens material having a higher oxygen permeability.

With respectto the F-(M)A ofthe general formula (lI),fluoroalkyl methacrylates are preferably employed, since the hardness is large and also the heat resistance is good as compared with fluoroalkyl acrylates. The F-(M)Aofthe general formula (II) in which m isO ratherthan 1 provides a lens material having a higher oxygen permeability and a larger hardness, but is inferior in the copolymerizabilitywith a hydrophilicrnonomertotheF-(M)A(II) in which mis 1. Also, though "n" in the general formula (II) has no significant influence upon the physical properties of the product, the F-(M)A in which n is O or 1 is preferable, sincethe shorter the (CnH2n) group, the harderthe product.The Regroup is a straight or branched fluoroalkyl group having 2 to 21 fluorine atoms. The oxygen permeability is raised with increasing the number ofthe fluorine atoms in the Rf group, but simultaneously the product becomes soft and fragile. Therefore, preferablythenumberofthe flourine atoms in the Rf group is from 2to 5. Also, the branched Rf group is preferred than the straight Rf group, since a harder product is obtained.

In both of the Si-(M)A and the F-(M)A, the methacrylate compounds are preferred than the acrylate compounds, since the products having a larger hardness and better light resistance and chemical resistance are obtained.

Examples ofthe Si-(M)A used in the present invention are, for instance, pentamethyldisiloxanyl- methyl methacrylate, pentamethyldisiloxanylmethyl acrylate, pentamethyldisiloxanylpropyl methacrylate, pentamethyldisiloxanylpropyl acrylate, methylbis (trimethylsiloxy) silylpropyl methacrylate, methylbis (trimethylsiloxy) silylpropyl acrylate, tris (trimethylsiloxy) silylpropyl methacrylate, tris (trimethylsiloxy) silylpropyl acrylate, mono [methylbis (trimethylsiloxy) siloxyj bis (trimethylsiloxy) silylpropyl methacrylate, mono [methylbis (trimethylsiloxy) siloxy] bis (trimethylsiloxy) silylpropyl acrylate, tris [methylbis (trimethylsiloxy) siloxy] silylpropyl methacrylate, tris [methylbis (trimethylsiloxy) siloxy] silylpropyl acrylate, methylbis (trimethylsiloxy) silylpropylglycerol methacrylate, methylbis (trimethylsiloxy) silylpropylglycerol acrylate, tris (trimethylsiloxy) silylpropylglycerol methacrylate, tris (trimethylsiloxy) silylpropylglycerol acrylate, mono [methylbis (trimethylsiloxy) siloxy] bis (trimethylsiloxy) silyl-- propylglycerol methacrylate, mono [methylbis (trimethylsiloxy) siloxy] bis (trimethylsiloxy) silylpropylglycerol acrylate, trimethylsilylethyltetramethyldisiloxanylpropylglycerol methacrylate, trimethylsilylethyltetramethyldisiloxanylpropy Iglycerol acrylate, trimethylsilylmethyl methacrylate, trimethylsilylmethyl acrylate, trimethylsilylpropyl methacrylate, trimethylsilylpropyl acrylate, methylbis (trimethylsiloxy) silylethyltetramethyldisiloxanyl- methyl methacrylate, methylbis (trimethylsiloxy) silylethyltetramethyldisiloxanylmethyl acrylate, tetramethyltriisopropylcyclotetrasiloxanylpropyl methacrylate, tetramethyltriisopropylcyclotetrasilox- anylpropyl acrylate, tetramethylisopropylcyclotetra- siloxybis (trimethylsiloxy) silylpropyl methacrylate, tetramethyltriisopropylcyclotetrasiloxybis (trimethylsiloxy) silylpropyl acrylate, and the like. The Si-(M)A monomers may be employed alone or in admixturethereof.

Examples ofthe F-(M)A used in the present invention are, for instance, 2,2,2 - trifluoroethyl methacrylate, 2,2,2 -trifluoroethyl 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 -trifluoro -1 - trifluoromethylethyl methacrylate, 2,2,2 -trifluoro-l trifluoromethylethyl acrylate, 2,2,3,3 - tetrafluoro - t - amyl methacrylate, 2,2,3,3 tetrafluoro - t - amyl acrylate, 2,2,3,4,4,4 - hexafluorobutyl methacrylate, 2,2,3,4,4,4 - hexafiuorobutyl acry late, 2,2,3,4,4,4- hexafluoro -t- hexyi methacrylate, 2,2,3,4,4,4 - hexafluoro - t - hexyl acrylate, 2,2,3,3,4,4,5,5 - octafluoropentyl methacrylate, 2,2,3,3,4,4,5,5 - octafluoropentyl acrylate, 2,3,4,5,5,5 - hexafluoro - 2,4- bis (trifluoromethyl) pentyl methacrylate, 2,3,4,5,5,5 - hexafluoro - 2,4 - bis (trifluoromethyl) pentyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7 - dodecafluoropentyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7 - dodecafluoropentyl acrylate, 2 - hydroxy - 4,4,5,5,6,7,7,7 -octafl uoro - 6 - trifluoromethylheptyl methacrylate, 2 - hydroxy4,4,5,5,6,7,7 - octofluoro 6 -trifluoromethylheptyl acrylate, 2 - hydroxy - 4,4,5,5,6,6,7,7,8,9,9,9 - dodecaf luoro - 8 -trifluoromethylnonyl methacrylate, 2 hydroxy - 4,4,5,5,6,6,7,7,8,9,9,9 - dodecafl uoro - 8 -trifluoromethylnonyl acrylate, 2 - hydroxy 4,4,5,5,6,6,7,7,8,8,9,9,1 0,11,11,11 -hexadecafluoro 10 trifluoromethylundecyl methacrylate, 2 - hydroxy -4,4,5,5,6,6,7,7,8,8,9,9,1 0,11,11,11 - hexadecafl uoro - 10 -trifluoromethylundecyl acrylate, and the like. The F-(M)A monomers may be employed alone or in admixture thereof.

Copolymers having particularly excellent oxygen permeability, hardness and rigidity can be obtained, when there is employed as Si-(M)Atris (trimethylsiloxy) silylpropyl methacrylate of the formula (IX):

pentamethyldisiloxanyl propyl methacrylate of the formula (X):

or methylbis (trimethylsiloxy) silylpropyl methacrylate ofthe formula (Xl):

and there is employed as F-(M)A 2,2,2 - trifluoroethyl methacrylate of the formula (Xll):

2,2,3,3 -tetrafluoropropyl methacrylate ofthe fomula (XIII):

2,2,3,3,3 - pentafluoropropyl methacrylate ofthe formula (XIV):

or 2,2,2 -trifluoro - 1 trifluoromethylethyl methacry- late of the formula (XV)::

The F-(M)Aused in the present invention can provide a lens material having a higher oxygen permeability by the copolymerization with the Si (M)A as compared with the use of other acrylic monomers such as alkyl acrylates and methacrylates which have a similar chemical structuresto the F-(M)A, whereby it is possible to impart a high oxygen permeability and desired hardness and rigidity to the produced copolymerwithout extremely increasing the amount ofthe Si-(M)Ato be used. Also, the heat resistance and the chemical resistance such as resistance to n-hexane (nonpolar solvent), ethyl alcohol (polarsolvent) and acetone (amphiprotic solvent) are improved by the use of the F-(M)A as compares with the use of alkyl methacrylates or acrylates.

The ratio ofthe Si-(M)A to the F-(M)Awhich are main components ofthe copolymer in the present invention is from about 15: 85to about 80: 20 by weight, preferably from about 30 : 70to about 70: 30 by weight. When the amount ofthe Si-(M)A used is morethan the above range, the produced copolymer is soft and fragile, thus resulting in lowering ofthe mechanical processability, and also the chemical resistance is lowered. When the amount of the Si-(M)A is less than the above range, a sufficient oxygen permeability is not imparted to the produced copolymer.

In addition to the essential monomer components, i.e. Si-(M)A and F-(M)A, various monomers may be employed as comonomers in orderto modify the properties ofthe copolymer according to various purposes.

Alkyl acrylates and methacrylates are effective particularly for increasing the strength ofthe copolymer, thereby raising the durability as a contact lens.

Representative examples ofthe alkyl methacrylates and acrylates are, for instance, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, isopropyl methacrylate, isopropyl acrylate, t-butyl methacrylate, t-butyl acrylate, isobutyl methacrylate, isobutyl acrylate, t-amyl methacrylate, t-amyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, lauryl methacrylate, lauryl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, and the like. The alkyl methacrylates and acrylates may be employed alone or in admixture thereof. The amount of the alkyl acrylate orthe alkyl methacrylate is selected from 0 to about 60 parts by weight, preferablyabout5to about 30 parts by weight, based on 100 parts by weight of the whole monomer mixture to be subjected to the copolymerization.

As monomers having the same effects as the alkyl acrylates and methacrylates, there may also be employed styryl compounds such as styrene, alkyl esters of itaconic acid or crotonic acid, glycidyl methacrylate, glycidyl acrylate, tetrahydrofurfu ryl methacrylate, tetrahydrofurfu ryl acrylate and benzyl methacrylate. The amount ofthese monomers is selected from the same range as that of the alkyl acrylate or methacrylate.

The use of a cross-linking monomer is effective for stabilizing the lens contour and dimension and for increasing the chemical resistance. Representative examples of the cross-linking monomer are, for instance, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, allyl acrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and the like. The cross-linking monomers may be employed alone or in admixturethereof. The amountofthe cross-linking monomerisselectedfrom 0 to about 20 parts by weight, preferably about 1 to about 10 parts by weight, based on 100 parts byweightofthewhole monomer mixture to be subjected to the copolymerization.

The use of a hydrophilic monomer is effective for imparting a hydrophilic propertyto the obtained copolymerandforgiving agoodwaterwettabilityto a hard contact lens. Representative examples of the hydrophilic monomer are, for instance, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, N-vinyl pyrrolidone, dimethylacrylamide, and the like. The hydrophilic monomers may be employed alone or in admixture thereof. The amount ofthe hydrophilic monomer is selected from Oto about30 parts by weight, preferablyabout5to about 15 parts by weight, based on 100 parts by weight of the whole monomer mixture to be subjected to the copolymerization.The use ofthe hydrophilic monomer in an amount largerthan the above range is not desirable, since the obtained copolymer becomes waterabsorptive and shows a flexibility due to plasticization by impregnated water, thereby losing the characteristics as hard contact lenses.

Itisalso possible to impartan effectivehydrophilic propertytothe lens su rface, for instance, by applying corona discharge or plasma dischargetothe obtained hard contact lens or by treating the lens with a strong acid such as hydrochloric acid or nitric acid, instead of or in addition to the use of hydrophilic monomer.

The polymerization of a monomer mixture can be readily carried out by any methods usually employed in the field ofthis art. For instance, the polymerization is carried out at a temperature ranging from room temperature to about 130 C. by employing free radical polymerization initiators as used in the polymerization of usual unsaturated hydrocarbon compounds. Examples ofthe radical polymerization initiator are, for instance, benzoyl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile, and the like. The polymerization initiators may be employed alone or in admixture thereof. The polymerization initiator is employed in an amount of 0.01 to 1 party byweight per 100 parts byweig ht of the whole monomer mixture.

The shaping ofthe copolymer into contact lenses can be made by usual methods. For instance, polymerization may be conducted in a mold corres ponging to a shape of a contact lens to give a copolymerhaving a itntact lens shape directly. The thus obtained contact lens maybefurthersubjected to a mechanical finishing, as occasion demands.

Also, the polymerization may be conducted in an appropriate mold orvessel to give a lens material in theform of button, plate or rod, and the lens material maybethensubjectedto a usual mechanical processing such as cutting or polishing to give a contact lens of a desired shape.

The oxygen permeable contact lens ofthe present invention has the foilowing excellent properties. That is to say, since the lens is made of a material having an improved fragility as well as hardness and rigidity desiredforhard contact lenses, the lens has an improved durability and also it is possible to maintain a constant lens contour, whereby a stable corrected visual power can be obtained. Also, since the hard contact lens of the present invention has a higher oxygen permeability than a conventional oxygen permeable hard contact lens, it is possible to sufficiently maintain the metabolism of the corneal tissue even if the lenses are worn for a long period of time.

The present invention is more specifically described and explained by means ofthe following Examples in which all parts are by weight unless otherwise noted. It is to be understood thatthe present invention is not limited to the Examples, and various changes and modifications may be made in the invention without departing from the spirit and scope thereof.

In the Examples, physical properties of contact lenses were measured according tothefollowing methods.

(1) Oxygen permeability (cc.cm./cm.sec.mmHg) is measured at350C. in 0.9 % physiological saline buy a film-oxygen gas permeameter os Seikaken type made by Rikaseiki Kogyo Kabushiki Kaisha with respectto a speciman having a diameter of 12.7 mm.

and a thickness of 0.2 mm.

(2) Vickers hardness (7.5 NHv) is measured in an air-conditioned room of 20"C. and 45 %RH bya hardness tester made by Kabushiki Kaisha Akashi Seisakusho with respect to a specimen having a diameter of 12.7 mm. and a thickness of 4.0 mm.

(3) Refractive index (nD20) is measured in an airconditioned room of 20 C. and 45 % RH by an Erma newtypeAbbe's refractometer made by Erma Optical Works Co., Ltd. with respect to a specimen having a diameter of 12.7 mm. and a thickness of 4.0 mm.

(4) Specificgravity(d20) is measured in a distilled water of 20 C. by employing a Mettler directreading balance with respectto a specimen having a diameter of 12.7 mm. and a thickness of 4.0 mm.

(5) Visible ray percenttransmission (%) is measured in a distil led water of 20"C. byAutomatic Recording Spectrophotometer UV-240 made by Shimadzu Corporation with respect to a specimen having a diameter of 12.7 mm. and a thickness of 0.50 mm.

Example 1 There were thoroughly admixed 34 parts oftris (trimethylsiloxy) silylpropyl methacrylate, 60 parts of 2,2,2 -trifluoroethyl methacrylate, 6 parts of ethylene glycol dimethacrylate and 0.15 part of 2,2' - azobis (2,4-dimethylvaleronitrile) (hereinafter referred to as "ABDVN") as a polymerization initiator. The mixture was placed in a glasstesttube, and afterstoppering the test tube, the polymerization was stepwise carried out in a circulating thermostatat35 C. for41.5 hours and in a circulating dryer at 50"C.for 6 hours, at 60"C.

for 1.5 hours, at700C. for 1.5 hours, at800C. for 1.5 hours, at 90"C. for 1 hour, at 1 OO"C. forl hour and at 11 00C. for 1 hour. The obtained colorless transparent copolymerwascutandsubjectedto mechanical processing such as grinding and polishing to give a hard contact lens.

Physical propertiesofthe lens were measured. The results are shown in Table 1. Physical properties of a conventional oxygen permeable hard contact lens (commercially available underthe commercial name "menicon 2" made byToyo Contact Lens Co., Ltd.) are also shown in Table 1 for comparison.

Table 1 Example 1 Menicon O2 Oxygen permeability 4.27 x 10-10 1.05 x 10-10 Vickers hardness 8.7 8.6 Refractive index 1.427 1.481 Specific gravity 1.23 1.125 Visible ray percent transmission > 98 > 98 The contact lenses obtained in this Example were continuously worn on each ofthe right eyes of 3 albino rabbitsfor 21 days. No change was observed on the corneal surfaces and also no decrease of glycogen was observed. Further, in respect of the histological observation, there was no vascu larization, substantial edema and infiltration of inflammatory cells, and no morphologically significant change was observed between the right eye and the comparative left eye. Thus, the contact lens had an excellent wearability.

It would be understood from the above results that hard contact lens prepared in this Example has a far higher oxygen permeabilitythan the conventional contact lens as well as desirable hardness and rigidity, and also the durability and safety as a contact lens are sufficiently satisfactory.

Examples 2 and 3 The procedures of Example 1 were repeated except that the respective components used in Example 1 were used in amounts shown in Table 2 to give hard contact lenses.

The resu Its ofthe measurement of physical properties ofthe obtained lenses are shown in Table 2.

Table 2 Ex. 2 Ex. 3 Components (part) Tris(trimethylsiloxy)silyl- 24 74 propyl methacrylate 2,2,2-Trifluoroethyl methacrylate 70 20 Ethylene glycol dimethacrylate 5 6 ABDVN 0.12 0.27 Physical properties Oxygen permeability 3.26 x 10-10 7.42 x 10-10 Vickers hardness 10.6 3.3 Visible ray percent transmission > 98 > 98 Comparative Examples 1 to 3 The procedures of Examples 1 to 3 were repeated except that 2,2,2 - trifluoroethyl methacrylate in each Example was replaced with ethyl methacrylate which had a similar structure to the trifluoroethyl methacrylate, so as to correspond to Examples 1 to 3.

The results ofthe measurement of physical properties ofthe obtained contact lenses are shown in Table 3.

Table 3 Com. Ex. 1 Com. HE. 2 Com. Ex. 3 Components (part) Tris(trimethylsiloxy)silyl- 34 24 74 propyl methacrylate Ethyl methacrylate 60 70 20 Ethylene glycol dimethacrylate 6 6 6 ABDVN 0.15 0.12 0.27 Physical properties Oxygen permeability 2.22 x 10-10 1.45 x 10-10 5.72 x 10-10 Vickers hardness 8.6 9.6 3.7 Visible ray percent transmission > 88 > 88 > 98 As is clearfrom comparison between Examples 1 to 3 and Comparative Examples 1 to 3, the hard contact lenses of Examples 1 to 3 obtained by using 2,2,2 trifluoroethyl methacrylate have a far higher oxygen permeability than the hard contact lenses of Comparative Examples 1 to 3 obtained by using an equal amount of ethyl methacrylate instead of the trifluoroethyl methacrylate, while maintaining the same degree of Vickers hardness.

Examples 4 to 15 The procedures of Example 1 were repeated except that the kinds and amounts of components in the polymerization were changed as shown in Table 4.

The physical properties ofthe obtained contact lenses are shown in Table 4.

Table 4 Ex. No. 4 5 6 7 8 9 Components (part) Tris(trimethylsiloxy)silylpropyl methacrylate 50 40 45 45 45 45 2,2,2-Trifluoroethyl methacrylate 50 50 25 25 25 25 Ethyl methacrylate........................ - - 25 - - Isopropyl methacrylate ................... - - - 25 - t-Butyl methacrylate - - - - 25 Cyclohexyl methacrylate - - - - - 25 Tetrahydroforfaryl methacry late Benzyl methacrylate ............. - - - - - - Styrene ~ - - - - - - .Methyl'methacrylate - - - - - 2-Hydroxyethyl methacrylate .............. - - - - - N-Vinyl pyrrolidone ...................... - - - - - Ethylene glycol dimethacrylate ........... - 10 - - - Trimethylolpropane trimethacrylate ....... - - 5 5 5 Allyl methacrylate - - - - - S ABDVN ............................ 0.20 0.17 0.18 0.18 0.18 0.18 Physical properties Oxygen permeability (X 10 10) 6.34 5.29 4.63 4.70 5.12 4.21 Vickers hardness ................. 4.4 8.9 7.3 7.7 7.5 5.4 Visible ray percent transmision ........... > 98 > 98 > 98 > 98 > 98 > 98 - continued - - continued Ex.No. 10 11 12 13 14 15 Components (part) Tris(trimethylsiloxy)silylpropyl methacrylate 45 45 45 55 55 16.8 2,2,2-Trifluoroethyl methacrylate .......... 25 25 25 30 30 70 Ethyl methacrylate - - - - - - Isopropyl methacrylate - - - - - - t-Butyl methacrylate ................. - - - - - Cyclohexyl methacrylate .............. - - - - - Tetrahydrofurfuryl methacrylate ...... 25 - - - - Benzyl methacrylate .................. - 25 - - - Styrene .............................. - - 25 - - Methyl methacrylate b - - - - - 7.2 2-Hydroxyethyl methacrylate - - - 10 - N-Vinyl pyrrolidone - - - - 10 Ethylene glycol dimethacrylate................ - 5 3 5 5 6 Trimethylolpropane trimethacrylate .......... - - - - - Allyl methacrylate .......................... 5 - 2 - - ABOVE 0.18 0.18 0.18 0.22 0.22 0.09 Physical properties Oxygen permeability (X 10-10)................ 4.16 4.69 3.97 5.14 5.30 2.48 Vickers hardness ........................ 4.4 6.1 7.8 6.9 6.6 12.7 Visible ray percent transmission > 98 > 98 > 98 > 98 > 98 > 98 > 98 Examples 16 to 50 The procedures of Example 1 were repeated except thatthe kinds and amounts of components in the polymerization were changed as shown in Table 5.

The physical properties ofthe obtained contact lenses are shown in Table 5.

The organosilane and organosiloxane compounds S1 to S15 andthefluoroalkyl methacrylates and acrylates F1 to Fl 6 shown in Table 5 are as follows: S1: Tris (trimethylsiloxy) silylpropyl methacrylate S2: Pentamethyldisiloxanylmethyl methacrylate S3; Methylbis (trimethylsiloxy) silylpropyl methacrylate S4: Mono [methylbis (trimethylsiloxy) siloxyl bis (trimethylsiloxy) silylpropyl methacrylate S5: Tris [methylbis (trimethylsiloxy) siloxy] silylpropyl methacrylate S6: Methylbis (trimethylsiloxy) silylpropylglycerol methacrylate S7: Tris (trimethylsiloxy) silylpropylglycerol methacrylate S8: Mono [methylbis (trimethylsiloxy) siloxy] bis (trimethylsiloxy) silylpropylglycerol methacrylate S9: Methylbis (trimethylsiloxy) silylpropylglycerol acrylate S10:Trimethylsilylethyltetramethyldisiloxanyl propylglycerol methacrylate S11: Trimethylsilylmethyl methacrylate S12: Trimethylsilylpropyl methacrylate S13: Methylbis (trimethylsiloxy) silylethyltetramethyldisiloxanylmethyl methacrylate S14: Tetramethyltriisopropylcyclotetrasiloxanyl propyl methacrylate S15: Tetramethyltriisopropylcyclotetrasiloxy bis (trimethylsiloxy) silylpropyl methacrylate F1: 2,2,2-Trifluoroethyl methacrylate F2: 2,3,4,5,5,5-Hexafluoro-2,4-bis (trifluoromethyl) pentyl methacrylate F3: 2,2,3,3-Tetrafluoropropyl methacrylate F4: 2,2,3,3-Tetrafluoro-t-anyl methacrylate F5: 2,2,3,4,4,4- Hexafluorobutyl methacrylate F6: 2,2,3,4,4,4- Hexafluoro -t - hexyl methacrylate F7: 2,2,3,3,4,4,5,5 - Octafluoropentyl methacrylate F8: 2,3,4,5,5,5- Hexafluoro-2,4- bis (trifluoromethyl) pentyl methacrylate F9: 2,2,3,3,4,4,5,5,6,6,7,7-Dodecafluoropentyl methacrylate F10: 2-Hydroxy-4,4,5,5,6,7,7,7-octafluoro-6trifluoro - methylheptyl methacrylate F11:2-Hydroxy-4,4,5,5,6,6,7,7,8,9,9,9- dodecafluoro-8-trifluoromethylnonyl methacrylate F12:2-Hydroxy-4,4,5,5,6,6,7,7,8,8,9,9,10,11,11, 11-hexadecafluoro- 10-trifluoromethylundecyl methacrylate F13: 2,2,3,3-Tetrafluoropropyl acrylate F14: 2,2,3,3,4,4,5,5 - Octafluoropentyl acrylate F15:2-Hydroxy-4,4,5,5,6,6,7,7,8,9,9,9- dodecafluoro - 8 - trifluoromethylnonyl acrylate F16:2-Hydroxy-4,4,5,5,6,6,7,7,8,8,9,9,10,11,11, 11 - hexadecafluoro -10 -trifluoromethylundecyl acrylate Table 5 Ex.No. 16 17 18 19 20 21 22 23 Components (part) Si-(M)A..... S1 64 51 54 S1 44 S2 30 S3 30 51 30 S4 30 S5 30 P-(M)A........ F1 30 F1 40 F1 50 F1 50 F1 50 F1 50 F1 50 F1 50 Methyl methacrylate.. - - - 12 12 12 12 12 Ethylene glycol 6 6 6 8 8 8 8 8 dimethacrylate.....

ABDVN....... 0.24 0.21 0.18 0.15 0.15 0.15 0.15 0.15 Physical properties Oxygen permeability (x 10-10)..... 6.59 6.03 5.33 2.15 2.57 3.76 3.93 4.47 Vickers hardness 4.9 5.9 7.3 . 11.8 10.1 11.2 10.2 9.5 Visible ray percent transmission.... > 98 > 98 > 98 > 98 > 98 > 98 > 98 > 98 - continued - continued Ex. No. 24 25 26 27 28 29 30 31 Components (part) Si-(M)A......... SO 30 57 30 S8 30 S9 30 810 30 511 30 S12 30 S13 30 F-(M)A............ F1 50 F1 50 F1 50 F1 50 F1 50 F1 50 Fl 50 F1 50 Methyl methacrylate 12 12 12 12 12 12 12 12 Ethylene glycol 8 8 8 8 8 8 8 8 dimethacrylate......

ABDVN............ 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Physical properties Oxygen permeability (X 10-10)......... 1.59 2.29 2.57 1.68 1.58 1.20 1.31 3.21 Vickers hardness 11.2 11.6 9.1 8.2 5.0 16.7 14.2 7.3 Visible ray percent transmission > 98 > 98 > 98 > 98 > 98 > 98 > 98 > 98 - continued - continued Ex. No. 32 33 34 35 36 37 : 38 39 Components (part) Si-(M)A............... 814 30 515 30 57 30 812 30 51 40 S1 40 51 40 S1 40 F-(M)A F1 50 F1 50 F2 40 F2 40 F1 30 F3 30 F4 30 F5 30 Methyl methacrylate 12 12 22 22 22 22 22 22 Ethylene glycol 8 8 8 8 8 8 8 8 dimethacrylate........

ABDVN............ 0.15 0.15 0.15 0.15 0.20 0.20 0.20 0.20 Physical properties Oxygen permeability (x 10-10)....... 2.04 2;04 2.49 1.28 3.86 3.43 3.01 3.73 Vickers hardness 8.3 8.3 11.4 13.9 10.8 10.0 12.1 9.1 Visible ray percent transmission............ > 98 > 98 > 98 > 98 > 98 > 98 > 98 > 98 - continued - continued Ex. No. 40 41 42 43 44 45 : 46 47 Components (part) Si-(M)A........ 51 40 51 40 51 40 51 40 51 40 51 40 Sl 40 S1 40 F-(M)A........ F5 30 F7 30 F8 30 F9 30 F10 30 F11 30 F12 30 F13 30 Methyl methacrylate.. 22 22 22 22 22 22 22 22 Ethylene glycol 8 8 8 8 8 8 8 8 dimethacrylate ABDVN...... 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Physical properties Oxygen permeability (X 10-10)...... 3.79 3.37 4.23 3.74 4.10 4.18 5.02 2.95 Vickers hardness...... 11.3 8.8 9.7 8.5 9.4 8.2 8.4 5.8 Visible ray percent > 98 > 98 > 98 > 98 > 98 > 98 > 98 > 98 transmission.......

- continued -continued Ex. No. 48 49 50 Components (part) Si-(M)A S1 40 S1 40 S1 40 F-(M)A........ F14 30 FIS 30 F16 30 Methyl methacrylate. . 22 22 22 Ethylene glycol 8 8 dimethacrylate........ 8 8 8 ABDVM......... 0.20 0.20 0.20 Physical properties Oxygen permeability (x 10-10)........... 3.68 4.15 4.94 Vickers hardness 6.8 7.4 7.7 Visible ray percent transmission > 90 > 98 > 98 In addition to the ingredients used in the Examples, other ingredients can be used in the Examples asset forth in the specification to obtain substantially the same results.

Claims (4)

1. An oxygen permeable hard contact lens made of a copolymer comprising (a) an organosilane or organosiloxane compound having in one molecule at least one group of the generalformula (I):

wherein R1 is hydrogen atom or methyl group, K is 0 or 1, and I is 1 or3, and having at most 16 silicon atoms, and (b) a compound of the general formula (II):

wherein R1 is as defined above, mis 0 or 1, n is 0 or an integer of 1 to 3, and Rf is a straight or branched flouroalkyl group having 2 to 21 fluorine atoms.

2. The contact lens of Claim 1, werein the organosiloxane is a compound ofthe general formula (III):

wherein R1 is hydrogen atom or methyl group, k : is 0 or 1, I is 1 or3,X1, Y1 and Z1 are the same or different and each is-CH3 or-O-Si(Ch3)3, and a is 2 or3.

3. An oxygen permeable hard contact lens made of a copolymer substantially as described in anyone ofthe examples 1 to 20 disclosed herein.

3. The contact lens of Claim 1 wherein the organosilane or organosiloxane is a compound ofthe general formula (IV):

wherein R1 is hydrogen atom or methyl group, kis 0 or 1, lis 1 or3, R2, R3 and R4 are an alkyl group having 1 to3carbonatoms,0 < a < 4,andO6b,c,d < 4, provided 0 < a+b+c+d 44.

4. The contact lens of Claim 3, wherein the compound (IV) is a compound ofthe general formula (V):

wherein R' is hydrogen atom or methyl group, k is 0 or 1, is 1 or 3, and X2, Y2 and Z2 are the same or different and each is-CH2,

in which ss is an integer of 2 to

4.

5. The contact lens of Claim 3, wherein the compound (IV) isa compound of the general formula (Vl):

wherein R1 is hydrogen atom or methyl group, kis 0 -or1,1is1 or3andyisanintegerof2to4.

6. The contact lens of Claim 1, wherein said Rfis a perfluoroalkyl group-ofthe general formula (VII): CpF2p+1 (VII) wherein p is an integer of 1 to 10.

7. The contact lens of Claim 1 wherein said Rf is a fluoroalkyl group ofthe general formula (VIII): -CpF2pH (VIII) wherein p isan integerof 1 to 10.

8. An oxygen permeable hard contact lens made of a copolymer substantially as described in anyone ofthe examples disclosed herein.

Claims 1-8 above have been deleted ortextually amended.

New ortextually amended claims have been filed as follows: CLAIMS

1 . An oxygen permeable hard contact lens made of a copolymer comprising tris (trimethylsiloxy) silylpropyl methacrylate of the formula (I):

and 2,2.2, -trifluoroethyl methacrylate ofthe formula (II):

2. The contact lens of Claim 1, wherein the ratio of tris (trimethylsiloxy) silylpropyl methacrylate to 2,2,2, -trifluoroethyl methacrylateisfrom 15: 85to80 :20 by weight.