JPS6336646B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to oxygen permeable rigid contact lenses. Contact lenses currently on the market are soft contact lenses made of water-absorbing polymers such as poly(2-hydroxyethyl methacrylate) and soft hydrophobic polymers such as silicone rubber, and soft contact lenses made of hard polymers such as poly(methyl methacrylate). They are broadly classified into hard contact lenses. Among these, hard contact lenses are generally inferior to soft contact lenses in terms of comfort when worn on the eyes, but hard contact lenses have superior vision correction effects, durability, and are easier to handle. It is still widely used today because it has many unique advantages. A major drawback of rigid contact lenses is that it is difficult to supply the oxygen necessary for the metabolism of the corneal (black eye) tissue from the atmosphere to the cornea through the contact lens material (oxygen permeability). Tissue metabolic disorders may occur. However, in recent years, the above problem has been solved to some extent with the advent of oxygen permeable hard contact lenses made from copolymers of methyl methacrylate and specific methacrylates that have siloxane bonds (Si-O bonds) in the molecule. Clinical evaluation of rigid contact lenses is increasing. However, in general, copolymers whose main component is methacrylate containing siloxane bonds are less hard and hard than poly(methyl methacrylate), which is the material for ordinary rigid contact lenses, and are also brittle. be. hardness of the material,
Insufficient hardness tends to cause scratches on the lens surface, and also makes it difficult to manufacture lenses of a certain quality that conform to the standard shape of the lens. On the other hand, the brittleness of the material impairs machinability, increases the breakage rate of the lens, and is a factor that reduces durability. Therefore, in order to obtain an oxygen-permeable hard contact lens that has the desired hardness and rigidity as a hard contact lens and also has some improvement in brittleness, it is necessary to increase the usage ratio of the siloxane bond-containing methacrylate, which is the main component. On the other hand, the ratio of methyl methacrylate used must be increased, resulting in a dilemma in which the improvement in oxygen permeability in the resulting copolymer is suppressed. The present inventors have solved the drawbacks of the prior art as described above, and have created a hard contact lens made of a material that has desirable hardness and hardness as a hard contact lens and has improved brittleness, compared to the conventional oxygen permeable material. As a result of extensive research to develop a hard contact lens that has higher oxygen permeability than other hard contact lenses, we have developed a lens that contains siloxane bond-containing acrylate or siloxane bond-containing methacrylate and fluoroacrylate or fluoroalkyl methacrylate as the main components. The present inventors have discovered that using a copolymer as a material for contact lenses is extremely effective in achieving the above objectives, and have completed the present invention. That is, the present invention is based on the general formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l indicates 1 or 3) Number of Si atoms containing at least one group in one molecule
16 or less organosilanes or organosiloxanes (hereinafter collectively abbreviated as Si-(M)A)
And the general formula (): (In the formula, R ¹ is the same as above, m is 0 or 1, n
is an integer of 0 or 1 to 3, and R _f is a linear or branched fluoroalkyl group having 2 to 21 fluorine atoms). (generally abbreviated as F-(M)A) (however, if an alkyl ester of methacrylic acid or acrylic acid is used in the copolymer, 100 parts by weight of the total monomer mixture) In addition, the combination of tris(trimethylsiloxy)silylpropyl methacrylate in general formula () and 2,2,2-trifluoroethyl methacrylate in general formula () is excluded from the copolymerization component) The present invention relates to an oxygen permeable hard contact lens comprising: As Si-(M)A represented by the general formula (), the general formula (): (In the formula, R ¹ , k, l are the same as above, α is 2 or 3, X ₁ , Y ₁ , Z ₁ are the same or different -CH ₃
or

[Formula]) or general formula (): (In the formula, R ¹ , k, l are the same as above, R ² , R ³ , R ⁴
is an alkyl group having 1 to 3 carbon atoms, 0<
a<4, 0≦b, c, d<4 (but 0<a+b
+c+d≦4). Among those represented by the general formula (), preferred are the general formula (): (In the formula, R ¹ , k, l are the same as above, X ₂ , Y ₂ , Z ₂
are the same or different −CH ₃ ,

【formula】

【formula】

【formula】

【formula】 or

[Formula] (where β is an integer from 2 to 4)) or the general formula (): (In the formula, R ¹ , k, l are the same as above, γ is 2 to 4
(indicates an integer of ). Also, F-(M)A represented by the general formula ()
The substituent R _f is a perfluoroalkyl group represented by the general formula (): -C _p F _2p+1 () (wherein p is an integer of 1 to 10), or a perfluoroalkyl group represented by the general formula () A fluoroalkyl group represented by: -C _p F _2p H () (in the formula, p is the same as above) is preferred. Si-(M)A used in the present invention is as described above, but in the general formula (), those in which R ¹ is a methyl group are higher in hardness and have lower heat resistance. It is preferably used because of its good properties. Regarding k, a material with a value of 0 has higher oxygen permeability than a material with a value of 1, and the hardness of the material also improves. However, in terms of copolymerizability with hydrophilic monomers, those having a value of 1 are better. Regarding l, those with 3 are chemically more stable than those with l. Si-(M)A is an organosilane or organosiloxane having 16 or less Si atoms, and has a linear, branched, or cyclic silyl group or siloxanyl group as described above, and has a number of Si atoms. The larger the number of Si atoms, the better the oxygen permeability, but at the same time the material becomes soft and brittle, so it is desirable to have about 4 to 10 Si atoms. Further, branched and cyclic ones are more rigid than straight-chain ones, and those having a siloxanyl group have better oxygen permeability than a silyl group, so they are preferably used. Regarding F-(M)A, in the general formula (), those in which R ¹ is a methyl group have higher hardness and better heat resistance than those in which R 1 is a hydrogen atom, and are therefore preferably used. With regard to m, a material with a value of 0 has a higher oxygen permeability than a material with a value of 1, and the hardness of the material also improves. However, in terms of copolymerizability with hydrophilic monomers, those having a value of 1 are better. Also, there is not much difference in physical properties when n is 0 or an integer from 1 to 3, but (the shorter and branched C _O H _2o is, the harder it is. Therefore, it is preferably 0 or 1. R _f is a linear or branched fluoroalkyl group having 2 to 21 fluorine atoms, and the larger the number of fluorine atoms, the higher the oxygen permeability. However, at the same time, it becomes soft and brittle, so it is desirable to have about 2 to 5 fluorine atoms.Also, a branched chain type is preferable because it is harder than a straight chain type. Furthermore, for both Si-(M)A and F-(M)A monomers, methacrylate has higher hardness than acrylate, and also has better light resistance and chemical resistance. Specific examples of Si-(M)A include pentamethyldisiloxanyl methyl methacrylate,
Pentamethyldisiloxanyl methyl acrylate, pentamethyldisiloxanylpropyl methacrylate, pentamethyldisiloxanylpropyl acrylate, methylbis(trimethylsiloxy)silylpropyl methacrylate, methylbis(trimethylsiloxy)silylpropyl acrylate, tris(trimethylsiloxy) Silylpropyl methacrylate, Tris(trimethylsiloxy)silylpropyl acrylate, Mono[methylbis(trimethylsiloxy)siloxy]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)silylpropylglycerol methacrylate, mono[methylbis(trimethylsiloxy)siloxy]bis(trimethylsiloxy)silylpropylglycerol acrylate, trimethylsilylethyltetramethyldisiloxanylpropylglycerol methacrylate, trimethylsilylethyltetramethyldisiloxanylpropylglycerol Acrylate, trimethylsilylmethyl methacrylate, trimethylsilylmethyl acrylate, trimethylsilylpropyl methacrylate, trimethylsilylpropyl acrylate, methylbis(trimethylsiloxy)silylethyltetramethyldisiloxanylmethylmethacrylate, methylbis(trimethylsiloxy)silylethyltetramethyldisiloxanylmethylacrylate, Tetramethyltriisopropylcyclotetrasiloxanylpropyl methacrylate, Tetramethyltriisopropylcyclotetrasiloxanylpropyl acrylate, Tetramethyltriisopropylcyclotetrasiloxybis(trimethylsiloxy)silylpropyl methacrylate, Tetramethyltriisopropylcyclotetrasiloxybis(trimethyl siloxy)silylpropyl acrylate, etc., and it is preferable to select and use one or more types from these. As a specific example of F-(M)A, for example, 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-1-trifluoromethylethyl acrylate, 2,2,3,3-tetrafluorotertiaryamyl methacrylate, 2 , 2,3,3-tetrafluorotertiary amyl acrylate, 2,
2,3,4,4,4-hexafluorobutyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,4,
4,4-hexafluorotahexyl methacrylate, 2,2,3,4,4,4,-hexafluorotahexyl 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-hexyfluoro-2,4-bis(trifluoromethyl)
Pentyl 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-hydroxy 4,4,
5,5,6,7,7,7-octafluoro-6-
Trifluoromethylheptyl methacrylate, 2
-Hydroxy-4,4,5,5,6,7,7-octafluoro-6-trifluoromethylheptyl acrylate, 2-hydroxy-4,4,5,
5,6,6,7,7,8,9,9,9-dodecafluoro-8-trifluoromethylnonyl methacrylate, 2-hydroxy-4,4,5,5,6,
6,7,7,8,9,9,9-dodecafluoro-
8-trifluoromethylnonyl acrylate, 2
-Hydroxy-4,4,5,5,6,6,7,
7,8,8,9,9,10,11,11,11-hexadecafluoro-10-trifluoromethylundecyl methacrylate, 2-hydroxy-4,4,5,
5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 11,
Examples include 11,11-hexadecafluoro-10-trifluoromethylundecyl acrylate,
It is preferable to select and use one or more types from these. Among them, the formula () as Si-(M)A: Tris(trimethylsiloxy)silylpropyl methacrylate, represented by formula () Pentamethyldisiloxanylpropyl methacrylate of the formula (XI): Methylbis(trimethylsiloxy)silylpropyl methacrylate represented by formula (XII) as F-(M)A: 2,2,2-trifluoroethyl methacrylate represented by formula (): 2,2,3,3-tetrafluoropropyl methacrylate, represented by the formula (): 2,2,3,3,3-pentafluoropropyl methacrylate or formula (): When using 2,2,2-trifluoro-1-trifluoromethylethyl methacrylate shown in the following, a copolymer particularly excellent in oxygen permeability, hardness, and hardness can be obtained. When F-(M)A used in the present invention is copolymerized with Si-(M)A, for example, compared to ordinary alkyl methacrylates and alkyl acrylates having a similar chemical structure to the monomer, It is possible to make a material with higher oxygen permeability, thereby imparting high oxygen permeability and desired hardness and hardness to the copolymer obtained without drastically increasing the amount of Si-(M)A used. It becomes possible. Moreover, when using the above F-(M)A,
When using alkyl methacrylate or alkyl acrylate, the heat resistance as a copolymer is improved, and n-hexane (non-polar solvent), ethyl alcohol (polar solvent), acetone (ampholytic solvent)
It also improves chemical resistance. Si- which is the main component of the copolymer in the present invention
The usage ratio of (M)A and F-(M)A is approximately
15:85-80:20, more preferably about 30:70-70:
A range of 30 is recommended. If the amount of Si-(M)A used is greater than the above range, the resulting copolymer will be soft and brittle, resulting in poor machinability and poor chemical resistance. On the other hand, if the amount is less than the above range, sufficient oxygen permeability cannot be imparted to the resulting copolymer, which is not preferable. In addition to these essential monomer components, various monomers can be used as copolymerization components in the copolymer according to the present invention, and the properties of the copolymer can be modified for various purposes. Alkyl esters of methacrylic acid or acrylic acid are particularly effective for increasing the strength of the copolymer and improving its durability as a contact lens. Specific examples of such alkyl esters of methacrylic acid or acrylic acid include 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,
Examples include cyclohexyl acrylate, and it is preferable to select and use one or more of them. The amount used is preferably in the range of about 0 to less than 30 parts based on 100 parts (parts by weight, the same applies hereinafter) of the total monomer mixture to be subjected to copolymerization. Furthermore, monomers having the same effect as those alkyl esters of methacrylic acid or acrylic acid include styryl compounds such as styrene, alkyl esters of itaconic acid or crotonic acid,
glycidyl methacrylate, glycidyl acrylate, tetrahydrofurfuryl methacrylate,
Examples include tetrahydrofurfuryl acrylate and benzyl methacrylate, which can be used in the same amount as the alkyl ester of methacrylic acid or acrylic acid. For the purpose of stabilizing the standard and shape of contact lenses and improving chemical resistance,
Crosslinking monomers are effective. Specific examples of such crosslinkable monomers include ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, allyl acrylate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate. It is preferable to select and use one or more types from these. The amount used is approximately 0 to 100 parts of the total monomer mixture used for copolymerization.
Preferably it is in the range of 20 parts, more preferably about 1 to 10 parts. The use of hydrophilic monomers is effective for imparting hydrophilicity to the resulting copolymer and producing hard contact lenses with good water wettability. Examples of such hydrophilic monomers include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, N-vinylpyrrolidone, and dimethylacrylamide, and it is preferable to select and use one or more of these. The amount used is based on the total monomer mixture used for copolymerization.
About 0 to 30 parts out of 100 parts, more preferably about 5 to 15 parts
It is preferable to set it as the range of . If these hydrophilic monomers are used in a large amount exceeding the above range, the resulting copolymer will become water-containing, and the water will plasticize the copolymer and make it soft. This is not preferable because the contact lens begins to show properties of hardness and loses its properties as a hard contact lens. Instead of or in addition to the use of the hydrophilic monomer, the surface of the obtained hard contact lens may be modified, for example, by subjecting the obtained rigid contact lens to a corona discharge or plasma discharge, or by treating it with a strong acid such as hydrochloric acid or nitric acid. It is also possible to impart effective hydrophilic properties. The method for copolymerizing the monomer mixture as described above can be easily carried out by a method commonly used in the art. For example, a radical polymerization initiator commonly used in the polymerization of unsaturated hydrocarbon compounds can be used, and the polymerization can be carried out at a temperature of room temperature to about 130°C. Specific examples of radical polymerization initiators that can be used include benzoyl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile, etc., and one or more of these can be selected and used. do. The amount used is suitably in the range of 0.01 to 1 part based on 100 parts of the total monomer mixture to be subjected to copolymerization. Molding into contact lenses can also be carried out by conventional methods. For example, copolymerization can be carried out in a mold corresponding to the shape of a contact lens, directly molded into the shape of a contact lens, and if necessary, this can be mechanically finished. Copolymerization is carried out in an appropriate mold or container to obtain a block, plate, or round rod-shaped material, which is then molded into a contact lens of the desired shape by ordinary mechanical processing such as cutting and polishing. You can also. The oxygen permeable contact lens of the present invention obtained as described above exhibits the following excellent properties. (a) Desirable hardness for hard contact lenses;
This is a hard contact lens made of a material that is both hard and has improved brittleness. (b) It also has higher oxygen permeability than conventional oxygen permeable hard contact lenses. Next, the contact lens of the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited only to these Examples. Example 1 34 parts of tris(trimethylsiloxy)silylpropyl methacrylate, 60 parts of 2,2,2-trifluoroethyl methacrylate, 6 parts of ethylene glycol dimethacrylate, and 2,2'-azobis-(2,4- 0.15 part of dimethylvaleronitrile) was mixed well and poured into a glass test tube, which was then sealed with a stopper. This was placed in a circulating constant temperature water tank and polymerized at 35℃ for 41.5 hours.
6 hours at 50℃ and 1.5 hours at 60℃ in a circulation dryer.
1.5 hours at 70℃, 1.5 hours at 80℃, 1 hour at 90℃,
Heat polymerization was carried out stepwise at 100°C for 1 hour and at 110°C for 1 hour. The obtained colorless and transparent copolymer was cut and mechanically processed by cutting and polishing to obtain a hard contact lens. In addition, each physical property value was measured according to the following method. (1) Oxygen permeability coefficient [cc・cm/cm ²・sec・mmHg] was measured using a Seikaken film oxygen permeability meter manufactured by Rika Seiki Kogyo Co., Ltd. in 0.9% physiological saline at 35°C.
Measurements were made on a test piece with a diameter of 12.7 mm and a thickness of 0.2 mm. (2) Bitkers hardness [7.5NHv] was measured using a hardness meter manufactured by Akashi Seisakusho Co., Ltd. on a test piece with a diameter of 12.7 mm and a thickness of 4.0 mm in a constant temperature and humidity room at 20°C and 45% RH. (3) The refractive index [n ²⁰ _D ] was measured using a new Elma Atsube refractometer manufactured by Elma Optical Co., Ltd., and a diameter of 12.7 mm and thickness of 4.0 mm was measured in a constant temperature and humidity room at 20°C and 45% RH. Measurements were made on the pieces. (4) Specific gravity [d ²⁰ ] is determined using a Mettler direct balance.
Measurements were made on a test piece with a diameter of 12.7 mm and a thickness of 4.0 mm in distilled water at 20°C. (5) Visible light transmittance [%] was measured at 20°C using a Shimadzu self-recording spectrophotometer UV-240 manufactured by Shimadzu Corporation.
Measurements were made on a test piece with a diameter of 12.7 mm and a thickness of 0.50 mm in distilled water. The results obtained are shown in Table 1. For comparison, the product name is Menicon O ₂ (Toyo Contact Lens Co., Ltd.).
Table 1 also lists the physical properties of a commercially available oxygen-permeable hard contact lens known as a commercially available oxygen-permeable hard contact lens.

[Table] When the contact lenses obtained in this example were worn continuously on the right eyes of three white rabbits for 21 days,
No abnormalities were observed on the corneal surface, and no decrease in glycogen levels was observed.
Furthermore, histological findings showed no angiogenesis, substantial edema, or inflammatory cell infiltration, and no significant morphological changes were observed between the control eye and the left eye, indicating extremely good wearability. showed that. In this way, the hard contact lens produced in this example has desirable hardness and hardness, and also exhibits much higher oxygen permeability than conventional products, and is also sufficiently durable and safe as a contact lens. It was satisfying. Examples 2 to 3 Hard contact lenses were produced by polymerization and processing in the same manner as in Example 1, except that each component used in Example 1 was used in the amounts shown in Table 2. Table 2 also shows the measurement results of the physical properties of the obtained hard contact lens.

【table】

[Table] Comparative Examples 1 to 3 Corresponding to Examples 1 to 3 above, except that 2,2,2-trifluoroethyl methacrylate was replaced with the same amount of ethyl methacrylate having a chemical structure similar to the monomer. Polymerization and processing were carried out in the same manner as in Examples 1 to 3, respectively, to produce hard contact lenses. The results of measuring the physical properties of the obtained hard contact lenses are shown in the third
Shown in the table.

[Table] As can be seen by comparing Examples 1 to 3 and Comparative Examples 1 to 3 above, hard contact lenses obtained using 2,2,2-trifluoroethyl methacrylate (Examples 1 to 3) maintains the same Vickers hardness as hard contact lenses obtained by using the same amount of ethyl methacrylate in place of 2,2,2-trifluoroethyl methacrylate (Comparative Examples 1 to 3), and It exhibited significantly higher oxygen permeability than the products obtained in Examples 1 to 3. Examples 4 to 50 Each component and its usage amount in copolymerization
Experiments were conducted in the same manner as in Example 1, except as shown in the table, and the desired hard contact lenses were obtained. Their respective physical property values are also shown.

【table】

Claims (1)

[Claims] 1 General formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l is 1 or 3) Number of Si atoms containing at least one group in one molecule
Up to 16 organosilanes or organosiloxanes with general formula (): (In the formula, R ¹ is the same as above, m is 0 or 1, n
is an integer of 0 or 1 to 3, and R _f is a linear or branched fluoroalkyl group having 2 to 21 fluorine atoms). However, if an alkyl ester of methacrylic acid or acrylic acid is used in the copolymer, the amount is less than 30 parts by weight in 100 parts by weight of the total monomer mixture, and tris(trimethylsiloxy)silyl in the general formula () is used. An oxygen-permeable hard contact lens comprising a combination of propyl methacrylate and 2,2,2-trifluoroethyl methacrylate in general formula (2) (excluding the copolymerization component). 2. The oxygen permeable hard contact lens according to claim 1, wherein the ratio of organosilane or organosiloxane to the compound represented by the general formula () is in the range of about 15:85 to 80:20 by weight. . 3 Organosiloxane has the general formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l is 1 or 3, X ₁ , Y ₁ and Z ₁ are the same or different, -CH ₃ or [Formula] α is 2 or 3) Claim 1 Oxygen-permeable rigid contact lens described in . 4 Organosilane or organosiloxane has the general formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l is 1 or 3, R ² , R ³ , R ⁴ is 1 to
Alkyl group with 3 carbon atoms, 0<a<
4, 0≦b, c, d<4 (however, 0<a+b+c
The oxygen-permeable hard contact lens according to claim 1, which is represented by +d≦4). 5 Organosilane or organosiloxane has the general formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l is 1 or 3, X ₂ , Y ₂ and Z ₂ are the same or different -CH ₃ , [formula] [formula] [formula] [formula] or [formula] (where β is 2 to 4 5. The oxygen permeable hard contact lens according to claim 4, which is represented by (integer)). 6 Organosiloxane has the general formula (): (In the formula, R ¹ is a hydrogen atom or a methyl group, k is 0
or 1, l is 1 or 3, γ is an integer from 2 to 4)
The oxygen permeable hard contact lens according to claim 4, which is represented by: 7. The compound according to claim 1, wherein R _f is a perfluoroalkyl group represented by the general formula (): -C _p F _2p+1 () (wherein p represents an integer of 1 to 10) Oxygen permeable rigid contact lens. 8. The oxygen permeable device according to claim 1, wherein R _f is a fluoroalkyl group represented by the general formula (): -C _p F _2p H () (in the formula, p represents an integer of 1 to 10). Rigid contact lenses.