JPS6264812A - Hydrogel base material - Google Patents

Abstract

PURPOSE:To improve the optical properties, gas permeability and mechanical properties of the obtained hydrogel base material, by polymerizing a mixture essentially consisting of a specified polyester and a (meth)acrylamide. CONSTITUTION:An optically transparent hydrogel base material obtained by polymerizing a mixture essentially consisting of an optically transparent polyester (a) having a MW of about 1,000-100,000 and at least one radical- polymerizable group and a (meth)acrylamide (b) of the formula (wherein R1 is H or CH3 and R2 and R3 are each H or 1-2 C alkyl). Said polyester (a) can be obtained by a reaction of an epoxy compound with a cyclic acid anhydride, and one having at least either of a methacryloyl group and an acryloyl group as the polymerizable group contained therein is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydrogel base material used for a hydrogel material having excellent optical properties, gas permeability and mechanical properties.

[Prior Art] In recent years, as the use of polymeric materials in the medical industry has progressed, interest in hydrophilic polymers has increased, and in particular, polymeric materials that are water-insoluble and have a large water content are becoming increasingly popular as medical materials. It has come to be used in various membrane materials such as catheters, cannulae, hydrous contact lenses, etc.

Such water-containing materials have high water-containing properties by using highly water-containing monomers such as tovinylpyrodridone and N,N-dimethylacrylamide. However, such hydrogels, which are water-insoluble and have a large water content, rapidly decrease their mechanical properties as the water content increases, or even lose transparency when trying to increase gas permeability. However, until now, it has not been possible to obtain a hydrogel that satisfactorily satisfies optical properties, gas permeability, and mechanical properties at the same time.

[Problems to be Solved by the Invention] In view of the above circumstances, the present inventors conducted research to create a hydrogel that has excellent optical properties, gas permeability, and mechanical properties, and is a highly water-containing material. As a result of overlapping, a highly water-containing material with the general formula: (wherein R1 is ■ or CH3:
(R2 and R3 represent ■ or an alkyl group having 1 or 2 carbon atoms) and a polyester having at least one radically polymerizable polymer group in the molecule. The present invention was completed based on the discovery that drogel is preferable for achieving the above object.

[Means for Solving the Problems] That is, the present invention provides an optically transparent molecular weight of about 1000 to 1
A polyester having at least one radically polymerizable polymer group in the molecule of 00000 and the general formula: (wherein, R1 is 1 or CH3: R2 and R3 represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms. ) The present invention relates to an optically transparent hydrogel base material obtained by polymerizing a (meth)acrylamide represented by () as an essential component.

[Function] That is, in the present invention, the general formula of the highly water-containing monomer is: (wherein, R1 is ■ or CH3; f(2 and R3
represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms (hereinafter referred to as A).
By using A (referred to as A m) as an essential component, the water content of the produced hydrogel can be greatly increased. Because it is a polymer with
The polyester having excellent mechanical properties is introduced into the AAn+ polymer by polymerizing well with the polymerizable group of m, and can effectively reinforce the AAI+1 polymer. As a result, the hydrogel obtained by hydrating the hydrogel base material of the present invention has excellent mechanical properties and is macroscopically uniform without phase separation.

Although it is not yet clear in what form the AAm and the polyester having a polymerizable group in the molecule are polymerized in the hydrogel base material of the present invention, it is likely that the polyAAn+ chain and the polyester chain are polymerized with each other. It is thought that they are connected in such a way that they intersect at the polymeric groups of. In this case, if the polyester chain has two or more polymerizable groups, the polyester chain will have crosslinking ability in addition to reinforcing ability, and especially in this case, the polyester chain and the polyAAm chain will be well bonded. This is more preferable because it can crosslink and improve the shape stability of the resulting hydrogel. Next, an example of a polymerization form of a polyester chain into which a polymerization group having a methacryloyl group is introduced as a polymerization group and a polyAAIII chain will be shown.

Polyester chain ``1'', /゛~C=0 CH3 methacryloyl group)
As the polyester having a radically polymerizable polymer group, a grafted polyester is preferable in order to improve the rubber hardness of the resulting hydrogel and obtain a functional hydrogel with high strength despite its high water content. As a method for synthesizing such a grafted polyester, the following reaction between an epoxy compound and a cyclic acid anhydride is preferable from the viewpoint of easy control of the molecular structure etc. since the reaction has alternating copolymerizability. Regarding the amount of epoxy compound and cyclic acid anhydride used in such a reaction, it is recommended to use approximately equimolar amounts of epoxy compound and cyclic acid anhydride in order to control the molecular structure by utilizing alternating copolymerization. is preferred.

Examples of the epoxy compound used in the synthesis of the grafted polyester include components selected from the following groups 1 to 3, and the amounts used of each are also shown.

[Group 1] Oxide, formula (I): R1-CHC82m (wherein, R1 is a hydrogen atom or a linear chain having 1 to 6 carbon atoms,
A branched or cyclic alkyl group, the alkyl group may be substituted with halogen) and an epoxy compound represented by the formula (■): is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and the alkyl group is a group selected from the group consisting of a phenyl group and an optionally halogen-substituted epoxy group. One or more epoxy compounds selected from the group consisting of compounds.

Specific examples of the compound represented by the formula (11 or (I[)) include ethylene oxide, propylene oxide, 1.2-epoxybutane, 1.2-epoxypentane, 1.2-epoxyhexane, 1.2- Examples include epoxy hebutane, 1,2-epoxy octane, methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, and phenyl glycidyl ether.

The amount used is preferably in the range of about 30 to 99 mol% of all the epoxy compounds used in the reaction.

[Group 2] Formula (■): R3-0-CH2CHCH2 \l O(2) (wherein, R3 is a vinyl group, an allyl group, an acryloyl group,
Methacryloyl group, formula: CH2=CH÷0C2H4-+rV (in the formula, n is 2
(representing an integer of ~50), a group represented by the formula: CH2=CH+0C3H6+ (in the formula, m is 2 to 50
(representing an integer of 1 to 50), a group represented by the formula: CH2=CH0Cn H; one or more epoxy compounds selected from the group consisting of epoxy compounds represented by the formula [Vl: CH2=CH+ C to R2 (+ CHCH2 (in the formula, k represents an integer of O to 50) epoxy compound.

Representative examples of the compound represented by formula (8) include allyl glycidyl ether, glycidyl acrylate,
Examples include glycidyl methacrylate, vinyl poly(oxyethylene) glycidyl ether, and vinyl poly(oxypropylene) glycidyl ether.

Representative examples of the compounds represented by 2) include 3.
4-epoxy-1-butene, 4.5-epoxy-1-pentene, 5,6-epoxy-1-hexene, 6.7-epoxy-1-heptene, 7.8-epoxy-1-octene, 8.9- Examples include epoxy-1-nonene and 9.10-epoxy-1-decene.

The amount used is based on all the epoxy compounds used in the reaction.
A range of about 1 to 50 mole percent is preferred.

If the amount used is more than 50 mol%, the number of polymerized groups introduced will increase, and in general, the water content of the resulting hydrogel will decrease and the rubber hardness will decrease, similar to when too much crosslinking is used. This is not a desirable result.

[Group 3] 2M: R4-CHC Old ■) (In the formula, R4 is a linear, branched or cyclic alkyl group having 7 to 20 carbon atoms, and the alkyl group may be substituted with halogen. epoxy compound represented by the formula■
): R5-QC)+2 CHCH2(I)Il (wherein, R5
is a linear, branched or cyclic alkyl group having 7 to 20 carbon atoms which may be substituted with halogen, formula: R' +
0C2Ha11 (wherein R6 is a straight, branched or cyclic alkyl group having 1 to 20 carbon atoms, and the alkyl group is selected from the group consisting of a halogen-substituted or phenyl group) group, a does not represent an integer of 5 to 50) and formula: R740C3H6・Todo(
In the formula, R7 is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and the alkyl group may be substituted with halogen, or) One or more epoxy compounds selected from the group consisting of epoxy compounds represented by (1) representing an integer from 1 to 50.

Representative examples of the epoxy compound represented by the formula M include:
For example, 1,2-epoxynonane, 1,2-epoxyundecane, 1,2-1 boxytridecane, 1,2-epoxypentadecane, 1,2-epoxyheptadecane, 1
, 2-epoxyoctadecane, etc.

Typical examples of the epoxy compound represented by formula (2) include 2-ethylhexyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, and pentadecyl glycidyl ether. long-chain alkyl glycidyl ethers such as methyl, hexadecyl glycidyl ether, heptadecyl glycidyl ether, octadecyl glycidyl ether, nonadecyl glycidyl ether, methyl poly(
oxyethylene) glycidyl ether, propyl poly(
oxyethylene) glycidyl ether, pentyl poly(
Alkyl poly(oxyethylene) glycidyl ether, 2-ethylhexyl poly(oxyethylene) glycidyl ether, decyl poly(oxyethylene) glycidyl ether, dodecyl poly(oxyethylene) glycidyl ether, tetradecyl poly(oxyethylene) glycidyl ether, etc. ) glycidyl ethers and alkyl poly(oxypropylene) glycidyl ethers corresponding to these alkyl poly(oxyethylene) glycidyl ethers, phenyl poly(oxyethylene) glycidyl ethers, phenyl poly(oxypropylene) glycidyl ethers, and the like.

The amount used is based on all the epoxy compounds used in the reaction.
A range of about 0 to 30 mole percent is preferred.

If the amount used is more than this range, the molecular weight of the polyester produced will decrease, making it difficult to increase the molecular weight, and as a result, AA
The polymer of m cannot be sufficiently reinforced.

In order to synthesize the polyester used in the present invention, it is necessary to introduce at least one radically polymerizable polymerization group into the produced polyester molecule, and for this purpose, the use of the second group of epoxy compounds is essential. Furthermore, in the third group, by using an epoxy compound containing a group such as + C2H40 (where n is an integer of 10 or more), the decrease in water content of the generated hydrogel is suppressed as much as possible and the elongation (rubber hardness) is improved. be able to. In particular, the use of the third group of long-chain alkyl group-containing epoxy compounds has a remarkable effect on improving strength.

The cyclic acid anhydride used in the synthesis of the grafted polyester is preferably phthalic anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or a derivative thereof. However, itaconic anhydride, citraconic anhydride, uccinic anhydride, and maleic anhydride are not preferred from the viewpoint of the polyester produced.

The reaction between the epoxy compound and the cyclic acid anhydride is carried out in the presence of a catalyst, in a solvent or in the absence of a solvent, at a reaction temperature of about 60 to 120°C, preferably about 80 to 100°C, for about 3 to several hundred hours.
Preferably it is carried out for 5 to 300 hours.

As a catalyst used for such a reaction, for example, the formula: N-R
Basic catalysts such as tertiary amines represented by e (wherein Re, R9 and R10 are the same or different and are an alkyl group having 1 to 6 carbon atoms, a benzyl group or pyridine); Examples include basic salts of benzoic acid, lithium bromide, Ag(alkoxy)3, quaternary ammonium salts, and quaternary phosphonium salts. Specific examples of basic catalysts include dimethylbenzylamine and dimethylaminopyridine, and specific examples of quaternary ammonium salts include trimethylpensylammonium chloride, triethylbenzylammonium chloride, and tetrabutylammonium bromide. Specific examples of quaternary phosphonium salts include tetra-n-butylphosphonium bromide.

The amount of such a catalyst to be used is preferably in the range of about 0.1 to 5 mol % based on all the cyclic acid anhydrides used in the reaction. If the amount used is more than the above range, the molecular weight of the polyester produced tends to be small, which is undesirable. If the amount is less than the above range, the reaction will not proceed efficiently, leading to a decrease in the yield of the polyester produced, which is not preferred.

When the reaction is carried out in a solvent, any solvent may be used as long as it can dissolve the epoxy compound, cyclic acid anhydride, etc. to be subjected to the reaction, and preferred examples include toluene, benzene, xylene, and 1,2-dichloroethane. However, alcohols such as methanol and ethanol cannot be used because they participate in the reaction.

In addition, in the above reaction, commonly used polymerization inhibitors,
For example, hydroquinone may be used as necessary.

The polyester thus synthesized is colorless and transparent in the state of a solution dissolved in a solvent, and has excellent transparency, and is in the form of a white powder when dried.

Molecular weight was determined by gel permeation chromatography (hereinafter referred to as G, P
, C) (Trirotor] l [type G, P
, C, Analyzer (manufactured by JASCO Corporation), Detector: 5hod
ex RI 5E-31 (manufactured by Showa Denko), column:
5hodex PAKG, P, C, (A-80H type)
(Made by Showa Denko (1@), flow rate 1.0#li!/l1li
n, column temperature: 40°C, solvent: tetrahydrofuran), it is in the range of about 1000 to 100000. The molecular weight affects the mechanical properties of the hydrogel produced, and the larger the molecular weight, the better the mechanical properties of the hydrogel produced, and is also advantageous in terms of separation and purification of the synthesized polyester itself. The preferred molecular weight range is 4,000 to 60,000.

AAm used in the present invention is represented by the general formula: OR3 (wherein R1 is ■ or CH3; R2 and R3 represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms). In the formula, if the number of carbon atoms in R2 and R3 increases, it may become difficult to obtain the desired high water content, which is not preferable.

Specific examples of the AAm include (meth)acrylamide,
tomethyl(meth)acrylamide, N-ethyl(meth)acrylamide
Examples include, but are not limited to, acrylamide, N,14-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and the like.

Among the above AAm, N and N- are stable in terms of material.
Dimethylacrylamide and the like are preferably used. These AAi+ may be used alone or in combination of two or more.

The polymer according to the present invention is made by using, in addition to the polyester and AAm, a known water-containing monomer such as tovinyl lactam, which is known to have excellent transparency and water solubility. It is of course possible to adjust the physical properties of the polymer.

Specific examples of the N-vinyllactam include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, and those in which the lactam ring is substituted with one or more lower alkyl groups having 1 to 4 carbon atoms. Examples include, but are not limited to. These N-vinyl lactams may be used alone or in combination of two or more. In addition, compounds having an N-vinyl group that are polymerizable and have hydrophilic properties, such as N-vinyl heterocyclic compounds such as N-vinylpyridine and N-vinylsuccinimide, or those mentioned above. Compounds having similar properties to N-vinyllactam, such as α-methylene N-methylpyrrolidone, may be used in conjunction with N-vinyllactam or in place of tovinyllactam. Above all, its transparency,
N-vinylpyrrolidone, which is known to have good water solubility, can be preferably used.

The proportions of the polyester, AAm, optional component N-vinyl lactam, etc. used in this polymer are as follows.

In this case, it is only necessary to prepare the material as appropriate depending on the desired physical properties of the hydrogel base material, but in order to obtain a material that satisfactorily satisfies both transparency and high water content, such as a high water content contact lens, for example, It is preferable to polymerize polyester and monomers such as AA+n and N-vinyl lactam, which are additive materials for imparting hydrophilic properties, in a weight ratio of about 3=97 to 60:401, preferably about 10:90 to 30:0. .

In this case, AAm and N-
Although vinyl lactam and the like are compatible to some extent, if AAm is used in an amount of 5 parts or more, preferably 20 parts by weight or more per 100 parts by weight of the entire mixture, the desired high water content material can be scaled. It is preferable because it can be done. The following method is preferable when a large amount of polyester is used or for easily and uniformly mixing both polyester and AAi.

That is, the desired amount of purified polyester (which may be in solid or liquid form) is mixed with a halogenated hydrocarbon, such as dichloromethane, chloroform, etc., or a volatile solvent with a low boiling point that is easy to remove after mixing the polyester with Am, such as acetone. After adding a desired amount of liquid AAm into the solution and uniformly dissolving the polyester and AAn+, the solvent is evaporated, and then a polymerization initiator is added and polymerized by heating. By the way, when a solid AAm such as acrylamide is polymerized with polyester, normal radical polymerization cannot be carried out in that state because both are solid. Therefore, in such a case, it is preferable to conduct the polymerization in a state in which both acrylamide and polyester are dissolved in a solvent such as dimethyl sulfoxide or dimethyl formamide, which are good solvents. Further, if solid AAn+ or polyester is dissolved in other liquid A+n or tovinyl lactam, normal bulk polymerization becomes possible. Further, in the case of film forming, a solvent such as dimethyl sulfoxide may be used for the purpose of lowering the viscosity of the polyester-static mixture.

When the tovinyl lactam is used in the polymer of the present invention, it is preferable that the polymerizable group of the polyester is a vinyl group or an allyl group in order to improve the polymerizability.

Further, as mentioned above, for AAm, polyester containing a methacryloyl group or an acryloyl group as a polymerizable group is preferable.

Therefore, regarding the polymerizable group of the polyester used in this polymer, when using only AAI (hereinafter referred to as a single system), it is preferable to use one having one or more of methacryloyl group and acryloyl group, and AAIIl and acryloyl groups are preferred. In the case of a mixed system of tovinyl lactam (hereinafter referred to as a mixed system),
One or more of a methacrylic group and an acryloyl group,
A mixed polyester of two types of polyester each having one or more of an allyl group and a vinyl group, or the methacryloyl group in one chain of the polyester,
One or more acryloyl groups and one allyl group or vinyl group
It is preferable to use a polyester containing two or more types of polymerizable groups.

When using the above-mentioned mixture system, a more uniform product can be obtained by changing the mixing ratio of the methacryloyl group-containing polyester or acryloyl group-containing polyester and the allyl group- or vinyl group-containing polynisder according to the mixing ratio of the seven polymers used. Polymerization progresses.

Examples of the polymerization initiator used in this polymer include 282
-Azohis(2,4-dimethylvaleroni-1-lyl),
2. Peroxides such as 2-azobis(4-methoxy-2,4-dimethylvaleronitrile), azohisisobutyronitrile, penzoyl peroxylide, t-butyl hydroperoxide, cumene hydroperoxide, etc. Initiators or redox initiators are used. The amount used is approximately o, oo for all compounds subjected to polymerization.
i to 2% by weight, preferably about 0.01 to 0.5% by weight. Although there are no particular limitations on the polymerization method, it is preferable to carry out the polymerization by increasing the temperature, and the polymerization is completed by raising the temperature for several hours to several tens of hours at each temperature in the range of about 20 to about 115 degrees Celsius. It is preferable to let

In the present invention, in order to obtain a hydrogel that is even more excellent in various properties such as mechanical properties, optical properties, and water content, two or three types of polyesters with different properties are combined within the above usage range. It is preferable to use

Next, the hydrogel base material of the present invention and the hydrogel obtained therefrom will be explained based on Examples, but the present invention is not limited thereto.

Reference Example 1 [Synthesis of polyester having a polymerizable group in the molecule used in the present invention] A 3fJ round bottom flask equipped with a Dimroth was sufficiently purged with argon, and then phthalic anhydride (manufactured by Wako Tsumugi Kogyo ■) 325. 06o (2.19 mol), cyclohexene oxide (manufactured by Tokyo Kasei Kogyo-s) 204.56!
] (2,08 mol) and allyl glycidyl ether (
Manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.) 12.53 (+ (0.11 mol)
The solvent toluene 21! li#112, catalyst tetra-n-butylphosphonium bromide (manufactured by Aldrich) 1,
49 (1) and reacted with stirring at 80°C for 8 days. After cooling, the resulting viscous liquid was dissolved in about 2.51 g of dichloromethane and then added to methanol (40 J) to form a precipitate. I let it happen. After filtration, the obtained solid was
It was dried under reduced pressure at ℃ to obtain 513.181J of white solid.

The molecular weight of the polyester thus obtained is G, P,
As measured by C, number average molecular weight Rn = 34
700, and the weight average molecular weight was &-47300.

In addition, the molecular weight measurement using G, P, and C is performed using Triroto.
r type G, P, C, analyzer (manufactured by JASCO) (detector: 5hodex RI 5E-31, column: s
ho+lex PAKG, P, C, A-80H type (manufactured by Showa Denko), solvent: tetrahydrofuran), column temperature 40°C 1 flow i11.0Illi! The measurement was performed under the following conditions: /min.

Reference Example 2 A 100 d eggplant type flask equipped with a Dimroth was sufficiently purged with argon, and then phthalic anhydride (manufactured by Wako Tsumugi Kogyo Co., Ltd.) 14.290 (0,096 mol)
, cyclohexene oxide (manufactured by Tokyo Kasei Kogyo @) 8
．． 99i11 (0,092 mol), glycidyl methacrylate (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd. (41) 0.70q (0,0
05 mol) as a solvent, 10 d of toluene as a solvent, and tetrabutylphosphonium bromide as a catalyst (manufactured by Aldrich > 0.3
30 (0,001 mol) and reacted at 80°C for 5 days with stirring. After cooling, the resulting viscous liquid was dissolved in about 150 molar dichloromethane, and then methanol was dissolved in 3 methanol. J to form a precipitate. After filtration, the obtained solid was dried under reduced pressure at 40°C to give a white solid of 23.10% (
I got l. The molecular weight of the polyester thus obtained is G
, P, C, the number average molecular weight Mn = 1
5,700, and weight average molecular weight = -21,400. Note that the measurement method was performed according to Reference Example 1.

Example 1 White powdered polyester 309 obtained in Reference Example 2
Dimethyl acrylamide (manufactured by Tokyo Kasei Kogyo ■) 12
．． After uniformly mixing and dissolving in OQ, add V-65 (azobisdimethylvaleronitrile) as a polymerization initiator.
．． The polymerization solution thus obtained was placed in a polypropylene test tube with an inner diameter of 15 mm, and the polymerization solution was heated at 30°C for 48 hours, at 40°C for 4 hours, and then at 50°C for 48 hours.
4 hours at ℃, 4 hours at 60℃, 4 hours at 70℃, 80
Polymerization was carried out by heating at 95° C. for 4 hours, 95° C. for 1 hour, and 115° C. for 2 hours to synthesize a rod.

The obtained rod material was processed into a plate shape, and the plate was immersed in distilled water to swell to obtain a hydrogel base material in the shapes of Plate 1 to 1.

This hydrogel base material had excellent transparency. The water content, visible light transmittance, and punching load were measured using the plate-shaped hydrogel base material having a thickness o of 2 mm and a diameter of 15 mm by the following methods.

(Water Content) The weights of the equilibrium water-containing film and the dry film were measured.

Equilibrium water-containing film weight - Equilibrium water-containing film weight (visible light transmittance) Using a self-recording spectrophotometer tlV-240 (manufactured by Shimadzu Corporation), the transmittance of light in the wavelength range of 780 to 380 r+m was measured.

(Puncture load) Using an Instron type compression testing machine, a pressure needle with a diameter of 1716 inches (approximately 1.5911111 mm) was applied to the center of a film (approximately 0.2 mm thick) in a water-containing state. The load was measured.

Examples 2 to 13 A liquid mixture prepared using the components and amounts shown in Table 1 was subjected to a polymerization reaction in the same manner as in Example 1 to obtain a Hi-28-drogel base material. The water content, visible light transmittance, and thrust load of the obtained hydrogel base material were measured in the same manner as in Example 1.

Comparative Examples 1 to 3 Water content and visible light were measured in the same manner as in Example 1 for three types of commercially available high water content soft contact lenses that are mainly composed of tovinylpyrrolidone, a highly water content monomer that has been used conventionally. Transmittance and punch-out load were measured. The results are shown in Table 2.

[Left below] From the results shown in Table 2, the hydrogel base material of the present invention is transparent, has the same or higher water content, and is also stronger than conventional high water content soft contact lenses. It turns out that it is excellent.

The hydrogel base material of the present invention can be used for various medical materials due to its effectiveness, but it is especially useful because it has good cross-linking polymerizability, excellent transparency, and extremely little elution of AAm polymers. It can be suitably used for high water content contact lenses.

When the hydrogel base material of the present invention is used in a highly water-containing contact lens, conventional polymerization techniques and molding techniques may be used. That is, by cutting and polishing the obtained hydrogel base material, it may be made into a molded product in the shape of a contact lens, and the mixed solution of the polyester and AAm may be molded in a mold having a shape corresponding to a predetermined contact lens. It may also be cast-polymerized to form a molded product.

[Effects of the Invention] The hydrogel obtained by hydrating the hydrogel base material of the present invention has excellent transparency and a high water content. In particular, the present invention overcomes the drawback that strength decreases when the water content is increased as seen in conventional examples, and it is possible to provide a hydrogel base material with a high water content and excellent transparency and strength. It has the effect of being able to do it.

−34=

Claims (1)

[Claims] 1. An optically transparent polyester having at least one radically polymerizable polymerizable group in the molecule having a molecular weight of about 1,000 to 100,000 and a general formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (Formula In, R_1 is H or CH_3; R_2 and R_
An optically transparent hydrogel base material obtained by polymerizing a (meth)acrylamide represented by (3 represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms) as an essential component.