Method for producing polymer, method for producing curable composition, method for producing cured product, and method for producing contact lens using curable composition

Abstract

To provide a method for producing a high-purity polymer (A) and a method for inexpensively producing a silicone hydrogel lens.SOLUTION: The method for producing the polymer (A) includes (step 1) a step of polymerizing a first monomer (a) having one ethylenically unsaturated group to obtain a polymer (A1), (step 2) a step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain a polymer (A2), and (step 3) a step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A). The first monomer is selected from one of a first group consisting of epoxy group-containing monomers or a second group consisting of carboxy group-containing monomers. The second monomer is selected from the other of the first group or the second group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polymer, a method for producing a curable composition containing the polymer, a method for producing a cured product obtained by curing the curable composition, and a method for producing a hydrogel contact lens using the curable composition. [Background technology]

[0002] Because there are no blood vessels in the eye, the oxygen needed to maintain healthy eye cells cannot be supplied via the blood but is instead supplied directly from the atmosphere via the cornea. Wearing contact lenses prevents oxygen from reaching the cornea, and prolonged contact lens wear can cause corneal oxygen deficiency, leading to eye diseases such as hyperemia, corneal edema, and vascular infiltration. Therefore, oxygen permeability, one of the physical properties of contact lenses, is an important property that affects the amount of oxygen supplied to eye cells.

[0003] Contact lenses are broadly divided into hard contact lenses (HCL) and soft contact lenses (SCL). HCL has excellent optical properties and oxygen permeability, but the hardness of the material makes it prone to causing a foreign body sensation when worn. SCL has excellent wearing comfort, but the material's low oxygen permeability makes it a drawback.

[0004] In recent years, silicone hydrogel contact lenses (SHGCLs), which combine the high oxygen permeability of HCLs with the excellent wearing comfort of SCLs, have been developed and are becoming widely used.

[0005] However, the production cost of SHGCL is significantly higher than that of SCL that does not contain a silicon-containing monomer because the production of SHGCL requires the use of large amounts of organic solvents such as isopropanol or methyl ethyl ketone (several to several hundred times the dry weight of the lens) to remove unreacted silicon-containing monomer from the cured product after curing. In addition, flammable organic solvents such as isopropanol and methyl ethyl ketone (hazardous materials under the Fire Service Act of Japan) pose a high risk of fire and other disasters, and explosion-proof equipment is required as a disaster prevention measure, resulting in enormous equipment costs.

[0006] Therefore, various studies have been conducted with the aim of efficiently removing unreacted monomers and impurities in the production of contact lenses, particularly silicone hydrogel contact lenses.

[0007] For example, a method for producing a vinyl monomer containing a tris(trimethylsilyloxy)silyl group (hereinafter referred to as a TRIS group) by reacting a vinyl monomer containing a TRIS group that has a solubility or dispersibility of at least about 5% by weight in water with an actinic radiation-crosslinkable silicone-containing prepolymer made thereof has been disclosed, with the aim of improving the solubility of the vinyl monomer containing a tris(trimethylsilyloxy)silyl group in water (hereinafter referred to as a TRIS group) (see Patent Document 1).

[0008] Also disclosed is a method for producing a silicone hydrogel lens by subjecting a polymerizable composition containing a copolymerizable siloxane compound, first and second hydrophilic monomers, and first and second crosslinkable monomers as its constituent components to two-stage ultraviolet irradiation, and then extracting the unreacted components using only an aqueous solution (see Patent Document 2).

[0009] Furthermore, a method has been disclosed in which a contact lens composition containing an alcohol group-containing polysiloxane dimethacrylate is polymerized in a contact lens mold made of polyethylene vinyl alcohol resin to obtain a polymer, and then the polymer is treated under low pressure with supercritical carbon dioxide, or with supercritical carbon dioxide and an extraction aid (entrainer), thereby removing unpolymerized monomers and impurities (see Patent Document 3). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent No. 6065988 [Patent Document 2] Japanese Patent No. 6906556 [Patent Document 3] Japanese Patent No. 3640934 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the vinyl monomer containing a TRIS group obtained by the method described in Patent Document 1 does not have sufficient solubility or dispersibility in water due to the TRIS group, and it is therefore thought to be difficult to extract the unreacted vinyl monomer containing a TRIS group with water from a silicone-containing prepolymer that contains this monomer as a constituent component.

[0012] According to the method described in Patent Document 2, siloxane compounds that are poorly soluble in water are polymerized completely without any residue. However, it is unlikely that 100% of the siloxane compounds are polymerized. Furthermore, raw materials for silicon-containing monomers that exist as impurities in siloxane compounds are not incorporated into the polymer network and have low solubility in water, so organic solvents must be used to remove the raw materials for silicon-containing monomers.

[0013] In Patent Document 3, when the object is subjected to treatment with a supercritical fluid under a high pressure exceeding 20 MPa, the object is less easily separable from the mold and is more likely to have minute defects on its surface. Therefore, treatment is performed under a low pressure of 6 MPa to 16 MPa. However, while treatment with a supercritical fluid under low pressure reduces the adverse effects on the object, it naturally reduces the effectiveness of removing unreacted materials and impurities. Therefore, there is room for further study on a method for effectively removing impurities and the like without reducing workability or causing defects in the object.

[0014] As such, with conventional technology, it has been difficult to effectively remove silicon-containing compounds from the polymer network of silicone hydrogel, which contains poorly water-soluble silicon-containing compounds as its constituent components, without using flammable organic solvents (hazardous materials under the Fire Service Act of Japan) and without causing adverse effects on the material being treated.

[0015] The present invention was made in light of these circumstances, and aims to provide a manufacturing method for obtaining a highly pure (low impurity content) polymer, as well as an inexpensive method for manufacturing a silicone hydrogel lens containing the polymer. [Means for solving the problem]

[0016] That is, the present invention relates to the following [1] to

[13] . In this application, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limit values ​​are included. [1] (Step 1) a step of polymerizing a first monomer (a) having an ethylenically unsaturated group to obtain a polymer (A1); (Step 2) a step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain the polymer (A2); and (Step 3) A step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A). and The first monomer is a first group consisting of epoxy group-containing monomers, or The second group consists of carboxyl-containing monomers is selected from one of the groups, the second monomer is selected from the other of the first group or the second group; Method for producing polymer (A). [2] The method for producing the polymer (A) according to the above item [1], wherein in the step 1, a silicon-containing monomer (b) having one ethylenically unsaturated group is polymerized together with the first monomer (a). [3] The method for producing the polymer (A) according to the above item [2], wherein in the step 1, an amide group-containing monomer (c) is further polymerized. [4] The method for producing the polymer (A) according to the above item [3], wherein in the (step 1), the first monomer (a), the silicon-containing monomer (b), and the amide group-containing monomer (c) are polymerized with an alkyl group-containing monomer (d) having one ethylenically unsaturated group and having 1 to 18 carbon atoms. [5] The method for producing the polymer (A) according to any one of the above items [1] to [4], wherein carbon dioxide alone is used as the subcritical or supercritical fluid. [6] The method for producing the polymer (A) according to any one of the above items [1] to [4], wherein a mixture of carbon dioxide and an entrainer is used as the subcritical or supercritical fluid. [7] The method for producing the polymer (A) according to the above item [6], wherein the mixture of carbon dioxide and an entrainer comprises 80.0 to 99.9% by weight of carbon dioxide and 0.1 to 20.0% by weight of an entrainer. [8] The method for producing the polymer (A) according to the above item [6] or [7], wherein the entrainer is one or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol, and 1,4-dioxane. [9] A method for producing the polymer (A) according to any one of the above items [1] to [8], wherein the polymer (A) has a weight average molecular weight of 5,000 to 300,000.

[10] A method for producing a curable composition, comprising the polymer (A) according to any one of the above items [1] to [9], a hydrophilic monomer (B), and a radical polymerization initiator (C).

[11] A method for producing a cured product obtained from the curable composition according to the above item

[10] .

[12] A method for producing the curable composition according to the above item

[10] , which is used for a contact lens.

[13] A method for producing a silicone hydrogel contact lens using the curable composition for contact lenses according to the preceding item

[12] . [Effects of the Invention]

[0017] According to the manufacturing method of the present invention, a highly pure polymer and a silicone hydrogel contact lens containing the polymer can be obtained. Furthermore, the cured product of the curable composition comprising a high-purity polymer, a hydrophilic monomer, and a polymerization initiator, or the silicone hydrogel lens obtained by the method of the present invention, can be easily cleaned, and can be produced inexpensively. Furthermore, the poorly water-soluble silicon-containing compounds present in the hydrophilic polymer network can be removed without using flammable organic solvents (hazardous materials under the Fire Service Act of Japan), thereby improving the safety and efficiency of the work. Furthermore, since the method of the present invention uses the polymer as a constituent component of a silicone hydrogel contact lens, it is expected that the process of extracting impurities after contact lens formation will be easier, thereby enabling a reduction in manufacturing costs. DETAILED DESCRIPTION OF THE INVENTION

[0018] In this specification, "(meth)acrylic" means "acrylic" and / or "methacrylic," and "(meth)acrylate" means "acrylate" and / or "methacrylate." Furthermore, in this specification, "%" and "parts" are all expressed by weight unless otherwise specified.

[0019] The method for producing the polymer (A) of the present invention includes the following (Step 1) to (Step 3). (Step 1) A step of polymerizing a first monomer (a) having an ethylenically unsaturated group to obtain a polymer (A1). (Step 2) A step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain the polymer (A2). (Step 3) A step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A).

[0020] The first monomer is selected from one of the following first or second groups, and the second monomer is selected from the other of the first or second groups. Group 1: Epoxy group-containing monomers Second group: Carboxy group-containing monomers Each component in the first and second groups will be described below.

[0021] Group 1: Epoxy group-containing monomers The epoxy group-containing monomer is an epoxy group-containing monomer having one ethylenically unsaturated group and not containing silicon. The ethylenically unsaturated group in the present invention is a curable substituent, and examples thereof include a styryl group, a vinyl group, an allyl group, a maleimide group, a (meth)acryloyl group, and a (meth)acrylamide group. Examples of epoxy group-containing monomers include glycidyl acrylate, glycidyl methacrylate (trade name: GMA, manufactured by Mitsubishi Chemical Corporation), 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate (trade name: Cyclomer M-100, manufactured by Daicel Corporation), β-methylglycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether (trade name: 4HBAGE, manufactured by Mitsubishi Chemical Corporation), 1,2-epoxy-4-vinylcyclohexane (trade name: CELLOXIDE 2000, manufactured by Daicel Corporation), allyl glycidyl ether, allylphenyl glycidyl ether, and Epocalic VNBB-ME. From the viewpoint of reactivity with carboxy groups, 3,4-epoxycyclohexylmethyl acrylate and 3,4-epoxycyclohexylmethyl methacrylate are preferred.

[0022] Second group: Carboxy group-containing monomers The carboxyl group-containing monomer is a carboxyl group-containing monomer having one ethylenically unsaturated group and not having silicon. The ethylenically unsaturated group in the present invention is a curable substituent, and examples thereof include a styryl group, a vinyl group, an allyl group, a maleimide group, a (meth)acryloyl group, and a (meth)acrylamide group. Examples of carboxy group-containing monomers include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, crotonic acid, itaconic acid, maleimidocaproic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid.

[0023] When an epoxy group-containing monomer is used as the first monomer (a) and a carboxy group-containing monomer is used as the second monomer, the polymer (A1) obtained in step 1 can be reacted with the carboxy group-containing monomer in step 2 to obtain the polymer (A2). Specifically, the reaction is carried out by adding a carboxyl group-containing monomer to the epoxy groups of the polymer (A1), and the reaction temperature is preferably 80 to 120° C. The carboxyl group-containing monomer is mixed and reacted so that the amount of carboxyl groups per equivalent of the epoxy groups of the polymer (A1) is preferably 1.0 to 2.0 equivalents, more preferably 1.05 to 1.5 equivalents.

[0024] On the other hand, when a carboxyl group-containing monomer is used as the first monomer (a) and an epoxy group-containing monomer is used as the second monomer, the polymer (A1) obtained in step 1 can be reacted with the epoxy group-containing monomer in step 2 to obtain the polymer (A2). Specifically, the reaction is carried out by adding an epoxy group-containing monomer to the carboxy group of the polymer (A1), and the reaction temperature is preferably 80 to 120° C. The epoxy group-containing monomer is mixed and reacted so that the epoxy group is preferably 0.4 to 1.0 equivalent, more preferably 0.5 to 0.98 equivalent, per equivalent of the carboxy group of the polymer (A1).

[0025] To promote the addition reaction between the epoxy group and the carboxy group in step 2, it is preferable to use a catalyst such as triphenylphosphine, 2,4,6-tris(dimethylaminomethyl)phenol, triethanolamine, tetraethylammonium chloride, or trimethylglycine. Furthermore, to prevent polymerization during the reaction, a polymerization inhibitor such as paramethoxyphenol, methylhydroquinone, dibutylhydroxytoluene, 1,6-hexanediol-bis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, or pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] may be used. ], 3,9-bis-[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], and the like can also be used.

[0026] The content of the first monomer (a) (hereinafter also referred to as "component (a)") in the polymer (A1) is not particularly limited, but is, for example, 0.01 to 100 wt % of the total weight of all comonomer components, preferably 0.1 to 30 parts by weight, more preferably 0.1 to 10 wt %, and even more preferably 0.2 to 5 wt %. Here, "total comonomer components" refers to all comonomer components that are the raw materials for the polymer (A1). That is, it includes component (a), components (b) and (c) described below, and does not include polymerization initiators, etc. If the amount of component (a) is less than 0.01 wt %, the reactivity will be poor. Note that component (a) can be used alone or in a mixture of two or more types in any ratio.

[0027] In step 1, polymer (A1) may be obtained by polymerizing a silicon-containing monomer (b) having one ethylenically unsaturated group (hereinafter also referred to as "component (b)") together with component (a). Component (b) is a component that contributes to the flexibility of polymer (A).

[0028] Component (b) is a silicon-containing monomer having one ethylenically unsaturated group. Component (b) is not particularly limited, but examples thereof include α-(meth)acryloxy-ω-butylpolydimethylsiloxane, (meth)acryloxypropyltris(trimethylsiloxy)silane, (meth)acrylamide silicone, (meth)acryloxyethylcarbamoyloxysilicone, and silicone (meth)acrylate represented by the following formula (1). The silicone (meth)acrylate represented by the following formula (1) is commercially available as FM-0711 (manufactured by JNC Corporation, molecular weight 1,000). Component (b) can be used alone or in combination of two or more in any ratio.

[0029] [ka]

[0030] The content of component (b) in polymer (A1) is not particularly limited, but is, for example, 20 to 90 wt %, preferably 30 to 80 wt %, and more preferably 40 to 70 wt %, based on the total weight of all comonomer components. If the blending amount is less than 20 wt %, the oxygen permeability and flexibility of the resulting cured product will be reduced. On the other hand, if the blending amount is more than 90 wt %, the surface lubricity of the cured product will be poor.

[0031] In step 1, polymer (A1) may be obtained by polymerizing an amide group-containing monomer (c) (hereinafter also referred to as "component (c)") having one ethylenically unsaturated group together with components (a) and (b). Component (c) is a monomer that does not have a hydroxyl group or silicon, has an amide group, and is soluble in water at any ratio. Component (c) is a component that contributes to improving the hydrophilicity of polymer (A).

[0032] Examples of component (c) include, but are not limited to, acryloylmorpholine, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-vinylpyrrolidone, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinyl-N-ethylformamide, and N-vinylformamide. In the production process of a curable composition containing polymer (A), the compatibility between polymer (A) and hydrophilic monomer (B) is improved, which can contribute to improving the transparency of the cured product. Therefore, component (c) is preferably N,N-dimethylacrylamide, N,N-diethylacrylamide, or N-vinylpyrrolidone.

[0033] The content of component (c) in polymer (A1) is not particularly limited, but is, for example, 1 to 50 wt %, preferably 3 to 40 wt %, and more preferably 5 to 30 wt %, based on the total weight of all comonomer components. If the blending amount is less than 1 wt %, the compatibility with the hydrophilic monomer used in the curable composition will be poor, causing the curable composition to become cloudy. If the blending amount is more than 50 wt %, the viscosity of the polymer will increase, making it difficult to work with. Note that component (c) can be used alone or in a mixture of two or more types in any ratio.

[0034] In step 1, polymer (A1) may be obtained by polymerizing an alkyl group-containing monomer (d) (hereinafter also referred to as "component (d)") having one ethylenically unsaturated group and having 1 to 18 carbon atoms together with components (a) to (c). Component (d) does not contain a hydroxyl group, an amide group, or silicon. Component (d) contributes to the compatibility of component (b) and component (c).

[0035] Examples of the component (d) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, n-butoxyethyl (meth)acrylate, n-butoxydiethylene glycol (meth)acrylate, pentyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, and hexyl (meth)acrylate. acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, 3-methyltridecyl (meth)acrylate, 6-methyl Tridecyl (meth)acrylate, 7-methyltridecyl (meth)acrylate, 2,1,1-dimethyldodecyl (meth)acrylate, 2,7-dimethyl-4,5-diethyloctyl (meth)acrylate, pentadecyl (meth)acrylate, stearyl (meth)acrylate, i-stearyl (meth)acrylate, allyl (meth)acrylate, tricyclodecane (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate Examples of the alkyl (meth)acrylate include linear, branched, or cyclic alkyl (meth)acrylates such as dicyclopentadieneoxyethyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and 1-adamantyl (meth)acrylate. From the viewpoint of flexibility of the cured product, however, n-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate are preferred.

[0036] It is also preferable to use an alkyl group-containing monomer (d-1) (hereinafter also referred to as "component (d-1)") having one ethylenically unsaturated group and a urethane bond and having 1 to 18 carbon atoms as component (d). Component (d-1) does not contain a hydroxyl group, an amide group, or silicon. Component (d-1) contributes to the compatibility of component (b) and component (c) and also has the effect of improving the strength of the cured product.

[0037] The method for obtaining component (d-1) is not particularly limited, and examples thereof include a method of reacting an alcohol compound (I) having 1 to 18 carbon atoms (hereinafter also simply referred to as "component (I)") with an isocyanate compound (II) having one (meth)acrylate group (hereinafter also simply referred to as "component (II)"), or a method of reacting an isocyanate compound (III) having 1 to 18 carbon atoms (hereinafter also simply referred to as "component (III)") with a (meth)acrylate compound (IV) having one hydroxyl group (hereinafter also simply referred to as "component (IV)").

[0038] When reacting component (I) with component (II), the target component (d-1) can be obtained by mixing component (II) with component (I) so that the amount of isocyanate groups per equivalent of hydroxyl groups in component (I) is 1.0 to 1.2 equivalents, preferably 1.05 to 1.1 equivalents, and reacting at a reaction temperature of 70 to 90°C. When reacting component (III) with component (IV), the target component (d-1) can be obtained by mixing component (III) with component (IV) so that the amount of hydroxyl groups per equivalent of isocyanate is 1.0 to 1.2 equivalents, preferably 1.05 to 1.1 equivalents, and reacting at a reaction temperature of 70 to 90°C.

[0039] Examples of component (I) include methyl alcohol, ethyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, tridecanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.

[0040] Examples of component (II) include 2-isocyanatoethyl methacrylate (Karenz (registered trademark) MOI manufactured by Resonac Corporation), 2-isocyanatoethyl acrylate (Karenz (registered trademark) AOI manufactured by Resonac Corporation), and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate (Karenz (registered trademark) MOI-EG manufactured by Resonac Corporation).

[0041] Examples of component (III) include methyl isocyanate, ethyl isocyanate, butyl isocyanate, hexyl isocyanate, heptyl isocyanate, octyl isocyanate, nonyl isocyanate, decyl isocyanate, dodecyl isocyanate, and octadecyl isocyanate (Millionate O, manufactured by Hodogaya Chemical Co., Ltd.).

[0042] Examples of component (IV) include hydroxy C2-C4 alkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, dimethylolcyclohexyl mono(meth)acrylate, hydroxycaprolactone (meth)acrylate, hydroxyl group-terminated polyalkylene glycol (meth)acrylate, and glycerin mono(meth)acrylate.

[0043] Component (d-1) is commercially available as 2-[[(butylamino)carbonyl]oxy]ethyl acrylate (manufactured by Sigma-Aldrich) represented by the following formula (2).

[0044] [ka]

[0045] The content of component (d) in polymer (A1) is not particularly limited, but is, for example, 1 to 50 wt %, preferably 3 to 40 wt %, and more preferably 5 to 30 wt %, based on the total weight of all comonomer components. If the blending amount is less than 1 wt %, the effect of improving the compatibility between components (b) and (c) cannot be obtained. If the blending amount is more than 50 wt %, a cured product with high strength cannot be obtained.

[0046] Materials other than components (a) to (d) may be added arbitrarily to improve the performance of polymer (A). Examples of materials other than components (a) to (d) are listed below, but are not limited to these.

[0047] To impart an ultraviolet shielding function to the polymer (A), a monomer that absorbs ultraviolet light can be used. Examples of the monomer that absorbs ultraviolet light include 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 2-hydroxy-4-(meth)acryloyloxybenzophenone, 2-hydroxy-4-(meth)acryloyloxy-5-t-butylbenzophenone, 2-(2'-hydroxy-5'-(meth)acryloyloxyethylphenyl)-5-chloro-2H-benzotriazole, and 2-hydroxy-4-methacryloyloxymethylphenyl benzoate.

[0048] In order to make the polymer (A) have antifouling properties against components such as proteins and lipids in tear fluid when cured, a monomer having a fluoroalkyl group can be used. Examples of the monomer having a fluoroalkyl group include trifluoroethyl (meth)acrylate, tetrafluoroethyl (meth)acrylate, trifluoropropyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, pentafluoropropyl (meth)acrylate, hexafluorobutyl (meth)acrylate, hexafluoroisopropyl (meth)acrylate, heptafluorobutyl (meth)acrylate, octafluoropentyl (meth)acrylate, nonafluoropentyl (meth)acrylate, dodecafluoropentyl (meth)acrylate, dodecafluoroheptyl (meth)acrylate, dodecafluorooctyl (meth)acrylate, and tridecafluoroheptyl (meth)acrylate. Trifluoroethyl (meth)acrylate, tetrafluoroethyl (meth)acrylate, hexafluoroisopropyl (meth)acrylate, octafluoropentyl (meth)acrylate, and dodecafluorooctyl (meth)acrylate are preferably used, and trifluoroethyl (meth)acrylate is most preferred.

[0049] To improve the storage stability of the polymer (A), a monomer having a polymerization inhibitor effect can be used. Examples of the monomer having a polymerization inhibitor effect include 4-hydroxyphenyl methacrylate (trade name: PQMA, manufactured by Showa Denko Materials Co., Ltd.), 4-hydroxyphenyl acrylamide (trade name: HMAd, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 4-allyl-2,6-di-t-butylphenol (trade name: TRIAM-100, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (trade name: Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.), and 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate (trade name: Sumilizer GM, manufactured by Sumitomo Chemical Co., Ltd.).

[0050] To reduce the viscosity of the polymer (A) and improve its workability, a monomer having a viscosity-reducing effect can be used. Examples of the monomer having a viscosity-reducing effect include methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, ethyl carbitol acrylate, and methoxypolyethylene glycol mono(meth)acrylate.

[0051] The polymer (A1) can be obtained by a conventionally known method such as solution polymerization, bulk polymerization, suspension polymerization, etc. For example, in the case of solution polymerization, the polymer can be obtained by adding dropwise a monomer solution prepared by mixing a comonomer in a predetermined ratio in an organic solvent and a polymerization initiator under a nitrogen gas flow at a reaction temperature of 80 to 150°C to cause a polymerization reaction.

[0052] Examples of the polymerization initiator include a cationic polymerization initiator, an anionic polymerization initiator, and a radical polymerization initiator, and a radical polymerization initiator is preferred.

[0053] Examples of the radical polymerization initiator include various azo compounds or peroxides, such as thermal radical polymerization initiators. Specific examples include 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisbutyrate, 2,2'-azobis(2,4,4-trimethylpentane)diisobutylyl peroxide, di(3,5,5-trimethylhexanoyl)peroxide, and dilauroyl peroxide. Side, distearoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(3-methoxybutyl) peroxydicarbonate, cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl Peroxyneodecanoate, tert-hexylperoxyneodecanoate, tert-butylperoxyneodecanoate, tert-hexylperoxypivalate, tert-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-hexanoyl)peroxyhexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert- Butyl peroxyisobutyrate, tert-hexylperoxyisopropyl carbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, tert-butylperoxyisopropyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-hexylperoxybenzoate, 2,Examples of the radical polymerization initiator include 5-dimethyl-2,5-di(benzoylperoxy)hexane, tertiary butylperoxyacetic acid, and tertiary butylperoxybenzoate. One or more radical polymerization initiators can be used in any combination.

[0054] Examples of cationic polymerization initiators include inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as CF3COOH and CCl3COOH, and super acids such as CF3SO3H and HClO4.

[0055] Examples of the anionic polymerization initiator include butyllithium, Na-naphthalene complex, alkali metal, alkyllithium compound, sodium amide, Grignard reagent, and lithium alkoxide.

[0056] The amount of the polymerization initiator is not particularly limited, but is, for example, 0.01 to 10.0 wt %, preferably 0.05 to 9.0 wt %, and more preferably 0.1 to 8.0 wt %, based on the total weight of the comonomers. If the amount of the polymerization initiator is less than 0.01 wt %, the molecular weight of the polymer (A1) will be high, making it difficult to apply the curable composition. If the amount of the polymerization initiator is 10.0 wt % or more, the molecular weight of the polymer (A1) will be low, making it difficult to obtain a cured product with appropriate strength.

[0057] Examples of organic solvents used in the polymerization reaction include aromatics such as toluene and xylene, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and esters such as ethyl acetate, n-butyl acetate and propyl acetate, which may be used alone or in combination. Toluene is preferred because it has good solubility for the polymer (A1).

[0058] Next, step 3 will be described.

[0059] The polymer (A) of the present invention is obtained by purifying the polymer (A2) by using a subcritical or supercritical fluid to remove impurities such as the solvent, unpolymerized monomer, monomer raw material, polymerization initiator, and decomposition products of the polymerization initiator from the polymer (A2).

[0060] The purification method involves contacting the polymer before purification with a subcritical or supercritical fluid in a pressure vessel and controlling the pressure and temperature inside the pressure vessel so that the subcritical or supercritical fluid extracts impurities from the polymer. Specifically, the pressure and temperature inside the pressure vessel are controlled so that the polymer becomes insoluble in the subcritical or supercritical fluid and the subcritical or supercritical fluid dissolves the impurities. Next, the subcritical or supercritical fluid with the dissolved impurities is discharged from the pressure vessel, and the purified polymer remaining in the pressure vessel is recovered. The impurities are separated from the subcritical or supercritical fluid by reducing the pressure of the subcritical or supercritical fluid discharged from the pressure vessel.

[0061] The subcritical or supercritical fluid used in the present invention is not particularly limited, and examples thereof include carbon dioxide, nitrous oxide, sulfur hexafluoride, xenon, trifluoromethane, and monofluoromethane. Carbon dioxide is preferred because it does not remain in the polymer (A) after purification and is highly safe and easy to handle.

[0062] In addition, an extraction aid (hereinafter referred to as an entrainer) can be used together with the subcritical or supercritical fluid to adjust the polarity and improve the removal efficiency of the target substance. Examples of entrainers include water, methanol, ethanol, 1-propanol, 2-propanol, 1-hexanol, 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, and acetonitrile. However, considering ease of handling, methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol, and 1,4-dioxane are preferred, and one or more of them can be mixed in any ratio and used.

[0063] When carbon dioxide is selected as the subcritical or supercritical fluid, the ratio of carbon dioxide to entrainer is not particularly limited, but is preferably 80 to 99.9% by weight of carbon dioxide and 0.1 to 20% by weight of entrainer, more preferably 78 to 99.8% by weight of carbon dioxide and 0.2 to 22% by weight of entrainer, and particularly preferably 75 to 99.8% by weight of carbon dioxide and 0.2 to 25% by weight of entrainer. If the carbon dioxide content is less than 75% by weight, not only impurities but also the polymer (A2) will be removed, resulting in a poor yield.

[0064] Subcritical or supercritical fluids are used at various temperatures and pressures depending on the properties of the fluid, but when carbon dioxide is used, subcritical fluids are used at temperatures of 16°C to 31°C and pressures of at least 4.9 MPa, and supercritical fluids are used at temperatures of 31°C to 120°C and pressures of at least 7.4 MPa, preferably 10 MPa or more, more preferably 20 MPa or more, and particularly preferably 25 MPa or more. The fluid to be contacted may be in either a subcritical state or a supercritical state, or treatment may be performed with a fluid in both states.

[0065] The polymer (A) of the present invention preferably has a weight average molecular weight (Mw) of 5,000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 50,000 to 200,000. In the present invention, the weight average molecular weight (Mw) is measured by the GPC (gel permeation chromatography) method described in the examples below.

[0066] [Curable composition] The curable composition of the present invention contains a polymer (A) (hereinafter also referred to as "component (A)"), a hydrophilic monomer (B) (hereinafter also referred to as "component (B)"), and a radical polymerization initiator (C) (hereinafter also referred to as "component (C)").

[0067] In the curable composition of the present invention, component (A) can be used alone or in a mixture of two or more types in any ratio. The content of component (A) is preferably 30 to 99 wt % of the total amount of the curable composition of the present invention, more preferably 50 to 99 wt %, even more preferably 60 to 95 wt %, particularly preferably 70 to 90 wt %, and most preferably 75 to 90 wt %. If it is less than 30 wt %, a cured product with high oxygen permeability cannot be obtained. If it is more than 99 wt %, the viscosity of the curable composition becomes too high, making it difficult to work with.

[0068] The hydrophilic monomer (B) is not particularly limited, and examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, butoxyethylene glycol (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, acryloylmorpholine, hydroxyethyl (meth)acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-vinylpyrrolidone, acrylic acid, methacrylic acid, polyethylene glycol mono(meth)acrylate, methoxyethyl (meth)acrylate, ethyl carbitol acrylate, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinyl-N-ethylformamide, N-vinylformamide, and N-(4-hydroxyphenyl)maleimide, but are not limited thereto. N,N-dimethylacrylamide, N,N-diethylacrylamide, N-vinylpyrrolidone, and 2-hydroxyethyl methacrylate are preferred.

[0069] The hydrophilic monomer (B) may be any monomer that dissolves in water in any proportion, and may be the same as or different from the amide group-containing monomer (c) having one ethylenically unsaturated group.

[0070] In the curable composition of the present invention, component (B) can be used alone or in a mixture of two or more types in any ratio. The content of component (B) is preferably 1 to 70 wt % of the total amount of the curable composition of the present invention, more preferably 1 to 50 wt %, even more preferably 5 to 40 wt %, particularly preferably 10 to 30 wt %, and most preferably 10 to 25 wt %. If it is less than 1 wt %, the viscosity of the curable composition becomes too high, making it difficult to work with. If it is more than 70 wt %, a cured product with high oxygen permeability cannot be obtained.

[0071] The radical polymerization initiator (C) used in the curable composition of the present invention may be a thermal radical polymerization initiator or a photoradical polymerization initiator.

[0072] The thermal radical polymerization initiator is not particularly limited, and examples thereof include various azo compounds or peroxides. Specific examples thereof include 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisbutyrate, 2,2'-azobis(2,4,4-trimethylpentane)diisobutylyl peroxide, di(3,5,5-trimethylhexanoyl)peroxide, and dilauroyl peroxide. Distearoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(3-methoxybutyl) peroxydicarbonate, cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl peroxy Cineodecanoate, tert-hexylperoxyneodecanoate, tert-butylperoxyneodecanoate, tert-hexylperoxypivalate, tert-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-hexanoyl)peroxyhexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy peroxyisobutyrate, tert-hexylperoxyisopropyl carbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, tert-butylperoxyisopropyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-hexylperoxybenzoate, 2,5-dimethyl-2,Examples include 5-di(benzoylperoxy)hexane, tert-butylperoxyacetic acid, and tert-butylperoxybenzoate.

[0073] The photoradical polymerization initiator is not particularly limited, but examples thereof include various benzoin derivatives.Specific examples include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl]-2-methyl-propan-1-one, phenylglyoxylic acid methyl ester, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl -2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), and the like.

[0074] In the curable composition of the present invention, component (C) can be used alone or in a mixture of two or more types in any ratio. The content of component (C) is preferably 0.01 to 1.0 wt % of the total amount of the curable composition of the present invention, and more preferably 0.05 to 0.5 wt %. If it is less than 0.01 wt %, the polymerization reaction will be insufficient and a cured product with appropriate strength will not be obtained. If it is more than 1.0 wt %, the polymerization rate will be too fast, resulting in a non-uniform reaction, and a cured product with appropriate strength will not be obtained.

[0075] To improve transparency, the curable composition of the present invention may contain an alkyl group-containing monomer (D) (hereinafter also referred to as "component (D)") having one ethylenically unsaturated group and having 1 to 18 carbon atoms. Component (D) is not particularly limited, and the monomers exemplified as component (d) of polymer (A) can be used. The content of component (D) in the curable composition of the present invention is not particularly limited, but is, for example, 1.0 to 30.0 wt%, and preferably 3.0 to 18.0 wt%, of the total amount of the curable composition of the present invention. If the amount is less than 1.0 wt%, the transparency is not improved. If the amount is more than 20.0 wt%, the crosslinked structure becomes dense, and the flexibility of the cured product tends to decrease.

[0076] A crosslinkable monomer may be used in the curable composition of the present invention for the purpose of reinforcing the strength of the cured product. The crosslinkable monomer is not particularly limited as long as it is a compound having two or more (meth)acrylic groups or vinyl groups in the molecule. Specific examples of the crosslinkable monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol. Examples of crosslinkable monomers include, but are not limited to, (meth)acrylate crosslinkable monomers such as hexa(meth)acrylate; vinyl crosslinkable monomers such as allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl succinate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, diethylene glycol bisallyl carbonate, triallyl phosphate, triallyl trimellitate, diallyl ether, N,N-diallyl melamine, and divinylbenzene; and α,ω-methacryloxypropyl polydimethylsiloxane. These crosslinkable monomers can be used alone or in combination of two or more.

[0077] The content of the crosslinkable monomer in the curable composition of the present invention is not particularly limited, but for example, the content of the crosslinkable monomer in the total amount of the curable composition of the present invention is 0.1 to 5.0 wt%, preferably 0.3 to 3.0 wt%. If the content is less than 0.1 wt%, the cured product strength is not reinforced. If the content is more than 5 wt%, the crosslinked structure becomes dense, and the flexibility of the cured product tends to decrease.

[0078] [Silicone hydrogel contact lenses] The silicone hydrogel contact lens of the present invention can be obtained by polymerizing the curable composition of the present invention. As a method for producing the silicone hydrogel contact lens of the present invention, known methods can be used, such as polymerizing the curable composition of the present invention using a mold in the shape of a contact lens, or polymerizing the curable composition of the present invention in a tubular container and then cutting and polishing the cured product into the shape of a lens. [Example]

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" in the text are by weight.

[0080] [Example 1] (Process 1) A flask equipped with a stirrer, a dropping funnel, a condenser, and a thermometer was charged with 47.3 g of toluene, and the temperature was raised to 95°C under a nitrogen stream. Then, 3.13 g of 3,4-epoxycyclohexylmethyl methacrylate (trade name: Cyclomer M-100, manufactured by Daicel Corporation), 43.6 g of silicone methacrylate (FM-0711, manufactured by JNC Corporation, molecular weight 1,000), 5.20 g of N,N-dimethylacrylamide, 10.4 g of n-butyl acrylate, and ethyl carbitol acrylate were added. A mixed solution of 15.6 g of 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 20.4 g of toluene, and 0.41 g of dimethyl 2,2'-azobisbutyrate (trade name: V-601, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in a dropping funnel and added dropwise at a constant rate over 2 hours, followed by aging at the same temperature for 3 hours. (Process 2) Next, 1.49 g of triphenylphosphine as a reaction catalyst and 0.41 g of dibutylhydroxytoluene as a polymerization inhibitor were added, followed by 1.65 g of methacrylic acid, and the reaction was carried out at 95°C for 10 hours to obtain polymer (P-1) before purification. The epoxy equivalent was measured to be 21,000 g / eq, confirming that the epoxy groups had reacted sufficiently. [Example 2] (Process 1) A flask equipped with a stirrer, a dropping funnel, a condenser, and a thermometer was charged with 47.3 g of toluene, and the temperature was raised to 95°C under a nitrogen stream. 5.50 g of methacrylic acid, 43.6 g of silicone methacrylate (FM-0711, manufactured by JNC Corporation, molecular weight 1,000), 5.20 g of N,N-dimethylacrylamide, 10.4 g of n-butyl acrylate, and ethyl carbitol acrylate (trade name: Viscoat #190, manufactured by Osaka Organic Chemical Co., Ltd.) were added. A mixed solution of 15.6 g of 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 3.12 g of 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 21.0 g of toluene, and 0.42 g of dimethyl 2,2'-azobisbutyrate (trade name: V-601, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in a dropping funnel and added dropwise at a constant rate over 2 hours, and then aged at the same temperature for 3 hours. (Process 2) Next, 1.30 g of triphenylphosphine as a reaction catalyst and 0.45 g of dibutylhydroxytoluene as a polymerization inhibitor were added, followed by 3.45 g of 3,4-epoxycyclohexylmethyl methacrylate (trade name: Cyclomer M-100, manufactured by Daicel Corporation), and the mixture was reacted at 95°C for 10 hours to obtain polymer (P-2) before purification. The epoxy equivalent was measured to be 20,000 g / eq, confirming that the epoxy groups had reacted sufficiently.

[0081] [Example 3] (Step 3: Purification with supercritical carbon dioxide) 20.0 g of the unpurified polymer (P-1) obtained in Example 1 was placed in a pressure vessel with an internal volume of approximately 140 mL and sealed. A mixed fluid of 98 wt% carbon dioxide and 2 wt% 2-propanol was passed through the vessel at 70°C and a pressure of 25 MPa for 3 hours. Impurities were dissolved in the supercritical fluid of carbon dioxide and 2-propanol, and the supercritical fluid containing the dissolved impurities was then discharged from the vessel. Next, carbon dioxide was passed through the vessel at 70°C and a pressure of 25 MPa for 2 hours, and the 2-propanol was discharged from the vessel. The vessel was returned to atmospheric pressure, and the polymer (P-3) remaining in the vessel was obtained as polymer (A) of the present invention. The molecular weight of the obtained polymer (P-3) was measured, and the weight-average molecular weight was 75,000.

[0082] [Example 4] (Step 3: Purification with supercritical carbon dioxide) 20.0 g of the unpurified polymer (P-2) obtained in Example 2 was placed in a pressure vessel with an internal volume of approximately 140 mL and sealed. A mixed fluid of 98 wt% carbon dioxide and 2 wt% 2-propanol was passed through the vessel at 70°C and a pressure of 25 MPa for 3 hours. Impurities were dissolved in the supercritical fluid of carbon dioxide and 2-propanol, and the supercritical fluid containing the dissolved impurities was then discharged from the vessel. Next, carbon dioxide was passed through the vessel at 70°C and a pressure of 25 MPa for 2 hours, and the 2-propanol was discharged from the vessel. The vessel was returned to atmospheric pressure, and the polymer (P-4) remaining in the vessel was obtained as polymer (A) of the present invention. The molecular weight of the obtained polymer (P-4) was measured, and the weight-average molecular weight was 60,000.

[0083] [Comparative Example 1]: Purification by reduced pressure 20.0 g of the unpurified polymer (P-1) obtained in Example 1 was treated in a rotary evaporator at a reduced pressure of -0.01 kPa and 75°C for 3 hours to volatilize and remove impurities. The pressure inside the vessel was returned to normal pressure, and polymer (P-5) was obtained. The molecular weight of the obtained polymer (P-5) was measured and found to be 55,000 in weight average molecular weight.

[0084] [Comparative Example 2]: Purification by reduced pressure 20.0 g of the unpurified polymer (P-2) obtained in Example 2 was treated in a rotary evaporator at a reduced pressure of -0.01 kPa and 75°C for 3 hours to volatilize and remove impurities. The pressure inside the vessel was returned to normal pressure, and polymer (P-6) was obtained. The molecular weight of the obtained polymer (P-6) was measured and found to be 60,000 in weight average molecular weight.

[0085] In each of the Examples and Comparative Examples, the weight average molecular weight and the amount of impurities were measured as follows.

[0086] (Weight average molecular weight) The weight average molecular weight (Mw) was measured by GPC (gel permeation chromatography) under the following conditions. Analytical equipment: Tosoh GPC HLC-8320GPC Column: Tosoh SuperMultiporeHZ-H (two columns) Column temperature: 40℃ Flow rate: 0.35ml / min Eluent: tetrahydrofuran Detector: differential refractometer Standard sample: polystyrene

[0087] (Quantitative analysis of silicone methacrylate monomer FM-0711 and RUVA-93) The silicone methacrylate monomers FM-0711 and RUVA-93 contained in the polymer were quantified using LC-MS (liquid chromatography mass spectrometry). Calibration curves were created for the sample concentrations equivalent to 100 ppm, 500 ppm, and 1000 ppm. Analytical equipment: Thermo Fisher Scientific, Q-Exactive Column: CORTECS C18 Column temperature: 40℃ Mobile phase A: acetonitrile / THF (50 / 50) Mobile phase B: 5 mM ammonium acetate aqueous solution Detector: Photodiode array (PDA) detector 190-800 nm, electrospray ionization (ESI) ± (Mass Range 150-2250)

[0088] (Quantitative determination of toluene, monomer, initiator) The amounts of MAA, nBA, DMA, V#190, toluene, and IPA remaining in the polymer were quantified by GC-MS (gas chromatography mass spectrometry) using tridecane as an internal standard. Analytical equipment: Agilent 8890 Column: HP-INNOWAX 30m-0.25mm-0.25μm Carrier gas: He 1.2 mL / min. Oven: 40℃ (5 min.) - 10℃ / min. - 220℃ (18 min.) Inlet: split(30:1), 200℃ Detector: Hydrogen flame ionization detector (FID: Flame Ionization Detector) 200°C

[0089] (Quantitative determination of V-601 and M-100) The V-601 and M-100 remaining in the polymer were quantified by GC-MS (gas chromatography mass spectrometry) using tridecane as an internal standard. Analytical equipment: Agilent 8890 Column: HP-5MS 30m-0.25mm-0.25μm Carrier gas: He 1.2 mL / min. Oven: 80°C (2 min.) - 10°C / min. - 300°C (21 min.) Inlet: split(30:1), 200℃ Detector: Hydrogen flame ionization detector (FID: Flame Ionization Detector) 300°C

[0090] The amounts of impurities contained in the polymers (P-3) to (P-6) were measured and the results are shown in Table 1.

[0091] [Table 1]

[0092] The abbreviations for the compounds in Table 1 are as follows: FM-0711: Silicone methacrylate (manufactured by JNC) MAA: methacrylic acid nBA: n-butyl acrylate DMA: N,N-dimethylacrylamide V#190: Ethyl carbitol acrylate RUVA-93: 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benztriazole V-601: 2,2'-Azobisbutyric acid dimethyl ester M-100: 3,4-epoxycyclohexylmethyl methacrylate IPA: 2-propanol

[0093] [Preparation of Curable Composition] [Example 5] 7.2 g of polymer (P-2) as polymer (A); 0.9 g of N-vinylpyrrolidone, 0.6 g of N,N-diethylacrylamide, and 0.3 g of 4-hydroxybutyl acrylate as hydrophilic monomers (B); 0.6 g of lauryl acrylate as alkyl group-containing monomer (D) having 1 to 18 carbon atoms; and 0.01 g of 1,1'-azobis(cyclohexane-1-carbonitrile) as radical polymerization initiator (C) were mixed in a glass bottle and mixed using a planetary centrifugal mixer to obtain the curable composition of Example 5.

[0094] [Preparation of silicone hydrogel contact lenses] The curable composition obtained in Example 5 was placed in the female mold of a polypropylene contact lens mold, and the corresponding male and female molds were fitted together. The fitted contact lens mold was polymerized and cured at 105°C for 2 hours in a nitrogen atmosphere.

[0095] After polymerization was complete, the male and female molds were separated, and the female (male) mold with the cured product attached was immersed in a pure water / ethanol mixture (volume ratio 90 / 10) at 60°C for 1 hour to release the cured product from the female (male) mold. The resulting cured product was then immersed in saline for 1 hour, followed by autoclaving at 121°C for 30 minutes to obtain a silicone hydrogel contact lens.

[0096] When observed from directly above, the resulting silicone hydrogel contact lens was found to have a perfectly circular shape. Furthermore, light transmittance was measured using a spectrophotometer, revealing a transparency of 90% or more. [Industrial Applicability]

[0097] The polymer of the present invention has high purity, and after a curable composition using the polymer is cured, no silicon-containing monomer remains. This eliminates the need for washing using a large amount of organic solvent, making it possible to provide inexpensive contact lenses.

Claims

1. (Step 1) a step of polymerizing a first monomer (a) having an ethylenically unsaturated group to obtain a polymer (A1); (Step 2) a step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain the polymer (A2); and (Step 3) A step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A). and The first monomer is a first group consisting of epoxy group-containing monomers, or The second group consists of carboxyl group-containing monomers is selected from one of the second monomer is selected from the other of the first group or the second group; Method for producing polymer (A).

2. The method for producing the polymer (A) according to claim 1 , wherein in the step 1, a silicon-containing monomer (b) having one ethylenically unsaturated group is polymerized together with the first monomer (a).

3. The method for producing the polymer (A) according to claim 2 , wherein in the step 1, an amide group-containing monomer (c) is further polymerized.

4. 4. The method for producing polymer (A) according to claim 3, wherein in (Step 1), the first monomer (a), the silicon-containing monomer (b), and the amide group-containing monomer (c) are polymerized together with an alkyl group-containing monomer (d) having one ethylenically unsaturated group and having 1 to 18 carbon atoms.

5. The method for producing the polymer (A) according to any one of claims 1 to 4, wherein carbon dioxide alone is used as the subcritical or supercritical fluid.

6. The method for producing the polymer (A) according to any one of claims 1 to 4, wherein a mixture of carbon dioxide and an entrainer is used as the subcritical or supercritical fluid.

7. The method for producing polymer (A) according to claim 6, wherein the mixture of carbon dioxide and an entrainer comprises 80.0 to 99.9% by weight of carbon dioxide and 0.1 to 20.0% by weight of an entrainer.

8. The method for producing polymer (A) according to claim 6 or 7, wherein the entrainer is at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol, and 1,4-dioxane.

9. The method for producing polymer (A) according to any one of claims 1 to 8, wherein the polymer (A) has a weight average molecular weight of 5,000 to 300,000.

10. A method for producing a curable composition comprising the polymer (A) according to any one of claims 1 to 9, a hydrophilic monomer (B), and a radical polymerization initiator (C).

11. A method for producing a cured product obtained from the curable composition according to claim 10.

12. The method for producing the curable composition according to claim 10, which is used for a contact lens.

13. A method for producing a silicone hydrogel contact lens using the curable composition for contact lenses according to claim 12.

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