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

Abstract

Provided are: a method for producing a high-purity polymer (A); and a method for producing an inexpensive silicone hydrogel lens. This method for producing a polymer (A) comprises: a step (step 1) for obtaining a polymer (A1) by polymerizing a first monomer (a) having one ethylenically unsaturated group; a step (step 2) for obtaining a polymer (A2) by reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group; and a step (step 3) for obtaining a polymer (A) by purifying the polymer (A2) using a subcritical or supercritical fluid. The first monomer is selected from one of the following first group and second group: the first group comprising hydroxyl group-containing monomers, and the second group comprising an isocyanate compound of (meth) acrylic acid, an acid anhydride of (meth) acrylic acid, and a halide of (meth) acrylic acid. The second monomer is selected from the other one of the first group and the second group.

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 silicone hydrogel contact lens using the curable composition. Background Art

[0002] Because ocular tissue lacks blood vessels, the oxygen necessary to maintain healthy eye cells cannot be supplied through the bloodstream. Instead, oxygen is supplied directly from the atmosphere through the cornea. Wearing contact lenses impedes the supply of oxygen to the cornea, leading to corneal hypoxia and other eye conditions such as congestion, corneal edema, and vascular infiltration. Therefore, oxygen permeability, a physical property of contact lenses, is crucial in influencing the oxygen supply to eye cells.

[0003] Contact lenses can be broadly categorized as hard contact lenses (HCL) and soft contact lenses (SCL). HCLs offer excellent optical properties and oxygen permeability, but their harder material can cause a foreign body sensation when worn. While SCLs offer excellent wearing comfort, their material has the disadvantage of low oxygen permeability.

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

[0005] However, the manufacturing cost of SHGCL is significantly higher than that of SCL, which does not contain silicon monomers. This is because the production of SHGCL requires the use of large amounts of organic solvents such as isopropyl alcohol or methyl ethyl ketone (several to hundreds of times the dry weight of the lens) to remove unreacted silicon monomers from the cured product.

[0006] Furthermore, flammable organic solvents such as isopropyl alcohol and methyl ethyl ketone (hazardous substances under Japanese fire regulations) pose a high risk of fire and other disasters, requiring explosion-proof equipment as a preventative measure, resulting in significant equipment costs.

[0007] Therefore, various studies have been conducted to effectively remove unreacted monomers and impurities in the production of contact lenses, particularly silicone hydrogel contact lenses.

[0008] For example, a method is disclosed for improving the water solubility of a vinyl monomer containing a tris(trimethylsiloxy)silyl group (hereinafter referred to as a TRIS group) by reacting a vinyl monomer containing a TRIS group having a solubility or dispersibility in water of at least about 5% by weight with a photochemically crosslinkable silicone prepolymer composed of the vinyl monomer to produce the TRIS group-containing vinyl monomer (see Patent Document 1).

[0009] Furthermore, a method for producing silicone hydrogel contact lenses is disclosed, wherein a polymerizable composition comprising a copolymerizable siloxane compound, first and second hydrophilic monomers, and first and second crosslinkable monomers is subjected to two-step ultraviolet irradiation, and then unreacted components are extracted using only an aqueous solution (see Patent Document 2).

[0010] Another method is disclosed, in which a contact lens composition containing an alcohol group-containing polysiloxane dimethacrylate is polymerized in a contact lens forming mold made of a polyethylene-vinyl alcohol resin. After obtaining a polymer, the polymer is treated with supercritical carbon dioxide or supercritical carbon dioxide and an extraction aid (entrainer) under low pressure to remove unpolymerized monomers or impurities (see Patent Document 3).

[0011] [Prior art literature]

[0012] [Patent Document]

[0013] [Patent Document 1] Japanese Patent No. 6065988

[0014] [Patent Document 2] Japanese Patent No. 6906556

[0015] [Patent Document 3] Japanese Patent No. 3640934. Summary of the Invention

[0016] [Problems to be solved by the invention]

[0017] However, the TRIS group-containing vinyl monomer obtained by the method described in Patent Document 1 has insufficient solubility or dispersibility of the TRIS group in water. Therefore, it is considered difficult to extract the unreacted TRIS group-containing vinyl monomer from the silicone-containing prepolymer containing the monomer as a constituent component with water.

[0018] According to the method of Patent Document 2, the poorly soluble siloxane compound in water is not left behind and is completely polymerized. However, it is considered difficult to achieve 100% polymerization of the siloxane compound. In addition, the raw material compound of the silicon-containing monomer present as an impurity in the siloxane compound is not incorporated into the polymer network and has low solubility in water, necessitating the use of an organic solvent to remove the raw material compound of the silicon-containing monomer.

[0019] Patent Document 3 states that supercritical fluid treatment at high pressures exceeding 20 MPa reduces the separability of the target product from the mold and easily creates microscopic defects on the target product's surface. Therefore, treatment is performed at lower pressures of 6 to 16 MPa. However, while supercritical fluid treatment at low pressures can mitigate adverse effects on the target product, it also reduces the effectiveness of removing unreacted products or impurities. Therefore, there is room for research on effective impurity removal methods that do not compromise workability or create defects in the target product.

[0020] Thus, in conventional technology, it is difficult to effectively remove silicon-containing compounds from the polymer network of silicon hydrogel, which contains water-insoluble silicon-containing compounds as its constituent components, without using flammable organic solvents (hazardous substances under the Japanese Fire Protection Act) and without adversely affecting the target object.

[0021] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a high-purity polymer (low in impurities) and a method for inexpensively producing a silicone hydrogel lens comprising the polymer.

[0022] [Solution to the problem]

[0023] That is, the present invention relates to the following [1] to

[18] . In addition, in this application, "(numerical value 1) to (numerical value 2)" indicates that the upper and lower limits are inclusive. [1]

[0025] A method for producing a polymer (A) comprises the following steps:

[0026] (Step 1) a step of polymerizing a first monomer (a) having an ethylenically unsaturated group to obtain a polymer (A1),

[0027] (Step 2) a step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain a polymer (A2), and

[0028] (Step 3) A step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A), wherein:

[0029] The first monomer is selected from the following group 1 or group 2,

[0030] Group 1 composed of monomers containing hydroxyl groups,

[0031] The second group consisting of (meth)acrylic acid isocyanate compounds, (meth)acrylic acid anhydrides, and (meth)acrylic acid halides,

[0032] The second monomer is selected from the other of the first group or the second group. [2]

[0034] The method for producing the polymer (A) as described in the above item [1] is characterized in that, in the above (step 1), the first monomer (a) is polymerized together with a silicon-containing monomer having one ethylenically unsaturated group. [3]

[0036] The method for producing the polymer (A) as described in the above item [2] is characterized in that, in the above (step 1), an amide group-containing monomer (c) is further polymerized. [4]

[0038] The method for producing a polymer (A) as described in the above item [3], wherein in the aforementioned (step 1), the aforementioned first monomer (a), the aforementioned silicon-containing monomer (b) and the aforementioned 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]

[0040] The method for producing a polymer (A) according to any one of [1] to [4], wherein the first monomer is a hydroxyl group-containing monomer. [6]

[0042] The method for producing a polymer (A) as described in the above item [5], wherein the second monomer is an isocyanate compound of (meth)acrylic acid. [7]

[0044] The method for producing a polymer (A) as described in the above item [5], wherein the second monomer is an anhydride of (meth)acrylic acid. [8]

[0046] The method for producing a polymer (A) according to the aforementioned item [5], wherein the second monomer is a halide of (meth)acrylic acid. [9]

[0048] The method for producing a polymer (A) according to any one of [1] to [4], wherein

[0049] The first monomer is an isocyanate compound of (meth)acrylic acid,

[0050] The second monomer is a hydroxyl group-containing monomer.

[10]

[0052] The method for producing a polymer (A) according to any one of [1] to [9], wherein only carbon dioxide is used as the subcritical or supercritical fluid.

[11]

[0054] The method for producing a polymer (A) according to any one of [1] to [9], wherein carbon dioxide and an entrainer are used as the subcritical or supercritical fluid.

[12]

[0056] The method for producing a polymer (A) as described in the above item

[11] , wherein the mixture of carbon dioxide and an entrainer comprises 80.0 to 99.9 wt% of carbon dioxide and 0.1 to 20.0 wt% of an entrainer.

[13]

[0058] The method for producing a polymer (A) according to the above item

[11] or

[12] , wherein the entrainer is one or more selected from methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 1,4-dioxane.

[14]

[0060] The method for producing a polymer (A) as described in any one of the above items [1] to

[13] , wherein the weight average molecular weight of the polymer (A) is 5,000 to 300,000.

[15]

[0062] A method for producing a curable composition, wherein the curable composition comprises the polymer described in any one of the above items [1] to

[14] , a hydrophilic monomer (B), and a radical polymerization initiator (C).

[16]

[0064] A method for producing a cured product, wherein the cured product is obtained by curing the curable composition described in the above item

[15] .

[17]

[0066] The method for producing a curable composition according to the above item

[15] , wherein the curable composition is used for contact lenses.

[18]

[0068] A method for producing a silicone hydrogel contact lens, comprising using the curable composition for contact lenses described in the above item

[17] .

[0069] [Effects of the Invention]

[0070] According to the production method of the present invention, a high-purity polymer and a silicone hydrogel contact lens having the polymer in its structure can be obtained.

[0071] Furthermore, the cured product or silicone hydrogel contact lens obtained by the method of the present invention, which is composed of a curable composition comprising a high-purity polymer, a hydrophilic monomer, and a polymerization initiator, can be easily cleaned and thus manufactured inexpensively. Furthermore, the poorly water-soluble silicon-containing compounds present in the hydrophilic polymer network can be removed without the use of flammable organic solvents (hazardous substances under the Japanese Fire Services Act), thereby improving work safety and efficiency.

[0072] In addition, since the method of the present invention uses the polymer as a component of silicone hydrogel contact lenses, the process of extracting impurities after forming the contact lenses is easier, thereby potentially reducing manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 GPC chart of polymer (P-5).

[0074] Figure 2 GPC chart of polymer (P-6).

[0075] Figure 3 GPC chart of FM-0711.

[0076] Description of Reference Numerals

[0077] none. DETAILED DESCRIPTION

[0078] In this specification, "(meth)acrylate" refers to "acrylate" and / or "methacrylate," and "(meth)acrylate" refers to "acrylate" and / or "methacrylate." Furthermore, "%" and "parts" in this specification are by weight unless otherwise specified.

[0079] The method for producing the polymer (A) of the present invention comprises the following (Step 1) to (Step 3).

[0080] (Step 1) A step of polymerizing a first monomer (a) having an ethylenically unsaturated group to obtain a polymer (A1)

[0081] (Step 2) A step of reacting the polymer (A1) with a second monomer having an ethylenically unsaturated group to obtain the polymer (A2)

[0082] (Step 3) Purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A)

[0083] The first monomer may be selected from either the following Group 1 or Group 2, and the second monomer may be selected from the other of the following Group 1 or Group 2.

[0084] Group 1: Hydroxyl-containing monomers

[0085] Group 2: (Meth)acrylic acid isocyanate compounds, (meth)acrylic acid anhydrides, and (meth)acrylic acid halides

[0086] The components of Group 1 and Group 2 are described below.

[0087] Group 1: Hydroxyl-containing monomers

[0088] The hydroxyl-containing monomer is a hydroxyl-containing monomer having one ethylenically unsaturated group and does not contain silicon. The ethylenically unsaturated group in the present invention is a hardenable substituent, and examples thereof include styryl, vinyl, allyl, maleimide, (meth)acryloyl, and (meth)acrylamide.

[0089] Examples of hydroxyl-containing monomers include acrylic acid, methacrylic acid, 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, N-(4-hydroxyphenyl)maleimide, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polybutylene glycol mono(meth)acrylate, and N-(2-hydroxyethyl)acrylamide.

[0090] Group 2: (Meth)acrylic acid isocyanate compounds

[0091] The (meth)acrylic isocyanate compound refers to an acrylate or methacrylate having an isocyanate group.

[0092] Examples of the isocyanate compound of (meth)acrylic acid include 2-isocyanatoethyl methacrylate (trade name: Karenz MOI, manufactured by Resonac), 2-isocyanatoethyl acrylate (trade name: Karenz AOI, manufactured by Resonac), 2-(2-methacryloyloxyethyloxy)ethyl isocyanate (trade name: Karenz MOI-EG, manufactured by Resonac), and 1,1-(bisacryloyloxymethyl)ethyl isocyanate (trade name: Karenz BEI, manufactured by Resonac).

[0093] When a hydroxyl group-containing monomer is used as the first monomer (a) and a (meth)acrylic acid isocyanate compound is used as the second monomer, the polymer (A1) obtained in step 1 is reacted with the (meth)acrylic acid isocyanate compound in step 2 to obtain a polymer (A2).

[0094] Specifically, an isocyanate compound having a (meth)acrylate group is added to the hydroxyl groups of the polymer (A1) and reacted at a reaction temperature preferably from 70 to 100° C. The isocyanate compound having a (meth)acrylate group is preferably mixed and reacted in an amount of 1.0 to 1.2 equivalents of isocyanate groups per equivalent of hydroxyl groups in the polymer (A1), and more preferably 1.05 to 1.1 equivalents.

[0095] On the other hand, when a (meth)acrylic acid isocyanate compound is used as the first monomer (a) and a hydroxyl-containing monomer is used as the second monomer, the polymer (A1) obtained in step 1 is reacted with the hydroxyl-containing monomer in step 2 to obtain a polymer (A2).

[0096] Specifically, a hydroxyl group-containing monomer is added to the isocyanate group of the polymer (A1) and the reaction temperature is preferably 70 to 100° C. The hydroxyl group-containing monomer is preferably mixed and reacted in an amount of 1.0 to 1.2 equivalents, more preferably 1.05 to 1.1 equivalents, per 1 equivalent of isocyanate group in the polymer (A1).

[0097] In order to promote the addition reaction between the hydroxyl group and the isocyanate group in step 2, it is preferable to use a catalyst such as dibutyltin dilaurate. In addition, in order to prevent polymerization during the reaction, a polymerization inhibitor such as p-methoxyphenol, methylhydroquinone, or dibutylhydroxytoluene may be used.

[0098] Group 2: (Meth)acrylic acid anhydrides

[0099] (Meth)acrylic acid anhydride means acrylic anhydride and / or methacrylic anhydride.

[0100] When a hydroxyl group-containing monomer is used as the first monomer (a) and (meth)acrylic acid anhydride is used as the second monomer, the polymer (A1) obtained in step 1 is reacted with acrylic anhydride and / or methacrylic anhydride to obtain the polymer (A2).

[0101] Specifically, acrylic anhydride and / or methacrylic anhydride are added to the hydroxyl groups of the polymer (A1) at a reaction temperature preferably between 80 and 120°C. The acrylic anhydride and / or methacrylic anhydride are preferably mixed and reacted in an amount of 1.0 to 1.2 equivalents, more preferably 1.05 to 1.1 equivalents, per 1 equivalent of hydroxyl groups in the polymer (A1).

[0102] To promote the reaction, it is preferred 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 p-methoxyphenol, methylhydroquinone, or dibutylhydroxytoluene may be used.

[0103] Group 2: (Meth)acrylic acid halides

[0104] Specific examples of the halide of (meth)acrylic acid include (meth)acryloyl fluoride, (meth)acryloyl chloride, (meth)acryloyl bromide, and (meth)acryloyl iodide.

[0105] When a hydroxyl group-containing monomer is used as the first monomer and a (meth)acrylic acid halide is used as the second monomer, the polymer (A2) can be obtained by reacting the polymer (A1) obtained in step 1 with the (meth)acrylic acid halide.

[0106] Specifically, a dehydrohalogenation reaction is carried out between the hydroxyl groups of the polymer (A1) and the halogen groups of the (meth)acrylic acid halide. The reaction temperature is preferably 30 to 100°C. The (meth)acrylic acid halide is preferably used in an amount equivalent to the hydroxyl groups of the polymer (A1). Furthermore, during the reaction, polymerization inhibitors such as p-methoxyphenol, methylhydroquinone, and dibutylhydroxytoluene may be used to prevent polymerization.

[0107] Since the reaction between polymer (A1) and the (meth)acrylic acid halide is a dehydrohalogenation reaction, it is preferred to pre-add a tertiary amine to the reaction solution to capture the generated hydrogen halide and further promote the reaction. Examples of the tertiary amine include triethylamine, pyridine, and 1-methylimidazole. The amount of the tertiary amine used is preferably equimolar to 2 times the molar amount of the (meth)acrylic acid chloride, and more preferably equimolar to 1.5 times the molar amount.

[0108] The content of the first monomer (a) (hereinafter also referred to as "component (a)") in the polymer (A1) is not particularly limited. For example, it is 0.01 to 100% by weight relative to the total weight of the total comonomer components, preferably 0.1 to 30% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.2 to 5% by weight. Here, the total comonomer components refer to all comonomer components that become the raw materials of the polymer (A1). That is, component (a), component (b) described later, component (c), etc. do not include polymerization initiators, etc. When the amount of component (a) is less than 0.01% by weight, the reactivity will deteriorate. In addition, component (a) can be used as one or a mixture of two or more in any proportion.

[0109] In step 1, component (a) and a silicon-containing monomer (b) having one ethylenically unsaturated group (hereinafter also referred to as "component (b)") are polymerized to obtain polymer (A1). Component (b) contributes to the flexibility of polymer (A).

[0110] Component (b) is a silicon-containing monomer having one ethylenically unsaturated group. Component (b) is not particularly limited, and examples thereof include α-(meth)acryloyloxy-ω-butyl polydimethylsiloxane, (meth)acryloyloxypropyltris(trimethylsiloxy)silane, (meth)acrylamide polysiloxane, (meth)acryloyloxyethylamine formyloxy polysiloxane, and polysiloxane (meth)acrylate represented by the following formula (1). In addition, polysiloxane (meth)acrylate represented by the following formula (1) can be commercially available as FM-0711 (manufactured by JNC Co., Ltd., molecular weight 1,000). Component (b) can be used alone or as a mixture of two or more in any proportion.

[0111]

[0112] The content of component (b) in polymer (A1) is not particularly limited. For example, it is 20 to 90% by weight, preferably 30 to 80% by weight, and more preferably 40 to 70% by weight, relative to the total weight of all comonomer components. If the content is less than 20% by weight, the oxygen permeability and flexibility of the resulting cured product may be reduced. Furthermore, if the content exceeds 90% by weight, the surface lubricity of the cured product may be impaired.

[0113] In step 1, components (a) and (b) are polymerized with an amide group-containing monomer (c) having one ethylenically unsaturated group (hereinafter also referred to as "component (c)") to obtain polymer (A1). Component (c) is a monomer that does not have hydroxyl groups or silicon, but has an amide group and is soluble in water in any proportion. Component (c) contributes to improving the hydrophilicity of polymer (A).

[0114] 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 preparation of a curable composition comprising polymer (A), N,N-dimethylacrylamide, N,N-diethylacrylamide, and N-vinylpyrrolidone are preferred because they contribute to improving the compatibility between polymer (A) and the hydrophilic monomer (B) and enhancing the transparency of the cured product.

[0115] The content of component (c) in polymer (A1) is not particularly limited. For example, it is 1 to 50% by weight, preferably 3 to 40% by weight, and more preferably 5 to 30% by weight, relative to the total weight of all comonomer components. A blending amount of less than 1% by weight may impair compatibility with the hydrophilic monomer used in the curable composition, resulting in turbidity in the curable composition. A blending amount exceeding 50% by weight may increase the viscosity of the polymer and impair workability. Component (c) may be used singly or as a mixture of two or more in any proportion.

[0116] In step 1, components (a) to (c) are polymerized with an alkyl-containing monomer (d) having one ethylenically unsaturated group and having 1 to 18 carbon atoms (hereinafter also referred to as "component (d)") to obtain polymer (A1). Component (d) does not have a hydroxyl group, an amide group, or silicon. Component (d) contributes to the compatibility of components (b) and (c).

[0117] Examples of the component (d) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-butoxyethyl (meth)acrylate, n-butoxydiethylene glycol (meth)acrylate, pentyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, hexyl (meth)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-methyldecyl (meth)acrylate. Trialkyl esters, 7-methyltridecyl (meth)acrylate, 2,1,1-dimethyldodecyl (meth)acrylate, 2,7-dimethyl-4,5-diethyloctyl (meth)acrylate, pentadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, allyl (meth)acrylate, tricyclodecyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentadienyl Examples of the present invention include linear, branched, or cyclic alkyl (meth)acrylates such as alkenyloxyethyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and 1-adamantyl (meth)acrylate. However, from the viewpoint of the flexibility of the cured product, n-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate are preferred.

[0118] As component (d), it is preferred to use an alkyl-containing monomer (d-1) having one ethylenically unsaturated group and a urethane bond and having 1 to 18 carbon atoms (hereinafter also referred to as "component (d-1)"). Component (d-1) does not contain hydroxyl groups, amide groups, or silicon. Component (d-1) improves compatibility with components (b) and (c) and also has the effect of increasing the strength of the cured product.

[0119] The method for obtaining component (d-1) is not particularly limited, and includes: a method of reacting an alcohol compound (I) having 1 to 18 carbon atoms (hereinafter also referred to as "component (I)") with an isocyanate compound (II) having one (meth)acrylate group (hereinafter also referred to as "component (II)"), or a method of reacting an isocyanate compound (III) having 1 to 18 carbon atoms (hereinafter also referred to as "component (III)") with a (meth)acrylate compound (IV) having one hydroxyl group (hereinafter also referred to as "component (IV)").

[0120] When reacting component (I) with component (II), 1.0 to 1.2 equivalents of component (II) per equivalent of hydroxyl groups of component (I), preferably 1.05 to 1.1 equivalents, are mixed with component (I), and the reaction is carried out at a reaction temperature of 70 to 90°C to obtain the target component (d-1). When reacting component (III) with component (IV), 1.0 to 1.2 equivalents of component (IV) per equivalent of hydroxyl groups of component (III), preferably 1.05 to 1.1 equivalents, are mixed with component (III), and the reaction is carried out at a reaction temperature of 70 to 90°C to obtain the target component (d-1).

[0121] Examples of the component (I) include methanol, ethanol, butanol, hexanol, octanol, tridecanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.

[0122] Examples of component (II) include 2-isocyanatoethyl methacrylate (Karenz (registered trademark) MOI manufactured by Resonac Co., Ltd.), 2-isocyanatoethyl acrylate (Karenz (registered trademark) AOI manufactured by Resonac Co., Ltd.), and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate (Karenz (registered trademark) MOI-EG manufactured by Resonac Co., Ltd.).

[0123] Examples of the 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.).

[0124] Examples of component (IV) include hydroxy C2 to C4 alkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, dimethylolcyclohexyl mono(meth)acrylate, hydroxycaprolactone (meth)acrylate, hydroxyl-terminated polyalkylene glycol (meth)acrylate, and glycerol mono(meth)acrylate.

[0125] Component (d-1) can be commercially available 2-[[(butylamino)carbonyl]oxy]ethyl acrylate (manufactured by Sigma-Aldrich) represented by the following formula (2).

[0126]

[0127] The content of component (d) in polymer (A1) is not particularly limited, but may be, for example, 1 to 50% by weight, preferably 3 to 40% by weight, and more preferably 5 to 30% by weight, relative to the total weight of all comonomer components. If the content is less than 1% by weight, the effect of improving the compatibility between components (b) and (c) may not be achieved. If the content exceeds 50% by weight, a high-strength cured product may not be obtained.

[0128] Materials other than components (a) to (d) may be optionally added for the purpose of improving the performance of the polymer (A). Examples of materials other than components (a) to (d) include, but are not limited to, the following.

[0129] A monomer that absorbs ultraviolet light can be used to impart an ultraviolet shielding function to the polymer (A). Examples of the ultraviolet absorbing monomer 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-tert-butylbenzophenone, 2-(2'-hydroxy-5'-(meth)acryloyloxyethylphenyl)-5-chloro-2H-benzotriazole, and 2-hydroxy-4-methacryloyloxymethylphenylbenzoate.

[0130] A monomer having a fluoroalkyl group can be used in polymer (A) to impart an antifouling function to the cured product against components such as proteins and lipids in tear fluid. Examples of monomers 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 preferred. Most preferred is trifluoroethyl (meth)acrylate.

[0131] In order to improve the storage stability of the polymer (A), a monomer having a polymerization inhibitory effect may be used. Examples of monomers having a polymerization inhibitory 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-tert-butylphenol (trade name: TRIAM-100, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2-[1-(2-hydroxy-3,5-di-tert-amylphenyl)ethyl]-4,6-di-tert-butylphenyl acrylate (trade name: Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.), and 2,4-di-tert-amyl-6-[1-(3,5-di-tert-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate (trade name: Sumilizer GM, manufactured by Sumitomo Chemical Co., Ltd.).

[0132] Polymer (A1) can be obtained by conventionally known methods such as solution polymerization, bulk polymerization, and suspension polymerization. For example, in solution polymerization, a monomer solution containing a comonomer and a polymerization initiator mixed at a predetermined ratio is added dropwise to an organic solvent under a nitrogen stream at a reaction temperature of 80 to 150°C, and the mixture is allowed to polymerize.

[0133] Examples of the polymerization initiator include cationic polymerization initiators, anionic polymerization initiators, and radical polymerization initiators, with radical polymerization initiators being preferred.

[0134] Examples of the free radical polymerization initiator include various azo compounds or peroxides as thermal free radical polymerization initiators. Specifically, examples include 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-dimethylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobisbutyric acid dimethyl ester, 2,2'-azobis(2,4,4-trimethylpentane) diisobutyryl peroxide, and di(3,5,5-trimethylpentane). peroxydicarbonate, diisopropyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(3-methoxybutyl) peroxydicarbonate, cumene peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1- Cyclohexyl-1-methylethyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxytrimethylacetate, tert-butyl peroxytrimethylacetate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-hexanoyl)peroxyhexane, tert-hexyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, tert-hexyl Isopropyl peroxycarbonate, tert-butyl peroxymaleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxyacetic acid, tert-butyl peroxybenzoate, etc. The radical polymerization initiator may be used alone or as a mixture of two or more in any ratio.

[0135] Examples of the cationic polymerization initiator include inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as CF3COOH and CCl3COOH, and superacids such as CF3SO3H and HClO4.

[0136] Examples of the anionic polymerization initiator include butyllithium, Na-naphthalene complex, alkali metal, alkyllithium compound, sodium amide, Grignard reagent, and lithium alkoxide.

[0137] The amount of polymerization initiator added is not particularly limited. For example, it is 0.01 to 10.0% by weight, preferably 0.05 to 9.0% by weight, and more preferably 0.1 to 8.0% by weight, relative to the total weight of the comonomers. If the amount of polymerization initiator added is less than 0.01% by weight, the molecular weight of the polymer (A1) will increase, making it difficult to apply the curable composition. If the amount of polymerization initiator added exceeds 10.0% by weight, the molecular weight of the polymer (A1) will decrease, and a cured product with adequate strength may not be obtained.

[0138] Organic solvents used in the polymerization reaction include aromatic solvents 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. These solvents can be used alone or in combination. Toluene is preferred due to its good solubility in polymer (A1).

[0139] Next, step 3 will be described.

[0140] The polymer (A) of the present invention can be obtained by removing impurities such as the solvent, unpolymerized monomers, monomer raw materials, polymerization initiators, and decomposition products of the polymerization initiator from the polymer (A2) using a subcritical or supercritical fluid to purify the polymer (A2).

[0141] The purification method involves contacting the pre-purified polymer with a subcritical or supercritical fluid within a pressure vessel. The pressure and temperature within the pressure vessel are then controlled to extract impurities from the polymer. Specifically, the pressure and temperature within the pressure vessel are controlled to a level that renders the polymer insoluble in the subcritical or supercritical fluid but dissolves the impurities. The subcritical or supercritical fluid containing the impurities is then discharged from the pressure vessel, and the purified polymer remaining in the pressure vessel is recovered. By reducing the pressure of the subcritical or supercritical fluid discharged from the pressure vessel, the impurities can be separated from the subcritical or supercritical fluid.

[0142] 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, monofluoromethane, etc., but carbon dioxide is preferred because it does not remain in the purified polymer (A), is highly safe, and is easy to handle.

[0143] Furthermore, to adjust the polarity and improve the removal efficiency of the target substance, an extraction aid (hereinafter referred to as an entrainer) may be used with the subcritical or supercritical fluid. Examples of entrainers include water, methanol, ethanol, 1-propanol, 2-propanol, 1-hexanol, 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, and acetonitrile. However, considering the handling efficiency, methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol, and 1,4-dioxane are preferred. One or more of these can be used alone or in combination in any ratio.

[0144] When carbon dioxide is selected as the subcritical or supercritical fluid, the ratio of carbon dioxide to the 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 the entrainer, more preferably 78 to 99.8% by weight of carbon dioxide and 0.2 to 22% by weight of the entrainer, and particularly preferably 75 to 99.8% by weight of carbon dioxide and 0.2 to 25% by weight of the entrainer. If the carbon dioxide content is less than 75% by weight, not only impurities but also polymer (A2) may be removed, resulting in an unfavorable yield.

[0145] Subcritical or supercritical fluids can be used at various temperatures and pressures depending on the properties of the fluid. When using carbon dioxide, subcritical fluids can be used at temperatures between 16°C and 31°C and a pressure of at least 4.9 MPa, while supercritical fluids can be used at temperatures between 31°C and 120°C and a pressure of at least 7.4 MPa. Pressures of 10 MPa or higher are preferred, 20 MPa or higher is more preferred, and 25 MPa or higher is particularly preferred. The contacting fluid may be in either a subcritical or supercritical state, or may be treated with fluids in both states.

[0146] The weight average molecular weight (Mw) of the polymer (A) of the present invention is preferably 5,000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 50,000 to 200,000. The weight average molecular weight (Mw) in the present invention is measured by GPC (gel permeation chromatography) as described in the Examples below.

[0147] [Curable composition]

[0148] 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)").

[0149] In the curable composition of the present invention, component (A) may be used singly or in combination of two or more in any proportion. The content of component (A) in the total amount of the curable composition of the present invention is preferably 30 to 99% by weight, more preferably 50 to 99% by weight, even more preferably 60 to 95% by weight, particularly preferably 70 to 90% by weight, and most preferably 75 to 90% by weight. If the content is less than 30% by weight, a cured product with high oxygen permeability cannot be obtained. If the content is greater than 99% by weight, the viscosity of the curable composition increases, resulting in unfavorable workability.

[0150] The hydrophilic monomer (B) is not particularly limited. Examples thereof include, but are not limited to, 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-vinyl pyrrolidone, acrylic acid, methacrylic acid, polyethylene glycol mono(meth)acrylate, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinyl-N-ethylformamide, N-vinylformamide, and N-(4-hydroxyphenyl)maleimide. N,N-dimethylacrylamide, N,N-diethylacrylamide, N-vinylpyrrolidone and 2-hydroxyethyl methacrylate are preferred.

[0151] The hydrophilic monomer (B) may be any monomer soluble in water at any ratio. The hydroxyl-containing monomer of the first group may be the same as or different from the monomer (c) containing an amide group having one ethylenically unsaturated group.

[0152] In the curable composition of the present invention, component (B) may be used singly or in combination of two or more in any proportion. The content of component (B) in the total amount of the curable composition of the present invention is preferably 1 to 70% by weight, more preferably 1 to 50% by weight, even more preferably 5 to 40% by weight, particularly preferably 10 to 30% by weight, and most preferably 10 to 25% by weight. If the content is less than 1% by weight, the viscosity of the curable composition is too high, resulting in poor workability. If the content exceeds 70% by weight, a cured product with high oxygen permeability cannot be obtained.

[0153] Examples of the radical polymerization initiator (C) used in the curable composition of the present invention include thermal radical polymerization initiators and photoradical polymerization initiators.

[0154] The thermal radical polymerization initiator is not particularly limited, and examples thereof include various azo compounds or peroxides. Specifically, 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), 2,2'-azobisbutyric acid dimethyl ester, 2,2'-azobis(2,4,4-trimethylpentane) diisobutyryl peroxide, di(3,5,5-trimethylpentane) diisobutyryl peroxide, and di(3,5,5-trimethylpentane) diisobutyryl peroxide. peroxydicarbonate, diisopropyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(3-methoxybutyl) peroxydicarbonate, cumene peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl 1-Methylethylperoxyneodecanoate, tert-Hexylperoxyneodecanoate, tert-Butylperoxyneodecanoate, tert-Hexylperoxytrimethylacetate, tert-Butylperoxytrimethylacetate, 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-Butylperoxyisobutyrate, tert-Hexylperoxyisobutyrate Propyl carbonate, tert-butyl peroxymaleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxyacetic acid, tert-butyl peroxybenzoate, etc.

[0155] The photoradical polymerization initiator is not particularly limited, and examples thereof include various benzoin derivatives. Specifically, examples thereof include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-phenylmethyl]phenyl]-2-methyl-propane-1-one, methyl phenylglyoxylate, 2-methyl-1-(4-methylthiophenyl)-2-N-morpholinopropane-1-one, 2-phenylmethyl -2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)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-benzoyl oxime)], ethyl ketone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyl oxime), etc.

[0156] In the curable composition of the present invention, component (C) may be used singly or as a mixture of two or more in any proportion. The content of component (C) is preferably 0.01 to 1.0% by weight, and more preferably 0.05 to 0.5% by weight, of the total amount of the curable composition of the present invention. If the content is less than 0.01% by weight, the polymerization reaction may be insufficient, and a cured product with adequate strength may not be obtained. If the content is greater than 1.0% by weight, the polymerization rate may be rapid and the reaction may be uneven, making it impossible to obtain a cured product with adequate strength.

[0157] In order to improve the transparency of the curable composition of the present invention, a monomer (D) containing an alkyl group having 1 to 18 carbon atoms and having one ethylenically unsaturated group (hereinafter also referred to as "component (D)") may be added. Component (D) is not particularly limited, and the monomers exemplified in component (d) of the polymer (A) may be used. The content of the aforementioned component (D) in the curable composition of the present invention is not particularly limited. For example, the content of the component (D) in the total amount of the curable composition of the present invention is 1.0 to 30.0% by weight, preferably 3.0 to 18.0% by weight. If the amount is less than 1.0% by weight, there is no effect of improving transparency. In addition, if it exceeds 20.0% by weight, the cross-linking structure will be tight, and there will be a tendency to reduce the softness of the cured product.

[0158] A cross-linking monomer for enhancing the strength of the cured product can be used in the curable composition of the present invention. The cross-linking 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 cross-linking 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, dipentaerythritol hexa(meth)acrylate, etc. (Meth)acrylate crosslinking monomers; vinyl crosslinking 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-diallylmelamine, and divinylbenzene; and α,ω-methacryloyloxypropyl polydimethylsiloxane, etc., but not limited to these. The crosslinking monomers may be used alone or in combination of two or more.

[0159] The content of the crosslinking monomer in the curable composition of the present invention is not particularly limited. For example, the content is 0.1 to 5.0% by weight, preferably 0.3 to 3.0% by weight, based on the total weight of the curable composition. A content below 0.1% by weight will not enhance the strength of the cured product. Furthermore, a content above 5% by weight will tend to tighten the crosslinking structure and reduce the flexibility of the cured product.

[0160] [Silicone hydrogel contact lenses]

[0161] The silicone hydrogel contact lens of the present invention can be obtained by polymerizing the curable composition of the present invention. The silicone hydrogel contact lens of the present invention can be produced by known methods such as a method of polymerizing the curable composition of the present invention using a mold in the shape of a contact lens, or a method of polymerizing the curable composition of the present invention in a small tubular container, cutting the cured product into a lens shape, and polishing it.

[0162] [Example]

[0163] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the scope of the examples. In addition, unless otherwise specified, "parts" and "%" herein are by weight.

[0164] [Example 1]

[0165] (Process 1)

[0166] 67.2 g (grams) of toluene were placed in a flask equipped with a stirrer, a dropping funnel, a cooling tube, and a thermometer, and the temperature was raised to 95° C. under a nitrogen stream. A mixed solution of 0.61 g of 2-hydroxyethyl methacrylate, 51.1 g of silicone methacrylate (FM-0711 manufactured by JNC Co., Ltd., molecular weight 1,000), 24.3 g of N,N-dimethylacrylamide, 12.2 g of n-butyl acrylate, 1.83 g of 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 7.2 g of toluene, and 0.9 g of azobisisobutyronitrile was placed in the dropping funnel and added dropwise at a constant rate over 2 hours. The mixture was then aged at the same temperature for 3 hours.

[0167] (Process 2)

[0168] Next, 0.04 g of dibutyltin dilaurate as a reaction catalyst and 0.45 g of dibutylhydroxytoluene as a polymerization inhibitor were added, followed by 0.69 g of 2-isocyanatoethyl methacrylate, and the mixture was reacted at 95°C for 10 hours. Excess amine was added, and the mixture was back-titrated with hydrochloric acid. The isocyanate content after the reaction was measured, and it was confirmed that the value was less than 0.05% of the residual isocyanate content calculated from the calculated value. Thus, a polymer (P-1) before purification was obtained.

[0169] [Example 2]

[0170] (Step 3: Purification with supercritical carbon dioxide)

[0171] 20.0 g of the pre-purified polymer (P-1) obtained in Example 1 was placed in a sealed pressure vessel with an internal volume of approximately 140 mL. Carbon dioxide was then passed through the vessel at 70°C and a pressure of 25 MPa for 3 hours to dissolve impurities in the supercritical fluid of carbon dioxide. The supercritical fluid containing the impurities was then discharged. The pressure in the vessel was returned to normal, and the polymer (P-2) remaining in the vessel was obtained as the polymer (A) of the present invention. The molecular weight of the resulting polymer (P-2) was measured, and the weight-average molecular weight was 25,000.

[0172] [Comparative Example 1]: Purification using reduced pressure

[0173] 20.0 g of the pre-purified polymer (P-1) obtained in Example 1 was treated on a rotary evaporator at -0.01 kPa and 75°C for 3 hours to volatilize impurities. The pressure in the container was returned to normal to obtain a polymer (P-3). The molecular weight of the obtained polymer (P-3) was measured, and the weight-average molecular weight was 24,000.

[0174] [Example 3]

[0175] 111.9 g of toluene was placed in a flask equipped with a stirrer, a dropping funnel, a cooling tube, and a thermometer. The temperature was raised to 90°C under a nitrogen stream. A mixed solution of 1.40 g of 4-hydroxybutyl acrylate, 84.0 g of silicone methacrylate (FM-0711 manufactured by JNC Co., Ltd., molecular weight 1,000), 14.0 g of N,N-dimethylacrylamide, 25.2 g of n-butyl acrylate, 14 g of toluene, and 1.24 g of azobisisobutyronitrile was added dropwise to the dropping funnel at a constant rate over 2 hours. The mixture was then aged at the same temperature for 3 hours. Subsequently, 0.13 g of triphenylphosphine as a reaction catalyst and 0.13 g of dibutylhydroxytoluene as a polymerization inhibitor were added. The temperature was then raised to 95°C, 1.50 g of methacrylic anhydride was added, and the mixture was reacted at 95°C for 5 hours to obtain a polymer (P-4) before purification.

[0176] [Example 4]: Purification with supercritical carbon dioxide

[0177] 20.0 g of the pre-purified polymer (P-4) obtained in Example 3 was placed in a sealed pressure vessel with an internal volume of approximately 140 mL and treated with carbon dioxide at 40°C and a pressure of 25 MPa for 3 hours. The pressure in the vessel was returned to normal to obtain the reactive polymer (P-5) of the present invention. The molecular weight of the resulting polymer was measured, and the weight-average molecular weight was 64,000.

[0178] [Comparative Example 2]: Purification using reduced pressure

[0179] 20.0 g of the pre-purified polymer (P-4) obtained in Example 3 was treated using a rotary evaporator at a reduced pressure of -0.01 kPa and 75°C for 3 hours. The container was returned to normal pressure to obtain a polymer (P-6). The molecular weight of the obtained polymer was measured, and the weight-average molecular weight was 54,000.

[0180] The GPC chart of polymer (P-5) is shown in Figure 1 The GPC graph of the polymer (P-6) is shown in Figure 2 The GPC diagram of FM-0711 is shown in Figure 3 middle.

[0181] [Example 5]

[0182] (Process 1)

[0183] 63.8 g of toluene was placed in a flask equipped with a stirrer, a dropping funnel, a cooling tube, and a thermometer, and the temperature was raised to 95° C. under a nitrogen stream. A mixed solution of 1.36 g of 2-isocyanatoethyl methacrylate, 48.0 g of polysilicone methacrylate (FM-0711 manufactured by JNC Co., Ltd., molecular weight 1,000), 22.9 g of N,N-dimethylacrylamide, 11.4 g of n-butyl acrylate, 1.71 g of 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd.), 6.8 g of toluene, and 0.9 g of azobisisobutyronitrile was placed in the dropping funnel and added dropwise at a constant rate over 2 hours. The mixture was then aged at the same temperature for 3 hours.

[0184] (Process 2)

[0185] Next, 0.04 g of dibutyltin dilaurate as a reaction catalyst and 0.45 g of dibutylhydroxytoluene as a polymerization inhibitor were added, followed by 1.20 g of 2-hydroxyethyl methacrylate, and the mixture was reacted at 95°C for 10 hours. Excess amine was added, and the isocyanate content after the reaction was determined by back titration with hydrochloric acid. The value was confirmed to be less than 0.05% of the residual isocyanate content determined from the calculated value, thereby obtaining a polymer (P-7) before purification.

[0186] [Example 6]

[0187] (Step 3: Purification with supercritical carbon dioxide)

[0188] 20.0 g of the pre-purified polymer (P-7) obtained in Example 1 was placed in a sealed pressure vessel with an internal volume of approximately 140 mL. Carbon dioxide was then passed through the vessel at 70°C and a pressure of 25 MPa for 3 hours to dissolve impurities in the supercritical fluid. The supercritical fluid containing the impurities was then discharged from the pressure vessel. The pressure in the vessel was returned to normal, and the polymer (P-8) remaining in the vessel was obtained as the polymer (A) of the present invention. The molecular weight of the resulting polymer (P-8) was measured, and the weight-average molecular weight was 29,000.

[0189] [Comparative Example 3]: Purification using reduced pressure

[0190] 20.0 g of the pre-purified polymer (P-7) obtained in Example 5 was treated on a rotary evaporator at -0.01 kPa and 75°C for 3 hours to volatilize impurities. The container was returned to normal pressure to obtain a polymer (P-9). The molecular weight of the obtained polymer (P-9) was measured, and the weight-average molecular weight was 28,000.

[0191] [Example 7]

[0192] (Process 1)

[0193] 61.3 g of toluene was placed in a flask equipped with a stirrer, dropping funnel, cooling tube, and thermometer. The temperature was raised to 95°C under a nitrogen stream. A mixed solution of 2.22 g of 2-hydroxyethyl methacrylate, 46.6 g of polysilicone methacrylate (FM-0711 manufactured by JNC Co., Ltd., molecular weight 1,000), 22.2 g of N,N-dimethylacrylamide, 11.1 g of n-butyl acrylate, 6.5 g of toluene, and 0.82 g of azobisisobutyronitrile was added dropwise at a constant rate over 2 hours. The mixture was then aged at the same temperature for 3 hours.

[0194] (Process 2)

[0195] Next, 1.74 g of triethylamine as a reaction catalyst and 0.42 g of dibutylhydroxytoluene as a polymerization inhibitor were added, the temperature was lowered to 60°C, and 1.78 g of methacryloyl chloride was added with stirring. The reaction was allowed to react for 2 hours. The reaction solution was pressure filtered through filter paper with an auxiliary particle size of 1 μm to remove triethylamine hydrochloride, obtaining a polymer (P-10) before purification.

[0196] [Example 8]

[0197] (Step 3: Purification with supercritical carbon dioxide)

[0198] 20.0 g of the pre-purified polymer (P-10) obtained in Example 7 was placed in a sealed pressure vessel with an internal volume of approximately 140 mL. A mixture of 98% by weight carbon dioxide and 2% by weight 2-propanol was passed through the vessel at 70°C and 25 MPa for 3 hours to dissolve impurities in the supercritical fluid mixture of carbon dioxide and 2-propanol. The supercritical fluid containing the dissolved impurities was simultaneously discharged from the pressure vessel. Subsequently, carbon dioxide was passed through the vessel at 70°C and 25 MPa for 2 hours, and the 2-propanol was discharged from the pressure vessel. The pressure in the vessel was returned to normal, and the polymer (P-11) remaining in the vessel was obtained as the polymer (A) of the present invention. The molecular weight of the resulting polymer (P-11) was measured, and the weight-average molecular weight was 37,000.

[0199] [Comparative Example 4]: Purification using reduced pressure

[0200] 20.0 g of the pre-purified polymer (P-10) obtained in Example 1 was treated using a rotary evaporator at a reduced pressure of -0.01 kPa and 75°C for 3 hours to volatilize and remove impurities. The container was returned to normal pressure to obtain a polymer (P-12). The molecular weight of the obtained polymer (P-12) was measured, and the weight-average molecular weight was 36,000.

[0201] In each of the Examples and Comparative Examples, various physical properties were measured as follows.

[0202] (weight average molecular weight)

[0203] The weight average molecular weight (Mw) is measured by GPC (gel permeation chromatography) under the following conditions.

[0204] Analytical equipment: GPC HLC-8320GPC manufactured by Tosoh Corporation

[0205] Column: SuperMultipore HZ-H (2 tubes) manufactured by Tosoh Corporation

[0206] Column temperature: 40°C

[0207] Flow rate: 0.35ml / min

[0208] Solvent: Tetrahydrofuran

[0209] Detector: Differential refractometer

[0210] Standard sample: polystyrene

[0211] (Quantitative determination of polysilicone methacrylate monomer FM-0711)

[0212] The amount of the polysilicone methacrylate monomer FM-0711 contained in the polymer was quantified using LC-MS (liquid chromatography mass spectrometry).

[0213] Analysis device: UltiMate 3000 manufactured by Thermo Fisher Scientific

[0214] Column: CORTECS C18

[0215] Column temperature: 40°C

[0216] Mobile phase A: acetonitrile / THF (50 / 50)

[0217] Mobile phase B: 5 mM ammonium acetate in water

[0218] Detector: Photodiode array (PDA) detector 190 to 800 nm, electrospray ionization (ESI) ± (mass range 150 to 2250)

[0219] (Quantitative determination of toluene, monomer, and initiator)

[0220] Using tridecane as an internal standard, the toluene, monomer, and initiator remaining in polymers (P-2), (P-3), (P-5), and (P-6) were quantified by GC-MS (gas chromatography-mass spectrometry).

[0221] Analytical equipment: GC-2010 manufactured by Shimadzu Corporation

[0222] Column: HP-5MS 30m-0.25mm-0.25μm

[0223] Carrier gas: He (helium) 1.2 mL / min

[0224] Oven: 50°C (2 minutes) - 10°C / minute - 300°C (33 minutes)

[0225] Inlet: split (30:1), 250℃

[0226] Detector: Flame Ionization Detector (FID)

[0227] Table 1 shows the results of measuring the amounts of impurities contained in polymers (P-2) and (P-3).

[0228] [Table 1]

[0229] Table 1

[0230]

[0231] The abbreviations of the compounds in Table 1 are as follows.

[0232] FM-0711: Silicone methacrylate (manufactured by JNC)

[0233] 2-HEMA: 2-hydroxyethyl methacrylate

[0234] nBA: n-butyl acrylate

[0235] DMA: N,N-dimethylacrylamide

[0236] RUVA-93: 2-(2'-Hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole

[0237] MOI: 2-isocyanatoethyl methacrylate

[0238] AIBN: Azobisisobutyronitrile

[0239] Table 2 shows the results of measuring the amounts of impurities contained in polymers (P-5) and (P-6).

[0240] [Table 2]

[0241] Table 2

[0242]

[0243] Although the impurities in FM-0711 are believed to be by-products during the production of FM-0711, they have not yet been accurately identified. Table 2 shows the components eliminated after the reaction of MMA (methacrylic acid) polymers with methacrylic anhydride.

[0244] The abbreviations of the compounds in Table 2 are as follows.

[0245] FM-0711: Silicone methacrylate (manufactured by JNC)

[0246] 4-HBA: 4-hydroxybutyl acrylate

[0247] nBA: n-butyl acrylate

[0248] DMA: N,N-dimethylacrylamide

[0249] MAAH: Methacrylic Anhydride

[0250] MAA: Methacrylic acid

[0251] AIBN: Azobisisobutyronitrile

[0252] The toluene, monomers, and initiator remaining in the polymers (P-8) and (P-9) were quantified by GC (gas chromatography) using tridecane as an internal standard.

[0253] Analytical instrument: Agilent 7890

[0254] Column: HP-5MS 30m-0.25mm-0.25μm

[0255] Carrier gas: He (helium) 1.2 mL / min

[0256] Oven: 80°C (2 minutes) - 10°C / minute - 300°C (21 minutes)

[0257] Inlet: split (30:1), 300℃

[0258] Detector: Flame Ionization Detector (FID)

[0259] Table 3 shows the results of measuring the amounts of impurities contained in polymers (P-8) and (P-9).

[0260] [Table 3]

[0261] Table 3

[0262]

[0263] The abbreviations of the compounds in Table 3 are as follows.

[0264] FM-0711: Silicone methacrylate (manufactured by JNC)

[0265] 2-HEMA: 2-hydroxyethyl methacrylate

[0266] nBA: n-butyl acrylate

[0267] DMA: N,N-dimethylacrylamide

[0268] RUVA-93: 2-(2'-Hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole

[0269] MOI: 2-isocyanatoethyl methacrylate

[0270] AIBN: Azobisisobutyronitrile

[0271] Using tridecane as an internal standard, the toluene and 2-propanol monomers remaining in polymers (P-11) and (P-12) were quantified by GC (gas chromatography).

[0272] Analytical instrument: Agilent 7890

[0273] Column: HP-5MS 30m-0.25mm-0.25μm

[0274] Carrier gas: He 1.2mL / min

[0275] Oven: 40℃ (5 minutes) - 10℃ / minute - 220℃ (18 minutes)

[0276] Inlet: split (30:1), 200℃

[0277] Detector: Flame Ionization Detector (FID)

[0278] The amount of initiator remaining in polymers (P-11) and (P-12) was quantified by GC (gas chromatography) using tridecane as an internal standard.

[0279] Analytical instrument: Agilent 7890

[0280] Column: HP-5MS 30m-0.25mm-0.25μm

[0281] Carrier gas: He 1.2mL / min

[0282] Oven: 80°C (2 minutes) - 10°C / minute - 300°C (21 minutes)

[0283] Inlet: split (30:1), 300℃

[0284] Detector: Flame Ionization Detector (FID)

[0285] The amount of triethylamine remaining in the polymers (P-11) and (P-12) was quantified by GC (gas chromatography) using tridecane as an internal standard.

[0286] Analytical instrument: Agilent 8890

[0287] Column: InertCap for Amines 30m-0.32mm

[0288] Carrier gas: He 1.2mL / min

[0289] Oven: 50℃ (3 minutes) - 10℃ / minute - 220℃ (10 minutes)

[0290] Inlet: split (30:1), 260℃

[0291] Detector: Flame Ionization Detector (FID)

[0292] Table 4 shows the results of measuring the amounts of impurities contained in polymers (P-11) and (P-12).

[0293] [Table 4]

[0294] Table 4

[0295]

[0296] The abbreviations of the compounds in Table 4 are as follows.

[0297] FM-0711: Silicone methacrylate (manufactured by JNC)

[0298] nBA: n-butyl acrylate

[0299] DMA: N,N-dimethylacrylamide

[0300] 2-HEMA: 2-hydroxyethyl methacrylate

[0301] AIBN: Azobisisobutyronitrile

[0302] In Table 4, methacrylic acid is a reaction product of methacrylic acid chloride and water. 2-Propanol was used as an azeotropic agent used in the purification of supercritical carbon dioxide.

[0303] [Preparation of Curable Composition]

[0304] [Example 9]

[0305] In a glass bottle, 7.2 g of polymer (P-2) as polymer (A); 0.9 g of N-vinylpyrrolidone (Methyl pyrrolidone), 0.6 g of N,N-diethylacrylamide, 0.4 g of methacrylic acid, and 4-hydroxybutyl acrylate as hydrophilic monomers (B); 0.6 g of lauryl acrylate as a monomer (D) containing an alkyl group having 1 to 18 carbon atoms; and 0.05 g of 1,1'-azobis(cyclohexane-1-carbonitrile) as a radical polymerization initiator (C) were mixed and mixed using a rotary mixer to obtain a curable composition of Example 9.

[0306] [Example 10]

[0307] In a glass bottle, 8.0 g of polymer (P-5) as polymer (A); 2.0 g of N,N-diethylacrylamide and 0.01 g of ethylene glycol dimethacrylate as hydrophilic monomers (B); and 0.05 g of azobisisobutyronitrile as a radical polymerization initiator (C) were mixed using a rotary mixer to obtain a curable composition of Example 10.

[0308] [Example 11]

[0309] In a glass bottle, 7.2 g of polymer (P-8) as polymer (A); 0.9 g of N-vinylpyrrolidone (Methyl pyrrolidone), 0.6 g of N,N-diethylacrylamide, 0.4 g of methacrylic acid, and 0.3 g of 4-hydroxybutyl acrylate as hydrophilic monomers (B); 0.6 g of lauryl acrylate as a monomer having an alkyl group with 1 to 18 carbon atoms (D); and 0.05 g of 1,1'-azobis(cyclohexane-1-carbonitrile) as a radical polymerization initiator (C) were mixed and mixed using a rotary mixer to obtain a curable composition of Example 11.

[0310] [Manufacturing of silicone hydrogel contact lenses]

[0311] The curable compositions obtained in Examples 9 to 11 were placed in a female polypropylene contact lens mold, and the corresponding male and female molds were assembled. The assembled contact lens molds were polymerized and cured at 105° C. for 2 hours under a nitrogen atmosphere.

[0312] After polymerization is complete, the male and female molds are separated, and the male and female molds with the cured product attached are immersed in a 60°C pure water / ethanol mixture (90 / 10 by volume) for one hour. The cured product is then released from the male and female molds. The resulting cured product is then immersed in physiological saline for one hour and then sterilized by autoclaving at 121°C for 30 minutes to produce a silicone hydrogel contact lens.

[0313] The resulting silicone hydrogel contact lenses all appeared perfectly round when viewed from directly above, and their light transmittance, measured using a spectrophotometer, showed transparency of over 90%.

[0314] [Example 12]

[0315] In a glass bottle, 7.2 g of polymer (P-11) as polymer (A); 2.3 g of N,N-diethylacrylamide as hydrophilic monomer (B); 0.6 g of n-butyl acrylate as monomer (D) containing an alkyl group having 1 to 18 carbon atoms; and 0.05 g of azobisisobutyronitrile as a radical polymerization initiator (C) were mixed using a rotary mixer to obtain a curable composition of Example 12.

[0316] [Example 13]

[0317] [Manufacturing of silicone hydrogel contact lenses]

[0318] The curable composition obtained in Example 12 was placed in a female mold of a polypropylene contact lens mold, and the corresponding male and female molds were assembled. The assembled contact lens mold was polymerized and cured at 105° C. for 2 hours under a nitrogen atmosphere.

[0319] After polymerization was completed, the male and female molds were separated, and the male and female molds with the hardened material attached were immersed in a 60°C pure water / ethanol mixture (95 / 5 by volume) for one hour. The hardened material was then removed from the male and female molds and then immersed in physiological saline for one hour to obtain a swelled body. The resulting swelled body was sterilized by high-pressure steam at 121°C for 30 minutes to obtain the silicone hydrogel contact lens of Example 13.

[0320] The silicone hydrogel contact lens of Example 13 exhibited a perfectly circular shape when viewed from directly above. Furthermore, when light transmittance was measured using a spectrophotometer, it had a transparency of 90% or higher.

[0321] [Example 14]

[0322] [Manufacturing of silicone hydrogel contact lenses]

[0323] The curable composition obtained by the same method as in Example 12 was polymerized and cured by the same method as in Example 13. The male and female molds were then separated, and the male and female molds with the cured product attached were immersed in a 60°C pure water / IPA (isopropyl alcohol) mixture (50 / 50 by volume) for 1 hour. The cured product was then removed from the male and female molds and then immersed in physiological saline for 1 hour to obtain a swelled body. The resulting swelled body was sterilized by high-pressure steam at 121°C for 30 minutes to obtain the silicone hydrogel contact lens of Example 14.

[0324] The silicone hydrogel contact lens of Example 14 exhibited a perfectly circular shape when viewed from directly above. Furthermore, when light transmittance was measured using a spectrophotometer, it had a transparency of 90% or higher.

[0325] [Comparative Example 5]

[0326] [Preparation of curable composition]: Preparation using monomers

[0327] In a glass bottle, 4.2 g of polysilicone methacrylate (FM-0711 manufactured by JNC Co., Ltd., molecular weight 1,000) as component (b); 2.3 g of N,N-diethylacrylamide and 2.0 g of N,N-dimethylacrylamide as hydrophilic monomers (B); 1.5 g of n-butyl acrylate as a monomer (D) containing an alkyl group having 1 to 18 carbon atoms; 0.2 g of ethylene glycol di(meth)acrylate as a crosslinking monomer; and 0.05 g of azobisisobutyronitrile as a radical polymerization initiator (C) were mixed and mixed using a rotary mixer to obtain a curable composition of Comparative Example 5.

[0328] [Comparative Example 6]

[0329] [Manufacturing of silicone hydrogel contact lenses]

[0330] The obtained curable composition was placed in a female mold of a polypropylene contact lens mold, and the corresponding male and female molds were assembled. The assembled contact lens mold was polymerized and cured at 105° C. for 2 hours under a nitrogen atmosphere.

[0331] After polymerization was completed, the male and female molds were separated, and the male and female molds with the hardened material attached were immersed in a 60°C pure water / ethanol mixture (95 / 5 by volume) for one hour. The hardened material was then removed from the male and female molds and then immersed in physiological saline for one hour to obtain a swelled body. The resulting swelled body was sterilized by high-pressure steam at 121°C for 30 minutes to obtain the silicone hydrogel contact lens of Comparative Example 6.

[0332] The light transmittance of the obtained silicone hydrogel contact lens of Comparative Example 6 was measured using a spectrophotometer. Although the lens had a transparency of 90% or more, it was confirmed that the lens did not have a perfectly round shape but was distorted when viewed from directly above.

[0333] [Comparative Example 7]

[0334] [Manufacturing of silicone hydrogel contact lenses]

[0335] The curable composition obtained by the same method as in Comparative Example 2 was polymerized and cured by the same method as in Comparative Example 7. The male and female molds were then separated, and the male (male) mold with the cured product attached was immersed in a 60°C pure water / IPA mixture (50 / 50 by volume) for 1 hour. The cured product was then removed from the male (male) mold and then immersed in physiological saline for 1 hour to obtain a swelled body. The resulting swelled body was then sterilized by high-pressure steam at 121°C for 30 minutes to obtain the silicone hydrogel contact lens of Comparative Example 7.

[0336] The light transmittance of the obtained silicone hydrogel contact lens of Comparative Example 7 was measured using a spectrophotometer. Although the lens had a transparency of 90% or more, it was confirmed that the lens did not have a perfectly circular shape and was deformed when observed from directly above.

[0337] Twenty-five silicone hydrogel contact lenses obtained in Examples 13 and 14, and Comparative Examples 6 and 7 were immersed in 5 mL of acetone and shaken at room temperature for 72 hours, followed by preparing an acetone extract.

[0338] The polysiloxane monomer FM-0711 in the acetone extract was quantified using LC-MS (liquid chromatography-mass spectrometry). The concentration of the standard solution was converted to the concentration of the test sample, and a calibration curve corresponding to 0.1, 0.5, 1.5, and 10 ppm was created. The results are shown in Table 5.

[0339] The polysiloxane monomer FM-0711 in the acetone extract was quantified using LC-MS (liquid chromatography-mass spectrometry). The concentration of the standard solution was converted to the concentration of the test sample, and a calibration curve corresponding to 0.1, 0.5, 1.5, and 10 ppm was created. The results are shown in Table 5.

[0340] Analytical device: Q-Exactive manufactured by Thermo Fisher Scientific

[0341] Column: CORTECS C18

[0342] Column temperature: 40°C

[0343] Mobile phase A: acetonitrile / THF (50 / 50)

[0344] Mobile phase B: 5 mM ammonium acetate in water

[0345] Gradient: A / B = 50 / 50-(5)-95 / 5(10)

[0346] Detector: Photodiode array (PDA) detector 190 to 800 nm, electrospray ionization (ESI) ± (mass range 200 to 2500)

[0347] [Table 5]

[0348] Test sample FM-0711 quantity Example 13 Less than 0.1ppm Example 14 0.1ppm Comparative Example 6 8.5ppm Comparative Example 7 0.5ppm

[0349] This application claims priority based on Japanese Patent Application No. 2022-206597 filed on December 23, 2022, Japanese Patent Application No. 2023-146954 filed on September 11, 2023, and Japanese Patent Application No. 2023-181047 filed on October 20, 2023.

[0350] [Industrial Applicability]

[0351] The polymer of the present invention has high purity. Since no silicon-containing monomer remains after curing of the curing composition using the polymer, it does not need to be cleaned with a large amount of organic solvent, and can provide inexpensive contact lenses.

Claims

1. A method for producing a polymer (A), comprising the following steps: (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 a polymer (A2); and (Step 3) A step of purifying the polymer (A2) using a subcritical or supercritical fluid to obtain the polymer (A); wherein, The first monomer is selected from the following group 1 or group 2: Group 1 composed of monomers containing hydroxyl groups, The second group consisting of (meth)acrylic acid isocyanate compounds, (meth)acrylic acid anhydride and (meth)acrylic acid halide; The second monomer is selected from the other of the first group or the second group.

2. The method for producing a polymer (A) according to claim 1, wherein in the (step 1), the first monomer (a) is polymerized together with a silicon-containing monomer (b) having one ethylenically unsaturated group. 3 . The method for producing a polymer (A) according to claim 2 , wherein in the (step 1), an amide group-containing monomer (c) is further polymerized.

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

5. The method for producing a polymer (A) according to any one of claims 1 to 4, wherein The first monomer is a hydroxyl group-containing monomer.

6. The method for producing a polymer (A) according to claim 5, wherein The second monomer is an isocyanate compound of (meth)acrylic acid.

7. The method for producing a polymer (A) according to claim 5, wherein The second monomer is (meth)acrylic acid anhydride.

8. The method for producing a polymer (A) according to claim 5, wherein The second monomer is a halide of (meth)acrylic acid.

9. The method for producing a polymer (A) according to any one of claims 1 to 4, wherein The first monomer is an isocyanate compound of (meth)acrylic acid, The second monomer is a hydroxyl group-containing monomer.

10. The method for producing a polymer (A) according to any one of claims 1 to 9, wherein Only carbon dioxide is used as the aforementioned subcritical or supercritical fluid.

11. The method for producing a polymer (A) according to any one of claims 1 to 9, wherein A mixture of carbon dioxide and an entrainer is used as the subcritical or supercritical fluid.

12. The method for producing a polymer (A) according to claim 11, wherein The mixture of carbon dioxide and entrainer is composed of 80.0 to 99.9 weight percent of carbon dioxide and 0.1 to 20.0 weight percent of entrainer.

13. The method for producing a polymer (A) according to claim 11 or 12, wherein The azeotropic agent is one or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol, and 1,4-dioxane. 14 . The method for producing a polymer (A) according to claim 1 , wherein the polymer (A) has a weight average molecular weight of 5,000 to 300,000.

15. A method for producing a curable composition, wherein: The curable composition comprises the polymer (A) according to any one of claims 1 to 14, a hydrophilic monomer (B), and a radical polymerization initiator.

16. A method for producing a hardened product, wherein: The cured product is obtained by curing the curable composition according to claim 15.

17. The method for producing a curable composition according to claim 15, wherein: The hardenable composition is used for contact lenses. 18 . A method for producing a silicone hydrogel contact lens, comprising using the curable composition for contact lens according to claim 17 .

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