Soft eye lenses and methods for manufacturing the same

Abstract

An objective of the present invention is to provide a method for manufacturing a soft ophthalmic lens in which a surface of the lens is hydrophilized by means of plasma processing, wherein a base material surface can be sufficiently hydrophilized by performing, once, a reaction between the base material and a hydrophilic polymer. Another object of the present invention is to provide a soft ophthalmic lens having sufficient hydrophilicity, using only one layer comprising a hydrophilic polymer on a base material surface.　A base material including a hydrocarbon group-containing polysiloxane is subjected to plasma processing using an inert gas such as nitrogen, to form a radical including Si-CH2 on the base material surface, and radical transfer to a hydrophilic polymer occurs, thereby causing the hydrophilic polymer to bind to the base material surface by recombination, with the base material, of a radical generated in the hydrophilic polymer.

Description

Technical Field

[0001] The present invention relates to a novel soft contact lens with surface hydrophilization and a method for manufacturing the same.

Background Art

[0002] Currently, as soft contact lenses (SCLs), lenses made of silicone-containing materials with high oxygen permeability are widely popular, including high water content soft contact lenses (SHGCLs) made of hydrogel materials having a high water content of about 25% to about 80%, and low or non-water content contact lenses (FGPCLs) with a water content of 10% or less. Since SHGCLs contain silicone, they have higher oxygen permeability compared to previous SCLs and are also excellent in terms of wearing comfort. However, due to their high water content, the drying sensation during wearing caused by evaporation of water from the lenses has become a problem. On the other hand, FGPCLs usually have a higher silicone content, so they have higher oxygen permeability and are low or non-water content, and thus are expected to reduce the drying sensation during wearing.

[0003] On the other hand, FGPCLs have had problems in that the high hydrophobicity / water repellency of the lens surface gives a sense of discomfort during wearing, and the lubricity and stain resistance are low.

[0004] Regarding SHGCLs and FGPCLs having such problems, various techniques for modifying the lens surface have been studied. For example, a base material obtained by polymerizing polydimethylsiloxane (PDMS) and hydrophilic monomers such as N,N-dimethylacrylamide and ethylene glycol dimethacrylate is hydrated with water, and then sequentially immersed in an aqueous solution of polyvinyl alcohol and a mixed aqueous solution of polyvinylpyrrolidone and polyethylene glycol (PEG) to hydrophilize the lens surface, and a soft contact lens has been proposed (Patent Document 1).

[0005] Furthermore, a soft ophthalmic lens has been proposed in which an ionic chain polymer is incorporated into a silicone-containing soft lens substrate having a mesh structure, and after the ionic chain polymer is charged, a hydrophilic polymer having the opposite charge is adsorbed to make the lens surface hydrophilic (Patent Document 2).

[0006] Furthermore, a silicone hydrogel soft ophthalmic lens has been proposed in which a silicone hydrogel lens substrate obtained by polymerizing a siloxane-containing monomer or macromer with a vinyl monomer mixture and N-vinylpyrrolidone is immersed in an aqueous solution of an anionic polymer having carboxyl groups, such as polyacrylic acid, to adsorb the anionic polymer onto the substrate surface, and this is crosslinked with a water-soluble, thermally crosslinkable hydrophilic polymer such as polyamidoamine epichlorohydrin to form a hydrophilic coating layer (Patent Document 3).

[0007] Furthermore, soft ophthalmic lenses have been disclosed in which the lens surface is made hydrophilic by alternately adsorbing acidic polymers and basic polymers onto an SHGCL substrate or FGPCL substrate using a so-called LbL method (Patent Documents 4 to 8).

[0008] These soft ophthalmic lenses all involve adsorbing hydrophilic polymers onto a substrate via non-covalent bonds. As a result, the coating layer composed of hydrophilic polymers was easily detached from the lens surface by physical stimuli such as rubbing. Furthermore, in these soft ophthalmic lenses, adsorbing hydrophilic polymers onto the substrate surface only once is insufficient, resulting in partial exposure of the substrate surface. Therefore, a second hydrophilic polymer is adsorbed or bonded to the first hydrophilic polymer as a base. This resulted in a complex manufacturing process, which contributed to high manufacturing costs.

[0009] In contrast, soft ophthalmic lenses have also been developed in which a hydrophilic coating layer is provided by covalently bonding hydrophilic polymers to a substrate using various methods.

[0010] For example, one method involves placing a substrate in a gas atmosphere containing a coating material and performing plasma polymerization to form a hydrophilic coating layer on the substrate. Specifically, a method has been proposed in which a lens substrate made of polydimethylsiloxane (PDMS) is placed in a glow discharge polymerization apparatus, a mixed gas of hydrocarbons such as methane and halogenated hydrocarbons such as perfluoromethane is introduced after depressurization, plasma is generated by glow discharge, and a coating layer having a graphite-like, tightly crosslinked structure is formed on the substrate (Patent Document 9). Furthermore, this document proposes a method in which a lens substrate made of PDMS is placed in a glow discharge polymerization apparatus, a mixed gas of hydrogen and halogenated hydrocarbons such as tetrafluoroethylene is introduced after depressurization, plasma is generated by glow discharge to form a coating layer on the substrate, and then oxygen is introduced into the atmosphere and oxygen plasma is generated by glow discharge to form a hydrophilic coating layer.

[0011] Furthermore, a method has been proposed in which a silicone-containing lens substrate is placed in a mixed gas of a coating material such as an alkane or N-vinylpyrrolidone and an inert gas such as air, oxygen, or argon, and a hydrophilic coating layer is formed by plasma polymerization (Patent Document 10).

[0012] In these plasma polymerization methods for forming coating layers, the coating material is exposed to plasma to form radicals, which then react with the substrate surface. As a result, a coating layer is formed that differs from the inherent properties of the hydrophilic polymer. For example, when plasma polymerization is performed using N-vinylpyrrolidone, various types of radicals are generated, all of which participate in the polymerization reaction to form a complex cross-linked structure (Non-Patent Literature 1). Furthermore, decomposition products of N-vinylpyrrolidone are also generated in the gas phase. Therefore, the coating layer formed by plasma polymerization is completely different from polyvinylpyrrolidone and is closer to amorphous carbon. For this reason, there is a demand for a technology that can form a coating layer that possesses the inherent properties of the hydrophilic polymer.

[0013] To address such requirements, a method has been disclosed in which a lens substrate is activated by plasma treatment, and a coating layer is formed by reacting the activated surface with a hydrophilic polymer having functional groups. For example, a method has been proposed in which a substrate is plasma-treated in air, oxygen, methane, CO2, a mixed gas of oxygen and methane, a mixed gas of CO2 and methane, or a mixed gas of methane and air, and after treatment, a base coating layer is formed by immersing it in an acidic solution of an anionic polymer having carboxyl groups or an alkaline solution of a cationic polymer having primary / secondary amino groups, and a hydrogel coating layer is formed on an SHGCL substrate or an FGPCL substrate by crosslinking this base coating layer with a hydrophilic polymer having a predetermined reactive group (Patent Documents 11 and 12).

[0014] Furthermore, a method has been proposed in which a polysiloxane-based FGPCL substrate is treated with oxygen plasma to generate silanol groups (Si-OH) on its surface, and a hydrophilic polymer having silane coupling groups at its terminus is subjected to a silane coupling reaction to form a hydrophilic layer on the substrate surface (Patent Document 13).

[0015] Furthermore, a method has been disclosed in which a first polymer species having a predetermined reactive group is covalently bonded to the surface of an FGPCL substrate containing 75% or more silicone, and then a second polymer species having a predetermined reactive group is crosslinked with the first polymer species to form a hydrogel layer. Plasma treatment is listed as one of the various means for covalently bonding the first polymer species to the substrate (Patent Documents 14 and 15). However, these documents do not describe specific manufacturing examples using plasma treatment, nor do they show specific conditions for covalently bonding the first polymer species to the substrate using plasma treatment. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] Japanese Patent Publication No. 2020-42253 [Patent Document 2] Patent No. 6230880 [Patent Document 3] U.S. Patent Application Publication No. 2017 / 0165932 [Patent Document 4] Patent No. 4551219 [Patent Document 5] Patent No. 5064498 [Patent Document 6] Patent No. 4634603 [Patent Document 7] Japanese Patent Publication No. 2016-28292 [Patent Document 8] Japanese Patent Publication No. 2020-8873 [Patent Document 9] U.S. Patent No. 4312575 [Patent Document 10] European Patent Application Publication No. 1043605 [Patent Document 11] Patent No. 6592189 [Patent Document 12] Patent No. 6680870 [Patent Document 13] Japanese Patent Publication No. 2015-158615 [Patent Document 14] Special Publication 2017-530423 [Patent Document 15] Special Publication 2019-219666 [Patent Document 16] International Publication No. 2017 / 175705 [Non-patent literature]

[0017] [Non-Patent Document 1] C. Dispenza, et. al., Radiation Physics and Chemistry, 2020, Vol.174, 108900. [Non-Patent Document 2] J. Wu, et. al., Lab Chip, 2014, 14, 1564-1571. [Non-Patent Document 3] SRA Kratz, et. al., Scientific Reports, 2020, 10:1400. [Non-Patent Document 4] E. Ismail, et. al., Chemistry Letters, 2020, CL-200504. [Non-Patent Document 5] P. Zhang, et. al., Phys. Chem. Chem. Phys., 2014, Vol.16, 17479―17486. [Non-Patent Document 6] I. Auzmendi-Murua, et. al., Journal of Physical Chemistry A, 2014, Vol.118, 3147―3167. [Overview of the Initiative] [Problems that the invention aims to solve]

[0018] Thus, in conventional soft ophthalmic lenses with a hydrophilic coating layer formed by plasma treatment, plasma such as air, oxygen, methane, or CO2 partially decomposes silicone (or polysiloxane compound) such as PDMS to generate hydroxyl groups or hydrocarbons containing hydroxyl groups. These groups then form covalent bonds (e.g., ester bonds, amide bonds, siloxane bonds) between these groups and the functional groups of the hydrophilic polymer (e.g., carboxyl groups, amino groups, silane wrapping groups). However, in conventional methods, the substrate surface obtained by covalently bonding a first hydrophilic polymer to the substrate surface by plasma treatment is not sufficiently hydrophilic. Therefore, a second hydrophilic polymer is further adsorbed or crosslinked onto the first hydrophilic polymer to make the substrate surface hydrophilic. Consequently, there is a need for a plasma treatment manufacturing method that is simpler and reduces manufacturing costs. The object of the present invention is to meet such demands, and more specifically, to provide a method for manufacturing soft ophthalmic lenses in which the surface of the substrate can be sufficiently hydrophilized by performing a reaction between the substrate and a hydrophilic polymer only once, in a method for manufacturing soft ophthalmic lenses in which the surface of the substrate is hydrophilized by plasma treatment. Another object of the present invention is to provide soft ophthalmic lenses that have sufficient hydrophilicity with only one layer of hydrophilic polymer on the substrate surface. [Means for solving the problem]

[0019] To address the above-mentioned problem, namely, to provide sufficient hydrophilicity to a silicone-containing lens with a single layer of hydrophilic polymer, the inventors first clarified the conventional mechanism of bonding hydrophilic polymers to a substrate by plasma treatment. Conventional methods for bonding hydrophilic polymers to a substrate using air or oxygen plasma treatment involve forming Si-OH groups on the substrate surface due to the reactive oxygen species generated by the plasma treatment, and then reacting these Si-OH groups with the functional groups of the hydrophilic polymer. However, these Si-OH groups react strongly with the Si-OH groups of other silicones to form Si-O-Si bonds, and the amount of Si-OH on the substrate surface decreases over time after plasma treatment (Non-Patent Documents 2 and 3). Furthermore, the functional groups (carboxyl groups, amino groups) of the hydrophilic polymer do not react with the Si-OH groups of silicones in a neutral environment, and as described in Patent Document 12, they need to react with or be adsorbed by the Si-OH groups on the substrate surface under acidic or alkaline conditions. From these points, it was confirmed that conventional methods for bonding hydrophilic polymers to a substrate using air or oxygen plasma treatment, or simply forming a base coating layer, make it difficult to impart sufficient hydrophilicity.

[0020] On the other hand, in plasma treatment using a gas that mixes carbon atoms such as methane or CO2 with air or oxygen, reactive groups such as Si-CH2-OH can be introduced into the PDMS surface, and these reactive groups are more stable than Si-OH. However, this plasma treatment also generates OH groups on the substrate surface and reacts them with the functional groups of the hydrophilic polymer, and it is difficult to impart sufficient hydrophilicity through this reaction alone. Furthermore, plasma treatment is performed using an oxygen-containing (mixed) gas to induce such a reaction, but oxygen or carbon-containing gases such as methane or CO2 generate corresponding active species through plasma treatment, and these react with radicals on the substrate surface to form stable chemical bonds. Therefore, it is unsuitable for utilizing the radicals generated on the substrate surface. For example, the radical Si· forms a stable Si-O bond with an activated oxygen atom, and the radical Si-CH2· forms a Si-CH2-C bond with an activated carbon atom. Consequently, the gases used in conventional plasma treatments reduced the radicals generated on the substrate surface.

[0021] Based on the bonding mechanisms and problems of such conventional plasma treatments, the inventors aimed for a reaction system that utilizes radicals generated on the substrate surface to react with hydrophilic polymers, and investigated various plasma treatment conditions. As a result, when a substrate containing an alkyl group-containing polysiloxane structure is plasma treated with an inert gas such as nitrogen, Si-C is formed on the substrate surface. n H 2n We discovered that radicals containing the compound are formed, these radicals undergo radical transition to the hydrophilic polymer, and the hydrophilic polymer can be efficiently bonded to the substrate surface through the radicals generated on the hydrophilic polymer. We confirmed that the resulting coating layer can achieve sufficient hydrophilicity with a single layer, leading to the present invention.

[0022] In other words, the present invention provides a method for manufacturing soft eye lenses and soft eye lenses.

[0023] [1] An ophthalmic lens substrate comprising a (co)polymer having an alkyl group-containing polysiloxane structure, The substrate surface includes a single coating layer containing a hydrophilic polymer, A soft eye lens in which the water contact angle of the surface of the coating layer is 70° or less. [2] Si in XPS measurement 2pThe soft ophthalmic lens described in [1], wherein the total width at half maximum of the peak derived from is 2.1 eV or less. [3] Si in XPS measurement 2p The soft ophthalmic lens described in [1], wherein more than 60% of the peaks originating from are bonded to two oxygen atoms and two carbon atoms. [4] A soft ophthalmic lens according to any one of [1] to [3], wherein adsorbed water is confirmed on the surface of the coating layer by XPS analysis under a water vapor pressure of 5 mbar. [5] The soft ophthalmic lens according to any one of [1] to [4], wherein the water contact angle of the surface of the coating layer is 60° or less than 50°.

[0024] [6] The soft eye lens according to any one of [1] to [5], wherein the water contact angle after 20 rub tests on the surface of the coating layer is 70° or less.

[0025] [7] The soft eye lens according to [6], wherein the water contact angle of the surface of the coating layer after 20 rub tests is 60° or less. [8] The water contact angle of the coating layer surface after 200 rub tests is 50° or less, as described in any of [1] to [5].

[0026] [9] The coating layer has a thickness of 1 nm to 5 μm, and is a soft ophthalmic lens according to any one of [1] to [8].

[0027]

[10] The soft ophthalmic lens according to any one of [1] to [9], wherein the substrate and the hydrophilic polymer are bonded at least via a CC bond between the Si-C of the substrate and the C of the hydrophilic polymer.

[11] The soft ophthalmic lens according to any one of [1] to

[10] , wherein the substrate and the hydrophilic polymer are further bonded via an OC bond between the Si-alkylene-OO of the substrate and the C of the hydrophilic polymer.

[0028]

[12] The soft ophthalmic lens according to

[10] or

[11] , wherein the substrate and the hydrophilic polymer are further bonded via a Si-C bond between the Si of the substrate and the C of the hydrophilic polymer.

[0029]

[13] A soft ophthalmic lens according to any one of

[10] to

[12] , wherein 5% or more of the alkyl group-containing polysiloxane units present on the surface of the substrate are bonded to the C of the hydrophilic polymer.

[0030]

[14] A soft ophthalmic lens according to

[12] or

[13] , wherein 10% or more of the alkyl group-containing polysiloxane units present on the surface of the substrate are bonded to the C of the hydrophilic polymer.

[0031]

[15] The hydrophilic polymer is water-soluble and has atoms having non-covalent pairs or double bonds, wherein carbon adjacent to the atoms having non-covalent pairs or double bonds is bonded to the Si, Si-C carbon or Si-alkylene-OO oxygen of the substrate, as described in any one of [1] to

[14] .

[0032]

[16] The soft ophthalmic lens according to any one of [1] to

[15] , wherein the substrate is obtained by polymerizing a (macro) monomer composition containing 20% ​​by mass or more of alkyl group-containing polysiloxane.

[0033]

[17] The soft ophthalmic lens according to

[16] , wherein the base material is obtained by polymerizing a (macro) monomer composition containing 30% by mass or more of an alkyl group-containing polysiloxane.

[0034]

[18] The (co)polymer having the alkyl group-containing polysiloxane structure is obtained by polymerizing a (macro) monomer containing an alkylsiloxane having two or more polymerizable reactive groups, as described in any one of [1] to

[17] .

[0035]

[19] The soft ophthalmic lens according to

[18] , wherein the substrate is obtained by polymerizing a (macro)monomer composition comprising an alkylsiloxane having two or more polymerizable reactive groups and optionally at least one selected from an alkylsiloxane having one polymerizable reactive group, a fluoroalkyl (meth)acrylate, an alkyl (meth)acrylate, and a dialkylaminoalkyl (meth)acrylate.

[0036]

[20] The soft ophthalmic lens according to

[19] , wherein the (macro) monomer composition contains 20 to 50% by mass of an alkylsiloxane having two or more polymerizable reactive groups and an alkylsiloxane having one polymerizable reactive group, and contains 30 to 65% by mass of the fluoroalkyl (meth)acrylate.

[0037]

[21] The polymerizable reactive group is a (meth)acrylate group, as described in any one of

[18] to

[20] , for use with soft ophthalmic lenses.

[0038]

[22] A soft ophthalmic lens according to any one of [1] to

[21] , wherein the polysiloxane units of the (co)polymer present on the surface of the substrate are OC=O bonded to SiOH, Si-CH2-OH, or Si.

[23] The hydrophilic polymer is polyvinylpyrrolidone (PVP), polyacrylamide, or a compound in which the nitrogen atom of polyacrylamide is substituted with an alkyl group (for example, poly(N,N-diethylacrylamide), poly(N,N-dimethylacrylamide), poly(N-isopropylacrylamide, etc.), poly(N-vinylacetamide), poly(N-vinylformaldehyde), poly(N-vinylisobutyric acidamide), polyamide epichlorohydrin, poly(2-oxazoline), poly(2-ethyl-2-oxazoline), polyacrylic acid, compounds having a hydrophilic group (e.g., hydroxyethyl group, etc.) on the oxygen atom of polyacrylic acid (e.g., HEMA, etc.), polymethacrylic acid, polylysine, polymaleic acid, alginic acid, chondroitin sulfate, pectin , hyaluronic acid, chitosan, colomic acid, pullulan, dextran, cellulose, polyethylene glycol (PEG), PEG-containing block copolymers (e.g., PEG and polyacrylic acid block copolymer, PEG and polyamino acid block copolymer such as polylactic acid, etc.), PEG-containing surfactants (such as PEG having a long-chain alkyl group at one end), polymers in which the ends of PEG are modified (e.g., PEG having a methyl group, ethyl group, benzyl group, dibenzylpropyl group, dimethylaminoethyl group, etc. at the end), A soft ophthalmic lens according to any one of [1] to

[22] , comprising at least one selected from the group consisting of riphosphorylcholine, polytetrahydrofuran, polyvinyl alcohol, polymethylvinyl ether, polyethyleneimine (PEI), polyallylamine, polydiallylamine, polymethyldiallylamine, poly(N-vinylamine), poly(vinyl-N-methylpyridinium salt), polyvinyl phosphate, polyvinyl sulfonic acid, polystyrene sulfonic acid, polystyrene sulfonate, poly(3-sulfopropyl potassium methacrylate), hydroxyethylcellulose, hydroxypropyl methylcellulose, polydimethyldiallylammonium salt, poly(vinyl methacrylic acid), poly(2-vinylpyridine-N-oxide), and copolymers obtained by crosslinking two or more of these hydrophilic polymers (e.g., ethylene glycol crosslinked polymer of polyacrylic acid (e.g., CLPAH-100)), and hydrophilic (co)polymers having these hydrophilic polymers as a branched structure (e.g., PEG derivatives in which at least one of these hydrophilic polymers is bonded to PEG as a branched structure).

[0039]

[24] The hydrophilic polymer comprises polyvinylpyrrolidone, polyacrylic acid, ethylene glycol crosslinked polymer of polyacrylic acid, starch graft of polyacrylic acid, PEG, PEG-containing block copolymer, alginic acid, chondroitin sulfate, hyaluronic acid, pectin, hydroxyethyl cellulose, dextran, polyvinyl alcohol, polyethyleneimine, polyglutamic acid, or polyacrylamide, as described in

[23] .

[0040]

[25] The hydrophilic polymer comprises polyvinylpyrrolidone, an ethylene glycol crosslinked polymer of polyacrylic acid, polyacrylic acid, chondroitin sulfate, hydroxyethyl cellulose, polyvinyl alcohol, a block copolymer containing PEG, or PEG, as described in

[24] .

[0041]

[26] A soft ophthalmic lens having an oxygen permeability (Dk value) of 150 or more, as described in any one of items [1] to

[25] .

[27] A step of subjecting an ophthalmic lens substrate containing an alkyl group-containing polysiloxane structure to plasma treatment in an inert gas atmosphere to form radicals on the surface of the substrate, The process involves immersing the substrate in an aqueous solution of a hydrophilic polymer containing a structure capable of resonating with radicals on carbon atoms to form a coating layer containing the hydrophilic polymer. A method for manufacturing soft ophthalmic lenses, including [the specified component].

[0042]

[28] The method according to

[27] , wherein the radical comprises a Si· radical and a Si-alkyl· radical.

[0043]

[29] The method according to

[28] , wherein the radical further comprises a Si-alkylene-OO· radical.

[0044]

[30] The method according to any one of

[27] to

[29] , wherein immediately after the plasma treatment, at least 10% or more of the C bonded to Si present on the substrate surface are radicals.

[0045]

[31] The method according to

[30] , wherein immediately after the plasma treatment, at least 15% or more of the Si and C bonded to Si present on the substrate surface are radicals.

[32] The method according to any one of

[27] to

[31] , wherein at least 20% of the alkyl group-containing polysiloxane units present on the substrate surface immediately after the plasma treatment are radicals.

[33] The method according to any one of

[27] to

[32] , wherein the plasma is generated at a low frequency of 50 Hz or 60 kHz and a power of 10 to 150 W.

[0046]

[34] The method according to

[33] , wherein the inert gas is introduced into the reaction chamber at a gas pressure of 2 Pa to 30 Pa and a rate of 1 sccm to 100 sccm.

[0047]

[35] The method according to

[33] or

[34] , wherein the plasma treatment is performed for 5 seconds to 2 minutes.

[36] The method according to

[35] , wherein the plasma is generated with a power of 60 to 150 W, and the plasma treatment is performed for 50 seconds to 2 minutes.

[0048]

[37] The method according to any one of

[27] to

[32] , wherein the plasma is generated by glow discharge at 3 to 30 mA.

[38] The method according to any one of

[27] to

[37] , wherein the inert gas is N2 gas or Ar gas.

[0049]

[39] The method according to any one of

[27] to

[38] , wherein the substrate is obtained by polymerizing a (macro) monomer composition containing 20% ​​by mass or more of alkyl group-containing polysiloxane.

[0050]

[40] The method according to

[39] , wherein the base material is obtained by polymerizing a (macro) monomer composition containing 30% by mass or more of alkyl group-containing polysiloxane.

[0051]

[41] The (co)polymer having the alkyl group-containing polysiloxane structure is obtained by polymerizing a (macro) monomer containing an alkylsiloxane having two or more polymerizable reactive groups, according to any one of

[27] to

[40] .

[0052]

[42] The method according to

[41] , wherein the substrate is obtained by polymerizing a (macro) monomer composition comprising an alkylsiloxane having two or more polymerizable reactive groups and optionally at least one selected from an alkylsiloxane having one polymerizable reactive group, a fluoroalkyl (meth)acrylate, an alkyl (meth)acrylate, and a dialkylaminoalkyl (meth)acrylate.

[0053]

[43] The method according to

[42] , wherein the (macro) monomer composition contains 20 to 50% by mass of an alkylsiloxane having two or more polymerizable reactive groups and an alkylsiloxane having one polymerizable reactive group, and the fluoroalkyl (meth)acrylate contains 30 to 65% by mass.

[0054]

[44] The method according to any one of

[41] to

[43] , wherein the polymerizable reactive group is a (meth)acrylate group.

[0055]

[45] The hydrophilic polymer is water-soluble and has an alkyl group and / or an alkylene group and / or a methine group and an atom or double bond having a lone pair of electrons, wherein the carbon of the alkyl group, alkylene group or methine group is adjacent to the atom or double bond having a lone pair of electrons. The method according to any one of

[27] to

[44] .

[0056]

[46] The hydrophilic polymer is polyvinylpyrrolidone (PVP), polyacrylamide, or a compound in which the nitrogen atom of polyacrylamide is substituted with an alkyl group (for example, poly(N,N-diethylacrylamide), poly(N,N-dimethylacrylamide), poly(N-isopropylacrylamide, etc.), poly(N-vinylacetamide), poly(N-vinylformaldehyde), poly(N-vinylisobutyric acidamide), polyamide epichlorohydrin, poly(2-oxazoline), poly(2-ethyl-2-oxazoline), polyacrylic acid, compounds having a hydrophilic group (e.g., hydroxyethyl group) on the oxygen atom of polyacrylic acid (e.g., HEMA), polymethacrylic acid, polylysine, polymaleic acid, alginic acid, chondroitin sulfate, pector Chin, hyaluronic acid, chitosan, colomic acid, pullulan, dextran, cellulose, polyethylene glycol (PEG), PEG-containing block copolymers (e.g., PEG and polyacrylic acid block copolymer, PEG and polyamino acid block copolymer, etc.), PEG-containing surfactants (e.g., PEG with a long-chain alkyl group at one end), polymers with modified PEG ends (e.g., PEG with a methyl group, ethyl group, benzyl group, dibenzylpropyl group, dimethylaminoethyl group, etc. at the end), etc. The method according to any one of

[27] to

[45] , comprising at least one selected from the group consisting of polyphosphorylcholine, polytetrahydrofuran, polyvinyl alcohol, polymethylvinyl ether, polyethyleneimine (PEI), polyallylamine, polydiallylamine, polymethyldiallylamine, poly(N-vinylamine), poly(vinyl-N-methylpyridinium salt), polyvinyl phosphate, polyvinyl sulfonic acid, polystyrene sulfonic acid, polystyrene sulfonate, poly(3-sulfopropyl potassium methacrylate), hydroxyethylcellulose, hydroxypropyl methylcellulose, polydimethyldiallylammonium salt, poly(vinyl methacrylic acid), poly(2-vinylpyridine-N-oxide), and copolymers obtained by crosslinking two or more of these hydrophilic polymers (e.g., ethylene glycol crosslinked polymer of polyacrylic acid (e.g., CLPAH-100)) and hydrophilic (co)polymers having these hydrophilic polymers as branched structures (e.g., PEG derivatives in which at least one of these hydrophilic polymers is bonded to PEG as a branched structure).

[0057]

[47] The hydrophilic polymer comprises polyvinylpyrrolidone, polyacrylic acid, ethylene glycol crosslinked polymer of polyacrylic acid, starch graft of polyacrylic acid, PEG, PEG-containing block copolymer, alginic acid, chondroitin sulfate, hyaluronic acid, pectin, hydroxyethyl cellulose, dextran, polyvinyl alcohol, polyethyleneimine, polyglutamic acid, or polyacrylamide, according to

[46] .

[48] ​​The hydrophilic polymer comprises polyvinylpyrrolidone, an ethylene glycol crosslinked polymer of polyacrylic acid, polyacrylic acid, chondroitin sulfate, hydroxyethyl cellulose, polyvinyl alcohol, a block copolymer comprising PEG, or the method according to

[47] .

[0058]

[49] The method according to any one of

[27] to

[48] , wherein the substrate that has undergone plasma treatment is kept in an oxygen-containing atmosphere for a short time (preferably within 10 seconds).

[0059]

[50] The method according to

[49] , wherein the oxygen concentration of the oxygen-containing atmosphere is 0.5 to 20% by mass.

[0060]

[51] The method according to

[50] , wherein the oxygen concentration of the oxygen-containing atmosphere is 0.8 to 10% by mass.

[0061]

[52] The method according to any one of

[27] to

[51] , wherein the substrate on which the radicals are formed is immersed in an aqueous solution of the hydrophilic polymer within 10 seconds after the plasma treatment.

[0062]

[53] The method according to any one of

[27] to

[52] , wherein the substrate on which the radicals are formed is immersed in an aqueous solution of the hydrophilic polymer at a temperature of 5 to 135°C for 20 minutes to 2 hours.

[54] The method according to

[53] , wherein the substrate on which the radicals have been formed is immersed in an aqueous solution of the hydrophilic polymer at a temperature of 10 to 30°C for 30 minutes to 1 hour, and then heated at a temperature of 80 to 135°C for 20 minutes to 2 hours.

[0063]

[55] The concentration of the hydrophilic polymer in the aqueous solution is 0.01% by mass to 1% by mass, and the method according to any one of

[27] to

[54] .

[56] After the immersion, heat treatment is performed in water or a buffer solution, and the method according to any one of

[27] to

[55] .

[57] The heat treatment is performed in a lens storage solution at a temperature of 80 to 135°C for 20 minutes to 2 hours, and the method according to

[56] .

[0064]

[58] The coating layer has a thickness of 1 nm to 5 μm, and the method according to any one of

[27] to

[57] .

[0065]

[59] A soft contact lens produced by the method according to any one of

[27] to

[58] .

[0066] As described above, in the present invention, without using a gas containing a carbon atom or an oxygen atom, a substrate containing a (co)polymer having a hydrocarbon group, preferably an alkyl group-containing polysiloxane structure, is plasma-treated in an inert gas atmosphere to activate the substrate surface. When activated by plasma, a compound having an alkyl group-containing polysiloxane structure generates Si· radicals and Si-C n H 2n · radicals (typically Si-CH2· radicals), but when plasma is formed using a gas containing oxygen or carbon, active species of oxygen or carbon form stable chemical bonds with the radicals on the substrate surface. That is, Si· radicals form stable Si-O bonds with oxygen, and Si-C n H 2n · radicals form Si-C n H 2n -C, so that the radicals on the substrate surface decrease. On the other hand, when a (co)polymer having an alkyl group-containing polysiloxane structure is plasma-treated in an inert gas atmosphere, since the inert gas does not react with the radicals, the concentration of Si· radicals and Si-C n H 2n · radicals on the substrate surface increases. When such a substrate is immersed in an aqueous solution of a hydrophilic polymer, the radicals on the substrate surface, particularly Si-Cn H 2n Radicals are transferred to the hydrophilic polymer, generating radicals in the hydrophilic polymer. As a result, recombination of radicals occurs between the substrate and the hydrophilic polymer, thereby bonding the substrate and the hydrophilic polymer. When plasma treatment is performed with a gas containing oxygen or carbon, the bonding frequency between the substrate and the hydrophilic polymer is low, making it impossible to achieve sufficient hydrophilization. However, in the method according to the present invention, which utilizes the numerous radicals generated in the substrate and the hydrophilic polymer to bond them together, the bonding frequency between the substrate and the hydrophilic polymer is high, and sufficient hydrophilization can be achieved with a single plasma treatment. [Brief explanation of the drawing]

[0067] [Figure 1] Figure 1 is a conceptual diagram schematically showing the structure near the surface of a lens according to one embodiment of the present invention. [Figure 2] The spectrum of the O1S region obtained by XPS analysis of the sample from Example 1 is shown. [Figure 3] The spectrum of the C1S region obtained by XPS analysis of the sample from Example 1 is shown. [Figure 4] The spectrum of the C1S region obtained by XPS analysis of the sample from Example 2 is shown. [Figure 5] The spectrum of the Si2p region obtained by XPS analysis of the sample from Synthesis Example 1 is shown. [Figure 6] The spectrum of the Si2p region obtained by XPS analysis after plasma treatment of the sample from Synthesis Example 1 is shown. [Figure 7] The spectrum of the Si2p region obtained by XPS analysis of the sample from Example 1 is shown. [Figure 8] The spectrum of the Si2p region obtained by XPS analysis of the sample from Reference Example 1 is shown. [Figure 9] The spectrum of the O1S region obtained by XPS analysis of the sample from Example 3 is shown. [Figure 10] The spectrum of the C1s region obtained by XPS analysis of the substrate after plasma treatment in Example 3 is shown. [Figure 11]The spectrum of the C1s region obtained by XPS analysis of the sample from Example 3 is shown. [Modes for carrying out the invention]

[0068] Embodiments of the present invention will be described in detail. However, the present invention should not be understood as being limited to the following embodiments. In this specification, the term "(macro)monomer" means macromonomer and / or monomer. Similarly, the term "(meth)acryloyl" means methacryloyl and / or acryloyl, and terms such as (meth)acrylic and (meth)acrylate are used in the same manner. Likewise, the term "(co)polymer" means copolymer or polymer. In this specification, "Si-alkyl radical" is defined as "Si-C n H 2n It is synonymous with "Si-C radical" and is sometimes abbreviated as "Si-C radical". Similarly, in this specification, "Si-alkylene-OO radical" is synonymous with "Si-C n H 2n It is synonymous with "-OO radical" and is sometimes abbreviated as "Si-COO radical".

[0069] The present invention relates to a method for manufacturing a soft ophthalmic lens, which involves subjecting an ophthalmic lens substrate containing a polymer capable of forming radicals by plasma treatment in an inert gas atmosphere to form radicals on the substrate surface, and then immersing the substrate with these radicals in an aqueous solution of a hydrophilic polymer to induce a radical transition to the hydrophilic polymer, thereby forming a hydrophilic polymer coating layer. The soft ophthalmic lens of the present invention is a lens obtained by such a method, and although it includes a coating layer containing a hydrophilic polymer on the surface of the substrate, it exhibits high hydrophilicity with a single coating layer. The details will be described below.

[0070] 1. Base material The substrate used in the ophthalmic soft lens of the present invention contains a polymer capable of forming silicon or carbon radicals by an inert gas plasma. Such a polymer is usually composed of silicon, oxygen, carbon, and hydrogen, and is preferably a (co)polymer having an alkyl group-containing polysiloxane structure, and more preferably a (co)polymer having the structural unit shown in the following formula (1). [ka] (In formula (1), R1 and R2 independently represent an alkyl group or a hydrogen atom, and may differ from one structural unit to another, or may be the same in some or all structural units. However, at least one R1 or R2 is a hydrocarbon group. n represents an integer of 2 or more.)

[0071] As for the alkyl group, in order to reduce the water repellency and hydrophobicity of the substrate itself, alkyl groups with 10 or fewer carbon atoms are preferred, alkyl groups with 1 to 5 carbon atoms are more preferred, and alkyl groups with 1 to 3 carbon atoms are even more preferred. On the other hand, in order to form many radicals on the substrate by plasma treatment, it is preferable that at least one of R1 and R2 in each siloxane unit shown in formula (1) is an alkyl group. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, t-butyl, and decyl groups, with methyl, ethyl, propyl, and isopropyl groups being preferred, methyl and ethyl groups being more preferred, and methyl groups being the most preferred.

[0072] n represents the number of structural units shown in formula (1), and is usually in the range of 2 to 1500, preferably 80 or more, and more preferably 100 or more. In particular, 100 to 1400 is preferred, 120 to 950 is more preferred, and 130 to 700 is even more preferred.

[0073] The (co)polymer having the alkyl group-containing polysiloxane structure described above is usually obtained by polymerizing a polysiloxane compound having multiple polymerizable functional groups and one or more alkyl groups per molecule (hereinafter abbreviated as component A), or by polymerizing component A with another polymerizable compound (hereinafter abbreviated as component B).

[0074] The polymerizable functional group of component A is preferably a radically polymerizable functional group, and more preferably a group having a carbon-carbon double bond. Examples of preferred polymerizable functional groups include vinyl groups, allyl groups, (meth)acryloyl groups, α-alkoxymethylacryloyl groups, maleic acid residues, fumaric acid residues, itaconic acid residues, crotonic acid residues, isocrotonic acid residues, and citraconic acid residues. Among these, the (meth)acryloyl group is particularly preferred due to its high polymerizability.

[0075] The alkyl group of component A can be an alkyl group similar to the alkyl group of the structural unit shown in formula (1), and the preferred alkyl group is also similar.

[0076] The weight-average molecular weight of component A is preferably 6,000 or more, more preferably in the range of 9,000 to 160,000, and even more preferably in the range of 10,000 to 70,000. The dispersion of component A (value obtained by dividing the weight-average molecular weight by the number-average molecular weight) is preferably 6 or less, more preferably 3 or less, even more preferably 2 or less, and particularly preferably 1.5 or less. In this specification, the number-average molecular weight, weight-average molecular weight, and dispersion of component A are the number-average molecular weight in polystyrene terms, measured by gel permeation chromatography (GPC) using chloroform as the solvent.

[0077] Component B includes polysiloxane compounds having one or more hydrocarbon groups and one polymerizable functional group per molecule (usually located at one end) (hereinafter abbreviated as Component B1), hydrophobic (meth)acrylates having one or more polymerizable functional groups but lacking a siloxane structure (hereinafter abbreviated as Component B2), hydrophilic (meth)acrylates having one or more polymerizable functional groups but lacking a siloxane structure (hereinafter abbreviated as Component B3), and other monomers (hereinafter abbreviated as Component B4).

[0078] The polymerizable functional groups of component B1 are the same as those of component A. Preferred polymerizable functional groups include vinyl groups, allyl groups, (meth)acryloyl groups, α-alkoxymethylacryloyl groups, maleic acid residues, fumaric acid residues, itaconic acid residues, crotonic acid residues, isocrotonic acid residues, and citraconic acid residues, with (meth)acryloyl groups being particularly preferred.

[0079] The alkyl group of component B1 is similar to that of component A, and the alkyl group of the structural unit shown in formula (1) is also a preferred alkyl group.

[0080] The weight-average molecular weight of component B1 is preferably 2,000 or more, more preferably in the range of 2,000 to 70,000, and even more preferably in the range of 5,000 to 10,000. Similarly, the degree of dispersion of component B1 is preferably 6 or less, more preferably 3 or less, even more preferably 2 or less, and particularly preferably 1.5 or less, similar to component A.

[0081] As demonstrated in the examples described later, the plasma treatment according to the present invention generates Si-alkyl radicals in the alkyl-containing polysiloxane described above, transfers these radicals to a hydrophilic polymer, and hydrophilizes the substrate surface through bonding between the alkyl-containing polysiloxane and the hydrophilic polymer. Therefore, the substrate of the present invention may be composed of a (co)polymer obtained by polymerizing a composition containing component A and optionally component B1. Furthermore, as demonstrated in Reference Example 2 described later, polymers of components A and B1 are localized on the substrate surface, and the amount of radicals generated by the plasma treatment is not significantly affected by the content of these components, and sufficient hydrophilization is possible even with relatively low content. For this reason, the content of components A and B1 in the composition may be 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more. On the other hand, the content of these components is preferably determined by considering the content of other monomer components necessary to impart other properties, along with the required oxygen permeability. From this perspective, it is usually 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0082] Examples of component B2 include fluoroalkyl (meth)acrylates, alkyl (meth)acrylates, dialkylaminoalkyl (meth)acrylates, glycol (meth)acrylates, (meth)acrylates having an aryl group, (meth)acrylates having other additional double bonds, and other (meth)acrylates.

[0083] As the (meth)acrylate having a fluoroalkyl group, a (meth)acrylate having a fluoroalkyl group with 1 to 20 carbon atoms is preferred, and a (meth)acrylate having a fluoroalkyl group with 1 to 10 carbon atoms is more preferred.

[0084] The (meth)acrylate having a fluoroalkyl group may be one type or a combination of two or more types. The content of the (meth)acrylate having a fluoroalkyl group can be 0 to 80% by mass in the (macro)monomer composition, preferably 10 to 75% by mass, more preferably 20 to 70% by mass, and more preferably 30 to 65% by mass.

[0085] As the alkyl (meth)acrylate, a (meth)acrylate having an alkyl group with 1 to 20 carbon atoms is preferred, and a (meth)acrylate having an alkyl group with 5 to 15 carbon atoms is more preferred.

[0086] Alkyl (meth)acrylate may be present in one type or in a combination of two or more types. The alkyl (meth)acrylate content in the (macro) monomer composition can be 0 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 10% by mass.

[0087] As the dialkylaminoalkyl (meth)acrylate, a (meth)acrylate having a dialkylaminoalkyl group with 3 to 20 carbon atoms is preferred, and a (meth)acrylate having an alkyl group with 4 to 10 carbon atoms is more preferred.

[0088] As the glycol (meth)acrylate, a (meth)acrylate having an alkylene glycol or alkoxydialkylene glycol having 3 to 20 carbon atoms is preferred, and a (meth)acrylate having an alkylene glycol or alkoxydialkylene glycol having 5 to 10 carbon atoms is more preferred.

[0089] Preferred (meth)acrylates having an aryl group include monocyclic or bicyclic aryl groups with 5 to 12 carbon atoms, such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, and bisphenol A dimethacrylate. Other (meth)acrylates having additional double bonds include vinyl groups, allyl groups, maleic acid residues, fumaric acid residues, itaconic acid residues, crotonic acid residues, isocrotonic acid residues, or citraconic acid residues, with vinyl methacrylate being preferred. Other (meth)acrylates include trimethylolpropane trimethacrylate and pentaerythritol tetramethacrylate.

[0090] The content of glycol (meth)acrylate, (meth)acrylate having an aryl group, (meth)acrylate having other additional double bonds, and other (meth)acrylates is usually 30% by mass or less, preferably 20% by mass or less, in the (macro)monomer composition.

[0091] Examples of component B3 include methacrylic acid, acrylic acid, itaconic acid, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, glycerol methacrylate, polyethylene glycol methacrylate, etc.

[0092] Examples of component B4 include monomers having a vinyl group, an allyl group, a maleic acid residue, a fumaric acid residue, an itaconic acid residue, a crotonic acid residue, an isocrotonic acid residue, or a citraconic acid residue, or monomers in which these polymerizable reactive groups are bonded to an amide, with monomers having a vinyl group and monomers having an amide-bonded polymerizable reactive group being preferred.

[0093] The content of components B3 and B4 can be independently 0 to 50% by mass in the (macro)monomer composition, depending on the intended use of each monomer, and preferably 1 to 40% by mass. Details of (co)polymers having an alkyl group-containing polysiloxane structure and their manufacturing methods are described in Patent Documents 2, 3, 5, 8, 11, and 16, etc., and their contents are incorporated herein by reference.

[0094] The base material may contain other components such as UV absorbers, dyes, colorants, wetting agents, slip agents, pharmaceutical and nutritional supplements, compatibilizers, antimicrobial components, and mold release agents. These components may be present in either a non-reactive or copolymerized form. For example, if a UV absorber is included, it can protect the wearer's eyes from harmful ultraviolet radiation. If a colorant is included, the lens becomes colored, making it easier to identify and improving handling convenience.

[0095] When an ultraviolet absorber is included, its content is 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, and even more preferably 0.1 to 2 parts by weight, per 100 parts by weight of component A. When a coloring agent is included, its content is 0.00001 to 5 parts by weight, more preferably 0.0001 to 1 part by weight, and even more preferably 0.0001 to 0.5 parts by weight, per 100 parts by weight of component A.

[0096] (Macro)monomer compositions may contain any solvent to improve the compatibility of each component. The mass percentage of each component in the composition mentioned above indicates the content in a composition consisting solely of (macro)monomers. The solvent is not particularly limited, but tertiary alcohols or saturated carboxylic acids are preferably used.

[0097] In polymerization, a thermal polymerization initiator or a photopolymerization initiator can be used as needed. Azo compounds or peroxides are preferred as thermal polymerization initiators. Various benzoin derivatives are examples of photopolymerization initiators.

[0098] Known methods can be used to polymerize (macro) monomers and form a substrate. For example, methods such as obtaining a polymer in the form of a round bar or plate and processing it into a desired shape by cutting, mold polymerization, and spin-cast polymerization can be used.

[0099] 2. Plasma treatment In this invention, a substrate containing a (co)polymer having an alkyl group-containing polysiloxane structure is plasma-treated in an inert gas atmosphere without using gases containing carbon atoms or oxygen atoms. When the alkyl group-containing polysiloxane structure is activated by plasma, Si radicals and Si-alkyl(C) radicals are produced. n H 2n Although radicals are generated, the use of an inert gas prevents the radicals on the substrate surface from being stabilized by reactive species such as oxygen and carbon. As a result, the radicals generated on the substrate surface are transferred to the hydrophilic polymer, and the hydrophilic polymer can be efficiently bonded to the substrate surface through the recombination of these radicals.

[0100] In alkyl-containing polysiloxane compounds, irradiating with a low-intensity plasma for a short time generates Si radicals and Si-C n H 2n While radicals can be formed, if the plasma intensity is high or the irradiation time is long, amorphous silicon monoxide is more likely to be produced, and when removed from the device, this may oxidize into glassy silicon dioxide (Non-Patent Literature 4). Also, among the generated radicals, Si-C n H 2nRadicals are most likely to cause radical transfer to hydrophilic polymers (Non-Patent Literature 4). For this reason, it is preferable to perform plasma treatment under mild conditions in order to form a large number of radicals on the substrate surface and cause more radical transfer to hydrophilic polymers. On the other hand, if conditions are set to easily generate Si radicals, crosslinking by condensation of silanol groups becomes easier between alkyl group-containing polysiloxane compounds. If a hydrophilic polymer is present nearby during this condensation, the hydrophilic polymer is involved in the condensation reaction and becomes entangled with the alkyl group-containing polysiloxane compound, and this structure improves resistance to abrasion. Therefore, it is preferable to set plasma treatment conditions from this viewpoint as well.

[0101] As an inert gas, N 2、 Ar, He 、 Ne is available, with N2 being preferred. He has a small atomic weight and can generate a stable plasma with low power. However, it is a rare gas and therefore expensive. The same applies to Ne. Ar is relatively abundant in air, but it does not necessarily have an advantage over N2.

[0102] Low-frequency discharge and glow discharge are preferred methods for generating plasma. Low-frequency discharge is preferably 10kHz to 10Hz, more preferably 1kHz or below, and even more preferably 100Hz or below. For such low-frequency discharge, 50Hz or 60Hz discharges that can utilize commercial power are convenient.

[0103] The power should preferably be varied depending on the size of the electrodes, but it is usually in the range of 10 to 150 W, more preferably in the range of 60 to 120 W, and particularly preferably in the range of 70 to 100 W. For parallel plate electrodes with a diameter of about 10 cm, 20 to 100 W is preferred, and more preferably in the range of 30 to 80 W. For parallel plate electrodes with a diameter of 20 cm, 40 to 150 W is preferred, more preferably in the range of 60 to 120 W, and particularly preferably in the range of 70 to 100 W.

[0104] The plasma irradiation time is preferably determined according to the introduction and exhaust rates of the inert gas, as described later, but is usually set between 5 seconds and 2 minutes. From the viewpoint of improving hydrophilicity, production efficiency, and introducing silanol group condensation reactions between alkyl group-containing polysiloxane compounds, a time between 20 seconds and 1 minute 30 seconds is preferred, and 20 seconds to 1 minute is more preferred.

[0105] In glow discharge, it is preferable to generate plasma with a voltage of 300-800V and a current of 3-30mA. In glow discharge, the plasma irradiation time can usually be set between 1 second and 1 minute, preferably between 3 and 20 seconds, and more preferably between 7 and 15 seconds.

[0106] As the introduction and exhaust rates of the inert gas increase, the proportion of inert gas to the plasma increases, the gas temperature decreases, and the plasma concentration decreases. Therefore, the plasma intensity also depends on the introduction and exhaust rates of the inert gas, and the plasma intensity can be lowered by increasing these rates. It is preferable to determine these rates according to the plasma irradiation time. If the gas introduction rate is too fast, the spatial intensity of the plasma may become unbalanced, but N 2、 Ar, He 、 In inert gases such as Ne, this effect is small because the diffusion rate is high. The introduction and exhaust rates of the inert gas can be explained by the pressure and introduction rate of the inert gas during plasma generation, and can be used as indicators to replace the introduction and exhaust rates of the inert gas. From these points of view, the pressure of the inert gas is preferably determined in the range of 1 Pa to 50 Pa, more preferably in the range of 2 Pa to 30 Pa, and even more preferably in the range of 5 Pa to 25 Pa, depending on the plasma irradiation time. Furthermore, the introduction rate of the inert gas is preferably in the range of 1 sccm to 100 sccm, more preferably in the range of 3 sccm to 50 sccm, and even more preferably in the range of 5 sccm to 30 sccm.

[0107] Plasma treatment in an inert gas atmosphere according to the present invention can form many radicals on the substrate surface. More specifically, immediately after plasma treatment, radicals can be formed in at least 20% of the alkyl group-containing polysiloxane units present on the substrate surface. In particular, when the substrate is exposed to an inert gas plasma under the mild conditions described above, more than 14% of the Si atoms in the alkyl group-containing siloxane units present on the substrate surface can be converted into Si- radicals. In addition, more than 11% of the alkyl groups (e.g., methyl groups) in the alkyl group-containing siloxane units present on the surface of the compound can be converted into Si-C radicals. n H 2n • It can be converted into radicals. Therefore, when the alkyl group-containing siloxane unit has two alkyl groups, by selecting preferred plasma treatment conditions, radicals can be formed in more than 36% of the alkyl group-containing siloxane units present on the substrate surface, and many of these can be used for bonding with hydrophilic polymers, as described later. Here, "X of alkyl-containing siloxane units present on the surface" refers to X (e.g., Si atoms or methyl groups) that can be measured when the substrate is XPS analyzed at a water vapor pressure of 5 mbar using an XPS instrument such as EnviroESCA. The detector angle is 70°, and the XPS detection depth in this case is approximately 5 nm.

[0108] The soft ophthalmic lenses obtained by the mild plasma treatment conditions described above showed that in XPS measurements in the Si region, Si 2p The peak is sharp, and the full width at half maximum is less than 2.1 eV. This indicates that the oxidation of Si atoms in alkyl-containing siloxane units present on the surface is limited. 2p When the peaks are curve-fitted for each oxidation state, more than 60% of the Si atoms present on the surface are bonded to two O atoms, indicating that oxidation has not progressed from the original PDMS state. Thus, it has the characteristic of being able to form many radicals on the substrate surface while suppressing the oxidation of alkyl group-containing siloxanes.

[0109] When the substrate is placed in an oxygen-containing atmosphere after plasma treatment, Si-C n H 2n • Radicals react with oxygen to irreversibly form Si-C n H 2n -OO· radicals are formed. These radicals are stable for several minutes and abstract hydrogens from hydrophilic polymers that readily form radicals, causing a radical transition. These radicals can also be used to recombine with radicals of hydrophilic polymers to bond the hydrophilic polymers to the substrate (Non-Patent Documents 5 and 6). On the other hand, Si· radicals also react with oxygen to irreversibly form Si-OO· radicals, which cause radical transition to hydrophilic polymers and combine with hydrophilic polymers to form Si-OO-R (where R represents the hydrocarbon of the hydrophilic polymer). However, this structure is unstable and eventually dissociates to form Si-OH (Non-Patent Literature 5). Also, Si-C n H 2n When radicals are exposed to oxygen for several hours, Si-C n H 2n -OH is converted to OC=O when bonded to Si. [ka] [In the formula, R 3 and R 4 R represents an alkyl group, 5 This represents an alkylene. Preferred alkyl groups are the same as, or corresponding to, R1 and R2 in formula (1).

[0110] Si-C n H 2n The proportion of OH can be 8% or more of the alkyl group (e.g., methyl group) of the alkyl group-containing siloxane unit present on the substrate surface, and OC=O can be 3% or more, giving the substrate surface hydrophilicity. However, if exposed to an oxygen-containing atmosphere in this state, the hydrophobic siloxane portion moves to the surface, and the substrate surface becomes hydrophobic. More specifically, the hydrophilic group of formula (2) above begins to form a few minutes after radical irradiation, and thereafter the substrate surface gradually becomes hydrophobic. Thus, when a substrate treated with plasma is left in an oxygen-containing atmosphere for a long time, the number of radicals that bond hydrophilic polymers to the substrate decreases overall, and the bonding efficiency between the hydrophilic polymer and the substrate decreases, which is undesirable. On the other hand, Si-C n H 2n - In order to more efficiently generate bonding with hydrophilic polymers using OO radicals, it is preferable to expose the substrate to an oxygen-containing atmosphere for a short time after plasma treatment. For example, by exposing the substrate to an oxygen-containing atmosphere for 10 seconds or less, Si-C n H 2n -OO radicals can be used, and it is preferable to expose the substrate to an oxygen-containing atmosphere within 5 seconds, and more preferably within 3 seconds. Also, from a similar viewpoint, if a long time is required before immersion in a hydrophilic polymer solution after plasma treatment, it is preferable to place the substrate in an inert gas atmosphere with an oxygen concentration of 1% by mass or less.

[0111] 3. Hydrophilization treatment using hydrophilic polymers In this invention, the substrate surface is made hydrophilic by immersing the plasma-treated substrate in an aqueous solution of a hydrophilic polymer. More specifically, the plasma treatment brings Si radicals and Si-C onto the surface. n H 2n • Radical and optionally Si-C n H 2n -OO· The substrate on which radicals have been formed is immersed in an aqueous solution of hydrophilic polymer, and the Si-C on the surface of the substrate n H 2n Radicals and, in some cases, SiC n H 2n -OO radicals transfer radicals to the hydrophilic polymer, and the recombination of radicals generated in the substrate and the hydrophilic polymer binds the two together. Therefore, hydrophilic polymers need to be compounds that can have hydrogen extracted by radicals generated on the substrate surface, thereby forming radicals. In this regard, as will be demonstrated in the examples described later, even decane, which is an alkane, can undergo plasma treatment to form Si-C n H 2nIt can bond to alkyl-containing polysiloxane compounds that have formed radicals (typically Si-CH2 radicals). In other words, any compound containing a structure that can resonate with a radical on a carbon atom can be bonded to an alkyl-containing polysiloxane compound according to the present invention, and it does not have to be a hydrophilic polymer.

[0112] Therefore, various hydrophilic polymers can be used as hydrophilic polymers, as long as they contain a structure that can resonate with radicals on carbon atoms. For example, polyvinylpyrrolidone (PVP), polyacrylamide, and compounds in which the nitrogen atom of polyacrylamide is substituted with an alkyl group (for example, an alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms) (for example, poly(N,N-diethylacrylamide), poly(N,N-dimethylacrylamide), poly(N-isopropylacrylamide, etc.), poly(N-vinylacetamide), poly(N-vinylformaldehyde), poly(N-vinylisobutyric acidamide), polyamide epichlorohydrin, poly(2-oxazoline), poly(2-ethyl-2-oxazoline), polyacrylic acid, compounds having a hydrophilic group (e.g., hydroxyethyl group, etc.) on the oxygen atom of polyacrylic acid (e.g., HEMA, etc.), polymethacrylic acid, polylysine, polymaleic acid, alginic acid, Droitin sulfate, pectin, hyaluronic acid, chitosan, colomic acid, pullulan, dextran, cellulose, polyethylene glycol (PEG), PEG-containing block copolymers (e.g., PEG and polyacrylic acid block copolymer, PEG and polyamino acid block copolymer such as polylactic acid, etc.), PEG-containing surfactants (e.g., PEG with a long-chain alkyl group at one end), polymers with modified PEG ends (e.g., methyl group, ethyl group, benzyl group, dibenzylpropyl group, dimethyl group at the end) Examples include PEG having a diaminoethyl group, polyphosphorylcholine, polytetrahydrofuran, polyvinyl alcohol, polymethylvinyl ether, polyethyleneimine (PEI), polyallylamine, polydiallylamine, polymethyldiallylamine, poly(N-vinylamine), poly(vinyl-N-methylpyridinium salt), polyvinyl phosphate, polyvinyl sulfonic acid, polystyrene sulfonic acid, polystyrene sulfonate, poly(3-sulfopropyl potassium methacrylate), hydroxyethylcellulose, hydroxypropyl methylcellulose, polydimethyldiallylammonium salt, poly(vinyl methacrylic acid), poly(2-vinylpyridine-N-oxide), and copolymers obtained by crosslinking two or more of these hydrophilic polymers (e.g., ethylene glycol crosslinked polymer of polyacrylic acid (e.g., CLPAH-100)), and hydrophilic (co)polymers having these hydrophilic polymers as branched structures (e.g., PEG derivatives in which at least one of these hydrophilic polymers is bonded to PEG as a branched structure).

[0113] However, the ease with which radicals generated on the substrate surface are transferred to hydrophilic polymers varies depending on the type of hydrophilic polymer. Furthermore, the reactivity of radicals from the hydrophilic polymer generated by radical transfer with radicals from alkyl-containing polysiloxane compounds varies depending on the type of hydrophilic polymer. Compounds having atoms with lone pairs of electrons (e.g., oxygen, nitrogen) or carbon atoms that can resonate with a double bond (usually the carbon atoms of alkyl and / or alkylene and / or methine groups) are more Si-C n H 2n Compounds that readily react radically with atoms having two lone pairs of electrons (e.g., oxygen, nitrogen) or atoms having lone pairs of electrons (e.g., oxygen, nitrogen) and carbon atoms that are resonant with the double bond are Si-C n H 2n -OO· also undergoes radical transition, and each radical on the substrate (Si·, Si-C) is subjected to radical transition. n H 2n • Si-C n H 2n It reacts with -OO·) and recombines.

[0114] Furthermore, in order for radical transition and recombination to occur, the hydrophilic polymer needs to approach the radicals on the substrate surface. However, if the polymer has a rigid structure, such as when the polymer's main chain contains an aromatic ring, radical transition and recombination may be difficult. Therefore, compounds that do not contain an aromatic ring in the polymer's main chain are preferred. Also, since alkyl group-containing siloxane units are negatively charged, anionic polymers have difficulty approaching the surface. Therefore, compounds that do not contain anionic groups are preferred. However, this problem can be resolved by adjusting the pH and salt concentration of the aqueous solution of the polymer to suppress charge repulsion.

[0115] Therefore, the hydrophilic polymer used in the present invention is preferably selected from these viewpoints, and examples of preferred hydrophilic polymers include, for example, polyvinylpyrrolidone (PVP), polyacrylamide, and compounds in which the nitrogen atom of polyacrylamide is substituted with an alkyl group (for example, an alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms) (for example, poly(N,N-diethylacrylamide), poly(N,N-dimethylacrylamide), poly(N-isopropylacrylamide, etc.), poly(N-vinylacetamide), poly(N-vinylformaldehyde), poly(N-vinylisobutyric acid amide), polyamide epichlorohydrin, poly(2-oxazoline), poly(2-ethyl-2-oxazoline), polyacrylic acid, compounds having a hydrophilic group (e.g., hydroxyethyl group) on the oxygen atom of polyacrylic acid (e.g., HEMA), polymethacrylic acid, polylysine, polymaleic acid, alginic acid, chondroitin sulfate, pectin, hyaluronic acid, chitosan, colomic acid, pullulan, dextran, cellulose, polyethylene glycol (PEG), block copolymers containing PEG (e.g., block copolymer of PEG and polyacrylic acid, block copolymer of PEG and polyamino acids such as polylactic acid, etc.), surfactants containing PEG (e.g., PEG having a long-chain alkyl group at one end), PEG with modified ends Examples include decorated polymers (e.g., PEG having methyl groups, ethyl groups, benzyl groups, dibenzylpropyl groups, dimethylaminoethyl groups, etc. at the terminals), polyphosphorylcholine, polytetrahydrofuran, polyvinyl alcohol, polymethyl vinyl ether, polyethyleneimine (PEI), polyallylamine, polydiallylamine, polymethyldiallylamine, poly(N-vinylamine), poly(vinyl-N-methylpyridinium salt), polyvinyl phosphate, polyvinyl sulfonic acid, polystyrene sulfonic acid, polystyrene sulfonate, poly(3-sulfopropyl potassium methacrylate), hydroxyethylcellulose, hydroxypropyl methylcellulose, and copolymers obtained by crosslinking two or more of these hydrophilic polymers, as well as hydrophilic (co)polymers having these hydrophilic polymers as branched structures (e.g., PEG derivatives in which at least one of these hydrophilic polymers is bonded to PEG as a branched structure).

[0116] From a similar viewpoint, polyvinylpyrrolidone, polyacrylic acid, ethylene glycol crosslinked polymer of polyacrylic acid, starch graft of polyacrylic acid, PEG, PEG-containing block copolymer, alginic acid, chondroitin sulfate, hyaluronic acid, pectin, hydroxyethyl cellulose, dextran, polyvinyl alcohol, polyethyleneimine, polyglutamic acid, or polyacrylamide are more preferred, and polyvinylpyrrolidone, ethylene glycol crosslinked polymer of polyacrylic acid, polyacrylic acid, chondroitin sulfate, hydroxyethyl cellulose, polyvinyl alcohol, PEG-containing block copolymer, and PEG are particularly preferred.

[0117] CLPAH-100 is a copolymer of PEG and acrylic acid, having vinyl groups at both ends, and its molecular structure is as follows. [ka] In the formula, R6 represents the polyethylene glycol chain.

[0118] As a solvent for hydrophilic polymer solutions, organic solvents containing CH bonds include Si-C n H 2n • Because radical transitions can occur from radicals, these cannot be used, and it is preferable to use water as a solvent. Also, although Si-radicals are relatively stable in water, they slowly form Si-OH groups at high temperatures. On the other hand, a certain amount of time and temperature is required for sufficient reaction between the hydrophilic polymer and the substrate. For this reason, immersion in the hydrophilic polymer solution is preferably carried out at a temperature of 5 to 50°C for about 20 minutes to 3 hours, and more preferably at a temperature of 10 to 30°C for about 30 minutes to 1 hour. When the temperature is set lower, it is preferable to lengthen the immersion time, and when the temperature is set higher, it is preferable to shorten the immersion time.

[0119] The concentration of the hydrophilic polymer in the solution varies depending on the type of hydrophilic polymer, but is usually between 0.01% and 1% by mass, and in many cases, 0.1% to 0.3% by mass is preferred. If there are insoluble substances in the polymer solution, it is preferable to filter it using filter paper that can separate retained particles of a few microns in size.

[0120] The thickness of the hydrophilic polymer layer can be controlled within a range of approximately 1 nm to several μm, depending on the type of hydrophilic polymer. For example, a hydrophilic polymer layer with a thickness of 5 nm or less (usually 1 nm to 5 nm) can be obtained by selecting a hydrophilic polymer without a crosslinking structure. A hydrophilic polymer layer with a thickness of 6 nm to 5 μm can be obtained by selecting a hydrophilic polymer with a crosslinking structure (e.g., CLPAH-100, a crosslinked polyacrylic acid and starch, a crosslinked polyacrylic acid and polyamide epichlorohydrin, etc.). In this case, the thickness of the hydrophilic polymer layer can also be controlled by adjusting the crosslinking density. Furthermore, in the case of a hydrophilic polymer with a crosslinking structure, it is also possible to control the thickness of the hydrophilic polymer layer by reducing the crosslinking structure by applying ultrasonic irradiation and using an aqueous solution filtered through a filter with an appropriate pore size.

[0121] After plasma treatment, the atmosphere before immersion in the hydrophilic polymer solution may be an inert gas atmosphere, but an oxygen-containing atmosphere is preferred. When immersed in an atmosphere containing a certain level of oxygen, Si-C n H 2n -Effective hydrophilization can be achieved by utilizing OO radicals (e.g., Si-CH2-OO radicals). In this case, the oxygen concentration of the atmosphere is preferably 0.5 to 20% by mass, more preferably 0.7 to 15% by mass, and particularly preferably 0.8 to 10% by mass.

[0122] Depending on the immersion conditions, additional heat treatment may be performed. If unreacted radicals remain, involving them in the reaction can increase the density of the bond between the hydrophilic polymer and the substrate. This additional heat treatment may be performed at a relatively high temperature; for example, it may be performed at 80°C to 135°C for 20 minutes to 2 hours, and preferably at 80°C to 135°C for 30 minutes to 1 hour.

[0123] After the hydrophilization treatment described above, the resulting lens may be optionally heated for sterilization. In this invention, since the substrate and the hydrophilic polymer form a stable covalent bond, sterilization can be performed in an autoclave. Heat sterilization can be performed, for example, by placing the lens in water and buffer solution (especially lens storage solution) and heating it under pressure at 121°C for 30 minutes. Depending on the immersion conditions, this sterilization treatment can also produce the same effect as the additional heat treatment described above, and is therefore beneficial in this respect as well.

[0124] 4. Soft eye lenses After the above hydrophilization treatment or heat treatment, the soft eye lens of the present invention can be obtained. The lens obtained by the plasma treatment and hydrophilization treatment described above comprises an ophthalmic lens substrate containing a (co)polymer having an alkyl group-containing polysiloxane structure, and a single coating layer containing a hydrophilic polymer on the surface of the substrate, and exhibits high hydrophilicity despite being a single coating layer.

[0125] The substrate is as described above, and in one embodiment, it consists of a (co)polymer obtained by polymerizing a (macro)monomer composition containing a polymerizable siloxane in a proportion of 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more. Substrates containing a large amount of polysiloxane structure have high oxygen permeability, and in a preferred embodiment, the lens of the present invention has an oxygen permeability (Dk value) of 150 or more. On the other hand, alkyl group-containing siloxanes, as described above, are localized on the substrate surface due to their water-repellent and hydrophobic properties, and even with a relatively small content, many radicals can be formed on the substrate surface by plasma treatment. As described above, hydrophilic polymers also bond to the alkyl-containing polysiloxane structure of the substrate through radical recombination and play a role in retaining moisture on the lens surface.

[0126] The hydrophilicity provided by a single coating layer can be confirmed by various parameters, and if surface-adsorbed water can be confirmed by XPS analysis under a water vapor pressure of 5 mbar, it can be evaluated that a higher level of hydrophilicity has been achieved. Furthermore, in a lens according to one embodiment of the present invention, the water contact angle of the coating layer surface is 70° or less, the water contact angle of the lens according to a preferred embodiment is less than 60°, the water contact angle of the lens according to a more preferred embodiment is less than 50°, and the water contact angle of the lens according to an even more preferred embodiment is less than 40°. Here, in this specification, "water contact angle" means the angle calculated by the tangential method between the water droplet and the lens surface when water is dropped onto the lens surface. Specifically, 1.5 μL of deionized water is dropped onto the lens surface provided with the coating layer, and the shape of the droplet is photographed from the side of the static water droplet immediately after dropping, and the contact angle is determined by the tangential method from the photographed shape of the droplet.

[0127] Furthermore, the lens of the present invention has the characteristic of having excellent abrasion resistance in the coating layer because the substrate and hydrophilic polymer are linked by numerous covalent bonds. Specifically, in the lens according to one embodiment of the present invention, the water contact angle after 20 abrasion tests is less than 80°, in the lens according to a more preferred embodiment, the water contact angle after 20 abrasion tests is 70° or less, in the lens according to an even more preferred embodiment, the water contact angle after 20 abrasion tests is 60° or less, in the lens according to an even more preferred embodiment, the water contact angle after 20 abrasion tests is 50° or less, and in the lens according to a particularly preferred embodiment, the water contact angle after 200 abrasion tests is 50° or less. In this specification, "rubbing test" refers to a test in which a sample is wet with pure water, rubbed a certain number of times (for example, 20 times, 200 times) while wearing nitrile rubber gloves, washed with pure water, the water adhering to the surface is wiped off, and purified water is dropped onto the sample, and the water contact angle is measured using the tangential method described above.

[0128] In the lens of the present invention, the substrate surface can be sufficiently hydrophilized with a single coating layer, so the thickness of the coating layer can be 1 nm to 5 nm. However, the thickness can also be increased by adsorbing a cross-linked polymer, in which case the thickness of the coating layer can be in the range of 6 nm to 5 μm.

[0129] Here, a conceptual diagram of the lens structure of the present invention is shown in Figure 1. The lens substrate contains a (co)polymer having an alkyl group-containing polysiloxane structure, and this (co)polymer is obtained by polymerizing a polysiloxane compound having a polymerizable functional group and an alkyl group, or by polymerizing these with other polymerizable compounds. When such a lens substrate is plasma treated, Si radicals and Si-C are formed on the substrate surface. n H 2n • SiC n H 2n -OO radicals are generated, Si-C n H 2n Radicals and, in some cases, Si-C n H 2n -OO· radicals are transferred to the hydrophilic polymer, and the portion having an alkyl group-containing polysiloxane structure is bonded to the hydrophilic polymer via the bonds shown in formula (4) and optionally formulas (5) and (6). [ka] (In the formula, R7 represents an alkyl group, R8 represents an alkylene, and X1 represents the carbon atom of a hydrophilic polymer.)

[0130] [ka] (In the formula, R9 represents an alkyl group, R 10 (where X1 represents alkylene, and X2 represents carbon in a hydrophilic polymer) [ka] (In the formula, R 11 (where X3 represents an alkyl group, and X3 represents a carbon atom of a hydrophilic polymer.)

[0131] The bonding pattern in formula (5) occurs when the substrate is plasma-treated and then exposed to an oxygen-containing atmosphere for a short time, or when hydrophilization treatment is performed in an oxygen-containing atmosphere, and a water-soluble polymer that is relatively prone to radical formation (for example, a hydrophilic polymer with atoms having non-covalent bonds or double bonds) is selected. In this case, the carbon atoms adjacent to the atoms having non-covalent bonds or double bonds in the hydrophilic polymer bond with the oxygen in the Si-alkylene-OO of the substrate.

[0132] The bonding pattern of formula (6) occurs when a water-soluble polymer that is more likely to form radicals is selected (a hydrophilic polymer having atoms with two non-covalent pairs or a double bond, or an atom with a non-covalent pair and a double bond, such as PVP), in which the carbon adjacent to the atom with the non-covalent pair or the double bond in the hydrophilic polymer is bonded to the Si of the substrate.

[0133] Furthermore, Si· radicals formed near the surface of the lens substrate eventually form Si-OH groups (silanol groups), and these silanol groups undergo dehydration condensation as shown below. [ka] As a result, the (co)polymer having a polysiloxane structure is crosslinked by siloxane bonds (Si-O-Si). If a hydrophilic polymer is present nearby during the condensation reaction, the hydrophilic polymer becomes entangled with the crosslinked polysiloxane (co)polymer, improving its resistance to abrasion. Furthermore, siloxane bonds are also formed inside the contact lens located below the bonding region, and it is thought that this condensation of silanol groups suppresses the diffusion of hydrophobic polymers to the surface.

[0134] To illustrate with an example using a substrate containing PDMS and PVP as a hydrophilic polymer, plasma treatment generates Si· radicals, Si-CH2· radicals, and, in the case of exposure to the oxygen-containing atmosphere described above, Si-CH2-OO· radicals on the substrate surface. These Si-CH2· radicals, and possibly Si-CH2-OO· radicals, are transferred to the PVP, generating the following radicals. The recombination of these radicals between the substrate and PVP forms covalent bonds of formulas (4) and (6), or (4) to (6). [ka]

[0135] Even when polyethylene glycol (PEG) is used as a hydrophilic polymer, radical transitions easily form radicals by abstracting a hydrogen atom from the methylene group adjacent to the oxygen atom, and mainly covalent bonds of formulas (4) and (6), or (4) to (6), are formed. In PEG, all methylene groups are equivalent, so the radicals that transition to the methylene groups can resonate with two oxygen atoms, and recombination with Si· radicals is easily facilitated.

[0136] In this way, the lens of the present invention has a hydrophilic polymer supported on a substrate by numerous covalent bonds, and water is retained on the lens surface by the hydrophilic polymer. In the lens according to a preferred embodiment of the present invention, 5% or more of the alkyl group-containing siloxane units present on the substrate surface are bonded to the carbon atoms of the hydrophilic polymer, and in the lens according to a more preferred embodiment, 10% or more of the alkyl group-containing siloxane units present on the substrate surface may be bonded to the carbon atoms of the hydrophilic polymer.

[0137] As described above, according to the present invention, it is possible to reliably, strongly, and efficiently coat a substrate with a hydrophilic polymer through a radical recombination mechanism. As a result, even when oxygen permeability is increased by increasing the silicone content and the feeling of dryness during wear is reduced, the lens surface is sufficiently hydrophilic, allowing for comfortable long-term wear. Furthermore, because the hydrophilic polymer is covalently bonded to the substrate through numerous radical recombinations, the coating layer has excellent scratch resistance, enabling repeated use of the lens. Moreover, since hydrophilization can be achieved with a single hydrophilic polymer layer, the manufacturing process is simplified, and productivity can be improved. [Examples]

[0138] The present invention will be further described below with reference to the following examples, but the present invention is not limited thereto. In the examples, "%" indicates mass%.

[0139] 1. Evaluation of surface chemical changes and hydrophilization when a substrate consisting solely of PDMS rubber is subjected to plasma treatment and coating with different compounds. This study aims to clarify how the surface of hydrocarbon group-containing polysiloxanes undergoes chemical changes due to inert gas plasma and what properties these changes result in. Furthermore, the surface properties of materials coated with three compounds—PVP, PEG, and decane—after plasma treatment will be compared.

[0140] 1-1. Preparation of the base material [Synthesis Example 1] In this test, a film-like PDMS rubber was used as the substrate. The PDMS rubber was prepared by crosslinking PDMS having vinyl groups at both ends (product name: SYLGARD 184, Silicone Elastomer, manufactured by DOW, weight-average molecular weight: 48000) with PDMS having hydrosilyl groups in its molecule (crosslinking solution of the above SYLGARD 184, weight-average molecular weight: 3500) in the presence of a platinum catalyst. The PDMS having vinyl groups at both ends and the crosslinking agent were mixed in a mass ratio of 20:1, processed into a 0.15 mm thick film after vacuum degassing, and heated at 90°C for 1 hour to allow the crosslinking reaction to proceed. This produced PMDS rubber with strength similar to that of soft contact lenses. This PMDS rubber was cut to an appropriate size and subjected to the plasma treatment and coating described below.

[0141] 1-2. Plasma treatment and coating [Example 1] After subjecting the PDMS rubber sample to plasma treatment, the sample surface was coated by immersion in a PVP aqueous solution. The plasma treatment was performed using a plasma generator (manufactured by Kai Semiconductor Co., Ltd., product name: YHS-DC100) in which two 10 cm diameter circular plate electrodes were installed parallel to each other at a distance of 5 cm inside the chamber. The sample was placed between the electrodes, the chamber was evacuated, and then nitrogen gas was introduced and the sample was irradiated with plasma for 30 seconds under a pressure of 20 Pa. The nitrogen gas flow rate was 10 sccm and the output power was 50 W. After plasma irradiation, nitrogen gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated PDMS rubber was immersed in a PVP aqueous solution (0.2 mass%, weight-average molecular weight 40,000) under a nitrogen atmosphere and left for 30 minutes.

[0142] [Example 2] PDMS rubber, which had been plasma-treated in the same manner as in Example 1, was immersed in an aqueous PEG solution (0.2% by mass, weight-average molecular weight 1,000) under a nitrogen atmosphere and left for 30 minutes.

[0143] [Reference example 1] The PDMS rubber, which had been plasma-treated in the same manner as in Example 1, was placed in decane under a nitrogen atmosphere and immersed for 30 minutes. Unbonded decane was then removed with ethanol and dried.

[0144] 1-3. Characteristic Evaluation 1-3-1. Evaluation of hydrophilicity based on water contact angle (1) Test method The water contact angle of the samples obtained in Examples 1 and 2 and Reference Example 1 was measured using 1.5 μL of deionized water. As a control, the contact angle of the substrate before plasma treatment was also measured. The water contact angle was determined by dropping 1.5 μL of deionized water onto a lens surface coated with a coating layer, immediately after dropping, photographing the shape of the droplet from the side in a static state, and then determining the contact angle from the photographed droplet shape using the tangential method.

[0145] (2) Test results The measurement results for the water contact angle of each sample are summarized below. [Table 1]

[0146] These test results suggest that when PDMS rubber is treated with an inert gas plasma, the PDMS rubber surface is highly activated, and PVP, PEG, and decane are bonded to it. The common structure of these adsorbed substances is a CH bond, and it is presumed that radicals capable of activating CH bonds originate from the -Si(CH3)2-O- group. The most likely radical is the Si-CH2· radical (Non-Patent Literature 4), which undergoes a radical transition with the CH group of the adsorbed substance, generating a radical on the carbon atom of the adsorbed substance, which is then expected to recombine with the Si-CH2· radical and silicon radical (Si·) on the PDMS rubber surface.

[0147] 1-3-2. Evaluation of hydrophilization level and bonding mode by XPS measurement The samples obtained in Example 1, Example 2, and Reference Example 1, as well as the PDMS rubber before and after plasma treatment, were analyzed for the adsorption of water molecules on the sample surface and the bonding mode between the substrate and the coating layer using a near-atmospheric pressure X-ray photoelectron spectroscopy (XPS) system (Tokyo Instruments Co., Ltd., EnviroESCA, monochromatic Al Kα X-rays (1486.6 eV, 42 W), pass energy (30 eV)). XPS measurements were performed within two days of sample preparation.

[0148] The vapor pressure of water is 25 mbar at room temperature, but first, the surface of each sample was measured using XPS at a water vapor pressure of 20 mbar. Adsorption of water was confirmed in all of the following samples: (1) substrate (PDMS rubber before plasma treatment), (2) PDMS rubber after plasma treatment using the method described in Example 1, (3) sample from Example 1 (PDMS rubber with adsorbed PVP after plasma treatment), (4) sample from Example 2 (PDMS rubber with adsorbed PEG after plasma treatment), and (5) sample from Reference Example 1 (PDMS rubber with adsorbed decane after plasma treatment).

[0149] Next, XPS measurements were performed on the surface of each sample under water vapor pressures of 20 mbar, 15 mbar, 10 mbar, 8 mbar, and 5 mbar. As models for the hydrophobic surface, the sample from Reference Example 1 (PDMS rubber with decane adsorbed after plasma treatment) and the sample from Example 2 (PDMS rubber with PEG adsorbed after plasma treatment) were used. As a result, it was found that both the decane-modified PDMS rubber and the PEG-modified PDMS rubber showed water adsorption up to 8 mbar, but no adsorption occurred at 5 mbar. This indicates that the water adsorption up to 8 mbar was monomolecular adsorption (langmear adsorption), and that both the surface of the decane-modified PDMS rubber and the surface of the PEG-modified PDMS rubber have the same level of Lennard-Jones potential. On the other hand, the water peak on the surface of the PEG-modified PDMS rubber shifted from 534.6 eV (20 mbar) to 534.2 eV (8 mbar), and the peak area also decreased to about one-third. The 0.4 eV shift mentioned above is thought to be due to a change in the sample's charge-up state caused by a decrease in adsorbed water. On the other hand, in the sample of Example 1, it was confirmed that water molecule adsorption occurred even at 5 mbar (Figure 2, Table 2). Furthermore, the water molecule peak was very sharp, and the full width at half maximum was 0.63 eV. This indicates that the water molecules were adsorbed in a state close to a gas, rather than as a condensed liquid. The PVP surface has a very high adsorption force to water molecules. Furthermore, the above XPS results do not indicate that PEG modification is unsuitable for hydrophilizing PDMS. The PEG-modified PDMS rubber shows a contact angle of 55.8° immediately after preparation, but increases to 74.7° after 90 minutes of exposure to air, and further rises to 90.4° after 22 hours. This indicates that the PEG on the surface is easily embedded in the PDMS rubber, while the PDMS is more easily exposed to the surface. Although the XPS measurements were performed between 24 and 48 hours after sample preparation, it is highly likely that the PEG surface became hydrophobic during that time. In other words, both PEG modification and PVP modification exhibit sufficient hydrophilicity immediately after preparation, but when left in air, the former tends to become hydrophobic, while the latter does not. However, even in the case of the former (Example 2), hydrophilicity can be maintained for a long period if stored in water.

[0150] In XPS measurements under a water vapor pressure of 5 mbar, the presence of carbonyl carbons in the O=CN bonds of the PVP side chains was confirmed at 287.76 eV in the C1s region of the sample from Example 1 (PDMS rubber with PVP adsorbed after plasma treatment). This is shown in Figure 3. Assuming that all carbonyl carbons originate from PVP, and judging from the detected amount of carbonyl carbons (10.1%), it is estimated that a PVP layer with a thickness of approximately 2.0 nm has been formed. However, in reality, not all radicals that transferred to PVP may have recombined with PDMS, and some may have been oxidized. Also, radicals on the methyl groups of PDMS may have been oxidized. Therefore, the actual thickness of the PVP layer is thought to be approximately 1 nm. On the other hand, in the sample of Example 2 (PDMS rubber with PEG adsorbed after plasma treatment), the presence of ether carbon in the -(CH2-CH2-O)- unit of the main chain was confirmed at 286.22 eV. This is shown in Figure 4. Judging from the amount of ether carbon detected (35.5%), it is thought that a PEG layer with a thickness of about 1.5 nm has been formed. In the case of PEG, all carbon atoms are bonded to oxygen, so in the C1s region, the proportion of carbon bonded to oxygen is very high.

[0151] Table 2 shows the C of each sample. 1s Region and O 1s The results of XPS measurements in the region were summarized. [Table 2] In the substrate (PDMS rubber before plasma treatment), only methyl carbon bonded to silicon is observed at 284.38 eV, but after plasma treatment, carbon atoms bonded to oxygen and carbon atoms in O=CO(N) can be confirmed. Comparing the data before and after plasma treatment, it can be seen that 11.5% of the methyl carbon is radicalized by the plasma. Interestingly, comparing the data before and after immersion in decane, the percentage of oxygen-bonded carbon atoms and more oxidized carbon atoms decreases to 7.8%. This indicates that radical transition reduces the radicals of the methyl groups in PDMS, preventing oxidation. What is noteworthy in Table 2 is that in the plasma-treated PDMS rubber, 8.3% of the carbon atoms were bonded to one oxygen atom, 3.2% were bonded to two oxygen atoms, and the remaining 88.5% of the carbon atoms were not oxidized. In other words, since the plasma treatment was performed under similar conditions in Examples 1 and 2, it is thought that in these samples as well, 11.5% of the methyl groups formed Si-CH2· radicals, and the remaining methyl groups (88.5%) did not generate Si-CH2· radicals immediately after plasma treatment. In other words, the plasma treatment conditions of the present invention are very mild.

[0152] Table 3 shows the N values ​​for each sample. 1s Region and Si 2pThe results of the XPS measurements in the region are summarized. Figures 5, 6, 7, and 8 show the Si obtained from XPS analysis of the sample from Synthesis Example 1 (PDMS rubber), the sample obtained by plasma treatment of the substrate from Synthesis Example 1, the sample from Example 1, and the sample from Reference Example 1, respectively. 2p The spectrum of the region is shown. [Table 3] In this XPS measurement, the oxidation state of Si changes, so the charge-up of Si and O in the PDMS main chain differs slightly from that of N and C. Therefore, in Tables 2 and 3, the charge-up values ​​of C and N are determined based on the C of the methyl group in PDMS, and the charge-up values ​​of O and Si are determined based on the O in the PDMS main chain. In the latter case, the accuracy of the charge-up correction is slightly reduced because the sample with adsorbed PEG contains 39% oxygen that does not originate from the PDMS main chain (see Table 2).

[0153] N 1s In this region, the presence of nitrogen at 399.71 eV was confirmed only in the sample of Example 1 (PDMS rubber with PVP adsorbed after plasma treatment). The peak area of ​​nitrogen was 450.5, and the peak area of ​​Si originating from PDMS was 2225. Considering the photoionization cross-sectional area ratio of nitrogen to silicon (1.8:0.817), the ratio of detected Si to N is 1:0.092. As a result, the thickness of the PVP is estimated to be about 1 nm.

[0154] Si in PDMS rubber before plasma treatment 2pIn the region measurements, peak fitting showed that a peak of Si bonded to the two methyl groups and two oxygen atoms of PDMS appeared at 101.63 eV with a full width at half maximum of 1.82 eV, accounting for 74.9% of the total, while the remaining 25.1% can be attributed to more oxidized Si (Figure 5). The latter is thought to be Si bonded to three oxygen atoms, suggesting that a portion of the PDMS chain has a branched structure via oxygen. On the other hand, in the PDMS rubber after plasma treatment, the peak of more oxidized Si (considered to be Si bonded to three oxygen atoms) increased by 14.8%. This result is because more than 14% of the Si-CH3 bonds in PDMS were cleaved and changed into Si-OH bonds, etc. (Figure 6). In contrast, as shown in Figure 7, in the sample of Example 1 (PDMS rubber with PVP adsorbed after plasma treatment), the Si bonded to three oxygen atoms increased by only 6.5% compared to the substrate. This difference (8.3%) suggests that in the sample of Example 1, oxidation was suppressed because PVP recombined with silicon radicals (Si·). On the other hand, in the sample of Reference Example 1 (PDMS rubber with decane adsorbed after plasma treatment), Si oxidation progressed more rapidly, and it is understood that it did not recombine with silicon radicals (Si·) (Figure 8). The sample of Example 2 (PDMS rubber with PEG adsorbed after plasma treatment) was analyzed using a similar method, but since the accuracy of the charge-up correction was low only for this sample, we will refrain from discussing it further. On the other hand, Table 3 shows Si 2p The full width at half maximum (FMAX) of the entire peak is shown. In the PDMS rubber before plasma treatment, this value is 2.22 eV (Figure 5), but it increases to 2.41 eV after plasma treatment. That is, the peak becomes wider as oxidation of Si progresses. However, in the sample with adsorbed PVP, the peak becomes sharper at 2.04 eV (Figure 7). On the other hand, when decane is adsorbed, it becomes 2.47 eV, which is almost the same as the value after plasma treatment. This supports the idea that decane is not bound to silicon radicals (Si·). The full width at half maximum when PEG is adsorbed is almost the same as when PVP is adsorbed, and from this result, it is thought that PEG is bound to silicon radicals (Si·). Thus, the adsorption of hydrophilic polymers by the method of the present invention is characterized by a small full width at half maximum (FWHM) of Si in XPS measurements. Another notable feature in Table 3 is that Si bonded to two oxygen atoms was observed in all samples at 101.63 eV. When the plasma irradiation conditions are intense and many of the Si-C bonds of the -Si(CH3)2-O- group in PDMS are dissociated, the Si atoms in PDMS become more oxidized and bond to three or four oxygen atoms. However, in Table 3, more than 60% of the Si atoms in PDMS are bonded to methyl groups after plasma treatment. Subsequently, in the sample of Example 1, where PVP was adsorbed, more than 68% of the Si atoms were bonded to two oxygen atoms (Figure 7), and even when decane was adsorbed, more than 50% of the Si atoms were bonded to two oxygen atoms (Figure 8).

[0155] 2. Evaluation of surface hydrophilicity when a substrate obtained by polymerizing a composition containing other (macro) monomers together with polymerizable PDMS is subjected to plasma treatment and hydrophilization with a hydrophilic polymer. In this study, the surface properties of samples obtained by polymerizing a substrate containing a composition with polymerizable PDMS along with other macromonomers and monomers were evaluated after being subjected to plasma treatment with an inert gas and hydrophilization treatment.

[0156] 2-1. Preparation of the base material [Synthesis Example 2] A mixture of 28 parts by mass of polydimethylsiloxane having methacryloyl groups at both ends, 7 parts by mass of polydimethylsiloxane having a methacryloyl group at one end, 57.9 parts by mass of trifluoromethyl acrylate, 7 parts by mass of 2-ethylhexyl acrylate, 0.1 parts by mass of dimethylaminoethyl acrylate, 0.5 parts by mass of UV absorber (RUVA-93), 0.01 parts by mass of colorant (RB246), 0.5 parts by mass of polymerization initiator (Irgacure 819), and 10 parts by mass of t-amyl alcohol was prepared. The mixed solution was filtered and injected between two polypropylene molds, and polymerization was carried out by UV irradiation. After polymerization, the molds were separated, unreacted monomers were removed by immersion in isopropyl alcohol at 60°C for 2 hours, washed again with isopropyl alcohol, and air-dried at room temperature to obtain the substrate.

[0157] 2-2. Preparation of lens samples [Example 3] After subjecting the substrate to plasma treatment, the substrate surface was coated by immersion in a PVP aqueous solution. The plasma treatment was performed using a plasma generator in which two 20 cm diameter circular plate electrodes were placed parallel to each other with a 5 cm gap inside the chamber. The substrate was placed between the electrodes, the chamber was purged with vacuum, and then nitrogen gas was introduced and the sample was irradiated with plasma for 30 seconds under a pressure of 19 Pa. The nitrogen gas flow rate was 10 sccm and the output was 50 W. After plasma irradiation, nitrogen gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a PVP aqueous solution (0.2 mass%, weight-average molecular weight 1,300,000) under a nitrogen atmosphere and left for 30 minutes. Subsequently, the PVP aqueous solution containing the substrate was transferred to a vial in the air, heat-treated at 121°C for 1 hour (sterilization), and then further sterilized at 121°C for 30 minutes in contact lens storage solution (Seed Co., Ltd., Softcare Pure). After rinsing thoroughly with water to remove any water adhering to the surface, the sample was subjected to testing.

[0158] 2-3. Characteristic Evaluation 2-3-1. Evaluation of hydrophilicity based on water contact angle The contact angle of the sample obtained in Example 3 was measured according to the procedure described in 1-3-1. The sample obtained in Example 3 exhibited superhydrophilicity, making it impossible to measure the contact angle.

[0159] 2-3-2. Scratch Test The sample obtained in Example 3 was wet with pure water, rubbed 20 times with nitrile rubber gloves, washed with pure water, and the water adhering to the surface was wiped off. The contact angle was then measured according to the procedure described in 1-3-1. The contact angle of the sample obtained in Example 3 after the rubbing test was 50.1°.

[0160] 2-3-3. Evaluation of surface properties by XPS analysis For the samples obtained in Example 3 and the substrates before and after plasma treatment, a quasi-atmospheric pressure X-ray photoelectron spectroscopy (XPS) apparatus (manufactured by Tokyo Instruments, EnviroESCA, monochromatic Al Kα X-ray (1486.6 eV, 42 W), pass energy (30 eV)) was used to analyze the adsorption of water molecules on the surface and the bonding mode between the substrate and the coating layer. For the substrate after plasma treatment, the measurement was carried out one week after the plasma treatment.

[0161] In the sample obtained in Example 3, in the XPS measurement under a water vapor pressure of 5 mbar, a prominent water peak was confirmed in the region of O 1s . The results are shown in Fig. 9. The water peak is considered to include both the gaseous state and the liquid state. Also, between the oxygen of the Si-O-Si bond and the oxygen of water, there is the oxygen of Si-OH, but due to the broadness of the water peak, it is not split as a peak. On the other hand, in the substrates before and after plasma treatment, no water peak was confirmed, and it was confirmed that the surface was hydrophobized. The substrate subjected to plasma treatment showed high hydrophilicity (water contact angle of 19.4°) immediately after plasma irradiation, but became hydrophobic (water contact angle of 80° or more) the next day, so it is considered that less water was adsorbed. This is because hydrophobic PDMS diffuses from the inside to the surface.

[0162] In the XPS measurement under a water vapor pressure of 5 mbar, when comparing the full width at half maximum (FWHM value) of the entire Si peak before curve fitting in the Si 2p region, the substrate before plasma treatment was 1.79 eV, while the substrate after plasma treatment widened to 2.13 eV. This indicates that the Si of PDMS is oxidized, as shown in the same test conducted on a substrate made of PDMS rubber. On the other hand, in the sample obtained in Example 3, the full width at half maximum shrank to 1.63 eV. This is also considered to be because the oxidation of silicon radicals (Si·) was suppressed by the bonding of PVP, as shown in the same test conducted on a substrate made of PDMS rubber.

[0163] XPS measurements under a water vapor pressure of 5 mbar revealed peaks in the C1s region originating from CF3 groups and O=CO bonds in the substrate before and after plasma treatment. Figure 10 shows the XPS spectrum of the substrate after plasma treatment (without PVP adsorption). The substrate was manufactured by polymerizing a mixture containing 57.9 parts by mass of trifluoromethyl acrylate and 28 parts by mass of polydimethylsiloxane having methacryloyl groups at both ends, and these peaks are understood to originate from these components. Furthermore, after plasma treatment, in addition to COC bonds, there were also many photoelectrons from HOC bonds, which are understood to be caused by the oxidation of methyl group radicals of PDMS. On the other hand, the C of the sample obtained in Example 3 1s In the XPS spectrum of this region, as shown in Figure 11, the peaks originating from the CF3 group and O=CO are extremely weak, and the oxidation of the radical (Si-CH2·) on the methyl group of PDMS is suppressed, resulting in a smaller shoulder from the HOC bond. However, the presence of both ester and amide bonds broadens the peaks originating from O=CN and O=CO. Interestingly, the spectrum in Figure 11 is very similar to that of the sample in Figure 3 in which PVP was adsorbed onto PDMS rubber, except for the weak CF3 and broadened O=CO(N) peaks. This suggests that the binding of PVP to PDMS increases the concentration of PDMS near the surface, allowing the portion derived from trifluoromethyl acrylate to relatively penetrate. In other words, it is understood that the PDMS in the substrate becomes hydrophilic due to binding with PVP, similar to the substrate made of PDMS rubber. From the XPS spectra of the substrate after plasma treatment and the sample obtained in Example 3, the ratio of nitrogen to carbon present on the surface was calculated. The sample obtained in Example 3 contained 3.03 nitrogen atoms for every 100 carbon atoms. Since no X-ray photoelectrons were emitted around 400 eV from the substrate after plasma treatment, it is clear that PVP was bonded to the substrate in the sample obtained in Example 3. From the XPS spectra of both samples, the thickness of the PVP layer in the sample obtained in Example 3 is estimated to be approximately 1 nm.

[0164] 3. Analysis of the surface condition of the substrate after plasma treatment. In this study, the modified state of the substrate surface was analyzed after the prepared substrate was plasma-treated. [Reference example 2] 3-1. Test Method A substrate prepared according to [Synthesis Example 2] was plasma-treated using the procedure described in [Example 3], and the water contact angle of the substrate surface before and after plasma treatment was measured according to the procedure described in 1-3-1. 3-2. Test Results The water contact angle of the substrate surface before plasma irradiation was measured to be 111°. This value is close to the contact angle of PDMS rubber (117.4°, see Table 1) and is almost equal to the contact angle of untreated PDMS reported in papers and other publications. The substrate prepared in [Synthesis Example 2] has such a water contact angle despite being made by polymerizing a composition containing various macromonomers and monomers in addition to polydimethylsiloxane with methacryloyl groups. From this, it can be understood that the surface of the substrate is almost completely covered with PDMS. This is because the surface tension of PDMS is 20-22 mN / m, which is significantly lower than that of other hydrocarbon polymers, so the surface is more thermodynamically stable when covered with PDMS. When the substrate prepared in [Synthesis Example 2] was irradiated with plasma and the water contact angle of the substrate surface was measured immediately afterward, it decreased to an average of 40.7° (n=9). However, when the water contact angle was measured a few days later, it was around 90°, and after 14 days, the water contact angle increased to an average of 109.4° (n=9). In other words, it returned to almost the initial value in two weeks. These fluctuations in the water contact angle indicate that the surface of the substrate fabricated in [Synthesis Example 2] was covered with PDMS, which was activated (radical formation) by the plasma, then deactivated (radical stabilization) upon exposure to the atmosphere, causing the internal PDMS to migrate to the surface and return to its original surface state. The large water contact angle observed after plasma treatment in Reference Example 1 can also be explained by similar reasons.

[0165] 4. Influence of differences in oxygen content in the atmosphere on surface hydrophilization during hydrophilic treatment with hydrophilic polymer solutions In this study, we investigated whether varying the oxygen content in the atmosphere during hydrophilization treatment affects the hydrophilization process.

[0166] [Examples 4 to 6] 4-1. Preparation of lens samples Plasma treatment and hydrophilization treatment were performed in the same manner as in Example 3, except that after plasma treatment, the substrate was held in a nitrogen atmosphere with an oxygen concentration of 0.5% by mass, 1.0% by mass, or 18.4% by mass for 3 seconds, and then immersed in a PVP aqueous solution (0.2% by mass, weight-average molecular weight 40,000) under a nitrogen atmosphere.

[0167] 4-2. Abrasion Test Abrasion tests were performed on the samples obtained in Examples 4 to 6 according to the procedure described in 2-3-2. The contact angles after abrasion were 45.1° for the sample in Example 4, which was exposed to an atmosphere with an oxygen concentration of 0.5 mass% for a short time after plasma treatment; 32.3° for the sample in Example 5, which was exposed to an atmosphere with an oxygen concentration of 1.0 mass%; and 34.4° for the sample in Example 6, which was exposed to an atmosphere with an oxygen concentration of 18.4 mass%. It was demonstrated that exposing the sample to an oxygen-containing atmosphere for a short time after plasma treatment can strongly bond more hydrophilic polymers to the substrate. In particular, exposure to an atmosphere with an oxygen concentration of about 1.0% resulted in the strongest bonding of the most hydrophilic polymers. This also indicates that the use of Si-COO· radicals is effective in more efficiently bonding hydrophilic polymers to the substrate.

[0168] 5. Influence of differences in molecular weight of hydrophilic polymers on hydrophilization In this study, we investigated whether differences in the molecular weight of the hydrophilic polymers affect hydrophilization by hydrophilizing substrates containing alkyl groups siloxanes using the same type of hydrophilic polymer with different molecular weights.

[0169] [Examples 7 and 8] 5-1. Preparation of lens samples Lens samples were prepared under the same conditions and procedures as in Example 3, except that the plasma-treated substrate was immersed in an aqueous solution (0.2 mass%) of PVP with a weight-average molecular weight of 350,000 or 40,000.

[0170] 5-2. Evaluation by abrasion test Abrasion tests were performed on the samples obtained in Examples 7 and 8 according to the procedure described in 2-3-2. The contact angle after abrasion treatment was 51.5° for the sample in Example 7 (weight-average molecular weight of 350,000) and 49.8° for the sample in Example 8 (weight-average molecular weight of 40,000). For the sample in Example 3 (weight-average molecular weight of 1,300,000), the contact angle was 50.1°. No difference in the contact angle after abrasion treatment was observed due to the difference in the molecular weight of the PVP.

[0171] 6. Surface hydrophilization using different hydrophilic polymers In this study, the surface of a substrate was made hydrophilic using different hydrophilic polymers, and the hydrophilicity was evaluated.

[0172] 6-1. Preparation of lens samples [Example 9] After subjecting the substrate to plasma treatment, the substrate surface was coated by immersion in an aqueous polyacrylic acid solution. After plasma treatment was performed according to the conditions and procedures described in [Example 3], the sample was held in a nitrogen atmosphere with an oxygen concentration of 18.06% by mass for 3 seconds, then immersed in an aqueous polyacrylic acid solution (0.2% by mass, weight-average molecular weight 240,000) under a nitrogen atmosphere and left for 30 minutes. Subsequently, the aqueous polyacrylic acid solution containing the substrate was transferred to a vial in air and heat-treated (sterilized) at 121°C for 30 minutes. The treated substrate was then placed in deionized water and heat-treated again at 121°C for 30 minutes. After heat treatment, the sample was thoroughly rinsed with water, any water adhering to the surface was wiped off, and it was thoroughly dried. Furthermore, comparative experiments have confirmed that sterilization with deionized water has a similar effect to sterilization with contact lens storage solution, and there is no significant difference in the contact angle values ​​after the rubbing test. However, sterilization with deionized water may cause irritation to the eyes upon application, so sterilization with contact lens storage solution is preferable when evaluating wearing performance.

[0173] [Example 10] After subjecting the substrate to plasma treatment, it was immersed in an aqueous chondroitin sulfate solution to coat the substrate surface. After performing plasma treatment, nitrogen gas was introduced, the chamber was returned to normal pressure, and the substrate treated with plasma under a nitrogen atmosphere was immersed in an aqueous chondroitin sulfate solution (0.1% by mass), and plasma treatment and hydrophilic treatment were performed in the same manner as in [Example 3], except that it was left standing for 30 minutes. In this example, since chondroitin sulfate is easily soluble in water and in order to evaluate the durability of the bond with the contact lens, it was sterilized with deionized water for 1 hour. In the guidelines for sterilization methods of medical devices (ISO / TS 17665-2), the sterilization temperature of autoclave treatment is defined as a holding time of 121°C for 15 minutes or more, but in the present invention, a longer treatment time is set in order to confirm surface deterioration due to heat treatment.

[0174] [Example 11] After subjecting the substrate to plasma treatment, it was immersed in an aqueous hydroxyethyl cellulose solution to coat the substrate surface. After performing plasma treatment, nitrogen gas was introduced, the chamber was returned to normal pressure, and the substrate treated with plasma under a nitrogen atmosphere was immersed in an aqueous hydroxyethyl cellulose solution (0.1% by mass), and plasma treatment and hydrophilic treatment were performed in the same manner as in [Example 3], except that it was left standing for 30 minutes.

[0175] [Example 12] After subjecting the substrate to plasma treatment, it was immersed in an aqueous solution of an ethylene glycol-crosslinked polymer of polyacrylic acid to coat the substrate surface. After performing plasma treatment, nitrogen gas was introduced, the chamber was returned to normal pressure, and the substrate treated with plasma under a nitrogen atmosphere was immersed in an aqueous solution (0.2% by mass) of an ethylene glycol-crosslinked polymer of polyacrylic acid (trade name: CLPAH-100, manufactured by Fujifilm Corporation), and plasma treatment and hydrophilic treatment were performed in the same manner as in [Example 3], except that it was left standing for 30 minutes.

[0176] 6-2. Characterization (Water Contact Angle and Abrasion Test) Following the procedures described in 1-3-1 and 2-3-2, water contact angle measurements and abrasion tests were performed on the samples obtained in Examples 9 to 12. The water contact angles of each sample before and after abrasion, along with those of the sample from Example 3, are summarized below. [Table 4] As shown in Table 4, contact lenses modified with PVP and CLPAH-100 exhibit a superhydrophilic surface and a small water contact angle after abrasion testing. Polyacrylic acid, hydroxyethylcellulose, and chondroitin sulfate also showed small contact angles after abrasion testing, suggesting that similar performance to PVP and CLPAH-100 can be achieved by optimizing the experimental conditions. In a comparison of the transparency of contact lenses after drying, those modified with PVP showed the best results. This is likely because PVP is an amorphous polymer and retains its transparency even after drying. On the other hand, polyacrylic acid tends to cause slight clouding of the surface when adsorbed onto contact lenses and dried. Therefore, it is necessary to adjust the adsorption conditions, such as pH. In the case of hydroxyethylcellulose, the dispersibility of the polymer may be poor, so it is better to select a grade with high dispersibility and low ash content. Although not shown in Table 4, hyaluronic acid and alginic acid can also be hydrophilized in the same way as chondroitin sulfate. However, these also tend to cause slight clouding when dried.

[0177] 6-3. Characterization (Evaluation of surface properties by XPS analysis and abrasion test) The sample obtained in Example 12 was wet with pure water, rubbed 20 times with nitrile rubber gloves, washed with pure water, and the water adhering to the surface was wiped off. The sample, as well as the substrate before and after plasma treatment, were subjected to X-ray photoelectron spectroscopy (XPS) under high vacuum using a Thermo Fisher Scientific K-Alpha X-ray photoelectron spectrometer (XPS). + The bonding mode between the substrate and the coating layer was analyzed using Al Kα single-crystal spectroscopy. The X-ray spot diameter was set to 400 μm, and measurements were taken one week after plasma treatment of the substrate. Before plasma treatment, the C:O:N:F:Si ratio in the substrate was 52.8:24.2:0.2:3.7:19.3, while after plasma treatment, it became 61.5:21.9:2.4:0.9:13.4. After plasma treatment, a small amount of nitrogen atoms were introduced into the substrate, with a relative abundance of 2.4%. On the other hand, plasma treatment reduced the amount of fluorine atoms and increased the amount of carbon atoms on the substrate surface. This is likely because part of the cross-linking structure of the substrate was decomposed by the plasma treatment, causing PDMS to become unevenly distributed on the surface, while trifluoromethyl acrylate was deposited. In the sample obtained in Example 12 (a substrate immersed in an aqueous solution of CLPAH-100), the ratio of C:O:N:F:Si was 58.8:27.1:0.3:0.5:13.3. The increased oxygen content is due to the high oxygen content of CLPAH-100. 1s In the region, the 286.4 eV component derived from CO bonds increased significantly from 6.7% in the substrate after plasma treatment to 20.8% in the sample obtained in Example 12. When the sample obtained in Example 12 was rubbed with rubber gloves, the 286.4 eV component decreased to 8.4%, but this is still considerably higher than that of the substrate after plasma treatment, indicating that a large amount of hydrophilic polymer remains. The surface of the contact lens before the abrasion test exhibits superhydrophilicity. That is, water droplets spread out immediately, making it impossible to measure the contact angle. Furthermore, the contact lens after the abrasion test showed a contact angle of 51.6° even after being left in the air for 7 days. This indicates that the surface is covered with a hydrophilic polymer.

[0178] 7. Influence of differences in (macro) monomer composition for substrate preparation on hydrophilization In this study, we investigated the effect of varying the (macro) monomer composition used to prepare the substrate on its hydrophilicity.

[0179] 7-1. Preparation of the base material [Synthesis Example 3] The substrate was obtained under the same conditions and procedures as in Synthesis Example 2, except that the content of trifluoromethyl acrylate was set to 38.6 parts by mass, and the amount of 2-ethylhexyl acrylate was increased by the same amount as the decrease in trifluoromethyl acrylate.

[0180] [Synthesis Example 4] The substrate was obtained under the same conditions and procedures as in Synthesis Example 2, except that the content of trifluoromethyl acrylate was set to 19.3 parts by mass, and the amount of 2-ethylhexyl acrylate was increased by the same amount as the decrease in trifluoromethyl acrylate. 7-2. Plasma treatment and coating [Examples 13 and 14] Except for using the substrates from Synthesis Examples 3 and 4, plasma treatment and hydrophilization treatment were performed under the conditions and procedures described in Example 12.

[0181] 7-3. Characterization (Contact Angle and Abrasion Test) Contact angle measurements and abrasion tests were performed on the substrates before plasma treatment and on the samples obtained in Examples 13 and 14, following the procedures described in 1-3-1 and 2-3-2. The results are summarized below. [Table 5] The water contact angle before rubbing was superhydrophilic in all samples of Examples 12 to 14, indicating that variations in monomer content other than alkyl group-containing siloxanes did not significantly affect the bonding of the hydrophilic polymer, suggesting that hydrocarbon group-containing polysiloxanes are involved in the bonding of the hydrophilic polymer to the substrate. On the other hand, the contact angle after rubbing tended to increase as the trifluoromethyl acrylate content decreased. This is thought to be because substrates with low monomer content are very soft, resulting in greater distortion when rubbed with rubber gloves, making it easier for CLPAH-100 to peel off (or for PDMS to come to the surface). The mechanical strength of a contact lens is, to some extent, influenced by the stability of its hydrophilic coating layer.

[0182] 8. Investigation of different plasma generation methods and hydrophilization using different hydrophilic polymers. In this test, plasma was generated by glow discharge, and the surface of the substrate was hydrophilized using different hydrophilic polymers, and the hydrophilicity was evaluated.

[0183] 8-1. Preparation of lens samples [Example 15] A plasma generator (manufactured by Maywa Focus Co., Ltd., trade name: SEDE (Soft Etching Device)) equipped with a glow discharge type parallel plate electrode with a diameter of 9 cm (electrode distance: 4 cm) was used. Nitrogen gas was introduced from a needle valve, and plasma was generated at a pressure of 20 Pa and a current of 15 mA, and the substrate prepared according to [Synthesis Example 2] was irradiated for 10 seconds. After plasma irradiation, nitrogen was introduced to return the chamber to normal pressure, and it was immersed in an aqueous solution (1.0% by mass) of polyvinyl alcohol with a molecular weight of 25,000 in a nitrogen atmosphere with an oxygen concentration of 0.2% and left for 1 hour. After rinsing with water, it was put into a contact lens preservation solution (manufactured by Seed Co., Ltd., Softcare Pure), and further heat-treated at 121°C for 30 minutes. After the heat treatment, the sample was thoroughly rinsed with water to remove the water adhering to the surface.

[0184] [Example 16] A lens sample with a hydrophilized surface was prepared in the same manner as in Example 15, except that the substrate after plasma treatment was immersed in an aqueous solution (1.0% by mass) of Pluronic F-127 (a block copolymer containing PEG, a surfactant) in a nitrogen atmosphere with an oxygen concentration of 0.6%.

[0185] [Example 17] A lens sample with a hydrophilized surface was prepared in the same manner as in Example 15, except that the substrate after plasma treatment was immersed in an aqueous solution (1.0% by mass) of PEG with a molecular weight of 一千 in a nitrogen atmosphere with an oxygen concentration of 0.6%. In Examples 15 to 17, since nitrogen substitution was performed using a simple type glove bag made of polyolefin, the oxygen concentration measured by an oxygen concentration meter fluctuates slightly due to the deterioration of the glove bag.

[0186] 8-2. Characterization (Water Contact Angle and Abrasion Test) Contact angle analysis and abrasion tests were performed on the samples obtained in Examples 15 to 17 according to the procedures described in 1-3-1 and 2-3-2. However, for the samples obtained in Examples 16 and 17, the abrasion test was performed 10 times. The test results are summarized below. [Table 6] As shown in Table 6, hydrophilic polymers can be adsorbed even when using plasma generated by glow discharge, and it can be seen that polyvinyl alcohol, Pluronic F-127, and PEG can be made hydrophilic. Furthermore, in at least 10 abrasion tests, the water contact angle did not decrease significantly and remained below 70°. However, compared to low-frequency plasma, plasma generated by glow discharge is unstable and has a higher intensity. For this reason, the plasma irradiation time is set to one-third (10 seconds) of that of the former, but control is difficult due to the short duration. In particular, with glow discharge, the plasma is unstable for the first 0.5 seconds. Also, because electrons flow in a specific direction, variations tend to occur between the front and back of the contact lens. Therefore, when using glow discharge for surface modification of contact lenses, it will be necessary to devise a method for transporting the contact lenses into the plasma.

[0187] 9. Examination of plasma generation conditions In this study, plasma was generated under different conditions, and its effect on hydrophilization was investigated.

[0188] [Example 18] 9-1. Preparation of lens samples Plasma treatment was performed using a plasma generator (manufactured by Kai Semiconductor Co., Ltd., product name: YHS-DC100) in which two 10 cm diameter circular plate electrodes were installed parallel to each other with a 5 cm gap inside the chamber. The substrate prepared according to [Synthesis Example 2] was placed between the electrodes, the chamber was purged with vacuum, and then nitrogen gas was introduced and the sample was irradiated with plasma for 30 seconds under a pressure of 20 Pa. The nitrogen gas flow rate was 10 sccm and the output was 50 W. After plasma irradiation, nitrogen gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a CLPAH-100 aqueous solution (0.3 mass%) under a nitrogen atmosphere and left for 30 minutes. After that, the CLPAH-100 aqueous solution containing the contact lens was transferred to a vial in air and heated at 121°C for 30 minutes. After thorough washing with water, it was placed in a contact lens storage solution (Seed Co., Ltd., Soft Care Pure) and further heated at 121°C for 30 minutes. After heat treatment, the sample was thoroughly rinsed with water to remove any water adhering to the surface.

[0189] 9-2. Characterization (Contact Angle and Abrasion Test) Contact angle measurements and abrasion tests were performed on the samples obtained according to the procedures described in 1-3-1 and 2-3-2. The sample obtained in Example 18 was superhydrophilic (water contact angle could not be measured), and the contact angle after abrasion treatment was 58.3°. Furthermore, it showed a water contact angle of 70.5° even 4 days after the abrasion test.

[0190] 10. Consideration of gas flow rate during plasma processing This study evaluated the effect of different nitrogen gas flow rates during plasma treatment on the activation of the substrate surface. [Reference Examples 3 and 4] 10-1. Plasma treatment The substrate prepared in [Synthesis Example 2] was subjected to plasma treatment only, following the procedure and conditions described in [Example 3], except that the nitrogen gas flow rate was increased to 20 sccm or 30 sccm. 10-2. Evaluation of activation of the substrate surface (water contact angle) The water contact angles of the substrates in Reference Examples 3 and 4 were measured according to the procedure described in 1-3-1. In Reference Example 2, the water contact angle of the substrate treated with plasma at a nitrogen gas flow rate of 10 sccm was 40.7°, whereas in Reference Examples 3 and 4, where the nitrogen gas flow rates were 20 sccm and 30 sccm, the water contact angles of the substrates were 46.6° and 63.1°, respectively. Therefore, it was suggested that increasing the nitrogen gas flow rate leads to increased activation of the substrate surface, i.e., a decrease in the number of radicals. This is thought to be because an increase in the inflowing nitrogen gas reduces the concentration of active species in the nitrogen plasma, and a larger gas inflow also lowers the gas temperature, resulting in a milder plasma. Since hydrophilicity can be improved by increasing the plasma irradiation time, it is desirable to set a longer irradiation time when increasing the gas inflow.

[0191] 11. Examination of the chamber atmosphere in plasma processing (1) In this experiment, plasma was generated under a CO2 gas atmosphere, and its effect on hydrophilization was investigated.

[0192] [Comparative Example 1] 11-1. Preparation of lens samples Lens samples were prepared in the same manner as in Example 18, except that the atmosphere inside the chamber was changed from nitrogen gas to CO2 gas. In Example 18, a substrate prepared according to Synthesis Example 2 was placed between the electrodes of the plasma generator. After purging the chamber with vacuum, CO2 gas was introduced and the sample was irradiated with plasma for 30 seconds under a pressure of 20 Pa. The CO2 gas flow rate was 10 sccm and the output was 50 W. After plasma irradiation, CO2 gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a CLPAH-100 aqueous solution (0.3 mass%) and left for 30 minutes. After washing with water, the CLPAH-100 aqueous solution containing the contact lens was transferred to a vial in air and heated at 121°C for 30 minutes. After thorough washing with water, the sample was placed in a contact lens storage solution (Seed Co., Ltd., Soft Care Pure) and further heated at 121°C for 30 minutes. After the heat treatment, the sample was thoroughly rinsed with water to remove any water adhering to the surface.

[0193] 11-2. Characterization (Water Contact Angle and Abrasion Test) Water contact angle measurements and abrasion tests were performed on multiple samples (n=6) according to the procedures described in 1-3-1 and 2-3-2. [Table 7] Table 7 shows the changes in water contact angle on the surfaces of the six samples in Comparative Example 1. When using N2 plasma, the contact angle after rinsing becomes superhydrophilic, but with CO2 gas plasma, there is a large variation. After the abrasion test, the variation is relatively small, and the bonding of CLPAH-100 can be confirmed. However, after 4 days of exposure to air, some samples showed a water contact angle of 91.6°, suggesting that CLPAH-100 is easily peeled off.

[0194] 12. Examination of the chamber atmosphere in plasma processing (2) In this experiment, plasma was generated in an air atmosphere, and its effect on hydrophilization was investigated.

[0195] [Comparative Example 2] 12-1. Preparation of lens samples Lens samples were prepared in the same manner as in Example 18, except that the atmosphere inside the chamber was changed from nitrogen gas to air (oxygen concentration: 21%). In Example 18, a substrate prepared according to Synthesis Example 2 was placed between the electrodes of the plasma generator used. After purging the chamber with vacuum, air (oxygen concentration: 21%) was introduced from the outside and the sample was irradiated with plasma for 30 seconds under a pressure of 20 Pa. The air flow rate was 30 sccm (taken in from the atmosphere), and the output was 50 W. After plasma irradiation, air was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a CLPAH-100 aqueous solution (0.3 mass%) in an air atmosphere and left for 30 minutes. After washing with water, the CLPAH-100 aqueous solution containing the contact lens was transferred to a vial in air and heated at 121°C for 30 minutes. After thorough washing with water, the sample was placed in a contact lens storage solution (Seed Co., Ltd., Soft Care Pure) and further heated at 121°C for 30 minutes. After the heat treatment, the sample was thoroughly rinsed with water to remove any water adhering to the surface.

[0196] 12-2. Characterization (Water Contact Angle and Abrasion Test) Following the procedures described in 1-3-1 and 2-3-2, water contact angle measurements and abrasion tests were performed on multiple samples (n=6) obtained in Comparative Example 2. [Table 8] Table 8 shows the changes in water contact angle on the surfaces of the six samples in Comparative Example 2. After rinsing, the contact angle becomes superhydrophilic. After the abrasion test, the variation is relatively small, and the bonding of CLPAH-100 can be confirmed. However, after 4 days of exposure to air, some samples showed water contact angles of 93.1° and 94.6°, suggesting that CLPAH-100 is even more easily detached compared to the CO2 gas plasma. In fact, the average water contact angle after 4 days was 89.9°, which is 5.2° higher than in the case of CO2 plasma. This is likely because the oxygen in the air plasma reduced the Si· radicals and Si-CH2· radicals on the contact lens surface. Functional groups such as hydroxyl groups may be formed on some parts of the surface, but it is thought that such functional groups disappear from the contact lens surface over time, making it hydrophobic.

[0197] 13. Evaluation of hydrophilization by plasma polymerization method Patent document 9 proposes a method for forming a polymer film on the surface of a contact lens containing PDMS by plasma polymerization of hydrogen and tetrafluoroethylene, and further hydrophilizing the surface by oxygen plasma treatment. Patent document 10 also proposes a method for forming a hydrophilic coating layer by plasma polymerization using a mixed gas of argon and N-vinylpyrrolidone. Therefore, in this test, the hydrophilicity of lenses with a hydrophilic coating layer formed by plasma polymerization was evaluated and compared with lenses obtained by the plasma treatment method of the present invention.

[0198] [Comparative Example 3] 13-1. Preparation of lens samples A plasma generator (manufactured by Kai Semiconductor Co., Ltd., product name: YHS-DC100) was used, in which two 10 cm diameter circular plate electrodes were installed parallel to each other at a distance of 5 cm inside the chamber. The substrate prepared according to [Synthesis Example 2] was placed between the electrodes. N-vinylpyrrolidone vapor was introduced into the plasma generator chamber from a glass container containing liquid N-vinylpyrrolidone. At this time, the inner diameter of the plasma chamber was set to 120 mm, the inner diameter of the vapor introduction pipe to 4 mm, and the pressure of N-vinylpyrrolidone inside the chamber was increased by narrowing the exhaust gas flow path. With the exhaust gas flow path open, the N-vinylpyrrolidone flow rate could not exceed 12 sccm, and the pressure inside the chamber became 2 Pa, making it impossible to generate N-vinylpyrrolidone plasma. This is thought to be because N-vinylpyrrolidone has a large molecular weight, resulting in a small number of radicals that can be generated. On the other hand, when the exhaust gas flow path was completely closed, the vapor pressure could be adjusted to about 18 Pa, but in this case, the pressure inside the chamber increased to about 40 Pa due to plasma generation. This is thought to be because the N-vinylpyrrolidone in the plasma decomposed, and the number of decomposition product molecules at least doubled. Therefore, the exhaust gas flow path was slightly opened to reduce the pressure inside the chamber to 10 Pa. In this case, the inflow rate of N-vinylpyrrolidone vapor was almost 0 sccm. Plasma was generated at an output of 50 W, and the substrate was irradiated with the plasma for 30 seconds. After that, air was introduced to return the chamber to atmospheric pressure. The obtained sample was thoroughly rinsed with water to remove any water adhering to the surface. The obtained sample became slightly white when rinsed with water, but it quickly peeled off and became transparent when rubbed. This suggests that a carbon film formed on the surface, which peeled off when rubbed.

[0199] 13-2. Characteristic evaluation (water contact angle and abrasion resistance) Following the procedures described in 1-3-1 and 2-3-2, water contact angle measurements and abrasion tests were performed on multiple samples (n=6) obtained in Comparative Example 3. The results are shown below. [Table 9] Table 9 shows the changes in water contact angle on the surfaces of the six samples in Comparative Example 3. After rinsing, the contact angle was not superhydrophilic, suggesting the formation of a carbon film. This carbon film was mostly removed by abrasion tests, but the water contact angle remained stable. However, when the water contact angle was measured after 4 days of exposure to air, all values ​​were above 100°. As a result, it is thought that the carbon film did not cover the surface of the contact lens at all and peeled off over time, making it significantly hydrophobic. Furthermore, this result clearly indicates that no PVP film was formed on the surface of the contact lens. In plasma polymerization using N-vinylpyrrolidone as a gaseous raw material, not only is it difficult to introduce vapor into the chamber, but N-vinylpyrrolidone decomposes in the plasma, forming a carbon film that easily peels off due to frictional stress. In other words, a highly detachable carbon film is formed, which is completely different from the hydrophilic polymer coating layer of the present invention.

[0200] 14. Durability against abrasion and storage in the open air. This test evaluated the durability against repeated abrasion tests and exposure to air.

[0201] [Example 19] 14-1. Preparation of lens samples After subjecting the substrate to plasma treatment, the substrate surface was coated by immersion in a PVP aqueous solution. The plasma treatment was performed using a plasma generator in which two 20 cm diameter circular plate electrodes were placed parallel to each other with a 5 cm gap inside the chamber. The substrate prepared according to [Synthesis Example 2] was placed between the electrodes, the chamber was purged with vacuum, and then nitrogen gas was introduced and the sample was irradiated with plasma for 60 seconds under a pressure of 19 Pa. The nitrogen gas flow rate was 10 sccm and the output was 80 W. After plasma irradiation, nitrogen gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a PVP aqueous solution (0.2 mass%, weight-average molecular weight 360,000) under a nitrogen atmosphere and left for 30 minutes. After that, the sample was thoroughly rinsed with water to remove any water adhering to the surface.

[0202] 14-2. Characterization (Contact Angle and Abrasion Test) 14-2-1. Scratch Test The samples obtained in Example 19 (n=3) were wet with pure water, rubbed 200 times with nitrile rubber gloves, washed with pure water, and after wiping off the water adhering to the surface, the water contact angle was measured according to the procedure described in 1-3-1. 14-2-2. Hydrophilicity assessment after 2.3 days of exposure to air. To evaluate the stability of the hydrophilic polymer coating layer on the surface, the samples obtained in Example 19 (n=3) were wet with pure water, rubbed 200 times with nitrile rubber gloves, washed with pure water, and the water adhering to the surface was wiped off. After that, they were exposed to the air for 3 days, and the contact angle was measured according to the procedure described in 1-3-1. 14-2-3. Evaluation of hydrophilicity after water treatment To evaluate the resilience to the decrease in hydrophilicity after exposure testing, the samples (n=3) that had been exposed to air for three days were immersed in water for 10 minutes, the water adhering to the surface was wiped off, and then the contact angle was measured according to the procedure described in 1-3-1.

[0203] The results of each test are shown below. [Table 10]

[0204] The average contact angle of the sample obtained in Example 19 after 200 abrasion tests was 42.1°. This result indicates that the sample in Example 19 retained sufficient hydrophilicity even after 200 abrasion tests. The average contact angle of the sample obtained in Example 19 after being exposed to air for 3 days was 61.1°. Furthermore, the average contact angle of the sample obtained in Example 19 after being treated with water for 10 minutes was 57.4°. These results indicate that even after 200 abrasion tests and subsequent exposure to air, the hydrophilic polymer on the surface was retained, and hydrophilicity was restored to a certain extent by immersion in water. In this example, plasma treatment was performed by irradiating the sample with plasma for 60 seconds at an output of 80W. This is thought to have formed more radicals near the surface, and their reaction strengthened the bond between the hydrophilic polymer and the substrate, while also suppressing the diffusion of hydrophobic polymer onto the surface. In addition, it is thought that the entanglement between the hydrophilic polymer and the PDMS chain also makes it difficult for the hydrophilic polymer on the surface to peel off. Specifically, the Si· radicals formed near the surface of the sample eventually form Si-OH groups (silanol groups), and these silanol groups undergo dehydration condensation, introducing a cross-linked structure into the PDMS chain. When the silanol groups formed on the surface undergo dehydration condensation, if hydrophilic polymers are present nearby, the hydrophilic polymers become entangled with the cross-linked PDMS chains, which is thought to make it difficult for the hydrophilic polymers to peel off (see Figure 1 above).

[0205] 15. Durability against abrasion and long-term storage in the atmosphere This test evaluated the durability against repeated abrasion tests and prolonged exposure to the atmosphere. [Example 20] 15-1. Preparation of lens samples After subjecting the substrate to plasma treatment, the substrate surface was coated by immersion in a PVP aqueous solution. The plasma treatment was performed using a plasma generator in which two 20 cm diameter circular plate electrodes were placed parallel to each other with a 5 cm gap inside the chamber. The substrate prepared according to [Synthesis Example 2] was placed between the electrodes, the chamber was purged with vacuum, and then nitrogen gas was introduced and the sample was irradiated with plasma for 60 seconds under a pressure of 19 Pa. The nitrogen gas flow rate was 10 sccm and the output was 80 W. After plasma irradiation, nitrogen gas was introduced to return the chamber to atmospheric pressure, and the plasma-treated substrate was immersed in a PVP aqueous solution (0.2 mass%, weight-average molecular weight 360,000) under a nitrogen atmosphere and left for 30 minutes. Thereafter, in air, the contact lens was replaced with a vial containing a 1.0 wt% aqueous solution of polyphosphorylcholine (MPC: poly-2-methacryloyloxyethyl phosphorylcholine, weight-average molecular weight 100,000) and heated at 121°C for 30 minutes. After heat treatment, the sample was thoroughly rinsed with water to remove any water adhering to the surface.

[0206] 15-2. Characterization (Contact Angle and Abrasion Test) 15-2-1. Scratch Test The samples obtained in Example 20 (n=6) were wet with pure water, rubbed 200 times with nitrile rubber gloves, washed with pure water, and after wiping off the water adhering to the surface, the water contact angle was measured according to the procedure described in 1-3-1. 15-2 - Hydrophilicity assessment after 2.3 days of exposure to air To evaluate the stability of the hydrophilic polymer coating layer on the surface, the samples obtained in Example 20 (n=6) were wet with pure water, rubbed 200 times with nitrile rubber gloves, washed with pure water, and the water adhering to the surface was wiped off. After that, they were exposed to the air for 6 days, and the contact angle was measured according to the procedure described in 1-3-1. 15-2―3. Hydrophilicity evaluation after water treatment To evaluate the resilience to the decrease in hydrophilicity after the exposure test, the samples (n=6) that had been exposed to air for 6 days were immersed in water for 10 minutes, the water adhering to the surface was wiped off, and then the contact angle was measured according to the procedure described in 1-3-1. The results of each test are shown below. [Table 11] The average contact angle of the sample obtained in Example 20 after 200 abrasion tests was 45.5°. This result indicates that the sample in Example 20 retained sufficient hydrophilicity even after 200 abrasion tests. Furthermore, the average contact angle of the sample exposed to air for an additional 6 days after the abrasion treatment was 54.5°. In addition, the average contact angle of the sample immersed in water for 10 minutes after exposure to air was 49.8°. In the samples of this example, it is considered that the hydrophilic polymer on the surface was retained even after long-term exposure to air after the abrasion test.

Claims

1. An ophthalmic lens substrate comprising a (co)polymer having an alkyl group-containing polysiloxane structure, The substrate surface includes a single coating layer containing a hydrophilic polymer, The substrate and the hydrophilic polymer are bonded together at least via a C-C bond between the Si-C of the substrate and the C of the hydrophilic polymer. A soft eye lens in which the water contact angle of the surface of the coating layer is 70° or less.

2. Si in XPS measurement ２ｐ The soft eye lens according to claim 1, wherein the total width at half maximum of the peak derived from is 2.1 eV or less.

3. Si in XPS measurement ２ｐ The soft ophthalmic lens according to claim 1, wherein more than 60% of the peaks derived from are bonded to two oxygen atoms and two carbon atoms.

4. A soft ophthalmic lens according to any one of claims 1 to 3, wherein surface-adsorbed water is confirmed by XPS measurement under a water vapor pressure of 5 mbar.

5. The soft eye lens according to claim 4, wherein the water contact angle of the surface of the coating layer after 20 rub tests is 70° or less.

6. The soft eye lens according to claim 4, wherein the water contact angle of the surface of the coating layer after 200 rub tests is 50° or less.

7. The coating layer has a thickness of 1 nm to 5 μm, as described in any one of claims 1 to 6.

8. The soft ophthalmic lens according to any one of claims 1 to 7, wherein the substrate and the hydrophilic polymer are further bonded via an O-C bond between the Si-alkylene-O-O of the substrate and the C of the hydrophilic polymer.

9. The soft ophthalmic lens according to any one of claims 1 to 8, wherein the substrate and the hydrophilic polymer are further bonded via a Si-C bond between the Si of the substrate and the C of the hydrophilic polymer.

10. The hydrophilic polymer is water-soluble and has atoms having non-covalent pairs or double bonds, and the carbon adjacent to the atoms having non-covalent pairs or double bonds is bonded to the Si, Si-C carbon or Si-alkylene-O-O oxygen of the substrate, as described in any one of claims 1 to 9.

11. The soft ophthalmic lens according to any one of claims 1 to 10, wherein the substrate is obtained by polymerizing a (macro) monomer composition containing 20% ​​by mass or more of alkyl group-containing polysiloxane.

12. The hydrophilic polymer comprises polyvinylpyrrolidone, polyacrylic acid, ethylene glycol crosslinked polymer of polyacrylic acid, starch graft of polyacrylic acid, PEG, PEG-containing block copolymer, alginic acid, chondroitin sulfate, hyaluronic acid, pectin, hydroxyethyl cellulose, dextran, polyvinyl alcohol, polyethyleneimine, polyglutamic acid, or polyacrylamide, as described in claim 10.

13. A soft ophthalmic lens according to any one of claims 1 to 12, having an oxygen permeability (Dk value) of 150 or more.

14. A method for producing a soft ophthalmic lens having a single coating layer containing a hydrophilic polymer on an ophthalmic lens substrate containing an (co)polymer having an alkyl group-containing polysiloxane structure, The process involves subjecting the substrate to plasma treatment in an inert gas atmosphere to form radicals on the surface of the substrate, including at least Si-alkyl radicals. The process involves immersing the substrate in an aqueous solution of a hydrophilic polymer containing a structure that can resonate when a radical is formed on a carbon atom, while retaining the Si-alkyl radical, thereby causing a radical transition to the hydrophilic polymer, and forming a coating layer containing the hydrophilic polymer by bonding the hydrophilic polymer to the substrate through the radical generated in the hydrophilic polymer. A method for manufacturing soft ophthalmic lenses, including [the specified component].

15. The method according to claim 14, wherein the radical includes a Si radical and a Si-alkyl radical.

16. The method according to claim 15, wherein the radical further comprises a Si-alkylene-O-O radical.

17. The method according to any one of claims 14 to 16, wherein immediately after the plasma treatment, at least 10% of the carbon bonded to the Si present on the surface of the substrate are radicals.

18. The method according to any one of claims 14 to 17, wherein immediately after the plasma treatment, at least 20% of the alkyl group-containing polysiloxane units present on the substrate surface are radicals.

19. The method according to any one of claims 14 to 18, wherein the plasma is generated at a low frequency of 50 Hz or 60 kHz and a power of 10 to 150 W.

20. The method according to claim 19, wherein the inert gas is introduced into the reaction chamber at a gas pressure of 2 Pa to 30 Pa and a rate of 1 sccm to 100 sccm.

21. The method according to claim 19 or 20, wherein the plasma treatment is performed for 5 seconds to 2 minutes.

22. The method according to claim 21, wherein plasma is generated with a power of 60 to 150 W, and the plasma treatment is performed for 50 seconds to 2 minutes.

23. The method according to any one of claims 14 to 18, wherein plasma is generated by glow discharge at 3 to 30 mA.

24. The method according to any one of claims 14 to 23, wherein the substrate is obtained by polymerizing a (macro) monomer composition containing 20% ​​by mass or more of alkyl group-containing polysiloxane.

25. The method according to any one of claims 14 to 24, wherein the hydrophilic polymer is water-soluble and has an alkyl group, an alkylene group, or a methine group and an atom or double bond having a lone pair of electrons, and the carbon of the alkyl group, alkylene group, or methine group is adjacent to the atom or double bond having a lone pair of electrons.

26. The method according to claim 25, wherein the hydrophilic polymer comprises polyvinylpyrrolidone, polyacrylic acid, ethylene glycol crosslinked polymer of polyacrylic acid, starch graft of polyacrylic acid, PEG, PEG-containing block copolymer, alginic acid, chondroitin sulfate, hyaluronic acid, pectin, hydroxyethyl cellulose, dextran, polyvinyl alcohol, polyethyleneimine, polyglutamic acid, or polyacrylamide.

27. The method according to any one of claims 14 to 26, wherein the substrate subjected to the plasma treatment is held in an oxygen-containing atmosphere for a time of 10 seconds or less.

28. The method according to any one of claims 14 to 27, wherein the substrate on which the radicals are formed is immersed in an aqueous solution of the hydrophilic polymer within 10 seconds after the plasma treatment.

29. The method according to any one of claims 14 to 28, wherein the substrate on which the radicals are formed is immersed in an aqueous solution of the hydrophilic polymer at a temperature of 10 to 30°C for 30 minutes to 1 hour.

30. The method according to claim 29, wherein the substrate on which the radicals have been formed is further immersed in an aqueous solution of the hydrophilic polymer at a temperature of 80 to 135°C for 20 minutes to 2 hours for heat treatment.

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