Addition type polymer and silicone hydrogel lens material

Abstract

This addition type polymer is added to a silicone hydrogel to improve tensile break strength and toughness of the silicone hydrogel and contains a benzotriazole skeleton without containing polymerizable groups.

Description

Additive-based polymer and silicone hydrogel lens materials

[0001] The present invention relates to additive polymer and silicone hydrogel lens materials.

[0002] Conventionally, silicone hydrogel lens materials have been proposed that contain copolymer components including a compound A having, via a urethane bond, an ethylenically unsaturated group and a group containing a polydimethylsiloxane structure, an alkoxy group-containing acrylate B, and a phenyl alkyl acrylate or phenoxy alkyl acrylate C (see, for example, Patent Document 1). This contact lens material is transparent, has low adhesiveness, is safe as it does not adhere to the cornea when worn, is easy to handle, and has an appropriate balance of strength and flexibility or elasticity, resulting in excellent shape stability.

[0003] Japanese Patent Application Laid-Open No. 2005-089654

[0004] However, although the silicone hydrogel lens material of Patent Document 1 described above is said to achieve an appropriate balance between strength and flexibility or elasticity by combining Compounds A to C, this is still not sufficient, and there is a need to further improve mechanical properties such as tensile breaking strength and toughness.

[0005] The present invention has been made in consideration of these problems, and its main object is to provide an additive polymer and a silicone hydrogel lens material that can further improve the mechanical properties of silicone hydrogel lens materials.

[0006] As a result of extensive research to achieve the above-mentioned object, the inventors discovered that adding an additive polymer containing a benzotriazole skeleton but no polymerizable group to a silicone hydrogel in a predetermined range can further improve the mechanical properties, leading to the completion of the present invention.

[0007] That is, the additive polymer of the present invention is an additive polymer that is added to a silicone hydrogel to improve the tensile breaking strength and toughness of the silicone hydrogel, and contains a benzotriazole skeleton but does not have a polymerizable group.

[0008] The silicone hydrogel lens material of the present invention comprises a silicone hydrogel base material and the additive polymer, wherein the additive polymer is contained in an amount of 20 parts by weight or less per 100 parts by weight of the base material.

[0009] The additive polymer and silicone hydrogel lens material of the present invention can further improve mechanical properties. The reason for this effect is presumed to be as follows. For example, it is presumed that mechanical properties such as tensile breaking strength and toughness are improved by physically incorporating the additive polymer containing a benzotriazole skeleton without a polymerizable group into the structure of the silicone hydrogel base material.

[0010] <Additive Polymer> The additive polymer disclosed in this embodiment is added to a silicone hydrogel to improve the tensile breaking strength and toughness of the silicone hydrogel. It contains a benzotriazole skeleton but does not have a polymerizable group. Here, the polymerizable group that the additive polymer does not have refers to groups that undergo addition polymerization, such as vinyl groups, acryloyl groups, and methacryloyl groups, and does not include hydroxyl groups, aromatic rings, or heterocycles. Acrylates containing acryloyl groups and methacrylates containing methacryloyl groups are collectively referred to as "(meth)acrylates" below. For ease of explanation, the constituent moieties contained in the polymer will be identified by the name of the monomer, and the monomers exemplified in the description of the polymer structure will be those in which the polymerizable group is bonded to other constituent moieties. For example, in the description of the polymer structure, a "(meth)acrylate" will be exemplified as a "(meth)acrylate structure" in the polymer, which is a structure in which other constituent moieties are bonded (polymerized) to the double bond of the (meth)acrylate.

[0011] This additive polymer preferably has the same constituent moiety as the moiety constituting the silicone hydrogel substrate. Having such a constituent moiety can further enhance compatibility with the silicone hydrogel monomer. Examples of such a constituent moiety include a silicone moiety having a siloxane bond, an amide moiety having an amide bond, an ether moiety having an ether bond, and an ester moiety having an ester bond. This constituent moiety may include one or more of the structures of the monomers of the substrate described below, such as the structures of acrylamide-based hydrophilic monomers such as N-vinyl-2-pyrrolidone (N-VP), 1-methyl-3-methylene-2-pyrrolidinone (N-MMP), and N,N-dimethylacrylamide (DMAA). Of these, this constituent moiety is preferably a silicone moiety. For example, the additive polymer may have a structure in which a triazole moiety A containing a benzotriazole skeleton and a silicone moiety B having a siloxane bond are bonded by a carbon chain. This silicone moiety B may be the same as the moiety constituting the silicone hydrogel substrate. The benzotriazole moiety A may have a structure in which a benzotriazole skeleton is bonded to a carbon chain via an aromatic ring and a bonding chain. The aromatic ring may be a benzene ring having one or more substituents, and the substituents may be, for example, one or more of a hydroxyl group, an alkyl group having 6 or less carbon atoms, or an acyl group having 6 or less carbon atoms. The bonding chain may be an alkyl chain having 6 or less carbon atoms, and the bonding chain may include an ester bond.

[0012] The silicone moiety B may have, for example, a silicone-containing alkyl(meth)acrylate structure. This silicone moiety B may be, for example, trimethylsiloxydimethylsilylmethyl(meth)acrylate, trimethylsiloxydimethylsilylpropyl(meth)acrylate, methylbis(trimethylsiloxy)silylpropyl(meth)acrylate, tris(trimethylsiloxy)silylpropyl(meth)acrylate, mono[methylbis(trimethylsiloxy)siloxy]bis(trimethylsiloxy)silylpropyl(meth)acrylate, tris[methylbis(trimethylsiloxy)siloxy]silylpropyl(meth)acrylate, methylbis(trimethylsiloxy)silylpropylglyceryl(meth)acrylate, tris(trimethylsiloxy)silylpropylglyceryl(meth)acrylate, mono[methylbis(trimethylsiloxy)siloxy]silylpropyl(meth)acrylate, Examples of suitable methylsiloxysilyl esters include bis(trimethylsiloxy)silylpropyl glyceryl (meth)acrylate, trimethylsilylethyl tetramethyldisiloxypropyl glyceryl (meth)acrylate, trimethylsilylmethyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, trimethylsilylpropyl glyceryl (meth)acrylate, trimethylsiloxydimethylsilylpropyl glyceryl (meth)acrylate, methylbis(trimethylsiloxy)silylethyl tetramethyldisiloxymethyl (meth)acrylate, tetramethyltriisopropylcyclotetrasiloxanylpropyl (meth)acrylate, and tetramethyltriisopropylcyclotetrasiloxybis(trimethylsiloxy)silylpropyl (meth)acrylate. Among these, tris(trimethylsiloxy)silylpropyl methacrylate (TRIS) is preferred from the viewpoint of easy availability.

[0013] The additive polymer preferably has a structure shown in formula (1): In formula (1), m and n are integers, and R 1 , R 2 and R 3 is any group, and R 1 and R 3may be different groups from or may be the same group, but it is more preferable that they are the same group. 2 R may be one or more of hydrogen, a hydroxyl group, an alkyl group, and an acyl group. The alkyl group and the acyl group preferably have 6 or less carbon atoms. 1 and R 3 represents a linking chain, and examples thereof include alkyl chains having 6 or less carbon atoms, and this linking chain may contain an ester bond. Furthermore, in formula (1), the triazole moiety A and the silicone moiety B may be linked to the carbon chain in any order. In formula (1), the carbon chain linking the triazole moiety A and the silicone moiety B may be an alkyl chain having 1 to 6 carbon atoms. More specifically, the additive polymer preferably has a structure shown in formula (2). In formulas (1) and (2), the triazole moiety A and the silicone moiety B may be linked to the carbon chain in any order, and two or more triazole moieties A may be adjacent to each other, or two or more silicone moieties B may be adjacent to each other. The molar ratio m / n of the triazole moiety A (m) to the silicone moiety B (n) having a siloxane bond is preferably in the range of 1 / 1 to 4 / 1. Within this range, the tensile breaking strength and toughness of the silicone hydrogel can be further improved. This molar ratio is more preferably in the range of 2 / 1 to 3.5 / 1.

[0014]

[0015]

[0016] The additive polymer is preferably added to the silicone hydrogel lens material in an amount greater than 0 parts by weight and not greater than 20 parts by weight per 100 parts by weight of the silicone hydrogel base material. This range allows for increased tensile breaking strength and toughness of the silicone hydrogel. The content of the additive polymer is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, and even more preferably 0.5 parts by weight or more. The content of the additive polymer is preferably 15 parts by weight or less, more preferably 10 parts by weight or less, and even more preferably 5 parts by weight or less. When added to a silicone hydrogel, the additive polymer may improve the tensile breaking strength by 10% or more and the toughness by 15% or more compared to a silicone hydrogel without the additive polymer. The effect of adding the additive polymer may be an improvement in tensile breaking strength of 50% or more, or even 100% or more. The effect of adding this additive polymer may be to improve toughness by 50% or more, or may be to improve toughness by 100% or more.

[0017] Next, a method for producing an additive polymer will be described. This production method may include, for example, a polymerization step of polymerizing raw material monomers containing at least a monomer having a benzotriazole skeleton. The raw material monomers may include a monomer having a moiety that constitutes the base material of a silicone hydrogel. Examples of monomers that constitute the base material include silicone monomers having a siloxane bond, a monomer having an amide bond, a monomer having an ether bond, and a monomer having an ester bond, among which silicone monomers are preferred. As this raw material monomer, a monomer having the structure described above for the additive polymer can be used. The blending ratio of the raw material monomers is preferably such that the molar ratio m / n of the polymerization product of, for example, a monomer (m) having a benzotriazole skeleton and a monomer (n) having the same moiety as the base material is 1 / 1 to 4 / 1, more preferably 2 / 1 to 3.5 / 1. Examples of polymerization methods include radical polymerization using a radical polymerization initiator. Examples of radical polymerization initiators include azo compounds, peroxide compounds, and dihalogens. Examples of azo compounds include azobisisobutyronitrile (AIBN) and 1,1'-azobis(cyclohexanecarbonitrile) (ABCN). Examples of peroxide compounds include benzoyl peroxide and methyl ethyl ketone peroxide. Examples of dihalogens include chlorine molecules. The amount of polymerization initiator used is preferably 0.001 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of raw material monomers.

[0018] <Silicone Hydrogel Lens Material> The silicone hydrogel lens material disclosed in this embodiment comprises a silicone hydrogel substrate and the additive polymer described above. The additive polymer is contained in an amount greater than 0 parts by weight and less than 20 parts by weight per 100 parts by weight of the substrate. The additive polymer content is preferably at least 0.1 parts by weight, more preferably at least 0.2 parts by weight, and even more preferably at least 0.5 parts by weight per 100 parts by weight of the substrate. The additive polymer content is preferably at most 15 parts by weight, even more preferably at most 10 parts by weight per 100 parts by weight of the substrate. This silicone hydrogel lens material may have a tensile breaking strength that is at least 10% higher and a toughness that is at least 15% higher than that of a silicone hydrogel without the additive polymer. This silicone hydrogel lens material may have a tensile breaking strength that is at least 50% higher, or even at least 100% higher, than that of a silicone hydrogel without the additive polymer. Furthermore, the silicone hydrogel lens material may exhibit a toughness improvement of at least 50%, or even 100%, compared to a silicone hydrogel without the additive polymer, and this improvement can be adjusted by adjusting the structure and content of the additive polymer.

[0019] The substrate of the silicone hydrogel lens material may contain a silicone moiety having a siloxane bond, an amide moiety having an amide bond, an ether moiety having an ether bond, an ester moiety having an ester bond, etc. These constituent moieties may have a structure formed by polymerization of a silicone macromer or silicone monomer having a siloxane bond, a monomer having an amide bond, a monomer having an ether bond, a monomer having an ester bond, etc. Each monomer has a polymerization group such as a vinyl group, an acryloyl group, or a methacryloyl group, and the silicone hydrogel substrate has a structure formed by polymerization of these polymerization groups, such as a silicone macromer structure or a silicone monomer structure.

[0020] The silicone macromer structure may be, for example, a structure containing at least a urethane bond, an ether bond, an ester bond, and a polydimethylsiloxane moiety. This silicone macromer may have a structure represented by formula (3). In this silicone macromer structure, a is an integer of 30 or more and 50 or less. R 4 , R 5 R represents one or more alkyl groups and halogen-substituted alkyl groups, and each of the one or more may be different groups or the same group. 4 , R 5 has preferably 6 or less carbon atoms. Examples of halogen substituents include chlorine and fluorine, with fluorine being preferred. Specific examples of this silicone macromer structure include structures of formulas (4) and (5). The content of the silicone macromer is preferably in the range of 5% by mass or more and 40% by mass or less with respect to the entire substrate. This range is preferred because it can further increase oxygen permeability and flexibility while also further improving polymerizability.

[0021]

[0022]

[0023] Examples of the silicone monomer structure include one or more of the monomers described above for the silicone moiety B. The content of this silicone monomer structure is preferably in the range of 10% by mass to 40% by mass of the entire substrate. This range is preferable because it can further increase oxygen permeability and flexibility while also further improving polymerizability.

[0024] The monomer structure having an amide bond may be, for example, a structure obtained by polymerizing an amide compound (monomer) having a polymerizable group. Examples of such monomers include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N,N-diethylaminopropyl(meth)acrylamide. Of these, N,N-dimethylacrylamide (DMAA) is preferred. Furthermore, the hydrophilic structure may include, for example, unsaturated carboxylic acids such as methacrylic acid and acrylic acid, acrylic-substituted alcohols such as 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate, vinyl lactams such as 1-methyl-3-methylene-2-pyrrolidinone (N-MMP) and N-vinyl-2-pyrrolidone (N-VP), and (meth)acrylates having a polyethylene glycol moiety. The content of such monomers is preferably 40% by mass or less relative to the entire substrate. In this range, it is possible to further prevent the moisture content from becoming too high, and to further prevent the dry feeling from being affected. This content is preferably 10% by mass or more. When this content is 10% by mass or more, sufficient hydrophilicity can be obtained.

[0025] Examples of monomer structures having an ether bond include structures such as methoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and hydroxydiethylene glycol (meth)acrylate. Of these, methoxyethyl acrylate (2-MTA) is preferred. The content of this monomer is preferably in the range of 10% by mass or more and 40% by mass or less based on the entire substrate.

[0026] In addition to the substrate, this silicone hydrogel lens material may further include a crosslinked structure formed by the polymerization of a crosslinker having multiple polymerization groups, or a dye structure formed by the polymerization of a dye having a polymerization group. Examples of crosslinked structures include allyl (meth)acrylate, vinyl (meth)acrylate, 4-vinylbenzyl (meth)acrylate, 3-vinylbenzyl (meth)acrylate, (meth)acryloyloxyethyl (meth)acrylate, ethylene glycol di(meth)acrylate, diallyl adipate, diethylene glycol di(meth)acrylate, diethylene glycol diallyl ether, and triethylene glycol di(meth)acrylate. Of these, allyl methacrylate (AMA) and ethylene glycol dimethacrylate (EDMA) are preferred. The content of this crosslinked structure is preferably in the range of 0.05 to 1 part by weight per 100 parts by weight of the entire substrate.

[0027] Examples of the dye structure include phthalocyanine-based polymerizable dyes such as phthalocyanine-containing polymethacrylate esters, azo-based polymerizable dyes such as 1-phenylazo-4-(meth)acryloyloxynaphthalene, anthraquinone-based polymerizable dyes such as 1,5-bis((meth)acryloylamino)-9,10-anthraquinone, 1,4-bis(4-(2-methacryloxyethyl))phenylaminoanthraquinone (Reactive Blue 246), and 1,4-bis((2-hydroxyethyl)amino)-9,10-anthracenedione (Reactive Blue 247), and nitro-based polymerizable dyes such as o-nitroanilinomethyl(meth)acrylate. Of these, phthalocyanine-based polymerizable dyes are preferred. Examples of phthalocyanine-based polymerizable dyes include (meth)acryloylated tetraamino copper phthalocyanine and (meth)acryloylated (dodecanoylated) tetraamino copper phthalocyanine. Furthermore, benzophenone-based polymerizable UV-absorbing dyes such as 2,4-dihydroxy-3(p-styreneazo)benzophenone, and benzoic acid-based polymerizable UV-absorbing dyes such as 2-hydroxy-4-(p-styreneazo)benzoate phenyl may also be included. The content of this dye structure is preferably in the range of 0.05 parts by mass or more and 1 part by mass or less per 100 parts by mass of the entire substrate.

[0028] This silicone hydrogel lens material preferably has a water content in the range of 40% to 70% by weight, more preferably 60% or less, and even more preferably 50% or less. A water content of 40% or more can improve the water wettability of the lens material. A water content of 70% or less can further enhance shape retention.

[0029] Silicone hydrogel lens materials preferably have a refractive index of 1.2 or higher, more preferably 1.4 or higher, with higher refractive indices being preferred for ophthalmic lenses.

[0030] Silicone hydrogel lens materials preferably have an oxygen permeability coefficient (Dk) of 20 or more, more preferably 50 or more. The higher the oxygen permeability coefficient, the more suitable it is for ophthalmic lens applications. The Dk value is expressed in units of 10 -11 (cm 2 / sec)·(mLO2 / (mL·mmHg)).

[0031] Silicone hydrogel lens materials preferably have a luminous transmittance of 95% or more, more preferably 96% or more. Higher luminous transmittance is preferred for ophthalmic lenses.

[0032] Next, a method for producing this silicone hydrogel lens material will be described. This production method may include, for example, a polymerization step of mixing a base monomer, which serves as the base material of the silicone hydrogel, with an additive polymer that does not have a polymerizable group, and polymerizing the base monomer. The base monomer may include a silicone compound having a polymerizable group and a siloxane bond, an amide compound having a polymerizable group and an amide bond, or an ether compound having a polymerizable group and an ether bond. The blending ratio of each raw material component may be within the ranges described above for the silicone hydrogel lens material.

[0033] Examples of silicone compounds include the silicone macromer and silicone monomer described above. For example, the silicone macromer may be a compound containing at least a urethane bond, an ether bond, an ester bond, and a polydimethylsiloxane moiety. This silicone macromer may have a structure represented by formula (6). Specific examples of this silicone macromer include formulas (7) and (8). Examples of silicone monomers include monomers having any of the structures described above for the silicone moiety B. Of these, tris(trimethylsiloxy)silylpropyl methacrylate (TRIS) is preferred.

[0034]

[0035]

[0036] Examples of the amide compound include monomers having any of the structures described above for the monomer structure having an amide bond. Of these, N,N-dimethylacrylamide (DMAA) is preferred. Furthermore, examples of hydrophilic monomers that may be used include unsaturated carboxylic acids such as methacrylic acid and acrylic acid, acrylic-substituted alcohols such as 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate, vinyl lactams such as 1-methyl-3-methylene-2-pyrrolidinone and N-vinylpyrrolidone, and (meth)acrylates having a polyethylene glycol moiety.

[0037] Examples of the ether compound include monomers having any of the structures described above for the monomer structure having an ether bond, among which methoxyethyl acrylate (2-MTA) is preferred.

[0038] In addition, in this polymerization step, in addition to the base monomer, a crosslinking agent, a polymerizable dye, a polymerization initiator, etc. may be further added. As the crosslinking agent, a compound having any of the structures described above in the crosslinked structure section may be used. Furthermore, as the polymerizable dye, a compound having any of the structures described above in the dye structure section may be used. In addition, in this polymerization step, non-polymerizable water-soluble organic solvents, surfactants, cooling agents, thickeners, etc. may be used as additives.

[0039] The polymerization process for silicone hydrogel lens materials may involve thermal polymerization or photopolymerization. Examples of polymerization initiators that can be used include thermal polymerization initiators and photopolymerization initiators. For example, when the additive polymer is present in a relatively high proportion, such as 5 parts by mass or more per 100 parts by mass of the entire base material, it is preferable to use a thermal polymerization initiator. When the additive polymer is present in a relatively low proportion, such as less than 5 parts by mass, it is preferable to use a photopolymerization initiator. Examples of thermal polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis-(2,4-dimethylvaleronitrile) (V-65), benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, t-butyl peroxyhexanoate, and 3,5,5-trimethylhexanoyl peroxide. These thermal polymerization initiators can be used alone or in combination. Examples of photopolymerization initiators include phosphine oxide-based photopolymerization initiators, benzoin-based photopolymerization initiators, phenone-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators. Examples of phosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of benzoin-based photopolymerization initiators include methyl orthobenzoyl benzoate and methyl benzoyl formate. Examples of phenone-based photopolymerization initiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one (HMPPO) and p-isopropyl-α-hydroxyisobutylphenone. Examples of thioxanthone-based photopolymerization initiators include 2-chlorothioxanthone and 2-methylthioxanthone. These photopolymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.001 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the base monomer.

[0040] In this polymerization step, the raw material composition can be cured by a mold method. When the raw material composition is polymerized by heating, a mold corresponding to the shape of the desired ophthalmic lens material is filled with the raw material composition containing the thermal polymerization initiator, and the mold is then heated to polymerize. The mold may be made of any material that can withstand the temperatures required for polymerization and curing. When the raw material composition is polymerized by irradiating it with light, a mold corresponding to the shape of the desired ophthalmic lens material is filled with the raw material composition containing the photopolymerization initiator, and the mold is then irradiated with light to polymerize. The material of the mold used for polymerization by light irradiation is not particularly limited as long as it is a material that can transmit the light required for polymerization and curing, and is preferably a general-purpose resin such as polypropylene, polystyrene, nylon, or polyester, or may be glass.

[0041] In the additive polymer and silicone hydrogel lens material of the present embodiment described above, for example, the additive polymer containing a benzotriazole skeleton without a polymerizable group is physically incorporated into the structure of the silicone hydrogel substrate, which is thought to improve mechanical properties such as tensile breaking strength and toughness. Furthermore, this benzotriazole skeleton has a low acid dissociation constant (pKa), and is thought to interact with surrounding amide bonds in the lens material, thereby reinforcing the mechanical strength.

[0042] It goes without saying that the present invention is not limited to the above-described embodiment, and can be embodied in various forms as long as they fall within the technical scope of the present invention.

[0043] The following experimental examples are specific examples of the silicone hydrogel lens material of the present invention. Experimental Examples 5 to 10 and 12 correspond to working examples of the present invention, while Experimental Examples 1 to 4 and 11 correspond to comparative examples. It goes without saying that the present invention is in no way limited to the following examples, and that various embodiments can be implemented as long as they fall within the technical scope of the present invention.

[0044] [Components Used] The abbreviations of the compounds used in the examples are shown below. <Base material> Silicone macromer: Silicone compound represented by formula (7) TRIS: Tris(trimethylsiloxy)silylpropyl methacrylate N-VP: N-vinyl-2-pyrrolidone N-MMP: 1-methyl-3-methylene-2-pyrrolidinone 2-MTA: 2-methoxyethyl acrylate DMAA: N,N-dimethylacrylamide <Crosslinking agent> AMA: Allyl methacrylate EDMA: Ethylene glycol dimethacrylate <Polymerization initiator> TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide V-65: 2,2'-azobis-(2,4-dimethylvaleronitrile) <Dye> PCPMA: Phthalocyanine-containing polymethacrylate ester RB-247: 1,4-bis((2-hydroxyethyl)amino)-9,10-anthracenedione <Monomer for additive-type polymer> Benz-M: 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole <Comparative polymer> TMSSt: tris(trimethylsiloxy)silylstyrene

[0045] [Synthesis of Additive Polymers 1-4] 7 g of Benz-M and 5 g of TRIS (charge molar ratio = 1.84:1) were weighed into a 200 mL three-neck flask (reaction vessel) and dissolved in 50 mL of toluene. The reaction vessel was placed in an oil bath heated to 80 °C, and after confirming that the internal liquid temperature was 80 °C, 0.60 g of azobisisobutyronitrile (AIBN) dissolved in 15 mL of toluene was quickly added to initiate the reaction. After 24 h, the reaction vessel was removed from the oil bath and cooled to room temperature. The reaction solution was then added dropwise to 1 L of stirred methanol in a beaker using a dropping funnel at a rate of 2 drops / second to precipitate the polymer. The resulting solution was filtered using a glass funnel with suction, washed twice with 100 mL of methanol, and dried in a vacuum oven at 50 °C for 1 hour, yielding approximately 6 g of additive polymer 1 as a white solid. Furthermore, additive polymer 2 was obtained through the same process as above using a monomer in which the phenolic OH group of Benz-M was acetylated. Furthermore, additive polymers 3 and 4 were obtained using monomers in which the ratio of Benz-M to TRIS was varied. The molar ratio of triazole moieties (Benz-M moieties) to silicone moieties (TRIS moieties) in additive polymers 1 and 2 was 2.7:1, and the content of triazole moieties relative to the total was 73% by mass. The molar ratios of triazole moieties (Benz-M moieties) to silicone moieties (TRIS moieties) in additive polymers 3 and 4 were 3.1:1 and 2.2:1, respectively.

[0046] [Synthesis of Comparative Polymers 1 to 3] Comparative polymers were prepared in the same manner as the additive polymers using TRIS, N-VP, DMAA, and TMSSt as monomers in the charge mass ratios shown in Table 1. Table 1 shows the composition, weight average molecular weight Mw, number average molecular weight Mn, and Mw / Mn of the prepared polymers.

[0047]

[0048] [Formulation and Polymerization of Silicone Hydrogel] The polymer obtained above was dissolved in advance in a monomer that is highly compatible with and used in a large amount in a contact lens formulation solution, and the monomers shown in Table 2 were mixed in the appropriate order to prepare a contact lens formulation solution. To prevent moisture absorption by the monomers during weighing, the monomers were weighed in order, starting with the hydrophobic monomer. The polymerization initiator used was selected from thermal polymerization initiators (azo-based: V-65) and photopolymerization initiators (phosphine oxide-based: TPO). For compositions containing a large amount of benzotriazole-based additive polymer in the formulation solution (Experimental Examples 6 to 8), thermal polymerization was carried out using a thermal polymerization initiator, while for compositions containing a small amount of additive polymer (approximately 1% of the formulation: Experimental Examples 1 to 5, 9 to 12), a photopolymerization initiator was selected. The prepared formulation solution was poured into a lens mold. Thermal polymerization was carried out for 2 hours in a dryer set at 80°C. Photopolymerization was carried out using a light source containing blue light at an appropriate illuminance (illuminance 2.5 to 3.5 mW / cm). 2 ) and polymerization was carried out by irradiation for 20 minutes.

[0049] [Hydration Treatment] After demolding, the resulting polymer was subjected to plasma irradiation (RF power 50 W, pressure 100 Pa) for 120 seconds in a carbon dioxide atmosphere. The polymer was immersed in distilled water to absorb water and subjected to hydration treatment, followed by heat sterilization in an autoclave (2 atmospheres, 121°C, 20 minutes) to obtain contact lenses. The resulting silicone hydrogel contact lenses were designated Experimental Examples 1 to 12. The blending ratios for Experimental Examples 1 to 12 are summarized in Table 2.

[0050]

[0051] (Strength Measurement) A tensile test was carried out on lens fragments (thickness 0.1 mm, width 1.8 mm, fixture distance 6.0 mm) in ISO physiological saline at 20°C using an Autograph AG-IS tensile tester manufactured by Shimadzu Corporation. The test was carried out on five or more lenses per lot, and the tensile breaking strength was determined from the maximum load until breakage and the thickness and width of the lens fragment, and the toughness was determined from the breakage energy, thickness and width of the lens fragment, and fixture distance.

[0052] (Water Content) The water content (mass %) of the lens was measured in ISO physiological saline at a temperature of 20°C according to the following formula, where W is the lens mass (g) in an equilibrium state after conditioning, and W0 is the lens mass (g) dried for 16 hours in a dryer at 105°C. Water Content (mass %) = (W - W0) / W x 100

[0053] (Refractive Index) The refractive index of the mercury-e line was measured in ISO physiological saline at a temperature of 20° C. using a refractometer 2T manufactured by Atago Co., Ltd.

[0054] (Dk (oxygen permeability) value) The oxygen permeability coefficient of the lens was measured in ISO physiological saline at 35°C using a Seikaken film oxygen permeability meter manufactured by Rika Seiki Kogyo Co., Ltd. according to the electrode method described in ISO 18369-4 (2006). The unit of Dk value is 10 -11 (cm 2 / sec)·(mLO2 / (mL·mmHg)).

[0055] (Luminous transmittance) The luminous transmittance of the lens in ISO physiological saline was measured using a UV-2550 manufactured by Shimadzu Corporation. The measurement conditions were transmittance (0-100%), slit 5 nm, and measurement wavelength 780 to 380 nm, and the lens holder was set in a quartz cell to measure the light transmission spectrum. The luminous transmittance (780 to 380 nm) was calculated by data processing.

[0056] (Results and Discussion) The water content (mass%), refractive index, Dk value, and luminous transmittance (%) of Silicone Hydrogels 1 and 2 (Experimental Examples 1 and 11) are summarized in Table 3. Both Silicone Hydrogels 1 and 2 had suitable water content and refractive index, and exhibited high oxygen permeability and luminous transmittance. Tables 4 to 6 also summarize the structure of each experimental example, the amount of polymer added (mass%), tensile breaking strength (MPa), the percentage change (%) relative to the control (Experimental Examples 1 and 11) to which no polymer was added, toughness (MPa), and the percentage change (%) relative to the control. The strains of Experimental Examples 1, 9, and 10 were 500%, 563%, and 515%, respectively, and the moduli of elasticity were 0.23 MPa, 0.24 MPa, and 0.25 MPa, respectively. As shown in Table 4, Experimental Examples 2 to 4, to which Comparative Polymers 1 to 3 were added, exhibited lower tensile breaking strength and toughness than Experimental Example 1, to which no polymer was added. In contrast, Experimental Examples 5 to 8, in which additive polymers 1 and 2 were added, showed dramatic improvements in tensile breaking strength and toughness, with a change rate of 50% or more compared to Experimental Example 1, in which no polymer was added. Furthermore, Experimental Examples 9 and 10, in which additive polymers 3 and 4 were added, showed improvements in tensile breaking strength and toughness, with a change rate of 15% or more compared to Experimental Example 1, in which no polymer was added. The results of Experimental Examples 5 to 10 demonstrated that tensile breaking strength and toughness were improved even when the compounding ratio of Benz-M to TRIS in the additive polymer was different. In particular, it was found that in the additive polymer, the molar ratio m / n of the triazole moiety A(m) to the silicone moiety B(n) having a siloxane bond is preferably in the range of 1 / 1 to 4 / 1, with a range of 2 / 1 to 3.5 / 1 being more preferable. The results of Experimental Examples 5 to 12 demonstrated that the effect of adding an additive polymer was observed in silicone hydrogels 1 and 2, i.e., even when the hydrogel compositions were different. In particular, it was found that the amount of additive polymers 1 to 4 added was more preferably in the range of 10 parts by mass or less per 100 parts by mass of the silicone hydrogel base material.

[0057] The compatibility of additive polymers with silicone hydrogels was also investigated. Benz-M homopolymer was mixed as an additive polymer into a mixture of silicone hydrogel 3 monomers. The results showed that this homopolymer did not dissolve in the mixture. Therefore, it was found that it is preferable for the additive polymer to have the same constituent parts as the constituent parts of the silicone hydrogel matrix.

[0058]

[0059]

[0060]

[0061]

[0062] The additive polymers of the present invention can be used in silicone gel contact lens applications.

Claims

1. An additive polymer that is added to a silicone hydrogel to improve the tensile breaking strength and toughness of the silicone hydrogel, An additive type polymer that contains a benzotriazole skeleton and has no polymerizable groups.

2. 2. The additive-type polymer according to claim 1, having a structure in which a triazole moiety containing the benzotriazole skeleton and a silicone moiety having a siloxane bond are bonded via a carbon chain.

3. 3. The additive polymer of claim 1 having the structure shown in formula (1). 【Chemistry 1】

4. The additive polymer according to claim 1 or 2, having the same constituent portion as the constituent portion of the base material of the silicone hydrogel.

5. A silicone hydrogel base material; and the additive polymer according to claim 1 or 2, The additive polymer is contained in an amount of 20 parts by mass or less per 100 parts by mass of the base material. Silicone hydrogel lens material.

6. The silicone hydrogel lens material of claim 5 , wherein the silicone hydrogel base material has the structure of formula (2): 【Chemistry 2】

7. The silicone hydrogel lens material according to claim 5, wherein the silicone hydrogel lens material has a tensile breaking strength improved by 10% or more and a toughness improved by 15% or more compared to a silicone hydrogel not containing the additive polymer.

Images