Polymerizable composition for optical material, polymerizable prepolymer composition for optical material, cured product, and method for producing optical material

Abstract

The polymerizable composition for an optical material according to the present disclosure contains two or more different monomers for an optical material, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, at least one of the two or more different monomers for an optical material is an isocyanate compound, and the viscosity measured by a B-type viscometer at 25 DEG C and 60 rpm is 10-1000 mPas.

Description

Technical Field

[0001] The present disclosure relates to a polymerizable composition for an optical material, a polymerizable prepolymer composition for an optical material, a cured product, and a method for producing an optical material. Background Art

[0002] Examples of methods for producing a resin that can be used in an optical material for a plastic lens include a cast polymerization method in which a polymerizable composition containing a monomer is injected into a mold (casting mold) and then heated and cured.

[0003] In the casting polymerization method, after preparing a polymerizable composition and degassing it, the polymerizable composition is injected into a mold (casting mold), cured by heating (polymerization reaction), and the product is taken out of the mold (demolding) and annealed to obtain an optical material (for example, a lens, a semi-finished blank, etc.).

[0004] In the cast polymerization method, in order to improve the quality of the optical material, the polymerization reaction is usually carried out for a long time (for example, about 20 hours to 48 hours) while gradually raising the temperature of the polymerizable composition by heating. Therefore, it is known that a large proportion (for example, about 90%) of the total time required for the production of the optical material is spent on heating polymerization.

[0005] In the examples of Patent Document 1, it is described that the mold into which the polymerizable composition has been injected is gradually heated to 10° C. to 120° C., and polymerization is performed over 20 hours to obtain a molded body.

[0006] In addition, in the examples of Patent Document 2, it is described that the mold into which the polymerizable composition is injected is gradually heated from 25° C. to 120° C. over 16 hours, and heated at 120° C. for 4 hours to obtain a molded body.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2014 / 027427

[0010] Patent Document 2: International Publication No. 2014 / 133111 Summary of the invention

[0011] Problems to be solved by the invention

[0012] The polymerizable compositions used in the methods described in Patent Documents 1 and 2 have a high viscosity increase rate after preparation, and thus have room for improvement in pot life (usable time).

[0013] An object of one embodiment of the present disclosure is to provide a polymerizable composition and a polymerizable prepolymer composition that can shorten the production time of an optical material and have an excellent pot life.

[0014] Another problem to be solved by one embodiment of the present disclosure is to provide a method for producing an optical material using the polymerizable composition or polymerizable prepolymer composition and a cured product.

[0015] Means for solving problems

[0016] <1> A polymerizable composition for an optical material, comprising two or more different monomers for an optical material, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4,

[0017] At least one of the two or more different monomers for optical materials is an isocyanate compound,

[0018] The viscosity measured by a B-type viscometer at 25° C. and 60 rpm is 10 mPa·s to 1000 mPa·s.

[0019] <2> The polymerizable composition for an optical material according to <1>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring,

[0020] The content of the basic polymerization catalyst is 0.010 to 0.50 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0021] <3> The polymerizable composition for an optical material according to <1>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having no aromatic ring,

[0022] The content of the basic polymerization catalyst is greater than 0.05 parts by mass and less than 2.0 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0023] <4> The polymerizable composition for an optical material according to any one of <1> to <3>, further comprising a prepolymer which is a polymer of the two or more different monomers for an optical material and has a polymerizable functional group.

[0024] <5> A polymerizable composition for an optical material as described in any one of <1> to <4>, wherein the two or more different monomers for an optical material further contain at least one active hydrogen compound, and the active hydrogen compound is selected from the group consisting of a polythiol compound having two or more mercapto groups, a hydroxythiol compound containing one or more mercapto groups and one or more hydroxyl groups, a polyol compound containing two or more hydroxyl groups, and an amine compound.

[0025] <6> The polymerizable composition for an optical material as described in any one of <1> to <5>, wherein at least one of the two or more different monomers for an optical material is an active hydrogen compound, and the total proportion of the isocyanate compound and the active hydrogen compound in the total of the two or more different monomers for an optical material is greater than 70% by mass.

[0026] <7> The polymerizable composition for an optical material according to any one of <1> to <6>, wherein the number of moles of the functional groups of the organic acid having a pKa value of less than 4 is smaller than the number of moles of the functional groups of the basic polymerization catalyst.

[0027] <8> The polymerizable composition for an optical material according to any one of <1> to <7>, wherein the basic polymerization catalyst comprises a basic polymerization catalyst having a pKa value of 4 to 8.

[0028] <9> A polymerizable prepolymer composition for an optical material, comprising: a prepolymer which is a polymer of two or more different monomers for an optical material and has a polymerizable functional group; a basic polymerization catalyst; and an organic acid having a pKa value of less than 4,

[0029] At least one of the two or more different monomers for optical materials is an isocyanate compound,

[0030] The viscosity measured by a B-type viscometer at 25° C. and 60 rpm is 10 mPa·s to 2000 mPa·s.

[0031] <10> The polymerizable prepolymer composition for an optical material according to <9>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring,

[0032] The content of the basic polymerization catalyst is 0.002 to 1 part by mass based on 100 parts by mass of the total of the prepolymer.

[0033] <11> The polymerizable prepolymer composition for an optical material according to <9>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having no aromatic ring,

[0034] The content of the basic polymerization catalyst is 0.1 to 4.0 parts by mass based on 100 parts by mass of the total of the prepolymer.

[0035] <12> A cured product of the polymerizable composition for an optical material according to any one of <1> to <8> or the polymerizable prepolymer composition for an optical material according to any one of <9> to <11>.

[0036] <13> A method for producing an optical material, comprising:

[0037] a preparation step of preparing a polymerizable composition for an optical material, wherein the polymerizable composition for an optical material comprises two or more different monomers for an optical material, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4,

[0038] At least one of the two or more different monomers for optical materials is an isocyanate compound;

[0039] A casting step of adjusting the viscosity of the polymerizable composition for optical material to 10 mPa·s to 1000 mPa·s as measured by a B-type viscometer at 25° C. and 60 rpm, and casting the polymerizable composition for optical material into a mold; and

[0040] The curing step is to cure the polymerizable composition for optical material by polymerizing the two or more different monomers for optical material in the polymerizable composition for optical material in the mold.

[0041] <14> The method for producing an optical material according to <13>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring,

[0042] The content of the basic polymerization catalyst is 0.010 to 0.50 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0043] <15> The method for producing an optical material according to <13>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having no aromatic ring,

[0044] The content of the basic polymerization catalyst is greater than 0.05 parts by mass and less than 2.0 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0045] <16> A method for producing an optical material, comprising:

[0046] A preparation step of preparing two or more different monomers for optical materials and a basic polymerization catalyst;

[0047] a prepolymerization step of mixing a part of the two or more different monomers for optical materials with at least a part of the basic polymerization catalyst, polymerizing at least a part of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing the prepolymer; and

[0048] an acid adding step, adding an organic acid having a pKa value of less than 4 to the mixture containing the prepolymer;

[0049] At least one of the two or more different monomers for an optical material is an isocyanate compound.

[0050] <17> The method for producing an optical material according to <16>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring,

[0051] The total amount of the two or more different monomers for optical materials is 100 parts by mass, and the amount of the basic polymerization catalyst is 0.010 to 0.50 parts by mass.

[0052] <18> The method for producing an optical material according to <16>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having no aromatic ring,

[0053] The total amount of the two or more different monomers for optical materials is 100 parts by mass, and the amount of the basic polymerization catalyst is greater than 0.05 parts by mass and not more than 2.0 parts by mass.

[0054] <19> The method for producing an optical material according to any one of <16> to <19>, further comprising:

[0055] A step of producing a polymerizable composition for an optical material, comprising adding at least the remaining portion of the two or more different monomers for an optical material to a mixture containing the prepolymer, thereby obtaining a polymerizable composition for an optical material containing the two or more different monomers for an optical material, the prepolymer, the basic polymerization catalyst, and an organic acid having a pKa value of less than 4; and

[0056] The curing step is to obtain an optical material which is a cured product of the polymerizable composition for optical material by curing the two or more different monomers for optical material in the polymerizable composition for optical material.

[0057] <20> A cured product, which is a cured product of two or more different monomers for optical materials, at least one of the two or more different monomers for optical materials is an isocyanate compound, and there are no ribs with a length of 1.0 mm or more within a radius of 15 mm from the center of the cured product,

[0058] The content of amines measured by gas chromatography-mass spectrometry was more than 0 mass %, and the content of organic acids having a pKa value of less than 4 measured by gas chromatography-mass spectrometry was more than 0 mass %.

[0059] <21> The cured product according to <20>, wherein at least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring,

[0060] The content of the amine is 0.001 mass % to 0.50 mass %, and the content of the organic acid having a pKa value of less than 4 is 0.001 mass % to 1 mass %.

[0061] <22> The cured product according to <20>, wherein at least one of the two or more different monomers for an optical material is an isocyanate compound having no aromatic ring,

[0062] The content of the amine is 0.03 mass % to 2.5 mass %, and the content of the organic acid having a pKa value of less than 4 is 0.01 mass % to 5 mass %.

[0063] Effects of the Invention

[0064] According to one embodiment of the present disclosure, a polymerizable composition and a polymerizable prepolymer composition that can shorten the production time of an optical material and have an excellent pot life can be provided.

[0065] In addition, according to one embodiment of the present disclosure, a method for producing an optical material using the polymerizable composition or polymerizable prepolymer composition and a cured product thereof can be provided. DETAILED DESCRIPTION

[0066] In the present disclosure, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0067] In the present disclosure, when a plurality of substances belonging to each component are present in a composition, unless otherwise specified, the amount of each component in the composition means the total amount of the plurality of substances present in the composition.

[0068] In the numerical ranges recorded in stages in this disclosure, the upper limit or lower limit recorded in one numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in this disclosure, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiments.

[0069] In the present disclosure, the term "process" refers not only to an independent process but also to a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0070] 《Polymerizable composition for optical materials》

[0071] The polymerizable composition for optical materials of the present disclosure comprises two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, at least one of the two or more different monomers for optical materials is an isocyanate compound, and the viscosity thereof measured by a B-type viscometer at 25°C and 60 rpm is 10 mPa·s to 1000 mPa·s.

[0072] Hereinafter, the polymerizable composition for an optical material may also be simply referred to as a "polymerizable composition".

[0073] The polymerizable composition of the present disclosure can shorten the production time of optical materials and has an excellent pot life.

[0074] Specifically, by using a basic polymerization catalyst as a polymerization catalyst and making it more contained, the polymerization reaction during curing proceeds rapidly, and the production time of the optical material as a cured product is shortened. However, on the other hand, the viscosity of the polymerizable composition after preparation tends to increase, and the pot life tends to be short.

[0075] The polymerizable composition of the present disclosure suppresses viscosity increase after preparation by containing an organic acid having a pKa value of less than 4. This is considered to be because the organic acid having a pKa value of less than 4 forms a salt with a basic polymerization catalyst, thereby suppressing the activity of the basic polymerization catalyst.

[0076] It is considered that in the curing step of the polymerizable composition, the salt formed by the organic acid having a pKa value of less than 4 and the basic polymerization catalyst is dissociated by heat, the activity of the basic polymerization catalyst is exhibited, and the polymerization reaction proceeds rapidly.

[0077] Furthermore, since the polymerizable composition having an excellent pot life has excellent injectability into a mold, a cured product having excellent optical properties (less striae, etc.) can be obtained.

[0078] (Monomers for optical materials)

[0079] The polymerizable composition contains two or more different monomers for an optical material, and at least one of the monomers for an optical material is an isocyanate compound.

[0080] The monomer for optical material is not particularly limited as long as it is a monomer used in production of optical materials.

[0081] For example, it may be a monomer for producing an optical material having any of the following properties.

[0082] The total light transmittance of the optical material obtained by using the monomer for optical material may be 10% or more. The total light transmittance of the optical material may be measured in accordance with JIS K 7361-1 (1997).

[0083] The haze (i.e., total haze) of the optical material obtained using the monomer for optical material may be 10% or less, 1% or less, or 0.5% or less. The haze of the optical material is a value measured at 25°C using a haze meter [TC-HIIIDPK manufactured by Tokyo Denshoku Co., Ltd.] in accordance with JIS-K7105.

[0084] The refractive index of the optical material obtained using the optical material monomer is 1.56 or more, preferably 1.58 or more. The refractive index of the optical material obtained using the optical material monomer may be 1.80 or less, or 1.75 or less. The refractive index of the optical material may be measured in accordance with JIS K7142 (2014).

[0085] The shape of the optical material obtained using the monomer for an optical material is not particularly limited, and may be a plate shape, a columnar shape, a rectangular parallelepiped shape, or the like.

[0086] As monomers for optical materials, compounds having the property of being polymerized when using a basic polymerization catalyst described later can be cited. Specifically, isocyanate compounds, polythiol compounds having two or more thiol groups, hydroxythiol compounds containing one or more thiol groups and one or more hydroxyl groups, polyol compounds containing two or more hydroxyl groups, amine compounds, etc. can be cited.

[0087] The monomer for an optical material preferably contains an isocyanate compound and an active hydrogen compound.

[0088] The monomer for optical material preferably contains at least one active hydrogen compound selected from the group consisting of a polythiol compound having two or more mercapto groups, a hydroxythiol compound containing one or more mercapto groups and one or more hydroxyl groups, a polyol compound containing two or more hydroxyl groups, and an amine compound.

[0089] 〔Isocyanate compounds〕

[0090] As isocyanate compounds, aliphatic isocyanate compounds, alicyclic isocyanate compounds, aromatic isocyanate compounds, heterocyclic isocyanate compounds, etc. can be mentioned. These isocyanate compounds can include dimers, trimers, and prepolymers. As these isocyanate compounds, the compounds exemplified in International Publication No. 2011 / 055540 can be mentioned.

[0091] In addition, as the isocyanate compound, halogen-substituted compounds (e.g., chlorine-substituted compounds, bromine-substituted compounds, etc.), alkyl-substituted compounds, alkoxy-substituted compounds, carbodiimide-modified compounds, urea-modified compounds, or biuret-modified compounds of the above-mentioned compounds may also be used.

[0092] Prepolymer-type modified products of the above-mentioned compounds with nitro-substituted products, polyols, etc., dimerization or trimerization reaction products of the above-mentioned compounds, etc.

[0093] These compounds can be used alone or in combination of two or more.

[0094] In the present disclosure, an aliphatic isocyanate compound refers to an isocyanate compound that does not contain an aromatic structure, an alicyclic structure, or a heterocyclic structure.

[0095] The alicyclic isocyanate compound refers to an isocyanate compound which includes an alicyclic structure, does not include an aromatic structure, and may include a heterocyclic structure.

[0096] The aromatic isocyanate compound refers to an isocyanate compound which includes an aromatic structure and may include any one of an aliphatic structure, an alicyclic structure, and a heterocyclic structure, or a combination thereof.

[0097] The heterocyclic isocyanate compound refers to an isocyanate compound containing a heterocyclic structure and not containing an alicyclic structure or an aromatic structure.

[0098] In the present disclosure, a heterocyclic ring or heterocyclic structure having aromaticity does not belong to an aromatic ring or aromatic structure.

[0099] The two or more different monomers for an optical material preferably include at least one selected from the group consisting of an aliphatic isocyanate compound, an alicyclic isocyanate compound, an aromatic isocyanate compound, and a heterocyclic isocyanate compound.

[0100] At least one of the monomers for an optical material may be an isocyanate compound having an aromatic ring.

[0101] Examples of the aromatic ring include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring is preferred.

[0102] Specific examples of the isocyanate compound having an aromatic ring include aromatic isocyanate compounds, and more specific examples include isocyanate compounds in which an isocyanate group is directly bonded to an aromatic ring and isocyanate compounds in which an isocyanate group is bonded to a benzyl position of an aromatic ring.

[0103] An isocyanate compound having an aromatic ring is preferred from the viewpoint that the isocyanate group of the isocyanate compound having an aromatic ring is highly active and the polymerization reaction is easily promoted compared to an isocyanate compound not having an aromatic ring.

[0104] At least one of the monomers for an optical material may be an isocyanate compound having no aromatic ring.

[0105] Specific examples of the isocyanate compound having no aromatic ring include alicyclic isocyanate compounds, heterocyclic isocyanate compounds, and aliphatic isocyanate compounds having no aromatic ring.

[0106] Compared with an isocyanate compound having an aromatic ring, an isocyanate compound not having an aromatic ring is preferred in that the polymerization reaction rate is not too high and the polymerization reaction is easily controlled.

[0107] The monomer for an optical material may contain an isocyanate compound having an aromatic ring and an isocyanate compound not having an aromatic ring.

[0108] When the monomer for optical materials contains an isocyanate compound without an aromatic ring and an isocyanate compound with an aromatic ring, from the viewpoint of controlling the polymerization reaction, the ratio (A:B) of the isocyanate compound without an aromatic ring to the isocyanate compound with an aromatic ring is preferably in the range of 3:7 to 0:10, more preferably in the range of 2:8 to 0:10, in terms of the molar ratio of the isocyanate group.

[0109] When the monomer for optical material contains an isocyanate compound having no aromatic ring and an isocyanate compound having an aromatic ring, the number of moles of isocyanate groups in the isocyanate compound having no aromatic ring is preferably smaller than the number of moles of isocyanate groups in the isocyanate compound having an aromatic ring.

[0110] From the viewpoint of maintaining the quality of the optical material and shortening the production time of the optical material, the isocyanate compound preferably includes at least one selected from isophorone diisocyanate, 2,5-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, m-xylylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, dicyclohexylmethane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, 1,6-hexamethylene diisocyanate, and 1,5-pentamethylene diisocyanate.

[0111] More preferably, it contains at least one selected from isophorone diisocyanate, 2,5-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane, m-xylylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatemethyl)cyclohexane.

[0112] 〔Active hydrogen compounds〕

[0113] Examples of the active hydrogen compound include polythiol compounds having two or more mercapto groups, hydroxythiol compounds containing one or more mercapto groups and one or more hydroxyl groups, polyol compounds containing two or more hydroxyl groups, and amine compounds.

[0114] As the active hydrogen compound, oligomers of the above-mentioned active hydrogen compounds and halogen-substituted products (for example, chlorine-substituted products, bromine-substituted products, etc.) of the above-mentioned active hydrogen compounds can be used.

[0115] The active hydrogen compound may be used alone or in combination of two or more.

[0116] (Polythiol compound having two or more mercapto groups)

[0117] Examples of the polythiol compound having two or more mercapto groups include compounds exemplified in International Publication No. 2016 / 125736.

[0118] From the viewpoint of maintaining the quality of the optical material and shortening the production time of the optical material, the polythiol compound preferably includes 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, at least one of 9-trithiaundecane, pentaerythritol tetrakis(3-mercaptopropionate), bis(mercaptoethyl) sulfide, pentaerythritol tetrakis(2-mercaptoacetate), 2,5-bis(mercaptomethyl)-1,4-dithiacyclohexane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiacyclohexane, and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiacyclohexane,

[0119] More preferably, it contains at least one selected from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), and 2,5-bis(mercaptomethyl)-1,4-dithiacyclohexane.

[0120] More preferably, the compound contains at least one selected from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and pentaerythritol tetrakis(3-mercaptopropionate).

[0121] (Polythiol compound having three or more mercapto groups)

[0122] Examples of the active hydrogen compound include polythiol compounds having three or more mercapto groups.

[0123] In the case where the polymerizable composition contains a polythiol compound having three or more mercapto groups as the active hydrogen compound, from the viewpoint of promoting the polymerization reaction, it is preferred to contain a compound in which at least one of the three or more mercapto groups contained in the aforementioned polythiol compound having three or more mercapto groups is replaced by a group represented by the following formula (N1) (also referred to as compound (N1)).

[0124] [Chemical formula 1]

[0125]

[0126] In formula (N1), * represents a bonding position.

[0127] When the polymerizable composition contains a polythiol compound having three or more mercapto groups as the active hydrogen compound, from the viewpoint of facilitating the regulation of the polymerization reaction, the peak area of ​​the compound (N1) is preferably 3.0 or less, more preferably 1.5 or less, relative to the peak area of ​​100 of the polythiol compound having three or more mercapto groups, when the peak area is measured by high performance liquid chromatography.

[0128] When the peak area is measured by high performance liquid chromatography, the peak area of ​​the compound (N1) is preferably 0.01 or more relative to 100 of the peak area of ​​the polythiol compound having three or more mercapto groups from the viewpoint of promoting the polymerization reaction.

[0129] The peak area by high performance liquid chromatography can be measured by the method described in paragraph 0146 of International Publication No. 2014 / 027665 and the like.

[0130] (Hydroxythiol compounds containing one or more mercapto groups and one or more hydroxyl groups)

[0131] Examples of the thiol compound having a hydroxyl group include 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerol bis(thioglycolate), 4-mercaptophenol, 2,3-dimercapto-1-propanol, pentaerythritol tris(3-mercaptopropionate), and pentaerythritol tris(thioglycolate).

[0132] (Polyol compound containing two or more hydroxyl groups)

[0133] As the polyol compound, one or more aliphatic or alicyclic alcohols can be mentioned. Specifically, linear or branched aliphatic alcohols, alicyclic alcohols, alcohols obtained by adding at least one selected from the group consisting of ethylene oxide, propylene oxide and ε-caprolactone to these alcohols, etc. can be mentioned. More specifically, the compounds exemplified in International Publication No. 2016 / 125736 can be mentioned.

[0134] The polyol compound is preferably at least one selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, and 1,4-cyclohexanediol.

[0135] (Amine compound)

[0136] Examples of the amine compound include ethylenediamine, 1,2- or 1,3-diaminopropane, 1,2-, 1,3- or 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,10-diaminodecane, 1,2-, 1,3- or 1,4-diaminocyclohexane, o-, m- or p-diaminobenzene, 3,4- or 4,4'-diaminobenzophenone, 3,4- or 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diamino Primary polyamine compounds such as 1,3- or 1,4-diaminomethylcyclohexane, 2- or 4-aminopiperidine, 2- or 4-aminomethylpiperidine, 2- or 4-aminoethylpiperidine, 2- or 4-aminoethylpiperidine, 1,5-, 1,8- or 2,3-diaminonaphthalene, 2,3-, 2,6- or 3,4-diaminopyridine, 2,4- or 2,6-diaminotoluene, m- or p-phenylenediamine, isophoronediamine, diaminomethyldicycloheptane, 1,3- or 1,4-diaminomethylcyclohexane, 2- or 4-aminopiperidine, 2- or 4-aminomethylpiperidine, 2- or 4-aminoethylpiperidine, N-aminoethylmorpholine, and N-aminopropylmorpholine;

[0137] Monofunctional secondary amine compounds such as diethylamine, dipropylamine, di-n-butylamine, di-sec-butylamine, diisobutylamine, di-n-pentylamine, di-3-pentylamine, dihexylamine, dioctylamine, di(2-ethylhexyl)amine, methylhexylamine, diallylamine, N-methylallylamine, piperidine, pyrrolidine, diphenylamine, N-methylamine, N-ethylamine, dibenzylamine, N-methylbenzylamine, N-ethylbenzylamine, dicyclohexylamine, N-methylaniline, N-ethylaniline, dinaphthylamine, 1-methylpiperazine, and morpholine;

[0138] N,N'-dimethylethylenediamine, N,N'-dimethyl-1,2-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N,N'-dimethyl-1,2-diaminobutane, N,N'-dimethyl-1,3-diaminobutane, N,N'-dimethyl-1,4-diaminobutane, N,N'-dimethyl-1,5-diaminopentane, N,N'-dimethyl-1,6-diaminohexane, N,N'-dimethyl-1,7-diaminoheptane, N,N'-diethylethylenediamine, N,N'-diethyl-1,2-diaminopropane, N,N'-diethyl-1,3-diaminopropane, N,N' -diethyl-1,2-diaminobutane, N,N'-diethyl-1,3-diaminobutane, N,N'-diethyl-1,4-diaminobutane, N,N'-diethyl-1,5-diaminopentane, N,N'-diethyl-1,6-diaminohexane, N,N'-diethyl-1,7-diaminoheptane, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, homopiperazine, 1,1-di(4-piperidinyl)methane, 1,2-di(4-piperidinyl)ethane, 1,3-di(4-piperidinyl)propane, 1,4-di(4-piperidinyl)butane, tetramethylguanidine and other secondary polyamine compounds; etc.

[0139] Among the above, from the viewpoint of improving the heat resistance and refractive index of the cured product, the active hydrogen compound preferably includes a polythiol compound having two or more mercapto groups.

[0140] The content of the polythiol compound having two or more mercapto groups is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the active hydrogen compound.

[0141] As the active hydrogen compound, the total content of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and pentaerythritol tetrakis(3-mercaptopropionate) is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the active hydrogen compound.

[0142] In the polymerizable composition, the molar ratio of the total of the hydroxyl group (OH group) and the mercapto group (SH group) in the active hydrogen compound to the isocyanate group (NCO group) in the isocyanate compound (NCO group / (OH group+SH group)) is preferably 0.8 or more, more preferably 0.85 or more, and even more preferably 0.9 or more.

[0143] In the polymerizable composition, the molar ratio of the total of the hydroxyl group (OH group) and the mercapto group (SH group) in the active hydrogen compound to the isocyanate group (NCO group) in the isocyanate compound (NCO group / (OH group+SH group)) is preferably 1.2 or less, more preferably 1.15 or less, and further preferably 1.1 or less.

[0144] When the polymerizable composition contains an isocyanate compound and an active hydrogen compound as monomers for an optical material, the total proportion of the isocyanate compound and the active hydrogen compound in the entire monomers for an optical material is preferably greater than 70% by mass, more preferably 75% by mass or more, and even more preferably 80% by mass or more.

[0145] The total proportion of the isocyanate compound and the active hydrogen compound in the entire monomer for an optical material may be 100% by mass, less than 100% by mass, 95% by mass or less, or 90% by mass or less.

[0146] <Basic polymerization catalyst>

[0147] The polymerizable composition comprises at least one basic polymerization catalyst.

[0148] The basic polymerization catalyst may be used alone or in combination of two or more.

[0149] Examples of the basic polymerization catalyst include amine catalysts (including imidazole catalysts) and the like.

[0150] Specific examples of the amine catalyst include triethylenediamine, N,N-dimethylethanolamine, triethylamine, N-ethylmorpholine, 2-methylpyrazine, pyridine, α-methylpyridine, β-methylpyridine, γ-methylpyridine, 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2-propylpyridine, 2,4-lutidine, 3,4-lutidine, 2-methyl-5-ethylpyridine, 3,5-diethylpyridine, 2,3,5-trimethylpyridine, 2,3-cyclopentapyridine, 2,3-cyclohexapyridine, 2 ,3-cycloheptenpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-(4-methylphenyl)pyridine, 2,6-lutidine, 3,5-lutidine, 2,4,6-trimethylpyridine, 3-chloropyridine, N,N-diethylaniline, N,N-dimethylaniline, hexamethylenetetramine, quinoline, isoquinoline, N,N-dimethyl-p-toluidine, N,N-dimethylpiperazine, quinaldine, 4-methylmorpholine, triallylamine, trioctylamine, 1-phenylimidazole, 1.2-dimethylimidazole, 1-benzyl-2-methylimidazole, etc.

[0151] As the basic polymerization catalyst, an amine catalyst is preferred.

[0152] Preferred amine catalysts include tertiary amine catalysts such as 3,5-lutidine, 2,6-lutidine, 2,4,6-collidine, 2-ethylpyridine, 2,4-lutidine, 2-methyl-5-ethylpyridine, 2,3,5-collidine, triethylenediamine, N,N-dimethylethanolamine, triethylamine, and N-ethylmorpholine.

[0153] From the viewpoint of promoting the polymerization reaction during the curing step, the amine catalyst preferably includes at least one selected from 3,5-lutidine, 2,6-lutidine, 2,4,6-collidine, 2-ethylpyridine, 2,4-lutidine, 2-methyl-5-ethylpyridine, 2,3,5-collidine, triethylenediamine, and N-ethylmorpholine.

[0154] The basic polymerization catalyst also preferably contains a compound represented by the following general formula (2) and / or a compound represented by the following general formula (3).

[0155] [Chemical formula 2]

[0156]

[0157] In the general formula (2), R1 represents a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a halogen atom, and multiple R1s may be the same or different. Q represents a carbon atom or a nitrogen atom. m represents an integer of 0 to 5.

[0158] [Chemical formula 3]

[0159]

[0160] In the general formula (3), R2, R3 and R4 each independently represent a linear alkyl group having 3 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an allyl group, or a hydrocarbon group containing a hydroxyl group.

[0161] The pKa value of the basic polymerization catalyst is preferably 1 or more, more preferably 3 or more, and further preferably 4 or more.

[0162] The pKa value of the basic polymerization catalyst is preferably 9 or less, more preferably 8 or less.

[0163] The pKa value (acid dissociation index) can be measured, for example, by (a) the method described in The Journal of Physical Chemistry vol. 68, number 6, page 1560 (1964), (b) a method using a potentiometric automatic titrator (AT-610 (trade name) etc. manufactured by Kyoto Electronics Co., Ltd.), etc. Alternatively, the acid dissociation index described in (c) the Chemical Handbook of Japan (revised 3rd edition, June 25, 1974, issued by Maruzen Co., Ltd.) can be used as the pKa value of the basic polymerization catalyst.

[0164] The basic polymerization catalyst preferably contains at least one selected from basic polymerization catalysts having a pKa value of 4 to 8.

[0165] In the polymerizable composition of the present disclosure, the content of the basic polymerization catalyst relative to 100 parts by mass of the total of two or more different monomers for an optical material is not particularly limited.

[0166] For example, the content of the basic polymerization catalyst can be selected from the range of 0.010 parts by mass to 2.0 parts by mass based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0167] The polymerizable composition having the basic polymerization catalyst content within the above range contains a larger amount of the polymerization catalyst than the polymerizable composition used in the conventional method for producing an optical material.

[0168] Thus, when the monomers for optical materials in the polymerizable composition are polymerized in the curing step, the reaction heat of the polymerizable composition (ie, heat generated by self-heating) can be generated in a short time. As a result, the polymerization reaction can be favorably promoted.

[0169] In addition, the viscosity of the polymerizable composition increases rapidly due to the polymerization reaction, so that the heat convection that is presumed to be the cause of striae is suppressed. As a result, a high-quality optical material can be obtained.

[0170] The content of the basic polymerization catalyst can be determined according to the type of the isocyanate compound contained in the polymerizable composition. For example, the content of the basic polymerization catalyst can be determined according to the presence or absence of an aromatic ring in the isocyanate compound.

[0171] When at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring, the content of the basic polymerization catalyst is preferably 0.010 to 0.50 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0172] By making the content of the basic polymerization catalyst used together with the isocyanate compound having an aromatic ring be more than 0.010 parts by mass, the polymerization reaction can be well promoted, and a high-quality optical material can be obtained in a short time. In addition, by well promoting the polymerization reaction, the demoulding property when the cured product is taken out from the mold can be improved.

[0173] From the above viewpoints, the content of the basic polymerization catalyst is preferably 0.020 parts by mass or more, and more preferably 0.030 parts by mass or more, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0174] By setting the content of the basic polymerization catalyst used together with the isocyanate compound having an aromatic ring to 0.50 parts by mass or less, for example, the workability when the polymerizable composition is injected into a mold can be improved.

[0175] From the above viewpoints, the content of the basic polymerization catalyst is preferably 0.20 parts by mass or less, more preferably 0.10 parts by mass or less, and even more preferably 0.09 parts by mass or less, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0176] When at least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, the content of the basic polymerization catalyst is preferably greater than 0.05 parts by mass and less than 2.0 parts by mass based on 100 parts by mass of the total of the two or more different monomers for optical materials.

[0177] By making the content of the basic polymerization catalyst used together with the isocyanate compound without aromatic ring greater than 0.05 parts by mass, the polymerization reaction can be well promoted, so that high-quality optical materials can be obtained in a short time. In addition, by well promoting the polymerization reaction, the demoulding property when the cured product is taken out from the mold can be improved.

[0178] From the above viewpoints, the content of the basic polymerization catalyst is preferably 0.08 parts by mass or more, preferably 0.10 parts by mass or more, more preferably 0.13 parts by mass or more, and further preferably 0.15 parts by mass or more based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0179] By setting the content of the basic polymerization catalyst used together with the isocyanate compound having no aromatic ring to 2.0 parts by mass or less, for example, the workability when the polymerizable composition is injected into a mold can be improved.

[0180] From the above viewpoints, the content of the basic polymerization catalyst relative to a total of 100 parts by mass of two or more different monomers for optical materials is preferably 1.8 parts by mass or less, more preferably 1.5 parts by mass or less, further preferably 1.0 part by mass or less, particularly preferably 0.5 parts by mass or less, and further preferably 0.3 parts by mass or less.

[0181] In the present disclosure, the content of the basic polymerization catalyst in the polymerizable composition can be appropriately set by the type of the basic polymerization catalyst, the type and amount of monomers used (isocyanate compound, active hydrogen compound, other components, etc.), and the shape of the desired molded product.

[0182] When the polymerizable composition contains a prepolymer which is a polymer of a monomer for an optical material, the content of the basic polymerization catalyst is a content based on 100 parts by mass of the monomer for an optical material which is a raw material including the prepolymer.

[0183] The above-mentioned range of the content of the basic polymerization catalyst can be appropriately changed according to the types of the monomer for optical material and the polymerization catalyst.

[0184] The basic polymerization catalyst preferably satisfies the following condition 1.

[0185] [Condition 1]

[0186] -Ea / R is above -7100 and below -2900.

[0187] (Ea is the activation energy calculated from the reaction rate constants of the two or more different monomers for optical materials at two or more different temperatures using an Arrhenius plot, and R is the gas constant (8.314 J / mol / K).)

[0188] By making the basic polymerization catalyst satisfy condition 1, it is possible to suppress the variation in the polymerization rate of the polymerizable composition. As a result, the generation of optical strain and striae is suppressed, and an optical material having excellent appearance can be obtained.

[0189] The value of Ea is calculated by the following method.

[0190] The value of Ea is calculated by performing the following steps:

[0191] A physical property acquisition step of heating a composition 1 comprising a polymerizable compound and a predetermined amount of a polymerization catalyst, and acquiring physical property values ​​1a derived from functional groups of the polymerizable compound before heating and physical property values ​​1b derived from residual functional groups after heating for a predetermined time when the composition is kept at various temperatures;

[0192] A residual functional group rate calculation step, calculating the residual functional group rate 1 at the above-mentioned various temperatures from the physical property value 1a and the physical property value 1b;

[0193] a reaction rate constant calculation step of calculating the reaction rate constant 1 at the above-mentioned plurality of temperatures from the residual functional group ratio 1 based on the reaction rate formula; and

[0194] In the fitting step, activation energy Ea1 and frequency factor A1 are calculated from the reaction rate constant 1 at various temperatures through the Arrhenius curve diagram.

[0195] Using the calculated Ea, it is determined whether the polymerization catalyst satisfies condition 1.

[0196] The specific method for calculating the Ea value and the method for determining whether the polymerization catalyst satisfies Condition 1 are the same as those described in International Publication No. 2020 / 256057.

[0197] <Organic acids with pKa values ​​less than 4>

[0198] The polymerizable composition of the present disclosure comprises at least one organic acid having a pKa value of less than 4.

[0199] The organic acid having a pKa value of less than 4 may be used alone or in combination of two or more.

[0200] The organic acid having a pKa value of less than 4 contained in the polymerizable composition forms a salt with the basic polymerization catalyst to suppress the activity of the basic polymerization catalyst. Therefore, the viscosity increase accompanying the polymerization reaction of the monomer after the preparation of the polymerizable composition is suppressed, and the pot life is improved.

[0201] Specific examples of organic acids having a pKa value of less than 4 include 10-camphorsulfonic acid (pKa: 1.2), methanesulfonic acid (pKa: -2.6), ethanesulfonic acid (pKa: 1.8), propanesulfonic acid (pKa: 1.9), butanesulfonic acid (pKa: 1.9), p-toluenesulfonic acid (pKa: -2.8), vinylsulfonic acid (pKa: -2.7), benzenesulfonic acid (pKa: 0.7), formic acid (pKa: 3.8), and phthalic acid (pKa: 2.9).

[0202] Organic acids can form hydrates.

[0203] The content of the organic acid having a pKa value of less than 4 contained in the polymerizable composition may be, for example, 0.001 parts by mass or more relative to 100 parts by mass of the total of the two or more different monomers for an optical material.

[0204] When the content of the organic acid having a pKa value of less than 4 is 0.001 parts by mass or more based on 100 parts by mass of the total of two or more different monomers for an optical material, an increase in the viscosity of the polymerizable composition is effectively suppressed.

[0205] From the above viewpoints, the content of the organic acid having a pKa value of less than 4 is preferably 0.005 parts by mass or more, and more preferably 0.01 parts by mass or more, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0206] For example, the content of the organic acid having a pKa value of less than 4 contained in the polymerizable composition may be 1 part by mass or less relative to 100 parts by mass of the total of two or more different monomers for an optical material.

[0207] When the content of the organic acid having a pKa value of less than 4 is 1 part by mass or less relative to 100 parts by mass of the total of two or more different monomers for optical materials, the thermal dissociation of the salt formed by the organic acid and the basic polymerization catalyst is promoted in the curing step, and the activity of the basic polymerization catalyst is easily exhibited. Thus, the polymerization reaction can be rapidly carried out.

[0208] From the above viewpoints, the content of the organic acid having a pKa value of less than 4 is preferably 0.50 parts by mass or less, and more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0209] When the polymerizable composition contains a prepolymer which is a polymer of a monomer for an optical material, the content of the organic acid having a pKa value of less than 4 is a content relative to 100 parts by mass of the monomer for an optical material which is a raw material including the prepolymer.

[0210] The molar ratio (X / Y) of the organic acid (X) having a pKa value of less than 4 to the basic polymerization catalyst (Y) is preferably 0.1 to 2.0, more preferably 0.15 to 1.25, and even more preferably 0.2 to 1.2.

[0211] From the viewpoint of well expressing the activity of the basic polymerization catalyst, the number of moles (x) of the functional group of the organic acid having a pKa value of less than 4 in the polymerizable composition is preferably less than the number of moles (y) of the functional group of the basic polymerization catalyst (the molar ratio represented by x / y is less than 1.0). That is, it is preferred that an excess amount of the basic polymerization catalyst relative to the organic acid having a pKa value of less than 4 is present in the polymerizable composition.

[0212] (Other additives)

[0213] The polymerizable composition may contain any additives.

[0214] As the optional additives, there can be mentioned a photochromic compound, an internal mold release agent, a bluing agent, an ultraviolet absorber, and the like.

[0215] (Photochromic Compounds)

[0216] A photochromic compound is a compound whose molecular structure changes reversibly when irradiated with light of a specific wavelength, and whose light absorption characteristics (absorption spectrum) change accordingly.

[0217] Examples of the photochromic compound include compounds whose light absorption characteristics (absorption spectrum) change with respect to light of a specific wavelength.

[0218] The photochromic compound is not particularly limited, and any photochromic compound can be appropriately selected from the compounds known in the art that can be used for photochromic lenses. For example, one or more of spiropyran compounds, spirooxazine compounds, fulgide compounds, naphthopyran compounds, bisimidazole compounds, etc. can be used according to the desired coloring.

[0219] (Internal release agent)

[0220] Examples of the internal mold release agent include acidic phosphate esters. Examples of the acidic phosphate esters include phosphoric acid monoesters and phosphoric acid diesters, and these may be used alone or in combination of two or more.

[0221] (Bluing agent)

[0222] Examples of the bluing agent include substances that have an absorption band in the orange to yellow wavelength region in the visible light region and have a function of adjusting the hue of an optical material formed of a resin. More specifically, the bluing agent includes substances that exhibit blue to purple.

[0223] (Ultraviolet light absorber)

[0224] Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers such as 2,2′-dihydroxy-4-methoxybenzophenone, triazine ultraviolet absorbers such as 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and benzotriazole ultraviolet absorbers such as 2-(2H-benzotriazol-2-yl)-4-methylphenol, 2-(2H-benzotriazol-2-yl)-4-tert-octylphenol, and 2-(5-chloro-2H-benzotriazol-2-yl)-4-methyl-6-tert-butylphenol.

[0225] (Viscosity)

[0226] From the viewpoint of suppressing striae in the cured product, the polymerizable composition has a viscosity measured at 25°C and 60 rpm using a B-type viscometer of 10 mPa·s or more, preferably 40 mPa·s or more, more preferably 70 mPa·s or more, further preferably 80 mPa·s or more, particularly preferably 100 mPa·s or more, and even more preferably 120 mPa·s or more.

[0227] The polymerizable composition has a viscosity of 1000 mPa·s or less, preferably 700 mPa·s or less, and more preferably 400 mPa·s or less, as measured by a B-type viscometer at 25° C. and 60 rpm, in order to maintain good workability when molding the optical material into a desired shape.

[0228] The viscosity of the polymerizable composition can be adjusted according to the application of the obtained cured product.

[0229] For example, when a cured product is obtained using a mold for a convex lens, the end surface (i.e., the injection port) is narrow (e.g., 1 mm to 3 mm), so from the viewpoint of suppressing striae, the viscosity of the polymerizable composition is preferably 10 mPa·s to 100 mPa·s.

[0230] On the other hand, when a cured product is obtained using a conventional lens mold other than a convex lens, the end face (i.e., the injection port) is wide (e.g., 5 mm to 15 mm), so from the viewpoint of suppressing ribs, the viscosity of the polymerizable composition is preferably 10 mPa·s to 1000 mPa·s, and more preferably 100 mPa·s to 1000 mPa·s.

[0231] By increasing the viscosity of the polymerizable composition, when heat is applied from the outside, heat convection caused by the temperature difference between the inside and the outside of the polymerizable composition can be suppressed, and striae caused by heat convection can be reduced.

[0232] If the amount of catalyst is small as in conventional polymerizable compositions, the viscosity increase rate during polymerization is insufficient, so the viscosity does not increase to a level that can suppress heat convection, and the temperature cannot be raised rapidly in a short time. In addition, the time required to complete the polymerization also becomes longer.

[0233] On the other hand, by taking into account the reactivity of the isocyanate compound having an aromatic ring as described in the present disclosure, the amount of catalyst is increased to an optimal range, thereby enabling the viscosity of the composition as a whole to be increased more quickly. Thus, while suppressing uneven polymerization, thermal convection caused by a rapid temperature rise can be suppressed, and polymerization can be performed in a short time.

[0234] (Viscosity increase speed)

[0235] From the viewpoint of shortening the curing time of the polymerizable composition, the slope of the viscosity increase rate of the polymerizable composition is preferably 0.005 or more, more preferably 0.007 or more, and even more preferably 0.01 or more.

[0236] From the viewpoint of increasing the pot life of the polymerizable composition, the slope of the viscosity increase rate is preferably 0.04 or less, more preferably 0.035 or less, and even more preferably 0.03 or less.

[0237] The slope of the viscosity increase rate of the polymerizable composition is the value of b when fitting is performed using the following formula by plotting the change in viscosity over time at 25° C. with the horizontal axis (=X) being time (hr) and the vertical axis (=Y) being the viscosity (mPa·S) of the polymerizable composition. In the formula, a is the intercept.

[0238] Y=a*exp(b*X)

[0239] The viscosity X of the polymerizable composition in the above formula is measured using a Brookfield viscometer at 25° C. and 60 rpm or 30 rpm.

[0240] The time Y in the above formula is defined as the time elapsed from a reference time (for example, the time of preparation of the polymerizable composition).

[0241] (Thixotropic ratio)

[0242] The thixotropic ratio of the polymerizable composition is preferably 1.3 or less, more preferably 1.2 or less, and even more preferably 1.1 or less.

[0243] When the thixotropic ratio of the polymerizable composition is 1.3 or less, the composition can be quickly filled into a polymerization container such as a mold, and heat convection during polymerization can be suppressed to effectively prevent the generation of striae, etc. As a result, the quality of the obtained optical material can be well maintained.

[0244] The thixotropic ratio of the polymerizable composition is preferably 0.9 or more, more preferably 0.95 or more, and even more preferably 1.0 or more.

[0245] The thixotropic ratio of the polymerizable composition is calculated by dividing the viscosity η1 measured by a Brookfield viscometer at 25° C. and a rotation speed of 6 rpm by the viscosity η2 measured at a rotation speed of 60 rpm.

[0246] The thixotropic ratio of the polymerizable composition can be reduced, for example, by reducing the molecular weights of two or more monomers for optical materials, suppressing the degree of polymerization of the prepolymer to a certain value or less, or reducing the ratio of the structure providing elasticity in the monomer.

[0247] The polymerizable composition preferably further contains a prepolymer which is a polymer of two or more different monomers for an optical material and has a polymerizable functional group.

[0248] In the present disclosure, the prepolymer refers to a polymer which is a polymer of two or more different monomers for optical materials and has a polymerizable functional group.

[0249] A cured product obtained by polymerizing a prepolymer and two or more different monomers for an optical material can be used as an optical material.

[0250] Examples of the prepolymer include a polymer obtained by not polymerizing two optical material monomers in an equivalent ratio of 1:1 and a polymer obtained by polymerizing two optical material monomers in an unbalanced equivalent ratio.

[0251] In the present disclosure, a polymerizable functional group refers to a functional group that can polymerize with other polymerizable functional groups. Specific examples of the polymerizable functional group include functional groups having active hydrogen such as an isocyanate group and a mercapto group described later.

[0252] In the present disclosure, polymerization at an equivalent ratio of 1:1 means, for example, polymerization using an isocyanate compound and a polythiol compound, polymerization is performed in an amount where the isocyanate group of the isocyanate compound and the mercapto group of the polythiol compound have a molar ratio of 1:1.

[0253] 《Polymerizable prepolymer composition for optical materials》

[0254] The polymerizable prepolymer composition for optical material of the present disclosure comprises: a prepolymer which is a polymer of two or more different monomers for optical material and has a polymerizable functional group; a basic polymerization catalyst; and an organic acid having a pKa value of less than 4.

[0255] At least one of the two or more different monomers for an optical material is an isocyanate compound, and has a viscosity of 10 to 2000 mPa·s as measured by a Brookfield viscometer at 25° C. and 60 rpm.

[0256] Hereinafter, the polymerizable prepolymer composition for an optical material may also be simply referred to as a "polymerizable prepolymer composition".

[0257] The polymerizable prepolymer composition of the present disclosure can shorten the production time of optical materials and has an excellent pot life.

[0258] The specific examples, preferred specific examples, preferred modes, etc. of the monomer for optical material, the basic polymerization catalyst and the organic acid having a pKa value of less than 4 of the polymerizable prepolymer composition are the same as the specific examples, preferred specific examples, preferred modes, etc. of the monomer for optical material, the basic polymerization catalyst and the organic acid having a pKa value of less than 4 described in the above-mentioned polymerizable composition for optical material.

[0259] The definition of the prepolymer of the polymerizable prepolymer composition is the same as the definition of the prepolymer described in the above-mentioned section of the polymerizable composition.

[0260] Specific examples, preferred specific examples, preferred aspects, etc. of the physical properties of the polymerizable prepolymer composition, such as viscosity, are the same as the specific examples, preferred specific examples, preferred aspects, etc. of the physical properties described in the section of the polymerizable composition for an optical material.

[0261] In the polymerizable prepolymer composition of the present disclosure, the content of the basic polymerization catalyst relative to 100 parts by mass of the total of two or more different monomers for optical materials is not particularly limited.

[0262] For example, the content of the basic polymerization catalyst can be selected from the range of 0.002 parts by mass to 4.0 parts by mass based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0263] The content of the basic polymerization catalyst can be determined according to the type of the isocyanate compound contained in the polymerizable prepolymer composition. For example, the content of the basic polymerization catalyst can be determined according to the presence or absence of an aromatic ring in the isocyanate compound.

[0264] When at least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, the content of the basic polymerization catalyst contained in the polymerizable prepolymer composition is preferably 0.002 to 1 parts by mass based on 100 parts by mass of the total of the two or more different monomers for optical materials.

[0265] By making the content of the basic polymerization catalyst used together with the isocyanate compound with an aromatic ring be more than 0.002 parts by mass, the polymerization reaction can be promoted well, so a high-quality optical material can be obtained in a short time. In addition, by promoting the polymerization reaction well, the demoulding property when the cured product is taken out from the mold can be improved.

[0266] From the above viewpoints, the content of the basic polymerization catalyst is preferably 0.010 parts by mass or more, more preferably 0.050 parts by mass or more, and even more preferably 0.070 parts by mass or more, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0267] By setting the content of the basic polymerization catalyst used together with the isocyanate compound having an aromatic ring to 1 part by mass or less, for example, the workability when injecting the polymerizable prepolymer composition into a mold can be improved.

[0268] From the above viewpoints, the content of the basic polymerization catalyst is preferably 0.50 parts by mass or less, more preferably 0.15 parts by mass or less, and even more preferably 0.10 parts by mass or less, based on 100 parts by mass of the total of the two or more different monomers for an optical material.

[0269] When at least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, the content of the basic polymerization catalyst contained in the polymerizable prepolymer composition is preferably 0.1 to 4.0 parts by mass relative to 100 parts by mass of the total of the two or more different monomers for optical materials.

[0270] By making the content of the basic polymerization catalyst used together with the isocyanate compound without aromatic ring to be more than 0.1 parts by mass, the polymerization reaction can be well promoted, so that high-quality optical materials can be obtained in a short time. In addition, by well promoting the polymerization reaction, the demoulding property when the cured product is taken out from the mold can be improved.

[0271] From the above viewpoints, the content of the polymerization catalyst is preferably 0.15 parts by mass or more, and more preferably 0.20 parts by mass or more, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0272] By setting the content of the basic polymerization catalyst used together with the isocyanate compound having no aromatic ring to 4.0 parts by mass or less, for example, the workability when injecting the polymerizable prepolymer composition into a mold can be improved.

[0273] From the above viewpoints, the content of the basic polymerization catalyst is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and even more preferably 1.0 parts by mass or less, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0274] (Viscosity)

[0275] With regard to the polymerizable prepolymer composition, from the viewpoint of suppressing striae in the cured product, the viscosity measured by a B-type viscometer at 25°C and 60 rpm is 10 mPa·s or more, preferably 40 mPa·s or more, more preferably 70 mPa·s or more, further preferably 80 mPa·s or more, particularly preferably 100 mPa·s or more, and even more preferably 120 mPa·s or more.

[0276] The method for measuring the viscosity of the polymerizable prepolymer composition is as described above.

[0277] (Viscosity increase speed)

[0278] From the viewpoint of shortening the curing time of the polymerizable prepolymer composition, the slope of the viscosity increase rate of the polymerizable prepolymer composition is preferably 0.005 or more, more preferably 0.007 or more, and even more preferably 0.01 or more.

[0279] From the viewpoint of increasing the pot life of the polymerizable prepolymer composition, the slope of the viscosity increase rate is preferably 0.04 or less, more preferably 0.035 or less, and even more preferably 0.03 or less.

[0280] The method for measuring the slope of the viscosity increase rate of the polymerizable prepolymer composition is as described above.

[0281] (Thixotropic ratio)

[0282] The thixotropic ratio of the polymerizable prepolymer composition is preferably 1.3 or less, more preferably 1.2 or less, and further preferably 1.1 or less.

[0283] By making the thixotropic ratio of the polymerizable prepolymer composition 1.3 or less, the polymerizable prepolymer composition can be quickly filled into a polymerization container such as a mold, and the heat convection during polymerization can be suppressed, thereby further preventing the generation of ribs, etc. As a result, the generation of ribs, etc. can be suppressed in the obtained optical material, and the quality can be maintained well.

[0284] The thixotropic ratio of the polymerizable prepolymer composition is preferably 0.9 or more, more preferably 0.95 or more, and even more preferably 1.0 or more. The method for measuring the thixotropic ratio is as described above.

[0285] In the polymerizable prepolymer composition, from the viewpoint of handleability, the prepolymer may preferably contain an isocyanate group.

[0286] That is, it is preferred that not all isocyanate groups of the prepolymer are polymerized but only a part of them are polymerized. It is preferred that 70% or more of the isocyanate groups of the isocyanate compound used for producing the polymerizable prepolymer composition remain without being polymerized.

[0287] By making the prepolymer contain an isocyanate group, that is, by containing more isocyanate compounds than other optical material monomers that can be polymerized with isocyanate compounds, the viscosity of the polymerizable prepolymer composition can be kept low when the viscosity of the other optical material monomers is high, making it easy to handle.

[0288] In particular, when the prepolymer contains one or more selected from the group consisting of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane and pentaerythritol tetrakis(3-mercaptopropionate) as the above-mentioned other monomers for optical materials, it is preferred that the prepolymer contains an isocyanate group from the viewpoint of handleability.

[0289] In the polymerizable prepolymer composition, it is also preferred that the prepolymer does not substantially contain an isocyanate group.

[0290] In the present disclosure, the phrase “the prepolymer does not substantially contain isocyanate groups” means a state in which substantially all isocyanate groups are polymerized.

[0291] Specifically, the phrase “the prepolymer does not substantially contain an isocyanate group” means that the content of the isocyanate group in the prepolymer is below the detection limit when measured by an IR spectrometer.

[0292] When the prepolymer does not substantially contain an isocyanate group, since highly reactive isocyanate groups do not substantially exist, the stability of the polymerizable prepolymer composition can be improved.

[0293] With respect to the polymerizable prepolymer composition, the value obtained by subtracting the refractive index B of the prepolymer raw material composition (the prepolymer raw material composition is a composition before forming a prepolymer and is a composition comprising two or more different monomers for optical materials and a polymerization catalyst) from the refractive index A of the polymerizable prepolymer composition (also referred to as "refractive index A-refractive index B") is preferably greater than 0, more preferably greater than 0.005, and even more preferably greater than 0.01.

[0294] The refractive index A is the refractive index of the polymerizable prepolymer composition after obtaining the prepolymer by polymerizing the optical material monomer and the polymerization catalyst, and the refractive index B is the refractive index of the prepolymer raw material composition before obtaining the prepolymer by polymerizing the optical material monomer and the polymerization catalyst.

[0295] By making the refractive index A-refractive index B within the above range, the viscosity of the polymerizable prepolymer composition can be easily adjusted to a predetermined range. In addition, the quality (refractive index, appearance, etc.) of the cured product of the polymerizable prepolymer composition can be easily stabilized.

[0296] The refractive index A-refractive index B may be 0.04 or less, and may be 0.03 or less.

[0297] When the prepolymer contains an isocyanate group, the refractive index A-refractive index B is preferably 0.005 or more, more preferably 0.010 or more. In addition, the refractive index A-refractive index B is preferably 0.040 or less, more preferably 0.030 or less.

[0298] When the prepolymer contains substantially no isocyanate group, the refractive index A-refractive index B is preferably 0.005 or more, more preferably 0.010 or more. In addition, the refractive index A-refractive index B is preferably 0.035 or less, more preferably 0.025 or less.

[0299] The viscosity of the polymerizable prepolymer composition is preferably not easily changed over time (ie, stable). The term "stable viscosity of the polymerizable prepolymer composition" means that when the polymerizable prepolymer composition is stored at 20°C for 24 hours, the change in viscosity before and after the storage is 10% or less.

[0300] Examples of the polymerizable prepolymer composition having a stable viscosity include a polymerizable prepolymer composition that does not contain a polymerizable functional group that is easily polymerizable with a polymerizable functional group contained in the prepolymer.

[0301] "Solid Object"

[0302] The cured product of the present disclosure is a cured product of the above-mentioned polymerizable composition or polymerizable prepolymer composition.

[0303] The cured product of the present disclosure may contain an amine as a component derived from a polymerizable composition or a polymerizable prepolymer composition. For example, a cured product of a polymerizable composition or a polymerizable prepolymer composition containing an amine catalyst as a basic polymerization catalyst may contain an amine. The content of the amine contained in the cured product is not particularly limited, and for example, may be greater than 0% by mass and less than 1% by mass.

[0304] When the polymerizable composition or the polymerizable prepolymer composition contains an isocyanate compound having an aromatic ring as a monomer for an optical material and contains an amine catalyst as a basic polymerization catalyst, the content of amine in the cured product is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and further preferably 0.01% by mass or more, from the viewpoint of reducing ribs in the cured product.

[0305] From the viewpoint of improving the handleability of the polymerizable composition, the content of amine in the cured product is preferably 0.50 mass % or less, more preferably 0.20 mass % or less, and even more preferably 0.10 mass % or less.

[0306] When the polymerizable composition or the polymerizable prepolymer composition contains an isocyanate compound having no aromatic ring as a monomer for an optical material and contains an amine catalyst as a basic polymerization catalyst, from the viewpoint of reducing ribs in the cured product, the amine content in the cured product is preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.07% by mass or more.

[0307] From the viewpoint of improving the handleability of the polymerizable composition, the content of amine in the cured product is preferably 2.5% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less.

[0308] In the present disclosure, the amine content in the cured product is the amine content measured by gas chromatography-mass spectrometry from a dichloromethane composition obtained by dispersing the cured product in dichloromethane and subjecting the mixture to ultrasonic extraction.

[0309] The method for measuring the amine content in the cured product is as follows.

[0310] 200 mg of the solidified material formed into powder by a metal file and 3 mL of dichloromethane were placed in a centrifuge tube (volume 10 mL), and ultrasonic extraction was performed at room temperature for 10 minutes using an ultrasonic cleaner (manufactured by IUCHI, US-4). Centrifugal separation was performed at 4000 rpm for 10 minutes using a centrifuge (manufactured by KUBOTA, desktop small centrifuge 2410).

[0311] The supernatant was collected, and the residue was dispersed again in 3 mL of dichloromethane, and the above-mentioned ultrasonic extraction and centrifugal separation were performed to collect the supernatant (hereinafter also referred to as "residue extraction").

[0312] After the above-mentioned extraction of the residue was further performed twice, dichloromethane was added to the obtained supernatant to adjust the total amount to 10 mL.

[0313] The obtained 10 mL supernatant was filtered and analyzed by gas chromatography-mass spectrometry (also referred to as GC-MS) (GC-MS apparatus: Agilent, 6890GC / 5973NMSD, column: CP-Sil 8CB for Amine (0.25 mmID×30 mF.T=0.25 μm)) to obtain the peak area value derived from amines. A calibration curve of the obtained peak area value derived from amines and the amount of amines was prepared to measure the content of amines in the cured product.

[0314] It should be noted that the above-mentioned amine refers to an amine compound contained in the polymerizable composition or the polymerizable prepolymer composition as a basic polymerization catalyst, an active hydrogen compound, or the like.

[0315] The cured product of the present disclosure may contain an organic acid having a pKa value of less than 4 as a component derived from the polymerizable composition or the polymerizable prepolymer composition.

[0316] The content of the organic acid having a pKa value of less than 4 contained in the cured product is not particularly limited, and may be, for example, more than 0% by mass and not more than 1% by mass.

[0317] When the polymerizable composition or polymerizable prepolymer composition contains an isocyanate compound having an aromatic ring as a monomer for an optical material, the content of the organic acid having a pKa value of less than 4 in the cured product is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, from the viewpoint of increasing the pot life of the polymerizable composition or the polymerizable prepolymer composition and reducing striae in the cured product.

[0318] From the viewpoint of shortening the curing time of the polymerizable composition, the content of the organic acid having a pKa value of less than 4 in the cured product is preferably 1 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.1 mass % or less.

[0319] When the polymerizable composition or the polymerizable prepolymer composition contains an isocyanate compound having no aromatic ring as a monomer for an optical material, from the viewpoint of increasing the pot life of the polymerizable composition or the polymerizable prepolymer composition and reducing striae in the cured product, the content of the organic acid having a pKa value of less than 4 in the cured product is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more.

[0320] From the viewpoint of shortening the curing time of the polymerizable composition, the content of the organic acid having a pKa value of less than 4 in the cured product is preferably 5 mass % or less, more preferably 3 mass % or less, and even more preferably 1 mass % or less.

[0321] In the present disclosure, the content of the organic acid having a pKa value of less than 4 in the cured product is measured in the same manner as the above-mentioned content of the amine.

[0322] In particular, in optical applications requiring light transmittance, the devitrification of the cured product is preferably less than 50, more preferably less than 35.

[0323] The devitrification of the cured product was measured by the following method.

[0324] In a dark place, light from a light source (e.g., Luminar Ace LA-150A manufactured by Hayashi-Repic Co., Ltd.) is made to pass through the cured product. An image of the light passing through the cured product is collected into an image processing device (e.g., an image processing device manufactured by Ube Information Systems, Inc.), and the collected image is subjected to shading processing. The shading degree of the processed image is numerically converted for each pixel, and the value calculated as the average value of the shading degree of each pixel is used as the devitrification.

[0325] For the cured product, preferably there are no ribs longer than 1.0 mm within a radius of 15 mm from the center of the cured product, and more preferably there are no ribs longer than 1.0 mm within and outside a radius of 15 mm from the center of the cured product.

[0326] More specifically, the cured product may be a cured product of two or more different optical monomers, at least one of the two or more different optical material monomers is an isocyanate compound, there are no ribs with a length of more than 1.0 mm within a radius of 15 mm from the center of the cured product, the amine content measured by gas chromatography-mass spectrometry is greater than 0% by mass, and the content of organic acids with a pKa value of less than 4 measured by gas chromatography-mass spectrometry is greater than 0% by mass.

[0327] The content of amine measured by gas chromatography-mass spectrometry may be 1 mass % or less, and the content of organic acid having a pKa value of less than 4 measured by gas chromatography-mass spectrometry may be 1 mass % or less.

[0328] The preferred range of the content of the amine or the organic acid having a pKa value of less than 4 contained in the cured product is as described above.

[0329] The details and preferred embodiments of the two or more different monomers for optical materials and the isocyanate compound having an aromatic ring are as described above.

[0330] In the cured product of the present disclosure, the two or more different monomers for optical materials may include an isocyanate compound having an aromatic ring and an isocyanate compound not having an aromatic ring.

[0331] When two or more different monomers for optical materials include an isocyanate compound without an aromatic ring and an isocyanate compound with an aromatic ring, from the viewpoint of controlling the polymerization reaction, the ratio of the isocyanate compound without an aromatic ring to the isocyanate compound with an aromatic ring is preferably in the range of 3:7 to 0:10, more preferably in the range of 2:8 to 0:10, in terms of the molar ratio of the isocyanate group.

[0332] 《Methods for producing optical materials》

[0333] The method for producing an optical material of the present disclosure includes the following production method A and production method B.

[0334] <Production Method A>

[0335] Preparation method A includes: a preparation step of preparing a polymerizable composition, wherein the polymerizable composition comprises two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, wherein at least one of the two or more different monomers for optical materials is an isocyanate compound; a casting step of adjusting the viscosity of the polymerizable composition measured by a B-type viscometer at 25° C. and 60 rpm to 10 mPa·s to 1000 mPa·s, and casting the polymerizable composition for optical materials into a mold; and a curing step of curing the polymerizable composition by polymerizing the two or more different monomers for optical materials in the polymerizable composition in the mold.

[0336] The production method A includes the preparation step, the casting step, and the curing step, and thus can maintain the quality of the obtained optical material and shorten the production time of the optical material.

[0337] The manufacturing method A may include the preparation step, the casting step, and the curing step in sequence.

[0338] In the polymerizable composition prepared in the preparation step, the content of the basic polymerization catalyst relative to a total of 100 parts by mass of two or more different monomers for optical materials is not particularly limited. For example, the content of the basic polymerization catalyst relative to a total of 100 parts by mass of two or more different monomers for optical materials may be 0.010 parts by mass to 2.0 parts by mass.

[0339] The polymerizable composition having a basic polymerization catalyst content within the above range contains a larger amount of the basic polymerization catalyst than in conventional methods for producing optical materials.

[0340] Thus, when the optical material monomer in the polymerizable composition is polymerized in the curing step, reaction heat of the polymerizable composition (that is, heat generated by self-heating) can be generated in a short period of time.

[0341] The above-mentioned reaction heat can be utilized to promote the polymerization reaction of the monomer for optical material in the polymerizable composition, so that a high-quality optical material can be obtained in a shorter time than before.

[0342] In conventional methods, the polymerization reaction is mainly caused by heating the polymerizable composition. However, in Production Method A, heating of the polymerizable composition is not necessarily required.

[0343] In addition, the method A also utilizes the self-heating of the polymerizable composition, so the polymerization can be carried out without excessive reliance on the supply of heat from the outside. Therefore, while increasing the viscosity of the polymerizable composition described later, the thermal non-uniformity and thermal convection in the polymerizable composition can be suppressed, and the generation of ribs can be suppressed.

[0344] It should be noted that in the present disclosure, the so-called ribs are a state where the refractive index of a specific part is different from the normal refractive index of the surrounding part. In addition, it can also be described as a state that is disadvantageous in the desired use of the optical material. In optical materials, ribs are a kind of defect.

[0345] The content of the basic polymerization catalyst contained in the polymerizable composition can be determined according to the type of the isocyanate compound contained in the polymerizable composition. For example, the content of the basic polymerization catalyst can be determined according to the presence or absence of an aromatic ring in the isocyanate compound.

[0346] The preferred range of the content of the basic polymerization catalyst contained in the polymerizable composition is the same as the preferred range of the content of the basic polymerization catalyst contained in the above-mentioned polymerizable composition.

[0347] <Preparation process>

[0348] Preparation method A includes a preparation step of preparing a polymerizable composition, wherein the polymerizable composition includes two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid with a pKa value of less than 4, and at least one of the two or more different monomers for optical materials is an isocyanate compound.

[0349] The preparation step may be a step of simply preparing a polymerizable composition produced in advance, or may be a step of producing the polymerizable composition.

[0350] In the preparation step, the polymerizable composition may contain two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, and is not particularly limited.

[0351] As the polymerizable composition, an existing product may be used, or the composition may be prepared by mixing at least two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4. The mixing method is not particularly limited, and a known method may be applied.

[0352] The temperature when mixing the components of the polymerizable composition is not particularly limited, but is preferably 30° C. or lower, and more preferably room temperature (25° C.) or lower.

[0353] From the viewpoint of the pot life of the polymerizable composition, it is sometimes preferable to set the temperature to lower than 25° C. When additives such as an internal mold release agent have poor solubility in the above components, the above components may be heated in advance to dissolve the additives in the above components.

[0354] When mixing the above-mentioned components, it is preferably carried out under a dry inert gas in order to prevent moisture from being mixed into the polymerizable composition.

[0355] The preparation step is preferably a step of preliminarily mixing a basic polymerization catalyst and an organic acid having a pKa value of less than 4 with a portion of the two or more different monomers for optical materials, and then mixing the remaining two or more different monomers for optical materials to produce a polymerizable composition.

[0356] In this case, until a mixture containing a part of two or more different monomers for optical materials, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4 is mixed with a mixture containing no basic polymerization catalyst and an organic acid having a pKa value of less than 4 and containing the remaining part of two or more different monomers for optical materials, polymerization of a part of two or more different monomers for optical materials and the remaining part of two or more different monomers for optical materials can be prevented.

[0357] Therefore, by performing the preparation steps in the above order, the polymerization start time can be adjusted. Therefore, for example, the workability when injecting the polymerizable composition into the mold can be improved.

[0358] The mixing of the remainder of the two or more different monomers for optical material with the mixture containing a part of the two or more different monomers for optical material, a basic polymerization catalyst and an organic acid having a pKa value of less than 4 may be carried out at a single time or at multiple times.

[0359] As a specific aspect of the preparation step, for example, the following aspects can be mentioned.

[0360] First, a portion of the monomer for optical material and an additive (such as an internal mold release agent) are added to prepare a mixed solution. The mixed solution is stirred at 25° C. for 1 hour to completely dissolve the components, and then a portion of the remaining monomer for optical material is further added and stirred to prepare a uniform solution. The solution is degassed to obtain a first mixed solution.

[0361] Next, the remaining part of the monomer for optical material, the basic polymerization catalyst, and the organic acid with a pKa value of less than 4 were stirred at 25° C. for 30 minutes to completely dissolve them, thereby obtaining a second mixed solution.

[0362] Then, the first mixed liquid and the second mixed liquid are mixed to obtain a polymerizable composition.

[0363] <Casting process>

[0364] The production method A includes a casting step of adjusting the viscosity of the polymerizable composition measured by a Brookfield viscometer at 25° C. and 60 rpm to 10 mPa·s to 1000 mPa·s, and casting the composition into a mold.

[0365] By adjusting the viscosity of the polymerizable composition to be within the above range for casting, striae in the obtained optical material can be effectively suppressed.

[0366] From the above viewpoints, the viscosity of the polymerizable composition is 10 mPa·s or more, preferably 40 mPa·s or more, more preferably 70 mPa·s or more, further preferably 80 mPa·s or more, particularly preferably 100 mPa·s or more, and further preferably 120 mPa·s or more.

[0367] From the viewpoint of maintaining good workability when molding the optical material into a desired shape, the viscosity of the polymerizable composition is 1000 mPa·s or less, preferably 700 mPa·s or less, and more preferably 400 mPa·s or less.

[0368] The method for adjusting the viscosity of the polymerizable composition is not particularly limited.

[0369] For example, the viscosity of the polymerizable composition can be adjusted by adding a high-viscosity compound, heating, stirring, or the like.

[0370] <Curing process>

[0371] The production method A includes a curing step of curing the polymerizable composition by polymerizing the two or more different optical material monomers in the polymerizable composition in the mold.

[0372] Production method A includes a curing step, and thus the polymerizable composition can be polymerized to produce an optical material.

[0373] In conventional methods, the polymerizable composition is heated to cause a polymerization reaction. However, the polymerizable composition in Preparation A can promote the polymerization reaction of the monomers for optical materials in the polymerizable composition by increasing the reaction heat associated with the polymerization reaction (i.e., heat generated by self-heating).

[0374] That is, in the curing step of Production Method A, the polymerizable composition can be cured by leaving the polymerizable composition to stand.

[0375] Therefore, in the production method A, the polymerizable composition does not necessarily need to be heated, but the polymerizable composition may be heated in order to promote the polymerization reaction.

[0376] The environment in which the curing step is performed is not particularly limited, and curing can also be performed by heating from the outside of the mold. However, from the perspective of improving optical qualities such as ribs and polymerizing in a short period of time, a step of curing the polymerizable composition by leaving it to stand in a closed space is preferred.

[0377] By leaving the polymerizable composition still in a closed space, it is possible to prevent the heat generated by the self-heating of the polymerizable composition from being released to the outside. Thus, the heat generated by the self-heating can be kept in the closed space. As a result, the polymerization reaction can be more effectively promoted, and the optical material can be produced in a shorter time.

[0378] As a closed space, a heat-insulating environment is mentioned, for example.

[0379] The so-called heat-insulating environment refers to an environment in which heat is retained inside and heat conduction between the inside and the outside is suppressed. The so-called environment in which heat conduction between the inside and the outside is suppressed refers to an environment in which, when the polymerizable composition is left to stand in a closed space, the heat conductivity between the inside and the outside of the closed space is such that the polymerizable composition can be cured.

[0380] The heat-insulating environment can be formed using, for example, a heat-insulating material.

[0381] That is, by leaving the polymerizable composition at rest in a heat-insulating container formed of a heat-insulating material, heat can be retained inside the heat-insulating container, and heat conduction between the inside and the outside can be suppressed.

[0382] The thermal conductivity of the heat insulating material is preferably 0.50 W / mK or less, more preferably 0.10 W / mK or less, and further preferably 0.05 W / mK or less.

[0383] The density of the insulation material is preferably 10 kg / m 3 More preferably 15kg / m 3 More preferably, 20 kg / m 3 above.

[0384] In the "insulation" or "insulation environment" in Preparation A, it is preferred to heat the insulated reaction tank to a constant temperature state (constant temperature reaction tank) within a range that does not hinder the polymerization reaction based on the reaction heat of the polymerizable composition or does not excessively promote the polymerization reaction of the polymerizable composition due to external heating.

[0385] Thus, the environment in the reaction vessel where the mold is placed can be kept warm or kept constant temperature by the temperature rise due to the self-heating of the monomer for optical material, so the polymerization reaction can be promoted more effectively.

[0386] As the heat-insulating environment, for example, the above-mentioned heat-insulating reaction tank or constant-temperature reaction tank can be used.

[0387] For example, when the mold injected with the monomer is left to stand in a vacuum container as an adiabatic reaction tank, adiabatic polymerization in an adiabatic environment using the adiabatic reaction tank (constant temperature reaction tank) can be performed by the following procedure.

[0388] The inner side of the vacuum container is covered with a heat-insulating and heat-retaining member such as polyurethane foam or cork, and the mold injected with the monomer is wrapped with a member such as cloth as needed. Then, the mold injected with the monomer is left to stand in the vacuum container.

[0389] The curing step may be a step of curing the polymerizable composition by leaving the polymerizable composition to stand without external heating.

[0390] As described above, in the preparation method A, heating of the polymerizable composition is not necessarily required.

[0391] In order to heat from the outside, a device may be used, and the economic burden may increase. According to the production method A, the optical material can be produced by a simple method, so the economic burden can be reduced.

[0392] The curing step is preferably a step of curing the polymerizable composition by leaving the polymerizable composition to stand for 2 to 10 hours.

[0393] According to the conventional method, the polymerization reaction is generally carried out over several hours to several tens of hours (for example, about 20 hours to 48 hours) while gradually raising the temperature by heating.

[0394] When the polymerization reaction is performed for a short time, the polymerizable composition is not completely cured, so that an optical material cannot be obtained or the quality of the optical material is reduced.

[0395] However, according to Production Method A, the optical material can be produced in a short time while maintaining the quality of the obtained optical material. Specifically, the optical material can be produced by leaving the polymerizable composition to stand for 10 hours or less.

[0396] From the above viewpoints, in the curing step, it is more preferred that the polymerizable composition be left to stand for 8 hours or less.

[0397] In addition, from the viewpoint of allowing the polymerization reaction to proceed and obtaining a well-cured optical material, the polymerizable composition is preferably allowed to stand for 2 hours or more, more preferably for 5 hours or more.

[0398] In the curing step, a microwave irradiation step of irradiating the polymerizable composition with microwaves for a predetermined time may be provided as necessary.

[0399] As one aspect of the curing step, there is mentioned an aspect including the following steps a and b.

[0400] Step a: Inject (cast) the polymerizable composition into a casting mold (inside the cavity of a mold).

[0401] Step b: The mold into which the polymerizable composition has been injected is left to stand in a closed space for a predetermined period of time to perform heat-insulating polymerization.

[0402] (Process a)

[0403] First, the polymerizable composition is injected into a molding die (casting mold) held by a gasket or tape, etc. At this time, degassing treatment under reduced pressure, filtration treatment under pressure or reduced pressure, etc. are preferably performed as needed, depending on the physical properties required for the obtained optical material.

[0404] (Process b)

[0405] The polymerization conditions are not limited, but are preferably appropriately adjusted according to the composition of the polymerizable composition, the type and amount of the catalyst used, the shape of the mold, and the like.

[0406] The mold into which the polymerizable composition has been injected can be left to stand in a heat-insulating environment for 2 to 4 hours to perform polymerization.

[0407] In step b, if necessary, a heating step may be added after the heat insulation polymerization process in which the mold into which the polymerizable composition is injected is left to stand for a certain period of time in a heat insulation environment.

[0408] In step b, as needed, in parallel with the step of leaving the mold injected with the polymerizable composition to stand in an insulating environment (insulating polymerization), the mold injected with the polymerizable composition may be heated continuously or intermittently at a temperature not higher than the self-heating temperature emitted by the polymerizable composition in the insulating polymerization process, or the inside of the insulating reaction tank may be heated to keep the ambient temperature in the insulating reaction tank warm.

[0409] <Annealing process>

[0410] The preparation method A may include an annealing step of annealing the cured polymerizable composition as required.

[0411] The annealing treatment is usually performed at a temperature of 50 to 150°C, preferably 90 to 140°C, and more preferably 100 to 130°C.

[0412] <Other Process>

[0413] Preparation method A can be provided with other steps as required.

[0414] As another step, when an optical material is produced using a mold, for example, there is mentioned an injection step of injecting the polymerizable composition into the mold.

[0415] <Applications of optical materials>

[0416] The optical material in the preparation method A can be used for plastic lenses, edges, optical fibers, information recording substrates, optical filters, light-emitting diodes, and the like.

[0417] Among the above, the optical material in the embodiment of the present disclosure can be suitably used for a plastic lens, and can be more suitably used for a plastic lens for spectacles.

[0418] <Method B>

[0419] Preparation method B includes:

[0420] A preparation step of preparing two or more different monomers for optical materials and a basic polymerization catalyst;

[0421] a prepolymerization step of mixing a part of the two or more different monomers for optical materials with at least a part of the basic polymerization catalyst, polymerizing at least a part of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing the prepolymer; and

[0422] an acid adding step, adding an organic acid having a pKa value of less than 4 to the mixture containing the prepolymer;

[0423] At least one of the two or more different monomers for an optical material is an isocyanate compound.

[0424] The production method B includes a preparation step, a prepolymerization step, and an acid addition step, so that striae in the obtained optical material can be suppressed and the production time of the optical material can be shortened.

[0425] In addition to the above steps, the method B preferably further comprises:

[0426] a polymerizable composition production step, comprising adding at least the remaining portion of the two or more different monomers for optical materials to a mixture containing the prepolymer, thereby obtaining a polymerizable composition containing two or more different monomers for optical materials, a prepolymer, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4; and

[0427] The curing step is to obtain an optical material as a cured product of the polymerizable composition by curing two or more different monomers for an optical material in the polymerizable composition.

[0428] Since the production method B further includes a polymerizable composition production step and a curing step, striae in the obtained optical material can be more effectively suppressed and the production time of the optical material can be more effectively shortened.

[0429] In the preparation step, the content of the basic polymerization catalyst relative to 100 parts by mass of the total of two or more different monomers for optical materials is not particularly limited. For example, the content of the basic polymerization catalyst relative to 100 parts by mass of the total of two or more different monomers for optical materials can be 0.010 parts by mass to 2.0 parts by mass.

[0430] The polymerizable composition having a basic polymerization catalyst content within the above range contains a larger amount of the basic polymerization catalyst than in conventional methods for producing optical materials.

[0431] Therefore, similarly to the case of the manufacturing method A, a high-quality optical material with suppressed striae can be obtained in a shorter time than before.

[0432] Similar to the case of the production method A, in the production method B, heating of the polymerizable composition for an optical material is not necessarily required.

[0433] The production method B includes a preparation step, a prepolymerization step, a polymerizable composition production step, and a curing step, and can suppress convection in the mold where the polymerization reaction is performed, and can suppress the generation of striae in the obtained cured product.

[0434] Furthermore, since the production method B includes the prepolymerization step, the storage stability of the mixture (for example, the polymerizable composition) can be maintained more satisfactorily compared to the case where the prepolymerization is not involved.

[0435] For example, when a mixture containing a prepolymer is stored for a certain period of time, the polymerization reaction in the mixture can be suppressed. That is, a longer pot life can be ensured.

[0436] Furthermore, by adding an organic acid having a pKa value of less than 4 to the mixture containing the prepolymer in the acid adding step, the activity of the basic polymerization catalyst is suppressed, and the pot life of the polymerizable composition is further improved.

[0437] <Preparation process>

[0438] The production method B includes a preparation step of preparing two or more different monomers for optical materials and a basic polymerization catalyst.

[0439] The amount of the basic polymerization catalyst in the preparation step can be determined according to the type of isocyanate compound contained in the two or more different monomers for optical materials. For example, the amount of the basic polymerization catalyst can be determined according to the presence or absence of an aromatic ring in the isocyanate compound.

[0440] When at least one of the two or more different monomers for an optical material is an isocyanate compound having an aromatic ring, the amount of the basic polymerization catalyst may be 0.010 to 0.50 parts by mass based on 100 parts by mass of the two or more different monomers for an optical material.

[0441] By using 0.010 mass parts or more of a basic polymerization catalyst relative to 100 mass parts of two or more different optical material monomers, the polymerization reaction can be well promoted, so that a high-quality optical material with suppressed ribs can be obtained in a short time. In addition, by well promoting the polymerization reaction, the demolding property of the cured product when it is taken out of the mold can be improved.

[0442] From the above viewpoints, the basic polymerization catalyst is used in an amount of preferably 0.015 parts by mass or more, more preferably 0.030 parts by mass or more, based on 100 parts by mass of the two or more different monomers for an optical material.

[0443] The above-mentioned range of the content of the basic polymerization catalyst can be appropriately changed according to the types of the monomer for optical material and the basic polymerization catalyst.

[0444] For example, when the monomers for optical materials include meta-xylylene diisocyanate (an isocyanate compound having an aromatic ring), 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and the basic polymerization catalyst includes 3,5-lutidine, the basic polymerization catalyst is preferably used in an amount of 0.015 parts by mass or more, and more preferably 0.020 parts by mass or more, relative to 100 parts by mass of the two or more different monomers for optical materials.

[0445] For example, when the monomers for optical materials include meta-xylylenediisocyanate and 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and the basic polymerization catalyst includes 3,5-lutidine, the basic polymerization catalyst is preferably used in an amount of 0.010 parts by mass or more, more preferably 0.015 parts by mass or more, relative to 100 parts by mass of the two or more different monomers for optical materials.

[0446] By using 0.50 parts by mass or less of the basic polymerization catalyst based on 100 parts by mass of two or more different monomers for an optical material, for example, workability when injecting the polymerizable composition into a mold can be improved.

[0447] From the above viewpoints, the amount of the basic polymerization catalyst is preferably 0.09 parts by mass or less, more preferably 0.07 parts by mass or less, and even more preferably 0.05 parts by mass or less, based on 100 parts by mass of the two or more different monomers for an optical material.

[0448] When at least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, the amount of the basic polymerization catalyst may be greater than 0.05 parts by mass and less than 2.0 parts by mass relative to a total of 100 parts by mass of the two or more different monomers for optical materials.

[0449] By using more than 0.05 parts by mass of a basic polymerization catalyst relative to 100 parts by mass of two or more different monomers for optical materials, the polymerization reaction can be well promoted, so that a high-quality optical material with suppressed ribs can be obtained in a short time. In addition, by well promoting the polymerization reaction, the demolding property of the cured product when it is taken out of the mold can be improved.

[0450] From the above viewpoints, the amount of the basic polymerization catalyst is preferably 0.08 parts by mass or more, more preferably 0.10 parts by mass or more, further preferably 0.13 parts by mass or more, and particularly preferably 0.17 parts by mass or more, based on 100 parts by mass of the two or more different monomers for optical materials.

[0451] The above-mentioned range of the content of the basic polymerization catalyst can be appropriately changed according to the types of the monomer for optical material and the basic polymerization catalyst.

[0452] For example, when the monomers for optical materials include 2,5(6)-bis(isocyanatemethyl)-bicyclo-[2.2.1]-heptane, pentaerythritol tetrakis(3-mercaptopropionate), and 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, and the polymerization catalyst includes 3,5-lutidine, the polymerization catalyst is preferably used in an amount of 0.10 parts by mass or more, and more preferably 0.17 parts by mass or more, relative to 100 parts by mass of the two or more different monomers for optical materials.

[0453] By using 2.0 parts by mass or less of the basic polymerization catalyst based on 100 parts by mass of two or more different monomers for an optical material, for example, workability when injecting the polymerizable composition into a mold can be improved.

[0454] From the above viewpoints, the amount of the basic polymerization catalyst is preferably 1.5 parts by mass or less based on 100 parts by mass of the two or more different monomers for an optical material.

[0455] Depending on the types of the optical material monomers and the basic polymerization catalyst, the amount of the basic polymerization catalyst may be 1.0 part by mass or less, 0.3 part by mass or less, or 0.15 part by mass or less relative to 100 parts by mass of two or more different optical material monomers.

[0456] The amount of the basic polymerization catalyst can be appropriately set depending on the type of the basic polymerization catalyst, the type and amount of monomers used (isocyanate compound, active hydrogen compound, other components, etc.), the shape of the desired molded product, and the like.

[0457] <Prepolymerization process>

[0458] Preparation method B includes a prepolymerization step, that is, mixing a part of two or more different monomers for optical materials with at least a part of a basic polymerization catalyst, polymerizing at least a part of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing a prepolymer.

[0459] The inventors of the present application believe that convection occurs due to uneven temperature distribution in a mold where a polymerization reaction is performed, which is one of the causes of striae in the obtained cured product.

[0460] Therefore, the inventors of the present application have focused on increasing the viscosity of the polymerizable composition for optical materials by polymerizing a part of the monomers for optical materials in advance to produce a prepolymer and making the polymerizable composition contain the prepolymer. This can suppress convection in the mold.

[0461] In the manufacturing method B, since the self-heat is not dissipated to the outside, the temperature difference between the inside and the periphery of the mold can be less likely to occur.

[0462] Based on the above viewpoints, it is estimated that the production method B can suppress striae in the obtained cured product.

[0463] According to the production method B, a prepolymer having an excellent pot life can be obtained.

[0464] The aspect of “a part of two or more different monomers for optical materials” is not particularly limited.

[0465] For example, “a part of two or more different monomers for an optical material” may be an amount of a part of each of two or more different monomers for an optical material.

[0466] Furthermore, “a part of two or more different monomers for an optical material” may be all of one or more of the two or more different monomers for an optical material.

[0467] The basic polymerization catalyst used in the prepolymerization step may be a part of the basic polymerization catalyst contained in the polymerizable composition or may be the whole of the basic polymerization catalyst.

[0468] When a part of the basic polymerization catalyst contained in the polymerizable composition is used in the prepolymerization step, the form of "a part of the basic polymerization catalyst" is not particularly limited, similarly to "a part of two or more different monomers for optical materials".

[0469] For example, "a part of the basic polymerization catalyst" may be an amount of a part of the basic polymerization catalyst.

[0470] When used as a part of the basic polymerization catalyst, from the viewpoint of ensuring a long-term pot life, the part of the basic polymerization catalyst is preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 15 to 50 parts by mass in 100 parts by mass of the basic polymerization catalyst.

[0471] From the viewpoint of ensuring a long-term shelf life, a portion of the two or more different monomers for optical materials is preferably 5 to 95 parts by mass, more preferably 20 to 80 parts by mass, and further preferably 30 to 70 parts by mass, out of 100 parts by mass of the two or more different monomers for optical materials.

[0472] Although examples of specific aspects of the prepolymerization step are shown below, the prepolymerization step in the production method B is not limited to the following aspects.

[0473] (Method a)

[0474] The prepolymerization step of embodiment a is a step of mixing a part of two or more different monomers for optical materials and the whole of a basic polymerization catalyst, polymerizing at least a part of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing the prepolymer.

[0475] In embodiment a, part of the two or more different monomers for optical materials preferably consists of the whole of one of the two or more different monomers for optical materials and part of other monomers for optical materials excluding the one.

[0476] (Method b)

[0477] The prepolymerization step of embodiment b is a step of mixing parts of two or more different monomers for optical materials and part of a basic polymerization catalyst, polymerizing at least part of the parts of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing the prepolymer.

[0478] When the preparation method B includes the prepolymerization step of method b, the polymerizable composition production step described later is the following step: by adding at least the remaining part of two or more different monomers for optical materials and the remaining part of the basic polymerization catalyst to the mixture containing the prepolymer, a polymerizable composition containing two or more different monomers for optical materials, a prepolymer, a basic polymerization catalyst, and an organic acid with a pKa value of less than 4 is obtained.

[0479] In embodiment b, preferably, the two or more different monomers for optical materials contain an isocyanate compound, a part of the two or more different monomers for optical materials contain a part of the isocyanate compound, and the rest of the two or more different monomers for optical materials contain the rest of the isocyanate compound.

[0480] <Acid Addition Process>

[0481] Preparation method B includes an acid adding step of adding an organic acid having a pKa value of less than 4 to a mixture containing a prepolymer.

[0482] There is no particular limitation on the amount of the organic acid having a pKa value of less than 4 added to the mixture containing the prepolymer. For example, the content of the organic acid having a pKa value of less than 4 may be 0.001 to 1 parts by mass based on 100 parts by mass of the total of two or more different monomers for optical materials that are raw materials of the prepolymer.

[0483] When the content of the organic acid having a pKa value of less than 4 is 0.001 parts by mass or more based on 100 parts by mass of the total of two or more different monomers for an optical material, an increase in the viscosity of the polymerizable composition can be effectively suppressed.

[0484] From the above viewpoints, the content of the organic acid having a pKa value of less than 4 is preferably 0.005 parts by mass or more, and more preferably 0.01 parts by mass or more, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0485] When the content of the organic acid having a pKa value of less than 4 is 1 part by mass or less relative to 100 parts by mass of the total of two or more different monomers for optical materials, the salt formed by the organic acid and the basic polymerization catalyst is promoted to dissociate under the action of heat in the curing step, and the basic polymerization catalyst is easily activated. Thus, the polymerization reaction can be rapidly carried out.

[0486] From the above viewpoints, the content of the organic acid having a pKa value of less than 4 is preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total of two or more different monomers for an optical material.

[0487] The molar ratio (X / Y) of the organic acid (X) having a pKa value of less than 4 to the basic polymerization catalyst (Y) is preferably 0.1 to 2.0, more preferably 0.15 to 1.25, and even more preferably 0.2 to 1.2.

[0488] From the viewpoint of exhibiting good activity of the basic polymerization catalyst, the molar number (x) of the functional group of the organic acid having a pKa value of less than 4 in the mixture containing the prepolymer is preferably smaller than the molar number (y) of the functional group of the basic polymerization catalyst (the molar ratio represented by x / y is less than 1.0).

[0489] <Viscosity adjustment process>

[0490] The production method B preferably includes a viscosity adjustment step of adjusting the viscosity of the mixture containing the prepolymer to 30 mPa·s to 2000 mPa·s after the prepolymerization step and before the polymerizable composition production step.

[0491] By setting the viscosity of the mixture containing the prepolymer within the above range, the viscosity of the polymerizable composition produced in the polymerizable composition production step can be set within an appropriate range from the viewpoint of suppressing striae in the obtained optical material. As a result, striae in the obtained optical material can be suppressed.

[0492] From the above viewpoints, the viscosity of the mixture containing the prepolymer is preferably 40 mPa·s to 2000 mPa·s, and more preferably 50 mPa·s to 1800 mPa·s.

[0493] The above viscosity is measured using a B-type viscometer under the conditions of 25° C. and 60 rpm (revolutions per minute).

[0494] There are no particular limitations on the method for adjusting the viscosity of the mixture containing the prepolymer.

[0495] For example, the viscosity of the mixture containing the prepolymer can be adjusted by adding a high-viscosity compound, heating, stirring, or the like.

[0496] The temperature when preparing the mixture containing the prepolymer is not particularly limited as long as it is a temperature at which the prepolymer can be obtained by the polymerization reaction, and may be, for example, 20°C to 50°C, or 25°C to 45°C.

[0497] The stirring time for preparing the mixture containing the prepolymer is not particularly limited as long as it is a stirring time that can obtain the prepolymer by the polymerization reaction, and may be, for example, 30 minutes to 5 hours, or 1 hour to 5 hours.

[0498] As a method for preparing a mixture containing a prepolymer, specifically, a method of preparing a mixture containing a prepolymer while adjusting the viscosity by stirring at 40° C. for 3 hours may be employed.

[0499] <Polymerizable composition production process>

[0500] Preparation method B includes the following polymerizable composition production step: by adding the remaining part of at least two different monomers for optical materials to a mixture containing a prepolymer, thereby obtaining a polymerizable composition containing two or more different monomers for optical materials, a prepolymer, a basic polymerization catalyst, and an organic acid with a pKa value of less than 4.

[0501] The polymerizable composition production process is a process of adding at least the remainder of two or more different monomers for optical materials to a mixture containing a prepolymer, thereby obtaining a polymerizable composition for optical materials containing two or more different monomers for optical materials, a prepolymer, a basic polymerization catalyst, and an organic acid with a pKa value of less than 4.

[0502] Thus, until the mixture containing the prepolymer and the remaining part of the two or more different monomers for an optical material are mixed, the prepolymer and the remaining part of the two or more different monomers for an optical material can be prevented from being polymerized.

[0503] Therefore, by performing the polymerizable composition production step at an appropriate time, for example, the workability when injecting the polymerizable composition into a mold can be improved.

[0504] In the step of producing the polymerizable composition, when the remaining portion of at least two or more different monomers for an optical material are added to the mixture including the prepolymer, the addition may be carried out at a single time or in multiple times.

[0505] It should be noted that the “remaining part of two or more different monomers for optical materials” refers to the remaining part of the two or more different monomers for optical materials with respect to “a part of the two or more different monomers for optical materials” in the prepolymerization step.

[0506] The "remaining part of two or more different monomers for optical materials" may also be the following monomers for optical materials: they have functional groups that can be polymerized with the polymerizable functional groups of the prepolymer, and the amount of the functional groups that can be polymerized with the polymerizable functional groups of the prepolymer is an amount that can substantially polymerize with all the polymerizable functional groups of the prepolymer (i.e., an equivalent amount).

[0507] From the viewpoint of improving the optical uniformity of the polymerizable composition, the remainder of the two or more different monomers for an optical material preferably includes the same monomer as the monomer for an optical material constituting the prepolymer.

[0508] The temperature at which the above-mentioned components are mixed is not particularly limited, but is preferably 30° C. or lower, and more preferably room temperature (25° C.) or lower.

[0509] The temperature when mixing the components is preferably set lower than 25° C. However, when additives such as an internal mold release agent have poor solubility in the above components, the above components may be heated in advance to dissolve the additives in the above components.

[0510] As specific aspects of the polymerizable composition production process, the following aspects can be mentioned.

[0511] First, an organic acid with a pKa value of less than 4 and other additives (such as an internal mold release agent) are added to a mixture containing a prepolymer to prepare a mixed solution. The mixed solution is stirred at 25° C. for 1 hour to completely dissolve the components, and then degassed to obtain a first mixed solution.

[0512] Separately, the remaining portion of the monomer for optical material and the remaining portion of the basic polymerization catalyst added as required were stirred at 25° C. for 30 minutes to completely dissolve them, thereby obtaining a second mixed liquid.

[0513] Then, the first mixed liquid and the second mixed liquid are mixed, stirred, and then degassed to obtain a polymerizable composition.

[0514] <Liquid feeding process>

[0515] The production method B may further include a step of sending a liquid of the polymerizable composition to a casting mold after the step of producing the polymerizable composition and before the step of curing.

[0516] The liquid feeding step may be a step of feeding the polymerizable composition to the casting mold while remixing the polymerizable composition in a static mixer.

[0517] The liquid feeding step may be a step of feeding the polymerizable composition to the casting mold while remixing the polymerizable composition using a dynamic mixer. If the polymerizable composition is fed while remixing, the uneven distribution of the polymerizable composition can be eliminated during the feeding of the polymerizable composition to the casting mold. Therefore, striae in the obtained cured product can be suppressed.

[0518] <Curing process>

[0519] The production method B includes a curing step of obtaining an optical material as a cured product of the polymerizable composition by curing two or more different monomers for an optical material in the polymerizable composition.

[0520] Specific aspects and preferred aspects of the curing step in the production method B are the same as those described in the section "Curing step" in the above-mentioned production method A.

[0521] <Second prepolymerization step>

[0522] As for the preparation method B, in addition to the above steps, it may also include:

[0523] A second prepolymerization step of mixing the remaining portions of the two or more different optical material monomers with the remaining portion of the basic polymerization catalyst to polymerize at least a portion of the remaining portions of the two or more different optical material monomers to obtain a second prepolymer, thereby obtaining a mixture containing the second prepolymer;

[0524] a polymerizable composition production step of adding the mixture containing the second prepolymer to the mixture containing the prepolymer obtained in the prepolymerization step, thereby obtaining a polymerizable composition containing the prepolymer, the second prepolymer, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4; and

[0525] The curing step is to obtain an optical material which is a cured product of the polymerizable composition by curing the prepolymer and the second prepolymer in the polymerizable composition.

[0526] According to the production method B, by including the above-mentioned configuration, a mixture containing a prepolymer obtained in the prepolymerization step and a mixture containing a second prepolymer obtained in the second prepolymerization step can be obtained.

[0527] This allows the viscosity of the mixture containing the prepolymer and the viscosity of the mixture containing the second prepolymer to be close to each other, and therefore, the two can be mixed more easily.

[0528] In the second prepolymerization step, specific aspects and preferred aspects of the two or more different monomers for optical material and the basic polymerization catalyst are the same as those in the prepolymerization step.

[0529] When the preparation method B includes a second prepolymerization step, in the polymerizable composition production step, the mixture containing the second prepolymer is added to the mixture containing the prepolymer obtained in the prepolymerization step, thereby obtaining a polymerizable composition containing the prepolymer, the second prepolymer, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4.

[0530] In the polymerizable composition production step, specific aspects and preferred aspects of the mixture containing the prepolymer are the same as those in the above-mentioned <polymerizable composition production step>.

[0531] When the production method B includes the second prepolymerization step, the curing step is a step of obtaining an optical material as a cured product of the polymerizable composition by curing the prepolymer and the second prepolymer in the polymerizable composition.

[0532] In the curing step, specific aspects and preferred aspects of the prepolymer are the same as those of the prepolymer in the above-mentioned <curing step>.

[0533] <Annealing process>

[0534] The preparation method B may include an annealing step of annealing the cured polymerizable composition as required.

[0535] The specific aspects and preferred aspects of the annealing step in the production method B are the same as those of the annealing step in the production method A.

[0536] <Other Process>

[0537] Preparation method B can be provided with other steps as required.

[0538] The specific aspects and preferred aspects of the other steps in Preparation B are the same as those in Preparation A.

[0539] <Applications of optical materials>

[0540] The specific aspects and preferred aspects of the use of the optical material in the production method B are the same as those in the production method A.

[0541] Example

[0542] Hereinafter, examples of the present disclosure are shown, but the present disclosure is not limited to the following examples. It should be noted that, unless otherwise specified, "parts" are based on mass.

[0543] [Example 1-1]

[0544] 1.50 parts by mass of Tinuvin 329 [ultraviolet absorber] manufactured by BASF and 43.80 parts by mass of m-xylylene diisocyanate [monomer a1 for optical materials] were mixed and stirred at 25°C for 1 hour to completely dissolve the mixture to obtain a mixed solution. 10.56 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] was added to the mixed solution and stirred at 25°C for 5 minutes to obtain a uniform solution. 0.028 parts by mass of 3,5-lutidine [basic polymerization catalyst, pKa value = 6.15] was added to the obtained solution and stirred at 40°C for 1 hour to polymerize the monomer for optical materials to obtain a mixture containing a prepolymer.

[0545] 3.00 parts by mass of m-xylylene diisocyanate [monomer a1 for optical materials], 0.1 parts by mass of JP-506H [mold release agent] manufactured by Johoku Chemical Industry Co., Ltd., and 0.029 parts by mass of (±)-10-camphorsulfonic acid [organic acid, pKa value = 1.17] were mixed to prepare a mixed solution. The mixed solution was mixed with the mixture containing the prepolymer described above, and degassed under the conditions of 400 Pa and 25° C. for 1 hour to obtain a mixture 1 containing the prepolymer.

[0546] Table 1 shows the viscosity and refractive index of the mixture 1 including the prepolymer.

[0547] 5.20 parts by mass of m-xylylene diisocyanate [monomer a1 for optical materials] and 37.44 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] were mixed and stirred at 25°C for 5 minutes to obtain a uniform solution. 0.01 parts by mass of 3,5-lutidine [basic polymerization catalyst, pKa value = 6.15] was added to the obtained uniform solution and stirred at 40°C for 1 hour to polymerize the monomer for optical materials. Then, deaeration was performed at 400 Pa and 25°C for 1 hour to obtain a mixture 2 containing a prepolymer.

[0548] Table 1 shows the viscosity of the mixture 2 containing the prepolymer.

[0549] Mixture 1 containing a prepolymer and mixture 2 containing a prepolymer were mixed at 20° C. to obtain a polymerizable composition. The obtained polymerizable composition was fed into a casting mold (ie, a mold) while being remixed in a static mixer.

[0550] The viscosity of the polymerizable composition when it was sent to the mold and cast (also referred to as casting viscosity) was adjusted to the value shown in Table 1.

[0551] When feeding the liquid, the polymerizable composition was filtered with a 1μm PTFE filter and injected into the mold cavity at a rate of 10g / second. The mold consisted of a 4-curve glass mold (upper mold) with a diameter of 78mm and a 4-curve glass mold (lower mold) with a diameter of 78mm and a cavity for lens production.

[0552] The mold with the polymerizable composition injected was placed in a polymerization oven and heated from 20° C. to 120° C. over 10 hours. The molded body in a cured state of the polymerizable composition was released from the mold and annealed at 120° C. for 2 hours to obtain a molded body (lens).

[0553] [Example 1-2]

[0554] A molded product (lens) was obtained by the same method as in Example 1-1 except that the method for preparing the mixture 1 containing the prepolymer was changed as follows.

[0555] 1.50 parts by mass of Tinuvin 329 [ultraviolet absorber] manufactured by BASF and 46.80 parts by mass of m-xylylene diisocyanate [monomer a1 for optical materials] were mixed and stirred at 25°C for 1 hour to completely dissolve the mixture to obtain a mixed solution. 10.56 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] was added to the mixed solution and stirred at 25°C for 5 minutes to obtain a uniform solution. 0.028 parts by mass of 3,5-lutidine [basic polymerization catalyst] was added to the obtained uniform solution and stirred at 40°C for 1 hour to polymerize the monomer for optical materials to obtain a mixture containing a prepolymer.

[0556] 0.1 parts by mass of JP-506H (release agent) manufactured by Johoku Chemical Industry Co., Ltd. and 0.007 parts by mass of methanesulfonic acid (organic acid, pKa value = -2.6) were mixed with the above mixture containing the prepolymer, and degassed at 400 Pa and 25° C. for 1 hour to obtain mixture 1 containing the prepolymer.

[0557] Table 1 shows the viscosity and refractive index of the mixture 1 including the prepolymer.

[0558] [Examples 1-3]

[0559] A molded body (lens) was obtained in the same manner as in Example 1-1 except that the basic polymerization catalyst was changed from 3,5-lutidine to 2,6-lutidine [basic polymerization catalyst, pKa value = 6.6] and the amount of organic acid added was changed to 0.025 parts by mass.

[0560] [Examples 1-4]

[0561] A molded body (lens) was obtained by the same method as in Example 1-1 except that the mixture 1 containing a prepolymer and the mixture 2 containing a prepolymer were changed to those shown in Table 1.

[0562] Specifically, the monomer for optical material used in the preparation of the mixture 1 containing the prepolymer and the mixture 2 containing the prepolymer was changed from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer for optical material b1] to a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane [monomer for optical material b2], and the amount of each component was changed to the amount shown in Table 1.

[0563] [Examples 1-5]

[0564] Except having changed the mixture 1 containing a prepolymer and the mixture 2 containing a prepolymer into the thing shown in Table 1, it carried out similarly to Example 1-2, and obtained the molded body (lens).

[0565] Specifically, the monomer for optical material used in the preparation of the mixture 1 containing the prepolymer and the mixture 2 containing the prepolymer was changed from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer for optical material b1] to a mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane [monomer for optical material b2], and the amount of each component was changed to the amount shown in Table 1.

[0566] [Comparative Example 1-1]

[0567] A molded body (lens) was obtained by the same method as in Example 1-1 except that (±)-10-camphorsulfonic acid was not used in the preparation of the mixture 1 containing the prepolymer.

[0568] [Comparative Example 1-2]

[0569] A molded body (lens) was obtained in the same manner as in Example 1-1, except that octanoic acid [organic acid, pKa value = 4.90] was used instead of (±)-10-camphorsulfonic acid in the preparation of the mixture 1 containing the prepolymer.

[0570] [Comparative Examples 1-3]

[0571] A molded body (lens) was obtained by the same method as in Example 1-3 except that (±)-10-camphorsulfonic acid was not used in the preparation of the mixture 1 containing the prepolymer.

[0572] [Comparative Examples 1-4]

[0573] A molded body (lens) was obtained by the same method as in Example 1-3 except that octanoic acid was used instead of (±)-10-camphorsulfonic acid in the preparation of the mixture 1 containing the prepolymer.

[0574] [Example 2-1]

[0575] 0.10 parts by mass of an internal mold release agent for MR manufactured by Mitsui Chemicals, Inc. [internal mold release agent], 1.5 parts by mass of Tinuvin 329 manufactured by BASF [ultraviolet absorber], and 43.07 parts by mass of a mixture of 2,5-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane [monomer a1 for optical materials] were mixed, stirred at 25° C. for 1 hour to completely dissolve the mixture, thereby obtaining a mixed solution. 3.47 parts by mass of pentaerythritol tetrakis(3-mercaptopropionate) [monomer b2 for optical materials] and 3.70 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] were added to the mixed solution, and stirred at 25° C. for 5 minutes to obtain a uniform solution. To the obtained uniform solution, 0.13 parts by mass of 3,5-lutidine [basic polymerization catalyst, pKa value = 6.15] was added, and the mixture was stirred at 40° C. for 3 hours to polymerize the monomer for an optical material, thereby obtaining a mixture containing a prepolymer.

[0576] 5.00 parts by mass of a mixture of 2,5-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane [monomer a1 for optical materials] and 0.165 parts by mass of (±)-10-camphorsulfonic acid [organic acid, pKa value = 1.17] were mixed to prepare a mixed solution. The mixed solution was mixed with the mixture containing the prepolymer described above, and degassed at 400 Pa and 25° C. for 1 hour to obtain a mixture 1 containing the prepolymer.

[0577] Table 1 shows the viscosity and refractive index of the mixture 1 including the prepolymer.

[0578] 2.53 parts by mass of a mixture of 2,5-bis(isocyanatomethyl)-bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanatomethyl)-bicyclo-[2.2.1]-heptane [monomer a1 for optical materials], 20.43 parts by mass of pentaerythritol tetrakis(3-mercaptopropionate) [monomer b2 for optical materials], and 21.80 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] were mixed and stirred at 25° C. for 5 minutes to obtain a uniform solution. 0.02 parts by mass of 3,5-lutidine [basic polymerization catalyst, pKa value = 6.15] was added to the obtained uniform solution, and stirred at 40° C. for 3 hours to polymerize the monomers for optical materials. Then, deaeration was performed at 400 Pa and 25° C. for 1 hour to obtain a mixture 2 containing a prepolymer.

[0579] Table 1 shows the viscosity and refractive index of the mixture 2 containing the prepolymer.

[0580] Mixture 1 containing a prepolymer and mixture 2 containing a prepolymer were mixed at 20° C. to obtain a polymerizable composition. The obtained polymerizable composition was fed into a casting mold (ie, a mold) while being remixed in a static mixer.

[0581] The viscosity of the polymerizable composition when it was sent to the mold and cast (also referred to as casting viscosity) was adjusted to the value shown in Table 1.

[0582] When feeding the liquid, the polymerizable composition was filtered with a 1μm PTFE filter and injected into the mold cavity at a rate of 10g / second. The mold consisted of a 4-curved glass mold (upper mold) with a diameter of 78mm and a 4-curved glass mold (lower mold) with a diameter of 78mm and had a mold cavity for lens production.

[0583] The mold with the polymerizable composition injected was placed in a polymerization oven and heated from 20° C. to 120° C. over 10 hours. The molded body in a cured state of the polymerizable composition was released from the mold and annealed at 120° C. for 2 hours to obtain a molded body (lens).

[0584] [Example 2-2]

[0585] A molded product (lens) was obtained by the same method as in Example 2-1 except that the method for preparing the mixture 1 containing the prepolymer was changed as follows.

[0586] 0.1 parts by mass of an internal mold release agent for MR manufactured by Mitsui Chemicals [internal mold release agent], 1.5 parts by mass of Tinuvin 329 manufactured by BASF [ultraviolet absorber], and 48.07 parts by mass of a mixture of 2,5-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane and 2,6-bis(isocyanate methyl)-bicyclo-[2.2.1]-heptane [monomer a1 for optical materials] were mixed, stirred at 25° C. for 1 hour to completely dissolve the mixture, thereby obtaining a mixed solution. 3.47 parts by mass of pentaerythritol tetrakis(3-mercaptopropionate) [monomer b2 for optical materials] and 3.70 parts by mass of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane [monomer b1 for optical materials] were added to the mixed solution, and stirred at 25° C. for 5 minutes to obtain a uniform solution. 0.13 parts by mass of 3,5-lutidine (basic polymerization catalyst) was added to the obtained uniform solution, and the mixture was stirred at 40° C. for 3 hours to polymerize the monomer for an optical material, thereby obtaining a mixture containing a prepolymer.

[0587] 0.06 parts by mass of methanesulfonic acid [organic acid, pKa value = -2.6] was mixed with the above mixture containing the prepolymer, and degassed under the conditions of 400 Pa and 25° C. for 1 hour to obtain a mixture 1 containing the prepolymer.

[0588] Table 1 shows the viscosity and refractive index of the mixture 1 including the prepolymer.

[0589] [Comparative Example 2-1]

[0590] A molded body (lens) was obtained by the same method as in Example 2-1 except that (±)-10-camphorsulfonic acid was not used in the preparation of the mixture 1 containing the prepolymer.

[0591] [Comparative Example 2-2]

[0592] A molded body (lens) was obtained in the same manner as in Example 2-1, except that octanoic acid [organic acid, pKa value = 4.90] was used instead of (±)-10-camphorsulfonic acid in the preparation of the mixture 1 containing the prepolymer.

[0593] 〔evaluate〕

[0594] The following evaluations were performed on the polymerizable compositions and molded products obtained in each example or comparative example.

[0595] (Viscosity of mixture containing prepolymer)

[0596] The mixture containing the prepolymer was stirred at 25° C. and 60 rpm, and the viscosity was measured using a B-type viscometer (Spindle No. 2: Brookfield).

[0597] (Refractive index of mixture containing prepolymer)

[0598] The refractive index of the mixture containing the prepolymer at 20° C. was measured using a refractometer (RA-600: Kyoto Electronics Industry Co., Ltd.).

[0599] (Viscosity of polymerizable composition)

[0600] The polymerizable composition was stirred at 25° C. and 60 rpm, and the viscosity was measured using a B-type viscometer (Spindle No. 2: Brookfield).

[0601] (Slope of viscosity increase rate)

[0602] The horizontal axis (=X) is set to time (hr), and the vertical axis (=Y) is set to the viscosity (mPa·S) of the polymerizable composition. The time-dependent change in viscosity is plotted and fitted using the following formula. The value of b in the formula is taken as the slope of the viscosity increase rate. The viscosity of the polymerizable composition is measured using a B-type viscometer (Spindle No. 2: Brookfield) at 25°C and 30 rpm.

[0603] Y=a*exp(b*X)

[0604] The smaller the value of the viscosity increase rate slope is, the slower the viscosity increase rate is and the longer the pot life is.

[0605] (Applicable period)

[0606] The state of the polymerizable composition 30 minutes after the mixture 1 containing the prepolymer and the mixture 2 containing the prepolymer were mixed was evaluated according to the following criteria.

[0607] A: It can be cast 30 minutes after mixing

[0608] B: Viscosity increased 30 minutes after mixing and casting was impossible

[0609] (Wave tendons)

[0610] The molded body was projected with an ultra-high pressure mercury lamp (light source type OPM-252HEG: manufactured by Ushio Electric Co., Ltd.), and the transmitted image was observed visually and evaluated based on the following criteria.

[0611] A: No striae were observed. Specifically, striae having a length of 1.0 mm or more were not observed visually within and outside a radius of 15 mm from the center of the molded article.

[0612] B: Although ribs are observed, it is generally acceptable as a product. Specifically, although ribs of 1.0 mm or more in length are visually observed outside the range of 15 mm in radius from the center of the molded body, ribs of 1.0 mm or more in length are not visually observed within the range of 15 mm in radius from the center of the molded body, which is generally acceptable as a product.

[0613] C: Streaks were observed, which is unacceptable as a product. Specifically, striae of a length of 1.0 mm or more were visually observed within and outside a radius of 15 mm from the center of the molded article.

[0614] [Table 1]

[0615]

[0616] [Table 2]

[0617]

[0618] As shown in Tables 1 and 2, the polymerizable compositions of the Examples using a basic polymerization catalyst and an organic acid having a pKa value of less than 4, had a suppressed increase in viscosity and a good pot life compared to the polymerizable compositions of the Comparative Examples using no organic acid or using an organic acid having a pKa value of 4 or more. In addition, striae were not observed in the molded bodies (cured products) obtained using the polymerizable compositions of the Examples.

[0619] The entire disclosure of Japanese Patent Application Nos. 2023-135607 and 2023-135613 is incorporated into this specification by reference.

[0620] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard was specifically and individually described.

Claims

1. A polymerizable composition for an optical material, comprising two or more different monomers for an optical material, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, At least one of the two or more different monomers for optical materials is an isocyanate compound, The viscosity measured by a B-type viscometer at 25° C. and 60 rpm is 10 mPa·s to 1000 mPa·s.

2. The polymerizable composition for an optical material according to claim 1, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, The content of the basic polymerization catalyst is 0.010 to 0.50 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

3. The polymerizable composition for an optical material according to claim 1, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, The content of the basic polymerization catalyst is greater than 0.05 parts by mass and less than 2.0 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material. 4 . The polymerizable composition for an optical material according to claim 1 , further comprising a prepolymer which is a polymer of the two or more different monomers for an optical material and has a polymerizable functional group.

5. The polymerizable composition for an optical material according to claim 1, wherein The two or more different monomers for optical materials further include at least one active hydrogen compound selected from the group consisting of a polythiol compound having two or more mercapto groups, a hydroxythiol compound containing one or more mercapto groups and one or more hydroxyl groups, a polyol compound containing two or more hydroxyl groups, and an amine compound.

6. The polymerizable composition for an optical material according to claim 1, wherein At least one of the two or more different monomers for optical materials is an active hydrogen compound, and the total proportion of the isocyanate compound and the active hydrogen compound in the total of the two or more different monomers for optical materials is greater than 70% by mass.

7. The polymerizable composition for an optical material according to claim 1, wherein The molar number of the functional group of the organic acid having a pKa value less than 4 is less than the molar number of the functional group of the basic polymerization catalyst.

8. The polymerizable composition for an optical material according to claim 1, wherein The alkaline polymerization catalyst includes an alkaline polymerization catalyst having a pKa value of 4-8.

9. A polymerizable prepolymer composition for an optical material, comprising: a prepolymer which is a polymer of two or more different monomers for an optical material and has a polymerizable functional group; a basic polymerization catalyst; and an organic acid having a pKa value of less than 4, At least one of the two or more different monomers for optical materials is an isocyanate compound, The viscosity measured by a B-type viscometer at 25° C. and 60 rpm is 10 mPa·s to 2000 mPa·s.

10. The polymerizable prepolymer composition for optical material according to claim 9, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, The content of the basic polymerization catalyst is 0.002 to 1 part by mass based on 100 parts by mass of the total prepolymer.

11. The polymerizable prepolymer composition for optical material according to claim 9, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, The content of the basic polymerization catalyst is 0.1 to 4.0 parts by mass based on 100 parts by mass of the total prepolymer.

12. A cured product of the polymerizable composition for an optical material according to claim 1 or the polymerizable prepolymer composition for an optical material according to claim 9.

13. A method for producing an optical material, comprising: a preparation step of preparing a polymerizable composition for an optical material, wherein the polymerizable composition for an optical material comprises two or more different monomers for an optical material, a basic polymerization catalyst, and an organic acid having a pKa value of less than 4, At least one of the two or more different monomers for optical materials is an isocyanate compound; A casting step, adjusting the viscosity of the polymerizable composition for optical material to 10 mPa·s to 1000 mPa·s as measured by a B-type viscometer at 25° C. and 60 rpm, and casting the polymerizable composition for optical material into a mold; and The curing step is to cure the polymerizable composition for optical material by polymerizing the two or more different monomers for optical material in the polymerizable composition for optical material in the mold.

14. The method for producing an optical material according to claim 13, wherein: At least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, The content of the basic polymerization catalyst is 0.010 to 0.50 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

15. The method for producing an optical material according to claim 13, wherein: At least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, The content of the basic polymerization catalyst is greater than 0.05 parts by mass and less than 2.0 parts by mass based on 100 parts by mass of the total of the two or more different monomers for an optical material.

16. A method for producing an optical material, comprising: A preparation step of preparing two or more different monomers for optical materials and a basic polymerization catalyst; a prepolymerization step of mixing a part of the two or more different monomers for optical materials with at least a part of the basic polymerization catalyst, polymerizing at least a part of the two or more different monomers for optical materials to obtain a prepolymer, thereby obtaining a mixture containing the prepolymer; and an acid adding step, adding an organic acid having a pKa value of less than 4 to the mixture containing the prepolymer, At least one of the two or more different monomers for optical materials is an isocyanate compound.

17. The method for producing an optical material according to claim 16, wherein: At least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, The total amount of the two or more different monomers for optical materials is 100 parts by mass, and the amount of the basic polymerization catalyst is 0.010 to 0.50 parts by mass.

18. The method for producing an optical material according to claim 16, wherein: At least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, The total amount of the two or more different monomers for optical materials is 100 parts by mass, and the amount of the basic polymerization catalyst is greater than 0.05 parts by mass and is 2.0 parts by mass or less.

19. The method for manufacturing an optical material according to claim 16, further comprising: A step of producing a polymerizable composition for an optical material, comprising adding at least the remaining portion of the two or more different monomers for an optical material to a mixture containing the prepolymer, thereby obtaining a polymerizable composition for an optical material containing the two or more different monomers for an optical material, the prepolymer, the basic polymerization catalyst, and an organic acid having a pKa value of less than 4; and The curing step is to obtain an optical material which is a cured product of the polymerizable composition for optical material by curing the two or more different monomers for optical material in the polymerizable composition for optical material.

20. A cured product, which is a cured product of two or more different monomers for optical materials, at least one of the two or more different monomers for optical materials is an isocyanate compound, wherein there are no ribs with a length of 1.0 mm or more within a radius of 15 mm from the center of the cured product, The content of amines measured by gas chromatography-mass spectrometry was more than 0 mass %, and the content of organic acids having a pKa value of less than 4 measured by gas chromatography-mass spectrometry was more than 0 mass %.

21. The cured product according to claim 20, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having an aromatic ring, The content of the amine is 0.001 mass % to 0.50 mass %, and the content of the organic acid having a pKa value of less than 4 is 0.001 mass % to 1 mass %.

22. The cured product according to claim 20, wherein At least one of the two or more different monomers for optical materials is an isocyanate compound having no aromatic ring, The content of the amine is 0.03 mass % to 2.5 mass %, and the content of the organic acid having a pKa value of less than 4 is 0.01 mass % to 5 mass %.

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