Bifunctional (METH)acrylate-containing composition, and curable composition and cured product using same

Abstract

The present invention provides a bifunctional (meth)acrylate-containing composition capable of realizing a cured product having high transparency and high surface hardness and provides a curable composition and a cured product using the same. A bifunctional (meth)acrylate-containing composition according to the present invention contains at least a spiroglycol di(meth)acrylate represented by formula (1). The spiroglycol di(meth)acrylate represented by formula (1) is contained in an amount of 90.0-99.9 mass% relative to the total solids content of the bifunctional (meth)acrylate-containing composition, and the content ratio of spiroglycol mono(meth)acrylate represented by formula (2) is 0.1-10.0 mass% relative to the total solids content of the bifunctional (meth)acrylate-containing composition. (In formulae (1) and (2), R1 is a hydrogen atom or a methyl group.)

Description

Bifunctional (meth)acrylate-containing composition, and curable composition and cured product using the same

[0001] The present invention relates to a bifunctional (meth)acrylate-containing composition, and a curable composition and a cured product using the same.

[0002] (Meth)acrylate compounds having a spiroacetal skeleton in the molecule are excellent in mechanical strength, heat resistance, moisture resistance, transparency, etc., and are therefore useful compounds as intermediates or monomers for polymeric materials such as polyacrylates, and as raw materials for paints, inks, adhesives, lubricants, films, sheets, etc. They are also widely used in a wide range of fields, for example, optical components such as optical lenses, lighting components, electronic materials, automotive components, etc., as polymerizable compounds for thermosetting resin compositions, photocurable resin compositions, ionizing radiation-curable ink compositions, hologram compositions, etc., or as additives for lithium ion conductive electrolyte compositions.

[0003] Known methods for producing a (meth)acrylate compound having a spiroacetal skeleton in the molecule include, for example, a dehydration condensation method in which a dehydration esterification reaction is carried out between spiroglycol and (meth)acrylic acid (see Patent Documents 1 to 3), a transesterification method in which a dealcoholization esterification reaction is carried out between spiroglycol and ethyl acrylate (see Patent Document 4), and a transesterification method in which a dealcoholization esterification reaction is carried out between spiroglycol and methyl methacrylate (see Patent Document 5).

[0004] Japanese Patent Laid-Open No. 59-078193 Japanese Patent Laid-Open No. 60-142990 Japanese Patent Laid-Open No. 2005-343816 Japanese Patent Laid-Open No. 57-170933 Japanese Patent Laid-Open No. 2006-169374

[0005] In recent years, various high-performance materials have been required to have higher transparency and higher surface hardness in a wide range of fields, such as paints, inks, adhesives, optical components, lighting components, electronic materials, and automotive components, and the bifunctional (meth)acrylate-containing composition is also a useful compound as a raw material or additive for applications in the above fields. However, the effects of impurities have not been clarified. When commercially producing the bifunctional (meth)acrylate, the inclusion of impurities is unavoidable, so knowledge regarding the effects of the contained impurities on the product has been desired.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to clarify the influence of impurities in the bifunctional (meth)acrylate-containing composition, and to provide commercially and stably a bifunctional (meth)acrylate-containing composition that can realize a cured product having high transparency and high surface hardness, as well as a curable composition and a cured product using the same.

[0007] As a result of extensive research, the present inventors have newly designed and developed a spiroglycol di(meth)acrylate-containing composition in which the content of spiroglycol mono(meth)acrylate, a by-product of synthesis, is reduced to a threshold value or less, and have found that the above-mentioned problems can be solved by using this composition, thereby completing the present invention.

[0008] That is, the present invention provides various embodiments as shown below. [1] A bifunctional (meth)acrylate-containing composition, comprising at least a spiro glycol di(meth)acrylate represented by the following formula (1), the spiro glycol di(meth)acrylate represented by the formula (1) being contained in an amount of 90.0 mass % or more and 99.9 mass % or less based on the total solid content of the bifunctional (meth)acrylate-containing composition, and a spiro glycol mono(meth)acrylate represented by the following formula (2) being contained in an amount of 0.1 mass % or more and 10.0 mass % or less based on the total solid content of the bifunctional (meth)acrylate-containing composition. (In the formula (1), R １ are each independently a hydrogen atom or a methyl group. (In the formula (2), R１ is a hydrogen atom or a methyl group.) [2] The bifunctional (meth)acrylate-containing composition according to [1], wherein the spiro glycol di(meth)acrylate represented by formula (1) is contained in an amount of 98.2 mass% to 99.9 mass% based on the total solid content of the bifunctional (meth)acrylate-containing composition. [3] The bifunctional (meth)acrylate-containing composition according to [1] or [2], wherein the content of the spiro glycol mono(meth)acrylate represented by formula (2) is 0.1 mass% to 1.8 mass% based on the total solid content of the bifunctional (meth)acrylate-containing composition. [4] The bifunctional (meth)acrylate-containing composition according to any one of [1] to [3], further comprising a spiro glycol represented by formula (3): [5] The bifunctional (meth)acrylate-containing composition according to any one of [1] to [4], which is solid at 25°C. [6] The bifunctional (meth)acrylate-containing composition according to any one of [1] to [5], which is a transesterification reaction product of a spiroglycol and a (meth)acrylic acid ester. [7] The bifunctional (meth)acrylate-containing composition according to [6], wherein the (meth)acrylic acid ester is a (meth)acrylic acid alkyl ester. [8] A curable composition comprising the bifunctional (meth)acrylate-containing composition according to any one of [1] to [7]. [9] A cured product of the curable composition according to [8].

[0009] According to the present invention, it is possible to commercially and stably provide a bifunctional (meth)acrylate-containing composition that can produce a cured product having high transparency and high surface hardness, as well as a curable composition and a cured product using the same.

[0010] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Here, the embodiment described below is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In other words, the present invention can be carried out by making any modifications within the scope of the gist thereof. In this specification, for example, the notation of a numerical range such as "1 to 100" means a numerical range that includes both the lower limit value "1" and the upper limit value "100". The same applies to the notation of other numerical ranges.

[0011] In this specification, (meth)acrylic acid refers to either or both of acrylic acid and methacrylic acid, and (meth)acrylate refers to either or both of acrylate and methacrylate.

[0012] [Bifunctional (meth)acrylate-containing composition] The bifunctional (meth)acrylate-containing composition of the present embodiment is characterized in that it contains at least spiroglycol di(meth)acrylate (hereinafter, may be referred to as "SPGDA") represented by the following formula (1), the spiroglycol di(meth)acrylate represented by the following formula (1) is contained in an amount of 90.0 mass% to 99.9 mass% based on the total solid content of the bifunctional (meth)acrylate-containing composition, and the content of spiroglycol mono(meth)acrylate (hereinafter, may be referred to as "SPGMA") represented by the following formula (2) is 0.1 mass% to 10.0 mass% based on the total solid content of the bifunctional (meth)acrylate-containing composition.

[0013] (In the formula (1), R １ are each independently a hydrogen atom or a methyl group. (In the formula (2), R １ is a hydrogen atom or a methyl group.

[0014] In the bifunctional (meth)acrylate-containing composition of this embodiment, the content of spiroglycol di(meth)acrylate (SPGDA) represented by formula (1) is not particularly limited, but may be 90.0 mass% or more, 95.0 mass% or more, 97.0 mass% or more, 98.2 mass% or more, 98.5 mass% or more, or 99.0 mass% or more relative to the total solid content of the bifunctional (meth)acrylate-containing composition. The upper limit value is not particularly limited as long as it is 99.9 mass% or less, but may be 99.8 mass% or less, 99.7 mass% or less, 99.6 mass% or less, 99.5 mass% or less, or 99.4 mass% or less. The higher the content of SPGDA, the more likely it is that the resulting cured product, etc., will have high transparency and high surface hardness.

[0015] In the bifunctional (meth)acrylate-containing composition of this embodiment, the content of spiroglycol mono(meth)acrylate (SPGMA) represented by formula (2) may be 10.0% by mass or less relative to the total solid content of the bifunctional (meth)acrylate-containing composition, and is not particularly limited, but may be 8.0% by mass or less, 5.0% by mass or less, 3.0% by mass or less, 1.8% by mass or less, 1.5% by mass or less, or 1.0% by mass or less. The lower limit is not particularly limited, but may be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.4% by mass or more, or 0.5% by mass or more. The lower the content of SPGMA, the more likely it is that the resulting cured product will have high transparency and high surface hardness.

[0016] The bifunctional (meth)acrylate-containing composition of the present embodiment may further contain a spiro glycol (hereinafter, sometimes referred to as "SPG") represented by the following formula (3): For example, the bifunctional (meth)acrylate-containing composition of the present embodiment may be a transesterification reaction product of a spiro glycol and a (meth)acrylic acid ester, which will be described later. In this case, the bifunctional (meth)acrylate-containing composition of the present embodiment, which is the reaction product, may contain spiro glycol derived from a synthetic raw material.

[0017]

[0018] Here, when the bifunctional (meth)acrylate-containing composition of this embodiment contains a spiroglycol (SPG) represented by formula (3), a high SPG content results in a relatively reduced SPGDA content, so a low SPG content is preferable. Therefore, the SPG content in the bifunctional (meth)acrylate-containing composition of this embodiment is not particularly limited, but is preferably 1.8 mass% or less relative to the total solid content of the bifunctional (meth)acrylate-containing composition, and may also be 1.5 mass% or less, 1.2 mass% or less, 1.0 mass% or less, 0.5 mass% or less, 0.3 mass% or less, or 0.2 mass% or less. The lower limit is not particularly limited, but may be 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, or 0.1 mass% or more. The lower the SPG content, the more likely it is that the resulting cured product will have high transparency and high surface hardness. Therefore, the lower limit of the SPG content is set to 0.0 mass % as a guideline.

[0019] As described above, the bifunctional (meth)acrylate-containing composition of this embodiment may contain optional components SPGMA and SPG in addition to the essential component SPGDA, but may also contain other components. For example, the bifunctional (meth)acrylate-containing composition of this embodiment may be a transesterification reaction product of a spiroglycol and a (meth)acrylic acid ester, as described below. In this case, it may contain a (meth)acrylic acid ester derived from the synthetic raw materials, a catalyst, a polymerization inhibitor, by-product alcohols, etc. From the viewpoint of the transparency and surface hardness of the resulting cured product, etc., the content of these other components is not particularly limited, but is preferably less than 2.0 mass% in total relative to the total solid content of the bifunctional (meth)acrylate-containing composition, and may also be 1.0 mass% or less, 0.5 mass% or less, 0.1 mass% or less, or 0.05 mass% or less. The lower the content of these other components, the more likely it is that the resulting cured product, etc., will have high transparency and high surface hardness.

[0020] Here, the bifunctional (meth)acrylate-containing composition of the present embodiment contains SPGDA, which has a relatively high melting point, as a main component, and therefore can be essentially solid at 25°C.

[0021] The bifunctional (meth)acrylate-containing composition of this embodiment may be a transesterification reaction product of a spiroglycol and a (meth)acrylic acid ester. In the case of the transesterification reaction product, the (meth)acrylic acid ester may be a (meth)acrylic acid alkyl ester. As the (meth)acrylic acid alkyl ester, methyl (meth)acrylate and ethyl (meth)acrylate are preferred, and methyl methacrylate and methyl acrylate are more preferred. A preferred method for producing the bifunctional (meth)acrylate-containing composition of this embodiment will be described in detail below.

[0022] [Method for Producing Bifunctional (Meth)acrylate-Containing Composition] A preferred method for producing a bifunctional (meth)acrylate-containing composition of the present embodiment includes at least a step of carrying out a transesterification reaction of a spiroglycol and a (meth)acrylic acid ester in the presence of a polymerization inhibitor, wherein the polymerization inhibitor contains an N-oxyl compound and a polymerization inhibitor having a boiling point of 246° C. or lower. By using two polymerization inhibitors, an N-oxyl compound and a polymerization inhibitor having a boiling point of 246° C. or lower, in combination, it is possible to suppress polymerization of the raw material (meth)acrylic acid ester that would otherwise unintentionally occur during the transesterification reaction, and thereby it is possible to obtain the bifunctional (meth)acrylate-containing composition of the present embodiment as a high-purity reaction product.

[0023] The spiro glycol used as raw material 1 is 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane represented by the following formula.

[0024] The (meth)acrylic acid ester used as raw material 2 is preferably a (meth)acrylic acid alkyl ester from the viewpoint of carrying out a transesterification reaction by dealcoholization. Here, the alkyl moiety is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably an alkyl group having 1 to 2 carbon atoms. Specific examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an isobutyl group, an s-butyl group, a t-butyl group, and a cyclohexyl group. One (meth)acrylic acid ester may be used alone, or two or more types may be used in combination. As the (meth)acrylic acid alkyl ester, methyl (meth)acrylate and ethyl (meth)acrylate are more preferred, and methyl (meth)acrylate is most preferred.

[0025] In the method for producing a bifunctional (meth)acrylate-containing composition of this embodiment, it is essential to use a (meth)acrylic acid ester as raw material 2 in order to suppress the by-production of impurities due to the generated water. In other words, it is preferable that the transesterification reaction step is substantially free of (meth)acrylic acid. Here, "substantially free of (meth)acrylic acid" means that the content is less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 1,000 ppm, and even more preferably less than 500 ppm, relative to the total amount of spiroglycol and (meth)acrylic acid ester charged in the transesterification reaction step. It goes without saying that the preferred lower limit of the (meth)acrylic acid content is 0 ppm or below the measurement limit.

[0026] In a preferred production method of this embodiment, a bifunctional (meth)acrylate-containing composition containing spiroglycol di(meth)acrylate as a di(meth)acrylate compound is obtained by the transesterification reaction of the spiroglycol with a (meth)acrylic acid alkyl ester, and at this time, alcohol is by-produced by a dealcoholization reaction.

[0027] The transesterification reaction of the spiroglycol and the (meth)acrylic acid ester described above can be carried out according to a conventional method and is not particularly limited. Generally, it can be carried out in the presence of a catalyst at a reaction temperature of 65 to 120°C. It is preferable to carry out the reaction under conditions that allow the by-product alcohol to be distilled off. Therefore, the reaction temperature is preferably 65°C or higher, more preferably 70°C or higher, and preferably 110°C or lower, more preferably 100°C or lower. The reaction pressure in the transesterification reaction is not particularly limited, and may be normal pressure, reduced pressure, or increased pressure. The reaction time in the transesterification reaction is also not particularly limited, but is preferably 1 to 12 hours from the viewpoint of industrial production efficiency.

[0028] The transesterification reaction can be carried out by any of batch, semi-batch, and continuous methods. When carried out continuously, it is industrially advantageous to carry out the reaction by a continuous countercurrent contact method. In one example of a batch method, a reactor is charged with a spiroglycol, a (meth)acrylic acid ester, a polymerization inhibitor, and optionally a catalyst, and the mixture is stirred at a predetermined temperature while bubbling an oxygen-containing gas into the reaction solution as necessary. Thereafter, as the transesterification reaction progresses, a monohydric alcohol resulting from the dealcoholization reaction is by-produced. This monohydric alcohol may remain coexisting in the reaction system, but the progress of the transesterification reaction can be promoted by discharging the monohydric alcohol out of the reaction system.

[0029] During the transesterification reaction, it is preferable to introduce an oxygen-containing gas into the system from the viewpoint of suppressing polymerization of the (meth)acrylic acid ester. Specific examples of the oxygen-containing gas include, but are not limited to, air, a mixed gas of oxygen and nitrogen, and a mixed gas of air and nitrogen. Examples of a method for introducing the gas include a method of blowing the gas into the reaction product (so-called bubbling). The pressure in the system when the oxygen-containing gas is contacted may be normal pressure, reduced pressure, or increased pressure. The temperature in the system when the oxygen-containing gas is contacted is not particularly limited, but is preferably 65 to 110°C, more preferably 70 to 100°C.

[0030] The catalyst used in the transesterification reaction can be a transesterification catalyst known in the art, and is not particularly limited. For example, acid catalysts such as organic acids such as paratoluenesulfonic acid and methanesulfonic acid, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and cation exchange resins; alkali metal alkoxides, magnesium alkoxides, aluminum alkoxides, zirconium alkoxides such as zirconium tetrabutoxide, metal alkoxides such as titanium alkoxides such as tetramethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, and tetraisobutyl titanate; tetraphenoxy titanium; organic tin compounds such as dibutyltin oxide, dioctyltin oxide, dibutyltin dilaurate, dibutyltin dimethoxide, and dibutyltin diacetate; and anion exchange resins can be used. These may be used alone or in combination of two or more. However, in the production method of this embodiment, from the viewpoint of suppressing the generation of decomposition products of spiroglycol and by-products of the reaction between the spiroglycol and the (meth)acrylic acid ester and thereby obtaining a reaction product of even higher purity, it is preferable not to use a Brønsted acid catalyst, a phosphine-based compound, or the like. Therefore, the catalyst used in the production method of this embodiment is preferably a metal alkoxide, an organotin compound, or an anion exchange resin, more preferably a metal alkoxide. The amount of catalyst used can be appropriately set depending on the desired performance and is not particularly limited, but the molar ratio relative to 1 mole of the total amount of spiroglycol and (meth)acrylic acid ester charged in the transesterification reaction step is preferably 1:0.001 to 0.2, more preferably 1:0.005 to 0.1, and even more preferably 1:0.01 to 0.05.

[0031] In the transesterification reaction, the use of a solvent is not essential, and the transesterification reaction can be carried out in the absence of any solvent other than the (meth)acrylic acid ester. However, a solvent may be used if necessary. When a solvent is used, it is preferable to use a solvent other than water from the viewpoint of suppressing the generation of impurities. Specific examples of solvents other than water include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, and benzophenone; esters such as methyl benzoate and γ-butyrolactone; carbonate compounds such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and 1,2-butylene carbonate; sulfones such as sulfolane; sulfoxides such as dimethyl sulfoxide; n-hexane, cyclohexane, methylcyclohexane, n-heptane, n-octane, n-nonane, n-decane, benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and the like. Examples of suitable solvents include, but are not limited to, hydrocarbons such as benzene, amylbenzene, diamylbenzene, triamylbenzene, dodecylbenzene, didodecylbenzene, amyltoluene, isopropyltoluene, decalin, and tetralin; and ethers such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diamyl ether, diethyl acetal, dihexyl acetal, t-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, tetrahydropyran, trioxane, dioxane, anisole, diphenyl ether, dimethyl cellosolve, diglyme, triglyme, and tetraglyme. These may be used alone or in combination of two or more. Among these, ketones, ethers, and hydrocarbons are preferred from the viewpoint of removal efficiency under reflux conditions. When a solvent is used, the amount thereof is not particularly limited, but is preferably 1 to 70 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 10 to 30 parts by mass, relative to 100 parts by mass of the total amount of the spiro glycol and the (meth)acrylic acid ester charged in the transesterification reaction step.

[0032] In the transesterification reaction, the ratio of the spiro glycol to the (meth)acrylic acid ester is not particularly limited and can be appropriately set depending on the desired performance. From the viewpoint of reaction efficiency when the transesterification reaction is carried out under reflux conditions of the (meth)acrylic acid ester, the ratio of the spiro glycol to the (meth)acrylic acid ester is preferably equimolar to 15 times by mole, more preferably 5 times by mole or more, even more preferably 7 times by mole or more, more preferably 12 times by mole or less, and even more preferably 10 times by mole or less.

[0033] During the transesterification reaction, an N-oxyl compound and a polymerization inhibitor having a boiling point of 246°C or lower are used in combination as polymerization inhibitors. The reason why the combined use of two polymerization inhibitors in this manner can inhibit the polymerization of the raw material acrylic acid ester is unclear, but based on the findings of the present inventors, the reason is presumed as follows. In the production method of this embodiment, the transesterification reaction is mainly carried out in a state in which the spiroglycol is dissolved or dispersed in the liquid (meth)acrylic acid ester. Here, the N-oxyl compound, while present in the reaction liquid, inhibits the polymerization of the (meth)acrylic acid ester. Meanwhile, as the reaction liquid temperature increases, the (meth)acrylic acid ester gradually volatilizes from the reaction liquid, and a portion of it becomes present in the gas phase of the reaction vessel. Almost no N-oxyl compound is present in this gas phase, allowing the polymerization of the (meth)acrylic acid ester to proceed. Therefore, in the production method of this embodiment, a polymerization inhibitor having a boiling point of 246°C or lower is used in combination, causing the polymerization inhibitor to diffuse into the gas phase, thereby inhibiting the polymerization of the (meth)acrylic acid ester. However, the action is not limited to this presumption.

[0034] Here, examples of the N-oxyl compound include 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl, and 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine. Examples of N-oxyl compounds include, but are not limited to, 2,2,6,6-tetramethylpiperidine 1-oxyl, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-maleimido-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-phosphonoxy-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-maleimido-2,2,6,6-tetramethylpiperidine 1-oxyl, pyrrolidine 1-oxyl free radical compounds, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl, and 2,2,6,6-tetramethylpiperidine-1-oxyl. The N-oxyl compounds may be used alone or in combination of two or more.

[0035] As the polymerization inhibitor having a boiling point of 246°C or less, a phenolic compound and / or a quinone compound is preferred, and hydroquinone monomethyl ether (boiling point: 243°C) or p-benzoquinone (boiling point: up to 180°C / sublimable) is more preferred. By using such a polymerization inhibitor having a low boiling point or sublimable property, the polymerization inhibitor diffuses into the gas phase, thereby suppressing the polymerization of the (meth)acrylic acid ester. Note that the polymerization inhibitor having a boiling point of 246°C or less may be used alone or in combination of two or more.

[0036] The amounts of the N-oxyl compound and polymerization inhibitor having a boiling point of 246°C or less used can be appropriately set depending on the desired performance and are not particularly limited. From the viewpoint of inhibiting polymerization of the (meth)acrylic acid ester, the content ratio of the N-oxyl compound is preferably 1 ppm to 300 ppm, more preferably 3 ppm to 200 ppm, and even more preferably 5 ppm to 100 ppm, relative to the total amount of spiroglycol and (meth)acrylic acid ester in the step of performing the transesterification reaction. Furthermore, from the viewpoint of inhibiting polymerization of the (meth)acrylic acid ester, the content ratio of the polymerization inhibitor having a boiling point of 246°C or less is preferably 10 ppm to 3000 ppm, more preferably 15 ppm to 2500 ppm, and even more preferably 20 ppm to 2000 ppm, relative to the total amount of spiroglycol and (meth)acrylic acid ester in the step of performing the transesterification reaction.

[0037] The ratio of the N-oxyl compound to the polymerization inhibitor having a boiling point of 246°C or lower used is not particularly limited and can be appropriately set depending on the desired performance. From the viewpoint of inhibiting polymerization when a transesterification reaction is carried out under reflux conditions, the ratio of the N-oxyl compound to the polymerization inhibitor having a boiling point of 246°C or lower used is preferably 2:1 to 1:50, more preferably 1:1 to 1:40, and even more preferably 1:1.2 to 1:30, calculated as ppm.

[0038] In the production method of this embodiment, in addition to the N-oxyl compound and the polymerization inhibitor having a boiling point of 246° C. or less, other polymerization inhibitors may be used in combination. Examples of other polymerization inhibitors include, but are not limited to, organic polymerization inhibitors such as hydroquinone (boiling point: 282° C.), t-butylhydroquinone (boiling point: 288° C.), 2-t-butyl-4,6-dimethylphenol (boiling point: 249° C.), dibutylhydroxytoluene (boiling point: 265° C.), 2,6-di-t-butyl-4-methylphenol (boiling point: 265° C.), 2,4,6-tri-t-butylphenol (boiling point: 277° C.), 4-t-butylcatechol (boiling point: 285° C.), and phenothiazine (boiling point: 371° C.); inorganic polymerization inhibitors such as copper chloride, copper sulfate, and iron sulfate; and organic salt-based polymerization inhibitors such as copper butyldithiocarbamate and N-nitroso-N-phenylhydroxylamine aluminum salt. These other polymerization inhibitors may be used alone or in combination of two or more. The polymerization inhibitor may be added in a desired amount at once or in portions during the transesterification reaction. Alternatively, the polymerization inhibitor may be added continuously via a rectification column.

[0039] After the transesterification reaction, it is desirable to remove or deactivate the catalyst as necessary. Methods for removing or deactivating the catalyst include solid-liquid separation, hydrolysis by adding water, extraction with an aqueous solution containing an acid or alkali, adsorption, and the like. Alternatively, catalyst removal by solid-liquid separation after crystallization by adding a poor solvent, lowering the temperature, or vacuum concentration can be used. These operations may be appropriately selected depending on the type of raw material used, the type of catalyst, the type of (meth)acrylate obtained, the reaction conditions, and the like. These operations may be used alone or in combination of two or more. For example, in the case of a metal alkoxide, the catalyst may be deactivated by adding water.

[0040] After the above transesterification reaction, a di(meth)acrylic acid ester of spiroglycol (spiroglycol di(meth)acrylate) is obtained as the target di(meth)acrylate compound. At this time, a mono(meth)acrylic acid ester of spiroglycol (spiroglycol mono(meth)acrylate) may be produced as a by-product, but the content thereof is preferably small.

[0041] The production method of this embodiment allows for the production of high-purity spiro glycol di(meth)acrylate (a bifunctional (meth)acrylate-containing composition with a low SPGMA content) with good reproducibility at an industrial level. The conversion rate can be appropriately set depending on the desired performance and is not particularly limited. However, from the viewpoint of industrial productivity and the like, it is preferably 98.5 mass% or more, more preferably 99.0 mass% or more, even more preferably 99.5 mass% or more, and particularly preferably 99.8 mass% or more, based on the mass of the spiro glycol charged. The selectivity can be appropriately set depending on the desired performance and is not particularly limited. However, from the viewpoint of industrial productivity and the like, it is preferably 97.0 mass% or more, more preferably 97.5 mass% or more, even more preferably 98.0 mass% or more, and particularly preferably 98.5 mass% or more, based on the mass of the spiro glycol charged. The yield can be appropriately set depending on the desired performance and is not particularly limited. From the viewpoint of industrial productivity and the like, the yield is preferably 95.5% by mass or more, more preferably 96.5% by mass or more, even more preferably 97.5% by mass or more, particularly preferably 98.0% by mass or more, and most preferably 99.0% by mass or more.

[0042] The production method of this embodiment may include a step of purifying the product obtained after the transesterification reaction as described above. This purification step may be a step of removing unreacted raw materials and / or by-products. The purification step may be any method generally used as a purification method for acrylates. Specific examples include distillation purification, a reprecipitation method in which a bifunctional (meth)acrylate-containing composition is dissolved in a solvent and then cooled, a poor solvent is added, or the mixture is dropped into water, and a liquid-liquid extraction method. Liquid-liquid extraction conditions may include liquid-liquid extraction using acetone, toluene, or an aqueous sodium carbonate solution.

[0043] [Applications] The bifunctional (meth)acrylate-containing composition of this embodiment may be used alone or in combination with other resin raw materials or resins as needed. Examples of the other resin raw materials include compounds such as other (meth)acrylates, urethane (meth)acrylates, alcohols, thiols, and polyamic acids. Examples of the other resins include polycarbonates, polyesters, polyester carbonates, polyacrylates, polyurethanes, polyether polyols, epoxy resins, polyimides, silicone resins, alicyclic hydrocarbon resins, and hydrocarbon resins, as well as those whose terminals are modified with (meth)acrylic groups, vinyl groups, acids, esters, halogens, etc., but are not limited thereto. The method of use is not limited, and the composition may be added either before or after the synthesis of the resin raw materials or resins to be used in combination. Specifically, the composition can be mixed with the resin raw materials or resins to be used in combination to prepare a resin composition. The resin composition may be formed by heating and melting, or curing may be initiated at this stage. A cured product can be obtained by applying the resulting resin composition to a glass or film surface and then photocuring. The obtained resin composition may be dissolved in various solvents to form a solution, which may be applied to the surface of glass or a film, followed by drying and photocuring. Alternatively, other cured resins may be immersed in the bifunctional (meth)acrylate-containing composition of this embodiment to impregnate them. The composition may also be used in combination with various photoinitiators, inorganic substances such as oxide particles, semiconductor particles, pigments, viscosity modifiers such as rosin, or surfactants. Alternatively, the composition may be added to other resins as a crosslinker or compatibilizer.

[0044] A resin composition containing the bifunctional (meth)acrylate-containing composition of this embodiment is useful as a raw material for paints, adhesives, films, sheets, and the like, and can be used for applications such as automobile parts, construction parts, vehicle windows, various parts (including optical members) for televisions, video cameras, audio players, smartphones, displays, computers, copiers, and the like, furniture parts such as lighting covers, blinds, and interior fixtures, optical elements such as light diffusion plates, light guide plates (light guides), optical lenses, optical molded bodies (including substrates for optical discs, etc.), light diffusing films, optical films, optical filters, protective films, transparent adhesive sheets, coating agents, LED / organic EL sealants, insulating materials between layers of electronic components, resist inks such as solder resists for printed circuit boards, and photocurable resin compositions for three-dimensional modeling.

[0045] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited thereto. In other words, the materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the spirit of the present invention. Furthermore, the values ​​of various manufacturing conditions and evaluation results in the following examples represent preferred upper or lower limits in the embodiments of the present invention, and preferred numerical ranges may be defined by combining the above-mentioned upper or lower limits with the values ​​of the following examples or values ​​between the examples. In the following, unless otherwise specified, "%" means "% by mass" and "ppm" means "ppm by mass."

[0046] The content ratios of SPGDA, SPGMA, and SPG in the bifunctional (meth)acrylate-containing composition of this embodiment can be identified by gas chromatography (Shimadzu Corporation: GC-2010PLUS) shown below. Detailed GC conditions are shown below. <GC conditions> Column: DB-1, film thickness 1.5 μm, length 30 m, inner diameter 0.53 mm Injection port temperature: 280°C Injection mode: Split Gas control: Pressure Pressure: 35.7 kPa Linear velocity: 48.0 cm / s Oven temperature program: Initial 65°C 65°C 5 minute hold 3°C / min 85°C 10 minute hold 5°C / min 250°C 25 minute hold Carrier gas: He

[0047] Example 1 Step 1 A 1 L flask equipped with a stirrer, a thermometer, a gas inlet tube, and a rectification column (a timer-controlled reflux head with a condenser attached to the end of a packed column) was charged with 152.4 g (0.50 mol) of SPG (spiroglycol), 560.0 g (6.50 mol) of MA (methyl acrylate), 3.45 g (12.1 mmol) of TTIP (tetraisopropyl orthotitanate) as a catalyst, 0.07 g (95.9 ppm with respect to the total amount of SPG and MA charged) of MEHQ (4-methoxyphenol) as a polymerization inhibitor, and 0.05 g (67.9 ppm with respect to the total amount of SPG and MA charged) of 4H-TEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl), and an oxygen-containing gas (8 vol% oxygen, 92 vol% nitrogen) was bubbled into the liquid at 40 mL / min. The transesterification reaction was carried out while stirring at a reaction temperature of 80°C, and a mixture of the by-product MeOH and the raw material MA was distilled from the reaction system through a rectification column. MA was added to the reaction solution in an amount equal to the weight of the distillate. Heating was stopped 6 hours after the start of stirring. After the reaction temperature was cooled to 65°C or less, H ２ 2.78 g (0.15 mol) of O was added to deactivate the TTIP catalyst.

[0048] Second step: The reaction product liquid obtained in the first step (reaction step) is decompressed while maintaining the temperature at 65°C, and ２O and MA were distilled off. 615 g of acetone was added to the remaining reaction product, heated to 54 ° C. to dissolve the acrylate product, and then filtered using a filter aid (Radiolite #800). By ice-cooling the filtrate, SPGDA (spiroglycol diacrylate) and the like were precipitated, and crystals (solid) of a bifunctional (meth)acrylate-containing composition containing SPGDA were recovered. The obtained crystals were washed with an appropriate amount of acetone and then dried at 30 ° C. for 3 hours using a vacuum dryer to obtain crystals.

[0049] [Example 2] First step A 1 L flask equipped with a stirrer, a thermometer, a gas inlet tube, and a rectification column (a timer-controlled reflux head with a condenser attached to the end of a packed column) was charged with 125.0 g (0.41 mol) of SPG (spiroglycol), 601.5 g (6.99 mol) of MA (methyl acrylate), 3.84 g (13.5 mmol) of TTIP (tetraisopropyl orthotitanate) as a catalyst, 0.08 g (109.9 ppm with respect to the total amount of SPG and MA charged) of MEHQ (4-methoxyphenol) as a polymerization inhibitor, and 0.06 g (82.7 ppm with respect to the total amount of SPG and MA charged) of 4H-TEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl), and an oxygen-containing gas (8 vol% oxygen, 92 vol% nitrogen) was bubbled into the liquid at 40 mL / min. The transesterification reaction was carried out with stirring at a reaction temperature of 80°C, and a mixture of the by-product MeOH and the raw material MA was distilled from the reaction system through a rectification column. MA was added to the reaction solution in an amount equal to the weight of the distillate. Heating was stopped 4 hours after the start of stirring. After the reaction temperature was cooled to 65°C or less, H ２ 10.45 g (0.58 mol) of O was added to deactivate the TTIP catalyst.

[0050] Second step: The reaction product liquid obtained in the first step (reaction step) is decompressed while maintaining the temperature at 65°C, and ２O and MA were distilled off. 526 g of acetone was added to the remaining reaction product, heated to 54 ° C. to dissolve the acrylate product, and then filtered using a filter aid (Radiolite #800). By ice-cooling the filtrate, SPGDA (spiroglycol diacrylate) and the like were precipitated, and crystals (solid) of a bifunctional (meth)acrylate-containing composition containing SPGDA were recovered. The obtained crystals were washed with an appropriate amount of acetone and then dried at 30 ° C. for 3 hours using a vacuum dryer to obtain crystals.

[0051] [Comparative Example 1] First step A 300 ml flask equipped with a stirrer, a thermometer, a gas inlet tube, and a Dean-Stark tube (connected to a condenser) was charged with 30.6 g (0.10 mol) of SPG (spiroglycol), 18.5 g (0.26 mol) of acrylic acid, 72.0 g (0.78 mol) of toluene as a solvent, 0.51 g (5.3 mmol) of MSA (methanesulfonic acid) as a catalyst, 0.13 g of MEHQ (4-methoxyphenol) as a polymerization inhibitor (2716.2 ppm with respect to the total amount of SPG and acrylic acid charged), and 0.01 g of 4H-TEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl) (273.2 ppm with respect to the total amount of SPG and acrylic acid charged), and an oxygen-containing gas (5 vol% oxygen, 95 vol% nitrogen) was bubbled into the liquid at 10 mL / min. The dehydration esterification reaction was carried out while stirring the reaction solution at a temperature of 80°C, and the produced water was distilled off from the reaction system via a Dean-Stark tube by evacuating at 50 kPa abs. After about 8 hours, heating of the reaction solution was stopped. After returning to normal pressure, the reaction solution temperature was lowered to 70°C, a 48% aqueous NaOH solution was added, and the mixture was stirred for 30 minutes.

[0052] Second step: The reaction product liquid obtained in the first step (reaction step) is decompressed while maintaining the temperature at 70°C, and ２O, acrylic acid, and toluene were distilled off. 126 g of acetone was added to the remaining reaction product, heated to 54 ° C. to dissolve the acrylate product, and then filtered using a filter aid (Radiolite #800). By cooling the filtrate to room temperature, SPGDA (spiroglycol diacrylate) and the like were precipitated, and crystals (solid) of a bifunctional (meth)acrylate-containing composition containing SPGDA were recovered. The obtained crystals were washed with an appropriate amount of acetone and then dried at 30 ° C. for 3 hours using a vacuum dryer to obtain crystals.

[0053] [Preparation of Cured Film for Evaluation] A silicone-treated PET film (50 μm thick) was placed on a glass plate (length 150 mm, width 150 mm, thickness 3 mm) heated to 150°C on a hot plate and fixed in place using heat-resistant polyimide tape. Separately, a photopolymerization initiator, 1-hydroxycyclohexyl phenyl ketone, was added to the bifunctional (meth)acrylate-containing composition obtained in the examples in an amount of 2% relative to the bifunctional (meth)acrylate-containing composition, and the mixture was then heated and stirred to homogenize. After placing 0.5 mm-thick silicone sheets as spacers on the left and right of the dropped composition, the prepared mixture was dropped onto the PET film, and after dropping, the dropped composition was sandwiched between the PET films. The sandwiched composition was then irradiated with a desktop UV irradiation device "ESC-1511U" manufactured by Eye Graphics Co., Ltd. at an irradiation intensity of 604 mW / cm. ２ , cumulative light intensity 737 mJ / cm ２ A cured film for evaluation having a length of 30 mm, a width of 30 mm and a thickness of about 0.5 mm was prepared.

[0054] [Total Light Transmittance] After UV curing, the evaluation film was measured for haze using a haze meter "COH 7700" manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7361-1.

[0055] [Pencil Hardness] After UV curing, the pencil hardness of the evaluation film was measured according to the test method of JIS K5600-5-4, and the hardness at which no scratches were found on the surface was recorded.

[0056] Table 1 shows the evaluation results.

Claims

1. A bifunctional (meth)acrylate-containing composition comprising at least a spiro glycol di(meth)acrylate represented by the following formula (1), the spiro glycol di(meth)acrylate represented by the formula (1) being contained in an amount of 90.0% by mass or more and 99.9% by mass or less based on the total solid content of the bifunctional (meth)acrylate-containing composition, and the content of a spiro glycol mono(meth)acrylate represented by the following formula (2) being 0.1% by mass or more and 10.0% by mass or less based on the total solid content of the bifunctional (meth)acrylate-containing composition. (In the above formula (1), R １ are each independently a hydrogen atom or a methyl group. (In the above formula (2), R １ is a hydrogen atom or a methyl group.

2. The bifunctional (meth)acrylate-containing composition according to claim 1, wherein the spiro glycol di(meth)acrylate represented by the formula (1) is contained in an amount of 98.2 mass% or more and 99.9 mass% or less based on the total solid content of the bifunctional (meth)acrylate-containing composition.

3. The bifunctional (meth)acrylate-containing composition according to claim 1, wherein the content of the spiro glycol mono(meth)acrylate represented by the formula (2) is 0.1 mass% or more and 1.8 mass% or less with respect to the total solid content of the bifunctional (meth)acrylate-containing composition.

4. The bifunctional (meth)acrylate-containing composition according to claim 1, further comprising a spiro glycol represented by the following formula (3), wherein the content of the spiro glycol represented by the formula (3) is 1.8 mass% or less based on the total solid content of the bifunctional (meth)acrylate-containing composition:

5. The difunctional (meth)acrylate-containing composition according to claim 1, which is solid at 25°C.

6. The difunctional (meth)acrylate-containing composition according to claim 1, which is an ester exchange reaction product of a spiroglycol and a (meth)acrylic acid ester.

7. The bifunctional (meth)acrylate-containing composition according to claim 6, wherein the (meth)acrylic acid ester is an alkyl (meth)acrylic acid ester.

8. A curable composition comprising the difunctional (meth)acrylate-containing composition of claim 1.

9. A cured product of the curable composition according to claim 8.

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