JP2019119715A - Production process for multifunctional (meth)acrylate and network polymer - Google Patents

Abstract

To provide a production process for easily and surely obtaining polyfunctional (meth)acrylate with high yield using inositol as a raw material.SOLUTION: By reacting inositol and (meth)acryloyl chloride in the presence of an esterification catalyst in a solvent, a multifunctional (meth)acrylate in which (meth)acryloyl groups are ester-bonded to each of a plurality of hydroxyl group positions of inositol is synthesized. The number of (meth)acryloyl groups in the synthesized product may be any of 2 to 6.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing inositol-based polyfunctional (meth) acrylate, and a method for producing a network polymer using this polyfunctional (meth) acrylate. Here, (meth) acrylate is a generic name of acrylate and methacrylate, and (meth) acryloyl described later is also a generic name of acryloyl and methacryloyl.

  (Meth) acrylates are polymerized and cured by heating and irradiation with active energy rays such as ultraviolet rays and electron beams, and thus various types of moldings such as binders for paints and inks, adhesives, sealing agents, films, optical lenses, etc. It is widely used as a raw material monomer and a crosslinking component. In particular, multifunctional (meth) acrylates having a plurality of (meth) acryloyl groups have high utility as hard coating materials because they form cured products having high hardness and excellent abrasion resistance and transparency.

  Such polyfunctional (meth) acrylates are generally synthesized by esterification reaction or transesterification reaction of polyhydric alcohol and monofunctional (meth) acrylate, and equivalent to the valence of polyhydric alcohol used Although the ratio determines the number of functional groups, that is, the number of (meth) acryloyl groups which are radically polymerizable groups, a network polymer having high crosslinking density and high hardness can be formed as the number of functional groups increases. Conventionally, a large number of tetrafunctional or higher polyfunctional (meth) acrylates are known, but usually, linear aliphatic polyhydric alcohols or (meth) acrylic esters of di-trimers thereof, For example, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol octa A (meth) acrylate etc. are used abundantly (patent documents 1-4).

JP, 2013-237845, A (paragraph 0025) JP, 2015-113414, A (paragraph 0037) International Publication WO2015 / 159611 (paragraph 0003) JP, 2015-187241, A (paragraph 0009)

  In the chain-like aliphatic polyhydric alcohol or the di-trimeric (meth) acrylic ester thereof, which is conventionally used, the homopolymer thereof and the copolymer with other radically polymerizable monomers have a high crosslinking density High-hardness network polymer, but due to structural limitations of crosslink density, it can not cope with cases where higher hardness or mechanical strength is required as a film or a molded product, and it can not be used for heat resistance, hard coating materials, etc. In terms of adhesion to the surface of inorganic materials, it was not sufficient.

  In view of the above-mentioned circumstances, the inventors of the present invention have intensively studied to obtain a polyfunctional (meth) acrylate capable of forming a network polymer with high crosslinking density and high hardness. We focused on inositol, which is a formula hexahydric alcohol. This inositol is one in which one hydroxyl group is bonded to each carbon atom of the six-membered ring of aliphatic hydrocarbon, but among nine stereoisomers different in the configuration of the hydroxyl group, representative myoinositol Several species including (myoinositol, meso-inositol) are included in natural materials such as grains, fruits and beans. And, in addition to being stable to dilute acid and alkali, these natural materials inositol are opposite to each other in the coordination direction of the six hydroxyl groups with respect to the ring at 4: 2 or 3: 3. Thus, for example, in a hexa (meth) acrylate in which a (meth) acryloyl group is ester-bonded to the position of each hydroxyl group, six (meth) acryloyl groups extend from different positions of the hydrocarbon ring to both sides with respect to the ring surface And the monomers themselves are in a three-dimensional steric form, and the functional groups are present in extremely close proximity, and their homopolymerization and copolymerization with other radically polymerizable monomers result in extremely high directivity. It is expected to form a cross-linked structure with a high density and to be a highly functional network polymer with very high hardness and excellent mechanical strength and heat resistance.

  However, inositol has low compatibility with various organic compounds and low solubility in organic compounds, and it is lower than conventionally used general-purpose polyhydric alcohols such as chain aliphatic polyhydric alcohols and their di- to 3-mers. Since the reactivity is extremely poor, it is difficult to efficiently add functional groups, and in the absence of a solvent, it does not react even if a reactant and catalyst are added, and even when a solvent is used, most of the reactions are common in general solvents. There is a disadvantage that it does not occur or the yield is extremely low.

  In spite of the above-mentioned circumstances, as a result of repeated extensive research on polyfunctional (meth) acrylates starting from inositol, the present invention makes it possible to easily and reliably obtain high yields of the polyfunctional (meth) acrylates. The present inventors have investigated the production method to be obtained and the production method of the network polymer using the obtained monomer. In addition, although the patent documents (for example, patent document 3) which contained inositol in many illustrated as a polyhydric-alcohol component used for the synthesis | combination of polyfunctional (meth) acrylate are scattered, in any case, inositol was used. No specific synthetic method is disclosed for multifunctional (meth) acrylates and no examples of use as monomers for polymer synthesis are shown.

  The method for producing a polyfunctional (meth) acrylate according to claim 1 of the present invention is characterized in that inositol and (meth) acryloyl chloride are reacted in a solvent in the presence of an esterification catalyst.

  In the present invention, as a preferred embodiment of the method for producing a polyfunctional (meth) acrylate according to claim 1, in claim 2, the solvent is at least one selected from a nitrile solvent and a halogen solvent, In the third embodiment, the solvent is acetonitrile. In the fourth embodiment, the basic compound is added to the reaction system, and the hydrogen chloride by-produced in the reaction is neutralized. In the fifth embodiment, the esterification catalyst is N, N-dimethyl-. A configuration which is 4-aminopyridine, and a configuration in which the polyfunctional (meth) acrylate is hexa (meth) acrylate are defined in claim 6, respectively.

  On the other hand, in the method for producing a network polymer according to claim 7 of the present invention, a single monomer of polyfunctional (meth) acrylate obtained by the production method according to any one of claims 1 to 6, or other radically polymerizable It is characterized by radical polymerization of a mixed monomer with a monomer.

  Furthermore, according to the present invention, as a preferred embodiment of the method for producing a network polymer according to claim 7, in claim 8, a single monomer of the polyfunctional (meth) acrylate or a mixed monomer with another radically polymerizable monomer is A configuration in which radical polymerization is performed by active energy ray irradiation in the presence of a polymerization initiator, and a configuration in which the other radical polymerizable monomer is a (meth) acrylic acid alkyl ester are defined in claim 9 respectively.

  According to the method for producing a polyfunctional (meth) acrylate of the present invention, using inositol as a polyhydric alcohol component, a (meth) acrylate having 2 to 6 (meth) acryloyl groups can be easily and surely obtained it can. Then, in the obtained polyfunctional (meth) acrylate, (meth) acryloyl groups are respectively ester-bonded to the positions of the plurality of hydroxyl groups of inositol, and the plurality of (meth) acryloyl groups are stretched on both sides with respect to the ring face It is a three-dimensional steric form of molecules coordinated so as to emit. Therefore, as in the method for producing a network polymer of the present invention, the directionality can be obtained by radically polymerizing the above-obtained polyfunctional (meth) acrylate as a single monomer or copolymerizing with other radically polymerizable monomers. A highly functional network polymer having high density and high mechanical strength and heat resistance having a high density crosslinked structure is obtained. In addition, such network polymers have been found to be excellent in adhesion to the surface of inorganic materials such as glass and ceramic, for example, hard coatings that protect the surface of optical glass such as displays and lenses in various electronic devices. It has high suitability as a material etc.

  In particular, hexafunctional (meth) acrylates, that is, inositol hexa (meth) acrylates, can form a network polymer of very high hardness, high mechanical strength and high heat resistance with a higher density crosslinked structure. In addition, if a polyfunctional (meth) acrylate leaving a part of hydroxyl groups of inositol is synthesized by reacting (meth) acryloyl chloride less than equivalent to inositol, various chemical modifications using the hydroxyl groups are Since this becomes possible, there is also an advantage that the chemical modification can impart various physical properties and functions according to the application.

  Therefore, in the method for producing a polyfunctional (meth) acrylate of the present invention, a high yield can be obtained by using a nitrile solvent and a halogen solvent as a reaction solvent. In particular, when acetonitrile is used as the solvent, the polyfunctional (meth) acrylate can be produced in high yield without causing problems in working environment such as carcinogenicity due to solvent volatilization. The reaction efficiency can be enhanced by adding a basic compound to the reaction system to neutralize hydrogen chloride by-produced in the reaction or by using N, N-dimethyl-4-aminopyridine as an esterification catalyst. .

  On the other hand, in the method for producing a network polymer according to the present invention, the monomer of the polyfunctional (meth) acrylate alone or a mixed monomer of other radical polymerizable monomers is radicalized by active energy ray irradiation in the presence of a photopolymerization initiator. Since polymerization can be efficiently cured in a short time, it is particularly suitable for forming a hard coat layer. Furthermore, when (meth) acrylic acid alkyl ester is used as another radically polymerizable monomer, the heat resistance of the copolymer formed can be controlled by the use ratio of both monomers, and thereby the thermal characteristics according to the application of the polymer can be obtained. It can be set.

It is a < ¹ > H-NMR spectrum figure of the hexamethacrylate obtained by the manufacturing method of this invention. It is a ¹³ C-NMR spectrum figure of the same hexamethacrylate. It is a solid-state NMR spectrum of the homopolymer which superposed | polymerized the hexamethacrylate. It is IR spectrum of the monomer and homopolymer of the same hexamethacrylate.

  In the method for producing a polyfunctional (meth) acrylate of the present invention, as described above, a plurality of hydroxyl groups of inositol are reacted by reacting inositol and (meth) acryloyl chloride in a solvent in the presence of an esterification catalyst. Synthesized polyfunctional (meth) acrylates each having a (meth) acryloyl group esterified at the position of Although the number of (meth) acryloyl groups in the compound may be any of 2 to 6, for example, the synthesis of inositol hexa (meth) acrylate using myoinositol is represented by the following chemical formula (I). HM is an abbreviation of hexamethacrylate.

(In the formula, n is an integer of 6 or more. Of the 6 OH groups of myoinositol, 4 in which the bond is indicated by a solid line and 2 in a broken line with respect to the hydrocarbon ring have opposite coordination directions. is there.

  The inositol used in the present invention is not particularly limited, but myo-inositol, D-inositol, L-inositol and silit are naturally present among 9 kinds of stereoisomers due to the difference in configuration of six hydroxyl groups. And it is suitable as being stable to dilute acid and alkali. In particular, myo-inositol is abundantly contained in grains and beans as phytin, and is easily obtained by hydrolysis of phytic acid (a hexaphosphate of myo-inositol) obtained by desalting (removing such as Mg, Ca etc.) the phytin. It is recommended from the viewpoint of material cost. In the myo-inositol, the coordination direction of the six hydroxyl groups is opposite to 4: 2 with respect to the ring, and in the other three types, the coordination direction is opposite to 3: 3.

  The blending ratio of inositol and (meth) acryloyl chloride may be set according to the number of functional groups of the desired polyfunctional (meth) acrylate, that is, the number of (meth) acryloyl groups. For example, in order to obtain hexa (meth) acrylate, reactivity is higher than the equivalent of (meth) acryloyl chloride with respect to inositol, that is, 6 mol or more of monovalent chloride (meth) acryloyl per 1 mol of hexavalent inositol From the aspect, it is preferable that the amount be 8 moles or more. Moreover, what is necessary is just to increase / decrease the compounding quantity of chloride (meth) acryloyl with respect to an inositol by less than an equivalent according to the degree of the functional group number, when obtaining 2-5 functional (meth) acrylate.

  As an esterification catalyst used for the above synthesis, N, N-dimethyl-4-aminopyridine (hereinafter abbreviated as DMAP), 1,8-diazabicyclo [5.4.0] undec-7-ene, 1, 5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] octane, 1-azabicyclo [2.2.2] octane, imidazole, amidine and the like In particular, DMAP is preferable in view of high catalytic activity. The amount of the esterification catalyst used is preferably about 0.01 to 1.0 mol with respect to 1 mol of inositol.

  As a solvent for the synthesis reaction, nitrile solvents and halogen solvents are suitable. Examples of the nitrile solvents include acetonitrile, propionitrile, butyronitrile, benzonitrile and the like, but acetonitrile is recommended from the viewpoint of ease of distillation after reaction and safety. Further, as the halogen-based solvent, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and the like can be mentioned. However, it is desirable not to use dichloromethane because high carcinogenic results have been obtained, but carcinogenic problems have been pointed out.

  Incidentally, as solvents for general esterification reaction, in addition to those listed above, hydrocarbon solvents such as hexane and toluene, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, ethyl acetate and acetic acid Ester solvents such as ethyl, ketone solvents such as acetone and ethyl methyl ketone, amide solvents such as dimethylformamide and dimethylacetamide, and metal halides such as lithium chloride dissolved in the amide solvents However, it has been found that the synthesis reaction does not occur in these solvents, or the yield is very low even if they occur.

  In addition, since hydrogen chloride (HCl) is produced | generated with esterification in the said synthetic reaction, in order to neutralize this and to accelerate reaction, it is preferable to add a basic compound to a reaction system. As such basic compounds, inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and derivatives thereof, imidazoles, imidazolines, triazoles, thiazoles, pyrroles, pyridines, pyrimidines And piperazines, piperidines, guanidines, etc., but triethylamine, trimethylamine, triethanolamine, N, N-dimethylpropylamine, N-ethyl-N-methylbutylamine, N-ethyldiisopropylamine, etc. Preferred are primary amines. And, in particular, triethylamine is recommended in view of its high solubility in acetonitrile suitable as a solvent and easy to distill off after the reaction. The amount of such a basic compound used is preferably about 1 to 10 moles relative to 1 mole of chloride (meth) acryloyl.

  Furthermore, in the above synthesis reaction, it is desirable to add a polymerization inhibitor to the reaction system in order to prevent thermal polymerization of (meth) acryloyl chloride. As this polymerization inhibitor, hydroquinone, t-butylhydroquinone, p-benzoquinone, 2,5-dihydroxy-p-quinone, p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 3-hydroxythiophenol Α-nitroso-β-naphthol, p-phenylenediamine, phenyl-β-naphthylamine, copper salts and the like. And it is good for the usage-amount of such a polymerization inhibitor to be about 0.001-0.1 mol with respect to 1 mol of chloride (meth) acryloyl.

  In the above synthesis reaction, the reaction solution may be stirred for 1 to 72 hours at a temperature of about −20 to 50 ° C. in an inert gas atmosphere such as argon. Then, the generated polyfunctional (meth) acrylate is extracted with a solvent by adding brine to the reaction solution, the organic layer is dehydrated with sodium sulfate or the like, filtered, preferably, a polymerization inhibitor is added and concentrated, and recrystallization The reaction product is obtained as white needles.

  The polyfunctional (meth) acrylate thus obtained is a molecule in which (meth) acryloyl groups are ester-bonded at the positions of a plurality of hydroxyl groups of inositol used as a raw material, as exemplified by hexamethacrylate as a representative in the chemical formula (1). It has a structure. In the case of hexa (meth) acrylate, due to the configuration of hydroxyl group of inositol, in the case of using myoinositol, 4 and 2 of (meth) acryloyl groups are on the opposite side to the ring face of the hydrocarbon ring Coordinated so as to overhang, and in the case of using D-inositol, L-inositol and silitate, three of each of (meth) acryloyl groups are coordinated so as to overhang on the opposite side, and all of them are third-order It becomes an original three-dimensional form.

  Therefore, homopolymers obtained by polymerizing these hexa (meth) acrylates alone as monomers, and copolymers obtained by copolymerizing with other radically polymerizable monomers have an extremely high-density crosslinked structure without directivity. It is a highly functional network polymer with very high hardness, excellent mechanical strength and heat resistance. In addition, such network polymers have been found to be excellent in adhesion to the surface of inorganic materials such as glass and ceramic, for example, hard coatings that protect the surface of optical glass such as displays and lenses in various electronic devices. It has high suitability as a material etc. On the other hand, if a 2- to 5-functional (meth) acrylate leaving some of the hydroxyl groups of inositol is synthesized, various chemical modifications using that hydroxyl group become possible, so that various physical properties according to the application by the chemical modification. It has the advantage of being able to In addition, such a polyfunctional (meth) acrylate is used as a reactive binder component which is cross-linked and cured by heat or light in a paint, together with various other additives such as monomers, polymers, fillers, aggregates and colorants. You may mix | blend.

  The method for producing a network polymer according to the present invention comprises radically polymerizing a single monomer of the polyfunctional (meth) acrylate synthesized from inositol and chloride (meth) acryloyl described above, or a mixed monomer with another radically polymerizable monomer. It is. The synthesis of a homopolymer by radical polymerization of a single monomer of hexamethacrylate is shown by the following chemical formula (II) as a representative of the method of preparation. NP on the right side is an abbreviation for network polymer.

  Thus, for the synthesis of the above-mentioned network polymer, there is a solution polymerization method in which a monomer solution is heated and reacted in the presence of a radical polymerization initiator in an inert gas atmosphere such as argon, and in the presence of a photopolymerization initiator There is a photopolymerization method in which a monomer solution is reacted by irradiating active energy rays such as ultraviolet rays and electron beams. In the latter photopolymerization method, a monomer solution is coated on the surface of a substrate such as glass, ceramic, metal or the like in the air, and the coating film can be efficiently cured in a short time by irradiating active energy rays. It is suitable for formation of a layer.

  As a radical polymerization initiator to be used in the former solution polymerization method, 2,2'-azobis (isobutyronitrile) (hereinafter abbreviated as AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile) Azo compounds such as 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, and di-t-butyl Peroxides, peroxides such as t-butyl hydroperoxide, methyl ethyl ketone peroxide, benzoyl peroxide and the like can be mentioned. And it is good for the usage-amount of such a radical polymerization initiator to be about 0.1-30 mol% with respect to the total molar amount of a monomer.

  Further, as a photopolymerization initiator used in the latter photopolymerization method, acetophenone, p-anisyl, benzoyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-azobis (dimethylamino) benzophenone, benzoin methyl Ether, benzoin ethyl ether, methyl-2-benzoylbenzoate, 4,4'-dichlorobenzophenone, 2,2'-dimethoxy-2-diphenylacetophenone, 2-ethyl enthraquinone, 2-hydroxy-2-methylpropiophenone, Examples thereof include 2-hydroxy-4 ′-(2-hydroxyethoxy) -2-methylpropiophenone, 2-isonitrosopropiophenone and the like. And it is good for the usage-amount of such a photoinitiator to be about 0.1-30 mol% with respect to the total molar amount of a monomer.

  For example, 2-hydroxy-2-methylpropiophenone, which is one of the above-mentioned photopolymerization initiators, is activated by energy rays containing light with a wavelength of 300 to 400 nm, so a normal ultraviolet lamp is used as the energy ray source. Available. That is, in this photopolymerization initiator, as shown by the following chemical formula (III), the light of the above wavelength range is absorbed by UV irradiation to break the bond between C-C, 1-carboxyphenyl of the right side and 2 Generate both hydroxypropane radicals.

  Solvents used for the monomer solution in the solution polymerization method and photo polymerization method include acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, ethers such as dioxane and tetrahydrofuran, aliphatic hydrocarbons such as hexane, cyclohexane Cycloaliphatic hydrocarbons including, aromatic hydrocarbons including benzene, halogenated carbons such as dichloromethane and dichloroethane, esters such as ethyl acetate and methyl acetate, ethanol, isopropanol, butanol, cyclohexanol And alcohols such as methyl cellosolve, cellosolves such as ethyl cellosolve, cellosolve acetates, and amides such as dimethylformamide and dimethylacetamide. What good solubility of the monomers use may be appropriately selected.

  There is no particular limitation on other radically polymerizable monomers copolymerized with hexa (meth) acrylate, for example, (meth) acrylic acid, (meth) acrylic acid alkyl ester, styrenes, (meth) acrylonitrile, vinyl esters And (meth) acrylamides, maleic anhydride, maleimides, vinyl chloride, maleic esters, N-vinylamides and the like.

  As described above, the network polymer thus obtained has a non-directional, high density crosslinked structure, high hardness, excellent mechanical strength and heat resistance, and adhesion to the surface of inorganic materials such as glass and ceramic. For example, it is highly suitable as a hard coating material that protects the surface of an optical glass such as a display and a lens in various electronic devices. And in the copolymer of hexa (meth) acrylate and other radically polymerizable monomers, various properties and characteristics can be given by the kind of other radically polymerizable monomers, and the use ratio with respect to hexa (meth) acrylate. For example, when (meth) acrylic acid alkyl ester is used as another radically polymerizable monomer, the heat resistance of the copolymer to be formed can be controlled by the ratio of its use, so that the thermal characteristics according to the application of the polymer can be set. It has the advantage of

  Next, the method for producing the polyfunctional (meth) acrylate and the network polymer according to the present invention will be specifically described by way of examples. Myo-inositol, methacroyl chloride, t-butyl hydroquinone, triethylamine, acetonitrile, dichloromethane, ethyl acetate, ethyl methyl ketone, dimethyl formamide, lithium chloride, 1,4-dioxane, ethyl acetate, methyl methacrylate, butyl methacrylate and Acrylic acid is a high purity reagent manufactured by Wako Pure Chemical Industries, Ltd., DMAP and AIBN are high purity reagents manufactured by Kishida Chemical, and spherical silica gel for chromatography is a product name Wakogel C200 manufactured by Wako Pure Chemical Industries, Ltd. %) Were used respectively.

Example 1
In an eggplant flask, 1.80 g (10.0 mmol) of myo-inositol, 0.998 g (8.16 mmol) of DMAP and 3.3 mg (0.018 mmol) of t-butylhydroquinone were added, and the inside was replaced with argon, 34.0 ml (236 mmol) of triethylamine and 120 ml of acetonitrile were added, and the obtained solution was cooled with an ice bath, and 7.0 ml (89 mmol) of methacroyl chloride was added dropwise over 1 minute. Then, the solution is reacted by stirring at room temperature for 20 hours, 400 ml of brine is added to the reaction solution, extracted with 100 ml of ethyl acetate, the organic layer is dried over sodium sulfate and filtered, 3.3 mg of t-butylhydroquinone The reaction solution is concentrated under reduced pressure at 30 to 40 ° C., and the obtained concentrate is subjected to silica gel chromatography (developing solvent: acetonitrile), and the obtained pale yellow solid is re-used using a 10/3 mixed solvent of hexane / ethyl acetate. The crystallization gave 3.92 g (6.66 mmol) of white needles of hexamethacrylate. The yield of this synthesis reaction was about 67%. Moreover, it was 162.8-163.7 degreeC when the melting point of the white needle-like crystal of the obtained hexamethacrylate was measured.

About the hexamethacrylate obtained in Example 1, ¹ H-NMR spectrum and ¹³ C-NMR spectrum using nuclear magnetic resonance apparatus (trade name JNM-AL400 manufactured by JEOL Ltd. ... solvent: deuterated chloroform) Were measured, and the results shown in FIG. 1 and FIG. 2 were obtained. Moreover, when the infrared absorption spectrum was measured using the brand name FT / IR-4200 Spectrometer made from JASCO about the same hexamethacrylate, the result shown in the upper half described with the monomer of FIG. 4 was obtained.

〔result of analysis〕
From the ¹ H-NMR spectrum of FIG. 1, signals derived from two vinyl groups are confirmed at around 5.8 ppm and 5.7 ppm. Further, from the ¹³ C-NMR spectrum of FIG. 2, a signal derived from a carbonyl at 166 ppm, a signal derived from a vinyl group at around 135 ppm and 127 ppm, and a signal derived from a methyl group at around 18 ppm are respectively confirmed. On the other hand, in the infrared absorption spectrum (monomer) of FIG. 4, an absorption peak due to carbonyl appears near 1728 cm ⁻¹ . From these results, the compound was proved to be inositol hexamethacrylate.

Example 2
In the same manner as in Example 1 except that the same amount of dichloromethane was used in place of acetonitrile as the solvent used in Example 1, 2.91 g (4.94 mmol) of white needle crystals of hexamethacrylate were obtained. The yield of this synthesis reaction was about 49%.

Reference Examples 1 to 3
Instead of the acetonitrile used as the solvent in Example 1, a mixed solvent of ethyl acetate in Reference Example 1, ethyl methyl ketone in Reference Example 2 and a dimethylphoramide / lithium chloride weight ratio of 10 / 0.6 in Reference Example 3 is used. The reaction was carried out in the same manner as in Example 1 except that they were used in the same amount, but none could synthesize hexamethacrylate.

Example 3
The hexamethacrylate obtained in Example 1 and 1 mol% of AIBN with respect to the number of moles thereof are added and dissolved in 1,4-dioxane, and stirred at a liquid temperature of 65 ° C. for 20 hours in an argon atmosphere. A methacrylate homopolymer was synthesized by reacting the reaction product. At this stage, the homopolymer was in a gel state swollen by 1,4-dioxane. This gel was crushed with a spatula, poured into methanol and stirred, and the formed solid was suction filtered and dried under reduced pressure to obtain a network polymer composition.

The solid-state NMR spectrum of the network polymer obtained in Example 3 was measured using the same nuclear magnetic resonance apparatus, and the results shown in FIG. 3 were obtained. The infrared absorption spectrum of the same network polymer was also obtained. Was measured in the same manner as described above, and the results shown in the lower half of the polymers shown in FIG. 4 were obtained. In the solid-state NMR spectrum of FIG. 3, signals derived from vinyl groups are observed at around 136 ppm and 126 ppm, and in the infrared absorption spectrum (polymer) of FIG. 4, an absorption peak by carbonyl appears at around 1735 cm ^−1. It was confirmed that the network polymer was a homopolymer of inositol hexamethacrylate.

Example 4
The hexamethacrylate and methyl methacrylate obtained in Example 1 and AIBN corresponding to 2 mol% with respect to the total moles of monomers are added and dissolved in 1,4-dioxane, and the solution temperature is 65 in argon atmosphere. In a method of obtaining a network polymer composition by reacting at 20 ° C. with stirring for 20 hours in the same manner as in Example 3, hexamethacrylate and methyl methacrylate are used as the respective use ratios described in Table 1 below as network polymer compositions. The synthesis of (homopolymer and copolymer) was performed. The yield, the 5% weight loss temperature (T _d5 ) and the 10% weight loss temperature (T _d10 ) were examined for each of the obtained network polymers, and the results shown in Table 1 were obtained. In the Table, MMA means methyl methacrylate and HM means hexamethacrylate.

  As shown in Table 1, in the copolymer of hexamethacrylate and methyl methacrylate, much higher heat resistance is obtained with substantially the same yield as the homopolymer of methyl methacrylate, and the heat resistance is hexamethacrylate. It can be seen that the higher the ratio of, the better. However, it can be seen that the homopolymer of hexamethacrylate exhibits much higher heat resistance with a much higher yield than the copolymer.

Example 5
In the same manner as in Example 4 except that butyl methacrylate was used in place of methyl methacrylate used in Example 4, hexamethacrylate and butyl methacrylate were in respective molar ratios described in Table 2 below as network polymers. The synthesis of (homopolymer and copolymer) was performed. The yield, the 5% weight loss temperature (T _d5 ) and the 10% weight loss temperature (T _d10 ) were examined for each of the obtained network polymers, and the results shown in Table 2 were obtained. In the table, BMA means butyl methacrylate and HM means hexamethacrylate.

  As shown in Table 2, in the copolymer of hexamethacrylate and butyl methacrylate, the heat resistance is also remarkably improved with a much higher yield than the homopolymer of butyl methacrylate, and the yield and the heat resistance are Both the higher the proportion of hexamethacrylate, the better, but it can be seen that the heat resistance is lower than that of the hexamethacrylate homopolymer.

Example 6
The hexamethacrylate and acrylic acid (molar ratio 1:58) obtained in Example 1, and 4.8 mol% of 2-hydroxy-2-methylpropiophenone relative to the total number of moles of both monomers, The solution was added and dissolved in 4-dioxane, and this solution was irradiated with ultraviolet light having a wavelength of 365 nm for 30 minutes using a UV lamp (trade name XX-15BLB manufactured by Amarity Quyena US Endreshauser Company, Inc.), causing gelation. Network polymer formed. The 5% weight loss temperature (T _d5 ) of this network polymer was 270 ° C., and the 10% weight loss temperature (T _d10 ) was 330 ° C.

Example 7
The hexamethacrylate obtained in Example 1 and butyl methacrylate (molar ratio 5: 95), and 4.0 mol% of 2-hydroxy-2-methylpropiophenone relative to the total number of moles of both monomers, 1 The solution is added to and dissolved in 4-, 4-dioxane, and this solution is coated on a glass surface at a rate of 100 μl / cm ² , and UV light with a wavelength of 365 nm is applied to the coated surface using the same UV lamp as in Example 6. When irradiated for 30 minutes, the coating was cured to form a colorless and transparent very hard hard coat layer. The hard coat layer was firmly fixed to the glass surface and could not be peeled off even with a spatula.

Claims (9)

  A process for producing a polyfunctional (meth) acrylate, comprising reacting inositol and (meth) acryloyl chloride in a solvent in the presence of an esterification catalyst.   The method for producing a polyfunctional (meth) acrylate according to claim 1, wherein the solvent is at least one selected from a nitrile solvent and a halogen solvent.   The method for producing a polyfunctional (meth) acrylate according to claim 1, wherein the solvent is acetonitrile.   The method for producing a multifunctional (meth) acrylate according to any one of claims 1 to 3, wherein a basic compound is added to the reaction system to neutralize hydrogen chloride by-produced in the reaction.   The method for producing a polyfunctional (meth) acrylate according to any one of claims 1 to 4, wherein the esterification catalyst is N, N-dimethyl-4-aminopyridine.   The method for producing a polyfunctional (meth) acrylate according to any one of claims 1 to 5, wherein the polyfunctional (meth) acrylate is hexa (meth) acrylate.   A network polymer characterized by radically polymerizing a single monomer of a polyfunctional (meth) acrylate obtained by the method according to any one of claims 1 to 6 or a mixed monomer with another radically polymerizable monomer. Manufacturing method.   8. The method according to claim 7, wherein radical polymerization of the polyfunctional (meth) acrylate monomer alone or a mixed monomer with another radically polymerizable monomer is carried out by active energy ray irradiation in the presence of a photopolymerization initiator. Network polymer manufacturing method.   The method for producing a network polymer according to claim 7 or 8, wherein the other radically polymerizable monomer is (meth) acrylic acid alkyl ester.