Mesogen group-containing ester compound

Abstract

To provide a mesogen group-containing ester compound, which serves as a raw material for a thermoresponsive polymer, with superior breaking strength.SOLUTION: A mesogen group-containing ester compound is synthesized by the addition of a carboxyl group-containing compound or a lactone compound to a compound A with an active hydrogen group. Preferably, the compound A is a compound represented by the formula (1) (where X is an active hydrogen group, R1 is a single bond forming a part of an adjacent linking group, -N=N-, -CO-, -CO-O-, or -CH=N-, R2 is a single bond forming a part of an adjacent linking group, or -O-, R3 is a single bond forming a part of an adjacent linking group, or a C1-20 alkylene group, excluding the case where R2 is -O- and R3 is a single bond forming a part of an adjacent linking group).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a mesogen-containing ester compound. [Background technology]

[0002] Thermoresponsive polymers exhibit a characteristic response behavior of expanding and contracting in response to external stimuli such as heat, and therefore attempts have been made to apply them to various fields such as actuators. An example of a thermoresponsive polymer is a liquid crystal elastomer.

[0003] The following Patent Document 1 describes a liquid crystal compound in which alkylene oxide and / or styrene oxide is added to a mesogen group-containing compound as a raw material for a liquid crystal elastomer.

[0004] Furthermore, the following Patent Document 2 describes, as a liquid crystal elastomer, a photocrosslinkable liquid crystal polymer composed of a photocrosslinking pre-reaction product of a mesogen group-containing compound having an active hydrogen group, a diisocyanate compound, a photopolymerizable group-containing compound having a hydroxyl group, and a photocuring initiator, the photocrosslinkable liquid crystal polymer containing 1 to 10% by weight of the photopolymerizable group-containing compound having a hydroxyl group. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6396130 [Patent Document 2] Patent No. 7112332 Summary of the Invention [Problem to be solved by the invention]

[0006] The thermoresponsive liquid crystal polymer obtained by crosslinking the photocrosslinkable liquid crystal polymer obtained from the liquid crystal compound is a useful material for many applications because it has liquid crystallinity and rubber elasticity at low temperatures (around room temperature). However, as a result of the inventor's investigation, it was found that there is room for further improvement in terms of breaking strength compared to the materials described in the above patent documents, since high breaking strength is required for cords such as cap plies of pneumatic tires, for example, when the thermoresponsive liquid crystal polymer is used.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mesogen group-containing ester compound that can be used as a raw material for a thermoresponsive polymer having excellent breaking strength. [Means for solving the problem]

[0008] The above object can be achieved by the following constitution: That is, the present invention relates to a mesogen group-containing ester compound (1) in which a carboxy group-containing compound or a lactone compound is added to a compound A having an active hydrogen group.

[0009] In the above mesogenic group-containing ester compound (1), the compound A is represented by the following formula (1): [ka] (in formula (1), X is an active hydrogen group; R1 is a single bond forming a part of the adjacent bonding group, -N=N-, -CO-, -CO-O-, or -CH=N-; R2 is a single bond forming a part of the adjacent bonding group or -O-; and R3 is a single bond forming a part of the adjacent bonding group or an alkylene group having 1 to 20 carbon atoms, except for the case where R2 is -O- and R3 is a single bond forming a part of the adjacent bonding group).

[0010] In the above mesogenic group-containing ester compound (1) or (2), a mesogenic group-containing ester compound (3) represented by the following formula in which the ester bond ratio is 5 to 30% is preferred.

number

[0011] Of the above mesogenic group-containing ester compounds (1) to (3), the mesogenic group-containing ester compound (4) in which the lactone compound is ε-caprolactone is preferred.

[0012] In the above mesogenic group-containing ester compound (4), a mesogenic group-containing ester compound (5) in which the average amount of ε-caprolactone added per 1 mol of compound A is 0.6 to 13 mol is preferred.

[0013] Of the above mesogenic group-containing ester compounds (1) to (5), the mesogenic group-containing ester compound (6) in which the carboxyl group-containing compound is glycolic acid or lactic acid is preferred. Effect of the Invention

[0014] Up to now, mesogen group-containing compounds in which alkylene oxide and / or styrene oxide are added to mesogen group-containing compounds (hereinafter also referred to as "ether-based mesogen group-containing compounds") have been known, but there is room for further improvement in terms of breaking strength for thermoresponsive polymers obtained by crosslinking photocrosslinkable polymers obtained using ether-based mesogen group-containing compounds as raw materials. The present inventor has newly developed a mesogen group-containing ester compound in which a carboxy group-containing compound or a lactone compound is added to a compound A having an active hydrogen group, and in such a mesogen group-containing ester compound, ε-caprolactone is added to the compound A having an active hydrogen group while opening the ring, or a carboxy group-containing compound is added to the compound A, so that the mesogen group-containing compound has an ester bond. As a result of intensive research by the present inventors, it was found that a mesogen group-containing ester compound having a structure in which an ester bond is added to a mesogen group-containing compound, which is a thermoresponsive polymer, tends to crystallize upon stretching (stretching crystallization) when used in applications in which the polymer is stretched in the longitudinal direction, such as fibers, and that the formation of the stretching crystallization upon stretching significantly increases the breaking strength of the thermoresponsive polymer.

[0015] As described above, the mesogen group-containing ester compound according to the present invention has a structure with an ester bond added thereto, and therefore when used as a raw material for a thermoresponsive polymer, the breaking strength of the thermoresponsive polymer is significantly increased due to the formation of elongated crystals during elongation. This effect is significantly higher than when a conventional ether-based mesogen group-containing compound is used as a raw material for a thermoresponsive polymer. Therefore, the thermoresponsive polymer obtained by using the mesogen group-containing ester compound according to the present invention as a raw material is particularly useful for applications requiring excellent breaking strength, such as cords for cap plies of pneumatic tires. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The mesogen group-containing ester compound according to the present invention is a mesogen group-containing ester compound in which a carboxy group-containing compound or a lactone compound is added to a compound A having an active hydrogen group.

[0017] As the compound A having an active hydrogen group, for example, a compound represented by the following general formula (1) can be used. [ka]

[0018] In the above general formula (1), X is an active hydrogen group, R1 is a single bond forming a part of an adjacent bonding group, -N=N-, -CO-, -CO-O-, or -CH=N-, R2 is a single bond forming a part of an adjacent bonding group, or -O-, and R3 is a single bond forming a part of an adjacent bonding group, or an alkylene group having 1 to 20 carbon atoms. However, this does not include cases where R2 is -O- and R3 is a single bond forming a part of an adjacent bonding group. In addition, the "single bond forming a part of an adjacent bonding group" means a state in which the single bond is shared with a part of an adjacent bonding group. For example, in the above general formula (1), when R1 is a single bond forming a part of an adjacent bonding group, R1, which is a single bond, is shared with the benzene rings on both sides, and forms a biphenyl structure together with the benzene rings on both sides. Examples of X include OH, SH, NH2, COOH, and secondary amines.

[0019] In the present invention, the compound A having an active hydrogen group is preferably a compound represented by the following formula (2) (hereinafter, also referred to as "BH6"). [ka]

[0020] In the present invention, the compound A having an active hydrogen group used as a raw material may be used alone or in combination of two or more kinds.

[0021] The mesogen group-containing ester compound according to the present invention is a mesogen group-containing ester compound obtained by adding a carboxyl group-containing compound or a lactone compound to a compound A having an active hydrogen group. As the lactone compound, ε-caprolactone is preferable. From the viewpoint of improving the breaking strength of the thermoresponsive polymer by forming an elongated crystal during elongation, the average addition amount of the ε-caprolactone to 1 mole of the compound A having an active hydrogen group is preferably 0.6 to 13 moles, and more preferably 0.6 to 12 moles. In the present invention, the "average addition amount of ε-caprolactone to the compound A having an active hydrogen group" means the average addition molar amount of ε-caprolactone to 1 mole of the compound A having an active hydrogen group, and the average addition amount (mol) can be calculated, for example, by measuring the hydroxyl value (OHV).

[0022] The mesogen group-containing ester compound according to the present invention is preferably a mesogen group-containing ester compound in which ε-caprolactone is added to a compound A having an active hydrogen group, but in addition to ε-caprolactone, a compound other than ε-caprolactone, such as alkylene oxide and / or styrene oxide, may be added to the compound A having an active hydrogen group. The alkylene oxide to be added is not particularly limited, and examples thereof include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, cyclohexene oxide, epichlorohydrin, epibromohydrin, methyl glycidyl ether, and allyl glycidyl ether. The styrene oxide to be added may have a substituent such as an alkyl group, an alkoxyl group, or a halogen on the benzene ring. However, from the viewpoint of improving the breaking strength of the thermoresponsive polymer by forming elongated crystals during elongation, it is preferable that the amount of ε-caprolactone added to compound A having an active hydrogen group is larger than that of other alkylene oxides and / or styrene oxides, and it is more preferable that only ε-caprolactone is added to compound A having an active hydrogen group.

[0023] The mesogen group-containing ester compound according to the present invention is a mesogen group-containing ester compound obtained by adding a carboxyl group-containing compound or a lactone compound to a compound A having an active hydrogen group. As the carboxyl group-containing compound, glycolic acid or lactic acid is preferable. From the viewpoint of improving the breaking strength of the thermoresponsive polymer by forming an elongated crystal during elongation, the average addition amount of the glycolic acid or lactic acid to 1 mole of the compound A having an active hydrogen group is preferably 0.6 to 13 moles, and more preferably 0.6 to 12 moles. In the present invention, the "average addition amount of glycolic acid or lactic acid to the compound A having an active hydrogen group" means the average addition molar amount of glycolic acid or lactic acid to 1 mole of the compound A having an active hydrogen group, and the average addition amount (mol) can be calculated, for example, by measuring the hydroxyl value (OHV).

[0024] The mesogen group-containing ester compound according to the present invention is particularly useful as a raw material for a thermoresponsive polymer. The thermoresponsive polymer can be produced, for example, by producing a photocrosslinkable polymer, which is a reaction product of the mesogen group-containing ester compound according to the present invention, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group, and crosslinking the photocrosslinkable polymer.

[0025] In addition, when an antioxidant is added to the mesogen group-containing ester compound according to the present invention, it is preferable because it can suppress the generation of radicals derived from the mesogen group-containing ester compound and suppress the increase in viscosity of the mesogen group-containing ester compound and the photocrosslinkable polymer described below. When an antioxidant is added to the mesogen group-containing ester compound, the timing of addition may be any of the following: a storage stage or drying stage of the mesogen group-containing ester compound, a stage of producing a photocrosslinkable polymer by reacting the mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group in the presence of a photoreaction initiator, and a storage stage of the obtained photocrosslinkable polymer.

[0026] Any antioxidant known to those skilled in the art can be used, but at least one selected from the group consisting of phenol-based antioxidants and hindered amine-based antioxidants is preferred, as this can effectively suppress the amount of radicals generated from the mesogen group-containing ester compound.

[0027] The phenol-based antioxidant is preferably one having an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, or a t-butyl group at a position adjacent to the hydroxy group of the phenol ring, and particularly preferably one having a t-butyl group at a position adjacent to the hydroxy group of the phenol ring. In this case, the hydroxy group (active hydrogen group) of the phenol-based antioxidant is protected by the t-butyl group, which has a bulky structure, and the reactivity with the isocyanate group of the isocyanate compound is reduced, so that the deactivation of the antioxidant's antioxidant ability can be suitably suppressed. Examples of phenol-based antioxidants having a t-butyl group at a position adjacent to the hydroxy group of the phenol ring include 2,6-di-t-butyl-p-cresol (BHT), 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 4,4',4''-(1-methylpropanyl-3-ylidene)tris(6-t-butyl-m-cresol), 6,6'-di-t-butyl-4,4'-butylidene-m-cresol, octadecyl 3-(3, 5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3,5-tris(3,5-di-t-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, and the like. As the phenol-based antioxidant having a t-butyl group at a position adjacent to a hydroxy group, commercially available products can also be used, and in particular, BHT (manufactured by Tokyo Chemical Industry Co., Ltd.), ADK STAB AO-60 / ADK STAB AO-60G (octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, manufactured by ADEKA Corporation), and ADK STAB AO-80 (3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, manufactured by ADEKA Corporation) are preferably used.Other commercially available phenol-based antioxidants that can be used include Sumilizer GS(F) (manufactured by Sumitomo Chemical), Sumilizer GM(F) (manufactured by Sumitomo Chemical), Sumilizer GA80 (manufactured by Sumitomo Chemical), Sumilizer MDP-S (manufactured by Sumitomo Chemical), WX-R (manufactured by Sumitomo Chemical), WX-RC (manufactured by Sumitomo Chemical), Irganox1010 (manufactured by BASF), 1035 (manufactured by BASF), 1076 (manufactured by BASF), 1135 (manufactured by BASF), and 1726 (manufactured by BASF).

[0028] The hindered amine antioxidant is preferably a compound in which hydrogen or an alkyl group, particularly a methyl group, is bonded to a nitrogen atom, and commercially available products can also be used. Examples of such commercially available products include ADK STAB LA-52 (manufactured by ADEKA Corporation), ADK STAB LA-57 (manufactured by ADEKA Corporation), ADK STAB LA-63P (manufactured by ADEKA Corporation), ADK STAB LA-68 (manufactured by ADEKA Corporation), ADK STAB LA-72 (manufactured by ADEKA Corporation), ADK STAB LA-77Y (manufactured by ADEKA Corporation), ADK STAB LA-81 (manufactured by ADEKA Corporation), ADK STAB LA-82 (manufactured by ADEKA Corporation), ADK STAB LA-87 (manufactured by ADEKA Corporation), ADK STAB LA-402AF (manufactured by ADEKA Corporation), ADK STAB LA-40MP (manufactured by ADEKA Corporation), Tinuvin 123 (manufactured by BASF Corporation), Tinuvin 1144 (manufactured by BASF Corporation), Tinuvin 152 (manufactured by BASF Corporation), Tinuvin 249 (manufactured by BASF Corporation), Tinuvin 292 (manufactured by BASF), Tinuvin 770DF (manufactured by BASF), Tinuvin 5100 (manufactured by BASF). The reason why the hindered amine antioxidant has an effect of inhibiting the oxidation of mesogen group-containing ester compounds is considered to be as follows. Hindered amine antioxidants are generally used as light stabilizers, and various mechanisms of action have been proposed, but it is believed that the light stabilizing effect is mainly due to the radical scavenging effect. Since the effect of inhibiting the oxidation of mesogen group-containing ester compounds is achieved by radical scavenging, the oxidation of mesogen group-containing ester compounds can also be inhibited by hindered amine antioxidants.

[0029] As the antioxidant, antioxidants other than phenol-based antioxidants and hindered amine-based antioxidants can also be used, such as phenothiazine, which is a thiazine-based antioxidant. Phenothiazine is also preferred because it has low reactivity with the isocyanate group of the isocyanate compound and can suitably suppress the loss of antioxidant ability.

[0030] When an antioxidant is added to the mesogen group-containing ester compound according to the present invention, a phenol-based antioxidant or a hindered amine-based antioxidant may be used alone or in combination of two or more kinds.

[0031] In order to suppress the increase in viscosity of the mesogen group-containing ester compound and the photocrosslinkable polymer described later and improve the moldability thereof, the amount of the antioxidant is preferably 0.006 to 10 parts by mass, more preferably 0.05 to 2.5 parts by mass, when the total amount of the mesogen group-containing ester compound is taken as 100 parts by mass. Furthermore, the concentration of the antioxidant in the photocrosslinkable polymer composition is preferably 30 to 30,000 ppm, more preferably 400 to 7,000 ppm. In addition, when the photocrosslinkable polymer composition contains an isocyanate compound, the effect of the antioxidant in suppressing radical generation may be reduced by reaction with the isocyanate group of the isocyanate compound. Therefore, when the photocrosslinkable polymer composition contains an isocyanate compound, the proportion of the antioxidant is preferably 0.015 to 20% by mass, more preferably 0.2 to 5% by mass, when the total amount of the isocyanate compound before the reaction is taken as 100% by mass.

[0032] As the isocyanate compound, for example, the diisocyanate compounds shown below can be used. Examples of the diisocyanate compound include aromatic diisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, and m-xylylene diisocyanate; ethylene diisocyanate; aliphatic diisocyanates such as 1,5-pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene-1,6-diisocyanate, 2,4,4-trimethylhexamethylene-1,6-diisocyanate, and 1,6-hexamethylene diisocyanate; and alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornane diisocyanate. The diisocyanate compounds exemplified above may be used alone or in combination. In the present invention, a trifunctional or higher isocyanate compound may be used in combination as the isocyanate compound, but in order to ensure the thermoplasticity of the resulting photocrosslinkable polymer, when the total amount of the isocyanate compounds used is taken as 100 mass%, the ratio of the diisocyanate compound is preferably 98 mass% or more, more preferably 99 mass% or more, and even more preferably approximately 100 mass%. Examples of trifunctional or higher isocyanate compounds include triisocyanates such as triphenylmethane triisocyanate, tris(isocyanate phenyl)thiophosphate, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, and bicycloheptane triisocyanate, and tetraisocyanates such as tetraisocyanate silane.

[0033] When the total amount of the mesogen group-containing ester compound constituting the photocrosslinkable polymer is 100 parts by mass, the ratio of the isocyanate compound is preferably 5 to 60 parts by mass, more preferably 10 to 50 parts by mass. If the amount of the isocyanate compound is less than 5 parts by mass, the polymerization by the urethane reaction becomes insufficient, so that it becomes difficult to continuously mold the photocrosslinkable polymer. On the other hand, if the amount of the isocyanate compound is more than 60 parts by mass, the amount of the mesogen group-containing ester compound in the total raw material of the photocrosslinkable polymer becomes relatively small, so that the stretchability of the photocrosslinkable polymer and the thermoresponsive polymer decreases.

[0034] The isocyanate group of the isocyanate compound can react with an active hydrogen group such as a hydroxyl group of the mesogen group-containing compound and an active hydrogen group such as a hydroxyl group of the photopolymerizable group-containing compound. NCO INDEX (NCO / OH), which is the theoretical amount of the isocyanate group of the isocyanate compound relative to the theoretical amount of the active hydrogen groups of the mesogen group-containing ester compound and the photopolymerizable group-containing compound, is preferably 0.95 to 1.30, more preferably 1.00 to 1.20.

[0035] The photopolymerizable group-containing compound having an active hydrogen group can be, for example, an acryloyl group-containing compound, a methacryloyl group-containing compound, or an allyl compound. Examples of the acryloyl group-containing compound include propylene glycol diglycidyl ether acrylic acid adduct, ethylene glycol diglycidyl ether methacrylic acid adduct, tripropylene glycol diglycidyl ether acrylic acid adduct, glycerin diglycidyl ether acrylic acid adduct, bisphenol A Examples of the PO 2mol adduct include diglycidyl ether acrylic acid adduct, 2-acryloyloxyethyl succinate, β-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, 2-acryloyloxyethyl acid phosphate, 2-hydroxy-3-acryloyloxypropyl methacrylate, and pentaerythritol triacrylate. Examples of methacryloyl group-containing compounds include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl acid phosphate, glycerin dimethacrylate, bisphenol A PO 2 mol adduct diglycidyl ether methacrylic acid adduct, bisphenol A diglycidyl ether methacrylic acid adduct, 2-hydroxy-3-acryloyloxypropyl methacrylate, 2-methacryloyloxyethyl succinate, etc. Examples of allyl group-containing compounds include glycerin monoallyl ether, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, etc.

[0036] When the total amount of the mesogen group-containing ester compounds constituting the photocrosslinkable polymer is 100 parts by mass, the ratio of the photopolymerizable group-containing compound is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass. When the ratio of the photopolymerizable group-containing compound is less than 0.1 parts by mass, the raw material is not sufficiently cured even when irradiated with light, so that the generated thermoresponsive polymer is difficult to exhibit thermoresponsiveness. When the ratio of the photopolymerizable group-containing compound is more than 10 parts by mass, the crosslink density in the polymer after irradiation with light becomes too high, so that in this case too, the generated thermoresponsive polymer is difficult to exhibit thermoresponsiveness.

[0037] A crosslinking agent having three or more active hydrogen groups may be used as a raw material for the photocrosslinkable polymer. Examples of the crosslinking agent include polyol compounds and amine compounds having three or four active hydrogen groups. Examples of the polyol compounds include trimethylolpropane, glycerin, 1,2,6-hexanetriol, diglycerin, methyl glucoside, pentaerythritol, tetramethylolcyclohexane, and polyether polyols obtained by adding an ether compound to a trifunctional initiator (trimethylolpropane, glycerin, etc.) or a tetrafunctional initiator (pentaerythritol, diglycerin, diethyleneamine, etc.). Examples of the amine compounds include methanetriamine, diethylenetriamine, and 2-(2-aminoethylamino)ethanol.

[0038] When producing a photocrosslinkable polymer, in addition to the mesogen group-containing ester compound, the isocyanate compound, and the photopolymerizable group-containing compound having an active hydrogen group, an active hydrogen group-containing compound may be used as the raw material of the photocrosslinkable polymer. Examples of the active hydrogen group-containing compound include polyol compounds and amine compounds. Examples of the polyol compound include polyether polyol, polyester polyol, polycarbonate polyol, polyester polycarbonate polyol, polycaprolactone polyol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and 1,4-bis(2-hydroxyethoxy)benzene. The above-listed active hydrogen group-containing compounds may be used alone or in combination.

[0039] When a mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group are reacted, a urethane polymerization catalyst known to those skilled in the art may be used. Examples of such polymerization catalysts include organic titanium catalysts such as titanium tetra-n-butoxide, titanium tetra-2-ethylhexoxide, titanium tetraacetylacetonate, and titanium diisopropoxybis(ethylacetoacetate), organic zirconium catalysts such as zirconium tetra-n-butoxide, zirconium dibutoxybis(ethylacetoacetate), zirconium tetraacetylacetonate, and zirconium tetraacetylacetonate, organic zinc catalysts such as zinc naphthenate, dibutyltin dilaurate, and octyl Examples of suitable catalysts include organotin catalysts such as tin oxide, triethylenediamine and its derivatives, tertiary amine catalysts such as N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), bis(N,N-dimethylamino-2-ethyl)ether, and bis(2-dimethylaminoethyl)ether, carboxylate metal salt catalysts such as potassium acetate and potassium octylate, and imidazole catalysts. Among these, triethylenediamine and its derivatives are preferably used.

[0040] When producing a reaction product of a mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group, it is preferable to add a photoreaction initiator.

[0041] Photoinitiators include, for example, 1-hydroxy-cyclohexyl-phenyl-ketone, bis(2,4,6-trimethylbenzoyl)-phenylphosphonoxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone / benzophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-his hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester / oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, phenylglyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)furan phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), iodonium, (4-methylphenyl) [4-(2-methylpropyl)phenyl]-hexafluorophosphate (1-) / propylene carbonate, triarylsulfonium hexafluorophosphate, triarylsulfonium tetrakis-(pentafluorophenyl)borate, and oxime sulfonate-based photoacid generators can be used.When the total amount of the mesogen group-containing ester compound constituting the photocrosslinkable polymer is 100 parts by mass, the ratio of the photoinitiator is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 8 parts by mass. When the amount of the photoinitiator is less than 0.05 parts by mass, the polymerization reaction does not proceed uniformly during light irradiation, or the curing is insufficient, so that the generated polymer is difficult to exhibit thermal responsiveness. When the amount of the photoinitiator is more than 10 parts by mass, the content of the mesogen group in the generated polymer decreases, so that the thermal responsiveness is difficult to exhibit. The photoinitiator preferably has an absorption wavelength of 200 to 600 nm. If the photoinitiator has an absorption wavelength in the above range, the photoinitiator can absorb light and reliably proceed with the photocrosslinking reaction, even if the transparency (transmittance of visible light) of the photocrosslinkable polymer or its raw material is low.

[0042] The photocrosslinkable polymer described above is a raw material for a thermoresponsive polymer. The photocrosslinkable polymer can be produced by reacting a mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group in the presence of a photoreaction initiator. The reaction conditions for the reaction include, for example, a method in which a mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group are charged into an extrusion molding machine together with a photoreaction initiator, and reacted while being heated and melted at, for example, 60 to 150°C.

[0043] The photocrosslinkable polymer composition containing the photocrosslinkable polymer and the photoreaction initiator is cooled, pulverized and molded into pellets, and the pelletized raw material is molded into a predetermined shape using an extrusion molding machine, and then extrusion-molded while stretching at a temperature range of glass transition temperature (Tg) or higher and phase transition temperature (Ti) or lower. Alternatively, in the presence of a photoreaction initiator, the reaction product (photocrosslinkable polymer) of a mesogen group-containing ester compound, an isocyanate compound, and a photopolymerizable group-containing compound having an active hydrogen group may be extrusion-molded while stretching in a temperature range of glass transition temperature (Tg) or higher and phase transition temperature (Ti) or lower. In this case, the mesogen group contained in the mesogen group-containing ester compound moves along the stretching direction, so that a molded product of a photocrosslinkable polymer having a high degree of orientation can be produced.

[0044] When the molded product of the photocrosslinkable polymer having a high degree of orientation obtained above is molded into an appropriate shape and cooled, and irradiated with light having a wavelength of 200 to 600 nm while maintaining the stretched state, a crosslinking reaction proceeds between the raw materials while maintaining the orientation, and a thermoresponsive polymer with elasticity according to temperature change is completed. The thermoresponsive polymer produced in this way shows a specific thermoresponsive behavior in which the mesogen groups are oriented in the stretching direction in the low temperature region, but when heated and exceeds the phase transition temperature (Ti), the orientation of the mesogen groups is broken (becomes irregular) and the polymer shrinks in the stretching direction, and when cooled and falls below the phase transition temperature (Ti), the orientation of the mesogen groups is restored and the polymer stretches in the stretching direction.

[0045] Incidentally, the orientation of thermoresponsive polymers can be evaluated by the degree of orientation of the mesogen groups. A high degree of orientation indicates that the mesogen groups are highly oriented in one axis direction. The degree of orientation is calculated by measuring the absorbance (0°, 90°) of the antisymmetric stretching vibration of aromatic ether and the absorbance (0°, 90°) of the symmetric bending vibration of methyl groups using a single-pass attenuated total reflection (ATR) measurement method with a Fourier transform infrared spectrophotometer (FT-IR), and using these absorbances as parameters, based on the following formula: Orientation degree=(AB) / (A+2B) A: Absorbance of the antisymmetric stretching vibration of aromatic ether measured at 0° / absorbance of the symmetric bending vibration of the methyl group measured at 0° B: Absorbance of the antisymmetric stretching vibration of aromatic ether measured at 90° / absorbance of the symmetric bending vibration of methyl group measured at 90°

[0046] In order for the thermoresponsive polymer to exhibit significant stretchability, the degree of orientation of the mesogen groups is preferably 0.05 or more, and more preferably 0.1 or more. EXAMPLES

[0047] Examples that specifically show the configuration and effects of the present invention will be described below. The evaluation items in the examples were measured as follows.

[0048] <Phase transition temperature (Ti)> The phase transition temperatures (Ti) of the mesogen-containing ester compounds and the thermoresponsive polymers obtained by photocrosslinking the photocrosslinkable polymers were measured using a differential scanning calorimeter [DSC] (product name: X-DSC 7000, manufactured by Hitachi High-Tech Science Corporation).

[0049] <Breaking strength of thermoresponsive polymer> The breaking strength was measured for the thermoresponsive polymer obtained by photocrosslinking the photocrosslinkable polymer obtained from the mesogen group-containing ester compound. Specifically, the resin pellets of the photocrosslinkable polymer, which is the raw material of the thermoresponsive polymer, were first molded into a 0.5 mm resin sheet using a compression molding machine (product name: NSF-37, manufactured by Shinto Metal Industries Co., Ltd.) set at a temperature of ±20°C from the Ti of the photocrosslinkable polymer. This sheet was punched into a dumbbell-shaped No. 8 (JIS K 6251), stretched 7 times, and irradiated with light to cause a photocrosslinking reaction to produce a thermoresponsive polymer. The breaking strength was measured for the thermoresponsive polymer (width: 1.5 mm, thickness: 0.2 mm) by using an autograph (product name: AG-X, manufactured by Shimadzu Corporation) at a tensile speed of 135 mm / min, a gauge length of 70 mm, and a tensile test according to JIS K 6251). The evaluation was performed using an index based on the breaking strength of the thermoresponsive polymer of Production Example 21 produced from the mesogen group-containing compound A produced in Comparative Example 1 as a raw material, which was set at 100. A larger value indicates better breaking strength. The results are shown in Table 3.

[0050] <Stretching behavior of thermoresponsive polymers> For the thermoresponsive polymer obtained by photocrosslinking a photocrosslinkable polymer obtained from a mesogen group-containing ester compound, the size reduction in the orientation direction (reduction in the length of the sample, referred to as "α") that occurs with a temperature change from 35 to 155°C and the size increase (increase in the length of the sample, referred to as "β") that occurs with a temperature change from 35 to 155°C were measured on a scale, and those where α<β were judged to have sufficient stretching behavior as a thermoresponsive polymer. The results are shown in Table 3. In Table 3, cases where the stretching behavior was sufficient are indicated as "○".

[0051] [Production Example of Mesogen Group-Containing Ester Compound] Example 1 BH6 (400 g) represented by the following formula (2), ε-caprolactone (248 g), and toluene (4200 ml) were added and heated to 110° C. After adding tin(II) 2-ethylhexanoate (2 g), the reaction solution was stirred at 110° C. for 4 hours. Toluene was then removed by distillation under reduced pressure to obtain the target mesogenic group-containing ester compound A represented by the following formula (3). The average molar amount of ε-caprolactone added per mole of BH6 (average amount of ε-caprolactone added (mol)) and the phase transition temperature (Ti) of the mesogenic group-containing ester compound are shown in Table 1. [ka] [ka]

[0052] Examples 2 to 6 Mesogenic group-containing ester compounds B to F were obtained in the same manner as in Example 1, except that the amount of ε-caprolactone added was changed so that the average amount (mol) of ε-caprolactone added per 1 mol of BH6 was the amount shown in Table 1.

[0053] Example 7 BH6 (400 g), L-lactic acid (140 g), and toluene (4200 ml) shown in the above formula (2) were added and heated to 110°C. After p-toluenesulfonic acid (20 g) was added, the reaction solution was heated to reflux at 110°C for 4 hours while removing water generated by the reaction using a DeanStak. Sodium bicarbonate was then added to neutralize the mixture, and the organic layer was washed with water using a separatory funnel. The toluene in the organic layer was then removed by distillation under reduced pressure to obtain the target mesogen group-containing ester compound G shown in the following formula (4). The average molar amount of L-lactic acid added to 1 mole of BH6 (average amount of L-lactic acid added (mol)) and the phase transition temperature (Ti) of the mesogen group-containing ester compound are shown in Table 1. [ka]

[0054] Comparative Example 1 BH6 (500 g) as a mesogen group-containing compound having an active hydrogen group, potassium hydroxide (7 g), and toluene (500 ml) as a solvent were mixed in a reaction vessel, and further, propylene oxide was added in an amount of 4.2 equivalents per mole of BH6 instead of ε-caprolactone, and the mixture was reacted at 120°C for 3 hours under pressure (addition reaction). Next, oxalic acid (10 g) was added to the reaction vessel to terminate the addition reaction, and the insoluble salt in the reaction solution was removed by suction filtration. Furthermore, the toluene in the reaction solution was removed by reduced pressure distillation to produce mesogen group-containing compound A.

[0055] [Table 1]

[0056] [Example of photocrosslinkable polymer production] Manufacturing Examples 1 to 8 For 100 parts by mass (phr) of the mesogen group-containing compound A produced in Comparative Example 1 and the mesogen group-containing ester compounds A to G produced in Examples 1 to 7, 1,5-pentamethylene diisocyanate (manufactured by Mitsui Chemicals, Inc., shown as "PDI" in Table 2) was used as an isocyanate compound, polycaprolactone polyol (manufactured by Daicel Corporation, product name "PCL-210N", shown as "PCL" in Table 2) or polypropylene glycol (manufactured by Asahi Glass Co., Ltd., shown as "PPG" in Table 2) was used as an active hydrogen group-containing compound, 2-hydroxyethyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., shown as "HOA" in Table 2) or 2-hydroxymethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd., shown as "methacrylate" in Table 2) was used as a photopolymerizable group-containing compound having an active hydrogen group, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (IGM A photocrosslinkable polymer composition was prepared by mixing 1,4-diazabicyclo[2.2.2]octane (manufactured by Tokyo Chemical Industry Co., Ltd., shown as "TPO" in Table 2) as a photosensitizer (manufactured by Tokyo Chemical Industry Co., Ltd., shown as "DABCO" in Table 2) in the amounts shown in Table 2. The raw materials were heated and melted while stirring at a temperature at which the mesogen group-containing compound used melts, specifically at ±30°C from the Ti of the mesogen group-containing compound or mesogen group-containing ester compound used, and the mesogen group-containing compound or mesogen group-containing ester compound was reacted with the isocyanate compound and the photopolymerizable group-containing compound to produce a photocrosslinkable polymer composition containing a photocrosslinkable polymer, a photoreaction initiator, and a photosensitizer. The resulting product was cooled and then pulverized with a plastic pulverizer (product name: ZI-420, manufactured by HORAI Co., Ltd.) to produce resin pellets of the photocrosslinkable polymer composition according to Production Examples 1 to 8.

[0057] [Table 2]

[0058] [Example of thermoresponsive polymer production] Manufacturing Examples 21-28 The resin pellets of the photocrosslinkable polymer composition produced in Production Examples 1 to 8 were fed into a single-screw extruder (product name: SZW25GT-24MG-STD, manufactured by Technovel Co., Ltd.) set at 80 to 150°C, and molded into a resin sheet having a thickness of 1.0 mm. The resin sheet was cooled by passing through a cooling roll set at 30 to 100°C, and taken up by a take-up roll. At this time, the resin sheet was stretched 1.5 to 10 times by providing a rotation difference between the cooling roll and the take-up roll. Furthermore, a tabletop UV curing device (product name: imini Grandage (ESC-1511U), manufactured by iGraphics Co., Ltd.) was installed between the cooling roll and the take-up roll, and the stretched resin sheet was irradiated with light from a high-pressure mercury lamp or a metal halide lamp as a light source to obtain a photocrosslinked (cured) thermoresponsive polymer.

[0059] [Table 3]

[0060] From the results in Table 3, it can be seen that the thermoresponsive polymers of the photocrosslinkable polymer compositions (Production Examples 22 to 28) obtained from the mesogen group-containing ester compounds of Examples 1 to 7 according to the present invention as raw materials have significantly higher breaking strength than the thermoresponsive polymer of the photocrosslinkable polymer composition (Production Example 21) obtained from the ether-based mesogen group-containing compound as raw material. It can also be seen that the thermoresponsive polymers of the photocrosslinkable polymer compositions (Production Examples 22 to 28) obtained from the mesogen group-containing ester compounds of Examples 1 to 7 according to the present invention as raw materials exhibit expansion and contraction behavior accompanying temperature changes.

Claims

1. A mesogen group-containing ester compound obtained by adding a carboxy group-containing compound or a lactone compound to a compound A having an active hydrogen group.

2. The compound A is represented by the following formula (1): 【Chemistry 1】 (In formula (1), X is an active hydrogen group, and R １ is a single bond which is a part of the adjacent bonding group, -N=N-, -CO-, -CO-O-, or -CH=N-, R ２ is a single bond that is part of the adjacent bonding group, or -O-; R ３ is a single bond that is a part of the adjacent bonding group, or an alkylene group having 1 to 20 carbon atoms. ２ is —O—, and R ３ The mesogenic group-containing ester compound according to claim 1 , which is a compound represented by the formula:

3. 2. The mesogen group-containing ester compound according to claim 1, wherein the proportion of ester bonds represented by the following formula is 5 to 30%. [0010] (In the above formula, the "average addition amount" indicates the average addition amount (mol) of the carboxy group-containing compound or the lactone compound per 1 mol of the compound A.)

4. 2. The mesogen group-containing ester compound according to claim 1, wherein the lactone compound is ε-caprolactone.

5. 5. The mesogenic group-containing ester compound according to claim 4, wherein the average amount of said ε-caprolactone added per mole of said compound A is 0.6 to 13 moles.

6. 2. The mesogen group-containing ester compound according to claim 1, wherein the carboxy group-containing compound is glycolic acid or lactic acid.

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