JP2018083901A - Curable composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition having excellent curability.SOLUTION: A curable composition contains a urethane prepolymer (A), which is a prepolymer having a group represented by the formula (1) as a terminal functional group, a thiol compound (B) which has two or more mercapto groups in one molecule, and a polymerization initiator (C), where, in the following formula (1), n is an integer of 1 or more and 3 or less, Ris a hydrogen atom or a methyl group, and * is a point for bonding to the rest of the molecule.SELECTED DRAWING: None

Description

  The present invention relates to a curable composition and a cured product thereof.

Various photocurable materials are known. For example, Patent Document 1 contains an ene oligomer having two or more ethylenically unsaturated groups and a number average molecular weight of 500 to 20,000, and a thiol compound having two or more mercapto groups in one molecule. An ene-thiol photocurable composition is disclosed.
Since the ene-thiol-based photocurable composition disclosed in Patent Document 1 contains an oligomer as one component, the viscosity is high. Therefore, operations such as coating, curing and molding are easy. Moreover, since the compounding rate of a thiol compound can be made low, there are few unpleasant odors.

  However, since the ene oligomer is an ester prepolymer oligomerized by an ester bond, it is necessary to increase the molecular weight in order to increase the viscosity of the ene-thiol photocurable composition. When the molecular weight is increased, the double bond equivalent is lowered, so that the curability of the ene-thiol-based photocurable composition is lowered. Moreover, when ester prepolymer was used, there existed a problem that the adhesive force of the hardened | cured material of an ene-thiol type photocurable composition was inadequate.

Patent Document 2 discloses an ene-thiol-based photocuring composed of a urethane prepolymer having a terminal functional group formed on at least one of an allyl ether group and a vinyl ether group, a polythiol having a mercapto group, and a tackifier. A sex composition is disclosed.
Since the ene-thiol-based photocurable composition disclosed in Patent Document 2 uses a urethane prepolymer, the operation of coating, curing, molding and the like is easy and the unpleasant odor is low, and the ester prepolymer It was possible to increase the viscosity without increasing the molecular weight as in the case of using and the adhesion of the cured product was sufficient.

  However, since the terminal functional group is an allyl ether group or a vinyl ether group, when the urethane prepolymer has a high molecular weight, the curability of the ene-thiol photocurable composition may be lowered. Therefore, for example, when a pigment is dispersed in an ene-thiol-based photocurable composition and used as a curable ink, there is a problem that the curability is insufficient.

International Publication No. 2014/203379 Japanese Patent Laying-Open No. 2015-205989

  Then, this invention makes it a subject to solve the trouble which the above prior arts have, and to provide the curable composition which has the outstanding sclerosis | hardenability, and its hardened | cured material.

In order to solve the above problems, one aspect of the present invention is as described in [1] to [12] below.
[1] A urethane prepolymer (A) which is a prepolymer having a group represented by the following formula (1) as a terminal functional group, a thiol compound (B) having two or more mercapto groups in one molecule, A curable composition containing a polymerization initiator (C).
However, n in the following formula (1) represents an integer of 1 to 3, and R ¹ represents a hydrogen atom or a methyl group. Further, * in the following formula (1) represents a bonding point to the rest of the molecule.

[2] The curable composition according to [1], wherein the urethane prepolymer (A) has two or more terminal functional groups in one molecule.
[3] The curable composition according to [1] or [2], wherein n in the formula (1) is 1.
[4] The ratio of the number of unsaturated groups of the urethane prepolymer (A) to the number of mercapto groups of the thiol compound (B) ([number of unsaturated groups] / [number of mercapto groups]) is 0. The curable composition according to any one of [1] to [3], which is within a range of 25 or more and 4 or less.

[5] The curable composition according to any one of [1] to [4], wherein the urethane prepolymer (A) measured by the Wiis method has an iodine value of 20 or more and 200 or less.
[6] The curable composition according to any one of [1] to [5], wherein the content of the thiol compound (B) is 25% by mass or less.

[7] The curable composition according to any one of [1] to [6], wherein the viscosity at 25 ° C. is from 5000 mPa · s to 10000000 mPa · s.
[8] At least a part of the thiol compound (B) has at least one of a secondary mercapto group and a tertiary mercapto group, and the secondary mercapto group and the tertiary mercapto group are combined in one molecule. The curable composition according to any one of [1] to [7], which has two or more.

[9] The thiol compound (B) includes 1,4-bis (3-mercaptobutyryloxy) butane, pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris (3-mercaptobutyloxy) Ethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione and at least one selected from trimethylolpropane tris (3-mercaptobutyrate) [1] to [7] The curable composition according to any one of [7].

[10] The curable composition according to any one of [1] to [9], further containing a radical reactive compound (D) that is a compound that can be cured by a radical reaction.
[11] The curable composition according to any one of [1] to [10], further containing a pigment (E).
[12] A cured product of the curable composition according to any one of [1] to [11].

  According to the present invention, it is possible to provide a curable composition having excellent curability and a cured product thereof.

One embodiment of the present invention will be described below. The curable composition of this embodiment has a urethane prepolymer (A) which is a prepolymer having a group represented by the following formula (1) as a terminal functional group, and two or more mercapto groups in one molecule. A thiol compound (B) and a polymerization initiator (C) are contained. However, n in the following formula (1) represents an integer of 1 to 3, and R ¹ represents a hydrogen atom or a methyl group. Further, * in the following formula (1) represents a bonding point to the rest of the molecule.

  Since the curable composition of this embodiment contains a urethane prepolymer (A) as one component, the viscosity is high and operations such as coating, curing and molding are easy. Moreover, since the compounding rate of a thiol compound (B) can be made low, there are few unpleasant odors. Furthermore, the viscosity can be increased without increasing the molecular weight as in the case of using an ester prepolymer, and the adhesiveness of the cured product is high.

  Moreover, since the urethane prepolymer (A) has the group represented by the above formula (1) as a terminal functional group, the urethane prepolymer (A) has a high molecular weight. Even so, the curability is excellent. Therefore, it is possible to design the curable composition to have a high viscosity using the high molecular weight urethane prepolymer (A).

  Furthermore, since the curable composition of this embodiment is a radical polymerization type ene-thiol-based curable composition, active thiyl radicals are regenerated even if radicals are deactivated by oxygen. Therefore, there is no polymerization inhibition by oxygen as seen in acrylic curable compositions, and the amount of polymerization initiator used can be reduced. In addition, the volumetric shrinkage during curing is small, and curing can be completed in a short time from a few seconds to several minutes from the start of polymerization, and a wide range of physical properties can be designed from hardened to flexible cured products. . Furthermore, if the viscosity of the curable composition is increased, a film-like cured product having a thickness of 1 mm or more can be produced, and the cured product can be formed into a sheet molded product.

  The curable composition of the present embodiment having such excellent performance is extremely useful as a curable material that is cured by light or heat, and can be used for various applications. For example, a curable ink can be obtained by dispersing a pigment in the curable composition of the present embodiment. Since the curable composition of the present embodiment is excellent in curability, even a highly concealed ink highly filled with pigments can be cured and used as a 3D printing ink with high design. You can also.

Below, the curable composition of this embodiment and the hardened | cured material obtained by hardening this curable composition with light or a heat | fever are demonstrated in detail.
[1] Urethane prepolymer (A) The urethane prepolymer (A) which is a prepolymer having the group represented by the above formula (1) as a terminal functional group is, for example, a hydroxyl group-containing compound having an unsaturated group. It is obtained by reacting with a monomer or prepolymer having a terminal isocyanato group. Monomers and polyisocyanates are listed as monomers having a terminal isocyanato group. Examples of the prepolymer having a terminal isocyanato group include a urethane prepolymer, an ester prepolymer, an ether prepolymer, or a thiolene compound having a terminal isocyanato group.

  From the viewpoint of curability, the number of terminal functional groups represented by the above formula (1) contained in one molecule of the urethane prepolymer (A) is preferably 1 or more and 6 or less, preferably 2 or more. Since it is more preferable, the compound (monomer or prepolymer having a terminal isocyanato group) used for the synthesis of the urethane prepolymer (A) preferably has two or more isocyanate groups in one molecule. The urethane prepolymer (A) may have an ethylenically unsaturated group other than the terminal functional group represented by the above formula (1), and the terminal functional group represented by the above formula (1) It is preferable from the viewpoint of curability that the total with other ethylenically unsaturated groups is 2 or more.

  Examples of the hydroxyl group-containing compound having an unsaturated group include 2-propenyl alcohol, 2-methyl-2-propenyl alcohol, 3-butenyl alcohol, 2-butenyl alcohol, 3-methyl-3-butenyl alcohol, and 4-pentenyl. Alcohol, 3-pentenyl alcohol, 4-methyl-4-pentenyl alcohol, etc. are mentioned. However, a hydroxyl group-containing compound having an unsaturated group at the end is preferable because of higher reactivity.

  N in the formula (1) is preferably 1. When n in the formula (1) is 1, the charge of the unsaturated bond is biased due to the high electron-withdrawing property of the carbonyl group of the urethane bond, so that the reactivity with the mercapto group of the thiol compound (B) becomes higher. Accordingly, 2-propenyl alcohol and 2-methyl-2-propenyl alcohol are more preferable as the hydroxyl group-containing compound having an alkenyl group, and either one or both can be used.

  What is employ | adopted as a raw material of a general urethane prepolymer can be used as polyisocyanate used for the synthesis | combination of a urethane prepolymer (A). For example, aromatic isocyanate, aliphatic isocyanate, alicyclic isocyanate, etc. are mentioned. Examples of the aromatic isocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethylene diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, 1,5-naphthalene diisocyanate, and the like. It is done. Examples of the aliphatic isocyanate include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isopropylene diisocyanate. Examples of the alicyclic isocyanate include o-hydrogenated xylene diisocyanate, m-hydrogenated xylene diisocyanate, p-hydrogenated xylene diisocyanate, methylene bis (cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1, 4-dimethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and the like. These polyisocyanates may be used individually by 1 type, and may be used in combination of 2 or more type.

  The urethane prepolymer having a terminal isocyanato group is, for example, a reaction product of a polyisocyanate and a polyol, and is obtained by reacting with an excess of polyisocyanate so that a terminal is an isocyanate group. Alternatively, a urethane prepolymer having a terminal isocyanato group can be obtained by reacting a polyisocyanate with both ends of a polyester polyol, polyether polyol, or polycarbonate polyol having a high molecular weight by an ester skeleton, an ether skeleton, or a carbonate skeleton. You can also.

  The polyol used for the synthesis of the urethane prepolymer whose terminal is an isocyanato group is a compound having two or more hydroxyl groups in one molecule, and it is possible to use what is adopted as a raw material for a general urethane prepolymer. it can. For example, 2,4-diethylpentanediol, 1,9-nonanediol, hydrogenated dimer diol, 2-butyl-2-ethylpropaneol, 2,2-dimethyl-1,3-propanediol, 1,2-propane Aliphatic alkanediols such as diols can be mentioned.

  Also, a propylene oxide adduct of methoxypolyethylene glycol bisphenol A, hydrogenated bisphenol A, 2,2- [4- (2-hydroxyethoxy) -3,5-dibromophenyl] propane, tricyclo [5.2.1.0 Alicyclic alkanediols such as decanedimethanol, 1,4-cyclohexanediol, and tris (2-hydroxyethyl) isocyanurate can also be mentioned as examples. Furthermore, aromatic alkanediols, polyols having a heterocyclic ring, polyester polyols, polyether polyols, polycarbonate polyols and the like can be given as examples.

  Examples of the polyester polyol include those obtained by ring-opening condensation of caprolactone, methylvalerolactone, and the like, and those obtained by a condensation reaction between a polyhydric alcohol and a polycarboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, butylene glycol, glycerin, trimethylolpropane and the like. These may be used alone or in combination of two or more. It may be used. Examples of the polyvalent carboxylic acid include glutaric acid, adipic acid, maleic acid, terephthalic acid, and isophthalic acid. These may be used alone or in combination of two or more. Good.

  Examples of polyether polyols include addition polymerization of oxides such as ethylene oxide, propylene oxide, trimethylene oxide, and butylene oxide to polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane, and sorbitol. Things.

  Examples of the polycarbonate polyol include polycarbonate diol derived from 1,6-hexanediol, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol, and 1,4-butanediol and 1,6. Polycarbonate diols derived from hexanediol, polycarbonate diols derived from 3-methyl-1,5-pentanediol and 1,6-hexanediol, polycarbonate diols derived from 1,4-cyclohexanedimethanol, 1, Examples include polycarbonate diols derived from 6-hexanediol and 1,4-cyclohexanedimethanol.

  Examples of the polyol include trivalent or higher polyhydric alcohols such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate, and the like. It is possible to use 1 type (s) or 2 or more types as a raw material of a urethane prepolymer (A).

  A catalyst may be used in the synthesis of the urethane prepolymer (A). What is used for a general urethane prepolymer can be used for a catalyst, For example, an amine catalyst, an organometallic catalyst, etc. are mentioned. Examples of the amine catalyst include triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, and the like. Examples of the organometallic catalyst include star octoate, dibutyltin dilaurate, lead octenoate, potassium octylate and the like. These various catalysts may be used individually by 1 type, and may be used in combination of 2 or more type.

  The thiolene compound having a terminal isocyanato group is a compound having an unsaturated bond and an isocyanato group in one molecule, such as 2-methacryloyloxyethyl isocyanate, 2 for a compound having one or more mercapto groups in one molecule. -It can obtain by carrying out Michael addition of acryloyloxyethyl isocyanate and 2-acryloyloxypropyl isocyanate.

  Since the urethane prepolymer (A) preferably has two or more terminal functional groups represented by the formula (1) in one molecule, the compound having one or more mercapto groups in one molecule includes the following: Polythiol can be preferably used. That is, aliphatic polythiol such as alkanedithiol having 2 to 20 carbon atoms, aromatic polythiol such as xylylene dithiol, polythiol obtained by substituting halogen atom of halohydrin adduct of alcohol with mercapto group, hydrogen sulfide of polyepoxide compound It is a polythiol composed of a reaction product. Alternatively, the following polythiols can also be preferably used. That is, it is a polythiol comprising an esterified product of a polyhydric alcohol having 2 to 6 hydroxy groups in the molecule and a thiocarboxylic acid typified by thioglycolic acid, β-mercaptopropionic acid, and β-mercaptobutanoic acid. . Michael addition can be reacted with a thermal polymerization initiator such as a peroxide or an azo compound or a photopolymerization initiator.

  If the viscosity of the urethane prepolymer (A) is too high, the fluidity of the curable composition will deteriorate, resulting in low productivity. If it is too low, the coating thickness when coating as a curable composition will be adjusted arbitrarily. It becomes difficult. In order to increase the viscosity of the urethane prepolymer (A), it is necessary to increase the average molecular weight, but in general, increasing the average molecular weight decreases the functional group concentration of the unsaturated bond group, thereby reducing the reactivity and curability. Affects. Since the urethane prepolymer (A) has a urethane bond, it has a higher viscosity than the ester prepolymer even if the average molecular weight is low. The average molecular weight of the urethane prepolymer (A) is preferably 500 or more and 18000 or less from the viewpoints of applicability and curability of the curable composition. In addition, an average molecular weight here shows the number average molecular weight of polystyrene conversion measured by gel permeation chromatography.

  Moreover, since urethane prepolymer (A) has a urethane bond, the adhesive force of the hardened | cured material of a curable composition becomes high compared with ester prepolymer. As an index of the adhesive strength of the cured product of the curable composition, it is possible to employ the adhesiveness evaluated by a cross cut test based on JIS K 5600. Specifically, after applying the curable composition to a plate made of SUS304 so as to have a film thickness of 50 μm and curing it, a cutter knife is used for the coating film made of a cured product of the curable composition. Make grid-like cuts that reach the substrate (SUS304 plate). In other words, 11 cuts are made in each of the vertical and horizontal intervals at intervals of 2 mm to produce 100 grids. Then, after the pressure-sensitive adhesive tape is strongly pressure-bonded to the cross-cut portion, the end portion of the pressure-sensitive adhesive tape is peeled off at an angle of 45 °, and the cross-cut state (the peeled state of the cured product) is evaluated in comparison with the standard drawing.

  When evaluated by this test, the adhesiveness of the cured product of the curable composition is preferably adhesiveness in the range of classification 0 to classification 2, and more preferably classification 0 or classification 1. In addition, classification 0 is a state in which there is no peeling in any of the grids of 100 grids, and classification 1 is that there is a small peeling of the coating film at the intersection of the cuts, and 5% of the grid has peeling. The state is as follows, and the classification 2 is a state in which there is peeling of the coating film along the line of the cut or at the crossing point of the cut, and the mesh of the grid with the peeling is over 5% and 15% or less.

  Since the urethane prepolymer (A) is blended according to the number of mercapto groups of the thiol compound (B), the higher the unsaturated bond concentration of the urethane prepolymer (A), the greater the blending amount of the thiol compound (B). Increases and the reactivity increases. The concentration of unsaturated bonds can be evaluated by the iodine value measured by the Wijs method. However, if the iodine value of the urethane prepolymer (A) is 20 or more and 200 or less, it can be cured even if the pigment is dispersed. The composition has high reactivity (curability).

Since the urethane prepolymer (A) has a terminal functional group represented by the formula (1), the curability can be maintained even if the iodine value is low. Therefore, there exists an advantage that an odor reduces by the part which the compounding quantity of a thiol compound (B) decreases. A more preferable iodine value is 20 or more and 65 or less, and both excellent curability and low odor can be achieved. Here, “excellent curability” means that curing is possible even when the concealability is high. The standard is as follows. That is, a curable composition to which a black pigment is added is formed into a film shape, and the film thickness is set so that the total light transmittance (average value of transmittance at a wavelength of 400 nm to 700 nm) is 1%. When it can harden | cure by exposing with the exposure amount of ² J / cm < ² > using a lamp | ramp, it is set as "the outstanding curability."

[2] About Thiol Compound (B) The thiol compound (B) that undergoes an enethiol reaction with the urethane prepolymer (A) is not particularly limited as long as it is a compound having two or more mercapto groups in one molecule. Specific examples include a compound having two mercapto groups in one molecule, a compound having three mercapto groups in one molecule, a compound having four mercapto groups in one molecule, and 6 in one molecule. And compounds having one mercapto group.

  Examples of compounds having two mercapto groups in one molecule are butanediol bis (2-mercaptoacetate), hexanediol bis (2-mercaptoacetate), ethanediol bis (2-mercaptoacetate), butanediol bis. (2-mercaptoacetate), 2,2 ′-(ethylenedithio) diethanethiol, ethylene glycol bis (3-mercapto-2-methylpropionate), propylene glycol bis (3-mercapto-2-methylpropionate) ), Diethylene glycol bis (3-mercapto-2-methylpropionate), butanediol bis (3-mercapto-2-methylpropionate), octanediol bis (3-mercapto-2-methylpropionate), bis (3-mercapto-2-methyl A compound having two primary mercapto groups in one molecule such as (propyl) phthalate, 1,4-bis (3-mercaptobutyryloxy) butane, bis (1-mercaptoethyl) phthalate, bis (2- Mercaptopropyl) phthalate, bis (3-mercaptobutyl) phthalate, ethylene glycol bis (3-mercaptobutyrate), propylene glycol bis (3-mercaptobutyrate), diethylene glycol bis (3-mercaptobutyrate), butanediol bis ( 3-mercaptobutyrate), octanediol bis (3-mercaptobutyrate), ethylene glycol bis (2-mercaptopropionate), propylene glycol bis (2-mercaptopropionate), diethylene glycol bis (2-mercaptopro) Onate), butanediol bis (2-mercaptopropionate), octanediol bis (2-mercaptopropionate), ethylene glycol bis (2-mercaptopropionate), propylene glycol bis (2-mercaptopropionate) , Diethylene glycol bis (2-mercaptopropionate), butanediol bis (2-mercaptopropionate), octanediol bis (2-mercaptopropionate), ethylene glycol bis (4-mercaptovalerate), propylene glycol bis (4-mercaptoisovalerate), diethylene glycol bis (4-mercaptovalerate), butanediol bis (4-mercaptovalerate), octanediol bis (4-mercaptovalerate), ethylene Glycol bis (3-mercaptovalerate), propylene glycol bis (3-mercaptovalerate), diethylene glycol bis (3-mercaptovalerate), butanediol bis (3-mercaptovalerate), octanediol bis (3-mercaptovalerate) A compound having two secondary mercapto groups in one molecule, such as ethylene glycol bis (2-mercaptoisobutyrate), propylene glycol bis (2-mercaptoisobutyrate), diethylene glycol bis (2- Examples include compounds having two tertiary mercapto groups in one molecule such as mercaptoisobutyrate), butanediol bis (2-mercaptoisobutyrate), octanediol bis (2-mercaptoisobutyrate), etc. Can do.

  Examples of a compound having three mercapto groups in one molecule include trimethylolpropane tris (2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (3- A compound having three primary mercapto groups in one molecule such as mercapto-2-methylpropionate), trimethylolpropane tris (3-mercaptobutyrate), trimethylolpropane tris (2-mercaptopropio) Nate), trimethylolpropane tris (2-mercaptopropionate), trimethylolpropane tris (4-mercaptovalerate), trimethylolpropane tris (3-mercaptovalerate), 1,3,5-tris (3- Mercaptobutyloxyethyl) -1 A compound having three secondary mercapto groups in one molecule such as 3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, or trimethylolpropane tris (2-mercaptoisobutyrate) And the like, etc., and the like having three tertiary mercapto groups in one molecule.

  Furthermore, examples of the compound having four mercapto groups in one molecule include four ones in one molecule such as pentaerythritol tetrakis (2-mercaptoacetate) and pentaerythritol tetrakis (3-mercaptopropionate). Compounds having a class mercapto group, dipentaerythritol hexakis (3-mercaptobutyrate), pentaerythritol tetrakis (2-mercaptopropionate), pentaerythritol tetrakis (3-mercapto-2-propionate), pentaerythritol tetrakis (4-mercaptovalerate), pentaerythritol tetrakis (3-mercaptovalerate), etc., compounds having four secondary mercapto groups in one molecule, pentaerythritol tetrakis (2-mercaptoisobutyrate) It can be mentioned chromatography vii) a compound having four tertiary mercapto groups in one molecule, such as and the like.

  Further, examples of compounds having 6 mercapto groups in one molecule include six primary mercapto groups in one molecule such as dipentaerythritol hexakis (3-mercapto-2-methylpropionate). Dipentaerythritol hexakis (3-mercaptobutyrate), dipentaerythritol hexakis (2-mercaptopropionate), dipentaerythritol hexakis (4-mercaptovalerate), dipentaerythritol hexakis A compound having six secondary mercapto groups in one molecule such as (3-mercaptovalerate) or 6 tertiary compounds of one molecule such as dipentaerythritol hexakis (2-mercaptoisobutyrate). The compound etc. which have a mercapto group can be mentioned.

  Among these thiol compounds (B), considering the odor, storage stability and pot life of the curable composition of the present embodiment, the number of secondary mercapto groups does not have a primary mercapto group. A compound in which the total number of tertiary mercapto groups is 2 or more is preferred. For example, a compound having two secondary mercapto groups in one molecule, a compound having two tertiary mercapto groups in one molecule, a compound having three secondary mercapto groups in one molecule, A compound having three tertiary mercapto groups in one molecule, a compound having four secondary mercapto groups in one molecule, a compound having four tertiary mercapto groups in one molecule, and one molecule A compound having 6 secondary mercapto groups in it, a compound having 6 tertiary mercapto groups in one molecule, and the like are preferable.

  As the thiol compound (B), in particular, 1,4-bis (3-mercaptobutyryloxy) butane, pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione and trimethylolpropane-tris (3-mercaptobutyrate) are more preferred.

  When all mercapto groups of the thiol compound (B) are bonded to secondary carbon atoms or tertiary carbon atoms (that is, all mercapto groups are secondary mercapto groups or tertiary mercapto groups) And), the curable composition has less unpleasant odor and is excellent in storage stability and pot life. If the storage stability of the curable composition is excellent, one-component curable composition can be obtained.

  A thiol compound (B) may be used individually by 1 type, and may use 2 or more types together. Moreover, although the molecular weight of a thiol compound (B) is not specifically limited, From a viewpoint of the sclerosis | hardenability improvement of the curable composition of this embodiment, it is preferable that it is 200 or more and 1000 or less.

  The thiol compound (B) can also be easily obtained as a commercial product. Among secondary thiols containing two or more mercapto groups in one molecule, those readily available as commercial products include 1,4-bis (3-mercaptobutyryloxy) butane (product of Showa Denko KK). Name Karenz MT (trademark) BD1), pentaerythritol tetrakis (3-mercaptobutyrate) (trade name Karenz MT (trademark) PE1 manufactured by Showa Denko KK), 1,3,5-tris (3-mercaptobutyryloxy) Ethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (trade name Karenz MT (trademark) NR1 manufactured by Showa Denko KK), trimethylolpropane tris (3-mercapto Butyrate) (trade name TPMB manufactured by Showa Denko KK) and the like.

  As described above, the blending amount of the urethane prepolymer (A) and the thiol compound (B) is determined based on the number of unsaturated groups of the urethane prepolymer (A) and the number of mercapto groups of the thiol compound (B). . Therefore, the preferable content of the thiol compound (B) in the curable composition of the present embodiment is represented by the ratio between the number of unsaturated groups of the urethane prepolymer (A) and the number of mercapto groups of the thiol compound (B). be able to.

  That is, the ratio of the number of unsaturated groups of the urethane prepolymer (A) to the number of mercapto groups of the thiol compound (B) ([number of unsaturated groups] / [number of mercapto groups]) is 0.25. It is preferably within the range of 4 or less. The content of the urethane prepolymer (A) and the thiol compound (B) in the curable composition may be determined so as to achieve such a ratio.

  Since the reaction between the unsaturated group and the mercapto group is equivalent, if the number of unsaturated groups is excessive with respect to the number of mercapto groups, radicals are easily generated by heat and the cured product may deteriorate. In addition, if the number of mercapto groups is excessive with respect to the number of unsaturated groups, the thiol compound (B) is liberated due to decomposition of the cured product by heat or moist heat, causing an unfavorable odor, There are many practical problems.

  For the same reason, the content of the thiol compound (B) is preferably 25% by mass or less, more preferably less than 25% by mass, and less than 20% by mass with respect to the total amount of the curable composition. More preferably. If content of the thiol compound (B) in a curable composition is in the said range, the cured | curing material excellent in practicality will be obtained as well as there are few odors before and behind hardening of a curable composition.

  In the present invention, the number of unsaturated groups of the urethane prepolymer (A) means the total number (molar number) of unsaturated groups of all the compounds belonging to the urethane prepolymer (A). The number of mercapto groups in the compound (B) means the total number (number of moles) of mercapto groups in all the compounds belonging to the thiol compound (B).

[3] Regarding the polymerization initiator (C) The polymerization initiator (C) includes a photopolymerization initiator and a thermal polymerization initiator. In the present invention, both are preferably radical polymerization initiators and active energy rays. Any compound may be used as long as it is a compound that generates radical polymerizable radicals by heat and accelerates the initiation of polymerization of the urethane prepolymer (A). For example, a polymerization initiator described in Japanese Patent No. 5302688 can be used. A polymerization initiator (C) may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

  The photopolymerization initiator and the thermal polymerization initiator may be used singly, but from the viewpoint that rapid curing is possible and the environmental load is small, the polymerization initiator (C) may contain a photopolymerization initiator. preferable. In addition, when performing superposition | polymerization which uses together hardening by irradiation of an active energy ray, and thermosetting, a photoinitiator and a thermal-polymerization initiator can be used together.

The type of the photopolymerization initiator is not particularly limited as long as it is a polymerization initiator that is sensitive to the irradiated active energy rays. Active energy rays include near-infrared rays, visible rays, ultraviolet rays, vacuum ultraviolet rays, X-rays, γ rays, electromagnetic waves such as electron rays, and particle rays.
As photopolymerization initiators sensitive to irradiation with visible light or ultraviolet light, acetophenones such as acetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one (for example, Darocur 1173 manufactured by BASF) Or the derivative | guide_body is mention | raise | lifted.

  Further, as a photopolymerization initiator sensitive to irradiation with visible light or ultraviolet light, benzophenone such as benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4-trimethylsilylbenzophenone, or Examples thereof include benzoin such as benzoin, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzoin isopropyl ether or derivatives thereof.

  Furthermore, methylphenylglyoxylate, benzoin dimethyl ketal, ethyl (2,4,6-trimethylbenzoyl) phenyl phosphinate (for example, Irgacure TPO manufactured by BASF) is used as a photopolymerization initiator sensitive to irradiation with visible light or ultraviolet light. -L), and bisacylphosphine oxide compounds such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -phenylphosphine oxide, Examples thereof include acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2,4,6-trimethoxybenzoyl-diphenylphosphine oxide.

  Particularly preferred photopolymerization initiators include diphenyl-2,4,6-trimethylbenzoylphosphine oxide, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-1- (4-isopropenylphenyl) -2-methyl. Propan-1-one and its oligomers, 2,4,6-trimethylbenzophenone, and a mixture thereof, LAMBERTI S.P. p. A. The product name “ESACURE KTO 46” manufactured by the company can be preferably used.

  Furthermore, bis (η5-2,4-cyclopentadien-1-yl) -bis [2,6-difluoro-3- (1H-pyrrole-1-) as a photopolymerization initiator sensitive to irradiation with visible light or ultraviolet light. Yl) phenyl] titanium, thioxanthones such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, methylphenylglyoxylate, benzoin dimethyl ketal, isoamyl p-dimethylaminobenzoate And ethyl p-dimethylaminobenzoate.

  A compound generally called a photopolymerization accelerator (for example, isoamyl p-dimethylaminobenzoate) having an excellent accelerating function with respect to a hydrogen abstraction type photopolymerization initiator (eg, benzophenone series, thioxanthone series). , Ethyl p-dimethylaminobenzoate) is also defined as being included in the photopolymerization initiator in the present invention.

  Among these photopolymerization initiators, acylphosphine oxide compounds, bisacylphosphine oxide compounds, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl 2-methylamino-1- (4-morpholinophenyl) butanone-1,2,2-dimethoxy-1,2-diphenylethane-1-one and 1-hydroxycyclohexyl phenyl ketone are preferred, and 2,4,6- Trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethoxybenzoyl-diphenylphosphine oxide, and 1-hydroxycyclohexyl phenyl ketone are more preferable.

  Next, the type of thermal polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. As the organic peroxide, for example, dialkyl peroxide, acyl peroxide, hydroperoxide, ketone peroxide, peroxy ester, and the like can be used. Specific examples thereof include diisobutyryl peroxide and cumyl peroxyneodecanoate. Examples of the azo compound include 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) and 2,2'-azobis (2,4-dimethylvaleronitrile).

  The content of the polymerization initiator (C) in the curable composition of the present embodiment contributes to the reaction of the polymerization initiator (C), the non-reactive solvent, the inorganic filler, the pigment and the like from the total amount of the curable composition. When the amount obtained by subtracting the content of the component not to be used is 100 parts by mass, it is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less. More preferably, it is 0.3 to 7 parts by mass, and particularly preferably 0.4 to 3 parts by mass. If content of a polymerization initiator (C) is in said numerical range, while being able to obtain sufficient hardening rate, the mechanical strength of hardened | cured material becomes high.

  For example, when the curable composition of this embodiment consists of a urethane prepolymer (A), a thiol compound (B), and a polymerization initiator (C), the urethane prepolymer (A) and the thiol compound (B) When the total content is 100 parts by mass, the content of the polymerization initiator (C) is preferably 0.01 parts by mass or more and 10 parts by mass or less.

  For example, when the curable composition of this embodiment consists of a urethane prepolymer (A), a thiol compound (B), a polymerization initiator (C), and a radical reactive compound (D) described later, urethane When the total content of the prepolymer (A), the thiol compound (B) and the radical reactive compound (D) is 100 parts by mass, the content of the polymerization initiator (C) is 0.01 parts by mass or more and 10 It is preferable that it is below mass parts.

[4] Radical Reactive Compound (D) The curable composition of the present embodiment may contain a radical reactive compound (D) for the purpose of improving various physical properties and adjusting the viscosity. The radical reactive compound (D) is a compound that can be cured by a radical reaction such as a radical polymerization reaction or a radical crosslinking reaction, and is a compound having an ethylenically unsaturated bond. These may be monomers or oligomers. Examples of the radical reactive compound (D) include a (meth) allyl group-containing compound (D-1) and a (meth) acryloyl group-containing compound (D-2).

  In the present specification, “(meth) allyl” means methallyl (ie, 2-methyl-2-propenyl) and / or allyl (ie, 2-propenyl). Further, “(meth) acrylate” means methacrylate and / or acrylate, and “(meth) acryl” means methacryl and / or acrylic.

The (meth) allyl group-containing compound (D-1) preferably has two or more (meth) allyl groups in one molecule, and is a compound having a number average molecular weight of 200 or more and 20000 or less from the viewpoint of viscosity. It is preferable.
As the (meth) allyl group-containing compound (D-1), a compound (D-1a) having at least one structure selected from an alicyclic structure, an aromatic ring structure, and a heterocyclic structure in the molecule, and an acyclic structure Compound (D-1b).

  Examples of the alicyclic structure include alicyclic rings having 3 to 6 carbon atoms, and a cyclohexane ring and a cycloheptane ring are preferable. Examples of the aromatic ring structure include an aromatic ring having 6 to 10 carbon atoms, and a benzene ring and a naphthalene ring are preferable. Examples of the heterocyclic structure include a three-membered ring to a ten-membered ring having a nitrogen atom, an oxygen atom, or a sulfur atom, and examples thereof include a pyridine ring, a triazine ring, a ring derived from cyanuric acid, and a ring derived from isocyanuric acid.

  When the (meth) allyl group-containing compound (D-1) is a monomer, examples of the compound (D-1a) include diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl trimellitic acid, and tetraallyl pyromellitic acid. Allyloxycarbonyl group-containing compounds having an aromatic ring structure such as diallyl 1,2-cyclohexanedicarboxylate diallyl, 1,3-cyclohexanedicarboxylate diallyl, 1,4-cyclohexanedicarboxylate diallyl, etc. Examples thereof include carbonyl group-containing compounds and N-allyl group-containing compounds having a heterocyclic structure such as triallyl isocyanurate and triallyl cyanurate.

  Examples of the compound (D-1a) include dimethallyl phthalate, dimethallyl isophthalate, dimethallyl terephthalate, trimethallyl trimellitic acid, tetramethallyl pyromellitic acid and the like, and 1,2-cyclohexane. Metallicyloxycarbonyl group-containing compounds having an alicyclic structure such as dimethallyl dicarboxylate, dimethallyl 1,3-cyclohexanedicarboxylate, dimethallyl 1,4-cyclohexanedicarboxylate, and N-methallyl groups such as trimethallyl isocyanurate and trimethallyl cyanurate Compounds.

Examples of the compound (D-1a) include allyl ether compounds such as bisphenol A diallyl ether and bisphenol A dimethallyl ether.
As the compound (D-1b), diethylene glycol bis (allyl carbonate), 1,2,3,4-butanetetracarboxylic acid tetraallyl, diallyl succinate, diallyl glutarate, diallyl adipate, diallyl sebacate, diallyl dimer, Hydrogenated dimer acid diallyl, diallyl 1,12-dodecanedioate, diallyl maleate, diallyl itaconate, diethylene glycol bis (methallyl carbonate), tetramethallyl 1,2,3,4-butanetetracarboxylate, dimethallyl succinate, glutar Dimethallyl acid, dimethallyl adipate, dimethallyl sebacate, dimethallyl dimer, dimethallyl hydrogenated dimer, dimethallyl 1,12-dodecanedioate, dimethallyl maleate, dimethallyl itaconate, trimethylolpropane dimethacrylate Ether, pentaerythritol methallyl ether, trimethylolpropane methallyl ether, pentaerythritol tetra methallyl ether can be exemplified.

When the (meth) allyl group-containing compound (D-1) is an oligomer, examples of the (meth) allyl group-containing compound (D-1) include (meth) allyl ester resins. The (meth) allyl ester resin is a compound having a (meth) allyloxycarbonyl group at the molecular end and a repeating unit in the molecule. For example, at least one selected from a transesterification reaction between a polybasic acid (meth) allyl ester compound and a polyhydric alcohol, a monool containing (meth) allyl allyl alcohol, a polyhydric alcohol and a polybasic acid, or a polybasic acid anhydride. Condensation reaction with seed, transesterification reaction between polyol having repeating unit and (meth) allyl ester compound of polybasic acid, and monool containing (meth) allylallyl alcohol, polyol having repeating unit and polybasic acid And a compound produced by various reactions of condensation reaction with at least one selected from polybasic acid anhydrides.
Specific examples of the (meth) allyl ester resin include, for example, oligomers having a structure represented by the following formulas (2), (3), and (5).

I R ² in the formula (2) each independently represents a linear alkylene group or a branched alkylene group having 1 to 36 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms). . R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group. Preferably, both R ³ and R ⁴ are hydrogen atoms.

  In the formula (2), (i + 1) Xs are each independently an organic group derived from a divalent carboxylic acid, preferably having an alkyl group having 1 to 4 carbon atoms as a substituent. It may be a phenylene group or a cyclohexylene group, more preferably a phenylene group or a cyclohexylene group having no substituent. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group.

The position at which the phenylene group or cyclohexylene group is bonded to the adjacent carbonyl carbon may be any of the 1,2-position, 1,3-position, and 1,4-position, but considering the ease of synthesis, the 1,3-position or 1-position , 4th position is preferred.
I in Formula (2) is an integer of 1 or more and 20 or less, preferably 1 or more and 18 or less, more preferably 1 or more and 15 or less. The molecular weight of the oligomer represented by the formula (2) is preferably 300 or more and 20000 or less, more preferably 800 or more and 18000 or less, and further preferably 1000 or more and 16000 or less.

  In formula (3), (2j + 1) A's are each independently an organic group derived from a divalent carboxylic acid, preferably having an alkyl group having 1 to 4 carbon atoms as a substituent. A good phenylene group or cyclohexylene group, more preferably a phenylene group or cyclohexylene group having no substituent. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group.

The position at which the phenylene group or cyclohexylene group is bonded to the adjacent carbonyl carbon may be any of the 1,2-position, 1,3-position, and 1,4-position, but considering the ease of synthesis, the 1,3-position or 1-position , 4th position is preferred.
J R ⁵ in the formula (3) each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec -Butyl group, isobutyl group, and tert-butyl group are included.) Or a group represented by the following formula (4). Moreover, R < ⁶ >, R < ⁸ > and j R < ⁷ > in Formula (3) show a hydrogen atom or a methyl group each independently. Preferably, R ⁶ , R ⁸ and j R ⁷ are all hydrogen atoms. A in Formula (4) is the same as that of the oligomer represented by Formula (3), and R ⁹ represents a hydrogen atom or a methyl group. Preferably, R ⁹ is a hydrogen atom.

  J in Formula (3) is an integer of 3 or more and 70 or less, preferably 4 or more and 60 or less, and more preferably 4 or more and 50 or less. The molecular weight of the oligomer represented by the formula (3) is preferably 300 or more and 20000 or less, more preferably 500 or more and 18000 or less, and further preferably 700 or more and 16000 or less.

  In formula (5), (q + 1) Z's are each independently an organic group derived from a divalent carboxylic acid, and preferably have an alkyl group having 1 to 4 carbon atoms as a substituent. A good phenylene group or cyclohexylene group, more preferably a phenylene group or cyclohexylene group having no substituent. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group.

[(P + 1) × q] R ¹⁰ in the formula (5) are each independently a linear alkylene group having 1 to 36 carbon atoms (preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms). Or a branched alkylene group is shown. Moreover, R < ¹¹ > and R < ¹² > in Formula (5) shows a hydrogen atom or a methyl group each independently. Preferably, both R ¹¹ and R ¹² are hydrogen atoms.

  P in Formula (5) is an integer of 1 or more and 10 or less, preferably 1 or more and 9 or less, more preferably 1 or more and 8 or less. Q in Formula (5) is an integer of 5 or more and 50 or less, preferably 5 or more and 45 or less, and more preferably 5 or more and 40 or less. The molecular weight of the oligomer represented by the formula (5) is preferably 300 or more and 20000 or less, more preferably 500 or more and 19000 or less, and further preferably 700 or more and 18000 or less.

Specific examples other than the (meth) allyl ester resin when the (meth) allyl group-containing compound (D-1) is an oligomer include polyene compounds derived from substituted or unsubstituted allyl alcohol, polyethylene glycol bis (allyl) Carbonate) and the like.
When the (meth) allyl group-containing compound (D-1) is a polymer, examples of the polymer skeleton include a polyethylene skeleton, a polyurethane skeleton, a polyester skeleton, a polyamide skeleton, a polyimide skeleton, a polyoxyalkylene skeleton, and a polyphenylene skeleton. .

Only one type of (meth) allyl group-containing compound (D-1) may be used alone, or two or more types may be used in combination.
The (meth) acryloyl group-containing compound (D-2) is not particularly limited as long as it is a compound containing a (meth) acryloyl group. Examples thereof include epoxy (meth) acrylate and (poly) ester. (Meth) acrylate, (poly) carbonate (meth) acrylate, hydrogenated polybutadiene (meth) acrylate, (poly) ether (meth) acrylate, (poly) urethane (meth) acrylate, and the like.

Among these, epoxy (meth) acrylate, (poly) ester (meth) acrylate, (poly) carbonate (meth) acrylate, and hydrogenated polybutadiene (meth) acrylate are preferable, and epoxy (meth) acrylate and (poly) carbonate ( (Meth) acrylate is more preferable, and epoxy (meth) acrylate is more preferable.
The (meth) acryloyl group-containing compound (D-2) is preferably a compound having two or more (meth) acryloyl groups from the viewpoint of curability.

  Epoxy (meth) acrylate means all compounds obtained by reacting an epoxy resin having an epoxy group with a monocarboxylic acid having a (meth) acryloyl group. The epoxy resin is preferably a compound having two or more epoxy groups in one molecule, specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin. Bisphenol type epoxy resins such as hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol S type epoxy resin, hydrogenated bisphenol AD type epoxy resin, and tetrabromobisphenol A type epoxy resin.

  Orthocresol novolac epoxy resin, phenol novolac epoxy resin, naphthol novolac epoxy resin, bisphenol A novolac epoxy resin, brominated phenol novolac epoxy resin, alkylphenol novolac epoxy resin, bisphenol S novolac epoxy resin, methoxy Examples also include novolak type epoxy resins such as group-containing novolak type epoxy resins and brominated phenol novolac type epoxy resins.

  Others are bifunctional such as phenol aralkyl type epoxy resin (commonly known as epoxidized xyloc resin), resorcin diglycidyl ether, hydroquinone diglycidyl ether, catechol diglycidyl ether, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, etc. Type epoxy resin, triglycidyl isocyanurate, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, biphenyl-modified novolak type epoxy resin (phenolic nucleus is linked by bismethylene group) Epoxidized polyhydric phenol resins), methoxy group-containing phenol aralkyl resins, and the like.

  Epoxy (meth) acrylate can also be easily obtained as a commercial item. Examples of commercially available epoxy (meth) acrylate include VR-77 manufactured by Showa Denko KK, Epoxy ester 40EM, Epoxy ester 30002M, Epoxy ester 3002A, Epoxy ester 3000MK, Epoxy ester 3000A manufactured by Kyoeisha Chemical Co., Ltd. , EBECRYL600, EBECRYL648, EBECRYL3700, etc. manufactured by Daicel Ornex Co., Ltd. can be mentioned.

Next, (poly) ester (meth) acrylate means a compound having at least one ester bond other than a (meth) acryloyloxy group and having at least one (meth) acrylate group.
(Poly) ester (meth) acrylate can also be easily obtained as a commercial item. Examples of commercially available (poly) ester (meth) acrylates include EBECRYL450, EBECRYL810, EBECRYL811, EBECRYL812, EBECRYL1830, EBECRYL846, EBECRYL851 and EBECRYL8551, EBECRYL851 and EBECRYL851. .

Next, (poly) carbonate (meth) acrylate means a compound having one or more carbonate groups and one or more (meth) acrylate groups.
Synthesis methods for (poly) carbonate (meth) acrylate include dehydrochlorination reaction between (meth) acrylic acid chloride and polycarbonate polyol, direct dehydration reaction between (meth) acrylic acid and (poly) carbonate polyol, ) Transesterification of a lower alkyl ester of acrylic acid and a (poly) carbonate polyol is used.

  (Poly) carbonate (meth) acrylate can also be easily obtained as a commercial product. Examples of the commercially available (poly) carbonate (meth) acrylate include compounds represented by the following formula (6) which is polycarbonate diol diacrylate manufactured by Ube Industries, Ltd. In the formula (6), k is an integer of 1 or more.

Next, hydrogenated polybutadiene (meth) acrylate means a compound having a hydrogenated polybutadiene structure and a (meth) acrylate structure in the molecule.
As a synthesis method of hydrogenated polybutadiene (meth) acrylate, esterification reaction of hydrogenated polybutadiene polyol and (meth) acrylic acid, transesterification reaction of hydrogenated polybutadiene polyol and (meth) acrylic acid ester, hydrogenated polybutadiene polyol and An addition reaction of isocyanato group-containing (meth) acrylate, an addition reaction of hydrogenated polybutadiene polyol, polyisocyanate, and alcoholic hydroxyl group-containing (meth) acrylate is preferably used.

  Hydrogenated polybutadiene (meth) acrylate can also be easily obtained as a commercial item. Examples of commercially available hydrogenated polybutadiene (meth) acrylates include, for example, NISSO-PB TEAI-1000 manufactured by Nippon Soda Co., Ltd., which is an adduct of hydrogenated polybutadiene polyol, polyisocyanate, and alcoholic hydroxyl group-containing acrylate, hydrogenated polybutadiene. Examples thereof include SPBDA-S30 manufactured by Osaka Organic Chemical Industry Co., Ltd., which is a diacrylate.

Among hydrogenated polybutadiene (meth) acrylates, esterified products of hydrogenated polybutadiene polyols having no urethane bond and (meth) acrylic acid, or transesterification products of hydrogenated polybutadiene polyol and (meth) acrylic esters Is preferred.
Next, (poly) ether (meth) acrylate means a compound having at least one ether bond and having at least one (meth) acrylate group in the molecule, such as polyethylene glycol diacrylate, polypropylene. Examples include glycol diacrylate and polytetramethylene glycol diacrylate.

  Next, (poly) urethane (meth) acrylate means a compound having one or more urethane bonds in the molecule and having one or more (meth) acrylate groups. For example, polyol, polyisocyanate and hydroxy A compound obtained by performing a polyaddition reaction using a group-containing (meth) acrylate as an essential raw material, or a compound obtained by performing a polyaddition reaction using a polyol and an isocyanate group-containing (meth) acrylate as an essential raw material Can be mentioned.

  When the curable composition of this embodiment contains a radical reactive compound (D), it is preferable that the content is as follows from a viewpoint of a viscosity and sclerosis | hardenability. That is, when the total content of the urethane prepolymer (A), the thiol compound (B) and the radical-reacted compound (D) is 100 parts by mass, the content of the radical-reactive compound (D) is 50 It is preferable to set it as mass parts or less, and it is more preferable to set it as 30 mass parts or less. When the content of the radical reactive compound (D) is within the above range, the effect of improving the mechanical properties of the cured product is sufficiently expressed while maintaining the viscosity and curability of the curable composition, and at the time of curing. Since the volumetric shrinkage of the resin is difficult to increase, the adhesion can be maintained.

[5] About Color Material The curable composition of the present embodiment may contain a color material such as a carbon material, a pigment, or a dye.
Examples of the carbon material include carbon black, acetylene black, lamp black, and graphite.

  Examples of the pigment include black pigments such as iron black, aniline black, cyanine black, and titanium black. However, the curable composition of the present embodiment may contain organic pigments such as red, green, and blue. For example, commercially available gel nail pigments and UV craft pigments may be used. Examples of such pigments include Pikaace coloring pigments (701, 731, 741, 755, 762) and transparent pigments (900 901, 910, 920, 921, 922, 924, 930, 932, 941, 942, 945, 947, 950, 955, 957, 960, 963, 968, 970, 980, 981, 982, 985) and the like. It is done.

  Examples of the dye include direct dyes, acid dyes, basic dyes, mordant dyes, acid mordant dyes, vat dyes, disperse dyes, reactive dyes, fluorescent whitening dyes, and plastic dyes. Examples of the plastic dye include KP PLAST (KP Plastic Red B, KP Plastic Blue GR, KP Plastic Yellow HK) manufactured by Kiwa Chemical Industry Co., Ltd., and the like. The dye means a substance having solubility in a solvent or compatibility with a resin and a property of coloring the dissolved or compatible substance.

  These color materials may be used singly or in combination of two or more, but it is preferable to contain the pigment (E) in the curable composition of the present embodiment. The content of the color material in the curable composition of the present embodiment is not particularly limited because the enethiol reaction between the urethane prepolymer (A) and the thiol compound (B) exhibits high curability, but the content of the color material is high. If it is too high, the viscosity of the curable composition may increase, and there may be problems such as the occurrence of color material aggregates. Therefore, the content of the color material in the curable composition is preferably 40% by mass or less.

[6] Viscosity of curable composition The curable composition of the present embodiment is applied on a substrate made of foam, nonwoven fabric, paper, polymer film, metal, wood, resin, etc., and the presence of air By irradiating ultraviolet rays or applying heat underneath, for example, a film-like cured product is obtained. When the curable composition is applied to the substrate, a coating device such as a comma coater, a die coater, or a gravure coater is used.

  In order to apply the curable composition to a desired film thickness, it is necessary to adjust the viscosity to an appropriate range, and the viscosity at 25 ° C. is preferably in the range of 5000 mPa · s to 10000000 mPa · s. More preferably, it is in the range of not less than 6000 mPa · s and not more than 100,000 mPa · s. If the viscosity of a curable composition is in the said range, since the fluidity | liquidity of a curable composition is favorable, the film thickness of predetermined | prescribed thickness is easy to be obtained. In addition, problems such as longer application time, higher discharge pressure by the application device, and contamination of the surroundings due to dripping are unlikely to occur.

  Since the curable composition of this embodiment contains a urethane prepolymer (A), the viscosity can be easily adjusted by controlling the temperature as compared with the case of containing an ester prepolymer. If the viscosity at 25 ° C. is 10000000 mPa · s or less, the curable composition can be normally applied using a coating apparatus by heating to 80 ° C. The viscosity is measured using a cone plate viscometer at a rotational speed at which the torque is 10% or more.

[7] Additives The curable composition of the present embodiment may contain a polymerization inhibitor as necessary in order to improve storage stability. The type of the polymerization inhibitor is not particularly limited, and examples thereof include 4-methoxy-1-naphthol, 1,4-dimethoxynaphthalene, 1,4-dihydroxynaphthalene, 4-methoxy-2-methyl-1-naphthol. 4-methoxy-3-methyl-1-naphthol, 1,4-dimethoxy-2-methylnaphthalene, 1,2-dihydroxynaphthalene, 1,2-dihydroxy-4-methoxynaphthalene, 1,3-dihydroxy-4- Methoxynaphthalene, 1,4-dihydroxy-2-methoxynaphthalene, 1,4-dimethoxy-2-naphthol, 1,4-dihydroxy-2-methylnaphthalene, pyrogallol, methylhydroquinone, tertiary butylhydroquinone, 4-methoxyphenol, N-nitroso-N-phenylhydroxyamine aluminium And the like. These polymerization inhibitors may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these polymerization inhibitors, methylhydroquinone, pyrogallol, and tertiary butylhydroquinone are particularly preferred from the viewpoint of storage stability of the curable composition containing the urethane prepolymer (A) and the thiol compound (B).
In addition, the content of the polymerization inhibitor is not particularly limited, but the component that does not contribute to the reaction such as the polymerization initiator (C), the non-reactive solvent, the inorganic filler, and the pigment from the total amount of the curable composition. When the amount obtained by subtracting the content of 100 parts by mass is less than 0.5 parts by mass, it is more preferably 0.0001 parts by mass or more and 0.2 parts by mass or less.

  The curable composition of the present embodiment may contain an antioxidant as necessary in order to suppress coloring of the cured product at a high temperature. The type of the antioxidant is not particularly limited. For example, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate], 4,6-bis (octylthiomethyl) -o-cresol, 2,4-bis [(dodecylthio) methyl] -6-methylphenol, 1,3, 5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine- , 4,6- (1H, 3H, 5H) -trione, tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) -trione, 4,4 ′, 4 ″-(1-methylpropanyl-3-ylidene) tris (6-tert-butyl-m-cresol), octadecyl-3- (3,5-di-tert -Butyl-4-hydroxyphenyl) propionate, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl}- 2,4,8,10-tetraoxaspiro [5.5] undecane, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxyphenylmethyl) -2,4,6-trimethylbenzene Zen and the like. These antioxidants may be used individually by 1 type, and may be used in combination of 2 or more type.

  Among these antioxidants, tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4 is used from the viewpoint of suppressing coloring of the cured product at a high temperature. , 6- (1H, 3H, 5H) -trione, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate are preferred.

  Further, the content of the antioxidant is not particularly limited, but the component that does not contribute to the reaction such as the polymerization initiator (C), the non-reactive solvent, the inorganic filler, and the pigment from the total amount of the curable composition. When the amount obtained by subtracting the content of 100 parts by mass is less than 0.5 parts by mass, it is more preferably 0.0001 parts by mass or more and 0.2 parts by mass or less.

  The curable composition of this embodiment may contain additives other than a polymerization inhibitor and an antioxidant as necessary in order to improve various properties. These additives may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios. Examples of additives other than the polymerization inhibitor and the antioxidant include the following (a) to (w).

(A) Thermoplastic resin (b) Deodorizer (c) Adhesion improver such as silane coupling agent and titanium coupling agent (d) UV absorption of benzophenones, benzotriazoles, salicylic acid esters, metal complex salts, etc. Agent

(E) Stabilizers such as metal soaps, inorganic salts or organic salts of heavy metals (eg, zinc, tin, lead, cadmium), organic tin compounds, etc. (f) Acetic acid, acrylic acid, palmitic acid, oleic acid, mercaptocarboxylic acid, etc. PH adjusters such as aliphatic carboxylic acids and aromatic organic acids such as phenol, naphthol, benzoic acid and salicylic acid

(G) Plasticizers such as phthalate ester, phosphate ester, fatty acid ester, epoxidized soybean oil, castor oil, liquid paraffin, alkyl polycyclic aromatic hydrocarbons (h) Paraffin wax, microcrystalline wax, polymer wax, beeswax , Waxes such as whale wax, low molecular weight polyolefin (i) Fillers such as acrylic resin powder and phenol resin powder

(J) Foaming agent (k) Dehydrating agents such as monoisocyanate compounds and carbodiimide compounds (l) Antistatic agents (m) Antibacterial agents (n) Antifungal agents

(O) Fragrance (p) Flame retardant (q) Leveling agent (r) Sensitizer (s) Antifoaming agent

  The curable composition of the present embodiment may contain other components other than those described above as long as the object of the present invention is not impaired. For example, the curable composition of the present embodiment may not contain a solvent or may contain a solvent, but preferably does not contain a solvent.

[8] About the preparation method of a curable composition The curable composition of this embodiment is a radical reactivity as needed with a urethane prepolymer (A), a thiol compound (B), and a polymerization initiator (C). The compound (D), pigment (E), polymerization inhibitor, antioxidant, other additives, and other components can be appropriately mixed and prepared.

  The preparation method of the curable composition of this embodiment is not specifically limited, Each raw material of curable compositions including a urethane prepolymer (A), a thiol compound (B), and a polymerization initiator (C) Any method can be used as long as it can be mixed and dispersed. Examples of the method of mixing and dispersing include the following methods.

(A) Each raw material is charged into a glass beaker, can, plastic cup, aluminum cup or the like and kneaded with a stir bar or spatula.
(B) Each raw material is kneaded with a double helical ribbon blade, a gate blade, or the like.
(C) Each raw material is kneaded with a planetary mixer.
(D) Each raw material is kneaded by a bead mill.
(E) Each raw material is kneaded with three rolls.
(F) Each raw material is kneaded by an extruder-type kneading extruder.
(G) Each raw material is kneaded by a rotating / revolving mixer.

The addition and mixing of each raw material can be performed in an arbitrary order, and all the raw materials may be added simultaneously or sequentially.
When the polymerization initiator (C) is used, treatments before curing such as handling and mixing of the above raw materials can be performed under conditions where the polymerization initiator (C) does not act before the curing treatment. For example, the processing before curing such as handling, mixing and the like of the above raw materials under active energy ray illumination or non-irradiation of active energy rays through a filter that removes light having an absorption wavelength that the photopolymerization initiator decomposes, or It can be performed at a temperature below the temperature at which the thermal polymerization initiator acts.

[9] Curing method of curable composition The curable composition of this embodiment is irradiated with active energy rays or heated to cure the curable composition and obtain a cured product. It is done. Examples of active energy rays used at the time of curing include ultraviolet rays, electron beams, and X-rays, but ultraviolet rays are preferable because inexpensive devices can be used.

  Various light sources can be used as the light source for curing the curable composition of the present embodiment with ultraviolet rays. Examples thereof include black light, UV-LED lamp, high pressure mercury lamp, pressurized mercury lamp, metal halide lamp, xenon lamp, and electrodeless discharge lamp.

  Here, the black light is a near-ultraviolet light having a wavelength of 300 nm to 430 nm (peak is around 350 nm) by applying a near-ultraviolet phosphor on a special outer tube glass cut from visible light and ultraviolet light having a wavelength of 300 nm or less. It is a lamp that radiates only. The UV-LED lamp is a lamp using a light emitting diode that emits ultraviolet rays. Among these light sources, a high-pressure mercury lamp and an LED lamp (UV-LED lamp) are preferable from the viewpoint of curability.

The irradiation amount of the active energy ray may be an amount sufficient to cure the curable composition of the present embodiment, and the composition, usage amount, thickness, and cured product to be formed of the curable composition of the present embodiment. The shape can be selected according to the shape. For example, when the coating film formed by applying the curable composition of the present embodiment is irradiated with ultraviolet rays, the exposure dose is preferably 0.2 J / cm ² or more and 5 J / cm ² or less, more preferably 1 J. / cm ² or more 3J / cm ² can be employed following exposure.

  The heating temperature (thermosetting temperature) for curing the curable composition by heating varies depending on the cleavage temperature of the thermal polymerization initiator used, but is preferably 80 ° C. or higher and 170 ° C. or lower. The heating time (thermal curing time) in the curing step by heating is the same, but is preferably 5 minutes or longer and 3 hours or shorter, more preferably 10 minutes or longer and 2 hours or shorter.

  The coating (coating) method in the case where the curable composition of the present embodiment is applied onto a substrate to form a coating film is not particularly limited. For example, in addition to spray method and dip method, natural coater, curtain flow coater, comma coater, gravure coater, micro gravure coater, die coater, curtain coater, kiss roll, squeeze roll, reverse roll, air blade, knife belt coater, floating knife , A method using a knife over roll, a knife on blanket or the like. In particular, since the temperature of the curable composition during coating can be adjusted and the viscosity can be adjusted, a method using a die coater is preferably employed.

By processing the curable composition of this embodiment into a sheet and curing it, a sheet-like cured product, that is, a sheet material is obtained. This sheet material may contain other components other than the cured product of the curable composition of the present embodiment, if necessary.
In addition, the thickness of the sheet material may be appropriately set according to the application, but the curable composition of the present embodiment can form a sheet material having a thickness of 1 mm or more even if it is photocured. .
In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. In addition, various changes or improvements can be added to the present embodiment, and forms to which such changes or improvements are added can also be included in the present invention.

  The present invention will be described more specifically with reference to the following examples and comparative examples. Various raw materials such as urethane prepolymer (A), thiol compound (B), polymerization initiator (C), radical reactive compound (D) are mixed, and the curability of Examples 1-5 and Comparative Examples 1-6. A composition was prepared. Various raw materials used for the preparation of the curable composition will be described below.

(1) Synthesis of Urethane Prepolymer (A) [Synthesis Example 1]: Synthesis of Urethane Prepolymer (A-1) In a 500 mL three-necked flask equipped with a distillation apparatus, Kuraray Polyol F-510 (Kuraray Co., Ltd.) was used as a polyol. 50 g (100 mmol) of 3-methyl-1,5-pentanediol and trimethylolpropane and adipic acid ester), and 105.1 g (500 mmol) of trimethylhexamethylene diisocyanate as a polyisocyanate are stirred under a nitrogen stream. While adding.

After confirming that the contents of the three-necked flask were uniform, 0.03 g of dioctylic acid dilaurate was further added as a catalyst. And it heated up slowly so that it might become 80-90 degreeC over 1 hour. Two hours after raising the temperature to the target temperature, Fourier transform infrared spectroscopic analysis of the contents of the three-necked flask was performed using an FT-IR spectroscopic analyzer, and a peak at 1050 cm ⁻¹ , which is the characteristic absorption position of the hydroxyl group, was found. It disappeared and it was confirmed that there was a peak at 2250 cm ⁻¹ , which is the characteristic absorption position of the isocyanato group.

Thereafter, 40.8 g (700 mmol) of 2-propenyl alcohol was slowly added dropwise to the contents of the three-necked flask as a hydroxyl group-containing compound having an unsaturated group, and reacted for 2 hours. Two hours later, Fourier transform infrared spectroscopic analysis was performed again, and it was confirmed that there was no peak at 2250 cm ⁻¹ , which is the characteristic absorption position of the isocyanato group, to obtain a urethane prepolymer (A-1). The number average molecular weight of the urethane prepolymer (A-1) was 930, and the iodine value was 91. Moreover, the quantity of the unsaturated group which a urethane prepolymer (A-1) has was 3.57 mmol / g.

[Synthesis Example 2]: Synthesis of Urethane Prepolymer (A-2) 100 g (200 mmol) of Kuraray Polyol P-510 (produced by Kuraray Co., Ltd., ester of 3-methyl-1,5-pentanediol and adipic acid) as a polyol The same procedure as in Synthesis Example 1 was carried out except that 105.1 g (500 mmol) of trimethylhexamethylene diisocyanate was used as the polyisocyanate, and 35 g (600 mmol) of 2-propenyl alcohol was used as the hydroxyl group-containing compound having an unsaturated group. A prepolymer (A-2) was synthesized. The number average molecular weight of the urethane prepolymer (A-2) was 1080, and the iodine value was 64. Moreover, the quantity of the unsaturated group which a urethane prepolymer (A-2) has was 2.51 mmol / g.

[Synthesis Example 3]: Synthesis of Urethane Prepolymer (A-3) As a polyol, Kuraray Polyol F-1010 (manufactured by Kuraray Co., Ltd., from 3-methyl-1,5-pentanediol, 1,9-nonanediol and adipic acid Synthesis Example) except that 147.3 g (143 mmol) of ester, 90.51 g (430 mmol) of trimethylhexamethylene diisocyanate as polyisocyanate, and 25 g (430 mmol) of 2-propenyl alcohol as a hydroxyl group-containing compound having an unsaturated group were used. The same operation as in No. 1 was performed to synthesize a urethane prepolymer (A-3). The number average molecular weight of the urethane prepolymer (A-3) was 2200, and the iodine value was 42. Moreover, the quantity of the unsaturated group which a urethane prepolymer (A-3) has was 1.64 mmol / g.

[Synthesis Example 4]: Synthesis of urethane prepolymer (A-4) 171.4 g (340 mmol) of Kuraray Polyol P-510 as a polyol, 108.6 g (420 mmol) of trimethylhexamethylene diisocyanate as a polyisocyanate, a hydroxyl group having an unsaturated group A urethane prepolymer (A-4) was synthesized in the same manner as in Synthesis Example 1 except that 20 g (340 mmol) of 2-propenyl alcohol was used as the containing compound. The number average molecular weight of the urethane prepolymer (A-4) was 2200, and the iodine value was 28. Moreover, the quantity of the unsaturated group which a urethane prepolymer (A-4) has was 1.13 mmol / g.

[Synthesis Example 5]: Synthesis of Urethane Prepolymer (A-5) In a 500 mL flask equipped with a Dean-Stark device and a condenser tube, Kuraray Polyol C-1015 (made by Kuraray Co., Ltd., diol component) 110 g (110 mmol) of 2-methyl-1,8-octanediol and 1,9-nonanediol with a number average molecular weight of 1000) 110 g and 3-mercaptobutanoic acid (manufactured by Showa Denko KK) which is a mercapto group-containing carboxylic acid 7 g (264 mmol), p-toluenesulfonic acid monohydrate (made by Tokyo Chemical Industry Co., Ltd.) 4.2 g (22 mmol) as a catalyst, and 130 g of toluene (made by Junsei Chemical Co., Ltd.) as a solvent were charged. .

  And after reducing the pressure in the reaction system to 73.3 kPa (550 mmHg), the contents were stirred while heating using an oil bath at 120 ° C. While removing the water produced by the reaction from the reaction system with a Dean-Stark apparatus, the mixture was heated and stirred for 4 hours and then allowed to cool to room temperature. The resulting reaction solution was neutralized with an aqueous sodium hydrogen carbonate solution having a concentration of 9% by mass. It was summed up. Further, the organic layer was washed three times with ion-exchanged water, and then the solvent (toluene) was distilled off from the organic layer by reducing the pressure using a vacuum pump to obtain 132.4 g (110 mmol) of a thiol prepolymer.

  There, 31.1 g (220 mmol) of 2-isocyanatoethyl acrylate (trade name Karenz AOI, manufactured by Showa Denko KK) and 2.5 g of hydroxycyclohexyl phenyl ketone (trade name IRGACURE 184, manufactured by BASF) as a photopolymerization initiator. With stirring, ultraviolet irradiation was performed at 250 W for 1 hour using an ultraviolet irradiation apparatus (SP-9 manufactured by USHIO INC.) To obtain 163 g of a thiolene compound having an isocyanato group at the end.

Thereto was added 0.03 g of dioctylic acid dilaurate and heated to 80 to 90 ° C. with stirring, and then 13 g (220 mmol) of 2-propenyl alcohol was slowly added dropwise as a hydroxyl group-containing compound having an unsaturated group. For 2 hours. Two hours later, using a FT-IR spectroscopic analyzer, it was confirmed that there was no peak at 2250 cm ⁻¹ , which is the characteristic absorption position of the isocyanato group, and a urethane prepolymer (A-5) was obtained. The number average molecular weight of the urethane prepolymer (A-5) was 1300, and the iodine value was 42. Moreover, the quantity of the unsaturated group which a urethane prepolymer (A-5) has was 1.67 mmol / g.

[Synthesis Example 6]: Synthesis of ester prepolymer (a-1) 300 g of diallyl terephthalate (manufactured by Tokyo Chemical Industry Co., Ltd.), 43 g of diethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.), propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) ) 31 g and dioctylic acid dilaurate 0.3 g were charged into a three-necked flask and heated in an oil bath adjusted to 180 ° C. to conduct a transesterification reaction. The reaction was carried out while gradually reducing the pressure from normal pressure to 1.4 kPa. When the theoretical amount of allyl alcohol was distilled off, the reaction was terminated, and an ester prepolymer (a-1) was obtained. The number average molecular weight of the ester prepolymer (a-1) was 1000, and the iodine value was 143. Moreover, the quantity of the unsaturated group which ester prepolymer (a-1) has was 5.65 mmol / g.

[Synthesis Example 7]: Synthesis of urethane prepolymer (a-2) As a polyol, Kuraray Polyol F-1010 (manufactured by Kuraray Co., Ltd., from 3-methyl-1,5-pentanediol, 1,9-nonanediol and adipic acid 147.3 g (143 mmol), 90.51 g (430 mmol) of trimethylhexamethylene diisocyanate as the polyisocyanate, and 50 g (430 mmol) of hydroxybutyl vinyl ether (manufactured by Nippon Carbide Corporation) as the hydroxyl group-containing compound having an unsaturated group. Except for the points described above, the same operation as in Synthesis Example 1 was performed to synthesize a urethane prepolymer (a-2) whose terminal was allyl ether. The number average molecular weight of the urethane prepolymer (a-2) whose terminal is allyl ether was 2300, and the iodine value was 41. Moreover, the quantity of the unsaturated group which a urethane prepolymer (a-2) has was 1.62 mmol / g.

Measurement of number average molecular weight and iodine value of urethane prepolymers (A-1) to (A-5), ester prepolymer (a-1), and urethane prepolymer (a-2) whose terminal is an allyl ether group. The method is as follows.
<Measurement method of number average molecular weight>
The number average molecular weights of the urethane prepolymers (A-1) to (A-5), the ester prepolymer (a-1), and the urethane prepolymer (a-2) whose terminal is an allyl ether group are determined by gel permeation chromatography. The measurement conditions measured are shown below.

Apparatus: Tosoh Corporation HLC-8320GPC built-in RI detector Column: Shodex LF-804 × 3 KF801 × 1 Eluent: Tetrahydrofuran Eluent flow rate: 1 mL / min Temperature: 40 ° C.
Sample concentration: 1% by mass

<Method for measuring iodine value>
The iodine value of urethane prepolymers (A-1) to (A-5), ester prepolymers (a-1), and urethane prepolymers (a-2) whose terminals are allyl ether groups are Hiranuma automatic titrator COM series. It was measured by. The measurement procedure is shown below.

1. Collect 1 g of sample in a 100 mL Erlenmeyer flask with a stopper and weigh accurately.
2. Add 20 mL of cyclohexane to dissolve the sample to obtain a sample solution.
3. Accurately add 25 mL of the Wiis solution to the sample solution, stopper, and stir in the dark for 30 minutes.
4). 20 mL of potassium iodide solution having a concentration of 1 mol / L and 100 mL of pure water are further added to the sample solution.
5. The electrode (platinum comparative composite electrode PR-733B) is immersed in the sample solution thus obtained, and titrated with a sodium thiosulfate standard solution having a concentration of 0.1 mol / L.
6). Above 1. ~ 5. A blank test is performed by performing a blank test according to the above procedure.

7). The iodine value (g / 100 g) is obtained by the following calculation formula.
Iodine value = {(BL-A1) × f × 1.269} / S
BL: Blank titration (mL)
A1: Titration volume of this test (mL)
f: Fighter of sodium thiosulfate standard solution with a concentration of 0.1 mol / L S: Mass of sample (g)
Note that 1.269 is 100 times the number of grams of iodine corresponding to 1 mL of a sodium thiosulfate solution having a concentration of 0.1 mol / L (for conversion per 100 g of sample).

(2) Preparation of curable composition and production of the cured product [Example 1]
67 parts by mass of the urethane prepolymer (A-1) obtained in Synthesis Example 1 as the urethane prepolymer (A) and pentaerythritol tetrakis (3) as the thiol compound (B) having two or more mercapto groups in one molecule -Mercaptobutanoic acid (33 parts by mass of Karenz MT (registered trademark) PE1 manufactured by Showa Denko KK) and 2 parts by mass of ESACURE KTO 46 (manufactured by LAMBERTI SpA) as a photopolymerization initiator (C) In a sealed plastic container having a capacity of 150 mL, and the mixture is stirred for 1 minute at a rotation speed of 2000 rpm in a stirring mode using a rotation revolution stirrer Awatori Nertaro ARE250 manufactured by Shinky Co., Ltd. -1) was obtained. The amount of mercapto group possessed by pentaerythritol tetrakis (3-mercaptobutanoic acid) is 7.14 mmol / g.

When mixing was completed, the lid of the sealed plastic container was opened, and the odor felt when the lid was opened was evaluated. And the odor of curable composition (X-1) was evaluated based on the following evaluation criteria. The results are shown in Table 1.
(Evaluation criteria)
A: Small odor
B: Odor but not uncomfortable
C: There is an unpleasant odor

  Next, the viscosity at 25.0 ° C. of the curable composition (X-1) obtained as described above was measured. The viscosity was measured using a cone plate viscometer manufactured by Brookfield. The spindle was SP-52, and the rotation speed was set so that the torque showed 10% or more. The results are shown in Table 1.

  Next, the applicability of the curable composition (X-1) obtained as described above was evaluated. While filling the curable composition (X-1) into a 10-mL polypropylene disposable syringe having a discharge port diameter of 2 mm, the curable composition (X-1) is discharged onto the glass substrate from the discharge port. The disposal syringe was moved to form a linear discharge on the glass substrate. And the applicability | paintability of curable composition (X-1) was evaluated by evaluating the shape of the discharge material on a glass substrate based on the following evaluation criteria. The results are shown in Table 1.

(Evaluation criteria)
A: The width of the discharged material was kept at 2 mm which is the diameter of the discharge port for 10 seconds or more after being discharged onto the glass substrate.
B: Although the width of the discharged material increases after discharging, the width after 10 seconds from discharging onto the glass substrate is 4 mm or less.
C: The width of the discharged material widens immediately after discharge, and the thickness cannot be maintained.
Next, the curable composition (X-1) obtained as described above was allowed to stand in an environment at a temperature of 60 ° C., and the change in viscosity with time was measured. And the storage stability of curable composition (X-1) was evaluated based on the following evaluation criteria. The results are shown in Table 1.

(Evaluation criteria)
A: Not thickened for more than 1 week
B: Does not thicken within 1 week
C: thickened within 1 day

Next, the curability of the curable composition (X-1) obtained as described above was evaluated. A 150 mm thick silicon sheet having a square opening with a side of 30 mm was placed on a glass substrate. The opening of the silicon sheet is filled with the curable composition (X-1), and light is used so that the integrated exposure becomes ² J / cm ² using a conveyor-type high-pressure mercury irradiator ECS-4001GX manufactured by Igraphic Co., Ltd. Irradiation was performed to cure the curable composition (X-1). The silicon sheet was removed 15 minutes after light irradiation, and the depth of the boundary between the cured part and the uncured part (cured depth) was measured. The results are shown in Table 1.

  Next, the curable composition (X-1) obtained as described above was applied in a film shape on a SUS304 substrate so as to have a thickness of 200 μm. Curing was performed under the same conditions. And the cross-cut test was done according to JISK5600, and the adhesiveness of the hardened | cured material of curable composition (X-1) was evaluated. The results are shown in Table 1. The evaluation of adhesion was performed based on the following evaluation criteria.

(Evaluation criteria)
Very good adhesion: Category 0 and Category 1
Adhesiveness: Category 2 and 3
Adhesion is inferior: Category 4 and Category 5

  In addition, classification 0 is a state in which there is no separation in any lattice eye of the 100 grids. Category 1 is a state in which there is a small peeling of the coating film at the intersection of the cuts, and the grid with peeling is 5% or less. Category 2 is a state in which there is peeling of the coating film along the line of the cut or at the intersection of the cuts, and the mesh of the grid with the peeling is over 5% and 15% or less.

  Classification 3 is a grid where the coating is largely or partially peeled along the incision line, and / or various portions of the grid are partially or completely peeled off. The eyes are over 15% and below 35%. Classification 4 indicates that the coating film is largely or partially peeled along the incision line, and / or the grid eyes of a plurality of places are partially or completely peeled off, The eye is in a state of exceeding 35% and not more than 65%. Category 5 is a state where there is a degree of separation that is not classified into categories 0 to 4.

  Next, the curable composition (X-1) obtained as described above was evaluated for curability in a composition having high concealability. 50 g of the curable composition (X-1) and 5 g of carbon black dispersion (carbon black concentration is 20% by mass) are put in a 150 mL sealed plastic container, and a rotating and rotating stirrer made by Shinkey Co., Ltd. Using Neritaro (trademark) ARE250, the mixture was stirred for 1 minute in a stirring mode at a rotation speed of 2000 rpm and mixed. Then, the mixture was applied on a SUS304 substrate in a film form so as to have a thickness of 50 μm, cured under the same conditions as in the case of the above-described evaluation of curability, and then touched. The curability of the curable composition (X-1) having a concealing composition was evaluated based on various evaluation criteria.

(Evaluation criteria)
A: There is no tack and no fingerprint marks are formed on the surface of the cured product.
B: The surface of the cured product is soft and has fingerprint marks. Alternatively, the cured product undulates because the internal curability and the surface curability are different.
C: Uncured material adheres to fingers

  The carbon black dispersion was prepared as follows. Carbon black (Degussa Special Black 250) 20 g, dispersant (Ajinomoto Fine Techno Co., Ltd. Ajisper 822) 1 g, and 1,6-hexanediol diacrylate 79 g were mixed and then premixed with a disperser. To obtain a mixed solution. And carbon black in a liquid mixture was further disperse | distributed using the continuous annular type bead mill (brand name spike mill type | model SHG-4 by Inoue Seisakusho Co., Ltd.), and the carbon black dispersion liquid was obtained.

  The beads used in the continuous annular bead mill were zirconia beads having a diameter of 0.65 mm, and the bead filling rate in the vessel was 80% by volume. The peripheral speed of the rotor was set to 12 m / second, the discharge amount of the carbon black dispersion was 1 liter / minute, and the temperature was set to about 30 ° C. The residence time in the vessel of the carbon black dispersion was 6 minutes (running time 1 hour).

[Examples 2 to 5 and Comparative Examples 1 to 6]
Except the point which changed the kind and usage-amount of each raw material as shown in Table 1, operation similar to Example 1 is performed, and curable composition (X-2)-(X-11) and those hardening | curing I got a thing. And it carried out similarly to Example 1, and evaluated curable composition (X-2)-(X-11) and those hardened | cured materials. The results are shown in Table 1.

  In addition, “urethane acrylate” described in Table 1 is urethane acrylate EBECRYL8804 manufactured by Daicel Ornex Co., Ltd. “DAIP” shown in Table 1 is diallyl isophthalate, the iodine value thereof is 203, and the amount of unsaturated groups possessed by DAIP is 7.9 mmol / g. Furthermore, “PETP” described in Table 1 is pentaerythritol tetrakis (3-mercaptopropionate) PETP manufactured by Sakai Chemical Co., Ltd., and the amount of mercapto groups possessed by PETP is 8.13 mmol / g. Furthermore, “DPHA” described in Table 1 is dipentaerythritol hexaacrylate DPHA manufactured by Daicel Ornex Co., Ltd.

  As can be seen from the results shown in Table 1, Examples 1 to 1 containing a urethane prepolymer (A) having a terminal functional group represented by the formula (1), a thiol compound (B), and a polymerization initiator (C). The curable compositions (X-1) to (X-5) of Example 5 had good applicability and storage stability in addition to low odor. Further, the curability with a composition having high curing depth, adhesion, and concealment was excellent.

On the other hand, Comparative Example 1 using allyl monomer DAIP having no urethane bond instead of urethane prepolymer (A) is excellent in odor, storage stability and curability, but is applied because of low viscosity. The adhesiveness was poor and the adhesion was low.
In Comparative Example 2 in which the ester prepolymer (a-1) having no urethane bond is used in place of the urethane prepolymer (A), there is no problem in odor, storage stability, and curing depth, but the viscosity is low. The applicability was poor and the adhesion was also poor.

  Comparative Example 3 having a urethane bond but having a terminal functional group that is an allyl ether group instead of the urethane prepolymer (A) has good coatability and adhesion, Curability with a composition with high concealment was poor. Moreover, since the comparative example 3 used the primary thiol compound PETP, it resulted in inferior storage stability.

In Comparative Example 4 in which a urethane prepolymer having a urethane bond but having a terminal functional group of an acryloyl group in place of the urethane prepolymer (A) was used, the coatability and adhesion were good, but the curability was poor. Moreover, since the comparative example 4 used the primary thiol compound PETP, it resulted in inferior storage stability.
Comparative Example 5 containing no thiol compound (B) and Comparative Example 6 using a thiol compound (3-mercaptobutanoic acid) having one mercapto group in one molecule had very poor curability.

Claims (12)

Urethane prepolymer (A) which is a prepolymer having a group represented by the following formula (1) as a terminal functional group, a thiol compound (B) having two or more mercapto groups in one molecule, and a polymerization initiator A curable composition containing (C).
However, n in the following formula (1) represents an integer of 1 to 3, and R ¹ represents a hydrogen atom or a methyl group. Further, * in the following formula (1) represents a bonding point to the rest of the molecule.

  The curable composition according to claim 1, wherein the urethane prepolymer (A) has two or more terminal functional groups in one molecule.   The curable composition according to claim 1 or 2, wherein n in the formula (1) is 1.   The ratio of the number of unsaturated groups of the urethane prepolymer (A) to the number of mercapto groups of the thiol compound (B) ([number of unsaturated groups] / [number of mercapto groups]) is 0.25 or more. It is in the range of 4 or less, The curable composition as described in any one of Claims 1-3.   The curable composition according to any one of claims 1 to 4, wherein the urethane prepolymer (A) measured by the Wiis method has an iodine value of 20 or more and 200 or less.   Content of the said thiol compound (B) is 25 mass% or less, The curable composition as described in any one of Claims 1-5.   The curable composition according to any one of claims 1 to 6, which has a viscosity at 25 ° C of from 5000 mPa · s to 10000000 mPa · s.   At least a part of the thiol compound (B) has at least one of a secondary mercapto group and a tertiary mercapto group, and a total of two or more secondary mercapto groups and tertiary mercapto groups in one molecule. The curable composition according to any one of claims 1 to 7.   The thiol compound (B) is 1,4-bis (3-mercaptobutyryloxy) butane, pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris (3-mercaptobutyloxyethyl)- 8. The method according to claim 1, comprising at least one selected from 1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione and trimethylolpropane tris (3-mercaptobutyrate). The curable composition as described in any one.   The curable composition as described in any one of Claims 1-9 which further contains the radical reactive compound (D) which is a compound which can be hardened | cured by radical reaction.   The curable composition according to any one of claims 1 to 10, further comprising a pigment (E).   Hardened | cured material of the curable composition as described in any one of Claims 1-11.