Method for producing urethane bond-containing compound

Abstract

To provide a production method that allows a urethane reaction to occur with excellent reactivity, productivity, and environmental hygiene without using organic tin compounds, thereby producing a urethane bond-containing compound.SOLUTION: A method for producing a urethane bond-containing compound includes causing the reaction between a hydroxy group-containing compound (A) and an isocyanate group-containing compound (B) to occur in the presence of a bismuth compound (α) to produce a urethane bond-containing compound, in which a moisture content in the reaction system is set to 700 ppm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a urethane bond-containing compound, and more particularly to a method for producing a urethane bond-containing compound which is excellent in reactivity, productivity, and environmental hygiene without using an organotin compound. [Background technology]

[0002] Conventionally, active energy ray-curable resin compositions have been widely used as coating agents for various substrates, adhesives, pressure-sensitive adhesives, etc., because they can be cured completely by irradiation with energy rays for a very short period of time. Urethane (meth)acrylate compounds are well known as components constituting such active energy ray-curable resin compositions.

[0003] In producing such urethane (meth)acrylate compounds, organotin compounds such as dibutyltin dilaurate, which can improve the reaction rate, are generally used as catalysts for the urethane reaction.

[0004] However, there are concerns that organotin compounds may have an effect on living organisms as endocrine disruptors. In addition, in recent years, with the trend toward high-precision components, particularly in the electrical and electronics fields, contamination of products due to bleed-out and outgassing of organotin compounds has become a problem, and manufacturing methods that do not use organotin compounds are being investigated.

[0005] As a catalyst to replace such organotin compounds, for example, Patent Document 1 proposes using a bismuth compound as a catalyst to react a compound containing a terminal isocyanate group with a (meth)acrylate compound containing a hydroxyl group. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-45362 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when using the manufacturing method disclosed in Patent Document 1 to produce a urethane (meth)acrylate, for example, by reacting a hydroxyl group-containing (meth)acrylate (such as dipentaerythritol pentaacrylate) with a diisocyanate compound (such as isophorone diisocyanate), the reaction of the organobismuth compound is slower than that of the organotin compound, and therefore it is necessary to use a larger amount of the organobismuth compound than the organotin compound. Furthermore, there is a concern that using a large amount of the organobismuth compound may cause the resulting urethane (meth)acrylate to become cloudy, resulting in poor appearance.

[0008] Under these circumstances, an object of the present invention is to provide a production method for obtaining a urethane bond-containing compound by which a urethane reaction can be carried out without using an organotin compound, with excellent reactivity, productivity, and environmental hygiene. [Means for solving the problem]

[0009] However, in light of these circumstances, the present inventors have conducted extensive research and have focused on bismuth compounds as catalysts that can replace organotin compounds, and have discovered that the amount of water in the reaction system in a urethane reaction has a significant effect on the reaction.

[0010] In other words, in a urethane reaction using a bismuth-based compound as a catalyst, the bismuth-based compound is hydrolyzed by moisture in the reaction system, which deactivates the catalytic function and reduces reactivity. In addition, when additional catalyst is added to advance the reaction, by-products such as bismuth hydroxide are produced, causing the reaction to become cloudy. These problems make it difficult to obtain a urethane bond-containing compound with good productivity. However, in the present invention, the inventors have found that by reducing the amount of moisture in the reaction system when using a bismuth-based compound as a catalyst in the urethane reaction of a hydroxyl group-containing compound and an isocyanate group-containing compound, a urethane reaction with excellent reactivity, productivity, and environmental hygiene can be carried out without using an organotin compound, and have completed the present invention.

[0011] That is, the gist of the present invention relates to a method for producing a urethane bond-containing compound, characterized in that when a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B) are reacted in the presence of a bismuth compound (α) to produce a urethane bond-containing compound, the water content in the reaction system is kept at 700 ppm or less. [Effects of the Invention]

[0012] According to the production method of the present invention, a urethane reaction can be carried out with excellent reactivity, productivity, and environmental hygiene without using an organotin compound, and a urethane bond-containing compound can be obtained. Among the urethane bond-containing compounds, for example, a urethane (meth)acrylate-based compound is useful as a raw material for an active energy ray-curable resin composition, and can be used for various applications such as a coating agent, an adhesive, and a pressure-sensitive adhesive. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below. In the present invention, (meth)acrylic means acrylic or methacrylic, (meth)acryloyl means acryloyl or methacryloyl, and (meth)acrylate means acrylate or methacrylate, respectively.

[0014] The method for producing a urethane bond-containing compound of the present invention comprises reacting a hydroxyl group-containing compound (A) with an isocyanate group-containing compound (B) in the presence of a bismuth compound (α), and adjusting the water content in the reaction system to 700 ppm or less. First, the components (A), (B), and (α) will be described.

[0015] The hydroxyl group-containing compound (A) used in the present invention may be any compound having a hydroxyl group that reacts with the isocyanate group of the isocyanate group-containing compound (B), and examples thereof include hydroxyl group-containing (meth)acrylates (a1), polyols (a2), monools (a3), etc. Among these, the hydroxyl group-containing compound (A) is preferably at least one selected from the hydroxyl group-containing (meth)acrylates (a1) and polyols (a2), since it can produce the urethane (meth)acrylate-based compound (UA) described below, which is a raw material for active energy ray-curable resin compositions useful for applications such as coating agents, adhesives, and pressure-sensitive adhesives.

[0016] The hydroxyl group-containing (meth)acrylate (a1) is a compound having a hydroxyl group and a (meth)acryloyl group, and preferably has 1 to 5 hydroxyl groups, particularly preferably one hydroxyl group.

[0017] Examples of the hydroxyl group-containing (meth)acrylate (a1) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethyl acryloyl phosphate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, dipropylene glycol mono(meth)acrylate, fatty acid-modified glycidyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and 2-hydroxy-3-(meth)acryloyl hydroxyl group-containing (meth)acrylates containing one ethylenically unsaturated group, such as acryloyloxypropyl (meth)acrylate; hydroxyl group-containing (meth)acrylates containing two ethylenically unsaturated groups, such as glycerin di(meth)acrylate and 2-hydroxy-3-acryloyl-oxypropyl methacrylate; and hydroxyl group-containing (meth)acrylates containing three or more ethylenically unsaturated groups, such as pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, ethylene oxide-modified pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol penta(meth)acrylate, and ethylene oxide-modified dipentaerythritol penta(meth)acrylate. These can be used alone or in combination of two or more.

[0018] Among these, for coating agent applications (hard), hydroxyl group-containing (meth)acrylates containing three or more ethylenically unsaturated groups are preferred, and for adhesive applications (soft), hydroxyl group-containing (meth)acrylates containing three or less ethylenically unsaturated groups are preferred.

[0019] The polyol (a2) may be any compound having two or more hydroxyl groups (excluding the hydroxyl group-containing (meth)acrylate (a1)).

[0020] Examples of the polyol (a2) include aliphatic polyols, alicyclic polyols, polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols, polyisoprene polyols, (meth)acrylic polyols, and polysiloxane polyols.

[0021] Examples of the aliphatic polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, dimethylolpropane, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, 1 Examples of suitable hydroxyl groups include aliphatic alcohols containing two hydroxyl groups such as 1,6-hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, pentaerythritol diacrylate, 1,9-nonanediol, and 2-methyl-1,8-octanediol; sugar alcohols such as xylitol and sorbitol; and aliphatic alcohols containing three or more hydroxyl groups such as glycerin, trimethylolpropane, and trimethylolethane.

[0022] Examples of the alicyclic polyol include cyclohexanediols such as 1,4-cyclohexanediol and cyclohexyldimethanol, hydrogenated bisphenols such as hydrogenated bisphenol A, and tricyclodecane dimethanol.

[0023] Examples of polyether polyols include alkylene structure-containing polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polypentamethylene glycol, and polyhexamethylene glycol, and random or block copolymers of these polyalkylene glycols.

[0024] Examples of polyester-based polyols include condensation polymers of polyhydric alcohols and polycarboxylic acids, ring-opening polymers of cyclic esters (lactones), and reaction products of three components: polyhydric alcohols, polycarboxylic acids, and cyclic esters.

[0025] Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylene diol, 1,3-tetramethylene diol, 2-methyl-1,3-trimethylene diol, 1,5-pentamethylene diol, neopentyl glycol, 1,6-hexamethylene diol, 3-methyl-1,5-pentamethylene diol, 2,4-diethyl-1,5-pentamethylene diol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), bisphenols (such as bisphenol A), and sugar alcohols (such as xylitol and sorbitol).

[0026] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, and trimellitic acid.

[0027] Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone.

[0028] Examples of the polycarbonate polyol include a reaction product of a polyhydric alcohol with phosgene, and a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate).

[0029] Examples of the polyhydric alcohol include the polyhydric alcohols exemplified in the description of the polyester polyol, and examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, and hexamethylene carbonate.

[0030] The polycarbonate polyol may be any compound having a carbonate bond in the molecule and a hydroxyl group at the end, and may have an ester bond in addition to the carbonate bond.

[0031] The polyolefin polyols include those having a homopolymer or copolymer of ethylene, propylene, butene, or the like as a saturated hydrocarbon skeleton and having hydroxyl groups at the molecular terminals.

[0032] The polybutadiene-based polyols include those having a butadiene copolymer as a hydrocarbon skeleton and having hydroxyl groups at the molecular terminals. The polybutadiene polyol may be a hydrogenated polybutadiene polyol in which all or part of the ethylenically unsaturated groups contained in the structure thereof have been hydrogenated.

[0033] The polyisoprene-based polyols include those having an isoprene copolymer as a hydrocarbon skeleton and having hydroxyl groups at the molecular terminals. The polyisoprene-based polyol may be a hydrogenated polyisoprene polyol in which all or part of the ethylenically unsaturated groups contained in the structure thereof have been hydrogenated.

[0034] The (meth)acrylic polyols include those having at least two hydroxyl groups in the molecule of an alkyl (meth)acrylate polymer or copolymer, and examples of such alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate.

[0035] Examples of the polysiloxane polyol include dimethylpolysiloxane polyol and methylphenylpolysiloxane polyol.

[0036] The polyol compounds (a2) can be used singly or in combination of two or more.

[0037] In the present invention, the number average molecular weight of the polyol (a2) is usually 100 to 6000, and from the viewpoint of handleability, it is preferably 150 to 5000, and particularly preferably 200 to 4500. If the number average molecular weight is too small, the polyol (a2) tends to crystallize easily, whereas if the number average molecular weight is too large, the polyol (a2) tends to have a high molecular weight and a high viscosity.

[0038] The number-average molecular weights mentioned above are number-average molecular weights converted into standard polystyrene molecular weights. The samples were analyzed using high-performance liquid chromatography (manufactured by Japan Waters, "Waters 2695 (main unit)" and "Waters 2414 (detector)") with a Shodex GPC KF-806L column (exclusion limit molecular weight: 2 × 10 7 Separation range: 100 to 2 × 10 7 The measurement is performed using three columns in series (theoretical plate number: 10,000 columns / column, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm).

[0039] The isocyanate group-containing compound (B) used in the present invention may be any compound having an isocyanate group, and examples thereof include monoisocyanates having one isocyanate group and polyisocyanates (b1) having two or more isocyanates. Among these, polyisocyanates (b1) having two or more isocyanates are preferred because various physical properties can be obtained by oligomerization or high molecular weight. The upper limit of the number of isocyanate groups is usually 6, preferably 3.

[0040] Examples of the polyisocyanate (b1) include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of the polyisocyanate include aliphatic polyisocyanates such as methylisocyanate, lysine diisocyanate, and lysine triisocyanate; alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and norbornene diisocyanate; trimer compounds or polymer compounds of these polyisocyanates; allophanate polyisocyanates; biuret polyisocyanates; and water-dispersible polyisocyanates.

[0041] Among these, diisocyanates are preferred from the viewpoint of stability during the urethanization reaction, and particularly preferred are aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate, and alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane, and more preferably are isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate and norbornene diisocyanate from the viewpoint of small cure shrinkage, and particularly preferred are hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate and isophorone diisocyanate from the viewpoint of excellent reactivity and versatility. The above isocyanate group-containing compounds (B) can be used alone or in combination of two or more.

[0042] In the present invention, the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B) are reacted in the presence of the bismuth compound (α), which functions as a catalyst for the urethane reaction.

[0043] Examples of the bismuth compound (α) include bismuth nitrate, bismuth bromide, bismuth iodide, and bismuth sulfide, as well as organic bismuth compounds such as dibutyl bismuth dilaurate, dioctyl bismuth dilaurate, and organic acid bismuth salts such as bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, bismuth laurate, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, and bismuth digallate. Among these, organic bismuth compounds, more preferably organic acid bismuth salts, are particularly preferred in terms of reactivity.

[0044] When using the catalyst, it is preferred to use it as a mixture of an organic acid bismuth salt and an organic acid. Such organic acids include, for example, 2-ethylhexanoic acid, and from the viewpoint of handling, it is preferable that the organic acid is the same as the organic acid that forms the organic acid bismuth salt.

[0045] In the present invention, the amount of the bismuth compound (α) used is preferably 0.001 to 0.02% by weight, particularly 0.002 to 0.02% by weight, and even more preferably 0.002 to 0.015% by weight, based on the total amount of the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B). If the amount used is too small, it tends to take a long time to produce the urethane bond-containing compound, and if it is too large, the liquid haze of the obtained urethane bond-containing compound tends to be high.

[0046] The present invention uses the above-mentioned hydroxyl group-containing compound (A), isocyanate group-containing compound (B), and bismuth-based compound (α), and produces a urethane bond-containing compound by reacting the hydroxyl group-containing compound (A) with the isocyanate group-containing compound (B) in the presence of the bismuth-based compound (α). The greatest feature of the present invention is that the water content in the reaction system during the urethane reaction is kept at 700 ppm or less.

[0047] The water content in the reaction system hydrolyzes the bismuth compound (α), producing bismuth hydroxide and deactivating the catalytic function. Therefore, in the present invention, the water content in the reaction system is set to 700 ppm or less, which prevents the deactivation of the catalytic function of the bismuth compound (α), prevents the progress of the urethane reaction from being hindered, and makes it possible to obtain the desired urethane bond-containing compound that is transparent, not cloudy, and has excellent reactivity.

[0048] As mentioned above, it is important that the amount of water in the reaction system be 700 ppm or less, preferably 600 ppm or less, and particularly preferably 500 ppm or less. If the amount of water is too high, the catalytic function is deactivated, reducing reactivity, and it takes time to produce a urethane bond-containing compound. The lower limit of the amount of water is better, but it is difficult to achieve zero, and it is usually 100 ppm.

[0049] The amount of water in the reaction system can be measured by the Karl Fischer method.

[0050] The amount of water in the reaction system can be adjusted, for example, by controlling the production process or by adjusting the amount of feed, but the major factor that determines the amount of water is the amount of water derived from the raw materials. Therefore, it is preferable to adjust the amount of water in the hydroxyl group-containing compound (A).

[0051] Therefore, the water content of the hydroxyl group-containing compound (A) is preferably 1000 ppm or less, more preferably 900 ppm or less, and particularly preferably 800 ppm or less. If the water content is too high, the reactivity decreases due to the deactivation of the catalytic function as described above, and it tends to take a long time to produce the urethane bond-containing compound.

[0052] The isocyanate group-containing compound (B) reacts with moisture, resulting in poor storage stability, and therefore contains no or almost no moisture to begin with.

[0053] In the method for producing the urethane bond-containing compound of the present invention, the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B) are charged into a reactor either together or separately and reacted.

[0054] In the reaction between the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B), the hydroxyl group of the hydroxyl group-containing compound (A) and the isocyanate group of the isocyanate group-containing compound (B) are subjected to an addition reaction, for example, at a temperature of 40 to 100°C, preferably 60 to 90°C.

[0055] In addition, in the reaction, organic solvents that do not have a functional group that reacts with an isocyanate group, such as esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene, can be used. Here too, it is preferable to use an organic solvent with a low water content, and it is preferable to select the organic solvent taking into consideration the water content in the reaction system.

[0056] In the reaction between the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B), it is preferable to terminate the reaction when the content of residual isocyanate groups in the reaction system reaches about 0.5% by weight or less, thereby obtaining a urethane bond-containing compound.

[0057] Thus, the production method of the present invention makes it possible to obtain a urethane bond-containing compound that is excellent in reactivity, productivity, and environmental hygiene, without using an organotin compound.

[0058] In the present invention, the urethane bond-containing compound is, for example, (1) A polyol (a2) may be used as the hydroxyl group-containing compound (A) and a polyvalent isocyanate (b1) may be used as the isocyanate group-containing compound (B), and the polyol (a2) and the polyvalent isocyanate (b1) may be reacted to form a polyurethane resin. (2) A hydroxyl group-containing (meth)acrylate (a1) may be used as the hydroxyl group-containing compound (A) and a polyvalent isocyanate (b1) may be used as the isocyanate group-containing compound (B), and the hydroxyl group-containing (meth)acrylate (a1) and the polyvalent isocyanate (b1) may be reacted to form a urethane (meth)acrylate compound (UA1). (3) A hydroxyl group-containing (meth)acrylate (a1) and a polyol (a2) can be used as the hydroxyl group-containing compound (A), and a polyvalent isocyanate (b1) can be used as the isocyanate group-containing compound (B), and a urethane (meth)acrylate compound (UA2) can be prepared by reacting the polyol (a2), the polyvalent isocyanate (b1), and the hydroxyl group-containing (meth)acrylate (a1).

[0059] Among the above, the urethane (meth)acrylate-based compound (UA1) and the urethane (meth)acrylate-based compound (UA2) are preferred because they are also useful as raw materials for active energy ray-curable resin compositions (hereinafter, the urethane (meth)acrylate-based compounds (UA1) and (UA2) may be collectively abbreviated as the urethane (meth)acrylate-based compound (UA)).

[0060] Specifically, the urethane (meth)acrylate compound (UA1) is reacted by adjusting the functional group molar ratio between the hydroxyl groups of the hydroxyl group-containing (meth)acrylate (a1) and the isocyanate groups of the polyvalent isocyanate (b1). Regarding the reaction molar ratio of the hydroxyl group-containing (meth)acrylate (a1) and the polyvalent isocyanate (b1), for example, when the hydroxyl group-containing (meth)acrylate (a1) has one hydroxyl group and the polyvalent isocyanate (b1) has two isocyanate groups, the hydroxyl group-containing (meth)acrylate (a1):polyvalent isocyanate (b1) ratio is about 2:1, and when the polyvalent isocyanate (b1) has three isocyanate groups, the hydroxyl group-containing (meth)acrylate (a1):polyvalent isocyanate (b1) ratio is about 3:1.

[0061] In the addition reaction of the hydroxyl group-containing (meth)acrylate (a1) and the polyisocyanate (b1), the reaction can be terminated when the residual isocyanate group content in the reaction system reaches 0.5% by weight or less, thereby obtaining a urethane (meth)acrylate compound (UA1).

[0062] In the production of the urethane (meth)acrylate compound (UA1), as described above, it is important to adjust the amount of water in the reaction system to 700 ppm or less, preferably 600 ppm or less, and more preferably 500 ppm or less, and it is particularly important to adjust the amount of water in the hydroxyl group-containing (meth)acrylate (a1).

[0063] Furthermore, from the viewpoint of handleability, the weight-average molecular weight of the urethane (meth)acrylate compound (UA1) used in the present invention is preferably 500 to 50000, more preferably 1000 to 30000. If the weight-average molecular weight is too small or too large, the viscosity becomes high and handling tends to be difficult.

[0064] The weight-average molecular weight mentioned above is the weight-average molecular weight converted into the molecular weight of standard polystyrene. The sample was analyzed using a high-performance liquid chromatograph (manufactured by Japan Waters, "Waters 2695 (main body)" and "Waters 2414 (detector)") with a Shodex GPC KF-806L column (exclusion limit molecular weight: 2 × 10 7 Separation range: 100 to 2 × 10 7 The measurement is performed using three columns in series (theoretical plate number: 10,000 columns / column, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm).

[0065] Furthermore, the viscosity of the urethane (meth)acrylate compound (UA1) at 60°C is preferably 500 to 150,000 mPa·s, particularly preferably 500 to 120,000 mPa·s, and even more preferably 1,000 to 100,000 mPa·s. If the viscosity is outside the above range, the coatability tends to decrease. The viscosity was measured using an E-type viscometer.

[0066] On the other hand, the urethane (meth)acrylate compound (UA2) may be prepared by charging the hydroxyl group-containing (meth)acrylate (a1), the polyol compound (a2), and the polyisocyanate (b1) into a reactor all at once or separately and reacting them. However, from the viewpoints of reaction stability, reduction of by-products, etc., it is preferable to react the polyol (a2) with the polyisocyanate (b1) in advance to obtain a reaction product, and then react the hydroxyl group-containing (meth)acrylate (a1).

[0067] In the reaction between the polyol (a2) and the polyisocyanate (b1), for example, the molar ratio of the isocyanate groups in the polyisocyanate (b1) to the hydroxyl groups in the polyol (a2) is usually set to about 2n:(2n-2) (n is an integer of 2 or more), thereby obtaining a reaction product (a urethane compound containing a terminal isocyanate group) in which the isocyanate groups remain, which then enables an addition reaction with the hydroxyl group-containing (meth)acrylate (a1).

[0068] In the addition reaction of the reaction product obtained by previously reacting the polyol (a2) with the polyisocyanate (b1), with the hydroxyl group-containing (meth)acrylate (a1), the molar ratio of reaction product to hydroxyl group-containing (meth)acrylate (a1) is, for example, about 1:2 when the reaction product has two isocyanate groups and the hydroxyl group-containing (meth)acrylate (a1) has one hydroxyl group; and the molar ratio of reaction product to hydroxyl group-containing (meth)acrylate (a1) is about 1:3 when the reaction product has three isocyanate groups and the hydroxyl group-containing (meth)acrylate (a1) has one hydroxyl group.

[0069] In the addition reaction of the above reaction product with the hydroxyl group-containing (meth)acrylate (a1), the reaction is terminated when the content of residual isocyanate groups in the reaction system reaches 0.1% by weight or less, thereby obtaining a urethane (meth)acrylate compound (UA2).

[0070] In the production of the urethane (meth)acrylate compound (UA2), as described above, it is important to adjust the water content in the reaction system to 700 ppm or less, preferably 600 ppm or less, and more preferably 5000 ppm or less, and it is particularly important to adjust the water content as the total amount of the water content in the hydroxyl group-containing (meth)acrylate (a1) and the water content in the polyol (a2).

[0071] Furthermore, from the viewpoint of handleability, the weight-average molecular weight of the urethane (meth)acrylate compound (UA2) used in the present invention is preferably 500 to 50000, more preferably 1000 to 30000. If the weight-average molecular weight is too small or too large, the viscosity becomes high and handling tends to be difficult. The weight average molecular weight is measured in the same manner as above.

[0072] Furthermore, the viscosity of the urethane (meth)acrylate compound (UA2) at 60°C is preferably 500 to 150,000 mPa·s, particularly preferably 500 to 120,000 mPa·s, and even more preferably 1,000 to 100,000 mPa·s. If the viscosity is outside the above range, the coatability tends to decrease. The viscosity is measured using an E-type viscometer, as described above.

[0073] Thus, the production method of the present invention can produce a urethane bond-containing compound, and among them, the urethane (meth)acrylate compound (UA) is useful as a raw material for an active energy ray-curable resin composition. The active energy ray-curable resin composition will be described below.

[0074] The urethane (meth)acrylate compound (UA) may be used in combination with an ethylenically unsaturated monomer, preferably a (meth)acrylate, if necessary. The (meth)acrylate used in combination may be a monofunctional (meth)acrylate, a bifunctional (meth)acrylate, or a trifunctional or higher functional (meth)acrylate.

[0075] Examples of such monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-stearyl (meth)acrylate, phenoxyethyl (meth)acrylate, glycerin mono(meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, benzyl (meth)acrylate, phenol ethylene oxide modified (n=2) (meth)acrylate, nonylphenol propylene oxide modified (n=2. 5) (Meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate, furfuryl (meth)acrylate, carbitol (meth)acrylate, benzyl (meth)acrylate, butoxyethyl (meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and the like.

[0076] Furthermore, Michael adducts of (meth)acrylic acid [e.g., acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, etc.], 2-(meth)acryloyloxyalkyl dicarboxylic acid monoesters, preferably 2-(meth)acryloyloxyethyl dicarboxylic acid monoesters [e.g., 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid monoester, etc.] are also useful.

[0077] Examples of bifunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and ethylene oxide-modified bisphenol A. Examples of suitable esters include bisphenol A di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid diglycidyl ester di(meth)acrylate, and hydroxypivalic acid-modified neopentyl glycol di(meth)acrylate.

[0078] Examples of trifunctional or higher (meth)acrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, and glycerin polyglycidyl ether poly(meth)acrylate. Examples of ethylenically unsaturated monomers other than (meth)acrylates include styrene, vinyltoluene, chlorostyrene, α-methylstyrene, acrylonitrile, vinyl acetate, and N-vinylpyrrolidone.

[0079] The amount of the ethylenically unsaturated monomer is not particularly limited, but is preferably 0 to 200 parts by weight, more preferably 5 to 120 parts by weight, and even more preferably 10 to 65 parts by weight, per 100 parts by weight of the urethane (meth)acrylate compound (UA). If the amount exceeds 200 parts by weight, adhesion to the substrate tends to decrease in coating agent applications.

[0080] The active energy ray-curable resin composition containing the urethane (meth)acrylate compound (UA) is cured by irradiation with active energy rays. Examples of the active energy rays that can be used include light rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and gamma rays, as well as electron beams, proton beams, and neutron beams. However, curing by ultraviolet irradiation is advantageous in terms of curing speed, ease of obtaining irradiation equipment, cost, and the like. For UV curing, high-pressure mercury lamps, metal halide lamps, xenon lamps, chemical lamps, LEDs, etc. that emit light in the 150 to 450 nm wavelength range are used, with an output of 100 to 3000 mJ / cm. 2 It is enough to irradiate it to some extent.

[0081] For curing by ultraviolet irradiation, it is preferable to use a photopolymerization initiator, and the photopolymerization initiator is not particularly limited as long as it generates radicals by the action of light. Specifically, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylenephenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl diphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, camphorquinone, dibenzosuberone, 2-ethylanthraquinone, 4',4"-diethylisophthalophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, α-acyloxime ester, acylphosphazene Examples of suitable oxime esters include sphingoside, methylphenyl glyoxylate, benzil, 9,10-phenanthrenequinone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-[4(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime).Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl) ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one are preferably used. These photopolymerization initiators (C) may be used alone or in combination of two or more.

[0082] The amount of such photopolymerization initiator to be added is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the urethane (meth)acrylate compound (UA) (if an ethylenically unsaturated monomer is further contained, the total amount of the urethane (meth)acrylate compound (UA) and the ethylenically unsaturated monomer). If the amount is too small, the curing speed of the ultraviolet curing tends to become extremely slow, and if the amount is too large, the curability is not improved and it is useless.

[0083] Furthermore, as an auxiliary agent for the photopolymerization initiator, for example, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler's ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, (n-butoxy)ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, etc. can also be used in combination.

[0084] The active energy ray-curable resin composition may also contain additives such as antioxidants, flame retardants, antistatic agents, fillers, leveling agents, stabilizers, reinforcing agents, matting agents, and abrasives. Other diluents may also be added, and examples of such diluents include ethyl acetate, butyl acetate, toluene, xylene, methanol, ethanol, butanol, acetone, methyl isobutyl ketone, methyl ethyl ketone, cellosolves, and diacetone alcohol.

[0085] Thus, in the present invention, when a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B) are reacted in the presence of a bismuth compound (α) to produce a urethane bond-containing compound, the water content in the reaction system is kept at 700 ppm or less, making it possible to produce a urethane bond-containing compound that is excellent in reactivity, productivity, and environmental hygiene, even without using an organotin compound. Furthermore, the resulting urethane bond-containing compound, particularly the urethane (meth)acrylate compound (UA), can be used to obtain an active energy ray-curable resin composition, which is useful for a variety of applications, such as paints, coatings, adhesives, pressure-sensitive adhesives, adhesives, and inks, and is particularly useful as an adhesive, pressure-sensitive adhesive, or coating agent for high-precision parts in the electrical and electronic fields. [Example]

[0086] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" and "%" are by weight.

[0087] [Polyol-free urethane acrylate] Example 1 A four-neck flask equipped with a thermometer, a reflux condenser, and a stirrer and a temperature-controllable jacket was placed in the flask. 291.1 g of hexamethylene diisocyanate trimer (isocyanate group content: 21.3%, manufactured by Tosoh Corporation, "Coronate HX"), 708.9 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate with a water content of 500 ppm (hydroxyl value: 120 mg KOH / g), and 0.8 g of 2,6-di-t-butyl-4-methylphenol were placed in the flask. A bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid mixed reaction catalyst (manufactured by OMG Brochers GmbH, "Borchi"). 0.02 g of Kat24 was added, and the temperature was gradually raised to 70°C while stirring. The internal temperature was maintained at 70°C to allow the reaction to proceed. It was confirmed that the concentration of free isocyanate groups was 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C: 17,000 mPa·s, weight average molecular weight: 7,200, resin content: 100%).

[0088] Example 2 A four-neck flask equipped with a thermometer, a reflux condenser, and a stirrer and a temperature-controllable jacket was placed in the flask. 66.2 g of isophorone diisocyanate (isocyanate group content: 37.8%), 933.8 g of a mixture of dipentaerythritol penta(meth)acrylate and dipentaerythritol hexaacrylate (hydroxyl value: 48 mg KOH / g) with a water content of 400 ppm, and 0.06 g of 2,6-di-t-butyl-4-methylphenol were placed in the flask. A bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid mixed reaction catalyst (manufactured by OMG Brochers GmbH, "Borchi" ) was added to the flask. 0.08 g of Kat24 was added, and the temperature was gradually raised to 70°C while stirring. The internal temperature was maintained at 70°C to allow the reaction to proceed. It was confirmed that the concentration of free isocyanate groups was 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C: 1700 mPa·s, weight average molecular weight: 1800, resin content: 100%).

[0089] Example 3 A four-neck flask equipped with a thermometer, a reflux condenser, and a stirrer and a temperature-controllable jacket was placed in the flask. 603.5 g of hexamethylene diisocyanate trimer (isocyanate group content: 21.3%, manufactured by Tosoh Corporation, "Coronate HX"), 396.5 g of 2-hydroxypropyl acrylate (hydroxyl value: 431 mg KOH / g) with a water content of 1000 ppm, 0.05 g of 2,6-di-t-butyl-4-methylphenol, and 0.4 g of 4-methoxyphenol were placed in the flask. A mixed reaction catalyst of bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid (manufactured by OMG Brochers GmbH, "Borchi" was added to the flask. 0.1 g of Kat24 was added, and the temperature was gradually raised to 70°C while stirring. The internal temperature was maintained at 70°C to allow the reaction to proceed. It was confirmed that the concentration of free isocyanate groups was 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C: 13,000 mPa·s, weight average molecular weight: 2,400, resin content: 100%).

[0090] (Comparative Example 1) In Example 1, a similar reaction was carried out using a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g) with a water content of 1100 ppm. The free isocyanate group concentration was confirmed to be 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C 13000 mPa s, weight-average molecular weight 2300, resin content 100%).

[0091] (Comparative Example 2) A similar reaction was carried out using a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g) with a water content of 1050 ppm in Example 1. Bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid (Borchi Kat24, manufactured by OMG Brochers GmbH) were added as needed to confirm that the free isocyanate group concentration was 0.1% or less, yielding a urethane acrylate (viscosity at 60°C: 13,000 mPa s, weight-average molecular weight: 2,300, resin content: 100%).

[0092] (Comparative Example 3) A similar reaction was carried out using a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g) with a water content of 1900 ppm in Example 1. Bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid (Borchi Kat24, manufactured by OMG Brochers GmbH) were added as needed to confirm that the free isocyanate group concentration was 0.1% or less, yielding a urethane acrylate (viscosity at 60°C: 13,000 mPa s, weight-average molecular weight: 2,300, resin content: 100%).

[0093] Comparative Example 4 A similar reaction was carried out using hydroxypropyl acrylate (hydroxyl value: 431 mgKOH / g) with a water content of 2000 ppm in Example 3. Bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid mixed reaction catalyst ("Borchi Kat24" manufactured by OMG Brochers GmbH) was added as needed, and the free isocyanate group concentration was confirmed to be 0.1% or less, yielding a urethane acrylate (viscosity at 60°C: 13000 mPa s, weight-average molecular weight: 2400, resin content: 100%).

[0094] (Comparative Example 5) A similar reaction was carried out as in Example 1, except that a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g) with a water content of 1100 ppm and 0.02 g of dibutyltin laurate was used as the reaction catalyst. It was confirmed that the concentration of free isocyanate groups was 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C 13000 mPa s, weight-average molecular weight 2300, resin content 100%).

[0095] (Comparative Example 6) A similar reaction was carried out in Example 1, except that the reaction catalyst was changed to 0.02 g of dibutyltin laurate. The free isocyanate group concentration was confirmed to be 0.1% or less, and a urethane acrylate was obtained (viscosity at 60°C: 13,000 mPa s, weight-average molecular weight: 2,300, resin content: 100%).

[0096] The reactivity and transparency of the production methods of the above Examples and Comparative Examples were evaluated as follows.

[0097] <Reactivity> The time until a urethane acrylate was obtained (until the concentration of free isocyanate groups reached 0.1% or less) by the production methods of the above Examples and Comparative Examples was measured as the reaction time, and the reactivity was evaluated according to the following criteria. (Evaluation criteria) 〇...10 hours or less ×...Over 10 hours

[0098] <Transparency> The urethane acrylates obtained in the above Examples and Comparative Examples were mixed with ethyl acetate as a diluent at a weight ratio of urethane acrylate / ethyl acetate = 80 / 20 to obtain active energy ray-curable resin compositions. The liquid haze of the obtained active energy ray-curable resin composition was measured with a haze meter, and the transparency was evaluated according to the following criteria. (Evaluation criteria) ○ 1.0 or less ×...1.0 or more

[0099] The results of the above examples and comparative examples are shown in Table 1.

[0100] [Table 1]

[0101] From the above results, it can be seen that in the examples where the amount of water in the reaction system was low and below the specified amount, the reactivity was excellent even when a bismuth-based compound was used as a catalyst, and furthermore, the obtained urethane acrylate had excellent transparency. In contrast, in Comparative Examples 1 to 4, where the water content in the reaction system was high, it took a long time to obtain the urethane acrylate. Furthermore, in Comparative Examples 3 and 4, although the amount of catalyst was increased to enhance the reactivity, little improvement in reactivity was observed, and the obtained urethane acrylate had poor transparency. Furthermore, in Comparative Examples 5 and 6, in which dibutyltin laurate was used as the catalyst, there was a problem with environmental hygiene, and the object of the present invention was not satisfied.

[0102] [Polyol-containing urethane acrylate] Example 4 A four-neck flask equipped with a thermometer, a reflux condenser, and a stirrer was fitted with a temperature-controllable jacket. 133.02 g of isophorone diisocyanate (isocyanate group content: 37.8%), 821.45 g of OD-X-2330 (number average molecular weight: 3,300, hydroxyl value: 56 mg KOH / g) as a polyol with a water content of 370 ppm, and 0.8 g of 2,6-di-t-butyl-4-methylphenol were charged into the four-neck flask, and 0.015 g of a mixed reaction catalyst of bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid (manufactured by OMG Brochers GmbH, "Borchi Kat24") was added. The mixture was gradually heated to 70°C with stirring, and the internal temperature was maintained at 70°C to allow the reaction to proceed. Next, 45.53 g of 2-hydroxyethyl acrylate (HEA) was added to this system and allowed to react. The reaction was terminated when the free isocyanate group concentration reached 0.1% or less, yielding a urethane acrylate (viscosity at 60°C: 72,000 mPa·s, weight-average molecular weight: 6,000, resin content: 100%).

[0104] (Comparative Example 8) A four-neck flask equipped with a thermometer, a reflux condenser, and a stirrer was fitted with a temperature-controllable jacket, and the four-neck flask was charged with 133.02 g of isophorone diisocyanate (isocyanate group content: 37.8%), 821.45 g of OD-X-2330 (number average molecular weight 3,300, hydroxyl value 56 mgKOH / g) as a polyol with a water content of 900 ppm, and 0.8 g of 2,6-di-t-butyl-4-methylphenol. 0.07 g of a mixed reaction catalyst of bismuth tris(2-ethylhexanoate) and 2-ethylhexanoic acid (manufactured by OMG Brochers GmbH, "Borchi Kat24") was added, and the temperature was gradually raised to 70°C with stirring, and the internal temperature was maintained at 70°C to allow the reaction to proceed. Next, 45.53 g of 2-hydroxyethyl acrylate (HEA) was added to this system and allowed to react. The reaction was terminated when the free isocyanate group concentration reached 0.1% or less, yielding urethane acrylate (viscosity at 60°C: 70,000 mPa·s, weight-average molecular weight: 7,000, resin content: 100%).

[0105] The reactivity and transparency of the production methods of the above Examples and Comparative Examples were evaluated as follows.

[0106] <Reactivity> The time until a urethane acrylate was obtained (until the concentration of free isocyanate groups reached 0.1% or less) by the production methods of the above Examples and Comparative Examples was measured as the reaction time, and the reactivity was evaluated according to the following criteria. (Evaluation criteria) 〇...20 hours or less ×...Over 20 hours

[0107] <Transparency> The urethane acrylates obtained in the above Examples and Comparative Examples were mixed with ethyl acetate as a diluent at a weight ratio of urethane acrylate / ethyl acetate = 80 / 20 to obtain active energy ray-curable resin compositions. The liquid haze of the obtained active energy ray-curable resin composition was measured with a haze meter, and the transparency was evaluated according to the following criteria. (Evaluation criteria) ○ 1.0 or less ×...1.0 or more

[0108] The results of the above examples and comparative examples are shown in Table 2.

[0109] [Table 2]

[0110] From the above results, it can be seen that in the examples where the amount of water in the reaction system was low and below the specified amount, the reactivity was excellent even when a bismuth-based compound was used as a catalyst, and furthermore, the obtained urethane acrylate had excellent transparency. In contrast, in the case of Comparative Example 8, in which the water content in the reaction system was high, it took a long time to obtain the urethane acrylate. Furthermore, although the amount of catalyst was increased to increase the reactivity, little improvement in reactivity was observed, and the obtained urethane acrylate had poor transparency. 。 [Industrial Applicability]

[0111] According to the production method of the present invention, a urethane reaction can be carried out with excellent reactivity, productivity, and environmental hygiene without using an organotin compound, and a urethane bond-containing compound can be obtained. Among the urethane bond-containing compounds, for example, a urethane (meth)acrylate-based compound is useful as a raw material for an active energy ray-curable resin composition, and can be used for various applications such as a coating agent, an adhesive, and a pressure-sensitive adhesive.

Claims

1. A method for producing a urethane bond-containing compound, comprising reacting a hydroxyl group-containing (meth)acrylate (a1) which is a hydroxyl group-containing compound (A) with a polyvalent isocyanate (b1) which is an isocyanate group-containing compound (B) in the presence of a bismuth compound (α) to produce a polyol-free urethane (meth)acrylate compound (UA1) which is a urethane bond-containing compound and does not contain in its molecular structure a structure derived from a compound having two or more hydroxyl groups other than the hydroxyl group-containing (meth)acrylate (a1), wherein the water content in the reaction system is 350 ppm or more and 700 ppm or less.

2. 2. The method for producing a urethane bond-containing compound according to claim 1, wherein the water content of the hydroxyl group-containing compound (A) is 1000 ppm or less.

3. 3. The method for producing a urethane bond-containing compound according to claim 1, wherein the bismuth compound (α) is an organic bismuth compound.

4. The method for producing a urethane bond-containing compound according to any one of claims 1 to 3, characterized in that the amount of the bismuth compound (α) used is 0.001 to 0.02% by weight based on the total amount of the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B).

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