One-component moisture-curing urethane resin composition and coating material using the same

Abstract

To provide a one-pack moisture-curable urethane resin composition that excels in storage stability and curability as one liquid, and has sufficiently high weather resistance and impact resistance after curing, and also to provide a coating material using the same.SOLUTION: Disclosed is a one-pack moisture-curable urethane resin composition comprising a urethane prepolymer and oxazolidine, wherein the urethane prepolymer is synthesized from a polyisocyanate and a polyol comprising a polycarbonate polyol (PC) and an acrylic polyol (AC) having a hydroxyl value of 60 to 150 mgKOH / g and a glass transition temperature Tg of more than 60°C and 140°C or less. Also disclosed is a coating material comprising the one-pack moisture-curable urethane resin composition and an aromatic solvent and / or an ether-based solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a one-component moisture-curable urethane resin composition and a coating material using the same. More specifically, the present invention relates to a one-component moisture-curable urethane resin composition having excellent weather resistance and a coating material using the same. [Background technology]

[0002] One-component moisture-curing urethane resins are used in adhesives, paints, coating materials, sealants, etc. because of their adhesion to substrates, ease of adjusting physical properties, ease of handling, etc. Here, a high level of weather resistance is required for urethane resins, particularly in paints and coating materials that are exposed directly to sunlight. On the other hand, paints and coating materials also require durability against external forces, such as impact resistance.

[0003] Patent Document 1 proposes a one-component moisture-curing urethane resin with excellent weather resistance that contains a resin made of an acrylic polyol and a hydroxyl-containing oxazolidine, and a urethane prepolymer. This is a resin made of an acrylic polyol, a polyisocyanate, and a hydroxyl-containing oxazolidine, and is expected to exhibit a certain degree of weather resistance. However, when used in paints, coating materials, etc., the resins used therein are required to have an even higher level of weather resistance, and urethane resins made of this composition do not have sufficient weather resistance.

[0004] On the other hand, as a highly weather-resistant coating composition, a urethane resin composed of polycarbonate polyol, acrylic polyol, and polyisocyanate is widely known as a two-component curing type (Patent Document 2, etc.).

[0005] However, it is difficult to achieve both weather resistance and impact resistance with these compositions, and they do not suggest a one-component moisture-curable urethane resin composition. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-20425 [Patent Document 2] Patent No. 7051971 [Patent Document 3] Patent Publication No. 2021-98774 [Patent Document 4] Patent Publication No. 2021-98775 [Patent Document 5] Japanese Patent Publication No. 2020-94085 [Patent Document 6] Japanese Patent Application Laid-Open No. 2016-113551 [Patent Document 7] JP 2016-785 A [Patent Document 8] Japanese Patent Application Laid-Open No. 2013-116993 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a one-component moisture-curable urethane resin composition that has excellent storage stability and curability as a one-component, and that has high weather resistance and impact resistance, particularly excellent weather resistance, after curing, and a paint using the same. [Means for solving the problem]

[0008] The object of the present invention is to provide a urethane prepolymer and an oxazolidine compound In the moisture-curable resin composition comprising the above, the urethane prepolymer is polycarbonate polyol (PC) and A polyol consisting of an acrylic polyol (AC) having a hydroxyl value of 60 to 150 mgKOH / g and a glass transition temperature Tg of more than 60°C and not more than 140°C, and a polyisocyanate. and is synthesized from It is a urethane prepolymer having an isocyanate group at the end, and the total of PC and AC in the polyol is 80 mass% or more. This is achieved by a one-component moisture-curable urethane resin composition, and a coating material containing this one-component moisture-curable urethane resin composition and an aromatic solvent and / or an ether solvent. [Effects of the Invention]

[0009] The urethane resin composition of the present invention has excellent storage stability as a one-component, and because it is moisture-curable, it cures with atmospheric moisture to form a cured product. Furthermore, the cured product of this one-component moisture-curable urethane resin composition has excellent effects such as high weather resistance and impact resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] The urethane prepolymer used is a urethane prepolymer having an isocyanate group at the end, synthesized from a polyol and a polyisocyanate, in which the polyol is made of a polycarbonate polyol (PC) and an acrylic polyol (AC).

[0011] Examples of polycarbonate polyols include those obtained by reacting at least one aliphatic polyhydric alcohol, such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, or cyclohexanedimethylol, with a dialkylene carbonate or dialkyl carbonate, such as diethylene carbonate, dimethyl carbonate, or diethyl carbonate, in which the alkylene or dialkyl group has 2 to 10 carbon atoms. Such polycarbonate polyols preferably have a number average molecular weight Mn of 500 to 3000, and commercially available products such as ETERNACOLL UH-50, UH-100, UH-200, UH-300, PH-50, PH-100, PH-200, PH-300, UC-100, and UM-90U manufactured by UBE, and Nipporan 981, 980R, 982R, 965, 963, 964, and 968 manufactured by Tosoh can be used as they are.

[0012] Examples of acrylic polyols having a hydroxyl value of 60 to 150 mgKOH / g include homopolymers or copolymers of (meth)acrylic monomers having hydroxyl groups, or copolymers of (meth)acrylic monomers having hydroxyl groups with other monomers having polymerizable unsaturated bonds, each having a predetermined hydroxyl value. The acrylic polyol used in the one-component moisture-curing urethane resin preferably has an average of 2 to 8 hydroxyl groups per molecule.

[0013] Examples of (meth)acrylic monomers having a hydroxyl group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, as well as triol (meth)acrylic acid monoesters such as glycerin (meth)acrylic acid monoester and trimethylolpropane (meth)acrylic acid monoester. These may be used alone or in combination of two or more.

[0014] Other monomers having a polymerizable unsaturated bond can also be used in combination, and examples thereof include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate; (meth)acrylic acid; (meth)acrylic acid IsobornylExamples of suitable acrylic acid include unsaturated carboxylic acids such as maleic acid and itaconic acid, unsaturated amides such as (meth)acrylamide and N-methylol (meth)acrylamide, styrene, vinyl toluene, vinyl acetate, and acrylonitrile. These may be used alone or in combination of two or more. Among these, (meth)acrylic acid esters such as alkyl (meth)acrylate and / or alkoxyalkyl (meth)acrylate are preferably used in terms of weather resistance.

[0015] The polyisocyanate may be an aliphatic, aromatic or alicyclic polyisocyanate. Examples of such isocyanates include MDI (diphenylmethane diisocyanate), hydrogenated MDI, 1,5-naphthalene diisocyanate, tolylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylene diisocyanate (TMXDI), 1,8-diisocyanatomethyloctane, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, and derivatives thereof such as modified products (biuret, allophanate, isocyanurate), and trimethylolpropane adducts, and from the viewpoint of weather resistance, aliphatic polyisocyanates such as isophorone diisocyanate and derivatives thereof are preferred.

[0016] Other polyols can be used to adjust physical properties, provided that the weather resistance of the cured product is not impaired, specifically, in a proportion of less than 20% by weight of the total polyols. Using more than 20% by weight of other polyols is undesirable because it can make it difficult to achieve both weather resistance and impact resistance. Examples of such other polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,2,5-hexanetriol, 1,3-butanediol, 1,4-butanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, pentaerythritol propylene oxide, ethylene oxide, butylene oxide, styrene oxide, tetramethylene glycol, polytetramethylene glycol, and polyoxypropylene polyol, with polytetramethylene glycol being preferred.

[0017] When synthesizing the urethane prepolymer, a hydroxyl-containing oxazolidine can be used in an amount of 0.5 equivalents or less relative to the remaining isocyanate groups. Examples of hydroxyl-containing oxazolidines include 2-isopropyl-3-(2-hydroxyethyl)oxazolidine, 2-(1-methylbutyl)-3-(2-hydroxyethyl)oxazolidine, N-hydroxyethyl-2-phenyloxazolidine, and 2-(p-methoxyphenyl)-3-(2-hydroxyethyl)oxazolidine. From the viewpoints of storage stability, curability, and physical properties after curing, 2-isopropyl-3-(2-hydroxyethyl)oxazolidine is preferred. These hydroxyalkyl oxazolidines are synthesized from the corresponding aldehyde or ketone and a hydroxyalkylamine by known methods.

[0018] The acrylic polyol used has a hydroxyl value of 60 to 150 mgKOH / g and a glass transition temperature (Tg) of 0°C or higher, preferably greater than 60°C and less than 140°C from the viewpoint of weather resistance. Here, "greater than 60°C" does not include 60°C. The hydroxyl value of the acrylic polyol affects the viscosity of the urethane prepolymer, which in turn affects the workability of the coating. If the hydroxyl value is less than 60 mgKOH / g, the strength and weather resistance of the coating tend to decrease. On the other hand, if the hydroxyl value exceeds 150 mgKOH / g, impact resistance tends to decrease. Furthermore, the viscosity of the prepolymer increases, which causes problems in prepolymer production. If the glass transition temperature (Tg) is less than 0°C, impact resistance may be excellent but weather resistance may decrease. As the glass transition temperature (Tg) increases, both weather resistance and impact resistance improve. However, if the glass transition temperature (Tg) exceeds 140°C, weather resistance may be excellent but impact resistance may be significantly reduced.

[0019] The mass ratio PC / AC of the polycarbonate polyol (PC) and acrylic polyol (AC) that constitute the urethane prepolymer is 40 / 60 to 90 / 10, and preferably 50 / 50 to 90 / 10. If this ratio is not satisfied, it may be difficult to achieve both weather resistance and impact resistance.

[0020] Furthermore, when the total amount of PC and AC in the polyol is 80% by mass or more, it is possible to provide a resin that is excellent in weather resistance and impact resistance.

[0021] Patent Documents 3 to 8 disclose the combined use of PC and AC as polyols for synthesizing NCO group-containing prepolymers in moisture-curable urethane materials. However, none of these documents teach or suggest that the use of an acrylic polyol with a hydroxyl value of 60 to 150 mgKOH / g improves weather resistance.

[0022] The urethane prepolymer may also contain an oxazolidine compound in which a hydroxyl group-containing oxazolidine has been reacted in advance with a polyisocyanate, preferably a compound in which a hydroxyl group-containing oxazolidine (OH) has been reacted with an isocyanate group (NCO) at a ratio of NCO / OH = 1 / 0.1 to 1 / 1. Here, the polyisocyanate is preferably an aliphatic polyisocyanate.

[0023] The equivalent ratio of isocyanate groups (NCO) to oxazolidine groups (OX) in the urethane resin composition is preferably NCO / OX = 1.0 to 3.0. If the NCO / OX equivalent ratio is less than 1.0, the amount of oxazolidine will be in excess relative to the isocyanate groups, resulting in unreacted amino groups remaining during curing, which can deteriorate weather resistance. On the other hand, if the NCO / OX equivalent ratio exceeds 3.0, the amount of oxazolidine groups (curing agent) will be significantly less than the amount of isocyanate groups, resulting in poor curability.

[0024] The moisture-curable urethane resin composition comprising the above components is dissolved in an aromatic solvent and / or an ether solvent to form a coating material having a solids concentration of 40 to 80 mass % in order to ensure coating thickness and ease of use.

[0025] Examples of the solvent include aromatic hydrocarbons such as toluene, xylene, Solvent Naphtha 100, and Solvent Naphtha 150, and ethers such as diethyl ether, dimethyl ether, ethylene glycol mono-n-butyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monobutyl ether acetate, and propylene glycol monomethyl ether acetate. These may be used alone or in combination of two or more.

[0026] Other additives that may be used as appropriate include antioxidants, ultraviolet absorbers, pigments, thixotropic agents, anti-sagging agents, matting agents, fillers, etc. Preferred thixotropic agents include finely divided silica and amide-based thixotropic agents. [Example]

[0027] Next, the present invention will be described with reference to examples.

[0028] Reference example 1 (1) 66.7 g of propylene glycol monobutyl ether acetate was charged into a four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, and the mixture was heated to 92°C while purging with nitrogen. Next, a mixture of 59.0 g of cyclohexyl methacrylate, 14.5 g of n-butyl acrylate, 14.0 g of 2-hydroxyethyl methacrylate, 12.5 g of 2-hydroxyethyl acrylate, and 2.9 g of tert-butylperoxy-2-ethylhexanoate was added over 4 hours. One hour and two hours after the end of the feed, 0.2 g each of tert-butylperoxy-2-ethylhexanoate was added, and the mixture was allowed to react for another 2 hours to obtain acrylic polyol A. (2) In a 500 ml separable flask equipped with a stirring blade, 35.0 g of dried polycarbonate diol (ETERNACOLL PH-200, hydroxyl value 56 mg KOH / g), 35.0 g of polycarbonate diol (Nippolan PC-982R, hydroxyl value 56 mg KOH / g), and 50.0 g (equivalent to 30.0 g) of acrylic polyol A (number average molecular weight Mn 1830, hydroxyl value 120 mg KOH / g, Tg 28°C, propylene glycol butyl ether acetate 60 mass% solution) were dissolved in 89.0 g of an aromatic solvent (Shin-Nippon Chemical Products R100), and then 36.4 g of isophorone diisocyanate and dibutyl ether acetate were added. tin 0.02 g of dilaurate was added and stirred at room temperature for 1 hour, after which 5.0 g of 2-isopropyl-3-(2-hydroxyethyl)oxazolidine was added and the temperature was gradually raised to 80°C under a nitrogen stream and reacted at 80°C for 2 hours to obtain 250.4 g of urethane prepolymer A.

[0029] (3) Urethane prepolymer A 250.4g Leveling agent (BYK Japan product 0.2g) BYK-UV 3576) UV absorber (Ciba-Geigy UV1164) 5g Light stabilizer (Ciba-Geigy product HALS292) 5g Hardener 13.9g [2-Isopropyl-3-(2-hydroxyethyl) 2 moles of oxazolidine and hexamethylene adduct with 1 mole of diisocyanate; Molecular weight 486.68] Octylic acid 0.03g The mixture was thoroughly stirred to obtain a transparent, one-component, moisture-curable urethane resin composition A (viscosity: 273 mPa·s at 25°C using an E-type viscometer at 100 rpm). The equivalent ratio of isocyanate groups to oxazolidine groups (NCO / OX) was 1.84.

[0030] (4) The obtained one-component moisture-curing urethane resin composition A was mixed with 200.0 g of acrylic polyol (Toa Gosei's Alfon UH2041), 200.0 g of aromatic solvent (Shin-Nippon Chemical's R100), 94.1 g of isophorone diisocyanate, and dibutyl acrylate. tin A urethane primer obtained by reacting 0.3 g of dilaurate with 3.0 g of 3-aminopropyltriethoxysilane was applied to a 0.15 mm thick Nichiha ceramic siding board, and the resulting coating was applied to a thickness of 0.3 mm. The board was then cured and aged for two weeks at 23 (±2) °C and 50 (±10) % RH to obtain a cured coating. Weather resistance and impact resistance tests were then conducted using the resulting cured coating. [Weather resistance test] Testing machine: Iwasaki Electric Co., Ltd. Eye Super UV Tester Test conditions: UV irradiance: 150±8mW / cm 2 Temperature: 63℃ Wavelength: 295~450nm Cycle: 63°C ± 3°C, 50% RH, 4 hours of irradiation ⇒ 4 hours of condensation Test result evaluation: No change after 2000 hours: A+, No change after 1600 hours: A, No change after 1200 hours: B: No change after 800 hours C: Whitening or cracking after 800 hours D: and evaluation [Impact resistance test] Test method: JIS K5600-5-3 (1999) General test method for paints, Part 5: Mechanical properties of coating film, Section 3: Resistance to falling weight, based on DuPont method The paint was applied to a thickness of 0.3 mm on a 2 mm thick acrylic resin cut to 50 mm x 50 mm, and then cured and aged for 2 weeks in an environment of 23 (±2) °C and 50 (±10) % RH. Next, a 6.35 mm radius shot and a stand were attached so that the coated surface was facing up, and a 300 g weight was dropped from a height of 40 cm, 30 cm, or 20 cm, and the appearance of the paint film was observed. Test result evaluation: A: No cracks on the coating at a height of 40cm, B: 30cm, C: 20cm, D: cracks on the coating at a height of 20cm

[0031] Reference example 2 In Reference Example 1, the amounts of the two types of polycarbonate polyols in (2) were each changed to 30 g, the amount of acrylic polyol A to 66.7 g (equivalent to 40 g), the amount of aromatic solvent to 85.3 g, and the amount of isophorone diisocyanate to 38.8 g, and the amount of curing agent in (3) was changed to 16 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.78, viscosity at 25°C at 100 rpm using an E-type viscometer 310 mPa s).

[0032] Reference example 3 In Reference Example 1, the amounts of the two types of polycarbonate polyols in (2) were each changed to 40 g, the amount of acrylic polyol A to 33.3 g (equivalent to 20.0 g), the amount of aromatic solvent to 92.7 g, and the amount of isophorone diisocyanate to 33.9 g, and the amount of curing agent in (3) to 11.6 g, respectively, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.92, viscosity at 25°C at 100 rpm using an E-type viscometer: 248 mPa s).

[0033] Reference example 4 In Reference Example 1, the amounts of the two types of polycarbonate polyols in (2) were each changed to 45 g, the amount of acrylic polyol A to 16.7 g (equivalent to 10.0 g), the amount of aromatic solvent to 87.3 g, the amount of isophorone diisocyanate to 31.5 g, and the amount of curing agent in (3) to 9.5 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 2.01, viscosity at 25°C at 100 rpm using an E-type viscometer 218 mPa s).

[0034] Reference example 5 In Reference Example 1, the amounts of the two types of polycarbonate polyols in (2) were each changed to 25 g, the amount of acrylic polyol A to 83.3 g (equivalent to 50.0 g), the amount of aromatic solvent to 83.3 g, and the amount of isophorone diisocyanate to 41.4 g, and the amount of curing agent in (3) to 18 g were changed, resulting in a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.76, viscosity at 25°C at 100 rpm using an E-type viscometer: 417 mPa s).

[0035] Reference example 6 In Reference Example 1, the amounts of the two types of polycarbonate polyols in (2) were each changed to 47.5 g, the amount of acrylic polyol A to 8.3 g (equivalent to 5.0 g), the amount of aromatic solvent to 98.7 g, and the amount of isophorone diisocyanate to 30.0 g, and the amount of curing agent in (3) to 8.3 g were changed, resulting in a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 2.04, viscosity at 25°C at 100 rpm using an E-type viscometer 203 mPa s).

[0036] Reference example 7 The amount of curing agent in Reference Example 1(3) was changed to 7.0 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 2.71, viscosity 268 mPa·s at 25°C using an E-type viscometer at 100 rpm).

[0037] Reference example 8 A one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.05, viscosity 285 mPa·s at 25°C using an E-type viscometer at 100 rpm) was obtained by changing the amount of curing agent in Reference Example 1(3) to 30.0 g.

[0038] Reference example 9 In Reference Example 1, the amounts of cyclohexyl methacrylate, n-butyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate in (1) were changed to 55.0 g, 12.0 g, 18.0 g, and 15.0 g, respectively, to obtain acrylic polyol B (number average molecular weight Mn 1860, hydroxyl value 150 mgKOH / g, Tg 30°C, 60 wt% solution in propylene glycol butyl ether acetate). In (2), the amount of acrylic polyol A was changed to the same amount of acrylic polyol B, the amount of aromatic solvent was changed to 92.0 g, the amount of isophorone diisocyanate was changed to 39.9 g, and the amount of curing agent in (3) was changed to 16.8 g, respectively, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.78, viscosity at 25°C at 100 rpm using an E-type viscometer of 373 mPa·s).

[0039] Reference example 10 In Reference Example 1, the amounts of cyclohexyl methacrylate, n-butyl acrylate, 20.0 g, 2-hydroxyethyl methacrylate, and 6.6 g, and 6.4 g, respectively, in (1) were changed to 67.0 g, 20.0 g, 20.0 g, 6.6 g, and 6.4 g, respectively, to obtain acrylic polyol C (number average molecular weight Mn 1840, hydroxyl value 60 mgKOH / g, Tg 26°C, 60 wt% solution in propylene glycol butyl ether acetate). In (2), the amount of acrylic polyol A was changed to the same amount of acrylic polyol C, the amount of aromatic solvent was changed to 81.0 g, the amount of isophorone diisocyanate was changed to 29.3 g, and the amount of curing agent in (3) was changed to 10.1 g, respectively, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.79, viscosity at 25°C at 100 rpm using an E-type viscometer of 188 mPa·s).

[0040] Reference example 11 In Reference Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 38.5 g and the amount of n-butyl acrylate to 35 g, respectively, to obtain acrylic polyol D (number average molecular weight Mn 1810, hydroxyl value 120 mgKOH / g, Tg 60°C, 60 wt% solution in propylene glycol butyl ether acetate), and in (2), the acrylic polyol A was changed to the same amount of acrylic polyol D, and the amount of isophorone diisocyanate was changed to 36.3 g, respectively, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.83, viscosity at 25°C at 100 rpm using an E-type viscometer 348 mPa s).

[0041] Reference example 12 In Reference Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 47.5 g and the amount of n-butyl acrylate to 26 g, respectively, to obtain acrylic polyol E (number average molecular weight Mn 1820, hydroxyl value 120 KOHmg / g, Tg 12°C, 60 wt% solution in propylene glycol butyl ether acetate), and in (2), the acrylic polyol A was changed to the same amount of acrylic polyol E, and the amount of isophorone diisocyanate was changed to 36.4 g, respectively, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.84, viscosity at 25°C at 100 rpm using an E-type viscometer 223 mPa s).

[0042] Example 1 In Reference Example 1, the monomers in (1) were changed to 60.0 g of methyl methacrylate, 27.8 g of 2-hydroxyethyl methacrylate, 10.0 g of methyl acrylate, 2.2 g of acrylic acid, and 0.02 g of n-dodecyl mercaptan, to obtain acrylic polyol F (number average molecular weight Mn 1920, hydroxyl value 120 mg KOH / g, Tg 70°C, 60 mass% solution of propylene glycol butyl ether acetate). The acrylic polyol A in (2) was replaced with acrylic polyol F. The amount of the two types of polycarbonate polyols was changed to 25.0 g, the amount of aromatic solvent to 83.3 g, and the amount of isophorone diisocyanate to 41.4 g. Furthermore, the amount of curing agent in (3) was changed to 18.0 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.76, viscosity 421 mPa·S at 25°C using an E-type viscometer at 100 rpm).

[0043] Example 2 In Reference Example 1, the monomer in (1) is Isobornyl The ingredients were changed to 60.0 g of methacrylate, 27.8 g of 2-hydroxyethyl methacrylate, 10.0 g of methyl methacrylate, 2.2 g of methacrylic acid, and 0.02 g of n-dodecyl mercaptan to obtain acrylic polyol G (number average molecular weight Mn 1860, hydroxyl value 120 mg KOH / g, Tg 130 ° C, propylene glycol butyl ether acetate 60 mass % solution), and the acrylic polyol A in (2) was Acrylic polyol G 83.3g (equivalent to 50.0g solids) The amounts of the two types of polycarbonate polyol were changed to 25.0 g each, the amount of aromatic solvent to 83.3 g, and the amount of isophorone diisocyanate to 41.4 g. Furthermore, the amount of curing agent in (3) was changed to 18.0 g, and a one-component moisture-curing urethane resin composition (NCO / OX equivalent ratio 1.76, viscosity 428 mPa·S at 25°C using an E-type viscometer at 100 rpm) was obtained.

[0044] Comparative Example 1 In Reference Example 1, the total amount of polycarbonate polyol in (2) was changed to 70 g of polytetramethylene glycol (Mitsubishi Chemical product PTMG 2000, hydroxyl value 56.0 mg KOH / g), 2-isopropyl-3-(2-hydroxyethyl)oxazolidine was not used, the amount of isophorone diisocyanate was changed to 29.8 g, and the amount of curing agent in (3) was changed to 17.8 g, resulting in a one-component moisture-curing urethane resin composition (viscosity 288 mPa s at 25 ° C., E-type viscometer 100 rpm). The equivalent ratio of isocyanate groups to oxazolidine groups (NCO / OX) was 1.83.

[0045] Comparative Example 2 In Reference Example 1, the two types of polycarbonate diols in (2) were not used, and acrylic polyol A was used. Acrylic Polyol To 100 g of (Alfon UH2041), the amount of aromatic solvent was changed to 38.4 g, the amount of isophorone diisocyanate was changed to 47.0 g, 66.6 g of propylene glycol butyl ether acetate was added, and the amount of curing agent in (3) was changed to 16.0 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.83, viscosity at 25°C at 100 rpm using an E-type viscometer 248 mPa s).

[0046] Comparative Example 3 In Reference Example 1(2), the same amount of acrylic polyol A was used. Acrylic polyol (Toa Gosei products) The amount of Alfon UH2000, hydroxyl value 20 mgKOH / g, Tg -55°C, 50.0 g (equivalent to 30 g) of a 60 wt% propylene glycol butyl ether acetate solution was changed to 50.0 g, and the amount of isophorone diisocyanate was changed to 24.6 g, to obtain a moisture-curable resin composition (NCO / Ox equivalent ratio 1.86, viscosity at 25°C using an E-type viscometer at 100 rpm of 248 mPa·S).

[0047] Comparative Example 4 In Reference Example 1, the same amount of acrylic polyol A in (2) was used. Acrylic polyol (UH2041,A one-component moisture-curing urethane resin composition (NCO / OX equivalent ratio 1.83, viscosity 262 mPa·s at 25°C using an E-type viscometer at 100 rpm) was obtained by changing the amount of isophorone diisocyanate to 36.3 g and the amount of hydroxybenzoate to 120 mgKOH / g (hydroxyl value 120 mgKOH / g, Tg -55°C, 60 wt% solution in propylene glycol butyl ether acetate).

[0048] The results obtained in the above-mentioned Reference Examples, Examples and Comparative Examples are shown in the following table. table example weather resistance Shock resistance Reference Example 1 AA 〃 2 AB 〃 3 AA 〃 4 BA 〃 5 AC 〃 6 BA 〃 7 BA 〃 8 AA 〃 9 AB 〃 10 BA 〃 11 AA 〃 12 BA Example 1 A+B 〃 2 A+ B Comparative example 1 CB 〃 2 BC 〃 3 DA 〃 4 CA

[0049] The one-component moisture-curable urethane resin composition according to the present invention is effectively used as a sealant, adhesive, paint, top coat material, etc., because the cured product obtained by curing the composition with atmospheric moisture has excellent weather resistance and impact resistance, particularly excellent weather resistance.

Claims

1. The moisture-curable resin composition comprises a urethane prepolymer and an oxazolidine compound, wherein the urethane prepolymer is a urethane prepolymer having an isocyanate group at a terminal, synthesized from a polyol composed of a polycarbonate polyol (PC) and an acrylic polyol (AC) having a hydroxyl value of 60 to 150 mgKOH / g and a glass transition temperature Tg of more than 60°C and not more than 140°C, and a polyisocyanate, and the total amount of PC and AC in the polyol is 80 mass% or more.

2. 2. A one-component moisture-curable urethane resin composition according to claim 1, wherein a urethane prepolymer comprising a polycarbonate polyol, an acrylic polyol, and a hydroxyl group-containing oxazolidine is used.

3. 2. The one-component moisture-curable urethane resin composition according to claim 1, wherein the polyisocyanate is an aliphatic polyisocyanate.

4. 4. The one-component moisture-curable urethane resin composition according to claim 1, wherein the urethane prepolymer is blended with an oxazolidine compound obtained by preliminarily reacting a hydroxyl group-containing oxazolidine with a polyisocyanate.

5. 3. The one-component moisture-curable urethane resin composition according to claim 1, wherein the mass ratio of PC / AC is 60 / 40 to 90 / 10.

6. 3. The one-component moisture-curable urethane resin composition according to claim 1, wherein the equivalent ratio of isocyanate groups (NCO) to oxazolidine groups (OX) in the composition is NCO / OX=1.5 to 3.

0.

7. A coating material comprising the one-component moisture-curable urethane resin composition according to claim 1 or 2 and an aromatic solvent and / or an ether solvent.