One-pack moisture-curable urethane resin composition and coating material prepared 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 exhibits sufficiently high weather resistance and impact resistance after curing, and a coating material prepared 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, which comprises a polycarbonate polyol (PC) and an acrylic polyol (AC) with a hydroxyl value of 60-150 mgKOH / g. 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., due to 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 are also required to have durability against external forces, such as impact resistance.

[0003] As a one-component moisture-curing urethane resin with excellent weather resistance, Patent Document 1 proposes one that contains a resin made of acrylic polyol and hydroxyl-containing oxazolidine and a urethane prepolymer. This is a resin made of acrylic polyol, polyisocyanate, and hydroxyl-containing oxazolidine, and it is expected that it will exhibit a certain degree of weather resistance. However, when used in paints, coating materials, etc., the resin used therein is required to have a higher level of weather resistance, and the weather resistance of the urethane resin made of this composition is insufficient.

[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 no one-component moisture-curable urethane resin composition is suggested. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-20425 A [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] JP 2020-94085 A [Patent Document 6] JP 2016-113551 A [Patent Document 7] JP 2016-785 A [Patent Document 8] JP 2013-116993 A 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 which has excellent storage stability and curability as a one-component, and which has high weather resistance and impact resistance after curing, and a coating material using the same. [Means for solving the problem]

[0008] The object of the present invention is achieved by a one-component moisture-curable urethane resin composition comprising a urethane prepolymer and oxazolidine, the urethane prepolymer being synthesized from a polyol comprising a polycarbonate polyol (PC) and an acrylic polyol (AC) having a hydroxyl value of 60 to 150 mgKOH / g, and a polyisocyanate, and by a coating material comprising the one-component moisture-curable urethane resin composition and an aromatic solvent and / or an ether solvent. Effect of the Invention

[0009] The urethane resin composition of the present invention has excellent storage stability as a one-component, and since it is moisture-curable, it has the property of curing with moisture in the air to form a cured product. In addition, 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 PREFERRED EMBODIMENTS

[0010] As the urethane prepolymer, a urethane prepolymer having an isocyanate group at the end, synthesized from a polyol and a polyisocyanate, is used, 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, and cyclohexanedimethylol with a dialkylene carbonate or dialkyl carbonate such as diethylene carbonate, dimethyl carbonate, and diethyl carbonate. Here, the number of carbon atoms of the alkylene group or dialkyl group is 2 to 10. As such polycarbonate polyol, one having a number average molecular weight Mn of 500 to 3000 is preferably used, 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, UM-90U manufactured by UBE, and Nipporan 981, 980R, 982R, 965, 963, 964, 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 of which has 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)acrylic acid esters 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 (meth)acrylic acid monoesters of triols such as (meth)acrylic acid monoesters of trimethylolpropane, etc. Any of these may be used alone, or two or more of them may be used in combination.

[0014] Other monomers having polymerizable unsaturated bonds can also be used in combination, such as 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, and 2-ethylhexyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate; unsaturated carboxylic acids such as (meth)acrylic acid, 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, from the viewpoint of weather resistance, (meth)acrylic acid esters such as alkyl (meth)acrylate and / or alkoxyalkyl (meth)acrylate are preferably used.

[0015] The polyisocyanate may be an aliphatic, aromatic or alicyclic polyisocyanate. Examples of such compounds include diphenylmethane diisocyanate (MDI), 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. From the viewpoint of weather resistance, preferred examples include aliphatic polyisocyanates such as isophorone diisocyanate and derivatives thereof.

[0016] As the polyol, other polyols can be used to adjust the physical properties, as long as the weather resistance of the cured product is not impaired, specifically, at a ratio of less than 20% by mass of the total polyols. Here, if the other polyol is used at a ratio of 20% by mass or more, it may be difficult to achieve both weather resistance and impact resistance, which is not preferable. 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, polyoxypropylene polyol, etc., and preferably polytetramethylene glycol.

[0017] In the synthesis of urethane prepolymer, hydroxyl group-containing oxazolidine can be used in a ratio of 0.5 equivalents or less to the remaining isocyanate group. As the hydroxyl group-containing oxazolidine, hydroxyalkyl oxazolidine such as 2-isopropyl-3-(2-hydroxyethyl)oxazolidine, 2-(1-methylbutyl)-3-(2-hydroxyethyl)oxazolidine, N-hydroxyethyl-2-phenyloxazolidine, 2-(p-methoxyphenyl)-3-(2-hydroxyethyl)oxazolidine, etc. are preferably used, from the viewpoints of storage stability, curing property and physical properties after curing, 2-isopropyl-3-(2-hydroxyethyl)oxazolidine is preferably used. These hydroxyalkyl oxazolidines are synthesized from the corresponding aldehyde or ketone and hydroxyalkylamine by a known method.

[0018] The acrylic polyol used has a hydroxyl value of 60 to 150 mgKOH / g, preferably a glass transition temperature Tg of 0 to 60°C. The hydroxyl value of the acrylic polyol affects the viscosity of the urethane prepolymer, and as a result, also affects the workability of the paint. If the hydroxyl value is less than 60 mgKOH / g, the strength and weather resistance of the coating film tend to decrease. On the other hand, if the hydroxyl value exceeds 150 mgKOH / g, the impact resistance tends to deteriorate. In addition, the viscosity of the prepolymer increases, which is also a problem in prepolymer production. If the glass transition temperature Tg is less than 0°C, the impact resistance is excellent, but the weather resistance may decrease, while if it exceeds 60°C, the weather resistance is excellent, but the impact resistance may decrease.

[0019] The mass ratio of polycarbonate polyol (PC) and acrylic polyol (AC) that make up the urethane prepolymer, PC / AC, is 60 / 40 to 90 / 10, with the amount of PC exceeding the amount of AC. If these ratios are not met, 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 having excellent weather resistance and impact resistance.

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

[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 group (NCO) to oxazolidine group (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 becomes excessive relative to the isocyanate group, so that unreacted amino groups remain during curing, which causes deterioration of weather resistance. On the other hand, if the NCO / OX equivalent ratio exceeds 3.0, the amount of oxazolidine group, which is a curing agent, becomes significantly less than the amount of isocyanate group, which causes deterioration of curing property.

[0024] The moisture-curable urethane resin composition consisting of the above components is dissolved in an aromatic solvent and / or an ether solvent so that the solids concentration is 40 to 80 mass % from the viewpoints of ensuring the coating thickness and workability, to form a coating material.

[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. Here, preferred thixotropic agents include finely powdered silica and amide-based thixotropic agents. EXAMPLES

[0027] The present invention will now be described with reference to examples.

[0028] Example 1 (1) 66.7 g of propylene glycol monobutyl ether acetate was charged into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and the mixture was heated to 92°C while replacing 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 fed 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 aromatic solvent (Shin Nippon Kagaku Products R100), and then 36.4 g of isophorone diisocyanate and 0.02 g of dibutyl dilaurate were added and stirred at room temperature for 1 hour, followed by 2-isopropyl-3-(2-hydroxyethyl)oxazolidine. The mixture was gradually heated to 80° C. in 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 Chemie Japan product 0.2g BYK-UVUV3576) 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] Octyl 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-liquid moisture-curing urethane resin composition A was applied to a thickness of 0.3 mm on a Nichiha ceramic siding board coated with a urethane primer obtained by reacting 3.0 g of 3-aminopropyltriethoxysilane with 200.0 g of acrylic polyol (Toa Gosei product Alfon UH2041), 200.0 g of aromatic solvent (Shin-Nihon Kagaku product R100), 94.1 g of isophorone diisocyanate, and 0.3 g of dibutyl dilaurate to a thickness of 0.15 mm, and cured and aged for 2 weeks under an environment of 23 (± 2) ° C. and 50 (± 10) % RH to obtain a paint cured product on the siding board. Weather resistance test and impact resistance test were performed using the obtained paint cured product. [Weather resistance test] Testing machine: Iwasaki Electric Co., Ltd. Eye Super UV Tester Test conditions: UV illuminance: 150±8mW / cm 2 Temperature: 63℃ Wavelength: 295~450nm Cycle: 63℃±3℃, 50% RH, 4 hours of irradiation ⇒ 4 hours of condensation Test result evaluation: 1600 hours no change A, 1200 hours no change B, 800 hours no change C: Whitening or cracking occurred after 800 hours. D: [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 cured and aged for 2 weeks in an environment of 23 (±2) °C and 50 (±10) % RH. Next, a 6.35 mm radius shot mold and a receiving 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 to observe the appearance of the coating. Test result evaluation: When no cracks occurred on the coating film at a height of 40 cm, it was rated as A, when it was 30 cm, it was rated as B, when it was 20 cm, it was rated as C, when it was 20 cm, it was rated as D.

[0031] Example 2 In 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 further 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] Example 3 In 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, the amount of isophorone diisocyanate to 33.9 g, and the amount of curing agent in (3) to 11.6 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.92, viscosity at 25°C at 100 rpm with an E-type viscometer 248 mPa s).

[0033] Example 4 In 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] Example 5 In 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, the amount of isophorone diisocyanate to 41.4 g, and the amount of curing agent in (3) to 18 g, to obtain 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] Example 6 In Example 1, the amounts of the two types of polycarbonate polyols in (2) were changed to 47.5 g each, the amount of acrylic polyol A to 8.3 g (equivalent to 5.0 g), the amount of aromatic solvent to 98.7 g, the amount of isophorone diisocyanate to 30.0 g, and the amount of curing agent in (3) to 8.3 g, to obtain 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] Example 7 A one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio: 2.71, viscosity at 25° C. at 100 rpm using an E-type viscometer: 268 mPa·s) was obtained by changing the amount of curing agent in Example 1(3) to 7.0 g.

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

[0038] Example 9 In Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 55.0 g, the amount of n-butyl acrylate to 12.0 g, the amount of 2-hydroxyethyl methacrylate to 18.0 g, and the amount of 2-hydroxyethyl acrylate to 15.0 g, respectively, to obtain acrylic polyol B (number average molecular weight Mn 1860, hydroxyl value 150 mgKOH / g, Tg 30°C, propylene glycol butyl ether acetate 60 wt% solution), and the amount of acrylic polyol A in (2) was changed to the same amount of acrylic polyol B, the amount of aromatic solvent to 92.0 g, the amount of isophorone diisocyanate to 39.9 g, and further the amount of curing agent in (3) 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 with an E-type viscometer of 373 mPa·s).

[0039] Example 10 In Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 67.0 g, the amount of n-butyl acrylate to 20.0 g, the amount of 2-hydroxyethyl methacrylate to 6.6 g, and the amount of 2-hydroxyethyl acrylate to 6.4 g, respectively, to obtain acrylic polyol C (number average molecular weight Mn 1840, hydroxyl value 60 mgKOH / g, Tg 26°C, propylene glycol butyl ether acetate 60 wt% solution), and the amount of acrylic polyol A in (2) was changed to the same amount of acrylic polyol C, the amount of aromatic solvent to 81.0 g, the amount of isophorone diisocyanate to 29.3 g, and the amount of curing agent in (3) 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 with an E-type viscometer of 188 mPa·s).

[0040] Example 11 In Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 38.5 g and the amount of n-butyl acrylate was changed 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 of 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 with an E-type viscometer 348 mPa s).

[0041] Example 12 In Example 1, the amount of cyclohexyl methacrylate in (1) was changed to 47.5 g and the amount of n-butyl acrylate was changed 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 with an E-type viscometer 223 mPa s).

[0042] Example 13 In Example 1, the acrylic polyol A in (2) was changed to the same amount of acrylic polyol F (Toa Gosei product Alfon UH2041, hydroxyl value 120 mgKOH / g, Tg -55°C, 60 wt% solution in propylene glycol butyl ether acetate) and the amount of isophorone diisocyanate was changed to 36.3 g, to obtain a one-component moisture-curable urethane resin composition (NCO / OX equivalent ratio 1.83, viscosity at 25°C at 100 rpm with an E-type viscometer 262 mPa s).

[0043] Comparative Example 1 In 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, to obtain a one-liquid moisture-curable urethane resin composition (viscosity at 25°C at 100 rpm using an E-type viscometer: 288 mPa·s). The equivalent ratio of isocyanate group / oxazolidine group (NCO / OX) was 1.83.

[0044] Comparative Example 2 In Example 1, the two types of polycarbonate diols in (2) were not used, and acrylic polyol A was changed to 100 g of acrylic polyol F (Alphon UH2041), the amount of aromatic solvent was changed to 38.4 g, and the amount of isophorone diisocyanate was changed to 47.0 g. In addition, 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 with an E-type viscometer 248 mPa s).

[0045] Comparative Example 3 In Example 1 (2), the acrylic polyol A was changed to the same amount of acrylic polyol G (Toa Gosei Co., Ltd., Alfon UH2000, hydroxyl value 20 mgKOH / g, Tg -55°C, 60 wt% solution in propylene glycol butyl ether acetate) 50.0 g (equivalent to 30 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 at 100 rpm with an E-type viscometer 248 mPa S).

[0046] The results obtained in the above examples and comparative examples are shown in the following table. table example weather resistance Shock-resistance Example 1 AA 〃 2 AB 〃 3AA 〃 4 BA 〃 5 AC 〃 6 BA 〃 7 BA 8 AA 9 AB 〃 10 BA 〃 11 AA 〃 12BA 〃 13 CA Comparative example 1 CB 〃 2BC 〃 3 DA

[0047] The one-component moisture-curable urethane resin composition according to the present invention is effectively used as a sealant, adhesive, paint, topcoat material, etc., since the cured product obtained by curing the composition with moisture in the atmosphere has excellent weather resistance and impact resistance.

Claims

1. The moisture-curable resin composition is a one-component moisture-curable urethane resin composition composed of a urethane prepolymer and an oxazolidine, the urethane prepolymer being 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 polyisocyanate.

2. 2. The moisture-curable urethane resin composition according to claim 1, wherein the glass transition temperature Tg of AC is 0 to 60°C.

3. 2. A one-liquid type moisture-curable urethane resin composition according to claim 1, which uses a urethane prepolymer comprising a polycarbonate polyol, an acrylic polyol and a hydroxyl group-containing oxazolidine.

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

5. 5. The one-liquid type moisture-curable urethane resin composition according to claim 1, further comprising an oxazolidine compound obtained by reacting a hydroxyl group-containing oxazolidine with a polyisocyanate in advance in the urethane prepolymer.

6. 4. 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, and the total amount of PC and AC in the polyol is 80 mass% or more.

7. 4. 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.

8. A coating material comprising the one-component moisture-curable urethane resin composition according to claim 1 or 3 and an aromatic solvent and / or an ether solvent.