Reaction-curable polyurethane resin-forming composition, molded body using said resin-forming composition, and coating agent

Abstract

To provide a molding and a coating agent which have both mechanical characteristics including excellent feeling and breaking strength and moist heat durability, and a reaction curable polyurethane resin formative composition which is environmentally friendly at the time of production of the molding and the coating agent.SOLUTION: A reaction curable polyurethane resin formative composition contains a main agent (A) and a curing agent (B), wherein the main agent (A) contains polyfunctional polyol (a1) and diol (a2), (a1) is obtained from polycarbonate diol and polyester polyol having a functional group number of a hydroxyl group of 3 or more, the curing agent (B) is at least one selected from the group consisting of diphenylmethane diisocyanate and a modified product of a diphenylmethane diisocyanate, and ester group concentration in the reaction curable polyurethane resin formative composition is within a specific range.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a reaction-curable polyurethane resin-forming composition having excellent wet heat durability, and to a molded article and a coating agent using the resin-forming composition. [Background technology]

[0002] Polyurethane resin compositions have conventionally been used exclusively as compositions using organic solvents, and because they have high adhesion to various materials and various excellent physical properties, they have been widely used as coating agents, paints, adhesives, printing inks, and the like.

[0003] In recent years, there has been a demand for resin compositions that do not use organic solvents in view of social and industrial demands for environmental conservation and work safety.

[0004] As a polyurethane resin composition that does not use such organic solvents, particularly a solvent-free resin composition, for example, a urethane resin composition excellent in mechanical strength and wet heat stability has been proposed (Patent Document 1). However, the resulting composition has a poor texture due to high initial stress, and is not suitable for members that people touch, such as synthetic leather. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-81278 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the background art as described above, and an object of the present invention is to provide a molded article and a coating agent that combine excellent texture, mechanical properties including breaking strength, and moist heat durability, and to provide a reactive curable polyurethane resin-forming composition that is environmentally friendly when producing the molded article and the coating agent. [Means for solving the problem]

[0007] As a result of intensive research into solving the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by making the main component (A) in a reaction-curable polyurethane resin-forming composition contain a multifunctional polyol having a specific structure, and by setting the ester group concentration of the resin-forming composition containing the main component (A) and the curing agent (B) within a specific range, thereby completing the present invention.

[0008] That is, the present invention includes the embodiments shown below.

[0009] [1] A reactive curable polyurethane resin-forming composition comprising a base agent (A) and a curing agent (B), wherein the base agent (A) comprises a multifunctional polyol (a1) and a diol (a2), the multifunctional polyol (a1) being obtained from a polycarbonate diol (p1) and a polyester polyol (p2) having 3 or more hydroxyl functional groups, an average hydroxyl functional group number of 2.3 to 3.5, an average hydroxyl value of 70 to 285 mgKOH / g, and a mass ratio of (p1) to (p2) of (p1) / (p2)=75 / 25 to 55 / 45; the curing agent (B) is at least one selected from the group consisting of diphenylmethane diisocyanate and modified diphenylmethane diisocyanate (b1); and the concentration of ester groups in the reaction curable polyurethane resin-forming composition is 0.10 to 2.00 mmol / g. A reaction-curable polyurethane resin-forming composition comprising:

[0010] [2] The reactive curable polyurethane resin-forming composition according to the above [1], characterized in that the diol (a2) is at least one selected from the group consisting of polycarbonate diols, polyester diols obtained by ring-opening addition polymerization of cyclic ester compounds, and copolymers thereof.

[0011] [3] The reaction curable polyurethane resin-forming composition according to the above [1] or [2], wherein the multifunctional polyol (a1) has a number average molecular weight in the range of 400 to 3,000.

[0012] [4] A reaction curable polyurethane resin-forming composition according to any one of [1] to [3] above, which does not contain an organic solvent.

[0013] [5] A molded article using the reaction curable polyurethane resin forming composition described in any one of [1] to [4] above.

[0014] [6] A coating agent using the reaction curable polyurethane resin forming composition described in any one of [1] to [4] above. Effect of the Invention

[0015] According to the reaction curable polyurethane resin-forming composition of the present invention, it is possible to obtain a molded article and a coating agent that have excellent texture, mechanical properties including breaking strength, and wet heat durability. In addition, it is possible to obtain a reaction curable polyurethane resin-forming composition that is environmentally friendly during the production of the molded article and the coating agent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention relates to a reaction-curable polyurethane resin-forming composition comprising a base agent (A) containing a specific multifunctional polyol (a1) and a diol (a2), and a curing agent (B). In the present invention, unless otherwise specified, the ester group refers to an ester group derived from a carboxylic acid.

[0017] The polyfunctional polyol (a1) in the present invention is obtained from a polycarbonate diol (p1) and a polyester polyol (p2) having 3 or more hydroxyl functional groups.

[0018] Examples of the polycarbonate diol (p1) include those obtainable by reacting carbonates such as dialkyl carbonates (e.g., dimethyl carbonate, diethyl carbonate, etc.), alkylene carbonates (e.g., ethylene carbonate, propylene carbonate, etc.), and diaryl carbonates (e.g., diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate, tetrahydronaphthyl carbonate, etc.) with glycol.

[0019] The glycol is selected from the group of low molecular weight polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, diol dimer acid, ethylene oxide or propylene oxide adduct of bisphenol A, bis(β-hydroxyethyl)benzene, and xylylene glycol. These may be used alone or in combination of two or more.

[0020] As the polyester polyol (p2) having 3 or more hydroxyl functional groups, a polyester polyol obtained from a polyol containing a polyhydric alcohol and a dicarboxylic acid component, or a polyol obtained by ring-opening addition polymerization of a cyclic ester compound such as a lactone using a polyhydric alcohol as an initiator, is preferable.

[0021] Examples of the polyhydric alcohol include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. Bifunctional alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexamethylene glycol, dipropylene glycol, and trimethylene glycol may be used in combination within a range that does not reduce performance. Polyester polyols obtained by a known condensation method of these alcohols and polybasic acids such as oxalic acid, malonic acid, maleic acid, adipic acid, tartaric acid, pimelic acid, sebacic acid, phthalic acid, and terephthalic acid can be used.

[0022] In addition, preferred lactones include, for example, β-propiolactone, β-butyrolactone, γ-butyrolactone, β-valerolactone, γ-valerolactone, δ-valerolactone, α-caprolactone, β-caprolactone, γ-caprolactone, δ-caprolactone, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, 4-methylcaprolactone, γ-caprylolactone, ε-caprylolactone, ε-palmitolactone, etc., and one or more selected from these can be used in combination. Among these, a ring-opening addition polymer of ε-caprolactone using trimethylolpropane as an initiator is preferred from the viewpoints of stability during polymerization and economic efficiency.

[0023] In the present invention, as a component of the multifunctional polyol (a1), a polyester polyol (p3) having an average number of hydroxyl functional groups of 2 or more and less than 3 may be used in combination. In particular, polyester polyols obtained from glycol and dicarboxylic acid components, and polyols obtained by ring-opening addition polymerization of cyclic ester compounds such as lactones using glycol as an initiator are preferred.

[0024] Examples of the glycol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, diol dimer acid, ethylene oxide or propylene oxide adduct of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, and the like. Trimethylolpropane, glycerin, pentaerythritol, sorbitol, and the like can be used in combination. Examples of dicarboxylic acids include polybasic acids such as oxalic acid, malonic acid, maleic acid, adipic acid, tartaric acid, pimelic acid, sebacic acid, phthalic acid, and terephthalic acid.

[0025] In addition, preferred lactones include, for example, β-propiolactone, β-butyrolactone, γ-butyrolactone, β-valerolactone, γ-valerolactone, δ-valerolactone, α-caprolactone, β-caprolactone, γ-caprolactone, δ-caprolactone, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, 4-methylcaprolactone, γ-caprylolactone, ε-caprylolactone, ε-palmitolactone, etc., and one or more selected from these can be used in combination. Among these, a ring-opening addition polymer of ε-caprolactone using ethylene glycol as an initiator is preferred from the standpoint of stability during polymerization and economic efficiency.

[0026] The mass ratio of the polycarbonate diol (p1) to the polyester polyol (p2) having 3 or more hydroxyl functional groups is in the range of (p1) / (p2)=75 / 25 to 55 / 45, and preferably in the range of (p1) / (p2)=70 / 30 to 60 / 40. When a polyester polyol (p3) having an average hydroxyl functional group number of 2 or more and less than 3 is used in combination, the mass ratio is preferably in the range of (p1) / (p2+p3)=75 / 25 to 55 / 45, and more preferably in the range of (p1) / (p2+p3)=70 / 30 to 60 / 40.

[0027] By setting the mass ratio within the above range, a reaction curable polyurethane resin composition having high strength and high elongation mechanical properties can be obtained due to the balance between the cohesive strength of the polycarbonate diol, the urethane group concentration, and the content of the polyester polyol having 3 or more hydroxyl functional groups.

[0028] The multifunctional polyol (a1) may be a simple mixture of the polycarbonate diol (p1) and the polyester polyol (p2), but it may also be a copolymer polyol obtained by transesterification. The same applies when the polyester polyol (p3) is used in combination.

[0029] The average number of hydroxyl functional groups of the polyfunctional polyol (a1) is 2.3 to 3.5, preferably 2.5 to 3.0. If the average number of hydroxyl functional groups is high, the elongation at break in the tensile test tends to decrease, and if the average number of hydroxyl functional groups is low, the strength at break in the tensile test tends to decrease.

[0030] The average hydroxyl value of the polyfunctional polyol (a1) is 70 to 285 mgKOH / g, preferably 90 to 180 mgKOH / g. If the average hydroxyl value is low, the urethane group concentration is low and the strength at break in a tensile test is reduced, whereas if the average hydroxyl value is high, the urethane group concentration is high and the strength at break in a tensile test is improved but the elongation at break tends to be reduced.

[0031] In the present invention, the average number of functional groups is calculated as follows based on the nominal number of functional groups. Average functionality=((number of functional groups of polycarbonate diol (p1)×mol)+(number of functional groups of polyester polyol (p2)×mol)+(number of functional groups of polyester polyol (p3)×mol)) / ((mol of polycarbonate diol (p1))+(mol of polyester polyol (p2))+(mol of polyester polyol (p3)).

[0032] In the present invention, the number average molecular weight of the polycarbonate diol (p1) is preferably from 400 to 5,000, more preferably from 500 to 2,000, in consideration of ease of synthesis and ease of handling.

[0033] The number average molecular weight of the multifunctional polyol (a1) is preferably in the range of 400 to 3,000, and more preferably in the range of 500 to 2,000. By setting it in this range, both excellent texture and wet heat durability can be achieved.

[0034] Examples of the polycarbonate diol (a2) in the present invention include those obtainable by reacting carbonates such as dialkyl carbonates (e.g., dimethyl carbonate, diethyl carbonate, etc.), alkylene carbonates (e.g., ethylene carbonate, propylene carbonate, etc.), and diaryl carbonates (e.g., diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate, tetrahydronaphthyl carbonate, etc.) with the following glycols.

[0035] The glycol is selected from the group of low molecular weight polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, diol dimer acid, ethylene oxide or propylene oxide adduct of bisphenol A, and bis(β-hydroxyethyl)benzene. These may be used alone or in combination of two or more.

[0036] In addition, the diol (a2) in the present invention is preferably at least one selected from the group consisting of polycarbonate diol, polyester diol obtained by ring-opening addition polymerization of a cyclic ester compound, and copolymers thereof. Among these, from the viewpoint of the strength and flexibility of the obtained coating, it is preferable to use a copolymer of polycarbonate diol and polyester diol obtained by ring-opening addition polymerization of a cyclic ester compound. As the cyclic ester compound, the above-mentioned lactones can be preferably used.

[0037] The number average molecular weight of the diol (a2) is preferably 300 to 5,000, more preferably 1,000 to 3,000. If the number average molecular weight is too low, the flexibility of the resulting coating may decrease, and the feel and conformability to the substrate may decrease. On the other hand, if the number average molecular weight is too high, the strength of the coating may become insufficient.

[0038] The curing agent (B) in the present invention is at least one selected from the group consisting of diphenylmethane diisocyanate (hereinafter also referred to as MDI) and modified diphenylmethane diisocyanate (b1). It is preferably a urethane-modified polyisocyanate obtained by urethane-modifying MDI with polycarbonate polyol (b2). Here, the urethane modification refers to the formation of a urethane bond by reacting a hydroxyl group-containing compound with a polyisocyanate.

[0039] The urethane-modified polyisocyanate can be easily obtained by charging MDI and polycarbonate polyol (b2) in a reaction vessel and carrying out a urethane reaction. At this time, the content of isomers (2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate) in the MDI used for preparation is not particularly limited, but is preferably 0.5 to 60 mass% in consideration of availability.

[0040] In the present invention, the isocyanate content of the curing agent (B) is preferably 5.0 to 33.6% by mass, more preferably 10 to 25% by mass. If the isocyanate content is below the lower limit, the viscosity of the resulting urethane-modified polyisocyanate may be high, which may impair workability.

[0041] Furthermore, as the isocyanate that can be used in the curing agent (B) of the present invention, aromatic isocyanates other than MDI, aliphatic isocyanates, alicyclic isocyanates, araliphatic isocyanates, isocyanurate group-containing polyisocyanates obtained using these isocyanates as raw materials, uretdione group-containing polyisocyanates, uretdione group- and isocyanurate group-containing polyisocyanates, urethane group-containing polyisocyanates, allophanate group-containing polyisocyanates, biuret group-containing polyisocyanates, urethimine group-containing polyisocyanates, and the like may be used in combination within a range that does not decrease performance.

[0042] In the present invention, additives can be used in the base agent or the curing agent, or in both. Examples of additives include plasticizers, fillers, colorants, flame retardants, antioxidants, UV absorbers, leveling agents, pigments and dyes, antibacterial agents, and antifungal agents.

[0043] When a cured product is obtained from the reactive curable polyurethane resin-forming composition of the present invention, from the viewpoints of excellent reactive curability, strength and flexibility of the cured product, and suppression of unnecessary foaming, the R value [the number of moles of total isocyanate groups in the curing agent (B) / the number of moles of total hydroxyl groups in the main agent (A)] is preferably 0.8 or more, but from the viewpoint of improving the above-mentioned series of effects, it is more preferable that it is within the range of 0.9 to 5.0, and among these, from the viewpoint of extremely excellent strength and flexibility of the cured product, it is particularly preferable that it is within the range of 1.0 to 1.8.

[0044] The heating temperature during reaction curing is preferably 60 to 180°C. The heating time is preferably 2 minutes to 2 hours. If the temperature is too low or the time is too short, curing may be insufficient. On the other hand, if the temperature is too high or the time is too long, unnecessary heat history may be applied to the cured product or substrate, which may lead to deterioration of the obtained cured product.

[0045] When mixing the base agent (A) and the curing agent (B), a catalyst can be used to shorten the curing process and improve the reaction rate. Examples of the catalyst include urethane-forming reaction catalysts such as tertiary amine catalysts such as triethylamine, tetramethylpropylenediamine, tetramethylhexamethylenediamine, and tolylenediamine, and metal catalysts such as tin-based catalysts such as stannous octoate, stannous oleate, and dibutyltin dilaurate, and these can be used alone or in combination.

[0046] The ester group concentration of the reactive curable polyurethane resin forming composition in the present invention can be calculated as follows. The ester group concentration (mmol / g) of the reactive curable polyurethane resin composition = (ester group concentration (mmol / g) of the multifunctional polyol (a1) x blended mass (g) + ester group concentration (mmol / g) of the polycarbonate diol (a2) x blended mass (g) + ester group concentration (mmol / g) of the curing agent (B) x blended mass (g)) / total blended mass (g). From the viewpoint of strength, flexibility and durability of the cured product obtained from the polyurethane resin forming composition, the ester group concentration of the polyurethane resin forming composition is 0.10 to 2.00 mmol / g, preferably 0.20 to 1.60 mmol / g. If the ester group concentration of the urethane resin forming composition is less than 0.10 mmol / g, the strength of the obtained cured product is reduced. If the ester group concentration is more than 2.00 mmol / g, the durability in a humid and hot environment is reduced.

[0047] Next, a molded body and a coating agent using the reaction curable polyurethane resin forming composition of the present invention will be described. The reaction curable polyurethane resin forming composition of the present invention is used as a molded body and a coating material for electronic device parts such as communication tablets, clothing, furniture and home appliance parts, daily necessities, and automobile parts. The molded body includes parts, structures, films, and sheets, and can be exemplified by those molded by known techniques such as casting and coating.

[0048] The coating agent is a coating film formed on a substrate by mixing a resin for a coating agent containing at least the polyurethane resin-forming composition of the present invention with the above-mentioned crosslinking agent and additives as necessary, stirring the mixture uniformly, and then applying the mixture to a substrate by a known technique such as spray coating, knife coating, wire bar coating, doctor blade coating, reverse roll coating, or calendar coating.

[0049] The substrate may be stainless steel, phosphate-treated steel, galvanized steel, iron, copper, aluminum, brass, glass, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene phthalate resin, polystyrene resin, AS resin, ABS resin, polycarbonate-ABS resin, 6-nylon resin, 6,6-nylon resin, MXD6 nylon resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyurethane resin, phenol resin, melamine resin, polyacetal resin, chlorinated polyolefin resin, polyolefin resin, polyamide resin, polyether ether ketone, etc. Examples of the material include substrates molded from materials such as olefin resins, such as polyethylene resin, polyphenylene sulfide resin, NBR resin, chloroprene resin, SBR resin, SEBS resin, polyethylene, and polypropylene; organic fibers containing at least one type of main component selected from polyethylene terephthalate resin, polytrimethylene terephthalate resin, polybutylene terephthalate resin, polyethylene resin, polypropylene resin, polystyrene resin, 6-nylon resin, 6,6-nylon resin, acrylic resin, polyvinyl alcohol resin, cellulose, polylactic acid, cotton, and wool; inorganic fibers, such as glass wool; and carbon fibers.

[0050] In order to improve the adhesiveness of these substrates, the surfaces of the substrates may be previously subjected to treatments such as corona discharge treatment, frame treatment, ultraviolet irradiation treatment, and ozone treatment. EXAMPLES

[0051] Examples of the present invention will be described below, but the present invention is not limited to these Examples. In the Examples, % and parts are by weight unless otherwise specified.

[0052] [Synthesis of multifunctional polyol 1] 550g of PCD-1, 400g of PCL-1, and 50g of PCL-3 were charged into a reactor equipped with a stirrer, thermometer, heater, and cooler, and the temperature was gradually raised to 190°C under a nitrogen stream. The transesterification reaction was carried out at 190°C for 5 hours to obtain a multifunctional polyol (Polyol-1). The average hydroxyl functionality of Polyol-1 was 2.8, and the hydroxyl value was 145 (mgKOH / g).

[0053] [Synthesis of multifunctional polyol 2] Using the same synthesis method as in Synthesis 1 of polyfunctional polyol, 600 g of PCD-2 and 400 g of PCL-2 were charged and transesterification was carried out at 190°C for 5 hours to obtain a polyfunctional polyol (Polyol-2). The average hydroxyl functionality of Polyol-2 was 2.8, and the hydroxyl value was 250 (mgKOH / g).

[0054] [Synthesis of diol 1] Using the same synthesis method as in Synthesis 1 of polyfunctional polyol, 700 g of PCD-2 and 300 g of PCL-4 were charged and transesterification was carried out at 190°C for 5 hours to obtain a diol (Polyol-3). The average hydroxyl functionality of Polyol-3 was 2.0 and the hydroxyl value was 56 (mgKOH / g).

[0055] [Synthesis of diol 2] Using the same synthesis method as in Synthesis 1 of polyfunctional polyol, 800 g of PCD-2 and 200 g of MPD were charged and transesterification was carried out at 190°C for 5 hours to obtain a diol (Polyol-4). The average hydroxyl functionality of Polyol-4 was 2.0 and the hydroxyl value was 234 (mgKOH / g).

[0056] [Table 1]

[0057] The raw materials used are as follows: (1) PCD-1: 1,6-hexanediol-based polycarbonate diol, number average molecular weight 3,000 (2) PCD-2: 1,6-hexanediol-based polycarbonate diol, number average molecular weight 2,000 (3) PCL-1: Polycaprolactone triol (manufactured by Daicel Corporation, product name: Plaxel 305, number average molecular weight 550) (4) PCL-2: Polycaprolactone triol (manufactured by Daicel Corporation, product name: Plaxel 303, number average molecular weight 300) (5) PCL-3: Polycaprolactone diol (manufactured by Daicel Corporation, trade name: Plaxel 210, number average molecular weight 1,000) (6) PCL-4: Polycaprolactone diol (manufactured by Daicel Corporation, trade name: Plaxel 220, number average molecular weight 2,000) (7) MPD: 3-methyl-1,5-pentanediol (Tokyo Chemical Industry Co., Ltd.).

[0058] [Synthesis of isocyanate prepolymer 1] In a reactor equipped with a stirrer, thermometer, heater, and cooler, 508g of high isomer ratio MDI and 492g of Polyol-3 were charged, and a urethane reaction was carried out at 75℃ for 3 hours under a nitrogen atmosphere to obtain an isocyanate prepolymer (Isocyanate-1). The NCO content of Isocyanate-1 was 15.0%.

[0059] [Synthesis of isocyanate prepolymer 2] Using the same synthesis method as in Synthesis of Isocyanate Prepolymer 1, 575g of high isomer ratio MDI and 425g of PCD-2 were charged and subjected to a urethane reaction at 75°C for 3 hours under a nitrogen atmosphere to obtain an isocyanate prepolymer (Isocyanate-2). The NCO content of Isocyanate-2 was 17.5%.

[0060] [Synthesis of isocyanate prepolymer 3] Using the same synthesis method as in Synthesis of Isocyanate Prepolymer 1, 200g of low isomer ratio MDI, 176g of high isomer ratio MDI, and 624g of PCD-2 were charged and subjected to a urethane reaction at 75°C for 3 hours under a nitrogen atmosphere to obtain an isocyanate prepolymer (Isocyanate-3). The NCO content of Isocyanate-3 was 10.0%.

[0061] [Synthesis of polyisocyanate 1] In a 1L reactor equipped with a stirrer, thermometer, cooler, and nitrogen gas inlet tube, 950g of HDI, 50g of MPD, and 0.1g of zirconium octylate (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were charged, and the reaction was carried out at 110°C for 4 hours. Next, 0.04g of JP-508 (manufactured by Johoku Kagaku Co., Ltd., trade name) was charged into the reactor, and the termination reaction was carried out at 80°C for 1 hour. The isocyanate content of the reaction product after the termination reaction was 40.3%. This reaction product was subjected to thin-film distillation at 130°C and 0.04kPa to obtain polyisocyanate (Isocyanate-4). The isocyanate content of Isocyanate-4 was 19.2%, the viscosity at 25°C was 1800mPa·s, and the free diisocyanate content was 0.1%. In addition, FT-IR and 13 C-NMR analysis confirmed almost no urethane groups or isocyanurate groups.

[0062] [Table 2]

[0063] The raw materials used are as follows: (8) Low isomer ratio MDI: 2,2'-MDI+2,4'-MDI=1.5%, 4,4'-MDI=98.5%, NCO group content=33,6% (9) High isomer ratio MDI: 2,2'-MDI+2,4'-MDI=55.0%, 4,4'-MDI=45.0%, NCO group content=33,6% (10) HDI: hexamethylene diisocyanate (manufactured by Tosoh Corporation).

[0064] [Preparation of polyurethane hardened coating] The base material (A), curing agent (B), and curing catalyst were mixed (unit: grams) as shown in Table 3, and the liquid immediately after mixing was poured onto release paper and cast with a bar coater to give a film with a thickness of 100 μm, cured at 150° C. for 5 minutes, and then aged at 50° C. for 24 hours to obtain a polyurethane coating (film). This film was used as a sample and the following evaluations were carried out.

[0065] [Tensile properties] The tensile properties of the obtained film were measured in accordance with JIS K6251, and the results are shown in Table 3. Test equipment: Tensilon UTA-500 (manufactured by A&D) Measurement conditions: 25℃×50%RH Head speed: 200mm / min ·Dumbbell No. 4.

[0066] [Moisture and heat resistance test] The obtained film was left to stand in a thermostatic chamber controlled at a temperature of 80°C and a relative humidity of 95%. After 400 hours, the film was taken out and the tensile properties were measured according to JIS K6251. The property retention was calculated from the measured values ​​of the strength at break before and after leaving the film under the humid heat conditions.

[0067]

number

[0068] [Evaluation criteria for polyurethane cured films] The properties of the cured film are considered to be good if the 100% modulus before the durability test is 0.5-5.0 MPa, the strength at break is 30 MPa or greater, and the strength retention at break after the moist heat resistance test is 60% or greater.

[0069] [Table 3]

[0070] The raw materials used are as follows: (11) Polyol-5: A copolymer polycarbonate diol of 3-methyl-1,5-pentanediol / 1,6-hexanediol = 5 / 5 (molar ratio), number average molecular weight 2,000 (12) PCL-5: Polycaprolactone triol (manufactured by Daicel Corporation, trade name: Plaxel 320, number average molecular weight 2,000) (13) DOTDL: Dioctyltin dilaurate (Kishida Chemical Co., Ltd.) (14) BYK-331: Polyether-modified polydimethylsiloxane (manufactured by BYK Chemie)

Claims

1. A reactive curable polyurethane resin-forming composition comprising a base agent (A) and a curing agent (B), wherein the base agent (A) comprises a multifunctional polyol (a1) and a diol (a2), the multifunctional polyol (a1) being obtained from a polycarbonate diol (p1) and a polyester polyol (p2) having 3 or more hydroxyl functional groups, an average hydroxyl functional group number of 2.3 to 3.5, an average hydroxyl value of 70 to 285 mgKOH / g, and a mass ratio of (p1) to (p2) of (p1) / (p2)=75 / 25 to 55 / 45; The curing agent (B) is at least one selected from the group consisting of diphenylmethane diisocyanate and modified diphenylmethane diisocyanate (b1); and the concentration of ester groups in the reaction-curable polyurethane resin-forming composition is 0.10 to 2.00 mmol / g. A reaction-curable polyurethane resin-forming composition comprising:

2. 2. The reaction curable polyurethane resin-forming composition according to claim 1, wherein the diol (a2) is at least one selected from the group consisting of polycarbonate diols, polyester diols obtained by ring-opening addition polymerization of cyclic ester compounds, and copolymers thereof.

3. 3. The reaction-curable polyurethane resin-forming composition according to claim 1, wherein the multifunctional polyol (a1) has a number average molecular weight in the range of 400 to 3,000.

4. 4. The reaction-curable polyurethane resin-forming composition according to claim 1, which does not contain an organic solvent.

5. A molded article using the reaction curable polyurethane resin forming composition according to any one of claims 1 to 4.

6. A coating agent using the reaction curable polyurethane resin forming composition according to any one of claims 1 to 4.

Images