Polyurethane resin composition, resin cured material, and, cast polyurethane elastomer

Abstract

To provide a polyurethane resin composition capable of obtaining a resin cured material with excellent hardness, productivity and appearance, a resin cure material and a cast polyurethane elastomer.SOLUTION: A polyurethane resin composition contains a polyisocyanate component (A), a component containing active hydrogen groups (B), and a urethanization catalyst (C). The polyisocyanate component (A) includes an isocyanurate derivative of aliphatic polyisocyanate. The component containing active hydrogen groups (B) includes polycarbonate polyol (B1) and polyether polyol (B2). The number average molecular weight of polyether polyol (B2) is between 200 and 500. The average hydroxyl number of polyether polyol (B2) is 3 or more. The content ratio of polyether polyol (B2) is between 30% and 70%. The urethanization catalyst (C) contains at least one selected from the group consisting of Ti-based catalysts, Zn-based catalysts, Zr-based catalysts, and Bi-based catalysts.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyurethane resin composition, a cured resin, and a cast polyurethane elastomer. [Background technology]

[0002] Cast polyurethane elastomers have been widely used in various industrial fields due to their excellent mechanical properties. For example, cast polyurethane elastomers are used in the optical field due to their excellent mechanical properties and appearance (transparency).

[0003] More specifically, a polyurethane resin obtained by the following method has been proposed. Specifically, in this method, a modified aliphatic polyisocyanate, an aliphatic polyisocyanate monomer, and polycaprolactone triol (average hydroxyl value 539 mgKOH / g) are first mixed in an equivalent ratio (NCO / OH) of 1.0. A bismuth-based urethanization catalyst is then added to the mixture, and the mixture is heated in a mold. This produces a polyurethane resin (see, for example, Patent Document 1 (Example 10)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-12141 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, in the above-mentioned method, a modified aliphatic polyisocyanate and a monomer of the aliphatic polyisocyanate are used in combination. In such a case, the operations for producing the polyurethane resin are complicated. Therefore, further improvement in productivity is required.

[0006] As a method for improving productivity, for example, the use of only modified aliphatic polyisocyanates without using a monomer of the aliphatic polyisocyanate has been considered.

[0007] However, when the above method does not use an aliphatic polyisocyanate monomer, i.e., when a modified aliphatic polyisocyanate is reacted with polycaprolactone triol (average hydroxyl value 539 mgKOH / g) in the presence of a bismuth-based urethanization catalyst, molding stability may be insufficient, resulting in sink marks (mold shrinkage) and / or bubbles, which may reduce the appearance (transparency) of the polyurethane resin.

[0008] The present invention relates to a polyurethane resin composition that can give a cured resin product that combines excellent mechanical properties, productivity, and appearance, a cured resin product obtained using the polyurethane resin composition, and a cast polyurethane elastomer. [Means for solving the problem]

[0009] The present invention [1] is a polyurethane resin composition containing a polyisocyanate component (A), an active hydrogen group-containing component (B), and a urethanization catalyst (C), in which the polyisocyanate component (A) contains an isocyanurate derivative of an aliphatic polyisocyanate, the active hydrogen group-containing component (B) contains a polycarbonate polyol (B1) and a polyether polyol (B2), the number average molecular weight of the polyether polyol (B2) is 200 or more and 500 or less, the average number of hydroxyl groups of the polyether polyol (B2) is 3.0 or more, the content of the polyether polyol (B2) is 30% by mass or more and 70% by mass or less, based on the total amount of the polycarbonate polyol (B1) and the polyether polyol (B2), and the urethanization catalyst (C) contains at least one catalyst selected from the group consisting of a Ti-based catalyst, a Zn-based catalyst, a Zr-based catalyst, and a Bi-based catalyst.

[0010] The present invention [2] includes the polyurethane resin composition according to the above [1], wherein the viscosity (60°C) of the polycarbonate polyol (B1) is 3000 mPa·s or more and 50000 mPa·s or less.

[0011] The present invention [3] includes the polyurethane resin composition according to the above [1] or [2], wherein the viscosity (80°C) of the active hydrogen group-containing component (B) is 30 mPa·s or more and 900 mPa·s or less.

[0012] The present invention [4] includes the polyurethane resin composition according to any one of the above [1] to [3], wherein the aliphatic polyisocyanate contains a chain aliphatic polyisocyanate.

[0013] The present invention [5] includes the polyurethane resin composition according to any one of the above [1] to [4], wherein the aliphatic polyisocyanate contains pentamethylene diisocyanate.

[0014] The present invention [6] includes the polyurethane resin composition according to any one of the above [1] to [5], wherein the polycarbonate polyol (B1) contains a plant-derived polycarbonate polyol.

[0015] The present invention [7] includes a cured resin product containing a cured product of the polyurethane resin composition according to any one of the above [1] to [6].

[0016] The present invention [8] includes a cast polyurethane elastomer containing the cured resin described in [7] above. [Effects of the Invention]

[0017] In the polyurethane resin composition of the present invention, the active hydrogen group-containing component (B) contains a polycarbonate polyol (B1) and a polyether polyol (B2). The polyether polyol (B2) has a predetermined number-average molecular weight and a predetermined average number of hydroxyl groups. The content ratio of the polycarbonate polyol (B1) to the polyether polyol (B2) is adjusted. Furthermore, the urethanization catalyst (C) contains a predetermined catalyst.

[0018] Therefore, the polyurethane resin composition can provide a cured resin product that has excellent mechanical properties, productivity, and appearance.

[0019] Furthermore, the cured resin and cast polyurethane elastomer of the present invention are obtained using the polyurethane resin composition described above, and therefore the cured resin and cast polyurethane elastomer have excellent mechanical properties, productivity, and appearance. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1. Polyurethane resin composition The polyurethane resin composition contains a polyisocyanate component (A), an active hydrogen group-containing component (B), and a urethanization catalyst (C). Preferably, the polyurethane resin composition comprises the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0021] (1) Polyisocyanate component (A) The polyisocyanate component (A) is a component containing two or more isocyanate groups in the molecule. The polyisocyanate component (A) contains an isocyanurate derivative of an aliphatic polyisocyanate. From the viewpoints of productivity and mechanical properties of the cured resin (described below), the polyisocyanate component (A) is composed of an isocyanurate derivative of an aliphatic polyisocyanate.

[0022] Examples of the aliphatic polyisocyanate include aliphatic diisocyanates, such as linear aliphatic diisocyanates and alicyclic diisocyanates.

[0023] Examples of the chain aliphatic diisocyanate include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), and hexamethylene diisocyanate (HDI). Examples of the alicyclic diisocyanate include isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), methylenebis(cyclohexyl isocyanate) (HDI), and cyclohexanediisocyanate (HDI). 12 MDI) and bis(isocyanatomethyl)cyclohexane (H6XDI). These can be used alone or in combination of two or more.

[0024] From the viewpoints of the appearance, mechanical properties, and molding stability of the cured resin (described later), the aliphatic polyisocyanate is preferably an aliphatic diisocyanate, more preferably a chain aliphatic diisocyanate, even more preferably pentamethylene diisocyanate (PDI) and hexamethylene diisocyanate (HDI), and particularly preferably pentamethylene diisocyanate (PDI).

[0025] That is, from the viewpoints of the appearance, mechanical properties, and molding stability of the cured resin (described later), the aliphatic polyisocyanate preferably contains an aliphatic diisocyanate, more preferably contains a chain aliphatic diisocyanate, even more preferably contains pentamethylene diisocyanate (PDI) and / or hexamethylene diisocyanate (HDI), and particularly preferably contains pentamethylene diisocyanate (PDI).

[0026] Examples of pentamethylene diisocyanate (PDI) include petroleum-derived pentamethylene diisocyanate (PDI) and plant-derived pentamethylene diisocyanate (PDI), and plant-derived pentamethylene diisocyanate (PDI) is preferred. By using plant-derived pentamethylene diisocyanate (PDI), a polyurethane resin composition with excellent environmental friendliness can be obtained.

[0027] The method for producing the isocyanurate derivative of aliphatic polyisocyanate is not particularly limited. Examples of the method for producing the isocyanurate derivative of aliphatic polyisocyanate include the methods described in

[0030] to

[0087] of JP 2019-203061 A.

[0028] More specifically, isocyanurate derivatives of aliphatic polyisocyanates are produced, for example, by subjecting the above-mentioned aliphatic polyisocyanates to an isocyanuration reaction in the presence of an isocyanuration catalyst. Alternatively, isocyanurate derivatives of aliphatic polyisocyanates can be produced, for example, by subjecting the above-mentioned aliphatic polyisocyanates to a urethanization reaction with alcohols, and then subjecting the resulting reaction product to an isocyanuration reaction in the presence of an isocyanuration catalyst.

[0029] The isocyanurate derivative of aliphatic polyisocyanate is available as a commercially available product, such as Takenate D-170N (trade name, isocyanurate derivative of hexamethylene diisocyanate (HDI), isocyanate group content 20.7%, solid content 100% by mass, manufactured by Mitsui Chemicals), Stabio D-370N (trade name, isocyanurate derivative of pentamethylene diisocyanate (PDI), isocyanate group content 25% by mass, solid content 100% by mass, manufactured by Mitsui Chemicals), Takenate D-127N (trade name: isocyanurate derivative of bis(isocyanatomethyl)cyclohexane (H6XDI), isocyanate group content 13.5% by mass, solid content 75% by mass, ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.), and Takenate D-140N (trade name: isocyanurate derivative of isophorone diisocyanate (IPDI), isocyanate group content 10.5% by mass, solid content 75% by mass, ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.).

[0030] The isocyanurate derivatives of aliphatic polyisocyanates can be used alone or in combination of two or more. As the isocyanurate derivatives of aliphatic polyisocyanates, preferably, an isocyanurate derivative of an aliphatic diisocyanate is used, more preferably, an isocyanurate derivative of a chain aliphatic diisocyanate is used, even more preferably, an isocyanurate derivative of pentamethylene diisocyanate (PDI) and an isocyanurate derivative of hexamethylene diisocyanate (HDI) are used, still more preferably, an isocyanurate derivative of pentamethylene diisocyanate (PDI) is used, and particularly preferably, an isocyanurate derivative of plant-derived pentamethylene diisocyanate (PDI) is used.

[0031] The polyisocyanate component (A) may contain other polyisocyanate compounds as unavoidable components. The other polyisocyanate compounds are polyisocyanate compounds excluding isocyanurate derivatives of aliphatic polyisocyanates.

[0032] The inevitable components are trace components inevitably contained in the polyisocyanate component (A). Examples of other polyisocyanate compounds include aliphatic polyisocyanate monomers (unreacted raw materials) and aliphatic polyisocyanate allophanate derivatives (by-products).

[0033] The content of unavoidable components (other polyisocyanate compounds) relative to the total amount of the polyisocyanate component (A) is, for example, 10 mass% or less, preferably 5 mass% or less, more preferably 1 mass% or less, and usually 0 mass% or more.

[0034] The content of the polyisocyanate component (A) in the polyurethane resin composition is not particularly limited, but is adjusted based on the equivalent ratio (NCO / active hydrogen group) of the isocyanate groups in the polyisocyanate component (A) to the active hydrogen groups in the active hydrogen group-containing component (B), as will be described in detail later.

[0035] (2) Active hydrogen group-containing component (B) The active hydrogen group-containing component (B) is a component containing one or more active hydrogen groups in the molecule. Examples of the active hydrogen group include a hydroxyl group and an amino group, and preferably a hydroxyl group. The active hydrogen group-containing component (B) contains, as essential components, a polycarbonate polyol (B1) and a polyether polyol (B2).

[0036] Examples of the polycarbonate polyol (B1) include ring-opening polymers of cyclic carbonates using low-molecular-weight polyols as initiators.

[0037] Low-molecular-weight polyols are organic compounds with relatively low molecular weights, each having two or more hydroxyl groups in its molecule. The molecular weight of a low-molecular-weight polyol is, for example, 40 or more, and, for example, 200 or less. Examples of low-molecular-weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include linear dihydric alcohols and branched dihydric alcohols. Examples of linear dihydric alcohols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol. Examples of branched dihydric alcohols include 1,2-propanediol, 1,3-butanediol, 1,2-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. These can be used alone or in combination of two or more.

[0038] Examples of cyclic carbonates include ethylene carbonate and propylene carbonate, which can be used alone or in combination of two or more.

[0039] The method for ring-opening polymerization of a cyclic carbonate using a low-molecular-weight polyol as an initiator is not particularly limited, and any known method can be used. If necessary, the ring-opening polymer may be modified with the above-mentioned low-molecular-weight polyol (preferably a branched dihydric alcohol).

[0040] Moreover, examples of the polycarbonate polyol (B1) include reaction products of the above-mentioned low-molecular-weight polyols and chain carbonate compounds.

[0041] Examples of the chain carbonate compound include dimethyl carbonate and diethyl carbonate, which can be used alone or in combination of two or more.

[0042] The method for reacting the low-molecular-weight polyol with the linear carbonate is not particularly limited, and any known method can be used. Furthermore, the reaction product may be modified with the above-mentioned low-molecular-weight polyol (preferably a branched dihydric alcohol) as needed.

[0043] Furthermore, examples of the polycarbonate polyol (B1) include plant-derived polycarbonate polyols derived from plant-derived raw materials (e.g., isosorbide). The method for producing the plant-derived polycarbonate polyol is not particularly limited, and known methods can be used.

[0044] The polycarbonate polyol (B1) can be used alone or in combination of two or more kinds. As the polycarbonate polyol (B1), a plant-derived polycarbonate polyol is preferably used. That is, the polycarbonate polyol (B1) preferably contains a plant-derived polycarbonate polyol. By using a plant-derived polycarbonate polyol, a polyurethane resin composition having excellent environmental friendliness can be obtained.

[0045] The number average molecular weight of the polycarbonate polyol (B1) is, for example, 500 or more, preferably 600 or more, more preferably 700 or more, and even more preferably 800 or more. The number average molecular weight of the polycarbonate polyol (B1) is, for example, 2000 or less, preferably 1500 or less, more preferably 1200 or less, and even more preferably 1000 or less. The number average molecular weight can be calculated from the hydroxyl group equivalent weight and the average number of hydroxyl groups by a known method. The number average molecular weight can be measured as a polystyrene-equivalent molecular weight by gel permeation chromatography (the same applies hereinafter).

[0046] The polycarbonate polyol (B1) may be a crystalline polycarbonate polyol or an amorphous polycarbonate polyol, preferably an amorphous polycarbonate polyol. The crystalline polycarbonate polyol is a polycarbonate polyol that is in a solid state at 25°C. The amorphous polycarbonate polyol is a polycarbonate polyol that is in a liquid state at 25°C.

[0047] The average number of hydroxyl groups in the polycarbonate polyol (B1) is, for example, 2.0 or more. The average number of hydroxyl groups in the polycarbonate polyol (B1) is, for example, 4.0 or less, preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.5 or less. The average number of hydroxyl groups in the polycarbonate polyol (B1) is particularly preferably 2.0.

[0048] The viscosity (60°C) of the polycarbonate polyol (B1) is, from the viewpoints of the appearance and molding stability of the cured resin (described below), for example, 1000 mPa·s or more, preferably 3000 mPa·s or more, and more preferably 5000 mPa·s or more. Furthermore, from the viewpoints of the appearance and mechanical properties of the cured resin (described below), the viscosity (60°C) of the polycarbonate polyol (B1) is, for example, 80000 mPa·s or less, preferably 50000 mPa·s or less, more preferably 30000 mPa·s or less, and even more preferably 15000 mPa·s or less. The viscosity (60°C) may be the catalog value of a commercially available polycarbonate polyol (B1). The viscosity (60°C) can also be measured at 60°C using the same method as the viscosity (80°C) measurement method described below.

[0049] Examples of polyether polyols (B2) include polyoxyalkylene (C2-3) polyols and polytetramethylene ether polyols. Examples of polyoxyalkylene (C2-3) polyols include polyoxyethylene polyols, polyoxypropylene polyols, polyoxytriethylene polyols, and polyoxyethylene-polyoxypropylene polyols (random or block copolymers). Examples of polytetramethylene ether polyols include crystalline polytetramethylene ether glycols and amorphous polytetramethylene ether glycols. These may be used alone or in combination of two or more. Examples of polyether polyols include preferably polyoxyalkylene (C2-3) polyols, more preferably polyoxypropylene polyols.

[0050] The number average molecular weight of the polyether polyol (B2) is, from the viewpoints of the appearance and mechanical properties of the cured resin (described later), at least 200, preferably at least 250, and more preferably at least 300. The number average molecular weight of the polyether polyol (B2) is, from the viewpoints of compatibility with the active hydrogen group-containing component (B) and the mechanical properties of the cured resin (described later), at most 500, preferably at most 450, more preferably at most 400, and even more preferably at most 350.

[0051] The average number of hydroxyl groups in the polyether polyol (B2) is 3.0 or more from the viewpoint of the mechanical properties of the cured resin (described later). The average number of hydroxyl groups in the polyether polyol (B2) is, for example, 6.0 or less, preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.5 or less. The average number of hydroxyl groups in the polyether polyol (B2) is particularly preferably 3.0.

[0052] The viscosity (60°C) of the polyether polyol (B2) is, from the viewpoints of the appearance and molding stability of the cured resin (described below), for example, 5 mPa·s or more, preferably 10 mPa·s or more. Furthermore, from the viewpoints of the appearance and mechanical properties of the cured resin (described below), the viscosity (60°C) of the polyether polyol (B2) is, for example, 1000 mPa·s or less, preferably 500 mPa·s or less. The viscosity (60°C) may be the catalog value of a commercially available polyether polyol (B2). The viscosity (60°C) can also be measured in a 60°C environment using a method similar to the method for measuring the viscosity (80°C) described below.

[0053] The active hydrogen group-containing component (B) may optionally contain other polyol compounds, if necessary. The other polyol compounds are polyol compounds other than the polycarbonate polyol (B1) and the polyether polyol (B2).

[0054] Examples of other polyol compounds include the low-molecular-weight polyols described above. Examples of other polyol compounds include high-molecular-weight polyols (excluding polycarbonate polyols and polyether polyols). Examples of high-molecular-weight polyols (excluding polycarbonate polyols and polyether polyols) include polyester polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. These can be used alone or in combination of two or more.

[0055] The content ratio of the other polyol compounds is appropriately set depending on the purpose and application. More specifically, the content ratio of the other polyol compounds is, for example, 50 mass% or less, preferably 30 mass% or less, more preferably 10 mass% or less, and particularly preferably 0 mass% relative to the total amount of the active hydrogen group-containing component (B).

[0056] That is, the sum of the content of the polycarbonate polyol (B1) and the content of the polyether polyol (B2) is, for example, 50 mass% or more, preferably 70 mass% or more, more preferably 90 mass% or less, and particularly preferably 100 mass% based on the total amount of the active hydrogen group-containing component (B). In other words, the active hydrogen group-containing component (B) preferably consists of the polycarbonate polyol (B1) and the polyether polyol (B2).

[0057] The content ratio of the polycarbonate polyol (B1) and the content ratio of the polyether polyol (B2) are set, for example, from the viewpoint of improving the productivity, mechanical properties, and appearance of the cured resin (described later).

[0058] More specifically, the content of the polycarbonate polyol (B1) is 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on the total amount of the polycarbonate polyol (B1) and the polyether polyol (B2), from the viewpoints of productivity and appearance. Also, the content of the polycarbonate polyol (B1) is 70% by mass or less, preferably 65% by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less, based on the total amount of the polycarbonate polyol (B1) and the polyether polyol (B2), from the viewpoints of productivity and appearance.

[0059] In other words, the content of polyether polyol (B2) is 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on the total amount of polycarbonate polyol (B1) and polyether polyol (B2), from the viewpoints of productivity and appearance of the cured resin material (described later). Also, the content of polyether polyol (B2) is 70% by mass or less, preferably 65% by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less, based on the total amount of polycarbonate polyol (B1) and polyether polyol (B2), from the viewpoints of productivity and appearance of the cured resin material (described later).

[0060] By adjusting the content ratio of the polycarbonate polyol (B1) and the content ratio of the polyether polyol (B2), for example, the viscosity and compatibility of the active hydrogen group-containing component (B) can be adjusted, and a cured resin product (described below) having excellent mechanical properties and appearance can be efficiently produced.

[0061] The viscosity (80°C) of the active hydrogen group-containing component (B) is, from the viewpoints of productivity and appearance of the cured resin (described below), for example, 30 mPa·s or more, preferably 50 mPa·s or more, more preferably 100 mPa·s or more, and even more preferably 150 mPa·s or more. The viscosity (80°C) of the active hydrogen group-containing component (B) is, from the viewpoints of productivity and appearance of the cured resin (described below), for example, 900 mPa·s or less, preferably 600 mPa·s or less, more preferably 400 mPa·s or less, and even more preferably 200 mPa·s or less. The viscosity (80°C) is measured in accordance with the examples described below (the same applies hereinafter).

[0062] The content of the active hydrogen group-containing component (B) in the polyurethane resin composition is not particularly limited, but is adjusted based on the equivalent ratio (NCO / active hydrogen group) of the isocyanate groups in the polyisocyanate component (A) to the active hydrogen groups in the active hydrogen group-containing component (B), as described in detail below.

[0063] (2) Urethane catalyst (C) The urethanization catalyst (C) contains at least one selected from the group consisting of a Ti (titanium)-based catalyst, a Zn (zinc)-based catalyst, a Zr (zirconium)-based catalyst, and a Bi (bismuth)-based catalyst. Preferably, the urethanization catalyst (C) is at least one selected from the group consisting of a Ti-based catalyst, a Zn-based catalyst, a Zr-based catalyst, and a Bi-based catalyst.

[0064] Examples of Ti-based catalysts include titanium 2-ethylhexoxide and titanium ethylacetoacetate. Ti-based catalysts are also available as commercially available products. Examples of commercially available products include Orgatix TC-750 (trade name, manufactured by Matsumoto Fine Chemicals). These catalysts can be used alone or in combination of two or more.

[0065] An example of a Zn-based catalyst is zinc octylate. Also, Zn-based catalysts are commercially available. Examples of commercially available products include K-KAT XK-661 (trade name, manufactured by KING INDUSTRIES), K-KAT XK-614 (trade name, manufactured by KING INDUSTRIES), and K-KAT XK-635 (trade name, manufactured by KING INDUSTRIES). These can be used alone or in combination of two or more types.

[0066] An example of a Zr-based catalyst is zirconium tetraacetylacetonate. Furthermore, Zr-based catalysts are commercially available. Examples of commercially available products include K-KAT 4205 (trade name, zirconium complex, manufactured by KING INDUSTRIES), K-KAT 6212 (trade name, zirconium complex, manufactured by KING INDUSTRIES), and K-KAT A209 (trade name, zirconium complex, manufactured by KING INDUSTRIES). These may be used alone or in combination of two or more types.

[0067] Examples of Bi-based catalysts include bismuth octoate and bismuth 2-ethylhexanoate. Bi-based catalysts are also commercially available. Examples of commercially available products include K-KAT 348 (trade name, bismuth carboxylate, manufactured by KING INDUSTRIES), K-KAT XC-C227 (trade name, bismuth carboxylate, manufactured by KING INDUSTRIES), K-KAT XK628 (trade name, bismuth carboxylate, manufactured by KING INDUSTRIES), and K-KAT XK640 (trade name, bismuth carboxylate, manufactured by KING INDUSTRIES). These catalysts can be used alone or in combination of two or more.

[0068] The urethanization catalyst (C) can be used alone or in combination of two or more kinds. From the viewpoint of the appearance and molding stability of the cured resin (described later), a Zr-based catalyst is preferably used as the urethanization catalyst (C). More specifically, the urethanization catalyst (C) preferably contains a Zr-based catalyst, and more preferably consists of a Zr-based catalyst.

[0069] The content of the urethanization catalyst (C) is adjusted depending on the type of the urethanization catalyst (C), as will be described in detail later.

[0070] The urethanization catalyst (C) has a relatively low activity, and therefore the reaction rate of the polyurethane resin composition can be adjusted, and a cured resin product (described below) with excellent appearance and molding stability can be obtained.

[0071] Furthermore, from the viewpoint of the appearance and molding stability of the cured resin (described later), the urethanization catalyst (C) preferably does not contain a catalyst having a relatively high activity. Examples of catalysts having a relatively high activity include Sn-based catalysts and amine-based catalysts. That is, the urethanization catalyst (C) preferably does not contain a Sn-based catalyst or an amine-based catalyst. Examples of Sn-based catalysts include dibutyltin dilaurate (DBTDL) and stannous octoate (SO). Examples of amine-based catalysts include tertiary amines, quaternary ammonium salts, and imidazole compounds.

[0072] If the urethanization catalyst (C) does not contain a catalyst having a relatively high activity, it is possible, among other things, to adjust the curing rate of the polyurethane resin composition, obtain excellent molding stability, and obtain a cured resin product (described below) having excellent appearance.

[0073] (4) Other ingredients The polyurethane resin composition may contain known additives as needed. Examples of additives include antioxidants, heat stabilizers, UV absorbers, light stabilizers, antiblocking agents, release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0074] (5) Method for producing polyurethane resin composition The polyurethane resin composition is, for example, a mixture of a polyisocyanate component (A), an active hydrogen group-containing component (B), and a urethanization catalyst (C). The polyurethane resin composition is produced by mixing the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) by a known method.

[0075] The method for mixing the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) is not particularly limited. For example, the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) may be mixed all at once. Alternatively, the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) may be mixed sequentially. Preferably, the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) are mixed sequentially.

[0076] The mixing order in the sequential mixing is not particularly limited. For example, the active hydrogen group-containing component (B) and the urethanization catalyst (C) may be mixed first, and then the mixture of the active hydrogen group-containing component (B) and the urethanization catalyst (C) may be mixed with the polyisocyanate component (A). Alternatively, for example, the polyisocyanate component (A) and the urethanization catalyst (C) may be mixed first, and then the mixture of the polyisocyanate component (A) and the urethanization catalyst (C) may be mixed with the active hydrogen group-containing component (B). Preferably, the active hydrogen group-containing component (B) and the urethanization catalyst (C) are mixed first, and then the mixture of the active hydrogen group-containing component (B) and the urethanization catalyst (C) is mixed with the polyisocyanate component (A).

[0077] More specifically, in this method, first, the active hydrogen group-containing component (B) is prepared. That is, the polycarbonate polyol (B1) and the polyether polyol (B2) are mixed in the above-mentioned ratio. This prepares the active hydrogen group-containing component (B).

[0078] The method for mixing the polycarbonate polyol (B1) and the polyether polyol (B2) is not particularly limited. For example, first, the polycarbonate polyol (B1) and the polyether polyol (B2) are each heated to reduce their viscosity. Then, the polycarbonate polyol (B1) and the polyether polyol (B2) are mixed in a low-viscosity state. This produces the active hydrogen group-containing component (B) as a mixture (primary mixture) of the polycarbonate polyol (B1) and the polyether polyol (B2). The active hydrogen group-containing component (B) is subjected to a degassing treatment, if necessary.

[0079] Next, in this method, the active hydrogen group-containing component (B) is mixed with the urethanization catalyst (C). More specifically, the urethanization catalyst (C) is added to the active hydrogen group-containing component (B). The amount of the urethanization catalyst (C) added is not particularly limited, but is adjusted, for example, depending on the type of the urethanization catalyst (C).

[0080] For example, when a Ti-based catalyst is used alone, the content of the Ti-based catalyst is, for example, 100 ppm or more, preferably 300 ppm or more, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C). The content of the Ti-based catalyst is, for example, 1000 ppm or less, preferably 800 ppm or less, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0081] When a Zn-based catalyst is used alone, the content of the Zn-based catalyst is, for example, 50 ppm or more, preferably 100 ppm or more, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).The content of the Zn-based catalyst is, for example, 500 ppm or less, preferably 300 ppm or less, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0082] Furthermore, for example, when a Zr-based catalyst is used alone, the content of the Zr-based catalyst is, for example, 100 ppm or more, preferably 300 ppm or more, relative to the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).The content of the Zr-based catalyst is, for example, 1000 ppm or less, preferably 800 ppm or less, relative to the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0083] When a Bi catalyst is used alone, the content of the Bi catalyst is, for example, 50 ppm or more, preferably 100 ppm or more, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).The content of the Bi catalyst is, for example, 500 ppm or less, preferably 300 ppm or less, based on the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0084] The total content of the urethanization catalyst (C) relative to the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) is, for example, 50 ppm or more, preferably 100 ppm or more, and the total content of the urethanization catalyst (C) relative to the total amount of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C) is, for example, 1000 ppm or less, preferably 800 ppm or less.

[0085] In this method, the urethanization catalyst (C) and the active hydrogen group-containing component (B) added in the above ratio are mixed by a known method. This produces a mixture (secondary mixture) of the active hydrogen group-containing component (B) and the urethanization catalyst (C). The mixture (secondary mixture) is then degassed, if necessary.

[0086] Next, in this method, the mixture (secondary mixture) of the active hydrogen group-containing component (B) and the urethanization catalyst (C) is mixed with the polyisocyanate component (A). The mixing ratio is adjusted, for example, so that the equivalent ratio (NCO / active hydrogen groups) of the isocyanate groups in the polyisocyanate component (A) to the active hydrogen groups in the active hydrogen group-containing component (B) falls within a predetermined range.

[0087] For example, from the viewpoints of the appearance and molding stability of the cured resin product (described later), the equivalent ratio of the isocyanate groups in the polyisocyanate component (A) to the active hydrogen groups in the active hydrogen group-containing component (B) (NCO / active hydrogen groups) is, for example, 0.8 or more, preferably 0.9 or more, more preferably 1.0 or more, even more preferably 1.01 or more, and particularly preferably 1.05 or more. Also, from the viewpoints of the appearance and molding stability of the cured resin product (described later), the equivalent ratio of the isocyanate groups in the polyisocyanate component (A) to the active hydrogen groups in the active hydrogen group-containing component (B) (NCO / active hydrogen groups) is, for example, 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and particularly preferably 1.1 or less.

[0088] The mixing method is not particularly limited. For example, a mixture (secondary mixture) of the active hydrogen group-containing component (B) and the urethanization catalyst and the polyisocyanate component (A) are preheated to reduce the viscosity. Then, the mixture (secondary mixture) of the active hydrogen group-containing component (B) and the urethanization catalyst and the polyisocyanate component (A) are mixed in a low-viscosity state.

[0089] As a result, a polyurethane resin composition is obtained as a mixture (tertiary mixture) of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C).

[0090] (6) Effects In the polyurethane resin composition, the active hydrogen group-containing component (B) contains a polycarbonate polyol (B1) and a polyether polyol (B2). The polyether polyol (B2) has a predetermined number-average molecular weight and a predetermined average number of hydroxyl groups. The content ratio of the polycarbonate polyol (B1) to the polyether polyol (B2) is adjusted. The urethanization catalyst (C) contains a predetermined catalyst.

[0091] Therefore, the polyurethane resin composition can provide a cured resin product that has excellent mechanical properties, productivity, and appearance.

[0092] 2. Resin cured products and cast polyurethane elastomers (1) Cured resin product The cured resin product is, for example, an elastic molded product, and is preferably a polyurethane elastomer. The cured resin product contains, and preferably consists of, the cured product of the polyurethane resin composition described above.

[0093] The cured resin (polyurethane elastomer) is produced, for example, as a TPU (thermoplastic polyurethane resin) or a TSU (thermosetting polyurethane resin). Preferably, the cured resin (polyurethane elastomer) is produced as a TPU (thermoplastic polyurethane resin). The cured resin (polyurethane elastomer) is molded by a known molding method.

[0094] Examples of molding methods include cast molding, thermocompression molding, injection molding, extrusion molding, and melt spinning. Molded products of polyurethane elastomers are articles that independently have a predetermined shape depending on the purpose and application, and are distinguished from coating agents that are applied to substrates. Examples of shapes of polyurethane elastomers include pellets, plates, fibers, strands, films, sheets, pipes, bottles, hollow bodies, boxes, and buttons.

[0095] A preferred molding method is cast molding. A cast polyurethane elastomer is obtained by cast molding. That is, the cast polyurethane elastomer contains the above-mentioned cured resin, and preferably consists of the above-mentioned cured resin.

[0096] (2) Cast polyurethane elastomer The method for obtaining the cast polyurethane elastomer is not particularly limited, and a known cast molding method can be used. For example, the polyurethane resin composition (a mixture of the polyisocyanate component (A), the active hydrogen group-containing component (B), and the urethanization catalyst (C)) is degassed as necessary.

[0097] The polyurethane resin composition is then poured into a preheated mold having a desired shape. Examples of the mold include a resin mold and a metal mold, and from the viewpoint of moldability, a metal mold is preferred.

[0098] In this method, the polyurethane resin composition is heated in a mold to cause a urethane reaction between the polyisocyanate component (A) and the active hydrogen group-containing component (B), which then hardens the polyurethane resin composition to produce a cast polyurethane elastomer (cured resin).

[0099] The curing conditions are not particularly limited. The curing temperature is, for example, 20°C or higher, preferably 40°C or higher, and more preferably 60°C or higher. The curing temperature is, for example, 200°C or lower, preferably 180°C or lower, and more preferably 160°C or lower. The curing time is, for example, 1 minute or longer, preferably 1 hour or longer, and more preferably 6 hours or longer. The curing time is, for example, 7 days or shorter, preferably 3 days or shorter, and more preferably 1 day or shorter.

[0100] The cast polyurethane elastomer is cooled and demolded as required, and is also aged as required.

[0101] The aging conditions are not particularly limited. For example, the aging temperature is, for example, 0°C or higher, preferably 5°C or higher. The aging temperature is, for example, 40°C or lower, preferably 30°C or lower. The aging time is, for example, 1 hour or longer, preferably 2 hours or longer. The aging time is, for example, 5 days or shorter, preferably 3 days or shorter.

[0102] (3) Effects The cured resin and cast polyurethane elastomer are obtained using the polyurethane resin composition, and therefore have excellent mechanical properties, productivity, and appearance (molding stability and transparency).

[0103] For example, the total light transmittance of the cured resin is, for example, 80% or more, preferably 85% or more, and more preferably 90% or more. The total light transmittance of the cured resin is, for example, 100% or less. The total light transmittance is measured in accordance with JIS K 7375 (2008).

[0104] Therefore, the above-mentioned cured resin and cast polyurethane elastomer are suitable for use in various industrial fields. Applications of the above-mentioned cured resin products and cast polyurethane elastomers include, for example, transparent molded articles, objects, optical components, waterproofing materials, sheets, bands, belts, tubes, blades, speakers, sensors, outsoles, threads, fibers, nonwoven fabrics, cosmetics, shoe supplies, heat insulation materials, sealing materials, tapes, encapsulants, solar power generation components, robot components, android components, wearable components, clothing, sanitary products, cosmetics, furniture components, food packaging components, sporting goods, leisure goods, medical supplies, nursing care products, housing components, acoustic components, lighting components, vibration-damping components, soundproofing components, daily necessities, miscellaneous goods, cushions, bedding, stress absorbing materials, stress relaxation materials, automotive interior materials, automotive exterior materials, railway components, aircraft components, optical components, office automation equipment components, miscellaneous surface protection materials, semiconductor encapsulants, self-repairing materials, health appliances, eyeglass lenses, toys, packing, cable sheaths, wire harnesses, telecommunications cables, automotive wiring, computer wiring, industrial products, shock absorbing materials, and semiconductor components. [Example]

[0105] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited thereto. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values (numeric values defined as "equal to or less than") or lower limit values (numeric values defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0106] 1. Raw materials (A) Polyisocyanate component A-1) STABIO D-370N: Isocyanurate derivative of pentamethylene diisocyanate (PDI), isocyanate group content 24.64% by mass, solid content 100% by mass, manufactured by Mitsui Chemicals

[0107] (B1) Polycarbonate polyol B1-1) Benebiol HS0840B: Trade name, polycarbonate diol, number average molecular weight 800, average number of hydroxyl groups 2, hydroxyl value 140±10 mgKOH / g, viscosity (60°C) 10,000-40,000 mPa·s (catalog value), manufactured by Mitsubishi Chemical B1-2) Benebiol HS0840H: Trade name, polycarbonate diol, number average molecular weight 800, average number of hydroxyl groups 2, hydroxyl value 140±10 mgKOH / g, viscosity (60°C) 5000-15000 mPa·s (catalog value), manufactured by Mitsubishi Chemical

[0108] (B2) Polyether polyol B2-1) Actocol D-400: Trade name, polyoxypropylene diol, number average molecular weight 400, average number of hydroxyl groups 2, manufactured by Mitsui Chemicals B2-2) Actocol T-300: Trade name, polyoxypropylene triol, number average molecular weight 300, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals B2-3) Actocol T-700: Trade name, polyoxypropylene triol, number average molecular weight 700, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals B2-4) Actocol T-1000: Trade name, polyoxypropylene triol, number average molecular weight 1000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals B2-5) Actocol T-3000: Trade name, polyoxypropylene triol, number average molecular weight 3000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals B2-6) Actocol T-5000: Trade name, polyoxypropylene triol, number average molecular weight 5000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals

[0109] (C) Urethane catalyst C-1) K-KAT 6212: Trade name, Zr-based catalyst, manufactured by KING INDUSTRIES C-2) K-KAT XK-661: Product name, Zn-based catalyst, manufactured by KING INDUSTRIES C-3) K-KAT XK628: Trade name, Bi-based catalyst, manufactured by KING INDUSTRIES C-4) Orgatix TC-750: Product name, Ti-based catalyst, manufactured by Matsumoto Fine Chemicals C-5) DBTDL: Dibutyltin dilaurate, Sn-based catalyst, manufactured by Tokyo Chemical Industry Co., Ltd.

[0110] 2. Production of polyurethane resin composition and cured resin Examples 1 to 9 and Comparative Examples 1 to 11 According to the descriptions in Tables 1 to 4, polycarbonate polyol (B1) and polyether polyol (B2) were mixed at 80°C to obtain an active hydrogen group-containing component (B). The active hydrogen group-containing component (B) was degassed under reduced pressure. In Comparative Example 1, polyether polyol (B2) was used alone as the active hydrogen group-containing component (B).

[0111] Next, the active hydrogen group-containing component (B) and the urethanization catalyst (C) were mixed according to the descriptions in Tables 1 to 4 to obtain a mixture.

[0112] Next, the polyisocyanate component (A) heated to 80°C was mixed with the mixture of the active hydrogen group-containing component (B) and the urethanization catalyst (C) according to the descriptions in Tables 1 to 4 to obtain a polyurethane resin composition. The polyurethane resin composition was degassed under reduced pressure.

[0113] The polyurethane resin composition was then poured into a mold (inner dimensions 50 mm x 50 mm x 25 mm) and cured at 80°C for 18 hours. As a result, a cured resin product (cast polyurethane elastomer, 50 mm x 50 mm x 25 mm) was obtained as the cured product of the polyurethane resin composition. In Examples 1 to 9, the total light transmittance (based on JIS K 7375 (2008)) of each cured resin product was 90% or more.

[0114] 3. Evaluation <Active hydrogen group-containing component (B)> (1) Compatibility The compatibility of the active hydrogen group-containing component (B) was evaluated according to the following criteria, and the results are shown in Tables 1 to 4.

[0115] A: The active hydrogen group-containing component (B) was transparent. B: The active hydrogen group-containing component (B) was cloudy. C: The active hydrogen group-containing component (B) separated and could not be used to produce a cured resin.

[0116] (2) Viscosity (80℃) The viscosity (80°C) of the active hydrogen group-containing component was measured under the following conditions. The results are shown in Tables 1 to 4.

[0117] Measurement equipment: TVE-25 viscometer manufactured by Toki Sangyo Measurement temperature: 80℃ Rotor: 1°34' x R24 Measurement range: H Rotation speed: 0.5 to 100 rpm

[0118] <Cured resin> (1) Appearance The appearance of the cured resin product (50 mm x 50 mm x 25 mm) was visually inspected and evaluated according to the following criteria. The results are shown in Tables 1 to 4.

[0119] A: Air bubbles were removed well from the molded product. No sink marks (mold shrinkage) were observed. B: Air bubbles were removed well from the molded product. However, sink marks (mold shrinkage) were observed. C: Air bubbles were not removed from the molded product. Also, sink marks (molding shrinkage) were observed.

[0120] (2) Mechanical properties (hardness) The hardness (HSD hardness) of the cured resin (50 mm×50 mm×25 mm) was measured in accordance with the hardness test of JIS K 7312 (1996). The results are shown in Tables 1 to 4.

[0121]

Table 1

[0122]

Table 2

[0123]

Table 3

[0124]

Table 4

Claims

1. A polyurethane resin composition comprising a polyisocyanate component (A), an active hydrogen group-containing component (B), and a urethanization catalyst (C), The polyisocyanate component (A) contains an isocyanurate derivative of an aliphatic polyisocyanate, The active hydrogen group-containing component (B) contains a polycarbonate polyol (B1) and a polyether polyol (B2), the number average molecular weight of the polyether polyol (B2) is 200 or more and 500 or less, the polyether polyol (B2) has an average number of hydroxyl groups of 3.0 or more, the content of the polyether polyol (B2) is 30% by mass or more and 70% by mass or less based on the total amount of the polycarbonate polyol (B1) and the polyether polyol (B2), The polyurethane resin composition, wherein the urethanization catalyst (C) contains at least one catalyst selected from the group consisting of a Ti-based catalyst, a Zn-based catalyst, a Zr-based catalyst, and a Bi-based catalyst.

2. 2. The polyurethane resin composition according to claim 1, wherein the viscosity (60°C) of the polycarbonate polyol (B1) is 3,000 mPa·s or more and 50,000 mPa·s or less.

3. 2. The polyurethane resin composition according to claim 1, wherein the viscosity (80°C) of the active hydrogen group-containing component (B) is 30 mPa·s or more and 900 mPa·s or less.

4. The polyurethane resin composition according to claim 1 , wherein the aliphatic polyisocyanate contains a chain aliphatic polyisocyanate.

5. The polyurethane resin composition according to claim 1 , wherein the aliphatic polyisocyanate contains pentamethylene diisocyanate.

6. The polyurethane resin composition according to claim 1, wherein the polycarbonate polyol (B1) contains a plant-derived polycarbonate polyol.

7. A cured resin product comprising the cured polyurethane resin composition according to claim 1.

8. A cast polyurethane elastomer comprising the cured resin according to claim 7.

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