Prepolymer composition, polyurethane resin, elastic molded article, and method for producing prepolymer composition

Abstract

The present invention provides a prepolymer composition which contains an isocyanate group-terminated prepolymer. The isocyanate group-terminated prepolymer comprises a reaction product between a polyisocyanate component that contains 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component that contains a first macrodiol and a second macrodiol. The first macrodiol has a hydroxyl value of more than 56.1 mgKOH / g but less than 172 mgKOH / g. The second macrodiol has a hydroxyl value of 374 mgKOH / g to 561 mgKOH / g. The ratio of the second macrodiol relative to the total mole of the first macrodiol and the second macrodiol is 30% by mole to 55% by mole.

Description

Technical Field

[0001] The present invention relates to a prepolymer composition, a polyurethane resin, an elastic molded article, and a method for producing a prepolymer composition.

Background Art

[0002] A polyurethane resin has, for example, a soft segment formed by the reaction of a polyisocyanate and a macro polyol, and a hard segment formed by the reaction of a polyisocyanate and a chain extender.

[0003] More specifically, a polyurethane resin obtained by the following method is known. That is, first, 64.8 parts by mass of 1,4-bis(isocyanatomethyl)cyclohexane, 25 parts by mass of a polyester polyol having a number average molecular weight of 500, and 75 parts by mass of a polyester polyol having a number average molecular weight of 1000 are reacted to obtain an isocyanate group-terminated prepolymer having an isocyanate group content of 10.63% by mass. Next, the isocyanate group-terminated prepolymer and 1,4-butanediol are reacted to obtain a polyurethane resin (see, for example, Patent Document 1 (Synthesis Example 3, Example 3)).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above polyurethane resin has excellent mechanical properties. On the other hand, when the above polyurethane resin is injection molded, internal defects may occur due to shrinkage.

[0006] The present invention includes a prepolymer composition for producing a polyurethane resin having excellent mechanical properties (high hardness) and suppressing internal defects, a polyurethane resin and an elastic molded article obtained from the prepolymer composition, and a method for producing the prepolymer composition.

Means for Solving the Problems

[0007] The present invention [1] is a prepolymer composition containing an isocyanate group-terminated prepolymer, wherein the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a first macrodiol (A) and a second macrodiol (B), the hydroxyl value of the first macrodiol (A) exceeds 56.1 mgKOH / g and is less than 172 mgKOH / g, the hydroxyl value of the second macrodiol (B) is 374 mgKOH / g or more and 561 mgKOH / g or less, and the proportion of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B).

[0008] The present invention [2] includes the prepolymer composition according to the above [1], wherein the proportion of the second macrodiol (B) is 8 mol% or more and 15 mol% or less based on the total moles of the polyisocyanate component, the first macrodiol (A), and the second macrodiol (B).

[0009] The present invention [3] further includes the prepolymer composition according to the above [1] or [2], which contains acetylacetone.

[0010] The present invention [4] includes a reaction product of a prepolymer composition containing an isocyanate group-terminated prepolymer and a chain extension component containing a chain extender (C), wherein the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a first macrodiol (A) and a second macrodiol (B), the hydroxyl value of the first macrodiol (A) exceeds 56.1 mgKOH / g and is less than 172 mgKOH / g, the hydroxyl value of the second macrodiol (B) is 374 mgKOH / g or more and 561 mgKOH / g or less, and the proportion of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B), and contains a polyurethane resin.

[0011] The present invention [5] includes the polyurethane resin according to the above [4], wherein the proportion of the second macrodiol (B) is 5.5 mol% or more and 10.5 mol% or less based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B) and the chain extender (C).

[0012] The present invention [6] includes the polyurethane resin according to the above [4] or [5], wherein the prepolymer composition and / or the chain extension component contains acetylacetone.

[0013] The present invention [7] includes an elastic molded article containing the polyurethane resin according to any one of the above [4] to [6].

[0014] The present invention [8] relates to a method for producing a prepolymer composition containing an isocyanate group-terminated prepolymer, which comprises a step of reacting a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane with a polyol component containing a first macrodiol (A) and a second macrodiol (B), wherein the hydroxyl value of the first macrodiol (A) exceeds 56.1 mgKOH / g and is less than 172 mgKOH / g, the hydroxyl value of the second macrodiol (B) is 374 mgKOH / g or more and 561 mgKOH / g or less, and the proportion of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B).

Advantages of the Invention

[0015] In the present invention, the polyol component contains a first macrodiol (A) and a second macrodiol (B). The hydroxyl value of the first macrodiol (A) and the hydroxyl value of the second macrodiol (B) are within a predetermined range. According to such a prepolymer composition, a polyurethane resin having excellent mechanical properties (high hardness) can be obtained, and internal defects of the polyurethane resin can be suppressed.

[0016] The polyurethane resin and the elastic molded article of the present invention have excellent mechanical properties (high hardness) and can suppress internal defects.

[0017] According to the method for producing the prepolymer composition of the present invention, the above prepolymer composition can be obtained.

Embodiments for Carrying Out the Invention

[0018] The polyurethane resin contains a reaction product of a prepolymer composition (first liquid) and a chain extension component (second liquid). The prepolymer composition (first liquid) and the chain extension component (second liquid) are prepared, for example, as a resin kit and urethanized by being mixed.

[0019] The polyurethane resin preferably consists of the reaction product of a prepolymer composition (first liquid) and a chain extender component (second liquid). That is, the polyurethane resin is preferably a urethane cured product obtained by the reaction and curing of a prepolymer composition and a chain extender component.

[0020] The prepolymer composition (first liquid) contains an isocyanate group-terminated prepolymer as an essential component.

[0021] The isocyanate group-terminated prepolymer includes the reaction product of a polyisocyanate component and a polyol component. Preferably, the isocyanate group-terminated prepolymer consists of the reaction product of a polyisocyanate component and a polyol component.

[0022] The polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane as an essential component. 1,4-Bis(isocyanatomethyl)cyclohexane has, as stereoisomers, cis-1,4-bis(isocyanatomethyl)cyclohexane and trans-1,4-bis(isocyanatomethyl)cyclohexane. Hereinafter, cis-1,4-bis(isocyanatomethyl)cyclohexane may be referred to as the cis 1,4 form. Also, trans-1,4-bis(isocyanatomethyl)cyclohexane may be referred to as the trans 1,4 form. Note that the total amount of the trans 1,4 form and the cis 1,4 form is 100 mol%.

[0023] In 1,4-bis(isocyanatomethyl)cyclohexane, the content ratio of the trans 1,4 form is, for example, 60 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 85 mol% or more. Also, in 1,4-bis(isocyanatomethyl)cyclohexane, the content ratio of the trans 1,4 form is, for example, 100 mol% or less, preferably 99.8 mol% or less, more preferably 99 mol% or less, still more preferably 96 mol% or less, still more preferably 90 mol% or less.

[0024] Also, in 1,4-bis(isocyanatomethyl)cyclohexane, the content ratio of the cis-1,4 isomer is, for example, 0 mol% or more, preferably 0.2 mol% or more, more preferably 1 mol% or more, still more preferably 4 mol% or more, and even more preferably 10 mol% or more. Also, in 1,4-bis(isocyanatomethyl)cyclohexane, the content ratio of the cis-1,4 isomer is, for example, 40 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less, still more preferably 15 mol% or less.

[0025] When the content ratio of the trans-1,4 isomer and the content ratio of the cis-1,4 isomer are within the above ranges, a polyurethane resin excellent in mechanical strength can be obtained.

[0026] Also, 1,4-bis(isocyanatomethyl)cyclohexane may be a modified product as long as it does not inhibit the excellent effects of the present invention. Examples of the modified product include uretdione-modified products, isocyanurate-modified products, iminooxadiazinedione, biuret-modified products, allophanate-modified products, polyol adducts, oxadiazinetrione-modified products, and carbodiimide-modified products.

[0027] The polyisocyanate component can contain, as an optional component, an isocyanate other than 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter referred to as other polyisocyanates) as long as it does not inhibit the excellent effects of the present invention. Examples of the other polyisocyanates include diisocyanates.

[0028] As other polyisocyanates, more specifically, for example, aliphatic polyisocyanates, alicyclic polyisocyanates (excluding 1,4-bis(isocyanatomethyl)cyclohexane), aromatic polyisocyanates, and araliphatic polyisocyanates can be mentioned. Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 1,2-propanediisocyanate, 1,2-butanediisocyanate, 2,3-butanediisocyanate, 1,3-butanediisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanatomethyl caproate. Examples of alicyclic polyisocyanates include 1,3-bis(isocyanatomethyl)cyclohexane (1,3-H6XDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylene bis(cyclohexyl isocyanate) (H 12 MDI). Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, and naphthalene diisocyanate (NDI). Examples of araliphatic polyisocyanates include xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). Further, other polyisocyanates may be the above-mentioned modified products as long as the excellent effects of the present invention are not inhibited. These can be used alone or in combination of two or more.

[0029] The content ratio of other polyisocyanates is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass, based on the total amount of the polyisocyanate component. Further, the content ratio of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, based on the total amount of the polyisocyanate component. That is, the polyisocyanate component particularly preferably consists of 1,4-bis(isocyanatomethyl)cyclohexane.

[0030] The polyol component contains a first macrodiol (A) and a second macrodiol (B). Note that a macrodiol has two hydroxyl groups in the molecule and is a relatively high molecular weight organic compound. Relatively high molecular weight means that the number average molecular weight is 200 or more.

[0031] Examples of the first macrodiol (A) include polyether diol, polyester diol, polycarbonate diol, polyurethane diol, epoxy diol, vegetable oil diol, polyolefin diol, acrylic diol, and vinyl monomer-modified diol. Preferred examples of the first macrodiol (A) include polyether diol, polyester diol, and polycarbonate diol.

[0032] Examples of the polyether diol include polyoxyalkylene diol. Examples of the polyoxyalkylene diol include polyoxyalkylene (C2-3) diol and polytetramethylene ether diol.

[0033] Examples of the polyester diol include condensation polyester diols and ring-opening polyester diols. Examples of the condensation polyester diols include adipate-based polyester diols (e.g., polybutylene adipate) and phthalate-based polyester diols. Examples of the ring-opening polyester diols include lactone-based polyester diols, and more specifically, polycaprolactone diol.

[0034] Examples of the polycarbonate diol include ring-opening polymers of ethylene carbonate using a dihydric alcohol described below as an initiator.

[0035] These first macrodiols (A) can be used alone or in combination of two or more. From the viewpoint of improving mechanical properties and suppressing internal defects, the first macrodiol (A) is preferably a polyether diol, and more preferably polytetramethylene ether diol.

[0036] Examples of the second macrodiol (B) include the above-described polyether diol, the above-described polyester diol, the above-described polycarbonate diol, the above-described polyurethane diol, the above-described epoxy diol, the above-described vegetable oil diol, the above-described polyolefin diol, the above-described acrylic diol, and the above-described vinyl monomer-modified diol.

[0037] These second macrodiols (B) can be used alone or in combination of two or more. From the viewpoint of improving mechanical properties and suppressing internal defects, the second macrodiol (B) is preferably a polyether diol, and more preferably polytetramethylene ether diol. Further, from the viewpoint of compatibility, the second macrodiol (B) is preferably a diol of the same type as the first macrodiol (A).

[0038] In the polyol component, the first macrodiol (A) and the second macrodiol (B) are distinguished from each other by the hydroxyl value. That is, the hydroxyl value of the first macrodiol (A) is smaller than that of the second macrodiol (B).

[0039] More specifically, from the perspective of mechanical properties, the hydroxyl value of the first macrodiol (A) exceeds 56.1 mgKOH / g, preferably 60 mgKOH / g or more, more preferably 75 mgKOH / g or more, and even more preferably 85 mgKOH / g or more. Also, from the perspective of mechanical properties, the hydroxyl value of the first macrodiol (A) is, for example, less than 172 mgKOH / g, preferably 160 mgKOH / g or less, more preferably 150 mgKOH / g or less, and even more preferably 140 mgKOH / g or less.

[0040] Also, from the perspective of suppressing internal defects, the hydroxyl value of the second macrodiol (B) is 374 mgKOH / g or more, preferably 400 mgKOH / g or more, more preferably 416 mgKOH / g or more, and even more preferably 430 mgKOH / g or more. Also, from the perspective of mechanical properties, the hydroxyl value of the second macrodiol (B) is 561 mgKOH / g or less, preferably 510 mgKOH / g or less, more preferably 488 mgKOH / g or less, and even more preferably 468 mgKOH / g or less.

[0041] Also, the difference between the hydroxyl value of the first macrodiol (A) and the hydroxyl value of the second macrodiol (B) is, for example, 202 mgKOH / g or more, preferably 250 mgKOH / g or more, and more preferably 300 mgKOH / g or more. Also, the difference between the hydroxyl value of the first macrodiol (A) and the hydroxyl value of the second macrodiol (B) is, for example, 504.9 mgKOH / g or less, preferably 450 mgKOH / g or less, and more preferably 400 mgKOH / g or less.

[0042] Incidentally, the hydroxyl value can be measured by a known method for measuring the hydroxyl value or the like. Examples of the method for measuring the hydroxyl value include the acetylation method and the phthalation method. Further, the hydroxyl value can also be calculated from the raw material ratio of the first macrodiol (A) and the second macrodiol (B).

[0043] Further, the hydroxyl value can also be calculated, for example, by the following formula (1). Hydroxyl value = 56100 × average number of hydroxyl groups / number average molecular weight (1)

[0044] In the above formula (1), the number average molecular weight of the first macrodiol (A) and the number average molecular weight of the second macrodiol (B) are measured as the molecular weight in terms of standard polystyrene by a known gel permeation chromatogram (GPC) (the same applies hereinafter).

[0045] Further, in the above formula (1), the average number of hydroxyl groups of the first macrodiol (A) is 2. Also, the average number of hydroxyl groups of the second macrodiol (B) is 2.

[0046] Therefore, the first macrodiol (A) and the second macrodiol (B) can also be distinguished by the number average molecular weight. That is, the number average molecular weight of the first macrodiol (A) is larger than the number average molecular weight of the second macrodiol (B).

[0047] More specifically, the number average molecular weight of the first macrodiol (A) exceeds, for example, 650, preferably 700 or more, more preferably 750 or more, still more preferably 800 or more. Also, the number average molecular weight of the first macrodiol (A) is less than, for example, 2000, preferably 1870 or less, more preferably 1500 or less, still more preferably 1300 or less.

[0048] Further, the number average molecular weight of the second macrodiol (B) is 200 or more, preferably 220 or more, more preferably 230 or more, still more preferably 240 or more. Also, the number average molecular weight of the second macrodiol (B) is 300 or less, preferably 280 or less, more preferably 270 or less, still more preferably 260 or less.

[0049] By using such first macrodiol (A) and second macrodiol (B) in combination, the shrinkage of the polyurethane resin is suppressed and the generation of internal defects is suppressed.

[0050] In the polyol component, the combined ratio of the first macrodiol (A) and the second macrodiol (B) is adjusted from the viewpoint of achieving both mechanical properties and suppression of internal defects.

[0051] More specifically, from the viewpoint of mechanical properties, the first macrodiol (A) is 45 mol% or more, preferably 50 mol% or more, more preferably 55 mol% or more, still more preferably 60 mol% or more, based on the total moles of the first macrodiol (A) and the second macrodiol (B). Also, from the viewpoint of suppressing internal defects, the first macrodiol (A) is 70 mol% or less, preferably 68 mol% or less, more preferably 66 mol% or less.

[0052] Also, from the viewpoint of suppressing internal defects, the second macrodiol (B) is 30 mol% or more, preferably 32 mol% or more, more preferably 34 mol% or more, based on the total moles of the first macrodiol (A) and the second macrodiol (B). Also, from the viewpoint of mechanical properties, the second macrodiol (B) is 55 mol% or less, preferably 50 mol% or less, more preferably 45 mol% or less, still more preferably 40 mol% or less.

[0053] The polyol component can contain a macro polyol having an average hydroxyl number of 3 or more as long as it does not inhibit the excellent effects of the present invention. Preferably, the polyol component does not contain a macro polyol having an average hydroxyl number of 3 or more. Further, the polyol component can contain a low molecular weight polyol described below as long as it does not inhibit the excellent effects of the present invention. Preferably, the polyol component does not contain the low molecular weight polyol described below. The total amount of the content ratio of the above-mentioned first macro polyol (A) and the content ratio of the above-mentioned second macro polyol (B) with respect to the total amount of the polyol component is, for example, 90% by mass or more, preferably 95% by mass or more, and particularly preferably 100% by mass. That is, the polyol component particularly preferably consists of the above-mentioned first macro polyol (A) and the above-mentioned second macro polyol (B).

[0054] The prepolymer composition is, for example, a reaction product solution of the above-mentioned polyisocyanate component and the above-mentioned polyol component.

[0055] More specifically, the prepolymer composition is produced by the following method for producing a prepolymer composition. That is, for example, the above-mentioned polyisocyanate component and the above-mentioned polyol component are reacted at a predetermined ratio to prepare a reaction product solution containing an isocyanate group-terminated prepolymer (prepolymer synthesis step).

[0056] In the prepolymer synthesis step, the equivalent ratio R(NCO / OH) of the isocyanate group in the polyisocyanate component to the hydroxyl group in the polyol component is, for example, more than 1.0, preferably 1.5 or more, more preferably 2.0 or more, and still more preferably 2.5 or more. Also, the equivalent ratio R(NCO / OH) of the isocyanate group in the polyisocyanate component to the hydroxyl group in the polyol component is, for example, 20 or less, preferably 10 or less, and more preferably 5 or less.

[0057] From the perspective of improving mechanical properties and suppressing internal defects, the proportion of the polyisocyanate component is, for example, 60 mol% or more, preferably 70 mol% or more, more preferably 72 mol% or more, still more preferably 73 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), and the second macrodiol (B). Also, the proportion of the polyisocyanate component is, for example, 95 mol% or less, preferably 90 mol% or less, more preferably 80 mol% or less, still more preferably 74 mol% or less.

[0058] Also, from the perspective of improving mechanical properties and suppressing internal defects, the proportion of the first macrodiol (A) is, for example, 2 mol% or more, preferably 10 mol% or more, more preferably 14 mol% or more, still more preferably 15 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), and the second macrodiol (B). Also, the proportion of the first macropolyol (A) is, for example, 25 mol% or less, preferably 20 mol% or less, more preferably 18 mol% or less, still more preferably 17 mol% or less.

[0059] Also, from the perspective of improving mechanical properties and suppressing internal defects, the proportion of the second macrodiol (B) is, for example, 5 mol% or more, preferably 7 mol% or more, more preferably 8 mol% or more, still more preferably 9 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), and the second macrodiol (B). Also, the proportion of the second macrodiol (B) is, for example, 20 mol% or less, preferably 15 mol% or less, more preferably 13 mol% or less, still more preferably 10 mol% or less.

[0060] In the prepolymer synthesis step, examples of the reaction method include bulk polymerization and solution polymerization. In bulk polymerization, for example, the polyisocyanate component and the polyol component are reacted under a nitrogen stream. The reaction temperature is, for example, 50°C or higher. Also, the reaction temperature is, for example, 250°C or lower, preferably 200°C or lower. Also, the reaction time is, for example, 0.5 hours or longer, preferably 1 hour or longer. Also, the reaction time is, for example, 15 hours or shorter. In solution polymerization, the polyisocyanate component and the polyol component are reacted in the presence of a known organic solvent. The reaction temperature is, for example, 50°C or higher. Also, the reaction temperature is, for example, 120°C or lower, preferably 100°C or lower. Also, the reaction time is, for example, 0.5 hours or longer, preferably 1 hour or longer. Also, the reaction time is, for example, 15 hours or shorter.

[0061] Thereby, a reaction product solution containing an isocyanate group-terminated prepolymer is obtained. The reaction product solution is a prepolymer composition.

[0062] Also, in the prepolymer synthesis step, if necessary, the reaction product solution can be purified to adjust the isocyanate group concentration of the prepolymer composition. Examples of the purification method include distillation and extraction.

[0063] Also, in the prepolymer synthesis step, if necessary, an isocyanate monomer can be added to the reaction product solution to adjust the isocyanate group concentration of the prepolymer composition.

[0064] That is, in addition to the isocyanate group-terminated prepolymer, the prepolymer composition can contain an isocyanate monomer as an optional component. Examples of the isocyanate monomer include the above-mentioned 1,4-bis(isocyanatomethyl)cyclohexane and the above-mentioned other polyisocyanates (isocyanates excluding 1,4-bis(isocyanatomethyl)cyclohexane). These can be used alone or in combination of two or more.

[0065] Incidentally, the isocyanate monomer may be intentionally added to the prepolymer composition. Also, the isocyanate monomer may be contained in the prepolymer composition as an unavoidable impurity (unreacted monomer). In the prepolymer composition, the content ratio of the isocyanate monomer is appropriately set according to the purpose and application.

[0066] The isocyanate group concentration of the prepolymer composition is, for example, 3.0% by mass or more, preferably 5.0% by mass or more. Also, the isocyanate group concentration of the prepolymer composition is, for example, 20.0% by mass or less, preferably 15.0% by mass or less, more preferably 12.0% by mass or less. Incidentally, the isocyanate group concentration can be determined by a known measurement method. Examples of the measurement method include titration with di-n-butylamine and FT-IR analysis (the same applies hereinafter).

[0067] In such a prepolymer composition, the polyol component includes a first macrodiol (A) and a second macrodiol (B). And the hydroxyl value of the first macrodiol (A) and the hydroxyl value of the second macrodiol (B) are within a predetermined range. According to such a prepolymer composition, a polyurethane resin having excellent mechanical properties (high hardness) can be obtained, and internal defects of the polyurethane resin can be suppressed. Furthermore, according to the above prepolymer composition, the exothermic property of the polyurethane resin can be reduced.

[0068] As described above, the polyurethane resin is composed of a reaction product of a prepolymer composition (first liquid) and a chain extender component (second liquid).

[0069] The chain extender component (second liquid) contains, for example, a chain extender (C) (chain extension compound).

[0070] The chain extender (C) is a curing agent for the prepolymer composition. Examples of the chain extender (C) include low molecular weight polyols and low molecular weight polyamines. Preferably, the chain extender (C) is a low molecular weight polyol. By using a low molecular weight polyol, a polyurethane resin having excellent mechanical strength can be obtained.

[0071] Examples of the low molecular weight polyol include the above-mentioned low molecular weight polyols. More specifically, examples of the low molecular weight polyol include, for example, the above-mentioned dihydric alcohol, the above-mentioned trihydric alcohol, and the above-mentioned tetravalent or higher alcohol. These can be used alone or in combination of two or more.

[0072] Examples of the low molecular weight polyol include dihydric alcohols, trihydric alcohols, and tetravalent or higher alcohols. Examples of the dihydric alcohol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of the trihydric alcohol include glycerin and trimethylolpropane. Examples of the tetravalent or higher alcohol include pentaerythritol and diglycerin. In addition, examples of the low molecular weight polyol also include polymers obtained by addition polymerization of alkylene (C2-3) oxide to di- to tetravalent alcohols so that the number average molecular weight is 400 or less. These can be used alone or in combination of two or more.

[0073] Preferably, the low molecular weight polyol includes dihydric alcohol and trihydric alcohol, more preferably dihydric alcohol, and even more preferably 1,4-butanediol. That is, the low molecular weight polyol preferably contains 1,4-butanediol and more preferably consists of 1,4-butanediol. Thereby, a polyurethane resin having excellent mechanical strength can be obtained.

[0074] The polyurethane resin is produced, for example, by the following method. That is, for example, the above prepolymer composition and the above chain extender component are reacted to chain-extend the isocyanate group-terminated prepolymer (chain extension step).

[0075] In the chain extension step, the equivalent ratio R(NCO / OH) of the isocyanate groups in the prepolymer composition to the hydroxyl groups in the chain extender component (chain extender (C)) is, for example, 0.90 or more, preferably 1.00 or more. Also, the equivalent ratio R(NCO / OH) of the isocyanate groups in the prepolymer composition to the hydroxyl groups in the chain extender component (chain extender (C)) is, for example, 1.33 or less, preferably 1.25 or less.

[0076] From the viewpoint of improving mechanical properties and suppressing internal defects, the proportion of the polyisocyanate component is, for example, 40.0 mol% or more, preferably 47.0 mol% or more, more preferably 49.0 mol% or more, still more preferably 50.0 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B), and the chain extender (C). Also, the proportion of the polyisocyanate component is, for example, 60.0 mol% or less, preferably 55.0 mol% or less, more preferably 52.0 mol% or less, still more preferably 51.0 mol% or less.

[0077] Also, from the viewpoint of improving mechanical properties and suppressing internal defects, the proportion of the first macrodiol (A) is, for example, 6.0 mol% or more, preferably 8.0 mol% or more, more preferably 10.0 mol% or more, still more preferably 11.0 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B), and the chain extender (C). Also, the proportion of the first macropolyol (A) is, for example, 20.0 mol% or less, preferably 18.0 mol% or less, more preferably 15.0 mol% or less, still more preferably 13.0 mol% or less.

[0078] Also, from the perspective of improving mechanical properties and suppressing internal defects, the proportion of the second macrodiol (B) is, for example, 2.0 mol% or more, preferably 4.0 mol% or more, more preferably 5.5 mol% or more, still more preferably 6.0 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B), and the chain extender (C). Also, the proportion of the second macrodiol (B) is, for example, 15.0 mol% or less, preferably 12.0 mol% or less, more preferably 10.5 mol% or less, still more preferably 9.0 mol% or less.

[0079] Also, from the perspective of improving mechanical properties and suppressing internal defects, the proportion of the chain extender (C) is, for example, 20.0 mol% or more, preferably 23.0 mol% or more, more preferably 25.0 mol% or more, still more preferably 28.0 mol% or more, based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B), and the chain extender (C). Also, the proportion of the chain extender (C) is, for example, 50.0 mol% or less, preferably 45.0 mol% or less, more preferably 40.0 mol% or less, still more preferably 35.0 mol% or less.

[0080] In the chain extension step, examples of the reaction method include the above-mentioned bulk polymerization and solution polymerization. In bulk polymerization, the reaction temperature is, for example, 50°C or higher, preferably 100°C or higher. Also, the reaction temperature is, for example, 250°C or lower, preferably 200°C or lower, more preferably 180°C or lower, still more preferably 150°C or lower. Also, the reaction time is, for example, 0.5 hours or more, preferably 1 hour or more. Also, the reaction time is, for example, 24 hours or less, preferably 20 hours or less, more preferably 18 hours or less. In solution polymerization, the reaction temperature is, for example, 50°C or higher. Also, the reaction temperature is, for example, 120°C or lower, preferably 150°C or lower. Also, the reaction time is, for example, 0.5 hours or more, preferably 1 hour or more. Also, the reaction time is, for example, 24 hours or less.

[0081] Thereby, a polyurethane resin containing a reaction product of a prepolymer composition and a chain extender is obtained. Preferably, the mixture of the prepolymer composition and the chain extender is defoamed as necessary, cured in a preheated mold, and demolded. Thereby, a polyurethane resin molded into a desired shape is obtained.

[0082] Further, the prepolymer composition and the chain extender can contain additives as optional components. Examples of the additives include urethanization catalysts (e.g., organometallic catalysts), catalyst activity regulators, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, antiblocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust preventives, and bluing agents. The addition amount and addition timing of the additives are appropriately set according to the purpose and application.

[0083] From the viewpoint of adjusting the urethanization reaction rate in the chain extension step and suppressing internal defects of the polyurethane resin, the prepolymer composition and / or the chain extender preferably contain a catalyst activity regulator.

[0084] Examples of the catalyst activity regulator include acetylacetone and ethyl acetoacetate. These can be used alone or in combination of two or more. Preferably, acetylacetone is mentioned as the catalyst activity regulator. In other words, the prepolymer composition and / or the chain extender preferably contain acetylacetone. More preferably, the prepolymer composition contains a catalyst activity regulator. The content ratio of the catalyst activity regulator is appropriately set according to, for example, the urethanization reaction conditions and the blending amount of the urethanization catalyst (e.g., organometallic catalyst).

[0085] The polyurethane resin may be heat-treated as necessary. The heat treatment temperature is, for example, 50°C or higher, preferably 80°C or higher. Also, the heat treatment temperature is, for example, 200°C or lower, preferably 150°C or lower. Also, the heat treatment time is, for example, 30 minutes or longer, preferably 1 hour or longer. Also, the heat treatment time is, for example, 30 hours or shorter, preferably 20 hours or shorter.

[0086] Also, the polyurethane resin may be aged. The aging temperature is, for example, 10°C or higher, preferably 20°C or higher. Also, the aging temperature is, for example, 50°C or lower, preferably 40°C or lower. Also, the aging time is, for example, 1 hour or longer, preferably 10 hours or longer. Also, the aging time is, for example, 50 days or shorter, preferably 30 days or shorter.

[0087] The polyurethane resin can contain known additives as required. That is, the polyurethane resin may be a polyurethane resin composition. Examples of the additives include urethanization catalysts, catalyst activity regulators, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, anti-blocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust preventives, and bluing agents. The addition amount and addition timing of the additives are appropriately set according to the purpose and application.

[0088] And the above-mentioned polyurethane resin has excellent mechanical properties (high hardness) and can suppress internal defects.

[0089] That is, in the above-mentioned polyurethane resin, the polyol component contains a first macrodiol (A) and a second macrodiol (B). And the hydroxyl value of the first macrodiol (A) and the hydroxyl value of the second macrodiol (B) are within a predetermined range. According to such a prepolymer composition, a polyurethane resin having excellent mechanical properties (high hardness) can be obtained, and internal defects of the polyurethane resin can also be suppressed.

[0090] Therefore, the above-mentioned polyurethane resin has excellent mechanical properties (high hardness) and can suppress internal defects. Furthermore, the above-mentioned polyurethane resin has excellent low heat generation properties.

[0091] As a result, the above polyurethane resin and prepolymer composition are suitably used in various industrial fields that require mechanical properties (high hardness) and suppression of internal defects. Such industrial fields include, for example, elastic molded articles, paints, coating agents, and adhesives. Preferably, elastic molded articles are included.

[0092] Examples of elastic molded articles include polyurethane elastomers. Examples of polyurethane elastomers include TPU (thermoplastic polyurethane resin) and TSU (thermosetting polyurethane resin). Preferably, as the elastic molded article, TSU (thermosetting polyurethane resin) is included.

[0093] Elastic molded articles can be obtained by molding a polyurethane resin using known molding methods. Examples of molding methods include casting molding, hot compression molding, injection molding, extrusion molding, and spinning molding. Also, examples of the shape after molding include plate-like, fibrous, strand-like, film-like, sheet-like, pipe-like, bottle-like, hollow-like, box-like, and button-like.

[0094] Elastic molded articles are preferably obtained by casting molding. Therefore, elastic molded articles are preferably cast polyurethane elastomers. A cast polyurethane elastomer is a molded article (cast molded article) obtained by casting molding, an article having a predetermined shape according to the purpose and use, and is distinguished from a coating agent applied to an object to be coated.

[0095] Since such an elastic molded article contains the above polyurethane resin, it has excellent mechanical strength and can suppress the entrapment of air bubbles. Therefore, the elastic molded article is suitably used in various applications. Examples of the applications of the elastic molded article include, for example, transparent rigid plastics, waterproof materials, potting agents, inks, binders, films, sheets, bands, belts, shoe press belts, tubes, blades, speakers, sensors, outsoles, threads, fibers, non-woven fabrics, cosmetics, shoe supplies, heat insulating materials, sealing materials, tape materials, sealing materials, solar power generation members, robot members, android members, wearable members, clothing supplies, sanitary supplies, cosmetic supplies, furniture supplies, food packaging members, sports supplies, leisure supplies, medical supplies, nursing care supplies, housing members, acoustic members, lighting members, vibration-proof members, sound-proof members, daily necessities, miscellaneous goods, cushions, bedding, stress absorbing materials, stress relieving materials, automotive interior materials, automotive exterior materials, railway members, aircraft members, optical members, members for OA equipment, miscellaneous goods surface protection members, semiconductor encapsulants, self-healing materials, health appliances, spectacle lenses, toys, packings, cable sheaths, wire harnesses, telecommunication cables, automotive wiring, computer wiring, industrial supplies, impact absorbing materials, semiconductor supplies, and bridge bearings.

Examples

[0096] 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 based on mass unless otherwise specified. In addition, the specific numerical values such as the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "below" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0097] 1. Raw materials <Polyisocyanate component> Production Example 1 1,4-Bis(isocyanatomethyl)cyclohexane Based on the description of Production Example 3 in International Publication WO2019 / 069802, 1,4-bis(isocyanatomethyl)cyclohexane (1,4-H6XDI) was obtained. As a result of measuring the purity of 1,4-H6XDI by gas chromatography, it was 99.9%. Also, the hue by APHA measurement was 5. Also, 13 The ratio of the trans form and the cis form measured by 13C-NMR measurement was 86 mol% of the trans form and 14 mol% of the cis form.

[0098] <Polyol component> PTMEG1000: Polytetramethylene ether glycol, number average molecular weight (Mn) 1000 PTMEG650: Polytetramethylene ether glycol, number average molecular weight (Mn) 650 PTMEG500: Polytetramethylene ether glycol, number average molecular weight (Mn) 500 PTMEG300: Polytetramethylene ether glycol, number average molecular weight (Mn) 300 PTMEG250: Polytetramethylene ether glycol, number average molecular weight (Mn) 250 PBA1000: Condensation type polyester diol (polybutylene adipate), number average molecular weight (Mn) 1000 PBA500: Condensation type polyester diol (polybutylene adipate), number average molecular weight (Mn) 500 PBA250: Condensation type polyester diol (polybutylene adipate), number average molecular weight (Mn) 250 PCL1000: Polycaprolactone diol, number average molecular weight (Mn) 1000 PCL250: Polycaprolactone diol, number average molecular weight (Mn) 250 PC1000: Polycarbonate diol, number average molecular weight (Mn) 1000

[0099] <Chain extender> 1,4-BD: 1,4-Butanediol

[0100] <Urethanization catalyst> DBTDL: Dibutyltin dilaurate, an organotin catalyst

[0101] 2. Prepolymer Composition and Polyurethane Resin Examples 1 - 9 and Comparative Examples 1 - 8 (1) Prepolymer Synthesis Step The polyisocyanate component and the polyol component were reacted under a nitrogen atmosphere according to the formulations and conditions described in Tables 1 - 4. In Tables 1 - 4, the equivalent ratio R in the prepolymer synthesis step indicates the equivalent ratio R(NCO / OH) of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the polyol component.

[0102] (2) Chain Extension Step According to the formulations described in Tables 1 - 4, the prepolymer composition and the chain extension component were prepared and heated to 60°C. Then, in the presence of the urethanization catalyst described in Tables 1 - 4, the prepolymer composition and the chain extension component were mixed for 60 seconds and degassed under reduced pressure for 60 seconds at room temperature. Next, the mixture of the main agent and the curing agent was injected into a preheated mold, and the isocyanate group - terminated prepolymer and the chain extender were reacted (cured) based on the reaction conditions in Tables 1 - 4, and then demolded. Thereby, a polyurethane resin (cast polyurethane elastomer) was obtained.

[0103] In the production of the polyurethane resin for evaluating internal defects, the preheating temperature of the mold was set to 60°C, and the thickness of the molded product was set to 5 cm. In the production of the polyurethane resin for evaluating other physical properties (hardness and low heat generation), the preheating temperature of the mold was set to 110°C.

[0104] Also, in Example 9, acetylacetone was added to the prepolymer composition before mixing the prepolymer composition and the chain extension component.

[0105] 3. Physical Property Measurement (1) Isocyanate Group Concentration The isocyanate group concentration was measured in accordance with the n - dibutylamine method of JIS K 1556 (2006).

[0106] 4. Evaluation (1) Internal Defects The inside of a molded body having a 5 cm cubic shape was observed by X-rays using a Rigaku CT Lab GX130 to confirm the presence and size of internal defects.

[0107] The conditions for X-ray observation are as follows. Tube voltage: 130 kV, tube current: 300 μA, FOV: 72 mm, imaging mode: High Resolution, imaging time: 14 min, focal point: L

[0108] The evaluation criteria are as follows. ○: No internal defects were observed. △: Internal defects with a diameter exceeding 0 mm and less than 1.0 mm were observed. ×: Internal defects with a diameter of 1.0 mm or more were observed.

[0109] (2) Mechanical Properties (Hardness) The Shore D hardness of the polyurethane resin was measured in accordance with JIS K 7312 (1996).

[0110] (3) Low Heat Generation (tanδ) As an index of low heat generation, the loss coefficient (tanδ) of the polyurethane resin was calculated. More specifically, the dynamic viscoelastic spectrum of the polyurethane resin was measured using a dynamic viscoelastic measuring device (manufactured by IT Measurement & Control Co., Ltd., model: DVA-220) under the conditions of a measurement start temperature of -100°C, a heating rate of 5°C / min, a tensile mode, a gauge length of 20 mm, a static / dynamic stress ratio of 1.8, and a measurement frequency of 10 Hz. Then, the loss coefficient (tanδ) at 60°C was calculated.

[0111] [Table 1]

[0112] [Table 2]

[0113] [Table 3]

[0114] [Table 4]

[0115] Note that the above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be construed in a limiting sense. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the following claims.

Industrial Applicability

[0116] The prepolymer composition, polyurethane resin, elastic molded article, and method for producing the prepolymer composition of the present invention are suitable for use, for example, in transparent rigid plastics, waterproof materials, potting agents, inks, binders, films, sheets, bands, belts, shoe press belts, tubes, blades, speakers, sensors, outsoles, threads, fibers, non-woven fabrics, cosmetics, shoe products, heat insulating materials, sealing materials, tape materials, sealing materials, solar power generation members, robot members, android members, wearable members, clothing products, sanitary products, cosmetic products, furniture products, food packaging members, sports products, leisure products, medical products, nursing care products, housing members, acoustic members, lighting members, vibration-proof members, sound-proof members, daily necessities, sundries, cushions, bedding, stress absorbing materials, stress relaxing materials, automobile interior materials, automobile exterior materials, railway members, aircraft members, optical members, members for OA equipment, surface protection members for sundries, semiconductor encapsulants, self-healing materials, health appliances, spectacle lenses, toys, packings, cable sheaths, wire harnesses, telecommunication cables, automobile wiring, computer wiring, industrial products, impact absorbing materials, semiconductor products, and bridge bearings.

Claims

1. A prepolymer composition containing an isocyanate group-terminated prepolymer, wherein the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a first macrodiol (A) and a second macrodiol (B), the hydroxyl value of the first macrodiol (A) exceeds 56.1 mg KOH / g and is less than 172 mg KOH / g, the hydroxyl value of the second macrodiol (B) is 374 mg KOH / g or more and 561 mg KOH / g or less, and the proportion of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B), a prepolymer composition.

2. The prepolymer composition according to claim 1, wherein the proportion of the second macrodiol (B) is 8 mol% or more and 15 mol% or less based on the total moles of the polyisocyanate component, the first macrodiol (A) and the second macrodiol (B).

3. Furthermore, the prepolymer composition according to claim 1, which contains acetylacetone.

4. A reaction product of a prepolymer composition containing an isocyanate group-terminated prepolymer and a chain extension component containing a chain extender (C), wherein the isocyanate group-terminated prepolymer contains a reaction product of a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane and a polyol component containing a first macrodiol (A) and a second macrodiol (B), the hydroxyl value of the first macrodiol (A) exceeds 56.1 mg KOH / g and is less than 172 mg KOH / g, the hydroxyl value of the second macrodiol (B) is 374 mg KOH / g or more and 561 mg KOH / g or less, and the proportion of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B), a polyurethane resin.

5. The polyurethane resin according to claim 4, wherein the proportion of the second macrodiol (B) is 5.5 mol% or more and 10.5 mol% or less based on the total moles of the polyisocyanate component, the first macrodiol (A), the second macrodiol (B) and the chain extender (C).

6. The polyurethane resin according to claim 4, wherein the prepolymer composition and / or the chain extension component contains acetylacetone.

7. An elastic molded article comprising the polyurethane resin according to claim 4.

8. A method for producing a prepolymer composition containing an isocyanate group-terminated prepolymer, comprising: a step of reacting a polyisocyanate component containing 1,4-bis(isocyanatomethyl)cyclohexane with a polyol component containing a first macrodiol (A) and a second macrodiol (B), wherein the hydroxyl value of the first macrodiol (A) exceeds 56.1 mg KOH / g and is less than 172 mg KOH / g, the hydroxyl value of the second macrodiol (B) is 374 mg KOH / g or more and 561 mg KOH / g or less, and the ratio of the second macrodiol (B) is 30 mol% or more and 55 mol% or less based on the total moles of the first macrodiol (A) and the second macrodiol (B).

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