Polycarbonate polyol, polyurethane resin forming composition, potting material, polyurethane resin, and sealed body

Abstract

To provide a polycarbonate polyol which is easily handled at normal temperature and is excellent in heat resistance and low-temperature flexibility.SOLUTION: A polycarbonate polyol comprising a plurality of polyols as monomer units, wherein the polyols constituting the monomer units comprise at least two linear glycols and at least one branched glycol, the average number of carbon atoms of the polyols is 6.5 to 10, the branched glycol comprises 3-methyl-1, 5-pentanediol, and the content of 3-methyl-1, 5-pentanediol in the polyols is 2 to 44 mol%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a polycarbonate polyol, a polyurethane resin-forming composition, a potting material, a polyurethane resin, and an encapsulant. [Background technology]

[0002] Polyurethane resins are generally formed by the reaction of a polyol with a polyisocyanate component. Among polyurethane resins, those using polycarbonate polyol as the polyol are known to have excellent durability, such as heat resistance, and are expected to be used in a wide range of applications, such as synthetic leather, artificial leather, paints, coating materials, adhesives, pressure-sensitive adhesives, and potting materials.

[0003] However, typical polycarbonate polyols (e.g., polycarbonate polyols made primarily from 1,6-hexanediol) have high crystallinity and are solid at room temperature (25°C ± 10-15°C), posing workability challenges. For example, when synthesizing a polyurethane resin by mixing polycarbonate polyol with isocyanate, it is necessary to heat the polycarbonate polyol to about 80°C to liquefy it, or to dissolve the polycarbonate polyol using a large amount of solvent.

[0004] In view of the above circumstances, studies have been conducted to make polycarbonate polyol liquid at room temperature without impairing heat resistance. For example, Patent Document 1 discloses a liquid polycarbonate polyol obtained using 1,5-pentanediol and 1,6-hexanediol as raw materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 02-289616 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polycarbonate polyol of Patent Document 1 tends to have a relatively high glass transition temperature, and there is room for improvement in terms of flexibility in low-temperature environments (hereinafter referred to as "low-temperature flexibility").

[0007] Therefore, one aspect of the present disclosure aims to provide a polycarbonate polyol that is easy to handle at room temperature and has excellent heat resistance and low-temperature flexibility. Another aspect of the present disclosure aims to provide a polyurethane resin-forming composition, a potting material, a polyurethane resin, and an encapsulant obtained from the polycarbonate polyol. [Means for solving the problem]

[0008] In some aspects, the present disclosure provides the following [1] to

[18] .

[0009] [1] A polycarbonate polyol containing multiple types of polyols as monomer units, the polyol constituting the monomer units contains at least two types of linear glycols and at least one type of branched glycol; The polyol has an average carbon number of 6.5 to 10, the branched glycol comprises 3-methyl-1,5-pentanediol; A polycarbonate polyol, wherein the content of 3-methyl-1,5-pentanediol in the polyol is 2 to 44 mol %.

[0010] [2] The polycarbonate polyol according to [1], wherein the polyol comprises a first linear glycol having 7 or less carbon atoms and a second linear glycol having 8 or more carbon atoms.

[0011] [3] The polycarbonate polyol according to [2], wherein the first linear glycol comprises 1,6-hexanediol.

[0012] [4] The polycarbonate polyol according to [2] or [3], wherein the second linear glycol comprises at least one selected from the group consisting of 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0013] [5] The polycarbonate polyol according to any one of [2] to [4], wherein the content of the first linear glycol in the polyol is 1 to 88 mol %.

[0014] [6] The polycarbonate polyol according to any one of [2] to [5], wherein the content of the second linear glycol in the polyol is 10 to 97 mol %.

[0015] [7] The polycarbonate polyol according to any one of [2] to [6], wherein the molar ratio of the content of the first linear glycol to the content of the second linear glycol in the polyol is 0.01 to 8.8.

[0016] [8] The polycarbonate polyol according to any one of [1] to [7], wherein the molar ratio of the content of the linear glycol to the content of the branched glycol in the polyol is 1.2 to 49.

[0017] [9] The polycarbonate polyol according to any one of [1] to [8], wherein the content of glycols having 6 or more carbon atoms in the polyol is 90 mol % or more.

[0018]

[10] The polycarbonate polyol according to any one of [1] to [9], wherein the content of glycols having 6 to 12 carbon atoms in the polyol is 90 mol % or more.

[0019]

[11] The polycarbonate polyol according to any one of [1] to

[10] , which has a hydroxyl value of 30 to 180 mgKOH / g.

[0020]

[12] A polyurethane resin-forming composition comprising the polycarbonate polyol according to any one of [1] to

[11] and a polyisocyanate.

[0021]

[13] The polyurethane resin-forming composition according to

[12] , wherein the polyisocyanate includes a non-aromatic polyisocyanate.

[0022]

[14] The polyurethane resin-forming composition according to

[13] , wherein the non-aromatic polyisocyanate includes an isocyanurate-modified aliphatic polyisocyanate.

[0023]

[15] The polyurethane resin-forming composition according to

[14] , wherein the content of the isocyanurate-modified product is 60 to 100% by mass based on the total mass of the polyisocyanate.

[0024]

[16] A polyurethane resin formed from the polyurethane resin-forming composition according to any one of

[12] to

[15] .

[0025]

[17] A potting material comprising the polyurethane resin-forming composition according to any one of

[12] to

[15] .

[0026]

[18]

[17] A sealing body having a sealing part formed from the potting material according to

[17] . [Effects of the Invention]

[0027] According to one aspect of the present disclosure, there is provided a polycarbonate polyol that is easy to handle at room temperature and has excellent heat resistance and low-temperature flexibility. Also, according to another aspect of the present disclosure, there are provided a polyurethane resin-forming composition, a potting material, a polyurethane resin, and an encapsulant obtained from the polycarbonate polyol. DETAILED DESCRIPTION OF THE INVENTION

[0028] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. Furthermore, unless specifically stated otherwise, the units of the numerical values ​​before and after "to" are the same. In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in a certain stage may be replaced with the upper or lower limit of a numerical range in another stage. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, the upper and lower limits described individually can be combined in any combination.

[0029] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to the following embodiments.

[0030] <Polycarbonate polyol> One embodiment of the present disclosure is a polycarbonate polyol (hereinafter referred to as "polycarbonate polyol A") comprising multiple types of polyols as monomer units, wherein the polyols constituting the monomer units comprise at least two types of linear glycols and at least one type of branched glycol, the polyols have an average carbon number of 6.5 to 10, the branched glycol comprises 3-methyl-1,5-pentanediol, and the content of 3-methyl-1,5-pentanediol in the polyol is 2 to 44 mol%.

[0031] Here, "polycarbonate polyol" is a compound having one or more carbonate groups (-OC(=O)O-) and multiple hydroxyl groups. The compound has a structure in which multiple monomer units consisting of polyol are connected via carbonate groups. Furthermore, a "monomer unit" is the smallest unit constituting a polymer and does not contain a carbonate group. Furthermore, a "glycol" is a compound having a structure in which one hydroxy group substitutes for every two carbon atoms of a chain aliphatic hydrocarbon or a cyclic aliphatic hydrocarbon. Furthermore, the content in a polyol is the content based on the total amount of the polyol.

[0032] Polycarbonate polyol A can maintain a liquid state for a long period of time at room temperature (25°C ± 10 to 15°C). Therefore, polycarbonate polyol A is easy to handle at room temperature. Polycarbonate polyol A is also resistant to weight loss due to heating. That is, polycarbonate polyol A has excellent heat resistance (oxidative degradation resistance). Furthermore, polycarbonate polyol A has a low glass transition temperature (Tg) and excellent low-temperature flexibility. In this specification, "liquid" means that when an object is tilted, even a slight flow of the object can be visually confirmed. Because crystallization of polycarbonate polyols can take time, whether polycarbonate polyol A is liquid at a predetermined temperature is confirmed by first heating polycarbonate polyol A to 100°C or higher and then leaving it to stand at the predetermined temperature for 24 hours.

[0033] The polycarbonate polyol A is, for example, a reaction product (polycondensate) obtained by a transesterification reaction (polycondensation reaction) between the above-mentioned polyol (a polyol containing at least two types of linear glycols and at least one type of branched glycol, having an average carbon number of 6.5 to 10, wherein the branched glycol contains 3-methyl-1,5-pentanediol in a content of 2 to 44 mol%) and a carbonate. The transesterification reaction between a polyol and a carbonate forms a compound containing a polyol residue (a residue obtained by removing n hydroxyl groups from a polyol) and a carbonate group (—OC(═O)O—). When the polyol used as the reaction raw material is a monomer (non-polymer) such as a glycol, the residue obtained by removing n hydroxyl groups from the monomer constitutes a monomer unit. Here, n is determined by the number of hydroxyl groups contained in the polyol. When the polyol is a diol, n is 1 or 2, and when the polyol is a triol, n is an integer of 1 to 3.

[0034] (Polyol) The polyol contains at least two linear glycols and at least one branched glycol. That is, the polycarbonate polyol contains monomer units represented by the formula: -R 1 -[R in the formula 1 represents a linear aliphatic hydrocarbon group.] and two or more types of monomer units represented by the formula: -R 2 -[R in the formula 2 represents a branched aliphatic hydrocarbon group.] and one or more monomer units represented by the following formula:

[0035] The number of types of linear glycol contained in the polyol may be 2 to 4, or 2 to 3, or even 2. The number of carbon atoms in the linear glycol is, for example, 2 to 20, or may be 6 to 12 or 6 to 10. When the polyol contains a linear glycol having 6 or more carbon atoms, the heat resistance of the polycarbonate polyol tends to be further improved. When the polyol contains a linear glycol having 6 to 12 carbon atoms, the heat resistance and low-temperature flexibility of the polycarbonate polyol tend to be further improved. When the polyol contains a linear glycol having 6 to 10 carbon atoms, the low-temperature stability of the polycarbonate polyol tends to be improved, and the polycarbonate polyol tends to remain liquid for a long period of time even in a low-temperature environment (for example, an environment of 5°C or below).

[0036] Examples of linear glycols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, and 1,20-eicosanediol. Among these, a combination of a linear glycol having 7 or less carbon atoms (hereinafter referred to as a "first linear glycol") and a linear glycol having 8 or more carbon atoms (hereinafter referred to as a "second linear glycol") tends to further improve the heat resistance and low-temperature flexibility of the polycarbonate polyol. This tendency is remarkable when a linear glycol having 6 to 7 carbon atoms is used as the first linear glycol and when a linear glycol having 8 to 12 carbon atoms is used as the second linear glycol, and is particularly remarkable when 1,6-hexanediol is used as the first linear glycol and when at least one selected from the group consisting of 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol is used as the second linear glycol. From the above viewpoint, the linear glycol may include at least one combination selected from the group consisting of a combination of 1,6-hexanediol and 1,9-nonanediol, a combination of 1,6-hexanediol and 1,10-decanediol, a combination of 1,6-hexanediol and 1,11-undecanediol, and a combination of 1,6-hexanediol and 1,12-dodecanediol.

[0037] From the viewpoint of further improving the heat resistance of the polycarbonate polyol, at least one selected from the group consisting of 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol may be used as the second linear glycol.

[0038] From the viewpoint of improving the low-temperature flexibility and low-temperature stability of the polycarbonate polyol, at least one selected from the group consisting of 1,9-nonanediol and 1,10-decanediol may be used as the second linear glycol. In particular, when 1,9-nonanediol is used, the above-mentioned effects tend to be more pronounced.

[0039] The content of the first linear glycol in the polyol (i.e., the proportion of monomer units consisting of the first linear glycol to all monomer units consisting of the polyol) may be 1 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 35 mol% or more, 40 mol% or more, or 45 mol% or more from the viewpoint of improving the heat resistance of the polycarbonate polyol, and may be 88 mol% or less, 80 mol% or less, 70 mol% or less, 65 mol% or less, or 60 mol% or less from the viewpoint of improving the handleability of the polycarbonate polyol. From these viewpoints, the content of the first linear glycol in the polyol may be, for example, 1 to 88 mol%, 10 to 80 mol%, 20 to 70 mol%, 30 to 65 mol%, 35 to 60 mol%, 40 to 60 mol%, or 45 to 60 mol%. In this embodiment, from the same viewpoint as above, the content of the linear glycol having 6 to 7 carbon atoms may be within the above range, and the content of 1,6-hexanediol may be within the above range.

[0040] The content of the second linear glycol in the polyol (i.e., the proportion of monomer units consisting of the second linear glycol to all monomer units consisting of the polyol) may be 10 mol% or more, 12 mol% or more, 14 mol% or more, 16 mol% or more, 18 mol% or more, or 20 mol% or more from the viewpoint of improving the heat resistance of the polycarbonate polyol, and may be 97 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 45 mol% or less, 40 mol% or less, 35 mol% or less, or 30 mol% or less from the viewpoint of improving the handleability of the polycarbonate polyol. From these viewpoints, the content of the second linear glycol in the polyol may be, for example, 10 to 97 mol%, 12 to 90 mol%, 14 to 80 mol%, 16 to 70 mol%, 18 to 60 mol%, 20 to 50 mol%, 20 to 45 mol%, 20 to 40 mol%, 20 to 35 mol%, or 20 to 30 mol%. In this embodiment, from the same viewpoints as above, the content of the linear glycol having 8 to 12 carbon atoms may be within the above range, and the total content of 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol may be within the above range.

[0041] The molar ratio of the content of the first linear glycol to the content of the second linear glycol in the polyol (first linear glycol / second linear glycol) may be 0.01 or more, 0.1 or more, 0.5 or more, 1.0 or more, 1.2 or more, or 1.5 or more from the viewpoint of improving the low-temperature flexibility and handleability of the polycarbonate polyol, and may be 8.8 or less, 6.0 or less, 4.0 or less, 3.0 or less, 2.5 or less, or 2.2 or less from the viewpoint of improving the heat resistance and handleability of the polycarbonate polyol. From these viewpoints, the molar ratio may be 0.01 to 8.8, 0.1 to 6.0, 0.5 to 4.0, 1.0 to 3.0, 1.2 to 2.5, or 1.5 to 2.2.

[0042] The number of types of branched glycol contained in the polyol may be 1 to 3, or may be 1 to 2, or may be 1. The number of carbon atoms in the branched glycol is, for example, 3 to 20, or may be 4 to 15, 6 to 12, or 6 to 10. Examples of branched glycols include propylene glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, and 1,12-octadecanediol.

[0043] The branched glycol contains at least 3-methyl-1,5-pentanediol. The content of 3-methyl-1,5-pentanediol in the branched glycol may be 90 mol% or more, 95 mol% or more, or even 100 mol%.

[0044] The content of 3-methyl-1,5-pentanediol in the polyol (i.e., the proportion of monomer units consisting of 3-methyl-1,5-pentanediol in all monomer units consisting of the polyol) is 2 to 44 mol%. The content of 3-methyl-1,5-pentanediol in the polyol may be 3 mol% or more, 5 mol% or more, 6 mol% or more, 8 mol% or more, 10 mol% or more, 12 mol% or more, or 14 mol% or more from the viewpoint of improving the handleability and low-temperature stability of the polycarbonate polyol, and may be 42 mol% or less, 40 mol% or less, 37 mol% or less, 34 mol% or less, 31 mol% or less, or 28 mol% or less from the viewpoint of improving the heat resistance and low-temperature flexibility of the polycarbonate polyol. From these viewpoints, the content of 3-methyl-1,5-pentanediol in the polyol may be, for example, 3 to 42 mol%, 5 to 40 mol%, 6 to 37 mol%, 8 to 34 mol%, 10 to 31 mol%, 12 to 28 mol%, or 14 to 28 mol%.

[0045] The molar ratio of the linear glycol content to the branched glycol content in the polyol (linear glycol / branched glycol) may be 1.2 or more, 1.3 or more, 1.6 or more, 1.7 or more, 1.9 or more, 2.1 or more, 2.5 or more, or 2.8 or more from the viewpoint of improving the heat resistance of the polycarbonate polyol, and may be 49 or less, 24 or less, 16 or less, 12 or less, 9 or less, 7 or less, 6 or less, or 5 or less from the viewpoint of improving the handleability of the polycarbonate polyol. From these viewpoints, the molar ratio may be, for example, 1.2 to 49, 1.3 to 24, 1.6 to 16, 1.7 to 12, 1.9 to 9, 2.1 to 7, 2.5 to 6, or 2.8 to 5. In this embodiment, from the same viewpoint as above, the molar ratio of the content of the linear glycol having 6 to 12 carbon atoms to the content of 3-methyl-1,5-pentanediol may be in the above-mentioned range, and the molar ratio of the content of the linear glycol having 6 to 10 carbon atoms to the content of 3-methyl-1,5-pentanediol may be in the above-mentioned range.

[0046] The molar ratio of the content of the first linear glycol to the content of the branched glycol in the polyol (first linear glycol / branched glycol) may be 0.02 or more, 0.2 or more, 0.5 or more, 0.8 or more, 1 or more, 1.2 or more, or 1.6 or more from the viewpoint of improving the heat resistance of the polycarbonate polyol, and may be 44 or less, 20 or less, 11 or less, 8 or less, 6 or less, 5 or less, or 4 or less from the viewpoint of improving the handleability of the polycarbonate polyol. From these viewpoints, the molar ratio may be, for example, 0.02 to 44, 0.2 to 20, 0.5 to 11, 0.8 to 8, 1 to 6, 1.2 to 5, or 1.6 to 4. In this embodiment, from the same viewpoint as above, the molar ratio of the content of the linear glycol having 6 to 7 carbon atoms to the content of 3-methyl-1,5-pentanediol may be in the above range, and the molar ratio of the content of 1,6-hexanediol to the content of 3-methyl-1,5-pentanediol may be in the above range.

[0047] The molar ratio of the content of the second linear glycol to the content of the branched glycol in the polyol (second linear glycol / branched glycol) may be 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more from the viewpoint of improving the heat resistance and low-temperature flexibility of the polycarbonate polyol, and may be 49 or less, 23 or less, 14 or less, 9 or less, 7 or less, 5 or less, 4 or less, 3 or less, 2 or less, or 1.5 or less from the viewpoint of improving the handleability of the polycarbonate polyol. From these viewpoints, the molar ratio may be, for example, 0.2 to 49, 0.3 to 23, 0.4 to 14, 0.5 to 9, 0.6 to 7, 0.7 to 5, 0.8 to 4, 0.8 to 3, 0.8 to 2, or 0.8 to 1.5. In this embodiment, from the same viewpoint as above, the molar ratio of the content of the linear glycol having 8 to 12 carbon atoms to the content of 3-methyl-1,5-pentanediol may be in the above-mentioned range, and the molar ratio of the total content of 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol to the content of 3-methyl-1,5-pentanediol may be in the above-mentioned range.

[0048] The polyol may contain a polyol having a cyclic structure (e.g., an aromatic polyol or an alicyclic polyol), but the content of the polyol having a cyclic structure in the polyol may be 20 mol% or less from the viewpoint of improving the low-temperature flexibility of the polycarbonate polyol. From the same viewpoint, the content of the aromatic polyol in the polyol may be 20 mol% or less, and the content of the alicyclic polyol may be 20 mol% or less.

[0049] The polyol may contain a polyol other than glycol (a polyol having three or more hydroxyl groups), and from the viewpoint of improving the low-temperature flexibility of the polycarbonate polyol, the glycol content in the polyol may be 90 mol% or more, 95 mol% or more, or 100 mol%. A polycarbonate polyol having a glycol content of 100 mol% is a polycarbonate diol. Furthermore, from the viewpoint of improving the heat resistance of the polycarbonate polyol, the content of glycols having 6 or more carbon atoms in the polyol may be 90 mol% or more, 95 mol% or more, or 100 mol%. Furthermore, from the viewpoint of improving the heat resistance and low-temperature flexibility of the polycarbonate polyol, the content of glycols having 6 to 12 carbon atoms in the polyol may be 90 mol% or more, 95 mol% or more, or 100 mol%.

[0050] The average carbon number of the polyol is 6.5 to 10. From the viewpoint of improving the low-temperature flexibility of the polycarbonate polyol, the average carbon number of the polyol may be 7 or more or 7.5 or more, and from the viewpoint of improving the handleability of the polycarbonate polyol, the average carbon number of the polyol may be 9 or less or 8 or less. From these viewpoints, the average carbon number of the polyol may be 7 to 9 or 7.5 to 8. Here, the average carbon number of the polyol is the molar average carbon number, and is a weighted average value weighted by the amount of substance (mol%) contained in the polyol of each carbon number.

[0051] (carbonate) The carbonate may include one type of carbonate or two or more types of carbonates. The carbonate may be any compound capable of condensing with a polyol to produce a polycarbonate polyol. Examples of the carbonate include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and dipropyl carbonate; alkylene carbonates such as ethylene carbonate and propylene carbonate; and diaryl carbonates such as diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate, and bistetrahydronaphthyl carbonate.

[0052] (Physical Properties) The hydroxyl value of the polycarbonate polyol A is, for example, 30 to 180 mgKOH / g. When the hydroxyl value of the polycarbonate polyol A is 30 mgKOH / g or more, the heat resistance of the polyurethane resin tends to be further improved. When the hydroxyl value of the polycarbonate polyol A is 30 mgKOH / g or more, the fluidity of the polycarbonate polyol at room temperature tends to be better. When the hydroxyl value of the polycarbonate polyol A is 180 mgKOH / g or less, the low-temperature flexibility of the polyurethane resin tends to be further improved. From these viewpoints, the hydroxyl value of the polycarbonate polyol A may be 40 mgKOH / g or more or 50 mgKOH / g or more, or may be 150 mgKOH / g or less or 130 mgKOH / g or less. In this specification, the hydroxyl value means the number of milligrams (mg) of potassium hydroxide equivalent to the hydroxyl groups in 1 g of a sample, and is measured in accordance with JIS K1557-1.

[0053] The molecular weight of the polycarbonate polyol A may be 600 or more, 1000 or more, or 1500 or more, from the viewpoint of reducing the urethane group concentration of the polyurethane resin and improving the low-temperature flexibility of the polyurethane resin. The molecular weight of the polycarbonate polyol A may be 4000 or less, 3500 or less, or 3000 or less, from the viewpoint of improving the heat resistance of the polyurethane resin and the fluidity of the polycarbonate polyol at room temperature. From these viewpoints, the molecular weight of the polycarbonate polyol A may be 600 to 4000, 1000 to 3500, or 1500 to 3000. The molecular weight is a value calculated from the hydroxyl value and number of hydroxyl groups of the polycarbonate polyol A. The number of hydroxyl groups of the polycarbonate polyol is, for example, 2 to 3.

[0054] The polycarbonate polyol A is liquid at room temperature (25°C ± 10 to 15°C). The polycarbonate polyol A may be liquid at 5°C or 0°C.

[0055] The glass transition temperature (Tg) of the polycarbonate polyol A is, for example, −54° C. or lower, and may be −55° C. or lower, −56° C. or lower, −57° C. or lower, or −58° C. or lower. The lower limit of the glass transition temperature (Tg) of the polycarbonate polyol A is, for example, −65° C. That is, the glass transition temperature (Tg) of the polycarbonate polyol A may be, for example, −65 to −54° C. The glass transition temperature can be measured in accordance with JIS K6240.

[0056] (Manufacturing method) A method for producing polycarbonate polyol A includes, for example, a step of polycondensing the above-mentioned polyol and carbonate by transesterification. In this step, for example, in the presence of a catalyst such as tetrabutoxytitanium, a reaction apparatus equipped with a stirrer, thermometer, heater, and distillation column is used. The temperature is gradually increased to 190°C under a nitrogen stream while distilling off ethanol, and the pressure is gradually reduced to 0.5 kPa or less. The reaction is continued at a pressure of 0.5 kPa or less for 4 hours or more to carry out the polycondensation reaction of the polyol and carbonate. The blending ratio of the polyol and carbonate can be adjusted as appropriate from the viewpoints of the hydroxyl value of the polycarbonate polyol and the volatility of the carbonate.

[0057] The polycarbonate polyol A described above is suitable for use as a polyol for forming a polyurethane resin. By using the polycarbonate polyol A, a polyurethane resin excellent in heat resistance and low-temperature properties (low-temperature flexibility) can be easily obtained.

[0058] <Polycarbonate polyol composition> Another embodiment of the present disclosure is a polycarbonate polyol composition comprising the polycarbonate polyol A described above.

[0059] The polycarbonate polyol composition may contain one or more types of polycarbonate polyol A. The polycarbonate polyol composition may be a composition consisting of only the polycarbonate polyol A, or may contain components other than the polycarbonate polyol A.

[0060] The polycarbonate polyol composition may contain by-products and unreacted raw materials (polyol, carbonate, catalyst, etc.) mixed in during the production process of the polycarbonate polyol A. The polycarbonate polyol composition may contain other components described below.

[0061] The content of polycarbonate polyol A in the polycarbonate polyol composition may be 60 to 100 mass %, 70 to 95 mass %, or 80 to 90 mass % based on the total mass of the polycarbonate polyol composition.

[0062] The polycarbonate polyol composition may be a reaction mixture containing polycarbonate polyol A obtained by the above-mentioned method for producing polycarbonate polyol A (a reaction mixture obtained by a transesterification reaction between a polyol containing at least two types of linear glycols and at least one type of branched glycol, the polyol having an average carbon number of 6.5 to 10, the branched glycol containing 3-methyl-1,5-pentanediol, and the 3-methyl-1,5-pentanediol content being 2 to 44 mol %) and a carbonate).

[0063] <Polyurethane Resin-Forming Composition> Another embodiment of the present disclosure is a polyurethane resin-forming composition (hereinafter referred to as "polyurethane resin-forming composition A") containing the above polycarbonate polyol A and a polyisocyanate.

[0064] The polyurethane resin-forming composition A can easily form a polyurethane resin with excellent heat resistance and low-temperature properties (low-temperature flexibility). Because the polyurethane resin has excellent heat resistance, it is less likely to lose weight due to heat and tends to be able to maintain excellent low-temperature properties for a long period of time. Furthermore, the polyurethane resin obtained from the polyurethane resin-forming composition A tends to have good hardness and tends to be able to maintain that hardness for a long period of time.

[0065] The polycarbonate polyol A and the polyisocyanate contained in the polyurethane resin-forming composition A may be one type or a plurality of types. The polyurethane resin-forming composition A may contain the polycarbonate polyol composition described above.

[0066] The polyisocyanate is not particularly limited, and a wide variety of known polyisocyanates can be used. In particular, when a polyisocyanate having no aromatic ring (non-aromatic polyisocyanate) is used, the low-temperature flexibility of the polyurethane resin tends to be further improved.

[0067] Examples of non-aromatic polyisocyanates include aliphatic polyisocyanates and their derivatives. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, 2,2'-dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, decamethylene diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, and 2,4,4-trimethylhexamethyl. Examples of the isocyanate include methylene diisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, 2,5,7-trimethyl-1,8-diisocyanate-5-isocyanate methyl octane, bis(isocyanate ethyl) carbonate, bis(isocyanate ethyl) ether, 1,4-butylene glycol dipropyl ether-α,α'-diisocyanate, lysine diisocyanate methyl ester, 2-isocyanate ethyl-2,6-diisocyanate hexanoate, and 2-isocyanate propyl-2,6-diisocyanate hexanoate. Examples of the derivatives of aliphatic polyisocyanates include isocyanurate-modified products, allophanate-modified products, biuret-modified products, urethane-modified products, urea-modified products, carbodiimide-modified products, uretonimine-modified products, and uretdione-modified products.

[0068] The use of a derivative of an aliphatic polyisocyanate as the non-aromatic polyisocyanate makes it easier to achieve both high heat resistance and flexibility in low-temperature environments. In particular, when an isocyanurate-modified aliphatic polyisocyanate is used, higher heat resistance tends to be obtained, and when an allophanate-modified aliphatic polyisocyanate is used, flexibility in low-temperature environments tends to be further improved.

[0069] The content of the isocyanurate-modified compound may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 50% by mass or more from the viewpoint of obtaining higher heat resistance, and may be 99.99% by mass or less, 99.9% by mass or less, 99% by mass or less, or 95% by mass or less from the viewpoint of obtaining better flexibility in low-temperature environments. From these viewpoints, the content of the isocyanurate-modified compound may be 10 to 100% by mass, 10 to 99.9% by mass, 20 to 99% by mass, 30 to 99% by mass, 30 to 95% by mass, or 50 to 95% by mass. In particular, when the content of the isocyanurate-modified compound is 60 to 100% by mass, excellent heat resistance tends to be obtained. Note that the above content is the content based on the total mass of the polyisocyanate.

[0070] The content of the allophanate-modified polymer may be 0.01% by mass or more, 1% by mass or more, or 5% by mass or more from the viewpoint of superior flexibility in low-temperature environments, and may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 50% by mass or less from the viewpoint of obtaining higher heat resistance. From these viewpoints, the content of the allophanate-modified polymer may be 0.01 to 90% by mass, 1 to 80% by mass, 1 to 70% by mass, 5 to 70% by mass, or 5 to 50% by mass. The above content is based on the total mass of the polyisocyanate.

[0071] The non-aromatic polyisocyanate may not have a urethane group from the viewpoint of achieving superior flexibility in low-temperature environments, and from the same viewpoint, the polyurethane resin-forming composition may not contain a polyurethane polyisocyanate.

[0072] The polyurethane resin-forming composition A may be a one-component composition in which polycarbonate polyol A and polyisocyanate are mixed in one component, or may be a multi-component (e.g., two-component) composition comprising at least a first component containing polycarbonate polyol A (e.g., the polycarbonate polyol composition) and a second component containing polyisocyanate.

[0073] The polycarbonate polyol A and the polyisocyanate may be blended so that the NCO index is 50 to 120. The NCO index refers to the percentage of the number of moles of all isocyanate groups (NCO groups) in the isocyanate group-containing compound relative to the number of moles of all active hydrogen groups in the active hydrogen group-containing compound contained in the composition (NCO groups / active hydrogen groups × 100).

[0074] In the polyurethane resin-forming composition, the content of polycarbonate polyol A may be 50 to 95 mass%, 60 to 95 mass%, 50 to 90 mass%, 60 to 85 mass%, or 70 to 80 mass%. When the content of polycarbonate polyol A is 60 mass% or more, flexibility in low-temperature environments tends to be superior, and when the content of polycarbonate polyol A is 95 mass% or less, heat resistance tends to be superior. In the polyurethane resin-forming composition, the content of polyisocyanate may be 5 to 50 mass%, 5 to 40 mass%, 10 to 50 mass%, 15 to 40 mass%, or 20 to 30 mass%. Here, the contents of the polycarbonate polyol A and polyisocyanate are based on the total mass of the polyurethane resin-forming composition when the polyurethane resin-forming composition is a one-component composition, and when the polyurethane resin-forming composition is a two-component composition, they are based on the total mass of the mixed liquid obtained when the first and second components are mixed so that the NCO index is 50 to 120 (e.g., 100). When the polyurethane resin-forming composition is a two-component composition, the content of polycarbonate polyol A being within the above range means that the content of polycarbonate polyol in the mixed liquid is within the above range when the NCO index is any value between 50 and 120 (e.g., 100). The same applies to the content of polyisocyanate.

[0075] The polyurethane resin-forming composition A may further contain components (other components) other than the polycarbonate polyol A and the polyisocyanate. Examples of other components include active hydrogen group-containing compounds other than the polycarbonate polyol A (such as chain extenders), crosslinking agents, antioxidants, pigments, inorganic fillers, leveling agents, antifoaming agents, flame retardants, catalysts, and plasticizers.

[0076] <Polyurethane resin> Another embodiment of the present disclosure is a polyurethane resin (hereinafter referred to as "polyurethane resin A") formed from the polyurethane resin-forming composition A.

[0077] When the polyurethane resin-forming composition A is a one-component type, the polyurethane resin A can be formed by reacting the polycarbonate polyol with the polyisocyanate by heating the polyurethane resin-forming composition A. When the polyurethane resin-forming composition A is a multi-component type, the polyurethane resin A can be formed by mixing the multiple components that make up the polyurethane resin-forming composition A and reacting the polycarbonate polyol with the polyisocyanate. At least one of the components may be heated before mixing the components, or the mixed component may be heated after mixing the components.

[0078] In one embodiment, the polyurethane resin-forming composition A is a curable composition, and the polyurethane resin is a cured product of the polyurethane resin-forming composition A.

[0079] <Potting material> Another embodiment of the present disclosure is a potting material comprising the polyurethane resin-forming composition A. The potting material is used, for example, to seal electrical and electronic components, etc. Here, electrical and electronic components refer to either or both of electrical and electronic components.

[0080] The potting material can form a sealing portion containing the above-mentioned polyurethane resin A. Therefore, the potting material has excellent heat resistance and low-temperature properties (low-temperature flexibility), and can be suitably used as a potting material for automobiles, particularly for electrical and electronic components (e.g., electrical components such as ECUs) that are mounted outside the vehicle interior, such as in the engine compartment, where the environment is harsh.

[0081] <Sealing body> Another embodiment of the present disclosure is a sealed body including a sealing portion formed from the potting material. The sealed body is, for example, a sealed body including an electric / electronic component, at least a portion of which is sealed by the sealing portion.

[0082] The sealing portion of the sealing body is formed from the potting material, and therefore contains polyurethane resin A, and has excellent heat resistance and low-temperature characteristics (low-temperature flexibility). [Example]

[0083] The present disclosure will be described in more detail below using examples and comparative examples, but the present disclosure is not limited to the following examples.

[0084] <Examples 1 to 17 and Comparative Examples 1 to 12> The polycarbonate polyols of Examples 1 to 17 and Comparative Examples 1 to 12 were synthesized by polycondensation of a polyol and a carbonate. Specifically, first, the polyol and diethyl carbonate shown in Table 1 were charged into a reaction apparatus equipped with a stirrer, thermometer, heater, and distillation column, and tetrabutyl titanate was also charged as a reaction catalyst. The amounts of each component charged were as shown in Table 1. Next, the temperature inside the apparatus was gradually increased to 190°C. When the distillation of ethanol slowed and the temperature at the top of the distillation column fell to 50°C or below, the pressure inside the apparatus was gradually reduced to 0.2 kPa while maintaining the temperature at 190°C, and the reaction was continued for another 8 hours at a pressure of 0.2 kPa. The polycarbonate polyols of Examples 1 to 17 and Comparative Examples 1 to 12 were synthesized by the above-mentioned procedures.

[0085] [Table 1]

[0086] Details of each component shown in Table 1 are as follows: 1,5-PD: 1,5-pentanediol 1,6-HD: 1,6-hexanediol MPD: 3-methyl-1,5-pentanediol 1,9-ND: 1,9-nonanediol 1,10-DD: 1,10-decanediol 1,12-DdD: 1,12-dodecanediol DEC: Diethyl carbonate (Tokyo Chemical Industry Co., Ltd.) TBT: Tetrabutyl titanate The 1,5-PD source, 1,6-HD source, 1,10-DD source, and 1,12-DdD source were products manufactured by Tokyo Chemical Industry Co., Ltd., and the MPD source was a product manufactured by Kuraray Co., Ltd. The 1,9-ND source was ND (trade name) manufactured by Kuraray Co., Ltd.

[0087] (Calculation of average carbon number) The average carbon number (molar average carbon number) of the polyols used in Examples 1 to 17 and Comparative Examples 1 to 12 was calculated from the blending amounts. The results are shown in Tables 2 to 5. The average carbon number of the polyol can also be determined by analyzing the synthesized polycarbonate polyol. In Example 1, the polycarbonate polyol was analyzed by the following method to determine the average carbon number of the polyol, and it was confirmed that the obtained analytical value (measured value) was the same as the value calculated from the blending amounts.

[0088] (Measurement of average carbon number) Approximately 0.1 g of polycarbonate polyol was accurately weighed and dissolved in 5 mL of tetrahydrofuran (THF) in a 300 mL recovery flask. 5 mL of 6 mol / L potassium hydroxide aqueous solution, 45 mL of ethanol, and zeolite were added, and the mixture was refluxed in a water bath for 1 hour. After reflux, the mixture was cooled to room temperature, neutralized with 5 mL of 6 mol / L hydrochloric acid, and then 100 mL of ethanol was added. The solvent was then removed using an evaporator. Chloroform was added to the recovery flask, and the recovery flask was shaken well to wash the recovery flask. The filtrate was collected after filtration, and this process was repeated several times until the filtrate reached 100 mL. The resulting sample solution was analyzed by gas chromatography (GC) under the following conditions, and the molar ratio of the polyol was calculated using a calibration curve for each polyol prepared in advance. The average carbon number was calculated from the obtained molar ratio. Even if the type of polyol constituting the polycarbonate polyol is unknown, the type of the polyol can be identified from mass information obtained by GC / MS analysis. Even in the case of special polyols that cannot be identified from mass information alone, they can be identified by structural analysis (e.g., NMR analysis) of each polyol separated by the GC analysis. [conditions] Equipment: Shimadzu GC-2010 Column: Restek Stabilwax (0.25mmI.D.×30m, df=0.25μm) Column oven temperature: 100℃-10℃ / min-250℃ (5min) Column flow rate: 1.0 mL / min Sample injection port: Split injection port (split ratio = 1 / 30), 250°C Sample injection volume: 1 μL Carrier gas: He Detector (FID) temperature: 250℃

[0089] (Hydroxyl number measurement) The hydroxyl values ​​of the polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 were evaluated by a method using an acetylating reagent in accordance with JIS K1557-1. The results are shown in Tables 2 to 5.

[0090] <Rating 1> (Low temperature flexibility) The glass transition temperatures (Tg) of the polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 were measured. The glass transition temperatures (Tg) were measured in accordance with JIS K6240 under the following conditions. Using the measured glass transition temperatures (Tg), low-temperature flexibility was evaluated according to the following evaluation criteria. A rating of A to E was determined to indicate good low-temperature flexibility. The evaluation results are shown in Tables 2 to 5. [conditions] Measurements were carried out using a DSC8500 manufactured by PerkinElmer in the following steps [1] to [6], and the glass transition temperature (Tg) was determined from the measurement results in step [6]. [1] The sample was rapidly cooled from room temperature (25°C) to -80°C and held at -80°C for 3 minutes. [2] The temperature was increased from -80°C to 100°C at a rate of 10°C / min. [3] Held at 100°C for 3 minutes. [4] The temperature was decreased from 100°C to -80°C at a rate of 10°C / min. [5] Heated at -80°C for 3 minutes. [6] The temperature was increased from -80°C to 100°C at a rate of 10°C / min. [Evaluation criteria] A: The glass transition temperature is -58°C or lower. B: The glass transition temperature is greater than -58°C and equal to or less than -57°C. C: The glass transition temperature is greater than -57°C and equal to or less than -56°C. D: The glass transition temperature is greater than -56°C and less than or equal to -55°C. E: The glass transition temperature is greater than -55°C and equal to or less than -54°C. F: The glass transition temperature is greater than -54°C or the crystallinity is so high that measurement is not possible.

[0091] (Easy to handle) The polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 were heated to 100°C, placed in transparent glass bottles, and left to stand for 10 days in an environment at 15°C. The state of the polycarbonate polyols at 15°C after standing was then confirmed. The state was confirmed visually, and if there was even a slight degree of fluidity when tilted, it was judged to be liquid, and if there was no fluidity, it was judged to be solid. Generally, as the temperature drops, crystallization progresses more easily and it becomes more difficult to maintain a liquid state. Therefore, if the polycarbonate polyol was in a liquid state in this evaluation, it was evaluated as having good handleability at room temperature (25°C ± 10 to 15°C). The evaluation results are shown in Tables 2 to 5.

[0092] (Low temperature stability) The polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 were heated to 100°C, placed in transparent glass bottles, and left to stand under the conditions 1 to 4 below. The state of the polycarbonate polyols after standing was then confirmed. The state was confirmed visually at each temperature condition, and if there was even a slight degree of fluidity when tilted, it was judged to be liquid, and if there was no fluidity, it was judged to be solid. In this evaluation, low-temperature stability was evaluated according to the following criteria. Low-temperature stability was judged to be good when ranked A to D. The evaluation results are shown in Tables 2 to 5. [conditions] 1: Leave at 5℃ for 10 days 2: Leave at 5℃ for 3 months 3: Leave at 0℃ for 10 days 4: Leave at 0°C for 3 months [Evaluation criteria] A: It is liquid under all conditions 1 to 4. B: It is liquid under conditions 1 to 3 and solid under condition 4. C: Liquid under conditions 1 and 2, solid under conditions 3 and 4. D: Liquid under condition 1, solid under conditions 2 to 4. E: Solid under all conditions 1 to 4.

[0093] (Heat resistance) The weight loss rate of the polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 was measured by TGA (thermogravimetric analysis). The weight loss rate was measured under the following conditions. Using the measured weight loss rate, heat resistance was evaluated according to the following evaluation criteria. Heat resistance was determined to be good when the rating was A to E. The evaluation results are shown in Tables 2 to 5. [conditions] Measurements were carried out using the STA7200RV manufactured by Hitachi High-Tech Science Corporation, following the procedure of steps [1] to [4] below, and the weight loss rate when heated in air at 240°C for 60 minutes was calculated from the measurement results of step [4]. [1] 10±0.5 mg of polycarbonate polyol was placed in a weighing device. [2] The air flow rate was set to 200 mL / min. [3] The temperature was increased from 25°C to 240°C at a rate of 75°C / min. [4] Held at 240°C for more than 60 minutes. [Evaluation criteria] A: The weight loss rate is 21% by mass or less. B: The weight loss rate is greater than 21% by mass and equal to or less than 23% by mass. C: The weight loss rate is greater than 23% by mass and equal to or less than 25% by mass. D: The weight loss rate is greater than 25% by mass and equal to or less than 26% by mass. E: The weight loss rate is greater than 26% by mass and equal to or less than 27% by mass. F: The weight loss rate is greater than 27% by mass.

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] [Table 5]

[0098] <Examples 18 and 19> The polyurethanes of Examples 18 and 19 were synthesized using the polycarbonate polyol obtained in Example 3. Specifically, the components shown in Table 6 were thoroughly mixed until homogeneous while heating to 40 to 60°C, and then degassed under reduced pressure. The degassed mixture was poured into a mold preheated to 100 to 120°C and cured by heating at 100 to 120°C for 30 minutes to 1 hour. After demolding from the mold, secondary curing was performed at 40 to 50°C for 12 hours to obtain the polyurethanes (polyurethane-containing compositions) of Examples 18 and 19. The blending amounts of polycarbonate polyol and polyisocyanate were adjusted so that the equivalent ratio of the active hydrogen groups (OH groups) of the polyol to the isocyanate groups (NCO groups) of the polyisocyanate was the value shown in Table 6. The urethane group concentration in the table was calculated from the blending amounts of polycarbonate polyol (active hydrogen group-containing compound) and polyisocyanate (isocyanate group-containing compound).

[0099] <Rating 2> (Initial evaluation) The initial low-temperature properties (low-temperature flexibility) of the polyurethanes obtained in Examples 18 and 19 were evaluated by DMA measurement of the polyurethanes. Specifically, a measurement sample (test piece) measuring 200 mm × 5 mm × 2 mm (thickness) was first prepared. Next, using a DMA7100 manufactured by Hitachi High-Tech Science Corporation, DMA measurement was performed on the measurement sample under conditions of -80°C to 300°C, a heating rate of 2°C / min, and a frequency of 1 Hz, and the storage modulus (E') and tan δ peak temperature at -40°C were determined. The results are shown in Table 6.

[0100] Furthermore, the Shore A hardness of the polyurethane was measured using an A-type hardness tester in accordance with JIS K 6253. The measurement sample used was Φ30 mm×13 m (height).

[0101] (Evaluation after durability test) Measurement samples prepared in the same manner as in the initial evaluation were subjected to a durability test (A) at 150°C for 2000 hours and a durability test (B) at 85°C / 85% RH. DMA measurements and Shore A hardness measurements were then performed in the same manner as in the initial evaluation to determine the storage modulus (E'), tan δ peak temperature, and Shore A hardness at -40°C. The storage modulus (E'), tan δ peak temperature, and Shore A hardness obtained in the initial evaluation and the storage modulus (E'), tan δ peak temperature, and Shore A hardness obtained in the evaluation after the durability test were then used to calculate the rate of change in storage modulus (E'), the rate of change in tan δ peak temperature, and the rate of change in Shore A hardness. The same measurement samples (Φ30 mm × 13 m (height)) as used in the Shore A hardness evaluation were also used to calculate the rate of weight change from before and after the durability test. The results are shown in Table 6.

[0102] [Table 6]

[0103] Details of the polyisocyanates, catalysts and additives listed in Table 6 are as follows: [Polyisocyanate] Polyisocyanate 1: Isocyanurate-modified hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name: Coronate HXLV ("Coronate" is a registered trademark), NCO content 23.1%) Polyisocyanate 2: A mixture of an isocyanurate-modified hexamethylene diisocyanate and an allophanate-modified hexamethylene diisocyanate, synthesized by the following method: [catalyst] DOTDL: Dioctyl tin dilaurate (Kishida Chemical Co., Ltd.) U-600: Bismuth tris(2-ethylhexanoate) (manufactured by Nitto Kasei Co., Ltd., product name: Neostan U-600 ("Neostan" is a registered trademark)) [Additives] Mixture A: A mixture of IRGANOX-1010 (pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, BASF, trade name), Tinuvin 770 (bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, BASF, trade name), and Adekastab 1500 (tetra-C12-15 alkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite), ADEKA Corporation, trade name) (mass ratio = 1:1:1) Mixture B: a mixture of IRGANOX-1010 (pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, trade name, manufactured by BASF), Tinuvin 123 (bis[2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl]decanedioate, trade name, manufactured by BASF), and Adekastab 2013 (alkyl aryl phosphite, trade name, manufactured by ADEKA Corporation) (mass ratio = 1:1:1)

[0104] <Synthesis of Polyisocyanate 2> A four-neck flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with 730 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation) and 65 g of tridecanol (manufactured by KH Neochem Co., Ltd.), and the reaction was carried out at 80 °C for 1 hour. Subsequently, 0.2 g of stannous octoate (manufactured by Nippon Chemical Industry Co., Ltd.) was added to the reaction solution, and the reaction was carried out at 90 °C until a predetermined NCO content was reached. Then, 0.2 g of an acidic phosphate ester (manufactured by Johoku Chemical Industry Co., Ltd., product name: JP-508) was added as a reaction terminator, and the reaction was stopped at 50 °C for 1 hour. Excess HDI was removed from the reaction product by thin-film distillation (conditions: 140 °C, 0.04 kPa), yielding a modified polyisocyanate (Polyisocyanate 2) with an NCO content of 17.7 wt%, a free HDI content of 0.1 wt%, and a mass ratio of isocyanurate-modified to allophanate-modified of 45:55. The mass ratio of the isocyanurate-modified product to the allophanate-modified product was determined by the following measurement method. (Measurement method) 1Using a H-NMR (JEOL, JNM-ECZ400S / L1), the mass ratio of the isocyanurate-modified product to the allophanate-modified product was determined from the area ratio of the signal of the hydrogen atom bonded to the nitrogen atom of the allophanate group at around 8.5 ppm to the signal of the hydrogen atom of the methylene group adjacent to the nitrogen atom of the isocyanurate group at around 3.7 ppm. The specific measurement conditions are as follows: ·Measurement temperature: 23℃ Sample concentration: 0.1g / 1ml Number of times accumulated: 16 Relaxation time: 5 seconds Solvent: Deuterated dimethyl sulfoxide Chemical shift reference: Deuterium signal of hydrogen atom of methyl group in dimethyl sulfoxide (2.5 ppm)

[0105] The polyurethanes obtained in Examples 18 and 19 were confirmed to have excellent low-temperature flexibility and sufficiently high hardness in the initial evaluation. Furthermore, the rate of change in storage modulus (E') at -40°C, the amount of change in tan δ peak temperature, the rate of change in Shore A hardness, and the rate of change in weight before and after the durability test (A) and the durability test (B) were all small, confirming that the polyurethanes have excellent long-term reliability.

Claims

[Claim 1] A polycarbonate polyol containing multiple types of polyols as monomer units, the polyol constituting the monomer units contains at least two types of linear glycols and at least one type of branched glycol; the polyol has an average carbon number of 6.5 to 10, the branched glycol comprises 3-methyl-1,5-pentanediol; The polycarbonate polyol has a 3-methyl-1,5-pentanediol content of 2 to 44 mol %.

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