Polycarbonate polyol, polyurethane resin-forming composition, potting material, polyurethane resin, and sealant

Abstract

A polycarbonate polyol containing a plurality of kinds of polyols as monomer units, wherein the polyols constituting the monomer units contain at least two kinds of linear glycols and at least one kind of branched glycol, the average number of carbon atoms in the polyols is 6.5-10, the branched glycol contains 3-methyl-1,5-pentanediol, and the content of 3-methyl-1,5-pentanediol in the polyols is 2-44 mol%.

Description

Technical Field

[0001] The present disclosure relates to a polycarbonate polyol, a polyurethane resin-forming composition, a potting material, a polyurethane resin, and a sealing body.

Background Art

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

[0003] However, general polycarbonate polyols (for example, polycarbonate polyols mainly made from 1,6-hexanediol) have high crystallinity and are solid at room temperature (25°C ± 10 - 15°C), so there are problems with workability. For example, when synthesizing a polyurethane resin by mixing a polycarbonate polyol with an isocyanate, operations such as heating to about 80°C to make the polycarbonate polyol liquid or using a large amount of solvent to dissolve the polycarbonate polyol are required.

[0004] From the above circumstances, studies have been conducted to make polycarbonate polyols liquid at room temperature without sacrificing 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

Summary of the Invention

[0006] However, the polycarbonate polyol described in 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 this 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 this disclosure aims to provide a polyurethane resin-forming composition, potting material, polyurethane resin, and sealant obtained from the polycarbonate polyol. [Means for solving the problem]

[0008] This disclosure provides, in several respects, the following [1] to

[18] .

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

[0010] [2] The polycarbonate polyol according to [1], wherein the polyol comprises a first linear glycol having 7 or fewer 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 glycol 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 glycol 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] , having 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 contains a non-aromatic polyisocyanate.

[0022]

[14] The polyurethane resin-forming composition according to

[13] , wherein the non-aromatic polyisocyanate contains an isocyanurate-modified product of an 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] [[ID=asc="48"]]A sealed body comprising a sealed portion formed from the potting material according to

[17] . [Effect of the Invention]

[0027] According to one aspect of this disclosure, a polycarbonate polyol that is easy to handle at room temperature and has excellent heat resistance and low-temperature flexibility can be provided. According to another aspect of this disclosure, a polyurethane resin-forming composition, potting material, polyurethane resin, and sealant obtained from the polycarbonate polyol can also be provided. [Modes for carrying out the invention]

[0028] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. Unless otherwise explicitly stated, the units of the numbers before and after "~" are the same. In numerical ranges described in stages within this specification, the upper or lower limit of one stage may be replaced with the upper or lower limit of another stage. Furthermore, in numerical ranges described within this specification, the upper or lower limit of a range may be replaced with the values ​​shown in the examples. Additionally, individually described upper and lower limits can be combined in any way.

[0029] The embodiments of this disclosure are described below. However, this disclosure is not limited in any way to the embodiments described below.

[0030] <Polycarbonate polyol> One embodiment of the present disclosure is a polycarbonate polyol (hereinafter referred to as "polycarbonate polyol A") 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 polyol 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 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. This compound has a structure in which multiple monomer units made of polyol are connected via carbonate groups. A "monomer unit" is the smallest unit that makes up a polymer and does not contain a carbonate group. A "glycol" is a compound having a structure in which two carbon atoms of a chain aliphatic hydrocarbon or a cyclic aliphatic hydrocarbon are each substituted with one hydroxyl group. Furthermore, the content in polyol refers to the content relative to the total amount of polyol.

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

[0033] Polycarbonate polyol A is, for example, a reaction product (polycondensate) obtained by a transesterification (polycondensation) reaction between the above-mentioned polyol (a polyol containing at least two linear glycols and at least one branched glycol, with an average carbon number of 6.5 to 10, where the branched glycol contains 3-methyl-1,5-pentanediol, and the 3-methyl-1,5-pentanediol content is 2 to 44 mol%) and a carbonate. In the transesterification reaction between a polyol and a carbonate, a compound is formed containing polyol residues (residues obtained by removing n hydroxyl groups from the polyol) and a carbonate group (-OC(=O)O-). When the polyol used as the reaction raw material is a monomer (nonpolymer) such as a glycol, the residues obtained by removing n hydroxyl groups from the monomer become monomer units. Hereinafter, n is determined by the number of hydroxyl groups contained in the polyol. If the polyol is a diol, n is 1 or 2; if the polyol is a triol, n is an integer between 1 and 3.

[0034] (Polyol) The polyol comprises at least two linear glycols and at least one branched glycol. That is, the polycarbonate polyol has a continuous monomer unit via a carbonate group (-OC(=O)O-), as defined by formula: -R 1 -[R in the formula] 1 represents a linear aliphatic hydrocarbon group. It consists of two or more monomer units represented by ] and the formula:-R 2 -[R in the formula] 2 represents a branched aliphatic hydrocarbon group. It includes one or more monomer units represented by ] and .

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

[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, when a linear glycol with 7 or fewer carbon atoms (hereinafter referred to as "first linear glycol") is combined with a linear glycol with 8 or more carbon atoms (hereinafter referred to as "second linear glycol"), the heat resistance and low-temperature flexibility of the polycarbonate polyol tend to be further improved. This tendency is particularly pronounced 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 especially pronounced 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 the combination of 1,6-hexanediol and 1,9-nonanediol, the combination of 1,6-hexanediol and 1,10-decanediol, the combination of 1,6-hexanediol and 1,11-undecanediol, and the 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, the above effect tends to be more pronounced when 1,9-nonanediol is used.

[0039] The content of the first linear glycol in the polyol (i.e., the ratio of monomer units consisting of the first linear glycol to the total 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 handlingability 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 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 ratio of monomer units consisting of the second linear glycol to the total 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 handlingability of the polycarbonate polyol. From these viewpoints, the content of the second linear glycol in the polyol may be, for example, 10-97 mol%, 12-90 mol%, 14-80 mol%, 16-70 mol%, 18-60 mol%, 20-50 mol%, 20-45 mol%, 20-40 mol%, 20-35 mol%, or 20-30 mol%. In this embodiment, from the same viewpoint as above, the content of linear glycols 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 handling properties 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 handling properties of the polycarbonate polyol. From these viewpoints, the above 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 branched glycol types contained in the polyol may be 1 to 3, 1 to 2, or 1. The number of carbon atoms in the branched glycol may be, for example, 3 to 20, 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, 1,12-octadecanediol, and the like.

[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, and may be 95 mol% or more or 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 to the total monomer units consisting of the polyol) is 2 to 44 mol%. From the viewpoint of improving the handling properties and low-temperature stability of the polycarbonate polyol, 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 heat resistance and low-temperature flexibility of the polycarbonate polyol, it 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 these perspectives, the content of 3-methyl-1,5-pentanediol in the polyol may be, for example, 3-42 mol%, 5-40 mol%, 6-37 mol%, 8-34 mol%, 10-31 mol%, 12-28 mol%, or 14-28 mol%.

[0045] The molar ratio of linear glycol to branched glycol in a polyol (linear glycol / branched glycol) may be 1.2 or higher, 1.3 or higher, 1.6 or higher, 1.7 or higher, 1.9 or higher, 2.1 or higher, 2.5 or higher, or 2.8 or higher, from the viewpoint of improving the heat resistance of the polycarbonate polyol, and may be 49 or lower, 24 or lower, 16 or lower, 12 or lower, 9 or lower, 7 or lower, 6 or lower, or 5 or lower, from the viewpoint of improving the handling properties of the polycarbonate polyol. From these viewpoints, the above 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 linear glycol having 6 to 12 carbon atoms to the content of 3-methyl-1,5-pentanediol may be within the above range, and the molar ratio of the content of linear glycol having 6 to 10 carbon atoms to the content of 3-methyl-1,5-pentanediol may be within the above 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 handlingability of the polycarbonate polyol. From these viewpoints, the above 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 linear glycol having 6 to 7 carbon atoms to the content of 3-methyl-1,5-pentanediol may be within 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 within the above range.

[0047] The molar ratio of the content of a second linear glycol to the content of a branched glycol in a 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 handling properties of the polycarbonate polyol. From these viewpoints, the above 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 linear glycols having 8 to 12 carbon atoms to the content of 3-methyl-1,5-pentanediol may be within the above 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 within the above range.

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

[0049] Polyols may contain polyols other than glycols (polyols with 3 or more hydroxyl groups), but from the viewpoint of improving the low-temperature flexibility of polycarbonate polyols, the glycol content in the polyol may be 90 mol% or more, 95 mol% or more, or 100 mol%. A polycarbonate polyol with a glycol content of 100 mol% is a polycarbonate diol. Furthermore, from the viewpoint of improving the heat resistance of polycarbonate polyols, the glycol content of polyols with 6 or more carbon atoms 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 polycarbonate polyols, the glycol content of polyols with 6 to 12 carbon atoms may be 90 mol% or more, 95 mol% or more, or 100 mol%.

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

[0051] (Carbonate) The carbonate may include one or more carbonates. The carbonate may be any compound capable of condensing with a polyol to produce a polycarbonate polyol. Examples of carbonates 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, diantlyl carbonate, diphenanthryl carbonate, diindanyl carbonate, and bistetrahydronaphthyl carbonate.

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

[0053] The molecular weight of polycarbonate polyol A may be 600 or more, 1000 or more, or 1500 or more, from the viewpoint of lowering the urethane group concentration of the polyurethane resin and improving the low-temperature flexibility of the polyurethane resin. The molecular weight of 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 polycarbonate polyol A may be 600 to 4000, 1000 to 3500, or 1500 to 3000. The above molecular weights are values ​​calculated from the hydroxyl value and number of hydroxyl groups of polycarbonate polyol A. The number of hydroxyl groups of polycarbonate polyol is, for example, 2 to 3.

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

[0055] The glass transition temperature (Tg) of 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 polycarbonate polyol A is, for example, -65°C. That is, the glass transition temperature (Tg) of 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 polyol and carbonate described above by a transesterification reaction. In this step, for example, in a reaction apparatus equipped with a stirrer, thermometer, heating device and distillation column, under a nitrogen stream, the temperature is gradually increased to 190°C while distilling off ethanol, and the pressure is then gradually reduced to 0.5 kPa or less, and the reaction is carried out at a pressure of 0.5 kPa or less for 4 hours or more to carry out the polycondensation reaction between the polyol and carbonate. The mixing ratio of polyol and carbonate can be appropriately adjusted from the viewpoint of the hydroxyl value of the polycarbonate polyol and the volatility of the carbonate.

[0057] The polycarbonate polyol A described above is suitably used as a polyol for forming polyurethane resins. By using polycarbonate polyol A, polyurethane resins with excellent 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 A contained in the polycarbonate polyol composition may be one type or multiple types. The polycarbonate polyol composition may consist only of polycarbonate polyol A, or it may contain components other than polycarbonate polyol A.

[0060] The polycarbonate polyol composition may contain by-products and unreacted raw materials (polyol, carbonate, catalyst, etc.) that are introduced during the manufacturing process of the above-mentioned polycarbonate polyol A. The polycarbonate polyol composition may also contain other components described later.

[0061] The content of polycarbonate polyol A in the polycarbonate polyol composition may be 60-100% by mass, 70-95% by mass, or 80-90% by 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 method for producing polycarbonate polyol A (a reaction mixture obtained by a transesterification reaction between a polyol and a carbonate, comprising at least two linear glycols and at least one branched glycol, with an average carbon number of 6.5 to 10, wherein the branched glycol contains 3-methyl-1,5-pentanediol, and the content of 3-methyl-1,5-pentanediol is 2 to 44 mol%).

[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") comprising the polycarbonate polyol A and a polyisocyanate.

[0064] According to polyurethane resin-forming composition A, a polyurethane resin with excellent heat resistance and low-temperature properties (low-temperature flexibility) can be easily formed. Because this polyurethane resin has excellent heat resistance, it is less prone to weight loss due to heat and tends to maintain excellent low-temperature properties over a long period of time. Furthermore, the polyurethane resin obtained from polyurethane resin-forming composition A tends to have good hardness and tends to maintain hardness over a long period of time.

[0065] The polycarbonate polyol A and polyisocyanate contained in polyurethane resin-forming composition A may be one type or multiple types. Polyurethane resin-forming composition A may also contain the above-mentioned polycarbonate polyol composition.

[0066] The polyisocyanate is not particularly limited, and a wide range of known polyisocyanates can be used. In particular, when using polyisocyanates without aromatic rings (non-aromatic polyisocyanates), 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-methylpentane-1,5-diisocyanate, 3-methylpentane-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-trimethylhexa Examples 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 aliphatic polyisocyanate derivatives include isocyanurate-modified derivatives, allophanate-modified derivatives, biuret-modified derivatives, urethane-modified derivatives, urea-modified derivatives, carbodiimide-modified derivatives, uretonimine-modified derivatives, and uretdione-modified derivatives.

[0068] Using derivatives of aliphatic polyisocyanates as non-aromatic polyisocyanates makes it easier to achieve a higher level of both heat resistance and flexibility in low-temperature environments. In particular, using isocyanurate-modified aliphatic polyisocyanates tends to yield higher heat resistance, while using allophanate-modified aliphatic polyisocyanates tends to improve flexibility in low-temperature environments.

[0069] The content of the above-mentioned isocyanurate modified material 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 having superior flexibility in low-temperature environments. From these viewpoints, the content of the above-mentioned isocyanurate modified material may be 10-100% by mass, 10-99.9% by mass, 20-99% by mass, 30-99% by mass, 30-95% by mass, or 50-95% by mass. In particular, when the content of the above-mentioned isocyanurate modified material is 60-100% by mass, there is a tendency for superior heat resistance. Note that the above content is based on the total mass of the polyisocyanate.

[0070] The content of the allophanate modified material 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 material 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. Note that the above content is based on the total mass of polyisocyanate.

[0071] Non-aromatic polyisocyanates do not need to have urethane groups, as they offer superior flexibility in low-temperature environments. Similarly, polyurethane resin-forming compositions do not need to contain polyurethane polyisocyanates.

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

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

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

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

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

[0077] If polyurethane resin-forming composition A is a one-component type, polyurethane resin A can be formed by heating polyurethane resin-forming composition A to react the polycarbonate polyol with polyisocyanate. If polyurethane resin-forming composition A is a multi-component type, polyurethane resin A can be formed by mixing multiple liquids constituting polyurethane resin-forming composition A to react the polycarbonate polyol with polyisocyanate. At least one liquid may be heated before mixing the liquids, or the mixed liquid may be heated after mixing the liquids.

[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 described above. This potting material is used, for example, for sealing electrical and electronic components. Here, electrical and electronic components mean either or both electrical components and / or electronic components.

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

[0081] <Sealing body> Another embodiment of the present disclosure is a seal comprising a sealing portion formed from the potting material. The seal comprises, for example, an electrical and electronic component, wherein at least a portion of the electrical and electronic component is sealed by the sealing portion.

[0082] Since the sealing portion of the above-mentioned sealant is formed from the potting material, the sealing portion contains polyurethane resin A and has excellent heat resistance and low-temperature properties (low-temperature flexibility). [Examples]

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

[0084] <Examples 1-17 and Comparative Examples 1-12> Polycarbonate polyols of Examples 1-17 and Comparative Examples 1-12 were synthesized by polycondensation of polyols and carbonates. Specifically, first, the polyols and diethyl carbonates shown in Table 1 were charged into a reaction apparatus equipped with a stirrer, thermometer, heating device, and distillation column, and tetrabutyl titanate was further 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 down and the top temperature of the distillation column fell below 50°C, the temperature inside the apparatus was kept at 190°C, and the pressure was gradually reduced to 0.2 kPa, and the reaction was continued at a pressure of 0.2 kPa for a further 8 hours. Through the above operations, polycarbonate polyols of Examples 1-17 and Comparative Examples 1-12 were synthesized.

[0085] [Table 1]

[0086] The 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 (manufactured by Tokyo Chemical Industry Co., Ltd.) TBT: Tetrabutyl titanate Products manufactured by Tokyo Chemical Industry Co., Ltd. were used as the 1,5-PD source, 1,6-HD source, 1,10-DD source, and 1,12-DdD source, and a product manufactured by Kuraray Co., Ltd. was used as the MPD source. ND (product name) manufactured by Kuraray Co., Ltd. was used as the 1,9-ND source.

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

[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 round-bottom flask. Then, 5 mL of 6 mol / L potassium hydroxide aqueous solution, 45 mL of ethanol, and boiling chips were added, and the mixture was refluxed in a water bath for 1 hour. After refluxing, 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 round-bottom flask, and the mixture was shaken well. While washing the flask, the filtrate after filtration was collected, 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 each polyol was calculated from the calibration curves prepared in advance. The average number of carbon atoms was calculated from the obtained molar ratios. Furthermore, even if the type of polyol constituting the polycarbonate polyol is unknown, the type of polyol can be identified from the mass information obtained by GC / MS analysis. In the case of special polyols that cannot be identified by 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℃ (5 min) Column flow rate: 1.0 mL / min Sample inlet: Split inlet (split ratio = 1 / 30), 250°C Sample injection volume: 1 μL Carrier gas: He Detector (FID) temperature: 250℃

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

[0090] <Rating 1> (Low temperature flexibility) The glass transition temperature (Tg) of the polycarbonate polyols obtained in Examples 1-17 and Comparative Examples 1-12 was measured. The glass transition temperature (Tg) was measured in accordance with JIS K6240 under the following conditions. Using the measured glass transition temperature (Tg), low-temperature flexibility was evaluated according to the evaluation criteria below. Low-temperature flexibility was judged to be good if the evaluation was A to E. The evaluation results are shown in Tables 2-5. [conditions] Using a PerkinElmer DSC8500, measurements were performed according to the following steps [1] to [6], and the glass transition temperature (Tg) was determined from the measurement results in step [6]. [1] The samples were 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 heating rate of 10°C / min. [3] It was held at 100°C for 3 minutes. [4] The temperature was lowered from 100°C to -80°C at a rate of 10°C / min. [5] -80°C was maintained for 3 minutes. [6] The temperature was increased from -80°C to 100°C at a heating 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 less than or equal to -57°C. C: The glass transition temperature is greater than -57°C and less than or equal to -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 less than or equal to -54°C. F: Glass transition temperature is greater than -54°C, or crystallinity is too high to measure.

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

[0092] (Low temperature stability) The polycarbonate polyols obtained in Examples 1-17 and Comparative Examples 1-12 were heated to 100°C, placed in transparent glass bottles, and allowed to stand under the conditions 1-4 below. The state of the polycarbonate polyols after standing was then checked. The state was checked visually at the temperature under each condition. If there was even a slight 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 if the evaluation was A-D. The evaluation results are shown in Tables 2-5. [conditions] 1: Leave to stand at 5°C for 10 days 2: Leave undisturbed at 5°C for 3 months. 3: Leave standing at 0°C for 10 days 4: Leave undisturbed at 0°C for 3 months [Evaluation Criteria] A: It is liquid under any of conditions 1-4. B: It is liquid under conditions 1-3 and solid under condition 4. C: It is liquid under conditions 1 and 2, and solid under conditions 3 and 4. D: It is liquid under condition 1 and solid under conditions 2-4. E: It is a solid under any of conditions 1-4.

[0093] (Heat resistance) The weight loss rate of the polycarbonate polyols obtained in Examples 1-17 and Comparative Examples 1-12 was measured by TGA (thermogravimetric analysis). The weight loss rate was measured under the following conditions. The heat resistance was evaluated using the measured weight loss rate according to the evaluation criteria below. A rating of A to E indicated good heat resistance. The evaluation results are shown in Tables 2-5. [conditions] Using the STA7200RV manufactured by Hitachi High-Tech Science Corporation, measurements were performed according to the following steps [1] to [4], and the weight loss rate when heated in air at 240°C for 60 minutes was determined from the measurement results in step [4]. [1] 10 ± 0.5 mg of polycarbonate polyol was placed in a weighing device. [2] The airflow 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] The temperature was maintained at 240°C for at least 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 less than or equal to 23% by mass. C: The weight loss rate is greater than 23% by mass and less than or equal to 25% by mass. D: The weight loss rate is greater than 25% by mass and less than or equal to 26% by mass. E: The weight loss rate is greater than 26% by mass and less than or equal to 27% by mass. F: 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> Polyurethanes for 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 being heated to 40-60°C, and then degassed under reduced pressure. The degassed mixture was poured into a mold preheated to 100-120°C and cured by heating at 100-120°C for 30 minutes to 1 hour. After demolding from the mold, the polyurethanes (polyurethane-containing compositions) for Examples 18 and 19 were obtained by secondary curing at 40-50°C for 12 hours. The 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 as shown in Table 6. The urethane group concentration in the table was calculated from the 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, first, a measurement sample (test piece) measuring 200 mm × 5 mm × 2 mm (thickness) was prepared. Next, using a DMA7100 manufactured by Hitachi High-Tech Science Corporation, DMA measurements were performed on the measurement sample under the conditions of -80°C to 300°C, heating rate of 2°C / min, and frequency of 1 Hz, and the storage modulus (E') and tanδ 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 a Type A hardness tester in accordance with JIS K6253. The sample used for measurement was Φ30mm × 13m (height).

[0101] (Evaluation after durability testing) For measurement samples prepared in the same manner as the initial evaluation described above, durability tests were conducted: (A) heating at 150°C for 2000 hours, and (B) heating at 85°C / 85%RH. Afterward, DMA measurements and Shore A hardness measurements were performed in the same manner as the initial evaluation, and the storage modulus (E'), tanδ peak temperature, and Shore A hardness at -40°C were determined. Next, using the storage modulus (E'), tanδ peak temperature, and Shore A hardness obtained in the initial evaluation and the storage modulus (E'), tanδ peak temperature, and Shore A hardness obtained in the post-durability evaluation, the rate of change in storage modulus (E'), the change in tanδ peak temperature, and the rate of change in Shore A hardness were calculated. Furthermore, the rate of weight change was calculated from the weight before and after the durability test using the same measurement sample (Φ30mm × 13m (height)) as used for the Shore A hardness evaluation. The results are shown in Table 6.

[0102] [Table 6]

[0103] The details of the polyisocyanates, catalysts, and additives listed in Table 6 are as follows. [Polyisocyanate] • Polyisocyanate 1: Isocyanurate modified form of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name: Coronate HXLV ("Coronate" is a registered trademark), NCO content 23.1%) • Polyisocyanate 2: A mixture of isocyanurate-modified hexamethylene diisocyanate and allophanate-modified hexamethylene diisocyanate, synthesized by the following method. [catalyst] • DOTDL: Dioctyl tin dilaurate (manufactured by Kishida Chemical Co., Ltd.) • U-600: Bismastris (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, manufactured by BASF, trade name), Tinuvin 770 (bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, manufactured by BASF, trade name), and Adekastab 1500 (tetra-C12-15 alkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite), manufactured by 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, manufactured by BASF, trade name), Tinuvin 123 (bis[2,2,6,6-tetramethyl-1-(octyloxy)piperidine-4-yl] decandioate, manufactured by BASF, trade name), and Adekastab 2013 (alkylallyl phosphite, manufactured by ADEKA Corporation, trade name) (mass ratio = 1:1:1)

[0104] <Synthesis of Polyisocyanate 2> In a four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, 730 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation) and 65 g of tridecanol (manufactured by KH Neochem Co., Ltd.) were charged and reacted at 80°C for 1 hour. Subsequently, 0.2 g of tin octoate (manufactured by Nippon Chemical Industrial Co., Ltd.) was added to the reaction solution and the reaction was carried out at 90°C until the desired NCO content was reached. Then, 0.2 g of acidic phosphate ester (manufactured by Johoku Chemical Industry Co., Ltd., product name: JP-508), a reaction stopper, was added and the reaction was stopped at 50°C for 1 hour. From this reaction product, excess HDI was removed by thin-film distillation (conditions: 140°C, 0.04 kPa) to obtain a modified polyisocyanate (polyisocyanate 2) with an NCO content of 17.7% by mass, a free HDI content of 0.1% by mass, and an isocyanurate modified form:allophanate modified form ratio of 45:55 (by mass). The mass ratio of isocyanurate-modified and allophanate-modified products was determined by the following measurement method. (Measurement method) 1Using 1H-NMR (JEOL, JNM-ECZ400S / L1), the mass ratio of the isocyanurate-modified and allophanate-modified compounds was determined from the area ratio of the signal of the hydrogen atom bonded to the nitrogen atom of the allophanate group at approximately 8.5 ppm and the signal of the hydrogen atom of the methylene group adjacent to the nitrogen atom of the isocyanurate group at approximately 3.7 ppm. The specific measurement conditions are as follows. ·Measurement temperature: 23℃ • Sample concentration: 0.1g / 1ml • Total number of times: 16 • Relaxation time: 5 seconds • Solvent: Deuterium dimethyl sulfoxide • Chemical shift criterion: Signal of hydrogen atoms of the methyl group in deuterium 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 initial evaluations. Furthermore, the polyurethanes showed excellent long-term reliability, with small changes in storage modulus (E') at -40°C, tanδ peak temperature, Shore A hardness, and weight before and after durability tests (A) and (B).

Claims

1. A polycarbonate polyol containing multiple types of polyols as monomer units, The polyol constituting the monomer unit comprises at least two linear glycols and at least one branched glycol. The average number of carbon atoms in the polyol is 6.5 to 10. The polyol comprises 1,6-hexanediol, which is a first linear glycol having 7 or fewer carbon atoms; 1,9-nonanediol, which is a second linear glycol having 8 or more carbon atoms; and 3-methyl-1,5-pentanediol, which is the branched glycol. The 1,6-hexanediol content in the polyol is 40 to 65 mol%, The content of 3-methyl-1,5-pentanediol in the polyol is 20 to 44 mol%, A polycarbonate polyol (excluding those containing 0.05 to 25% by weight of silicon atoms) in which the molar ratio of the content of the second linear glycol to the content of the branched glycol in the polyol is 0.2 to 1.

2.

2. The polycarbonate polyol according to claim 1, wherein the content of the second linear glycol in the polyol is 16 to 30 mol%.

3. The polycarbonate polyol according to claim 1, wherein the molar ratio of the content of the first linear glycol to the content of the second linear glycol in the polyol is 1.5 to 3.

0.

4. The polycarbonate polyol according to claim 1, wherein the molar ratio of the content of linear glycol to the content of branched glycol in the polyol is 1.2 to 5.

5. The polycarbonate polyol according to claim 1, wherein the hydroxyl value is 30 to 180 mg KOH / g.

6. A polyurethane resin-forming composition comprising a polycarbonate polyol according to any one of claims 1 to 5 and a polyisocyanate.

7. The polyurethane resin-forming composition according to claim 6, wherein the polyisocyanate comprises a non-aromatic polyisocyanate.

8. The polyurethane resin-forming composition according to claim 7, wherein the non-aromatic polyisocyanate includes an isocyanurate-modified aliphatic polyisocyanate.

9. The polyurethane resin-forming composition according to claim 8, wherein the content of the isocyanurate modified material is 60 to 100% by mass, based on the total mass of the polyisocyanate.

10. A polyurethane resin formed from the polyurethane resin-forming composition described in claim 6.

11. A potting material comprising the polyurethane resin-forming composition described in claim 6.

12. A sealing body comprising a sealing portion formed from the potting material described in claim 11.

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