Polycarbonate polyol, polyurethane resin-forming composition, potting material, polyurethane resin, and sealing body

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

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

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

[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, general polycarbonate polyols (for example, polycarbonate polyols made primarily from 1,6-hexanediol) have high crystallinity and are solid at room temperature (25°C ± 10 to 15°C), which poses workability issues. 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.

[0005] Japanese Patent Application Publication No. 02-289616

[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 a low-temperature environment (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.

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

[18] .

[0009] [1] A polycarbonate polyol 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%.

[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 includes 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] , having a hydroxyl value of 30 to 180 mg KOH / 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] A sealed body comprising a sealing part formed from the potting material according to

[17] .

[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.

[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 limit or lower limit of a numerical range in a certain stage may be replaced with the upper limit or lower limit of a numerical range in another stage. Furthermore, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples. Furthermore, the upper limit and lower limit values ​​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 containing multiple types of polyols as monomer units, in which the polyols constituting the monomer units contain 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 contains 3-methyl-1,5-pentanediol, and the content of 3-methyl-1,5-pentanediol in the polyol is 2 to 44 mol% (hereinafter referred to as "polycarbonate polyol A").

[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. 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 an extended 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 less likely to lose weight due to heating. That is, polycarbonate polyol A has excellent heat resistance (resistance to oxidative degradation). 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] 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 and the 3-methyl-1,5-pentanediol content is 2 to 44 mol%) and carbonate. In the transesterification reaction between a polyol and a carbonate, a compound containing a polyol residue (a residue obtained by removing n hydroxyl groups from a polyol) and a carbonate group (—OC(═O)O—) is formed. When the polyol used as the reaction raw material is a monomer (non-polymer) such as glycol, the residue obtained by removing n hydroxyl groups from the monomer becomes the monomer unit. Note that 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 from 1 to 3.

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

[0035] The number of types of linear glycol contained in the polyol may be 2 to 4, 2 to 3, or even 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 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 be able to maintain a liquid state 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, when a linear glycol having 7 or less carbon atoms (hereinafter referred to as a "first linear glycol") is combined with a linear glycol having 8 or more carbon atoms (hereinafter referred to as a "second linear glycol"), the heat resistance and low-temperature flexibility of the polycarbonate polyol tend to be further improved. 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 in 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 in the above range, and the content of 1,6-hexanediol may be in 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 in 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 in the above range, and the total content of 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol may be in 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, 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 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-mentioned 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-mentioned 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 the present 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); however, 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 includes one type of carbonate or two or more types of carbonate. 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. Furthermore, 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, and 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 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] (Production Method) The production method of 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, in a reactor equipped with a stirrer, a thermometer, a heating device, and a distillation column, 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, 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 of the polyol and carbonate. The blending ratio of the polyol and the carbonate can be appropriately adjusted in view 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 containing 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 polycarbonate polyol A and a polyisocyanate.

[0064] The polyurethane resin-forming composition A can easily form a polyurethane resin having excellent heat resistance and low-temperature properties (low-temperature flexibility). Because of its excellent heat resistance, the polyurethane resin 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 derivatives thereof. 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 substance 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 substance 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 substance 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 compound may be 0.01% by mass or more, 1% by mass or more, or 5% by mass or more from the viewpoint of achieving 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 achieving higher heat resistance. From these viewpoints, the content of the allophanate-modified compound 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 means 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 liquids 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 from 50 to 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 and 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 and 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 components 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] 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).

[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 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, a reaction apparatus equipped with a stirrer, a thermometer, a heating device, and a distillation column was charged with the polyol and diethyl carbonate shown in Table 1, 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 less, 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 an additional 8 hours at a pressure of 0.2 kPa. By the above procedures, the polycarbonate polyols of Examples 1 to 17 and Comparative Examples 1 to 12 were synthesized.

[0085]

[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 (manufactured by 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 used were products manufactured by Tokyo Chemical Industry Co., Ltd., and the MPD source used was a product manufactured by Kuraray Co., Ltd. The 1,9-ND source used 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 blended 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 blended amounts.

[0088] (Measurement of Average Carbon Number) Approximately 0.1 g of polycarbonate polyol was 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 by adding 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 from the calibration curves for each polyol prepared in advance. The average carbon number was calculated from the resulting molar ratio.

[0043] 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 a special polyol that cannot be identified from mass information alone, it can be identified by structural analysis (e.g., NMR analysis) of each polyol separated by the GC analysis. [Conditions] Apparatus: Shimadzu GC-2010 Column: Restek Stabilwax (0.25 mm I.D. x 30 m, df = 0.25 μm) Column oven temperature: 100°C - 10°C / min - 250°C (5 min) Column flow rate: 1.0 mL / min Sample injection port: Split injection port (split ratio = 1 / 30), 250°C Sample injection amount: 1 μL Carrier gas: He Detector (FID) temperature: 250°C

[0089] (Hydroxyl Value 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] <Evaluation 1> (Low-Temperature Flexibility) The glass transition temperature (Tg) of the polycarbonate polyols obtained in Examples 1 to 17 and Comparative Examples 1 to 12 was measured. The glass transition temperature (Tg) was measured in accordance with JIS K6240 under the following conditions. The measured glass transition temperature (Tg) was used to evaluate low-temperature flexibility 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 PerkinElmer DSC8500 in the following steps [1] to [6], and the glass transition temperature (Tg) was determined from the measurement result in step [6]. [1] Rapid cooling from room temperature (25°C) to -80°C and holding at -80°C for 3 minutes. [2] Heating from -80°C to 100°C at a heating rate of 10°C / min. [3] Holding 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] The sample was held 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 was -58°C or lower. B: The glass transition temperature was greater than -58°C and less than -57°C. C: The glass transition temperature was greater than -57°C and less than -56°C. D: The glass transition temperature was greater than -56°C and less than -55°C. E: The glass transition temperature was greater than -55°C and less than -54°C. F: The glass transition temperature was greater than -54°C or the crystallinity was so high that measurement was not possible.

[0091] (Handling Ease) 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 in an environment at 15°C for 10 days, after which the state of the polycarbonate polyols at 15°C after standing was 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 allowed to stand under the following conditions 1 to 4. The state of the polycarbonate polyols after standing was confirmed. The state was confirmed visually at each temperature condition. 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: Allowed to stand at 5°C for 10 days 2: Allowed to stand at 5°C for 3 months 3: Allowed to stand at 0°C for 10 days 4: Allowed to stand at 0°C for 3 months [Evaluation Criteria] A: Liquid under all of conditions 1 to 4. B: Liquid under conditions 1 to 3 and solid under condition 4. C: Liquid under conditions 1 and 2 and 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. Heat resistance was evaluated using the measured weight loss rate according to the following evaluation criteria. Heat resistance was determined to be good when the ratings were A to E. The evaluation results are shown in Tables 2 to 5. [Conditions] Measurements were performed using a STA7200RV manufactured by Hitachi High-Tech Science Corporation, following the procedure of steps [1] to [4] below. The weight loss rate when heated in air at 240°C for 60 minutes was calculated from the measurement result 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] The temperature was maintained at 240°C for 60 minutes or more. [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 23% by mass. C: The weight loss rate is greater than 23% by mass and less than 25% by mass. D: The weight loss rate is greater than 25% by mass and less than 26% by mass. E: The weight loss rate is greater than 26% by mass and less than 27% by mass. F: The weight loss rate is greater than 27% by mass.

[0094]

[0095]

[0096]

[0097]

[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 carried out at 40 to 50°C for 12 hours to obtain the polyurethanes (polyurethane-containing compositions) of Examples 18 and 19. 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 the value shown in Table 6. The urethane group concentration in the table was calculated from the blend amounts of polycarbonate polyol (active hydrogen group-containing compound) and polyisocyanate (isocyanate group-containing compound).

[0099] <Evaluation 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 x 5 mm x 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] 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 30 mm in diameter and 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) in which the sample was heated at 150 ° C. for 2000 hours, and a durability test (B) in which the sample was heated at 85 ° C. / 85% RH. DMA measurement and Shore A hardness measurement were then performed in the same manner as in the initial evaluation, and the storage modulus (E'), tan δ peak temperature, and Shore A hardness at -40 ° C were determined. Next, 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 used to calculate the rate of change in storage modulus (E'), the amount of change in tan δ peak temperature, and the rate of change in Shore A hardness. In addition, the weight change rate was calculated from the weight before and after the durability test using the same measurement sample (Φ30 mm × 13 m (height)) as in the Shore A hardness evaluation. The results are shown in Table 6.

[0102]

[0103] Details of the polyisocyanates, catalysts, and additives listed in Table 6 are as follows. [Polyisocyanates] Polyisocyanate 1: Isocyanurate-modified hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade 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. [Catalysts] DOTDL: Dioctyltin dilaurate (manufactured by Kishida Chemical Co., Ltd.) U-600: Bismuth tris(2-ethylhexanoate) (manufactured by Nitto Kasei Co., Ltd., trade 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, trade name of BASF), Tinuvin 770 (bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, trade name of BASF), and Adekastab 1500 (tetra-C12-15 alkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite), trade name of ADEKA Corporation) (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 of BASF), and Tinuvin a mixture of 123 (bis[2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl] decanedioate, product name: BASF) and Adekastab 2013 (alkyl allyl phosphite, product name: ADEKA Corporation) (mass ratio: 1:1:1);

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

[0105] The polyurethanes obtained in Examples 18 and 19 were confirmed in initial evaluation to have excellent low-temperature flexibility and sufficiently high hardness. 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

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 in which the content of 3-methyl-1,5-pentanediol in the polyol is 2 to 44 mol % (excluding those containing 0.05 to 25 wt % of silicon atoms).

2. 2. The polycarbonate polyol of claim 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.

3. The polycarbonate polyol of claim 2, wherein the first linear glycol comprises 1,6-hexanediol.

4. The polycarbonate polyol according to claim 2, 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.

5. The polycarbonate polyol according to claim 2, wherein the content of the first linear glycol in the polyol is 1 to 88 mol %.

6. The polycarbonate polyol according to claim 2, wherein the content of the second linear glycol in the polyol is 10 to 97 mol %.

7. The polycarbonate polyol according to claim 2, 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.

8. 2. The polycarbonate polyol according to claim 1, 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.

9. The polycarbonate polyol according to claim 1, wherein the content of glycols having 6 or more carbon atoms in the polyol is 90 mol % or more.

10. 2. The polycarbonate polyol according to claim 1, wherein the content of glycols having 6 to 12 carbon atoms in the polyol is 90 mol % or more.

11. The polycarbonate polyol according to claim 1, having a hydroxyl value of 30 to 180 mgKOH / g.

12. A polyurethane resin-forming composition comprising the polycarbonate polyol according to any one of claims 1 to 11 and a polyisocyanate.

13. The polyurethane resin-forming composition of claim 12, wherein the polyisocyanate comprises a non-aromatic polyisocyanate.

14. The polyurethane resin-forming composition according to claim 13, wherein the non-aromatic polyisocyanate comprises an isocyanurate-modified aliphatic polyisocyanate.

15. The polyurethane resin-forming composition according to claim 14, wherein the content of the isocyanurate-modified product is 60 to 100% by mass based on the total mass of the polyisocyanate.

16. A polyurethane resin formed from the polyurethane resin-forming composition according to claim 12.

17. A potting material comprising the polyurethane resin-forming composition according to claim 12.

18. A sealing body comprising a sealing portion formed from the potting material of claim 17.