JP7108756B1 - Polyurethane resin composition - Google Patents

Abstract

A polyurethane resin composition having excellent moist heat resistance is provided. A polyurethane resin composition according to an embodiment comprises a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B), wherein the hydroxyl group-containing compound (A) comprises a polybutadiene polyol (A1) and an alkylene oxide unit. and a butylene oxide-based polyol (A2) in which 50 mol % or more are butylene oxide units. The butylene oxide-based polyol (A2) has a number average molecular weight of 400 or more and 3,000 or less. [Selection figure] None

Description

Embodiments of the present invention relate to polyurethane resin compositions.

Conventionally, for example, electronic circuit boards and electronic components are sealed using a polyurethane resin composition in order to protect them from external factors, and polybutadiene polyol can be used as the polyol of the polyurethane resin composition. Are known.

For example, Patent Document 1 discloses a polyurethane resin composition containing a hydroxyl group-containing compound, an isocyanate group-containing compound, a metal hydroxide and a plasticizer, wherein the hydroxyl group-containing compound contains polybutadiene polyol and castor oil-based polyol, A polyurethane resin composition is disclosed wherein the metal hydroxide is aluminum hydroxide and/or magnesium hydroxide.

Japanese Patent Application Laid-Open No. 2016-20439

In electrical and electronic parts, as they are used for a long time under moist heat, along with the extension of their life, excellent moist heat resistance is required. For example, polyurethane resin compositions used as sealants for electrical insulation are required. Further improvement in wet heat resistance is desired.

An object of an embodiment of the present invention is to provide a polyurethane resin composition having excellent resistance to moist heat.

The present invention includes embodiments shown below.
[1] A polyurethane resin composition containing a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B), wherein the hydroxyl group-containing compound (A) is a polybutadiene polyol (A1) and 50 mol% of alkylene oxide units A polyurethane resin composition comprising a butylene oxide-based polyol (A2) in which the above is a butylene oxide unit, and wherein the butylene oxide-based polyol (A2) has a number average molecular weight of 400 or more and 3,000 or less.
[2] The polyurethane resin composition according to [1], wherein the content of the butylene oxide-based polyol (A2) in 100% by mass of the hydroxyl group-containing compound (A) is 10% by mass or more and 80% by mass or less.
[3] The butylene oxide-based polyol (A2) has a number average molecular weight of 600 or more and 1600 or less, and the content of the butylene oxide-based polyol (A2) in 100% by mass of the hydroxyl group-containing compound (A) is 20% by mass or more. The polyurethane resin composition according to [1] or [2], which is 60% by mass or less.
[4] The polyurethane resin composition according to any one of [1] to [3], wherein the isocyanate group-containing compound (B) contains an isocyanurate modified product.
[5] Any one of [1] to [4], which is a two-pack type containing a first liquid containing the hydroxyl group-containing compound (A) and a second liquid containing the isocyanate group-containing compound (B). 2. The polyurethane resin composition according to item 1.
[6] The polyurethane resin composition according to any one of [1] to [5], which is used as an electrical insulating sealant.

According to the embodiment of the present invention, it is possible to provide a polyurethane resin composition having excellent moist heat resistance.

The polyurethane resin composition according to this embodiment contains a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B).

[Hydroxyl group-containing compound (A)]
As the hydroxyl group-containing compound (A), a polyol compound having two or more hydroxyl groups in one molecule can be used. In the present embodiment, the hydroxyl group-containing compound (A) is a polybutadiene polyol (A1) and a butylene oxide and a polyol (A2).

The polybutadiene polyol (A1) is not particularly limited, and preferably has a 1,4-bonded type, 1,2-bonded type or a mixture of these polybutadiene structures and at least two hydroxyl groups in the molecule. More preferably, both ends of the polybutadiene structure have hydroxyl groups. The polybutadiene polyol (A1) may be a hydrogenated polybutadiene polyol in which some or all of its unsaturated double bonds are hydrogenated, or a combination of non-hydrogenated and hydrogenated polybutadiene polyols. Moreover, two or more polybutadiene polyols having different molecular weights and functional group numbers may be used in combination.

The molecular weight of the polybutadiene polyol (A1) is not particularly limited. good.

The number of functional groups of polybutadiene polyol (A1) is not particularly limited, and may be, for example, 2.0 to 4.0 or 2.0 to 2.5.

The hydroxyl value of the polybutadiene polyol (A1) is not particularly limited, and may be, for example, 10 to 200 mgKOH/g, 15 to 150 mgKOH/g, 20 to 120 mgKOH/g, 25 to 100 mgKOH/g, or 40 to 90 mgKOH. /g.

As used herein, the number average molecular weight (Mn) of polybutadiene polyol (A1) is a value measured by GPC (gel permeation chromatography) and calculated using a standard polystyrene calibration curve. GPC conditions are, for example, column: "TSKgel GMHHR-H" manufactured by Tosoh Corporation, solvent: THF, flow rate: 0.6 mL/min, measurement temperature: 40°C. The hydroxyl value of the polybutadiene polyol (A1) is a value measured according to A method of JIS K1557-1:2007, and potassium hydroxide ( KOH) in mg. The number of functional groups of polybutadiene polyol (A1) is a value calculated by the following formula.
Number of functional groups = {(hydroxyl value) x (Mn)}/(56.1 x 1000)

The content of the polybutadiene polyol (A1) is not particularly limited, but is preferably 20 to 90% by mass, more preferably 40 to 80% by mass, based on 100% by mass of the hydroxyl group-containing compound (A). It is preferably 50 to 80% by mass.

The butylene oxide-based polyol (A2) is a polyol in which 50 mol % or more of the alkylene oxide units are butylene oxide units. More specifically, the butylene oxide-based polyol (A2) is a polyalkylene glycol in which 50 mol% or more of the total alkylene oxide used to form the polyol is butylene oxide, and is a broadly defined polybutylene glycol. . By using the butylene oxide polyol (A2) together with the polybutadiene polyol (A1) as the hydroxyl group-containing compound (A), the moist heat resistance of the polyurethane resin composition can be improved. In addition, compared to the case of using a castor oil-based polyol, it is possible to lower the mixed viscosity during the production of the polyurethane resin composition, thereby improving the workability.

In the butylene oxide-based polyol (A2), the amount of butylene oxide units relative to all alkylene oxide units is preferably 60 mol% or more, more preferably 60 mol% or more, from the viewpoint of wet heat resistance and compatibility with the polybutadiene polyol (A1). It may be 70 mol % or more, may be 80 mol % or more, may be 90 mol % or more, or may be 100 mol %. When having alkylene oxide units other than butylene oxide units, the other alkylene oxide units are not particularly limited, and examples include ethylene oxide units and/or propylene oxide units.

In a preferred embodiment, the butylene oxide-based polyol (A2) may be a polybutylene glycol composed of 100 mol % alkylene oxide units of butylene oxide units.

In this embodiment, a butylene oxide polyol (A2) having a number average molecular weight (Mn) of 400 to 3000 is used. When the butylene oxide polyol (A2) has a number average molecular weight of 400 or more, compatibility with the polybutadiene polyol (A1) can be improved. Moreover, when it is 3000 or less, the curability of the polyurethane resin composition can be improved. The butylene oxide polyol (A2) preferably has a number average molecular weight of 600 or more, more preferably 800 or more. The number average molecular weight is preferably 2000 or less, more preferably 1600 or less, and may be 1300 or less.

The hydroxyl value of the butylene oxide polyol (A2) is not particularly limited, and may be, for example, 37 to 500 mgKOH/g, 50 to 300 mgKOH/g, or 60 to 200 mgKOH/g.

In this specification, the number average molecular weight (Mn) of the butylene oxide-based polyol (A2) is a value converted from the hydroxyl value and the number of functional groups according to the following formula.
Number average molecular weight = 56.1 × 1000 × number of functional groups / hydroxyl value The hydroxyl value of the butylene oxide polyol (A2) is a value (mgKOH/g) measured according to A method of JIS K1557-1:2007. . The number of functional groups of the butylene oxide-based polyol (A2) is obtained from the number of active hydrogen atoms in the active hydrogen atom-containing compound as an initiator as described below.

The structure of the butylene oxide-based polyol (A2) is not particularly limited. For example, it has a structure obtained by addition polymerization of an alkylene oxide containing butylene oxide to a compound having 2 to 8 active hydrogen atoms as an initiator. may As the butylene oxide, 1,2-butylene oxide and/or 2,3-butylene oxide are used, preferably 1,2-butylene oxide.

If a compound (diol) having two active hydrogen atoms such as ethylene glycol or propylene glycol is used as the initiator, a bifunctional butylene oxide polyol (A2) can be obtained. If a compound (triol) having three active hydrogen atoms such as glycerin or trimethylolpropane is used as the initiator, a trifunctional butylene oxide polyol (A2) can be obtained. Since it is believed that tri-functionality cures faster than di-functionality, a tri-functional butylene oxide polyol (A2) may be used when faster curing is desired. The number of functional groups of the butylene oxide-based polyol (A2) is not particularly limited, and may be 2-8 or 2-4. Preferably, the butylene oxide-based polyol (A2) is bifunctional or trifunctional, and a combination of bifunctional and trifunctional may be used.

In the case where butylene oxide is copolymerized with other alkylene oxide as the form of addition polymerization, random copolymerization or block copolymerization may be used. In one embodiment, a terminal ethylene oxide-added polybutylene glycol having a structure in which butylene oxide is added to an initiator and then ethylene oxide is added to the end of the polybutylene oxide chain may be used. Curability can be enhanced by adding ethylene oxide to the terminal.

As the butylene oxide-based polyol (A2), any one of those having the above structure may be used, or two or more of those having different number average molecular weights, structures, etc. may be used in combination.

Although the content of the butylene oxide-based polyol (A2) is not particularly limited, it is preferably 10 to 80% by mass with respect to 100% by mass of the hydroxyl group-containing compound (A). When the content of the butylene oxide-based polyol (A2) is 10% by mass or more, the mixed viscosity during production of the polyurethane resin composition can be lowered. Further, when the content is 80% by mass or less, the curability can be improved. The content of the butylene oxide-based polyol (A2) is more preferably 20 to 60% by mass, still more preferably 20 to 50% by mass.

The mass ratio of the polybutadiene polyol (A1) and the butylene oxide polyol (A2) is not particularly limited, but (A2)/(A1) is preferably 0.1 to 3.5, more preferably 0.2. ~1.0.

In the present embodiment, the hydroxyl group-containing compound (A) may be composed only of the polybutadiene polyol (A1) and the butylene oxide polyol (A2), but may also contain other hydroxyl group-containing compounds. Although the total amount (A1+A2) of the polybutadiene polyol (A1) and the butylene oxide polyol (A2) relative to 100% by mass of the hydroxyl group-containing compound (A) is not particularly limited, it is preferably 70% by mass or more, more preferably 80% by mass. It is at least 90% by mass, more preferably at least 90% by mass, and may be 100% by mass.

Various polyols are used as the other hydroxyl group-containing compound, and there is no particular limitation. Examples thereof include castor oil, castor oil fatty acids, hydrogenated castor oils obtained by hydrogenating these, and castor oil-based polyols produced using hydrogenated castor oil fatty acids. Further, other polyester polyols, polyether polyols, polycarbonate polyols, dimer acid polyols, polycaprolactone polyols, acrylic polyols, polyisoprene polyols, and the like are included. Furthermore, low-molecular-weight polyols that are commonly used as cross-linking agents may be used. Specifically, N,N-bis(2-hydroxypropyl)aniline, hydroquinone-bis(β-hydroxyethyl)ether, resorcinol-bis(β -hydroxyethyl) ether, and aliphatic alcohols such as ethylene glycol, 1,4-butanediol, octanediol, trimethylolpropane, and triisopropanolamine.

[Isocyanate group-containing compound (B)]
Various polyisocyanate compounds having two or more isocyanate groups in one molecule can be used as the isocyanate group-containing compound (B). The isocyanate group-containing compound (B) includes, for example, an aliphatic polyisocyanate compound (B1), an alicyclic polyisocyanate compound (B2), an aromatic polyisocyanate compound (B3), and modified and polynuclear compounds thereof. Any one of them may be used, or two or more may be used in combination.

Examples of the aliphatic polyisocyanate compound (B1) include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate and the like.

Examples of the alicyclic polyisocyanate compound (B2) include isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3 -Bis(isocyanatomethyl)cyclohexane and the like.

Examples of the aromatic polyisocyanate compound (B3) include tolylene diisocyanate (TDI, such as 2,4-TDI, 2,6-TDI), diphenylmethane diisocyanate (MDI, such as 2,2'-MDI, 2,4' -MDI, 4,4'-MDI), 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate (XDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, etc. mentioned.

Modified products of these polyisocyanate compounds (B1) to (B3) include, for example, isocyanurate modified products, allophanate modified products, buret modified products, adduct modified products and carbodiimide modified products.

In one embodiment, the isocyanate group-containing compound (B) preferably contains an isocyanurate modified product. By using the modified isocyanurate, it has excellent miscibility with the hydroxyl group-containing compound (A), and can improve uniformity of hardness of the cured polyurethane resin composition. Examples of the isocyanurate modified product include an isocyanurate modified product of the aliphatic polyisocyanate compound (B1), an isocyanurate modified product of the alicyclic polyisocyanate compound (B2), and an isocyanurate modified product of the aromatic polyisocyanate compound (B3). mentioned. Preferred is the isocyanurate modified form of the aliphatic polyisocyanate compound (B1), and more preferred is HDI isocyanurate.

In another embodiment, the isocyanate group-containing compound (B) preferably contains HDI. As the isocyanate group-containing compound (B), HDI and the modified isocyanurate may be used in combination, or HDI and HDI isocyanurate may be used in combination.

In yet another embodiment, the isocyanate group-containing compound (B) may contain MDI. MDI may be monomeric MDI or polymeric MDI (crude MDI). As the isocyanate group-containing compound (B), MDI may be used in combination with the above HDI and/or modified isocyanurate (preferably HDI isocyanurate).

The content of the isocyanate group-containing compound (B) in the polyurethane resin composition is not particularly limited. parts, 10 to 40 parts by mass, or 15 to 30 parts by mass.

The ratio of the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B) is not particularly limited. The ratio NCO/OH (index) may be from 0.6 to 1.5, from 0.7 to 1.3, or from 0.8 to 1.2.

[Other ingredients]
In addition to the components described above, the polyurethane resin composition according to the present embodiment may optionally contain, for example, a catalyst, an antioxidant, a foam stabilizer, a diluent, a flame retardant, an ultraviolet absorber, a colorant, Various additives such as fillers and plasticizers can be added as long as the purpose of the present embodiment is not impaired.

Examples of catalysts that can be used include metal catalysts such as organotin catalysts, organolead catalysts and organobismuth catalysts, and various urethane polymerization catalysts such as amine catalysts. The content of the catalyst is not particularly limited, and may be, for example, 0.0001 to 0.1% by mass or 0.001 to 0.01% by mass with respect to 100% by mass of the polyurethane resin composition.

[Polyurethane resin composition]
The polyurethane resin composition according to the present embodiment is configured as a two-component polyurethane resin composition containing a first liquid containing a hydroxyl group-containing compound (A) and a second liquid containing an isocyanate group-containing compound (B). may Such a two-pack type polyurethane resin composition may further comprise a third liquid containing the other components as well as the first and second liquids.

The two-component polyurethane resin composition can be produced by preparing a first liquid and a second liquid, respectively, that is, the first liquid and the second liquid may be filled in separate containers. . The first liquid and the second liquid filled in separate containers are mixed at the time of use, whereby the hydroxyl group-containing compound (A) and the isocyanate group-containing compound (B) react to form a polyurethane resin, which is cured. good too. At that time, it may be cured by heating. The polyurethane resin composition according to this embodiment may be obtained by mixing the first liquid and the second liquid, may be in a liquid state before curing, or may be in a cured state.

The first liquid may be composed only of the hydroxyl group-containing compound (A), and in addition to the hydroxyl group-containing compound (A), if necessary, for example, a catalyst, an antioxidant, a foam stabilizer, a diluent , flame retardants, ultraviolet absorbers, colorants, fillers, plasticizers, and other additives. Preferably, the first liquid contains a hydroxyl group-containing compound (A) and a catalyst.

The second liquid may be composed only of the isocyanate group-containing compound (B), and in addition to the isocyanate group-containing compound (B), if necessary, for example, an antioxidant, a foam stabilizer, a diluent , flame retardants, ultraviolet absorbers, colorants, fillers, plasticizers, and other additives.

[Applications of Polyurethane Resin Composition]
The use of the polyurethane resin composition according to the present embodiment is not particularly limited, but it is preferably used as an electrical insulating sealant in electrical and electronic parts. Examples of electrical and electronic components include, but are not limited to, transformers such as transformer coils, choke coils and reactor coils, equipment control boards, sensors, and wireless communication components.

Electrical and electronic components resin-sealed using the polyurethane resin composition according to the present embodiment include, for example, electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, solar panels, power tools, and automobiles. , can be used for motorcycles, etc.

Hereinafter, the polyurethane resin composition will be described in detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

Details of each component used in Examples and Comparative Examples are shown below.

[Hydroxyl group-containing compound (A)]
· Polybutadiene polyol 1: number average molecular weight 2800, hydroxyl value 47 mgKOH / g, functional group number 2.3, product name: Poly bd R-45HTLO, manufactured by Clay Valley · Polybutadiene polyol 2: number average molecular weight 1600, hydroxyl value 80 mgKOH / g , functional group number 2.3, prepared by the following method

150 parts by mass of 1,3-butadiene, 105 parts by mass of an azeotropic mixture containing 88% by mass of isopropanol and 12% by mass of water, and 30% by mass of a 60% aqueous hydrogen peroxide solution were placed in a stirred reactor in which the inside of the system was replaced with nitrogen. prepared the department. The contents of the reactor were heated to 120° C. with continuous stirring and maintained at 120° C. to 130° C. with stirring for 2 hours to carry out the polymerization reaction. After the predetermined time period is complete, the reactor contents are cooled, the reaction product is removed from the reactor, unreacted monomer is removed from the reaction product, and the product is washed with water to remove residual isopropanol and unreacted hydrogen peroxide. removed. This product was vacuum dried to obtain a polybutadiene polyol having a viscosity of 5000 mPa·s at 25°C.

BO-based polyol 1: Polybutylene glycol obtained by addition polymerization of butylene oxide using propylene glycol as an initiator according to Synthesis Example 1 below (number average molecular weight: 3000, number of functional groups: 2, butylene oxide units in all alkylene oxide units amount of 100 mol%)

Synthesis Example 1: 2.53 parts by mass of propylene glycol, 0.55 parts by mass of 48% KOH and 10.8 parts by mass of 1,2-butylene oxide (BO) were charged into a stainless steel autoclave, and after replacing with nitrogen, the pressure in the autoclave was reduced. and heated. After the BO introduction reaction was carried out at 120±5° C. and the maximum pressure of 0.2 MPa, the BO aging reaction was carried out at 120±5° C. for 240 minutes. After cooling to 80°C, the pressure was reduced to 10 mmHg or less at 90 to 110°C. After that, 86.67 parts by mass of BO was added, and after performing BO introduction reaction at 120±5° C. and maximum pressure of 0.4 MPa, BO aging reaction was performed at 120±5° C. for 360 minutes. After cooling, the pressure was reduced to 20 mmHg (2.7 kPa) at 100±5° C., followed by purification and filtration to obtain bifunctional polybutylene glycol.

BO-based polyol 2: In Synthesis Example 1 above, the amount of BO added after the BO aging reaction in the first stage was set to 40 parts by mass, and the others were the same as in Synthesis Example 1, butylene oxide was added using propylene glycol as an initiator. Polybutylene glycol obtained by addition polymerization (number average molecular weight: 1600, number of functional groups: 2, amount of butylene oxide units in all alkylene oxide units: 100 mol%)

BO-based polyol 3: In Synthesis Example 1 above, the amount of BO added after the BO ripening reaction in the first stage was set to 13.3 parts by mass, and the other methods were the same as in Synthesis Example 1, butylene glycol was used as an initiator. Polybutylene glycol obtained by addition polymerization of oxide (number average molecular weight 800, number of functional groups 2, amount of butylene oxide units in all alkylene oxide units 100 mol%)

BO-based polyol 4: Polybutylene glycol obtained by addition polymerization of butylene oxide using propylene glycol as an initiator according to Synthesis Example 2 below (number average molecular weight: 400, number of functional groups: 2, butylene oxide units among all alkylene oxide units amount of 100 mol%)

Synthesis Example 2: 19 parts by mass of propylene glycol, 0.83 parts by mass of 48% KOH and 81 parts by mass of 1,2-butylene oxide (BO) were charged into a stainless steel autoclave and replaced with nitrogen. did. After the BO introduction reaction was carried out at 120±5° C. and the maximum pressure of 0.2 MPa, the BO aging reaction was carried out at 120±5° C. for 240 minutes. After cooling to remove BO, the pressure was reduced to 20 mmHg (2.7 kPa) at 100±5° C., followed by purification and filtration to obtain bifunctional polybutylene glycol.

BO-based polyol 5: According to Synthesis Example 3 below, butylene oxide was addition-polymerized using propylene glycol as an initiator, and ethylene oxide was added to the end of the polybutylene glycol with EO (number average molecular weight: 1250, functional radix 2, amount of butylene oxide units in all alkylene oxide units: 57 mol%, amount of ethylene oxide units: 43 mol%)

Synthesis Example 3: 6.08 parts by mass of propylene glycol, 0.55 parts by mass of 48% KOH, and 25.9 parts by mass of 1,2-butylene oxide (BO) were charged into a stainless steel autoclave, and after purging with nitrogen, the pressure in the autoclave was reduced. and heated. After the BO introduction reaction was carried out at 120±5° C. and the maximum pressure of 0.2 MPa, the BO aging reaction was carried out at 120±5° C. for 240 minutes. Then, after cooling to 80°C, it was withdrawn, and the pressure was reduced to 10 mmHg or less at 90 to 110°C. After that, 38.0 parts by mass of BO was added, and after performing BO introduction reaction at 120±5° C. and maximum pressure of 0.4 MPa, BO aging reaction was performed at 120±5° C. for 360 minutes. After that, 30.0 parts by mass of ethylene oxide (EO) was added, and an EO introduction reaction was performed at 120 ± 5°C and a maximum pressure of 0.4 MPa, and then an EO aging reaction was performed at 120 ± 5°C for 360 minutes. . After cooling without EO, the pressure was reduced to 20 mmHg (2.7 kPa) at 100±5° C., followed by purification and filtration to obtain EO-terminated polybutylene glycol.

BO-based polyol 6: Polybutylene glycol obtained by addition polymerization of butylene oxide using glycerin as an initiator according to Synthesis Example 4 below (number average molecular weight of 1100, number of functional groups of 3, number of butylene oxide units in all alkylene oxide units amount 100 mol%)

Synthesis Example 4: To 8.37 parts by mass of glycerin, 0.5 parts by mass of 48% KOH and 28.1 parts by mass of 1,2-butylene oxide (BO) were charged into a stainless steel autoclave, and after purging with nitrogen, the pressure in the autoclave was reduced. , raised the temperature. After the BO introduction reaction was carried out at 120±5° C. and the maximum pressure of 0.2 MPa, the BO aging reaction was carried out at 120±5° C. for 240 minutes. After cooling to 80°C, the pressure was reduced to 10 mmHg or less at 90 to 110°C. After that, 63.62 parts by mass of BO was added, and after performing BO introduction reaction at 120±5° C. and maximum pressure of 0.4 MPa, BO aging reaction was performed at 120±5° C. for 360 minutes. After cooling, the pressure was reduced to 20 mmHg (2.7 kPa) at 100±5° C., followed by purification and filtration to obtain trifunctional polybutylene glycol.

- BO-based polyol 7: According to Synthesis Example 5 below, butylene oxide is addition-polymerized using glycerin as an initiator, and ethylene oxide is added to the end of the polybutylene glycol (number average molecular weight: 1,120, number of functional groups 3, the amount of butylene oxide units in all alkylene oxide units is 84 mol%, and the amount of ethylene oxide units is 16 mol%)

Synthesis Example 5: In Synthesis Example 4 above, 55.24 parts by mass of BO was added in the second-stage BO aging reaction, 10.2 parts by mass of ethylene oxide (EO) was added, and the temperature was adjusted to 120°C ± 5°C and the maximum pressure of 0. After performing the EO introduction reaction at 4 MPa, the EO aging reaction was performed at 120±5° C. for 360 minutes. After cooling without EO, the pressure was reduced to 20 mmHg (2.7 kPa) at 100±5° C., followed by purification and filtration to obtain trifunctional EO-terminated polybutylene glycol.

・ PO polyol 1: number average molecular weight 700, functional group 2 polypropylene glycol, product name: Hiflex D-700, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ・ PO polyol 2: number average molecular weight 1000, functional group 2 Polypropylene glycol, product name: Hiflex D-1000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. PO-based polyol 3: polyoxyethylene polyoxypropylene glycol with a number average molecular weight of 1,300 and a number of functional groups of 2, product name: Epan 410, No. Ichi Kogyo Seiyaku Co., Ltd. PO polyol 4: number average molecular weight 1000, functional group 3 polypropylene glycol, product name: X-2116, Daiichi Kogyo Seiyaku Co., Ltd. PO polyol 5: number average molecular weight 3000 , Polypropylene glycol with a functional number of 3, Product name: Hiflex G-3000, Daiichi Kogyo Seiyaku Co., Ltd. Castor oil-based polyol: Number average molecular weight 938, Functional group number 2.7, Product name: Castor oil D, Ito oil ( Co., Ltd.

[catalyst]
・Catalyst: dioctyl tin, product name: Neostan U-810, manufactured by Nitto Kasei Co., Ltd.

[Isocyanate group-containing compound (B)]
・Polyisocyanate 1: HDI isocyanurate, product name: Duranate TPA-100, manufactured by Asahi Kasei Co., Ltd. ・Polyisocyanate 2: HDI, product name: Duranate D-201, manufactured by Asahi Kasei Co., Ltd. ・Polyisocyanate 3: Crude MDI, Product name: Luplanate M5S, manufactured by BASF INOAC Polyurethane Co., Ltd.

[Examples 1 to 10 and Comparative Examples 1 to 6]
Polyurethane resin compositions of Examples and Comparative Examples were prepared according to the formulations (parts by mass) shown in Tables 1 and 2 below. For the preparation, a predetermined amount of the first liquid shown in Tables 1 and 2 was weighed, and stirred and mixed while being melted by heating appropriately. After mixing, the temperature was adjusted to 25°C. Subsequently, the second liquid (isocyanate group-containing compound (B)) adjusted to 25° C. was added to the mixture as shown in Tables 1 and 2, and the mixture was stirred and mixed to degas.

Compatibility, curability, durability, volume resistivity and migration properties were measured and evaluated for each example and each comparative example. The measurement and evaluation methods are as follows.

[Compatibility]
After mixing polybutadiene polyol, which is a hydroxyl group-containing compound, with BO-based polyol, PO-based polyol or castor oil-based polyol, the mixture was allowed to stand at room temperature for 7 days, and the state of the liquid after standing was evaluated according to the following criteria.
A: Transparent B: Turbidity C: Separation

[Curability]
The polyurethane resin composition after defoaming was poured into a container of 5 cm long×5 cm wide×3 cm high, left in a curing oven at 80° C. for 1 hour, and then the hardness of the resin was measured. The hardness was measured with a type A durometer conforming to JIS K6253-3 and a type C hardness tester conforming to JIS K7312, and evaluated according to the following criteria. The curability is an evaluation of whether or not the composition cures quickly.
A: type A durometer hardness of 0 or more,
B: Type A durometer hardness is less than 0 (cannot be measured with type A durometer) and type C hardness is 0 or more C: No curing or liquid

[durability]
The defoamed polyurethane resin composition was poured into a mold of 5 cm long×5 cm wide×1 cm high and cured in a curing furnace at 80° C. for 48 hours to prepare resin pieces. The resin piece was treated in a high temperature and high humidity bath at a temperature of 121 ° C., a humidity of 100%, and a humidity of 2 atm, and after 500 hours and 1000 hours, the hardness was measured with a type A durometer in accordance with JIS K6253-3. The change from 0.01% was confirmed and evaluated according to the following criteria.
A: Less than 10% change in hardness after 1000 hours B: Less than 10% change in hardness after 500 hours and 10% or more change in hardness after 1000 hours C: 10% change in hardness after 500 hours that's all

[Volume resistivity]
A resin piece having the same durability as described above was prepared, and the resin piece was treated in a high-temperature and high-humidity bath at a temperature of 121 ° C., a humidity of 100%, and 2 atm. The specific resistance was measured according to JIS K6911 (measured voltage: 500 V) and evaluated according to the following criteria.
A: Volume resistivity after 1000 hours is 10 ⁹ Ω·cm or more B: Volume resistivity is less than 10 ⁹ Ω·cm after 1000 hours and volume resistivity is 10 ⁹ Ω·cm or more after 750 hours C: The volume resistivity after 750 hours is less than 10 ⁹ Ω·cm and the volume resistivity after 500 hours is 10 ⁹ Ω·cm or more.

[Migration characteristics]
A JIS type 2 comb-shaped electrode substrate was placed on a glass petri dish, and an anode and a cathode were wired. The defoamed polyurethane resin composition was poured onto the mold and cured in a curing oven at 80° C. for 48 hours to prepare a test piece. The test piece was subjected to a migration test by applying a voltage of 100 V in a moist heat bath at a temperature of 85° C. and a humidity of 85%, and whether or not the current was applied within 1000 hours was evaluated according to the following criteria. As the amount of water around the electrode increases, copper ions are eluted from the anode, migrate to the cathode, and deposit on the cathode side. If the deposit grows, it causes insulation failure, and finally short-circuits between wiring patterns. This is a test of whether or not such a short circuit occurs.
A: Not energized C: Energized

The results are shown in Tables 1 and 2. Comparative Examples 1 to 5 using PO-based polyols 1 to 5 as polyols used in combination with polybutadiene polyol were excellent in durability (hardness change) after wet heat treatment, but the volume resistivity after wet heat treatment was excellent. The deterioration was large, the migration property was poor, and the wet heat resistance was poor.

In Comparative Example 6, in which a castor oil-based polyol was used as the polyol used in combination with the polybutadiene polyol, the migration properties after the wet heat treatment were excellent, but the durability (hardness change) after the wet heat treatment was poor, and the volume resistivity was poor. also showed a downward trend. Moreover, when a castor oil-based polyol was used, curability was also inferior.

On the other hand, Examples 1 to 10 in which polybutadiene polyol and BO-based polyol were used in combination were excellent in durability (hardness change), volume resistivity and migration properties after wet heat treatment, and were superior to Comparative Examples 1 to 6. It was excellent in heat and humidity resistance.

It should be noted that the various numerical ranges described in the specification can be arbitrarily combined with their upper and lower limits, and all combinations thereof are described in this specification as preferred numerical ranges. Further, the description of the numerical range "X to Y" means X or more and Y or less.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments, their omissions, replacements, modifications, etc., are included in the scope and spirit of the invention, as well as in the scope of the invention described in the claims and equivalents thereof.

Claims (5)

A polyurethane resin composition containing a hydroxyl group-containing compound (A) and an isocyanate group-containing compound (B) , wherein a first liquid containing the hydroxyl group-containing compound (A) and a second liquid containing the isocyanate group-containing compound (B) A two-liquid type containing a liquid and
The hydroxyl group-containing compound (A) contains a polybutadiene polyol (A1) and a bifunctional butylene oxide polyol (A2) in which 50 mol% or more of the alkylene oxide units are butylene oxide units,
The butylene oxide-based polyol (A2) has a number average molecular weight of 400 or more and 3000 or less ,
A polyurethane resin composition , wherein the molar ratio NCO/OH between the isocyanate groups of the isocyanate group-containing compound (B) and the hydroxyl groups of the hydroxyl group-containing compound (A) is 0.6 to 1.5 . 2. The polyurethane resin composition according to claim 1, wherein the content of said butylene oxide polyol (A2) in 100% by mass of said hydroxyl group-containing compound (A) is 10% by mass or more and 80% by mass or less. The number average molecular weight of the butylene oxide-based polyol (A2) is 600 or more and 1600 or less, and the content of the butylene oxide-based polyol (A2) in 100% by mass of the hydroxyl group-containing compound (A) is 20% by mass or more and 60% by mass. The polyurethane resin composition according to claim 1 or 2, wherein: The polyurethane resin composition according to any one of claims 1 to 3, wherein the isocyanate group-containing compound (B) contains an isocyanurate modified product. The polyurethane resin composition according to any one of claims 1 to 4 , which is used as an electrical insulating sealant.