JP6012821B1 - Polyurethane resin composition, sealing material and electric / electronic component - Google Patents

Abstract

Disclosed is a polyurethane resin composition having excellent workability, a cured polyurethane resin can exhibit flexibility for a long period of time, and can exhibit excellent heat resistance and moisture resistance. A polyurethane resin composition comprising a polyurethane resin obtained by reacting an isocyanate group-containing compound and a hydroxyl group-containing compound, an inorganic filler, and a plasticizer, wherein the hydroxyl group-containing compound contains a hydride of polybutadiene polyol. The polybutadiene polyol hydride has a content of polybutadiene units having 1,2-vinyl groups of 7 mol% or less with respect to 100 mol% of the total amount of polybutadiene units and hydrogenated polybutadiene units, and has a number average molecular weight. Is a polyurethane resin composition, characterized in that it is 1500-2500. [Selection figure] None

Description

  The present invention relates to a polyurethane resin composition, a sealing material, and an electric / electronic component.

  In recent years, the density and integration of electric and electronic parts have been increased, and improvement of reliability is required for each part. These electric and electronic parts are sealed with a sealing material in order to impart moisture resistance, and a polyurethane resin composition is used as the sealing material.

  The polyurethane resin composition used for the encapsulant is required to have flexibility in order to protect electric and electronic parts.

  In addition, an inorganic filler is usually added to the polyurethane resin composition used for the sealing material in order to impart heat dissipation. When the polyurethane resin composition contains an inorganic filler, the viscosity becomes high, so that the polyurethane resin composition cannot be sufficiently mixed and is difficult to be uniform. When mixing of the polyurethane resin composition is insufficient, there is a problem that the polyurethane resin composition after curing is difficult to be uniform, and heat dissipation and insulation cannot be maintained over a long period of time.

  A polyurethane resin composition containing a hydrogenated castor oil-based polyol exhibiting a specific iodine value, for example, as a polyurethane resin composition that can be sufficiently mixed due to reduced viscosity and maintains heat dissipation and flexibility after curing Has been proposed (see Patent Document 1).

  However, in the polyurethane resin composition described in Patent Document 1, castor oil-based polyol is used, and when only castor oil-based polyol is used, there is a problem that moisture resistance is inferior and hydrolysis is caused in a long-term reliability test.

  Moreover, heat resistance is imparted by using an antioxidant, and the heat resistance of the polyurethane resin itself has not been studied, and there is a problem that the heat resistance of the polyurethane resin composition after curing is not sufficient.

  Therefore, the development of a polyurethane resin composition that is excellent in workability, can be cured for a long time, and can exhibit excellent heat resistance and moisture resistance is required. It has been.

Japanese Patent No. 5596921

  The present invention provides a polyurethane resin composition that is excellent in workability, the cured polyurethane resin composition can exhibit flexibility for a long period of time, and can exhibit excellent heat resistance and moisture resistance. The purpose is to do.

  As a result of extensive research, the present inventor has obtained a polyurethane resin obtained by reacting an isocyanate group-containing compound and a hydroxyl group-containing compound, and a polyurethane resin composition containing an inorganic filler and a plasticizer. The content of the polybutadiene unit having a 1,2-vinyl group with respect to 100 mol% of the total amount of the polybutadiene unit and the hydrogenated polybutadiene unit is 7 mol% or less. And if it was set as the structure whose number average molecular weight is 1500-2500, it discovered that the said objective could be achieved and came to complete this invention.

That is, this invention relates to the following polyurethane resin compositions, sealing materials, and electric / electronic parts.
1. A polyurethane resin composition comprising an isocyanate group-containing compound and a hydroxyl group-containing compound, a polyurethane resin composition containing an inorganic filler and a plasticizer,
The hydroxyl group-containing compound contains a hydride of polybutadiene polyol,
The hydride of the polybutadiene polyol has a content of polybutadiene units having 1,2-vinyl groups of 7 mol% or less with respect to a total amount of 100 mol% of polybutadiene units and hydrogenated polybutadiene units, and has a number average molecular weight of 1500. ~ 2500,
A polyurethane resin composition characterized by that.
2. Item 2. The polyurethane resin composition according to Item 1, wherein the hydroxyl group-containing compound further comprises at least one selected from a castor oil-based polyol and a hydride of castor oil-based polyol.
3. Item 3. The polyurethane resin composition according to Item 1 or 2, wherein the isocyanate group-containing compound contains an isocyanurate-modified product of hexamethylene diisocyanate.
4). Item 4. A sealing material comprising the polyurethane resin composition according to any one of Items 1 to 3.
5. Item 5. An electrical and electronic component sealed with a resin using the sealing material according to Item 4.

  The polyurethane resin composition of the present invention is excellent in workability, the cured polyurethane resin composition can exhibit flexibility for a long period of time, and can exhibit excellent heat resistance and moisture resistance. Moreover, since the sealing material of this invention also consists of the said polyurethane resin composition after hardening, it can show flexibility for a long period of time, and can show the outstanding heat resistance and moisture resistance. Furthermore, since the electrical / electronic component of the present invention is resin-sealed using the sealing material, it can exhibit high reliability even in a high-temperature and high-humidity environment.

  Hereinafter, the polyurethane resin composition, the sealing material and the electric / electronic component of the present invention will be described in detail.

  The polyurethane resin composition of the present invention contains a polyurethane resin formed by a reaction between a hydroxyl group-containing compound and an isocyanate group-containing compound.

(Isocyanate group-containing compound)
Examples of the isocyanate group-containing compound include an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, an aromatic polyisocyanate compound, an araliphatic polyisocyanate compound and the like, and these allophanate modified products and isocyanurates. A modified body can be used.

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

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

  Examples of the aromatic polyisocyanate compound include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-dibenzyl diisocyanate, 1, Examples include 5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate.

  Examples of the araliphatic polyisocyanate compound include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α, α, α, α-tetramethylxylylene diisocyanate.

  The isocyanurate-modified product of the polyisocyanate group-containing compound is preferably an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, or an isocyanurate-modified product of an aromatic polyisocyanate compound. Among them, hexamethylene diisocyanate or diphenylmethane diisocyanate is preferable. The isocyanurate-modified product is more preferable.

  Among the polyisocyanate compounds, it is more preferable to use an isocyanurate-modified product of hexamethylene diisocyanate from the viewpoint of imparting more excellent heat resistance and moisture resistance to the polyurethane resin composition of the present invention.

  The said polyisocyanate group containing compound may be used independently, and may mix and use 2 or more types.

  Commercially available products of polyisocyanate group-containing compounds include Coronate HX (trade name HDI-based isocyanurate manufactured by Tosoh Corporation), Duranate TLA-100 (trade name HDI-based isocyanurate manufactured by Asahi Kasei Chemicals Corporation), Millionate MTL (trade name MDI-based isocyanate) Manufactured by Tosoh Corporation).

  In the polyurethane resin composition of the present invention, the amount of the isocyanate group-containing compound used is preferably 1 to 30% by mass, more preferably 4 to 20% by mass, based on 100% by mass of the polyurethane resin composition.

(Hydroxyl-containing compound)
The hydroxyl group-containing compound used in the polyurethane resin composition of the present invention contains a hydride of polybutadiene polyol. In this specification, the hydride of polybutadiene polyol is a polybutadiene polyol obtained by hydrogenating a double bond in a polybutadiene polyol molecule, and hydrogen atoms are added to some double bonds in the polybutadiene polyol molecule. Includes hydrogenated products.

  The hydride of polybutadiene polyol used in the polyurethane resin composition of the present invention has a content of polybutadiene units having 1,2-vinyl groups of 7 mol% or less with respect to 100 mol% of the total amount of polybutadiene units and hydrogenated polybutadiene units. is there. When the content of the polybutadiene unit having a 1,2-vinyl group is 7 mol% or less, the polyurethane resin composition of the present invention exhibits flexibility for a long period of time, and also exhibits excellent heat resistance and moisture resistance. . In the present specification, the hydrogenated polybutadiene unit is a polybutadiene unit in which a hydrogen atom is hydrogenated to a double bond in the polybutadiene unit.

  In the present specification, the content of the polybutadiene unit having a 1,2-vinyl group with respect to 100 mol% of the total amount of the polybutadiene unit and the hydrogenated polybutadiene unit in the hydride of the polybutadiene polyol is determined by nuclear magnetic resonance spectroscopy ( NMR). That is, the intensity of the spectrum derived from the polybutadiene unit having a 1,2-vinyl group, the spectrum derived from the polybutadiene unit, and the spectrum derived from the hydrogenated polybutadiene unit is obtained, and the spectrum derived from the polybutadiene unit and the hydrogenated polybutadiene unit are obtained. By calculating the ratio of the intensity of the spectrum derived from the polybutadiene unit having a 1,2-vinyl group in the sum of the intensity of the spectrum derived from 1,1, the total amount of the polybutadiene unit and the hydrogenated polybutadiene unit is 100 mol%. The content of polybutadiene units having a 2-vinyl group can be determined.

  The number average molecular weight of the hydride of polybutadiene polyol used in the polyurethane resin composition of the present invention is 1500-2500. By setting the number average molecular weight within the above range, the polyurethane resin composition of the present invention exhibits a better hardness after a heat resistance test, and the initial mixing viscosity does not become too high and exhibits excellent workability. Can do. The number average molecular weight is preferably 1500 to 2200, and more preferably 1500 to 2000.

  In the present specification, the number average molecular weight can be measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight according to the GPC method was measured using Shodex GPC System 21 manufactured by Showa Denko KK as a measuring device, and Shodex LF-804 / KF-803 / KF-804 manufactured by Showa Denko KK as a column. Using NMP as a mobile phase, it can be measured under a column temperature of 40 ° C. and calculated using a standard polystyrene calibration curve.

  The polybutadiene polyol hydride used in the polyurethane resin composition of the present invention preferably has an average hydroxyl value of 20 to 120 mgKOH / g, more preferably 45 to 100 mgKOH / g. When the average hydroxyl value is in the above range, the polyurethane resin composition of the present invention can exhibit more excellent heat resistance.

  The hydride of the polybutadiene polyol is prepared by hydrogenating the polybutadiene polyol. In the polybutadiene polyol used for the hydrogenation, the content of the polybutadiene unit having a 1,2-vinyl group with respect to 100 mol% of the polybutadiene unit is preferably 90 mol% or less, and more preferably 85 mol% or less. 80 mol% or less is more preferable, and 70 mol% or less is particularly preferable. By using such a polybutadiene polyol, a hydride of a polybutadiene polyol having a content of polybutadiene units having a 1,2-vinyl group of 7 mol% or less can be easily prepared by the hydrogenation method described later. The number average molecular weight of the prepared polybutadiene polyol hydride can be adjusted to a suitable range.

  The method for hydrogenating the polybutadiene polyol is not particularly limited, and can be hydrogenated by a conventionally known method. Examples of such a method include a hydrogenation method using a catalyst such as nickel, platinum, palladium, a soluble transition metal, and titanium.

  The hydride of the above polybutadiene polyol is preferably produced by saturating 50% or more, with 70% or more being saturated, with the carbon-carbon double bond of the polybutadiene polyol being 100%. More preferably, 90% or more is saturated and more preferably produced, and 95% or more is saturated and produced.

  The content of the hydride of polybutadiene polyol is preferably 1 to 30% by mass, more preferably 1 to 25% by mass, and 5 to 20% by mass with respect to 100% by mass of the polyurethane resin composition. More preferably.

  In addition to the polybutadiene polyol hydride, the hydroxyl group-containing compound may further contain a castor oil-based polyol or a hydride of castor oil-based polyol. Examples of the castor oil-based polyol include castor oil or castor oil derivatives.

  Castor oil derivatives include castor oil fatty acid; castor oil and other oil transesterification products; castor oil and polyhydric alcohol reaction product; castor oil fatty acid and polyhydric alcohol esterification reaction product; Etc.

  Examples of the hydride of castor oil-based polyol include hydrogenated castor oil obtained by hydrogenating castor oil or castor oil fatty acid.

  The castor oil-based polyol and the hydride of castor oil-based polyol may be used singly or as a mixture thereof.

  In the case where the hydroxyl group-containing compound contains at least one selected from polybutadiene polyol and castor oil-based polyol and castor oil-based polyol hydride, it is selected from polybutadiene polyol, castor oil-based polyol and castor oil-based polyol hydride. The mass ratio of at least one is 100% by mass based on the total amount of polybutadiene polyol and at least one selected from castor oil-based polyol and castor oil-based polyol hydride, (polybutadiene polyol): (castor oil-based polyol and castor oil) (At least one selected from hydrides of polyols) = 90% by mass: 10% by mass to 10% by mass: preferably 90% by mass, 80% by mass: 20% by mass to 40% by mass: 60% by mass More like Arbitrariness. When the hydroxyl group-containing compound having the above mass ratio is used, the compatibility with the isocyanate group-containing compound is excellent, and the viscosity of the polyurethane resin composition is lowered, so that the workability can be further improved.

  The hydroxyl group-containing compound contains, in addition to at least one selected from hydrides of the above polybutadiene polyols, and castor oil-based polyols and hydrides of castor oil-based polyols, various types of compounds conventionally used as hydroxyl group-containing compounds. May be. Examples of the conventional hydroxyl group-containing compounds include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 2methyl 1,3-propanediol, 1,4-butanediol, , 3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,2-hexanediol, 2,5-hexanediol, octanediol, Nonanediol, decanediol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexanediol, trimethylolpropane, glycerin, 2-methylpropane-1,2,3-triol, 1,2,6-hexanetriol, pentaerythritol , Polylactone geo Hydrogen, polylactone triol, ester glycol, polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol, silicone polyol, fluorine polyol, polytetramethylene glycol, polypropylene glycol, polyethylene glycol, polycaprolactone polyol, hydroxyl-containing liquid polyisoprene And the like.

  In the polyurethane resin composition of the present invention, the amount of the hydroxyl group-containing compound used is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, with the polyurethane resin composition being 100% by mass.

  In the polyurethane resin composition of the present invention, the NCO / OH ratio between the isocyanate group-containing compound and the hydroxyl group-containing compound is preferably 0.6 to 2.0, and preferably 0.7 to 1.5. Is more preferable, and it is still more preferable that it is 0.8-1.2. If the NCO / OH ratio is too small, the moisture resistance of the polyurethane resin composition may be reduced. If the NCO / OH ratio is too large, the polyurethane resin composition may cause poor curing.

(Inorganic filler)
The polyurethane resin composition of the present invention contains an inorganic filler. It does not specifically limit as said inorganic filler, A conventionally well-known inorganic filler can be used. Examples of such inorganic fillers include alumina, aluminum hydroxide, aluminum nitride, boron nitride, magnesium hydroxide, and magnesium oxide. Among these, since it is excellent in heat dissipation, examples thereof include alumina, magnesium oxide, aluminum nitride, boron nitride, zeolite, etc., but in terms of excellent flame retardancy, metal hydrated compounds such as aluminum hydroxide and magnesium hydroxide. Is preferred.

  In the polyurethane resin composition of the present invention, the content of the inorganic filler is preferably 50 to 85% by mass and more preferably 50 to 70% by mass with respect to 100% by mass of the polyurethane resin composition. When there is too little content of an inorganic filler, there exists a possibility that a polyurethane resin composition may be inferior to a flame retardance. When there is too much quantity of an inorganic filler, there exists a possibility that the mixing viscosity at the time of manufacture of a polyurethane resin composition may become high, and workability | operativity may fall.

(Plasticizer)
The polyurethane resin composition of the present invention contains a plasticizer. The plasticizer is not particularly limited, and a conventionally known plasticizer can be used. Examples of such plasticizers include phthalic acid esters such as dioctyl phthalate, diisononyl phthalate, and diundecyl phthalate, adipic acid esters such as dioctyl adipate and diisononyl adipate, methyl acetyl ricinoleate, butyl acetyl ricinoleate, and acetylated ricinoleic acid. Castor oil ester such as triglyceride, acetylated polyricinoleic acid triglyceride, trimellitic acid ester such as trioctyl trimellitate, triisononyl trimellitate, pyromellitic acid such as tetraoctyl pyromellitate, tetraisononyl pyromellitate Examples include esters. Of these, trimellitic acid ester is more preferable.

  In the polyurethane resin composition of the present invention, the content of the plasticizer is preferably 1 to 20% by mass and more preferably 5 to 15% by mass with respect to 100% by mass of the polyurethane resin composition. By making content of a plasticizer into the said range, the polyurethane resin composition of this invention shows the outstanding heat resistance, and the increase in a viscosity is suppressed and more workability | operativity can be shown.

(Other additives)
Various additives such as a catalyst, an antioxidant, a hygroscopic agent, an antifungal agent, and a silane coupling agent can be added to the polyurethane resin composition of the present invention as necessary.

  Although it does not specifically limit as a catalyst, The conventionally well-known catalyst used for a urethane resin composition can be used. Examples of such catalysts include tin catalysts such as dioctyltin dilaurate, dibutyltin dilaurate and dioctyltin diacetate; lead catalysts such as lead octylate, lead octenoate and lead naphthenate; bismuth such as bismuth octylate and bismuth neodecanoate. Examples of the catalyst include amine catalysts such as diethylenetriamine. In addition, as the catalyst, an organometallic compound, a metal complex compound, or the like may be used.

  The amount of these additives to be used may be appropriately determined in accordance with the purpose of use from a range similar to the usual amount of addition so as not to hinder the desired properties of the polyurethane resin composition.

  When the polyurethane resin composition of the present invention is a liquid before curing, the viscosity is preferably 500 to 200,000 mPa · s, more preferably 500 to 100,000 mPa · s. By setting the viscosity within the above range, the polyurethane resin composition of the present invention can exhibit higher workability.

  In addition, in this specification, the viscosity of the polyurethane resin composition before hardening is a value measured by the measuring method shown below. That is, a component containing a hydroxyl group-containing compound was prepared to be a B component (polyol component), mixed at 2000 rpm for 3 minutes using a mixer (trade name: Awatori Netaro, manufactured by Shinki Co., Ltd.), and then adjusted to 23 ° C. To do. Separately, a component containing an isocyanate group-containing compound is prepared as component A (polyisocyanate component) and adjusted to 23 ° C. Next, the A component is added to the B component and mixed for 60 seconds. The viscosity of the mixed solution after 3 minutes from the start of mixing is measured using a BH viscometer, and is used as a measured value of the viscosity (mixed initial viscosity) of the polyurethane resin composition before curing.

(Production method)
It does not specifically limit as a method to manufacture the polyurethane resin composition of this invention, It can manufacture by the conventionally well-known method used as a method of manufacturing a polyurethane resin composition.

  As such a production method, for example, a component containing an isocyanate group-containing compound is prepared, a component A, a component containing a hydroxyl group-containing compound is prepared as a component B, and the reaction is performed by mixing the component A and the component B. Examples of the polyurethane resin include a method for producing a polyurethane resin composition containing the polyurethane resin.

  As long as the A component contains an isocyanate group-containing compound and the B component contains a hydroxyl group-containing compound, the other component may be contained in either the A component or the B component. Especially, the structure by which the inorganic filler is contained in B component is preferable. By setting it as such a structure, the hardening defect of the polyurethane resin by the water | moisture content contained in an inorganic filler and a polyisocyanate group containing compound can be suppressed.

  As a combination of the composition of the A component and the B component, specifically, the A component contains only an isocyanate group-containing compound, the B component is a hydroxyl group-containing compound, an inorganic filler, a plasticizer, and the additives described above. The structure containing is preferable. By setting it as such a structure, A component and B component are excellent in liquid stability. Further, the component A contains an isocyanate group-containing compound and a plasticizer, the component B contains a hydroxyl group-containing compound, an inorganic filler and the above-mentioned additive, and the component A is an isocyanate group-containing compound, a plasticizer and an inorganic filler. The B component may contain a hydroxyl group-containing compound and a plasticizer. Moreover, except an isocyanate group containing compound and a hydroxyl group containing compound, it is not contained in A component and B component, but may be separately prepared and added as C component.

  The polyurethane resin composition may be liquid before curing or may be cured. As a method of curing the polyurethane resin composition, the polyurethane resin composition is changed over time by mixing the A component and the B component to react the isocyanate group-containing compound with the hydroxyl group-containing compound to obtain a polyurethane resin. Although the method of making it harden | cure is mentioned, you may make it harden | cure by heating. In this case, the heating temperature is preferably about 40 to 120 ° C., and the heating time is preferably about 0.1 to 24 hours.

(Encapsulant)
The present invention is also a sealing material comprising the polyurethane resin composition. Since the sealing material made of the polyurethane resin composition is made of the polyurethane resin composition after being cured, it can exhibit flexibility for a long period of time, and can exhibit excellent heat resistance and moisture resistance.

(Electrical and electronic parts)
The present invention is also an electrical and electronic component sealed with a resin using the sealing material. The electrical / electronic component of the present invention is such that the sealing material can exhibit flexibility for a long period of time and exhibits excellent heat resistance and moisture resistance. In addition, it can be suitably used as an electric / electronic component that generates heat. Examples of such electric and electronic parts include transformers such as transformer coils, choke coils, and reactor coils, equipment control bases, various sensors, and the like. The electric / electronic parts of the present invention can be used in electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, electric tools, automobiles, motorcycles, and the like.

  The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

The raw materials used in the examples and comparative examples are shown below.
・ GI-1000: Polybutadiene polyol hydride, Nippon Soda Co., Ltd., 1,2-vinyl group content less than 7 mol%, Mn = 1500, viscosity 105Poise / 45 ℃, Tg-44 ℃
・ GI-2000: Polybutadiene polyol hydride manufactured by Nippon Soda Co., Ltd., 1,2-vinyl group content less than 7 mol%, Mn = 2000, viscosity 165 Poise / 45 ℃, Tg-42 ℃
・ GI-3000: Polybutadiene polyol hydride manufactured by Nippon Soda Co., Ltd., 1,2-vinyl group content less than 7 mol%, Mn = 3100, viscosity 315 Poise / 45 ℃, Tg-37 ℃
・ G-1000: Polybutadiene polyol Nippon Soda Co., Ltd., 1,2-vinyl group content 85 mol%, Mn = 1400, viscosity 75Poise / 45 ℃, Tg-25 ℃
・ G-2000: Polybutadiene polyol Nippon Soda Co., Ltd., 1,2-vinyl group content 88 mol%, Mn = 1900, viscosity 140 Poise / 45 ℃, Tg-19 ℃
Castor oil Product name: Castor oil Ito Oil Co., Ltd.)
・ SR-309: Hydrogenated castor oil, manufactured by Ito Oil Co., Ltd., hydroxyl group content = 1.67 mol / kg, viscosity = 2200 mPa · s (25 ° C) Product name: SR-309
・ DINP: diisononyl phthalate plasticizer J-PLUS Co., Ltd. Product name: DINP
・ H-32: Aluminum hydroxide Showa Denko ・ H-42I: Aluminum hydroxide Showa Denko ・ SC-5570: Antifoaming agent ・ Toray Dow Corning ・ U-810: Dioctyltin dilaurate Polymerization catalyst Nitto Kasei Co., Ltd. Company-MTL: Diphenylmethane diisocyanate (MDI) -based isocyanate Tosoh Corporation (trade name: Millionate MTL)
TLA-100: Isocyanurate-modified product of hexamethylene diisocyanate manufactured by Asahi Kasei Chemicals Corporation (trade name: Duranate TLA-100)

(Preparation of polyurethane resin composition)
Raw materials for blending the polyol components shown in Table 1 were charged into a reaction kettle equipped with heating, cooling and decompression devices, and dehydrated at 100 ° C. under a pressure of 10 mmHg or less for 2 hours to prepare polyol components.

  As the polyisocyanate component, isocyanate group-containing compounds shown in Table 1 were prepared.

  A polyurethane resin composition was obtained by adding the polyisocyanate component to the polyol component, stirring, defoaming and mixing in the blending amounts shown in Table 1. Mixing of the polyol component and the polyisocyanate component is performed by adjusting the polyol component to 23 ° C., then adding the polyisocyanate component adjusted to 23 ° C., and using a rotation / revolution mixer (Awatori Kentaro, manufactured by Shinky Corp.) Then, it was carried out by stirring for 1 minute at a rotational speed of 2000 rpm.

  In addition, the compounding ratio of the polyisocyanate component and the polyol component was prepared such that the active hydrogen in the polyol component was 1 equivalent with respect to 1 equivalent of the isocyanate group in the polyisocyanate component.

(Creation of specimen)
The prepared polyurethane resin composition was poured into a molding die having an inner diameter of 30 mm and a height of 10 mm. After heating at 60 ° C. for 16 hours, the test piece was prepared by allowing to stand at room temperature for 1 day to cure. Using the prepared test pieces, tests for high temperature durability and moisture resistance were conducted by the following methods.

  The following tests were performed using the polyurethane resin compositions of Examples and Comparative Examples prepared as described above.

The viscosity of the polyurethane resin composition before workability curing was measured by the following measurement method. That is, a component containing a hydroxyl group-containing compound was prepared and used as a polyol component. After mixing for 3 minutes at 2000 rpm using a mixer (trade name: Awatori Netaro, manufactured by Shinki Co., Ltd.), the temperature was adjusted to 23 ° C. Separately, a component containing an isocyanate group-containing compound was prepared as a polyisocyanate component and adjusted to 23 ° C. Next, the polyisocyanate component was added to the polyol component and mixed for 60 seconds. The viscosity of the mixed solution 3 minutes after the start of mixing was measured using a BH viscometer, and the initial mixing viscosity of the polyurethane resin composition before curing was measured. Workability was evaluated according to the following evaluation criteria based on the measured initial viscosity of mixing.
○: Viscosity is 50000 mPa · s or less Δ: Viscosity exceeds 50000 mPa · s ×: Liquid component cannot be created Note that if it is Δ evaluation or more, it is judged that it can be used in actual use.

In an atmosphere having a pot life of 23 ° C., the time until the viscosity became twice the initial mixing viscosity measured by the above method was measured. Based on the measured time, the pot life was evaluated according to the following evaluation criteria.
○: More than 30 minutes Δ: 10 minutes or more and 30 minutes or less ×: less than 10 minutes In addition, if it is Δ evaluation or more, it is judged that it can be used in actual use.

Hardness (type A) was measured by a measuring method in accordance with JIS K6253 using a test piece prepared by curing a polyurethane resin composition.

High Temperature Durability The hardness (type A) of a test piece prepared by curing a polyurethane resin composition was measured by the above hardness measurement method. Subsequently, using the test piece, it heated on the conditions of 150 degreeC and 100 hours, and the hardness (type A) after a heating was measured according to JISK6253. The ratio (%) of the amount of change in hardness after heating from the hardness before heating was calculated with the hardness before heating as 100%, and was defined as the rate of change in hardness. Based on the calculated hardness change rate, high temperature durability was evaluated according to the following evaluation criteria.
◯: Hardness change rate is less than 50% Δ: Hardness change rate is 50 to 70%
X: Hardness change rate exceeds 70%

Moisture resistance The hardness (type A) of a test piece prepared by curing the polyurethane resin composition was measured by the above hardness measurement method. Next, a pressure cooker test was performed using the test piece under the conditions of 121 ° C., 100% RH, and 200 hours. The hardness after pressure cooker test (type A) is measured according to JIS K6253, the ratio (%) of hardness after pressure cooker test to the hardness before pressure cooker test is calculated as the hardness retention, and the moisture resistance according to the following evaluation criteria Evaluated.
◯: Hardness retention is 50% or more Δ: Hardness retention is 20% or more and less than 50% x: Hardness retention is less than 20% The results are shown in Table 1.

  The polyurethane resin composition of the present invention is excellent in workability, the cured polyurethane resin can exhibit flexibility for a long time, and can exhibit excellent heat resistance and moisture resistance. For this reason, it can be used in the field of electrical products and the like.

Claims (4)

A polyurethane resin composition comprising an isocyanate group-containing compound and a hydroxyl group-containing compound, a polyurethane resin composition containing an inorganic filler and a plasticizer,
The hydroxyl group-containing compound contains a hydride of polybutadiene polyol,
The hydride of the polybutadiene polyol has a content of polybutadiene units having 1,2-vinyl groups of 7 mol% or less with respect to a total amount of 100 mol% of polybutadiene units and hydrogenated polybutadiene units, and has a number average molecular weight of 1500. ~ 2500,
The hydride of the polybutadiene polyol is a hydride of 1,2-polybutadiene polyol,
The hydroxyl group-containing compound further includes at least one selected from a castor oil-based polyol and a hydride of castor oil-based polyol,
A polyurethane resin composition characterized by that.   The polyurethane resin composition according to claim 1, wherein the isocyanate group-containing compound contains an isocyanurate-modified product of hexamethylene diisocyanate. Sealing material made of a polyurethane resin composition according to claim 1 or 2. An electrical / electronic component sealed with a resin using the sealing material according to claim 3 .