JP6076399B2 - Polyurethane resin composition - Google Patents

Description

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

  In recent years, the density and integration of electric and electronic parts have been increased, and improvement of reliability is required for each part. In particular, electrical and electronic parts used in car engines, water heaters, and the like are required to have high reliability not only for moisture resistance at room temperature but also for moisture resistance in a high temperature environment.

  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 such a sealing material has hydrolysis resistance, flame retardancy to suppress ignition of electrical and electronic parts, insulation is not lost even in a high temperature and high humidity environment, flexible Properties (appropriate hardness) are required.

  Patent Document 1 proposes to use a polyether polyol in which butylene oxide is added to a polyol having three or more hydroxyl groups as a polyurethane resin composition having heat and moisture resistance.

JP 2014-9308 A

  However, in patent document 1, flame retardance and hardness are not examined, and it is considered that there is room for improvement in hydrolysis resistance and the like. In particular, electrical and electronic parts used in car engines, water heaters and the like are used for a long time in a high-temperature and high-humidity environment, so that the polyurethane resin that seals them is hydrolyzed and its shape is deformed. (Or it becomes easy to deform). For this reason, it is important that the polyurethane resin composition used for sealing such electric and electronic parts is resistant to hydrolysis, and particularly, does not deform even in a high temperature and high humidity environment.

  Then, this invention makes it a subject to provide the polyurethane resin composition which was excellent in hydrolysis resistance, especially the deformation | transformation in a high-temperature, high-humidity environment was suppressed more. Another object of the present invention is to provide a polyurethane resin composition that is excellent in flame retardancy and flexibility, and that further suppresses a decrease in insulation under a high temperature and high humidity environment.

  As a result of diligent research in view of the above problems, the present inventors have added hydrolysis resistance by adding polyisocyanate containing a biuret group in the molecule, polyether polyol, castor oil-based polyol, and zeolite. It has been found that an excellent polyurethane resin composition can be provided which is more excellent in deformation, particularly under high-temperature and high-humidity environments, and excellent in flexibility. Further research based on this finding has led to the completion of the present invention.

That is, the present invention includes the following aspects.
Item 1. A polyurethane resin composition (hereinafter also referred to as “polyurethane resin composition of the present invention”) characterized by containing polyisocyanate containing biuret group in the molecule, polyether polyol, castor oil-based polyol, and zeolite. is there).
Item 2. Item 2. The polyurethane resin composition according to Item 1, wherein a content of the castor oil-based polyol is 70 to 99% by mass with respect to 100% by mass in total of the polyether polyol and the castor oil-based polyol.
Item 3. Item 3. The polyurethane resin composition according to Item 1 or 2, further comprising a phosphate ester flame retardant.
Item 4. Item 4. The polyurethane resin composition according to any one of Items 1 to 3, wherein a content of the phosphate ester is 10 to 30% by mass with respect to 100% by mass of the polyurethane resin composition.
Item 5. The polyurethane resin composition according to any one of Items 1 to 4, further comprising a dimer acid polyol.
Item 6. Item 6. The polyurethane resin composition according to any one of Items 1 to 5, wherein an NCO / OH ratio of the polyisocyanate, the polyether polyol, and the castor oil-based polyol is 0.7 to 1.0.
Item 7. Item 7. The polyurethane resin composition according to any one of Items 1 to 6, which is used for sealing electric and electronic parts.
Item 8. Item 8. An electrical / electronic component sealed with the polyurethane resin composition according to any one of Items 1 to 7.

  The polyurethane resin composition of the present invention is more excellent in hydrolysis resistance, and in particular, deformation under a high temperature and high humidity environment is further suppressed. Moreover, it is excellent also in a flame retardance and a softness | flexibility, and also the fall of the insulation in a high temperature, high humidity environment is suppressed more. Therefore, it is particularly suitable for sealing electrical and electronic parts used in a high temperature and high humidity environment. Moreover, the electrical / electronic component encapsulated with the polyurethane resin composition of the present invention exhibits high reliability even in a high temperature and high humidity environment.

  In this specification, the expression “containing” includes the concepts of “including”, “consisting essentially of”, and “consisting only of”. Further, the expression “hydrogenated” means a hydrogen adduct.

1. Polyurethane resin composition The polyurethane resin composition of the present invention is characterized by containing polyisocyanate containing biuret groups in the molecule, polyether polyol, castor oil-based polyol, and zeolite. This will be described below.

  The polyisocyanate containing a biuret group in the molecule is not particularly limited as long as it is a compound having two or more isocyanate groups and containing a biuret group represented by the following general formula (1) in the molecule. A polyurethane resin composition It is possible to use various types used in the above.

  Examples of the polyisocyanate containing a biuret group in the molecule include biuret bodies such as aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds, and araliphatic polyisocyanate compounds. Among these, from the viewpoint that the effects of the present invention can be more reliably exhibited, biuret bodies such as aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds are preferable, and biurets of aliphatic polyisocyanate compounds are more preferable. The body is mentioned.

  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, Examples include 2-methylpentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate, and preferably hexamethylene diisocyanate (HDI).

  Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis (isocyanate methyl). And cyclohexane.

  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, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like can be mentioned.

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

  Examples of commercially available polyisocyanates containing biuret groups in the molecule include Duranate 24A-100 (HDI-based isocyanurate, manufactured by Asahi Kasei Chemicals), Duranate 22A-75P (HDI-based isocyanurate, manufactured by Asahi Kasei Chemicals), Duranate 21S-75E ( HDI type isocyanurate manufactured by Asahi Kasei Chemicals Corporation).

  As the polyisocyanate containing a biuret group in the molecule, one kind may be used alone, or two or more kinds may be mixed and used.

  In the polyurethane resin composition of the present invention, the content of the polyisocyanate containing a biuret group in the molecule is not particularly limited, but is preferably 1 to 60% by mass with respect to 100% by mass of the total polyol, 60 mass% is more preferable, 25-60 mass% is more preferable, 35-60 mass% is more preferable, 45-60 mass% is more preferable.

  The polyurethane resin composition of the present invention may contain other polyisocyanates in addition to the polyisocyanate containing a biuret group in the molecule as long as the desired effect of the present invention can be exhibited. In the polyurethane resin composition of the present invention, the polyisocyanate containing a biuret group in the molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 90% by mass with respect to 100% by mass of the total amount of polyisocyanate. % Or more. Examples of other polyisocyanates include the above-mentioned aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds, and araliphatic polyisocyanate compounds. Furthermore, these isocyanurates, carbodiimides, adducts, etc. Is mentioned. When other polyisocyanates are included, it is preferable that the total amount of polyisocyanate with respect to 100% by mass of the total amount of polyol falls within the above-described content range of the polyisocyanate containing biuret groups in the molecule.

  The castor oil-based polyol is not particularly limited as long as it is a castor oil-based polyol having two or more hydroxyl groups, and various types of those used in the polyurethane resin composition can be used.

  Specific examples of the castor oil-based polyol include castor oil and castor oil derivatives. The castor oil derivative is not particularly limited. For example, castor oil fatty acid; hydrogenated castor oil hydrogenated to castor oil or castor oil fatty acid; transesterified product of castor oil and other fats and oils; castor oil and polyhydric alcohol Reaction product: Esterification reaction product of castor oil fatty acid and polyhydric alcohol; those obtained by addition polymerization of alkylene oxide to these.

  The number average molecular weight of the castor oil-based polyol is usually in the range of 100 to 4000, and preferably in the range of 300 to 2500.

  In the castor oil-based polyol, the hydroxyl group content is usually in the range of 30 to 500 mgKOH / g, preferably in the range of 100 to 200 mgKOH / g, as the hydroxyl value.

  Examples of commercially available products that can be used as a castor oil-based polyol include Eulic Y-403 (hydroxyl value 160, functional group number 2), Eulic H-30 (hydroxyl value 160, functional group number 3), Eulic H manufactured by Ito Oil Co., Ltd. -57 (hydroxyl value 100, functional group number 3), Euric H-52 (hydroxyl value 200, functional group number 3) and the like.

  The number average molecular weight can be measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight by the GPC method is 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. Measured at a column temperature of 40 ° C. using NMP as a mobile phase, and can be calculated using a standard polystyrene calibration curve.

  The castor oil-based polyol may be used alone or in combination of two or more.

  Although there is no restriction | limiting in particular in content of the castor oil type | system | group polyol with respect to 100 mass% of polyurethane resin compositions of this invention, From a viewpoint that the effect of this invention can be exhibited more reliably, 10-65 mass% is preferable, and 20 -65 mass% is more preferable, and 25-60 mass% is more preferable.

  Although there is no restriction | limiting in particular in content of the castor oil type polyol with respect to a total of 100 mass% of a castor oil type polyol and a polyether polyol, From a viewpoint that the fall of insulation in a high temperature, high humidity environment can be suppressed more. 70-99 mass% is preferable, and 75-98 mass% is more preferable.

  The polyether polyol is not particularly limited as long as it is a polyether polyol having two or more hydroxyl groups, and various kinds of those used in the polyurethane resin composition can be used.

  Examples of the polyether polyol include those produced by addition polymerization of ethylene oxide or propylene oxide (preferably propylene oxide) to an initiator.

  Examples of the initiator include initiators having 2 functional groups such as propylene glycol, ethylene glycol, and bisphenol A; initiators having 3 functional groups such as glycerin, trimethylolpropane, and triethanolamine; pentaerythritol, ethylenediamine, and aroma Initiators having 4 functional groups such as group diamines; initiators having 5 functional groups such as diethylenetriamine; initiators having 5 functional groups such as sorbitol; initiators having 8 functional groups such as sucrose. Among these, preferably an initiator having 2 to 4 functional groups, more preferably an initiator having 2 to 3 functional groups, more preferably propylene glycol, ethylene glycol, glycerin, trimethylolpropane, triethanolamine and the like. It is done.

  The number average molecular weight of the polyether polyol is usually in the range of 100 to 4000, preferably in the range of 200 to 3000.

  Examples of commercially available products that can be used as the polyether polyol include T-400 and P-1000 manufactured by ADEKA.

  A polyether polyol may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The content of the polyether polyol with respect to 100% by mass of the polyurethane resin composition of the present invention is not particularly limited, but is preferably 0.1 to 20% by mass from the viewpoint that the effects of the present invention can be more reliably exhibited. 0.5-15 mass% is more preferable, and 1.5-15 mass% is more preferable.

  The content of the polyether polyol with respect to the total of 100% by mass of the castor oil-based polyol and the polyether polyol is not particularly limited, but from the viewpoint that it is possible to further suppress a decrease in insulation under a high temperature and high humidity environment. 1-30 mass% is preferable and 2-25 mass% is more preferable.

The polyurethane resin composition of the present invention preferably further contains a dimer acid polyol as a polyol. By containing the dimer acid polyol, the insulation can be further improved. Examples of the dimer acid polyol include the following reaction products (1) to (4) or a mixture thereof.
(1) a reaction product of a dimer acid and a short-chain diol (dihydric alcohol), triol (trihydric alcohol) or polyol (tetrahydric or higher alcohol);
(2) reaction product of dimer acid and polyalkylene glycol, polyalkylene triol or long-chain polyol;
(3) a reaction product obtained by reacting the above-mentioned short-chain diol, triol, or polyol with a mixture of dimer acid and another polycarboxylic acid such as adipic acid, and (4) dimer acid and alkylene oxide ( For example, reaction products with ethylene oxide, propylene oxide, etc.)

  The dimer acid is a dibasic acid, and two monobasic fatty chains (usually having 18 carbon atoms) have a molecular weight obtained by doubling the molecular weight of two by a carbon-carbon covalent bond. Refers to basic acid. The typical compound is a dimer obtained by polymerization of unsaturated fatty acids such as linoleic acid, oleic acid, elaidic acid, tall oil fatty acid and the like. Generally, since the unsaturated fatty acid having 18 carbon atoms is used as a raw material, the main component is a dicarboxylic acid having 36 carbon atoms. The dimer acid may contain a trimer and / or a monomer.

  Examples of the short-chain diol include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol 2,2,4-trimethyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol, 1,10-decanediol, etc. To 10 diols.

  Examples of the short-chain triol include triols having 3 to 10 carbon atoms such as glycerin and trimethylolpropane (TMP).

  Examples of the short-chain polyol include C3-C10 polyols such as tetramethylolmethane and pentaerythritol.

  Examples of the polyalkylene glycol include polyalkylene glycols having 10 to 500 carbon atoms such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and ethylene glycol-propylene glycol copolymer.

  Examples of the polyalkylene triol include polyalkylene triols having 10 to 500 carbon atoms such as polypropylene oxide triol, polyethylene oxide triol, polypropylene oxide / polyethylene oxide copolymer triol.

  Examples of the long-chain polyol include polyols having 11 to 500 carbon atoms such as polypropylene glycol.

  The weight average molecular weight (Mw) of the dimer acid polyol is usually in the range of 300 to 50000, preferably in the range of 300 to 10000, more preferably in the range of 300 to 3000.

  The dimer acid polyol has an average number of functional groups per molecule of 2 to 4 (preferably 2 to 3), a hydroxyl value of 2 to 10000 mgKOH / g, more preferably 30 to 500 mgKOH / g. Preferably, it is 30-300.

  A commercially available product can be used as the dimer acid polyol. For example, Pripol 2033-LQ- (GD) (average hydroxyl value: 202 to 212 mgKOH / g, average number of functional groups: 2) manufactured by Croda Japan, Hitachi Chemical TA22-558 (hydroxyl value: 70 to 75 mgKOH / g, average functional group number: 3), TA22-559 (hydroxyl value: 78 to 82 mgKOH / g, average functional group number: 3), Edifice E manufactured by Kao Corporation -404 (hydroxyl value: 120 mgKOH / g, average number of functional groups: 3) and the like.

  The blending amount of the dimer acid polyol is not particularly limited, but is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, with respect to 100% by mass of the polyurethane resin composition. More preferably, it is -25 mass%.

  In the polyurethane resin composition of the present invention, as long as the desired effect of the present invention can be exhibited, in addition to the castor oil-based polyol that is an essential polyol, the polyether polyol, and the dimer acid polyol that is an optional polyol. Alternatively, other polyols may be contained. In the polyurethane resin composition of the present invention, the total content of the castor oil-based polyol, the polyether polyol, and the dimer acid polyol with respect to 100% by mass of the total amount of polyol is preferably 80% by mass or more, and 95% by mass or more. Is more preferable, and 99 mass% or more is still more preferable. Examples of other polyols include, but are not limited to, polybutadiene polyol, polyester polyol, polycarbonate polyol, polyisoprene polyol, hydrogenated product of polyisoprene polyol, and the like.

  In the polyurethane resin composition of the present invention, NCO / OH of polyisocyanate (polyisocyanate containing biuret group in the molecule and other polyisocyanates) and polyol (polyether polyol, castor oil-based polyol, and other polyol) The ratio is preferably 0.7 to 1.0 and more preferably 0.8 to 1.0 from the viewpoint of further improving the flame retardancy.

  The zeolite is not particularly limited, and various types of zeolite used in the polyurethane resin composition can be used.

  As the zeolite, for example, a crystalline hydrous aluminosilicate of an alkali metal or an alkaline earth metal is preferable.

  The crystal form of zeolite is not particularly limited, and examples include A type, X type, and LSX type. Among these, A type is preferable.

  The alkali metal or alkaline earth metal in the zeolite is not particularly limited, and examples thereof include potassium, sodium, calcium, and lithium. Among these, potassium is preferable.

  The average pore diameter of zeolite is preferably about 0.3 to 1.0 nm, and more preferably about 0.3 to 0.5 nm.

  Although the average particle diameter of a zeolite is not specifically limited, For example, it is 0.1-10 micrometers, Preferably it can be about 0.1-5 micrometers.

  One kind of zeolite may be used alone, or two or more kinds may be mixed and used.

  The content of zeolite is preferably 0.1 to 5% by mass and more preferably 0.3 to 3% by mass with respect to 100% by mass of the polyurethane resin composition.

  The polyurethane resin composition of the present invention preferably contains a phosphate ester flame retardant. The phosphate ester flame retardant is not particularly limited as long as it is a flame retardant containing phosphorus, and various types of those used in polyurethane resin compositions can be used. Examples of phosphate ester flame retardants include trimethyl phosphate (TMP), triethyl phosphate (TEP), triphenyl phosphate (TPP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), cresyl diphenyl phosphate. (CDP), non-halogen esters such as cresyl di-2,6-xylenyl phosphate; non-halogen condensed phosphates such as aromatic condensed phosphates. Among these, trixylenyl phosphate is preferable.

  The phosphate ester flame retardant may be used alone or in combination of two or more.

  The viewpoint that the content of the phosphate ester-based flame retardant can further improve the hydrolysis resistance and further suppress the deterioration of the insulating property in a high-temperature and high-humidity environment while imparting appropriate flame retardancy. Is preferably 10 to 30% by mass and more preferably 15 to 30% by mass with respect to 100% by mass of the polyurethane resin composition.

  The polyurethane resin composition of the present invention may contain a polymerization catalyst as necessary.

  A polymerization catalyst is not specifically limited, What is used in a polyurethane resin composition can be used variously. As a polymerization catalyst, metal catalysts, such as an organic tin catalyst, an organic lead catalyst, and an organic bismuth catalyst, an amine catalyst etc. can be illustrated, for example. Examples of the organic tin catalyst include dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin diacetate. Examples of the organic lead catalyst include lead octylate, lead octenoate, lead naphthenate and the like. Examples of the organic bismuth catalyst include bismuth octylate and bismuth neodecanoate. As amine catalysts, diethylenetriamine, triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, trimethylene Examples thereof include diamine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ether and the like. Moreover, as a polymerization catalyst, you may use an organometallic compound, a metal complex compound, etc.

  A polymerization catalyst may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The content of the polymerization catalyst is preferably 0.00001 to 10% by mass and more preferably 0.0001 to 5% by mass with respect to 100% by mass of the polyurethane resin composition of the present invention.

  The polyurethane resin composition of the present invention may contain an antioxidant as necessary.

  An antioxidant is not specifically limited, What is used in a polyurethane resin composition can be used variously. Examples of the antioxidant include naphthylamine, diphenylamine, p-phenylenediamine, quinoline, hydroquinone, monophenol, polyphenol, thiobisphenol, hindered phenol, phenol and phosphite. And organic sulfur compounds.

  An antioxidant may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  0.001-1 mass% is preferable with respect to 100 mass% of polyurethane resin compositions of this invention, content of antioxidant is more preferable 0.01-0.5 mass%, 0.05-0. 2% by mass is more preferable.

  The polyurethane resin composition of the present invention may contain a plasticizer, an inorganic filler, a tackifier, a colorant, a chain extender, a crosslinking agent, an ultraviolet absorber, a moisture absorbent, an antifoaming agent, and an antifungal agent as necessary. Further, additives such as a silane coupling agent can be further blended.

  The amount of these components used may be appropriately determined according to the purpose of use so as not to inhibit the desired properties of the finally obtained polyurethane resin composition.

2. Manufacturing method of polyurethane resin composition 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 step of preparing a composition (B agent) containing a polyol (step 1), a step of preparing a composition (A agent) containing a polyisocyanate (step 2), and A The method including the process (process 3) which mixes an agent and B agent and makes it a polyurethane resin composition is mentioned.

  As long as the B agent contains a polyol and the A agent contains a polyisocyanate, the other component may be contained in either the A agent or the B agent.

  For example, the composition in which the B agent contains polyol and zeolite and the A agent contains polyisocyanate can be mentioned. Another example includes a configuration in which the agent B contains a polyol and the agent A contains a polyisocyanate and a zeolite.

  In the polyurethane resin composition, the polyol and polyisocyanate may partially or completely react to form a polyurethane resin. That is, the polyurethane resin composition may be liquid before curing or may be cured. As a method of curing the polyurethane resin composition, a method of curing the polyurethane resin composition over time by reacting the polyol and the polyisocyanate by mixing the agent A and the agent B to form a polyurethane resin. However, it may be cured by heating. In this case, the heating temperature is preferably about 40 to 120 ° C., and the heating time is preferably about 0.5 to 24 hours.

3. Uses The polyurethane resin composition of the present invention is more excellent in hydrolysis resistance, and in particular, deformation under a high temperature and high humidity environment is further suppressed. Moreover, it is excellent also in a flame retardance and a softness | flexibility, and also the fall of the insulation in a high temperature, high humidity environment is suppressed more. Therefore, it is particularly suitable for sealing electrical and electronic parts (especially electrical and electronic parts used in high temperature and high humidity environments). Moreover, the electrical / electronic component encapsulated with the polyurethane resin composition of the present invention exhibits high reliability even in a high temperature and high humidity environment. In addition, "high temperature" can be about 80-200 degreeC, for example, Preferably it is a temperature range of 90-150 degreeC. The “high humidity” can be a humidity range where the relative humidity is 60% RH or more, preferably 80% RH or more, for example.

  Electric and electronic parts used in a high temperature and high humidity environment include, for example, electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, electric tools, automobiles (especially engines), motorcycles, etc. Electronic parts are mentioned.

  EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

(1) Preparation of polyurethane resin composition A polyurethane resin composition was prepared according to the formulation shown in Table 1. The preparation procedure is as follows. Each material of B agent was put 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 B agent. Similarly, the phosphate ester flame retardant of agent A is put into a reaction kettle equipped with a heating, cooling, and decompression device and dehydrated at 100 ° C. under a pressure of 10 mmHg or less for 2 hours. A polyisocyanate containing a group was added and stirred to prepare agent A. A polyurethane resin composition was obtained by adding A agent in the prepared B agent, stirring, defoaming and mixing. In addition, the mixing of B agent and A agent is carried out by adjusting B agent to 23 ° C., then adding A agent adjusted to 23 ° C., and using a rotation / revolution mixer (Awatori Kentaro, manufactured by Shinky Corporation). Then, it was carried out by stirring for 1 minute at a rotational speed of 2000 rpm.

(2) Preparation of test specimens were prepared into a molding die A having a size of 130 × 130 × 1.5 mm, a molding die B having an inner diameter of 130 mm and a height of 10 mm, and a molding die C having a size of 130 × 130 × 3.0 mm. A polyurethane resin composition was injected. Each was heated at 60 ° C. for 16 hours and then allowed to stand at room temperature for 1 day to be cured to prepare test pieces A to C. Using the prepared test pieces A to C, hardness, flame retardancy, hydrolysis resistance, and insulation after wet heat treatment were examined by the following methods.

(3) The hardness of the specimen B adjusted to a hardness of 23 ° C. was measured using an Asker A type hardness meter (manufactured by Kobunshi Keiki Co., Ltd.) by a measuring method based on JIS K6253. Hardness was evaluated according to the following evaluation criteria.
○: The measured value is less than A70.
X: A measured value is A70 or more.

(4) A flame retardancy test was performed using test piece A which is a polyurethane resin composition after flame retardant curing. The test was conducted by Underwriters Laboratories, Inc., USA. Based on the combustion test standard (UL94) established by Flame retardancy was evaluated according to the following evaluation criteria.
○: V-0
X: V-2 or HB or no flame retardancy.

(5) Hydrolysis resistance The hydrolysis resistance test was conducted by leaving the test piece B in boiling water for 240 hours. The test piece B after the test was adjusted to 23 ° C., the hardness was measured using an Asker A type hardness meter (manufactured by Kobunshi Keiki Co., Ltd.) by a measuring method based on JIS K6253, and the appearance after the test was visually observed. Observed. The hydrolysis resistance was evaluated according to the following evaluation criteria.
○: The measured value is A0 or more and the shape is maintained.
X: The shape is not maintained.

(6) The insulation test piece C after the wet heat treatment was wet heat treated at 85 ° C. × 85% RH × 100 hours. The specimen C after the wet heat treatment was adjusted to 23 ° C., and the volume resistivity was measured. Specifically, using SE-10E manufactured by Toa Denpa Kogyo Co., Ltd., a measurement voltage of 500 V was applied, and the value after 60 seconds was measured. The insulation after wet heat treatment was evaluated according to the following evaluation criteria.
○: Volume resistivity is 10 ⁹ Ω · cm or more ×: Volume resistivity is less than 10 ⁹ Ω · cm.

Claims (4)

A polyurethane resin composition comprising:
Contains polyisocyanate and polyether polyol containing a biuret group in the molecule, castor oil-based polyol, zeolite, and phosphate ester-based flame retardant,
The content of the castor oil-based polyol is 70 to 99% by mass with respect to a total of 100% by mass of the polyether polyol and the castor oil-based polyol,
The content of the phosphate ester flame retardant is 10 to 30% by mass with respect to 100% by mass of the polyurethane resin composition, and
The polyurethane resin composition, wherein an NCO / OH ratio of polyisocyanate and polyol in the polyurethane resin composition is 0.7 to 1.0.   The polyurethane resin composition according to claim 1, further comprising a dimer acid polyol.   The polyurethane resin composition according to claim 1 or 2, which is used for sealing electric and electronic parts.   An electrical / electronic component sealed with the polyurethane resin composition according to claim 1.