JP6285046B2 - Water-based polyurethane resin composition - Google Patents

Description

  The present invention relates to an aqueous polyurethane resin composition.

  Conventionally, electronic circuit boards and electronic components have been sealed using polyurethane resin or the like in order to prevent external contamination. In recent years, there has been a demand for water-based polyurethane resins that do not use organic solvents due to environmental problems. The present inventors are a one-pack type obtained by further reacting a chain extender with a urethane prepolymer obtained by reacting a polyol and polyisocyanate having a specific structure, which is excellent in heat resistance and heat and moisture resistance of a cured product. An aqueous polyurethane resin composition containing an aqueous dispersion of an insulating polyurethane resin has been disclosed (Patent Documents 1 to 3).

JP 2007-31726 A JP 2007-119786 A JP 2007-119787 A

  However, in recent years, due to changes in work processes, water-based polyurethane resin compositions having even better drying properties have been demanded. Then, this invention is made | formed in view of the said problem, and makes it a subject to provide the water-based polyurethane resin composition which is excellent in the heat resistance of a hardened | cured material, heat-and-moisture resistance, and excellent in drying property.

  As a result of intensive studies to solve the above problems, the inventors of the present invention reacted a hydroxyl group-containing compound (A) having a specific structure, an isocyanate group-containing compound (B) and an acidic group-containing polyol (C). An aqueous dispersion of a polyurethane resin (Y) obtained by further reacting a urethane extender (X) obtained in this manner with a chain extender (D) having reactivity with a specific amount of the isocyanate group (X). It has been found that the above problems can be solved by the aqueous polyurethane resin composition contained, and the present invention has been completed.

That is, this invention relates to the invention hung up below.
(1) A urethane prepolymer (X) obtained by reacting a hydroxyl group-containing compound (A) (wherein (A) does not contain an acidic group) , an isocyanate group-containing compound (B) and an acidic group-containing polyol (C ). A water-based polyurethane for an encapsulant for electrical and electronic parts, comprising an aqueous dispersion of a polyurethane resin (Y) obtained by further reacting a chain extender (D) having reactivity with an isocyanate group of (X) A resin composition, wherein the hydroxyl group-containing compound (A) is composed of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, and hydrogenated polyisoprene polyol with respect to 100 parts by mass of the hydroxyl group-containing compound (A). Containing at least 80 parts by mass of one or more selected from (A1), wherein the isocyanate group-containing compound (B) is isophorone. Isocyanate and / or tolylene diisocyanate (B2), the chain extender (D) contains adipic acid dihydrazide, and the content of the chain extender (D) is 100 parts by mass of the polyurethane resin (Y). in contrast, 1-12 parts by weight, the sealing agent aqueous polyurethane resin composition of the electrical and electronic components.
(2) The hydroxyl group-containing compound (A) is 95 masses of one or more (A1) selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol with respect to 100 parts by mass of the hydroxyl group-containing compound (A). containing at least part, (1) a sealing agent aqueous polyurethane resin composition of the electric and electronic component according.
(3) the acid value of (X) is 5 to 40 (mg KOH / g) (1) or (2) a sealing agent aqueous polyurethane resin composition of the electric and electronic component according.
(4) further contains a triazole compound and / or benzimidazole compounds, (1) to (3) sealing agent aqueous polyurethane resin composition of the electrical and electronic components according to any one.
(5) An electrical / electronic component having a dried product of the water-based polyurethane resin composition for a sealant for electrical / electronic components according to any one of (1) to (4).

  ADVANTAGE OF THE INVENTION According to this invention, the water-based polyurethane resin composition which is excellent in the heat resistance of a hardened | cured material, heat-and-moisture resistance, and is excellent also in drying property can be provided.

  The aqueous polyurethane resin composition of the present invention comprises a urethane prepolymer (X) obtained by reacting a hydroxyl group-containing compound (A), an isocyanate group-containing compound (B) and an acidic group-containing polyol (C) with (X) An aqueous dispersion of a polyurethane resin (Y) obtained by further reacting a chain extender (D) having reactivity with an isocyanate group of

  The hydroxyl group-containing compound (A) in the present invention contains one or more (A1) selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, and hydrogenated polyisoprene polyol. Among these, polybutadiene polyol is preferable from the viewpoint of emulsification, and hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol are preferable from the viewpoint of heat resistance. The molecular weight of the hydroxyl group-containing compound (A) is preferably 400 or more from the viewpoint of heat resistance, heat and humidity resistance, flexibility, and low temperature characteristics.

  In the present invention, the content of one or more (A1) selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, and hydrogenated polyisoprene polyol is 100 parts by mass of the hydroxyl group-containing compound (A). 80 parts by mass or more, preferably 90 parts by mass or more, more preferably 95 parts by mass or more. If it is these ranges, it is preferable at the point of heat resistance, heat-and-moisture resistance, a flexibility, and a low temperature characteristic.

  In the present invention, the number average molecular weight of one or more (A1) selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, and hydrogenated polyisoprene polyol is preferably 500 to 5000, and preferably 1000 to 5000, from the viewpoint of emulsifiability. 3000 is more preferable.

  Polyols other than polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol can be blended with the hydroxyl group-containing compound (A) used in the present invention. Such polyol is not particularly limited, and examples thereof include polyether polyol, polyester polyol, and polycarbonate polyol. These can use 1 type, or 2 or more types.

  The polyether polyol is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 4,4′-dihydroxyphenylpropane, 4 Dihydric alcohols such as, 4′-dihydroxyphenylmethane or trihydric or higher polyhydric alcohols such as glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol, pentaerythritol, ethylene oxide, Examples thereof include addition polymers with alkylene oxides such as propylene oxide, butylene oxide and α-olefin oxide.

  The polyester polyol is not particularly limited. For example, it is a reaction product of a fatty acid and a polyol, and the fatty acid is not particularly limited. For example, ricinoleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, Examples thereof include hydroxy-containing long chain fatty acids such as suberic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, oxycaproic acid, oxycapric acid, oxyundecanoic acid, oxylinoleic acid, oxystearic acid, and oxyhexanedecenoic acid. Although it does not specifically limit as a polyol which reacts with a fatty acid, For example, glycols, such as ethylene glycol, propylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, hexamethylene glycol, neopentyl glycol and diethylene glycol, glycerin, Trifunctional polyols such as trimethylolpropane and triethanolamine, tetrafunctional polyols such as diglycerin and pentaerythritol, hexafunctional polyols such as sorbitol, octafunctional polyols such as sugar, alkylene oxides and aliphatics corresponding to these polyols, Examples include addition polymerization products of alicyclic and aromatic amines, addition polymerization products of alkylene oxides and polyamide polyamines, and the like. Of these, glyceride ricinoleate, polyester polyol of ricinoleic acid and 1,1,1-trimethylolpropane, and the like are preferable.

  The isocyanate group-containing compound (B) in the present invention contains aliphatic isocyanate (B1) and / or tolylene diisocyanate (B2).

  The aliphatic isocyanate (B1) is not particularly limited. For example, tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 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. Moreover, modified bodies such as terminal diisocyanate group prepolymers with carbodiimide-modified bodies, isocyanurate bodies, allophanate bodies, and hydroxyl group-containing compounds (A) of aliphatic diisocyanates can also be used. These can use 1 type, or 2 or more types.

  Examples of the tolylene diisocyanate (TDI) (B2) include 2,4-TDI and 2,6-TDI. These modified carbodiimides, isocyanurates, allophanates, terminal isocyanate group prepolymers with a hydroxyl group-containing compound (A), and the like can also be used. These can use 1 type, or 2 or more types.

  An isocyanate group-containing compound other than the aliphatic isocyanate (B1) and / or tolylene diisocyanate (B2) can be blended with the isocyanate group-containing compound (B) used in the present invention. Such an isocyanate group-containing compound is not particularly limited, and examples thereof include alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds other than tolylene diisocyanate (B2), and araliphatic polyisocyanate compounds. In addition, terminal isocyanate group prepolymers with carbodiimide-modified products, isocyanurate bodies, allophanate bodies, and hydroxyl group-containing compounds (A) of isocyanate group-containing compounds other than the aliphatic isocyanate (B1) and / or tolylene diisocyanate (B2). Modified bodies such as polymers can also be used. These can use 1 type, or 2 or more types.

  The content of the aliphatic isocyanate (B1) and / or tolylene diisocyanate (B2) in the isocyanate group-containing compound (B) in the present invention is preferably from the isocyanate group-containing compound (B) 100 in terms of heat resistance and moist heat resistance. 50 mass parts or more are preferable with respect to mass parts, and 60 mass parts or more are more preferable.

  The alicyclic polyisocyanate compound is not particularly limited. For example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3 -Bis (isocyanate methyl) cyclohexane etc. are mentioned. Of these, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate are preferable in terms of heat resistance, heat and humidity resistance, and yellowing resistance.

  The aromatic polyisocyanate compound other than the tolylene diisocyanate (B2) is not particularly limited. For example, 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.

  The acidic group-containing polyol (C) in the present invention is a polyol compound having at least one acidic group in the molecule. Although it does not specifically limit as an acidic group, For example, a carboxyl group, a sulfonyl group, a phosphoric acid group, a phenolic hydroxyl group etc. are mentioned. Among these, a carboxyl group is preferable from the viewpoints of emulsifying properties, coating film forming properties, drying properties, and water resistance.

  The acidic group-containing polyol compound (C) that can be used in the present invention is not particularly limited, and specifically, dimethylol alkanoic acid such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid, N , N-bishydroxyethylglycine, N, N-bishydroxyethylalanine, 3,4-dihydroxybutanesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid and the like. Among these, from the viewpoint of availability, an alkanoic acid having 4 to 12 carbon atoms (dimethylolalkanoic acid) containing two methylol groups is preferable, and 2,2-dimethylolpropionic acid is particularly preferable.

  In the present invention, the chain extender (D) is preferably a compound having in the molecule two or more active hydrogen atoms having reactivity with the isocyanate group of the polyurethane prepolymer (X). Examples of such chain extenders include polyamine compounds containing two or more primary or secondary amino groups in one molecule, hydrazide compounds, and low molecular weight polyol compounds having a molecular weight of less than 400. Polyamine compounds and hydrazide compounds include melamine, dimethylolurea, dimethylolethylamine, diethanolmethylamine, dipropanolethylamine, dibutanolmethylamine, hexylenediamine, tetraethylenepentamine, succinic dihydrazide, glutaric dihydrazide, adipic acid Dihydrazide, sebacic acid dihydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide, hydrazine, ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 2-methyl- 1,5-pentanediamine, diethylenetriamine, triethylenetetramine, 1,3-bis (aminomethyl) cyclohexane, piperazine, 2,5-dimethylpipera Emissions, diaminodiphenylmethane, tolylenediamine, xylylenediamine, isophoronediamine, hydrogenated diphenylmethane diamine, Bruno Ruboran diamine, polyamide polyamines and polyethylene polyimine and the like. Low molecular weight polyol compounds having a molecular weight of less than 400 include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3- Examples include cyclohexanedimethanol, trimethylolpropane, and pentaerythritol. A chain extender may be used individually by 1 type, and may be used in combination of 2 or more type. Of these, hydrazide compounds are preferred, and adipic acid dihydrazide is particularly preferred from the viewpoint of industrial availability, adhesion to the substrate, physical properties of the coating film, and durability.

  The amount of the chain extender (D) added is preferably equal to or less than the equivalent of an isocyanate group serving as a chain extension starting point in the obtained urethane polymer. If the addition amount of the chain extender (D) is not more than the equivalent of the isocyanate group, it is preferable from the viewpoints of heat resistance of the cured product, heat and humidity resistance, and adhesion to the substrate. Chain stretching can also be performed with water. In this case, water as a dispersion medium also serves as a chain extender.

  Content of the said chain extender (D) in this invention is 1-12 mass parts with respect to 100 mass parts of polyurethane resins (Y). Preferably it is 2-11 mass parts, More preferably, it is 3-10 mass parts. By being in these ranges, heat resistance, heat and humidity resistance, strength, elongation, flexibility, and low temperature characteristics are improved. In the present invention, chain extension can also be performed with water, but water is not included in the calculation of the content of the chain extender (D).

  The content of the isocyanate group-containing compound (B), the hydroxyl group-containing compound (A) and the acidic group-containing polyol (C) is appropriately determined depending on physical properties such as the hardness of the target cured product. ) And the active hydrogen of the acidic group-containing polyol (C), the isocyanate group of the isocyanate group-containing compound (B) is preferably 1.0 to 2.2 times equivalent, more preferably 1.2 to 2. 0 equivalents.

  In the present invention, the content of one or more (A1) selected from the group consisting of the polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol, and the content of the aliphatic isocyanate (B1) is relative to the active hydrogen of (A1). The isocyanate group of (B1) is preferably 1.5 to 3.5 times equivalent, more preferably 1.8 to 3.2 times equivalent. Within these ranges, it is preferable in terms of heat resistance, moist heat resistance, flexibility, and low temperature characteristics.

  In the present invention, the mass ratio of one or more (A1) selected from the group consisting of the polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol and the chain extender (D) is (A1) / (D) = 3 to 3. 20/1 is preferable, and 4 to 17/1 is more preferable. Within these ranges, it is preferable in terms of heat resistance, moist heat resistance, flexibility, and low temperature characteristics.

  In the present invention, the mass ratio of the aliphatic isocyanate (B1) and the chain extender (D) is preferably (B1) / (D) = 2-15 / 1, more preferably 3-12 / 1. These ranges are preferable in terms of heat resistance and moist heat resistance.

  In the present invention, the acid value of (X) is preferably 5 to 40 (mgKOH / g), more preferably 8 to 35 (mgKOH / g). Within these ranges, emulsification is easy to perform and it is preferable from the viewpoint of heat and humidity resistance of the coating film. The acid value is calculated by the method described in the examples.

  In order to disperse the polyurethane prepolymer (X) in water, a basic component may be added to the urethane prepolymer solution to neutralize acidic groups derived from the acidic group-containing polyol compound (C) contained in the polyurethane prepolymer. it can. Examples of basic components that can be used for neutralization include trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, dimethylethanolamine, diethylethanolamine, and N-methylmorpholine. , Organic amines such as pyridine, inorganic alkalis such as sodium hydroxide and potassium hydroxide, ammonia and the like. Among them, preferred is an organic amine, and particularly preferred is triethylamine. The addition method is preferably a method in which the basic component is added directly or as an aqueous solution to the polyurethane prepolymer solution, and the addition amount is 0.3 to 2 times equivalent to the acidic groups in the polyurethane prepolymer. 0.4 to 1.5 times equivalent is preferable.

  The polyurethane resin content in the aqueous polyurethane resin composition of the present invention is not particularly limited, but is preferably 20 to 65% by weight and more preferably 25 to 55% by weight from the viewpoints of emulsifiability and drying properties.

  Although it does not specifically limit as a manufacturing method of the water-based polyurethane resin composition of this invention, For example, a hydroxyl group containing compound (A) and an isocyanate group containing compound (B) are made to react in the organic solvent which does not have an active hydrogen group. After synthesizing an isocyanate-terminated urethane prepolymer (X), an organic solvent solution containing a polyurethane resin (Y) is obtained by adding an acidic group-containing polyol (C), and water is added to the organic solvent solution and dispersed in water. And a method of separating the organic solvent from the obtained aqueous composition. In this method, it is preferable that the chain extender (D) is added simultaneously with the addition of the water. Moreover, the prepolymer (X) can also be synthesized without using an organic solvent. When the prepolymer (X) is dispersed in water, a surfactant may be used as necessary.

  In the water-based polyurethane resin composition of the present invention, the filler, flame retardant, antifoaming agent, antibacterial agent, rust inhibitor, stabilizer, plasticizer, thickener, Additives such as glazes and other aqueous dispersion resins can be included.

  The antifoaming agent in the present invention is not particularly limited. From the viewpoint of the defoaming effect for the present invention, a silicone emulsion containing octamethylcyclotetrasiloxane is preferred. Although content of the silicone emulsion in a water-based polyurethane resin composition is not specifically limited, 0.001-2 weight% is preferable with respect to a polyurethane resin (Y), and 0.003-1 weight% is still more preferable.

  Although it does not specifically limit as a rust preventive agent in this invention, For example, a triazole compound is mentioned. The triazole compound is not particularly limited as long as it is a compound having a triazole group and a derivative thereof. For example, 1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4- Examples include triazole, 3-mercapto-1,2,4-triazole, 5-amino-3-mercapto-1,2,4-triazole, 1,2,3-triazole, 1H-benzotriazole and the like. Among these, 1,2,3-triazole is preferable from the viewpoint of the antirust effect on the present invention. Although content of the triazole compound in an aqueous polyurethane resin composition is not specifically limited, 0.001-2 weight% is preferable with respect to a polyurethane resin (Y), and 0.003-1 weight% is still more preferable.

  Although it does not specifically limit as an antifungal agent in this invention, For example, a benzimidazole compound is mentioned. The benzimidazole compound is not particularly limited as long as it is a compound having a benzimidazole group and a derivative thereof. For example, 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, 1- (butylcarbamoyl) Examples include methyl-2-benzimidazole carbamate, 2-methoxycarbonylaminobenzimidazole, 2- (4-thiazolyl) -benzimidazole, and 2-methoxycarbonylaminobenzimidazole. Among these, 2- (4-thiazolyl) -benzimidazole is preferable from the viewpoint of the antifungal effect on the present invention. Although content of the benzimidazole compound in an aqueous polyurethane resin composition is not specifically limited, 0.001-2 weight% is preferable with respect to a polyurethane resin (Y), and 0.002-1 weight% is still more preferable.

The heat resistance of the present invention is that the water dispersion is poured into a Teflon (registered trademark) container with a thickness of 100 μm wet (state of water dispersion), left at 25 ° C. and 65% RH for 24 hours, and then at 80 ° C. for 24 hours. When the surface resistance is measured after treating the test piece obtained by drying at 120 ° C. for 3000 hours, it is preferably 10 ¹¹ Ω or more.

The heat-and-moisture resistance of the present invention is that the water dispersion is poured into a Teflon (registered trademark) container with a thickness of 100 μm wet (state of water dispersion), left at 25 ° C. and 65% RH for 24 hours, and then 80 ° C. for 24 hours. When the surface resistance is measured after treating the test piece obtained by drying at 85 ° C. × 85% RH × 3000 hours, it is preferably 10 ¹¹ Ω or more.

In the drying property of the present invention, the water dispersion was poured into a Teflon (registered trademark) container with a thickness of 100 μm (wet state of the water dispersion), left at 25 ° C. and 65% RH for 24 hours, and then the surface resistance was measured. Is preferably 10 ¹³ Ω or more. If it is these ranges, workability | operativity will be favorable.

  Hereinafter, the polyurethane resin composition of the present invention and the polyurethane resin raw material composition of the present invention will be described in detail based on Examples and Comparative Examples. In the present specification, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified.

Example 1
To a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube, polybutadiene polyol (Poly bd R-15HT) is added as the A1 component, isophorone diisocyanate and methyl ethyl ketone are added as the B1 component. By reacting for a period of time, an MEK solution containing 30% of a prepolymer was obtained. Further, dimethylolpropionic acid, triethylamine, Neostan U-28 and methyl ethyl ketone were added as component C and reacted at 75 ° C. for 1 hour to obtain a MEK solution containing 50% prepolymer. Next, this solution was cooled to 45 ° C., followed by mixing emulsified water and adipic acid dihydrazide as component D. This emulsified dispersion was depressurized at 50 ° C. and 3 torr for 2 hours to remove the solvent. Finally, FS Antifoam 013A, 1,2,3-benzotriazole and Hoxster 25% sol were added, and (Y) contained An aqueous polyurethane resin composition having an amount of 40% by mass was obtained.

(Examples 2 to 13, Comparative Examples 1 to 4)
The composition and content described in Table 1 were adjusted by the method described in Example 1.
The raw materials used in Tables 1 and 2 are as follows.
(A1-1) Polybutadiene polyol, Poly bd R-15HT, molecular weight 1200, hydroxyl value 102.7 (mgKOH / g) (manufactured by Idemitsu Kosan)
(A1-2) Polybutadiene polyol, Poly bd R-45HT, molecular weight 2800, hydroxyl value 46.6 (mgKOH / g) (manufactured by Idemitsu Kosan)
(A1-3) Hydrogenated polybutadiene polyol, GI-1000, molecular weight 1500, hydroxyl value 67.5 (mgKOH / g) (manufactured by Nippon Soda)
(A1-4) Polyisoprene polyol, Poly ip, molecular weight 2500, hydroxyl value 46.6 (mgKOH / g) (manufactured by Idemitsu Kosan)
(A1-5) Hydrogenated polyisoprene polyol, Epol, molecular weight 2500, hydroxyl value 50.5 (mgKOH / g) (manufactured by Idemitsu Kosan)
(A2-1) Adipic acid, polyester polyol of 1,4-butanediol, Teslac 2464, molecular weight 1000, hydroxyl value 112 (mgKOH / g) (manufactured by Hitachi Chemical)
(B1-1) Isophorone diisocyanate (B2-1) 2,4-TDI, 8: 2 mixture of 2,6-TDI, Coronate T-80, (manufactured by Nippon Polyurethane Industry)
(B3-1) 4,4′-diphenylmethane diisocyanate (C1) dimethylolpropionic acid (D1) adipic acid dihydrazide (E1) triethylamine (E2) stanas octoate, Neostan U-28 (manufactured by Nitto Kasei Kogyo)
(F) Water (G1) Silicone-based antifoaming agent, FS Antifoam 013A (manufactured by Toray Dow Corning)
(G2) 1,2,3-benzotriazole (G3) 2- (4-thiazolyl) benzimidazole, Hoxter 25% sol (manufactured by Hokuko Chemical)

<Acid value>
The number of mg of KOH required to neutralize the free carboxyl group contained in 1 g of urethane prepolymer (X) is shown and calculated from the charged amount of acidic group-containing polyol (dimethylolpropionic acid (C1) used).

<Evaluation method>
(Heat resistance, heat and humidity resistance)
1. Preparation of test piece The water dispersion was poured into a Teflon (registered trademark) container with a thickness of 100 μm wet (state of water dispersion), left at 25 ° C. and 65% RH for 24 hours, and then dried at 80 ° C. for 24 hours. Obtained.
2. Evaluation of heat resistance After the test piece was treated at 120 ° C for 3000 hours, the surface resistance was measured and evaluated by the following method. In the examples, the surface resistance is ULTRA HIGH RESISTANCE METER R8340A manufactured by ADVANTEST, and a measurement voltage of 500 V is applied to a test piece (70 mm × 70 mm) at 25 ± 5 ° C. and 65 ± 5% RH for 60 seconds. This was done by measuring the later values.
○: Surface resistance of 10 ¹¹ Ω or more ×: Surface resistance of less than 10 ¹¹ Ω Evaluation of wet heat resistance After the test piece was treated at 85 ° C. × 85% RH × 3000 hours, the surface resistance was measured by the method described above.
○: Surface resistance of 10 ¹¹ Ω or more ×: Surface resistance of less than 10 ¹¹ Ω

(Drying)
The aqueous dispersion was poured into a Teflon (registered trademark) container with a thickness of 100 μm wet (in the state of an aqueous dispersion) and allowed to stand at 25 ° C. and 65% RH for 24 hours, and then the surface resistance was measured by the method described above.
○: Surface resistance of 10 ¹³ Ω or more ×: Surface resistance of less than 10 ¹³ Ω

<Evaluation results>
As can be seen from Examples 1 to 12, the water-based polyurethane resin composition of the present invention is excellent in heat resistance, moist heat resistance and drying properties.

  On the other hand, in a system with a small amount of (A1) as in Comparative Example 1 and a system with a large content of (D) as in Comparative Example 3, the heat and moisture resistance is poor. A system that does not contain (B1) and / or (B2) as in Comparative Example 2 and a system that has a low (C) content and a low acid value as in Comparative Example 4 cannot be emulsified, and performance Could not be evaluated.

  The water-based polyurethane resin composition of the present invention is an electronic used in switch parts and electric tools for electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, etc. Sealant for sealing the circuit to protect it from moisture and moisture, sealing agent and coating agent for electric and electronic devices, and capacitors, converters, transformers, electric wires, coils, electrical components (electronic components for automobiles) It is suitably used as an insulating material.

Claims (5)

A urethane prepolymer (X) obtained by reacting a hydroxyl group-containing compound (A) (wherein (A) does not contain an acidic group) , an isocyanate group-containing compound (B) and an acidic group-containing polyol (C ) , (X ) reacted further chain extension agent reactive with the isocyanate group (D) of the obtained, containing an aqueous dispersion of the polyurethane resin (Y), the sealing agent aqueous polyurethane resin composition of the electrical and electronic components Because
The hydroxyl group-containing compound (A) is one or more selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, and hydrogenated polyisoprene polyol (A1) with respect to 100 parts by mass of the hydroxyl group-containing compound (A). ) 80 parts by mass or more,
The isocyanate group-containing compound (B) contains isophorone diisocyanate and / or tolylene diisocyanate (B2),
The chain extender (D) contains adipic acid dihydrazide;
The content of the chain extender (D) is 1 to 12 parts by mass with respect to 100 parts by mass of the polyurethane resin (Y).
Sealant aqueous polyurethane resin composition of the electrical and electronic components. The hydroxyl group-containing compound (A) contains 95 parts by mass or more of one or more (A1) selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol with respect to 100 parts by mass of the hydroxyl group-containing compound (A). to claim 1 sealant aqueous polyurethane resin composition of the electric and electronic component according. When the acid value is 5 to 40 (mg KOH / g) in a claim 1 or 2 sealant aqueous polyurethane resin composition of the electric and electronic component according to (X). Furthermore , the water-based polyurethane resin composition for sealing agents of the electrical / electronic components in any one of Claims 1-3 containing a triazole compound and / or a benzimidazole compound. The electrical / electronic component which has the dried material of the water-based polyurethane resin composition for sealing agents of the electrical / electronic component in any one of Claims 1-4 in a sealing part .