JP2006045484A - Two-pack reactive polyurethane type electrical insulating coating and polyurethane type insulated wire using the coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane type electrical insulating coating which reduces the amount of an organic solvent to be used and of which the viscosity variation after mixing two liquids is relatively small and to provide a polyurethane type insulated wire that reduces the remaining amount of an organic solvent. <P>SOLUTION: The two-pack reactive polyurethane type electrical insulating coating is comprised of an isocyanate group-containing compound (a) and an active hydrogen-containing compound (b). The viscosity increasing ratio (=viscosity of one hour after mixing the two liquids/viscosity immediately after mixing the two liquids) when combining the isocyanate group-containing compound (a) with the active hydrogen-containing compound (b) is 50 or less. The polyurethane type insulated wire is formed by applying the two-pack reactive polyurethane type electrical insulating coating to a conductor directly or through other insulated layer and baking the same to form the insulated layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  INDUSTRIAL APPLICABILITY The present invention relates to a polyurethane-based insulated wire with reduced residual organic solvent harmful to the environment and the human body, and a two-component reaction type with little viscosity change (after two-component mixing) used for forming an insulating layer of this insulated wire. The present invention relates to a polyurethane-based electrical insulating paint.

Polyurethane enameled wire insulation paint is applied and baked on electrical conductors (conductors) such as copper wires and aluminum wires to form polyurethane electrical insulation films on the conductors, and is widely used as electrical insulated wires for electrical and electronic equipment. in use. Many insulating coatings for polyurethane enamel wires have a resin concentration of about 10 to 50%, and the remainder consists of an organic solvent mainly composed of phenol, cresol, xylenolic acid, etc., and a mixture of xylene, solvent naphtha, etc. as a diluent. Yes. However, these organic solvents do not contribute to the formation of an insulating film. For example, a large amount of organic solvent is applied in the process of heating and baking to form an insulating layer by applying to a conductor and passing through a wire baking furnace. Evaporate. This evaporated organic solvent is usually subjected to combustion treatment using a combustion catalyst, etc., but this heating evaporation and combustion treatment consumes a large amount of energy, and the combustion catalyst is also expensive and expensive. ineffective. In addition, carbon dioxide gas, nitrogen oxide gas, and partly unburned solvent are released into the atmosphere through combustion treatment, resulting in environmental pollution such as global warming, air pollution, water pollution, etc. It is a major problem in terms of safety and hygiene such as harmfulness of the environment and deterioration of the working environment, and it is required to reduce the amount of organic solvent used as much as possible. Moreover, since these organic solvents are expensive, there is also a problem that the resin solution becomes expensive due to the use of a large amount of the organic solvent. In recent years, due to increasing interest in the environment, such as global warming phenomenon and substances that adversely affect the environment, activities to reduce environmentally hazardous substances have been actively conducted. Various proposals have been made to reduce the amount of organic solvents used in insulating coatings and to change to alternative substances that have less influence on the environment (see, for example, Patent Documents 1 and 2).
In addition, conventional insulation coatings for polyurethane enamel wires are blocked organic polyisocyanate compounds and polyols that are stabilized by masking (blocking) the isocyanate groups of organic polyisocyanates with phenols such as phenol, cresol, and xylenolic acid. However, the block organic polyisocyanate compound and the active hydrogen-containing prepolymer are high in viscosity because they are used as an insulating paint. A large amount of organic solvent is used to improve the coating workability, and the highly toxic phenols used to stabilize the isocyanate groups are completely dissociated even when heated to a high temperature during baking. Will not dissipate and a significant amount will remain in the insulation film. So-called residual solvent amount is a problem that high. Phenols remaining in this insulating layer are gradually released into the environment such as indoors while using electrical appliances and electronic devices, etc., and are exposed to users, resulting in health damage, air pollution and It becomes an environmentally hazardous substance that contributes to the deterioration of the working environment.
Two-component polyurethane insulation paints have also been proposed, but when coating and baking, when an organic polyisocyanate solution and an active hydrogen-containing prepolymer are mixed, the viscosity rises in a short time, making it difficult to coat the conductor. There was an inconvenience.

JP 58-133876 A Japanese Patent Laid-Open No. 04-11676

  An object of the present invention is to provide a polyurethane-based electrical insulating paint that uses a small amount of an organic solvent and has a relatively small change in viscosity after mixing two liquids, in order to solve the above-mentioned problems of the prior art. An object of the present invention is to provide a polyurethane-based insulated wire using this electrically insulating paint and having a reduced amount of organic solvent remaining.

  As a result of intensive studies in view of the above problems, the present inventors divided the insulating paint into a solution (A) containing an isocyanate group and a solution (B) containing active hydrogen, and used a specific isocyanate compound in the solution (A). Thus, the viscosity increase ratio after mixing the solution A and the solution B can be reduced to a specific value or less, and the insulating coating satisfying this has a small viscosity change, good application and baking workability, and an organic solvent. The present invention has been completed by finding that an excellent polyurethane-based electrical insulating paint with a small amount of use can be obtained, and that a polyurethane-based insulated wire with an extremely small amount of organic solvent remaining in the film after baking can be obtained.

That is, the present invention includes the following (1) to (6).
(1) A two-component reactive polyurethane-based electrically insulating paint comprising (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound, wherein (a) the isocyanate group-containing compound and (b) the active hydrogen in a pot life test Ratio of increase in viscosity when mixed with compound (= viscosity after 1 hour of 2 liquid mixing / viscosity immediately after mixing of 2 liquid) is 50 or less. paint.

(2) The above (1), wherein the (a) isocyanate group-containing compound is an isocyanate group-containing urethane prepolymer obtained by reacting an organic polyisocyanate and a polyol compound with an isocyanate group in excess of a hydroxyl group. Two-component reactive polyurethane-based electrically insulating paint.

(3) The two-component reactive polyurethane electrical insulating paint according to (2), wherein the organic polyisocyanate is an aromatic polyisocyanate.

(4) The two-component reactive polyurethane electrical insulating paint according to (3), wherein the aromatic polyisocyanate is diphenylmethane diisocyanate containing at least 2,4′-diphenylmethane diisocyanate.

(5) The two-component reactive polyurethane-based electrically insulating paint according to any one of (1) to (4) above is applied directly or via another insulating layer on a conductor and baked to form an insulating layer. Polyurethane insulated wire.

(6) The polyurethane-based insulated wire according to (5), wherein the insulating layer is an insulating layer containing no phenols as a residual solvent.

  According to the present invention, there is provided a polyurethane-based electrical insulating paint that uses a small amount of organic solvent and has a relatively small viscosity change after mixing two liquids, and reduces the residual amount of organic solvent using this electrical insulating paint. A polyurethane-based insulated electric wire can be provided. Therefore, the polyurethane-based electrical insulating paint of the present invention prevents wasteful release of the organic solvent into the atmosphere, and is economical as well as the global environment and safety and health. Further, when producing a polyurethane insulated wire using this electrical insulating paint, it is easy to mix and apply the paint, and the energy efficiency for baking and the like is remarkably improved.

The present invention is described in detail below.
The two-component reactive polyurethane electrical insulating paint of the present invention comprises (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound. First, (a) the isocyanate group-containing compound in the present invention will be described. .
(A) Although an organic polyisocyanate can be used as the isocyanate group-containing compound, an isocyanate group-containing urethane prepolymer obtained by reacting an organic polyisocyanate and a polyol compound under an excess of isocyanate groups with respect to a hydroxyl group. Polymers are preferred.

Examples of the organic polyisocyanate include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, or mixtures thereof, such as diphenylmethane diisocyanates, 2,4-toluene diisocyanate, Toluene diisocyanates such as 2,6-toluene diisocyanate or mixtures thereof, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, 1, , 2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene Diisocyanates, aromatic diisocyanates such as 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene Examples include alicyclic diisocyanates such as araliphatic diisocyanates such as diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate. In addition, so-called modified isocyanates such as adduct-modified products, burette-modified products, isocyanurate-modified products, uretonimine-modified products, uretdione-modified products, and carbodiimide-modified products of these organic diisocyanates are also included. Furthermore, polyisocyanates called so-called polymeric bodies such as polymethylene polyphenyl polyisocyanate, crude toluene polyisocyanate and the like are also included.
These can be used alone or in admixture of two or more.
Among these, the aromatic polyisocyanate has a long pot life when mixed with an active hydrogen-containing compound (b) described later, with good solderability and heat resistance of the obtained polyurethane-based insulated wire. Diphenylmethane diisocyanates such as 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate or a mixture of any two or more thereof are preferred, and 2,4′- Diphenylmethane diisocyanates (mixtures) containing at least diphenylmethane diisocyanate (for example, a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate) are preferred.

Examples of the polyol compound include low molecular polyols having a number average molecular weight of 1,000 or less, and low molecules having a number average molecular weight of 500 or less, from the viewpoint of good storage stability and coating baking workability of the resulting polyurethane-based electrical insulating coating. Polyols are preferred. Specifically, for example, ethylene glycol, 1,2-propanediol, 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, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, Ethylene oxide or propylene oxide adduct of bisphenol A, trimethylolpropane, glycerin, pentaerythritol, polyester polyol, polycarbonate polyol, and hydrocarbon polyol listed as (b) active hydrogen-containing compounds described later have a number average molecular weight of 1. 000 like the following low molecular weight.
Of these, trimethylolpropane, glycerin, and pentaerythritol are preferred, and trimethylolpropane is particularly preferred because the viscosity of the resulting isocyanate group-containing urethane prepolymer is low.
For modification of the isocyanate group-containing urethane prepolymer, polyols such as polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene glycol, polybutadiene polyol, polyisobutylene polyol, etc. having a number average molecular weight exceeding 1,000 are used. You can also.
Any of these may be used alone or in admixture of two or more.

In the reaction between the organic polyisocyanate and the polyol compound, the equivalent ratio of isocyanate group to hydroxyl group is preferably isocyanate group / hydroxyl group = 1.1 / 1 to 10/1, more preferably 1.8 / 1 to 5/1.
The isocyanate content of the isocyanate group-containing urethane prepolymer is preferably 1 to 30% by mass and more preferably 5 to 25% by mass in terms of solid content of 100% by mass.

Examples of the method for producing an isocyanate group-containing urethane prepolymer include a method in which the organic polyisocyanate and the polyol compound are reacted by heating to, for example, 50 to 200 ° C.
In this reaction, a metal organic material such as zinc octylate and a tertiary amine such as triethylamine, which are known in the production of polyurethane and polyurea, can be used as a catalyst for promoting the reaction, if necessary.
In addition, in the production of this isocyanate group-containing urethane prepolymer, it can be reacted without using a solvent, and in order to facilitate the production, an aliphatic solvent such as n-hexane, an alicyclic solvent such as cyclohexane, Reacts with known isocyanate groups such as aromatic solvents such as xylene, ester solvents such as methyl 1,3-butylene glycol acetate, ketone solvents such as methyl isobutyl ketone, petroleum fraction solvents such as kerosene and industrial gasoline It is also possible to carry out the reaction in the presence of a non-organic solvent. If the non-volatile content is low, the economy is adversely affected, and the residual solvent in the insulating film formed after the insulating coating is applied to the conductor and baked increases.
As an apparatus for producing this isocyanate group-containing urethane prepolymer, any apparatus can be used as long as the above reaction can be achieved, for example, a mixing and kneading apparatus such as a reaction kettle with a stirrer, a kneader, or a uniaxial or multiaxial extrusion reactor. It is done.

Specific examples of the (b) active hydrogen-containing compound in the present invention include polymer polyols, low-molecular polyols, low-molecular polyamines, low-molecular amino alcohols, etc. Among these, polymer polyols Are preferred.
Specific examples of the polymer polyols include polyester polyols, polyimide polyester polyols, polyurethane polyols, polyether polyols, polycarbonate polyols, hydrocarbon polyols, poly (meth) acrylic polyols, animal and plant polyols, and copolyols thereof. Among these, polyester polyol is preferable.
These can be used alone or in admixture of two or more.

Examples of the polyester polyol include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, and naphthalene dicarboxylic acid. One kind of carboxylic acid or carboxylic acid derivative such as polycarboxylic acid such as acid or trimellitic acid, or low molecular alkyl ester such as methyl ester or ethyl ester of such polycarboxylic acid, or polycarboxylic acid derivative such as acid anhydride As described above, as an alcohol component, low molecular polyols having a number average molecular weight of 1,000 or less, polyoxyethylene glycol, polyoxypropylene glycol used as a polyol compound in the production of the isocyanate group-containing urethane prepolymer One or more types of polyols such as polymer polyols having a number average molecular weight exceeding 1,000 such as polyoxytetramethylene glycol, polybutadiene polyol, polyisobutylene polyol, etc., without using a catalyst or using a metal-based substance as a reaction catalyst Polyester polyols obtained by hydration reactions (including transesterification reactions), low molecular weight polyamines such as hexamethylenediamine, xylylenediamine, isophoronediamine, monoethanolamine, diethanolamine, etc. in addition to the acid and alcohol components described above There may also be mentioned polyester polyols containing amide bonds such as ester amide polyols obtained by reacting one or more of low molecular amino alcohols.
As the acid component and alcohol component, monocarboxylic acids such as n-stearic acid and stearyl alcohol, monoalcohols, and the like can be used for modifying the polyester polyol.
Also, for example, a lactone system obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone using these low molecular polyols, low molecular polyamines, and low molecular amino alcohols as initiators. Polyester polyols are also included.
Of the acid component and the alcohol component, a polycarboxylic acid and / or a polycarboxylic acid derivative is preferable as the acid component, and the alcohol component has a number average molecular weight of 1 in terms of good heat resistance of the obtained polyurethane insulated wire. 1,000 or less low molecular polyols are preferred.

In the production of the polyester polyol, the esterification reaction between the alcohol component and the total acid component is preferably carried out under the condition of excess of alcoholic hydroxyl group with respect to the carboxyl group (including the carboxyl group from the carboxylic acid derivative). This is because a hydroxyl group remains in the molecular chain of the compound having an ester bond in the molecule, and this is reacted with the isocyanate group of the (a) isocyanate group-containing compound during baking to generate a urethane bond.
In addition, from the viewpoint of coating and baking workability and solderability, the equivalent ratio of alcoholic hydroxyl group / carboxyl group (including carboxyl group from carboxylic acid derivative) is 1.2 / 1 to 5/1, more preferably 1.5 / It is preferable to make it react in the range of 1-3 / 1, especially 1.5 / 1-2.5 / 1.
The production of the polyester polyol is suitably carried out by heat-reacting the alcohol component and acid component in the absence of a catalyst or using a metal-based substance as an esterification reaction catalyst at a temperature of 100 to 250 ° C. Depending on the raw material used, a dehydration condensation reaction or a transesterification reaction occurs. As the reaction solvent, the same solvent as used in the production of the isocyanate group-containing urethane prepolymer can be used, and the organic solvent can be used as it is as the (b) active hydrogen-containing compound of the coating.
In the present invention, the metal-based substance that can be used as the esterification reaction catalyst means at least one selected from the group of metals, metal inorganic compounds, and metal organic compounds. , Metal magnesium, metal calcium, metal barium, metal titanium, metal zirconium, metal manganese, metal iron, metal copper, metal zinc, metal lead, metal aluminum, metal silicon, metal tin, metal bismuth, etc., metal inorganic Examples of system compounds include oxides, hydroxides, chlorides, carbonates, and the like of the above-mentioned various metals such as zinc oxide, aluminum oxide, aluminum hydroxide, titanium trichloride, and magnesium carbonate. As for the above-mentioned various metals such as aluminum tri-sec-butoxide, tetra-n-butyl titanate (TBT), etc. Chelate compounds of various metals such as xoxide, aluminum tris (acetylacetonate), titanium tetra (acetylacetonate), magnesium acetate, barium octylate, manganese acetate, lead acetate, zinc octylate, lead octylate, octylic acid Examples thereof include salts of the various metals such as zirconium, zinc naphthenate and lead naphthenate with organic acids, and salts of the organic metals and organic acids of the various metals such as dibutyltitanium dilaurate.
These can be used alone or in admixture of two or more.
Among these, in terms of low toxicity and good handleability, metal organic compounds are preferable, and further in terms of maintaining the performance of the resulting polyurethane-based insulated wire, with excellent esterification reaction promoting effects. An organic compound of titanium and an organic compound of manganese are preferable, and tetra-n-butyl titanate (TBT) and manganese acetate are particularly preferable. In addition, it is preferable not to use metallic lead and a lead compound for environmental load reduction.
The amount of the esterification reaction catalyst used is preferably 0 to 10 parts by mass and more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the total of the acid components. When it exceeds 10 mass parts, when it mixes with (a) isocyanate group containing compound, the reaction delay effect will be worsened.

The polyimide polyester polyol is composed of an alcohol component, an imide bond-containing polycarboxylic acid and / or an imide bond-containing polycarboxylic acid derivative (an ester of an imide bond-containing polycarboxylic acid, an acid anhydride, etc.), and / or It can be obtained by reacting an imide bond-containing carboxylic acid derivative with a carboxylic acid and / or a carboxylic acid derivative as required.
Examples of the alcohol component include those similar to the alcohol component used in the production of the polyester polyol. However, the polyol is preferable in terms of good heat resistance after baking, and the number average molecular weight is more preferable. 1,000 or less low molecular polyols are preferred.
Examples of the imide bond-containing carboxylic acid include those obtained by reacting 2 mol of trimellitic anhydride with 1 mol of diamine. In this case, an acid component used for the production of the polyester polyol can be used in combination. Examples of the diamine include 4,4′-diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, 1,4-diaminonaphthalene, 4,4′-diaminodiphenyl ether, hexamethylenediamine, diaminodiphenylsulfone, and the like. These can be used alone or in admixture of two or more.
As carboxylic acid or a carboxylic acid derivative, what is used for manufacture of the said polyester polyol is mentioned, for example, These can also be used individually or in combination of 2 or more types.
Among these polyimide polyester polyols, a polyimide polyester polyol obtained from a polyol and an imide bond-containing polycarboxylic acid and / or an imide bond-containing polycarboxylic acid derivative is preferable in that the heat resistance of the obtained polyurethane-based insulated wire is favorable. .

  As the polyurethane polyol, one or more compounds similar to those exemplified as the alcohol component used in the production of the polyester polyol, and one or more compounds similar to those exemplified as the organic polyisocyanate are used as isocyanate. Examples thereof include those in which an alcoholic hydroxyl group remains in a molecular chain obtained by reacting a group with a hydroxyl group-excess condition.

  Examples of the polycarbonate polyol include a dehydrochlorination reaction between low molecular polyols and phosgene used in the production of the polyester polyol, or transesterification of the low molecular polyols with diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and the like. What is obtained by reaction is mentioned.

  Examples of polyether polyols include ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran and the like using low molecular polyols, low molecular polyamines, and low molecular amino alcohols used in the production of the polyester polyol as initiators. Examples thereof include polyoxyethylene polyol, polyoxypropylene polyol, polytetramethylene ether polyol, polyether polyol obtained by copolymerization thereof, and polyester ether polyol using the polyester polyol and polycarbonate polyol as an initiator. In addition, polyoxyalkylene monools obtained by ring-opening polymerization of epoxides such as propylene oxide using monoalcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol as initiators are also used for modification of polyester polyol and polyimide polyester polyol. it can.

  Examples of the hydrocarbon-based polyol include polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and polyalkylene polyols such as hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol.

  Examples of the poly (meth) acrylic polyol include 1 (meth) acrylic acid ester-based compounds containing a hydroxyl group such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and hydroxypropyl methacrylate. A known radical polymerization method such as batch polymerization or continuous polymerization of at least one monomer and at least one other ethylenically unsaturated compound in the presence or absence of a radical polymerization initiator or a solvent. Can be obtained by reaction.

  Examples of animal and plant polyols include castor oil-based diols.

The number average molecular weight of these (b) active hydrogen-containing compounds in terms of polystyrene by gel permeation chromatography is preferably 150 to 30,000, more preferably 200 to 10,000, and particularly preferably 300 to 5,000, and the hydroxyl value (KOHmg / g) is preferably 5 to 1,000, more preferably 100 to 800, and particularly preferably 150 to 500. When the number average molecular weight exceeds 30,000, or when the hydroxyl value is less than 5, the viscosity of the resulting polyurethane-based electrical insulating paint is increased and coating baking workability is deteriorated. When the number average molecular weight is less than 150, Or when the hydroxyl value exceeds 1,000, the polyurethane-based film after coating and baking becomes brittle.
In the present invention, the organic solvent may be used so as to have a predetermined nonvolatile content in the synthesis of (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound. May be manufactured at a high concentration, the other may be manufactured at a low concentration, and the two may be mixed so that a predetermined nonvolatile content is obtained. Alternatively, either one or both may be manufactured at a high concentration, and an organic solvent may be added after the manufacturing or at the time of mixing to obtain a predetermined nonvolatile content. Which method should be adopted may be selected as appropriate in consideration of ease of manufacture and ease of storage.
The amount of organic solvent used in the present invention is non-volatile when (a) an isocyanate group-containing compound and (b) an active hydrogen group-containing compound are mixed in terms of preventing environmental pollution and reducing residual solvent in the insulating layer. It is preferable to use so that a content may be 60 mass% or more.

The two-component reactive polyurethane-based electrical insulating paint of the present invention includes, for example, a curing accelerating catalyst as an additive other than an organic solvent in one or both of (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound. , Natural wax, mineral oil wax, higher fatty acids and derivatives thereof, lubricity imparting agents such as lubricating resin fine particles, physical property improving agents such as polyvinyl formal, polyamide, epoxy resin, and various colorants such as dyes and pigments can do. In the present invention, it is better not to use a curing accelerating catalyst in order to suppress an increase in viscosity after mixing two liquids, but it can be used within a range that does not impair the object of the present invention.
In the present invention, the curing accelerating catalyst should not be used in order to suppress an increase in viscosity after mixing the two liquids, but can be used within a range not impairing the object of the present invention. Examples of the curing accelerating catalyst include metal materials similar to those exemplified as the esterification reaction catalyst of the polyester polyol, triethylamine, tetramethylethylenediamine, 1,8-diazabicyclo- (5,4,0) undecene-7. And tertiary amines such as (DBU) and salts of various acidic compounds such as octylate, oleate, formate, and p-toluenesulfonate of these tertiary amines. As for the curing accelerating catalyst, it is preferable not to use metallic lead or a lead compound in order to reduce environmental load.

Any conventionally known method can be adopted as the method for producing the polyurethane insulated wire of the present invention. Specifically, for example, after mixing (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound of a two-component reactive polyurethane electrical insulating paint, or while mixing, a direct or other insulating layer is formed on the conductor. Then, it is applied by a felt drawing method, a die drawing method or the like, and continuously passed through one or more heating and baking furnaces at a temperature of 200 to 550 ° C., a plurality of times, preferably 10 times or less (10 By applying and baking to form a desired electrical insulation film (layer) by passing 5 times or less (less than 5 passes), more preferably 5 times or less, a polyurethane-based insulated wire can be obtained. The ratio of the increase in viscosity after mixing the two liquids is 50 or less, and more preferably 30 or less. However, if the ratio exceeds 50, a significant increase in viscosity occurs during the operation of applying and baking the paint, and the wire is stably and continuously It becomes difficult to produce. The mixing ratio of (a) the isocyanate group-containing compound and (b) the active hydrogen-containing compound is the same as the equivalent ratio of (a) the isocyanate group of the isocyanate group-containing compound and (b) the hydroxyl group of the active hydrogen-containing compound. The hydroxyl group is preferably 0.3 / 1 to 1.5 / 1, more preferably 0.5 / 1 to 1.3 / 1.
In the present invention, since no block polyisocyanate is used, the residual solvent in the insulating layer of the polyurethane insulated wire obtained by the above production method does not contain highly toxic phenols, and the amount of residual solvent A polyurethane-based insulated wire having a small amount, specifically, a residual solvent amount of 200 ppm or less, further 100 ppm or less, even more 50 ppm or less, and especially not contained at all can be suitably produced.
Note that the thickness of the coating with the two-component reactive polyurethane electrical insulating paint of the present invention, or the total thickness with other coatings, can be appropriately selected depending on the thickness of the conductor such as the copper wire used and the required performance. Good. When such a film thickness is not formed by one application and baking, the application and baking may be repeated as many times as necessary.
As a conductor, what is generally used as a conductor of an electric wire, such as copper, nickel plating copper, aluminum, gold | metal | money plating, can be mentioned, for example.
Other insulating layers are not particularly limited, but for example, polyvinyl formal-based, polyurethane-based, polyester-based, polyesterimide-based, polyesteramidoimide-based, polyhydantoin-based, polyamideimide-based, polyimide-based insulating film layers are suitable. Can be listed.

Hereinafter, the present invention will be described in more detail with reference to examples and the like.
Synthesis example 1
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and heating device, 1250 g of 4,4'-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry Co., Ltd.) and 150 g of trimethylolpropane (manufactured by Guangei Chemical Industry Co., Ltd.) are charged. The mixture was heated under a nitrogen stream and reacted at 80 ° C. for 2 hours. Thereafter, 300 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries) and 300 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added to the reaction vessel to dissolve the generated isocyanate group-containing urethane prepolymer, and NCO An isocyanate group-containing urethane prepolymer solution (a1) having a content of 20% by mass, a viscosity of 400 (mPa · s / 30 ° C.), and a nonvolatile content of 70% by mass was obtained.

Synthesis example 2
In the same reaction vessel as in Synthesis Example 1, 615 g of 4,4′-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry Co., Ltd.), a mixture of 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate (BASF Inoac Polyurethane) 650 g of lupranate MI) and 150 g of trimethylolpropane (manufactured by Guangei Chemical Industry Co., Ltd.) were charged, heated under a nitrogen stream, and reacted at 80 ° C. for 2 hours. Thereafter, 300 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries) and 300 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added to the reaction vessel to dissolve the generated isocyanate group-containing urethane prepolymer, and NCO An isocyanate group-containing urethane prepolymer solution (a2) having a content of 20% by mass, a viscosity of 300 (mPa · s / 30 ° C.), and a nonvolatile content of 70% by mass was obtained.

Synthesis example 3
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and condenser, 592 g of phthalic anhydride (manufactured by Mitsubishi Gas Chemical Company), 536 g of trimethylolpropane (manufactured by Koei Chemical Industry Co., Ltd.), 1,6-hexanediol (Ube Industries, Ltd.) 236g), heated in a nitrogen stream without using a catalyst and confirmed dissolution of the raw material at 130 ° C, and then heated to 200 ° C over 5 hours while removing water as a by-product from the system. The reaction was continued at 200 ° C. After the acid value of the contents became 5 KOH mg / g or less, a reduced pressure reaction was performed to complete the reaction. In a reaction vessel, 280 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries) and 277 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added and dissolved, OH value 368 (mg KOH / g), viscosity 2000 A polyester polyol solution having a non-volatile content of 70% by mass (mPa · s / 30 ° C.) was obtained.

Example 1
The two-component reactive polyurethane-based electrically insulating coating material A comprising the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and the polyester polyol solution obtained in Synthesis Example 3 is used as the isocyanate group-containing urethane prepolymer solution (a1). And the polyester polyol solution were mixed at a mass ratio of 1: 1 [equivalent ratio (isocyanate group of isocyanate group-containing urethane prepolymer / hydroxyl group of polyester polyol) = 0.75] and poured into a varnish bath.
The injected mixed solution was applied and baked on a 0.40 mmφ copper wire under the conditions shown below in 8 passes to produce a polyurethane electrically insulated wire having a film thickness of 25 μm. The insulated wire was manufactured for the following die arrangement.
[Coating and baking conditions]
(1) Dice arrangement 8 passes: 0.42 mmφ × 1, 0.43 mmφ × 2, 0.44 mmφ × 2, 0.45 mmφ × 2, 0.46 mmφ × 1
(2) Baking furnace: horizontal hot air circulation path (furnace length 3.3m)
(3) Furnace temperature: 420 ° C
(4) Line speed: 120 m / min

Example 2
The two-component reactive polyurethane-based electrically insulating coating material A comprising the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and the polyester polyol solution obtained in Synthesis Example 3 is used as the isocyanate group-containing urethane prepolymer solution (a1). And the polyester polyol solution were mixed at a mass ratio of 1: 1 [equivalent ratio (isocyanate group of isocyanate group-containing urethane prepolymer / hydroxyl group of polyester polyol) = 0.75] and poured into a varnish bath.
The injected mixed solution was applied and baked on a 0.40 mmφ copper wire in four passes under the conditions shown below to produce a polyurethane electrically insulated wire having a film thickness of 25 μm. The insulated wire was manufactured for the following die arrangement.
[Coating and baking conditions]
(1) Dice arrangement 4 passes: 0.44 mmφ × 1, 0.45 mmφ × 1, 0.46 mmφ × 1, 0.47 mmφ × 1
(2) Baking furnace: horizontal hot air circulation path (furnace length 3.3m)
(3) Furnace temperature: 420 ° C
(4) Line speed: 120 m / min

Example 3
In Example 1, instead of the isocyanate group-containing urethane prepolymer solution (a1), the isocyanate group-containing urethane prepolymer solution (a2) obtained in Synthesis Example 2 was used, and the two-component reaction type polyurethane electrical insulating paint B and A polyurethane-based electrically insulated wire having a film thickness of 25 μm was produced in the same manner except that.

Example 4
In Example 2, instead of the isocyanate group-containing urethane prepolymer solution (a1), using the isocyanate group-containing urethane prepolymer solution (a2) obtained in Synthesis Example 2, a two-component reactive polyurethane-based electrically insulating paint B and A polyurethane-based electrically insulated wire having a film thickness of 25 μm was produced in the same manner except that.

Comparative Example 1
In Example 1, instead of using the two-component reactive polyurethane-based electrical insulating paint A, one-component polyurethane-based electrically insulating coating APU-3147S (manufactured by Auto Chemical Industries, non-volatile content 47 mass%, viscosity 5500 mPa · s) / 30 ° C.), a polyurethane-based electrically insulated wire having a film thickness of 25 μm was produced in the same manner except that the coating was applied and baked in 8 passes with the following die arrangement.
Dice arrangement (8 passes): 0.43 mmφ × 1, 0.44 mmφ × 2, 0.45 mmφ × 2, 0.46 mmφ × 3

[Pot life test]
The pot life test of each of the two-component reactive polyurethane-based electrically insulating coatings A and B obtained in Examples 1 and 3 and APU-3147S, which is the one-component polyurethane-based coating material of Comparative Example 1, was performed according to the following procedure.
1) The isocyanate group-containing urethane prepolymer solution (a1 or a2) and the polyester polyol were individually put in a glass container and immersed in a controlled constant temperature water bath at 30 ° C. ± 1 ° C. for 1 hour to stabilize the viscosity.
2) The isocyanate group-containing urethane prepolymer solution (a1 or a2) whose viscosity was stabilized and the polyester polyol were weighed in the proportions as in Examples, and instantly mixed with a stirrer for 1 minute.
3) The obtained mixture was immediately put into a glass container and immersed in a controlled constant temperature water bath of 30 ° C. ± 1 ° C.
4) One minute after the completion of mixing, the viscosity was measured with a B-type viscometer (rotor No. 3, 6 to 60 rpm, 3 minutes later).
* Since the time required for reading the numerical value from the start of the B-type viscometer is 3 minutes, the total time required for the pot life measurement is 5 minutes from the start of mixing. This measurement end time was defined as the initial time (0 minutes) of the pot life test, and the viscosity was measured after 30 minutes and 60 minutes.
These test results are summarized in Table 1.

〔performance test〕
Using the polyurethane-based insulated wires produced in Examples 1 to 4 and Comparative Example 1, the softening resistance test, the dielectric breakdown voltage test, the solderability test, and the residual solvent measurement in the electrical insulating film were performed.
Softening resistance test:
JIS C3003: 1999 “Enamel wire test method” 11.2B method, b) According to the crossing method. The mass of the weight was tested with one type.
Dielectric breakdown voltage test:
JIS C3003: 1999 “Enamelled wire test method” 10.2B method, b) According to two methods.
Solderability:
According to JIS C3003: 1999 “Enamel wire test method” 14.2B method.
Non-volatile measurement:
JIS C2351: 1994 "varnish for enameled wire" 7.3 Nonvolatile content test.
Residual solvent measurement in electrical insulation film:
5 g of the obtained polyurethane-based electrically insulated wire was weighed and placed in a container that can be sealed (the one used this time is a 25 cm ³ vial with an aluminum cap). This container was heated at 150 ° C. for 60 minutes.
Residual solvent generated from the electrical insulating film by heating was measured by gas chromatography.
* The gas chromatograph used this time is GC-14B made by Shimadzu Corporation, and the measurement conditions are HR-1701 column made by Shimadzu Corporation, carrier gas helium, flow rate 40 ml / min, detector FID, injection 180 ° C., start temperature 45 ° C. The temperature rate is 5 ° C./min, and the final temperature is 160 ° C.
Residual solvent amount (ppm) = measured by GC (μg) / film mass (g)
Film mass = wire mass (g) × (film adhesion rate / 100)
Coating rate (%) = 1.3π (D ₂ ² −D ₁ ² ) / [8.89πD ₁ ² + 1.3π (D ₂ ² −D ₁ ² )] × 100
D ₁ : Conductor diameter D ₂ : Electric wire outer diameter From the obtained measurement results, the residual solvent concentration in the polyurethane electrical insulating film was determined.
The raw material composition and the performance test results are summarized in Table 2.

Claims (6)

A two-component reactive polyurethane-based electrical insulating paint comprising (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound,
In the pot life test, the ratio of increase in viscosity when (a) an isocyanate group-containing compound and (b) an active hydrogen-containing compound are mixed (= viscosity after 1 hour of 2 liquid mixing / viscosity immediately after 2 liquid mixing) is 50 or less. The two-component reactive polyurethane-based electrically insulating paint, characterized in that   2. The isocyanate group-containing urethane prepolymer (2) according to claim 1, wherein the (a) isocyanate group-containing compound is an isocyanate group-containing urethane prepolymer obtained by reacting an organic polyisocyanate and a polyol compound with an isocyanate group-excess condition with respect to a hydroxyl group. Liquid-reactive polyurethane electrical insulating paint.   The two-component reactive polyurethane-based electrically insulating paint according to claim 2, wherein the organic polyisocyanate is an aromatic polyisocyanate.   The two-component reaction type polyurethane electrical insulating paint according to claim 3, wherein the aromatic polyisocyanate is diphenylmethane diisocyanate containing at least 2,4'-diphenylmethane diisocyanate.   A polyurethane system obtained by applying the two-component reactive polyurethane-based electrical insulating paint according to any one of claims 1 to 4 directly on a conductor or through another insulating layer, and baking to form an insulating layer. Insulated wire.   The polyurethane-based insulated wire according to claim 5, wherein the insulating layer is an insulating layer that does not contain phenols as a residual solvent.