JP2012144679A - Reactive polyurethane-based electrical insulating coating material and insulated electric wire with insulating layer of the electrical insulating coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the frequency of application and baking of an electrical insulating coating material to the minimum, while suppressing deterioration of the electric wire characteristics of an insulated electric wire, degradation of the appearance, or the like, and to improve productivity of an insulated electric wire.SOLUTION: This reactive polyurethane-based electrical insulating coating material contains (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin, and does not contain a phenolic solvent.

Description

  The present invention relates to a reactive polyurethane-based electrically insulating paint and an insulated coated electric wire (insulated electric wire) having an insulating layer of the electrically insulating paint.

  Insulated wires (enameled wires) are coated with an electrically insulating coating on a conductor such as copper wire, copper clad wire, or aluminum wire directly or through another insulating layer, and baked (cured) to form an electrically insulating film (insulating layer). It is obtained by forming.

  In particular, polyurethane-based insulated wires are easily used for electrical and electronic equipment because they are easy to handle the end of insulated wires such as soldering, and have high-speed workability and high productivity compared to other insulated wires. Widely used.

  Polyurethane-based electrical insulation coatings used to form polyurethane-based insulated wires include blocked organic polysalts that are stabilized by blocking (masking) the isocyanate groups of organic polyisocyanates with phenolic solvents such as phenol, cresol, and xylenolic acid. A one-component solution in which an isocyanate compound and an active hydrogen-containing compound such as a polyol coexist is used.

  As the blocking agent (masking agent) used for the block organic polyisocyanate compound, phenol solvents such as phenol, cresol, xylenolic acid and the like are mainly used because of cost merit and high storage stability of the paint.

  Since the block organic polyisocyanate compound used for the one-component polyurethane-based electrical insulating paint has a high viscosity and is inferior in workability, it is necessary to adjust the paint viscosity with an organic solvent.

  The organic solvent used for this purpose is mainly composed of phenolic solvents such as phenol, cresol and xylenolic acid, which are highly soluble in blocked organic polyisocyanate compounds and active hydrogen-containing compounds. In order to increase the solvent, a solvent obtained by mixing xylol or solvent naphtha is used.

  However, phenolic solvents are deleterious and highly toxic to the human body. In addition, even when heated to a high temperature during the baking of electrical insulation paint, the phenolic solvent does not completely dissociate from the isocyanate group of the blocked organic polyisocyanate compound, and a considerable amount remains in the resulting electrical insulation film There is.

  The phenolic solvent remaining in the electrical insulation coating gradually diffuses into the atmosphere during use of electrical products and electronic equipment. Thereby, in addition to polluting the use environment such as the room, various problems such as a health hazard for the user are caused.

  In addition, the blocking agent of the blocked organic polyisocyanate compound and the organic solvent in the electrical insulating paint contribute to the coating stability of the electrical insulating paint and the coating workability during baking, but are vaporized in the baking furnace during baking and burned. To decompose carbon dioxide (greenhouse gas).

  Therefore, reduction of the amount of block agents and organic solvents used in the one-component polyurethane electrical insulating paint is also a major issue.

  Under such a technical background, reactive polyurethane-based electrical insulation paints have been replaced with conventional one-component polyurethane-type electrical insulation paints in order to reduce organic solvents and blocking agents in polyurethane-type electrical insulation paints. (For example, patent document 1 and patent document 2).

  In the reactive polyurethane-based electrical insulating paint, an isocyanate group-containing compound that does not require a blocking agent and an active hydrogen group-containing compound such as a polyol are individually separated, mixed, and then applied during coating and baking.・ An insulated wire can be obtained by baking.

  In addition, since no phenolic solvent is used in the paint, no phenolic solvent remains in the resulting electrical insulating film, and the residual solvent in the electrical insulating film can be greatly reduced.

JP 2006-45484 A JP 2006-89556 A

  As described above, in the production of an insulated wire (enameled wire), an electrical insulating paint is applied onto a conductor using a coating means such as a coater roll, and then the electrical insulating paint is baked in a baking furnace. Is done.

  Application and baking of electrical insulation paint on conductors are performed in multiple times to avoid problems such as deterioration of the electric wire characteristics of insulated wires caused by insufficient baking, defects in the appearance of crooked shapes and increase in residual solvent. .

  However, there is a problem that the production efficiency of insulated wires decreases as the number of times of application and baking increases.

  Therefore, the present invention has an object to improve the productivity of insulated wires by reducing the number of times of applying and baking the electrical insulating paint as much as possible while suppressing the deterioration of the wire characteristics of the insulated wires and the deterioration of the appearance of the crooked shape. It is what.

The above problem is solved by the following configuration.
(1) A reactive polyurethane-based electrically insulating paint comprising (a) an isocyanate group-containing polyurethane, (b) a polyol compound, (c) a polyamide resin, and no phenol solvent.
(2) (a) The isocyanate group-containing polyurethane is an isocyanate group-containing polyurethane obtained by reacting an aromatic polyisocyanate and a hydroxyl group-containing compound with an isocyanate group-excess condition with respect to a hydroxyl group. The reactive polyurethane-based electrically insulating paint as described.
(3) The reactive polyurethane electrical insulating paint according to (1) or (2), wherein the polyol compound is a polyester polyol.
(4) An electrically insulating layer is formed by applying and baking the reactive polyurethane-based electrically insulating paint according to any one of (1) to (3) on a conductor directly or through another insulating layer. A polyurethane-based insulated wire.
(5) preparing a reactive polyurethane-based electrical insulating paint containing (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin and not containing a phenol solvent, A polyurethane-based electrically insulating coating is formed by applying a reactive polyurethane-based electrically insulating coating onto a conductor or a conductor previously coated with an insulating layer, and baking it. Insulated wire manufacturing method.
(6) (a) The isocyanate group-containing polyurethane is an isocyanate group-containing polyurethane obtained by reacting an aromatic polyisocyanate and a hydroxyl group-containing compound with a hydroxyl group-excess condition with respect to a hydroxyl group. The manufacturing method as described.
(7) The production method according to (5) or (6), wherein the polyol compound is a polyester polyol.

  In the present invention, the term “reactive type” means that at least (a) an isocyanate group-containing polyurethane and (b) a polyol compound can react with each other during baking (curing) to form a cured film. Means that.

Moreover, in this specification, the number average molecular weight of the component except (c) polyamide resin is a value obtained by measuring GPC (gel permeation chromatography) under the following conditions and converting polystyrene as a standard substance.
<Measurement method of average molecular weight>
Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Detector: RI (differential refractive index)
Developing solvent: THF (tetrahydrofuran)
Flow rate: 0.3 ml / min
Temperature: 40 ° C

  Since the reactive polyurethane-based electrically insulating paint of the present invention does not contain a phenolic solvent which is a deleterious substance, it may cause pollution of the usage environment due to the gradual release of the phenolic solvent in the insulated wire. Absent.

  Furthermore, the reactive polyurethane electrical insulating paint of the present invention can improve the productivity of the insulated wire by reducing the number of times of application and baking while suppressing the appearance defect of the obtained insulated wire and the deterioration of the wire characteristics.

  Hereinafter, the present invention will be described in detail according to embodiments.

[Polyurethane-based electrical insulating paint]
The reactive polyurethane electrical insulating paint of the present invention contains (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin, and does not contain a phenol solvent. And Hereinafter, each of these components will be described.

(A) Isocyanate group-containing polyurethane (a) Isocyanate group-containing polyurethane in the present invention is not particularly limited, and generally known polyisocyanate and hydroxyl group-containing compound are mixed with the hydroxyl group of the hydroxyl group-containing compound. It is possible to use an isocyanate group-containing polyurethane obtained by reacting under an excess of groups.

  As the polyisocyanate, aromatic polyisocyanates are suitable. Aromatic polyisocyanates include 4,4′-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, or mixtures thereof, such as diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6 -Toluene diisocyanate or mixtures thereof such as toluene diisocyanate, phenylene diisocyanate, diphenyl diisocyanate, 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-naphthal Data diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethoxy-4,4'-diisocyanate. In addition, these can be used individually or in mixture of 2 or more types.

  Further, as aromatic polyisocyanates, so-called modified isocyanates such as adduct-modified, burette-modified, isocyanurate-modified, uretonimine-modified, uretdione-modified, carbodiimide-modified, etc. of the above-mentioned aromatic polyisocyanate, polymethylene polyphenyl poly It is also possible to use polyisocyanates called so-called polymeric bodies such as isocyanate, crude toluene polyisocyanate and the like. In addition, these can be used individually or in mixture of 2 or more types.

  Among these aromatic polyisocyanates, diphenylmethane diisocyanate, toluene diisocyanate and adducts, burettes, and isocyanates of these diisocyanates are easy to obtain and have good solderability and heat resistance of the resulting polyurethane-based insulated wires. Modified isocyanates such as a nurate modified product, a uretonimine modified product, a uretdione modified product, and a carbodiimide modified product are preferable, and diphenylmethane diisocyanate and modified isocyanates of diphenylmethane diisocyanate are particularly preferable.

  As the hydroxyl group-containing compound, from the viewpoint of obtaining a polyurethane-based electrical insulating paint having good storage stability and coating / baking workability, it means a molecular weight (in the case of a compound having a molecular weight distribution, it means a number average molecular weight. The same applies in the paragraph.) Polyols having a molecular weight of 1,000 or less are preferred, and polyols having a molecular weight of 500 or less are more preferred. Specific examples of such polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 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, Examples include 1,4-cyclohexanedimethanol, ethylene oxide or propylene oxide adduct of bisphenol A, trimethylolpropane, glycerin, pentaerythritol and the like. Moreover, it is also possible to use the polyester polyol, polycarbonate polyol, hydrocarbon polyol etc. which are mentioned as (b) polyol compound mentioned later.

  Among these, ethylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol are easy to obtain and have a good balance of solderability and heat resistance of the resulting polyurethane-based insulated wire. 1,6-hexanediol, trimethylolpropane and glycerin, and ethylene oxide or propylene oxide adducts of bisphenol A are preferred.

  Use of polyols such as polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene glycol, polybutadiene polyol, polyisobutylene polyol having a number average molecular weight of 1,000 to 4,000 for modification of isocyanate group-containing polyurethane You can also. These polyols can be used alone or in admixture of two or more.

  The equivalent ratio of isocyanate group to hydroxyl group in the reaction of the polyisocyanate and the hydroxyl group-containing compound of the isocyanate group-containing polyurethane is preferably isocyanate group / hydroxyl group = 1.1 / 1 to 10/1, more preferably 1.8 / 1 to 5 / 1 is preferred.

  Further, the isocyanate group (NCO group) content in the isocyanate group-containing polyurethane is 1 to 30% by mass in terms of solid content of 100% by mass in order to obtain a polyurethane-based electrical insulating paint having good coating and baking workability. Is preferable, and it is more preferable that it is 5-25 mass%.

  The number average molecular weight of the isocyanate group-containing polyurethane is preferably in the range of 300 to 3,000, particularly 500 to 2,000. When the number average molecular weight is less than 300, smoke due to sublimation / pyrolysis of the isocyanate group-containing polyurethane is likely to occur from the exit of the baking furnace when applying and baking the reactive polyurethane electrical insulating paint of the present invention, If it exceeds 000, the resin concentration of the isocyanate group-containing polyurethane increases, and there is a possibility that good coating and baking workability cannot be ensured.

(B) Polyol compound Specifically, the (b) polyol compound in the present invention is a high molecular polyol having a number average molecular weight of 500 to 3,000, particularly 500 to 2,000, and a low molecular polyol having a number average molecular weight of less than 500. Polymer polyols are preferred in terms of good electric wire characteristics such as film formability, heat resistance, and flexibility of the resulting insulated wire.

  Specific examples of the polymer polyols include polyester polyols, imide-modified polyester polyols, polyurethane polyols, polyether polyols, polycarbonate polyols, hydrocarbon polyols, poly (meth) acrylic polyols, animal and plant polyols, and copolyols thereof. Is mentioned. These can be used individually or in mixture of 2 or more types.

  Of these, polyester polyols, imide-modified polyester polyols, and polyurethane polyols are preferable, and polyester polyols are particularly preferable in terms of a good balance between solderability and heat resistance of the obtained insulated wires.

  The polyester polyol is a polyester polyol obtained by reacting an acid component and an alcohol component with an alcohol component in excess of the acid component and having a hydroxyl group at the terminal.

  Specific examples of the acid component include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, phthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, and naphthalene dicarboxylic acid. Examples thereof include polycarboxylic acids such as acids, ester derivatives such as methyl esters and ethyl esters of these polycarboxylic acids, and acid anhydrides.

  Examples of the alcohol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 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 And trimethylolpropane, glycerin, pentaerythritol, and ethylene oxide or propylene oxide adducts of bisphenol A, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polybutadiene Down polyols, such as polyisobutylene polyols are preferred.

  Such an acid component and an alcohol component can be used alone or in admixture of two or more. The equivalent ratio of hydroxyl group to acid group in the reaction of the acid group (equivalent carboxyl group) of the acid component with the alcohol component is preferably hydroxyl group / acid group = 1.1 / 1 to 10/1, and more preferably 1 .8 / 1 to 5/1 are preferred.

  The imide-modified polyester polyol is obtained by reacting an alcohol component with an imide group-containing polycarboxylic acid and / or an imide group-containing polycarboxylic acid derivative (an ester compound of an imide group-containing polycarboxylic acid, an acid anhydride, etc.) Is an imide-modified polyester polyol having a hydroxyl group. Although there is no restriction | limiting in particular in the alcohol component which can be used, The alcohol component which can be used by reaction of the said polyester polyol can be illustrated suitably from the point of the heat resistance of the insulated wire obtained and production efficiency.

  The imide group-containing carboxylic acid and / or imide group-containing polycarboxylic acid derivative can be obtained from a diamine component and an acid component, for example, obtained by reacting 2 mol of trimellitic anhydride with 1 mol of diamine. Etc. Specific examples of the diamine include 4,4′-diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, 1,4-diaminonaphthalene, 4,4′-diaminodiphenyl ether, hexamethylenediamine, and diaminodiphenylsulfone. These may be used alone or in combination of two or more. In order to obtain an imide group-containing polycarboxylic acid and / or an imide group-containing polycarboxylic acid derivative, a diisocyanate component may be used instead of the diamine component.

  Synthesis of imide group-containing polycarboxylic acid and / or imide group-containing polycarboxylic acid derivative by reaction of these diamine component and acid component, and reaction of alcohol component with imide group-containing polycarboxylic acid and / or imide group-containing polycarboxylic acid derivative May be performed in a lump, or each reaction may be divided.

  The synthesis of the polyester polyol and the imide-modified polyester polyol can be suitably performed by reacting the alcohol component and the acid component or the diamine component at a temperature of 100 to 250 ° C. while removing by-products from the system. it can. Moreover, reaction catalysts, such as zinc acetate, manganese acetate, TBT, TPT, can be used individually or in mixture of 2 or more types as needed.

  The polyurethane polyol has a hydroxyl group-terminated polyurethane polyol obtained by reacting an isocyanate group of an aromatic polyisocyanate with a hydroxyl group of a hydroxyl group-containing compound under a hydroxyl-excess condition.

  Preferable examples of the aromatic polyisocyanate and the hydroxyl group-containing compound that can be used when synthesizing a polyurethane polyol include the aromatic polyisocyanate and the hydroxyl group-containing compound that can be used for the above-mentioned (a) isocyanate group-containing compound. be able to.

  Moreover, as a method of synthesizing the polyurethane polyol, the reaction can be carried out under the same temperature conditions as in the above-described method (a) of synthesizing the isocyanate group-containing polyurethane. The equivalent ratio of the hydroxyl group of the hydroxyl group-containing compound to the isocyanate group of the aromatic polyisocyanate when synthesizing the polyurethane polyol is preferably hydroxyl group / isocyanate group = 1.1 / 1 to 10/1, more preferably 1.5 / 1-5 / 1 is preferable. The hydroxyl group (OH group) content in the polyurethane polyol 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 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-based polyols include castor oil-based polyols and silk fibroin.

  The blending ratio of (a) isocyanate group-containing polyurethane and (b) polyol compound is the equivalent ratio of (a) isocyanate group of the isocyanate group-containing polyurethane and (b) hydroxyl group of the polyol compound, isocyanate group / hydroxyl group = 0. .3 / 1 to 2.0 / 1, more preferably 0.5 / 1 to 1.5 / 1, and particularly preferably 0.7 / 1 to 1.3 / 1. If the isocyanate group / hydroxyl group is less than 0.3 / 1, the reaction in the baking furnace may become insufficient and the heat resistance may be reduced. If the isocyanate group / hydroxyl group exceeds 2.0 / 1, the isocyanate is discharged from the baking furnace outlet. Smoke resulting from sublimation and thermal decomposition of the group-containing polyurethane is likely to occur.

(C) Polyamide resin (c) Polyamide resin in the present invention is not particularly limited, and specifically, ring-opening polymerization of cyclic lactams such as ε-caprolactam and lauryl lactam, or ω-amino Examples thereof include polyamide resins obtained by condensation of carboxylic acid, copolymerization of diamine and dibasic acid, and the like. There are no limitations on the types of lactams, diamines, dibasic acids, etc., which may be any of aromatic polyamides, semi-aromatic polyamides, and aliphatic polyamides.

  Examples of the aromatic polyamide include poly-p-phenylene terephthalamide (DuPont: Kevlar) and poly-m-phenylene isophthalamide (DuPont: Nomex) obtained from p-phenylenediamine and terephthalic acid chloride. Examples of the aromatic polyamide include polyhexamethylene terephthalamide obtained from hexamethylene diamine and terephthalic acid, and polynonanemethylene terephthalamide obtained from nonanemethylene diamine and terephthalic acid. Examples of the aliphatic polyamide include ε-caprolactam. Nylon 6 obtained, nylon 11 obtained from undecane lactam, nylon 12 obtained from lauryl lactam, nylon 6,6 obtained from hexamethylenediamine and adipic acid, hexamethylene di Nylon 6,10 obtained from Min and sebacic acid, lauryllactam and ε- caprolactam, nylon 6,12 or nylon 10, 12 obtained from decane lactam and the like.

（式中、ａは４〜１５の整数であり、ｂは２〜１５の整数であり、ｃは４〜１５の整数であり、ｍは０〜６５（好ましくは１０〜６５）の整数であり、ｎは０〜４０（好ましくは１０〜４０）の整数であり、ｐは１５〜３５の整数であり、ｑは５〜３５の整数であり、但しｍ＋ｎ＋ｐ＋ｑ＝１００である）で表される構造単位を有する共重合脂肪族系ポリアミド樹脂が好適である。 Of these, aliphatic polyamide is preferable because the obtained insulated wire has good flexibility, heat shock, and solderability. Among aliphatic polyamides, copolymer aliphatic polyamides are preferred because the resin has relatively low crystallinity and good solubility in organic solvents.
In particular, the following general formula (I):

(In the formula, a is an integer of 4 to 15, b is an integer of 2 to 15, c is an integer of 4 to 15, and m is an integer of 0 to 65 (preferably 10 to 65). , N is an integer of 0-40 (preferably 10-40), p is an integer of 15-35, q is an integer of 5-35, provided that m + n + p + q = 100. Copolymer aliphatic polyamide resins having units are preferred.

  In particular, quaternary copolymer obtained by polymerizing ε-caprolactam (a = 5), 4,4′-diamino-dicyclohexylmethane, adipic acid (b = 4) and 1,6-hexamethylenediamine (c = 6) Is preferred. The quaternary copolymer is not particularly limited in its structure (random or block) as long as the four structural units in the general formula (I) are copolymerized at the above ratio.

  Furthermore, the polyamide resin preferably has a number average molecular weight of 10,000 to 60,000, particularly preferably 20,000 to 40,000. When the number average molecular weight of the polyamide resin is less than 10,000, the effect of improving the appearance and heat shock of the obtained polyurethane insulated wire is small. Moreover, when the number average molecular weight of a polyamide resin exceeds 60,000, the viscosity of a polyamide resin solution is too high, and application | coating and baking workability deteriorates.

  The “number average molecular weight” for the polyamide resin means a value measured as follows.

<Conditions for measuring number average molecular weight of polyamide resin>
Using a GPC apparatus (trade name: HLC-8220GPC, manufactured by Tosoh Corporation), at a temperature of 40 ° C., a 0.25 wt% hexafluoroisopropanol solution of the sample is used as the sample solution, and the injection amount of the sample solution is 100 mL, and the molecular weight Find the distribution curve. The molecular weight of the peak of the obtained molecular weight distribution curve is determined as the peak top molecular weight. Further, the number average molecular weight is obtained from the obtained molecular weight distribution curve. The molecular weight calibration curve is prepared using standard polystyrene.

  Examples of the polyamide resin represented by the general formula (I) include, for example, Tadahiro Miwa, “Chemistry of Basic Synthetic Resin (New Edition)”, Gihodo Publishing Co., Ltd., November 1975, p. It can be obtained by a general polyamide synthesis method described in 305-326 and the like.

  The production method of the polyamide resin is not particularly limited, and a normal polyamide polycondensation method, a melt polymerization method, a solution polymerization method, an interfacial polymerization method and the like can be appropriately applied. In the polymerization, a monobasic acid such as acetic acid or benzoic acid, or a monoacid base such as hexylamine or aniline may be used as a molecular regulator. The copolymerization ratio is not particularly limited, but the diamine component is preferably 5 to 40 mol%, particularly preferably 5 to 30 mol%.

  A commercially available polyamide resin can also be used as the polyamide resin represented by the general formula (I). As a commercially available polyamide resin, the brand name made from BASF: Ultramid 1C etc. are mentioned, for example.

  (C) As content of a polyamide resin, in order to show sufficient effect, it is 0.1-10 mass with respect to 100 mass parts of total resin content of (a) isocyanate group containing polyurethane and (b) polyol compound. Part, particularly 0.5 to 5 parts by mass. When content of a polyamide resin exceeds 10 mass parts, the solderability and heat resistance of the polyurethane type insulated wire obtained will fall.

Other Components Conventionally known additives such as an organic solvent, a curing accelerating catalyst, a curing inhibiting catalyst, a lubricity imparting agent, and a coloring agent can be added to the polyurethane-based electrical insulating paint of the present invention as necessary. .

  As an organic solvent, the well-known organic solvent which does not react with an isocyanate group can be mentioned. Specifically, an organic solvent having no active hydrogen in the compound is preferable. When there is active hydrogen, it reacts with the (a) isocyanate group-containing polyurethane in the present invention, and there is an adverse effect such as thickening or (a) the isocyanate group-containing polyurethane solidifies at room temperature.

  Specific examples of the organic solvent having no active hydrogen include n-hexane, 2-methylpentane, n-heptane, n-octane, 2,2,3-trimethylpentane, and 2,2,4-trimethyl. Aliphatic hydrocarbon solvents such as pentane, n-nonane, 2,2,5-trimethylhexane, n-decane and n-dodecane: Alicyclic hydrocarbon solvents such as cyclohexane: xylene, ethylbenzene, trimethylbenzene, isopropyl Aromatic hydrocarbon solvents such as benzene, butylbenzene, diethylbenzene, pentylbenzene, dipentylbenzene, cyclohexylbenzene, naphthalene, tetralin, biphenyl: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, Butyl propionate, methyl butyrate, dairy Ester solvents such as ethyl, butyl butyrate, butyl stearate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, γ-butyrolactone, diethyl malonate; N, N-dimethylacetamide, N-methylpyrrolidone, etc. Amide solvents of: ketone solvents such as methyl isobutyl ketone, cyclohexanone, methyl cyclohexanone, isophorone and acetophenone: acetate solvents such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, methoxypropyl acetate and methoxybutyl acetate: Etc. Further, dimethyl sulfoxide, petroleum naphtha, coal tar naphtha, solvent naphtha, and the like, and mixtures thereof are also included. These organic solvents not having active hydrogen can be used alone or in admixture of two or more. The boiling point of the organic solvent is 60 ° C. to 300 ° C., more preferably 80 ° C. to 250 ° C., particularly 100 ° C. to 250 ° C. from the viewpoint of improving the coating / baking workability and reducing the residual solvent contained in the insulated wire. The range of is preferable. Moreover, as content of an organic solvent, the total amount of (a) isocyanate group containing polyurethane and (b) polyol compound is 60 mass from a viewpoint of reducing the residual solvent contained in an insulated wire, and reducing the frequency | count of application | coating and baking. 40 parts by mass or less is preferable with respect to parts.

  Examples of the curing accelerating catalyst include organometallic compounds and amines. Specifically, divalent organic tin compounds such as tin octylate, tin octenoate and tin naphthenate, dibutyltin dioctate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dimaleate, dibutyltin distearate, dioctyltin dilaurate, Divalent tin diversate, dibutyltin oxide, dibutyltin bis (triethoxysilicate), tetravalent organotin compounds such as reaction product of dibutyltin oxide and phthalate, dibutyltin bis (acetylacetonate), tin-based chelate compound EXCESTARC-501 manufactured by Asahi Glass Co., Ltd., zirconium tetrakis (acetylacetonate), titanium tetrakis (acetylacetonate), aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate) Chelating compounds of various metals such as acetylacetone cobalt, acetylacetone iron, acetylacetone copper, acetylacetone magnesium, acetylacetone bismuth, acetylacetone nickel, acetylacetone zinc, acetylacetone manganese, lead acid salts such as lead octylate, tetra-n-butyl titanate, tetrapropyl Titanates such as titanate, organic bismuth compounds such as bismuth octylate and bismuth versatate, triethylamine, tributylamine, triethylenediamine, hexamethylenetetramine, 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) ), Tertiary amines such as 1,4-diazabicyclo [2,2,2] octane (DABCO), N-methylmorpholine, N-ethylmorpholine, or It can be mentioned salts such as these amines and carboxylic acids. These curing accelerating catalysts increase the viscosity after mixing (a) isocyanate group-containing polyurethane and (b) polyol compound, and may deteriorate the workability of applying and baking electrical insulating paints. Is preferably selected in consideration of the increase in viscosity after mixing.

  Curing inhibition catalysts include phosphoric acid esters, phosphites, organic acids such as formic acid, acetic acid and propionic acid, active methylene compounds such as dimethyl malonate, diethyl malonate, ethyl acetoacetate and acetylacetone, hydrochloric acid and sulfuric acid And inorganic acids. These can be used individually or in mixture of 2 or more types. Among these, phosphate esters and phosphites are preferable in that the reaction suppressing effect between (a) the isocyanate group-containing polyurethane and (b) the polyol compound is high.

  Specific examples of phosphate esters include methyl acid phosphate, dimethyl acid phosphate, ethyl acid phosphate, diethyl acid phosphate, propyl acid phosphate, isopropyl acid phosphate, dipropyl acid phosphate, monobutyl acid phosphate, dibutyl acid phosphate, 2-ethylhexyl acid phosphate, bis (2-ethylhexyl) phosphate, isodecyl acid phosphate, monoisodecyl phosphate, butyl pyrophosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, ethylene glycol acid phosphate, (2 -Hydroxyethyl) methacrylate acid phos Eto, and the like. Among these, the reaction suppressing effect between (a) the isocyanate group-containing polyurethane and (b) polyol compound at room temperature is high and the viscosity increase after mixing them is suppressed, while the reaction suppressing effect at high temperature baking is small. Diethyl acid phosphate, dibutyl acid phosphate, and 2-ethylhexyl acid phosphate that are difficult to inhibit the formation of an insulating film are more preferable.

  Specific examples of phosphites include triphenyl phosphite, tris (nonylphenyl) phosphite, triethyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, tri Octyl phosphite, trinonyl phosphite, tridecyl phosphite, trilauryl phosphite, tris (tridecyl) phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono (tridecyl) phosphite, Trioleyl phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4 4'-isopropylidene diphenyl diphosphite, tridodecyl trithiophosphite, trioctadecyl phosphite, tris (2,4-di -t- butyl-phenyl) phosphite.

  Specific examples of the lubricity-imparting agent include natural waxes such as candelilla wax, carnauba wax, rice wax, wax, beeswax, and lanolin.

  Specific examples of the colorant include copper phthalocyanine dyes, chromium complex dyes, and azo dyes.

  The reactive polyurethane electrical insulating paint of the present invention contains the components (a) to (c) described above, but does not contain a phenol solvent.

  In addition, as a main phenol-type solvent, it is a compound which may have a bad influence on a human body, such as phenol, cresol, and xylenoleic acid.

  In the present invention, the resin concentration (nonvolatile content) of the reactive polyurethane-based electrically insulating paint by the organic solvent is adjusted such that (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin are the same resin. The concentration may be adjusted in advance, or one may be adjusted at a high concentration and the other may be adjusted at a low concentration so that a desired resin concentration is obtained when they are mixed. Alternatively, any or all of these may be adjusted to a high concentration, and an organic solvent may be added during mixing to achieve a desired resin concentration. Which method should be adopted may be appropriately selected in consideration of ease of adjustment and ease of storage.

  The amount of the organic solvent used in the present invention is (a) an isocyanate group-containing polyurethane in terms of preventing environmental pollution, reducing the residual solvent in the electrical insulating layer of the resulting insulated wire, and reducing the number of times of coating and baking. It is preferable to use it so that the resin concentration when (b) the polyol compound and (c) the polyamide resin are mixed is 60% by mass or more in the polyurethane-based electrical insulating paint.

  The mixing method of (a) isocyanate group-containing polyurethane, (b) polyol compound, and (c) polyamide resin in the present invention is not particularly limited, and a conventionally known mixing method can be used. Specific examples include a mixing mixer such as a stirring motor with stirring blades, a static mixer, and the like.

[Polyurethane insulated wire and method for producing the same]
The polyurethane-based insulated wire of the present invention forms the (electric) insulating layer by applying and baking (curing) the reactive polyurethane-based electric insulating paint directly on the conductor or through another insulating layer. Become.

  Specific examples of the conductor include copper, nickel-plated copper, copper-clad aluminum, aluminum, gold, and gold-plated, which are generally used as conductors for electric wires. As other insulating layers, specifically, a polyvinyl formal insulating layer, a polyurethane insulating layer, a polyester insulating layer, a polyester imide insulating layer, a polyhydantoin insulating layer, a polyamide imide insulating layer, a polyimide insulating layer For example, an insulating layer may be used.

In addition, what is necessary is just to select suitably the thickness of the film | membrane by the reaction type polyurethane-type electrically insulating coating material of this invention, or the total thickness with another film | membrane according to the thickness and required performance of conductors, such as a copper wire to be used. When the desired film thickness is not formed by one application and baking, the application and baking may be repeated as many times as necessary. As a method of mixing and applying the paint, (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin are mixed by a known mixing method, or mixed directly on the conductor or other insulation. A predetermined amount may be applied through a layer by a felt drawing method, a die drawing method, or the like.
Although it does not restrict | limit especially as temperature at the time of baking, From the viewpoint of making hardening reaction sufficient and reducing a residual solvent, the range of 180 to 600 degreeC, especially 200 to 550 degreeC is preferable.

  By using the reactive polyurethane electrical insulating paint of the present invention, a cured film having a coating thickness of 5 to 15 μm, further 6 to 14 μm, particularly 7 to 12 μm per coating / baking operation is poor in appearance. And it can form, suppressing the fall of an electric wire characteristic.

  In addition, another insulating layer and / or a fusion layer can be provided on the polyurethane-based insulated wire formed by applying and baking the reactive polyurethane-based electrically insulating paint of the present invention. Specific examples of other insulating layers include polyvinyl formal, polyurethane, polyester, polyester imide, polyhydantoin, polyamide imide, polyimide, and the like. As the fusion layer, phenoxy resin, Examples include butyral resin and polyamide resin.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Measurement conditions (1) Non-volatile content (solid content)
JIS C2531: 2006 “varnish for enamel wire” 8.3 According to non-volatile content.
However, (a) the isocyanate group-containing polyurethane had a drying temperature of 150 ° C., and (b) the polyol compound and (c) the amide group-containing compound had a drying temperature of 170 ° C.
(2) Isocyanate group (NCO group) content JIS K1603-1: 2007 "Plastics-Polyurethane raw material aromatic isocyanate test method-Part 1: Determination of isocyanate group content" According to method B (toluene / TCB / dibutylamine / hydrochloric acid (methanol solvent) method).
(3) Acid value and hydroxyl value JIS K1557-12007 "Plastic-Polyurethane raw material polyol test method-Part 1: How to obtain hydroxyl group" According to method A (acetylation method).
(4) Viscosity JIS C2531: 2006 “varnish for enameled wire” 8.2 According to viscosity.

Synthesis Example 1: Production of isocyanate group-containing polyurethane 1
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube and a heating device, 656 g of coronate MX (manufactured by Nippon Polyurethane Industry Co., Ltd.) which is a modified carbodiimide of 4,4′-diphenylmethane diisocyanate, trimethylolpropane (Guangei Chemical) 25 g of Kogyo Co., Ltd. and 69 g of neopentyl glycol (Mitsubishi Gas Chemical Co., Ltd.) were respectively charged, heated under a nitrogen stream, and reacted at 80 ° C. for 2 hours to synthesize an isocyanate group-containing urethane prepolymer. Next, 125 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries) and 125 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added to the reaction vessel to dissolve and dilute the isocyanate group-containing urethane prepolymer. Thus, an isocyanate group-containing urethane prepolymer solution (a1) having an NCO group content of 11% by mass, a viscosity of 4,500 mPa · s / 30 ° C., and a nonvolatile content of 75% by mass was obtained.

Synthesis Example 2: Production 2 of isocyanate group-containing polyurethane
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube and a heating device, 298 g of 4,4′-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.), coronate which is a modified carbodiimide of 4,4′-diphenylmethane diisocyanate 346 g of MX (manufactured by Nippon Polyurethane Industry Co., Ltd.), 25 g of trimethylolpropane (manufactured by Guangei Chemical Industry Co., Ltd.), and 81 g of neopentyl glycol (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were respectively charged and heated in a nitrogen stream at 2 ° C. By reacting for a time, an isocyanate group-containing urethane prepolymer was synthesized. Next, 125 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries) and 125 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added to the reaction vessel to dissolve and dilute the isocyanate group-containing urethane prepolymer. Thus, an isocyanate group-containing urethane prepolymer solution (a2) having an NCO group content of 11% by mass, a viscosity of 3,500 mPa · s / 30 ° C., and a nonvolatile content of 75% by mass was obtained.

Synthesis Example 3 Production of Polyester Polyol In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and condenser, and heating device, 364 g of phthalic anhydride (Mitsubishi Gas Chemical Co., Ltd.) and trimethylolpropane (Guangei Chemical Industry Co., Ltd.) 329g and 1,6-hexanediol (Ube Industries) 145g, heated under a nitrogen stream without using a catalyst and confirmed the dissolution of the raw material at 130 ° C. While removing to the outside, the temperature was raised to 200 ° C. over 5 hours, and the reaction was continued at 200 ° C. as it was. After confirming that the acid value of the contents was 5 KOH mg / g or less, the reaction was terminated by reducing the pressure. Next, 125 g of methyl 1,3-butylene glycol acetate (manufactured by Daicel Chemical Industries, Ltd.) and 125 g of methyl isobutyl ketone (manufactured by Kyowa Hakko Kogyo Co., Ltd.) are added and dissolved in the reaction vessel to obtain a hydroxyl value of 366 (mgKOH / g), A polyester polyol solution having a viscosity of 3,300 (mPa · s / 30 ° C.) and a nonvolatile content of 75% by mass was obtained.

Example 1
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and heating device, 50 g of Ultramid 1C (manufactured by BASF), a copolymerized aliphatic polyamide, and 450 g of dimethyl sulfoxide (manufactured by Sankyo Chemical Co., Ltd.) are charged. Then, the mixture was heated under a nitrogen stream, and the copolymerized polyamide was dissolved at 100 ° C. for 1 hour to obtain a 10% by mass copolymerized polyamide solution.

  Next, 500 g of the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 and 112 g of the copolymerized polyamide solution were respectively charged in a stainless steel 2 L beaker with a stirrer. After stirring until well mixed, the mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.

The injected mixed solution was applied and baked on a 0.40 mmφ copper wire in three passes under the following conditions to produce a polyurethane insulated wire having a film thickness of 20 μm.
Application and baking conditions:
(1) Number of applications (die arrangement)
3 passes: 0.43 mmφ × 1, 0.45 mmφ × 1, 0.46 mmφ × 1
(2) Baking furnace: Horizontal electric furnace (furnace length 2.7m)
(3) Furnace temperature: 330 ° C (inlet)-380 ° C (outlet)
(4) Line speed: 19 m / min

Example 2
A polyurethane-based insulated wire having a film thickness of 20 μm was manufactured in the same manner as in Example 1 except that the number of times of application was 2 passes (dies array: 0.44 mmφ × 1, 0.48 mmφ × 1).

Example 3
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and heating device, 50 g of Ultramid 1C (manufactured by BASF), 450 g of dimethyl sulfoxide (manufactured by Sankyo Chemical Co., Ltd.), which is a copolyamide, is charged and a nitrogen stream Under heating, the copolymerized polyamide was dissolved for 1 hour at 100 ° C. to obtain a 10% by mass copolymerized polyamide solution.

  Next, 500 g of the isocyanate group-containing urethane prepolymer solution (a2) obtained in Synthesis Example 2 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 and 112 g of the copolymerized polyamide solution were respectively charged in a stainless steel 2 L beaker with a stirrer. After stirring until well mixed, the mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.

The injected mixed solution was applied and baked on a 0.40 mmφ copper wire in three passes under the following conditions to produce a polyurethane insulated wire having a film thickness of 20 μm.
Application and baking conditions:
(1) Number of applications (die arrangement)
3 passes: 0.43 mmφ × 1, 0.45 mmφ × 1, 0.46 mmφ × 1
(2) Baking furnace: Horizontal electric furnace (furnace length 2.7m)
(3) Furnace temperature: 330 ° C (inlet)-380 ° C (outlet)
(4) Line speed: 19 m / min

Example 4
In Example 3, a polyurethane insulated wire having a film thickness of 20 μm was manufactured in the same manner except that the number of times of application was 2 passes (die arrangement: 0.44 mmφ × 1, 0.48 mmφ × 1).

Comparative Example 1
In a stainless steel 2 L beaker, 500 g of the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 were charged and stirred with a stirrer until sufficiently mixed. The mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.

  A polyurethane system having a film thickness of 20 μm as in Example 1 except that the injected mixed solution was baked by 3 passes (dies array: 0.43 mmφ × 1, 0.45 mmφ × 1, 0.45 mmφ × 1). An insulated wire was manufactured.

Comparative Example 2
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and heating device, phenoxy resin YP-50 (manufactured by Nippon Steel Chemical Co., Ltd.) 50 g, cyclohexanone (manufactured by Sankyo Chemical Co., Ltd.) 315 g, xylene Each 135 g was charged and heated under a nitrogen stream, and the phenoxy resin was dissolved at 100 ° C. for 1 hour to obtain a 10% by mass phenoxy resin solution.

Next, 500 g of the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 and 112 g of the phenoxy resin solution were respectively charged in a stainless steel 2 L beaker and sufficiently stirred. Then, the mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.
The injected mixed solution was applied and baked under the same conditions as in Example 1 to produce a polyurethane insulated wire having a film thickness of 20 μm.

Comparative Example 3
In a reaction vessel equipped with a stirrer, thermometer, nitrogen seal tube and warming device, 50 g of butyral resin ESREC B (manufactured by Sekisui Chemical Co., Ltd.), 315 g of cyclohexanone, and 135 g of xylene were charged, respectively, and heated under a nitrogen stream. Then, the butyral resin was dissolved at 100 ° C. for 1 hour to obtain a 10 mass% butyral resin solution.

  Next, 500 g of the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 and 112 g of the butyral resin solution were respectively charged in a stainless steel 2 L beaker and sufficiently stirred. Then, the mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.

  The injected mixed solution was applied and baked under the same conditions as in Example 1 to produce a polyurethane insulated wire having a film thickness of 20 μm.

Comparative Example 4
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube and a heating device, Daisodap, which is a diallyl phthalate resin; 50 g of Type A (manufactured by Daiso), 315 g of cyclohexanone, and 135 g of xylene are charged under nitrogen flow. The diallyl phthalate resin was dissolved at 100 ° C. for 1 hour to obtain a 10% by mass diallyl phthalate resin solution.

  Next, 500 g of the isocyanate group-containing urethane prepolymer solution (a1) obtained in Synthesis Example 1 and 500 g of the polyester polyol solution obtained in Synthesis Example 3 and 112 g of diallyl phthalate resin solution were respectively charged in a stainless steel 2 L beaker with a stirrer. After stirring until well mixed, the mixed solution was poured into a varnish bath. In addition, the ratio of the isocyanate group of the isocyanate group-containing urethane prepolymer and the hydroxyl group of the polyester polyol in the mixed solution is 1.0.

  The injected mixed solution was applied and baked under the same conditions as in Example 1 to produce a polyurethane insulated wire having a film thickness of 20 μm.

Comparative Example 5
After adjusting 1000g of APU-2842S, a one-component polyurethane electrical insulating paint, it was injected into the varnish bath and applied 3 times (die arrangement: 0.45mmφ × 1, 0.47mmφ × 1, 0.49mmφ × 1) A polyurethane insulated wire having a film thickness of 20 μm was produced by coating and baking under the same conditions as in Example 1 except that.

Using polyurethane-based insulated wires produced in performance test examples 1 to 4 and comparative examples 1 to 5, each of wire appearance evaluation, softening resistance test, dielectric breakdown voltage test, solderability, flexibility, heat shock The electric wire characteristic test and the residual solvent in the insulating film were measured.
(1) Electric wire appearance evaluation JIS C2351: 2006 “varnish for enameled wire” 8.6 According to electric wire appearance.
The appearance of the electric wire after 1 hour of baking was evaluated by visual observation, the surface having a smooth and uniform gloss and color was evaluated as ◯, and the other one was evaluated as ×.
(2) Softening resistance test JIS C3003: 1999 “Enamelled wire test method” 11.2B method, b) According to the crossing method. The mass of the weight was tested with one type.
(3) Dielectric breakdown voltage test JIS C3003: 1999 “Enamelled wire test method” 10.2B method, b) According to two methods.
(4) Solderability According to JIS C3003: 1999 “Enamelled wire test method” 14.2B method.
(5) Flexibility After the test wire was stretched by 20% with a tensile tester, a flexibility test was conducted in accordance with JIS C3003: 1999 “Enamel wire test method” 7.2B method. A case where a crack in which a conductor was visible on the film did not occur was evaluated using a 10 × magnifier, and a case where a crack in which a conductor was visible on the film was evaluated was evaluated as x.
(6) Heat Shock After extending the test wire by 20% with a tensile tester, a wound electric wire was obtained in accordance with JIS C3003: 1999 “Enameled wire test method” 7.2B method. The wound wire was placed in an oven at 200 ° C. for 1 hour, and then the wound wire was taken out of the oven and left at room temperature for 30 minutes. Thereafter, a case where a crack in which the conductor was visible on the film was not generated was evaluated using a 10-fold magnifier, and a case where a crack in which the conductor was visible on the film was evaluated was evaluated as x.
(7) Measurement of residual solvent concentration in electrical insulating film 5 g of the obtained polyurethane electrical 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). The container was heated at 150 ° C. for 60 minutes.

  Residual solvent generated from the electrical insulating film by heating was gas chromatographic method using GC-14B manufactured by Shimadzu Corporation (measurement conditions were HR-1701 column manufactured by Shimadzu Corporation, carrier gas helium, flow rate 40 ml / min, detector FID, injection 180 And a start temperature of 45 ° C., a heating rate of 5 ° C./min, and a final temperature of 160 ° C.). From the obtained measurement results, the residual solvent concentration in the electrical insulating film was determined by the following formula.

Residual solvent amount (ppm) = measured by GC (μg) / film mass (g)
Film mass = wire mass (g) × (film adhesion rate / 100)
Coating rate (%) = 1.3π (D22−D12) / [8.89πD12 + 1.3π (D22−D12)] × 100
D1: Conductor diameter D2: Wire outer diameter

  From the results of Examples 1 to 4, if application and baking are performed using the reactive polyurethane electrical insulating paint of the present invention, the number of times of application with a die is reduced to 2 passes and 3 passes. It can be seen that the appearance is good. In addition, phenolic solvents do not remain in the insulation film of the insulated wire obtained, and the residual solvent amount of other organic solvents is extremely low compared to the one-component polyurethane-based electrical insulating paint (Comparative Example 5). I understand. Furthermore, the insulated wire of the present invention has good wire properties such as softening resistance, solderability, and flexibility even when the number of times of coating and baking is reduced, and is 200 ° C.-1 hour. The heat shock after heat treatment was also improved. It is considered that the heat shock can be improved by imparting flexibility to the obtained insulating film by the polyamide resin.

  As described above, the reactive polyurethane electrical insulating paint of the present invention makes it possible to increase the production efficiency of an insulated wire by reducing the number of times of application and baking while maintaining good appearance and electrical wire characteristics.

Claims (7)

(A) an isocyanate group-containing polyurethane;
(B) a polyol compound;
(C) A reactive polyurethane-based electrically insulating paint characterized by containing a polyamide resin and not containing a phenol-based solvent.   The reaction according to claim 1, wherein (a) the isocyanate group-containing polyurethane is an isocyanate group-containing polyurethane obtained by reacting an aromatic polyisocyanate and a hydroxyl group-containing compound with an isocyanate group-excess condition with respect to a hydroxyl group. Type polyurethane electrical insulating paint.   (B) The reactive polyurethane electrical insulating paint according to claim 1, wherein the polyol compound is a polyester polyol.   A polyurethane-based insulation comprising an electrically insulating layer formed by applying and baking the reactive polyurethane-based electrically insulating paint according to any one of claims 1 to 3 on a conductor directly or via another insulating layer. Electrical wire. Preparing a reactive polyurethane-based electrically insulating coating containing (a) an isocyanate group-containing polyurethane, (b) a polyol compound, and (c) a polyamide resin and not containing a phenolic solvent;
The polyurethane-based electrical insulation paint is applied onto a conductor or a conductor previously coated with an insulation layer and baked to form an electrical insulation layer made of the polyurethane-based electrical insulation paint. Electric wire manufacturing method.   6. The production according to claim 5, wherein (a) the isocyanate group-containing polyurethane is an isocyanate group-containing polyurethane obtained by reacting an aromatic polyisocyanate and a hydroxyl group-containing compound with a hydroxyl group under an excess of isocyanate groups. Method.   The production method according to claim 5 or 6, wherein the polyol compound is a polyester polyol.