JP2010108758A - Phenoxy resin insulating varnish and insulation wire using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating varnish capable of forming an insulating film which is superior in adhesion property with a conductor even after heat treatment and has softening resistance even under a high load condition, and to provide an insulation wire using the insulating varnish. <P>SOLUTION: A phenoxy resin insulating varnish contains 100 pts.mass of a phenoxy resin comprising 80-30 wt.% of bisphenol A-type phenoxy resin and 20-70 wt.% of bisphenol S-type phenoxy resin and 5-50 pts.mass of block isocyanate. It is desirable that a glass transition point of the bisphenol A-type phenoxy resin is 60-90°C, and a glass transition point of the bisphenol S-type phenoxy resin is 100-150°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insulating varnish capable of forming an insulating coating that maintains excellent adhesion with a conductor even after high-temperature treatment such as impregnation varnish treatment, and an insulated wire in which a primer layer is formed from the varnish.

  Insulation varnishes mainly composed of polyesterimide resin are used for insulated wires for motor windings and transformer windings that require high heat resistance.

  With the development of automation and high-speed winding process, the requirements for wear resistance, heat resistance, and flexibility for the insulation film of windings are becoming stricter year by year, and further, the output of various electric devices is increased or downsized. As the demand for power saving increases, the space factor increases, and the processing load applied to the windings becomes severe. Under such circumstances, various proposals have been made to improve the abrasion resistance, flexibility and adhesion of the polyesterimide resin insulation coating.

  For example, in Japanese Patent No. 3766447, metal deactivators such as acetylenes, alkynols, aldehydes, amines, mercaptans, and thioureas, phenol resins, urea resins, melamine resins, epoxy resins, silicone resins, etc. It has been proposed to improve the heat resistance of the insulating coating and the adhesion to the conductor by blending the curable resin. And in an Example, the insulation film which added 5-amino- 1,3,4-thiadiazole-2-thiol and the melamine resin to the polyesterimide-type coating material is the adhesive force by a 180 degree peeling test, after a heat shock test It disclosed that it was excellent in flexibility.

Japanese Patent No. 3766447

  However, in specifications where varnish impregnation is performed, it is not sufficient to improve adhesion at room temperature or flexibility after a heat shock test. Adhesion after heat treatment, softening resistance under high load conditions, etc. must also be satisfied.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an insulating material that has excellent adhesion to a conductor even after heat treatment and has softening resistance even under high load conditions. The object is to provide an insulating varnish capable of forming a coating.

  The present inventors have proposed an insulated wire using an epoxy resin, in particular a phenoxy resin, as a primer layer as an insulating film that can maintain adhesion with a conductor even after heat treatment (Japanese Patent Application No. 2007-266405). However, as a substitute for the polyesterimide varnish, the present invention has been reached as a result of further investigations on other characteristics.

  That is, the insulating varnish of the present invention contains 100 to 30 parts by mass of phenoxy resin of 80 to 30% by mass of bisphenol A type phenoxy resin and 20 to 70% by mass of bisphenol S type phenoxy resin, and 5 to 50 parts by mass of blocked isocyanate. The glass transition point of the bisphenol A type phenoxy resin is preferably 60 to 90 ° C, and the glass transition point of the bisphenol S type phenoxy resin is preferably 100 to 150 ° C.

  The insulated wire of the present invention has a primer layer formed by applying and baking the phenoxy resin insulating varnish of the present invention on a conductor.

  The insulating varnish of the present invention improves softening resistance under high load at high temperatures by blending two types of phenoxy resins having different glass transition points.

  Although embodiments of the present invention will be described below, it should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Phenoxy resin insulation varnish]
The phenoxy resin insulating varnish of the present invention uses a phenoxy resin of 80 to 30% by mass of a bisphenol A type phenoxy resin and 20 to 70% by mass of a bisphenol S type phenoxy resin as a coating film constituting resin, and a blocked isocyanate as a curing agent. It is characterized by.

<Phenoxy resin>
The phenoxy resin used in the present invention refers to a resin having a large molecular weight among epoxy resins produced from a bisphenol compound and epihalohydrin.

  The bisphenol A type phenoxy resin is a phenoxy resin having a bisphenol A skeleton using 2,2-bis (p-hydroxyphenyl) propane (hereinafter referred to as “bisphenol A”) as a bisphenol compound (bisphenol A type phenoxy resin). ).

  Commercially available products can be used as the bisphenol A type phenoxy resin, for example, manufactured by Toto Kasei Co., Ltd., part numbers YP-50, YP50S, YP-55, YP-70, Epicoat manufactured by Japan Epoxy Resin Co., Ltd. Examples include Epicron produced by Dainippon Ink & Chemicals, PKHC, PKHH and PKHJ produced by Union Carbide.

As the bisphenol A-type phenoxy resin, those having a weight molecular weight of 30,000 to 80,000 (measured by GPC), particularly 60000 to 80,000 are preferably used, and the glass transition point is 60 to 90 ° C. by DSC method (10 ° C./min ascending value). It is preferable.
The epoxy equivalent (JIS K7236) is preferably 10,000 to 100,000 g / eq, more preferably 50,000 to 100,000 g / eq.

  The bisphenol S-type phenoxy resin is a 2,2-bis (p-hydroxyphenyl) sulfone (hereinafter referred to as “bisphenol S”) as part of a bisphenol-based compound in order to increase the heat resistance of the bisphenol A-type phenoxy resin. Is a phenoxy resin having a bisphenol S skeleton. That is, the bisphenol S type phenoxy resin usually has a bisphenol S skeleton and a bisphenol A type skeleton.

  As the bisphenol S-type phenoxy resin used in the present invention, those having a weight molecular weight of 20,000 to 60,000 (measured by GPC), particularly 30,000 to 50,000 are preferably used, and a glass transition point of 100 by DSC method (10 ° C./min increase). It is preferable that it is -150 degreeC.

  A commercially available product may be used as the bisphenol S-type phenoxy resin, and examples thereof include product number YPS007A30A manufactured by Toto Kasei Co., Ltd.

  The above bisphenol A type phenoxy resin and bisphenol S type phenoxy resin are bisphenol A type phenoxy resin: bisphenol S type phenoxy resin (mass ratio), and are 8: 2 to 3: 7, preferably 6: 4 to 4 : Used as a phenoxy resin mixed in 6.

  The blend type phenoxy resin mixed in the above proportion has improved softening resistance as compared with the case of the bisphenol A type phenoxy resin and the bisphenol S type phenoxy resin alone. Although the reason is not clear, a blend of two types of phenoxy resins having different glass transition points and viscoelastic properties at high temperatures makes bisphenol S-type phenoxy resins having a high glass transition point act as softening-resistant resins at high temperatures. The bisphenol A-type phenoxy resin having a low glass transition point acts as an elastomer and absorbs and relaxes stress, so that it seems that the adhesion and softening resistance under high load and high temperature are maintained.

<Curing agent>
Since the phenoxy resin has a highly reactive epoxy group or hydroxyl group in the skeleton, it is preferable to coexist with a curing agent that can react with these to form a crosslinked structure.

  In the insulating varnish of the present invention, a blocked isocyanate obtained by protecting an isocyanate group of an isocyanate compound with a blocking agent is used as a curing agent. The blocked isocyanate compound is stable at room temperature, but regenerates a free isocyanate group when heated above its dissociation temperature. The dissociation temperature of isocyanate depends on the type of blocking agent, but is preferably 80 to 160 ° C, more preferably 90 to 130 ° C.

  Examples of the isocyanate compound include aromatic diisocyanates such as tolylene diisocyanate (TDI), p-phenylene diisocyanate, and naphthalene diisocyanate; carbon numbers such as hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, and lysine diisocyanate. 3-12 aliphatic diisocyanates; 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4 , 4'-diisocyanate, 1,3-diisocyanatomelylcyclohexane (hydrogenated XDI), hydrogenated TDI, 2,5-bis (isocyanatome Alicyclic diisocyanates having 5 to 18 carbon atoms such as (l) -bicyclo [2.2.1] heptane, 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane; (XDI), aliphatic diisocyanates having an aromatic ring such as tetramethylxylylene diisocyanate (TMXDI), and modified products of these diisocyanates.

  Examples of the blocking agent that blocks the isocyanate group of these isocyanate compounds include alcohols, phenols, ε-caprolactam, butyl cellosolves, and the like.

  Commercially available products may be used as the blocked isocyanate as described above, for example, CT table, Sumitomo Biurethane Co., Ltd., BL-3175, TPLS-2759, BL-4165, Nippon Polyurethane Industry Co., Ltd. MS-50, etc. be able to.

  The blocked isocyanate is used in a ratio of 5 to 50 parts by mass, preferably 10 to 40 parts by mass, per 100 parts by mass of the phenoxy resin.

<Organic solvent>
The insulating varnish of the present invention is obtained by dissolving the above phenoxy resin and blocked isocyanate in an organic solvent.
The organic solvent used in the present invention is not particularly limited as long as it can dissolve the base resin. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, tetramethyl Polar organic solvents such as urea, hexaethyl phosphate triamide, and γ-butyrolactone, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as methyl acetate, ethyl acetate, butyl acetate, and diethyl oxalate Ethers such as diethyl ester, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol methyl ether, tetrahydrofuran Hydrocarbon compounds such as hexane, heptane, benzene, toluene, xylene; halogenated hydrocarbon compounds such as dichloromethane and chlorobenzene; phenols such as cresol and chlorophenol; tertiary amines such as pyridine, and the like. A solvent can be used individually or in mixture of 2 or more types, respectively.

  The organic solvent is usually used so that the solid content in the varnish is about 30 to 60% by mass.

<Other ingredients>
The phenoxy resin insulating varnish of the present invention may contain the following components in addition to the phenoxy resin, the curing agent, and the organic solvent.
For example, as long as it does not affect the properties of the blend type phenoxy resin, it includes resins used for other insulating coatings such as phenoxy resins having other skeletons, epoxy resins, polyesterimide resins, and polyamideimide resins. It may be.

  In addition, if the curing agent other than the blocked isocyanate, for example, a methylene compound, a silane coupling agent, a titanate coupling agent, etc., is an amount that does not affect the curing system composed of the blend type phenoxy resin and the blocked isocyanate, It may be contained.

  The insulating varnish of the present invention may further contain various additives such as pigments, dyes, inorganic or organic fillers, lubricants, antioxidants, leveling agents and the like, as long as the purpose of the present invention is not impaired. It may be contained.

  The insulating varnish of the present invention having the above composition not only forms an insulating film excellent in heat resistance, flexibility and wear resistance, but also has excellent adhesion to a conductor even under stress. It can also be used as a primer layer coating for insulated wires.

  The insulating varnish of the present invention can be applied directly to a conductor and then baked and cured to form an insulating coating. The baking temperature is preferably a temperature at which the phenoxy resin can be thermally cured by reacting with the blocked isocyanate.

[Insulated wire]
The insulated wire of this invention has a primer layer formed with the hardened | cured material of the said insulating varnish of this invention on the conductor surface.

  As a conductor, it is a well-known conductor normally used for an electric wire conductor, and metal conductors, such as a copper wire and an aluminum wire, are used.

  The insulating varnish of the present invention is preferably carried out by passing it through a furnace at about 350 to 500 ° C. for 10 seconds to 30 seconds per pass (100 seconds to 300 seconds for 10 pulls).

  Although the thickness of a primer layer is not specifically limited, 1-20 micrometers is preferable, More preferably, it is 1-10 micrometers. This is because this thickness is sufficient for the primer layer.

The insulated wire of the present invention has at least one overcoat layer on the primer layer as described above.
The composition of the overcoat layer is not particularly limited, and polyesterimide resins, polyamideimide resins, polyimide resins, polyurethane resins, polyester resins, polyamide resins, phenoxy resins, and the like conventionally used for insulating coatings Can be used. The topcoat layer-constituting resin may be the same as or different from the primer layer-constituting resin, and is appropriately selected according to the use of the insulated wire.

  When the topcoat layer is composed of two or more layers, the topcoat layer of the outermost layer of the insulated wire is preferably composed of a film having lubricity, for example, a highly lubricous polyimide, a highly lubricated amideimide, or the like.

  The best mode for carrying out the present invention will be described with reference to examples. The examples are not intended to limit the scope of the invention.

[Measurement evaluation method]
First, the evaluation method performed in this example will be described.

(1) Flexibility The insulated wire was stretched by 20% with respect to the initial length, and after stretching, it was tested according to JIS C3003 7.1.1 flexibility test. Specifically, after winding the electric wire 30 times so that the electric wire and the electric wire are in contact with each other along a round bar having the self-diameter (1d) and double (2d) of the insulated electric wire, the presence or absence of cracks was observed. The diameter (1d or 2d) of the round bar when no crack occurred was examined. If no crack occurs even in 1d, it can be said that the flexibility is excellent.

(2) Heat shock test The insulated wire was stretched by 20% with respect to the initial length, and after stretching, it was tested according to the impact resistance test of JIS C3003-20. Specifically, after heating at 200 ° C. for 30 minutes, the electric wire is wound 30 times so that the electric wire and the electric wire are in contact with each other along a round bar having a self-diameter (1d) and twice (2d) of the insulated electric wire. After that, the presence or absence of cracks was observed, and the diameter of the round bar when no cracks occurred was examined. It means that the smaller the diameter of the round bar is, the higher the heat resistance is, the higher the heat resistance, and the better the heat resistance.

(3) Wear resistance The unidirectional wear value (g) was measured in accordance with the wear resistance test described in JIS C3003-1999. This is an investigation of how much force is applied to break the coating, and it is an index of coating strength against stress during shoreline.
In addition, about each insulated wire, the average value of the result of having measured 9 pieces is shown.

(4) Adhesiveness According to JIS-C3003 “8.1a) rapid extension”, film floating (average value when measured at two locations) was measured.
The measurement was performed after standing at room temperature at 160 ° C. for 6 hours, standing at 180 ° C. for 6 hours, and then standing at 200 ° C. for 6 hours.

(5) Softening resistance The softening temperature (° C.) was measured according to JIS C3003 “Test method for enameled copper wire and enameled aluminum wire”. For each of a load (700 g) and a double load (1400 g) specified in JIS, the temperature (softening temperature) when the wire was conducted was measured.
In addition, about each insulated wire, the average value of the maximum value and the minimum value of the result of measuring four each is shown.

[Phenoxy resin]
(1) Bisphenol A type phenoxy resin “YP-50” manufactured by Tohto Kasei Co., Ltd. (epoxy equivalent of 87600 g / eq based on JIS K7236, weight average molecular weight of 60000-80000 by GPC, glass by DSC method (10 ° C./min increase) Transition point 84 ° C.).

(2) Bisphenol S-type phenoxy resin “YPS-007A30” manufactured by Tohto Kasei Co., Ltd. (weight molecular weight 35000-45000 by GPC, glass transition point 130 ° C. by DSC method (10 ° C./min increase)) was used.

[Preparation of insulated varnish and production of insulated wire]
(1) Insulated wire No. 1-7
Bisphenol A type phenoxy resin and bisphenol S type phenoxy resin were blended in the proportions shown in Table 1 and dissolved in cresol / cyclohexanone. To this, blocked isocyanate (MS-50 manufactured by Nippon Polyurethane Industry Co., Ltd.) was added as a curing agent so as to be 20 parts by mass per 100 parts by mass of the phenoxy resin to prepare an insulating varnish having a solid content of 30% by mass.

The prepared insulating varnish was applied to a copper wire having a diameter of 1.0 mm to form a 3 μm primer layer (first layer).
Next, general-purpose ester imide varnish (“Isomid40SM45”, an ester imide varnish manufactured by Hitachi Chemical), general-purpose polyamide-imide varnish (“HI-406E-34” manufactured by Hitachi Chemical), self-lubricating polyamide-imide varnish (Sumitomo Electric Wintech) Co., Ltd.) were sequentially applied to form an insulating film having a thickness of 35 μm having a four-layer structure composed of a second layer (25 μm), a third layer (5 μm), and a fourth layer (2 μm).

  About the produced insulated wire, flexibility, a heat shock test, abrasion resistance, adhesion, and softening resistance were measured based on the said evaluation method. The results are shown in Table 1.

  No. About the primer layer used by 1, 4, and 7, the dynamic viscoelasticity was measured using Seiko Instruments Dynamic Mechanical Spectorscopy DMS6100 (Natural atmosphere, temperature rising rate: 10 degree-C / min, 1Hz). The results are shown in FIG. In FIG. 1, the horizontal axis is temperature (° C.), and the vertical axis is dynamic elastic modulus (MPa).

(2) Insulated wire No. 8, 9
As a reference example, an insulated wire was used except that a primer layer was formed using a commercially available highly adhesive ester imide varnish (“EH402-45” manufactured by Dainichi Seika) and a general-purpose ester imide varnish (“Isomid 40SM45” manufactured by Hitachi Chemical). No. 1 and the flexibility, heat shock test, wear resistance, adhesion, and softening resistance were measured based on the above evaluation methods. The results are shown in Table 1.

When only a bisphenol A type phenoxy resin is used as the coating film forming resin (No. 1), all of the flexibility, heat shock test, wear resistance, adhesion at normal temperature and high temperature treatment, and heat resistance than before When the polyesterimide resin varnish used in No. 8 or 9 was used, the results were comparable or excellent, but the softening resistance at JIS double load was poor.
By using a phenoxy resin blended with 25 to 60% by mass of bisphenol S-type phenoxy resin (No. 2 to 5), flexibility in the case of only bisphenol A-type phenoxy resin (No. 1), heat shock test, It was found that the softening temperature under JIS double load can be improved without affecting the wear resistance, adhesion at normal temperature and after high temperature treatment. On the other hand, when only the bisphenol S-type phenoxy resin is used (No. 7), when the content of the bisphenol S-type phenoxy resin in the coating film-forming resin is 75% by mass (No. 6), In addition to the improvement in softening resistance, a significant decrease was observed in the adhesion after high-temperature treatment. It can be seen that it is useful to use a film-forming resin obtained by blending a bisphenol S-type phenoxy resin and a bisphenol A-type phenoxy resin at a specific ratio.

  From FIG. 1, the blend phenoxy resin (No. 4: triangle mark) of bisphenol A type and bisphenol S type is No. 1 (diamond mark), No. 1 Compared to 7 (square mark), it can be seen that the decrease in dynamic elastic modulus at a high temperature is moderate. It is inferred that the gradual decrease in the high temperature dynamic modulus of the blend type contributes to the improvement of the softening resistance under JIS double load.

  As an alternative to a polyesterimide resin varnish, it is also useful as an insulated wire for winding that is subjected to high temperature treatment and varnish impregnation treatment as a use that has been insufficient with conventional polyesterimide resin varnishes.

No. It is a graph which shows the measurement result of the dynamic viscoelastic property of the primer layer (1st layer film) of 1, 4, and 7.

Claims (3)

A phenoxy resin insulating varnish containing 100 to 30 parts by mass of phenoxy resin of 80 to 30% by mass of bisphenol A type phenoxy resin and 20 to 70% by mass of bisphenol S type phenoxy resin, and 5 to 50 parts by mass of blocked isocyanate. 2. The phenoxy resin insulating varnish according to claim 1, wherein the bisphenol A type phenoxy resin has a glass transition point of 60 to 90 ° C., and the bisphenol S type phenoxy resin has a glass transition point of 100 to 150 ° C. 3. The insulated wire which has a primer layer formed by apply | coating and baking the phenoxy resin insulation varnish of Claim 1 or 2 on a conductor.

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