JP5704494B2 - Insulated wire - Google Patents

Description

  The present invention relates to an insulated wire that is suitably used in an electric device, a compressor, or the like in which a refrigerant is used, such as an air conditioner or a refrigerator.

  Since an insulated wire is used in various modes depending on the type of electrical equipment, an insulating coating having excellent adhesion is required so that insulation can be ensured in various specification modes. For example, it is required that the film does not peel off even against mechanical and physical stimuli such as wear and scratches.

  As an insulating film having excellent adhesion, insulation, and mechanical strength, for example, in Japanese Patent Application Laid-Open No. 2007-287399 (Patent Document 1), the insulating film has a two-layer structure, the first insulating layer is polyesterimide, An insulated wire in which the second insulating layer is made of polyamideimide has been proposed.

JP 2007-287399 A

By the way, electrical products such as air conditioners and refrigerators that use refrigerants, especially insulated wires used in compressors, have excellent adhesion to mechanical and physical stimuli such as processing and friction as described above. It is not enough to have it.
For example, an air conditioner that is used in summer and not used in winter, particularly a compressor, resumes operation after being idle for a few months or longer. In insulated wires that are exposed to a refrigerant atmosphere, the refrigerant such as Freon that has adhered to the insulation film penetrates into the film during the resting state, and the insulation wire atmosphere is rapidly heated by restarting the equipment. Then, since the expanded and vaporized refrigerant spreads the coating, a state where the insulating coating is foamed, that is, a blister is generated. Such a foaming phenomenon may occur even when a film with increased conductor adhesion to mechanical and physical stimuli is used. For example, it is not possible to determine whether or not it can be used only by simple adhesion evaluation.

  On the other hand, polyesterimide resin insulation films are excellent in solvent resistance and have few problems of blistering, and are therefore used as insulation wire films for air conditioners and air conditioners. However, in order to cope with the severe winding process and varnish impregnation treatment in recent years, demands for heat resistance and wear resistance are becoming stricter year by year. For this reason, it is necessary to comprehensively evaluate wear resistance, heat resistance, adhesion, blister generation, etc., as a coating for insulated wires used in air conditioners and compressors. Insulated wires that can satisfy these characteristics in a composite manner Is required.

  The present invention has been made in view of such circumstances, and the object of the present invention is not only the adhesiveness to mechanical stimulation, but also when the operation is resumed after being exposed to a refrigerant for a long time. It is in providing the insulated wire which can suppress generation | occurrence | production of a blister.

  The present applicant has found that an insulated wire using a cured product of an epoxy resin as a primer layer is superior in adhesion after heating and wear resistance as compared with an esterimide insulating coating, and applied for a patent (Japanese Patent Application No. 2007- 266405). Further studies were made to complete the present invention so that the suppression of blister generation could be satisfied.

  That is, the insulated wire of the present invention includes a conductor; an epoxy resin, and a base layer that covers the conductor, which is composed of a cured resin composition containing a hydroxyl group-containing xylene / formaldehyde resin; and the base layer In the insulated wire having the formed insulating layer, the xylene / formaldehyde resin is contained in an amount of 1 to 10 parts by mass per 100 parts by mass of the epoxy resin.

It is preferable that the number-average molecular weight before Symbol xylene-formaldehyde resin is 100 to 3,000. Furthermore, it is preferable that 5-30 mass parts of blocked isocyanate is contained per 100 mass parts of the epoxy resin. The epoxy resin is preferably a phenoxy resin.

  The insulating layer is preferably made of a polyesterimide resin, and it is preferable that a lubricating overcoat layer is further formed on the insulating layer.

  In the insulated wire of the present invention, the base layer is composed of a cured product of a resin composition containing an epoxy resin and a xylene / formaldehyde resin having a hydroxyl group. In addition, the suppression of blistering can also be satisfied.

  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.

  The insulated wire of the present invention comprises a conductor; a cured product of a resin composition containing a thermosetting resin having a reactive functional group, such as an epoxy resin and a xylene / formaldehyde resin having a hydroxyl group. A base layer to be coated; and an insulating layer formed on the base layer. Hereinafter, each will be described in order.

〔conductor〕
A metal conductor such as a copper wire or an aluminum wire is used as the conductor.

[Underlayer]
The underlayer is composed of a cured product of a resin composition containing an epoxy resin and a thermosetting resin having a reactive functional group. In particular, it is preferably composed of a cured product of a resin composition containing an epoxy resin and a xylene / formaldehyde resin having a hydroxyl group, and further composed of a cured product of a resin composition containing a blocked isocyanate. preferable.

<Epoxy resin>
Examples of the epoxy resin used in the present invention include an epoxy resin produced from bisphenol and epihalohydrin, an epoxy resin obtained by subjecting a phenol epoxy resin and bisphenol to an addition polymerization reaction, and the like. Or a mixture of two or more. Among these, an epoxy resin produced from bisphenol and epihalohydrin is preferable, and a phenoxy resin having a large molecular weight is more preferable.

  Examples of bisphenol include 2,2-bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) sulfide, and 2,2-bis. (4-Hydroxyphenyl) sulfone, 3,4,5,6-dibenzo-1,2-oxaphosphane-2-oxide hydroquinone and the like may be mentioned, and these may be used alone or in combination of two or more. it can. A suitable representative example of epihalohydrin is epichlorohydrin.

  Suitable epoxy resins produced from bisphenol and epihalohydrin include, for example, bisphenol A phenoxy resin produced from bisphenol A and epihalohydrin, and bisphenol S phenoxy resin produced from bisphenol S and epihalohydrin. . These phenoxy resins are all commercially available compounds, and specific examples include product numbers YP-50, YP50S, YP-55, YP-70, and YPS007A30A manufactured by Tohto Kasei Co., Ltd. However, the present invention is not limited to such examples.

  Although the weight average molecular weight of the epoxy resin used for this invention is not specifically limited, From a viewpoint of improving heat resistance and adhesiveness, Preferably it is 30000-100000, More preferably, it is 50000-80000.

<Heat-curing resin>
The thermosetting resin used for the underlayer of the present invention is a thermosetting resin that has a reactive functional group such as a hydroxyl group such as an amino group or a methylol group and can be cured by heating. Specifically, phenol resins obtained by reaction of phenols with aldehydes, amino resins obtained by condensation of amino group-containing compounds and formaldehyde, xylene / formaldehyde resins having hydroxyl groups, or mixed resins thereof are used. It is done.

  Examples of amino group-containing compounds used for the synthesis of amino resins include urea, alkylurea, melamine, acetoguanamine, aniline, benzoguanamine and the like. Accordingly, the amino resin used in the present invention is a condensate of these amino group-containing compounds and formaldehyde, or an alcohol-modified resin thereof, and examples thereof include urea resins, melamine resins, guanamine resins, urea-melamine resins, and the like. .

  As such an amino resin, a commercially available product may be used, and specifically, Mitsui Chemical Co., Ltd. Euban 10S-60, 10R, 20SB, 20SE-60, 20HS, 21HV, 21R, 22R, 22R-60. 120, 122, 220, 134, 135, 136, 60R, 62, 69-1, 163, 164, 165, 805, 91-55; Cymel 300, 301, 303, 325, 350, Nippon Cytec Industries, Ltd. 370, 1116, 1130, 1123, 1125; DIC Corporation Becamine P-138, P-196-M, G-1800, G-1850, Super Becamine OD-L-131-60, L-806, J- 820-60, L-109-65, L-117-60, L-127-60, G-821-60, -101-60, 47-508-60, L-116-70, L-118-60, L-121-60, L-120-60, TD-139, 17-590, L-105-60, TD -126, P-198.

  Such an amino resin has an alcoholic hydroxyl group or an amino group as a reactive functional group at the resin terminal by a methylolation reaction, and can be cured by normal temperature to heating.

  When an amino resin having a reactive hydroxyl group such as a methylol group contains an epoxy resin and a blocked isocyanate by heating, it is considered that it can further react with an isocyanate group to form a crosslinked cured product. Thereby, it is thought that it can be useful for the modification of the epoxy resin. In particular, the occurrence of blistering at a high temperature, which was a weak point of phenoxy resin, can be suppressed. In curing the epoxy resin, it is possible to prevent the penetration of the refrigerant by forming a cured body film having a cross-linked structure in which the amino resin is also involved, and for the penetrated refrigerant, the swelling of the film due to the vaporization of the refrigerant is suppressed, and the refrigerant As a result, it can be considered that the occurrence of blisters can be suppressed by preventing the omission of omission.

  Examples of phenols used for the synthesis of phenol resins include alkylphenols such as cresol, xylenol and isopropylphenol; divalent phenols such as resorcin; vinylphenols such as p-vinylphenol, etc. Two or more kinds may be used in combination. Examples of aldehydes used in the synthesis of phenol resins include aldehyde group-containing compounds such as acetaldehyde and furfural in addition to formaldehyde, and these can be used in combination of two or more. Depending on the types of phenols and aldehydes used, phenol resins are known as phenol resins, xylene resins, resorcin resins, resorcin-modified phenol resins, cresol-modified phenol resins, alkylphenol-modified resins, and the like.

  Such phenol resins are generally classified into a novolak type synthesized using an acid catalyst and a resol type synthesized using an alkali catalyst. In the present invention, a reactive hydroxyl group is attached to the end of the resin chain. In particular, a resol type having a methylol group is preferably used.

  Commercially available products may be used as the phenolic resins, for example, Sumikanol 610 from Taoka Chemical Co., Ltd .; Tamanoru 1010R, Tamanoru 100S, Tamanoru 510, Tamanoru 7509, Tamanoru 7705 from Arakawa Chemical Industries, Ltd .; Showa Polymer Shounol CKM-1634, 1636, 1737, 1282, 904, 907, 908, 983, 2400, 941, 2103, 2432, 5254, BKM-2620, BRP-5904, RM-0909, BLS-2030 3574, 3122, 362, 356, 3135, CLS-3940, 3950, BRS-324, 621, BLL-3085, BRL-113, 114, 117, 134, 274, 2584, 112A, 120Z, CKS-3898; SP-460B, SP103H, HRJ-1367 from Gee Chemical Co., Ltd .; Resist Top PL2211, from Gunei Chemical Industry Co., Ltd .; PR-HF-3, PR-53194, PR-53195 from Sumitomo Bakelite Co., Ltd .; Nikanol PR1440 from Fudo Co., Ltd. , Nikanol L, Nikanol P100; Plyofen 5010, 503 and TD-447 manufactured by DIC Corporation.

  The above phenol resins are room temperature liquid resins and can be cured by heating. Moreover, since it has an alcoholic hydroxyl group such as methylol as a reactive functional group, it reacts with an isocyanate when it contains an epoxy resin contained in the varnish and further a blocked isocyanate to form a crosslinked cured product. It is thought that this can be useful for the modification of the epoxy resin. That is, the blister generation at a high temperature, which is a weak point of the phenoxy resin, can be suppressed similarly to the amino resin. Furthermore, phenol resins can effectively suppress the occurrence of blisters without impairing the excellent wear resistance, softening resistance, and high-temperature adhesion of phenoxy resins.

  The above amino resins and phenol resins may be used alone, in combination of two or more kinds, or as a blend resin of an amino resin and a phenol resin. Phenol resins are preferred.

  Furthermore, among the phenolic resins, liquid modified xylene / formaldehyde resins obtained by reacting xylene / formaldehyde resins obtained by the reaction of xylene and formaldehyde with addition of alcohols and phenols in the presence of an acidic catalyst. Specifically, an oligomer having a methylol group as a reactive hydroxyl group is preferably used in a resol type resin containing a metaxylene / mesitylene skeleton. It is preferable that the number average molecular weight of the said oligomer is 100-3000, More preferably, it is an oligomer of about 200-1500. Moreover, it is preferable that it is a liquid with a viscosity of 20-15000 centipoise (25 degreeC) so that it may be excellent in compatibility with an epoxy resin, More preferably, it is 30-5000 centipoise (25 degreeC), More preferably, it is 30-1000 centipoise. Particularly preferred is 30 to 500 centipoise.

  The thermosetting resin having such a reactive functional group is contained in an amount of 1 to 10 parts by mass, preferably 2 to 8 parts by mass, per 100 parts by mass of the epoxy resin. When the content is too large, the crosslink density of the film becomes too high, the flexibility is lowered, the elongation of the film is lowered, and the film adhesion during processing and use is lowered. On the other hand, if the amount is too small, it is difficult to obtain the effect of adding the thermosetting resin, that is, the effect of suppressing the generation of blisters.

<Block isocyanate>
The underlayer resin composition preferably contains a blocked isocyanate. The blocked isocyanate mainly acts as a curing agent for the epoxy resin.

  Examples of the isocyanate compound include aromatic diisocyanates such as tolylene diisocyanate (TDI), p-phenylene diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, and the like. Aliphatic diisocyanates having 3 to 12 carbon atoms: 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene Dicyclohexyl-4,4′-diisocyanate, 1,3-diisocyanatotomylcyclohexane (hydrogenated XDI), hydrogenated TDI, 2,5-bis (iso Alicyclic diisocyanates having 5 to 18 carbon atoms such as natomethyl) -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); modified products of these diisocyanates, and the like can be used alone or in combination of two or more.

  What is marketed as a block isocyanate hardening | curing agent may be used, for example, using CT table of Sumitomo Biurethane, BL-3175, TPLS-2759, BL-4165, MS-50 by Nippon Polyurethane Industry, etc. Can do.

  Such a blocked isocyanate compound is preferably used at a ratio of 5 to 30 parts by mass per 100 parts by mass of the epoxy resin. The blocked isocyanate compound can form a bond with a curing agent of an epoxy resin, and further with a thermosetting resin having a reactive functional group, and by these reactions, a highly three-dimensional reticulated cured body is formed. A coating film can be provided, and the heat resistance, wear resistance, softening resistance, and adhesion of the base layer based on the epoxy resin, and thus the coating film, can be increased, and blistering can be suppressed.

  In the resin composition constituting the base layer of the insulated wire of the present invention, in addition to the epoxy resin, thermosetting resin, and blocked isocyanate, as long as the purpose of the present invention is not impaired, for example, silica, Fillers such as alumina, magnesium oxide, beryllium oxide, silicon carbide, titanium carbide, tungsten carbide, boron nitride, silicon nitride; to improve insulating paint curability and fluidity, for example, tetraisopropyl titanate, tetrabutyl titanate, tetra Additives such as titanium compounds such as hexyl titanate and zinc compounds such as zinc naphthenate and zinc octenoate; antioxidants; curability improvers; leveling agents;

  An undercoat layer is formed by applying a paint obtained by diluting a resin composition containing the above components with an organic solvent as appropriate to the conductor surface, followed by heat curing. Although heating temperature is not specifically limited, It is preferable that it is about 100-250 degreeC.

  In addition, as an organic solvent used for preparation of a coating material, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, hexaethyl phosphate triamide, γ -Polar organic solvents such as butyrolactone, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; esters such as methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate; diethyl ester, ethylene glycol dimethyl ether, Ethers such as diethylene glycol monomethyl ether, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol methyl ether, tetrahydrofuran; hexane, heptane, benzene, toluene Hydrocarbon compounds such as ene and xylene; halogenated hydrocarbon compounds such as dichloromethane and chlorobenzene; phenols such as cresol and chlorophenol; tertiary amines such as pyridine, and the like. Or 2 or more types can be mixed and used.

  Although it does not specifically limit as thickness of a base layer, From a viewpoint of improving the adhesiveness of an insulating film and a conductor, Preferably it is 1.0-10 micrometers, More preferably, it is 1.0-5 micrometers.

[Insulating layer]
As the insulating layer, resins, polyester imides, polyimides, polyamide imides, and the like conventionally used as insulating coatings can be used. Of these, polyester imide is preferable.

  As a method for forming the insulating layer, for example, a resin composition obtained by adding, to the polyesterimide resin, additives such as those listed in the composition for the underlayer, as necessary, within a range not impairing the object of the present invention. It can be formed by applying a coating solution for an insulating film obtained by dissolving an object in an organic solvent on the base layer. Or you may form by drying, after immersing the electric wire in which the base layer was formed in the coating liquid for insulating films.

  The insulating layer may be formed from one layer or may be formed from two or more layers. When composed of two or more layers, they may be composed of a combination of different resins, for example, a polyesterimide layer and a polyamideimide layer.

  The thickness of the insulating layer is preferably 1 to 100 μm, more preferably 10 to 50 μm, from the viewpoint of protecting the conductor. This is because if the insulating coating becomes too thick, the outer diameter of the insulated wire increases, and as a result, the space factor of the coil in which the insulated wire is wound tends to decrease.

(Lubricity overcoat layer)
In the insulated wire of the present invention, it is preferable that a lubricating overcoat layer is further formed on the insulating layer. It is preferable to coat the insulating layer with a resin having lubricity because friction between the electric wires can be reduced at the time of compression processing for increasing coil winding or space factor.

  The resin constituting the lubricity overcoat layer may be any resin that has lubricity, for example, paraffins such as liquid paraffin and solid paraffin, various waxes, polyethylene, fluororesin, silicone resin and other lubricants as binders. Examples thereof include those bound with a resin. Preferably, an amidoimide resin imparted with lubricity by adding paraffin or wax is used. The lubricity overcoat layer may be formed not only by the resin having the above-mentioned lubricity but also by applying a non-volatile lubricant.

  The lubricating overcoat layer may be composed of one layer or may be composed of two or more layers. Moreover, you may form by apply | coating a non-volatile lubricating oil on the resin layer which has lubricity, and also on it.

  The thickness of the lubricating overcoat layer is not particularly limited, but may be any thickness that is necessary and sufficient to reduce friction and wear with the surrounding electric wires when it is formed into a coil. 10 μm is preferable, and more preferably 1 to 5 μm.

  The insulated wire of the present invention having the configuration as described above has not only excellent insulation against mechanical stimulation but also specifications that are exposed to a refrigerant atmosphere, and after operation for a certain period of time, The generation of blisters is also suppressed in specifications where operation and pause such as pausing for a certain period are repeated alternately.

  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) Flexible The insulated wire was stretched by 30% 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 10 times so that the electric wire and the electric wire were in contact with each other along a round bar having a self-diameter of the insulated wire, the presence or absence of cracks was observed and the number of cracks was counted.

(2) Dielectric breakdown voltage (kV)
It measured based on JIS C3003 10.2.2. Specifically, after immersing an electric wire 25 cm in a glycerin / saturated NaCl water = 85/15 solution and immersing a copper plate as a counter electrode, the wire conductor is a positive electrode, the copper plate is a negative electrode, and the waveform is close to a 50 Hz sine wave. An alternating voltage was applied, the voltage was increased at a speed of 500 V / s, and the voltage when current flowed was measured.
(3) Friction resistance (gf)
JIS C3003 9. The unidirectional wear test was conducted.

(4) Adhesiveness i) Initial adhesiveness Conductor length exposed by cutting the produced insulated wire by rapid extension according to JIS C3003 “8.1a) Rapid extension, and peeling off the coating at the cut part. The average value (measured at two places: conductor exposure average (mm)) was measured. As the measured value is smaller, the coating layer is not peeled off even on the rapidly extending cut surface, indicating that the adhesiveness is excellent.

ii) Adhesiveness after heat treatment After the insulated wire was heated at 180 ° C. for 6 hours (heating condition 1) or 160 ° C. for 6 hours (heating condition 2), it was exposed according to the initial adhesiveness of i) above. The conductor length (mm) was measured in the same manner.

(5) Blister after refrigerant treatment The insulated wire was immersed in refrigerant R22 (Daikin 22 of Daikin Industries, Ltd.) (85 ° C., 42 kg / cm ² ) for 96 hours, then taken out, and rapidly removed at a predetermined temperature (120 ° C., 130 ° C. and 140 ° C.), and the foamed state of the insulated wire surface was confirmed. The case where foaming was not recognized was defined as “OK”, and the case where foaming was observed was defined as “blister generation”.

(6) Softening resistance The softening temperature (° C.) was measured according to JIS C3003 “11.1A”.

[Insulated wire No. 1 to 8]
By forming a coating having a layer structure (1st to 4th layers in order from the copper wire) having a resin wire as a main component as shown in Table 1 with a copper wire having a diameter of 0.897 to 0.898 mm, a finished outer diameter Insulated wire No. 0.966-0.969 mm 1-8 were produced. No. 3 to 8 are cases in which a phenoxy resin was used as the base resin of the first layer and a resin composition to which a xylene / formaldehyde resin and / or a curing agent (block isocyanate) was added as shown in Table 2 was used.

Specific materials used are as follows.
(1) Esterimide resin (EI)
A commercially available polyesterimide (manufactured by Hitachi Chemical Co., Ltd., trade name: Isomid 40SM-45) was used.
(2) Close contact ester imide resin (Close contact EI)
EH402-45No. 3 (manufactured by Dainichi Seika Co., Ltd.) was used.
(3) Amidoimide resin (AI)
HI-406E-34 (trade name of Hitachi Chemical Co., Ltd.) was used.

(4) Lubricating amidoimide resin (lubricating AI)
In a 1 L flask equipped with a thermometer, a cooling tube, a calcium chloride-filled tube, a stirrer, and a nitrogen blowing tube, while flowing 150 mL of nitrogen gas from the nitrogen blowing tube per minute, 176.9 g of trimellitic anhydride, 1.95 g of trimellitic acid and 232.2 g of methylene diisocyanate (trade name: Coronate PH manufactured by Mitsui Takeda Chemical Co., Ltd.) were added.
Next, 536 g of N-methyl-2-pyrrolidone as a solvent was added to the flask, heated at 80 ° C. for 3 hours while stirring with a stirrer, and then the temperature in the system was increased to 120 ° C. over about 4 hours. Warm and heat at the same temperature for 3 hours. Thereafter, the heating was stopped, and 134 g of xylene was added to the flask to dilute the content liquid, followed by cooling to obtain a general-purpose amideimide resin (AI) having a nonvolatile content of 35% by mass. Lubricating amideimide resin (lubricating AI) was obtained by mixing AI and polyethylene wax at a ratio of 1.5 parts by weight of polyethylene wax with respect to 100 parts by weight of solid content of this general-purpose amideimide resin (AI). .

(5) Phenoxy resin (PH)
A bisphenol A type phenoxy resin [Toto Kasei Co., Ltd., product name: YP-50, a solution of phenoxy resin dissolved in cresol / cyclohexanone (solid content: 27 mass%)] was used as an epoxy resin.

(6) Xylene / formaldehyde resin Nikanol PR-1440 (trade name) manufactured by Fudou Co., Ltd. was used. This is a solution (resin content: 52 mass%) of a resol type modified xylene resin (number average molecular weight 911) represented by the following formula dissolved in n-butanol, and has a viscosity of 100 to 300 centipoise (20 ° C.).

(7) Block isocyanate The block isocyanate (MS-50: brand name) of Nippon Polyurethane Industry Co., Ltd. was used. This blocked isocyanate is a bifunctional type having two isocyanate groups in one molecule.

  About each produced insulated wire, according to the said evaluation method, initial adhesiveness was measured, and after performing heat processing (heating conditions 1: 180 degreeC x 6 hours), adhesiveness was measured. Furthermore, the heat-treated electric wires were examined for flexibility, dielectric breakdown voltage, abrasion resistance, softening resistance, and occurrence of blisters after refrigerant treatment according to the above evaluation methods. The results are shown in Table 2.

  No. 1 in which the base resin of the underlayer is phenoxy resin. All of Nos. 3 to 8 were able to ensure excellent adhesion after the heat treatment. No. 3-8, the initial adhesiveness tends to be inferior to that of the ester imide resin (N.1, 2), but after the heat treatment, the adhesiveness is higher than that of the film having the base layer based on the ester imide resin. It was excellent. Moreover, it turns out that the base layer (No. 3-8) based on a phenoxy resin is excellent also in abrasion resistance, and the film excellent in mechanical strength is obtained.

  No. 3 and no. From the comparison with 4-8, even if the adhesion after rapid extension is similar, in the case of an underlayer that does not contain xylene / formaldehyde resin, the blister is In contrast to the generated (No. 3), in the case of the base layer containing xylene / formaldehyde resin, it was possible to prevent the generation of blisters. In addition, it can be seen that the inclusion of xylene / formaldehyde resin eliminates the occurrence of cracks after the flexibility test, improving the flexibility.

  No. 4-7 and no. From the comparison with Fig. 8, the phenoxy resin composition containing a curing agent improved the softening resistance, probably because a more dense coating with a three-dimensional network was obtained. The more it was, the bigger it was.

[Insulated wire No. Production of 11-24]
As shown in Table 3, instead of xylene / formaldehyde resin, a coating for the underlayer using other phenolic resins (F1 to F6) and / or amino resins (A1 or A2) is applied and heated at 400 ° C. It hardened | cured and formed the base layer (1st layer). Then, No. The second layer, the third layer, and the fourth layer are formed in the same manner as in FIG. Created 11-19,
Furthermore, except that the blocked isocyanate was changed to Bayer's "Desmodur CT" (a trifunctional type having three isocyanate groups in one molecule. Indicated as "CT" in Table 3). In the same manner as in No. 11 or 13, each insulated wire No. 20 and 21 were produced.
For reference, an insulated wire in which a base layer was formed using a phenoxy resin (No. 22), a high adhesion ester imide resin (No. 23), and a general-purpose ester imide resin (No. 24) was prepared.
Created insulated wire No. About 11-24, based on the said evaluation method, abrasion resistance, a dielectric breakdown voltage, softening resistance, adhesiveness after a heating (heating conditions 2: 160 degreeC x 6 hours), and the blister were measured. The results are shown in Table 3.

The amino resins and phenol resins in Table 3 are as follows.
A1: Cymel 370 from Nippon Cytec Industries, Ltd.
A2: Super Becamine OD-L-131-60 from DIC Corporation
F1: Sumikanoru 610 from Taoka Chemical Co., Ltd.
F2: CKS3898 of Showa Polymer Co., Ltd.
F3: PRIOFEN 5010 from DIC Corporation
F4: Gunei Chemical Industry Co., Ltd. cash register top PL2211
F5: Tamanol 100S from Arakawa Chemical Co., Ltd.
F6: PR-53194 from Sumitomo Bakelite Co., Ltd.

  When the general-purpose ester imide resin was used as the base resin for the underlayer (No. 23), the wear resistance was inferior, and when the high adhesion ester imide resin was used (No. 24), the high-temperature adhesion was inferior. On the other hand, when the phenoxy resin was used as the base resin (No. 22), all of abrasion resistance, softening resistance, and high temperature adhesion could be satisfied, but blistering occurred. However, when an amino resin (No. 11, 12, 20) or a phenol resin (No. 13-18, 21) or a blend of an amino resin and a phenol resin (No. 19) is added, blisters are generated. As with xylene / formaldehyde resins, it was confirmed that the amino resin and other phenolic resins have the effect of suppressing blister generation, which was a weak point of the phenoxy resin.

  However, when the amino resin is used (No. 11, 12, 19, 20), the phenol resin is used (No. 13 to 18), and when the phenoxy resin is used alone (No. 22), the adhesion is higher. A tendency to be slightly inferior was observed. And No. 11 and no. From the comparison of 20, even if it changed to trifunctional type as blocked isocyanate, the effect was not recognized so much for the fall suppression of high temperature adhesiveness. From these facts, it is understood that phenol resins are more effective in preventing blister generation of phenoxy resin.

  The insulated wire of the present invention not only has improved mechanical strength and high adhesion to mechanical stimulation compared to conventional wires, but also can suppress the occurrence of blisters even in an environment exposed to a refrigerant atmosphere. It is particularly useful as an insulated wire that requires process resistance, strength, and refrigerant resistance, such as a compressor coil.

Claims (6)

A conductor; an epoxy resin and a base layer covering the conductor composed of a cured product of a resin composition containing a xylene / formaldehyde resin having a hydroxyl group; and an insulated wire having an insulating layer formed on the base layer Because
The xylene / formaldehyde resin is an insulated wire containing 1 to 10 parts by mass per 100 parts by mass of the epoxy resin. The insulated wire according to claim 1, wherein the xylene / formaldehyde resin has a number average molecular weight of 100 to 3,000. Furthermore, the insulated wire of Claim 1 or Claim 2 containing 5-30 mass parts of blocked isocyanate per 100 mass parts of said epoxy resins. The insulated wire according to any one of claims 1 to 3 , wherein the epoxy resin is a phenoxy resin. The insulated wire according to any one of claims 1 to 4 , wherein the insulating layer is made of a polyesterimide resin. The insulated wire according to any one of claims 1 to 5 , wherein a lubricating topcoat layer is further formed on the insulating layer.