Polyurethane modified epoxy water-based self-adhesive insulating varnish for enameled wire and preparation method and application thereof

Abstract

The present invention relates to a polyurethane modified epoxy water-based self-adhesive insulating varnish for enameled wire and a preparation method and application thereof. The water-based self-adhesive insulating varnish is prepared from the following raw materials: modified epoxy resin, water-based polyurethane resin, wetting agent, deionized water; the modified epoxy resin is prepared by mixing and dissolving bisphenol A type epoxy resin, phenolic epoxy resin, and solvent A at 130°C, then dropping into mixture B, mixing reaction, then cooling to 60°C, adding diethanolamine for mixing reaction, finally adding deionized water, stirring and dispersing evenly, cooling to 50°C and filtering, and the water-based polyurethane resin is a water-based polyurethane resin with an unblocking temperature of 70-110°C. The water-based self-adhesive insulating varnish of the present invention is environmentally friendly and safe, can be quickly cured at 280 degrees, and the obtained coating flexibility, adhesion and electrical properties are also significantly improved, wherein the self-adhesive force at 150 degrees for 30 minutes is greater than 2.1N, which is nearly 7 times the national standard of oiliness.

Description

Technical Field

[0001] The invention belongs to the field of self-adhesive water-based self-adhesive insulating varnish for wires, and specifically relates to a polyurethane-modified epoxy water-based self-adhesive insulating varnish for enameled wires, and a preparation method and application thereof. Background Art

[0002] Enameled wire is a main type of winding wire, generally composed of three parts: conductor, insulating bottom layer and self-adhesive insulating surface layer. Its application areas include inductor coils, electromagnetic coils, AC and DC motors, automotive industry, etc. Enameled wire is mostly used for high-power and high-load motors. Under AC high frequency and high voltage, the polymer of the insulating paint film is prone to local ionization. When the electric field strength reaches the critical field strength, the nearby gas will be locally ionized, blue fluorescent discharge will occur, and ozone will be produced at the same time. Therefore, it is necessary to have good weather resistance, wear resistance, adhesion, and insulation. According to the insulating material, the existing self-adhesive enameled wires include acetal enameled wire, polyester enameled wire, polyurethane enameled wire, modified polyester enameled wire, polyesterimide enameled wire, polyesterimide / polyamideimide enameled wire, polyimide enameled wire, etc.

[0003] Among them, for traditional polyurethane enameled wires, most of them are coated with oily polyurethane insulating varnish, which is not environmentally friendly, and the resulting coating is brittle and has low self-adhesiveness. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention synthesizes a water-based polyurethane resin to provide a polyurethane-modified epoxy water-based self-adhesive insulating varnish for enameled wire and a preparation method and application thereof, which can significantly improve the flexibility, adhesion and electrical properties of the self-adhesive insulating layer while being environmentally friendly.

[0005] The present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a polyurethane modified epoxy water-based self-adhesive insulating varnish for enameled wire, wherein the water-based self-adhesive insulating varnish is prepared from the following raw materials: modified epoxy resin, water-based polyurethane resin, wetting agent, and deionized water; wherein the modified epoxy resin is prepared by the following method: bisphenol A type epoxy resin, phenolic epoxy resin, and solvent A are mixed and dissolved at 130°C, then dropwise added to mixture B, mixed and reacted, then cooled to 60°C and diethanolamine is added for mixed reaction, finally deionized water is added, stirred and dispersed evenly, cooled to 50°C and filtered; the solvent A is one or more of diethylene glycol monobutyl ether, isomers of diethylene glycol monobutyl ether, and ethylene glycol monobutyl ether; the mixed solution B is a mixture of phosphoric acid and ethylene glycol monobutyl ether;

[0007] The waterborne polyurethane resin is a waterborne polyurethane resin with a deblocking temperature of 70-110°C.

[0008] In some embodiments, the water-based self-adhesive insulating varnish is prepared from the following raw materials in weight percentage: 60-80% modified epoxy resin, 3-8% water-based polyurethane resin, 0-1% wetting agent, and the balance deionized water.

[0009] In some embodiments, the wetting agent is BYK349.

[0010] In some embodiments, the waterborne polyurethane resin is an aromatic waterborne polyurethane resin.

[0011] In some embodiments, during the preparation of the modified epoxy resin, the mass ratio of bisphenol A epoxy resin: novolac epoxy resin: solvent A: mixed solution B: deionized water = 30-40: 6-10: 20-30: 4-5: 30-40.

[0012] In some embodiments, the bisphenol A epoxy resin used in the preparation process of the modified epoxy resin is one or more of E20\E12\E06 epoxy resins.

[0013] In some embodiments, the phenolic epoxy resin used in the preparation of the modified epoxy resin is 638s epoxy resin.

[0014] In some embodiments, in the mixed solution B, phosphoric acid:ethylene glycol monobutyl ether=1:1-3.0, and the phosphoric acid is 85 wt % phosphoric acid.

[0015] In some embodiments, the modified epoxy resin has a viscosity of 4000-60000 mPa·s, a solid content of 38-40%, and a pH of 7.0-9.0.

[0016] In another aspect of the present invention, the application of the water-based self-adhesive insulating varnish is provided, wherein the water-based self-adhesive insulating varnish is coated on the surface of the wire through an enameling wire machine, with a line speed of 70-300 m / min, a curing temperature of 220-280° C., and an annealing temperature of 420-480° C. In some preferred embodiments, the line speed is 170 min, the curing temperature is 260° C., and the annealing temperature is 400° C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention improves the preparation method of epoxy resin and combines water-based polyurethane resin to prepare water-based, environmentally friendly self-adhesive wire polyurethane modified epoxy water-based self-adhesive insulating paint; the water-based self-adhesive insulating paint is non-flammable and non-explosive, safe, environmentally friendly, has a low VOC formula, and does not volatilize irritating odor; and the coating curing temperature is 100 degrees lower than the oil curing temperature, and can be quickly cured within 260 degrees. The coating has good flexibility, no pinholes, high pressure resistance, and good self-adhesion. The self-adhesive strength at 150 degrees for 30 minutes is greater than 2.1N, which is nearly 7 times the national standard of oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a picture of an enameled wire machine in an application example of the present invention;

[0020] Figure 2 This is a picture of the coated enameled wire in the application example of the present invention;

[0021] Figure 3 This is a picture of the modified resin of Example 2 of the present invention;

[0022] Figure 4 This is a picture of the self-adhesive insulating paint of Example 4 of the present invention. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings and embodiments. Preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0025] The reagents used in the following examples, unless otherwise specified, are all commercially available; the methods used in the following examples, unless otherwise specified, are all achievable by conventional methods.

[0026] Table 1 Raw material composition of modified epoxy resin in Examples 1-3

[0027]

[0028] Example 1 Preparation of modified epoxy resin:

[0029] According to the weight proportions, 26.4 parts of E20 resin, 6.6 parts of 638S epoxy resin and 20.6 parts of diethylene glycol monobutyl ether were stirred and dissolved uniformly at 130°C, and then mixed solution B was added dropwise over 20 minutes. Mixed solution B was prepared by mixing 2.1 parts of 85% phosphoric acid solution and 3.0 parts of ethylene glycol monobutyl ether. Then, stirring was maintained for 1 hour. The temperature was lowered to 60°C, 4.8 parts of diethanolamine were added, and stirring was performed for 20 minutes. Then, 36.5 parts of deionized water were added in 3 times, and stirring was performed uniformly for 30 minutes. The temperature was lowered to 50°C, filtered and packaged to obtain the modified epoxy resin.

[0030] The obtained sample has an appearance of a uniform liquid with opalescence and viscosity of 5500 mPa·s, a solid content of 40%, and a pH of 7.5.

[0031] Example 2 Preparation of modified epoxy resin:

[0032] According to the weight proportions, 24.3 parts of E12 resin, 9.3 parts of 638S epoxy resin and 21.2 parts of ethylene glycol monobutyl ether were stirred and dissolved uniformly at 130°C, and then mixed solution B was added dropwise over 20 minutes. The mixed solution B was prepared by mixing 1.3 parts of 85% phosphoric acid solution and 3.0 parts of ethylene glycol monobutyl ether. The mixture was stirred for 1 hour, cooled to 60°C, 2.4 parts of diethanolamine were added, and stirred for 20 minutes. Then, 38.5 parts of deionized water were added in 3 times, stirred uniformly for 30 minutes, and then cooled to 50°C, filtered and packaged to obtain the modified epoxy resin.

[0033] The samples obtained are Figure 3 As shown, the appearance is a uniform liquid with opalescence and viscosity of 11400 mPa·s, a solid content of 38%, and a pH of 8.5.

[0034] Example 3 Preparation of modified epoxy resin:

[0035] According to weight proportions, 8 parts of E20 resin, 18.2 parts of E06 resin, 7.5 parts of 638S epoxy resin and 24.0 parts of ethylene glycol monobutyl ether were stirred and dissolved uniformly at 130°C, and then mixed solution B was added dropwise over 20 minutes. The mixed solution B was prepared by mixing 1.3 parts of 85% phosphoric acid solution and 3.0 parts of ethylene glycol monobutyl ether. The mixture was stirred for 1 hour, cooled to 60°C, 3.0 parts of diethanolamine were added, and stirred for 20 minutes. Then, 35 parts of deionized water were added in 3 times, stirred uniformly for 30 minutes, and then cooled to 50°C, filtered and packaged to obtain the modified epoxy resin.

[0036] The obtained sample has an appearance of a uniform liquid with an opalescent consistency, a viscosity of 49000 mPa·s, a solid content of 38%, and a pH of 8.5.

[0037] Table 2 Raw material components of each water-based self-adhesive insulating varnish in Examples 4-6

[0038] materials Example 4 Example 5 Example 6 Modified epoxy resin 72 75 68 Waterborne polyurethane resin 5.5 8.0 3.4 Wetting agent Byk349 0.3 0.3 0.3 Deionized water 22.2 16.7 28.3 Total 100 100 100

[0039] Example 4

[0040] According to the weight ratio, 72 parts of the modified epoxy resin prepared in Example 1, 5.5 parts of the aromatic waterborne polyurethane resin with a deblocking temperature of 70-110°C, 0.3 parts of the wetting agent Byk349, and 22.2 parts of deionized water were stirred and mixed uniformly to obtain the water-based self-adhesive insulating paint. The product picture is as shown Figure 4 shown.

[0041] Example 5

[0042] According to weight proportions, 75 parts of the modified epoxy resin prepared in Example 2, 8.0 parts of an aromatic waterborne polyurethane resin with a deblocking temperature of 70-110° C., 0.3 parts of a wetting agent Byk349, and 16.7 parts of deionized water were stirred and mixed uniformly to obtain the waterborne self-adhesive insulating varnish.

[0043] Example 6

[0044] According to weight proportions, 68 parts of the modified epoxy resin prepared in Example 3, 3.4 parts of an aromatic waterborne polyurethane resin with a deblocking temperature of 70-110° C., 0.3 parts of a wetting agent Byk349, and 28.3 parts of deionized water were stirred and mixed uniformly to obtain the waterborne self-adhesive insulating varnish.

[0045] Application Examples

[0046] The water-based self-adhesive insulating varnish obtained in Example 4 was sprayed with a 4-head DV60 medium-speed enameling wire machine (reference Figure 1 ) was used to conduct coating experiments, using the same primer and wire of the same material, but with different diameters. Figure 2 This is a picture of the coated enameled wire.

[0047] Table 3 Application example coating process parameters and performance test indicators

[0048]

[0049]

[0050] It can be seen from Table 3 that when the line speed is 70-170 m / min, the curing temperature is 240-280°C, and the annealing temperature is 420-480°C, the coating performance obtained by coating the water-based self-adhesive insulating paint in the embodiment of the present invention can be better than the national standard requirements, especially when the line speed is 170 min, the curing temperature is 280°C, and the annealing temperature is 400°C, the coating performance is the best.

[0051] In summary, it can be seen that the polyurethane modified epoxy water-based water-based self-adhesive insulating paint for self-adhesive wire of the present invention adopts water-based resin instead of oily resin, and uses polyurethane resin to modify epoxy resin, which greatly improves the safety (the paint liquid is non-flammable and non-explosive) and environmental protection of the self-adhesive water-based self-adhesive insulating paint, and the coating curing temperature is reduced, which is 100 degrees lower than the oily curing temperature, and can be quickly cured at 280 degrees; the flexibility, adhesion and electrical properties of the obtained coating are also significantly improved, among which the self-adhesive adhesion at 150 degrees for 30 minutes is greater than 2.1N, which is nearly 7 times the national standard of oily.

[0052] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A polyurethane modified epoxy water-based self-adhesive insulating varnish for enameled wire, characterized in that: The water-based self-adhesive insulating varnish is prepared from the following raw materials in weight percentage: 60-80% modified epoxy resin, 3-8% water-based polyurethane resin, 0-1% wetting agent, and the balance deionized water; The modified epoxy resin is prepared by the following method: bisphenol A epoxy resin, novolac epoxy resin, and solvent A are mixed and dissolved at 130°C, then dropwise added to mixed solution B, mixed and reacted, then cooled to 60°C, added diethanolamine for mixed reaction, and finally added deionized water, dispersed evenly, cooled to 50°C and filtered; the solvent A is one or more of diethylene glycol monobutyl ether, isomers of diethylene glycol monobutyl ether, and ethylene glycol monobutyl ether; the mixed solution B is a mixture of phosphoric acid and ethylene glycol monobutyl ether; the novolac epoxy resin is 638s epoxy resin; The bisphenol A epoxy resin is one or more of E20, E12, and E06 epoxy resins; According to the mass ratio, bisphenol A epoxy resin: novolac epoxy resin: solvent A: mixed solution B: deionized water = 30~40: 6~10: 20~30: 4~5: 30~40; The waterborne polyurethane resin is a waterborne polyurethane resin with a deblocking temperature of 70-110°C.

2. The water-based self-adhesive insulating varnish according to claim 1, characterized in that: The wetting agent is BYK349.

3. The water-based self-adhesive insulating varnish according to claim 1, characterized in that: The waterborne polyurethane resin is an aromatic waterborne polyurethane resin.

4. The water-based self-adhesive insulating varnish according to claim 1, characterized in that: In the mixed solution B, phosphoric acid:ethylene glycol monobutyl ether=1:1-3.0, and the phosphoric acid is 85wt% phosphoric acid.

5. The water-based self-adhesive insulating varnish according to claim 1, characterized in that: The modified epoxy resin has a viscosity of 4000-60000 mpa·s, a solid content of 38-40%, and a pH of 7.0-9.

0.

6. The use of the water-based self-adhesive insulating varnish according to any one of claims 1 to 5, characterized in that: The water-based self-adhesive insulating varnish according to any one of claims 1 to 5 is coated on the surface of the wire through an enameling wire machine, the wire diameter is 0.04-0.80 mm, the production line speed is 70-300 m / min, the curing temperature is 200-280° C., and the annealing temperature is 420-480° C.

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