Chrome-free material for insulation coating of non grain-oriented electrical steel

FIELD: metallurgy.

SUBSTANCE: invention relates to chrome-free material for an insulation coating of non grain-oriented electrical steel. Material contains the following components with the corresponding weight fractions: primary acid salt of metal of phosphorus acid in the volume of 100 fractions, epoxy resin in the volume of 10-60 fractions, a drying agent - naphthenate or a drying agent - salt of metal of isooctane acid in the volume of 0.001-10 fractions, an organic solvent in the volume of 0.001-100 fractions and clean water in the volume of 60-2000 fractions. As primary acid salt of metal of phosphorus acid there used is Al(H2PO4)3, Mg(H2PO4)2, Ca(H2PO4)2, Zn(H2PO4)2. As epoxy resin there used is water-soluble epoxy resin or an epoxy resin emulsion.

EFFECT: after chrome-free material of an insulation coating is applied to non grain-oriented electrical steel, it has highly transparent appearance, excellent insulation properties, corrosion resistance, adhesion ability, weldability and processibility, which eliminates demerits inherent in existing chrome-free coatings, for example adhesiveness and bad wear resistance, as well as meets environmental protection requirements.

5 cl, 4 tbl

 

Field of the invention

The invention relates to the production of non-oriented electrical steel, in particular to a material for the insulating coating non-oriented electrical steel, containing chrome.

Prior art

Electrical steels are iron-silicon soft magnetic alloy with very low carbon content, which is mainly used in the manufacture of electric motors, generators, iron core transformers, etc. iron Loss of electrical steel are the main indicator used in the measurement properties of the products of electrical steel. The iron losses mainly consist of three parts: hysteresis losses, eddy current losses and anomalous losses. In the subsequent processes non-oriented electrical steel is usually subjected to punching to obtain a rod-like workpieces which are stacked and fastened by welding or riveting.

Typically, the surface of non-oriented electrical steel is necessary to apply an insulating coating to ensure a high interlayer strength. This strength can minimize the eddy current losses in the stator, the material which is obtained after stamping and stacked�I electrical steel sheets. Insulating coating steel is usually called textured coating. Textured coating must have good adhesion to prevent delamination of coating from the edges of electrical steel sheets during punching of the blanks. In forging, sleazemania and/or cutting steel should not be excessive spraying of insulation coating to prevent the accumulation of some of the sprayed material on the feed rollers or other devices, as this may cause deterioration forms for stamping or cutting of material. Also the insulation coating should be allowed to carry out welding iron cores with acceptable speed.

Insulating coating that is applied to the surface of non-oriented electrical steel can be divided into the following types: organic coating, inorganic coating and composite organic-inorganic coating, composite, organic-inorganic coating combines the advantages of both fully organic coatings with good penetration, and is completely inorganic film with good heat resistance and weldability, thereby satisfies the needs of most users and therefore is widely used.

Known material for the formation of isolatio�tion of the coating on the electrical steel sheet, which contains a film-forming component of the inorganic chromate and resin component, see US 4,844,753 C. the Resin component is a mixture of acrylic acid or emulsion of acrylic acid with a copolymer of styrene and melamine resin fraction 0.2-1 µm.

U.S. patent US 4,618,377 describes the composition of the organic-inorganic coatings for forming insulating coatings on the surface of electrical steel, which includes one kind of organic resin, one kind of resin particles, improved with the aid of dispersants, and one kind of solution containing not less than one kind of inorganic composite phosphate or chromate. Korean patent KR 25106, 31208, 31219, patents USA US 4316751, US 4498936 and the Japan patent JP 50-15013 describe a method of manufacturing chromostereopsis organic-inorganic coating. However, all formulas of these patents are the oxides of chromium or chromates. In connection with the Carcinogenicity of chromates their use is limited to become stricter and stricter, stricter requirements for the protection of the environment.

Because of the above reasons is the rapid development of creating formulas insulating coating for non-oriented electrical steel, chromium. In conventional chromium-free semi-organic coating, as a replacement IIR�Matam phosphates are introduced. Phosphate coating has good insulating properties and heat resistance, but has a high abrasion forms when stacked stamping blanks, as well as low corrosion resistance and low adhesion properties of the coating due to the lack of chromates. Thus, in U.S. patent US 2,743,203 describes the preparation of a good insulating film from a solution containing 7% to 50% of free phosphoric acid or from a phosphoric acid solution with dissolved magnesium oxide. U.S. patent US 4,496,399 describes inorganic-organic phosphate insulating coating. The inorganic part of the ingredients include magnesium phosphate and aluminum, colloidal silicon dioxide, and acid anhydride chromium, or a certain type of particles of aluminum silicate, and the organic portion is an emulsion of acrylic acid or ethylene acetate. The disadvantage of such coatings is that the inorganic part contains free phosphoric acid, which reacts with the steel surface at high temperature, and solidification of magnesium phosphate should be carried out at high temperature to prevent bonding of the workpieces with each other, the resin tends to decompose, making the brown coating. Furthermore, the use of an acid anhydride chromium is environmentally unfavorable.

In Pat�those of Japan JP 2004-322079 described a method for improving the corrosion resistance of the coating by use of a compound of phosphate with certain proportions of aluminum phosphate, magnesium phosphate and calcium phosphate. Through the use of phosphate in the coating of excess residual phosphoric acid easily causes the bonding of the workpieces. In Japan patent JP 11-131250 and Korean patent KR 1999-26912 described the use of a bonding agent silicon to prevent interlayer bonding caused by the residual phosphoric acid. Korean patent KR 1999-26912 and the Japan patent JP 3370235 describes the use of colloidal solution of silicon oxide, colloidal solution of alumina microparticles of zirconium, etc., to obtain an insulating coating non-oriented electrical steel with high corrosion resistance and good adhesive properties. These formulas containing phosphates and inorganic colloids as main substances still contain the problem of interlayer bonding due to the presence of phosphates, as well as the problem of low corrosion resistance due to the presence of colloidal silica.

In the case of chromium-free semi-organic coating, in which the basic substance is used, the phosphate, the residual phosphoric acid is extremely high, the probability of problems interlayer bonding. In European patent EP 1208166 B1 uses liquid insulation coating containing 100 parts of dihydrogenphosphate�and aluminum, 28-98 parts of the emulsion of acrylic acid with styrene, 6-18 parts of zinc nitrate, 4-13 parts silicon compounds, 18-35 g of glycol and 3-11 g of a nonionic surfactant, which has the potential for water absorption due to the lack of residual stabilizer phosphoric acid. In addition, using a zinc nitrate, and the presence of nitrate ions has on the corrosion resistance extremely negative impact. In U.S. patent US 5,955,201 as the stabilizer of residual phosphoric acid are inorganic particles of silicate that can effectively solve the problem of interlayer bonding. However, the inorganic silicate particles can't be dissolved in the solution, and therefore precipitate. In the absence of complete mixing to achieve the effect from them is difficult. In the international application WO 2008/016220 A1 said interlayer bonding can also be solved through the use of cobalt hydroxide and strontium hydroxide as a stabilizer of the residual phosphoric acid, however, the above stabilizers are inorganic particles that are difficult to efficiently mix.

Currently being manufactured and used in China coating without chromium contain less of inorganic ingredients. Although these coatings look good and have good penetrability, they feature�I low resistance, and so after high temperature treatment of the interlayer current resistance and insulating properties of the coatings are substantially reduced, the coating easily naglergasse, resulting in product characteristics deteriorate.

Non-oriented electrical steel sheet is divided into the so-called white and black steel, depending on the application of annealing for stress relieving. In the areas of application of non-oriented electrical steel, for example, in electric machines of medium and small size, as well as in the leaves for power tools, requires the use of annealing for stress relief, also requires reducing losses of iron electrical steel sheet and improve the electrical characteristics. Consumers in these areas typically have the following requirement: coating of sheets of textured electrical steel after performing annealing for stress relief should have a black color with a lustrous sheen. If the coating obtained after annealing Matt, it is believed that the annealing is carried out incorrectly, and coatings have poor insulating properties, which dramatically increases the likelihood that coverage will be rejected downstream users. All the above-mentioned coating not containing chromium, after annealing for stress relief mats become�mi, i.e. do not meet the demands of consumers.

Thus, it is particularly important to develop an environmentally friendly semi-organic insulation coating for cold-rolled non-oriented electrical steel to ensure such properties of non-oriented electrical sheet steel, good surface resistivity, low eddy current losses and good resistance to moisture absorption and good adhesion to the coating sprayed when cutting strips and stamping and did not spoil the shape; also the coating should not to form too many holes for ventilation in the welding process and should not react with various cooling agents and frozen engine oil used in the compressor; in addition, in the production and use of products coverage should not emit harmful substances such as hexavalent chromate.

The European Commission and the European Parliament issued two standard Directive of 13 February 2003, namely the Directive on waste electrical and electronic equipment (WEEE) and the Directive on restriction of hazardous substances (ROHS) in electrical and electronic equipment, according to which from 1 July 2006 index the content of harmful substances in e�krichesky and electronic products, sold on the European market must comply with the specified conditions. Among the limited harmful substances are: cadmium, lead, mercury, hexavalent chromate, polibromirovannyh diphenyl, polymerized diphenyl bromate and ether, etc.

Disclosure of the invention

Before the invention the task of creating material for the insulating coating non-oriented electrical steel, containing chrome. The coating uses as a naphthenate drier and salt isooctanol acid, which can effectively prevent the viscosity of the insulation coating not containing chromium. At the same time, due to the black coating provides the desired black color with a lustrous sheen that allows you to meet the demands of downstream users. Proposed in the present invention the coating is a new type insulating material for coating non-oriented electrical steel, containing chromium, with broad prospects for application.

For solving the above problems, the invention uses the following technical solutions.

The material for the insulating coating non-oriented electrical steel, containing chromium, contains the following components with the respective mass proportions: primary acidic metal salt of phosphoric �of islote - 100; epoxy - 10-60; drier naphthenate or metal salt isooctanol acid is 0.001-10; the organic solvent is 0.001-100; pure water 60-2000.

Primary acid metal salt of phosphoric acid can be obtained by mixing the hydroxides or oxides of the metal with phosphoric acid, a common chemical formula is M(H2PO4)n, where n is the ion valence of the metal M; in particular, as the primary metal salt of phosphoric acid can be used Al(H2PO4)3, Mg(H2PO4)2Ca(H2PO4)2, Zn(H2PO4)2etc., wherein the Al composition(H2PO4)3the mole ratio of Al2O3to H3PO4is 0.14 to 0.20:1; in the case of divalent metal phosphates, such as Mg(H2PO4)2Ca(H2PO4)2or Zn(H2PO4)2the molar ratio of MO (metal oxide) to H3PO4is of 0.40 to 0.60:1. Typically, when a decrease in the ratio of metal oxide and phosphoric acid is below the specified range in the solution remains too much phosphoric acid, resulting in adhesion of coating deteriorates, making it unfit for use; if the ratio exceeds the specified upper limit, the solution becomes unstable. These primary acidic metal salt of the phosphorus�Oh acids can be used individually or in combination with each other.

As the epoxy resin can be used, the epoxy resin emulsion or a solution of water-soluble epoxy resin, for example, emulsions of epoxy resin a, A, E20, manufactured and sold by the company Shanxi BOAO Chemicals Co. Ltd. (LLC "chancy BOAO chemicals Co. Ltd."), or water-soluble epoxy resin 681, 682, 811, manufactured and sold by the company Yingkou XINGHUO Chemicals Co. Ltd. LTD. ("Yingkou SHINHWA chemicals Co. Ltd.). Epoxy resin, which acts as the organic component in the coating solution, improves adhesion and viscosity of the insulation coating, and prevents the flaking of the coating from the substrate. Epoxy resins are divided into two types - soluble and insoluble in water. Epoxy resin, insoluble in water, may be introduced into the coating in the form of an emulsion, and water-soluble epoxy resin can be dissolved directly in water specific improved method, with such type epoxy resin can be used directly in a solution of chromium coating. If the content of substances of this kind in the formula of the coating is too small, the insulating coating becomes too granular, easily peels off and sprayed, resulting in no guarantee adhesion of the coating; if the content is too high, worsening garoto�bone and weldability of insulation coating. The epoxy resin emulsion is added in an amount of 10-60 mass parts, preferably 8 to 60 mass fraction (where the share of primary acidic metal salt of phosphoric acid is 100 mass fraction).

The above-mentioned desiccant is introduced into the coating in the form of supplements. In the German standard DIN 55901 desiccant is defined as follows: "the dryer is an organic compound of the metal, the solids are in solution, which dissolves in organic solvents and resins". In chemical composition it belongs to the category of metal melts (e.g., metal salt of higher aliphatic acid) and reduces the drying time, speeding up the grappling, when added to unsaturated oils and resins. Dehumidifiers are generally divided into the following categories: 1) primary dehumidifiers, which, in General, represent a metal melt containing oxides with multiple valence States, and is capable of causing an oxidation reaction-recovery; dehumidifiers in this category are common in this industry include melts of metals such as cobalt, manganese, vanadium and cerium; 2) secondary dehumidifiers that represent melts of metals with one valence state oxide, for example, melts of metals such as calcium, potassium, barium and zinc, and drying themselves have no effect, purchasing dewatering properties t�only when used in conjunction with primary driers; 3) binder desiccant, for example a melt of zirconium, in which the mechanism of catalysis of the reaction process is based on the reaction between metals and hydroxyl or carboxyl groups of the resins.

In the present invention as desiccants can be used conventional naphthenate metals such as cobalt naphthenate, manganese, iron, copper, cerium, zinc, calcium, potassium, barium or Nickel; or can be used metal salt isooctanol acid, such as potassium, manganese, sodium, Nickel, copper, cerium, zinc, zirconium or calcium. These types of substances can be used individually or in combination in chromium liquid coating for the purpose of catalysis reaction of cross-linking resins to accelerate the formation of the film, and simultaneously improve the strength and durability of the coating. Dehumidifiers are added in the amount of 0.001-10 mass fraction (where the share of primary acidic metal salt of phosphoric acid is 100 mass fraction).

As the organic solvents can be used glycol or glycerin. Substances of this type are mutually soluble in water and can dissolve in it such dryers as the naphthenate salt and isooctanol acid, which reduces the surface tension of the solution and to prevent such defects in the coating film, laces, etc. Organic solvents �dobavlyautsya in the amount of 0.001-100 mass fraction (where the share of primary acidic metal salt of phosphoric acid is 100 ppm). Preferably, the desiccant-naphthenate or dehydrator-metal salt isooctanol acid to use in the amount of 5-8 lobes.

Water is used as the main solvent and regulates the ratio of components in the proposed coating material that facilitates the process of its application. Water is added in the amount of 60-2000 mass fraction (where the share of primary acidic metal salt of phosphoric acid is 100 mass fraction).

The above five components are mixed in the specified proportions to form a homogeneous solution, i.e. chromium solution of the liquid coating. The mixed solution can be directly used in various systems of machines for coating.

Characteristics the thickness of the sheets non-oriented electrical steel may be different, for example, 0.20 mm, 0.35 mm, 0.50 mm, 0.65 mm, etc., After the cold rolling process of the above sheets non-oriented electrical steel is required to perform annealing after cleaning the surface, and then conduct a post-treatment, after which the sheets are fed in a roller device for applying a chromium coating. The roller device may be of the sliding or technolology, there is also no restriction on the presence or absence of slits in the rollers. The temperature of the steel strip in the CoE�tion curing under the influence of fire is in the range of 200-350°C. If the temperature is too low, the chemical reaction of the coating material will be incomplete, the coating will be sticky and not strong enough; if the temperature is too high, the decomposition of the epoxy resin and the coating will burn out and turn yellow.

The positive effects.

Proposed in the present invention is chromium-free insulating material of the coating after application on non-oriented electrical steel has a highly transparent appearance, excellent insulation properties, corrosion resistance, adhesion, weldability and machinability, which eliminates the disadvantages inherent in existing chromium coatings, such as stickiness and poor wear resistance, and also meets the requirements for the protection of the environment.

Proposed in the present invention is chromium-free insulating material coating can be used for high-quality and highly efficient products non-oriented electrical steel, and products for medium and low quality. The liquid coating material may be applied to a substrate of cold-rolled electrical steel using a roller device, and then subjected to heat treatment to form the film. Thus, the invention can be widely used p�izvoditelyami non-oriented electrical steel within the country and abroad.

Best mode of carrying out the invention

The invention is further described in detail with reference to specific options for implementation; however, the scope of legal protection of this invention is not limited to the implementation.

Options for implementation 1-6

1) In the formula contains (in mass shares): dihydrogenphosphate aluminum naphthenate drier, water-soluble epoxy resin, glycol and pure water, see Table 1.

2) Preparation and application: mix the above components at room temperature, then the mixture was stirred using a stirrer at low speed until a homogeneous solution; the solution is applied to the surface of sheets of textured electrical steel with thickness of 0.5 mm using a roller device at a speed of deposition of 1.8 g/m2is then subjected to heat treatment for the production of films using flame heating furnace at a sheet temperature of 200-500°C. operating characteristics of the coatings are given in Table 2.

5
Table 1
Formula of the material for the insulating coating
No.Formula
D�hydrogenphosphate aluminum Water-soluble epoxy resinGlycolNaphthenate drierClean water
Option 1100681,3010cobalt naphthenate, 880
Option 2100682,4050the calcium naphthenate, 260
Option 3100811,5030zinc naphthenate, 10500
Option 4100811,205the manganese naphthenate, 11000
Option 5100681,100.001cobalt naphthenate, 0,001300
Option 6100682,15the iron naphthenate, 7700
Comparative object 1chromostereopsis insulating coating, the formula: chromate + emulsion copolymer cinepazide + boric acid + glycerol

Table 2
Performance coatings
No.Adhesion, diameter 20 cmBullies when stampout 50 µmWeldability, cm/minAesthetic propertiesCorrosion resistanceInterlayer strength, Ω.cm2on the sheet
Option 1Small flaking>1.5 million times≤40Shiny surface15%30
Option 2Exfoliation no>1.7 million times≤30Gloss over�spine 25%45
Option 3Exfoliation no>1.6 million times≤50Shiny surface15%25
Option 4Exfoliation no>1.7 million times≤40Shiny surface10%48
Option 5Exfoliation no>1.8 million times≤60Shiny surface20%36
Option 6Exfoliation no>1.6 million times≤50Shiny surface10%42
Comparative object 1Small flaking>1.4 million times≤10Brilliant �poverhnosti 40%15

The test conditions the characteristics listed below (further conditions are similar):

check adhesion: GB 2522-88 (national standard of China);

check stamping: number of stampings with the height of the Heckler >50 µm;

- inspection of welding: arc welding with tungsten electrode in inert gas (TIG), the amount of current is 120 A, the electrode material tonirovany Th tungsten-W, a flow rate of argon gas of 6 l/min, pressure 50 kg/cm2;

- validation of corrosion resistance: JIS Z2371;

check interlayer strength: JIS S.

As can be seen from Table 2, the coating is obtained from a chromium material for insulation coating proposed in the present invention, are very good.

Implementation options 7-13

1) In the formula contains (in mass shares): dihydrogenphosphate (aluminum, magnesium, calcium or zinc), emulsion of epoxy resin by weight in the dry state), drier metal salt isooctanol acid, glycerin and pure water, see Table 3.

2) Preparation and application: mix the above components at room temperature, then the mixture was stirred for 10 minutes using a magnetic stirrer; the resulting mixture is applied on the surface of sheets of textured electrical�otehnicheskogo steel of 0.5 mm thickness using a roller device at a speed of deposition of 1.8 g/m 2is then subjected to heat treatment for the production of films using flame heating furnace at a sheet temperature of 200-500°C. operating characteristics of the coatings are given in Table 4.

Table 3
Formula of the material for the insulating coating
No.Formula
DihydrogenphosphateThe epoxy resin emulsionGlycerinDrier metal salt isooctanol acidClean water
Option 7Dihydrogenphosphate magnesium, 100E, 100.01isooctanol manganese, 1700
Option 8Dihydrogenphosphate calcium, 100E, 35100isooctanol cobalt, and 0.5900
Option 9Dihydrogenphosphate aluminum, 100 E20, 1580isooctanol calcium, 51500
Option 10Dihydrogenphosphate zinc, 100E, 6050isooctanol cerium, 21900
Option 11dihydrogenphosphate magnesium, 100E, 5040isooctanol cobalt, 8300
Option 12Dihydrogenphosphate zinc, 100E20, 4510isooctanol zinc, 10400
Option 13Dihydrogenphosphate aluminum, 100E, 302isooctanol cerium, 5200
Comparative object 2chromostereopsis insulating coating, the formula: chromate + emulsion copolymer cinepazide (cinepazid) + boric acid + glycerol

Table 4
Performance coatings
No.Adhesion, diameter 20 cmBullies when Stampace, 50 µmWeldability, cm/minAesthetic propertiesCorrosion resistanceInterlayer strength, Ω.cm2on the sheet
Option 7Exfoliation no>2,0 million times≤55Smooth surfaceNo15
Option 8Exfoliation no>2,0 million times≤40Smooth surfaceNo34
Option 9Exfoliation no>2,0 million times≤30Smooth surfaceNo28
Option 10Exfoliation no>2,0 million times≤45Smooth surfaceNo50
Option 11Exfoliation no>2,0 million times≤50Smooth surfaceNo80
Option 12Exfoliation no>2,0 million times≤40Smooth surfaceNo40
Option 13Exfoliation no>2,0 million times≤30Smooth surfaceNo30
Comparative object 2Small flaking>1.7 million times≤10Smooth surfacegood

�de:

test for dissolution of phosphorus: put samples of fixed area coated in boiling water, boiled for 10 min, then measure dissolved in boiling water phosphorus using ICP (mass spectrometry with inductively coupled plasma) to produce results makes conversion; aesthetic properties: the stickiness of the surfaces was determined by touch of hands.

As seen from Table 4, the coating not containing chromium, of embodiments 7-13 have a very high performance, and the rate of dissolution (separation) of phosphorus lower that solves the problem of stickiness coatings.

Of embodiments 1-13 shows that the implementation of the present invention allows to obtain an insulation coating for non-oriented electrical steel, containing chromium, with excellent features that can replace existing chromostereopsis coverage. Proposed in the invention coating fully meet the EU requirements for the protection of the environment during the production of electrical steel.

1. The material for the insulating coating non-oriented electrical steel, chromium-free and contains the following components with the respective mass proportions:

100
epoxy10-60
naphthenate drier
or metal salt isooctanol acidOf 0.001-10
organic solventOf 0.001-100
clean water60-2000,

the epoxy resin used is a water-soluble epoxy resin or emulsion of epoxy resin, as a desiccant-naphthenate used cobalt naphthenate, manganese, iron, copper, cerium, zinc, calcium, potassium, barium or Nickel, as the drier is a metal salt isooctanol acid salt is used isooctanol acid metal such as potassium, manganese, sodium, Nickel, copper, cerium, zinc, zirconium or calcium, and the organic solvent is a glycol or glycerin.

2. Material according to claim 1, characterized in that as the primary acidic metal salt of phosphoric acid is used Al(H2PO4)3, Mg(H2PO4)2, Sa(H2PO4)2or Zn(H2PO4)2.

3. Material according to claim 2, characterized in that in with�the composition Al(H 2PO4)3the mole ratio of Al2O3to H3PO4is 0.14 to 0.20:1.

4. Material according to claim 2, characterized in that the composition Mg(H2PO4)2, Sa(H2PO4)2or Zn(H2PO4)2the mole ratio of MgO, Cao, ZnO by H3PO4is 0,40-0,60:1.

5. Material according to claim 1, characterized in that the desiccant-naphthenate or dehydrator-metal salt isooctanol acid in a preferred embodiment is used in the amount of 5-8 lobes.



 

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FIELD: polymer materials.

SUBSTANCE: insulating varnish for coating enameled wires contains polyester resin, titanium catalyst, and organic solvents, titanium catalyst being, in particular, tetrabutoxytitanium and organic solvents being petroleum solvent and cresol solvent recovered by treatment coal oil and consisting of phenol, o-, m-, and p-cresols, and xylenols, which has following fraction composition (by volume): up to 180°C not more than 3%, 190-205°C at least 70% and up to 210°C at least 85%.

EFFECT: lowered cost price of varnish and improved quality of finished product.

1 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: there is disclosed insulating coating composition, containing bitumen in amount 90-100 wt fractions, fluorocarbon polymer 32 LN in amount 10-15 wt fractions, butyl acetate in amount 40-45 wt fractions, acetone in amount 40-45 wt fractions and mica in amount 2-3 wt fractions.

EFFECT: improved insulating properties, mechanical strength and chemical stability.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: varnish contains a varnish base, a functional additive which increases coating hardness, siccative HF and methyl ethyl ketoxime radical polymerisation inhibitor. The varnish base is an oligomer with strongly polar chromane rings. The oligomer is obtained by reacting tung oil and 101L phenol-formaldehyde resin, taken in equivalent ratio of 1:0.15-0.18, respectively, while heating said mixture for 60 minutes at temperature 160°C. After extracting water, temperature is raised to 182°C until achieving viscosity of 25-36 s. The oligomer is added to the composition in 50% xylene solution. The functional additive used is rosin ester with glycerine. Components are in the following ratio, wt %: oligomer - 31.0-36.2, rosin ester with glycerine - 9.0-3.8, siccative HF - 2.00, methyl ethyl ketoxime - 0.60, xylene - the balance.

EFFECT: wider raw material base, replacing molten amber, which is not produced on an industrial scale, with rosin ester with glycerine, high content of non-volatile substances, elasticity and electrical strength of the coating.

1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to use of nanomaterials in wire enamel for improving thermal properties of enamel. The nanomodified wire enamels are usually used in making insulated winding wire. The polymer base of wire enamel is selected from a group comprising polyamideimide, polyester, polyesterimide, polyurethane and mixtures thereof. The nanomaterial is selected from a group comprising nano-oxides, metal nano-oxides, metal oxides or hydroxides of aluminium, tin, born, germanium, gallium, lead, transition metals, lanthanides, actinides and mixtures thereof. The nanomaterial is also selected from a group comprising nano-oxides, metal nano-oxides, metal oxides and hydroxides of aluminium, silicon, titanium, zinc, yttrium, vanadium, zirconium, nickel and mixtures thereof. After applying enamel on the wire and curing thereof, the wire exhibits improved thermal and mechanical properties.

EFFECT: improved thermal properties of enamel.

8 cl, 6 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in producing wires with enamel insulation for motors, coils and transformers. The wire enamel contains binder, an organic solvent, auxiliary substances and additives, an adhesion promoter selected from imidazole, pyrrolidone, amidocarboxylic acids, derivatives thereof and mixtures thereof. The method of coating electric wires with the enamel involves providing an electric wire, applying the enamel and curing.

EFFECT: improved adhesion of the enamel to electric wires.

20 cl, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to production of electrically insulating lacquer for coating metal bases. Said lacquer contains (wt %): epoxy-diane resin 7-7.4, polyphenyltetraepoxy siloxane - 2.4-3, alkyd-epoxy resin VEP-0179 - 2.4-3.8, triethylamine - 0.16-0.28, acetone - 20.1-23.6, distilled water - the balance. To apply the lacquer onto a metal substrate, two electrodes - the article-electrode and an auxiliary electrode - are immersed in said lacquer. Positive potential is applied across the article-electrode relative the second auxiliary electrode and with current density of 0.2-1.5 mA/cm2 for 5-15 s, a dense homogeneous electrophoretic film-forming precipitate is electrically deposited on the article-electrode. The article is then placed in a heating cabinet for 30-50 s in which there is a vacuum of 50-60 torr and temperature of 30-40°C. The article is then held in a furnace for 1-1.5 min at temperature of 400-500°C.

EFFECT: inventions reduce emissions of harmful volatile substances, increase mechanical strength and breakdown voltage of the electrical insulation, enable to deposit a dense, homogeneous and quality film layer without using any mechanical devices.

2 cl, 1 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to obtaining electroinsulating varnishes for covering metal bases, for instance, copper wires, starter slots and electric motor armatures, conductors of printed circuit boards, etc. Method of application of electroinsulating coating on metal substrate includes preparation of electrophoretic composition based on varnish PE-939 of grade B, for which purpose it is mixed with 1% ammonia solution, ethylcellosolve and dioxane, after which into prepared electrophoretic solution submerged are two electrodes at distance 10-30 mm, one of which is electrode-product and the other is auxiliary electrode; positive potential relative to second auxiliary electrode is supplied to said electrode-product, and dense homogeneous electrophoretic sediment of film-forming is electrically precipitated on product at current density 2-10 mA/cm2 for 10-20 s, after that, electrode-product is removed from varnish, placed into heat chamber, 50-60 Torr vacuum and temperature 30-40°C are created in heat chamber, and electrode-product is kept at said temperature for 20-40 s, after that said electrode-product is removed from heat chamber and placed into oven, inside which temperature 350-450°C is created, and electrode-product is kept in oven for 60-90 s, after which electrode-product is removed from oven.

EFFECT: method provides increase of quality and exploitation reliability of insulating coating: specific volume resistance, resistance to chemical reagents, elasticity, electric and mechanical strength.

FIELD: metallurgy.

SUBSTANCE: invention relates to chrome-free material for an insulation coating of non grain-oriented electrical steel. Material contains the following components with the corresponding weight fractions: primary acid salt of metal of phosphorus acid in the volume of 100 fractions, epoxy resin in the volume of 10-60 fractions, a drying agent - naphthenate or a drying agent - salt of metal of isooctane acid in the volume of 0.001-10 fractions, an organic solvent in the volume of 0.001-100 fractions and clean water in the volume of 60-2000 fractions. As primary acid salt of metal of phosphorus acid there used is Al(H2PO4)3, Mg(H2PO4)2, Ca(H2PO4)2, Zn(H2PO4)2. As epoxy resin there used is water-soluble epoxy resin or an epoxy resin emulsion.

EFFECT: after chrome-free material of an insulation coating is applied to non grain-oriented electrical steel, it has highly transparent appearance, excellent insulation properties, corrosion resistance, adhesion ability, weldability and processibility, which eliminates demerits inherent in existing chrome-free coatings, for example adhesiveness and bad wear resistance, as well as meets environmental protection requirements.

5 cl, 4 tbl

FIELD: electricity.

SUBSTANCE: invention relates to electric engineering, and more specifically to compositions of insulating coatings and impregnation compounds for windings of electrical machines and mechanisms operated at high temperatures and intended mainly for application of coating by dipping. Impregnating insulating enamel includes polymethylphenylsiloxane lacquer, metal oxides, acrylate copolymer, butyl acetate, silicone antifoamer, rheological additive with thixotropic effect and aromatic solvent.

EFFECT: coatings are obtained with electric strength of enamel film at AC voltage (50 Hz) at temperature of 15-35°C and relative humidity of 45-75% equal to at least 60 kV/mm and specific volume resistance of enamel film in initial state at temperature of 15-35°C relative humidity of 45-75% equal to at least 1,0·1012 Ohm·cm.

1 tbl

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