Non-oriented silicon steel, coating liquid and preparation method thereof, iron core and preparation method thereof

Abstract

The present application relates to non-oriented silicon steel and its coating liquid and preparation method, iron core and its preparation method, and belongs to the technical field of non-oriented silicon steel coating; the components of the coating liquid include water-based resin, inorganic salt, auxiliary agent and solvent, and the water-based resin includes acrylic resin and epoxy resin. In the drying process of preparing silicon steel, the inorganic salt can serve as a skeleton to play a supporting effect, and at the same time, the thermosetting resin in the water-based resin reacts chemically at high temperature, and the hardness of the cured resin is relatively high, which can synergistically increase the strength of the coating with the inorganic salt, so that the silicon steel can contact the furnace roller at high temperature. In addition, the thermoplastic resin in the water-based resin loses water and solvent and is densely accumulated into a film, so that when the coating sheets are heated and compressed after being processed into the iron core, the chain groups of the water-based resin macromolecules stretch and diffuse each other, and when it is cooled, some of the water-based resin macromolecules are linked to each other, and after the silicon steel forms the iron core, it can form a bonding force between the sheets of the iron core.

Description

Technical Field

[0001] The present application relates to the technical field of non-oriented silicon steel coating preparation, and provides non-oriented silicon steel and its coating liquid and preparation method, iron core and its preparation method. Background Art

[0002] With the development of the times, energy is becoming increasingly scarce. Reducing carbon emissions and reducing electricity consumption have become major issues facing the world today. Non-oriented silicon steel is widely used as the raw material for motor cores, playing an important role in the global wave of energy conservation, environmental protection, and low-carbon emission reduction. Studies have shown that the eddy current loss of high-grade non-oriented silicon steel accounts for more than 30% of the iron loss. Therefore, reducing eddy current loss is an important way to reduce iron loss. In order to reduce eddy current loss, it is necessary to apply a layer of insulating coating that can generate high impedance on the surface of silicon steel.

[0003] At present, when non-oriented silicon steel sheets are processed into iron cores, the silicon steel sheets are mainly fixed together by riveting and welding. The stator and rotor iron cores usually produced have poor tightness and there are gaps between the sheets, resulting in poor core stiffness. This causes large vibrations when the core rotates at high speeds, especially in the field of thin specifications, the core stiffness problem is more prominent.

[0004] The bonding force between non-oriented coatings can effectively improve the rigidity of the core. After the conventional ordinary coatings of non-oriented silicon steel are stacked into the core, no bonding force will be generated between the layers; generally, bonding force can be generated by coating the surface of the steel strip with a self-adhesive coating. The bonding strength of the self-adhesive coating is greater than 10Mpa, which is relatively high. In the production process of the self-adhesive coating, the steel strip needs to be baked at a temperature of 180-250℃ for 50-70S. Since the surface of the self-adhesive coating is sticky when it is greater than 70℃, a floater is used in the production process to prevent the strip from contacting the furnace roller. The production process has high requirements for equipment. After the self-adhesive coating is used to make the core, it needs to be heated and cured again when the customer uses it. Generally, it needs to be cured continuously for 0.4 hours to 4 hours at a curing pressure of 6-11bar and a curing temperature of 130℃ to 220℃. The heating time is long and the production efficiency is low. Therefore, the self-adhesive coating non-oriented silicon steel needs to adopt a special production process, which is complex in equipment, low in efficiency, high in cost, and narrow in application. Summary of the invention

[0005] The embodiments of the present application provide non-oriented silicon steel, its coating liquid and preparation method, iron core and preparation method thereof. After the silicon steel coated with the coating liquid is heated, the coating surface can generate a certain adhesion force, which can solve the technical problem of poor rigidity of the iron core made of existing non-oriented silicon steel insulating coating to a certain extent.

[0006] In a first aspect, an embodiment of the present application provides a non-oriented silicon steel coating liquid, wherein components of the coating liquid include an aqueous resin and an inorganic salt, and the aqueous resin includes an acrylic resin and an epoxy resin.

[0007] As an optional embodiment, the coating liquid further comprises an auxiliary agent, which can be selected from a film-forming auxiliary agent, a wetting agent and a defoaming agent.

[0008] As an optional implementation, the water-based resin includes at least one of an acrylic resin and an epoxy resin.

[0009] Optionally, the acrylic resin is selected from all-acrylic water-based resin, styrene-acrylic water-based resin, silicone-acrylic water-based resin, acetic acid-acrylic water-based resin, fluoroacrylic water-based resin, etc.; the epoxy resin is selected from modified copolymers or mixtures of glycidyl esters.

[0010] As an optional implementation, the inorganic salt is phosphate.

[0011] Optionally, the phosphate may be dihydrogen phosphate, and illustratively, the dihydrogen phosphate may be at least one of dihydrogen aluminum phosphate, dihydrogen zinc phosphate, dihydrogen magnesium phosphate, strontium phosphate, cobalt phosphate and nickel phosphate.

[0012] As an optional implementation, the mass proportion of the water-based resin is 20%-60%; and / or the solid content is controlled at 20-50%, and the viscosity is controlled at 9-20S.

[0013] Optionally, the mass percentages of the components of the coating liquid are: 40% to 60% of phosphate, 30% to 55% of water-based resin, and the rest are additives and deionized water.

[0014] In a second aspect, an embodiment of the present application provides a method for preparing the non-oriented silicon steel coating liquid according to the first aspect, the preparation method comprising:

[0015] mixing the phosphate solution and the water-based resin to obtain a mixed solution;

[0016] Add the auxiliary agent into the mixed solution and stir until the mixture is completely mixed to obtain a coating solution.

[0017] In a third aspect, an embodiment of the present application provides a non-oriented silicon steel, comprising a substrate and a coating attached to at least a portion of the surface of the substrate, wherein the coating is made from the non-oriented coating liquid described in the first aspect.

[0018] As an optional implementation, the coating has a thickness of 0.5-2 μm.

[0019] In a fourth aspect, an embodiment of the present application provides a method for preparing non-oriented silicon steel, the preparation method comprising:

[0020] Obtaining the coating liquid provided by the first aspect;

[0021] Applying the coating liquid to the surface of the substrate, and then baking to obtain a non-oriented silicon steel sheet;

[0022] Before the coating liquid is applied to the substrate, the substrate temperature is controlled to be below 50°C. Generally speaking, the substrate is a steel strip. In actual operation, the plate temperature of the annealed steel strip is controlled to be below 50°C.

[0023] The coating is carried out by a coating machine using a 2-roller or 3-roller reverse coating method;

[0024] As an optional implementation, baking is performed at a temperature of 300-650° C. for 20-40 seconds; the coating thickness is 0.5-2 μm.

[0025] In a fifth aspect, an embodiment of the present application provides a method for preparing an iron core, the method comprising:

[0026] After punching, the silicon steel sheets are stacked into an iron core, which is heated at 200℃~300℃ for 30 minutes under a curing pressure of 2~11bar. The heating method can be induction electromagnetic or resistance furnace. Induction electromagnetic heating is preferred, which has faster heating speed and shorter heating time;

[0027] The heated core can be forced to cool by air for 1-2 hours, or cooled naturally;

[0028] After heating and pressurizing, the silicon steel sheets will generate bonding force.

[0029] In a sixth aspect, the present application provides an iron core, which is manufactured using the method for manufacturing the iron core described in the fifth aspect.

[0030] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0031] The coating liquid provided in the embodiment of the present application adopts water-based resin including thermoplastic resin and thermosetting resin and inorganic salt as raw materials. In the drying process of preparing silicon steel, the inorganic salt can serve as a skeleton to play a supporting effect. At the same time, the thermosetting resin in the water-based resin undergoes a chemical reaction at high temperature. The cured resin has a high hardness and can synergistically increase the strength of the coating with the inorganic salt, so that the silicon steel can contact the furnace roller at high temperature. In addition, the thermoplastic resin in the water-based resin loses water and solvent and is densely accumulated into a film. When the coating sheets are heated and compressed after being processed into an iron core, the chain groups of the water-based resin macromolecules stretch and diffuse with each other. When it is cooled, some of the water-based resin macromolecules are linked with each other. After the silicon steel forms an iron core, the thermoplastic resin in the water-based resin forms a bonding force between the sheets of the iron core. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 A flow chart of a method for preparing non-oriented silicon steel provided in an embodiment of the present application;

[0035] Figure 2 A flow chart of a method for preparing an iron core provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0038] Non-oriented silicon steel is widely used as the raw material of motor cores, playing an important role in the global wave of energy conservation, environmental protection, and low-carbon emission reduction. Studies have shown that the eddy current loss of high-grade non-oriented silicon steel accounts for more than 30% of the iron loss. Therefore, reducing eddy current loss is an important way to reduce iron loss. In order to reduce eddy current loss, it is necessary to apply a layer of insulating coating that can generate high impedance on the surface of silicon steel.

[0039] At present, when non-oriented silicon steel sheets are processed into iron cores, the silicon steel sheets are mainly fixed together by riveting and welding. The stator and rotor iron cores usually produced have poor tightness and there are gaps between the sheets, resulting in poor core stiffness. Especially in the field of thin specifications, the core stiffness problem is more prominent.

[0040] The bonding force between the non-oriented coatings can effectively improve the core rigidity. Adhesion can be generated by using a self-adhesive coating on the surface of the steel strip.

[0041] The applicant intends to use a new coating. When the customer uses silicon steel sheets containing the adhesive coating to make iron cores, the adhesive force generated on the surface of the coating after the iron core is heated and pressurized can also effectively improve the stiffness of the iron core.

[0042] The embodiment of the present application provides a non-oriented silicon steel coating liquid and a product thereof, wherein the coating liquid comprises an aqueous resin and an inorganic salt, and the aqueous resin comprises a thermoplastic resin and a thermosetting resin.

[0043] In some embodiments, the water-based resin is an organic resin, including acrylic and epoxy resin, and the acrylic resin is selected from all-acrylic water-based resin, styrene-acrylic water-based resin, silicone-acrylic water-based resin, acetic acid-acrylic water-based resin, fluoroacrylic water-based resin, etc. The epoxy resin is selected from a modified copolymer or mixture of glycidyl esters, for example, including at least one of epoxy resins; the inorganic salt includes an inorganic phosphate, and illustratively, the inorganic phosphate can be specifically selected from at least one of aluminum dihydrogen phosphate, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, manganese dihydrogen phosphate, nickel dihydrogen phosphate, and cobalt dihydrogen phosphate.

[0044] In some embodiments, the mass proportion of the water-based resin is 20%-60%; the solid content of the water-based resin is 20%-50%; and the viscosity of the water-based resin is 9-20S.

[0045] The mass proportion of water-based resin is controlled at 20%-60%. If the amount of resin is too high, the hardness of the coating will be reduced and the steel plate will be easily scratched during processing. If it is too small, the hardness of the coating will be too high, the stamping performance of the coating will be reduced, and the punch press will be easily worn.

[0046] The solid content of the water-based resin is controlled at 20%-50%. If the solid content is too large, it will be difficult to stir the coating liquid raw materials evenly and the coating liquid will have poor stability. On the contrary, if the solid content is too small, the solvent content in the coating liquid will increase, which is not conducive to the drying process of the coating.

[0047] The viscosity of the water-based resin is controlled to be 9-20S. At this viscosity, the leveling and uniformity of the coating liquid are taken into consideration. If the viscosity is too large, streaks are likely to appear on the surface of the coating liquid. If it is too small, the coating thickness requirement cannot be met.

[0048] In some embodiments, the adhesive coating liquid further comprises additives, including film-forming additives, wetting agents, defoaming agents, etc. Optionally, the mass percentages of the components of the coating liquid are: 40% to 60% phosphate, 30% to 55% water-based resin, and the rest are additives and deionized water.

[0049] The preparation method of the coating liquid is as follows: obtaining a phosphate solution; mixing the phosphate solution and an aqueous resin to obtain a mixed solution; adding an auxiliary agent to the mixed solution and stirring until the mixture is completely mixed to obtain a coating liquid.

[0050] The above design uses water-based resins including thermoplastic resins and thermosetting resins and inorganic salts as raw materials. In the drying process of preparing silicon steel, the inorganic salt can serve as a skeleton to play a supporting role. At the same time, the thermosetting resin in the water-based resin undergoes a chemical reaction at high temperature. The cured resin has a high hardness and can synergistically increase the strength of the coating with the inorganic salt. Silicon steel can be in contact with furnace rollers at high temperatures, avoiding the problem of having to use a floater during the coating preparation process. In addition, the thermoplastic resin in the water-based resin loses water and solvent and is densely accumulated into a film, so that when the coating sheets are heated and compressed after being processed into an iron core, the resin chain groups stretch, and when they are cooled, the groups are linked to each other to form a bonding force between the sheets of the iron core.

[0051] Based on a general inventive concept, an embodiment of the present application further provides a non-oriented silicon steel, the steel comprising a substrate and a coating attached to at least a portion of the surface of the substrate, the coating comprising the coating provided above.

[0052] Since the substrate is coated with the above-mentioned coating, when the silicon steel is used to prepare the iron core, the adhesion force generated on the surface of the coating after heating and pressurization can also effectively improve the rigidity of the iron core; in combination with the use of electromagnetic induction heating and other methods, the heating time can be shortened and the processing efficiency can be greatly improved.

[0053] In some embodiments, the coating has a thickness of 0.5-2 μm.

[0054] The thickness of the coating is controlled to be 0.5-2μm. If the thickness is too large, the lamination factor will be reduced, affecting the magnetic properties of the product. If the thickness is too small, the coating resistance will be low.

[0055] like Figure 1 As shown, based on a general inventive concept, the embodiment of the present application further provides a method for preparing non-oriented silicon steel, the method comprising:

[0056] S1. Obtain the coating solution as provided above;

[0057] S2. Apply the coating slurry to the surface of the substrate, and then bake it to obtain steel.

[0058] In some embodiments, the baking temperature is 300-650° C.; the baking time is 20-40 seconds.

[0059] The baking temperature is controlled at 300-650℃ and the time is 20-40s. If the baking temperature is too high or the time is too long, the surface color of the coating will be affected; if the baking temperature is too low or the time is too short, the corrosion resistance of the coating will decrease.

[0060] The coating is carried out by a coater using a 2-roller or 3-roller reverse coating method.

[0061] like Figure 2 As shown, based on a general inventive concept, an embodiment of the present application further provides a method for preparing an iron core, the method comprising:

[0062] S1. The above-mentioned non-oriented silicon steel is stamped and stacked to obtain a semi-finished product;

[0063] S2. heating the semi-finished product to solidify the coating on the surface of the steel to obtain an iron core.

[0064] In some embodiments, the heating environment pressure is 5-11 bar; the heating temperature is 200-300° C.; and the heating time is 20-40 min.

[0065] The heating method can be induction or resistance furnace.

[0066] Based on a general inventive concept, an embodiment of the present application further provides an iron core, which is manufactured using the iron core manufacturing method provided above.

[0067] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0068] Example 1

[0069] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin, inorganic phosphate and auxiliary agent. The mass percentages of the water-based resin component in the entire coating liquid are as follows: acrylic resin 5.1%, polyester resin 2.9%, epoxy resin 3.2%, ethylene glycol 1%, glycerol 0.8%, silicone resin 1%, fluorine resin 1%, sodium allyloxyhydroxypropyl sulfonate 2%, OP-10 1%, sodium dodecylbenzene sulfonate 0.9%, sodium persulfate 1%, potassium bisulfite 0.1%; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: aluminum dihydrogen phosphate 22.1%, phosphoric acid 5.3%, magnesium dihydrogen phosphate 5%, calcium dihydrogen phosphate 2.9%, zinc dihydrogen phosphate 4%, strontium phosphate 2.7%, cobalt phosphate 3% and nickel phosphate 3%; the mass percentages of the auxiliary agent component in the entire coating liquid are as follows: film-forming auxiliary agent 5%, water-based wetting agent 2%, water-based dispersant 4%, water-based leveling agent 2%, water-based defoaming agent 5%; the rest is deionized water.

[0070] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0071] (1) Preparation of water-based resin component: First, uniformly mix the formulated amount of acrylic resin, polyester resin, epoxy resin, silicone resin, and fluorine resin under stirring at 300 r / min, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol, and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. Then, after the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, leveling agent, film-forming aid, and defoaming agent in turn, and stir at a stirring speed of 600 r / min for 2 hours to obtain a water-based resin.

[0072] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0073] (3) At a rotation speed of 900 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 2 ml / min. After all the addition is completed, the rotation speed is maintained at 900 r / min and stirring is continued for 1-2 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0074] Example 2

[0075] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin and inorganic phosphate. The mass percentages of the aqueous resin component in the entire coating liquid are as follows: 20.4% styrene acrylic resin, 6% polyester resin, 19.6% epoxy resin, 1% ethylene glycol, 1% glycerol, 1.5% silicone resin, 2.3% fluorine resin, 1.2% sodium allyloxyhydroxypropyl sulfonate, 1% OP-10, 1% sodium dodecylbenzenesulfonate, 3% sodium persulfate, and 2% potassium bisulfite; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: 10% aluminum dihydrogen phosphate, 3% phosphoric acid, 3% magnesium dihydrogen phosphate, 3% calcium dihydrogen phosphate, 2% zinc dihydrogen phosphate, 1% strontium phosphate, 1% cobalt phosphate, and 1% nickel phosphate; the mass percentages of the auxiliary agent component in the entire coating liquid are as follows: 5% film-forming auxiliary agent, 2% aqueous wetting agent, 2% aqueous dispersant, 2% aqueous leveling agent, 1% aqueous defoaming agent, and 2% aqueous thickener; the rest is deionized water.

[0076] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0077] (1) Preparation of water-based resin component: First, uniformly mix the formulated amount of styrene acrylic resin, polyester resin, epoxy resin, silicone resin, and fluorine resin under stirring at 300 r / min, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol, and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. After the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, thickener, leveling agent, film-forming aid, and defoamer in turn, and stir at a speed of 600 r / min for 2 hours to obtain a water-based resin.

[0078] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0079] (3) At a rotation speed of 1200 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 1 ml / min. After all the addition is completed, the rotation speed is maintained at 1200 r / min and stirring is continued for 2-4 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0080] Example 3

[0081] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin and inorganic phosphate. The mass percentages of the aqueous resin component in the entire coating liquid are as follows: acrylic resin 10%, styrene acrylic resin 10%, polyester resin 5%, epoxy resin 5%, ethylene glycol 1%, glycerol 1%, silicone resin 1%, fluorine resin 2%, sodium allyloxyhydroxypropyl sulfonate 2%, OP-10 0.5%, sodium dodecylbenzene sulfonate 1%, sodium persulfate 1%, potassium bisulfite 0.5%; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: aluminum dihydrogen phosphate 20%, phosphoric acid 5%, magnesium dihydrogen phosphate 5%, calcium dihydrogen phosphate 5%, zinc dihydrogen phosphate 2%, strontium phosphate 2%, cobalt phosphate 3% and nickel phosphate 3%; the mass percentages of the auxiliary agent component in the entire coating liquid are as follows: film-forming auxiliary agent 5%, aqueous wetting agent 2%, aqueous dispersant 4%, aqueous leveling agent 2%, aqueous defoaming agent 2%; the rest is deionized water.

[0082] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0083] (1) Preparation of water-based resin component: Under the condition of stirring at 300 r / min, firstly uniformly mix the formulated amount of acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin, silicone resin and fluorine resin, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. Then, when the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, leveling agent, film-forming aid and defoaming agent in turn, and stir at 600 r / min for 2 hours to obtain water-based resin.

[0084] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0085] (3) At a rotation speed of 900 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 2 ml / min. After all the addition is completed, the rotation speed is maintained at 900 r / min and stirring is continued for 1-2 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0086] Example 4

[0087] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin and inorganic phosphate. The mass percentages of the aqueous resin component in the entire coating liquid are as follows: acrylic resin 1%, styrene acrylic resin 1%, polyester resin 1%, epoxy resin 1%, ethylene glycol 0.5%, glycerol 0.5%, silicone resin 0.5%, fluorine resin 0.5%, sodium allyloxyhydroxypropyl sulfonate 2%, OP-10 0.5%, sodium dodecylbenzene sulfonate 0.5%, sodium persulfate 0.6%, potassium bisulfite 0.4%; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: aluminum dihydrogen phosphate 20%, phosphoric acid 5%, magnesium dihydrogen phosphate 5%, calcium dihydrogen phosphate 5%, zinc dihydrogen phosphate 4%, strontium phosphate 3%, cobalt phosphate 3% and nickel phosphate 3%; the mass percentages of the auxiliary agent component in the entire coating liquid are as follows: film-forming auxiliary agent 5%, aqueous wetting agent 2%, aqueous dispersant 2%, aqueous leveling agent 2%, aqueous defoaming agent 5%; the rest is deionized water.

[0088] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0089] (1) Preparation of water-based resin component: Under the condition of stirring at 300 r / min, firstly uniformly mix the formulated amount of acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin, silicone resin and fluorine resin, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. Then, when the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, leveling agent, film-forming aid and defoaming agent in turn, and stir at 600 r / min for 2 hours to obtain water-based resin.

[0090] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0091] (3) At a rotation speed of 900 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 2 ml / min. After all the addition is completed, the rotation speed is maintained at 900 r / min and stirring is continued for 1-2 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0092] Example 5

[0093] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin and inorganic phosphate. The mass percentages of the aqueous resin component in the entire coating liquid are as follows: acrylic resin 20%, styrene-acrylic resin 15%, polyester resin 15%, epoxy resin 10%, ethylene glycol 1%, glycerol 1%, silicone resin 1%, fluorine resin 0.5%, sodium allyloxyhydroxypropyl sulfonate 3%, OP-10 1%, sodium dodecylbenzene sulfonate 1%, sodium persulfate 1%, potassium bisulfite 0.5%; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: aluminum dihydrogen phosphate 10%, phosphoric acid 2%, magnesium dihydrogen phosphate 2%, calcium dihydrogen phosphate 2%, zinc dihydrogen phosphate 2%, strontium phosphate 1%; the mass percentages of the auxiliary agent components in the entire coating liquid are as follows: film-forming auxiliary agent 1%, aqueous wetting agent 1%, aqueous dispersant 2%, aqueous leveling agent 2%, aqueous thickener 3%, aqueous defoaming agent 1%; the rest is deionized water.

[0094] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0095] (1) Preparation of water-based resin component: Under the condition of stirring at 300 r / min, firstly uniformly mix the formulated amount of acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin, silicone resin and fluorine resin, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. Then, after the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, leveling agent, water-based thickener, film-forming aid and defoamer in turn, and stir at 600 r / min for 2 hours to obtain water-based resin.

[0096] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0097] (3) At a rotation speed of 1200 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 2 ml / min. After all the addition is completed, the rotation speed is maintained at 1200 r / min and stirring is continued for 2-4 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0098] Example 6

[0099] The invention discloses a non-oriented silicon steel coating liquid, which comprises water-based resin and inorganic phosphate. The mass percentages of the water-based resin component in the entire coating liquid are as follows: 1% acrylic resin, 1% epoxy resin, 0.5% ethylene glycol, 0.5% glycerol, 0.5% sodium allyloxyhydroxypropyl sulfonate, 0.5% OP-10, 0.3% sodium dodecylbenzenesulfonate, 0.3% sodium persulfate, and 0.4% potassium hydrogen sulfite; the mass percentages of the solute components of the inorganic phosphate solution in the entire coating liquid are as follows: 20% aluminum dihydrogen phosphate, 5% phosphoric acid, 5% magnesium dihydrogen phosphate, 5% calcium dihydrogen phosphate, 3% zinc dihydrogen phosphate, 2% strontium phosphate, 3% cobalt phosphate, and 3% nickel phosphate; the mass percentages of the auxiliary agent component in the entire coating liquid are as follows: 5% film-forming auxiliary agent, 2% water-based wetting agent, 7% water-based dispersant, 2% water-based leveling agent, 3% water-based thickener, and 5% water-based defoaming agent; the rest is deionized water.

[0100] The method for preparing the non-oriented silicon steel coating liquid coating comprises the following steps:

[0101] (1) Preparation of water-based resin component: Under the condition of stirring at 300 r / min, firstly uniformly mix the formulated amount of acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin, silicone resin and fluorine resin, and then add the formulated amount of dispersant, sodium allyloxyhydroxypropyl sulfonate, OP-10, sodium dodecylbenzene sulfonate, ethylene glycol and propylene glycol to the resin mixture. Inert gas protection is poured into the reaction device, and the system is heated at 60°C and condensed and refluxed, and stirred at 300 r / min for 3 hours. Then, after the system temperature reaches room temperature, filter it, and then add the formulated amount of wetting agent, thickener, leveling agent, film-forming aid and defoamer in turn, and stir at 600 r / min for 2 hours to obtain water-based resin.

[0102] (2) Preparation of an inorganic phosphate solution: Dissolve the formulated amounts of aluminum dihydrogen phosphate, phosphoric acid, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, strontium phosphate, cobalt phosphate and nickel phosphate in an appropriate amount of deionized water, and stir at 600 r / min at room temperature for 2 h to fully dissolve, thereby obtaining an inorganic phosphate solution.

[0103] (3) At a rotation speed of 1200 r / min, the aqueous resin obtained in step (1) is continuously added to the inorganic phosphate solution obtained in step (2) according to a predetermined ratio and at a flow rate of 2 ml / min. After all the addition is completed, the rotation speed is maintained at 1200 r / min and stirring is continued for 2-4 hours. The non-oriented silicon steel coating liquid is obtained by stirring evenly.

[0104] The compositions provided in Examples 1-6 were used to prepare non-oriented silicon steel, and no floater was used in the preparation process; the preparation results are shown in the following table:

[0105]

[0106]

[0107] It can be seen from the above table that the hot-pressed bonding coating composition provided in the examples of the present application is used as a coating for electrical steel, and the preparation can be successfully completed even without a floater during the preparation process.

[0108] The non-oriented silicon steel prepared by the composition provided in Examples 1-6 was used to prepare the iron core; the product performance results of the iron core are shown in the following table:

[0109] The embodiment tests the surface insulation resistance and coating adhesion of silicon steel according to the national standard GB / T 2522-2007 "Test method for surface insulation resistance and coating adhesion of silicon steel sheets (strips)", wherein the adhesion is divided into A, B, C, and D grades from good to poor.

[0110] A Zeiss scanning electron microscope was used to observe the side and surface of the sample at a magnification of 15,000 times. The thickness of the coating can be seen from the side with an error of ±0.1μm.

[0111] The insulation properties are measured using a Frankin tester (evaluated by interlayer resistance);

[0112]

[0113] It can be seen from the above table that the coating liquid provided in the embodiment of the present application is used as a coating for silicon steel, and the surface has adhesion after heating.

[0114] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0115] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0116] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A non-oriented silicon steel coating liquid, characterized in that: The coating liquid comprises water-based resin, inorganic salt, additive and solvent, wherein the water-based resin is composed of acrylic resin and epoxy resin; The acrylic resin is selected from all-acrylic water-based resin, styrene-acrylic water-based resin, silicone-acrylic water-based resin, acetic acid-acrylic water-based resin, and fluoroacrylic water-based resin; The epoxy resin is a modified copolymer of glycidyl ester epoxy resin; The inorganic salts include inorganic phosphates; The inorganic phosphate is selected from at least one of aluminum dihydrogen phosphate, magnesium dihydrogen phosphate, calcium dihydrogen phosphate, zinc dihydrogen phosphate, manganese dihydrogen phosphate, nickel dihydrogen phosphate and cobalt dihydrogen phosphate; The auxiliary agents include film-forming auxiliary agents, wetting agents and defoaming agents; The mass percentages of the components of the coating liquid are: 40% to 60% of phosphate, 30% to 55% of water-based resin, and the rest are additives and deionized water; The solid content of the water-based resin is 20%-50%; The viscosity of the coating liquid is 9-20S.

2. A non-oriented silicon steel, characterized in that: The non-oriented silicon steel comprises a substrate and a coating attached to at least a portion of the surface of the substrate, wherein the coating is made from the non-oriented silicon steel coating liquid according to claim 1; The coating has a thickness of 0.5-2 μm.

3. A method for preparing non-oriented silicon steel, characterized in that: The method comprises: Obtaining the non-oriented silicon steel coating liquid according to claim 1; Applying the coating liquid to the surface of the substrate, and then baking to obtain silicon steel with a coating; The baking temperature is 300-650°C; The baking time is 20-40s.

4. A method for preparing an iron core, characterized in that: The method comprises: The non-oriented silicon steel according to claim 2 is stamped and then stacked to obtain a semi-finished product; Heating the semi-finished product to solidify the coating on the surface of the non-oriented silicon steel to obtain an iron core; The heating pressure is 2-11 bar; The heating temperature is 200-300°C; The heating time is 5-40 min.

5. An iron core, characterized in that: The iron core is made by the iron core preparation method according to claim 4, and a bonding layer is formed between the silicon steel sheets of the iron core so that there is bonding force between the silicon steel sheets, and the bonding strength between the silicon steel sheets reaches 0.05-0.3Mpa.

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