JP4460312B2 - Non-oriented electrical steel sheet with excellent coating performance, insulating coating treatment agent, and insulating coating treatment method - Google Patents

Description

  The present invention applies a treatment agent that does not contain a Cr compound in the production of non-oriented electrical steel sheets, has excellent paintability in a high-speed line, and is characterized by punching and welding as properties of the insulating film after baking. The present invention relates to a product having an organic-inorganic insulating coating agent having excellent coating properties such as property, adhesion, space factor, and appearance, a processing agent, and an insulating coating forming method using the same.

  As is well known, when a non-oriented electrical steel sheet is used for an iron core of a motor or a transformer, it is punched into a predetermined shape, and then a predetermined number of sheets are stacked, welded, caulked or bonded to form an iron core. At this time, strain annealing is performed as necessary. Usually, the surface of this non-oriented electrical steel sheet is subjected to an electrical insulation coating treatment. For this insulating film, punching, weldability, corrosion resistance, adhesion, space factor, etc. are important in addition to insulation, and if an annealing process is required, adhesion after annealing, insulation, corrosion resistance Etc. are also important.

  Conventionally, as an insulating coating agent, an inorganic type, an organic type, or an organic-inorganic mixed type coating has been applied according to use conditions and purposes. In general, inorganic coatings are excellent in heat resistance and weldability but inferior in punchability. On the other hand, in the case of an organic coating, punching and adhesion are excellent, but heat resistance is poor and weldability is inferior. In order to solve both of these drawbacks, organic-inorganic coatings capable of obtaining intermediate characteristics have been used.

  As an organic-inorganic coating, in Patent Document 1, when forming a mixed coating of phosphoric acid-based or chromic acid-based one or more types and an organic resin, organic resin particles are added to the treatment liquid to form a surface. There has been proposed an insulating film forming method with a roughness of 2 to 10 μm Hmax and excellent in punchability and weldability.

In Patent Document 2, as a method for producing a non-oriented electrical steel sheet having excellent coating properties after strain relief annealing, one or two kinds of oxides selected from CrO ₃ 100 parts by mass, Al, Mg, Ca, and Zn are disclosed. One or two or more kinds of fine particle emulsion resin solutions 10 to 60 of acrylic, styrene, vinyl acetate, and / or a copolymer shell thereof adjusted to 20 to 40 parts by mass and a particle diameter of 0.2 to 0.5 μm. 1 part or more of methyl methacrylate, polyacrylonitrile, polystyrene, cellulose, silicon, melamine, phenol, poval resin and / or copolymer thereof, and cross-linked product adjusted to 1 to 50 μm by mass part 2 to 30 parts by mass is disclosed, and thereby, the punchability and weldability are good, and the lubricity, insulation, and corrosion resistance after strain removal are remarkably improved. It is stated that.

  Patent Document 3 proposes a coating agent that does not contain a Cr compound similar to the present invention. According to the above-mentioned publication, an aqueous solution containing Al phosphate and a synthetic emulsion resin of PH1 to 3 are mixed, assuming the proportion of both nonvolatile components, and further, coarse particles having an average particle diameter of 5 to 15 μm are mixed in the aqueous solution. A coating composition to which a crosslinked resin powder is added is proposed, and it is described that the film is formed at a heating temperature of 250 to 500 ° C. as the treatment condition.

  In Patent Document 4, similarly, a treatment agent not containing a Cr compound is selected from 6 to 56 parts by mass of an emulsion resin and 100, parts by mass of primary phosphoric acid Al in terms of solid content and Al, Mg, Ca, Zn as an additive. A surface treatment agent for non-oriented electrical steel sheet containing 0.5 to 10 parts by mass of organic acid salt is proposed. According to this, it is stated that the addition of an organic acid salt improves the moisture absorption resistance after baking and improves the seizure resistance during strain relief annealing.

  However, in these prior arts, the problem of wettability, moisture absorption resistance, and seizure resistance of the insulating coating is not yet sufficient depending on the use conditions in the consumer, and improvement is desired.

JP 52-33846 A JP-A-3-240970 Japanese Patent Laid-Open No. 5-78855 JP-A-11-131250

  It is important to develop an insulating coating agent that does not contain Cr because of problems in the working environment during manufacture and use of electrical steel sheets. However, the conventional insulating coating containing no Cr has a problem of moisture absorption due to a small amount of free phosphoric acid remaining in the coating and seizure during annealing. Furthermore, problems such as denseness and poor paintability due to the unique film filling effect of the Cr compound have not been solved. In particular, the problems of punchability, weldability and appearance defects brought about by the problem of wettability of liquid and the problem of free phosphoric acid in the recent high-speed coating / baking processing line are strongly desired to be further improved.

The present invention has been devised to improve solution wettability, moisture absorption, seizure, weldability, punchability, and the like in a phosphate-emulsion resin-based insulating coating containing no Cr compound. Thus, the object of the present invention is to provide a non-oriented electrical steel sheet having a coating property equivalent to or better than that of a conventional Cr compound-containing insulating coating agent, its insulating coating agent, and a method for forming a coating.
(1) Al and / or Ca phosphate, emulsion resin having a particle size of 0.04 to 10 μm, water-soluble organic compound, hydroxide, oxide 1 of the above compound selected from Ni, Co, Sr, and Fe It is treated with a coating agent in which 0.1 or 15 parts by weight of two or more seeds are blended per 100 parts by mass of phosphate, and the organic component in the coating component is 5 to 5 in terms of solid content per 100 parts by weight of phosphate. A non-oriented electrical steel sheet having 40 parts by mass and a surface roughness Ra value of 0.10 to 0.50 μm.
(2) The non-oriented electrical steel sheet according to (1), wherein an emulsion resin containing an ultrafine emulsion resin having a particle diameter of 0.04 to 0.19 μm in a mass ratio of 20% or more of the total emulsion resin is used.
( 3 ) 5 to 40 parts by mass of a total of one or more emulsion resins having a particle diameter of 0.04 to 10 μm and a water-soluble organic compound with respect to 100 parts by mass of the primary phosphate of Al and / or Ca, As a hydroxide or oxide, a water-soluble organic compound selected from Ni, Co, Sr, and Fe , a hydroxide, a particle having an average particle diameter of 3 μm or less, or a total of one or more of water-soluble substances An insulating coating agent for a non-oriented electrical steel sheet, comprising 0.5 to 10 parts by mass.
( 4 ) As an emulsion resin, an ultrafine particle emulsion resin having a particle size of 0.04 to 0.19 μm is composed of 20% or more of the total emulsion resin by mass ratio, and the remainder is a coarse particle emulsion resin having a particle size of 0.20 to 10 μm. ( 3 ) Insulating coating agent for non-oriented electrical steel sheet.
( 5 ) As emulsion resin, one or two or more of acrylic, styrene, vinyl acetate, polystyrene, polypropylene, polyamide, polycarbonate, melamine, polyurethane, alkyd, isocyanate, epoxy resin having a Tg of 20 to 100 ° C. is used to constitute the resin. The insulating coating agent for non-oriented electrical steel sheets according to ( 3 ) or ( 4 ), wherein an emulsifier is added in an amount of 0.1 to 8% by weight of the resin solid content.
( 6 ) The insulating coating agent for non-oriented electrical steel sheets according to any one of ( 3 ) to ( 5 ), wherein the hydroxide or oxide is a colloidal material that is stable as an aqueous solution having a particle diameter of 500 nm or less.
( 7 ) Insulating coating agent for non-oriented electrical steel sheet, characterized in that the form of colloidal material of ( 6 ) is a composite colloidal material of each metal element compound and / or SiO ₂ or Al ₂ O ₃ .
( 8 ) The insulating coating agent of any one of ( 3 ) to ( 7 ) is applied to the surface of the non-oriented electrical steel sheet after finish annealing so that the mass after drying is 0.5 to 7.0 g / m ² per side. And an insulating film treatment method for a non-oriented electrical steel sheet, characterized by baking at 160 to 300 ° C.

  According to the present invention, a conventional Cr compound-containing insulating coating is improved by improving the wettability, moisture absorption, seizure, weldability, punching and the like of a solution in a phosphate-emulsion resin-based insulating coating containing no Cr compound. It is possible to provide a non-oriented electrical steel sheet having a coating property equal to or better than that of the agent, an insulating coating agent, and a method for forming the coating.

  The inventors of the present invention have found that the coating process after baking and the poor coating property in the high-speed coating / baking line, which is a defect in the treatment process and coating characteristics in the semi-organic insulating coating mainly composed of phosphate-emulsion resin containing no Cr compound. In order to solve the problems of hygroscopicity, seizure during annealing, and punching and weldability problems caused by this, we worked on improving the liquid composition and baking conditions. In other words, the conventional insulating coating technology has a problem in that a high-speed line, particularly high-speed coating such as 150 m / min or more, does not have sufficient liquid coating properties and makes uniform coating difficult and a stable coating film cannot be obtained. It was. For this reason, it is necessary to work conditions such as a low speed plate that impedes productivity and an increase in coating amount in order to improve paintability. Further, in the case of a coating composition that does not contain a Cr compound as a coating component as in the present invention, due to the problem of free phosphoric acid remaining in the coating, such as stickiness of the coating after baking or increase in seizure at the time of strain relief annealing in the customer, etc. There's a problem.

  The present inventors have studied solution components and processing conditions in order to solve such problems. As a result, an emulsion resin having a particle size of 0.04 to 10 μm and a water-soluble organic compound are used as the main component with respect to the phosphate of Al and / or Ca, and preferably the emulsion resin is a composite of ultrafine particles and coarse particles. It was also found that by controlling Tg within a certain range, the paintability of the solution was extremely excellent and the film performance was greatly improved.

Furthermore, by adding one or more of Ni, Co, Sr, and Fe organic acid salt, ultrafine hydroxide, and oxide to this solution, the hygroscopicity, corrosion resistance and strain relief annealing of the baked film It has been found that a remarkable improvement effect of seizure resistance can be obtained and the present invention has been successfully developed. The present invention is described in detail below.

  In the present invention, first, the insulating film treating agent is characterized, and the insulating film composition of the non-oriented electrical steel sheet having a beautiful and uniform film obtained by the treating agent is fundamental. That is, it consists of a dry film of a treatment agent containing, as main components, an Al and / or Ca phosphate, an emulsion resin having a particle size of 0.04 to 10 μm, and a water-soluble organic compound, and the organic component has a solid mass. 5 to 40 parts by mass, and the non-oriented electrical steel sheet has an insulating coating surface roughness of 0.10 to 0.50 in terms of average roughness Ra.

  At this time, as the emulsion resin, by containing 20% or more of the ultra-fine emulsion resin having a particle size of 0.04 to 0.19 μm by mass ratio, the surface appearance and adhesion, weldability, corrosion resistance, etc. An excellent product is obtained.

Furthermore, as an additive, organic acid salt or hydroxide selected from among Ni, Co, Sr, and Fe , one or two or more kinds of particles having a mean particle diameter of 3 μm or less or a water-soluble substance is added per 100 parts by mass of phosphate. By adding 5 to 15 parts by mass, it is possible to obtain a film that is more excellent in seizure annealing in addition to the denseness, stickiness, and corrosion resistance of the film after baking.

  Moreover, as an emulsion resin component used by this invention, Tg20-100 degreeC acrylic, styrene, vinyl acetate, a polystyrene, a polypropylene, a polyamide, a polycarbonate, a melamine, a polyurethane, an alkyd, an isocyanate, an epoxy resin 1 type, or 2 or more types Is used. A copolymer or a crosslinked product of these resins may be used. Tg is a glass transition temperature.

  Ultra-fine emulsion resin and water-soluble resin have improved coatability and uniform coating of organic components on the surface of the insulating film, and since the film is made uniform, the heat resistance, denseness, insulation and corrosion resistance of the insulating film Contributes to improvement of properties. In particular, the ultrafine particle emulsion resin remarkably improves the coating and adsorbing properties on the steel sheet surface, and combined with the effect of the emulsifier layer applied in the production process of the ultrafine particle emulsion resin, the particle size is 0.20 to 0.00. Compared with the case of a commercially available emulsion resin having a thickness of 50 μm, it brings about an epoch-making improvement effect in paintability. Thereby, extremely good coating workability can be obtained even in the coating process of the high-speed line. In particular, when the particle size is 0.04 to 0.14 μm, the effect of improving the wettability by the ultrafine particles is large, and the wettability to the steel plate that cannot be obtained even if a surfactant is added to a normal emulsion resin. The improvement effect is obtained.

  In addition, in the present invention, a uniform coating film surface is enabled by the effect of improving the coatability by the ultrafine particle emulsion resin and the effect of controlling the uniform spherical unevenness by the coarse particle emulsion resin used in combination. A stability improvement effect is achieved. This particle diameter is preferably 0.20 to 10 μm. In particular, when an emulsion resin having a coarse particle size is to be used, a stable solution can be prepared by using a coarse particle emulsion resin such as Chemipearl W type or A type manufactured by Mitsui Chemicals. By using a coarse emulsion resin in combination, fine protrusions on a uniform surface are generated, contributing to improvements in slipperiness, weldability and the like.

  By using the emulsion resin having the above configuration, the surface roughness of the steel sheet after the treatment with the insulating coating agent can be stably controlled with an Ra value of 0.10 to 0.50 μm.

  Further, the coating composition containing no Cr compound of the present invention is disadvantageous in terms of hygroscopicity, corrosion resistance, weldability, etc. due to the effect of free phosphoric acid. As a measure for weldability, a coarse particle emulsion resin is used in combination. Since the fine uneven shape on the surface made of this coarse particle emulsion resin does not produce an aggregate as in the case of powder addition, a uniform uneven shape is formed. As a result, the slipperiness of the insulating coating is improved as well as the weldability. And it is possible to achieve both excellent wettability and coating properties by using a resin composition that contains 20 parts by mass or more of the total emulsion resin of ultrafine particle emulsion resin having a particle size of 0.04 to 0.19 μm.

  Although it does not specifically limit as a water-soluble organic compound, The organic compound containing OH is excellent in workability | operativity. Typical examples include butyl alcohol, cyclohexanol, furfuryl alcohol, benzyl alcohol, ethylene glycol, propylene glycol, hexylene glycol, glycerin, polyvinyl alcohol, and ponyvinyl butyral. These water-soluble organic compounds form a uniform organic material layer over the entire coating layer so as to sew between the dotted organic material layers made of ultrafine particles and coarse particle emulsion resin. As a result, combined with the effect of the ultrafine particles, the punchability improving effect can be further enhanced. Moreover, it reacts with a part of free phosphoric acid and contributes to improvement of stickiness, corrosion resistance, seizure property, and the like.

Another feature of the present invention, Ni as an additive, Co, Sr, Fe or al organic acid salt selected, hydroxides, one having an average particle diameter of 3μm or smaller particles or water of oxides or two The above is to add. As described above, in phosphate-based coatings that do not contain Cr compounds, it is important to control free phosphoric acid and to make the coating denser, so that moisture absorption (stickiness), corrosion resistance, seizure resistance, and weldability are important. How to improve is an important issue. The present inventors have proceeded improvement studies with enormous test results, Ni, Co, Sr, Fe or al organic acid salt selected, hydroxides, an average particle diameter of 3μm or smaller particles or water of oxides By adding one kind or two or more kinds, the inventors have found dramatic moisture absorption resistance (stickiness), corrosion resistance, seizure resistance, and weldability improvement effects.

  In particular, as an additive, in addition to a water-soluble organic acid salt, a hydroxide having a particle diameter of 500 nm or less, or a colloidal material of an oxide has a large effect of preventing dissolved phosphorus and densifying the coating. As a result, an extremely large improvement effect is obtained in corrosion resistance, seizure resistance during annealing, and the like.

  In the additive addition, a significant improvement is seen at 0.1 to 15 parts by mass per 100 parts by mass of the phosphate.

  Since the amount added should be controlled according to the amount of free phosphoric acid, it should be added according to the molar ratio represented by Al, Ca oxide (hydroxide) / phosphoric acid at the time of phosphate production and the drying conditions. It is more preferable.

  In applying the solution of the present invention, a surfactant which is a known technique may be further added. In particular, when the application conditions (roll conditions, steel sheet surface properties, etc.) are inferior, some auxiliary effects are exhibited.

  As a baking condition of the insulating coating agent of the present invention, a baking process is performed at a plate temperature of 160 to 300 ° C.

The film thickness is determined according to the purpose of use and application, but when the liquid of the present invention is applied, uniform coating is possible within the range of 0.5 to 7.0 g / m ² .

  Next, the reason for limitation in the present invention will be described.

  The product of the present invention is achieved by using the following treatment agent.

  The first feature of the treating agent in the present invention is an organic component comprising one or more of an emulsion resin and a water-soluble resin having a particle size of 0.04 to 10 μm with respect to 100 parts by mass of Al and / or Ca phosphate. It is characterized by adding in the range of 5 to 40 parts by mass. As a result, a product having an average roughness Ra of 0.1 to 0.5 μm is obtained as the surface roughness after baking.

  At this time, as the emulsion resin, an emulsion resin containing 20% or more of the total emulsion resin by mass ratio with an ultrafine particle resin having a particle size of 0.04 to 0.19 μm is used, and the balance is 0.20 to 10 μm. As a result, it is possible to obtain coating properties having excellent paintability, appearance, adhesion, weldability, punchability, and the like. The particle diameter of the emulsion resin may be adjusted depending on whether it has a uniform particle size distribution or a broad particle diameter.

  First, the phosphate used in the present invention is limited to Al and / or Ca. This is because, in the surface treatment agent for non-oriented electrical steel sheets baked at low temperature, it is difficult to increase the film thickness at a low temperature in a short time with components other than Al and Ca, and the heat resistance is poor.

  As the particle diameter of the emulsion resin, one or more of 0.04 to 10 μm is applied. In the present invention, a certain amount of the ultrafine particle emulsion resin is blended in order to obtain good paintability and an effect of improving the film properties. This is because the ultrafine particle emulsion resin can provide a very good improvement effect of paintability. In particular, this effect is remarkable when an ultrafine emulsion resin having a particle size of 0.04 to 0.19 μm is contained in a mass ratio of 20% or more of the total emulsion resin. This is due to the remarkable improvement in paintability due to a decrease in the surface contact angle of the solution by the ultrafine particle emulsion resin.

  By combining this ultrafine particle emulsion resin and a 0.20 to 10 micron coarse particle emulsion resin, the particles of the coarse particle emulsion resin are uniformly dispersed on the surface of the steel sheet to form a fine uneven shape uniformly, and the entire surface is made of ultrafine particles. A film layer covered with an emulsion resin is uniformly formed. By this uniform fine emulsion resin layer, punching and adhesion improving effects are obtained, and free phosphoric acid is reduced.

  The water-soluble organic compound improves the punchability by uniformly increasing the organic substance concentration on the surface of the coating film, like the fine particle emulsion resin. Moreover, weldability is improved by the uniform uneven | corrugated shape by a 0.2-10 micrometer coarse particle emulsion resin. Such an effect is remarkably superior to the non-uniform surface obtained by adding the coarse particle resin powder in the prior art.

  In this case, the blending ratio of the emulsion resin and the water-soluble organic substance is 5 to 40 parts by mass per 100 parts by mass of the phosphate. If it is less than 5 parts by mass, the punchability is lowered. On the other hand, if it exceeds 40 parts by mass, it is limited because degradation of weldability increases even in the composition of the present invention due to decomposition gas due to a large amount of organic matter.

  In this case, as the emulsion resin, it is preferable to contain an emulsion resin having a particle size of 0.04 to 0.19 μm in a mass ratio of 20% or more in the total emulsion resin. This is because if it is less than 20%, the effect of improving paint finish is not sufficiently exhibited.

  In addition, the lower limit of the particle size of the ultrafine emulsion resin is set to 0.04 μm because the required amount of emulsifier increases when the particle size becomes too small, such as less than 0.04 μm, and the foaming property in the coating process increases. This makes the operation difficult in the application process. Moreover, it is because it is not preferable also in terms of resin manufacturing cost. The coarse particle emulsion resin having a particle size of 0.20 to 10 μm is added according to the amount of the fine particle emulsion resin. In the case of a coarse particle emulsion resin, if the particle diameter is 10 μm or more, the emulsion resin itself has poor stability in the solution, and there is a problem due to sedimentation. More preferable addition conditions are when the particle size is 0.35 to 0.7 μm and 30 to 60 parts by mass in the total resin is contained. Within this range, excellent coating performance with a very good balance such as paintability, punchability, weldability, adhesion, and slipperiness is obtained, and coating performance comparable to conventional Cr compound-containing coatings. Demonstrated.

  As the component of the emulsion resin, one or more emulsion resins having a Tg of 20 to 100 ° C. are used, and the amount of the emulsifier constituting the resin is 0.1 to 8% by weight of the resin solid content. When Tg is less than 20 ° C., a blocking phenomenon in which the insulating coating is fused at a low temperature is likely to occur, and since the coating hardness is weak, the surface of the insulating coating is easily wrinkled in the iron core processing step. In extreme cases, a powdering phenomenon occurs with a slitter or the like, causing problems. On the other hand, when the temperature exceeds 100 ° C., the film forming property is lowered, and depending on the baking conditions, the denseness and smoothness of the coating film are reduced, and the surface gloss is reduced or the coating performance is affected. As a method for adjusting Tg, for example, in the case of an acrylic resin, the mixing ratio of an acrylic resin such as methyl methacrylate, butyl acrylate, and ethyl acrylate is changed.

  As the emulsion resin component, one or more of acrylic, styrene, vinyl acetate, polystyrene, polypropylene, polyamide, polycarbonate, melamine, polyurethane, isocyanate, and epoxy resin are used, and these resin components are inexpensive. An insulating coating having excellent coating performance can be obtained.

In the production of emulsion resin, polyoxyethylene nonylphenol ether, polyoxyethylene nonylphenol ether, sodium dodecyl benzene sulfonate, polyoxyethylene oleyl ether sulfate Na, polyoxyethylene nonylphenol ether sulfate NH ₄ , sulfosuccinic acid as emulsifiers One kind or two or more kinds of ethoxylated alcohol of dinatrium, ethoxylated nonylphenol half ester of disodium sulfosuccinate, mono- and di-dodecyldiphenyloxide disulfonate, EO adduct of acetylenediol and the like are used.

  The surfactant is used in an appropriate amount depending on the particle size. In the ultrafine particle emulsion resin of the present invention, by using an appropriate amount of these emulsifiers, the stability and good coatability of the resin particles can be obtained. With the resin particle diameter of the present invention, it is preferably produced at 0.1 to 8% per resin component. If it is less than 0.1%, the stability and paintability of the emulsion resin particles cannot be obtained. On the other hand, if it exceeds 8%, the coating workability becomes difficult due to the foaming property, and the film surface defect may be caused by bubbles.

Next, one or more organic acid compounds, hydroxides and oxides having a water solubility of Ni, Co, Sr, and / or Fe and / or a particle size of 3 μm or less are 0.1 per 100 parts by mass of phosphate. It is added at a ratio of ˜15 parts by mass. These organic acid compounds, hydroxides, oxides, and the like react with free phosphoric acid during the baking process or in the strain relief annealing to produce stable phosphides. A part of the Ni, Co, Sr, Fe metals element is incorporated into the coating structure, resulted in a filling effect similar coating porous portions and when Cr is added, a new action to modify the dense film structure Bring. As a result, stickiness due to free phosphoric acid, corrosion resistance deterioration, seizure during annealing, and the like are eliminated.

It can be seen that if these additives are used, the remarkably superior improvement effect can be obtained as compared with the case where the organic acid salt of Al, Mg, Ca, Zn described in Patent Document 4 as the prior art is added. It was. In addition to the stabilization of the free phosphoric acid produced in this cited example, a filling action by an additive element occurs, and an improvement effect superior to conventional addition of a Cr compound can be obtained depending on the addition conditions. The particle diameter of the colloidal substance of Ni, Co, Sr, Fe hydroxide or oxide is preferably 500 nm or less. This is because the reaction with free phosphoric acid and the film filling effect are excellent. In particular, an extremely excellent result was obtained with an ultrafine colloidal material of less than 50 nm.

  When such a colloidal material is added, the same effect can be obtained by adding a colloidal material such as colloidal material such as colloidal silica or colloidal alumina in addition to the respective colloidal materials of hydroxide and oxide. If the addition amount is less than 0.1 parts by mass, the effect of free phosphoric acid may not be sufficiently suppressed, so that the amount is limited. On the other hand, if it exceeds 15 parts by mass, the appearance may be impaired, and other coating performance may be affected.

The percentage of the total resin of ultra fine particle emulsion resin in the present invention was 20% or more, the Ni, Co, Sr, water-soluble and / or 3μm less fine hydroxides by Fe, free of an organic acid salt This is because the phosphoric acid suppression effect is enormous, and even when the coarse particle emulsion resin is not included, the coating properties are considerably excellent.

  Next, when performing the insulating film baking process using the present invention, in the line where continuous annealing and coating are performed, after the cold-rolled coil of the final plate thickness is washed and finish-annealed, the insulating film treating agent is diluted with the solution As a result, it is applied and baked by a coating apparatus such as a rubber roll. The baking process is performed at 160 ° C to 300 ° C. When the inorganic component is based on phosphate as in the present invention, it is necessary to lower the baking temperature. If it is less than 160 ° C., the film formation is not sufficient, the stabilization reaction of free phosphoric acid does not occur sufficiently, and stickiness, corrosion resistance and seizure property during annealing are lowered. On the other hand, when the temperature exceeds 300 ° C., decomposition and burnout of organic components occur, which not only impairs the appearance and punchability but also impairs the surface appearance.

The coating amount is 0.5 to 7.0 g / m ² per side by mass after drying. The film thickness is determined according to the purpose of use. If it is less than 0.5 g, the steel sheet coating may be insufficient, and the corrosion resistance and punchability are reduced. On the other hand, if it exceeds 7.0 g, an effect of improving punchability and corrosion resistance can be obtained, but it is limited to cause problems of deterioration in weldability and increase in processing cost.

After annealing a non-oriented electrical steel sheet cold rolled coil with a thickness of 0.5 mm containing Si: 0.25%, Al: 0.003%, Mn: 0.25% in a continuous annealing line, As shown in Table 1, an insulating film agent using an emulsion resin having a Tg of 40 ° C. with a modified particle size as shown in Table 1 was applied at a dry weight of 1.5 g / m ² (per one side), and a reaching plate Baking treatment was performed at a temperature of 200 ° C. The line speed at this time is 180 m / min. Met. Thereafter, a sample was cut out from the product and investigated for coating performance. The results are shown in Table 2.

  As a result of this test, all the materials coated with the insulating coating of the present invention showed very good paintability in a high-speed coating test, and formed a uniform insulating coating with extremely excellent gloss. Also in the film properties, good corrosion resistance, seizure resistance, weldability, and punchability were obtained. In particular, it was good when an emulsion having a particle size of 0.15 μm or less was used, and when an emulsion having a smaller particle size was combined, the appearance and punchability were excellent.

  However, Comparative Example 1 with a small amount of emulsion resin had extremely poor corrosion resistance, seizure resistance, and punchability, and Comparative Example 2 with a large amount of resin resulted in slightly poor weldability. In addition, when an emulsion resin having a particle size of only 0.5 μm is used, the paintability is slightly poor and the gloss is dull, and the punching property is inferior to that of the composite of the ultrafine particle emulsion of the present invention. It became.

Using the same material as in Example 1, the same treatment was performed in a continuous annealing line. A solution obtained by adding 4 g of glycerin as a water-soluble organic compound to 85 parts by mass of primary phosphoric acid Al and 15 parts by mass of primary phosphoric acid Ca on the surface of the steel sheet is used as a reference solution, and emulsion resins having different particle sizes are used as shown in Table 3. Then, a solution to which an organic acid salt of Ni, Co, Sr, Fe , a hydroxide or a colloidal substance was added as an additive was dried and applied at a mass of 1.2 g / m ^{2 and} baked at 250 ° C. Thereafter, a sample was cut out from the coil, and the coating performance was evaluated. The results are shown in Table 4.

  As a result of this test, the material coated with the insulating coating based on the ultrafine particle emulsion and the coarse particle emulsion of the present invention showed very good wettability in the high-speed coating test as in Example 1. A uniform insulating film with excellent gloss was formed. In particular, when a Fe, Co, Ni, or Sr compound was added, a good coating appearance was obtained. Also in the film properties, the addition of organic acid salts such as Ni, Co, Sr, and Fe and the addition of hydroxide resulted in good corrosion resistance and extremely excellent seizure resistance during strain relief annealing.

In particular, the addition of a colloidal hydroxide Fe, a colloidal oxide Fe, and a composite colloidal material of SiO ₂ -hydroxylated Fe was very effective in corrosion resistance and sticking resistance.

However, even in the treatment agent of the present invention, those Tg of the emulsion resin is 0 ℃ and lower were observed adhesion events of the coating in warm called blocking.

  On the other hand, in the Cr compound-containing coating of the comparative example, a lot of spotted patterns were observed as in Example 1, and the uniformity, corrosion resistance, and punchability of the insulating coating were considerably inferior to those of the present invention.

(A), (b), (c) is a figure which shows the method of evaluating the seizure property in strain relief annealing, and its order.

Claims (8)

Al and / or Ca phosphate, emulsion resin having a particle size of 0.04 to 10 μm, water-soluble organic compound, hydroxide, oxide , one or two of the above compounds selected from Ni, Co, Sr, and Fe The seed component or more is treated with a coating agent containing 0.1 to 15 parts by mass per 100 parts by mass of phosphate, and the organic component in the coating component is 5 to 40 parts by mass in terms of solid content per 100 parts by mass of phosphate. A non-oriented electrical steel sheet having a surface roughness Ra of 0.10 to 0.50 μm. Non-oriented electrical steel sheet 請 Motomeko 1 wherein you characterized by using an emulsion resin containing ultrafine emulsion resin particle size 0.04~0.19μm at a mass ratio of 20% or more of the total emulsion resin. 5 to 40 parts by mass in total of one or more emulsion resins having a particle diameter of 0.04 to 10 μm, water-soluble organic compounds, and hydroxides with respect to 100 parts by mass of primary phosphate of Al and / or Ca In addition, the oxide is a water-soluble organic compound selected from Ni, Co, Sr and Fe , a hydroxide, a particle having an average particle diameter of 3 μm or less, or a total of one or two or more of water-soluble substances. An insulating coating agent for non-oriented electrical steel sheets, characterized by comprising 10 to 10 parts by mass. The emulsion resin is characterized by comprising an ultrafine emulsion resin having a particle size of 0.04 to 0.19 μm in a mass ratio of 20% or more of the total emulsion resin and the balance being a coarse particle emulsion resin having a particle size of 0.20 to 10 μm. The insulating coating agent for non-oriented electrical steel sheets according to claim 3 . As an emulsion resin, an emulsifier that constitutes a resin using one or more of acrylic, styrene, vinyl acetate, polystyrene, polypropylene, polyamide, polycarbonate, melamine, polyurethane, alkyd, isocyanate, and epoxy resin having a Tg of 20 to 100 ° C. The insulating coating agent for non-oriented electrical steel sheet according to claim 3 or 4 , wherein 0.1 to 8% of resin solid content is added by mass ratio. The insulating coating agent for a non-oriented electrical steel sheet according to any one of claims 3 to 5 , wherein the hydroxide or oxide is a colloidal material that is stable as an aqueous solution having a particle diameter of 500 nm or less. An insulating coating agent for non-oriented electrical steel sheets, wherein the colloidal material according to claim 6 is a composite colloidal material of each elemental metal compound and / or SiO ₂ or Al ₂ O ₃ . Finish non-oriented electrical steel sheet after annealing the insulating coating agent according to any one of claims 3-7 and coated to a per side 0.5~7.0g / m ² after drying mass An insulating film treatment method for a non-oriented electrical steel sheet, characterized by baking at 160 to 300 ° C.

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