Title of invention: Coating liquid for forming an insulating coating for grain-oriented electrical steel sheets, and method for producing grain-oriented electrical steel sheets Technical field [0001] 　The present invention relates to a coating solution for forming an insulating coating for grain-oriented electrical steel sheets and a method for producing grain-oriented electrical steel sheets. 　The present application claims priority based on Japanese Patent Application No. 2017-218506 filed in Japan on November 13, 2017, the contents of which are incorporated herein by reference. Background technology [0002] 　A grain-oriented electrical steel sheet is a steel sheet having a crystal structure having a (110)[001] orientation as a main orientation and usually containing 2 mass% or more of Si. Its main use is as an iron core material for transformers and the like, and in particular, there is a demand for a material with a small energy loss during transformation, that is, a material with a low iron loss. [0003] 　Although not particularly limited, a typical manufacturing process of the grain-oriented electrical steel sheet is as follows. First, a slab containing 2% by mass to 4% by mass of Si is hot rolled to anneal the hot rolled sheet. Next, decarburization annealing is performed by performing cold rolling one or more times with intermediate annealing between them to obtain a final plate thickness. After this, an annealing separator is applied and final finishing annealing is performed. As a result, a crystal structure whose main orientation is the (110)[001] orientation is developed, and a finish annealing film is formed on the surface of the steel sheet. For example, when an annealing separating agent mainly containing MgO is used , a finish annealing film mainly containing Mg 2 SiO 4 is formed on the surface of the steel sheet . Finally, the coating liquid for forming the insulating film is applied and baked, and then shipped. [0004] 　The grain-oriented electrical steel sheet has a property that iron loss is improved by applying tension to the steel sheet. Therefore, by forming an insulating film made of a material having a thermal expansion coefficient smaller than that of the steel sheet at a high temperature, tension is applied to the steel sheet and iron loss can be improved. [0005] 　Conventionally, various coating liquids for forming an insulating film on a magnetic steel sheet are known (for example, see Patent Documents 1 to 11). Prior art documents Patent literature [0006] Patent Document 1: Japanese Unexamined Patent Publication No. 48-039338 Patent Document 2: Japanese Examined Japanese Patent Publication No. 54-143737 Unexamined Patent Document 3: Japanese Unexamined Patent Publication No. 2000-169972 Patent Document No. 4: Japanese Unexamined Patent Publication 2000- 178760 gazette Patent document 5: International publication 2015/115036 Patent document 6: Japanese Unexamined Patent Publication No. 06-065754 Patent Document 7: Japanese Unexamined Patent Publication No. 06-065755 Patent Document 8: Japanese Unexamined Patent Publication No. 2010-043293 JP Patent Document 9: Japanese Patent 2010-037602 JP Patent Document 10: Japanese Patent 2017-075358 JP Patent Document 11: WO 2010/146821 Summary of the invention Problems to be Solved by the Invention [0007] 　The insulating film obtained by baking the coating liquid composed of colloidal silica, primary phosphate and chromic acid disclosed in Patent Document 1 is excellent in various film properties such as tension. [0008] 　However, the coating liquid for forming the insulating film contains hexavalent chromium, and therefore, there is a facility consideration in order to improve the working environment in the insulating film forming process of the grain-oriented electrical steel sheet. Therefore, development of a coating solution for forming an insulating film of a grain-oriented electrical steel sheet, which does not contain hexavalent chromium and is excellent in various film properties such as tension, has been desired. [0009] 　For example, Patent Documents 2 to 5 describe a coating liquid for forming an insulating film of a grain-oriented electrical steel sheet, which is mainly composed of colloidal silica and primary phosphate, and is replaced with chromic acid and other additives. Has been done. However, the film tension of the insulating film obtained by the coating liquid for forming an insulating film using an additive other than chromic acid, which does not contain chromic acid, is the film thickness of the insulating film obtained by the coating liquid for forming an insulating film containing chromic acid. Less than tension. In addition, all the additives used in these techniques are more expensive than chromic acid. [0010] 　On the other hand, the insulating film forming coating solutions described in Patent Documents 6 and 7 are formed by a mixture of alumina sol and boric acid. The film tension of the insulating film formed by baking this coating liquid is significantly higher than that of the insulating film obtained by baking the above-mentioned coating liquid composed of colloidal silica, primary phosphate and chromic acid. Is obtained. However, this insulating film has poor corrosion resistance. Further, the price of the alumina sol as a raw material is expensive. [0011] 　Therefore, hydrous silicate (clay mineral) powder has been attracting attention as a material that can be obtained at a relatively low cost and that may have a large film tension after baking. 　For example, Patent Document 8 discloses a coating liquid containing hydrous silicate powder and primary phosphate. Further, Patent Document 9 discloses a coating liquid composed of hydrous silicate powder, primary phosphate and colloidal silica. Further, Patent Document 10 discloses a coating liquid composed of kaolin, which is a kind of hydrous silicate, and lithium silicate. The insulating coating obtained by baking the coating liquid described in these documents is the same as or better than the insulating coating obtained by baking the coating liquid composed of colloidal silica, primary phosphate and chromic acid. Tension is obtained. Further, the obtained grain-oriented electrical steel sheet has excellent iron loss. [0012] 　However, according to the present inventors, the insulating films formed by these coating liquids are not dense. As a result, the use of these coating liquids may result in a poor space factor when the grain-oriented electrical steel sheets after forming the insulating film are laminated to form an iron core, and the corrosion resistance and water resistance of the insulating film. Was found to be insufficient. [0013] 　On the other hand, Patent Document 11 relating to an insulating film of a non-oriented electrical steel sheet discloses a mixed solution containing a metal phosphate and a silicate filler having an average particle size of 2 μm or more. Then, as a method of forming an insulating film of an electromagnetic steel sheet, a method of mixing phosphate with a silicate filler having an average particle size of 2 μm or more and baking at 250° C. to 450° C. is described. In this technique, the silicate is added as a filler in the insulating film, and it is necessary that the original form is left in the insulating film after baking. Therefore, silicate having a large average particle size is used. In addition, since the baking temperature is low, it is difficult to obtain a high film tension, and it is not suitable for application to grain-oriented electrical steel sheets. Furthermore, since a silicate filler having an average particle size of 2 μm or more is used, it is difficult to obtain sufficient film characteristics. [0014] 　The object of the present invention is a grain-oriented electrical steel sheet having a large film tension, obtaining a film property excellent in space factor, corrosion resistance and water resistance, and having excellent iron loss, even without using a chromium compound. An object of the present invention is to provide a coating solution for forming an insulating film, and a method for manufacturing a grain-oriented electrical steel sheet. Means for solving the problems [0015] <1> A coating liquid for forming an insulating coating for a 　grain- oriented electrical steel sheet according to an aspect of the present invention includes one or more hydrated silicate powders having an average particle diameter of 2 μm or less, and 　Σn i M i / .SIGMA.P i and one or more phosphoric acid and phosphate to satisfy the relation of ≦ 0.5, 　containing, 　satisfying the following (equation 1). 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Formula 1) (where P is the number of moles of phosphorus, M is the number of moles of metal ions derived from phosphate, n is the valence of metal ions derived from phosphate, and i is the number of types of phosphate , M'represents the number of moles of the metal element in the hydrous silicate, n'represents the valence of the metal element in the hydrous silicate, and j represents the number of types of the hydrous silicate.) <2> pieces According to another aspect of the invention, in the coating solution for forming the insulating coating for a grain-oriented electrical steel sheet according to <1>, the phosphate is Al phosphate, Mg phosphate, Ca phosphate. Any one of salt, Zn phosphate, and Ni phosphate may be used. <3> According to another aspect of the present invention, in the coating liquid for forming the insulating coating for a grain-oriented electrical steel sheet according to <1> or <2>, the hydrous silicate powder is kaolin powder. , Talc powder, and pyrophyllite powder. <4> A method of manufacturing a 　grain-oriented electrical steel sheet according to an aspect of the present invention is a method of applying a coating liquid for forming an insulating coating for grain-oriented electrical steel sheet to a grain-oriented electrical steel sheet after final finish annealing, In the step of performing a baking treatment, the coating liquid is a phosphoric acid satisfying the relationship of Σn i M i /ΣP i ≦0.5 with one or more hydrated silicate powders having an average particle size of 2 μm or less. And a phosphate, and one or more of them, which satisfies the following (formula 1), and has a step in which the baking temperature is 600°C to 1000°C. 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Formula 1) (where P is the number of moles of phosphorus, M is the number of moles of metal ions derived from phosphate, n is the valence of metal ions derived from phosphate, and i is the number of types of phosphate , M'represents the number of moles of the metal element in the hydrous silicate, n'represents the valence of the metal element in the hydrous silicate, and j represents the number of types of the hydrous silicate.) <5> According to another aspect of the present invention, in the method for producing a grain-oriented electrical steel sheet according to <4>, the phosphate is Al phosphate, Mg phosphate, Ca phosphate, or Zn phosphate. Either one of phosphate and Ni phosphate may be used. <6> According to another aspect of the present invention, in the method for producing a grain-oriented electrical steel sheet according to <4> or <5>, the hydrous silicate powder is kaolin powder, talc powder, and pyrophyllite. One or more light powders may be used. Effect of the invention [0016] 　Advantageous Effects of Invention According to the present invention, a grain-oriented electrical steel sheet having a large film tension, obtaining a film property excellent in space factor, corrosion resistance and water resistance, and having excellent iron loss, even without using a chromium compound. There is provided a coating solution for forming an insulating film, and a method for manufacturing a grain-oriented electrical steel sheet. Brief description of the drawings [0017] FIG. 1 is a cross-sectional photograph showing an example of a conventional grain-oriented electrical steel sheet having an insulating coating. FIG. 2 is a cross-sectional photograph of a grain-oriented electrical steel sheet having an insulating coating of Example 1. MODE FOR CARRYING OUT THE INVENTION [0018] 　Hereinafter, an example of a preferred embodiment of the present invention will be described. 　In the present specification, the numerical range represented by “to” means a range including the numerical values ​​before and after “to” as the lower limit value and the upper limit value. 　In the present specification, the term “process” is used not only as an independent process, but also in the case where the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. included. [0019] < 　Coating Liquid for Forming Insulating Coating for Grain-Oriented Electrical Steel Sheet > The coating liquid for forming the insulating coating for grain-oriented electrical steel plate (coating liquid for forming insulating coating) according to the present embodiment has an average particle diameter of 2 μm or less. 1 or 2 or more of the hydrous silicate powders of, and 1 or 2 or more of phosphoric acid and phosphate satisfying the relationship of Σn i M i /ΣP i ≦0.5. 　Then, P is the number of moles of phosphorus, M is the number of moles of metal ions derived from phosphate, n is the valence of metal ions derived from phosphate, i is the number of types of phosphate, and M′ is in hydrous silicate. The coating solution satisfies the following (formula 1), where n′ is the number of moles of the metal element, n′ is the valence of the metal element in the hydrous silicate, and j is the number of types of the hydrous silicate. 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Formula 1) When 　only phosphoric acid is selected, Σn i M i represents 0. [0020] 　Conventionally, for example, a hydrated silicate powder as a main component, the first phosphate salt (e.g., aluminum primary phosphate (Al 2 O 3 · 3-Way 2 O 5 · 6H 2 O)) was added and heated at 600 ° C. or higher The obtained insulating film can have a film tension equal to or higher than that of the insulating film obtained by baking a coating solution containing colloidal silica, primary phosphate and chromic acid. However, the inventors of the present invention have found that the grain-oriented electrical steel sheet produced in this manner has a poor space factor and a poor corrosion resistance and water resistance in some cases. [0021] 　Therefore, the inventors of the present invention examined the influence of the insulating coating of the grain-oriented electrical steel sheet on the space factor, corrosion resistance, and water resistance by making the following grain-oriented electrical steel sheets. 　To oriented electrical steel sheet having a thickness of 0.23mm completing the finish annealing, a coating solution having a composition comprising a first phosphate solution of colloidal silica aluminum phosphate, coating amount after baking 5 g / m 2 becomes As described above, it was dried and baked at 850° C. for 30 seconds. [0022] 　FIG. 1 is a cross-sectional SEM (scanning electron microscope) photograph of the film structure of the grain-oriented electrical steel sheet thus obtained. In FIG. 1, 11 is an insulating film and 13 is a finish annealing film (hereinafter, the reference numerals will be omitted and described). From this SEM photograph, it can be seen that many voids exist in the insulating film. The presence of these voids lowers the density of the insulating film and increases the film thickness for the same amount of film (g/m 2 ). As a result, the space factor is considered to be inferior. In addition, when a large number of voids are present, the voids may be connected to form a through hole in the insulating film. It is considered that the through holes allow moisture and moisture to pass therethrough, deteriorating the corrosion resistance of the electromagnetic steel sheet and also deteriorating the water resistance. [0023] 　From the observation of the cross-sectional SEM photograph of FIG. 1, the following can be estimated. When a mixture of hydrous silicate and primary phosphate is heated to 600° C. or higher, it is dehydrated to form anhydrous silicate and anhydrous phosphate. The anhydrous silicate maintains its original shape, and the anhydrous phosphate is incompletely bound between the particles of the anhydrous silicate. That is, incomplete fusion of silicate and phosphate causes void formation, which causes deterioration of space factor, corrosion resistance and water resistance. [0024] 　In order to eliminate the voids in the insulating film as observed in FIG. 1, it is conceivable to add an excessive amount of primary phosphate to the hydrous silicate. However, the addition of an excessive amount of primary phosphate increases the P 2 O 5 component that does not contribute to the film tension, and thus reduces the film tension obtained. Therefore, in order to eliminate or reduce the voids without lowering the film tension, it is desirable to reduce the voids while suppressing the addition amount of the phosphate component. 　Therefore, the present inventors studied to promote the reaction between silicate and phosphate to increase the fusion of the two. [0025] 　Phosphate is produced by reacting a metal oxide, a metal hydroxide or the like with phosphoric acid. Phosphates are classified according to the mixing ratio of phosphoric acid and metal oxides. When the number of moles of phosphorus in phosphoric acid or phosphate is P, the number of moles of metal ion in phosphate is M, and the valence of metal ion in phosphate is n, phosphoric acid and phosphate have nM/P= It is represented by 0, 1, 2, 3, etc. The value of nM/P is not limited to an integer value and can be continuously set between 0 and 3. The values ​​of n and M of phosphoric acid are zero. Therefore, nM/P=0 is phosphoric acid (H 3 PO 4 ). Also, nM/P=1, nM/P=2, and nM/P=3 are referred to as primary phosphate, secondary phosphate, and tertiary phosphate, respectively. [0026] 　Here, a specific chemical composition formula will be described by taking an aluminum salt of phosphoric acid as an example. The primary phosphate, secondary phosphate and tertiary phosphate are Al(H 2 PO 4 ) 3 , Al 2 (HPO 4 ) 3 and AlPO 4 , respectively. When nM/P>1, it becomes difficult for the phosphate to dissolve in water, and it becomes difficult to prepare a water-soluble insulating coating solution. It is considered that when a phosphate of nM/P<1 is used for the insulating film of the electromagnetic steel sheet, water-soluble P (phosphorus) remains in the insulating film after baking. Therefore, the phosphate generally used for the insulating film of the magnetic steel sheet has a composition of nM/P=1 represented by the primary phosphate. 　The present inventors believe that a phosphate and a phosphoric acid satisfying nM/P<1 which is not usually used for an insulating film of an electromagnetic steel sheet may improve the reactivity with a hydrous silicate. It was Further, the inventors of the present invention considered that the film characteristics would be improved by mixing a phosphate and phosphoric acid satisfying nM/P<1 and a hydrous silicate in an appropriate ratio. [0027] 　Then, when phosphoric acid of nM/P=0 and phosphate of 0 　Next, a method for manufacturing the grain-oriented electrical steel sheet according to the present embodiment will be described. [0048] 　The method for manufacturing a grain-oriented electrical steel sheet according to the present embodiment is, for the grain-oriented electrical steel sheet after final finish annealing, applying a coating liquid for forming an insulating coating for grain-oriented electrical steel sheet, and performing a baking process. Have. The coating liquid is one or more of hydrous silicate powders having an average particle size of 2 μm or less, and one or two of phosphoric acid and phosphate satisfying the relationship of Σn i M i /ΣP i ≦0.5. It is a coating liquid containing at least one kind and satisfying the following (formula 1). Further, the baking temperature is 600°C to 1000°C. [0049] 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Formula 1) 　However, P represents the number of moles of phosphorus. M represents the number of moles of metal ions derived from phosphate. n represents the valence of the metal ion derived from phosphate. i represents the number of kinds of phosphates. M'represents the number of moles of the metal element in the hydrous silicate. n'represents the valence of the metal element in the hydrous silicate. j represents the number of types of hydrous silicates. 　When only phosphoric acid is selected, Σn i M i represents 0. [0050] (Oriented Electrical Steel Sheet 　After Final Finish Annealing ) The grain oriented electrical steel sheet after final finish annealing is the direction in which it becomes the base material before the coating liquid (that is, the insulating coating film forming coating liquid according to the present embodiment) is applied. It is a magnetic electrical steel sheet. The grain-oriented electrical steel sheet after the final finish annealing is not particularly limited. As a suitable example, the grain-oriented electrical steel sheet used as a base material is obtained as follows. Specifically, for example, a steel slab containing 2% by mass to 4% by mass of Si is hot-rolled, hot-rolled sheet annealed, and cold-rolled, and then decarburized annealed. After that, an annealing separator having a MgO content of 50 mass% or more is applied, and final finish annealing is performed. The grain-oriented electrical steel sheet after the final finish annealing may not have the finish annealing film. [0051] (Application of Insulating Film Forming Coating Liquid and Baking Treatment) 　After applying the insulating film forming coating liquid according to the present embodiment to the grain-oriented electrical steel sheet after final finish annealing, baking treatment is performed. Although the coating amount is not particularly limited, it is excellent in film strength, space factor, corrosion resistance and water resistance, and further, in terms of obtaining an iron loss reducing effect, the amount of the film after forming the insulating film is 1 g/m 2. It is preferable to apply the coating solution in the range of 2 to 10 g/m 2 . More preferably, the amount of the coating after forming the insulating coating is 2 g/m 2 to 8 g/m 2 . The coating amount after the baking treatment can be obtained from the weight difference between the steel plates before and after the insulating film is peeled off by immersion in a 20% aqueous sodium hydroxide solution at 80°C. [0052] 　The method for applying the coating liquid for forming an insulating film to the grain-oriented electrical steel sheet after the final finish annealing is not particularly limited. For example, a coating method such as a roll method, a spray method, or a dip method may be used. [0053] 　After applying the coating liquid for forming an insulating film, baking is performed. In order to form a dense film and obtain good film tension, the reaction between the hydrous silicate powder and the phosphate (or the hydrous silicate powder and phosphoric acid) is promoted. Many hydrous silicates release structural water near a heating temperature of 550° C. and react with phosphate in the process. Therefore, the baking temperature is 600° C. or higher. On the other hand, when a baking temperature of more than 1000° C. is adopted, the grain-oriented electrical steel sheet is softened and easily distorted, so the baking temperature is set to 1000° C. or less. If the temperature is lower than 600°C, the reaction between the hydrous silicate powder and the phosphate is not sufficient. Therefore, each of the hydrous silicate powder and the phosphate is a mixed insulating film. The preferable lower limit of the baking temperature is 700° C. or higher, and the preferable upper limit is 950° C. or lower. The baking time is 5 seconds to 300 seconds, and more preferably 10 seconds to 120 seconds. [0054] 　The heating method for performing the baking treatment is not particularly limited, and examples thereof include a radiant furnace, a hot air stove, and induction heating. [0055] 　The insulating film after the baking process becomes a dense film. The thickness of the insulating film is preferably 0.5 μm to 5 μm, more preferably 1 μm to 4 μm. 　The thickness of the insulating film after the baking process can be obtained by observing the cross section SEM. [0056] 　Through the above steps, the coating liquid for forming an insulating film according to the present embodiment has a large film tension, obtains film properties excellent in space factor, corrosion resistance and water resistance, and has excellent iron loss, and a directional electromagnetic A steel plate is obtained. [0057] 　Although an example of the preferred embodiment of the present invention has been described above, it is obvious that the present invention is not limited to the above. It is obvious that the configurations of the above-described embodiments can be combined with each other, and that a combination of the configurations is also included in the technical scope of the present invention. The above is an exemplification, and any technology having substantially the same configuration as the technical idea described in the scope of the claims of the present invention and exhibiting the same operational effect is the technology of the present invention. It is included in the target range. Example [0058] 　Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. [0059] Example A 　First, a coating liquid having the composition shown in Table 1 is prepared. Next, a grain-oriented electrical steel sheet (B 8 =1.93T) having a sheet thickness of 0.23 mm and having a finish annealing film that has been subjected to final finish annealing is prepared. Next, the prepared grain-oriented electrical steel sheet was coated and dried with a coating solution having the composition shown in Table 1 so that the amount of the insulating coating after baking treatment would be 5 g/m 2, and the conditions were 850° C. and 30 seconds. Perform a baking process. 　With respect to the obtained grain-oriented electrical steel sheet with an insulating coating, the coating characteristics and magnetic characteristics are evaluated. The results are shown in Table 2. [0060] 　The average particle size of the hydrous silicate shown in Table 1 is a value calculated by the method described above. Further, the blending amounts of phosphoric acid and phosphate were adjusted so that the value of Σn i M i /ΣP i shown in Table 1 was obtained. For example, in Example 1, the phosphoric acid aqueous solution and the aluminum phosphate aqueous solution were mixed to adjust Σn i M i /ΣP i to 0.5. The compounding amount in Example 1 is the total value of the compounding amounts of solid anhydrous phosphoric acid and aluminum phosphate. 　(Σn i M i +Σn′ j M′ j )/ΣP i shown in Table 1 is a calculated value in which the hydrous silicate powder and phosphoric acid or phosphate are mixed and adjusted so as to have the values ​​shown in Table 1. .. 　Furthermore, the evaluation method of each evaluation shown in Table 2 is as follows. [0061] ( 　Space factor) Measured according to the method described in JIS C 2550-5 (2011) (correspondence: IEC 60404-13). [0062] (Corrosion resistance) A 　5 mass% NaCl aqueous solution is continuously sprayed on a test piece kept at 35° C., and the rust generation state after 48 hours has been observed to calculate the area ratio. [0063] (Water resistance) 　It is the amount of P (phosphorus) per unit area eluted by immersing a test piece (50 mm×50 mm ) in boiling water for 1 hour. The amount of P is a quantitative value analyzed by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy). [0064] (Film tension) The 　film tension is calculated from the warpage of the steel sheet that occurs when one surface of the insulating film is peeled off. The specific conditions are as follows. 　The insulating film on only one side of the magnetic steel sheet is removed with an alkaline aqueous solution. Then, the film tension is calculated from the warp of the electromagnetic steel sheet by the following (formula 2). 　　　Film tension=190×plate thickness (mm)×plate warp (mm)/{plate length (mm)} 2 [MPa]. ．．(Formula 2) [0065] (Iron 　Loss ) The iron loss is measured according to the method described in JIS C 2550-1 (2011) (correspondence: IEC 60404-2). Specifically, it is measured as the iron loss per unit mass (W 17/50 ) under the condition that the amplitude of the measured magnetic flux density is 1.7 T and the frequency is 50 Hz . [0066] [table 1] [0067] [Table 2] [0068] 　The composition of the reference coating liquid in Table 1 is as follows. 20% by weight colloidal silica aqueous dispersion: 100 parts by weight 50% aluminum phosphate aqueous solution: 60 parts by weight Chromic anhydride: 6 parts by weight [0069] 　The amounts of the clay mineral, phosphoric acid and phosphate added in Table 1 are calculated as anhydrides, for example, kaolin is calculated as Al 2 O 3 .2SiO 2 and aluminum monophosphate is calculated as Al 2 O 3 .3P 2 O 5. is there. [0070] 　As shown in Table 1, the insulating film of each example uses phosphoric acid and phosphate satisfying Σn i M i /ΣP i ≦0.5, and 1.5≦(Σn i M i +Σn′ j M′. j )/ΣP i ≦15, which is an insulating film formed using a coating liquid for forming an insulating film. Then, as shown in Table 2, the insulating coatings of the respective examples are not only large in coating tension and large in iron loss reducing effect, but also excellent in space factor, corrosion resistance and water resistance. Further, it can be seen that the insulating coatings of the respective examples can obtain the same or higher performance as the coating when the coating liquid containing the chromium compound shown in the reference example is used. [0071] 　On the other hand, in Comparative Examples 1, 2, 8, 13, and 14 in which Σn i M i /ΣP i exceeds 0.5, the porosity in the coating increases and the space factor and the corrosion resistance are inferior. Further, in Comparative Examples 3, 4, 11, and 14 　in which (Σn i M i +Σn′ j M′ j )/ΣP i exceeds 15, the porosity in the coating increases and the space factor and corrosion resistance are inferior. Is. 　Then, in Comparative Examples 5, 6, 10, and 13 in which (Σn i M i +Σn′ j M′ j )/ΣP i is less than 1.5, the water-soluble P in the film after baking increases and the water resistance increases. The film does not satisfy the property and the film tension is inferior. Since the film tension is also inferior, the iron loss is also inferior. 　Further, in Comparative Examples 7, 9 and 12 in which the average particle size of the hydrous silicate powder exceeds 2 μm, the reaction with phosphoric acid or phosphate is considered to be incomplete. Therefore, the number of voids in the coating after baking increases, the irregularities on the coating surface increase, and the space factor and corrosion resistance are inferior. [0072] 　Here, FIG. 2 shows a result of observing a cross section of the grain-oriented electrical steel sheet provided with the insulating coating of Example 1 by SEM. In FIG. 2, reference numeral 21 represents an insulating film, and 23 represents a finish annealing film (hereinafter, reference numerals will be omitted and described). As shown in FIG. 2, it was revealed that the insulating film of Example 1 was a dense film with very few voids. As shown in FIG. 2, since the insulating film of Example 1 is dense, it is considered that the insulating film is excellent in film tension, space factor, corrosion resistance and water resistance, and iron loss is improved. 　Therefore, the grain-oriented electrical steel sheet obtained by using the coating liquid for forming an insulating film of the present embodiment has a densified insulating film, and the film tension and the space factor are increased without using a chromium compound. It can be seen that the film has excellent corrosion resistance, water resistance, and iron loss. [0073] 　As described above, the conventional insulating film shown in FIG. 1 has many voids. Therefore, it is thicker than the insulating film of Example 1 shown in FIG. 2 although the coating amount after forming the film is the same 5 g/m 2 . It can be seen that the thickness of the insulating coating of Example 1 shown in FIG. 2 is about half the thickness of the conventional insulating coating shown in FIG. 1 due to the densification of the coating. [0074] (Example B) 　Next, the baking temperature is changed and the film characteristics and magnetic characteristics are evaluated. A coating solution having the same composition as that of Example 1 is applied and dried by the same procedure as that of Example 1 so that the amount of the insulating film after baking is 5 g/m 2 . Then, the baking temperature is changed to the conditions shown in Table 3 to perform the baking process (the baking time is 30 seconds). The results are shown in Table 3. [0075] [Table 3] [0076] 　As shown in Table 3, in Comparative Example 15 in which the baking temperature is less than 600° C., the space factor, the corrosion resistance, and the film tension are inferior because the reaction between the hydrous silicate powder and the phosphate is not sufficient. 　On the other hand, the respective examples in which the baking temperature is 600° C. or higher are excellent in the film characteristics and the magnetic characteristics. [0077] 　Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the idea described in the claims, and naturally, they also belong to the technical scope of the present invention. Understood. Industrial availability [0078] 　By using the coating liquid for forming an insulating coating for grain-oriented electrical steel sheet and the method for producing a grain-oriented electrical steel sheet according to the present invention, the coating tension is large even if a chromium compound is not used. It is industrially useful because it provides a grain-oriented electrical steel sheet having excellent film properties such as product ratio, corrosion resistance and water resistance, and excellent iron loss. The scope of the claims [Claim 1] 　And one or more of the following hydrated silicate powder having an average particle diameter of 2 [mu] m, 　.SIGMA.n i M i / .SIGMA.P i and one or more phosphoric acid and phosphate to satisfy the relation of ≦ 0.5, 　containing and, 　following coating solution for forming a grain oriented electrical steel sheet insulating coating that satisfies the equation (1). 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Formula 1) (where P is the number of moles of phosphorus, M is the number of moles of metal ions derived from phosphate, n is the valence of metal ions derived from phosphate, and i is the number of types of phosphate , M'represents the number of moles of the metal element in the hydrous silicate, n'represents the valence of the metal element in the hydrous silicate, and j represents the number of types of the hydrous silicate.) [Claim 2] 　2. The orientation according to claim 1, wherein the phosphate is any one of Al phosphate, Mg phosphate, Ca phosphate, Zn phosphate, and Ni phosphate. A coating liquid for forming an insulating film for magnetic steel sheets. [Claim 3] 　The grain-oriented electrical steel sheet according to claim 1 or 2, wherein the hydrous silicate powder is one or more of kaolin powder, talc powder, and pyrophyllite powder. A coating liquid for forming an insulating film. [Claim 4] 　A step of applying a coating solution for forming an insulating coating for a grain-oriented electrical steel sheet to a grain-oriented electrical steel sheet after final finish annealing and performing a baking treatment, wherein the coating fluid has an average particle size of 2 μm or less. Containing one or more kinds of hydrous silicate powder and one or more kinds of phosphoric acid and phosphate satisfying the relationship of Σn i M i /ΣP i ≦0.5, the following (formula 1) A method for producing a grain-oriented electrical steel sheet, which comprises a coating liquid satisfying the above conditions, and having a step in which the temperature of the baking treatment is 600° C. to 1000° C. 　　　1.5≦(Σn i M i +Σn′ j M′ j )/ΣP i ≦15. ．．(Equation 1) (where P is the number of moles of phosphorus, M is the number of moles of metal ions derived from phosphate, n is the valence of metal ions derived from phosphate, and i is the number of types of phosphate). , M'represents the number of moles of the metal element in the hydrous silicate, n'represents the valence of the metal element in the hydrous silicate, and j represents the number of types of the hydrous silicate.) [Claim 5] 　The directional electromagnetic field according to claim 4, wherein the phosphate is any one of Al phosphate, Mg phosphate, Ca phosphate, Zn phosphate, and Ni phosphate. Steel plate manufacturing method. [Claim 6] 　The grain-oriented electrical steel sheet according to claim 4 or 5, wherein the hydrous silicate powder is one or more of kaolin powder, talc powder, and pyrophyllite powder. Method.