JPS6043426B2 - Glazing inhibitor and its usage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When melt-plating composite metals such as zinc, aluminum, aluminum-zinc alloy, tin, and tin-lead alloy onto one side of a steel plate, the present invention provides a method for melt-plating metals such as zinc, aluminum, aluminum-zinc alloy, tin, and tin-lead alloy onto one side of a steel plate. The present invention relates to an anti-plating agent for preventing metal adhesion and a method of using the anti-plating agent.

Generally, when producing a single-sided hot-dip galvanized steel plate, a galvanizing agent is applied to one side of the steel plate, and the steel plate coated with the galvanizing agent on one side is immersed in a hot galvanizing solution. Single-sided hot-dip galvanized steel sheets are manufactured by attaching molten metal to the steel sheet surface other than the steel plate surface coated with the galvanic metal. Various methods have been proposed.

For example, a plating inhibitor made of water glass was proposed in Japanese Patent Publication No. 39-711, and a plating inhibitor made of a phosphate solution was proposed in Japanese Patent Publication No. 42-24966. As a result of various studies, the present inventors have confirmed that although these anti-plating agents have a considerable anti-plating effect, they have the following problems.

In other words, the anti-glaze agent made of water glass is: (1) Because the concentration is high or the coating is uneven, if it is applied thickly to enhance the anti-glazing effect, the anti-glazing agent may be applied to the molten coating bath. During the drying process before immersing the coated steel plate, a phenomenon of ``foaming'' occurs in the plating inhibitor, and as a result, the steel plate coated with the glazing inhibitor is immersed in a hot melting bath. As a result, "a physical plating metal adhesion phenomenon is observed in the foam part. (2) Because a dense glassy coating layer is formed by the heat applied during the drying process and the process of passing through the molten plating bath, this coating layer is It has drawbacks such as being extremely difficult to remove, and plating inhibitors made of phosphate solutions (1) contain many thermally unstable compounds;
Therefore, it is easily decomposed thermally (2) After being applied to the non-plated surface of the copper plate, the coating layer is changed in its traveling direction by a roll such as a deflector roll during the drying process and melting process of melting. It was confirmed that there are many unstable factors such as damage and the coating layer peeling off from the damaged area and adhesion of plated metal.

The present inventors have found, based on the problems encountered in the production of single-sided hot-dip galvanized steel sheets, that a plating inhibitor is required to have the following properties in order to eliminate the above-mentioned drawbacks.

That is, (1) the adhesion of plating metal can be completely prevented; and (2) the coating layer formed by the plating inhibitor is thermally stable and stable in a non-oxidizing atmosphere. (
3) During the process in which the plating inhibitor is applied to the non-plated surface of the steel plate and transferred from the drying process to the melting bath, the coating layer formed on the non-plated surface of the steel plate may be damaged or peeled off. (4) It is an essential requirement for a plating inhibitor that the coating layer formed with the plating inhibitor can be easily removed after melting and plating. I came to the conclusion that.

In other words, a stagnant inhibitor that satisfies the above requirements is
These requirements are extremely effective when manufacturing single-sided hot-dip galvanized steel sheets, and the necessity of these requirements will be explained in detail by briefly introducing the current status of galvanizing equipment. Explain in detail. In the process before being immersed in a hot-dip plating bath, the plating inhibitor needs to be applied to the non-plating surface of the steel plate. It must be applied to the non-plating surface immediately before being introduced.

On the other hand, in the Sendzimer method and other gas cleaning methods in a heated atmosphere, the anti-plating agent must be applied to the non-plated surface of the steel sheet immediately before it is introduced into a series of successive furnaces. In this way, the plating inhibitor must be applied to the non-plated surface of the steel sheet, but in the case of the flux method, the steel sheet is heated in a "flux drying oven" at a temperature of 200 to 450°C as a process after the plating inhibitor is applied. Since the plating inhibitor is introduced into the melting bath after the melting process, the thermal conditions that the plating inhibitor is exposed to are not very high, so it is not a big problem. However, in the case of the Sendzimer method, the The steel plate is first oxidized and preheated in a high temperature atmosphere of 1000 to 130 degrees, and then the steel plate temperature is 75 degrees.
Since it is exposed to a high-temperature reducing atmosphere at a temperature of 0 to 900°C, the plating inhibitor needs to withstand high-temperature oxidizing and reducing atmospheres. Therefore, when the plating inhibitor is thermally decomposed and reduced in the Sendzimer method melt plating, the atmosphere in the furnace becomes unstable, which may cause defects on the plated surface. This causes a phenomenon in which the plated metal adheres to the non-plated surface. Also,
In either plating method, the steel plate coated with the plating inhibitor passes through various support rolls, deflector rolls, and pinch rolls before being introduced into the melting bath. Since the coating layer formed with the sticking inhibitor is subjected to frictional stress and bending stress due to contact with the roll, mechanical strength that can withstand these stresses is also required. This is because if the coating layer formed with the plating inhibitor does not have the mechanical strength to withstand these stresses, the coating layer formed with the plating inhibitor will be damaged, and the damaged area will peel off. This is because plating metal may adhere to the parts. Furthermore, the copper plate that has undergone the hot-dip plating bath does not require a coating layer formed with a plating inhibitor after plating, so it must be easily removable. In other words, if the coating layer formed with the plating inhibitor reacts with the five surfaces of the steel sheet under the above-mentioned heating furnace conditions, or if a glassy film of the plating inhibitor is formed on the steel sheet surface, the coating layer formed with the plating inhibitor may be removed. This makes it extremely difficult to obtain a beautiful steel plate surface. The present inventors have intensively investigated drugs that can be used as eyelid inhibitors under the above-mentioned restricted conditions, and found that Al2
One or more selected from O3, SlO2, MgO, TiO2, BeO, etc. and/or a composite thereof and/or these together with K2O, Na2O, CaO, Ll2
A metal oxide whose main component is a compound with O, in which an unavoidable component is mixed, and which is almost insoluble in water and thermally stable, with an average particle size of 0.01μ to 1. By using a liquid made by mixing and suspending a fine powder substance of .5 microns in water as a medium as a sticking inhibitor, the second coating layer formed by this sticking inhibitor can prevent sticking. We have found that it is not only effective but also thermally stable, has mechanical strength, and has extremely good removability after nailing.

Hereinafter, the plating inhibitor and method of using the same according to the present invention will be explained in detail based on two examples in the case of hot-dip galvanizing. Table 1 shows the main ingredients of the chemicals used in the plating inhibitor, their chemical formulas, the properties of the main ingredients at room temperature and when mixed with water, and the effect of preventing adhesion of molten zinc as a result of using them. , Melt! Reactivity with dipped zinc, mechanical strength of the coating layer formed with the plating inhibitor (hereinafter sometimes referred to as the plating inhibitor coating layer), and removal of the plating inhibitor coating layer after the coating layer This table shows the results of judgment from the following viewpoints.

In addition, the results of this Table 1. The results are the results when hot-dip galvanizing was carried out on one side using the dry flux method, and 50 to 60 g of galvanizing inhibitor was applied in a wet state to the non-galvanized surface of the steel plate.
350-4 after spray painting to a coating amount of /d.
After drying in a drying oven at 00°C for 60 to 80 minutes to form a coating layer of a galvanizing agent on the non-plated surface, the steel plate is immersed in a hot-dip galvanizing bath for 1.0 to 1 j seconds. There is a result.
The properties of the plating inhibitor coating layer were judged based on the following criteria. )
Molten zinc adhesion prevention effect (observation of zinc adhesion state on the non-plated surface of the steel plate after the steel plate has passed through the molten galvanizing bath)
◎・・・・・・Zinc is not attached at all 0・・・・・・
・Zinc is slightly attached Δ... Zinc is partially attached ×... The amount of zinc attached is quite large) Reactivity with molten zinc (W4 plate is Observation of the presence or absence of smoke generation when passing through the molten plating bath and color change of the plating inhibitor coating layer before and after passing through the molten plating bath)◎・・・・・・
・There is almost no change in color tone of the anti-plating agent coating layer before and after passing through the melting bath. Changing Δ...When the anti-plating agent coating layer passes through the melting bath, a little smoke is generated and the coating layer melts.
There is a noticeable change in color tone before and after passing through the bath.
After the plating inhibitor coating layer passes through the molten melting bath, it becomes a heterogeneous film.
Observation of the coating layer after the coating layer passes through the melting bath)◎・・・・・・The coating layer of the coating inhibitor does not peel or crack before and after passing through the melting bath. shape
0, which is in almost perfect condition as it was made...
・The plating inhibitor coating layer has some defects before and after the melting bath, but it is not so large that it causes any practical problems. There was some peeling before and after passing through the melting bath, and a small amount of zinc was attached to some areas after passing through the hot-melting bath.
...The plating inhibitor coating layer was considerably damaged before and after passing through the hot-dip bath, and there was a lot of zinc adhesion.4) Removal of the galvanizing agent coating layer after plating (steel plate after passing through the hot-dip bath) (Observation of difficulty in removing the anti-glare coating layer when light brushing combined with washing with water) ...The anti-glaze coating layer remains slightly. The coating layer of the anti-glazing agent remains considerably. The coating layer cannot be removed. In Table 1, experiment no. 1 to 4 are comparative examples, and NOl is a stagnation inhibitor using a phosphoric acid aqueous solution;
Experimental sitting. 2 to 4 are cases where water glass and a silicate aqueous solution were used as anti-stagnation agents, respectively, and experimental brown. 5
~21 contains the plating inhibitor according to the present invention. This is an example in which SiO2, Al2O3, MgO, TlO
2. One or more selected from BeO and/or a composite thereof and/or K2O, Na2O
, Ll.

A metal oxide whose main component is a compound with O, which is almost soluble in water and thermally stable, with an average particle size of 0.01 μm or more.
This is a case in which a suspension of a powder substance in the range of 1.5 μm in water as a medium is mixed and suspended in an amount of 3% by volume. As is clear from Table 1, in the comparative example, experiment No. l
The anti-glaze agent using phosphate has a considerably effective anti-plating effect and removability of the coating layer of the anti-plating agent after plating, and in this respect, it has relatively good reactivity with molten zinc and Because the strength of the adhesion inhibitor coating layer is slightly inferior, the properties are inferior in terms of zinc adhesion, and experimental failures, 2 to 4
All anti-stacking agents using silicate containing water glass are solutions that are easily soluble in water and have a considerable anti-stick effect, but if the solution adheres to a thick layer and dries, it will cause physical damage. Zinc adhesion was observed due to the removal of zinc, and since the drying properties were poor, it was confirmed that even if normal drying was performed after application, zinc adhesion occurred due to foaming in areas where the solution was thought to have adhered. Ta.

In addition, experiment No. The water-soluble silicates of 2 to 4 showed no zinc adhesion in the thin film, and the mechanical strength was good as a glassy transparent film was formed, but this glassy film was dense. Since it is a strong film and is insoluble in water, it is extremely difficult to remove after plating, so even if a thin film is immersed in a molten plating bath and no foaming occurs and zinc adhesion can be completely prevented, plating will be completed. It is extremely difficult to remove the plating inhibitor coating layer from the non-plated surface of the steel plate afterwards, and it is not practical. On the other hand, experimental sitting. 5 to 21 relate to Examples of the plating inhibitor according to the present invention, and Experiment No. 5, 6, l7, l8. and 19, the main components are alumina, silica sand powder, magnesium oxide, titanium oxide,
and a single component of beryllium oxide, Experiment No. 7
-13 and 20 have kaolin as the main component (Al2O3.2
Si02・2H20) Talc (3Mg0-.4Si0-
H2O), potassium aluminosilicate (Al2O3・K2
O.6Si02), potassium aluminosilicate (Al.
O3・CaO-6SI02), sodium aluminosilicate (
．． Al2O3●Na2O●6Si02), lithium aluminosilicate (Al2O-3Be0●6S102), beryllium aluminosilicate (AI2O-3Be0●6S10)
2), is made of a composite material such as titanite (TiO2●CaO●SlO2), and is used as an experimental seat. 14, the main component is alumina 8
and 2 parts of titanium oxide. l
Experiment No. 5 is mainly composed of a mixture of 2 parts of silica sand powder and 8 parts of kaolin, that is, a mixture of 1 type of metal oxide and 1 type of composite. The main components of 16 were a mixture of 1 part of silica sand powder, 8 parts of kaolin, and 1 part of lithium aluminosilicate, that is, a mixture of 1 metal oxide and 2 composites; No. 21 consists of a mixture of 6 parts of alumina, 2 parts of titanium oxide, 1 part of beryllium oxide, and 1 part of magnesium oxide, and contains the above-mentioned agents, namely SlO2, A
One or more of l2O3, MgO, TlO2, BeO and/or a composite thereof and/or these and K2,
A powder substance, which is a metal oxide whose main component is a composite of Na2O, CaO, and Li2O, is almost soluble in water, and has a thermally stable average particle size of 0.01p to 1.5μ is added to water. 3
These anti-plating agents are used as anti-plating agents by mixing them in such a manner that the amount of saliva is % It can be seen that both the mechanical strength of the plating inhibitor coating layer and the removability of the plating inhibitor coating layer after plating are excellent. In other words, when these anti-plating agents according to the present invention are used, the effect of preventing adhesion of molten zinc is completely suppressed, and the effect of preventing the adhesion of molten zinc is slightly reduced when using anti-plating agents using silicates or phosphates. No adhesion was observed, there was no reaction with molten zinc, and there was no foaming phenomenon that was observed with silicate aqueous solutions.The coated layer of anti-stick powder that was formed after coating and drying remained as it was after plating. It was confirmed that the product passed through the hot-dip galvanizing bath without any change.

Furthermore, since the anti-glazing agent coating layer is a laminated film of powder, this anti-glazing agent coating layer is rolled during the process of applying the O-plating inhibitor, drying, and melting in the melting bath. There was a concern that the anti-plating agent coating layer on the non-plating side of the steel plate after passing through the hot melting bath was almost intact and passed through with little damage. I was also able to confirm that. In addition, the removal of the plating inhibitor coating layer after plating is hardly affected by the thermal conditions of passing through a drying oven or melting bath, so these plating inhibitor coating layers cannot be washed with water. It was also confirmed that it could be easily dispersed in water and removed by simple Bratsung used in combination. As is clear from the above evaluation results of the characteristics of the plating inhibitor coating layer, the plating inhibitor according to the present invention has a higher plating inhibiting effect than the comparative phosphates and water-soluble silicates. It can be said to be an excellent anti-flag agent because it has excellent properties such as reactivity with molten zinc, mechanical strength of the anti-flag coating layer, and removability of the coating layer after plating.

In addition, in the comparative examples of sodium silicate and potassium silicate, the anti-plating agent foamed after passing through the molten melting bath, and physical zinc adhesion was observed in this area, but these were mixed with water and became a suspension. It is thought that the silicate and water form and dissolve in a hydrated state, and for this reason, during drying after application, the silicate and water are quickly separated and dehydrated, and the silicate enters the melting bath without being fully dehydrated. It is thought that foaming occurs due to rapid heating, albeit for a short period of time. The plating inhibitor according to the present invention hardly forms hydrates due to the use of metal oxide powder that hardly dissolves in water. After applying the plating inhibitor to the plating surface, it can be quickly dried in the drying process, and as a result, when the steel plate is immersed in the hot-dip plating bath, there is no reaction between undehydrated water and molten zinc. be.

This is one of the conditions when using the plating inhibitor according to the present invention in which a suspension of a powder substance is used as the plating inhibitor, that the non-plating surface of the steel plate and the plating inhibitor are dried after being applied. This can be said to confirm that the requirements can be satisfied without any problems and advantageously. The above explanation is about the use of various plating inhibitors in hot dip galvanizing, but the plating inhibitor according to the present invention is aluminum,
It can be similarly used for hot-dip plating of aluminum-zinc alloys, tin, tin-lead alloys, etc. FIG. 1 is a quantitative view of the stability of various metal oxides at high temperatures, and is a diagram showing the relationship between the standard energy of formation (Δ6) and temperature. In FIG. 1, it can be said that the smaller the absolute value of the negative value of the standard production energy ΔG, the greater the stability of the oxide of this element. In other words, this curve shows that oxides of magnesium, aluminum, titanium, silicon, etc. are highly thermally stable compared to oxides of iron and copper. Of these, oxides such as potassium and sodium are inferior to the highly stable oxides mentioned above at high temperatures, and calcium oxides are highly thermally stable, but these oxides are Since it cannot be used alone as a plating inhibitor because it reacts and decomposes when mixed and suspended as a medium, Al. O3・K2
Composites such as O.6Si02 and Al2O.Na2O-6Si02 can be used because they have a high melting point of about 140 (s) and good thermal stability. Also, L
i2O and BeO are not shown in Figure 1, and the melting point of lithium oxide is 1700°C and that of beryllium oxide is 25°C.
The very high temperature of 72C indicates that the thermal stability is good. Furthermore, in Fig. 1, FeO and cO2O have slightly inferior thermal stability compared to the above-mentioned oxides, which is not good, but at the same time, in a reducing atmosphere at high temperature, FeO
, CL]20 can be converted to FeO by the reactions of the following equations 1 and 2.
These oxides have no effect as plating inhibitors in a high-temperature reducing atmosphere, as oxidants become Fe and cu2O becomes Cu.
It is no longer possible to completely prevent the adhesion of plating metal. That is, for example, FeO maintains an equilibrium state of equation 1 at a temperature of 773°C, which is the partial pressure ratio of hydrogen and water vapor in the atmosphere, and the hydrogen partial pressure equation beyond this value changes to the right of equation 1 as the temperature increases. The reaction to the direction progresses.

Note that the metal oxide used in the plating inhibitor according to the present invention exists stably as a metal oxide under the reduction conditions of the iron oxide present on the surface of the steel sheet in normal hot-dipping equipment. Therefore, the effect as an anti-glare agent is not impaired. As stated above, the main component of the drug used in the anti-plating agent of the present invention is Sl.
One or more selected from O2, Al2O3, MgO, TiO2, BeO and/or a composite thereof and/or K2O, Na2O, Ca3, Li2O
It is a metal oxide whose main component is a composite of metal oxide, which is almost insoluble in water and is a thermally stable powder.This powder is mixed and suspended in water as a medium to be used as a plating inhibitor. They discovered that by using it as an anti-plating agent, it has excellent effects not found in conventional anti-plating agents. In addition, the drugs used in the anti-stagnation agents shown as examples of the present invention in Table 1 have an average particle size of 0.01μ to 1.5μ, which is extremely fine. The more the anti-glare agent is kept in suspension, the easier it is to use.

That is, the following three equations are relational equations expressing the falling velocity of particles suspended in a liquid due to gravity, and are generally known as Stokes' law. Where ■: Falling speed of particles due to gravity in liquid g: Gravitational velocity σ: Specific gravity of the substance that makes up the particles d: Particle diameter η: Liquid viscosity coefficient From these three equations, the falling speed is determined by the particle size. Since it is proportional to the square of the square, it can be seen that the larger the diameter of the particles and the greater the specific gravity of the particles, the faster the falling speed, and the smaller the viscosity coefficient of the medium liquid, the faster the falling speed.

Figure 2 is a trial calculation of the falling speed due to gravity when water is used as the medium in the above three equations, where I is when the specific gravity is 2.7, and ■ is when the specific gravity is In the case of 3.1, ■ is the case where the specific gravity is 5.3. From FIG. 2, it can be seen that when the particles are ultrafine powders with a particle size of 0.01 μm, the falling speed due to gravity is very slow, and as a result, a very stable suspension can be maintained. Furthermore, when the particle size of the particles becomes 1 μ, when the specific gravity of the particles is 2.7, it is 6 to 7 Tnm/Hrl, and when the specific gravity of the particles is 5, it is 10
Particles fall and settle at a rate of ~12 Tn/Hr. As the particles settle in this manner, it can be predicted that the water and particles will be completely separated. Also, the particle diameter is 1
When it becomes 0μ, the sedimentation rate of particles with a specific gravity in the range of 2.7 to 3.1 becomes ~45c7x/Hr, and it can be seen that the separation phenomenon becomes clear even by visual measurement. In general, chemicals used in anti-glare agents contain some impurities, so it can be predicted that the calculations shown in Figure 2 will not be the same, but the trend is that the above-mentioned phenomenon will occur. .

The present inventors observed silica sand powder with an average particle size of 0.015 p, 0.8
A painted plate in which a 2% suspension of μ kaolin powder, 1.5 μ alumina powder, 3 μ alumina powder, etc. was prepared using water as a medium, and then the prepared solution was immediately sprayed onto the copper plate surface. A comparison was made between the coated surface of the steel plate and a painted plate in which the supernatant liquid of the suspension was left to stand for 6 minutes after adjustment and was spray-coated onto the steel plate surface.

As a result, there was a significant difference in the finish of the painted surface of a suspension of alumina powder with a particle diameter of 3μ between those applied immediately after the suspension was prepared and those applied 6 times after the preparation. The supernatant liquid of the suspension after the filtration process was extremely thin, so the painted surface was coated with a liquid that was close to water. In addition, if the diameter of the particles is 1.5μ, after adjusting the suspension
It was confirmed that even the supernatant liquid after rinsing was slightly thinner than the suspension immediately after preparation, and there were no major problems in practical use.
It should be noted that there was almost no difference between the coated plates using suspensions of silica sand powder and carrion powder, both immediately after preparation and after 6 minutes of preparation. In other words, if the average particle size of the particles is 1.5μ or less, the stability of the suspension is good, and it is possible to maintain a stable painted surface with no uneven coating on the painted surface, and at the same time, it is possible to maintain a stable coating surface with no unevenness on the painted surface. It can be seen that because it is dispersed as particles in the state, it is possible to prevent the particles from settling due to gravity when applying the souffle, and there is almost no clogging in the souffle piping or nozzle clogging. If the anti-glaze agent has these characteristics, it will almost never separate the water and the particles in the paint tray in which the anti-glaze agent is placed when it is applied to the surface of the steel plate using a roll coater. Since it can be applied to the steel plate surface without causing any damage, it is possible to uniformly apply the amount of the anti-plating agent.Also, if the average particle size of the agent is less than 0.01μ, as will be confirmed next, Therefore, when using a thermally stable commercially available agent such as the one mentioned above, it is necessary to measure it with a microscope or other means, filter it as necessary, or use a wet ball mill. Grind to a predetermined particle size with an average particle size of 0.01μ to 1.5μ
Use the one.

Next, the metal oxide powder substance (drug) used as the plating inhibitor in the present invention has an average particle size of 0.01 μm as described above.
It has an effect as an industrially practicable plating inhibitor when the particle size is in the range of ~1.5μ, and the metal oxide has an average particle size outside the above range, or the metal oxide has an average particle size outside the above range. Table 2 shows the results of an experiment which confirmed that a mixture of the above metal oxides containing some of the above metal oxides is unsuitable as a plating inhibitor.

The experimental method and the items and criteria for each characteristic of the coating layer are exactly the same as those in Table 1. As can be seen from Table 2,
Even if the metal oxide used in the plating inhibitor is a mixture, good results are obtained when the average particle size of all the metal oxides is 0.01μ to 1.5μ (Experiment No. 22, 23). .

However, if the average particle size exceeds 1.5μ (
In Experimental Teams 24 to 35), when the steel plates passed through the plating bath, the mechanical strength of the plating inhibitor coating layer decreased and peeled off, causing zinc to adhere or damage. Moreover, when the average particle size was less than 0.01 μm (experimental brown. 36 to 45), the removability of the plating inhibitor coating layer was decreased. This is because if the average particle size of the metal oxide powder material is too small, the metal oxide will enter the recesses on the surface of the copper plate when it is removed by blanching and washing with water. In addition, the average particle size of some metal oxides in the metal oxide mixture is within the specified range (0.01μ
-1.5μ) (experimental samples 46 to 50), the influence of the average particle size outside the respective specified ranges appears, and good results cannot be obtained. Furthermore, the coating amount of the plating inhibitor coating layer formed by applying the plating inhibitor according to the present invention to the non-plated surface of the steel plate and drying it, the greater the coating amount, the better the plating inhibiting effect. However, since the formed coating layer is a laminated film of powder, the thicker the film, the more easily it peels off and becomes a brittle film.

Therefore, the average particle size of the particles on the non-plated surface of the steel plate is 1.5.
A stagnation inhibitor using μ alumina powder is uniformly sprayed so that the coated layer after drying has a predetermined amount in the range of 1 to 70 g/d, dried in a drying oven, and then melted. The relationship between the frictional stress and bending stress received by each roll passing through while being immersed in the soaking bath was investigated in relation to the plating prevention effect. As a result, as shown in Table 3, the coating amount range after drying is 3 to 50 g to achieve a complete plating prevention effect without peeling or cracking of the plating inhibitor coating layer.
It turned out to be /i. In other words, if the coating amount of the plating inhibitor after drying is less than 3 g/d, there is almost no abnormality in the plating inhibitor coating layer, but because the coating layer is thin, plating metal adhesion occurs partially. , the effect of preventing the adhesion of plated metal on the non-plated surface is insufficient, and if the amount of coated plated metal after drying exceeds 50 g/d, the coated layer of plated metal is a laminated film of powder. It is observed that the coating layer is somewhat weak against frictional stress and bending stress, which is thought to be caused by this, and the coating layer peels off from the non-plated surface of the steel plate in some parts, and the plated metal adheres to the peeled off part. was recognized.

As detailed above, the plating inhibitor according to the present invention is
One or more selected from O2, Al2O3, MgO, TiO2, BeO and/or these together with K2O, N
Mixing and suspending in water a fine powder substance, which is a metal oxide mainly composed of a composite of a2O, CaO, and Li2O, with unavoidable components mixed therein, and has an average particle size of 0.01μ to 1.5μ. By applying such a plating inhibitor to the non-plated surface of the steel plate, it is possible to completely prevent molten galvanic metal from adhering to the non-plated surface of the steel plate, and also prevent plating. There is no reaction between the coating agent and the hot-dip galvanizing metal, the mechanical strength of the coating layer formed with the galvanizing agent is excellent, and the non-plating surface of the steel sheet after being led out to the hot-dip galvanizing bath. It is an innovative anti-plating agent that has all the necessary properties for industrially producing single-sided hot-dip galvanized steel sheets, such as the fact that it is extremely easy to remove the unnecessary anti-plating agent coating layer attached to the surface. .

Also, in terms of use, the average particle size is 0.01μ to 1.5μ.
By using a suspension of extremely fine metal oxide powder of 5 μm mixed and suspended in water as a medium, the suspended state of the powder particles can be constantly maintained, and the non-stick properties of the steel plate can be maintained. In the coating process, which forms a plating inhibitor coating layer on the plated surface, it is possible to prevent nozzle clogging during spray application and pipe clogging due to powder settling in the spray pipe, and to prevent powder clogging in the saucer during roll coater application. By preventing dilution of the plating inhibitor due to sedimentation, problems in application management can be solved. Furthermore, it has been found that the properties of the above-mentioned plating inhibitor can be made even more excellent by using the coated layer after coating and drying the plating inhibitor in a range of 3 to 50 g/d. Note that when a steel plate is melt-welded on one side using the plating inhibitor according to the present invention, the adhesion of the plating metal can be completely prevented on the non-plated surface by the plating inhibitor coating layer, but the plating bath Due to thermal conditions such as heating the steel plate in a plating bath or heating the plated surface after passing through a plating bath, the non-plated surface may be oxidized through the plating inhibitor coating layer and oxides may be generated. As mentioned above, this oxide is removed in advance by simple brushing with washing with water, and then in the next step, it is mixed with an oxide film removal solution, for example, in the case of single-sided molten lead plating, in a phosphoric acid aqueous solution. With a solution in which one or more selected from zinc phosphate and phosphates of metals with a higher ionization tendency than zinc are mixed into the liquid and the pH is adjusted to a range of 1.5 to 3.5. By removing it by dipping or spraying, it is possible to produce a beautiful single-sided plated steel sheet with no oxide film on the non-plated surface.

As described above, the plating inhibitor and method of using the same according to the present invention relate to an excellent plating inhibitor having properties not found in conventional plating inhibitors and an effective method of using this plating inhibitor. It has become possible to manufacture plated steel strips cheaply and easily, and its industrial value is extremely large.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the standard energy of formation of various metal oxides and temperature, and Figure 2 shows the relationship between the falling speed due to gravity and the particle diameter of particles with different specific gravity when water is used as a medium. FIG. 1... Particles with a specific gravity of 2.7, ■... Particles with a specific gravity of 3.1, ■... Particles with a specific gravity of 5.0.

Claims (1)

[Claims] 1 SiO_2, Al_2O_3, MgO, TiO_2
, one or more selected from BeO and/or a composite thereof and/or K_2O, Na_2
It is a metal oxide whose main component is a composite of O, CaO, and Li_2O, with other unavoidable components mixed in.It hardly melts in water and is thermally stable, with an average particle size of 0.01μ. ~
A plating inhibitor used for producing a single-sided hot-dip galvanized steel sheet, characterized in that a fine powder substance of 1.5 μm is mixed and suspended in water as a medium. 2 SiO_2, Al_2O_3, MgO, TiO_2
, one or more selected from BeO and/or a composite thereof and/or K_2O, Na_2
A metal oxide whose main component is a composite of O, CaO, and Li_2O, with unavoidable components mixed in, and which is almost insoluble in water and thermally stable, with an average particle size of 0.01 μm or more.
After drying, the coating amount of the anti-plating agent, which is a fine powder substance of 1.5μ mixed and suspended in water as a medium, is 3.
A method for using a plating inhibitor, which comprises applying it to a non-plated surface of a steel plate so that the amount is ~50 g/m^2. 3. The method of using a plating inhibitor according to claim 2, which comprises applying the plating inhibitor by spray coating. 4. The method of using a plating inhibitor according to claim 2, wherein the plating inhibitor is applied by roll coater coating.