KR20100029638A - Liquid surface conditioner - Google Patents

Abstract

PURPOSE: A liquid surface conditioner is provided to prevent flying dust and to enable use of a fixed quantity at a time by keeping the liquefied state. CONSTITUTION: A liquid surface conditioner is produced by mixing water 64~88wt.% with fine solid powder 22~36wt.%. The solid powder contains sodium compound 2.3~6.5wt.%, polyphosphate 5~15wt.%, titanium compound 1~3wt.%, and potassium(K) compound 2.0~7.3wt.%. The potassium compound can control potassium stain in a phosphate coating agent below 550ppm and prevent solidification in winter time.

Description

Liquid surface conditioner {LIQUID SURFACE CONDITIONER}

The present invention relates to an improvement of a surface modifier for neutralizing or activating a metal surface before applying a phosphate coating to a metal material.

In general, phosphate coating is one of the widely used methods for pretreatment of metals, and chemically treating the metal surface to form a high adhesion and stability compound film on the surface. It is well known in the art that the phosphate coating treatment is an essential requirement to increase the physical properties of the coating, ie, adhesion, durability, corrosion resistance, and flex resistance, in the subsequent metal coating process, and before the phosphate coating treatment, the metal surface is neutralized or Most of the surface adjustment treatment using the surface conditioner is performed for activation.

Therefore, the coating of metals such as iron or zinc material is performed by degreasing → washing → surface adjustment → phosphate coating → washing → drying → coating (electrodeposition).

In the pretreatment of metal coating, the purpose of the surface adjustment treatment performed before the phosphate coating is listed in more detail as follows.

-Perform surface adjustment to make the crystal of phosphate film dense and fine.

-Perform surface adjustment to shorten the film formation time.

-Improving the texture of paint by suppressing the occurrence of iron phosphate coating, which is a blue color, by adjusting the surface.

-Perform surface adjustment to equalize the inactive areas (welding or stressful areas) and the active parts of the steel plate surface.

-Stabilize the surface of the steel sheet in acid oxidized water vapor layer before entering the film forming process.

-After pickling, neutralize the acid remaining on the surface of steel sheet.

Existing surface modifiers used in the surface adjustment treatment to be carried out for the above purpose is to commercialize the titanium compound in the form of a powder mixed with pyrophosphate or phosphate and then pulverized after high temperature drying.

However, if you use the conventional surface conditioner in the form of powder, the working environment is bad due to scattering dust, and due to its properties, it hardens when it meets water. Therefore, it is not directly added to the process. shall. In addition, there is a disadvantage in that it is difficult to automate because the powder form is not easy to dose.

In addition, the conventional powder surface regulator has a problem that the surface adjustment is not properly made when the metal material is black corrugated sheet to cause hindrance to the phosphate coating, and there was also a problem that does not function properly in hard water of more than 250mg / L total hardness.

Therefore, it is an object of the present invention to provide a liquid surface conditioner to implement a liquid surface conditioner, but even in winter, there is no problem in the function and when the metal material is black corrugated sheet and exhibits its function even in hard water of more than 250mg / L hardness.

In order to achieve the above object, the present invention provides a liquid surface conditioner by mixing 64 to 88% by weight of water as a solvent and 22 to 36% by weight of solids pulverized into fine particles. Potassium contamination is controlled to 550 ppm or less in the phosphate coating together with 2.3 to 6.5% by weight of the compound, 5 to 15% by weight of the polyphosphate, and 1 to 3% by weight of the titanium compound, and 2.0 to 7.3% by weight of the potassium (K) compound to prevent solidification in the winter. It is characterized by including the composition.

In addition, the present invention, a water-soluble organic solvent is 64 to 88% by weight of the solvent and the fine powder pulverized 22 to 36% by weight of the mixture to obtain a liquid surface control agent, the solid content of 22 to 36% by weight sodium compounds 2.3 to 6.5 Along with the weight percent, polyphosphate 5-15 wt% and titanium compound 1-3 wt%, the phosphate coating is controlled to less than 550 ppm of potassium contamination and contains 2.0 to 7.3 wt% of potassium (K) compound to prevent solidification in winter. It is characterized by.

The present invention maintains its function even when the powder surface conditioner is liquefied, and since the liquid surface conditioner can be maintained even when stored indoors in the winter, the dust does not fly and the work environment is improved and the liquid form. It is easy to quantitatively, which contributes to automation, and even if the metal material is black skin plate, surface adjustment is properly performed, and it has the advantage of properly functioning even in hard water of over 250mg / L of total hardness.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The inventors have attempted to liquefy existing powder surface modifiers.

Conventional surface modifiers used in the present invention as a compound containing titanium in the phosphate and pyrophosphoric acid or polyphosphoric acid, water and titanium sulfate, dibasic sodium phosphate, sodium pyrophosphate, sodium carbonate, It is a product made by mixing with caustic sodium, sodium bicarbonate, etc., and heating and drying it at 100 ~ 120 ℃ (hereinafter referred to as powder surface conditioner).

However, attempts to liquefy existing powder surface modifiers had the following difficulties.

First, as a result of dispersing water with a solvent using finely dispersed 0.1 ~ 1% by weight of a conventional powder surface conditioner, the surface adjustment function was lost in a short time (8 days) as shown in the comparison picture in FIG. . Figure 1 (a) is a photographic picture of the phosphate coating immediately after 5g / ℓ after liquefaction, Figure 1 (b) is a photographic view of the phosphate coating after 5g / ℓ after 8 days liquefaction.

Second, as shown in the photograph (a) (b) (c) of FIG. 2, the liquefaction was not intact due to the solidification (crystallization) of phosphate in the indoor storage in winter. Immediately after production, there was no problem as shown in (a) of FIG. 2, but as the solidification of phosphate proceeds as storage in winter, layer separation occurs as shown in FIG. 2 (b), and as in FIG. 2 (c) later. Precipitation of crystals is caused.

The present inventors have sufficiently studied the cause of the loss of the surface adjustment function in a short period of time of the liquefaction attempts, the results were obtained as follows.

One of the causes of the loss of surface control function is that titanium pyrophosphate is converted to titanium hydroxide or titanium oxide by water and alkali, which are solvents, as shown in Scheme 1 below. .

In addition, various metal ions (Ca, Mg, Fe, etc.) in water used as a solvent are combined with sulfates in the powder surface conditioner, and it is considered that the surface adjustment function of the effective titanium colloid (Ti-colloid) is significantly reduced.

Therefore, in the present invention, polyphosphate or chelate was used to minimize various obstacles and side effects in water as solvents, and the best results were obtained when 10 ± 5% by weight of polyphosphate was used. . The chelating agents include E.D.T.A, NTA, 3Na, D.T.P.A, 5Na, Sodium Glyconate, and the like.

Instead of water, a water-soluble organic solvent, that is, a glycol-based solvent such as amine solvents such as triethanol amine (TEA) and diethylamine, and ethylene glycol (Ethylene Glycol) As a result of using alcohols such as glycerin and glycerin as a solvent, it was confirmed that it has surface adjustment ability for 1 to 2 years after commercialization. However, when the water-soluble organic solvent is used, the manufacturing cost is high, and there is a disadvantage that the working environment is slightly worsened due to the peculiar smell such as ammonia during use.

Another cause of the loss of surface adjustment function of the difficulty of the liquefaction attempt of the present invention was confirmed in Table 1 through the experiment that the sharp drop in pH.

5 g / ℓ pH Dry bath 9.6 Day 2 9.4 Date 9.2 Day 4 9.0 Day 5 8.8 Day 6 8.6 Day 7 8.4 Day 8 8.2

As shown in Table 1, after 8 days of drying the liquid surface conditioner, pH decreases to 8.2, and side effects such as thickening of the coated particles due to coarsening of titanium colloid (Ti-colloid) begin to occur. . Liquid surface adjusting agent in to contact with thus is not stable with the water than the powder surface conditioner phosphate material and titanium colloid (Ti-colloid) of carbon dioxide (CO ₂₎ in the I air The phosphate material at the same time as geonyok to particle contact It is assumed that the oxidation reaction as in Scheme 2 takes place.

Accordingly, the inventors of the present invention obtained good results as a result of appropriately prescribing triphosphate and a pH stabilizer to prevent oxidation of phosphate. An example of the triphosphate is sodium triphosphate, and an example of the pH stabilizer is sodium triphosphate and borax.

On the other hand, the present inventors analyzed the cause of the solidification (crystallization) of the phosphate in winter, and the solution to solve it could be obtained through experiments.

As an example of the conventional powder surface modifier, the composition of the powder surface modifier disclosed in Japanese Patent Publication No. 39-7125 (1983.12.8) includes titanium sulfate 5%, anhydrous dibasic sodium phosphate 55%, anhydrous sodium pyrophosphate 15%, 15% water, 10% sodium bicarbonate and the like are powdered, and existing surface conditioners on the market are close to the composition ratio. To this, a pH stabilizer, an oxidative stabilizer, a modulator lasting agent and the like are further added.

Solubility of water as a main component in the conventional powder surface modifier as described above is shown in Table 2 below.

Substance Solubility (10 ℃) Dibasic sodium phosphate (Na2HPO ₄ 12H ₂ O) 3.48 Sodium Pyrophosphate (Na ₄ P ₂ O _{7 ·} 10H ₂ O) 3.65 Trisodium Phosphate (Na ₃ PO ₄ ) 5.11

Therefore, in order to function as a surface modifier, 20 to 35% of the powder surface modifier must be dispersed or dissolved in a solvent (water) to achieve the purpose. Since the sodium phosphate compound exceeds the solubility of water, phosphate precipitation occurs.

In order to improve this, the present inventors used sodium phosphate together with potassium phosphate having a relatively higher solubility in water than the sodium phosphate.

Solubility of potassium phosphate is shown in Table 3 below.

Substance Solubility (0 ℃) Dipotassium Potassium Phosphate (K ₂ HPO _{4 ·} 3H ₂ O 57.3 Potassium Pyrophosphate (K ₄ P ₂ O _{7 ・} 3.5H ₂ O) 65.7 Potassium Triphosphate (K ₃ PO _{4 ·} 7H ₂ O) 44.2

 As shown in Table 3 above, the potassium phosphate used in the present invention is 10 to 20 times higher in solubility than sodium phosphate. Therefore, the substitution of potassium phosphate instead of sodium phosphate prevented the precipitation of phosphate in winter.

However, if there is a process line in which the potassium ion content in the coating agent can be controlled to 500 ppm or less, there is no problem even if the potassium phosphate is present in the liquid surface conditioner. However, depending on the process line, it contains a large amount of liquid surfacing solution through the surface adjustment section, and when it is added to the filming zone, the next process, the potassium content gradually increases, and when it reaches 550 ppm, it becomes an iron film. Cause paint failure. Therefore, it is necessary to appropriately adjust the content of potassium phosphate.

In the present invention, by solving the problem as described above, the powder surface conditioner was implemented as a liquid surface conditioner, and according to the characteristics of ① surface contamination due to scattering dust in the conventional powder surface conditioner, ② do not directly put into the process due to the nature of the powder surface conditioner. It was not possible to coagulate (dissolve and not dissolve), and it was possible to solve the trouble of dissolving and inputting in a separate dissolution tank.

In addition, in the present invention, if the conventional powder surface modifier is ③ hard water (total hardness of 250 or more) or ④ the material is black skin (Fe ₃ O ₄ ) surface adjustment is not properly caused problems to the phosphate film hard water softener and metal complex salt This was solved by using an appropriate agent. As the water softener and the metal complex salt, poly phosphate and a chelating agent were used. The chelating agent includes EDTA, NTA 3Na, DTPA, 5Na, Sodium Glyconate.

In the embodiment of the present invention, the solvent used in the liquefaction is water (H ₂ O), amine (Amine) solvent such as TEA, glycol (Glycol) solvent such as ethylene glycol (Ethylene Glycol), glycerin (Glycerine) Alcohol-based solvent.

In an embodiment of the present invention, a titanium colloidal phosphate (Ti-colloid) was used for the surface adjustment function. Phosphate of titanium colloid was pulverized into fine particles of powder obtained through the mixing reaction of titanium sulfate, second, third sodium phosphate, and second, third potassium phosphate and dissolved or dispersed in a solvent. % By weight was used.

In addition, in the embodiment of the present invention, potassium-based phosphate and compounds (hereinafter referred to as 'potassium (K) compounds)' were used for the diffusion of the liquid surface conditioner function. The potassium (K) compound includes second and third potassium phosphates, potassium bicarbonate, potassium carbonate, and potassium hydroxide (KOH). However, excessive use of potassium (K) compound increased the amount of potassium in the phosphate coating liquid and caused the phosphate coating to be disturbed when it was over 550 ppm, so that the potassium (K) compound was contained at 2 to 7.3 wt%.

Based on the above description, the effective examples of the present inventors experimented are shown in Table 4 below.

Item [% by weight] Example 1 Example 2 Example 3 Example 4 Example 5 Dibasic Sodium Phosphate 6.0 3.7 1.8 3.7 1.8 Trisodium Phosphate 0.5 - 0.5 - 0.5 Dibasic Potassium Phosphate 1.0 - 2.5 - 2.5 Tripotassium Phosphate 1.0 0.5 2.5 0.5 2.5 Titanium sulfate 1.0 2.0 3.0 2.0 3.0 Sodium bicarbonate 0.1 0.1 0.1 0.1 0.1 Potassium bicarbonate 0.1 0.1 0.1 0.1 0.1 Polyphosphate 5.0 10.0 15.0 10.0 15.0 Pyrophosphate 0.5 1.3 5.0 1.3 5.0 Potassium carbonate 0.1 0.2 0.2 0.2 0.2 borax 3.0 4.0 2.0 4.0 2.0 Potassium Hydroxide (KOH) 1.0 2.0 2.0 2.0 2.0 Chelating agents 2.0 0.7 1.0 0.7 1.0 Dispersant 0.1 0.1 - - - Sedimentation inhibitors 1.0 1.0 - - - Water (H ₂ O) Residual Residual Residual - - Water Soluble Organic Solvent - - - Residual Residual system 100 100 100 100 100

In Table 4, as the dispersant, poly octyl, poly ethylen, nonyl phenyl ether, and the like are used, and antisettling agents include polyvinyl alcohol and CMC. And hydroxyethyl cellulose.

The analysis of the components of the embodiments described in Table 4 by series is shown in Table 5 below.

Component [wt%] Example 1 Example 2 Example 3 Example 4 Example 5 Solid content 22 25 36 - - Sodium compounds 6.5 3.7 2.3 3.7 2.3 Potassium (K) Compound 3.2 2.0 7.3 3.8 7.3 Pyrophosphate 0.5 1.3 5.0 1.3 5.0 Polyphosphate 5.0 10.0 15.0 10.0 15.0 borax 3.0 4.0 2.0 4.0 2.0 Titanium compound 1.0 2.0 3.0 2.0 3.0

In Table 5, since the solids account for 22 to 36% by weight as the remaining components excluding the solvent, that is, water or a water-soluble organic solvent, the remaining solvent accounts for 64 to 88% by weight. From 22 to 36% by weight solid, sodium compounds 2.3 to 6.5% by weight, polyphosphate 5 to 15% by weight, potassium (K) compound 2.0 to 7.3% by weight, titanium compound 1 to 3% by weight and the like.

Table 6 shows the results of testing the above embodiments with various test items.

Item Example 1 Example 2 Example 3 Example 4 Example 5 Remarks One Refrigerated storage test (4 ℃ 15 days)  clear  clear  clear  clear  clear Winter comparison test of liquid gradation 2 Immediate bath temperature (5g / ℓ) 9.5 9.6 10.3 9.5 10.5 Liquid 3 pH stability (after 8 days) SEM SEM SEM SEM SEM Liquid 4 CR steel sheet SEM Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ After Phosphate Coating 5 CR steel sheet c / w (g / m ² ) 2.8 2.5 2.3 2.5 2.1 After Phosphate Coating 6 EG steel SEM 2 ~ 5㎛ 2 ~ 5㎛ 2 ~ 5㎛ 2 ~ 5㎛ 2 ~ 5㎛ After Phosphate Coating 7 EG steel sheet c / w (g / m ² ) 2.8 2.5 2.5 2.5 4.5 After Phosphate Coating 8 Black corrugated sheet c / w (g / m ² ) 2.7 2.6 2.2 2.6 2.2 After Phosphate Coating 9 Salt spray corrosion resistance after electrodeposition coating of CR steel More than 800 hours More than 800 hours More than 800 hours More than 800 hours More than 800 hours After Phosphate Coating 10 Salt Spray Corrosion Resistance after Electrodeposition of Black Steel Plates More than 400 hours More than 400 hours More than 400 hours More than 400 hours More than 400 hours After Phosphate Coating 11 Flexural resistance after electrodeposition coating of CR steel clear clear clear clear clear 10mm diameter round bar 12 Flexural resistance after electrodeposition coating of EG steel clear clear clear clear clear 10mm diameter round bar 13 Impact resistance after electrodeposition coating of CR steel clear clear clear clear clear 14 Impact resistance after electrodeposition coating of EG steel clear clear clear clear clear 15 SEM after hard water use Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ Spherical 2 ~ 5㎛ 250ppm total hardness 16 Cw (CR steel plate) g / m ² 2.8 2.6 2.4 2.6 2.3 250ppm total hardness

As can be seen in Table 6 above, the liquid surface conditioner of the present invention solves the problems or disadvantages of the conventional powder surface conditioner while fully performing its function as a surface conditioner.

In FIG. 3, the photograph of the zinc phosphate film (b) after the surface adjustment with the liquid surface conditioner according to the embodiment of the present invention is omitted, and the photograph of the zinc phosphate film (a) is omitted without surface adjustment. As can be seen in FIG. 3 (b), the zinc phosphate coating after surface adjustment showed excellent coating properties (corrosion resistance, flex resistance, environmental resistance) after electrodeposition coating.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

The present invention can be used for pretreatment for metallic coatings.

1 is a photographic result of dispersing (liquidifying) water into a solvent using a conventional powder surface conditioner, (a) is a phosphate coating degree after 5 g / l dry bath immediately after liquefaction, and (b) after 8 days of liquefaction Figure of phosphate coating after bathing.

2 is a view showing the solidification of phosphate (crystallization) during storage in winter after liquefying water to a conventional powder surface conditioner with a solvent.

3 is a view showing a zinc phosphate-coated photograph (b) after the surface adjustment with a liquid surface conditioner according to an embodiment of the present invention and a photograph of the zinc phosphate-coated photograph (a) without the surface adjustment.

Claims (3)

64 to 88% by weight of water is used as a solvent and 22 to 36% by weight of solids pulverized into fine particles are mixed to obtain a liquid surface conditioner. In the 22 to 36% by weight of solids, 2.3 to 6.5% by weight of sodium compound and 5 to 5% of polyphosphate 15% by weight, 1 ~ 3% by weight of titanium compound, the phosphate coating is controlled to less than 550ppm of potassium contamination, and it is composed of 2.0 ~ 7.3% by weight of potassium (K) compound to prevent solidification in winter. . 64 to 88% by weight of a water-soluble organic solvent as a solvent and 22 to 36% by weight of solids pulverized into fine particles are mixed to obtain a liquid surface control agent, the solid content of 22 to 36% by weight of sodium compounds 2.3 to 6.5% by weight, polyphosphate 5 ~ 15% by weight, 1 ~ 3% by weight of titanium compound, the phosphate coating is controlled to less than 550ppm of potassium contamination, and it is composed of 2.0 ~ 7.3% by weight of potassium (K) compound to prevent solidification in winter. Surface conditioner. According to claim 2, wherein the water-soluble organic solvent is triethanol amine (Triethanol Amine) (TEA), diamine (Amine) -based solvent including diethylamine (Dietly Amine), glycol containing ethylene glycol (Ethylene Glycol) (Glycol A liquid surface modifier, characterized in that the solvent is an alcohol-based solvent containing a) solvent, glycerin (Glycerine).

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