JPH03174481A - Acid-resistant guard wax - Google Patents

Abstract

PURPOSE:To provide an acid-resistant guard wax excellent in the function for protecting a coating from acid rain and good in workability in coating by dispersing a specific amount of an acid-neutralizing agent in a wax base material. CONSTITUTION:0.5-20wt.% acid-neutralizing agent is dispersed in a wax base material to produce an acid-resistant guard wax. As specific examples of the acid-neutralizing agent, an alkalin agent such as sodium hydrogencarbonate, sodium carbonate and sodium stearate, or buffering agent which has a buffer action on an acid, such as potassium dihydrogenphosphote and disodium hydrogenphosphate can be mentioned. Occurrence of color change, crack, blotch, etc., of coatings by acid rain can be effectively prevented by applying the obtained acid-resistant guard wax to a coating of a car produced at a factory for protection until the car is delivered to a customer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an acid-resistant guard wax that is applied to coatings on automobiles, etc.

(Prior Art) Automobiles produced at a factory may be pooled in a finished car pool within the factory, for example, until they are delivered to a customer. In such cases, guard wax is applied to the car to protect the paint film from rain and iron particles in the air.

The conventionally used guard wax is a polyethylene wax with trace amounts of antioxidants and ultraviolet absorbers added, and has an organic coating of around 10 μm that has a certain degree of guarding ability against acidic liquids.

The component composition of the conventionally used guard wax is shown in Clothing 1 below.

(Problem to be Solved by the Invention) However, the above-mentioned conventional guard wax has poor guarding properties against acidic liquids, and despite the application of such conventional guard wax, recent acid rain has caused finished cars to pool in pools. Many cars in the field are damaged by the acid rain, which penetrates the guard wax film and hydrolyzes and contaminates the paint film, causing discoloration and cracking.
Or, situations such as stains and water spots have occurred.

In view of the above circumstances, an object of the present invention is to provide a guard wax that has strong acid resistance even if it is a thin film.

(Means for Solving the Problems) In order to achieve the above object, the acid-resistant guard wax according to the present invention has an acid neutralizing agent in the wax base material of 0.5 to 20%.
It is characterized in that it is added and dispersed in an amount of 0% by weight (based on the entire guard wax).

As the acid neutralizer, an alkaline agent that neutralizes the acid or a buffer agent that has at least a buffering effect against the acid can be used.

As the alkali agent, for example, NaHCO3 (sodium hydrogen carbonate), Na2CO1 (sodium carbonate), or C17H3, COONa (sodium stearate) can be suitably used.

In particular, C1tH35COONa is an alkaline agent that dissolves only in warm water, and is preferably used in combination with an alkaline agent that dissolves in water at room temperature, such as NaHCO3.

As the above-mentioned buffer, for example, a buffer value obtained by mixing KH2PO, (potassium dihydrogen phosphate) and Na2HP 04 (disodium hydrogen phosphate) has a pH of 667 to 8.
．． 0 can be suitably used.

In particular, the above KH2PO4 and Na2HPO4 were mixed at 4:6.
A buffer having a combined buffer value of (KH2PO4/Na2HPOa-4/6) p) 18.98 can be suitably used.

Both the alkaline agent and the buffer are powders, and those having a particle size of 1 to 10 μm are preferably used.

(Function) The acid-resistant guard wax with the above structure has an acid neutralizer (an alkaline agent that neutralizes acids or a buffer that has a buffering effect against acids) added and dispersed in the guard wax, which attacks the paint film. They neutralize (including buffering) acidic solutions that
and becomes harmless.

In addition, since the acid neutralizer is added and dispersed in the above guard wax in an amount of 0.5 to 20% by weight, it does not deteriorate the workability of applying the guard wax, etc., as shown from the experimental data described below. It has sufficient guarding properties even against highly acidic liquids with a pH of about 2, and can sufficiently protect paint films from acid rain, etc.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

When using Na2CO3 as an acid neutralizer, the inventors
0.0% of sodium carbonate (Na z CO3), which is one of the acid neutralizers mentioned above, is added to the conventional guard wax described above.
Four types of guard waxes were prepared by adding and dispersing OJ and 0.5.20% by weight (% by weight based on the entire wax containing Na2CO3), and experiments were conducted using them to confirm the acid resistance effect.

The experimental results are shown in Table 2.

In the acid resistance effect test of the guard waxes, as shown in Table 2 above, guard waxes with the above-mentioned Na2CO3 addition amounts of 0%, 0.3%, 0.5%, and 20% were used. Guard wax film thickness is 5μ and 10μ
In the case of rabbits, acidic solutions of pH 2, 3, and 4 were applied to the rabbits, respectively, and the state of the coating films was examined.

In addition, each of the above experiments was conducted at a temperature of 30°C using a gradient oven.
The temperature was between ℃ and 80℃, and the heating time was 2 hours.
The adhesion amount of the acidic liquid was set to o, tcc.

Note that the guard wax should be used in a range of 5 μm to 10 μm, considering its protection against not only acid rain but also other things (for example, iron powder resistance).
Since rabbit is set as the standard film thickness to be used, film thicknesses of 5μ and 10μ were set as test targets in order to conduct tests at the upper and lower limits.

In addition, for the reasons explained below, the added Na2CO3 should have a particle size smaller than 5μm when the film thickness is 5μm, and a particle size smaller than 10μm when the film thickness is 10μm. Using.

Generally, the acid resistance effect depends on the film thickness of the guard wax.

Varies depending on acid concentration, temperature, etc. Therefore, under more severe conditions, i.e., the film thickness is 5 μm, which is the lower limit of the above standard usage range, the temperature is 80°C, and the acid concentration is at pH 2 because the concentrated state of acid rain is approximately pH 2. in,
It can be said that it can withstand use as an acid-resistant guard wax if no irreparable staining occurs on the coating film.

Examining the results in Table 2 above from this perspective, it is found that Na2C
If the O3 content is 0.5% or more, everything is OK (no irreparable contamination on the paint film), and therefore Na2CO3
It is recognized that if it contains 0.5% or more, it can withstand use as an acid-resistant guard wax. In addition, the temperature listed under NG in Table 2 means that irreparable staining occurred on the coating film within that temperature range.

Figure 1 shows that the film thickness of guard wax in the above experiment was 5.
This is a diagram showing the relationship between the contamination state of the paint film and the surface temperature of the paint film when the pH of the acidic solution is 2 and the content of Na2CO3 is 0%, 0.5%, and 20%. From the figure, N
It is recognized that if the content of a2CO3 is 0.5% or more, it can be sufficiently used as an acid-resistant guard wax. Note that Δ (stain, waterside) in FIG. 1 disappears when left or heated, and since this stain can be repaired, it does not impair its practical value as an acid-resistant guard wax.

On the other hand, the above-mentioned NazCO3 is a powder, and if too much of it is added, the viscosity of the guard wax increases, the coating workability deteriorates, and it becomes difficult to form a uniform guard wax film.

Figure 2 is a diagram showing the relationship between the amount of Na2CO3 added (% by weight relative to the entire wax containing Na2CO3) and viscosity.As can be seen from this figure, as the amount of NaHCO3 added increases, the viscosity also increases. When the amount added exceeds 20%, it falls into the shaded region where coating workability deteriorates (difficult to form a uniform guard wax film). Therefore, the above Na2CO3
From the viewpoint of coating workability, the amount added must be 20% or less.

Next, the size of the NazCO3 powder to be added will be described.

The particle size of the Na2CO3 powder to be added is preferably equal to or less than the thickness of the guard wax film. Therefore, when the film thickness is set to 5 μm to 10 μm as described above,
The particle size is preferably at most 5 μm to 10 μm depending on the film thickness.

As shown in FIG. 3, when the particle size of the NazCO3 powder that is the acid neutralizer 6 is larger than the thickness of the guard wax film 4 on the coating film 2, the guard wax film 4 is cut by the NazCO3 powder. The acid enters from there, and pinhole-like contamination occurs in the coating film 2. Moreover, if the particle size is large, the coating gun may become clogged or dispersion becomes poor.

On the other hand, when the particle size of the s Na z C03 powder 6 is smaller than the thickness of the guard wax film 4, the state shown in FIG. A Japanese additive layer is formed, and coating workability is also good. There is no particular lower limit to the particle size, or it is preferably 1 μm or more in view of ease of handling.

Cases in which something other than NazCO3 is used as an acid neutralizer The above example uses Na2CO3 powder as an acid neutralizer, but even if it is the above-mentioned NaHCO3 powder, or a buffer K is
Even if it is a mixture of M2PO, powder and Na2HPO4 powder, or even other acid neutralizing agents, the acid resistance effect will be the same as shown in Table 2 and Figure 1 above, and the coating workability will be as shown in Figure 2. The particle size is, of course, the same as that of Na2CO3 powder. Therefore, the acid neutralizer that can be used in the present invention is not limited to Na2CO3 powder, and the amount added should be 0.5 to 20% by weight. It is desirable that the particle size is smaller than the thickness of the guard wax film.

In addition, when using a buffer as an acid neutralizer, considering the acid resistance and the effect on the paint film, KH2P as mentioned above should be used.
A mixture of O4 and Na2HPO with a buffer value in the range of 6.7 to 8.0 can be preferably used.

As an acid neutralizer, an alkaline agent such as NaHCO3 and C. The above-mentioned Na2CO3 and NaHCOs may be added and dispersed alone, or may be added and dispersed together with another suitable alkali agent. is C I7H3
It can be added and dispersed together with 5COONa (sodium stearate).

The above-mentioned NazCO3 and NaHCO3 have the property of being eluted in water at room temperature, and as a result, when it rains, they are eluted from the wax base material into the rainwater and have a neutralizing effect on the acids in the rainwater. Therefore,
Although it is very suitable as a neutralizing agent against acid rain, on the other hand, after being exposed to a certain amount of rain, most of it is eluted from the wax base material, and the wax has no acid-resistant effect.

It will become.

However, the above C+7HisCOONa does not dissolve in water at room temperature, but only in hot water (dissolves 10% by weight in hot water of 100"C, begins to dissolve at around 60°C and becomes saturated at 100°C).
It is something to do. Therefore, this CI7H35COONa
When added to the wax base material, the C+tI(s
, cOONa does not elute in normal rainwater (normal temperature rainwater during rain), but when the rainwater that remains on the paint film after the rain stops and becomes concentrated due to the temperature rise due to solar heat, it elutes into the rainwater and dissolves in acid. Demonstrates a harmonious effect.

Therefore, if an alkaline agent such as the above Na2CO3 that dissolves in water at room temperature and the above CI7H35COONa are added and dispersed together in a wax base material, Na2CO3 etc. will be effective against normal rainwater, but will be effective against residual rainwater. is C+7H3,
COONa exhibits an acid neutralizing effect and can improve the acid resistance effect of the wax as a whole.
3. COONa does not dissolve in normal rainwater, so it remains in the wax base material for a relatively long period of time. Therefore, the acid resistance effect of the wax as a whole is compared to the case of using only an alkaline agent such as Na2CO3 that dissolves in water at room temperature. It can be maintained for a long time.

When using an alkaline agent such as the above-mentioned NB2CO3 which dissolves in water at room temperature and Cl7H35C00Na, it is preferable to add and disperse each of them into the wax base material in the proportions shown in Table 3 below. Note that all the values in Table 3 below indicate weight % based on the total wax.

Table 3 Table 4 below shows the results of a test to confirm the acid resistance effect of guard wax when 2.0 and 3.0% by weight of C1□H3sCOONa was added to the entire wax. In addition, in this test, the film thickness of the guard wax was 10μ, and the particle size of sodium stearate was 1(]μ.
Other test conditions were the same as those in Table 2.

Table 4 Acid resistance effect of guard wax ○: No contamination △: Repairable contamination As seen from Table 4 above, CI7H3SCOONa is 2
．． When added in amounts of 0 and 3.0% by weight, sufficient acid resistance effects are exhibited. Therefore, when C1□H3 and COONa are used together, it is sufficient to add C17H3 and cooNa within the range that can ensure the acid resistance effect, and the amount of addition is not too large, resulting in a decrease in coating workability due to increased viscosity. , is preferably used in combination as shown in Table 3 above.

In addition, when C1□H3sCOONa and a buffer are used together,
The acid neutralizing effect of CI7H35COONa is buffered by a buffer. Therefore, CI7H3SCOONa can be used in combination with an alkaline agent, but it is meaningless to use it in combination with a buffer.

(Effects of the Invention) As explained above, since the acid-resistant guard wax according to the present invention is made by adding and dispersing an acid neutralizer in an amount of 0.5 to 20% by weight, the workability of applying the guard wax may be deteriorated. It is possible to sufficiently protect the paint film from acid rain.

[Brief explanation of the drawing]

Figure 1 shows the contamination state of the paint film when the amount of acid neutralizer added and temperature are changed. Figure 2 shows the relationship between the amount of acid neutralizer added and the viscosity of guard wax. Figures 3 and 4 are cross-sectional views of the guard wax film portion. 4...Guard Wax 6...Acid Neutralizer Diagram Z Footprint ('C) Diagram 2 0 +5 2゜5 *1at 1% of NG2CO3)

Claims (1)

[Claims] An acid-resistant guard wax characterized in that an acid neutralizer is added and dispersed in a wax base material in an amount of 0.5 to 20.0% by weight.