JPS63158246A - Low glossy coated steel plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to low-gloss coated steel sheets, and the present invention provides coating properties such as scratch resistance, hardness, adhesion, weather resistance, etc., by particularly modifying coating-forming components. The aim is not only to improve the glossiness but also to advantageously reduce the glossiness.

(Prior art) In general, methods for reducing the gloss of the paint film on low-gloss coated steel sheets include increasing the pigment concentration in the paint, adding a large amount of filler, and even adding a small amount of silicic acid anhydride. Methods such as adding a matting agent such as powder are known. However, all of these methods have the drawback that the viscosity of the paint increases and the fluidity deteriorates, resulting in a decrease in paint film performance such as processability, weather resistance, and adhesion as well as painting workability.

Therefore, various attempts have been made to solve the above problems. For example, JP-A-57-3867 proposes a method of adding a resin and mica-like iron oxide (MIO), and JP-A-60-40172 proposes a method of adding various inorganic powders.

(Problems to be Solved by the Invention) However, with the above method, although it was possible to improve one or two of the characteristics required depending on the purpose, it was not possible to satisfy all of the characteristics. I didn't get anything.

For example, the former method disclosed in JP-A-57-3867 not only provides insufficient hardness but also fails to provide a satisfactory low gloss. On the other hand, the latter method disclosed in JP-A No. 60-40172, although low gloss can be obtained, has drawbacks such as the coating film becoming too hard and damaging the roll during molding, and furthermore, painting workability is poor. A solution to this problem was strongly desired.

The present invention advantageously satisfies the above-mentioned requirements, and is a low-gloss coating that has a surface gloss level of 10% or less, and has coating properties such as high hardness, good scratch resistance, weather resistance, and processability. The purpose is to propose steel plates.

(Means for Solving the Problems) Now, the inventors have solved the problems of the prior art as described above (as a result of intensive research, baking is a hardening type film as a film forming component). Through trial and error, they discovered that the intended purpose could be advantageously achieved by using a mixture of the main forming elements and specific inorganic powders or resin powders as a vehicle, leading to the completion of this invention. It is.

That is, the present invention includes, as film-forming components, 100 parts by weight of a main film-forming element that is cured by baking, and 5 parts by weight of at least one selected from nepheline syenite powder, polyacrylonitrile resin powder, and potassium titanate fiber. ~50 parts by weight, 21 to 5 parts by weight of silicic anhydride, and mica: 5 to 5 parts by weight.
This is a low-gloss coated steel sheet made by coating and baking a vehicle containing 0 parts by weight on the surface of a base steel sheet.

This invention will be explained in detail below.

The main elements of the baking used in this invention to form a hardening film include oil-based or water-based fests.
Any material that is commonly used in the field of paints may be used, including fests such as natural oils or processed oils, alkyd resins, phenolic resins, polyester resins, epoxy resins, epoxy ester resins, amino alkyd resins, and acrylics. Paints such as resins, vinyl chloride resins, silicone-modified acrylic resins, silicone-modified polyester resins and fluororesins are advantageously suitable.

In this invention, the various inorganic powders and hardened resin powders listed above are added to 100 parts by weight (hereinafter simply referred to as parts) of the main film-forming elements as described above, and the amounts of these additions are The reason for limiting to the above range will be explained.

Nepheline syenite powder, polyacrylonitrile resin powder and/or potassium titanate fiber: 5 to 50 parts If the amount of these is less than 5 parts, the effect of reducing gloss and improving scratch resistance will be poor; If the amount exceeds 1 part, the processability deteriorates, so the amount of these components is limited to 5 to 50 parts, preferably 7 to 35 parts, whether added alone or in combination.

In addition, nepheline syenite powder is Na-K-Al□5izO
It is a fine white powder with a specific gravity of about 2.5 to 2.7 and a Mohs hardness of about 6.

The typical composition of the nepheline syenite powder is shown below.

SiO□=53~62-tχ (hereinafter simply expressed as %)
A1. O,: 19-24% NazO: 6-12%, O: 2-10% CaO: 0.5-3.5% Silicic anhydride 81-5 parts Silicic anhydride reduces gloss. Although it is a useful component, if the amount is less than 1 part, it will have poor gloss reduction effect, while if it exceeds 5 parts, it will deteriorate the adhesion and processability of the coating film, so it is preferably 1 to 5 parts. The amount was added in the range of 5 to 3 parts.

Mica: 5 to 50 parts Mica is useful as an auxiliary agent for reducing gloss, and also contributes effectively to improving weather resistance, abrasion resistance, adhesion, and processability. However, if the amount is less than 5 parts, it will not only have a poor gloss reduction effect, but also the above-mentioned coating film reinforcement effect, while if it exceeds 50 parts, it will deteriorate the fluidity of the paint and cause deterioration of paintability. The mica content was limited to 5 to 50 parts, preferably 8 to 30 parts.

Here, the above inorganic powder has a particle size of 0.3 to 100
It is desirable to use a material in the μm range.

This is because if the particle size of the inorganic powder is less than 0.3 μm, the paint will tend to thicken (and even when it becomes a paint film component, it will settle under the paint film, making it difficult to sufficiently improve hardness and scratch resistance. On the other hand, if the inorganic powder exceeds 100 μ-, strong stirring is required at all times in order to uniformly distribute the inorganic powder in the paint. Roll coaters, curtain flow coaters, and bar coaters This is because when applying with a shaving process, it becomes difficult to obtain a uniform coating film on the surface, and the inorganic powder is also likely to fall off, making it easier for cracks and peeling to occur during processing. .

Now, for film formation, a vehicle consisting of a suspension containing the various additives listed above in the preferred ranges above and diluted with a solvent as necessary is applied to the surface of the base steel sheet and baked to form a film. However, any conventionally known method such as a roll coater method, a curtain flow coater method, or a bar coater method can be used for the application, and the baking treatment can be performed at 180 to 300°C and 0.5°C. It is preferable to carry out the heating for about 5 to 3 minutes.

Further, as the base steel plate, not only general cold-rolled steel plates but also those subjected to chemical conversion treatment, plating treatment, and even brimer treatment can be suitably used.

The thickness of the coating after baking is preferably about 5 to 40 μm.

(Function) According to the present invention, by using a film-forming component that is a mixture of a bake-curable film-forming main element and a specific inorganic powder or hardened resin powder, it is possible to achieve low gloss, high hardness, and good scratch resistance. The reason why a coating film with good adhesion properties, weather resistance, corrosion resistance, workability, etc. can be obtained has not yet been clearly elucidated, but it is thought to be as follows.

In other words, it is thought that this is because the inorganic powder dispersed in the coating film not only exerts a particle reinforcing effect like pigments, but also functions as a stress relaxation function.

(Example) Example 1 Baking is an epoxy paint (
A, ): For 100 parts, nepheline syenite powder (white powder, average particle size 2.3 μm) = 5 parts, anhydrous silicic acid thyroid @244, average particle size 3 μm, manufactured by Fuji Davison): 5 parts , mica (WG-1000, average particle size 10μ
(manufactured by Ingrifushi Mica Co., Ltd.); 5 parts were mixed and stirred and mixed at 100 to 600 rpm using a stirrer to prepare a vehicle.

The above compounded paint was applied to a 0.35 m thick hot-dip galvanized steel plate (Z25) treated with zinc phosphate using a bar coater so that the dry film thickness was 10 μm, and then the maximum plate temperature was 200°C. Processing time: Baking was performed for 45 seconds.

The results of investigating the coating film properties of the low-gloss painted tone plates thus obtained are shown in Table 1 below.

As is clear from the results shown in Table 1, by adding a specific inorganic powder according to the present invention, it is possible to obtain a low A brightly painted steel plate was obtained.

Example 2 The same treatment as in Example 1 was performed except that polyacrylonitrile resin powder (average particle size: 17 μm, manufactured by Mitsubishi Rayon Co., Ltd.) was used instead of nepheline syenite powder.

Table 1 shows the results of investigating the coating film properties of the low-gloss coated steel sheet thus obtained.

Example 3 Potassium titanate fiber (Kubota potassium titanate fiber B, fiber length: 1° to 50 μm 1
The same treatment as in Example 1 was performed except that a single yarn diameter: 0.5 to 2.0 μm (manufactured by Kubota Tekko Co., Ltd.) was used.

Table 1 shows the results of investigating the coating film properties of the low-gloss coated steel sheet thus obtained.

Example 4 The blending ratio of the component (AI) used in Example 1, nepheline syenite powder, silicic anhydride, and mica was 100:10:
Table 1 shows the results of investigating the coating film performance of a low-gloss coated steel sheet obtained in the same manner as in Example 1 except that the coating was changed to 3;15.

As is clear from the results, even if the amount of inorganic powder added was increased, results similar to or better than those of Example 1 were obtained.

Example 5 The ingredients used in Example 2 (the blending ratio of Aυ, polyacrylonitrile resin powder, silicic anhydride, and mica was 100:
Table 1 shows the results of investigating the coating film performance of a low-gloss coated steel plate obtained in the same manner as in Example 2 except that the ratio was changed to 10:3:15.

Example 6 The blending ratio of the component (AI) used in Example 3, potassium titanate fiber, silicic anhydride, and mica was 100:10.
The results of investigating the coating film performance of a low-gloss coated steel sheet obtained in the same manner as in Example 3 except that the ratio was changed to 3:15 are as follows.
Shown in the table.

Example 7 The blending ratio of the component (A1) used in Example 1, nepheline syenite powder, silicic anhydride, and mica was 100:30:1.
A low-gloss coated steel plate was obtained in the same manner as in Example 1 except that the coating was changed to :50. Table 1 shows the investigation results regarding the coating film performance.

By increasing the amount of inorganic powder added, further improvement in scratch resistance was achieved.

Example 8 The blending ratio of the component (A,) used in Example 2, polyacrylonitrile resin powder, silicic anhydride, and mica was 100.
Example 2 except that the ratio was changed to: 30: 1: 50.
A low gloss coated steel plate was obtained in the same manner as above. Table 1 shows the investigation results regarding the coating film performance.

Example 9 The blending ratio of component (A1) used in Example 3, potassium titanate fiber, silicic anhydride, and mica was 100:30:
A low gloss coated steel plate was obtained in the same manner as in Example 3 except that the ratio was changed to 1:50. Table 1 shows the investigation results regarding the coating film performance.

Example 10 Baking was carried out in the same manner as in Example 1, except that polyester paint (A2) was used as the main element to form a hardening film, and then dispersed and mixed uniformly using a stirrer to form a vehicle. .

In addition, as a base W4 board, 0, 35 treated with zinc phosphate is used.
Epoxy-based brimer was applied as a brimer to a hot-dip galvanized steel sheet (Z25) to a dry film thickness of 5 μm, maximum plate temperature: 200°C, processing time: 30
A primer-treated steel plate baked under conditions of 2 seconds was used.

The above vehicle was applied as a top coat to the surface of this primer-treated steel plate using a roll coater so that the dry film thickness was 15 μm, and then baked under the conditions of maximum plate temperature: 240°C and processing time: 60 seconds. Ta.

Table 1 shows the results of examining the physical properties of the coating film of the thus obtained low-gloss coated steel sheet.

As is clear from the results in Table 1, by adding specific resin powders and inorganic powders to different types of paint, the hardness, scratch resistance, weather resistance, and corrosion resistance can be improved without reducing processability. Excellent low-gloss painted steel sheets have been obtained.

Example 11 Baking was carried out in the same manner as in Example 2, except that polyester paint (A2) was used as the main element to form a hardening film, and then dispersed and mixed uniformly using a stirrer to form a vehicle. .

The base steel sheet was a hot-dip galvanized steel sheet (Z25) with a zinc phosphate treatment and a thickness of 0.35 mm. An epoxy primer was applied as a primer to a dry film thickness of 5 μm, and the maximum plate temperature was 7200°C. A primer-treated steel plate was used which was baked under the conditions of treatment time: 30 seconds.

The above vehicle was applied as a top coat to the surface of this primer-treated steel plate using a roll coater so that the dry film thickness was 15 μm, and then baked under the conditions of a maximum plate temperature of 240°C and a processing time of 860 seconds. .

Table 1 shows the results of investigating the film properties of the low-gloss coated steel sheets thus obtained.

Example 12 Baking was carried out in the same manner as in Example 3, except that polyester paint (82) was used as the main element to form a hardening film, and then dispersed and mixed with a stirrer so as to be uniform. did.

In addition, as a base steel plate, an epoxy-based primer was applied as a primer to a 0.35 mm thick galvanized steel plate (Z25) treated with zinc phosphate to a dry film thickness of 5 μm, and the maximum plate temperature: 200 A primer-treated steel plate baked under conditions of temperature and treatment time of 30 seconds was used.

The above vehicle was applied as a top coat to the surface of this primer-treated steel plate using a roll coater so that the dry film thickness was 15 μm, and then baked under the conditions of maximum plate temperature = 240°C and processing time: 60 seconds. Ta.

Table 1 shows the results of investigating the film properties of the low-gloss coated steel sheets thus obtained.

Example 13 A vehicle obtained by blending a polyester paint (100 parts of A, 10 parts of nepheline syenite powder, 83 parts of silicic anhydride, and 15 parts of mica) and uniformly dispersing and mixing with a stirrer. A low-gloss coated steel plate was obtained in the same manner as in Example 10, except that the following was used as the top coat.Table 1 shows the results of investigating the coating film performance.

From the results shown in Table 1, even if the type of paint was changed and the amount added was increased, a low-gloss coated steel sheet with excellent physical properties of the paint film was obtained.

Example 14 Polyester paint (At): 100 parts, polyacrylonitrile resin powder: 10 parts, silicic anhydride 83 parts,
A low-gloss coated steel plate was obtained in the same manner as in Example 11, except that 15 parts of mica was blended, uniformly dispersed and mixed using a stirrer, and the resulting vehicle was used as the top coat. Table 1 shows the results of investigating the coating film performance.

Example 15 Polyester paint (A2): 100 parts, potassium titanate fiber: 10 parts, silicic anhydride 83 parts, mica: 1
Example 1 except that the vehicle obtained by blending 5 parts and uniformly dispersing and mixing with a stirrer was used as a top coat.
A low gloss coated steel plate was obtained in the same manner as in 2.

Table 1 shows the results of investigating the coating film performance.

Example 16 Polyester paint (Ih): 100 parts, nepheline syenite powder: 30 parts, silicic anhydride: 21 parts, mica: 50 parts. A gloss coated steel plate was obtained. The coating performance is shown in Table 1.

As is clear from the results in Table 1, it can be seen that by increasing the amount added within the appropriate range of the present invention, the scratch resistance can be further improved.

Example 17 Example 1 except that the blending ratio was changed to 7100 parts of polyester paint (A2), 30 parts of polyacrylonitrile resin powder, 21 parts of silicic anhydride, and 50 parts of mica.
A low gloss coated steel plate was obtained in the same manner as in Example 1. The coating performance is shown in Table 1.

Example 18 Polyester paint (Ih): 100 parts, potassium titanate fiber = 30 parts, silicic anhydride 21 parts, mica: 5
A low-gloss coated steel plate was obtained in the same manner as in Example 12 except that the blending ratio was changed to 0 parts. The coating performance is shown in Table 1.

Example 19 Polyester paint (Az): 100 parts, nepheline syenite powder: 5 parts, silicic anhydride = 2 parts, mica: 10 parts in the same manner as in Example 10 except for changing the blending ratio. A low gloss coated steel plate was obtained. The coating performance is shown in Table 1.

Even with this formulation, a low-gloss coated steel sheet with excellent coating film properties was obtained.

Example 20 Example 1 except that the blending ratio was changed to polyester paint (Ag): 100 parts, polyacrylonitrile resin powder: 5 parts, silicic anhydride: 82 parts, mica: 10 parts.
A low gloss coated steel plate was obtained in the same manner as in Example 1. The coating performance is shown in Table 1.

Example 21 Polyester paint (/h): 100 parts, potassium titanate fiber: 5 parts, silicic anhydride 22 parts, mica: 10
A low-gloss coated steel plate was obtained in the same manner as in Example 12, except that the mixing ratio was changed. The coating performance is shown in Table 1.

Example 22 Polyester paint (Ax) = 100 parts, nepheline syenite powder: 20 parts, silicic anhydride 24 parts, mica - 30 parts except that the blending ratio was changed in the same manner as in Example 10. A gloss coated steel plate was obtained.

It can be seen that even if a large amount of silicic anhydride is blended, as long as it is within the appropriate range of the present invention, a low-gloss coated steel sheet with excellent hardness and scratch resistance can be obtained without deteriorating weather resistance or workability.

Example 23 Polyester paint (Ax): 100 parts, polyacrylonitrile resin powder: 20 parts, silicic anhydride 24 parts,
A low-gloss coated steel plate was obtained in the same manner as in Example 11 except that the mixing ratio was changed to 30 parts of mica.

Example 24 Polyester paint (Az): 100 parts, potassium titanate fiber: 20 parts, silicic anhydride 24 parts, mica:
A low-gloss coated steel plate was obtained in the same manner as in Example 12 except that the blending ratio was changed to 30 parts.

Comparative Example 1 A low-gloss coated steel plate was obtained in the same manner as in Example 1 using only epoxy paint A.

Table 1 shows the results of coating film evaluation.

Those to which each inorganic powder was not added were inferior in hardness and scratch resistance.

Comparative Example 2 A low-gloss coated steel plate was obtained in the same manner as in Example 10 using only polyester-based At.

Table 1 shows the results of coating film evaluation.

When each inorganic powder was not added, only results similar to those of Comparative Example 1 were obtained.

Comparative Example 3 Same as Example 10 except that the blending ratio was changed to polyester paint (Az): 10 parts, nepheline syenite powder: 4 parts, silicic anhydride = 0.5 parts, mica: 4 parts. A low gloss coated steel plate was obtained by the method. The coating performance is shown in Table 1.

From the results in Table 1, when the amount of each inorganic powder was less than the appropriate range of the present invention, hardness and scratch resistance were poor, and a product with low gloss could not be obtained.

Comparative Example 4 The same method as in Example 11 except that the blending ratio was changed to 100 parts of polyester paint (Ax), 4 parts of polyacrylonitrile resin powder, 80.5 parts of silicic anhydride, and 4 parts of mica. A low gloss coated steel plate was obtained.

The coating performance is shown in Table 1.

Comparative Example 5 Polyester paint (Ax)? 100 parts, potassium titanate fiber: 4 parts, silicic anhydride 0.5 parts, mica:
A low gloss coated steel plate was obtained in the same manner as in Example 12 except that the blending ratio was changed to 4 parts. The coating performance is shown in Table 1.

Comparative Example 6 Polyester paint (Ax): 100 parts, nepheline syenite powder: 40 parts, silicic anhydride: 86 parts, mica: 60 parts. A gloss coated steel plate was obtained.

The coating performance is shown in Table 1.

If the amount added exceeds the appropriate range for this invention, the gloss, hardness, and scratch resistance were good, but the adhesion, processability, and paintability of the coating film were poor.

Comparative Example 7 Same as Example 11 except that the blending ratio was changed to polyester paint (Az): 100 parts, polyacrylonitrile resin powder: 4 parts, silicic anhydride = 0.5 parts, mica: 4 parts. A low gloss coated steel plate was obtained by the method.

The coating performance is shown in Table 1.

Comparative Example 8 Polyester paint (At): 100 parts, potassium titanate fiber: 4 parts, silicic anhydride 80.5 parts, mica:
A low gloss coated steel plate was obtained in the same manner as in Example 12 except that the blending ratio was changed to 4 parts. The coating performance is shown in Table 1.

(Effects of the Invention) Thus, according to the present invention, it is possible to achieve high hardness, corrosion resistance, and scratch resistance without the deterioration of paint film adhesion and weather resistance, which were concerns when reducing the gloss of conventional coated steel sheets. It is possible to obtain a low-gloss F4 temporary coating with excellent properties.

Claims (1)

[Claims] 1. As film-forming components, 100 parts by weight of a bake-curable film-forming main element and 5 to 50 parts by weight of at least one selected from nepheline syenite powder, polyacrylonitrile resin powder, and potassium titanate fiber. A low-gloss coated steel sheet obtained by applying and baking a vehicle containing silicic anhydride: 1 to 5 parts by weight, and mica: 5 to 50 parts by weight onto the surface of a base steel sheet.