KR102167674B1 - Coating Composition for Manufacturing Pre-Coated Metal Color Sheet of Fluorin Mat Type and Color Sheet Using the Same - Google Patents

Abstract

The present invention relates to a PM coating composition for manufacturing a fluorine mat-type color steel sheet, and a fluorine mat-type color steel sheet manufactured thereby, while forming particles and wrinkles equivalent to those of a conventional polyester-based mat-type color steel sheet, and corrosion resistance and weather resistance. It aims to improve physical properties such as.
To this end, the present invention relates to a PM coating composition for manufacturing a PM color steel plate, which is applied to the surface of a PCM (Pre-Coated Metal) steel plate to form wrinkles on the surface of the coating film, wherein the PM coating comprises the entire composition. Based on the fluorine-based resin 40 to 50% by weight, hardener 2 to 8% by weight, pigment 20 to 30% by weight, solvent 25 to 35% by weight, and additives 2 to 4% by weight are included, and the fluorine-based resin is a thermosetting type Phosphorus FEVE (Fluoro Ethylene-Alkyl Vinyl Ether) resin, characterized by having a solid content of 50 to 70%, an acid value of 3 to 5 mgKOH/g, and a glass transition temperature of 10 to 30°C.

Description

Fluorinated mat type PM color steel sheet manufacturing PM coating composition and fluorine mat type color steel sheet manufactured thereby {Coating Composition for Manufacturing Pre-Coated Metal Color Sheet of Fluorin Mat Type and Color Sheet Using the Same}

The present invention relates to a PM coating composition for manufacturing a fluorine mat type PM color steel sheet, and a fluorine mat type color steel plate manufactured thereby, and more particularly, to a PM color steel plate in which wrinkles are formed on the coating surface. Corrosion resistance compared to conventional matt color steel sheets by using FEVE ((Fluoro Ethylene-Alkyl Vinyl Ether)) which is a thermosetting type fluorine-based resin without using conventional polyester resin or thermoplastic resin PVDF (Polyvinylidene Difluoride). , To a fluorine mat type PM color steel sheet manufacturing PM coating composition that can greatly improve physical properties such as durability and weather resistance, and a fluorine matt type color steel sheet manufactured thereby.

The steel sheet coating method includes a post-coating method in which a steel sheet is coated after molding and a pre-coating method in which a steel sheet is pre-painted before molding.

The steel sheet painted by the above pre-coating method is commonly referred to as a pre-coated metal steel sheet, and the paint is referred to as a'PCM paint'.

The PM steel sheet coated with the above PM paint is subjected to a separate processing process after painting. Accordingly, the PCM paint must satisfy conditions such as excellent workability, film hardness, adhesion, weather resistance, corrosion resistance, and curability.

Among the PM color steel sheets, there is a color steel sheet used as a building material such as a roof or wall by forming a wrinkle on the surface of the coating film (hereinafter, this will be referred to as a'Mat type color steel sheet').

The PM paint used in the manufacture of the above-described matte color steel sheet contains a polymeric polyester resin as a base resin and a melamine resin compound as a crosslinking agent, and a small amount of additives such as a curing catalyst, a defoaming agent and a leveling agent are added. have.

However, in the conventional matte type PM color steel sheet, it is difficult to expect further improvement in durability and weather resistance due to the limitation of physical properties of the polyester resin as the main component.

Recently, extreme weather events caused by global warming are emerging as a global problem, and extreme weather events such as heat waves, heavy rains, and cold waves are getting worse and worse on the Korean Peninsula.

This is no longer a temporary climate change, but a long-term climate change.

Accordingly, a problem has been pointed out that the conventional polyester-based matte color steel sheet, which is widely used as a roofing material for buildings, cannot adequately cope with the severe climate change as described above.

KR 10-2015-0036883 A KR 10-1432175 B1

The present invention is to solve the above-described problems of the prior art, and provides a PM coating composition capable of forming particles and wrinkles equivalent to those of a conventional polyester mat-type color steel sheet without using a polyester resin. It has its purpose.

Another object of the present invention is to provide a PM coating composition capable of improving corrosion resistance, durability, and weather resistance while having the same processability, coating hardness, and adhesion as a conventional polyester-based matt color steel sheet.

In order to achieve the above object, the present invention provides a PM coating composition for manufacturing a PM color steel plate, which is applied to the surface of a PCM (Pre-Coated Metal) steel plate to form wrinkles on the surface of the coating film, wherein the PM coating material Is composed of 40 to 50% by weight of a fluorine-based resin, 2 to 8% by weight of a curing agent, 20 to 30% by weight of a pigment, 25 to 35% by weight of a solvent, and 2 to 4% by weight of an additive, based on the total composition. The resin is a thermosetting type FEVE (Fluoro Ethylene-Alkyl Vinyl Ether) resin, characterized by having a solid content of 50 to 70%, an acid value of 3 to 5 mgKOH/g, and a glass transition temperature of 10 to 30°C.

In addition, the curing agent is characterized in that it is made of an isocyanate resin or a melamine resin.

In addition, the additive is characterized in that it comprises 0.5 to 1.0% by weight of an acid catalyst, 0.5 to 1.0% by weight of an antifoam, 0.5 to 1.0% by weight of a matting agent, and 0.5 to 1.0% by weight of an amine additive.

According to the present invention, there is an effect of forming particles and wrinkles equivalent to those of a conventional polyester-based matt color steel sheet without using a polyester resin.

In addition, there is an effect of manufacturing a fluorine mat-type color steel sheet with improved corrosion resistance, durability, and weather resistance while having the same workability, coating hardness, and adhesion as the existing PM mat-type color steel sheet, which is mainly composed of polyester resin.

1 is a photograph of a polyester-based mat-type color steel sheet manufactured by the prior art.
Figure 2 is a photograph of a fluorine-based mat-type color steel sheet manufactured according to the present invention.

The PM coating for manufacturing a fluorine mat-type color steel sheet according to the present invention includes a resin, a curing agent, a pigment, a solvent, and an additive, like a general PM coating.

Hereinafter, each component of the fluorine mat type PM coating composition according to the present invention will be described.

<Fluorine resin>

In the present invention, a fluorine-based resin is used, and among the fluorine-based resins, PVDF, a thermoplastic fluorine resin, is not used, and a thermosetting type FEVE (Fluoro Ethylene-Alkyl Vinyl Ether) resin is used.

PVDF (Polyvinylidene difluoride) resin, which is widely used in PM steel sheets, is a fluorine-based thermoplastic resin and has a characteristic of maintaining soft characteristics even after curing of a coating film.

Accordingly, it is difficult to clearly form a sense of grain and a wrinkle pattern on the surface of the steel sheet.

However, according to the present invention, the above problem can be solved by using a thermosetting type FEVE resin among fluorine-based resins.

The FEVE has excellent weather resistance and mechanical properties while protecting vinyl ether monomers, which are weak in UV and chemical resistance, by fluorine ethylene monomers through a very regular copolymer structure.

In other words, the FEVE resin is enhanced by protection of carbon-carbon or carbon-hydrogen bonds electronically or sterically by fluorine, and improves weather resistance by blocking deterioration due to ultraviolet rays or the like.

In addition, Alkyl vinyl ether in FEVE allows the fluorine-based resin to be dissolved in a solvent, gives gloss, and improves mechanical properties such as hardness and processability.

However, when the content of the FEVE resin exceeds 50%, processability and chemical resistance are weakened, and when the content is less than 40%, durability and weather resistance are reduced.

Therefore, the content of the FEVE resin is preferably 40 to 50% by weight based on the total coating composition.

In addition, it is preferable that the FEVE resin has a solid content of 50 to 70%, an acid value of 3 to 5 mgKOH/g, and a glass transition temperature of 10 to 30°C.

<hardener>

The curing agent, as a component forming a coating film together with the FEVE resin, is an isocyanate resin or a melamine resin.

As the isocyanate resin curing agent, it is preferable to use a hexaethylene diisocyanate condensate or a blocked non-yellowing isocyanate, and as a melamine-based curing agent, methylated or butylated melamine is preferably used.

Since the weather resistance of the curing agent is worse than that of the FEVE resin, it is recommended to add a small amount compared to the FEVE resin. For example, it is recommended to mix and use the FEVE resin and the curing agent in the range of 5:1 to 11:1.

When the content of the curing agent exceeds 8% by weight, overall properties of the coating film such as weather resistance are deteriorated, and when the content of the curing agent is less than 2% by weight, the coating layer is not sufficiently cured, and thus coating properties such as solvent resistance and hardness may decrease.

Therefore, the curing agent is preferably contained in an amount of 2 to 8% by weight based on the total composition.

<Pigment>

Pigment is a colored powder that does not dissolve in a solvent, and is used by dispersing it into very fine particles (0.1 ~ 20mm) in the paint. Pigments play a role in embodying color and imparting hiding power in the paint.

In the present invention, color pigments such as titanium oxide (TiO2), carbon black, iron oxide, and chromium antimony titanium buff rutile are used, and 20 to 30 weights based on the total coating composition Included in% range.

<solvent>

The solvent plays a role of lowering the viscosity by diluting it appropriately for painting when the paint has no fluidity at room temperature or is difficult to paint due to high viscosity.

The solvent added to the coating composition of the present invention must be able to disperse the FEVE resin and other components.

As the organic solvent, aliphatic hydrocarbon (Hydrocarbon), aromatic hydrocarbon, ester (Ester), ketone (Ketone) solvent, or the like may be used alone or in an appropriate mixture.

Examples of the aliphatic hydrocarbon-based solvent include mineral split and kerosene, and examples of the aromatic hydrocarbon-based solvent include toluene, xylene, and solvent naphtha.

Examples of the ester solvent include ethyl acetate, butyl acetate, and amyl acetate, and examples of the ketone solvent include acetone and methyl ethyl ketone.

It is preferable to contain the said solvent in the range of 25 to 35 weight% with respect to the total coating composition.

<Other additives>

The basic components of paints are resins, pigments, and solvents, but it is difficult to satisfy many performances required for paints alone. Accordingly, it is desirable to improve the physical properties of the paint by adding various additives, and although the amount of the additive is small, it plays a very important role in the paint.

Since the types of additives are divided according to functions and uses, and may also vary depending on the type of paint, it is necessary to select an additive suitable for the paint.

The additives used in the present invention include an acid catalyst, a defoaming agent, a matting agent, and an amine-based additive, the acid catalyst is 0.5 to 1.0% by weight, the antifoam is 0.5 to 1.0% by weight, the matting agent is 0.5 to 1.0% by weight, It is preferable to contain 0.5 to 1.0% by weight of the amine additive.

The acid catalyst assists the melamine curing agent, and the antifoaming agent controls the air bubbles in the paint to form an excellent product appearance.

The matting agent plays a role in controlling the gloss, making the fluorine matte color steel sheet look more luxurious.

The amine additive is an additive that plays a large role in forming the pattern of the steel sheet, and it reacts with the acid catalyst to rise above the surface of the coating film, thereby forming a wrinkled pattern and a grainy texture.

Hereinafter, a comparative test result of each physical property of a fluorine-based mat-type PM color steel sheet prepared using the fluorine mat-type PM coating composition according to the present invention and a conventional polyester-based mat-type color steel sheet will be described.

As for the test piece, a 0.45T GI steel sheet was degreased with methyl ethyl ketone, a coating composition was applied, and a dry film thickness of 20 µm was prepared, followed by testing.

<hardness>

The degree of curing was measured according to the ASTM D5402 test method.

In other words, place the test piece horizontally and fix it with one hand, and with the other hand, wrap 4-6 pieces of gauze around your finger and apply an appropriate amount of solvent (Methyl Ethyl Ketone) and rub the surface of the film up and down to expose the material. When the test was finished, the number of times up to this time was measured.

As for the degree of curing, the fluorine-based mat-type color steel sheet according to the present invention exhibited two times or more excellent results compared to the conventional polyester-based mat-type color steel sheet.

<Processability>

For workability, a test specimen was prepared according to the KS D 3520 bending test test method, and then T-Bending was performed at 180 degrees using a vise.

At this time, the processability was evaluated by attaching a tape having a length of about 75 mm to the processing area using a transparent adhesive tape, and then peeling it off at an angle of 60 degrees at a uniform speed between 0.5 and 1 second.

The workability showed good results in both the conventional polyester-based matt color steel sheet and the fluorine-based matt color steel sheet of the present invention.

<Naeboiling Mercury>

Boiling water resistance was evaluated according to the KS D 8303 Boiling Water Test Method.

That is, the temperature of the hot-water bath was maintained at 95 to 100°C, and after 1 hour, the test piece was placed in the constant-temperature bath, and after 1 hour, the test piece was taken out and washed with water to observe the presence or absence of the coating film.

The boiling water resistance showed good results in both the conventional polyester-based matt color steel sheet and the fluorine-based matt color steel sheet of the present invention.

<Coating adhesion>

Coating film adhesion was evaluated according to the ASTM D3359 test method.

That is, the test piece was cross-cut at 1 mm intervals by 100 cells, placed on an Erichsen tester, a radial punch was placed adjacent to it, and then pushed to a depth of 6 mm to conduct a tape adhesion test on the molded part.

The coating film adhesion showed excellent results in both the conventional polyester-based matt color steel sheet and the fluorine-based matt color steel sheet of the present invention.

<Acid resistance>

Acid resistance was evaluated according to the KS M ISO 2812-1 test method.

That is, the cut surface of the test piece is completely protected with a reagent and a tape that can withstand the test period, put a 5% HCl reagent in a beaker, and completely immerse the test piece so that it does not come into contact with the beaker. Observed.

In acid resistance, the fluorine-based mat-type color steel sheet of the present invention exhibited twice as excellent results as the conventional polyester-based mat-type color steel sheet.

<Alkaline resistance>

The alkali resistance was evaluated according to the KS M ISO 2812-1 test method.

In other words, the cut surface of the test piece is completely protected with a reagent and a tape that can withstand the test period, put a 5% NaOH reagent in a beaker, and completely immerse the test piece so that it does not come into contact with the beaker. Observed.

In terms of alkali resistance, the fluorine-based mat-type color steel sheet of the present invention exhibited three times better results than the conventional polyester-based mat-type color steel sheet.

<Pencil hardness>

Pencil hardness was evaluated according to the KS D 3520 pencil hardness test test method.

That is, the test piece was fixed to the pencil hardness tester, and the pencil was sharpened so that the tip was smooth and the angle was sharp so that the core was exposed about 3 mm, and then bound to the hardness tester at an angle of about 45 degrees.

Subsequently, a 1 kg load was applied to draw a line repeatedly 5 times so that the length was 20 mm or more, and the test area was erased with an eraser and observed with the naked eye.

The pencil hardness showed good results in both the conventional polyester-based matt color steel sheet and the fluorine-based matt color steel sheet of the present invention.

<corrosion resistance>

Corrosion resistance was subjected to a salt spray test according to ASTM D B1117.

That is, the cut surface of the test piece was sealed with tape to protect it, and after 500 hours had elapsed, the degree of occurrence of white rust and blister on the flat part of the test piece was observed.

In terms of corrosion resistance, the fluorine-based mat-type color steel sheet of the present invention was twice as excellent as the conventional polyester-based mat-type color steel sheet.

<Moisture resistance>

Moisture resistance was evaluated according to ASTM D 2247.

That is, the conditions of the wet tester were set at a temperature of 49±1° C. and a relative humidity of 95% or more, and the test piece was fixed to a sample holder and held for 1000 hours, and then the degree of blister generation was observed.

In terms of moisture resistance, the fluorine-based mat-type color steel sheet of the present invention exhibited three times better results than the conventional polyester-based mat-type color steel sheet.

<Weather resistance>

Weatherability was evaluated using a Q-LAB's QUV accelerated weatherability tester according to ASTM G154.

In particular, using a UV-B (313nm) fluorescent lamp, 4 hours of UV irradiation (60±3℃) and 4 hours (50±3℃) of condensation were repeated, and the color difference value was measured compared to the standard sample. I did.

The weather resistance of the fluorine-based mat-type color steel sheet of the present invention exhibited five times better results than the conventional polyester-based mat-type color steel sheet.

Accordingly, the fluorine mat-type color steel sheet according to the present invention may be usefully used for a roof or a wall exposed to a harsh climate environment.

[Table 1] below summarizes the above experiment results.

Experimental results of the conventional polyester-based matt color steel sheet and the fluorine-based matt color steel sheet of the present invention division Conventional polyester mat type
Color steel plate According to the invention
Fluorine mat type color steel sheet Film thickness 25㎛ 25㎛ Hardness △(50-60 times) ◎(100 times or more) Processability ○ ○ Boiling water resistance ○ ○ Adherence ◎ ◎ Acid resistance 24 hours good 72 hours good Alkali resistance 24 hours good 72 hours good Pencil hardness H H Corrosion resistance 500 hours good 1,000 hours good Moisture resistance 1,000 hours good 2,000 hours good Weather resistance 500 hours good 3,000 hours good △Medium, ○Good, ◎Excellent

As can be seen from [Table 1] above, the fluorine-based mat-type color steel sheet according to the present invention secures the same processability as compared to the conventional polyester-based mat-type color steel sheet, while acid resistance and alkali resistance are 3 times, corrosion resistance and Moisture resistance showed two times excellent results. In particular, the weather resistance of the fluorine-based mat-type color steel sheet of the present invention showed a whopping five times superior results compared to the conventional polyester-based mat-type color steel sheet.

1 is a photograph of a conventional polyester-based mat-type color steel sheet, and FIG. 2 is a photograph of a fluorine-based mat-type color steel sheet according to the present invention.

When comparing FIGS. 1 and 2, it can be seen that the fluorine-based mat-type color steel sheet according to the present invention has the same level of graininess and wrinkle pattern as the conventional polyester-based mat-type color steel sheet without using a polyester resin. have.

That is, the fluorine-based mat-type color steel sheet according to the present invention greatly improves acid resistance, alkali resistance, corrosion resistance, moisture resistance, and weather resistance, while forming the same level of graininess and wrinkle pattern as compared to the conventional polyester-based matt color steel sheet. There can be.

Accordingly, it can be usefully used for roofs or walls of buildings exposed to harsh climate environments.

In the above, preferred embodiments of the present invention have been exemplarily described, and the scope of the present invention is not limited to the specific embodiments described above. Those of ordinary skill in the art will understand that various changes and modifications can be made without departing from the scope of the technical idea of the present invention.

Claims (4)

In the PM coating composition for manufacturing a PM color steel plate, which is applied to the surface of a PCM (Pre-Coated Metal) steel plate to form wrinkles on the surface of the coating film,
The PM coating comprises 40 to 50% by weight of a fluorine-based resin, 2 to 8% by weight of a curing agent, 20 to 30% by weight of a pigment, 25 to 35% by weight of a solvent, and 2 to 4% by weight of an additive based on the total composition. under,
The fluorine-based resin,
As a thermosetting type FEVE (Fluoro Ethylene-Alkyl Vinyl Ether) resin, it has a solid content of 50 to 70%, an acid value of 3 to 5mgKOH/g, and a glass transition temperature of 10 to 30℃.
The curing agent is made of an isocyanate resin or a melamine resin,
As the isocyanate resin curing agent, a hexaethylene diisocyanate condensate or a blocked non-yellowing isocyanate is used,
As the melamine-based curing agent, methylated or butylated melamine is used,
The FEVE resin and the curing agent are blended in the range of 5:1 to 11:1,
The pigment is titanium oxide (TiO2), carbon black (Carbon black), iron oxide (Iron oxide), chromium antimony titanium buff rutile (Chrome antimony titanium buff rutile) is used,
The solvent is an aliphatic hydrocarbon (Hydrocarbon)-based, aromatic hydrocarbon-based, ester (Ester)-based, ketone (Ketone)-based solvent used alone or in combination,
The additive is a PM coating composition comprising 0.5 to 1.0% by weight of an acid catalyst, 0.5 to 1.0% by weight of an antifoaming agent, 0.5 to 1.0% by weight of a matting agent, and 0.5 to 1.0% by weight of an amine additive. delete delete delete

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