KR100965736B1 - Precoating composition - Google Patents

Abstract

The present invention is a pre-coating coating composition comprising a binder resin, a curing agent, a solvent, and an additive, the magnetic pigment of which the arrangement is adjusted according to the magnitude or direction of the magnetic force to form a predetermined color or pattern ( It relates to a coating composition for pre-coating, characterized in that it contains a magnetic pigment).

The coating composition for pre-coating of the present invention includes a magnetic pigment capable of forming a predetermined color and pattern by adjusting the arrangement according to a magnetic force, thereby forming various three-dimensional patterns on the substrate according to the magnetic force, as well as excellent mechanical properties. The coating film layer which has is formed.

Paint composition, color steel sheet

Description

Coating composition for pre-coating {PRECOATING COMPOSITION}

The present invention relates to a coating composition for pre-coating comprising a magnetic pigment that can be adjusted in the arrangement by the magnetic force.

Generally, metal coating methods are classified into a post-coating method of coating after a molding process and a pre-coating method of coating before a molding process. Post-coating method is inexpensive equipment cost, is advantageous for small quantity production, while there is a disadvantage that uniform product and mass production is difficult. On the other hand, the pre-coating method has the advantages of not only the safety of the work, the uniformity of the product and the reduction of paint loss, but also less environmental pollution and mass production in a short time. Here, the steel sheet coated with the metal to be formed by a pre-coating method is called a pre-coated metal (hereinafter referred to as 'PCM') or a color steel sheet, and the paint used therein is called a PCM paint.

Since the steel sheet coated with the pre-coating, that is, the color steel sheet, undergoes a separate molding process after coating, the adhesion between the steel sheet and the coating film is excellent, the surface is beautiful, and the coating film is peeled off even if roll forming, bending and pressing work are performed. It is excellent in workability such that no phenomenon occurs. For this reason, color steel sheets are widely used in various applications such as interior and exterior materials of construction, household products, and assembly metals.

These color steel sheets are generally manufactured by 2 Coat-2 Bake System after pretreatment. First, electrolytic or hot-dip galvanizing zinc and zinc alloys on the surface of the steel sheet, and then applying a pretreatment agent (eg, chromium or silica) to the plated steel sheet to prevent corrosion, and then perform a pretreatment process. When the steel sheet is subjected to a hard coat, top coat or clear coating process in turn and then subjected to a hardening process, a prepainted steel sheet is manufactured. However, in order to exhibit a pattern on the cured color steel sheet, conventionally, the ink of the natural drying type is repeatedly applied one to three times by roll coating or curtain flow on the cured coating film. Is common. However, when a pattern is formed on the surface of the steel sheet by this method, the adhesion between the cured coating film and the ink of the steel sheet is reduced, resulting in a decrease in coating film properties such as weather resistance and workability. In addition, when a three-dimensional pattern is to be formed, the process is complicated due to repetitive painting, and the manufacturing cost is also increased because expensive ink is used several times.

The inventors of the present invention have a magnetic pigment that can be arranged in accordance with a magnetic force in a coating composition used for top coat, bottom coat or clear coating to form a predetermined color or pattern. It has been found that the alignment of the magnetic pigments can be adjusted according to the magnetic force by passing through the magnetic field before the substrate is cured to form various three-dimensional patterns.

The present invention is based on this.

The present invention is a pre-coating coating composition comprising a binder resin, a curing agent, a solvent and an additive, the magnetic pigment that is arranged according to the size or direction of the magnetic force to form a predetermined color or pattern ( It provides a coating composition for pre-coating characterized in that it contains a magnetic pigment).

The coating composition for pre-coating of the present invention includes a magnetic pigment capable of forming a predetermined color and pattern by adjusting the arrangement according to a magnetic force, thereby forming various three-dimensional patterns on the substrate according to the magnetic force, as well as excellent mechanical properties. The coating film layer which has is formed.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The coating composition for pre-coating according to the present invention includes a magnetic pigment whose arrangement is adjusted according to the arrangement or intensity of the magnetic force to form a predetermined color or pattern, thereby allowing a simple manner of passing the magnetic field without deteriorating the mechanical properties of the coating layer. It is characterized by expressing various three-dimensional patterns in various colors or patterns on the surface of the substrate.

Pigments are substances which are not dissolved in liquids such as water and organic solvents and are colored on the surface of the substrate in a dispersed state. Inorganic pigments such as oxides such as zinc, titanium, iron, copper, and chromium, phthalocyanine pigments, and azo pigments And organic pigments such as.

Some of these pigments have pigments having magnetic properties that are aligned in the direction of the lines of magnetic force or in the direction opposite to the direction of the lines of magnetic force when a magnetic field is applied. Such pigments are called magnetic pigments.

Specifically, the magnetic pigment particles have a property that when the magnetic field is applied, the magnetic pigment particles are arranged at different angles by rotating the magnetic pigment particles by a certain angle in a predetermined direction according to the intensity or direction of the applied magnetic force.

When light having a specific wavelength such as visible light is incident on the magnetic pigment having such a property, the incident light is absorbed or reflected by the magnetic pigment. At this time, the color may be colored by reflecting light differently according to the arranged angle of the magnetic pigment, or may be colored by the light reflected by the magnetic pigment and the light refracted-reflected in the magnetic pigment interfere with each other. In addition, since the magnetic pigment is generally a material having a certain thickness, it is possible to form various patterns on the surface of the steel sheet by changing the arrangement of the magnetic pigment in accordance with the magnetic field. In addition, since each of the magnetic pigment particles has a specific shape such as a plate shape (coin type, flake type, etc.), the light incident on the pigment may be differently reflected for each magnetic pigment particle to form various colors or patterns. .

Therefore, the present invention includes a magnetic pigment having such a property in the coating composition for pre-coating, thereby allowing a predetermined method to be applied to the surface of the substrate by a simple manner of passing the substrate coated with the coating composition for pre-coating into the magnetic field before curing. Colors or patterns can be formed. In this case, the present invention can easily form a desired color or pattern on the surface of the substrate by changing only the strength or direction of the magnetic field, thereby easily expressing various patterns. In addition, the present invention is different from the conventional method of coating ink on the cured coating layer several times in order to form a pattern on the cured color base material. Therefore, since the ink is not used, the adhesion between the coating film and the ink is lowered and the mechanical properties of the coating film are reduced. Deterioration of physical properties does not occur.

<Magnetic pigment>

The coating composition for precoating of this invention contains a binder resin, a magnetic pigment, a hardening | curing agent, a solvent, and an additive.

The magnetic pigment may be used without particular limitation, as long as the magnetic pigment can be adjusted by magnetic force while absorbing or reflecting light of a specific wavelength. Non-limiting examples of such magnetic pigments include iron-containing pigments, nickel-containing pigments, cobalt-containing pigments, and more specifically carbonyl iron and the like. As described above, when the base material coated with the coating composition for pre-coating including the magnetic pigment passes the magnetic field before curing, the magnetic pigment is arranged and arranged only by changing the intensity or direction of the applied magnetic field. The angle may be adjusted, and thus incident light may be absorbed or reflected differently to form various colors or patterns.

The shape of the magnetic pigment is not particularly limited, but may be spherical, tube, fiber, rod or plate, and the shape of each magnetic pigment particle may be the same or different from each other. have. Among these forms, it is preferable to use a plate-shaped magnetic pigment such as a coin shape. Because, when the plate-shaped magnetic pigment is rotated by a fine angle by the magnetic force, the plate-shaped magnetic pigment is clearly different from the spherical magnetic pigment even if the angle difference before and after the rotation is minute. For this reason, in the case of the plate-shaped magnetic pigment, the difference between the reflection angle of the light incident on the pigment before the pigment rotates and the reflection angle of the light incident on the pigment after the pigment rotates becomes apparent. Therefore, the plate-shaped magnetic pigments which can easily adjust the arrangement position and the angle of arrangement of the magnetic pigments, rather than other types of magnetic pigments, are advantageous for forming various colors or patterns.

In addition, like the general pigment, the magnetic pigment has a smaller particle size, and the coloring power is good and the sharpness is higher. Therefore, in the present invention, it is preferable to use a magnetic pigment having an appropriate size according to the degree of concealment required, and for example, a magnetic pigment having an average size (particle size) of about 10 to 40 μm can be used. If the average size of the magnetic pigment is small, the dispersed pigment particles re-aggregate with each other to form a seed, which may result in a drag phenomenon of the pigment by the roller, and there may be an unpainted portion on the surface of the coating film. In addition, due to the aggregation of the particles, light incident on the particles may be diffusely reflected to prevent a desired color or pattern from being formed. On the other hand, if the average size of the magnetic pigment is too large, the hiding power of the paint is weakened, so that a lot of magnetic pigment should be added, and the pigment is attracted by the roll when it is coated by the roll coating method. A phenomenon may occur and an uncoated portion of the surface of the coating film may occur. Therefore, it is preferable to adjust the average size (particle diameter) of a magnetic pigment suitably.

The content of the magnetic pigment may be appropriately adjusted in consideration of the color and mechanical properties of the coating film to be formed, preferably about 5 to 50 parts by weight based on 100 parts by weight of the binder resin. If the content of the magnetic pigment is too small, an unstable pattern may be formed on the surface of the coating film, and it may be difficult to express a desired color. In addition, if the content of the magnetic pigment is too large, the binder resin is insufficient, and the magnetic pigment cannot be properly adhered to the substrate, and the manufacturing cost may increase.

<Binder Resin>

The coating composition for pre-coating of the present invention includes a binder resin that gives durability to the coating film and fixes the pigment to the surface to be coated.

The binder resin may be used without particular limitation as long as it is used in the coating composition for pre-coating in the art, for example, polyester resin, acrylic resin or epoxy resin.

The polyester resin is produced by esterification of a polybasic acid component and a polyhydric alcohol component. Examples of the polybasic acid component include phthalic anhydride, isophthalic acid, telephthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, dicarboxylic hydrogenated bisphenol A, and hydrogenated dimer acid. Hydrogenated naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, tricyclodecanedicarboxylic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, One or more dibasic acids selected from maleic anhydride and the like and lower alkyl esters of these acids can be used, and monobasic acids such as benzoic acid, crotonic acid and pt-butyl benzoic acid, trimellitic anhydride, methyl Trivalent or more polybasic acids, such as cyclohexenic carboxylic acid and pyromellitic anhydride, etc. can be used together. Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, and 1,4-hexane Dihydric alcohols such as diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, alkylene oxide adducts of bisphenol A and / or bisphenol F, tricyclodecane glycol and the like can be used If necessary, trihydric or higher polyhydric alcohols such as glycerin, trimethylol ethane, trimethylolpropane, pentaerythritol and the like may be used in combination. These polyhydric alcohols can be used individually or in mixture of 2 or more types.

Such a polyester resin preferably has a number average molecular weight within the range of about 2,500 to 20,000 depending on the use of the coating composition. If the number average molecular weight of the polyester resin is less than 2,500, the coating film having sufficient durability on the surface of the substrate may not be formed, the pigment may not be properly adhered to the substrate, and the mechanical properties of the coating film on the surface of the substrate may be deteriorated. In the case of more than 20,000, workability may be deteriorated due to too low paint non-volatile content during application. Therefore, when the coating composition for precoating of the present invention is applied to interior and exterior building materials, it is preferable that a polyester resin having a number average molecular weight of about 2,500 to 6,000 is used. In the case of high processing using the coating composition for precoating of the present invention, a polyester resin having a number average molecular weight of about 7,000 to 9,000 is used, and in the case of deep processing using the coating composition as in home appliances It is appropriate that a polyester resin having a number average molecular weight of about 10,000 to 20,000 is used.

Moreover, it is preferable to use the polyester resin whose glass transition temperature is about -15-70 degreeC. If the glass transition temperature of the polyester resin is too low, because the glass transition temperature of the dried coating film is low, the coating film is weak, and panels may adhere to each other when loading or coiling at a low temperature. If the transition temperature is too high, the flexibility of the coating may be inferior, resulting in cracking or peeling of the coating.

In addition, the polyester resin preferably has a hydroxyl value of about 1 to 200 mgKOH / g. If the polyester resin having a hydroxyl value of less than 1 mgKOH / g may lower the crosslinkability of the coating film, the polyester resin having a hydroxyl value of more than 200 mgKOH / g may cause popping during operation, and the weather resistance thereof may be reduced. Can be.

Examples of the epoxy resins include glycidyl ether type epoxy resins, glycidylamine type epoxy resins, cyclic aliphatic epoxy resins, glycidyl ester resins, heterocyclic epoxy resins, urethane modified epoxy resins, and the like. Specifically, the glycidyl ether type epoxy resins include bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol. There are novolak type, cresol novolak type, DPP novolak type, trifunctional type, tris-hydroxyphenylmethane type, tetraphenylol ethane type and the like. The glycidylamine type epoxy resin is tetraglycidyldia. Minodiphenylmethane, triglycidyl isocyanurate, hydantoin type, 1,3-bis (N, N- diglycidylaminomethyl) cyclohexane, aminophenol type, aniline type, toluidine type and the like. However, this is not limitative.

It is preferable to use those epoxy resins whose equivalent is about 500-2,100. If the epoxy resin having an equivalent weight of less than 500 may be cured, the epoxy resin having an equivalent weight of more than 2,100 may lower the adhesive strength and chemical properties.

Non-limiting examples of the acrylic resin include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate and cyclohexyl acrylate. , Methyl methacrylate, atyl methacrylate, hexyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, styrene, acrylic acid, methacrylic acid, glycidyl acrylate And glycidyl methacrylate include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and the like.

Such acrylic resin is preferably used having a number average molecular weight of about 5,000 to 10,000. If the number average molecular weight of the acrylic resin is less than 5,000, the hardness of the resin may be too high to reduce the processability of the paint. If the number average molecular weight of the acrylic resin is more than 10,000, the surface hardness is low to lower the mechanical strength of the coating film. As a result, the panels may be attached to each other when coiling.

<Hardener>

The coating composition for precoating of this invention contains the hardening | curing agent which hardens | cures with binder resin in the coating film inside and outside. Such hardeners include melamine resins, urethane resins, urea resins, or mixtures thereof, but are not limited thereto.

Specifically, the melamine resin is a material obtained by the polymerization of alcohol and formaldehyde, for example, the methoxy melamine resin is a polymerization of methanol and formaldehyde; Butoxy melamine resins can be obtained by polymerization of iso-butanol or normal butanol with formaldehyde. Examples of the melamine resin obtained by such polymerization include, but are not limited to, alkyletherized melamine resins such as hexamethoxymethylmelamine resin, butoxymelamine resin, methylolated melamine resin and the like.

Moreover, a urethane resin is a substance obtained by superposition | polymerization of polyisocyanate, a polyol, and hydroxyacrylate or hydroxymethacrylate, and will not restrict | limit especially if it is a compound which has a -NCO group known in the art. Non-limiting examples of such urethane resins include polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene ether glycol (PTMG), polycondensation system, and lactone depending on the type of polyol. (Lactone) type, polycarbonate polyol, polybutadiene polyol, and the like.

Non-limiting examples of urea resins also include methylol ureas such as urea formaldehyde resins, alkoxy ureas such as butylated urea formaldehyde resins, and the like.

It is preferable that the above-mentioned hardening | curing agent is contained about 20-50 weight part with respect to 100 weight part of binder resins. If the content of the curing agent is less than 20 parts by weight, curing may not occur properly. If the content of the curing agent is more than 50 parts by weight, the physical properties of the coating film may be reduced or a coating film having a desired glossiness may not be formed.

<Solvent>

In this invention, the conventional solvent contained in a coating composition can be used. Non-limiting examples thereof include aromatic hydrocarbon solvents, ester solvents, ether solvents or mixtures thereof. In order to prevent uniform coating film hardening and roll mark defect, an ester solvent and an ether solvent may be appropriately selected and used for possible hydrocarbon solvents or workability and storage properties.

The solvent is preferably used about 50 to 150 parts by weight based on 100 parts by weight of the binder resin, but is not limited thereto.

<Additive>

In addition to the above components, the coating composition for pre-coating of the present invention may further contain any additives added to the paint, such as a curing accelerator, a surface conditioner, a viscosity control agent, a thickener, an antioxidant, a sunscreen, an antifoaming agent, and the like. These additives may be added to the composition in amounts known in the art. In addition, if necessary, other kinds of pigments may be further included in addition to the magnetic pigments used.

In particular, the present invention may further include a curing accelerator to promote the curing of the binder resin and the curing agent to improve the density of the coating film. As the curing accelerator, an acid catalyst, an amine catalyst or both may be used. In the case of curing, it is appropriate to use both an acid catalyst and an amine catalyst in order to cause a difference in curing between the inside and the surface of the coating film. More preferably, an amine catalyst having a higher volatility than the acid catalyst used is used. It is desirable to.

The acid catalyst may be a sulfonic acid shielded with an organic resin, but is not limited thereto. Non-limiting examples of the sulfonic acid include dinonyl naphthalene disulfonic acid, dinonyl naphthalene sulfonic acid, dodecyl benzene sulfonic acid, paratoluene sulfonic acid and the like. Preferred are dinonyl naphthalene sulfonic acid, paratoluene sulfonic acid and the like.

The acid catalyst is preferably shielded with a material that can be dissociated by heat. An organic resin may be used as the shielding material. Examples of the organic resins are amine compounds. In general, the amine compound is a primary amine (R-NH ₂ ), secondary amine (R ¹ -NH-R ² ), tertiary amine (R ¹ , R ² , depending on the number of hydrogen atoms in the ammonia is substituted with a hydrocarbon group , R ³ -N). At this time, when all hydrocarbon groups are alkyl groups, it is an aliphatic amine, and when one or more of a hydrocarbon group is an aryl group, it is called aromatic amine. Therefore, in the present invention, sulfonic acid shielded with an amine compound such as amine neutralized dodecylbenzenesulfonic acid may be used as a curing accelerator.

In addition, the amine catalyst can be used without limitation, conventional amine catalyst known in the art. Non-limiting examples of amine catalysts usable in the present invention include diethylamine, diisopropylamine, diisoflopanolamine, di-n-propylamine, di-n-butylamine, diisobutylamine, di -Secondary-butylamine, diallylamine, N-ethyl-1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-piecoline, 3-pie Choline, 4-piecoline or morpholine. These amine catalysts may be used alone or in combination with the aforementioned acid catalysts as curing accelerators.

Such a curing accelerator may be included in about 1 to 5 parts by weight based on 100 parts by weight of the binder resin. If the content of the curing accelerator is too small, curing of the coating film is insufficient depending on the working conditions, so that the physical properties of the coating film cannot be maintained. If the content is too large, the coating film hardens too hard to pop in the coating film during painting. popping) or contraction of the coating film may occur.

Coating compositions for pre-coating composed of such components can be prepared by conventional methods known in the art. For example, the coating composition for pre-coating comprises: mixing a binder resin, a curing agent, and a curing accelerator with a solvent to form a first mixture; Mixing the magnetic pigment into a solvent to form a second mixture; And after mixing the first mixture and the second mixture may be prepared by a manufacturing method comprising the step of forming a third mixture by stirring.

<Color mention>

The color substrate of the present invention comprises (a) a substrate; And (b) a coating film layer formed by applying the above-described precoating coating composition to one or both surfaces of the substrate and passing through the magnetic field and curing. Predetermined color or pattern is formed in the coating layer of this color base material by the magnetic pigment whose arrangement was adjusted according to the magnetic force.

The substrate may be a tile, a metal, a ceramic, a building interior material and / or a building exterior material, and specific examples thereof may be a hot dip galvanized steel sheet, an alloyed hot dip galvanized steel sheet, an electro galvanized steel sheet, or a hot dip aluminum-zinc alloy plated. Steel sheet, cold rolled steel, zinc hot dipping steel, electro-zinc steel, alloy-plate steel, copper sheet, tin-plate steel or aluminum sheet, wood and the like. However, this is not limitative.

In addition, the thickness of the coating layer may have a base coating thickness of about 5 to 10 μm, and the dry coating thickness may be about 5 to 25 μm. When the thickness is out of the above range, insufficient color development or pattern formation may occur on the surface of the substrate, or boiling may occur due to heat of the coating film surface. However, at the time of clear coating, it is preferable that the dry film thickness is about 1-15 micrometers.

The color substrate of the present invention can be prepared according to a conventional method, except for passing through a magnetic field before curing using a coating composition for precoating comprising a magnetic pigment, as shown in FIG. 2.

In the manufacturing method of the said color base material, For example, (a) apply | coating a base coating composition on a base material, and then first drying; (b) applying the aforementioned coating composition for pre-coating on the formed base coating film; And (c) passing the substrate on which the coating film is formed through a magnetic field and then drying it secondly. The color substrate produced by this method is different from the conventional color substrates in which a pattern is formed by forming a predetermined color or pattern by repeatedly using ink after curing of the coating film formed on the surface of the substrate. Various colors or patterns may be formed by only using the above-described coating composition for pre-coating and passing through a magnetic field without use. Therefore, the color base material of this invention which does not use ink separately can form the coating layer excellent in mechanical properties.

The base coating composition may be prepared by a method known in the art, for example, a method of mixing or dispersing the components of the paint by SG mill, kneader, roll, and the like. The base coating composition may be dried at room temperature or by heat drying, and there is no particular limitation as long as curing occurs. For example, heat drying may be performed at a temperature of about 200 to 220 ° C.

In addition, as a coating method of the coating composition for pre-coating, a conventional coating method known in the art is applicable. For example, roll coating, curtain flow coating, electrostatic powder and the like.

The base material to which the coating composition for pre-coating mentioned above was apply | coated by this method passes between magnetic fields before hardening. As the substrate coated with the coating composition for precoating passes through the magnetic field, the magnetic pigment in the coating composition for precoating is arranged at a specific position and angle by the magnetic force in the magnetic field. By changing the arrangement of the magnetic pigments, the amount of light absorbed by the magnetic pigments is changed or the angle of the reflected light is also changed. In this manner, various colors or patterns can be formed. Thus, the color substrate of the present invention can easily implement a variety of patterns by forming a variety of colors or patterns on the surface by a simple process of passing the magnetic field.

At this time, the substrate coated with the above-described coating composition for pre-coating passes between the magnetic fields at a speed of about 20 to 200 mpm (meter per minute). If the magnetic field passing speed of the substrate is less than 20 mpm, even if the arrangement of the magnetic pigment is controlled in the front part of the magnetic field, the arrangement of the magnetic pigment is returned to the original arrangement or at a different angle due to the influence of the magnetic field under different conditions during the movement of the substrate. It may be arranged that the desired color or pattern may not be formed or may not be obvious even if formed. In addition, when the magnetic field passing rate of the substrate is more than 200 mpm, the substrate passes through the magnetic field before the magnetic pigment is arranged at a specific angle by the magnetic force in the magnetic field, so that the desired color or pattern is not formed, and even if the color or pattern is It may not be obvious if it is formed.

In addition, the strength of the magnetic field can be adjusted according to the pattern formed on the color base material, preferably about 1000 mT to 1500 mT. If the strength of the magnetic field is too weak, the magnetic pigment may not be affected by the magnetic force, thereby forming a desired color or pattern. In addition, when the strength of the magnetic field is too strong, the substrate is stuck to the magnet, and thus the operation is not easy, and the arrangement of the magnetic pigments may be changed by the magnet having a different color or pattern, which may be blurred, and the color or pattern may be blurred.

After this magnetic field passing process, the substrate having a pattern is secondarily dried to cause curing. The secondary drying temperature is not particularly limited, but is preferably dried at room temperature or about 200 to 260 ℃. At this time, the drying time may be about 20 to 50 seconds.

Preferred examples of the color substrate produced by the above-described manufacturing method is Pre-Coating Metal (PCM).

Hereinafter, the present invention will be described in more detail. These examples are only for illustrating the present invention in more detail, it is apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

Example 1

1-1. Preparation of paint composition for precoating

Prepared polyester resin (Mw = 2,500 ~ 6,000) 36 parts by weight, melamine resin 8 parts by weight, acid catalyst (Nacure 1953 or 1419) 1 part by weight and solvents (XYLENE, SOLVESSO 100, SOLVESSO 150, DBE, PMA) 38 Parts by weight were added and mixed. Thereafter, the mixture and a mixture in which 7 parts by weight of plate-shaped carbonyl iron were uniformly dispersed in 10 parts by weight of a solvent were mixed with each other to obtain a coating composition for precoating.

1-2. Manufacture of prepainted steel sheet

The precoated coating composition of Example 1-1 was coated on the undercoated steel sheet so as to have a dry coating thickness of 5 to 20 µm. Thereafter, the coated steel sheet is passed through a magnetic field applied by a magnetic force of 1000 to 1500 mT generated by a magnet to form a pattern, and then heated and dried in an oven capable of raising the temperature of the steel sheet at room temperature to 224 ° C. in 24 seconds to color the steel sheet. Was prepared.

Example 2

2-1. Preparation of paint composition for precoating

32 parts by weight of the prepared polyester resin (Mw = 7,000 to 9,000), 5 parts by weight of melamine resin, 2 parts by weight of an acid catalyst (Nacure 1953 or 1419) and a solvent (XYLENE, SOLVESSO 100, SOLVESSO 150, DBE, PMA) 44 Parts by weight were added and mixed. Thereafter, the mixture and a mixture in which 7 parts by weight of plate-shaped carbonyl iron were uniformly dispersed in 10 parts by weight of a solvent were mixed with each other to obtain a coating composition for precoating.

2-2. Manufacture of prepainted steel sheet

The coating composition for pre-coating of Example 2-1 is applied to a steel plate coated with a coating so as to have a dry coating thickness of 5 to 20 μm, and dried in an oven capable of raising the temperature of the steel plate at room temperature to 232 ° C. in 35 seconds. A color steel sheet was manufactured in the same manner as in Example 1-2 except for the above.

Example 3

3-1. Preparation of paint composition for precoating

33 parts by weight of the prepared polyester resin (Mw = 10,000-20,000), 8 parts by weight of melamine resin, 2 parts by weight of an acid catalyst (Nacure 1953 or 1419) and a solvent (XYLENE, SOLVESSO 100, SOLVESSO 150, DBE, PMA) 40 Parts by weight were added and mixed. Thereafter, the mixture and a mixture in which 7 parts by weight of plate-shaped carbonyl iron were uniformly dispersed in 10 parts by weight of a solvent were mixed with each other to obtain a coating composition for precoating.

3-2. Manufacture of prepainted steel sheet

The coating composition for pre-coating of Example 3-1 is applied to a steel plate coated with a coating so that the dry coating thickness is 5 to 20 μm, and dried in an oven capable of raising the temperature of the steel plate at room temperature to 232 ° C. in 35 seconds. A color steel sheet was manufactured in the same manner as in Example 1-2 except for the above.

Example 4

4-1. Preparation of paint composition for precoating

9 parts by weight of melamine resin, 1.5 parts by weight of urea resin and 45.5 parts by weight of solvent were added to 26 parts by weight of the prepared epoxy resin (Mw = 4,000 to 5,000) and mixed. Thereafter, the mixture and a mixture in which 8 parts by weight of plate-shaped carbonyl iron were uniformly dispersed in 10 parts by weight of a solvent were mixed with each other to obtain a coating composition for precoating.

4-2. Manufacture of prepainted steel sheet

The coating composition for pre-coating of Example 4-1 is applied to the pretreated steel sheet so as to have a dry coating thickness of 5 to 10 μm, and dried in an oven capable of raising the temperature of the steel sheet at room temperature to 216 ° C. in 24 seconds. A color steel sheet was manufactured in the same manner as in Example 1-2.

Example 5

5-1. Preparation of paint composition for precoating

10 parts by weight of the melamine resin, 1.5 parts by weight of the acid catalyst and 39.5 parts by weight of the solvent were added and mixed to 42 parts by weight of the prepared polyester resin (Mw = 6,000 to 7,000). Thereafter, the mixture and a mixture in which 3 parts by weight of plate-shaped carbonyl iron were uniformly dispersed in 4 parts by weight of a solvent were mixed with each other to obtain a coating composition for precoating.

5-2. Manufacture of prepainted steel sheet

The coating composition for pre-coating of Example 5-1 is applied to a top coat-coated steel sheet so as to have a dry coating thickness of 5 to 15 μm, and dried in an oven capable of raising the temperature of the steel sheet at room temperature to 232 ° C. in 30 seconds. A color steel sheet was manufactured in the same manner as in Example 1-2 except for the above.

Comparative Example 1

1-1. Preparation of paint composition for precoating

32 parts by weight of the prepared polyester resin (Mw = 7,000 to 9,000), 5 parts by weight of melamine resin (CYMEL 303), 1.5 parts by weight of an acid catalyst (Nacure 1953 or 1419) and a solvent (XYLENE, SOLVESSO 100, SOLVESSO 150, DBE) , PMA, BUTANOL) 36 parts by weight was added and mixed. Thereafter, the mixture and the mixture in which 8 parts by weight of the pigment were uniformly dispersed in 13 parts by weight of the solvent were mixed with each other to obtain a coating composition for precoating.

1-2. Manufacture of prepainted steel sheet

After coating the coating composition for pre-coating of Comparative Example 1-1 so that the dry coating thickness is 5 to 20 μm, the oven is painted for 35 seconds at RT (RETENTION TIME) and PMT (PEAK METAL TEMPERATURE) at 224 ° C. It was dried by heating to prepare a color steel sheet.

1-3. Color or pattern formation

Ink was repeatedly transferred to the surface of the colored steel sheet prepared above using a gravure roll to form a color or a pattern.

Experimental Example  1. Degree of pattern formation and concealment according to coating thickness

The relationship between the pattern formation degree, the degree of concealment, and the coating film thickness of the color coating film formed using the coating composition for precoating of this invention was evaluated.

In the case of the color steel sheets prepared in Examples 1 to 5, the thicknesses of the coating films formed on the base coated steel sheets were adjusted to 4 μm, 9 μm, 16 μm, and 23 μm, respectively, and the degree of pattern formation and the degree of concealment were measured. , The results are shown in Table 1 below.

As a result of the experiment, all of the colored steel sheets produced in Examples 1 to 5 had a cloudy pattern formed when the thickness of the coating film was about 4 μm, and the hiding power was also insufficient.

Specifically, it was confirmed that the colored steel sheets prepared in Examples 1 to 3, that is, the colored steel sheets formed on the undercoated steel sheets, were well patterned and the degree of concealment was improved as the thickness of the coating film was increased. Particularly, when the thickness of the coating film was about 23 μm, the pattern was well formed three-dimensionally, and it was confirmed that the hiding power was also good.

In addition, it was confirmed that the color steel sheet produced in Example 4, that is, the color steel sheet formed on the pretreated steel sheet, had a good pattern formation degree and a degree of concealment when the thickness of the coating film was about 9 µm. However, when the thickness of the coating film is 16 µm or more, the coating film boiling phenomenon occurred.

In addition, the color steel sheet manufactured in Example 5, that is, the color steel sheet formed on the top coat steel sheet was formed with a good pattern as the thickness of the coating film increases, but when the coating film thickness is 16 ㎛, the color is excessive due to excessive concealment Could be confirmed.

Thus, when manufacturing a color steel sheet using the coating composition for pre-coating of the present invention, it can be confirmed that the degree of pattern formation and concealment is improved as the coating film thickness increases. However, it can be seen that the thickness of the coating film is appropriate to adjust the thickness of the coating film depending on whether the coating composition for pre-coating is used, that is, undercoat, top coat or intermediate coating.

Experimental Example  2. Pattern formation according to the magnetic field passing speed of the substrate

In the production of the color steel sheet using the coating composition for precoating of the present invention, the relationship between the magnetic field passing rate and the pattern formation of the substrate coated with the coating composition for precoating was measured.

After adjusting the rate of passage of the steel sheet coated with the coating composition for precoating of Examples 1 to 5 to 15 mpm, 100 mpm, and 200 mpm, respectively, the pattern formation of the coating was measured, and the results are shown in Table 2 below. And shown in FIG. 3.

As can be seen in Figure 3, when the magnetic field passing rate of the steel sheet 100 mpm it was confirmed that the pattern is formed clearly. On the other hand, when the magnetic field passing speed of the steel sheet is 15 mpm or 200 mpm, the pattern is blurred or undesired lines are formed. Especially, when the magnetic field passing speed of the steel sheet is 200 mpm, the pattern is almost unaffected by the magnet. Did.

Thus, when manufacturing a color steel sheet using the coating composition for pre-coating of the present invention, it was confirmed that the steel sheet coated with the composition is appropriate to pass through the magnetic field at a speed of about 20 ~ 200 mpm.

Experimental Example  3. Property test evaluation

The physical property evaluation of the coating film formed using the coating composition for precoats of Examples 1-5 and Comparative Example 1 was performed based on the following test method. The results of each experiment are shown in Table 3.

<Thickness>

The thickness of the coating film formed on the base coating film was measured, respectively.

<Glossy>

60 ° mirror reflection value was measured and evaluated using the gloss machine of BYK or SHEEN. At this time, the workability was good matte (12%), but can be used as needed, glossy.

<Appearance>

It evaluated about the pattern formation on the coating film surface.

<Adhesiveness>

100 grids were made by using a sharp knife on the dried film according to ASTM D3359 TEST METHOD B, and then squeezed vertically and horizontally at 1 mm intervals.Then, the cellophane tape was rubbed and rubbed. It is to evaluate whether or not peeling off. At this time, it evaluated in six steps according to the peeling degree of a coating film.

5B: no coating film peeling at all, 4B: less than 5% coating film peeling,

3B: 5-15% peeling of coating film, 2B: 15-35% peeling of coating film,

1B: 35 to 65% of the film peeling, 0B: 65% or more of the film peeling

<Pencil hardness>

The degree of scratching of the coating film was evaluated by applying a load of 1 kg at 45 ° according to the type of pencil (B, HB, F, H, 2H, 3H, 4H, etc.) according to the pencil hardness method of JIS K-5400. . Here, the maximum strength when no scratch was generated in the coating film was denoted by pencil hardness, and when the test was repeated five times on one sample and no trace was generated three times or more, the hardness of the pencil of the sample was indicated. At this time, as the degree of scratching, (Soft) B → HB → F → H → 2H → 3H → 4H → F (Hard) in order, that is, it is displayed in pencil type at the maximum strength.

<Impact>

A Dupont type impact tester is used to drop the coating film with a weight of 500 g (diameter: 1/2 inch) at a height of 30 cm and then visually evaluate the peeling of the coating film. At this time, if a coating film does not peel, it is favorable, and when a coating film peels, it is set as defect.

<M.E.K. RUBBING>

M.E.K. was immersed in GAUZE, and a reciprocating rubbing test was performed in a straight line with a load of 2 kg on the dried coating film. The number of round trips when the paint surface was peeled off during rubbing is shown in Table 3 below. However, peeling off at both ends 1cm is to be ignored at this time.

<Flexibility>

After coating the coated specimen at 180 ° using VICE, the cracks and peeling state of the coated film on the processed surface were visually evaluated.

For reference, the numbers in Table 3 are expressed in the order of (excellent) 5 points> 4 points> 3 points> 2 points> 1 point (bad). In addition, the raw material steel plate to which a coating composition is apply | coated used the pretreated GI or EGI steel plate.

As a result of the experiment, the coating film formed using the coating composition for precoating of the present invention showed excellent physical properties in all evaluation test items.

1 is a photograph of a color substrate prepared using the coating composition for pre-coating of the present invention, (a) is a photograph of the surface of the substrate before passing through the magnetic field, and (b) is a photograph of the surface of the substrate after passing through the magnetic field.

Figure 2 shows a flow chart of a process for producing a color substrate using the coating composition for pre-coating of the present invention.

Figure 3 is a photograph showing whether the pattern formed according to the magnetic field passing rate of the substrate to which the coating composition for pre-coating of the present invention is applied, (a) is the magnetic field passing rate of the substrate is 15 mpm, (b) is the When the magnetic field passage speed is 100 mpm, (c) is a photograph showing a pattern formed on the surface of the substrate when the magnetic field passage speed of the substrate is 200 mpm.

Claims (9)

A pre-ating coating composition comprising a binder resin, a curing agent, a solvent, and an additive, The arrangement is adjusted according to the magnitude or direction of the magnetic force to form a magnetic pigment (magnetic pigment) to form a predetermined color or pattern in the range of 5 to 50 parts by weight based on 100 parts by weight of the binder resin and the coating composition for precoating A coating composition for a single coating type pre-coating, characterized in that the coated substrate can pass through the applied magnetic field to form a three-dimensional coating film. The single coating type pre-coating according to claim 1, wherein the magnetic pigment has one or more specific shapes selected from the group consisting of spherical, tube, fiber, rod, and plate shapes. Paint composition for use. The coating composition of claim 1, wherein the magnetic pigment is selected from the group consisting of a pigment containing an iron component, a pigment containing a nickel component, and a pigment containing a cobalt component. The coating composition for a single coating type pre-coating according to claim 1, wherein the magnetic pigment has an average particle diameter of 10 to 40 µm. delete The method of claim 1, wherein the binder resin is a single coating type, characterized in that selected from the group consisting of polyester resins, acrylic resins, epoxy resins and mixtures thereof Coating composition for pre-coating. According to claim 1, wherein the curing agent is a single coating type, characterized in that selected from the group consisting of melamine resin, urethane, urea resin and mixtures thereof Coating composition for pre-coating. The coating composition of claim 1, wherein the additive comprises a curing accelerator, and further comprises an acid catalyst, an amine catalyst, or both as the curing accelerator. The coating composition for single coating type pre-coating according to claim 1, which is a coating composition for color steel sheets.

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