KR101536448B1 - Resin Composition For Coating Steel Sheet With Improved Printability, Coated Steel Sheet Using The Same And Method For Manufacturing Thereof - Google Patents

Abstract

The present invention relates to a resin composition for coating a steel sheet, which comprises a cellulose fiber having an L / D (length / thickness) ratio of 5 to 1000 fibers in an amount of 0.3 to 10 parts by weight based on 100 parts by weight of the main resin. The present invention also relates to a surface-treated steel sheet coated with the resin composition and having excellent printability, and a method for producing the same.
According to the present invention, since the ink is more easily absorbed through the microstructure of the cellulose-based fibers contained in the resin composition, the printing properties of the steel sheet coating layer can be improved and a surface-treated steel sheet excellent in workability and workability can be produced .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a resin composition for steel sheet coating having excellent printability, a surface-treated steel sheet using the same,

The present invention relates to a resin composition for coating a steel sheet with improved water absorbability to ink and a method for producing the same. Further, the present invention relates to a surface-treated steel sheet on which a coating layer containing the resin composition is formed, and a method for producing the same.

In recent years, in accordance with the needs of consumers, a printed steel sheet having a beautiful appearance and a texture is emerging as a result of forming a pattern layer using ink together with a color steel plate painted with a single color. The color steel sheet and the printing steel sheet having excellent visual appearance of the surface appearance are widely applied to the fire door, the elevator interior, the high-grade building, the interior decoration, the household appliance, the kitchen and the furniture in accordance with the individualization and the high quality.

However, in general, the wettability of the printing ink is lowered on the metal plate or the polymer resin layer, and the absorptivity of the ink of the adherend is insufficient, so that the printing layer is easily peeled off or it is difficult to realize a high resolution of the pattern to be printed. Therefore, a very complicated technique is required when the steel sheet is colored or various patterns and pictures are drawn.

As a conventional technique for improving the water absorption of a metal plate, Japanese Laid-Open Patent Publication No. 2001-105529 discloses a technique of covering a metal plate with a resin layer and forming an inorganic ink absorbing layer on the resin layer. The above Patent Document includes porous inorganic particles having an average particle size of 1-10 mu m and a resin having a water-soluble resin or a hydroxyl group as an ink receiver, thereby improving the adhesion and coloring property of the ink-absorbing layer.

However, when a porous inorganic particle is used, capillary phenomenon and the like are used to ensure printability. However, when a large amount of inorganic particles are included, the coating film is brittle, so that there is a problem in workability and the like do. In addition, there is a limitation in that printing properties can be improved only when the porous particles are arranged in a direction coinciding with the printing direction.

Unlike the conventional technique using porous inorganic particles, it is desired to provide a steel sheet coating resin composition containing cellulose fibers on the surface of a steel sheet and a steel sheet having a coating layer (ink absorbing layer) formed thereon. Accordingly, it is an object of the present invention to provide a surface-treated steel sheet which exhibits high resolution and processability by inducing absorption of ink into fine spaces of fibers, and a method for producing the same.

The present inventors have found that the printing layer including the conventional porous inorganic particles can secure the printing property but the printing layer can become bulky due to the difficulty in control such as adjustment and arrangement of the particles, . As a result, efforts have been made to improve the printing properties of the steel sheet without using the conventional inorganic particles. When the surface of the cellulose-based fiber is treated with the silane compound and then mixed with the main resin and treated on the surface of the steel sheet, And completed the present invention.

An embodiment of the present invention is a resin composition for coating a steel sheet, which comprises a cellulose fiber having an L / D (length / thickness) ratio of 5 to 1000 fibers in an amount of 0.3 to 10 parts by weight based on 100 parts by weight of the main resin.

The fiber L / D ratio and content preferably satisfy the following formula (1).

3 <{(fiber L / D) x content of fiber} <50 (One)

The main resin may be at least one selected from the group consisting of a polyester resin, an epoxy resin, an acrylic resin, a urethane resin and an alkyd resin,

The cellulosic fibers may be at least one selected from the group consisting of cotton, viscose rayon, polynosic rayon, cubula, acetate and lyocell.

The resin composition may further comprise 0.01 to 2 parts by weight of a silane compound per 100 parts by weight of the main resin,

Wherein the silane compound is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-trimethoxysilylpropyl methacrylate, 3-aminopropyltrimethoxysilane and mercapto- Lt; / RTI &gt;

Further, the resin composition may be coated on the surface of the steel sheet for inkjet printing.

Still another embodiment of the present invention is a steel plate comprising: a steel plate; A surface-treated steel sheet excellent in printability, in which a coating layer containing 0.3 to 10 parts by weight of cellulose-based fibers having a L / D ratio (length / thickness) of 5 to 1000 fibers on at least one surface of the steel sheet, to be.

The thickness of the coating layer and the content of the fibers preferably satisfy the following formulas (1) and (2).

3 < {(fiber L / D) x content of fiber} < 500 (One)

1? {(Fiber L / D) / thickness of coating layer}? 200 ... (2)

The coating layer may further comprise 0.01 to 2 parts by weight of a silane compound per 100 parts by weight of the main resin,

Preferably, the coating layer further comprises a print layer on top.

Since the coating layer contains the cellulose-based fiber excellent in absorption, the absorption power against the ink can be remarkably improved as compared with a normal coating layer made of only a resin.

In addition, unlike the coating layer comprising the porous inorganic particles described above, the coating phenomenon does not occur in the coating film, thereby facilitating the processing.

Further, by controlling the L / D value, the thickness and the content of the fiber, it is possible to propose a manufacturing condition of a steel sheet excellent in workability and workability.

According to one aspect of the present invention, there is provided a resin composition for coating a steel plate, which comprises 0.3 to 10 parts by weight of cellulose-based fibers having an L / D (length / thickness) ratio of 5 to 1000 in relation to 100 parts by weight of a main resin . The resin composition is more preferably coated on the surface of the steel sheet for inkjet printing. When the content of the cellulose-based fibers is less than 0.3 part by weight with respect to 100 parts by weight of the main resin, the printing property (ink absorbency) of the coating layer including the resin becomes poor If the amount is more than 10 parts by weight, the coating workability is lowered due to entanglement of the fibers.

When the resin composition contains the cellulose fibers, the ink can be easily absorbed between the microstructures of the fibers. That is, a large amount of hydroxyl groups (OH groups) existing in the cellulose-based fibers easily bonds with the ink molecules, thereby increasing the adhesion to the ink as well as the ink, thereby achieving high resolution in printing.

If the ratio of the fiber L / D (length / thickness) is less than 5, the workability of the steel sheet coated with the composition is deteriorated. If the ratio exceeds 1000, the fibers may become entangled and the coating operation itself may become impossible. At this time, the ratio of L / D (length / thickness) of the fibers is not limited thereto, but may be more preferably 100 to 700. As the value of the fiber L / D becomes relatively large, the toughness becomes better and the phenomenon of the coating layer brink may disappear.

At this time, the content of the fiber L / D preferably satisfies the following formula (1).

3 < {(fiber L / D) x content of fiber} < 500 (One)

When the content of the {(fiber L / D) x fiber} is less than 3, the fiber L / D value and content are both low, resulting in a bleaching of the film and poor workability. Can be significantly reduced.

According to a preferred embodiment of the present invention, the main resin may be at least one selected from the group consisting of a polyester resin, an epoxy resin, an acrylic resin, a urethane resin and an alkyd resin, Is not particularly limited as long as it is capable of dispersing and coating the coating film.

According to a preferred embodiment of the present invention, the cellulosic fibers may be at least one selected from the group consisting of cotton, viscose rayon, polynosic rayon, cubula, acetate and lyocell.

According to a preferred embodiment of the present invention, the resin composition may further comprise 0.01 to 2 parts by weight of a silane compound based on 100 parts by weight of the main resin. The silane compound may be coupled with the cellulose-based fiber to improve the surface wettability of the cellulose-based fiber to the main resin. If the silane compound is used in an amount of less than 0.01 part by weight, the effect of the addition of the silane compound is insufficient because the fibers are not sufficiently treated. If the amount exceeds 2 parts by weight, the silane compound remains in the coating, A phenomenon may occur, which may cause problems in storage stability.

According to a preferred embodiment of the present invention, the silane compound is selected from the group consisting of 3-aminopropyltriethoxysilane, 3-trimethoxysilylpropyl methacrylate, 3-aminopropyltrimethoxysilane and mercapto- &Lt; / RTI &gt;

The coupling reaction between the silane compound and the cellulose-based fiber can be performed separately before mixing with the main resin. In this case, it is preferable that the silane compound is mixed with alcohol or water, and the fiber is immersed for 30 minutes to one day. When the reaction is completed, it is preferable to remove water or alcohol and dry it. On the other hand, when the reaction is induced while stirring with the main resin, it is preferable to stir at a speed of 200 to 1000 rpm for 30 minutes to 1 day.

In addition, the resin composition may further include a curing catalyst. However, the curing catalyst may be dodecylbenzene sulfonic acid.

According to still another aspect of the present invention, A surface-treated steel sheet excellent in printability, in which a coating layer containing 0.3 to 10 parts by weight of cellulose-based fibers having a L / D ratio (length / thickness) of 5 to 1000 fibers on at least one surface of the steel sheet, Can be provided.

The steel sheet is not particularly limited, and for example, a metal sheet such as an iron sheet or an aluminum sheet, preferably a cold rolled steel sheet; galvanized steel; Zinc-plated steel sheets such as zinc-nickel-plated steel sheet, zinc-iron-plated steel sheet, zinc-titanium-coated steel sheet, zinc-magnesium-coated steel sheet, zinc manganese-coated steel sheet, zinc-aluminum-coated steel sheet and zinc- Aluminum-based galvanized steel; A plated steel sheet containing at least one selected from the group consisting of cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron, magnesium, tin and copper as a dissimilar metal or an impurity; A coated steel sheet in which at least one kind of inorganic material selected from the group consisting of silica and alumina is dispersed in the plating layer; An aluminum alloy plate to which at least one kind selected from the group consisting of silicon, copper, magnesium, iron, manganese, titanium, and zinc is added; Or zinc phosphate coated with phosphate; Or a hot-rolled steel sheet may be used. If necessary, a multi-layered plated metal sheet which has been treated with two or more kinds of platings sequentially may be used.

Also, the thickness of the coating layer may be 5 to 20 占 퐉, though it is not limited thereto. When the thickness is less than 5 mu m, uniform coating may be difficult, and when the thickness is more than 20 mu m, the thickness is relatively thick and the workability of the steel sheet is deteriorated.

Further, it is preferable that the thickness of the coating layer and the fiber content of the fiber satisfy the following formulas (1) and (2) within the fiber L / D ratio range as described above.

3 < {(fiber L / D) x content of fiber} < 500 (One)

1? {(Fiber L / D) / thickness of coating layer}? 200 ... (2)

When the content of {(fiber L / D) x fiber content} is 3 or less, the workability is poor, and when it is 500 or more, the coating workability may be significantly lowered. Further, even if the fiber L / D ratio satisfies the range of 5 to 1000, since the fiber L / D value is smaller than the thickness ({(fiber L / D) / thickness of the coating layer} It is bad. Also, if {(fiber L / D) / thickness of the coating layer} within the range of the L / D value is more than 200, the coating layer should be formed to less than 5 탆, however, the thinner the coating layer, the poorer the workability.

Therefore, if the content of the {(fiber L / D) x fiber} and {(fiber L / D) / thickness of the coating layer} satisfy the above-described range under the condition that the fiber L / D is 5 to 1000, The forming work is facilitated, and the workability of the formed steel sheet can be secured. For example, when the fiber L / D is 1000, the thickness of the coating layer should be larger than 5 탆. In this case, the fiber content is preferably 0.3 or more and less than 0.5 in consideration of printability.

According to a preferred embodiment of the present invention, the coating layer may further comprise 0.01 to 2 parts by weight of a silane compound per 100 parts by weight of the main resin, and the silane compound may preferably cause a coupling reaction with the cellulose fiber.

According to a preferred embodiment of the present invention, the coating layer may further include a printing layer on the upper side, and more preferably, an ink-jet printing layer. Since the coating layer includes cellulose fibers, absorption and adsorption of the printing layer formed on the upper layer can be further improved. At this time, the method of manufacturing the steel sheet includes forming a coating layer; Drying the coating layer; And printing at least one of a character, a pattern, a shape, or a combination thereof with an inkjet print on one surface of a steel sheet on which a coating layer is formed.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

The components used in this example were as follows.

- Base resin: polyester resin having a molecular weight of 10000 to 12000

- Cellulose fiber: Viscose rayon

- Silane compound: 3-aminopropyltriethoxysilane

- Curing catalyst: Dodecylbenzenesulfonic acid

The method applied in this embodiment was as follows.

The weight of the fibers is set to 0.1, 0.3, 0.5, 1, 3, 5, and 5, respectively, based on 100 weight parts of the main resin using cellulose fibers having a fiber L / D (length / thickness) ratio of 1, 10 parts by weight. At this time, the weight of the fibers was limited to 10 parts by weight in order to prevent excessive entanglement. Subsequently, the prepared fiber was sufficiently stirred at 1000 rpm so as to be uniformly dispersed in the resin. Thereafter, 1 part by weight of a silane compound and 0.1 part by weight of a curing catalyst were added based on 100 parts by weight of a main resin to prepare a coating composition for forming a printing layer .

First, the prepared coating composition was coated on steel plates of 150 X 75 mm in thickness of 5, 10 and 20 탆, respectively, and dried to prepare test pieces. The printability (ink absorption and adhesion) was evaluated in the following manner. Several data that can compare the printability are extracted and shown in Table 1 below. At this time, as the thickness of the coating layer is usually thicker, the workability is lowered.

- Printing property: Each steel sheet coated with the coating composition was printed with a pattern using an inkjet print. Then, 100 chambers (10 x 10) were formed at intervals of 1 mm in the printing area, and it was confirmed whether or not the ink was peeled off after the adhesive tape (CT-24,

Fiber L / D ^{1 )} Coating thickness
(탆) Fiber content
(Parts by weight) (Fiber L / D) / coating thickness (Fiber L / D) x fiber content Printability One 5 0.1 0.2 0.1 Bad One 5 0.3 0.2 0.3 usually One 5 0.5 0.2 0.5 Good 10 5 0.1 2 One Bad 10 5 0.3 2 3 usually 10 5 0.5 2 5 Good 10 10 0.5 One 5 Good 100 5 0.1 20 10 Bad 100 5 0.3 20 30 usually 100 5 0.5 20 50 Good 100 10 0.1 10 10 Bad 100 10 0.3 10 30 usually 100 10 0.5 10 50 Good 100 20 0.1 5 10 Bad 100 20 0.3 5 30 usually 100 20 0.5 5 50 Good 1000 5 0.1 200 100 Bad 1000 5 0.3 200 300 Good 1000 10 0.1 100 100 Bad 1000 10 0.3 100 300 Good 1000 20 0.1 50 100 Bad 1000 20 0.3 50 300 Good

1) Fiber L / D = fiber length / fiber thickness

As can be seen from the above Table 1, when the fiber content is less than 0.3 compared to 100 parts by weight of the resin, the dyeability is very poor. That is, when the content of the fibers contained in the printed layer of the steel sheet on which the print layer is formed is less than 0.3, it is judged that the effect by the addition of fibers is not obtained and is poor. The following Condition 1 can be derived.

Condition 1) 0.3? Subject resin 100 parts by weight Fiber content? 10

Then, the bending workability and workability were examined by the following methods, and the bending workability and workability depending on the fiber L / D, the coating thickness and the fiber content were compared and analyzed as shown in Table 2 below.

- Flexural Workability: The coated specimens were bent 180 ° to form a 0t curved surface, and then the defects and goodness were evaluated according to the occurrence of cracks.

- Workability: In the roll coating operation, defects and goodness were evaluated by the occurrence of coating film defects.

Fiber L / D ^{1 )} Coating thickness
(탆) Fiber content
(Parts by weight) (Fiber L / D) / coating thickness (Fiber L / D) x fiber content Workability curve
Workability ^{2 )} One 5 0.3 0.2 0.3 Good Bad One 5 0.5 0.2 0.5 Good Bad One 5 One 0.2 One Good Bad 10 20 0.5 0.5 5 Good Bad 10 20 5 0.5 50 Good Bad 10 20 10 0.5 100 Good Bad 10 10 0.5 One 5 Good Good 10 5 0.3 2 3 Good Bad 10 10 0.3 One 3 Good Bad 10 5 One 2 10 Good Good 100 10 0.3 10 30 Good Good 100 5 0.5 20 50 Good Good 100 5 5 20 500 Bad - 100 5 10 20 1000 Bad - 1000 20 0.3 50 300 Good Good 1000 10 0.3 100 300 Good Good 1000 5 0.3 200 300 Good Good 1000 5 0.5 200 500 Bad - 1000 5 One 200 1000 Bad - 1000 5 3 200 3000 Bad -

1) Fiber L / D = fiber length / fiber thickness

2) If the workability is bad, it is impossible to form a coating layer and it is impossible to test.

As can be seen from the above Table 2, when the L / D value of the fiber was 1, all of the bending workability test results were cracked and the workability was remarkably decreased even though the coating thickness was 5 μm. When the fiber L / D was 1000, the maximum content of the fibers was only 0.3 part by weight. That is, when the L / D exceeds 1000, the fiber should be hardly added. In this case, since the printing property is deteriorated as shown in Table 1, it is understood that the appropriate level of L / D is preferably not more than 1,000.

On the other hand, when [(fiber L / D) / coating thickness] value was 1 or more, workability was good. That is, as the L / D value of the fiber per unit thickness increases, the toughness of the coating increases, so that the coating does not brittle and is resistant to a strong impact. As a result, it was found that as the L / D value of the fiber per thickness becomes larger, the workability becomes better. At this time, since the coating thickness considering the workability is 5 占 퐉 or more, it can be seen that the L / D value must be at least 5 in order to make the value of [(fiber L / D) / coating thickness] The following condition 2 was derived.

Condition 2) 5? Fiber L / D? 1000

Also, since the maximum value of the fiber L / D is 1000 and the minimum value considering the workability is 5 占 퐉, it is found that the optimum range of [(fiber L / D) / coating thickness]

Condition 3) 1? (Fiber L / D) / coating thickness? 200

Further, according to the results of Table 2, the flexural workability is poor when the value of [(fiber L / D) x fiber content] is less than 3, and when the value is more than 500, And the workability was very poor. That is, when the fibers having a relatively long length are present in a large amount, they tend to be entangled or pushed, resulting in poor workability. When the workability is low, evaluation of the bending workability itself can not be carried out. Thus, the following condition 4 can be derived.

Condition 4) 3 < (Fiber L / D) x Fiber Content < 500

As a result of synthesizing the above-mentioned conditions, it is preferable that the fiber is added in the range of 0.3 to 10 parts by weight per 100 parts by weight of the main resin in order to secure the printing property of the steel sheet. For the consistency and repetitive reproducibility of the work, the following fibers are used having an L / D of 5 or more and 1000 or less, wherein the value of [(fiber L / D) / coating thickness] ) x fiber content] should be controlled to be greater than 3 and less than 500 to control the fiber content and coating thickness.

Claims (11)

Wherein the ratio of the fiber L / D ratio and the content of the cellulose fiber is in the range of 5 to 1000 L / D (100 parts by weight) based on 100 parts by weight of the main resin, A resin composition for coating a steel sheet satisfactory.
3 < {(Fiber L / D) x fiber content} < 500 (1)
delete The resin composition according to claim 1, wherein the main resin is at least one selected from the group consisting of a polyester resin, an epoxy resin, an acrylic resin, a urethane resin and an alkyd resin.
The resin composition according to claim 1, wherein the cellulose-based fiber is at least one selected from the group consisting of cotton, viscose rayon, polynosic rayon, cubula, acetate and lyocell.
The resin composition for coating a steel sheet according to claim 1, wherein the resin composition further comprises 0.01 to 2 parts by weight of a silane compound per 100 parts by weight of the main resin.
The method of claim 5, wherein the silane compound comprises 3-aminopropyltriethoxysilane, 3-trimethoxysilylpropylmethacrylate, 3-aminopropyltrimethoxysilane, and mullcatopropyltrimethoxysilane. And at least one member selected from the group consisting of iron and iron.
The resin composition for coating a steel sheet according to claim 1, wherein the resin composition is coated on the surface of a steel sheet for ink jet printing.
Steel plate;
Wherein a coating layer containing 0.3 to 10 parts by weight of cellulose-based fibers having an L / D (length / thickness) ratio of fibers of 5 to 1000 to 100 parts by weight of the main resin is formed on at least one surface of the steel sheet,
Wherein the thickness of the coating layer and the content of the fiber satisfy the following formulas (1) and (2).
3 < {(Fiber L / D) x fiber content} < 500 (1)
1? (Fiber L / D) / thickness of coating layer}? 200 (2)
delete The surface-treated steel sheet according to claim 8, wherein the coating layer further comprises 0.01 to 2 parts by weight of a silane compound based on 100 parts by weight of the main resin.
The surface-treated steel sheet according to claim 8, wherein the coating layer further comprises a printing layer on the top.