KR20040026022A - A resin solution for resin coating steel sheets having excellent workability and quality of surface, and manufacturing method of resin coating steel sheets to use it - Google Patents

Abstract

PURPOSE: Provided are a resin solution for a resin coating steel plate excellent in roll coating ability and surface quality and a process for producing the resin coating steel plate by using the resin solution. CONSTITUTION: The resin solution contains 100pts.wt. of a water-soluble silicone resin as a main material resin, 2-10pts.wt. of nano silicate, 100-140pts.wt. of silica, 0.3-1.0pts.wt. of a silicone leveling agent. And the resin coating steel plate is produced by spreading the resin solution on a chromate-treated zinc alloy-plated steel plate and then baking the steel plate at 200-250deg.C, wherein the resin coating has a thickness of 0.5-3.0 micrometer.

Description

A resin solution for resin coating steel sheets having excellent workability and quality of surface, and manufacturing method of resin coating steel sheets to use it}

The present invention relates to a resin coating of a Shrinkage Band product used as a safety device among the internal components of a CRT for a TV or a monitor. More particularly, the present invention relates to a roll coating property in a continuous operation of coating a resin layer. It relates to a resin solution for improving the surface quality and a method for producing a resin coated steel sheet using the same.

Recently, the shrinky band band steel plate used in the CRT for TV and monitor uses an aluminum plated steel plate by hot dip plating, and is used as a safety device by fixing the upper part of the TV CRT in a band form. The TV or monitor CRT consists of a 5 ~ 10mm thick glass tube to maintain a high vacuum of about 10 ^-7 Torr. On the other hand, if a severe impact from the outside is applied to the CRT and the glass tube is broken, the glass may be scattered into pieces due to the internal vacuum, which may cause a large accident. In order to prevent this risk, it is configured to wrap the TV brown tube with a steel plate having a certain strength so that the glass fragments sink inside even if the glass tube is broken.

Glass tube fastening method in a conventional CRT tube is a CRT tube in a state in which the frame of the steel plate is rapidly heated to 500 to 600 ° C. within a few seconds by an electric resistance heating method by an electric resistance heating method. By mounting and cooling by air cooling (air cooling) is a method that is fixed to the CRT as the steel sheet shrinks. However, in the case of a general cold rolled steel sheet, even after being fastened to the CRT, corrosion is difficult, and thus it is difficult to use. In addition, when a pure galvanized steel sheet is applied, it is heated to a temperature relatively higher than the melting point of zinc when it is heated to a high temperature and thermally expanded so that zinc melts and flows to the glass of the CRT or damage to the CRT product appearance. Will occur. Therefore, galvalume plated steel sheets which are corrosion-resistant aluminum plated steel sheets and alloyed aluminum plated steel sheets are widely used.

The required physical properties of the shrinkage band steel sheet used in the CRT for TV and monitor can be largely divided into strength, weldability, flame resistance (no smoke), and corrosion resistance. First, a steel sheet having an appropriate level of tensile strength and thickness is required according to the CRT size. The larger the size of the CRT (the diagonal length of the CRT is usually called the size of the CRT), the thicker the steel sheet for the band should be in accordance with the vacuum degree of the CRT. On the contrary, the smaller the CRT, the thinner the steel sheet is required.

In addition, when welding the steel sheet, if the thickness of the resin layer is thick, not only welding is difficult, but also spatter is generated during welding, so that the surface quality of the band steel sheet is deteriorated.

When the steel sheet is heated to 500 ~ 600 ℃ PMT (Peak Metal Temperature) to cover the band steel plate on the CRT, the organic material on the surface is pyrolyzed to generate smoke. As a result, the environment of the CRT workplace is deteriorated. Therefore, when the steel sheet is heated by the electric resistance method, there should be no smoke.

After the heat-expanded band steel sheet is fixed to the CRT, it takes some time until the final assembly process, and the band steel sheet should be protected from corrosion in various surrounding environments.

In order to apply the resin solution on the steel sheet, the resin solution is put in a coater pan (5) and applied in the same manner as in FIG. First, the coating roll is a coater pan (5) for supplying a solution, a pick-up roll (1) for raising the solution from the coater pan, and a solution transferred from the pickup roll to the applicator roll. It consists of a Transfer Roll (2) and an Applicator Roll (3) to finally apply the solution transferred from the pickup roll. The silicone resin used for the production of the shrinkage band is deposited on various rolls as the working time elapses, so that the solution transferred later is not evenly transferred to the steel sheet. In other words, when the silicone resin deposited on the coating roll is crushed between the coating rolls in a smooth state and deposited on the applicator roll, the surface uniformity on the original rubber roll falls and the surface becomes uneven. This causes the solution transferred from the transfer roll to build up on an uneven surface and transfer the solution to the steel sheet. After the steel sheet transferred by the non-uniform coating roll is wet, the uniformity of the wet film of the steel sheet is dried and passed through the baking furnace, surface defects occur on the steel sheet, which affects the overall physical properties.

On the other hand, the prior art related to the present invention is Japanese Patent Application Laid-open No. Hei 12-15741. The prior art relates to a zinc-based galvanized steel sheet having excellent heat discoloration resistance, fume resistance upon heating, corrosion resistance and scratch resistance after heating, and a straight silicone resin film on the surface of the zinc-based galvanized steel sheet in terms of SiO _{2 in} terms of 0.1 to 3 It is characterized by forming in g / m ² . However, the prior art has a problem of environmental pollution because the silicone resin is a solvent type.

Accordingly, the present invention provides a resin solution for resin coated steel sheet that can significantly improve roll coating property and surface quality by mixing water-soluble silicone resin and silica in consideration of environmental friendliness, and adding nano silicate and silicon leveling agent. Using this, to provide a method for producing a resin coated steel sheet having excellent roll coating properties, the purpose is.

1 is a diagram showing the configuration of a coating roll for resin solution coating

* Description of the symbols for the main parts of the drawings *

1 .... Pick-up Roll

2 .... Transfer Roll

3 .... Applicator Roll

4 .... Back-up Roll

5 .... Coater Pan

The present invention for achieving the above object, the water-soluble silicone resin as the main resin, nano silicate: 2 to 10 parts by weight, silica: 100 to 140 parts by weight, silicon leveling agent: 0.3 ~ to 100 parts by weight of the main resin It is related with the resin solution for resin coated steel sheets which is excellent in roll coating property and surface quality containing 1.0 weight part.

Further, the resin solution is coated on a chromate-plated zinc-based alloy plated steel sheet and baked at a steel sheet temperature of 200 to 250 ° C. to provide a resin coated steel sheet having excellent roll coating property and surface quality. It relates to a manufacturing method of.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing a resin coated steel sheet using a resin solution and a resin solution excellent in roll coating properties and surface quality, and to examine the contents separately.

[Resin solution]

The resin solution is prepared by adding a silicate and a silicon leveling agent to a silica resin and then adding nano silicate to improve roll coating properties. do.

Silicone resin: 100 parts by weight of main resin

In the case of the silicone resin, since the resin molecule structure has a siloxane bond, it is composed of a compound that is stable at high temperature, and thus has excellent thermal decomposition ability. The silicone resin should contain at least one phenyl group and methyl group in the polymer resin, and the higher the phenyl group content, the better the flame resistance.

Nano silicate: 2 to 10 parts by weight based on 100 parts by weight of main resin

Nano silicate is added to the silicone resin. If the content of the nano silicate is less than 2 parts by weight, the nanosilicate content is too small in the resin layer, so that the corrosion resistance is less. If the content exceeds 10 parts by weight, the nanosilicate particles are present in the layered solution. Since the viscosity of the solution is too high to cause streaks and the like when coating the resin solution (coating), it is preferable to limit the content to 2 to 10 parts by weight relative to the resin content.

It is more preferable that the nano silicates use plate-shaped nanosilicates in order to have an excellent corrosion blocking effect. An example of a method of nanodispersing the silicates (dispersing in nanometers [nm]) is a silicate called Montmorillonite (M ^{n +} .yH ₂ O [Al _4x Mg _x ] (Si ₈ ) O ₂₀ (OH ₄ )). Swelling with pure water, an organic agent called alkylammonium which is hydrophobic, increases the spacing between layers, and breaks it into thin plates in an aqueous solution and disperses them in solution. The plate-shaped nanosilicate has a particle diameter in nanometer (nm) unit like silica, and the plate-shaped nano silicate is more effective in blocking external corrosion factors than spherical or acicular silica. In addition, in the case of silica, it is usually added to obtain a filling effect, but when the pH is not well matched in the solution, the corrosion blocking effect is inferior to that of the nano silicates because they aggregate together to form secondary particles.

Silica: 100 to 140 parts by weight based on 100 parts by weight of the main resin

In the present invention, when the nano silicate is present in the film layer by layer, the fine spaces between the layers are filled with silica to form a perfect and dense film structure. If the content of the silica is less than 100 parts by weight, the main resin content is increased and the flame resistance is insufficient. If the content of the silica is more than 140 parts by weight, the content of silica is too high in the resin film, so that the resin layer film is hardened and the resin adhesion is deteriorated. It is preferable to limit the content to 100 to 140 parts by weight relative to the resin content.

Silicone leveling agent: 0.3 to 1.0 part by weight based on 100 parts by weight of the main resin

The silicone leveling agent is usually used as a release material, the release material has a property to easily separate the molding at the interface between the molding and the mold. Examples of the silicone leveling agent include polysiloxane-based leveling agents, teflon-based leveling agents, silicone oils, and the like, and all can be used, but in order to obtain better flame resistance, polysiloxane-based leveling agents or silicone oils are more preferable.

The silicone leveling agent is added to improve the roll coating property, and is present between the silicone resin having a low softening point and the roll surface during roll coating, to prevent the silicone resin from sticking to the roll, and to inject the silicon leveling. The agent lowers the surface tension of the wet film and serves to improve the surface appearance of the dry film.

When the content of the silicone leveling agent is less than 0.3 parts by weight, the release performance with various rolls is not good during roll coating, and when the amount is more than 1.0 parts by weight, the effect of the silicon leveling agent is excessive and the amount of the silicone leveling agent is excessively added. In order to weaken the adhesive force of resin and a steel plate, it is preferable to limit the content to 0.3-1.0 weight part with respect to resin content.

[Method of manufacturing resin coated steel sheet]

The chromate treatment is performed on the zinc-based alloy plated steel sheet, and the resin solution prepared as described above is coated thereon by a roll coating method (FIG. 1). In Figure 1, the strip is a chromate-plated zinc-based alloy plated steel sheet. The steel sheet coated with the resin solution is baked at 200 to 250 ° C. At this time, when baking below 200 ° C., the coating becomes unstable, and when baking temperature exceeds 250 ° C., it is economically disadvantageous, so it is preferable to set baking temperature to 200 to 250 ° C.

If the resin coating film thickness of the resin coated steel sheet obtained by baking according to the present invention is less than 0.5 μm, it is difficult to secure corrosion resistance. If it exceeds 3.0 μm, the resin composition has a large amount of resin, which is not good for flame resistance. It is most preferable to adjust to 3.0 micrometers.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

After plating the zinc-nickel electroalloy plated steel sheet having a coating adhesion of 20 g / m 2, roll coating is performed while changing the type and content of each additive in the water-soluble silicone resin. The steel sheet is treated to have a baking temperature of 200 ° C., and then water cooled immediately to prepare a shrinkage band steel sheet having a dry thickness of 1.0 μm.

Flame resistance evaluation is to expand the band steel sheet to about 600 ℃ by using a resistance heating method by holding a metal grip on both sides of the 50x150mm band steel sheet. Table 1 shows the results of evaluating the presence or absence of smoke generated from the surface of the band steel sheet during the resistance heating and visual observation of the surface after heating.

Roll coating property is evaluated by time period that the silicone resin is pressed on the roll when the roll is idling in the roll coater equipment as shown in FIG. At this time, the circumferential speed ratio between the rolls was PUR (Pick-up Roll): TFR (Transfer Roll): APR (Applicator Roll) = 30-50 rpm: 30-50 rpm: 60-100 rpm, and the evaluation results are shown in Table 1.

The surface quality was evaluated by visually observing the stripe on the steel sheet after roll coating and baking the steel sheet temperature to 200 ℃. The results are shown in Table 1.

Corrosion resistance 8 hours after the salt spray test 16 hours after stopping the salt spray and left in the salt sprayer after 7 cycles of the test, the white rust and red blue (red rust) generated in the specimen of 50x150mm size rust) to evaluate the degree of occurrence, the results are shown in Table 1 below.

As shown in Table 1, when applied using the resin solution prepared according to the present invention (Inventive material A ~ L), when not manufactured according to the present invention (Comparative Materials 1, 2, 4, 6-7) Compared with flame resistance, surface quality, roll coating and corrosion resistance can be seen.

In the case of the comparative materials (3, 5) to which the leveling agent was added more than the limit of the present invention, the flame resistance, the surface quality, the roll coating property and the corrosion resistance were excellent, but the adhesion between the silicone resin and the steel sheet was poor.

Moreover, it turns out that flame resistance is more excellent compared with the case where a polysiloxane-leveling agent and silicone oil are used (inventive material A-H), and when using a teflon-type leveling agent (inventive material I-L).

Example 2

After plating the zinc-nickel electroalloy plated steel sheet having a coating weight of 20 g / m 2, the additive is added to the water-soluble silicone resin as shown in Table 2, followed by roll coating. The steel sheet was treated to a baking temperature of 200 ° C., and then immediately water cooled to change the dry thickness of the resin layer while evaluating flame resistance, surface quality, roll coating property, and corrosion resistance. 2 is shown.

As shown in Table 2, it can be seen that the resin M ~ O of the resin film thickness is 0.5 ~ 3.0㎛ excellent in flame resistance, surface quality, roll coating properties and corrosion resistance. However, in the case of the comparative materials 8 and 9 whose resin thickness is outside the limit of the present invention, it can be seen that the corrosion resistance and the flame resistance are inferior, respectively.

As described above, the present invention improves the flame resistance of the resin film by adding nano silicate and silica to the water-soluble silicone resin and by adding a silicone leveling agent to the shrinkage for TV or monitor, which has greatly improved roll coating property and surface quality. It provides a method for producing a resin coated steel sheet for the band.

Claims (6)

The roll coating property and surface which make a water-soluble silicone resin the main resin, and comprise nano silicate: 2-10 weight part, silica: 100-140 weight part, and a silicone leveling agent: 0.3-1.0 weight part with respect to 100 weight part of main resins Resin solution for resin coated steel sheet with excellent quality. The resin solution of claim 1, wherein the nanosilicate is plate-shaped. The resin solution for resin coated steel sheet having excellent roll coating property and surface quality according to claim 1, wherein a polysiloxane-based leveling agent or silicone oil is used as the silicon leveling agent. Chromating the resin solution which consists of water-soluble silicone resin as a main resin, and contains nanosilicate: 2-10 weight part, silica: 100-140 weight part, and a silicone leveling agent: 0.3-1.0 weight part with respect to 100 weight part of main resins A method for producing a resin coated steel sheet having excellent roll coating property and surface quality, which is applied to a treated zinc-based alloy plated steel sheet and then baked at a steel sheet temperature of 200 to 250 ° C., and has a resin coating film thickness of 0.5 to 3.0 μm. 5. The method of claim 4, wherein the nano silicate is plate-shaped. The method of manufacturing a resin coated steel sheet having excellent roll coating property and surface quality according to claim 4, wherein a polysiloxane-based leveling agent or silicone oil is used as the silicon leveling agent.