JP2000303143A - Resin coated galvanized steel sheet for heat shrink band - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a resin coated galvanized steel sheet for a heat shrink band holding strength equal to or above that of the conventional steel sheets, also maintaining sufficient magnetic shielding properties, small in color slippage, excellent in plating adhesion and moreover excellent in all of heating discoloring resistance, fuming properties at the time of heating, corrosion resistance after heating and flawing resistance. SOLUTION: On the surface of a galvanized steel sheet having >=24 kfg/mm2 yield stress, in which the product of magnetic permeability (μ) and sheet thickness in the magnetic field of 0.30 e is >=300, a straight silicone resin film of 0.1 to 3 g/m2 expressed in terms of SiO2 is formed to obtain a resin coated galvanized steel sheet for a heat shrink band. Moreover, if required, a chromate film of <=100 mg/m2 expressed in terms of metallic Cr is formed below the resin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated galvanized steel sheet applied to a heat shrink band for tightening around a panel portion of a color cathode ray tube such as a television.

[0002]

2. Description of the Related Art In a color cathode ray tube, the inside of the tube is 1.0 ×.
Since it is in a high vacuum state of 10 ^-7 Torr, from the viewpoint of preventing deformation of the panel surface and preventing internal explosion of the tube,
A heat shrink band made of a steel plate formed in a band shape is provided around the panel portion, and thereby tension is applied to correct the deformation of the panel surface.

Further, such a heat shrink band also has a function of shielding terrestrial magnetism as well as an internal magnetic shield, thereby preventing a displacement of an impact position of an electron beam on a fluorescent screen due to terrestrial magnetism. It has a function of preventing color shift from occurring.

Conventionally, a steel plate obtained by applying plating to a mild steel plate having a yield stress of about 24 kgf / mm ² has been used for this heat shrink band, but its geomagnetic shielding properties are insufficient, and the color is poor. The effect of preventing displacement is not sufficient.

Further, when exposed to a high-temperature environment such as a heat shrink band of a cathode ray tube of a television, an organic resin film is applied to the surface of the galvanized steel sheet. Odor and deterioration of corrosion resistance. Also,
When only chromate treatment is used without using an organic resin film,
Although there is no organic component, discoloration during heating is suppressed, but there is a problem that the film is extremely thin, so that the film is damaged during processing, the appearance is deteriorated, and the corrosion resistance of the damaged part is deteriorated.

[0006]

As described above, the conventional heat shrink band has insufficient magnetic shielding properties, cannot be said to have a sufficient color shift prevention performance, and has excellent color shift prevention performance. Galvanized steel sheets for heat shrink bands are desired. In addition, plated steel sheets are required to have essentially high plating adhesion. Further, it is required to be excellent in discoloration upon heating, corrosion resistance and scratch resistance.

The present invention has been made in view of the above circumstances, and maintains strength equal to or higher than that of a conventional steel sheet, maintains sufficient magnetic shielding properties, has little color shift, and has excellent plating adhesion. Another object of the present invention is to provide a resin-coated galvanized steel sheet for a heat shrink band, which is excellent in heat discoloration resistance, smoke generation during heating, corrosion resistance after heating, and scratch resistance.

[0008]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and have obtained the following findings. (1) Permeability μ and thickness t at 0.3 Oe (geomagnetic level) of the heat shrink band steel sheet after plating is applied
When the product μ × t is 300 or more, an improvement in geomagnetic drift can be seen. (2) In order to make the strength and the geomagnetic drift equal to or higher than those of conventional steel while maintaining the above magnetic permeability, Si must be contained
0.2% or more is required. (3) If the amount of Si in the steel exceeds 3% by weight, the plating adhesion decreases. (4) By treating the surface of galvanized steel sheet with a treatment liquid containing a specific straight silicone resin as a main component, it is possible to achieve resistance to discoloration upon heating, smoke generation during heating, corrosion resistance after heating and scratch resistance. The ability to obtain excellent resin-coated galvanized steel sheets.

The present invention has been completed based on such knowledge, and the first invention has a yield stress of 24 kgf.
/ Mm ² or more, the product of the magnetic permeability μ and the sheet thickness in a magnetic field of 0.3 Oe is 300 or more,
providing a heat shrink band for resin-coated galvanized steel sheet, characterized in that at iO ₂ terms by forming a straight silicone resin film of 0.1 to 3 g / m ^2.

In the second invention, the yield stress is 24 kgf / mm.
A product of the magnetic permeability μ and the plate thickness in a magnetic field of ² or more and 0.3 Oe and a thickness of 300 or more is formed on the surface of a galvanized steel sheet having a chromate film of 100 mg / m ² or less in terms of metal Cr as a first layer; to provide a resin-coated zinc-plated steel sheet for heat shrink band which is characterized by comprising forming a straight silicone resin film of 0.1 to 3 g / m ² in terms of SiO ₂ thereon as a second layer.

[0011] A third aspect of the present invention relates to a method of manufacturing a semiconductor device, wherein C: 0.005% by weight.
Hereinafter, N: 0.005% or less, P: 0.1% or less, S:
0.02% or less, Si: 0.2% or more and 3.0% or less, M
n: 1.0% or less, sol. Al: not more than 1.0%, and the surface of a steel sheet whose balance is substantially Fe is galvanized, and the yield stress is 24 kgf / mm ² or more, 0.3
The product of the permeability μ and the plate thickness in the Oe magnetic field is 0.1 to 0.1% in terms of SiO _{2 on} the surface of a galvanized steel sheet having a thickness of 300 or more.
A resin-coated galvanized steel sheet for a heat shrink band, wherein a straight silicone resin film of 3 g / m ² is formed.

[0012] The fourth invention is a method of the invention, wherein C: 0.005% by weight.
Hereinafter, N: 0.005% or less, P: 0.1% or less, S:
0.02% or less, Si: 0.2% or more and 3.0% or less, M
n: 1.0% or less, sol. Al: not more than 1.0%, and the surface of a steel sheet whose balance is substantially Fe is galvanized, and the yield stress is 24 kgf / mm ² or more, 0.3
Forming a chromate film of 100 mg / m ² or less as a first layer on the surface of a zinc-based plated steel sheet having a product of the magnetic permeability μ and the sheet thickness in an Oe magnetic field of 300 or more as a first layer;
On top of that, as a second layer, 0.1 to 3 g / m _{2 in} terms of SiO _2.
^2. A resin-coated zinc-based plated steel sheet for a heat shrink band, wherein the straight silicone resin film is formed.

According to a fifth aspect of the present invention, in the second or fourth aspect, the chromate film is formed of trivalent chromium ion /
Total chromium ions (trivalent chromium ions + hexavalent chromium ions) are in a ratio of 2/10 to 6/10 by weight, and phosphate ions / total chromium ions are 1.0 to 4 by weight. 2.0, and a treatment liquid containing in the range of 0.0
Provided is a resin-coated galvanized steel sheet for heat shrink bands, which is dried at a temperature of 200 to 200 ° C.

In a sixth aspect based on the second or fourth aspect, the chromate film is formed of trivalent chromium ions /
Total chromium ions (trivalent chromium ions + hexavalent chromium ions) are in a ratio of 2/10 to 6/10 by weight, and phosphate ions / total chromium ions are 1.0 to 4 by weight. 0.0 and the particle size is 5-20.
nm colloidal silica in a weight ratio of colloidal silica /
Provided is a resin-coated galvanized steel sheet for a heat shrink band, wherein a treatment liquid containing all chromium ions in a range of 2.0 to 6.0 is applied and dried at 60 to 200 ° C.

According to a seventh aspect of the present invention, there is provided the resin-coated zinc-based heat shrink band according to any one of the first to sixth aspects, wherein the organic group contained in the straight silicone resin film is a methyl group. Provide plated steel sheets.

An eighth invention is the heat shrink band according to any one of the first to seventh inventions, wherein the SiO ₂ component in the straight silicone resin film is 60% or more of the total film weight. To provide resin-coated galvanized steel sheet.

In a ninth aspect of the present invention, in any one of the first to eighth aspects, the straight silicone resin film contains 20 parts of an organic lubricant having a softening point of 70 ° C. or more per 100 parts by weight of the straight silicone resin. Provided is a resin-coated zinc-based plated steel sheet for a heat shrink band, characterized by containing not more than part by weight.

In a tenth aspect based on any of the first to eighth aspects, the straight silicone resin film contains a crystalline lubricant in an amount of 20 parts by weight or less based on 100 parts by weight of the straight silicone resin. The present invention provides a resin-coated galvanized steel sheet for a heat shrink band, characterized by the following.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. First, the relationship between color misregistration and magnetic permeability will be described. C: 0.003%, Si: 1.35%, Mn:
0.20%, P: 0.05%, S: 0.003%, so
l. A steel having a composition of Al: 0.20% and N: 0.002% is melted in a laboratory and then hot-rolled.
After cold rolling to 2 mmt, annealing at 500 ° C. to 800 ° C. for 90 seconds, zinc was applied to both surfaces of the alloy plate by electroplating at 19 g / m ² , and processed into a band of a predetermined shape. After heating the band to 500 ° C, 29 inch TV
It was fitted into a cathode ray tube panel, and the geomagnetic drift property was evaluated. The result is shown in FIG.

The abscissa in the figure represents an external magnetic field equivalent to terrestrial magnetism of 0.3 O, which was measured after heat treatment equivalent to shrink fitting was performed on a ring test piece taken from a plated alloy plate before shrink fitting.
This is the value of the product μ × t of the magnetic permeability μ and the plate thickness t at e.

The magnetic drift property was evaluated based on the drift amount of the landing point of the electron beam due to terrestrial magnetism. The vertical axis in FIG. 1 indicates such a magnetic drift amount Bh,
Bv. Specifically, 0.35 Oe for CRT
With a vertical magnetic field of 0.3 Oe and a horizontal magnetic field of 0.3 Oe added,
The CRT was rotated by 360 °, the positional deviation (landing error) of the landing point of the electron beam with respect to the reference point was measured, and the value of the peak-to-peak was taken as the horizontal drift amount Bh. Further, the landing error when the horizontal magnetic field was set to 0 Oe and the vertical magnetic field was changed from 0 Oe to 0.35 Oe was measured as the vertical drift amount Bv.
In addition, the drift amount of the landing error on the vertical axis is shown as a relative value when the value of mild steel is 1.

As is clear from FIG. 1, when μ × t increases, both Bh and Bv tend to decrease, and the color shift due to terrestrial magnetism is improved by increasing μ × t.
It can be seen that when the value is 300 or more, the value is superior to that of the conventional steel.

Next, the relationship between the amount of Si and the amount and intensity of geomagnetic drift will be described. FIG. 2 shows C: 0.002.
%, Mn: 0.24%, P: 0.02%, S: 0.00
3%, sol. Al: 0.22%, N: 0.0028%
After cold rolling to 1.0 mmt, annealed at 700 ° C., then electroplated zinc on both sides of the steel sheet with an adhesion amount of 22 g / m ² , and worked into a band having a predetermined shape. To a 29-inch TV CRT panel at 600 ° C.
The results of inset after heating and evaluation of geomagnetic drift properties are shown.

When the amount of Si increases up to 2%, as the amount of Si increases, the magnetic permeability of the material increases, and as a result, the amount of geomagnetic drift decreases. In particular, when the Si content is 0.2% or more, a superior geomagnetic drift amount is obtained as compared with conventional steel. If it exceeds 2%, the magnetic permeability increases, but the effect of improving the geomagnetic drift amount is small. Although the cause is not clear, the high-temperature strength of the band steel material increases with the increase in the amount of Si in the steel,
It is considered that the adhesion between the band and the panel surface changed.

That is, when the amount of Si in steel increases, S
The solid-solution strengthening of i increases the high-temperature strength and the band tension at high temperatures. If the band shrinks during shrink fit and the strength is high when the panel starts to be tightened, the shape of the band deformed due to processing accuracy, uneven heating temperature, etc. is easily frozen, and the panel is cooled even to room temperature. The band does not adhere to the entire surface. As a result, the magnetic shield cannot be sufficiently performed, and the magnetic drift amount is not improved as much as the magnetic permeability is increased.

Next, the relationship between the amount of Si and the yield strength after plating will be described. FIG. 3 shows C: 0.002%, M
n: 0.24%, P: 0.02%, S: 0.003%,
sol. After hot-rolling steel after dissolving in a laboratory, the steel in which the amount of Si was changed with Al: 0.22% and N: 0.0028%,
Then, cold rolling is performed to 1.0 mmt,
After annealing at 0 ° C for 90 seconds, 19 g of zinc was electroplated.
/ M ² are the results of investigation of the yield strength by adhering to both surfaces. As shown in FIG. 3, the strength after plating is greater than that of conventional steel when the amount of Si in the steel is 0.2% or more.

Next, the results of an examination of the amount of Si in the steel and the adhesion between the steel and the plated material will be described. C: 0.003%, M
n: 0.25%, P: 0.05%, S: 0.003%,
sol. Al: 0.25% as a base composition, steel in which Si is changed from 0.1% to 3.5% is subjected to hot rolling after melting in a laboratory and then cold rolling to 1.2 mmt, respectively. After annealing at 700 ° C. for 90 seconds, zinc was adhered to both surfaces by electroplating at 20 g / m ^2. This steel sheet was subjected to a heat treatment equivalent to a shrink-fit of 600 ° C. for 5 seconds, and then subjected to close-contact bending, followed by a tape test. Table 1 shows the results of the evaluation of the peelability.

[0028]

[Table 1]

From this table, it can be seen that when Si exceeds 3%, the adhesion of the plating decreases, and peeling of the plating occurs at the time of close bending. On the other hand, when the amount of Si in the steel was less than 3%, no peeling of the plating was observed even in close contact bending. It is considered that when the amount of Si in the steel increases, an oxide film is formed on the surface of the steel sheet, and an unplated layer is easily formed. Therefore, the amount of Si in steel is desirably 3% or less.

Next, the base plated steel sheet will be described. The present invention has a yield stress of 24 kgf / mm ² or more,
The product of the magnetic permeability μ and the plate thickness in a magnetic field of 0.3 Oe is 30
By using a plated steel sheet of 0 or more, it is possible to effectively prevent color misregistration while maintaining the same strength as before,
As a preferable composition range of the base steel sheet, C:
0.005% or less, N: 0.005% or less, P: 0.1
%, S: 0.02% or less, Si: 0.2% or more
0% or less, Mn: 1.0% or less, sol. Al: 1.0
% Or less.

Hereinafter, the individual components will be described. (1) Si: 0.2% or more and 3.0% or less Si is the most important component in the present invention. By adding Si, it is possible to increase the magnetic permeability while increasing the strength by solid solution strengthening. As shown in FIGS. 2 and 3 described above, such a strength-permeability balance is excellent when Si is contained at 0.2% or more, and the strength-permeability is higher than that of conventional steel. But Si is 3%
If the content exceeds the range, workability will be significantly reduced. Therefore, the amount of Si is preferably in the range of 0.2% or more and 3% or less.
From the viewpoint of color misregistration, the Si amount at which the drift amount is significantly improved is more preferably 1% or more and 2% or less.

(2) C: 0.005% or less C is an element contributing to the strengthening of the steel sheet, but is not more preferable for the magnetic permeability. To prevent the adverse effect on the magnetic permeability, C is 0.005% or less. It is preferable that

(3) Mn: 1.0% or less Mn is preferably added in an amount of 0.1% or more to improve hot ductility. However, if added in excess of 1.0%, the magnetic permeability will be degraded, so it is preferable to limit the content to 1.0% or less.

(4) P: 0.1% or less P is an element contributing to the strengthening of the steel sheet, and may be added as necessary. However, if the content exceeds 0.1%, the steel sheet is embrittled, causing problems such as coil breakage during cold rolling. Therefore, the P content is preferably 0.1% or less.

(5) S: 0.02% or less S is not preferable for both hot ductility and magnetic permeability, and is preferably 0.02% or less from the viewpoint of not adversely affecting these.

(6) sol. Al: 1.0% or less sol. Al deteriorates workability. In order to prevent this effect, the content is preferably set to 1.0% or less.

(7) N: 0.005% or less Like C, N is an element that is not preferable for magnetic permeability because it contributes to strengthening of a steel sheet. To prevent this adverse effect, its content is made 0.005%. It is preferable that

The galvanized steel sheet as the base of the present invention is a galvanized steel sheet produced by electroplating, hot-dip galvanization, or vapor deposition plating, and at least one of nickel, iron, aluminum, cobalt, molybdenum, magnesium and the like in addition to zinc. Zinc alloy-plated steel sheet containing one component, and dispersion-plated steel sheet containing silica, alumina, etc. in a plating film. More preferably, from the viewpoint of heat resistance, a zinc-nickel alloy-plated steel sheet and a zinc-55% aluminum alloy-plated steel sheet having a high melting point of the plated metal. The base steel sheet serving as the base of the galvanized steel sheet is not particularly limited, and various compositions, surface roughness, and rolling methods can be used. Although the present invention is directed to zinc-based plating, a hot-rolled steel sheet, a hot-rolled steel sheet having no plating film, a hot-rolled steel sheet having no plating film, a hot-rolled steel sheet having no plating film, and the like can also be applied.

Next, a film formed on the surface of the plating film will be described. The plated steel sheet of the present invention has a coating mainly composed of a specific straight silicone resin on the surface of a zinc-based plated steel sheet. This film is formed by applying and baking a treatment liquid containing a specific straight silicone resin as a main component. Silicone is a general term for a material having a siloxane (-Si-O-Si-) portion, and is used for resins, oils, rubbers, and the like.

The straight silicone resin used in the present invention has a siloxane (—Si—O—Si—) skeleton, and a hydroxyl group (—OH) and an alkoxyl group (—OR:
R is an organic group) or a material having an organic group bonded thereto and having both organic and inorganic properties, and is characterized by being not modified with other organic resins. Further, the film is flexible because it does not have a crosslinked structure, and is characterized by having excellent scratch resistance. As an organic group bonded to a silicon atom,
_(-CH 3), an ethyl group _{(-C 2 H} 5), phenyl group _{(-C 6 H} 5), a vinyl group (-CH = _CH 2), a butyl group _(-C 3 _{H 7)} can be mentioned. In addition, the straight silicone resin used may contain these organic groups alone, or may contain two or more different organic groups. It is not preferable to use a modified silicone resin other than a straight silicone resin because the modified organic resin component thermally decomposes when heated, causing discoloration and smoking. Further, among the organic groups, a methyl group having a small number of carbon atoms is more preferable from the viewpoint of preventing generation of smoke due to decomposition of the organic component due to heating.

The adhesion amount of the straight silicone resin is Si
O ₂ conversion preferably set to 0.1 to 3 g / ^{m 2} at. An amount of less than 0.1 g / m ² is not preferable because it has poor scratch resistance during roll forming and press molding, and an amount exceeding 3 g / m ² is inferior in smoke emission during heating and adhesion during bending.

S contained in straight silicone resin
Preferably, the iO ₂ component accounts for at least 60% of the total coating weight. This is SiO _{2 in} straight silicone resin
This is because the components other than the components are hydroxyl groups or organic groups, and when the number of organic groups increases, the smoke-generating properties deteriorate.

The silicone resin film has a softening point of 7
It is preferable to add an organic lubricant at 0 ° C. or higher. The reason for adding the organic lubricant is that the organic lubricant has an effect of more effectively preventing scratches and galling on the resin film and the plating surface caused by roll forming, press molding and the like. The softening point was set to 70 ° C. or higher because
If the temperature is lower than 70 ° C., the organic components are easily decomposed and the smoke emission is inferior. Examples of the organic lubricant having a softening point of 70 ° C. or higher include microsterin wax (softening point of 70 to 90 ° C.) and polyethylene (softening point of 90 to 140 ° C.).
° C), polypropylene (softening point 140-170 ° C), 4
And ethylene fluoride (softening point: 320 ° C.). The above-mentioned lubricants may be added alone, or two or more different lubricants may be used in combination. The acid value of microstalin wax, polyethylene, or polypropylene may be 0 or more than 0, or a combination thereof. Since the silicone resin is of a solvent type, it is preferably added in a powder or in a state of being dispersed in a solvent in advance, and the particle size is preferably 20 μm or less from the viewpoint of scratch resistance.

In addition to the above-mentioned organic lubricants, inorganic crystalline lubricants can be used as the above-mentioned lubricant. Examples of such a crystalline lubricant include graphite, boron nitride, molybdenum disulfide, and the like. Such a lubricant can be preferably used when fuming properties are important, but it may be slightly inferior in scratch resistance compared to organic ones, and is appropriately selected and used depending on the purpose of use. Is preferred.

The amount of the lubricant added is preferably not more than 20 parts by weight based on 100 parts by weight of the straight silicone resin, both of the organic lubricant and the crystalline lubricant. In the case of an organic lubricant, if the addition amount is more than 20 parts by weight, the organic component increases, so that the smoke generating property at the time of heating is inferior. A more preferable addition amount is 10 parts by weight or less from the viewpoint of fuming properties. In addition, in the case of an inorganic crystalline lubricant, if the addition amount exceeds 20 parts by weight, the scratch resistance is deteriorated, which is not preferable.

A coating mainly composed of a straight silicone resin as described above is applied to the surface of a galvanized steel sheet, heated and dried to form a film. Specifically, a roll coater,
A predetermined amount of a coating film is formed by applying the above-described paint mainly composed of the straight silicone resin by a known method such as a curtain flow coater or spray coating. Next, the zinc-coated steel sheet coated with the coating material is preferably heated to 80 to 30 by a hot blast stove or an induction heating device.
By heating to a temperature of 0 ° C. and baking, the solvent in the paint is volatilized to form a resin film. When a chromate film is formed on a plated steel sheet as described later, the above-mentioned resin film may be similarly formed on the chromate film surface.

The reason why the baking temperature of the resin film is preferably in the range of 80 to 300 ° C. is that if the baking temperature is lower than 80 ° C., the resin film is insufficiently hardened, resulting in poor scratch resistance during processing. If the temperature exceeds 300 ° C., the curing of the resin film proceeds too much, and the organic groups in the straight silicone resin are decomposed and volatilized, resulting in poor scratch resistance.

In forming the above resin film,
For the purpose of improving corrosion resistance, it is effective to form a chromate film as a first layer on a zinc-based plating layer of a zinc-based plated steel sheet, and to form the above-mentioned resin film as a second layer thereon. The method for forming the chromate film may be performed by any known means such as coating treatment, electrolytic treatment, and reaction treatment.

The amount of the chromate film adhered is preferably 100 mg / m ² or less per one surface of the steel sheet in terms of metallic Cr. If the amount of the chromate film adhered is more than 100 mg / m ² , the effect of improving the corrosion resistance after heating corresponding to the amount of the chromate film not only cannot be obtained, but also the cohesive failure of the chromate film itself occurs during the processing, and the adhesiveness cannot be obtained. Therefore, it is not preferable. The chromate film is necessary to improve the corrosion resistance before heating.

The treatment liquid for forming the chromate film is a trivalent chromium ion / total chromium ion (trivalent chromium ion + hexavalent chromium ion) weight ratio of 2/10 to 6/1.
It is preferable that phosphate ion / total chromium ion be contained in a weight ratio of 1.0 to 4.0. Further, it is preferable that colloidal silica having a particle diameter of 5 to 20 nm is contained in a weight ratio of colloidal silica / total chromium ions in a range of 2.0 to 6.0.
When any of these is not satisfied, any of the discoloration after heating and the corrosion resistance before heating may be reduced.

That is, when the ratio of trivalent chromium ion / total chromium ion in the chromate treatment liquid is less than 2/10, the yellowish tint increases and the discoloration after heating becomes undesirably large.
If it is more than 0, the stability of the processing solution is inferior, so that it is not preferable. Further, phosphate ions are effective in reducing the yellow tint of the chromate film, and thus can very effectively suppress discoloration after heating. If the phosphate ion is less than 1.0, the effect of suppressing discoloration after heating is not sufficient, and if it is 4.0 or more, the stability of the treatment liquid is poor, which is not preferable. Further, the corrosion resistance before heating can be improved by adding colloidal silica. However, if the amount of colloidal silica added is less than 2.0, the effect of improving the corrosion resistance is not sufficient, and 6.0 is not sufficient.
If it exceeds, not only the effect of improving the corrosion resistance is saturated, but also the stability of the treatment liquid is inferior. The preferable range of the particle size of the colloidal silica is 5 to 20 nm. If the particle size is less than 5 nm, the effect of improving corrosion resistance is not only economically unsatisfactory but is not preferable. It is not preferable because it is insufficient.

[0052]

EXAMPLE After melting the test steels shown in Table 2, they were reheated to 1200 ° C., and the sheet thickness was 820 ° C. and the winding temperature was 680 ° C.
It was hot rolled to 2 mm. The obtained hot-rolled sheet is pickled and cold-rolled to a sheet thickness of 0.8 to 1.2 mm.
Annealing was performed for 0 second, and zinc plating of the following (1) to (6) was applied to both surfaces of the steel sheet. After both sides of this zinc-coated steel sheet are alkali-degreased, a coating mainly composed of a straight silicone resin is applied to the plating surface by a roll coating method (adhesion amount is adjusted by a wet application amount), and then this is heated by an induction heating furnace. Baking was performed in the range of the maximum attained plate temperature of 60 to 320 ° C to prepare a test material. Fig. 4 shows the structure of this test material.
(A) of FIG. In addition, some test materials were subjected to a coating type chromate treatment of 30% in terms of metal Cr before forming the resin film.
１５０150 mg / m ^{2 was} formed. The structure of this test material is shown in FIG.

(1) Electrogalvanized steel sheet (plating adhesion 2
0 g / m²(2) Zinc / nickel alloy plated steel sheet (coating weight 2
0 g / m²(3) Hot-dip galvanized steel sheet (coating weight 90g /
m²(4) Alloyed hot-dip galvanized steel sheet (coating weight: 45 g)
/ M²(5) Hot-dip zinc-5% aluminum alloy coated steel sheet
90g / m ²(6) Hot-dip zinc-55% aluminum alloy plated steel sheet
(Plating adhesion amount 70g / m²)

[0054]

[Table 2]

Tables 3 to 7 show the types of plating, resin films and chromate films used for each test material. The symbols in the “plating” columns in these tables are as follows. UZ: Electro-galvanized steel sheet EZN: Zinc-nickel alloy-coated steel sheet GI: Hot-dip galvanized steel sheet GA: Alloyed hot-dip galvanized steel sheet GF: Hot-dip zinc-5% aluminum alloy-coated steel sheet GL: Hot-dip zinc-55% aluminum alloy-coated steel sheet

[0056]

[Table 3]

[0057]

[Table 4]

[0058]

[Table 5]

[0059]

[Table 6]

[0060]

[Table 7]

The test materials prepared in the above manner were evaluated for geomagnetic drift, yield stress, DC magnetic properties, heat discoloration, smoke generation, corrosion resistance after heating, scratch resistance, and bending adhesion.

These performance evaluations were performed as follows. (1) Geomagnetic Driftability It was processed into a band of a predetermined shape, fitted to a 29-inch TV cathode ray tube panel after heating at 600 ° C., and the geomagnetic drift property was evaluated.

(2) Yield stress A 700 ° C. annealed plate was subjected to heat shrink at 600 ° C.
After heating for 5 seconds and air cooling to room temperature, the yield stress was measured.

(3) DC magnetic characteristics A 700 ° C. annealed plate was heat-shrinked at 600 ° C.
After heating for 5 seconds and air cooling to room temperature, the magnetic permeability at 0.3 Oe and the coercive force when excited to 0.5 T were evaluated.

(4) Heat-Resistant Discoloration After each test material reached a plate temperature of 600 ° C., it was heat-treated for 1 hour, and the discoloration of the surface of the test material was visually determined. The evaluation criteria are as follows. ◎: No change ○: Discolored to light gray △: Discolored to blue ×: Discolored to brown

(5) Smoke-producing property The smoke-producing state of each test material before the reaching plate temperature reached 600 ° C. was visually judged. The evaluation criteria are as follows. ◎: No fumes ○: Smoke is slightly observed △: Smoke is clearly observed ×: Smoke is remarkably generated

(6) Corrosion resistance after heating After the test material reached a plate temperature of 600 ° C., a plurality of 70 mm × 150 mm test pieces were cut out from the heat-treated for 1 hour, and these test pieces were specified in JISZ2371. The salt spray test was performed, and the area of red rust occurrence after 500 hours was visually determined. The evaluation criteria are as follows. ◎: No red rust generation ○: Red rust generation area 5% or less △: Red rust generation area 5% or more 30% or less ×: Red rust generation area 30% or more

(7) Scratch resistance A tester shown in a schematic front view in FIG. 5 was used. As shown in FIG. 5, the tester includes a female die 1 having a flat surface fixed to one side 2a of a box-shaped frame 2, and a substantially horizontal ridge of a predetermined height facing the female die 1. A male die 4 having a male die 3 and the other side 2b of the frame 2 for supporting the male die 4 and moving the male die 4 horizontally toward the female die 1
And a hydraulic cylinder 5 fixed to the hydraulic cylinder. The male die 4 is fixed to a rod 5 a of a hydraulic cylinder 5 via a load cell 6. In addition, the width | variety of the protrusion 3 of the male die 4 is 10 mm, and the length of the front-end | tip is 1 mm.

The test material is inserted vertically into the gap between the female die 1 and the male die 4 and the hydraulic cylinder 5 is operated to
50 kgf of test material 7 by female die 1 and male die 4
(500 kgf / cm ² ). Next, the test material 7 was pulled upward at a speed of 500 mm / min, as indicated by an arrow, and damage to the coating and plating of the portion slid at that time was visually evaluated. The evaluation criteria are as follows. ◎: No damage ○: Slight damage to the coating, but no plating damage △: Damage to the coating, small plating damage ×: Damage to the coating, large plating damage

(2) Bending adhesion The test material was subjected to 0T adhesion bending, a cellophane tape was stuck to the bent portion, rubbed well and adhered sufficiently, and then peeled off, and the degree of the peeled plating and film was visually evaluated. did. The evaluation criteria are as follows. ◎: No peeling ○: Slight peeling △: Partial peeling ×: Almost peeling

Tables 8 and 9 show the evaluation results. As shown in these tables, the yield stress YS ≧ 24 kg
It was confirmed that the examples of the present invention satisfying f / mm ² and μ × t ≧ 300 also have good plating adhesion. On the other hand, in the comparative example which does not satisfy any of the yield stress YS ≧ 24 kgf / mm ² and μ × t ≧ 300, any of the strength, the magnetic permeability, and the adhesion are out of appropriate values, and the It was confirmed that the heat shrink band did not have sufficient properties. Also, as is clear from Tables 8 and 9, the zinc-coated steel sheet on which the coating according to the present invention was formed was:
All were confirmed to be excellent in heat discoloration resistance, smoke generation, corrosion resistance after heating, scratch resistance and bending adhesion. On the other hand, it was confirmed that the comparative example was inferior in any of the heat discoloration resistance, the smoke emission property, the corrosion resistance after heating, the scratch resistance, and the bending adhesion.

[0072]

[Table 8]

[0073]

[Table 9]

[0074]

As described above, according to the present invention,
By applying a specific resin film to a galvanized steel sheet that satisfies YS ≧ 24 kgf / mm ² and μ × t ≧ 300, it has excellent color misregistration properties, excellent thermal discoloration, smoke generation, and corrosion resistance after heating. The present invention provides a resin-coated galvanized steel sheet which has excellent properties such as scratches and adhesion of a coating film and a plating surface when processed as a heat shrink band.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a plating and a geomagnetic drift after a film is formed.

FIG. 2 is a diagram showing the relationship between the Si amount of a steel sheet and Bh and Bv.

FIG. 3 is a view showing YS between the amount of Si of a steel sheet and the state after plating + film formation.

FIG. 4 is a schematic view showing a film structure of the present invention.

FIG. 5 is a schematic front view showing a flaw resistance tester used for evaluation of flaw resistance in Examples.

[Explanation of symbols]

 1, 4; bead 2; frame 3; ridge 5; hydraulic cylinder 6; load cell 7;

Continued on front page (72) Inventor Takahiro Kubota 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masaru Sagiyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Stock In-company (72) Inventor Nobuo Yamagami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Hiroaki Kato 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Teruo Takeuchi 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Chopachi Sato 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation F Term (reference) 4F100 AA04A AA20B AA22C AA36A AB02A AB04A AB10A AB11A AB14A AB18D AB31A AK52B BA03 BA04 BA07 BA10A BA10B CA19B EH41B EH71D EJ68A EJ69C GB48 JA04B JA11B JBA JA02A10A BB10 CA19 CA20 CA23 CA41 DA02 DA11 DA15 DA16 EB08 5C032 AA02 CC03 CD01

Claims (10)

[Claims] (1) a yield stress of 24 kgf / mm ² or more;
The product of the magnetic permeability μ and the plate thickness in a magnetic field of 0.3 Oe is 30
The surface of 0 or more galvanized steel sheet, a resin-coated zinc-plated steel sheet for heat shrink band which is characterized by comprising forming a straight silicone resin film of 0.1 to 3 g / m ² in terms of SiO _2. 2. A yield stress of 24 kgf / mm ² or more,
The product of the magnetic permeability μ and the plate thickness in a magnetic field of 0.3 Oe is 30
On a surface of a zinc-plated steel sheet of 0 or more, a chromate film of 100 mg / m ² or less in terms of metal Cr is formed as a first layer, and 0.1 to 3 in terms of SiO ₂ as a second layer.
A resin-coated galvanized steel sheet for a heat shrink band, wherein a g / m ² straight silicone resin film is formed. C .: 0.005% or less, N:
0.005% or less, P: 0.1% or less, S: 0.02%
Hereinafter, Si: 0.2% or more and 3.0% or less, Mn: 1.0 or less
% Or less, sol. Al: 1.0% or less, the balance being substantially Fe, the surface of a steel sheet is zinc-plated, the yield stress is 24 kgf / mm ² or more, and the magnetic permeability μ and the sheet thickness in a magnetic field of 0.3 Oe are obtained. Characterized in that a straight silicone resin coating of 0.1 to 3 g / m ^{2 in} terms of SiO ₂ is formed on the surface of a zinc-based plated steel sheet having a product of 300 or more. steel sheet. 4. C .: 0.005% or less, N:
0.005% or less, P: 0.1% or less, S: 0.02%
Hereinafter, Si: 0.2% or more and 3.0% or less, Mn: 1.0 or less
% Or less, sol. Al: 1.0% or less, the balance being substantially Fe, the surface of a steel sheet is zinc-plated, the yield stress is 24 kgf / mm ² or more, and the magnetic permeability μ and the sheet thickness in a magnetic field of 0.3 Oe are obtained. On the surface of a galvanized steel sheet having a product of 300 or more, as a first layer, 100 m in terms of metal Cr.
g / m ² or less, and a second
Heat shrink band for resin-coated galvanized steel sheet characterized by comprising forming a straight silicone resin film of 0.1 to 3 g / m ² in terms of SiO ₂ as a layer. 5. The chromate film according to claim 1, wherein trivalent chromium ion / total chromium ion (trivalent chromium ion + hexavalent chromium ion) is in a ratio of 2/10 to 6/10 by weight, and further, phosphate ion is added in weight. A treatment solution containing phosphate ion / total chromium ion in a ratio of 1.0 to 4.0 in a ratio is applied,
3. Drying at 0-200 [deg.] C.
Or a resin-coated zinc-coated steel sheet for a heat shrink band according to claim 4. 6. The chromate film has a trivalent chromium ion / total chromium ion (trivalent chromium ion + hexavalent chromium ion) ratio of 2/10 to 6/10 by weight, and further contains phosphate ion in weight. The ratio contains phosphate ion / total chromium ion in a range of 1.0 to 4.0 and a particle size of 5 to 2
3. A treatment liquid containing a colloidal silica of 0 nm in a weight ratio of colloidal silica / total chromium ions in the range of 2.0 to 6.0 is applied and dried at 60 to 200 [deg.] C. The resin-coated galvanized steel sheet for a heat shrink band according to claim 4. 7. The resin-coated zinc-based plating for a heat shrink band according to claim 1, wherein an organic group contained in the straight silicone resin film is a methyl group. steel sheet. 8. The resin for a heat shrink band according to claim 1, wherein the SiO ₂ component in the straight silicone resin film accounts for 60% or more of the total film weight. Coated galvanized steel sheet. 9. The straight silicone resin film,
The heat shrink band according to any one of claims 1 to 8, wherein an organic lubricant having a softening point of 70 ° C or higher is contained in an amount of 20 parts by weight or less based on 100 parts by weight of the straight silicone resin. Resin-coated zinc-based coated steel sheet. 10. The straight silicone resin film according to claim 1, wherein the straight silicone resin contains 20 parts by weight or less of a crystalline lubricant based on 100 parts by weight of the straight silicone resin. 4. A resin-coated zinc-coated steel sheet for a heat shrink band according to item 1.