JP2003127272A - Insect-proof coated steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insect-proof coated steel plate which can exhibit sure insect-proof effects while controlling the use of an insecticide to reduce costs. SOLUTION: A colored coating film layer 3 is formed on the surface of a base material steel plate 1. A top layer 4 which is made as thin as possible in comparison with the layer 3 is formed on the surface of the layer 3. The top layer 4 is formed by applying a top coating obtained by incorporating an appropriate amount of the insecticide containing a dibasic acid saturated dialkyl ester and a synthetic pyrethroide compound into a colored coating of a similar color to that of the layer 3 of a clear coating on the layer 3. Preferably, the thickness of the dry coating film of the top layer 4 is made as thin as 2-20 μm to reduce the amount of the expensive insecticide, so that the production costs of the insect-proof coated steel plate can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated steel sheet having an insect repellent function, and more particularly to a coated steel sheet having a coating layer containing an insect repellent so as to exhibit the insect repellent function.

[0002]

2. Description of the Related Art It is known to add an insect repellent to a fiber product such as a fiber lump, a woven fabric or a rug to impart an insect repellent function. There, a thermoplastic resin in a molten state is kneaded with an insect repellent and then made into fibers to obtain secondary products such as fiber lumps, woven fabrics and rugs. It has been attempted to apply a technique of this kind to a coated steel sheet to impart a pest repellent function to kitchen utensils made of the coated steel sheet, such as kitchen cabinets and rice stockers. There, an insect repellent is added to the coating layer on the surface of the steel sheet so that the duration of the medicinal effect can be maintained. Specifically, after mixing the powdered insect repellent in the coating liquid and dispersing,
The paint is applied to the surface of the base steel sheet, baked and dried to form a coating layer.

[0003]

In the coated steel sheet formed as described above, only the insect repellent distributed near the surface of the coating layer exerts its medicinal effect. However, when the powdered insect repellent is mixed and dispersed in the coating liquid, the insect repellent disperses toward the lower layer in the coating liquid. Therefore, in order to exert a reliable insect pest repellent effect, it is necessary to mix a certain amount of the insect repellent in the paint, knowing that the insect repellent is dispersed and settled in the coating layer other than the surface. However, in that case, the amount of the insect repellent dispersed and settled in the coating layer other than the surface becomes overwhelmingly larger than the amount of the insect repellent distributed near the surface of the coating layer. As described above, the conventional coated steel sheet having the insect repellent function has many insect repellents which hardly disperse in the coating layer other than the surface and show almost no medicinal effect. ,
The cost of manufacturing painted steel sheets with insect repellent was high. It is easy to add a large amount of insect repellent to the paint to enhance the drug effect, but if the amount of the insect repellent exceeds a certain value, the coating becomes difficult. By the way, the insect repellent costs 100,000 yen per kg.

In addition, there are manufacturing problems. The coated steel sheet is
While continuously feeding the base steel sheet at a constant speed, surface treatment, coating, and then drying, etc. are performed.However, in the drying process, baking and drying are performed at a high temperature because it is necessary to synchronize with the feed rate of the base steel sheet. The drying time is shortened. Therefore, in the drying step, the insect repellent contained in the coating film layer is thermally decomposed by receiving the heat of drying, and the physical properties are changed to lose the medicinal effect. If the coating temperature is reduced by lowering the drying temperature and further slowing down the feed rate of the base steel sheet, the deterioration of the insect repellent can be eliminated, but the production rate of coated steel sheet is reduced by the lower feed rate of the base steel sheet. Sex is significantly impaired.

An object of the present invention is to provide a coated steel sheet having a insect repellent function at a low cost, since it can exert a positive insect repellent effect while using a smaller amount of insect repellent.
An object of the present invention is to eliminate the need for reducing the feed rate of the base steel sheet, to eliminate the thermal decomposition and alteration of the insect repellent in the drying step, and thus to efficiently produce a coated steel sheet having an insect repellent function. Is to improve the productivity of the steel sheet.

[0006]

As shown in FIG. 1, the insect-repellent coated steel sheet of the present invention has a colored coating layer 3 formed on the surface of a base steel sheet 1 and a top layer formed on the surface of the colored coating layer 3. 4 is formed by coating. The top layer 4 contains an insect repellent against 100 parts by weight of a paint having a color similar to or similar to that of the colored coating layer 3.
The top coating material obtained by blending 0.1 to 4.0 parts by weight is applied to the surface of the colored coating film layer 3 to be formed. The dry film thickness of the colored coating layer 3 is 7 to 40 μm, and the dry film thickness of the top layer 4 is 2 to 2
Each is set to 0 μm.

The insect repellent compounded in the top layer 4 is composed of a compound consisting of dibasic acid saturated dialkyl ester and a synthetic pyrethroid compound. The dry film thickness of the top layer 4 is desired to be 5 to 12 μm.

[0008]

According to the present invention, the colored coating film layer 3 is formed on the surface of the base material steel plate 1, and the thin top layer 4 containing the insect repellent is laminated on the surface of the colored coating film layer 3 for insect repellent coating. Since a steel sheet is formed, the amount of insect repellent used when the medicinal effect is the same can be significantly reduced as compared with a conventional insect repellent coated steel sheet in which an insect repellent is blended in a coating layer that is thicker than the top layer 4. Therefore, the cost required for manufacturing the insect-repellent coated steel sheet can be reduced by that amount, and the cost can be reduced. The top layer 4 is formed to be thinner than the colored coating layer 3 by applying a paint having a color similar to or similar to that of the colored coating layer 3, so that the design effect of the colored coating layer 3 can be exerted as it is, and the conventional coated steel sheet. It is possible to obtain a coated steel sheet that can exhibit the same appearance as the above, and that also has a pest repellent action.

The top layer 4 is formed by the top coating obtained by blending the insect repellent in an amount of 0.1 to 4.0 parts by weight when the amount of the repellent is less than 0.1 part by weight. This is because it becomes difficult for the effect to be exhibited. On the other hand, if the content of the insect repellent exceeds 4.0 parts by weight, the gloss of the top layer 4 after baking and drying becomes dull, and it becomes difficult to form a coating film having a smooth and uniform thickness. . As the amount of the insect repellent compounded increases, it also means that the production cost of the insect-repellent coated steel sheet is kept high. The dry film thickness of the colored coating film layer 3 is set to 7 to 40 μm. The reason is that when the dry film thickness of the colored coating film layer 3 is less than 7 μm, the color hiding property of the colored coating film layer 3 is lost and the primer layer 2 is See through. On the other hand, if the dry film thickness of the colored coating layer 3 exceeds 40 μm, it becomes difficult to smoothly perform the coating work, and the colored coating layer 3 is peeled off when the secondary product is press-molded, for example, insect repellent coating. This is because the workability of the coating film on the steel sheet is impaired. The dry film thickness of the top layer 4 is 2 to 20 μm.
The reason is that it is impossible to apply the top coating uniformly so that the dry film thickness of the top layer 4 is less than 2 μm in terms of the coating technique, and it becomes difficult to perform uniform coating. When the dry film thickness of the top layer 4 exceeds 20 μm, cracking or bubbling occurs,
This is because it becomes difficult to obtain a suitable coating quality.

When the top layer 4 is formed by the top coating compounded with the insect repellent composed of the compound of the dibasic acid saturated dialkyl ester and the synthetic pyrethroid compound, the compatibility of the two compounds with the top coating and the heat Due to its excellent stability, it is possible to obtain an insect-repellent coated steel sheet which can prevent thermal decomposition of the insect repellent due to seizure of the coating film and has a high medicinal effect and a reliable pest repellent effect. It is also advantageous in that the pest repellent effect can be synergistically improved. Since the thermal decomposition and alteration of the insect repellent in the drying step can be eliminated, the top layer 4 can be dried by the drying heat at a higher temperature.
Therefore, it is not necessary to slow down the feed rate of the base material steel sheet and perform a slow drying process, and it is possible to efficiently manufacture a coated steel sheet having an insect repellent function.

When the dry film thickness of the top layer 4 is set to 5 to 12 μm, a top layer having a uniform thickness can be surely formed, and a coating film which is smooth and has excellent glitter can be formed and insect repellent. The pest repellent effect can be improved while suppressing the amount of the agent used.

[0012]

EXAMPLE As shown in FIGS. 1 and 2, the insect-repellent coated steel sheet is coated with a primer on one surface of the base material steel sheet 1 whose surface is subjected to chromate treatment, and is dried and solidified to form a primer layer 2. A step of applying a colored paint on the surface of the primer layer 2 and baking and drying to form a colored coating layer 3; and a step of applying a top paint containing an insect repellent on the surface of the colored coating layer 3 and baking and drying. It is manufactured through a step of forming the top layer 4.

As the base steel sheet 1, a cold rolled steel sheet, a galvanized steel sheet, a zinc-aluminum plated steel sheet, a stainless steel sheet or the like can be used. In many cases, the primer layer 2 is coated with a rust preventive pigment containing one or more of strontium chromate, calcium chromate, and barium chromate. The amount of the rust preventive pigment blended is 5 to 60 parts by weight with respect to 100 parts by weight of the primer, and the dry film thickness of the primer layer 2 is 3 to 10 μm. The primer layer 2 may be omitted depending on the application of the insect-repellent coated steel sheet.

As the colored paint for forming the colored coating layer 3, polyester paint, urethane paint, epoxy-
A coating material such as a polyester coating material or an acrylic coating material is applied to the surface of the primer layer 2 and then baked and dried at a plate temperature of 170 to 260 ° C. Also, by setting the baking time to 10 to 200 seconds,
It can accelerate the cross-linking of paints and improve processability and weather resistance. The dried film thickness of the colored coating film layer 3 is preferably 7 to 40 μm. When the dry film thickness of the colored coating film layer 3 is less than 7 μm, the coloring masking property of the colored coating film layer 3 is lost and the primer layer 2 can be seen through. Further, if the dry film thickness of the colored coating film layer 3 exceeds 40 μm, it becomes difficult to smoothly perform the coating work, and the workability of the coating film of the insect-proof coated steel sheet is impaired when the secondary product is press-molded. Because it is done. There is also a disadvantage that the cost is high because a large amount of coloring paint is used.

The top paint is either a colored paint of the same color as the colored coating layer 3 or a clear paint, and is mixed with an insect repellent to prepare the top paint. The insect repellent is obtained by mixing dibasic acid saturated dialkyl ester as a main component with a small amount of a synthetic pyrethroid compound, and by adding the pyrethroid compound, the insect repellent effect can be synergistically improved. The compounding ratio is 1 to 5 parts by weight of the pyrethroid compound with respect to 100 parts by weight of the dibasic acid saturated dialkyl ester.
0 parts by weight. The insect repellent is 0.1 to 4.0 parts by weight, relative to 100 parts by weight of the colored paint or the clear paint.
More preferably, it is added in an amount of 0.3 to 1.0 part by weight. If the content of the insect repellent is less than 0.1 part by weight, the pest repellent effect is difficult to be exhibited. On the other hand, if the content of the insect repellent exceeds 4.0 parts by weight, the gloss of the top layer 4 after baking and drying becomes dull, and it becomes difficult to form a coating film having a smooth and uniform thickness. As the amount of the insect repellent compounded increases, the manufacturing cost of the insect-coated steel sheet increases, but the pest repellent effect cannot be obtained in proportion to the increase in the cost.

After applying the top coating to the colored coating layer 3,
The top layer 4 is formed by baking and drying at a plate temperature of 180 to 260 ° C. More preferably, the applied top paint is baked and dried at a plate temperature of 210 to 240 ° C. to form the top layer 4. When the plate temperature is less than 180 ° C., the coating film cannot be sufficiently cured, the adhesion to the colored coating film layer 3 is reduced, blocking is likely to occur, and the solvent resistance is also reduced. . Baking temperature is 2
If the temperature exceeds 60 ° C, the insect repellent is thermally decomposed to lower the drug effect and the coating film is discolored. The dry film thickness of the top layer 4 is 2 to 2
The thickness is 0 μm, and more preferably 5 to 12 μm.
It is difficult in terms of coating technology to apply the top coating uniformly so that the dry film thickness of the top layer 4 is less than 2 μm, and when the dry film thickness of the top layer 4 exceeds 20 μm, armpits and bubbles are generated. Is.

By forming the colored coating layer 3 as described above and then forming the thin top layer 4 containing the insect repellent on the surface thereof, the pest repellent effect can be obtained while reducing the compounding amount of the insect repellent to the top paint. It can be reliably exhibited, and the production cost of the insect-repellent coated steel sheet can be reduced by the amount that the amount of insect-repellent used can be reduced. Since the top layer 4 is formed by using a colored paint or a clear paint having a color similar to that of the colored coating layer 3, the design effect of the colored coating layer 3 is prevented from being impaired by the top layer 4, and the coated steel sheet is protected from pests. A repellent function can be added. Since the synthetic pyrethroid compound and the dibasic acid saturated dialkyl ester have excellent compatibility with the top coating material and also have excellent thermal stability against drying heat, thermal decomposition due to drying heat can be prevented. As a result, the baking and drying of the top layer 4 can be performed at a high temperature, so that it is possible to efficiently manufacture the insect-repellent coated steel sheet without the need to reduce the feed rate of the base material steel sheet 1.

(Test Example) Five kinds of test pieces were prepared and tested in order to evaluate the physical properties and appearance of the insect-repellent coated steel sheet when the compounding amount of the insect-repellent agent with respect to the top paint was changed. As the base material steel plate 1, a galvanized steel plate having a plate thickness of 0.45 mm was prepared, and a polyester-based coating material was applied to both front and back surfaces thereof and dried and solidified to form a primer layer 2. The dry film thickness of the primer layer 2 was 8 μm. A polyester-based white paint was applied to the surface of the primer layer 2 and dried and solidified to form a colored coating film layer 3. The dry film thickness of the colored coating film layer 3 was 23 μm. A polyester-based clear paint containing an insect repellent was applied to the surface of the colored coating film layer 3 and dried and solidified to form the top layer 4. The temperature for baking and drying is 230 ℃,
The dry film thickness was 10 μm. The compounding amounts of the insect repellents of the five test pieces were different, and were 0, 0.3, 0.5, 1.0 and 5.0 parts by weight with respect to 100 parts by weight of the top coating amount.

The chart shown in FIG. 3 shows the comparative evaluation of the physical properties and appearance of the above-mentioned 5 kinds of test pieces. Evaluation of appearance is
The appearance of the coating film when the top layer 4 was formed with a roll coater was visually determined, and its coating workability was also confirmed. In order to confirm the workability, the presence or absence of peeling of the coating film was visually confirmed when each test piece was bent 180 degrees. Each test piece was immersed in a 3% hydrochloric acid aqueous solution for 24 hours to confirm the acid resistance. Similarly, each test piece was immersed in a 3% aqueous sodium hydroxide solution for 24 hours to confirm the alkali resistance. As can be seen from the chart, each test piece containing the insect repellent in an amount of 1.0 parts by weight or less had no problem in workability during painting and pressing and was excellent in acid resistance and alkali resistance. However, the test piece containing 5.0 parts by weight of the insect repellent causes streaks and scratches at the time of coating, and the test piece is 18
The coating film peeled when it was bent at 0 degrees. Further, a part of the coating film was peeled off by the hydrochloric acid aqueous solution, and a part of the coating film was swollen by the sodium hydroxide aqueous solution. From these results, the compounding amount of the insect repellent was set to 0.1 to 4.0 parts by weight.

In order to confirm the chemical effect of the insect-repellent coated steel sheet, the pest repellent effect was confirmed using the same five kinds of test pieces as described above. As shown in FIG. 4, the height is 20 cm and the height is 15 cm. Width 26
cm, paper container 1 with resin coating on the inner surface
0 was prepared, and a test shelter 11 composed of the above-mentioned test piece and a control shelter 12 for comparison were arranged inside thereof. The test shelter 11 is composed of a square test piece 13 having a side length of 7 cm, a cover 14 made of a veneer plate having the same shape and size as the test piece 13, and a spacer 15 fixed around the four sides of the cover 14. The piece 13 and the cover 14 are opposed to each other with a gap of 5 mm, and the entrances and exits 16 are opened in each of the four surroundings. The test shelter 11 is a test piece 13
It was installed in the container 10 with the bottom of the container. The control shelter 12 basically has the same structure as the test shelter 11, except that a bottom plate 17 made of a veneer plate is used instead of the test piece 13. Both shelters 11 and 12 in the container 10
An absorbent cotton 18 impregnated with water and a feed 19 were arranged between the two so that the test insects (imagos of German cockroaches) could freely ingest the feed.

With the above-described test preparations in place, 20 test worms were released into the container 10 and, after 24 hours, the number of test worms entering each shelter 11.12 was counted. The test was repeated twice in consideration of differences in environmental conditions such as ambient temperature and humidity and variations due to individual differences.
And the total number of sample insects in the sample shelter 11 thus obtained,
The percentage was calculated from the reciprocal of the ratio of the total number of test insects in the control shelter 12 to the pest repellent rate. When the total number of test insects in the test shelter 11 exceeds the total number of test insects in the control shelter 12, there is no pest repellent effect and the repelling rate is 0%. did. Figure 5
The chart shows the results. As can be seen from this chart, the pest repellent rate of the test piece 1 containing no insect repellent is naturally 0.
%, But the pest repellent rate of test pieces 2 to 5 was 58 to 83
A good result was obtained.

In addition to the above, the top layer 4 may optionally contain a potency enhancer, an antioxidant, an ultraviolet absorber, a colorant,
Plasticizers, surfactants, antibacterial agents, antifungal agents, etc. can be used in combination.

[Brief description of drawings]

FIG. 1 is a sectional view of an insect-repellent coated steel sheet.

FIG. 2 is an explanatory view showing a procedure for manufacturing an insect-repellent coated steel sheet.

FIG. 3 is a table showing the results of comparison of the properties of insect-coated steel sheets.

FIG. 4 is a plan view of a test tool for drug efficacy confirmation and a perspective view of a shelter.

FIG. 5 is a chart showing the results of a drug efficacy confirmation test.

[Explanation of symbols]

1 Base material steel plate 2 Primer layer 3 Colored coating layer 4 top layer

Continued front page    F-term (reference) 4D075 AE03 AE27 CA45 DA06 DB02                       DB04 DB05 DB07 DC38 EA05                       EA43 EB35 EC07                 4F100 AB03A AC00 AH02C AH02H                       AH04C AH04H AK01B AK01C                       AK41 BA03 BA07 CA12C                       JB01 JK06 JL10B JL10C                       JN01C YY00B YY00C                 4H011 AC02 BA06 BB06 BB15 BC19                       DA04 DD05 DH04 DH05

Claims (3)

[Claims] 1. An insect-repellent coated steel sheet obtained by forming a colored coating film layer 3 on the surface of a base material steel plate 1 and applying a top layer 4 on the surface of the colored coating film layer 3. A top coating obtained by blending 0.1 to 4.0 parts by weight of an insect repellent with 100 parts by weight of a coating having a color or a color similar to that of the coating layer 3 is applied to the surface of the colored coating layer 3. Top layer 4
Is formed, the dry film thickness of the colored coating layer 3 is 7 to 40 μm, and the top layer 4 is formed.
The insect-proof coated steel sheet having a dry film thickness of 2 to 20 μm. 2. The insect-repellent coated steel sheet according to claim 1, wherein the insect-repellent agent comprises a compounding agent of a compound composed of a dibasic acid saturated dialkyl ester and a synthetic pyrethroid compound. 3. The insect-proof coated steel sheet according to claim 1, wherein the dry film thickness of the top layer 4 is 5 to 12 μm.