JP3316475B2 - Anti-rust paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust preventive paint. More specifically, the invention of this application is effective as a rust-preventive paint for in-line inner surface coating in the production process of agricultural steel pipes, is capable of thick film coating, and is effective in suppressing the occurrence of armpits during high-temperature baking. It relates to a new antirust paint.

[0002]

2. Description of the Related Art Conventionally, as a rust-preventive paint for in-line inner surface coating during the production of electric conduits and agricultural steel pipes, an epoxy resin has been used as a main component.
It is instantaneous (2 to 15
(Seconds) are known that can cure the coating.

[0003] Then, regarding this conventional rust preventive paint,
As its composition, the epoxy resin is a main component, further, or alkylene head resins, acrylic resins, the resin component, also those which are constituted by a solvent such as methyl ethyl ketone are known, such as methyl silicone resin.

[0004]

However, in the case of a conventionally known ultra-high temperature instant bake type rust preventive paint, 400 to 50 seconds after the paint is applied by airless spray 5 to 45 seconds.
About 2-5 µm for baking at an ultra-high temperature of 0 ° C
However, there is a restriction that only a coating film having a small thickness can be formed. For this reason, there remains a problem in terms of the effect of rust prevention and its long-lasting effect.

[0005] limitations of the thickness of such a coating is not volatilization amount of anticorrosive coatings are also due to less than 40% and less, the conventional paints, non volatilization in terms of paintability It is difficult to increase the amount, and when the amount of application is increased, there is a problem in that the rust is generated and the rust prevention effect is deteriorated. Therefore,
In the invention of this application, the conventional problems as described above are solved, and even a non-diluted coating by airless spray can form a thick film of, for example, 5 to 10 μm. 400 to 500 ° C after 5 to 45 seconds
It is an object of the present invention to provide an improved new rust-preventive paint that can form a rust-preventive coating by suppressing baking at the time of coating baking by baking at an ultra-high temperature for 2 to 15 seconds. .

[0006]

Means for Solving the Problems The present invention solves the above-mentioned problems. First, an epoxy resin as a main component is used at an extremely high temperature of 400 to 500 ° C. for 2 to 15 seconds.
An ultra-high temperature instant bake type rust preventive paint that is baked for a while
Relative to 100 parts by weight of the epoxy resin is blended is phenylmethyl silicone resin of 15 to 90 parts by weight, the paint non volatilization content provides anticorrosive coating, characterized in that it accounts for from 42 to 90 wt%. Secondly, the invention of this application is characterized in that glycidyl ether as a reactive diluent is 2 to 5
The rust-preventive paint is provided in an amount of 0% by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application has the features as described above, and embodiments thereof will be described below. First, in the invention of this application, similar to the ultra-high-temperature flash baking type anticorrosive paint conventionally known, its composition is mainly composed of epoxy resin. An alkyd resin, an acrylic resin, a phenol resin, or the like can be appropriately blended with the epoxy resin as the main component, as in the related art. The following is an example of a typical resin composition by weight ratio.

Liquid epoxy resin 100 Alkyd resin 20 to 50 Acrylic resin 2 to 10 These resin compositions are prepared by adding a solvent such as methyl ethyl ketone in an amount of about 20 to 40 parts by weight with respect to 100 parts by weight. It can be.

[0009] In the above compositional composition, in the invention of this application, a phenylmethyl silicone resin is blended in order to obtain a rust preventive paint having excellent characteristics. In the past, attempts have been made to incorporate a methyl silicone resin, but this methyl silicone resin has no phenyl group in the silicone polymer molecule, and is essentially different from the phenyl methyl silicone resin in the present invention. Are different. The coating properties of the conventional methylsilicone resin and the phenylmethylsilicone resin of the present invention are greatly different from each other.

The rust preventive paint of the present invention containing a phenylmethylsilicone resin has a much thicker film than a conventional paint film having a thickness of 2 to 5 μm.
For example, it is possible to form a coating film having a thickness of 5 to 10 μm, which is two to three times as large as that of the conventional art, while suppressing the occurrence of wrinkles during high temperature baking. Moreover, it enables airless spray coating without dilution. This is the conventional paint had a non volatilizing <br/> onset content is 40% or less, which means that you can higher proportion of non-volatilization component in the coating of the present invention.

In the case of the conventional methyl silicone resin compound, the heat resistance of the coating material is low, and a baking film at an extremely high temperature of 400 to 500 ° C. cannot form a clear coating film. By the compounding, a thick coating film is formed as having a uniform density, and the heat resistance of the coating material is improved.
In the rust preventive paint of the present invention, there is no effect due to the blending of the conventionally known methyl silicone resin, and the blending of the phenyl methyl silicone resin is an essential feature.

[0012] For phenylmethyl silicone resin, which is also commercially available, linear, or may be any branched-chain, but in the present invention, straight phenylmethyl silicone resin is more preferably Used as The molecular weight distribution may be selected in consideration of the effects of the present invention. The amount of the phenylmethylsilicone resin is preferably 15 to 90 parts by weight with respect to 100 parts by weight of the epoxy resin in terms of the weight ratio to the epoxy resin as the main component. More preferably, it is 25 to 90 parts by weight. If the amount is less than 15 parts by weight, or if it exceeds 90 parts by weight, the intended effect of the present invention is hardly obtained. In particular, when the amount is less than 15 parts by weight, formation of a coating film becomes difficult due to foaming.

[0013] In the anticorrosive coating of the present invention, including the phenylmethyl silicone resin, the coating material non-volatilization min 42
Suitably, it is set to 90% by weight. More preferably, it is 60 to 90% by weight. The proportion of non-volatilization fraction can be controlled by the blending amount of the epoxy resin or phenyl methyl silicone resin. Conventionally 40%
Proportion of non-volatilization component which has been constrained in the following may be a higher percentage in this invention. That is, according to the present invention, a high solid type rust preventive paint is provided.

[0014] When non volatilization amount is less than 42%, the desired effect is hardly sufficiently obtained in the present invention, when more than 90% of handling operation becomes difficult as in paints. The rust preventive paint of the present invention may contain a reactive diluent. For example, various reactive diluents such as glycidyl ether and glycidyl ether / ester are exemplified.

The amount of the compound is 60
% By weight or less, and 2 to 50% by weight when a more suitable glycidyl ether is used as a reaction diluent,
More preferably, a range of 5 to 30% by weight is considered. These reaction diluent, while maintaining a high non-volatilization component, there is more effectively suppressed action popping generation during coating baking.

Then, examples are shown below, and the invention of this application will be described in more detail. Of course, the invention of this application is not limited to the following examples.

[0017]

EXAMPLES In the following Examples and Comparative Examples, airless spray coating was carried out without dilution and baked after coating to form a coating film having a thickness of about 8 μm. (Examples 1 to 3) (Comparative Examples 1 to 4) The following composition (parts by weight): 100 parts by weight of a resin composition composed of liquid epoxy resin 70 alkyd resin 25 acrylic resin 5 methyl ethyl ketone 25, and phenyl methyl silicone Resin (Shin-Etsu Chemical Co., Ltd .: KR-15)
5) was added at the ratio shown in Table 1 to prepare a clear paint.

This clear paint is applied to a steel plate having a thickness of 0.5 mm and heated instantaneously to 450 to 500 ° C.
Bake for seconds. The state and heat reduction of the formed coating film were evaluated. The results are also shown in Table 1. For comparison, when the phenylmethylsilicone resin was not blended and when the methylsilicone resin was blended instead of the phenylmethylsilicone resin, the state of the coating film and the decrease due to heat were similarly evaluated, and the results are shown in the table. 1 is shown.

[0019]

[Table 1]

As is clear from the results shown in Table 1, in the examples of the present invention, foaming is suppressed and a good coating film is obtained, and the decrease in coating film due to baking is also suppressed. In the comparative example, it can be seen that the influence of foaming is large and the heat loss is large. In addition, the dried coating film in the case of the example is a salt water spray test 72
It was confirmed that it had rust-proofing ability that passed the time. on the other hand,
In the case of the comparative example, there was a problem in rust prevention. (Examples 4 to 8) The following composition (parts by weight): 100 parts by weight of a liquid epoxy resin 60 alkyd resin 22 acrylic resin 4 phenylmethylsilicone resin 12 to 20 (Shin-Etsu Chemical Co., Ltd .: KR-155) against part, glycidyl ether reactive diluent was added in an amount shown in Table 2 with ethyl ketone 0-30 parts was not volatilized Hatsubun (theoretical) proportions clear paint of Table 2.

This clear paint was applied to a steel plate having a thickness of 0.5 mm, heated instantaneously to 450 to 500 ° C., and baked for 10 seconds. The state of the obtained coating film was evaluated. The results are shown in Table 2. In addition, a coating film in which only methyl ethyl ketone was added without adding a reactive diluent was similarly evaluated. The results are also shown in Table 2.

[0022]

[Table 2]

It can be seen that foaming is effectively suppressed by the addition of the reactive diluent.

[0024]

As described in detail above, the invention of this application enables thick film coating which is useful as an anticorrosive paint for in-line inner surface coating in the production process of agricultural steel pipes, and which can be used for baking at high temperature baking. A rust-preventive paint which is effective in suppressing the generation and has excellent rust-preventive power is provided.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-132165 (JP, A) JP-A-10-183383 (JP, A) JP-A-63-176894 (JP, A) JP-A-3- 275348 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 163/00-163/10 C09D 5/08 C09D 183/04-183/08

Claims (2)

(57) [Claims] 1. An epoxy resin comprising 400 to 5 as a main component .
UHT instantaneous is baked 2-15 seconds at ultra high temperature 00 ° C.
It is between baking-type anticorrosive paint, with respect to 100 parts by weight of the epoxy resin, characterized in that 15 to 90 parts by weight of phenyl methyl silicone resin is blended, the coating non-volatilization fraction accounts for 42-90 wt% And anti-rust paint. 2. The rust preventive paint according to claim 1, wherein glycidyl ether as a reactive diluent is blended at a ratio of 2 to 50% by weight.