JPH08206598A - Formation of silicone coating film - Google Patents

Abstract

PURPOSE: To provide a forming method of a silicone coating film excellent in adhesions of an intermediate coating film to a corrosion resistant coating film and a finish coating film and excellent in durability and weatherability. CONSTITUTION: A normal temp. dry type coating composition containing 30-100wt.% thermoplastic polyamide having 80-150 deg.C softening point, an acid value of <=10 and an amine value of <=20 per total resin components and 0-70wt.% hard resin par total resin components are applied on a material to be coated without forming the corrosion resistant coating film or after forming the corrosion resistant coating film, then, a silicone rubber based finish coating is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a silicone coating film which is excellent in adhesion between an intermediate coating film, an anticorrosive coating film and a silicone rubber-based top coating film and which is excellent in durability and weather resistance.

[0002]

BACKGROUND OF THE INVENTION Industrial water systems, water intake facilities such as nuclear power plants, marine structures, ships and other submerged surfaces are protected by a top coat paint to prevent them from being contaminated by adherent organisms in the sea. Dirty paint is applied. Also, ships,
Outdoor communication equipment and the like are coated with a top-coat paint that forms an anti-icing coating film for the purpose of preventing icing. Furthermore,
Buildings such as telephone poles and telephone boxes are coated with a top-coat paint that forms a low-adhesion surface for the purpose of preventing outdoor paper sticking.

As a top coat paint which can be used as such an antifouling paint, an anti-icing paint, a paper sticking preventive paint and the like,
In recent years, silicone rubber-based paints containing various kinds of pollution-free silicone oils have begun to be used. In general, such silicone rubber-based paints are often used as, for example, antifouling paints by being directly applied to ordinary anticorrosion coatings and intermediate coatings. However, when a coating film is formed in this way, the adhesion of the top coating film is poor,
There was a problem with durability in seawater and weather resistance at the submerged boundary that was washed by seawater.

In order to overcome these drawbacks, Japanese Patent Publication No.
Japanese Patent Application Laid-Open No. 9-48065 discloses a technique of forming a coating film by using an intermediate coating material for coating silicone rubber, which is a conventional anticorrosion coating material mixed with silicone rubber. Further, JP-A-3-258876 discloses a technique for forming a coating film by using a silicone-modified epoxy resin obtained by reacting dimethylpolysiloxane with an epoxy resin as an intermediate coating material for coating silicone rubber. There is.

[0005]

However, in such a method, the adhesion between the resulting intermediate coating film and the silicone rubber-based coating film as the top coating film is insufficient, and further,
In the case of using the silicone rubber-coated intermediate coating for mixing silicone rubber, at the boundary surface between the coating of this intermediate coating and the anticorrosion coating on the inside, blistering of the coating,
Peeling and the like occurred, which adversely affected the durability and weather resistance of the entire coating system.

In view of the above situation, the present invention is a method for forming a silicone coating film which is excellent in adhesion between an intermediate coating film, an anticorrosive coating film and a silicone rubber-based top coating film and which is excellent in durability and weather resistance. It is intended to provide.

[0007]

The gist of the present invention is, as a method for forming a silicone coating film, a softening point of 80 with or without forming an anticorrosion coating film on an object to be coated.
To 150 ° C., an acid value of 10 or less, and an amine value of 20 or less, the thermoplastic polyamide is 30 to 100% by weight of all resin components,
Further, a room temperature dry type coating composition containing 0 to 70% by weight of the total resin component of hard resin is applied, and then a silicone rubber-based top coating composition is applied. In the present specification, the "silicone coating film" means a coating film composed of the entire coating system using a silicone rubber-based top coating film as the outermost layer. The present invention is described in detail below.

In the present invention, when the object to be coated is a corrosive material such as steel, a zinc rich paint, a tar epoxy paint, an epoxy anticorrosion paint, a urethane anticorrosion paint or the like is known as necessary. After coating the anticorrosion paint of (1) and drying to form the anticorrosion coating, the intermediate coating is applied and dried, and then the top coating is applied to form the silicone coating. If anticorrosion coating is not required, such as when the surface of the object to be coated is a concrete surface, a known undercoating treatment such as permeation-preventing treatment, anti-floating treatment, and putty filling for smoothing may be performed as necessary. After that, the intermediate coating composition can be applied and dried, and then the top coating composition can be applied to form the silicone coating film.

In the present invention, a room temperature dry type coating composition containing a thermoplastic polyamide is used as the intermediate coating composition. The thermoplastic polyamide contained in the room temperature dry coating composition is a condensate of a polycarboxylic acid and a polyamine and has a softening point of 80 to 150 ° C. and an acid value of 10.
Hereinafter, it is a resin that has an amine value of 20 or less and is solid at room temperature. The molecular weight of the thermoplastic polyamide is 4000 to 1
2000 is preferred.

The thermoplastic polyamide is not particularly limited, and examples thereof include Bar Salon 930 (manufactured by Henkel Hakusui Co., Ltd.), Bar Salon 940 (manufactured by Henkel Hakusui Co., Ltd.), Bar Salon 1117 (manufactured by Henkel Hakusui Co., Ltd.), Bar Salon 112.
9 (manufactured by Henkel Hakusui), Bar Salon 1128 (manufactured by Henkel Hakusui), Bar Salon 1128 (manufactured by Henkel Hakusui), DPXJ50 (manufactured by Henkel Hakusui), DPX80
2 (manufactured by Henkel Hakusui), DPX830 (manufactured by Henkel Hakusui), Sunmide 550-D (manufactured by Sanwa Chemical Co., Ltd.), Sunmide 553 (manufactured by Sanwa Chemical Co., Ltd.), Sunmide X-280.
0 (manufactured by Sanwa Chemical Co., Ltd.), HT140E (manufactured by Sanwa Chemical Co., Ltd.) and the like. These may be used alone or in combination of two or more.

The room temperature dry coating composition used in the present invention may further contain a hard resin. The hard resin is not particularly limited as long as it has a softening point of about 100 ° C. and is solid at room temperature.
Alkylphenol resin, coumarone indene resin, rosin ester, polymerized rosin, terpene resin, ester gum, phenol resin, epoxy resin, and the like, and epoxy-modified resin such as epoxy ester resin, epoxy acrylate resin, and epoxy polyol resin. Etc. can be mentioned. These may be used alone or in combination of two or more.

When the above hard resin is blended,
The blending amount of the thermoplastic polyamide in the room temperature dry coating composition used as an intermediate coating is 30% by weight or more of the resin component, and the blending amount of the hard resin is 70% by weight or less of the resin component. is there. If the thermoplastic polyamide is less than 30% by weight of the resin component and the hard resin is more than 70% by weight of the resin component, the flexibility of the dry coating film is lost, which causes poor adhesion. To be done. Preferably, the thermoplastic polyamide is 50 to 95% by weight of the resin component, and the hard resin is 50 to 5% by weight of the resin component.

In the above room temperature dry type coating composition used as an intermediate coating composition, the resin vehicle may be composed only of the above thermoplastic polyamide, or may be composed of the above thermoplastic polyamide and the above hard resin. However, in any case, the amount of the resin vehicle is preferably 3 to 80% by weight of the room temperature dry coating composition. If it is less than 3% by weight, the coating film-forming property is deteriorated, and if it exceeds 80% by weight, the coating property and sag property of the coating composition are deteriorated, which is not preferable. More preferably 10-5
0% by weight.

The room temperature dry coating composition used in the present invention may contain an anticorrosive pigment for the purpose of imparting anticorrosion performance to itself. The rust preventive pigment is not particularly limited, for example, red lead, cyanamide lead, cyanamide zinc, zinc chromate, strontium chromate,
Examples thereof include metal compounds such as zinc phosphate, aluminum tripolyphosphate, tribasic lead sulfate, lead suboxide, calcium zinc cyanamide, aluminum molybdate, and basic lead chromate.These may be arbitrarily selected. It can be blended.

When preparing the above room temperature dry type coating composition used in the present invention, a solvent, a coloring pigment, an extender pigment, a viscosity modifier and the like which are usually used in the coating composition can be added. The above-mentioned room temperature dry type coating composition used in the present invention can be prepared by a known method in the technical field of coating production.

In the present invention, the room temperature dry type coating composition is applied as an intermediate coating, and then a silicone rubber type top coating is applied as a top coating. As the above-mentioned silicone rubber-based top coating composition, a silicone rubber-based coating composition containing a reaction-curable silicone rubber as a main resin and various silicone oils as essential components is preferable. The above-mentioned reaction-curable silicone rubber is a liquid composition obtained by adding a polyorganosiloxane having a crosslinkable reactive group, a silane compound as a crosslinking agent, a reaction catalyst and, if necessary, silica in the silicone rubber-based coating composition. It exists as a mixture, and has the property of undergoing a cross-linking reaction to form a coating film when applied.

The above silicone oil is a liquid silicone oil having a polyorganosiloxane as a main skeleton, and one having only a methyl group as an organo group is called dimethyl silicone oil, and a part of the methyl group is a phenyl group, Various modified silicone oils substituted with vinyl groups, alkyl groups, aralkyl groups, amino groups, carboxyl groups, epoxy groups, hydroxyl groups, polyoxyalkylene groups, etc. are also known. The silicone rubber-based coating composition may contain any of these silicone oils. In some cases, the silicone rubber-based coating composition may be a so-called two-component coating composition in which a reaction catalyst and a crosslinking catalyst are first separated and then mixed with a resin immediately before coating.

Examples of such a silicone rubber-based coating composition include a silicone rubber-silicone oil mixture obtained by low-temperature curing an oligomeric silicone rubber having a hydroxyl terminal group in the presence of silicone oil; Composition containing a mixture of petrolatum or liquid paraffin and silicone oil; reaction-curable silicone resin and silicone resin containing polar group such as amino group, carboxyl group, epoxy group, polyethylene glycol group A composition etc. can be mentioned.

In the present invention, the room temperature dry type coating composition and the silicone rubber-based top coating composition are coated by a known coating method such as airless coating, air spray coating, roller coating, brush coating, etc. A film can be formed. The coating film thickness of the room temperature dry type coating composition and the silicone rubber-based top coating composition can be a desired and appropriate value depending on the application.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Preparation of intermediate coating composition DPX-802 varnish 45.0% by weight titanium dioxide 10.0% by weight talc 15.0% by weight clay 15.0% by weight xylol 10.0% by weight isopropyl alcohol 5. 0 wt% The above-mentioned blending components were made into a paint using an SG disperser to prepare an intermediate paint. In the above formulation, DPX-802 varnish is a 50% (xylol / isopropyl alcohol = 3/1) solution of a polyamide resin having an amine value of 10, an acid value of 3> and a softening point of 90 ° C., manufactured by Henkel Hakusui.

Preparation of silicone rubber antifouling paint Silicone rubber KE-45TS 60.0% by weight Silicone oil KF-96 15.0% by weight Silicone oil KF-53 15.0% by weight Xylol 10.0% by weight The components were mixed with a homomixer to prepare a test silicone rubber antifouling paint. Silicone rubber KE-45TS is a room temperature reaction curable deoxime type silicone rubber varnish manufactured by Shin-Etsu Chemical Co., Ltd. (volatile content 50%).
Is. Silicone oil KF-96 represents Shin-Etsu Chemical Co., Ltd. polydimethylsiloxane oil, and silicone oil KF-53 represents Shin-Etsu Chemical Co., Ltd. polymethylphenylsiloxane oil.

The resulting intermediate coating composition was applied to 15 cm × 10 c
An m × 1.6 mm test steel plate was coated with an airless coating machine so as to have a dry film thickness of about 40 μm, and air-dried for 3 days. In addition, the test steel plate had a tar-epoxy anticorrosive paint (Epotal BO,
A paint which was manufactured by Nippon Paint Co., Ltd., JIS K 5664 (1st type) and was air-dried for 3 days was used. A test steel sheet coated with an intermediate coating composition and dried was further coated with the obtained silicone rubber antifouling coating composition for a test as a top coating composition with an airless coating machine so that the dry film thickness was about 100 μm. A test steel plate coated with an antifouling coating was prepared by air-drying for 3 days.

Performance test After making an antifouling coating on the prepared test steel plate with an X-shaped cut by a cutter blade so as to reach the tar epoxy anticorrosion coating film, it is under the sea surface with an undersea raft off Tamano City, Okayama Prefecture. About 5
After being immersed in a depth of 0 cm, the adhesion of the intermediate coating film to the tar epoxy anticorrosion coating film and the topcoat silicone rubber-based antifouling coating film, and the durability of the entire coating film were evaluated. The results are shown in Table 1.
It was shown to. The evaluation criteria are as follows. ◯: No peeling or blistering near the cut site Δ: Peeling or blistering near the cut site X: Peeling or blistering outside the cut site

Example 2 An antifouling coated steel sheet for test was prepared, tested and evaluated in the same manner as in Example 1 except that an intermediate coating composition was produced using the following ingredients. The results are shown in Table 1. Formulation DPX-802 varnish 30.0 wt% Hitanol 1002 varnish 15.0 wt% Titanium dioxide 10.0 wt% Talc 15.0 wt% Clay 15.0 wt% Xylol 10.0 wt% Isopropyl alcohol 5.0 wt% In the above formulation, Hitanol 1002 varnish is a 50% (xylol / isopropyl alcohol = 3/1) solution of alkylphenol resin manufactured by Hitachi Chemical.

Example 3 An antifouling paint-coated test steel sheet was prepared, tested and evaluated in the same manner as in Example 1 except that an intermediate coating composition was produced using the following ingredients. The results are shown in Table 1. Formulation DPX-802 varnish 14.0 wt% Hitanol 1002 varnish 31.0 wt% Titanium dioxide 10.0 wt% Talc 15.0 wt% Clay 15.0 wt% Xylol 10.0 wt% Isopropyl alcohol 5.0 wt%

Example 4 A test steel sheet coated with an antifouling coating was prepared, tested and evaluated in the same manner as in Example 1 except that an intermediate coating composition was produced using the following ingredients. The results are shown in Table 1. Formulation DPX-802 varnish 22.5% by weight Hitanol 1002 varnish 22.5% by weight Titanium dioxide 10.0% by weight Talc 15.0% by weight Clay 15.0% by weight Xylol 10.0% by weight Isopropyl alcohol 5.0% by weight

Example 5 An antifouling coating steel sheet for test was prepared, tested and evaluated in the same manner as in Example 1 except that an intermediate coating composition was produced using the following ingredients. The results are shown in Table 1. Formulation DPX-802 varnish 42.0 wt% Hitanol 1002 varnish 3.0 wt% Titanium dioxide 10.0 wt% Talc 15.0 wt% Clay 15.0 wt% Xylol 10.0 wt% Isopropyl alcohol 5.0 wt%

Comparative Example 1 Example 1 was repeated except that the following formulation (A) and formulation (B) were placed in a container at a weight ratio of 80:20 and thoroughly mixed with a mixer to produce an intermediate coating composition. Similarly, a test steel plate coated with an antifouling coating was prepared, tested, and evaluated. The results are shown in Table 1. Formulation (A) ES-1002T 40.0 wt% Titanium dioxide 15.0 wt% Precipitating barium sulfate 15.0 wt% Graphite 10.0 wt% Talc 10.0 wt% Bentonite 1.0 wt% Xylol 7.0 % By weight Cellosolve acetate 2.0% by weight Formulation (B) Sanmide X-2800 50.0% by weight Toluol 30.0% by weight n-butanol 10.0% by weight Methylisobutylketone 10.0% by weight ES- in the above formulation 1002T is a silicone-modified epoxy resin varnish manufactured by Shin-Etsu Chemical Co., Ltd., and has a bisphenol A type epoxy resin of about 70 with an epoxy equivalent of about 600.
% And about 30% of dimethylpolysiloxane, the solid content is 60%. Sunmide X-28
00 is a polyamide resin varnish manufactured by Sanwa Chemical Industry Co., Ltd., having a solid content of 70%, a polyamide adduct system, and an active hydrogen equivalent of about 150.

[0030]

[Table 1]

According to the examples, the adhesion of the coating film of the intermediate coating composition is excellent, there is no blistering or peeling at the interface between the anticorrosion coating film and the silicone rubber-based top coating film, and the silicone is excellent in durability and weather resistance. It was found that a rubber antifouling coating film can be formed.

[0032]

According to the present invention, an intermediate coating film and an anticorrosion coating film,
It is possible to provide a method for forming a silicone coating film which has excellent adhesion to a silicone rubber-based top coating film and excellent durability and weather resistance.

Claims (2)

[Claims] 1. A softening point of 80 to 150 ° C. without forming an anticorrosion coating film on a coating object, or after forming an anticorrosion coating film,
A room temperature dry coating composition comprising a thermoplastic polyamide having an acid value of 10 or less and an amine value of 20 or less in an amount of 30 to 100% by weight of all resin components, and a hard resin in an amount of 0 to 70% by weight of all resin components. A method for forming a silicone coating film, which comprises coating and then applying a silicone rubber-based top coating material. 2. The method for forming a silicone coating film according to claim 1, wherein the silicone rubber-based top coating material is a silicone rubber-based top coating material containing a reaction-curable silicone rubber composition and silicone oil.