JP2768808B2 - Resin composition for zinc rich paint - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition for inorganic zinc-rich paint.

[Prior art] Zinc-rich paint containing sub-powder as an anti-rust pigment generally includes organic zinc-rich paint using an epoxy resin or the like and inorganic zinc-rich paint using an alkyl silicate hydrolysis-condensation resin as a binder. is there. Inorganic zinc-rich paint has excellent drying, heat resistance, durability, and anti-corrosion performance. Widely used for large steel structures such as tanks, plants, and offshore structures.

When using inorganic zinc-rich paint as a primary rust preventive paint in a thin film, reduce the amount of sub-powder due to hygienic problems due to the generation of zinc fume during welding fusing and the problem of overcoat selectivity that alkyd paint cannot be overcoated. Is desired. However, when the amount of sub-powder is reduced, the coating film becomes hard and brittle due to the characteristics of the silicate-based resin, and the substrate adhesion is reduced, and the adhesion at a high temperature heated portion such as the welding back surface or the strain relief back surface is particularly poor. . On the other hand, when used in a thick-film anticorrosion paint, the longer the mixing ratio of the sub-powder and the greater the film thickness, the more advantageous the long-term anticorrosion property. However, when the film thickness is increased, cracks are liable to occur due to the characteristics of the silicate resin, and it becomes difficult to form a coating film. in this way,
An inorganic zinc-rich paint using an alkyl silicate hydrolysis-condensation resin as a binder has a limited film-forming ability.

Conventionally, it has been proposed to mix organic components as disclosed in Japanese Patent Application Laid-Open No. 49-1634 to make up for the above drawbacks, but there is a drawback that the advantages such as heat resistance are impaired. Also, JP-A-59-64671 and JP-B-63-289
As disclosed in Japanese Patent Publication No. 42, it has been proposed to use a trifunctional alkyltrialkoxysilane compound as a part of the binder resin. These can improve the film-forming properties without impairing the advantages of inorganic zinc-rich paints such as heat resistance.However, the alkyl groups directly bonded to silicon lower the surface tension of the coating film, so that the topcoat paint can be improved. Poor adhesion.

[Problems to be Solved by the Invention] An object of the present invention is to improve the film-forming properties while maintaining the advantages of inorganic zinc-rich paints such as heat resistance, and to reduce the surface tension of a coating film without causing a decrease in surface tension. Is to provide a good resin composition. Another object of the present invention is to provide an inorganic zinc-rich paint having excellent performance prepared from the resin composition.

[Means for Solving the Problems] The present inventors have conducted intensive studies on trialkoxysilane compounds, and as a result, by specifying a binder resin composition using a trialkoxysilane compound having a certain structure, The inventors have found that there is no decrease in the surface tension of the coating film and no adverse effect on the overcoating property, and the present invention has been completed.

That is, the present invention provides: [Wherein each R ¹ may have the same or different carbon number of 1 to 5
Represents an alkyl group. 100 parts by weight of a mixture of an alkyl silicate and / or a condensate thereof represented by the following formula: and (B) a general formula: [Wherein, R ¹ has the same meaning as described above, and R ² represents a hydrocarbon group having 2 to 5 carbon atoms and having an unsaturated bond. The present invention provides a zinc-rich paint resin composition obtained by simultaneously or separately hydrolyzing 5 to 300 parts by weight of a trialkoxysilane compound represented by the following formula (C) using an acid catalyst.

In the present invention, each alkyl group constituting the alkoxy group of the component (A) and the component (B) blended as the binder raw material
R ¹ is the same or different alkyl group having 1 to 5 carbon atoms, and becomes an alcohol by hydrolysis to be dispersed from the coating film. Therefore, when the number of carbon atoms is 6 or more, drying of the coating film is undesirably slow. In the component (A), specific compounds of the alkyl silicate include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetra-n-butoxysilane. The hydrolysis initial condensate is
It means a mixture of polyalkoxysilane oligomers obtained by hydrolyzing some alkoxy groups of these tetraalkoxysilanes, and examples thereof include ethyl silicate 40 (manufactured by Colcoat) and methyl silicate 51 (manufactured by Colcoat). . Those obtained by hydrolyzing and condensing the component (A) are known as binder resins for inorganic zinc-rich paints. However, as described above, when these are used alone as binders, the mixing amount of the sub-powder is reduced. If the thickness is reduced or applied to a thick film, there is a disadvantage that a good coating film cannot be provided. Therefore, in the present invention, the component (B) is further blended as a binder raw material.

The hydrocarbon group R ² directly bonded to silicon of the component (B) is
It is a hydrocarbon group having 2 to 5 carbon atoms containing an unsaturated bond, and specific examples thereof include alkenyl groups such as vinyl, allyl, propenyl and butadienyl and alkynyl groups such as propargyl. When these unsaturated hydrocarbon groups have 6 or more carbon atoms, they tend to lower the surface tension of the coating film, and the heat resistance of the coating film is impaired. In particular, when the zinc-rich paint to which the present resin composition is applied is used as a primary rust-preventive paint, the coating film is less likely to be burned even in a portion heated at a high temperature such as a welding back surface or a strain relief back surface. Since it is necessary to exhibit film performance, it is preferable that the number of carbon atoms is smaller, and specifically, a vinyl group and an allyl group are preferable.

Specific examples of the component (B) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltributoxysilane, allyltrimethoxysilane, allitriethoxysilane, allyltripropoxysilane, and allyltributoxy. Silane,
Examples thereof include 3-butenyltrimethoxysilane and 2-trimethoxysilylbutadiene. These are known as so-called silane coupling agents. Also, two or more of these components (A) and (B) may be used in combination.

The resin composition of the present invention can be obtained by blending the components (A) and (B) in advance, followed by hydrolysis and condensation under acidic conditions using an acid catalyst (C). The components (A) and (B) may be separately hydrolyzed under acidic conditions using an acid catalyst (C), and then mixed. As the acid catalyst (C), those usually used may be used. For example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and the like;
Organic acids such as acetic acid, formic acid, propionic acid and citric acid can be mentioned, and these can be used alone or in combination of two or more.

As the compounding amount of the component (A) and the component (B), it is preferable to add the component (B) in an amount of 5 to 300 parts by weight, more preferably 10 to 200 parts by weight, based on 100 parts by weight of the component (A). .
If the amount of the component (B) is too small, the film-forming properties of a zinc-rich paint using the present resin composition tend to deteriorate. On the other hand, if the amount is excessive, the drying property of the zinc-rich paint is poor, and the anticorrosion property tends to decrease. The compounding amount may be appropriately adjusted depending on whether the zinc-rich paint using the present resin composition is applied as a primary rust preventive paint or a thick-film long-term anticorrosion system.

In order to form the resin composition of the present invention into a zinc-rich paint, commonly used pigment solvents, additives and the like may be appropriately blended as necessary. As the zinc powder, a normal one, that is, an arbitrary shape having an average particle diameter of 1 to 20μ, for example, a spherical shape or a flake shape may be used, and an amount capable of exhibiting coating film performance, for example, a long term When applied to a heavy-duty anticorrosion system, about 50 to 95% by weight of the total solid content of the coating film may be used. In addition, when used as a primary rust-preventive paint, as described above, zinc fumes are generated so much that there is a problem in hygiene. Therefore, 40 to 70% by weight of the total solid content of the coating film is added. Is preferred. As pigments other than zinc powder, extender pigments used in ordinary rust preventive paints, rust preventive pigments, coloring pigments and the like can be used.Specifically, talc, mica, barium sulfate, clay, calcium carbonate, zinc white, Titanium white, red iron, zinc phosphate,
Examples include aluminum phosphate, barium metaborate, aluminum molybdate, iron phosphide, and the like. Solvent components include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone (ME
K), methyl isobutyl ketone (MIBK), toluene, xylene, and the like, and may be added in an appropriate amount so that coating workability and coating film drying property become appropriate. As additives,
An anti-sagging agent, a lubricant, a reaction accelerator, a color-separation inhibitor and the like, which are usually used, may be added in an appropriate amount depending on the purpose.

A zinc-rich paint using the resin composition of the present invention as a binder is prepared according to a conventional method. For example, the liquid component containing the resin composition of the present invention and the system containing the other powder components may be stored in separate containers, and the two may be mixed immediately before use.
In addition, part or all of the powder component other than the component (eg, zinc powder) that reacts with the resin composition may be dispersed together with the liquid component containing the resin composition, and the mixture may be mixed with the remaining components immediately before use. . For dispersing the liquid crystal component and the powder component, an ordinary dispersing machine such as a roll mill, a sand grind mill, a ball mill or the like may be used. The zinc-rich paint thus obtained may be applied to a steel structure by an ordinary means such as an air spray, an airless spray, a roll coater, and a brush, and dried by natural drying or hot-air drying.

[Effects of the Invention] The present invention is characterized in that a binder resin composition of zinc-rich paint is specified using a trialkoxysilane compound having an unsaturated hydrocarbon group such as the component (B). When a resin composition using such a trialkoxysilane compound having an unsaturated hydrocarbon group is applied to a binder for zinc-rich paint, when a resin composition using an already known alkyltrialkoxysilane compound is applied. In the same way as the film-forming property, it is excellent in heat resistance, but the effect of the present invention is not only that, whereas the conventional alkyl trialkoxysilane compound is disadvantageous to the adhesion to the top coat of the coating film, In the present invention, the coating film has excellent adhesion without lowering the surface tension.

Hereinafter, the present invention will be described specifically with reference to Examples. Parts are by weight unless otherwise indicated.

[Example] Preparation of resin composition Each resin composition was prepared by the following procedure. The amount of the active ingredient in these resin composition solutions is 15% by weight.

(Preparation Example 1) 100 parts of tetraethoxysilane and 20 parts of vinyltrimethoxysilane were dissolved in 122.3 parts of isopropanol, and 21 parts of 0.01 N hydrochloric acid was added dropwise, followed by heating and stirring at 60 ° C for 3 hours to terminate the hydrolysis reaction. Thus, a resin composition solution A was prepared.

(Preparation Example 2) A resin composition solution B was prepared in the same manner as in Preparation Example 1, by dissolving 100 parts of tetraethoxysilane in 75 parts of isopropanol and dropwise adding 17 parts of 0.01 N hydrochloric acid. Separately, 100 parts of vinyltrimethoxysilane was dissolved in 233.4 parts of isopropanol, and 18 parts of 0.01 N hydrochloric acid was added dropwise to prepare a resin composition solution C in the same manner. The components were mixed at the indicated ratios.

(Preparation Example 3) 100 parts of ethyl silicate 40 (manufactured by Colcoat), 200 parts of allyltriethoxysilane, 524.1 of isopropanol
Resin composition solution D was prepared in the same manner as in Preparation Example 1, except for using 50 parts of 0.01 N hydrochloric acid.

(Preparation Example 4) A resin composition solution E was prepared in the same manner as in Preparation Example 1, using 100 parts of tetrabutoxysilane, 40 parts of alritriethoxysilane, 90 parts of isopropanol, and 16.5 parts of 0.01N hydrochloric acid.

(Preparation Example 5) 100 parts of methyl silicate 51 (manufactured by Corcol) and 2-
Resin composition solution F was prepared in the same manner as in Preparation Example 1 using 100 parts of trimethoxysilylbutadiene, 508.4 parts of isopropanol, and 35 parts of 0.01 N hydrochloric acid.

(Preparation Example 6) In Preparation Example 1, methyltrimethoxysilane was used in place of vinylmethoxysilane, and a consumption G for a resin composition was prepared in the same manner. However, 117 parts of isopropanol was used to adjust the amount of the active ingredient.

(Preparation Example 7) Resin composition solution H was prepared in the same manner as in Preparation Example 1, except that phenyltrimethoxysilane was used instead of vinyltrimethoxysilane. However, 138.1 parts of isopropanol was used to adjust the amount of the active ingredient.

Examples 1 to 8 and Comparative Examples 1 to 3 Zinc-rich paint was prepared by mixing zinc powder and extender pigment in the composition shown in Table 1 with the prepared resin composition solution and sufficiently stirring. If necessary, isopropyl alcohol was added to adjust the viscosity, followed by coating, and the following tests were performed.

Coating film adhesion test: Each zinc-rich paint prepared above was 150 × 70 ×
Paint on a 1.6mm sandblasted steel plate by air spraying to a dry film thickness of 15-20μ, expose it outdoors for 7 days after drying, or add 10 minutes in an electric furnace adjusted to 600 ° C.
After heating for one minute, the pressure-sensitive adhesive tape was strongly stuck and peeled off, and the state of peeling of the coating film was examined. As a result, Example 1
In each of the coated steel sheets coated with each of the resin compositions of Nos. To 8, there was almost no peeling of the coating film, but in the case of the coated steel sheet of Comparative Example 4, most of the coating film was peeled.

Topcoat adhesion test: Each zinc rich paint prepared is dried by air spraying on a 150 x 70 x 1.6 mm sandblasted steel sheet to a dry film thickness of 15 to
After the coating was performed so as to have a thickness of 20 μm and the film was exposed outdoors for 7 days after drying, each of the above-mentioned commercially available paints I to III was further coated to a predetermined film thickness and dried indoors for 7 days. Next, a cross cut was made with a cutter knife so as to reach the substrate, the adhesive tape was strongly applied, and the piece was rapidly peeled off, and the state of peeling of the top coat was examined (primary adhesion). Commercial paint I or
For painted II, add 3 to 40 ° C warm salt water.
After soaking for months, the state of peeling of the top coat was similarly examined (secondary adhesion).

 The commercial paints tested are shown below.

Commercial paint I: chlorinated rubber primer (Heinbilt R Primer NA manufactured by Nippon Paint Co., Ltd.) Commercial paint II: Epoxy primer (Nippe Epoxy Primer manufactured by Nippon Paint Co., Ltd.) Commercial paint III: inorganic zinc-rich paint ( As a result, each of the coated steel sheets of Examples 1 to 8 had good primary adhesion and secondary adhesion, and almost no peeling of the top coat, but Comparative Examples 2 and 3 The coated steel sheet is poor in primary adhesion to paints I and III on the market, and poor in secondary adhesion to paints I and II on the market. .

Examples 9 to 12 and Comparative Examples 4 and 5 The sub-powder, extender pigment and additives were mixed with the prepared resin composition solutions according to the formulation shown in Table 2, and the mixture was sufficiently stirred to obtain a zinc-rich paint. Prepared. If necessary, isopropyl alcohol was added to adjust the viscosity, followed by coating, and the following tests were performed.

Thickness test: The zinc rich paint prepared was painted on a 150 x 70 x 1.8 mm steel plate by air spraying to a dry film thickness of 150μ, left indoors for 7 days, and then magnified with a 30x loupe. The presence or absence of cracks in the coating film was observed. As a result, Examples 9 to 12
No crack was found in the coating film of Comparative Example 4, but cracks were found in the coating film of Comparative Example 4.

Topcoat adhesion test: The prepared zinc-rich paint was applied to a 150 x 70 x 1.6 mm sandplast steel plate by air spraying to a dry film thickness of 75μ. After drying, the film was exposed outdoors for 7 days and then marketed as follows. Each of the paints I or II was applied to a predetermined thickness and dried in a room for 7 days. Next, a cross cut was made with a cutter knife so as to reach the substrate, and the adhesive tape was strongly adhered to the base material, and then rapidly peeled off, and the state of peeling of the top coat was examined (primary adhesion). Then, after immersion in warm salt water at 40 ° C. for 3 months, the state of peeling of the top coat was similarly examined (secondary adhesion).

 The commercial paints tested are shown below.

Commercial paint I: Chloride rubber primer (Nine Paint R primer NA, Nippon Paint Co., Ltd.) Commercial paint II: Epoxy primer (Nippe Epoxy Primer, Nippon Paint Co., Ltd.) As a result, each of Examples 9 to 12 was used. The primary adhesion and the secondary adhesion were good for the coated steel sheet, and the top coat was hardly peeled off. However, the coated steel sheet of Comparative Example 5 was poor in primary adhesion to the commercial paint I, and The secondary adhesion was poor for both commercial paints I and II, and most of the topcoat film was peeled off.

As described above, a zinc-rich paint to which the resin composition of the present invention prepared from a trialkoxysilane compound having an unsaturated hydrocarbon group and a tetraalkoxysilane compound is applied has excellent film-forming properties and heat resistance, Unlike the case where a conventional alkyl trialkoxysilane compound is used, the overcoating property is also good.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification symbol FI C09D 183/07 C09D 183/07 (58) Investigated field (Int. Cl. ⁶ , DB name) C09D 183 / 02,183 / 07 C08G 77 / 02,77 / 20 C08K 5/54

Claims (1)

(57) [Claims] (A) a general formula: [In the formula, each R ¹ represents an alkyl group having 1 to 5 carbon atoms which may be the same or different. 100 parts by weight of a mixture of an alkyl silicate and / or a condensate thereof represented by the following formula: and (B) a general formula: [Wherein, R ¹ has the same meaning as described above, and R ² represents a hydrocarbon group having 2 to 5 carbon atoms and having an unsaturated bond. ] A zinc-rich paint resin composition obtained by simultaneously or separately hydrolyzing 5 to 300 parts by weight of a trialkoxysilane compound represented by the formula (C) using an acid catalyst.