JPH0446932A - Resin composition for zinc-rich paint - Google Patents

Abstract

PURPOSE:To improve film-forming properties, etc., while maintaining heat resistance, etc., by hydrolyzing a specific alkyl silicate (condensate mixture) and a trialkoxysilane compd. simultaneously or separately in the presence of an acid catalyst. CONSTITUTION:100pts.wt. alkyl silicate (condensate mixture) of formula I (wherein R<1> is a 1-5C alkyl) (e.g. tetraethoxysilane) and 5-300pts.wt. trialkoxysilane compd. of formula II (wherein R<2> is an unsatd. 2-5C hydrocarbon group) (e.g. vinyltrimethoxysilane) are hydrolyzed simultaneously or separately in the presence of an acid catalyst (e.g. hydrochloric acid) to give the objective compsn., which is used as a binder to be compounded with a rust-proof pigment comprising zinc oxide having a mean particle diameter of 1-20mum, thereby giving an inorg. zinc-rich paint.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resin composition for inorganic zinc-rich paint.

[Prior art] Zinc-rich paints containing zinc dust as a rust-preventing pigment are generally divided into organic zinc-rich paints that use epoxy resins and the like as binders, and inorganic zinc-rich paints that use alkyl silicate hydrolysis condensation resins. be. Inorganic zinc rich paint has low drying properties and m
Due to its excellent heat resistance, durability, and anti-corrosion performance, it is used as a primer for systems such as primary rust prevention paint using thin film coating or long-term corrosion protection using thick film coating for ships, bridges, tanks, plants, and marine structures. Widely used for large steel structures such as

When inorganic zinc-rich paint is used in a thin film as a primary rust-preventing paint, the amount of zinc powder added must be reduced due to hygiene issues due to the generation of zinc fume during welding and cutting, and problems with topcoat selectivity such as the inability to overcoat with alkyd paints. is desired. However, when zinc dust is reduced, the coating film becomes hard and brittle due to the characteristics of silicate resin, resulting in poor adhesion to the substrate, especially in areas heated to high temperatures such as the back side of welding and the back side of strain relief. On the other hand, when used in a thick film anticorrosion paint, the more zinc powder is added and the film thickness is increased, the more advantageous it is to long-term corrosion protection. However, when the film thickness is increased, cracks tend to occur due to the characteristics of the silicate resin, making it difficult to form a coating. As described above, inorganic zinc-rich paints using an alkyl silicate hydrolyzed synthetic resin as a binder have a limited ability to form a coating film.

Conventionally, in order to compensate for the above drawbacks, Japanese Patent Application Laid-Open No. 49-1634
Although it has been proposed to mix in organic components as disclosed in the above publications, it has not been possible! There are drawbacks such as heat resistance that detract from the advantages. In addition, as disclosed in Japanese Patent Application Laid-open No. 59-64671 and Japanese Patent Publication No. 63-28942,
It has been proposed to use trifunctional alkyltrialfukidisilane compounds as part of the binder resin. Although these can improve film-forming properties without sacrificing the advantages of inorganic zinc-rich paints such as heat resistance, the alkyl groups directly bonded to silicon reduce the surface tension of the paint film, so Adhesion becomes poor.

[Problems to be Solved by the Invention] The purpose of the present invention is to improve film-forming properties while retaining the advantages of inorganic zinc-rich paints such as I and I thermal properties, and to provide a top coat without reducing the surface tension of the coating film. An object of the present invention is to provide a resin composition with good adhesion. Another object of the present invention is to provide an inorganic zinc-rich paint with excellent performance prepared from the resin composition.

[Means for Solving the Problems] As a result of intensive research into trialkoxysilane compounds, the present inventors have specified the binder resin composition using trialkoxysilane compounds having a certain structure. The present invention was completed based on the discovery that the surface tension of the coating film does not decrease and the overcoatability is not adversely affected.

That is, the present invention provides the following formula:
represents an alkyl group. 1 100 mm parts of an alkyl silicate and/or a condensed forest mixture thereof represented by: represent ] 5 to 3 fl of a trialfukidisilane compound represented by
A resin composition for zinc-rich paint obtained by simultaneously or separately hydrolyzing the nffJt portion using an acid catalyst (C) is provided.

In the present invention, each alkyl ZrR' constituting the alkoxy group of component (Δ) and component (1'3) blended as a binder raw material is the same or different alkyl group having 1 to 5 carbon atoms, and cannot be hydrolyzed. It turns into alcohol and disperses from the paint film. Therefore, the number of carbon atoms is 6
If it is more than that, the drying of the coating film becomes slow, which is not preferable. (A)
Regarding the components, specific examples of the alkyl silane include tetramethoxysilane, tetraethoxysilane, tetra-n-propoquine, and tetra-n-butoxysilane. In addition, the initial hydrolysis condensate refers to a mixture of polyalfoxydisilane oligomers obtained by hydrolyzing some alkoxy groups of these tetramethquine silanes, for example, ethyl silicate 40.
(manufactured by Fullcoat Co., Ltd.) and Methyl Silicate) 51 (manufactured by Colcoat Co., Ltd.). The hydrolyzed condensation of these (Δ) components is known as a binder resin for inorganic zinc-rich paints, but when using it alone as a binder as mentioned above, the amount of zinc powder added must be adjusted. If it is reduced or coated in a thick film, it has the disadvantage that it cannot provide a good coating film. Therefore, in the present invention, component (B) is further blended as a binder raw material.

The hydrocarbon group Rt directly bonded to silicon of component (B) is
It is a hydrocarbon group having 2 to 5 carbon atoms and containing an unsaturated bond, and specific examples include alkenyl groups such as vinyl, allyl, propenyl, and butadienyl, and alkynyl groups such as propargyl. These unsaturated hydrocarbon groups having 6 or more carbon atoms tend to lower the surface tension of the coating film and impair the heat resistance of the coating film, which is not preferable. In addition, especially when the zinc-rich paint to which this resin composition is applied is used as a primary rust-preventing paint, the paint film will not be burnt out and will be good even in areas that are heated to high temperatures, such as the back side of welding or the back side of strain relief. Since it is necessary to exhibit membrane performance, it is preferable that the number of carbon atoms is smaller, and specifically, vinyl groups and allyl groups are preferable.

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

The resin composition in the present invention is obtained by blending components (A) and (B) in advance and then subjecting them to hydrolytic condensation under acidic conditions using an acid catalyst (C). Also,
Component (A) and component (B) are separately treated as an acid catalyst (C).
The mixture may be mixed after being hydrolyzed under acidic conditions. The acid catalyst (C) may be one commonly used, such as inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid,
Examples include organic acids such as formic acid, propionic acid, and citric acid.
These may be used alone or in combination of two or more.

The blending amount of component (Δ) and component (B) is 5 to 30% of component (Δ) + 00ffifft part of component (B).
It is preferable to mix 0 ITI parts by weight, more preferably 10 to 200 parts by weight. If the blend m of the component (r3) is too small, the film-forming properties of the zinc-rich paint using the present resin composition tend to deteriorate. On the other hand, if it is in excess, the drying properties of the zinc-rich paint will be poor and the anticorrosion properties will also tend to decrease. The formulation m may be adjusted as appropriate depending on whether the zinc-rich paint using the present resin composition is applied as a secondary anticorrosion paint or a thick film type long-term anticorrosion system.

In order to form a zinc-rich paint from the resin composition of the present invention, commonly used pigment solvents, additives, etc. may be appropriately blended as necessary. The zinc powder may be a normal one, that is, one with an average particle size of 1 to 20μ and any shape, such as spherical or flake, and in an amount that can exhibit coating film performance, for example, over a long period of time. When applied to heavy corrosion protection systems, the weight ratio of the total solid content of the coating is 50 to 9.
About 5% by weight may be used. In addition, when used as a secondary rust-preventing paint, as mentioned above, a large amount of zinc fume is generated, which poses a sanitary problem. is preferable. As pigments other than zinc dust, it is possible to use substance type #1 used in Noyujo's anti-rust paints, anti-rust pigments, coloring pigments, etc. Specifically, talc, mica, barium sulfate, clay, carbonic acid, etc. Runum, zinc white, titanium white,
Examples include red iron phosphate, zinc phosphate, aluminum phosphate, barium metaborate, aluminum molybdate, iron phosphide, and the like. Solvent components include ethanol, n-propertool, impropertool, n-butanol, isobutanol, ethyl heptarosol, butyl cellosolve, methyl ethyl ketone (MEK), methyl isobutyl ketone (
(MIBK), toluene, xylene, etc., and may be blended in an appropriate amount so as to obtain appropriate coating workability and coating film drying properties. Additives include commonly used anti-sagging agents,
A lubricant, a reaction accelerator, a color separation inhibitor, etc. may be added in appropriate amounts depending on the purpose.

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

[Effects of the Invention] The present invention is characterized in that the binder resin composition of a zinc-rich paint is specified using a trialkoxysilane compound having an unsaturated hydrocarbon group such as component (B). When a resin composition using a trialkoxysilane compound having such an unsaturated hydrocarbon group is applied as a binder for a zinc-rich paint, or when a resin composition using a known alkyltrialkoxysilane compound is applied. Similarly, the present invention has excellent film-forming properties and heat resistance, but the effects of the present invention are not limited to these. The present invention provides excellent adhesion without reducing the surface tension of the coating film.

The present invention will be specifically explained below with reference to Examples.

Unless otherwise specified, parts are based on ffff1.

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

(FJyJ Preparation Example 1) 100 parts of tetraethoxysilane and 20 parts of vinyltrimethoxysilane were dissolved in 3 parts of isopropanol 122°,
After 21 parts of 0.01N hydrochloric acid was added dropwise, the mixture was heated and stirred at 60° C. for 3 hours to complete the hydrolysis reaction, thereby preparing a resin composition solution A.

(Preparation Example 2) 100 parts of tetraethoxysilane was added to Impropatool 75
Dissolved in 0.0 parts. Resin composition solution B was prepared in the same manner as in Preparation Example 1 by adding 17 parts of O1 normal hydrochloric acid dropwise. Separately, add 100 parts of vinyltrimethoxysilane to Improper Tool 2.
Resin composition solution C was prepared in the same manner by dissolving 33.4 parts of the resin composition, and adding 18 parts of 0, O1 normal hydrochloric acid dropwise.
and were mixed in the proportions shown in Tables 1 and 2.

(Preparation Example 3) 100 parts of ethyl silica) 40 (manufactured by Colcourt), 200 parts of allyltriethoxysilane, Improper Tool 5
24.1 part, 0. Preparation Example 1 using 50 parts of O1 normal hydrochloric acid
A resin composition solution was prepared in the same manner as (Preparation Example 4) Using 100 parts of tetrabutoxysilane, 40 parts of allyl-1-noethoxysilane, 90 parts of imbronokol, and 16.5 parts of 0.01N hydrochloric acid. Resin composition solution E was prepared in the same manner as in Preparation Example 1.

(Preparation Example 5) 100 parts of methyl silicate 51 (manufactured by Colcoat) 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 0.01N hydrochloric acid.

(Preparation Example 6) Resin composition solution G was prepared in the same manner as in Preparation Example 1, except that methyltritoxysilane was substituted for vinyltrimethoxysilane (1). However, in order to combine the active ingredients m, isopropanol was Part was used.

(Preparation Example 7) i In Preparation Example 1, phenyltrimethoxysilane was used instead of vinyltrimethoxysilane.1. A resin composition solution H was prepared by adjusting the X to the same tM. However, in order to match the amount of active ingredients, 138.1 parts of Inpropatool was used.

Examples 1 to 8 and Comparative Examples 1 to 3 Zinc dust and extender pigments were mixed with the prepared resin composition solution according to the formulation shown in Table 1, and thoroughly stirred to prepare zinc-rich paints. After adjusting the viscosity by adding isopropyl alcohol as necessary, it was coated and the following tests were conducted.

Paint film adhesion test: Each zinc rich paint prepared above was
A sandblasted steel plate of X1.611jl was coated with air spray to a dry film thickness of 15 to 20μ, and after drying, it was exposed outdoors for 7 days, or it was further coated for 10 minutes in an electric furnace adjusted to 600°C. After heating for a minute, adhesive tape was strongly applied and rapidly peeled off to examine the peeling state of the coating film. As a result, the coated steel plates coated with each of the resin compositions of Examples 1 to 8 had almost no peeling of the coating, but the coated steel plate of Comparative Example 4 had most of the coating peeled off.

Topcoat adhesion test: Each prepared zinc rich paint was tested at 150X70XI,
611 sandblasted steel plate with air spray to a dry film thickness of 15 to 20 μm, and after drying and exposing it outdoors for 7 days, apply each of the above commercially available paints ■ to ■ to a predetermined film thickness of 4 μm. It was further painted and dried indoors for 7 days. Next, use a utility knife to make a cross cut to reach the base material, firmly apply the adhesive tape and peel it off quickly.
The peeling state of the top coat film was examined (-secondary adhesion). Commercially available paint! Or, for those painted with ■, further increase the temperature to 40°C.
After immersion in warm salt water for 3 months, the peeling state of the top coat was examined in the same manner (secondary adhesion).

The commercially available paints tested are shown below.

Commercially available paint 1: Chlorinated rubber-based brimer (Nippon Paint Co., Ltd. Hi-Bilt R Brimer NA) Commercially available paint ■: Eboxy-based brimer (Nippe Paint Co., Ltd.! 2 Nippe Eboxy Brimer) Commercially available paint ■: Inorganic zinc rich paint (Nippa Jinki-1000QC manufactured by Nippon Paint <n>) As a result, each coated steel sheet of Examples 1 to 8 had good primary adhesion and secondary adhesion, and there was almost no peeling of the top coat, but Comparative Example 2 The coated steel plates of Nos. and 3 were poor in secondary adhesion to commercially available paints I and ■, and poor in secondary adhesion to both commercially available paints I and H.
Most of the top coat peeled off.

Examples 9 to 12 and Comparative Example 4.5 Zinc powder, extender pigment, and additives were mixed into each of the prepared resin composition solutions according to the formulation shown in Table 2, and thoroughly stirred to form a zinc rich paint of 812 mm. did.

After adjusting the viscosity by adding isopropyl alcohol as necessary, it was coated and the following tests were conducted.

Thick film property test: The prepared zinc rich paint was tested at 150X70XQ, 8
Dry film thickness is 150 by air spraying on zm sanded steel board.
The coating was coated so as to have a coating film of μ, and after being stored indoors for 7 days, the presence or absence of cracks in the coating film was observed using a 30x louver. the result,
Although no cracks were observed in the coating films of Examples 9 to 12,
Cracks were observed in the coating film of Comparative Example 4.

Topcoat adhesion test: The prepared zinc rich paint was 150X70X161
A 1H sandblasted steel plate was coated with air spray to a dry film thickness of 75 μm, and after drying, it was exposed outdoors for 70 times, and then each of the following commercially available paints 1 or 2 was applied to the specified film thickness. It was dried indoors for a day. Next, use a cutter knife to make cross cuts to reach the base material.
A sticky tape was strongly applied and rapidly peeled off to examine the peeling state of the top coat (-sub-adhesiveness). Next, soak in warm water at 40°C for 3 months. nL, the peeling state of the top coat was examined in the same manner (secondary adhesion).

The commercially available paints tested are shown below.

Commercially available coating $-11: Chlorinated rubber primer (Hi-Bilt R Brimer NA manufactured by Nippon Paint Co., Ltd.) Commercially available paint ■: Epoxy-based brusher (Nippe Epoxy Brimer manufactured by Nippon Paint Co., Ltd.) As a result, Examples 9 to 12 The painted steel sheets of Comparative Example 5 had good primary adhesion and secondary adhesion, and there was almost no peeling of the top coat, but the painted steel sheet of Comparative Example 5 had poor secondary adhesion compared to commercially available paint L. In addition, secondary adhesion was poor for both commercially available paints 1 and 2, with most of the top coat peeling off.

As mentioned above, the zinc-cured sochi paint to which the resin composition of the present invention prepared from the trialfukidisilane compound and the tetraalkoxysilane compound having an unsaturated hydrocarbon group has good film-forming properties and heat resistance, Unlike the case where conventional alkyltrialkoxysilane compounds are used, the overcoatability is also good.

Claims (1)

[Claims] (1) (A) General formula, ▲ Numerical formula, chemical formula, table, etc. ▼ [I] [In the formula, each R^1 is a carbon number of 1 to 1 which may be the same or different.
5 represents an alkyl group. ] 100 parts by weight of an alkyl silicate and/or a condensate mixture thereof, and (B) General formula, ▲ Numerical formula, chemical formula, table, etc. ▼ [II] [In the formula, R^1 has the same meaning as above, R ^2 represents a hydrocarbon group having 2 to 5 carbon atoms and having an unsaturated bond. ] A resin composition for zinc-rich paint obtained by simultaneously or separately hydrolyzing 5 to 300 parts by weight of a trialkoxysilane compound represented by (C) using an acid catalyst.