JPS5813665A - Aqueous primer for metal - Google Patents

Abstract

PURPOSE:The titled primer, containing a chlorine-containing resin, resin stabilizer and a metallic surface treating agent in a specific proportion, capable of inhibiting the dehydrochlorinating reaction, and having improved etching effects, and forming stable films. CONSTITUTION:A primer containing (A) 100pts.wt. of a chlorine-containing resin which is a copolymer obtained from (i) vinylidene chloride, (ii) vinyl chloride, (iii) an alkyl acrylate and/or alkyl methacrylate, and/or (iv) an alpha,beta-unsaturated carboxylic acid, (B) 0.5-10pts.wt. resin stabilizer, e.g. a basic lead compound, and (C) 0.1-5pts.wt. metallic surface treating agent, e.g. phosphoric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-based primer for metals that forms stable coatings.

Efforts are being made to make the currently widely used solvent-based paints water-based due to the risks of flammability, F8 emissions, and environmental hygiene, and the use of water-based paints is also being considered in the field of anticorrosive paints. .

Chlorine-containing resins such as polyvinyl vinylide, polyvinylidene chloride, their copolymers with other monomers, chlorinated polyolefins such as chlorinated polyethylene, chlorinated polypropylene, and chlorinated rubber are known for their chemical resistance, weather resistance and It has excellent water resistance, and when used as a paint vehicle, it dries quickly and has good workability, so it is widely used for concrete and topcoating. However, when an emulsion of a chlorine-containing resin is applied to a metal surface such as a steel material, the dehydrochloric acid reaction causes the underlying surface to rust, so this emulsion-type paint cannot be applied directly to a blasted or rusted surface. Therefore, this emulsion type paint is usually applied after the sandblasted steel has been primed with a zinc-rich paint or an etching primer as a shop primer. Also,
When a chlorine-containing resin emulsion is used as a paint, the acid generated in the dehydrochlorination reaction tends to react with the metal container during storage, and gas is likely to be generated, so there are also concerns about storage stability.

The present invention was proposed in order to improve the above-mentioned problems regarding chlorine-containing resins that have excellent properties as paints. Therefore, the object of the present invention is to form a stable coating film for metals by adding a resin stabilizer and a metal surface treatment agent to a chlorine-containing resin emulsion to suppress the dehydrochloric acid reaction and have a beading effect. To provide a water-based primer.

Examples of chlorine-containing resins used in the present invention include homopolymers and copolymers of vinyl chloride and vinylidene chloride, copolymers of these with other monomers, and chlorinated polymers such as chlorinated polyethylene and chlorinated polypropylene. ;Olefins,
There are many such as chlorinated rubber.

Preferred examples include vinyl chloride, vinylidene chloride,
(c) Co-electrochemical combinations of alkyl acrylates (or methacrylates) and/or α-1β-unsaturated carboxylic acids are included. Methods for producing emulsions of these chlorine-containing resins are known per se, such as the above-mentioned method. Suitable copolymers include Lautul sulfate as a surfactant for emulsion polymerization, ammonium persulfate as an initiator, and sodium pyrosulfite as an activator.
By copolymerizing at an autoclave width of about 60:'C, 22% vinyl chloride, 70% vinylidene chloride, 2-
6% ethylhexyl acrylate and 2% acrylic acid
to be produced as a copolymer emulsion containing
′ can be done.

Examples of effective resin stabilizers include basic lead compounds, organotin compounds, and base resin compounds; basic lead compounds include tribasic lead sulfate, basic lead silicate, or dibasic lead phthalate; The organic tin compound is a dibutyltin compound such as dibutyltin dilaurate, dibutyltin maleate or dibutyltin distearate, and the organic resin compound is a glycidyl ether type epoxy resin (for example, Epon 828 manufactured by Shell Chemical Co., Ltd.) or an epoxidized ester resin. (For example, ADEKASIZER 0130F manufactured by Asahi Denka Co., Ltd.) is an example. These resin stabilizers are used alone or in combination of two or more in the primer according to the present invention.

The amount of resin stabilizer added is 10% of the chlorine-containing resin emulsion.
It is preferably 1.0 to 10 parts by weight relative to 0 parts by weight, particularly preferably 0.5 to 5 parts by weight for organic resin stabilizers, and less than 0.5 parts by weight for organic resin stabilizers. If it is, the stabilizing effect will be low, while if it exceeds 0.5 parts by weight, the coating will remain sticky, which is not preferable.

In order to test the stabilizing effect of the resin stabilizer used in the present invention, the resin stabilizer was added to a chlorine-containing resin emulsion, and after stirring with a disper, a polished steel plate (#240 polishing) was prepared.
19/drrl and examine the occurrence of subcontracting after 24 hours. In Table 1, ○ indicates no subcontracting.
and those with subcontracting are indicated by X, and for comparison, the case where no resin stabilizer is added is also investigated. All units are parts by weight.

(Left below) Examples of metal surface treatment agents include phosphoric acid and boric acid. Phosphoric acid is preferred, but boric acid is also effective.
It is preferable that the amount is 0.1 to 5 parts by weight based on the overlapping part, and within this weight range, the primer according to the present invention can be adjusted to be weakly acidic. Generally, the metal surface treatment agent is added at the final stage of primer production, thereby adjusting the primer of the present invention to be slightly acidic, preferably at a pH of 3-6. If the pH of this paint is less than 3.0, storage stability remains a problem, while if the pH exceeds 6.0, it is undesirable because it tends to cause flash last when directly applied to steel materials.

The primer according to the present invention can be used as an undercoat paint having a film thickness of 30 to 100 μm by adding additives such as extender pigments, antirust pigments, and coloring pigments. In this case, rust-preventing pigments include lead phosphate, barium metaborate, silica phosphate, zinc molybdate, etc., coloring pigments include Bengara, titanium, carbon black, etc., and other additives include Thickeners, antifoaming agents, surfactants, preservatives, antifungal agents, etc. Paint pH immediately after production with various additives added
Since there are many different types of p
Although H is adjusted, if the pH of the paint itself is basic, the film forming reaction with phosphoric acid or boric acid becomes extremely slow. Therefore, it is particularly important to surround the paint itself with a slightly acidic atmosphere; film formation is promoted in this atmosphere, resulting in a dense and uniform paint film.

In order to produce a paint according to the present invention, resin stabilizers, extender pigments, anti-rust pigments, antifoaming agents, deionized water, etc. are mixed, and these are pre-mixed using known production equipment such as a colloid mill or a side mill. Make a pigment paste by dispersing until Next, a chlorine-containing resin emulsion is added to the pigment paste while stirring, and finally a metal surface treatment agent of phosphoric acid or boric acid is added to adjust the pH to 3 to 6.

In the primer according to the present invention, the chlorine-containing resin emulsion contains a predetermined amount of a resin stabilizer and a metal surface treatment agent. Conventionally, lead compounds, organic tin compounds, metal soaps, epoxy compounds, and antioxidants have been used for chlorine-containing resin-based solvent-based paints.

Although resin stabilizers such as ultraviolet absorbers have been used, it was unclear which resin stabilizers are effective and how effective they are for emulsion-type paints.

Furthermore, because conventional emulsion-type paints are quite alkaline, it is not possible to add phosphoric acid, boric acid, or acidic pigments as metal surface treating agents. In contrast, in the present invention, the dehydrochlorination reaction is suppressed by adding a specified resin stabilizer to the chlorine-containing resin emulsion, which improves storage stability and prevents rusting of the base material even when applied directly to steel materials. Forms a stable coating film without any scratches.

Furthermore, by simultaneously adding phosphoric acid or boric acid as a metal surface treatment agent, the acidity is adjusted to be weakly acidic, so it exhibits an etching effect as iron phosphate or iron borate on sandblasted steel surfaces, and is completely protective. This is made possible by actively stabilizing rust in the form of crystals such as iron phosphate in contrast to the two types of corrosion that do not rust.

Next, Examples of the present invention are shown in Table 2. At this time, a sample containing no resin blinding agent and metal surface treatment agent is also shown as a comparative example. All units are parts by weight.

(The following is a blank space) Table 3 shows the properties of the paints in the above examples. The paint was applied with a brush at a coating weight of 19/dm' for one day, and then subjected to a tsuruto spray for 500 hours. In Table 3, good results are indicated by ○, poor results are indicated by X, and the middle is indicated by Δ.

(Leaving space below) Procedures Amendment August 1, 1985 1゜ Commissioner of the Japan Patent Office 1, Indication of the case Patent No. 112595 of 1982 2.2, Title of the invention Water-based primer for metals 3
“3. Person making the amendment 4゜Relationship with the case Patent applicant name Nippon Paint Co., Ltd. 5゜4, Agent 5, Date of notice of reasons for refusal Showa 1999, Month, Day Voluntary 6. Inventions D & None increased by amendment i, Target of amendment: Contents of the amendment The word "emuldiene" on page 2, lines 18-19 of the specification is corrected to "emulsion."

"0.5 parts by weight" on page 5, line 16 is corrected to "5 parts by weight."

"Additive" on page 8, line 15 is corrected to "pigment component."

On page 8, line 17, "lead phosphate" is corrected to "zinc phosphate."

"Side mill" on page 9, line 12 is corrected to "sand mill."

Table 3 on page 14 of the same page is corrected as shown in the attached sheet.

Claims (4)

[Claims] (1) A product for metals containing as main components 0.5 to 10 parts by weight of a resin stabilizer and 0.1 to 5 parts by weight of a metal surface treatment agent per 100 parts by weight of a salt-containing resin emulsion. Water-based primer. (2) The chlorine-containing resin is (a) vinylidene chloride, (b)
vinyl chloride, ()) alkyl acrylate and/or alkyl methacrylate, and/or to) α. The primer according to claim 1, which is a copolymer derived from β-unsaturated carboxylic acid. (3) The primer according to claim 1, wherein the resin stabilizer is a basic lead compound, an organic tin compound, or an organic resin compound, and is used alone or in a mixture of two or more kinds in the primer. (4) The primer according to claim 1, wherein the metal surface treatment agent is phosphoric acid or boric acid, and the primer is adjusted to be weakly acidic.