KR850000894B1 - Composition of aqueous paints - Google Patents

Abstract

Aqueous anti-rusting paint composition is prepared from emulsion resin(A), pigment(B), film forming agent(C), and water(D). Weight ratio of each component is 40 - 7 : 15 - 40 : 1 - 5 : 5 - 20. (A) is prepared from perfluoro alkyl methacrylate of which chemical formula is CH2=CRCOOCH2(CF2)ICFmHn and mono ethylene unsaturated monomer containing alkyl methacrylate, vinyl or vinylidene group by means of copolymerization in the presence of polymerizing emulsifier such as metal salt of unsaturated aromatic sulfate or polyethylene glycol mono- methacrylate; where R = H or methyl gp.; I = 1 - 8; m = 1 - 3; and n = 3 - m.

Description

Room temperature dry type anticorrosive coating composition

The present invention relates to a composition of a room temperature dry aqueous rust-preventive coating that effectively protects a metal by giving excellent water resistance, rust resistance and adhesion by coating a metal, especially an iron structure.

In the conventional paints, in most cases, the organic solvent occupies a considerable proportion of the constituents of the paint, and as a diluent, an organic solvent should be used. Therefore, the risk of fire during storage or use, environmental pollution caused by painting and drying, Since hygiene has been a problem, in this respect, research and development on so-called non-porous paints such as powder paint, water based paint, high solid paint, and 100% liquid paint such as photocuring are progressing, and are reaching the commercialization stage. Among them, the water-based paints are all extensions of the conventional technology and can be used as existing equipments and have no danger of fire. Therefore, they are spotlighted as air-free paints. Water-based paints and electrodeposition paints are used in some small forms, and there are almost no water-based rust-preventive paints used for bridges, ships, and steel structures. The main reason is that when water-based paints are coated on metals, especially pearl structures, rust is generated due to corrosion reactions in which metals form oxides and hydroxides by contact with water and oxygen, and the most important requirements for solvent-based paints. It was because phosphorus water resistance and rust prevention property fell.

In order to eliminate these problems and reach the required quality level, researches are being conducted in various countries. As the water-based rust-preventing paint compositions developed in foreign countries, there are Japanese Patent Publication Nos. 56-74159, 56-86970, 56-122874, etc. . In this case 56-74159, bitumen emulsion was added to impart water resistance and low air permeability to acrylic emulsion. In case of 56-86970, vinyl acetate-based aqueous emulsion and metal powder with polyvinyl alcohol as protective colloid were coated. The attached pigments were used. In 56-122874, rust preventive pigments were added to latex of vinylidene chloride vinyl chloride copolymer. However, in general acrylic emulsion or vinyl acetate emulsion, the resin itself has poor water resistance, air permeability is high, and latex of vinyl chloride vinyl chloride acryl chloride copolymer has low water and air permeability but poor weather resistance. As water-soluble polymers such as polyvinyl alcohol are used as the low molecular surfactant and dispersion stabilizer, a considerable amount is contained in the paint and remains in the dry coating, resulting in insufficient water resistance and rust resistance when exposed to corrosive environment for a long time.

In the present invention, the polymer emulsifier is used to copolymerize with other monomers to be present in the polymer backbone, thereby increasing the water resistance by not leaving the free emulsifier in the dry coating film after formation of the coating film, and using the polymer containing fluorine. Increased devotion. This is because fluorine-containing polymers have higher thermal motion than hydrocarbon polymers and are easy to slip between molecular chains, so they are flexible at low temperatures, have high bonding strength between carbon and fluorine, and fluorine atoms fill the vicinity of carbon-to-carbon bonds, thereby increasing weather resistance and increasing the surface energy of the polymer. Is very low, so it is difficult to be wetted by other materials, resulting in good chemical resistance and solvent resistance. By using an anti-rust pigment together, the composition of the invention of this invention which has a high film | membrane performance with high rust prevention property, intensity | strength, thermal stability, leveling property, etc. was obtained. The composition of the present invention is obtained by copolymerizing a monoethylenically unsaturated monomer using a polymerizable emulsion and containing one or more alkyl (meth) acrylates or vinyl or vinylidene groups in a perfluoroalkyl (meth) acrylate. It consists of 40-75 weight part of emulsion resins, 15-40 weight part of pigments, 1-5 weight part of additives, such as a coating film formation aid, and 5-20 weight part of water.

Here, the emulsion resin is 0.5-3.0 parts of an anionic unsaturated aromatic sulfonic acid metal salt in an atmospheric pressure or a pressurized half container in an amount of a pH adjusting agent and a reactive emulsifier, and a polyethylene glycol mono (meth) acrylate (ethylene addition mole number 4-20) 0.8-. 220-380 parts of monoethylenically unsaturated monomer containing 18 parts and 0.6-2.5 parts of an initiator and 0.4-2.0 parts of a reducing agent if necessary and heating up to contain one or more alkyl (meth) acrylates or vinyl or vinylidene groups; The monomer mixture consisting of 3-40 parts of perfluoro alkyl (meth) acrylate and 2-10 parts of ethylenically unsaturated acid having general formula CH ₂ = CRCOOCH ₂ (CF ₂ ) 1CFmHn is added dropwise to adjust the pH with alkali after polymerization. One resin. In the above general formula, R is hydrogen or a methyl group and 1-1-8, m = 1-3, n = 3-m.

Examples and comparative examples of the composition of the present invention are as follows.

EXAMPLE

(1) 250 parts by weight of ion-exchanged water, 70 parts by weight of 0.1 mol potassium phosphate, 55 parts by weight of 0.1 N concentration sodium hydroxide, sodium styrene sulfonate in a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube. Parts by weight, 8.5 parts by weight of polyethylene glycol monomethacrylate (additional moles of ethylene oxide 7-9) and 1.3 parts by weight of potassium persulfate were added in a nitrogen atmosphere, and 165 parts by weight of methyl methacrylate at 75 ° C., 2-ethylhexyl acryl 10% of a monomer mixture consisting of 132 parts by weight of rate, 11 parts by weight of pentadeca fluoro octyl acrylate, and 6.2 parts by weight of acrylic acid was added thereto, and the remaining monomer mixture was added dropwise over 3 hours, and heated to react for 1 hour at 82 ° C. After increasing the yield, the mixture was cooled to 30 ° C. and 28% ammonia water was added to obtain a resin having a pH of 8.5, a viscosity of 310 centipoise, and a solid of 45.8%. Joe was.

(2) a. Composition by weight of premix

Water 9.0

BYK-H 36 0.2

Natrazol 250MR 0.2

BYKUMEN WS 1.0

N. Composition parts by weight of pigment mixture

Zinc Phosphate 5.0

Magnesium Silicate 10.0

Strontium Chromate 3.0

Red Iron Oxide 2.6

C. Composition of additional additives

Emulsion resin of the above (1) 66.5

Butyl Cellosolve 1.5

Ethylene Glycol 1.0

The premix was stirred to dissolve well, the pigment mixture was added, dispersed in a high speed dissol ratio, and then additional additives were added with gentle stirring to adjust the pH with high ammonia water to prepare an aqueous coating.

Comparative Example 1 An example of the composition of Japanese Patent No.-122874

The paint was prepared as follows using Haloflex 202 (latex composition of haloflex 202 vinylidene chloride copolymer) manufactured by ICI, UK.

A. Composition parts by weight of latex mixture

Haloflex 202 59.2

Bevaloid 642 (Defoamer) 0.1

Synperonic P 39/70 (30% solution) 2.4

(Synoperonix PE 39/70: Surfactant)

Butyl Cellosolve 2.0

N. Composition of Pigment Dispersion

Synperonic P 39/70 (30 percent solution) 19.6

Fine grinding bar light 456.0

(MICRONISED BARYTES)

Vevaroid 642 2.8

Metocel J. 12 MS

(Methocel J 12MS: thickener) 5.6

Titanium Oxide RAL-2 67.2

Water 300.0

Zinc phosphate jet 40

(Zinc phosphate PZ 40) 160.0

An aqueous coating was prepared by mixing 36.2 parts by weight of the pigment dispersion dispersed with a high speed dissolver and 63.7 parts by weight of the latex mixture using a low speed stirrer.

[Comparative Example 2] An example of an acrylic emulsion paint composition for general rust prevention

The paint was prepared using an acrylic emulsion "Rhoplex MV-9" from Rohm and Hass company as follows.

A. Composition parts by weight of pigment dispersion

Water 3.9

Titanium Oxide RAL-2 (RCR-2) 17.2

Tamol 731 (dispersion) 1.5

Mica (325 mesh water ground mica) 2.1

Triton C F Ten

(Triton CJ-10: Wetting Agent) 0.2

Precipitated potassium carbonate

Precipitated calcium carbonat 10.3

Novco en xget

(Nopco NXZ: Defoamer 0.2

Zinc oxide 0.5

Oncor M-50 6.6

2% Natrosol 250mR

(Natrosol 250MR: thickener) 6.7

Strontium chromate

(Strontium chromate) 0.4

N. Composition of additional additives

Rhoplex MV-9 48.1

Texanol 1.1

Skane M-8 0.2

28% ammonia water 0.2

Nopco NXZ 0.2

13% Sodium Nightlight 0.6

To the pigment dispersion dispersed in a high speed dissolver (additional additive) was mixed using a low speed stirrer to prepare an aqueous coating.

Test results of the general paint properties of the compositions according to the Examples and Comparative Examples prepared as described above were as follows.

In addition, the compositions of the Examples and Comparative Examples were coated on a cold rolled thin plate to have a dry coating thickness of 50 microns, and then the dryness, weather resistance, and mechanical properties of the test results were compared with those of the sandblasted mild steel plate. After coating 50 micron thickness twice (1 day coating interval), and then dried at room temperature for 1 week, the test results of water resistance and rust resistance were as follows.

(색차 : Total Color Difference)는 색차기(Colorimeter XL20)를 사용하여 산출.

(Color Difference: Total Color Difference) is calculated using the Colorimeter XL20.

값을 측정한 결과, 비교예 2의 조성물을 도장한 시험편은 2.5이었고, 비교예 1의 조성물을 도장한 시험편은 3.1로 심하게 변색된 반면, 실시에 조성물을 도장한 시험편은 1.0으로 거의 퇴색, 변색 등이 나타나지 않았다.The compositions of Examples and Comparative Examples were coated on a sanded tungsten plate and a galvanized plate to have a dry film thickness of 40 microns, and then dried at room temperature for one week. After comparing the mechanical properties, the impact resistances were comparable. In the case of excellent adhesion to the horseshoe plate, but only coated the galvanized plate with the example composition, the weather resistance test by artificial ultraviolet irradiation after 240 hours

As a result of measuring the value, the test piece coated with the composition of Comparative Example 2 was 2.5, and the test piece coated with the composition of Comparative Example 1 was severely discolored to 3.1, whereas the test piece coated with the composition in Example was almost faded and discolored to 1.0. The back did not appear.

Claims (1)

Perfluoroalkyl (meth) using a metal salt of unsaturated aromatic sulfonic acid and polyethylene glycol mono (meth) acrylate (ethylene oxide addition mole number 4-20) as a polymerizable emulsifier and having the general formula CH ₂ = CRCOOCH ₂ (CF ₂ ) I CFmHn. ) 40-75 parts by weight of an emulsion resin in which an acrylate is copolymerized with one or more alkyl (meth) acrylates or a monoethylenically unsaturated monomer containing a vinyl group or a vinylidene group, followed by pH adjustment with alkali. A room temperature dry type aqueous rust-preventive coating composition comprising 40 parts by weight, 1-5 parts by weight of an additive such as a film forming aid and 5-20 parts by weight of water. In the above general formula, R is hydrogen or a methyl group, I = 1-8, m = 1-3, n = 3-m.