JPS6233262B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to corrosion-resistant and waterproof compositions for structures made of metal, such as iron, which are susceptible to corrosion. Conventionally, corrosion-resistant compositions for iron structures have been prepared by mixing color vehicles such as red lead, red iron oxide, iron oxide, zinc yellow, chrome red, lead powder, and zinc powder with boiled linseed oil, stand oil, and varnish. There are paints, and a method is used to prevent corrosion by applying such paints once or twice to iron structures. If necessary, paints containing pigments in phenolic resin, epoxy resin, polyurethane, alkyd resin, vinyl chloride resin, or synthetic rubber can be applied.
A method of applying two top coats is used. Conventional anti-corrosion paints have little flexibility; for example, when painted on a steel tank, they resist expansion and deformation of the steel material due to stress applied to the tank wall, or when painted on a bridge steel frame, they resist deflection and vibration of the beam. On the other hand, the paint film cannot follow large displacements such as where beams are assembled or riveted together, or joints such as iron roofs, and small cracks and cracks may occur. The problem was that rainwater and airborne pollutants, ie, acidic substances such as sulfur dioxide gas and nitrogen oxide gas, entered from this area, accelerating corrosion. In addition, the thinner the paint film, the faster the weather resistance will deteriorate, the paint film itself will become hard and brittle due to sunlight, causing cracks, and the ability to follow the deformation of the structure as described above will be poorer. Become. With conventional paints such as those mentioned above, 50μ is applied in one coat.
It is difficult to apply a thicker coating, and even if it were possible to apply a thick coating, there would be problems such as dry cracking and sagging of the coating, and therefore it would be necessary to apply it several times. The drawback was that it did not. In addition, since the film is thin, for example, in the case of the above-mentioned structure, not all surfaces are coated, pinholes are formed here and there, and corrosion occurs from there. Such conventional anti-corrosion paints have a service life of about two years in normal environments, and must be repainted after about three years at most, and corrosion begins in about six months in adverse environments such as factories or near the coast. There is a drawback. The present inventors have completed the present invention as a result of various studies aimed at improving the drawbacks of the prior art. That is, the present invention provides an emulsion of an acrylic resin in which 60% by weight or more of the constituent monomers is an acrylic acid alkyl ester having an alkyl group having 2 to 10 carbon atoms, and an evaporation residue based on 100 parts by weight of the acrylic resin. The present invention relates to a corrosion-resistant and waterproof composition for metal structures comprising a bituminous emulsion in an amount of 10 to 300 parts by weight. Here, the reason for using an acrylic resin emulsion containing a specific amount of a specific acrylic acid alkyl ester as a constituent monomer is that the resin itself has excellent weather resistance;
In addition, since a soft resin with a low glass transition point is obtained, abnormalities such as cracking will not occur even if thick coating is applied at one time. In addition to being excellent in weather resistance, the resulting coating film has the ability to follow substrate cracks, is flexible even at low temperatures, and is resistant to movement of structures and substrate cracks even in winter, and is resistant to substrate cracks at high temperatures. This is to prevent sag and decrease in strength. Furthermore, by blending the bituminous emulsion, the cohesive force and density of the bituminous emulsion make the paint film water resistant, and prevent airborne pollutants that enter with rainwater, such as acidic sulfur dioxide gas and nitrogen oxide gas. Blocks substances from penetrating and increases gas permeation resistance.
It protects underlying metal structures by blocking water vapor and pollutant gases in the air. Thus, the anti-corrosion composition of the present invention has excellent properties such as thick coating properties, weather resistance, substrate crack followability (at low temperatures and high temperatures), water permeability, and gas permeability.
By having a semi-permanent barrier function from the outside world, it completely eliminates contact between the metal surface and oxygen and water, which causes rust, and protects the underlying metal structure from corrosion. In the present invention, the acrylic acid alkyl ester having an alkyl group having 2 to 10 carbon atoms as a constituent monomer of the acrylic resin emulsion includes ethyl, n-propyl, iso-propyl, n-butyl, and iso-acrylic acid. -butyl, sec-butyl, n
-amyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-
There are esters such as decyl. As monomers constituting the acrylic resin in the present invention, various monomers commonly used in the production of acrylic resins, other than the above-mentioned acrylic acid alkyl esters, may be used in combination. These monomers include acrylic acid or methacrylic acid, as well as ethylene, vinyl acetate, vinyl chloride, vinylidene chloride,
Acrylonitrile, styrene, butadiene, acrylic acid alkyl esters other than the above-mentioned acrylic acid alkyl esters, itaconic acid, maleic acid, clodonic acid, and the like are preferably used. For the above acrylic resin emulsion, an acrylic acid alkyl ester having an alkyl group having 2 to 10 carbon atoms is used because it maintains flexibility at low temperatures and does not cause cracking even when coated thickly. An acrylic acid alkyl ester having an alkyl group having 4 to 10 carbon atoms is used. The content of acrylic acid alkyl ester as a constituent monomer of the acrylic resin emulsion in the present invention is 60 to 100% by weight, preferably 90% by weight.
~99.5% by weight. As other constituents other than acrylic acid alkyl ester, acrylic acid or methacrylic acid is particularly preferred, but of course the other monomers mentioned above may also be used arbitrarily. The blending amount of acrylic acid, methacrylic acid or other monomers is 40% by weight or less, preferably
It is 0.5-10% by weight. If the amount of acrylic acid alkyl ester as a constituent monomer of the acrylic resin emulsion used in the present invention is less than 60% by weight, the weather resistance of the resin itself will decrease. Furthermore, if the amount of acrylic acid, methacrylic acid, or other monomer is less than 0.5% by weight, the toughness of the coating film decreases and cracks tend to occur in the coating film. On the other hand, if the amount of acrylic acid, methacrylic acid or other monomers is too large, the flexibility of the coating film will decrease,
The structure's ability to follow cracks decreases, and its corrosion protection performance decreases. The solid content concentration of acrylic resin emulsion is usually 30 to 70% by weight, and there are three types depending on the type of emulsifier: cationic, anionic, and nonionic.
You can get different types. Next, the bituminous substances constituting the bituminous emulsion used in the present invention include, for example, asphalts such as straight asphalt, blown asphalt, semi-blown asphalt, propane-deasphalt, lake asphalt (natural asphalt), coal tar, and oil gas. Tars such as tar, pitches such as tar pitch, tall oil pitch, fatty acid pitch, mineral oil, heavy mineral oil, etc.
A bituminous material made of seeds or a mixture of two or more kinds, and a bituminous material having an evaporation residue penetration degree (25° C.) of about 40 to 200, is preferably used. In the present invention, the bituminous material is generally mixed in water with an evaporation residue of 40 to 80% by weight using a suitable emulsifier or, if necessary, an emulsification aid or stabilizer.
It is dispersed to a certain degree and used as a bituminous emulsion. The amount of the bituminous emulsion added is the evaporation residue of the bituminous emulsion per 100 parts by weight of the resin content of the emulsion of the resin containing the alkyl acrylic ester.
The amount is 10 to 300 parts by weight, preferably 30 to 200 parts by weight. If it is less than 10 parts by weight, the effect of improving the water permeability and gas permeability of the film will be reduced. If the amount exceeds 300 parts by weight, the coating film will sag or become significantly soft at high temperatures of around 80°C, resulting in problems during the daytime in midsummer. The evaporation residue of the bituminous emulsion in the present invention is
It was determined according to JIS K 2208 petroleum asphalt emulsion, and specifically, 200g of sample was placed in a metal evaporator.
Accurately weigh out the sample, heat it on an electric heater or gas burner while stirring, and after it is confirmed that the water in the sample has disappeared, heat it at 160°C for 1 minute to remove the evaporation residue after heating (g ) and weigh the sample.
Calculate as a percentage of (g). It is of course possible to add aggregates, surfactants, viscosity stabilizers, antifoaming agents, etc. to the corrosion-proofing and waterproofing composition of the present invention, if necessary. Examples of aggregates include talc, mica, acid clay, diatomaceous earth, kaolin, quartz, iron powder, fly ash, satin white, titanium oxide, ferrite, lithopone, baryta, asbestos, wood flour, pulp powder, zirconia, and carbon black. , white carbon, and various cements such as Portland cement, blast furnace cement, and alumina cement.The amount of these added is preferably 5 to 5 parts by weight per 100 parts by weight of the resin content of the acrylic resin emulsion. The amount is 1000 parts by weight, more preferably 20 to 200 parts by weight. The surfactants used when making bituminous emulsions and the surfactants used when mixing aggregates include the following. In the case of cationic surfactants, cationic surfactants such as alkylamine salt type, monoalkyl quaternary ammonium chloride salt type, dialkyl quaternary ammonium chloride salt type, polyoxyethylene alkylamine type, and imidazoline salt type are used. In the case of nonionic type, glycerin, propylene glycol fatty acid ester type, sorbitan fatty acid ester type, polyoxyethylene sorbitan fatty acid ester type, polyoxyethylene fatty alcohol ether type, polyoxyethylene alkyl phenyl ether type, oxyethylene oxypropylene block polymer type Nonionic surfactants such as are used. In the case of anionic soaps, anionic surfactants such as resin soaps, fatty acid soaps, higher alcohol sulfate ester types, alkylbenzene sulfonate types, naphthalene sulfonic acid formalin condensate types, polyoxyethylene sulfate salt types, etc. agent is used. It is preferable to blend such a surfactant in an amount of about 0.05 to 5 parts by weight per 100 parts by weight of the resin content of the acrylic resin emulsion. In this case, the toughness of the coating film tends to decrease. Furthermore, a nonionic surfactant and a cationic or anionic surfactant may be used in combination. Examples of viscosity stabilizers used include soda, potash, and ammonium salts such as ligninsulfonic acid, polyacrylic acid, polymethacrylic acid, and tripolyphosphoric acid. It is preferably about 0.1 to 5 parts by weight. In addition, antifoaming agents include octyl alcohol, caprylic alcohol, lauryl alcohol, and cyclohexanol, and the blending amount is 100 parts by weight of the resin content of the acrylic resin emulsion.
It is preferably about 0.005 to 0.2 parts by weight. The corrosion-proofing and waterproofing composition of the present invention is applied or sprayed onto the surface of a metal structure to be corrosion-proofed and waterproofed to form a coating film. No. 2, 20°C), particularly preferably about 500 to 5000 cps. If the viscosity is less than 300 cps, the leveling property will be too high and it will be difficult to coat thickly at once.Also, if the viscosity is high, it will be possible to coat thickly, but if the viscosity is too high, there will be difficulties in coating. There is a tendency. In the present invention, the above composition has extremely good adhesion to the surface of a metal structure, and the coating film is highly flexible and has excellent weather resistance. In the present invention, the composition is applied to the surface of a metal structure by a known method such as spraying, roller, or brush, to form a thick film of 50μ or more in one application, and the structure is It completely follows displacement, etc., allows for sufficient filling and coating even in the gaps of structures, and causes very little deterioration of the coating film, thus dramatically increasing the corrosion-preventing effect. If the thickness of the formed film is too thin, the ability to follow cracks in the base material will be reduced, resulting in pinholes and corrosion of the underlying metal frame. Although cracks will be eliminated, if the film is too thick, there will be no corresponding improvement in the effect, so the film thickness should be 50μ or more, preferably 100μ.
μ or more, particularly preferably 300 to 5000 μ. Further, in the present invention, a conventional anticorrosive paint may be applied to the surface of the structure in advance, or a conventional paint suitable for the design purpose may be applied as a top coat of the paint of the present invention. In addition, the objects to be subjected to corrosion protection in the present invention are mainly tanks made of iron, such as cast iron and steel, which are easily corroded.
It may be a metal structure such as a bridge or a roof, or it may be a pretreated metal structure such as a galvanized iron plate, a chromium-treated steel plate, a colored galvanized iron plate, etc. Next, details of the present invention will be explained using examples. All parts and percentages in the examples are by weight.
It is. Further, the tests in Examples are as follows. 1. Preparation of test specimen A corrosion-proofing and waterproofing composition was applied by air spray to one side of an SS-41 iron plate (150 x 70 x 3 mm), and a top coat was further applied as necessary. 20℃, 60
After curing for 10 days under %RH conditions, various tests were conducted. 2 Corrosion Prevention Performance Test After various deterioration treatments of the above test specimens, the film appearance of the anticorrosive composition, adhesion to the underlying SS41 steel plate, and the presence or absence of rust on the underlying steel plate under the coating were examined. Film appearance: The presence or absence of abnormalities in film appearance changes (blisters, peeling, cracks, etc.) after various deterioration treatments was visually observed. Adhesion test: Based on the adhesion strength test of JIS A 6909 (synthetic resin emulsion sand wall spray material)
A 40 x 40 mm square steel attachment was glued to the untreated and variously degraded paint films, and the adhesion strength of the paint film was measured using a Kenken type adhesive strength tester. Occurrence of rust: After the above adhesion test, the paint film was removed using a cutter or the like, and the surface of the underlying SS41 iron plate was visually observed to see if rust had occurred. Next, various deterioration treatments will be described. 3 Various deterioration treatments Water resistance: The test specimen prepared in 1 was placed under water.
Impregnated for 168Hr. Salt water spray test: 2% saline solution was sprayed for 1000 hours while maintaining the ambient temperature at 35±2°C using a Toyo Rika Kogyo model ST-J salt water spray tester. Weather resistance: JIS A in accordance with JIS A 6910
Ultraviolet treatment using 1415 was performed for 1000 hours. still,
Water was sprayed onto the test specimen at a rate of 6 minutes/1 hour. The bituminous emulsions used in the Examples and Comparative Examples are as follows. 1 Cationic asphalt agent (hereinafter simply referred to as C-1) Straight asphalt (penetration 150-200)
can be emulsified using an emulsifying liquid containing alkyl (curing fat) trimethylammonium chloride as the main emulsifier, and its properties are shown in Table 1. 2 Nonionic asphalt emulsion (hereinafter simply referred to as N-1
) Straight asphalt (penetration 150-200)
was obtained by emulsifying it using an emulsifier containing polyoxyethylene nonylphenol ether (HLB≒14) as the main emulsifier, and its performance is shown below.
Shown in 1. 3 Anionic asphalt emulsion (hereinafter simply A-
1) Straight asphalt (penetration 150-200)
It was obtained by emulsifying the following using an emulsion containing sodium alkylbenzenesulfonate as the main emulsion, and its properties are shown in Table 1. Here, the penetration of straight asphalt is
Measured in accordance with JIS K 2530, petroleum asphalt penetration test. Furthermore, the properties of bituminous emulsion are JIS
Measured according to K 2208 petroleum asphalt emulsion.

[Table] Example 1 A composition consisting of 90 parts of butyl acrylate, 5 parts of ethyl acrylate, 1 part of methacrylic acid, 4 parts of styrene, 1 part of sodium alkylbenzenesulfonate as an emulsifier, 0.3 parts of ammonium persulfate, and 100 parts of water was prepared. 75
Polymerization was carried out by a conventional polymerization method at a temperature of 5 hours at a temperature of 0.degree. C. to produce a polymer emulsion with a solid content of 48%, and the pH was adjusted to 7.0 by adding aqueous ammonia. Kao Atlas
Add 1 part of Emulgen 910 manufactured by Co., Ltd., 30 parts of Karion clay as aggregate, 10 parts of calcium carbonate, 1.0 part of polyacrylic acid as a viscosity stabilizer, and 0.3 part of caprylic alcohol as an antifoaming agent, and mix well. A corrosion-resistant and waterproof composition was obtained. The above corrosion-resistant and waterproof composition was applied to the film thickness using an airless spray gun in accordance with the above test method.
A 1.0 mm sample was prepared. Furthermore, on the next day, an acrylic lacquer-based Aron coat Topcoat FC color manufactured by Toagosei Kagaku Co., Ltd. was applied at a coating amount of 0.3 kg/m ² using air spray. After leaving this for 10 days at 20°C and 60% RH, the performance was measured according to the above test method. The results are shown in Table 2. No abnormality was observed in the appearance of the paint film even after various deterioration treatments.
It has sufficient adhesion to the base iron plate, and
No rust was observed on the SS41 iron plate, which was in good condition. Examples 2 to 5 According to the procedure of Example 1, an acrylic resin emulsion was prepared using the monomers shown in Table 2, and a bituminous emulsion etc. was added as shown in Table 2 to produce a corrosion-resistant and waterproof composition. , the results of the same test are shown in Table 2.
As shown in the figure, all were good. Comparative Examples 1 to 4 According to the procedure of Example 1, as shown in Table 3, the corrosion-resistant and waterproof composition was coated with only a resin emulsion mainly composed of acrylic acid alkyl ester as a binder, and an acrylic lacquer-based FC color was added as a top coat. (Comparative Example 1), when only a bituminous emulsion was used as a binder (Comparative Example 2), when a resin with a low content of acrylic acid alkyl ester was used (Comparative Example 3), when a large amount of bituminous emulsion was used. Corrosion-proofing and waterproofing compositions were prepared for those coated with acrylic Lutzkartupcoat and FC Color (Comparative Example 4), and the performance was examined in the same manner. Due to peeling, cracking, and poor water vapor permeability of the coating film itself, rust occurred on the underlying SS-41 steel plate, and it was defective.

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Claims (1)

[Claims] 1 60% by weight or more of the constituent monomers have 2 or more carbon atoms
An emulsion of an acrylic resin, which is an acrylic acid alkyl ester having 10 alkyl groups, and an evaporation residue of 10 to 300 parts per 100 parts by weight of the acrylic resin.
A corrosion-protecting and waterproofing composition for metal structures, comprising parts by weight of a bituminous emulsion.