JPS6050227B2 - Rust and corrosion protection coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rust- and anti-corrosion coating composition for steel materials.

More specifically, by coating the steel surface with a polymer cement mortar composition consisting of a vinyl chloride synthetic resin emulsion and quick-hardening cement, the steel material can have rust-proofing, anti-corrosion properties,
An object of the present invention is to provide a rust-preventing and anti-corrosion coating composition for the purpose of imparting decorative properties. Conventionally, various methods have been proposed to prevent rust and corrosion of steel materials, of which the use of anti-rust paints is the most common.

Rust-preventive paint is a paint that consists of a rust-preventive pigment such as a lead-based compound or zinc powder and a vehicle, and because it is solvent-based, it poses problems in terms of fire safety, resource conservation, and human safety. There is. In addition, the rust prevention effect differs significantly depending on the degree of surface preparation of the steel material, and generally a complete treatment of Class 1 staining is required, so the time and cost of surface preparation takes up the entire painting work. The proportion of surface damage is large, and surface preparation is a big problem, especially when repainting or repairing. In addition, anti-rust paints have poor weather resistance and chemical resistance, and the film thickness is O, 3.
It is generally thin with a thickness below Tfgn, and there is a problem with durability when used in an environment with severe wear resistance. On the other hand, there are various methods of preventing rust and corrosion other than anti-rust paints, such as coating steel pipes for gas, water, and seawater transmission with cement mortar using ordinary Bolland cement.

Since this method is water-curable, it is non-polluting and does not require the use of solvents like anti-corrosion paints.Moreover, the strong alkaline atmosphere of cement passesivates the surface of the steel material and exerts a rust-preventing effect. There is no need for complete surface preparation,
Another feature is that even if some moisture adheres to the surface of the steel material, it can be coated. However, cement mortar has inherent drawbacks such as the occurrence of cracks as the cement hardens and shrinks, and poor properties such as mechanical strength, impact resistance, abrasion resistance, and acid resistance. Currently, it is hardly used for purposes other than cement lining of steel pipes and cast iron pipes, and even with cement lining of steel pipes, due to the above-mentioned drawbacks, the coating thickness has to be reduced to 5.
~207TL17T1. Because it is thicker, it is heavier, and its poor impact resistance and adhesion properties cause problems such as cracking and peeling during transportation or installation. Although cement mortars other than alumina cement have a remarkable rust-preventing effect on steel materials, they are not generally put to practical use as anti-rust coating materials because of the inferior properties of cement mortars as described above.

In addition, ordinary Voltland cement takes a long setting time of 2 hours or more and a curing period of 2 days or more before it develops strength.
In painting work, there are problems such as dripping and running, and when applying multiple coats, the interval between coats becomes long. Polymer cement mortar is known as a method for modifying various properties of cement mortar.

Synthetic resin emulsions such as polyvinyl acetate, polyacrylic acid ester, styrene, butadiene copolymer, vinyl chloride, vinylidene chloride copolymer, etc. are used as admixtures, and this is mixed with cement mortar to improve various properties of cement mortar. This is the way to do it. Depending on the type and amount of synthetic resin emulsion added, such polymer cement mortar has various properties such as shrinkage rate upon curing, water resistance, chemical resistance, abrasion resistance,
Impact resistance, mechanical properties, adhesion, etc. are often improved. Examples of objects to be coated with the rust-preventing and anti-corrosion coating composition of the present invention include the interior and exterior walls of tanks, chemical plants, bridges, and steel towers, which are generally highly corrosive and require so-called heavy anti-corrosion coating. Steel materials such as roofs and interior and exterior walls of buildings that are coated with anti-corrosion paint! In order to cover a wide range of objects and maintain durability, adhesion to steel materials is of paramount importance.

Steel material expands and contracts due to cold and heat, and steel coverings must have sufficient adhesion and flexibility to keep up with the repeated expansion and contraction of the steel material.Also, thin steel materials have a certain degree of curvature. The resulting coating is also required to have sufficient adhesion and flexibility to prevent cracking, peeling, etc. from occurring due to repeated bending.

Other properties required for coatings on steel materials include impact resistance, abrasion resistance, chemical resistance, and water resistance. Steel exterior wall coverings are often exposed to wind and rain, so it is desirable that their water absorption rate be low, and the occurrence of efflorescence, which is characteristic of cement, impairs the appearance. It is also essential that the steel coating has good weather resistance.

When considering polymer cement mortar as a rust-preventing and anti-corrosion coating composition for steel materials, conventional ones have various drawbacks.

For example, JP-A No. 50-44221 discloses a cement mortar composition for steel pipe lining, but it is a rust prevention method for a limited target of steel pipes, and because it has poor weather resistance, it is used as a rust prevention method for general copper materials. It is not suitable as an anticorrosion material, and Japanese Patent Publication No. 47-38527 discloses a synthetic resin emulsion for mixing with cement whose main component is vinyl chloride, but the polymer cement mortar used here is not suitable for use under harsh conditions. It is not suitable for use as a rust-preventing and anti-corrosion coating composition on steel materials without any consideration being given to adhesion to steel materials or painting workability.

The present inventors have already invented a rust-preventive and anti-corrosion coating composition in Japanese Patent Application No. 52-43778 in consideration of these various required performances, but the present invention provides a rust-preventive and anti-corrosion coating composition with an improved lateral layer. A composition is provided.

That is, Japanese Patent Application No. 52-43778 discloses (a) 35 to 65% by weight of vinyl chloride monomer, and (b) 15 to 62% by weight of an acrylic acid alkyl ester or methacrylic acid alkyl ester (excluding methyl methacrylate) monomer. Heel weight% (c) Vinyl acetate monomer 2-15% by weight (d) Monoethylenically unsaturated carboxylic acid or its anhydride monomer 0.1-5
obtained by emulsion polymerization of a monomer mixture consisting of % by weight,
A synthetic resin emulsion with a polymer glass transition temperature of 30°C or less is mixed with a fast-setting cement at a polymer/cement ratio (
p/c) (weight ratio of polymer to cement) is 0.
The synthetic resin emulsion is mixed in a range of 2 to 0.6, and aggregates, surfactants, pigments, and other additives are added as necessary to obtain a rust-preventing and anti-corrosion coating composition for steel materials. The monoethylenically unsaturated carboxylic acid or its anhydride, which is a polymer component, contributes to improving the mechanical stability, chemical stability, and storage stability of synthetic resin emulsions. It also has the effect of delaying the hardening of hard cement, and has the problem of not being able to take full advantage of the performance of fast-hardening cement, which hardens very quickly.
This is a problem when coating steel with polymer cement mortar, when increasing the coating thickness in one coat, when coating at low temperatures, preventing dripping, or shortening the time during which multiple coats can be applied. . In addition, the presence of monoethylenically unsaturated carboxylic acids or their anhydrides increases curing shrinkage of fast-setting cement, resulting in 1T
If the coating thickness is 0n or more, cracks will occur on the surface of the polymer cement mortar due to curing shrinkage. Rust will occur from this area, so the coating thickness in one coat will be limited, and if the coating thickness is to be increased, the number of coatings will be increased. There is a need to. Additionally, monoethylenically unsaturated carboxylic acids or their anhydrides degrade the water or alkali resistance of polymers compared to when they are not present, and when mixed with fast-setting cement, they may be exposed to a very strong alkaline atmosphere. This is not desirable when considering the appearance and durability of polymer cement mortar coverings over a very long period of time. The same applies when the polymer cement mortar coating is placed in a hot and humid environment. The inventors of the present invention have made extensive studies to solve the problems of the conventional method, and as a result, have arrived at the present invention.

That is, the present invention (a) 30 to 7% vinyl chloride monomer,
(b) a monomer mixture consisting of 15 to 68% by weight of alkyl ester of α/β unsaturated carboxylic acid (excluding methyl methacrylate) monomer, and (c) 2 to 15% by weight of vinyl acetate monomer. A synthetic resin emulsion of which the glass transition temperature (Tg) of the polymer obtained by emulsion polymerization in the essential presence of a polyvinyl alcohol derivative having a sulfonic acid group is 30°C or less is combined with a fast-setting cement and a polymer/cement ratio (p/c). ) (weight ratio of polymer to cement) is in the range of 0.2 to 0.6, and aggregate, surfactant, pigment, and other additives are added as necessary to prevent rust and corrosion of steel. The present invention relates to coating compositions. To explain the present invention in more detail, problems such as slow curing of fast-setting cement, large curing shrinkage of fast-setting cement, or poor water resistance and alkali resistance of polymers can be solved by the polymer component of the synthetic resin emulsion. This is a problem caused by a certain monoethylenically unsaturated carboxylic acid or its acid anhydride, and the mechanical stability, chemical stability, and storage stability of synthetic resin emulsions can be improved without using the monoethylenically unsaturated carboxylic acid or its acid anhydride. We have discovered that it is appropriate to carry out emulsion polymerization in the presence of a polyvinyl alcohol derivative having a sulfonic acid group in order to have sufficient stability and not cause any adverse effects as a rust- and corrosion-proofing coating composition. be. The synthetic resin emulsion of the present invention has sufficient mechanical stability and chemical stability so that it will not coagulate even when subjected to strong mechanical pre-shearing when mixed with fast-setting cement or by polyvalent cations contained in cement. It also has good storage stability and excellent cement miscibility.

In addition, since the synthetic resin emulsion hardly impairs the hardening speed of fast-setting cement, when coating steel materials with the composition of the present invention, it is possible to increase the coating thickness in one coat or when coating at low temperatures. There is no sagging or running, and the strength of the polymer cement mortar is quick, so the interval between multiple coats of paint can be shortened. In addition, the curing shrinkage of polymer cement mortar has been improved, so even if the coating thickness is increased in one coat, no cracks will occur on the surface during the curing process, making it possible to reduce the number of coats, making it extremely easy to manage the coating process. becomes. As for the coating film performance, the synthetic resin emulsion has a polymer/cement ratio (p/c
) is within the range of 0.2 to 0.6, the adhesion with copper material is significantly strong, and the surface temperature of the steel material is 5 to 10.
Adhesion is good even when coated at low temperatures of °C, and the coated steel does not peel or blister due to repeated heating and cooling, impact, repeated bending, immersion in seawater or water, etc., and has sufficient adhesion even under harsh conditions. Compared to the composition of Japanese Patent Application No. 52-43778, it has stronger mechanical strength and is superior in water resistance, alkali resistance, etc.

Furthermore, the coating composition obtained by the present invention can provide good adhesion and anti-rust/corrosion effects even when the surface preparation of steel materials is relatively incomplete. It is particularly effective, and because it can easily and inexpensively obtain a larger coating thickness than existing paints, it has the characteristic of being sufficiently durable even in environments where there is severe abrasion due to flying sand and the like.

It also has the advantage of being non-polluting since it does not require the use of any solvent. The synthetic resin emulsion used in the present invention includes (a) 30 to 7% vinyl chloride monomer;
(b) Alkyl ester of α/β monounsaturated carboxylic acid (
However, excluding methyl methacrylate) Monomers 15 to 68
(C) The glass transition temperature (Tg ) is a synthetic resin emulsion with a temperature of 30°C or less. In such a synthetic resin emulsion, copolymer particles having a particle size of about 0.05 to 2.0 microns are dispersed in water, and the solid content is preferably 30% or more. When the solid content is 30% or less, in the case of a composition with a large polymer/cement ratio, the amount of water is too large, making it difficult to adjust the fluidity of the composition. Vinyl chloride monomer is 30-70% by weight
If it is more than 7%, the polymer will become hard and the film forming property will be poor, and the adhesion between the polymer cement mortar as a rust-preventing and anti-corrosion coating will be poor, and the flexibility will be impaired, resulting in poor flexibility and impact resistance. . In addition, if the water content is less than 3%, the water resistance of polymer cement mortar, especially water absorption and efflorescence, will be poor, and as a rust- and corrosion-preventing coating, it will have problems in terms of durability and appearance, and chemical resistance, especially alkali. It is not suitable as it becomes weak against. Alkyl of α●β monounsaturated carboxylic acid. Examples of esters (excluding methyl methacrylate) include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, etc. with a carbon number of 1 to 1. In particular, acrylic acid alkyl esters having 4 to 12 alkyl groups; 1 to 1 carbon atoms such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc. 1 hat, especially 4
~! Methacrylic acid alkyl esters having 12 alkyl groups; dimethyl maleate, diethyl maleate, dibutyl maleate, dioctyl maleate, dilauryl maleate, etc., which have 4 to 12 alkyl groups in a cap of 1 to 1 carbon atoms, etc. Dialkyl maleate having 1 to 1 carbon atoms, especially 4 to 12 alkyl groups such as dimethyl fumarate, diethyl fumarate, dibutyl fumarate, dioctyl fumarate, dilauryl fumarate, etc. Examples include dialkyl itaconate having an alkyl group of 1 to 1 carbon atoms, particularly 4 to 12 carbon atoms, such as diethyl itaconate, dibutyl itaconate, dihexyl itaconate, dioctyl itaconate, and dilauryl itaconate. This component imparts flexibility to the polymer through its internal plasticizing effect, thereby increasing the film-forming properties and bonding strength of the cement mortar.

It also contributes to adhesion to steel materials. α in polymer
・Content of alkyl ester of β-monounsaturated carbononic acid (excluding methyl methacrylate) is 15-6% by weight
It is desirable to maintain the glass transition temperature (Tg) of the polymer at 30°C or less. If it is less than 15% by weight, the polymer becomes hard, poor film-forming properties, and the polymer cement mortar becomes difficult to maintain. Flexibility is impaired and adhesion to steel materials is also weakened. Also 6
If the heel weight exceeds %, the amount of vinyl chloride monomer used is relatively reduced, and the polymer cement mortar becomes inferior in water resistance, particularly water absorption and efflorescence, and its mechanical strength also decreases. The vinyl acetate monomer increases the bonding strength with the mortar and contributes to the adhesion between the polymer cement mortar and the copper material, and is preferably 2 to 15% by weight.

If it exceeds 15% by weight, the adhesion is sufficient, but the water resistance of the polymer cement mortar, particularly the water absorption rate, efflorescence, is poor, and the alkali resistance is also poor, causing blistering and peeling of the coating.

If the amount is less than 2% by weight, the adhesion between the polymer cement mortar and the steel material will be poor and peeling will occur at the interface under severe conditions.

The polyvinyl alcohol derivative having a sulfonic acid group in the present invention is used to provide a synthetic resin emulsion with excellent mechanical stability, chemical stability, and storage stability. A polyvinyl alcohol derivative having a sulfonic acid group is a polyvinyl alcohol having one SO3M (M represents a sodium, potassium atom or ammonium ion) in the side chain. Examples of such polyvinyl alcohol derivatives having sulfonic acid groups include those obtained by copolymerizing vinyl acetate with polymerizable α●β-unsaturated sulfonic acids or salts thereof such as vinyl sulfonic acid, allylsulfonic acid, and styrene sulfonic acid. , saponification, neutralization, or alkali neutralization after sulfonation of polyvinyl alcohol. Usually, a polyvinyl alcohol derivative having a sulfonic acid group content of 0.5 to 10 mol % is used. The amount of the polyvinyl alcohol derivative having a sulfonic acid group varies depending on the type and amount of monomers to be polymerized, but it is usually 0.5 to 5% by weight based on the total monomers charged.
In particular, it may be used in an amount of 1 to 4% by weight. Furthermore, in carrying out the present invention, the presence of a nonionic surfactant in the polymerization system improves the mechanical stability, chemical stability, storage stability, and dispersibility of the synthetic resin emulsion when mixed with fast-setting cement. It is more preferable because it improves the results.

Such nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene aliphatic esters, and polyoxyethylene alkyl ethers having a hydrophilic-lipophilic balance (hereinafter referred to as HL.B) of 15 to 18.5. Examples include oxyethylene sorbitan fatty acid ester, polyoxyethylene/polyoxypropylene block copolymer, etc. These can be used alone or in combination.The amount of nonionic surfactant added to the polymerization system is 0 based on the total monomers charged. Generally used in the range of .5 to 5% by weight. As the water-soluble catalyst used in carrying out the present invention, all catalysts used in the polymerization of vinyl chloride can be used.

In addition, it is possible to add specific inorganic salts to eliminate the formation of coarse particles (approximately 2μ or more) during polymerization of synthetic resin emulsions and to produce synthetic resin emulsions with excellent mechanical stability and storage stability. .

The specific inorganic salt is at least one inorganic salt selected from alkali metal or ammonium sulfates, hydrochlorides, and phosphates. The amount of inorganic salt added is usually 0.1 to 1. Selected within the range of call volume %. In addition to these monomers, radical copolymerizable monomers such as α-olefin, fatty acid vinyl ester, aromatic vinyl, acrylonitrile, methacrylonitrile, and halogenated vinyl monomers other than vinyl chloride are used in combination. It is also possible to blend synthetic resin emulsions consisting of the monomers mentioned above.

These are used in an amount of 2% or less based on the total monomers.
Such a synthetic resin emulsion is used by mixing with fast-setting cement at room temperature, so it has good film-forming performance even at room temperature, and it also has enough flexibility to provide a certain degree of flexibility as a coating for steel materials. Therefore, it is desirable that the glass transition temperature (Tg) of the polymer is 30°C or lower.

As for the cement used in the present invention, when coating steel with polymer cement mortar, it is necessary to use a fast-curing cement to prevent dripping or shorten the time required for multiple coats of paint, and a fast-curing cement is suitable for this purpose. It is. What is continuous hardening cement?11Ca0●7A1203●
Cax2 (x is a halogen atom), 3Ca0-SiO2,
It contains CasO4 as an essential component. In the present invention, fast-setting cement is most suitable, but colloidal cement, ultra-fast hardening cement, etc. can also be used if there is no particular need to reduce sagging during painting or shorten the time for recoating the paint, and there are no problems with the painting work. White cement can also be used if it is colored. A polymer/cement ratio of 0.2 to 0.6 is desirable; if it exceeds 0.6, the polymer cement mortar that covers the steel material becomes too flexible, and at high temperatures, the surface becomes sticky, resulting in poor stain resistance, and mechanical The strength is also weakened, which is not appropriate. If it is less than 01, the polymer component is small and the adhesion to the steel material is poor, and the polymer cement mortar becomes too hard, resulting in poor bending resistance and impact resistance. In the present invention, aggregates or fillers are used as necessary.

As for the type of aggregate, any type of aggregate that is normally used in cement mortar can be used, but for workability and to obtain a homogeneous steel coating, it is better to use one with a uniform particle size.
No. 8 silica sand is suitable, and the amount used is preferably 4 or less as a weight ratio of aggregate to cement. Adhesiveness and flexibility are poor, and mechanical properties also deteriorate. Surfactants and dispersants can also be used, including nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene sorbitan monostearate, lignin sulfonate, rosinate, Anionic surfactants such as alkylbenzene sulfonates can be used as dispersants, wetting agents, and water reducing agents for cement, and should preferably be used in an amount of 5% by weight or less based on the cement. slow down the setting time of

Pigments can also be used as coloring agents, and it is appropriate to add them as an aqueous dispersion to the synthetic resin emulsion.
The type and amount of pigment to be added can be determined in a conventional manner. Water-soluble polymers can also be added, which improves the thixotropy of polymer cement mortar and is effective in preventing dripping and flow during painting, and also reduces the elongation of polymer cement mortar when painting with brushes, rollers, etc. It has the effect of improving

Examples of water-soluble polymers that can be used include common ones such as cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, and carboxymethyl cellulose, polyvinyl alcohol, polytin, polyacrylate, and alginate, and the amount added is determined by polymer cement. It is used in an amount of 2% by weight or less per mortar. Also, by adding an antifoaming agent, it is possible to minimize the inclusion of air bubbles during kneading of polymer cement mortar.

As the antifoaming agent, commercially available antifoaming agents that are generally added to synthetic resin emulsions can be used, but silicone antifoaming agents have the greatest antifoaming effect. The amount of antifoaming agent added is 1% by weight or less per polymer cement mortar. Other admixtures usually added to cement, such as carbonate as an accelerating agent, water glass, gypsum as a slowing agent,
Carboxylic acids and the like can also be used depending on the purpose.

It is also possible to use glass fiber, which has good alkali resistance, for reinforcement. Kneading of the composition according to the present invention can be carried out at room temperature using various types of mixers normally used for cement kneading or hand mixers, but since fast-setting cement is used, the fluidity of the composition gradually decreases as the kneading time increases. Therefore, it is not appropriate to mix for a long time, and it is preferable to keep the mixing to less than 2 times.

The coating of this composition on steel materials is done by air spray. Leh,
Spray painting using airless spray etc. is most suitable.
A coating with less air bubbles and a good finished appearance can be obtained.

For areas that cannot be sprayed, methods such as brushing or roller coating are also possible. Depending on the coating method
The optimum flow properties of such compositions are determined. Fluidity can be adjusted by adjusting the particle size of the aggregate or the amount added, but it is generally adjusted by increasing or decreasing the amount of water added. The objects to be coated with the anti-rust and anti-corrosion coating composition obtained by the present invention are not only those in which general anti-rust paints are used, but also other areas such as the inner and outer layers of tanks, heavily corroded chemical plants, steel towers, bridges, ships, etc. It can be used in the field of so-called heavy-duty anti-corrosion coatings.

It can also be used to coat the inner and outer surfaces of water supply, sewage, and water supply steel pipes, and for lining plates used for construction purposes to prevent rust and corrosion, and to prevent slipping. Moreover, on top of the coating composition according to the present invention, a top coat may be applied such as a long-oil-based phthalic acid resin paint, a two-component epoxy that cures at room temperature, a urethane resin, a vinyl chloride solvent-based paint, a chlorinated rubber, or a weather-resistant, It is possible to overcoat a synthetic resin emulsion with good water resistance etc. as a top coat, and by doing so, a coating with better appearance and durability can be obtained.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited only to these Examples.

Example 1 Ion-exchanged water 35e was charged into a high-pressure polymerization vessel with an internal volume of 100' equipped with a stirring device, and then 0.3 part of potassium persulfate, 0.5 part of anhydrous sodium sulfate, HL. Polyvinyl alcohol derivative with saponification degree of 98% containing 2.0 parts of polyoxyethylene nonylphenyl ether of Bl 7.2 and 2 mol% of sodium sulfonate (1) Manufactured by Honsei Kagaku Kogyo Co., Ltd., CKS-50) 2 ．． After charging and sealing, oxygen was removed by nitrogen purging and vacuum, and 44 parts of vinyl chloride monomer, w parts of vinyl acetate, and 4 parts of 2-ethylhexyl acrylate were added.
The copolymer emulsion obtained by adding 1 part of triethanolamine to 6 parts of triethanolamine after polymerizing at 50°C for 12 hours and 70°C for 1 hour had a solid content concentration of 50.4% and a pH of 8. \
The average particle diameter was 0.23μ, and the glass transition temperature of the polymer was 0°C.

Next, 10 parts of quick-hardening cement (Jet Cement 8, manufactured by Sumitomo Cement Co., Ltd.) and 15 parts of No. 8 silica sand were thoroughly kneaded, and 10 parts of the above copolymer emulsion and 1 part of the above copolymer emulsion were added.
1L, Bl3. 1.25 parts by weight of polyoxyethylene octylphenol ether and 7 parts by weight of water are poured and mixed. The flow value of the obtained polymer cement mortar slurry by P load was 508. Next, Table 1 shows the results of various tests using this polymer cement mortar slurry. Example 2 Vinyl chloride monomer 5? A copolymer emulsion obtained by polymerizing 5 parts of vinyl acetate and 43 parts of butyl acrylate in the same manner as in Example 1 was used in a polymer cement mortar slurry mixed with quick-setting cement in the same manner as in Example 1. The results of various tests are shown in Table 1.

Comparative Example 1 Polyvinyl alcohol derivative 2 with saponification degree of 98 mol% containing 2 mol% of sodium sulfonate of Example 1
．． Change to 0 parts and add 2 parts of sodium dodecylbenzenesulfonate.
Table 1 shows the results of various tests when the rainbow part was used.

As can be seen from these results, sodium dodecylbenzenesulfonate also has poor mechanical stability of the copolymer emulsion.
Also, the emulsion solidifies during mixing with fast-setting cement. A polyvinyl alcohol derivative containing 2 mol % of sodium sulfonate and having a degree of saponification of 98 mol % is effective in improving the mechanical stability of the copolymer emulsion and improving the dispersibility of fast-setting cement. Comparative Example 2 Instead of using 44 parts of vinyl chloride, 1 part of vinyl acetate, and 46 parts of 2-ethylhexyl acrylate in Comparative Example 1, 4 parts of vinyl chloride was added. Table 1 shows the results of various tests when w parts of vinyl acetate, 46 parts of 2-ethylhexyl acrylate, and 2 parts of acrylic acid were charged.

As can be seen from this result, the presence of acrylic acid improves the mechanical stability and dispersibility of the fast-setting cement of the copolymer emulsion, but compared to Examples 1 and 2, the water resistance and alkali resistance are slightly lower. If the drying shrinkage rate is large and the film thickness becomes 1wt or more after one coating, cracks will occur on the surface of the coating film. Moreover, the curing time is slow and the time required for recoating is long, resulting in drawbacks such as problems. Comparative Example 3 10 parts of fast hardening cement and 15 parts of No. 8 silica sand were thoroughly kneaded and 94 parts by weight of water was poured into the mixture and mixed.

The flow value of the obtained cement mortar slurry based on p-load was (a) seconds. Table 1 shows the results of various tests using this cement mortar slurry. In the Examples and Comparative Examples of the present invention, each characteristic value and test result was measured by the method shown below.

(1) Polymer glass transition temperature (Tg): Measured using a differential thermal analyzer (DSC) manufactured by PerkinElmer.

(2) Mechanical stability of emulsion: Emulsion 150
3 at 13,000 rpm with a Hamilton Beach mixer.
After stirring, the resulting coagulate was dried separately using a 100-mesh wire gauze and expressed in weight % based on the polymer content.

In addition, when the entire emulsion coagulated and solidified within 3 times, the time until then was shown. (3) Cement dispersibility: Polymer cement mortar slurry 3 using an experimental stirrer
00y was made and stirring was continued for 1 minute at about 1000 r'Pm, and the polymer cement mortar slurry was visually observed for abnormal viscosity increase, generation of coagulation, etc., and those with no abnormalities were evaluated as good.

If any abnormality was found, the condition was indicated. (4)
Flow value by p load: Measured according to the Japanese Society of Civil Engineers standard 64 Prepacked concrete pouring mortar consistency test method (method by p load).

(5) Adhesion: An iron rod with a diameter of 15W0fL is glued to the surface of the polymer cement mortar of the iron plate coating, and a cut is made in the polymer cement mortar layer along the outer periphery of the iron rod, using a 100 kg autograph manufactured by Shimadzu Corporation and a tensile speed of 10.
T! The adhesive strength was measured using THLImln, and the breaking state and strength at the time of breaking were shown.

(6) Flexibility: Using a JISK-5400-1970 mandrel bending tester, cracks that reach the base of the steel plate occur in the polymer cement mortar layer of the steel plate coating when rotated around a mandrel (3Tr0!L diameter). The rotation angle was measured and shown.

(7) Cold-heat cycling test: The iron plate coating is heated at 100°C for 15 minutes and then immediately cooled at -40°C.

This process was repeated 50 times and the adhesion between the polymer cement mortar coating and the iron plate, cracks, and changes in appearance were observed with the naked eye, and those with no abnormalities were rated as good. If any abnormality was observed, the condition was recorded. (8) Impact resistance: J
A load of 112 inches and 1 kg was dropped from a height of 50 cm using a test device of 6.13B of ISK-5400-1970, and the condition of the polymer cement mortar layer on the steel plate coating was observed with the naked eye.If no cracks or peeling were observed, it was evaluated as good. If there is an abnormality, the condition is recorded.

(9) Salt spray test: A cross cut is made according to JIS Z237l, and after 10 (1) hours, visually observe the rusting state, adhesion, appearance change, and spot rust on the cross cut part, and check if there are no major changes. Items were considered to be in good condition, and those with abnormalities were noted.

Accelerated weathering resistance: Using an accelerated weathering tester according to JISK-5400-1970, visually observe changes in the appearance of the iron plate coating after irradiation for 1 hour, rusting state, blistering, and peeling. Those with no change were considered good, and those with abnormalities were noted. (11) Effloretscens The iron plate coating was exposed outdoors for 6 months and the occurrence of effloretscens was observed with the naked eye.

(12) Water resistance, chemical resistance: After immersing the iron plate coating in each reagent listed in Table 1 for 3 months, the appearance and change in condition were observed with the naked eye. O: Good, Δ: -Poor, × : Evaluated as poor, and the state of defect is noted.

(13) Drying shrinkage rate: Measured according to JIS All 25 (comparator method).

(14) Paint thickness and crack occurrence in steel plate coating: Polymer cement mortar slurry is applied to the steel plate using a nozzle diameter of φ3.2?
With a reshin gun, the coating thickness in one application is 0.0mm at an air pressure of 3.5k91d. Air 1. Go to 3. Painted on h and indoors (25℃60%R)
H) for 7 days, and the presence or absence of cracks on the surface of the film was observed with the naked eye.

(15) Curing time: The initial and final setting times were measured according to JISR-5201-1964.

(16) Recoating time for iron plate coating: (1
Apply the same method as in 3) to a coating thickness of 0.5? Painted inside (25
The time until no marks were left even when the surface of the coating film was left to stand at 65% RH (°C 65% RH) with finger pressure was defined as the time required for overcoating.

The iron plate used in the test was a cold-rolled steel plate that was sandblasted (150 x 70 x 17077 mm).

Claims (1)

[Claims] 1(a) 30 to 70% by weight of vinyl chloride monomer, (b) α
・Alkyl ester of β-unsaturated carboxylic acid (excluding methyl methacrylate) monomer 15-68% by weight, (
c) A polymer obtained by emulsion polymerization of a monomer mixture consisting of 2 to 15% by weight of vinyl acetate monomer in the essential presence of a polyvinyl alcohol derivative having a sulfonic acid group has a glass transition temperature (Tg) of 30 ℃ or less synthetic resin emulsion with quick hardening cement and polymer/cement ratio (
p/c) (weight ratio of polymer to cement) is 0.
A rust- and anti-corrosion coating composition for steel material obtained by mixing in the range of 2 to 0.6 and adding aggregate, surfactant, pigment, and other additives as necessary.