JPS6233365B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an effective antifouling method for seawater contact surfaces formed of concrete or mortar of cooling water system structures and equipment that use seawater in power plants. Due to geographical constraints, most of the thermal and nuclear power plants that form the main source of electricity generation in Japan are built on coastal areas and use seawater as cooling water. As a result, marine fouling organisms (hereinafter referred to as fouling organisms), especially animals such as mussels and barnacles, adhere to the surfaces of structures and equipment in the power plant cooling water system that come in contact with seawater, grow, and cause blockage of the water flow path. ,
Power generation efficiency is reduced due to a decrease in water intake and deterioration of cooling efficiency, and these fouling organisms enter the condenser cooling pipes, causing cuts and perforations, causing power generation to stop. Conventionally, measures to prevent the adhesion of the above-mentioned fouling organisms (hereinafter referred to as antifouling) include (1) physical methods (ultrasonic waves, high frequency waves, low-toned seawater methods, etc.), and (2) chemical injection methods (copper sulfate, picrin, etc.). (3) Injecting chlorine gas (or electrolytic chlorine); (4) Applying cuprous oxide antifouling paint; however, method (1) is not practical due to its effectiveness and difficulty in implementation. method (2) is not practical due to the impact on marine life and economic efficiency, and method (3) has been put to practical use in Japan because it is easy to manage, but Since the decomposition behavior of chlorine changes depending on alkalinity and dirt, in reality, the antifouling effect is insufficient, but useful plankton are killed at the same time as the larvae of fouling organisms near the chlorine injection point. Unlike methods (1), (2), and (3), which involve a large amount of cooling water as a whole, method (4) is more rational and effective because it is a method that prevents stains on the surface. However, since cuprous oxide type antifouling paints are non-dissolving matrix type paints, the elution rate of the antifouling agent rapidly decreases and the antifouling power is lost in a short period of time. The elution rate of an effective antifouling agent requires at least 10 times the elution rate of the triorganotin antifouling agent. Furthermore, copper ions do not decompose or become non-toxic, so if they are used in a specific sea area for a long time,
Copper ions accumulate. There are drawbacks such as. In order to solve these problems, the present inventors proposed a cooling water system antifouling method using an antifouling coating agent mainly containing an organic tin polymer, in Japanese Patent Application No. 56-78612.
This was proposed as patent application No. 189898, 1983. In these inventions, when the organic tin polymer that serves as the antifouling coating agent is applied to an object, the organic tin monomer that serves as the antifouling component is chemically bonded to the acrylic resin, so that it is integrated with the resin. However, when it comes into contact with seawater, the ions gradually dissociate to regenerate the antifouling agent (triorganotin ions) while the resin itself also dissolves away. That is, as shown in the formula below, the dissociated triorganotin ions act as an antifouling agent and prevent the attachment of fouling organisms. Therefore, the above method (1) maintains a constant antifouling power for a long period of time; In other words, the coating film thickness and the antifouling period are approximately proportional. (2) The elution rate of the antifouling agent can be controlled to the necessary minimum, which is advantageous in terms of pollution control. (3) The dissolved antifouling agent decomposes and becomes non-toxic under the action of ultraviolet rays, ozone, oxygen, etc., and eventually turns into harmless inorganic tin, so unlike cuprous oxide, the antifouling agent accumulates. There's nothing to do. This is an excellent method. However, when an organotin polymer antifouling coating is applied directly to concrete or mortar, the coating film dissolves from both the contact surface with seawater and the contact surface with concrete or mortar, as concrete or mortar is usually strongly alkaline. As a result, the coating film peels off in a short period of time, and the excellent antifouling power of the organic tin polymer antifouling coating agent cannot be exhibited. As a result of intensive research on this point, the present inventors have found that epoxy resins, vinyl chloride resins, and chlorinated polyolefin resins (ethylene and propylene as olefins) as basic resins for primer coating agents have good adhesion to concrete or mortar. The present invention was completed based on the discovery that it is strong, blocks alkali leaching, and has excellent adhesion to organic tin polymer antifouling coatings. In other words, the present invention is applicable to structures and systems of power plant cooling water systems.
Seawater contact surfaces made of concrete or mortar on equipment are pre-applied with epoxy equivalent.
Primer coating agent containing an epoxy resin in the range of 180 to 3300, vinyl chloride with a vinyl chloride content of 91% by weight or less and a vinyl acetate content of 34% by weight or less,
After applying a primer coating agent containing a vinyl resin that is a vinyl acetate copolymer or a primer coating agent containing a chlorinated polyolefin resin with a chlorine content of 66% by weight or more, the general formula (In the formula, R represents an alkyl group or phenyl group having 3 to 5 carbon atoms, and R' and R'' represent a hydrogen atom or a methyl group.) A polymer or copolymer of an unsaturated organotin monomer, Or concrete characterized by applying an antifouling coating agent containing a copolymer of the unsaturated organotin monomer represented by the formula [A] and another copolymerizable unsaturated compound as a main component. and an antifouling method for mortar surfaces.The undercoating agent used in the present invention has strong alkali resistance, good adhesion to concrete or mortar, blocks leaching alkali, and also contains an organic tin polymer antifouling agent. It has excellent adhesion to the coating film, a characteristic that cannot be obtained with coating agents used as ordinary non-coating coating agents. Among the resins used in the undercoat coating agent used in the present invention, For epoxy resin, epoxy equivalent 180
~3300, such as Epicote 807, 815, 815×A manufactured by Yuka Ciel Epoxy Co., Ltd.
816, 819, 827, 828, 828×A, 834, 871, 872,
1001, 1002, 1003, 1055, 1004, 1007, 1009, etc., or epoxy resins equivalent to these types. A curing agent whose main ingredient is an epoxy resin containing one or more selected from these, and a curing agent containing one or more combinations selected from amine, amine adduct, amide, amide adduct, polyamide resin, etc. and mix immediately before use to form a primer coating agent. Note that it is desirable that the mixing ratio of the base agent and the curing agent be stoichiometrically equal. The reason why the epoxy equivalent is limited to a range of 180 to 3300 is that if the epoxy equivalent is less than 180, the molecular weight between crosslinks is too small, resulting in rigidity and poor adhesion to concrete or mortar and the organotin polymer antifouling coating film. In addition, if the epoxy equivalent is 3300 or more, the molecular weight is large and the crosslinking reaction with the curing agent is too slow. Also, when preparing the base coating agent, the viscosity is high and the solid content is low, resulting in a problem with the coating film thickness. This is because it is not preferable in practice, as it lowers the value. Regarding vinyl resin, the content of vinyl chloride is
Vinyl resins with a vinyl acetate content of 91% by weight or less and 34% by weight or less, such as Vinylite VYHH, VYHD, manufactured by Union Carbide;
VYLF, VYNS-3, VAGH, VAGD, VROH,
VMCH, VMCC, VMCA, VERR-40, VYDS,
VYDS-66, VYNC, or their equivalents, and one or a mixture of two or more of these is used as a primer coating agent. Here, the content of vinyl chloride in vinyl resin is 91
The reason for setting the vinyl acetate content below 34% by weight is that if it is 91% by weight or more, the adhesion to concrete or mortar and the organic tin polymer antifouling coating film becomes weak when used as a primer coating agent. The reason for setting the content to be less than 34% by weight is that alkali resistance becomes weaker when the content is more than 34% by weight, and the undercoat film easily peels off from the concrete or mortar. The chlorinated polyolefin resin is a chlorinated polyethylene resin or a chlorinated polypropylene resin with a chlorine content of 66% by weight or more, such as Super Chron 907MA manufactured by Sanyo Kokusaku Pulp Co., Ltd.
907LL, 106H, 307, 406, 507 or equivalent products, which are used as a primer coating agent. The reason why the chlorinated polyolefin resin is selected as chlorinated polyethylene resin or chlorinated polypropylene resin is that chlorinated polybutylene resin, chlorinated polyamylene resin, chlorinated polyhexylene resin, etc. are used in order to uniformly perform the chlorination reaction. This is because it is necessary to reduce the molecular weight of the olefin resin, and as a result, the toughness of the coating film is inhibited, causing cracks, etc., and inhibiting the adhesion with concrete or mortar. It also reduces the chlorine content to 66% by weight.
The reason for this is that if the chlorine content is less than 66% by weight, stability is poor, and the primer coating film may deteriorate due to dechlorination or dehydrochlorination reactions and may peel off from the concrete or mortar. This is because the generated chlorine etc. have an adverse effect on the organic tin polymer antifouling coating film, making it difficult to maintain stable performance over a long period of time. These resins for undercoating are dissolved in a suitable solvent, and if necessary, a plasticizer, pigment, stabilizer, coal tar, etc. are added thereto, and kneaded by a conventional method to obtain an undercoat. In addition, the organic tin polymer antifouling coating agent applied as a top coat has the general formula (In the formula, R represents an alkyl group having 3 to 5 carbon atoms or a phenyl group, and R' and R'' represent a hydrogen atom or a methyl group.) For example, tripropyltin, tributyltin, triamyltin, triphenyltin, etc. Polymers of acrylate or methacrylate of triorganotin compounds or unsaturated compounds copolymerizable with the unsaturated organotin monomer represented by this formula [A], such as methyl acrylate, ethyl acrylate, butyl acrylate, acrylic Acrylic esters such as octyl methacrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, or unsaturated compounds such as styrene and vinyltoluene, and formula [A]
A coating agent whose main component is a polymer obtained by copolymerizing with an unsaturated organotin monomer shown in and use it as a liniment. The organic tin polymer antifouling coating agent is applied using the same method as the base coating agent, but the coating film thickness depends on the flow rate, pH, and temperature of the seawater used as cooling water, and the required durability. It should be determined by the age (duration of antifouling power) and the elution rate of the antifouling agent, and 30 μ or more is required based on a one-year service life. According to the antifouling method by combining the thus obtained undercoat coating agent with excellent alkali resistance and the organic tin polymer antifouling coating agent of the present invention, the leaching of alkali is essentially prevented, and the stain resistant coating agent can be applied as a top coat. The organic tin polymer antifouling coating film can be prevented from peeling off from the concrete or mortar substrate, and long-term antifouling that is advantageous in terms of pollution control can be achieved. Next, the present invention will be explained in detail using Examples and Comparative Examples. Unless otherwise specified in the text, parts are parts by weight. Preparation of organotin polymer antifouling coating agent (A) In a flask equipped with a stirrer, add 112 g of tributyltin methacrylate, 65 g of methyl methacrylate,
Prepare a mixture of 10 g of butyl acrylate, 23 g of octyl acrylate, 1.2 g of benzoyl peroxide, and 200 g of xylene, and
Copolymerization was carried out by heating and stirring at 90°C for 2 hours, then at 100°C to 1050°C for 3 hours, and further heating and stirring at 120°C for 1 hour. The obtained copolymerization solution was colorless and transparent, and had a viscosity of 660 cps at 25°C. The obtained copolymer solution was blended with other components in the amounts shown below and kneaded to prepare an organic tin polymer antifouling coating agent (A). Copolymer solution 40.0 parts Titanium dioxide 10.0 parts Phthalocyanine blue 20 parts Talc 34.5 parts Xylene 13.5 parts Preparation of base coating agents A to H The main ingredients of A to H whose formulations are shown in Table 1 were kneaded, and further A to D Example basecoat applications A to H were prepared by adding a curing agent just before use.

【table】

[Table] Preparation of Comparative Example Primer Coating In a flask with a stirrer, 10.8 parts of rosin, 30.6 parts of Tamanol 145F (rosin-modified phenolic resin manufactured by Arakawa Hayashi Sangyo), 14.0 parts of linseed oil, 1.6 parts of Chinese tung oil, and 10.0 parts of mineral spirits. Section, Swazol J310 (aromatic petroleum naphtha manufactured by Maruzen Oil Co., Ltd.)
33.0 parts were charged and stirred for 1 hour while heating to 50°C to obtain a transparent denatured oil solution colored slightly brown. A comparative base coat coating agent was prepared using a modified oil solution according to the following formulation. Talc 20.0 parts Baryta 3.6 parts Valve handle 8.0 parts Zinc white 4.0 parts Modified oil solution 57.9 parts Cobalt naphthenate 0.3 parts Lead naphthenate 3.0 parts Mineral spirits 3.2 parts Examples 1-8, Comparative Examples 1-2 Primer coating agent A~ was spray-coated 2 to 3 times on each of three mortar-finished concrete plates to the coating thickness shown in Table 2, and an organic tin polymer antifouling coating was applied on top of Comparative Example 1, which had not been undercoated. Coated test plates of Examples 1 to 8 and Comparative Examples 1 to 2 were prepared by spray coating coating agent (A) twice at a coating thickness of 60 μm. One coated test board for each example and comparative example is 40
The adhesion was examined over time by immersing it in artificial seawater at ℃.
The other two photos are from Yura Bay, Shumoto City, 1.5m below the water surface from the raft.
The antifouling effect and adhesion were examined over time by immersing the material in the sea. The results are shown in Tables 3, 4, and 5.

【table】

[Table] As shown in Table 3, Examples 1 and 2 were coated with primer coating agents A and B containing epoxy resin, and primer coating agents C and D, which are generally called tar epoxy resin coating agents, were coated in advance. Example 3 and Example 4 were coated, Example 5 and Example 6 were coated with primer coating agents E and F containing vinyl resin, Example 7 were coated with primer coating agent G containing chlorinated polyethylene, and chlorine. In Example 8, in which primer coating agent H containing chemically modified polypropylene was applied, there were no abnormalities in the goblin test after 6 months of immersion in artificial water at 40°C, showing good adhesion. Coating agent (A)
In Comparative Example 1, in which the material was applied directly to the concrete board, and in Comparative Example 2, in which a comparative undercoat paint, generally called oil-based undercoat paint, was applied, the goblin test conducted before immersion in artificial seawater at 40°C was 25, which was normal. However, in Comparative Example 1, the coating film completely peeled off after 1 month of immersion, and in Comparative Example 2, after 3 months of immersion, and the epoxy resin,
It was shown that tar epoxy resin, vinyl resin, and chlorinated polyolefin resin have strong adhesion to concrete or mortar and have excellent alkali resistance.

【table】

[Table] The results in Table 4 are expressed as the adhesion rate of fouling organisms to the total area of the test plate, but essentially they are based on the presence or absence of an undercoat (no undercoat was applied in Comparative Example 1). This is due to the difference in adhesion to the concrete or mortar base due to the difference in the type of primer coating agent (in Comparative Example 2, an oil-based primer paint with weak alkali resistance was used as the primer coating agent), and this tendency is shown in Table 1. The results are similar to those of the eye test.

【table】

[Table] The results in Table 5 have the same tendency as the results in Tables 3 and 4, indicating that the primer used in the present invention has alkali resistance and has excellent adhesion to concrete or mortar. Indicated. Example 9 Primer coating agents A and B were applied to 50% of the area to be coated on the mortar-finished concrete water intake wall of power plant A, each with a film thickness of 50 μm.
2 times, and then apply organic polymer antifouling coating agent (A) to a film thickness of 60 mm.
μ was applied twice over the entire surface using an airless sprayer. When investigated after one year of water flow, there was no peeling of the coating film or adhesion of fouling organisms, indicating good antifouling ability. Example 10 Primer coating agents C and D were applied twice to 50% each of the area to be coated on the inner surface of the circulating water pipes lined with mortar at power plant B, each with a film thickness of 70 μm, and then an organic tin polymer antifouling agent was applied. Coating agent (A) was applied twice to the entire surface with a coating thickness of 60 μm using a roller brush. When investigated after 2 years of water flow, there was no peeling of the coating film or adhesion of fouling organisms, indicating good antifouling properties. Example 11 Primer coating agents E and F were applied three times to 50% each of the area to be coated on the concrete water intake wall of power plant C, each with a film thickness of 30 μm, and then an organic tin polymer antifouling coating agent ( A) was applied twice to the entire surface with a coating thickness of 60 μm using an airless sprayer. When investigated after one year of water flow, there was no peeling of the coating film or adhesion of fouling organisms, indicating good antifouling ability. Example 12 Primer coating agents G and H were applied twice to 50% each of the area to be coated on the inner surface of the circulating water pipes lined with mortar at power plant D, each with a film thickness of 40 μm, and then an organic tin polymer antifouling agent was applied. Apply coating agent (A) at 60 μ over the entire surface.
It was applied twice using a roller brush. When investigated after one year of water flow, there was no peeling of the coating film or adhesion of fouling organisms, indicating good antifouling ability. Comparative Example 3 On a part of the inner surface of the mortar-lined circulating water pipe in power plant B, organic tin polymer antifouling coating agent (A) was applied twice to a film thickness of 60μ at one location, and at the other location. A comparative undercoat coating agent was applied twice at a coating thickness of 40 μm, and an organic tin polymer antifouling coating agent (A) was applied twice at a coating thickness of 60 μm using a roller brush. When we observed the condition after one year of water flow, we found that the coating film had completely peeled off and disappeared.
Fouling organisms were adhered to the entire surface. As explained above in the Examples and Comparative Examples, the antifouling method of the present invention applies an epoxy resin undercoat to the concrete or mortar contact surfaces of power plant cooling water system structures and equipment. By overcoating a vinyl resin-based primer coating agent or a chlorinated polyolefin (olefin: ethylene or propylene) resin-based primer coating agent and an organic tin polymer antifouling coating agent, the antifouling power and adhesion of the coating film can be improved. Both are industrially useful and can be expected to have long-term effects.

Claims (1)

[Claims] 1. The seawater contact surface formed of cooling water-based concrete or mortar has an epoxy equivalent of 180
A base coat containing an epoxy resin in the range of ~3300, a vinyl chloride/vinyl acetate copolymer with a vinyl chloride content of 91% by weight or less and a vinyl acetate content of 34% by weight or less After applying a primer coating agent containing a resin or a primer coating agent containing a chlorinated polyolefin resin with a chlorine content of 66% by weight or more, the general formula (In the formula, R represents an alkyl group or phenyl group having 3 to 5 carbon atoms, and R' and R'' represent a hydrogen atom or a methyl group.) A polymer or copolymer of an unsaturated organotin monomer, Or concrete characterized by applying an antifouling coating agent containing a copolymer of the unsaturated organotin monomer represented by the formula [A] and another copolymerizable unsaturated compound as a main component. and antifouling methods for mortar surfaces.