JPS61221464A - Cooling tower - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling tower. For more details,
Excellent stain resistance, weather resistance, and corrosion resistance, 1i! (Relating to a cooling tower that is provided with a protective layer that is resistant to scratches and has excellent transparency and gloss.)

[Conventional technology]

Traditionally, cooling towers have been manufactured from metal, FRP products, or polyvinyl chloride.Since cooling towers are typically installed outdoors, such as on rooftops, and because they allow cooling water to pass through, they are weather resistant, stain resistant, and corrosion resistant. It needs to be good and durable, and preferably aesthetically pleasing.

[Problem that the invention seeks to solve]

Traditionally used metal, FRP or
Cooling towers made of polyvinyl chloride, etc., do not have sufficient corrosion resistance or weather resistance, and their appearance loses gloss over time, gets chipped, gets dirty easily, and also loses its strength, making it less durable. In addition, cooling towers made of metal, FRP, or polyvinyl chloride tend to have algae attached to the wood storage area, and if algae adheres and grows, the pipes are likely to become clogged (or This tends to interfere with normal operation. Therefore, cleaning inside the piping becomes more frequent (and requires a great deal of effort).

The present invention has been made in order to improve the problems of conventional cooling towers as described above, such as insufficient corrosion resistance, antifouling properties, etc., and deterioration of appearance over time.

[Means for solving problems]

The present invention relates to a cooling tower (hereinafter referred to as a cooling tower having a protective layer) provided with a protective layer mainly composed of a vinylidene fluoride copolymer having a functional group and/or a crosslinked product of a vinylidene fluoride copolymer having a functional group. cooling tower).

[Function and Examples]

The protective layer in the present invention is usually formed by applying a fluororesin paint consisting of a polymer composition mainly composed of a vinylidene fluoride copolymer having a functional group (hereinafter referred to as a fluorine-containing copolymer) and a crosslinking agent, Obtained by crosslinking and curing at room temperature. The film thickness is approximately 5 to 100 μm.

The fluorine-containing copolymer has properties that conventional fluororesins do not have, that is, it forms a hard film that hardens at room temperature, and the formed coating film has the weather resistance, stain resistance, and stain resistance that conventional fluororesins have.
It retains its properties such as gloss and corrosion resistance. It also has good adhesion to plastics, metals, and the like. The components, composition, etc. of such a fluorine-containing copolymer are explained in detail in Japanese Patent Application No. 175123/1982.

In the present invention, the fluorine-containing copolymer usually contains 50 to 99 mol% vinylidene fluoride, preferably 65 to 85 mol%, and 1 to 50 mol% vinyl monomer having a functional group, preferably 1 to 10 mol%. or vinylidene fluoride 50 to 99 mol%, preferably 65 to 85 mol%, vinyl monomer having a functional group 1 to 50 mol%, preferably 1 to 10 mol%, and preferably less than 30 mol% of fluoroolefins other than vinylidene fluoride. is comprised of 10 to 25 mol%.

The molecular weight of the fluorine-containing copolymer containing vinylidene fluoride as a main component and having a functional group, as measured by gel permini-silane chromatography (GPC, based on polyethylene), is usually in the range of 10,000 to 500,000.

The vinyl monomer having the above-mentioned functional group usually has the formula: % formula %) (wherein,
represents an integer of θ to 4 (where X is a hydroxyl group, 1 to 4), a compound represented by the formula: %formula%) (wherein, X and n are as above) Compound, formula: %formula%) (wherein, Y is hydrogen or a methyl group, p is an integer of 1 to 4,
X is as defined above, or a compound represented by the formula: %Formula% (wherein, Y is as defined above).

The fluoroolefins other than the vinylidene fluoride mentioned above are usually tetrafluoroethylene, chlorotrifluoroethylene, monofluoroethylene, trifluoroethylene, hexafluoropropene, lower fluoroalkyl vinyl ether, etc., and fluoroethylene is preferred.

The method for producing the fluorine-containing copolymer used in the present invention includes, for example, combining each component in the presence of a solvent using a polymerization catalyst,
Methods such as emulsion polymerization, suspension polymerization or solution polymerization in an aqueous medium at a temperature of -20 to 150°C, preferably 5 to 95°C and a pressure of 0 to 30 kr/ajG, preferably below IOM/cdG are employed. It can be done.

Further, the fluorine-containing copolymer of the present invention has good compatibility with an acrylic resin and can be used in combination with an acrylic resin.

The above-mentioned acrylic resin refers to a single or copolymer of acrylate or methacrylate containing an alkyl group having 1 to 8 carbon atoms. For example, single or copolymers of methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl acrylate, etc., combinations of the above acrylates or methacrylates with hydroxyethyl methacrylate, methacrylic acid, glycidyl methacrylate, etc.
L -7e+r'/ Maka11 rt j L
I+ 71. Commercially available acrylic resins include Hitaloid 3004, Hitaloid 3018, Hitaloid 3046C (all Hitachi Chemical types), Acridic A-810-45, Acridic A314,
Acridic 47-540 (both manufactured by Dainippon Ink and Chemicals) and the like may be mentioned, but are not limited thereto.

The acrylic resin preferably contains 50 weight percent or more of methyl methacrylate and has a molecular weight (GPC) of 5,000 to 300,000 from the viewpoint of compatibility with the fluorine-containing copolymer.

The blending ratio of the fluorine-containing copolymer and acrylic resin is usually 1 part by weight of the fluorine-containing copolymer to 1 part by weight of the acrylic resin.
The amount is 0 to 1900 parts by weight, preferably 25 to 400 parts by weight. When blended within this range, the weather resistance, translucency, and
Good pigment dispersibility etc.

The protective layer in the present invention is usually formed by applying a coating composition obtained by blending a fluorine-containing copolymer with a crosslinking agent and uniformly mixing and dissolving it in an appropriate solvent on the inner and outer surfaces of the cooling tower. It is formed by crosslinking and curing at room temperature. Curing proceeds quickly at room temperature, and a hard coating film is usually obtained in 1 to 10 days, but the time required for curing can be shortened by drying at a temperature raised to a level that does not adversely affect the substrate.

The crosslinking agent is a functional group (
hydroxyl group, carboxyl group or glycidyl group)
It is a compound having two or more groups capable of crosslinking the fluorine-containing copolymer by reacting with the fluorine-containing copolymer.

When the functional group is a hydroxyl group, the crosslinking agent is usually an isocyanate, an acid anhydride, or the like. When the functional group is a carboxyl group, it is usually an isocyanate, an amine, an amino resin, a compound containing a glycidyl group, etc. When the functional group is a glycidyl group, it is usually an amine. Examples of isocyanates include, but are not limited to, hexamethylene diisocyanate, tolylene diisocyanate, hydrogenated tolylene diisocyanate, and block isocyanates thereof. Examples of amines include, but are not limited to, diethylenetriamine, triethylenetetramine, xylene diamine, metaphenylenediamine, benzyldimethylamine, bisaminopropyltetraoxaspiroundecane, etc. Examples of acid anhydrides include phthalic anhydride. Examples of amino resins include, but are not limited to, acids, pyromellitic anhydride, mellitic anhydride, etc., alkyl etherified methylol melamine, alkyl etherified methylol urea,
Examples of compounds containing a glycidyl group include, but are not limited to, alkyl etherified benzoylguanamine, etc. Formula: % Formula % (wherein Z is a glycidyl group, R1 is an alkylene group having 2 to 10 carbon atoms, or Aliphatic diexide or aromatic dieboxide represented by (representing a divalent aromatic group having 6 to 10 carbon atoms), formula: % formula % (wherein R1 is a trivalent aromatic group, Z is the above-mentioned Examples include, but are not limited to, aromatic triepoxides represented by the following formulas.

The amount of the crosslinking agent is preferably adjusted to 0.5 to 2 equivalents based on all the functional groups in the fluorine-containing copolymer and the acrylic resin.

As the solvent, unlike conventional fluorine-containing copolymers, a wide variety of ordinary solvents can be used. Specific examples include esters with ethyl acetate, butyl acetate, isobutyl acetate, cellosolve acetate; acetone, methyl ethyl ketone,
Ketones such as methyl isobutyl ketone; cyclic ethers such as tetrahydrofuran; amides such as N-dimethylformamide and N-dimethylacetamide; alcohols such as methyl alcohol, ethyl alcohol, and butyl alcohol; aromatic carbonization such as toluene and xylene One or more types of hydrogens may be used.

The concentration of the fluorine-containing copolymer varies depending on the coating method and coating manufacturing method, but is usually 5 to 70% by weight, preferably 20 to 60% by weight.

The fluorine-containing copolymer coating composition may optionally contain other polymers, curing accelerators, carbon black or titanium,
Inorganic pigments made of compounds such as zinc, lead, iron, dyes, organic pigments, viscosity modifiers, leveling agents, anti-gelling agents, ultraviolet absorbers such as salicylic acid derivatives, benzophenone compounds, bericitriazole compounds, and light stability. Agents, anti-scald agents, dispersants, antifoaming agents, etc. may be added.

If necessary, the cooling tower made of metal or FRP sil- + polyvinyl chloride may be coated with one or more layers of other layers, such as a wash primer, a commonly used undercoat paint such as epoxy resin paint, or other paints. A protective layer used in the present invention may be formed thereon.

Application to the cooling tower can be carried out by a conventional method such as a spray method, a dipping method, a dipping method, a roll coating method, or a knife coating method.

The cooling tower referred to in this specification includes not only so-called cooling towers for home use, factory use, and office use, but also
The concept also includes outdoor water-cooled or air-cooled heat exchangers. The materials used include unsaturated polyester, epoxy resin, phenolic resin, furan resin, polyamide,
polycarbonate, polyethylene phthalate, etc.
The main products are FRP, FRTP, SMC, BMC, etc., which are composites of fibers such as glass fiber, carbon fiber, asbestos, cotton, hemp, rayon, vinylon, polyester, and acrylic, as well as plastics such as polyvinyl chloride.
The protective layer is not limited to these materials, and may be made of metal such as steel, iron, aluminum, or an alloy thereof, and the location where the protective layer is provided is not limited to the outer periphery of the cooling tower or the water storage area. , a piping section, a support section, a support section, etc.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 V d F 70 mol%, CT F E2G-[-7L,
% and M5F'PIO mol% were added to 50 parts of methyl isobutyl ketone and mixed uniformly, and Coronate EH (manufactured by Nippon Polyurethane Industries Ltd.) was added as a crosslinking agent. Polyisocyanate crosslinking agent) was added in an amount equivalent to the NC0 value of 1.1 of Coronate EH based on the OH value of the fluorine-containing copolymer, and 0.25 g of dibutyltin diurarate as a curing accelerator, and mixed uniformly. A composition was prepared.

On the other hand, a board was prepared by degreasing and cleaning the surface of a polyvinyl chloride board (Kabilon manufactured by Mitsubishi Plastics ■) with a length of 150 mm, width of 70 m, and thickness of 2 M using a fluorocarbon solvent (Guiflon 113 manufactured by Daikin Industries ■). did.

The coating composition was applied to this substrate with a brush to a film thickness of 40.
A coating film of μ steel was formed and cured at 25° C. for 7 days to form a protective layer.

Example 2 A film was made in the same manner as in Example 1, except that the polyvinyl chloride temporary was replaced with a glass fiber-reinforced polyester resin plate (ortho-based polyester manufactured by Dainippon Ink & Chemicals), with a film thickness of 36.
A μ-protective layer was formed.

Example 3 VdF 72 mol%, CTFE 20 moJl/% and M5
Fluorine-containing copolymer consisting of FPIO mol% and MMA
An acrylic resin consisting of 80 mol%, EMAIO mol% and HEMAIO mol% was mixed with methyl isobutyl ketone at a ratio of To/30 (weight ratio) to prepare a 50% by weight festival, and Coronate E was added as a crosslinking agent.
Add H to the OH value 1 of the fluorine-containing copolymer and acrylic resin, the N00 value of Coronae) EH, an equivalent amount of 1.1, and the curing accelerator dibutyltin dilaurate to 1 g of solid content. The mixture was mixed uniformly to prepare a coating composition.

The above coating composition was applied to the substrate of Example 1 and cured in the same manner as in Example 1 to form a protective layer with a thickness of 37 μm.

Example 4 The coating composition of Example 3 was applied and cured on the substrate of Example 20 in the same manner as in Example 1 to form a protective layer with a thickness of 36 μm.

Comparative Examples 1 and 2 The polyvinyl chloride resin plate and the glass fiber reinforced polyester resin plate used in Example 1 and Example 2 were used as samples for Comparative Example 1 and Comparative Example 2, respectively.

The following tests were conducted on the samples obtained in Examples 1 to 4 and Comparative Examples 1 to 2, respectively.

The results are shown in Table 1.

[Contact angle]

One drop each of water and n-cetane was added to the sample, and the contact angle was measured using a goniometer manufactured by Elma Optical ■.

[Accelerated weather resistance]

An accelerated weathering test was conducted for 2,000 hours using a Sunshine Unizer-Ometer manufactured by Suga Test Instruments, with continuous irradiation, a rainfall cycle of 18 minutes/120 minutes, humidity of 60%, and a black panel temperature of 63°C, and the appearance was observed.

[Stain resistance]

1cIa on the surface of the test piece was touched with red Sakuraben (@1
1 (manufactured by Sakura Crepas) and left for 24 hours, then wiped with tissue paper impregnated with ethanol methyl ethyl ketone (9/1 weight ratio) and observed the appearance of the test piece surface. , × indicates that the red color remained and could not be removed.

Table 1 Examples 5 to 6 The coating compositions prepared in Examples 1 and 3 were applied to a part of the outer peripheral surface and a part of the water storage part of a cooling tower made of glass fiber reinforced polyester resin in the same manner as in Example 1. A protective layer was formed.

After 6 months had passed, there was no change in the painted part of the outer circumferential surface, but chiller king had already occurred in the unpainted part, and the gloss had decreased significantly. Also, there was less deposits on the painted part of the water storage area compared to the unpainted part.

Examples 7 to 23 A fluorine-containing copolymer or a fluorine-containing copolymer and an acrylic resin (the proportions are shown in Table 2) having the compositions shown in Table 2 were dissolved in methyl isobutyl ketone, and the solid content concentration was 30
I adjusted it so that the weight was 9.

An amount equivalent to 1.1 in the NGO price of Coronate EH and dibutyltin silaudirate were added to 1 g of the solid content in an amount of 1X10-''g per 1 OH value of the dissolved solid content, and mixed thoroughly, followed by Example 2. A similar glass fiber-reinforced polyester resin board was coated and cured for 7 days at room temperature.The resulting cured coatings were approximately 23 to 29μ thick.
It was a hard, glossy coating film.

Tests were carried out for $t & material A, respectively, culture contact resistance and turbidity. The results are shown in Table 2.

In addition, each abbreviation represents the following compound.

VdF: vinylidene fluoride CTFE: chlorotrifluoroethylene TFE
: Tetrafluoroethylene M5FP: CFf
fi ro CFCF snow CH goose OH3F HA: CF
z -CF CHz CH* OHHBVE: Hydroxybutyl vinyl ether GVE: Glycidyl vinyl ether 7FHA: CFz-CFCF
tCFtCH*CHz OH MMA: Methyl methacrylate EMA:
Ethyl methacrylate HEMA: Hydroxyethyl methacrylate HMA: Butyl methacrylate MA: Methacrylic acid GMA: Glycidyl methacrylate 5 F B
A: CF z -CF CF z COOH [
Weather resistance] A test piece was attached to the cooling tower of Examples 5 to 6,
Inspected the exterior after 6 months.

〔Effect of the invention〕

A polymer composition whose main component is a vinylidene fluoride copolymer having a functional group can be cured at room temperature, and can be used to create a coating film with excellent weather resistance, stain resistance, gloss, etc. for various types of cooling tower substrates. Therefore, the cooling tower having the protective layer of the present invention in which the coating film is provided as a protective layer exhibits extremely excellent weather resistance, stain resistance, appearance, durability, etc.

Claims (1)

[Claims] 1. Vinylidene fluoride copolymer having a functional group and/or
Or a cooling tower provided with a protective layer mainly composed of a crosslinked vinylidene fluoride copolymer having a functional group.