JPS6187064A - 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,
It has excellent stain resistance, weather resistance, and corrosion resistance, is hard and scratch resistant, and has excellent transparency and gloss. The present invention relates to a cooling tower provided with layers.

[Prior Art] Conventionally, cooling towers made of metal, FRP, polyvinyl chloride, or the like have been manufactured and used.

Since cooling towers are generally installed outdoors, such as on rooftops, and because they allow cooling water to pass through, they need to be durable, have good weather resistance, stain resistance, and corrosion resistance, and are preferably aesthetically pleasing.

[Problems to be solved by the invention: Cooling towers made of metal, FRP, or polyvinyl chloride that have been used in the past do not have sufficient corrosion resistance or weather resistance, and their appearance deteriorates over time. However, chalking may occur and stains may occur easily. Moreover, since the strength is also reduced, the durability is not sufficient. Moreover, metal and FRP
Cooling towers made of plastic or polyvinyl chloride tend to have algae attached to the water storage area, and when algae adheres and grows, the piping becomes sticky, which can easily interfere with normal operation. Therefore, cleaning inside the piping and the like 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, such as insufficient corrosion resistance, weather resistance, antifouling properties, etc., and deterioration of appearance over time.

[Means for solving the problems] The present invention provides (ω chlorotrifluoroethylene (hereinafter referred to as CTFE) or tetrafluoroethylene (hereinafter referred to as TFE), (b + fluoro lower alkyl vinyl ether and (c
) The present invention relates to a cooling tower provided with a protective layer containing a crosslinked copolymer mainly composed of hydroxyalkyl vinyl ether (hereinafter referred to as a cooling tower having a protective layer).

[Function and Examples] The protective layer in the present invention comprises (ω component, +b+ component, and (c
) component (hereinafter referred to as fluorine-containing copolymer) and a crosslinking agent, and crosslinking and curing at room temperature obtains a film thickness of 5 to 100 mm. It is of a certain degree.

The fluorine-containing copolymer has properties that conventional fluororesins do not have, namely, it cures at room temperature to form a hard film, and the formed coating 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. Regarding each component, composition, etc. of such a fluorine-containing copolymer, see Japanese Patent Application No. 58-63399 and Japanese Patent Application No. 1983.
It is explained in detail in the specification of No. 8-175123.

Among them, as component (b), particularly preferred are alkyl vinyl ethers in which the alkyl group has 1 to 10 carbon atoms, and in which the hydrogen atoms of the alkyl group are partially or completely substituted with fluorine atoms. Specific examples include 2,2,2-trifluoroethyl vinyl ether,
2,2,3.3-Tetrafluoropropyl vinyl ether, 2,2°3,3.3-pentafluoropropyl vinyl ether, 2,2.3.3.4.4.5.5-octafluoropentyl vinyl ether, 2 ,2,3,3,4
, 4,5,5,6,6,7,7,8,8,9°9-hexadecafluorononyl vinyl ether.

In addition, as component (c), the alkyl group has 2 to 1 carbon atoms.
Particularly preferred is zero. Specific examples include hydroxybutyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether,
Examples include 1-methyl-3-hydroxypropyl vinyl ether.

The fluorine-containing copolymer in the present invention has (ω component unit 40
~60 mol%, (b) component unit 5-50 mol%, (c)
Those containing 0.5 to 40 mol% of component units are preferable, especially (ω component units 40 to 60 mol%, +b+ component units 20
-45 mol%, preferably containing 1 to 30 mol% of (c) component units. In addition, as long as the desired characteristics are not impaired,
Other ethylenically unsaturated monomers may be copolymerized. Examples of copolymerizable ethylenically unsaturated monomers include ethylene, propylene, isobutylene, vinyl acetate, vinyl chloride, vinylidene chloride, (meth)acrylic acid, and (meth)acrylic acid ester.

As a method for producing the fluorine-containing copolymer used in the present invention, for example, the ω component, the (b) component and the (c) component are mixed using a polymerization catalyst in the presence of a solvent at -20 to 150°C, preferably at 50°C. Temperature of ~95℃ and 0-30g/cm2
Methods such as emulsion polymerization, suspension polymerization or solution polymerization in an aqueous medium under pressure conditions of less than 10 g/ca2 G may be employed.

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 raising the temperature to a level that does not adversely affect the substrate.

Examples of the crosslinking agent include compounds having two or more functional groups that can react with the hydroxyl groups contained in the fluorine-containing copolymer, and cure the copolymer by reacting with the hydroxyl groups.

Specific examples of the crosslinking agent include hexamethylene diisocyanate, derivatives such as its trimer, xylylene diisocyanate, tolylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated -4,4°-diphenylmethane diisocyanate, block type isocyanate, etc. Examples include isocyanates, acid anhydrides, polyvalent amines, amine resins, and compounds having epoxy groups. The amount of the crosslinking agent is preferably adjusted to 0.5 to 2 equivalents per hydroxyl group in the fluorine-containing copolymer.

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

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, etc., organic pigments, dyes, viscosity modifiers, leveling agents, anti-gelling agents, ultraviolet 11 absorbers such as salicylic acid derivatives, benzophenone compounds, bericitriazole compounds, and light resistance. stabilizer,
Anti-scald agents, dispersants, antifoaming agents, etc. may be added.

Additionally, if necessary, the cooling tower made of metal, FRP, polyvinyl chloride, etc. is provided with one or more layers of other layers, such as a wash primer, a commonly used undercoat such as epoxy resin paint, or other paint. 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,
FRP, FRTP, SHC, BHC, which are composites of polycarbonate, polyethylene terephthalate, etc., and fibers such as glass fiber, carbon fiber, asbestos, cotton, hemp, rayon, vinylon, polyester, acrylic, etc.
The main materials are plastics such as polyvinyl chloride, etc., but are not limited to these, for example, steel,
It may be a metal such as iron, aluminum or an alloy thereof. Further, the location where the protective layer is provided is not limited to the outer peripheral part of the cooling tower and the water storage part, but may be in parts such as the piping part, the support part, and the support part.

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

Example 1 50 parts (parts by weight, same hereinafter) of a fluorine-containing copolymer consisting of 50 mol% CTFE, 40 mol% 2,2,3.3-tetrafluoropropyl vinyl ether, and 10 mol% hydroxybutyl vinyl ether were mixed with acetic acid n -Butyl 3
5 parts, 10 parts of xylene and 5 parts of methyl isobutyl ketone.
and 50 parts of a mixed solvent and mixed uniformly, and further 9 parts of Coronate EH (polyisocyanate crosslinking agent for non-yellowing paint manufactured by Nippon Polyurethane Industries) as a crosslinking agent (equivalent ratio: 1.0). The mixture was added and mixed uniformly to prepare a coating composition.

On the other hand, length 100+a+a, width 50au, thickness 21
m polyvinyl chloride board (Kabiron manufactured by Mitsubishi Plastics ■)
A substrate was prepared by degreasing and cleaning the surface with a fluorocarbon solvent (Daiflon 113 manufactured by Daikin Industries, Ltd.).

The coating composition was applied to this substrate using a spatula, and the film thickness was 40.
A coating film of AIITl was formed and cured at 25° C. for 7 days to form a protective layer.

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

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 and 2 and Comparative Examples 1 and 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 Weathering Resistance] Using a Sunshine Weather-Ometer manufactured by Suga Test Instruments, we conducted an accelerated weathering test for 2,000 hours under continuous irradiation, rainfall cycle of 18 minutes/120 minutes, humidity of 60%, and black panel temperature of 63°C. observation.

[Stain resistance]

IC12 on the surface of the test piece was painted over with red Sakura Bentouch (■ manufactured by Sakura Crepas) and left for 24 hours, then wiped off with tissue paper impregnated with ethanol and the appearance of the surface of the test piece was observed. In the table, O indicates that it was completely removed, and X indicates that red color remained and could not be removed.

Table 1 Example 3 The coating composition prepared in Example 1 was applied to a part of the outer peripheral surface and 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 to form a protective layer. was formed.

After 6 months, there was no change in the painted part of the outer circumferential surface, but chalking 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 4 to 8 A fluorine-containing copolymer having the composition shown in Table 2 was dissolved in a mixed solvent of methyl ethyl ketone and butyl acetate (weight ratio 1/1), and the copolymer concentration was adjusted to 20% by weight. did. Dismodur TP, which is a hexamethylene diisocyanate trimer, as a crosslinking agent for 100 parts of the solution.
- to L5-2444 (manufactured by Sumitomo Bayer ■) 50% by weight
After adding and thoroughly mixing 7 parts of the methyl ethyl ketone solution and 1 part of triethylamine, the mixture was applied to a glass fiber reinforced polyester resin board similar to that in Example 2, and cured at room temperature for 7 days. The cured coatings obtained were all glossy, hard coatings with a thickness of about 28 to 33 mm.

Each sample was tested for contact angle, weather resistance, and stain resistance. The results are shown in Table 2.

In addition, each abbreviation in Table 3 represents the following compound.

3FVE: 2,2,2-trifluoroethyl vinyl ether 4FVE: 2,2,3.3-tetrafluoropropyl vinyl ether 5FVE: 2,2,3,3.3-penta7/L/
t O Propyl vinyl ether 8FVE: 2,2,3,3,4,4,5.5-octafluoropentyl vinyl ether HBVE: Hydroxybutyl vinyl ether [Weather resistance] A test piece was attached to the cooling tower of Example 3, and then heated for 6 months. Observe the appearance after the passage of time.

[Margin below]

[Effects of the Invention] As described above, the fluorine-containing copolymer containing the (ω, +b) and (c) components as main components can be cured at room temperature,
Moreover, since a coating film with excellent weather resistance, antifouling properties, gloss, etc. can be formed regardless of the type of cooling tower base material, the protective layer of the present invention, in which the coating film is provided as a protective layer, can be used. The cooling tower has excellent weather resistance, antifouling properties, appearance, and durability.

Claims (1)

[Scope of Claims] 1. A protective layer containing a crosslinked product of a copolymer mainly composed of (a) chlorotrifluoroethylene or tetrafluoroethylene, (b) fluoro lower alkyl vinyl ether, and (c) hydroxyalkyl vinyl ether is provided. Cooling tower that will be used.