JP2009235403A - Epoxy resin-based coating material for corrosion prevention and method for preventing deterioration of water supply construction using the coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin-based coating material for corrosion prevention having excellent corrosion preventing properties (chemical resistance) to acid components such as inorganic acids and organic acids which are included in sewage and waste water flowing and storing in a water supply construction. <P>SOLUTION: The epoxy resin-based coating material for corrosion prevention comprises (A) an epoxy resin, (B) an epoxy adduct-modified aromatic amine-based curing agent and (C) a mesitylene resin and/or a xylene resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anticorrosion epoxy resin-based paint and a method for preventing deterioration of a water use structure using the paint.

Conventionally, it has been found that deterioration of irrigation structures such as sewage-related facilities is caused by a dissolution deterioration phenomenon caused by a strong acid component. This phenomenon occurs after hydrogen sulfide is generated from the sewage sulfate by anaerobic sulfur-reducing bacteria in the sludge, and the generated hydrogen sulfide is released into the air and dissolved in the condensed water on the surface of the water use structure. The main cause is that sulfuric acid, which is a strong acid component, is produced by aerobic sulfur-oxidizing bacteria.
Moreover, the deterioration phenomenon of the building pit, which is a water use structure for temporarily storing sewage generated in a commercial / office building, a hotel or other structure or facility, is more remarkable than in a public sewerage facility. This is due to organic sludge drainage containing food residues, oils or cleaning agents that flow into the building pits. Furthermore, 40-50 ° C hot wastewater flows constantly, so the deterioration phenomenon is accelerated. Proceed to.

As a method for preventing / suppressing the deterioration phenomenon of such a water use structure, a method of applying a heavy anticorrosion paint such as a vinyl ester resin paint, a polyurea resin paint, an epoxy resin paint or the like is used.
However, in the case of vinyl ester resin-based paints, since a styrene monomer-containing product is generally used, there is a problem of styrene odor. In recent years, non-styrene type vinyl ester resin-based paints have been developed, but there are many problems to be solved, such as cost, anticorrosion performance, and dryness of the coating surface.
In addition, in the case of polyurea resin-based paints, it can be applied by spray-up, and while it is an anticorrosion paint with excellent workability, it has been confirmed that there are floating and peeling phenomena due to sulfate in sewage, and problems with anticorrosion performance are evident. It has become.
Further, in the case of epoxy resin-based paints, the anticorrosion performance has been remarkably improved in recent years, and the results of having sufficient anticorrosion performance in the use of general sewers have been reported. However, it cannot be said that it has sufficient anticorrosion performance for organic sludge drainage containing organic acid components such as acetic acid and formic acid in the building pit.
Further, Patent Document 1 discloses an iron pipe coating composition containing a xylene resin. The coating composition is improved in flexibility, impact resistance and flexibility by adding xylene resin, but chemical resistance (corrosion resistance) is not sufficient, especially chemical resistance against organic acids. However, it is difficult to use in a building pit where wastewater containing organic acid flows in and stores.

Japanese Patent Publication No. 3-12591

  In view of the above circumstances, the problems to be solved by the present invention are sewage flowing into and stored in a water conserving structure, inorganic acids contained in drainage, and acid components such as organic acids generated by the decomposition of oil and cleaning agents. It is an object of the present invention to provide an anticorrosion epoxy resin paint having excellent anticorrosion properties (chemical resistance) against the above.

  As a result of intensive studies to solve the above problems, the present inventors have (A) an epoxy resin, (B) an epoxy adduct-modified aromatic amine-based curing agent, (C) a mesitylene resin and / or xylene. The present invention has been completed by finding that an anticorrosive epoxy resin paint containing a resin has excellent anticorrosive properties (chemical resistance) against acid components such as inorganic acids and organic acids contained in sewage and wastewater. It was.

That is, the present invention is as follows.
[1]
(A) an epoxy resin;
(B) an epoxy adduct-modified aromatic amine curing agent;
(C) a mesitylene resin and / or a xylene resin;
Epoxy resin paint for corrosion protection.
[2]
The anticorrosion epoxy resin paint according to the above [1], comprising 20 to 60% by mass of the component (A), 10 to 30% by mass of the component (B), and 3 to 10% by mass of the component (C). .
[3]
A method for preventing deterioration of a water use structure, comprising a step of applying the anticorrosion epoxy resin paint according to the above [1] or [2] to an inner surface of the water use structure.

The epoxy resin coating for anticorrosion of the present invention is excellent for acid components and cleaning agents such as sewage that flows into and stores in irrigation structures, inorganic acids contained in wastewater, organic acids generated by decomposition of oil, and the like. Has anticorrosive properties.
In addition, the method for preventing deterioration of a water use structure according to the present invention can impart excellent corrosion resistance to acid components to the water use structure, so that the deterioration phenomenon of the water use structure can be remarkably prevented / suppressed. .

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  The anticorrosion epoxy resin paint of this embodiment contains (A) an epoxy resin, (B) an epoxy adduct-modified aromatic amine-based curing agent, and (C) a mesitylene resin and / or a xylene resin.

  The anticorrosion epoxy resin coating of the present embodiment has a synergistic effect of (B) reduction of free amine by an epoxy adduct-modified aromatic amine curing agent and (C) hydrophobicity by mesitylene resin and / or xylene resin. , Remarkable improvement in corrosion resistance (hereinafter also referred to as chemical resistance) has been achieved.

[(A) component: epoxy resin]
Various epoxy resins can be used as the (A) epoxy resin contained in the anticorrosive epoxy resin paint of the present embodiment, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin. In addition, known epoxy resins such as bisphenol AD type epoxy resins and epoxy resins obtained by modifying them can be used. Among these, a polyfunctional epoxy resin is preferable from the viewpoint of improving the corrosion resistance (chemical resistance) due to the crosslink density, and a bifunctional epoxy resin is preferable from the viewpoint of a balance of viscosity, wear resistance, and mechanical strength.

  Although it does not specifically limit as content of (A) epoxy resin in the epoxy resin-type coating material for anticorrosion, Preferably it is 20-60 mass%, More preferably, it is 40-50 mass%. (A) When the content of the epoxy resin is more than 60% by mass, the workability tends to be remarkably lowered with the increase in the viscosity of the epoxy resin paint for anticorrosion. Performance (chemical resistance) is lowered, and the performance as an anticorrosion epoxy resin coating tends to be lowered.

[Component (B): Epoxy adduct-modified aromatic amine curing agent]

  The epoxy resin-based paint for anticorrosion of the present embodiment includes (B) an epoxy adduct-modified aromatic amine-based curing agent, so that the amount of free amine in the paint is reduced and the adsorption of acid components by free amine is suppressed. Therefore, the corrosion resistance (chemical resistance) of the anticorrosion epoxy resin coating can be dramatically improved.

  The (B) epoxy adduct-modified aromatic amine curing agent contained in the anticorrosion epoxy resin coating of the present embodiment is a reaction between an epoxy compound such as bisphenol A type epoxy resin and an aromatic amine curing agent. Obtainable. The epoxy compound used for adduct modification is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, 2-ethylhexyl glycidyl ether, alkyl (C12-13) glycidyl ether, butyl glycidyl ether, allyl glycidyl ether. , Phenyl glycidyl ether, cresyl glycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and the like, and as an aromatic amine curing agent to be reacted with an epoxy compound Is not particularly limited, and examples thereof include metaphenyl range amine, diaminodiphenylmethane, diaminodiphenylsulfone, and modified products thereof. Among the above, a compound obtained by modifying diaminodiphenylmethane with a bisphenol A type epoxy resin is preferable.

  The amount of the epoxy compound used for adduct modification is preferably 20 to 45 parts by weight, more preferably 25 to 40 parts by weight with respect to 100 parts by weight of the aromatic amine curing agent.

  Although it does not specifically limit as content of (B) epoxy adduct modification | denaturation amine type hardening | curing agent in the epoxy resin-type coating material for anticorrosion, Preferably it is 10-30 mass%, More preferably, it is 15-25 mass%. (B) If the content of the epoxy adduct-modified amine-based curing agent is more than 30% by mass, the workability tends to be remarkably lowered with the increase in the viscosity of the epoxy resin coating for anticorrosion. From 10% by mass If the amount is too small, the anticorrosion property (chemical resistance) decreases, and the performance as an anticorrosion epoxy resin coating tends to decrease.

[(C) component: mesitylene resin and / or xylene resin]
The epoxy resin coating for corrosion protection according to the present embodiment includes (C) a mesitylene resin and / or a xylene resin, thereby making the coating hydrophobic and preventing or suppressing the penetration of the acid component to prevent corrosion (chemical resistance). ) Can be further improved.

  Here, the mesitylene resin is a resin obtained by an addition condensation reaction of mesitylene and formaldehyde, and the xylene resin is a resin obtained by an addition condensation reaction of xylene and formaldehyde. The physical properties of the mesitylene resin and / or xylene resin are not particularly limited, but the epoxy resin for corrosion protection has a viscosity of 30 to 100 mPa · s, an average molecular weight of 150 to 500, and a specific gravity of 1.0 to 1.1 affects the workability. From the viewpoint of adjusting the viscosity of the paint.

  Although it does not specifically limit as content of (C) mesitylene resin and / or xylene resin in the epoxy resin coating material for anticorrosion, Preferably it is 3-10 mass%, More preferably, it is 5-7 mass%. (C) If the content of the mesitylene resin and / or xylene resin is more than 10% by mass, the mechanical strength (physical properties) of the coating film tends to decrease, and if it is less than 3% by mass, the anticorrosion epoxy The resin-based paint is not sufficiently hydrophobized and the anticorrosion performance tends to decrease.

  The epoxy resin-based paint for anticorrosion of the present embodiment can be usually obtained by mixing (A) a main agent containing an epoxy resin and (B) a curing agent containing an epoxy adduct-modified amine curing agent. (C) The mesitylene resin and / or the xylene resin may be contained in the main agent or in the curing agent.

  Furthermore, the anticorrosive epoxy resin paint of the present embodiment includes a diluent for adjusting the viscosity, a pigment for coloring, a thixotropic agent, and a coupling within a range that does not impair the anticorrosion property (chemical resistance). You may contain other additives, such as an agent, surfactant, a filler, an antifoamer. Diluents include, for example, monofunctional reactive diluents such as 2-ethylhexyl glycidyl ether, alkyl (C12-13) glycidyl ether, butyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, and neopentyl. Polyfunctional reactive diluents such as glycol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, non-reactive diluents such as benzyl alcohol and dibutyl phthalate, etc .; Black, titanium oxide, etc .; as thixotropic agent, spherical silica, etc .; as coupling agent, silane coupling agent, etc .; as surfactant, nonion, cationic surfactant, etc .; as filler, calcium carbonate , Las flakes, natural or synthetic silica, barium sulfate and the like; As the antifoaming agent include known additives such as polybutadiene-based defoaming agent, be used those additives alone or in combination. Furthermore, the above-mentioned other additives may be contained in the main agent or in the curing agent.

  In this Embodiment, in order to ensure the fluidity | liquidity at the time of the low temperature of a hardening | curing agent, it is preferable to add 10-40 mass% of benzyl alcohol and / or dibutyl phthalate in a hardening | curing agent.

[How to prevent deterioration of water use structures]
The method for preventing deterioration of a water utilization structure according to the present embodiment includes a step of applying an anticorrosion epoxy resin coating to the inner surface of the water utilization structure.

  Examples of the irrigation structures include public sewers, bill pits, and the like that are composed of a sludge concentration tank, a sludge digestion tank, a sludge storage tank, and the like. In addition, the inner surface material of the irrigation structure is generally concrete, but examples of materials other than concrete include mortar, steel, FRP, various plastic materials, etc., in particular, concrete, mortar, etc. Is preferred.

  In the deterioration preventing method of the present embodiment, an anticorrosion epoxy resin coating is applied to the inner surface of the water conserving structure to form a coating film. At this time, it may be applied directly to the inner surface to form a coating film. In order to improve the adhesion to the object (underlying), after forming a primer layer, an anti-corrosion epoxy resin coating is applied. Also good. The primer to be used is selected in consideration of the adhesiveness and workability between the base and the anticorrosive epoxy resin paint. From the viewpoint of preventing deterioration of an object due to a pinhole, a luminescent agent-containing primer that can easily find a pinhole by irradiating an ultraviolet lamp or the like can be preferably used.

As the primer, for example, known primers such as epoxy resin (water), epoxy resin (solvent-free), urethane resin and the like can be used, and among them, epoxy resin (solvent-free) from the viewpoint of health and safety. ) Is preferred. Moreover, although the application quantity of a primer changes with the conditions of an application surface, it is preferable from a viewpoint of adhesiveness and cost that it is 0.1-0.5 kg / m < ² >.

The coating amount of the epoxy resin coating for anticorrosion varies depending on the required durability, the acid concentration conditions of sewage and wastewater, etc., but is preferably 0.5 to 2.0 kg / m ² , more preferably 0. .8 to 1.7 kg / m ² .

  Moreover, you may use together the epoxy resin-type coating material for anti-corrosion with another anti-corrosion coating material and auxiliary material by construction conditions. Specifically, in the case of improving the resistance to water pressure from the back of the target structure, the anticorrosion epoxy resin paint is applied after applying glass fiber and another anticorrosion paint having viscosity capable of impregnating the glass fiber. Or, in order to prevent damage or peeling due to displacement of the target structure, the anticorrosion epoxy resin paint may be applied after applying another flexible anticorrosion paint.

  Hereinafter, the anticorrosion epoxy resin paint of the present embodiment will be specifically described based on examples, but the present invention is not limited to these examples.

[Evaluation methods]
The corrosion resistance (chemical resistance) of the anticorrosion epoxy resin paint was evaluated by the following weight change rate and EPMA analysis.

(Method for preparing test samples)
Cured products of various anticorrosion epoxy resin paints having a diameter of 50 mm × thickness of about 5 mm and a weight of about 10 g were cured at 20 ° C. for 7 days to prepare test samples for weight change rate. A test sample whose weight change rate was measured was cut out, and a test sample for EPMA analysis was collected. For EPMA analysis, EPMA-1400 manufactured by Shimadzu Corporation was used, and scan analysis was performed at an acceleration voltage of 15 KV.

(Evaluation conditions: immersion solution and temperature conditions)
The immersion solutions used in the anticorrosion test were 10% sulfuric acid aqueous solution, 5% formic acid aqueous solution and 5% propionic acid aqueous solution, and the temperature of the aqueous solution was 20 ° C. and 40 ° C.

(Evaluation Method 1: Weight Change Rate)
After immersing the test sample in each immersion solution, collecting the sample from the aqueous solution after 7, 30 and 120 days, rinsing with running water, wiping off the water with a waste cloth, and immediately measuring the weight of the sample to determine the weight relative to the initial weight. The rate of change was measured. The number of samples was 3 for each condition, and the weight change rate was the average value.

(Evaluation method 2: EPMA analysis)
EPMA (Electrum) of test sample immersed in 10% sulfuric acid aqueous solution at 40 ° C. for 180 days
The permeability of sulfuric acid was measured by ron Probe Micro Analyzer analysis.

Example 1
(1) 70 parts by weight of bisphenol A type epoxy resin (AER250 manufactured by Asahi Kasei Chemicals Co., Ltd., the same shall apply hereinafter), 10 parts by weight of mesitylene resin (NIKANOL Y-51 manufactured by Fudou Co., Ltd.), 15 wt% of cresyl glycidyl ether The main component was a mixture of 4 parts by weight of spherical silica (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd., the same applies hereinafter) and 1 part by weight of titanium oxide.
(2) A mixture of 20 parts by weight of bisphenol A type epoxy resin, 60 parts by weight of diaminodiphenylmethane, 25 parts by weight of dibutyl phthalate, 5 parts by weight of phenylglycidyl ether, and 5 parts by weight of salicylic acid was used as a curing agent.
(3) 100 parts by weight of the main agent having the above composition and 50 parts by weight of the curing agent were mixed to produce an anticorrosion epoxy resin coating.

(Example 2)
(1) 70 parts by weight of bisphenol A type epoxy resin, 10 parts by weight of xylene resin (NICANOL-LLL manufactured by Fudo Co., Ltd.), 15 parts by weight of cresyl glycidyl ether, 4 parts by weight of spherical silica, 1 part by weight of titanium oxide The mixture was used as the main agent.
(2) A mixture of 20 parts by weight of a bisphenol A type epoxy resin, 60 parts by weight of diaminodiphenylmethane, 25 parts by weight of dibutyl phthalate, 5 parts by weight of phenylglycidyl ether, and 5 parts by weight of salicylic acid was used as a curing agent.
(3) 100 parts by weight of the main agent having the above composition and 50 parts by weight of the curing agent were mixed to produce an anticorrosion epoxy resin coating.

(Comparative Example 1)
(1) 70 parts by weight of bisphenol A type epoxy resin, 10 parts by weight of phenol-modified hydrocarbon low polymer (TRE200 manufactured by Toho Chemical Industry Co., Ltd.), 15 parts by weight of cresyl glycidyl ether, 4 parts by weight of spherical silica, titanium oxide 1 A mixture of parts by weight was used as the main agent.
(2) A mixture of 20 parts by weight of bisphenol A type epoxy resin, 60 parts by weight of diaminodiphenylmethane, 25 parts by weight of dibutyl phthalate, 5 parts by weight of phenylglycidyl ether, and 5 parts by weight of salicylic acid was used as a curing agent.
(3) 100 parts by weight of the main agent having the above composition and 50 parts by weight of the curing agent were mixed to produce an anticorrosion epoxy resin coating.

(Comparative Example 2)
(1) A mixture of 70 parts by weight of bisphenol A type epoxy resin, 10 parts by weight of mesitylene resin, 15 parts by weight of cresyl glycidyl ether, 4 parts by weight of spherical silica, and 1 part by weight of titanium oxide was used as a main agent.
(2) Mixing 100 parts by weight of the main component having the above composition with 50 parts by weight of Mannich-modified metaxylenediamine curing agent (DS-4, manufactured by BRT Japan KK), an epoxy resin coating for anticorrosion Manufactured.

(Comparative Example 3)
(1) A mixture of 75 parts by weight of a bisphenol A type epoxy resin, 20 parts by weight of cresyl glycidyl ether, 4 parts by weight of spherical silica, and 1 part by weight of titanium oxide was used as a main agent.
(2) 100 parts by weight of the main agent having the above composition and 50 parts by weight of a modified aliphatic amine-based curing agent (ADEKA HARDNER EH220 manufactured by ADEKA Co., Ltd.) were mixed to produce an epoxy resin coating for anticorrosion.

  The measurement results of the rate of weight change and the results of EPMA analysis are shown in Tables 1 to 4.

As is clear from the results of Tables 1 to 4, the anticorrosion epoxy resin paints of the present embodiment (Examples 1 and 2) have a small weight change rate after being immersed in each immersion solution, and in EPMA analysis. The sulfur penetration depth was also small. From the above results, it was found that the anticorrosion epoxy resin coating of the present embodiment is extremely excellent in anticorrosion (chemical resistance).
On the other hand, the paint of Comparative Example 1 does not contain (C) a methicylene resin and / or a xylene resin, and the paint of Comparative Example 2 contains (B) an epoxy adduct-modified aromatic amine curing agent. Therefore, the weight change rate of the test sample was large and the corrosion resistance was poor. In particular, the coating material of Comparative Example 3 did not contain both (C) a methicylene resin and / or xylene resin and (B) an epoxy adduct-modified aromatic amine-based curing agent, and the corrosion resistance was significantly inferior.

The epoxy resin-type paint for corrosion prevention of the present invention has extremely excellent anticorrosion properties, and can be used as an anticorrosion paint for sewer related facilities as well as an anticorrosion paint for building pits that require organic acid resistance. Has industrial applicability.

Claims (3)

(A) an epoxy resin;
(B) an epoxy adduct-modified aromatic amine curing agent;
(C) a mesitylene resin and / or a xylene resin;
Epoxy resin paint for corrosion protection.   The epoxy resin paint for corrosion protection according to claim 1, comprising 20 to 60% by mass of the component (A), 10 to 30% by mass of the component (B), and 3 to 10% by mass of the component (C).   A method for preventing deterioration of an irrigation structure, comprising a step of applying the anticorrosion epoxy resin paint according to claim 1 or 2 to an inner surface of the irrigation structure.