JPH0564643B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an underwater curable epoxy resin composition, and more particularly to a composition that can effectively prevent corrosion and staining of underwater structures. [Conventional technology] Construction and construction of oil drilling or oil stockpile purging associated with recent offshore development, steel structures such as offshore plant ships, piers of huge bridges constructed on the ocean, underwater steel structures of offshore airports, etc. However, it is almost impossible to move these from the installation area for maintenance purposes. Therefore, problems such as anti-corrosion coating, cleaning, maintenance, etc. occur in the underwater part of these marine steel structures or in the splash zone, and the need for maintenance at sea has become a major issue. One possible means to solve this problem is to form a coating with excellent anticorrosion properties on the underwater parts and splash zone parts of these underwater structures using the same simple and easy means as on land. Conventionally known underwater coating compositions include epoxy resin-based compositions,
There are compositions in which a polyamide or polyamine is used as a hardening agent and a filler is added thereto. However, this known composition has weak adhesion and is easily washed away by waves during curing, and even if it does cure, the adhesiveness of the cured product is insufficient and long-term corrosion protection cannot be expected at all. It's something that doesn't exist. The present inventor focused on the above-mentioned drawbacks of conventional underwater coating compositions, and developed an underwater coating that can be easily coated underwater by the same operation as on land, and can form a coating with excellent adhesion and high corrosion resistance. We have been conducting intensive research to develop a composition for water treatment and, in turn, to develop a method that can effectively protect underwater structures using this composition. We have successfully developed a water-curable epoxy resin composition and have already applied for a patent. This composition is a composition comprising (a) a base resin obtained from an alcohol ester of polyhydric phenol carboxylic acid having adjacent hydroxyl groups and an epoxy resin, and (b) a curing agent for epoxy resin (hereinafter referred to as the earlier application). composition). In this prior application composition, by using an epoxy resin and at least one kind of alcohol ester of polyhydric phenol carboxylic acid having adjacent hydroxyl groups (hereinafter referred to as alcohol ester) as the base resin, the original advantages of the epoxy resin can be realized. In addition to maintaining the coating film performance and curability as they are, the cooperative action of the phosphoric acid compound and the epoxy resin provides extremely excellent adhesion in water. For this reason, when a composition consisting of (a) and (b) above is applied, it has extremely high adhesion, so it will not be washed away by waves etc. before curing, and will harden as it is, and the cured film will have high adhesion. Therefore, it firmly adheres to underwater structures. In addition, the cured coating film retains the original excellent properties of epoxy resin, so it has extremely excellent anti-corrosion properties and other properties.
In the end, all of these features collectively provide an extremely excellent anti-corrosion effect and effectively protect underwater structures. It should be noted that the fact that the adhesion of ester resins in water is significantly improved by using alcohol esters and epoxy resins together is a completely unknown fact, and the present inventors have been researching this for many years. This is a surprising new fact discovered for the first time as a result of research. [Problems to be Solved by the Invention] As the present inventor continued further research on the above-mentioned underwater curable composition, it was discovered that when the composition of the prior application further contains a specific metal powder, this metal powder and the above-mentioned It has been found that the anticorrosion performance can be further improved by a synergistic effect with the composition consisting of (a) and (b). That is, the problems to be solved by the present invention are to solve the problems of conventional compositions of this type, and to further improve the anticorrosion performance of the composition of the prior application, which was able to solve the problems of conventional compositions of this type. That's true. [Means for solving the problem] This problem can be solved by adding metal powder, which has a greater ionization tendency than iron, to the composition consisting of (a) and (b) used in the composition of the prior application. It is achieved by doing so. That is, the present invention provides (a) a base resin obtained from an alcohol ester of a polyhydric phenol carboxylic acid having adjacent hydroxyl groups and an epoxy resin, (b) a curing agent for the epoxy resin, and (c) a resin having a greater ionization tendency than iron. The present invention relates to an underwater curable epoxy resin composition characterized by containing a metal powder. [Structure and operation of the invention] In the present invention, by using a base resin obtained from an epoxy resin and an alcohol ester, the drawbacks of conventional compositions of this type can be overcome, and extremely excellent anticorrosion performance can be achieved. do. What should be noted in particular is that by using the base resin together with a metal powder that has a higher ionization tendency than iron, the synergistic effect of the two will further improve the anticorrosion performance. This will be explained in more detail as follows. That is, in the present invention,
By using a predetermined amount of epoxy resin, alcohol ester, and metal powder with a higher ionization tendency than iron, the cooperative action of these three will further enhance the originally excellent coating performance of the epoxy resin, and will allow it to withstand extremely large amounts of water. Demonstrates adhesion. For this reason, when the composition of the present invention is applied to underwater steel structures, the adhesive strength is extremely high, so it will not be washed away by waves etc. before hardening, and will harden as it is, and the hardened coating will have a high adhesive strength. Strongly adheres to underwater steel structures. In addition, the cured coating film has excellent properties that exceed those of epoxy resin, so it has extremely excellent anti-corrosion properties and other properties.In the end, all of these features combine to provide an extremely excellent anti-corrosion effect, allowing it to be used underwater. This effectively protects the structure. The base resin used in the present invention is obtained from an epoxy resin and an alcohol ester. The method for producing this base resin is as follows. First, to explain the blending ratio of both raw materials, epoxy resin and alcohol ester, the blending ratio of both is in principle such that the epoxy group remains, and usually the ratio of alcohol ester to 1 equivalent of epoxy group in the epoxy resin is such that the epoxy group remains. The blending ratio is 0.025 to 0.5 mole. In addition, an average of 0.05 mol or more per mol of the product obtained by heat treatment from both of these,
Preferably, the blending ratio is such that 0.1 mol or more of alcohol ester is reacted and contained, and more preferably the blending ratio is such that the epoxy equivalent of the product is 3000 or less. A base resin is produced by heat-treating both raw materials blended in the above-mentioned predetermined proportions in the presence or absence of a solvent and, if necessary, in the coexistence of a catalyst. The heating temperature at this time is usually about 100 to 200℃, preferably 130 to 200℃.
The temperature is about 165°C, and the heating time is usually about 1 to 100 hours, preferably about 7 to 65 hours. Catalysts that may be used as necessary include, for example, dimethylbenzylamine, methylbenzylmethylamine,
Triethylamine, triethanolamine, 2-
Tertiary amines such as dimethylamino-2-hydroxypropane, tetramethylammonium chloride,
Quaternary ammonium salts such as trimethylmonoethyl ammonium chloride and tetramethylammonium fluoride; quaternary phosphonium salts such as tetramethylphosphonium iodide, tetramethylphosphonium bromide, tetramethylphosphonium chloride, and trimethylmonoethylphosphonium chloride; Examples include amine hydrochloride. Typical examples of the solvent include cyclohexanone, methyl cellosolve, butyl cellosolve, cellosolve acetate, cellosolve, etc.
Used in an amount of 50% by weight. The epoxy resin used as a raw material for the base resin in the present invention has the following formula: (However, Z represents a hydrogen atom, a methyl group, or an ethyl group.) Typical examples include those having at least one substituted or unsubstituted glycidyl ether group in the molecule, such as the diglycidyl ether of bisphenol A. , diglycidyl ether of bisphenol F, phenol novolac epoxy resin, diglycidyl ether of alkylene oxide adducts of bisphenols, etc. can be used, and the epoxy equivalent is not particularly limited, but preferably the epoxy equivalent is 200 to 200. Something around 1000 is good. The alcohol ester used in the present invention, more specifically, the alcohol ester of polyhydric phenol carboxylic acid having adjacent hydroxyl groups in the molecule, is an ester of the above-mentioned multi-phenol carboxylic acid and alcohol, preferably the above-mentioned polyhydric phenol. It is an ester of carboxylic acid and polyhydric alcohol. The polyhydric phenol carboxylic acids having adjacent hydroxyl groups used here include those having one or more carboxyl groups, such as catechol-3-carboxylic acid, catechol-4-carboxylic acid (protocatekylic acid), gallic acid (3, 4,
5-trioxybenzoic acid), m-digallic acid, pyrogallol-4-carboxylic acid, pyrogallol-
Preferred examples include 4,6-dicarboxylic acid and tannic acid. It is essential to use a polyhydric phenolcarboxylic acid having adjacent water residues; polyhydric phenolcarboxylic acids having non-adjacent hydroxyl groups are not preferred because their adhesion in water decreases. The hydroxyl groups present in the polyhydric phenol carboxylic acid are mainly consumed in the reaction with the epoxy resin, and the carboxyl groups are necessary for the ester with the alcohol. Furthermore, although a monohydric alcohol can be used as the alcohol used to form the ester, a polyhydric alcohol having a dihydrity or more is preferable. Specific examples include aliphatic monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, diols such as ethylene glycol, propylene glycol, butyrel glycol, 1,6-hexanediol, glycerin, trimethylolpropane, etc. Examples include polyols having a valence of 4 or higher, such as triol, pentaerythritol, sorbitol, and glycose. The ester reaction between a polyhydric phenol carboxylic acid having adjacent hydroxyl groups and an alcohol can be carried out according to a conventional method. As a typical structure of the ester produced in this way, for example, the case of an ester of glycerin and protocatechuic acid is shown. The example is as follows. However, it is thought that other higher-order condensates are also included. As the curing agent used in the present invention, those that are generally poorly soluble in water and have the ability to replace water molecules can be used, such as aliphatic amines, aromatic amines, alicyclic amines, polyamides, Examples include amine-modified amides, ketemine, and the like. These curing agents can be used alone or in combination of two or more, and together with this underwater curing agent, a room temperature curing agent that is normally used in the atmosphere can also be used. Examples include group polyamines, polyamidoamines, amine-containing adducts, and separated adducts. The amount of these curing agents used is also sufficient as the amount used as a normal curing agent, and the active hydrogen equivalent of the amino group is usually about 0.5 to 2.5 equivalents per equivalent of the epoxy group. Next, as metal powders having a larger ionization tendency than iron used in the present invention, zinc powder, aluminum powder, magnesium powder, chromium powder, zirconium powder, alloy powders of these powders, and composites of the above metals plated or vapor-deposited are used. There is powder,
One or more of these may be used. Among these, particularly preferred are zinc powder and aluminum powder. The average particle size of the powder is 1~
A range of 300 μm is preferable; if it is less than 1 μm, the effect of improving underwater adhesion will not be sufficient;
If it exceeds m, the appearance of the coating film will deteriorate and is therefore unsuitable. The shape of the powder may be flat, spherical, acicular, etc., as the effect on improving underwater adhesion is the same, and any shape is acceptable. The amount of these metal powders added is 5 to 75% in the epoxy resin composition whose main components are base resin, curing agent, and metal powder.
It is added in a range of % by weight. If the amount is less than 5% by weight, there will be no sufficient effect on improving underwater adhesion, and if it is more than 75% by weight, the cohesive force of the composition and the adhesion to the steel base will decrease, so it is difficult to say that it is preferable. The metal powder may be mixed in advance into either or both of a blending system containing an epoxy resin as a main component, a blending system containing an underwater curing agent as a main component for curing an epoxy resin, or an epoxy resin. It may be added when mixing a compound system containing a resin as a main component and a compound system containing an underwater curing agent as a main component. In addition, in the present invention, a filler can be used in combination, and the use of this filler improves underwater workability by adjusting viscosity and specific gravity, prevents peeling of the coating film due to the influence of waves, and adjusts and makes the coating film uniform. It can be expected to have effects such as improvement in hardening, leveling, mechanical strength of the cured product, stress relaxation, etc. This filler may be mixed in advance with the base resin or with the curing agent, or the base resin, curing agent, and filler may be mixed at the same time. A wide variety of fillers are used at this time, such as calcium carbonate, talc, clay, beretonite, carbon black,
Common examples include white carbon, which is used in an amount of 1 to 300 parts by weight based on 100 parts by weight of the base resin and curing agent. Various other additives including other epoxy resins can be used in combination with the composition of the present invention, if necessary. Examples of additives in this case include diluents, solvents, coloring pigments, antirust pigments, etc. can be cited as a specific example. Among the curing agents for epoxy resins used in the present invention, curing agents whose main component is polyamide amine having an average of about 1.7 or more primary or secondary amino groups per molecule are particularly preferred. By using this hardening agent, the adhesion is further improved and the anticorrosion performance is improved. This polyamide amine is the first
or secondary amino groups per molecule, on average about
It has 1.7 or more, and has a first-class amino value of 80 to 400.
are used. Examples of this include linoleic acid, oleic acid, linoleic acid, elaidic acid,
Dimer acid obtained by polymerizing fatty acids having unsaturated bonds in the molecule, such as ricinoleic acid,
Examples include condensation reaction products of polymerized fatty acids such as trimer acids and polyamines, particularly aliphatic polyamines. The most typical polyamide amine is a condensation reaction product of linoleic acid, timer acid or trimer acid, and polyamine. Its structure is as follows when, for example, dimer acid of linoleic acid is used as a raw material. (In the formula, R and R' are residues of polyamine, and may be the same or different types.) When protecting an underwater structure using the composition of the present invention, the underwater part of the underwater structure or The composition of the present invention is applied to the splash area. In this case, the same methods as those used on land can be applied effectively, such as brush painting, roll painting,
Examples include spatula painting and machine painting. brush painting,
20 to 500 poise for roller application, spatula application
It is best to set it at around 500 to 2000 poise. [Effects of the Invention] In the present invention, an epoxy resin and an alcohol ester are used as the base resin, and a metal powder having a higher ionization tendency than iron is used in combination with the base resin, thereby achieving the excellent coating performance inherent to the epoxy resin. In addition to maintaining its curability, extremely excellent adhesion in water is developed due to the cooperative action of the alcohol ester, epoxy resin, and metal powder. For this reason, when the composition of the present invention is applied, the adhesive strength is extremely high, so waves etc. do not wash away before curing, and it hardens as it is, and the cured film has high adhesiveness, so it firmly adheres to underwater structures. . In addition, the cured coating film retains the original excellent properties of epoxy resin, so it has extremely excellent anti-corrosion properties and other properties.
In the end, all of these features collectively provide an extremely excellent anti-corrosion effect, effectively protecting underwater structures. [Example] The present invention will be specifically explained with reference to Examples below. However, in the following examples, parts indicate parts by weight. Example 1 20 parts of protocatechuic acid triester of glycerin (molecular weight 500), 100 parts of bisphenol A diglycidyl ether (epoxy equivalent 190), 60 parts of ethyl cellosolve, and 0.15 parts of dimethylbenzylamine as a catalyst were added while stirring. , 7 at 150℃
A base resin (1) was obtained by performing an intermediate reaction. 100 parts of the base resin, 40 parts of calcium carbonate, and 2 parts of colloidal silica were mixed at 50° C. in a stirring mixing pot to prepare an epoxy resin blended system. On the other hand, 100 parts of aromatic modified polyamine (amine value 270, aromatic: diaminodiphenylmethane), 300 parts of zinc powder (average particle size 50 μm) and 20 parts of xylene were mixed in a stirring mixing pot at 50°C, and a curing agent compounded system was prepared. And so. By setting the mixing ratio (weight ratio) of this curing agent blending system and the above-mentioned epoxy resin blending system to 1:1,
A two-component underwater curable epoxy resin composition was prepared.
Initial adhesion when this composition was applied to a steel plate with a rubber spatula to a dry film thickness of 300 μm,
Adhesion, fracture rate, and rust occurrence after curing were measured. The results are shown in Table 1 below. However, the steel plate used was one that had been immersed in 3% common salt for one day immediately after shot blasting. Example 2 150 parts of bisphenol A/diglycidyl ether (epoxy equivalent: 190), 50 parts of diglycidyl ether of bisphenol A/propylene oxide adduct (epoxy equivalent: 340), 50 parts of m-digallic acid ester of glycose, cellosolve acetate 100
and 0.5 parts of triethylamine as a catalyst,
The reaction was carried out at 150°C for 16 hours to obtain base resin (2). 100 parts of the base resin (2), 40 parts of calcium carbonate, and 2 parts of colloidal silica were mixed at 50° C. in a stirring mixing pot to prepare an epoxy resin blended system. On the other hand, the curing agent compounding system used was the same as the curing agent compounding system of Example 1, and the mixing ratio (weight ratio) of this curing agent compounding system and the above epoxy resin compounding system (2) was 1:1.
By doing so, a two-component underwater curable epoxy resin composition was prepared, and treated in the same manner as in Example 1. The results are shown in Table 1. Example 3 150 parts of bisphenol F diglycidyl ether (epoxy equivalent 240), 50 parts of birogallol-4-carboxylic acid diester of diethylene glycol,
Add 100 parts of cyclohexanone and 1 part of triethanolamine as a catalyst and heat at 135°C with stirring.
The reaction was continued for 12 hours to obtain a base resin (3). 100 parts of the base resin (3), 40 parts of calcium carbonate,
and 2 parts of colloidal silica were mixed in a stirring mixing pot at 50°C to prepare an epoxy resin blended system. On the other hand, the curing agent compounding system used was the same as in Example 1, and the mixing ratio (weight ratio) of this curing agent compounding system and epoxy resin compounding system was 1:1, resulting in two-component underwater curability. An epoxy resin composition was prepared and treated in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 100 parts of unmodified bisphenol A diglycidyl ether (epoxy equivalent: 190), calcium carbonate
40 parts of colloidal silica, 2 parts of colloidal silica, and 10 parts of xylene were mixed at 50°C in a stirring mixing pot to prepare an epoxy resin blend system. On the other hand, the same curing agent compounding system as in Example 1 was used as the curing agent compounding system, and this compounding system and the epoxy resin compounding system were mixed at a mixing ratio (weight ratio) of 1:
1 to obtain a two-component underwater curable epoxy resin composition, which was treated in the same manner as in Example 1.
The results are shown in Table 1. Comparative Example 2 100 parts of unmodified bisphenol A diglycidyl ether (epoxy equivalent: 190), calcium carbonate
40 parts of colloidal silica, 2 parts of colloidal silica, and 10 parts of xylene were mixed at 50°C in a stirring mixing pot to prepare an epoxy resin blend system. On the other hand, 100 parts of aliphatic modified polyamine (amine value: 270, aromatic: diaminodiphenylmethane), 100 parts of calcium carbonate, and 20 parts of xylene were mixed at 50° C. in a stirring mixing pot to prepare a curing agent compounded system. This blended system and the above-mentioned epoxy resin blended system were mixed at a mixing ratio (weight ratio) of 2:3 to obtain a two-component underwater curable epoxy resin composition, which was treated in the same manner as in Example 1. The results are shown in Table 1.

[Table] However, the measurement methods for each physical property in Table 1 are as follows. Steel plate: 9 x 100 x 100 mm dull steel plate Coating method: After the above steel plate was immersed for a predetermined period of time, the composition was applied with a rubber spatula and cured while the steel plate was immersed. Initial adhesion: Observe the workability (adhesion) when applying with a rubber spatula,
The following evaluation was followed. ○...Good (adheres just by applying it with a rubber spatula) △...Possible (adheres if you apply it with a rubber spatula two or three times) ×...Poor (does not adhere) Adhesion after curing: Paint sample dipped after 6 months was taken out into the atmosphere (23℃, 65%RH), and after one day, the coating film was cut with a cutter.
Glue the measurement dolly with adhesive,
Adhesion force was measured using an adhesion stator. Cohesive failure rate: Place a polyethylene film of uniform thickness on the measurement area, remove the part of the coating film that has cohesively failed with a magic stick,
The weight was measured and the cohesive failure rate was calculated using the following formula. Cohesive failure rate = m ₁ /m x 100 (%) where m is the entire measurement area and m ₁ is the part where cohesive failure occurred. Occurrence of rust: The surface was visually observed to determine the presence or absence of rust.

Claims (1)

[Scope of Claims] 1. (a) A base resin obtained from an alcohol ester of a polyhydric phenol carboxylic acid having adjacent hydroxyl groups and an epoxy resin, (b) A curing agent for the epoxy resin, and (c) A resin having an ionization tendency higher than that of iron. An underwater curable epoxy resin composition, characterized in that it contains a large metal powder. 2 The amount of metal powder in the epoxy resin composition is 5~
75% by weight of the underwater curable epoxy resin composition according to claim 1. 3. The underwater curable epoxy resin composition according to claim 1 or 2, wherein the metal powder is zinc powder or aluminum powder.