JPH05214291A - Coating resin composition and its production - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in heat resistance, corrosion resistance, adhesiveness, etc., by compatibly mixing an aromatic polyimide with an aromatic polysulfone to give a resin composition and mixing this composition with an epoxy resin and a specified compound. CONSTITUTION:90-30wt.% aromatic polyimide is compatibly mixed with 10-70wt.% aromatic polysulfone to give a resin composition, which is mixed with 10-50wt.% epoxy resin and then with an imidazole compound (e.g. benzimidazole) in an amount of 5-30wt.% based on the weight of the epoxy resin to give the title composition. It is obtained preferably by subjecting an aromatic diamine of formula II (wherein Ar is a divalent aromatic group) and an aromatic tetracarboxylic acid dianhydride of formula III [wherein R is a tetravalent group selected from monocyclic and (non)condensed polycyclic aromatic groups] to ultrasonic waves to react in an organic solvent in the presence of an aromatic polysulfone having repeating units of formula I to give an aromatic polyimide precursor of formula IV, and mixing the precursor with an epoxy resin and an imidazole compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coating for an aromatic polyimide, an aromatic polysulfone, an epoxy resin and a curing agent thereof, which are excellent in heat resistance, corrosion resistance, steam resistance, adhesiveness and mechanical strength. (Hereinafter, referred to as coating resin composition) and its manufacturing method.

[0002]

2. Description of the Related Art In plants such as petroleum refining and petrochemicals, various anticorrosive measures are taken in various places. For example, it is well known that in an atmospheric distillation column of crude oil, etc., corrosion due to the contained salt, sulfur, or organic acid occurs, and as a countermeasure against this, injection of ammonia, amine, etc. is performed. There is. However, this measure cannot completely protect the carbon steel used for the tower top and the like from corrosion.

There is a case where a countermeasure such as spray lining titanium is applied to such a portion, but it is not always preferable because the cost is high and the spray coating of titanium is porous.

Further, conventionally, measures have been taken to coat such portions with an organic material to prevent corrosion, and phenolic resins, unsaturated polyesters, and epoxy resins are often used as the organic materials. However, since these polymers have a low heat resistant temperature, even if glass fibers, inorganic powders (silica, alumina, carbon black, etc.) and other suitable fillers having a high heat resistant temperature are mixed, the temperature of the plant at 200 ° C. It cannot be used under driving environment.

A fluorine-based polymer having excellent heat resistance, such as Teflon, may be used in place of such a resin, but such a polymer is expensive and inferior in adhesiveness and workability. Therefore, it is applied only in special cases.

On the other hand, among the high-performance polymers that have been rapidly developed in recent years, many have been proposed that have heat resistance close to 300 ° C. and are relatively inexpensive.
Therefore, the above-mentioned problems of heat resistance and price can be solved by using an organic material mainly composed of such a high-performance polymer.

From such high-performance polymers, when an aromatic polymer containing a heterocycle is selected as a polymer having a function of withstanding corrosion, a coating material that can withstand practical use in a high temperature corrosive environment. It is possible that Therefore, when the physical properties of various aromatic polymers were evaluated, it was found that aromatic polyimide was promising.

By the way, the aromatic polyimide has heat resistance,
Although it has excellent chemical resistance, it decomposes imide and amide bonds under high temperature and acidic conditions, causing a decrease in molecular weight and deterioration in performance.Therefore, in order to compensate for this performance, an aromatic fragrance with an ether bond having high temperature water resistance. It is preferred to mix the group polysulfone. However, since it is extremely difficult to mix the aromatic polyimide and the aromatic polysulfone, both of them are uniformly finely divided by the ultrasonic irradiation method described in Japanese Patent Application No. 2-61516 previously proposed by the present inventors. It is preferable to disperse and mix.

However, even if a resin composition obtained by uniformly mixing an aromatic polyimide and an aromatic polysulfone by an ultrasonic irradiation method is used as a coating material as it is, the adhesive strength of the aromatic polysulfone is low, so that it functions sufficiently. do not do. In order to compensate for this, it is conceivable to mix an epoxy resin which has been widely used as an adhesive from the past, in particular, an aromatic epoxy resin having high heat resistance or Tg which is an index thereof.

For the epoxy resin, a method of adding a curing agent such as imidazole to form a bond and polymerize the epoxy resin is generally adopted. On the other hand, it has been reported that imidazole serves as a catalyst for causing a ring-closing reaction from a polyamic acid which is a precursor of polyimide at a low temperature (Japanese Patent Laid-Open No. 59-2).
No. 23725). Further, it is known that imidazole itself has an anticorrosion function, and by adding it, the performance as a corrosion resistant coating material can be further enhanced.

In consideration of the above points, the present invention takes heat resistance,
It is an object of the present invention to provide a coating resin composition having excellent corrosion resistance, adhesiveness, mechanical strength and the like, and a method for producing the same.

[0012]

Means and Actions for Solving the Problems The present inventors have
As a result of extensive studies to achieve the above object, in an organic solvent, aromatic polyamic acid which is a precursor of aromatic polyimide, and aromatic polysulfone in a state of being intimately mixed, an epoxy resin and its By mixing an imidazole-based compound that is a curing agent, it was found that heat resistance, corrosion resistance, adhesiveness, mechanical strength, etc. are excellent, and therefore a resin composition excellent as a coating material can be obtained.
The present invention has been completed.

That is, the coating resin composition of the present invention is a mixture containing an aromatic polyimide, an aromatic polysulfone, an epoxy resin and a curing agent thereof, wherein the aromatic polysulfone is about 10 to 70% by weight and the aromatic polyimide is about 10% by weight. About 30 to 90% by weight of an intimately mixed resin composition, about 10 to 50% by weight of an epoxy resin, preferably about 20 to 3%.
0 wt%, and further, an imidazole compound as a curing agent, preferably an imidazole compound having an aromatic nucleus,
It is characterized in that about 5 to 30 wt%, preferably about 5 to 15 wt% is added to the weight of the epoxy resin.

Further, the method for producing the coating resin composition of the present invention is a method of producing an epoxy resin in a state where an aromatic polyamic acid which is a precursor of an aromatic polyimide and an aromatic polysulfone are uniformly dispersed in an organic solvent. And an imidazole compound as a curing agent, preferably an imidazole compound having an aromatic nucleus.

Further, the method for producing the coating resin composition of the present invention is the same as that of Chemical formula 5 in the presence of an aromatic polysulfone having a repeating unit represented by the general formula (I) of Chemical formula 4 in an organic solvent. A precursor of an aromatic polyimide obtained by reacting an aromatic diamine represented by the formula (II) with an aromatic tetracarboxylic dianhydride represented by the general formula (III) of Chemical formula 6 while irradiating ultrasonic waves. The aromatic polyamic acid represented by the general formula (IV) of the chemical formula 7 is mixed with an epoxy resin and an imidazole compound as a curing agent thereof, preferably an imidazole compound having an aromatic nucleus. ..

[0016]

[Chemical 5]

[0017]

[Chemical 6]

[0018]

[Chemical 7]

[0019]

[Chemical 8]

The aromatic polysulfone represented by the general formula (I) used in the present invention is a polyarylene compound in which an arylene unit is randomly or regularly arranged together with an ether and a sulfone bond and has an intrinsic viscosity (0.5 g / dl,
Dimethylformamide, 30 ° C) is about 0.1-4.0,
Those of about 0.3 to 2.0 are preferable. Specifically, there may be mentioned those represented by the general formula (V) of Chemical formula 8 and further specific examples of the repeating unit are shown in Chemical formula 9.

[0021]

[Chemical 9]

[0022]

[Chemical 10]

Further, as the aromatic diamine represented by the general formula (II), which can be used in a range that does not impair various good physical properties of the aromatic polyimide used in the present invention, metaphenylenediamine and orthophenylenediamine , Aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone,
4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, bis [4-
(3-Aminophenoxy) phenyl] methane, bis [4
-(4-aminophenoxy) phenyl] methane, 1,1
-Bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane , 2,2-bis [4- (4-
Aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane,
2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane , 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 4,4 ′ -Bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis- [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) Phenyl] ketone, bis- [4- (3-aminophenoxy) phenyl] sulfone, bis- [4- (4-aminophenoxy) phenyl] sulfone, bis- [4-
(3-Aminophenoxy) phenyl] ether, bis-
[4- (4-aminophenoxy) phenyl] ether,
1,4-bis- [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis- [4- (3-aminophenoxy) benzoyl] benzene and the like can be mentioned.

Further, in the present invention, the aromatic tetracarboxylic acid dianhydride represented by the general formula (III) to be reacted with the aromatic diamine as described above is pyromellitic dianhydride, 3,3 '. , 4,4'-Benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3'-Benzophenonetetracarboxylic dianhydride, 3,3', 4,4 '
-Biphenyltetracarboxylic dianhydride, 2,2 ',
3,3'-biphenyltetracarboxylic dianhydride, 2,
2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride , Bis (3,4-dicarboxyphenyl) methane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1, 2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-
Benzenetetracarboxylic dianhydride, 3,4,9,10
-Perylene tetracarboxylic dianhydride, 2,3,6
7, -anthracene tetracarboxylic dianhydride, 1,
2,7,8, -phenanthrene tetracarboxylic acid dianhydride and the like can be mentioned.

As the epoxy resin used in the present invention, resorcinol, hydroquinone, bisphenol A, 4,4'-dihydroxybenzophenone, bis (4
-Hydroxyphenyl) -1,1-ethane, bis (4-
Hydroxyphenyl) -1,1-isobutane, bis (4
-Hydroxyphenyl) -2,2-butane, bis (2-
Dihydroxyphenyl) methane, phloroglucinol,
Examples thereof include glycidyl polyether obtained from polyhydric phenol such as bis (4-hydroxyphenyl) sulfone and epihalohydrin such as epichlorohydrin.

As a curing agent for such epoxy resin, amine-terminated polyamide, mercaptan, boron trifluoride, monoethylamine, and aromatic amines such as metaphenylenediamine, 4,4'-methylenediamine,
p-aminophenyl sulfone, benzyl dimethyl diamine, hexahydrophthalic anhydride, phthalic anhydride, pyromellitic anhydride, maleic anhydride, trimellitic anhydride, benzophenonetetracarboxylic dianhydride as an acid anhydride , Imidazole compounds and the like can be used.

However, in the present invention, as will be described later, since it also functions as a catalyst in the cyclization reaction of aromatic polyamic acid to aromatic polyimide, and further functions as a corrosion inhibitor after the film formation, An imidazole compound, especially an imidazole compound having an aromatic nucleus is used. As the imidazole compound, imidazoles represented by the general formula (VI) of chemical formula 10 and / or the general formula (VII) of chemical formula 11 are preferably used.

[0028]

[Chemical 11]

[0029]

[Chemical 12]

As a typical example thereof, N-cyanoethyl-
2-ethyl-4-methyl-imidazole, N-cyanoethyl-2-methylimidazole, N-cyanoethyl-2
-Phenylimidazole, 2-phenyl-4-methyl-
5-hydroxymethylimidazole, 2-phenyl-
4,5-dihydroxymethyl imidazole, imidazole, 2-methyl imidazole, 2-ethyl-4-methyl imidazole, 4-methyl imidazole, 2-undecyl imidazole, 2-phenyl-4-methyl imidazole, N-methyl imidazole, 2 -Phenylimidazole, 5-methylimidazole, N-phenylimidazole, 2-benzylimidazole, N-benzylimidazole, N-benzyl-2-methylimidazole, benzimidazole, 4,5,6,7-tetrachlorobenzimidazole, 5 -Methylbenzimidazole, 2-methylbenzimidazole, 6-benzylbenzimidazole and the like can be mentioned, but the invention is not necessarily limited thereto. These imidazoles may be used alone or in combination of two or more.

The above aromatic polysulfones, aromatic polyimides, epoxy resins and curing agents therefor, aromatic polyamic acids which are the precursors of the aromatic polyimides, aromatic diamines and aromatic tetracarboxylic acids which are the starting materials for the polyamic acids. As the organic solvent that dissolves any of the acid dianhydrides, amide-based solvents, ether-based solvents, phenol-based solvents and the like are used, and specifically, N, N-dimethylformamide, N, N-dimethylmethoxyacetamide. , N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether,
1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethyl sulfoxide,
Examples thereof include dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, phenol, m-cresol, p-cresol, o-cresol, anisole, p-chlorophenol, and hexafluoroisopropyl alcohol. These organic solvents may be used alone or in combination with
It is also possible to use a mixture of two or more species.

The coating resin composition of the present invention is a mixture of an epoxy resin and a curing agent thereof in a state in which an aromatic polyimide and an aromatic polysulfone are intimately mixed. In this coating resin composition,
By only applying the organic solvent solution on the metal surface, not only can it be used at a higher temperature than a conventional coating material using a general-purpose resin, but a film that is difficult to dissolve in various organic solvents is formed.

At this time, the aromatic polyimide 30-90w
10% to 50% by weight, preferably 20% to 30% by weight of an epoxy resin, based on the weight of a mixture of 10% by weight of aromatic polysulfone and 10% to 70% by weight of aromatic polysulfone. 5 to 30 wt% compound, preferably 5 to 15 w
The reason for mixing t% is to obtain the above-mentioned effect effectively. That is, when the mixing ratio of the aromatic polyimide, the aromatic polysulfone, the epoxy resin, and the imidazole compound does not satisfy the above, a film having high-temperature corrosion resistance cannot be formed on the metal surface, and the film is deteriorated by a corrosion test. , Peeling and decomposition easily occur.

The epoxy resin in the coating resin composition of the present invention not only has the function of improving the adhesion to the metal surface, but also has the function of maintaining the state in which the aromatic polyimide and the aromatic polysulfone are uniformly dispersed. Eggplant At the same time, the imidazole compound as a curing agent for the epoxy resin, particularly the imidazole compound having an aromatic nucleus, also acts as a catalyst for the cyclization reaction from an aromatic polyamic acid to an aromatic polyimide, as will be described later. It also acts as an anticorrosive. However, the excessive addition of the imidazole compound may impair the film-forming property of the coating resin composition of the present invention, so the above-mentioned addition amount is suitable.

In the method for producing the coating resin composition of the present invention, the polyamic acid, which is a precursor of the aromatic polyimide, and the aromatic polysulfone are intimately mixed with each other in the above-mentioned organic solvent (for example, by a scanning electron microscope, the diameter is about The epoxy resin and its curing agent are added while the island-shaped aromatic polysulfone of 10 μm or less is mixed until it is uniformly dispersed.

That is, the aromatic polysulfone having the repeating unit of the above general formula (I) and the aromatic polyamic acid of the general formula (IV) which is a precursor of the aromatic polyimide are
Dissolve the solution in an organic solvent and add the solution from about -30 ° C to about 80 ° C.
C., preferably about -20.degree. C. to about 30.degree. About 10 to 50 wt%, preferably about 20 to 30 wt% of the epoxy resin is added to the weight of the aromatic polysulfone and the aromatic polyamic acid, and the epoxy resin is added for about 30 minutes to about 2
Mixing operation is performed within the above temperature range for 4 hours, and an imidazole compound that is a curing agent for the epoxy resin, preferably an imidazole compound having an aromatic nucleus, is added to the epoxy resin in an amount of about 5 to 30 wt%, preferably About 5
15 wt% may be added and mixed in the above temperature range for about 10 minutes to about 3 hours.

At this time, if the temperature is lower than about -30 ° C, the melted matter may be solidified, and if the temperature exceeds about 80 ° C, the crosslinking reaction of the epoxy resin is promoted by heat and a curing agent, resulting in a rapid increase in viscosity. Occurs, making application difficult.

The resin solution obtained by the above is, for example,
A uniform resin composition containing a repeating unit can be obtained by applying the composition to a metal plate and then heating the coating as it is for about 1 to 24 hours at about 100 to 300 ° C, preferably about 120 to 200 ° C. The high temperature treatment at this time accelerates the formation of the aromatic polyimide represented by the general formula (VIII) shown in Chemical formula 12 by the ring closure of the aromatic polyamic acid and the crosslinking reaction of the blended epoxy resin with the curing agent, thereby three-dimensionally The main purpose is to form a high molecular weight polymer.

[0039]

[Chemical 13]

At this time, the polar portion of the aromatic polyamic acid or aromatic polyimide also serves as a curing agent for the epoxy resin. Further, of the imidazole compounds, the imidazole compound having an aromatic nucleus also has a catalytic function particularly in the ring-closing reaction from an aromatic polyamic acid to an aromatic polyimide.

As described above, according to the production method of the present invention, the epoxy resin and the curing thereof are prepared by intimately mixing the aromatic polyamic acid and the aromatic polysulfone, which are precursors of the aromatic polyimide, in the organic solvent. By mixing the imidazole compound as an agent, phase separation between the aromatic polyimide and the aromatic polysulfone is suppressed, and the epoxy resin is crosslinked to provide a uniform coating resin composition. For example, as described above, for example, when the metal plate coated with the mixture solution is heated, along with the removal of the solvent, the aromatic polyamic acid is closed to form an aromatic polyimide, and
The epoxy resin in a state of being mixed with the aromatic polyimide and the aromatic polysulfone is cross-linked by the curing agent to have a high molecular weight and becomes a coating resin composition in which each polymer is uniformly mixed, and at the same time, a coating film by the composition. Is formed.

At this time, as described above, the epoxy resin contributes to the adhesion to the metal surface, contributes to maintain a uniform dispersion state of the aromatic polyimide and the aromatic polysulfone, and the imidazole compound , Exerts a catalytic function in the cyclization reaction of the epoxy resin curing agent and the aromatic polyamic acid to the aromatic polyimide.

Further, although the production method of the present invention can be carried out by the usual chemical blending method as described above, the aromatic polyamic acid which is a precursor of the aromatic polyimide is added in the presence of the above-mentioned aromatic polysulfone. Then, the aromatic diamine represented by the general formula (II) and the aromatic tetracarboxylic dianhydride represented by the general formula (III) are reacted with each other while being irradiated with ultrasonic waves to obtain an epoxy diamine. Also included are those in which a resin and a curing agent are mixed to obtain a coating resin composition.

That is, according to the method described in Japanese Patent Application No. 2-61516, first, an aromatic polysulfone and an aromatic diamine are dissolved in an organic solvent, and the temperature is about -30 ° C to about 1 ° C.
Hold at 00 ° C, preferably about -20 ° C to about 50 ° C,
Frequency about 20 KHz to 3 MHz, preferably about 30 to 5
Aromatic tetracarboxylic acid dianhydride is injected under irradiation of ultrasonic waves at 00 KHz and reacted for about 1 to 24 hours to produce aromatic polyamic acid in a state of being intimately mixed with aromatic polysulfone. It should be noted that ultrasonic waves can be continuously applied after the aromatic polysulfone and the aromatic diamine are dissolved in the organic solvent. If the frequency of ultrasonic waves is less than about 20 KHz, the molecules that are uniformly mixed may be destroyed, and if it exceeds about 3 MHz, the mixing effect is reduced.

Then, the epoxy resin and the curing agent are added thereto, and they are mixed at about -30 ° C to about 80 ° C, preferably about -20 ° C to about 30 ° C, as described above. This makes it possible to obtain a coating resin composition in which the aromatic polysulfone, the aromatic polyamic acid and the aromatic polyimide are more closely mixed.

The upper limit of the temperature condition before the addition of the epoxy resin can be set higher than the upper limit of the temperature condition after the addition of the epoxy resin without the above-mentioned inconvenience of the rapid viscosity increase due to the promotion of the crosslinking reaction of the epoxy resin. Because.

As described above, in the production method of the present invention, aromatic polyimide and aromatic polysulfone, which are said to be extremely difficult to be intimately mixed, are mixed with aromatic polyamide which is a precursor of the aromatic polyimide. Acid, or intimately mixed via an aromatic diamine and an aromatic tetracarboxylic dianhydride, which are raw materials of the aromatic polyamic acid,
In this state, by compounding the epoxy resin and the curing agent therefor, phase separation between the aromatic polyimide and the aromatic polysulfone is suppressed, and the crosslinking reaction of the epoxy resin provides a uniform coating resin composition.

[0048]

EXAMPLE A coating resin composition prepared as described below was subjected to a deterioration test in a high temperature region of 200 ° C. for several months as follows on the premise of simulating a corrosive environment inside a distillation column. ..

First, a coating resin composition was prepared by the usual chemical blending method and ultrasonic irradiation method so that the proportions shown in Table 1 were obtained. That is, in Examples 1 and 2, the epoxy resin was added to the resin composition of the aromatic polyamic acid and the aromatic polysulfone that were uniformly dispersed and mixed at 0 ° C. under N ₂ atmosphere for 30 minutes to 24 hours. stirring and adding a curing agent was prepared by stirring again (chemical blending method), in examples 3 6, 0 ° C., N ₂ atmosphere,
A coating resin composition was prepared in the same manner as in Example 1 and Example 2 except that the ultrasonic wave was irradiated in an ultrasonic reaction tank having a transmission capacity of 40 KHz (ultrasonic wave irradiation method). Further, for comparison, a coating resin composition was prepared under the same ultrasonic irradiation conditions as above with the component ratios shown in Table 2. Table 2 shows an example when no curing agent is present. Furthermore, for comparison, coating resins were prepared by the solution blending method with the respective component ratios shown in Table 3.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

In Tables 1 to 3, * 1: polyamic acid composed of BTDA (4,4'-benzophenone tetracarboxylic dianhydride) and ODA (4,4'-diaminodiphenyl ether), * 2: aromatic poly Ether sulfone (using a product name "5003P" manufactured by British ICI), * 3: product name "Epicoat 82" manufactured by Yuka Shell Epoxy Co., Ltd.
8 ″ is used * 4: means benzimidazole (using the trade name “IBMI-12” manufactured by Yuka Shell Epoxy Co., Ltd.).

Then, each coating resin composition shown in Tables 1 and 2 was applied to a piece of metal (carbon steel) [S50C (composition:
C; 0.52%, Si; 0.22%, Mn; 0.67
%, P; 0.018%, S; 0.009%, Cu;
14%, Cr; 0.15%, Ni; 0.006%), size: 50 × 50 × 3 mm], and then the pressure is reduced by a reduced-pressure heating dryer, and the temperature is gradually raised.
The sample was heat-treated at 3 ° C. for 3 hours and naturally cooled to room temperature under reduced pressure to obtain a sample having a coating film with a thickness of about 100 μm.

These samples were subjected to a corrosion test in the following manner by the corrosion tester shown in FIG. 1 to evaluate the corrosion resistance of each sample. In addition, this test apparatus has a feature that each corrosive gas of H ₂ S, NH ₃ , and HCl can be flowed alone or in a mixture in an air or nitrogen stream, and the gas concentration can be controlled in ppm order. In addition to being able to simulate the corrosive environment of various plants such as the inside of a distillation tower,
It is also possible to perform an accelerated deterioration test of the material in a high temperature region up to 0 ° C.

The above sample is made of titanium metal fittings (not shown)
And was suspended on a glass table (not shown) provided in the corrosion test chamber 1 of FIG. It should be noted that 6 to 8 samples can be hung on one table, and
One is provided. Next, the gas supply pump PN ₂ is operated in the corrosion test chamber 1 to flow N ₂ gas, the temperature of the humidification tank 2 is set to 90 ° C., and the inside of the chamber 1 is made into a humidified N ₂ gas atmosphere.

Then, the temperature of the gas mixing tank 3 is set to 69.4 ° C.
Gas supply pumps PH ₂ S, PHCl, P
By operating NH ₃ , H ₂ S, HCl, and NH ₃ (each gas concentration 200 ppm) were supplied to the mixing tank 3 and mixed, and then flowed into the corrosion test chamber 1. Three hours after starting to flow the corrosive gas consisting of this mixed gas, the temperature in the corrosion test chamber 1 was raised to 200 ° C. The total gas flow rate in the corrosion test chamber 1 (volume of exhaust gas exhausted through the exhaust gas cleaning tanks 41 and 42) was set to 200 liter / h.

In this state, the gas supply pumps PH ₂ S, P
The operation of HCl and PNH ₃ was continued during the test period (2 months). After the test, these pumps PH ₂ S, PHCl,
The operation of PNH ₃ was stopped and the temperature inside the corrosion test chamber 1 was set to 100.
It was lowered to ℃. Nitrogen was kept flowing directly into the corrosion test chamber 1 without passing through the humidification tank 2. The other parts were turned off and naturally cooled until the temperature inside the corrosion test chamber 1 reached room temperature.

Regarding the sample taken out from the corrosion test chamber 1,
In order to quantify the deterioration of the coating surface, a surface property evaluation tester [Model HEIDON-14 manufactured by Shinto Kagaku Co., Ltd.]
The scratch resistance according to D] was measured. In addition, this tester
Fix the sample on the measuring table, place the scratching needle on it, put a weight on the weight pan attached to the upper part of the scratching needle, and start the measurement operation so that the measuring table moves. Since the resistance value to the test (scratch) load is related to the hardness of the coating film, the adhesive strength, and the roughness of the metal surface, it is used as an index of the deterioration of both the coating material and the metal surface. .. The measurement conditions are shown in Table 4. The measurement results are shown in Tables 5 to 7 and FIGS. 2 to 6.

[0060]

[Table 4]

FIG. 2 shows Example 3 and FIG. 3 shows Comparative Example 6.
4, FIG. 4 shows the results of Comparative Example 8, FIG. 5 shows the results of Comparative Example 10, and FIG. 6 shows the results without coating described later. 2 to 6, the vertical axis represents the resistance value [scale: 400 (scale at a load of 200 g is 400)].
The horizontal axis represents time [scale: 10 sec. ],
(A) is the result before the corrosion test, and (B) is the result after the corrosion test.

As is apparent from FIGS. 2 to 6, periodic fluctuations of the waveform were observed on the coating surface after the corrosion test,
Deterioration of the coating film was confirmed. Further, there was a correlation between the amplitude of this periodic fluctuation (ΔF) and the deterioration of the coating film, and the smaller the ΔF, the less the deterioration of the coating film (coating resin composition).

Further, as is clear from FIGS.
A coating film (comparative example 10 in FIG. 5) formed by a three-component resin composition [aromatic polyamic acid / epoxy resin (including a curing agent)] and a three-component resin composition [aromatic polyether sulfone / aromatic polyimide / The coating film of the epoxy resin (including the curing agent) (Example 3 in FIG. 2) did not show deterioration of the film even after the test, so that there is no great difference in performance. However, considering that the former requires a high temperature close to 300 ° C. at the time of construction, while the latter requires a treatment at 200 ° C., it can be said that the three-component system of the present invention is superior.

[0064]

[Table 5]

[0065]

[Table 6]

[0066]

[Table 7]

From Tables 5 to 7, it can be read that the sample of Example 3 is the most excellent.

Further, in order to grasp the corrosion level of the metal (carbon steel) when the coating with the coating resin composition is not applied, the corrosion test of each sample of the above-mentioned Examples, Reference Examples and Comparative Examples is conducted. At this time, even carbon steel without coating was attached to a metal fitting made of titanium and hung on a glass table in the corrosion test chamber 1 of FIG. 1 to perform a corrosion test, and after one month, it was 2-3%. It was found that there was a weight loss and that it was significantly corroded. In addition, the deterioration of the surface of the carbon steel after the corrosion test was evaluated by a scratch resistance by a surface property evaluation tester [Model HEIDON-14D manufactured by Shinto Kagaku Co., Ltd.] as in the above Examples, Reference Examples and Comparative Examples. Was measured and quantified. The results are shown in FIG.

Further, a sample using a commercially available epoxy-based coating material as in Comparative Example 1 was also subjected to a corrosion test in the same manner, but the result was similar to that of the uncoated carbon steel and did not function at all. I found out.

The infrared absorption spectra of the sample of Example 3 before and after the above corrosion test were measured, and the results are shown in FIG. As is clear from FIG. 7, Example 3
The coating resin composition of, even after the corrosion test,
It can be seen that the characteristic peaks such as C = O and C-O remain, and the corrosion test does not change the quality.

[0071]

As described in detail above, according to the present invention,
It has been said that intimate mixing has been extremely difficult from the past,
Since intimate mixing of aromatic polysulfone and aromatic polyimide has been realized, if an epoxy resin is added to this intimate mixture together with a specific curing agent, a sufficient anticorrosion effect can be obtained with conventional coating materials. It is possible to provide a coating material that can be put to practical use even in a high temperature corrosive environment, which was not possible.

[Brief description of drawings]

FIG. 1 is a schematic view showing a corrosion test apparatus used in a corrosion test for demonstrating the effect of the present invention.

FIG. 2 Coating resin composition of the present invention (Example 3)
It is a figure which shows the surface property evaluation test result before and behind the corrosion test of the metal piece which coated with (A) is a result before a test and (B) is a result after a test.

FIG. 3 is a diagram showing a surface property evaluation test result before and after a corrosion test of a metal piece coated with a coating resin composition for comparison (Comparative Example 6).
(B) is the result after the test.

FIG. 4 is a diagram showing a surface property evaluation test result before and after a corrosion test of a metal piece coated with a coating resin composition for comparison (Comparative Example 8), in which (A) is before the test.
(B) is the result after the test.

FIG. 5 is a diagram showing a surface property evaluation test result before and after a corrosion test of a metal piece coated with a coating resin composition for comparison (Comparative Example 10).
(B) is the result after the test.

FIG. 6 is a diagram showing a surface property evaluation test result before and after a corrosion test of a metal piece without a coating, in which (A) is a result before the test and (B) is a result after the test.

FIG. 7: Coating resin composition of the present invention (Example 3)
The figure which shows the infrared absorption spectrum before and behind the corrosion test of the metal piece which coated (A) before the test, (B)
Is the spectrum after the test.

[Explanation of symbols]

1 Corrosion test chamber 2 Humidification tank 3 Gas mixing tank 4 ₁ , 4 ₂ Gas purification tank PN ₂ , PH ₂ S, PHCl, PNH ₃ gas supply pump

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Claims (3)

[Claims] 1. A resin composition in which 10 to 70 wt% of aromatic polysulfone is intimately mixed with 90 to 30 wt% of aromatic polyimide is mixed with 10 to 50 wt% of an epoxy resin, and an imidazole compound is further added to the weight of the epoxy resin. A coating resin composition obtained by mixing 5 to 30 wt% of the above. 2. A coating resin composition comprising mixing an epoxy resin and an imidazole compound as a curing agent in a state where an aromatic polyamic acid and an aromatic polysulfone are uniformly dispersed in an organic solvent. Manufacturing method. 3. In an organic solvent, a compound of the general formula: In the presence of an aromatic polysulfone having a repeating unit represented by the general formula: And an aromatic diamine represented by the general formula: A compound represented by the following general formula, which is a precursor of an aromatic polyimide obtained by reacting an aromatic tetracarboxylic dianhydride represented by A method for producing a coating resin composition, which comprises mixing an aromatic polyamic acid represented by: with an epoxy resin and an imidazole compound.