JPS6134751B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an epoxy-based curable coating composition having excellent oil resistance and corrosion resistance. Traditionally, epoxy resin compositions with excellent corrosion resistance, such as bituminous epoxy resin compositions, have excellent water resistance,
It has characteristics such as salt water resistance and oil resistance, and is widely used in heavy corrosion protection fields such as ship ballast tanks, crude oil tanks, and steel water pipes. In particular, ships' ballast tanks are in a severely corrosive environment as crude oil and seawater enter alternately, and the heavy-duty anticorrosion materials required are highly resistant to oil and seawater, and are relatively inexpensive as they do not cover external parts. These black bituminous epoxy resins are used because they can be supplied in large quantities. There are two types of bituminous materials: coal tar-based ones and petroleum-based ones, and generally coal tar-based ones are mainly used. This is a typical petroleum-based product. This is because straight asphalt, blown asphalt, etc. generally have poor compatibility with epoxy resins and amine curing agents, making it difficult to put them to practical use as they are. However, coal tar-based coating compositions are thought to pose a risk to the health of those who apply them, and for environmental hygiene reasons, cheaper and better alternative coating compositions to coal tar-based coatings are widely sought after. It has been demanded. On the other hand, especially when these coating compositions are used for coating ballast tanks, crude oil tanks, etc., they are required to have excellent oil resistance since they come into contact with mineral oils. That is, the amount of the coating composition extracted into the mineral oil upon contact with the mineral oil after application and curing must be extremely small. Asphalt-based epoxy compositions do not have sufficient oil resistance, as shown in Comparative Examples below. The present invention relates to a novel epoxy coating composition that overcomes these drawbacks and has excellent corrosion resistance and oil resistance. The present invention uses 100 parts by weight of an epoxy resin having at least two epoxy groups in the molecule, heavy oil with a boiling point of 150°C or higher obtained by thermal decomposition of petroleum hydrocarbons, or steam decomposition at 350 to 400°C. Petroleum based pitch heat treated at any temperature within the range
The object of the present invention is to provide a curable coating composition having excellent oil resistance and containing 40 to 200 parts by weight and an appropriate amount of an epoxy resin curing agent. The present invention will be explained in more detail below. The petroleum hydrocarbons referred to in the present invention include crude oil, light oil,
Things such as kerosene and naphtha, which usually cost 600~
A heavy oil obtained as a by-product during the production of lower olefins such as ethylene and propylene by thermal decomposition or steam decomposition at 1000°C, with a boiling point of 150°C or higher, used as the raw material oil for the composition of the present invention. be done. In the present invention, this raw material oil is heat-treated at 350 to 400°C, preferably 370 to 390°C.
The viscosity of the reaction product can be adjusted by distilling the reaction product under reduced pressure to remove light components or by cutting off light oil components, and the miscibility with the epoxy resin and workability can be adjusted. As shown in the Comparative Examples below, if the reaction temperature is lower than 350°C, the composition will have poor compatibility with the epoxy resin, and the practical strength of the composition will be low, and the oil resistance will also be extremely poor. Moreover, if the reaction temperature exceeds 400°C, the compatibility with the epoxy resin will deteriorate. It is not exactly clear why excellent properties are exhibited only after heat treatment within a predetermined temperature range. However, it is thought that the thermal polymerization, thermal decomposition, and other complex reactions of heavy oil due to heat treatment do not proceed sufficiently at temperatures below 350°C, and a substance that satisfies the desired properties is not produced. In this case, it is considered that the reaction to increase the molecular weight progresses too much and a substance with the desired properties is not produced. In the case of coal tar, although it has the disadvantages mentioned above, it has relatively good oil resistance due to the presence of polycyclic aromatics (benzene insoluble matter) or phenols, which are contained in large amounts in coal tar. It is generally believed that asphalt-based compositions, on the other hand, have poor compatibility with epoxy resins and poor oil resistance because their main components are aliphatic hydrocarbons. Contrary to these general considerations, the heat-treated feedstock oil referred to in the present invention usually has a benzene insoluble content of about 10% or less and a very small amount of polycyclic aromatics, but it is an epoxy resin with excellent oil resistance. composition. It is quite surprising that an excellent epoxy composition can only be obtained by heat-treating the raw material oil at a predetermined temperature in the present invention. The heat treatment is accomplished by supplying the raw material oil to a conventional reactor, such as a stirring vessel or a tubular reactor, and heating and stirring it. The reaction time is not particularly limited, but is usually 10 minutes to 10 hours, preferably 20 minutes to 3 hours. The reaction pressure is also not particularly limited, but it is usually carried out at atmospheric pressure or a pressurized pressure of 0 to 50 kg/cm ² G. The reaction can be carried out batchwise or continuously. It is of course possible to preheat it before feeding it to the reactor. Next, in the present invention, at least an epoxy group is added in the molecule.

An epoxy resin having two or more of the following formula is used as one component. The bonding portion of these resins with the epoxy group is composed of aromatic, heterocyclic, aliphatic, cycloaliphatic, or derivatives thereof, and is usually the same as that used in coal tar-based and epoxy resins. Typical examples include glycidyl epoxy resins such as glycidyl ether type, glycidyl ester type, and glycidyl amine type, aliphatic epoxy resins such as epoxidized olefin type, epoxidized vegetable oil, and cycloaliphatic epoxy resin. It is representative. Specific examples of these include epi-bis type epoxy resin produced from epichlorohydrin and bisphenol A, polypropylene glycol diglycidyl ether, and pentaerythritol polyglycidyl ether. The amount of the epoxy resin and the heat-treated heavy oil used is 40 to 200 parts by weight of the heat-treated heavy oil, preferably 50 to 150 parts by weight, per 100 parts by weight of the epoxy resin.
Parts by weight. Furthermore, the composition of the present invention contains an epoxy resin curing agent as an essential component. As the curing agent, those commonly used as curing agents for tar epoxy resins are used. These include aliphatic amines, aromatic amines, amine adducts, acid anhydrides, polyamide resins, etc., such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-aminoethylpiperazine, imidazoles, piperidine, diethylaminopropylamine, phthalic anhydride, etc. Although the amount of these curing agents is not particularly limited, it is usually used in an amount of 10 to 150 parts by weight per 100 parts by weight of the epoxy resin. The composition of the present invention contains the above-mentioned three components as essential components, and among these, the epoxy resin and the curing agent are used as a mixture during coating. The heat-treated heavy oil can be mixed in advance with either or both of the epoxy resin and the curing agent. In addition to these essential components, the composition of the present invention includes fillers used in ordinary epoxy resin compositions,
A diluent, a flexibility imparting agent, etc. may be included. The present invention will be explained in more detail with reference to Examples below. Example 1 A heavy residual oil with a boiling point of 150°C or higher, obtained as a by-product when steam cracking naphtha to produce olefin, was stored in a stirring vessel, and at 370°C it was heated to 8 kg/kg.
The mixture was reacted for 5 hours under a pressure of cm ² to obtain a heat-treated product.
A cured product was obtained by mixing 115 parts of this heat-treated product, 100 parts of an epoxy resin (Epicote 828 manufactured by Ciel Chemical Co., Ltd.), and 15 parts of triethylenetetramine. The toluene extraction loss of the cured product was 7.2 wt%. In addition, the toluene extraction loss, which is a measure of the oil resistance of the cured product, is
This was done in accordance with JIS K-6911-5.32. That is, the mixture immediately after mixing was molded into a diameter of 50 mm and a thickness of 3 mm, left at room temperature for 7 days, and further molded at a temperature of 50°C for 1 time.
It was cured for one day and used as a specimen. The specimen was placed in toluene at room temperature, taken out after 7 days, dried at 120°C for 2 hours, and the weight loss extracted by toluene was measured. Measurements were made in the same manner in the following Examples and Comparative Examples. From these results, it is clear that the epoxy resin composition of the present invention has extremely excellent oil resistance. Example 2 The same heavy residual oil as in Example 1 was used as a raw material at 390°C.
Reacted for 1 hour under a pressure of 10Kg/cm ² at
A heat-treated product was obtained. Using this, a cured product was obtained by the same formulation as in Example 1. The toluene extraction loss of the cured product was 4.5 wt%. Similar to Example 1, this result shows that the epoxy resin composition of the present invention has excellent oil resistance. Example 3 The same heavy oil as in Example 1 was placed in a stirring container,
Heat treated at 390°C, 9Kg/cm ² for 4 hours. 100 parts of the obtained treated product, 100 parts of epoxy resin (Epomiku R-139 manufactured by Mitsui Petrochemical Epoxy Co., Ltd.), and 12 parts of diethylenetriamine as a hardening agent were added, and the mixture was cured in the same manner as in the example, and the oil resistance was measured. The amount of toluene extracted was 7.0wt%. Comparative Example 1 115 parts of straight asphalt, 100 parts of the epoxy resin of Example 1, and 15 parts of triethylenetetramine were mixed, but a sufficiently cured product was not obtained even after 7 days, and the weight loss after extraction with toluene reached 65 wt%. Comparative Example 2 Using the same heavy residual oil as in Example 1 as a raw material, heating at 340℃
The mixture was reacted for 1 hour under a pressure of 5 kg/cm ² to obtain a heat-treated product. Using this, a cured product was obtained by the same formulation as in Example 1. The toluene extraction loss of the cured product was 42.8 wt%. Comparative Example 3 The same heavy residual oil as in Example 1 was used as a raw material at 420°C.
A heat-treated product was obtained by reacting for 1 hour under a pressure of 10 kg/cm ² . Using this, a cured product was obtained by the same formulation as in Example 1. The toluene extraction loss of the cured product was 42.8 wt%. Comparative Example 3 The same heavy residual oil as in Example 1 was used as a raw material at 420°C.
The mixture was reacted for 1 hour under a pressure of 10 kg/cm ³ to obtain a heat-treated product. Using this, a cured product was obtained by the same formulation as in Example 1. The toluene extraction loss of the cured product was 39.7 wt%. The results of Comparative Example 2 and Comparative Example 3 indicate that excellent results are not obtained when the specific heat treatment referred to in the present invention is not performed.

Claims (1)

[Claims] 1. 100 parts by weight of an epoxy resin having at least two or more epoxy groups in the molecule, a boiling point of 150 obtained by thermal decomposition or steam decomposition of petroleum hydrocarbons.
Petroleum-based pitch 40-200 made by heat-treating heavy oil above ℃ at any temperature within the range of 350 to 400℃
parts by weight, and an appropriate amount of an epoxy resin curing agent. 2. Claim No. 2, characterized in that the epoxy resin curing agent is diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-aminoethylpiperazine, imidazoles, piperidine, diethylaminopropylamine, phthalic anhydride, etc. The oil-resistant cured coating composition according to item 1. 3 Adding the epoxy resin curing agent to the epoxy resin
The oil-resistant cured coating composition according to claim 1 or 2, which contains 10 to 150 parts by weight per 100 parts by weight.