JPS6241984B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heavy-duty anti-corrosion paint containing a corrosion-resistant ceramic composition, and particularly to a heavy-duty anti-corrosion paint with high heat resistance and salt water resistance. In this specification, heavy-duty anticorrosion paint refers to a paint used for the purpose of corrosion protection in places with severe corrosive environments caused by acids, alkalis, heat, salt, and the like. BACKGROUND ART Anticorrosive paints that are applied to metal surfaces have been known for the purpose of preventing corrosion and rust. For example, epoxy paints or unsaturated polyester paints using mica-like glass flakes or iron oxide are known to be effective; It has the disadvantage that it is greatly affected by the surface condition of the surface treatment at the time of preparation, and its adhesion to rusted surfaces is particularly poor. Therefore, the inventor filed a patent application in 1983.
-227538 (Japanese Patent Application Laid-Open No. 59-122559),
It is relatively unaffected by the surface condition of the object to be coated, that is, it maintains strong adhesion with simple surface treatment, and it also contains pigments with good compatibility, improving anticorrosion performance, heat resistance, and abrasion resistance. The following heavy-duty anti-corrosion ceramic paint was proposed: Namely, this heat-resistant heavy-duty anti-corrosion ceramic paint consists of: a) 25-55% by weight of silicon carbide (SiC), 30-50 parts by weight, stabilized zirconium oxide (ZrO).
10-30 parts by weight, aluminum oxide (Al ₂ O ₃ ) 20-40 parts by weight, silicon nitride (Si ₃ N ₄ ) 5-20 parts by weight, mica-like glass flakes 5-20 parts by weight, mica-like iron powder 5-20 parts by weight 20 parts by weight, and mica-like aluminum hydroxide (Al(OH) ₃ )
Ceramic component consisting of 5-20 parts by weight, b 10-50% by weight of polymerized linseed oil, c 10-25% by weight of urethanized modified linseed oil, and d 5-20% by weight of styrene-butadiene rubber or chlorinated rubber. It contains. However, even this heavy-duty anti-corrosion ceramic paint provides satisfactory corrosion protection for metals located in places where they are simultaneously exposed to heat loads and the corrosive action of seawater or corrosive gas atmospheres, such as steam pipes where seawater is splashed or attached. cannot be achieved (see comparative example below). Therefore, as a result of intensive research into heavy-duty anti-corrosion ceramic paints that can achieve sufficient anti-corrosion effects even under such harsh conditions, the inventors found that the following paints, which further added boron nitride and silicone resin, satisfied this requirement. In other words, the heat-resistant heavy corrosion-resistant ceramic paint of the present invention is: a 25-55% by weight silicon carbide (SiC) 30-50 parts by weight stabilized zirconium oxide (ZrO)
10 to 30 parts by weight, aluminum oxide (Al ₂ O ₃ ) 20 to 40 parts by weight, boron nitride (Si ₃ N ₄ ) 5 to 20 parts by weight, boron nitride (BN) 5 to 20 parts by weight, mica-like glass flakes 5 ~20 parts by weight, mica-like iron powder 5-20 parts by weight, and mica-like aluminum hydroxide (Al
(OH) ₃ ) Ceramic component consisting of 5-20 parts by weight, b 10-50% by weight of polymerized linseed oil, c 10-25% by weight of urethanized modified linseed oil, d 5-20% by weight of styrene-butadiene rubber. Alternatively, it is characterized by containing chlorinated rubber and 5 to 20% by weight of silicone resin. The total content of each compound constituting the ceramic component as a corrosion resistance imparting material is the sum of all components (a+b
+c+d+e) 25-55% by weight depending on the application
may be changed within the range of The individual compounds constituting the ceramic component and their advantageous amounts used are as described above. The critical significance regarding the amount of each compound to be used is detailed below. In the present invention, boron nitride, which is used as one of the ceramic components, works to improve the salt water resistance of the paint film, but if it is less than 5 parts by weight (1.25% by weight based on the entire paint), this substance may be present in the paint film. Because it is not possible to obtain a layered parallel arrangement of ceramic components, the effectiveness is low, and even if it exceeds 20 parts by weight (11% by weight of the entire paint), there is no additional effectiveness, and in relation to the amount of other ceramic components, 20 Parts by weight (based on the entire paint)
11% by weight) or less. Silicon carbide and stabilized zirconium oxide work to improve the heat resistance, acid resistance, and alkali resistance of the paint film. If the amount of stabilized zirconium oxide is less than 10 parts by weight (2.5% by weight based on the total paint), the heat resistance, acid resistance, and alkali resistance of the coating film will decrease, causing deterioration of the coating film. Even if silicon carbide exceeds 50 parts by weight and stabilized zirconium oxide exceeds 30 parts by weight, there is no additional effect, and in relation to the amounts of other ceramic components, the amounts are 50 parts by weight or less and 30 parts by weight or less, respectively. is advantageous. Aluminum oxide works to improve the hardness of the paint film, and if the amount of this compound is less than 20 parts by weight (5% by weight based on the entire paint), the hardness of the paint film will drop significantly and the wear resistance will deteriorate. decreases. Even if more than 40 parts by weight is used, there is no additional effect, and in view of the amount of other ceramic components, it is advantageous to use less than 40 parts by weight. Silicon nitride has the property of increasing the tightness of the paint film, and mica-like glass flakes, mica-like iron powder, and mica-like aluminum hydroxide have the ability to prevent corrosive components from penetrating into the paint film due to their shapes. . Silicon nitride is 5
5 parts by weight of mica-like (nearly flaky or mica-like) glass flakes, 5 parts by weight of mica-like iron powder, or 5 parts by weight of mica-like aluminum hydroxide (each 1.25% by weight of the entire paint) If this is not achieved, it is not possible to obtain a layered parallel arrangement of these materials in the coating that is effective in inhibiting the penetration of corrosive components. Although each of these components can be used in an amount exceeding 20 parts by weight, it is advantageous to use less than 20 parts by weight each since there is no additional effect thereby and in relation to the amounts of other ceramic components. The polymerized linseed oil as film former b is advantageously in the range from 10 to 50% by weight, based on the total coating material.
If this is less than 10% by weight, the coating thickness will become too thin and the above-mentioned amount of ceramic component cannot be incorporated into the coating. If it exceeds 50% by weight, the amount of oil and fat layer will be too large, making it impossible to obtain sufficient coating film hardness, and as a result, only a coating film will be obtained that has poor abrasion resistance and is prone to cracking. Urethane-modified linseed oil c is commonly used in the paint industry and is advantageously used in an amount of 10 to 25% by weight based on the total paint. If it is less than 10% by weight, the adhesion to the rusted surface of the object to be coated will decrease. It is possible to exceed 25% by weight, but for economic reasons and 25% by weight.
There is no point in using a higher amount as there is no additional effect based on it. Component d, styrene-butadiene rubber (SBR) or chlorinated rubber as a binder is common in the paint industry and its usage should not exceed 20% by weight of the total paint. 20
If it exceeds % by weight, the surface of the coating film becomes sticky, the coating film hardness is insufficient, and it cannot withstand practical use. If it is less than 5% by weight, the inherent properties of the binder will deteriorate and the coating film will likely deteriorate. The silicone resin used as component e is component d.
It functions to prevent the paint from aging and becoming easily peeled off under heat load, and it is ineffective if it is less than 5% by weight of the entire paint, and there is no additional effect even if it is used in more than 20% by weight. do not have. The heavy corrosion-resistant ceramic paint of the present invention may contain a diluting solvent, a drying accelerating coating, a pigment, and other additives. Pigments include common anti-rust pigments and/or moisture-resistant pigments, such as aluminum hydroxide and calcium carbonate. Aromatic hydrocarbons such as mineral turpentine, mineral spirits, etc. are suitable as diluting solvents. Such a solvent not only dilutes the paint but also dissolves the d component. From the viewpoint of the viscosity and fluidity of the paint, the amount used is preferably 5 to 20% by weight based on the total paint. As the drying accelerator, inorganic desiccants used in the field of paints are advantageous, and lead naphthenate, cobalt naphthenate, or a mixture of both are particularly preferred. Among these, it is appropriate to use a combination of lead naphthenate, which is effective for drying the inside of the coating, and cobalt naphthenate, which is effective for drying the outer surface of the coating. The amount of desiccant used is
It is effective if the amount is 0.5% by weight or more of the entire paint, but since there is no change in the catalytic effect even if it is 10% by weight or more, it is meaningless to use more than 10% by weight. Next, the present invention will be explained in more detail using the following examples and comparative examples. Example 1 The following ingredients are mixed and homogenized: Polymerized linseed oil 10% by weight Urethane-modified linseed oil (30% by weight modified linseed oil with urethane) 15% by weight Styrene-butadiene rubber 6% by weight Silicone resin 8% by weight % Mineral turpentine 10.5% by weight Drying accelerator (lead naphthenate and cobalt 1:
1 mixture) 0.5% by weight Ceramics: 50% by weight Silicon carbide 30.0 parts by weight Stabilized zirconium oxide 7.5 〃 Aluminum oxide 35.0 〃 Silicon nitride 12.5 〃 Boron nitride 12.5 〃 Mica-like glass flakes 10.0 〃 Mica-like iron powder 5.0 〃 Mica-like hydroxide Aluminum 12.5 〃 Apply the obtained paint to a thickness of approximately 0.7 mm using a brush on a steel pipe that has been rust-removed with sandpaper. This was subjected to a salt water resistance test under heating as follows. After drying at 20°C for 2 hours, warm water at 75-85°C is passed through and room temperature seawater is sprayed onto the coating surface every 24 hours. The degree of rust occurrence is evaluated on a 100-percent basis by visual observation after taking a photograph of the coating surface. The results are shown in Table 1. Example 2 The following components are mixed and homogenized: Polymerized linseed oil 15% by weight Urethane-modified linseed oil (30% by weight urethane modified linseed oil) 18% by weight Chlorinated rubber 7% by weight Silicone resin 10% by weight Mineral turpentine 10.4% by weight Drying accelerator (1 of lead naphthenate and cobalt:
1 mixture) 0.6% by weight Ceramics: 39% by weight Silicon carbide 20 parts by weight Stabilized zirconium oxide 12.5 parts by weight Aluminum oxide 12.5 parts by weight Silicon nitride 5 parts by weight Boron nitride 25 parts by weight Mica-like glass flakes 5 parts by weight Mica-like iron powder 10 Part by weight Mica-like aluminum hydroxide 7.5 parts by weight This paint was also subjected to a salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Example 3 The following ingredients are mixed and homogenized: Polymerized linseed oil 20% by weight Urethane-modified linseed oil (30% by weight urethane modified linseed oil) 12% by weight Styrene-butadiene rubber 9% by weight Silicone resin 6% by weight Mineral turpentine 8.4% by weight Drying accelerator (lead naphthenate and cobalt 1:
1 mixture) 0.6% by weight Ceramics: 44% by weight Silicon carbide 35.0 parts by weight Stabilized zirconium oxide 10 parts by weight Aluminum oxide 15 parts by weight Silicon nitride 5 parts by weight Boron nitride 5 parts by weight Mica-like glass flakes 7.5 parts by weight Mica-like iron powder 12.5 Parts by weight Mica-like aluminum hydroxide 10 parts by weight This paint was also subjected to a salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Example 4 The following ingredients are mixed and homogenized: Polymerized linseed oil 32% by weight Urethane-modified linseed oil (30% by weight modified linseed oil with urethane) 10% by weight Styrene-butadiene rubber 5% by weight Silicone resin 5% by weight % Mineral turpentine 10.4% by weight Drying accelerator (lead naphthenate and cobalt 1:
1 mixture) 0.6% by weight Ceramics: 42% by weight Silicon carbide 25 parts by weight Stabilized zirconium oxide 15 parts by weight Aluminum oxide 12.5 parts by weight Silicon nitride 7.5 parts by weight Boron nitride 7.5 parts by weight Mica-like glass flakes 12.5 parts by weight Mica-like iron powder 7.5 Parts by weight Mica-like aluminum hydroxide 5 parts by weight This paint was also subjected to the salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Example 5 The following ingredients are mixed and homogenized: Polymerized linseed oil 13% by weight Urethane-modified linseed oil (30% by weight modified linseed oil with urethane) 11% by weight Chlorinated rubber 6% by weight Silicone resin 18% by weight Minerals Turpentine 10.5% by weight Drying accelerator (1 of lead naphthenate and cobalt:
1 mixture) 0.5% by weight Ceramics: 41% by weight Silicon carbide 20.0 parts by weight Stabilized zirconium oxide 7.5 parts by weight Aluminum oxide 28.0 parts by weight Silicon nitride 10.0 parts by weight Boron nitride 15.0 parts by weight Mica-like glass flakes 10.0 parts by weight Mica-like iron powder 10.0 Part by weight Mica-like aluminum hydroxide 10.0 parts by weight This paint was also subjected to the salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 This comparative example corresponds to the paint disclosed in Japanese Patent Application No. 57-227538. Mix and homogenize the following ingredients: Polymerized linseed oil 10% by weight Urethane-modified linseed oil (30% by weight modified linseed oil with urethane) 20% by weight Styrene-butadiene rubber 8% by weight Mineral turpentine 10.5% by weight Drying acceleration Agent (1 with lead naphthenate and cobalt:
1 mixture) 0.5% by weight Ceramics: 51% by weight Silicon carbide 47.5 parts by weight Stabilized zirconium oxide 7.5 parts by weight Aluminum oxide 37.5 parts by weight Silicon nitride 7.5 parts by weight Mica-like glass flakes 10.0 parts by weight Mica-like iron powder 5.0 parts by weight Mica-like water Aluminum oxide 12.5 parts by weight This paint was also subjected to the salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2 This comparative example relates to a composition of the coating material of the present invention excluding the silicone resin. Mix and homogenize the following ingredients: Polymerized linseed oil 10% by weight Urethane-modified linseed oil (30% by weight urethane modified linseed oil) 15% by weight Styrene-butadiene rubber 8% by weight Mineral turpentine 10.5% by weight Drying accelerator (1 with lead naphthenate and cobalt:
1 mixture) 0.5% by weight Ceramics: 56% by weight Silicon carbide 47.5 parts by weight Stabilized zirconium oxide 7.5 parts by weight Aluminum oxide 37.5 parts by weight Silicon nitride 7.5 parts by weight Boron nitride 12.5 parts by weight Mica-like glass flakes 10.0 parts by weight Mica-like iron powder 5.0 Part by weight Mica-like aluminum hydroxide 12.5 parts by weight This paint was also subjected to the salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 3 This comparative example relates to a composition of the paint of the present invention excluding boron nitride. Mix and homogenize the following ingredients: Polymerized linseed oil 10% by weight Urethane-modified linseed oil (30% by weight modified linseed oil with urethane) 15% by weight Styrene-butadiene rubber 8% by weight Silicone resin 10% by weight Mineral turpentine 10.5% by weight drying accelerator (lead naphthenate and cobalt 1:
1 mixture) 0.5% by weight Ceramics: 46% by weight Silicon carbide 35.0 parts by weight Stabilized zirconium oxide 7.5 parts by weight Aluminum oxide 37.5 parts by weight Silicon nitride 7.5 parts by weight Mica-like glass flakes 10.0 parts by weight Mica-like iron powder 5.0 parts by weight Mica-like water Aluminum oxide 12.5 parts by weight This paint was also subjected to the salt water resistance test in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 4 Commercially available heat-resistant pyrosine (manufacturer: Dainippon Paint Co., Ltd.
KK), a salt water resistance test was conducted in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 5 A salt water resistance test was conducted in the same manner as in Example 1 on the commercially available anticorrosive paint Sabirock (manufacturer: Relief Engineering KK). The results are shown in Table 1.

[Table] As can be seen from the table above, in the case of the paint of the present invention,
Even after 40 days, there is no or almost no rust, and in the case of commercially available paints, there is no rust after 10 days or 40 days.
In the case of the present invention, the degree of rusting reaches 50% after 90 to 100 days. Further, by comparing the paints of Comparative Examples 1 to 3 with the paints of the present invention in Table 1, it can be seen that rusting is significantly suppressed by mixing boron nitride and silicone resin.

Claims (1)

[Claims] 1 a 25-55% by weight of silicon carbide (SiC) 30-50 parts by weight of stabilized zirconium oxide (ZrO)
10 to 30 parts by weight Aluminum oxide (Al ₂ O ₃ ) 20 to 40 parts by weight Silicon nitride (Si ₃ N ₄ ) 5 to 20 parts by weight Boron nitride (BN) 5 to 20 parts by weight Mica-like glass flakes 5 to 20 parts by weight Mica-like iron powder 5 to 20 parts by weight and mica-like aluminum hydroxide (Al ₂ (OH) ₃ )
Ceramic component consisting of 5-20 parts by weight b: 10-50% by weight of polymerized linseed oil, c: 10-25% by weight of urethanized modified linseed oil, d: 5-20% by weight of styrene-butadiene rubber or chlorinated rubber, and e. A heavy-duty anti-corrosion ceramic paint characterized by containing 5 to 20% by weight of silicone resin.