JPS622633B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an anticorrosion composition and an anticorrosion tape obtained by impregnating and coating a porous tape base material with the composition. The purpose of the present invention is to provide an anticorrosion composition that is effective in preventing corrosion. Various methods have been proposed for preventing corrosion of steel pipes or steel structures, including the use of petrolatum-based anticorrosion tape, plastic anticorrosion tape, antirust paint, and the like. However, these tapes or paints do not pose much of a problem when the surface of the steel pipe or steel structure to be applied is relatively low at 100℃ or less, but if the surface is kept at a temperature of 100℃ or higher continuously. However, it has the disadvantage that its anti-corrosion function is significantly reduced. For example, petrolatum-based anticorrosion tapes are exposed continuously to temperatures of 130°C or higher, making it difficult to maintain sufficient thickness as the petrolatum flows out from the tapes, and plastic tapes are generally made of polyethylene, polyvinyl chloride, etc. Because of this, it deforms when continuously exposed to temperatures of 100°C or higher, and has drawbacks such as the formation of voids in the overlapped portions. On the other hand, hardening type grease is known as having heat resistance and anti-corrosion properties, but it hardens completely when exposed to high temperatures continuously, and as a result, cracks and cracks may occur due to external impact. The disadvantage is that damage occurs. Therefore, an object of the present invention is to provide an anticorrosive composition that does not cause undesirable phenomena as an anticorrosive material, such as outflow, deformation, and hardening, even when continuously exposed to high temperatures of 100 to 150°C. The object of the present invention is to (A) 5 to 90% by weight of petrolatum purified so that the dropping point is 50°C or higher;
The essential components are (B) 5 to 90% by weight of a curable grease with a dropping point of 150°C or higher and (C) 5 to 70% by weight of a low molecular weight polymer with an average molecular weight of 100 to 10,000, and the consistency is 25%.
This is achieved by designing the temperature to be 30 to 500 (1/10 mm) at ℃. According to the composition of the present invention, petrolatum that does not lose its viscosity even at high temperatures, a curable grease that thickens at high temperatures, and a low molecular weight polymer that provides the viscosity and physical strength of the coating film are identified. Because it is formulated at a ratio of is obtained. The petrolatum used in the present invention has a dropping point of 50
It is preferable to use a product that has been purified to a temperature above 50°C and has few polar groups and double bonds.If the dropping point is below 50°C, it will have poor spreadability and it will be difficult to obtain a uniform film thickness, and it will deteriorate at high temperatures. It is undesirable because it is difficult to obtain a strong film, and it is difficult to obtain a strong film. Grease is generally composed of mineral oil and metal soap, and by adding a curing component such as a drying oil to this, a curing type grease that hardens at high temperatures can be obtained. However, the dropping point is 150
If the temperature is below 0.degree. C., it is undesirable because it tends to liquefy at high temperatures. In the present invention, inorganic metal soaps such as sodium, barium, and lithium are preferably used as the metal soap, but organic metal soaps may also be used in combination. In addition, as a low molecular weight polymer, an average molecular weight of 100
~10,000, preferably 1,000 to 5,000 is suitably used. As the low molecular weight polymer, low molecular weight polymers such as olefin type, vinyl type, diene type, etc., such as low molecular weight polyethylene, polypropylene, polybutene, polybutadiene, polypentadiene, etc. are preferably used. These petrolatum, curable greases, and low molecular weight polymers are used in a ratio of 5 to 90:5 to 90:5 to 70 (weight ratio), and these are skillfully used to provide a It is necessary that it is designed to have a consistency of 500 (1/10 mm), preferably 50-200 (1/10 mm). If petrolatum and low molecular weight polymers are less than 5% by weight, the proportion of curable grease becomes too large and may harden at high temperatures, which is undesirable. This is undesirable because dripping of the polymer occurs. Moreover, if the low molecular weight polymer is less than 70% by weight, the viscosity becomes too low, which is undesirable.
The blending ratio is preferably the same as or slightly lower than that of petrolatum. The proportions of petrolatum, curable grease, and low molecular weight polymers are as above, but the molecular weight, type and amount of these are carefully selected, and the
It is necessary to design it with a consistency of 30-500 (1/10 mm). If the consistency is less than 30, it is undesirable because it has poor spreadability and it is difficult to obtain a uniform film thickness, and if it is more than 500, it is undesirable because it will sag at room temperature and the required film thickness cannot be obtained. Appropriate amounts of known compounding agents such as oils, fillers, pigments, and rust preventive agents can be added to the anticorrosion composition constructed in this way, but even in that case, the consistency will be in the range of 30 to 500. It is important to design this way. Since the anticorrosive composition of the present invention is configured as described above, the surface of the steel pipe, etc. is exposed to high temperature when a high-temperature fluid of 100 to 150°C is transported during or after construction on a steel pipe or steel structure. Also, the coated anticorrosive composition layer does not flow out, deform, harden, etc., and maintains a good anticorrosive effect over a long period of time. Examples of the present invention will be shown below. The text middle part means the weight part. Example 1 20 parts of petrolatum with a dropping point of 123°C, 60 parts of hardening type grease with a dropping point of 150°C or higher, 20 parts of polybutadiene with an average molecular weight of 2800, and 3 parts of a rust inhibitor were mixed at room temperature,
An anticorrosive composition with a consistency of 120 (at 25°C) is obtained. In order to evaluate the properties of the composition, a sample was prepared by uniformly spreading it on an iron plate to a thickness of 1 mm, and the sample was placed vertically in a hot air circulation dryer at 150°C.
After putting it in for 24 hours and observing the hardening state of the paint film,
There was no change in thickness (no run-off), and it deformed by just pressing lightly with a fingertip.Furthermore, when salt water was continuously sprayed on this coating surface (for 500 hours) and the state of rust was observed, no rust was observed. I couldn't help it. In addition, when we conducted a similar test on a sample that had been continuously placed in the dryer mentioned above for 350 hours, we found that the coating film was
Although it was considerably harder than when it had been left in for 24 hours, it retained sufficient flexibility, and no cracks were observed. Examples 2 to 5 The formulations shown in Table 1 were mixed to prepare anticorrosive compositions, and accelerated tests were conducted in the same manner as in Example 1. The test results are shown in Table 2.

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【table】

Claims (1)

[Scope of Claims] 1 (A) 5-90% by weight of petrolatum refined to have a dropping point of 50°C or higher, (B) 5-90% by weight of a curable grease with a dropping point of 150°C or higher, ( C) Low molecular weight polymer with an average molecular weight of 100 to 10,000 5
~70% by weight, is an essential component, and the consistency is 30~500 at 25℃
(1/10mm).