JP2919032B2 - Anti-seizure agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is an anti-seize agent which eliminates seizures and provides smooth attachment / detachment by applying to bolts and nuts used in a high temperature and high vacuum environment. It is about.

(Prior art) In recent years, mechanical technology has progressed remarkably, and machines have been used in more severe environments. For example, the equipment of fusion devices and various vacuum devices have been used under high temperature and high vacuum. It is used by being exposed to. Many bolts and nuts are used at the joints of the machine parts that make up them,
During assembly, disassembly and repair, seizure of bolts and nuts is a very important problem.

Looking at the conventional technology of using anti-seizure agents, measures have been taken to prevent seizure, rust, corrosion, galling, etc., from the viewpoint of labor saving and efficiency improvement of equipment maintenance.
Typical applications are used in turbines, internal combustion engines, valves in the petrochemical industry, and screws used in glass and steel related gas generating furnaces. In addition, various anti-seizure agents are used under high-temperature and extreme-pressure conditions, and various measures have been taken, but most of them relate to pastes that combine a basic base oil and additives. Was.

At present, mineral oil is used as the base oil for pastes in many anti-seizure agents on the market. Since these are intended for use in a high temperature and atmosphere, a large amount of gas is released in a high vacuum, and there is a problem in that the inside of the system is contaminated by deterioration loss. In terms of additives, powders such as graphite and molybdenum disulfide and soft metals such as copper, lead and aluminum are used. In this case, depending on the additive used, there is a disadvantage that the components change due to oxidative deterioration and the performance is remarkably reduced. In addition, in the case of a dried film, there is a problem in that the film is damaged due to the performance of the additive to be coated, causing a sudden decrease in performance and a large variation in performance.

Also, when considering paste-type anti-seizure agents used at high temperatures and high vacuums, base oils that generate less gas and are less likely to contaminate the vacuum system, and additives that are either air or vacuum It is important to select a material that is stable at high temperatures even in an atmosphere. Further, in order to exhibit an excellent anti-seizure agent by adhering to the coated surface, it is necessary to devise a base oil, additives and blending-in, etc.

(Problems to be Solved by the Invention) An object of the present invention is to provide an anti-seizure agent which exhibits excellent performance under high temperature and high vacuum in consideration of the above points.

(Means for Solving the Problems) The present invention relates to (a) an alkyl-substituted tetraphenyl ether (provided that the number of substituents is 1 to 4 and the number of carbon atoms of the substituent is 6 to 20)
And b) 20 to 70% by weight of boron nitride having an average particle size of 0.1 to 50 μm.

In the present invention, as the base oil, an alkyl-substituted tetraphenyl ether which generates a smaller amount of gas in a high vacuum and hardly contaminates the vacuum system than the mineral oil is used, and as an additive, boron nitride which is excellent in high-temperature stability is used. The anti-seizure agent was developed. As a result of examining the anti-seizure properties of various bolts and nuts in air and vacuum atmospheres using these materials, the anti-seizure agent of the present invention is superior to the anti-seizure agent on the market. It has been found that it has the property.

That is, the present invention has a small amount of generated gas, and shows excellent high-temperature stability, vacuum characteristics, and anti-seizure properties when the above additives are combined with a base oil that does not easily contaminate the inside of a vacuum system.
Based on the fact that it has been confirmed that it exhibits excellent performance in preventing seizure of bolts and nuts used under high vacuum.

The alkyl-substituted tetraphenyl ether used as a base oil in the present invention (the number of substituents is 1 to 4, and the number of carbon atoms of the substituent is 6 to 6)
20) has higher thermal stability compared to other lubricating oils and has less evaporation even at high temperatures. For example, in terms of evaporation, 8 ×
Under reduced pressure of 10 ^-6 torr and 150 ° C, the accumulated loss of refined mineral oil in 48 hours (compared to refined mineral oil (mineral oil with light boiling point removed by distillation for diffusion pump oil)) ( The sum of the loss due to evaporation and the loss due to thermal decomposition) is 98%,
Alkyl-substituted tetraphenyl ether has a very low evaporation of 10%.

In addition, from the viewpoint of the stability of molecular synthesis, the alkyl-substituted tetraphenyl ether generates a smaller amount of pyrolysis gas as compared with mineral oil.

Under the atmosphere, base oil decomposes or evaporates when exposed to high temperatures and diffuses into the atmosphere.However, in a vacuum, the decomposed substance adheres to the vacuum system and contaminates it, or stays in the exhaust system and exhaust capacity. Or decrease. By using an alkyl-substituted tetraphenyl ether as a base oil, it is possible to reduce evaporation and decomposition products and reduce contamination in a vacuum system.

Boron nitride as an additive is stable at high temperatures and has a higher bolt / bolt ratio than molybdenum disulfide and soft metals conventionally used.
Since it has extremely low reactivity with stainless steel, molybdenum, etc. used as nut material, there is no welding due to the reaction, and the material is not easily changed. This appears in anti-seizure properties, and the product of the present invention shows excellent performance.

As for the amount of the base oil, if it is too large, dripping will occur and performance in actual use will be reduced, and if it is too small, applicability will deteriorate and it will not be suitable for use.

Examples of the boron nitride include Denkaboronitride [produced by Denki Kagaku Kogyo Co., Ltd.] and SHOWN (trade name) UHP [produced by Showa Denko KK] boron nitride HP [produced by Kawasaki Steel Corporation]. The particle size of boron nitride is preferably in the range of 0.1 to 50 μm from the viewpoint of stability as a paste, and the amount is preferably 20 to 70% by weight.

The anti-seizure agent of the present invention can be produced according to a conventional method. For example, the anti-seizure agent of the present invention can be produced as follows.

That is, a predetermined amount of a base oil and a predetermined amount of an additive are added and stirred and mixed. The mixing device can be carried out using an ordinary mixer, for example, a double planetary mixer. The mixing temperature is usually performed at room temperature, but considering use under vacuum,
It is desirable to perform the degassing operation at a temperature of 70 to 100 ° C. at the same time. A mixing time of 1 to 3 hours is sufficient.

The obtained mixture is then subjected to a homogenous mixing treatment according to a conventional method. This homogenous mixing can be performed by, for example, a mycolloider, a homogenizer, or a roll treatment.
The homogenous mixing temperature and time are 60 to 120 ° C for 10 to 60 minutes.

After homogeneously mixing the base oil and the additives, the mixture is again mixed under reduced pressure of 1 to 10 torr for 1 hour by using the above-described mixing apparatus, and defoaming to obtain a desired anti-seizing agent. Thus, the combination of the above components provides an anti-seizure agent having excellent performance under high temperature and high vacuum, as exemplified in the later examples.

(Examples) Hereinafter, the anti-seizure agent according to the present invention is manufactured, and the anti-seizure property in both atmosphere and vacuum and using various bolts and nuts materials is examined. The details of the comparison test with the products (Comparative products 1 and 2) will be described. However, this example illustrates the present invention and does not limit the present invention.

Example 1 Alkyl-substituted tetraphenyl ether (however, carbon number 16
A mixture of 1 to 4 substituents consisting of 2 main components), 450 g of boron nitride added to 550 g, stirred and mixed at 70 ° C. for 2 hours, and then homogenized using a mycolloider After that, defoaming treatment was performed to obtain a desired anti-seizure agent.

This anti-seizure agent is evenly applied to the contact portion of the stainless steel bolt / nut washer and tightened at 130 kgf · cm. Thereafter, the torque at the time of loosening after being left for 48 hours at 460 ° C. and 10 ⁻⁶ torr was measured, and the anti-seizure property was determined. The results are shown in Table 1.

Conventional products include mineral oil as base oil and copper as additive (Comparative Product 1), mineral oil as base oil, and copper / additive as additive.
A product using lead, molybdenum disulfide, and graphite (comparative product 2) was selected. Table 1 shows the results of the same test as in Example 1 using these.

If it can be loosened with the same torque as the tightening torque, it means that seizure has not occurred. Therefore, if the loosening torque is almost equal to the tightening torque, it is a good anti-seizure agent. A large value of the loosening torque indicates that seizure has occurred.

As is clear from Table 1, the anti-seizure agent according to the present invention exhibits a constant anti-seizure property regardless of air or vacuum, and is superior to the conventional anti-seizure agent. It indicates that

(Effects of the Invention) According to the present invention, a base oil that has a small amount of generated gas and that does not easily contaminate the inside of a vacuum system is selected, and an additive that is stable at a high temperature in both air and vacuum atmospheres is selected. However, by blending in an appropriate amount, an anti-seizure agent exhibiting excellent performance under high temperature and high vacuum can be obtained. The alkyl-substituted tetraphenyl ether used in the present invention is apparently excellent in radiation resistance from its training, and is suitable for use in a radiation environment. In addition, the additive according to the present invention is white in contrast to the conventional additive which is black, and thus has less problems of contamination of the working environment.

In addition, those containing sulfides form sulfur oxides at high temperatures,
A black sulfide film adheres to the metal surface, but is not formed by the anti-seizure agent of the present invention.

Therefore, the anti-seizure agent of the present invention exhibits excellent performance as an anti-seizure agent for bolts and nuts such as flanges, valves, etc., at connecting parts of structures and machine parts used under high temperature and high vacuum. can do.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Soda 10-33, Ashihara-cho, Nishinomiya-shi, Hyogo Inside the Matsumura Petroleum Institute Co., Ltd. Inside the Petroleum Research Laboratory (72) Inventor Tamio Akada 10-33, Ashihara-cho, Nishinomiya-shi, Hyogo Pref. Matsumura Petroleum Research Institute Co., Ltd. (56) References JP-A-2-248496 (JP, A) JP-A-61-272291 (JP) , A) JP-A-62-277494 (JP, A) U.S. Pat. No. 3,294,682 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 105/18 C10M 125 / 26,103 / 00 C10N 30 : 08 C10N 20:06 C10N 40:00 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) an alkyl-substituted tetraphenyl ether (provided that the number of substituents is from 1 to 4 and the number of carbon atoms of the substituent is from 6 to
20) and (ii) 20 to 70% by weight of boron nitride having an average particle size of 0.1 to 50 µm.