JP2009007425A - Non-diffusibile fluorine grease composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorine grease composition with extremely less leaving and diffusion of a fluorine oil, i.e., a base oil from the inside of a grease component. <P>SOLUTION: The fluorine grease contains a fluorine oil, as a base oil and a thickener such as polytetrafluoroethylene (PTFE), and contains 0.1-10 wt.% of silicone oil such as dimethylsilicone oil and 0.1-5.0 wt.% of nitrogen-containing surfactant such as an amine-based or amide-based surfactant. As the silicone oil, the silicone oil having kinematic viscosity at 40°C of 1-500 mm<SP>2</SP>/s is preferable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a non-diffusible fluorine grease composition in which oil in a grease does not diffuse on the surface of a member.

  Lubricants are indispensable in various mechanical parts, and many lubricants are used in various parts. For example, a grease product is a semi-solid oil component made of a material called a thickener for the purpose of holding a lubricating oil in a mechanical part to prevent outflow.

  However, even this grease product does not completely prevent oil oozing, and various base oil diffusion inhibitors have been proposed. For example, JP-A-8-176575 discloses a fluorosurfactant having a perfluorocarbon chain and having a polyoxyethylene as a hydrophilic group as an anti-diffusion agent for grease based on synthetic lubricating oil. Are listed. However, this fluorosurfactant was not sufficient in the base oil diffusion preventing performance.

  Japanese Patent Application Laid-Open No. 2000-109874 discloses a non-diffusible fluorine grease composition in which 0.1 to 50% of silicone oil is mixed with fluorine grease. However, sufficient anti-diffusion performance cannot be obtained with low-viscosity fluorine oil. In addition, the inclusion of silicone oil reduces the load bearing capacity, particularly between metal and metal, and there is a problem that the load bearing capacity of the fluorine oil is lowered depending on the amount of the blend.

JP-A-8-176575 JP 2000-109874 A

  The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a fluorine grease composition in which the diffusion of fluorine oil as a base oil is extremely small.

  As a result of examining the diffusion mechanism of fluorine oil, which is the main component of fluorine grease, the present inventor has obtained the following knowledge. The diffusion of fluorine oil starts from the adsorption of fluorine oil molecules on the surface of the member to which fluorine grease is applied. Therefore, in order to prevent the diffusion of fluorine oil, it was considered effective to adsorb different substances repelling with fluorine faster than fluorine oil molecules.

  As a result, as a substance effective in preventing the diffusion of fluorine oil, the kinetic speed is higher than that of the fluorinated oil molecule, that is, the molecular weight is lower, and the kinematic viscosity is equivalent to or less than that of the fluorinated oil as a physical property that substitutes the kinetic speed. In addition, it has been found that a substance having an adsorption force as a molecule stronger than that of fluorine oil and a numerical value of contact angle of fluorine oil or less as an evaluation criterion is desirable.

  Therefore, in the present invention, the silicone oil essentially having the above functions is used as a main component for preventing base oil diffusion, and a surfactant containing nitrogen is used in combination so that the silicone oil is applied to the surface of the applied member. It was found that the surface tension of the fluorine oil can be remarkably reduced, and the synergistic effect of the two has dramatically reduced the ability to prevent the diffusion of fluorine oil, which could not be achieved with silicone oil alone.

That is, in order to achieve the above object, the non-diffusible fluorine grease composition provided by the present invention contains 0.1 to 10% by weight of silicone oil in a fluorine grease containing a base oil and a thickener. This is characterized in that 0.1 to 5.0% by weight of a nitrogen-based surfactant is added. The silicone oil preferably has a kinematic viscosity at 40 ° C. of 1 to 500 mm ² / s.

  According to the present invention, it is possible to prevent the fluorine oil of the base oil from separating from the fluorine grease, and to significantly reduce the diffusion of the fluorine oil as compared with the prior art. Therefore, it is possible to provide a grease composition excellent in non-diffusibility, in which fluorine oil is present only in the portion to be lubricated and fluorine oil is not washed away in the other portions.

The non-diffusible fluorine grease composition according to the present invention is obtained by adding silicone oil and a nitrogen-containing surfactant to a normal fluorine-based grease that is made into a grease by adding a thickener to fluorine oil. The fluorine oil has roughly classified into linear type and side chain type, low viscosity kinematic viscosity from high viscosity products 1000 mm ² / s before and after, the kinematic viscosity at 40 ° C. of about 15 mm ² / s at 40 ° C. There are various types of goods. Moreover, polytetrafluoroethylene (PTFE) etc. are generally used as a thickener.

As the silicone oil used in the present invention, various conventionally known silicone oils such as dimethyl silicone oil, phenyl-modified, carboxyl-modified and amine-modified can be used. Among these silicone oils, kinematic viscosity preferably from 1 to 500 mm ² / s at 40 ° C., after a kinematic viscosity at 40 ° C. is less diffusion preventing effect is less than ^{1 mm} 2 / s, evaporation under a high-temperature or low vacuum It's easy to do. Also, when the kinematic viscosity at 40 ° C. exceeds 500 mm ² / s, the effect of preventing diffusion is reduced, which is not preferable.

  The blending amount of the silicone oil is in the range of 0.1 to 10% by weight of the whole fluorine grease composition. When the blending amount of the silicone oil is less than 0.1% by weight, the diffusion preventing effect cannot be obtained. On the other hand, when the blending amount of the silicone oil exceeds 10% by weight, the influence of the silicone oil becomes large, and the performance of the fluorine oil including the load bearing capacity decreases. On the other hand, if the silicone oil exceeds 10% by weight, the oil may be separated from the grease due to poor compatibility with polytetrafluoroethylene as a thickener.

  Examples of nitrogen-containing surfactants used in the present invention include amide fatty acid alkanolamides, fatty acid monoethanolamides, fatty acid triethanolamides, polyoxyethylene fatty acid amides, amine-based polyoxyethylene alkylamines, and alkylamine ethylene oxides. An adduct or the like can be preferably used. In particular, amine-based nitrogen-containing surfactants are preferable because they have a great synergistic effect on the improvement of diffusion preventing performance with silicone oil.

  The blending amount of the nitrogen-containing surfactant is in the range of 0.1 to 5.0% by weight of the whole fluorine grease composition. When the blending amount of the nitrogen-containing surfactant is less than 0.1% by weight, a synergistic effect for improving the diffusion preventing performance with the silicone oil is hardly recognized. Moreover, even if the blending amount of the nitrogen-containing surfactant is increased from 5.0% by weight, the effect of adding to the diffusion preventing performance reaches a peak.

Fluorine grease, thickener, silicone oil, and surfactant were mixed to prepare fluorine grease compositions having the compositions of Samples 1 to 9 shown in Table 1 below. As the fluorine oil as the base oil, demnum S-20 (dynamic viscosity is about 20 mm ² / s at 40 ° C.) manufactured by Daikin Industries, Ltd. was used. As the thickener, PTFE manufactured by Mitsui DuPont Fluorochemical Co., Ltd. was used.

Silicone oils are dimethyl silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. and have a kinematic viscosity of 20 mm ² / s (abbreviated as DMSO-20) and 350 mm ² / s (abbreviated as DMSO-350) at 40 ° C. Was used. As the nitrogen-containing surfactant, polyoxyethylene alkylamine (abbreviated as POEAA) and an alkylamine ethylene oxide (abbreviated as AAEO) adduct were used. Further, as a representative of the fluorosurfactant, perfluoroalkylcarboxylate (abbreviated as PFACA salt) effective as a diffusion inhibitor for poly-α-olefin grease was used.

  Sample 1 and Sample 2 are examples of the present invention and are fluorine grease compositions to which silicone oil and a nitrogen-containing surfactant are added. Samples 3 to 9 are comparative examples, and sample 3 is a normal fluorine grease obtained by thickening fluorine oil with PTFE. Samples 4 to 5 of the comparative examples are fluorine grease compositions to which only silicone oils having different kinematic viscosities at 40 ° C. are added and no nitrogen-containing surfactant is added.

  Samples 6 to 7 of the comparative examples are fluorine grease compositions to which only a nitrogen-containing surfactant is added and no silicone oil is added. Sample 8 of the comparative example is obtained by adding only a fluorosurfactant (perfluoroalkylcarboxylate). Furthermore, sample 9 of the comparative example is a fluorine grease composition to which silicone oil and the above-mentioned fluorine-based surfactant are added.

  The fluorine grease compositions of Samples 1 to 9 were tested for diffusion prevention performance. That is, a fluorine grease composition is applied to wrapping paper (# 2000) in a cylindrical shape having a diameter of 5 mm and a thickness of 1 mm, left in a thermostatic bath at 50 ° C. for 24 hours, and then spreads from the outer periphery of the cylindrical grease to the outside. The average distance to the end of the extracted oil was determined, and the results obtained are shown in Table 2 below.

  Since the sample 3 of the comparative example is a normal fluorine grease to which no diffusion inhibitor is added, the diffusion preventing effect of each fluorine grease composition is evaluated by comparing with the result of this sample 3. First, the fluorine grease compositions of Samples 1 and 2 which are examples of the present invention showed a significant improvement in the diffusion preventing effect as compared with Sample 3 of the comparative example.

  On the other hand, with respect to Comparative Samples 4 to 5 in which only silicone oil was added, Comparative Sample 8 in which only a fluorosurfactant was blended, and Comparative Sample 9 in which silicone oil and a fluorosurfactant were blended, Compared with the sample 3 of the comparative example, the improvement of the diffusion preventing effect was recognized in all cases. However, the anti-diffusion effect has improved only slightly, and has not reached the performance required conventionally.

  In addition, the fluorine grease compositions of Comparative Samples 6 to 7 are those containing only the nitrogen-containing surfactant used in the present invention. Even if only the nitrogen-containing surfactant is added, the anti-diffusion effect is obtained. Was hardly recognized. From the above, it can be seen that a fluorine grease having an extremely excellent anti-diffusion performance that sufficiently satisfies the required specifications can be obtained only by the combined use of silicone oil and a nitrogen-containing surfactant.

Claims (2)

  A non-aqueous composition characterized by adding 0.1 to 10% by weight of a silicone oil and 0.1 to 5.0% by weight of a nitrogen-containing surfactant to a fluorine grease containing a fluorine oil as a base oil and a thickener. A diffusible fluorine grease composition. The non-diffusible fluorine grease composition according to claim 1, wherein the silicone oil has a kinematic viscosity at 40 ° C. of 1 to 500 mm ² / s.