JPH0741786A - Heat-resistant lubricating composition and its production - Google Patents

Abstract

PURPOSE:To provide a heat-resistant lubricating composition which is excellent in heat resistance and can realize substantial shortening of heat treatment time. CONSTITUTION:A mixture of a lubricating grease with an ultra-high-molecular- weight polyolefin and a high-melting resin is heated with a dielectric heater to a temperature above the gel points of the polyolefin and the high-melting resin and then cooled to solidify. The high-melting resin serves as an internal heating element and permits substantial shortening of heating time. It also serves to improve the heat resistance of the composition since it melts and joins together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant lubricating composition used for rolling bearings and sliding parts of various equipment and a method for producing the same.

[0002]

2. Description of the Related Art As a heat-resistant lubricating composition, the applicant of the present invention has already proposed a composition in which a lubricating grease is blended with an ultrahigh molecular weight polyolefin, as disclosed in Japanese Patent Publication No. 63-23239.

This composition is prepared by blending lubricating grease with ultra-high molecular weight polyolefin, heating it to the melting temperature of the ultra-high molecular weight polyolefin using a heater (a constant temperature bath) using a heater, and then cooling it to a solid state. Had been turned into.

[0004]

The heat-resistant lubricating composition as described above is effectively used in rolling bearings and sliding parts of various equipment in place of semi-solid grease, and has some effects. .

By the way, in the above-mentioned lubricating composition, since the resin raw material constituting the lubricant is polyolefin, the heat resistance is limited, and the external heating by a thermostatic chamber or the like causes the thermal conductivity of the resin and the lubricating grease to be high. Therefore, even if the outside temperature is high, it takes a long time to uniformly heat the inside, and there is room for improvement that the heating cost is high.

Therefore, an object of the present invention is to provide a heat-resistant lubricating composition having excellent heat resistance and capable of shortening the heating time by changing the raw material resin and its composition and the heating method, and a method for producing the same. is there.

[0007]

In order to solve the above problems, the invention of a lubricating composition is to mix an ultrahigh molecular weight polyolefin and a high melting point resin into a lubricating grease to obtain an ultrahigh molecular weight polyolefin and a high melting point resin. After heating above the gel point of the resin, it is cooled and solidified.

Further, the invention of the method is such that a lubricating grease is mixed with an ultrahigh molecular weight polyolefin and a high melting point resin, and the mixture is heated by a dielectric heating device to a temperature above the gel point of the ultrahigh molecular weight polyolefin and the high melting point resin. It employs a configuration in which it is cooled and solidified.

[0009]

[Function] Lubricating grease is mixed with ultra-high molecular weight polyolefin and high melting point resin, and heated by a dielectric heating device, the high melting point resin becomes an internal heat source, and the heating time can be greatly shortened. Since the resins having the melting points are melt-bonded to each other, a heat resistant network can be formed in the lubricating composition.

[0010]

Embodiments of the present invention will be described below.

The heat-resistant lubricating composition of the present invention is obtained by mixing the lubricating grease with the powder of the ultrahigh molecular weight polyolefin and the powder of the high melting point resin, and heating the mixture by high frequency to gelate the ultrahigh molecular weight polyolefin and the high melting point resin. It is formed by heating above the point and then cooling and solidifying.

As the lubricating grease, one having a dropping point higher than the melting temperature of the ultrahigh molecular weight polyolefin and the high melting point resin is used, and as the ultrahigh molecular weight polyolefin powder,
Ultra high molecular weight polyethylene can be illustrated.

Further, as the high melting point resin, one having a large product of the dielectric constant ε and the dielectric loss tangent tan δ with respect to a high frequency such as nylon, polyacetal, polyester or the like is used.

To produce a heat resistant lubricating composition, the lubricating grease is added in an amount of 1.5 to 69.3 wt% and an average molecular weight of 1 × 1.
28.5 to 0.3 wt% of ultra high molecular weight polyolefin powder of 0 ^{6 to} 5 × 10 ⁶ and powder of high melting point resin 30 to 7
0 wt% was mixed and the composition was mixed at a frequency of 100 KHZ.
Using a dielectric heating device of ˜2450 MHHKZ, high frequency heating is performed at a temperature higher than the gel point of the ultrahigh molecular weight polyolefin and the high melting point resin, and then cooling is performed to solidify.

By high frequency heating the above composition,
If necessary, the oscillation frequency can be changed and efficient heating becomes possible.

That is, since the ultra high molecular weight polyolefin resin has low values of both the dielectric constant ε and the dielectric loss tangent tan δ, high-frequency heating was not possible with a compound prepared by mixing it with a lubricating grease.

On the other hand, according to the present invention, by mixing the lubricating grease with the ultra-high molecular weight polyolefin and the high melting point resin, the resin having a high melting point and a large product of the dielectric constant ε and the dielectric loss tangent tan δ becomes a heating element, and high frequency heating is performed. Internal heating by means of, and by using the uniformly dispersed high melting point resin fine powder as the internal heat source, the heating time is greatly shortened, and since this high melting point fine powder is melt-bonded to each other, A heat resistant network can be formed in the lubricating composition, and by cooling after the heating, a composition excellent in heat resistance and lubricity and suitable for use in rolling bearings and sliding members can be obtained. .

In the thermoforming of the above composition, by employing a dielectric heating device, for example, the space in the bearing can be heated in a state of being filled with the compound, the molecular motion of the mixture is stimulated, and the bearing itself is not heated. The formulation can be heated and the lubricating composition can be directly fired into the bearing to solidify.

If the blending amount of the high melting point resin fine powder is small, the effect as a heat source is reduced, and if it is too large, the amount of lubricating grease and the amount of polyolefin serving as a holder for these are reduced, so that it is too small. Too much or too much is not good. When the total amount of the raw materials is 100, the proportion of the high melting point resin is preferably 30 to 70%.

Example 1 60 g of lubricating grease, 20 g of ultra-high molecular weight polyethylene, and 20 g of 11-nylon fine powder (Rilsan ES natural average particle size 110 μm) were thoroughly mixed to prepare a grease-like compound. A portion (1 g) of this formulation was dispensed into a magnetic vessel and set in a microwave oven. It was heated at an output of 500 W for 6 minutes. This treatment caused the formulation to heat set and become a solid. The hardness of this solid was 80 Hs at room temperature.

Example 2 Lubricating grease (50 g), ultra high molecular weight polyethylene (20 g), and 11 nylon fine powder (Rilsan ES natural (average particle size: 110 μm) (30 g) were mixed well to prepare a grease-like composition. A part (1 g) was placed in a magnetic dish and set in a microwave oven.The mixture was heated at an output of 500 W for 4 minutes and then cooled to room temperature.This treatment cured the composition, and the hardness at room temperature was 92 Hs.

In Examples 1 and 2, neither weight change nor oil separation was observed during the heat treatment process.

[0023]

As described above, according to the present invention, the lubricating grease is mixed with the ultrahigh molecular weight polyolefin and the high melting point resin, and the mixture is heated and cooled to be solidified, so that the high melting point resin generates heat. Since it becomes a body and the inside can be heated, the heating time can be greatly shortened.

Further, since the high melting point resins are melt-bonded to each other, a composition having excellent heat resistance can be obtained, and high frequency heating can be adopted for heating, so that the composition can be safely and efficiently heated.

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Claims (2)

[Claims] 1. A lubricating grease is mixed with an ultrahigh molecular weight polyolefin and a high melting point resin, heated to a temperature above the gel point of the ultrahigh molecular weight polyolefin and the high melting point resin, and then cooled,
A solidified heat-resistant lubricating composition. 2. Lubricating grease is mixed with an ultrahigh molecular weight polyolefin and a high melting point resin, which is heated by a dielectric heating device to a temperature above the gel point of the ultrahigh molecular weight polyolefin and the high melting point resin, and then cooled and solidified. A method for producing a heat-resistant lubricating composition, comprising: