KR20130072780A - Developement nano hybrid grease having high temperature and high load-carrying property - Google Patents

Abstract

PURPOSE: A solid lubricating grease for high temperature and heavy load is provided to improve heat resistance, leakage resistance and load endurance as enabling high temperature, heavy weight and long-term lubrication. CONSTITUTION: Diurea is synthesized by adding a reaction raw material of thickener to base oil and then performing heating/stirring for reaction. Additive is blended to the Diurea. The additive is obtained by mixing one or more than one of nano complex solid material comprising graphite, boron compound, bentonite compound, molybdenum compound and polytetrafluoroethylene (PTEE) compound. The nano complex solid material mixes grease raw material comprising the base oil and the thickener at a ratio of 0.5-5 % for 95-99.5 %. [Reference numerals] (AA) Test item; (BB) Worked penetration,; (CC) Drop point,; (DD) Oil separation; (EE) Oxidation stability; (FF) Copperplate corrosion; (GG) Unit; (HH) German product; (II) Japanese product; (JJ) Invention middle submission (nanocarbon non-addition); (KK) Invention product; (LL) Note

Description

Development nano hybrid grease having high temperature and high load-carrying property

The present invention relates to a solid lubricating grease for high temperature and high load, and more particularly, to provide a grease capable of faithfully performing its function even when exposed to high temperature and high load, thereby improving operability of an industrial facility using grease while creating high added value. It is about the provision of one Greek to help.

For high temperature, high load and long-term lubrication, Large Open Type Gear, Low Speed Rolling Bearing, High Temperature Bearing, High Temperature Gear, Chain Large Bearing, Bolts, Pin, Bushings, Hot Hinge Parts, Hot Gate Parts, Rolling by Heat Treatment Bearings and bogie bearings.

Greases used in such components, devices, or materials are widely used as lubricants having various lithium, lithium complex, calcium, urea groups, etc., but generally exhibit problems such as heat resistance, leakage resistance, and load resistance.

Currently, the demand for special lubricants applied to domestic industrial facilities depends on imports or is produced through technical cooperation with foreign companies, so domestically developed products are rarely produced.

In addition, major domestic heavy industry and infrastructure equipment and parts are mainly dependent on imported goods, which is not only high in price, but also inadequately responding to customer requirements and market changes.

The development status of special lubricating oil technology in Korea has been developed a lot based on the long experience in the field, but the level of technology development is poor due to lack of standardization and lack of professional manpower. We are making efforts to improve quality through alliance, but there is limited technology sharing in foreign technology alliances, and it is not possible to respond immediately to customer's demand, and development of grease requiring various physical properties is sluggish.

In the present invention, to solve the problems as described above, by adding a reaction raw material of the thickener to the base oil and reacted by heating and stirring to synthesize the diurea and then blending the additives to prepare;

The additive is one of one or more nanocomposite solid materials consisting of graphite, boron compound, bentonite compound, molybdenum compound, and polytetrafluoroethylene compound. By obtaining grease, it is possible to achieve high temperature, high load, long-term lubrication, and to improve heat resistance, leakage resistance, and load resistance.

The present invention as described above can contribute to the improvement of analysis ability of raw materials and subsidiary materials, and the improvement of the operational capability of test equipment, leading to the production of high value-added products, and raising the current technology development capability to the next level. In response to the development of technology that can secure competitiveness with domestic and foreign manufacturers and complement the mutual shortcomings of grease, it is connected with the development of thickener and new additive suitable for grease properties. Has the effect of.

In addition, it can not only contribute to the increase of sales through the development of new products in Korea, but also create a new market, build an export base with the substitution effect of lubricant import used in the domestic industry, and import lubricant of domestic industrial equipment and parts manufacturers. Generally, various effects can be obtained with economic effects that can greatly contribute to the reduction of production cost of equipment parts companies.

1 is a comparative test results of the grease of the grease produced by the technology of the present invention and commercially available (imported) products.
Figure 2 is a label showing the test report of the grease produced by the technique of the present invention.
Figure 3 is a result table showing the test report of the grease produced by the technique of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a comparative test results table of grease produced by the technique of the present invention and grease (imported), Figure 2 is a label showing a test report of the grease produced by the technology of the present invention, Figure 3 The test report of the grease produced by the technique of the present invention will be described together as a result table showing.

The high-temperature, high-load solid lubricating grease to which the technique of the present invention is applied is prepared by mixing polyurea grease by adding a reaction material of a thickener to base oil and stirring it by heating and stirring to synthesize diurea, and then blending additives.

Worked penetration (0.1 mm); 220-240

Drop point (° C); > 290

Base oil; Mineral oil + synthetic oil

Weaning degree (Oil separation 100 ° C./24hr); <1.5

Oxidation stability MPa; > 0.03

It is characterized in that to satisfy the standards such as.

The process of making grease is as follows.

Base Oil

Heat-resistant greases often use synthetic oils Alkylbenzene and mineral oil Paraffin hydrocarbons as base oils, which are classified according to the nature of the alkyl groups. In general, higher hydrocarbons have reduced thermal fluidity and increase viscosity due to intermolecular Van der Waals Attraction.

Aromatic hydrocarbons, rather than aliphatic hydrocarbons, have high viscosity due to their mutual attraction between molecules, and are excellent in chemical stability and excellent in heat resistance. Commercially available viscosity products are formulated according to the constituents of the alkyl groups and they are mixtures of similar hydrocarbon compounds. Grease base oils that require heat resistance can obtain characteristics of heat resistance and basic viscosity by controlling Alkylbenzene in a certain ratio with respect to Paraffin Base Oil.

Therefore, since base oil is not composed of a single pure compound, it can be easily predicted according to the viscosity of a commercial product rather than chemical analysis, and base oil composition necessary for viscosity can be obtained by adjusting the composition of the base oil based on the characteristics of the final product.

In the present invention, as a paraffin base oil, the kinematic viscosity of 15-30 carbon number 100 cSt (at 40 ℃) and the 15-50 kinematic viscosity of 460 cSt (at 40 ℃) Alkylbenzene base oil is an alkyl group of 4-16 carbon number of 4-16 The composition was adjusted using cSt (at 40 ° C).

Additives

It can be classified as affecting the physicochemical properties of base oils or affecting the metal surface. Base oil, the main component of grease, is a hydrocarbon-based compound, which is oxidized by external factors and loses viscosity. Therefore, an antioxidant is added, and an anti-corrosive agent, an oil film forming agent, and an anti-wear agent on the surface of the metal material of the lubrication part is added.

Thickener

Diurea, which gives viscosity to base oils, is synthesized by reacting amines with diisocyanates, and classified into Aliphatic Diurea, Alicyclic Diurea, and Aromatic Diurea, depending on the type of amine.

(A) Aromatic Diurea has a very stable crystal structure between molecules due to the chemical stability and hard physical properties of the aromatic ring, which can minimize the amount added to the lubricant due to its excellent thermal stability, adhesion, leakage resistance and shear stability. But fluidity and pressure are low.

(B) Aliphatic urea (Aliphatic Diurea) is a hydrophobic, fluidity and weak force of van der Waals only of aliphatic hydrocarbons, less molecularly compatible than aromatic urea. Therefore, although the characteristics of the lubricant as a thickener are less than that of aromatic urea, it is mainly used for high temperature steelmaking because of its excellent fluidity and pressure.

(C) Cyclic saturated hydrocarbon urea (Alicyclic Diurea) has rigid physical properties due to the lower degree of conformational freedom than the molecular properties of the chained aliphatic hydrocarbons, but does not reach aromatics. Therefore, the thickener has the physical and chemical properties between aromatic and aliphatic.

Using the above materials,

About 85% of the base oil is added to the reactor, and the mixture is heated and stirred at 45 to 55 ° C., MDI is added and the solution is dissolved in a transparent manner.

Oleylamine and Octylamine were added to the remaining 15% of the base oil in the vessel and stirred, and the mixture was quickly added to the reactor and stirred at a high speed.

At this time, since the temperature inside the reactor is increased by the reaction heat, the gastric solution is added at the state of heating off and cooling water.

Stir at a rate of 50 ~ 60Hz for 50 ± 5 minutes while cooling the temperature inside the reactor below 75 ℃, turn off the cooling switch and turn on the heating switch to heat up to 180 ± 5 ℃ step by step (about 10 ℃ / 30 minutes) And keep stirring for 10 ± 3 minutes. Cool by turning off the heating switch and starting the cooling switch of the reactor.

The antioxidant is added and stirred between 130 and 140 ° C, and the corrosion inhibitor and the extreme pressure additive solid lubricant are added and stirred at 60 to 70 ° C. The reactant is processed twice by using a 43㎛ filter and roll mill and adjusted to 220 ~ 240 as desired.

In the present invention, the nano-composite solid material is mixed with the additive to sufficiently endure high temperature and high load, and the nanocomposite solid material is graphite, boron compound, bentonite compound, molybdenum, and molybdenum. One or more of the compound and polytetrafluoroethylene (PTFE) compound may be used in combination.

The mixing ratio of the nanocomposite solid material may be completed by mixing a grease raw material consisting of a base oil and a thickener in a ratio of 0.5 to 5% with respect to 95 to 99.5%.

The high-temperature, high-load solid lubricating greases prepared as described above were compared with the imported greases on the market through mild casting, dropping point, reasoning degree, oxidation stability, and copper plate corrosion test.

Mixed Race Test

The thinner degree of lubricating oil is expressed as viscosity, while the grease is semisolid, so the soft and hard degree is expressed as Penetration. The headlight is used to wipe the cone with a defined weight and angle on the surface of the sample in the specified container. At this time, the depth of the cone penetrated for 5 seconds by dropping the cone, measured in millimeters, is 10 times the value of mm. To be displayed. Conventional led refers to a mixed lead measured immediately after 60 minutes of mixing for 1 minute using a specified grease comparator while maintaining the sample at a temperature of 25 ± 0.5 ° C. The lead measured without mixing is called a mixed lead.

Solid-state is especially applied to hard grease of 85 or less in the main province, measured in the form of blocks in the specified dimensions, and found to be 232 according to the relevant standards of KS M ISO 2137, ASTM D217, and ASTM D1403.

Test of redness

Dropping Point is the first temperature at which grease temperature rises and changes from semi-solid state to liquid state. It is not a direct indication of the maximum limit of grease that can be used for bearings, and grease cannot be used up to the dropping point temperature.

The dropping test of grease can be used as a criterion for judging the heat resistance in terms of use, and the dropping point of grease having the same mixing ratio is almost constant and thus used as a quality control standard in the manufacturing process.

The most important factor affecting the dropping point is the type of thickener, and in the case of the same thickener, the base oil content, the type and content of fat or fatty acid as a thickener raw material, and a manufacturing method.

In general, when using grease, it is common to use grease with a dropping point higher than the temperature at the place of use, and in general, it is appropriate to view 60 to 70% of the dropping point as the maximum operating temperature. On the other hand, soap-based grease is different from the net structure of the thickener as soap-based and is combined with base oil.

Therefore, it does not apply to soap-based greases, such as benton greases, as they do not tend to change into a fluid state when heated. As a result of testing according to the relevant standard of KS M ISO 2176, ASTM D 2265, it showed 290 ℃.

Reason also test

The Oil Separation test shows that the oil will gradually separate and seep into the surface of the grease after long-term preservation of the grease. This phenomenon is called weaning or oil separation and is called the storage stability of grease.

Most tests to determine the reason for grease are methods in which the grease is left at a constant temperature for a specified time and then the weight percentage of the oil separated from the grease. These test methods measure the reasons for static conditions and are not dynamic, such as those used in bearings.

The method of measuring the reason for the grease in the dynamic state is the ASTM D4425 test method, which indicates the amount of oil separated by applying centrifugal force to the grease using a centrifuge.

Unlike the general test method, this test method can predict the result most similar to the actual lubrication condition. The reason for the storage or actual use of greases is very complex, including factors such as grease profile, type of thickener, soap content, fiber structure, kinematic viscosity and type of base oil, temperature conditions and pressure or force on grease. It happens by acting.

In fact, too many greases in the test are not desirable for a variety of reasons, but some are necessary for lubrication. The results of testing to the relevant standard of KS M 2050 showed that there was no oil separated from the grease at zero.

Oxidation Stability Test

The oxidation stability of grease (Oxidation Stability) is the three components, such as base oil, thickener, and additives are related to each other, but most of the additives used to improve the oxidation stability of the base oil.

Greases used in products such as bearings are often stored and sold after injecting grease when bearings are manufactured for a long time. In this case, the electric field oxidation stability of grease is very important.

According to the relevant standard of KS M 2049, take 4g of grease in 5 thin glass plates and put them inside the sealed bomb and react with oxygen at the oxygen pressure of 0.76MPa at 99 ℃. Oxygen is absorbed as the oxidation proceeds. The pressure drop is reduced and oxidative stability is assessed by this pressure strengthening, which is usually tested for 100 hours.

As a result of the test, it was found that the hot lubricating solid lubricating grease to which the technique of the present invention was applied was superior to commercial samples imported at 0.014 MPa.

Copper plate corrosion test

This test evaluates the effect of grease on the lubrication area. The purpose of the test is to check the degree of purification of grease and the presence of sulfur compounds and oxides.

The copper corrosion test method of KS M 2088 is inserted into the test tube filled with the sample until the upper end of the copper plate is completely submerged.Then, it is maintained vertically and maintained for 24 hours in a constant temperature oven at 100 ± 1 ℃. do.

After the test, remove the test tube, cool it to room temperature, remove the copper plate with stainless tweezers, and examine the discoloration of the sample. The copper plate is then washed with a solvent to remove the attached sample and then examined for changes in the copper plate. According to the degree of discoloration, it was classified into a grade from 0 to 5, and the high-temperature high-load solid lubricating grease was 0.

As a result of the above physical property test, the grease finished by adding nano-composite solid material was able to confirm the superior performance compared to the sample that is imported and sold in the heat resistance, leakage resistance, load resistance and bearing life test.

Claims (2)

A reaction material of a thickener is added to the base oil, followed by heating and stirring to synthesize diurea, followed by blending with an additive;
The additive is obtained by mixing one or more nanocomposite solid materials consisting of graphite, boron compound, bentonite compound, molybdenum compound, and PTFE (polytetrafluoroethylene) compound. Solid lubricating grease for high temperature and high loads. The method of claim 1, further comprising:
The nano-composite solid material is a high-temperature, high-load solid lubricating grease, characterized by mixing a grease raw material consisting of a base oil and a thickener in a ratio of 0.5 to 5% with respect to 95 to 99.5%.

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