JPH02300293A - Grease composition with improved low-temperature flow property and plastic resistance - Google Patents

Abstract

PURPOSE:To improve low-temp. flow properties and plastic resistance by compounding a base oil wherein a paraffin mineral oil with specified pour pt., aniline pt. and viscosity is a main component with, if necessary, a thickening agent, a rustproofing agent, etc. CONSTITUTION:Only paraffins which impair low-temp. flow properties are selectively incorporated in a zeolite catalyst from a paraffin mineral oil and catalytic hydrocracking thereof is performed to remove them as an intermediate distillate such as naphtha or LP gas and to obtain a paraffin mineral oil (a) with a pour pt. of -30 to -60 deg.C, an aniline pt. of 95-120 deg.C and a viscosity (at 40 deg.C) of 5-120cSt. A base oil with the component (a) as a main component is obtd. by compounding the component (a) with if necessary, a synthetic oil, a naphthene mineral oil, etc. The base oil is, if necessary, compounded with a thickening agent, an antioxidant, an extreme-pressure additive, a rustproofing agent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a grease composition with improved low-temperature fluidity and plasticity resistance. In other words, a grease composition that can be used in equipment made of various plastics and maintains good lubricity without damaging the material, and also maintains stable grease properties over a wide range from low to high temperatures. It is related to.

[Prior art] With the rapid progress toward high performance and miniaturization of precision equipment in recent years, there has been a need for grease used in the rotating and sliding parts of these equipment. , excellent performance matching these characteristics has come to be required. In other words, as we move toward miniaturization, the motors, various bearings, switches, and other parts that make up the mechanical parts of various devices also become smaller, and the energy used to drive them achieves performance with less force. It is designed to be possible.

Along with this, the lubricating grease used in each of these parts not only has temperature-dependent properties such as heat resistance and low temperature properties, but also has low friction and low torque properties to bring out the performance of the equipment. This becomes especially important when doing so. As a means of meeting these demands, there is a growing trend to use synthetic oils, and low-viscosity oils are also used as base oils for greases, which reduce tor and enable use in a wide temperature range from low to high temperatures. Designed to be.

However, when synthetic oils are used as base oils, various problems arise. The first is the high price, and the second is the resistance to plastics. Here, plastics in the present invention include general-purpose plastics such as polystyrene resin, ABS resin, polyvinyl chloride resin, and other special plastics, as well as synthetic rubbers such as urethane rubber and silicone rubber. shall be held.

Plasticizers are generally used in various plastics to make them flexible. Guester oil, which is often used as a base oil for grease, is a plasticizer itself, and is used in greases that require low-temperature properties. Because plasticizers dissolve in plastics, they have the effect of swelling or deforming the plastics themselves, and the degree of this effect is related to the properties of the plastics and oil.

For example, silicone rubber is affected by silicone oil, but not by other synthetic oils, and general-purpose plastics used in various devices are not affected by linear synthetic oils. Although it is not so affected, various ester oils, synthetic oils with a cyclic hydrocarbon structure, and mineral oils are significantly affected.

Therefore, as the base oil for plastic-resistant grease, linear hydrocarbon-based paraffinic mineral oils, α-olefin-based oils, vegetable oils, and the like are used. Conversely, base materials that swell plastics include naphthenic mineral oils, ester oils, etc., and these cannot be used in plastic-resistant greases.

For the above reasons, it is necessary to use raw materials that do not affect these base materials for plastic-resistant and rubber-resistant greases, which naturally results in limitations.

Also, when considering use in a wide temperature range, there are not many synthetic oils that can withstand from low to high temperatures; those with good low-temperature performance become unstable at high temperatures, and conversely, those with good high-temperature performance have poor low-temperature performance. A problem arises in terms of.

Therefore, when a synthetic oil is selected under the conditions of plastic resistance and usability over a wide temperature range, there are many problems and satisfactory results are not always obtained.

Furthermore, when synthetic oil is used as a base oil, it has poor compatibility with the thickener, and in addition, when low viscosity oil is used, the bad relationship between the two is amplified, resulting in increased oil bleed from the grease. However, oil leaks even to parts that do not require lubrication, causing an undesirable phenomenon of contamination.

Considering only low-temperature properties, naphthene-based mineral oils can be used as a base to provide a grease composition that has good low-temperature fluidity and can be used at temperatures as low as -30 degrees Celsius. can. When these naphthenic mineral oils are used as a base oil, a structurally stable grease composition can be obtained, and it can be used in a range from low temperatures to a certain high temperature range, i.e. 150
Stable properties can be maintained up to about 100°C. However, at higher temperatures, it becomes unstable and cannot maintain its properties. Furthermore, when these naphthenic mineral oils are used, they swell materials such as resins and rubbers, so there is a problem that they cannot be used in devices using materials other than metals.

In addition, commonly used greases based on paraffinic mineral oil have good compatibility with thickeners, high temperature stability, and good plastic resistance.
It has the problem of not being able to flow at low temperatures.

5 synthetic oil as a base oil for grease.

Both naphthenic mineral oil and paraffinic mineral oil have their own problems as described above, and satisfactory results have not always been obtained.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems, and can be used in equipment using various plastics to maintain good lubricity without damaging the material, and to maintain good lubricity at low temperatures. It is an object of the present invention to provide a grease composition with improved low-temperature fluidity and resin resistance, which is characterized by maintaining stable grease properties over a wide range from low to high temperatures.

[Means for Solving the Problems] In order to solve the above problems and achieve the object of the invention, the grease composition with improved low-temperature fluidity and resin resistance according to the present invention is configured as follows. It is characterized by That is,
The main component is isoparaffin, and the pour point is 130 degrees C~-
60 degrees C, an aniline point of 85 degrees C to 120 degrees C, 40 degrees C (7) and a paraffinic mineral oil having a viscosity of 5 to 120 cSt as the main base oil.

[Example] The present invention will be explained in detail below using examples.

The grease composition according to this example contains isoparaffin as a main component, has a pour point of 130 degrees C to -60 degrees C, an aniline point of 95 degrees C to 120 degrees C, and a viscosity of 5 to 12 degrees C.
The base oil is mainly paraffinic mineral oil with 0 cSt.

The paraffinic mineral oil according to this example is produced by selectively incorporating only the paraffins that inhibit low-temperature fluidity in conventional paraffinic mineral oil, which is a raw material, into a zeolite catalyst, and catalytically hydrocracking it to produce intermediates such as naphtha. It can be obtained by removing it as a fraction or LP gas.

Zeolite catalysts are crystalline substances mainly composed of silicon atoms, aluminum atoms, and oxygen bonds connecting these atoms, and are characterized by having many uniform pores within the crystals. An example of such a zeolite catalyst is a zeolite ZSM-5 catalyst having a 10-membered ring pore structure published by Mopil Oil.

This catalyst is a normal paraffin with a thin linear molecular structure among petroleum hydrocarbons that exhibit extremely good molecular shape selectivity because it effectively controls the entry and exit of reaction molecules and reaction product molecules into the pores. Paraffins with large branches and slightly branched paraffins can enter the pores of zeolite, but isoparaffins with large branches and hydrocarbons with a cyclic structure cannot enter into the pores. In this method, only paraffins that inhibit low-temperature fluidity are selectively incorporated into a catalyst, subjected to catalytic hydrogenolysis, and removed as middle distillates such as naphtha or LP gas. This production is carried out, for example, using a Mobil catalytic dewaxing MLD system (Mobil Loop Def-2 Sink). Isoparaffins with large branches and hydrocarbons with a cyclic structure that cannot enter the pores of the zeolite catalyst are not decomposed and remain in the treated oil, resulting in a low pour point of the paraffinic mineral oil obtained.

As mentioned above, isoparaffins with large branches and hydrocarbons with a cyclic structure have good low-temperature performance, but in the solvent film waxing method, even the components that are effective for low-temperature performance are removed. Depending on the waxing method, it is not possible to obtain a grease with good performance as in this example.

The paraffinic mineral oil used in this example has a pour point of 130 degrees Celsius or more.
-60 degrees C, the aniline point is 85 degrees CN and 120 degrees C, but the pour points of conventional paraffinic mineral oils and naphthenic mineral oils are -5 degrees C to -15 degrees C, 1-10 degrees C to -40 degrees C, respectively. The aniline point of conventional paraffinic mineral oil, naphthenic mineral oil, and aromatic mineral oil is 100 degrees C ~
130 degrees C180 degrees CN 100 degrees C160 degrees C~85
degree C, and the paraffinic mineral oil of this example is different from conventional paraffinic mineral oils, naphthenic mineral oils, and aromatic mineral oils. Table 5 shows the differences in properties between the paraffinic mineral oil of this example and conventional paraffinic mineral oils, naphthenic mineral oils, and aromatic mineral oils.

As the base oil, synthetic oil, naphthenic mineral oil, etc. may be blended with the paraffinic mineral oil whose main component is isoparaffin. Examples of synthetic oil include diesters such as dioctyl sebacate, aliphatic monocarboxylic acids, etc. Examples include ester oils such as tetraesters such as pentaerythritol esters, polyolefin oils such as polyα-olefins, polyglycol oils, polyphenyl ether oils, silicone oils, halogenated hydrocarbon oils, and alkylbenzene oils.

In addition to the above-mentioned base oil, the grease composition according to this example may contain various commonly added additives as necessary. For example, thickeners, antioxidants, extreme pressure additives, rust preventive additives, etc. Add agents, etc. as appropriate.

Examples of the thickener include conventionally known metal soaps, inorganic cumulative thickeners, organic thickeners, and the like.

The metal parts of metal soap include sodium, potassium, calcium, barium, strontium, aluminum,
The fatty acid portion of the metal soap includes various fatty acids, fatty acid mixtures, and so-called complex soaps that combine fatty acids with other acids such as acetic acid, benzoic acid, boric acid, dicarboxylic acid, and salicylic acid. types can be listed. These fatty acids are generally obtained by decomposing glycerin esters contained in animal fats, vegetable oils, waxes, etc., or are artificially produced chain fatty acids. Typical examples of such fatty acids include saturated fatty acids such as myristic acid, palmitic acid, and stearic acid, unsaturated fatty acids such as oleic acid, and fatty acids such as 12-hydroxystearic acid.

Examples of inorganic thickeners include bentonite, colloidal silica, silica aerogel, alumina, graphite, mica, talc, clay, diatomaceous earth, and the like.

Examples of organic thickeners include urea cumulative thickeners and the like. Typical examples include diurea and tetraurea. Examples of other organic thickeners include urea-based, indanthrene-based, phthalocyanine-based, and amerin-based thickeners.

Further, the grease composition according to the present example may contain various additives that are normally added as needed. For example, antioxidants, extreme pressure additives, rust preventives, etc. may be added as appropriate.

[Examples 1, 2, 3 and Comparative Example 1, ? , 3] A grease composition based on the formulation shown in Table 1 is prepared by the following method.

First, approximately 273 of the total amount of base oil, 12-hydroxystearic acid, and all of stearic acid are charged into a pot, heated, and stirred. After fatty acids are dissolved 85
At ~85 degrees C, lithium hydroxide is added as an aqueous solution. This amount of lithium hydroxide is the amount necessary to completely neutralize the fatty acids. This step allows the fatty acids to react with the lithium hydroxide, allowing enough time to form what is known as lithium soap. After the dehydration process, heating and stirring are continued, and the temperature is finally raised to 180 to 200 degrees Celsius, after which heating is stopped. At this point, add the remaining base oil and cool quickly. Stirring was continued, and additives such as antioxidants were added at 120 degrees Celsius or lower, mixed uniformly, and then passed through a disper mill to obtain a grease composition.

[Example 4.5 and Comparative Example 4.5] Grease compositions based on the formulations shown in Table 2 are prepared in the following manner.

Example 4 and Comparative Example 4 are aluminum composite type greases, which are prepared in the following manner.

First, the entire amount of base oil, benzoic acid, and stearic acid are poured into a pot, heated, and stirred.

Acids dissolve at around 80 degrees Celsius, but by raising the temperature further,
Aluminum oligomer (trioxy-
In order to completely terminate the reaction of adding (aluminum tri-isopropoxide), the temperature is slowly raised to a maximum heating temperature of 185 to 195 degrees Celsius, heating is stopped, and stirring is continued thereafter. Add the antioxidant at below 120 degrees Celsius, mix uniformly and then apply it to a disper mill.
A grease composition was obtained.

Example 5 and Comparative Example 5 were prepared using organic bentonite greases in the following manner. First, add 172 of the total amount of base oil and organic bentonite additive, Balaguer (trademark, manufactured by Nashikinal Red Corporation), and stir well.Next, add the remaining base oil little by little and take a while. Add the entire amount.

During this step, special care must be taken to ensure uniform mixing and thorough stirring is required.Methanol is then added and stirred thoroughly to ensure thorough mixing.

After uniformly mixing, heating is started, methanol is removed, and the temperature is raised to 100 degrees Celsius and held for 15 minutes before being extinguished. After mixing thoroughly, additives such as antioxidants are added, and when the mixture becomes uniform, it is passed through a three-stage roll to complete the adjustment.

In the above examples, Swanox (trademark, manufactured by Seio Chemical Co., Ltd.) was used as the antioxidant. In addition, the properties of the paraffinic mineral oil used in this example were
Table 4 shows the properties of the raw material oil used in the comparative example. The paraffinic mineral oil of this example shown in Table 3 was manufactured by Mobil Oil Co., Ltd. and was manufactured using a Mopil catalytic dewaxing NJW (Mobile Loop Dewaxing) device. In addition, 101
0.1022 etc. is the product number.

Tables 1 and 2 show the properties of the obtained grease compositions. A low-temperature torque test was conducted to evaluate low-temperature fluidity, and a styrene foam test was conducted to evaluate plastic resistance, and the results are shown below.

Table 1 Table 2 - One Eaves LjL - Eaves 1 - Person 1 Examples 1 to 5 are all related to the present invention, all passed the Styrofoam test, and have excellent plastic resistance. Furthermore, a relatively low value was obtained in a low-temperature torque test at -40 degrees Celsius, indicating that the low-temperature fluidity is excellent.

On the other hand, Comparative Examples 1.4.5 used conventional paraffinic mineral oil as the base oil, and had excellent plastic resistance but poor low-temperature fluidity. In Comparative Example 2.3, naphthenic mineral oil and Guester mineral oil were used as the base oil, but both had low values in the low-temperature torque test and good properties in the low-temperature range, but failed the styrofoam test. , indicating that the influence on the resin is large.

[Effects of the Invention] Since the grease composition of the present invention with improved low-temperature fluidity and plastic resistance is configured as described above,
Used in equipment made of various plastics, it maintains good lubricity without damaging the material, and
It has the effect of maintaining stable grease properties over a wide range of temperatures, from low to high temperatures.

Claims (1)

[Claims] Main component is isoparaffin, pour point is -30 degrees C~-
60 degrees C, aniline point is 95 degrees C to 120 degrees C, viscosity is 5 to 120 cSt at 40 degrees C, paraffinic mineral oil is used as the main base oil.It has improved low temperature fluidity and plastic resistance. Grease composition.