JPH0633394B2 - Method for producing self-lubricating composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a self-lubricating composition comprising a lubricating oil and ultra-high molecular weight polyethylene, and particularly, excellent lubrication under low-speed and high-load conditions. The present invention relates to a method for producing a self-lubricating composition exhibiting performance.

[Prior Art] Solid lubricants such as molybdenum disulfide and graphite are usually used in places where it is difficult to directly apply the lubricant, such as bush liners. It has a poor wedge effect, and it is difficult to provide excellent lubrication performance for a long period of time under low-speed and high-load conditions.For example, rotating elements, bearings, sliding bearings of various types, and wires. Even for lubrication of mechanical elements related to transmission devices such as ropes, screws, chain drives, gears, etc., lubricating oil is continuously and effectively supplied to the sliding surface over a long period of time to provide excellent lubrication performance. It is difficult to do.

Therefore, conventionally, as a solution to such a problem, an ultra-high molecular weight polyolefin and a mineral lubricating oil are mixed, heated and melted, and then the melted mixture is cooled and solidified, whereby an ultra-high A self-lubricating composition (Japanese Examined Patent Publication No. 47-3455) in which a lubricating oil is impregnated in a molecular weight polyethylene so that the impregnated mineral lubricating oil exudes has been proposed.

However, in this conventional self-lubricating composition,
Depending on the viscosity (40 ° C) of the lubricating oil used is 100 cst. Or more, or depending on its type, when this lubricating oil and ultra-high molecular weight polyethylene are heated and melted, the raw material system is melted until completely melted. It takes a long time,
Part of it, especially the central part, remains without melting,
In some cases, it may hardly melt, and the properties and lubricating performance of the obtained self-lubricating composition after solidification may become non-uniform, or it may be impossible to mold with almost no solidification. There was a problem.

Therefore, the inventors of the present invention have conducted extensive studies as to the cause of such a problem, and as a result, found out that air was entrained and mixed when the lubricating oil and the ultra high molecular weight polyethylene were mixed, and further mixing was performed. The present invention has been accomplished by developing a method for preventing the inclusion of air at times.

[Problems to be Solved by the Invention] Accordingly, an object of the present invention is to prevent air from being mixed in when a lubricating oil and ultra-high molecular weight polyethylene are mixed, and thereby to heat-melt the lubricating oil and the ultra-high molecular weight polyethylene. In order to shorten the melting time and complete melting, the properties of the self-lubricating composition after solidification and the lubricating performance are uniform, so that lubricating oil can be supplied continuously and effectively for a long time. It is to provide a method for producing the obtained self-lubricating composition.

[Means for Solving Problems] That is, according to the present invention, 60 to 90% by weight of lubricating oil and 40 to 10% by weight of ultrahigh molecular weight polyethylene are mixed, the obtained mixture is heated and melted, and then the melted mixture. In the production of a self-lubricating composition which is cooled and solidified and impregnated with the above-mentioned lubricating oil and which exhibits the lubricity as a result of the impregnated lubricating oil being exuded, a mixture of the lubricating oil and the ultra high molecular weight polyethylene is mixed. Is a method for producing a self-lubricating composition under reduced pressure of 100 mmHg or less.

The lubricating oil used in the present invention is not particularly limited,
Conventional lubricating oils such as mineral oils and polyolefin-based oils can be used, but their traction coefficient is preferably measured using a Soda type cylindrical friction tester (Japanese Patent Publication No. 60-
43,391 gazette) value is 0.06 or more, preferably 0.07 or more, more preferably 0.08 or more. When the value of this traction coefficient becomes large, the value of the pressure viscosity index also tends to become large.When this pressure viscosity index is large, the lubrication performance indicated by the friction coefficient and the block wear amount against the load under the condition of low speed and high load. Is improved.

Specific examples of such a lubricating oil include, for example, mineral oil (Japanese Patent Publication No. 39-24,635), mixed oil of dialkyl aromatic hydrocarbon and dialuric alkane (Japanese Patent Publication No. 47-40,525), polymethylmethacrylate. (JP-B-48-31,828), pivalic acid monoester (JP-B-49-11,309), halogenated alkylnaphthalene (JP-B-49-1)
6,900, adamantanes (JP-B-48-42,067 and JP-B-48-42,068), alkylnaphthalenes (US Pat. No. 2,549,377), and the like, and naphthenes having a hydrogenated ring Dicyclohexylethane (Japanese Patent Publication No. 48-
29,715), dicyclohexyl propane (Japanese Patent Publication Sho 5
3-36,105), hydrogenated fused ring compounds (US Patent No.
Naphthenes with one or more saturated carbon-containing annular rings (US Pat. No. 3,440,894), Naphthenes with two or more saturated carbon-containing annular rings (US Pat. No. 3,925,217) ), A mixed oil of naphthene and paraffin (US Pat. No. 3,595,796 and US Pat. No. 3,595,797), xylene and / or mainly 1,1-diallylethane obtained by hydrogenating an alkylation reaction product of styrene and toluene. Containing compounds (Japanese Patent Application Laid-Open No. 55-43,108) and other naphthenic oils (Japanese Patent Application Laid-Open Nos. 55-40,726, 55-60,595 and
57-172,992, JP-A-57-172,993 and JP-A-58-122,9
94 gazette and Japanese Patent Publication No. 58-27,838 and Japanese Patent Publication No. 60-43,3
No. 91) and the like, and preferably a naphthenic oil having a hydrogenated ring such as hydrogenated benzyl biphenyl, hydrogenated dibenzyltoluene and hydrogenated alkylbenzene.

Further, in order to increase the value of the traction coefficient in this lubricating oil, the traction coefficient of cyclohexyl (meth) acrylate-based polymer etc. as described in JP-A-61-19697 is improved. Various additives required for general lubricating oils such as oxidation stability, rust prevention, viscosity index improvement, defoaming, corrosion resistance, and friction resistance can be added. sex,
In order to impart and improve rubber swelling property, for example, 2,
Alkylphenols such as 6-di-tert-butyl-p-cresol, antioxidants such as sulfur and phosphorus compounds such as zinc dialkyldithiophosphate, amines, esters, rust inhibitors such as metal salts, viscosity index improvers, Antifoaming agent such as silicone polymer,
Other anti-corrosion agents, anti-friction agents, rubber swelling agents and the like can be added.

The viscosity of the lubricating oil is not particularly limited, but the effect of the method of the present invention becomes remarkable when the viscosity (40
C.) is 100 cst. Or more. This 40 ℃ viscosity is 1
If it is lower than 00 cst., The air introduced into the raw material system at the time of mixing may escape without taking any measures, depending on the blending ratio with the ultra high molecular weight polyethylene and other additives. When the viscosity is 100 sct. Or more, the proportion of the air entrapped in the raw material system during mixing becomes high, and this tendency becomes more remarkable as the viscosity increases.

The ultrahigh molecular weight polyethylene used in the method of the present invention has an average molecular weight of about 1 × 10 ⁶ or more, preferably 2 × 10 6.
It is about ^{6 to} 5 × 10 ⁶ , and is produced by, for example, the Ziegler method (low pressure method) in which ethylene is liquid-phase polymerized under normal pressure using a Ziegler catalyst of a system consisting of trialkylaluminum and titanium chloride. You can Such ultra-high molecular weight polyethylene can be solidified and impregnated with the above-mentioned lubricating oil, and at the same time exhibits self-lubricating property, and when applied to various mechanical elements, etc., the impregnated lubricating oil oozes out. As a result, the lubricity can be exhibited.

Furthermore, when the self-lubricating composition is produced from the lubricating oil and the ultra-high molecular weight polyethylene, the mixing ratio of both is such that the lubricant retention amount and mechanical strength required for the self-lubricating composition produced are , 60 to 90% by weight of the lubricant, preferably 65 to 90% by weight, although it depends on hardness, dimensional stability and the like.
80% by weight, 40-1 ultra high molecular weight polyethylene
It is 0% by weight, preferably 35 to 20% by weight. If the content of the lubricating oil is less than 60% by weight, the mixture with the ultra-high molecular weight polyethylene will be in a rough state, and the fluidity will not be maintained, resulting in problems in moldability. If it exceeds 90% by weight, it will be solidified. The strength of the self-lubricating composition is insufficient.

Further, in the self-lubricating composition of the present invention, a solid lubricant such as molybdenum disulfide or Teflon or the like for the purpose of improving its lubricity, mechanical strength, hardness, dimensional stability, flame retardancy, stability, etc. Various additives such as glass fiber, diatomaceous earth, nylon powder, dyes, pigments, stabilizers, flame retardants and the like can be added within a range of usually 10% by weight or less. When adding such solid lubricants and other additives and they contain water,
It is necessary to dry it before adding it. If a solid lubricant containing water or other additives is added as it is, it may take a long time to melt, or part of it may remain unmelted, or it may hardly melt. The property, lubrication performance, etc. of the lubricating composition may become non-uniform, or molding may not be possible.

In the method of the present invention, it is necessary to mix the lubricating oil and the ultra high molecular weight polyethylene under a reduced pressure of 100 mmHg or less, preferably 60 mmHg or less, more preferably 40 mmHg or less. The degree of decompression required in the method of the present invention is ultimately determined by the content of the lubricating oil and its viscosity. When the content of the lubricating oil in the method of the present invention is about 60 to 90% by weight, the viscosity at 40 ° C is 23
If the viscosity is 0 cst. Or less, a reduced pressure of 60 mmHg or less is sufficient, if the viscosity at 40 ° C is 400 cst. Or less, the reduced pressure of 50 mmHg or less is sufficient, and if the viscosity at 40 ° C is 550 cst. Or less, a reduced pressure of 45 mmHg or less. Below, and for most lubricating oils with viscosities of up to about 1,200 cst. At 40 ° C., reduced pressures below 40 mm Hg are sufficient. Further, if the mixing temperature is raised, the viscosity is lowered, so that it is sufficient even under a reduced pressure which is higher than this, but it is disadvantageous to raise the temperature above the softening point of the ultrahigh molecular weight polyethylene. It is necessary to reduce the pressure to 100 mmHg or less. Further, the reduced pressure mixing time is 1 to 30 minutes, preferably 3 to 1
It is about 0 minutes.

In the case of producing a self-lubricating composition by the method of the present invention, for example, first, the lubricating oil and ultra-high molecular weight polyethylene and additives that are optionally added are weighed in a predetermined ratio,
Put the solid raw material in a stirrer and depressurize it to a predetermined degree, and when it is sufficiently depressurized, inject the liquid raw material while maintaining the depressurized state, and stir while heating at about 50 to 80 ° C if necessary. Mix evenly, bleach sufficiently, preferably until no bubbles are observed, then pour into a mold or the like of the desired shape and heat in the range 100-250 ° C, preferably 150-200 ° C. And then melted, usually 0.1 to 10 ° C./min., Preferably 0.5 to 5
Slowly cool at a cooling rate of ° C / min. To solidify. On this occasion,
By changing the mixing ratio of each of the above raw materials, jelly,
It can be formed into a semi-solid state, a solid state, or the like, and the amount of leaching of the lubricating oil can be adjusted by changing the blending amount of the lubricating oil or changing the cooling rate.

[Examples] Hereinafter, the self-lubricating composition of the present invention will be specifically described based on Examples.

Examples 1 to 17 Lubricating oils shown in Table 1 and ultrahigh molecular weight polyethylene having an average molecular weight of 3 × 10 ⁶ were weighed so that the blending ratio of the lubricating oils would be the values shown in Table 1, and stirring was possible under reduced pressure. Charge ultra-high molecular weight polyethylene into a stirrer, reduce the pressure to 40 mmHg or less, and then inject the lubricating oil while maintaining the reduced pressure state.
Stir under reduced pressure while heating to 0 ° C and mix well, put the resulting mixture in a 28 mmφ x 200 mm long test tube, and place it in an oven set to 170 ° C in advance. , This oven was heated and melted and the molten state at that time was observed. ○: The entire raw material system was completely melted. △: Part of the raw material system (particularly the central part) remained without melting. Also, x: Three-stage evaluation of almost no melting was performed, and in the case where the entire raw material system was completely melted, the time until completely melting was measured. The results are shown in Table 1.

After heating and melting in the oven for a predetermined time in this way, the oven is switched off and gradually cooled to room temperature at a cooling rate of 1 ° C / min. The thing was prepared.

Comparative Examples 1 to 17 Self-lubricating compositions were prepared in exactly the same manner as in Example 1 except that the raw material system was stirred in normal air without depressurization, and the molten state of the heat-melt cut was observed. At the same time, when the entire raw material system was completely melted, the time until it was completely melted was measured. The results are shown in Table 1.

Examples 18 to 26 Isopropylbiphenyl hydride having a viscosity of 6 at 40 ° C. (IP
BH), benzyl biphenyl hydride (BBPH) having a viscosity of 40 ° C. 41 or dibenzyltoluene hydride (DBTH) having a viscosity of 40 ° C. 63, and mineral oil having a viscosity of 40 ° C. 68 are mixed at a ratio shown in Table 2. Example 1 was used in the same manner as in each of the above Examples using 70% by weight of the obtained mixed oil and 30% by weight of the above-mentioned ultrahigh molecular weight polyethylene having an average molecular weight of 3 × 10 ^6.
8 to 26 self-lubricating compositions were prepared, and the molten state at that time was examined in the same manner as in Example 1 above. The results are shown in Table 2.

Comparative Examples 18 to 26 Self-lubricating compositions were prepared in exactly the same manner as in Examples 18 to 26 except that the raw material system was stirred in normal air without depressurization, and the molten state during heating and melting was performed. Was observed, and in the case where the entire raw material system was completely melted, the time until it was completely melted was measured. The results are shown in Table 2.

Examples 27 to 35 Isopropylbiphenyl hydride having a viscosity of 6 at 40 ° C. (IP
BH), benzyl biphenyl hydride (BBPH) having a viscosity of 40 ° C. 41 or dibenzyltoluene hydride (DBTH) having a viscosity of 40 ° C. 63, and poly-α-having a viscosity of 16 cst., 68 cst. Or 1,300 sct. An olefin (PAO) was mixed to prepare the following mixed oils, and 70% by weight of these mixed oils and 30% by weight of the ultrahigh molecular weight polyethylene having an average molecular weight of 3 × 10 ⁶ used in each of the above examples were used. Then, the self-lubricating compositions of Examples 27 to 35 were prepared in the same manner as in the above Examples, and the molten state at that time was examined. As a result, in all Examples, the entire raw material system was completely melted within 20 minutes.

Example No. Mixed oil composition Mix ratio 27 IPBH + PAO (16cst.) 7: 3 28 IPBH + PAO (68cst.) 5: 5 29 IPBH + PAO (1300cst.) 3: 7 30 BBDH + PAO (16cst.) 7: 3 31 BBDH + PAO (68cst.) 5: 5 32 BBDH + PAO (1300cst.) 3: 7 33 DBTH + PAO (16cst.) 7: 3 34 DBTH + PAO (68cst.) 5: 5 35 DBTH + PAO (1300cst.) 3: 7 Examples 36 to 38 The viscosity of 63 at 40 ° C. Dibenzyltoluene hydride (DBT
H) and viscosity at 40 ℃ 16sct., 68cst. Or 1,300s
ct. of poly-α-olefin (PAO) was mixed to obtain the mixed oil of Example 36 (DBTH + PAO (16 cst.), mixing ratio 7:
3}, mixed oil of Example 37 {DBTH + PAO (68cst.), Mixing ratio 5: 5} and mixed oil of Example 38 {DBTH + PAO (1300cs).
t.), a mixing ratio of 3: 7} was prepared, and 70% by weight of these mixed oils, 30% by weight of the above-mentioned ultrahigh molecular weight polyethylene having an average molecular weight of 3 × 10 ⁶ and molybdenum disulfide (MoS) as a solid lubricant were prepared. ₂ ) 5% by weight, and about 5% by weight of solid lubricant molybdenum disulfide before mixing at 100 ° C. for about 5%.
After preliminarily drying for 1 minute, the mixture was charged into a stirrer capable of stirring under reduced pressure together with ultra-high molecular weight polyethylene, and the self-lubricating compositions of Examples 36 to 38 were prepared by the same method as each of the above Examples, and the melting at that time was performed. I checked the condition. The results melted within 20 minutes in all the examples.

In addition, when the self-lubricating composition was prepared by the same method as each of the above-described examples without previously drying the solid lubricant molybdenum disulfide, the molten state was higher than that in the cases of Examples 36 to 38. It was bad, and in some cases it hardly melted. Further, the drying of molybdenum disulfide as a solid lubricant may be carried out by charging a stirring device capable of stirring under reduced pressure together with ultra high molecular weight polyethylene and then maintaining the stirring device at a predetermined temperature under a predetermined reduced pressure for a predetermined time. it can.

Reference Example 1 A self-lubricating composition having a size of 28 mmφ × 500 mm prepared according to Examples 6, 10 and 28 and Comparative Example 6 was pressed onto a ring with a force of 2 kgf, a Timken tester was used, and a load of 30 Lb was applied. , Ring speed 3
00 rpm., Test time: A lubrication performance test was conducted under conditions of no load for 3 minutes and a load of 10 minutes, and the friction coefficient and the block wear amount were investigated. The results are shown in Table 3.

The self-lubricating compositions of Examples 6, 10 and 28 were tested under the Timken tester under a load of 9.
When the block wear amount was examined under the conditions of 0 Lb and the ring rotation speed of 60 rpm. (Other conditions are the same), all of them were below the detection limit.

Furthermore, regarding the self-lubricating compositions of Examples 6, 10 and 28 and Comparative Examples 6 and 10, the amount of lubricating oil exuded at 80 ° C. and the time until the lubricating oil stopped exuding ((that is, exudation time ) And were measured.
Shown in the table.

In addition, Examples 6, 10 and 28 and Comparative Examples 6 and 10
In order to confirm the homogeneity of the self-lubricating composition, the hardness of each part was measured and the cut surface was observed. In each of the example products, the hardness change due to each part was small, and the cut surface was also uniform, but in the comparative example product, the hardness change due to each part was large, and the cut surface was heterogeneous.

Example 39 70% by weight of mineral oil having a viscosity of 460 cst. At 40 ° C. and an average molecular weight of 3 ×
When a self-lubricating composition was prepared in the same manner as in Example 1 using 10 ⁶ of ultrahigh molecular weight polyethylene 30% by weight, the cooling rate after heating and melting was changed to 27 mmφ × 5.
The self-lubricating lubricating compositions of Test Nos. 1 to 8 having a size of mm were prepared, and the cooling rate and the exudation amount of the lubricating oil from the prepared self-lubricating composition at 50 ° C. I investigated the relationship. The results are shown in Table 5.

Example 40 Mineral oil having a viscosity of 460 cst. At 40 ° C. and ultra-high molecular weight polyethylene having an average molecular weight of 3 × 10 ⁶ were mixed at a ratio of 80:20,
Mixing was performed at 60 ° C. for 5 minutes while changing the degree of vacuum. The results of observing the mixed solution are shown in Table 6.

[Effects of the Invention] According to the method of the present invention, it is possible to prevent air from being mixed when the lubricating oil and the ultra high molecular weight polyethylene are mixed,
As a result, it is possible to shorten the melting time at the time of heating and melting and to achieve complete melting, and the properties and lubricating performance of the self-lubricating composition after solidification are uniform and continuous and effective over a long period of time. A self-lubricating composition capable of supplying a lubricating oil can be produced. Further, since it is possible to achieve complete melting at the time of heating and melting, various kinds of lubricating oil can be used, and a self-lubricating composition used under conditions such as low speed and high load range can be easily prepared. It can be manufactured.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 107: 04) C10N 20:04 30:06 40:02 40:04 70:00 (72) Invention Person Masao Ando 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Inside the Nagoya Steel Works (72) Inventor Harunobu Kato 2112-30 Kamigo-cho, Sakae-ku, Yokohama-shi, Kanagawa 72 Inventor Eisaku Matsumoto Aichi 4-8-12-117 Gokisho, Showa-ku, Nagoya (72) Inventor Teruyuki Honda 2-9-10 Takashimadaira, Itabashi-ku, Tokyo

Claims (2)

[Claims] 1. Lubricating oil 60 to 90% by weight and ultra high molecular weight polyethylene 40 to 10% by weight are mixed, the resulting mixture is heated and melted, and then the molten mixture is cooled to solidify to obtain the above lubricating oil. In producing a self-lubricating composition that exhibits lubricity as a result of impregnation and exudation of the impregnated lubricating oil, mixing of the lubricating oil and ultra high molecular weight polyethylene is performed under a reduced pressure of 100 mmHg or less. And a method for producing a self-lubricating composition. 2. The method for producing a self-lubricating composition according to claim 1, wherein the molten mixture is cooled gradually from its melting temperature to its use temperature at a cooling rate of 0.1 to 10 ° C./min.