JPH0322920B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention provides lubricity to a rotating shaft portion such as a rotary variable resistor (volume) or dial of an electronic component switch, various audio devices, etc. to smooth its rotation, and reduces rotational resistance in a bearing. The present invention relates to a silicone grease that appropriately utilizes (torque) to give a sense of luxury to the hands of the person who operates it. [Technical background of the invention and its problems] Greases conventionally used for the purpose of imparting luxury and lubricity to the rotating shafts of rotating volumes of electronic parts and audio equipment include, for example, polyisobutene and thickeners. Those consisting of polyisobutene, mineral oil and a thickening agent are generally known. However, these greases have the disadvantage that if they are left in a high temperature area of 100℃ or higher for a long time, the viscosity of the polyisobutene decreases rapidly and it flows out of the applied area, or the polyisobutene begins to decompose and the grease itself becomes hard. . And vice versa,
It has the disadvantage that it solidifies in the low temperature range of around 0° C., making it difficult to operate the volume, or in extreme cases, making it impossible to rotate it. Various proposals have been made in the past as attempts to improve this type of drawback, for example,
No. 66552 and Japanese Unexamined Patent Publication No. 53-43171 disclose inventions relating to silicone greases having appropriate adhesiveness. That is, the above-mentioned JP-A-50-66552 discloses polydiorganosiloxane and R ₃ SiO _1/2 units,
A silicone grease comprising an organosiloxane composition comprising R ₂ SiO units and SiO ₂ units and a thickener is also disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 53-43171.
A silicone grease comprising a polydiorganosiloxane and an organosiloxane composition comprising R ₃ SiO _1/2 units, RSiO _3/2 units and SiO ₂ units and a thickener is disclosed (wherein R is an alkyl group, an alkenyl group). group, aryl group). However, these silicone greases
When a rotating polyurethane is operated for a long period of time, the torque value decreases, and eventually the rotating shaft becomes damaged and stops moving (so-called seizure). Furthermore, JP-A-53-79162 discloses that polybutene and polyorganosiloxane have improved compatibility with polyisobutene by introducing a long-chain alkyl group as an organic group bonded to the silicon atom of polyorganosiloxane. A grease comprising a thickener has been disclosed, but this grease has a drawback of poor low temperature properties due to the long chain alkyl group. [Purpose of the Invention] As a result of intensive research aimed at solving these conventional drawbacks, the present inventors have discovered that alkyltris(trialkoxysiloxy)silane has good compatibility with both polybutene and polyorganosiloxane. The above drawbacks can be overcome by blending this alkyltris(trialkoxysiloxy)silane with polybutene or a mixture of polybutene and polyorganosiloxane to form a base composition, and further blending a thickener with this base composition. I found out that it can be done. The present invention was made based on this knowledge,
The purpose of the present invention is to provide a silicone grease that has good tackiness over a wide range from low-temperature regions to high-temperature regions, has little change in torque value when used for a long time, and has a long operating life. [Summary of the Invention] That is, the grease of the present invention comprises (A) (a) polybutene or polybutene and the general formula [R ¹ _a SiO _(4-a)/2 ] _o (wherein R ¹ is a carbon number of 1 to 12 a monovalent group selected from the group consisting of an alkyl group and a substituted or unsubstituted aryl group, a is a number from 1.9 to 2.7, and n is a positive number) 50 to 95% by weight of a composition consisting of (in an amount of 50% by weight or less based on the amount), and (b) general formula
5 to 50% by weight of alkyltris(trialkoxysiloxy)silane represented by R ² Si[OSi(OR ³ ) ₃ ] ₃ (in the formula, R ² and R ³ each represent an alkyl group having 1 to 12 carbon atoms) It is characterized in that 1 to 50 parts by weight of a thickener (B) is added to 100 parts by weight of a base composition consisting of. (A) which forms the main component of the base composition in the present invention
Polybutene, which is the main component or the entire component (a), is a viscous substance obtained by polymerizing isobutylene, and has the general formula (In the formula, m represents a positive integer.) Commercially available products with a wide range of viscosities from low to high viscosity depending on the degree of polymerization can be used. In the present invention, it is preferable to use one having a viscosity at 25° C. of 10,000 to 1,000,000 cSt. Viscosity at 25℃ is 10000cSt
If the viscosity is less than 1,000,000 cSt, it is undesirable because the adhesive force will be weak and it will not be possible to obtain a grease with appropriate viscous resistance.On the other hand, if the viscosity exceeds 1,000,000 cSt, it will be difficult to mix with polyorganosiloxane, alkyltris(trialkoxysiloxy)silane, etc. Moreover, the viscous resistance of the resulting grease becomes too large, which is not preferable. In addition, the polyorganosiloxane that is mixed and used as component (a) as required has the general formula [R ¹ _a
SiO _(4-a)/2 ] _o (wherein,
R ¹ represents a monovalent group selected from the group consisting of an alkyl group having 1 to 12 carbon atoms and a substituted or unsubstituted aryl group, a represents a number from 1.9 to 2.7, and n represents an integer). In the above general formula, if the number of carbon atoms in R ¹ exceeds 12, handling becomes inconvenient and thermal stability decreases, which is not preferable. Further, R ¹ may be the same or different. R ¹ is a methyl group,
Ethyl group, propyl group, butyl group, pentyl group,
Examples include hexyl group, octyl group, dodecyl group, phenyl group, and chlorinated phenyl group, but methyl group is preferred from the viewpoint of ease of synthesis and heat resistance. Furthermore, in the above general formula, if a is smaller than 1.9, the grease will become hard, and if it is larger than 2.7, it will not be possible to obtain an appropriate viscosity, so both are not preferred. Furthermore, it is desirable that the polyorganosiloxane represented by the above general formula have a viscosity of 100 to 500000 cSt at a temperature of 25°C. Therefore, n, which represents the degree of polymerization, is the number necessary to obtain this viscosity. This is desirable. If the viscosity of the above polyorganosiloxane is less than 100 cSt at 25°C, the volatility of the polyorganosiloxane itself is high, and the resulting base composition not only flows easily, but also It is not preferable to mix it with other substances, as it becomes easy to separate. On the other hand, if the viscosity exceeds 500,000 cSt, synthesis becomes difficult and workability when mixing with polybutene, alkyltris(trialkoxysiloxy)silane, etc. is significantly reduced, which is not preferable. The blending amount of component (A) in the present invention is component (A) consisting of component (A) and component (B) described below, that is, 50 to 95% by weight of the entire base composition, and the total amount of component (A). It is desirable that the blending ratio of polyorganosiloxane is 50% by weight or less. If the blending ratio of polyorganosiloxane to the entire component (a) exceeds 50% by weight, it is not preferable because it will not be possible to obtain a grease that exhibits appropriate viscous resistance and is suitable for bearings such as rotating volumes. The general formula of component (b) in the present invention is R ² Si[OSi
(OR ³ ) ₃ ] The alkyltris(trialkoxysiloxy)silane represented by ₃ uniformly mixes the polybutene and polyorganosiloxane as the component (a) without deteriorating the low-temperature properties. When used alone, it has the effect of improving its low temperature characteristics. R ² and R ³ in the general formula are each an alkyl group having 1 to 12 carbon atoms, and examples thereof include methyl group, ethyl group, propyl group, butyl group, isobutyl group, pentyl group, and isopentyl group. , from the viewpoint of ease of synthesis and compatibility with the above-mentioned component (a), it is desirable that R ² is a methyl group,
Furthermore, from the viewpoint of hydrolysis resistance, R ³ is preferably an isobutyl group. The blending ratio of this component (b) is preferably 5 to 50% by weight of the total amount of the base composition consisting of this component and the component (a). If the blending ratio of component (B) is less than 5% by weight of the entire base composition, the polybutene and polyorganosiloxane of component (B), which have poor compatibility, cannot be uniformly mixed, and the resulting grease On the other hand, if it exceeds 50% by weight, the resulting grease will not only become too soft and have no suitable viscous resistance, but also flow out when applied to the bearings of rotating shafts, so both are preferable. do not have. The thickener (B) in the present invention is one that imparts an appropriate consistency to the grease, and includes fine silica powder, metal soap, carbon, graphite, talc, organically modified bentonite, urea resin, polytetrafluoroethylene, etc. is exemplified. The thickener (B) is blended in an amount of 1 to 50 parts by weight per 100 parts by weight of component (A). If the amount of component (B) is less than 1 part by weight, a suitable consistency will not be obtained and the product will become fluid, which may cause run-off, layer separation, etc. when applied to bearings, etc., which is not preferable. In addition, if it exceeds 50 parts by weight, it will become too hard, making it difficult to apply to the rotating shaft, and the lubricity will decrease.
Moreover, it is undesirable because it causes more friction on the rotating shaft than necessary, causing seizure. The silicone grease of the present invention can be easily produced by mixing the above components by conventional means, or by stirring and mixing them under heating at a predetermined temperature, and after cooling, kneading them uniformly using three rolls such as paint rolls. can be obtained. If necessary, various additives such as antioxidants such as amine compounds and selenium compounds, and extreme pressure additives such as halogen compounds and phosphoric acid compounds may be added to the extent that the effects of the present invention are not impaired. can do. [Examples of the invention] Next, examples of the invention will be described. Example 1 Polybutene (manufactured by NOF Corporation, Nitsusan Polybutene PB2000SH) 75 parts by weight, viscosity at 25°C
20 parts by weight of 10,000 cSt polydimethylsiloxane, methyltris(triisobutoxysiloxy)silane (manufactured by Chitsuso Corporation, silicate cluster SC102) 5
parts by weight, and 10 parts by weight of treated finely powdered silica powder,
Stir and mix at 150℃, and after cooling, knead uniformly using a paint roll to obtain grease with a consistency of 258 (S-
1) was obtained. Example 2 65 parts by weight of the same polybutene used in Example 1,
30 parts by weight of polydimethylsiloxane having a viscosity of 100,000 cSt at 25°C, 15 parts by weight of methyltris(triisobutoxysiloxy)silane and 10 parts by weight of finely powdered silica powder were mixed in the same manner as in Example 1,
Grease (S-2) with a consistency of 271 was obtained. Example 3 75 parts by weight of the polybutene used in Example 1, 20 parts by weight of polymethylphenylsiloxane with a viscosity of 2000 cSt at 25°C, 5 parts by weight of methyltris(triisobutoxysiloxy)silane, and finely powdered polytetrafluoroethylene powder 15 parts by weight were mixed in the same manner as in Example 1 to obtain a grease (S-3) with a consistency of 312. Example 4 90 parts by weight of polybutene, 10 parts by weight of methyltris(triisobutoxysiloxy)silane, and 10 parts by weight of finely powdered silica powder used in Example 1 were added to Example 1.
Mix in the same manner as above and add 320 consistency grease (S-
4) was obtained. Example 5 90 parts by weight of polybutene, 10 parts by weight of methyltris(triisobutoxysiloxy)silane and 8 parts by weight of aluminum stearate used in Example 1 were added.
The mixture was heated and mixed at 185° C. for 1 hour, cooled, and then uniformly kneaded using a paint roll to obtain a grease (S-5) with a consistency of 240. Example 6 70 parts by weight of the polybutene used in Example 1, the following molecular formula 20 parts by weight of polyorganosiloxane represented by
10 parts by weight of methyltris(triisobutoxysiloxy)silane, 5 parts by weight of finely powdered silica powder, and 10 parts by weight of finely powdered polytetrafluoroethylene powder were mixed in the same manner as in Example 1, and a grease with a consistency of 322 (S-6 )
I got it. Example 7 70 parts by weight of polybutene used in Example 1, the following molecular formula 20 parts by weight of polyorganosiloxane represented by
10 parts by weight of methyltris(triisobutoxysiloxy)silane, 5 parts by weight of finely powdered silica powder, and 10 parts by weight of finely powdered polytetrafluoroethylene powder were mixed in the same manner as in Example 1, and a grease with a consistency of 343 (S-7) was mixed. )
I got it. Comparative Example 1 To 100 parts by weight of the polybutene used in Example 1, 5 parts by weight of finely powdered silica powder and 10 parts by weight of finely powdered polytetrafluoroethylene powder were added and mixed in the same manner as in Example 1 to obtain a mixture with a consistency of 200%. Grease (R-1) was obtained. Comparative example 2 Polybutene 100 with a viscosity of 10000 cSt at 25°C
5 parts by weight of finely powdered silica powder and 10 parts by weight of finely powdered polytetrafluoroethylene powder were added to the parts by weight, and mixed in the same manner as in Example 1 to obtain a grease (R-2) with a consistency of 237.
I got it. The following experiments were conducted to examine the characteristics of each grease thus obtained. A shaft (made of aluminum) with a diameter of 4.95 mm and a length of 13.5 mm was installed on a bearing (made of brass) with a diameter of 5 mm and a length of 11.8 mm. After applying each of the obtained greases, rotate at a torque rotation speed of 20 rpm, and calculate the torque value after 60 seconds (initial) and 30 minutes and -10
The torque values at -30°C and -30°C were measured. The measurement results are shown in the table below.

[Table] [Effects of the Invention] As is clear from the above examples, the grease of the present invention has extremely small changes in consistency and torque value over a wide temperature range, has a long operating life, and is suitable for use in stereo, It can be widely used in various rotating volumes of electrical products such as radios and televisions, and other acoustic communication devices.

Claims (1)

[Claims] 1 (A) (a) Polybutene or polybutene with the general formula [R ¹ _a SiO _(4-a)/2 ] _o (wherein R ¹ is an alkyl group having 1 to 12 carbon atoms and a substituted or a monovalent group selected from the group consisting of unsubstituted aryl groups, a is 1.9 to
2.7, n is a positive number) (however, the amount is not more than 50% by weight based on the total amount with polybutene); and (b) general Formula R ² Si [OSi
(OR ³ ) ₃ ] ₃ (In the formula, R ² and R ³ each have a carbon number of 1 to
Alkyltris(trialkoxysiloxy)silanes 5 to 12 (representing an alkyl group)
A grease characterized in that (B) 1 to 50 parts by weight of a thickener is added to 100 parts by weight of a base composition consisting of 50% by weight. 2 R ¹ of the general formula of the polyorganosiloxane (a)
The grease according to claim 1, wherein is a methyl group. 3 The viscosity of the polybutene in (a) at 25℃ is 10000
The grease according to claim 1 or 2, wherein the grease has a temperature of 1,000,000 cSt. 4. Claim 1, wherein the polyorganosiloxane of (a) has a viscosity of 100 to 500,000 cSt at 25°C.
The grease described in any one of Items 1 to 3. 5. The grease according to any one of claims 1 to 4, wherein R ² in the general formula of the alkyltris(trialkoxysiloxy)silane (b) is a methyl group. 6. The grease according to any one of claims 1 to 4, wherein R ³ in the general formula of the alkyltris(trialkoxysiloxy)silane (b) is an isobutyl group.