JPH04164995A - Silicone grease composition - Google Patents

Abstract

PURPOSE:To impart a silicone grease composition with improved rustproofness and lubricity by compounding a specific polyorganosiloxane, a thickener, a fine fluororesin powder and a specific thiol. CONSTITUTION:A silicone grease composition is obtained by compounding 100 pts.wt. polyorganosiloxane represented by an average composition formula of (R<1>)aSiO(4-a)/2 (wherein R<1> represents an (un)substituted monovalent hydrocarbon group; and a represents a number of 1.9 to 2.7, which means an average value); 0.01-50 pts.wt. thickener; 0.01100 pts.wt. fine fluororesin powder; and 0.01-3 pts.wt. thiol selected among compounds represented by R<2>SH (wherein R<2> represents a 10-22C (un)saturated monovalent hydrocarbon group) and compounds represented by HSR<3>SH (wherein R<3> represents a 3-16C (un)saturated divalent hydrocarbon group).

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a lubricating silicone grease with excellent anti-corrosion effects, and more particularly, to a lubricating and sealing material for key cylinders of automobiles, motorcycles, etc. The present invention relates to a silicone grease composition useful as a silicone grease composition.

(Prior art) Mineral oil-based lubricating grease has traditionally been used as a lubricating and sealing material for key cylinders;
Exposure to low temperatures below and high temperatures above +80℃, -40℃
Below this, the grease will harden and the key will no longer work.
At high temperatures, there were problems such as grease flowing out. Furthermore, general silicone-based grease does not have a rust-preventing effect, and there are problems such as corrosion occurring inside the key cylinder and the key cylinder becoming inoperable. Even with silicone grease that has a rust-preventing effect, there is a problem that the metal is heavily worn and the operability is poor due to the thickening caused by the addition of silica powder.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above problems and provide a silicone grease composition that has both high antirust effect and lubricity.

[Structure of the Invention] (Means for Solving the Problem) As a result of intensive studies to achieve the above object, the present inventors have found that thiol is used as a rust preventive agent and fluororesin fine powder is used as a lubricant. A silicone grease composition with excellent antirust effect and excellent lubricity was discovered by blending the above ingredients, and the present invention was completed.

The present invention comprises the following components (A), (B), (C) and (D).
) and a silicone grease composition.

(A) average composition formula % formula % (wherein R1 represents a substituted or unsubstituted monovalent hydrocarbon group, a is a number from 1.9 to 2.7 and represents the average value) 100 parts by weight of polyorganosiloxane, (B) 0.01 to 50 parts by weight of thickener.

(C) 0.01-100 parts by weight of fluororesin fine powder, (D) Formula R”SH (wherein, R2 is a saturated or unsaturated 1 having 10 to 22 carbon atoms)
represents a valent hydrocarbon group) and a compound represented by the formula H5R"SH (wherein R3 represents a saturated or unsaturated divalent hydrocarbon group having 3 to 16 carbon atoms) thiol
0.01-3 parts by weight.

The organic group R1 bonded to the silicon atom of the polyorganosiloxane of component (A) represented by the average compositional formula % formula % which forms the main component of the present invention includes methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, Alkyl groups having 1 to 30 carbon atoms such as dodecyl, hexadecyl, octadecyl, and eicosyl; aryl groups such as phenyl; aralkyl groups such as β-phenylethyl and B-phenylpropyl; and chloromethyl, 3.3.3
- Monovalent substituted hydrocarbon groups such as trifluoropropyl and chlorinated phenyl are exemplified, and these R1s may be the same or two or more different types, and the alkyl group has more than 30 carbon atoms. and its handling becomes inconvenient,
Thermal stability is also reduced, making it undesirable for use.
Among these organic groups, 50% or more are preferably methyl groups from the viewpoint of ease of synthesis and heat resistance.

In the formula, a is a number from 1.9 to 2.7 and represents the average value per silicon atom in the polymer molecule. l
If it is smaller than 9, the grease is hard and cannot be used; 2.
If it is larger than 7, an appropriate viscosity range cannot be obtained. That is, it is desirable that these polyorganosiloxanes have a viscosity of 10 to 100.0 OOcSt at a temperature of 25°C. If it is less than 10 cSt, the volatility of the polyorganosiloxane is high, and the resulting grease flows easily.
It may leak out from the key cylinder and cause malfunction.

Moreover, when it exceeds 100.000 cSt, the viscous resistance becomes large and the force required to operate the key cylinder becomes large. Such polyorganosiloxanes may be a mixture of different viscosities and may have a linear or branched molecular shape,
Or it may be a mixture thereof.

The component (B) thickener used in the present invention is the component (A
) gives appropriate consistency to polyorganosiloxane, and contains fine silica powder, metal soap, carbon, graphite, talc, organically modified bentonite, urea resin,
Examples include molybdenum disulfide. These thickeners must be used in an amount of 0.01 to 50 parts by weight per 100 parts by weight of component (A). If it is less than 0.01 part by weight, it will not be possible to obtain an appropriate consistency and will flow easily, causing outflow, layer separation, etc. when applied inside a key cylinder, making it unsuitable. Moreover, if it exceeds 50 parts by weight, the consistency will be low and it will become very hard, which will not only make it difficult to apply it to a part of the key ring, but also, for example, fine silica powder will be highly abrasive and will impair lubricity. Furthermore, although metal soap has excellent lubricity, it has a good affinity with water, which can easily cause corrosion.

Among these thickeners, fine silica powder is particularly effective.

Examples of fine silica powder include fumed silica, precipitated silica, and silica aerogel.If the amount is too large, the lubrication life will be significantly impaired, but if the appropriate amount is selected, the particle size will be from several m/I to several units. Because of its small size, it is effective to obtain a suitable consistency with a small amount of blending. It is generally preferable to use fine silica powder in a range of 0.1 to 10 parts by weight. These silicas may be surface-treated with organosilane, polyorganosiloxane, organosilazane, or the like.

Examples of the fluororesin fine powder of component (C) used in the present invention include tetrafluoroethylene resin, tetrafluoroethidine-hexafluoropropylene copolymer, trifluorochloride ethylene resin, etc., and the particle size is 0. 05-50P fine powder is preferred
If the particle size is less than 0.05P, it is difficult to obtain industrially, and if it exceeds 50P, it becomes difficult to penetrate into the metal-to-metal contact area in the key cylinder, resulting in poor operability, which is not preferable.

The amount of fluororesin fine powder added is 0.01 to 100 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of component (A).
It is 0 parts by weight. If it is less than 0.01 parts by weight, not only will it not be possible to obtain an appropriate consistency, but the workability will be poor. If the amount exceeds 50 parts by weight, the consistency of the grease will be low and it will be very hard, making it difficult to apply the grease.

Among the thiols of component (D) used in the present invention, the thiol (mercaptan) represented by the general formula R"SH is R2
is a hydrocarbon group having 10 to 22 carbon atoms, preferably 18 to 22 carbon atoms. If the number of carbon atoms is less than 10, the vapor pressure will be high and it will easily volatilize at room temperature, making it unsuitable. Silicone greases using mercaptans with carbon numbers of 24 or more have poor rust prevention effects due to poor adsorption of mercaptans to metals. .

Examples of mercaptans that meet these conditions include decyl mercaptan, dodecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan, hexadecyl mercaptan, octadecyl mercaptan,
Examples include isooctadecylmercaptan, cis-9-octadecenylmercaptan, eicosylmercaptan, and tocosylmercaptan. Note that mercaptans having an odd number of carbon atoms may be difficult to obtain industrially.

In addition, the dithiol represented by the general formula H5R"SH is R3
is a divalent hydrocarbon group having 3 to 16 carbon atoms. If the number of carbon atoms is less than 3, the vapor pressure is high and it easily evaporates at room temperature, making it unsuitable. If the number of carbon atoms exceeds 16, the adsorption to metals is poor, resulting in a decrease in rust prevention effect, so it is unsuitable. , examples of these organodithiols include 1
, 3-drimethylene dithiol, 1,4-tetramethylene dithiol, 1,5-pentamethylene dithiol, 1
．． 6-hexamethylene dithiol, 1.8-octamethylene dithiol, 1.10-decamethylene dithiol,
Examples include 1.12-dodecamethylene dithiol and 1.14-tetradecamethylene dithiol.

The amount of component (D) added is 0.01 to 3 parts by weight, preferably 0.1 to 3 parts by weight, per 100 parts by weight of component (A).
The range is 1.0 parts by weight. Addition ・If the amount is less than 0.01 part by weight, the rust prevention effect will not be sufficiently observed;
Even if it exceeds the limit, no further effect can be achieved.

The silicone grease composition of the present invention comprises (A) to (D)
It is obtained by uniformly mixing predetermined amounts of the four components, but a thixoating agent, an antioxidant, etc. may be added.

However, some of these additives can significantly inhibit the rust-preventing effect, so care must be taken.

Note that these components may be mixed by heat treatment or vacuum mixing as necessary, and then mixed well using a three-roll or colloid mill to form a grease.

The silicone grease composition of the present invention thus obtained has the heat resistance originally possessed by silicone oil,
It has cold resistance, water repellency, and sealing properties, and the addition of rust preventive agent and fluororesin fine powder makes it excellent in rust preventive effect and lubricity, making it a lubricating and sealing agent for key cylinders of automobiles, motorcycles, etc. It is particularly useful as a

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

In addition, parts in Examples are parts by weight, and viscosity is a value measured at 25°C.

Examples 1 to 6 and Comparative Examples 1 to 5 To 100 parts of various polyorganosiloxanes shown in Table 1 having a viscosity of 100 to 1000 cSt, silica powder and Teflon (trade name 2) of the type and amount shown in Table 1 were added. Tetrafluoroethylene resin) fine powder and mercaptan are mixed together and kneaded using three rolls to produce silicone grease having the consistency shown in Table 1.A corrosion test and a lubrication test are conducted, and the results are reported in Table 1. It is shown in Table 1.

The corrosion test was conducted using JISC1009 copper plate (IX20
A sample was applied to about half of the sample (x80 mm), immersed in 5% saline for 1 hour, and then left in an atmosphere of 70° C./95% RH for 168 hours to observe the presence or absence of corrosion.

In the lubricity test, an aluminum ring and a disk were used, and the ring was rotated at 50 rpm with a pressing force of 10 kgf, and the abrasion properties were examined after about 10 minutes.

[Effects of the Invention] As shown in Table 1, all of the compositions of the present invention exhibited good rust prevention effects and lubricity. However, it was confirmed that the antirust effect and lubricity were poor in both the comparative examples of the system without the addition of mercaptan and the system without the addition of fine Teflon powder.

Claims (1)

[Scope of Claims] A silicone grease composition comprising the following components (A), (B), (C) and (D) and composition. (A) Average compositional formula (R^1)_aSiO_(_4_-_a_)_/_2(
100 parts by weight of a polyorganosiloxane represented by B) 0.01 to 50 parts by weight of thickener, (C) 0.01 to 100 parts by weight of fluororesin fine powder, (D) Formula R^2SH (wherein R^2 is a saturated carbon number of 10 to 22) or represents an unsaturated monovalent hydrocarbon group) and the formula HSR^3SH (wherein R^3 is a saturated or unsaturated 2 group having 3 to 16 carbon atoms)
A thiol selected from the group consisting of the compounds represented by (representing a valent hydrocarbon group)
01-3 parts by weight.