KR20090043003A - Silicone grease with high cold cohesion - Google Patents

Abstract

At least one oily diorganopolysiloxane polymer, 10 to 30% by weight of organometallic soap (s) and 2 to 10% by weight of non-ectotoxic additive (s), such as non-chlorinated paraffins. Silicone grease with high cohesion, characterized in that. Treatments and / or protective agents in the field of mobile grease mobile components of the grease, particularly at low temperatures, having good cohesion and, in particular, avoiding skating phenomena between components involved in the drive device, especially at low temperatures. And / or as lubricant.

Silicone Grease, Cohesion, Soap, Automotive, Drive Unit

Description

Silicone grease with high low temperature cohesion {SILICONE GREASE WITH HIGH COLD COHESION}

The present invention relates to organometallic-soap-based silicone greases having high cohesion, especially at low temperatures. The invention also relates to a process for producing said grease and to its use, in particular in the automotive industry.

It is known that in certain applications in the automotive industry it is necessary to apply highly cohesive grease, especially at low temperatures:

First, a skating phenomenon between the mobile metal components related to the drive device, and

Secondly, the possibility of grease loss by flowing out of the housing for applications where the grease is in an unconfined chamber.

Examples of drive devices that may be mentioned are: automotive clutch cables, gearboxes or starters.

In order to avoid the above-mentioned phenomena through improving the low temperature threshold, the behavior in the mechanical test to reproduce the skating phenomenon between the components involved in the drive system and the flow threshold value of the grease (or The correlation between the critical stress) has become possible in the art; The flow threshold can be measured in a manner known per se, for example using a stress control rheometer capable of conditioning the grease at the temperature selected for the test (in this case -40 ° C).

An essential object of the present invention is to propose a silicone grease that can have a high flow threshold of greater than 600 Pa at -40 ° C.

Another object is to leach (or runoff) the standard properties of grease, in particular its consistency at ambient temperatures of 23 ° C., low volatiles content and at high temperatures, ie at temperatures in the range from 100 ° C. to 170 ° C. It is to propose a silicone grease that can have such a high low temperature flow threshold without compromising good resistance to bleeding).

Another object is to propose silicone greases which can be prepared via methods known to those skilled in the art and under economical cost conditions.

One object of the present invention is therefore a high cohesive silicone grease containing the following paraffins which are non-halogenated, in particular non-chlorinated, essentially petroleum distillation-based, Grease, characterized by a linear hydrocarbon, selected from the group consisting of C ₁₀ -C ₁₃ short chain paraffins, C ₁₄ -C ₁₇ heavy chain paraffins and C ₁₈ -C ₅₀ long chain paraffins:

At least one oily diorganopolysiloxane polymer,

10-30% by weight of at least one organometallic soap, relative to the weight of silicon grease, and

At least one paraffin from 1 to 10% by weight.

The greases according to the invention, even at -40 ° C, have high flow thresholds in excess of 1000 Pa, while at the same time providing the desired technical properties in terms of penetration, volatile compound content and leaching behavior, for example. to provide.

The oily diorganopolysiloxane polymer which is a basic component of the grease corresponds to the following general formula:

(R) ₃ SiO [Si (R) ₂ O] _n Si (R) ₃

{Wherein symbol R may be the same or different and represents a hydrocarbon-based radical having 13 or less carbon atoms without aliphatic unsaturation, and symbol n represents any number in the range from 30 to 1500}.

These linear polymers thus consist essentially of a series of siloxy units of the formula (R) ₂ SiO _2/2 , in addition to the terminal units; However, small amounts of other siloxy units, such as units of the formula SiO _4/2 (“Q” units) and (R) SiO _3/2 (“T” units), may be added to (R) ₂ SiO _2/2 units (“ Existing at a rate of 1% or less relative to the number of D ″ units) is not excluded.

The hydrocarbon-based radical represented by the symbol R is selected from:

Alkyl radicals having 1 to 13 carbon atoms, in particular methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, octyl, decyl and dodecyl radicals;

Aromatic radicals having 6 to 10 carbon atoms with only one benzene nucleus, in particular radicals which may have one or more substituents including chlorine, for example phenyl, tolyl, xylyl, ethylphenyl, cumenyl and butylphenyl radicals.

According to one preferred embodiment, at least 45% of the hydrocarbon-based radicals R are alkyl radicals. These diorganopolysiloxane polymers are oily liquids having a viscosity (depending on the nature of the radicals R and the value of n) substantially in the range of 100 mPa · s to 500,000 mPa · s at 25 ° C. They are mainly produced industrially by silicon manufacturers; Furthermore, their preparation is presented in the chemical literature, for example in French patents 978 058, 1 025 150 and 1 108 964.

As a guide to the polymers that can be used, mention may be made of those represented by the following formula:

The values of ni and n'i (i = 1-7), respectively, vary within a given range such that the number of methyl radicals in each polymer molecule, as already indicated, of all radicals attached to the silicon atoms of these polymers It should be at least 45% by number.

The oily diorganopolysiloxane polymers preferably used alone or as a mixture are those represented by the formulas (III) to (VII).

In addition to the oily diorganopolysiloxane polymer, the silicone grease according to the present invention contains an organometallic soap as a gelling agent.

The gelling agent used to form the grease may be a fatty acid soap. The saponifiable material may be derived from higher fatty acids having 10 to 32 carbon atoms which may be hydroxylated or non-hydroxylated and may be saturated or unsaturated.

Soaps of non-hydroxylated fatty acids are preferably used, in particular the following: capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lig Noseric acid, myristoleic acid, palmitoleic acid, oleic acid, linoleic acid and erucic acid; Fatty acids, and / or their glycerides, such as lard oil, bee oil, rapeseed oil, palm oil, menhaden oil, or optionally from cottonseed oil, palm oil and hardened fish oil, or Herring oil; Acids derived from oxidation of liquid petroleum and waxes; Resinic acid; Heavy oil acid; Abietic acid; Naphthenic acid or sulfonic acid.

The saponifying agent used to make the soap is a metal Li, Na, K, Cs, Mg, Ca, Sr, Cd, Zn, Pb or Co compound and preferably an oxide of one of the alkali and alkaline earth metals mentioned above, It may be hydroxide or carbonate. Mixtures of soaps may also be used, and these soaps may be prepared in situ or prepared in advance to form the grease.

Specific examples of soaps used alone or as a mixture are: lithium soaps of stearic acid; Lithium soaps of cured fish oil fatty acids; Sodium soap of stearic acid; Sodium soap of oleic acid; Potassium soap of oleic acid; Calcium soap of stearic acid; Barium soap of stearic acid; Barium soap of stearic and oleic acid mixtures; Stearic acid lithium and sodium complex soap.

Particularly suitable soaps, used alone or as a mixture, are lithium soaps of stearic acid and lithium and sodium complex soaps of stearic acid.

The soap content of the greases according to the invention corresponds to 10 to 30% by weight and, according to a preferred embodiment, to 15 to 25% by weight.

Furthermore, auxiliary additives for the purpose of facilitating the preparation of the grease (better charge dissipation, reduction of blending time) and / or to enhance their internal cohesion and / or to provide coloration of the oily dior Incorporation into organopolysiloxane polymers and organometallic soaps. Additives that may be mentioned as guides include: polyalkylene glycols; Boric acid and alkyl borate; Pentaerythritol; Hydroxylated diorganopolysiloxane oils having a low viscosity in the range of 10 to 500 mPa · s at 25 ° C .; Coloring pigments. When these additives are used, their total introduction amount is generally in the range of 1 to 8% by weight relative to the weight of the grease.

Non-chlorinated paraffins included in the construction of the silicone greases according to the invention can be selected from many of the described and commercially available organic compounds of this type.

It is known that these compounds are liquid under atmospheric pressure and at room temperature (23 ° C.); They generally have a viscosity in the range of 5 to 1000 mPa · s, preferably in the range of 5 to 500 mPa · s.

Applicants have found that under the conditions of the present invention, the non-chlorinated paraffins used are preferably non-chlorinated C ₁₄ -C ₁₇ heavy and C ₁₈ -C ₅₀ long chain paraffins.

As specific examples of particularly suitable non-chlorinated paraffins, mention may be made of products sold under the trade names 1040 and 1080 by the company Janex in particular.

The content of non-chlorinated paraffin (s) in the grease according to the invention corresponds to 2 to 10% by weight and preferably 2 to 7% by weight.

Grease is at least one non- before or after the melting / recrystallization and the melting / recrystallization step of the soap in the oily diorganopolysiloxane polymer (s), preferably after the melting / recrystallization step. Prepared by incorporation of chlorinated paraffin and cooling of the grease. The procedure is carried out in a device designed for the blending of viscous mixtures; Thus, for example, blenders and mills are particularly suitable for the preparation. In later steps, if necessary, the grease may be worked, for example in a roll mill or a colloidal mill, to be milled to suit the intended use of the rheology and / or appearance of the grease. Can be.

These greases are successfully used as treatments and / or protective agents and / or lubricants in the field of mobile metal mobile components; They have a good cohesion, especially at low temperatures, so they are thus particularly effective, especially at low temperatures, between components relating to the drive system, for example in the automotive sector, between components relating to vehicle clutch cables, transmissions or starters, This helps to avoid skating.

The following examples illustrate the invention.

Example 1

1. The preparation of silicone greases according to the invention is illustrated below :

Formulations of the greases are shown in Table 1 below.

Ingredient / Procedure Control Example # 1 Example # 2 Lithium stearate (% by weight) 22 22 22 Oil 510V100 (wt%) (1) 78 73 73 Non-chlorinated isoparaffin 1080 (% by weight) (2) 0 5 2.5

(1) Oil 510V100: Poly (dimethyl) (methylphenyl) siloxane copolymer having a viscosity of 100 mPa · s at 25 ° C. and containing 15% by weight of Si (C ₆ H ₅ ) (CH ₃ ) O _2/2 siloxy units ;

(2) Isoparaffin 1080: A product sold by Janex under the name "Process Oil 1080", having the following characteristics: Viscosity at 100 ° C: 8 kCSt; Flash point: 261 ° C .; CAS No .: 72623-87-1.

The greases were prepared using an arm kneader. The product went through a melt / recrystallization cycle under the following conditions: Melting of the soap at about 200 ° C., followed by cooling to 23 ° C.

The isoparaffin 1080 additive was added at the end of the formulation at temperatures around 80 ° C. at concentrations of 5% by weight in Test 1 and 2.5% by weight in Test 2.

2. The general properties of the greases prepared according to paragraph 1 are given below :

characteristic Control Example 1 Example 2 Flow threshold at -40 ° C in Pa (3) 320 3100 2200 Mixed penetration (1/10 mm) (4) 290 295 308 % Volatiles (5) <3 <3 <3 Leaching (6) <4 <4 <4

(3) flow threshold:

Device used :

Rheometric scientific SR5 stress control rheometer;

Julabo F25 thermostat;

25 mm cone / plate, angle 0.0984 rad .:

+ Gap: 0.0559 mm,

+ Serial number 4144.

Procedure :

1) Cool the plate to -40 ° C using a circulation of ethanol-based fluid maintained at -40 ° C with a cooling bath and cardice in combination;

2) set the device to zero and if the gap is adjusted, check the inertia of the empty spindle until it reaches a constant value;

3) remove condensation on the plate with acetone;

4) insert the product, then adjust the gap;

5) The analysis is selected as follows: scanning in a dynamic stress mode of 1 to 5000 Pa at a frequency set to 6.28 rad / s;

6) Once the plate has stabilized at -40 ° C, start the assay;

7) Analyze each sample twice to check the reproducibility of the measurement.

It can be pointed out that the analysis is performed at a frequency of 1 Hz at -40 ° C. This seems to correlate to a frequency of about 3000 rpm at ambient temperature.

(4) Mixing Lead: The lead of the grease sheared by a specific tool is evaluated by measuring the penetration of the cone into the grease under the conditions specified in standard NF T 60132 (corresponding to ASTM Standard D 217);

(5)% volatiles: Working with 10 g of grease, determine the weight loss of the grease placed for 24 hours in an oven at 150 ° C .;

(6) Leaching: Working according to the conditions of standard FTMS 791321, measure the amount of oil that has leaked out through a metal grill in which 10 g of grease kept at 150 ° C. for 24 hours.

Examples 2-5

In the following, another preparation of silicone grease according to the invention is illustrated:

Greece is:

Prepared according to the same protocol as described in Example 1, item 1, yet another non-chlorinated isoparaffin was used at 5% by weight in the grease (see Table 3 below),

Provide the following properties (see Table 3 below):

Control Example 1 Composition-Isoparaffin-Weight% in Greece  --  1040 (7) 5 Characteristics-Flow Threshold (4)-Penetration Lead (5)-% Volatiles (6)-Leaching (7)  320 290 <3 <4  2002 317 <3 <4

(7): A product sold under the name Process Oil # 1040 by Janex, having the following characteristics: Viscosity at 100 ° C .: 8 μcSt; Flash point: 217 ° C .; CAS No .: 72623-87-1

It is clear from the table that the addition of a non-chlorinated isoparaffin-based additive substantially increases the flow threshold of the control silicone grease.

Claims (10)

A high cohesive silicone grease containing Grease, characterized in that it is selected from the group consisting of C ₁₀ -C ₁₃ short chain paraffin, C ₁₄ -C ₁₇ heavy chain paraffin and C ₁₈ -C ₅₀ long chain paraffin: At least one oily diorganopolysiloxane polymer, 10-30% by weight of at least one organometallic soap, relative to the weight of silicon grease, and At least one paraffin from 1 to 10% by weight. A grease according to claim 1, wherein non-chlorinated C ₁₄ -C ₁₇ heavy chains and C ₁₈ -C ₅₀ long chain paraffins are used. The grease of claim 1 or 2 having a high flow threshold of greater than 1000 Pa at −40 ° C. 4. 4. The grease of claim 1, further comprising 1 to 8% by weight of auxiliary additive (s). 5. The grease according to claim 1, wherein the oily diorganopolysiloxane polymer corresponds to the following general formula: (R) ₃ SiO [Si (R) ₂ O] _n Si (R) ₃ {Wherein symbol R may be the same or different and represents a hydrocarbon-based radical having 13 or less carbon atoms without aliphatic unsaturation, and symbol n represents any number in the range from 30 to 1500}. 6. The organometallic soap according to any one of claims 1 to 5, wherein the organometallic soap is a C10-C32 higher fatty acid and metal Li, Na, K, Cs, Mg, Ca, Sr, Cd, Zn, Pb and Co compounds. Greece, which is derived from. The grease according to any one of claims 1 to 6, wherein a non-hydroxylated organometallic soap derived from a non-hydroxylated fatty acid is used. A process for preparing silicone grease as claimed in any one of claims 1 to 7, wherein before or after the melting / recrystallization of the soap and the melting / recrystallization step in the oily diorganopolysiloxane polymer (s), A process characterized by the incorporation of at least one non-chlorinated paraffin as defined in claim 1. Use of the silicone grease as claimed in any one of claims 1 to 7 having a high flow threshold of greater than 1000 Pa at −40 ° C. as a treatment and / or protector and / or lubricant in the field of mobile metal mobile components. Use according to claim 9, characterized in that the components relate to a drive device consisting of a vehicle clutch cable, a transmission or a starter in the automotive field.