AT514523A1 - Sägekettenschmiermittel - Google Patents

Abstract

The invention relates to a saw chain oil which comprises glycerol, water and at least one adhesive and is characterized in that at least one organic sulfur compound is dissolved as an additional lubricant in the saw chain oil.

Description

The present invention relates to a new saw chain lubricant.

BACKGROUND OF THE INVENTION While oil-based lubricating oils have mostly been used as saw chain oils for lubricating the chain of power saws, biodegradable -natural or synthetic-oils, e.g. based on vegetable oil or glycerol, ein¬gesetzt.

In order to reduce the throwing off of the saw chain oil from the rotating chain as well as to maintain a certain lubricant film thickness, long sticking agents are added to this oil side. Thus, for example, DE 31 23 726 A1 discloses a sticking oil serving as a saw chain oil, among others, which may be based inter alia on glycols or glycerol or aqueous mixtures thereof and comprises up to 2.0% by weight of polyacrylamide as an adhesive ,

Other suitable adhesives are, for example, other natural or synthetic polymers, e.g. Polyvinylpyrrolidone (PVP). The latter is e.g. in EP 2,180,034 A1 as an adhesive in a saw chain oil otherwise composed mainly of glycerol, water, methanol and surfactant (in well-defined proportions). In addition, for example, corrosion inhibitors and / or fragrances may be included.

To further reduce the wear of the chainsaw, it is also known to add solid lubricants sawtooth oils. However, this is disadvantageous insofar as it is usually on the one hand to heavy metal sulfides, such. M0S2, which represents a heavy environmental impact.

Against this background, the object of the invention was the development of a saw chain oil with which the above disadvantages can be at least partially eliminated.

DISCLOSURE OF THE INVENTION

This object is achieved by the present invention by providing a saw chain oil which comprises as basic constituents glycerol, water and at least one adhesive and is characterized in that at least one organic sulfur compound is present dissolved in the oil as an additional lubricant.

By using one or more, in the base mixture of glycerol and water-soluble organic sulfur bonds as additional (s) lubricants on the one hand lubrication is improved, the inventor on the one hand zunut¬ze the well-known lubricating effect of sulfur as a component of common lubricant additives and on the other hand Solubility of the additive according to the invention causes it to be unable to separate from the oil before it unfolds its lubricating action.

Without wishing to be bound by any particular theory, the inventor assumes for the mode of action of the additives according to the invention that in operation at least partial decomposition of the organic sulfur compound (s) in the oil occurs, thereby producing in situ new compounds of sulfur similar to one another Liche lubricating effect as a sulfide-containing solid lubricant, even if the starting compound itself shows no such effect.

For this reason, the at least one organic sulfur compound is not particularly limited as long as it increases the lubricity of the saw chain oil during operation, and can be selected, for example, from sulfur-containing heterocycles, thiols, sulfoxides, sulfones, sulfonic acids, sulfinic acids, sulfuric acid esters, disulfides -den as well as salts of these compounds, eg Ammonium, alkali metal or Erdakali¬metallsalzen thereof, to be selected. The use of ammonia, alkali metal or alkaline earth metals as base partners of such salts reduces the costs compared with the use of other inorganic or organic bases and is largely harmless with regard to environmental pollution.

Preferably, the at least one organic sulfur compound is selected from salts of thiols, sulfonic acids, sulfinic acids and sulfuric acid esters because the presence of ionic groups increases the solubility of the compound in the polar glycerol / water mixture. In some preferred embodiments, the at least one organic sulfur compound is selected from salts of thiols, sulfonic acids, sulfinic acids and sulfuric acid esters which comprise one or more sulfur-containing heterocyclic radicals, since the presence of several sulfur atoms in the molecule on the one hand tends to improve the lubricating effect and On the other hand, the presence of organic heterocycles controls the polarity of the molecule. In the case of excessively high polarity of the additive according to the invention, there is the danger that the mixture will precipitate out of the mixture during mixing of the glycerol / water-based saw chain oil with mineral oils or relatively non-polar vegetable oils, and in turn cause segregation of the solid phase from the liquid phase it can come.

For these reasons, the at least one organic sulfur compound is particularly preferably selected from thiolates of sulfur-containing heterocycles, since thiols, owing to the absence of oxygen atoms, are less polar than, for example, sulfonic acids, sulfinic acids or sulfuric acid esters.

The inventor has so far achieved particularly good results with the disodium salt of 1,3,4-thiadiazole-2,5-dithiol, which thus currently represents the organic sulfur compound of choice. This is also because the compound is commercially available, e.g. Sigma-Aldrich, as a free dithiol and also as its disodium salt. Since the latter is offered even at a lower price than the free dithiol and according to the present invention is preferred for the above reasons, the synthesis to be accomplished in a relatively simple manner is accomplished by reacting the free dithiol with e.g. aqueous NaOH not to be preferred.

Commercial availability relies on the suitability of 1,3,4-thiadiazole-2,5-di-thiol derivatives as additives to flame retardants and as a reagent for the more complex heterocycles due to the high nucleophilicity of the three heteroatoms.

In contrast, the inventor has surprisingly found excellent performance of the compound as a lubricating oil additive.

The amount of the at least one organic sulfur compound is generally not particularly limited, and one skilled in the art will readily be able to determine the preferred and optimum amounts of the particular sulfur compound without undue experimentation but by means of straightforward series experiments. The most preferred 1,3,4-thiadiazole-2,5-dithiol disodium salt will have a preferred range of 0.1 to 2 wt%, more preferably 0.4 to 1 wt%. In general, the proportions to be selected depend logically on the other composition of the saw chain oil according to the invention and its intended conditions of use.

The ratios between glycerol, water and adhesive (s) are not particularly limited, as long as the saw chain oil as a whole shows the desired effect. This depends largely on the viscosity of the oil and the Betriebsbedingun¬gen in its use. Thus well known and proven conditions, e.g. as described in DE 31 23 726 A1 and EP 2,180,034 A1 cited at the outset, it being possible for a saw chain oil according to the invention to have a slightly lower viscosity than an oil due to the solubility of the at least one organic sulfur compound as dissolved lubricating additive according to the prior art with heterogeneously present solid lubricant additive. For the at least one adhesive, a selection can also be made from the known and proven agents, for which, in addition to the above-mentioned transversal polyacrylamide and polyvinylpyrrolidone, other natural or synthetic polymers are also suitable.

As for other components of the saw chain oil of the invention other than those mentioned above, the saw chain oil of the present invention is also not particularly limited as long as the advantageous effects of the invention and other desired properties are not impaired. For example, other ingredients of the oil can be made from common mineral and vegetable lubricants, e.g. sulfated plant lubricants, surfactants, corrosion inhibitors, viscosity regulators, pH regulators, antioxidants, dyes and perfumes. In particular, mixtures of a saw chain oil of the invention having the above-recited base composition and one or more mineral and vegetable oils may be advantageous for certain applications, and therefore are preferred embodiments of the invention.

For this reason, the saw chain oil of the present invention also preferably comprises at least one surfactant as an additional component to increase the miscibility of the aqueous glycerol-based oil of the invention with such more apolar oils and the solubility of the at least one organic sulfur compound and the adhesive in the mixture ,

The amount of the at least one surfactant thereby varies from its own nature as well as in dependence on the other components of the saw chain oil according to the invention. When using polyvinylpyrrolidone or other synthetic plastics as an adhesive in a glycerine / water-based saw chain oil according to the invention, a content of at least 2% by weight of the at least one surfactant has proven to be advantageous in order to achieve the above miscibility or solubility advantages so that, for example, there is no segregation of the saw chain oil in the oil tank of the saw.

In addition, if the saw chain oil is to be mixed with a relatively non-mineral mineral or vegetable oil, e.g. with 5% by weight rapeseed oil, at least 3% by weight of the at least one surfactant have proven useful.

EXAMPLES

Hereinafter, the present invention will be described in detail by way of non-limiting examples.

Comparative Example 1

As a comparative example, a saw chain oil according to the prior art based on the disclosure of EP 2.180.034 A1 was prepared. The components listed in the following Table 1 were mixed together in the given amounts at room temperature:

Table 1

As " unalterable contamination " The glycerol used in such mixtures is usually also methanol in a proportion of up to about 0.5 wt .-% ent. However, since this can vary relatively widely depending on the manufacturer, and sometimes even from batch to batch, it is not mentioned separately here.

example 1

To a part of the mixture (100 parts by weight) prepared in Comparative Example 1 was added 0.5 part by weight of 1,3,4-thiadiazole-2,5-dithiol disodium salt as an additional lubricant according to the present invention and homogeneously dissolved therein by stirring at room temperature for 2 minutes.

Example 2

The two saw chain oils produced were tested according to the following standards:

Density at 20 ° C DIN 51757

Viscosity at 40 ° C DIN 53015

Viscosity at 100 ° C DIN 51562 VKA good and welding strength: DIN 51350

Resilience (Brugger test): DIN 51347 VKA stands for "four-ball apparatus", a test instrument for determining the extreme pressure ("EP") properties and the wear characteristics of

Liquids. Here, a force acting on a rotating ball (running ball), which slides on three identi¬schen further balls (stationary balls), from above a force that is gradually increased until it comes to welding of the balls due to the friction-induced heating. The force measured immediately before the welding of the balls is given as good force, those afterwards as Verschwei߬kraft.

The Brugger test measures the wear of defined, pressed-together and relatively moving friction surfaces using a lubricant. The measured value given is the quotient of the contact force and the (projected) wear surface generated with it.

The results of all tests, together with the external appearance, i.e. the coloration of the oils according to visual inspection, are given in Table 2 below.

Table 2

It can be seen that, with otherwise approximately equal values for density and viscosity, the inventive saw chain oil of Example 1 in the four-ball apparatus and the Brugger tester gave significantly better results in terms of goodness, weld strength, and load capacity than the comparative example ¬spiel.

The addition of only 0.5 part by weight of 1,3,4-thiadiazole-2,5-dithiol disodium salt thus surprisingly (almost) doubled the values for good power, welding strength and load capacity.

Examples 3 to 6

In order to test the miscibility of saw chain oils according to the present invention with conventional hydrophobic lubricating oils, the surfactant-containing mixtures indicated in Table 3 below were prepared by simply mixing the respective components at room temperature.

Table 3

The respective amounts are again given in% by weight, in each case turkey red oil (sulfonated castor oil) was used as the surfactant, and TDDN stands for 1,3,4-thiadiazole-2,5-dithiol disodium salt.

In each case 100 parts by weight of these four examples of saw chain oil according to the invention were mixed homogeneously with 10 parts by weight rapeseed oil or mineral oil for 1 min, then allowed to stand and observed whether and when there was a segregation of a second liquid phase. The results are shown in Table 4 below.

Table 4

&Quot; quot No &; Demixing for the mixture from Example 6 means that even after 24 h no second phase was observed, after which the tests were stopped in each case.

Although Turkish red oil was used as a surfactant in the above mixtures, the inventor has obtained similar results in other preliminary experiments with other common surfactants (sodium lauryl ether sulfate, Polyalkylenglykolethem 25-30 carbon atoms and weite¬ren sulfated vegetable oils) in the majority of cases.

In any event, it follows from the results in Table 4 that a surfactant content of at least 2% by weight is preferred in order to ensure adequate miscibility of the saw chain oil according to the invention with conventional, relatively hydrophobic lubricating oils. Even more preferred is at least 3% by weight, especially at least 5% by weight, surfactant.

The present invention thus provides new additives to saw chain oils which cause the lubricating performance of the oil to be virtually doubled. With appropriate addition of surfactant, these saw chain oils of the invention are also well-tolerated with conventional lubricating oils.

Claims (10)

PATENT CLAIMS 1. Saw chain oil comprising glycerin, water and at least one adhesive, characterized in that at least one organic sulfur compound is dissolved as an additive lubricant in the saw chain oil. Saw chain oil according to claim 1, characterized in that the at least one organic sulfur compound is selected from sulphurous heterocycles, thiols, sulphoxides, sulphones, sulphonic acids, sulphinic acids, sulfuric acid esters, disulphides and salts of these compounds, e.g. Ammonium, alkali metal or Erdakali¬metallsalzen thereof, is selected. 3. Sägekettenöl according to claim 2, characterized in that the at least one organic sulfur compound is selected from salts of thiols, sulfonic acids, sulfinic acids and sulfuric acid esters. 4. Sägekettenöl according to claim 3, characterized in that the at least one organic sulfur compound is selected from salts of thiols, sulfonic acids, sulfinic acids and sulfuric acid esters which comprise one or more sulfur-containing heterocyclic radicals. Saw chain oil according to claim 3, characterized in that said at least one organic sulfur compound is selected from thiolates of sulfur-containing heterocycles. Saw chain oil according to claim 5, characterized in that said at least one organic sulfur compound is or comprises the disodium salt of 1,3,4-thiadiazole-2,5-dithiol. 7. chain saw oil according to one of the preceding claims, characterized gekenn¬zeichnet that one or more other components selected from mineral and vegetable lubricants, e.g. sulfated plant lubricants, surfactants, corrosion inhibitors, viscosity regulators, pH regulators, antioxidants, dyes and fragrances. Saw chain oil according to claim 7, characterized in that it comprises at least one surfactant. 9. saw chain oil according to claim 8, characterized in that it comprises at least 2Gew .-% of at least one surfactant. 10. saw chain oil according to claim 9, characterized in that it comprises at least 3Gew .-% of at least one surfactant.