The present invention relates to a composition based on methyl esters of fatty acids derived from castor oil having a low pour point. This composition is particularly useful as a lubricant or to facilitate the stripping of concrete.

TECHNICAL BACKGROUND

It is known to be transesterified vegetable or animal oils, which are mixtures of different fatty acids to produce useful products such as for lubrication.

The fatty acid composition varies considerably from vegetable or animal oil to another, so that each transesterified oil has different properties.

A particularly useful product, such as a lubricant or as an agent for demoulding of concrete, is a mixture of methyl esters of fatty acids derived from castor oil. This product predominantly contains methyl esters of fatty acids C1 1-C22, the main ones being methyl linoleate and methyl oleate. This product also contains two specific compounds which generally not found in products derived from other vegetable oils, namely 10-undecylenic acid and methyl ricinoleate.

This product is sold in particular by Arkema under the designation Oleris® Esterol A. However, a disadvantage of this product is that it has a relatively high pour point of about + 6 ° C (according to ASTM D97) . Therefore, use of the product is difficult in cold weather.

It is known to use additives for lowering the pour point to reduce the pour point of various products derived from vegetable or animal oils.

Thus, EP 0543356, EP 0626442, US 6409778, US 6.051, 538 and US 201 1/296743 describe various compositions in which additives for lowering the pour point are used.

However, in general, the possibility of lowering the pour point of a product derived from a vegetable or animal oil in order to allow its use in cold weather conditions depends on the nature and properties of the product. Therefore, there is a need to achieve a better mixture of methyl esters of fatty acids derived from castor oil in order to allow its use in cold weather.

SUMMARY OF THE INVENTION

The invention relates firstly to a composition comprising:

- at least 95% by weight of a mixture of methyl esters of fatty acids of castor oil;

- a step-down additive pour point;

the pour point of the composition being less than or equal to 0 ° C. According to one embodiment, the pour point of the composition is less than or equal to -5 ° C, preferably less than or equal to -9 ° C.

According to one embodiment, the mixture of methyl esters of fatty acids of castor oil has an iodine value of 100 to 120 g / 100 g and includes, in weight proportions:

- from 5 to 20%, preferably 8 to 12% methyl stearate;

- 20 to 40%, preferably from 25 to 35% methyl oleate;

- 30 to 50%, preferably 35 to 45% methyl linoleate; - less than 10%, preferably less than 8.5% methyl palmitate;

- 1, 5-4%, preferably 2 to 3% methyl ricinoleate;

- from 0.4 to 1, 5%, preferably 0.6 to 1% of 10- undecylenic acid.

According to one embodiment, the composition comprises an additive mass proportion down the pour point of 1 to 2%, preferably 1 2 to 1 8%.

According to one embodiment, the downcomer additive pour point is an acrylic polymer (preferably in accordance with the general formula shown below) dissolved in an oil, the proportions being preferably from 60 to 100 parts of acrylic polymer for 15-40 oil shares.

According to one embodiment, the oil is a paraffinic distillate.

According to one embodiment, the additive has:

- a viscosity at 100 ° C according to ASTM D445 of 200 to 500 mm 2 / s, preferably 300 to 400 mm 2 / s;

- a pour point according to ASTM D97 or lower standard equal to -30 ° C, preferably less than or equal to -36 ° C;

- an acid value according to ASTM D974 of less than or equal to

0.6 mg KOH / g, preferably less than or equal to 0.5 mg KOH / g. The invention also relates to the use of the above composition, as lubricant, release agent concrete, degreasing agent or cleaning agent.

The present invention overcomes the disadvantages of the prior art. In particular, it provides a mixture of methyl esters of fatty acids derived from castor oil which can be used in cold weather.

This is accomplished through the use of an additive for lowering the pour point of the mixture at less than 0 ° C, preferably less than -5 ° C or less than -9 ° C.

BRIEF DESCRIPTION OF FIGURES

1 shows the kinetics of crystallization of various compositions, estimated by the thickness of the crystal layer formed (ordinate, in mm) as a function of temperature (x-axis, in ° C). Details are given in Example 1 below.

EMBODIMENTS DESCRIPTION OF THE INVENTION

The invention is now described in more detail and not limited to the following description.

The composition according to the invention is obtained by mixing a mixture of methyl esters of fatty acids derived from castor oil and a down additive pour point.

The mixture of methyl esters of fatty acids derived from castor oil is obtained by transesterification of castor oil with methanol. The transesterification rate of the mixture is not necessarily 100%, meaning that the mixture of methyl esters in question may include some proportion of non-esterified fatty acids.

The mixture of methyl esters of fatty acids derived from castor oil is preferably characterized by a pour point according to ASTM D97 standard 5 and 8 ° C; and / or an iodine number of 100 to 120 g / 100 g. The iodine value may be determined according to ISO 3961 standard.

The mixture of methyl esters of fatty acids preferably comprises:

- from 5 to 20%, preferably 8 to 12% of methyl stearate (C18: 0);

- 20 to 40%, preferably from 25 to 35% methyl oleate (C18: 1);

- 30 to 50%, preferably 35 to 45% methyl linoleate (C18: 2);

- less than 10%, preferably less than 8.5% of methyl palmitate (C16: 0);

- 1, 5-4%, preferably 2 to 3% methyl ricinoleate (C18: 1 (OH));

- from 0.4 to 1, 5%, preferably 0.6 to 1% of 10- undecylenic acid (C1 1: 1).

The additive pour point depressant is selected such that it lowers the pour point of the composition according to the invention below 0 ° C (preferably below -1 ° C or -2 ° C, or -3 ° C or -4 ° C or -5 ° C or -6 ° C or 7 ° C or 8 ° C, or -9 ° C, according to ASTM D97).

It may include of an acrylic polymer (including acrylic copolymers) dissolved in an oil. The relative proportions are preferably 60 to 100 parts acrylic polymer to from 15 to 40 parts oil.

The acrylic polymer is preferably a polyalkyl methacrylate of general formula:

wherein n is an integer which preferably ranges from 200 to 2000 and each R is independently an alkyl group in C1 to C22.

The oil may for example be obtained by catalytic hydrogenation of a petroleum fraction and predominantly comprise hydrocarbons C15 to C30, mainly saturated, and have a viscosity less than 19 cSt at 40 ° C. It can especially be oil referenced as CAS 64742-55-8.

The oil may also be obtained by catalytic hydrogenation of a petroleum fraction and predominantly comprise hydrocarbons C20 to C30, mainly saturated, and have a viscosity greater than 19 cSt at 40 ° C. It can especially be oil referenced as 64742-54-7 CAS number.

The oil may also be obtained from a petroleum fraction by removing paraffin by crystallization from a solvent and mainly comprise hydrocarbons C20 to C30, and have a viscosity greater than 19 cSt at 40 ° C. It can especially be oil referenced as CAS 64742-65-0.

One can also use a mixture of the above oils.

Preferably the additive has:

- a viscosity at 100 ° C according to ASTM D445 of 200 to 500 mm 2 / s, preferably 300 to 400 mm 2 / s; and or

- a pour point according to ASTM D97 or lower standard equal to -30 ° C, preferably less than or equal to -36 ° C; and or

- an acid value according to ASTM D974 less than or equal to 0.6 mg KOH / g, preferably less than or equal to 0.5 mg KOH / g.

A particularly suitable additive is the product marketed by Evonik under the VISCOPLEX® reference 1 1 -21.

The additive may be present in the composition in a weight proportion of 0.1 to 5%, and preferably from 1 to 2%. preferred contents ranges are: 1, 0-1, 1%; 1, 1-1, 2%; 1, 2-1, 3%; 1, 3-1, 4%; 1, 4 to 1, 5%; 1, 5-1, 6%; 1, 6-1, 7%; 1, 7-1, 8%; 1, 8-1, 9%; and 1, 9 to 2.0%. A content by weight of about 1, 5% is particularly suitable.

The polymer content of acrylic copolymer in the composition of the invention is preferably from 0.5 to 2%, more preferably from 0.8 to 1, 4% (especially 0.8 to 0.9% or 0.9 to 1, 0% or 1, 0-1, 1%, or 1, 1-1, 2%, or 1, 2-1, 3%, or 1, 3 1, 4%).

According to one embodiment, the composition consists essentially of the mixture of methyl esters of fatty acids derived from castor oil and the downcomer additive pour point. According to another embodiment, the composition consists of the mixture of fatty acid methyl esters derived from castor oil and the downcomer additive pour point.

EXAMPLES

The following examples illustrate the invention without limiting it.

example 1

Various additives pour point depressants are added to height of 1 to 2.5% in a mixture of methyl esters of fatty acids derived from castor oil sold under the designation A Oleris® Esterol by Arkema (d flow: + 6 ° C).

The additives used are:

- VISCOPLEX® 10-310 (Evonik): acrylic copolymer in an amount greater than or equal to 60%, combined with rapeseed oil having a viscosity of 1800 mm 2 / s at 100 ° C;

- VISCOPLEX® 1 1 -21 (Evonik): acrylic polymer in an amount greater than or equal to 60%, combined with a neutral oil having a viscosity of 400 mm 2 / s at 100 ° C;

- VISCOPLEX® 1 -180 (Evonik): acrylic copolymer in a content of 40 to 70%, combined with a neutral oil having a viscosity of 300 mm 2 / s at 100 ° C;

- VISCOPLEX® 1 -255 (Evonik): acrylic copolymer in a content of 15 to 40%, combined with a neutral oil having a viscosity of 45 mm 2 / s at 100 ° C.

The pour points of the compositions thus obtained are summarized in the following table:

pour point (ASTM D97)

It is found that the additive VISCOPLEX® 1 -21 1 is particularly interesting because it lowers the pour point of -9 ° C at a concentration of only 1, 5%.

Moreover, crystallization kinetics measurements were performed between 5 and -3 ° C by measuring the thickness of the crystal layer formed in a preserved sample in a test tube (height

filling 55 mm). These measures have focused on four compositions made with 1, 5% of the above four additives; as well as a control sample of Oleris® Esterol A. The results are shown in Figure 1. They show that the additive VISCOPLEX® 1 -21 1 is the one that provides the slower crystallization kinetics.

Curve 1 represents the control composition without additive, the curve 2 represents the composition made with the VISCOPLEX® -255 1, curve 3 shows the composition made with the VISCOPLEX® 1 -180, curve 4 shows the composition made with the Viscoplex ® 10-310 and the curve 5 shows the composition made with the VISCOPLEX® 1 1 -21.
example 2
The consistency of various compositions prepared with the same products as in Example 1 was evaluated after storage under static conditions at -7 ° C for 7 days.

The results are shown in the table below:

CLAIMS

Composition comprising:

- at least 95% by weight of a mixture of methyl esters of fatty acids of castor oil;

- a step-down additive pour point;

the pour point of the composition being less than or equal to 0 ° C.

A composition according to claim 1, wherein the pour point is less than or equal to -5 ° C, preferably less than or equal to -9 ° C.

The composition of claim 1 or 2, wherein the mixture of methyl esters of castor oil fatty acids has an iodine number of 100 to 120 g / 100 g and includes, in weight proportions:

- from 5 to 20%, preferably 8 to 12% methyl stearate;

- 20 to 40%, preferably from 25 to 35% methyl oleate;

- 30 to 50%, preferably 35 to 45% methyl linoleate;

- less than 10%, preferably less than 8.5% methyl palmitate;

- 1, 5-4%, preferably 2 to 3% methyl ricinoleate;

- from 0.4 to 1, 5%, preferably 0.6 to 1% of 10- undecylenic acid.

Composition according to one of claims 1 to 3, having a proportion by weight of additive down the pour point of 1 to 2%, preferably 1 2 to 1 8%.

Composition according to one of claims 1 to 4, wherein the downcomer additive pour point is an acrylic polymer dissolved in an oil, the proportions being of

preferably from 60 to 100 parts acrylic polymer to from 15 to 40 parts oil.

6. The composition of claim 5, wherein the acrylic polymer has the formula:

wherein n is an integer of preferably from 200 to 2000 and each R is an alkyl C1-C22.

The composition of claim 5 or 6, wherein the oil is a paraffinic distillate.

Composition according to one of claims 1 to 7, wherein the additive has:

- a viscosity at 100 ° C according to ASTM D445 of 200 to 500 mm 2 / s, preferably 300 to 400 mm 2 / s;

- a pour point according to ASTM D97 or lower standard equal to -30 ° C, preferably less than or equal to -36 ° C;

- an acid value according to ASTM D974 less than or equal to 0.6 mg KOH / g, preferably less than or equal to 0.5 mg KOH / g.

Use of the composition according to one of claims 1 to 8, as lubricant, release agent concrete, degreasing agent or cleaning agent.