SULPHUR-CONTAINING POLYESTER

Abstract

The present invention relates to a sulphur-containing polyester capable of being obtained by a process comprising esterification reactions between a polyol and a carboxylic acid and a thiolactic acid, or by a process comprising an esterification reaction between a partially esterified polyol and a thiolactic acid. It also concerns its use as a multiproperty additive, and compositions comprising it.

Claims

1. A sulphur-containing polyester capable of being obtained by a process comprising esterification reactions between a polyol and a carboxylic acid and a thiolactic acid, or by a process comprising an esterification reaction between a partially esterified polyol and a thiolactic acid.

2. The sulphur-containing polyester of claim 1, wherein the partially esterified polyol is capable of being obtained by an esterification reaction between a polyol and a carboxylic acid.

3. The sulphur-containing polyester of claim 1, wherein the polyol is glycerol, polyglycerols, ethylene glycol, propylene glycol, neopentyl glycol, 1,3-propanediol, polyethylene glycol, polypropylene glycol, pentaerythritol, trimethylopropane or dimer diols.

4. The sulphur-containing polyester of claim 1, wherein the molar equivalent ratio (carboxylic function(s) of the carboxylic acid)/(carboxylic function of the thiolactic acid) is comprised between 0.8 and 4.

5. The sulphur-containing polyester of claim 1, wherein the carboxylic acid is a fatty acid.

6. A process for preparing a sulphur-containing polyester comprising an esterification reaction between a partially esterified polyol and a thiolactic acid.

7. The process of claim 6, wherein the partially esterified polyol is obtained by an esterification reaction between a polyol and a carboxylic acid.

8. A process for preparing a sulphur-containing polyester comprising esterification reactions between a polyol and a carboxylic acid and a thiolactic acid.

9. A method for improving extreme pressure properties of a surface comprising applying the sulphur-containing polyester of claim 1 to a surface.

10. A method for reducing friction between two surfaces or reducing wear on a surface comprising applying the sulphur-containing polyester of claim 1 to a surface.

11. (canceled)

12. A composition comprising the sulphur-containing polyester of claim 1, and an oil.

13. The composition of claim 12, further comprising an additive other than a sulphur-containing polyester.

14. A lubricant composition comprising the composition of claim 12.

15. A process for preparing a composition comprising mixing the sulphur-containing polyester of claim 1, an oil, and optionally an additive other than a sulphur-containing polyester of claim 1.

Description

[0164] The invention is further described in the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples.

[0165] FIG. 1 represents Stribeck curves obtained from a mineral oil, from the composition 7 and from comparative composition 1;

[0166] FIG. 2 represents Stribeck curves obtained from a mineral oil, from the composition 8 and from comparative composition 2.

MATERIALS USED IN EXAMPLES

[0167] Thiolactic acid from Bruno Bock Chemische Fabrik GmbH & Co KG; [0168] Partially esterified polyol: [0169] propyleneglycol monooleate (PGMO) (CAS:1330-80-9); [0170] Polyols: [0171] glycerol (G) from KLK Oleo; [0172] trimethylolpropane (TMP) from Perstorp; [0173] polyglycerol-3 (PG-3) from Spiga Nord S.p.A.; [0174] polyglycerol-4 (PG-4) from Spiga Nord S.p.A.; [0175] polyglycerol-10 (PG-10) from Spiga Nord S.p.A.; [0176] pentaerythritol from Perstorp; [0177] Fatty acids: [0178] oleic acid (C18:1) from KLK Oleo; [0179] isostearic acid (isoC18), Radiacid 0907 from Oleon; [0180] Comparative additive: [0181] medium chain chlorinated paraffin (MCCP), Haihang Industry Co., Ltd; [0182] Oils: [0183] Mineral oils: [0184] naphthenic oil: Tudalen 3248 from H&R Group; [0185] paraffinic oil: Tudalen 10F from H&R Group; [0186] Synthetic oil: trimethylolpropane trioleate (TMPTO), Radialube 7364 from Oleon; [0187] Vegetable oil: rapeseed oil (CAS:8002-13-9); [0188] Catalyst: methanesulfonic acid (CAS: 75-75-2).

Example 1: Preparation of Sulphur-Containing Polyesters According to the Invention

[0189] 1.1. From a Partially Esterified Polyol and Thiolactic Acid

[0190] Sulphur-containing polyester P1 is prepared in a four-necked round bottom flask equipped with a temperature probe, a stirrer shaft, a condenser, and a gas sparger, where is charged of 1 mol PGMO and 1 mol of thiolactic acid. The temperature of the mixture is set at 170° C. until the acid value is less than 15 mg KOH/g.

[0191] Then, the reaction mixture is allowed to cool down to room temperature.

[0192] The molar equivalent ratio (hydroxyl function of the partially esterified polyol)/(carboxyl function of the thiolactic acid) is of 1.

[0193] Acid value (AV) is defined as the number of milligrams of potassium hydroxide required to neutralize acid functions present in one gram of a chemical substance. This value and in all examples unless otherwise indicated, was measured according to standard AOCS Cd 3d-63.

[0194] 1.2. From a Polyol, a fatty acid and thiolactic acid

[0195] 1.2.1. In Two Steps

[0196] A four-necked round bottom flask equipped with a temperature probe, a stirrer shaft, a condenser, and a gas sparger, is charged of a polyol and a fatty acid. The mixture is heated up to 230° C. under stirring, until the acid value is less than 5 mg KOH/g.

[0197] The temperature of the mixture is then cooled down to 80° C.

[0198] Thiolactic acid is then added to the mixture. The temperature of the mixture is set at 170° C. until the acid value is less than 15 mg KOH/g.

[0199] Then, the reaction mixture is allowed to cool down to room temperature.

[0200] Quantities of components used to prepare sulphur-containing polyesters (P2 to P9) are described in Table 1 below:

TABLE-US-00001 TABLE 1 Contents of sulphur-containing polyesters according to the invention Penta- Thiolactic G TMP PG-3 PG-4 PG-10 erythritol C18:1 IsoC18 acid (mol) (mol) (mol) (mol) (mol) (mol) (mol) (mol) (mol) P2 1 2 0.86 P3 1 2 0.86 P4 1 3.32 1.42 P5 1 2.85 2.85 P6 1 3.99 1.71 P7 1 3.99 1.71 P8 1 7.98 3.42 P9 1 2.66 1.14

[0201] For P2-P4 and P6-P9, the molar equivalent ratio (hydroxyl functions of the polyol)/(carboxyl function of the carboxylic acid) is of 1.5 and the molar equivalent ratio (carboxyl function of the carboxylic acid)/(carboxyl function of the thiolactic acid) is of 2.3.

[0202] For P5, the molar equivalent ratio (hydroxyl functions of the polyol)/(carboxyl function of the carboxylic acid) is of 2.1 and the molar equivalent ratio (carboxyl function of the carboxylic acid)/(carboxyl function of the thiolactic acid) is of 1.

[0203] For P2-P9, the molar equivalent ratio (hydroxyl functions of the polyol)/(carboxyl functions of the carboxylic acid and the thiolactic acid) is of 1.05.

[0204] 1.2.2. In One Step

[0205] Sulphur-containing polyester P10 is prepared in a four-necked round bottom flask equipped with a temperature probe, a stirrer shaft, a condenser, and a gas sparger, is charged of 1 mol of PG-4, 3.99 mol of oleic acid, 1.71 mol of thiolactic acid and 0.2 wt % of methanesulfonic acid based on the weight of the composition. The mixture is heated up to 170° C. under stirring, until the acid value is less than 15 mg KOH/g.

[0206] Then, the reaction mixture is allowed to cool down to room temperature.

[0207] The molar equivalent ratio (hydroxyl functions of the polyol)/(carboxyl function of the carboxylic acid) is of 1.5 and the molar equivalent ratio (carboxyl function of the carboxylic acid)/(carboxyl function of the thiolactic acid) is of 2.3.

[0208] The molar equivalent ratio (hydroxyl functions of the polyol)/(carboxyl functions of the carboxylic acid and the thiolactic acid) is of 1.05.

Example 2: Characteristics of Sulphur-Containing Polyesters According to the Invention

[0209] 2.1 Hydroxyl Value and Acid Value

[0210] Hydroxyl value (HV) is defined as the number of milligrams of potassium hydroxide required to neutralize the free acids taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups. This value was measured according to standards AOCS Cd 13-60.

[0211] Results are gathered in Table 2 below:

TABLE-US-00002 TABLE 2 Acid values and hydroxy values of sulphur-containing polyesters according to the invention AV (mg KOH/g) HV (mg KOH/g) P1 4.71 89.95 P2 4.25 52.99 P3 4.66 58.04 P4 5.47 73.70 P5 10.40 74.80 P6 14.70 82.70 P7 3.01 82.16 P8 9.96 84.16 P9 7.34 78.47 P10 9.06 72.22

[0212] 2.2 Kinematic Viscosities at 40° C.

[0213] Kinematic viscosities were assessed according to the standard ASTM D 445. Results are gathered in Table 3 below:

TABLE-US-00003 TABLE 3 Kinematic viscosities of sulphur-containing polyesters according to the invention Kinematic viscosity at 40° C. (mm.sup.2/s) P1 23.8 P2 53.5 P3 65.3 P4 207.5 P5 599.0 P6 182.2 P7 270.1 P8 297.0 P9 101.7 P10 170.5

[0214] Kinematic viscosity at 40° C. of sulphur-containing polyesters P1-P10 vary from 23.8 to 599 mm.sup.2/s. More particularly, P1-P4 and P6-P10 present a kinematic viscosity at 40° C. less than 300 mm.sup.2/s. Those low viscosities facilitate their implementation.

Example 3: Evaluation of Properties of the Sulphur-Containing Polyesters According to the Invention

[0215] 3.1. Preparation of Compositions According to the Invention and of a Comparative Composition

[0216] All the compositions were prepared at room temperature by mixing an additive and an oil using an overhead stirrer at 200 rpm to attain homogeneity.

[0217] Contents of each composition are described in Table 4 below:

TABLE-US-00004 TABLE 4 Contents of compositions 1-14 according to the invention and comparative compositions 1 and 2 Content Composition 1 5 wt %* P1 in naphthenic oil Composition 2 5 wt %* P1 in paraffinic oil Composition 3 5 wt %* P2 in naphthenic oil Composition 4 5 wt %* P2 in paraffinic oil Composition 5 5 wt %* P3 in naphthenic oil Composition 6 5 wt %* P4 in naphthenic oil Composition 7 5 wt %* P5 in naphthenic oil Composition 8 5 wt %* P6 in paraffinic oil Composition 9 5 wt %* P7 in naphthenic oil Composition 10 5 wt %* P8 in naphthenic oil Composition 11 5 wt %* P9 in paraffinic oil Composition 12 5 wt %* P10 in naphthenic oil Composition 13 5 wt %* P6 in TMPTO Composition 14 5 wt %* P6 in rapeseed oil Comparative composition 1 5 wt %* MCCP in naphthenic oil Comparative composition 2 5 wt %* MCCP in paraffinic oil *based on weight of the composition

[0218] 3.2. Friction Modifier Property of Sulphur-Containing Polyesters According to the Invention

[0219] For the evaluation of the friction modifier property, an Anton Paar MCR 302 coupled with a TPTD-200 tribometer was used.

[0220] A 12.7 mm stainless steel ball, immersed in a composition to test, is loaded against the face of a 10 mm diameter cylindrical steel pin and the ball is turning against the stationary cylindrical steel pin, where the friction resulting from the two metal surface contact is measured.

[0221] Coefficients of friction were measured as a function of the speed of rotation (1600-1 rpm) at a load of 10N, to establish a Stribeck curve represented in FIGS. 1 and 2.

[0222] Results show that coefficient of frictions of compositions 7 and 8 are much lower than those of corresponding non additivated oils. Moreover, lower coefficients of friction are obtained with compositions comprising the sulphur-containing polyesters of the invention than those of comparative compositions 1 and 2.

[0223] 3.3. Anti-Wear Property of Sulphur-Containing Polyesters According to the Invention

[0224] An Anton Paar Reichert Wear Tester RM2 instrument is used to evaluate the anti-wear property of compositions. During this test, a test roll presses against a revolving friction wheel which is semi immersed in a tested composition. A rotating speed of 960 rpm and the load of 14.71 N (1.5 kgf) are applied during the test. Results are gathered in Table 5 below.

TABLE-US-00005 TABLE 5 Reichert wear scar areas of mineral oils, composition according to the invention and comparative compositions Wear scar area (mm.sup.2) Naphthenic oil 37.07 Composition 1 7.42 Composition 3 10.14 Composition 6 11.31 Composition 9 12.06 Composition 10 11.23 Comparative composition 1 9.38 Paraffinic oil 35.96 Composition 2 6.40 Composition 4 9.24 Composition 8 8.92 Composition 11 10.09 Comparative composition 2 4.92

[0225] Anti-wear properties of compositions according to the invention are comparable to anti-wear properties of comparative compositions comprising a chlorinated compound, especially in naphthenic oil.

[0226] 3.4. Extreme Pressure Property of Sulphur-Containing Polyesters According to the Invention

[0227] Four balls method according to standard test ASTM D2783-2014, was used to determined extreme pressure property of sulphur-containing polyesters according to the invention.

[0228] The test was run by applying on 3 steel balls placed on a same plane and immersed in a composition or an oil, a load with a rotation at 1770 rpm for 10 s at room temperature, via a 4th steel ball placed at the intersection of the three other balls. The test is repeated at an increased load until welding occurs. Results obtained are gathered in Table 6 below:

TABLE-US-00006 TABLE 6 Weld points of mineral oils, composition according to the invention and comparative compositions Weld point (kg) Naphthenic oil 100 Composition 1 200 Composition 3 200 Composition 5 250 Composition 6 250 Composition 7 315 Composition 10 250 Composition 12 250 Comparative composition 1 200 Paraffinic oil 100 Composition 2 250 Composition 4 250 Composition 8 200 Composition 9 200 Comparative composition 2 200 Composition 13 200 Composition 14 200

[0229] Compositions according to the invention present good extreme pressure properties, as the weld point increase from 100 to at least 200 kg. Moreover, extreme pressure properties of sulphur-containing polyester according to the invention is at least as good as chlorinated additive.

[0230] 3.5. Corrosion Property of Sulphur-Containing Polyesters According to the Invention

[0231] To evaluate the degree to which the product of the invention will corrode copper-containing materials, copper corrosion test was performed according to ASTM D130.

[0232] The corrosiveness of each oil and composition was interpreted in accordance with the classification of the ASTM D130:

TABLE-US-00007 Classification Description Designation 1 a light orange, almost the same as freshly Slight polished strip tarnish b dark orange 2 a claret red Moderate b lavender tarnish c multicolored with lavender blue or silver, or both, overlaid on claret red d silvery e brassy or gold 3 a magenta overcast on brassy strip Dark b multicolored with red and green showing tarnish (peacock), but no grey 4 a transparent black, dark gray or brown with Corrosion peacock green barely showing b graphite or lusterless black c glossy or jet black

[0233] Results obtained are gathered in Table 7 below.

TABLE-US-00008 TABLE 7 Copper corrosion test results with naphtenic oil, compositions 1, 5, 9-11, and comparative composition 1 Classification after 3 h at 100° C. Naphtenic oil 1a Composition 1 2b Composition 5 1b Composition 9 1b Composition 10 2b Composition 11 1b Comparative composition 1 1b

[0234] Compositions according to the invention present low corrosivity, as only a slight to moderate layer of corrosion was formed over each copper strip. Results are comparable to comparative composition 1 comprising a chlorinated additive.