Method for producing polyester polyols and use thereof in polyurethane

Abstract

A polyester polyol of formula produced by a first polycondensation (a) of a sugar alcohol Z in C3 to C8 and two diacids Y and Y′ which are the same or different in C4 to C36, and a second polycondensation (b) of the product produced in (a) with two diols X and X′ which are the same or different in C2 to C12, the polymer including such a polyester polyol. Also, a method for producing the polyester polyols and the use thereof in foams, adhesives, coatings or elastomers of polyurethane or polyisocyanurate.

Claims

1. A polyester polyol having the general formula Rx-Ry-Rz-Ry′-Rx′, wherein: Rz is a C4 to C7 sugar alcohol, Ry and Ry′ are identical or different diesters having formula —OOC—C.sub.n—COO— with n between 2 and 10, and Rx and Rx′ are identical or different C2 to C12 monoalcohols.

2. The polyester polyol according to claim 1, wherein Rz is a C5 or C6 sugar alcohol.

3. The polyester polyol according to claim 1, wherein n is between 3 and 10.

4. The polyester polyol according to claim 1, wherein Rx and Rx′ are C3 to C8 monoalcohols.

5. A method for obtaining a polyester polyol according to claim 1, comprising the following steps: a) a step of polycondensation at a temperature between 110 and 200° C.: i. of a sugar alcohol Z in C4 to C7, ii. of two diacids Y and Y′ in C4 to C12 which are identical or different, iii. of two diols X and X′ in C2 to C12 which are identical or different, b) optionally, a step of neutralisation; wherein the step of polycondensation comprises a first polycondensation (a-1) of the sugar alcohol Z and of the diacids Y and Y′ and a second polycondensation (a-2) of the product obtained in the first polycondensation (a-1) with the diols X and X′.

6. A polymer comprising the polyester polyol according to claim 1.

7. A composition comprising the polyester polyol according to claim 1, or a polymer comprising said polyester polyol, the polymer being a polyurethane or a polyisocyanurate.

8. The composition according to claim 7, wherein the composition is a foam, an elastomer, an adhesive, a coating or a composition allowing for the obtaining of any one of the foam, elastomer, adhesive and coating after polymerisation.

9. The composition according to claim 7, further comprising a reaction catalyst and a polyisocyanate.

10. A method for obtaining a foam, a coating, an adhesive or a polyurethane or polyisocyanurate elastomer comprising: a step of obtaining a polyester polyol according to claim 1, a step of adding of at least one polyisocyanate and of at least one reaction catalyst, and a step of polymerisation.

11. A composition comprising the polymer of claim 6.

12. The composition according to claim 11, wherein the composition is a foam, an elastomer, an adhesive, a coating or a composition allowing for the obtaining of any one of the foam, elastomer, adhesive and coating after polymerisation.

13. The composition according to claim 11, further comprising a reaction catalyst and a polyisocyanate.

14. A method for obtaining a foam, a coating, an adhesive or a polyurethane or polyisocyanurate elastomer comprising: a step of obtaining a polymer according to claim 6, a step of adding of at least one polyisocyanate and of at least one reaction catalyst, and a step of polymerisation.

15. The method according to claim 5, comprising the following step: a) a step of polycondensation at a temperature between 110 and 200° C. for 5 to 10 hours: i. of a sugar alcohol Z in C5 or C6, ii. of two diacids Y and Y′ in C5 to C12 which are identical or different, iii. of two diols X and X′ in C3 to C8 which are identical or different.

16. The polymer according to claim 6, the polymer being a polyurethane or a polyisocyanurate.

17. The polyester polyol according to claim 1, wherein n is between 4 and 10.

18. The polyester polyol according to claim 1, wherein Rx and Rx′ are C4 monoalcohols.

19. The method according to claim 5, wherein the sugar alcohol Z is chosen from erythritol, arabitol, ribitol, xylitol, sorbitol, dulcitol, mannitol, and volemitol.

20. The method according to claim 5, wherein the diacids Y and Y′ are independently chosen from butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, and mixtures thereof.

21. The method according to claim 5, wherein the diols X and X′ are independently chosen from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, and mixtures thereof.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1a corresponds to the spectra of NMR 13C of the bi-acidic reaction intermediate common to all of the polyester polyols where Y═Y′=adipic acid.

(2) FIG. 1b corresponds to the spectrum of NMR 13C of bis (1,2 ethanediol)-sorbitol diadipate.

(3) FIG. 1c corresponds to the spectrum of NMR 13C bis(1,3-propanediol)-sorbitol diadipate.

(4) FIG. 1d corresponds to the spectrum of NMR 13C bis(1,4-butanediol)-sorbitol diadipate.

(5) FIG. 2a corresponds to the spectrum of NMR 13C bis (1,6 hexanediol)-sorbitol diadipate.

(6) FIG. 2b corresponds to the spectrum of NMR 13C bis (1,8 octanediol)-sorbitol diadipate.

(7) FIG. 2c corresponds to the spectrum of NMR 13C bis (1,10 decanediol)-sorbitol diadipate.

(8) FIG. 2d corresponds to the spectrum of NMR 13C bis (1,12 dodecanediol)-sorbitol diadipate.

EXAMPLES

Example 1

(9) 1.1 Equipment and Methods:

(10) The D-sorbitol commercialised by TEREOS SYRAL (sorbitol sup. 98%, water less 0.5%, reducing sugars less 0.1%); 1,4 butanediol (99%), 1,10 decanediol, 1,2-ethanediol, 1,6-hexanediol, 1,10-octanediol, 1,12-dodecanediol are commercialised by the company SIGMA ALDRICH; 1,8 octanediol (98%) and Glycerol are commercialised by the company FLUKA; adipic acid (99%) commercialised by the company ACROS ORGANICS; 1,3-propanediol by ALFA AESAR and succinic acid (Technical grade) commercialised by the company BIOAMBERT.

(11) The sorbitol and the adipic acid are dried in an oven at reduced pressure at 45° C. for one night then are stored in a vacuum desiccator. The other products are used as is.

Synthesis of bis(1,2 ethanediol)-sorbitol diadipate (bis(2-hydroxylethyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1, 6-diyl) diadipate)

(12) In a three-neck flask (three necks with lapping 29:32) of 250 mL, 10.00 g of sorbitol (0.0549 mol) and 16.03 g of adipic acid (0.11 mol) are introduced. The entry of argon is fixed on the first neck of the three-neck flask, on the second (central neck) is fixed the complete short column distillation system. Finally the third and last neck is plugged using a plug of the septum type that is perforable in order to allow for future injections into the reaction medium. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rotations per minute (rpm) which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 6.83 g of 1,2-ethanediol (0.11 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h for a total reaction time of 9 h. At 8 h00 and 9 h00 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,3-propanediol)-sorbitol diadipate (bis(3-hydroxypropyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1, 6-diyl) diadipate)

(13) In a 250 mL three-neck flask 2.00 g of sorbitol (0.0110 mol), 3.2 g of adipic acid (0.0219 mol) and a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 1.67 g of 1,3-propanediol (0.0219 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,4-butanediol)-sorbitol diadipate(bis(4-hydroxybutyl)O,O′-((2R,3R,4R,5S)-2, 3, 4, 5-tetrahydroxyhexane-1, 6-diyl) diadipate)

(14) In a 250 mL three-neck flask, 10.00 g of sorbitol (0.0549 mol) and 16.03 g of adipic acid (0.11 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 9.98 g of 1,4-butanediol (0.11 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,6 hexanediol)-sorbitol diadipate (bis(6-hydroxyhexyl)O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1, 6-diyl) diadipate)

(15) In a 250 mL three-neck flask, 2.00 g of sorbitol (0.0110 mol) and 3.2 g of adipic acid (0.0219 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 9.98 g of 1,6hexanediol (0.0219 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,8 octanediol)-sorbitol diadipate (bis(8-hydroxyoctyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-diyl) diadipate)

(16) In a 250 mL three-neck flask are introduced 1.000 g of sorbitol (0.00549 mol), 1.603 g of adipic acid (0.01098 mol) as well as a magnetic stirrer. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring at 100 rpm then at 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 1.605 g of 1,8-octanediol (0.01098 mol) is injected then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,10 decanediol)-sorbitol diadipate (bis(10-hydroxydecyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-diyl) diadipate)

(17) In a 250 mL three-neck flask, 1.000 g of sorbitol (0.00549 mol) and 1.603 g of adipic acid (0.01098 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring at 100 rpm then at 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 1.910 g of 1,10-octanediol (0.01098 mol) is injected then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,12 dodecanediol)-sorbitol diadipate (bis(12-hydroxydodecyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-diyl) diadipate)

(18) In a 250 mL three-neck flask, 5.00 g of sorbitol (0.0274 mol) and 8.015 g of adipic acid (0.0549 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 11.089 g of 1,12-dodecanediol (0.0549 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,4 butanediol)-sorbitol disuccinate (bis(4-hydroxybutyl) O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-diyl) disuccinate)

(19) In a 250 mL three-neck flask, 10.00 g of sorbitol (0.0549 mol) and 12.95 g of succinic acid (0.11 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 9.98 g of 1,4-butanediol (0.11 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of sorbitol-diadipate-disorbitol (2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl ((2R,3R,4R,5S)-2,3,4,5-tetrahydroxy-6-((6-oxo-6-(((2R,3R,4R,5S)-2,3,4,5,6-pentahydroxyhexyl)oxy) hexanoyl)oxy)hexyl) adipate

(20) In a 250 mL three-neck flask, 10.00 g of sorbitol (0.0549 mol) and 16.03 g of adipic acid (0.11 mol) as well as a magnetic stirrer are introduced. The mounting of the three-neck flask and of the distillation system is carried out as hereinabove. The reaction medium is brought to 150° C. under inert atmosphere (argon) and under a low stirring set to 100 rpm which will be increased to 350 rpm once the reaction medium is entirely viscous. After three hours of reaction, 20.0 g of sorbitol (0.11 mol) are injected using a 12 mL syringe then the reaction is continued for 6 h which is a total reaction time of 9 h. At 3 h30 and 6 h30 of reaction two passages under vacuum of respectively 30 seconds and 1 minute are carried out in order to draw the water produced by the polycondensation reaction. After each passage in the vacuum, the reaction medium is brought under inert atmosphere and to atmospheric pressure.

Synthesis of bis(1,4-butanediol)-sorbitol diadipate (bis(4-hydroxybutyl)O,O′-((2R,3R,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-diyl) diadipate) and 1,4-butanediol-sorbitol adipate modified in reactor

(21) The reaction is carried out in a stainless steel sealed reactor equipped with a U-shaped stirring blade, with a Dean Stark having an outlet at the top of the condenser in order to connect thereto a vacuum pump and a low outlet in order to recover the condensates, an inlet and an outlet for inert gas. Into the reactor are introduced in the powder state sorbitol and adipic acid in a molar ratio of 1/2 (sorbitol/adipic acid). The reactor is placed under inert atmosphere then is turned on for heating. When the temperature reaches 100° C., the stirring is progressively started up to 170 rpm. When the temperature reached 150° C., the reaction is started and continued for 3 h. After 3 h, 1,4 butanediol (called diol in what follows) is introduced into the reactor in a molar ratio (1,4 butanediol/sorbitol) of 2.2/1. When the temperature of the reaction medium returns to 150° C. (stirring still maintained at 170 rpm, inert atmosphere) the diol is added after 2 h30 then a passage under partial vacuum is carried out for a duration of one minute then the atmospheric pressure is brought under inert atmosphere. 4 h30 after the adding of diols, another partial vacuum flush is carried out for 2 minutes then the atmospheric pressure if brought under inert atmosphere. 6 h15 minutes after the introduction of the diol (which is a total reaction time of 9 h15 min at 150° C.), the reactor is stopped and the reaction product is recovered hot in order to have a minimum of loss during the transfer of the material from the reactor to the packaging of the product.

(22) 1.2 Preparation of Samples for Measuring the Hydroxyl Index (HOI)

(23) The measuring of the hydroxyl index was carried out according to the standard ASTM 4274-99 wherein the calorimetric titration was replaced with a pH-metric titration. More particularly, the measurement was carried out in the following way. In a 250 mL one-neck flask, about 1 g of sample us weighed to the nearest 1 mg.

(24) 20 mL of a reactive solution of phthalic anhydride 1N in the pyridine are added using the 20 mL gauged pipette then the system is set to reflux for 45 min at 130° C. After having cooled the mixture, 10 mL of pyridine are introduced from the top of the coolant then the contents of the flask is transferred into a 150 mL tall beaker for titration. Then 20 mL of pyridine and 30 mL of water are added before titrating via potash in the water at 1N using the automatic titrator.

(25) 1.3 Preparation of Samples for the NMR.sup.31P Analysis

(26) About 10-15 mg of polyol are introduced into a 4 mL flask to which is added 400 μL of solvent (pyridine/CDCl.sub.3 ratio 1.6/1, v/v), the mixture is left under magnetic stirring for 2 min. Then are added 100 μL of a standard solution (1 mmol of N-hydroxylnaphthalimide in 10 mL of solvent and 50 mg of Cr(III) acetyl acetonate) and 100 μL of phosphorous reagent (2-chloro-1,2,3-dioxaphospholane). The whole is left under magnetic stirring at ambient temperature for 2 h before the analysis .sup.31P NMR.

(27) 1.4 Neutralisation of the Polyols with a Sorbitol Base

(28) As the polycondensation reaction during the synthesis of the various polyols does not make it possible to reach conversion rates of 100% residual traces of unreacted acid are then found in the final product. In order to overcome this, three types of neutralisation were considered. Two conventional neutralisations of the acido-basic type with soda or with potash in order to neutralise the acid residue via a simple acido-base reaction and a neutralisation via hexan-1-ol or an esterification via a mono-alcohol.

(29) a) Neutralisation via soda (NaOH)

(30) In a 250 mL single-neck flask are introduced: 50.4 g of 1,4 butanediol-sorbitol adipate, 2.065 g of NaOH corresponding to the residual acidity to be neutralised (determined by titration) as well as 60 mL of ethanol in order to fluidify the medium. The flask is provided with a bulb condenser and the medium is heated to 60° C. The reaction time is one hour. The reaction product is then distilled with a distillation bridge in order to extract the ethanol and recover the neutralised initial polyol.

(31) b) Neutralisation via potash (KOH)

(32) In a 250 mL single-neck flask are introduced: 49.9 g of 1,4 butanediol-sorbitol adipate, 2.89 g of KOH corresponding to the residual acidity to be neutralised (determined by titration) as well as 60 mL of ethanol in order to fluidify the medium. The flask is provided with a bulb condenser and the medium is heated to 60° C. The reaction time is one hour. The reaction product is then distilled with a distillation bridge in order to extract the ethanol and recover the neutralised initial polyol.

(33) c) Neutralisation with hexanol

(34) In a 250 mL single-neck flask are introduced: about 23.3 g of 1,4 butanediol-sorbitol adipate, as well as 170 mL of hexanol. The flask is provided with a distillation bridge which allows for the reflux of the hexanol and the elimination of the water produced by the reaction then the medium is brought to reflux for one night. The reaction product is then vacuum distilled at 130° C. with a distillation bridge.

(35) 1.5 Characterisation of the Products Obtained

(36) The molar masses and the polydispersity indexes were determined by steric exclusion chromatographies in the chloroform by using a Shimadzu liquid chromatography. The columns used are PLGel Mixed—This PLGeL of 100A. A refraction index differential detector is used. Chloroform is used as an eluent at a flow rate of 0.8 ml/min. The device is calibrated with linear polystyrene standards with molar masses ranging from 162 to 1,650,000 g/mol.

(37) The calculations of the mean molecular weights and of the polymolecularity indexes in RI or UV detection are carried out according to a calibration curve with polystyrene or polymethylmethacrylate standards.

(38) The thermogravimetric analyses (ATG) were carried out on a TGA Q5000 from TA Instrument and the analyses were carried out using the Universal Analysis 2000 software. The heat ramp is set to 10° C./min from 25° C. to 600° C. under a constant flow of reconstituted air or of helium at 25 mL/min.

(39) The differential scanning calorimetry analyses (DSC) are carried out using a DSC Q200 from TA Instrument. The heat ramps are set to 10° C./min and the cooling ramps at 5° C./min between −85° C. and 160° C. under a flow of N.sub.2 adjusted to 25 mL/min. The data is analysed using the Universal Analysis 2000 software.

(40) The return titrations are carried out using an automatic TitroLine 7000 titrator supplied by SI Analitics. The titrating solution used is obtained from volume concentrates (Fixanal) supplied by Fluka Analytical.

(41) The magnetic resonance of the phosphorous (.sup.31P) was carried out on a Bruker advance 3 400 MHz spectrometer. The spectral window is centred on 22677 Hz and is 100 ppm wide (particles per million). The relaxation time is set to 2 seconds and the number of scans recorded is 128.

(42) The magnetic resonance of the proton was carried out on the same spectrometer with a number of scans of 128.

(43) The infrared spectroscopy was carried out with a Nicolet 380 Fourier transform infrared spectrometer (Thermo Electron Corporation). The device is equipped with a module for analysing the attenuated total reflection (ATR) on diamond with a resolution of 4 cm.sup.−1, 64 analysis scans per sample with an ATR correction proper to the diamond are carried out.

(44) The rheological measurements were taken on an Anton Paar Physica MCR 301 rheometer with a plane cone geometry of 25 mm in diameter and a Peltier effect enclosure. The analysis program is comprised of three steps:

(45) 1: a temperature ramp from 0° C. to 50° C. at 0.1° C./min and a constant shear rate of 10 s.sup.−1

(46) 2: a scanning at a shear rate ranging from 0.001 s.sup.−1 to 100 s.sup.−1 at a constant temperature of 20° C.

(47) 3: a scanning at a shear rate ranging from 0.001 s.sup.−1 to 100 s.sup.−1 at a constant temperature of 25° C.

Example 2

Results

(48) 2.1 Analysis of the Structure of the Products Obtained and Yields

(49) The synthesis methods implemented made it possible to obtain the following 9 molecules:

(50) bis(1,4 butanediol)-sorbitol disuccinate

(51) sorbitol-diadipate-sorbitol

(52) bis(1,2 ethanediol)-sorbitol diadipate

(53) bis(1,3 propanediol)-sorbitol diadipate

(54) bis(1,4 butanediol)-sorbitol diadipate

(55) bis(1,6 hexanediol)-sorbitol diadipate

(56) bis(1,8 octanediol)-sorbitol diadipate

(57) bis(1,10 decanediol)-sorbitol diadipate

(58) bis(1,12 dodecanediol)-sorbitol diadipate

(59) The method according to the invention makes it possible to obtain the products hereinabove with yields between 80 and 90%. The synthesised products have different macroscopic aspects for example:

(60) bis(1,2 ethanediol)-sorbitol diadipate: slightly yellow viscous liquid

(61) bis(1,3 propanediol)-sorbitol diadipate: slightly yellow viscous liquid

(62) bis(1,4 butanediol)-sorbitol diadipate: slightly yellow viscous liquid

(63) bis(1,6 hexanediol)-sorbitol diadipate: yellowish solid gel

(64) bis(1,8 octanediol)-sorbitol diadipate: orangish wax

(65) bis(1,10 decanediol)-sorbitol diadipate: whitish wax

(66) bis(1,12 dodecanediol)-sorbitol diadipate: beige wax

(67) 2.1.1 Analysis in Fourier Transform Infrared Spectroscopy (FT-IR)

(68) The bis(1,2 ethanediol)-sorbitol diadipate, bis(1,3 propanediol)-sorbitol diadipate, bis(1,4-butanediol)-sorbitol diadipate, bis(1,6 hexanediol)-sorbitol diadipate, bis(1,8 octanediol)-sorbitol diadipate, bis(1,10 decanediol)-sorbitol diadipate, bis(1,12 dodecanediol)-sorbitol diadipate, were analysed by FT-IR.

(69) For each product the characteristic absorption bands of the hydroxyl functions (wide band at 3999 cm.sup.−1), carbon chains (absorption band at 2940 cm.sup.−1) and the band that corresponds to the ester functions (thin and intense band at 1725 cm.sup.−1) were observed. The presence of these absorption bands, more particularly those of the ester function confirms that the esterification function did indeed take place and that the structure of the polyols is indeed of the polyester polyol type carrying hydroxyl functions required for the formulation of PUR and PIR foam.

(70) No reaction co-product comes from the FT-IR analysis, the residual acid functions cannot be seen in FT-IR as they are confounded in the bottom of the characteristic absorption band of the ester functions. Compared to the methods of prior art, the method of this invention does not induce or induces very little cyclisation of the sorbitol. Indeed, no absorption band at 1068 cm.sup.−1 characteristic of the cyclisation of the sorbitol is observed. It is however possible that these cyclisation phenomena are present as a minority and therefore undetectable because less than the detection limit of the method used, or due to the superposition of the signal concerned among other absorption bands in the zone between 1500 and 940 cm.sup.−1.

(71) 2.1.2 Analysis of the Results via NMR of the Proton (NMR.sup.−1H)

(72) The magnetic resonance analysis of the proton of all of the synthesised polyols allows the progress of the reaction to be followed by following the change in the peak corresponding to the proton in a of the ester bond formed at 2.3 ppm and that of the proton in a of the acid function consumed at 2.2 ppm. This makes it possible to determine the various characteristics times of the esterification reactions at play. During the first portion of the synthesis when the relative intensity of the peak corresponding to the acid function has decreased by half, the reaction intermediate sought is obtained with a yield of 100% and corresponds to the moment of injection of the terminal diol. At the end of the reaction, the ratio of the two peaks provides information on the state of progress of the reaction between the reaction intermediate and the diol. The maximum progress reached is 85%.

(73) 2.1.3 Analysis of the Results via NMR of the Carbon (NMR.sup.−13C)

(74) The magnetic resonance analysis of the carbon makes it possible to assign all of the carbon atoms present in the molecule to a chemical shift. This analysis makes it possible to determine the carbon skeleton of the various synthesised polyols. The ranges of chemical shifts used as a reference for the analysis of the various spectra are as follows:

(75) TABLE-US-00001 TABLE 1 Chemical shifts of the various carbons present in the polyester polyols Chemical shifts in ppm Corresponding carbon 23 to 26 Non-functionalised carbon chains 27 to 35 Carbon chains in the vicinity of ester or alcohol functions 60 to 62 Carbon carrying a terminal primary hydroxyl function 62 to 64 Carbon in α of the ester on the sorbitol chain 64 to 75 Carbon chain of the sorbitol (low signal) 172 to 173 Carbonyl

(76) Using this data, the chemical structures of the synthesised polyester polyols were determined by the analysis of the spectra obtained (FIGS. 1a to 1d and FIGS. 2a to 2d).

(77) 2.1.4 Analysis of the Results via NMR of the Phosphorus 31

(78) The magnetic resonance analysis of the phosphorus 31 of all of the synthesised polyester polyols makes it possible to precisely determine the quantities of residual acid functions in the polyester polyols, as well as the quantity of total hydroxyl functions by overcoming the steric hindrance.

(79) TABLE-US-00002 TABLE 2 Hydroxyl and acid indexes determined by NMR-.sup.31P analyses Mmol.g.sup.−1 of Mmol.g.sup.−1 of Polyol OH HOI COOH IA 1 10.37 581.8 0.60 33.7 2 11.21 628.9 0.40 22.4 3 10.52 590.2 0.42 48 4 9.03 506.6 0.33 18.5 5 8.24 462.3 0.4 22.4 6 7.84 439.8 0.22 12.3 7 8.7 488 0.20 11.22

(80) 2.1.5 Structure of the Molecules Obtained

(81) ##STR00003##

(82) The carried-out characterisations confirm that the synthesised polyester polyols have a well-defined architecture that is in accordance with the two-step operating protocols used aiming such structure of the molecules. The chemical structures of (a) bis(1,2 ethanediol)-sorbitol diadipate (526 g/mol), (b) bis(1,3propanediol)-sorbitol diadipate (554 g/mol), (c) bis(1,4-butanediol)-sorbitol diadipate (582 g/mol), (d) bis(1,6 hexanediol)-sorbitol diadipate (638 g/mol), (e) bis(1,8 octanediol)-sorbitol diadipate (694 g/mol), (f) bis(1,10 decanediol)-sorbitol diadipate (750 g/mol), (g) bis(1,12 dodecanediol)-sorbitol diadipate (806 g/mol), (h) bis(1,4 butanediol)-sorbitol disuccinate (526 g/mol), (i) sorbitol-diadipate-disorbitol (766 g/mol). The chemical structures of the polyols obtained are found hereinbelow with the general formula C.sub.aH.sub.bO.sub.c with 22≤a≤42, 38≤b≤78, 14≤c≤22.

(83) 2.2 Characterisation of the Properties of the Polyester Polyols

(84) 2.2.1 DSC Analysis

(85) Thermal characterisations of the DSC type make it possible to determine the crystallinity or not of the polyester polyol obtained by measuring a melting temperature (Tf) and a glass transition temperature (Tg). Having amorphous polyester polyols (absence of Tf) with a low Tg (lower than ambient temperature) is particularly advantageous as this ensures that the polyester polyols will not undergo any change in state during the formulation.

(86) TABLE-US-00003 TABLE 3 Glass transition (Tg) and melting (Tf) temperatures of the polyols Nature of the polyol Tg (° C.) Tf (° C.) bis(1,2 ethanediol)-sorbitol diadipate −25 / bis(1,3 propanediol)-sorbitol diadipate −27 / bis(1,4-butanediol)-sorbitol diadipate −48 / bis(1,6 hexanediol)-sorbitol diadipate −53 / bis(1,8 octaediol)-sorbitol diadipate / 23 bis(1,10 decanediol)-sorbitol diadipate −75  0-50 bis(1,12 dodecanediol)-sorbitol diadipate / 30-40 bis(1,4 butanediol)-sorbitol disuccinate −40 / sorbitol- diadipate- sorbitol −10 /

(87) Thus, among all of the synthesised molecules only three have a melting temperature and are therefore in crystalline form: 1,8 octanediol-sorbitol adipate, 1,10 decanediol-sorbitol adipate and bis(1.12 dodecanediol)-sorbitol diadipate. The other polyols have Tg at temperatures less than 0° C. (see table 3).

(88) The low Tg and the absence of crystallisation and melting temperatures for the following three polyols: bis(1.2 ethanediol)-sorbitol-diadipate, bis(1.3 propanediol)-sorbitol-diadipate and bis(1.4 butanediol)-sorbitol-diadipate make it possible to affirm that these polyols will remain viscous liquids at ambient temperature and therefore in particular at the temperatures of use of the polyurethane foams, the preferred application of the invention (20-25° C.). The other polyols do not have a Tf namely bis (1,6 hexanediol)-sorbitol diadipate, bis (1,4 butanediol)-sorbitol disuccinate and sorbitol-diadipate-sorbitol. They will remain viscous (waxy aspect) at ambient temperature (20-25° C.). The three polyols that have a Tf are both solid at ambient temperature, which indicates a use in an application other than foaming such as for example coating, adhesives or elastomers are recommended. Indeed, during the foaming operations, the polyol must be able to be mixed with a polyisocyanate at 20-30° C., crystalline products with melting temperatures greater than 15° C. are not recommended. Thus, bis(1.2 ethanediol)-sorbitol-diadipate, bis(1.3 propanediol)-sorbitol-diadipate and bis(1.4 butanediol)-sorbitol-diadipate are particularly advantageous in a large panel of applications and more particularly foaming. The other polyester polyols can be intended for applications of the elastomer, adhesive or coating type.

(89) 2.2.2 Thermogravimetric Analysis (ATG)

(90) ATG makes it possible to determine the steps of the loss of mass and degradation of the polyester polyols.

(91) The analysis of the results shows a degradation in two steps. Thus, all of the polyols analysed are degraded in two steps (see table 4).

(92) TABLE-US-00004 TABLE 4 Degradation temperatures of the polyols 1st degradation % 2nd T° C. wt of degradation Nature of the polyol range loss T° C. range bis(1,2 ethanediol)-sorbitol diadipate 50-130 7 150-450 bis(1,3 propanediol)-sorbitol diadipate 50-135 8 135-450 bis(1,4-butanediol)-sorbitol diadipate 40-130 7 130-450 bis(1,6 hexanediol)-sorbitol diadipate 40-162 11 162-450 bis(1,8 octaediol)-sorbitol diadipate 40-175 12 175-500 bis(1,10 decanediol)-sorbitol diadipate 40-200 16 200-450 bis(1,12 dodecanediol)-sorbitol diadipate 40-210 19 210-475 bis(1,4 butanediol)-sorbitol disuccinate 40-160 9 160-475 sorbitol- diadipate- sorbitol 40-125 4 125-500

(93) During the formulation of polyurethane foams, the reaction at play is exothermic and the reaction medium reaches temperatures of 100° C. during the method. The polyester polyols used must therefore be stable up to 100° C.

(94) The first step at about 100° C. corresponds to a loss of mass relative to the loss of residual water in the form of vapour and to the loss still in the form of residual monomer vapour that did not react during the synthesis of the molecule. The loss of these small molecules is not a disadvantage for the formulation of polyurethane foams since they are present in small quantities and are extremely reactive with the isocyanates used in the formulation of polyurethane foams. They would therefore have reacted without incident on the rest of the method before evaporation before the reaction medium reaches 100° C.

(95) The second degradation corresponds to the degradation of the polyester polyol. The degradation mostly described in literature is the scission of the chain via the atom of hydrogen in β position of the ester bond, or α (less substantial phenomenon). There will also be intramolecular reactions (backbiting) resulting in cyclisations of chains or in the cyclisation of molecules (coming from a first degradation for example) etc. This corresponds to temperatures at which the polyester polyol will be degraded and lose its properties. Consequently, this temperature is indicative of the stability of the product obtained for these future uses.

(96) All of the synthesised polyester polyols are stable beyond 100° C., they can therefore all be used for the formulation of a foam, of an elastomer, of an adhesive or of a coating with regards to their thermal properties.

(97) 2.2.3 Rheological Analysis of the Obtained Products

(98) The rheological studies (table 5) make it possible to determine the viscosity of the synthesised polyols as a function of the temperature and the Newtonian nature or not thereof according to the shear rate.

(99) TABLE-US-00005 TABLE 5 Rheological study Viscosity according to the Viscosity according to shear rate at 20° C. the shear rate at 25° C. Viscosity Type of Viscosity Type of Polyol (Pa.S) fluid (Pa.S) fluid bis(1,3 125.5 ± 1.7  Newtonian 68.2 ± 0.5 Newtonian propanediol))sorbitol diadipate bis(1,4 butanediol) 44.6 ± 1.2 Newtonian 24.3 ± 0.2 Newtonian sorbitol diadipate bis(1,6 hexanediol)- 48.7 ± 1.2 Newtonian 27.16 ± 1.7  Newtonian sorbitol diadipate bis(1,4 butanediol)  5.3 ± 0.4 Newtonian  3.4 ± 0.2 Newtonian sorbitol diadipate modified glycerol bis(1,4 butanediol)- 12.2 ± 1.5 Newtonian  7.3 ± 0.5 Newtonian sorbitol diadipate modified ratio 2.1 to 1.4 BDO

(100) These results show that the products obtained namely bis(1,4 butanediol)-sorbitol-diadipate, bis(1,6 hexanediol)-sorbitol-diadipate and bis(1,4 butanediol)-sorbitol-diadipate modified glycerol and ratio 2.1 to 1,4 BDO have particularly advantageous characteristics for a use in all of the applications that conventionally use petroleum-sourced products such as foams, elastomers, adhesives or polyurethane coatings due to their sufficiently low viscosity (liquid nature) that allows them to be mixed at ambient temperature with the other components of the formulation. Bis(1,3 propanediol)-sorbitol diadipate has a high viscosity at 20° C., however, its drop in viscosity at 25° C. could allow for the use of this polyester polyol at this temperature in such formulations. The other polyester polyols were not subjected to viscosity analyses at 20° C. and 25° C. because they are waxy (solid) at these temperatures (see table 3) which makes their use in the formulation of polyurethane foams less interesting but has no incidence for the formulations of elastomers, adhesives or coatings since the mixing of the formulation can be carried out at a temperature that is higher than the ambient temperature.

(101) 2.2.4 Analysis of the Hydroxyl Index (HOI)

(102) The measurement of the hydroxyl index is used in particular for the elaboration of polyurethane foams. It makes it possible to evaluate the portion of isocyanate in the formulation of polyurethane foam.

(103) The synthesis of polyols comprising many hydroxyl groups of a different nature (primary and secondary) makes the titration difficult in terms of the steric hindrance for the secondary hydroxyl groups placed side by side on the sorbitol groups. Thus the hydroxyl indexes (HOI) presented in table 6 reflect the number of hydroxyls that can be accessed and taken into account for the formulation of polyurethane foam.

(104) TABLE-US-00006 TABLE 6 HOI of the synthesised polyols Nature of the polyol HOI (mg KOH/g) bis(1,4 butanediol)-sorbitol disuccinate 409 sorbitol-diadipate-sorbitol 692 bis(1,2 ethanediol)-sorbitol diadipate 533 bis(1,3 propanediol)-sorbitol diadipate 437 bis(1,4 butanediol)-sorbitol diadipate 400 bis(1,6 hexanediol)-sorbitol diadipate 415 bis(1,8 octaediol)-sorbitol diadipate 355 bis(1,10 decanediol)-sorbitol diadipate 326 bis(1,12 dodecanediol)-sorbitol diadipate 311

(105) The ranges of hydroxyl indexes sought by a manufacturer of foam depends on the type of foams (PUR, PIR, etc.) and on the number of polyols introduced into the formulation. In general, for a rigid foam, the range extends from 100 to 700 mg KOH/g. In the case of a foam of the PUR type the range of the hydroxyl index (HOI) that allows for the obtaining of a crosslinked three-dimensional network is between 300 and 700 mg KOH/g while for a network of the PIR type, the range of HOI has to be between 100 and 500 mg KOH/g. Thus, all of the polyester polyols have hydroxyl indexes that allow them to be used in PUR and PIR formulation.

(106) 2.2.5 Acid Titration of the Polyols

(107) The acid titration of the polyols incorporated into rigid polyurethanes foams is used in the formulation of these foams because the residual acid functions of the polyols polyesters are able to inhibit the catalysts used during the formulation of rigid polyurethane foams if the quantity thereof is excessive. The steps of titration and the three types of neutralisations were tested on bis(1,4 butanediol)-sorbitol diadipate because all of the preceding characterisations make it the polyester polyol that is most suitable for the formulation of polyurethane foams in particular rigid polyurethane foams.

(108) Titration before and after neutralisation makes it possible to judge the effectiveness of the latter. The step of neutralisation makes it possible to decrease the acid index by four and even by ten in optimum conditions.

(109) Various points will be noted during the neutralisations with the bases. With soda, the final polyester polyol is whitish while with potash, it is possible to extract a solid acido-basic precipitate and the aspect of the polyester polyol has not changed. The precipitates can always be condensed via centrifugation, but the neutralisation with potash has a certain advantage by facilitating the removal of the potash/acid complex that precipitates as agglomerates of a larger size than those of the soda.

(110) TABLE-US-00007 TABLE 7 Acidity index before and after neutralisation Neutralised Neutralised Neutralised After synthesis NaOH KOH hexanol Acid index 59 ± 2.3 8.3 ± 0.4 15.9 ± 1.6 24.2 ± 2 (mg KOH/g)

(111) The acidity index of the polyester polyol is evaluated before and after neutralisation. All of the results for bis(1,4 butanediol)-sorbitol diadipate are present in the table 7. The acidity index corresponds to the number of mg of KOH required to neutralise all of the carboxylic acid groups present in one gram of a polyester polyol. The acidity index can be determined by colorimetric dosage with methylene blue by using a potash solution at 0.1 mol/L in the methanol.

(112) The three types of neutralisation make it possible to substantially lower the acidity index of the polyester polyol. This neutralisation allows for the obtaining of a formulation of rigid polyurethane foam of very good quality.

Example 3

Formulation of Polyurethane Foams

(113) Polyurethane foams were obtained by using polyester polyols with a base of bis(1,4 butanediol)-sorbitol-diadipate and neutralised bis(1,4 butanediol)-sorbitol-diadipate. A premix containing the polyol and the various additives and expansion gas is prepared then the necessary quantity of polymeric diisocyante (pMDI) is added thereto (see table 8). The premix is obtained by a successive adding of components between which a step of homogenisation is carried out.

(114) TABLE-US-00008 TABLE 8 Formulation of rigid PUR foams KOH PUR 2 parts PUR non Cat. distilled PUR PUR Control neut. amine Hexanol NaOH Hexanol Supplier Reference PUR polyol Neut. Neut. Neut. Neut. 114.4 115.0 115.0 115.0 115. 115.0 pMDI 190.14 147.38 147.29 147.29 147.29 147.29 Control polyol 100.00 Polyol sorbitol base 100 Polyol sorbitol base neut. 100.00 NaOH Polyol sorbitol base neut. 100.00 KOH Polyol sorbitol base neut. 100.00 Hexanol Polyol sorbitol base neut. 100.00 distilled hexanol Water 1.66 1.6 1.60 1.60 1.60 1.60 Polyether polysiloxane 2.50 2.5 2.56 2.56 2.56 2.50 B1048 surfactant Catalyst: 2.35 1.7 2.00 2.06 2.06 2.11 Dimethylcyclohexylamine Flame retardant: TCPP 10.06 10 10.00 10.00 10.0 10.05 Swelling agent: Isopentane 15.37 11.92 13.08 13.52 13.9 15.73 TOTAL 322.0 275.10 276.53 277.03 277.5 279.28

(115) In the framework of formulations of rigid polyurethane foams (PUR) four tests were conducted: an industrial control (standard polyether of functionality 3.3 and a hydroxyl index of 585 mg KOH/g), a formulation with the polyester polyol with a base of 1.4 butanediol-sorbitol-adipate neutralised with KOH, then NaOH and neutralised with hexanol. Indeed, this polyester polyol has the best viscosity at ambient temperature and a low production cost (inexpensive monomers and bio-sourced or bio-sourceable) for the formulation of PUR foams.

(116) The premix formulations required to carry out the measurements of the characteristic times are expressed as a number of parts (table 8). To the premix is then added the quantity of polyisocyanate (type 4,4 polymeric MDI) desired (table 8).

(117) The characteristic times for the obtaining of a foam are measured namely the time for cream, string and tack-free as well as the height of the foam (table 9).

(118) TABLE-US-00009 TABLE 9 Characteristics of the foam obtained Neut. With 2 PUR parts PUR non KOH distilled PUR PUR Characteristic Control neut. Catalyst Hexanol NaOH Hexanol times in s PUR polyol amine Neut. Neut. Neut. Cream 10 75 15 50 14 45 String 39 420 70 163 73 203 Tack-free 60 1500 115 299 80 346 foam height 26.1 5 23.7 21.8 23.4 22.6

(119) The characteristic times obtained with the polyester polyols neutralised with potash and with soda are satisfactory, in the case of polyester polyols neutralised with hexanol the times are not as advantageous. Thus, the use of the neutralised polyester polyol, allows in comparison to non-neutralised polyester polyols, for the observation of a better reaction kinematics (shorter) and a foam height that is particularly advantageous, equivalent to non-bio-sourced products (control PUR). It is therefore recommended to use a neutralised version of the polyester polyol for the formulation of rigid polyurethane foams.

(120) Using a polyester polyol with a neutralised sorbitol base, it is therefore possible to formulate a polyurethane foam with kinematic characteristics that are similar to those of the non-bio-sourced products that are currently used. Better quality foams are obtained from polyols neutralised with potash or with soda.