Rigid foam comprising a polyester polyol

Abstract

A rigid foam or a composition allowing a rigid foam to be obtained, including a polyester polyol or a polymer including a polyester polyol, the polyester polyol being obtained by a first polycondensation (a) of a C3 to C8 sugar alcohol Z and two identical or different C4 to C36 diacids Y and Y′ and a second polycondensation (b) of the product obtained in (a) with two identical or different C2 to C12 diols X and X′.

Claims

1. A rigid foam or a composition allowing a rigid foam to be obtained comprising a polyester polyol or a polymer comprising a polyester polyol, wherein said polyester polyol has 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 C8 monoalcohols.

2. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein the sugar alcohol Rz is chosen from sorbitol, erythritol, xylitol, arabitol, ribitol, dulcitol, mannitol and volemitol.

3. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, comprising at least one reaction catalyst, at least one swelling agent, a stabilizer, at least one polyisocyanate having a functionality at least equal to 2, and, optionally, at least one co-polyol.

4. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, comprising at least one C2 to C8 co-polyol.

5. The rigid foam or composition allowing a rigid foam to be obtained according to claim 4, having a polyester polyol/co-polyol(s) ratio from 70/30 to 99/1.

6. The rigid foam or composition allowing a rigid foam to be obtained according to claim 4, wherein the at least one copolyol is chosen from ethylene glycol, glycerol, 1,4-butanediol, butane-1,3-diol, 1,3-propanediol, propane-1,2-diol, 1,5-pentanediol, 1,6-hexanediol, 1,2-propylene glycol, 3-oxapentane-1,5-diol, 2-[2-(2-hydroxyethoxy)ethoxy]ethanol, benzene-1,2,4-triol, benzene 1,2,3-triol, benzene 1,3,5-triol, sorbitol, erythritol, xylitol, araditol, ribitol, dulcitol, mannitol and volemitol.

7. A panel or a block of rigid foam comprising the rigid foam according to claim 1.

8. A method for thermal, sound, or cryogenic insulation or a method for filling, water-proofing, sealing or improving the buoyancy of a vessel or of an object by the deposition or the introduction of blocks or of panels of rigid foam comprising the rigid foam according to claim 1 or by spraying said rigid foam or of a composition allowing said rigid foam to be obtained.

9. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein Rz is a C5 or C6 sugar alcohol.

10. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein n is between 3 and 10.

11. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein n is between 4 and 10.

12. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein Rx and Rx′ are C3 to C8 monoalcohols.

13. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, wherein Rx and Rx′ are C4 monoalcohols.

14. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, comprising: at least 1 to 100 parts of the polyester polyol, 0 to 70 parts of at least one copolyol, 150 to 500 parts of a polyisocyanate, 0.5 to 5 parts of a catalyst, 0.5 to 15 parts of a swelling agent, 0 to 5 parts of a stabiliser, and 0 to 20 parts of a flame retardant.

15. The rigid foam or composition allowing a rigid foam to be obtained according to claim 14, wherein the catalyst is an amine catalyst.

16. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, comprising: at least 1 to 100 parts of the polyester polyol, from 1 to 50 parts of at least one copolyol, 150 to 500 parts of a polyisocyanate, 0.5 to 5 parts of a catalyst, 0.5 to 12 parts of a swelling agent, 0 to 5 parts of a stabiliser, and 0 to 20 parts of a flame retardant.

17. The rigid foam or composition allowing a rigid foam to be obtained according to claim 1, further comprising 0.5 to 12 parts of a chemical swelling agent and 0 to 60 parts of a physical swelling agent.

18. The rigid foam or composition allowing a rigid foam to be obtained according to claim 4, having a polyester polyol/co-polyol(s) ratio from 75/25 to 95/5.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1a: Petroleum-sourced PUIR Foaming Profile: temperature,

(2) FIG. 1b: Petroleum-sourced PUIR Foaming Profile: expansion speed,

(3) FIG. 1c: Petroleum-sourced PUIR Foaming Profile: maximum standardized height of the foam.

(4) FIG. 2: Evolution of the temperature of the reaction medium during the foaming of the reference and of the two biosourced foams B1-K0 and B2-PC,

(5) FIG. 3: Appearance of PUIR foams: a) 100/0, b) B1-K0, c) B2-PC,

(6) FIG. 4a: SEM images of the PUIR 100/0 foam: in the direction transverse to the expansion of the foam,

(7) FIG. 4b: SEM images of the PUIR 100/0 foam: in the longitudinal direction at the expansion of the foam, and

(8) FIG. 5: FTIR spectrum of PUIR 100/0, 35/65, B1-K0 and B2-PC foams.

EXAMPLES

(9) 1. Material and Method

(10) a. Reagents

(11) The petroleum-based polyester polyol is an aromatic polyester based on modified phthalic anhydride of STEPANP (STEPANPOL® PS-2412), called petroleum-based polyol. The biosourced polyester polyol (BASAB) was obtained from sorbitol according to an esterification process described in our patent application FR 16/01253. The properties of the petroleum-based and biosourced polyols are summarized in Table 1. D-sorbitol marketed by TEREOS SYRAL (sorbitol greater than 98%, water less than 0.5%, reducing sugars below 0.1%), 1,4 butanediol (99%) is marketed by SIGMA ALDRICH, adipic acid (99%) marketed by ACROS ORGANICS. The polyisocyanate is polymeric 4,4′-methylenebis (phenyl isocyanurate) (MDI) and N,N-dimethylcyclohexylamine (DMCHA catalyst) is from BORSODCHEM (Ongronat 2500). Various crude catalysts such as 1,3,5-tris (3-[dimethylamino] propyl)-hexahydro-triazine provided by EVONIK (Tegoamin C41), bis (2-dimethylaminoethyl) ether from BASF (Lupragen N205), 15% in weight. Potassium octoate (Ko) solution and 40% by weight. Potassium carboxylate in ethylene glycol (Pc) from EVONIK was used. The flame retardant used is SHEKOY tris (1-chloro-2-propyl) phosphate (TCPP), the surfactant is polydimethylsiloxane (B84501) from EVONIK and ethylene glycol (EG) was obtained from ALFA AESAR (purity 99%). INVENTEC isopentane was used as a swelling agent. All of these chemicals were used as received without further purification.

(12) TABLE-US-00001 TABLE 1 Principal properties of the petroleum based polyether polyol and BASAB. Hydroxyl Acidity Surface index (mg index (mg Viscosity at Primary Secondary Tension KOH/g) KOH/g) 25° C. (mPa .Math. s) Hydroxyls Hydroxyls (mN/m) petroleum- 230-250 1.9-2.5 4000 2 0 33.6 ± 0.9 based polyether polyol BASAB 490-510 less than 3 14000 2 4   40 ± 0.8

(13) b. General Method of Obtaining BASAB

(14) The reaction is carried out in a sealed stainless steel reactor equipped with a U-shaped stirring flask, a Dean Stark having an outlet at the top of the condenser to be able to link a vacuum pump and a low output to recover the condensates, an inlet and an outlet of inert gas. In the reactor, sorbitol and adipic acid are introduced in powder form in a 1/2 molar ratio (sorbitol/adipic acid). The reactor is placed in an inert atmosphere and then heated. When the temperature reaches 100° C., stirring is progressively increased to 170 rpm. When the temperature reaches 150° C., the reaction is started and continued for 3 hours. After 3 hours, 1,4 butanediol (called diol hereinafter) is introduced into the reactor in a molar ratio (1,4 butanediol/sorbitol) 2.2/1. The temperature of the reaction medium returns to 150° C. (stirring still maintained at 170 rpm, inert atmosphere). 2 h30 after the return to 150° C. a passage under partial vacuum is carried out under partial vacuum for a period of one minute then atmospheric pressure is brought back under an inert atmosphere. 4 h30 after the addition of diols, a new flush of partial vacuum is carried out for 2 minutes then the atmospheric pressure is brought under an inert atmosphere. 6 h15 minutes after the introduction of the dioi (ie a total reaction time of 9 h 15 min at 150° C.), the reactor is stopped and the reaction product is recovered hot so as to have a minimum loss during the transfer of material from the reactor to the conditioning of the product.

(15) c. General Method of Preparing Foams PUIR

(16) The isocyanate/hydroxyl molar ratio (NCO/OH) was maintained at 3.2 in all PUIR formulations, to determine the amount of isocyanate, all the reactive hydroxyl groups are taken into account, namely polyols, water and solvents coming from the batch of the chosen catalysts. On the basis of the two-component foaming process, a first mixture was prepared containing polyols, catalysts, surfactants (poiydimethylsiloxane, B84501), flame retardants (TCPP), swelling agent (isopentane) and water. In each preparation, the number of parts (p) of the water, the TCPP, the surfactants are constant at 0.9p, 15p, 2.5p, respectively, and the total amount of polyol never exceeds 100p. The amount of swelling agent was kept constant at 24% to obtain foams of comparable densities. The mixture was mechanically stirred until a fine white emulsion was obtained with complete incorporation of the swelling agent. The mixture and the temperature of the polyisocyanates were checked and adjusted to 20° C. Then, the appropriate amount of polyisocyanate allowing an NCO/OH ratio of 3.2 was quickly added with a syringe to the emulsion. The entire reaction mixture was stirred vigorously for 5 seconds, and the foam was allowed to expand freely in a 250 mL disposable beaker at room temperature (controlled at 20° C.) or in a FOAMAT device. The characteristic constants of foaming kinetics were noted, namely cream time, string time and tack-free time. Prior to analysis, the foam samples were stored at room temperature for three days to achieve complete dimensional stability (no shrinkage).

(17) A formulation containing only a petroleum-based polyester polyol was considered as a reference formulation (Table 1). This formulation is transposed to formulations containing 65% and 100% (equivalent to 65p and 100p, respectively) of BASAB indicated as 35/65 and 0/100 (PS2412/BASAB), respectively. The formulation was then optimized in formulations containing 85% (equivalent to 85 parts) of BASAB. Formulations containing BASAB are shown in Table 3.

(18) TABLE-US-00002 TABLE 2 PUIR foam formulation indicated in parts N° Parts Polyols Petroleum-based 100 Catalyst C41 0.3 N205 0.12 Ko 3 other Water 1 Surfactant 2.5 Flame retardant 15

(19) d. Characterizations

(20) Thermogravimetric (TGA) analyzes were performed using a TA Hi-Res TGA Q5000 instrument in reconstituted air (flow rate 25 mL/min). 1-3 mg samples were heated from room temperature to 700° C. (10° C./min). The main characteristic degradation temperatures are those at maximum of the weight loss derived curve (DTG) (T.sub.deg, max) and characteristic temperatures corresponding to 50% (T.sub.deg50%) and 100% (T.sub.deg100%) weight loss have been reported. Infrared spectroscopy was performed with a Fourier Nicolet 380 transformed infrared spectrometer used in reflection mode equipped with an ATR diamond module (FTIR-ATR). An atmospheric background was collected before each sample analysis (64 scans, resolution 4 cm.sup.−1). All spectra were normalized on a C—H stretch peak at 2950 cm.sup.−1.

(21) Foam temperature, height and expansion rates, density and pressure were recorded using a FOAMAT FPM 150 (Messtechnik GmbH) equipped with cylindrical vessels, 180 mm high and 150 mm in diameter, an ultrasonic probe LR 2-40 PFT recording foam heights, a NiCr/Thermocouple Ni type K and a pressure sensor FPM 150. The data was recorded and analyzed with specific software.

(22) Closed cell content is determined using a Quantachrome Instruments Ultrapyc 1200e based on the technique of gas expansion (Boyle's Law). Cubic samples of foams (approximately 2.5 cm×2.5 cm×2.5 cm) are cut for the first measurement, then the sample is cut once more into eight pieces and the measurement repeated. The second step is to correct the contents of the closed cells based on cells that have been damaged due to the cut of the sample. Measurements were made according to EN ISO4590 and ASTM 6226.

(23) Foam cell morphology was observed with Jeol JSM-IT100 electronic emission scanning electron microscope (SEM). The cubic foam samples were cut with a microtome blade and analyzed in two characteristic orientations: longitudinal and transverse to the direction of the foam surges. Using the ImageJ (Open Source Processing Program) software, the average size of the cell was measured as the aspect ratio of the cell defined by equation 1.

(24) $R=\frac{1}{n}\underset{i=1}{\overset{n}{.Math.}}\frac{D_F^{\max }}{D_F^{\min }}$

(25) Where D.sub.Fmax and D.sub.Fmin have maximum and minimum Feret diameters, n is the number of cells measured for a given sample.

(26) II. Results and Discussion

(27) a. Kinetics of PUIR Reference Foam

(28) The petroleum-based (100/0) PUIR foam exhibits rapid foaming with characteristic times shown in Table 3. In order to evaluate the foaming kinetics of these different formulations, the characteristic times of cream, string time and tack-free time were measured.

(29) The cream time represents the initiation of the polyaddition reaction between the isocyanate functions provided by the polyisocyanates and the water or alcohol groups provided by all the polyols, co-polyols or additives present in the formulation. The cream time is characterized by a color change of the reaction medium before the expansion of the foam.

(30) The String time represents the beginning of the formation of the polyurethane and/or polyisocyanurate polymer network. It is characterized by the formation of sticky string when physical contact is made with the expanding foam.

(31) The tack-free time represents the end of the polymerization of the polyurethane and/or polyisocyanurate network at the surface of the foam. It is characterized by a foam that is no longer sticky to the touch.

(32) The characteristic times recorded for 100/0 are 10 s, 60 s and 148 s for the cream time, lead time and tack time, respectively. The macroscopic appearance of such a PUIR foam is characteristic (FIG. 3a) and has a typical neck induced by the second growth of the foam during the trimerization of isocyanates. This second growth is really visible on the Foamat measurements presented in FIG. 1, b. The expansion rate of the foam begins to decrease after 30 s of reaction and increases again after 60 s of reaction. The foam temperature curve (FIG. 1a) also shows a point of inflection at 50 s and increases up to 150° C., which corresponds to the trimerization of the isocyanates. The same phenomenon is visible in FIG. 1c, representing the maximum height of the foam. After 50 s, a variation of the slope is observed and the maximum height increases rapidly from 80 to 100% with the trimerization of the isocyanates.

(33) b. Kinetics of PUIR Foams Containing BASAB

(34) Two formulations similar to reference (100/0) containing only PS 2412 were made with the following polyester polyol ratios: 35/65 and 0/100 (parts/parts) of PS 2412/BASAB (Table 3). Analysis of the cream time of the formulations 35/65 and 0/100 shows that the beginning of the polyaddition reaction between the polyols and the polyisocyanates is shifted from the reference by 9 and 14 s, respectively. The string time of the 0/100 foam is not measurable because it is certainly confused with the tack-free time superiot to 300 s while the reference has a tack-free time 148 s. The comparison of these two tack-free times clearly shows that the catalyst mix traditionally used for the formulation containing 100% petroleum-based polyol is not as suitable for the formulation containing 100% of the biosourced polyol of the invention. That is, the exothermicity of the polyaddition reaction is different and results in lower activity of the catalysts.

(35) The activation of these catalysts is at the origin of the rapidity of formation of the polyurethane network, and at the origin of the reaction for the formation of the triisocyanuric rings.

(36) Surprisingly, the 35/65 formulation has a 48 seconds shorter tack-free time than the reference. This means that the 35 parts of PS 2412 are enough to maintain the activation of the traditional catalyst game. Also, the superior and unconventional functionality of the BASAB for a PUIR formulation makes it possible to reach the characteristic tack-free time the foam more quickly.

(37) Two identical formulations to the control were prepared by replacing the PS 2412 reference polyol with BASAB. Foams could be obtained with good characteristics for the 35/65 foam. Nevertheless, during a total replacement, the 0/100 foams obtained have characteristic relatively slow measured foaming times.

(38) Indeed, better results are obtained by using a combination of a co-polyol with BASAB. Ethylene glycol (EG) was preferred because being a short diol, it was very reactive, to promote initiation of the first exothermic reaction and increase the reaction between BASAB and polyisocyanate molecules. After different BASAB/EG ratio tests, the 85/15 wt % ratio showed the best result in the PUIR foam formulation.

(39) Two catalysts were compared: potassium octoate (Ko) and potassium carboxylate (Pc). This last smaller catalyst, has a greater mobility and therefore a greater activity in the medium. The resulting optimized formulations, namely a B1-K0 formulation comprising 100% of biosourced polyester polyol (85 parts of BASAB and 15 parts of ethylene glycol) and potassium octoate (Ko) and a B2-PC formulation comprising 100% of biosourced polyester polyol (85 parts of BASAB and 15 parts of ethylene glycol and potassium carboxylate (Pc) are detailed in Table 3. The reference formulation (100/0) comprises 100% petrosourced polyester polyol (PS 2412) and potassium octoate (Ko).

(40) TABLE-US-00003 TABLE 3 Catalyst ratio and Characteristic Times of the Different PUIR Foams Reference (100/0) 35/65 0/100 B1-K0 B2-PC Formulation PS 2412 100.sup.a  35   .sup. 0  0.sup.a  0.sup.a BASAB  0.sup.a  65  .sup. 100  85.sup.a  85 EG  0.sup.a  0   .sup. 0  15.sup.a  15.sup.a Ko  0.12.sup.b  0.12.sup.b   .sup. 0.12.sup.b  0.17.sup.b  0.sup.b N205  0.03.sup.b  0.03.sup.b   .sup. 0.03.sup.b  0.08.sup.b  0.22.sup.b Tegoamine C41  0.08.sup.b  0.08.sup.b   .sup. 0.08.sup.b  0.21.sup.b  0.11.sup.b Pc  0.sup.b  0.sup.b   .sup. 0.sup.b  0.sup.b  0.97.sup.b Caracteristic Cream time (s)  10  19  .sup. 24  12  11 times String time (s)  60  76 n.m 134  82 Tack-free time (s) 148 100 ≥300 166 120 .sup.aexpressed as a number of parts with respect to the final product, .sup.bexpressed as a percentage relative to the final product, n.m: not measurable.

(41) The B1-K0 formulation catalyzed with the same catalyst as the reference but in greater amount has a cream time relatively similar to the latter (Table 3). However, B1-K0 has a string time that has a delay of 74 seconds compared to the reference time and a delay of 18 seconds for the tack-free time. It is evidenced from these results that the formulation B1-K0 has distinct characteristics in terms of characteristic times compared to the reference. These differences, in particular the lengthening of the characteristic times, are an advantage to the formulation of rigid rigid PUIR foam produced in molds.

(42) On the other hand, compared to the reference, the biosourced B2-PC formulation has a catalyst different from that of the reference. It is observed that the cream time of this formulation as well as the string times are closer to the times of the reference formulation, whereas the B2-PC tack-free time is 28 seconds faster than that of the reference. It is evidenced from these results that the B2-PC formulation has distinct characteristics in terms of characteristic time compared to B1-K0. This formulation having shorter characteristic times and similar to those of the reference is an advantage for the in-line production processes of rigid PUIR foam insulation board.

(43) Beyond the characteristic times, the most important difference between these formulations is macroscopic.

(44) Indeed, the characteristics of the foams of the previous formulations have been compared. It appears that the B2-PC foam has a clean surface, with a smooth outer skin, similar to the reference, while B1-K0 has an irregular surface (FIGS. 3, b and c) (presence of cracks and bubbles).

(45) The main hypothesis justifying these surface differences between the B1-K0 foam on the one hand and the B2-PC and reference foams on the other hand is based on the differences in string time. Indeed, the string time of 134 s of B1-K0 is longer than that of B2-PC which is 82 s.

(46) Since the B1-K0 and B2-PC formulations contain the same polymer, the longer string time reflects a longer time to reach the same degree of polymerization and therefore instability or fragility of the material during this step of polymerization. This fragility causes the cell walls to collapse under the pressure of the expanding gas generating visible cracks and bubbles on the surface of the foam. This takes place before the curing of the foam and the end of the polymerization, ie before the end of the foaming process.

(47) The evolution of the internal temperature of the foams during the foaming process was evaluated (FIG. 2). It is clear that the B1-PC foam rises more quickly than the B1-K0 foam. This reflects a greater reactivity of the reaction medium, certainly due to the choice of catalysts. In addition, the B1-K0 sample has a lower foaming temperature in all respects to the other two foams presented. The foaming temperature curve of B1-PC has a profile similar to that of the reference until the characteristic inflection thereof corresponding to the trimerization of isocyanates.

(48) Finally, it can be seen that the overall kinetics of the PUIR foam of B2-PC is very close to the reference foam and the temperature of the foam is 140° C., which is similar to the foaming temperature of the petroleum-sourced reference.

(49) The best foaming reactivity and therefore the best foaming kinetics, was obtained by increasing the foaming temperature (in particular by the catalyst change), by increasing the amount of BASAB in the mixture and by the addition of a co-polyol.

(50) Thus, these results demonstrate that a PUIR foam formulation comprising biosourced polyol polyesters and having characteristics comparable to those of a petroleum-based polyester polyol formulation can be obtained. Such a formulation is particularly advantageous for rapid continuous in-line production of foam blocks or panels. On the other hand, these results also reveal that other types of PUIR formulations comprising biosourced polyol polyesters having foaming characteristics slower than the reference based on polyesters polyesters petroleum-based can also be obtained. Such formulations represent an advantage for the production of molded block foam. The bio-based polyester polyol (BASAB) is particularly advantageous in that it offers the opportunity to adapt the foaming characteristics or the kinetics of the foam according to the desired applications or manufacturing processes.

(51) c. Closed Cell Percentage and Foam Morphology

(52) The morphologies of the foams obtained were compared by SEM. FIG. 4 shows the SEM images of samples of the reference PUIR foam cut in the transverse and longitudinal direction at the rise of the foam after foaming A typical alveolar structure in the transverse direction is clearly observed. Stretching of the cell in the longitudinal direction is characteristic of a partially free foaming process performed in an open cylindrical container (M. C. Hawkins, J. Cell. Plast., 2005, 41, 267-285). The SEM observations allowed the measurement of the anisotropic coefficients R of PUIR foams: 100/0, 35/65, 0/100, B1-K0 B2-PC studied (Table 4).

(53) The anisotropic coefficients (R) reflect the shape of the cells of a foam. The coefficient R is the ratio of the two maximum measurable diameters in a cell. Thus a perfectly round cell will have a coefficient R equal to 1 (all diameters are identical in a circle). In contrast, a stretched cell of oval shape will have a coefficient R greater than 1. In this study the coefficients R are determined in two different planes. This makes it possible to evaluate the shape of the cells in a transversal section to the direction of expansion of the PUIR foams and similarly in the longitudinal direction to the expansion of the PUIR foams.

(54) It is observed that for the R coefficients of the formulations 100/0, B1-K0 and B2-PC are close to 1.8 in the longitudinal direction. This means an oval shape of the cells of the foam. In the direction transverse to the rising of the foam, the calculated coefficient R is closer to 1.2. It reflects here a form of cells closer to the spherical shape. The formulations 35/65 and 0/100 have coefficients R less comparable. The wide distribution of cell sizes of these foams which results in large standard deviations of all their Feret diameters in the longitudinal and transverse directions results in cells of very anisotropic shape.

(55) Comparing the reference foam with 34/65 and 0/100 foams, the latter have cells approximately 2 to 4 times larger than the reference based on 100% petrol-based polyol in all directions of study. The size of the cells is an impacting criterion for the final properties of a PUIR foam. For example, large cells generate poorer thermal insulation properties.

(56) Comparing the reference foam with PUIR B1-K0 and B2-PC biosourced foams, the latter have cells of sizes almost similar to those of the reference in all directions (Table 4). Compared to the 35/65 and 0/100 formulations, their cell sizes are significantly smaller. This major gain on biosourced formulations is an advantage for their use in the field of thermal insulation of the building for example.

(57) TABLE-US-00004 TABLE 4 Feret's diameter and anisotropy coefficient (R) of all foams PUIR in the longitudinal and transverse directions in the direction of foaming 100/0 35-65 0/100 B1-K0 B2-PC Longitudinal Feret max,  408 ± 117 643 ± 189 860 ± 170 524 ± 215 521 ± 123 direction D.sub.F.sup.max (μm) Feret min, 223 ± 44 518 ± 147 550 ± 130 295 ± 112 298 ± 67  D.sub.F.sup.min (μm) D.sub.F.sup.max/D.sub.F.sup.min 1.83 1.25 1.56 1.78 1.75 Traversal Feret max, 275 ± 72 940 ± 260 1240 ± 380  386 ± 123 448 ± 122 direction D.sub.F.sup.max (μm) Feret min, 242 ± 72 420 ± 90  990 ± 300 324 ± 116 347 ± 122 D.sub.F.sup.min (μm) D.sub.F.sup.max /D.sub.F.sup.min 1.14 2.24 1.25 1.19 1.29

(58) The study of the previous kinetic foaming profiles has shown that the temperatures reached by the reaction medium during the foaming process are lower for the B1-K0 and B2-PC foams. These low temperatures are responsible for a delay before the trimerization of the isocyanates, causing lower reaction rates (longer string time). The increase in string time induces an increase in the coalescence process of the gas bubbles before complete polymerization of the polyurethane and polyisocyanurate network of the foam, which explains the observation of larger cell sizes for biosourced foams.

(59) d. Foam Properties: Density, Closed Cell Rates and Chemical Composition (FT-IR)

(60) TABLE-US-00005 TABLE 5 PUIR foam properties. 100/0 35-65 0/100 B1-K0 B2-PC Bulk Density 31.1 39.8 n.d 33.8 ± 2 32.8 ± 0.8 (kg/m.sup.3) Closed-cells 95 <50 <50 86 85 percentage (%) n.d: not determined

(61) The apparent density of the foams shown in Table 5 is similar for all PUIR formulations, and is between 31 and 40 kg/m.sup.3. The 35/65 foam has the highest apparent density (39.8 kg/m.sup.3) and it is also the foam that has the lowest foaming temperature. The low foaming temperature limited the expansion of the swelling agent, resulting in a slightly more dense foam than the others. Foams B1-K0 and B2-PC, the optimized formulation does not have this characteristic since their density is closer to that of the reference.

(62) In order to confirm the chemical nature of the foams obtained, an infrared spectrometric (FT-IR) analysis was carried out. The FT-IR spectra of the formulated foams are shown in FIG. 5. All foams show characteristic peaks such as stretching stretching of NH groups at 3400-3200 cm.sup.−1 and stretching vibrations of the C═O bond present in urethane groups at 1705 cm.sup.−1. Signals at 2955 cm.sup.−1 and 2276 cm.sup.−1 are respectively attributed to C—H bond stretching of the polyurethane backbone and unreacted residual NCO groups. The 1596 cm.sup.−1 signal corresponds to Ar—H stretching in phenyl groups derived from the polymeric polyisocyanate. The bending signal of the N—H groups is located at 1509 cm.sup.−1 and the C—O stretch at 1220 cm.sup.−1. Then, a strong signal at 1408 cm.sup.−1 is attributed to the presence of isocyanurate rings typical of the PUIR foam formulation.

(63) It is therefore concluded that the foams obtained, and in particular the foams based on biosourced polyester polyol, have a similar chemical composition to that of the 100% petroleum-based polyester polyol based foam. This proves that the differences concerning the characteristic times or foaming temperatures previously observed did not prevent the good formation of a PUIR network in all the formulations.

(64) e. Thermal Resistance of Foams

(65) The thermal stability of the PUIR foam samples was investigated by thermogravimetric analysis of the ATG and DTGA curves of all PUIR foams (not shown). All PUIR foams have classic weight loss in two stages. PUIR B1-K0 and B2-PC foams have superior thermal stability compared to the reference. Table 6 shows the maximum temperatures of the curve derived from weight loss: T.sub.degmax1 and T.sub.degmax2. T.sub.degmax1 is around 300° C. for the three foams. T.sub.degmax2 is observed at a temperature of 523° C. for the reference while the B1-K0 and B1-PC foam has higher T.sub.degmax2, respectively 538 and 534° C.

(66) In addition, they have a shoulder of the DTGA curve at more than 600° C. The first T.sub.degmax1 corresponds to the decomposition of the urethane bond. The mechanism of decomposition of the urethane linkage is generally described as simultaneous dissociation of isocyanate and alcohol, formation of a primary and secondary amine, and formation of olefins. The second T.sub.degmax2 is more pronounced than the first T.sub.degmax1 and is associated with double degradation of isocyanurate and cleavage of carbon-carbon bonds (J. E. Sheridan and C. A. Haines, J. Cell. Plast., 1971, 7, 135-139). The first weight loss is less important because there is an isocyanurate bond. Isocyanurates are thermally more stable than urethane due to the absence of labile hydrogen and thus the second weight loss is mainly caused by carbon-carbon cleavage (H. E. Reymore et al., J. Cell. Plast., 1975, 11, 328-344). In the specific case of B1-K0 and B2-PC, T.sub.degmax2 is higher and is attributed to their higher concentration in BASAB compared to the reference. The higher OH value of BASAB compared to PS 2412 increases the formation of urethane linkages and cross-linking of the PUIR network (A. A. Septevani, et al Ind. Crops Prod., 2015, 66, 16-26; Javni, Z. S., et al., J. Appl. Polym. Sci., 2000, 77, 1723-1734) making it more resistant to thermal degradation.

(67) Table 6 also shows two temperatures corresponding to 50% (T.sub.deg50%) and 100% (T.sub.deg100%) weight loss of PUIR foams, respectively. T.sub.deg50% and T.sub.deg100%. The latter are similar between the reference foams and B1-K0. The B2-PC sample has a T.sub.deg50% and a T.sub.deg100% higher than those of the reference foam, which is in agreement with the previous observations. As a result, the B2-PC formulation makes it possible to obtain a foam that is more resistant to temperature than the reference foam based on petroleum-based polyester polyol.

(68) TABLE-US-00006 TABLE 6 Degradation at 95% and 50% weight loss of PUIR foams samples ATG DTG Sample T.sub.deg50% (° C.) T.sub.deg100% (° C.) T.sub.deg50% (° C.) T.sub.deg100% (° C.) 0% 448 645 301 523 (Reference) B1-K0-PC 458 632 300 538 B2-PC 499 690 295 534

(69) Closed cell PUIR foams based on the total substitution of a petroleum-sourced polyester polyol by the biosourced polyester polyol have been successfully prepared. The optimization of the formulation allowed to obtain a kinetics of foaming similar to that of the reference petroleum-sourced. The study was conducted using two different catalysts. PUIR foams have a high content of closed cells which is very interesting for meeting thermal insulation characteristics. Finally, the most striking point concerns PUIR biosourced foams which has a higher stability to thermal degradation than the petroleum-sourced reference.