Hybrid Polyurethane-Polyhydroxyurethane Composition

Abstract

The present invention relates to a hybrid polyurethane-polyhydroxyurethane (PU-PHU) composition obtained by a process comprising the following steps: (i) Reacting at least one isocyanate containing compound, in stoichiometric excess, with at least one isocyanate-reactive compound, resulting in the formation of at least one prepolymer, (ii) Reacting said at least one prepolymer with at least one cyclic carbonate functional group containing compound, leading to the formation of a cyclic carbonate-terminated prepolymer, (iii) Ring-opening reaction of said cyclic carbonate-terminated prepolymer with at least one amine functional group containing compound resulting in said hybrid PU-PHU composition,
characterised in that said ring-opening reaction step is carried out above room temperature, preferably above 20° C., more preferably above 25° C.

Claims

1. A method of making a hybrid polyurethane-polyhydroxyurethane (PU-PHU) composition obtained by a process comprising the following steps: (i) reacting at least one isocyanate containing compound, in stoichiometric excess, with at least one isocyanate-reactive compound, resulting in the formation of at least one prepolymer, (ii) reacting said at least one prepolymer with at least one cyclic carbonate functional group containing compound, leading to the formation of a cyclic carbonate-terminated prepolymer, (iii) ring-opening reaction of said cyclic carbonate-terminated prepolymer with at least one amine functional group containing compound resulting in said hybrid PU-PHU composition, characterised in that said ring-opening reaction step is carried out above room temperature.

2. The method according to claim 1, wherein said at least one cyclic carbonate functional group containing compound comprises at least one 4-membered cyclic carbonate.

3. The method according to claim 1, wherein the amine of said at least one amine functional group containing compound has a functionality of at least 1.8.

4. The method according to claim 1, wherein the temperature at which said ring-opening reaction step is carried out ranges from 25° C. to 160° C.

5. The method according to claim 1, wherein said at least one isocyanate-reactive compound has a number average molecular weight equal to or higher than 62.

6. The method according to claim 1, wherein step (ii) is carried out at a molar ratio of said at least one prepolymer to said at least one cyclic carbonate functional group containing compound (NCO:OH) ranging from 0.5 to 1.05.

7. The method according to claim 1, wherein said at least one prepolymer has an NCO value ranging from 0.8 to 25%.

8. The method according to claim 1, wherein step (ii) is performed at a temperature ranging from 50° C.

9. The method according to claim 1, wherein step (ii) is carried out in a solvent free condition.

10. The method according to claim 1, wherein step (ii) and/or step (iii) is carried out in presence of a catalyst selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), triazabicyclodecene (TBD), triethylamine, and potassium t-butanoate, and mixtures thereof.

11. The method according to claim 1, wherein said at least one cyclic carbonate functional group containing compound is glycerol carbonate.

12. The method according to claim 1, wherein step (iii) is achieved in a period of time of up to 3 hours.

13. The method according to claim 1, wherein the conversion of the cyclic carbonate-terminated prepolymer of step (iii) is of at least 90%.

14. A product comprising a PU-PHU composition made according to claim 1.

15. A method for processing a thermoset hybrid PU-PHU product, wherein the method comprises the following steps: providing a cured thermoset hybrid PU-PHU product made by the process according to claim 1, which product has an outer surface; processing said cured thermoset hybrid PU-PHU product by applying at least one stimulus, onto said outer surface, at a predetermined temperature and/or for a predetermined period of time; and obtaining a processed hybrid PU-PHU product.

Description

EXAMPLES

Example 1—Synthesis of NCO Terminated Prepolymers

[0117] The NCO terminated prepolymers were prepared by reacting an isocyanate and a polyol in a molar ratio NCO/OH 2:1 (or higher).

[0118] 400.24 g of 4,4′-MDI (SUPRASEC®1306; 3.19 mol —NCO, NCOv=33.52%) are weighed out in a reactor with 4-neck lid equipped with mechanical stirrer, addition funnel, digital thermocouple and nitrogen flow. The 4,4′-MDI is heated to 80° C., under nitrogen flux. When the reaction temperature is reached, 1593.72 g of PPG (functionality=1.98, OHv=56.2 mg KOH) (1.60 moles —OH) are added drop wise, while the mixture is mechanically stirred under nitrogen blanket. The conversion of isocyanates is monitored via potentiometric NCO titrations, until the targeted NCOv (3.37±0.05%) is reached and maintained a constant value over time. The obtained NCO terminated prepolymers having a non-Newtonian viscosity of 30 Pa.Math.s at ambient temperature (25° C.) can be stored in a sealed metal bottle under nitrogen atmosphere.

Example 2—Functionalisation of Prepolymers with Glycerol Carbonate (GC)

[0119] In this example, the functionalisation is performed with the same setup used for the synthesis of the prepolymer obtained in example 1. GC (JEFFSOL®) and isocyanates are reacted in an equimolar ratio. The reaction is performed in a catalyst free condition. 250.11 g of the prepolymer (0.2 mol —NCO) of example 1 is heated at 70° C., under nitrogen blanket. When the prepolymer reaches the reaction temperature, 23.67 g of GC (0.2 mol —OH) is added drop wise with an addition funnel. The reaction is highly exothermic, and the mixture turns from transparent to opaque white. The reaction was followed by ATR FT-IR, and monitored by observing the disappearance of the peak at 2270 cm.sup.−1, corresponding to unreacted isocyanates, and, at the same time, observing the rise of the urethane peak at 1726 cm.sup.−1. When the reaction is completed, the product was stored at room temperature, under nitrogen atmosphere.

[0120] GC terminated prepolymer has a non-Newtonian viscosity of 1333 Pa.Math.s at ambient temperature (25° C.).

[0121] Preferably, the DABCO catalyst could be occasionally used up to 0.05 wt. %, in order to reduce the reaction time.

Example 3—Synthesis of NCO Terminated Prepolymers

[0122] The NCO terminated prepolymers were prepared by reacting an isocyanate and a polyol with a MW of 4000 in a molar ratio NCO/OH 2:1 (or higher).

[0123] 200.09 g of 4,4′-MDI (SUPRASEC®1306; 1.6 mol —NCO, NCOv=33.48%) are weighed out in a reactor with 4-neck lid equipped with mechanical stirrer, addition funnel, digital thermocouple and nitrogen flow. The 4,4′-MDI is heated to 80° C., under nitrogen flux. When the reaction temperature is reached, 1597.94 g of PPG (functionality=1.98, OHv=28.2 mg KOH) (0.8 mol —OH) are added drop wise, while the mixture is mechanically stirred under nitrogen blanket. The conversion of isocyanates is monitored via potentiometric NCO titrations, until the targeted NCOv (1.85±0.05%) is reached and maintained a constant value over time. The obtained NCO terminated prepolymers having a non-Newtonian viscosity of 25 Pa.Math.s at ambient temperature (25° C.) can be stored in a sealed metal bottle under nitrogen atmosphere.

Example 4—Functionalisation of Prepolymers with Glycerol Carbonate (GC)

[0124] In this example, the functionalisation is performed with the same setup used for the synthesis of the prepolymer obtained in example 3. GC and isocyanates are reacted in an equimolar ratio. The reaction is performed in a catalyst free condition. 750 g of the prepolymer (0.33 mol —NCO) of example 3 is heated at 70° C., under nitrogen blanket. When the prepolymer reaches the reaction temperature, 40.93 g of GC (0.35 mol —OH) is added drop wise with an addition funnel. The reaction is highly exothermic and the mixture turns from transparent to opaque white. The reaction was followed by ATR FT-IR, and monitored by observing the disappearance of the peak at 2270 cm.sup.−1, corresponding to unreacted isocyanates, and, at the same time, observing the rise of the urethane peak at 1726 cm.sup.−1. When the reaction is completed, the product was stored at room temperature, under nitrogen atmosphere.

[0125] GC terminated prepolymer has a non-Newtonian viscosity of 852 Pa.Math.s at ambient temperature (25° C.).

[0126] Preferably, the DABCO catalyst could be occasionally used up to 0.05 wt. %, in order to reduce the reaction time.

Example 5—Viscosity Measures

[0127]

TABLE-US-00002 TABLE 1 Viscosity Viscosity Viscosity at 25° C. at 50° C. at 75° C. (Pa .Math. s) (Pa .Math. s) (Pa .Math. s) Prepolymers SUPRASEC ® 1306/PPG2000 30 4.9 1.3 (NCOv = 3.36%) - example 1 SUPRASEC ® 1306/PPG4000 25 3.8 1.1 (NCOv = 1.86%) - example 3 GC terminated prepolymers GC- 1333 100 15 SUPRASEC ®1306/PPG2000 - example 2 GC- 852 71 9 SUPRASEC ®1306/PPG4000 - example 4

Example 6—Polymerisation of GC Terminated Prepolymer of Example 2

[0128] The synthesised GC-functionalised prepolymer of example 2 is reacted with JEFFAMINE® EDR 148, bifunctional primary amine, in a stoichiometric ratio carbonate ring/—NH.sub.2 1:1, in presence of 0.5 wt. % of DABCO. The reaction is performed with dry nitrogen and a mechanical stirrer, and the internal temperature of the reaction is monitored with a digital thermocouple.

[0129] 74.81 g of the GC-terminated prepolymer (0.027 mol) is weighed out in a disposable glass bottle, DABCO is added (0.5 wt. %) and the mixture is heated with an oil bath at 100° C., under vigorous mechanical stirring. When the reaction temperature is reached, 4.053 g of JEFFAMINE® EDR 148 (0.0274 mol) is added with an addition funnel.

[0130] The reaction is monitored with ATR FT-IR by observing the disappearance of the carbonyl peak at 1810 cm.sup.−1, and the simultaneous appearance of the urethane carbonyl peaks at 1704 cm.sup.−1. The reaction is then stopped after 2 hours, when no further changes were observed in the infrared spectra. The final product is opaque and white.

[0131] Preferably, when two different amines are used, the less reactive is added first, and reacts for 15 minutes, and eventually, the second amine is added. The stirring time is thereby adapted depending on the reactivity of the amine(s) employed and, consequently, on the resulting viscosity build-up.

[0132] The carbonate ring-opening conversion is 91%, measured with FT-IR.

Example 7—Polymerisation of GC Terminated Prepolymer of Example 4

[0133] The same procedure as detailed for example 6 is applied, except that the GC terminated prepolymer of example 4 was used.

[0134] In this example, the carbonate ring-opening conversion is 94%, measured with FT-IR.

Example 8—Combination of Amines

[0135] Table 2 illustrates two embodiments of example 8. PU-PHU products are prepared by reacting GC terminated prepolymer of example 2 (NCOv of 3.37 wt %-S1306/PPG2000) with a mixture of ECA-29 and JEFFAMNE® EDR 148 in different proportions of amines (i.e., 50 wt. % and 100 wt. %, respectively samples 1 and 2). In the present example, the cures are performed by reacting 69.55 g of GC terminated prepolymer (0.0254 mol) with 1.88 g of difunctional JEFFAMNE® EDR 148 (0.0127 mol) first, and after 15 minutes 3.46 g of ECA-29 (0.0128 mol) is added to complete the curing.

[0136] It was found that when only 25 wt. % of ECA-29 was used, the material becomes soluble in warm DMSO and thermo-processable. When using at least 50 wt. % of ECA 29, the resulting polymers were thermoset, indicating a significant degree of crosslinking.

[0137] Mechanical properties are also illustrated in table 2

TABLE-US-00003 TABLE 2 JEFFAMINE ® Elongation Stress Young's EDR 148 ECA-29 at break at break Modulus PU-PHU (mol %) (mol %) (%) (kPa) (kPa) 1 50 50 2214 4104 1322 2 0 100 893 3261 1757

[0138] Mol % referred in the aforementioned table is expressed relative to the total moles of GC-prepolymer.

Example 9—Trifunctional Amine

[0139] Table 3 illustrates two embodiments of example 9. PU-PHU products are prepared by reacting GC terminated prepolymer of example 2 (NCOv of 3.37 wt %-S1306/PPG2000) and example 4 (NCOv of 1.85 wt %-S1306/PPG4000) with tris(2-aminoethyl)amine (trifunctional amine).

[0140] The same protocol as described above is applied, resulting in the conversion of GC-terminated prepolymer of 93%, after one hour.

[0141] The mechanical properties of the polyhydroxyurethanes prepared with tris(2-aminoethyl)amine are illustrated in table 3 below.

TABLE-US-00004 TABLE 3 Elongation Stress Young's at break at break Modulus PU-PHU Amine (%) (kPa) (kPa) NCOv of tris(2- 555 2895 1919 3.37 wt %- aminoethyl)amine S1306/PPG2000 NCOv of tris(2- 1056 1384 763 1.85 wt %- aminoethyl)amine S1306/PPG4000

Example 10

[0142] A dry hybrid PU/PHU thermoset polymer, prepared from a GC-prepolymer, as illustrated in example 2 (Suprasec 1306+PPG 2000 NCOv=3.37%) and tris(2-aminoethyl)amine, was cut into small pieces having approximately dimensions (l, w, t) 3×4×2 mm.

[0143] The beads were placed on a sheet of non-sticking paper forming a circle having a diameter of 6 cm. The sample was then placed on the bottom plate of an hydraulic press Servitec Polystat 200T, previously pre-heated at 140° C., and a mechanical pressure of 11 MPa was applied in order to obtain a thickness of 1 mm. After 30 minutes the sample was removed from the press and allowed to cool down at room temperature. As a result of the reprocessing procedure, the small pieces merged into a single film. At least one “dogbone” specimen for tensile test was cut out of the reprocessed film. The remaining part was cut again into small pieces and reprocessed following the same procedure up to three times in total.

TABLE-US-00005 Young Strain Stress Modulus at break at break Specimen (MPa) (%) (MPa) PU-PHU polymer 1.73 358 2.57 Reprocessed PU-PHU 1st 1.81 345 4.37 cycle Reprocessed PU-PHU 2nd 1.63 249 2.85 cycle Reprocessed PU-PHU 3rd 1.64 295 3.61 cycle

[0144] The tensile mechanical properties were determined with a Zwick ProLine Z020 testing machine. The following parameter have been employed: strain speed 200 mm/min, pre-load 0.5 N, modulus was calculated between 5% and 10% strain.

[0145] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0146] As used herein, the singular forms “a”, “an”, and “the” include both singular and plural referents unless the context clearly dictates otherwise. By way of example, “an isocyanate group” means one isocyanate group or more than one isocyanate group.

[0147] The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes” or “containing”, “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms “comprising”, “comprises” and “comprised of” as used herein comprise the terms “consisting of”, “consists” and “consists of”. This means that, preferably, the aforementioned terms, such as “comprising”, “comprises”, “comprised of”, “containing”, “contains”, “contained of”, can be replaced by “consisting”, “consisting of”, “consists”.

[0148] Throughout this application, the term “about” is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value.

[0149] As used herein, the terms “% by weight”, “%”, “weight percentage”, or “percentage by weight” are used interchangeably.

[0150] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 30 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0151] All references cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings of all references herein specifically referred to are incorporated by reference.

[0152] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0153] Throughout this application, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Although the preferred embodiments of the invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions or substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.