FR2919874A1 - METHOD FOR MODIFYING THE PHYSICAL, RHEOLOGICAL AND THERMOMECHANICAL CHARACTERISTICS OF A POLAR THERMOPLASTIC POLYMER - Google Patents

Abstract

A method of modifying the rheological characteristics of a polar thermoplastic polymer, in particular a PET for increasing its melt viscosity while retaining and / or improving its physical and thermomechanical characteristics, of reacting said polar thermoplastic polymer with a bi-component system consisting of at least one diisocyanate of functionality greater than or equal to 2 and at least one functional polyol based on secondary alcohol greater than or equal to 5.

Description

-1- METHOD FOR MODIFYING THE PHYSICAL AND RHEOLOGICAL CHARACTERISTICS

  The invention relates to a method for modifying the rheological characteristics of a polar thermoplastic polymer for modifying its viscosity in the molten state while preserving and / or improving its physical and thermomechanical characteristics. SUMMARY OF THE INVENTION

  In the particular case of PET, but in a nonlimiting manner, the process of the invention aims to increase the viscosity of said PET without modifying its mechanical properties, in order to make it extrudable.

  In the remainder of the description and in the claims, the term "polar thermoplastic polymer" denotes a polymer having groups capable of reacting with isocyanate functions and / or alcohol functions of the polyol.

  As already stated, the invention is more particularly described in relation to the modification of PET, although it concerns the modification of any type of polar thermoplastic polymer and in particular those selected from the group comprising PET, recycled PET, PBT, PTT, PETG, PCL, PLA, polyester-based copolymers such as HYTREL and ARMITREL, polyamides such as PA6, PA 6.6, PAl 1 and PAl2, copolymers with polyamide base such as PEBAX and VESTAMID E, polyurethanes of polyester, polyether, polycarbonate, homo or copolymer POM, polycarbonates, as well as alloys containing at least one of said polar thermoplastic polymers.

  Depending on the nature of the polar thermoplastic polymer, the physical and thermomechanical modifications of said polymer may be of different kinds. This is particularly the crystallinity, the latter to act on the mechanical strength and dimensional stability. Thus, for example, one of the major disadvantages of recycled PET or PET is its low melt viscosity which prevents any extrusion of thick profile.

  The problem to be solved by the invention is therefore to develop a PET which has an improved viscosity in the molten state to make it industrially extrudable while remaining in satisfactory crystallinity levels, in practice between 20 and 30 %. It is known that below a crystallinity level of 20%, the PET loses its dimensional stability, whereas above a crystallinity level of 30%, the PET loses its mechanical strength and becomes brittle.

  The Applicant has found that, quite surprisingly, it was possible to increase the viscosity of a PET while controlling the degree of crystallinity, by reacting a specific two-component system combining a diisocyanate and a polyol having a functionality. depending on the high secondary alcohol, on said polymer.

  More specifically, the subject of the invention is a process for modifying the rheological characteristics of a polar thermoplastic polymer, aimed at modifying its melt viscosity while preserving and / or improving its physical and thermomechanical characteristics, consisting in making reacting said polar thermoplastic polymer with a two-component system consisting of at least one diisocyanate of functionality greater than or equal to 2 and at least one functional polyol based on secondary alcohol greater than or equal to 5.

  In a particular embodiment, the polar thermoplastic polymer is a PET or a recycled PET and the process aims to increase its melt viscosity to make it extrudable.

  As regards the diisocyanate, this advantageously has a functionality of between 2 and 3. The term functionality refers to the ratio between the number of moles of NCO carried by the diisocyanate and the number of moles of diisocyanate.

  Preferably, without being limiting, the diisocyanate monomer is selected from the group consisting of 2,2 '-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), tri-, -3-tetra-, penta -, hexa-, hepta and / or octamethylene diisocyanate, 2-methyl-pentamethylene diisocyanate-1,5, 2-ethylbutylene diisocyanate-1,4, pentamethylene diisocyanate-1,5, butylene diisocyanate-1,4, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI isophorone diisocyanate), 1,4- and / or 1,3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate , 1-methyl-2,4 and / or 2,6-cyclohexane diisocyanate and / or 4,4 '-, 2,4' - and 2,2'-dicyclohexylmethane diisocyanate, 1,5-naphthylene diisocyanate (NDI), 2.4 - and / or 2.6 - toluylene diisocyanate (TDI), 3,3'-dimethyl diphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or phenylene diisocyanate.

  With regard to the polyol, it has a secondary alcohol functionality greater than 5, advantageously greater than 10 and preferably greater than 40. The term functionality refers to the ratio between the number of moles of secondary OH carried by the polyol and the number of moles of polyol. Preferably, without being limiting, the polyol is an oligomer or a polymer selected from the group of polyphenoxy copolymers of bisphenol A and epichlorohydrin, homopolymers of diglycidyl ether of bisphenol A (DGEBA), polyvinyl alcohols, copolymers of ethylene and vinyl alcohol. The viscosity and the degree of crystallinity are controlled by varying the weight ratio on the one hand, of the two constituents of the two-component system and, on the other hand, of the polymer, for example PET relative to the two-component system. The modified PETs have a degree of crystallinity of between 20 and 30% and an intrinsic viscosity (IV) of between 0.75 and 1.50 dl / g (measured at 25 ° C. by capillary rheometry from a modified PET solution in a phenol dichlorobenzene mixture). 1: 1).

  In practice, the diisocyanate / polyol weight ratio is between 0.1 and 5.

  Furthermore, the two-component system advantageously represents between 0.1 and 15% by weight of the polar thermoplastic polymer. The invention also relates to modified polar thermoplastic polymers obtainable by the method described above.

  It also relates to a process for producing granules or articles molded from a polar thermoplastic polymer modified according to the method described above.

  According to this method, hot, is injected or extruded or compressed a mixture containing the polar thermoplastic polymer, diisocyanate and polyol.

  The two-component system can be injected at the same time as the polymer or separately. Similarly, the components of the two-component system can be injected together or separately.

  The transformed granules can then optionally be stored and repransformed for the manufacture of molded articles without changing viscosity, crystallinity and thermomechanical characteristics.

  The invention finally relates to the two-component system consisting of at least one diisocyanate having a functionality of between 2 and 3 and at least one polyol having a secondary alcohol functionality of greater than or equal to 5, in particular intended for be used in the previously described modification method.

  In practice, the diisocyanate / polyol weight ratio is between 0.1 and 5.

  Furthermore, the two-component system advantageously represents between 0.1 and 15% by weight of the polar thermoplastic polymer.

  Without being limiting, the diisocyanate monomer is selected from the group consisting of 2,2 '-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), tri-, tetra-, penta-, hexa-, hepta. and / or octamethylene diisocyanate, 2-methyl-pentamethylene diisocyanate-1,5, 2-ethylbutylene diisocyanate-1,4, pentamethylene diisocyanate-1,5, butylene diisocyanate-1,4, 1-isocyanato-3 , 3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI isophorone diisocyanate), 1,4- and / or 1,3-bis-5- (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 2,4-methyl and / or 2,6-cyclohexane diisocyanate and / or 4,4 '-, 2,4' and 2,2'-dicyclohexylmethane diisocyanate, 1,5-naphthylene diisocyanate (NDI), 2,4- and / or or 2.6 toluene diisocyanate (TDI), 3,3'-dimethyl diphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or phenylene diisocyanate.

  Similarly, without being limiting, the oligomeric or polymeric polyol is chosen from the group of polyphenoxy copolymers of bisphenol A and epichlorohydrin, homopolymers of DGEBA, polyvinyl alcohols, copolymers of ethylene and vinyl alcohol.

  The invention and the advantages thereof will emerge from the following examples of embodiments in support of the appended figures.

  FIGS. 1 and 2 correspond to the spectra of products TPM1, TPM2, TPM3, TPM4, TPM5 obtained by dynamic mechanical analysis (DMA) carried out at 1 Hz and 5 C / min. Figure 3 corresponds to the curves Constraint vs. deformation of the products TPM1 and TPM2 obtained during a tensile test carried out at 25 C at a speed of 50 mm / min. FIG. 4 corresponds to the spectrum of the product TPM6 obtained by DMA carried out at 1 Hz and 5 C / min. Figure 5 corresponds to the Constraint vs curve. deformation of the product TPM6 obtained during a fraction test carried out at 25 ° C. at a speed of 50 mm / min. Figure 6 corresponds to the Constraint vs curve. deformation of the product TPM7 obtained during a fraction test carried out at 25 C at a speed of 50 mm / min.

  FIG. 7 corresponds to the spectra of the product TPM8 obtained by DMA carried out at 1 Hz and 5 C / min.30 EXAMPLES

  Presentation of Examples The set of modified polar thermoplastic materials (hereinafter referred to by the term TPM) presented here to illustrate the invention, were prepared in twin screw extruder (Diameter 26 / 50D). The temperature control of the extruder is provided by 10 separate heating elements (10 heating zones denoted Z1 to z10). The temperature profile used for each example is given in Table 1 (Temperatures expressed in C). Table 1 Material rZ1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10 TPM1 260 280 280 260 260 260 260 260 260 260 TPM2 260 280 280 260 260 260 260 260 260 260 TPM3 260 280 280 260 260 260 260 260 260 260 TPM4 260 280 280 260 260 260 260 260 260 260 TPM5 260 280 280 260 260 260 260 260 260 260 TPM6 230 250 250 250 230 230 230 230 230 230 TPM7 190 190 190 190 190 190 190 190 190 TPM8 240 280 280 260 260 260 260 260 260 Examples 1 to 5 (TPM1 to TPM5) These first five examples are manufactured and recycled PETs modified by the two-component system.

  The first (TMP1) is obtained from PET EASTAR 9921W modified in the presence of 8 per PKHH and 4 per SUPRASEC 1400. PKHH is a polyphenoxy copolymer of bisphenol A and epichlorohydrin molar mass in a number equal to 13000 g / mol. Its functionality is about 50. The hydroxyl functions are secondary OHs. The SUPRASEC 1400 is a MDI 4,4 'with functionality equal to 2.

  The second (TMP2) is obtained from PET EASTAR 9921W modified in the presence of 4 per PKHH and 2.5 per SUPRASEC 1400. The third (TMP3) is obtained from PET EASTAR 9921W modified in presence of 2 per PKHH and 4 per SUPRASEC 1400.

  The fourth (TMP4) is obtained from modified PET waste in the presence of 4% PKHH and 2.5% SUPRASEC 1400.

  The fifth (TMP5) is obtained from PET waste modified in the presence of 2 per PKHH and 1.5 per SUPRASEC 1400.

  For these five examples, PET and polyol are introduced into the extruder together at the extruder head (main feed). The MDI is incorporated as a second entrance (located about 25D).

  Example 6 (TPM6) Example 6 corresponds to a TPM based on HYTREL, a polyester elastomer. This TPM6 is obtained from HYTREL 5526 modified in the presence of 4 per PKHH and 2.5 per SUPRASEC 1400

  Example 7 (TPM7) Example 7 corresponds to a TPM based on polyamide 12 This TPM7 is obtained from GRILAMID L25A NZ modified in the presence of 4 per PKHH and 2 per SUPRASEC 1400.

  Example 8 (TPM8) Example 8 corresponds to a TPM based on polyacetal copolymer (POM). This TPM8 is obtained from Schulaform 9 modified in the presence of 1 per PKHH and 2 per SUPRASEC 1400.

  For these three examples, the thermoplastic, polyol and diisocyanate are introduced into the extruder together at the extruder head (main feed). In order to evaluate the performance of the modified thermoplastics, the granules were shaped by compression molding or by injection molding. The conditions of implementation are shown in Table 2 below.

  Table 2 Compression molding Injection molding Material Temperature (C) Pressure (Bar) Temperature Temperature mold material (C) (C) TPM 1 to TPMP5 260 20 260 140 TPM6 230 20 230 70 TPM7 260 20 260 60 TPM8 190 20 190 50 Performance of the modified thermoplastics Examples 1 to 5

  From the five examples of PET modified by the two-component system, Table 3 presented below shows the possibility of adjusting the viscosity of PET, including the values of MFI (Melt Flow Index) or IV (intrinsic viscosity). give a reading, by controlling the degree of crystallinity without lowering the melting temperature.

  Table 3 MFI Material * (g ~ 10min) IV Crystallinity Rate ** (dl / g) Melt Matte (C) (%) EASTAR 9921 W 70 252 50 0.75 PET Waste 110 - - 0.60 TPM1 12 249 26 1.25 TPM2 22 249 26 0.92 TPM3 <1 246 24 1.57 TPM4 5 245 24 1.15 TPM5 30 249 25 0.9 * Measured at 260 C under a load of 10 kg ** Measured by capillary rheometry at 25 C from solution of PET in a mixture The thermomechanical properties of the modified PETs are comparable to that of the EASTAR 9921W reference PET (see spectra shown in FIGS. 1 and 2 obtained by dynamic mechanical analysis (DMA) carried out at 1 Hz and 5 MHz. C / min). The modules in the rubbery state are maintained or even increased despite the lower crystallinity levels (about 25% for the modified PET instead of 50% for the reference PET). In addition, the mechanical relaxation temperature Alpha associated with the glass transition increases by about 15 C (110 C instead of 95 C for the reference PET).

  Finally, the elongation at break of the modified PET is considerably increased compared to the reference PET tested under the same conditions (see curves shown in FIG. 3 obtained during a fraction test carried out at 25 C at a speed of 50 mm / min). For example, modified 9921W PETs TPM1 and TPM2 have elongations at break of 110% and 310% instead of 45%, respectively, for the unmodified 9921W PET.

Example 6

  As in the case of PET, the two-component system increases the viscosity of HYTREL 5526 (see Table 4 below). The degree of crystallinity decreases by about 17% without decreasing the melting temperature.

  Table 4 Materials HYTREL 5526 TPM 6 Maté MFI (g / l0min) 40 12 Melting temperature (C) 201 200 Melting enthalpy (Fg) 35 29 * Measured at 230 C under a load of 10 kg 25 Thermomechanical properties of the HYTREL 5526 modified are comparable to that of the unmodified polymer (see DMA spectra made at 1 Hz and 5 C / min shown in Figure 4). On the other hand, the breaking stress and elongation at break of the modified HYTREL 5526 (37 MPa and 960% elongation) are considerably increased compared to the unmodified polymer (21 MPa and 680% elongation). ), tested under the same conditions (see curves shown in FIG. 5 obtained during a fraction test carried out at 25 ° C. at a speed of 50 mm / min).

  EXAMPLE 7 Unlike PET, modification of PAl 2 by the two-component system results in fluidization of the polymer with a decrease in viscosity without changing thermal properties as shown in Table 5 below.

  The mechanical strength of the modified PAl 2 is considerably increased with, for example, in the case of PAl 2 modified TPM 7, an elongation at break of 340% instead of 45% for an equivalent breaking stress equal to approximately 27 MPa (see curves). shown in Figure 6 obtained in a tensile test performed at 25 C at a speed of 50 mm / min). Table 5 Materials GRILAMIDeL25ANZ TPM 7 MFI Mat (g / 10min) 5 68 Melting Point (C) 178 178 Melting Enthalpy (Fg) 32 30 * Measured at 230 ° C under a load of 22 kg Example 8 Modification of POM by the two-component system causes an increase in the viscosity of the polymer without changing the thermal properties as shown in Table 6 below. Table 6 Materials Schulaforme'9 TPM 8 Maté MFI (g / l0min) 5.8 3.7 Melting temperature (C) 164 167 Melting enthalpy (Fg) 131 137 25 * Measured at 190 C under a load of 2.16 kg -11- The modification leads to an improvement in thermomechanical properties as shown by the DMA spectra produced at 1 Hz and 5 C / min shown in FIG. 7. The module with rubber plateau is more stable in temperature and its fall is delayed. The deflection temperature under a load of 1.8 MPa (HDT A) is shifted by 15 C (130 C instead of 115 C). The continuous resistance temperature of the modified POM is increased. The TPM8 is able to hold continuously at a temperature of 120 C against 100 C for the unmodified POM.

15 20 25 30

Claims (3)

  1 / A method for modifying the rheological characteristics of a polar thermoplastic polymer, aimed at modifying its melt viscosity while retaining and / or improving its physical and thermomechanical characteristics, of reacting said polar thermoplastic polymer with a system bi-component consisting of at least one diisocyanate of functionality greater than or equal to 2 and at least one functional polyol based on secondary alcohol greater than or equal to 5. 2 / Process according to claim 1, characterized in that the polymer Polar thermoplastic is a recycled PET or PET, said process for increasing the viscosity of PET or PET recycled in the molten state while maintaining and / or improving its physical and thermomechanical characteristics.  3 / A method according to claim 1, characterized in that the polar thermoplastic polymer is selected from the group comprising PBT, PTT, PETG, PCL, PLA, copolymers based on polyester, polyamides such as PA6 PA 6.6, PAl 1 and PAl 2, copolymers based on polyamide, polyurethanes of polyester, polyether, polycarbonate type, homo or copolymeric POMs, polycarbonates, and alloys containing at least one of said polar thermoplastic polymers. . 4 / A method according to claim 1, characterized in that the diisocyanate has a functionality of between 2 and 3. 5 / A method according to claim 1, characterized in that the diisocyanate is selected from the group consisting of   2.2 '-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), tri-, tetra-, penta-, hexa-, hepta and / or octamethylene diisocyanate, 2-methyl-pentamethylene diisocyanate-1,5 , 2-ethylbutylene-1,4-diisocyanate, 1,5-pentamethylene diisocyanate, 1,4-butylene diisocyanate, 1,3-isocyanato-3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI isophorone diisocyanate), 1,4 and / or 1,3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4 and / or 2,6-cyclohexane diisocyanate and / or 4, 4 ', 2,4' and 2,2'-dicyclohexylmethane diisocyanate, 1,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-toluylene 15-13-diisocyanate (TDI),   3,3'-dimethyl diphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or phenylene diisocyanate. 6 / A process according to claim 1, characterized in that the polyol has a functionality, as a secondary alcohol function greater than 5, advantageously greater than 10 and preferably greater than 40 7 / Process according to claim 1, characterized in that the Polyol is an oligomer or a polymer selected from the group consisting of polyphenoxy copolymers of bisphenol A and epichlorohydrin, homopolymers of DGEBA, polyvinyl alcohols, copolymers of ethylene and vinyl alcohol. 8 / A method according to claim 1, characterized in that the diisocyanate / polyol weight ratio is between 0.1 and 5. 9 / The method of claim 1, characterized in that the two-component system is between 0.1 and 15% by weight polar thermoplastic polymer. 10 / A method according to claim 1, characterized in that the constituents of the bi-component system are incorporated together or separately. 11 / Modified polar thermoplastic polymer obtainable by the process according to one of claims 1 to 10. 12 / Polymer according to claim 11, characterized in that the polar thermoplastic polymer is chosen from the group comprising PET , recycled PET, PBT, PTT, PETG, PCL, PLA, polyester-based copolymers, polyamides such as PA6, PA 6.6, PA11 and PAl2, polyamide-based copolymers polyurethanes of polyester, polyether, polycarbonate type, homo or copolymeric POMs, polycarbonates, as well as alloys containing at least one of said polar thermoplastic polymers. 25-14- 13 / Two-component system consisting of at least one diisocyanate of functionality between 2 and 3 of at least one polyol having a secondary alcohol functionality greater than or equal to 5, in particular for use in the method according to one of claims 1 to 10.  14 / Two-component system according to claim 13, characterized in that the weight ratio diisocyanate / polyol is between 0.1 and 5 15 / Two-component system according to claim 13, characterized in that the diisocyanate is selected from the group including 2.2 '-, 2.4'- and / or   4,4'-diphenylmethane diisocyanate (MDI), tri-, tetra-, penta-, hexa-, hepta and / or octamethylene diisocyanate, 2-methyl-pentamethylene diisocyanate-1,5, 2-ethylbutylene diisocyanate-1,4 1,5-pentamethylene diisocyanate, 1,4-butylene diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI isophorone diisocyanate), 1,4- and / or 1, 3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4 and / or 2,6-cyclohexane diisocyanate and / or 4,4 '-, 2,4' and 2.2 dicyclohexylmethane diisocyanate, 1,   5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-toluylene diisocyanate (TDI), 3,3'-dimethyl diphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or phenylene diisocyanate. The bi-component system according to claim 13, characterized in that the polyol is an oligomer or a polymer selected from the group consisting of polyphenoxy copolymers of bisphenol A and epichlorohydrin, homopolymers of DGEBA, polyvinyl alcohols, copolymers of ethylene and vinyl alcohol. 17 / A method of manufacturing granules or articles molded from a polar thermoplastic polymer modified according to the method according to one of claims 1 to 10 wherein, hot, is injected or extruded or compressed a mixture containing the polar thermoplastic polymer, the diisocyanate and the polyol. 30