HIGH-RESILIENCY RIGID COMPOSITE MATERIALS, AND USE AND PRODUCTION THEREOF

Abstract

A process for the production of high-resiliency rigid composite material includes the steps of mixing and dispersing compounds in a molten state in a mixer. The compounds include polymers of isotactic propylene, modifying polymers, compatibility promoters, additives, and fillers, wherein the fillers have unit component dimensions in the range of 10.sup.3 mm-10.sup.6 mm and the process provides for a temperature in the range of 120-230 C. and a rotation rate of the screws that compose the mixer comprised in the range of 125-1250 rpm. The disclosure further relates to a high-resiliency rigid composite material and uses thereof

Claims

1-7. (canceled)

8. A process for the production of high-resiliency rigid material, comprising the step of mixing and dispersing in a molten state in a mixer the following compounds: polymers of isotactic propylene, selected from the group constituted by: propylene homopolymers and propylene copolymers; modifying polymers selected from the group constituted by: polymers of poly alpha olefins (POE), ethylene propylene rubbers (EPR), ethylene propylene dimer rubbers (EPDM); compatibility promoters selected from the group constituted by: olefin polymers functionalized with maleic anhydride, olefin polymers functionalized with silanes, ethylene-acrylic acid (EAA) copolymers, polycaprolactones; additives selected from the group constituted by: phenols, phosphites, ethers, thioethers, benzophenones, benzotriazole derivatives, sterically hindered amines, halogenated additives, melamines, melamine salts, salts of phosphorus derivatives, glyceryl monostearate, stearic salts of calcium, stearic salts of zinc, organic compounds, inorganic salts, inorganic oxides, carbon blacks; and fillers selected from the group constituted by: inorganic fillers having an isotropic structure and fillers having an anisotropic structure; wherein said fillers have unit component dimensions comprised in the range of 10.sup.3 mm-10.sup.6 mm; and wherein said process provides for: a temperature comprised in the range of 120-230 C.; and a rotation rate of the screws that compose said mixer comprised in the range of 125-1250 rpm.

9. The process according to claim 8, wherein said step of mixing and dispersing in the molten state occurs gravimetrically or volumetrically.

10. The process according to claim 8, wherein: said propylene homopolymers are present in the range of 45-85% by weight; said propylene copolymers are present in the high-resiliency rigid composite material in the range of 45-90% by weight; said poly alpha olefin (POE) polymers are present in the range of 10-30% by weight; said ethylene propylene rubbers (EPR) are present in the range of 5-20% by weight; said ethylene propylene dimer rubbers (EPDM) are present in the range of 5-20% by weight; said olefin polymers functionalized with maleic anhydride comprise maleic anhydride that is present in the range of 0.5-0.8% by weight; said olefin polymers functionalized with maleic anhydride are present in the range comprised between 2 and 5% by weight; said olefin polymers functionalized with silanes are present in the range of 0.5-5% by weight; said ethylene acrylic acid (EAA) copolymers are present in the range of 6-12% by weight; said polycaprolactones are present in the range of 0.5-2% by weight; said additives are present in the range comprised between 0.1 and 0.5% by weight; said inorganic fillers with isotropic structure are selected from the group constituted by: high purity micronized talc in calcium and magnesium silicates, and calcium carbonate; where: said micronized talc with high purity in silicates of calcium and magnesium is present in the range of 0.5-12% by weight; said calcium carbonate has the form of a nanofiller and is present in the range of 0.1-7.5% by weight; and said fillers with anisotropic structure are selected from the group constituted by carbon nanotubes and glass fiber and are present in the range between 0.5 and 7.5% by weight.

11. The process according to claim 8, wherein: said polymers of isotactic propylene are copolymers of propylene in blocks, with an average content of ethylene, present in a percentage equal to 71.7% by weight of the total, said modifier polymers are polymers of poly alpha olefins (POE), with crystalline phase, present in a percentage equal to 20.5% by weight of the total, said compatibility promoters are olefin polymers functionalized with maleic anhydride, present in a percentage equal to 2.5% by weight of the total, said additives are selected from the group constituted by: phenols, phosphites, thioethers, and are present in a percentage equal to 0.3% by weight of the total, and said fillers are constituted by nano calcium carbonate, present in a percentage equal to 5% by weight of the total.

12. A high-resiliency rigid composite material, comprising: polymers of isotactic propylene, selected from the group constituted by: propylene homopolymers and propylene copolymers; modifying polymers selected from the group constituted by: polymers of poly alpha olefins (POE), ethylene propylene rubbers (EPR), ethylene propylene dimer rubbers (EPDM); compatibility promoters selected from the group constituted by: olefin polymers functionalized with maleic anhydride, olefin polymers functionalized with silanes, ethylene-acrylic acid (EAA) copolymers, polycaprolactones; additives selected from the group constituted by: phenols, phosphites, ethers, thioethers, benzophenones, benzotriazole derivatives, sterically hindered amines, halogenated additives, melamines, melamine salts, salts of phosphorus derivatives, glyceryl monostearate, stearic salts of calcium, stearic salts of zinc, organic compounds, inorganic salts, inorganic oxides, carbon blacks; fillers selected from the group constituted by: inorganic fillers having an isotropic structure and fillers having an anisotropic structure; and wherein said fillers have unit component dimensions comprised in the range of 10.sup.3 mm-10.sup.6 mm.

13. The material according to claim 12, wherein: said propylene homopolymers are present in the range of 45-85% by weight; said propylene copolymers are present in the high-resiliency rigid composite material in the range of 45-90% by weight; said poly alpha olefin (POE) polymers are present in the range of 10-30% by weight; said ethylene propylene rubbers (EPR) are present in the range of 5-20% by weight; said ethylene propylene dimer rubbers (EPDM) are present in the range of 5-20% by weight; said olefin polymers functionalized with maleic anhydride comprise maleic anhydride that is present in the range of 0.5-0.8% by weight; said olefin polymers functionalized with maleic anhydride are present in the range comprised between 2 and 5% by weight; said olefin polymers functionalized with silanes are present in the range of 0.5-5% by weight; said ethylene acrylic acid (EAA) copolymers are present in the range of 6-12% by weight; said polycaprolactones are present in the range of 0.5-2% by weight; said additives are present in the range comprised between 0.1 and 0.5% by weight; said inorganic fillers with isotropic structure are selected from the group constituted by: high purity micronized talc in calcium and magnesium silicates, and calcium carbonate; where: said micronized talc with high purity in silicates of calcium and magnesium is present in the range of 0.5-12% by weight; said calcium carbonate has the form of a nanofiller and is present in the range of 0.1-7.5% by weight; and said fillers with anisotropic structure are selected from the group constituted by carbon nanotubes and glass fiber and are present in the range between 0.5 and 7.5% by weight.

14. The material according to claim 12, wherein: said polymers of the isotactic propylene are copolymers of propylene in blocks, with an average content of ethylene, present in a percentage equal to 71.7% by weight of the total, said modifying polymers are polymers of poly alpha olefins (POE), with crystalline phase, present in a percentage equal to 20.5% by weight of the total, said compatibility promoters are olefin polymers functionalized with maleic anhydride, present in the percentage equal to 2.5% by weight of the total, said additives are selected from the group constituted by: phenols, phosphites, thioethers, and are present in a percentage equal to 0.3% by weight of the total, and said fillers are constituted by carbon nanotubes that are present in a percentage equal to 5% by weight of the total.

15. Use of the high-resiliency rigid composite material according to claim 12 for sheets for thermoforming by extrusion, injection molding of technical cases, molding of containers for electrical/electronic instruments, injection molding of mechanical instruments, injection molding for containers for protecting electronic systems and for appliances, injection molding of components for the automotive sector.

Description

EXAMPLES

1 Rigidity and Resiliency

[0214] Table 1 lists some characteristics of polypropylene without and with ethylene comonomer in various concentrations: the polymers being considered have comparable fluidity values and their predominant technological destination relates to their transformation by injection molding.

[0215] All the polypropylene types exemplified in Table 1 have impact resistance characteristics that are insufficient to be polymeric matrices that are interesting for being modified with fillers and/or reinforcements, the purpose of which is to reach higher rigidity values.

[0216] The aim of the present disclosure is to modify the polypropylene matrix in order to obtain an optimum performance balance so as to manufacture products that require high rigidity and impact resistance values at the same time.

TABLE-US-00001 TABLE 1 Physical-mechanical behavior of polypropylene homopolymer and of polypropylene containing ethylene comonomer. PROPERTIES OF DIFFERENT TYPES OF POLYPROPYLENE 13/258- 13/267- 13/267- 13/217- polymeric matrices reference 2 5 1 1 Moplen V 30 G PP 100 homopolymer Clyrell EC 340 Q PP copolymer 100 high-resiliency PP Ineos 500 GA nat. PP copolymer 100 in blocks Dow Inspire PPc 706-21 PP copolymer 100 NA/HP in blocks total 100 100 100 100 specimen provision technology injection molding from granules CHARACTERIZATION tensile strength ISO 527 yield strength v = 5 mm/ MPa 32.9 23 20.6 26.6 yield point elongation 8.5 13 6.8 5.1 ultimate tensile strength MPa not determined breaking elongation % >350 >350 >350 >250 tensile modulus v = 1 mm/ MPa 1,852 1,150 1,308 1,767 (Young's modulus) impact resistance ISO 180 1/A Impact IZOD at 23 C.-with notch KJ/m.sup.2 4.1 22 47.2 8.3 Impact IZOD at 20 C.-with notch KJ/m.sup.2 1.7 4.3 9.5 4.8 Fluidity = MFI ISO 1133 g/10 20.1 22 18.3 22.1

2 Modification of Performance by Using High-Resiliency Polymers

[0217] Ethylene-propylene copolymers with appropriate rheology in the molten state, among these in particular those with a partially crystalline morphology such as POE (Poly Olefin Elastomers), if used in concentrations compatible with the preservation of suitable rigidity values, provide the thermoplastic matrices of polypropylene nature with important benefits in terms of increasing their impact resistance.

[0218] The innovative elements reside: [0219] in the choice of polymeric modifiers, which have a viscosity in the molten state that is high enough to allow their dispersion and distribution in the thermoplastic matrix [0220] in the use of compatibility promoters which, by improving affinity between the matrix phase and the modifier phase, are capable of avoiding coalescence phenomena during transformation to the molten state in the presence of high flow gradients [0221] in the use of fillers, which supports the reduction in rigidity as a consequence of the use of the modifying polymers with elastomeric behavior (such as POE).

[0222] The following Table 2 exemplifies the variations undergone by matrices of polypropylene (PP) with POE modifiers.

TABLE-US-00002 TABLE 2 Effects of the addition of elastomeric modifier on PP copolymer matrices. PROPERTIES OF MIXTURES OF DIFFERENT TYPES OF POLYPROPYLENE WITH POE reference 13/267-1 13/217-1 13/258-6 13/258-1 polymeric matrices PP Ineos 500 GA nat. copolymer 100 60 in blocks Dow Inspire PPc 706-21 NA/HP PP 100 31 77.6 copolymer in blocks polymeric modifier for resiliency increase Dow Affinity EG 8200 (POE) Poly Olefin 9 22.4 Elastomer total 100 100 100 100 Type of mixing in extruder none none molten molten specimen provision technology injection molding from granule CHARACTERIZATION tensile strength ISO 527 yield strength v =5 mm/ MPa 20.6 26.6 18.6 17.1 yield point elongation 6.8 5.1 7.5 7.5 ultimate tensile strength MPa breaking elongation % >350 >250 >350 >350 tensile modulus (Young's v = 1 mm/ MPa 1,308 1,767 1,134 1,322 modulus) impact resistance ISO 180 1/A Impact IZOD at 23 C.-with notch KJ/m.sup.2 47.2 8.3 44.1 48.9 Impact IZOD at 20 C.-with notch KJ/m.sup.2 9.5 4.8 10 47.1 Fluidity = MFI ISO 1133 g/10 18.3 22.1 16.6 13.8

3 Addition of Fillers

[0223] As described above, in order to compensate for the loss in rigidity caused to the PP matrix by the use of resilient polymeric modifiers, inorganic fillers are used. These fillers impart different effects as a consequence: [0224] of the nature of the filler; [0225] of the morphology and particle size of the filler; [0226] of the distribution and dispersion effectiveness of the filler in the matrix polymer; [0227] of the use of compatibility promoters, the effectiveness of which depends: [0228] on the variation of the surface tension of the filler [0229] on the possibility of providing bonds, even low-energy bonds (such as hydrogen bonds), between the filler and the polymeric system.

[0230] The innovative elements of the present disclosure reside: [0231] in the use of micron (micrometer) and submicron (angstrom) size fillers; [0232] in the management of the compounding process parameters (high shear for short times); [0233] in the use of compatibility promoters with maleic anhydride and/or of a silane nature and/or of polycaprolactones.

[0234] The following Table 3 exemplifies the beneficial effects achieved on the performance of a PP matrix with simultaneous use: [0235] a) of impact resistance modifier (POE polymer); [0236] b) of calcium carbonate in elementary form of a few micrometers (10.sup.6 meters) or of a few angstrom (10.sup.10 meters) of a compatibility promoter with functions as a modifier of the tension of the surfaces of the polymer, of the modifier and of the filler (functionalized with maleic anhydride).

TABLE-US-00003 TABLE 3 Effect on the performance of PP for use as an impact modifier, filler and compatibility promoter. formulation reference DESCRIPTION a) 11/256-1 copo PP/POE/maleic adduct/nanoCaCO.sub.3 b) 11/256-2 copo PP/POE/CaCO.sub.3 a) b) TEST components % matrix polymer PPC Inspire 706-21 NA HP nat PP 72.6 70.6 polymeric modifier Engage 8842 nat. POE 20.4 19.4 filler Nano CaCO.sub.3 nano filler 5 CaCO.sub.3 filler filler 10 compatibility promoter Compoline CO/LA-MF maleic adduct 2 MECHANICAL PROPERTIES METHOD UNIT Yield strength MPa 17.5 16.7 Ultimate tensile strength ASTM D 638 MPa n/a n/a Breaking elongation % >350 >350 Tensile modulus MPa 1190 1432 Flexural modulus ASTM D 790 MPa 986 1177 Maximum flexural load MPa 23.3 26.8 IZOD with notch at 23 C. ASTM D 256 J/m 716.1 573.7 impact without notch at 23 C. J/m NB NB with notch at 20 C. J/m 404.2 143.7 THERMAL PROPERTIES HDT 1820 KPa ASTM D 648 C. 76.8 93.4 PHYSICAL PROPERTIES Ash 1 h at 630 C. % 4.9 10.1 MFI 216 Kg 230 C. ASTM D 1238 g/10 13.3 14.5

[0237] The performance set of composite materials containing a polypropylene matrix, a polymeric modifier and variable percentages of talc filler in micronized form, shown in the following Table 4, provides evidence of the containment of the resiliency loss together with the increase in rigidity.

[0238] Types of talc with different particle size, dispersed and distributed during mixing in the molten state in a matrix of PP modified with elastomeric polymer, contribute differently to the performance blend of rigidity and resiliency, usually associating lower rigidity with a higher resiliency value.

[0239] According to the results of the present disclosure it is possible to associate a better balance of rigidity and resiliency with equal density by using the same mixing technology, the same combination of PP matrix and modifier, using a more micronized talc filler.

[0240] Innovative elements with respect to current knowledge are constituted by the results, obtained by the use in the matrix of PP modified with POE with the prospect of improving resiliency without a significant loss in rigidity, of different concentrations of nanofiller of calcium carbonate, as shown in Table 6.

[0241] The PP matrices, improved in their resiliency by adding elastomeric polymers (POE), are interesting polyphasic systems capable of containing nanoreinforcements (carbon nanotubes), with the prospect of increasing rigidity and obtaining an antistatic behavior, as is evident from the examination of the performance listed in Table 7.

[0242] For high contents of carbon nanotubes, electrically conducting thermoplastic composite materials are obtained which have a shielding effect against radio frequencies and electromagnetic waves.

[0243]

[0244] material, a high-resiliency rigid composite material, and uses thereof