Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms
  • C08L23/0815—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms with aliphatic 1-olefins containing one carbon-to-carbon double bond
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/16—Ethene-propene or ethene-propene-diene copolymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2314/00—Polymer mixtures characterised by way of preparation
  • C08L2314/02—Ziegler natta catalyst

Definitions

• the present invention relates to an impact resistant thermoplastic polyolefin composition.
• the present invention relates to a composition containing a propylene polymer component, a copolymer of ethylene with C4-C10 a-olefms, other polyolefin elastomeric or plastomeric materials and a filler material.
• thermoplastic polymer compositions to combine propylene polymers, generally homopolymers or copolymers with minor amounts of comonomers, with elastomeric ethylene copolymers, to achieve a useful balance of rigidity (high flexural modulus) and impact resistance.
• rigidity high flexural modulus
• impact resistance elastomeric ethylene copolymers
• polyolefin compositions with low values of thermal shrinkage and good mechanical properties comprising a propylene polymer component, a copolymer of ethylene with one or more C4-C10 a-olefms, other elastomeric or plastomeric polyolefms and mineral fillers.
• flexural modulus values significantly higher than 1000 MPa are obtained only by adding around 20% by weight of mineral fillers.
• melt flow rate (MFR) of the compositions with high values of flexural modulus is relatively low.
• the polyolefin composition of the present invention finds application above all in the automotive field, in particular in the preparation of door trims.
• composition comprising, all percentages being by weight:
• copolymer includes polymers containing more than one kind of comonomers.
• composition of the present invention can also optionally comprise a nucleating agent F), in preferred amounts of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of A) + B) + C) + D) and optionally E).
• a nucleating agent F in preferred amounts of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of A) + B) + C) + D) and optionally E).
• composition of the present invention has preferably a MFR value of 20 g/10 min. or higher, or even of 23 g/10 min. or higher, for example in the range from 20 to 60 g/10 min., in particular from 23 to 60 g/10 min.
• composition of the present invention can be easily converted into various kinds of finished or semi-finished articles, in particular by using injection-molding techniques, due to its relatively high values of MFR, associated with the said high balance of properties.
• the MFRL value of component A) can result from mixing various propylene homoplymers and/or copolymers with different MFRL values.
• WA 1 and WA 2 represent the weight of components A 1 ) and A 2 ) respectively
• MFR A represent the calculated value of MFR for A)
• MFR 1 and MFR 2 represent the MFR of components A 1 ) and A 2 ) respectively.
• the MFRL value of a single polymer can therefore be even lower than 90g/10 min.
• MFRL value of component A includes also the said calculated value.
• the amount of fraction (XI) insoluble in xylene at room temperature of component B) preferably satisfies the following equation:
• B 2 is the amount of ethylene in component B), expressed as percent by weight with respect to the weight of B).
• component (A) which is soluble in xylene at room temperature is, as previously said, equal to or lower than 20%, preferably equal to or lower than 10%> by weight.
• the copolymer of propylene (ii) contains at least 90% propylene, and has a preferred solubility in xylene at room temperature of lower than 15% by weight, more preferably lower than 10%, and even more preferably lower than 8%.
• Said ⁇ -olefm is preferably ethylene, butene-1, pentene-1, 4-methylpentene-l, hexene-1, octene-1 or any combinations thereof, and even more preferably the copolymer of propylene (ii) is a copolymer of propylene and ethylene.
• the components (B) and (E) are partially soluble in xylene at room temperature.
• the content of fraction of component (B) or (E) which is soluble in xylene at room temperature is preferably of about 50-95%) by weight, more preferably 55-95%) by weight.
• Illustrative C 4 -C10 a-olefins for component (B) include 1-butene, 1-pentene, 1-hexene, 4- methyl-l-pentene and 1-octene, with 1-butene being particularly preferred.
• the composition of the present invention can be prepared by melt-blending components (A), (B), (C) and (D) and optionally (E) and/or (F).
• composition of the present invention can also be prepared by subjecting to melt-blending with the other polyolefm components, the component (D) and optionally (F), a masterbatch composition (I) comprising, all percentages being by weight:
• a 1 from 60 to 85% of a polypropylene component comprising a propylene homopolymer or a propylene copolymer with another ⁇ -olefm or combinations thereof, said polypropylene component containing at least 85% by weight of propylene, and having a MFRL value equal to or higher than 20 g/10 min.
• B 1 from 15 to 40% of a copolymer of ethylene and one or more C4-C10 a-olefm(s), containing 15-35%) by weight of C4-C10 a-olefm(s) and having a solubility in xylene at room temperature greater than 50% by weight, the intrinsic viscosity of the xylene soluble fraction being from 2.5 to 4 dl/g.
• the masterbatch composition (I) has a value of melting enthalpy AHm of the DSC melting peak detectable at a temperature between 100 and 130°C of 1 J/g or more.
• the elastomeric or plastomeric polymer or polymers C) can be any elastomeric or plastomeric polymer or polymer composition commonly used to modify the mechanical properties of polyolefins.
• plastomeric is used to include the particular class of materials having properties intermediate to those of thermoplastic and elastomeric materials, generally called "plastomers". Said plastomers can have a broad range of densities (up to about 0.925 g/cm 3 ) and a higher crystallinity than the traditional elastomers.
• the said component C) preferably has at least one of the following features, in addition to the said Shore A hardness value equal to or lower than 90 points:
• - Flexural modulus (ISO 178A) equal to or less than 200 MPa, preferably equal to or less than 170 MPa, most preferably equal to or less than 100 MPa;
• - Shore D hardness equal to or less than 50 points, more preferably equal to or less than 45 points and most preferably equal to or less than 32 points;
• - X-ray crystallinity from 0 to 40%, more preferably from 0 to 30%.
• ethylene copolymers containing up to 45% by weight, in particular from 10 to 42% by weight, of an olefin comonomer, preferably a C3-C10 a-olefm, in particular butene-1 or octene-1, and having Shore A hardness of 90 points or less.
• an olefin comonomer preferably a C3-C10 a-olefm, in particular butene-1 or octene-1, and having Shore A hardness of 90 points or less.
• propylene copolymers containing up to 40% by weight of an olefin comonomer, preferably ethylene or a C4-C10 a-olefm, and having Shore A hardness of 90 points or less.
• an olefin comonomer preferably ethylene or a C4-C10 a-olefm, and having Shore A hardness of 90 points or less.
• the said ethylene copolymers 1) have typically a density from 0.86 to 0.925 g/cm 3 .
• copolymers 1 A specific example of copolymers 1) is a copolymer containing 63.5 wt% of ethylene and
• Shore A points a melting point of 60°C, a MFR of 30 g/10 min. (ASTM D 1238, 190°C/2.16 kg), an intrinsic viscosity of 0.9 dl/g and a density of 0.87 g/ml according to method ASTM D
• copolymers 1 Another specific example of copolymers 1) is a copolymer containing 62 wt% of ethylene and
• copolymers 1 Another specific example of copolymers 1) is a copolymer containing 61 wt% of ethylene and
• copolymers 1 Another specific example of copolymers 1) is a copolymer of ethylene and butene-1, having a hardness of 56 Shore A points, melting point of 36°C, a density of 0.86 g/cm 3 according to method ASTM D 792, a MFR of 1.2 g/10 min (ASTM D 1238, 190°C/2.16 kg) and an intrinsic viscosity of 1.5 dl/g.
• copolymers 1 is a copolymer of ethylene and butene-1, having a hardness of 30 Shore D points, 85 Shore A points, flexural modulus of 22.8 MPa (ASTM D 790), melting point of 60°C, a density of 0.88 g/cm 3 according to method ASTM D 792 and an intrinsic viscosity of 1.6 dl/g.
• propylene copolymers 2 are the propylene copolymers containing from 0.1 to 40% by weight, more preferably from 0.1 to 25% by weight of olefin comonomers, in particular ethylene.
• the said propylene copolymers 2) have typically a density from 0.850 to 0.890 g/cm 3 , in particular from 0.855 to 0.885 g/cm 3 . They generally display no or relatively low degree of crystallinity, indicatively from 0 to 25% when measured as X- ray crystallinity.
• - Shore A hardness preferably equal to or less than 88 points, more preferably equal to or less than 75 points;
• DSC differential scanning calorimetry
• Suitable propylene copolymers 2 are the plastomers Vistamaxx® and Versify® made available on the market by ExxonMobil Chemical and Dow Chemical, and the Notio® polymers, made available on the market by Mitsui Petrochemical.
• the said copolymers 1) and 2) are typically produced by polymerization in the presence of single site, in particular metallocene and constrained geometry catalysts.
• Such copolymers have typically intrinsic viscosity values of 2 dl/g or less. Such intrinsic viscosity values substantially correspond to the intrinsic viscosity values of the fraction soluble in xylene at room temperature, due to the very high solubility of said copolymers.
• the components (A), (B), (C) and (E) can be prepared separately by using known polymerization processes.
• the said masterbatch composition (I) can advantageously be prepared by a sequential polymerization, comprising at least two sequential steps, wherein components (A 1 ) and (B 1 ) are prepared in separate subsequent steps, operating in each step, except the first step, in the presence of the polymer formed and the catalyst used in the preceding step.
• the catalyst is added only in the first step, however its activity is such that it is still active for all the subsequent steps.
• the polymerization which can be continuous or batch, is carried out following known techniques and operating in liquid phase, in the presence or not of inert diluent, or in gas phase, or by mixed liquid-gas techniques.
• Reaction time, pressure and temperature relative to the polymerization steps are not critical, however it is best if the temperature is from 50 to 100 °C.
• the pressure can be atmospheric or higher.
• the regulation of the molecular weight is carried out by using known regulators, hydrogen in particular.
• the said polymerizations are preferably carried out in the presence of stereospecific Ziegler-Natta catalysts.
• component B) is preferably prepared by using a Ziegler-Natta catalyst in polymerization
• component C) is preferably prepared by using a single site catalyst in polymerization.
• the said catalysts are known in the art.
• chain transfer agents e.g. hydrogen or ZnEt 2
• chain transfer agents e.g. hydrogen or ZnEt 2
• Ziegler-Natta catalysts are the supported catalyst systems comprising a trialkylaluminium compound, optionally an electron donor, and a solid catalyst component comprising a halide or halogen-alcoholate of Ti and optionally an electron-donor compound supported on anhydrous magnesium chloride.
• Catalysts having the above-mentioned characteristics and polymerization processes employing such catalysts are well known in the patent literature; particularly advantageous are the catalysts and polymerization processes described in USP 4,399,054 and EP-A-45 977. Other examples can be found in USP 4,472,524.
• the catalysts can be pre-contacted with small amounts of olefins (prepolymerization).
• Mineral fillers (D) present in the composition of the present invention include talc, CaC0 3 , silica, mica, wollastonite (CaSi0 3 ), clays, diatomaceaous earth, titanium oxide and zeolites. Talc is preferred. Typically the mineral filler is in particle form having an average diameter ranging form 0.1 to 5 micrometers.
• nucleating agents (F) include, for example, metal salts of carboxylic acids, dibenzylsorbitol derivatives, alkali metal salts of phosphate and the like.
• specific examples of the nucleating agents include sodium benzoate, aluminum adipate, aluminum p-t-butylbenzoate, 1,3,2,4-dibenzylidenesorbitol, l,3,2,4-bis(p-methyl- benzylidene)sorbitol, 1 ,3,2,4-bis(p-ethylbenzylidene)sorbitol, 1 ,3-p-chlorobenzylidene-2,4-p- methylbenzylidene)sorbitol, sodium bis(4-t-butylphenyl) phosphate, sodium bis(4-t- methylphenyl) phosphate, potassium bis(4,6-di-t-butylphenyl) phosphate, sodium 2,2'- methylene-bis(4,6-
• composition of the present invention can also contain additives commonly employed in the art, such as antioxidants, light stabilizers, heat stabilizers and colorants.
• composition of the present invention can be prepared by melt-blending the components (A), (B), (C), (D) and optionally (E) and/or (F) or by melt-blending the matsterbatch composition (I) with the other polyolefm components, and with the component
• any mixing apparatus equipped with mixing elements and known in the art can be used, such as an internal mixer or extruder.
• an internal mixer or extruder For example one can use a Banbury mixer or single-screw Buss extruder or twin-screw Maris or Werner type extruder.
• the present invention also provides final articles, in particular door trims, made of the said polyolefm composition.
• condition L i.e. 230°C with 2.16 kg load
• Notched IZOD impact test ISO 180/1 A.
• Gloss 10 rectangular specimens (55x60x1 mm) for each polymer to be tested are prepared by injection molding using an injection press Battenfeld BA500CD operated under the following conditions:
• the value of the injection pressure should be sufficient to completely fill the mould in the above mentioned indicated time span.
• the glossmeter used is a photometer Zehntner model ZGM 1020 or 1022 set with an incident angle of 60°.
• the measurement principle is given in the Norm ASTM D2457.
• the apparatus calibration is done with a sample having a known gloss value.
• the percent by weight of polymer insoluble in xylene at room temperature is considered the crystallisable portion of the polymer. This value also corresponds substantially to the isotacticity index determined by extraction with boiling n-heptane, which by definition constitutes the isotacticity index of polypropylene. Longitudinal and transversal thermal shrinkage
• a plaque of 100 x 200 x 2.5 mm is moulded in an injection moulding machine
• the injection conditions are:
• melt temperature 250°C
• the plaque is measured 48 hours after moulding, through callipers, and the shrinkage is given by:
• 200 is the length (in mm) of the plaque along the flow direction, measured immediately after moulding
• 100 is the length (in mm) of the plaque crosswise the flow direction, measured immediately after moulding;
• the read_value is the plaque length in the relevant direction.
• the instrument used is a PerkinElmer Diamond DSC.
• the polymer sample is heated to 230°C at a rate of 10°C/min and kept at 230°C for 5 minutes in nitrogen stream and it is thereafter cooled at a rate of 10°C/min to 20°C, thereby kept at this temperature for 5 min to crystallise the sample. Then, the sample is again fused at a temperature rise rate of 10°C/min up to 230°C.
• the melting scan is recorded, a thermogram is obtained, and, from this, the temperature and fusion enthalpy value corresponding to the most intense peak between 100 and 130°C are read.
• the solid catalyst component used in polymerization is a highly stereospecific Ziegler-Natta catalyst component supported on magnesium chloride, prepared according to the Example 5, lines 48-55 of the European Patent EP728769.
• Triethylaluminium (TEAL) is used as co-catalyst and dicyclopentyldimethoxysilane (DCPMS) as external donor.
• the solid catalyst component is contacted at 12° C for 24 minutes with TEAL and DCPMS.
• the weight ratio between TEAL and the solid catalyst component and the weight ratio between TEAL and DCPMS are of 20 and 10 respectively.
• the catalyst system is then subjected to prepolymerization by maintaining it in suspension in liquid propylene at 20° C for about 5 minutes before introducing it into the first polymerization reactor.
• the polymerisation run is conducted in continuous in a series of two reactors equipped with devices to transfer the product from one reactor to the one immediately next to it.
• the first reactor is a liquid phase reactor
• the second reactor is a fluid bed gas phase reactor.
• Component (A 1 ) is prepared in the first reactor, while component (B 1 ) is prepared in the second reactor, respectively.
• Component (A 1 ) is a propylene homopolymer, while component (B 1 ) is an ethylene/butene-1 copolymer.
• Hydrogen is used as molecular weight regulator.
• the gas phase (propylene, ethylene, butene and hydrogen) is continuously analysed via gas- chromatography.
• the polymer particles exiting the second reactor are subjected to a steam treatment to remove the reactive monomers and volatile substances, and then dried.
• the polymer particles are introduced in a rotating drum, where they are mixed with 0.05% by weight of paraffin oil ROL/OB 30 (having a density of 0.842 kg/1 at 20 °C according to ASTM D 1298 and flowing point of -10 °C according to ASTM D 97), 0.15% by weight of Irganox® B 215 (made of about 34% Irganox® 1010 and 66% Irgafos® 168) and 0.04% by weight of DHT-4A (hydrotalcite).
• paraffin oil ROL/OB 30 having a density of 0.842 kg/1 at 20 °C according to ASTM D 1298 and flowing point of -10 °C according to ASTM D 97
• Irganox® B 215 made of about 34% Irganox® 1010 and 66% Irgafos® 168
• DHT-4A hydrotalcite
• the said Irganox 1010 is 2,2-bis[3-[,5-bis(l,l-dimethylethyl)-4-hydroxyphenyl)-l- oxopropoxy]methyl]-l,3-propanediyl-3,5-bis(l,l-dimethylethyl)-4-hydroxybenzene- propanoate, while Irgafos 168 is tris(2,4-di-tert.-butylphenyl)phosphite.
• the polymer particles are extruded under nitrogen in a screw extruder with a melt temperature of 200-250 °C.
• the characteristics relating to the polymer compositions, reported in Table II, are obtained from measurements carried out on the so extruded polymer.
• the masterbatch compositions 1 to 3 prepared as described above, are mechanically mixed with the other components by extrusion under the previously described conditions.
• the proportions of the polyolefm components used in these examples are reported in Table III, together with the amounts of components A), B), C) and E) of the final composition, obtained by aggregating the contributions of said polyolefm components, and with the calculated value of MFR L of A), based on the previously reported correlation of MFR logarithms.
• PP Propylene homopolymer having a MFRL value of 2000 g/10 min. and solubility in xylene at room temperature of 2.3% by weight;
• ENR7467 Engage ENR 7467 as described above;
• Heco Polyolefm composition (heterophasic blend) comprising 67% by weight of propylene homopolymer having a MFRL value of 9 g/10 min. and solubility in xylene at room temperature of 2% by weight, and 33% by weight of ethylene/propylene copolymer containing 38% by weight of ethylene and having a solubility in xylene at room temperature of 84% by weight and an intrinsic viscosity of the xylene soluble fraction of 7.5 dl/g.
• EG8407 and ENR7467 together constitute the component C) of the composition of the present invention.
• talc and a nucleating agent are added.
• the talc D) used is Neotalc UNI manufactured by Neotalc Industries, Ltd .
• the amount of D) is reported in Table III as well.
• Sodium-2,2'-methylene-bis(4,6-di-t-butylphenyl)-phosphate (trade name NA11, manufactured by Asahi Denka K. K.) is used as nucleating agent F).
• the amount of F) in the compositions of all the examples is 0.1 parts by weight with respect to 100 parts by weight of A) + B) + C) + D) + E).
• Table III and Table IV are reported the data of a composition obtained by blending the same components as in Examples 1 and 2, but using a masterbatch composition identified as Comparison 1, having MFRL of 15 g/10 min. and comprising (percentages by weight):
• B 1 26% of a copolymer of ethylene and butene-1, containing 21% of butene-1 and having solubility in xylene at room temperature of 51%, the intrinsic viscosity of the xylene soluble fraction being of 1.2 dl/g.

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