CA1331239C - Thermoplastic olefin polymer and method of preparing same - Google Patents

Abstract

Abstract of Disclosure Disclosed is a thermoplastic olefin polymer having elastic properties, comprising:
a) greater than 60 to 85 parts of a crystalline polymer fraction (i) a copolymer over 85 wt. % of propylene and at least one alpha-olefin H2C=CHR (where R is H or C2-6 alkyl) having an isotacticity index of greater than 75, (ii) a polybutene-1 having an isotacticity index of greater than 75, (iii) an ethylene homopolymer having a density of 0.95 g/cm3 or greater, or ethylene/alpha-olefin copolymer having a density of 0.94 g/cm3 or greater or (iv) polymer fraction (i), (ii) or (iii) in combination with, or mixtures thereof alone or in combination with, from 10 to 90 parts, based on the thermoplastic olefin polymer, of a homopolymer of propylene having an isotacticity index of greater than 85, b) 1 to less than 15 parts of a semi-crystalline, low density, essentially linear copolymer fraction of units of a alpha-olefin H2C=CHR is insoluble in xylene at room temperature; and c) 10 to less than 39 parts of an amorphous copolymer fraction of 30-80 weight % of an alpha-olefin H2C=CHR and propylene, with or without a diene or a different alpha-olefin termonomer, soluble in xylene at room temperature. The thermoplastic olefin polymers are produced by sequential polymerization using certain catalysts supported on an activated magnesium dihalide.

Description

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1 331 23q This invention relates to thermoplastic olefin polymers having elastic properties, and to a method for preparing same. More particularly this invention relates to thermoplastic olefin polymers which have an e~cellent S balance of several properties, such as flexibility, tensile strength, impact strength, tear strength and elongation.
Thermoplastic olefin polymers prepared by physically blending or mixing monoolefin copolymer or terpolymer rubbers and polyolefins are known (see, e.g. U.S.
3,03h,987, 3,835,201 and U.S. 4,748,206?. However, in order to achieve a good dispersion of the rubber in the polyolefin it is necessary to employ enargy intensive mi~ing.
The formation of thermoplastic elastomers (TPE) from such blends is also known. Although there are a number of methods taught, the one generally practiced is dynamic vulcanization of such bl~nds, such as by the method described in U.S. 3,806,558.
In order to avoid the disadvantages iassociated with physical blending while at the same time avoid the necessity to dynamically vulcanize such blends, efforts have been made to produce reactor or chemical blends of a crystalline polypropylene and an amorphous ethylene-;~ propylene copolymer rubber by sequential polymerization in a reactor.
In U.S. 4,489,195, for e~ample, the preparation ofpolyolefin thermoplastic elastomers by a two-stage ~ ~ r " 1331239 polymerization process using stereospecific catalysts composed of an organoaluminum compound and a solid catalyst component on a magnesium halide support is taught. In the first stage 5-50 wt. % of a homopolymer of propylene is S formed, and in the second, 50-95% of an ethylene-propylene copolymer having a propylene content of 5-60% is prepared by adding ethylene monomer which reacts with the unreacted propylene monomer of the first stage. The polypropylene produced in the first stage and the ethylene-propylene rubber of the second stage are believed to be chemically combined so as to form a block copolymer. One of the disadvantages of this method is that the temperature in the second stage must be kept relatively low, i.e. not more than 50C, in order to prevent agglomeration of the ethylene-copolymer rubber particles and reactor fouling.
This need to operate the second stage at relatively low temperatures penalizes the process with respect to heat e~change and diminishes catalyst mileage.
U.S. 4,491,652 also describes the preparation of polypropylene thermoplastic elastomers in two stages. In the first stage the propylene is polymerized to a homopolymer polypropylene. In the second stage, ethylene is added and ethylene and propylene are polymerized in the presence of a solvent, preferably at temperatures of 60-77C, to form rubbery copolymers and block copolymers of the polypropylene and ethylene/propylene rubbery copolymer. The polymerizations conditions employed in the second stage leads to the formation of a partially soluble rubbery copolymer which tends to cause the resultant product to lump or agglomerate. These lumps or agglomerates must be broken up to provide a homogeneous product. Typically this is done by grinding on a mill. As a matter of fact, it is known that when over 20%, based on the thermoplastic elastomer, of the rubbery ethylene/
propylene copolymer is produced during the preparation of ` 1 33 1 239 . ~
the thermoplastic elastomer, it is impossible to avoid 3 agglomeration of the particles even when the polymerization takes place in the presenca of stereospecific catalysts (see, e.~., European application 0029651 and U.S.
4,259,461).
Polymerization of such rubbery copolymers in a gas processr even in small amounts of 20~ or more, likewise leads to product agglomeration and fouling of the ¦ reactors. This reactor fouling effectively prevents one 10 from conducting such a polymerization process in gas phase.
rhere~ore~ it is necessary to be able to produce a thermoplastic olefin polymer having the desired balance of mechanical properties in a reactor or sequence of reactors, including, where desirable, at least one gas phase reactor, 15 which avoids the disadvantages associated with the present methods of producing this type of polymer.
The present invention provides a thermoplastic olefin polymer comprising a) greater than 60 to about 85 parts of a crystalline polymer fraction selected from the group consisting of (i) a copolymer of propylene and at least one alpha-olefin having the formula H2C~CHR, where R is H or a C2 6 straight or branched chain alkyl, containing over 85% by weight of propylene and having an isotacticity inde~ of greater than 75, (ii) a polybutene-l having an isotacticity index of greater than 75, (iii) an ethylene homopolymer having a density of 0.95 g/cm3 or greater, or a copolymer of . ethylene with a C3 8 alpha-olefin having a density of 0.94 g/cm or greater, (iv) polymer fraction (i), , (ii) or (iii) in combination with, or mixtures thereof alone or in combination with, from 10 to 90 parts, based on the thermoplastic olefin polymer, of a homopolymer of propylene having an isotacticity index of greater than 85~

b) from about 1 up to less than 15 parts of a semi-crystalline, low density, essentially linear copolymer fraction consisting substantially of units of the alpha-olefin used to prepare c) or the alpha-olefin used to prepare c) which is present in the greatest amount when two alpha-olefins are used, which polymer is insoluble in xylene a~ room temperature; and c) from about 10 to less than 39 parts of an amorphous copolymer fraction of an alpha-olefin having ;
the above formula and propylene, with or without 1 to 10~ of a diene or 1 to 20~ of a different alpha-olefin termonomer having the above formula, which copolymer contains from about 30 to about 80 weight ~ alpha-olefin, e~cluding the alpha-olefin present, if any, as a termonomer, and is soluble in ~ylene at room temperature, having a fle~ural modulus lower than 1000 MPa to 150 MPa, tensile strength greater than 7 MPa, impact strength such 20 that it breaks with a ductile impact failure at -18C and an elongation at break over 200~i, wherein the total of components a), b) and c) is 100 parts.
This invention further provides a method of producing such thermoplastic olefin polymers by sequential 25 polymerization in at least two stages in a reactor or two -or more reactors, one or more of which may be gas phase reactor, using certain catalysts supported on an activated m magnesium dichloride.
Unless otherwise indicated, all parts and percentages 30 set forth herein are by weight.
Component a) is preferably present in an amount from 65 to about 75 parts.
Component a) (i) is typically a copolymer of propylene and at least one alpha-olefin having the formula set forth _4_ 133123q herein above, such as propylene/ethylene, propylene/
butene-l and propylene/4-methyl-pentene-1, or a terpolymer of propylene and two different alpha-o~efins, such as propylene/ethylene/butene-l, propylene/butene-1~4-methyl-pentene-l and propylene/ethylene/4-methylpentene-1.
The crystalline propylene copolymer of component a) , (i) preferably contains from 90 to 98 wt. % propylene, most preferably from 95 to 98 wt. % propylene.
The preferred isotacticity inde~ of component a) (i) and (ii) is greater than ~5 with the most preferred being greater than 90.
Typically when component a) (iii) is a copolymer of ethylene with a C3 8 alpha-olefin, the alpha-olefin is present in an amount from about 1 to 10%. Suitable ethylene copolymers useful as component a) (iii) include ethylene/butene-l, ethylene/hexene-l and ethylene/4-methyl-l-pentene.
Preferably component a) is a propylene/ethylene copolymer, propylene/butene-l copolymer or propylene/
eth~lene/butene-l terpolymer.
When component a) (i), (ii) or (iii) or mixtures thereof are combined witb a homopolymer of propylene, it is preferably present in an amount from 30 to 70 parts, most preferably 40 to 60 parts.
Component b) is preferably present in an amount from about 3 to less than 15, most preferably from about 5 to less than 10.
Component c) is preferably present in an amount from about 10 to less than 30, most preferably from about 20 to less than 30.
The alpha-olefin in the copolymer of component c) is preferably present in an amount from about 40 to about 75 wt. ~. ~hen component c) is a terpolymer, the alpha-olefin employed as a termonomer is preferably present in an amount from about 3 to about 10 wt. %.

Typical dienes useful in the preparation of component c) are 1,4-hexadiene, 1,5-hexadiene, dicyclopentadiene, ethylidene norbornene, l,6-octadiene and vinyl norbornene.
Ethylidene norbornene is preferred.
Component c) is preferably an amorphous ethylene/pro-pylene copolymer, ethylene/propylene~diene monomer terpolymer or ethylene/propylene~butene-l terpolymer.
Suitable alpha-olefins useful in the preparation of the various components of the thermoplastic olefin polymers of this invention include ethylene, butene-l, pentene-1, 4-methylpentene-1, hexene-l and octene-l. Ethylene and butene-l are preferred.
The resultant thermoplastic olefin polymer has a high bulk density and is in the form of free flowing spherical particles having an average diameter from 250 and 7000 microns, preferably from 500 to 7000 microns. Hence, post-polymerization granulation or grinding is not required before the polymer can be further processed, converted or fabricated. The flowability of the polymer particles at 70C is lower than 30 seconds and the bulk density (compacted) is greater than 0.4 g/cc, preferably greater than 0.4 to about 0.6 g/cc.
The total content of the polymerized alpha-olefin in the thermoplastic olefin polymer of this invention, excluding the alpha-olefin present, if any, as a termonomer when component c) is a terpolymer, is from 10 to 30, preferably from 15 and 25% by weight.
The molecular weight of the various components (determined by measuring intrinsic viscosity in tetrahydronaphthalene at 135C) varies depending on the nature of the components and the melt index of the final product. Generally it is within the following preferred limits: preferably from 0.5 to about 3 dl/g for component a) and from 1 to about 3 dl/g for components b) and c).

The thermoplastic olefin polymers of the present invention have one major melting peak determined by DSC at higher than 115C, preferably higher than 135C, most preferably higher than 140C; fla~ural modulus lower than 1000 MPa to 150 MPa, preferably from 150 to 700 MPa, most preferably from 500 to 700 MPa; elongation at break over 200%, preferably over 500%; tensile at break greater than 7 MPa, preferably greater than 10 MPa, most preferably greater than 13 MPa; and an impact strength such that it preferably breaks with a ductile impact failure at -29~C.
The polymers of this invention can be used to manufacture parts, components and materials useful in the automotive industry, such as automotive interior trim and bumpers, and in the industrial consumer market, including the medical, furniture, appliance, building/construction and recreational/sports industries.
The compositions are prepared by a polymerization process includinq at least two stages. In the first stage the relevant monomers or monomers are polymerized to form component a), and in the following stages the relevant monomers are polymerized to form components b) and c).
The polymerization reactions can be done in liquid or gas phase processes, or in a combination of liquid and gas phase processes using separate reactors, all of which can be done either by batch or continuously.
The preferred method of preparing the thermoplastic olefin polymer of this invention is a two stage process comprising the polymerization of component a) in liquid phase in the presence of a liquid monomer, and the polymerization of component b) and c) in gas phase.
The polymerization reactions are carried out in an inert atmosphere in the presence of an inert hydrocarbon solvent or of a liquid or gaseous monomer.
Hydrogen can be added as needed as a chain transfer agent for control of the molecular weight.

1 33 1 23~
The typical reàction temperature used in the polymerization of component a) and in the polymerization of components b) and c) ma~ be the same or diferent~
Generally the reaction temperature employed for the polymeri~ation of component a) is from about 40C to about 90OC, preferably from about 50C to about 80C. Components b) and c) are typically polymerized at a temperature from about 50C to about 80C, preferably about 65C to 80OC.
The reactions can be conducted at a pressure from about atmospheric to about 1000 psi, preferably from about 150 to 600 psi in liquid phase polymerization and from atmospheric to 30 atmospheres, preerably from 5 to 30 atmospheres, in gas phase polymerization. Typical residence times are from about 30 minutes to about 8 hours.
Suitable inert hydrocarbons solvents include saturated hydrocarbons such as propane, butane, he~ane and heptane.
The catalyst system used in the polymerization comprises the reaction product of 1) a solid catalyst component containing a titanium compound and an electron-donor compound supported on activated magnesium dichloride, 2) a trialkylaluminum compound as activator and 3) an electron-donor compound.
Suitable titanium compound include those with at least one Ti-halogen bond, such as halides and halogen alcoholates of titanium.
In order to obtain the thermoplastic olefin polymers of this invention in the form of flowable spherical particles having a high bulk density, it is essential that the solid catalyst component have a) a surface area smaller than 100 m2/g, preferably between 50 and 80 m2/g, b) a , porosity from 0.25 to 0.4 cc/g. and c) an X-ray spectrum, where the magnesium chloride refections appear, by the presence of a halo between the angles 2 ~5~of 33.5 and 35 and by the absence of the reflection at 2 ~ of 14.95.
The symbol ~ ~ Bragg angle.

.

1 33 1 23q The solid catalyst component is prepared by orming an adduct of magnesium dichloride and an alcohol, such as ethanol, propanol, butanol and 2-ethylhexanol, containing generally 3 moles of alcohol per mole of MgC12, S emulsiEying the adduct, cooling the emulsion quickly to cause the adduct to solidify into spherical particles, and partially dealcoholating th~ particulate adduct by gradually increasing the temperature from 50C to 100C for a period of time sufficient to reduce the alcohol content from 3 moles to 1-1.5 moles per mole of MgC12. The partially dealcoholated adduct is then suspended TiC14 at OoC, such that the concentration of adduct to TiC14 is 40-50 9~1 TiC14. The mixture is then heated to a temperature of 80C to 135C for a period of about 1-2 hr.
lS When the temperature reaches 40C, sufficient electron donor is added so that the molar ratio of Mg to electron donor is 8. When the heat treatment period has ended, the e~cess hot TiC14 is separated by filtration or sedimentation, and the treatment with TiClq is repeated one or more times. The solid is then washed with a suitable inert hydrocarbon compound and dried.
The solid catalyst component typically has the following characteristics:
surface area: less than 100 m2/g, preferably between 50 and 80 m2/g porosity: 0.25 - 0.4 cc/g pore volume distribution: 50% of the pores have a radius greater than 100 angstroms.
X-ray spectrum: where the Mg chloride refections appear, showing a halo with maximum intensity between angles of 2 ~ of 33.5 and 3S, and where the reflection at 2 1~'of 14.95 is absent. I-_g _ ` ` 1 33 1 239 Suitable electron-donor compounds for use in preparing the solid catalyst component include alkyl, cycloalkyl or aryl phthalates, such as diisobutylphthalate, di-n-butylphthalate and di-n-octylphthalate.
~le~ane and heptane are typical hydrocarbon compounds used to wash the solid catalyst component.
The catalyst is obtained by mi~ing the solid catalyst component with a trialkyl aluminum compound, preferably triethyl aluminum and triisobutyl aluminum, and an 1~ electron-donor compound.
Various electron donor compunds are known in the art.
The preferred electron donor compounds are those silane compounds having the formula R'R''Si~OR)z where R' and R"
may be the same or different and are alkyl, cycloalkyl, or 1-18 carbon aryl radicals, and R is a 1-4 carbon alkyl radical.
Typical silane compounds which may be used include diphenyldimetho~ysilane, dicyclohe~yldimetho2ysilane, methyl-t-butyldimethoxysilane, diisopropyldimethoxysilane and phenyltrimethoxysilane.
The Al/Ti ratio is typically between 10 and 200 and the Al/silane ratio between 2 and 100, preferably 5 and 50.
The catalysts may be precontacted with small quantities of olefin monomer (prepolymerization), maintaining the catalyst in suspension in a hydrocarbon solvent and polymerizing at a temperature from room temperature to 60C for a time suf f icient to produce a quantity of polymer from 0.5 to 3 times the weight of the catalyst.
This prepolymerization also can be done in liquid or gaseous monomer to produce, in this case, a quantity of polymer up to 1000 times the catalyst weight.
The content and amount of catalyst residue in the thermoplastic olefin polymers of this invention is ' " I 33 1 23q sufficiently small so as to make the removal of catalyst residue, typically referred to as deashing, unnecessary.
Unless otherwise specified, the following analytical methods were used to characterize the supported catalyst component, the thermoplastic olefin polymer samples of this invention and comparative samples.

Proeertie$ MethQd Melt Flow Inde~, g/10 min. ASTM-D 1238 Ethylene, wt % Spectroscopy I.R.
10 Intrinsic viscosity Determined in tetrahydro-- naphthalene at 135C
Xylene solubles, wt % See description below.
Fle~ural modulus ASTM-D 790 Notched IZOD impact ASTM-D 256 VICAT (1 ~g) softening pt. ASTM-D 1525 Tensile Strength ASTM-D 638 ~ Elongation at break ASTM-D 633 ; Surface area B. E. T.
Porosity B. E. T.
20 Bulk density DIN-53194 Fluidity The time that it takes 100 g of polymer to f low through a funnel with an output opening of 1.27 cm and walls inclined at an angle of 20~ with respect to the vertical.
Granulometry ASTM-D 1921-63 The physical tests are conducted on pelletized samples ,---of this invention, which were stabilized with 500 ppm of 30 calcium stearate, 500 ppm of paraffinic oil, 350 ppm of tetrakis(2,4-di-t-butylphenyl) 9,4'-biphenylylenediphos-phonite, 500 ppm tetrakis[methylene(3,5-di-t-butyl-4-hydro~yhydrocinnamate~ methane and 250 ppm octadecyl 3,5-di-t-but~1-4-hydro~yhydrocinnamate. The samples were molded using a Negri & ~ossi 90 injection press with a melt ~emperature of 190C, a mold temperature of 60C, an injection time 20 seconds and a cooling time of 25 seconds.
S The percent by weight of components b) and c) is calculated by determining the weight of the propylene and alpha-olefin (and diene or different alpha-olefin termonomer if used) misture used in the second stage and comparing it to the weight of the final product.
The weight percent of component a) is determined by subtracting the weight percents of component b) and c) from 100 .
The weight percent of component c) is determined by subtracting.the weight fraction of component a) soluble in xylene multiplied by the weight percent of component a) from the weight percent of the final product soluble in xylene.
The weight percent of component b) is determined by subtracting ~he weight percent of component a) and of component c) from 100.
The percent by weight of the alpha-olefin contained in the copolymer of component c) which is soluble in xylene is calculated using the following formula:

CF ~ C . Q
Alpha-olefin wt. ~ in component c) ~
y where CF is the wt. % of alpha-olefin in the soluble of xylene in the final product; Cw is the wt. % alpha-olefin in the soluble in xylene of component a); Q is the wt. %
soluble in ~ylene of component a) multiplied by the weight , 30 fraction of component a) and divided by the wt. fraction of the final product soluble in xylene; and Y is the wt. % of component c) multiplied by the sum of the wt. % of component b) and component c) and then divided by one hundred.

~`l `.~`
l~ ~

The weight percent of soluble in xylene at room temperature is determined by dissolving 2.5 9 of the pol~mer in 250 ml of xylene in a vessel equipped with a stirrer which is heated at 135C with agitation for 20 minutes. The solution is cooled to 25C while continuing the agitation, and then let to stand without agitation for 30 minutes so that the solids can settle. The solids are filtered with ~ilter paper, the remaining solution is evaporated by treating it with a nitrogen stream, and the solid residue is vacuum dried at 80OC until a constant weight is reached.
The percent by weight of polymer insoluble in xylene at room temperature is the isotactic index of the polymer. The value obtained in this manner corresponds substantially to - the isotactic inde~ determined via extraction with boiling n-heptane, which by definition constitutes the isotactic inde~ of the polymer.
Examples illustrative of the thermoplastic olefin polymer o this invention, the physical properties thereof and the method of preparing same are set forth ~elow.
~; 20 A) Preparation of MgC12/Alcohol Adduct Under an inert atmosphere, 28.4 g anhydrous MgC12, 49.5 9 of an anhydrous ethanol, 100 ml of ROL O~/30 vaseline oil~ 100 ml of silicone oil having a viscosity of 350 cs are introduced into a reaction vessel equipped with a stirrer and heated at 120C with an oil bath and stirred until the Mg~12 is dissolved. The hot reaction mi~ture was then transferred under inert atmosphere to a 1500 ml vessel equipped with an Ultra Turra ~ -45 N stirrer and a heating jacket and containing 150 ml of vaseline oil and 150 ml of silicone oil. The temperature was maintained at 120C with stirring for 3 minutes at 3,000 rpm. The mixture was then discharged into a 2 liter vessel equipped with a stirrer containing 1,000 ml of anhydrous n-heptane cooled at 0C
with a dry ice/isopar bath and stirred at a rip speed of 6 r~ ~-n~k -13-m~sec for about 20 minutes while maintaining the temperature at 0C~ The adduct particles thus formed were recovered by filtering, were washed 3 times at room temperature with 500 ml aliquots of anhydrous he~ane and gradually heated by increasing the temperature from 50C to 100C under nitrogen ~or a period of time sufficient to reduce the alcohol content from 3 moles to 1.5 moles per mole of MgC12. The adduct had a surface area of 9.1 m /g and a bulk density of 0.564 g/cc.
B) Solid Catalyst Component Preparation The adduct (25 g) was transferred under nitrogen into a reaction vessel aquipped with a stirrer and containing 625 ml of TiC14 at 0C under agitation. It was then heated to 100C in 1 hr. When the temperature reached 40C, diisobutylphthalate was added in an amount such that the molar ratio of Mg to diisobutylphthalate is 8. The contents of the vessel were heated at 100C for 2 hours with agitation, the agitation was stopped and the solids were allowed to settle. The hot liquid was removed ~y siphon.
550 ml of TiC14 was added to the solids in the ~essel and ; the mi~ture heated at 120C for 1 hr. with agitation. The - agitation was stopped and the solids were allowed to settle. The hot liquid was then removed by siphon. The - solids were washed 6 Limes at 60C with 200 ml aliquots of anhydrous hexane, and then 3 times at room temperature. The solids, after be~ng vacuum dried, had a porosity of 0.261 cc~g, a surface area of 66.5 m2/g and a bulk density of 0.44 g~cc.
E~amples 1-4 These examples illustrate the thermoplastic olefin ~' polymers of this invention and a method for preparing the - polymers.
The preparations for polymerization and the polymerization runs were conducted under nitrogen in a series of reactors with a means for transferring the product produced in the immediately preceding reactor to the next reactor. A11 temperatures, pressures and concentrations of olefin monomers and hydrogen, when present, were constant S unless otherwise indicated. The hydrogen is analyzed continuously in gas phase and fed in order to maintain constant the desired concentration of hydrogen.
In the following e~amples a mi~ture of TEAL activator and dicyclohexyldimetho~ysilane electron donor in an amount such that the weight ratio of TEAL:silane was about 4.0 in e~amples 1, 2 and 3 and about 4.8 in e~ample 4, was contacted with an amount of the solid catalyst component, as described above, such thàt the molar ratio of TEAL:Ti was 191, 132, l~q and 142 in e~amples 1, 2, 3 and 4, respectively, in a reactor at 15C for about 15 minutes.
The catalyst was then transferred to another reactor containing an e~cess of liquid propylene and polymerized for 3 minutes at 20OC.
In the first stage, the prepolymer was transferred to 20 another reactor for a liquid phase polymerization of the '~
relevant monomer(s) to form a component a). The component ~; a) thus formed was then transferred to another reactor in e~amples 1, 3 and 4 for a liquid phase polymerization of the relevant monomer(s) to increase the amount of component a) formed in the first polymerization reactor or to prepare a different component a), and to a second stage reactor in the ~ case of example 2 as described below.
; In the second stage, the component a) product of the immediately preceding reactor was first transferred into a flash pipe and any unreacted monomers were degassed at essentially atmospheric pressure and then fed to another reactor for a gas phase polymerization of the relevant monomers to form components b) and c). The resultant product was then transferred to another reactor for an additional gas phase polymerization of the relevant monomers in order to increase the amount of components b) and c) in the product.
At the end of the second staqe polymerization reaction the powder is discharged into a steaming apparatus and the unreacted monomers and volatiles are removed by treating with steam at 105C at atmospheric pressure for about 10 minutes and then dried.
The ingredients and relative operating conditions are set forth in Table lA and the tests results are set forth in Table lB.

``` 1 3~ 1 239 Table lA

_____________________________________________________________ E~amples 1 2 3 4 _____________________________________________________________ FIRST PHASE
First reactor S Temperature, C 65 65 60 60 Pressure, atm 33 33 33 33 Time, min. 56 52 50 71 H2 in gas phase, ppm 18002400 3100 1400 C2 in gas phase, g/hr ` 24003500 2066 3800 - 10 C3 in liquid phase, 490540 550 500 Kg/hr Isotactic index, % wt. - 92 Ethylene, % wt - 1.9 Ethylene in sol.xyl., - 7.9 % wt Second Reactor : Temperature, C 54 - 60 70 . Pressure, atm 33 - 33 33 Time, min. 39 - 39 49 ~:~ 20 H2 in gas phase, ppm 1850 - 2896 6500 C2 in gas phase, g~hr 750 - 633 C3 in liquid phase, 190 - 150 195 Kg/hr Isotactic index, ~ wt. 91.5 - 91 92.5 : Z5 Ethylene, % wt2.2 - 2.0 1.6 Ethylene in sol.xyl., 8.4 - 8.1 7.5 ~ wt : -17-Table lA (Cont'd) _____________________________________________________________ E~amples 1 2 3 4 _____________________________________________________________ SECO~D PH~SE
Third Reactor Temperature, C 75 75 75 75 Pressure, atm 19 14. 14 14 Time, min. 22 24 22 19 H2 in gas phase,6.3 7.2 6.2 8.0 % moles C2 in gas phase,40.6 39.2 41 36 % moles C3 in gas phase,46 45.5 g8.5 45 % moles Fourth Reactor Temperature, C 75 75 75 75 Pressure, atm 11 11 11 10.7 Time, min. 27 29 26 23 H2 in gas phase,6.2 7.3 6.2 7.0 % moles C2 in gas phase,40 39.3 41 39.5 % moles C3 in gas phase,48 46.2 .49 47 % moles _ _ _ _ :::
, : -18-133123~
Table lB
_____________________________________________________________ E~amples 1 2 3 _____________________________________________________________ FINAL PRODUCT
~ield, Kg pol/g cat19.3 12.2 17.5 16.5 Component b~ & c),30.0 25.0 29.0 38.0 % wt Ethylene, ~ wt 21.0 19.3 22.9 25.3 Intrinsic ~iscosity,1.86 - 1.60 dl~g Melt flow inde~, 10~0 16.0 20.0 11.0 g/10 min ~ylene sol., % wt25.5 2q.2 25.6 28.2 Component b), % wt7.0 6.8 9.8 14.9 Component c), % wt23.0 18.2 19.2 23.6 C2 in sol.xyl., ss.o 53.7 50.7 4B.8 % wt C2 in component c),64.9 68.8 64.8 57.0 ~: % wt Melting point (DSC), C 151 152 152 154 ~: ` 20 Fle~ural modulus, MPa 560 640 570560 : IZOD impact,-20C, J/m115 80 75 129 Impact failure at -18C ductile ductile ductile ductile Vicat (1 kg), C 118122 - 115 ~; Elong. at break, %~500~500 ~500 >500 Tensile strength, MPa 19.0 17.3 15.5 16.5 _________________________ -19_ `

Physical blends of a) a propylene homopolymer with (i) an ethylene-propylene rubber or (ii) an ethylene-propylene d;ene monomer rubber and b) a propylene-ethylene copolymer with (ii) were prepared by mixing the two materials in a ~anbury mixer at a temperature of approx. 205C until a homogeneous blend was obtain. Such blends are commercially available.
The formulations and the physical properties are set forth in Table II below.

TABLE II

Comparative Examples Ingredients 1 2 3 Propylene homopolymerl 60 60 Propylene-ethylene copolymer2 - - 60 15 Ethylene propylene rubber3 40 Ethylene propylene diene monomer (EPDM)4 - 40 40 Octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate 0.1 0.1 0.1 20 MFR, dg/min 7.3 3.0 3.2 Tensile strength, MPa 15.3 13.013.5 Elongation, % 429 443 618 Flexural modulus, MPa 670 700 445 1 MFR of 12 dg~min.
25 2 Random copolymer having a MFR of 12 dg/min and approx. 2.5% ethylene.
3 77% ethylene, polydispersity 2.8, Mooney Viscosity, 54 (ML 1~4 at 125C).
4 51% ethylene, 2.2% ethylidene norbornene, polydispersity 3.8, Mooney Viscosity, 46 (ML 1+4 at 125C).

`` 1 33 1 239 Given the lower melt flow of the commercially available physical blends set forth in Table II, which typically translates into better physical properties, one would not have e~pected the thermoplastic olefin polymers of this invention with their higher melt flow rates to have such superior tensile strength, elongation and ductile impact properties when compared on an essentially equivalent stiffness (flexural modulus) basis.
Other features, advantages and embodiments of the invantion disclosed herein will be readily apparent to those e~ercising ordinary skill after reading the foregoing disclosures. In this regard, while speci~ic embodiments of the invention have been describied in considerable detail, variations and modifications of these embodiments can be e~fected without departing from the spirit and scope of the invention as described and claimed.

Claims (27)

1. A thermoplastic olefin polymer comprising:
a) greater than 60 to about 85 parts of a crystalline polymer fraction selected from the group consisting of (i) a copolymer of propylene and at least one alpha-olefin having the formula H2C=CHR, where R is H or a C2-6 straight or branched chain alkyl, containing over 85% by weight of propylene and having an isotacticity index of greater than 75, (ii) a polybutene-1 having an isotacticity index of greater than 75, (iii) an ethylene homopolymer having a density of 0.95 g/cm3 or greater, or a copolymer of ethylene with a C3-8 alpha-olefin having a density of 0.94 g/cm3 or greater, (iv) polymer fraction (i), (ii) or (iii) in combination with, or mixtures thereof alone or in combination with, from 10 to 90 parts, based on the thermoplastic olefin polymer, of a homopolymer of propylene having an isotacticity index of greater than 85, b) from about 1 up to less than 15 parts of a semi-crystalline, low density, essentially linear copolymer fraction consisting substantially of units of the alpha-olefin used to prepare c) or the alpha-olefin used to prepare c) which is present in the greatest amount when two alpha-olefins are used, which polymer is insoluble in xylene at room temperature; and c) from about 10 to less than 39 parts of an amorphous copolymer fraction of an alpha-olefin having the above formula and propylene, with or without 1 to 10% of a diene or 1 to 20% of a different alpha-olefin termonomer having the above formula, which copolymer contains from about 30 to about 80 weight %
alpha-olefin, excluding the alpha-olefin present, if any, as a termonomer, and is soluble in xylene at room temperature, having a flexural modulus lower than 1000 MPa to 150 MPa, tensile strength greater than 7 MPa, impact strength such that it breaks with a ductile impact failure at -18°C and an elongation at break over 200%, wherein the total of compo nents a), b) and c) is 100 parts.

2. The polymer of claim 1 wherein component a) is (i).

3. The polymer of claim 1 wherein component a) is (ii).

4. The polymer of claim 1 wherein component a) is (iii).

5. The polymer of claim 2 wherein (i) is a copolymer of propylene and ethylene.

6. The polymer of claim 2 wherein (i) has an isotacticity index of greater than 90.

7. The polymer of claim 3 wherein (ii) has an isotacticity index of greater than 85.

8. The polymer of claim 4 wherein (iii) is a copolymer of ethylene with 1 to 10% of the alpha-olefin.

9. The polymer of claim 4 wherein (iii) is a copolymer of ethylene and butene-1.

10. The polymer of claim 4 wherein (iii) is a homopolymer of ethylene.

11. The polymer of claim 1 wherein component a) is (i) in combination with from 10 to 90 parts, based on the thermoplastic olefin polymer, of a homopolymer of propylene having an isotacticity index of greater than 85.

12. The polymer of claim 1 wherein the flexural modulus is from 150 to 700 MPa, the tensile strength is greater than 10 MPa, the elongation at break is greater than 500%, and the impact strength is such that it preferably breaks with a ductile impact failure at -29°C.

13. The polymer of claim 1 wherein the flexural modulus is from 500 to 700 MPa, the tensile strength is greater than 13 MPa, and the elongation at break is greater than 500%.

14. The polymer of claim 1 wherein the polymer is in the form of spherical particles having an average diameter of 250 to 7000 microns, a flowability of less than 30 seconds and a bulk density (compacted) greater than 0.4 g/cc.

15. The polymer of claim 2 wherein the flexural modulus is from 150 to 700 MPa, the tensile strength is greater than 10 MPa, the elongation at break is greater than 500%, and the impact strength is such that it preferably breaks with a ductile impact failure at -29°C.

16. The polymer of claim 2 wherein the flexural modulus is from 500 to 700 MPa, the tensile strength is greater than 13 MPa, and the elongation at break is greater than 500%.

17. The polymer of claim 2 wherein the polymer is in the form of spherical particles having an average diameter of 250 to 7000 microns, a flowability of less than 30 seconds and a bulk density (compacted) greater than 0.4 g/cc.

18. A process for the preparation of the thermoplastic olefin polymer of claim 1 comprising at least two sequential polymerization stages with each subsequent polymerization being conducted in the presence of the polymeric material formed in the immediately preceding polymerization reaction wherein component a) is prepared in at least one first stage, and components b) and c) are prepared in at least one second stage, all polymerization stages using a catalyst comprising a trialkylaluminum compound, an electron donor and a solid catalyst component comprising a halide or halogen-alcoholate of Ti and an electron-donor compound supported on anhydrous magnesium chloride, said component having a surface area smaller than 100 m2/g, a porosity from about 0.2 to 0.4 cc/g, a pore volume distribution such that over 50% of the pores have a radius greater than 100 angstroms, and having an X-ray spectrum, where the magnesium chloride reflections appear, showing a halo with maximum intensity between angles of 2 ? of 33.5° and 35°, and where the reflection at 2 of 14.95° is absent.

19. The process of claim 18 wherein the polymeriza-tion of component a) is carried out in liquid monomer, and the polymerization of component b) and c) are carried out in gas phase.

20. The process of claim 18 wherein the polymerizations are carried out in gas phase.

21. A thermoplastic olefin polymer having elastic properties in the form of free flowing spherical particles having an average diameter of 250 to 7,000 microns, comprising:
a) greater than 60 to 85 parts of a crystalline polymer fraction selected from the group consisting of:
(i) a copolymer of over 85% by weight of propylene and at least one alpha-olefin of the formula H2C=CHR (where R
is H or a C2-6 straight or branched chain alkyl) having an isotacticity index of greater than 75, (ii) a polybutene-1 having an isotacticity index of greater than 75, and (iii) an ethylene homopolymer having a density of 0.95 g/cm3 or greater or a copolymer of ethylene and 1 to 10%
by weight of one C3-8 alpha-olefin having a density of 0.94 g/cm3 or greater;
b) 1 to less than 15 parts of a semi-crystalline, low density, essentially linear copolymer fraction consisting essentially of units of one alpha-olefin of the formula H2C=CHR
(where R is as defined above), insoluble in xylene at room temperature; and c) 10 to less than 39 parts of an amorphous copolymer fraction of propylene and 30 to 80% by weight of one alpha-olefin of the formula H2C=CHR (where R is as defined above) with or without 1 to 10% by weight of a diene or 1 to 20% of one different alpha-olefin termonomer of the formula H2C=CHR, soluble in xylene at room temperature, wherein the thermoplastic copolymer has a flexural modulus lower than 1000 MPa to 150 MPa, a tensile strength greater than 7 MPa, such an impact strength that it breaks with a ductile impact failure at -18°C and an elongation at break over 200%; the total of components a), b) and c) is 100 parts;

and the total content of the alpha-olefin of the formula H2C=CHR excluding the alpha-olefin termonomer in component c) is 10 to 30% by weight.

22. The polymer of claim 21, wherein the alpha-olefin of the formula H2C=CHR is ethylene.

23. The polymer of claim 21, wherein the alpha-olefin of the formula H2C=CHR is butene-1.

24. The polymer of claim 21, wherein the crystalline polymer fraction a) is the copolymer (i).

25. The polymer of claim 21, wherein the crystalline polymer fraction a) is the polybutene-1 (ii).

26. The polymer of claim 21, wherein the crystalline polymer fraction a) is the ethylene polymer (iii).

27. A shaped article formed by molding the polymer as defined in any one of claims 1 to 17 or any one of claims 21 to 26.