Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/04—Monomers containing three or four carbon atoms
  • C08F210/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/06—Hydrocarbons
  • C08F212/12—Monomers containing a branched unsaturated aliphatic radical or a ring substituted by an alkyl radical
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F218/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
  • C08F218/02—Esters of monocarboxylic acids
  • C08F218/04—Vinyl esters
  • C08F218/08—Vinyl acetate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/14—Methyl esters, e.g. methyl (meth)acrylate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/42—Nitriles
  • C08F220/44—Acrylonitrile
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F255/00—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
  • C08F255/02—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00 on to polymers of olefins having two or three carbon atoms

Definitions

• the present invention relates to random copolymers of propylene as main recurring units comprising recurring units deriving from styrene.
• the present invention also relates to functionalized copolymers and graft copolymers.
• the invention moreover, relates to processes for the production of said copolymers.
• the present invention lies in the technical field of the production of thermoplastic materials.
• plastic materials based on isotactic polypropylene are among the most interesting ones from the technology viewpoint. In fact, they are not only competitive from a cost perspective, but are also suitable for various applications due to suitable chemical and physical modifications.
• the chemical modification mostly used in the industry is the random copolymerisation of propylene with small amounts of one or more comonomer(s), generally ethylene or butene-1. Said modification allows to obtain materials that have a lower melting temperature (above all used for producing films with thermoweldable layers), lower stiffness, higher impact resistance at low temperatures and a higher transparency than the isotactic propylene homopolymer.
• ethylene and butene-1 recurring units have a sterical hindrance similar enough to propylene recurring units. Consequently, although they cause a decrease in packing energy, they are partially enclosed as defects in the crystalline phase. As it is well known, generally speaking, in semicrystalline polymeric materials one obtains a more efficient decrease in crystallinity and size of crystallites when one uses comonomer units with much higher hindrance than the basic monomer units, i.e. such that they have inevitably to be excluded from the crystalline phase.
• EP-A-872 492 discloses catalytic systems based on stereorigid metallocenes that contain a metallic atom belonging to the IV group of the Periodic Table and whose substituted cyclopentadienyl groups are bridged through a single atom. Said metallocenes are capable of copolymerising olefins with vinyl aromatic compounds. As disclosed in the patent application, such catalyst systems, however, produce copolymers containing blocks of styrene units. This is, for instance, shown by the Nuclear Magnetic Resonance spectrum of Figure 29, therein.
• the copolymers of the instant invention essentially show no variation of the glass transition temperature compared with isotactic polypropylene.
• the glass transition temperature compared with isotactic polypropylene is observed, e.g. if T is measured by Differential Scansion Calorimetry at a rate of 10° K per minute, its value does not exceed 0° C.
• 1/T g W prop /'T x g prop + W " st Jr ⁇ g styr
• W prop and W styr are respectively propylene and styrene fractions by weight
• T g prop and T g styr are respectively the glass transition temperatures of polypropylene and polystyrene homopolymers.
• the glass transition temperatures of the styrene polymers are much higher than that of polypropylene and the molecular mass of the styrenic units is much larger than that of the propylene unit, a substantial increase of the glass transition temperature should be observed also in cases of a low content by mole of the styrenic units and this would make said materials unusable in applications which demand a low running temperature.
• some of the copolymers of the present invention can be used for preparing functionalized polypropylene as well as graft copolymers.
• the present invention provides, therefore, new isotactic-polypropylene-based copolymers having a homogenous distribution of recurring units of the formula (1):
• R is a hydrogen, halide radical or a hydrocarbyl radical optionally containing an atom selected from oxygen, nitrogen, sulphur, phosphorus and silicon and n is an integer ranging from 1 to 3.
• copolymers of the present invention contain the recurring units of formula (1) preferably in amounts ranging from 0.1 to 30% by weight.
• Said copolymers have a 13 C-NMR spectrum wherein the resonance signals attributable to the links between different monomeric units fall around 30, 34, 35, 45 and 47 ppm and present intensities at least 2 times higher than the resonance signals attributable to styrene-styrene sequences around 41 ppm and 44-46 ppm (all chemical shifts are relative to tetramethylsilane).
• R of formula (1) is hydrogen, that is for styrene- ethene comonomer units
• the resonance signals attributable to the links between different monomeric units fall at 30.3, 33.9, 34.6, 44.8, 46.9 ppm.
• the polymerisation degree of the copolymers of the present invention is normally at least 50.
• R When R is a substituent containing carbon atoms, it can be selected from C,-C 20 alkyl radicals, linear or branched, C 3 -C 20 cycloalkyl radicals and C 6 -C 20 aryl radicals.
• the alkyl radicals may be saturated or unsaturated radicals.
• the preferred radicals are metyl, ethyl, isopropyl, vinyl and allyl radicals.
• Said substituent R may contain a functional group, such as -NR 2 , where R is an alkyl group as above defined.
• sequences of propylene recurring units are mainly isotactic.
• content of meso diads (m) is higher than 80%.
• the amount of the structural units of formula (1) in the copolymer may be determined on the basis of the intensity of specific signals in the ⁇ C nuclear magnetic resonance spectra.
• the presence of said structural units is put in evidence by signals in the aliphatic region at 33.9 and 25.2 ppm (chemical shift from tetramethylsilane, TMS) and the molar fraction of the styrenic units (X s ), equal to the molar fraction of the connected ethylenic units, can be obtained by the following relation:
• A is the intensity of the signal at x ppm.
• the copolymers of the invention have a homogeneous distribution of the comonomers. Such homogeneity is also proved by the impossibility by solvent extraction to obtain fractions of the copolymers with a X s value differing more than 50% from the X s value of the unfractionated sample.
• the copolymers of the instant invention can be obtained according to the known polymerisation methods.
• the copolymers can be produced by means of the homogeneous catalytic systems used for the insertion polymerization of propylene which give an isotactic homopolymer, e. g. catalytic systems based on metallocene compounds.
• Suitable examples of said metallocene compounds are r ⁇ c-ethylene-bis(l-indenyl)-ZrCl 2 , r ⁇ c-isopropylidene-bis(l-indenyl)-ZrCl 2 , r ⁇ c-dimethylsilyl-bis(l-indenyl)-ZrCl 2 , r ⁇ c-dimethylsilyl-bis(2-methyl-l-indenyl)-ZrCl 2 , r ⁇ c- dimethylsilyl-bis(2-methyl-4-isopropyl- 1 -indenyl)-ZrCl 2 , r ⁇ c-dimethylsilyl-bis(2-methyl-4- phenyl-l-indenyl)-ZrCl 2 , r ⁇ c-dimethylsilyl-bis(2-methyl-benz[e]-l -indenyl)-ZrCl 2 , rac- dimethylsilyl-bis(benz[
• Suitable activating cocatalyst according to the process of the invention are alumoxanes or compounds capable of forming an alkyl metallocene cation.
• Alumoxane useful as cocatalyst may be linear alumoxanes of formula (2):
• R' is selected from the group consisting of halogen, linear or branched, saturated or unsaturated C,-C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl and C 7 -C 20 arylalkyl radicals and y ranges from 0 to 40; or cyclic alumoxanes of formula (3):
• R 1 has the meaning herein described and y is an integer ranging from 2 to 40.
• alumoxanes may be obtained according to procedures known in the state of the art, by reacting water with an organo-aluminum compound of formula A1R' 3 or A1 2 R' 6 , with the condition that at least one R' is not halogen-
• the molar ratios of Al/water in the reaction are comprised between 1 :1 and 100: 1.
• organometallic aluminum compounds of formula (II) described in EP 0 575 875 and those of formula (II) described in WO 96/02580.
• suitable cocatalysts are those described in WO 99/21899 and in the European patent app. no. 99203110.4.
• the molar ratio between aluminum and the metal of the metallocene is comprised between about 10:1 and about 5000:1, and preferably between about 100: 1 and about 4000:1.
• alumoxanes suitable as activating cocatalysts in the process of the invention are methylalumoxane (MAO), tetra-isobutyl-alumoxane (TIBAO), tetra-2,4,4- trimethylpentylalumoxane (TIOAO) and tetra-2-methyl-pentylalumoxane. Mixtures of different alumoxanes can also be used.
• aluminum compounds of formula AIR 8 , or A1 2 R 8 6 are: tris(methyl)aluminum, tris(isobutyl)aluminum, tris(isooctyl)aluminum, bis(isobutyl)aluminum hydride, methyl-bis(isobutyl)aluminum, dimethyl(isobutyl)aluminum, tris(isohexyl)aluminum, ris(benzyl)aluminum, tris(tolyl)aluminum, tris(2,4,4-trimethylpentyl)aluminum, bis(2,4,4-trimethylpentyl)aluminum hydride, isobutyl-bis(2-phenyl-propyl)aluminum, diisobutyl-(2-phenyl-propyl)aluminum, isobutyl-bis(2,4,4-trimethyl-pentyl)aluminum, is
• Particularly preferred aluminum compounds are trimethylaluminum (TMA), tris(2,4,4-trimethylpentyl) aluminum (TIOA), triisobutylaluminum (TIBA), tris(2,3,3- trimethyl-butyl)aluminum and tris(2,3-dimethyl-butyl)aluminum.
• both said metallocene and said alumoxane can be pre-reacted with an organometallic aluminum compound of formula A1R' 3 or A1 2 R' 6 , wherein R 1 has the meaning reported above.
• organometallic aluminum compound of formula A1R' 3 or A1 2 R' 6 wherein R 1 has the meaning reported above.
• Further activating cocatalysts suitable in the catalysts of the invention are those compounds capable of forming an alkylmetallocene cation. Examples are boron compounds tetrakis-pentafluorophenyl-borate is particularly preferred.
• compounds of formula BAr 3 can be conveniently used.
• the catalysts of the present invention can also be used on an inert support, by depositing the metallocene, or the reaction product of the metallocene with the cocatalyst, or the cocatalyst and successively the metallocene, on the inert support, such as silica, alumina, magnesium halides, olefin polymers or prepolymers (i.e. polyethylenes, polypropylenes or styrene-divinylbenzene copolymers).
• the thus obtained supported catalyst system optionally in the presence of alkylaluminum compounds, either untreated or pre-reacted with water, can be usefully employed in gas-phase polymerization processes.
• the solid compound so obtained, in combination with further addition of the alkyl aluminum compound as such or prereacted with water, is usefully employed in gas phase polymerization.
• the molecular weight of the polymers can be varied by changing the polymerization temperature or the type or the concentration of the catalyst components, or by using molecular weight regulators, such as hydrogen, as well-known in the state of the art.
• the polymerization process according to the present invention can be carried out in gaseous phase or in liquid phase, optionally in the presence of an inert hydrocarbon solvent either aromatic (such as toluene), or aliphatic (such as propane, hexane, heptane, isobutane and cyclohexane).
• an inert hydrocarbon solvent either aromatic (such as toluene), or aliphatic (such as propane, hexane, heptane, isobutane and cyclohexane).
• the polymerization temperature ranges from about 0° to about 250° C, preferably from 20° to 150° C, and more preferably from 40° to 90° C.
• the molecular weight distribution can be varied by using mixtures of different metallocenes or by carrying out the polymerization in various steps differing in the polymerization temperature and/or in the concentration of the polymerization monomers.
• the polymerization yield depends on the purity of metallocenes in the catalyst; the metallocene according to the present invention may be used as such or may be previously subjected to purification treatments.
• the metallocene and cocatalyst may be suitably contacted among them before the polymerization.
• the contact time may be comprised between 1 and 60 minutes, preferably between 5 and 20 minutes.
• the pre-contact concentrations for the metallocene are comprised between 10 "2 and 10 s mol/1, whereas for the cocatalyst they are comprised between 10 and 10 "3 mol/1.
• the precontact is generally carried out in the presence of a hydrocarbon solvent and, optionally, of small amounts of monomer.
• the copolymerization of propylene and styrene is carried out in the presence of small amounts of ethylene.
• propylene concentration may be between 0J M and 13 M
• styrene concentration between 10 "3 M and 9 M
• ethylene concentration less than one tenth of the propylene concentration catalyst concentration between 10 "8 M and 10 "2 M.
• the polymerisation temperature is between -30° C and +150° C, preferably between 0° C and 100° C.
• copolymers of the present invention can be blended with other polymers, preferably with isotactic propylene polymers.
• Such polymer blends can be prepared by a mechanical blend of the polymers, at least at the soft temperature, preferably at the melting temperature, of the polymers.
• the blend can be carried out by way of a polymerisation that can be carried out in at least two sequential steps, wherein the polymers are prepared in separate subsequent steps, operating in each steps, except in the first step, in the presence of the polymer formed in the preceding step.
• the catalyst can be the same in all the steps or different. For instance, a Ziegler-Natta catalyst can be used in the first step, while said homogeneous catalyst systems can be used in the subsequent step(s).
• the present invention also provides functionalized copolymers.
• the copolymers of the present invention are particularly useful for producing functionalized copolymers, which are technologically important to improve their adhesion to and compatibility with other materials.
• the comonomeric units of formula (1) can be functionalized under various free radical, anionic and cationic processes, as described in the open and patent literature for random copolymers between ethene and styrene or substituted styrenes.
• benzylic protons can be oxidated, halogenated or metallated, to form desirable functional groups (COOH, CH 2 X , and CH 2 Mt, respectively) bonded to the phenyl rings.
• benzylic protons can be interconverted to stable anionic initiators for graft polymerizations.
• the metallated polymer (mainly lithiated) can be suspended in an inert organic diluent before addition of monomers, such as styrene, substituted styrenes, vinyl acetate, methylacrylate, methylmethacrylate, acrylonitrile. This procedure can be particularly relevant for the preparation of graft copolymers presenting polystyrene branches onto isotactic polypropylene backbones.
• Another object of the present invention is the graft copolymers comprising isotactic- polypropylene-based copolymers as backbones.
• graft copolymers of the present invention are polystyrene or polyvinylacetate or polymethacrylate or polymethylmethacrylate or polyacrylonitrile grafted onto isotactic polypropylene.
• Said graft copolymers may be obtained by the above-mentioned method.
• graft copolymers are mainly useful as compatibilizers in the preparation of normally incompatible polymer blends or alloys.
• polymers to be blended with the propylene polymers in the presence of the graft copolymers are polystyrene, polyether, polyacrylate, such as polymethylacrylate.
• the reaction is started by injecting in the flask 3 mg of r ⁇ c-ethylene-bis(l-indenyl) ZrCl 2 catalyst dissolved in 2 mL of anhydrous toluene.
• the produced polymer is coagulated in 200 mL of ethanol acidified with HC1, filtered and dried in a vacuum oven.
• the yield is of about 120 mg.
• Fig. IB shows that the resonance signal at about 41 ppm, which are attributable to the styrene-styrene sequences, is nearly 6 times less intense than the resonance signal at 30.3 ppm and nearly 3 times less intense than the resonance signals at 33.9, 34.6, 44.8, 46.9 ppm, all attributable to the links between different monomeric units. This fact confirms the statistical nature of the obtained product.
• the weight average molecular mass measured by gel permeation chromatography is of 3 x 10 3 u.m.a. Comparative Example 1
• a propylene-styrene polymerization is carried out with a catalyst system of the same kind as those described in the previously cited Arai et al. patent.
• the reaction is started by injecting in the flask 5 mg of r ⁇ c-isopropylidene-bis(l- indenyl) ZrCl 2 catalyst dissolved in 2 mL of anhydrous toluene.
• the produced polymer is coagulated in 200 mL of ethanol acidified with HC1, filtered and dried in a vacuum oven.
• the yield is of about 320 mg.
• Fig. 2B shows that the resonance signals at about 41 and 43 ppm, which are attributable to the styrene-styrene sequences, have intensities comparable to those of the resonance signals attributable to the links between different monomeric units, falling in the region from 30 to 38 ppm, notwithstanding the fact that the content of styrene units is lower than in the product of Example 1 (8% vs. 12%). This fact indicates the presence of blocks in the polymer.
• the catalyst system employed, the operating method and the reaction conditions are identical with those of Example 1, except for the amounts of styrene (10 mL) and toluene (20 mL) employed.
• the yield is of about 200 mg.
• the reaction is carried out at 0° C in a 250 mL autoclave containing 50 mL of toluene, 3.2 ml of styrene, 0.9 g of MAO and 9 mg of the same catalyst employed in Examples 1 and 2, by feeding a gaseous mixture of ethylene/propylene (1/4 mol/mol) at 2 atmospheres.
• the reaction is started by injecting in the flask 6 mg of r ⁇ c-ethylene-bis(l-indenyl) ZrCl 2 catalyst dissolved in 2 mL of anhydrous toluene.
• the produced polymer is coagulated in 200 mL of ethanol acidified with HC1, filtered and dried in a vacuum oven.
• the yield is of about 500 mg.
• the polymer results to consist essentially of isotactic polypropylene and to contain 0.7% by moles of p-methyl-styrene units and 0.9% by moles of ethylene units (of which 0.7% are associated with the p-methyl-styrene units, X s - 0.07).
• the catalyst system employed, the operating method and the reaction conditions are identical with those of Example 4, except for the fact that divinyl benzene is used instead of p-methyl-styrene and the composition of the propylene/ethylene mixture is 75/1 mol/mol.
• the yield is of about 500 mg.

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• 1999
  • 1999-02-11 IT IT1999SA000005A patent/ITSA990005A1/it unknown
• 2000
  • 2000-02-10 BR BR0004772-4A patent/BR0004772A/pt not_active IP Right Cessation
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