Propylene polymers with improved properties

Abstract

The invention relates to novel propylene polymers with improved properties especially with improved stiffness and impact strength comprising propylene homopolymers or propylene block copolymers with 90.0 to 99.9 wt % propylene and 0.1 to 10 wt % α-olefins with 2 or 4 to 18 carbon atoms, or mixtures thereof, wherein the propylene homopolymers or propylene block copolymers are β-nucleated propylene polymers, whereby the β-nucleated propylene homopolymers have an IRτ≧0.98, a tensile modulus ≧1500 MPa at +23° C. and a Charpy impact strength, ≧3 kJ/m 2 at −20° C. using notched test specimens, and the β-nucleated propylene block copolymers are polymers having an IRτ of the propylene homopolymer block of ≧0.98, a tensile modulus ≧1100 Mpa at +23° C. and a Charpy impact strength of ≧6 kJ/m 2 at −20° C. using notched test specimens. The propylene polymers with an improved property spectrum are suitable for producing molded parts in a pipe system, such as pipes and fittings, inspection chambers, pipe ducting systems, extrusion or compression molded sheets and the like.

1 ) Propylene polymers with improved properties comprising propylene homopolymers with melt indices of 0.05 to 15 g/10 min at 230° C./2.16 kg or propylene block copolymers with 90.0 to 99.9 wt % propylene and 0.1 to 10 wt % α-olefins with 2 or 4 to 18 carbon atoms with melt indices of 0.05 to 20 g/10 min at 230° C./2.16 kg, or mixtures thereof, wherein the propylene homopolymers or propylene block copolymers are D-nucleated propylene polymers, whereby the β-nucleated propylene homopolymers have an IRτ ≧0.98, a tensile modulus of ≧1500 MPa at +23° C. and a Charpy impact strength of ≧3 kJ/m 2  at −20° C. using notched test specimens, and the β-nucleated propylene block copolymers are polymers having an IRτ of the propylene homopolymer block of ≧0.98, a tensile modulus of ≧1100 MPa at +23° C. and a Charpy impact strength, of ≧6 kJ/m 2  at −20° C. using notched test specimens.  
     
     
         2 ) Propylene polymers according to  claim 1  comprising propylene homopolymers with melt indices of 0.1-8 g/10 min at 230° C./2.16 kg or propylene block copolymers with 90.0 to 99.9 wt % propylene and 0.1 to 10 wt % α-olefins with 2 or 4 to 18 carbon atoms with melt indices of 0.1 to 8 g/10 min at 230° C./2.16 kg, or mixtures thereof, wherein the propylene homopolymers or propylene block copolymers are β-nucleated propylene polymers, whereby the β-nucleated propylene homopolymers have an IRτ ≧0.98, a tensile modulus of ≧1600 MPa at +23° C. and a Charpy impact strength of 4 to 10 kJ/m 2  at −20° C. using notched test specimens, and the β-nucleated propylene block copolymers are polymers having an IRτ of the propylene homopolymer block of ≧0.98, a tensile modulus of ≧1300 MPa at +23° C. and a Charpy impact strength, of ≧9 kJ/m 2  at −20° C. using notched test specimens.  
     
     
         3 ) Propylene polymers according to one of the claims  1  or  2 , wherein the 1-nucleated propylene homopolymers with an IRτ ≧0.98 or propylene block copolymers with an IRτ ≧0.98 in the homopolymer block are propylene polymers obtained by polymerization with a Ziegler-Natta catalyst system comprising titanium-containing solid components, an organoalumina, magnesium or titanium compound as cocatalyst and an external donor according to the formula  
       R x R′ y Si(MeO) 4-x-y ,  
       wherein R and R′ are identical or different and are branched or cyclic aliphatic or aromatic hydrocarbon residues, and y and x independently from each other are 0 or 1, provided that x+y are 1 or 2.  
     
     
         4 ) Propylene polymers according to  claim 3 , characterized in that the external donor is dicyclopentyldimethoxysilane.  
     
     
         5 ) Propylene polymers according to one of the  claims 1  to  4 , wherein the β-nucleated propylene polymer contains 0.01 to 2.0 wt %, in each case based on the propylene polymers used, of 
 dicarboxylic acid derivative type diamide compounds from C 5 -C 8 -cycloalkyl monoamines or C 6 -C 12 -aromatic monoamines and C 5 -C 8 -aliphatic, C 5 -C 8 -cycloaliphatic or C 6 -C 12 -aromatic dicarboxylic acids, preferably N,N′-di-C 5 -C 8 -cycloalkyl-2,6-naphthalene dicarboxamide compounds, N,N′-di-C 5 -C 8 -cycloalkyl-4,4-biphenyldicarboxamide compounds, N,N′-di-C 5 -C 8 -cycloalkylterephthalamide compounds, N,N′-di-C 5 -C 8 -cycloalkyl-1,4-cyclohexanedicarbox-amide compounds and/or N,N′-di-C 6 -C 12 -aryl-C 5 -C 8 -diamide compounds; and/or  
 diamine derivative type diamide compounds from C 5 -C 8 -cycloalkyl monocarboxylic acids or C 6 -C 12 -aromatic monocarboxylic acids and C 5 -C 8 -cycloaliphatic or C 6 -C 12 -aromatic diamines, preferably N,N′-C 6 -C 12 -arylene-bis-benzamide compounds, N,N′-C 5 -C 8 -cycloalkyl-bis-benzamide compounds, N,N′-p-C 6 -C 12 -arylene-bis-C 5 -C 8 -cycloalkylcarboxamide compounds and/or N,N′-C 5 -C 8 -cycloalkyl-bis-cyclohexanecarboxamide compounds; and/or  
 amino acid derivative type diamide compounds from amidation reaction of C 5 -C 8 -alkyl-, C 5 -C 8 -cycloalkyl- or C 6 -C 12 -arylamino acids, C 5 -C 8 -alkyl-, C 5 -C 8 -cycloalkyl- or C 6 -C 12 -aromatic monocarboxylic acid chlorides and C 5 -C 8 -alkyl-, C 5 -C 8 -cycloalkyl- or C 6 -C 12 -aromatic mono-amines, preferably N-phenyl-5-(N-benzoylamino)pentaneamide and/or N-cyclohexyl-4-N-cyclohexylcarbonylamino) benzamide, as β-nucleating agent.  
 
     
     
         6 ) Propylene polymers according to one of the  claims 1  to  4 , characterized in that the β-nucleated propylene polymer contains 0.0001 to 2.0 wt % quinacridone type compounds, preferably quinacridone, dimethylquinacridone and/or dimethoxyquinacridone; quinacridonequinone type compounds, preferably quinacridonequinone, a mixed crystal of 5,12-dihydro(2,3b)acridine-7,14-dione with quino(2,3b)acridine-6,7,13,14-(5H,12H)-tetrone and/or dimethoxyquinacridonequinone; and/or dihydroquinacridone type compounds, preferably dihydroquinacridone, dimethoxydihydroquinacridone and/or dibenzodihydroquinacridone, as β-nucleating agent.  
     
     
         7 ) Propylene polymers according to one of the  claims 1  to  4 , characterized in that the β-nucleated propylene polymer contains 0.01 to 2.0 wt % dicarboxylic acid salts of metals from group IIa of periodic system, preferably pimelic acid calcium salt and/or suberic acid calcium salt; and/or mixtures of dicarboxylic acids and metals from group IIa of periodic system, as β-nucleating agent.  
     
     
         8 ) Propylene polymers according to one of the  claims 1  to  4 , characterized in that the β-nucleated propylene polymer contains 0.01 to 2.0 wt % of salts of metals from group IIa of periodic system and imido acids of the formula  
       
         
           
           
               
               
           
         
       
       wherein x=1 to 4; R═H, —COOH, C 1 -C 12 -alkyl, C 5 -C 8 -cycloalkyl or C 6 -C 12 -aryl, and Y═C 1 -C 12 -alkyl, C 5 -C 8 -cycloalkyl or C 6 -C 12 -aryl-substituted bivalent C 6 -C 12 -aromatic residues, preferably calcium salts of phthaloylglycine, hexahydrophthaloylglycine, N-phthaloylalanine and/or N-4-methylphthaloylglycine, as β-nucleating agent.  
     
     
         9 ) A process for producing propylene polymers with improved properties from propylene homopolymers with melt indices of 0.05 to 15 g/10 min at 230° C./2.16 kg and/or block copolymers from 90.0 to 99.9 wt % of propylene and 0.1 to 10 wt % of α-olefins with 2 or 4 to 18 carbon atoms with melt indices of 0.05 to 20 g/10 min at 230° C./2.16 kg, wherein β-nucleated propylene homopolymers have an IRτ ≧0.98, a tensile modulus ≧1500 MPa and a Charpy impact strength of ≧3 kJ/m 2  at −20° C., using notched test specimens, respectively β-nucleated propylene block copolymers having an IRτ of the propylene homopolymer block of ≧0.98, a tensile modulus ≧1100 MPa and a Charpy impact strength ≧6 kJ/m 2 , at −20° C., using notched test specimens, are produced by melt mixing of propylene homopolymers having an IRτ ≧0.98, respectively propylene block copolymers having an IRτ of the propylene homopolymer block of ≧0.98, with 0.0001 to 2.0 wt %, based on the polypropylenes used, of β-nucleating agents at temperatures from 175 to 250° C.  
     
     
         10 ) Use of the propylene polymers with improved properties according to one of the  claims 1  to  8  as well as of mixtures with conventional propylene homopolymers and/or propylene copolymers for producing molded parts in a pipe system, such as pipes and fittings, inspection chambers, pipe ducting systems, extrusion or compression molded sheets and the like.  
     
     
         11 ) Use of propylene homopolymers with melt indices of 0.05 to 15 g/10 min at 230° C./2.16 kg which propylene homopolymers are β-nucleated, where the β-nucleated propylene homopolymers have an IRτ ≧0.98, for producing articles with a tensile modulus of ≧1500 MPa at +23° C. and a Charpy impact strength of ≧3 kJ/m 2  at −20° C. using notched test specimens.  
     
     
         12 ) Use of propylene block copolymers with 90.0 to 99.9 wt % propylene and 0.1 to 10 wt % α-olefins with 2 or 4 to 18 carbon atoms with melt indices of 0.05 to 20 g/10 min at 230° C./2.16 kg which propylene block copolymers are β-nucleated, where the β-nucleated propylene block copolymers have an IRτ of the propylene homopolymer block of ≧0.98, for producing articles with a tensile modulus of ≧1100 MPa at +23° C. and a Charpy impact strength, of 6 kJ/m 2  at −20° C. using notched test specimens.