Polyolefin multilayer pipe

Abstract

Polyolefin multilayer pipes consisting at least one of the layers of a β-nucleated propylene homopolymer and/or β-nucleated copolymers from 90.0 to 99.9% by weight of propylene and 0.1 to 10.0% by weight of α-olefins. The pipes are to be classified in ring stiffness class ≧4. The pipes are suitable for non pressure pipe applications, preferably for outdoor use, for above as well as underground drainage and sewerage pipe systems, surface water pipes, pipes for cable protection, pipes for cold climate conditions and for indoor use, soil and waste water pipes.

1 ) polyolefin multilayer pipes where at least one of the layers of the multilayer pipe comprises a propylene homopolymer with melt indices of 0.05 to 10 g/10 min at 230° C./2.16 kg or a propylene block copolymer from 90.0 to 99.9% by weight of propylene and 0.1 to 10.0% by weight of α-olefins with 2 or 4 to 18 carbon atoms with melt indices of 0.05 to 15 g/10 min at 230° C./2.16 kg, or mixtures thereof, wherein the propylene homopolymer and/or propylene block copolymer are β-nucleated propylene polymers and where the β-nucleated propylene homopolymer has an IR τ ≧0.98, a tensile modulus of ≧1500 MPa at +23° C. and a Charpy impact strength, using notched test specimens, at −20° C. ≧3 kj/m 2  and where the β-nucleated propylene block copolymer has an IR τ  of the propylene homopolymer block of ≧0.98, a tensile modulus of ≧1100 MPa at +23° C. and a Charpy impact strength ≧6 kJ/m 2  at −20° C. using notched test specimens and the multilayer pipe with a pipe diameter of less than 0.25 m has an impact energy E D  (normalised) of at least 400 Nm/m and a ring stiffness S determined according to ISO 9969≧4 kN/m and a multilayer pipe a pipe diameter of ≧0.25 m has impact energy E of at least 120 nm and a ring stiffness S determined according to ISO 9969≧4 kN/m 2 .  
     
     
         2 ) Polyolefin multilayer pipes according to  claim 1  wherein the multilayer pipe with a pipe diameter of less than 0.25 m has an impact energy E D  (normalised) of at least 600 Nm/m and a ring stiffness S determined according to ISO 9969 ≧4 kN/m 2  and a multilayer pipe with a pipe diameter of ≧25 m has impact energy E of at least 180 Nm and a ring stiffness S determined according to ISO 9969 ≧4 kN/m 2 .  
     
     
         3 ) Polyolefin multilayer pipe according to one of the claims  1  or  2 , wherein the β-nucleated propylene polymers with an IR τ ≧0.98 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 ) Polyolefin multilayer pipe according to  claim 3 , wherein the external donor is dicyclopentyldimethoxysilane.  
     
     
         5 ) Polyolefin multilayer pipe according to one of  claims 1  to  4 , wherein the β-nucleated propylene polymer contains 0.0001 to 2.0 wt %, based on the polypropylenes used, 
 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 - 8 -cycloaliphatic or C 6 -C 12 -aromatic dicarboxylic acids, and/or  
 diamine derivative type diamide compounds from C 5 -C 8 -cycloalkyl monocarboxylic acids or C 8 -C 12 -aromatic monocarboxylic acids and C 5 - 8 -cycloaliphatic or C 6 -C 12 -aromatic diamines, and/or  
 amino acid derivative type diamide compounds from amidation reaction of C 5 -C 8 -alkyl-, C 5 - 8 -cycloalkyl- or C 5 - 12 -arylamino acids, C 5 - 8 -alkyl-C 5 - 8 -cycloalkyl- or C 5 - 12 -aromatic monocarboxylic acid chlorides and C 5 - 8 -alkyl-, C 5 -C 8 -cycloalkyl- or C 6 -C 12 -aromatic mono-amines, and/or  
 quinacridone derivative compounds of the type quinacridone compounds, quinacridonequinone compounds, and/or dihydroquinacridone type compounds, and/or  
 dicarboxylic acid salts of metals from group IIa of periodic system and/or mixtures of dicarboxylic acids and metals from group IIa of periodic system, and/or  
 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 - 8 -cycloalkyl or C 6 -C 12 -aryl, and Y=C 5 - 12 -alkyl, C 5 - 8 -cycloalkyl or C 6 - 12 -aryl-substituted bivalent C 8 - 12 -aromatic residues, as β-nucleating agent.    
 
     
     
         6 ) Polyolefin multilayer pipe according to one of  claims 1  to  5 , wherein the multilayer pipe is a 3-layer pipe, wherein the outer and inner layer of the pipe comprises a β-nucleated propylene polymer and the mid layer comprises a recycled propylene polymer, a propylene polymer of higher stiffness than the β-nucleated propylene polymer, a propylene polymer containing fillers.  
     
     
         7 ) Polyolefin multilayer pipe according to one of  claims 1  to  6 , wherein the multilayer pipe is a 2-layer pipe, wherein the outer layer of the pipe comprises a β-nucleated propylene polymer and the inner layer comprises a recycled propylene polymer, a propylene polymer of higher stiffness than the β-nucleated propylene polymer, a propylene polymer containing fillers.  
     
     
         8 ) Polyolefin multilayer pipe according to one of the claims  1  or  7 , characterized in that the multilayer pipe is a smooth pipe with or without hollow sections.  
     
     
         9 ) Polyolefin pipe according to one of the claims  1  or  8 , characterized in that the multilayer pipe is a corrugated or ribbed pipe with or without hollow sections.  
     
     
         10 ) A process for producing polyolefin multilayer pipes by extrusion or injection molding processes where at least one of the layers of the multilayer pipe comprises a propylene homopolymer with melt index of 0.05 to 10 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 10.0 wt % of α-olefins with 2 or 4 to 18 carbon atoms with melt indexes of 0.1 to 15 g/10 min at 230° C./2.16 kg, wherein the propylene homopolymers and/or propylene block copolymers are β-nucleated propylene polymers and wherein the propylene homopolymer and/or the homopolymer block of the propylene block copolymer has an IR τ ≧0.98.  
     
     
         11 ) A process for producing polyolefin multilayer pipes of  claim 11 , wherein β-nucleated propylene polymers are propylene polymers produced by melt mixing propylene homopolymers and/or propylene copolymers with 0.0001 to 2.0% by weight, based on the polypropylenes used, β-nucleating agents at temperatures from 175 to 250° C.  
     
     
         12 ) Use of polyolefin multilayer pipes of any one of  claims 1  to  10  for non pressure pipe applications, preferably for outdoor use, for above as well as underground drainage and sewerage pipe systems, surface water pipes, pipes for cable protection, pipes for cold climate conditions and for indoor use, soil and waste water pipes.