Industrial polyolefin piping system

Abstract

Industrial polyolefin piping system with improved stiffness, impact strength for use at high service temperature, comprising single or multilayer pipes, fitting, chambers, valves and vessels, consisting of β-nucleated propylene homopolymers with an IRτ≧0.98 having a tensile modulus ≧1500 MPa, a Charpy impact strength, notched, at +23° C.≧30 kJ/m 2 and a Vicat B temperature >90° C. and a Heat Distortion Temperature >100° C. The industrial polyolefin piping system is suitable for chemical plant constructions comprising single or multilayer pipes, fittings, chambers, valves and vessels with improved stiffness, impact strength and high service temperature, preferred for conveyance of natural gas, dangerous liquids and/or toxic liquids.

1 . Industrial polyolefin piping system with improved stiffness and impact strength for use at high service temperature, comprising single- or multilayer pipes, fittings, valves, chambers and vessels, consisting essentially of a propylene homopolymer with a melt index of 0.05 to 40 g/10 min at 230° C./2.16 kg, wherein the propylene homopolymer is β-nucleated and has an IRτ≧0.98, having a tensile modulus ≧1500 MPa, a Charpy impact strength at +23° C. of ≧30 kJ/m 2 , using notched test specimens, a Vicat B temperature >90° C. and a heat distortion temperature >100° C.  
     
     
         2 . Industrial polyolefin piping system according to  claim 1 , comprising a propylene homopolymer with a melt index of 0.05 to 15 g/10 min at 230° C./2.16 kg.  
     
     
         3 . Industrial polyolefin piping system according to one of the claims  1  or  2 , wherein the β-nucleated propylene polymers with an IRτ≧0.98 are propylene polymers obtained by polymerization with a Ziegler-Natta catalyst system comprising titanium-containing solid components, an organoaluminum, 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 . Industrial polyolefin piping system according to  claim 3 , wherein the external donor is dicyclopentyldimethoxysilane.  
     
     
         5 . Industrial polyolefin piping system according to one of  claims 1  to  4 , wherein the β-nucleated propylene polymer contains 0.0001 to 2.0 wt %, based on the polypropylene 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 -C 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 6 -C 12 -aromatic monocarboxylic acids and C 5 -C 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 -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 monoamines, as β-nucleating agent.  
 
     
     
         6 . Industrial polyolefin piping system according to one of the  claims 1  to  4 , wherein in that the β-nucleated propylene polymer contains 0.0001 to 2.0 wt %, based on the polypropylene used, 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 . Industrial polyolefin piping system according to one of the  claims 1  to  4 , wherein the β-nucleated propylene polymer contains 0.01 to 2.0 wt %, based on the polypropylene used, 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 salts of metals from group IIa of periodic system, as β-nucleating agent.  
     
     
         8 . Industrial polyolefin piping system according to one of the  claims 1  to  4 , characterized in that the β-nucleated propylene polymer contains 0.01 to 2.0 wt %, based on the polypropylene used, 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 . Process for producing an industrial polyolefin piping system with improved stiffness, impact strength for use at high service temperature, comprising single- or multilayer pipe fabrication by extrusion of a propylene homopolymer with a melt index of 0.05 to 40 g/10 min at 230° C./2.16 kg at a melt temperature of 195 to 250° C., fitting and valve fabrication by injection molding of a propylene homopolymer with a melt index of 2 to 40 g/10 min at 230° C./2.16 kg at a melt temperature of 220 to 290° C., and vessel fabrication by blow molding of a propylene homopolymer with a melt index of 1 to 20 g/10 min at 230° C./2.16 kg at a melt temperature of 185 to 230° C., characterized in that the propylene homopolymers used are β-nucleated propylene homopolymers with an IRτ≧0.98 having a tensile modulus ≧1500 MPa, a Charpy impact strength, using notched test specimens, at 23° C.≧30 kJ/m 2 , a Vicat B temperature >90° C. and a heat distortion temperature >100° C.  
     
     
         10 . Use of an industrial polyolefin piping system according to one of  claims 1  to  7  for chemical plant constructions comprising pipes, fittings, valves and vessels with improved stiffness, impact strength and high service temperature for conveyance of fluids