WO2016201621A1

WO2016201621A1 - Polypropylene composition for pipe applications

Info

Publication number: WO2016201621A1
Application number: PCT/CN2015/081554
Authority: WO
Inventors: Xin Zhou; Shih Ping CHEN; Dongyu FANG
Original assignee: Borouge Compounding Shanghai Co., Ltd.
Priority date: 2015-06-16
Filing date: 2015-06-16
Publication date: 2016-12-22
Also published as: CN107636061A; CN107636061B

Abstract

Pipe comprising a polypropylene composition (PC) comprising (i) propylene homopolymer having an MFR₂ (230 ℃, 2, 16 kg) in the range of 2 to 100 g/10 min, (ii) polar modified polypropylene having an MFR₂ (190 ℃, 2, 16 kg) of at least 50 g/10 min, and (iii) fibers.

Description

POLYPROPYLENE COMPOSITION FOR PIPE APPLICATIONS

The present invention relates to a pipe having an improved deformation and crack resistance at elevated temperatures and pressures.

The term "pipe" as used according to the present invention is meant to comprise pipes in a broader sense including supplementary parts like pipe fittings, pipe valves, pipe chambers and all parts which are commonly applied for piping systems, in particular piping systems for the transport of pressurised fluids under elevated temperatures. The term "pipe" also comprises single or multilayer pipes and single or multilayer supplementary parts like pipe fittings, pipe valves, pipe chambers, and all parts which are commonly necessary for piping systems. The term "pipe" also includes structural wall pipes, such as corrugated pipes, double wall pipes with or without hollow sections.

Pipes made of polymeric materials are frequently used for various purposes, such as fluid transport, i.e. transport of gases or liquids. Furthermore, the fluid transport may be conducted pressurised, e.g. when transporting natural gas or tap water, or non-pressurised, e.g. when transporting sewage or drainage. Furthermore, the fluid transport may be conducted at varying temperatures, usually within the temperature range of from about 0 ℃ to about 100 ℃.

Different requirements are imposed on pipes for the transport of pressurised fluids, i.e. pressure pipes, and pipes for the transport of non-pressurised fluids, i.e. non-pressure pipes. While pressure pipes must be able to withstand an internal positive pressure, i.e. a pressure inside the pipe that is higher than the pressure outside the pipe, non-pressure pipes do not have to withstand any internal positive pressure, but are instead required to withstand an external positive pressure, i.e. the pressure outside the pipe is higher than the pressure inside the pipe. Furthermore, different requirements are imposed on pipes for the transport of fluids at ambient temperatures and pipes for the transport of fluids at elevated temperatures.

If fluids have to be transported in a piping system at elevated pressure and/or temperature, it is necessary that also the joints of the piping system maintain their desired properties, in particular it is required that the joints of the piping system withstand the pressure and/or temperature of the fluid over a long time, preferably over the entire lifetime of the piping system. Thus, also the pipe fittings used at the joints need to withstand the elevated pressure and/or temperature over a long time, preferably over the entire lifetime of the piping system. In particular, it is required that the pipe fittings do not deform or crack at elevated pressure and/or temperature as any deformation and/or crack on the surface may result in leakage or even bursting of the piping system during the use.

In a preferred embodiment the term “pipe” as used according to the present invention is directed at a pipe fitting. The term "pipe fitting" as used according to the present invention is directed at a joint piece or a connector piece, such as a coupler, an elbow, a stop end part, a spare nut, a tap, or a tee used in piping systems to connect pipes, and to connect pipes and supplementary parts for pipes.

Thus, in a preferred embodiment the present invention relates to a pipe fitting having an improved deformation and crack resistance at elevated pressures and/or temperatures.

Therefore, there is a need for pipes, in particular pipe fittings comprising a polymeric material with improved heat and/or pressure resistance and it is an object of the present invention to provide the same.

It is a finding of the present invention that pipes, in particular pipe fittings with improved heat and/or pressure resistance can be obtained when prepared from polypropylene compositions comprising polypropylene homopolymer, polar modified polypropylene and fibers.

In a first aspect the present invention is directed at a pipe, like a pipe fitting, comprising a polypropylene composition (PC) comprising (i) propylene homopolymer (HPP-1) having a MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 in the range of 2 to 100 g/10 min, (ii) polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min, and (iii) fibers (FB) .

In an embodiment the weight ratio between the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) [ (HPP-1) / (PMP) ] of the propylene composition (PC) according to the first aspect is in the range of 300 to 8, based on the weight of the polypropylene composition (PC) , and/or the weight ratio between the propylene homopolymer (HPP-1) and the fibers (FB) [wt. -％ (HPP-1) /wt. -％ (FB) ] of the propylene composition (PC) according to the first aspect is in the range of 5.5 to 0.5, based on the weight of the polypropylene composition (PC) .

In a second aspect the present invention is directed at a pipe, like a pipe fitting, comprising a polypropylene composition (PC) consisting of (i) propylene homopolymer (HPP-1) having a MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 in the range of 2 to 100 g/10 min, (ii) polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min, (iii) fibers (FB) , and (iv) additives (AD) .

In an embodiment the weight ratio between the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) [ (HPP-1) / (PMP) ] of the propylene composition (PC) according to the second aspect is in the range of 300 to 8, based on the weight of the polypropylene composition (PC) , and/or the weight ratio between the propylene homopolymer (HPP-1) and the fibers (FB) [ (HPP-1) / (FB) ] of the propylene composition (PC) according to the second aspect is in the range of 5.5 to 0.5, based on the weight of the polypropylene composition (PC) and/or the weight ratio between the propylene homopolymer (HPP-1) and the additives (AD) [ (HPP-1) / (AD) ] of the propylene composition (PC) according to the second aspect is in the range of 120 to 4, based on the weight of the polypropylene composition (PC) .

In an embodiment the polypropylene composition (PC) according to the first or the second aspect has a flexural modulus of at least 5000 MPa.

In an embodiment the polypropylene composition (PC) according to the first or the second aspect has a Vicat Softening Temperature Vicat B of at least 100 ℃.

In an embodiment the propylene homopolymer (HPP-1) according to the first or the second aspect is nucleated, preferably α-nucleated.

In an embodiment the propylene homopolymer (HPP-1) according to the first or the second aspect has a flexural modulus of at least 1600 MPa.

In an embodiment the polar modified polypropylene (PMP) according to the first or the second aspect comprises polar groups in an amount of at least 0.5 wt. -％.

In an embodiment the fibers (FB) according to the first or the second aspect are selected from the group consisting of glass fibers, ceramic fibers, graphite fibers and mixtures thereof.

In a third aspect the present invention is directed at a process for the preparation of a pipe according to the first or the second aspect, comprising the steps of

(i) providing polymer composition (PC) and

(ii) injection molding of the polymer composition (PC) to form a pipe.

In a fourth aspect the present invention is directed at the use of a polypropylene composition (PC) according to the first or the second aspect in a pipe to improve the heat and/or pressure resistance.

In the following the invention is described in more detail:

The Pipe

As indicated above the term "pipe" as used according to the present invention is meant to comprise pipes in a broader sense including supplementary parts like pipe fittings, pipe valves, pipe chambers and all parts which are commonly applied for piping systems, in particular piping systems for the transport of pressurised fluids under elevated temperatures.

In a preferred embodiment the term "pipe" is directed at supplementary parts like pipe fittings, pipe valves, and pipe chambers, in particular it is preferred that the term "pipe" is directed at a pipe fitting.

In the present invention the pipe, like the pipe fitting, comprises the polypropylene composition (PC) as defined in detail below. In a preferred embodiment the pipe, like the pipe fitting, comprises at least 60 wt. -％, more preferably at least 75 wt. -％, yet more preferably at least 90 wt. -％, still more preferably at least 95 wt. -％, still yet more preferably at least 99 wt. -％, based on the total weight of the pipe (like the pipe fitting) the polypropylene composition (PC) as defined in detail below.

The present invention is directed at a pipe, like a pipe fitting, comprising, like consisting of, a polypropylene composition (PC) comprising

(i) propylene homopolymer (HPP-1) having an MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 of not more than 100 g/10 min, preferably of not more than 50 g/10min, more preferably of not more than 30 g/10min, even more preferably of not more than 10 g/10min, like in the range of 2 to 100 g/10min, preferably in the range of 2 to 50 g/10min, more preferably in the range of 2 to 30 g/10min, even more preferably in the range of 2 to 10 g/10min

(ii) polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min, preferably at least 80 g/10min, like in the range of 50 to 150 g/10 min, preferably in the range of 70 to 140 g/10min, even more preferably in the range of 90 to 130 g/10min, yet even more preferably in the range of 100 to 115 g/10min, and

(iii) fibers (FB) .

Preferably the weight ratio between propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) [ (HPP-1) / (PMP) ] , based on the weight of the polypropylene composition (PC) , is in the range of 300 to 8, preferably in the range of 150 to 9, more preferably in the range of 100 to 15, even more preferably in the range to 70 to 25, yet even more preferably in the range of 50 to 30.

Preferably the weight ratio between propylene homopolymer (HPP-1) and the fibers (FB) [ (HPP-1) / (FB) ] , based on the weight of the polypropylene composition (PC) , is in the range of 5.5 to 0.5, preferably in the range of 4.0 to 0.8, more preferably in the range of 3.0 to 1.0, even more preferably in the range to 2.5 to 1.0.

The polypropylene composition (PC) may comprise

(i) the propylene homopolymer (HPP-1) in an amount of 45 to 75 wt. -％, preferably in an amount of 50 to 70 wt. -％, more preferably in an amount of 55 to 69 wt. ％

(ii) the polar modified polypropylene (PMP) in an amount of 0.1 to 5.0 wt. -％, preferably in an amount of 0.5 to 5.0 wt. -％, more preferably in an amount of 0.5 to 4.0 wt. -％, even more preferably in an amount of 1 to 3.0 wt. -％, and

(iii) the fibers (FB) in an amount of 20 to 50 wt. -％, preferably in an amount of 28 to 44 wt. -％, more preferably in an amount of 30 to 40 wt. -％,

based on the weight of the polypropylene composition (PC) .

It is appreciated that the pipe, like the pipe fitting, comprises, like consisting of, a polypropylene composition (PC) consisting of

(i) propylene homopolymer (HPP-1) having a MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 of not more than 100 g/10min, preferably of not more than 50 g/10min, more preferably of not more than 30 g/10min, even more preferably of not more than 10 g/10min, like in the range of 2 to 100 g/10min, preferably in the range of 2 to 50 g/10min, more preferably in the range of 2 to 30 g/10min, even more preferably in the range of 2 to 10 g/10min,

(ii) polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min, preferably of at least 80 g/10min, like in the range of 50 to 150 g/10min, more preferably in the range of 70 to 140 g/10min, even more preferably in the range of 90 to 130 g/10min yet even more preferably in the range of 100 to 115 g/10min,

(iii) fibers (FB) , and

(iv) additives (AD) .

Preferably the weight ratio between propylene homopolymer (HPP-1) and the additives (AD) [ (HPP-1) / (AD) ] , based on the weight of the polypropylene composition (PC) , is in the range of 120 to 4, preferably in the range of 100 to 6, more preferably in the range of 50 to 10, even more preferably in the range to 40 to 20.

Furthermore, it is appreciated that the pipe, like the pipe fitting, comprises, like consisting of, a polypropylene composition (PC) consisting of the propylene homopolymer (HPP-1) , the polar modified polypropylene (PMP) , the fibers (FB) and the additives (AD) , wherein

(i) the propylene homopolymer (HPP-1) is present in an amount of 45 to 75 wt. -％, more preferably in an amount of 50 to 70 wt. -％, even more preferably in an amount of 55 to 69 wt％,

(ii) the polar modified polypropylene (PMP) is present in an amount of 0.1 to 5 wt. -％, preferably in an amount of 0.5 to 5.0 wt. -％, more preferably in an amount of 0.5 to 4.0 wt. -％, even more preferably in an amount of 1.0 to 3.0 wt. -％, and

(iii) the fibers (FB) are present in an amount of 20 to 50 wt. -％, preferably in an amount of 28 to 44 wt. -％, more preferably in an amount of 30 to 40 wt. -％., and

(iv) the additives (AD) are present in an amount of 0.1 to 10 wt. ％, preferably in an amount of 0.1 to 5.0 wt. -％, more preferably in an amount of 0.5 to 3.5 wt. -％, even more preferably in an amount of 1.0 to 3.0 wt. -％,

based on the weight of the polypropylene composition (PC) .

In an embodiment the pipe, like the pipe fitting, does not comprise any other polymeric material in addition to the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) , in particular does not comprise any other polymeric material as base resin in addition to the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) .

In another embodiment the pipe, like the pipe fitting, does not comprise any other polymeric material in addition to the propylene homopolymer (HPP-1) , the polar modified polypropylene (PMP) and optionally the additives (AD) , in particular does not comprise any other polymeric material as base resin in addition to the propylene homopolymer (HPP-1) , the polar modified polypropylene (PMP) and optionally the additives (AD) .

As indicated above the present invention is directed at a pipe with improved heat and/or pressure resistance to meet the requirements imposed by transporting pressurized fluids at elevated temperatures.

Preferably the pipe comprises a polypropylene composition (PC) with a flexural modulus of at least 5000 MPa, preferably a polypropylene composition (PC) with a flexural modulus of at least 6000 MPa, more preferably a polypropylene composition (PC) with a flexural modulus of at least 6800 MPa, like in the range of 5000 to 20,000 MPa, preferably in the range of 6000 to 15,000 MPa, more preferably in the range of 6800 to 12,000 MPa.

Preferably the pipe comprises a polypropylene composition (PC) with a Vicat Softening Temperature Vicat B of at least 100 ℃, preferably a polypropylene composition (PC) with a Vicat Softening Temperature Vicat B of at least 120 ℃, more preferably a polypropylene composition (PC) with a Vicat Softening Temperature Vicat B of at least 140 ℃, even more preferably a polypropylene composition (PC) with a Vicat Softening Temperature Vicat B of at least 150 ℃, like in the range of 100 to 250 ℃, preferably in the range of 120 to 200 ℃, more preferably in the range of 140 to 180 ℃, even more preferably in the range of 155 to 175 ℃.

The Propylene Homopolymer (HPP-1)

The propylene homopolymer (HPP-1) is an essential component of the polypropylene composition (PC) comprised in the pipe according to the present invention.

It is appreciated that the propylene homopolymer (HPP-1) has a relatively low melt flow rate MFR₂ (230℃, 2.16 kg) measured according to ISO 1133 of not more than 100 g/10 min, preferably of not more than 50 g/10min, more preferably of not more than 30 g/10min, even more preferably of not more than 10 g/10min, like in the range of 2 to 100 g/10min, preferably in the range of 2 to 50 g/10min, more preferably in the range of 2 to 30 g/10min, even more preferably in the range of 2 to 10 g/10min.

Furthermore, it is appreciated that the propylene homopolymer (HPP-1) has a flexural modulus of at least 1600 MPa, preferably at least 1700 Mpa, more preferably at least 1900 Mpa, even more preferably at least 2000 Mpa, like in the range of 1600 to 4000 MPa, preferably in the range of 1700 to 3000 MPa, more preferably in the range of 1800 to 3000 MPa, even more preferably in the range of 2000 to 2500 MPa.

Furthermore, it is appreciated that the propylene homopolymer (HPP-1) is a crystalline polymer. The term “crystalline” indicates that the propylene homopolymer has a rather high melting temperature. Throughout the description the propylene homopolymer (HPP-1) is regarded as crystalline unless otherwise indicated. Preferably the propylene homopolymer (HPP-1) has a melting temperature measured by differential scanning calorimetry (DSC) of at least 155 ℃, more preferably at least 160 ℃, even more preferably at least 164 ℃, like in the range of 155 to 180 ℃, preferably in the range of 160 to 175 ℃, more preferably in the range of 164 to 170 ℃.

Accordingly, it is appreciated that the propylene homopolymer (HPP-1) is nucleated, in particular α-nucleated.

In case the propylene homopolymer (HPP-1) comprises an α-nucleating agent, it is preferred that it is free of β-nucleating agents. The α-nucleating agent is preferably selected from the group consisting of

(i) salts of monocarboxylic acids and polycarboxylic acids, e.g. sodium benzoate or aluminum tert-butylbenzoate, and

(ii) dibenzylidenesorbitol (e.g. 1, 3 : 2, 4 dibenzylidenesorbitol) and C₁-C₈-alkyl-substituted dibenzylidenesorbitol derivatives, such as methyldibenzylidenesorbitol, ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol (e.g. 1, 3 : 2, 4 di (methylbenzylidene) sorbitol) , or substituted nonitol-derivatives, such as 1, 2, 3, -trideoxy-4, 6: 5, 7-bis-O- [ (4-propylphenyl) methylene] -nonitol, and

(iii) salts of diesters of phosphoric acid, e.g. sodium 2, 2'-methylenebis (4, 6, -di-tert-butylphenyl) phosphate or aluminium-hydroxy-bis [2, 2' -methylene-bis (4, 6-di-t-butylphenyl) phosphate] , and

(iv) vinylcycloalkane polymer or vinylalkane polymer, and

(v) mixtures thereof.

Prederably the α-nucleating agent comprised in the propylene homopolymer (HPP-1) is vinylcycloalkane polymer and/or vinylalkane polymer, more preferably vinylcycloalkane polymer, like vinylcyclohexane (VCH) polymer. Vinyl cyclohexane (VCH) polymer is particularly preferred as α-nucleating agent. It is appreciated that the amount of vinylcycloalkane, like vinylcyclohexane (VCH) , polymer and/or vinylalkane polymer, more preferably of vinylcyclohexane (VCH) polymer, in the propylene homopolymer (HPP-1) is not more than 500 ppm, preferably not more than 200 ppm, more preferably not more than 100 ppm, like in the range of 0.1 to 500 ppm, preferably in the range of 0.5 to 200 ppm, more preferably in the range of 1 to 100 ppm. Furthermore, it is appreciated that the vinylcycloalkane polymer and/or vinylalkane polymer is introduced into the propylene homopolymer (HPP-1) by the BNT technology. With regard to the BNT-technology reference is made to the international applications WO 99/24478, WO 99/24479 and particularly WO 00/68315. According to this technology a catalyst system, preferably a Ziegler-Natta procatalyst, can be modified by polymerizing a vinyl compound in the presence of the catalyst system, comprising in particular the special Ziegler-Natta procatalyst, an external donor and a cocatalyst, which vinyl compound has the formula:

CH₂＝CH-CHR³R⁴

wherein R³ and R⁴ together form a 5-or 6-membered saturated, unsaturated or aromatic ring or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is used for the preparation of the propylene homopolymer (HPP-1) according to this invention. The polymerized vinyl compound acts as an α-nucleating agent. The weight ratio of vinyl compound to solid catalyst component in the modification step of the catalyst is preferably of up to 5 (5:1) , more preferably up to 3 (3:1) , like in the range of 0.5 (1:2) to 2 (2:1) .

Such nucleating agents are commercially available and are described, for example, in "Plastic Additives Handbook" , 5th edition, 2001 of Hans Zweifel (pages 967 to 990) .

The propylene homopolymer (HPP-1) is preferably multimodal in, in particular bimodal, in its molecular weight fraction. In this case the propylene homopolymer (HPP-1) comprises at least two fractions, preferably consist of two fractions, the fractions are a first propylene homopolymer fraction (HPP-1a) and a second propylene homopolymer fraction (HPP-1b) . Preferably the two fractions differ in the melt flow rate MFR₂ (230℃, 2.16 kg load) . Preferably the melt flow rate MFR₂ (230℃, 2.16 kg load) of the first propylene homopolymer fraction (HPP-1a) is lower than the melt flow rate MFR₂ (230℃, 2.16 kg load) of the second propylene homopolymer fraction (HPP-1b) . It is appreciated that the melt flow rate MFR₂ (230℃, 2.16 kg load) of the first propylene homopolymer fraction (HPP-1a) differs from the melt flow rate MFR₂ (230℃, 2.16 kg load) of the second propylene homopolymer fraction (HPP-1b) by at least 2 g/10min, preferably by at least 5 g/10min, more preferably by at least 10 g/10 min, like in therange from 2 to 100 g/10min, preferably in a range from 10 to 80 g/10min, more preferably in a range of 30 to 50 g/10min.

As will be explained below, the propylene homopolymer (HPP-1) can be produced by blending different polymer types, i.e. of different molecular weight. However it is preferred that the propylene homopolymer (HPP-1) isproduced in a sequential step process, using reactors in serial configuration and operating at different reaction conditions. As a consequence, each fraction prepared in a specific reactor will have its own molecular weight distribution.

In other words the propylene homopolymer (HPP-1) is preferably produced in a sequential polymerization process, i.e. in a multistage process, known in the art, wherein the propylene homopolymer (HPP-1) is produced at least in one slurry reactor, preferably in at least one slurry reactor and optionally in at least one subsequent gas phase reactor, more preferably in one slurry reactor and one subsequent gas phase reactor.

Accordingly it is preferred that the propylene homopolymer (HPP-1) is produced in a sequential polymerization process comprising the steps of

(a) polymerizing propylene in a first reactor (R1) and obtaining the first polypropylene homopolymer fraction (HPP-1a) ,

(b) transferring the first polypropylene fraction (HPP-1a) into a second reactor (R2) ,

(c) polymerizing in the second reactor (R2) in the presence of said first polypropylene fraction (HPP-1a) propylene and obtaining thereby the second polypropylene fraction (HPP-1b) , said first polypropylene fraction (HPP-1a) and said second polypropylene fraction (HPP-1b) form the polypropylene homopolymer (HPP-1) .

It is preferred that the propylene homopolymer (HPP-1) is obtained in a sequential polymerization process comprising a first reactor (R1) wherein the first polypropylene fraction (HPP-1a) is prepared and a second reactor (R2) wherein the second polypropylene fraction (HPP-1b) is prepared. In a preferred embodiment the reactor split between the first reactor (R1) wherein the first polypropylene fraction (HPP-1a) is prepared and the second reactor (R2) wherein the second polypropylene fraction (HPP-1b) is prepared [R1/R2] is in the range of 20:80 to 80:20, preferably in the range of 30:70 to 70:30, more preferably 40:60 to 60:40, even more preferably in the range of 45:55 to 55:45, like 50:50.

Accordingly the propylene homopolymer (HPP-1) may comprise a first polypropylene fraction (HPP-1a) and a second polypropylene fraction (HPP-1b) , preferably consists of a first polypropylene fraction (HPP-1a) and a second polypropylene fraction (HPP-1b) , wherein the weight ratio of the first polypropylene fraction (HPP-1) to the second polypropylene fraction (HPP-1b) [ (HPP-1a) / (HPP-1b) ] , in the propylene homopolymer (HPP-1) , is in the range of 0.25 to 4, preferably in the range of 0.43 to 2.33, more preferably in the range of 0.66 to 1.50, even more preferably in the range of 0.90 to 1.22, based on the weight of the propylene homopolymer (HPP-1) . In other words it is preferred that the propylene homopolymer (HPP-1) comprises the first polypropylene fraction (HPP-1a) in an amount of at least 20 wt. ％, preferably in an amount of at least 30 wt. -％, more preferably in an amount of at least 40 wt. -％, even more preferably in an amount of at least 45 wt. -％, like in the range of 20 to 80 wt. ％, preferably in the range of 30 to 70 wt. -％, more preferably in the range of 40 to 60 wt. -％, even more preferably in the range of 45 to 55 wt. -％, based on the weight of the propylene homopolymer (HPP-1) and/or the second polypropylene fraction (HPP-1b) in an amount of not more than 80 wt. ％, preferably in an amount of not more than 70 wt. -％, more preferably in an amount of not more than 60 wt. ％, even more preferably in an amount of not more than 55 wt. -％, like in the range of 80 to 20 wt. ％, preferably in the range of 70 to 30 wt. -％, more preferably in the range of 60 to 40 wt. -％, even more preferably in the range of 55 to 45 wt. -％, based on the weight of the propylene homopolymer (HPP-1)

Of course, in the first reactor (R1) the second polypropylene fraction (HPP-1b) can be produced and in the second reactor (R2) the first polypropylene fraction (HPP-1a) can be obtained.

It is appreciated that the propylene homopolymer (HPP-1) comprises a first polypropylene fraction (HPP-1a) and a second polypropylene fraction (HPP-1b) , preferably consists of a first polypropylene fraction (HPP-1a) and a second polypropylene fraction (HPP-1b) , wherein first polypropylene fraction (HPP-1a) is different to the second polypropylene fraction (HPP-1b) . In particular it is appreciated that the first polypropylene fraction (HPP-1a) has a different MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, compared to the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the second polypropylene fraction (HPP-1b) . In a preferred embodiment the first polypropylene fraction (HPP-1a) has a lower MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, compared to the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the second polypropylene fraction (HPP-1b) .

The first polypropylene fraction (HPP-1a) may have an MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of not more than 5.0, preferably of not more than 3.0, more preferably of not more than 2.5, even more preferably of not more than 2.0, like in the range of 0.5 to 5.0, preferably in the range of 0.5 to 3.0, more preferably in the range of 1.0 to 2.5, even more preferably in the range of 1.0 to 2.0.

Still more preferably the ratio of the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the propylene homopolymer (HPP-1) to the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the first polypropylene fraction (HPP-1a) [MFR₂ (HPP-1) /MFR₂ (HPP-1a) ] is not more than 20, preferably not more than 15, more preferably not more than 10, even more preferably not more than 8.0, yet even more preferably not more than 7.0, like in the range of 1.0 to 20, preferably in the range of 2.0 to 15, more preferably in the range of 3.0 to 10, even more preferably in the range of 4.0 to 8.0, like in the range of 4.0 to 6.0.

The term “sequential polymerization process” indicates that the propylene homopolymer (HPP-1) is produced in at least two, like three or four reactors connected in series, preferably two reactors in series. Accordingly the present process comprises at least a first reactor (R1) and at least a second reactor (R2) , preferably a first reactor (R1) and a second reactor (R2) . The term “polymerization reactor” shall indicate that the main polymerization takes place. Thus in case the process consists of two polymerization reactors, this definition does not exclude the option that the overall process comprises for instance a pre-polymerization step in a pre-polymerization reactor. The term “consist of” is only a closing formulation in view of the main polymerization reactors.

The first reactor (R1) is preferably a slurry reactor (SR) and can be any continuous or simple stirred batch tank reactor or loop reactor operating in bulk or slurry. Bulk means a polymerization in a reaction medium that comprises of at least 60 ％ (w/w) monomer. According to the present invention the slurry reactor (SR) is preferably a (bulk) loop reactor (LR) .

The second reactor (R2) , and any further reactors are preferably gas phase reactors (GPR) . Such gas phase reactors (GPR) can be any mechanically mixed or fluid bed reactors. Preferably the gas phase reactors (GPR) comprise a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec. Thus it is appreciated that the gas phase reactor is a fluidized bed type reactor preferably with a mechanical stirrer.

Thus in a preferred embodiment the first reactor (R1) is a slurry reactor (SR) , like a loop reactor (LR) , whereas the second reactor (R2) is a gas phase reactor (GPR) . Accordingly for the instant process at least two, preferably two polymerization reactors, namely a slurry reactor (SR) , like a loop reactor (LR) , and a first gas phase reactor (GPR-1) connected in series are used. If needed prior to the slurry reactor (SR) a pre-polymerization reactor is placed.

A preferred multistage process is a “loop-gas phase” -process, such as developed by Borealis A/S, Denmark (known as

technology) described e.g. in patent literature, such as in EP 0 887 379, WO 92/12182 WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 or in WO 00/68315.

A further suitable slurry-gas phase process is the

process of Basell.

Preferably, in the instant process for producing the propylene homopolymer (HPP-1) as defined above the conditions for the first reactor (R1) , i.e. the slurry reactor (SR) , like a loop reactor (LR) , of step (a) may be as follows:

- the temperature is within the range of 50 ℃ to 110 ℃, preferably between 60 ℃ and 100 ℃, more preferably between 68 and 95 ℃,

- the pressure is within the range of 20 bar to 80 bar, preferably between 40 bar to 70 bar,

- hydrogen can be added for controlling the molar mass in a manner known per se.

Subsequently, the reaction mixture from step (a) is transferred to the second reactor (R2) , i.e. gas phase reactor (GPR-1) , i.e. to step (c) , whereby the conditions in step (c) are preferably as follows:

- the temperature is within the range of 50 ℃ to 130 ℃, preferably between 60 ℃ and 100 ℃,

- the pressure is within the range of 5 bar to 50 bar, preferably between 15 bar to 35 bar,

The residence time can vary in the two reactor zones.

In one embodiment of the process for producing the propylene homopolymer (HPP-1) the residence time in bulk reactor, e.g. loop, is in the range 0.1 to 2.5 hours, e.g. 0.15 to 1.5 hours, and the residence time in gas phase reactor will generally be 0.2 to 6.0 hours, like 0.5 to 4.0 hours.

If desired, the polymerization may be effected in a known manner under supercritical conditions in the first reactor (R1) , i.e. in the slurry reactor (SR) , like in the loop reactor (LR) , and/or as a condensed mode in the gas phase reactors (GPR) .

The process may comprise also a prepolymerization with the catalyst system, as described in detail below, comprising a Ziegler-Natta procatalyst, an external donor and optionally a cocatalyst.

In a preferred embodiment, the prepolymerization is conducted as bulk slurry polymerization in liquid propylene, and optionally inert components dissolved therein.

The prepolymerization reaction is typically conducted at a temperature of 10 to 60 ℃, preferably from 15 to 50 ℃, and more preferably from 20 to 45 ℃.

The pressure in the prepolymerization reactor is not critical but must be sufficiently high to maintain the reaction mixture in liquid phase. Thus, the pressure may be from 20 to 100 bar, for example 30 to 70 bar.

The catalyst components are preferably all introduced to the prepolymerization step. However, where the solid catalyst component (i) and the cocatalyst (ii) can be fed separately it is possible that only a part of the cocatalyst is introduced into the prepolymerization stage and the remaining part into subsequent polymerization stages. Also in such cases it is necessary to introduce so much cocatalyst into the prepolymerization stage that a sufficient polymerization reaction is obtained therein.

It is possible to add other components also to the prepolymerization stage. Thus, hydrogen may be added into the prepolymerization stage to control the molecular weight of the prepolymer as is known in the art. Further, antistatic additive may be used to prevent the particles from adhering to each other or to the walls of the reactor.

The precise control of the prepolymerization conditions and reaction parameters is within the skill of the art.

According to the invention the propylene homopolymer (HPP-1) is obtained by a multistage polymerization process, as described above, in the presence of a catalyst system comprising a Ziegler-Natta procatalyst which contains a trans-esterfication product of a lower alcohol and a phthalic ester as the solid catalyst component (i) .

The procatalyst used according to the invention for preparing the propylene homopolymer (HPP-1) is prepared by

a) reacting a spray crystallized or emulsion solidified adduct of MgCl₂ and a C₁-C₂ alcohol with TiCl₄

b) reacting the product of stage a) with a dialkylphthalate of formula (I)

wherein R^1’ a nd R^2’ are independently at least a C₅ alkyl under conditions where a transesterification between said C₁ to C₂ alcohol and said dialkylphthalate of formula (I) takes place to form the internal donor

c) washing the product of stage b) or

d) optionally reacting the product of step c) with additional TiCl₄.

The procatalyst is produced as defined for example in the patent applications WO 87/07620, WO 92/19653, WO 92/19658 and EP 0 491 566. The content of these documents is herein included by reference.

First an adduct of MgCl₂ and a C₁-C₂ alcohol of the formula MgCl₂*nROH, wherein R is methyl or ethyl and n is 1 to 6, is formed. Ethanol is preferably used as alcohol.

The adduct, which is first melted and then spray crystallized or emulsion solidified, is used as catalyst carrier.

In the next step the spray crystallized or emulsion solidified adduct of the formula MgCl₂*nROH, wherein R is methyl or ethyl, preferably ethyl and n is 1 to 6, is contacting with TiCl₄ to form a titanized carrier, followed by the steps of

·adding to said titanised carrier

(i) a dialkylphthalate of formula (I) with R^1’ and R^2’ being independently at least a C₅-alkyl, like at least a C₈-alkyl,

or preferably

(ii) a dialkylphthalate of formula (I) with R^1’ and R^2’ being the same and being at least a C₅-alkyl, like at least a C₈-alkyl,

or more preferably

(iii) a dialkylphthalate of formula (I) selected from the group consisting of propylhexylphthalate (PrHP) , dioctylphthalate (DOP) , di-iso-decylphthalate (DIDP) , and ditridecylphthalate (DTDP) , yet more preferably the dialkylphthalate of formula (I) is a dioctylphthalate (DOP) , like di-iso-octylphthalate or diethylhexylphthalate, in particular diethylhexylphthalate,

to form a first product,

·subjecting said first product to suitable transesterification conditions, i.e. to a temperature above 100 ℃, preferablybetween 100 to 150 ℃, more preferably between 130 to 150 ℃, such that said methanol or ethanol is transesterified with said ester groups of said dialkylphthalate of formula (I) to form preferably at least 80 mol-％, more preferably 90 mol-％, most preferably 95 mol. -％, of a dialkylphthalate of formula (II)

with R¹ and R² being methyl or ethyl, preferably ethyl,

the dialkylphthalat of formula (II) being the internal donor and

·recovering said transesterification product as the procatalyst composition (component (i) ) .

The adduct of the formula MgCl₂*nROH, wherein R is methyl or ethyl and n is 1 to 6, is in a preferred embodiment melted and then the melt is preferably injected by a gas into a cooled solvent or a cooled gas, whereby the adduct is crystallized into a morphologically advantageous form, as for example described in WO 87/07620.

This crystallized adduct is preferably used as the catalyst carrier and reacted to the procatalyst useful in the present invention as described in WO 92/19658 and WO 92/19653.

As the catalyst residue is removed by extracting, an adduct of the titanised carrier and the internal donor is obtained, in which the group deriving from the ester alcohol has changed.

In case sufficient titanium remains on the carrier, it will act as an active element of the procatalyst.

Otherwise the titanization is repeated after the above treatment in order to ensure a sufficient titanium concentration and thus activity.

Preferably the procatalyst used according to the invention contains 2.5 wt. -％of titanium at the most, preferably 2.2％wt. -％at the most and more preferably 2.0 wt. -％at the most. Its donor content is preferably between 4 to 12 wt. -％and more preferably between 6 and 10 wt. -％.

More preferably the procatalyst used according to the invention has been produced by using ethanol as the alcohol and dioctylphthalate (DOP) as dialkylphthalate of formula (I) , yielding diethyl phthalate (DEP) as the internal donor compound.

Still more preferably the catalyst used according to the invention is the catalyst described in the example section； especially with the use of dioctylphthalate as dialkylphthalate of formula (I) .

For the production of the propylene homopolymer (HPP-1) according to the invention the catalyst system used preferably comprises in addition to the special Ziegler-Natta procatalyst an organometallic cocatalyst as component (ii) .

Accordingly it is preferred to select the cocatalyst from the group consisting of trialkylaluminium, like triethylaluminium (TEA) , dialkyl aluminium chloride and alkyl aluminium sesquichloride.

Component (iii) of the catalysts system used is an external donor represented by formula (IIIa) or (IIIb) . Formula (IIIa) is defined by

Si (OCH₃) ₂R₂ ⁵ (IIIa)

wherein R⁵ represents a branched-alkyl group having 3 to 12 carbon atoms, preferably a branched-alkyl group having 3 to 6 carbon atoms, or a cyclo-alkyl having 4 to 12 carbon atoms, preferably a cyclo-alkyl having 5 to 8 carbon atoms.

It is in particular preferred that R⁵ is selected from the group consisting of iso-propyl, iso-butyl, iso-pentyl, tert. -butyl, tert. -amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

Formula (IIIb) is defined by

Si (OCH₂CH₃) ₃ (NR^xR^y) (IIIb)

wherein R^x and R^y can be the same or different and represent a hydrocarbon group having 1 to 12 carbon atoms.

R^x and R^y are independently selected from the group consisting of linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms. It is in particular preferred that R^x and R^y are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, tert. -butyl, tert. -amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

More preferably both R^x and R^y are the same, yet more preferably both R^x and R^y are an ethyl group.

More preferably the external donor is of formula (IIIa) , like dicyclopentyl dimethoxy silane [Si (OCH₃) ₂ (cyclo-pentyl) ₂] or diisopropyl dimethoxy silane [Si (OCH₃) ₂ (CH (CH₃) ₂) ₂] .

Most preferably the external donor of formula (IIIb) is diethylaminotriethoxysilane.

The propylene homopolymer (HPP-1) is state of the art and a commercially available product.

The Polar Modified Polypropylene (PMP)

The polar modified polypropylene (PMP) is present in the polypropylene composition (PC) to achieve an easier and more uniform dispersion of the fibers (FB) in the polymer components which act as a matrix in the fiber reinforced composition.

The polar modified polypropylene (PMP) is preferably a polypropylene containing polar groups, preferably a propylene homopolymer containing polar groups.

In terms of structure, the polar modified polypropylene (PMP) is preferably selected from graft or block copolymers. Preferably the polar modified polypropylene (PMP) is a graft propylene copolymer comprising propylene in the main chain and polar groups in the side chain. In this context, preference is given to a polar modified polypropylene (PMP) containing polar groups selected from the group consisting of acid anhydrides, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl compounds, oxazoline and epoxides.

Specific examples of the said polar groups are unsaturated cyclic anhydrides and their aliphatic diesters, and the diacid derivatives. In particular, one can use maleic anhydride and compounds selected from C₁ to C₁₀ linear and branched dialkyl maleates, C₁ to C₁₀ linear and branched dialkyl fumarates, itaconic anhydride, C₁ to C₁₀ linear and branched itaconic acid dialkyl esters, maleic acid, fumaric acid, itaconic acid, acrylic acid and esters thereof, methacrylic acid and esters thereof, like glycidyl methacrylate, and mixtures thereof. Preferably the polar groups are selected from the group consisting of maleic anhydride, glycidyl methacrylate and mixtures thereof. In particular it is preferred that the polar group is maleic anhydride.

Particular preference is given to using a propylene polymer grafted with maleic anhydride as the polar modified polypropylene (PMP) , i.e. the adhesion promotor (AP) .

The polar modified polypropylene (PMP) can be produced in a simple manner by reactive extrusion of the polymer, for example with maleic anhydride in the presence of free radical generators (like organic peroxides) , as disclosed for instance in EP 0 572 028.

Preferred amounts of groups deriving from polar groups in the polar modified polypropylene (PMP) are from 0.5 to 3.0 wt. -％, preferably from 0.5 to 2.0 wt. -％, more preferably from 0.8 to 1.8 wt. -％.

It is appreciated that the melt flow rate MFR₂ (190 ℃) for the polar modified polypropylene (PMP) is at least 50 g/10min, preferably at least 80 g/10min, like in the range of 50 to 150 g/10min, preferably in the range of 70 to 140 g/10min, more preferably in the range of 90 to 130 g/10min, even more preferably in the range of 100 to 115 g/10min.

The polar modified polypropylene (PMP) is known in the art and commercially available.

The Fibers (FB)

The fibers (FB) are present in the polypropylene composition (PC) to provide a sufficient modulus and strength to the pipes, like the pipe fittings.

The fibers (FB) may be selected from the group consisting of glass fiber, mineral fiber, ceramic fiber and graphite fiber.

In an embodiment the fibers (FB) are glass fibers, preferably continuous glass fibers or cut glass fibers, also known as short fibers or chopped strands. Cut glass fibers are particularly preferred.

Preferably, the fibers (FB) , more preferably the glass fibers have an average length in the range of 1 to 10 mm, more preferably in the range of 1 to 7 mm, even more preferably in the range of 3 to 6 mm, yet even more preferably in the range of 4 to 5 mm.

Preferably, the fibers (FB) , more preferably the glass fibers have an average diameter in the range of 5 to 50 μm, preferably in the range of 10 to 40 μm, more preferably in the range of 10 to 30 μm, even more preferably in the range of 10 to 20 μm.

The Additives (AD)

The polypropylene composition (PC) may comprise additives (AD) . The additives are applied depending on the components comprised in the polypropylene composition (PC) and the intended field of application. Typical additives are acid scavengers, antioxidants, colorants, light stabilisers, heat stabilisers, anti-scratch agents, processing aids, lubricants, pigments, and the like. Accordingly in one embodiment the additives (AD) are selected from the group consisting of acid scavengers, antioxidants, colorants, light stabilisers, heat stabilisers, anti-scratch agents, processing aids, lubricants and pigments. Such additives are commercially available and for example described in “Plastic Additives Handbook” , 6^th edition 2009 of Hans Zweifel (pages 1141 to 1190) .

Furthermore, the term “additives” according to the present invention also includes carrier materials, in particular polymeric carrier materials (PCM) . The polymeric carrier materials (PCM) are preferably applied in form of a powder.

Preferably the polypropylene composition (PC) comprises the additives (AD) in an amount in the range of 0.1 to 20 wt. -％, preferably in the range of 0.5 to 10 wt. -％, more preferably in the range of 0.5 to 5 wt. -％, even more preferably in the range of 1 to 3 wt. -％, based on the weight of the polypropylene composition (PC) .

In a preferred embodiment the polypropylene composition (PC) comprises antioxidant (AO) , light stabilizing agent (LSA) and/or polymeric carrier material (PCM) as additives (AD) .

The Polymeric Carrier Material (PCM)

Preferably the polypropylene composition (PC) does not comprise (a) further polymer (s) different to the polymer (s) comprised in the polymers polypropylene composition (PC) , i.e. the polypropylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) in an amount exceeding 10 wt. -％, preferably in an amount exceeding 5 wt. -％, even more preferably in an amount exceeding 2 wt. -％, based on the weight of the polypropylene composition (PC) . If an additional polymer is present, such a polymer may be a polymeric carrier material (PCM) for additives.

It is appreciated that the polypropylene composition (PC) comprises polymeric carrier material (PCM) in an amount of not more than 10.0 wt. -％, preferably in an amount of not more than 5.0 wt. -％, more preferably in an amount of not more than 2 wt. -％, like in the range of 0.1 to 10 wt. -％, preferably in the range of 0.1 to 5 wt. -％, more preferably in the range of 0.5 to 2 wt. -％, based on the weight of the polypropylene composition (PC) .

The polymeric carrier material (PCM) is a carrier polymer for the other additives to ensure a uniform distribution in the polypropylene composition (PC) . The polymeric carrier material (PCM) is not limited to a particular polymer. The polymeric carrier material (PCM) may be ethylene homopolymer, ethylene copolymer obtained from ethylene and α-olefin comonomer such as C₃ to C₈ α-olefin comonomer, propylene homopolymer and/or propylene copolymer obtained from propylene and α-olefin comonomer such as ethylene and/or C₄ to C₈ α-olefin comonomer.

According to a preferred embodiment the polymeric carrier material (PCM) is a polypropylene homopolymer, this propylene homopolymer may be the same propylene homopolymer as the propylene homopolymer (HPP-1) or the polar modified polypropylene (PMP) , however, it is preferred that propylene homopolymer present as the polymeric carrier material (PCM) is different to the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) .

Process for the Preparation of a Polypropylene Composition (PC)

The polypropylene composition (PC) can be prepared by a process comprising the steps of adding

(i) propylene homopolymer (HPP-1) ,

(ii) polar modified polypropylene (PMP) ,

(iii) fibers (FB) , and

(iv) optionally additives (AD)

to an extruder and extruding the same, obtaining the polypropylene composition (PC) .

In a preferred embodiment the additives (AD) are premixed with polymeric carrier material (PCM) to yield an additive composition which is subsequently added to the extruder.

The extrusion process is usually conducted at elevated temperatures. It is appreciated that the extrusion process is conducted at temperatures of at least 160 ℃, preferably at temperatures of at least 180 ℃, more preferably at temperatures of at least 200 ℃, like in the range of 160 to 350 ℃, preferably in the range of 180 to 300 ℃, more preferably in the range of 180 to 250 ℃.

The polypropylene composition (PC) , the propylene homopolymer (HPP-1) , the polar modified polypropylene (PMP) , the fibers (FB) , the additives (AD) and the polymeric carrier material (PCM) are described in more detail above and below, in particular in the sections "The Polypropylene Composition (PC) " , "The Propylene Homopolymer (HPP-1) " , "The Polar Modified Polypropylene (PMP) " , "The Fibers (FB) " , "The Additives (AD) "and "The Polymeric Carrier Material (PCM) " .

Process for the Preparation of a Pipe

Furthermore, the present invention is directed at a process for the preparation of a pipe, like a pipe fitting, comprising the steps of

(i) providing a polymer composition (PC) and

(ii) injection molding of the polymer composition to form a pipe, like a pipe fitting.

The polypropylene composition (PC) is described in more detail above and below, in particular in the section "The Polypropylene Composition (PC) " .

In a preferred embodiment the pipe, in particular the pipe fitting comprises the polypropylene composition in an amount of at least at least 80 wt. -％, preferably in an amount of at least 90 wt. -％, more preferably in an amount of at least at least 95 wt. -％, like in the range of 80 to 100 wt. ％, preferably in the range of 90 to 100 wt. -％, more preferably in the range of 95 to 100 wt. -％.

Use of Polypropylene Composition (PC) for the Preparation of a Pipe

Furthermore, the present invention is directed at the use of the polypropylene composition (PC) in the preparation of a pipe, like a pipe fitting, to improve the heat and/or pressure resistance.

EXAMPLES

1. Definitions/Measuring Methods

The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined.

Quantification of microstructure by NMR spectroscopy

Quantitative nuclear-magnetic resonance (NMR) spectroscopy is used to quantify the isotacticity and regio-regularity of the polypropylene homopolymers.

Quantitative ¹³C {¹H} NMR spectra were recorded in the solution-state using a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for ¹H and ¹³C respectively. All spectra were recorded using a ¹³C optimised 10 mm extended temperature probehead at 125℃ using nitrogen gas for all pneumatics.

For polypropylene homopolymers approximately 200 mg of material was dissolved in 1, 2-tetrachloroethane-d₂ (TCE-d₂) . To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution needed for tacticity distribution quantification (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443； Busico, V.； Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251) . Standard single-pulse excitation was employed utilising the NOE and bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225； Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289) . A total of 8192 (8k) transients were acquired per spectra.

Quantitative ¹³C {¹H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs.

For polypropylene homopolymers all chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

Characteristic signals corresponding to regio defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253；； Wang, W-J., Zhu, S., Macromolecules 33 (2000) , 1157； Cheng, H. N., Macromolecules 17 (1984) , 1950) or comonomer were observed.

The tacticity distribution was quantified through integration of the methyl region between 23.6-19.7 ppm correcting for any sites not related to the stereo sequences of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443； Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251) .

Specifically the influence of regio-defects and comonomer on the quantification of the tacticity distribution was corrected for by subtraction of representative regio-defect and comonomer integrals from the specific integral regions of the stereo sequences. The isotacticity was determined at the pentad level and reported as the percentage of isotactic pentad (mmmm) sequences with respect to all pentad sequences: [mmmm] ％＝ 100* (mmmm/sum of all pentads)

The presence of 2, 1 erythro regio-defects was indicated by the presence of the two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites. Characteristic signals corresponding to other types of regio-defects were not observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253) .

The amount of 2, 1 erythro regio-defects was quantified using the average integral of the two characteristic methyl sites at 17.7 and 17.2 ppm:

P_21e＝ (I_e6+ I_e8) /2

The amount of 1, 2 primary inserted propene was quantified based on the methyl region with correction undertaken for sites included in this region not related to primary insertion and for primary insertion sites excluded from this region:

P₁₂＝ I_CH3+ P_12e

The total amount of propene was quantified as the sum of primary inserted propene and all other present regio-defects:

P_total＝ P₁₂+ P_21e

The mole percent of 2, 1-erythro regio-defects was quantified with respect to all propene: [21e] mol. -％＝ 100 * (P_21e/P_total)

Characteristic signals corresponding to the incorporation of ethylene were observed (as described in Cheng, H. N., Macromolecules 1984, 17, 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer.

The comonomer fraction was quantified using the method of W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157, through integration of multiple signals across the whole spectral region in the ¹³C {¹H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents.

The mole percent comonomer incorporation was calculated from the mole fraction.

The weight percent comonomer incorporation was calculated from the mole fraction.

MFR₂ (230℃) is measured according to ISO 1133 (230℃, 2.16 kg load) .

MFR₂ (190℃) is measured according to ISO 1133 (190℃, 2.16 kg load) .

Melting temperature (T_m) : measured with a TA Instrument Q2000 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC is run according to ISO 11357/part 3 /method C2 in a heat /cool /heat cycle with a scan rate of 10 ℃/min in the temperature range of -30 to +225℃. Melting temperature is determined from the second heating step.

The xylene cold solubles (XCS) content is determined at 25 ℃ according to ISO 16152； first edition； 2005-07-01

The Flexural Modulus was determined in 3-point-bending according to ISO 178 on injection molded specimens of 80 x 10 x 4 mm prepared in accordance with ISO 294-1: 1996.

The Charpy Notched Impact Strength (Charpy NIS) is measured according to ISO 179 2C /DIN 53453 at 23℃, using injection molded bar test specimens of 80x10x4 mm³ prepared in accordance with ISO 294-1: 1996.

The Izod Notched Impact Strength (Izod NIS) is measured according to ISO 180/1A at 23℃by using injection moulded test specimens as described in EN ISO 1873-2 (80×10×4mm) .

The Heat Deformation Temperature (HDT) is determined according to ISO 75-2 using a Ceast 6921 of

GmbH, Germany.

The Vicat Softening Temperature Vicat B is determined according to ISO 306 (A50) at a load of 10 N and a heating rate of 50K/h, using a Ceast 6921 of

GmbH, Germany.

The Viact B is the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 mm² circular or square cross-section, under a 1000 gm load.

Long-term Heat-aging is determined according to ISO 4577, using an "Thermo UT6120" oven of Thermo Fisher Scientific Inc., Germany. A sample plate with the dimensions 150 mm x 90 mmx 3 mm is formed by injection moulding of the polypropylene composition (PC) and placed in the oven at 100 ℃ for 1000h. Subsequently the surface of the sample plate is evaluated on sight If no crazing, crumbling or discolouring can be identified on the surface of the sampleplate, it is evaluated as "pass" , otherwise it is evaluated as "not passed" .

Long-term Heat and Pressure Resistance is determined according to ISO 1167, wherein pipe and a joint of the pipe formed by a set of fittings (such as a set of three fittings, including one elongated pipe fitting with a screw thread on an external surface at thwo opposite ends thereof, and two elongated pipe fittings with a screw thread on an internal surface at one end thereof and a smaller diameter at the other end that matches the diameter of the pipe to be jointed, the fitting with the screw thread at two opposing ends locates at center of the joint and joins the other two fittings) are subjected to pressurized water at 100 ℃ and 13 bar for 1000 h. If no bursting, leakage, or cracking can be identified on the surface of the pipe fittings by naked eyes, it is evaluated as "pass" , and otherwise it is evaluated as "not passed" .

2. Examples

The present invention is illustrated by the following examples:

The inventive propylene composition IE1 and the inventive propylene composition IE2 are based on recipes as summarized in Table 1.

Table 1: Recipe of the inventive propylene composition IEs1-2

Example		IE1	IE2
Example		IE1	IE2	HPP-1	[wt％] *	56.35	66.35
PMP	[wt％] *	1.50	1.50	HPP-1	[wt％] *	56.35	66.35
PMP	[wt％] *	1.50	1.50	FB	[wt％] *	40.00	30.00

*rest to 100 wt. -％are additives in regular levels, including polymeric carrier material, antioxidants, and UV-stabilizer, such as 1, 3, 5-Tris (3’, 5’-di-tert. butyl-4’-hydroxybenzyl) -isocyanurat in form of the commercial antioxidant “Irganox 3114” of BASF, Germany, tris (2, 4-di-t-butylphenyl) phosphite in form of the commercial antioxidant “Irgafos 168 FF ” of BASF, Germany, n-hexadecyl-3, 5-di-t-butyl-4-hydroxybenzoate and bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) sebacate in form of the commercial light stabilizer composition “Cyabsorb UV-3808PP5” of Cytec (U.S.A. ) and in form of the heat stabilizing agent “DSTP” of BASF SE, Germany.

“PMP” is the commercial graft copolymer of polypropylene (functionalized and grafted with maleic anhydride) “TPPP8112” of BYK Co. Ltd, Germany, having a MFR2 (190 ℃) of 100 g/10min and a maleic anhydride content of 1.4％；

“FB” are the commercial glass fibers “ECS305K” of Chongqing Polycomp International Corp, China, having a fiber diameter of 13 μm and a fiber length of 4.5 mm；

“HPP-1” has a melt flow rate MFR₂ (230 ℃) of 8 g/10min and a flexural modulus of 2100 MPa and is prepared as follows:

The catalyst used in the polymerization processes has been produced as follows: First, 0.1 mol of MgCl₂ x 3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of –15℃ and 300 ml of cold TiCl₄ was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20 ℃. At this temperature, 0.02 mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135 ℃ during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl₄ was added and the temperature was kept at 135 ℃ for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80 ℃. Then, the solid catalyst component was filtered and dried.

Catalyst and its preparation concept is described in general e.g. in patent publications EP491566, EP591224 and EP586390. The catalyst was prepolymerized with vinyl cyclohexane in an amount to achieve a concentration of 200 ppm poly (vinyl cyclohexane) (PVCH) in the final polymer (see EP 1183307 A1) . As co-catalyst triethyl aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane (D-donor) was used.

Table 2: Preparation of propylene homopolymer (HPP-1)

Parameter	Unit	HPP-1
Parameter	Unit	HPP-1	Loop
C2	[wt-％]	0	Loop
C2	[wt-％]	0	XCS	[wt. -％]	1.0
MFR₂ (230 ℃, 2.16 kg)	[g/10min]	1.5	XCS	[wt. -％]	1.0
MFR₂ (230 ℃, 2.16 kg)	[g/10min]	1.5	Split	[wt. -％]	50.0
GPR1			Split	[wt. -％]	50.0
GPR1			C2	[wt-％]	0
XCS	[wt. -％]	1.0	C2	[wt-％]	0
XCS	[wt. -％]	1.0	MFR	[g/10min]	8
Split	[wt. -％]	50.0	MFR	[g/10min]	8

Table 3: Properties of the inventive propylene compositions IE1 and IE2 and comparative propylene composition CE1

Example	Unit	IE1	IE2	CE1
Example	Unit	IE1	IE2	CE1	MFR₂ (230 ℃, 2.16 kg)	[g/10min]	3.50	3.00	1.7
Flexural Modulus	[MPa]	9000	6900	1200	MFR₂ (230 ℃, 2.16 kg)	[g/10min]	3.50	3.00	1.7
Flexural Modulus	[MPa]	9000	6900	1200	Izod NIS	[kJ/m²]	12.5	10.5	10
Vicat B	[℃]	165	166	55	Izod NIS	[kJ/m²]	12.5	10.5	10
Vicat B	[℃]	165	166	55	HDT	[℃]	155	153	50
Long-term Heat –aging (100 ℃, 1000h)		Pass	Pass	Not Passed*	HDT	[℃]	155	153	50

* crazing and crumbling

The inventive propylene compositions IE1 and IE2 are produced by melt blending. The inventive polypropylene compositions are based on the recipe summarized in Tables 1 and are prepared by using a Coperion STS-35 twin-screw extruder (available from Coperion (Nanjing) Corporation, China with a diameter of 35 mm. The twin-screw extruder runs at an average screw speed of 400 rpm with a temperature profile of zones from 180-230 ℃. It has a L/D of 44. The temperature of each zone, the throughput and the screw speed of the extruder for preparing the compositions of inventive examples IE1 and IE2 are listed in Table 4.

The temperature of each zone, throughput and screw speed of the extruder are initiative parameters, and are set on control panel of the extruder. Melt temperature (temperature of the melt in the die) and torque of the extruder are passive parameters shown on control panel of the extruder. A vacuum pump is located in zone 9 and generates a vacuum of -0.01 MPa inside the extruder.

Table 4: Extruder conditions for preparing the inventive compositions IE1 and IE2

Process condition	Unit	IE1	IE2
Process condition	Unit	IE1	IE2	Zone 1 (feeding opening)	[℃]	RT	RT
Zone2	[℃]	200	200	Zone 1 (feeding opening)	[℃]	RT	RT
Zone2	[℃]	200	200	Zone 3	[℃]	220	210
Zone 4	[℃]	220	210	Zone 3	[℃]	220	210
Zone 4	[℃]	220	210	Zone 5	[℃]	220	210
Zone 6	[℃]	225	215	Zone 5	[℃]	220	210
Zone 6	[℃]	225	215	Zone 7	[℃]	230	220
Zone 8	[℃]	230	220	Zone 7	[℃]	230	220
Zone 8	[℃]	230	220	Zone 9	[℃]	230	220
Zone 10	[℃]	230	220	Zone 9	[℃]	230	220
Zone 10	[℃]	230	220	Zone 11	[℃]	220	215
Die	[℃]	215	210	Zone 11	[℃]	220	215
Die	[℃]	215	210	Melt Temp.	[℃]	220	210
Throughput	[kg/hour]	60	60	Melt Temp.	[℃]	220	210
Throughput	[kg/hour]	60	60	Screw Speed	[rpm]	580	580
Vacuum	[MPa]	-0.01	-0.01	Screw Speed	[rpm]	580	580

As comparison, the commercial polypropylene copolymer compound

J340 of Hyosung Corp, Korea, i.e. CE1, is applied.

J340 of Hyosung Corp, Korea is used to prepare fittings of a pipe.

It can be seen that the inventive composition IE1 and IE2 have a significantly improved Flexural Modulus, Heat Deformation Temperature, Vicat Softening Temperature Vicat B, and Long-term Heat-aging as compared to the commercial polypropylene copolymer compound “J340” . The inventive compositions IE1 and IE2 can be applied to prepare pipe fitting with improved deformation and crack resistance at elevated temperatures and pressures.

In addition, pipe fittings are prepared from the inventive composition IE1, the inventive composition IE2 and the comparative composition CE1 by injection moulding, using the injection moulding device “Haitian” , commercially available from Haitian Plastic Machinery Corp. Ningpo, China.

A set of pipe fittings are prepared thereby, which comprise a first elongated pipe fitting with a screw thread on an external surface at two opposite ends of the elongated pipe fitting, asecond elongated pipe fitting with a screw thread on an internal surface at one end of the elongated pipe fitting and an a smaller diameter at the other end of the elongated pipe fitting that matches the diameter of the pipe to be jointed, and third elongated pipe fitting with a screw thread on an internal surface at one end of the elongated pipe fitting and an a smaller diameter at the other end of the elongated pipe fitting that matches the diameter of the pipe to be jointed. The first pipe fitting is joined with the second pipe fitting and the third pipe fitting, thereby forming the joint of the pipe.

The process conditions of the injection moulding device used for the preparation of the pipe fittings consisting of the inventive composition IE1, the inventive composition IE2 or the comparative composition CE1 are listed in Table 5, properties of the pipe fittings and joint thereof are listed in Table 6.

Table 5: Injection moulding device conditions for preparing pipe fittings consisting of composition IE1 and IE2

Process condition	Unit	IE1	IE2
Process condition	Unit	IE1	IE2	Zone 1	[℃]	180	180
Zone2	[℃]	210	205	Zone 1	[℃]	180	180
Zone2	[℃]	210	205	Zone 3	[℃]	220	215
Zone 4	[℃]	220	215	Zone 3	[℃]	220	215
Zone 4	[℃]	220	215	Nozzle	[℃]	200	195
Injection Pressure	[bar]	45	40	Nozzle	[℃]	200	195
Injection Pressure	[bar]	45	40	Holding Pressure	[bar]	48	43

Table 6: Long-term Heat and Pressure Resistance of pipe fittings consisting of composition IE1, IE2 or CE1 and joint of the fittings

Claims

Pipe comprising a polypropylene composition (PC) comprising

(i)propylene homopolymer (HPP-1) having an MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 in the range of 2 to 100 g/10 min, ；

(ii)polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min, and

(iii)fibers (FB) .
Pipe according to claim 1, wherein

(a)the weight ratio between the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) [ (HPP-1) / (PMP) ] is in the range of 300 to 8, based on the weight of the polypropylene composition (PC) ,

and/or

(b)the weight ratio between the propylene homopolymer (HPP-1) and the fibers (FB) [wt. -％ (HPP-1) /wt. -％ (FB) ] is in the range of 5.5 to 0.5, based on the weight of the polypropylene composition (PC) .
Pipe comprising a polypropylene composition (PC) consisting of

(i)propylene homopolymer (HPP-1) having a MFR₂ (230 ℃, 2, 16 kg) measured according to ISO 1133 in the range of 2 to 100 g/10 min, ；

(ii)polar modified polypropylene (PMP) having an MFR₂ (190 ℃, 2, 16 kg) measured according to ISO 1133 of at least 50 g/10 min,

(iii)fibers (FB) , and

(iv)additives (AD) .
Pipe according to claim 3, wherein

(a)the weight ratio between the propylene homopolymer (HPP-1) and the polar modified polypropylene (PMP) [ (HPP-1) / (PMP) ] is in the range of 300 to 8, based on the weight of the polypropylene composition (PC) ,

and/or

(b)the weight ratio between the propylene homopolymer (HPP-1) and the fibers (FB) [ (HPP-1) / (FB) ] is in the range of 5.5 to 0.5, based on the weight of the polypropylene composition (PC) ,

and/or

(c)the weight ratio between the propylene homopolymer (HPP-1) and the additives (AD) [ (HPP-1) / (AD) ] is in the range of 120 to 4, based on the weight of the polypropylene composition (PC) .
Pipe according to any of one of the previous claims, wherein

(a)the propylene homopolymer (HPP-1) comprises a first polypropylene fraction (HPP-1a) and a second polypropylene fraction (HPP-1b) and wherein first polypropylene fraction (HPP-1a) has a different MFR₂ compared to the a second polypropylene fraction (HPP-1b) .
Pipe according to claim 5, wherein the ratio of the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the propylene homopolymer (HPP-1) to the MFR₂ (230℃, 2.16 kg load) , measured according to ISO 1133, of the first polypropylene fraction (HPP-1a) [MFR₂ (HPP-1) /MFR₂ (HPP-1a) ] is in the range of 1.0 to 30.
Pipe according to any of one ofthe previous claims, wherein the polypropylene composition (PC) has a flexural modulus of at least 5000 MPa.
Pipe according to any of one of the previous claims, wherein the polypropylene composition (PC) has a Vicat Softening Temperature Vicat B of at least 100 ℃.
Pipe according to any of one of the previous claims, wherein the propylene homopolymer (HPP-1) is nucleated， preferably α-nucleated.
Pipe according to any of one of the previous claims, wherein the propylene homopolymer (HPP-1) has a flexural modulus of at least 1600 MPa.
Pipe according to any of one of the previous claims, wherein the polar modified polypropylene (PMP) comprises polar groups in an amount of at least 0.5 wt. -％.
Pipe according to any of one of the previous claims, wherein the fibers (FB) are selected from the group consisting of glass fibers, ceramic fibers, graphite fibers and mixtures thereof.
Pipe according to any of one of the previous claims, wherein the pipe is a pipe fitting.
Process for the preparation of a pipe according to any of the previous claims, comprising the steps of

(i) providing polymer composition (PC)

(ii) injection molding of the polymer composition (PC) to form a pipe.
Use of the polypropylene composition (PC) according to any of the previous claims in a pipe to improve the heat and/or pressure resistance.