the German guideline DVS Part 11(1) are followed. (see Table 1 below). Process steps in butt welding according to DVS guidelines. Table 2. of the Technical Committee of the. German Welding Society – DVS. Page 2. DVS- Technical Codes and Bulletins .. DVS ()* Welding of. DVS-Technical codes and bulletins can be obtained from: DVS Media .. DVS ()* Welding of thermoplastics – Heated tool welding of pipes.

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In the following a preferred process is described in more detail: This low polymerization temperature may put a practical limit on the heat removal efficiency of the loop reactor. Two pipe sections at a time were heated tool butt welded according to DVS 1: A heterophasic propylene copolymer were produced in a two step process. One of the most widely implemented pipes in sewerage applications have a nominal wall thickness of 10 mm.

Also other transition metal compounds, such as vanadium, zirconium, chromium, molybdenum and tungsten compounds can be mixed with vds titanium compound. Magnesium dichloride can be used as such or it can be combined with silica, e.

After the joining, a regular double-bead must appear. It is further appreciated that the propylene homopolymer has a low medium flow rate MFRi.

Such Ziegler-Natta catalyst systems are known in the art and comprise a catalyst component, a cocatalyst component and 207-11 external donor. Welding thermoplastic materials – Heated element welding of pipes, piping parts and panels made of PP. Asakura, Polymer 29 A further suitable nucleating agent which can be used for the present invention is talc.

Process for butt welding of polypropylene The invention relates to a process for heated tool butt welding of polypropylene pipes. The melting enthalpy H m of the heterophasic propylene copolymer correlates with the crystallinity of the heterophasic propylene copolymer.


It is therefore the object of the present invention to provide a process for heated tool butt welding of polypropylene pipes, having an improved stability of the weldings.

In some cases the distinction whether a substance is a filler or not depends on its concentration.

An organoaluminium compound is used as a cocatalyst. The catalyst preferably contains a transition metal compound as a procatalyst component. Fillers further include glass powder, glass beads, fly ash powder, asbestos powder.

Thereby, a low g’-value is an indicator for xvs high branched polymer.

The alkoxy group of the phthalic acid ester used comprises at least five carbon atoms, preferably at least eight carbon atoms.

Object It is therefore the object of the present invention to provide a process for heated tool butt welding of polypropylene pipes, having an improved stability of the weldings. The melt flow rates were measured with a load of 2. Generally, the external donor has the formula wherein.

This document is herewith included by reference. In a preferred embodiment only propylene units in the propylene homopolymer are detectable. ZN from Basell, may be used for producing the heterophasic propylene polymers of the invention. According to the present invention, there is also provided a process for the manufacture of the polypropylene composition discussed above.

Optionally, the rubber also comprises some crystalline polyethylene. MFR The melt flow rates were measured with a load of 2. Especially preferably, dve prepolymerized heterogeneous catalyst is used. The standard also specifies, that in order to achieve this high value of modulus of elasticity, the addition of fillers is not allowed.

Accordingly it is appreciated that each of these fractions is at least present in an amount of 10 wt. The pressure is reduced to nearly zero 0.

  CAT 930G PDF

According to a specific embodiment, only three reactors are utilized with either two reactors producing homopolymer and the third reactor producing ethylene-propylene rubber or with one reactor producing homopolymer and dvz subsequent reactors producing ethylene-propylene rubber. For example, the publication “Installing plastic pipes”, which is published by IPS Flow Systems, and which is available at www.

DVS 2207-11:2017-02

In heated tool butt welding the welding areas are heated to the welding temperature by means of the heated tool and joined under pressure after removal of the heated tool. Accordingly the heterophasic propylene copolymer of the instant invention can be typically produced in a cascade of up to 4 reactors, where the first reactor is a liquid bulk reactor preferably of loop design, the second reactor is either a liquid bulk reactor preferably of loop design or a gas phase reactor and all subsequent reactors are gas phase reactors preferably of fluidized bed design.

Sometimes, the “heating-up time” is also just called “heating time”. According to 2207-1 invention, the total MFR of the polypropylene composition is from 0.


MFR A of homopolymer matrix 0. Process according to any one of the preceding claims, characterised in that the polypropylene composition comprises one or more alpha-nucleating agents. Description of heterophasic propylene copolymer A heterophasic propylene copolymer according to the invention has preferably a multiphase structure with a continuous propylene homopolymer matrix and inclusions of ethylene- propylene rubber comprising at least an amorphous elastomeric phase.

According to the invention, such catalysts 2207-1 typically introduced vvs the first reactor only.