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.
|Published (Last):||24 April 2004|
|PDF File Size:||2.54 Mb|
|ePub File Size:||3.45 Mb|
|Price:||Free* [*Free Regsitration Required]|
Audio and video engineering For those embodiments where the polypropylene composition comprises an alpha-nucleating agent selected from the group consisting of vinylcycloalkane polymers and vinylalkane polymers, preferably poly-vinylcyclohexane pVCHthe typical concentration of vinyl cyclo alkane polymer in the polypropylene composition is from 0. Xylene cold solubles were determined at 23 0 C according ISO The welding joint quality would be influenced negatively.
Compounding The heterophasic propylene copolymer, additives and optional alpha-nucleating agent can be mixed, in particular melt blended, according to any conventional procedure known in the art. This document is herewith included by reference. ZN from Basell, may be used for producing the heterophasic propylene polymers of the invention.
PROCESS FOR BUTT WELDING OF POLYPROPYLENE – BOREALIS AG
Among these, polyethylene and polypropylene are widely used for cold and hot water pipes, pressure and non-pressure pipes, drainage pipes and sewerage. Asakura, Polymer 29 Petroleum and related technologies The welded joints of pipe sections must be able to withstand a certain mechanical bending stress upon installation.
Mechanical systems and components for general use According to the present invention, the MFR A of the propylene homopolymer is from 0. Reference is made in this context to B. According to an embodiment, a catalyst to be used in the invention is disclosed in EP which discloses a method for preparing a procatalyst composition from magnesium dichloride, a titanium compound, a lower alcohol and an ester of phthalic acid containing at least five carbon atoms.
Most preferred are polypropylene compositions containing as alpha-nucleating agent poly- vinylcyclohexane pVCHtalc or mixtures thereof.
For those embodiments where the alpha-nucleating agent is not a polymeric nucleating agent, the nucleating agent is typically present in the polypropylene composition in an amount of from 0. Smaller amounts of alpha-nucleating agent than 0.
Preferably the total MFR of the polypropylene composition is from 0. The propylene homopolymer can be unimodal or multimodal, like bimodal in view of dvss molecular weight distribution.
As described above, after the polymerisation of the heterophasic propylene copolymer the mixing with additives and optional alpha-nucleating agent follows.
However, it is preferred to have the sequence i to iii as stated above. The polypropylene compositions of the present invention are preferably produced by combining the heterophasic propylene copolymer and optional alpha-nucleating agents and any additives, like pigments, stabilisers, processing aids, etc.
The catalyst component of the catalyst system primarily containing magnesium, titanium, halogen and an internal donor. However, more desirably, the heterophasic propylene copolymer is produced in a multistage process and subsequently mixed with additives and optional alpha-nucleating agent. 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 expression propylene homopolymer used in the instant invention relates to a polypropylene that consists substantially, i. Thus in a preferred embodiment the polypropylene homopolymer comprises two fractions which differ in their molecular weight, wherein the first fraction having the lower molecular weight is present from 40 to 60 wt.
Search Expert Search Quick Search. We wish you a pleasant end-of-year holiday.