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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Xylene solubles are defined as the percent by weight that stays in solution after the polymer sample is dissolved in hot xylene and the solution is allowed to cool to 23 0 C. 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.
It was surprisingly possible to achieve significant improvements in the stability of welding joints for pipes from PP-HM polypropylene by deviating from the settings as prescribed in the standard and by modifying these settings as claimed in the present invention.
The changeover time should be as short as possible see table 2, column 4as otherwise the plastified areas will cool down. Process for butt welding of polypropylene.
The content of XCS of the heterophasic propylene copolymer correlates closely with the amount of ethylene-propylene rubber. Thus, as the ester may xvs used e.
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.
Further, the DVS Process according to any one of the preceding claims, characterised in that for pipes having a wall thickness of 10 mm, tj is 0. Additionally it is appreciated that the polypropylene homopolymer is not chemically modified as it is known for instance from high melt strength polymers HMS-polymer. The components of the catalyst can be fed into the reactor separately or simultaneously or the components of the catalyst system can be precontacted prior to the reactor.
This ethylene content is adjusted by the ratio between propylene homopolymer and ethylene- propylene rubber and by the ethylene content of the ethylene-propylene rubber. Process stages of heated tool butt welding. The MFR A of the propylene homopolymer is selected such that – together with the other components of the polypropylene composition – the total MFR of the polypropylene composition is within the range which is required for the intended application and which is also specified in EN After heating, the joining areas are to be detached from the heated tool.
The comonomer feeds into the various reactors may be adapted to produce the heterophasic propylene copolymer with the desired properties and the amounts of ethylene will be readily determined by the person skilled in the art. A number of welding techniques is used, including heated tool butt welding also called butt fusion weldingelectro fusion welding, heated tool socket welding, extrusion welding, hot gas welding. This low polymerization temperature may put a practical limit on the heat removal efficiency of the loop reactor.
The titanium compound usually is a halide or oxyhalide, an organic metal halide, or a purely metal organic compound in which only organic ligands have been attached to the transition metal.
With the exception of the heated tool temperature, the heating-up time and the joining pressure build-up time the parameters as specified in DVS 1: These methods are described in greater detail in e.
All the remaining 22077-11 and process settings as specified in DVS An increase in molecular weight means a decrease in the MFR-value.
Process according to any one of the 220-711 claims, characterised in that the joining pressure build-up time tj is 0. 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 polymer was mixed with the additives and nucleating agent in an intensive mixer Henschel mixer for 25 seconds. 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. The transition metal compound is selected from the group consisting of titanium compounds having an oxidation degree of 3 or 4, vanadium compounds, zirconium compounds, cobalt compounds, nickel compounds, dvss compounds and rare earth metal compounds, titanium trichloride and titanium tetrachloride being particularly preferred.
According to the invention, the total MFR of the polypropylene composition is from 0. The organoaluminium compound is preferably selected from the group consisting of trialkyl aluminium, dialkyl aluminium chloride and alkyl aluminium sesquichloride.
Textile and leather technology Accordingly in case of a bimodal system, in particular in view of the molecular weight, the split of the two fractions is roughly According to EN For heating, the joining areas must contact the heated tool with low pressure.
The catalyst preferably contains a transition metal compound as a procatalyst component. Such a polymer, produced in two or 22207-11 serial steps, is called bimodal or multimodal, depending on the number of steps.
PROCESS FOR BUTT WELDING OF POLYPROPYLENE – BOREALIS AG
Welding thermoplastic materials – Heated element 22007-11 of pipes, piping parts and panels made of PP. An organoaluminium compound is used as a cocatalyst.
Mechanical systems and components for general use The melting enthalpy H m of the heterophasic propylene copolymer correlates with the crystallinity of the heterophasic propylene copolymer. You have no items in your shopping cart.
Dfs expression propylene homopolymer used in the instant invention relates to a polypropylene that consists substantially, i.
The branching index g’ correlates with the amount of branches of a polymer. The method was calibrated by ethylene content data measured by 13 C-NMR. A second group of phosphorous based nucleating agents which may be used fort he present invention includes for example dva 1 ,1-dimethylethyl hydroxy- 12H-dibenzo-[d,g]-dioxa-phoshocinoxidato] aluminium CAS and blends thereof with Li-myristate or Li-stearate.
For example, the publication “Installing plastic pipes”, which is published by IPS Flow Systems, and which is available at www.