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):||28 November 2010|
|PDF File Size:||1.41 Mb|
|ePub File Size:||17.37 Mb|
|Price:||Free* [*Free Regsitration Required]|
It is also appreciated that according to the present invention, the polypropylene pipes consist of a polypropylene composition comprising a heterophasic propylene copolymer consisting of. The stability of the weldings is thereby determined by measuring the bending angle of the joined pipes.
Further, the DVS The alkoxy 2207-11 of the phthalic acid ester used comprises at least five carbon atoms, preferably at least eight carbon atoms. Xylene cold solubles were determined at 23 0 C according ISO Generally, the external donor has the formula wherein.
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 two subsequent reactors producing ethylene-propylene rubber.
The requirements which are specified in EN 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 227-11.
The novel process results in an improved stability of the welding joints. The pressure is reduced to nearly zero 0. The alignment is finished when the bead heights have reached the mentioned values in table 2, column 2 on the total pipe circumference resp.
PROCESS FOR BUTT WELDING OF POLYPROPYLENE – BOREALIS AG
In such a procedure, the catalyst system used may be varied between stages but is preferably the same for all stages. A second group of phosphorous based nucleating agents which may be used fort he present 2027-11 includes for example hydroxy-bis[2,4,8,tetrakis 1 ,1-dimethylethyl hydroxy- 12H-dibenzo-[d,g]-dioxa-phoshocinoxidato] aluminium CAS and blends thereof with Li-myristate or Li-stearate.
This is even more surprising since relevant publications stress the fact, that deviating from the standard is not permitted.
Accordingly it is appreciated that the polypropylene homopolymer has a rather high isotacticity, measured as pentad concentration [mmmm], i. It is preferred to use catalysts which can withstand the high temperatures prevailing in the loop reactor.
It is even further preferred, that the polypropylene composition of the invention comprises an alpha-nucleating agent selected from the group of polymeric nucleating agents, selected from the group consisting of vinylcycloalkane polymers and vinylalkane polymers, preferably poly-vinylcyclohexane pVCHand aluminium hydroxy-bis[2,4,8,tetrakis 1 ,1- dimethylethyl hydroxyH-dibenzo-[d,g]-dioxa-phoshocinoxidato] based nucleating agents e.
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. In the following a preferred process is described in more detail: Rvs other transition metal compounds, such as vanadium, zirconium, chromium, molybdenum and tungsten compounds can be mixed with the titanium compound.
Chinacridon pigments or earth-alkali metal salts of dicarboxylic acids, e. This object could be achieved with a process of forming a weld between abutting ends of two polypropylene pipes to 227-11 joined, which comprises.
Textile and leather technology These methods are described in greater detail in e.
The molar ratio of phthalic acid ester and magnesium halide is preferably about 0. Flexural Modulus of the composition is MPa. Shipbuilding and marine structures Melt mixing devices suited for this process are discontinuous and continuous kneaders, twin screw extruders and single screw extruders with special mixing sections and co-kneaders.
Paint and colour industries The ethylene-propylene rubber may be dve with the polypropylene homopolymer after their polymerizations, and are subsequently mixed with any additives and optional alpha-nucleating agent. According to the invention, such catalysts are typically introduced into the first reactor only.
The heterophasic propylene copolymer was blended with the following additives: The heated tool should be withdrawn in such a way that the heated joining areas are neither damaged nor contaminated.
All the remaining parameters and process settings as specified in DVS Process according to any one of the preceding claims, characterised in that the propylene homopolymer A has an isotacticity measured as concentration of [mmmm] pentads of.
The organoaluminium compound is preferably selected from the group consisting of trialkyl aluminium, dialkyl aluminium chloride and alkyl aluminium sesquichloride. Health care technology It is further appreciated that the propylene homopolymer has a low medium flow rate MFRi.
Materials handling equipment dv 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 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. Such polypropylenes are characterized by rather high melt strength. A still further group of suitable nucleating agents includes resin acids also called rosin acids and esters and metal salts of resin acids, in 22071-1 sodium, calcium and magnesium salts.
This low polymerization temperature may put a practical limit on the heat removal dvss of the loop reactor.