Melabar Accordingly it is appreciated that the polypropylene homopolymer has a rather high isotacticity, measured as pentad concentration [mmmm], i. The conventional Ziegler-Natta catalysts for isotactic polymerization of propylene generally have an operating temperature limit of around 80 0 C, above which they either become deactivated or lose their stereo-selectivity. 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. Process according to claim 8, wherein the pipes to be joined have a wall thickness of 10 mm and the heating-up time is from 70 — s. The content of XCS of the heterophasic propylene copolymer correlates closely with the amount of ethylene-propylene rubber.
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Kisar This fact is visible on the kind of beads. Preferably the total MFR of the polypropylene composition is from 0. Search Expert Search Quick Search. Petroleum and related technologies Alert me in case of modifications on this product contact us. As will be explained below, the propylene homopolymer can be produced in a single step or in a sequential step process, using reactors in serial configuration and which can be operated at different reaction conditions.
Most preferred are polypropylene compositions containing as alpha-nucleating agent poly- vinylcyclohexane pVCHtalc or mixtures thereof. Before installation a pipe system, individual pipe sections are joined to each other, generally by welding. Concerning the definition of unimodal and multimodal, like bimodal, it is referred to the definition above. As catalyst a commercially available Ziegler-Natta catalyst which was prepolymerised with poly-vinylcyclohexane was used together with dicyclopentyl dimethoxy silane DCPDMS as external donor and triethylaluminium as cocatalyst.
Like the polypropylene homopolymer, the ethylene-propylene rubber can be unimodal or multimodal, like bimodal. Two pipe sections at a time were heated tool butt welded according to DVS 1: However, according to the invention, the temperature TW is from — 0 C. For pipes having a wall thickness of 10 mm this means an interpolated heating-up time t H of s. For heating, the joining areas must contact the heated tool with low pressure. Preferably the polypropylene composition comprises 0.
DVS However, more desirably, the heterophasic propylene copolymer is produced in a multistage process and subsequently mixed with additives and optional alpha-nucleating For example, the ethylene-propylene rubber may also comprise a portion with very high ethylene concentration, which is crystalline and therefore insoluble in cold xylene.
As a consequence, each fraction prepared in a specific reactor can have its own molecular weight distribution. Particularly preferred are the titanium halides, especially titanium tetrachloride. Shipping Delivery Order tracking Returns. 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.
The alkoxy group of the phthalic acid ester used comprises at least five carbon atoms, preferably at least eight carbon atoms. Thus, as vvs ester may be used e. The requirements which are specified in EN The welding joint quality would be influenced negatively. 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, tungsten compounds and rare earth metal compounds, titanium trichloride and titanium tetrachloride being particularly preferred.
Talc, for example, is used as alpha-nucleating agent in concentrations of from 0. As a catalyst for the preparation of the heterophasic propylene copolymer preferably a Ziegler-Natta catalyst system is used. Good processability must be ensured, while maintaining all other desired properties. A further suitable nucleating agent which can be used for dvx present invention is talc.
Chinacridon pigments or earth-alkali metal salts of dicarboxylic acids, e. One of the most widely implemented pipes in sewerage applications have a nominal wall thickness of 10 mm.
DVS 2207-11 PDF
This fact is visible on the kind of beads. Reference is made in this context to B. Preferably the total MFR of the polypropylene composition is from 0. Materials handling equipment The residence time must be chosen such that a sufficiently high degree of homogenisation is achieved.
Arashidal 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.