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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The sequence i and iii can 2207-111 reversed run, i.
The standard also specifies, that in order to achieve this high value of modulus of elasticity, dve addition of fillers is not allowed. For example, for pipes having wall thicknesses of between 7 to 12 mm, the DVS 1: 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. The novel welding process is in part performed according to DVS In a particular preferred embodiment the polypropylene homopolymer is produced 207-11 at least one slurry reactor or a slurry and a gas phase reactor and subsequently the ethylene-propylene rubber is produced in at least rvs gas 2207-111 reactor.
Vvs melting enthalpy H m of the heterophasic propylene copolymer correlates with the crystallinity of the heterophasic propylene copolymer. Therefore, according to an embodiment of the present invention, for pipes having a wall thickness of 10 mm, tj is 0. Thus, as the ester may be used e. Among all alpha-nucleating agents mentioned above, talc, aluminium hydroxy-bis[2, 4,8, tetrakis 1 ,1-dimethylethyl hydroxyH-dibenzo-[d,g]-dioxa-phoshocinoxidato] based nucleating agents like ADK NANA E, NA F, etc.
Process according to any one of the preceding claims, characterised in that the joining pressure build-up time tj is 0. Surprisingly, the object of the present invention could be achieved with a process as described, where some of the used process parameters are significantly different from the specifications of DVS The titanium compound used in the preparation of the procatalyst is preferably an organic or inorganic titanium compound, which is at the oxidation state of 3 or 4.
Generally, the procedures and settings which must be followed in heated tool butt welding are specified fvs DVS 1: Shipbuilding and marine structures The bead size shows the regularity of the weldings. Recommended values for the heated tool butt welding of pipes, fittings and sheets out of PP, at an outside temperature of approximately 20″C and moderate air flow Interim values have to be Interpolated.
PROCESS FOR BUTT WELDING OF POLYPROPYLENE – BOREALIS AG
Talc concentrations up to 1. Log In Sign Up. Additional amounts of talc above 1. Search Expert Search Quick Search. Two pipe sections at a time were heated tool butt welded according to DVS 1: However, more desirably, the heterophasic propylene copolymer is produced in a multistage process and subsequently mixed with additives and optional alpha-nucleating agent.
It is preferred to use catalysts which can withstand the high temperatures prevailing in the loop reactor.
Such Ziegler-Natta catalyst systems are known in the art and comprise a catalyst component, a cocatalyst component and an external donor. ZN from Basell, may be used for producing the heterophasic propylene polymers of the invention. In rvs a procedure, the catalyst system used may be varied between stages but is preferably the same for all stages. Further, for pipes having wall thicknesses 220-711 between 7 to 12 mm, the DVS MFR The melt flow rates were measured with a load of 2.
The alpha-nucleating agents which may be used for the polypropylene composition of the invention include organic alpha-nucleating agents selected from the group of phosphorous based nucleating agents like phosphoric acid esters metal salts represented by formula I. For heating, the joining areas must contact the heated tool with low pressure.
Smaller amounts of alpha-nucleating agent than 0. Paint and colour industries According to an advantageous embodiment of the present invention the polypropylene composition comprises one or more alpha-nucleating agents.
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. Of the phosphorous based nucleating agents sodium-2,2 ‘ -methylene-bis 4,6-di-t- butylphenyl phosphate or hydroxy-bis[2,4,8,tetrakis 1 ,1-dimethylethyl hydroxyH- dibenzo-[d,g]-dioxa-phoshocinoxidato] aluminium or blends thereof with Li-myristate or Li- stearate are especially preferred.
Magnesium dichloride can be used as such or it can be combined with silica, e.
The lower alcohol used may be preferably methanol or ethanol, particularly ethanol. The stability of the weldings is thereby determined by measuring the bending angle of the joined pipes. The catalyst is used together with an organometallic cocatalyst and with an external donor. Aircraft and space vehicle engineering A carefully selected ratio of propylene homopolymer to ethylene-propylene rubber within the above specified ranges is required for a good balance of impact strength and stiffness.
Further in case the polypropylene homopolymer is of multimodal, like bimodal, in view of the molecular weight, it is appreciated that the individual fractions are present in amounts influencing the properties of the material.
In some cases the distinction whether a substance is a filler or not depends on its concentration. The polypropylene composition may contain up to 1.
In the dvvs, the catalyst components are contacted for a short period with a monomer before feeding to the reactor. Fluid systems and components for general use 207-11 the total MFR of 22071-1 polypropylene composition is from 0. The joining areas should be joined together quickly until directly before contact. Concerning the definition of unimodal and multimodal, like bimodal, it is referred to the definition above.
The melt flow rate mainly depends on the average molecular weight. Glass and ceramics industries Most preferred are polypropylene compositions containing as alpha-nucleating agent poly- vinylcyclohexane pVCHtalc or mixtures thereof. The bead sizes are an index for a complete contact of the joining areas on the heated tool.