Abstract:
A pipe or hose composed of a polyamide moulding composition whose molecular weight has been increased by condensation, via addition of a compound having at least two carbonate units in a quantitative proportion of from 0.005 to 10% by weight, based on polyamide, where a) a starting polyamide moulding composition was provided, b) a mixture of the starting polyamide moulding composition and of the compound having at least two carbonate units was produced, c) the premix was, if desired, stored and/or transported, and d) the premix was then processed to give the moulding, this step being the first in which the increase of molecular weight by condensation occurred, the moulding being a pipe or hose whose external diameter is at least 25 mm is used as inliner for a pipeline.
Abstract:
A process for condensing polyamides to increase their molecular weight, using a compound having at least two carbonate units comprises using a polyamide which, as a result of its preparation, comprises from 5 to 500 ppm of phosphorus in the form of an acidic compound, and adding, to the polyamide, from 0.001 to 10% by weight of a salt of a weak acid, thus eliminating the inhibiting action of the phosphorus compound.
Abstract:
The invention relates to a flexible pipe having a multi-layered structure comprising unbonded layers, comprising an inner lining having the following layer arrangement: a) an innermost layer made of a fluoropolymer molding compound, b) an intermediate layer made of a molding compound on the basis of an olefinic polymer, which is selected from the group consisting of polyethylene, isotactic polypropylene, syndiotactic polypropylene and syndiotactic polystyrene, c) an outer layer made of a polyamide molding compound, wherein the layer made of a polyamide molding compound is particularly efficiently protected against hydrolysis. The pipe is thus particularly suited for offshore applications in oil or gas production.
Abstract:
A process for the production of a pipe comprising: an interior surface having a shape; and a thermoplastic inliner is provided. The process comprises: introducing the thermoplastic inliner into the interior of the pipe; heating the pipe from the outside to a temperature higher than a crystallite melting point (Tm) of a moulding composition of an exterior surface of the inliner; expanding the inliner radially in the pipe so that an exterior surface of the inliner assumes the shape of the interior surface of the pipe; and cooling the inliner; wherein a cross section of the inliner is optionally reduced through exposure to an exterior force prior to being introduced into the pipe. Relative movements between carrier pipe and inliner are thus prevented; the risk of collapse of the inliner is moreover low. The pipe is used for the production of a laid pipeline.
Abstract:
A pipe or pipeline for use in the oil and gas industry for conveying lines, collection pipelines and transport pipelines with reduced operating risk and increased lifetime is provided. The pipe contains: a) an external reinforcement layer and b) an internal liner which comprises securely bonded to one another: I) a layer made of a thermoplastic moulding composition selected from a polyolefin moulding composition and a fluoropolymer moulding composition and II) a layer made of a polyamide moulding composition, wherein not only the polyamide moulding composition but also the moulding composition of the layer according to I) in essence comprises no blend component which is composed of another polymer and which has disperse distribution in the moulding composition.
Abstract:
A pipe or hose composed of a polyamide moulding composition whose molecular weight has been increased by condensation, via addition of a compound having at least two carbonate units in a quantitative proportion of from 0.005 to 10% by weight, based on polyamide, where a) a starting polyamide moulding composition was provided, b) a mixture of the starting polyamide moulding composition and of the compound having at least two carbonate units was produced, c) the premix was, if desired, stored and/or transported, and d) the premix was then processed to give the moulding, this step being the first in which the increase of molecular weight by condensation occurred, the moulding being a pipe or hose whose external diameter is at least 25 mmis used as inliner for a pipeline.
Abstract:
A metal conduit pipe, which is covered with an extruded layer made of polyamide moulding compound, is used to produce a duct laid in water, wherein in the course of laying the duct, the coating is exposed to a shearing pressure load and/or a bending load due to laying method selected.
Abstract:
A pipe, which comprises the following layers: I. an exterior layer composed of a moulding composition which comprises at least 40% by weight of a polyamide whose monomer units contain, on average, at least 8 carbon atoms, III. an intermediate layer composed of a moulding composition which comprises the following components: a) from 70 to 99% by weight of polyamide, selected from PA6, PA66, PA6/66 and mixtures thereof and b) from 1 to 30% by weight of plasticizer, where the moulding composition comprises no impact modifier, and V. an interior layer composed of a moulding composition which comprises at least 40% by weight of a polyamide whose monomer units contain, on average, at least 8 carbon atoms, where a) the exterior diameter of the pipe is in the range from 6 to 20 mm, b) the wall thickness is in the range from 1.0 to 2.0 mm and c) the thickness of the polypropylene layer is from 25 to 75% of the wall thickness, is used as air-brake line which can be produced at low cost and which has high bursting strength and good low-temperature impact resistance.
Abstract:
A pipe includes an outer layer composed of a molding composition which comprises at least 40% by weight of a polyamide whose monomer units contain an average of at least 8 carbon atoms, and a layer composed of a polypropylene molding composition. An outer diameter of the pipe is in a range from 6 to 20 mm, a wall thickness of the pipe is in a range from 1.0 to 2.0 mm, and a thickness of the polypropylene layer is from 25 to 75% of the wall thickness. The pipe can be used as an air-brake line that can be produced at low cost, has high bursting strength, and has good low-temperature impact resistance.
Abstract:
A process for producing moldings with condensing-up of a polyamide molding composition whose polyamide component contains, as a result of the method of preparation, at least 5 ppm of phosphorus in the form of an acidic compound by means of a compound having at least two carbonate units, wherein a) from 0.001 to 10% by weight, based on the polyamide, of a salt of a weak acid is added to the polyamide molding composition prior to compounding or during compounding, b) a mixture of the finished composition and the compound having at least two carbonate units is prepared, c) the mixture is, if appropriate, stored and/or transported and d) the mixture is subsequently processed to produce the molding, with the condensing-up occurring only in this step, effects a significant increase in the melt stiffness combined with moderate processing presssures, which considerably simplifies, in particular, the production of hollow bodies and hollow profiles having large diameters.