Abstract:
A process for producing moldings with condensing-up of a polyamide molding composition by means of a compound having at least two carbonate units, wherein a) a polyamide molding composition is made available, b) a mixture of the polyamide molding 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, and the molding is a hollow body or hollow profile having an external diameter of at least 30 mm and a wall thickness of at least 1 mm, effects a significant increase in the melt stiffness combined with moderate processing presssures, which considerably simplifies the production of these moldings.
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 molding 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 molding composition selected from a polyolefin molding composition and a fluoropolymer molding composition and II) a layer made of a polyamide molding composition, wherein not only the polyamide molding composition but also the molding 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 molding composition.
Abstract:
A flexible pipe of multilayer structure which comprises the following layers, from the inside to the outside: an interior lining; an inner reinforcement layer; a layer of molded electrically conductive plastic; an outer reinforcement layer; and an exterior sheath. The electrically conductive plastic layer is in electrical contact with the two reinforcement layers, and the two reinforcement layers can be connected to a source of electrical current. It is thus possible to achieve efficient heating of the pipe, and it can therefore be used for conveying oil in cold regions.
Abstract:
A flexible pipe which can be heated efficiently, and may therefore be used for conveying oil in cold regions, is provided. The pipe comprises in order from inside to outside: an interior lining; a wound tape; and at least one reinforcement layer. The wound tape contains a first exterior layer of a plastics molding composition that is not electrically conductive; an intermediate layer of an electrically conductive plastics molding composition; and a second exterior layer of a plastics molding composition that is not electrically conductive. A volume resistivity to IEC 60093 of the intermediate layer is in the range from 10−3 to 1010 Ωm, and the intermediate layer comprises at least two metallic conductors embedded into the plastic molding composition along an entire length of the tape in such a way that, the two conductors do not touch one another.
Abstract:
A molding compound for joining two moldings each made of a PA11 and/or PA12 molding compound contains at least 50% by weight of a polyamide component so chosen that it is preparable from linear aliphatic diamines and dicarboxylic acids and/or lactams or ω-aminocarboxylic acids, there being 11 to 12 carbon atoms present per carboxamide group in the repeating units, and, furthermore, this polyamide component containing not more than 80% by weight of either one of the polyamides PA11 and PA12. With this compound a firm weld is obtained both to a PA11 molding and to a PA12 molding.
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 producing hydrolysis-resistant mouldings with geometries having large dimensions by cumulative condensation of a polyamide moulding composition, is provided. The process includes mixing a polyamide moulding composition of a polyamide having at least 50% of amino end groups with 0.1 to 5% by weight, based on the polyamide moulding composition, of an oligo- or polycarbodiimide. The mixture is subsequently processed to give the moulding, wherein cumulative condensation is obtained during the processing of the moulding.
Abstract:
In a flexible pipe of multilayer structure with unbonded layers, where the pipe has an interior lining which comprises the following layers: a) at least one layer of which the material has been selected from the group of polyolefin moulding composition, polyamide moulding composition and polyvinylidene fluoride moulding composition, and also b) at least one layer of which the material is composed of a moulding composition based on a polymer selected from the group of polyarylene ether ketone, polyphenylene sulphide, polyarylene ether ketone/polyphenylene sulphide blend, polyphenyl sulphone and polyalkylene naphthalate, the exterior reinforcement has particularly efficient protection from corrosion due to aggressive constituents which diffuse outwards from the fluid conveyed. The pipe therefore has particular suitability for offshore applications in the production of oil or of gas.
Abstract:
The invention relates to a flexible tube of multilayer construction having unbonded layers, wherein at least one layer is formed in that a tape made of a plastic molding compound is spirally wound about a further inner layer, wherein the upper and lower layers of the tape are simultaneously or subsequently welded to each other at overlapping regions. The tube is particularly suitable for offshore application in oil and gas extraction