Abstract:
Multilayer composites are obtained from a molding composition which contains the following components: a) 100 parts by weight of polyamide and b) from 0.005 to 10 parts by weight of a compound having at least two carbonate units by coextruding with a molding composition based on a high-melting-point polymer whose crystallite melting point Tm is at least 255° C. and/or whose glass transition temperature Tg is at least 180° C.
Abstract:
A moulding composition which comprises at least 50% by weight of the following constituents:a) from 0 to 99 parts by weight of polyamide, andb) from 1 to 100 parts by weight of polyamide elastomer, selected from the group of polyetheresteramide and polyetheramide,where the total of the parts by weight is 100 and where the moulding composition comprises from 0 to 9% by weight of plasticizer,is used for the production of a moulding for contact with a supercritical medium, and preferably for the production of an inner thermoplastics layer in a flexible pipe or rigid pipe, in which a supercritical medium is conveyed. Low or zero plasticizer content eliminates any significant occurrence of problems such as increased stiffness and longitudinal shrinkage.
Abstract:
A pipe includes an outer layer composed of a molding composition which includes 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 metallic pipe for contact with a hydrolyzing medium provides longer operating times and improved high temperature resistance. The pipe contains a layer of a polyamide moulding composition containing at least 50% by weight of polyamide content containing: I) 60 to 98 parts by weight of a polyamide which contains 10 to 70 meq/kg of a terminal carboxy group and has a relative solution viscosity ηrel of at least 1.90, and II) 2 to 40 parts by weight of a polyamine-polyamide graft copolymer produced from: a) 0.5 to 25% by weight, based on the entire monomer mixture, of a polyamine having at least 4 nitrogen atoms, and b) 75 to 99.5% by weight, based on the entire monomer mixture, of polyamide-forming monomers selected from lactams, ω-aminocarboxylic acids and/or equimolar combinations of diamine and dicarboxylic acid, with the proviso that the amino group concentration of the graft copolymer is in the range from 100 to 2500 meq/kg, wherein the sum of the parts by weight of I) and II) is 100.
Abstract:
A pipeline laid trenchlessly and/or without a sand bed is produced using a metallic conduit which is encased with an extruded layer of a polyamide molding material. In this way, the durability of the outer shell required for trenchless laying techniques without a sand bed is ensured.
Abstract:
A metallic pipe for contact with a hydrolyzing medium provides longer operating times and improved high temperature resistance. The pipe contains a layer of a polyamide moulding composition containing at least 50% by weight of polyamide content containing: I) 60 to 98 parts by weight of a polyamide which contains 10 to 70 meq/kg of a terminal carboxy group and has a relative solution viscosity ηrel of at least 1.90, and II) 2 to 40 parts by weight of a polyamine-polyamide graft copolymer produced from: a) 0.5 to 25% by weight, based on the entire monomer mixture, of a polyamine having at least 4 nitrogen atoms, and b) 75 to 99.5% by weight, based on the entire monomer mixture, of polyamide-forming monomers selected from lactams, ω-aminocarboxylic acids and/or equimolar combinations of diamine and dicarboxylic acid, with the proviso that the amino group concentration of the graft copolymer is in the range from 100 to 2500 meq/kg, wherein the sum of the parts by weight of I) and II) is 100.
Abstract:
A polyamide molding composition is condensed up in the melt by means of a masterbatch containing a compound having at least two carbonate units and also a polyetheramide in which at least 50% of the end groups are present as amino end groups, whereupon the melt mixture is discharged and solidified to give a molding composition or a molding. The product obtained has an increased amino end group content and consequently an improved hydrolysis 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 pressures, which considerably simplifies, in particular, the production of hollow bodies and hollow profiles having large diameters.
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:
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.