Disclosed herein are a polyamide composition and a molded article made of the same with improved mechanical strength and reduced weight. The molded article may include the polyamide composition that includes high flowable polyamide and polyphthalamide and a small-diameter fiber, thereby resulting in an improvement in mechanical strength while achieving excellent surface properties and high weight reduction.

A method for producing a polycondensate powder dispersion, characterised in that it includes at least one step of polycondensation: i) of at least one diester and at least one diamine, and/or ii) at least one amino ester, while stirring, in a solvent that can solubilise both the diamine and the diester and/or the amino ester but not the polyamide that forms during the polycondensation, at a temperature between 30° C. and the boiling temperature of the solvent, in order to produce a powder precipitate dispersed in the solvent.

Provided are that a cage for a rolling bearing in which seizure or break is not generated under a condition of a high temperature and a high speed in which a dm.Math.n value is not less than 80×10.sup.4, and a rolling bearing using the cage. The rolling bearing 1 is provided with an inner ring 2, an outer ring 3, a plurality of rolling elements 4 interposed between the inner ring and the outer ring and a cage 5 which retains the rolling elements 4. The cage 5 is formed by injection molding a resin composition. The resin composition comprises polyamide resin made from a dicarboxylic acid component and a diamine component as a base resin and a fiber reinforcing member added. The dicarboxylic acid component contains terephthalic acid as a main component. The diamine component contains 1,10-diaminodecane as a main component. The fiber reinforcing member contains 15 to 50 mass % of glass fibers or 10 to 35 mass % of carbon fibers based on the whole resin composition.

In a first process, a resin molded article having a predetermined shape is molded. Next, in a second process, a surface of the resin molded article is treated with plasma in a vacuum to provide irregularities in the surface of the resin molded articles. In the second process, discharge ignition is performed in inert gas to generate plasma, and while a degree of vacuum is maintained, raw material gas is then replaced by air.

The invention concerns a thermoplastic composition having high fluidity in the molten state, comprising at least: (a) one thermoplastic polymer matrix; (b) one oligomer selected from cyclic ester oligomers, ether oligomers and mixtures thereof, said oligomer having a degree of polymerization of between 2 and 25; and (c) one phenolic polymer; said compounds (b) and (c) being present in a weight ratio (c)/(b) varying from 0.25 to 6, and preferably from approximately 0.75 to 2.75.

The invention also concerns a process for producing a composite article from such a composition by impregnating a reinforcement such as a fabric or a preform, the composite article obtained according to this process, and the use of an oligomer (b) in combination with at least one phenolic polymer (c), as a plasticizing additive in a thermoplastic polymer matrix.

The invention relates to a thermoplastic composition having improved fluidity in the molten state, comprising at least: (a) a polyamide that has a melt viscosity greater than or equal to 50 Pa.Math.s, and (b) a non-evolutive polyamide having a melt viscosity lower than the melt viscosity of said polyamide (a), above 0.8 Pa.Math.s, and having a number-average molecular weight Mn lower than that of said polyamide (a), said composition having a melt viscosity that is stabilized at a value below the melt viscosity of said polyamide (a), said polyamide (b) having: a concentration of amine end groups (AEG) and/or of carboxyl end groups (CEG) less than or equal to 20 meq/kg, or a concentration of amine end groups (AEG) greater than or equal to 25 meq/kg; a concentration of acid end groups (CEG) greater than or equal to 25 meq/kg; and a concentration of blocked end groups (BEG) greater than or equal to 25 meq/kg.

Provided is a pressure vessel having an outer layer with an improved gas barrier property, a lightweight liner with an excellent gas barrier property, and a novel method for manufacturing a pressure vessel. The pressure vessel contains a liner and an outer layer of the liner, wherein the outer layer is configured by a composite material that contains a continuous fiber and a polyamide resin impregnated into the continuous fiber; the polyamide resin contains a structural unit derived from diamine and a structural unit derived from dicarboxylic acid; and 50 mol % or more of the structural unit derived from diamine is derived from xylylenediamine.

The present invention relates to a thermoplastic resin composition, which achieves barrier properties against various types of gases, while maintaining flexibility, and a molded body comprising the same. The thermoplastic resin composition of the present invention is characterized in that it comprises an aliphatic polyamide, a semi-aromatic polyamide, and an impact modifier, wherein at least a part of the impact modifier is dispersed in the semi-aromatic polyamide, in the semi-aromatic polyamide, the molar ratio between diamine units and dicarboxylic acid units (the number of moles of diamine units/the number of moles of dicarboxylic acid units) is in the range of 0.97 to 1.02, and the mass ratio of the impact modifier to the total mass of the semi-aromatic polyamide and the impact modifier is in the range of 5% to 15%.

The present invention provides a composite molded body in which a rubber layer in the form of a thin film is formed on a surface of a resin molded body and a production method therefor. According to an embodiment of the present invention, a liquid composition containing a rubber component such as a rubber latex and a peroxide is applied to a surface of a resin molded body such as a polyamide-based resin having an amino group, causing crosslinking to occur in an uncrosslinked rubber layer and forming a crosslinked rubber layer in the form of a thin film. When a co-crosslinking agent is used in combination, adhesion to the resin molded body can be improved even when the thickness of the crosslinked rubber layer is small.

The invention relates to a stretched polymer film made of a polyamide composition comprising a semi-crystalline semi-aromatic polyamide (PPA), wherein the PPA consists of repeat units derived from aromatic dicarboxylic acid comprising at least 80 mole % of terephthalic acid, relative to the total amount of aromatic dicarboxylic acid; and diamine comprising at least 5 mole % 1,4-butanediamine and at least 5 mole % 1,6-hexanediamine, relative to the total amount of diamine, the combined amount of 1,4-butanediamine and 1,6-hexanediamine being at least 60 mole % relative to the total amount of diamine; and 0-2 mole % of other monomeric units, relative to the total amount of aromatic dicarboxylic acid, diamine and other monomeric units. The invention further relates to a process for preparing the polyamide film by melt extrusion and stretching of the film.