The invention relates to a process for preparing a semi-aromatic polyamide from diamine and dicarboxylic acid, comprising steps of •(i) dosing a liquid diamine to an agitated powder comprising an aromatic dicarboxylic acid thereby forming a powder comprising a diamine/dicarboxylic acid salt (DD-salt), and •(ii) solid-state polymerizing the DD-salt to obtain the polyamide.

A polyamide molding material is proposed, which comprises at least one partially crystalline, partially aromatic polyamide (A) and at least one amorphous polyamide (B). The polyamides (A) and (B) together make up 30-60 wt.-% of the polyamide molding material. Furthermore, the polyamide molding material comprises 40-70 wt.-% glass fibers (C) having flat cross section, 0-15 wt.-% of at least one nonhalogenated flame retardant (D), and 0-10 wt.-% further additives (E), the components (A) to (E) adding up to 100 wt.-% of the polyamide molding material. The at least one partially crystalline, partially aromatic polyamide (A) has a glass transition temperature of at least 105° C. The polyamide molding material according to the invention is preferably distinguished in an injection-molding burr formation test in that, at a melt temperature of 320° C. and a tool temperature of 90° C., and a dynamic pressure of 100 bar and a holding pressure of 400 bar, at the flow path end of a mold arm having a vent gap dimension of 30 μm, burrs having a length G of at most 30 μm result. Such a polyamide molding material results in molded parts having good surface quality and low warpage when injection molded and is suitable for the production of housings or housing parts of electrical and electronic devices.

The polyamide production method of the present invention comprises the steps of: producing a low-order condensate by effecting a polycondensation reaction between a dicarboxylic acid component containing between about 5 and about 40 mol. % of terephthalic acid, and a diamine component containing between about 70 and about 100 mol. % of a xylylenediamine in which the content of paraxylylenediamine is between about 50 and about 100 mol. %, under conditions of a reaction temperature of at least about 200° C. and less than about 230° C.; discharging and cooling the low-order condensate at a pressure at or below atmospheric pressure, in an inert gas atmosphere; and subjecting the discharged and cooled low-order condensate to solid state polymerization. The production method makes it possible to obtain a polyamide having outstanding mechanical strength, heat resistance, color tone and the like without problems such as gelling.

A polymer dispersion is disclosed. The polymer dispersion includes a liquid crystal polymer powder, a polyamide acid, and a solvent. A solid content of the polymer dispersion includes the liquid crystal polymer powder and the polyamide acid. The liquid crystal polymer powder has a mass ratio of 20% to 30% in the solid content. The polyamide acid has a mass ratio of 70% to 80% in the solid content. The polyamide acid is obtained by mixing two kinds of diamines and two kinds of dianhydrides together, causing the diamines and the dianhydrides to be polymerized with each other. Both two kinds of diamines and two kinds of dianhydrides comprise a liquid crystal structure and a flexible structure respectively. A method of preparing the polymer dispersion, and a method for preparing a polymer composite film using the polymer dispersion are also disclosed.

Described herein are electrical articles comprising a polyamide (PA). As explained in detail below, the polyamide (PA) is a semi-aromatic polyamide derived from the polycondensation of an aliphatic diamine, terephthalic acid, and a bis(aminoalkyl)cyclohexane or a cyclohexanedicarboxylic acid. It was surprisingly discovered that incorporation of the cycloaliphatic diamine bis(aminoalkyl)cyclohexane or the cycloaliphatic dicarboxylic acid cyclohexanedicarboxylic acid into the polyamide provided for polymer compositions (PC) having significantly improved comparative tracking index (“CTI”) retention after heat aging, relative to analogous polyamides derived from only the aliphatic diamine and terephthalic acid. Due at least in part to the improved CTI retention, the polyamides (PA) can be desirably incorporated into articles that, during use, are exposed to elevated temperatures and benefit from high CTI performance.

An apparel textile yarn includes a polyamide. The polyamide includes a nylon and a polyetheramine. The polyetheramine has a molecular weight of at least 1500 and an Amine Hydrogen Equivalent Weight (AHEW) of less than 10 percent higher than the idealized AHEW for the polyetheramine. The polyamide may have a moisture regain ranging from about 10% to about 30%.

The present invention is a water-dispersible resin composition containing: a resin α that includes, in the main chain thereof, a structure M having two aromatic rings linked by a sulfide group, a sulfonyl group, an imide group, or a keto group; and a resin β having a hydrophilic group, the resins α and β being configured to form a co-continuous structure including three-dimensional continuous phases of the resins α and β. The present invention can provide a water-dispersible resin composition that maintains the heat resistance of the polymer material and can be removed only with water.

This polyamide resin composition contains: 30-89.9 parts by mass of a polyamide resin (A) having a melting point of at least 300° C.; 0-45 parts by mass of a polyamide resin (B) having substantially no melting point; 0.1-5 parts by mass of a light-transmitting pigment (C); and 10-55 parts by mass of a fibrous filler (D) (the total amount of (A), (B), (C), and (D) is 100 parts by mass). The polyamide resin (A) contains at least a terephthalic acid-derived component unit. In a molded body of the polyamide resin composition, the corrected heat of fusion (ΔHR) is 10-70 J/g, and the transmittance of laser light having a wavelength of 940 nm is at least 15% at a thickness of 1.6 mm.

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.

The invention provides a polyamide resin composition (1) containing a polyamide (A) and a free volume modifier (B), and having a free volume, as measured according to a positron annihilation method, of 0.0545 nm.sup.3 or less. The invention also provides a polyamide resin composition (2) prepared by adding from 0.005 to 1.200 parts by mass of a polysilsesquioxane (B) whose main chain is comprised of siloxane bonds, to 100 parts by mass of a polyamide (A) that contains a diamine unit including an aromatic diamine unit represented by the following general formula (I) in an amount of 70 mol % or more and a dicarboxylic acid unit including at least one of a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and an aromatic dicarboxylic acid unit represented by the following general formula (II-2) in a total amount of 50 mol % or more: ##STR00001##
wherein n in the general formula (II-1) indicates an integer of from 2 to 18, and Ar in the general formula (II-2) represents an arylene group.