Elf Atochem S.a.

Atochem

Philippe Maj

Philippe Blondel

Jean-Marc Sage

Didier Judas

Daniel Cuzin

Noelle Forichon

The present invention relates to new polyamides comprising, on a mass basis: (a) 45 to 75% of an x,T unit, x being between 4 and 12 inclusive, the x,T unit being the condensation product of a diamine having x carbon atoms and of terephthalic acid, and (b) 55 to 25% of an aliphatic unit -HN-(CH.sub.2).sub.n -CO, n being between 6 and 14 inclusive. and the terpolyamides obtained by including a monomeric unit (c) such as the unit 6 or 6,I as a replacement for part of the aliphatic unit (b). The polyamide compositions thus obtained exhibit a Tg lower than 130.degree. C., a Tm higher than 230.degree. C. and a good crystallizability.

Polyamides and objects obtained from them

Transparent polyamide compositions having high resistance to chemical agents, as well as the process for their preparation and the articles obtained from said compositions. The present polyamide compositions contain from 1 to 99% by weight, preferably 40 to 90% by weight, of a first polyamide consisting of aliphatic units containing at least 7 carbon atoms, isophthalic and terephthalic diacids, the latter being predominant, and cycloaliphatic diamine units, and from 99 to 1% by weight, preferably 60 to 10%, of a semi-crystalline polyamide consisting of at least 35%, preferably 50%, by weight of an aliphatic unit containing at least 7 carbon atoms.

Transparent polyamide compositions having high resistance to chemical

A process for the manufacture of polyamides consisting essentially of the stages of:

Process for the preparation of polyamides with oligomer formation

Block copolyetheramides, well adopted for conversion into a wide variety of useful thermoplastic elastomer shaped articles, have the formula: ##STR1## in which D is the residue of a diacid oligamide having an Mn ranging from 300 to 3,000 and/or the residue of the diacid chain limiter, PE is the residue of a polyetherdiol having an Mn ranging from 200 to 5,000,.times.is a straight or branched chain (cyclo)aliphatic or aromatic hydrocarbon having from 4 to 20 carbon atoms, n is a number ranging from 1 to 4, and m is an average number ranging from 2 to 50; these are prepared by polycondensing a multiblock polymer having the formula: ##STR2## with a diamine H.sub.2 N--X--NH.sub.2.

Block copolyetheramides

Novel block polyetheramides, well adapted for the usual thermoplastic elastomer applications, e.g., as molded or extruded shaped articles, films, sheaths, composites and the like, have the following general formula: ##STR1## in which D is the residue of an oligoamidediacid having an Mn ranging from 300 to 8,000 and/or the residue of the diacidic polymer chain limiter, PE is the residue of a polyetherdiol having an Mn ranging from 200 to 5,000, X is a linear or branched, (cyclo)aliphatic or aromatic hydrocarbon having form 3 to 20 carbon atoms, R.sub.1 and R.sub.2, which may be identical or different, are either OH or H, n is a number ranging from 0.1 to 10, and m is an average number ranging from 2 to 50, and are prepared by reacting, in the molten state, an oligoamidediacid A with an oligotherdiol B and a low molecular weight diacidic coupler C, the respective molar percentages a, b and c of which being such that:

Block polyetheramides

A transparent polyamide containing terephthalic acid radicals or radicals of the mixture of terephthalic and isophthalic acids and a cycloaliphatic diamine radical and having the chain formations: ##STR1## in which: y.sub.1 +y.sub.2 is between 10 and 200 with y.sub.1 /(y.sub.1 +y.sub.2)&gt;0.5;

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Bad Honnes, Germany

Philippe Maj