Abstract: There are described copolyamides which are soluble in organic polyamide solvents and contain recurring structural units of the formulae Ia, Ib, Ic and Id or Ia, Ib, Id and Ig or Ia, Ib, Ic, Id and Ig and optionally of the formulae Ie and/or If--OC--Ar.sup.1 --CO-- (Ia),--NH--Ar.sup.2 --NH-- (Ib),--NH--Ar.sup.3 --NH-- (Ic), ##STR1##--OC--R.sup.2 --CO-- (Ie),--NH--R.sup.3 --NH-- (If),--OC--Ar.sup.4 --CO-- (Ig),whereAr.sup.1 and Ar.sup.2 are each independently of the other divalent aromatic radicals whose valence bonds are in the para or a comparable coaxial or parallel position relative to one another,Ar.sup.3 and Ar.sup.4 are each independently of the other divalent radicals whose valence bonds are in the meta or a comparable kinked position relative to one another,R.sup.1 is lower alkyl, lower alkoxy or halogen, andR.sup.2 and R.sup.3 are each independently of the other divalent aliphatic, cycloaliphatic or araliphatic radicals.

Abstract: Aromatic copolyamides are described, which are soluble in organic amide solvents. The polymers are composed to at least 95 mol % of repeat structural unitsA: --OC--AR--CO--B: --HN--Ar'--NH--C: --HN--Ar"--NH-- ##STR1## in the combinations A+B+C+D, or A+C+D+E and up to 5 mol % of m-bond-containing structural units F and/or G derived from aromatic dicarboxylic acids (F') and/or from aromatic diamines (G'), the sum total of the mole fractions of structural units A+F and the sum total of the mole fractions of the structural units of B+C+D+E+G being essentially the same, --Ar-- and --Ar'-- are divalent aromatic radicals whose C--N valence bonds are in a para-position or in a similar coaxial or parallel position and which may be substituted by one or two inert radicals, such as lower alkykl or halogen, ##STR2## is a trivalent aromatic radical which after removal of the --SO.sub.2 R group has the same meaning as --Ar-- or --Ar'-- or else is the structural unit ##STR3## wehre X is --O--, --NHCO--, --SO.sub.

Abstract: Aromatic copolyamides, preparation thereof and structures formed therefromThere are described aromatic copolyamides which are soluble in organic solvents for polyamides and which comprise at least 95 mol % of recurring structural units of formulae ##STR1## and up to 5 mol % of meta-bonded structural units E and/or F derived from aromatic dicarboxylic acids (E') and/or from aromatic diamines (F'), the sum total of the mole fractions of structural units A+E and the sum total of the mole fractions of structural units B+C+D+F being essentially of equal magnitude.The copolyamides of the present invention can be processed into fibers having high strengths and high breaking extensions.

Abstract: Aromatic copolyamides, soluble in organic polyamide solvents, comprise at least 95 mol % of the recurrent structural units of the formulae ##STR1## and up to 5 mol % of structural units containing m-bonds. Here, --Ar--and --Ar'-- are divalent, unsubstituted or substituted aromatic radicals, the valency bonds of which are in the para-position or in a comparable coaxial or parallel position, and --R is a lower alkyl radical.

Abstract: Aromatic copolyamides, soluble in organic polyamide solvents, comprise at least 95 mol % of the recurrent structural units of the formulae ##STR1## and up to 5 mol % of structural units containing m-bonds. Here --Ar--is a divalent, unsubstituted or substituted aromatic radical, the valency bonds of which are in the para-position or in a comparable coaxial or parallel position, and --R--and --R' are different from one another and are lower alkyl radicals or lower alkoxy radicals.

Abstract: Aromatic copolyamides, soluble in organic polyamide solvents, comprise at least 95 mol % of the recurrent structural units of the formulae ##STR1## and up to 5 mol % of structural units containing m-bonds. --Ar-- and --Ar'-- are here divalent, unsubstituted or substituted aromatic radicals, the valency bonds of which are in the para-position or in a comparable coaxial or parallel position, and --R and --R' are different from one another and are lower alkyl radicals or lower alkoxy radicals.

Abstract: The invention relates to filaments, fibers, pulps, films and sheets from a copolyamide which has at least the recurring structural units of the formulaeA --OC--AR--CO--B --NH--Ar'--NH-- ##STR1## and in which the diamine components B, C and D relative to the total amount of diamine components in mol-% are within a predetermined domain. Such copolyamides can be produced from the corresponding diamines and dicarbonyl dichlorides in aprotic solvents in the presence or absence of metal halides of the first or second group of the periodic table. The spinning solutions obtainable therein can be processed in conventional manner into the claimed shaped structures.

Abstract: Organic carbodiimides are prepared by heating isocyanates of formulaR -- (NCO).sub.nwhereinR is an organic radical andn is 1 or 2In the presence of 2-methyl-2,5-dioxo-1-oxa-2-phospholane having the structure ##STR1## as catalyst as temperatures of about 50.degree. to 250.degree. C. The special catalyst not only gives good to excellent yields but, also allows the process to be carried out safely on an industrial scale.

Abstract: Fibers, filaments and sheets from aromatic polyamides which are dyeable with cationic dyestuffs are prepared by solution polycondensation ofA. aromatic dicarboxylic acid dichlorides optionally containing up to 5 mol % of aliphatic and/or cycloaliphatic dicarboxylic acid dichloridesB. aromatic diamines optionally containing up to 5 mol % of aliphatic and/or cycloaliphatic diamines, andC. 2 to 15 mol %, relative to the total amount of dicarboxylic acid dichlorides, of 4-chlorocarbonyl-sulfobenzoic acid anhydride of the formula ##STR1## and subsequent neutralization and spinning.