STABILIZATION AND MODIFICATION OF POLYCAPROAMIDE - Photochemical Reactions in Heterochain Polymers - page 17

naphthoilene - bis - benzimidazole (II, III)under the name of Vat red 2G easily produces
“vat” of olive-green colour.
In most cases the ability to be reduced in agressive medium of PA melt is the negative
factor, since reduced form of the dye, as a rule, has another colour than initial keto-form, and
is characterized by decreased light fastness.
Unfortunately, today there are no clear pre-conditions for dyes selection and in each case
this problem may be solved only by empirical way. Nevertheless, the problem of obtaining
new thermostable dyes is still urgent.
Daylight - fluorescent pigments, which, in most cases, are solid solutions of luminescent
dyes in different polymers are used more often in different fields of science and engineering.
Here bright colours are obtained at small concentration of dyes. Some substituted of
aroilenbenzimidazole possess fluorescent properties and are used for preparation of daylight -
fluorescent dyes [114] and interest in this class of compounds [115] has grown when the
opportunity of their use for mass dyeing of polymers has been shown.
Over the last years Kavaliev and his research workers [116, 117] succeeded in
synthesizing luminophores in the series of naphthoilenbenzimidazoles, containing
fluorophoric groups. For mass dyeing of polymer materials there were proposed aryloxazoline
- and phylenoxadiazolil - naphthoilenbenzimidazoles [118, 119]:
where X=CHN
and also benzoxasolil -, benzimidazolye - and benziazolil - naphthoilenbenzimidazoles -
luminophores of yellow glow [120, 121].