FIRE-RETARDANT POLYAMIDE CAST ITEM INCLUDING AN INTUMESCENT COATING
Fire-retardant polyamide cast items including an intumescent coating are described. The case items can have excellent fire-retardant properties and can include at least one fire-retardant system in the polyamide matrix. The items can also have an intumescent coating on at least one surface.
1 . A flame-retardant article comprising, on a portion of at least one surface, an intumescent coating, wherein the article further comprises a polyamide composition comprising at least one flame retardant system.
2 . The article as defined by claim 1 , wherein the composition additionally comprises reinforcing fillers.
3 . The article as defined by claim 1 , wherein the flame retardancy system of the polyamide composition comprises at least one phosphorus-comprising flame-retardant agent selected from the group consisting of: a phosphine oxide, a phosphonic or a salt thereof, a phosphinic acid or a salt thereof, a cyclic phosphonate, an organic phosphate, an inorganic phosphate and a red phosphorus.
4 . The article as defined by claim 1 , wherein the flame retardancy system of the polyamide composition comprises at least one flame-retardant agent of a nitrogenous organic compound selected from the group consisting of: a triazine, a cyanuric acid, an isocyanuric acid, a melamine, a melamine oxalate, a phthalate, a borate, a sulfate, a phosphate, a polyphosphate, a pyrophosphate, a product condensed from melamine, a tris(hydroxyethyl) isocyanurate, a benzoguanamine, a guanidine, an allantoin and a glycoluril.
5 . The article as defined by claim 1 , wherein the flame retardancy system of the polyamide composition comprises at least one flame-retardant agent comprising brominated derivatives selected from the group consisting of: a PBDPO (polybromodiphenyl oxide), a BrPS (polybromostyrene or brominated polystyrene), a poly(pentabromobenzyl acrylate), a brominated indane, a tetradecabromodiphenoxybenzene, a 1,2-bis(pentabromophenyl)ethane, a tetrabromobisphenol A and a brominated epoxy oligomer.
6 . The article as defined by claim 1 , wherein the composition comprises from 5% to 40% by weight of a flame-retardant agent, with respect to the total weight of the composition.
7 . The article as defined by claim 1 , wherein the intumescent coating comprises an acid source, a carbon source, a blowing agent and a binder.
8 . The article as defined by claim 1 , wherein the intumescent coating is selected from the group consisting of: an aqueous coating, a glycero coating, a cellulose coating, a vinyl coating, an acrylic coating, a polyurethane coating and an epoxy coating.
9 . The article as defined by claim 1 , wherein the intumescent coating is a paint or a varnish.
10 . The article as defined by claim 1 , wherein said article is an extruded or injected article.
11 . A process for the manufacture of an article as defined by claim 1 , the process comprising applying an intumescent coating over at least one portion of a surface of the article, after having optionally treating the at least one portion of the surface of the article in order to increase adhesion between the at least one portion of the surface and the coating.
12 . The process as defined by claim 11 , in which the increase in adhesion between the at least one portion of the surface and the coating is brought about by plasma treatment or flame treatment.