Flame-retardant plastic composition, yarn and textile structure coated therewith

Abstract

A halogen-free flame retardant plastic composition, for coating a substrate, comprising an acrylic resin and an intumescent agent. It is in the form of plastisol, and comprises therefore a plasticizing medium wherein the acrylic resin and the intumescent agent are dispersed, said plastisol being formulated such that, in combination: the viscosity remains not more than 6000 mPa's, measured with a Brookfiled RVT viscometer at 20 revolutions per minute, its rheological behaviour is pseudo-plastic and Newtonian.

1 . Method for obtaining a yarn comprising a core and a plastic sheath comprising an halogen-free flame-retarded composition, containing at least one acrylic resin and an intumescent agent which are dispersed in a plasticizing medium, the method comprising:
 a) providing a die suitable for passing the core of said yarn therethrough;   b) ungelling the plastic composition to be in a plastisol state;   c) passing the core of the yarn through said die, with a peripheral distribution of said plastisol around said core;   d) gelling the fire-retarded composition, wherein the rheological properties of the plastisol at the shear rate of the die, at least equal to 20,000 s −1 , are adapted by formulating said ungelled plastisol so that at low shear rate, at most equal to 400 s −1 , it exhibits a Newtonian behaviour, with a viscosity of less than or equal to 6 000 mPa.s, measured with a Brookfield RVT viscometer at 20 rpm, and at high shear rate, at least equal to 10,000 mPa.s, it exhibits a pseudoplastic behaviour.   
   
   
       2 . The method according to  claim 1 , wherein the plasticizing medium contains an organic phosphate as the major component by weight in said plasticizing medium and a phthalate. 
   
   
       3 . The method according to  claim 2 , wherein a weight proportion of the plasticizing medium comprising the phosphate is at most equal to 200% with respect to the weight of acrylic resin and/or a weight proportion of the intumescent agent is at most equal to 200% with respect to the weight of acrylic resin. 
   
   
       4 . The method according to  claim 1 , wherein the proportion by weight of the plasticizing medium in the plastisol is between 100 and 200% by weight of resin. 
   
   
       5 . The method according to  claim 1 , wherein the proportion by weight of the plasticizing medium in the plastisol is between 120 and 145% by weight of resin. 
   
   
       6 . The method according to  claim 1 , wherein the proportion by weight of the intumescent agent in the plastisol is between 50 and 200% by weight of resin. 
   
   
       7 . The method according to  claim 1 , wherein the proportion by weight of the intumescent agent in the plastisol is between 150 and 200% by weight of resin. 
   
   
       8 . The method according to  claim 1 , wherein the core material is a continuous glass filament. 
   
   
       9 . A composite flame retardant yarn with a sheath of resin of low combustibility obtained by the method according to  claim 1 . 
   
   
       10 . The yarn according to  claim 9 , wherein the core material is a continuous glass filament. 
   
   
       11 . A textile structure in which yarns as claimed in  claim 9  are assembled or entangled. 
   
   
       12 . A sun screen comprising a textile structure as claimed in  claim 11 . 
   
   
       13 . A sign comprising a textile structure as claimed in  claim 11 . 
   
   
       14 . A covering for walls or ceilings, comprising a textile structure as claimed in  claim 11 .