Powder composition of polyarylene ether ketone ketones allowing an excellent castability/coalescence balance suitable for laser sintering

Abstract

A powder composition of polyarylene ether ketone ketones allowing an excellent castability/coalescence balance suitable for laser sintering. The present invention concerns a composition comprising between 99.6 and 99.99% by weight of at least one powder of at least one polyarylene ether ketone and 0.01 to 0.4% by weight of a hydrophilic flow agent. This hydrophilic flow agent is characterised by an increase in mass (quantity of water absorbed) of more than 0.5% after 5 days of conditioning at a relative humidity of 95%. This increase in mass of the flow agent is determined by means of a Karl Fischer measurement after desorption of the water by a 5-minute treatment at 170° C. This composition is suitable for laser sintering. In particular, it gives the powder an excellent castability/coalescence balance.

1 . A composition comprising from 99.6% to 99.99% by weight of at least one powder of at least one polyarylene ether ketone and 0.01% to 0.4% by weight of a hydrophilic flow agent, said hydrophilic flow agent being characterized by a gain in mass (amount of water absorbed), after 5 days of conditioning at a relative humidity of 95%, of greater than 0.5%, said gain in mass of the flow agent being determined by Karl Fischer measurement after desorption of the water by a 15-minute treatment at 170° C. 
     
     
         2 . The composition as claimed in  claim 1 , in which the hydrophilic flow agent is a hydrophilic silica. 
     
     
         3 . The composition as claimed in  claim 1 , in which at least one polyarylene ether ketone is PEKK. 
     
     
         4 . The composition as claimed in  claim 3 , in which the PEKK has a mass percentage of terephthalic units relative to the sum of the terephthalic and isophthalic units of between 55% and 85%. 
     
     
         5 . The composition as claimed in  claim 3 , in which, in addition to the PEKK, a PEK, PEEKEK, PEEK, PEKEKK or PEKK powder of different chemical structure is added, the PEKK representing more than 50% by mass, limit inclusive. 
     
     
         6 . The composition as claimed in  claim 1 , containing a filler. 
     
     
         7 . The composition as claimed in  claim 1 , containing at least one additive. 
     
     
         8 . The use of a composition as claimed in  claim 1  in a laser sintering process. 
     
     
         9 . An object obtained using a composition as claimed in  claim 1 .