Pellets of a glass fiber-reinforced thermoplastic polymer composition, and method of their manufacture

Pellets of a glass fiber-reinforced thermoplastic polymer composition comprising a sheathed continuous multifilament strand comprising a core that extends in the longitudinal direction and a polymer sheath which intimately surrounds said core,

• wherein the core comprises at least one continuous glass multifilament strand,
• wherein the polymer sheath consists of a thermoplastic polymer composition comprising a polyolefin and having a melt flow index as measured according to ISO1133-1:2011 (2.16 kg/230° C.) of at least 1.0 dg/min and less than 20 dg/min,
• wherein the length of the glass filaments in the pellets is substantially the same as the pellet length, and is 10 to 55 mm,
• wherein the sheathed continuous multifilament strand comprises a polyethylene wax having MW of at most 10 kg/mol in an amount of less than 0.50 wt %, with respect to the sheathed continuous multifilament strand,
• wherein the polyolefin comprises or consists of a propylene homopolymer and a heterophasic propylene copolymer, wherein a weight ratio between the propylene homopolymer and the heterophasic propylene copolymer is 3:1 to 1:1,
• wherein the thermoplastic polymer composition comprises 0.1 to 5.0 wt % of an additive, with respect to the thermoplastic polymer composition,
• wherein a total amount of the continuous multifilament strand and the thermoplastic polymer composition is 100 wt %, with respect to the sheathed continuous multifilament strand, wherein the propylene homopolymer has a melt flow index as measured according to ISO1133-1:2011 (2.16 kg/230° C.) of 25 to 50 dg/min and the heterophasic propylene copolymer has a melt flow index as measured according to ISO1133-1:2011 (2.16 kg/230° C.) of 0.1 to 5.0 dg/min, and wherein the additive comprises a flame retardant.