Patent ID: 7736563

Claim:
A process for preparing a full dull polyamide-6 yarn, comprising: preparing titanium dioxide slurry by wetting, grinding, concentration correcting, sedimentation and storing, mixing water with caprolactam to form a caprolactam-water mixture, then a step of polymerizing the caprolactam in the caprolactam-water mixture to form polyamide-6, adding the titanium dioxide slurry to the caprolactam-water mixture during the step of polymerizing the caprolactam, spinning the polyamide-6 and titanium dioxide to form the full dull polyamide-6 yarn, adding 0.1 to 0.5% by weight of a phosphate salt relative to the weight of titanium dioxide as a wetting agent, and adding a naphthalene sulfonate based salt along with the titanium dioxide slurry to the caprolactam-water mixture during the step of polymerizing the caprolactam.