Many polypropylene spinning factories set dosing ratio of Polypropylene masterbatch simply based on color‑card experience, ignoring chain changes of melt fluidity and fiber mechanical indicators caused by proportion adjustment. It may result in qualified color but increased filament breakage and declined fiber strength.

Polypropylene masterbatch features high pigment concentration. Higher dosing ratio does not always bring better coloring effect. Excessive dosage mixes massive pigment particles into polypropylene melt and changes rheological property. Melt viscosity fluctuates, filter‑pressure at spinneret rises rapidly and shortens assembly service cycle, leading to more frequent shutdowns. Excess pigment also interferes polymer‑chain combination and reduces breaking strength and elongation of finished filaments or staple fibers, failing mechanical acceptance requirements for webbing and geotextile products.

Insufficient dosing ratio leads to poor color saturation. Repeated feed‑rate adjustment for target shade will cause batch‑to‑batch color deviation. Suitable dosing ranges differ among color series. Dark‑color masterbatch with high pigment content works well at low addition level; light‑color products demand higher cleanliness, and proportion shall be calculated according to hiding power instead of unified parameters.

Besides theoretical proportion, feeding‑system stability shall not be neglected. Poor calibration of loss‑in‑weight feeders causes unstable actual masterbatch feeding and color deviation even with correct setting. Yancheng Ruize Color Masterbatch Co., Ltd. provides recommended dosing ratio of Polypropylene masterbatch according to spinning equipment, target shade and fiber denier, and optimizes formula through sample trials.

Before full‑scale color change production, spinning manufacturers shall carry out small‑batch trial, verify both color performance and fiber mechanical property, and start mass production only when fiber performance remains intact, balancing coloring effect and production‑line stability.