Textile-grade High Viscosity Polyester Chip for Filament Spinning

Full-dull Semi-dull or Bright High IV Polymer for High Strength Yarn Production

High viscosity polyester chip is one specialty polymer with high intrinsic viscosity. IV is an important performance index of polyester chips. And it is the basis for measuring the average molecular weight of the chips. In the spinning process, the production parameters are set according to the intrinsic viscosity value. So the end-users pay much attention to the viscosity.

About Intrinsic Viscosity
The IV is around 0.645dl/g for regular PET chips in the textile field. While the high IV polyester chip can reach 0.90dl/g.
As for IV testing methods, different countries have different ways.

  • In China, we use phenol and tetrachloroethane. And the ratio of these two chemicals is 1:1. The testing temperature is 25℃.
  • For Turkey customers, the viscosity of the produced materials is measured with a Lauda D30KP 6 model viscometer device. The samples were dissolved in phenol / 1,2-dichlorobenzene (%60/%40) solution to measure the flow time at 25℃. Three measurements are performed for each sample to calculate average values.
  • For Indian customers, they Phenol / 1,1,2,2, Tetrachloroethane (60:40) solution and test it in Ubbelhode Viscometer at 25℃.

Different testing methods have different results, so it is very important to confirm the test methods before discussing the IV value.

It can be used for the production of industrial yarn, monofilament, and biofilament.
Here we want to explain more about the application in composite elastic fibers, which are characterized by a side-by-side structure. In order to produce this fiber, we can blend low-viscosity PET (0.47-0.65 dl/g) with high-viscosity PET (0.82-1.05 dl/g). And then adjust the temperature of the spinning components. The resulting composite fibers have good elasticity, strength, and chemical stability. It can improve the elasticity and hand feel of fabrics.
composite elastic fibers made from this method have a more competitive price than Spandex.


No. Property Unit Standard Value Test Method
1 Intrinsic Viscosity dl/g 0.900 ± 0.025
2 Diethylene Glycol (DEG) W/% ≤1.20 GB/T 14190-2017(5.2.1)
3 Carboxyl End Groups (COOH) mol/t ≤30
4 Melting Point 261±2 GB/T 14190-2017(5.3.1)
5 Color Value (b) 2 ± 2 GB/T 14190-2017(5.5.1)
6 Moisture Content % ≤0.4 GB/T 14190-2017(5.7.1)