Introduction to identification skills of PP fiber

1. Comparative visual inspection method
High-quality fiber, neat length, uniform thickness, light and bright white color. Doubled yarn, sizing yarn, thick yarn, rolled yarn, oily yarn, agglomerated yarn and little or no impurities are considered high quality; the opposite is true for inferior quality.

2. Water bath comparison method
Take 500ml of water and put it into two cups, add 0.4g of fiber with the same specifications respectively, stir for 10 seconds and observe. The high-quality ones are evenly dispersed and suspended in the water; the inferior ones cannot be dispersed evenly or are suspended in the water or water in the form of balls or clusters. Down.

3. Odor identification method
High-quality fiber: environmentally friendly, bland and non-irritating; inferior fiber: polluting, strong-flavored and highly irritating.

4. Water removal method
Some inferior polypropylene fibers contain moisture (which is difficult to feel with human hands). The moisture content can be measured by drying or sun-drying. Although the fiber is cheap, it contains water. Assuming the moisture content is 5%, then 1 kilogram of fiber containing moisture is actually only 95% fiber, and the fiber price will be 1.05 times the original price.

5. Sunlight exposure method
Inferior polypropylene fiber, due to cost reduction, has not been treated with UV resistance at all, and polypropylene fiber loses its strength in one or two years under sunlight, so it is difficult for inferior polypropylene fiber to play its role in concrete for a long time. The difference can be made by simply conducting random inspections at the construction site (strictly identifying whether the filaments submitted for inspection are consistent with the polypropylene fiber short filaments at the construction site), and then testing their tensile strength after being exposed to the sun and night for a long time.

6. Detection method
The fibers of polypropylene fiber produced from recycled materials: ① have low tensile strength, generally <350Mpa; ② have high elongation, generally > 60%; ③ have poor alkali resistance, because both mixed concrete and hardened concrete are highly alkaline. (pH ≥ 12), in this environment the strength of the fiber will gradually decrease, so that it will play a very small role in concrete and cannot improve the mechanical properties of concrete at all. It can be carried out through random inspection at the construction site (the filament submitted for inspection must be strictly identified to be consistent with the polypropylene fiber short yarn at the construction site), and then submitted for inspection.