What is the difference between polypropylene FDY silk and polyester FDY silk?

polypropylene FDY silk and polyester FDY yarn have the following differences:

Raw materials and production

polypropylene FDY silk: The by-product of petroleum refining propylene as raw material, by polymerization, melt spinning and other processes made.

Polyester FDY filament: Polyethylene terephthalate (PET) is produced from refined terephthalic acid (PTA) or dimethyl terephthalate (DMT) and ethylene glycol (EG) through esterification or transesterification and condensation polymerization, and then made by spinning and post-processing.

Physical property

Density: The density of polypropylene FDY silk is 0.91g/cm3, about 34% lighter than polyester, and under the same weight, polypropylene can cover a larger area.

Strength: The strength of both are higher, but the polyester staple fiber strength is 2.6-5.7cn/dtex, high-strength fiber is 5.6-8.0cn/dtex, although the strength of polypropylene is also higher, but generally slightly lower than polyester. However, the strength of polypropylene filament is second only to that of nylon, and the price is relatively low.

Elasticity: Polyester elastic close to wool, elongation of 5%-6% can be almost completely recovered, the elastic modulus of 22-141cn/dtex, polypropylene initial modulus is high, excellent elasticity, but the overall elastic performance is not as good as polyester.

Wear resistance: polypropylene has excellent wear resistance, can withstand frequent friction and is not easy to damage, better than polyester.

Hygroscopicity: the hygroscopicity of polypropylene is very small, almost no hygroscopicity, and the moisture regain rate is close to zero under general atmospheric conditions; Polyester also has poor hygroscopic properties, with a common moisture regain of 0.4%, but it is relatively good in synthetic fibers.

Chemical property

Acid and alkali resistance: polypropylene and polyester have good acid and alkali resistance, polypropylene has significant stability to inorganic acid and alkali; Polyester is resistant to dilute alkali and is not afraid of mold, but hot alkali can decompose it.

Light resistance: polypropylene has poor light resistance, poor thermal stability and easy aging; Polyester has better light resistance, second only to acrylic fiber.

Appearance and feel

Polypropylene FDY filament: The appearance and feel of polypropylene in the form of fine denier filament have been greatly improved, but overall it may still be relatively rough.

Polyester FDY silk: Modern technology makes polyester fiber more delicate, soft, gloss and drape better.

Dyeing property

Polypropylene FDY silk: usually dyed with the stock solution, the pigment is fused and evenly distributed in the fiber, the color fastness is good, there is no fading and contamination problems.

Polyester FDY silk: dyeing is more difficult, poor dyeability, because there is no specific dyeing group on the molecular chain and the polarity is small, but the color fastness after dyeing is good, not easy to fade.

Application field

polypropylene FDY silk: often used in sportswear, seamless underwear, sports socks, etc., can also be used in webbing, safety net belt, industrial suspenders, flexible container bags, geotextile, industrial filter cloth, rope, optical cable, high pressure fire hose, conveyor belt and so on.

Polyester FDY silk: widely used in clothing fabrics, bedding, decorative supplies, such as the production of shirts, dresses, curtains, sofa covers, etc., but also used in some of the higher strength and wear resistance requirements of industrial textiles, such as tire cord, geoggrid and so on.