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PET-PTT Bicomponent Yarn

-- Steady & Reliable Manufacturer --

What Is PET-PTT Bicomponent Yarn

PET-PTT bicomponent yarn is a side-by-side filament made of two polyester variants: standard PET (polyethylene terephthalate) on one side and PTT (polytrimethylene terephthalate) on the other. The two polymers are extruded together in the same filament, and because PTT has a different molecular structure and shrinkage behavior than PET, the filament curls into a natural spiral crimp once it is heat-set.

This self-crimping effect is what gives PET-PTT yarn its signature stretch and recovery, similar in performance to some spandex-covered yarns, but achieved entirely within a single polyester-based filament, with no elastane involved. It is often referred to in the market by brand-style names, but structurally it is a side-by-side bicomponent yarn built specifically for stretch performance.

Why the Spiral Crimp Matters

Unlike mechanically textured yarn, the crimp in PET-PTT yarn comes from the permanent difference in shrinkage between the two polymer sides, so it is more durable through repeated stretching, washing, and heat exposure. This makes it attractive for stretch fabrics that need to hold their shape over the life of the garment.

Production at GC FIBER

We run PET-PTT on dedicated bicomponent spinning positions with tight control over the PET/PTT ratio and cross-section symmetry, which directly affects crimp level, bulk, and stretch recovery in the finished fabric.

Related products

Services

We insist on timely and fast service, the implementation of all-weather tracking service, adequate spare parts inventory, so that our customers have no worries.

  • Wide Variety

    Wide Variety

    Design & Manufacturing. In stock or customizable.

  • Sample and Catalog

    Sample & Catalog

    OEM/ODM available.

  • Production and Delivery

    Production & Delivery

    Flexible production and delivery policies

  • Business Experience

    Business

    Over 19 years of experience in eco-friendly textile products

Specification

CompositionPET (polyethylene terephthalate) + PTT (polytrimethylene terephthalate), side-by-side
PET/PTT Ratio50:50 standard; 60:40 / 40:60 available on request
Cross-SectionSide-by-side, round filament profile
Total Denier Range50D – 300D
Filament Count24F / 36F / 48F / 72F (custom counts available)
Stretch (Elongation Recovery)Elastic recovery typically 85%-95% at 20% extension
Crimp Contraction20% – 35% after heat setting
Tenacity2.8 – 4.0 cN/dtex
Elongation at Break25% – 45%
Boiling Water ShrinkageHigher than standard PET by design, used to drive the crimp effect
ColorRaw white / dope-dyed / customer-specified shade
PackageCone (1.5 – 2.5 kg net), carton packing
MOQ300 kg per specification for standard grades

Application

PET-PTT bicomponent yarn is used wherever a fabric needs built-in stretch and recovery without adding spandex to the yarn count. Common applications include:

  • Stretch woven fabric: shirting and bottom-weight fabric that needs comfort stretch without a spandex core-spun yarn.
  • Activewear and sportswear: leggings, yoga wear, and base layers where recovery and shape retention matter through repeated movement.
  • Socks and hosiery: improved fit and stretch recovery around the leg and ankle.
  • Denim-look stretch fabric: spandex-free stretch denim that avoids some of the durability issues associated with elastane over time.
  • Upholstery and stretch home textiles: fabrics that need to keep their shape under repeated tension.

Advantage

  • Spandex-free stretch: stretch and recovery come from the polymer structure itself, so the yarn avoids issues like spandex degradation from chlorine, heat, or UV exposure.
  • Durable crimp: the spiral crimp is set into the filament permanently, so it holds up over many wash and wear cycles better than mechanically textured stretch yarns.
  • Easier recycling and fabric composition: a 100% polyester-based stretch yarn can simplify recycling compared to polyester/spandex blends.
  • Soft, silky hand-feel: PTT contributes a softer touch and better resilience compared to standard PET alone.
  • Consistent crimp performance: our process control on ratio and cross-section symmetry keeps crimp level and stretch behavior stable batch to batch.

Payment Terms

We accept T/T (30% deposit, balance before shipment or against copy of B/L), L/C at sight for bulk orders, and Western Union / PayPal for sample orders. Quotations are given in USD by default.

Shipping & Delivery

Standard terms are FOB Shanghai / Ningbo, with CIF and DDP available on request. Samples ship by express courier within 3-5 working days. Bulk production lead time is typically 12-20 days after deposit and spec confirmation, shipped by sea freight (FCL/LCL), with air freight available for urgent schedules.

  • Q: How does this yarn stretch without any spandex in it?
  • A: The PET and PTT sides shrink at different rates during heat setting, which causes the filament to form a permanent spiral crimp that behaves like a built-in spring.
  • Q: Is the stretch as strong as spandex-blended fabric?
  • A: It offers good comfort stretch and recovery for most apparel needs, though very high-stretch applications like swimwear may still prefer a spandex-blended fabric alongside this yarn.
  • Q: Can the PET/PTT ratio be customized?
  • A: Yes, the standard ratio is 50:50, and other ratios such as 60:40 or 40:60 can be arranged to fine-tune the crimp level and stretch behavior.
  • Q: Does this yarn need special dyeing conditions?
  • A: It generally dyes similarly to standard polyester with disperse dyes, though we recommend confirming temperature and time with our technical team for your specific fabric construction.
  • Q: What is the minimum order quantity?
  • A: Standard MOQ is 300 kg per specification; smaller trial quantities can be discussed for new buyers testing the yarn on their lines.
About
GC FIBER
GC FIBER has been a special textile factory in China since 2006 years. We are devoted to researching, developing, producing, and selling special and functional eco-friendly textile products.
Our products include Biodegradable Yarn, Low Melting Yarn, ECDP Yarn, Anti Static Yarn, HDPE Yarn, Bio-component Yarn, and Polyester Filament Yarn.
We are always interested in cooperating with our guests to develop new material.

WHY WE ARE SO TRUSTED

We have got a high reputation in both domestic and overseas markets.

Professional

We will communicate with customers professionally, listen to their opinions and give useful suggestions, and spend time and energy to solve every problem, no matter all the problems you encounter.

Quality

We have strict quality control requirements and the advanced testing equipment in the industry. Every process has professionals to conduct inspections to ensure product quality.

Cost

We have a number of production lines, a number of production machines, comprehensively improve product quality and production efficiency.

Design and R&D

We devote to research, development, production and sales of special and functional eco-friendly textile product.

Diversity

Our product includes PBS biodegradable product, recycled easy dyeing cationic yarn, PLA yarn, Low melting yarn, Anti-Static yarn ,PBS fiber, PLA fiber, FR nylon fiber etc.

Capacity

The company has sufficient production capacity and high control over raw material prices, quality and stable supply, which can meet the needs of customers with different procurement volumes.

Service

We insist on timely and fast service, the implementation of all-weather tracking service, adequate spare parts inventory, so that our customers have no worries.

Shipment

We are near Ningbo Port and Shanghai Port, and are very convenient and quick to transport cargo to other national capitals.

Diversified Professional Team

GC FIBER has unique sales, research and development, design, production departments and expertise to provide customers and stakeholders in various industries with specialty, functional and environmentally friendly textiles.

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