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Side-by-Side Bicomponent Yarn

-- Steady & Reliable Manufacturer --

What Is Side-by-Side Bicomponent Yarn

Side-by-side bicomponent yarn is a broad construction category where two polymers, or two versions of the same polymer with different viscosity or shrinkage, are extruded together lengthwise along the filament, sitting next to each other rather than one inside the other. Because the two halves shrink at different rates when heated, the filament naturally curls into a spiral or zig-zag crimp, giving the yarn built-in bulk and stretch.

This construction covers several common polymer pairings, including PET/PTT for stretch yarn, PET/PET with different intrinsic viscosity for self-crimping bulk yarn, and PP/PE for lower-cost crimped fiber used in nonwovens. What they share is the same underlying mechanism: a differential shrinkage that produces a mechanical spring effect built directly into the fiber.

Why Mills Use Side-by-Side Yarn

Fabric producers use this construction to add stretch, bulk, or loft to a fabric without introducing spandex or going through a separate texturing process, since the crimp develops during standard heat setting.

GC FIBER's Side-by-Side Range

As a manufacturer, we offer several polymer combinations under this construction, and can help you choose the right pairing and ratio based on the stretch level, bulk, and hand-feel your fabric needs.

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

Common Polymer PairingsPET/PTT, PET/PET (different viscosity), PET/PA, PP/PE
Cross-SectionSide-by-side, both polymers extending the full filament length
Component Ratio50:50 standard; adjustable per pairing and target crimp level
Total Denier Range50D – 600D depending on polymer pairing and end use
Filament Count24F – 144F (custom counts available)
Crimp Contraction15% – 35% after heat setting, depending on pairing
Tenacity2.8 – 4.5 cN/dtex, depending on polymer combination
Elongation at Break20% – 50%
Elastic RecoveryUp to 90%+ at moderate extension for stretch-oriented pairings
ColorRaw white / dope-dyed / customer-specified shade
PackageCone, bale, or as agreed depending on filament vs staple form
MOQ300-500 kg per specification, depending on polymer pairing

Application

Because side-by-side construction covers several polymer combinations, its applications span both apparel and technical textiles:

  • Stretch apparel fabric: woven and knit fabrics needing comfort stretch without spandex, using PET/PTT or similar pairings.
  • Bulked continuous filament (BCF) carpet yarn: self-crimping PET/PET yarn used to add loft and coverage in carpet and rug backing.
  • Nonwoven thermal bonding: PP/PE side-by-side fiber used where extra bulk is needed alongside bonding capability.
  • Socks, activewear, and hosiery: fabrics that benefit from natural crimp-driven stretch and softness.
  • Home textiles and upholstery: bulkier, more voluminous fabric surface without extra texturing steps.

Advantage

  • Built-in crimp, no extra texturing step: the spiral crimp forms during standard heat setting, saving a separate texturizing process.
  • Flexible polymer pairing: we can match PET/PTT, PET/PET, PET/PA, or PP/PE to your target stretch level, bulk, and cost point.
  • Durable, permanent crimp: since the crimp is a physical property of the filament rather than a temporary mechanical texture, it holds up over the life of the fabric.
  • Good cost-to-performance ratio: adds stretch or bulk more economically than adding spandex or specialty elastic yarns in many constructions.
  • Manufacturer-direct customization: as the spinner, we can adjust component ratio and cross-section to hit a specific crimp and recovery target for your fabric.

Payment Terms

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

Shipping & Delivery

Standard terms are FOB Shanghai / Ningbo, with CIF and DDP arranged on request. Samples typically ship by express courier within 3-5 working days. Bulk production lead time is generally 12-25 days depending on the polymer pairing and order volume, shipped by sea freight (FCL/LCL) or air freight for urgent orders.

  • Q: What makes side-by-side yarn different from sheath-core yarn?
  • A: In side-by-side yarn, the two polymers sit next to each other along the full filament length, causing crimp, while in sheath-core yarn one polymer fully surrounds the other, which is used mainly for bonding or protective functions rather than crimp.
  • Q: Which polymer pairing should we choose for our fabric?
  • A: It depends on your goal: PET/PTT suits stretch apparel fabric, PET/PET with different viscosity suits bulked carpet-type yarn, and PP/PE suits nonwoven fiber needing both bulk and bonding ability. Our team can help you decide based on your fabric spec.
  • Q: Does the crimp level stay the same after repeated washing?
  • A: Yes, because the crimp is set into the fiber structure itself during heat setting, it remains stable through normal washing and wear rather than relaxing out over time.
  • Q: Can you match a target denier and filament count for our knitting machine?
  • A: Yes, denier and filament count can be adjusted within the ranges we offer, and we recommend sharing your machine gauge and target fabric weight so we can suggest the best match.
  • Q: What is the sample process before placing a bulk order?
  • A: We can send sample cones or a small batch for trial knitting or weaving, usually within 3-5 working days, so you can confirm crimp level and hand-feel before committing to a full order.
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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