Intro
Continuous filament threads can be exposed to severe torsional and mechanical stress during sewing. Repeated directional changes, zigzag movements, coarse thread sizes and high friction may cause the thread structure to open or untwist. This can reduce sewing stability and create an uneven seam appearance.
Bonding stabilises the individual filaments and helps the thread retain its structure during processing. The main benefit is improved resistance to untwisting and more reliable sewing in demanding operations. Bonding does not automatically make every seam stronger; the final seam performance still depends on the raw material, thread size, stitch type and seam construction.
When is bonding particularly useful?
Bonded threads are especially relevant for multidirectional sewing, zigzag seams, heavy-duty topstitching and applications where the thread repeatedly changes direction around guides, needle eyes or material edges. They are commonly used in footwear, leather goods, outdoor products, upholstery, automotive interiors and technical textiles.
Key factors to consider
- Sewing direction: The more frequently the stitch path changes, the more important resistance to untwisting can become.
- Thread size: Coarse continuous filament threads are more visibly affected if the structure opens during sewing.
- Raw material: Polyester and polyamide provide different balances of weather resistance, abrasion resistance and elongation.
- Appearance: Bonded products are available with different looks, from smooth technical surfaces to a more textile character.
- Application environment: Outdoor exposure, automotive requirements or protective applications may require additional UV, heat or chemical resistance.
Typical applications
- Shoes and leather goods
- Bags and luggage
- Awnings and outdoor furniture
- Boat covers and sails
- Upholstery
- Automotive interiors and steering wheels
- Technical textiles and composites
Find the right AMANN solution
| AMANN product | Recommended use within this solution |
|---|---|
| Serabond | Bonded polyester continuous filament for outdoor applications, with excellent UV resistance and suitability for multidirectional sewing. |
| Outdoor-Pro | Bonded polyester thread combining UV resistance, a PFAS-free water-repellent finish and a textile appearance. |
| Strongbond | Bonded polyamide 6.6 continuous filament for highly durable seams in footwear, bags, luggage and leather goods. |
| Strongcore | Bonded polyamide 6.6 thread with brilliant colours and a textile look and feel. |
| Strongbond+ | Bonded polyamide thread for demanding automotive applications. |
| Kc-tech | Bonded para-aramid continuous filament for technical textiles requiring cut and heat protection. |
Important technical note
The suitability of a sewing thread depends on the complete combination of material, seam construction, stitch type, needle, machine settings and finishing processes. Individual sewing trials and application-specific testing are recommended before production.