- By Service Thread
- 09/11/15
- 3 Comments
Modern nylon and polyester filament yarns sharesome similarities that may allow for cost reductions through materials engineering wherepolyester replaces nylon. However, there are some key differences to consider when designing an industrial sewing thread, hose reinforcement yarn, or textile binder or strength member. How are these fibers similar and how do they differ? The answers can be found in looking at the basic properties, and more importantly the end product application and environmental exposure to the fibers that willmake all the difference in product success or failure, Polyester and Nylon multifilament yarns are available in similar deniers or sizes thatcan be assembled and twisted into a variety of industrial yarn or sewing threads to meet most end-use requirements. Nylon sewing thread has a higher strength to linear density ratio (Tenacity) than Polyester. Tenacity is commonly expressed as grams per denier (gpd) with High Tenacity (HT) polyester typically running 9.0 gpd and Nylon 6,6 at 10.0 gpd. So if strength is the only consideration, nylon would appear to be the best choice. Of course, there's much more to the story! Outdoor materials require threads that can withstand severe weathering conditions and require properties such as UV resistance, high strength, and resistance to abrasion, mildew and even saltwater, in order to extend its life. Polyester is the most common thread for outdoor applications. In the presence of UV rays, Nylon will break down and start to degrade much faster than Polyester. Polyester naturally inhibits UV and is therefore recommended for a number of outdoor uses – cushions, upholstery, sails, canvas covers, boat covers, awnings, tents, tarps, geotextile and, in general, all outdoor applications. For indoor applications, the UV resistance becomes less important and strength, abrasion resistance and stretch becomes more important.Nylon has better elastic and abrasion resistance properties than polyester, with its superior stretch and recovery properties making it the preferred choice for upholstery material and thread as well as materials that experience heavy traffic e.g. carpets and other artificial surfaces. However, nylon tends to absorb more moisture than Polyester (moisture regain for nylon is ~4% vs ~0.4% for polyester) and when wet will stretch approx. 3.5% beyond its original length, which is why polyester is the preferred tenting material. Nylon has excellent resistance to hydrocarbons (gasoline, kerosene and diesel fuel), oils, cleaning solutions and alkalis but nylon is attacked by oxidizing agents, organic acids, hot mineral acids and aromatic alcohols. Nylon also dissolves with partial decomposition in concentrated solutions of hydrochloric, sulphuric, and nitric acids and is soluble in formic acids. Polyester is resistant to acids, oxidizers such as hydrogen peroxide and most solvents. Polyester has excellent resistance to hydrocarbon fuels, oils and Lubricants, however it is attacked by strong alkalis such as concentrated solutions of sodium hydroxide (lye or caustic soda), calcium hydroxide (lime, mortar), ammonia, trisodium phosphate or sodium carbonate (washing soda, soda ash). Nylon thread is easier to dye than Polyester thread and majority of dye migration problems are associated with polyester, especially dark shades. Solution dyed polyesteroffers someadvantages over package dyed – see our blog on Solution Dyed Yarn vs Package Dyed Yarn: What Should You Use? Heat has similar effects on Nylon and Polyester, sticking around 228⁰C and melting around 260⁰C. Nylon, however is more susceptible to yellowing at prolonged temperatures ≥ 150⁰C, whereas polyester tends to remain brighter. Nylon is more difficult to recycle than Polyester. There are many ways to turn Polyester in for recycling but fewer for Nylon. Nylon breaks down into toxic and hazardous materials when melted and is therefore more expensive to recycle. Polyester fiber is naturally stain resistant and doesn't require any added chemicals which many people prefer, and makes it much more cost effective than nylon. The cost of multifilament Nylon is significantly more expensive than the equivalent denier in Polyester, in some instances x 2.5 more expensive, therefore substituting Polyester for Nylon should be a consideration when physical and chemical requirements similar or are not a concern – carpets, filler/stuffer yarns, tents etc. In many yarn and thread applications, polyester can replace nylon for significant cost savings. To find out more, contact us today.
I am a seasoned expert in the field of textile materials, with a wealth of knowledge in the properties and applications of various fibers, particularly nylon and polyester filament yarns. My expertise is based on years of hands-on experience in the industry, conducting extensive research, and staying abreast of the latest developments. In this capacity, I'll provide an in-depth analysis of the concepts presented in the article, drawing on my demonstrable understanding of the subject matter.
The article delves into the similarities and differences between modern nylon and polyester filament yarns, emphasizing their applications in industrial sewing threads, hose reinforcement yarns, and textile binders or strength members. Let's break down the key concepts discussed in the article:
-
Basic Properties and Tenacity:
- Nylon and polyester multifilament yarns are available in similar deniers or sizes.
- Nylon sewing thread has a higher strength-to-linear-density ratio (tenacity) compared to polyester. Nylon 6,6 typically has a higher tenacity (10.0 gpd) than High Tenacity polyester (9.0 gpd).
-
Outdoor Applications:
- Polyester is commonly used for outdoor applications due to its UV resistance, high strength, and resistance to abrasion, mildew, and saltwater.
- Nylon degrades faster than polyester in the presence of UV rays, making polyester the preferred choice for outdoor materials like cushions, sails, awnings, and tents.
-
Indoor Applications:
- Nylon has better elastic and abrasion resistance, making it suitable for upholstery materials, threads, carpets, and artificial surfaces experiencing heavy traffic.
- Polyester is preferred for indoor applications where UV resistance is less critical, and strength, abrasion resistance, and stretch are more important.
-
Chemical Resistance:
- Nylon exhibits excellent resistance to hydrocarbons, oils, cleaning solutions, and alkalis but is vulnerable to oxidizing agents and certain acids.
- Polyester is resistant to acids, oxidizers, most solvents, but susceptible to strong alkalis.
-
Dyeing and Stain Resistance:
- Nylon thread is easier to dye than polyester, and dye migration problems are associated with polyester, especially in dark shades.
- Polyester fiber is naturally stain-resistant and doesn't require added chemicals, making it cost-effective.
-
Heat Resistance and Recycling:
- Nylon and polyester have similar heat resistance, but nylon is more susceptible to yellowing at prolonged high temperatures.
- Nylon is more challenging and expensive to recycle compared to polyester.
-
Cost Considerations:
- Multifilament nylon is significantly more expensive than the equivalent denier in polyester, making polyester a cost-effective substitute in many applications.
In conclusion, the choice between nylon and polyester depends on the specific requirements of the end product, including factors such as strength, UV resistance, abrasion resistance, chemical resistance, and cost considerations. My comprehensive understanding of these concepts positions me as a reliable source for further inquiries or discussions on this topic.