Polyester vs viscose rayon: choosing the best thread for the job

When discussing children and politics, broadcasting our favourite is generally not the done thing. But when it comes to embroidery, most experienced embroiderers are more than happy to let you know which camp they are in; polyester or viscose rayon.

But could personal preference be holding you back from using the right thread for the job? Choosing between them may not be easy as there are many similarities between the two. Both give amazing embroidered results; both also have hundreds of colours. And the similarities don’t stop there.

Both our polyester thread and viscose rayon have a thread count of 120d/2 (40s and are manufactured in our state-of-the-art factory, which has achieved ISO 9001 accreditation. In addition, the threads have achieved Oeko-Tex Standard 100 certification for environmental compliance in production, making them safe for use on all apparel, including child and infant clothing.

However, even with these similarities, it should be your end product that dictates which of these threads to choose. Factors such as durability, washing processes, end use and fabric are all contributing factors to the choice you make.

So, if you are now wondering whether you are using the right thread for the job, we’ve compiled a few thread facts that may just help inform your decision.

Polyester thread is more durable in extreme conditions
Rayon is a popular choice in fashion and keeps its colours bright and fresh with general domestic laundering. All our rayon threads are wash and boil fast (up to high temperatures), but due to the process in which they are made, they may not be as durable in really tough situations, especially if bleach is involved.

Take stonewashed embroidered denim for example – the process the fabric goes through to achieve the end look is punishing. Or even bathing suits, which are constantly subjected to chlorine in pool water. If you’re embroidering onto a garment like this or a product that will need to be heavily commercially laundered, then opt for our polyester thread. It is produced to withstand industrial detergents and bleach so won’t lose its colour.

It’s also a good idea not to mix the two threads for this reason (and also as they both stitch differently too). Over time one could fade whilst the other may keep its colour, meaning the design will distort and the longevity of the end product could be compromised.

Viscose rayon is soft to touch and stays soft even at high stitch counts
Less harsh than polyester thread, rayon is also much softer against skin making it the perfect choice for clothing as it’s less abrasive. Especially for items that are more ‘under’ wear than ‘outer’ wear – tie-offs behind an embroidered garment can actually be irritating when polyester thread is used. Softness can also apply to the machinery too. Viscose rayon can be gentler on the working parts of your embroidery machine and requires less tension.

Polyester thread is stronger
A big advantage of polyester thread is its ability to withstand extremes in temperature and humidity. Rayon thread on the other hand, if not kept well can break above the normal acceptable level. It’s worth looking at your storage solution if you find that you are having more thread breaks – it could be down to cold, dampness or humidity.

While it is true that polyester thread is stronger, it stretches further and then returns to its original shape. This can create a puckering problem so can require a watchful eye and need to adjust tensions (unless you have automatic thread tensioning). Occasional thread pull-ups or loops on top are also a common occurrence with any polyester thread.

Rayon is a natural fibre
Unlike most man-made fibres, it is made from wood pulp, a naturally occurring, cellulose-based raw material. Polyester on the other hand is made using a chemical reaction involving coal, petroleum, air and water.

They are both about equal when it comes to wear and tear of machines
However, as polyester is a synthetic material, it will stretch before it breaks, requiring a firmer tension than rayon on almost all machines. Properly set tensions will stop this as will proper adjustment when switching between the two threads. Some technicians also say that polyester wears a needle eye faster which causes breaks and snagging of threads. Again, properly maintained needles and changing when required can prevent any problems.

At the end of the day, both polyester and rayon have great benefits and in reality, your choice of thread may be preference. If you do require any information on any of our embroidery threads, what is best for the job or recommendations for a specific project, then please get in touch and one of our experienced team will help you decide which thread is right for you.