Since it's stronger, why shouldn't I use polyester thread instead of rayon for all my decorative stitching?
There are certain thread companies (that sell only polyester thread) who feel the need to bash all rayon thread to get you to buy their Asian-made polyester. They claim that rayon is weak and it fades when you bleach it.
Regarding the colorfastness of Sulky Rayon Thread, it is (and always has been) 100% colorfast in hot or cold water and can be dry-cleaned. We have always recommended avoiding chlorine bleach, optical brighteners, peroxide, or sodium carbonate. By all means, use exceptionally high quality Sulky Polyester Thread (made in Germany) instead of Sulky Rayon when you intend to bleach the less than 1% of your items.
While it is true that polyester thread is stronger than Rayon, it is an unnecessary strength because Sulky Rayon is not a thread for sewing seams. Several million spools of Sulky Rayon Thread have been sold EVERY YEAR FOR THE LAST 25 years to discerning consumers in the United States and Canada who want the most beautiful, softest-looking, silkiest, shiniest Decorative Thread for their embellishments and machine embroidery. Knowledgeable consumers know that Sulky Rayon Thread has the perfect strength for these applications.
Another important fact about Sulky Rayon Thread is that it comes from cellulose, which is harvested from wood pulp. So, not only is it predominately a natural product, its main source is also renewable since the trees are grown on plantations specifically for producing Rayon/Viscose fibers. The process from greenhouse, to plantation, to harvest takes seven years. Compared to Polyester, a completely man-made fiber that comes from Oil, an all too familiar non-renewable resource, Rayon is friendlier to the environment!
Additionally, Polyester threads have more stretch and much more memory, which causes them to stretch further and return to their original shape. This can create a puckering problem if not dealt with properly by adjusting tensions and increasing stabilizing. Occasional thread pull-ups or loops on top are a common occurrence with any polyester.
Sulky Rayon, on the other hand, stretches less and then relaxes so the stitches lay beautifully, and since beauty is the whole reason for decorative thread, hundreds of thousands of people prefer Sulky Rayon for its warmer look and feel.
While there are numerous companies selling rayon thread, All Sulky Rayon Threads Are Made Exclusively From Enka Fibers, Proven To Be The Highest Quality Rayon/Viscose Fibers In The World.
The world renowned ENKA plant in Obernburg, Germany produces raw viscose fibers exclusively from long-chain, consistently high quality cellulose molecules, and all Sulky Rayon Threads are now (and always have been) made exclusively with ENKA raw fibers, which have been tested and certified to be the highest quality rayon/viscose fibers in the world. We invite you to read the Sulky/Enka Proof of Quality to get the whole story.
Because ENKA fibers have a more even form and structure, they can be dyed more evenly. ENKA fibers also have more perfect optical refraction and cleanness of yarn to make Sulky Rayon threads appear glossier and more brilliant. That's why embroidery connoisseurs prefer the softer, warmer, more natural look of Sulky Rayon Thread. It's no wonder Sulky 40 wt. rayon threads are the strongest, most brilliant rayon threads available.
Indeed, Sulky is the only thread company in the world who has been granted the right to display the Enka Logo along with the Sulky logo to signify that we exclusively use only their raw goods to produce our exceptionally high quality thread.