https://www.rongduthread.com/products/heavy-duty-polyester-embroidery-thread/ Polyester Embroidery Threads Wholesale Heavy duty embroidery thread consists of strong polyester continuous filament. Though rayon thread used to be the most popular embroidery thread, thick polyester thread has made large strides since it has been invented. Polyester is more strong, durable and colorfast than rayon. Therefore polyester bulk embroidery thread works great for making up embroidery design on thick fabric, especially outdoor fabric, without abrading, breakage and color fading, such as thick gold embroidery thread. What's more, it's still quite affordable and cost-effective as it has the unique advantages.