What in heaven's name is Crylor, you ask? Just plain old acrylic! Crylor is the French term for it that is generally no longer in use, but was used in the mid-20th century.
Acrylic is very, very important in the textile world because it can be blended with just about everything and acts as a stablizer and helps prevent pilling.
Picture from molliesvintage.com (an amazing vintage dress source!!)