Koret dress fabric ID help

[Slimewarp]

Hi friends! I'm relatively new still when it comes to vintage fashion/fabric identification, and am hoping for some help with this 50s Koret of California secretary's (?) Excuse if i use the wrong terms when describing, and please correct me so I can learn!!
Dress from an estate sale. It has a medium-heavy hand, not very stiff, not itchy (kinda like cotton more so than wool) with some stretch. All over pattern (is this considered brocade?) Inside is basically flat compared to outside. I want to be able to accurately describe my pieces when I list them, so u greatly appreciate the help. Thank you!

 

[Pinkcoke]

I can see that is a double knit and it looks remarkably similar to Crimplene, though this was a British yarn and fabric so perhaps a close competitor?
http://vintagefashionguild.org/fabric-resource/crimplene/
Crimplene was polyester. Your description of the fibre does sound man made. If you can find a thread end to take a small snip from, (usually in a knit garment the panels will have been joined together at some seams with a piece of yarn that ends in a long 'tail) a burn test could identify the fibre the yarn is made from.
http://vintagefashionguild.org/determining-fiber/
Both the design, fabric and zip would lead me to think your dress is more likely 1960s.

 

[Slimewarp]

Thank you! I was just about to do a burn test, though I am admittedly not great at the smell part, my nose gets confused lol. I'll take a look at the Crimplene info, thanks again!

 

[cmpollack]

I have the same dress (in my closet; I love it!) in gold with turquoise piping. It's not polyester--it's 100% cotton with the "permathal everglaze" finish Koret had been applying to its cotton knits since the mid 50s, to make them shrinkage-, stain-, and wrinkle-resistant. They called the 1961 collection this dress was from their "Swirl Knits", and sometimes referred to it as a jacquard. Koret experimented with all kinds of miracle fabrics in the 50s and early 60s, combining rayon, arnel/nylon and acetate with cotton, glazing cotton knits, and making orlon sweaters, but they didn't use poly that early!

(The ad is for educational purposes only... )

 

[Slimewarp]

Oh wow thank you for that info! So intetesting, and I love the ad!