The NRA Blue Eagle label was used in the USA only from 1933-35.
The US National Labor Relations Act was passed in 1935.
The National Recovery Board was brought into effect in 1934
The ILGWU (International Ladies’ Garment Workers’ Union) was formed in 1900. It joined the CIO (Congress of Industrial Organizations) in briefly in 1937.

YKK – Japan, a zipper company founded in Japan in 1934.
Talon Zippers – USA – since 1894.
Lightning Zippers- Canada.
Eclaire Zippers- France.
KIN Zippers – Germany.
Coil zippers – invented in 1940, but not in common usage until the early 1960s.
Side seam zippers – late 1930s-1960s.
Short CB neck zippers – mostly 1930s-1940s.
Sleeve zippers – 1930s and 1940s.
Center back dress zippers – seen occasionally in the 1940s and early 1950s, but generally later 1950s and 1960s and always from the 1970s on.
Velcro® was invented in 1948, not used in clothing much until 1960s.