General Plastics (Leda)
Leda buttons were produced by General Plastics as a separate brand from around 1958. Advertising in 1958 referred to “Leda by Beauclaire”. However, In September 1957 the name ‘Leda’ was trademarked by Beutron, so the companies must have been merging, or General Plastics run as a subsidiary from that year. Some Leda cards had the free cotton wrapped around the card, which was a G. Herring/Beutron marketing tool, further confirming the ownership of Beutron of GP/Leda.

Spotted by Carol, but unfortunately not for sale.

A box that can hold around 6 cards of buttons.
Entries from the 1960 Sydney ‘Pink Pages’ directory: General Plastics made the buttons, but Roger Berry distributed them.
Leda had various labels on the cards, including Boil Proof, Fashion Buttons, Permaloid, Permalon and Permalite. Whether this actually refers to varying plastics or not is anyone’s guess without chemical testing! Often the same button appeared with different names:

Boilproof verses Fashion

Fashion verses Permaloid

Permalite verses Fashion
Boilproof

The blue card must be to reference Beutron’s “Boilproof Whites” which always appeared on blue cards.
Fashion

Pearlshell buttons

Gold metalised plastic or metal

Silver metalised plastic or metal
Permalon
Permaloid
Permalite
Buckle
Leda-Beauclaire cards, c.1958
Change of graphics: Possibly early 1960s

Cards with blue printing are uncommon.
1965-7

Approx 1968.
A little curiosity
Sample Cards
Leda Buttons Sold Under Other Brandings
Leda style buttons are found on Embassy (G.J. Coles brand) and Kencrest (David Kennedy brand) cards. See below for comparison:
Miscellaneous
Bias binding:

On a button covering machine.