I started using this kind of expanding agents in 1985 or 1986, it was AFAIK originally developed in Japan under the brand name Bristar:
http://www.taiheiyo-m.co.jp/english/product/productSubtop_4/
I believe it was invented and commercialized initially during the late 1960's/early 1970's:
http://www.fundinguniverse.com/company-histories/taiheiyo-ce...
I started using this kind of expanding agents in 1985 or 1986, it was AFAIK originally developed in Japan under the brand name Bristar:
http://www.taiheiyo-m.co.jp/english/product/productSubtop_4/
I believe it was invented and commercialized initially during the late 1960's/early 1970's:
http://www.fundinguniverse.com/company-histories/taiheiyo-ce...