815 ILCS 425/2

Whenever any association or union of workers has adopted or shall hereafter adopt for its protection any label, trade-mark, or form of advertisement, announcing that goods to which such label, trade-mark or form of advertisement shall be attached were manufactured by a member or members of such association or union, it shall be unlawful for any person or corporation to knowingly counterfeit or imitate such label, trade-mark or form of advertisement. Every person violating this Section shall be guilty of a Class A misdemeanor.