This subchapter shall not apply to any provision or agreement relative to arbitration contained in a collective bargaining contract entered into prior to August 28, 1957, or after October 6, 1967, or to any agreement to submit to arbitration an existing controversy entered into prior to August 28, 1957, or after October 6, 1967. [1969, c. 287, §2(AMD).]
26 M.R.S. § 960