Mich. Comp. Laws § 454.151

Sec. 1. That any number of persons not less than 5, may associate themselves together and become a body corporate and politic for the improvement of their several social and material interests, the regulation of their wages, the laws and conditions of their employment, the protection of their joint and individual rights in the prosecution of their trades or industrial avocations, the collection and payment of funds for the benefit of sick, disabled, or unemployed members, the securing of benefits to the families of deceased members, and for such other and further objects of material benefit and protection as are germain to the purposes of this act. The persons so associating shall execute articles of association as hereinafter provided, sign and acknowledge the same before some officer duly authorized by the laws of this state to take acknowledgments of deeds, and upon the execution and acknowledgment of said articles of association aforesaid, the said association shall become a body politic for the purposes set forth in said articles of agreement.