35 ILCS 640/2-6
The application of every exemption, credit and deduction against tax imposed by this Law, shall be limited by a reasonable and appropriate sunset date. A purchaser subject to the tax imposed by this Law is not entitled to take the exemption, credit, or deduction beginning on the sunset date and thereafter. If a reasonable and appropriate sunset date is not specified in the Public Act that creates the exemption, credit, or deduction, a purchaser shall not be entitled to take the exemption, credit, or deduction beginning 5 years after the effective date of the Public Act creating the exemption, credit, or deduction and thereafter. The provisions of this Section shall not apply to the exemption provided by Section 2-5 of this Law.
35 ILCS 640/2-6