Section 15. No retail installment sale agreement shall provide for or create a security interest in (a) personal property other than the goods sold or worked on under a retail installment sale agreement unless such goods become affixed to such personal property; (b) after-acquired collateral other than accessions to the goods sold or worked on; or (c) goods subject to a prior retail installment sale agreement or agreements unless two or more such agreements are consolidated under a single agreement pursuant to section eighteen.

Any agreement made in violation of this section may be declared void by the supreme judicial or superior court in equity upon petition of the installment buyer.