(1)    Commingled goods. In this section, “commingled goods” means goods that are physically united with other goods in such a manner that their identity is lost in a product or mass.

   (2)   No security interest in commingled goods as such. A security interest does not exist in commingled goods as such. However, a security interest may attach to a product or mass that results when goods become commingled goods.

   (3)   Attachment of security interest to product or mass. If collateral becomes commingled goods, a security interest attaches to the product or mass.

   (4)   Perfection of security interest. If a security interest in collateral is perfected before the collateral becomes commingled goods, the security interest that attaches to the product or mass under sub. (3) is perfected.

   (5)   Priority of security interest. Except as otherwise provided in sub. (6), the other provisions of this subchapter determine the priority of a security interest that attaches to the product or mass under sub. (3).

   (6)   Conflicting security interests in product or mass. If more than one security interest attaches to the product or mass under sub. (3), the following rules determine priority:

      (a)    A security interest that is perfected under sub. (4) has priority over a security interest that is unperfected at the time the collateral becomes commingled goods.

      (b)    If more than one security interest is perfected under sub. (4), the security interests rank equally in proportion to the value of the collateral at the time it became commingled goods.