EXHIBIT 10.4 PATENT SECURITY AGREEMENT ------------------------- PATENT SECURITY AGREEMENT, dated as of April 2, 2004, by DARLING INTERNATIONAL INC., a Delaware corporation ("Grantor"), in favor of GENERAL ELECTRIC CAPITAL CORPORATION, a Delaware corporation, in its capacity as Administrative Agent for Lenders ("Administrative Agent"). W I T N E S S E T H: - - - - - - - - - - WHEREAS, pursuant to that certain Credit Agreement dated as of the date hereof by and among Grantor, the Persons named therein as Credit Parties, Administrative Agent and the Persons signatory thereto from time to time as Lenders (including all annexes, exhibits or schedules thereto, and as from time to time amended, restated, supplemented or otherwise modified, the "Credit Agreement"), Lenders have agreed to make the Loans and to incur Letter of Credit Obligations for the benefit of Grantor; WHEREAS, Administrative Agent and Lenders are willing to make the Loans and to incur Letter of Credit Obligations as provided for in the Credit Agreement, but only upon the condition, among others, that Grantor shall have executed and delivered to Administrative Agent, for itself and the ratable benefit of Lenders, that certain Security Agreement dated as of the date herewith (including all annexes, exhibits or schedules thereto, as from time to time amended, restated, supplemented or otherwise modified, the "Security Agreement"); WHEREAS, pursuant to the Security Agreement, Grantor is required to execute and deliver to Administrative Agent, for itself and the ratable benefit of Lenders, this Patent Security Agreement; NOW, THEREFORE, in consideration of the premises and mutual covenants herein contained and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Grantor hereby agrees as follows: 1. DEFINED TERMS. All capitalized terms used but not otherwise defined herein have the meanings given to them in Annex A thereto to the Credit Agreement. 2. GRANT OF SECURITY INTEREST IN PATENT COLLATERAL. Grantor hereby grants to Administrative Agent, on behalf of itself and Lenders, a continuing first priority security interest in all of Grantor's right, title and interest in, to and under the following, whether presently existing or hereafter created or acquired (collectively, the "Patent Collateral"): (a) all of its Patents and Patent Licenses to which it is a party including those referred to on Schedule I hereto; (b) all reissues, continuations or extensions of the foregoing; and (c) all products and proceeds of the foregoing, including, without limitation, any claim by Grantor against third parties for past, present or future infringement or dilution of any Patent or any Patent licensed under any Patent License. 3. SECURITY AGREEMENT. The security interests granted pursuant to this Patent Security Agreement are granted in conjunction with the security interests granted to Administrative Agent, on behalf of itself and Lenders, pursuant to the Security Agreement. Grantor hereby acknowledges and affirms that the rights and remedies of Administrative Agent with respect to the security interest in the Patent Collateral made and granted hereby are more fully set forth in the Security Agreement, the terms and provisions of which are incorporated by reference herein as if fully set forth herein. 4. COUNTERPARTS. This Patent Security Agreement may be executed in any number of separate counterparts, each of which shall collectively and separately constitute one agreement. Delivery of an executed signature page of this Patent Security Agreement by facsimile transmission shall be effective as delivery of a manually executed counterpart hereof. [signature page follows] 2 IN WITNESS WHEREOF, Grantor has caused this Patent Security Agreement to be executed and delivered by its duly authorized officer as of the date first set forth above. DARLING INTERNATIONAL INC., as Grantor By: /s/ John O. Muse ----------------------------------- Name: John O. Muse --------------------------------- Title: Executive Vice President -------------------------------- ACCEPTED AND ACKNOWLEDGED BY: GENERAL ELECTRIC CAPITAL CORPORATION, as Administrative Agent By: /s/ Texas Howard ----------------------------------- Name: --------------------------------- Title: -------------------------------- ACKNOWLEDGMENT OF GRANTOR ------------------------- STATE OF Texas ) ----------------------- ) ss. COUNTY OF Dallas ) ---------------------- On this 1st day of April, 2004 before me personally appeared John O. Muse, proved to me on the basis of satisfactory evidence to be the person who executed the foregoing instrument on behalf of DARLING INTERNATIONAL INC., who being by me duly sworn did depose and say that he is an authorized officer of said corporation, that the said instrument was signed on behalf of said corporation as authorized by its Board of Directors and that he acknowledged said instrument to be the free act and deed of said corporation. /s/ Peggy J. Jones --------------------------- Notary Public {seal} 3 SCHEDULE I ---------- to PATENT SECURITY AGREEMENT PATENT REGISTRATIONS -------------------- - ------------------------------------ --------------------------------- --------------------------------- --------------------------- PATENT PATENT NO. DATE ISSUED COUNTRY - ------------------------------------ --------------------------------- --------------------------------- --------------------------- Automated Waste Cooking Grease 5,812,060 September 22, 1998 U.S. Recycling Tank - ------------------------------------ --------------------------------- --------------------------------- --------------------------- 4