<PAGE>

This instrument prepared by,
and after recording return to:

          Davis Polk & Wardwell
          450 Lexington Avenue
          New York, New York 10017
          Susan D. Kennedy, Esq.

================================================================================

             AMENDMENT NO. 1 TO MORTGAGE, ASSIGNMENT OF LEASES AND
                                    RENTS,
                  SECURITY AGREEMENT AND FINANCING STATEMENT


     THIS AMENDMENT NO. 1 TO MORTGAGE, ASSIGNMENT OF LEASES AND RENTS, SECURITY
AGREEMENT AND FINANCING STATEMENT (this "Amendment") is made as of the 1st day
of March, 2000 between REPUBLIC PAPERBOARD COMPANY, a Kansas corporation, having
an address at 811 East 30th Street, Hutchinson, Kansas 67503 (the "Mortgagor"),
and BANK OF AMERICA, N.A. (successor to NationsBank, N.A.), as Administrative
Agent., having an address at ___________________________ , not in its individual
capacity but in its limited capacity as Agent (as defined below) (the
"Mortgagee").

                             W I T N E S S E T H:

     WHEREAS, Republic Group Incorporated (the "Borrower"), certain Banks (the
"Banks"), the LC Issuing Banks referred to therein, Morgan Guaranty Trust
Company of New York, as Syndication Agent, and NationsBank, N.A., as
Administrative Agent for the Banks, are parties to a Credit Agreement dated as
of July 15, 1998 (as amended prior to the date hereof, the "Original Credit
Agreement");

     WHEREAS, pursuant to that certain Subsidiary Guarantee dated as of July 15,
1998 (as amended and in effect from time to time, the "Guaranty") from the
Subsidiary Guarantors (including Mortgagor) to the Agent, the Mortgagor
guaranteed the obligations of the Borrower under the Original Credit Agreement;

     WHEREAS, Mortgagor, in order to secure payment, performance and observance
of its indebtedness, liabilities and obligations arising under the Guaranty,
entered into a Mortgage, Assignment of Leases and Rents, Security
<PAGE>

Agreement and Financing Statement dated as of July 15, 1998 (the "Original
Mortgage") with the Mortgagee, which Mortgage was recorded on July 17, 1998 in
Comanche County, Oklahoma, as document number 014338, in Book 3056, Page 91,
which Mortgage encumbers the interest of Mortgagor in and to the parcel of land
and improvements thereon described in Exhibit A annexed thereto; and

     WHEREAS, the parties to the Original Credit Agreement are amending and
restating the Original Credit Agreement by entering into a First Amendment and
Restatement dated as of even date herewith (as so amended and restated, the "
Credit Agreement"); and

     WHEREAS, in connection with such amendment and restatement of the Original
Credit Agreement, the parties hereto have agreed to amend the Original Mortgage;

     NOW, THEREFORE, in consideration of the premises, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

     1.  All references in the Mortgage to "Credit Agreement" shall be deemed to
refer to the Amended and Restated Credit Agreement.

     2.  Recital D is hereby amended to read in full as follows:

         D.  The maximum principal indebtedness that may be
         secured by this Mortgage is $100,000,000. The scheduled
         maturity date of the latest to mature of the Secured
         Obligations (as defined below) is July 15, 2006.

     3.  Section 7.08 of the Mortgage is amended and restated to read in full as
follows:

          The Secured Obligations secured by this Mortgage
          include Revolving Credit Loans and LC Reimbursement
          Obligations which are revolving in nature, which may be
          advanced, paid, and readvanced from time to time after
          the date hereof. The aggregate maximum principal amount
          of Total Revolving Outstanding Amount which may be
          outstanding at any one time is $100,000,000. The
          aggregate maximum principal amount of Secured
          Obligations which may be outstanding at any one time is
          $100,000,000. The interest of the Mortgagee

                                       2

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          hereunder will remain in full force and effect
          notwithstanding a zero balance of the Total Revolving
          Outstanding Amount and the Lien of this Mortgage will
          not be extinguished until all Secured Obligations have
          been paid and performed and the obligation of all Bank
          Parties to extend further credit under the Loan
          Documents shall have expired or terminated.

     4.   Except as modified hereby, the terms and conditions of the Original
Mortgage remain unchanged and in full force and effect and are hereby ratified
and confirmed. Mortgagor hereby confirms that it has no defenses or offsets with
respect to its obligations under the Original Mortgage, as modified hereby.

     5.   This Amendment may be executed in counterparts, each of which shall
constitute an original and all of which together shall constitute the same
instrument.

                                       3

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     IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Amendment as of the date and year first above written.

                              REPUBLIC PAPERBOARD COMPANY,
                              as Mortgagor


                              By: /s/ Doyle R. Ramsey
                                 ---------------------------------------
                              Name:  Doyle R. Ramsey
                              Title: Executive Vice President & CFO



                              BANC OF AMERICA, N.A. (as successor to
                              NationsBank, N.A.), as Mortgagee



                              By: /s/ Thomas R. Mahoney
                                 ---------------------------------------
                              Name:  Thomas R. Mahoney
                              Title: Sr. Vice President
<PAGE>

State of Kansas      )

                         )
County of Reno       )

This instrument was acknowledged before me on February 29, 2000 by Doyle R.
Ramsey as EVP of Republic Paperboard Company, a Kansas corporation.

                                   /s/ Staci R. Hardesty
                                   ___________________________
                                   Notarial Officer



(Seal, if any)

__________________________
Title (and Rank)


My commission expires:

   5/7/2002
__________________________.
<PAGE>

State of Missouri    )

                        )
County of Jackson    )

This instrument was acknowledged before me on February 29, 2000
Thomas R. Mahoney as Sr. Vice President of Bank of America, N.A.

                                    /s/ Ayanna L. Woodson
                                   ___________________________
                                   Notarial Officer


(Seal, if any)

__________________________
Title (and Rank)


My commission expires:

   July 20, 2003
__________________________.





Drafted by and when
recorded, return to:


Susan D. Kennedy, Esq.
Davis Polk & Wardwell
450 Lexington Avenue
New York, New York 10017
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                                  EXHIBIT A
                            Description of the Land