<PAGE>   1
                                                                   EXHIBIT 10.18

                                                        RESTRICTED STOCK
                                                   PURCHASE AGREEMENT dated as
                                                   of May 31, 2000 (this
                                                   "Agreement"), between
                                                   Huntsman Packaging
                                                   Corporation, a Utah
                                                   corporation (the "Company"),
                                                   and SCOTT K. SORENSEN (the
                                                   "Purchaser").

                  WHEREAS, the Purchaser is an employee of the Company;

                  WHEREAS, the Company desires to issue to the Purchaser, and
the Purchaser desires to purchase from the Company, shares of common stock of
the Company (the "Common Stock") in accordance with the terms and conditions set
forth below;

                  NOW, THEREFORE, in consideration of the agreements, covenants
and promises contained in this Agreement, intending to be legally bound, the
Company and the Purchaser agree as set forth below.

          SECTION 1.   ISSUANCE AND SALE.

             (a) The Company hereby issues to the Purchaser, and the Purchaser
hereby purchases and accepts from the Company, 6,750 shares of Common Stock (the
"Shares") at a purchase price of $483.00 per Share, for an aggregate purchase
price of $3,261,129 (the "Purchase Price"). The Purchase Price is payable by
delivery of a promissory note in the form attached as Exhibit A hereto (the
"Promissory Note"). The Company acknowledges receipt from the Purchaser of the
executed Promissory Note. To secure the Company's rights under the Repurchase
Option described in Section 2 and to secure the Purchaser's obligations under
the Promissory Note, the Company will retain possession of the certificate or
certificates representing the Shares.

          SECTION 2.   REPURCHASE OPTION.

             (a) Type of Shares.  1,125 of the Shares shall be "Time Vested
Shares" and 5,625 of the Shares shall be "Performance Vested Shares."

             (b) Repurchase Option on Termination of Employment. If the
Purchaser ceases to be an employee of the Company for any reason, with or
without cause, including death, Disability or Retirement, (a "Termination"), the
Company or its designees shall have an irrevocable, exclusive option (the
"Repurchase Option") for a period of 180 days from the date of Termination to
repurchase, at the original price per Share set forth in Section 1, all or any
portion of the Shares held by the Purchaser or any of his transferees on the
date of the Termination that have not been released from the Repurchase Option
as provided in Section 3; provided that if the Company shall be legally
prevented (whether by contract or statutorily) from making such repurchase
during the foregoing 180-day period, then such Repurchase Option may be
exercised within forty-five (45) days after the date on which it shall be
legally permitted to make such repurchase, but in no event shall the Company be
permitted to make such election after the third anniversary of the date of
Termination. In the event that the Company exercises the Repurchase Option at
any time after the 180th day after the date of Termination, the repurchase price
per

<PAGE>   2


Share shall be equal to the sum of (x) the original price per Share set forth in
Section 1 plus (y) interest on the unpaid amount of the original price per Share
set forth in Section 1 compounded annually, at a rate equal to seven percent
(7.0%) for the period commencing on the 181st day after the date of Termination
through the date on which the Shares are actually repurchased. As used herein
"Disability" and "Retirement" shall have the meanings given to such terms in the
Employment Agreement dated as of the date hereof (the "Employment Agreement"),
between the Company and the Purchaser.

             (c) Exercise of Repurchase Option. The Repurchase Option shall be
exercised by the Company, or its designee, by delivering to the Purchaser a
written notice of exercise and either (i) a check in the amount of the purchase
price, (ii) if there is an outstanding balance on the Promissory Note, a notice
stating that the repurchase price shall be applied to reduce the outstanding
principal and interest (or a portion thereof) on a dollar-for-dollar basis or
(iii) a combination of (i) and (ii). Upon delivery of such notice and payment of
the purchase price in any of the ways described above, the Company, or its
designee, shall become the legal and beneficial owner of the Shares being
repurchased and all rights and interest therein or related thereto, and the
Company, or its designee, shall have the right to transfer to its own name the
number of Shares being repurchased without further action by the Purchaser or
any of his transferees. If the Company or its designee elect to exercise the
repurchase rights pursuant to this Section 2 and the Purchaser or his transferee
fails to deliver the Shares in accordance with the terms hereof, the Company, or
its designee, may, at its option, in addition to all other remedies it may have,
deposit the purchase price in an escrow account administered by an independent
third party (to be held for the benefit of and payment over to the Purchaser or
his transferee in accordance herewith), whereupon the Company shall by written
notice to the Purchaser cancel on its books the certificates(s) representing
such Shares registered in the name of the Purchaser and all of the Purchaser's
or his transferee's right, title, and interest in and to such Shares shall
terminate in all respects.

          SECTION 3. RELEASE FROM REPURCHASE OPTION.

             (a) If the Purchaser is employed by the Company at the time of the
Purchaser's death, Disability or Retirement, all of the Performance Vested
Shares shall be automatically released from the Repurchase Option on the
effective date of such Termination.

             (b) If the Purchaser is employed by the Company continuously from
the date hereof through January 1, 2001, and the Purchaser has not experienced a
Termination on or prior to such date, all of the Time Vested Shares shall be
automatically released from the Repurchase Option on such date.

             (c) The Performance Vested Shares shall be automatically released
from the Repurchase Option in installments as follows:

                    (i) if the "Market Value Per Share of Equity" or MVPSE (as
         defined in Section 3(d)) is at least $603.75 (such amount, and each
         such amount specified in subsections (ii) through (vi) below, the
         "Target MVPSE") on December 31, 2000 (such date, and each such date
         specified in subsections (ii) through (vi) below, a "Target Date"),

                                       2
<PAGE>   3


         one-sixth of the Performance Vested Shares shall be released as soon
         as practicable after December 31, 2000;

                    (ii) if the MVPSE is at least $754.70 on December 31, 2001,
         one-sixth of the Performance Vested Shares shall be released as soon as
         practicable after December 31, 2001;

                    (iii) if the MVPSE is at least $943.40 on December 31, 2002,
         one-sixth of the Performance Vested  Shares shall be released as soon
         as practicable after December 31,  2002;

                    (iv) if the MVPSE is at least $1,179.25 on December 31,
         2003, one-sixth of the Performance Vested Shares shall be released
         as soon as practicable after December 31, 2003;

                    (v) if the MVPSE is at least $1,474.10 on December 31, 2004,
         one-sixth of the Performance Vested Shares shall be released as soon as
         practicable after December 31, 2004; and

                    (vi) if the MVPSE is at least $1,842.65 on December 31,
         2005, one-sixth of the Performance Vested Shares shall be released as
         soon as practicable after December 31, 2005.

             (d) Market Value Per Share of Equity.

                  The "Market Value Per Share of Equity" ("MVPSE") on any given
date shall equal (I) other than in connection with an Acceleration Event, the
quotient obtained by dividing (x) the difference between (A) the product of (1)
Adjusted EBITDA and (2) 8.0 and (B) Adjusted Net Debt by (y) the number of
outstanding Common Stock Equivalents or (II) in connection with an Acceleration
Event, the price (whether payable in cash or property) per Common Stock
Equivalent paid to stockholders or other securityholders of the Company in
connection with such Acceleration Event, where, in each case of (I) and (II):

                  "Common Stock Equivalent" means, at any time, one share of
Common Stock or the right to acquire, whether or not such right is immediately
exercisable, one share of Common Stock, whether evidenced by an option, warrant
or convertible security;

                  "EBITDA" equals earnings from operations before interest
expense, taxes, depreciation and amortization on the applicable date, determined
in accordance with generally accepted accounting principles, consistently
applied ("GAAP"), calculated on a trailing twelve (12) month basis;

                  "Adjusted EBITDA" equals the Company's EBITDA, as adjusted
below, on the applicable date;

                  "Net Debt" equals the Company's total indebtedness on the
applicable date plus the Preferred Value minus balance sheet "Cash and Cash
Equivalents" as of such date, determined in accordance with GAAP;

                                       3
<PAGE>   4

                  "Preferred Value" equals, at the time of determination, the
sum of (x) with respect to the Company's Series A Preferred Stock, the Series A
Liquidation Amount and (y) with respect to any other series of the Company's
preferred stock, the amount to be paid by the Company to the holders of such
series of preferred stock upon a liquidation of the Company or similar event in
accordance with the terms of the Restated Charter.

                  "Restated Charter" means the amended and restated certificate
or articles of incorporation of the Company, as in effect at the time of
determination, including any certificates of designation or articles of
amendment.

                  "Series A Liquidation Amount" has the meaning set forth in the
Restated Charter.

                  "Adjusted Net Debt" equals Net Debt, as adjusted below, on the
applicable date. Adjusted EBITDA and Adjusted Net Debt shall be determined by
making the following adjustments to the Company's EBITDA and to Net Debt:

                      (i) if the Company completes a material acquisition (an
         "Acquisition") during any of the first three quarters of a calendar
         year, the EBITDA of the acquired entity or business for the portion of
         the calendar year prior to the Acquisition shall be included in
         Adjusted EBITDA;

                      (ii) if the Company completes a material divestiture (a
         "Divestiture") during any of the first three quarters of a calendar
         year, the EBITDA of the divested assets or business for the portion of
         the calendar year prior to the Divestiture shall be excluded from
         Adjusted EBITDA;

                      (iii) if the Company engages in an Acquisition during the
         fourth quarter of a calendar year, an amount equal to the total of (x)
         all debt incurred with respect to the Acquisition and (y) all
         transaction costs associated with the Acquisition shall be excluded
         from Adjusted Net Debt; and

                      (iv) if the Company engages in a Divestiture during the
         fourth quarter of a calendar year, (x) the total amount of the proceeds
         received by the Company with respect to the Divestiture shall be
         included in Adjusted Net Debt, and (y) the total amount of the budgeted
         EBITDA for the divested assets or business for all periods of the
         calendar year subsequent to the Divestiture shall be included in
         Adjusted EBITDA.

                  For purposes of this Agreement only, the MVPSE shall be
determined within ninety (90) days after the end of each calendar year or at
such other date as may be necessary to calculate MVPSE for purposes of this
Agreement.

               (e) Percentage Release from Repurchase Option. If the MVPSE is,
as of a Target Date, less than the applicable Target MVPSE, but is greater than
ninety percent (90%) of the applicable Target MVPSE as of such Target Date, a
percentage of the Performance Vested Shares available for release from the
Repurchase Option as of such Target Date shall be released from the Repurchase
Option according to the following proportionate release schedule:

                                       4
<PAGE>   5

<TABLE>
<CAPTION>

                     Actual MVPSE as a                                       Percentage of Performance
                Percentage of Target MVPSE                                     Vested Shares Released
                --------------------------                                     ----------------------
<S>                                                                          <C>
                           90.0%                                                         0%
                           92.5%                                                        25%
                           95.0%                                                        50%
                           97.5%                                                        75%
                           100%                                                        100%.
</TABLE>

The percentage of Performance Vested Shares released shall be prorated for
one-half percentage increases between the MVPSE percentages shown (e.g., if the
MVPSE is at least 90.5%, but less than 91.0%, of Target MVPSE, 5% of the
Performance Vested Shares available for release from the Repurchase Option as of
the Target Date would be released from the Repurchase Option).

          (f) "Clawback" Rights. Notwithstanding any other provision of this
Section 3, if the MVPSE is less than the applicable Target MVPSE on any Target
Date (a "Prior Unsatisfied Target"), but thereafter the MVPSE equals or exceeds
the applicable Target MVPSE on any subsequent Target Date prior to December 31,
2005, all Performance Vested Shares which have not been previously released from
the Repurchase Option with respect to all Prior Unsatisfied Targets occurring
prior to such subsequent Target Date shall thereupon be released from the
Repurchase Option. As an example, if the Purchaser had earned release of 0% and
0% of the Performance Vested Shares as of December 31, 2000 and 2001,
respectively, and the MVPSE was equal to $950.00 on December 31, 2002, then (A)
100% of the Performance Vested Shares scheduled for release as of December 31,
2002, would be released from the Repurchase Option; and (B) 100% of the
Performance Vested Shares scheduled for release as of December 31, 2000 and
2001, would be released from the Repurchase Option. As a further example, if the
Purchaser had earned release of 0% and 0% of the Performance Vested Shares as of
December 31, 2000 and 2001, respectively, and the MVPSE was equal to $872.00 on
December 31, 2002, then (A) 25% of the Performance Vested Shares scheduled for
release as of December 31, 2002, would be released from the Repurchase Option
and (B) no additional Performance Vested Shares scheduled for release as of
December 31, 2000 or 2001, would be released from the Repurchase Option.

          (g) Termination of Repurchase Option. Any Performance Vested Shares
that are not released from the Repurchase Option according to the foregoing
provisions of this Section 3 shall be released from the Repurchase Option on
December 31, 2009, so long as the Purchaser is an employee of the Company on
such date.

          (h) Acceleration Event.

                 (i) An "Acceleration Event" shall occur in the event of a
         Change of Control of the Company, as such term is defined in the
         Indenture dated as of the date hereof between the Company and The Bank
         of New York, as trustee, as amended, modified or supplemented from time
         to time.

                                       5
<PAGE>   6

                 (ii) If an Acceleration Event occurs on or before January 1,
         2001, all Time Vested Shares shall be released from the Repurchase
         Option immediately prior to the Acceleration Event.

                 (iii) If an Acceleration Event occurs on or before December 31,
         2005, some or all of the Performance Vested Shares that have not been
         released from the Repurchase Option (because the Target Dates and/or
         Target MVPSE have not yet been reached) shall be released from the
         Repurchase Option immediately prior to the Acceleration Event in an
         amount equal to the average percentage of Performance Vested Shares
         that have been released from the Repurchase Option up to the date of
         the Acceleration Event multiplied by the total number of Performance
         Vested Shares then subject to the Repurchase Option, taking into
         account the effect of Section 3(f). Further, for purposes of
         calculating the MVPSE in connection with an Acceleration Event, Target
         MVPSE shall be prorated to the end of the calendar month immediately
         prior to the Acceleration Event. For example, if the Purchaser had
         earned release of 0% and 80% of the Performance Vested Shares as of
         December 31, 2000 and 2001, respectively, and an Acceleration Event
         occurred in July, 2002, and the actual MVPSE was equal to $807.00,
         then (A) the Target MVPSE would be prorated to June 30, 2002, pursuant
         to this Section 3(h) ($754.70 + [.50 x ($943.40 - $754.70)] =
         $849.05); (B) the June 30, 2002, actual MVPSE as a percentage of the
         prorated Target MVPSE as of December 31, 2002, would be 95%; (C)
         therefore, 50% of the Performance Vested Shares scheduled for release
         as of December 31, 2002, would be released from the Repurchase Option,
         pursuant to Section 3(e), immediately prior to the Acceleration Event;
         and (D) immediately prior to the Acceleration Event, 43.33% [(0 + 80 +
         50) / 3 = 43.33] of the Performance Vested Shares scheduled for
         release from the Repurchase Option based on the MVPSE as of December
         31, 2003, 2004 and 2005, would be released from the Repurchase Option,
         all for the immediate benefit of the Purchaser. As a further example,
         if the Purchaser had earned release of 0% and 0% of the Performance
         Vested Shares as of December 31, 2000 and 2001, respectively, and an
         Acceleration Event occurs in July, 2002, and if the actual MVPSE is
         $875.00, then (A) the Target MVPSE as of June 30, 2002 would be
         prorated to June 30, 2002, pursuant to this Section 3(h) ($849.05) (B)
         the June 30, 2002, actual MVPSE as a percentage of the prorated Target
         MVPSE as of December 31, 2002, would be 103%; (C) 100% of the
         Performance Vested Shares scheduled for release as of December 31,
         2002, would be released from the Repurchase Option pursuant to Section
         3(e), immediately prior to the Acceleration Event; and (D) taking into
         account the effect of Section 3(f), and immediately prior to the
         Acceleration Event, 100% of the Performance Vested Shares scheduled
         for release from the Repurchase Option based on the MVPSE as of
         December 31, 2003, 2004 and 2005, would be released from the
         Repurchase Option, all for the immediate benefit of the Purchaser. If
         an Acceleration Event occurs after December 31, 2005, no additional
         Performance Vested Shares shall be released from the Repurchase Option
         pursuant to this Section 3(h). The Company may exercise the Repurchase
         Option effective as of the time of an Acceleration Event with respect
         to any Performance Vested Shares that are not released from the
         Repurchase Option, regardless of whether or not a termination of
         employment occurs.

                                       6
<PAGE>   7

               (i) Fractional Shares. Notwithstanding any other provisions of
this Agreement, no fractional shares shall be released from the Repurchase
Option until a number of such fractional shares accumulate to equal one share.

               (j) No Share which is released from a Repurchase Option hereunder
shall thereafter be subject to the Repurchase Option without the prior written
consent of the Purchaser.

          SECTION 4. STOCKHOLDERS' AGREEMENT; RESTRICTIONS ON TRANSFER.

              (a) The Company and the Purchaser acknowledge and agree that the
Shares are subject to and restricted by the Stockholders' Agreement dated as of
the date hereof, among the Company and the stockholders of the Company signatory
thereto, as amended, modified or supplemented from time to time (as amended, the
"Stockholders' Agreement"), and with respect to such Shares, the Purchaser shall
be a "Management Stockholder" as such term is used in the Stockholders'
Agreement.

              (b) Notwithstanding anything to the contrary contained in the
Stockholders' Agreement, the Purchaser may not sell, assign, encumber, dispose
of or otherwise transfer (including any transfer by operation of law) any
interest in any Shares that have not been released from the Repurchase Option
other than a transfer to Sorensen Capital, LLC, provided that Sorensen Capital,
LLC agrees to be bound by all of the terms and provisions of this Agreement, the
Promissory Note and the Pledge Agreement dated as of the date hereof between the
Company and the Purchaser (the "Pledge Agreement").

          SECTION 5. EMPLOYMENT AGREEMENT.

                  The parties agree that the option provided to the Purchaser
under Section 6(c) of the Employment Agreement may not be exercised with respect
to any of the Shares purchased under this Agreement until January 1, 2006.

          SECTION 6.  REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

                  The Company represents and warrants to the Purchaser, as of
the date hereof, as set forth below.

              (a) The Company is a duly organized and validly existing
corporation under the laws of the State of Utah and has the corporate power and
the corporate authority to execute and deliver this Agreement and to perform its
obligations as specified in this Agreement.

               (b) The Shares have been duly authorized by the Company and, upon
receipt of the Purchase Price, will be validly issued, fully paid and
nonassessable.

              (c) This Agreement has been duly authorized by the Board of
Directors of the Company and has been executed and delivered by the Company.

              (d) The execution and delivery by the Company of, and the
performance by the Company of its obligations under, this Agreement do not
contravene any provision the Restated Charter or By-laws of the Company or any
agreement or other instrument binding upon the


                                       7
<PAGE>   8

Company that is material to the Company, or any judgment, order or decree of any
court or governmental authority having jurisdiction over the Company, and no
material consent, approval, authorization or order of, or qualification with,
any governmental authority is required for the performance by the Company of its
obligations under this Agreement, except such approvals as have been obtained
and are in full force and effect.

             (e) Assuming that the representations and warranties of the
Purchaser contained in this Agreement are true and correct, the offer, sale and
delivery of the Shares in the manner contemplated by this Agreement is exempt
from registration under the Securities Act of 1933, as amended (the "Securities
Act").

          SECTION 7. REPRESENTATIONS AND WARRANTIES OF THE PURCHASER.

                  The Purchaser represents and warrants to the Company, as of
the date hereof, as set forth below.

             (a) The execution and delivery by the Purchaser of, and the
performance by the Purchaser of its obligations under, this Agreement, the
Promissory Note, the Pledge Agreement and the other documents delivered in
connection therewith, do not contravene any provision of applicable law or any
agreement or other instrument binding upon the Purchaser that is material to the
Purchaser, or any judgment, order or decree of any court or governmental
authority having jurisdiction over the Purchaser, and no material consent,
approval, authorization or order of, or qualification with, any governmental
authority is required for the performance by the Purchaser of its obligations
under this Agreement, except such approvals as have been obtained and are in
full force and effect.

              (b) The Purchaser is an executive officer of the Company and has
received all of the information concerning the Company, the Common Stock and any
other matters relevant to his decision to purchase the Shares that he has
requested.

              (c) The Purchaser, as a result of his position as an executive
officer of the Company, is an "accredited investor" within the meaning of Rule
501 of Regulation D under the Securities Act.

              (d) The Purchaser is experienced in evaluating and making
speculative investments, and has the capacity to protect his interest in
connection with the acquisition of the Shares. In addition, the Purchaser has
such knowledge and experience in financial and business matters that he is
capable of evaluating the merits and risks of this investment.

              (e) The Purchaser is purchasing the Shares for his own account,
for investment purposes only and not with a view to any public sale or
distribution thereof.

              (f) The Purchaser understands that (i) the Shares have not been
and will not be registered by the Company under the Securities Act, the Utah
Uniform Securities Act or the securities laws of any other jurisdiction and will
be considered "restricted securities" under the Securities Act, (ii) the Shares
will bear the legends set forth in Section 9, (iii) the Company has no
obligation to register the Shares under the Securities Act or any state
securities law, and (iv) the Purchaser will not sell, transfer, hypothecate or
otherwise dispose of any Shares other than in


                                       8
<PAGE>   9

accordance with (A) the provisions, or exemptions therefrom, of the Securities
Act and the rules and regulations promulgated thereunder and the securities laws
of all other applicable jurisdictions and (B) the Stockholders' Agreement and
(C) this Agreement.

          (g) The Purchaser understands that the Company will rely upon the
accuracy and truth of the representations and warranties of the Purchaser set
forth in this Section 7, and the Purchaser hereby consents to such reliance.

        SECTION 8. TAX ELECTION.

                  THE PURCHASER ACKNOWLEDGES THAT IT IS THE PURCHASER'S SOLE
RESPONSIBILITY, AND NOT THE COMPANY'S, TO DECIDE IF AN ELECTION UNDER SECTION
83(B) OF THE INTERNAL REVENUE CODE SHOULD BE MADE AND TO FILE TIMELY SUCH
ELECTION, EVEN IF THE PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVES TO
MAKE THIS FILING ON HIS BEHALF.

        SECTION 9. STOCK LEGENDS.

                In addition to any legend required by the Stockholders'
Agreement, certificates representing the Shares shall bear the following
additional legend:

                  "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE
                  TERMS AND CONDITIONS OF, AND RESTRICTIONS ON TRANSFER SET
                  FORTH IN, A RESTRICTED STOCK PURCHASE AGREEMENT, DATED AS OF
                  MAY 31, 2000, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF
                  THE COMPANY, AND SUCH SHARES MAY NOT BE SOLD, ASSIGNED,
                  TRANSFERRED, PLEDGED, HYPOTHECATED, ENCUMBERED, OTHERWISE
                  GRANTED AS SECURITY, OR OTHERWISE DISPOSED OF, OTHER THAN IN
                  ACCORDANCE THEREWITH."

        SECTION 10. FURTHER AGREEMENTS.

                  The Company and the Purchaser hereby agree to execute, deliver
and record or cause to be executed, delivered and recorded such further
instruments, and take such other actions, as may be reasonably required to
effectuate the transactions contemplated by this Agreement.

        SECTION 11. SURVIVAL.

                  The respective representations, warranties, covenants and
agreements made by the Company and the Purchaser in this Agreement shall survive
the payment of the Purchase Price and the delivery of the Shares
(notwithstanding any investigation made by or on behalf of any party to this
Agreement).

                                       9
<PAGE>   10

           SECTION 12. SUCCESSORS AND ASSIGNS.

                  Subject to Section 4 hereof, this Agreement shall inure to the
benefit of and be binding upon the Company, the Purchaser and their respective
successors and permitted assigns. Nothing expressed in this Agreement is
intended or shall be construed to give any person other than the persons
referred to in the preceding sentence any legal or equitable right, remedy or
claim under or in respect of this Agreement. Except as specified in Section 4,
neither this Agreement nor any of the rights, interests or obligations hereunder
shall be assigned or delegated by any party hereto without the prior written
consent of the other party.

           SECTION 13. SEVERABILITY.

                  Any covenant, provision, agreement or term of this Agreement
that is prohibited or is held to be void or unenforceable in any jurisdiction
shall, as to such jurisdiction, be ineffective to the extent of such prohibition
or unenforceability without invalidating the remaining provisions of this
Agreement.

           SECTION 14. MODIFICATIONS, AMENDMENTS AND WAIVERS.

                  At any time subsequent to the date hereof, (a) the parties
hereto may, by written agreement, modify, amend or supplement any term or
provision of this Agreement and (b) any term or provision of this Agreement may
be waived by the party which is entitled to the benefits thereof. No course of
dealing among the parties or delay in exercising rights and remedies shall
operate as a waiver of such rights and remedies.

           SECTION 15. GENERAL MATTERS.

              (a) This Agreement constitutes the entire agreement and
understanding of the parties to this Agreement with respect to the matters and
transactions contemplated by this Agreement and supersedes all prior agreements
and understandings whatsoever relating to such matters and transactions. The
headings in this Agreement are for the purpose of reference only and shall not
limit or otherwise affect the meaning hereof. This Agreement may be executed in
counterparts, each of which shall constitute an original, but all of which shall
together constitute one instrument.

              (b) The Option Cancellation and Restricted Stock Purchase
Agreement dated as of February 22, 1999, between the Purchaser and the Company,
as amended, modified or supplemented from time to time, is hereby terminated in
its entirety with no further force or effect.

           SECTION 16. GOVERNING LAW.

                  This Agreement shall be governed by, and construed in
accordance with, the laws of the State of Utah.

                                       10
<PAGE>   11

           SECTION 17. NOTICES.

                  All notices, requests, demands, claims and other
communications hereunder shall be in writing and sufficient if delivered in
accordance with the provisions set forth in the Stockholders' Agreement.

           SECTION 18. COUNTERPARTS AND FACSIMILE EXECUTION.

                  This Agreement may be executed in two or more counterparts,
all of which shall be considered one and the same agreement and shall become
effective when one or more counterparts have been signed by each of the parties
and delivered (by facsimile or otherwise) to the other party, it being
understood that all parties need not sign the same counterpart. Any counterpart
or other signature to this Agreement that is delivered by facsimile shall be
deemed for all purposes as constituting good and valid execution and delivery by
such party of this Agreement.

           SECTION 19. WAIVER OF JURY TRIAL.

                  EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES ALL RIGHT
TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
RELATING TO THIS AGREEMENT.

           SECTION 20. MUTUAL CONTRIBUTION.

                  The parties to this Agreement and their counsel have mutually
contributed to its drafting. Consequently, no provision of this Agreement shall
be construed against any party on the ground that one party drafted the
provision or caused it to be drafted.

                                    ********


                                       11
<PAGE>   12


                  IN WITNESS WHEREOF, the parties hereto have executed and
delivered this Restricted Stock Purchase Agreement as of the date first written
above.

                                        HUNTSMAN PACKAGING
                                        CORPORATION

                                        By:/s/ RICHARD P. DURHAM
                                           ----------------------------------
                                           Name: Richard P. Durham
                                           Title: Chief Executive Officer


                                        PURCHASER
                                        /s/ SCOTT K. SORENSEN
                                        -------------------------------------
                                        Scott K. Sorensen


<PAGE>   13
                                                                       EXHIBIT A


                            SECURED PROMISSORY NOTE

                                (FULL RECOURSE)
$3,261,129                                                          May 31, 2000
                                                            Salt Lake City, Utah

     FOR VALUE RECEIVED, the undersigned, SCOTT K. SORENSEN (the "Maker"),
promises and agrees to pay to the order of HUNTSMAN PACKAGING CORPORATION
("HPC"), at 500 Huntsman Way, Salt Lake City, Utah 84108, or at such other place
as the holder hereof may designate in writing, the principal sum of THREE
MILLION TWO HUNDRED SIXTY-ONE THOUSAND ONE HUNDRED AND TWENTY-NINE ($3,261,129),
together with interest, compounded annually, on the unpaid balance thereof at
the rate of seven percent (7.0%) per annum from the date hereof until paid in
cash.  For the period prior to May 31, 2006, interest may, at the option of the
Maker, not be paid in cash but be added to the principal hereof on each
anniversary of the date of the original issuance hereof (the "PIK Option").
Principal and accrued interest outstanding under this Promissory Note (this
"Note") as of May 31, 2006 (including through the exercise of the PIK Option),
shall be paid in cash in three equal annual installments on each of (1) May 31,
2006, (2) May 31, 2007, and (3) May 31, 2008.  Interest accruing on the unpaid
principal of this Note (including through the exercise of the PIK Option) for
the period commencing June 1, 2006, through final maturity, shall be paid on May
31, 2007, and at final maturity in cash.  Prepayments shall be applied first
toward the payment and satisfaction of accrued and unpaid interest, and the
remainder shall be applied toward the reduction of principal.  Principal and
interest (except pursuant to the PIK Option) shall be payable only in lawful
money of the United States of America.

     This Note has been made in accordance with that certain Restricted Stock
Purchase Agreement, dated as of the date hereof (the "Restricted Stock
Agreement"), between HPC and the Maker.  For so long as any amounts of principal
or interest under this Note shall remain unpaid, upon the transfer of any of the
Shares except for a transfer of Shares to any Permitted Transferee (as defined
in the Stockholders' Agreement) or upon the exercise of any party of the rights
set forth in Section 6 of the Employment Agreement dated as of the date hereof
between the Maker and HPC, the lesser of (a) the total amount of any cash paid
in consideration of the transfer of the Shares, net of any expenses reasonably
incurred in connection with such transfer (the "Net Proceeds") or (b) the total
amount of all unpaid principal and interest under this Note (as of the
applicable payment date), shall be paid to the holder of this Note within three
(3) business days of the date the Net Proceeds are received by or on behalf of
the Maker.  Any payments made in accordance with this paragraph shall be
prepayments and shall be treated as specified in the following paragraph.

     The Maker may prepay at any time the obligations hereunder, in whole or in
part, without penalty.  The Maker, at his option, may pay amounts in excess of
the annual payments called for herein.  Such excess amounts shall be applied
either to reduction of the principal balance hereof or in prepayment of
designated future annual payments, at the election of the Maker, which election
must be made in writing at the time the excess amount is paid.  If the election
is to apply to the excess amount against future annual payment(s), the Maker
must designate the particular annual payment(s) which are being paid in advance.
If the Maker makes no timely election, excess amounts shall be applied in
reduction of the principal balance hereof in inverse order of maturity.  If the
excess amount is applied in reduction of the principal balance hereof (whether
by reason of election or otherwise), the payment shall not postpone or suspend
the obligation of the Maker to make the annual payments called for herein.

<PAGE>   14
     The occurrence of any of the following constitutes an "Event of Default":

     (a) The Maker fails to make any payment hereunder when due or within
fifteen (15) days thereafter;

     (b) the Maker defaults in the performance of any covenant or agreement
contained herein, in the Restricted Stock Agreement (other than a covenant or
agreement to make payments hereunder) or in the Pledge Agreement dated as of the
date hereof between the Maker and HPC;

     (c) a petition is filed seeking that the Maker be adjudged bankrupt;

     (d) the Maker makes a general assignment for the benefit of creditors;

     (e) the Maker suffers the appointment of a receiver; or

     (f) the Maker becomes insolvent.

Upon the occurrence of an Event of Default, the entire remaining unpaid balance
of both principal and interest owing hereunder shall, at the option of the
holder hereof and without notice or demand, become immediately due and payable.
Thereafter said unpaid principal balance and interest shall, until paid and both
before and after judgment, earn interest at the rate of ten percent (10%) per
annum.  The acceptance of any installment or payment after the occurrence of an
Event of Default shall not constitute a waiver of the holder's right of
acceleration with respect to such Event of Default or any subsequent Event of
Default.

     In the event any payment under this Note is not made at the time and in the
manner required, the Maker agrees to pay all costs and expenses (regardless of
the particular nature thereof and whether incurred with or without suit or
before or after judgment) which may be incurred by the holder hereof in
connection with the enforcement of any of its rights under this Note, including
court costs and attorneys' fees.

     The Maker hereby acknowledges the security interests granted by the Maker
to HPC pursuant to the terms of the Pledge Agreement dated as of the date hereof
between the Maker and HPC.

     Any notice or demand hereunder shall be made in accordance with the
provisions set forth in the Restricted Stock Agreement.

     The Maker expressly agrees that this Note, or any payment hereunder, may be
extended without notice from time to time by the holder hereof without in any
way affecting the liability of the Maker. This Note is a full recourse
promissory note and shall be the joint and several obligation of all makers,
sureties, guarantors and endorsers, and shall be binding upon their respective
heirs, personal representatives, successors and assigns.

     This Note shall be governed by and construed in accordance with the laws of
the State of Utah.

     Capitalized terms used herein and not otherwise defined shall have the
respective meanings set forth in the Restricted Stock Agreement.

                                    ********


     IN WITNESS WHEREOF, the undersigned Maker has executed this Note as of the
date first written above.

                                                  ------------------------------
                                                  Scott K. Sorensen