<PAGE>   1

                                                                 EXHIBIT 10.25

                                Promissory Note



$350,000                                         Dated as of December 12, 1996

      For value received, Clean Room Products Inc., a New York corporation (the
"Borrower"), promises to pay to the order of Boca Raton Capital Corporation, a
Florida corporation (the "Lender"), at such times and in such amounts as
hereinafter set forth, at the principal office of the Lender at Boca Raton
Capital Corporation, 6516 Via Rosa, Boca Raton, Florida 33433, the principal sum
of ($350,000), in lawful money of the United States of America, and to pay
interest on the unpaid principal balance hereof in like money at such office
from the date hereof until the principal hereof shall have become due and
payable by acceleration or otherwise, at the rate per annum set forth below. The
principal amount of this Note together with all accrued and unpaid interest
hereon shall be due and payable on April 30, 1997. Interest on this Note shall
be computed at a fixed rate per annum equal to the rate of interest as announced
from time to time by Citibank, N.A. (the "Prime Rate") as of the date this Note
is executed, plus one percent (1%). Interest at the foregoing rate shall be
calculated on the basis of a 360-day year for the actual number of days elapsed
(i.e. 1/360th of a full year's interest shall accrue for each day that any
principal balance is outstanding under this Note). The unpaid principal balance
of this Note may be prepaid at any time without premium or penalty. In the event
that any Event of Default (as hereinafter defined) shall have occurred and be
continuing, the rate of interest during such period shall be computed at the
Prime Rate as of the date this note is executed plus five percent (5%).

      This Note is the Note referred to in the Agreement and Plan of Merger and
Reorganization (the "Merger Agreement") dated as of December ____, 1996 made
between the Borrower and the Lender. Capitalized terms used herein and not
defined shall have the same meanings when used herein as in such Merger
Agreement.

      The Borrower agrees to pay all costs incurred by any holder hereof,
including reasonable attorneys' fees (including those for appellate
proceedings), incurred in connection with any collection or attempted collection
or enforcement hereof.

      In the event that any of the following events shall occur, each of which
shall constitute a default hereunder (an "Event of Default"), all liabilities of
the Borrower to the Lender evidenced by this Note shall become due and payable
three (3) days after written notice is provided by the Lender to the Borrower
except as set forth in clause (6) of this paragraph: (1) failure by the Borrower
to pay any amount owed hereunder, within five (5) business days of the time when
and as the same shall become due and payable, whether at the due date thereof or
at a date fixed for payment thereof or by acceleration thereof or otherwise; (2)
failure by the Borrower to perform or comply with any obligation, promise,
agreement or provision under this Note; (3) the dissolution or liquidation of
the Borrower, (4) a decree or order shall be entered by a court for relief in
respect of the Borrower under
<PAGE>   2

Title 11 of the United States Code, as now or hereafter constituted, or any
other applicable Federal or state bankruptcy, insolvency or other similar law,
or appointing a receiver, liquidator, assignee, trustee, custodian, sequestrator
(or similar official) of the Borrower or of any substantial part of its
property, or ordering the winding-up or liquidation of its affairs and the
continuance of any such decree or order unstayed and in effect for a period of
sixty (60) consecutive days; (5) the Borrower shall file a petition or answer or
consent seeking relief under Title 11 of the United States Code, as now or
hereafter constituted, or any other applicable Federal or state bankruptcy,
insolvency or other similar law, or consent to the institution of proceedings
thereunder or to the filing of any such petition or to the appointment or taking
possession of a receiver, liquidator, assignee, trustee, custodian, sequestrator
(or other similar official) of the Borrower or any substantial part of its
property, or the Borrower shall fail generally to pay its debts as such debts
become due, or take corporate action in furtherance of any such action; or (6)
termination of the Merger Agreement; provided that in the event of a termination
of the Merger Agreement all liabilities of the Borrower evidenced by this Note
shall become due and payable three (3) months after the Merger Agreement is
terminated.

      All parties to this Note, including the Borrower and any sureties,
endorsers or guarantors, hereby waive presentment for payment, demand, protest,
notice of dishonor, notice of acceleration of maturity, and all defenses on the
ground of extension of time for payment hereof, and agree to continue and remain
bound for the payment of principal, interest and all other sums payable
hereunder, notwithstanding any change or changes by way of release, surrender,
exchange or substitution of any security for this Note or by way of any
extension or extensions of time for payment of principal or interest; and all
such parties waive all and every kind of notice of such change or changes and
agree that the same may be made without notice to or consent of any of them. The
rights and remedies of the holder as provided herein shall be cumulative and
concurrent and may be pursued singularly, successively or together at the sole
discretion of the holder, and may be exercised as often as occasion therefor
shall occur, and the failure to exercise any such right or remedy shall in no
event be construed as a waiver or release of the same.

      Anything herein to the contrary notwithstanding, the obligations of the
Borrower under this Note shall be subject to the limitation that payments of
interest to the Lender shall not be required to the extent that receipt of any
such payment by the Lender would be contrary to provisions of law applicable to
the Lender (if any) which limit the maximum rate of interest which may be
charged or collected by the Lender; provided, however, that nothing herein shall
be construed to limit the Lender to presently existing maximum rates of
interest, if an increased interest rate is hereafter permitted by reason of
applicable federal or state legislation. In the event that the Borrower makes
any payment of interest, fees or other charges, however denominated, pursuant to
this Note, which payment results in the interest paid to the Lender to exceed
the maximum rate of interest permitted by applicable law, any excess over such
maximum shall be applied in reduction of the principal balance owed to the
Lender as of the date of such payment, or if such excess exceeds the amount of
principal owed to the Lender as of the date of such payment, the difference
shall be paid by the Lender to the Borrower.


                                      2
<PAGE>   3

      THE BORROWER HEREBY, AND THE LENDER BY ITS ACCEPTANCE OF THIS NOTE,
KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVE THE RIGHT EITHER MAY HAVE TO A
TRIAL BY JURY IN RESPECT OF ANY LITIGATION BASED HEREON, OR ARISING OUT OF,
UNDER OR IN CONNECTION WITH THIS NOTE AND ANY AGREEMENT CONTEMPLATED TO BE
EXECUTED IN CONJUNCTION HEREWITH, OR ANY COURSE OF CONDUCT, COURSE OF DEALING,
STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OR EITHER PARTY. THIS
PROVISION IS A MATERIAL INDUCEMENT FOR THE LENDER MAKING THE LOAN EVIDENCED BY
THIS NOTE.

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

      IN WITNESS WHEREOF, the Borrower has caused this Note to be executed on
this December 12 day of 1996.

                                          CLEAN ROOM PRODUCTS, INC.


                                          By:  /s/ Paul Gerber
                                               ------------------
                                                Name: Paul Gerber
                                                Title: President


                                      3