================================================================================ SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5) ------------------------------ HERCULES INCORPORATED (Name of Issuer) COMMON STOCK, $25/48 STATED VALUE PER SHARE 427056106 (Title of class of securities) (CUSIP number) RICHARD A. WEINBERG, ESQ. C/O ISP MANAGEMENT COMPANY, INC. 1361 ALPS ROAD WAYNE, NEW JERSEY 07470 (973) 628-4000 (Name, address and telephone number of person authorized to receive notices and communications) WITH A COPY TO: STEPHEN E. JACOBS, ESQ. WEIL, GOTSHAL & MANGES LLP 767 FIFTH AVENUE NEW YORK, NEW YORK 10153-0119 (212) 310-8000 FEBRUARY 28, 2001 (Date of event which requires filing of this statement) If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of ss.ss. 240.13d-1(e), 240.13d-1(f) or 240.13d-(g), check the following box. [ ] Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. Seess. 240.13d-7 for other parties to whom copies are to be sent. * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purposes of Section 18 of the Securities Exchange Act of 1934 (the "Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act. (However, see the Notes.) (Continued on following pages) (Page 1 of 7 Pages) ================================================================================ NY2:\1019821\01\L%WD01!.DOC\54104.0018 ----------------------------------------------------------- -------------------------------------------------------- CUSIP No. 427056106 13D Page 2 of 7 Pages ----------------------------------------------------------- -------------------------------------------------------- ---------------------- ------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON ISP OPCO HOLDINGS INC. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON ---------------------- ------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [ ] (b) [X] ---------------------- ------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY ---------------------- ------------------------------------------------------------------------------------------------------- 4 SOURCE OF FUNDS: OO ---------------------- ------------------------------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware ---------------------- ------------------------------------------------------------------------------------------------------- 7 SOLE VOTING POWER: 0 NUMBER OF SHARES ------------------- ------------------------------------------------------------------------------- 8 SHARED VOTING POWER: 10,719,200 BENEFICIALLY OWNED BY ------------------- ------------------------------------------------------------------------------- EACH 9 SOLE DISPOSITIVE POWER: 0 REPORTING PERSON WITH ------------------- ------------------------------------------------------------------------------- 10 SHARED DISPOSITIVE POWER: 10,719,200 ---------------------- ------------------------------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON: 10,719,200 ---------------------- ------------------------------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES: [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 9.98% ---------------------- ------------------------------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON: CO ---------------------- ------------------------------------------------------------------------------------------------------- ----------------------------------------------------------- -------------------------------------------------------- CUSIP No. 427056106 13D Page 3 of 7 Pages ----------------------------------------------------------- -------------------------------------------------------- ---------------------- ------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON ISP INVESTMENTS INC. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON ---------------------- ------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [ ] (b) [X] ---------------------- ------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY ---------------------- ------------------------------------------------------------------------------------------------------- 4 SOURCE OF FUNDS: WC, OO ---------------------- ------------------------------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware ---------------------- ------------------------------------------------------------------------------------------------------- 7 SOLE VOTING POWER: 10,719,200 NUMBER OF SHARES ------------------- ------------------------------------------------------------------------------- 8 SHARED VOTING POWER: 0 BENEFICIALLY OWNED BY ------------------- ------------------------------------------------------------------------------- EACH 9 SOLE DISPOSITIVE POWER: 10,719,200 REPORTING PERSON WITH ------------------- ------------------------------------------------------------------------------- 10 SHARED DISPOSITIVE POWER: 0 ---------------------- ------------------------------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON: 10,719,200 ---------------------- ------------------------------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES: [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 9.98% ---------------------- ------------------------------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON: CO ---------------------- ------------------------------------------------------------------------------------------------------- ----------------------------------------------------------- -------------------------------------------------------- CUSIP No. 427056106 13D Page 4 of 7 Pages ----------------------------------------------------------- -------------------------------------------------------- ---------------------- ------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON INTERNATIONAL SPECIALTY PRODUCTS INC. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON ---------------------- ------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [ ] (b) [X] ---------------------- ------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY ---------------------- ------------------------------------------------------------------------------------------------------- 4 SOURCE OF FUNDS: OO ---------------------- ------------------------------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware ---------------------- ------------------------------------------------------------------------------------------------------- 7 SOLE VOTING POWER: 0 NUMBER OF SHARES ------------------- ------------------------------------------------------------------------------- 8 SHARED VOTING POWER: 10,719,200 BENEFICIALLY OWNED BY ------------------- ------------------------------------------------------------------------------- EACH 9 SOLE DISPOSITIVE POWER: 0 REPORTING PERSON WITH ------------------- ------------------------------------------------------------------------------- 10 SHARED DISPOSITIVE POWER: 10,719,200 ---------------------- ------------------------------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY REPORTING PERSON: 10,719,200 ---------------------- ------------------------------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES: [ ] ---------------------- ------------------------------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 9.98% ---------------------- ------------------------------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON: CO ---------------------- ------------------------------------------------------------------------------------------------------- This Amendment No. 5 ("Amendment No. 5") amends the statement of beneficial ownership on Schedule 13D ("Schedule 13D") filed on July 24, 2000, as amended by Amendment No. 1 filed on October 11, 2000, Amendment No. 2 filed on January 23, 2001, Amendment No. 3 filed on February 7, 2001 and Amendment No. 4 filed on February 20, 2001, by and on behalf of ISP Opco Holdings Inc. ("ISP Opco"), ISP Investments Inc. ("ISP Investments"), and International Specialty Products Inc. ("ISP" and together with ISP Investments and ISP Opco, the "Reporting Persons") with respect to their ownership of common stock, stated value $25/48 per share ("Common Stock"), of Hercules Incorporated (the "Company"). Capitalized terms used herein and not defined herein have the meanings ascribed thereto in the Schedule 13D, as previously amended. ITEM 4. PURPOSE OF TRANSACTION On February 28, 2001, Samuel J. Heyman, Chairman of the Board of ISP, sent the following letter to Mr. Thomas Gossage, Chairman, CEO and President of the Company: Mr. Thomas Gossage Chairman, CEO and President Hercules Incorporated Hercules Plaza 1313 North Market Street Wilmington, Delaware 19894-0001 Dear Tom: I was disappointed in your February 23rd letter and your Board's decision to reject ISP's compromise proposal. Contrary to your apparent belief, there is nothing inconsistent in our view with a shareholder being permitted to underscore its confidence in the underlying values of the Company by making an additional investment on the one hand and your "on going sale process" on the other. We are concerned with what seems to us Hercules' narrow, one-dimensional approach to maximizing shareholder values. If Hercules is unable to sell the Company on an advantageous basis, it will have needlessly deprived Hercules shareholders of the opportunity to decide for themselves whether to accept our previously proposed $17 1/2 tender offer or, under our compromise approach, sell their shares in the open market to ISP or any other shareholder wishing to acquire up to 20% of the Company's shares. This position is especially surprising given the multitude of takeover defenses the Company has erected and the fact that we have always been willing to address any of your legitimate concerns in the form of reasonable conditions with respect to our ownership position. With respect to your reference to the withdrawal of our proposed tender offer, as you know, the October offer expired by its own terms on account of the fact that your Board had refused to exempt it from its poison pill and related Delaware statutory provisions. That is why we put forward the compromise proposal to permit ISP to acquire up to 20% of Hercules' shares rather than 35%. While we can only assume that if your Board is unwilling to permit our acquisition of up to 20% of Hercules shares, it would not have gone 5 along with our 35% proposal either - but if we are missing something in this regard, please let us know. With regard to the last point in your letter, your claim that ISP's actions/statements are a hindrance to your efforts is sheer nonsense, as in point of fact we have been very patient and constructive shareholders for some time now. As you will recall, it was ISP who first encouraged Hercules to abandon its flawed restructuring strategy and sell the Company. While it took Hercules quite some time to adopt this strategy, we not only applauded the decision but have provided assurances, whether we were a 10%, 20%, or 35% owner, that we would support the sale of the Company at a fair price. In fact, despite your invitation, we have refrained from taking part in the auction process in large measure because we view our Hercules stake as an investment and so that there could be no claim that our participation, as the Company's major shareholder, would have a chilling effect on other interested bidders. Tom, you know that we have a high conviction concerning the way in which Hercules has conducted the Company's affairs in recent years. In this connection, we intend to bring these matters to the attention of Hercules shareholders at the Company's upcoming Annual Meeting. Moreover, as owners of more than 10.7 million Hercules shares, we will be seeking to elect a slate of directors, with a strong ownership orientation committed to the interests of Hercules shareholders, to replace the four incumbent directors up for re-election this year, who we understand (as of the last public filing) own in the aggregate less than 50,000 shares. Sincerely, /s/ Samuel J. Heyman * * * ISP INTENDS TO FILE A PRELIMINARY PROXY STATEMENT WITH THE U.S. SECURITIES AND EXCHANGE COMMISSION RELATING TO ISP'S SOLICITATION OF PROXIES FROM THE STOCKHOLDERS OF THE COMPANY FOR USE AT THE 2001 ANNUAL MEETING. ISP STRONGLY ADVISES ALL HERCULES STOCKHOLDERS TO READ THE PROXY STATEMENT WHEN IT IS AVAILABLE BECAUSE IT WILL CONTAIN IMPORTANT INFORMATION. INFORMATION RELATING TO THE PARTICIPANTS IN ISP'S PROXY SOLICITATION IS CONTAINED IN THE SOLICITING MATERIAL UNDER RULE 14a-12 FILED BY ISP WITH THE SEC ON FEBRUARY 7, 2001. INVESTORS CAN GET ISP'S PROXY STATEMENT WHEN IT IS AVAILABLE AND OTHER RELEVANT DOCUMENTS AT NO CHARGE ON THE SEC WEBSITE AT HTTP:\\WWW.SEC.GOV. [The remainder of this page intentionally left blank.] 6 SIGNATURES After reasonable inquiry and to the best of their knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct. Dated: February 28, 2001 ISP OPCO HOLDINGS INC. ISP INVESTMENTS INC. INTERNATIONAL SPECIALTY PRODUCTS INC. By: /s/ Richard A. Weinberg ----------------------------------------------- Richard A. Weinberg Executive Vice President, General Counsel and Secretary 7