You might appeal to their corporate marketing program instead of to the philanthropy area. If you can help a company get positive publicity, favorable media coverage, etc., then they can treat the donation as an advertising cost. The marketing department usually has a much bigger budget than the donations committee does. Make sure the results are not just one-time. Give them good PR in your annual report, at the AGM, on signs at events, etc., so you are building a long term relationship with an expectation of annual partnerships/donations.