I agree that it's probably not always necessary to include the 系、but how about using "~based" if you'd rather add it in?

WATER-REDUCING AGENT FOR CEMENT - Patent JP03187960
CONSTITUTION: or a salt thereof ...
www.freepatentsonline.com/JP03187960.html -

For example, the description in the link above could be re-written as
"The water-reducing agent for cement contains *the formaldehyde condensate of 4-aminobenzene sulfonic acid as a base* "
or a variant of 'sulfonic acid-based' (although the description in this latter example would then be nowhere near as complete).

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Note added at 37 mins (2008-06-15 00:26:47 GMT)
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Sorry, the full link above should correctly read:
WATER-REDUCING AGENT FOR CEMENT - Patent JP03187960
CONSTITUTION: The water-reducing agent for cement contains as a main component the formaldehyde condensate of 4-aminobenzene sulfonic acid or a salt thereof ...
www.freepatentsonline.com/JP03187960.html -