| 摘要 |
<p>A time-colour indicator compsn. for visual indication of when an associated prod. has reached the end of its useful life comprises (a) a room temp. volatilisable, non-aq. liq. solvent (I), (b) an effective amt. of an indicator dye (II) which is non-volatile at room temp., the (II) being soluble in (I) and assuming a first colour when dissolved in the (I); and (c) an effective amt. of at least one proton-donating cpd. (III), the (II) assuming a second colour which is visually distinct from the first colour when the dye is in contact with only the (III). The ratio of (I) to (II) and (III) is such that upon evapn. of the (I), the (II) changes from the first colour to the second colour, this colour change indicating that the prod. has become ineffective.</p> |
