| 摘要 |
1,177,703. Uses of luminescence. MAGNAFLUX CORP. 1 Aug., 1967 [27 June, 1967], No. 35348/67. Heading C4S. [Also in Division H1] Aggregates for detecting flaws each comprise a core of adhering magnetic and fluorescent particles encapsulated in a resin. The aggregates are made by mixing magnetic and fluorescent powders to form the cores, dissolving the resin in a water-miscible volatile solvent, adding the cores to form a slurry then adding water to precipitate the resin as a coating, on the cores. Magnetic powders are Fe 2 O 3 , Fe 3 O 4 , carbonyl iron and ferrites. Fluorescent powders comprise particles of a melamine- or benzoguanamine - sulphonamide - formaldehyde resin containing a fluorescent dye, e.g. 2,2-dihydroxy 1,1-naphthalolazine together with fluoranthane to increase fluoresence. The coating resin may be a thermoplastic polyamide derived from the reaction of dimerized linoleic acid and a polyamine, e.g. ethylene diamine of molecular weight 6000-9000 and a melting point of 105‹ to 115‹ C. The solvents include methanol, ethanol, n-propanol, isopropanol, butanol, methyl ethyl ketones and acetone. The aggregates having a particle size of 3 to 75 microns are used as a suspension in oil or water.
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