Document OzbVgzdR4oQQL5kYpzzgn71nX

DETERMINATION OF 60 SPECULAR GLOSS OF CLEAR COATINGS METHOD NUMMR WC-98-K-1; (T22-265-20) ISSUE PACE OP 1 PURPOSE AND LIMITATIONS This method describes a proce DATE dure for the determination of 60 specular gloss of clear coatings cast from dispersions March 23, 1900 of vinyl resins. This procedure is designed to minimize the influence of film characteristics other than the coating surface on the gloss measurement. This method is primarily intended for, although not limited to, clear coatings. 2 EQUIPMENT a) Gardner 60 Specular Gloss Head, manufactured by Gardner Laboratory, Inc., Betbesda 14, Maryland, or equivalent. b) Gardner Automatic Photometric Unit, manufactured by Gardn r Laboratory, Inc., or equivalent, and modified to includ a neon warning-light to indicate when the unit's motor is out of electrical balance. Install' the neon light as indicated in the schematic drawing, Figure 1, given in1 Plastics Standard Testing Method WC-98-K; (22-265-8). Th clutch between the motor and dial sometimes gets out of adjustment, resulting in possible faulty readings. When an electrical unbalance exists, the neon light goes "on"; it goes "off" when balance is restored. NOTE: Do not take a reading when the light is "on". c) Polished black glass reference standard (value - approxi mately 94) d) Two ceramic tile standards (values - approximately 42 and 21, respectively) e) Aluminum panels, 0.020 by 3 by 4 inches, Type 3003, Temp r Bright, one side flat, (no holes), coated with a flat black paint having essentially zero gloss; supplied by Mutual Manufacturing Supply, Cincinnati, Ohio. f) Small coating bar for casting film on panel. g) Constant temperature block as shown in Figure 1, or equiva lent. The block is to be mounted on any variable laboratory heater such as the Speedi-Heet Duplex with Powerstat Control manufactured by Labline, Inc., and the Fenwall switch in the block wired into the heater circuit to c ntrol the temperature of the block. The vacuum part may be connected to any source of vacuum such as a water pump, and the vacuum applied to hold the aluminum panels in close contact with the heating block. WC-98-K-1, ISSUE 1; (T22-265-20) p2 of 4 4-3 /4H PLASTICS STANDARD TESTING METHOD ) Reference: Union Carbide Chemicals Company, Development Department, LD 2644 and LD 2645 FIGURE 1, HEAT STABILITY BLOCK HOT PLATE PLASTICS STANDARD TESTING METHOD p3 of 4 WC-ya-K-1, ISSUE 1; (T22-265-20) 3 PREPARATION OF TEST SPECIMEN a) On an aluminum panel, coated with a flat black paint to provide a surface of nearly zero gloss, cast a film of the sample resin dispersion to obtain a film approximat ly 0.010 inch in thickness after fusion. b) Heat the aluminum panel with the test specimen for five minutes at 350F, remove the panel from the heating block, or equivalent, and place it on a cool surface, such as a bench top which will not be marred by the hot panel. Allow the panel to cool to room temperature. 4 PROCEDURE a) Attach the Gardner 60 Specular Gloss Head to the Gardner Automatic Photometric Unit by means of the multiple plug. b) Turn on the light and motor switches. (The photometric unit should be left plugged in at all times. The amplifi r is operating under this condition and no warm-up period is required.) Keep the switch on the 60 Specular Gloss H ad in the "off" position. The "1-10" switch on the photo metric unit should be in the "1" position. c) Aim the sample part of 60 Specular Gloss Head at the floor, and adjust the Duo-dial to zero by means of the "1" Zero Adjust Knob. d) Place the 60 Specular Gloss Head over the polished black glass standard, and adjust the Duo-dial to read the valu marked on the back of the standard (approximately 94) by means of the adjustment screw on the Gloss Head. Fine adjustment is accomplished with the "Balance Knob" on the automatic photometric unit. e) Place the Search Head over one of the ceramic tile standards The Duo-dial should record the value of this standard within 1 per cent. If it fails to do so, the instrument should be readjusted. If the reading is still incorrect after the readjustment, the optical adjustment of the instrument should be checked. The optical geometry must be as specified in ASTM Method D 523-53T. f) Place the 60 Specular Gloss Head over the test specimen, and record the maximum Duo-dial reading as the gloss. g) If the reading is greater than 100, make the gloss deter mination as follows: 1) Place the Search Head over the polished black standard and set the Duo-dial to read one-half of the stated value of the standard (1/2 of 94 - 47). 2) Check the adjustment against a second standard as described in paragraphs a through f. 3) Determine the Duo-dial reading for the test specimen. Multiply this value by 2, and record the result as the gloss of the sample. h) Make three determinations on each specimen and report their average as the gloss value. WC-98-K-1. ISSUE 1 (T22-265-20) p4 of 4 PLASTICS STANDARD TESTING MEvT-H;-O--D- 5 REPORT a) Complete sample identification b) Analyst and date c) Gloss value; average of three readings 6 REFERENCE D-3385-151 DEVELOPMENT DEPARTMENT TECHNICAL CENTER South Charleston, West Virginia