Q panels

Fig. 2 demonstrates the light stability of a high-solid lacquer based on two-component polyurethane. The loss of gloss was measured as a function of the irradiation time in a QUV instrument (Q-Panel Company, Cleveland Ohio). The figure also shows that a particularly good... 

The photooxidation was carried out in a commercial weathero-meter (Q-UV, Q-panel Co., Cleveland, Ohio). This apparatus uses medium pressure mercury fluorescent UV lamps (Sunlamps F5-40, Westinghouse Electric Corp.) which emit UV light in the 273-378 nm range with a maximum intensity at 310 nm. 

Oligomer and Film Characterization. Brookfield viscosity measurements were taken on a Model RVTD digital readout viscometer. Samples for Instron testing were prepared on glass plates using 25 or 75 pm (1.0 or 3.0 mil) Byrd film applicator. Coatings for cure speed and MEK double rub (MEKDR) studies were prepared on aluminum Q-Panels using a 40 wire wound rod (100 pm or 4.0 mil). 

Test Panel Preparation. Grit-blasted, steel Q-panels, 3 x 5 in were stored in protective paper inside a desiccator. Just prior to use they were rinsed with a 1/1 (by volume) mixture of mineral spirits and methyl ethyl ketone, allowed to dry, then rinsed with methyl ethyl ketone. Coatings were applied with a brush and thinned to uniform thickness with a number 24 helically wound (Meyer) rod. 

Grit (AljOj) blasted mild steel Q panels, spray coated on both sides, were used for iron pick-up studies. Similar panels were used for chemical characterisation. 

The low metal loss figures for the chlorine containing vinyl acrylic system noted above were supported by analytical measurements of iron pick-up in coatings on grit blasted Q panels. Under constant immersion in 3J NaCl the iron pick-up, equivalent to 0.13 micron metal loss, remained virtually unchanged after 14 days over the 63 days exposure. However, the acrylic system had an equivalent metal loss of 0.55 micron at 14 days which increased steadily to 1.43 microns at 63 days. 

Chemical Characterisation. Chemical characterisation of the underfilra darkening beneath chlorine-containing vinyl-acrylic films was sought using a variety of techniques on the substrate surface as well as the backside of stripped films. The substrates were grit blasted and plain mild steel Q panels exposed up to 98 days in hot salt spray and examined within hours of removal. 

Materials. Reagent grade materials were used as received. The hexakis(methoxymethyl)melamine (HMMM) resin was Cymel 303 (American Cyanamid). Bonderite 1000 pretreated cold-rolled 3"x9"x2AGA steel panels (Parker) were used for enamel testing. Q-Panel Type DT 3"x6" 0.010" tin-plated steel panels were used for preparation of free films. 

Figure 22.6. Accelerated weather testing, (a) Xenon arc Fade-Ometer. (Courtesy of Atlas Electric Devices Company.) (b) Fluorescent lamp QUV accelerated weathering tester. (Courtesy of Q-Panel Company.) (c) Xenon arc Weather-Ometer. (Courtesy of Atlas Electric Devices Company.)...

Disc shaped samples similar to those used in the CO2 equipment were exposed to irradiation by UVA-340 tubes in a QUV Accelerated Weathering unit (Q-Panel Company). A constant temperature of 40°C was used. The samples were removed from the exposure chamber periodically to record FTIR transmission spectra in the 1700-1800 cm region. 

Figure 6 shows how a borosilicate filter will change its transmittance dramatically during the first 24 hours of operation and remain fairly stable thereafter. For this reason many manufacturers such as Atlas (17) and Q-Panel (18), among others, offer "preaged" for use in their equipment. This problem is not as critical for quartz filters so they are not "preaged." It is reported that LiO-BeO-SiO glasses do not solarize (3). 

Atlas Material Testing Technology LLC, 4114 N, Ravenswood Ave., Chicago, IL 60613. Q-Panel Lab Products, 800 Canterbury Road, Cleveland OH 44145. 

Q-Lab (formerly Q-Panel) (34) offers a fluorescent lamp photostability-testing unit, their QUV/cw unit, pictured in Figure 19. This unit, originally designed... 

Radiation Procedures The samples were irradiated at 40°C with either a QUV apparatus (Q-Panel Co., Cleveland, Ohio) which uses mercury fluorescent sunlamps (Westlnghouse FS-40) with an emission maximum at 313 nm, or a more Intense (by a factor of about 40) medium pressure mercury lamp (Hanovia) with an emission maximum at 366 nm. All irradiations were pyrex glass filtered. 

The total intensity of light emitted from the FS-40 lamps was estimated to be 2.1 x 10 moles of photons/cm sec. The intensity at 5 cm, measured by electronic spectroradlometer at the Q-Panel Company, is 18 ywatts corresponding to 4.7 x IQ-H moles of photons/cm sec. 

Figure 10.10 UV spectrum from sunlight at noon at Cleveland, Ohio, in June and December, compared vs ith the output from a fluorescent UVA tube (from the Q Panel Company, Cleveland).

Peel Test (PSTC-1) - Cold rolled steel "Q-Panels" (Q-PanelCo.) were used. A one-inch wide strip of coated Mylar is bonded to the panel under pressure of a 4 1/2-lb. roller. 

Pig. 17. Panel A shows a Cahn-Hilliard plot to estimate the effective diffusion constant Des from the intercept with the vertical axis for an isothermal crystallization experiment on iPP. The inset shows the R(q) vs q. Panel B shows similar plots obtained at different crystallization temperatures from 120 C (top curve) to 140°C (bottom curve) in steps of 5 C (31). 

For ultraviolet radiation (UV) and alternate ultraviolet radiation and condensation (UC) conditioning, the samples were kept in a QUV/Se weathering chamber (Q-Panel Lab Products, Cleveland Ohio). The samples were conditioned to UV radiation only and to alternate exposure to UV radiation for 4 hours followed by condensation for 4 hours. Phelps and Long [52] reported that thermal energy was sufficient to break bonds in cured epoxy, thus the temperature in the QUV chamber was elevated to provide accelerated degradation maintained at 60°C. The conditioning for this set was carried out for 5, 10 and 15 days. 

Materials. Caprolactone polyols (Tone 0201 Mn= 530, and Tone 0305 Mn= 540), cycloaliphatic diepoxide (UVR-6105), triarylsulfonium hexafluoroantimonates (UVI-6974) were provided by Union Carbide Corporation. Surfactant L-7604 was procured from Witco Corporation. Caprolactone polyols were dried and stored with molecular sieves (4A). Tetraethyl orthosilicate (TEOS, 98 %) and xylene (99 %) were purchased from Aldrich. Xylene was purified according to reported literature [3]. Aluminum panels were purchased from Q-Panel Lab Products. All the materials were used as received unless specified otherwise. 

Brennan, P. and Fedor, C. (1986) Sunlight, UV and accelerated weathering. The Q Panel Company, Cleveland, Ohio. 

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