Gloss value

The standard test method utilizes a light source directed toward the sample surface at a specified incidence angle (e.g., 60°). The angle used depends on whether it is a high-or low-gloss surface. The quantity of reflected light is measured by a photosensitive receptor and correlates to the gloss value of the film. 

Tests to measure fogging are specified in ASTM D5293. It measures the effect on the average gloss value of a glass plate that is fogged in the test. 

Haze and gloss test methods measure how well a material reflects and transmits light. They quantify characteristics such as clear and shiny. Although haze is appropriate for transparent or translucent materials, gloss can be measured for any material. Both gloss and haze tests are precise, but they are often used to measure appearance, which is more subjective. The correlation between haze and gloss values and how people rate the clarity or shininess of a plastic is uncertain. 

Polymer surface morphology will affect the value of gloss. Processing parameters as well as mold flnish (for various molding operations) or chill roll finish (in cast film operations) will also affect gloss values. Typically, rubber-modified polyolefins have a lower gloss than highly crystalline polyolefins. 

Single-coated, woodfree papers are generally calendered on-Hne. The machines used for this are mostly 2 x 2-roU soft calenders. At speeds up to 1300 m min Gardner gloss values of 55-65% can be achieved. To insure good flatness - this applies above aU to cut-size sheets - the papers must be subjected to only moderate linear loads. 

The appearance of black velvet corresponds to the measurement value, i.e. a gloss value of zero. 

Figure 5.51 Weathering behavior of polycarbonate with and without UV-protective layer (10 mm thick multi-wall PC sheet, weathering in the Xenon Weatherometer 102 18) [ 192] Left yellowing Right surface gloss value...

Sodium metasilicate. Used as a mill addition in enamels for aluminum. Improves working properties and gives higher gloss values. 

ISO 2813 2014 paints and varnishes— determination of gloss value at 20°, 60° and 85° Gloss of the monitor housing... 

A measure of the reflection haze of a specimen may be determined from the specular gloss values obtained at 20° (Gjo) and 60° (Gm). The haze index H is equal to G o - G2o- Repeatability by a single operator should be less than two haze index units. 

LLDPE with 30 weight percent COC has haze of less than 8 percent. Low haze values are usually paired with high gloss values, particularly with multilayer structures. Optics of COC-containing films is very competitive with ionomer and nylon films. 

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