Testing gloss

The use of standard panels according to ISO 1514 also has advantages. Standard panels are marketed by several companies. It is advantageous to use flat, inert substrates for optical and some mechanical tests if the reproduction of identical substrate surfaces presents serious difficulties (e.g., surfaces of wood or mineral substrates). For example, glass plates are used to test gloss and color polished steel sheets are used to test flexibility. 

Testing of lubricants is based on the determination of the flow behavior of plastic melts (capillary viscosi-metry, spiral flow test, demolding force, by plasto-graph, extrusiometer, melt strength, roll-mill tests, etc.) or by finished part testing (gloss and smoothness, slip measurements, determination of static friction, etc.). 

ASTM D523, Test Methodfor Specular Gloss, Vol. 8.01, ASTM, Philadelphia, Pa., 1989. 

Floor poHshes typically are evaluated for gloss, appHcation and leveling properties, discoloration, sHp resistance, scratch resistance, heel-mark resistance, scuff resistance, damp-mopping and detergent resistance, repairabiHty, lack of sediment, and removabiHty (3). RecoatabiHty and formula stabiHty are also important. A review of test methods is available (35). More than 20 ASTM test methods for floor poHshes exist. From the standpoint of product safety, sHp resistance is a particularly important variable and many test methods are available (39). 

In considering exposure tests, whether in the form of laboratory, field or service tests it is important to consider the purpose of the test and the relevance of the data to the anti-corrosion function of the coating. Thus, in the case of paint coatings, factors such as gloss deterioration, chalking and colour retention are of considerable importance in some industries, for example the automotive industry, but perhaps of minor importance in the painting of structural steelwork. These assessment factors can nevertheless be of significance since they may be the precursors of corrosion of the basis metal. 

In this test for transparent plastics, the loss of optical effects is measured when a specimen is exposed to the action of a special abrading wheel. In one type of test the amount of material lost by a specimen is determined when the specimen is exposed to falling abrasive particles or to the action of an abrasive belt. In another test, the loss of gloss due to the dropping of loose abrasive on the specimen is measured. The results produced by the different tests may be of value for research and development work when it is desired to improve a material with respect to one of the test methods. The variables that enter into tests of this type are... 

Figure 2. Light stability of a high-solids, one-coat silver metallic paint based on a two component polyurethane. Test criterion gloss retention QUV irradiation. (HALS) Bis-(2,2,6,6-tetramethyl-piperidinyl-4)sebacate (UVA) 2-(2 -hydroxy-3, 5 -di-tert-amylphenyl) benzotriazole.

This is especially true in industrial and urban areas. Fig. 87 shows a paint containing Chrome Yellow, which was subjected to a test as described in Section 1.6.2.2 treatment with 1 N sulfuric acid for one hour at 70°C. The distinct color change on the circular test area is accompanied by a considerable gloss reduction. In the corresponding lead chromate-free system, it is only the binder that is affected, which reduces the gloss the color value on the other hand is retained. 

BS 2782 Method 520A, Methods of testing plastics. Optical and colour properties, weathering. Determination of specular gloss, 1992. 

Top Coating with Nitrocellulose Lacquer Gloss Impact Resistance Tape Hatch Test ASTM G14-72 ASTM D3002-71... 

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