April 2015 Archives

Evaluation using the rating number is employed as an evaluation method for the results of corrosion resistance tests such as salt spray tests.

(1) Checking test piece

On the test piece after the corrosion resistance test, corrosions in the form of pit, stain from corrosions in the base material, scale-like peels, lumpy corrosions, dendritical corrosions, swollenness, cracks on the plating film, etc. are observed.The test is to check if these corrosion products are properly removed.

(2) Surfaces subjected to evaluation

As shown in [Fig. 1], the surface with the specified sections removed from the test piece edge is subjected to the test.

(3) Evaluation using rating number standard drawings

Evaluate the degree of corrosion by visually checking the surface against the rating number standard drawings as shown in [Fig. 2].

(4) Evaluation by actual measurement of corroded area

If the shapes of corrosion are too complex to check it against the standard drawings, actually measure the corrosion areas to determine the rating number in the following manner:

1. Use a magnifying lens with magnification power of 10 times or more to look for the corrosion section larger than 0.1mm in shorter diameter and measure the longer diameter (d1) and shorter diameter (d2). Then calculate the corroded area by the formula: (d1 x d2 x π)/4
2. Divide the total of corroded area calculated in step 1 by the area of the surface subjected to evaluation to determine the ratio of all corrosion area.
3. Determine the rating number from the ratio of all corrosion area using [Table].

Slippery surfaces on roads, floors in the factory, or pathways may cause traffic accidents or industrial accidents.As dust or fine particles are accumulated on a floor, attracted by static electricity arising on the surface, the floor may become slippery. A watery floor on the poolside likewise may become slippery.
Anti-slip paints containing chlorinated rubber, chrome oxide, baryte, or sand are often used for poolside. For steel base materials, primer paints are required as foundation coating before applying the anti-slip paint.
Abrasions or degradations on the pathways, roads, etc. may cause skidding accidents involving people and cars, and water or oil on the smooth surface will make the floor slippery.To prevent such accidents, slip resistance is required to secure safety for people and vehicles.The performance of slip resistance is represented by a slip-resistance coefficient. A slip-resistance coefficient of 0.4 (preferably 0.45) or greater is generally required.

Properties necessary for the anti-slip paint include a seamless finished surface, abrasion resistance, impact resistance, high slip-resistance coefficient, partial maintainability, long durability of slip resistance, adhesion, alkali resistance, etc.

Resin-type anti-slip paint is available in two types: one-component type and two-component type.One-component type is composed of acrylic resin, vinyl resin, rubber-base synthetic resin, color pigments, body pigments, and anti-slip materials.Two-component type is composed of epoxy resin, urethane resin, color pigments, body pigments, curing agent, etc.For coloring, black, green, and brown are often used. For anti-slip materials, silica sand, artificial silica sand, rubber powder, plastic chips, etc. are used.Bone materials are often sprayed on the coating surface before curing in order to form a rough surface.

Appearance is also an important element for anti-slip paints.Colorfulness is required for leisure facilities and public facilities. Specific colors are necessary for outdoor tennis courts, for example.
Acrylic emulsion dispersed with the coarse powder of aluminosilicate or calcium carbonate is often used for outdoor tennis courts.For the dark green top coat, acrylic emulsion paint dispersed with aluminosilicate, silica, green chrome oxide, and black ferric oxide, mixed with vinyl acetate and acrylic emulsion dispersed with asbestos is used. This exhibits excellent properties at lower temperatures.

Guide markings on a road surface, such as zebra zones, require sufficient safety to prevent slipping on the marking.Properties necessary for guide markings on a road surface are night visibility, slip resistance, durability, safety in construction, good water drainage, no hindrance during snowplowing.