ZnS based phosphorescent Pigment -GSS Series

Application methods

Application methods

For paints:

A phosphorescent paint is a mixture of phosphorescent pigment and a special binding medium. Binding mediums to be used are of high transparency and be selected according to the material to be painted and the method of painting (By brush, spray injection, machine coating, etc.). Binding mediums with an ability to enhance the light stability characteristic are desirable.

  • The standard ratio of mixing is 1:1 by weight. A higher content of the pigment in the mixture increases the brightness.
  • The higher the transparency of the binding medium, the higher level of brightness obtained.
  • Binding mediums and dilutors used with phosphorescent pigment should be free from heavy metal substances. Heavy metal elements, by chemical reactions with the pigment, may affect the properties of the pigment.
  • The standard thickness of phosphorescent paint is 100< . The brightness increases with thickening the painted layer, however, the brightness saturates at a thickness of 300< .
  • A mixture of 1g of phosphorescent pigment and 1g of a binding medium is good for painting an area of 10 x 300 mm (0.1 mm thick).
  • White background always offers a more effective brightness, i.e., assuming the percentage of decrease in brightness for white is 0%, silver will be 10 - 25%, green 30 - 35%, and black 45 - 50%. The color of the substrate will also effect the body color of the phosphorescent paint.
  • Over-coating with a transparent varnish after painting enhances the light stability and increases the life of the phosphorescent paint. For selection of over-coating varnish, use the aforementioned criteria.

For inks:

Phosphorescent inks are made by mixing phosphorescent pigment and a special binding medium. Only silk-screen printing is available for phosphorescent printing. Give a good care in the selection of binding mediums.

  • A most common printing screen is of 150 mesh and 150< thick. After drying, the thickness of phosphorescent layer will become about 80< and fine-line printing and a smooth surface will be obtained. Other specifications are the same with paint.

For plastic resins:

Phosphorescent pigment can be incorporated in to most of the synthetic resins, but the resins must be transparent. Most of the molding processes commonly used are applicable. As the specific gravity and the particle size of the pigment are 4.1 and 15 - 25< respectively, the pigment should be in a pellet or granule form before processing.

  • The mixing ratio of phosphorescent pigment to a resin is 10 - 20%. The more the pigment is mixed, the higher the brightness becomes. (Fig.7)
  • Because the main composition of phosphorescent pigment is phosphorous zinc sulfide (ZnS:Cu), resins and additives that contain heavy metals, i.e. lead, iron, cadmium, should be avoided.
  • As the phosphorescent pigments are made through calcination process at about 1,300°C, they stand relatively high temperatures. But in a resin that contains some heavy metals, heat from the mold could act as an accelerator for change in quality. Higher acid content will also affect the pigment in use for a long period.
  • No coloring agents should be mixed to the resin. They could affect the phosphorescent property of the pigments. Refer to phosphorescent paint for other specifications for thickness, substrate, color, etc.

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