DPF Diamond Dotted Insulation Polyester Film

The diamond dotted insulation film also called Diamond Pattern Film (DPF), is a polyester film base material coated with a resin in a diamond-grid pattern, which is then baked into a semi-cured state. This film is primarily used for inter-layer and inter-turn insulation in SF₆ instrument transformers and power transformers.

Grid Side Length: 9.4 mm

Grid Spacing: 6.5 mm

Why the "Diamond" Pattern?In high-voltage applications like SF₆ transformers, the diamond-grid resin pattern is functional rather than decorative. When the coils are heated during the manufacturing process, the resin melts and bonds the layers together. However, because the resin is not a solid coat, the open spaces (the "spacing") allow for:

1. Air/Gas evacuation: Ensuring no bubbles are trapped.

2. Oil/Gas circulation: Allowing the insulating medium (SF₆ gas or transformer oil) to flow through and cool the components.

Diamond-pattern adhesive polyester film is an insulating material made by applying modified specialty epoxy insulating resin in a diamond pattern onto electrical polyester film and baking it to a partially cured stage. Since the resin coating on diamond-pattern adhesive polyester film is not continuous but dot-shaped, the uncoated channels facilitate the removal of air between insulating layers and the penetration of liquid, thereby minimizing corona damage and partial discharge degradation. It can be used as interlayer insulation in gas or oil insulation systems. It is mainly employed for interlayer and interturn insulation in sulfur hexafluoride (SF₆) instrument transformers and transformers.

Curing Conditions:

The film can be cured under either of the following conditions: At 90°C ± 5°C for 16 hours, or At 110°C ± 5°C for 6 hours.

Storage of Electrical polyester film:

The DPF polyester film should be stored in a dry, ventilated, and clean environment at a temperature not exceeding 25°C. It must be protected from high temperatures and direct sunlight. The storage period is six months. If the storage period is exceeded, the adhesive strength should be tested, and the product may still be used if it meets the required standards.