Description

Technical Parameters

Adhesive dispensed polyester insulation film features diamond-lattice epoxy microdots coated on PET film substrate. Compared with paper-based dotted paper, PET substrate offers three key merits: 1. Zero moisture absorption for stable insulation under high humidity; 2. High mechanical strength against tearing; 3. Ultra-smooth surface without fiber burrs that scratch thin copper foil.

A foil-wound dry transformer manufacturer used paper dotted paper previously, whose fiber burrs occasionally damaged their 0.2mm thin copper foil and generated defective products. After switching to our dotted PET film, 100 test samples showed zero copper scratches and full production line conversion. Coating on PET is technically harder than paper due to low surface tension causing resin dot sliding and flowing. Our modified epoxy resin increases thixotropy to maintain uniform, non-flowing dots free of linking or missing spots. Test results: peel strength ≥4N/cm after curing at 180℃, resin dot height 50±10μm, ~60 dots per square centimeter, substrate breakdown ≥8kV and post-dotting breakdown ≥6kV. For distributors, this high-end foil transformer solution has lower price sensitivity and strong client stickiness once validated.

Specification Parameters

Parameter Item	Technical Index
Substrate Thickness	0.05～0.25mm
Maximum Width	1600mm
Resin Dot Height	30～80μm
Temperature Resistance Class	Class F (155℃)
Peel Strength After Curing	≥4N/cm
Breakdown Voltage	≥6kV

Application Fields

Interlayer bonding of foil-wound dry transformers
Fixation and insulation of motor windings
Interlayer adhesion of reactor coils
Scratch-free insulation bonding for thin copper foil
All dot bonding scenarios requiring high-strength substrates

Quality Control

QC focuses on dot precision and adhesion. Microscopic dot diameter, height and spacing inspections every 30 minutes during coating to eliminate linking, missing or flowing dots. Peel strength testing after curing for every batch. Raw PET film undergoes pre-testing for thickness, breakdown and surface energy; low surface energy stock rejected. High-temperature aging tests verify adhesion retention at elevated temperatures. ISO9001 certified with traceable batch records.

Customization Capabilities

Flexible customization. Substrate thickness 0.05~0.25mm matched to insulation requirements. Resin dot height adjustable 30~80μm: taller dots for stronger adhesion, shorter for thinner insulation. Two curing speed options: fast cure (5 mins at 150℃) for high-speed lines, slow cure (30 mins operation window) for complex manual processes. Width range 100mm~1600mm. Full OEM packaging and labeling support. MOQ 500kg, free sample testing.

FAQ

Q: How to choose between dotted PET and dotted paper?

A: Choose PET if you need moisture resistance, smooth surface and copper foil scratch prevention. Choose paper for lower cost and compatibility with traditional oil transformer processes. Dotted PET is the priority for foil-wound dry transformers.

Q: Will resin dots stick at room temperature?

A: No, resin dots remain solid B-stage non-tacky at ambient temperature for easy cutting and stacking; only melt and bond under heat and pressure.

Q: Double-sided dot coating available?

A: Single-sided coating is standard; double-sided coating can be customized based on your bonding structure requirements.

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