Airtight adhesive strip DOUBLESHIELD 3.3

coldzincHDPE

Product overview
Metalnastri DoubleShield 3.3 is an anticorrosion tape combining a sacrificial laminated zinc inner layer (>99.95% purity) with an outer self-adhesive polymer-modified bitumen membrane bonded to an HDPE carrier. The system provides combined active (galvanic) and passive (sealing) protection for buried metal structures and is solvent-free, designed for long-term underground service with minimal maintenance.

Description
DoubleShield 3.3 couples an electro-conductive adhesive laminated zinc tape (active protection) with a self-adhesive membrane of polymer-modified bitumen on an HDPE carrier foil (passive sealing). The membrane bonds to the zinc, creating an integrated barrier that seals and protects the sacrificial anode layer.

Features

• Active protection: sacrificial action of high-purity laminated zinc and electro-conductive adhesive that ensures electrical continuity between substrate and zinc for galvanic protection.
• Passive protection: outer polymer-modified bitumen membrane with HDPE carrier provides mechanical sealing, crack-bridging and resistance to moisture and mechanical damage.
• Chemical resistance: outer coat formulation resists aggressive soil constituents commonly encountered underground.

Main uses

• Underground pipelines
• Steel lighting poles
• Underground steel storage tanks
• Transition joints between buried and above-ground steel structures

Active protection
The inner laminated zinc with electro-conductive adhesive establishes positive electrical contact with the metal substrate. When coating defects or electrolyte ingress occur, local galvanic cells form and the zinc behaves as a sacrificial anode, dissolving to protect the steel. The homogeneous zinc lamina reduces local tension variations and exhibits low self-corrosion consumption.

Passive protection
The outer membrane is a self-adhesive, cold-applied polymer-modified bitumen layer with HDPE carrier. It provides immediate resistance to water and soil moisture, tear resistance, cold flexibility and crack-bridging capacity, while preventing contamination of groundwater.

Technical specifications

• Composition: inner laminated zinc layer (>99.95% purity) with electro-conductive adhesive; outer self-adhesive polymer-modified bitumen membrane with HDPE carrier foil
• Protection type: combined active (galvanic sacrificial zinc) and passive (sealing membrane)
• Application: cold-applied, self-adhesive tape/membrane for underground use
• Typical uses: underground pipes, lighting poles, underground storage tanks, transition joints
• Chemical resistance: formulated for resistance to aggressive soil substances
• Environmental: solvent-free; designed not to contaminate groundwater
• Mechanical: flexible, tear-resistant, crack-bridging, cold-bending
• Electrical: electro-conductive adhesive ensures electrical continuity between substrate and zinc