Double Shield

Monday, June 30th, 2014

 

001

The anticorrosion tape “Double Shield” is a new concept of technology based on a double active-passive protection barrier. The product is a compound between two different layers of material: a sacrificial anode as inner layer and a sealing membrane as outer layer. The result is a unique and effective product that provides active protection to the metal surface that has to be covered with, and a physical-chemical passive protection. “Double Shield” is a free solvent and environmentally friendly. It is designed to protect permanently underground structures, providing protection for the life-span of the same and virtually avoiding any future maintenance.

DESCRIPTION

The product “Double Shield” is a coupling between an electro-conductive adhesive laminar zinc tape with the main purpose of active protection, and a self-adhesive membrane made from a polymer- modified bitumen with a HDPE carrier foil that performs as external sealing, working as a barrier for physical and chemical protection.

FEATURES

Active protection: is provided by the sacrificial action of the high purity laminated zinc (>99.95%) by its electro- conductive adhesive which ensures a positive electric connections between the metal substrate and the zinc so that it can act as a sacrificial galvanic anode.
Passive protection: is given by the top coat bonded to the zinc foil, this is composed of a membrane made from a polymer-modified bitumen with HDPE carrier foil which bonds in an excellent way to the zinc, sealing and protecting it against any external attack and any mechanical damages
Chemical protection: the special composition of the outer coat provides a resistance to all the aggressive substances that naturally occur in soils.

MAIN USES

“Double Shield” is used mainly for:

– underground pipes;

– steel pole for the public lighting;

– underground steel storage tanks;

– joining under-ground and above-ground steel structures

ACTIVE PROTECTION

An anticorrosion protection by means of insulating coating ( paintings, plastics, rubber and so on) achieves exclusively a passive protection of the surface.
Double Shield coating with electro-conductive adhesive, represents an effective step ahead in the technique of protection against spontaneous corrosion phenomena of whichever metal structure.
The Double Shield’s inner layer ensures a positive electrical connection between the metal substrate and the zinc , through the specially formulated electro-conductive adhesive.
The high dissolution tension of zinc tape and its fixing to the steel surface by means of binder in the electro- conductive film permits, whenever in some areas there is a lack of coating or whenever an electrolyte infiltrates between the metal structures and the zinc tape, the immediate formation of a galvanic cell, in which, the zinc becomes an anode dissolving itself and protecting the metal structure (cell cathode). In this case the product realizes an “active protection” of the metal surface.
The complete homogeny and isotropy of the zinc lamina avoid, all along the superficial development, the presence of variations of dissolution tension: it has a very low auto-corrosion consumption.

TECHNICAL DATA OF PASSIVE PROTECTION

Double Shield’s outer layer is a self-adhesive bituminous sealing membrane cold-applied, that is a self- adhesive, flexible, crack-bridging made from polymer-modified bitumen with HDPE carrier foil on one side.
It is used for underground structures permanently against ground moisture (capillary water, retained water) non-accumulating seepage water.

The self-adhesive bituminous sealing membrane with HDPE carrier foil affords immediate resistance to water and driving rain, is flexible, tear-resistant and cold-bending. It is environmentally friendly and is resistant to all aggressive substances that occur in soils. It does not contaminate ground water.

composition weight width
gr/m2 micron
Membrane 1000 1000
Zinc foil 560 80
Adhesive 500 Min.225
Paper 90 75
TOTAL Zinc and Membrane 2150 1380
TOTAL Zinc 700 80
TOTAL Membrane 1590 1290
Property  
Membrane Measuring Unit Value
weight Kg/m2 1.1
weight Membrane mm 1.0
Adhesive thickness 200
Application temperature +3
condition
Rain resistance Immediate
Heat resistance DIN EN 1296 DIN EN 1298 Shape stability
                           70 storage Period 12 Weeks
Cold-bending test DIN EN 1109 No cracks at 5
Water impermeability DIN EN 1928, Procedure B Impermeable
                                                                          Water Pressure 4 bar, 24 h.
Water-Vapour permeability DIN 1931, Procedure B SD= 320m, =2744000
Ultimate tensile Strength DIN EN 12311-2, Procedure A Longitudinal  90//50mm
     Transvers  70//50mm
Extension at ultimate tensile strength DIN EN 12311-2, Procedure A Longitudinal  900%
     Transvers  700%
Tear resistance test EN12310-1 Longitudinal 125 N
                                                                                                                                                     Transvers 65 N
Colour Black
Laminate Zinc Measuring Unit Value
Thickness mm 0,080 (-0,005/+0,020)
Purity % 99,95
Adhesive Measuring Until Value
Thickness mm 0,025
Adhesive on steel
48 h after application N/mm 0,65
Adhesion zinc to membrane N/mm  0,8
Shear resistance Hours  8
Electrical conductivity Ohm.mm2  10
Minimum temperature for application +3
Working temperature -10a +70
Maximum temperature for short period(1/2 hours) +100
Paper Measuring Unit Value
Weight Gr/m2 905%
Thickness mm 775

 


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