Sikaflex®-403 Tank & Silo
Elastic polyurethane sealant for tanks and silos
Sikaflex®-403 Tank & Silo is a 1-part, moisture-curing, elastic polyurethane sealant which is resistant to organic acids as found in liquid manure and silage liquids. The product is used for sealing segmented and bolted tanks, concrete containers, floor joints and sewage systems.
- Resistant to organic acids such as silage liquids.
- Resistant to domestic and municipal sewage, liquid manure and silage liquid.
- Resistant to wastewater such as domestic and municipal sewage and liquid manure.
- Resistant to temperatures of +65 °C as found in thermophilic digestors.
- Very low swelling in organic acids enabling use for floor joints trafficked by front loaders.
- Good mechanical resistance.
- Very good resistance to specific chemicals.
- Very good tear propagation resistance.
- Movement capability of ± 20 % (ISO 9047).
Usage
Sikaflex®-403 Tank & Silo is used for:- Sealing joints that are exposed to organic acids. A typical application is the sealing of joints in segmented and bolted enameled steel or stainless steel tanks including wall-to-floor connection.
- Tanks for the anaerobic digestion process including biogas tanks.
- Tanks for thermophilic and mesophilic digestion for biogas production.
- Liquid manure tanks.
- Drive-in silos for agricultural use.
- Agricultural stables.
- Silage clamp retaining walls.
- Domestic and municipal sewage treatment plants including wastewater.
- Floor joints where very high chemical resistance to organic acids is required.
Advantages
- Resistant to organic acids such as silage liquids.
- Resistant to domestic and municipal sewage, liquid manure and silage liquid.
- Resistant to wastewater such as domestic and municipal sewage and liquid manure.
- Resistant to temperatures of +65 °C as found in thermophilic digestors.
- Very low swelling in organic acids enabling use for floor joints trafficked by front loaders.
- Good mechanical resistance.
- Very good resistance to specific chemicals.
- Very good tear propagation resistance.
- Movement capability of ± 20 % (ISO 9047).
Packaging
600 ml cylindrical foil pack | 20 foil packs per box |
Refer to the current price list for available packaging variations.
Colour
Available in a range of colours. Refer to the current price list for the colour range.
Product Details
APPROVALS / STANDARDS
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Assessment of the joint sealant DIN EN 14188-2:2005-03, Sikaflex-403 Tank & Silo, SKZ, No. 224872/22.
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Foodstuff and migration behaviour EN 1186, EN 13130, CEN/TS 14234, ISEGA, No. 56997 U 22.
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General building regulations, DIBt, No. Z-74.62-212.
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CE marking and declaration of performance based on EN 15651-4:2012 Sealants for non-structural use in joints in buildings and pedestrian walkways — Part 4: Sealants for pedestrian walkways.
Chemical Base
Polyurethane
Shelf Life
12 months from date of production
Storage Conditions
The Product must be stored in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +5 °C and +25 °C. Always refer to the packaging.
Refer to the current Safety Data Sheet for information on safe handling and storage.
Density
1.20 kg/l | (ISO 1183-1) |
Shore A Hardness
40 (after 28 days) | (EN ISO 868) |
Secant Tensile Modulus
0.90 N/mm2 at 60 % elongation (+23 °C) | (ISO 8339) |
Movement Capability
± 20 % | (EN ISO 9047) |
Elastic Recovery
80 % | (EN ISO 7389) |
Tear Propagation Resistance
10.0 N/mm | (ISO 34-2) |
Service Temperature
IMPORTANT
Depolymerisation due to exceeded service temperature
In any process system, service temperatures affect the aggressiveness of the chemical mixture. Exceeding the stated performance limits could cause depolymerisation of the sealant.
- During specification, analyze the content of the chemicals to establish their behavior at temperature, and to define the continuous maximum service temperature.
Service temperature range in a dry condition.
Maximum | +80 °C |
Minimum | -40 °C |
Maximum service temperature in a wet condition.
Movement joints | ≤ +45 °C |
Overlap sealing | ≤ +65 °C |
Chemical Resistance
IMPORTANT
Depolymerisation due to chemical attack
The Product is not fully chemically resistant until the product has fully cured. Moreover, chemical resistance depends on the chemicals, their concentration and their temperature. Exceeding the stated performance limits could cause depolymerisation of the sealant.
- Analyze the content, exposure time and temperature of the chemicals.
- Design the joints for the intended and foreseeable conditions.
Sikaflex®-403 Tank & Silo is resistant to:
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Water
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Sea water
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Liquid manure
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Silage liquid
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Dilute alkali
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Neutral water-based dispersed detergents or cleaners
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Domestic and municipal sewage
Sikaflex®-403 Tank & Silo is not resistant to:
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Concentrated organic and inorganic acids
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Organic solvents
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Chlorinated or aromatic hydrocarbons
Joint Design
Refer to all relevant local construction guidelines and regulations. The sealant must be specified and included in the design of the containment system.
Reference must be made to the following document: Design guideline: Dimensioning of construction joints
Application
Sag Flow
0 mm (20 mm profile, +50 °C) | (EN ISO 7390) |
Product Temperature
Maximum | +40 °C |
Minimum | +5 °C |
Ambient Air Temperature
Maximum | +40 °C |
Minimum | +5 °C |
Substrate Temperature
Maximum | +40 °C |
Minimum | +5 °C |
Beware of condensation. Substrate temperature during application must be at least +3 °C above dew point.
Backing Material
Use closed cell, polyethylene foam backing rod
Curing Rate
At +23 °C and 50 % r.h. | 3 mm per 24 hours |
Skin Time
At +23 °C and 50 % r.h. | 5 hours |
SUBSTRATE PREPARATION
Poor adhesion due to inadequate surface preparation
Note: Primers are adhesion promoters. Primers cannot replace proper surface preparation and surface cleaning.
- Do not use primers for improving poorly prepared or poorly cleaned joint surfaces.
The substrate must be sound, clean, dry and free of all contaminants such as dirt, oil, grease, cement laitance, old sealants and poorly bonded coatings which could affect adhesion of the sealant.
The substrate must be of sufficient strength to cope with the stresses induced by the sealant during movement.
- Use techniques such as wire brushing, grinding, grit blasting or other suitable mechanical tools to remove all weak substrate material.
- Repair all damaged joint edges with suitable Sika repair products.
- Completely remove all dust, loose and friable material from all surfaces before application of any activators, primers or sealant.
- Where joints in the substrate are saw-cut, flush away all slurry material and allow joint surfaces to dry.
The following priming and pretreatment procedures must be followed to ensure optimum adhesion and joint durability for critical, high-performance applications such as joints with chemical load and permanent immersion. Consult the tank manufacturer for information on preparation and priming.
NON-POROUS SUBSTRATES
Enamelled steel
- Pretreat the surface with Sika® Aktivator-205 applied with a clean cloth.
Aluminum, anodised aluminum, stainless steel, galvanised steel, epoxy and fusion-bonded epoxy, powder-coated metals, or glazed tiles.
- Pretreat the surface with Sika® Aktivator-205 applied with a clean cloth.
- Alternatively, prime the surface with Sika® Primer-3 N applied with a brush.
Other metals, such as copper, brass and titanium zinc.
- Pretreat the surface with Sika® Aktivator-205 applied with a clean cloth.
- Wait until the flash-off time is over.
- Prime the surface with Sika® Primer-3 N or Sika® Primer-115 applied with a brush.
PVC substrates
- Prime the surface with Sika® Primer-215 applied with a brush.
POROUS SUBSTRATES
Concrete, aerated concrete and cement-based renders, mortars and bricks
- Prime the surface with Sika® Primer-3 N or Sika® Primer-115 applied with a brush.
For more details of the primer or pretreatment products, refer to the corresponding Product Data Sheet. Contact Sika Technical Services for additional information.
APPLICATION
IMPORTANT
Strictly follow installation procedures
Strictly follow installation procedures as defined in Method Statements, application manuals and working instructions which must always be adjusted to the actual site conditions.
IMPORTANT
Application by trained personnel
The application of this product must only be carried out by an applicator that is trained or approved by Sika. The applicator must also be experienced in this type of application.
IMPORTANT
Allowing insufficient curing time
Putting the product into service too early can result in a reduction of the long-term stability of sealed sections.
- Allow the product to fully cure before it is exposed to mechanical or chemical stress.
IMPORTANT
Damage due to corrosion
Corrosion protection is dependent on the thickness of the sealant layer. For butt or lap joints the product provides effective protection at an application thickness of ≥ 8 mm.
IMPORTANT
Resistance to chlorine
The product is resistant to chlorine for tank disinfection and dosing purposes only.
- Contact the tank supplier for guidelines and detailed conditions on dosing and disinfection.
IMPORTANT
Degradation of sealant due to substrates leaching oil, plasticisers, or solvents
Bitumen, natural rubber or EPDM rubber can leach oils, plasticisers, or solvents that can degrade the sealant and cause the product to become tacky.
- Do not use the product on building materials which leach oils, plasticisers, or solvents.
IMPORTANT
Staining on natural stone substrates due to plasticiser migration
Staining from plasticiser migration may occur when used on cast, reconstituted or natural stone such as granite, marble or limestone substrates.
- Do not use on natural stone substrates
IMPORTANT
Degradation of sealant due to chemical attack
- Do not use the product to seal joints in and around swimming pools containing water treatment agents such as chlorine.
IMPORTANT
Insufficient curing due to exposure to alcohol
Exposure to alcohol during curing may interfere with the curing reaction and cause the product to remain soft or become tacky.
- Do not expose the product to alcohol-containing products during the curing period.
- Apply masking tape where neat or exact joint lines are required.
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After the required substrate preparation, insert a backing rod to the required depth.
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Prime the joint surfaces as recommended in substrate preparation.
Note: Avoid excessive application of the primer. - Open the seal on the top of the cartridge or open the end of the foil pack.
- Fit the nozzle and cut it to the desired bead size.
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Insert the product into the application gun.
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Apply the product into the joint.
Note: Avoid air entrapment. Make sure that the product comes into full contact with the adhesion area of the joint. - IMPORTANT Do not use tooling products containing solvents. As soon as possible after application, tool the product firmly against the joint sides to ensure adequate adhesion and a smooth finish. Use a compatible tooling agent such as Sika® Tooling Agent N to smooth the joint surface.
- Remove the masking tape within the skin formation time of the product.
For lap joints such as in enameled steel containers consult the tank manufacturer for specific application advice.
OVERPAINTING THE SEALANT
IMPORTANT
Tacky paint due to plasticiser migration
Paints and sealants or adhesives may contain plasticizers and other substances that migrate and can cause the painted surface to become tacky.
IMPORTANT
Cracking paint due to joint movement
Rigid paint applied on top of a sealant or flexible adhesive may crack when used on joints subject to movement.
The product can be overpainted with most conventional paint coating systems.
- Allow the product to fully cure before overpainting.
- Before overpainting, carry out preliminary trials to test compatibility of the paint or coating system with the product in accordance with ISO/TR 20436:2017 – Buildings and civil engineering works — Sealants — Paintability and paint compatibility of sealants.
Colour variation
Note: Colour variation may occur especially with white or other light colour shades. This effect is purely aesthetic and does not adversely influence the technical performance or durability of the product.
CLEANING OF TOOLS
Clean all tools and application equipment immediately after use with Sika® Thinner C. Once cured, hardened material can only be removed mechanically. For cleaning skin use Sika® Cleaning Wipes-100.