One-part Polyurethane Low Modulus Construction Sealant Certified According to EN 15651/1; EN 15651/4; ASTM C920 LEED Compliant
U-Seal 907 is a one-component, gun-grade, non-sag polyurethane low modulus construction sealant.
It cures under the influence of atmospheric moisture to form a permanently elastic sealant with
excellent adhesive properties and resistance to ageing and weathering.
- Permanently elastic over a wide range of temperatures; accommodates joint movement of ±50%
- Non-sag consistency with short cut-off string
- Non-sticky / does not pick up dirt
- Easy to gun with excellent tooling consistency
- Good adhesion on all typical construction materials.
- Non-staining on concrete and porous materials
- Good resistance to ageing, weathering and immersion in cleansing agents, sea water, lime water and dilute caustic solutions
- Over-paintable with many water and solvent based paints (preliminary tests recommended)
Areas of Application
- Sealing expansion and construction joints in vertical and horizontal applications
- Joints in precast elements
- External walling and cladding joints.
- Weatherproofing of joints between brickwork, block-work, masonry, wood, concrete, metal frames.
- Joints in walls, floors, balconies, around window or door frames
- Joints in water channels and suitable for hydraulic general sealing with contact with water.
- Bridge and balcony parapets.
- Retaining walls
- Metal roof and gutter sealing
Surfaces must be clean, dry, free of water, oil, grease or rust and of sound quality. Remove all loose particles or residues with a jet of compressed air, sandpaper or hard brush. Glass, metal and other non-porous surfaces must be free of any coatings and wiped clean with solvent. Pre-cast panels using form-release agents other than polyethylene film must be sandblasted or mechanically abraded and dust free.
U-SEAL 907 has very good adhesion properties without the use of primer on most common building materials. Consequently, the use of the primer is not necessary if the support to be sealed is properly prepared and consolidated. However, varieties of brick, natural stone, plastics, paints, coatings and other treatments of surfaces often presents a difficult surface to which to adhere. Due to the number of unpredictable atures of these substrates, a preliminary test is recommended. If necessary, apply a coating of primer on the joint walls (U-Primer 110 for porous surfaces).
Recommended application temperatures: 15°-25°C. For easier use or cold weather application we recommend the material to be stored at approximately 25°C prior to use. In order to guarantee free movement of sealant in joints, it is imperative that the sealant does not adhere to the bottom of the joint, herefore for correct joint making a closed-cell polyethylene bead (joint backing rod) is to be placed at the proper depth.
If necessary, apply appropriate primer to joint sides and observe waiting time to avoid that trapped solvent, in condition of rising temperature, can blow bubbles in the uncured sealant. For best performance, sealant should be gunned into joint when the joint slot is at mid-point of its designed expansion and contraction. Firmly extrude sealant into the joint making sure that it is in full contact with the sides of the joint and with the backing rod at the bottom. Keep the nozzle in the sealant, continue on with a steady flow of sealant preceding the nozzle to avoid air entrapment. Avoid overlapping of sealant to eliminate entrapment of air.
For the successful sealing of joints it is essential that the following guidelines on joint configuration are observed:
For joints up to 12 mm wide, width to depth ratio = 1 : 1
For joints over 12 mm wide, width to depth ratio = 2 : 1
Finishing indications and limitations
Sealant should be tooled to a smooth finish ensuring a full contact to the sides and back up material into the joint, this will also contribute in breaking the air bubbles which may be formed inside the sealant. Masking tape should be used where sharp exact joint lines or exceptionally neat lines are required. Remove the tape whilst the sealant is still soft.
Alu- cartridge 310 mL 12 cartiridges per box
Alu-PE bags 600 mL 20 bags per box
U-Seal 907 can be stored for 12 months in its original packaging (unopened container) at 10°- 25°C in a cool, dry place. The storage temperature should not exceed 25°C for extended periods of time. Keep away from wet areas, direct sunlight and heat sources.