PU foam strip Ø 20mm (open cell)

Open-cell joint round profile Ø 20mm made of PU

For all joints ✓ For indoor & outdoor ✓ Flexible design ✓

Our open-cell round profiles made of polyurethane with a diameter of 20mm are available in metre lengths at favourable prices. We offer attractive discounts for larger purchase quantities. The foam strips, made of grey PU foam, are soft and flexible and can be used for all types of joints indoors as well as for joints outdoors. The 20 mm round profiles are suitable for joints with a width of approx. 12 mm-15 mm. In addition, the joint depth should be at least 30mm in order to achieve a sufficiently high thickness of the sealant.

The joint cord is suitable as a filler material for expansion joints and wall connection joints in both interior and exterior areas and is, thus, ideal as a joint delimiter for windows and doors that are subsequently to be sealed with silicone, acrylic or an MS polymer. By limiting the joint depth, on the one hand it prevents too much sealant from being applied to the joint, which reduces the costs of silicone consumption. On the other hand, it can be used to regulate the perfect joint depth required for elastic joint sealing. In addition, a round profile prevents the joint from being completely filled with silicone, which creates a three-flank adhesion that has a negative effect on sound insulation or the elasticity of the joint.

Scope of delivery:
• 1 x foam strip Ø 20mm open cell 1000mm length

TIP: The shortening of the 20mm joint cord can be done with household scissors or a cutter knife.

Properties of our PU foam strip in 20mm

Our foam strips made of polyurethane foam are well resistant to chemicals with the exception of petrol or concentrated acids and alkalis. They can be used without hesitation with almost all materials commonly used in the construction sector. PU foam has very good elasticity values with a relatively high tensile strength, so that the resistant round profiles are very easy to work with. In addition to the essential property that round profiles are used to limit the depth of expansion joints or construction joints, the open-cell foam material is also characterised by excellent sound and heat insulating properties, which can contribute to optimising heat loss, especially when sealing window profiles to masonry.

Our foam strips made of polyurethane foam are CFC- and HCFC-free and are considered physiologically neutral. For this reason, the filling cords can also be used indoors without hesitation. For example, to fill joints in wall tiles and floor coverings before they are sealed. The flexible joint cords can also be used perfectly for door frames of interior doors. As a UV-resistant, waterproof sealing material, the open-cell PU is also extremely suitable for all joints in outdoor areas. The only exception are joints that have to withstand sustained high mechanical pressure loads, because the soft, flexible material made of PU foam does not have the necessary inherent strength for such areas of application, so that the joint could tear or give way under certain circumstances due to the mechanical pressure. Possible examples could be the sealing of pressurised booths in paint shops or clean rooms. Joints in tiled swimming pool installations are also subject to high water pressure, so that the open-cell round profile should not be used here.

Technical data of the PU foam strip in 20mm

• Material: Polyurethane
• Colour: Grey
• Diameter: 20mm
• Recommended joint width: 12mm-15mm
• Recommended joint depth: min. 30mm
• Density: 0.125g/cm³
• Shore hardness: 20-40
• Shrinkage hardness: min. 150 KPa according to DIN 53571
• Elongation at break: min. 150% according to DIN 53571
• Compression set: 25%-35% in accordance with DIN 53572
• Temperature resistance: -30°C - +60°C
• Ageing resistance: Excellent
• UV resistance: Sufficient
• Water resistance: Sufficient
• Chemical resistance: Sufficient

NOTE: The round profiles have medium resistance to petrol, concentrated acids and alkalis.

Processing of our 20mm PU joint cord

A round profile is used when the joint is too deep or there is a risk of three-sided adhesion. The round profile is placed in the joint before the sealant is applied, so that it acts as a boundary for the sealant. This can be done quite simply by pressing it in lightly with a finger. However, it is more even and easier to do this with a joint cord roller. The filler material, made of soft, open-cell PU foam, is very easy to press together or to lay around corners and radii. The width and depth of the joint is important when choosing the right joint cord, because the foam strip should have a firm, secure hold so that it does not slip backwards when the sealant is applied. The ideal joint width for the 20mm diameter foam strip is between 12mm and 15mm, while the joint depth should not be less than 30mm to achieve a sufficient thickness of sealant.

With an elongation at break of more than 150%, round profiles made of PU foam have a very high stretchability. However, when working with the joint cord, it should not be stretched too much, because it will contract again over time. This may result in gaps in the backfill and can have a negative effect on the thermal insulation. This is especially true if the round profile is used for wall connection joints of windows and doors.

Application examples:
• Round profiles limit the joint depth and thus ensure the elasticity of the sealant
• To ensure a two-flank adhesion of the silicone, joint cords are excellently suited
• Foam strips made of PU foam are suitable for all sealants such as silicone, MS polymer or acrylic
• Our PU round profiles have very good insulating properties for joints on window profiles
• Round profiles are ideal for use as joint filling material for expansion joints and construction joints

The temperature resistance of our round profile ranges from -30°C to +60°C. The processing temperature, on the other hand, should be between +5°C and +40°C and is thus comparable to the temperature range at which sealants such as silicone, acrylic or MS polymers can be processed. Furthermore, it should be ensured that the foam strips are stored and processed in a dry place and that no moisture is absorbed during processing (e.g. by rain), because after sealing with the selected sealant the absorbed moisture may no longer be able to escape quickly enough.

NOTE: Before processing, the round profiles should be stored in a dry place. The perfect storage temperature is between +5°C and +25°C.