3M SJ3550CF Dual Lock Reclosable Fastener 25 mm x 45.7 m

What Is 3M™ Dual Lock™ SJ3550CF?

3M™ Dual Lock™ SJ3550CF is a reclosable mechanical fastening system that offers excellent holding strength and can be opened and reclosed as often as needed (up to 1,000 cycles).

Unlike traditional hook-and-loop fasteners, it uses mushroom-shaped stems that interlock with one another.

The SJ3550CF consists of a black polyolefin backing with a stem density of 250 (250 stems per square inch) and a clear, pressure-sensitive acrylic adhesive. Thanks to this adhesive layer, the fastening strip can be applied to suitable surfaces without the need for drilling holes or using traditional screws and bolts.

This version is supplied in rolls 25 mm wide and 45.7 m long. It is ideal for industrial assemblies, removable panels, equipment covers, and other applications that require a robust, reclosable fastening system.

How Does the 3M Dual Lock Reclosable Fastening System Work?

The fastening system consists of two compatible strips with mushroom-shaped stems. When the strips are pressed together, the stems interlock to create a secure mechanical connection. Pulling the strips apart disengages the connection and allows the components to be separated.

The fastening strength depends on the combination of stem densities, the engaged area, the substrates and the forces acting on the assembly.

3M™ Dual Lock™ SJ3550CF is a Type 250 product and can engage with compatible Type 170 (for a strong hold) Type 250 (for an even stronger hold) or Type 400 Dual Lock fasteners, (for maximum strength) subject to the application requirements.

The connection provides an audible snap when properly engaged, helping the user check that the fastening surfaces have connected.

Key Industrial Advantages of 3M SJ3550CF

• Reusable fastening: Allows for opening and reattaching the components.
• Strong mechanical engagement: Interlocking mushroom-shaped stems create a secure connection when correctly matched and engaged.
• Adhesive-backed installation: The acrylic pressure-sensitive adhesive attaches the fastener to suitable surfaces without conventional mechanical fixings.
• Clean, concealed appearance: Provides an alternative to visible screws, bolts and clips in suitable designs.
• Versatile material compatibility: Suitable for use on metals, glass, painted surfaces, and certain types of plastic (acrylic, PC, ABS).
• Industrial roll format: The 25 mm x 45.7 m roll format supports applications requiring longer strips or multiple fastening points.

Which Materials Can 3M Dual Lock SJ3550CF Be Used On?

The acrylic adhesive is designed to bond to a range of medium- and high-surface-energy materials. Compatibility should be confirmed for the exact substrate, finish and operating conditions.

• Metals: such as aluminum or stainless steel
• Glass: the surface must be thoroughly cleaned before application
• Plastics: those with high surface energy, such as acrylic, PC, and ABS.

Powder-coated surfaces or surfaces with low surface energy (PP, PE) may require a different fastening solution, the use of a primer, and, in any case, appropriate testing.

Typical Industrial Applications

The product is suitable for sectors including furniture, construction, electronics, automotive, transport and special vehicles, as well as general industry.

Fastening of wall and ceiling panels

For instance, in the transport sector, where they simplify maintenance by allowing for easy removal.

Automotive and transport interiors

Suitable applications include linings, panels, and interior components—for example, in vehicle seating, curtains, or the attachment of sound-insulating panels.

Fastening of graphics, signage, and trade show booth components

In the communications industry, where elements may need to be changed with ease.

Fastening of internal panels

Such as walls, doors, and linings—for example, within electronic, industrial, and electrical equipment.

How to Apply 3M Dual Lock SJ3550CF

1. Prepare the surfaces: Remove dust, oil, grease and other contaminants using a cleaning method compatible with the substrate.
2. Check compatibility: Confirm that the adhesive is suitable for both surfaces and that the application conditions are within the product's specifications.
3. Cut the required length: Cut the roll to suit the design and fastening area.
4. Apply the adhesive-backed strip: Remove the release liner and position the strip carefully.
5. Allow the adhesive to develop bond strength: Follow the technical data sheet for the recommended dwell time before loading the assembly.
6. Engage the fastener: Align the compatible strips and press them together until the stems engage.
7. Test the assembly: Check the connection under representative operating conditions before putting the assembly into service.

3M Dual Lock SJ3550CF: Technical Specifications

Frequently Asked Questions About 3M Dual Lock SJ3550CF

Is 3M Dual Lock SJ3550CF reusable?

Yes. Its interlocking stems can be disengaged and re-engaged. 3M lists a typical closure life of up to 1,000 cycles, although actual service life depends on the application, handling and environmental conditions.

What is the difference between Dual Lock and hook-and-loop tape?

Conventional hook-and-loop fasteners use hooks engaging with loops. Dual Lock uses mushroom-shaped stems that interlock with compatible stems, creating a different type of mechanical connection.

Can SJ3550CF replace screws or bolts?

It can be an alternative to screws, bolts or clips in suitable applications where a removable connection is required. Suitability depends on the load, joint design, substrate, environment and safety requirements. It should not replace a safety-critical mechanical fixing without engineering validation.

Which Dual Lock types can SJ3550CF connect to?

SJ3550CF is Type 250 and can mate with compatible Type 170, Type 250 or Type 400 Dual Lock fasteners. The selected combination affects the engagement force and overall fastening performance.

Does the adhesive bond to plastic?

It can bond to selected plastics, including ABS, polycarbonate and acrylic, as well as suitable metals and glass. Adhesion varies with the exact plastic grade, surface finish and preparation, so testing is recommended before use.

Can 3M Dual Lock SJ3550CF be used outdoors?

The product is intended for indoor and outdoor applications, but suitability depends on exposure to temperature, moisture, UV, chemicals and other environmental conditions. Verify the operating limits and test the complete assembly for the intended service environment.