will silicone sealant stick to delrin



Silicone sealants are widely used for various sealing applications due to their excellent adhesive properties. However, when it comes to bonding with specific materials like Delrin, also known as polyoxymethylene, the question arises - can silicone sealants effectively stick to Delrin? In this article, we will delve into the properties of silicone sealants and Delrin, explore their compatibility, understand the factors that may affect their bonding strength, and provide some tips for achieving a successful bond. So, let's get started.

Understanding Silicone Sealants and Delrin

Silicone Sealants:

Silicone sealants are a popular choice for sealing and bonding applications due to their flexibility, durability, and excellent resistance to temperature extremes, chemicals, and UV radiation. These sealants are typically based on silicone polymers and are available in various formulations such as one-component, two-component, acetoxy cure, or neutral cure. Silicone sealants are commonly used in construction, automotive, electronics, and various other industries.


Delrin, or polyoxymethylene (POM), is a thermoplastic polymer known for its excellent mechanical properties, such as high stiffness, dimensional stability, and low friction coefficient. It is widely used in precision parts, gears, bushings, and other applications where mechanical strength and wear resistance are crucial. Delrin is chemically resistant to many solvents and chemicals, making it suitable for diverse industrial applications.

Compatibility Between Silicone Sealants and Delrin

The compatibility between silicone sealants and Delrin depends on various factors, including the formulation of the sealant and the surface characteristics of Delrin. In general, silicone sealants have good adhesion to many materials, including plastics, but the adhesion can vary depending on the specific polymers used.

Factors Affecting Bonding Strength

1. Surface Preparation:

Proper surface preparation is crucial for achieving a strong bond between silicone sealants and Delrin. The surface should be thoroughly cleaned to remove any dirt, dust, grease, or other contaminants. Cleaning can be done using solvents like isopropyl alcohol or other suitable cleaning agents. Additionally, roughening the surface by sanding or using adhesion promoters may enhance the bonding strength.

2. Curability:

The curing mechanism of silicone sealants can affect their compatibility with Delrin. Acetoxy cure silicone sealants release acetic acid during the curing process, which might lead to an acidic environment. In such cases, Delrin's surface may degrade, compromising the bond strength. Neutral cure silicone sealants, on the other hand, are less likely to cause such issues.

3. Compatibility Testing:

Conducting compatibility tests is essential to ensure that the silicone sealant is suitable for bonding with Delrin. Applying a small amount of sealant on a test area and allowing it to cure can help assess the bond strength and performance over time. Compatibility testing also helps detect any adverse reactions between the sealant and Delrin which may affect durability.

Tips for Successful Bonding

1. Choose the Right Silicone Sealant:

Selecting a silicone sealant with excellent adhesion properties to plastic materials is crucial. Look for sealants specifically designed for plastic bonding or those that mention compatibility with Delrin or similar materials.

2. Pre-test the Bond:

Always perform a compatibility test on a small, inconspicuous area before applying silicone sealant to the entire surface. This ensures that the sealant adheres properly and does not cause any adverse reactions.

3. Surface Preparation:

Thoroughly clean the Delrin surface using appropriate solvents or cleaning agents to remove any contaminants. Roughening the surface with sandpaper can enhance the bonding strength. Use adhesion promoters if necessary.

4. Proper Application:

Follow the manufacturer's instructions for applying the silicone sealant. Apply the sealant evenly and ensure it covers the entire bonding area. Use masking tape or other methods to contain the sealant within the desired area.

5. Curing Time:

Allow the silicone sealant sufficient time to cure before subjecting it to stress or environmental factors. Proper curing provides optimal bonding strength and durability.


In conclusion, while silicone sealants generally have good adhesion to plastics, including Delrin, proper surface preparation, and selection of the right sealant are crucial for achieving a strong and durable bond. By following the tips mentioned above and conducting compatibility tests, you can ensure successful bonding between silicone sealants and Delrin, enabling you to create secure and long-lasting seals in various applications.


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