What to do if the peel force of pressure-sensitive adhesive increases?

To improve the peel strength climbing effect of pressure-sensitive adhesives, comprehensive measures can be taken, such as adjusting the crosslinking structure, optimizing the molecular weight distribution, introducing polar monomers, controlling the adhesive layer thickness, and selecting suitable substrates.

The following is a detailed analysis:

1. Adjusting the Crosslinking Structure

Crosslinking Agent Selection: Using polymers as crosslinking agents increases the number of crosslinking points, making the crosslinking structure of the pressure-sensitive adhesive more compact, thereby improving peel strength. For example, chemical crosslinking agents or radiation crosslinking (such as ultraviolet light, electron beam) can optimize the crosslinking structure and enhance cohesive strength.

Crosslinking Degree Control: Moderate crosslinking can balance cohesive strength and interfacial adhesion. Insufficient crosslinking may lead to cohesive failure, while excessive crosslinking may reduce wettability. The optimal amount of crosslinking agent needs to be determined experimentally.

2. Optimizing Molecular Weight and Distribution

Molecular Weight Design: Adding an appropriate amount of low molecular weight substances (such as tackifying resins or oligomers) to the main polymer can broaden the molecular weight distribution, improve wettability and interfacial adhesion, thereby enhancing peel strength. For example, introducing low molecular weight tackifying resins into acrylic pressure-sensitive adhesives can significantly improve the 180° peel strength.

Balanced Molecular Weight Distribution: Pressure-sensitive adhesives with similar weight-average molecular weights but wider distributions, due to the increased use of low-molecular-weight components, are more effective at wetting the bonded surfaces while maintaining sufficient cohesive strength to prevent cohesive failure during peeling.

3. Introduction of Polar Monomers

Polar Group Reinforcement: Introducing monomers containing polar groups (such as acrylic acid and acrylamide) through copolymerization can increase the molecular polarity of the pressure-sensitive adhesive, significantly improving peel strength against polar substrates. For example, increasing the amount of acrylic acid can increase the molecular polarity of the copolymer, significantly increasing the 180° peel strength and shear creep retention.

Interfacial Interaction Enhancement: Polar groups can enhance the intermolecular forces at the adhesive interface, improve wetting conditions, increase adhesion work, and simultaneously improve cohesive strength and elastic modulus, further optimizing peel performance.

4. To prevent peel strength from climbing, we recommend Kanglibang KL-6620.

Silicone adhesive for graphite waste membrane application | Silicone adhesive for graphite process membrane coating

Low peel strength silicone pressure-sensitive adhesive, specifically designed for 0 to 10g peel strength

Stable peel strength without creep, faster curing speed

100% solids content, more economical and efficient!

5. Controlling Adhesive Layer Thickness

Thickness Optimization: Adhesive layer thickness has a significant impact on peel strength. Within a certain range, increasing the adhesive layer thickness can improve peel strength, but excessive thickness may lead to cohesive failure. The optimal adhesive layer thickness needs to be determined experimentally to balance peel strength and cohesive strength.

Uniformity Control: Ensure uniform adhesive layer thickness, avoiding localized areas of excessive thickness or thinness to maintain consistent peel strength.

6. Selecting a Suitable Substrate

Substrate Property Matching: The thickness, elastic modulus, and surface roughness of the substrate affect peel strength. For example, harder substrates (such as aluminum foil) experience a faster increase in bending deformation work with increasing thickness, potentially leading to increased peel strength; while softer substrates may experience a slower increase in bending deformation work, resulting in decreased peel strength.

Surface treatment: Cleaning, roughening or applying a primer to the substrate surface can enhance the interfacial adhesion between the pressure-sensitive adhesive and the substrate, thereby improving the peel strength.