How To Stop Rolled PTFE Tape From Sticking To Itself During Long-Term Storage

You open a roll of PTFE high-temperature tape that has been sitting in storage for months. When you try to unwind it, the layers are stuck together. Peeling them apart leaves adhesive residue on the non-stick back side – the tape is ruined.

This problem is called interlayer adhesion or blocking. It happens because of two things: the nature of PTFE and silicone adhesive, plus poor storage conditions. The good news is that it can be prevented – both by how the tape is manufactured and how it is stored.

Aokai PTFE has solved this issue through careful process control. This guide explains why blocking happens and what you can do to avoid it.

Why Does PTFE Tape Block? Two Root Causes

To prevent blocking, you must understand the two mechanisms that cause it.

1. Material properties – PTFE memory and adhesive creep

• Elastic memory of PTFE film: During production, PTFE molecular chains are stretched. When the tape is wound tightly and stored under pressure for months, internal stress slowly releases. The film tries to shrink back, causing the tape to warp or the adhesive to detach.

• Silicone PSA creep: Silicone pressure-sensitive adhesive is not a solid – it is a semi-fluid viscoelastic material. Under sustained pressure and heat, it flows (creeps) microscopically, penetrating into the pores or texture of the non-stick back side. Once that happens, the layers bond permanently.

2. External storage conditions – heat, humidity, and pressure

• Temperature above 40°C: Heat dramatically accelerates adhesive creep. PSA viscosity drops, and flow increases.

• High humidity (>70% RH): Moisture can cause hydrolysis of the adhesive, making the surface tacky and promoting adhesion.

• Mechanical pressure from stacking: Heavy rolls stacked on top of each other squeeze the adhesive layer against the back side of the next layer, forcing physical bonding.

The Manufacturing Solution – Gradient Winding Tension

The single most important factor in preventing blocking is how the tape is wound during production.

1. The principle – tight outside, loose inside

If a roll is wound with constant high tension throughout, the inner layers (near the core) are under sustained compressive stress. After months of storage, that stress pushes the adhesive into the back side.

With gradient winding tension:

• Outer layers: wound tightly (to keep the roll compact)

• Inner layers: wound progressively looser (to minimize residual pressure on the core)

Result: the core experiences almost no sustained pressure, so adhesive creep is virtually eliminated.

2. How it is done – closed-loop tension control

Aokai PTFE uses a closed-loop tension control system:

• Sensors monitor the real-time roll diameter

• Controller calculates the required tension using proprietary formulas

• Actuators (variable-frequency or torque motors) dynamically adjust the tension as the roll builds

The winding tension decreases gradually from the inner ring to the outer ring. This also prevents tight-set rolls (where the inner layers become so compressed that they are difficult to unwind).

Additional Production Measures – Beyond Winding

Gradient tension is the core, but other manufacturing steps also help.

1. Choose the right materials

• High-cohesion silicone PSA: Less prone to creep under pressure and heat.

• Extruded PTFE film: Has lower molecular orientation stress than skived film, reducing elastic memory effects.

2. Apply a release coating to the back side

Treat the non-adhesive side of the substrate with a fluorosilicone release coating or primer. This lowers the surface energy of the back side, making it much harder for the adhesive to bond to it.

3. Add physical isolation for thick adhesive grades

For tapes with very thick adhesive layers (>0.05mm), interleave release paper or release film between layers. This is a fail-safe measure for long-term storage (over 12 months).

Proper Storage – Your Responsibility After Purchase

Even the best-manufactured tape can block if stored incorrectly. Follow these rules.

1. Environmental control – keep it cool and dry

2. Handling and stacking – no heavy pressure

• Place rolls horizontally (on their side) on racks. Never stand them upright – this can cause edge deformation.

• Use storage racks for bulk stock. Do not stack rolls more than 3-4 high – the bottom rolls will experience excessive pressure.

• Rotate rolls quarterly – change the stress-bearing position by moving bottom rolls to the top.

• Keep original packaging intact – the plastic wrap protects against dust and humidity. If damaged, re-seal immediately with plastic film.

3. What to do with existing rolls that may already be at risk

If you have rolls that have been stored in poor conditions (hot, humid, stacked high), test a small sample before putting them into production. Unwind 1-2 meters and check for:

• Unusual resistance when unwinding

• Adhesive residue on the back side

• Visible deformation of the roll core

If you detect any of these, warm the roll gently (30-40°C for a few hours) before unwinding – the adhesive may soften enough to release cleanly. But for critical applications, replace the roll.

Summary – A Complete Anti-Blocking Checklist

Aokai PTFE manufactures PTFE high-temperature tape with gradient winding tension as standard. For long-term storage (over 6 months), we recommend additionally sealing rolls in moisture-barrier foil bags and storing in climate-controlled conditions. Contact us for custom packaging options.

The above content is provided by Jiangsu Aokai New Materials Technology Co., Ltd.

If you need further information on specifications, application scenarios and customized solutions for our full product line, including PTFE high-temperature fabrics, PTFE high-temperature tapes, PTFE mesh belts, seamless bonding machine belts, single-sided PTFE cloth, high-temperature resistant conveyor belts and high-temperature resistant fiberglass fabrics, please contact us:

• Mr. Guo: +86 18944819998

• Mr. Liu: +86 13705266308

We adhere to the philosophy of professionalism and integrity, and strive to provide you with one-stop solutions and considerate services.