PTFE Tape Blistering Causes Under High Temperature & Pressure

As a leading manufacturer of PTFE high-temperature tape, Jiangsu Aokai New Materials professionally analyzes why PTFE high-temperature tape blisters under long-term high pressure at 180℃ when applied for anti-stick treatment on hot plates of rubber vulcanizing presses. This defect is jointly caused by material performance, application processes and equipment conditions. An in-depth understanding of the failure mechanism of PTFE high-temperature tape is the core to solving the problem.

I. Material Defects: The Root Cause of Blistering

PTFE high-temperature tape consists of base fabric and adhesive. Any performance defect of either layer will be exposed under extreme high-temperature and high-pressure working conditions.

1. Insufficient temperature resistance of adhesive — the primary cause of blistering
Although the PTFE base fabric features excellent high-temperature resistance, improper adhesive selection will lead to complete failure. To cut costs, some inferior PTFE tapes adopt ordinary acrylic adhesive with a temperature resistance of only 120℃. Such adhesive will soften and decompose rapidly at 180℃, generating gas and eventually causing blistering and bulging.

Even for PTFE tapes coated with silicone pressure-sensitive adhesive, poor glue quality or incomplete curing (insufficient curing time and temperature) will result in severe attenuation of cohesive force under long-term high pressure at 180℃, further triggering blistering or debonding.

1. Composite defects between base fabric and adhesive — inherent hidden danger

In the production process, inadequate surface treatment of PTFE base fabric and poor coating process control will form micro gaps between the base material and adhesive. Under 180℃ high pressure, stress accumulates at these defective areas and induces blistering.

In addition, oil stains, dust and other contaminants on the hot plate surface before pasting will greatly reduce the adhesion of the adhesive, leading to blistering after heating and compression.

1. Internal volatile substances in the tape — latent risk factors

Residual solvents, low-molecular plasticizers and other volatile substances in the tape formula will vaporize sharply and expand in volume at 180℃, jacking up the adhesive layer and forming dense blisters.

Moreover, if the tape is produced or stored in a high-humidity environment, absorbed moisture will vaporize violently at high temperature, which is a common yet easily overlooked factor leading to blistering.

II. Improper Operation Processes Aggravate Defects

1. Non-standard pasting operation directly induces blistering

If the tape is not evenly rolled and pasted from one end to the other to exhaust air, residual air bubbles will expand under vulcanization temperature and pressure, forming obvious bulges.

Uneven tension during pasting and suspended unfitted areas will also become blistering starting points.

2. Inadequate surface cleaning weakens bonding performance

Un-dried hot plates or residual oil, release agent and other contaminants on the surface prevent full adhesion of the tape. Weak bonding areas are bound to blister under high temperature and high pressure.

3.Unreasonable vulcanization parameters increase service load

The actual operating temperature far exceeding 180℃ or excessive local temperature difference of hot plates will exceed the temperature resistance limit of the adhesive and accelerate degradation and blistering.

Insufficient pressing force or delayed pressurization cannot restrain the generation and expansion of air bubbles.

In essence, the blistering of PTFE high-temperature tape reflects the comprehensive stability and application reliability of materials under extreme working conditions of 180℃ long-term high pressure. The problem can be completely solved through reasonable product selection, standardized pasting operation and stable working parameter control.

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

If you need further information on product parameters, application scenarios and customized solutions for our full-range products including PTFE high-temperature fabrics, PTFE high-temperature tapes, PTFE high-temperature mesh belts, seamless bonding machine belts, single-sided PTFE coated fabrics, high-temperature resistant conveyor belts and fiberglass fabrics, please feel free to contact us:

· Mr. Guo: +86 18944819998

· Mr. Liu: +86 13705266308

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