Why Do Bubbling & Delamination Occur on Products When Using Non-Stick Tapes for Hot Plates of Rubber Vulcanizing Presses & Hot Press Machines?

Jiangsu Aokai New Materials, a professional manufacturer of PTFE high-temperature fabrics, offers professional analysis for you. In the vulcanization and hot pressing forming processes of rubber products, hot plate sticking, product bubbling and delamination are two major long-standing production problems. For hot plate anti-sticking treatment, PTFE high-temperature tape is currently recognized by the industry as an efficient, clean and cost-effective solution.

It should be particularly noted that the “tape bubbling and delamination” encountered during vulcanization generally refers to internal defects of rubber products such as conveyor belts and transmission belts, rather than delamination of the PTFE high-temperature tape itself. If the PTFE tape itself delaminates, it is usually caused by product quality defects or over-temperature operation. Combined with the application of PTFE high-temperature tape as an auxiliary material, we analyze the causes of product defects and corresponding solutions as follows:

1. Correlation Between Poor Ventilation and Product Bubbling

During the vulcanization of rubber products (e.g., conveyor belts), moisture and low-molecular volatile substances inside the rubber compound must be fully discharged. If no PTFE high-temperature tape is laid on the hot plate surface, the rubber material will stick firmly to the hot plate. Trapped gas can only flow horizontally and is easily enclosed between material layers, forming air bubbles.

Solutions:Although PTFE high-temperature tape features excellent release performance, its overly smooth surface may block gas escape channels when vulcanizing thick-walled products. It is recommended to use perforated PTFE high-temperature tape or reserve vent grooves when laying the tape. PTFE tape only provides a non-stick surface, and it must be used together with standardized ventilation processes such as multiple pressure relief cycles to ensure sufficient degassing.

2. Product Delamination and Interfacial Bonding Strength

Delamination is mainly caused by release agent contamination between rubber layers. When talcum powder, silicone oil and other traditional anti-sticking agents are used, they are prone to drifting onto the bonding joints of rubber materials, forming a weak interfacial layer and resulting in interlayer separation.

Anti-cross Contamination Advantage of PTFE High-Temperature Tape

As a solid film protective layer for hot plates, PTFE high-temperature tape will not drift or scatter like powder or liquid release agents. It greatly reduces the risk of poor interlayer adhesion caused by floating anti-sticking contaminants. Therefore, replacing liquid release agents with PTFE high-temperature tape is an effective way to eliminate delamination risks at the source for manufacturing high-quality rubber products.

3. Correct Use and Maintenance of PTFE High-Temperature Tape

To maximize the service performance and service life of PTFE high-temperature tape, please follow the operating specifications below:

· Wipe the hot plate surface with alcohol to remove oil and dirt before pasting the tape;

· Keep the lap joints of the PTFE tape flat to avoid indentation transfer to finished products;

· Replace the tape in a timely manner if residual rubber scale appears on the surface and the tape turns sticky, which indicates the end of its service life.

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

We supply a full range of products, including PTFE high-temperature cloth, PTFE high-temperature tape, PTFE high-temperature mesh belts, seamless fusing machine belts, single-sided PTFE coated fabrics, high-temperature resistant conveyor belts and high-temperature resistant fiberglass cloth.For detailed product parameters, application cases and customized solutions, please feel free to contact us:

· Mr. Guo: +86 18944819998

· Mr. Liu: +86 13705266308

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