PTFE High-Temperature Tape for FPC Hot Press Lamination Defect Prevention

As a professional manufacturer of PTFE high-temperature tape, Jiangsu Aokai New Materials gives you a detailed explanation. In the hot press lamination process of Flexible Printed Circuit Boards (FPC), PTFE high-temperature tape addresses two key defects — substrate wrinkling and adhesive transfer — through the combined effects of inherent material properties (low surface energy, high dimensional stability) and optimized processing technologies (stacking structure design, parameter control). It serves as an ideal clean isolation layer and pressure equalizing buffer layer.

I. Causes of Substrate Wrinkling and Adhesive Transfer

Substrate WrinklingThe root cause lies in uneven heat and pressure distribution. FPC is composed of multiple materials such as PI film, copper foil and adhesives with different coefficients of thermal expansion (CTE). In addition, circuit board design factors including uneven copper thickness and stiffener steps will lead to uneven pressure distribution. Non-uniform heat and pressure induce internal material stress, resulting in wrinkling, warping and delamination.

Adhesive Transfer (Residual Adhesive)This is mainly caused by interface and material defects. The semi-cured adhesive of cover film for lamination melts and flows under high temperature, and adheres to the surface of isolation materials. Meanwhile, if the silicone pressure-sensitive adhesive coated on the back of PTFE tape has insufficient temperature resistance or mismatched process parameters, cohesive failure will occur at high temperature, causing partial adhesive transfer onto the FPC surface.

II. Core Mechanisms of PTFE High Temperature Tape for Defect Prevention

Prevention of Substrate Wrinkling

Thermal shock isolation & uniform pressure distributionIn the standard stacking structure: Hot plate → PTFE tape → silicone cushion → FPC → PTFE tape → Hot plate, PTFE tape acts as a release layer. Its stable thermal conductivity ensures uniform heat transfer. Cooperating with silicone buffer cushions, it relieves stress caused by differential thermal expansion and balances overall pressure, avoiding local stress concentration and subsequent wrinkling. For high-precision production, glass-fiber reinforced PTFE tape with low CTE is recommended for superior dimensional stability.

Stable thermal processing windowThe PTFE layer blocks direct thermal impact. Combined with the thermal hysteresis of silicone cushions, heat conduction becomes gentle and stable. It controls the interlayer temperature difference within ≤ 5~7 ℃ during adhesive gelling, enabling complete air exhaust before steady adhesive curing, and fundamentally eliminating wrinkling caused by premature gelling and delayed exhaust. The heating rate of the main temperature rise section is recommended to be controlled at 4.5~5.0 ℃/min.

Elimination of Adhesive Transfer

Non-stick property with ultra-low surface energyPTFE features extremely low surface energy (＜18 mN/m), far lower than that of molten resin and adhesives. With excellent non-stick performance similar to non-stick cookware, it can be peeled off easily after lamination without scratching FPC substrates or leaving residual glue.

High-performance adhesive system selectionTo avoid self-adhesive transfer of the tape, PTFE tape formulated with high-quality silicone pressure-sensitive adhesive shall be adopted. Premium silicone adhesive maintains stable performance at up to 260 ℃, ensuring zero residual glue in long-term continuous production. The temperature resistance grade shall fully meet process requirements (210–260 ℃).

Complete Curing of AdhesivesDuring coating and production of Aokai PTFE tape, improper curing time, temperature or running speed will lead to incomplete adhesive curing, which further causes residual adhesive problems in subsequent application.

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

If you need further information about product specifications, application scenarios and customized solutions for our full product line, including PTFE high-temperature cloth, PTFE high-temperature tape, PTFE high-temperature mesh belt, seamless fusing machine belt, single-sided PTFE coated fabric, high-temperature resistant conveyor belt and high-temperature resistant glass fiber cloth, please feel free to contact us:

· Hotline: Mr. Guo +86 18944819998

· Hotline: Mr. Liu +86 13705266308

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