PTFE high-temperature cloth (PTFE-coated fiberglass) can be manufactured using two fundamentally different approaches: single-dip impregnation and multi-dip impregnation. The choice between them determines coating thickness, surface quality, performance level, and cost.
In a single-dip process, the fiberglass fabric passes through just one complete impregnation-drying-sintering cycle. In a multi-dip process, it undergoes repeated cycles – typically 2-3 runs up to over a dozen – building up PTFE layer by layer.
Aokai PTFE uses both processes depending on the application. This guide explains the definition, process flow, characteristics, and typical applications of each, along with a side-by-side performance comparison.
Single-Dip Impregnation Process – Fast and Cost-Effective
1. Definition and process flow
Definition: Fiberglass fabric goes through only one complete cycle of impregnation-drying-sintering to produce the finished PTFE-coated cloth.
Process flow: Fiberglass fabric → impregnation with PTFE dispersion → squeeze-off/doctor-blade coating to control resin pickup → low-temperature drying for water removal → high-temperature sintering (360-400°C) to melt PTFE into a continuous film → cooling and winding-up.
2. Process characteristics
Resin pickup is limited, yielding thin-gauge, low-grammage fabric
The woven texture of fiberglass cannot be fully filled, resulting in a rough surface with micro-pinholes
Incomplete PTFE coverage leads to relatively low tensile strength, dielectric strength, chemical-penetration resistance, and non-stick performance
The production cycle is short with high efficiency and low manufacturing cost advantages
3. Typical applications
Single-dip cloth is adopted for scenarios with low requirements on thickness, impermeability, and surface smoothness:
Low-grade insulating gaskets
Temporary non-stick mats
Semi-permeable materials that retain partial air permeability
Non-critical industrial uses where cost is the primary driver
Multi-Dip Impregnation Process – Layer-by-Layer Performance Build-Up
1. Definition and process flow
Definition: The fiberglass substrate undergoes repeated cycles of impregnation-drying-sintering, normally ranging from 2-3 runs up to over a dozen cycles. Each subsequent layer is deposited on the existing PTFE coating to build up thickness, fill voids, and repair surface defects.
Process flow: Fiberglass fabric → 1st impregnation → drying → sintering → cooling → 2nd impregnation → drying → sintering → cooling → 3rd impregnation … Final winding-up once the target thickness, grammage, and performance specifications are achieved.
Single-dip impregnation is a fast thin-film coating method featuring short production cycles and low costs, yet limited by rough surface finish and inferior protective performance.
Multi-dip impregnation is a layer-by-layer infiltration and build-up technique that fully encapsulates the fiberglass substrate. It produces smooth, dense PTFE-coated fabric with premium-grade performance at the expense of complex workflows and higher costs.
Aokai PTFE manufactures both single-dip and multi-dip PTFE cloth. For demanding industrial applications, nearly all high-performance PTFE-impregnated fiberglass fabrics are produced via the multi-dip process. Contact us to discuss which grade suits your application requirements.
If you would like to obtain detailed technical parameters, application cases and customized solutions for our full-range product lineup, including PTFE high-temperature cloth, PTFE high-temperature adhesive tape, PTFE high-temperature mesh belt, seamless heat-press belt, single-sided PTFE fabric, high-temperature-resistant conveyor belt and heat-resistant fiberglass cloth, please get in touch via the contact information below:
