1. Core Definition and Functional features
Grid release film is a release film with a grid texture on its surface. It reduces the contact area with the tape by raising the grid, enhancing the release effect. Meanwhile, the grid structure enables an automatic exhaust function to prevent the formation of bubbles during lamination. Typical specifications include a thickness of 50-150μm and a width of 1080mm (customizable). The grid shape can be designed as square, rhombus or hexagonal. The grid size range is 0.05mm-2.0mm, with a spacing of 0.03mm-0.3mm and a height of 0.003mm-0.05mm. Its core functions include:
Release performance: Achieve a peel force as low as 0.1N/25mm through silicone oil, fluoroplastic or non-silicone coatings (light peel type), meeting the repeated peel requirements of high-viscosity adhesive tapes.
Exhaust function: The grid structure guides air to be discharged during bonding, enhancing bonding efficiency and surface flatness. It is particularly suitable for scenarios such as electronic components and building curtain walls.
Protection and support: It serves as a temporary protective layer in the processing of adhesive products and electronic materials to prevent contamination or damage, while also supporting complex structural components.
2. Principles of material selection and compatibility
Substrate system
PET/PI/BOPP: The thickness of the PET substrate is 25-125μm, taking into account both mechanical strength and cost. PI can withstand high temperatures of ≥200℃ and is suitable for flexible circuit boards. BOPP is low-temperature resistant and suitable for the packaging field.
Specialized substrates: such as PEEK for extreme environments, paper substrates for low-cost scenarios, and PE/CPP composite films for enhancing flexibility.
Coating material
Silicone oil release agent: solvent-based or solvent-free, coating amount 0.8-1.5g/m², forms a stable release layer after curing, with a temperature resistance of up to 180℃.
Fluoroplastic coating: Extremely low coefficient of friction, resistant to chemical corrosion, suitable for high-viscosity silicone protective films.
Non-silicon release agent: Moderate peel force, resistant to chemical corrosion, suitable for complex environments.
Functional coatings: Anti-static treatment (surface resistance ≤1×10⁶Ω), UV-cured coating for enhanced weather resistance, and nano-alumina for improved temperature resistance.
3. Processing technology and technological innovation
Forming process
Coating technology: The resin grid layer is transferred and coated by an anilox roller, and the silicone release agent is micro-concave coated. The coating accuracy is ±0.1g/m². The curing methods include thermal curing or UV curing (energy ≥300mJ/cm²).
Embossing process: A grid texture is formed on the surface of the substrate through an embossing roller, and combined with halo treatment to increase the surface tension (≤30mN/m), ensuring the adhesion of the coating.
Composite process: Multi-layer structure such as PET+ silicone oil release layer + resin grid layer, is compounded under pressure through a composite wheel, and then trimmed and wound after cooling.
Process parameter control
Grid parameters: Length 0.05mm-2.0mm, spacing 0.03mm-0.3mm, height 0.003mm-0.05mm, hardness 50-70A.
Curing conditions: Drying temperature 60-145℃, curing time 30-70m/min, ensuring uniform coating without defects.
Tension control: The unwinding/rewinding tension is ≤50N to prevent the base material from stretching and deforming.
4. Quality control and inspection standards
Key performance indicators
Peel force: Light peel type ≤0.1N/25mm, heavy peel type 0.5-2.0N/25mm (180° peel, GB/T 2792).
Residual adhesion rate: ≤1.0% (UV spectrophotometric method), ensuring no residue after peeling.
Thickness uniformity: deviation ≤±5% (thickness gauge, GB/T 6672), surface roughness Ra≤0.8μm.
Temperature resistance: The peel force change rate after 150℃ for 1 hour is ≤±20% (GB/T 1735), and there is no crack at -40℃ for 24 hours (ISO 4649).
Resistance to wet heat aging: No coating peeling or substrate deformation after 500 hours at 85℃/85% RH.
Environmental protection and safety: Solvent residue toluene/ethyl acetate ≤5mg/m² (GC-MS method), heavy metal migration complies with EN 71-3 standard, RoHS certification ensures harmless substances.
Testing methods: In accordance with standards such as GB/T 25256, ASTM D3330, ISO 29862, etc., means such as three-coordinate measurement, spectral analysis, and weather resistance test are adopted.
5. Application scenarios and typical cases
Electronic manufacturing: It is used for the protection of flexible circuit boards (FPC), MLCC release films, and LCD light guide plates. For instance, the 5G antenna flexible circuit board adopts PI substrate + nano-alumina coating, with a temperature resistance of 180℃ and a peel force of 0.08N/25mm.
Architecture and decoration: PTFE mesh membranes are used on the facades of sports venues and commercial centers. For instance, the first shopping mall in Shanghai's West Hongqiao District adopts B1 flame-retardant mesh membranes with a 28% opening rate to achieve a semi-transparent effect and provide shading and heat insulation.
Automotive industry: TPU car wrap release film and heat insulation film, with stable release force maintained at high temperatures, are compatible with the TPU base film casting process.
Packaging and medical care: PET mesh protective film is used for food packaging and medical equipment, such as surgical instrument protective layers. It has strong weather resistance and leaves no residue.