Interfacial microbubbles in Kapton (polyimide) film lamination

Microbubbles that are difficult to distinguish with the naked eye appear at the interface between the polyimide film and the substrate. This defect is usually found after demolding of the product or during cross-section inspection, mostly concentrated in thick-walled regions or at the end of resin flow. Internal defects reduce the mechanical strength and compactness of the product, with particularly severe impact on products with pressure-bearing and sealing requirements.

(1) Material pretreatment aspect: Water molecules adsorbed on the surface of PI film cannot be completely removed, Moisture vaporizes at high temperature to produce gas or participates in side reactions, causing internal defects in the product. (2) Process factor: Hydrolysis and vaporization during high-temperature lamination, This factor affects the '2079851475616104453 and final quality of the product. (3) Material aspect: Volatile content or moisture in the raw material exceeds the standard, vaporizing at molding temperature to form bubble sources. (4) Process aspect: Air is entrained during filling or pouring, and venting/degassing measures are insufficient. (5) Mold aspect: The cavity venting structure is designed unreasonably, and gas cannot be effectively discharged.

(1) Material selection: Before use, PI film is completely dehydrated and degassed under vacuum above 300°C, Establish material selection evaluation criteria, and determine the optimal solution through comparative tests. (2) Material selection: Store in a nitrogen cabinet before use., Establish material selection evaluation criteria, and determine the optimal solution through comparative tests. (3) Process intensification: Adopt vacuum-assisted casting or vacuum degassing processes to ensure no residual bubbles in the casting liquid. (4) Operation optimization: Reduce the casting speed, adopt bottom feeding to avoid air entrainment, and reasonably set vent grooves. (5) Preventive measure: Establish standardized degassing and casting operating procedures, regularly train operators, and check the first piece of each shift to confirm no bubble defects.

The essence of this problem is that gas was not effectively removed during the lamination '2079851475616104453; it needs to be solved coordinately from three aspects: degassing process, casting method, and venting design.