摘要 |
An improved blown-film extrusion process with particular application for high modulus thermoplastic resins. A cylinder is mounted above the cooling air ring. The film bubble passes through this cylinder, which has a diameter approximating the final diameter of the bubble. The frost line remains at or slightly higher than the top of the cylinder, leaving a small gap between the top of the cylinder bubble. The improvement enhances bubble cooling and stability and results in wrinkle-free film.
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