热收缩膜是一种常见的包装薄膜。在包装应用中，经常利用它受热收缩的想象，实现贴体效果或者集束包裹；同时利用它保护内容物避免污染或者破坏。受热收缩的原理都是在生产薄膜时，在熔点或者玻璃化温度附件对具有活动性的分子链段进行取向，然后冷却到结晶点或玻璃化温度以下，快速固化分子取向；当重新加热到熔点或玻璃化温度以上时，高分子链段会重新具有活动性，原本取向的分子链段开始蜷曲、接取向，宏观上表现为薄膜收缩。 Thermally shrinkable film is a common packaging film. In packaging applications, often use the imagination of the heat contraction to achieve the texture effect or cluster package. Use it to protect content from contamination or damage. Thermal contraction principle is in the production of thin film, the melting point and glass transition temperature attachment to orientation with active molecular chain segment, and then cooled to crystal point or below the glass transition temperature, fast curing molecular orientation; When reheated to or more than glass transition temperature, melting point of polymer chain segment will have active again, the original orientation of molecular chain segments start curled up, orientation, on the macro performance for film contraction.