自1830年第一批罐头食品在商店出售后又过了60年才在消费者的眼中成为确认的包装品,虽然20世纪的销售要求与上个世纪相当不同,但还有相同之处。在美国蒸煮袋最初用于为战场上军队提供食品,这种蒸煮袋是用三层复合的材料制成的软质容器,最外层是聚酯薄膜,中间一层是铝箔,里层是聚丙烯薄膜。由于在越南战争中使用这种袋 Sixty years after the first batch of canned food was sold in stores in 1830, it became a confirmed packaged product in the eyes of consumers. Although the twentieth-century sales requirements were quite different from those of the last century, there were similarities. In the United States, cooking bags were originally used to provide food to the army on the battlefield. The cooking bag was a soft container made of three layers of composite material. The outermost layer was a polyester film. The middle layer was aluminum foil and the inner layer was poly Acrylic film. Due to the use of this bag during the Vietnam War