一般來說,復(fù)合包裝材料的外層材料應(yīng)當(dāng)是熔點(diǎn)較高,耐熱性能好,不易劃傷、磨毛,印刷性能好,光學(xué)性能好的材料,常采用的有紙、鋁箔、玻璃紙、聚碳酸酯、尼龍、聚酯、聚丙烯等。
Generally speaking, the outer layer material of composite packaging materials should be a material with high melting point, good heat resistance, not easy to scratch or grind, good printing performance, and good optical performance. Commonly used materials include paper, aluminum foil, fiberglass, polycarbonate, nylon, polyester, polypropylene, etc.
內(nèi)層材料應(yīng)當(dāng)具有熱封性、粘合性好、無味、、耐油、耐水、耐化學(xué)品等性能,如聚丙烯、聚乙烯、聚偏二氯乙烯等耐熱塑料材料。
The inner layer material should have properties such as heat sealing, good adhesion, odorless, non-toxic, oil resistant, water resistant, and chemical resistant, such as heat-resistant plastic materials such as polypropylene, polyethylene, and polyvinylidene chloride.
三層以上復(fù)合材料的中層通常采用阻隔氣體與水分及遮敝光線等性能好且機(jī)械強(qiáng)度高的材料,如鋁箔、聚偏二氯乙烯、玻璃紙、紙、聚乙烯等。
The middle layer of composite materials with three or more layers usually uses materials with good performance and high mechanical strength, such as aluminum foil, polyvinylidene chloride, glass paper, paper, polyethylene, etc., to block gas and moisture, and to block light.
層與層之間則涂有粘合劑用于粘合。一般外層與中層材料之間使用溶劑型熱固性聚氨酯粘合劑,內(nèi)層與中層之間使用改性聚丙烯乳液粘合劑或用特殊改性的含羰基丙烯共同樹脂等。外層用粘合劑要求粘合強(qiáng)度高、工藝簡單、成本低;內(nèi)層用粘合劑要求耐高溫、剝離強(qiáng)度高、、無味,不影響食品的營養(yǎng)成分,能很好保持食品的色香味。
Adhesive is applied between layers for bonding. Generally, solvent based thermosetting polyurethane adhesive is used between the outer layer and the middle layer, and modified polypropylene lotion adhesive or specially modified carbonyl propylene containing common resin is used between the inner layer and the middle layer. The adhesive used for the outer layer requires high bonding strength, simple process, and low cost; The adhesive used for the inner layer requires high temperature resistance, high peel strength, non-toxic, odorless, and does not affect the nutritional content of the food, which can effectively maintain the color, aroma, and taste of the food.