茂金属聚烯烃/PP共混改性研究和易剥离聚丙烯流延薄膜（CPP）的研制

【作者】 陈英；

【导师】 周持兴； 顾红庆；

【作者基本信息】 上海交通大学 ， 化学工程， 2006， 硕士

【摘要】 软包装通常由阻隔膜(BOPP、BOPET、BOPA等)与热封膜(PE、CPP等)复合而成,因其具有的阻隔性,大大提高商品的保质期,并因其方便性和经济性,目前被广泛应用于食品、药品、农业、化工、服装等产品的包装。但软包装袋很不容易被打开,一般需要在包装袋的边缘打上缺口才能打开包装,造成在实际生活当中不易打开包装袋的不便。用易剥离聚丙烯流延薄膜(CPP)制造的软包装具有热封范围宽,热封温度低和热封强度可调的特点,热封后可以直接从热封边打开,大大方便了消费者的使用,但易剥离薄膜目前仅在PE果冻盖上得到广泛应用。聚丙烯流延薄膜(CPP)的热封强度比PE薄膜大得多,易剥离CPP薄膜在国内尚未生产。因此,研制易剥离CPP薄膜具有重要意义。本论文介绍了聚丙烯流延薄膜(CPP)的生产、应用和发展,对茂金属聚烯烃-PP共混改性进行了研究,对茂金属聚烯烃品种、用量对CO-PP的热性能、结晶行为的影响进行了讨论。研究发现聚烯烃弹性体对聚丙烯球晶存在细化分割作用,能降低球晶尺寸。论文进一步对茂金属催化聚烯烃的品种和用量对CPP薄膜热封性能的影响进行了研究。实验结果表明,在热封层中添加M1(乙烯-丁烯共聚物)能明显降低CPP的起始热封温度,同时降低薄膜的热封强度。在热封层中添加M2(丙烯-丁烯共聚物)能降低CPP的热封温度,但对薄膜的热封强度无影响。在确定易剥离CPP薄膜热封改性剂M1后,确定了其比例和剥离强度的关系。研究结果指出,热封改性剂M1在20%以上时具有易剥离效果,在30%时的剥离强度为9.2N/15mm,分离面为CPP对CPP分离。由于热封改性剂的加入影响了CPP薄膜的开口性和摩擦系数,本论文还对影响CPP薄膜的抗粘连剂和爽滑剂进行了选择和试验,在考虑了薄膜的综合性能后选择采用在原热封层配方中添加1500PPm粒径为5um的硅酸盐抗粘连剂和在芯层材料中添加600PPm芥酸酰胺,从而改善了易剥离CPP薄膜的综合性能。开发的易剥离聚丙烯流延薄膜已经实践中应用,并达到用户易剥离包装的要求。更多还原

【Abstract】 Flexible package is usually formed by the compound of barrier films and heat-sealing films. Due to its high barrier properties, Flexible package is helpful to prolong the storage life of products. In addition, the convenience and economy make flexible package be widely used in food, medicine, agriculture, chemical engineering and clothes industries. However, the Flexible package bag is difficult to be unclosed, which causes inconvenience in the actual application. Therefore, a nick is usually needed on the edge of the pack.Flexible package produced by easy-peeling PP cast film has a wide heat sealing temperatures window. Also its actual heat sealing temperatures is relatively low but the heat sealing strength can be under the control. The bag made of this kind of cast PP film can be easily opened from the sealing edge and very convenient for the customers to use it. Until now, the easy-peeling film is only used as the PE cover of jelly. The seal strengths of CPP film is even higher than PE film.Tt is very important to developing easy-peeling CPP film but it has not been produced in our country.In this paper, the production, application and development of the CPP film as well as the related studies on blending modification PP of metallocene polyolefin will be briefly introduced first. Next, influence of different metallocene polyolefin and its content on the thermal capacity and crystallization behavior of COPP will be investigated in details. It is found that adding of a butylene-ethylene copolymer reduces the seal initiation temperatures and also decreases the heat sealing strength. Quite differently, adding anther copolymer composed of propylene and butylene can only reduce the heat seal temperatures but has little effect on the thermal heat sealing strength. Therefore the butylene-ethylene copolymer is a preferable modifier to peelable CPP film. The relation between the content of butylene-ethylene copolymer and film heat sealing strength is studied and it is found that the film has a better peelable feature when the content of modifier is above 20 percent. For example, the peeling strength of the film is up to 9.2N/15mm as for the 30 percent content of the butylene-ethylene copolymer. After peeling, the separated surface is confirmed as between CPPs, which meets the requirement of the consumers.Moreover, the adding of heat sealing modifier also affects the antiblocking and friction coefficient of CPP cast film, then the kind of antiblocking additives and slip agents is carefully chosen and the effect is experimentally investigated. Considering the comprehensive properties of更多还原