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首页> 外文期刊>Journal of Applied Polymer Science >Shrinkage behavior after the heat setting of biaxially stretched poly(ethylene 2,6-naphthalate) films and bottles
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Shrinkage behavior after the heat setting of biaxially stretched poly(ethylene 2,6-naphthalate) films and bottles

机译：双轴拉伸聚2,6-萘二甲酸乙二醇酯薄膜和瓶子热定形后的收缩行为

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Amorphous preforms of poly(ethylene 2,6-naphthalate) (PEN) were biaxially drawn into bottles up to the desired volume under industrial conditions. These bottles were used to characterize the shrinkage behavior of the drawn bottles with or without heat treatment and to study structural variations during heat setting. During drawing, a rigid phase structure was induced, and the amount of the induced rigid phase structure was linearly related to the square root of the extra first strain invariant under equilibrium conditions. During the production of these bottles, this equilibrium was not attained because of high stretching conditions and rapid cooling after stretching. The structure after orientation contained a rigid amorphous phase and an oriented amorphous phase. The shrinkage behavior was a function of the temperature and time of heat setting. Long heat-setting times, around 30 min, were used to characterize the possible structural variations of the oriented PEN after heat setting at equilibrium. Under the equilibrium conditions of heat setting, the start temperature of the shrinkage was directly related to the heat-setting temperature and moved from 60degreesC without heat treatment up to a temperature of 255degreesC by a heat-setting temperature of 255degreesC; this contrasted with poly(ethylene terephthalate) (PET), for which the start temperature of shrinkage was always around 80degreesC. For heat-setting temperatures higher than 220degreesC, the structural variations changed rapidly as a function of the heat-setting time, and the corresponding shrinkage of the heat-set samples sank below 1% in a timescale of 30-60 s for a film thickness of 500 mum. The heat treatment of the oriented films taken out of the bottle walls with fixed ends stabilized the induced structures, and the shrinkage of these heat-set films was zero for temperatures up to the heat-setting temperature, between 220 and 265degreesC, if the heat-setting time was sufficient. According to the results obtained, a heat-setting time of 30 s, for a film thickness of 500 mum, was sufficient at a heat-setting temperature of 255degreesC to stabilize the produced biaxially oriented PEN bottles and to take them out the mold without further shrinkage. During the drawing of PEN, two different types of rigid amorphous phases seemed to be induced, one with a mean shrinkage temperature of 151degreesC and another rigid amorphous phase, more tempera ture-stable than the first one, that shrank in the temperature range of 200-310degreesC. During heat setting at high temperatures, a continuous transformation of the less stable phase into the very stable phase took place. The heat-set method after blow molding is industrially possible with PEN, without the complicated process of subsequent cooling before the molds are opened, in contrast to PET. This constitutes a big advantage for the blow molding of PEN bottles and the production of oriented PEN films. (C) 2002 Wiley Periodicals, Inc. [References: 28]
机译：将聚（2,6-萘二甲酸乙二醇酯）（PEN）的非晶形预成型品在工业条件下双轴拉伸到瓶中，直至达到所需的体积。这些瓶子用于表征经过或不经过热处理的拉伸瓶子的收缩行为，并研究热定形过程中的结构变化。在拉伸过程中，诱导出刚性相结构，并且在平衡条件下，诱导的刚性相结构的数量与额外的第一应变不变的平方根线性相关。在这些瓶子的生产过程中，由于高拉伸条件和拉伸后的快速冷却，未达到该平衡。取向后的结构包含刚性非晶相和取向非晶相。收缩行为是温度和热定型时间的函数。较长的热定型时间（约30分钟）用于表征平衡状态下热定型后定向PEN的可能结构变化。在热定型的平衡条件下，收缩的起始温度与热定型温度直接相关，并且在不进行热处理的情况下从60℃上升到255℃的热定型温度，达到255℃。这与聚对苯二甲酸乙二醇酯（PET）的收缩开始温度始终在80摄氏度左右形成对比。对于高于220摄氏度的热定型温度，结构变化随热定型时间的变化而迅速变化，并且在30-60 s的时间范围内，热定型样品的相应收缩率在薄膜厚度范围内降至1％以下500妈妈从具有固定端的瓶壁中取出的取向膜的热处理使诱导的结构稳定，如果达到热定型温度（如果加热到220至265摄氏度），这些热定型膜的收缩率为零。设定时间就足够了。根据获得的结果，在255℃的热定型温度下，对于500微米的膜厚，30 s的热定型时间足以稳定生产的双轴取向PEN瓶并无需进一步将其从模具中取出收缩。在绘制PEN的过程中，似乎诱发了两种不同类型的刚性非晶相，一种平均收缩温度为151℃，另一种刚性非晶相的温度稳定性比第一种稳定，在200°C的温度范围内收缩-310摄氏度在高温下热定形期间，不稳定的相连续转变成非常稳定的相。与PET相比，吹塑后的热定型方法在工业上可以通过PEN进行，而无需在打开模具之前进行随后冷却的复杂过程。这对吹塑PEN瓶和生产定向PEN膜构成了很大的优势。 （C）2002 Wiley Periodicals，Inc. [参考：28]

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