压延双向拉伸膜的应用和发展

压延双向拉伸薄膜目前在国内得到空前发展，几乎在各个领域都有应用。本文介绍了压延双向拉伸膜在国内的发展与应用。     

PVC压延双向拉伸膜生产技术

随着大棚膜、灯箱膜、土工膜的广泛使用，压延双向拉伸设备也获得迅速发展。生产双向拉伸膜，具有设备投资少、薄膜强度高、透明度好、幅宽大、耐热、耐老化等特性。因而在工业、农业、广告装饰及人们日常生活中得到广泛的应用。     

双向拉伸聚丙烯薄膜的生产工艺研究

介绍了双向拉伸聚丙烯(BOPP)薄膜的生产方法及工艺流程,分析了原材料、纵横拉伸比、温度等因素对BOPP薄膜物理、力学性能的影响,并且对生产中常见的问题进行了分析,提出了解决铸片常见缺陷及拉伸破膜的方法。     

瑞安成为塑料薄膜生产基地

近年来,浙江省瑞安塑料行业投入8亿多元资金,先后从日本引进双向拉伸聚丙烯薄膜生产线4条、四辊异径辊聚氯乙烯压延膜生产线11条,新增国内名牌聚氯乙烯压延膜生产线20条。现有设备中,25%以上具有世界先进水平,50%具有国内领先水平。2002年,瑞安塑料薄膜的生产总量占浙江省塑料薄膜产量的44.3%,占全国塑料薄膜产量的10%,被中国轻工业联合会和中国塑料加工工业协会认定为“中国塑料薄膜生产基地”。瑞安成为塑料薄膜生产基地     

双向拉伸塑料薄膜的发展趋向

近年来为了适应高质量双向拉伸塑料薄膜的生产和节省劳动力 ,双向拉伸机械装备的硬件和软件两个方面均有改进。双向拉伸加工可使塑料薄膜增加新的物理性能 ,包含提高机械强度、弹性模量 ,耐冲击和耐折叠性 ,尺寸稳定性 ,透明度和光泽 ,保湿 (或抗潮 )性、气体阻隔性 ,耐寒性以及耐油性等。如果在加工过程中作一定的热处理 ,双向拉伸薄膜能出现热收缩性 ,可用作收缩包装材料。几种主要的双向拉伸薄膜有双向拉伸聚乙烯薄膜、双向拉伸聚丙烯薄膜、双向拉伸聚苯乙烯薄膜、双向拉伸聚偏二氯乙烯薄膜、双向拉伸聚酯薄膜、双向拉伸尼龙薄膜、双向拉…     

薄膜的双向拉伸技术

本文叙述了双向拉伸薄膜的发展情况及性能特征,讨论了成型方法的选择,论述了加工工艺要求及加工设备特点。在当今的日常生活中,从一般的包装品到工业用品,都离不开各种各样的塑料薄膜,其中以双向拉伸薄膜最为突出。这种薄膜具有优良的综合性能,加工设备的大型、节能化使得所生产的双向拉伸薄膜费用进一步降低,薄膜的使用范围进一步扩大.用于生产双向拉伸膜的原料有 PS,PVC,PVDC,PE,PP,PET,PA,PVA,PVF等。薄膜经过双向拉伸,能够提高其拉伸强度、拉伸弹性横量、冲击强度、断裂强度等机械性能,也能改善其耐热性、耐寒性、气密性、透明性、光泽性等,所以特别适应于包装行业的应用。生产双向拉伸薄膜的方法有同时双向拉伸法和逐次双向拉伸法两种,但实际生产中后者得到更广泛的应用,因而本文也主要介绍后者的有关技术问题。     

双向拉伸无滴大棚膜生产技术

叙述了PVC压延双向拉伸无滴大棚膜生产技术。     

浅析合成BOPP薄膜的反应及性能

分析了双向拉伸聚丙烯(BOPP)薄膜生产过程中的取向和结晶对薄膜机械力学性能和光学性能的影响,实际生产中生产工艺应该根据PP的热力学特性相应调整,以制造出双向取向度高,同时结晶微细、均匀的高性能优质双向拉伸聚丙烯薄膜。     

合成BOPP薄膜的反应及性能研究

分析了双向拉伸聚丙烯（BOPP）薄膜生产过程中的取向和结晶对薄膜机械力学性能和光学性能的影响,实际生产中生产工艺应该根据PP的热力学特性相应调整,以制造出双向取向度高,同时结晶微细、均匀的高性能优质双向拉伸聚丙烯薄膜。     

低成本生产高端双向位伸薄膜

薄膜生产厂商们已通过使用线性电机或机械系统的拉伸设备,以及实验室拉伸机开发出了多种高质量的双向拉伸薄膜。在这些拉伸系统中,尤以以机械方式运行的第二代同步拉伸系统更为引人瞩目,因为该系统为低成本生产高端双向拉伸薄膜提供了新的机会。     

PET薄膜双向拉伸技术及发展方向

采用双向拉伸技术制得的聚酯薄膜具有拉伸强度高、光学性能好、厚度均匀、产能大、生产效率高等特点,双拉技术已得到普遍的应用。介绍了双向拉伸的原理、工艺、设备及双向拉伸技术的发展方向。     

BOPP的生产与市场分析

对双向拉伸聚丙烯薄膜的生产和市场情况进行了分析，重点对国内功能性薄膜产品进行总结，以期对生产提供参考。     

Mechanical properties of biaxially oriented poly(vinyl chloride)

This report describes the influence, of (a) degree of biaxial orientation, (b) stretching rate, and (c) stretching temperature on the tensile, dynamic mechanical and dielectric properties of non-impact modified PVC. A new parameter designated “planar strain” is used to correlate anisotropic property values with both equal and unequal biaxial stretching in a single two-dimensional plot, thereby providing a direct comparison of the effects of two or more biaxial stretching ratios. It is shown that optimum stretching conditions depend to some extent upon end use and that a 2 × 2 stretch ratio is optimum for impact resistance. The actual property/processing condition relationships exhibit very complicated interactions and are correlated empirically in this study. The dynamic measurements suggest that overall local segmental beta motion is increased after orientation but that the relative chain alignment makes it more difficult to activate this motion.     

布管法双向自增强管材连续扩胀装置的实验研究

采用布管法连续扩胀装置加工了聚氯乙烯（PVC）环向扩胀管和双向自增强管。实验结果表明,直径从40 mm扩胀到50 mm的环向扩胀管的环向拉伸强度提高了23 %～25 %,环向弹性模量提高了12 %。双向自增强PVC管的环向拉伸强度提高了26 %～33 %,弹性模量提高了30 %～33 %。通过对不同轴向拉伸比的双向自增强管的拉伸强度比较发现,随着轴向拉伸比的增加,环向拉伸强度逐渐提高。，环向弹性模量提高12%。双向自增强PVC管的拉伸强度提高了26%-33%，弹性模量提高了30%-33%。通过对不同轴向拉伸比双向自增强管的拉伸强度比较发现，随着轴向拉伸比的增加，环向拉伸强度逐渐提高。     

压延存料对PVC透明片材质量影响的探讨

根据G.Ardichuili的压延理论,分析了聚氯乙烯压延加工过程中物料的流变行为,指出存料是影响压延透明片材的厚度均匀性、外观质量的重要因素之一。根据产品的厚度、柔软率,正确控制辊隙存料量是提高压延透明片材质量的重要手段之一。     

PVC压延双向拉伸膜生产技术

介绍了生产灯箱膜、大棚膜、土工膜及其它大型膜类的压延双向拉伸设备及生产工艺。     

Uni- and biaxial stretching of chlorinated pvc sheets. A fundamental study of thermoformability

Chlorinated PVC is superior to unmodified PVC as a thermoplastic for use in thermoforming, especially if improved heat resistance and dimensional stability are required. In the present report, results tire given of a fundamental experimental study on the thermoformability of CPVC sheets obtained by calendering various formulations based on CPVC resins with at least 65 percent chlorine content. Extensibility as well as the relationship between stress and strain in uni- and biaxial stretching have been determined as a function of temperature and rate of stretching by means of specially devised, highly instrumented laboratory equipment. Stress-strain relations under isothermal conditions and at constant strain rate are compared for the two modes of stretching, and the difference in behavior between PVC and CPVC, particularly with regard to the effect of temperature, is emphasized. Internal stresses frozen in during cooling, following rapid stretching at appropriate thermoforming temperatures, have been determined by means of a detailed analysis of retractive force measurements. The relationship between internal stress and molecular orientation is discussed as well as the effect of the latter parameters on various properties of technological interest: dimensional stability, impact resistance, and gas permeability.     

Studies on the stretching of polypropylene film. II. Polyaxial stretching

Polypropylene film was stretched polyaxially at 100–160°C., and the orientation behavior was studied by means of optical and x-ray method. The molecular chains oriented progressively to the film surface with an increase in stretching area v_A in the range 1–16, and the (040) selective uniplanar orientation developed at the extreme stretching. The plot of orientation versus v_A was less steep when the stretching was carried out at higher temperature, but the final degree of orientation was independent of the temperature, because the final v_A increased with temperature. At 160°C. premelting occured to such a degree that the high stretching and, consequently, the high orientation could not be obtained. The orientation of the amorphous chains was always behind that of the crystalline region. In the initial stage the polyaxial stretching was not as effective in attaining high biaxial orientation as the two-step biaxial stretching, but the final orientation was the same in both types of stretching because v_A reached a value of 16 in the polyaxial stretching while it was only 2 in biaxial stretching.     

半柔性PVC地板块加工技术

介绍了在压延成型基础上通过在热料带上撒上预先配制好的着色粒料，然后经压延机压延生产出具有大理石花纹的ＰＶＣ半柔性地板块的加工工艺     

PVC粮食储藏膜的研制

粮食储藏膜是目前粮库储藏粮食、减少虫害必不可少的材料，粮膜必须具有气密性好、防潮、耐低温、透氧率低、韧性好、拉力强、透明度高的特性，产品要均匀度好、手感柔软、爽滑、不易吸尘、抗老化性能优异、杀虫效果好、使用寿命长。产品幅宽可达6米，可广泛用于各种粮库、粮垛的粮食储存，可使粮食达到防潮、防霉保鲜的效果。“膜下环流熏蒸”技术对粮堆采取了薄膜密闭，减小害虫感染几率，使“低氧无药”绿色储粮成为可能，经济效益更佳。另外，环流熏蒸杀虫技术减少药剂残留，降低粮食损耗，提高粮食品质，可增强企业储藏产品的竞争力，无形中创造了潜在的经济效益。“膜下环流熏蒸”可以将磷化氢（PH3）的损失降低到最低限度。仓房泄漏是损失PH3的重要原因，良好的密封是PH3熏蒸是否成功的关键，而使用PVC粮膜覆盖则是达到这一目的的有效方法之一。