聚丙烯熔融指数的影响因素研究

熔融指数也被称之为熔体流动速率,主要反映塑胶类材料在加工过程中表现出来的流动性。聚丙烯属于一种热塑性树脂,在对其加工生产的过程中,有效控制熔融指数,将其控制在允许的范围之内,有助于保障生产加工产品的质量。基于此,围绕聚丙烯熔融指数的影响因素展开探讨,以更好地控制聚丙烯熔融指数,促进聚丙烯生产加工质量提升。     

PVC/PE共混体系的研究—CPE对PVC/LDPE共混物的增容作用

采用氯化聚乙烯(CPE)作为聚氯乙烯(PVC)/低密度聚乙烯(LDPE)共混物的增容剂,用机械共混法制样,研究了共混条件及共混物组成对共混物的力学性能、加工性能、相态结构的影响。研究表明,在120℃下 LDPE 与 CPE 先预混5分钟,再于155℃下将 LDPE、CPE 与 PVC 共混15～20分钟所得到的共混物性能较好。PVC 为主的 PVC/LDPE 共混物中 CPE 较佳用量为5份(相对于100份 PVC)。DTA、扫描电子显微镜(SEM)研究证实了 CPE 的增容作用。此外,熔融指数测定结果表明,共混物中 LDPE 含量增高,共混物的熔融指数增大。     

化学降解法生产高熔融指数聚丙烯的质量控制经验

分析、比较以低熔融指数聚丙烯粉料为基础原料生产纺黏无纺布专用聚丙烯树脂的方法,介绍了通过化学降解法生产高熔融指数聚丙烯无纺布专用料的控制难点。     

食品级LDPE树脂低聚物产生原因分析及改进措施

通过实验和理论分析研究食品级高压低密度聚乙烯(LDPE)树脂产品中低分子质量聚合物含量的影响因素。通过分析高压聚乙烯聚合反应机理,结合实际生产条件,改进生产工艺,有效降低了LDPE树脂中低聚物含量。     

高透明薄膜用LDPE 2436H的开发

通过对低密度聚乙烯(LDPE)聚合机理和分子结构的分析,找出了影响薄膜光学性能的各种因素,从而确定了提高薄膜透明度的生产工艺和控制参数。LDPE薄膜用进口树脂和国产树脂最大的竞争在于所制薄膜的浊度,浊度决定了LDPE薄膜产品在市场上的地位。高透明薄膜专用树脂2436H所制薄膜的浊度为4.9,其机械性能也明显强于普通LDPE膜用树脂,达到了生产高透明膜的预期效果。     

工业流化床聚乙烯树脂性能模型的研究

本文首先分析了聚乙烯树脂熔融指数和密度变化的影响因素,建立了流化床动态过程中聚合物性能指标的递椎关系和工业流化床乙烯气相聚合过程产品质量的预测模型,利用乙烯气相（共）聚合过程中不同工艺条件下树脂的质量数据,对模型参数进行了优化,提出由于影响因素的相互关联,熔融指数和密度的控制应该联合进行;熔融指数和密度的计算值与测量值之间的平均误差分别为8.19%和0.13％。预测精度满足要求,模型可以应用于具体的工业生产过程。     

药用薄膜专用LDPE树脂产品介绍

中国石化上海石油化工股份有限公司(简称上海石化)现有二套低密度聚乙烯(LDPE)生产装置,LDPE生产总产量可达200 kt/a。两套LDPE装置工艺均为引进日本三菱油化株式会社的管式法工艺,可向市场稳定提供轻包装薄膜专用树脂(Q210,Q281,Q400)、重包装薄膜专用树脂(Z045)、     

高熔体指数LDPE热切粒工艺条件的初步探索

一、前言随着国民经济的发展,高压聚乙烯(LDPE)产品需求量日益增加,各种高熔体指数牌号的LDPE树脂(如塑料花料、油田脱蜡料等)亦已批量生产。对这些高熔体指数LDPE树脂产品不仅要从聚合过程上改变工艺条件,尤其要解决树脂切粒过程这一难关。本文主要介绍对高熔体指数LDPE热切粒工艺条件的探索和操作经验。     

国内快讯

广州石化推出聚丙烯新品广州石化化工二部1号聚丙烯装置日前成功生产出高流动性聚丙烯产品S980T。经分析检测,样品的熔融指数54.77 g/10min,色粒数小于5,质量品级为优级,各项性能指标均优于预期目标。目前已经进入稳定生产阶段。S980T是生产树脂中熔融指数最高     

陶氏推出全新AGILITY~(TM) EC 7030高性能LDPE

<正>陶氏化学公司近日宣布扩大其AGILITY?高性能低密度聚乙烯(LDPE)树脂产品组合。新的树脂解决方案可以帮助薄膜制造商在中低线速度下实现轻量化涂布,以应对亚太地区的包装难题。最新推出的AGILITY?EC 7030高性能LDPE树脂采用陶氏的新型管式聚合专利技术,可满足亚太地区从高压釜式工艺向管式工艺转换的需求。该新产品进一步丰富了AGILITY?产品组合,适用于不同速度的挤出机,可用于生产各类终端产品。AGILITY?高性能LDPE树脂系列产品的开发,旨在满足并超越传统高压釜式LDPE树脂的性能指标,并     

我国涂覆级树脂生产状况及发展前景

综述了涂覆级低密度聚乙烯(LDPE)和聚丙烯(PP)的生产工艺、工艺参数、产品性能指标、基础性能评价、加工性能及应用领域。针对生产实际情况,论述了涂覆级LDPE和PP树脂对复合袋剥离强度的影响。今后应加强开发双功能的过氧化物,在较高的温度下,以较高的收率得到高相对分子质量涂覆级LDPE。寻求较低的熔点和较好的密封性能,是涂覆级PP的研究方向。     

LD 100 BW电缆专用料的开发

通过研究200kt/a低密度聚乙烯装置的反应工艺条件与产品物性的对应关系．初步确定了开发电缆专用料LD 100 BW的生产工艺条件,并进行了工业化试生产、性能测试及应用试验。根据试验结果．对反应温度、聚合物浓度、转化率和添加剂注入系统等生产工艺条件进行了改进。改进后生产的LD 100 BW完全满足电缆行业标准,产品质量稳定。     

LDPE发泡专用树脂18F的开发

通过分析低密度聚乙烯(LDPE)发泡树脂物性指标,针对加工厂家的要求和装置的特点．设计出了LDPE发泡专用树脂18F,确定了18F的物性参数和生产工艺操作条件,并进行了试生产和产品的加工应用试验。试验证明,18F树脂发泡性能优异,发泡倍率可达40,冲击回弹率可达39％,且加工性能优良。生产的制品泡孔均匀、细致,能满足用户的使用要求。     

活性硅油对LDPE的改性作用的研究

本文研究活性硅油对ＬＤＰＥ的化学改性作用。红外光谱（ＩＲ）和熔体指数（ＭＩ）的测定结果表明，用过氧化物为引发剂，在熔融状态下，活性硅油分子可接枝到聚乙烯分子链上。经硅油接枝改性后的聚乙烯而环境应力开裂能力大大增强；树枝引发示性电压和工频击穿电压也得到明显提高。     

NA催化剂在高速BOPP薄膜专用树脂生产中的应用

介绍了国产NA催化剂应用于高速双向拉伸聚丙烯薄膜专用树脂F400-H生产的情况,并与进口催化剂进行了对比。结果表明,用NA催化剂生产的F400-H,催化剂平均活性达22．7kg／g,产品等规指数达97．4％,均优于进口催化剂。装置运行稳定,产品性能优良,薄膜拉伸速度达到380m／mim以上,且不易破断。     

Mechanical strengths of molten and solidified LLDPE/LDPE blends and wood/LDPE composites under tensile deformation

The mechanical strengths of neat low‐density polyethylene (LDPE), a blend of LDPE with linear low‐density polyethylene (LLDPE), and a composite of LDPE with wood flour (wood/LDPE) were investigated in molten and solidified states under tensile deformation. The results are discussed in terms of the effects of LLDPE and wood contents, roller speed, and volumetric flow rate. In LLDPE/LDPE blends, incorporating LLDPE from 0 to 30 wt% into LDPE caused a slight increase in drawdown force, a larger fluctuation in drawdown force, and a reduction of maximum roller speed to failure. The mechanical properties of the solidified LLDPE/LDPE corresponded to those of the molten LLDPE/LDPE with regard to the effect of LLDPE content. For wood/LDPE composites, increasing the wood flour content in molten LDPE caused considerable reductions in drawdown time and maximum roller speed to failure. The drawdown force increased with increasing wood flour up to 10 wt% before it decreased at the wood loading of 20 wt%. A number of voids and pores on the extrudate surfaces became obvious for the composites with 20 wt% of wood content. Increasing wood content enhanced the tensile modulus for the solidified LDPE but decreased its tensile strength. Unlike those of LLDPE/LDPE blends, the changes in tensile modulus and strength of solidified wood/LDPE composites with wood content did not correspond to those of the molten composites. In all cases, the drawdown force increased with increasing roller speed. The effect of volumetric flow rate from the extruder on the mechanical strengths of the solidified blends was more pronounced than on those of the molten ones. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Measurement of solubility and diffusion coefficients of ethylene in solid and molten low-density polyethylene with different melt indices

The diffusion behavior of ethylene in polyethylene is of great importance for the polymerization and degassing of polyethylene (PE) industry. Based on the gravimetric sorption and desorption measurement approach, an intelligent gravimetric analyzer is applied to obtain the solubility and diffusion coefficients of ethylene in solid low-density PE (LDPE) with different melt indices at 30°C to 70°C, 0 to 4 atm and in molten LDPE at 160°C to 230°C, 0 to 4 atm, respectively. Results indicate that both the solubility and diffusion coefficients of ethylene in solid LDPE are smaller than those in molten LDPE, while the dissolution enthalpy and diffusion activation energy of ethylene in solid LDPE are higher. In addition, one- and two-dimensional diffusion models are built and the effects of particle size, polymer properties, and operation conditions are systematically investigated on the diffusion behaviors of ethylene in solid and molten LDPE.     

Rheological and mechanical properties of composites made from wood flour and recycled LDPE/HDPE blend

The effect of compounding method is studied with respect to the rheological behavior and mechanical properties of composites made of wood flour and a blend of two main components of plastics waste in municipal solid waste, low-density polyethylene (LDPE) and high-density polyethylene (HDPE). The effects of recycling process on the rheological behavior of LDPE and HDPE blends were investigated. Initially, samples of virgin LDPE and HDPE were thermo-mechanically degraded twice under controlled conditions in an extruder. The recycled materials and wood flour were then compounded by two different mixing methods: simultaneous mixing of all components and pre-mixing, including the blending of polymers in molten state, grinding and subsequent compounding with wood flour. The rheological and mechanical properties of the LDPE/HDPE blend and resultant composites were determined. The results showed that recycling increased the complex viscosity of the LDPE/HDPE blend and it exhibited miscible behavior in a molten state. Rheological testing indicated that the complex viscosity and storage modulus of the composites made by pre-mixing method were higher than that made by the simultaneous method. The results also showed that melt pre-mixing of the polymeric matrix (recycled LDPE and HDPE) improved the mechanical properties of the wood–plastic composites.     

管式法挤出涂层专用LDPE的性能及质量改进

针对管式工艺生产的挤出涂层专用低密度聚乙烯(LDPE)产品存在涂层与基材的黏结强度低、淋膜缩幅大等问题,通过与同类釜式产品的性能和结构的对比研究发现,管式产品的分子支化程度过低是造成其性能不佳的主要原因。分析了影响产品长链支化程度的工艺因素,并提出了增加产品长支链含量的方法。初步试生产表明:适当提高反应温度、降低反应压力并改变分子量调节剂的注入速度,可以有效地改善挤出涂层产品的性能。     

高压低密度聚乙烯粘壁原因分析及解决措施

简述了高压低密度聚乙烯(LDPE)管式反应器除去粘壁的重要性,并简要介绍了生产LDPE装置的工艺流程,分析了高压管式反应器可能产生物料粘壁的原因,并提出了预防措施和具体的解决方法,进而保证了装置生产能力满负荷运行和保证了产品质量指标。