国产聚乙烯醇助分散剂对悬浮法聚氯乙烯树脂颗粒特性的影响

在聚乙烯醇／羟丙基甲基纤维素复合主分散体系基础上加入聚乙烯醇助分散剂。对比研究了国内外同类型聚乙烯醇对分散体系界面张力、保胶能力和聚氯乙烯树脂颗粒形态的影响。结果发现：随着聚乙烯醇助分散剂含量增加,分散剂水溶液一三氯乙烯界面张力和保胶能力降低,聚氯乙烯树脂平均粒径和增塑剂吸收量增加,初级粒子聚集程度降低。     

分散剂和非离子型表面活性剂对悬浮聚氯乙烯树脂颗粒特性的影响

研究了聚乙烯醇(PVA)分散剂和非离子型表面活性剂对悬浮聚氯乙烯(PVC)树脂颗粒特性的影响。结果表明随着PVA醇解度的增加，PVC树脂的颗粒规整性和表现密度增加，孔隙率和吸油率降低；随着非离子型表面活性剂添加量的增加，PVC树脂的平均粒径和吸油率增大。从PVA和表面活性剂在水一油两相分配出发，讨论了PVA醇解度和添加非离子型表面活性剂对PVC树脂的颗粒特性影响机理。     

悬浮态乳液聚合条件对聚氯乙烯树脂颗粒特性的影响

Suspended emulsion polymerization of vinyl chloride was carried out in a 5 L autoclave. The influence of agitation, polymerization conversion, dispersant and surfactant on the average particle size (PS) and particle size distribution (PSD), particle morphology and porosity of polyvinyl chloride (PVC) resin was investigated. It showed that the agitator had great influence on the smooth operation of polymerization, PS and PSD. The PS increased and PSD became narrow as polymerization conversion became high. The porosity decreased with the increase of conversion. A convenient choice of additives, both dispersants and non-ionic surfactants, allows one to adjust PS and PSD. The PS decreased with the addition of polyvinyl alcohol or hydroxypropyl methylcellulose dispersants,and increased with the addition of Span surfactants. The addition of dispersants or surfactants also affected the morphology and porosity of resin, and PVC resin with looser agglomeration and homogeneous distribution of primary particles was prepared.     

国产助分散剂油溶性聚乙烯醇HNB02

比较了国产助分散剂油溶性聚乙烯醇ＨＮＢ０２与进口助分散剂ＬＬ－０２在３０ｍ＾３釜上生产聚氯乙烯时的使用效果,对比了使用这两种助分散剂时生产树脂的质量、成本与粘釜状况。     

悬浮法聚氯乙烯树脂颗粒形态的影响因素

重点分析了影响悬浮法聚氯乙烯树脂颗粒形态的主要因素——分散剂和搅拌，还分析了转化率、聚合温度、水油比、引发剂、pH值等其他因素的影响，提出了控制优良的树脂质量和形态的工艺条件。     

悬浮聚合法制备聚氯乙烯树脂

采用悬浮聚合法制备堆积密度大,加工性能好的聚氯乙烯树脂,把氯乙烯单体或氯乙烯为主要成分的聚合单体、水溶剂、悬 浮分散剂聚合引发剂作为悬浮聚合成分的氯乙烯悬浮滞方法。该悬浮分散剂最少有一种成分是用氧化铝水合物处理氧化钛的微粒子表面,再对其表面进行有机物包覆处理,是这一方法特征。     

采用复合分散剂制备高表观密度聚氯乙烯树脂

介绍了高醇解度、高粘度聚乙烯醇 6 35与分散能力较强的其它分散剂按一定配比复合后的使用情况 ,结果表明 :采用复合分散剂 ,可在保持PVC树脂具有适当孔隙率的前提下 ,提高其表观密度 ;采用KH2 0 /6 0SH5 0复合分散剂在 10L釜中制得的PVC树脂表观密度约为 0 .4 6g/mL ;采用 6 35 /B72或 6 35 /F5 0复合分散剂制得PVC树脂的表观密度可比采用通用分散体系提高 10 %～ 15 % ,且水油比减少 ,增塑剂吸收量提高。分析了影响树脂表观密度和颗粒形态的主要因素     

氯乙烯悬浮聚合中大颗粒的预防

1 分散剂对聚合物质量的影响 1.1 从PVC成粒过程看大颗粒的形成原因 PVC的成粒过程是在VCM—水相中进行的。首先在搅拌的作用下,液态VCM单体分散成液滴状,悬浮在水介质中,借助搅拌剪切力作用破裂为小液滴,分散在水相中,小液滴亦可聚并成大液滴,到一定程度时分散和聚并构成动态平衡,平均滴径趋向定值(但有一个分布),分散剂有降低表面张力和保护膜     

影响聚氯乙烯树脂颗粒形态的因素

介绍了搅拌、分散剂、转化率、聚合温度水油比对聚氯乙烯树脂颗粒形态的影响,提出了保证合适的树脂质量及形态的控制工艺条件和参数。     

Influences of some polymerization conditions on particle properties of suspension poly(vinyl chloride) resin

Effects of polymerization temperature, conversions, and nonionic surfactant on the particle properties of suspension poly(vinyl chloride) (PVC) resins were investigated. It was shown that polymerization temperature has no significant influences on the mean particle size of PVC resin, and that the cold plasticiser absorption (CPA) of resin decreases linearly with the increase of polymerization temperature. Agglomeration of VCM droplets finishes before 20% conversion, and the mean particle size keeps almost constant at later stages of the polymerization process, but the CPA continues decreasing with the increase of conversion. Scanning Electron Microscopy (SEM) micrographs show that the degree of agglomeration of primary particles increases with polymerization temperature and conversion. Addition of nonionic surfactant to the VCM suspension system, as a secondary suspending agent, has a great influence on the particle properties of PVC resin. The particle size and CPA increase as the concentration of nonionic surfactant increases. The nonionic surfactant with a greater HLB value is more effective in raising the mean particle size, but is less effective in raising the CPA. It is considered that the added nonionic surfactant would be absorbed faster on the VCM/water interface than the poly(vinyl alcohol) (PVA), which was used as the primary suspending agent. Because the colloid protection ability of the nonionic surfactant is less than that of PVA, droplets become less resistant to coalescence, and the mean particle size of the final PVC resin increases consequently. The increase of porosity is caused by the combined effects of increased coalescence of VCM droplets and the nonionic surfactant's steric effect inside the droplets. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1544–1552, 2002     

国产水分散型助分散剂在氯乙烯聚合中的应用

通过对国内外各种助分散剂的应用对比,针对PVC生产中存在的问题,在油溶性PVA生产技术基础上,添加VAC共聚单体,研制开发出一种水分散型助分散剂,其各项性能达到国外同类产品水平,现已工业化生产,应用于国内部分PVC厂家。     

用国产分散剂PVA生产聚氯乙烯树脂

以国产分散剂ＰＶＡ（２０８０、ＷＨ－６）代替进口分散剂ＰＶＡ（ＫＨ－１０、Ｌ－９或ＡＬＣＯＴＥＸ７２．５）,在引进的７０．５ｍ＾３聚合釜中生产聚氯乙烯树脂。分散体系始终正常、稳定,生产的树脂质量同使用进口ＰＶＡ相比无任何差异,在粘釜问题上未见异常,经济效益较为显著。     

国产分散剂在悬浮聚合PVC中的应用

介绍了国产分散剂替代现用进口分散剂在悬浮聚合中的应用。通过试验对比,考察了国产分散剂的使用效果以及对聚氯乙烯树脂各项指标的影响。通过优化分散剂体系,提高了PVC树脂的质量,降低了生产成本。     

氯乙烯悬浮聚合原辅材料质量对聚合工艺和产品质量的影响

介绍了氯乙烯悬浮聚合原辅材料质量要求及其对聚合工艺和产品质量的影响。     

氯乙烯悬浮聚合热进料工艺的实现

一般的PVC生产工艺,均采用冷水加料,再通过夹套和内冷挡板通入蒸气或热水升温,而后开始聚合反应,在目前我国DCS控制技术成熟的情况下,我们也可以采用热无离子水和冷的VCM同时加入釜内,当加料结束时釜内温度即为反应温度,采用这种热水加料工艺可以缩短单釜间歇反应周期,提高单釜生产效率.     

VCM悬浮聚合分散剂体系研究(PVC-SG3型树脂的中试)

悬浮法VCM聚合所用分散剂品种较多，按其应用主要分为两大类，即：聚乙烯醇类和纤维素醚类。我们通过试验，在聚合过程中采用单一的PVA三元复合分散剂体系，所试制的PVC树脂各项常规指标和塑化性能均优于HPMC分散体系的树脂。     

两种制备疏松PVC树脂的新型聚合方法

介绍了制备疏松PVC树脂的两种新聚合方法——以正丁烷为反应介质分散聚合和悬浮态乳液聚合，并对树脂颗粒的特性进行了简述。结果表明：以正丁烷为反应介质的非均相VC分散聚合所得树脂的粒径和颗粒形态与聚合体系VC／But比例和转化率等有关，由于存在向But的链转移，PVC分子质量小于相同聚合温度下生产的悬浮PVC树脂。悬浮态乳液聚合所得树脂粒径分布和颗粒形态与水油比、转化率和添加剂品种有关。     

氯乙烯悬浮聚合复合引发剂体系的中试研究

提出了生产3种牌号PVC树脂的复合引发剂配方。中试结果表明:采用悬浮法生产S-700、S-1000和S-1300 PVC树脂时宜分别采用Tx-36和Tx-23、EHP和Tx-99、Tx-99和Tx-23复合过氧化物引发剂体系,聚合时间可控制在3.2~3.8 h,反应过程平稳,反应速率快,生产的PVC树脂质量优良。