旋转模塑用聚氯乙烯增塑糊的研究

一般来讲，影响旋转模塑用PVC增塑糊性能有五个因素，即PVC增塑糊的流变性能、糊粘度稳定性、脱气性能、凝胶化性能和塑化性能。作者通过对影响PVC增塑糊性能的这些因素进行深入研究，对确定PVC增塑糊所用原料种类和数量提供有益的参考。     

环保聚氯乙烯增塑糊凝胶性能的研究

采用转矩流变仪和旋转黏度计研究了PVC树脂种类、增塑剂种类、掺混树脂加入量对环保PVC增塑糊凝胶性能的影响规律。结果表明,PVC糊树脂聚合度越大,增塑糊的凝胶化时间越长;颗粒呈规则圆状树脂配制的增塑糊,其凝胶时间相对较长;颗粒呈扁片状的树脂配制的增塑糊,其凝胶时间相对较短。增塑剂与PVC糊树脂相容性越差,增塑糊的凝胶时间越长。随掺混树脂添加量的增多,凝胶时间逐渐延长,当其加入量为40 份（质量份,下同）时,凝胶时间从空白时的18 min延长至28 min。     

PVC糊粘度影响因素的讨论

研究了PVC糊中部分主要组分对其糊粘度的影响，重点探讨了糊状PVC树脂种类、增塑剂的种类及用量、降粘剂的种类及用量等几大主要因素对PVC糊粘度的影响。实验结果表明，由于不同生产工艺使PVC糊树脂的初级粒子的粒径、粒子形态及粒子的分布形式不同，造成其成糊粘度及稳定性的差异。增塑剂的挥发性及溶剂化能力的差异会影响糊的粘度及稳定性。脂肪族烃类和可增塑类降粘剂的降粘机理的不同，会产生降粘效果的差异。     

旋转模塑用聚氯乙烯增塑糊的研究

对影响ＰＶＣ增塑糊性能的五个因素：ＰＶＣ增塑糊的流变性能、糊粘度稳定性、脱气性能、凝胶化性能和塑化性能进行较为深入的研究；为确定ＰＶＣ增塑糊所用主要原料的种类和用量提供了有益的参考。     

旋转模塑用聚氯乙烯增塑糊粘度稳定性研究

PVC增塑糊粘度稳定性是影响糊制品加工工艺的重要因素。本文利用NDJ-1型旋转粘度计,通过测定糊粘度随时间的变化,对影响PVC增塑糊粘度稳定性的各种因素进行了较为详细的研究。     

聚氯乙烯糊用掺混树脂对增塑糊及制品性能的影响

本文通过实验研究了掺混树脂对ＰＶＣ增塑糊的流变性能，凝胶化性能，糊粘度陈化稳定性及对增塑糊制品的力学性能、热性能、物理性能和发泡性能的影响，并分析了其影响作用的机理。     

轿车扶手表皮材料─旋转模塑用聚氯乙烯增塑糊粘度稳定性研究

PVC增塑糊粘度稳定性是指粘度随时间的变化，是影响糊制品加工工艺的重要因素。本文利用NDJ－1型旋转粘度计，通过测定糊粘度随时间的变化．对影响PVC增塑糊粘度稳定性的各种因素进行了较为详细的研究。     

PVC糊凝胶化性能的测定

采用布拉本德塑化仪和旋转粘度计,测定了PE709、A-21和PSM-31三种PVC糊的凝胶化性能,探讨了增塑剂用量、混合增塑剂对凝胶化性能的影响,比较了这两种测试方法的特点。结果表明,PE709具有低温,快速凝胶化特点,A-21具有较高的凝胶化温度和较慢的凝胶化速度。随增塑剂用量增加,达到一定转矩或一定粘度所需温度增加或时间延长。在增塑剂DOP中采用BBP增塑剂可使达到一定粘度所需时间缩短。由本工作得出结论,布拉本德塑化仪可全面反映凝胶化特征,但精度和重复性较差,旋转粘度计测量的粘度范围较窄,但测量精度和重复性较好。     

增塑剂对旋转模塑用PVC增塑糊性能的影响

作者对增塑剂种类及用量与旋转模塑用PVC增塑糊性能的关系进行了较为深入的研究,从而为旋转模塑用PVC增塑糊中增塑剂种类及用量的确定提供了有益的参考。     

基本粒度分布和PVC增塑糊粘度

1.前言 本文叙述糊状PVC加工中基本粒度分布和增塑糊粘度的关系。 一般糊用PVC含有密集的,平均粒度1μm左右以及单峰或双峰分布的,球形基本颗粒,这种PVC与某些其他成份分散在增塑剂中。形成增塑糊,就可用于加工增塑糊的流变性能必须严格控制在一定范围内。其中最重要的是该增塑糊的粘度。 增塑糊中的增塑剂可用图解表示,分为三个部分。即第一部分为颗粒表面润湿的一定厚度的固定层。第二部分为填充颗粒之间孔隙。第三部分为自由增塑剂,起加速增塑糊的流动作用。     

Optimization of plastisol processes by dynamic mechanical analysis

Dynamic mechanical analysis (DMA) can be a particularly useful tool for studying PVC plastisol manufacturing processes. DMA temperature sweeps are uniquely able to characterize plastisol gelation and fusion behavior under low shear stress conditions that are similar to conditions found in many commercial plastisol processing operations. Dynamic mechanical analysis is also well‐suited for studying plastisol melt viscosities at low shear rates such as might be encountered in a flexible PVC foaming process or rotomolding process. Likewise, DMA rate sweeps or strain sweeps can give insights into self‐association and flow properties in a plastisol which ordinary viscometers cannot provide. J. VINYL ADDIT. TECHNOL., 13:151–154, 2007. © 2007 Society of Plastics Engineers     

Changes in rheological properties of polyvinyl chloride plastisols with storage time

In this study, the changes in the rheological curves of polyvinyl chloride (PVC) plastisols with increasing storage time and the factors affecting these changes were studied. The results show that with increasing storage time, all the “viscosity–temperature” and “viscosity–time” rheological curves of PVC plastisols exhibit nonnormal distribution change trends, that is, the viscosity first decreases, and then changes from slow increasing to rapid increasing, forming a shoulder peak, reaches to the maximum value and gradually decreases. With increasing storage time, the complex viscosities of PVC plastisols increased generally in the first, the second, and the fourth stages, and the gelation process shortened in the third stage. The first and second stages of the viscosity changes reflect the “time–temperature” equivalence principle of PVC plastisol in suspension stage. However, the maximum viscosity of PVC plastisol corresponding to temperature Tη_max does not change with increasing storage time.     

Meaningful evaluation of plastisol gelation and fusion temperatures by dynamic mechanical analysis

In most PVC plastisol processing operations, gelation and fusion characteristics of the plastisol are critically important. For example, in chemically foamed plastisols, plastisol fusion temperature and blowing agent decomposition temperature must be carefully coordinated. In rotomolded parts, rates of gelation may determine the quality of the finished parts. For plastisol products made by any process, the final fusion temperature determines the processing temperatures required to give the finished product acceptable mechanical properties. For a variety of reasons, the methods commonly used to characterize plastisol gelation and fusion (hot bar test, resin in plasticizer clear point, torque rheometer measurements, etc.) provide comparisons between plastisols but do not provide temperatures that are easily related to actual industrial processes. With dynamic mechanical analysis (DMA), one can characterize, under low shear conditions, the temperatures at which gelation begins, gelation ends, and complete fusion occurs. Additionally, it is possible to record plastisol viscosities (and other dynamic mechanical properties) over the processing temperature range. We used a multiple linear regression program to analyze the DMA data for plastisols heated from 30 to 210°C and containing either 70, 80 or 90 phr of Jayflex dihexyl phthalate (DHP) or Jaylflex di-isodecyl phthalate (DIDP). Further, we determined the plasticizer phr dependence and the reproducibility of gel and fusion temperatures given by data analyzed in this manner. Finally, for comparison, we analyzed the reproducibility of initial and final plastisol gel temperatures and fusion temperatures, which were determined by visually analyzing the DMA data for plastisols containing 70, 80, and 90 phr of Jyflex plasticizers DHP, Jayflex 77, diisononyl phthalate (DINP), and DIDP. Precise characterization of plastisol gelation and fusion behavior will, undoubtedly, facilitate substitution of plastisol ingredients as is often required by those who manufacture and process plastisols.     

Processability of PVC plastisols containing a polyhydroxybutyrate‐polyhydroxyvalerate copolymer

Plastisols based on polyvinyl chloride (PVC) can be processed by different techniques; their processability markedly depends on their flow properties and gelation/fusion processes. Classically, PVC has been the only polymer present in plastisol formulations. The present work explored the possibility of adding polyhydroxyalkanoates (PHAs), a type of biopolymer that, according to previous work, exhibits a good miscibility with PVC processed by other techniques (internal mixer and compression molding). The influence of PHA particles on flow properties, gelation‐fusion processes, tensile strength, hardness, and processability by rotomolding was evaluated. Although the biopolymer markedly increased the viscosity of PVC plastisols and caused a decrease in tensile strength in processed specimens, formulations including 20% by weight of biopolymer presented a good thickness distribution in rotomolded items, an elongation at break of around 300%, and an ultimate tensile strength of around 6–7 MPa. J. VINYL ADDIT. TECHNOL.,, 2012. © 2012 Society of Plastics Engineers     

Viscoelastic measurements of PVC plastisol during gelation and fusion

This work is concerned with the change of viscoelastic properties of poly(vinyl chloride) (PVC) plastisol during heating. The system changes from a suspension of solid particles in a liquid medium to a swollen gel and further to a fused state as the temperature is raised. The Rheometrics mechanical spectrometer was used in the oscillatory mode at 0.1 Hz. The temperature of the sample was raised in a controlled manner to 195°C. During gelation, the viscosity increased rapidly about three decades. There was a similar increase of the elastic modulus. After reaching a maximum, both viscosity and elastic modulus decreased rapidly with the progress of fusion. The viscoelastic properties depended somewhat on the heating rate. At 170-195°C, it took a few minutes for the moduli to reach steady values. Continued heating, for several minutes at 195°C, did not change the moduli any further. The temperature range of the decomposition of a blowing agent in the plastisol foam formulation was determined. Over this temperature range, the viscoelastic properties change very rapidly. Quantitative estimates were made for the decrease of moduli during this period.     

Feasibility study of water as thinner for polyvinyl chloride plastisol

In the traditional formula of polyvinyl chloride (PVC) gloves, the diluent of PVC plastisol is usually organic solvent, which causes serious environmental pollution during the molding process. The aim of this study was to develop a low viscosity PVC plastisol emulsion (PDE) using water as a thinner by blending PVC emulsion (PVCE) with diisononyl phthalate (DINP) emulsion. DINP emulsion (DINPE) was prepared by a compound emulsifier of polyoxyethylene octyl phenol ether-10 and sorbitan monooleate. The effects of compound emulsifier concentration on the stability and microstructure of DINPE were investigated. The results showed that the optimal compound emulsifier concentration of DINPE was 10 wt%. In addition, the PDE obtained by blending exhibited a relatively uniform unimodal droplet size distribution. The steady state data revealed that the emulsions were shear-thinning pseudoplastic liquid. The effect of solid content and temperature on the apparent viscosity of PDE were also evaluated. The mechanical spectra obtained suggested the presence of weak gel structure in the PDE. The mechanical test results showed that the tensile strength and elongation at break of PVC film obtained by PDE were 12.62 MPa and 310.31%, respectively. This study demonstrated that water was effective in reducing the viscosity of PVC plastisol, which would promote the application of water thinner in glove production.     

Effect of plasticizer type on gelation and fusion of PVC plastisol,dialkyl phthalate series

Different grades of PVC resins and a variety of plasticizers are used to adjust processability and properties of plastisol. The plastisol, which is a dispersion of fine particles of PVC in plasticizer, is coated on a substrate and heated in an oven to gel and fuse. In the gelation stage the resin particles become swollen with plasticizer and then, in the fusion stage the entire system fuses to become one homogeneous phase. The finished products are flexible PVC such as coated fabrics and surgical globes. Different plasticizers, because of the difference in solvent power, affect the process of gelation and fusion, and hence, processability. This paper examines such an effect systematically by employing a homologous series of plasticizers, dialkyl phthalates. The progress of gelation and fusion are followed by the measurements of dynamic moduli and by the observation with a scanning electron microscope. As it may be expected, the shorter the alkyl chain, the higher the solvent power of the plasticizer.     

Optimizing performance of benzoate and phthalate blends for vinyl applications

To achieve required performance, blends of plasticizers are commonly used in flexible vinyl applications. Typically, when fast fusion is required, high solvating phthalates have been utilized in plasticizer blends. Benzoate esters are high solvators and can also be used in these blends. However, even though benzoate plasticizers offer additional performance benefits that can complement general‐purpose phthalate performance, most of the literature does not include the use of benzoate plasticizers in blends with phthalates. The purpose of this article is to demonstrate the performance benefits of blending benzoate and phthalate plasticizers. The approach selected to accomplish this task was to develop performance data by utilizing a mixture design approach with DOE (design of experiments) software. A resilient flooring plastisol formulation was selected as the model. The following properties were obtained: degassing, low and high shear viscosity, viscosity stability of the plastisol, gel and fusion characteristics, tensile strength vs. temperature, vinyl heat stability, stain resistance, volatility, and UV stability. The data indicate how to utilize the advantage of benzoates as “process aids” to speed production rates and improve product quality. J. VINYL. ADDIT. TECHNOL. 11:150–154, 2005. © 2005 Society of Plastics Engineers