丙烯酸酯类加工助剂ACR影响PVC加工性能的探讨

本文研究了丙烯酸酯类PVC加工助剂ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂ACR对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

ACR加工助剂对PVC加工性能的影响

采用转矩流变仪分析了流变性能曲线和挤出曲线,探讨了ACR加工助剂在PVC加工过程中所产生的影响。实验表明:ACR加工助剂能够促进PVC体系的塑化,提高熔体强度及均匀性,对PVC的力学性能没有明显的不良影响。     

邹城投产ACR加工助剂

日前,年产1000t的ACR系列PVC加工助剂装置,在山东省邹城市艾立特化工有限公司投产,填补了该产品在鲁西南地区的生产空白。ACR加工助剂主要应用在PVC加工过程中,促进PVC塑化,改善PVC熔体流动性,防止熔体破裂。邹城投产ACR加工助剂     

丙烯酸醋类加工助剂acr影响pvc加工性能的探讨

本文研究了丙烯酸酯类PVC加工助剂ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂ACR对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

丙烯酸酯类加工助剂ACR影响PVC加工性能的探讨

本文研究了丙烯酸酯类PVC加工助剂ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂ACR对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

PVC用ACR加工助剂的作用

简要介绍了ACR加工助剂发展历史及其改进PVC加工性能的作用，包括对PVC的离模膨胀、熔体破裂、熔体粘度和融化的影响。并讨论了不同生产商的ACR加工助剂及其在PVC中的不同用途。     

ACR对PVC加工性能的影响

详细研究了丙烯酸酯类PVC加工助剂———ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

PVC用加工助剂及冲击改性剂

<正>1加工改性助剂1.1加工改性助剂的作用原理聚氯乙烯(PVC)熔体延展性差,易导致熔体破碎,PVC熔体松弛慢,易导致制品表面粗糙、无光泽及鲨鱼皮等。因此,PVC加工时往往需要加入加工助剂,以改善其熔体缺陷。加工助剂为可以改善树脂加工性能的助剂,其主要作用方式有三种:促进树脂熔融、改善熔体流变性能及赋予润滑功能。①促进树脂熔融:PVC树脂在加热的状态下,在一定的剪切力作用下熔化     

丙烯酸加工助剂对聚氯乙烯拉伸流动的影响

采用毛细管粘度计测拉伸粘度的方法,研究丙烯酸加工助剂的类型、用量及测定温度对PVC拉伸流动的影响。实验证明,PVC熔体的拉伸流动对拉伸速率的依赖性近似于Troton行为;促进凝胶化型的丙烯酸加工助剂使PVC的拉伸粘度显著提高,且随助剂的用量的增加而增加,但随温度的升高而降低;润滑型丙烯酸加工助剂则使PVC的拉伸粘度有升有降。     

ACR对PVC加工性能的影响

详细研究了丙烯酸酯类PVC加工助剂——ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明，随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高，其塑化速度增大，但熔体强度降低，在组成相同的情况下，特性黏度越大，塑化越慢，熔体强度越大；丙烯酸酯类加工助剂对PVC制品的拉伸强度和维卡软化点无明显影响，高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

In-depth rheological study of acrylic processing aids in rigid polyvinyl chloride applications

Acrylic processing aids are used widely in rigid polyvinyl chloride (PVC) applications. Key functions of processing aids in terms of processing and performance are discussed in the paper. Effect of molecular weight of acrylic processing aids on their functions are studied. Additionally, effect of processing conditions, such as temperature and shear on fusion characteristics of PVC formulations are investigated. Shear rate in the processing was varied by means of rotor speed in torque rheometer. Processing aids of comprehensive molecular weight range are evaluated in the study. It was observed that relatively lower molecular weight processing aids have different response to change in shear and temperature than higher molecular weight processing aids. Depending upon fusion conditions PVC formulations can yield either a single or double fusion peak. Generally, it was considered that ultra-high molecular weight processing aids yield a double fusion peak, however, it was demonstrated in the studies that it is not true. Fusion conditions, temperature, and shear are the main driving forces of fusion dynamics, resulting in either a single or double fusion peak. Relatively low molecular weight acrylic processing aids can also yield double fusion peak. Melt viscosity and shear thinning properties are also examined. Relatively lower molecular weight processing aids showed higher shear thinning behavior. Effect of temperature and shear on degree of fusion was studied. It was shown that optimum processing parameters can increase the degree of fusion by ~10%.     

Understanding the functions of acrylic processing aids in rigid PVC injection molding

Poly(vinyl chloride) (PVC) compound use is growing in specialty injection molding applications such as appliances, business equipment, and electrical enclosures. A key factor in determining the appearance and physical properties of the molded parts is the processability of the PVC compounds, which can be improved through the use of acrylic processing aids. Processing aids promote PVC fusion, modify the melt rheology, and/or provide lubrication. Some processing aid products are designed to serve one of these functions while others provide a combination of functions. Each of these functions and its major benefits in rigid PVC injection molding are described. Some guidelines for selecting appropriate processing aid products for applications are provided.     

New ultra high molecular weight acrylic processing aids for rigid PVC foaming

Foaming of rigid polyvinyl chloride (PVC) is studied as a function of high molecular weight acrylic processing aids. The industrial process to evaluate quality of foam is discussed in detail. The role of acrylic processing aids to improve melt strength and hence foaming of PVC is explained. It is demonstrated that increase in molecular weight of acrylic processing aids increases its effectiveness. It is found that ultra-high molecular weight processing aids is 25%–30% more efficient than relatively lower, but still high, molecular weight acrylic processing aids. The higher molecular weight processing aids provided comparable foaming performance at lower loading levels. Foaming reduced the density of PVC compounds to 0.32–0.34 g/cm³. More than 1000% expansion is achieved in the melt extrusion process using a chemical blowing agent. Fusion characteristics are also studied. Fusion times for initial fusion peaks are in the range of 42–44 s while the fusion times of the second fusion peaks are in the range of 74–94 s. The higher molecular weight processing aids maintained fusion characteristics of PVC compounds, warranting no significant changes in commercial process.     

Effects of acrylic‐based processing aids on processibility,rheology, thermal and structural stability,and mechanical properties of PVC/wood–sawdust composites

Methyl methacrylate and ethylacrylate (MMA‐co‐EA) and methyl methacrylate and butylacrylate (MMA‐co‐BA) copolymeric processing aids were introduced into poly(vinyl chloride) (PVC)/33.3 wt % wood–sawdust composites containing 0.6 and 2.4 phr of calcium stearate lubricant. The properties of the composites were monitored in terms of processibility, rheology, thermal and structural stability, and mechanical properties. It was found that the mixing torque, wall shear stress, and extrudate swell ratio increased with increasing processing aid content because of increased PVC entanglement. MMA‐co‐BA (PA20) was found to be more effective than MMA‐co‐EA (K120 and K130), this being associated with the flexibility of the processing aids, and the dipole–dipole interactions between sawdust particles and polymeric processing aids. The sharkskin characteristic of the composite extrudate at high extrusion rate was moderated by the presence of processing aids. Adding the acrylic‐based processing aids and lubricant into PVC/sawdust composites improved the thermal and structural stability of the composites, which were evidenced by an increase in glass transition and decomposition temperatures and a decrease in polyene sequences, respectively. The changes in the mechanical properties of the composites involved a composite homogeneity, which was varied by degree of entanglement and the presence of wood sawdust, and un‐reacted processing aids left in the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 782–790, 2004     

加工助剂对PVC木塑复合材料性能的影响

研究了4种新型加工助剂对聚氯乙烯(PVC)木塑复合材料的加工特性和物理力学性能的影响,并利用扫描电子显微镜(SEM)研究复合材料的冲击断面。结果表明,以不饱和芳香族碳氢化合物、脂肪烃树脂为主要组分的加工助剂,能够提高木粉在PVC基体中的分散性,改善木粉与PVC的相容性,从而明显提高PVC木塑材料的力学性能和加工性能;以钙皂和饱和脂肪酸酰胺混合物、脂肪醇和脂肪酸酯的混合物为主要组分的加工助剂,对木粉的分散性和复合材料的加工性能有一定的改善,但其用量较大时对复合材料的力学性能有不利影响。     

Effect of acrylic processing aids on PVC die swell

The die swell behavior of PVC melts is a manifestation of melt elasticity and is of considerable commercial as well as fundamental importance. This behavior is a critical issue in extrusion blow molding application where die swell (i.e. parison thickness) needs to be controlled. Advantageously, the addition of high molecular weight acrylic processing aids to PVC provides better die swell control, thus, improving dramatically the processability of PVC. Hence, knowledge of molecular weight variables of such acrylic processing aids is important from both the commercial and rheological point of view. Various acrylic processing aids were prepared by polymerization designed to provide systematic variation of molecular parameters. Molecular weight distribution of the polymers was characterized by GPC, and their die swell behavior in a typical PVC blow molding formulation was determined at 200°C over various range of residence times using different L/D capillary dies. The results are presented showing effects of specific molecular variables.     

Processing aids for poly(vinyl chloride)

Processing aids are an important class of additives for poly(vinyl chloride) (PVC). At relatively low concentration, processing aids enable the melt processing of rigid PVC and enlarge its processing windows. Discussed in this presentation are some major functions of processing aids, such as promoting PVC fusion, modifying PVC's melt rheology, and lubricating to prevent adherence of PVC melt to the processing equipment. Some examples are given to show the effects of processing aids on PVC die swell, melt fracture, melt viscosity, and PVC fusion. Commercial sources of various processing aids and typical PVC formulations for various applications are also discussed.     

An investigation of acrylic processing aids for low molecular weight PVC

Acrylic processing aids have long been used in rigid PVC to increase fusion, decrease jetting and blushing down in blow molding, decrease parison draw down in blow molding, improve the rolling bank in calendering, improve thermoforming, and improve cell structure in foam extrusion. It has generally been thought that the specific viscosity (Nsp/c) of process aids were limited to a fairly limited narrow range. Recently, significantly higher molecular weight process aids have been developed and commercialized. Very little work though has been done with low molecular weight process aids as these products were assumed to be ineffective when compared to the commonly used products. This paper will investigate currently available products and some experimental products well above and below the Nsp/c of currently available products. The major area of investigation will be in very low to low molecular weight PVC resins and will deal with the applicability of these products in injection molding.     

CPE、ACR等加工助剂对PVC—U流变性能的影响

研究了CPE、ACR等加工助剂及填料对PVC—U流变性能的影响。结果表明：CPE和ACR都能促进PVC的塑化,但作为冲击改性剂的CPE所起的塑化作用较ACR要小,硬脂酸的加入延长了PVC的塑化时间,在本体系中起到了外润滑剂的作用,填料的加入延缓了共混体系的塑化。     

Selecting the proper process aid for the application

With the advent of new and demanding applications such as foam core pipe and coextruded siding and profile, coupled with the demand for more highly efficient cost/performance products in older PVC applications resulting from the desire to increase output, and with the push towards recycling, there is a strong need for efficient and effective processing aids. Process aids have been used for many years to improve the appearance and properties of PVC. In the past they were limited to low and high molecular weight products (0.3 to 0.5 reduced viscosity value), lubricating type acrylics, and some lower-efficiency styrenics. This paper will describe a much broader range of process aids that are designed to fit the requirements of specific formulation and processing techniques. Rather than force fitting the few older processing aids into all applications, the PVC processor now has the luxury of optimizing his formulation by choosing from a wide molecular weight range of products (0.1 to 0.9 reduced viscosity value). The different structures and molecular weights of currently commercial process aids are discussed, as well as their “fit” in today's formulations.