填料类型对 PVC 密封垫蒸发残渣的影响

实验研究了填料类型、粒径大小和用量对 PVC 密封垫蒸发残渣卫生性能的影响。 结果表明:4 种填料均可用于水性和酒性产品包装的密封材料中,针状填料 T4 适宜于酸性产品密封料,油性产品密封料除优选填料外,还需对增塑剂进行筛选;填料目数越小,蒸发残渣越大,在可生产的黏度范围,可增加填料用量。     

食品包装用PVC中的物质在5种介质中总迁移规律的研究

采用红外光谱技术对PVC食品包装材料进行了鉴定分析,并通过蒸发残渣方法,重点研究了不同条件下PVC中物质的总迁移规律。结果表明,PVC产品中含有较高含量的邻苯(脂肪族)二甲酸酯类增塑剂等非挥发性化学物,极易在高温下迁移到脂类食品模拟液中。其物质总迁移量大小顺序为:95%乙醇≥正己烷水≈4%乙酸≈20%乙醇。PVC中物质的总迁移量在高温下是相对较高的,且随迁移时间的延长而增加。     

聚氯乙烯瓶盖垫蒸发残渣的检测与分析

以质量法和面积法为基准,对聚氯乙烯(PVC)瓶盖垫蒸发残渣量测定方法进行了研究和分析,探讨了样品形状和用量对PVC瓶盖垫蒸发残渣量的影响。结果表明:采用面积法测试蒸发残渣的量大于质量法测试的,且测试样品制成垫圈形式时,测试的蒸发残渣量比制成垫片形式的样品蒸发残渣量大;样品用量对基于质量法的蒸发残渣测试结果影响很大,但对基于面积法的测试结果影响不明显。     

软包装企业的食品包装——安全问题及解决措施

一、食品用塑料包装材料的危害因素 （一）塑料制品以合成树脂为主要原料,添加适量的增塑剂、稳定剂、抗氧化剂等助剂,在一定的塑化条件下加工而成。食品包装常用塑料是聚乙稀（PE）、聚丙烯（PP）、聚酯（PET）和聚氯乙烯（PVC）。食品包装用树脂本身是无毒的,但其单体和降解产物毒性较大。因为加工过程中加八一些助剂,或非法使用一些助剂（如一些PVC保鲜膜加入DEHA增塑剂）,以及加工工艺和生产设备简陋,使塑料树脂中残留单体超量或产生有毒有害物质,可对食品造成污染,威胁人体健康。     

乙酸纤维素游离膜的吸湿性

研究了以乙酸纤维素为原料，丙酮为溶煤，用平面铸膜法制备的乙酸纤维素游离膜的吸湿性的特点．结果表明，游离膜的吸湿量和表观膜厚没有关系，仅与致密层厚度相关；增塑剂可增加膜的吸湿性，不同增塑剂对改善膜的吸湿性影响程度不同．     

聚氯乙烯搪塑粉料用低挥发损失率复合热稳定剂的制备及性能

以市售液态钙锌稳定剂T1为主原料,按一定比例复配偏苯三甲酸三辛酯以保护钙/锌皂盐的活性,并将该混合液于140℃恒温蒸发120min,使原液态钙锌稳定剂中稳定性差的助剂得以挥发,得到适用于聚氯乙烯(PVC)搪塑粉料的复合热稳定剂T2,进而制备PVC搪塑表皮,并测试其挥发损失率和热稳定性等性能。结果表明,与市售液态钙锌稳定剂T1相比,添加了自制稳定剂T2的PVC搪塑表皮的挥发损失率显著降低,同时表皮的热稳定性和抗热老化性能都得到改善。     

线性判别分析法在塑料食品包装容器溶出物的风险聚类分析中的应用

报道了为考察塑料食品包装容器蒸发残渣因不同材料造成的质量差异,并对不同材质蒸发残渣指标进行风险聚类,提高检测针对性的方法.对塑料食品包装容器在水、乙酸、乙醇、正己烷浸泡条件下的蒸发残渣含量进行测定,使用四分位稳健统计描述来表征不同使用条件下的溶出风险,使用线性判别法分析对不同材质塑料包装容器蒸发残渣进行了风险聚类分析.结果表明:包装容器的油性溶出风险最高,水的溶出风险最低;包装容器蒸发残渣含量水平可基本划为两类,即"PET-PP-PE"类与"PS-其它类";采用适合的数据描述及多元统计分析方法,可有效地加强食品包装风险监控力度,提高监控效率.     

聚氯乙烯与热塑性聚氨酯共混材料的制备及性能

采用挤出注塑的方法制备聚氯乙烯(PVC)和热塑性聚氨酯(TPU)共混材料。探讨了PVC与TPU共混比、增塑剂、热稳定剂、填料等因素对共混材料拉伸强度、断裂拉伸应变等力学性能的影响。结果表明:PVC/TPU(质量比)为70/30,增塑剂为50份,稳定剂为2份,纳米活性碳酸钙为30份时材料的力学性能较好,实现了对PVC的增韧。     

淀粉/ PVA挤出发泡复合材料的 流变行为及泡孔形态

将木薯淀粉、聚乙烯醇(PVA)及其他各种助剂共混,通过挤出成型制备了一种可生物降解的复合发泡材料。采用L16(45)正交试验,探讨了淀粉添加质量分数、NaHCO_3发泡剂添加质量分数、甘油/NaOH水溶液复合增塑剂添加质量分数、温度及剪切速率对淀粉/PVA发泡复合材料流变行为的影响,并采用SEM研究了不同熔体黏度对材料泡孔形态的影响。研究结果表明,随着淀粉添加质量分数的增加,材料的熔体黏度升高;随着NaHCO_3发泡剂和甘油/Na OH水溶液复合增塑剂添加质量分数的增加,材料的熔体黏度下降;随着温度的升高和剪切速率的加大,材料的熔体黏度先降低后升高,在温度为145℃、剪切速率为500 s-1时,材料的熔体黏度最低;当熔体黏度为1 600 Pa·s时,材料的泡孔形态较佳。     

PVC包装薄膜所产生的环保问题

PVC包装薄膜大多是由聚氯乙稀树脂，通过添加增塑剂，稳定剂等多种助剂经加工塑化而成。由于其材料特性．聚氯乙稀包装薄膜除了在使用过程中与食品接触会产生安全问题外．其废弃物对生态环境同样会产生严重的不良影响，     

食品包装用PVC瓶盖垫片中增塑剂DEHP的迁移研究

为了解PVC垫片接触各类食品的安全性,采用气相色谱-质谱联用法研究了PVC垫片中DEHP在乙醇和正己烷中的迁移行为及其影响因素。实验结果表明:随着时间的延长,DEHP的迁出量逐渐增加;PVC垫片厚度越小,DEHP越容易迁出;与乙醇相比,DEHP更容易向正己烷中迁移,PVC垫片应避免接触脂肪类食品。     

PVC搪塑粉的热降解特征及其动力学研究

粉末搪塑表皮被广泛应用在各种中高档汽车仪表板上.为了优化设计搪塑粉、提高热加工性能从而促进高档汽车国产化,本文首先利用热重分析和裂解气相色谱/质谱实验探讨搪塑粉的热降解失重特征,分析升温速率、实验气氛和搪塑加工对其热降解行为的影响,继而结合X射线荧光光谱实验对其热降解动力学进行研究.结果表明:搪塑粉的热降解过程可分为3个阶段,PVC和增塑剂的相互作用使其热降解过程更加复杂;随升温速率的增加,热降解失重曲线向高温区偏移;搪塑粉在有氧气氛中更易发生热降解,失重率较大;与搪塑粉相比,搪塑表皮的热稳定性能得到一定程度的提升;第1热降解阶段氮气条件下的热降解活化能和反应级数较小.     

Blood response to plasticized poly(vinyl chloride): dependence of fibrinogen adsorption on plasticizer selection and surface plasticizer level

The high level of plasticizer in plasticized poly(vinyl chloride) (PVC) ensures that plasticizer selection has an important influence on the suitability of PVC to function in blood-contacting applications. In this study, three types of plasticized PVC in sheet form, with di-(2-ethylhexyl)phthalate (DEHP), tri-(2-ethylhexyl)trimellitate (TEHTM) and n-butyryltri-n-hexyl citrate (BTHC) as plasticizer, were selected for assessment and single solute fibrinogen adsorption was utilized as an initial index of interactions with blood components. Fibrinogen adsorption behavior shows a strong dependence on the plasticizer selection, plasticizer level at the surface and the adsorption conditions, such as adsorption time and fibrinogen solution concentration. Results indicate that BTHC plasticized PVC possesses the lowest adsorption capacity in the three types of plasticized PVC, while TEHTM plasticized PVC seems to have the strongest reactivity in certain fibrinogen solution concentrations. The alteration of surface plasticizer level was achieved by a methanol-cleaning treatment with a variety of cleaning times and the fibrinogen adsorption on plasticized PVC decreases with the reduction of surface plasticizer level. The migration behavior of two phthalate esters (DEHP and TEHTM) was evaluated using UV-Spectrophotometer to determine the plasticizer level at the surfaces. In addition, the fibrinogen adsorption mechanism was examined with Freundlich adsorption modeling.     

谈聚氯乙烯膜的功能特点及其应用领域

PVC材料的使用非常有利于环境保护,其自身的安全性是非常理想的。PVC与添加荆混合、塑化后,利用三辊或四辊压延机制成规定厚度的透明或着色薄膜,用这种方法加工薄膜,成为压延薄膜。也可以通过剪裁,热合加工包装袋、雨衣、桌布、窗帘、充气玩具等而应用广泛。针对聚氯乙烯膜的功能特点及其用途,介绍了聚氯乙烯膜的应用种类,研究了聚氯乙烯薄膜配方设计要点,分析了聚氯乙烯吹塑薄膜增塑剂系统的选择,提出了聚氯乙烯薄膜的制作工艺。     

Effect of the epoxidized linseed oil concentration as natural plasticizer in vinyl plastisols

The use of natural-based additives as plasticizers for plasticized Polyvinyl Chloride (p-PVC) has been evaluated in this study. PVC traditional plasticizers based in phthalate have been substituted by epoxidized linseed oil (ELO). From the industrial point of view, this substitution presents an interesting alternative because ELO is a natural product, harmless, and biodegradable. The effects on the characteristics of plasticized PVC in the migration phenomenon have been analyzed. This analysis has been done from the point of view of optimizing the curing process parameters: the amount of plasticizer, temperature, and curing time. The use of these new plasticizers with low toxicity and low migration reduce significantly the toxic risks of the management of this kind of polymers. The curing process has been optimized through the study of the migration characteristics in accordance with the isothermal curing process from 140 to 220 °C in curing periods ranging from 6 to 14 min. The obtained results present a weak tendency toward the migration of the plasticizer with a curing temperature of 220 °C during 8 min. The determination of mechanical and micro-structural properties with Scanning Electron Microscope (SEM) techniques has allowed us to conclude that the optimal addition of ELO as plasticizer is in the range of 70–80 phr, under the optimal curing conditions.     

食品接触材料中多种添加剂迁移量的测定

目的建立食品接触材料中32种添加剂迁移量的高效液相色谱检测方法,调查市售塑料食品接触材料中32种添加剂的迁移水平。方法选取103批不同材质的塑料食品接触材料,采用异辛烷、乙醇(体积分数分别为50%,20%,10%)、质量分数为3%的乙酸浸泡样品,得到模拟液,用液相色谱仪分析,外标法定量。结果 DBP,DEHP,二苯酮,UV-1577,BHT,697,2246,BHEB和荧光增白剂184均有检出,其中11批PVC样品中DBP或DEHP、1批PP样品中二苯酮和1批PC样品中UV-1577的迁移量高于限量要求。上述添加剂在异辛烷模拟物中的检出率最高,在体积分数为50%的乙醇模拟物中有较低的检出率,在其他3种模拟物中均未检出。结论塑料食品接触材料不宜直接用于接触油类食品和浓度较高的酒类食品。PP材质中的二苯酮、PC材质中的UV-1577、PVC材质中的DBP和DEHP存在的潜在危害较大,应加强监管。     

Synthesis and application of a novel environmental C26 diglycidyl ester plasticizer based on castor oil for poly(vinyl chloride)

A castor oil-derived diglycidyl ester plasticizer (C26-DGE) was prepared and incorporated into poly(vinyl chloride) (PVC) for the first time. The chemical structure of the product was characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H-NMR), and carbon-13 nuclear magnetic resonance (¹³C-NMR). The plasticizing effects of C26-DGE as a primary or secondary plasticizer for the commercial plasticizer dioctyl phthalate (DOP) were studied. The mechanical properties, thermal stability, and migration stabilities of PVC films were investigated using dynamic mechanical analysis, thermogravimetric analysis (TGA), TGA-FTIR analysis, and PVC film surface analysis. Tensile, volatility, and extraction tests were also done. The castor oil-based plasticizer was found to endow the PVC matrix with enhanced compatibility and flexibility. With partially or completely substituted DOP, C26-DGE significantly increased the thermal stability of PVC blends. Furthermore, the volatility and extraction resistance of the novel plasticizers were generally superior to those of DOP. The interaction between the C26-DGE and PVC molecules and the thermal degradation process of PVC blends were also investigated.     

聚酯增塑剂的合成及对PVC的增塑

通过熔融缩聚的方法,合成了己二酸丙二醇型聚酯增塑剂,将其作为辅助增塑剂用于软质PVC的制备,期望达到降低聚氯乙烯(PVC)主增塑剂邻苯二甲酸二辛酯(DOP)迁移和抽出的目的。通过引入第三单体三羟甲基丙烷,并控制第三单体的加入量,合成了具有不同支化度的聚酯,并对PVC进行增塑试验,考察了聚酯的支化度及相对分子质量对PVC增塑效果的影响。实验结果表明,所合成的不同分子量聚酯增塑剂与PVC树脂的相容性均良好,当采用较高分子量聚酯或较低支化度聚酯时,其增塑PVC材料的玻璃化转变温度较低,所显示的增塑效率较高,材料的热稳定性能较好。