引发剂用量对丙烯酸树脂乳液及涂膜性能的影响

以粒径、单体转化率、凝胶率及涂膜的吸水率和抗张强度为考察指标,实验研究了引发剂用量对丙烯酸树脂乳液及涂膜基本性能的影响。结果表明:乳液粒径在引发剂用量超过0.5%以后达到最小值,并趋于平稳;而凝胶率在引发剂用量0.5%时最低,涂膜的吸水率在引发剂用量0.6%时达到极大值;引发剂用量对涂膜的伸长率影响不大,在用量超过0.3%时机械强度增加不显著,并趋于平衡。建议制备丙烯酸树脂乳液时,引发剂用量占单体总量的0.5%为宜。     

食品接触塑料中化学成分迁移研究方法进展

塑料以其优良的物理化学性能和低廉的价格广泛应用于食品接触制品中。然而食品长期与塑料包装接触可能导致塑料中化学成分向食品中迁移,进而造成食品污染,并最终危害消费者的身体健康。故食品接触塑料中化学成分的迁移行为受到国内外政府机构和科研工作者的广泛关注。本文简述了食品接触塑料迁移实验中食品模拟物的选择、迁移实验条件的设定,以及受限物质的检测方法。并对食品接触塑料中的光引发剂、重金属元素、增塑剂等三类化学成分的迁移规律的研究进行综述。     

光引发剂对UV柔印油墨稳定性的影响

为了研究光引发剂对UV柔印油墨稳定性的影响,使用3种光引发剂制备UV柔印品红油墨样品,对光引发剂种类对油墨稳定性的影响进行了研究。通过改变光引发剂907的含量制备油墨样品,研究了光引发剂含量对油墨稳定性的影响。结果表明,光引发剂种类及含量对UV柔印油墨稳定性有很大影响,主要影响油墨的黏度和固化速度。光引发剂TPO所制备的油墨具有较好的储存稳定性;光引发剂907用量为8%时,油墨能保持较好的黏度稳定性,且具有最高的固化速度。     

光引发剂对水性UV光油固化性能的影响

光引发剂是引发UV光油体系固化的关键组分.为了考察光引发剂对光油固化性能的影响,设计了水性UV光油的基本配方,采用4种单一光引发剂分别制备光油样品,测试各样品的固化效果并进行比较分析.实验结果表明,光引发剂的种类及用量对光油的固化效果影响很大,其中光引发剂907制备的光油固化速率最快,光油涂膜黄变性较小;光引发剂1173制备的光油涂膜基本不发生黄变.运用配方设计试验法,以光引发剂907、TPO及ITX组成复合光引发剂制备光油样品,考察其对光油固化性能的影响,结果表明其体系固化速率低于单一光引发剂907.使用单一光引发剂907的用量为6％时,UV光油样品的固化效果最好.     

超高压液相色谱法测定食品接触材料印刷油墨中光引发剂

目的 建立超高压液相色谱-二极管阵列检测器(UPLC-DAD)快速测定食品接触材料表面印刷油墨中光引发剂的分析方法。方法 采用65%和正己烷作为食品模拟物模拟含酒精和脂肪食品, 分别在5 ℃和40 ℃的温度下进行240 h的迁移试验。迁移后的模拟液经浓缩、净化、重新溶解并过滤后直接进样分析。结果 线性范围为0.1~500.0 μg/L, 检出限为0.005 μg/dm2, 空白样品的加标回收率为79.8%~92.3%。采用UPLC-DAD对30余种食品接触材料中光引发剂种类和含量进行了测定。ITX和EHDAB在食品接触材料中一般协同出现, 其迁移水平分别为0.11 μg/dm2和0.092?0.370 μg/dm2。结论 超高压液相色谱-二极管阵列检测器(UPLC-DAD)可以用于快速测定食品接触材料表面印刷油墨中光引发剂。     

UV油墨固化速率的影响因素研究

UV油墨固化速率不仅受到油墨中各组分的影响,而且与墨膜厚度有密切关系.本研究分别使用不同种类的预聚物、单体、光引发剂配制油墨,研究油墨各组分对UV油墨固化速率的影响;进而固定油墨其他组分,改变光引发剂种类及其含量配制油墨,并制备不同墨层厚度的样品,测试不同墨层厚度下的油墨预聚物双键转化率,分析光引发剂种类及其含量与不同厚度墨膜固化速率的关系.测试不同UV光源功率下的双键转化率,研究含不同光引发剂的油墨在不同功率下的固化速率.研究结果表明,油墨各组分对UV油墨固化速率有一定影响,此外,随着墨层厚度的增大,油墨双键转化率降低;当光引发剂含量小于10％时,UV油墨的固化速率随着光引发剂含量的增加而增大;UV油墨的双键转化率随着UV光源功率的增大而增大.     

顺丁烯二酸/甲基丙烯酸甲酯共聚物的合成

选用顺丁烯二酸(分析纯)和甲基丙烯酸甲酯(分析纯)为共聚物单体,过氧化苯甲酰为引发剂,通过本体聚合法制备主浆料。研究了单体配比、加热时间、反应温度、引发剂用量对共聚物性能的影响,并利用红外光谱、热重分析仪对共聚物进行了表征。通过试验优化,当单体物料比为1∶2,加热时间为5h,反应温度为68℃,引发剂用量为9%时,制备的顺丁烯二酸/甲基丙烯酸甲酯共聚物成分均匀,重均分子量为7.970×105,200℃以下热稳定性良好。     

引发剂对淀粉接枝共聚反应影响的研究

本文研究了经过酸解处理的改性淀粉与醋酸乙烯酯的接枝共聚反应，主要分析了引发剂对淀粉接枝共聚反应的影响。研究发现，引发剂对淀粉接枝共聚反应的影响非常显著。在摩尔浓度相同的情况下，过硫酸铵对该体系的引发效果最佳；且过硫酸铵引发剂采取分阶段加入的方式有利于接枝共聚反应的进行，第一次在酸解开始时加入，这样既可以达到预引发的目的，还能对淀粉起到一定的氧化作用；第二次在接枝反应开始1．5h后加入；两次引发剂的最佳用量分别为淀粉干基质量的2．2％和0．45％。     

芦苇乙醇木质素与丙烯酰胺接枝共聚的研究

以(NH4)2S2O8和NaHSO3作为引发剂,研究了芦苇乙醇木质与丙烯酰胺的接枝共聚反应中丙烯酰胺用量、引发剂用量、引发剂配比、反应温度、反应时间等因素对产率和接枝效率的影响规律,并对实验条件进行优化.确定最优条件为丙烯酰胺单体与乙醇木质素的质量比为11,引发剂用量为50mmol/L,引发剂(NH4)2S2O8与NaHSO3的摩尔比为41,反应温度80℃,反应时间4h.最优条件下产物产率达到95%,接枝效率为90%.红外光谱分析证实了产物中存在接枝共聚物,并且主要以醚键连接.     

光引发剂对UV丝印光致变色油墨固化性能的影响

UV丝印光致变色油墨体系中主要包括了预聚物、单体、光致变色材料、光引发剂等成分,而此油墨的固化是在UV光源的照射下,引发具有化学反应活性的液态物质快速转变为固态的过程,光引发剂在此化学反应中的作用就是引发这种反应进行,因此,它是油墨体系中直接影响着油墨固化性能的主要成分之一。通过改变光引发剂的含量和种类,分别制备油墨,并测试油墨的固化速度,从而研究光引发剂对油墨的固化性能的影响。实验表明当光引发剂的含量为10%的时候,油墨的光固化性能最好。另外选出三种固化性能最好的光引发剂184、907和BP进行配方实验,结果表明由光引发剂907所制备的油墨具有最好的固化性能,并且,最佳的固化速度为68m/min(固化功率:100W/cm)。     

Non-visible print set-off of photoinitiators in food packaging: detection by ambient ionisation mass spectrometry

Direct analysis in real time coupled to time-of-flight mass spectrometry (DART/TOF-MS) was used to detect the non-visible set-off of photoinitiators on the food contact surface of three different packages. The samples were intentionally under-cured to provoke set-off. Twelve commercially available photoinitiators were included in the ink formulations including α-amino-, morpholino, and α-hydroxy benzophenones, thioxanthones, aryl-phosphine oxide and three polymeric versions of these. Major colours of the packages’ prints were analysed, as well as the specific areas of the inner surface in contact with them. Larger quantities of photoinitiators were detected on the food contact areas in contact with the darker colours of the images. Speed-cure 7005 and 4-phenylbenzophenone were the compounds most susceptible to set-off in each of the samples by DART response. An identification protocol for unknown set-off compounds was tested, resulting in the set-off detection of diethylene glycol ethers, erucamide and acrylates, and confirmed by solvent extraction GC-MS analysis. Finally, DART/TOF-MS was scanned across transects of the food contact side of packages to map the presence of photoinitiators. Higher photoinitiator signals were observed in patterns corresponding to the printed image, suggesting DART/TOF-MS might “image” print set-off.     

Migration of photoinitiators from paper to fatty food simulants: experimental studies and model application

The migration of five different photoinitiators from kraft paper to two fatty food simulants, Tenax^® and 95% ethanol, was investigated under different conditions. The effects of temperature and storage time, as well as the physicochemical properties of the photoinitiators on migration, were discussed. Mathematical models based on Fick’s second law generated from two cases, single- and two-side contacts, were applied to predict the migration behaviour from the paper to the food simulants. The partition coefficients estimated from the model decreased with temperature. The diffusion coefficients of the selected photoinitiators from the paper ranged from 1.55 × 10^–10 to 7.54 × 10^–9 cm² s^?1 for Tenax and from 2.79 × 10^–9 to 8.03 × 10^–8 cm² s^?1 for 95% ethanol. The results indicate that the applied model can predict the migration of photoinitiators in the initial short period before equilibrium, and the migration from paper to Tenax through a single-side contact demonstrated an especially high concordance.     

气相色谱-质谱法检测湘式挤压糕点中4种光引发剂

目的建立气相色谱-质谱法测定湘式挤压糕点中4种光引发剂的方法。考察不同提取溶剂及净化方式对检测结果的影响。方法试样经丙酮-正己烷超声提取,采用PSA管进行净化,采用EI源以气相色谱-质谱法进行检测。结果添标水平为0.005～0.02 mg/kg时的平均回收率在85%～110%间,相对标准偏差为5.7%～9.1%,4-氯二苯甲酮的方法检出限为0.008 mg/kg,其余3种光引发剂的检出限为0.005 mg/kg。结论该方法快速,简单,灵敏度高,符合检测方法参数的确认要求。     

Migration of photoinitiators from cardboard into dry food: evaluation of Tenax® as a food simulant

Photoinitiators are widely used to cure ink on packaging materials used in food applications such as cardboards for the packaging of dry foods. Conventional migration testing for long-term storage at ambient temperature with Tenax^® was applied to paperboard for the following photoinitiators: benzophenone (BP), 4,4?-bis(diethylamino)benzophenone (DEAB), 2-chloro-9H-thioxanthen-9-one (CTX), 1-chloro-4-propoxy-9H-thioxanthen-9-one (CPTX), 4-(dimethylamino)benzophenone (DMBP), 2-ethylanthraquinone (EA), 2-ethylhexyl-4-dimethylaminobenzoate (EDB), ethyl-4-dimethylaminobenzoate (EDMAB), 4-hydroxybenzophenone (4-HBP), 2-hydroxy-4-methoxybenzophenone (HMBP), 2-hydroxy-4?-(2-hydroxyethoxy)-2-methylpropiophenone (HMMP), 2-isopropyl-9H-thioxanthen-9-one (ITX), 4-methylbenzophenone (MBP) and Michler’s ketone (MK). Test conditions (10 days at 60°C) were according to Regulation (EU) No. 10/2011 and showed different migration patterns for the different photoinitiators. The results were compared with the migration in cereals after a storage of 6 months at room temperature. The simulation with Tenax at 60°C overestimated actual migration in cereals up to a maximum of 92%. In addition, the effect of a lower contact temperature and the impact of the Tenax pore size were investigated. Analogous simulation performed with rice instead of Tenax resulted in insufficiently low migration rates, showing Tenax is a much stronger adsorbent than rice and cereals.     

Development of an analytical method for the determination of photoinitiators used for food packaging materials with potential to migrate into milk

Photoinitiators are used in the curing process during UV printing of food carton labels. The alarm concerning the detection of a photoinitiator, 2-isopropyl thioxanthone (ITX), in food samples packed with cartons printed with UV-cured inks has focused the attention of legislative authorities on the potential migrants from packaging inks into foods. For this reason it is very important to carry out analytical methods for the detection of those compounds in food as potential migrants from packaging. The aim of the present work was to develop a multimethod for the analysis of 6 photoinitiators in milk. The selected photoinitiators were Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, Quantacure ITX, and Quantacure EHA (2-ethylhexyl-4-dimethylaminobenzoate). Milk (10 mL) extraction was carried out by using ammoniac and hexane. The supernatant was evaporated and the residue was redissolved with acetonitrile. Then, the extract was analyzed by HPLC-UV. Calibration lines were carried out over the concentration range of 0.1 to 10 mg/L. The calibration data presented high correlation coefficients (>0.9999). Mean recoveries (n = 6) of the 6 photoinitiators were 83.4% (residual standard deviation = 2.3%) at 0.5 mg/kg and 81.0% (residual standard deviation = 4.6%) at 1 mg/kg. Several milk samples and their respective packaging cartons were analyzed. Results were confirmed by HPLC-mass spectrometry.     

Photoinitiators: a food safety review

Ultraviolet light printing inks are considered safer than the classical inks; however, despite being on the outer surface of the packaging material, their components can migrate into foodstuffs and can give rise to contamination. Photoinitiators are a part of the formulation of printing inks, being an important class of migrant, for which there have been more than 100 incidents of contamination of packaged food with photoinitiators reported through Rapid Alert System for Food and Feed (RASFF) alerts in the European Union. In this review the process of photo-polymerisation is explained in depth to provide an insight into the complexity of the process, and the diversity of potential contaminants together with their degradation products. The critical factors affecting the migration process itself are reviewed, together with analytical methods and the current legislation in the European Union and other parts of the world.     

光交联丝素蛋白水凝胶的蓝光引发体系

针对再生丝素蛋白水凝胶生物活性、凝胶效率及凝胶强度三者难以兼具的问题,用樟脑醌(CQ)、核黄素磷酸钠(FMN)、曙红Y(EY)及姜黄素4种生物相容的光敏剂,分别与二芳基六氟磷酸碘鎓盐(DPI)构成丝素蛋白水凝胶的高效蓝光交联引发体系。借助紫外分光光度计和光差示扫描量热法研究了4种光引发体系的光谱吸收特性和蓝光引发效率,采用光流变系统研究了光交联丝素蛋白的凝胶化行为。结果表明:CQ/DPI、EY/DPI体系均可作为自由基聚合以及丝素蛋白光交联反应的良好蓝光引发体系,该蓝光引发体系诱导丝素蛋白酪氨酸残基自由基间的偶合反应是丝素蛋白光交联反应的主要机制;以EY/DPI体系引发低浓度丝素蛋白光交联反应可在短时间(10 min)内实现较高强度丝素蛋白水凝胶的制备。     

低温下采用快速液相色谱-质谱联用法分析包装食品中UV油墨光引发剂的迁移

A fast method of liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS) was developed for the analysis of eleven UV ink photoinitiators in packaged food.Chromatographic separation was achieved in a pentafluorophenylpropyl (PFPP) column at 5X2 and acetonitrile:25mM formic acid-ammonium formate(pH 2.7) in gradient elution. To reduce sample treatment,a QuEChERS(quick,easy,cheap,effective,rugged and safe) method for the extraction and clean-up of UV photoinitiators in packaged foods was evaluated.Triple quadrupole working in H-SRM on Ql mode was used for both quantitation and confirmation purposes and the most intense and selective transitions were chosen.Quality parameters of the developed QuEChERS LC-MS/MS method were established and applied for the analysis of photoinitiators in food packaged at ng/kg levels.     

高效液相色谱串联二级管阵列检测器和荧光检测器测定金属包装彩印面3种光引发剂迁移量的不确定度评定

目的评定高效液相色谱串联二级管阵列检测器和荧光检测器(high performance liquid chromatographydiode array detector-fluorescence detector,HPLC-DAD-FLD)测定金属包装彩印面3种光引发剂迁移量的不确定度。方法依据JJF 1059.1-2012《测量不确定度评定与表示》,对光引发剂迁移量测定过程中的不确定度来源进行分析和量化评定。结果本研究测得的某金属包装彩印面中光引发剂的迁移量分别为二苯甲酮(benzophenone,BP)为(0.3211±0.0226)mg/L(k=2)、4-甲基二苯甲酮(4-methyl benzophenone,4-MBP)为(0.3210±0.0244)mg/L(k=2)和2-异丙基硫杂蒽酮(2-isopropyl thioxanthone,2-ITX)为(0.0377±0.0067)mg/L(k=2)。不确定度主要来源于标准曲线拟合、标准物质称量和样本估计总体。结论本研究可为HPLC-DAD-FLD法测定金属包装彩印面中3种光引发剂迁移量的测量准确性提供参考。     

Development of a multimethod for the determination of photoinitiators in beverage packaging

ABSTRACT:  Photoinitiators are ink components used in the printing of food packaging. The aim of the present study was to develop a multimethod for the analysis of photoinitiators in paperboard packages and commercial beverage packages. The proposed method is simple and fairly rapid. Extraction is carried out with acetonitrile. A reverse-phase high performance liquid chromatography (HPLC) method with UV detection was developed to quantify the 6 selected photoionitiators. Total HPLC time analysis was 30 min and the flow-rate was 1 mL/min. Method validation parameters such as linearity and detection limit are reported. Recovery of all photoinitiators (at 1 mg/kg) from orange juice was satisfactory (mean = 88.4%; ranging from 84.6% to 93.4%). Recovery of benzophenone and Irgacure 651 was good (ranging from 85.2% to 98.1% and 86.1% to 92.2%, respectively) at the 4 concentrations studied (0.1, 0.2, 0.5, and 1 mg/kg). Commercial beverage packages were analyzed and when photoinitiators were detected, the beverages were also analyzed.