浅谈薄膜热封特性及热封效果

在袋装及裹包等包装应用中，柔性材料中的封口是很重要的，其中软塑包装及其 合材料的热封是常用的封口形式，但塑料薄膜热封性能受到方面因素的综合影响，有时往往也会形成较难的热封控制条件。在此主要讨论可热土瓣热封特性及其影响因素，浅述其一般规律；同时提出准确评价热封效果的理论和手段，用于指导生产实践。     

包装材料EPE热封工艺的实验研究与分析

目的研究EPE包装袋的热封质量与热封参数(电热丝直径、热封时间、热封压力)的关系,分析弹性包装材料热封过程的特性。方法通过观察显微封口形貌,比较不同参数下的热封强度,研究热封参数对珍珠棉热封强度的影响,并分析其原因。结果在热封1.0 mm珍珠棉过程中使用直径为0.8 mm电热丝,热封压力为0.2 MPa,热封时间为2 s时,热封质量最好、效率较高。结论弹性材料的可压缩性导致封切压力对热封强度的影响随电热丝直径的增加而明显增加,弹性材料的回弹特性使电热丝直径以及热封时间对其热封缺陷产生更加显著的直接影响。     

熟制玉米的蒸煮袋包装设计

将高温蒸煮技术与熟制玉米的包装相结合,围绕蒸煮袋的结构、选材及材料厚度的确定等内容对熟制玉米进行蒸煮包装设计。根据被包装玉米的尺寸及性能要求,设计该蒸煮包装袋为四面封口的直立袋结构,包装尺寸为24.5 cm×12.5 cm,材料结构为PET15/PA15/PVDC7/CPP50;并根据熟制玉米的最大允许透水量、设计所用材料的透湿系数和厚度对材料进行保质期验算。通过对所设计蒸煮袋的热封试验,确定了其最佳热封参数:热封压力为50~100 kPa,热封温度为135~145℃,热封时间为2~3 s。     

浅析热封界面的密闭性能

软塑材料的制袋与封口是包装流水线上一个关键性的配套工序,由它决定的袋口热封性能,则是任何商品包装性能的重要指标之一。不难设想,倘若热封后,封口部位残存着某种薄弱环节,那么这里就将隐伏着封口界面脱层的危险。情况一旦发生,势必会造成商品污染、食品变质,最终损害商品信誉,给企业带来不可     

中国兵器工业第五九研究所包装工程技术研究中心

正防静电材料通过导电填料表面改性处理、优化配方及工艺参数,使材料具有良好综合机械力学性能,同时赋予包装材料永久性抗静电的功能。主要技术指标及特点:表面电阻率≤1×10~8Ω断裂伸长率≥100%热封强度≥40 N/15mm①黑色永久防静电膜②透明防静电膜③火工品防静电包装④电子仪器防静电包装     

中国兵器工业第五九研究所包装工程技术研究中心

正防静电材料通过导电填料表面改性处理、优化配方及工艺参数,使材料具有良好综合机械力学性能,同时赋予包装材料永久性抗静电的功能。主要技术指标及特点:表面电阻率≤1×10~8Ω断裂伸长率≥100%热封强度≥40N/15mm①黑色永久防静电膜②透明防静电膜③火工品防静电包装④电子仪器防静电包装     

中国兵器工业第五九研究所包装工程技术研究中心

正防静电材料通过导电填料表面改性处理、优化配方及工艺参数,使材料具有良好综合机械力学性能,同时赋予包装材料永久性抗静电的功能。主要技术指标及特点:表面电阻率≤1×10~8Ω断裂伸长率≥100%热封强度≥40N/15mm①黑色永久防静电膜②透明防静电膜③火工品防静电包装④电子仪器防静电包装     

《塑料包装技术》连载挤出薄膜和软包装之四--热封合

通常热封依赖于热和压力的结合，把两层热塑性塑料材料熔合在一起。当材料之间的接触面消失，热封合是最牢固的，被封合的材料没有变薄或减少。在包装中使用多种类型的热封合。其中一些方法被应用到硬质包装，而不是软包装。这里对这些方法已全部讨论过了。     

如何获得包装材料最准确的热封性能

1　软包装封口强度的检测意义封口强度对包装材料来讲是一个重要性能指标 ,对任何一种软包装材料都要做成包装袋来包装各种商品 ,包装商品都要热封或粘接来封口 ,达到包装目的。封口要有一定的强度才能够承受一定重量的内装物的压力 ,保证商品在流通过程中不开裂。热封是利用外界条件 (电加热、超声波等 )使塑料薄膜的封口部位变成粘流状态 ,借助刀具压力使薄膜融合为一体 ,冷却后能保持一定强度。热封工艺的三大因素热封温度、压力、时间 ,其中主要是温度。根据材料的不同和料袋运动状态需要不同的热封因素 ,三者必须协调配合才能获得好的…     

材料的热粘性与热封强度

详细分析了软包装材料热粘性与包装生产效率之间的关系,并给出了几种材料热粘性和热封强度的比较数据.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.