Dynamic Buffering Performance of the Honeycomb Paperboard Filled with Polyurethane

A new kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results, we analyzed the mechanical behaviors of the material under different conditions and obtained the inherent influencing laws of some factors on the material＇s dynamic buffering performance. It was shown that the dynamic buffering performance varied directly with impact velocity, and inversely with the void diameter, thickness and buffeting area of the composite material.

Comparison Studies on Dynamic Packaging Properties of Corrugated Paperboard Pads

Corrugated paperboard is a kind of inexpensive and environmental-friendly packaging material, and may be made into pads of package cushioning to protect products from shock and vibration damage by isolation during distribution. This article deals with the characterization of dynamic packaging properties of corru-gated paperboard pads, such as dynamic cushioning curves, vibration transmissibility and frequency curves. The main feature of article is the evaluation on the dynamic shock cushioning property and vibration trans-missibility of corrugated paperboard pads by a series of experimental studies on the drop shock tester and vibration tester, the establishment of experimental formulas of dynamic cushioning curves, and the analysis of resonance frequencies and vibration transmissibility. By using the fitting polynomial of curve and method of the least mean square, the experimental formulas with third order polynomial function of dynamic cush-ioning curves for corrugated paperboard pads are obtained. By using linear vibration theory with single de-gree of freedom, the resonance frequencies, vibration transmissibility and damping ratios of corrugated pa-perboard pads at different static loads are acquired. All results show the dynamic properties relevant to de-sign applications of corrugated paperboard pads for protective packaging.

Water and Oil Resistance of Special Paperboard for Petroleum Packaging

The influence of different coating formulas and times on the water and oil resistance of paperboard was studied. The water and oil resistance of paperboard coated with a modified butadiene-styrene copolymer latex and fluorinated anion grease-proof agent was better than that coated with modified butadiene-styrene copolymer latex,where the modified butadiene-styrene copolymer latex was used as the pre-coating substrate and the F1516 fluorinated grease-proof agent was used as the top coating material. By coating modified butadiene-styrene copolymer latex with 30% solid content and F1516 fluorinated grease-proof agent with 24% solid content,the oil resistance of paperboard could reach anti-oil grade 12 and the water resistance could increased by98. 64%( compared with the base paperboard without any coating treatment).

Experimental Research on the Dynamic Energy Absorbing Capacity of the Honeycomb Paperboard Filled with Polyurethane

A kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results,the mechanical behaviors of the material under low velocity dynamic impact conditions were analyzed. It was shown that the absorbed energy of the composite material varies inversely with the void diameter. The absorbed energy of the composite material is 1- 2 times than that of honeycomb paperboard and polyurethane. The energy absorption efficiency of the composite material is better than those of honeycomb paperboard and polyurethane.

Bacteria in Indian Food Packaging Papers and Paperboards with Various Contents of Pulp Fiber

The food packaging industry generally uses papers and paperboards (PPBs) especially for disposable products. According to the Framework Regulation (EC) No. 1935/2004 of the European Union, no transfer of contamination should occur from food packaging material to the food items. The aim of this study was to determine the presence, numbers, source and different kinds of bacteria present in food packaging PPBs with various contents of pulp fiber. The samples were randomly collected from popular confectioners and fast food restaurants in Saharanpur, India. The results indicated the presence of bacteria in all the samples, ranging from 1.3 × 102 to 6.1 × 103 cfu/g. Most of the samples contained bacteria in more than the permitted concentration of 2.5 × 102 cfu/g as set by Food and Drug Administration (FDA). The detected bacteria were from genera Bacillacea, Staphylococcus and Pseudomonas. According to the FDA declaration, pathogenic bacteria such as B. cereus and S. aureus have been associated with food borne diseases (FBD). Some contaminants in food packaging PPBs were found to be B. subtilis and P. aeroginosa, which produce enzymes like peroxidases and lipoxygenases that are odor generating enzymes.

Levels of Selected Heavy Metals in Food Packaging Papers and Paperboards Used in India

In the present study, the varieties of papers and paperboards (PPBs) used in India for food packaging were qualitatively and quantitatively analyzed for the heavy metal contamination with the help of ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometry). Total 10 different types of food packaging PPBs were procured from local market and analyzed for 14 heavy metals (Al, As, B, Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, Te, Ti and V). Quantities of heavy metals in the samples were compared with permitted values published by the European Council. Heavy metals like Al, As, Ba, Cr, Co, Ni, Pb and V were observed in more than the permitted concentration in some of the samples. Heavy metals toxicity in food packaging material is a serious concern as the edible items get exposed to these metals and also generate volatile odorous compounds which considerably impact the quality of food and affect consumer's health.

Silica-Based Nanocoating Doped by Layered Double Hydroxides to Enhance the Paperboard Barrier Properties

Paperboard is an environment-friendly multi-layer material widely used for packaging applications. However, for food packaging paperboard lacks essential barrier properties towards oxygen and water vapor. Conventional solutions to enhance these barrier properties (e.g. paperboard film coating with synthetic polymers) require special manufacturing facilities and difficult the end-of-life disposal and recycling of the paperboard. Paperboard coating with silica-based formulations is an eco-friendly alternative hereby disclosed. Silica-nanocoatings were prepared by sol-gel synthesis, with or without the addition of Zn(2)-Al-NO3 layered double hydroxides (LDHs), and applied on the surface (ca 2 g/m2) of industrial paperboard samples by a roll-to-roll technique. The physicochemical features of silica-nanocoatings were studied by FTIR-ATR, SEM/EDS, XRD analysis and surface energy measurements. The barrier properties of uncoated and silica-coated paperboard were accessed by water vapor transmission rate (WVTR) and oxygen permeability (Jo2) measurements. The best barrier results were obtained for paperboard coated with a mixture of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), with and without the incorporation of LDHs.

STUDY ON THE BIODEGRADATION OF CELLULOSE FIBER/BASALTIC FIBER COMPOSITE PAPERBOARD

Influence factors on the biodegradation of cellulose fiber composite paperboard were studied experimentally and explained theoretically. The results show that the inorganic salts as nutriment added in the soil lixivium, the ratio of C/N, the temperature for biodegradation and content of basaltic fibers in the composite paperboard are the main influence factors.

竹木微漂长纤维浆用于牛卡纸的生产中试

福建青山纸业立足本地竹木资源,利用生产系统中间歇蒸煮制浆,多层牛卡纸机抄纸,积极响应国家以竹代塑的生态环保理念,探索性生产竹木微漂牛卡纸。

蜂窝纸板振动传递特性关系的研究

为快速获取蜂窝纸板振动传递特性曲线的峰值数据,开展振动仿真实验;研究蜂窝纸板孔径、砝码与蜂窝纸板的接触面积、纸板厚度、砝码质量4个变量与振动传递率及其对应频率的关系;通过多项式拟合得到变量-频率和变量-振动传递率2个关系式,并评估所得关系式的预测准确性。结果表明,用于表示关系式拟合精度的R2分别为0.997和0.991,表示其预测精度的R2分别为0.996和0.969;R2均接近1,说明所得关系式的拟合、预测准确度均较高。对11种优化算法的拟合结果进行对比,发现麦夸特法+通用全局优化法的拟合精度最高。本课题所提出的方法可在一定环境条件下、设定的参数范围内进行振动传递率-频率曲线关键数据的有效预测,可以降低实操中的实验工作量。

中国纸及纸板消费影响因素与需求预测

基于2005—2020年相关数据,利用灰色关联分析研究影响中国纸及纸板和各纸种消费的因素,综合运用多元回归分析(multiple regression analysis,MRA)模型、差分自回归移动平均模型(autoregressive integrated moving average model,ARIMA模型)和灰色模型GM(1,1)对中国纸及纸板和各纸种进行需求预测。研究发现,中国纸及纸板消费受到多方面因素的影响,各纸种影响因素存在较大差异;2025年前中国纸及纸板需求年均增长率为2.15%~2.76%,但各纸种需求年均增长率差别较大。企业应及时关注所生产纸种主要影响因素的变化,根据纸及纸板和各纸种消费需求发展趋势,及时调整产品结构,适应消费需求的变化。

绝缘纸板介电与击穿性能匹配目标下的制备参数优化方法

交流电压下油纸复合绝缘中纸板的介电常数越低整体的耐压水平越高。不同制备工艺参数会直接影响绝缘纸板的介电常数和击穿场强,但目前关于打浆、热压等工艺的制备参数与介电、击穿性能之间缺乏协同优化。本文从打浆时间、打浆压力、热压时间、热压压力、热压温度等工艺入手,研究制备工艺对1mm高密度针叶木绝缘纸板性能的影响和权重;通过权重大小改变不同工艺参数的组合方式,进而寻求最佳工艺,使得降低油浸纸板介电常数的同时保持其击穿性能不下降。利用电声脉冲法测量油浸纸板内部空间电荷,用表面电位衰减法测量油浸纸板表面陷阱参数,揭示了工艺和表面结构对性能的影响机理。研究结果表明:对于介电和击穿性能相匹配这一目标而言,高密度针叶木绝缘纸板的最佳工艺为:打浆参数取3 kg、60 min,热压参数取160℃、50 min、15 MPa。因为高打浆压力使得纤维分丝帚化程度更高,进而限制电荷在纤维间传输,同时减小油隙,提高油浸纸板击穿场强;适当的热压温度、热压压力、表面结构可以降低界面、表面陷阱密度和陷阱深浅,使得电荷分布更加均匀,从而降低界面极化和介电常数,为绝缘纸板制备和性能调控提供指导。

热老化过程中油浸纸板电阻率影响因素研究

在运变压器内油浸纸在高温作用下逐渐发生老化,其电阻率会随老化程度的加深而变化。为了更加全面地了解老化过程中除水分外影响油浸纸电阻率的各种因素,首先对未浸油纸板在真空下进行加速热老化,制作出不同聚合度的样品,并严格控制样品含水量,在真空环境下对其进行电阻率测试,以此探究未浸油纸板聚合度对其电阻率的影响;之后将不同聚合度的纸板分别浸入不同电阻率的变压器矿物油中,探究变压器油电阻率对油浸纸板电阻率的影响;最后对浸油后的纸板在氮气条件下进行加速热老化,观察老化后油浸纸板电阻率的变化。结果表明:单纯的纸板老化会使得其电阻率上升,油浸之后部分抵消了纸板单独老化时电阻率上升的趋势,但不同电阻率的油样对油浸纸板电阻率没有明显的影响规律,而在含水量相近的条件下,油浸纸板电阻率随着老化产物的增多而下降明显。老化过程中油浸纸板电阻率的下降,是由于纸板和油老化后产生的水分、酸、糠醛等极性物质导致的,且油浸纸板聚合度与其电阻率之间存在量化关系。

蜂窝纸板弯曲破坏模式和机理研究

基于蜂窝纸板的结构和受力情况,对蜂窝纸板进行三点弯曲实验,分析纸蜂窝夹层结构的弯曲破坏模式和弯曲破坏过程,探究纸蜂窝夹层结构弯曲变形机理。结果表明:蜂窝纸板的弯曲破坏模式主要有面板屈曲褶皱和局部塌陷两种;蜂窝纸板的弯曲破坏过程分为5个阶段;蜂窝纸板的弯曲破坏模式与面板屈曲、蜂窝胞元壁受压形成塑性铰以及蜂窝胞元壁向中间挤压靠近有关。

基于多折叠单元理论的蜂窝纸板面外压缩数值模拟

通过原纸拉伸试验获取蜂窝纸板的材料参数,建立蜂窝纸板的有限元简化模型(Y单元模型),采用有限元方法对该模型进行准静态加速压缩模拟,并与蜂窝纸板的面外准静态压缩试验结果进行对比;采用该模拟方法研究蜂窝孔边长、纸板厚度和胞壁厚度对Y单元折叠模式的影响。结果表明:Y单元模型经准静态加速压缩模拟得到的形貌与试验结果相吻合,压缩应力-应变曲线中平台应力的模拟结果与试验结果的相对误差为3.87%,验证了该模型的可靠性;不同规格的Y单元模型在压缩后共出现3种折叠模式,蜂窝孔边长和纸板厚度是影响Y单元折叠模式的2个关键因素。1/2蜂窝孔边长与一次折叠褶皱波长的比值会影响Y单元的一次折叠模式,而双层胞壁与单层胞壁的厚度差是导致多折叠模式发生的主要原因。

基于蜂窝纸板的系留平台缓冲分析与试验

为保证系留气球平台在空投着陆中的安全,必须对其中的压力气瓶进行缓冲分析与实验。文章采用蜂窝纸板作为气瓶缓冲材料,采用LS-DYNA软件,并依据蜂窝纸板实际参数处理材料模型,仿真分析了在不同蜂窝纸板厚度、不同跌落速度和不同着陆姿态下的缓冲过程。根据仿真结果,设计了蜂窝纸板缓冲结构和加速度检测模块,采用吊车起吊跌落进行了实验验证。仿真分析和实验结果均表明,蜂窝纸板厚度为500mm,跌落速度低于10m/s时,气瓶缓冲后加速度低于20gn,可满足空投着陆应用要求。文章基于LS-DYNA的蜂窝纸板缓冲有限元分析是可行的,研究结果对于气瓶类装备的着陆缓冲结构设计有参考价值。

纸板机胶黏物问题处理的实践

主要对三叠网纸机生产箱纸板的胶黏物产生进行分析,列举出不同部位产生胶黏物引起的纸病现象,采取相应的改进措施提高了纸机运行率和减少了纸病出现的几率,对箱纸板抄造过程中胶黏物的控制有一定的参考意义。

炭块自动夹纸板系统的设计与应用

研发了一种新型炭块自动夹纸板系统,替代人工在相邻两炭块之间投放夹纸板.该系统由取纸板机构、升降机构、夹持机构、横移机构、门架、夹纸板筐及控制系统等组成.实测结果表明,该系统夹纸板漏夹、偏夹率≤1%,夹纸板速率≥48张/小时,具有结构紧凑、运行平稳、安全可靠等优点,完全能够满足用户使用工况要求.

顶空固相微萃取⁃气相色谱质谱快速测定聚酰胺环氧氯丙烷湿强剂中氯丙醇含量

建立了快速测定聚酰胺环氧氯丙烷(PAE)湿强剂中1,3-二氯-2-丙醇和3-氯-1,2-丙二醇的顶空固相微萃取-气相色谱质谱方法。采用二乙烯基苯/碳宽范围/聚二甲基硅氧烷(DVB-CWR-PDMS)萃取头,取样量2 mL、萃取温度60℃、萃取时间30 min、加热器转速300 r/min、解析时间2 min、NaCl加入量1.2 g,对湿强剂氯丙醇进行萃取,经DB-WAX色谱柱(30 m×0.25 mm×0.25μm)分离后,质谱选择离子监测模式检测,外标法定量。PAE湿强剂中1,3-二氯-2-丙醇和3-氯-1,2-丙二醇线性范围分别为0.01~0.1 mg/L和1.0~10 mg/L、相关系数均大于0.999、加标回收率范围分别为95%~110%和96%~113%、检出限分别为0.0001 mg/L和0.1 mg/L。该方法简单、准确、检出限低、无需使用衍生剂,大幅缩短前处理时间和成本,适用于PAE湿强剂样品中氯丙醇的快速测定。

瓦楞纸板生产线辊子力学性能有限元分析

为明确3.3 m大幅宽新型高速瓦楞纸板生产线单机设备辊子采用铝辊设计的可行性,选取受力最恶劣的辊子作为研究对象,将钢辊作为对比,应用Mechanical软件和LS-DYNA软件对辊子进行力学性能分析。分别建立辊子静力学和显式动力学有限元模型,计算辊子静扰度、模态频率、动扰度。通过计算可知,铝辊在车速420 m/min以内运行,强度安全。通过分析,提出加大壁厚和设计为中凹辊的优化方向,中凹值可参考辊子径向变形量与原纸张力间的关系曲线获得。