纸用透明剂

纸用透明剂是一种新型的纸张功能改性化学品。本文简述了纸张的光学性能和纸用透明剂的作用机理；介绍了纸用透明剂的种类和部分产品，并针对纸用透明剂的使用方法。列举了一些实例，意在促进我国纸用透明剂的生产和使用。     

单色机套印四色产品关键问题把握

用单色机套印四色产品时,会出现各种个样的生产故障和问题。笔者以光华单色机套印四色产品为例,来对这些问题加以认识和总结。一般情况下,做好以下几个方面的工作,有利于保证产品的质量。1上纸1)保证纸张良好的物性纸张透气性和机械性能等印刷的适性,会直接影响到输纸的顺畅与否。故而装纸上纸之前,要通过理纸,把纸张预处理到比较平整的状态下。特别     

基于视频分析的造纸现场监测系统设计

目前,人们日常生活水平和质量在不断提高,因此对纸产品的需求不断增长,对纸张的质量要求越来越高。在人工对纸张质量检测上,成本较高、效率变低、容易漏检等问题,不能够提高造纸工业的发展。因此通过视频采集设备、纸张质量检测设备、客户端和服务器等,把断纸检测设备中检测到的数据和视频采集的数据进行分析,实现了对断纸事故的准确检测和定位,提高纸张生产效率和保证纸张的质量。     

未涂布纸的匀度对印刷适性的影响

印刷斑点的形成取决于纸张、油墨和印刷机的特性及其在印刷过程中的相互作用.纸张的微观结构、孔径、细小纤维分布、表面粗糙度和涂层结构等性能会影响印刷适性.一些研究者已经阐述了造成涂布纸和新闻纸的印刷斑点的原因,但是对未涂布文化用纸胶版印刷适性的报道很少,Kajanto、Shallhorn和Heintze考察了未涂布不含磨木浆纸的胶版印刷适性,并推断纸张的匀度与视觉上的印刷质量有高度相关性,本实验定量分析了在Heidelberg胶版印刷机上印刷的未涂布高级文化用纸的纸张成形质量对印刷适性的特定影响,用仪器测定了纸张匀度和印刷斑点.     

改性壳聚糖类表面施胶剂在轻型胶版纸中的应用

为了满足纸张生产的需要,抄纸过程中需要在纸张表面使用一些合成施胶剂来提高纸张的表面强度和适印性能。目前,造纸生产过程中通常使用的纸张表面施胶剂为改性的烷基烯酮二聚体（AKD）或苯乙烯丙烯酸丁酯共聚物等产品,其原料多为资源紧缺、价格昂贵的石油化工产品．而且多为不可生物降解．严重影响生产一线职工的身体健康,并对环境易造成污染。     

Atlantic Packaging Products公司重启Whitby纸厂

Atlantic Packaging Products公司宣布将于2013年3月重新启动地处加拿大安大略省的Whitby纸厂。Atlantic声称,这家原新闻纸厂经过技术升级,可生产100%可再生低定量纸,用于制作高性能瓦楞包装纸产品。公司董事长Dave Boles表示:"在北美地区,低定量纸主要关注纸张定量,而对纸张强     

纸张堆版原因与排除

在胶印过程中由于纸张的施胶孔隙结构、平滑度、吸收性、黏弹性等,纸张在造纸过程中填料、胶料、色料颗粒粗糙,纸张的外观质量尘埃、斑点、纤维团、砂粒等方面质量差,经常会产生堆版的故障。堆版的原因有许多,本文主要谈谈:纸张脱毛、纸张脱粉、橡皮布上堆纸毛、纸灰。纸张堆版的原因不同,解决方法也有所不同。胶印过程中出现纸毛堆版的故障,主要是纸张表面纤维结构疏松引起的纸张脱毛造成的,这种现象主要是印刷质量较差的纸张,其故障表现为印迹墨色表面为乱纸屑似的花白现象,纸毛脱落引起印版、橡皮布表面沾满纸毛,严重时每印刷1000张就需…     

刍制晾纸机解决纸张起皱问题

纸张起皱是胶印过程中经常遇到的问题,其中环境温湿度的变化是造成纸张起皱的重要原因之。为了解决纸张起皱问题,就需要进行晾纸。常用的晾纸方法是自然晾纸法,将库存纸张在使用前事先裁切好放到生产车间,让纸张的含水量与生产车间的湿度逐渐达到一致,这样在印刷时纸张就不易起皱了。     

兆日科技“纸纹防伪技术”通过技术评审

正本刊讯据证券时报网2014年7月1日报道:"纸纹防伪技术及产品系统"是兆日科技公司IPO募投项目之一的"金融票据防克隆产品研发及产业化项目"。其基本原理是,任何纸张都具有自然、随机的植物纤维分布("纸纹"),任何纸张的纸纹是唯一、稳定和不可复制的,纸纹防伪技术利用专门研制的具有纸纹传感器的纸纹识别装置、模式识别和计算机网络技术,可以获取、存储和比对纸纹,通过将待测纸张的纸纹信息与存储在网络中该纸张的原始纸纹信息进行比对,从而可判断该纸张的真伪。2014年3月,经过近两年的产品化研发,产品和技术基本成熟,公司正式向中国防伪技术协会、国     

遗传模拟退火算法的纸张表面缺陷智能化检测

造纸工业的自动化生成过程中,不可避免的会使纸张出现各种表面缺陷,缺陷的存在严重影响到纸张的质量和纸产品生产的效率,因此对于纸张表面缺陷的智能化检测逐渐成为纸张生产领域研究热点。设计了一种基于遗传模拟退火算法的纸张表面缺陷检测与分类算法,首先对造纸厂生产线上工业相机采集的纸张图像进行预处理、纸张缺陷区域检测与提取,重点设计了遗传模拟退火算法的缺陷检测分类方案,经验证,所设计的遗传模拟退火算法得到的模型能够对边裂、黑斑、孔洞、褶皱、亮斑和划痕这六类纸病精确的辨识。缺陷的辨识率大于99.7%,完全满足纸张表面质量的检测要求。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.