非接触式涂布及其原纸

很多高速涂布工艺趋向于依赖先施涂过量的涂料,然后再用刮刀、计量棒或者气刀计量去除多余的涂料.标准施胶压榨涂布和计量施胶压榨涂布（MSP）二者明显例外.标准施胶压榨涂布的涂料上涂和计量同步进行,而计量施胶压榨涂布的涂料在上涂前进行计量.所有这些系统都依赖于上涂辊和纸张之间的直接接触,均为接触式涂布.上涂辊运行时靠在背辊上,二者的接触造成很大的水力“抽击”,导致纸幅表面相对其内部结构产生压缩.     

计量施胶压榨生产轻量涂布纸探讨

结合恒丰纸业生产经验,介绍采用计量施胶压榨设备生产轻量涂布纸的涂布工艺、涂料选择及设备调整等。     

涂布工艺对MFC涂布纸强度性能和阻隔性能的影响

探讨了棒涂和施胶压榨涂布对MFC涂布纸强度性能和阻隔性能的影响。棒涂只能进行单面涂布,而施胶压榨可进行双面涂布。MFC悬浮液含水量高,涂布次数相同时,棒涂的涂布量比施胶压榨涂布高,故水对棒涂纸样的影响更大,因此,棒涂对纸张强度性能的不利影响比施胶压榨涂布大。通过与水处理纸样对比可知,涂布纸强度性能的降低主要是由涂布时多次润湿和干燥引起的。由于涂料主要保留在纸张表面,故MFC对涂布纸强度性能的影响并不显著。在本实验所测定的阻隔性能当中,MFC涂层只对涂布纸透气度有显著影响。MFC可改善涂布纸防油性,但MFC网络结构中存在纳米级孔隙,即仅能减缓油料通过纸样的移动速率,而不能完全阻隔油料。     

计量施胶压榨技术的新发展

在 80年代中期,棒式和刮刀式计量施胶压榨开始替代传统的施胶压榨,其原因是棒式和刮刀式计量施胶压榨不受速度 (600～ 800 m/min)的限制。近年来,计量施胶压榨的用途明显扩大了,它不仅改进了施胶压榨,而且,也可以用于其他涂布和表面处理。表 1列举了可以用计量施胶压榨生产的各种纸。 　　当北美洲尚未普遍应用的时候,欧洲不含磨木浆高级纸的预涂已相当普遍地采用薄膜涂布了。计量施胶压榨有两项优点：可以使用高固含量涂料。大多数碳酸钙涂料用于预涂,将削弱涂后烘缸的干燥能力和提高速度。另一方面,可以用低价的颜料替代一些高…     

计量施胶压榨的发展

传统的双辊涂料堰施胶压榨在近一个世纪内一直是纸机标准组成单元,它不仅用于表面淀粉施胶,也用于颜料化预涂布和涂布。但它有许多局限性,胶料或涂料的拾起（Pickup)依赖于纸页的内施胶水平和水分含量。80年代早期开发了计量施胶压榨,它使用短驻留涂布头作为施胶装置,把湿的胶膜向辊表面转移。当今使用了几种类型施胶装置,包括短驻留涂布头、喷泉式和封闭式涂布头。计量元件的选择包括容积式沟纹棒（Volumetic grooved rods)、绕线式计量棒、压力控制刮刀和光滑棒。计量施胶压榨用于表面施胶,施胶量0．7－4．0g/m^2面,胶料固含量是5％－8％;用于颜料涂布时固含量是30％－65％,涂布量3－15g/m^2面。计量施胶压榨已成为一种重要的造纸工具。     

关于薄膜涂布的运行问题及涂布质量

薄膜压榨涂布又经常称为计量施胶压榨(MSP),由于具有投资省、生产效率高、可用成本较低的浆料生产高附加值的纸和纸板等优点,因此在涂布领域得到迅速发展。随着薄膜压榨涂布工艺的成熟,人们更加关注薄膜涂布纸质量的改进。用计量施胶压榨进行薄膜涂布主要是把一层很薄的涂料预涂在胶辊上(常称为转移辊),然后当两根辊相对转动时在压区处把这层薄膜转移至纸幅上。在转移压区处薄膜的分裂是十分重要的。因为它影响涂料转移率,也就是涂布量;同时会产生运行问题,如发生雾溅和生成桔子皮纹。薄膜分裂是取决于诸多因素的复杂现象如车速、脱水速度…     

用表面施胶压榨涂布生产轻涂胶印纸

用表面施胶压榨涂布生产轻涂胶印纸陈志寨福建省永安市造纸厂３６６０００关键词轻涂胶印纸，施胶压榨涂布轻涂技术应用于老企业带表面施胶的长网多缸造纸机上，投资低，见效快，产品又得到升级换代，我厂１５７５ｍｍ长网多缸纸机原生产普通双进纸，后采用施胶压榨涂布的...     

调整胶黏剂配比优化颜料性能

涂料成本由于地域的不同而有所差异,在某一地区具有质量和成本优势的涂料却不一定适合于另一地区.本文从纸张性能着手,通过采用两种不同窄粒径分布的碳酸钙与瓷土配比对低定量涂布纸(LWC)原纸进行计量施胶压榨(MSP)涂布和刮刀涂布以及采用最大固含量的涂料对不含磨木浆双面涂布纸(CWF)原纸进行面涂,研究了调整涂料中总胶黏剂用量以及优化颜料性能的可能性,目的在于给纸厂提供涂料配方,以提高纸张质量、降低成本.     

计量施胶压榨涂布中的涂层形成与液相渗透

在计量施胶压榨涂布中，涂料膜的厚度首先在涂布辊的表面进行调整，紧接着涂料膜与原纸在压区进行接触并在压区出口被转移到纸上。其涂布量主要取决于下面一些因素：涂料向原纸表面大孔隙内的渗透；涂料的脱水及其在原纸表面形成滤饼；发生在滤饼与涂布辊表面间的流动层中部的膜撕裂。     

改善薄膜压榨涂布的运行性能

薄膜压榨涂布的影响因素———从预计量到涂布及薄膜剥离。把薄膜压榨压区中涂料的脱水理论与在每面涂布量约１０ｇ／ｍ２、车速１０００ｍ／ｍｉｎ以上,含磨木浆和不含磨木浆条件下造纸的结果进行了比较。决定纸张运行性能和成纸表面质量的因素有：纸机参数、颜料和胶粘剂。造纸工作者的工作就是要在纸页的运行性能和表面质量之间这两个互相矛盾的要求中找到一个最佳方案。随着预计量薄膜施胶压榨用于表面施胶的巨大成功,使人们了解了使用颜料涂布纸机的潜能。市场上,机内整饰颜料化纸（ＭＦＰ）的质量优于薄膜涂布胶印纸（ＦＣＯ）和其…     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the