胶黏物在废纸回用过程中的循环适应性分析

美国邮政总局(USPS)"环境友好型压敏胶邮票"项目研究了压敏胶在常规废纸循环过程中的去除特性,并由此制定了检测胶黏剂循环适应性(RCA)的行业标准,为衡量不同种类的胶黏剂是否适官进人废纸回用系统以及为生产厂商生产具有良好循环适应性的胶黏剂产品提供了依据.参考该标准中的实验条件和检测方法,对不干胶纸所带的3种压敏胶(PSAs)在废纸回用过程中的去除特性,即循环适应性.进行了实验分析,比较了胶黏物在不同处理阶段的分散特点和去除差异,在此基础上,探讨了碎浆、筛选和浮选3个处理单元在胶黏物去除过程中的不同作用和天联影响,并结合RCA标准.对该胶黏剂的循环适应性作了分析评定.     

酶在废纸回用生产中的应用研究及进展

随着我国经济从高速发展过渡到高质量发展阶段,以及国家对洋垃圾进口限令的颁布实施,导致废纸价格节节攀升,废纸的高效集约利用显得尤为重要。本文介绍了各种生物酶在废纸回用生产中的相关应用研究及进展,重点对其在废纸脱墨、胶黏物控制、浆料漂白、打浆及废水处理等方面的应用研究进展作了阐述,并就其在废纸回用领域应用时存在的主要问题和应用前景进行了讨论和展望。     

提高浆料筛选质量的压力筛

正申请公布号:CN 111962323 A发明人:王加平申请人:玖龙纸业(天津)有限公司随着造纸行业的快速发展,国内废纸利用率在逐年提高,废纸的回用次数也在逐年上升,废纸的强度呈下降趋势。为了提高成纸强度,各个造纸厂使用干强剂、湿强剂、两性淀粉、施胶等化学助剂越来越多,而化学品的大量使用给废纸的回用带来越来越多的难题,特别是两性淀粉、施胶、施蜡等胶黏物多的助剂,影响纸机的运行和成纸外观质量。利用压力筛去除胶黏物是一种高效的设备,通过纤维与胶黏物尺寸、物理特性的不同,分离浆料中的胶黏物,提高浆料质量。但是该方法存在以下问题:(1)随着废纸中胶黏物的增加,普通压力筛的胶黏物去除率偏小,满足不了工艺的需求;(2)纸机向着高幅宽、高车速发展,提升质量的同时,如何不影响纸机产量。     

旧报纸脱墨浆生产过程中的大胶黏物特性研究

以现代化大型脱墨浆生产线为对象,采用Pulmac MasterScreen胶黏物筛分仪对取自生产线不同部位的废纸脱墨浆样进行筛分处理,以获得胶黏物试样,然后采用Verity IA MasterScreen图像分析软件检测了大胶黏物的数量、面积和含量,讨论了在废纸脱墨制浆过程中大胶黏物的存在状况及不同操作单元对大胶黏物的去除作用。结果表明,大部分的大胶黏物尺寸为0.01～0.10 mm2;从废纸碎解成浆到纸机前,90%以上的大胶黏物可通过筛选净化除去;粗筛选和低浓除渣、精筛选分别可以去除进浆中大约45%、31%的大胶黏物;热分散处理可以显著减小大胶黏物的尺寸。     

废纸回用过程胶黏剂控制技术的研究进展

对胶黏物的来源、种类、特性和胶黏物常规的去除方法作了分析,特别是对废纸胶黏物处理技术新进展作了重点论述,其中包括:改进的机械物理方法、改进的化学方法、改进生物方法及其他方法等,并就胶黏物问题提出了新的研究方向。     

信息

旧报纸脱墨浆生产过程中胶黏物的特性本刊讯由山东轻工业学院李超等人以现代化大型脱墨浆生产线为对象,采用Pulmac Master Screen胶黏物筛分仪对取自生产线不同部位的废纸脱墨浆样进行筛分处理,以获得胶黏物试样,然后采用Verity IA Master Screen图像分析软件检测了大胶黏物的数量、面积和含量,探讨了在废纸脱墨制浆过程中大胶黏物的存在状况及不同操作单元对大胶黏物的去除作用。     

OCC回用过程中胶黏物的定量分析及浮选控制

以废纸为原料生产挂面纸板会给造纸厂带来许多问题.如果不进行适当控制,就会引起产品质量下降,并影响纸机正常运行.为解决废纸造纸带来的诸多问题,科研工作者进行了广泛的研究并开发出了许多新技术方法,如纤维分级、磨浆前用酶处理回收纤维、表面施胶和Condebelt干燥等.近来,许多造纸生产者已经意识到了废纸回用中控制胶黏物的重要性.因此,有必要确立胶黏物定量分析的标准方法,以此来评价胶黏物对产品质量和纸机运行状况的影响,并测定造纸过程中不同部位的胶黏物含量.     

浅层气浮处理废纸造纸网下白水

<正>废纸中的胶黏物,主要来自各种添加剂中的胶黏剂~([1])。常规的胶黏物去除方法主要包括三大类:机械物理方法,化学方法和生物方法~([2])。机械物理方法主要应用在制浆工段,如筛选、热分散处理等。废纸的脱墨常用浮选法,对胶黏物,尤其是对粒径在     

福伊特筛选系统改造助力客户提质降耗

<正>在以废纸为原料进行制浆的过程中,分级筛选的主要目的是去除胶黏物,提高浆料洁净度。长期以来,胶黏物问题一直困扰着以废纸为原料的纸厂。胶黏物沉积并黏附于纸机的成形网、毛毯、压辊、吸水箱、烘缸表面及管道中,造成糊网、毛毯孔眼堵塞、黏烘缸等问题,形成胶黏物"障碍"。这会造成纸幅脱水不均,并引发多种纸病,严重时会造成     

浮选设备在OCC制浆系统杂质去除中的应用

介绍了在废瓦楞箱纸板(OCC)制浆生产过程中增加浮选设备,用于去除OCC浆料中的胶黏物等杂质,以减轻胶黏物等杂质对后续生产运行及成品纸张质量的负面影响。结果表明:OCC浆料经浮选后胶黏物去除率约为39%,灰分去除率约为34%;精筛处理后浮渣的胶黏物去除率约为71%,可以进行纤维回收。说明本制浆系统改造对OCC浆料中胶黏物和灰分都有较好的去除效果,是解决废纸制浆杂质去除问题的有效途径。     

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.