低毒脲醛树脂胶粘剂在E1级胶合板中的应用

在低毒脲醛树脂胶粘剂合成过程中加入淀粉或氧化淀粉，能有效地改善胶合板板坯的预压性能和胶合板的胶接强度.当淀粉、氧化淀粉加入量为合成低毒脲醛树脂胶粘剂所用尿素量的30%～40%时，达到较好的使用效果.通过在低毒脲醛树脂胶粘剂调制过程中加入低成本API对低毒脲醛树脂胶粘剂进行改性，亦能改善胶合板板坯的预压性能和胶合板的胶接强度.试验表明，随着低成本API加入量的增加，胶合板的预压性能、胶接强度都有明显提高.考虑成本原因，低成本API的加入量为3%～10%即可达到较好的使用效果.改性低毒脲醛树脂胶粘剂能适应多层胶合板的生产。     

玉米淀粉在木材胶粘剂中的应用

通过对玉米淀粉进行适当的处理,可以以其为主要原料生产木材用无臭胶粘剂;在脲醛树脂调胶或合成过程中加入玉米淀粉,可以有效地改善脲醛树脂胶粘剂的综合性能,使其具有更好的预压性能和胶合性能;玉米淀粉可以加快聚醋酸乙烯酯乳液的固化速度;用玉米淀粉对API进行改性,能生产出适合胶合板等生产的低成本API胶粘剂。     

玉米淀粉在木材胶粘剂中的应用

通过对玉米淀粉进行适当的处理，可以以其为主要原料生产木材用无臭胶粘剂；在脲醛树脂调胶或合成过程中加入玉米淀粉，可以有效地改善脲醛树脂胶粘剂的综合性能，使其具有更好的预压性能和胶合性能；玉米淀粉可以加快聚醛酸乙烯酯乳液的固化速度；用玉米淀粉对API进行改性，能生产出适合胶合板等生产的低成本API胶粘剂。     

胶乳在改性脲醛树脂胶粘剂中的应用

在人造板生产中,乳液胶粘剂主要应用于人造板贴面加工.本研究主要利用胶乳对脲醛树脂进行改性,同时在脲醛树脂合成过程中加入一定数量的氧化淀粉,进一步提高改性脲醛树脂的综合性能.生产的低摩尔比胶合板用改性脲醛树脂胶粘剂具有游离甲醛含量低,预压性能好,生产工艺简单等特点,制作的胶合板胶合强度和甲醛释放量均满足国家标准要求.     

胶乳在改性脲醛树脂胶粘剂中的应用

在人造板生产中，乳液胶粘剂主要应用于人造板贴面加工。本研究主要利用胶乳对脲醛树脂进行改性，同时在脲醛树脂合成过程中加入一定数量的氧化淀粉，进一步提高改性脲醛树脂的综合性能：生产的低摩尔比胶合板用改性脲醛树脂胶粘剂具有游离甲醛含量低，预压性能好，生产工艺简单等特点，制作的胶合板胶合强度和甲醛释放量均满足国家标准要求。     

纳米二氧化钛改性脲醛树脂胶黏剂研究

以锐钛型纳米二氧化钛为改性剂,对脲醛树脂胶黏剂进行改性研究,以期得到低毒脲醛树脂胶黏剂的制备工艺技术。首先使用无机复合修饰的合成路线,通过改变锐钛型纳米二氧化钛的添加量、纳米二氧化钛的添加时机和甲醛与尿素(F/U)的摩尔比进行实验,研究纳米二氧化钛对脲醛树脂胶黏剂产品性能的影响。结果表明:当甲醛与尿素(F/U)的摩尔比为1.3,纳米二氧化钛在树脂反应后期加入,且加入量为尿素质量的1%,合成出的脲醛树脂性能较好,湿状胶合强度达到0.8MPa,游离甲醛含量为0.49%。该胶黏剂符合国家标准GB14732-93中对水基缩甲醛类胶黏剂甲醛的限量规定小于0.5%的要求。     

木素粉剂用量对胶合板性能的影响

探讨了造纸废液提取物——木素粉剂作为脲醛树脂胶改性剂的可行性,分析了木素粉剂不同用量对胶合板胶合强度、浸渍剥离性能、吸水厚度膨胀率及甲醛释放量的影响。研究结果表明:木素粉剂作为脲醛树脂胶的改性剂可有效捕捉其游离甲醛;木素粉剂用量小于15%时,改性脲醛树脂胶胶合板的理化性能较好。     

低游离甲醛脲醛树脂胶粘剂的合成研究

对低游离甲醛脲醛树脂胶粘剂的合成条件进行了探索.通过降低甲醛与尿素的摩尔比、选取合适的三聚氰胺加入量和加入时间、优化尿素分批加入比例,合成了一种低游离甲醛含量的脲醛树脂胶粘剂.结果表明,控制甲醛/尿素摩尔比为1.1,三聚氰胺加入量占尿素质量2%并在中期加入,尿素分批加入比例为60:15:25时合成的脲醛树脂游离甲醛含量在0.1%以下.该胶粘剂生产成本低,合成时间短,树脂综合性能及其胶合板的胶合性能良好.     

胶原蛋白改性脲醛树脂胶黏剂的研究

以铬鞣革屑中提取的蛋白质对脲醛树脂进行改性,目的主要是为了提高,脲醛树脂的胶接强度、降低其生产成本及其游离甲醛含量。试验表明:当蛋白质提取液与脲醛树脂1∶1混合时,可以使其胶接强度达到最大值6.95MPa,而当蛋白质提取液的加入量为脲醛树脂的1.5倍时,游离甲醛含量为0.053%,远低于国家标准的要求(0.3%)和纯脲醛树脂中游离甲醛的含量(0.385%),而此时胶接强度也达到了国家标准的要求(1.9MPa)。     

氧化淀粉改性脲醛树脂的应用

脲醛树脂中加入其质量的15%的氧化淀粉共混反应,制备成氧化淀粉改性脲醛树脂。该样品为白色膏状物质,含固量为30.55%,游离甲醛值为0.07%,贮存稳定。用其复鞣填充的坯革撕裂强度为2.48 N/mm,拉伸强度为14.4 0 MPa,断裂伸长率为161.06%,且饱满、富有弹性、黑色调饱满及粒面平整;耐热及耐折性能优良。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status