对低游离甲醛人造板生产中几个问题的探讨

讨论了低游离甲醛胶粘剂和人造板生产中关于预压性能、甲醛捕捉剂、游离甲醛与尿素的关系、固体含量与树脂含量的关系。固化剂的选择、树种和某些生产工艺因素对人造板中甲醛释放量的影响等热点问题。     

甲醛清除膜清除人造板和家具中游离甲醛的试验研究

针对目前国内室内游离甲醛浓度严重超标的现状，研制开发了一种清除游离甲醛的新材料——甲醛清除膜。在开发过程中，探讨了其清除人造板游离甲醛的持续性，其载药量、放置方法与用量以及人造板的种类等与清除游离甲醛效果的关系，并进行了清除家具中游离甲醛的试验。     

甲醛清除膜清除人造板和家具中游离甲醛的试验研究

针对目前国内室内游离甲醛浓度严重超标的现状,研制开发了一种清除游离甲醛的新材料——甲醛清除膜。在开发过程中,探讨了其清除人造板游离甲醛的持续性,其载药量、放置方法与用量以及人造板的种类等与清除游离甲醛效果的关系,并进行了清除家具中游离甲醛的试验。     

降低人造板中脲醛树脂游离甲醛含量的几种方法

脲醋树脂胶粘剂由于存在较多的游离甲醛,而阻碍其应用。本文提出了降低人造板中游离甲醛含量的几种方法。     

低毒脲醛树脂胶贮存期的研究

脲醛树脂胶是人造板及一些建筑材料生产中最常用的一种胶粘剂，具有较高的胶接强度、耐冷水性能和适当的耐热水性能等优良性能。但是。树脂中存在有害于人体健康的游离甲醛。近些年来科研工作者在探索和研究有效的生产方法以降低脲醛树脂胶中游离甲醛含量。然而。有些方法在降低脲醛树脂胶游离甲醛含量的同时却带来了脲醛树脂胶的贮存期缩短的问题。给人造板生产带来不便。本文介绍了几种生产低毒长贮存期脲醛树脂的方法，供同行参考。     

国外人造板甲醛释放的测定方法

介绍人造板中游离甲醛的来源和危害性,并对国外人造板甲醛释放量的几种测定方法进行了研究分析。     

论人造板游离甲醛释放量及检测

论人造板游离甲醛释放量及检测中南林学院郑睿贤编者按本文根据科学的试验数据，对现行标准中游离甲醛释放量的测定方法提出质疑，如何科学地制定游离甲醛释放量测定方法，关系到我国人造板工业的发展。因此，本文提出的观点值得标准制定部门研究考虑。Ｅｄｉｔｏｒｉａｌ...     

人造板产品中的甲醛对室内环境的影响

介绍了我国人造板产品的现状。分析了甲醛的危害性、带来的后果和产生的原因,并简单阐述了游离甲醛的测定方法的和避免甲醛污染的办法。     

浅议低游离甲醛人造板中游离甲醛的测定

探讨低游离甲醛人造板的游离甲醛测定方法,对如何有效降低测定误差及提高其精确度的各种影响因素进行分析。     

慎待家具的游离甲醛问题

经销与使用家具，甚至生产家具都有一项应知应会的知识至关重要——游离甲醛问题。甲醛与游离甲醛是两个概念，须弄清楚后方可从容对待。 甲醛（ＣＨ２Ｏ），是一种化学物质。在人们日常生活的环境温度下为气体，虽无颜色但有强烈刺激性；通常情况下将甲醛在水中保存，形成甲醛水溶液，即福尔马林。甲醛的因、液、气三态均有不断的挥发性，即游离甲醛。游离甲醛在常温下每时每刻都在从发生源处外逸着。甲醛是目前家具主要用材原料——人造板的主要原料之一。甲醛与尿素经缩合反应后，生成脲醛树酯，人造板材则以脲醛树酯做为生产人造板的粘…     

Volatile organic compounds and formaldehyde in nature, wood and wood based panels

The emission of terpene compounds from vegetation is subject to seasonal and diurnal variations. Due to oxidation of terpene compounds simple aldehydes like formaldehyde can be formed. Insofar formaldehyde is an ubiquitous chemical. Due to its high reactivity it has a short half-life time. Wood and wood-based panels emit a low, but still detectable, amount of formaldehyde. The emission depends on exogenic (temperature, relative humidity, air exchange level) and endogenic (wood species, binder level, binder type, production conditions, etc.) factors. With the aging of boards formaldehyde release declines tremendously to reach very low level. Nevertheless, with low fuming binders wood-based panels with formaldehyde emission close to that of untreated wood can be prepared. Non-formaldehyde volatile organic compounds (VOCs) can be released from wood and wood-based panels. The emission rate depends on the wood species as well as on the boundary conditions (drying, storage, etc.). In the case of wood-based panels it depends also on the production factors as well as on the storage conditions. Methods to assess VOCs have been developed and regulations regarding the limits of emission values are under way.     

Lignin-based wood panel adhesives without formaldehyde

Lignin-based wood adhesives prepared without formaldehyde substituted by non-volatile non-toxic aldehyde, namely glyoxal, were prepared and tested for application to wood panels such as particleboard. The adhesives yielded good IB strength results of the panels, enough to comfortably pass relevant international standard specifications for exterior-grade panels. The adhesives also showed sufficient reactivity to yield panels in press times comparable to those of formaldehyde-based commercial adhesives.     

Utilization of bark flours as additive in plywood manufacturing

Increasing demand for wood based panel products and shortage of wood as raw material have triggered many efforts to utilize residues generated annually by the forest industries including a large portion of bark in panel production. In this study, the effects of using bark flours as additives obtained from different wood species (walnut, chestnut, fir and spruce), having much polyphenol content, on some physical and mechanical properties and formaldehyde emission of plywood panels were examined. Wheat flour, which has been used widely as additive in plywood manufacturing, served as control. Plane tree (Platanus orientalis) logs were obtained for veneer manufacturing. Urea formaldehyde (UF) resin with 55 % solids content was used as adhesive. The bonding shear strength, bending strength, modulus of elasticity (MOE), density, equilibrium moisture content and formaldehyde emission of plywood panels were determined according to related standards. It was found that the use of flours obtained from the barks of chestnut and fir trees in the glue mixture decreased the formaldehyde emission of panels. The bonding strength values of the test panels made using the glue mixture including the flour of walnut and spruce barks as additive were lower than those of the panels with adhesive containing the flour of fir and chestnut barks. The panels manufactured with adhesives including the flour of fir bark gave the highest bending strength and modulus of elasticity values.     

Macro- and microtechnological studies on beechwood panels bonded with Pinus brutia bark tannin

The suitability of hot water extracted tannins from the bark of Pinus brutia from Turkey as a binder either alone or in combination with phenol formaldehyde was examined. Using formaldehyde-hydrochloric acid about 77% of the active phenolic components could be precipitated. Because of the high molecular weights of the polyphenols only small amounts of formaldehyde were necessary for a complete curing. On the basis of the tannin along with a hardener, such as paraformaldehyde or hexamethylenetetramine, boiling-water-resistant gluing of beechwood panels was obtained (DIN 53254, DIN 68602). Electron microscopical and microanalytical studies of such tannin-bonded panels showed the localization of the adhesive, penetration of the adhesive into the wood cells as well as the interaction between the tannin adhesive and the wood cell walls.     

Hydroxymethyl furfural-modified urea–formaldehyde resin: synthesis and properties

Considering the importance of urea–formaldehyde (UF) resins in the wood industry, this work reports on a new bio-based modification of UF resins. The use of 5-hydroxymethyl furfural (HMF) is motivated by the current concerns about the effects of formaldehyde on human health. UF and urea–HMF–formaldehyde (UHF) resins were synthesized by an alkaline-acid method and characterized by FTIR, thermogravimetric analysis, and differential scanning calorimetry. The UHF, as a newly modified polymeric resin, was thermally characterized, and it was found that its thermo-stability and char yield was improved. In order to investigate the performance of the UHF, the preparation of particleboards with the UHF as adhesive, as well as its film formation ability have been studied. The UHF films formed on wood panels were uniform without any crack. Film formation ability of the UHF resin was improved due to the presence of more hydroxyl groups as well as furan rings of the HMF moieties resulting in more activated groups to be bonded by wood. Furthermore, formaldehyde release of the particleboards bonded by UHF was significantly lower than that of which bonded by the UF resin. Lab particleboards using the UHF resins showed higher modulus of rupture, modulus of elasticity, and internal bond compared to boards with UF resins, as well as lower water absorption and thickness swelling. Based on these results UHF resin can be considered as a possible candidate as adhesive for wood and wood based panels.     

Ionic liquids as enhancers of urea-glyoxal panel adhesives as substitutes for urea–formaldehyde resins

Acid ionic liquids are used as hardeners of urea-glyoxal adhesives to enhance them to a level sufficient enough for substituting urea–formaldehyde adhesives used in wood panels.     

Melamine–formaldehyde curing acceleration by TiO2-based silver-white pigments catalysis

European Journal of Wood and Wood Products - The preparation of melamine–formaldehyde (MF) resins for paper impregnation for wood panels laminating was found to be catalyzed by TiO2-mica...     

木材工业用胶黏剂低毒化研究进展

从合成树脂型胶黏剂的改进和生物质胶黏剂开发利用两方面,总结了木材工业用胶黏剂的低毒化研究进展,并提出根据我国国情着力发展生物质胶黏剂的建议。