甲醛系木材胶粘剂

<正> 木材胶粘剂是一类籍助于表面附着将木材与木材或木材与其它材料胶合成一体的物质。通常包括酚醛树脂胶,脲醛树脂胶、三聚氰胺树脂胶、间苯二酚树脂胶、单宁胶、木素胶、多异氰酸酯胶、聚乙酸乙烯酯乳液以及植物蛋白胶、动物蛋白胶、淀粉胶等。其中最主要的是上列前三种,又合称三醛胶,它们都是由甲醛为主要原料合成的。这些胶粘剂,除了主体     

木材工业用酚醛树脂胶粘剂的快速固化研究

从酚醛树脂胶粘剂的配方改进、胶粘剂合成工艺改进、催化剂添加、胶粘剂调胶及人造板热压工艺改进等几个方面,综述了近几年来木材工业用酚醛树脂胶粘剂快速固化研究。     

木材用胶粘剂行业发展及市场现状

目前,木材用胶粘荆主要以“三醛”胶为主,占整个木材及人造板工业用胶粘剂的80%以上。脲醛树脂胶由于价格低廉,室内环境使用对其耐水、耐候性能要求不高,(主要用于生产刨花板、纤维板和胶合板),用三聚氰胺改性的脲醛树脂胶也有用于纸张浸渍的,其全部用量占“三醛”胶粘剂总量的80%以上;酚醛树脂胶,其胶合性能好,适合于室外环境使用,主要用于生产混凝土用胶     

专利介绍

铝板包铜箔、粘合表面装饰板、复合木的胶粘剂、粉状木材胶粘剂、环境友好的SBS喷胶、从废塑料制造防水胶粘剂……     

乳白胶木材胶粘剂的制备试验

本文介绍了木材粘合常用的两种合成树脂乳白胶和脲醛树脂的制备配方和工艺,叙述了用正交表进行乳白胶木材胶粘剂配方设计的试验情况。试验结果表明:(1)所述8个乳白胶胶粘剂配方粘合木材的剪切强度均大于1.96MPa,成本比较低廉;(2)所选定的增塑剂DBP用量对粘合强度影响特别显著,应当重视乳白胶胶粘剂中增塑剂总含量的选择;(3)根据正交表的方差分析确定胶粘剂的最优配方是A_2B_1C_1D_1。     

木材胶粘剂的研究现状和发展趋势

本文综述了木材胶粘剂的国内外现状；论述了各种木材胶的结构及作用机理，结合各胶种的优缺点介绍了其应用情况，重点讨论了水性聚氨酯胶粘剂作为木材胶的特点及优势：指出了我国木材加工领域用胶存在的问题和发展趋势。     

低甲醛释放木材胶粘剂研究进展

我国已成为世界人造板生产大国,木材胶粘剂年用量已超过400万t,其主要胶种为甲醛类合成树脂胶粘剂.本文评述了木材胶接用甲醛类合成树脂胶粘剂的开发研究、生产应用及发展,重点综述了低甲醛释放的脲醛树脂、三聚氰胺-尿素共缩合树脂和酚醛树脂胶粘剂的研究进展和开发应用情况,并对其发展趋势等进行了展望.     

本期特约专栏主持人——顾继友

<正>主持人语:木质胶接材料与制品已经成为木质材料与制品的主体,故此胶粘剂和胶接技术在木材加工业占有非常重要地位,木质胶接材料质量的提高和新产品的开发都离不开胶粘剂和胶接技术的进步。着眼于木质材料和制品的发展趋势,在把握木材胶粘剂的低成本化和环保化特点的前提下,从我国木材胶粘剂使用现状、急需解决的关键技术问题和未来发展的角度,介绍木材加工业胶粘剂的应用、存在的问题和未来发展趋势,主要阐述醛类胶粘剂、     

只有创新 才能前进 木材胶粘剂五十年的发展与今后预测

新中国建国 50年来 ,木材用胶粘剂迅速发展。预计 2 1世纪前期 ,将更从胶的合成理论、胶的品种、胶合工艺中有创新。胶粘剂也将适应社会生态环境 ,持续的发展。     

乙烯基乳液-异氰酸酯木材胶粘剂的研究

介绍了一种乙烯基乳液－异氰酸酯木材胶粘剂，探讨了配方中主要成分对胶粘剂性能的影响。该胶具有良好的胶接性、耐水性。     

我国木材工业用胶粘剂的现状、存在问题及对策

本文介绍了脲醛树脂胶粘剂、酚醛树脂胶粘剂、三聚氰胺甲醛树脂胶粘剂、聚醋酸乙烯乳液胶粘剂、聚氨酯胶粘剂、热熔胶粘剂等木材工业用胶粘剂的现状和研究进展。分析了目前木材工业用胶粘剂存在的问题,初步提出了解决问题的对策。     

耐水性木材用脲醛粘合剂的研究

研究了改进胶合板用脲醛粘合剂的耐水性的方法。针对脲醛粘合剂耐水性低的原因,提出在胶液中添加碱性物质——耐水添加剂,可显著改善胶合板的耐水性,几种添加剂并用,胶合板可达一级耐水板的水平。     

Development and characterization of a wood adhesive using bagasse lignin

Bagasse is spent fiber left after extraction of sugar. It is mainly used as a fuel to concentrate sugarcane juice. In the present work, the possibility of preparing wood adhesives from bagasse has been explored. The parameters for the preparation of a lignin phenol formaldehyde (LPF) adhesive, (lignin concentration, formaldehyde to phenol molar ratio, catalyst concentration, reaction time and reaction temperature) have been optimized. It was found that up to 50% of phenol can be substituted by bagasse lignin to give LPF wood adhesive having better bonding strength in comparison to a control phenol formaldehyde (CPF) wood adhesive. Prepared resins were characterized using IR, DSC and TGA. IR spectra of LPF resin showed structural similarity with CPF resin. Thermal stability of LPF resin was found to be lower as compared to CPF resin. DSC studies reveal a lower curing temperature for LPF adhesive in comparison to CPF adhesive. A shelf-life study reveals that LPF exhibits consistent behavior as compared to CPF in respect to adhesive strength.     

木质素胶粘剂的开发和应用

木质素作为植物中蕴藏量仅次于纤维素的高聚物,是一种廉价易得,储量丰富,环境友好的可再生天然资源。文章主要就木质素的结构和性能以及在各类用途胶粘剂中的应用作了详细的概述。     

木材用脲醛树脂胶粘剂研究进展

介绍了脲醛树脂的形成机理,综述了木材用脲醛树脂胶粘剂的研究进展和工艺的影响因素,提出环境友好型脲醛树脂胶粘剂是未来发展趋势。     

水相中合成木质素环氧树脂及其在木材胶黏剂中的应用

以木质素为原料,在水相中合成一种适用于木材胶黏剂的木质素环氧树脂。为了考察木质素环氧化反应条件对木质素环氧树脂的羟基和环氧基的影响,以及对胶合板的胶合强度的影响,采用FT-IR和31PNMR对木质素环氧树脂结构进行表征,并用TG和DTG对木质素环氧树脂的热稳定性进行分析。结果表明,环氧化反应主要发生在酚羟基上,在反应过程中,相比环氧氯丙烷,NaOH的加入量对木质素环氧树脂结构和胶合板的胶合强度影响更大。随NaOH加入量增加,木质素环氧树脂中环氧基团逐渐增多,胶合板的胶合强度呈现先升高、后降低的趋势。当木质素的羟基与NaOH摩尔比为1:1时,由木质素环氧树脂制得的胶合板胶合强度达到最大,湿强度达1.61 MPa,超过国家标准II类板的要求(≥0.7 MPa)。采用扫描电镜研究了黏接机理,发现环氧化程度提高时,固化后的木质素环氧树脂的结构更加稳定且致密,导致胶合板的胶合强度也提高。但过高的环氧化程度会增大胶黏剂的粒径,导致胶黏剂与木板不能形成更好的机械互锁结构,从而降低胶合板的胶合强度。还进一步简化了木质素环氧树脂木材胶黏剂的合成工艺,使环氧化反应后的体系无需处理即可直接应用于木材胶黏剂,减少了胶合板生产工艺流程。此外,经过30天的储存期,胶黏剂黏合强度没有明显下降。通过与商业脲醛树脂木材胶黏剂对比,其黏接强度可以达到商业脲醛树脂的水平。     

Synthesis of wood‐based epoxy resins and their mechanical and adhesive properties

Wood‐based epoxy resins were synthesized from resorcinol‐liquefied wood. Wood was first liquefied in the presence of resorcinol with or without a sulfuric acid catalyst at high temperature. Because of the hydroxyl groups, the resorcinol‐liquefied wood was considered as a precursor for synthesizing wood‐based epoxy resin. Namely, the phenolic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition. By the glycidyl etherification, epoxy functionality was introduced to the liquefied wood. The epoxy functionality of the resins was controlled by the concentration of phenolic OH groups in the liquefied wood, which would be a dominant factor for crosslink density and properties of the cured epoxy resins. The flexural strength (150–180 MPa) and the modulus of elasticity (3.2 GPa) of the highly crosslinked wood‐based epoxy resin were equivalent to those of the commercially available epoxy resin, diglycidyl ether of bisphenol A (DGEBA). Also, the shear adhesive strength of the wood‐based epoxy resin was higher than that of DGEBA when plywood was used as the adhesive substrates. The mechanical and adhesive properties suggested that the wood‐based epoxy resins would be well suited for matrix resins of natural plant‐fiber reinforced composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2285–2292, 2006     

A Soy Flour-Based Adhesive Reinforced by Low Addition of MUF Resin

The desire to prepare a lower-cost soy-based adhesive has led to an interest in using the abundant and inexpensive soy flour (SF) as a substitute for expensive soy protein isolates (SPI) in wood adhesives. However, the weakness of this adhesive is poor water-resistance and bonding strength due to a low protein content, which limits its application in the wood industry. The objective of this research was to provide a simple and useful approach for improving the adhesion performance of SF-based adhesive by introducing a small addition of melamine-urea-formaldehyde (MUF) resin into the cured system. The optimum addition level of MUF resin, as well as the adhesion performance and conformation change of SF-based adhesive, were investigated. The analytical results indicated that the co-condensed methylene bridges were formed through the reaction of methylol groups of MUF resin with soy units during the hot-press process. The addition of MUF resin, not only significantly decrease the viscosity of SF-based adhesive but also increase its water-resistance and wet shear strength value. The SF-based adhesive containing 20% MUF resin, is a relatively low-cost adhesive, has a reasonable viscosity, and moreover can pass the Chinese Industrial Standard requirement (0.7 MPa) for interior plywood panels.     

Wood–phenol adhesives prepared from carboxymethylated wood. I

Preparation of carboxymethylated wood (CM wood)–phenol resin adhesives has been attempted by two methods, “kneading method” and “solvolysis method,” and their adhesion strength has been studied. The two preparation methods differ in the dissolution step. In the case of the kneading method, CM wood was dissolved in aqueous phenol by kneading at 100–120°C under shear, whereas, in the case of the solvolysis method, the dissolution was facilitated by phenolysis at 80°C in the presence of appropriate amounts of hydrochloric acid. The wood-based adhesive prepared by the solvolysis method revealed excellent and enhanced applicability compared with that of the adhesive prepared by the kneading method, although the latter can be used as an adhesive for wood. Adhesion strength of these adhesives was enhanced when poorly substituted CM wood and appropriate amounts of formaldehyde were used in the resin preparation. A crosslinking agent for carboxymethyl cellulose, that is, polymeric MDI, was also added just before application. The water-proof adhesion strength was higher than the JIS specification for phenol resin adhesives for this modification.     

木焦油部分替代苯酚合成酚醛树脂胶粘剂的研究

采用简单蒸馏法，获得木焦油中150-250℃的馏分；采用气质联用仪（GC—MS）对此馏分的成分进行了分析，确定了37种化合物，其中酚类化合物的相对含量为40％，占总体木焦油的11％以上、用木焦油部分替代苯酚合成酚醛树脂胶粘剂，同时采用一次投甲醛法，对焦油替代量、反应温度、反应时间、催化剂含量等工艺参数进行了正交化试验，确定了最佳工艺条件？制得的酚醛胶的性能符合GB／T14074—2006的要求，胶合强度高达308MPa。采用木焦油的部分替代苯酚，降低了酚醛树脂胶粘剂的成本，也为木焦油的利用提供了一条途径，因此具有良好的工业前景与环境效益