我国木材工业用胶黏剂与胶接技术现状和展望

介绍木材工业使用胶黏剂的种类、性能及其特性,以及我国木工胶黏剂生产应用的现状、存在的问题和发展趋势.从被胶接材料、调配胶技术、胶接的表界面和胶接性能角度出发,提出了木材胶接技术对合理使用胶黏剂和提高胶接效能的重要作用问题.     

生物质木材胶黏剂的研究进展

综述了几种重要生物质木材胶黏剂即单宁、木素、大豆蛋白、淀粉及木材原料基木材胶黏剂的研究进展情况,分析了生物质木材胶黏剂的应用现状,探讨了生物质木材胶黏剂的研究方向及发展趋势.     

植物酚类PF树脂胶的研究现状及发展趋势

利用植物酚类化合物代替苯酚制备酚醛树脂胶黏剂,可扩大酚类原料来源,降低生产成本,并促进资源的可持续利用.通过对木素胶黏剂、单宁胶黏剂、木材液化产物胶黏剂和木材热解油胶黏剂的研究进展和现状进行系统归纳,指出目前植物酚类化合物胶黏剂存在的问题,并对其发展做出了预测.     

我国木材胶黏剂的开发与研究进展

木质原料结构的变化促使木质材料由实体木材向胶接木质材料方向发展,胶接木质材料的发展极大地依托于木材胶黏剂发展和技术进步。笔者从胶接木质材料的发展角度简述了我国木材胶黏剂的开发研究和生产应用状况,以及目前存在的技术问题和今后木材胶黏剂的发展趋势。     

国内乳液胶黏剂在木材工业中的应用现状与趋势

乳液胶黏剂具有无甲醛释放、常温快速固化的特性,能够适应当前国内木材工业用胶黏剂的要求。本文介绍木材加工用乳液胶黏剂的种类、改性方法及生产研究现状,在此基础上提出木材加工用乳液胶粘剂的发展趋势。     

木质素基非甲醛木材胶黏剂的研究进展

木材行业当前使用的胶黏剂原料主要来自石油资源,石油资源的不可再生性和人们对环境问题以及胶黏剂中有毒挥发性物质的日益关注,迫使人们寻找一种可再生的,能够制备非甲醛木材胶黏剂的替代物。木质素是一种价格低廉、产量巨大的可再生生物质资源,其在木材胶黏剂领域的应用得到了人们的关注。从木质素-糠醛胶黏剂、木质素-聚氨酯胶黏剂、木质素-单宁胶黏剂、木质素-聚乙烯亚胺胶黏剂、漆酶活化木质素胶黏剂和木质素-大豆蛋白胶黏剂等方面综述了木质素基非甲醛木材胶黏剂的研究进展,并对其存在的问题及解决对策进行了分析,对木质素基非甲醛木材胶黏剂的前景进行了展望。     

生物质基无甲醛胶黏剂的研究进展

木材加工行业当前使用的胶黏剂原料主要来自石油资源,石油资源的不可再生性和人们对环境问题以及胶黏剂中甲醛等有毒挥发性物质的日益关注,迫使人们寻找可再生的无甲醛木材胶黏剂。利用价格低廉的可再生资源开发无甲醛环保型胶黏剂是我国木材胶黏剂行业的研发方向。因此,研究生物质基无甲醛木材胶黏剂具有重要的科学意义和应用前景。生物质胶黏剂普遍存在黏度大、胶合强度低、耐水性差等问题,围绕如何解决这些问题,研究人员进行了大量的研究。主要介绍了大豆蛋白基无甲醛胶黏剂、淀粉基无甲醛胶黏剂、木质素基无甲醛胶黏剂的国内外研究现状,并对其存在的问题及解决对策进行了分析,同时,对无甲醛胶黏剂的前景进行了展望,以期为生物质基无甲醛胶黏剂在木材加工领域的应用提供参考。     

生物质胶黏剂的研究进展

综述了胶黏剂工业的生产应用现状;详述了近年来改性生物质胶黏剂的研究进展及在木材行业中的应用,特别是对蛋白和淀粉胶黏剂作了详细介绍;指出了生物质胶黏剂当前存在的问题并对其发展方向与前景进行了展望。     

木材工业用胶黏剂生产现状、存在的问题与对策

近年来随着木材工业,特别是人造板工业的迅猛发展,我国木材工业用胶黏剂产量大增,按人造板产量推算,主要胶种UF、PF、MF的2004年消耗量300万t以上。但是胶黏剂行业存在着生产单位过于分散,规模小等问题,因而产品质量有较大差异,产品研发能力不足。笔者建议发展规模经营和专业化生产以促进木工胶黏剂行业的健康发展。     

我国淀粉基木材胶黏剂的研究与应用

回顾近年来淀粉及其衍生物在木材胶黏剂中的应用,重点介绍氧化淀粉、酯化淀粉、接枝共聚淀粉应用于木材胶黏剂的原理及工艺,及其对胶黏剂性能的影响,分析不同工艺的优缺点及应用前景,探讨淀粉及其衍生物木材胶黏剂的发展趋势。     

Shear strain distribution in PRF and PUR bonded 3–ply wood sheets by means of electronic laser speckle interferometry

The distribution of shear strain across a 3–ply wood sheet bonded with PRF and PUR, respectively, was measured by means of electronic laser speckle interferometry. Owing to the higher shear modulus of PRF compared to PUR, shear strains were more evenly distributed in PRF bonded specimens than in PUR bonded specimens. However, considering the different shear moduli of earlywood and latewood bands in the core layer of the 3–ply sheet, it is concluded that shear stress is distributed more evenly along PUR bond lines compared to PRF bond lines. Since it is less prone to stress concentrations, PUR should provide more durable adhesive connections than stiff adhesives such as PRF.     

A feasibility study of using two-component polyurethane adhesive in constructing wooden structures

This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.     

ACQ防腐处理对马尾松木材胶合强度的影响研究

采用铜氨(胺)季铵盐(ACQ-D)防腐剂处理马尾松木材,以水性高分子异氰酸酯(API)、聚氨酯(PUR)和间苯二酚-苯酚-甲醛树脂(RPF)为胶黏剂制备防腐材胶合试样,研究胶黏剂种类和防腐剂处理浓度对马尾松胶合强度的影响。结果表明:API、PUR、RPF适用于ACQ处理马尾松的胶合,平均剪切强度和木破率均达到GB/T 26899—2011《结构用集成材》要求。胶黏剂种类对防腐材胶合强度有显著影响,表现为PUR和RPF的剪切强度优于API。与未处理材相比,ACQ处理对API胶合有负面影响,对PUR胶合有增强效应,对RPF胶合没有显著影响。在ACQ浓度为0.1%～1.0%范围内,胶合强度没有显著变化。     

高温热处理木材胶合性能的研究

笔者研究了桦木、落叶松和樟子松高温热处理材的胶合性能,并与常规干燥材进行了对比。测试结果表明木材的胶合剪切强度与所用的胶黏剂有关,聚氨酯胶合的三个树种木材的剪切强度普遍大于白乳胶胶合的木材。无论是室内用的白乳胶或室外木结构用的聚氨酯胶都能与三个树种的高温热处理材很好地胶合,胶合试件的浸渍剥离率或煮沸剥离率皆为零。木材经高温热处理后,其剪切强度均有不同程度的降低,阔叶材桦木下降幅度最大,针叶材落叶松下降幅度最小。     

Influence of growth ring angle,adhesive system and viscosity on the shear strength of adhesive bonds

Abstract

To investigate the influence of growth ring angle, adhesive system and viscosity on the bonding properties of adhesive bonds, shear tension tests according to DIN EN 302-1 (2004) were conducted using one-component moisture-curing polyurethane, polyvinylacetate and urea-formaldehyde. Significant differences between the systems could be detected, which were reflected in the predominant failure behaviour for each system. Specimens showing wood failure were influenced mainly by the wood factors, whereas samples which had failed in the adhesive part of the bond differed only in the adhesive properties. The growth ring angle showed the same tendencies as it does in plain wood. Therefore, to gain more information on the adhesive performance in the bond, a loading along the LT plane seems more appropriate for beech wood used in DIN EN 302-1 (2004).     

两种常温固化木材胶粘剂胶接强度分析

对两种木材用常温固化胶粘剂--单宁-甲醛胶粘剂和聚氨酯胶粘剂胶接的速生杨木的静态剪切强度进行了测试与分析.研究结果表明,以速生杨I-72为被胶接对象,自制的双组分型单宁胶压缩剪切强度范围为8.08～8.92MPa,但木破率较低,要满足日本集成材JAS标准中用胶规定,需进一步研究改进.相比较而言,聚氨酯胶粘剂的胶接强度较高,其压缩剪切强度值均在9.8MPa以上,木破率在75%以上,能够满足日本集成材JAS标准中用胶的规定.     

Tensile strength of softwood butt end joints. Part 2: Improvement of bond strength by a hydroxymethylated resorcinol primer

Abstract

In a previous study it was shown that the mechanical stability of an end-grain joint bonded with a one-component polyurethane adhesive (PUR) was insufficient compared with melamine–urea–formaldehyde and phenol–resorcinol–formaldehyde bonding. Based on this, the aim of this study was to improve the mechanical stability of the end-grain joint by means of a hydroxymethylated resorcinol (HMR) primer and by increasing the spreading quantity. To study the effect of HMR and the increased spreading quantity on the adhesive bond strength of end-grain to end-grain-bonded wood samples, three-part Norway spruce wood specimens were tested in tension. Before bonding, each end-grain surface was treated with an aqueous solution of HMR. The two axially orientated outer parts of the specimens were jointed with the middle part using a PUR adhesive. Compared with untreated, i.e. non-primed samples, the tensile strength of HMR-treated specimens was more than doubled. Furthermore, a positive effect of increased adhesive spread was shown for untreated PUR-bonded samples. An increase in adhesive spread by a factor of 1.6 led to an improvement in tensile strength by a factor of about 2.6.     

Improving the thermal stability of one-component polyurethane adhesives by adding filler material

The aim of the current study is to improve the thermal stability of one-component moisture-curing polyurethane adhesives. The approach here tends to add suitable filler materials to the adhesive and to study the resulting effects. The investigation covers mechanical tests to determine the shear strength of the glued wood joints according to EN 302-1 (2004). Furthermore, the distribution of the filler material within the adhesive is shown by means of environmental scanning electron microscopy combined with energy-dispersive X-ray spectroscopy analysis. The thermal stability of the glued wood joints could be significantly improved by adding chalk with a volume fraction of 30% to the adhesive.     

国外刨花板质量控制与我国的发展前景

刨花板质量控制的目的就是保证产品质量,降低生产成本,以提高经济效益。文章通过剖析国外刨花板质量控制技术的发展和3种不同水平的刨花板质量控制方法,指出了我国目前刨花板生产存在质量问题的主要原因,提出了扭转我国产品质量现状的3项质量控制技术。     

统计过程控制技术在产品质量控制点中的应用

在产品质量控制点中应用统计过程控制技术,通过控制图分析过程的稳定性,对过程存在的异常因素进行预警,计算过程能力指数,分析稳定过程能力满足技术要求的程度,并对过程质量进行评价,以使生产过程处于统计控制状态。