活性染料对杨木单板染色后胶合性能的影响

为了研究活性染料对染色单板胶合性能的影响,分别采用环保型低毒脲醛树脂胶和单组分湿固化异氰酸酯胶进行杨木染色单板的胶合,测试染色后杨木单板的润湿性和胶合强度,结果得出:染色处理能够在一定程度上增加单板的孔隙度,有利于黏度较低的胶黏剂的铺展,也有利于改善其胶合性能;对于黏度较大的胶黏剂则影响不明显。     

单板含水率对湿固化异氰酸酯胶性能的影响

研究了木材含水率对湿固化异氰酸酯胶黏剂(YQJ-S)性能的影响。结果表明,木材含水率越高,YQJ-S润湿性和渗透性越好,且固化反应起始温度越低。因YQJ-S固化反应活化能较低,可在室温下与高含水率木材发生固化反应。当木材含水率为70%时,YQJ-S胶接强度最大。     

湿固化胶粘接高含水率桦木的润湿性能与胶接性能的关系

欲达到良好的界面胶合或高强度的胶接接头,胶黏剂在木材表面上的润湿性是非常重要的,而含水率对木材润湿性具有极为重要的影响。以胶黏剂在桦木表面的润湿眭能为着眼点考虑胶接问题,采用单组分湿固化异氰酸酯胶黏剂粘接高含水率桦木,引入润湿模型,用平衡接触角θ和扩散-渗透系数K分别从胶滴的最终铺展状态和胶滴的扩散、渗透能力两个不同方面对润湿性能进行了描述,探讨了在高含水率条件下,桦木的润湿性能与胶接性能的内在联系。结果表明:桦木含水率从50%增大到90%时,含水率越高,桦木初始接触角越小,平衡接触角越大,扩散-渗透系数K值越小,胶液在桦木表面的润湿性能越不好,其胶接强度越低。     

异氰酸酯树脂胶粘剂

自60年代起,发达国家就开始研究降低游离甲醛和游离酚的问题。异氰酸酯树脂胶粘剂属非甲醛系合成树脂胶粘剂,不存在甲醛污染问题,并且胶接性能优良、施胶量低、热压周期短、使用的刨花含水率范围广(0～35%)、胶接耐水性和胶接耐久性远优于脲醛树脂胶粘剂。异氰酸酯树脂胶粘剂在人造板生产上的应用将会不断增加。特别是在利用农作物秸秆代替木材生产人造板方面将发挥极其重要的作用。     

单组分快速湿固化聚氨酯木材胶黏剂的研制

针对30min内胶接桦木生材(含水率在60%～90%)集成木方的生产需要,采用聚醚多元醇、多亚甲基多苯基多异氰酸酯(P-MDI)为主要原料制备单组分快速湿固化聚氨酯木材胶黏剂,以表(?)时间,常温凝胶时间和干、湿状压缩剪切强度为指标,通过正交试验确定合成工艺的主要参数:—NCO:—OH摩尔比值(R)大小、聚乙二醇(PEC)分子量大小和溶剂量与增塑剂量的比例,探讨了各项因素对胶黏剂性能的影响,并根据实际生产需要,优化出最佳方案。结果表明:所合成胶黏剂压制桦木生材集成木方的主要性能指标,均超过日本JISK6806—2003Ⅰ类板的标准要求。     

软木贴面定向结构麦秸板的胶合工艺

为提升定向结构麦秸板的装饰性能,采用冷压法对其进行软木贴面处理,分析压力、加压时间、涂胶量、胶种对贴面板胶合性能的影响.结果表明:采用异氰酸酯胶,在压力1.0MPa、加压时间30min、涂胶量80g/m2(单面)的条件下,软木贴面定向结构麦秸板的表面胶合强度、浸渍剥离长度,满足GB/T 15104-2006《装饰单板贴...     

降低胶合板耗胶量的措施及其效果综述

目前,胶粘剂成本的高低是影响人造板企业经济效益的主要因素之一。胶粘剂中添加填充剂、选择新的施胶法、采用高含水率胶合技术、对单板进行预处理、降低树脂的固定含量、提高单板质量、采用无胶胶合技术,都是减少胶合板耗胶量的具体措施。     

施胶工艺对常压冷等离子体处理改善杨木单板胶合特性的影响

采用常压介质阻挡放电产生的冷等离子体对杨木单板进行改性处理,研究单板含水率、涂胶量和胶黏剂种类对杨木单板胶合特性的影响,结果表明:常压冷等离子体处理能显著地改善不同制板工艺条件下杨木胶合板的胶合强度,提高率可达15％～45％.含水率越低,等离子体处理后强化胶合强度的效果越好,并且对于UF、MUF、PF三种胶黏剂,常压冷等离子体处理均可在常规胶量下增强杨木单板的胶合强度,表明了常压等离子体处理可运用于工业化生产,并且是降低成本和甲醛释放量的一个有效方法.     

人造板用异氰酸酯胶粘剂的性质与应用

介绍了用荧光显微技术和ＤＳＣ分析方法研究人造板用异氰酸酯胶粘剂的胶接特性，以及近年来异氰酸酯在人造板中的应用。国内外研究结果表明，以异氰酸酯作为人造板胶粘剂可获得较ＰＦ、ＵＦ胶粘剂更牢固的化学胶接，尤其用于农作物秸杆（麦草、稻草）的胶接可得到符合我国木质Ａ类优等品标准的刨花板。     

盛基颐家YJ-132无甲醛胶合板热压胶使用操作规程及质量控制点

1.单板质量控制 1.1单板进厂时应及时测定单板含水率,单板含水率应控制在8％～12％范围内,以保证良好的胶合.如果单板含水率大于12％时应及时处理以防鼓泡,单板含水率过低则就适当加大涂胶量,生产中所使用的单板应在加工前进行测量.     

秸秆板贴面用异氰酸酯胶的改性

通过对异氰酸酯(API)主剂进行改性,从而减少交联剂的用量,降低API胶黏剂的生产成本。将改性API胶黏剂用于秸秆板薄木贴面的试验表明,当主剂、交联剂、填料之比为100∶4∶30,热压温度为60~110℃时,秸秆板的贴面效果达到相关国标要求。     

导热油加热的连续热压干燥机干燥速生杨单板的应用研究

导热油作载热体,在速生杨木单板连续式热压干燥中应用后,效果良好。美洲黑杨生材单板(名义厚度1．7mm)可在2min内于至8％以下的含水率。干单板基本平整、光滑,终含水率均匀,无撕裂。单板厚度干缩率平均5．3％,横纹干缩率4.9％。胶合强度平均0．812MPa,略高于网带对流干燥单板胶合强度0．779MPa。研究结果表明,此法干燥速生杨木单板是可行的。     

三种松木单板的胶合工艺条件和胶合性能的改善

用ＵＦ、ＭＵＦ胶制作三种松木胶合板，分别就单板厚度、涂胶量及抽提物含量对胶合性能的影响，松木与柳安混合树种组坯、特殊添加剂对改善胶合性能的作用进行了研究。结果表明：除了老挝松边材ＭＵＦ胶合板以外，１．５和２．０ｍｍ厚的单板胶合强度均达到或超过日本ＪＡＳ普通胶合板的要求。合板胶合强度随单板厚度增加而下降，在一定范围内增加涂胶量可以提高合板胶合强度，混合组坯及施加特殊添加剂具有改善松木单板胶合性能的作用。     

玉米淀粉改性UF树脂胶合高含水率单板

采用半酯化的玉米淀粉与脲醛树脂(UF)共聚改性,探讨加入量、脲醛树脂的量比、混合比、热压条件等对胶液的黏度、稳定性、固化时间及胶合质量的影响.结果表明:当单板含水率提高到16%～18%时,用改性UF树脂生产的多层胶合板,其物理力学性能指标达到GB/T 9846.1～12-88中Ⅱ类胶合板的要求,并大幅度地降低了胶合板的制造成本.     

Shear strength development of the phenol–formaldehyde adhesive bond during cure

The development of the shear strength of the phenol–formaldehyde (PF) adhesive bond during curing was investigated. Five different PF adhesive mixtures and 1.1 mm thick peeled beech (Fagus sylvatica L.) veneer were used to produce lap-shear specimens, which were cured at a pressing temperature of 160°C. Dielectric analysis (DEA) and modified ABES (automated bonding evaluation system) were used to evaluate the physical–chemical and mechanical aspects of PF adhesive cure in a miniature hot-press. The degree of cure, which was calculated from conductivity data, was dependent on pressing time and the composition of the PF adhesive. An addition of rye flour to the PF adhesive significantly postponed the curing process as determined by DEA. It was found that the adhesive bond started to develop in the last stage of the curing (vitrification), by which time most of the physical–chemical conversion of the adhesive had been completed.     

水性异氰酸酯交联剂的应用研究

采用不同链长的聚醚多元醇与多亚甲基多苯基多异氰酸酯（PAPI）反应,制备了两种不同结构的水性异氰酸酯（P-C、P-D）,联剂分别加入到氧化玉米淀粉胶黏剂和脲醛树脂胶黏剂中,以改善胶黏剂的胶接性能。通过粘接强度测试研究不同结构、不同用量的水性异氰酸酯对改性胶黏剂的胶接强度和耐水性的影响。实验结果表明：氧化玉米淀粉和脲醛树脂中加入水性异氰酸酯交联剂制备胶合板,胶接强度及耐水性均有显著提高。氧化玉米淀粉胶黏剂中加入10%的水性异氰酸酯P-D后,所制备胶合板的干态剪切强度可达2.64MPa。脲醛树脂胶黏剂中加入7.5%的P-D后,干态、湿态剪切强度分别为1.24MPa和1.23MPa,甲醛释放量为0.31mg/L,达到E0级标准。     

异氰酸酯树脂胶粘剂刨花板制板工艺研究

研究了用异氰酸酯树脂胶粘剂制造刨花板的工艺条件,详细讨论了热压温度、热压时间、密度含水率、施胶量和施蜡量和对刨花板为物理力学性能的影响。结果表明：刨花含水率是继热压工艺三个因素之后的重要影响因子。研究中还发现了“厚度膨胀率平行性”现象,对其进行的深入分析研究揭示了不可逆厚度膨胀率为２４ｈ吸水厚度膨胀率的关系,总结出板材２４ｈ吸水厚度膨胀率的改善只能通过改善不可逆度膨胀率获得。研究结果还表明,利用Ｙ     

Study on drying rate in contact drying with flexible screen

IntroductionA new type contact dryer with non-metal flexibleplaten was patented in 1998 in China, which specialstructure and material solved the problem of low productivity in platen drying. The machine was similar tohot press. Direct contact betWeen wood and heatedplaten allows rapid heat transfer by conduction (Sandoe 1983). Though the flexible screen conducts heatslower than metal platen does, it transfers massmuch fast6r. So water removing rate decides veneerdrying rate in the new machin…     

水性异氰酸酯胶合板与细木工板的研究

以水性异氰酸酯胶粘剂试制胶合板和细木工板。研究结果表明,单板的材种和施胶量等对异氰酸酯胶合的板材性能有较大影响;采用异氰酸酯,胶合板用胶量较少,在施胶量为200g/m~2时,马尾松、杨木、荷木、枫木单板制成的胶合板胶合强度均能达到GB/T5849-1999的要求,枫木作中板的细木工板在施胶量为250g/m~2时胶合强度和横向静曲强度均达到国家标准;根据试验结果并结合生产实际的成本分析表明,胶合板成本增加了81～189元/m~3,细木工板的成本增加了120元/m~3和104元/m~3。     

A new quantitative method for evaluation of adhesive penetration pattern in particulate wood-based composites: elemental counting method

The importance of adhesion in production of wood-based composites is well-known. Adhesive penetration and interphase morphology play an important role in bond strength and product performance. Many studies offered different methods for interphase characterization and analysis. Both qualitative and quantitative methods have been used to analyze the bondline. Most of the quantitative methods were developed for bonded assemblies of veneer or wood blocks. Adhesive penetration measurement in particulate wood-based composites is the main scope of this study. For this purpose, uniform oriented strand board with veneer strands was produced by the use of phenol formaldehyde resin with 2, 6, and 10 % strand moisture content (MC). The strands were formed into well-organized mats to achieve a uniform structure for the composite. Cross-section specimens were prepared from each board and observed by epifluorescence microscopy. Six positions for growth-ring angle in adhesive joints were denoted to evaluate penetration in different directions of the wood. Four parameters were also determined to quantify resin penetration patterns by counting the quantity of the main anatomical elements of wood, which were filled with resin. Finally, it was determined that this method could recognize the differences between adhesive penetration in boards produced with different level of strand MC. Resin penetration in strands with 6 and 10 % MC was the greatest. Growth-ring angle of the strands influenced penetration as it was increased when both strands meet each other in an oblique position, although this effect was significant only in maximum penetration depth in fibers.