摘要
单板层积材(Laminated Veneer Lumber,简称LVL)具有轻质高强、力学性能稳定、尺寸规格灵活等特点,是一种高性能、生态环保的新型建筑复合材料。近年来,国内单板层积材发展迅猛。利用改性处理的速生人工林木单板,制造强度高、纹理美观的强化单板层积材,不仅能有效利用我国林木资源,而且大大提高了速生木材的产品附加值。
本论文是在前人对杨木及单板层积材研究的基础上进行总结,结合实际情况对速生杨木单板增强来制造杨木单板层积材,并对其物理性质和力学强度进行了一系列的研究。研究是以速生杨木为主要原材料,用水溶性低分子量脲醛树脂、水溶性低分子量酚醛树脂浸渍处理,来制备强化杨木单板层积材。在制备强化杨木单板层积材的过程中,探讨了最佳的浸渍工艺,并通过讨论抽真空时间、树脂固体含量、浸渍温度、常压浸渍时间4个变量因子,建立材料的性能与工艺因子的关系,找出制备的最佳工艺参数。根据生产设备条件和产品的最终用途、最终性能要求,建议脲醛树脂浸渍生产工艺参数为：抽真空时间为30min、树脂固体含量为30%、浸渍温度为30-35℃、常压浸渍时间为3h；酚醛树脂浸渍生产工艺参数为：抽真空时间为30min、浸渍固体含量为25%、浸渍温度为35-40℃、常压浸渍时间为9h。
通过试验方法的改进,结果表明试件的物理力学等性能,完全可以达到结构单板层积材E1标准,酚醛树脂增强杨木单板层积材达到室内外装饰结构木的要求、脲醛树脂增强杨木单板层积材达到了室内非结构用装饰木的要求。
此外,通过红外光谱分析,发现浸渍增强杨木单板层积材的红外光谱与树脂的红外光谱相差并不大,对比树脂的合成工艺,可以知道树脂只是机械的填充在杨木中。透过电镜观察,发现酚醛树脂浸渍的杨木单板层积材的浸渍效果比脲醛树脂的好,树脂浸入杨木单板中时,主要是从细胞间隙浸入木材内部,其次才是透过细胞壁进入木材；通过观察发现导管的横向渗透性能比管胞细胞差很多。
LVL (Laminated Veneer Lumber, referred to as LVL) which has high strength, stable mechanical properties, flexible sizes features, is a new-construction composite materials of high performance and eco-environmental characteristics. In recent years, Chinese LVL was developing rapidly. Using fast-growing artificial wood veneer which had been modified manufacture high strength and beautiful texture enhanced laminated veneer lumber, which not only can be used efficiently our forest resources, but also the fast-growing wood products'added value improved greatly.
This paper is based on the summary of predecessor's research on Poplar and LVL, to create an enhanced poplar LVL in accordance with the actual situation on the poplar wood veneer, and to conduct a series of studies on its physical properties and mechanical strength. This research use Poplar veneer as the main raw materials, use low molecular weight water-soluble PF and UF resin as dipping liquid, to manufacture intensified Poplar LVL. In the process of manufacturing intensified Poplar LVL, explore the best impregnation process, to establish the relationship between material properties and Process Factors by discussing the soaking time in the vacuum, the resin solid content, soaking temperature, soaking time at room temperature, and then identify the optimal process parameters. According to the conditions of production equipment and the product end-uses of the final performance requirements, recommending the best urea-formaldehyde resin impregnated technology parameters are:the soaking time in the vacuum is 30min,25%solid resin content, soaking temperature of 30-35℃, atmospheric pressure impregnation time is 3h; The best process parameters of PF resin impregnated production were:the soaking time in the vacuum is 30min,25%solid resin content, dipping temperature is 35-40℃, atmospheric pressure soaking time is 9h.
Through the improvement of test methods, the results show that the physical mechanics properties of the specimen can completely meet the Japanese JAS standards FC1 laminated veneer lumber, Poplar LVL enhanced by PF resin can used indoor and outdoor decorative wooden structure requirements, UF Resin enhanced Poplar LVL reached interior non-structural decorative wood requirements.
In addition, through infrared spectroscopy can find that there is not significant difference between the infrared spectra of soaking enhanced poplar LVL and the IR spectra of resins, and can know that the resin only filled mechanically in the poplar veneer compared to the resin's synthesis process; Through the electron microscope can found that the result of PF resin impregnated Poplar LVL is better than urea-formaldehyde resin impregnated. When resin immersed in poplar veneer, the main gap is immersed in wood from the cells inside, then followed by cell wall into the timber; at the same time, observed that the lateral permeability of the ducal cells is much worse than the tracheid cells.
引文
[1]孟宪树,陆从进.新型结构材料-单板层积材.中国林业科学院木材工业研究所.
[2]鲍甫成,傅峰.人工林杨木材性对单板层积材强度的贡献率[J].林业科学,1999.35(2)：87-94.
[3]陆从进.论小径速生树材生产单板层积材技术的推广[J].木材工业,1991.5(1)：36-37.
[4]朱照纲,郭飚.单板层积材及其应用[J].林业科技,2001,26(3).
[5]吴盛富、唐召群、吕斌.胶合板厂技术改造和单板层积材生产[J].木材工业,1998,12(6)：24-27.
[6]黄松军.增强杉木单板层积材工艺研究[D].北京.北京林业科技大学,2008.06.
[7]苏福妹.一种新型结构材料—单板层积材[J].江西林业科技,1990,(1).
[8]吕斌,付跃进、吴盛福、唐召群.几种人工林树种单板层积材的生产试验及力学性能的研究[J].林产工业,2004,31(3)：13-17.
[9]Exploiting a marketing niche.Wood Based Panels Internationai,1991,2.
[10]R C Tang, J P pu. Edgewise bending properties of laminated veneer lumber: Effect of veneer and relative humidity [J]. Forest Products journal,1997,47(5):64-70.
[11]Todd F Shupe, Chung Y Hse, LeslieH Groom, Elvin T Choong. Effect of silvicultural practice and veneer grade lay up on some mechanical properties of loblolly pine LVL[J].Forest Products Journal,1997.47(9):63-69.
[12]Adym I,Colak S,Colakglu G, Salin E.A comparative study on some physical and mechanical properties of Laminated Veneer lumber(LVL)produced fromBeech(Fagus orientalis lipsky) and Eucalyptus(Eucalyptus camaldulensis Dehn) veneers [J]. Holzals Rohund Eerkstof,2004,62 (3):218-220.
[13]Wang Brad Jianhe,Dai Chunping. Hot-pressing stress graded aspen veneer forlaminated veneer lumber (LVL)[J]. Holzforschung,2005.59(1):10-17.
[14]赵丹,李晓秀,顾玉成等.单板厚度对杨木单板层积材强度性能的影响[J].林业科技,2001,26(2)：40-42.
[15]Hayashi Tomoyuki.Miyatake Atsushi Tensile strength properties of glued laminated wood and laminated veneer lumber with butt2joints [J].Zairyo/ Journal of the Society of Materials Science,2003,52 (4):341-346.
[16]Evangelos J Biblis. Edgewise flexural properties and modulus of rigidity of different sizes of southern pine LVL and plywood [J].Forest Products Journal,2001,51 (1):81-84.
[17]Stamm,AJ..Dimensional stabilization of wood by thermal reactions and formaldehyde cross-link, Tappi,1959a,42(1):39-44.
[18]Stamm,A.J..Dimensional stabilization of wood by catalysed heat treatment and cross-link, Tappi,19596,42(1):44-50.
[19]Lloyd.R.A.andA J.Stamm. Efect of resin treatment and compression upon the weathering properties of veneer laminates[J].Fo rest Prod.J., 1985,8(8):230-235.
[20]Ryu,J.Y. Takahashi,M.,Imamura,Y. and Sato,T. Biological resistance of phenol-resin treated wood.MokuzaiG akkaishi,1991,37(9):852-858.
[21]Ryu,J.Y,Ta kahashi,MJmamura,Y. and Kajita,H.Efect of molecular weight and some other properties of resins on the biological resistance of phenolic resin treated wood..Mokuzai Gakkaishi,1993,39(4):486-492.
[22]Ohmae,K.,Minato,K and Norimoto,M..The analysis of dimensional changes due to chemicaltreatments and water soaking for hinoki(Chamaecyparis obtusa) wood Holzforschung,56(l),98-102.
[23]Hui Wan, Moon G Kim. Impregnation of southern pine wood and strands with low molecular weight phenol-formaldehyde resins for stabilization of oriented strandboard.Wood and Fiber Science,2006,38(2):314-324.
[24]李凯夫,高振忠,孙瑾.21世纪初期我国人造板工业技术创新鱼议[J].林业科技开发,2001.15(1)：12-14.
[25]中田欣作、杉本英明、井上雅文.Development of compressed wood fasteners for timber construction Ⅲ.Bearing characteristics of compressed LVL plate with a drift-pin.木材学会志,2000,46(1).
[26]中田欣作、杉本英明、井上雅文.Development of compressed wood fasteners for timber constructionⅡ.Lateral resistance of drift-pin joints with compressed LVL plates in loading parallel to the grain,木材学志,1998,44(4)：247-254.
[27]中田欣作、杉本英明、井上雅文.Development of compressed wood fasteners for timber constructionⅢ.Bearing characteristics of compressed LVL plate with a drift-pin.木材学会志,2000,46(1)：37-46.
[28]中田欣作、杉本英明、井上雅文.Development of compressed wood fasteners for timber constructionⅣ.Moment resistance of a joint model with a compressed LVL plate and effect of reinforcement by glass fiber sheets,木材学会志,2000,46(3)：203-212.
[29]吴玉章,黑须博司,伊藤贵文.辊压预处理改善树脂浸注的均匀性[J].东北林业大学学报,2005,33(01)：23=24,40.
[30]钱俊,沈哲红,金永明,等.人工林杉木压缩整形过程中的定形工艺[J].木材工业,2005,19(4)：252-271.
[31]钱俊,叶良明,余肖红,等.速生杉木改性的研究—UF树脂浸渍后热压法改性[J].木材工业,2001,15(2)：142-161.
[32]钱俊,马灵飞,俞友明,楼永生.热压法制备速生杉木集成材工艺[J].林业科技开发,2005,19(05)：22-24.
[33]陈瑞英,刘景宏,魏萍.杉木间伐材压缩密化与回复变定的研究[J].福建林学院学报,2005,25(4)：294-298.
[34]陈瑞英,魏萍,刘景宏.压前含水率对杉木间材压缩木性能的影响[J].林产工业,2006,33(1)：102-131.
[35]魏新莉,向仕龙,何华.水热预处理对杨木压缩木物理力学性能的影响[J].木材工业,2004,18(3)：20-23.
[36]魏新莉,仕龙,何华.速生杨木热压处理的研究[J].木材加工机械,2004(2)：10-12
[37]陈桂华.泡桐单板条层积材工艺研究[J].林业科技.2006,31(1)：35-37.
[38]杜国兴.意杨单板层积材热压工艺研究[J].南京林业大学学报,1991,15(1)：58-63.
[39]徐咏兰.金菊婉,周晓燕.单板层积材喷蒸热压的初步探讨[J].林产工业,2000,27(4)：22-24.
[40]G E Troughton,C lum.Pilot plant evaluation of steam-injection pressing for LVL and plywood products[J].forest Products Journal,2000,50(l):25-28.
[41]韦益民,刘正添,郝丙业.杨木单板层积木一步和二步压制方法的比较[J].北京林业大学学报,1993,15(4)：112-117.
[42]于长海,吴晓龙.速生杨木单板层积材冷压工艺研究[J].林业科技,2002,27(3)：43-45.
[43]龙传文.脲醛树脂泡桐单板层积材的生产工艺[J].木材工业,19(1)：23-26.
[44]刘君良,张双保等.竹木复合单板层积材制备工艺[J].木材工业2005.19(5)：7-9.
[45]王卫东,王志强等.金属网增强型杨木单板层积材的研究[J].南京林业大学学报(自然科学),2003,11(6)：9-12.
[46]程丽美、黄慧、朱一辛.玻璃纤维增强杨木单板层积材弯曲性能的初步研究[J].江西林业科技.2008,(6)：54,62.
[47]王小青,郭莉,刘君良,张双保.竹木复合单板层积材制备工艺[J].木材工业,2005,19(05)：7-9.
[48]刘君良,王玉秋.酚醛树脂处理杨木、杉木尺寸稳定性分析[J].木材工业,2004,18(06)：5-8.
[49]鹿振友,刘艳,王淑娟.斜纹理对单板层积材力学性能的影响[J].中国木材,2003,(8)：24-25.
[50]徐咏兰,金菊婉.杉木小径材制造单板层积材技术的研究开发[J].林业科技开发,2001,15(2)：27-29.
[51]Chui,Y H,Schneider, MH, Zhang, HJ. Effects of resin impregnation and process parameters on some of poplar LVL[J]. Forest Products Journal,1994, 44(7):74-78.
[52]贺宏奎,常建民.三倍体毛白杨木材压缩密实化研究[J].木材加工机械,2006,(3)：24-27.
[53]张忠涛.我国的杨树资源与开发利用[J].林业建设,2001,5：21-24.
[54]张勤丽.我国意杨加工利用概况[J].林产工业,2000,27(5)：3-6.
[55]周宇.I-214杨木单板染色工艺的研究[C].杨树工业用材林加工利用与栽培论文集,2003：37-42.
[56]查朝生.营林措施对人工林杨树木材性质的影响[C].杨树工业用材林加工利用与栽培论文集,南京,2003：63-67.
[57]刘盛全.我国杨树人工林材性与加工利用研究现状及发展趋势[J].木材工业,1999,13(3)：14-16.
[58]李学新.浅谈杨树的适应性[N].中国绿色时报,2004,8(5).
[59]刘艳萍、陈志林、曾辉.杨木特性对其胶合板质量的影响及对策[J].河南林 业科技[J],2006,26(1)：29-30.
[60]马丽娜、付孝德、张明、汪文胜、刘盛全.人工林杨树木材密度变异规律的研究[J].安徽农业大学学报,2003,30(4)：410-413.
[61]Xu W, Steiner P R. A Statistical Characterization of the Ho rizontal Density Distribution in F lakeboard. Wood and Fiber Science,1995,27 (2):160-167.
[62]Dai C, Steiner P R. A nalysis and Implication of Structure in Short Fiber Wood Composites. Proceedings of the 2nd PacificRim Bio-based Composites Symposium.1994. V ancouver, Bc,Canada.
[63]Steiner P R, DaiC. Spatial Structure of Wood Composites in Relation to Processing and Performance Characteristics. Wood Sci.Technol.,1993 (28): 45-51.
[64]雷得定,吕斌.我国刨花板质量状况的评述[J].木材工业,1993,7(4)：36.
[65]Length C A. Investigations of F lakeboard M at Consolidation.Part I. Characterizing the Cellular Structure. Wood and Fiber Sci,1996,28 (2): 153-167.
[66]Suchsland O, Xu H. A Simulation of the HorizontalDensity D istributin in a F lakeboard. Fo rest P rod. J.,1989,39 (5):29-33.
[67]Such sland O, Xu H. Model A nalysis of F lakeboard V ariables.Forest Prod. J.,1991,41 (11,12):55-60.
[68]Lei Y K, et al. F racture Toughness of O riented F lakeboard.Wood Sci.,1980, 12(3):154-161.
[69]李大纲,吴雨飞,徐永吉.杨树木材pH值及其对脲醛树脂胶固化时间的影响[J].林产工业,1994,21(1)：12-14.
[70]相亚明.国产25种木材水浸提液的pH值和缓冲容量[J].木材工业,1987,(1)：16-23.
[71]叶克林.人工林杨树木材的加工利用[J].木材工业,2003,17(1)：5-7、10.
[72]陆从进.利用兴安落叶松小径原木高频胶合制造单板层积材的研究[J].林业科学,1988,24(4)：422-429.
[73]刘君良,江泽慧,孙家杰.酚醛树脂处理杨树木材物理力学性能测试[J].林业科学,2002,38(4)：176-180.
[74]北京造纸研究所等.北京地区七种杨木作为造纸原料的鉴定试验[R].全 国杨树良种普查鉴定会议资料选编,1976.
[75]Lloyd R A,Stamm A J1 Effect of resin treatment and compressionupon t he weat hering properties of veneer laminates [J]. ForestProd J,1985,8 (8):230-235.
[76]张占宽,刘君良.密实型杨木单板层积材的制造工艺及应用前景分析[J].林业机械与木工设备,2005,33(7)：152-171.
[77]沈德君,隋忠海,李杉.用杨木做复合地板的研究[J].辽宁林业科技.2008,(4)：43-44.
[78]方桂珍,崔永志,常德龙.多元羚酸类化合物对木材大压缩变形的固定作用[J].木材工业,1998,12(2)：16-19.
[79]方桂珍,李坚,刘一星.三聚氰胺—甲醛与木材的交联作用[J].林业科学,1997,33(3)：252-258.
[80]方桂珍,刘一星.低分子量MF树脂固定杨木压缩木回弹技术的初步研究[J].木材工业,1996,10(4)：18-21.
[81]方桂珍,李坚,孔漫,等.多元羧酸与木材酯化反应特征和交联反应参数[J].林业科学,1998,34(6)：93-97.
[82]方桂珍,崔永志,常德龙.多元羧酸类化合物对木材大压缩量变形的固定作用[J].木材工业,1998,12(2)：16-19.
[83]张云岭.低分子量三聚氰胺-甲醛树脂固定泡桐压缩木回弹的研究[J].木材工业,1996,10(6)：15-18.
[84]常德龙,陈玉和,胡伟华,卢春霞.用低分子树脂进行泡桐木材表面强化的研究[J].林产工业,1997,24(6)：7-10.
[85]刘君良,李坚,刘一星.PF预聚物处理固定木材压缩变形的机理[J].东北林业大学学报,2000,28(4)：16-20.
[86]刘君良,江泽慧,许忠允,沈德君,人工林软质木材表面密实化新技术[J].林产工业.2002,16(1)：20-22
[87]贺宏奎.速生杨木材压缩及树脂浸渍密实化研究[D].北京林业大学,2006.
[88]Schneider M H,Witt A E1 History of wood polymer composite commercialization [J]. Forest Product s Journal,2004,54(4):192-241.
[89]黄松军.强化杉木单板层积材工艺研究[D].北京.北京林业大学,2008.
[90]H.J.Zhang, Y.H.Chui, M.H. Schneider compression control and its significance in the manufacture and effects on properties of poplar LVL. Wood Science and Technology.1994,28,285-290.
[91]余先纯.PF树脂浸渍速生杉木的性能研究[J].林产工业,2008,(04)：38-40.
[92]吴玉章、松井宏昭、片冈厚.酚醛树脂对人工林杉木木材的浸注性及其改善的研究[J].林业科学,2003,39(6)：136-139.
[93]傅峰.功能人造板的新概念[J].建筑人造板,1994.2：19-23
[94]张建,王德江,刘兴龙.浅谈单板层积材.林业机械与木工设备[J].2002.30(2)：5-6
