棉秆中密度纤维板工艺技术的研究

探讨以棉秆为原料生产中密度纤维板的主要生产工艺参数.试验结果表明,在板材密度0.7 g/cm3、施胶量12%、防水剂1.5%、热压温度180℃、热压时间15 s/mm的最佳工艺条件下,棉秆中密度纤维板的各项力学性能均超过国家标准要求,但24 h吸水厚度膨胀率未达标,可能与棉秆原料自身特点有关.     

中纤板热压机微机测控系统的研究

采用单片机与台式微机结合构成中纤板热压机微机测控系统，用MCS-51汇编语言和基于Windows98的Visual Basic6.0分别编写单片机数据采集与控制程序和微机主控程序，具有数据处理能力强、数据存储量大、操作界面直观方便等优点。系统设计中考虑了系统的可扩展性和通用性，便于系统扩展和移植。     

刨切薄竹贴面中密度纤维板工艺研究

对刨切薄竹贴面中密度纤维板(MDF)的工艺进行了研究,结果表明:在MDF的上下表面直接粘贴刨切薄竹的工艺可行,并根据试验结果确定了较优的贴面工艺参数.测试结果还显示,刨切薄竹背衬无纺布后再与MDF胶合,其表面胶合强度比刨切薄竹直接贴面MDF时低.     

MDF管道与搅拌联合施胶新工艺试验

在中密度纤维板生产过程中采用管道与搅拌联合施胶新工艺，可以有效地解决产品表面存在的胶斑问题。试验表明，管道施胶部分比例达到４５％－５５％可以取得预期的效果，产品力学性能还有所提高，而胶耗量比传统的管道施胶有明显的减少。     

Gas permeability of fiberboard mats as a function of density and fiber size

ABSTRACT

Gas permeability and structure of fiberboard mats are essential properties because of their impact on mat internal gas pressure, moisture content and temperature evolution during the hot-pressing process. The objectives of this work were to determine the effect of fiber size and mat density on the intrinsic gas permeability of the mat. For the study of these mat properties, panels with a homogeneous density profile through the thickness were manufactured at five density levels (200, 400, 600, 800 and 1000?kg m^?3) for three different fiber sizes. Fiber refining was performed in a disk refiner at three plate spacings. Gas permeability was measured with an in-house built apparatus. The results showed that the fiber sizes studied had no significant effect on the intrinsic permeability. This was likely due to a more significant impact of the internal porous structure of the mat compared to fiber size. Besides, the intrinsic permeability decreased significantly when the panel density increased from 198 to 810?kg m^?3. This suggests that the decrease of the intrinsic gas permeability during the last seconds of press closure plays an essential role in the bulk moisture mass transfer through the fiberboard mat.     

Utilisation of wood biomass residues from fruit tree branches,evergreen hardwood shrubs and Greek fir wood as raw materials for particleboard production. Part A. Mechanical properties

This paper investigates the potential of utilising wood biomass from fruit tree branches and evergreen hardwood shrubs as raw materials in the production of particleboards when mixed with Greek fir wood particles. The main mechanical properties of the boards made therefrom were determined and compared with those made of typical industrial wood (IW) particles. The highest modulus of rupture and elasticity (30.0 N/mm² and 4330 N/mm², respectively) in bending and screw withdrawal (SW) resistance (127.8 N/mm) were reported for boards made of Greek fir and were downgraded when the fruit tree branches or evergreen hardwood shrub particles also participated. The participation of fruit tree branch particles in proportions higher than 50% improved the internal bond (IB) of fir produced boards, while the highest IB strength (0.95 N/mm²) was reported for boards made of fruit tree branches. Particleboards made of evergreen hardwood shrubs showed inferior mechanical properties compared with those made of IW particles. The latter also showed superior bending strength but inferior SW resistance compared with boards made of fruit tree branches. Hygroscopic and other properties are under determination and will be presented and discussed in the second part of the work.