【作者】 韦双颖；

【导师】 顾继友；

【作者基本信息】 东北林业大学 ， 木材科学与技术， 2003， 硕士

【摘要】 目前胶合板厂大多采用无垫板装卸工艺，不平整的板坯及表板的翘曲变形妨碍了装板机的正常运行，所以板坯在进压机前必须先预压粘合成一体。由于目前胶合板生产普遍使用杨木单板做芯板，而杨木单板存在干燥后变形大（单板含水率普遍偏高）、吸水后膨胀率高（易造成芯板叠层离芯）、pH值偏弱碱性等问题[影响脲醛树脂（UF）胶凝胶化速度]，因此胶合板板坯的预压工艺对UF胶的初粘性提出了较高要求。另外，目前绝大部分人造板用于家具制造和室内装修上，而各类室内型人造板多使用UF树脂胶粘剂，因此普遍存在游离甲醛污染的问题。我国政府部门于2002年1月1日颁布了强制性标准GB18580—2001《室内装饰装修材料人造板及其制品甲醛释放限量》。为了适应新形势的发展，我国胶合板企业必须在生产工艺上和胶的制备上寻找新的出路。 本篇论文主要针对胶合板板坯，特别是杨木单板的预压问题进行了研究。通过单因素试验探讨，最终找到影响胶合板板坯预压的最主要因素——单板含水率。然后从单板中的水分入手，对UF树脂胶进行改性，从而使高含水率杨木单板的预压问题迎刃而解。在满足板坯预压性的同时胶合板的湿强度也必须达到国家标准。出于压制胶合板采用的是UF树脂胶粘剂，所以在试验过程中除了考虑其初粘性外，同时还要兼顾到贮存稳定性和甲醛释放量的研究。 用本次试验合成的UF胶粘剂压制胶合板，湿强度完全达到了国家标准要求，湿剪切强度≥0.7MPa；胶合板的游离甲醛释放量达到了同本JAS标准（农、林、渔部第920号通告，2000年6月28日最新修订）的Fc₀级，即平均值＜0.5mg／L，最大值＜0.7 mg／L；UF胶粘剂贮存期大于30d（20℃）。更多还原

【Abstract】 At present, no caul plate technology in the course of loader and unloader are used mostly in plywood factories. Because the veneers which are not flat and warp hinder the press loader regular running, the veneer must be glued to form one integral. Besides, plywood manufacture generally use polar veneer as core veneer, but because the following problem existed that polar veneer that moisture content was high distorted obviously after drying, thickness expansion rate of water absorbing was great and pH value of polar veneer was basicity, prepressing technology of veneer in plywood need higher tack of UF resin adhesive. At present, most of panels are used in furniture manufacture and indoor renovation and they are glued by UF resin adhesive, so formaldehyde emission problem exist generally. Nowadays, the’ state promulgated the standard, in order to adapt the development of new situation our plywood enterprises have to find a way in the aspect of production technology and manufacture of UF resin adhesive.This paper researched veneer (especially polar veneer) prepressing problem of plywood mainly. Through single factor experiments, we find finally the main factor thatinfluenced prepressing effect of plywood--moisture content of veneer. So aiming atmoisture of veneer, we added two modifying agents to UF resin adhesive, then this problem was resolved. At the same time prepressing property meet our needs, wet strength have to achieve the state standard. Because UF resin adhesive were used in plywood, storage life, formaldehyde emission and tack of it must be considered.Wet strength of plywood which were made with UF resin adhesive reached the state standard (more than 0.7MPa); formaldehyde emission meet the need of Fc0 level of JAS standard in Japan, namely average value is less than 0.5mg/L and maximum 0.7mg/L. Storage life of UF resin adhesive we made is longer than 30 days (20 ).更多还原