双面覆膜等厚高强竹胶合板相关生产工艺的研究

【作者】 周靖；

【导师】 韩健；

【作者基本信息】 中南林学院 ， 木材科学与技术， 2003， 硕士

【摘要】 随着国民经济建设的发展和人民生活水平的日益提高，市场对各种人造板材的需求量越来越大，而我国是一个木材资源相对较小的国家，森林覆盖率仅为16.55％，远不及发展中国家的平均水严。为此，国家科委和建设部制定和调整了研究开发方向，探讨利用我国资源丰富的竹材来制作竹胶合板满足建筑、汽车制造、包装、家具、装饰、集装箱制造等工业领域的需求。竹胶合板作为一种新型人造板投放市场已十多年的历史，它主要用作混凝土浇注工程模板，同时也可用作汽车、火车的车厢底板、集装箱底板等。 竹材生产周期短，再生能力强，我国的资源十分丰富，因此竹材人造板是一种很有发展前景的人造板材。目前，竹胶合板的生产一般采用“冷进-冷出”工艺，此工艺虽然具有一定的优势，但也存在一些突出的缺陷，如热压周期长、生产效率低、能耗水耗大等。为此，人们尝试采用“热进-热出”工艺进行生产，但这种工艺又存在着产品表面变形较大、表面平整度光亮度不高、卸板时容易产生鼓泡和皱褶等现象。 本课题研究的目的是为了有效地解决“热进-热出”工艺存在的缺陷，研制一种适合“热进-热出”工艺生产的中温固化型酚醛树脂以及相应的热压工艺。本研究通过提高初期酚醛树脂的聚合度、调整甲醛、烧碱与苯酚的摩尔比以及添加一定量的促进剂来达到加快树脂的固化速度、降低固化温度的目的，进而实现树脂的中温固化。实验通过控制合成时树脂的粘度来决定其反应的终点，并通过正交实验设计，分析不同因素对合成酚醛树脂在105～115℃条件下固化的影响，对实验数据进行统计分析，确定了中温固化型酚醛树脂的最优配方和制备工艺，并通过重复实验验证了结果的可靠性。实验表明苯酚：甲醛：氢氧化钠：水的摩尔比为1：1.75：0.4：11.5；促进剂的加入量为苯酚质量的4％；树脂粘度为360～420s(加水前)时，树脂能实现中温固化。竹胶合板用表面复木的竹木复合材料作为基材，解决普通竹胶合板基材硬度高难以进行砂光处理的问题，基材表面所用木质单板的厚度以3.0mm较为适宜，单板的单面涂胶量为100g/m~2左右。采用三段卸压方式对基材热压，通过实验分析确定主要热压工艺参数。实验表明基材热压温度为105～115℃，热压压力为2.8MPa，高压阶段的保压时间为60s/mm板厚，竹帘含水率12～18％时的工艺条件为最优工艺。基材经等厚砂光处理后，再进行贴面处理，贴面材料为酚醛树脂浸渍纸。贴面时，浸渍纸的数量根据实际需要确定，可以是一张，也可以是几张。经实验优化选择后的最佳贴面工艺参数为：热压温度140～145℃，热压时间3.5～4min，最大热压工作压力2.8MPa，胶膜纸挥发分含量6～10％。 酚醛树脂在中温条件下迅速固化，给竹胶合板生产实现“热进-热出”工艺打下了良好 双面覆膜等厚高强竹胶合板相关生产工艺的研究的基础。生产中由于热压温度降低，因此可以减少热压时的能耗，使生产成本减少。通过砂光等厚处理，解决了目前普通竹胶合板产品厚度公差大、表面质量差、胶层脆性大、易开胶等缺陷，使竹胶合板质量上了一个新的台阶，从而拓宽了它的使用范围。采用“热进热出”生产工艺，解决了目前普通竹胶合板“冷进冷出”工艺热压周期长＼生产效率低、耗水、耗电、耗气量大的问题，并使目前普通竹胶合板生产线的生产能力提高了一倍以上。竹材人造板以竹材为主要生产原料，充分发挥了我国的竹材资源优势，而且生产工艺简单、投资规模不大，建设周期短，产品适用范围广，因此具有良好的市场前景，其经济效益。社会效益和生态效益都是十分明显的。更多还原

【Abstract】 With the development of national economy and the improvement of standard of living of people increasingly demand in market for every kind of artificial plywood is larger. But our country lumber resource is relatively lesser and forest overlay rate is only 16.55%, which is far less than the average level of developing country. Therefore national science committee and construct ministry set down and regulate research direction, they think that whether we can use our resourceful bamboo to produce bamboo plywood which meets demand for the industry section of constructing, automobile manufacture, packing, decorating, furniture and container manufacture. It has been more than ten years history since bamboo plywood as new artificial plywood come into market for the first time. It is used for the concrete-mould plywood and the railway motherboard or container motherboard.Bamboo has the short growth cycle, and the rebirth ability is strong. The resource in china is very abundant, therefore the bamboo plywood is full of the developing respect. Presently in the production of bamboo plywood we commonly adopt the cold technology which has some advantages but exists some outstanding shortcomings such as the long yielding period, the low efficiency and the large consumption of water and energy. Therefore some people attempt to adopt the heat technology. But this technology has the phenomena on the surface of product such as the large transformation, the low flatness and brightness, drumming easily and rumple.To solve effectively the shortcoming of the heat technology I prepare to study a kind of mid-temperature phenol formaldehyde adhesive that suits for the heat technology and the heat -pressing method correspondingly. The adhesive can cure rapidly and avail to the demand of mid-temperature curing because of its low curing temperature by the way of elevating the rate of polymerization in PF resin , adjusting the mol-ratio of formaldehyde, NaOH and phenol and also adding a little accelerant. I can determine end-point of its reaction in the course of experiment through controlling the viscosity of resin. After dealing with statistically experimental data I analysis the curing influence of the different factors to PF resin at the 105-115℃,and ascertain the most excellent prescription and yielding craftwork. At last I validate the reliability through repeated experiment. Experiment present that when the mol-ratio of phenol: formaldehyde:NaOH:H2o is the ratio of 1:1.75:0.4:11.5 ,and the quantity of accelerant is fourpercent of the quantity of phenol, the viscosity is 360-420 seconds the resin can cure at the mid-temperature.Bamboo plywood use one or two wooden-boards covering the surface of motherboard , which can solve the problem of milling difficulty because bamboo’s rigidity is great. The feasible thickness of wooden-board ought to be 3.0mm and its glue quantity is 100g/m2 or so. The pressure divided to three sections is unloaded. Also technology parameter is decided by experimental analysis. Experiment present that when the heat pressing temperature on the motherboard is 105-115℃,the pressure is 2.8Mpa,and the time holding pressure in high pressing stage equal to 60s/mm.and the rate of moisture in the bamboo motherboard is 12-18% the technical parameter is the most excellent. After milling surface motherboard is plastered with the PF dipped paper that may be one or two ones depending on need. The most excellent technical parameter in term of experiment is heat pressing temperature 140-145℃, the time of heat pressing 3.5-4min, the largest pressure 2.8Mpa,and volatilization content of dipping paper 6-10%.PF resin can cure rapidly at the mid-temperature, as establishes favorable conditions that adopt the heat technology in the production of bamboo plywood. Because heat pressing temperature is low consumption of energy can be decreased, also produce cost can be reduced. Milled motherboard can resolve many problems such as the larger thickness tolerance on the surface of general bamboo plywood presently, the l更多还原