Development of lightweight wood-cement composite board using microballoon of fine pulvernized volcanic glass(micro-Shirasu-balloons)

为了制备轻质木材水泥复合板，将不同比例的白炭黑微球掺入到水泥刨花板中。预计气球的加入不仅会使它们更轻，而且还会改善一些性能。因为气球是火山玻璃细粉燃烧的产物，具有很低的密度、低导热性、低吸湿性、高熔点、高耐热性和不燃性。测试用板在如下条件下以混合比制成：水泥/木屑比（木材比）：2.0，2.5气球/水泥比（气球比）：0- 0.5目标密度：0.6-1.2板尺寸：350 × 350 × 15 mm从物理测试和观察制成的板的结果总结如下：（1）在较高的气球比下，在木材比为2.5的较高密度板中不能控制目标厚度。（2）板材的表面状况得到明显改善，尤其是低密度板材。（3）密度在0.8以上的板材，在较低的气囊比（0.1和0.2）下，弯曲性能和内部结合质量得到改善。即使密度为0.8的板在弯曲强度方面也满足JIS高密度水泥刨花板的要求。但是，这些性能下降，在板的气球比小于0.2。（4）当气泡率大于0.1时，板材24 h浸水后的厚度膨胀率显著降低，尤其是高密度板材。（5）在密度为1.2的板中，在气囊比为0.3或更大时，以及在密度为1.0和0.8的板中，在气囊比为0.2或更大时，可以看出导热率降低了5至10%。（6）所有试验用板都显示出高耐火性，并满足内部装饰材料的JIS不燃性等级2的要求。

In order to make lightweight wood-cement composite board, various parts of micro-Shirasu-balloon were mixed into cement-bonded particleboard. It was expected that the addition of the balloon would not only make them lighter, but also improve some properties. Because the balloon is the burning product from fine pulvernized volcanic glass and possesses very low density, low thermal conductivity, low hygroscopicity, highly melting point, highly heat resistance and incombustibility. Boards for test were made at the mixture ratio under the conditions as follows :Cement/wood chip ratio(Wood ratio) : 2.0,2.5Balloon/cement ratio(Balloon ratio) : 0-0.5Target density : 0.6-1.2 Board size : 350x350x15mmResults were summarized from physical tests and observation of the boards made as follows :(1)Target thickness could not be controlled in higher density board of the wood ratio of 2.5 at higher Balloon ratio.(2)Surface condition of the boards was improved remarkably, especially in lower density boards.(3)Bending properties and internal bond quality were improved in the boards of the density of 0.8 and more at lower ballon ratio of 0.1 and 0.2. Even the board with the density of 0.8 met the requirements of JIS of High Density Cement-Bonded Particleboard in bending strength. But, those properties decreased in the boards of the balloon ratio less than 0.2.(4)Thickness swelling after 24h soaking test was reduced remarkably in the boards at the balloon ratio of 0.1 and more, especially in higher density boards.(5)Five to ten percentile reduction of thermal conductivity was recognized in the boards of the density of 1.2 at the balloon ratio 0.3 and more, and of the density of 1.0 and 0.8 at the balloon ratio 0.2 and more.(6)All of the boards for test showed high fire resistance and met the requirements of the JIS incombustibility grade 2 of Internal Finish Material.