Insulating Glass Desiccant
干燥剂对中空玻璃非常重要，直接决定着中空玻璃的美观和使用寿命。中空玻璃干燥剂作用如下：
1）吸附掉生产时密封于中空玻璃空气层内的水分；
2）在中空玻璃寿命期内连续吸附进入空气层内的水分，以保持中空玻璃内的低露点（至少-40℃）；
3）吸附掉生产时密封于空气层内的挥发性有机溶质，以及中空玻璃寿命期内进入空气层内的有机溶质。
远影中空玻璃干燥剂由凹凸棒粘土经过特殊工艺制成，是专门为中空玻璃研制的，考虑了中空玻璃使用过程中各种情况，具有无可比拟的优点：
1）自身的含水量低，远影产品包装水含量控制在1.0%以内，远低于行业内1.5%的平均水平。
2）深度吸附能力强，能充分吸收玻璃夹层中的水分，保证中空玻璃的低露点。
3）基本不吸附氧气、氮气和惰性气体，保证中空玻璃不发生内挠和外挠，延长中空玻璃使用寿命。
凹凸棒石具有选择性吸附能力，它的表面有大量的负电性OH-，呈极性，对极性分子H2O极易吸附，对非极性分子的惰性气体、N2、O2不吸附。经上海化工研究院检测，用纳米凹凸棒石粘土生产的远影中空玻璃干燥剂氮气吸附量<0.53mg/g，3A分子筛氮气吸附量<2mg/g。如果用4A分子筛做中空玻璃干燥剂，在吸附水气的同时还吸附氮气、氧气和惰性气体，会引起玻璃夹层负压，从引起玻璃内挠；若温度升高，4A分子筛又会解吸，释放出气体，引起玻璃夹层正压，导致玻璃外挠。这样内挠外挠不断交替作用，会使密封胶失效，中空玻璃就失去了作用。
4）强度好，不开裂；粉尘少，不落粉。凹凸棒石则具有较高的粘结性，烧结后强度高，磨耗低，粉尘低。
5）对铝合金框架和密封条无腐蚀作用。
6）能吸附玻璃夹层内的挥发性有机溶质。
凹凸棒石纤维状会部分搭成少量较大的孔道，再加上凹凸棒石对有机物的选择性吸附能力强，因此能吸掉密封胶中含有的少量挥发性有机溶剂。几年来的实践证明，使用远影牌中空玻璃干燥剂生产的中空玻璃还没有出现有机雾的现象。
7）静态水初始吸附速度慢。这种情况对中空玻璃是有利的，初始吸附量小，剩余吸附量就大，可以延长中空玻璃使用寿命。
8）温升大，温升放气量小。中空玻璃干燥剂则升温趋势一直是平衡的，这种性质使得凹凸棒石更有优势。一般来说，如果放气量合格，温升越高，表明干燥剂越好。
Yuanying insulating glass desiccant is made of attapulgite clay through special technology, and is specially developed for insulating glass, considering all kinds of situation among the using process of insulating glass. Insulating glass desiccant has the following function:
1) Adsorbing the moisture in glass interlayer, the moisture comes from production period;
2) Adsorbing the moisture which enters insulating glass among its life period, to keep low dew point in insulating glass;
3) Adsorbing volatile organic solutes in glass interlayer, organic solutes come from production period and use period.
Attapulgite has the ability of selective adsorption, and its surface has a large number of electronegativity OH-, showing polarity. It is easy to adsorb polar molecule H2O and is very difficult to adsorb nonpolar molecules such as N2, O2, inert gases. Tested by Shanghai Research Institute of Chemical Industry, nitrogen adsorption capacity of insulating glass desiccant is less than 0.53 mg/g, and nitrogen adsorption capacity of 3A molecular sieve is less than 2 mg/g. If 4A molecular sieve used as insulating glass desiccant, it adsorbs H2O at the same time will adsorb N2, O2, inert gases, this will cause glass interlayer negative pressure and occur introflexion; If the temperature increases, 4A molecular sieves will desorb and release gases, cause glass interlayer positive pressure and excurvature. Thus continue alternating roles, sealant will lose effectiveness and insulating glass will become invalid.
Attapulgite fibres partly will build into a small amount of large channels, plus its strong selective adsorption ability of organic solutes, therefore can absorb a small amount of volatile organic solvents in the sealant. Over the past few years of practices has proved that using Yuanying desiccant to produce insulating glass there is no phenomenon of organic fog.
Yuanying Insulating Glass Desiccant has the incomparable advantages:
1) Its moisture content is low. Yuanying moisture in packing is controlled within 1%, far below the average level 1.5% of this industry.
2) Depth absorption ability is strong, can fully absorb moisture in insulating glass, ensuring low dew point of insulating glass.
3) Insulating glass desiccant almost doesn’t adsorb O2, N2 and inert gases, so it can ensure that insulating glass doesn’t occur introflexion and excurvature, prolong the service life of insulating glass.
4) Good strength, no cracking; less dust, not falling powder. Attapulgite has good caking property, after sintering it has high strength, little dust, low attrition rate.
5) Non-corrosive effect to aluminum alloy frame and sealing strip.
6) Insulating glass desiccant can adsorb volatile organic solutes in glass interlayer.
7) The initial static water adsorption speed is slow. This kind of circumstance is good for insulating glass, the initial adsorption quantity is small, the residual adsorption quantity is big, can prolong the service life of insulating glass.
8) Large temperature rise, releasing small amount of gas. The warming trend of insulating glass desiccant has been to balance, and this makes the attapulgite more advantages. In general, if the volume of releasing gas is qualified, the higher temperature rises, the better desiccant is.
