外墙涂装出现泛碱褪色,它对外观装饰效果具有极大的破坏性。大雨过后,涂料颜色往往发花、发白,严重的还会出现起皱,甚至是漆膜消失,这其实是外墙涂料泛碱的原因。
the exterior wall painting is fading with alkali, and it has great destructiveness to the exterior decoration effect. after the heavy rain, the color of the paints often becomes flower and white. serious wrinkles will appear, even the paint film will disappear. this is actually the reason why the exterior wall paint is alkaline.
如果基层和腻子层中含有大量未聚合的水泥或石灰,下雨时雨水会涌进腻子层和基层,天晴后水汽会把这些碱性物质带到涂层,在表面形成一层白色物质。同时因其高碱性导致涂层中颜料发生变色、褪色。
if a large amount of unpolymerized cement or lime is contained in the base and the putty, the rain will pour into the putty and the base, and the water vapor will bring these alkaline substances to the coating and form a layer of white material on the surface. at the same time, because of its high alkalinity, the pigment in the coating will change color and fade.
外墙涂料泛碱的解决方法
solving method of pan alkali in exterior wall coating
1、消除基层碱性主要是砂浆抹灰层的养护,可以浇水3-4次,使水泥完全聚合,则其碱性会很快下降。如果不具备浇水条件,靠自然雨水和自然聚合,则干燥的时间会更长,至少要20天以上(冬天可能要30天以上)因此,砂浆抹灰层的浇水养护是比较好的降碱方法。当然,水泥的选择也是很重要,选用合格达标的水泥是基础。
1, the elimination of basic alkali is mainly the maintenance of mortar plastering layer, can be watered for 3-4 times, so that the cement completely polymerized, its alkalinity will soon decline. if water conditions are not available, the drying time will be longer, at least for more than 20 days (or more than 30 days in winter). therefore, the water maintenance of the mortar plastering layer is a better method of reducing alkali. of course, the choice of cement is also very important. the selection of qualified cement is the foundation.
2、消除腻子层碱性主要是选用质量好的找平腻子,这种腻子不但硬度好且耐水,碱性不高(ph值小于10),关键是提高腻子中的粘合物(乳胶)用量,减少水泥用量,同时腻子施工好后要及时浇水1-2次,使腻子层中的水泥能完全聚合硬化,这样ph值也能降低。市场上有些低端腻子(1000元/吨以下的)完全靠水泥来提高粘结力,又没有及时淋雨养护,导致ph达到10以上(有的达14),这种情况肯定会出现泛碱。
2. to eliminate the alkalinity of the putty is mainly the selection of good leveling putty. this putty not only has good hardness and water resistance, but not high (ph value less than 10). the key is to improve the amount of adhesive (latex) in putty and reduce the amount of cement. at the same time, the putty should be poured in time 1-2 times after the putty is well constructed, so that the cement in the putty can be completely used. polymerization of hardening, so that the ph can also be reduced. on the market, some low-end putty (1000 yuan / tons below) completely rely on cement to improve the cohesive force, and no timely rain maintenance, resulting in ph up to 10 (some 14), this situation will certainly appear in the case of alkali.
3、选用封闭性好的底漆对基层和腻子层进行渗透封闭,使碱性物质难以随水汽渗透到涂层,这是种治标的方法。但如果底漆渗透封闭性不好或基层腻子碱性物质过多(ph>10),则还是会出现泛碱现象,要使底漆更好渗透,底漆乳液粒径要细,粘度要低。
3. choose a good primer to seal the base layer and putty layer, so that it is difficult for the alkaline material to permeate the coating with water vapor. this is a temporary solution. however, if the primer is not well sealed or the basic substance of the base putty is too much (ph>10), there will be a common alkali phenomenon. to make the primer better permeate the primer, the size of the primer is fine and the viscosity is low.