來源:http://www.guangshe.com.cn/ 發(fā)布時間:2021-07-29
鋁卷在成卷之前,需要做一些預處理工段,以保證鋁卷表面的清潔。以免其表面存在殘留的油脂及潤滑劑,對涂裝及使用產(chǎn)生影響。所以,鋁卷在成型前要對它進行以下幾個方面的額預處理。
Before the aluminum coil is rolled, some pretreatment sections need to be done to ensure the cleanness of the surface of the aluminum coil. To avoid residual grease and lubricant on the surface, which will affect the coating and use. Therefore, the aluminum coil should be pretreated in the following aspects before forming.
一,可以使用熱水對鋁卷進行清洗。熱水清洗主要是將基板表面殘留的脫脂劑清洗干凈,保證這些殘留物能溶解其中,以防這些脫脂劑對基板造成二次污染。使用方式多為浸洗和噴淋刷洗的方式。所用水質(zhì)硬度不要太高,否則,水中的礦物質(zhì)會在基板表面生成礦斑。
1、 Hot water can be used to clean the aluminum coil. Hot water cleaning is mainly to clean the residual degreasing agent on the surface of the substrate to ensure that these residues can be dissolved, so as to prevent these degreasing agents from causing secondary pollution to the substrate. The use methods are mostly immersion washing and spray brushing. The hardness of the water used should not be too high, otherwise the minerals in the water will form mineral spots on the surface of the substrate.
二,熱堿脫脂由于預涂線線速較快,所以所用的脫脂劑一般濃度較高,典型的脫脂劑含有氫氧化鈉(NaOH)、碳酸鈉(Na2Co3)、水玻璃(Na2SiO3)、磷酸鹽等組份。熱堿脫脂工序一般分兩步處理以確保鋁卷基板表面清洗干凈,且多用噴淋刷洗的方式。
2、 Due to the fast line speed of precoating, the degreaser used for hot alkali degreasing generally has a high concentration. The typical degreaser contains sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium silicate (Na2SiO3), phosphate and other components. The hot alkali degreasing process is generally divided into two steps to ensure that the surface of aluminum coil substrate is cleaned, and spray brushing is often used.
三,對它進行鈍化處理。鈍化處理是通過加壓噴淋、浸涂或輥涂等方式使鈍化劑在基材表面形成轉(zhuǎn)化膜。一般使用加壓噴淋的方式,鈍化液在使用過程中產(chǎn)生的泥渣往往會堵塞噴孔,從而影響噴淋得效果。
3、 Passivate it. Passivation treatment is to form a conversion film on the surface of the substrate by means of pressurized spraying, dip coating or roll coating. Generally, pressurized spraying is used. The sludge generated during the use of passivation liquid often blocks the spray hole, thus affecting the spraying effect.
浸涂的方式雖然解決了這一問題,但鈍化液的消耗量較大。以上兩種方法在實際操作中都需要用水沖洗多余的鈍化液,就會產(chǎn)生廢水的回收和凈化問題,輥涂是鈍化施工方式,具有涂布均勻、經(jīng)濟實用、不需淋洗等優(yōu)點。鋁板一般采用鉻酸鹽/氧化物型處理劑,該類處理劑含有鉻酸鹽、鉻酸、磷酸及促進劑氟化物和鉬酸鹽。該類處理劑必須加入磷酸,否則就不能用來處理食品和飲料用鋁板。
Although dip coating solves this problem, the consumption of passivation solution is large. In practice, the above two methods need to wash the excess passivation solution with water, which will produce the problem of wastewater recovery and purification. Roll coating is a passivation construction method, which has the advantages of uniform coating, economy and practicality, no leaching and so on. Chromate / oxide treatment agent is generally used for aluminum plate, which contains chromate, chromic acid, phosphoric acid and accelerator fluoride and molybdate. This kind of treatment agent must be added with phosphoric acid, otherwise it can not be used to treat aluminum plates for food and beverage.