彩涂板的背面漆起什么作用

彩涂板对背面漆的要求不高,但是相对于底漆,彩涂板它还是有一定的耐候性和柔韧性要求。背面漆涂在卷材的背面,主要起保护作用,同时提供外观性和一定的耐久性。要求漆膜有良好的防腐蚀性、抗划伤性、抗粘连性和加工性,但没有装饰性和户外耐久性方面的要求常用的背面漆有环氧型、醇酸型、聚酯型三种。前两种因为耐久性较差的原因,现已大部分的面的不涂底涂装5μm的底漆后再涂装背面漆。从施工和使用上划分,可将背漆分成三类漆,也可以

(1)防蚀性能要求较高的,彩涂板基板背面涂层结构为底漆加背漆。此时的背漆主要起遮挡保护作用,可与彩涂板面漆用同一品种,但性能要求比面漆低,只要求抗划伤性、抗粘连性和加工性符合要求。从经济考虑一般可用氨基醇酸树脂类作为背漆的成膜树脂,如豆油改性短油度醇酸树脂和三聚氰胺树脂背漆。物气血
(2)基板背面不涂底漆只涂一道背漆。此时它起着底漆和背漆的双重作用,除背漆的抗划伤性、抗粘连性和加工性外,还必须具有良好的防腐蚀性能。成膜物质一般可用环一氨基、环氧一聚酯和聚酯一聚氨酯等。为提高背漆的防腐蚀性,除着色颜料外,在涂中还需加入防腐蚀颜料。

(3)当预涂金属卷材主要用来制备泡沫夹心板时,背漆除要求对底漆或基板有良好附着力和力学性能外,还必须适应夹心板的制造工艺。例如对直接注料发泡工艺,要求漆对发泡材料有好的黏附性;对泡沫芯板粘贴工艺,由要求背漆与所用黏合剂相匹配。膜物一般可用环氧一聚酯或聚酯一聚氨酯。

The requirement of color coated board for back paint is not high, but compared with primer, it still has certain weather resistance and flexibility requirements. The back paint is applied on the back of the coil, mainly for protection, while providing appearance and certain durability. The film is required to have good corrosion resistance, scratch resistance, adhesion resistance and processability, but there are no requirements for decoration and outdoor durability. The commonly used back coatings are epoxy type, alkyd type and polyester type. Because of the poor durability of the first two kinds, most of the surfaces are not primed, and then coated with 5 μ m primer. From the construction and use of the division, can be divided into three types of back paint, can also be used
(1) The coating structure on the back of the substrate is Primer Plus back paint for the substrate with high corrosion resistance. At this time, the back paint mainly plays the role of shielding protection, and can be used with the same variety as the top paint, but the performance requirements are lower than the top paint, only the scratch resistance, adhesion resistance and processability are required to meet the requirements. Generally, amino alkyd resin can be used as film-forming resin for back paint, such as soybean oil modified short oil alkyd resin and melamine resin back paint. Qi and blood
(2) There is no primer on the back of the substrate, only one coat of back paint. At this time, it plays a double role of primer and back paint. In addition to scratch resistance, adhesion resistance and processability of back paint, it must also have good corrosion resistance. Generally, the film-forming materials can be ring amino, epoxy polyester and polyester polyurethane. In order to improve the corrosion resistance of the back paint, in addition to coloring pigments, anti-corrosion pigments should be added in the coating.
(3) when the pre coated metal coils are mainly used to prepare foam sandwich panels, the backing paint must also be adapted to the manufacturing process of the sandwich panels in addition to requiring good adhesion and mechanical properties to primers or substrates. For example, direct injection foaming process requires good adhesion of lacquer to foamed materials, and the bonding process of foam core should be matched with the binder used. The film can be made of epoxy polyester or polyester polyurethane.