Paint selection for printing boards

Primer types and film thicknesses. Primers include epoxy resin, polyester resin, acrylic resin and polyurethane resin. Primers are generally selected according to the purpose of the product base, the occasion of use, the degree of processing, and the matching of the topcoat. The film thickness of the primer is usually 5um.

1. Epoxy primer

It has good adhesion to the substrate, good water resistance, alkali resistance and chemical corrosion resistance. It is the earliest primer for coils, and its flexibility is not as good as other primers.

2. Polyester bottom

Good adhesion to the substrate, excellent flexibility, more sensitive to humid environments, chemical resistance is not as good as epoxy primer.

3. Water-soluble acrylic primer

Good adhesion to the substrate, excellent flexibility, low organic solvent content, low temperature curing, not suitable for storage in a humid environment, and high requirements for pretreatment.

4. Polyurethane primer

It has chemical resistance, friction resistance, durability and good flexibility.

Topcoat type and film thickness

The most commonly used topcoats are polyester, silicon modified polyester, polyvinyl chloride plastic sol and polyvinylidene fluoride.

1. Polyester

Good adhesion, wide range in formability and outdoor durability, moderate chemical resistance.

2. Silicon modified polyester

The hardness, wear resistance and heat resistance of the coating film are good, as well as good outdoor durability and non-chalking, limited gloss retention and flexibility, and medium to high cost.

3. Polyvinylidene chloride

It has good formability and color retention, excellent outdoor durability and chalking resistance, solvent resistance, limited color and expensive.

4. Polyvinyl chloride plastic sol

Excellent external durability and chemical resistance, damage resistance, beautiful appearance, and special primer is required. The surface can be smooth, used for compression or automatic shrinkage to form patterns. The coating thickness is generally greater than 100um. Except for plastic sol, in general, the coating thickness of primer and topcoat is > = 20um, and the performance of the product can achieve the predetermined purpose.