Finish for pre-coating coiled material

Abstract

The finish for pre-coating coiled material consists of saturated polyester resin with linear and / or branched chain structure and acid value less than 5 mg KOH / g 10-50 wt%, amino resin 1-30 wt%, polyisocyanate closed with at least two kinds of closing agent with active hydrogen 1-30 wt%, pigment slurry 40-87 wt% and assistant 0.1-5.0 wt%. It is homogeneous white ropy liquid mixture, and has coating-4 viscosity at 23 deg.c 20-200 sec and solid content 40-80 wt%. It is coated and stoved at 200-260 deg.c for 20-90 sec to form dry film of 8-35 micron thickness. The film can fulfill the requirement for pre-coating coiled material.

Description

technical field [0001] The invention relates to a topcoat for precoated coils. Background technique [0002] Since the pre-coated coil entered industrialization in the 1940s, its usage has continued to expand. Pre-coated coil coatings have also been continuously developed with the large number of applications of pre-coated coils, and their varieties have developed from a single variety to dozens of varieties at present. In different fields of use, the performance requirements for precoated coil coatings are also different. At present, the types of coatings used for pre-coated coil topcoats are mainly polyester coatings, and there are many varieties according to different application fields. European patent EP686678 discloses a precoated coil topcoat prepared with polyester resin, amino resin or urea-formaldehyde resin, catalyst, pigment, wax, polysiloxane, polyacrylic acid, etc., although a thickness of 40-55 μm can be obtained However, the curing temperature of this topc...

AI Technical Summary

Problems solved by technology

European patent EP686678 discloses a precoated coil topcoat prepared with polyester resin, amino resin or urea-formaldehyde resin, catalyst, pigment, wax, polysiloxane, polyacrylic acid, etc., although a thickness of 40-55 μm can be obtained However, the curing temperature of this topcoat is higher than 260 °C, and the paint film cannot be completely cured in the oven that usually produces pre-coated coils.