Application method of epoxy modified polyester resin in synthesis of precoated metal coil coating primer

Abstract

The invention discloses an application method of epoxy modified polyester resin in synthesis of a precoated metal coil coating primer. The application method comprises the following steps: firstly, synthesizing the epoxy modified polyester resin; secondly, preparing the epoxy modified polyester resin into a finished paint. The method is characterized in that polyester resin is subjected to epoxy modification; then epoxy modified polyester resin is used as a base stock for preparing the precoated metal coil coating primer; epoxy resin and the polyester resin undergo grafting reaction to obtainthe epoxy modified polyester resin. Therefore, the epoxy modified polyester resin has better properties such as adhesion, flexibility, boiling water resistance and damp and heat resistance than thoseof a primer prepared with a mixing method; under the condition of ensuring the hardness of a paint film, the flexibility is remarkably improved and the T bending performance is improved; meanwhile, the cross-linking density is increased, and the corrosion resistance is enhanced; by using the epoxy modified polyester resin, production procedures of the coating can be reduced, and the species of added raw materials are reduced, so that the production and control cost can be reduced, the interbatch stability is increased and the mass risk is reduced.

Description

Technical field [0001] The invention relates to the technical field of the synthesis of primers for pre-coated metal coils, in particular to an application method of epoxy modified polyester resin in the synthesis of primers for pre-coated metal coils. Background technique [0002] At present, epoxy resin is widely used in pre-coated metal coil coating primer, and the epoxy resin used in epoxy primer is based on bisphenol A type E-06 or E-03, formed by epoxy resin coating The coating film has chemical bonds and polar groups that cannot be destroyed by corrosive media, so it has excellent chemical resistance. At the same time, the cross-linked epoxy resin paint film contains many hydroxyl and ether bonds, so it has strong extremes with the substrate. Sexual binding force has a shielding effect on corrosive media, and can passivate the protected metal, play a corrosion inhibitor and electrochemical effect, but its flexibility is poor. [0003] Polyester primer is also a kind of prim...

AI Technical Summary

Problems solved by technology

At present, the technology of adding epoxy resin after polyester resin is widely used, that is, a part of epoxy resin is combined in the production stage of polyester resin coating to achieve the purpose of increasing adhesion, improving hardness, and increasing corrosion resistance. Contains a lot of hydroxyl groups, epoxy groups and ether bonds, so it has strong adhesion to the substrate, and its chemical resistance is excellent, such as alkali resistance, salt spray resistance, etc. Therefore, ordinary pre-coated coil primers Generally, a mixture of polyester resin and epoxy resin is used, that is, these two components are added to the coating formula respectively, so that the primer has the characteristics of polyester and epoxy at the same time, but the matching performance of this system is general, and in the actual use process Among them, there are many problems in adding epoxy resin to cold merging, such as the decline of T-bend performance after merging, poor flexibility, fluctuations in the amount added between batches, and obvious stratification in storage, etc.

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