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zhangrobber(金币+300, 翻译EPI+1):辛苦了！谢谢！~~ 2010-11-06 22:09:41
A、The nature of the interface between coating and substrate has a great effect on the protection which provide by coating. So further study of coating / substrate interface is performed.
We find and construct mathematical models to show the relationship between coatings and substrate and the models can quickly predict the adhesion between the coating and substrate.
It has a strong theoretical significance and practical value on design and improvements of the coating formulation and enhance the protection coating on the substrate.
B、This article is based on wetting relationship between coating and substrate. We established thermodynamic models of the wetting rate and spreading in the process of painting of liquid paint.
Factors which have effect on the wet result such as the paint surface Gibbs energy, the substrate surface Gibbs energy as well as substrate surface roughness were discussed.
It is proved that the wetting ability and wetting degree of substrate are closely related with the surface Gibbs energy and roughness of substrate and coating liquid surface Gibbs energy . Gibbs energy derived substrate is conducive to the increase of the substrate coating process for wetting the surface.
When the substrate surface Gibbs energy is greater than the surface energy of the liquid coating, the wet process can be spontaneous. With the increase of the substrate surface roughness, wetting degree increased . In this condition , the spreading process may not necessarily be spontaneous.
C、This paper further studied factors which affected the adhesion between the coating and substrate. According to the established thermodynamic model of wetting, and method to improve the adhesion between substrate coated with metal, plastic substrate is discovered.
D、Take adhesion between Polyurethane coating and the metal substrate for example, focused on the impact of adhesion of the substrate roughness, substrate pretreatment, the number of polar functional groups of liquid coatings (incorporation of DMPA ) .
The results show that: the preparation on metal substrate surface (grinding, rust removal, degreasing, phosphating, sandblasting), an increase in the number of polar functional groups of coating formulations , the control of the ratio between soft and hard segments, and maintain certain paint viscosity play a significant role in improving the adhesion between coating and substrate .
E、Take Polypropylene plastic substrates for another example, focused on method to improve adhesion of plastic coatings and the plastic substrate ,
based on polypropylene plastic surface pretreatment (mechanical polishing, chemical oxidation), resins and solvent selection ,we got following conclusions through experiments: pretreatment on the surface of polypropylene plastic,the especially chemical oxidation pre-treatment can effectively improve the surface Gibbs energy,makes it much easier to wet the substrate coating.
The increase in substrate roughness can also effectively increase wetting degree, but when the roughness increases to certain value, it will affect the adhesion of coating on the substrate.
Because of the characteristics of polypropylene plastic, selected chlorinated polypropylene resin similar to its structure has a great adhesion.
When we take the modified chlorinated polypropylene or chlorine content of 25% isotactic chlorinated polypropylene as the plastic primer or adhesion promoter, the adhesion between the coating and the substrate is better.
Because of its high crystallinity, solvent resistance and other characteristics, Polypropylene plastic products makes the choice of solvent also much more difficult.
In this paper we selected a group of mixed organic solvents which can improve adhesion between the coating and the polypropylene plastic substrate. |
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