1. The concept of coating performance
The performance of the coating includes the performance of the coating product itself and the coating film. The performance of the coating product itself generally includes the performance that the coating should have before it is used and when it is used.
The performance that the paint should have before it is used, also known as the performance of the original state of the paint, represents the performance and quality of the paint in all aspects during the storage process as a commodity. The performance that the coating should have when it is used, also known as the construction performance of the coating, refers to the way of using the coating, the conditions of use, the conditions required for the formation of the coating film, and the performance of the coating in the process of forming the coating film.
The performance of the coating film is the performance that the coating film should have, and it is also the most important performance of the coating. The performance of the coating product itself is only to obtain the required coating film, and the coating film performance can express whether the coating meets the use requirements of the coated object, that is, the coating film performance indicates the decoration, protection and other functions of the coating. The performance of the coating film covers a wide range, depending on the requirements of the coated object, mainly including decoration, adhesion to the coated object, mechanical strength, resistance to external media and natural erosion, and self-aging damage.
2. Basis for coating analysis and testing
The performance of the coating means its use value, and it is comprehensive, wide-ranging and long-term use value. Coatings are used as decorative and protective materials. They belong to high polymer materials, but the coating itself is a semi-finished product, and the formed coating film is the high polymer material. Coating films are different from high polymer materials such as plastics, rubber, fibers, etc., and cannot exist independently. They need to be adhered to other objects to be coated to become materials. The different characteristics of polymer materials, the most important thing is that the coating film needs to adapt to the material performance requirements of the coated object and integrate with the substrate.
Paint is a material that serves the object to be coated and is applied to the surface of the object to be coated. Since the objects to be coated are diverse and the conditions of use are ever-changing, the coatings and coating films need to have the properties required by the objects to be coated, that is, the requirements of the objects to be coated are used as the basis for determining the performance of coatings and coating films.
The performance of coatings is based on the basic physical and chemical properties of coatings and coating films, but it is not comprehensive. The performance of coatings usually mentioned only shows a part of the basic properties of coatings and coating films.
3. Commonly used technical indicators for coating analysis and testing
The performance of coatings is multifaceted. In order to evaluate the performance of coatings, many test methods have been created and formulated over the years to examine the performance of coatings from different angles and aspects, and try to use numerical values to express them. These indicated values become the indicative values representing a certain aspect , that is, the technical indicators of the product. Combining the values stipulated by the main paint product technical indicators to express the performance of the paint constitutes the standard of the paint product. As a standard, it is unified, scientific, extensive, restrictive and feasible. The technical indicators are expressed by the measurement results of the specified detection methods. After a coating product is developed and produced, product standards must be formulated as the basis for product evaluation. For example, the inspection of architectural coatings is mainly based on GB/T9756-2009 "Synthetic Resin Emulsion Interior Wall Coatings", GB/T9755-2001 "Synthetic Resin Emulsion Exterior Wall Coatings", JC/T423-1991 "Water-Soluble Interior Wall Coatings" , JG/T3049-1998 "Putty for Building Interiors", JG/T157-2004 "Putty for Building Exterior Walls", JG/T24-2000 " Synthetic Resin Emulsion Sand Wall Architectural Coatings", GB18582-2009 "Interior Decoration Materials Limits of Hazardous Substances in Wall Coatings", GB18583-2008 "Limits of Hazardous Substances in Adhesives for Interior Decoration Materials" and related enterprise standards.
After years of practice, appropriate names are given to the properties of coatings to represent a certain aspect of coating properties. For example, the physical state of the coating has density, viscosity, etc.; the optical properties of the coating film have gloss, color, etc.; the mechanical properties include hardness, flexibility, etc. With the development of coating varieties, the specific items indicating the performance of coatings are gradually increasing, and the content of modern coating performance is gradually approaching the actual requirements of coatings.
