In paints, the solid content refers to the portion of the coating component that becomes the coating film after the coating film has dried. It is expressed as the ratio of the remaining mass of the coating after heating and baking at a certain temperature to the initial mass of the sample.
After the coating is formed into a film, what evaporates is the solvent, thinner, and some additives in the coating. The rest are the resins, pigments, fillers, and similar non-volatile components in the paint. Therefore, the solids content is also called the non-volatile content. The higher the solids content of the paint, the thicker the initial film will be when painted. That is, to achieve the same dry film thickness, a coating with a higher solids content consumes less coating than a coating with a lower solids content. Therefore, when choosing a type of paint, it is generally more economical to choose a paint with a higher solids content.
The solid content of the paint can determine the effective utilization rate of the paint and the content of the agent, and can also determine the environmental protection performance of the paint. The solid content of the paint is an important performance index of solvent-based paint.
The solid content of coatings is usually measured by the oven method. The oven method can be further divided into the Petri dish method and the watch glass method. The detection standards of different countries are slightly different, but the basic principles are the same. The method used is to heat and bake the paint at a certain temperature and compare the amount of substance remaining after the paint dries with the original mass of the sample.
In this regard, the "ISO 3251 Paints and varnishes - Determination of volatile and non-volatile substances" standard developed by the International Standards Organization (ISO) is complied with.
This document specifies a method for determining the non-volatile matter content, by mass, of paints, varnishes, paint and varnish binders, polymer dispersions and condensation resins such as phenolic resins (resols, novolac solutions, etc.). This standard describes a method that is also valid for formulated dispersions containing fillers, pigments and other auxiliaries (e.g. thickeners, film-forming agents).
The non-volatile matter content of a product is not an absolute quantity, but depends on the temperature and heating time used for determination. Consequently, when this method is used, only relative and fictitious values for the non-volatile matter content are obtained due to solvent retention, thermal decomposition, and evaporation of low molecular weight components. Therefore, the method is primarily designed for testing different batches of the same type of product.
This method is suitable for synthetic rubber cages if heating for a certain period of time is considered appropriate.
In-house methods for determining non-volatile matter usually involve drying with infrared or microwave radiation. Standardization of such methods is not possible because they are not generally applicable. Many polymer compositions tend to decompose during such processing and therefore give inaccurate results.
In these tests, ordinary laboratory equipment as well as flat bottom flasks, air ovens, analytical balances and desiccators are used.
Different test methods published by the American Society for Testing and Materials (ASTM) are also used for the mass fraction of solid components and the volume fraction of solid components:
Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides solid matter content analysis services in paints with its trained and expert staff and advanced technological equipment.
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