No.62: Design of Solvent Composition 

service paint voyager service ct thinner

Key Notes: 

The solvents used in thinners are categorized into three combinations based on their ability to dissolve the resin, which is the main component of paint: true solvent, co-solvent, and diluent. 

Two important points in the design of specialized thinners are: first, that the ratio of diluent to true solvent remains almost constant during the drying process, and second, that the evaporation rate remains relatively equal even when the outdoor temperature changes. 

Design of Solvent Composition 

The solvent composition of thinners is broadly categorized into three types of components: true solvents, co-solvents, and diluents. These categories are based on their ability to dissolve the main component of the paint film, which is the resin. 

    • True Solvent: A solvent that alone has the capacity to dissolve resin and forms the basis of the paint’s dissolving power.
    • Co-solvent: With intermediate dissolving power between a true solvent and a diluent, a co-solvent cannot dissolve polymers on its own but is used to enhance the effect of the true solvent.
    • Diluent: Although it lacks dissolving power, it is crucial for adjusting the viscosity of the paint and improving workability.

In the design of specialized thinners, the composition and balance of ingredients are considered with the aim of adjusting dissolving power and evaporation rate. Notably, the concentration of the true solvent, which significantly affects the adhesiveness of the paint, is given particular attention. 

In the formulation design of thinners, it is also important to consider how much diluent can be mixed with the true solvent. In experiments measuring the maximum dilution ratio (amount of diluent/amount of true solvent), the amount of diluent added to a resin solution dissolved in the true solvent is measured until the solution becomes turbid. This data serves as a guideline for determining the solvent composition of thinners. Moreover, the composition of specialized thinners is devised so that this dilution ratio remains almost constant at any stage of evaporation. This ensures stable paint film performance during the drying process. 

Regarding evaporation rates, there are generally three types: fast-drying, standard, and slow-drying, selected according to the ambient outdoor temperature of the usage environment. For example, the fast-drying type is targeted for low temperatures below 10°C, while the slow-drying type is for high temperatures above 30°C. The standard type is designed for the broadest temperature range, based on 20°C, but in conditions of high humidity above 80%, such as during the rainy season, the use of the slow-drying type is recommended. This is because humidity greatly affects the drying time of the paint. 


    Form đăng ký nhận bản tin email



    Leave a Reply

    Your email address will not be published. Required fields are marked *