Matting Agent, Additive to Adjust the Finishing Gloss

Matting agent, flattening paste, or flat paste is an additive material that is used to reduce the gloss of the resulted film produced by a clear coating (top coat). The pure coating will produce a clear and high-gloss film when it is applied to certain surfaces. When the coating is first invented and introduced in the wood finishing, then it is quite difficult to make the finish with low sheen. The low sheen finish was made by adjusting the film thickness or rub of the dry film. But now, you can make a finished film with any gloss by applying the top coat with the desired gloss. With the addition of matting agent, now the top coat can be made and available in any gloss level. Now every finishing person can easily choose the top coat with the proper sheen according to the finishing requirement. 

The first matting agent was made from the silica that was finely grounded and pulverized, but now, with the development of chemical technology, some other materials are being developed to be used as matting agents. Some other materials used for matting agents are: waxes, silica, talc, and aluminum or calcium stearate. The type of material used depends on the desired application and the desired surface finish  If the coating is colored, like enamel or paint, the pigments that are added to the coating will also lower the sheen. The matting agent in the film layer works by refracting the incoming light at the coating film to lower the gloss of the finishing film. For more information, you can go to our previous post : The gloss in the wood finishing.

Now most of the modern top coats are produced and sold with some matting agent inside according to the gloss level of the top coat. And the finishing person can buy the top coat with the specific gloss according to the finish requirement. But if necessary, people still can buy the matting agent alone to adjust the sheen of the top coat gloss level. To set the gloss level of the top coat, you can also mix the top coat with different glosses with the proper ratio. 

 matting agent is refracting the light at the film surface

The addition of matting agents in the top coat is quite easy to do. It does not need advanced equipment and highly skilled people. The finishing person can do it in the finishing shop with a simple process and standard finishing facility. But however, it must be done properly. Here are some things that need to be considered when you need to adjust the sheen by adding matting agent to the clear coating.

• Read the specification of the clear coating and matting agent.

Matting agent is sold in the form of viscous paste, with some resin in the mixture. The pure matting agent is powder, which is very light dust; it is very difficult to be mixed in the thick mixture of top coat. Matting agent that is packaged in a paste form to make it easier to be handled and added to the top coat mixed. But since there is some resin in the mixture, you need to make sure that the matting agent is compatible with the clear coating resin mixture. There are many types of matting agents as well as the type of clear coating. You need to mix the same type of matting agent and the clear coat. You can ask for the technical data sheet of the material or get information from the finishing material supplier to get the proper msterial.

•   Do a right calculation to find the amount of matting agent to be added.

To get the films with proper gloss, you need to add the matting agent in the right amount. Too much matting agent will produce too low sheen, while too little will produce high sheen. Then you need to know the amount of matting agent to be added to the top coat according to the sheen you want. Discuss with the paint supplier to find the proper amount of the matting agent needed. There should be a chart or table showing the correlation between the percentages of matting agent in a mixture and the gloss of the resulting film. Use the information to calculate the amount of matting agent you should add in the top coat.

•  Do good agitation and filtering.

Mating agent essentially is light and fine powder, thpowder; therefore, it is quite difficult to get it in and mix well with the coating which is a viscous mixture. The matting agent is often precipitated and left at the base of the top coat mixture. To produce a perfect mixture, intensive mixing and agitating are needed. When you add the matting agent, then the addition should be done little by little with good agitation. After all of the matting agent has been added and mixed with the top coat, then continue the agitation and make sure the matting is well mixed with the top coat.

Although the well mixing and agitating is already done, there may be some matting agent powder precipitated in the top coat. Then you should filter the top coat mix before applying it. Add some thinner to the mix to reduce the viscosity, and then filter it with the fine filter before applying the top coat.

• Make some tests before doing the application on a large scale.

Top coat is a mixture of resin; you never know the result before it has been applied. Then every time you do some adjustment, you need to test it. Do the mixing in small amounts, record the formula that you use, and apply the coating to a panel or a small item product. See and observe the result; if you get the result in accordance with what you want, then you can use the same formulation and step to the large-scale production.