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How do you paint plastic?

When spring is coming and with it new blossoms in many colors. Nature loves colors and uses them to achieve different goals such as seduction, attention and deterrence, and so do we. It is clear to everyone that a product that looks boring will not sell, so we put a lot of effort into design and an optimal color combination that will present the right message.

However, plastic raw materials have quite neutral natural colors, for example:

The natural color of polycarbonate, acrylic and polystyrene is transparent. The natural color of polypropylene, polyethylene, acetal and nylon is milky white, and ABS is yellowish.

But although the natural color of the plastic materials is neutral, there are many plastic parts around us that are painted in different colors. The color can be obtained by several methods, below are 2 of them:

1. Painting after production

More suitable for certain materials such as ABS, PC. It can be done by spraying or by electro plating for example.


  • Matte colors and nickel plating are available.

  • A rubber effect can be created.

  • The painting removes damages that result from imperfect injection such as flow marks, and uneven color of the injected part.


  • A relatively expensive process.

  • Extends the delivery date.

  • There are materials that colors do not stick to, and in order to paint them it is necessary to pre-treat the surface, for example applying a binding agent.

2. Coloring the material before it is injected into the mold

This method is divided into two main methods:

A. Dyeing the raw material during its production phase, then inserting it into the injection machine when it is already dyed.

Such coloring is carried out at the manufacturer of the raw material (or at the compounder). In this process, raw material and color are put in individual percentages into a device that mixes materials (called an extruder) where the components are melted and mixed. After mixing, the mixture comes out of the extruder in the form of spaghetti. Later, the spaghetti rods are chopped, turning into flakes of the raw material called compound which is then put into the production process in the injection machine.


  • Finish - excellent mixing of the material and the color, resulting in a very uniform coloring.

  • Execution - the production phase in the injection molding machine is simple.


  • Cost - when the amount of compound produced is small, the production cost is high and this is because the setup costs for the production of the compound are spread over a small amount of material.

  • Time - this is another process that extends the delivery time.

B. The coloring of the material during the injection process

This type of dyeing also has several methods, the principle of all of which is to mix the raw material with individual percentages of color before the material enters the cylinder of the machine. Inside the cylinder the materials are melted, mixed and then injected under pressure into the mold. The accepted methods are:

  • Powders (holcobatch) - in this method, the material is mixed with a very concentrated pigment powder, which coats the plastic grains before they enter the cylinder.

  • Plastic grains with a high concentration of pigments (masterbatch) - in this case it is important that the raw material that forms the basis of the Masterbatch matches the raw material that is being dyed so that the properties of the material that is being dyed are not damaged.

In conclusion Choosing the coloring method depends on the result you want to get, the right pricing for the product, what is accepted in certain areas or markets, as well as many other parameters.Want help finding the best solution for you? Contact us and we will help you.Committed to the success of your next project!Boaz is a foreigner.

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