We encounter plastics every day since they are lightweight, easy to use and versatile. However, over time its color does fade and age, meaning we may have to consider painting the plastic, be it for home decoration or improving the product’s aesthetics.
With all that being said, can we even paint on plastic surfaces? If so, how can we optimize the durability and effectiveness of the paintwork?
Why Paint Plastic?
There are some practical advantages to painting plastic. Firstly, painting can give an old chair, toy, or other items a fresh new bright look.
Secondly, this extra coating would give more protection for plastic from UV rays and enhance durability from daily wear and tear which prolonging its life and minimizes risks of aging or weathering and cracking.
What is more, refinishing an older item means saving a budget while equally salvaging waste, which is an economical and eco-friendly practice in itself.
Can All Different Plastics Be Painted?
Not all plastics are painted, and it all depends on their properties.
Like polyvinyl chloride (PVC) and ABS, the plastics’ surfaces are relatively easy to work with because ordinary primer and spray paint can be adhered firmly.
But like polypropylene (PP) and polyethylene (PE), this kind of slippery molecule have very smooth surfaces, ordinary paints have difficulty attracting to them, and one needs a special plastic primer in order to paint them successfully.
Moreover, new plastic surfaces may have residue from the mold release, like an invisible oil film; if direct paint is applied, it may not stick well and is likely to peel off within a few days. In this case, cleaning or letting dry before painting is needed.
In general, most plastics can be painted; however, some are easy to paint, while others need some treatment prior to guarantee a solid coating.
For plastics that can’t be easily painted, we can apply surface treatment:
- Sanding
Sand the plastic surface with sandpaper or grinding wheel to remove the smooth layer and dirt, increase the roughness and improve the paint adhesion. - Chemical Cleaning
Remove grease, dirt and other impurities from plastic surfaces by using chemical solvents such as isopropyl alcohol, acetone, etc. or cleaning agents. - Use Specialized Surface Treatment
Use specialized surface treatment agent to improve the surface energy of plastic and help the paint to adhere better, especially for difficult-to-paint plastics such as PP and PE. - Use of primers
The primer helps to fill small pores in the plastic surface, resulting in a more uniform and stronger coating.
Common Plastic Painting Applications
1. Automotive industry: internal and external plastic parts of automobiles, such as instrument panels, door handles, bumpers, etc.
2. Consumer electronics: plastic shells such as cell phone cases, home appliance shells, etc.
3. Home decoration: plastic furniture, lamps, wall decorations, etc.
4. industrial equipment: plastic parts such as plastic gears, valves and housings in mechanical equipment,.
These applications demonstrate the important role that plastic painting plays in a number of industries, not only enhancing appearance but also providing additional protective features.
Step-by-Step Guide on How to Paint Plastic
Painting plastics in a large plastics processing plant actually follows these five steps:
Clean the surface
First use ultrasonic cleaning machine to wash off the plastic surface of the dirt and oil stains, and then add some industrial degreasing agent, wash and blow dry with hot air.
Sanding the surface
Next, get on the automated belt sander or sandblasting equipment and sand the plastic surface like electric sandpaper to make the surface rough and remove the shine. After sanding use a high pressure air gun to blow away the dust and wait for the next step.
Preparing for painting
Plasma or flame treatment equipment is used to “activate” the plastic surface so that the paint will adhere more firmly. A robotic arm is then positioned on the assembly line to block off areas that do not want to be painted. The temperature is controlled at 10-32°C and the humidity is stabilized.
Applying primer
The primer is sprayed with an automatic sprayer, with the nozzle following a set route, 30 cm away from the plastic, spraying 2-3 thin layers, and each layer is thrown into an infrared curing oven to bake for 5-10 minutes to make it dry.
Applying paint
Finally, use the mechanical arm to spray the top coat, 30-45 cm away from the surface, evenly spray 2-3 layers, each layer into the UV curing oven to bake for 1-2 minutes.
Drying times
Your painted plastic surface needs proper curing time to develop maximum durability.
| Stage | Time | Description |
| Touch Dry | 20 minutes | Surface dry, can handle lightly. |
| Handle with Care | 30 minutes | Can touch, avoid friction. |
| Fully Dry | 24-48 hours | Completely dry, ready for use. |
| Fully Cured | 3-5 days | Fully cured, suitable for heavy use. |
If you paint plastics at home, in fact, the process is similar to the factory, both need surface treatment, the difference is not great.
Only the factory is a high-flying machine, such as ultrasonic cleaning, automatic spraying, at home with ordinary sandpaper and soapy water, hand rubbing and grinding can also work.
Five Keys to Painting Success
- Control time and temperature: After each coat, make sure it is completely dry, preferably at a temperature of10-32°C so that the paint will adhere better.
- Painting tips: apply paint in thin coats, keep the spray can 30-46cm away from the surface, and avoid applying too thick so that the result will be more even.
- Avoiding common mistakes: don’t skip the cleaning or sanding steps, and don’t apply paint when humidity is high or temperatures are extreme, applying paint too thickly can also lead to dripping.
- Storage and handling: Keep painted items in a clean place, avoid stacking or touching other things, and make sure they don’t stick together.
- Painting protection: For commonly used items, you can apply a clear acrylic sealer for protection and do not use strong chemical cleaners, which will keep the coating for a longer period of time.
Conclusion
With the tips in this guide, you can give old plastic items a new look. If you need high-quality plastic products or custom painting services, our company offers a variety of solutions to help you realize your ideas and ensure that your products are beautiful, long-lasting, and up to par.
FAQs
Can you paint plastic items successfully?
Yes, painting plastic is possible and can yield successful, long-lasting results with proper preparation and techniques.
What are the challenges of painting plastic surfaces?
Plastic surfaces present challenges such as their smooth texture, temperature sensitivity, and the tendency for paint to crack or flake if not properly prepared.
What tips can help ensure successful results when painting plastic?
A few tips may ensure satisfactory results: Allow sufficient time to dry before handling plastic items, handle painted items carefully not to damage them, and give paint a proper amount of time to harden before subjecting the item to the rigors of normal use.
Do you need to use special paint for plastics?
Yes, it is best to use a special paint for plastics. Traditional paints have very poor adhesion and fail to produce a resistant protective finish. Plastic paints grip better and are thus more durable and long-lasting.