Environmental performance is becoming increasingly important in coating factories.

Reducing VOCs.
Reducing waste paint and waste thinner.
Improving the working environment.
Controlling odors.
Reducing waste treatment costs.
Meeting customer audit requirements.
Complying with environmental regulations.

Powder coating, waterborne paints, low-VOC paints, and high-solids paints are strong options for addressing these challenges.

Powder coating uses almost no solvents, and oversprayed powder can sometimes be recovered.
Waterborne paints offer an option for reducing solvent consumption.
Low-VOC and high-solids paints may reduce VOC emissions.

However, there is a point that requires attention.

Environmentally oriented paints should not be selected solely because they are good for the environment.
Coating is a process that cannot be established by materials alone.

Workpiece material.
Pretreatment conditions.
Coating method.
Film thickness.
Appearance requirements.
Drying and baking conditions.
Equipment specifications.
Working environment.
Wastewater and waste treatment.
Quality assurance criteria.

Environmentally oriented coating can be applied in practice only after these factors have been checked together.

1. Environmentally Oriented Coating Involves More Than a Material Change

When improving environmental performance in the coating process, people sometimes consider changing materials first.

Switching from solvent-based to waterborne paint.
Switching from solvent-based to powder paint.
Switching from conventional to low-VOC paint.
Switching from a high-solvent to a high-solids formulation.

These are important options.

However, changing materials alone may cause quality defects or reduced productivity if the overall coating process is not compatible.

For example, a change to waterborne paint causes insufficient drying if drying conditions are unsuitable.
Powder coating cannot be applied if the workpiece cannot withstand the baking temperature.
Low-VOC paint may differ from the conventional product in workability or appearance.
High-solids paint may make viscosity and film thickness control more difficult.

Environmentally oriented coating needs to be considered as a process change, rather than simply a material change.

2. Powder Coating Is an Effective Option for Reducing VOCs

Powder coating deposits powdered paint on a workpiece using electrostatic attraction or other methods, then heats it to form a coating film.

In general, powder coating uses almost no solvents.
It can therefore be advantageous for reducing VOCs.

Equipment that recovers and reuses oversprayed powder paint can also reduce paint waste.

The main advantages of powder coating are as follows.

• Substantial VOC reduction is readily achievable
• Little waste thinner is generated
• Recovered powder may be reusable
• Thick films are easy to form
• Corrosion protection and durability may be readily achieved
• The working environment may improve

However, powder coating is not a universal solution.

The following checks are needed before application.

• Can the workpiece withstand the baking temperature?
• Can the required appearance be achieved?
• Does it match film thickness requirements?
• Can the required color change frequency be accommodated?
• Is powder recovery equipment available?
• Are pretreatment conditions appropriate?
• Can dust explosion risks and safety management be addressed?
• Is the powder paint storage environment suitable?
• How will recoating and repair be performed?

Powder coating is an effective environmental option, but must be assessed together with product, equipment, and operating conditions.

3. Waterborne Paints Reduce VOCs, but Drying Management Is Difficult

Waterborne paints replace some or most of the solvent with water.

They attract attention as an environmental option because they may reduce VOCs compared with solvent-based paints.

However, waterborne paints have their own difficulties.

Drying management is particularly important.

Water has different evaporation characteristics from organic solvents.
Drying behavior may change substantially with temperature, humidity, air volume, film thickness, and workpiece temperature.

Insufficient drying may cause the following problems.

• Insufficient drying
• Sagging
• Popping
• Blisters
• Poor adhesion
• Gloss defects
• Insufficient coating film performance
• Marks left during subsequent processes

Wastewater and sludge management also become important with waterborne paints.

Conversion to waterborne paints does not eliminate waste.
Booth water, paint residue, sludge, wastewater treatment, and control of decomposition and odors may require management.

When considering waterborne paint, assess drying conditions, humidity control, wastewater treatment, and quality verification together with VOC reduction.

4. Low-VOC Paints May Improve Environmental Performance While Staying Close to the Existing Process

Low-VOC paints are intended to reduce VOC emissions compared with conventional solvent-based paints.

Compared with conversion to waterborne or powder coating, they may allow improvement while retaining existing equipment.
They can therefore be a strong option for factories seeking environmental improvement without major changes in equipment investment.

However, low-VOC paints also require certain checks.

• Is application viscosity appropriate?
• Does the dilution ratio change?
• Does drying time change?
• Is coating film performance equivalent to the conventional product?
• Is appearance satisfactory?
• Is film thickness easy to control?
• Is the paint compatible with spray guns and pumps?
• Does the cleaning method change?
• How do costs change?

Low-VOC paints may look like a simple substitution.
However, failure to check coating conditions, drying conditions, and inspection criteria can lead to shop-floor problems.

5. High-Solids Paints Increase the Proportion of Solids in Paint

High-solids paints increase the proportion of solids in the paint and reduce the relative amount of solvent.

Solids are the components that remain as a coating film after drying.
A higher solids content may reduce the amount of solvent needed to produce the same film thickness.

The advantages of high-solids paints are as follows.

• They may reduce VOCs
• They may reduce paint waste
• They may be suitable for forming thick films
• Existing solvent-based coating equipment may remain usable

There are also points requiring attention.

Paints with a high solids content may tend to have higher viscosity.
Sprayability, leveling, film thickness control, and dilution management therefore become important.

If the paint builds up readily, care is also needed to avoid excessive film thickness and sagging.
Drying conditions and coating film performance must also be checked.

High-solids paints are an effective option for reducing VOCs, but workability and film thickness control need to be checked together.

6. Select Environmentally Oriented Paints by Working Back from Quality Requirements

The first important step in selecting environmentally oriented paint is to confirm quality requirements.

What appearance is required?
What film thickness is required?
What corrosion protection is required?
What chemical resistance is required?
What weather resistance is required?
What abrasion resistance is required?
At what temperatures will the product be used?
Is it for indoor or outdoor use?
Are there customer specifications?
Will repair be necessary?

Changing paint solely for environmental reasons without checking these points may fail to meet quality requirements.

Environmentally oriented paints are not intended to sacrifice quality.
They are options for reducing environmental impacts while meeting the required quality.

The following sequence is therefore important in paint selection.

First, confirm the required quality.
Next, check the workpiece and service environment.
Then consider environmentally oriented paints that match the equipment, drying conditions, and work methods.

Environmental improvement should proceed by working back from quality requirements.

7. Workpiece Material Determines Which Environmentally Oriented Coating Methods Can Be Applied

Workpiece material is extremely important when considering environmentally oriented coating.

Metal.
Aluminum.
Stainless steel.
Magnesium.
Plastic.
Wood.
Glass.
Paper.
Composite materials.

Applicable coating methods and drying conditions change with the material.

For example, powder coating requires a baking temperature.
It may be readily applicable to metal, but difficult for heat-sensitive plastics.

With waterborne paints, workpiece surface wettability, pretreatment, and drying conditions are important.
For plastics, issues beyond adhesion and solvent cracking also need to be checked.

Even low-VOC paints require verification of substrate adhesion, drying behavior, and coating film performance.

Environmentally oriented coating cannot therefore be selected by paint name alone.
Compatibility with the workpiece material must always be checked.

8. Check Compatibility with Pretreatment

Coating quality is not determined by paint alone.
Compatibility with pretreatment is extremely important.

Whether using powder coating, waterborne paint, or low-VOC paint, the surface must be in a suitable condition for the coating film to adhere firmly.

Items to check are as follows.

• Has oil been removed?
• Are rust and oxide films controlled?
• Is conversion treatment appropriate?
• Is rinsing sufficient?
• Is drying sufficient?
• Is the surface free from residual dust or salts?
• Is the storage time after pretreatment excessive?
• Has recontamination occurred after pretreatment?

After changing to an environmentally oriented paint, existing pretreatment conditions may not provide stable adhesion or appearance.

When considering a paint change, check pretreatment conditions together with it.

9. Check Equipment Compatibility

Equipment compatibility must be checked when introducing environmentally oriented coating.

Powder coating requires a powder coating booth, powder gun, recovery system, baking oven, and suitable pretreatment equipment.
Waterborne paints may require drying equipment, humidity control, and paint supply equipment designed with stainless steel or corrosion resistance in mind.
For low-VOC and high-solids paints, check the suitability of spray guns, pumps, hoses, nozzles, and cleaning methods.

The following equipment should be checked.

• Coating booths
• Coating guns
• Pumps
• Hoses
• Paint supply equipment
• Drying oven
• Baking ovens
• Exhaust equipment
• Supply air equipment
• Wastewater treatment equipment
• Powder recovery equipment
• Cleaning equipment
• Explosion protection and safety equipment

Changing paint alone cannot produce stable production if the equipment is incompatible.

Environmentally oriented coating needs to be assessed in terms of both materials and equipment.

10. Waste May Increase in Another Form

Introducing environmentally oriented coating may reduce one type of environmental impact while adding other management requirements.

For example, waterborne paints effectively reduce VOCs, but wastewater and sludge management become important.
Powder coating effectively reduces waste thinner, but recovered powder management, dust control, and powder loss during color changes may become challenges.
Low-VOC paints may reduce VOCs, but changes in cleaning methods and workability require attention.

Environmentally oriented paints therefore do not solve every problem at once.

What matters is defining beforehand what will decrease and what will newly require management.

Will VOCs decrease?
Will waste thinner decrease?
Will waste paint decrease?
Will sludge increase?
Will the wastewater treatment load increase?
Can powder recovery losses be controlled?
What will happen to waste during color changes?
Will cleaning time increase?

Environmental performance must be evaluated through the overall INPUT / OUTPUT.

11. Operator Training Is Also Necessary

Operator training is also important when converting to environmentally oriented coating.

Changing paint may change the feel of the work.

Waterborne paints may differ from conventional solvent-based paints in drying behavior and perceived viscosity.
Powder coating requires attention to judging film thickness, gun operation, grounding management, and recovered powder management.
High-solids paints require attention to output, film thickness, and sagging.
Low-VOC paints may change dilution and cleaning methods.

Switching without operators understanding these differences makes quality defects more likely.

The following items should be covered in training.

• Characteristics of the new paint
• Dilution method
• Application conditions
• Film thickness control
• Drying conditions
• Cleaning and washing methods
• Waste separation
• Safety precautions
• Criteria for reporting abnormalities
• Differences from the conventional product

Environmentally oriented coating requires people’s understanding, as well as materials and equipment.

12. Steps for Considering Environmentally Oriented Coating

The following steps make consideration of environmentally oriented coating easier to organize.

Step 1: Clarify the purpose

Do you want to reduce VOCs?
Do you want to reduce waste thinner?
Do you want to reduce waste paint?
Do you want to improve the working environment?
Do you want to meet customer audit requirements?
Do you want to reduce treatment costs?

The appropriate method changes with the purpose.

Step 2: Examine the current INPUT / OUTPUT

Check paint consumption, thinner consumption, waste paint, waste thinner, VOCs, wastewater, sludge, and treatment costs.

Step 3: Confirm quality requirements

Check appearance, corrosion protection, durability, film thickness, adhesion, service environment, and customer specifications.

Step 4: Check the workpiece and pretreatment

Check material, shape, pretreatment conditions, recontamination risks, and drying conditions.

Step 5: Check equipment compatibility

Check coating booths, guns, curing ovens, exhaust, wastewater treatment, and powder recovery equipment.

Step 6: Perform trial production and evaluation

Check adhesion, appearance, film thickness, drying behavior, durability, and workability.

Step 7: Establish operating rules

Standardize mixing, coating, drying, cleaning, waste separation, training, and responses to abnormalities.

Following this sequence makes environmentally oriented coating easier to establish in day-to-day operations.

13. CoatureVietnam’s Approach to Proposing Environmentally Oriented Coating

CoatureVietnam does not propose powder coating, waterborne paints, or low-VOC paints merely as environmental products.

What matters is whether they match the customer’s objectives and shop-floor conditions.

Do you want to reduce VOCs?
Do you want to reduce waste thinner?
Do you want to improve the working environment?
Do you want to reduce paint waste?
Do you want to meet customer audit requirements?
Do you want to reduce long-term costs?

After confirming the purpose, compatibility is assessed from the perspectives of Material, Method, Machine, Man, and Management.

Material: Selection of paint, thinner, and pretreatment agents.
Method: Coating methods, film thickness, drying, cleaning, and standard work.
Machine: Booths, curing ovens, exhaust, powder recovery, and wastewater treatment.
Man: Operator training, decision criteria, and abnormality reporting.
Management: Investment decisions, costs, environmental regulations, and customer audits.

Environmental improvement is more than a material substitution.
It is a redesign of the entire coating process.

Summary

Powder coating, waterborne paints, low-VOC paints, and high-solids paints are strong options for environmental improvement.

Powder coating may be effective for VOC reduction and paint recovery.
Waterborne paints provide an option for reducing solvent consumption.
Low-VOC paints may reduce environmental impacts while staying close to the existing process.
High-solids paints increase the components that remain as a coating film and reduce the amount of solvent.

However, none of these methods is a universal solution.

Workpiece material.
Pretreatment.
Drying conditions.
Equipment compatibility.
Film thickness.
Appearance.
Durability.
Wastewater and sludge.
Powder recovery.
Cleaning methods.
Operator training.

Switching without checking these factors may turn an intended environmental improvement into quality defects or operator burden.

Environmentally oriented coating is not intended to sacrifice quality.
It is an option for reducing VOCs, waste, operator burden, and cost losses while preserving the required quality.

CoatureVietnam considers environmentally oriented coating by connecting materials, equipment, work methods, people, and management.
It proposes improvements that become established in practice, matching customer objectives and shop-floor conditions.

Coating the Future with Science and Care.
Environmentally oriented coating is an important option for moving toward coating processes that are friendly to the people working on the shop floor and to factory management, as well as to the environment.