Table of Contents
Why Are Modified Plastics More Difficult to Color Than General-Purpose Plastics?
Why Is Color Masterbatch Becoming Increasingly Important in Modified Plastics?
Why Is the Compatibility Between Modified Plastics and Color Masterbatch So Important?
Why Do High-Temperature Engineering Plastics Put More Demands on Color Masterbatch?
A Problem Many People Overlook: Color Is More Than Just “Color”
Real-World Case: Why Is PA66+GF30 More Prone to Color Variation?
In the Future, Modified Plastics Will Pay More and More Attention to “Color”
A lot of people may think in this way when they are first introduced to modified plastics:
"Is it true that modified plastics are nothing but plastics with some other materials added to them?"
But when you get to experience a practical environment, you will soon realize that:
It doesn't matter whether the material is still the same; changing its glass fiber ratio, flame retardant systems, and fillers will make it act totally differently when it comes to its color properties.
For instance:
o The product was expected to be purely black but becomes gray.
o Color inconsistency occurs within the batch itself.
o There are flow marks in injection molding process.
o Yarn breakage rate increases during the spinning process.
o Gel particles or fisheyes form on the films.
So whenever such problems occur, what does anyone always tend to do?
Doesn’t the problem lie in the quality of the color masterbatch?
Actually, there is no straightforward answer to that.
This article will not overwhelm you with too much technical terminology.
Rather, from an application point of view, it will guide you toward a proper understanding of:
l -What kinds of modified plastics really exist out there.
l -Why modified plastics are generally more difficult to color than ordinary plastics.
l -How the formulation of different materials impacts the performance of masterbatch.
l -Which applications need high dispersion masterbatch more than ever before.
l -Why compounders are increasingly paying attention to masterbatch compatibility.
If you have any connection with:
l -Compounding plastics
l -Engineering plastics
l -Injection molding modifications
l -Film applications
l -Fiber spinning
This article will be useful for you.
Modified Plastics are defined as materials whose characteristics are optimized using physical or chemical techniques on base plastic materials.
Put simply,
Unmodified Plastic material is like a "sheet of blank paper".
Whereas, Modified Plastic material is analogous to “engineering drawings that have been filled up with functions”.
Through modification, the material can become:
• Stronger
• More Heat Resistant
• More Impact Resistant
• Flame Retardant
• Lightweight
That is why modified plastics are increasingly being used in:
• Automotive
• Home Appliances
• New Energy
• Packaging
• Artificial Turf
• Pipes and Fittings
• Electronics & Electrical Appliances
But there is an issue associated with all these properties.
It is the complexity of material systems that complicates the coloring process.
This is a problem which often goes unnoticed by most people.
An unmodified plastic consists of a rather straightforward composition.
On the other hand, a modified plastic usually includes the following substances:
• Glass fiber
• Mineral fillers
• Flame retardants
• Toughening additives
• Anti-aging additives
All these materials may affect the behavior of the pigments.
To give an analogy, consider the following:
If you pour ink into pure water, it will be quite easy for the ink to distribute evenly throughout the water.
However, should the water already be filled with sand, foam and other particles, then of course the ink will find it very difficult to disperse homogeneously.
That is why:
There is a growing number of organizations who began to use such terms as:
• Best color masterbatch for modified plastic
• High dispersion masterbatch
• Custom masterbatch for engineering plastics
This is because conventional color masterbatch can no longer satisfy their needs.
One of the most popular kinds of engineering plastics.
Examples of this group are:
• PA6+GF
• PA66+GF30
• PP+GF
• PBT+GF
Adding glass fiber makes the compound:
• More durable
• More dimensionally stable
• Heat resistant
Therefore, these materials have become very common for use in:
• Structural automotive parts
• Blades for fans
• Appliance housing
• Other industrial uses
However, glass fiber is responsible for one particular feature.
Adding glass fiber changes how light reflects inside the compound.
Thus, the identical black masterbatch may appear absolutely differently in the compounded material with a higher/lower amount of glass fibers.
According to our experience,
PA66+GF30 is among the compounds most sensitive to color variations.
Flame retardant materials are widely used in electronics, appliances, and new energy vehicles.
The basic idea is very clear:
Prevent burning!
However, in case of color masterbatch, flame retardant systems are more likely a "difficult level".
The simple explanation is that there are quite a few flame retardants which can influence pigments' stability.
This problem is especially common for:
• Yellow colors
• Red colors
• Purple colors
Under high temperatures, these colors will be dulled and darkened.
In the flame retardant system, the color masterbatch usually suffers from the following problems:
• Color migration
• Graying effect
• Loss of gloss
For this reason, in a flame retardant system, heat resistant masterbatch and flame retardant compatible masterbatch should be used.
The following fillers are often added to grades of PP and PE modification:
• Talc
• Calcium carbonate
• Barium sulfate
This is primarily done for:
To save money.
However, as the content of fillers increases, other issues occur:
Vividness of the color is significantly lost.
This applies to hues such as:
• Gray
• Blue
• Green
These colors tend to look dirty and washed out easily.
That is the reason why fillers are usually reliant on:
• High tinting strength masterbatch
• High loading masterbatch
Most plastics are rigid in nature, but can also be quite brittle.
In order to overcome this problem, toughening agents are added by manufacturers.
Examples where this process is used include:
• ABS
• PP
• Nylon
The real problem here lies not in the color per se, but in the "visual appearance consistency."
This becomes especially important when dealing with high gloss materials.
If the dispersion of the masterbatch is not sufficient, then chances are that you will experience issues like:
• Flow lines
• Silver streaking
• Poor gloss levels
These problems are very commonly experienced in home appliance housing.
In the past, pigments in powder form were commonly incorporated into factories' processes.
Today, more and more businesses are turning towards:
• color masterbatch for engineering plastics
• masterbatch for modified plastics
This change can be attributed to three major reasons.
In color masterbatch, pigments are already dispersed in advance inside a carrier polymer.
Hence, there is more even dispersing of colors than with use of dry powder.
This is particularly important in cases where high speed production is involved such as:
• Fiber spinning
• Non-woven
• Blow film
Many modified materials demand very tight color consistency.
Typical examples include:
• Automotive interior parts
• Home appliance housings
• Pipe systems
When using masterbatch, it becomes much easier to control ΔE variation from batch to batch.
One of the biggest drawbacks of pigment powders:
They create dust very easily.
This is especially true for carbon black.
Using color masterbatch can significantly improve the working environment on the shop floor.
Often the consideration of carrier compatibility is overlooked.
However, this is indeed very important.
Example:
Modified Polymer – Suggested Carrier Polymer for Masterbatch
Modified PA – Carrier PA
Modified PP – Carrier PP
Modified ABS – Carrier ABS
When the carrier system fails to be compatible:
Some of the issues that you may face include:
lDelamination
lSurface migration
lInconsistent distribution
In some cases, it could lead to poor mechanical properties of the end product.
Processing temperatures for various types of plastics vary greatly.
For instance:
Type of Material—Processing Temperature
PE—180-220°C
PP—200-240°C
PA66—260-300°C
The higher the temperature of processing, the tougher the requirements for pigment heat stability.
In case of inadequate heat stability:
The pigment will:
• Become yellow
• Lose brightness and darkness
• Drift off the desired tone
Thus:
Engineering plastics always need:
• Heat resistant masterbatch
• Engineering plastic masterbatch
Most buyers usually care only about one thing:
"Is there any match between the color and the standard sample?"
However, in the manufacturing process,
The deciding factor that governs stability is:
ldispersion
lcompatibility
lthermal stability
lbatch stability
This is particularly important in the field of modified plastics.
In this case, a color masterbatch actually works as a "stabilizer."
It can never be considered simply as "color."
This is one challenge faced by many plastics engineering companies.
From our tests we have found that:
Glass fiber alters the light reflection in the material.
Hence, we find that:
One black masterbatch will appear to be entirely different in color when used with various glass fiber loads.
As a result, more and more companies started using:
PA carrier masterbatch
High jetness black masterbatch
Historically, the colored plastics industry was primarily concerned with:
- Strength
- Fire resistance
- Cost
However, today:
An increasing number of finished products are increasingly concentrating on:
- Visual uniformity
- High-quality finish
- Long-lasting visual stability
This is most pronounced in applications such as:
- New energy vehicles
- Premium home appliances
- Consumer electronics
- Artificial grass
The importance of color masterbatch in the colored plastics industry is only going to increase even further in the future.
1. Are color masterbatches necessary for all types of modified plastics?
Yes, especially if the system is complex; otherwise, an ordinary masterbatch can fail to cope with it.
2. Why are materials reinforced by glass fibers prone to color fluctuations?
Due to the effects of glass fiber on both light reflection from the material and pigment dispersion within it.
3. Why do flame retardants result in darkening the material?
The fact is that many flame retardants adversely affect pigment thermal stability.
4. Why do materials rich in fillers have a grayish color?
This is because fillers reduce color intensity and hiding power of the pigments.
5. Why are modified ABS materials prone to flow marks?
Usually, such problems are associated with pigment dispersion and the compatibility of the system.
6. Why does heat resistance play a vital role for engineering plastics?
High processing temperatures require more pigment thermal stability from the material.
7. Will color masterbatch influence the mechanical properties of the material?
Properly developed formulations should not affect them too much.
8. Why are high-dispersion masterbatches costlier than others?
This is due to the increased complexity of formulation and dispersion procedure.
9. What can we say about the future trends in modified plastics?
Along with mechanical characteristics, color uniformity will play a key role.
