We all know that you should always try and run a color concentrate with a carrier resin that matches the material that you running it in. But what if you don’t have the right color concentrate?
If you don’t know, color concentrate is made up of pigments and additives that are encapsulated in a polymer carrier resin. Color concentrates are typically supplied in a pellet form. The polymer basically encapsulates the powdered pigments and additives. This makes color easy to handle and safer too. Powders can become airborne and when they do, they are an explosion hazard not to mention unhealthy for people to breath. Color concentrates are typically about half additives and pigments and about half carrier resin.
Whenever possible we like the carrier resin to be the same material that you are blending the color concentrate into. It doesn’t need to be the same grade, just the same material. Use ABS carrier in ABS or nylon carrier in nylon etc.
But, there are those times when you just can’t do this. You need something in a pinch and you don’t have the correct color concentrate available. Maybe you need to run some sample parts out of black ABS but you only have natural in stock.
What I want to do hear is to provide a list of color concentrates that you could use in a pinch. The first choice is always going to be a carrier resin that matches the material that you are molding. Accepting that your first choice is unavailable, I want to show what the second choice, third choice and fourth choices might be.
Here is the list, with notes below.
Material you are molding 2nd Choice 3rd Choice 4th Choice
ABS SAN PE –
ABS/PC Alloy ABS PE¹
ASA ABS PE
ASA/PC Alloy ASA ABS PE¹
Acetal² PE EVA
Acrylic PE EVA
Nylon 6 ABS PE EVA
Nylon 6/6 Nylon 6 ABS PE¹
Nylon 4/6, 6/10, 6/12, 6,6/6 Nylon 6
Polycarbonate ABS PBT PET
PC/PBT Alloy PBT PE¹
Polyester (PBT) EVA¹ PE¹
Polyester (PET) PBT PC
Polyethylene³ EVA PP
PPO/PS (Noryl) PS ABS
PPO/PA (Noryl GTX) Nylon 6 ABS
Polypropylene PE EVA
Polystyrene ABS PE
PVC PE EVA
TPO PP PE EVA
TPV PP PE EVA
SAN ABS PE
SBC PE PP EVA
Note 1: This color concentrate might melt or get sticky at the typical drying temperatures for this material. Material must be dried before adding color concentrate and great care must be taken to prevent bridging in the feed throat.
Note 2: Acetal homopolymer carriers can be used in copolymers and vice-versa.
Note 3: HDPE, LDPE and MDPE are all compatible.
Keep in mind that you might have to take some special precautions when using some of the above non-ideal color concentrate combinations. Using a PE, or EVA color concentrate in a higher heat material like Nylon 6/6 or PET might be troublesome. The carrier resin might get soft in the dryer or in the feed throat of the molding machine. You might have to dry the material separately and blend in the color concentrate in a bucket and put small amounts in the machine. You would not do this for production, but in a pinch, you could do it for a small run.
On the other hand, some of these combinations will run surprisingly well, such as ABS color concentrate in Nylon. The problem is that you might be suffering some property loss without knowing it so this is still not a good long term strategy.
Also keep in mind that if the color concentrate has a carrier resin that is hygroscopic (absorbs moisture), such as ABS or nylon, it will need to be dried just like the material.
I hope this helps to clear up some of the confusion.