1-What is master batch?
Master batch is a solid or liquid additive for plastic used for coloring plastics (color master batch) or imparting other properties to plastics (additive master batch).
Master batch is a concentrated mixture of pigments and/or additives encapsulated during a heat process into a carrier resin (polymer)
2-What is the benefits of master batch usage?
- Low stock holding compared with pre-compounded materials
- Optimum dispersion of pigments/additives
- Dust free, no health and safety risks in comparison to undispersed fine powder pigments or additives
- Elimination of 'trial and error' development or formulation work, as this done by the master batch supplier who takes responsibility for color and consistency
- Reduction in purging/cleaning costs
3-How master batch been made?
In simple terms, manufacture is a two-stage process: gathering ingredients and then mixing them together by applying heat and shear to produce a homogenized pellet. Generally, high or low speed mixers are been used to produce a pre-mix of the additives that is then compounded on roller mills, kneaders, single or twin-screw extruders. Even distribution (dispersion) and development (breaking down) of the additives throughout the carrier are essential. This processing depends on several key elements: formulation, quality of raw materials, and quality of mixing and compounding machine. Finally, the finished master batch is pelletized (die-face or strand cut).
4-How can I use Master batch?
Using Master batch can been introduced to the processors' base polymer on the production line in a number of ways, the most successful methods being volumetric or gravimetric dosing. In both techniques, the master batch is been added directly into the polymer stream immediately before processing. Volumetric dosing has the advantage of relatively low capital investment but requires calibrating every time the batch or color is been changed (depending on the bulk density of the material). Gravimetric dosing is extremely accurate, but plant is expensive.
5-What is the important parameters for master batches?
- Color tone
- Color opacity
- Dispersion of MB
- MFI & Bulk density of MB
- Polymer carrier and its MFR
- Weather ability and UV protection
- Surface smoothness
- Color performance
- Pigment compliance
- Final application
6- How can I test the master batch?
- Two roll mills
- Press molding
- Film plants
- Injection molding
- Melt flow index
- Ash content
- Filter press value
- Pilot spinning plant
- Color cabinet
- Bulk density
7-What the application of master batch?
- Blow molding
- Injection molding
- Sheet extrusion
- Pipe extrusion
- Cast films
- Woven sacks
- Synthetic fiber
8-How can I Identify the color degradation in extrusion, injection molding, blow molding and film blowing applications?
- Inconsistency of color in manufactured articles.
- Discoloration of Manufactured article compared to STD.
- Darkening of Manufactured article.
- Yellowing/Browning of Manufactured article.
- Black spots or streaks in manufactured article.
9- What are the various causes of processing temperature fluctuations?
Manual error where the operator enters the incorrect temperature settings. Maintenance on machinery - heater band or cartridge heater malfunction, thermocouples malfunction; insufficient water cooling, compression ratio to high. Cycle time - extended dwell time at higher end temperatures. Electrical relay problems.
10-What is the effect of temperature on the Master batch?
There are two types of pigments used in the plastics manufacturing industry - organic and inorganic. There high quality organic & inorganic pigments are stable in the manufacturing process up to temperatures of 240'C to 300'C.
Certain organic pigments & inorganic pigments are heat sensitive and are only stable from 140'C to 200'C before they start degrading.
Processing temperatures at the lower end of the spectrum will ensure color consistency.
Processing temperatures exceeding the recommended stabilities will cause the discoloration of the manufactured article also referred to as fading or yellowing of the final part, as specified by Performance Color Systems will result in color degradation.
Thus, the manufactured article will not conform to the standard article and in extreme cases, you will get product failures.