Masterbatch

A masterbatch is a color resin coloring combination formed of one or more components from a wide number of pigments or dyes and carrier resins, etc., through careful processing and dispersion procedures. It is very effective and concentrated. Masterbatches are in high demand and have a lot of potential for growth. Consequently, masterbatch manufacturing technology has to be researched and developed.

Below, you may find a thorough explanation of masterbatches, including typical categories, fundamental elements, and machinery used in masterbatch manufacture.

1 Masterbatch classification

01. According to different purposes

Masterbatches can be categorized into several grades under the headings of injection masterbatches, blow molding masterbatches, spinning masterbatches, etc.

Toys, electronics cases, cosmetic packing boxes, and other high-end products are made using advanced injection masterbatches; everyday plastic items like industrial containers and everyday household items are made with standard injection masterbatches. When blow molding ultra-thin items, advanced blow molding color masterbatch is employed.

For blow molding and coloring of common package bags and weaving bags, ordinary blow molding color masterbatch is employed. For spinning and painting textile fibers, spinning masterbatch is employed. Fine particles, high concentration, great tinting power, good heat resistance, and good light resistance are all characteristics of the masterbatch pigment. Low-grade items don't need high-quality colors, hence low-grade color masterbatches are utilized to create them.

02.According to the airline,

divided into PE, PP, PVC, PS, ABS, EVA, PC, PET, PEK, epoxy resin, acrylic resin, unsaturated polyester resin, polyurethane, polyamide, fluororesin masterbatch, etc.

03. Depending on various functions

divided into categories such as wood grain masterbatch, imitation marble (flow pattern), antistatic, flame retardant, whitening and brightening, antireflection, anti-aging, antibacterial, etc.

04. Considering how the consumer uses it

both standard color masterbatch and special color masterbatch are recognized. When coloring polymers other than carrier resins, low-melting point PE color masterbatches are frequently utilized as all-purpose color masterbatches. General-purpose color masterbatches are often not produced by the great majority of normal color masterbatch firms worldwide. The technical indications and financial advantages of general-purpose color masterbatches are weak, and their range of application is limited.

Universal color masterbatch exhibits diverse colors in various polymers, and the coloring impact is not very predictable. Particularly for engineering plastics, general-purpose color masterbatch impacts product strength and makes it simple to bend and twist. It is expensive and wasteful to use better heat-resistant grade pigments over general-purpose color masterbatches for general use.

In the course of product manufacturing, the particular color masterbatch has clear benefits such high concentration, good dispersibility, and cleanliness. The plastic used in the product is often compatible with the heat-resistant grade of special color masterbatch. It can be used without risk at normal temperatures, and only when the temperature is too high and the shutdown time is too lengthy will it discolor to varying degrees.

05. In accordance with various hues

divided into masterbatch in colors such as black, white, yellow, green, red, orange, brown, blue, silver, gold, purple, gray, and pink.

2 The fundamental make-up of masterbatch raw materials

01. Colorant

The fundamental element of colour is pigment. To avoid reciprocal flocculation and facilitate dispersion, it is preferable to pre-treat the surface of its tiny particles with resin. Use solvents that have an affinity for pigments and can dissolve resins, such as o-dichlorobenzene, chlorobenzene, xylene, etc., to coat and mix uniformly. In the case of resin dissolution, the pigment is first treated for dispersion before the solvent is either recovered or eliminated.

02.Carrier 

The masterbatch's matrix is the carrier. The carrier for special color masterbatches is now the same resin, which ensures compatibility between the color masterbatch and the resin to be colored and promotes greater pigment dispersion. Polyethylene, random polypropylene, poly-1-butene, and low molecular weight polypropylene are just a few examples of the many different kinds of carrier resins.

LLDPE or LDPE with a high melt index is typically utilized as the carrier resin for polyolefin masterbatches because it has higher processing fluidity. Wetting and dispersing the pigment are accomplished by blending it with the colored resin to change the viscosity of the mixture. Reduce the amount of dispersant used; even without it, a decent dispersion effect may be obtained, protecting the performance of the colored product.

03. A dispersant

The dispersant moistens and coats the pigment, causing it to be evenly distributed in the carrier and to stop coagulating. It has strong compatibility with the resin and a good affinity for the pigment, and its melting point should be lower than the resin's. Low molecular weight polyethylene wax, polyester, stearate, white oil, oxidized low molecular weight polyethylene, and other substances can be employed as dispersants.

04. Supplements

In addition to coloring, masterbatches may also contain antioxidants, antistatic agents, flame retardants, light stabilizers, and other additives depending on the specific needs of the user. When necessary, the masterbatch business will recommend adding additives even if the consumer doesn't specifically ask for them.

3-color masterbatch manufacturing technique

Masterbatch manufacture has stringent guidelines and may be classified into dry process and wet process.

01. Wet method

Phase inversion, granulation, washing, drying, and grinding are the steps used to create the color masterbatch. A number of technical tests are necessary while grinding and processing pigments, including determining the fineness of the grinding slurry, diffusion effectiveness, solid content, etc. The ink method, flushing method, kneading method, and metal soap method are the four wet process techniques.

(1) Using ink

The ink technique is a means of creating ink color paste. Three wheels are used to mill the materials, and the surface of the pigment is covered with a low molecular protective layer. The carrier resin is combined with the ground ink color paste before being plasticized by a two-roller plastic mixer and ultimately being extruded into granules by a single-screw or twin-screw extruder.

(2) The use of a flush

Using a sand mill to reduce the particle size to less than 1 m, the pigment, water, and dispersant are flushed. The pigment is then transferred to the oil phase using the phase transfer technique, evaporated, concentrated, and dried. To create the color masterbatch, extrude and granulate after adding the carrier. Phase inversion necessitates an organic solvent and a matching solvent recovery equipment, both of which are challenging to handle and complex to operate.

(3) Kneading method

The kneading method is to mix the pigment and the oil carrier, and then wash the pigment from the water phase into the oil phase by kneading. The oily carrier coats the surface of the pigment to stabilize the dispersion of the pigment and prevent aggregation. Then extrude and granulate to get the color masterbatch.

(4) Metal soap method

After the pigment has been ground to a particle size of about 1 μm, soap is added at a certain temperature to evenly wet the surface of the pigment particles to form a protective layer of saponified liquid (such as magnesium stearate), which will not cause flocculation and maintain a certain fineness. Then add the carrier and stir and mix at high speed, extrude and granulate to obtain the color masterbatch.

02. The dry method

When creating high-grade masterbatches, some businesses produce pre-dispersed pigments on their own and granulate them using a dry method. Depending on the demands of the product, the color masterbatch manufacturing circumstances provide a number of alternatives. The two most popular manufacturing methods are high agitation with a single screw or high agitation and twin screws. Some businesses powderize the carrier resin to increase the pigments' ability to disperse.

High-quality masterbatch is also produced using internal mixer + single-screw and internal mixer + twin-screw technologies. In order to aid in color matching, more high-performance spectrophotometers are being launched, and masterbatch color measuring and matching technologies are becoming more well-liked.

4 Production tools

Equipment used in masterbatch production includes grinders, mixers, extrusion granulation equipment, high and low speed kneaders, etc. Sand mills, cone mills, colloid mills, high shear dispersers, and other grinding equipment are examples.

The kneader is vacuumed and decompressed to extract volatiles, dehydrate, and exhaust; the thermal working condition is heated by heat conduction oil, steam, or water cooled; the discharge mode is cylinder turning discharge, valve bottom discharge, and screw discharge; and the kneading To change the speed, the paddle uses a frequency conversion governor.

Open type rubber mixing machines and closed type rubber mixing machines are the two categories under which the mixing machine is classified. Equipment used for extrusion granulation comprises single-screw, twin-screw (flat, flat, cone, cone), multi-screw, and non-screw extruders.