Views: 13 Author: Site Editor Publish Time: 2023-10-02 Origin: Site
Color masterbatch is a high-efficiency and high-concentration color resin coloring mixture made from one or more components of a large number of pigments or dyes and carrier resins through strict processing and dispersion processes. Color masterbatch is in great demand and has huge development potential. Therefore, the research and development of color masterbatch production technology is very necessary.
Below we have a comprehensive understanding of color masterbatch, including common classifications, basic ingredients, color masterbatch production processes and equipment, and finally take a look at the application and future development of color masterbatch.
1. Classification of color masterbatch
01. Depending on the purpose
Color masterbatch is divided into injection masterbatch, blow molding masterbatch, spinning masterbatch, etc. Each variety can be divided into different grades.
High-grade injection masterbatch is used for cosmetic packaging boxes, toys, electrical appliance casings and other high-end products; ordinary injection masterbatch is used for general daily plastic products, industrial containers, etc. Advanced blow molding masterbatch is used for blow molding coloring of ultra-thin products.
Ordinary blow molding masterbatch is used for blow molding coloring of general packaging bags and woven bags. Spinning masterbatch is used for spinning and coloring textile fibers. The masterbatch pigment has fine particles, high concentration, strong tinting power, and good heat resistance and light resistance. Low-grade color masterbatch is used to manufacture low-grade products that do not require high color quality.
02. Depending on the carrier
Divided into PE, PP, PVC, PS, ABS, EVA, PC, PET, PEK, phenolic resin, epoxy resin, acrylic resin, unsaturated polyester resin, polyurethane, polyamide, fluororesin masterbatch, etc.
03. Depending on different functions
Divided into antistatic, flame retardant, anti-aging, antibacterial, whitening and brightening, anti-reflective, weather-resistant, matting, pearlescent, imitation marble (flow pattern), wood grain masterbatch, etc.
04. Depending on the user’s usage
It is divided into general color masterbatch and special color masterbatch. Low melting point PE masterbatch is often used as a general masterbatch, suitable for coloring other resins besides carrier resin.
Universal masterbatch shows different colors in different plastics, and the coloring effect is less predictable. General masterbatch affects product strength, and the product is prone to deformation and distortion, especially for engineering plastics. In order to be universal, general color masterbatch uses higher heat-resistant grade pigments, which costs more and causes waste.
Special color masterbatch has significant advantages such as high concentration, good dispersion and cleanliness during product processing. The heat-resistant grade of the special color masterbatch is generally compatible with the plastic used for the product. It can be used with confidence at normal temperatures. It will only cause varying degrees of discoloration when the temperature exceeds the normal range and the downtime is too long.
05. Depending on different colors
Divided into black, white, yellow, green, red, orange, brown, blue, silver, gold, purple, gray, pink masterbatch, etc.
2. Basic components of masterbatch raw materials
01. Pigment
Pigment is the basic coloring component. It is best to pre-treat it first and coat the surface of its fine particles with resin to prevent mutual flocculation and make it easy to disperse. In order to coat and mix evenly, use solvents that have affinity for pigments and can dissolve resin, such as o-dichlorobenzene, chlorobenzene, xylene, etc. In the case where the resin is dissolved, the pigment is dispersed and then the solvent is recovered or removed.
02. Carrier
The carrier is the matrix of the masterbatch. At present, special masterbatch uses the same resin as the carrier, which can ensure the compatibility between the masterbatch and the colored resin and facilitate better dispersion of pigments. There are many types of carrier resins, including polyethylene, random polypropylene, poly-1-butene, low molecular weight polypropylene, etc.
For polyolefin masterbatch, LLDPE or LDPE with high melt index is generally used as the carrier resin. It has good processing fluidity. It can be blended with the colored resin to adjust the viscosity of the system, which can infiltrate and disperse pigments, minimize the amount of dispersant, and achieve good dispersion effects even without a dispersant, and ensure that the performance of the colored products does not decrease.
03. Dispersant
The dispersant wets and coats the pigment, causing the pigment to disperse evenly in the carrier and no longer agglomerate. Its melting point should be lower than that of the resin, and it should have good compatibility with the resin and good affinity with the pigment. There are many types of dispersants, and low molecular weight polyethylene wax, polyester, stearate, white oil, oxidized low molecular weight polyethylene, etc. can be used.
04. Additives
In addition to coloring, the masterbatch also adds flame retardants, antioxidants, antistatic agents, light stabilizers, etc. according to the various requirements of users, and has multiple functions. Sometimes users do not require it, but masterbatch companies will also suggest adding some additives based on product needs.
3.Color masterbatch production process
The masterbatch production process has strict requirements and can be divided into dry process and wet process.
01. Wet process
Masterbatch is made by grinding, phase transfer, washing, drying and granulation. When grinding and processing pigments, a series of technical tests are required, such as measuring the fineness, diffusion performance, solid content, etc. of the grinding slurry. There are four wet process methods: ink method, flushing method, kneading method, and metal soap method.
02. Dry process
When some companies produce high-grade masterbatch, they prepare pre-dispersed pigments by themselves and then use dry process to granulate them. Color masterbatch production conditions present diversified options depending on product requirements. High speed mixer + single screw extruder, high speed mixer + twin screw extruder are the most common production processes. In order to improve the dispersion of pigments, some companies grind the carrier resin into powder.
Internal mixer + single screw extruder, internal mixer + twin screw extruder are also the process technologies used to produce high-quality masterbatch. At present, masterbatch color measurement and color matching technology has become more popular, and more high-performance spectrophotometers are introduced to assist in completing color matching.
4.Production equipment
Masterbatch production equipment includes grinding equipment, high and low speed kneaders, mixers, extrusion granulation equipment, etc.
The kneader exhausts air, extracts volatile matter and dehydrates through vacuuming and decompression; the discharging methods are cylinder discharging, discharging under the valve and screw discharging; the kneading paddle adopts a frequency converter to adjust the speed.
Mixers are divided into two types: open rubber mixers and closed rubber mixers. Extrusion granulation equipment includes single-screw extruders, twin-screw extruders (parallel corotating, parallel counter-rotating, conical co-rotating, conical counter-rotating), multi-screw extruders and screw-less extruders, etc.
5. Application and development of color masterbatch
Color masterbatch has a wide range of applications, and its main service targets are the plastics industry, rubber industry and fiber industry.
01. Plastic
The pigment content of masterbatch for plastics is usually between 10% and 20%. When used, it is added to the plastic that needs to be colored in a ratio of 1:10 to 1:20 to achieve the coloring resin or product with the designed pigment concentration. Masterbatch plastic and colored plastic can be of the same variety or other compatible plastic varieties.
Masterbatch can be a single color variety or a variety of pigment color combinations. Masterbatch is relatively mature and widely used in the field of plastic products. 85% of the colorants in plastic products use masterbatch. There is no dust flying problem of dry powder pigments, and it completely solves the problems of product color spots and pigment inconsistencies caused by poor pigment dispersion.
In the plastics industry, the market demand for masterbatch is concentrated in engineering plastic products (home appliances, automobiles), construction plastic products (pipes, profiles), agricultural film products, plastic packaging products, etc.
02. Rubber
The preparation method of rubber masterbatch is similar to that of plastic masterbatch. The selected pigments, plasticizers and synthetic resins should be compatible with rubber. Pigments are mainly used as reinforcing agents and colorants in rubber. Black pigments are mainly carbon black; white pigments include zinc oxide, titanium dioxide, calcium carbonate, etc.
Carbon black is widely used in wires, cables, and tires. All traditional carbon black has been replaced by carbon black masterbatch. Its dosage occupies the first position among all color masterbatch.
The use of rubber masterbatch when processing rubber can avoid dust caused by powdery pigments and improve the operating environment. The masterbatch is easy to disperse evenly, making the rubber products uniform in color, and the actual consumption of pigments is reduced.
03. Fiber
Fiber solution coloring is when spinning fibers, the color masterbatch is directly added to the fiber viscose or fiber resin, so that the pigment appears in the spinning, which is called internal coloring of the fiber.
Compared with traditional dyeing, fiber solution dyeing processes resin and masterbatch into colored fibers and then directly uses them for textiles. It has the advantages of small investment, energy saving, no three wastes and low dyeing cost.
Pigments for fiber coloring masterbatch require bright color, good dispersion, good thermal stability, light resistance, solvent resistance, acid and alkali resistance, bleach resistance, insoluble in water, inorganic or organic pigments can be used.
