As the second largest user of titanium dioxide, the plastics industry is the fastest growing field in recent years, with an average annual growth rate of 6%
Among the more than 500 titanium dioxide brands in the world, more than 50 are exclusively for plastics
The application of titanium dioxide in plastic products, in addition to its high hiding power, high color reducing power and other pigment properties, it can also improve the heat resistance, light resistance, and weather resistance of plastic products, and protect plastic products from UV light.
Invasion, improve the mechanical and electrical properties of plastic products
Since the coating film of plastic products is much thicker than that of paints and inks, it does not require too high pigment volume concentration.
In addition, it has high hiding power and strong coloring power.
The general dosage is only 3% to 5%
It is used in almost all thermosetting and thermoplastic plastics, such as polyolefins (mainly low-density polyethylene), polystyrene, ABS, polyvinyl chloride, etc.
It can be mixed with dry resin powder or mixed with The liquid phase of the plasticizer is mixed, and some of the titanium dioxide is processed into masterbatch before use
Analysis of the specific application of titanium dioxide in the plastic industry and color masterbatch industry
Most of the titanium dioxide used for plastics has a relatively fine particle size.
Usually the particle size of the titanium dioxide used for coatings is 0.
4μm, while the particle size of the titanium dioxide used for plastics is 0.
3μm, so that the blue base phase can be obtained.
Most yellowish resins or resins that are easy to yellow have a masking effect
Ordinary plastic titanium dioxide generally does not undergo surface treatment, because the conventional hydrated aluminum oxide and other inorganic materials coated titanium dioxide, when the relative humidity is 60%, its adsorption equilibrium water is about 1%, when the plastic is extruded at high temperature During processing, the evaporation of water will cause pores on the smooth plastic surface.
This kind of titanium dioxide that is not coated with inorganic substances generally has to undergo organic surface treatment (polyol, silane or siloxane), because titanium dioxide is used for plastics.
Unlike titanium dioxide for coatings, the former is processed and mixed in low-polarity resin through shearing force.
The organic surface-treated titanium dioxide can be better dispersed under appropriate mechanical shearing force
With the continuous expansion of the application range of plastic products, many external plastic products, such as plastic doors and windows, building materials and other outdoor plastic products, also have high requirements for weather resistance.
In addition to rutile titanium dioxide, surface treatment is required.
This kind of surface treatment generally does not add zinc, only silicon, aluminum, zirconium, etc.
Silicon has a hydrophilic and dehumidifying effect, which can prevent the formation of pores due to the evaporation of water when the plastic is extruded at a high temperature, but the amount of these surface treatment agents is generally not too much
The composition of plastics includes resins, fillers, plasticizers and other additives (such as colorants, antioxidants, flame retardants, etc.
According to the product processing method, it can be divided into extrusion blow molding process of plastic film and extrusion of plastic sheet.
Extrusion molding process and plastic injection molding process, such as:
Extrusion blow molding process of plastic film:
Resins, fillers, and additives masterbatch ingredients (masterbatch plus resin) blown film plastic film
The main equipment used in this process is a double-roll mill and a film blowing machine
The plastic injection molding process includes three stages of plasticization, injection, and molding cooling.
Commonly used equipment includes embolic injection machines, screw injection machines, and so on
The quality requirements of plastic products for titanium dioxide are:
Hiding power: Titanium dioxide with good hiding power makes the plastic products lighter and thinner;
Whiteness: determines the appearance of light-colored or white plastic products;
Dispersibility: It affects the production cost of plastic products.
The poorly dispersed titanium dioxide in plastic products will affect the smoothness and brightness of the products;
Weather resistance: Plastic products used outdoors and plastic doors and windows must ensure the weather resistance of titanium dioxide
Plastic masterbatch is a highly concentrated, high-performance color configuration product, that is, the pigment is uniformly distributed in the carrier resin at an extraordinary concentration and forms particles with a certain particle size
It is mainly composed of core layer (pigment), coupling layer (coupling agent or surfactant), dispersion layer (lubricant or dispersant), mixing layer (carrier resin), etc.
It is used as a coloring agent in plastics, It is widely used in the production of blown film, injection molding, hot pressing, injection molding and other plastic products.
The masterbatch has excellent coloring effect, convenient use, energy saving, and no dust and sewage when used, so it is favored by users
The development speed of color masterbatch is very fast.
In addition, the production process of color masterbatch is simple, and the investment is low.
At present, there are hundreds of domestic color masterbatch factories, and the production scale and technical level are uneven.
Over 10,000 tons, product competition is becoming increasingly fierce, the profits of manufacturers are declining, and the quality of most masterbatch products is low
According to incomplete statistics, the titanium dioxide used in the production of masterbatch is 20,000 to 30,000 tons per year.
The rutile used is divided into high, medium and low grades.
The high grade uses imported rutile, the medium grade uses domestic rutile, and the low grade uses domestic anatase.
Type titanium dioxide
Huizhou Apollo Chemical, China's largest color mesh production company, uses imported titanium dioxide to produce color masterbatches mainly for export, and uses domestically produced titanium white masterbatches to meet the domestic market
Due to fierce competition, the use of anatase-type titanium dioxide color masterbatches is still increasing
Color masterbatch can be used to match colors of PVC, polyethylene, polypropylene, polystyrene and ABS plastics
Its main ingredients are pigments, resins, dispersants, volume pigments, fluorescent whitening agents, antioxidants, anti-ultraviolet agents, antistatic agents, toughening agents, brighteners, etc.
Titanium dioxide is used as a white pigment, with no toxic, chemical stability, high hiding power, good dispersion and so on
There are several production processes for color masterbatch, such as: pigment, resin, dispersant, volume pigment, other additives, high-speed mixer, twin-screw extruding color masterbatch
Color masterbatch is used as an industrial raw material, and its performance is usually manifested in subsequent product applications (such as blown film or injection molding).
Therefore, the performance of titanium dioxide in color mesh particles is mainly reflected in the application process of color masterbatch
Mainly reflected in the following aspects:
1) The coloring ability of titanium dioxide: determine the amount of titanium dioxide used in the same color of plastic products;
2) Whiteness of titanium dioxide: determines the appearance of light-colored (white) plastic products with the same content of titanium dioxide;
3) The dispersibility of titanium dioxide: it affects the production cost of color mesh particles and the appearance and gloss of plastic products;
4) The processing performance of titanium dioxide: affect the production cost of masterbatch