Basic knowledge of color matching and process of plastic bottles(1)


Color matching is based on the three basic colors of re […]

Color matching is based on the three basic colors of red, yellow, and blue (three primary colors), to match the color that is pleasing, meets the color difference requirements of the color card, meets the color desired by the customer, is economical and does not change color during processing and use.
Pigments and dyes
Pigment characteristics: Pigments are colorants that cannot be dissolved in common solvents. Therefore, to obtain ideal coloring properties, it is necessary to uniformly disperse the pigments in the plastic by means of mechanical heating and mixing.
Pigment classification: According to the structure of pigments, it can be divided into organic pigments and inorganic pigments.
Inorganic pigments:
Advantages: good thermal stability, very good weather resistance, excellent light stability, low price, and superior dispersion performance. For example: titanium dioxide, carbon black, etc.
Titanium dioxide series: mainly include titanium dioxide, zinc oxide, and lithopone. Titanium dioxide has two structures: rutile and anatase. Rutile titanium dioxide has high refractive index, high hiding power, stability and good weather resistance. If the titanium dioxide is not dispersed in the original factory, a large number of black spots will be produced during the color matching process. It is in the state of dispersing and not opened, so it can be used after dispersing processing with a dispersant. Some manufacturers’ brands are processed after processing. When entering the market, such materials can be used directly. It is mainly used to cover the transmittance of resin and increase the whiteness.
Carbon black: It is a commonly used black pigment with low price. In addition, it has UV protection (anti-aging) effect and conductive effect on plastics. Different production processes can obtain various carbon blacks with a wide range of particle sizes, and their properties vary greatly. . Carbon black can be divided into pigment carbon black and rubber reinforcement carbon black according to its purpose. Pigment carbon black can be divided into high pigment carbon black, medium pigment carbon black and low pigment carbon black according to its coloring ability. Carbon black particles are prone to agglomeration. To improve the coloring power of carbon black, and to solve the dispersibility of carbon black, it is necessary to add a dispersant for processing before it can be used.
Organic pigments:
Advantages: high tinting strength, bright color, complete chromatogram, low relative density, small addition amount.
Disadvantages: Inferior to inorganic pigments in terms of heat resistance, weather resistance and hiding power, poor dispersion effect, poor transparency relative to dyes, and higher prices.
Advantages: Dyes are organic compounds that can be used in most solvents and dyed plastics. The advantages are low density, high coloring power, and good transparency.
Disadvantages: But its general molecular structure is small, and it is easy to migrate during coloring (crystalline material). The price is more expensive than inorganic, and the price of some is close to that of organic pigments.
Pearlescent Pigment
Also called mica titanium pearlescent pigment, it is a kind of mica wafer coated with titanium dioxide. According to different hue, it can be divided into three types: silver-white pearlescent pigments, rainbow pearlescent pigments, and colored pearlescent pigments.
When purchasing pigments, you must understand the dye index (CI) of the pigment. CI is an international collection of dyes and pigments compiled and published by the British Dyeers Association and the American Textile Chemists and Dyeers Association. Each type of pigment is based on application and chemistry. The structure category has two numbers to avoid misunderstanding of the same molecular structure and different names when purchasing, and it is also conducive to the management of colors and the use of correct pigments to find the cause when problems occur.