Pearlescent pigments are used for surface treatment of plastic products

Surface treatment usually uses two methods: painting and printing to achieve a decorative effect. The better method of painting is spraying or dipping, so that the wafer arrangement effect is excellent. Printing inks containing pearlescent pigments can also be used.

 Pearlescent pigments can also be used in plastic laser marking technology, manufacturing marbling effects, latex products and casting resins.

The addition of metallic pigments and ordinary iron oxide pigments will reduce its pearlescent effect. Organic pigments with transparency and low hiding power (such as phthalocyanine blue, phthalocyanine green, etc.) are mixed with pearlescent pigments, and its pearlescent effect is better. Other organic pigments with high transparency (such as fast red, quinidone, permanent violet, etc.) are used in conjunction with pearlescent pigments, and its effect is also very good. Carbon black and ultramarine in inorganic pigments are special. Although they are opaque and have high hiding power, they can absorb all the transmitted light and strengthen the reflected light. Therefore, they can also be mixed with special-purpose pigments to produce bright additions. Color effect.

Below are several typical processing methods of plastics and introduce the application of pearlescent pigments in plastics.

Extrusion

Extrusion is mainly used to produce continuous profiles. Such as plastic pipes, rods, wire and cable coatings and plastic profiles, etc. Many pearlescent packaging hoses for facial cleanser, hand cream, and styling hair spray are processed by this method. Hollow blow molding is currently the most widely used and important field of pearlescent pigments. Extrusion technology is now more and more widely used in the manufacture of multilayer composite plastics. Pearlescent pigments are generally limited to the outer decorative layer of the composite film when used for extrusion. The thickness of the colored layer of the pearlescent pigment during extrusion is thinner than that of ordinary extrusion. Correspondingly, the amount of pearlescent pigment should be increased appropriately, generally 8-10%. The actual amount is determined by the thickness of the outer film. The thinner the amount added The higher it is. Its processing process adopts general processing operating conditions, and the pigment flakes are oriented when they are extruded and flowed. This kind of orientation is not affected by surface defects, die and processing equipment. Careful adjustment and various process parameters can obtain a more ideal pearlescent effect. During extrusion, the pearlescent pigment and resin can be mixed uniformly and put into the extrusion. The extruded hose from the machine can also use pearlescent masterbatch, which is mixed into the resin raw material according to the required ratio to produce.

Cast film

     There are many methods for film production. On the extruder, either a round die can be used to produce a cylindrical film by the blow molding method, or a T-shaped die can be used to produce a sheet film by the casting method. Recently, co-extrusion is more popular. Or multilayer composite tubular film. The demand for pearlescent film used in packaging is increasing day by day. Whether it is used in PVC, PET, PE, PP, it has very good results. However, the use of pearlescent pigments in film production has certain requirements. The thickness of the film is generally very thin, and it is easy to be transparent or semi-transparent. An appropriate amount of opaque pigment and titanium dioxide must be added to achieve a certain coverage rate. In principle, when using pearlescent pigments, the above-mentioned pigments should be avoided to avoid affecting the pearlescent effect. This seems a bit contradictory. In fact, in the production of pearlescent films, a certain amount of titanium dioxide is often added in conjunction with pearlescent pigments to make up for the lack of film thickness. And because the film thickness is very thin, the pearlescent pigment flakes are easily arranged neatly and exert the pearlescent effect, but the concentration of pearlescent must be increased correspondingly, about 5-8%. In short, when producing pearlescent film, it is necessary to consider a certain coverage rate and meet the requirements of pearlescent effect. Choose to use double-layer blown film machine to produce pearlescent film. The upper layer is mixed with pearlescent pigments, and the lower layer is used with ordinary opaque pigments. In this way, a pearlescent film with ideal effects can be produced without increasing the concentration of the pearlescent pigment.

Blow molding

    Generally used in the production of various plastic bottles, such as shampoo, hair conditioner, various cosmetics, liquid soap and mineral water, etc. Pearlescent pigments can be directly blended with resins for blow molding. The general usage amount is between 0.5% and 3%, depending on the thickness of the bottle wall to make adjustments. Double-layer or multilayer blow molding can produce hollow products with double-layer product walls. The bottle wall is double-layered, the outer layer contains pearly luster, and the inner layer is ordinary plastic, which can save costs.

Injection molding

        Injection molding products account for 20%-30% of the processing volume of plastic products, and it can form various products with complex shapes. With the development of injection molding technology and machinery, the scope of injection molded products has expanded from civilian use to more fields. The application of pearlescent pigments in injection molding has also developed from various container jewelry and daily necessities to refrigerators, air conditioners, and automotive decorative parts. In recent years, some domestic and foreign manufacturers have applied back-shooting injection molding technology. The pearlescent decorative film is used to produce larger refrigerators, air conditioners and other shells, and even for automobiles, interior and exterior decorations. It has successfully replaced many metal parts, and the effect has made People satisfied.