1. Pigment and dye additives One of the recently invent […]
1. Pigment and dye additives
One of the recently invented anti-counterfeiting technologies uses "color-changing" pigments. These additives contain multiple layers of polymerized light-reflective coatings, which are coated around a reflective aluminum chip to change the color of the plastic with different viewing angles. The change in color, for example, from red to green, is due to the angle of light waves reflected from different pigment layers. Color-changing pigments produce significant aesthetic effects on plastic consumer products, and because these effects are not easily cloned, they also have anti-counterfeiting functions.
One way to identify whether the plastic parts are from the factory is to mix plastic bottles with pigments or dyes, and use a spectrometer to analyze the exposed parts and the ultraviolet area. Those pigments or dyes will show unique patterns. Even if counterfeiters use extremely similar colors on their plastic products, they cannot obtain the same spectrum as the real ones.
Color-changing pigments can be mixed into a variety of resins, such as pc, pp, hdpe, pet, abs, thermoplastic pu, cellulose acetate and pa12. The weight ratio of the color-changing pigment in the resin is usually between 0.2% and 0.4%, and can be processed by standard processes such as injection molding, extrusion blow molding, thermoforming, calendering, extruded film and in-mold decoration.
2. Particle identification
The purpose of developing micro-signs at the beginning was to help track the source of explosives in the event of a *** incident, but today it is widely used to track and identify the authenticity of plastic products. The most typical particle identifications are those with a specific resolution of color stripe patterns or polymer particles containing special chemical components. These particles can be mixed with thermoplastics before molding. The marked particles are often mixed with plastic powder in advance so that they can be used for molding or concentrated, and can be molded by diluting it during processing. The color bar micro-marks on the plastic parts of injection molding, extrusion molding or rotomolding can be clearly distinguished by scanning through a microscope or a pattern discriminator. Some manufacturers make the logo fluorescent or magnetic, so that it can be easily distinguished from authenticity by using an ultraviolet irradiator or a magnetic scanner.
The diameter of the particles is less than 50 microns (equivalent to the size of bacteria), and the larger is about 600 microns (equivalent to the size of salt particles), which are different. These particles are inert, usually do not react chemically, and can withstand the high temperatures during molding without damage. By changing the number, model and color combination on each particle or changing the chemical properties of the particle surface, millions of various unique coding mixtures can be produced. Because the resin contains coded particles, the manufacturer and product information can be identified with a special barcode reader.