Surface treatment process of plastic

     Plastic surface treatment is the use of physical, chemical, mechanical and other methods to process the surface of plastic.

Surface treatment is to meet the special requirements of products, such as corrosion resistance, wear resistance, decoration or

other special requirements, called secondary processing; The secondary processing of plastic surfaces is divided into four

categories: printing, laser, coating, and electroplating.

     1、 Printing

     Printing on plastic surfaces includes screen printing, transfer printing, heat transfer printing, hot stamping, etc;

     The principle of silk screen printing: Silk screen printing is achieved by squeezing ink through the holes in the graphic and

text parts of a scraper to transfer it to the substrate, forming a graphic and text image similar to the original.

     The principle of transfer printing: Transfer printing, also known as curved printing, is the process of first placing ink into an

engraved intaglio with text or patterns, then copying the text or patterns onto rubber, and then transferring the text or patterns

onto the surface of a plastic molded product using rubber. The ink is then cured by heat treatment or ultraviolet light irradiation.

     The principle of heat transfer printing: The pattern is printed on a special release paper with sublimation ink in advance, and

then transferred to a plastic film. The advantage of heat transfer printing is to transfer the pattern or pattern from the adhesive

film or paper film to the working surface with heat. The transfer printing or hot stamping process only requires one hot

stamping of the printed object to transfer multiple color patterns onto the adhesive. This can reduce the defect rate of adhesive

parts, and the pictures are exquisite, which can be completed with ordinary hot stamping machines and heat transfer printers.

Simple operation, exquisite printing, and low production cost. The product has low loss, high added value, and strong decorative

craftsmanship. High coverage and strong adhesion. Compliant with green and environmentally friendly printing standards, with

no environmental pollution.

     The principle of hot stamping printing: Hot stamping is the use of specialized foil to transfer text and patterns onto the

surface of plastic products at a certain temperature; The advantage of this method is that it does not require surface treatment

and can be color printed using a simple device. In addition, products with metallic luster such as gold and silver can also be

printed.

     2、 Laser

     Laser engraving, also known as laser printing technology, is a printing method that uses the high energy held by lasers to

directly print text and patterns on the surface of materials. According to different printing methods, it can be divided into

scanning laser machines and shielding laser machines.

     The principle of a scanning laser machine: The scanning laser machine uses two lenses equivalent to the X-axis and Y-axis to

control the laser light and print the desired pattern or text on the substrate; The advantage is that it is good at printing small

text; The drawing data is controlled by a computer and is suitable for low batch production.

     The principle of shielded laser machine: When using a shielded laser machine, the pattern and text to be printed must be

made on a template in advance, and then the laser is passed through the template to carve according to its projection; The

advantage is that the time required for each printing is extremely short, making it suitable for mass production.

     3、 Painting

     Painting is the process of applying paint onto an object to form a solid coating, which can prevent or delay external damage

to the object and extend the lifespan of the material. Painting also has a decorative function, giving color to the surface of the

object being painted, which can result in various appearance effects; The coating also has special properties, such as anti-static,

anti-corrosion, insulation, etc.

     4、 Electroplating

     Simply put, plastic electroplating refers to the electrolytic reaction in a solution using external direct current to deposit a

metal or alloy layer on the surface of the plastic. The product coated by vacuum coating at a high vacuum degree involves

placing the coated film substrate in a vacuum evaporation machine, using a vacuum pump to evacuate the coating to a vacuum

degree of 1.3 × 10-2~1.3 × 10-3Pa, and heating a crucible to melt and evaporate high-purity aluminum wire (99.99% purity) into

gaseous aluminum at a temperature of 1200 ℃~1400 ℃. Gaseous aluminum particles deposit on the surface of a moving thin

film substrate, and after cooling and reduction, form a continuous and bright layer of metallic aluminum.