A brief discussion on the packaging technology of cosmetics

As one of the important fulcrums of cosmetics, color cosmetics have higher requirements for the visual effects and touch of cosmetics. Compared with other packaging materials, color cosmetics have more stringent requirements for the process of cosmetic packaging materials.

Designing the appearance process of cosmetic packaging materials is an important part before a cosmetic is put on the market, which cannot be omitted. At present, the main processes of cosmetic packaging materials on the market are: electroplating, silk screen printing, hot stamping, surface spraying, UV, thermal transfer, and sandblasting. Then let’s follow Yusu Packaging to analyze the mainstream processes of cosmetic packaging materials:

1. Electroplating process

Electroplating process: Electroplating refers to a surface processing method in which the cations of the metal to be plated in the plating solution are deposited on the surface of the base metal through electrolysis in a salt solution containing the metal to be plated, with the base metal to be plated as the cathode, to form a coating. The coating performance is different from the base metal and has new characteristics. According to the function of the coating, it is divided into protective coating, decorative coating and other functional coating.

Electroplating process: generally includes three stages: pre-treatment before electroplating, electroplating and post-plating treatment. Requirements for electroplating:

1. There should be good bonding between the plating and the base metal, and between the plating and the plating.

2. The plating should be finely crystallized, flat, and uniform in thickness.

3. The plating should have a specified thickness and as few pores as possible.

4. The plating should have the specified indicators, such as brightness, hardness, conductivity, etc.

2. Screen printing process

Screen printing refers to using a screen as a base and making a screen printing plate with images through a photosensitive platemaking method. Screen printing consists of five major elements: screen printing plate, scraper, ink, printing table and substrate. Printing is based on the basic principle that the mesh holes of the screen printing plate with images can pass through the ink, while the mesh holes of the non-image part cannot pass through the ink. When printing, pour ink at one end of the screen printing plate, use a scraper to apply a certain pressure to the ink part on the screen printing plate, and move at a constant speed toward the other end of the screen printing plate. The ink is squeezed from the mesh holes of the image part to the substrate by the scraper during movement.

3. Hot stamping process

The hot stamping process includes:

Hot stamping preparation → plate mounting → plate pad → determination of hot stamping process parameters → hot stamping → sample signing → formal hot stamping.

Hot stamping is a special printing process that does not use ink. Hot stamping refers to the process of hot stamping anodized aluminum foil onto the surface of the substrate under a certain temperature and pressure.

The graphics and texts of the anti-counterfeiting electroplated aluminum hot stamping on packaging present a strong metallic luster, with bright colors and never fade. In particular, gold and silver electroplated aluminum, with its magnificent, exquisite and elegant decoration, embellishes the surface of printed materials, enhances the artistry of printed materials, and plays a propaganda effect of highlighting the theme; its brightness greatly exceeds that of gold and silver printing, making the product feel high-end and giving people a beautiful enjoyment. At the same time, because electroplated aluminum has excellent physical and chemical properties and plays a role in protecting printed products, the hot stamping process is widely used in high-end and exquisite packaging decoration trademarks, calendars and book covers and other printed materials; secondly, the scope of hot stamping of electroplated aluminum is very wide, from general book covers, trademark patterns, publicity advertisements, plastic products to daily necessities, from paper to leather, cotton cloth, etc.;

Hot stamping is a dry processing method, and the workpiece can be immediately packaged and transported after hot stamping. Therefore, hot stamping technology is currently widely used in pre-press processes, and the scope of application of hot stamping is still expanding.

4. Surface spraying

The four major elements that make up the coating include:

1. Resin;

2. Pigment;

3. Solvent;

4. Other additives.

There are several types of coating drying:

1. Volatile drying (using diluent evaporation drying);

2. Fusion drying (molecules polymerize due to evaporation resistance);

3. Oxidative drying (unsaturated fatty acids combine with oxygen in the air);

4. Drying by bridging reaction (using bridging agents, so-called hardeners, to form bridges and harden);

5. Ultraviolet hardening (unsaturated polyesters are added with agents and then irradiated with ultraviolet wavelengths of 300-400mn and the molecules polymerize and harden).

5. Introduction to UV technology:

UV coatings can be applied by dipping, pouring, painting, spin coating, and even vacuum coating, and then cured into films by ultraviolet photons. Compared with general solvent-based coatings, the characteristics of UV coatings are as follows:

1. Fast curing speed;

2. Curing at room temperature;

3. Energy saving;

4. Saving floor space;

5. No pollution to the environment;

6. Improving product performance.

6. Thermal transfer

Thermal transfer is a technology that prints patterns or designs on heat-resistant adhesive paper, and prints the patterns of the ink layer on the finished material by heating and pressurizing. Even for patterns of multiple colors, since the transfer operation is only a process, customers can shorten the printing pattern operation and reduce the loss of materials (finished products) caused by printing errors. Using thermal transfer film printing, multi-color patterns can be drawn at one time without color registration, and simple equipment can also print realistic patterns.

Thermal transfer equipment is used to decorate aluminum profiles and various metal plates, and can achieve the effect of wood products or marble. The thermal transfer equipment works according to the principle of thermal sublimation. It can quickly transfer the required wood grain or marble grain to the surface of the aluminum powder coating within 3-5 minutes and can penetrate 40-60 microns into the coating. Aluminum transfer production process: First, use a film machine to cut the thermal transfer film roll to the required size. Second, use a transfer ultrasonic packaging machine to ultrasonically weld the cut transfer film into a workpiece wrapping bag according to the size of the workpiece. Third, insert the workpiece into the workpiece wrapping bag made of transfer film on the packaging platform. Fourth, place the workpiece wrapped with transfer film on the trolley platform of the thermal transfer machine. 18 aluminum materials can be placed in sequence. Connect the vacuum taps at both ends of the aluminum material and lock them. Turn on the vacuum switch. At this time, the transfer film is tightly attached to the aluminum material. The trolley automatically delivers the aluminum material to the baking furnace. The baking furnace automatically heats up to 220 degrees and keeps warm for 3 minutes. The trolley automatically exits the baking furnace. Fifth, release the vacuum tap and remove the workpiece. Sixth, remove the transfer film and check the quality of the workpiece.

The production process of flat thermal transfer is as follows: first, use a film cutter to cut the thermal transfer paper roll into the required size. Second, attach the thermal transfer paper film to the surface of the workpiece and place it on the flat thermal transfer machine. Third, push the flat plate to the heating area of ​​the flat thermal transfer machine, press the pressure plate switch, and the pressure plate presses the thermal transfer paper tightly on the workpiece, heats and keeps warm for one minute. Fourth, raise the pressure plate, push the workpiece to the workpiece section, remove the transfer film, remove the workpiece and check it.

Thermal transfer technology is widely used in electrical appliances, daily necessities, building materials and decoration. Almost all products are made of labels in this way because of its corrosion resistance, impact resistance, aging resistance, wear resistance, fire resistance, and no discoloration for 15 years when used outdoors. For example, when you open the mobile phone case, you can see densely packed labels with barcodes inside. Many labels are required to withstand the test of time, not deform or fade for a long time, not wear out due to contact with solvents, not deform or discolor due to high temperature, etc. Therefore, it is necessary to use a special printing medium and printing material to ensure these characteristics, which cannot be achieved by general inkjet and laser printing technology.

VII. Sandblasting

Sandblasting is very common on metal surfaces. The principle is to impact accelerated abrasive particles against the metal surface to achieve rust removal, burr removal, oxide layer removal or surface pretreatment, etc. It can change the finish and stress state of the metal surface. Some parameters that affect sandblasting technology need to be paid attention to, such as abrasive type, abrasive particle size, spray distance, spray angle and speed. In addition to sandblasting, shot blasting is also a good choice.

The sandblasting process can be divided into two types: air pressure spray gun and impeller shot blasting. The advantage of the sandblasting process is that it can remove the peaks, remove the burrs after die casting, stamping, flame cutting and forging, and has better effects on thinner workpieces and burrs with pores. It can clean the residual sand particles in the sand casting process, clean the rust stains of cast iron or steel, and remove the oxide scale after heat treatment, burning, hot forging, rolling and other hot processes. In addition, in coating applications, it can remove the existing coating or protective layer, and provide a glossy surface for defects such as cracks or cold lines on the covered castings. In addition, in terms of surface stress, it can provide a consistent roughened surface, oiling and spraying effect. When high-stress metal parts such as springs and connecting rods are continuously knocked locally, they will deform and show a strengthening phenomenon. This strengthening effect requires the use of round abrasives such as stainless steel shots, and is used in high-energy shot blasting machines or special powerful sandblasting machines. If you want to measure the surface strengthening effect of the machine, you can shot blast or sand blast the test workpiece, and then measure whether the deformation meets the requirements.