Functional ink properties and use (below)

The following points should be noted when using fluorescent inks.

a. Due to the poor lightfastness of fluorescent inks, it is not suitable for long-term outdoor use. Therefore, fluorescent screen printing inks should not be used for screen printing products used outdoors.

b. Fluorescent inks are suitable for screens up to 200 mesh.

c. When the ink content of the printed matter is 50 to 60 g/m2, the hair color and light resistance are ideal.

d. When the substrate is a transparent object, white ink should be printed before printing fluorescent ink, which can improve the fluorescence effect.

In general, fluorescent inks are easily confused with luminous inks and can generally be distinguished by comparing the characteristics of the two inks.

7 perfume ink. Similar to liquid crystal inks, perfume inks are inks made by microencapsulating oily flavors and dispersing them in aqueous vehicles. After the printing is dried, the printed portion is rubbed with a nail or a hard substance, and the microcapsules are destroyed and emit a fragrance.

8 flash ink. Randomly arranged flake pigments are dispersed in the binder to produce flash ink. The flake pigments in this type of ink reflect specularly on the light and create a flash effect. Such as pearlescent and color foil flash ink.

9 reflective ink. The ink formed by ultra-fine particles (between 0.125 and 0.177mm in diameter) of glass powder, with the help of lens refraction and concave spherical reflection, causes the ink film to produce a high reflectance and strong light when the light is illuminated. The white ink's reflected light is 100 to 200 times lighter and does not produce glare. It is commonly used to print traffic signs and clothing.

UV color ink. Ultraviolet color-developing inks can only see milky white under sunlight and general lighting, and can emit bright fluorescence when exposed to ultraviolet light. The color-developing material uses an inorganic phosphor and is dispersed in a binder in accordance with the purpose to make ink.

Compared with general fluorescent inks, this ink has good heat resistance, solvent resistance, light resistance, and chemical resistance. Divided into solvent type and water type. When used, the solvent type is a screen printing plate of 100 to 200 mesh, and the water-based printing plate is a screen printing plate of 80 to 100 mesh.

The standard colors are green, yellow, orange, red, pink, purple, blue, and white. After mixing, a variety of colors can be adjusted.

The light sources for color development include fluorescent tubes, light bulbs, and concentrators.

The purpose of the UV color ink is: display billboards, display devices, interior decoration, ultraviolet imaging paper, clothing, stationery, toys, trademarks, anti-counterfeiting and so on.

10 Photochromic inks. Photochromic substances, under the effect of light, can produce reversible changes between the two colors and form different absorption spectra accordingly.

Substances that exhibit photochromic properties are called photochromic pigments, and most of the hair is spirocyclic adducts. This type of compound is made into an ink, which is a photochromic ink.

Its use is dimming (shading, color filtering). Can be used to make sunglasses, door and window glass, in the industrial and display applications are being developed.

Photochromic inks are solvent-based and can be formulated to suit a variety of substrates. The disadvantage is poor lightfastness.

@ Transfer ink. Transfer methods include thermal transfer, wet transfer using water or solvent media, and pressure-sensitive transfer by pressure. Thermal transfer and pressure-sensitive transfer can also be referred to as dry transfer.

a. Thermal transfer. There are mainly hot-melt transfer printings that transfer all the components of the printing ink film, and sublimation transfer printing that sublimates and dyes one of the components of the printing ink film. In screen printing, hot melt transfer is more. Hot melt transfer inks include plastic melts, waxes, and thermoplastic resins.

Plastic melt glue. It is a heat-curable ink with a paste-like resin as its main component. Print on transfer paper. Heating is performed at a temperature of 100 to 120° C. for 30 to 60 seconds to dry the ink. A hot press is used during the transfer, and the cloth and the transfer paper are overlapped, heated at a temperature of 170 to 190° C., and hot-pressed for 15 to 20 seconds. The transfer film is a thick film with rubber-like elasticity. Hot melt inks can be printed directly on the fabric.

Wax system. Ingredients are hot melt adhesives for waxes, pigments, and desiccants. Waxes come in many varieties with their own melting points and tackiness. The tackifier is preferably one that imparts fluidity to the ink while having good fusibility with the wax and good adhesion to the fabric. The transfer paper is coated with a paste as a base layer, and then the ink is printed, and finally coated with the paste in the outer layer. The cloth and the transfer paper are overlapped, and they are transferred with a 150°C iron for 3 to 5 seconds by hot pressing.

Reaction system. This ink can be used for direct printing of cloth. Thermal transfer inks are used as binders for flocking transfer. However, flocking transfer printing is a relatively expensive printing method. Due to the good adhesion and fastness of the reactive inks, they are often used.

The ink is an O/W emulsion with cross-linking properties. The main agent and the cross-linking agent are mixed, the catalyst is added as needed, and printing is performed on the flocking transfer paper. The transfer paper and the cloth were overlapped and transferred by pressing at 150°C for 3 minutes.

Thermoplastic resin system. The thermoplastic resin ink is a general volatile drying ink, and the type of plastic to be transferred is selected in accordance with the ink.

In this type of transfer, a pattern is printed on a soft film such as polyester or polyethylene with good releasability, and a transfer printing paste is printed thereon. Then put it into the model, and then inject the resin solution, remove the pattern from the cooled model and transfer it into a molded product. In this way, even complex shaped products can be transferred. It is characterized by the fact that it is also possible to perform transfer printing on plastics that are difficult to bond.

Sublimation transfer ink. It is a kind of ink with sublimation dye as color material, it is sublimated and evaporated by heating, and it is transferred to fiber products. The order of easy-to-color fibers is polyester, nylon, and propylene, but as a printing material, polyester is basically a market. The transfer conditions were 200°C and 30 to 40 seconds. Transfer pressure to 0. l~0.2kgf/cm2 is the most suitable. The sublimation transfer method is mainly used for offset printing and gravure printing, with less screen printing.

b. Pressure-sensitive transfer. Also known as dry printing or dry transfer printing. In this method, a pattern is printed on a film, and then a pressure-sensitive transfer adhesive is coated on the pattern. During transfer, the film is overlapped with the paper, and the pattern portion is transferred from the polyethylene film to the substrate by pressing with a tool. on.

c. Wet transfer. Wet transfer printing media generally use water and alcohol solvents.

Water transfer printing inks are used in ceramics, woodware, and plastics. We only describe the wood and plastic water transfer inks. The dextrin was coated on paper to make a transfer paper. After the transfer paper is wetted with water, the dextrin is dissolved, the pattern is detached from the transfer paper, and the pattern is slid for transfer. Therefore, water transfer is also called sliding transfer. Ink uses nitrocellulose ink. When printing, print according to the pattern color sequence.

Solvent transfer is a method of replacing water with an alcohol-based solvent. Mainly used for metal and coating metal. Encapsulated paper coated with shellac can be dissolved by alcohol. The printing method is the same as the water transfer method. The ink is an ink resistant to alcohol and weather.

There are various types of functional screen printing inks. In addition to the above, there are also strippable inks for printing of the lottery coupons, thermochromic inks for printing thermostats, and the like. As for printing materials made by users themselves, it is even more unknown. Such as printing silicone rubber keys for silicone screen printing inks, superconductive paste for screen printing superconducting components, chocolate paste for printing and pasting, red phosphorus printing inks for printing matchboxes, etc., this book will not be introduced one by one.