Functional ink performance and use (on)

A brief introduction to various functional inks

1 resist ink. Resist inks are inks that have chemical resistance. Its role is to print in advance on the part of the workpiece without treatment (corrosion, electroplating, welding, etc.) to form a corrosion-resistant (or plating, solder resist) film layer. Representative inks include corrosion-resistant inks, plating-resistant inks, and solder resist inks used for the production of printed circuit boards.

a. Corrosion resistant ink. This is an acid-resistant, resist ink, available in UV, solvent, and water-based types. UV inks have become mainstream due to the high efficiency of printing operations. After printing, UV curing is performed, and corrosion is performed with ferric chloride and copper aminide, and then the resist ink is stripped or swollen with a dilute alkali. The water-based type is generally used as a corrosion-resistant film of an aluminum evaporated film.

b. Electroplating ink. When manufacturing a printed circuit board, in the electroplating process, the electroplating ink that does not need to be electroplated is an electroplating-resistant ink, a solvent-type plating-resistant ink, and a UV-type plating-resistant ink.

c. Solder resist ink. Solder resist ink is printed on circuit boards that are used to make circuits and graphics. Its role is to prevent circuit corrosion, prevent insulation degradation due to moisture, prevent solder from adhering to unwanted parts, and prevent copper from soldering. Pollution and so on. This ink has a thermosetting and UV type.

2 conductive ink. Conductive ink is a pasty ink made by dispersing conductive fillers such as gold, silver, copper and carbon in a binder, commonly known as paste ink. Gold-based conductive inks, silver-based conductive inks, copper-based conductive inks, and carbon-based conductive inks have been put to practical use for printed circuits, electrodes, plating bottom layers, keyboard contacts, and printed resistors.

a. Gold conductive ink. Gold powder has stable chemical properties and good electrical conductivity, but it is expensive and its use is limited to thick film integrated circuits.

b. Silver conductive ink. A large number of conductive prints for membrane switches. When the printing material is polyester, the silver powder can be dispersed into the polyester resin binder to form a conductive paste ink. When the ink film is poorly dried, the resistance value will drop, and it is best to use a far-infrared dryer to dry it at 120-130°C.

c. Copper conductive ink. Copper is cheaper than silver, but it has the disadvantage of being easily oxidized. Nowadays, copper powders that have been subjected to oxidation-proof treatment are often used. Circuits printed using such inks are not easily oxidized, but the disadvantage is that once high-temperature treatment is performed, the anti-oxidation effect is lost.

d. Carbon-based conductive ink. The fillers used in the carbon-based conductive ink include conductive channel black, acetylene black, furnace black, and graphite, and the resistance level varies depending on the type. Mostly used for membrane switches and printed resistors, the former are mostly printed on the polyester substrate, so it is the same as the silver conductive ink, using polyester resin as the link material ink.

3 Insulation ink. The ink is used to prevent displacement and contamination of the silver-based conductive ink. Insulating inks are solvent type and UV type. The former uses vinyl resins or polyester resins as the binder. UV ink film thickness is good for improving insulation resistance and preventing circuit displacement.

4 foaming ink. Foaming ink is made by adding a capsular foaming agent to the ink binder. After printing, foaming is performed by heating to increase the volume of the inked portion to form a relief-like image. The linking materials for foamed inks are aqueous and solvent based. In order to encapsulate the foaming agent, an aqueous vehicle is generally used. Blowing agents are mostly acid lanthanide compounds, whose decomposition temperature is 100 to 200°C, generally 100 to 150°C, and their foaming magnification. If the substrate is cloth or paper, it can be 100 to 500 times. As the expansion ratio increases, the adhesion and strength of the ink film decrease. When printing, it is generally used

A screen size of about 100 mesh is best for thick film printing.

Since the foamed ink uses an aqueous binder, it is easy to use and has no pollution. The screen ink permeability and image reproducibility of the foamed ink are all good, and the ink film has the advantages of good solvent property, drug resistance, abrasion resistance, and no deformation under heavy load.

The micro-capsule foam in the foamed ink is a thermoplastic polymer particle. It has a "hollow" shape and is generally formed by polymerization of polyvinylidene chloride or vinylidene chloride and acrylonitrile, or acrylic methyl and acrylonitrile. The hollow part contains a volatile foaming agent, and the foaming agent is mostly carbon compounds such as ethane, propane, and butadiene. Microcapsules are generally between 5 and 150 microns in diameter. The content of the microcapsule foam in the ink is generally 5 to 50%, the content of the microsphere foam is low, and the foaming effect is not good. If the content is not high, the ink fluidity is reduced, and the ink film is not uniform. b

The foaming ink should be fully dried after printing, dried naturally and forced dry. In order to obtain an exquisite printing effect after the foam is foamed, if the method of natural drying is adopted before foaming, the drying time should be more than 24 hours. Forced drying is shorter and faster than natural drying. When forced drying, it should be noted that according to different prints and different drying heat sources, select the appropriate drying temperature and time. If the drying time and temperature are not properly selected, it is easy to cause uneven foaming. The forced drying temperature is between 30 and 70°C. After being dried, it can be foamed, the foaming temperature is controlled at about 120°C, and the corresponding foaming time is considered. Foaming equipment can be used baking oven can also use baking machine, foaming rate up to 8 to 15 times.

Foaming ink is widely used in the embellishment of clothing and textiles. It has a uniform pattern of cells, a strong three-dimensional impression, and a soft and comfortable feel. It is similar to artificial embroidery and applique, and it is also characterized by wear resistance and water resistance. Foaming inks are also used for braille printing, book cover decoration, trademark packaging and decoration, interior decoration materials, and other art products.

In recent years, China has also begun to introduce and produce foaming inks, such as Sorgol brand foam printing pastes produced by Beijing Segor Foam Coatings Co., Ltd. The product is milky white, good fluidity, good lubricity, non-toxic, non-flammable, non-corrosive and so on. The drying temperature is below 50°C, the foaming temperature is 120±5°C, and the foaming time is 2～1Q seconds. It is suitable for the 140-mesh screen printing plate, and can be used for any kind of printing and dyeing coating color paste ( The addition amount is preferably 2 to 5%, and can be printed on any kind of garment fabric, and can also be used for wallpaper, wall covering, book cover, Braille, and bag decoration.

5 liquid crystal ink. Liquid crystals, ie liquid crystals, are an intermediate state that certain organic substances present within a certain temperature range. In this state, the alignment of the molecules of the material is azimuthal.

Under the action of electricity and heat, the optical properties of liquid crystals will change. Liquid crystals are sticky liquids, and organic solvents destroy their functions. Therefore, the inks are encapsulated when they are manufactured. The particle size of the liquid crystal capsule is 10 to 50 μm, and the amount added to the binder is 25 to 50%. It is very important for the color development of the ink to form a uniform film thickness during liquid crystal printing.

6 fluorescent ink. Fluorescent inks for screen printing use inks made from fluorescent pigments as a coloring material. Fluorescent pigments are made from fluorescent dyes and synthetic resins, with particle sizes between 5 and 15 microns.

Fluorescent inks for screen printing are suitable for the printing of paper and vinyl films. There are two types of paper-based fluorescent inks: oxidative drying and evaporation drying. The fluorescent film for the ethylene film is an evaporation-drying type.