UV ink innovation in screen printing applications (below)

Opaque pigment inks react differently to UV radiation and energy peaks and UV spectra than non-pigmented UV varnish. Photoinitiators developed for the pigment coating cure generally have higher light attenuation coefficients at longer wavelengths (300-450 nm) than clear coatings. Longer-wavelength light is required for thick UV coatings to achieve full cure, so bulbs It is important that the characteristics match the properties of the coating to be cured. This method optimizes cure speed and overall productivity.

Screen printing equipment manufacturers have also improved their technology, resulting in increased production of machines and shorter installation times. Because of the demand for speed, ink manufacturers have to develop inks with low UV exposure and fast curing speed. Formulating inks that match the spectral output of lamps is the key to successful high-speed printing.

With the latest developments in digital printing, it is envisaged that screen printing will be eliminated, but technical breakthroughs in UV-cured screen printing inks are continuously establishing new performance standards and increasing the speed of digital printing and screen printing. The threshold of competition in versatility. At present, UV screen printing inks can be used in a variety of special products, so that the product has a diverse and decorative appearance, these are beyond the digital 4 color printing.

In the early days of the development of UV inks, the selectivity of the chemical raw materials for formulating the ink was very small, limiting the development of the ink and the scope of application of the ink. In the past 10 years, the function of UV inks has been expanded, raw material suppliers have shown greater interest in the ink market, and today's ink manufacturers can choose from thousands of raw materials. With these improvements, the cooperation between raw material suppliers and ink manufacturers has resulted in many new and innovative inks dedicated to screen printing. The latest developments are as follows:

● Thermoformable UV ink

● Large range of UV inks for various applications (can be used for printing containers, POP images, flags, and signs)

● Thick ink UV ink, such as special flash ink, thixotropic special effect ink, liquid molding substrate ink / electrostatic ink

● Magnetic UV ink

● Flame retardant UV ink

● High hiding power UV ink

● Water resistant UV ink

● special effects imitation metal UV ink

●Long-lasting UV ink

The latest application of UV ink

Recent advances have allowed ink manufacturers to produce UV inks with good adhesion, elongation, softness and water resistance. Recent advances in these ink technologies have had a major impact on the following markets and applications.

POP and display posters

There are multi-purpose POP inks on the market that are firmly attached to a variety of substrates, including paper, cardboard, styrene, stretchable polyvinyl chloride, and even more difficult to adhere polyolefins. In the past few years alone, one-component UV inks have been introduced. They can be attached to polyolefin materials (PE, PP) to meet the softness and water resistance required for flags and similar applications. This new type of ink does not require additives, reducing The ink waste associated with the two-component catalytic curing ink also reduces the amount of ink stored and maintains cost-effectiveness.

Container decoration

Container printing UV ink technology has made the largest progress. The container market particularly needs stable and easy-to-use UV inks. In the past, the ink system on the market was filled with additives and various printing container plastics. Now it is HDPE, LDPE, PET, PVC, PP and other plastics. The containers can be decorated with single-component, additive-free inks. These inks have better hiding power and greatly improved chemical resistance. They do not require additives or catalysts.

Hygroscopic plastic application

Multifunctional monomer is one of the latest developments in UV ink technology, and ink manufacturers are using it to overcome difficulties in printing on hygroscopic materials such as polyethylene and HDPE. These substrates absorb moisture and form a fine barrier between the ink and the substrate, which prevents the adhesion of the ink. Therefore, the printed materials of these materials may be worn or damaged by weather and sand. The ink formulated with the new monomer significantly improves the water resistance on the moisture-absorbing material, the curing speed is fast, the gloss is good, the color is firm, and the printed matter provided is almost waterproof.

Thermoforming

UV inks for thermoforming applications are also relatively new. They have good adhesion and flexibility and can withstand stretching during thermoforming. Thermoformed UV inks can be vacuum formed with a draw depth of 20 cm (8 inches) or more. The improved formula ink can be subjected to thermal bending, stretching, and other post-processing operations on a variety of substrates such as styrene, polycarbonate, acrylics, PETG, PVC, and some metals.

Liquid substrates

The highly ductile resin and the monomers used in thermoforming UV inks can also be used to make new thick-film UV inks, where the formulation is primarily liquid substrates. In other words, these inks can be used as imaging materials as well as printing materials.

Depending on the specific formulation of the ink used, the print can be used to produce pressure sensitive images or electrostatically adsorbed images. This unprinted material method eliminates the need for expensive materials and die cutting costs while reducing contract turnaround time.

Thick ink layer application

A further understanding of the photoinitiator reaction allows the ink formulator to create a myriad of specialty UV inks, including inks that have a high pigment content and can form a thick ink film. They have been considered impossible to cure and have now become a reality. Today, UV inks printed with a 60 mesh/inch coarse screen, 300 [mu]m or thicker photo-sensitive adhesive layer all cure. At present, thick ink layer ink products have thixotropic coatings and inks for drop-molding, and their use is expected to have greater popularity.

Magnetic products

Another ink product from the new thick film technology is a UV ink that can accept magnetic properties. It is suitable for POP applications and can be printed on many substrates to make them magnetic. The ink does not transform the image into an actual magnet, but only the ink printed image is fixed on the magnetic surface. This ink is suitable for applications where newsstands, display racks, shelves and other graphics are easily replaced.

Special effects image

The thick ink UV ink technology has produced many new special effects inks. Flash UV inks contain large, light-emitting materials that produce luminous effects on printed images. They require coarse screen printing to reduce particle dispersion, especially holiday greeting cards and specialized graphics, in a variety of colors. Another recent development is long-lasting fluorescent inks that emit light for up to 14 hours. Other formulations of UV inks are produced with pearlescent, shimmering and metallic particles in a variety of colors for use on a variety of substrates. New inks with high pigment content can be printed on dark surfaces with excellent hiding power, but ink flow and color transmission are limited.

Flame retardant applications

Another hotspot of UV screen printing ink technology is UV flame retardant formula, which is put forward in response to customer concerns about the safety of printed products. Ink and substrate manufacturers collaborate to propose solutions and methods. Although the UV ink has a high ignition point, it will begin to decompose and burn once it reaches the flammability limit. There are two forces that can slow down the process. One is to add flame retardants to the ink so that it reduces or even eliminates the flame. Another method is to formulate a UV ink formulation in the same way as a foamed fireproof coating, so that the UV ink forms an insulating barrier against oxygen, prevents burning, and suppresses flame. However, it is important to remember that UV flame-retardant ink itself cannot completely prevent fire, so the ability of the substrate to extinguish fire is equally important.

With the progress of ink production raw materials, the future development of UV curable products is endless. In the early days, basic UV inks were sold with a range of additives to improve functionality. In order to get proper ink handling performance, printers are forced to act as chemists. Today, ink sales personnel invest more technology into ink and develop products that customers need. Raw material suppliers hope to develop products that ink formulators need. The competition between ink vendors has forced them to find new ways to improve ink performance while developing new areas of profit for UV screen printing. In short, the UV screen printing market has made amazing progress due to the development of UV inks. There is no doubt that with the development of new products and the establishment of new performance standards by raw material suppliers and ink manufacturers, this development trend in the UV screen printing market will certainly continue.