Factors affecting printing quality of pad printing ink and its classification application?

Factors affecting printing quality of pad printing ink and its classification application

In pad printing, ink is usually considered as the most critical factor affecting printing quality.

However, the control of other factors is also very important. Printers often attribute printing problems caused by other factors to ink, and sometimes they can't solve the problem for several hours, mainly ignoring the influence of other variables such as mechanical settings and environmental conditions.

Therefore, printers should thoroughly understand the process of pad printing and the role of ink, and take all factors affecting quality into account when problems arise, instead of blindly looking for ink problems.

Special pad printing ink is different from general solvent-based ink, water-based ink and UV-curable screen printing ink. Although pad printing ink and screen printing ink have some similar characteristics, there are still great differences.

Different from screen printing ink, pad printing ink dries faster, which is also the most prominent feature of pad printing ink. At the same time, pad printing ink is often printed on film, which makes pad printing ink vulnerable to temperature, humidity, static electricity and other factors.

All pad printing inks contain binders, pigments, diluents and some additives. Binder is the main body of ink, and typical binder systems include epoxy resin, vinyl resin and polyurethane resin. Pigment is a kind of powdered colorant, which is dispersed in the binder to give ink color and opacity. Diluent is mainly used to adjust the viscosity of the mixture of pigment and binder, and to adjust some printing characteristics of ink. The function of additives is to adjust the characteristics of ink, such as fluidity and surface characteristics. In order to ensure the success of pad printing, the ink must be well controlled and fixed on the substrate in a short time.

In short, only by adjusting the ink components listed above can the printing effect be the best.

Types of pad printing ink

There are several kinds of special ink for pad printing, including single-component ink, two-component ink, dry ink, oxidized ink and sublimation ink.

One-component ink

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One-component ink (also called solvent evaporation ink) is dried by solvent evaporation, and this ink does not need to add catalyst (some inks have catalysts, others do not). One-component ink has two types: glossy and matte, which are mainly used for plastic printing.

Two-component ink

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Two-component ink is also called chemically reactive ink, and catalyst must be added before printing. The catalyst reacts with the resin in the ink and dries the ink by polymerization. However, during the chemical reaction called "adaptation period" of ink, no solvent volatilizes.

When pad printing uses two-component ink, it is necessary to add a certain proportion of catalyst, usually measured by quality (weight). The addition ratio of catalyst must be strictly controlled, too much will greatly shorten the "adaptation period" of ink; Adding too little may cause the ink to fail to achieve the best drying performance when drying. Generally speaking, if the proportion of ink and catalyst is improper, it will lead to printing defects such as uneven adhesion of ink and insufficient durability of printed images. After the "adaptation period" of ink has passed, although adding a certain amount of solvent may make some remedies, it is impossible to get an acceptable printing effect, so it is better to change the ink.

Dry ink

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There are two kinds of dry ink: one is to add a catalyst on the basis of standard two-component ink; The other is to prepare ink specially for glass, ceramics, metals and other substrates. As the name implies, dry ink must be heated and dried at a certain temperature. When using this ink, the drying time should be calculated. The higher the temperature, the shorter the drying time. However, if the drying temperature is too high, the ink film will become brittle, so it is necessary to dry the ink at a temperature that can maintain the flexibility of the ink.

Oxidized ink

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Oxidized ink absorbs oxygen in the surrounding environment and polymerizes to form ink film without adding catalyst. Typical applications of oxidized ink are soft packaging and printing of synthetic materials, such as rubber products or keyboards. Because the drying speed of oxidized ink is slow and takes a long time, its use is limited.

Sublimation ink

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Sublimation ink needs special treatment in the process of use, that is, it needs to be heated after printing, so that the substrate is porous, so that when the dye touches the heated substrate surface, the dye in the ink becomes gaseous and enters the substrate surface, which actually changes the surface color of the substrate. Once the substrate is cooled, the ink will stick to the surface of the substrate. The most common application of sublimation ink is computer keyboard printing, as well as those that require high oil resistance and wear resistance, which cannot be realized by using two-component ink. It is particularly noteworthy that because sublimation ink actually changes the surface color of the substrate, the color between the substrate and the ink is difficult to match, so the color of the substrate must be lighter than the color required for final printing, because the color change of sublimation ink on the surface of the substrate with deeper color is often not obvious.

Special inks and additives

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Other inks with limited uses, such as edible ink, silicone ink, lubricating ink, corrosion-resistant ink, conductive ink and UV curing ink, can also be used for pad printing. The ability of these inks to quickly become sticky will determine whether the ink can be effectively transferred to the surface of the substrate. At the same time, in order to adjust the printability and performance of the ink, in addition to adding solvents and catalysts,

Besides chemical reagents, many additives can be used, such as viscosity regulator, electrostatic control agent, rheological agent, etc. However, the use of additives will have a great impact on the printing performance of ink, so we must be careful when using it.

Dongguan Jiasheng Ink Factory is a standardized enterprise specializing in the production, research and development and sales of plastic screen printing ink, pad printing ink, toy paint/plastic paint, offset printing ink and various environmentally friendly water-based PU inks.

Jiasheng Ink was established in 1996, with a factory area of 8,000 square meters and 50 employees. After more than 20 years of efforts, we have excellent manufacturing technology, excellent engineering and technical personnel, advanced production equipment and perfect testing equipment. Strong technical force and strict quality inspection. The company's business continues to develop. At present, there are branches in Hunan, Hong Kong, Vietnam, Cambodia and other places, and the distribution shops are all over the country, and the ink is exported to Bangladesh, Cambodia, the Philippines and other places. Strictly implement ISO900 1:2008: 2008 quality management system standards in operation. Ensure that all ex-factory products comply with EN-7 1-3, ROHS ASTM F963, PAHS,

Phthalates, Reach and other international test standards. Our factory has won the trust of our customers with strict management, excellent quality and excellent after-sales service. The company always adheres to the business philosophy of "honesty and prosperity" and always puts quality, service and innovation in a prominent position. Strive for Excellence to make products, create services in a down-to-earth manner, and strive for innovation wholeheartedly. At the same time, the company sincerely looks forward to your joining and working with you to create and grow together!

Consult WeChat/Tel:/kloc-0 18688633953 Contact: Li Renfang