Water-based inks: environmental solutions for apparel printing

Editor's note: The relentless pursuit of sustainable development has prompted many screen printing companies to change their production methods and their choice of consumables. In the following article, we will explain why water-based inks are ideal for printing special effects on garments and how we can use the latest inks to produce unique printing effects.

Most garment printing companies that buy water-based inks are designed to meet the needs of customers for environmentally-friendly products. It is generally believed that if the ink is soluble in water, it will not use minerals or harmful chemical agents during the cleaning process, and therefore it will not be detrimental to the environment. Some people may say that you have a lot of restrictions when using water-based inks. For example, you can only use a lower number of screens and you cannot print on black T-shirts. As soon as this statement was forthcoming, it immediately caused the printer to panic. You may also have heard that water-based inks dry on the screen. Imagine how suffocating it was when everyone was sultry in the scorching summer afternoon, when the printing screen was blocked and the delivery date was looming. Few people will admit that they enjoy using a water-based ink system, but you should at least keep abreast of the advantages and disadvantages of water-based inks for textile printing.

About water-based inks Most traditional water-based inks contain 60% to 70% of water, which tends to give people a sense of security, causing them to mistake the remaining 30% to 40% of the ink. Solids are simply not enough to challenge local waste disposal and safety disposal regulations. However, in fact, water-based inks need to be treated in exactly the same way as thermosetting inks. All factory inks must be equipped with Material Safety Data Sheets for printing factory inquiries. In addition, because water-based inks also emit VOCs (Volatile Organic Compounds), necessary ventilation must be performed. Since the late 1950s, water-based inks have been used in the field of apparel printing. Although thermosetting inks have opened up a new era of large-scale printing T-shirts, and its share in the market has also increased over time - especially as technology continues to advance - but water-based inks It still has a large number of niche markets and has become a core tool for many printing companies.

One of the main reasons why people choose water-based inks is that they are cheaper than thermosetting inks, and they require less equipment, making them particularly suitable for mass printing of light colored garments. In addition, it is also very convenient for the printing factory to carry out its own production. The printing house can purchase raw materials separately and then mix them in a production workshop. Producing ink yourself is a good way to save money because the life cycle of mixed inks is shorter than that of thermosetting inks. Its feel is very soft and it is easily diluted with water - although it can only be used on white clothes, it also eliminates people's concerns about color fastness and opacity. The traditional problem of water-based inks Opacity has always been a weakness of water-based inks. Since this ink has a low solid content (as low as 30%), it is not possible to obtain a good printing effect on colored, black or striped garments. Since water in the water-based ink evaporates during curing, only a very thin transparent ink film can be formed. As we said before, for white clothing, this is not a big problem, and in order to achieve a particular visual effect, water-based ink can also be used in colored clothing, but dark clothing is usually Do not use this ink. In addition, the drying speed of the ink itself on the screen is very fast, so that it is almost impossible to perform long-time printing production. Although the addition of retarder can play a role, the drying speed of the ink on the screen is still a very difficult problem. The use of dyed undercoat is an effective solution to this problem, but it is not environmentally friendly because of the high formaldehyde content of this material. And the pungent odor of discharging the color makes it very inconvenient to use. Many printing companies even refuse to use this material in the production process. In recent years, people have made great progress in the development of ink discharge. Their formaldehyde content has dropped significantly and the smell has become more fresh. In some new products, the original discharge agent has been replaced by Other sodium-based materials. Although we have made certain breakthroughs in technology, we still hope that the environmental performance of discharging inks will be further improved in the future.

Ink paper manufacturers have been working hard to increase the solids content of water-based inks and hope to increase their possibilities of printing on dark clothing. This trend has been confirmed by facts in the past 10 to 15 years. Although the new water-based ink has significantly improved in opacity and color fastness, it does not increase its own time on the screen. Some water-based inks are even more difficult to manage and dry faster. The choice of ink is still a difficult problem: cheaper inks may be more environmentally friendly, can achieve good printing effects and opacity on dark clothing, and can be diluted in light-colored clothing; but they are very Difficult to adapt to long-term print production. In addition, although we can use retarder to prolong its drying time, it is impossible to solve the problem and many users regard water-based ink as the curse of the printing factory. In recent years, with the continuous deepening of the concept of sustainable development and continuous improvement of end-user environmental awareness, the application of environmental protection ink in the field of screen printing has also made certain progress. With the advent of PVC-free thermosetting inks, water-based inks have once again become the focus of attention. Most ink manufacturers now offer this type of product to customers.

Water-based ink technology has made great progress in recent years. Due to the use of new wetting agents and emulsifiers, the drying of the ink on the screen is effectively mitigated. In addition, some new inks can even stay on the screen four to five times longer than before, and they will not block or dry. Even if the water-based ink loses its moisture under the action of a desiccator or extreme weather, it can be re-emulsified and utilized. At present, the shelf life of water-based inks has been significantly improved, and some products can even be stored for two years under the right circumstances. Water-based inks have now extended their application to the market for thermosetting inks. The white inks that can be used to render dark clothing and the ability to print on high meshes make water-based inks infinite possibilities for users in an unprecedented way. For example, a halftone pattern is printed on a dark garment using the same mesh as the thermosetting ink. In addition, printers can also use the latest development of modifiers and emulsifiers to adjust and manage the drying time of the water-based ink on the screen. The last obstacle that water-based inks currently have to overcome is the use in special effects printing. As we all know, thermosetting inks are widely used in special effects printing. They can not only print high-density, gel-like, leather-like, metallic and thermosetting background colors, but also can be used to achieve various textures and glosses. Degree of text and effects. Many curable and non-curable reducing agents can give thermoset inks softness comparable to water-based inks, but these types of reducing agents often contain PVC, phthalates, heavy metals and some It is a known hazardous substance and therefore has an adverse effect on the environment.

Many of the thermoset inks that are currently sold on the market that do not contain PVC and phthalates cannot be compared to thermosetting inks containing these materials in the printing of professional backgrounds. However, some of the latest water-based inks with higher solids content can expand their application range under the influence of a series of auxiliary additives. Although we are not yet able to print transparent gels with water-based inks, you can create a variety of visual effects by adding metal powders, thickeners, and foaming agents.

The higher solids content of the water-based ink allows the printer to obtain a thicker ink film, which in turn gives the original texture effect. In addition, the user can also reduce the opacity of the water-based ink by adding water to print an ideal washing effect. Remember that some additives contain neither PVC nor phthalates, nor do they contain heavy metals, pesticides, azo dyes, pentachlorophenol, or polychlorinated biphenyls, so from current standards, they are still very environmentally friendly. of.

Continuing to focus on water-based inks The extended shelf life will not only reduce the waste of water-based inks, but also increase their sustainability. All in all, the prospects of water-based inks are still very optimistic. The major trend of protecting the environment has now been verified in various fields of the global economy, and we also hope to see the large-scale application of environmentally friendly screen printing inks as soon as possible. In essence, water-based inks play a very special role in the transformation of the screen printing industry. Although thermoset inks will not be eliminated in a short period of time, water-based environmentally friendly ink products will capture even greater market share - especially in the area of ​​specialty printing.