Classification of screen printing ink

(1) according to the substrate classification

According to the chemical name of the substrate can be divided into: polyethylene, polypropylene (non-polar) ink. Polyvinyl chloride, polystyrene, ABS polycarbonate (polar) ink. According to the form of substrate can be divided into soft plastic ink and hard plastic ink.

(2) Classification by drying method

Volatile drying ink, UV curing ink, oxidation drying ink.

Volatile drying ink: screen printing is the most used in a kind of ink. The composition of ink film is mainly polymer material, after printing solvent volatilizes, the polymer material will form ink film. This volatile drying process is reversible, that is, the dry ink film can be used to dissolve again.

Ink transfer to substrate, there will be solvent ink film, the first solvent volatilization. The solvent in the ink due to the effect of vapor pressure diffusion in the atmosphere, forming a liquid film on the surface of the ink film, and then through the liquid film volatilization. In this drying process, the internal drying is generally slow, sometimes need to speed up the drying process.

Volatile ink, easy to use, drying generally faster, so it is widely used.

(2) UV curing ink (UV ink) : UV ink can produce photochemical reaction, in a very short few seconds, can be completely cured, used in plastic printing more and more. Ink is the main component of photopolymerization resin, initiator, color and additives, in principle will not use organic solvents.

(3) oxidation drying ink: ink containing polymers with small molecular weight, oxidation in the air, through the chemical reaction of heat, light or reactive substances and the formation of polymer film. This ink in printing to the substrate surface, the general need to promote hardening.

Plastic screen printing ink must have the conditions

(1) Ink on the plate should not dry conjunctiva, and when printing to the substrate surface requirements can be quickly fixed dry, and have a good fastness to adhesion.

The ink should have the characteristics of loose, short, thin and slippery, to ensure that the ink on the plate is easy to spread evenly. It is easy to cross the net under the condition of small force. Printing requirements are clear, no sticky phenomenon.

(3) ink on the plate coating, ink viscosity, viscosity, consistency should have a certain stability, in order to ensure the consistency of printing quality and smooth printing.

(4) after printing, the ink on the plate should be easy to clean, to ensure that the plate can be reused.

⑤ to ensure that printing has a certain color concentration. For colored patterns, make sure they have normal tones.

Suzhou screen printing ink plastic screen printing ink main components

(1) pigment

Including pigments and dyes. Pigment in ink in addition to color function, but also make the ink has hiding power. In addition to the ink light resistance, heat resistance, solvent resistance, drug resistance also have an impact.

(2) the link

Binders are fluid components of ink. It plays a link role, so that color, filler and other solid materials dispersed in which, printing is conducive to the uniform transfer of ink. It is another important role, is to make the ink on the substrate surface dry, fixed and film.

Linker is the key factor to determine the performance of ink, different types of ink, usually choose different properties of linker. Binders include resins, oils, solvents, etc.

(3) additives

Additives is to improve the printing ink of various printing suitability and add a variety of auxiliary agents, mainly antifoaming agent, thinner, plasticizer, ultraviolet absorbent, drying regulator, etc.. Printing is usually done by adding.

Waterborne high temperature resistant silk screen printing ink

Characteristics of water-based high temperature resistant screen printing ink:

Water-based high temperature resistant silk screen printing ink has non-toxic, tasteless, no organic solvent volatiles, low cost, broad material sources, good luster, resistance to weathering, heat resistance, wear resistance and water washing resistance, economic health and other characteristics.

Water-based high temperature resistant screen printing ink according to the use of products, can be divided into: high gloss, ordinary gloss, matt and other three. From the screen process can be divided into: manual screen printing and rotary screen printing two categories. Water-based screen printing high temperature resistant ink in the use process, can eliminate the harm to human body and environmental pollution, has begun to be food, artificial leather, bags and other packaging printing enterprises pay attention to.

In addition to environmental protection, screen printing ink with high temperature resistance compared with solvent based screen printing ink also has the following advantages:

1. Strong wear resistance. Packaging printing accessories need strong wear resistance, determined by 50 pressure per square centimeter, generally should reach 150 rub per minute; Brightness is average, can reach 50 ~ 70 brightness units. Therefore, the packaging screen printing products should not only wear resistance, resistance to 30 points. Clock washing, and up to 121℃ ~ 150℃(3 seconds ~ 10 seconds) can meet this requirement.

2. Fast film forming and drying after printing. The drying process of water-based high temperature resistant silk screen printing ink is 60% by evaporation or volatilization, 40% by material infiltration absorption, drying quickly, about a few minutes or tens of minutes to complete the graphic conjunctiva of the printing ink. If using infrared or hot air drying method can promote the film drying.

3. Convenient use and storage, safe, conducive to safe production and improve the operating staff's working conditions. Because solvent-based or oil-based screen printing ink belongs to the category of dangerous goods, transportation, storage, use is quite inconvenient. The environmental protection type high temperature resistant water screen printing ink with water as the solvent, without any danger, safe and reliable use, water cleaning equipment and cleaning fingers.

Toning methods

Alleged match color is the color of two kinds of above, or it is to use a few colour adjoin again besides advocate tone color colour, form colorific combination. Color ink before the use of deployment, the first color sample on the need to prepare the color alone, the correct identification of the original (or original) color is primary, intermediate, or complex color. If it is indirect color, complex color, need to distinguish the main color and the proportion of the auxiliary color. Secondly, it must be adjusted according to the tone indicated by the original manuscript. When the color difference is smaller or equal to that of the original manuscript, it can be deployed in large numbers, and the time should be short and the amount of adjustment should be appropriate. Too little, resulting in shutdown, ink hue, affect the normal production; Too much leads to unnecessary waste. Toning is usually done in places where the light is stable or not directly illuminated.

Matters needing attention

A. With ink should be as little as possible to add different colors of ink, the less the type of ink, the better the mixing effect. B. Adopt the principle of "from light to deep", regardless of preparation of light or bright color ink, when the hue is close to the sample, be careful. Ink produced by different manufacturers, do not mix call, try to use the same manufacturer of different colors of ink toning, otherwise it will produce the phenomenon of uneven tone, serious cohesion and ink scrap.

C. Some screen printing ink is dried by drying, light drying than not dry shallower, dark drying after deep. In addition, the color of the ink in printing before and after drying whether there is a difference, is easy to ignore the problem. Generally speaking, through the natural drying (solvent volatile ink), substrate is plastic, metal, paper, glass, etc., color will not change; But if the ceramic color, because in the burning oxidation after color, only by experience to color. And through the heat solid, light solid to dry the screen printing ink, color changes in depth, has been mentioned above. When the amount of toning is large, you can use the toning machine to complete the toning in a short time.

Screen printing ink preservation and use period

A. Silkscreen printing ink should be stored in a cool and dry place. If it is UV ink after opening the can, it must be placed in the refrigerator and avoid lighting! Suzhou silk screen printing ink

B. Unopened ink shelf life in 12 months, as soon as possible after opening the can, in principle, not more than 6 months!

C. Different brands of different series of ink can not be mixed