Talking about the difference between dilute agent and white ink

In the formulation of offset printing inks, white ink and diluting agents are often used. However, the white ink and the diluting agent have obvious differences in the use of offset printing because of their different nature. The operator cannot mix the two together; it cannot use the white ink as a diluting agent.

Offset white ink, it has the characteristics of ink.

Diluting agent, as an auxiliary agent for ink, generally refers to Veoli oil, bright light paste, light diffusing agent and the like. They are colorless. In daily printing production, diluting agents are often used together with inks.

White ink and diluting agents are quite different when used in offset printing.

First, the role in the ink

1. The role of white ink: add a little white ink in the color ink, can change the hue of the ink, add the white ink after the ink can make the original ink into a tender, soft jade. Especially in packaging printing products, the designers of printing products are always willing to use white ink to make the printing products produce an elegant and delicate feeling to satisfy people's visual and psychological needs, so as to improve the grade of the packaged products.

2. The role of dilute agent: dilute the agent into the color ink, can change the depth of the ink. In order to meet different levels of color needs, people have different shades of ink by changing the proportion of diluting agent added to the ink. Obviously, the more lightening agent is added, the lighter the ink color is.

Second, in the ink addition and release ratio

Although the white ink and diluting agent play a corresponding role in adding color inks, due to the difference in their respective proportions, they are different in terms of the percentage of ink added.

1. White ink addition and release ratio: White ink is the most heavily used ink in commonly used offset inks. In the offset printing, the ink can reach the surface of the print from the ink fountain, mainly the ink in the ink through the combination with the pigment particles, under the action of the external force "drag" the pigment particles to transfer. In this sense, the oil varnish plays a role of “carrying and transporting” particles. If the granules are heavier, the “carrying capacity” of the dynamizing oil will show an inadequacy and “dragging”. In other words, there is a small amount of pigment particles that stay in place due to the “loading” motionless. Under the effect of the printing plate moisture, the “carry-over” capability of the oil-adjusting oil is further affected. Therefore, when the white ink is used, the heavier ink pigment particles are likely to be partially retained on the surface of the printing plate, so that the printing product produces rough and uneven quality defects. For this reason, under normal circumstances, the proportion of white ink in the color ink is generally not more than 20%.

2. Addition and release ratio of diluting agent: As a diluting agent for diluting the color of ink, due to its lighter weight and better printability, its addition and release ratio in color ink is not limited. According to the shades of the color of the prints, it can be freely added.

Diluents have a better ink transfer rate.

Third, the emulsification problem

1 White ink: Like other inks, the white ink itself has certain anti-emulsification properties. Adding a color ink will not reduce the water resistance of the mixed ink, and the anti-emulsification performance of the mixed ink will not be reduced as a result.

2. Diluter: Due to the composition of the diluting agent itself, its water resistance is relatively weak. Therefore, when the diluting agent is used to adjust the ink, the water resistance of the mixed ink is then decreased, that is, the ink is liable to emulsify. The greater the proportion of the diluting agent added to the ink, the easier it is to produce emulsification, which should be noted.

Fourth, printing process

Because of the difference in specific gravity and water resistance of white ink and diluting agent, their process processing is also different in printing.

1. White ink: After the white ink is added to the color ink in an appropriate proportion, it will not cause great changes in the printing process.

If the amount of white ink is too high, there will be too much pigment particles deposited on the surface of the printing plate. Therefore, in the printing process, the plate must be frequently cleaned with gasoline to ensure that the imprinting is uniform.

2. Diluting agent: Due to poor anti-emulsification ability of the diluting agent, it is necessary to pay attention to the following problems when using a light-colored ink containing a diluting agent.

a. Easily emulsified ink and printing plate adhesion is poor, in the erosion of water, the plate is easy to produce "chemical version" phenomenon, so when printing must maintain a certain amount of ink to prevent "chemical "The phenomenon occurs.

b. Easily emulsifiable ink means that the water is easy to enter the internal structure of the ink. Such ink is printed on the paper so that the print is not easy to dry and is liable to produce a dirty phenomenon of the printed product. Therefore, a corresponding prevention must be taken in the printing process. Dirty measures.

C. Easily emulsifiable inks are not easy to produce dirty prints or stencils during printing. Therefore, it is better to keep smaller prints in printing so that the prints can produce better printing results, and smaller prints can be effective. Reduce the degree of emulsification of the ink.

Fifth, post-press reaction

Compared to products printed with inks containing white ink and those printed with inks containing diluting agents, the color change of their respective prints after a certain period of time is different.

1. White ink's post-press reaction: white ink is not easy to fade, but white ink will appear yellow under the effect of light and water in the air. Obviously, when the white ink is transferred to the paper in the color ink, this phenomenon will also be displayed. The original, bright, imprinted, will also appear yellow after a period of time.

2. Postpress reaction of diluting agent: The diluting agent is colorless. When the diluting agent is combined with the color ink to become a light-colored ink, it gives a vivid impression when it is printed on the paper, but after a period of time when the ink is absorbed by the paper, the “thick” condition of the printed product will change, and the original The imprinting will shift to dryness and darkness, affecting the color effect of printed products. This change is particularly noticeable when printing on rough-surfaced paper.

Sixth, the problem of independent use

White ink: White ink has a certain hiding power. In view of the use properties of the aforementioned white inks, they are generally not used alone.

Diluter: Diluent does not have hiding power. It can be printed separately to meet the special needs of printed products. If the printed product has the need of moisture-proof and ink-repelling layer dropping, the diluting agent can be printed in the last color sequence, and the colorless diluting agent film “seals” the ink and ink layer so that the moisture in the air is not easy to enter the ink layer. And the inside of the paper has a moisture-proof effect and the printed product (such as a cigarette case) is not easy to fall off when the hand is rubbed. At the same time, the use of a diluting agent alone in the final color sequence can change the surface flatness of the printed ink layer to change the reflection state of the light, so that the ink layer of the print appears brighter and deeper.