Compositional Characteristics and UV Printing of UV Ink

The composition of the UV ink is mainly composed of a pigment, an Olymmer, a monomer, a photoinitiator sensitizer, and a filler, etc. The compositional differences of the oxidized inks are shown in Table 5.

From Table 5, it can be clearly seen that the corresponding component functions between the UV ink and the traditional ink are similar, and the chemical composition is completely different.

UV ink characteristics:

The characteristics of UV inks can be summed up in the following 12 points:

1. No need to spray powder

2. Immediately dry, but need to use ultraviolet light to dry

3. No UV light is not skinned, so it is not crusted in the ink tank

4. Ink does not contain solvents

5. Printable non-absorbent printed material

6. Ink film is uniform and has better friction resistance

7. It will not dry on the printer or on the plate before it is irradiated.

8. It will change under high temperature and high humidity and should be kept below 20°C

9. Cannot be mixed with general ink

10. Thinners and cleaning agents must be used exclusively by UV. Inkers and blankets must also be used exclusively or concurrently.

11. UV inks are not universal for all materials and their adhesion depends on the nature of the ink. Individual tests

12.UV is a chemical line. The wavelength required for ink drying must be close to the UV wavelength, otherwise drying efficiency cannot be achieved.

Discussion on UV Printing

(I) Factors affecting the drying of UV inks

The length of UV ink drying time is generally affected by the following factors:

1.UV ink thickness

2. Different types of printed materials

3. The speed of the machine

4.UV Reflector Type

5.UV lamp strength

(b) Materials commonly used in UV printing

The materials used for UV printing are usually non-absorbent materials. In addition to paper, plastic materials and metals are commonly used. In this article, only plastic materials are introduced.

The nature of plastics is mainly determined by the size and shape of its constituent molecules. Most plastics are monolithic in the first few stages of manufacture, that is, they consist of small units of molecules, but they function in heat, pressure, and chemical catalysts. Next, these small molecules combine into complex molecules and become solid or semi-solid structures. The plastic properties can be listed as follows:

1. Resistant to chemical attack

2. Glossy, partially transparent or translucent

3. Most plastics are good insulators

4. Lightweight, but strong, and can even replace metal

5. Large-scale production, easy processing, and low price

6. Widely used, effective and colorful

7. Physical stability, good electrical properties

8. Flexible, easy to color, some high temperature

Because plastics have many of the above advantages, new plastics have also been continuously researched and developed, with various properties such as engineering plastics or polymer plastics. High-molecular polymers are high-molecular-weight compounds that contain a covalent bond as a binding atom or a binding force between molecules. In general, a molecular weight of 1,000 or more can be referred to as a polymer. In nature, natural rubber, protein, cellulose, starch, and asbestos are all high molecular substances.

The polymer is formed by the bonding of monomers. Usually, the structural unit is used to describe the structure of the polymer, and the structural units have different arrangement and connection methods, such as a linear polymer, whose structural units are The arrangement on the chain is X -(M)n -Y, where M is a structural unit, ie, a monomer, and n is a degree of polymerization, abbreviated as dp. When n is 2, they are called dimers. When n is 3, they are called trimers. When n is 4, they are called tetramers. The number of n can reach as many as 10 million. About two ends of a structural unit M are linked by X and Y, and X and Y may be the same or different. Polymers that contain the same repeating units are called homopolymers, such as polyethylene. Polymers containing two or more structural units, called copolymers. The polymerization forms include addition polymerization, condensation polymerization and combination polymerization.

Author: Zhang Line Source: Graphic Arts 256 (April 2005)