What is UV curing? What is the principle of UV curing?

It seems that someone has asked this question before:

1.A treatment method for curing a coating or binder.

2.Liquids can be converted into solids in a fraction of a second.

The light-curing process is a chemical reaction initiated by UV light.

There are no solvents in the cured material.

It's easier to understand that way.

UV is an abbreviation for Ultra-Violet Ray.

UV lamp: A lamp that emits ultraviolet light.

UV coatings: The main ingredients are 'reactive diluents, oligomers, photoinitiators, additives' (UV glues, UV inks, UV varnishes).

After the UV coating is irradiated by the UV lamp, it produces reactions such as radiation polymerization, radiation cross-linking and radiation bonding. The chemical process of rapidly converting a low molecular weight substance into a high molecular weight product, curing is carried out directly on an unheated substrate, the system contains no solvent or a very small amount of solvent, and the liquid film is almost 100% cured after irradiation, so the VOC (volatile organic compound) emissions are very low. UV light-curing systems are divided into free radical systems and cationic systems, and the curing mechanism components of both are different.

The free radical system is a photoinitiator excited by UV irradiation to produce free radicals, which initiate the polymerization and crosslinking of monomers and prepolymers. The cationic system is made of a cationic photoinitiator that is irradiated to produce strong protic acid, which catalyzes addition polymerization and solidifies the resin. UV radical curing goes through the following steps:

Free radical photoinitiators are irradiated by UV and decompose to produce free radicals

Chain initiation: The free radicals produced by the initiator initiate the unsaturated double bonds of the resin and monomer molecules to produce new free radicals.

Chain growth: The free radicals produced by the resin and monomer can continue to trigger the unsaturated double bonds in the resin and monomer molecules to produce free radicals, which carry out a free radical chain reaction.

Chain termination: In the chemical reaction, because the free radicals contain uncoupled electrons, they are very active, and they are very prone to the coupling or acidification of the radicals, so that the chain reaction is terminated. As a result of the reaction, a polymer compound is formed, which transforms the glue into a solid.

The curing principle is as follows:

1. The characteristics of the cured materialThe efficiency of a UV lamp is determined by the difficulty of emitting photons into the curable material to activate the light-triggerable molecules.

2. UV curing is determined by the collision of photons and molecules, and light can trigger molecules to diffuse uniformly through the material, but photons are different.

3. In addition to the characteristics of the UV light source, the cured film or the worm also has optical and thermodynamic properties, which interact with the radiation energy and have a significant impact on the curing process.

4. The spectral absorption rate energy is the effect of the wavelength absorbed by the substance in the gradually increasing thickness, and the more energy absorbed near the surface, the less energy is obtained in the deep layer.

Each has its own advantages and disadvantages.

UVLED light curing has low energy consumption and fast speed, and the disadvantage is that the opaque area of the shadow cannot be cured.

The applicability of thermal curing is easy to sell, but the curing speed is slow, the energy consumption is high, and the process source is also complex.

Light curing and thermal curing, UVLED light curing, shed leakage and thermal curing, as the current mainstream curing methods of Lianghuna, are often compared. The two curing methods have their own advantages and disadvantages, and it is not possible to generalize which method is better.

The curing mechanism of UV paint is as follows: Deep curing is often considered in the application of light-curing coatings, which is due to the attenuation of the intensity of light as it passes through the absorbing substance. The degree to which the photodefeat finger solidifies can be described by Beer-Lambert's law:

l=l0*10- cl lgl0 l= cl where l0 is the intensity of the incident light;l is the intensity of the projected light;The extinction coefficient for molchasan is related to the nature of the light-absorbing substance in the penetrated substance and the wavelength of the incident lightc is that the greater the concentration of the absorbent substance, the more serious the light weakening, so the excessive concentration of photoinitiator in practical application is not conducive to deep curing.

Through the above analysis, it can be seen that when UV paint is cured, the intensity of the UVLED curing machine will be attenuated due to different irradiation distances, resulting in a huge difference in absorbed energy, resulting in uneven curing of the paint film.

The chemical bond of UV paint can absorb a certain range of wavelength of light, so that a chemical reaction occurs, and the original liquid oil excitation paint becomes solid with jujube socks. Hope.

Air oxidation solidification.

Air balance oxidation solidification is to use the oxygen in the air to dry the paint into a film, and the oxygen in the air cross-reacts with the paint to form a dry coating film.

2. Solvent volatilization and curing.

Solvent volatilization solidification means that the solvent volatilizes through the surface of the coating, leaving the solid matter of the coating and being attached to the surface of the coated object, forming a solid coating film with dry cores.

3 Thermal reaction or chemical reaction curing.

This type of coating produces a chemical cross-linking reaction under the action of heat or under the action of a catalyst (including assimilants), and various components in the coating.

The film components are fused with each other and cross-linked to form a three-dimensional network structure of the coating film. This type of coating will no longer be dissolved by solvents or softened by heat after curing, and its physical and chemical properties are better than those of solvent volatile coatings.

4 Radiation curing.

Radiation-curing coatings refer to two types: ultraviolet curing and electron-curing.

5 Melt curing.

Melt-cured coatings generally refer to solid powder type coating products.

6. Infrared-catalyzed thermal reaction curing.

Infrared-catalyzed thermal reaction curing is a kind of bridging that uses the infrared energy absorbed by the coating itself to convert it into heat energy to solidify the coating film.

LED UV curing machine is the English abbreviation of LED ultraviolet, curing refers to the process of transforming a substance from low molecule to high molecule. UV curing generally requires the curing conditions or requirements of ultraviolet curing coatings (paints), adhesives (glues) or other potting sealants, which are different from heating curing, adhesive (curing agent) curing, natural curing, etc.

Using UV1610 printer, LED lights are used, which are hit and dried when printing, so it is called LED-UV curing technology.

LED-UV curing technology is a new type of UV curing, which replaces the traditional mercury lamp UV curing, LED UV curing has the advantages of high efficiency, energy saving, environmental protection, low temperature and long life. It is mainly composed of three parts: LED UV light source, drive control and cooler.

LED UV light source: emits ultraviolet light and cures UV coatings. It is best to choose vacuum inorganic material packaging for the light source, which has less light decay and better stability.

Drive control: control the brightness and darkness of the light source, equipped with an abnormal monitoring system, equipment online signal, can be set to cure, the product will be bright after passing, and it will not be bright if there is no product flowing.

There are air cooling and water cooling methods, and the temperature of the water cooling LED will be lower, so that the service life of the UV LED will be longer.

UV curing is mainly used to guess the following raw materials:

UV photoinitiator: A chemical substance that absorbs UV light and produces free radicals or ions, which trigger a light-curing reaction.

Resin: A resin is a polymer that reacts with UV photoinitiators and forms a solid structure. Common resins include acrylic resin, epoxy resin, etc.

Light thinner: is an auxiliary material that can reduce the viscosity of the resin for easier coating and printing. At the same time, the light diluent can also reduce the absorption of UV light, which promotes the penetration of light through the resin layer, resulting in a better light-curing effect.

Additives: In order to improve the performance of UV light-curing products, various additives can be added, such as anti-yellowing agents, plasticizers, weather resistant agents, fillers, etc.

Substrates: The substrates of UV light-curable materials can be a variety of different materials, such as paper, plastic, metal, glass, etc.

UV curing machine is a widely used equipment;

UV itself is the meaning of ultraviolet rays, and the field of ultraviolet light curing used in sliding code industry can be roughly divided into several categories:

Printing industry: 2The plastic industry did not let it leak;

3.Electronics industry.

4.Lighting industry.

5.Automotive industry.

6.Arts and crafts industry.

7.Glass withered glass industry.