UV curing is called UV Curing or UV Coating in English. UV curing is a photochemical reaction. UV coating is applied to the surface of the crystal and is cured by UV radiation. UV curing is similar to the traditional drying process, but the principle is different. Traditional Drying is generally hardened by the volatilization of the solvent in the coating material, whereas UV curing is solvent free evaporation.
Photoinitiators (or photosensitizers) are added to specially formulated resins to produce reactive free radicals or ionic groups after absorption of high-intensity ultraviolet light in ultraviolet (UV) light curing equipment, thereby initiating polymerization, cross-linking, and grafting The reaction causes the resin (UV coating, ink, adhesive, etc.) to be converted from a liquid state to a solid state within seconds (unequal). (This process is called "UV curing")
UV lamp
On the short wavelength side of visible light, there is an ultraviolet (abbreviated as UV) region, and the wavelength range is 100 to 400 nm. The ultraviolet region can be divided into the following wavelength domains according to the International Commission on Illumination (CIE) and the International Electrotechnical Commission (IEC):
UV-A: 315~400nm
UV-B: 280~315nm
UV-C: 100~280nm
UV-V: 390 nm or more
(The UV-C wavelength range has not been unified in biology, hospitals, chemistry, etc.)
According to the photon energy E=h/λ (h constant, λ light wavelength), the shorter the wavelength, the higher the photon energy. The lower energy UV-A has a photochemical effect, so it is also called a chemical line. UV-A is used in the fields of organic synthesis, UV curing of adhesives or adhesives. UV-B has a large effect on living organisms and can cause erythema and pigmentation. Therefore, it is also called a biological line. UV-C is far ultraviolet rays. Because of its short wavelength and high energy, it has a bactericidal effect and can decompose the binding of molecules. For the UV glue curing, only UV-A has a strong effect. Ultraviolet UV-curable glue can quickly cure under the ultraviolet light with the wavelength of 365nm-400nm, so as to exert the required strength.
The UV curing device consists of a light source system, a ventilation system (fan), a control system (digital display timer), and a cabinet.
UV light source system
It consists of a UV lamp, a lamp shade, a transformer (ballast), and a capacitor (trigger).
1. UV tube
At present, UV lamps on the market are divided into two types: high-pressure mercury lamps and metal halide lamps. High-pressure mercury lamps are commonly used in domestic equipment, and some of the imported equipment use metal halide lamps. (metal halide lamp recommended)
(1) UV lamp power selection. The power of a UV lamp, that is, the radiant energy of a UV lamp, is also called penetrating power. First, it must meet the spectral wavelength and power density requirements of UV ink (gloss) absorption. If the power of the UV lamp is not enough, even if the lighting time is longer, the number of UV curing devices is more, and the product cannot reach full curing. On the contrary, the surface of the UV ink (gloss) will be aged, closed, brittle, and the like. At the same time, the adhesion of the ink (bright oil) is also not good, and the superimposed interlayer adhesion force will be poor. Because the low-power UV light cannot penetrate the bottom of the ink layer, the bottom is not cured or cured sufficiently.
2, UV lamp power generally meet the requirements of 80 ~ 120W/cm, but the greater the power will be the greater the heat, so depending on the curing and curing speed to choose different power.
The intensity of the UV lamp The intensity of the UV lamp depends on the power density of the UV lamp. Common specifications are:
80W/cm is 200W/inch 120W/cm ie 300W/inch
160W/cm is 400W/inch
240W/cm is 600W/inch
(3) The maximum lifetime of a UV lamp (high-pressure mercury lamp) is generally 800-1000 hours, and it should be replaced after it is reached, because the intensity of ultraviolet rays emitted by the UV lamp at this time becomes weak, which will affect the curing effect. At the same time, according to the different production environments (dust content of air) during the service period, it is recommended to clean the reflection plate on the surface of the lamp tube and reflector surface with absolute ethanol at an appropriate time, and then turn the UV lamp tube by 90°. This facilitates the effective radiation of UV rays to UV inks or varnish. .
Reflector
The types of reflectors are focused, non-focused, and multi-faceted reflective. The focus is generally used. The structure of this reflector is characterized by the concentrated energy of the reflected UV light, the high efficiency of photo-curing, which is conducive to the solidification of the ink of the thick ink layer, and the complete curing of the deep ink layer.
3. Transformer
The choice of transformer must match the power of the UV lamp, ie the transformer must have sufficient output voltage to ensure that the UV lamp can operate at full power. If the output voltage is too high, the lamp tube will be burnt; and if the output voltage is too low, the lamp tube will not be able to work at full power, so that the intensity of the ultraviolet output will be insufficient.
4. Capacitor
The choice of the capacitor should be matched with the lamp and the transformer, and select the capacity of the capacitor used according to the output voltage of the transformer. If it is not properly selected, the capacitor will breakdown, affecting the normal operation of the UV curing device.
Well, now we understand the main parts, then we start assembling it
To ensure that the UV lamp works properly, the following elements must be guaranteed:
The first choice is the matching point uv lamp power supply, the matching uv transformer/capacitor should be consistent with the voltage/current required by the UV lamp, the uv transformer rated power/secondary voltage/operating current/insulation coefficient/pressure resistance degree and capacitor capacity / Pressure resistance / number of discharges can directly determine the UV lamp's luminous efficiency / stability and life;
The second adapter fan must match the power of the UV lamp. Note: It is not allowed to cool the surface of the lamp with strong wind, otherwise the lamp surface temperature will cause the lamp to extinguish and extinguish the lamp.
The third choice of suitable reflectors: UV lampshades custom lampshades on the market are generally divided into spotlights and parallel light shades.
Photoinitiators (or photosensitizers) are added to specially formulated resins to produce reactive free radicals or ionic groups after absorption of high-intensity ultraviolet light in ultraviolet (UV) light curing equipment, thereby initiating polymerization, cross-linking, and grafting The reaction causes the resin (UV coating, ink, adhesive, etc.) to be converted from a liquid state to a solid state within seconds (unequal). (This process is called "UV curing")
UV lamp
On the short wavelength side of visible light, there is an ultraviolet (abbreviated as UV) region, and the wavelength range is 100 to 400 nm. The ultraviolet region can be divided into the following wavelength domains according to the International Commission on Illumination (CIE) and the International Electrotechnical Commission (IEC):
UV-A: 315~400nm
UV-B: 280~315nm
UV-C: 100~280nm
UV-V: 390 nm or more
(The UV-C wavelength range has not been unified in biology, hospitals, chemistry, etc.)
According to the photon energy E=h/λ (h constant, λ light wavelength), the shorter the wavelength, the higher the photon energy. The lower energy UV-A has a photochemical effect, so it is also called a chemical line. UV-A is used in the fields of organic synthesis, UV curing of adhesives or adhesives. UV-B has a large effect on living organisms and can cause erythema and pigmentation. Therefore, it is also called a biological line. UV-C is far ultraviolet rays. Because of its short wavelength and high energy, it has a bactericidal effect and can decompose the binding of molecules. For the UV glue curing, only UV-A has a strong effect. Ultraviolet UV-curable glue can quickly cure under the ultraviolet light with the wavelength of 365nm-400nm, so as to exert the required strength.
The UV curing device consists of a light source system, a ventilation system (fan), a control system (digital display timer), and a cabinet.
UV light source system
It consists of a UV lamp, a lamp shade, a transformer (ballast), and a capacitor (trigger).
1. UV tube
At present, UV lamps on the market are divided into two types: high-pressure mercury lamps and metal halide lamps. High-pressure mercury lamps are commonly used in domestic equipment, and some of the imported equipment use metal halide lamps. (metal halide lamp recommended)
(1) UV lamp power selection. The power of a UV lamp, that is, the radiant energy of a UV lamp, is also called penetrating power. First, it must meet the spectral wavelength and power density requirements of UV ink (gloss) absorption. If the power of the UV lamp is not enough, even if the lighting time is longer, the number of UV curing devices is more, and the product cannot reach full curing. On the contrary, the surface of the UV ink (gloss) will be aged, closed, brittle, and the like. At the same time, the adhesion of the ink (bright oil) is also not good, and the superimposed interlayer adhesion force will be poor. Because the low-power UV light cannot penetrate the bottom of the ink layer, the bottom is not cured or cured sufficiently.
2, UV lamp power generally meet the requirements of 80 ~ 120W/cm, but the greater the power will be the greater the heat, so depending on the curing and curing speed to choose different power.
The intensity of the UV lamp The intensity of the UV lamp depends on the power density of the UV lamp. Common specifications are:
80W/cm is 200W/inch 120W/cm ie 300W/inch
160W/cm is 400W/inch
240W/cm is 600W/inch
(3) The maximum lifetime of a UV lamp (high-pressure mercury lamp) is generally 800-1000 hours, and it should be replaced after it is reached, because the intensity of ultraviolet rays emitted by the UV lamp at this time becomes weak, which will affect the curing effect. At the same time, according to the different production environments (dust content of air) during the service period, it is recommended to clean the reflection plate on the surface of the lamp tube and reflector surface with absolute ethanol at an appropriate time, and then turn the UV lamp tube by 90°. This facilitates the effective radiation of UV rays to UV inks or varnish. .
Reflector
The types of reflectors are focused, non-focused, and multi-faceted reflective. The focus is generally used. The structure of this reflector is characterized by the concentrated energy of the reflected UV light, the high efficiency of photo-curing, which is conducive to the solidification of the ink of the thick ink layer, and the complete curing of the deep ink layer.
3. Transformer
The choice of transformer must match the power of the UV lamp, ie the transformer must have sufficient output voltage to ensure that the UV lamp can operate at full power. If the output voltage is too high, the lamp tube will be burnt; and if the output voltage is too low, the lamp tube will not be able to work at full power, so that the intensity of the ultraviolet output will be insufficient.
4. Capacitor
The choice of the capacitor should be matched with the lamp and the transformer, and select the capacity of the capacitor used according to the output voltage of the transformer. If it is not properly selected, the capacitor will breakdown, affecting the normal operation of the UV curing device.
Well, now we understand the main parts, then we start assembling it
To ensure that the UV lamp works properly, the following elements must be guaranteed:
The first choice is the matching point uv lamp power supply, the matching uv transformer/capacitor should be consistent with the voltage/current required by the UV lamp, the uv transformer rated power/secondary voltage/operating current/insulation coefficient/pressure resistance degree and capacitor capacity / Pressure resistance / number of discharges can directly determine the UV lamp's luminous efficiency / stability and life;
The second adapter fan must match the power of the UV lamp. Note: It is not allowed to cool the surface of the lamp with strong wind, otherwise the lamp surface temperature will cause the lamp to extinguish and extinguish the lamp.
The third choice of suitable reflectors: UV lampshades custom lampshades on the market are generally divided into spotlights and parallel light shades.
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