-UV Flexo inks, the wash up solutions as well as the curing units are unsafe.
UV ink is a 100% solid ink meaning they are virtually free of VOC's. In the past, the inks were made with certain ingredients that acted as a skin and inhalation irritant, which is no longer the case. UV inks should be used with the normal amount of care that would be used for any ink product.
The chemicals used for wash up of the press and work area are on par with other industrial chemicals. Proper care should used when handling any industrial chemicals; UV specific chemistry is no different. That being said, there are many new low VOC products on the market which are both effective and address safety concerns.
The UV curing lamps produce UV energy, visible light and heat. The surfaces of the lamp housing are usually cooled and are generally safe. Ozone is produced by the lamp but is highly radical and quickly dissipates. When properly exhausted there is no health risk.
-UV Flexo inks are too expensive…
While UV flexo inks are generally of higher cost than their conventional counterparts, the energy curable products will provide more mileage. Energy curable ink products usually come up to color quicker than conventional inks, can be left in the press overnight or over the weekend thus producing less waste, saving the printer money and time. Because energy curable inks and coatings “dry” right away, printing presses can usually be run at higher speeds
-UV curing equipment is too costly…
Most new printing equipment can be ordered with OEM UV curing units, lowering the cost. Even with a retrofit, the benefits described in the last response can usually see a ROI in a relatively short period of time.
-The benefits of UV Flexo simply don’t outweigh these negatives…
Each printer and each application will be the judge of the viability of energy curing.. The greatest testament to the positive aspects of energy curing is that it is an established performer that enhances flexibility and quality of the printed good. Energy curing is a positive because it increases productivity of the manufacturing process. From an environmental, production and performance level, energy curing brings money to the bottom line.
-What sort of anilox rollers should I use…
Laser engraved ceramic is the best. Doctor blades should be stainless; a heavier gauge usually works better. NOTE: Because some UV inks are heavier in body than their conventional counterparts, increased microscopic turbulence with a 60 degree cell placement pattern can be greatly reduced by using a 30 degree design.
-Do I need to use special UV specific plate material?
Yes, you must use a photo polymer plate material that is compatible with UV inks.
-Is there any resources to go for non-biased, technical information?
There is a wealth of information available at www.radtech.org, you will find cost comparisons, health and safety issues and a variety of other useful information.
-What is the history of UV inks?
Radiation curing is a broad classification which generally encompasses the use of ultra-violet and electron beam energy as the drying mechanism for inks and coatings. The idea for UV curing inks and coatings is not new. It is an offshoot of research done during WW2 that led to the invention of radar and sonar. The relationship is the fact that UV is a form of wave energy that exists just below the spectrum of visible light.
UV as an energy source for curing ink and coatings was seriously explored during the 1950’s. After more than a decade of research the first commercial run of UV inks took place in 1969. Now, after decades of relatively slow, sporadic growth, the last several years have shown tremendous growth of interest and use of UV inks and coatings.
-How do UV inks and coatings dry?
Simply the process is a photochemical reaction. Ultraviolet light is absorbed and transferred through the ink or coating film. This energy causes the instantaneous formation of radicals that seek out places to bond (radicals are molecules with the ability to join other available molecules). The process is commonly called crosslinking. When crosslinking is caused by UV energy, this process is called polymerization.
-What is the “vehicle” component of UV inks?
In conventional and UV systems the function of the vehicle is the same. It provides a medium in which to disperse and encapsulate the pigment, carry it to the substrate via the printing press, and bind it there.
-What is the “resin” component of UV inks?
The resin is the backbone of the ink system and to that extent imparts the largest contribution to the properties of the wet ink as well as the cured ink film. Most often, inks manufactured for offset or letterpress presses are generally made from one or a combination of the following three types of acrylate: 1) epoxy acrylate, 2) urethane acrylate, 3) polyester acrylate.
Epoxy acrylates are known for their rapid cure response and excellent film hardness. Urethane acrylates are a very good at pigment wetting and are hydrophobic making them an excellent choice for lithography. Polyester acrylates have a broad range of properties making them an excellent modifier for the epoxy resins or as the backbone of the vehicle itself. These resins are commonly referred to as “free radical” systems.
Another group of resins within the family of acrylates centers around cationic curing. Cationics transfer electrons to form acid radicals which facilitate polymerization. These systems are characterized by a very low degree of film shrinkage making them an excellent choice for systems designed to print on “difficult” substrates.
UV ink is a 100% solid ink meaning they are virtually free of VOC's. In the past, the inks were made with certain ingredients that acted as a skin and inhalation irritant, which is no longer the case. UV inks should be used with the normal amount of care that would be used for any ink product.
The chemicals used for wash up of the press and work area are on par with other industrial chemicals. Proper care should used when handling any industrial chemicals; UV specific chemistry is no different. That being said, there are many new low VOC products on the market which are both effective and address safety concerns.
The UV curing lamps produce UV energy, visible light and heat. The surfaces of the lamp housing are usually cooled and are generally safe. Ozone is produced by the lamp but is highly radical and quickly dissipates. When properly exhausted there is no health risk.
-UV Flexo inks are too expensive…
While UV flexo inks are generally of higher cost than their conventional counterparts, the energy curable products will provide more mileage. Energy curable ink products usually come up to color quicker than conventional inks, can be left in the press overnight or over the weekend thus producing less waste, saving the printer money and time. Because energy curable inks and coatings “dry” right away, printing presses can usually be run at higher speeds
-UV curing equipment is too costly…
Most new printing equipment can be ordered with OEM UV curing units, lowering the cost. Even with a retrofit, the benefits described in the last response can usually see a ROI in a relatively short period of time.
-The benefits of UV Flexo simply don’t outweigh these negatives…
Each printer and each application will be the judge of the viability of energy curing.. The greatest testament to the positive aspects of energy curing is that it is an established performer that enhances flexibility and quality of the printed good. Energy curing is a positive because it increases productivity of the manufacturing process. From an environmental, production and performance level, energy curing brings money to the bottom line.
-What sort of anilox rollers should I use…
Laser engraved ceramic is the best. Doctor blades should be stainless; a heavier gauge usually works better. NOTE: Because some UV inks are heavier in body than their conventional counterparts, increased microscopic turbulence with a 60 degree cell placement pattern can be greatly reduced by using a 30 degree design.
| Linecount | Cell Volume | Typical application |
| 85-250 | 12-35 | Adhesives, coatings & porous substrates |
| 300-480 | 5-10 | General purpose, solids |
| 500-800 | 1-6 | Process Work |
| 800-1500 | 1-3 | Fine process work, 150-100 line screen |
-Do I need to use special UV specific plate material?
Yes, you must use a photo polymer plate material that is compatible with UV inks.
-Is there any resources to go for non-biased, technical information?
There is a wealth of information available at www.radtech.org, you will find cost comparisons, health and safety issues and a variety of other useful information.
-What is the history of UV inks?
Radiation curing is a broad classification which generally encompasses the use of ultra-violet and electron beam energy as the drying mechanism for inks and coatings. The idea for UV curing inks and coatings is not new. It is an offshoot of research done during WW2 that led to the invention of radar and sonar. The relationship is the fact that UV is a form of wave energy that exists just below the spectrum of visible light.
UV as an energy source for curing ink and coatings was seriously explored during the 1950’s. After more than a decade of research the first commercial run of UV inks took place in 1969. Now, after decades of relatively slow, sporadic growth, the last several years have shown tremendous growth of interest and use of UV inks and coatings.
-How do UV inks and coatings dry?
Simply the process is a photochemical reaction. Ultraviolet light is absorbed and transferred through the ink or coating film. This energy causes the instantaneous formation of radicals that seek out places to bond (radicals are molecules with the ability to join other available molecules). The process is commonly called crosslinking. When crosslinking is caused by UV energy, this process is called polymerization.
-What is the “vehicle” component of UV inks?
In conventional and UV systems the function of the vehicle is the same. It provides a medium in which to disperse and encapsulate the pigment, carry it to the substrate via the printing press, and bind it there.
-What is the “resin” component of UV inks?
The resin is the backbone of the ink system and to that extent imparts the largest contribution to the properties of the wet ink as well as the cured ink film. Most often, inks manufactured for offset or letterpress presses are generally made from one or a combination of the following three types of acrylate: 1) epoxy acrylate, 2) urethane acrylate, 3) polyester acrylate.
Epoxy acrylates are known for their rapid cure response and excellent film hardness. Urethane acrylates are a very good at pigment wetting and are hydrophobic making them an excellent choice for lithography. Polyester acrylates have a broad range of properties making them an excellent modifier for the epoxy resins or as the backbone of the vehicle itself. These resins are commonly referred to as “free radical” systems.
Another group of resins within the family of acrylates centers around cationic curing. Cationics transfer electrons to form acid radicals which facilitate polymerization. These systems are characterized by a very low degree of film shrinkage making them an excellent choice for systems designed to print on “difficult” substrates.
