Shrink ink chemical composition
The coefficient of friction of the ink plays an important role in the application of the sleeve label, which determines the efficiency of the label sliding across the container. There are few inks that are generally suitable for flexographic printing.
Environmentally friendly water-based inks are not only highly elastic, but also have a shrinkage rate of more than 40%. It costs less than UV inks and is less affected by the movement of atoms in chemical molecules. Similar to water inks, solvent inks are also very flexible and shrinkage rates exceed 40%. The drying of a solvent-based ink is also less affected by moisture, but it is affected by the movement of atoms in chemical molecules.
UV radical ink can be instantly cured. This ink is affected by oxygen rather than moisture. Generally, the shrinkage of UV radical ink is less than 20%. On some printing materials, its adhesion is limited. Two types of free radical inks have now been introduced to the market.
1. UV inks use a sensitizer to absorb UV light and start the hard curing process.
2. The electron beam produces polymerization, eliminating the need for photosensitizer.
For most printing materials, UV cationic inks are suitable, and its shrinkage capability can exceed 40%. This ink is also very elastic. In addition, the oiler can be cured almost instantaneously, but the price is much more expensive than the UV radical ink.
Advice on prepress design
For prepress designers who shrink labels, be sure to consider the shape of the container, and try not to place the key image in a highly constricted place. The other is to consider where to place the barcode. Bar codes are generally printed vertically to prevent image distortion and affect scanning.
Many computer programs can interpret distorted images, but in some cases (especially for low-shrinkage applications), distorted images are considered waste.
Knowledge about shrink film
A typical shrink film has a thickness of 50 μm and has been relatively thin in the past few years, with a thickness of approximately 40 μm to 45 μm. The thickness of the film used is determined by the type of label printer. It is generally recommended that label printers purchase some of the more expensive shrink films, which have a higher shrinkage.
Although the shrink film is designed to shrink in a certain direction, there is also a slight contraction in the opposite direction. Since the shrink film is sensitive to heat, extreme care must be taken in the storage, printing, and transportation of the shrink film. Most film manufacturers recommend that the film be stored in an easily controllable environment. The temperature should be maintained at 21°C to 32°C immediately before the label is affixed to the container.
By calculating the minimum contraction rate required for the container, the value obtained is used as a reference for the shrinkage requirements of the film. The shrinkage of the film must not be lower than this value. If the diameter of a container suddenly changes, you must choose a film with a stronger contraction force.
In order to calculate the printing width of the label, two overlapping widths can be added to the maximum width of the container. The sleeve is to be added 4mm, so that the sleeve can slide on the container.
PVC (polyvinyl chloride), now used in the shrink film, 2/3 of PVC shrink film. The reason that PVC is valued in the industry is that its shrinkage capacity is kept at 40%-60%, while its cost is low and its strength is high. It is suitable for multiple-sealing and anti-theft device edge strips.
However, the environmental pollution caused by PVC cannot be ignored. Plastic container recyclers generally do not accept PVC in the recycling process. In particular, they must be separated from PETG (ethylene glycol polyester) containers. Because the proportions of PVC and PETG are close to 1.33, it is difficult to separate the two in the recycling process with today's technology.
PETG (ethylene glycol), which has a high shrinkage of 78%, was previously considered to be a PVC substitute and has a market share of approximately 15%-20%. Now that the PETG market is growing, PVC is regressing. However, due to the high cost of PETG raw materials, it has hindered further development, especially when the newer, more competitive materials are entering the vehicle market.
OPS (Oriented Polystyrene) has become a printing material that many countries in the world like to choose. OPS is more environmentally friendly than PVC and economical than PETG. The OPS's ability to shrink up to 65% is comparable to other high shrinkage films. The proportion of OPS is 1.025, and the profit advantage is 20% higher than PVC and PETG. Another advantage of using OPS is that it shrinks little in the opposite direction and does not even shrink.
Although OPP (Oriented Stretched Polypropylene) is not good in shrinkage, it has a place in the market of wrapping shrink film and its market share reaches 18%-20%. OPP is suitable for containers that require low shrinkage and are near cylindrical. The proportion of OPP is 0.90. The price is competitive, and the output is large, successfully blocking the entry of other printing materials.
Printing on a white OPP surface requires adding something else to stop the friction. OPP is different from the printing materials mentioned earlier. It is designed specifically for wrapping.
Future film
Now, several companies are researching environmentally friendly films that have potential for non-petrochemicals. This film was even tried as a basic material for the container. This material is a PLA (resin) that can be used as a compost and can be decomposed by living things. Due to the rising prices of petrochemical products relied on by industry, PLA printing materials can naturally become another choice. Although this printing material is a bit advanced, it may enter the market faster than expected.
Entering the shrink film market must be timely and take pains. In the long run, market investment should be profitable. However, its important technical problems cannot be solved independently, so your production chain must include printer manufacturers, inks, and material suppliers.
The coefficient of friction of the ink plays an important role in the application of the sleeve label, which determines the efficiency of the label sliding across the container. There are few inks that are generally suitable for flexographic printing.
Environmentally friendly water-based inks are not only highly elastic, but also have a shrinkage rate of more than 40%. It costs less than UV inks and is less affected by the movement of atoms in chemical molecules. Similar to water inks, solvent inks are also very flexible and shrinkage rates exceed 40%. The drying of a solvent-based ink is also less affected by moisture, but it is affected by the movement of atoms in chemical molecules.
UV radical ink can be instantly cured. This ink is affected by oxygen rather than moisture. Generally, the shrinkage of UV radical ink is less than 20%. On some printing materials, its adhesion is limited. Two types of free radical inks have now been introduced to the market.
1. UV inks use a sensitizer to absorb UV light and start the hard curing process.
2. The electron beam produces polymerization, eliminating the need for photosensitizer.
For most printing materials, UV cationic inks are suitable, and its shrinkage capability can exceed 40%. This ink is also very elastic. In addition, the oiler can be cured almost instantaneously, but the price is much more expensive than the UV radical ink.
Advice on prepress design
For prepress designers who shrink labels, be sure to consider the shape of the container, and try not to place the key image in a highly constricted place. The other is to consider where to place the barcode. Bar codes are generally printed vertically to prevent image distortion and affect scanning.
Many computer programs can interpret distorted images, but in some cases (especially for low-shrinkage applications), distorted images are considered waste.
Knowledge about shrink film
A typical shrink film has a thickness of 50 μm and has been relatively thin in the past few years, with a thickness of approximately 40 μm to 45 μm. The thickness of the film used is determined by the type of label printer. It is generally recommended that label printers purchase some of the more expensive shrink films, which have a higher shrinkage.
Although the shrink film is designed to shrink in a certain direction, there is also a slight contraction in the opposite direction. Since the shrink film is sensitive to heat, extreme care must be taken in the storage, printing, and transportation of the shrink film. Most film manufacturers recommend that the film be stored in an easily controllable environment. The temperature should be maintained at 21°C to 32°C immediately before the label is affixed to the container.
By calculating the minimum contraction rate required for the container, the value obtained is used as a reference for the shrinkage requirements of the film. The shrinkage of the film must not be lower than this value. If the diameter of a container suddenly changes, you must choose a film with a stronger contraction force.
In order to calculate the printing width of the label, two overlapping widths can be added to the maximum width of the container. The sleeve is to be added 4mm, so that the sleeve can slide on the container.
PVC (polyvinyl chloride), now used in the shrink film, 2/3 of PVC shrink film. The reason that PVC is valued in the industry is that its shrinkage capacity is kept at 40%-60%, while its cost is low and its strength is high. It is suitable for multiple-sealing and anti-theft device edge strips.
However, the environmental pollution caused by PVC cannot be ignored. Plastic container recyclers generally do not accept PVC in the recycling process. In particular, they must be separated from PETG (ethylene glycol polyester) containers. Because the proportions of PVC and PETG are close to 1.33, it is difficult to separate the two in the recycling process with today's technology.
PETG (ethylene glycol), which has a high shrinkage of 78%, was previously considered to be a PVC substitute and has a market share of approximately 15%-20%. Now that the PETG market is growing, PVC is regressing. However, due to the high cost of PETG raw materials, it has hindered further development, especially when the newer, more competitive materials are entering the vehicle market.
OPS (Oriented Polystyrene) has become a printing material that many countries in the world like to choose. OPS is more environmentally friendly than PVC and economical than PETG. The OPS's ability to shrink up to 65% is comparable to other high shrinkage films. The proportion of OPS is 1.025, and the profit advantage is 20% higher than PVC and PETG. Another advantage of using OPS is that it shrinks little in the opposite direction and does not even shrink.
Although OPP (Oriented Stretched Polypropylene) is not good in shrinkage, it has a place in the market of wrapping shrink film and its market share reaches 18%-20%. OPP is suitable for containers that require low shrinkage and are near cylindrical. The proportion of OPP is 0.90. The price is competitive, and the output is large, successfully blocking the entry of other printing materials.
Printing on a white OPP surface requires adding something else to stop the friction. OPP is different from the printing materials mentioned earlier. It is designed specifically for wrapping.
Future film
Now, several companies are researching environmentally friendly films that have potential for non-petrochemicals. This film was even tried as a basic material for the container. This material is a PLA (resin) that can be used as a compost and can be decomposed by living things. Due to the rising prices of petrochemical products relied on by industry, PLA printing materials can naturally become another choice. Although this printing material is a bit advanced, it may enter the market faster than expected.
Entering the shrink film market must be timely and take pains. In the long run, market investment should be profitable. However, its important technical problems cannot be solved independently, so your production chain must include printer manufacturers, inks, and material suppliers.