With the continuous development of flexographic printing, people have more and more stringent requirements for the quality of flexographic products. How to improve the quality of printing has become the primary problem that puzzles the industry.
In flexographic printing, the liner plays a very important role, but different liners (double-sided tape) have different effects on the printed product, which will now be briefly described.
Main characteristics and classification of liners
The basic function of the liner is the sticky tape, which is to firmly stick the flexible plate on the plate cylinder so that there is no slippage between them.
According to the hardness, pads can be roughly divided into three types, namely: soft pads, neutral pads and hard pads.
The thickness of the liner should be consistent. The stable and uniform thickness is conducive to controlling the expansion of the dots and ensuring good printing results. The thickness of the liner used for narrow-width flexo printing is usually 0.3 mm. In plate making, liner thickness is an important consideration.
The basic composition of the pad
The liner is generally composed of an intermediate base material layer, an adhesive layer on both sides, single-sided or double-sided protective paper, etc. As shown in Figure 1.
1. The substrate substrate is the main component that determines the thickness and performance of the gasket. According to its material, it can be divided into film substrates and foam substrates. The film substrate is generally vinyl resin or polyester and paper, which has good elasticity and uniform texture, and is used for thin flexographic liners. The foam base material is generally polyethylene or polyurethane foam. The base material determines the elasticity of the double-sided adhesive. The base material is too elastic and is not ideal for field printing; the base material is too hard and the dot reproduction is not ideal.
2. Adhesive layer The effect of the adhesive layer is twofold, namely: firmly attach the printing plate to the plate cylinder, and adhere the protective paper to the surface of the substrate. There are two types of adhesives used in the adhesive layer: rubber and acrylic. The viscosity of the adhesive layer has a great influence on the service life of the double-sided adhesive. The viscosity of the adhesive layer is low. The plate is not easy to stick when used for the second time; the viscosity is too high. It is easy to damage the double-sided adhesive surface when changing the plate.
3. Protective paper The role of protective paper is to prevent the substrate layer from being scratched, to prevent dust, and to prevent adhesion, which is convenient for unwinding.
Selection of liner
From the compressibility analysis, soft pads have the most compressibility, followed by neutral pads, and hard pads have the least compressibility.
When choosing a liner, the following two basic elements should be considered first.
1. Printing materials
The printing materials of flexographic printing have a wide range, from soft plastic films to rigid glass products, from metal films to corrugated cardboard, etc. The selection of liners should first consider the extensiveness of the printing materials.
2. Print pattern features
Different liner patterns should use different liners. Field liner is best to use hard liner. The network cable version is best to use soft padding. If there are both solid and fine lines or small dots in the printed pattern, both should be taken into consideration and a neutral pad should be used.
Therefore, in actual production, it is necessary to reasonably select pads according to different printing conditions and process requirements.
Experiment 1 Relationship between pad hardness and solid density value
As the hardness of the pad increases, the solid density value gradually increases. When this phenomenon occurs, our analysis is mainly due to the elasticity of the pad: in the printing process, the normal printing pressure is given to the printing plate. Under the effect of this pressure, the pad and the printing plate deform simultaneously, but due to the better elasticity of the soft pad, the pressure on the printing plate is relatively reduced, so the ink on the printing plate is not completely transferred to the printing material, causing The printing density is small: the hardness of the hard liner is relatively large. Under the same conditions, the pressure of the printing plate pasted with the hard liner is greater than that of the printing plate pasted with the soft liner, so the ink The transfer is better; the elasticity of the neutral pad is between the hard pad and the soft pad, so the density value of the printed solid is also between the two.
Experiment 2 Relationship between liner hardness and dot expansion
The dot expansion value increases as the hardness of the pad increases. This is also mainly affected by the elasticity of the pad. The elasticity of the soft pad is higher than that of the hard pad. Under the same pressure, the deformation of the soft pad is much larger than that of the hard pad. The amount of deformation of the sticky printing plate, so when using a soft liner, the dot deformation is small, resulting in a relatively small dot expansion value.
In summary, we can draw this conclusion: it is better to use hard liners when printing on the ground. When printing fine lines and dots, it is more appropriate to choose soft pads, while neutral pads can make up for the shortcomings of soft pads and hard pads, and all graphics and text can be taken into account. In general, neutral pads are more widely used.
In actual production, the choice of liner should also consider the utilization rate of liner. Compared with the neutral liner, the hard liner has a lower surface viscosity, while the soft liner has the highest viscosity. When changing the plate, the hard liner has a lower viscosity when reused, and the plate fastness is poor; while the soft liner has a very high viscosity, it is easy to separate the middle layer of the liner when removing the plate, and it cannot be used again; neutral liner The pad can be reused several times. Therefore, from a saving point of view, it is generally more economical to use neutral pads.
Best flooring options for your kids
Our Enlio kids flooring not only looks great but is slip resistant and comfortable,making it so easy to clean.
Design For High Level Kindergarten, 3.0mm and 4.5mm thickness,7 Colors, more options for color choices.
Super wear resistant layer make it withstand long using life and anti-scratching performance.
For quality assurance: 100% pure PVC material, provides excellent shock absorption, slip resistance, sound reduction.
Advanced producing technology, our flooring owns a high dense structure and excellent compression resistant rate.
High-tech wear resisting performance processing technology, ensures wear resistance capacity and long life span.
Annual sales of over 4 million square meters. Preferred brand choice for professional sports venues.
No harmful substances, such as Formaldehyde, Soluble Volatile and Heavy Metals. ISO 14001 certified.
Remarkable anti-pollution capacity. Reduce the waste of natural resources by frequent cleaning.
Low maintenance cost, easy to clean without using wax.
Elastic cushion with stable support structure, ensures comfortable foot feeling and good optimal vertical force, thus provide excellent sports experiences for players.
Excellent shock absorption provides best protection for the player`s knees, spines, joints and cartilages.
Friction coefficient rate is between 0.4-0.7. Easy to balance the force of ground grip and good at slippery resistance. Suitable for different kinds of Ball games and other sports.
1.8 meter in width to reduce welding connections. With elegant apperance and stable structure.
With operable weight, the whole roll could be directly laid on existing concrete grounds or wooden floors. The overall visual effect is very good.
Kids Room Flooring,Pvc Kids Flooring,Kids Flooring,Kids Playground Flooring
Shijiazhuang Enlio Sports Goods Co., Ltd. , https://www.enliosports.com