First, the transfer layer burst color paper requirements?
Answer: Generally, the fiber of the paper is long fiber, and its flexibility is good. Conifer and loose leaf pine are the most suitable. It needs to be arranged vertically according to the fiber direction so as to basically meet the requirement that the transferred paper is not easily discolored after being cut into small pieces and is not easily distorted and deformed.
Second, the transfer layer burst color on the moisture content of the paper have any requirements?
Answer: The water content of the bottom paper is too high, the indoor constant temperature and humidity are unstable, the transfer paper is variably typed, and the edge and convex shape of the leaf edge phenomenon occurs. The moisture of the transferred paper will be released to varying degrees as the storage and temperature changes over time. However, if the moisture content of the transferred product is too large, the paper fibers will harden and become brittle. After die-cut indentation, the paper fibers hardened at the indentation are destroyed to varying degrees. The general technical requirement for the transfer of moisture in paper is: 6%. The temperature control of the printing shop is: 18-25 °C, humidity control: 60 ± 5 °C is appropriate.
Third, the transfer layer burst color on the glue What are the requirements?
A: At present, most of the transfer paper used in China is a wet transfer method. That is, transfer glue is applied to the aluminum layer or paper surface of the transfer film, and then it is compounded with paper or a transfer film. After oven drying, it is peeled offline or connected. Direct stripping compound, transfer method. The requirements for the use of water-based glue for wet transfer are generally the following: Initial drying performance, initial dry viscosity, directly affect the peeling effect; drying performance, directly affect the adhesion fastness of the aluminum layer; colloidal film forming performance, water resistance (dry After the water is not easy to re-dissolve), anti-solvent properties, anti-ultraviolet radiation performance, anti-friction, anti-high pressure, high temperature resistance; dry not brittle, etc., directly affect the transfer layer burst color.
Fourth, the transfer layer burst color on the amount of glue coating requirements?
A: The adhesion of the aluminum layer on the transfer paper surface mainly depends on the adhesive properties of the glue and the amount of coating. At the same time, the amount of coating will directly affect the color popping phenomenon; the amount of coating is too small and the glue penetrates into the paper. The amount is also small, the transfer of aluminum layer is not easy to peel off completely, the film layer after drying is thin, and it is not easy to resist strong pressure; when the coating amount is too large, the paper and film are easy to be squeezed when compounded, and the temperature of the oven does not prevent the film from drying out. Relatively poor adhesion to the aluminum layer is not strong; depending on the paper to choose a different degree of coating, for example: 225g/m2 single-sided coated white card paper, the surface finish is relatively high, relocation arrangement dense, feel Stiffness is strong, the paper surface of the instantaneous absorption performance is poor, the amount of glue is not easy to be too large, generally: 1.5-2g/m2; relatively poor surface finish paper is generally: 2-2.5g/m2.
5. What are the requirements for the drying system for the color of the transfer layer?
Answer: The length requirement for the drying system is: 12-16m is most suitable, and the temperature zone is at least 3 groups. The 4 groups are the best. Ventilation, ventilation, to be relatively large, the hot air directly blows the back of the composite paper, at the same time according to different boot speed to adjust the temperature of different drying tunnel, the speed is slow and the temperature is correspondingly low, otherwise. The optimum temperature of the oven is: the speed is 100-125m/min, the first temperature zone of the drying tunnel is set at 100°C; the second temperature zone is set at 110°C; the third temperature zone is set at 110°C; the fourth temperature zone is set Set 90 °C.
Six, UV drying system on the impact of color explosion?
A: The light source released by the UV lamp is a UV light source. The UV light has strong stringiness for general prints. The higher the power of the UV lamp, the greater the stringiness is, for example: dark red and black. , dark blue, etc., the color of the reflected light is not strong under the same conditions drying performance is relatively fast. The ink is printed on the thin and thick on the print, and the light intensity, in contrast to the color, affects the stringency of ultraviolet light to a different degree. The reflective intensity of the aluminum layer is higher than that of the general UV ink, but the reflective intensity is greatly discounted after being covered tightly by the ink. When the ultraviolet rays penetrate through the aluminum layer, about 30% of the dried film-forming colloids form different degrees of damage, resulting in an increase in the color burst rate.
7. How does the indentation damage the glue after it is dried and formed into a film?
A: After the transfer of paper after a strong indentation, it is generally very easy to burst color (explosive color - refers to the pressure burst aluminum layer, due to ink covering the surface of the transferred aluminum layer, the visual more obvious burst color), while the glue has a higher The request. For different grammage of transfer paper, the film forming requirements of the glue used after drying are different, the temperature of the drying tunnel is determined, and the drying rate of the glue is controlled at about 80%. However, the colloidal tantalum has a strong tackiness (thickness is strong and easy to transfer aluminum layer stripping). Incompletely dried film-forming glue after a strong indentation, the color burst rate is relatively low. On the contrary, the filming of glue is rather poor, and it is easily damaged by strong indentation after being completely dried, resulting in a popping phenomenon.
Eight, transfer aluminum (aluminum) layer thickness and thickness of the color impact?
A: The thickness and thickness of the transferred aluminum layer will affect the color bursting effect in different degrees. The thin aluminum layer can not cover the slight defects on the surface of the BOPP or PET film, and the quality of the transferred film will be affected. When the surface of the paper is transferred to the surface of the paper, the concentration of aluminum molecules is also relatively small, resulting in obvious unevenness on the surface of the paper. Vacuum aluminum plating has its molecular arrangement in an uneven state. Aluminum molecules are tightly hooked together to form a thin dense layer. If the thickness of the transferred aluminum layer is less than 200A, the aluminum layer is strongly indented or 180 degrees folded. After the song, the fiber of the paper will slightly break the aluminum layer, and the ink layer will also be damaged.
Nine, ink printing thickness of the transfer layer surface color impact?
A: For gravure printing; the printing thickness of ink mainly depends on the engraving depth of the printing plate to control the printing volume of the ink, the number of engraving lines and the angle of the engraving needle to determine the engraving depth, different prints, different printing processes, and printing plates. Different engraving process, the printing thickness of ink is not the same. Connection gravure printing machine speed, ink viscosity is low. Compared with the same conditions, the ink sheet of a single sheet gravure printing machine should be thicker. However, the thinness and thickness of the ink layer can affect the color bursting, which is mainly determined by the soft and hard properties of the resin oil contained in the ink. At present, the system of gravure printing ink produced by many domestic ink manufacturers is suitable for printing performance. More extensively, for the discoloration phenomenon of the transferred product, the ink formulation has also been adjusted accordingly. No matter whether the thickness or thickness of the gravure ink layer will not affect the color burst.
X. What should be taken care of in the selection of glue for avoiding the explosion of printed products?
A: One of the most common and difficult problems is to change the color of printed products. However, the selection of glue for transfer and the quality requirements for glue are relatively high. Such as the glue's initial drying performance, viscosity, adhesive strength, film-forming properties, odor, folding resistance, solvent resistance, high temperature resistance and so on. Only good adaptability can produce the ideal transfer product.
1. Requirements for the initial dry performance of glue: After the composite paper passes through the oven, the temperature of the oven is allowed to dry under a certain temperature control condition. The glue after the initial drying is bonded to the paper and the transferred aluminum layer, and the adhesive is firmly bonded. The degree is sufficient to completely strip the transferred aluminum layer.
2. Viscosity of glue: At present, there are many domestic equipments for producing and transferring paper, such as dry compounding and stripping; wet compounding and peeling; film coating or paper coating; no matter which method is used to process and produce transfer paper. The control of the viscosity of the glue is more important. The viscosity of the glue is too low. When the speed is too fast, it is easy to squeeze the glue through the composite roll and it affects the adhesive strength of the colloid. If the viscosity of the glue is too high, if the speed is too fast, the coating will not affect the transfer of the aluminum layer uniformly, resulting in incomplete peeling. Therefore, it is necessary to select an appropriate glue viscosity according to different compounding methods, drying methods, and coating methods.
3. Film-forming property: The glue in the transfer paper cannot be completely dried, but its adhesive force after film formation needs to reach 80N, which is enough to adhere the adhesive force of the aluminum layer to the standard of 50N pull force. The film forming property of the glue can directly affect the effect of the discoloration of the transfer paper. The good film-forming glue can enhance the flexibility and folding resistance of the paper surface, and at the same time, it also reduces the color burst rate.
4, solvent resistance: transfer paper is divided into the following layers: bottom paper, glue, aluminum, varnish. The film-forming glue is generally poor in solvent corrosion resistance, and its corrosion resistance time and corrosion resistance mainly depend on the anti-corrosion additives added in the glue to fully protect the film forming property of the glue. Solvents used in gravure printing are mixed high-boiling polar substances with strong corrosiveness, but the volatilization rate is relatively fast and can be volatilized instantaneously under suitable high temperature conditions of 65°C to 90°C. The film structure of the glue will not cause too much damage.
High-quality transfer paper requires high-quality raw and auxiliary materials and advanced technology to produce environmentally friendly, high-grade, and exquisite products. Focusing on environmental protection and transfer products, you, me and his body and mind will be very healthy.
Source: Jin Li Group Li Lianjun