Many packaging materials have exquisite patterns and necessary text instructions, they are printed with ink, and the ink layer is between the surface film and the secondary film. Because the ink layer is protected by the surface film, it is not afraid of abrasion, scraping, there is no surface printing ink easy to fall off. However, sometimes there will be composite ink layer to transfer, and the original substrate film (generally BOPP, PETP or OPA film) fastness is very poor, the performance of the stripping force will be very low. There is also a case that after the composite bag is filled with some contents, especially the contents with aromatic, pungent or surfactant, after one, two weeks or months of storage, the ink layer will automatically layer, and even show the phenomenon of sticky ink.
The ink layer is not firm, when stripping the ink layer to transfer, the main reasons are:
(1) The surface treatment strength of the base film before printing is not enough, and the surface tension is low, even less than 38mn / m. Although the ink used is the inside printing ink, but its own printing fastness is not high, it is easy to pull off when using tape to pull off. If this is the case, it is necessary to use a substrate whose surface tension meets the printing requirements, at least greater than 38mn / m or reprocessed to more than 38mn / m.
(2) The printing fastness of the ink is qualified, and it can not be pulled down when the adhesive tape is used for stripping. However, when the ink layer is removed after lamination, the ink layer will be transferred again, and the stripping force is also very low. This phenomenon is not the reason for the surface tension of the substrate. We know that the fastness between ink and substrate depends on the affinity between the binder and the substrate in the ink. This affinity is the comprehensive embodiment of polar attraction, dipole moment force, intermolecular attraction or dispersion force. Strictly speaking, it is a physical force rather than a chemical bond force of chemical structure. In addition to the same physical force as the ink, there is also a much greater chemical bond bonding force than the physical force. Therefore, the ink layer through the adhesive and the secondary film between the fastness is generally greater than the ink layer itself and the substrate film. So in stripping, most of the ink layer will leave the original substrate and transfer. However, good ink on the performance of a higher peeling force, will not be 100% transfer. Bad ink will be 100% transfer, stripping force is very small. In fact, as long as the peeling force is high, ink layer transfer is not terrible.
(3) Only by using special ink can the quality be guaranteed. First of all, in the composite materials must be printed in the composite ink, not surface printing ink. The binder of printing ink is composed of chlorinated polypropylene, chlorinated EVA, chloroacetic acid copolymer and MP-45 resin (imported resin for printing ink). It has a good affinity for BOPP film which is widely used in composite materials. As long as the surface tension of BOPP film is higher, the printing fastness is satisfactory. And the surface printing ink of the binder is mostly a single polyamide resin, this ink is not suitable for composite products in the printing. Because of the cost, we found that some small factories use surface printing ink to make composite products. Most of their products will have the phenomenon of ink layer transfer and peeling force is very small.

The more high-grade composite ink suitable for inner printing is two-component polyurethane ink, which belongs to the same type as the two-component polyurethane adhesive used in lamination. Its fastness to various substrate films is much greater than that of the previous one. Moreover, it has ideal printing fastness to BOPP, PETP, OPA, aluminum foil and other substrates, and is very suitable for composite adhesives. As long as the proportion of the ink is appropriate, the ink It also has the ability of high temperature resistance and medium erosion resistance. It is the most ideal ink for solving the transfer of ink layer, small peeling force and heat resistance and medium resistance.

(4) On the premise that the ink type is a one-component composite ink, if you want to further improve the printing fastness, avoid 100% ink layer transfer, and maintain a slightly higher peel strength, you can add 5% weight "curing agent" into the composite ink. This "curing agent" is the curing agent in multi-functional two-component ink, which is the "curing agent" in the two-component polyurethane adhesive used in dry lamination. According to the feedback information from the units using this method, it has practical effect. However, here must be explained: only in good quality printing ink and does not contain alcohol or alcohol content is not much, can use this method, if the ink contains a large number of alcohol and other active hydrogen solvent, this method can not be used.
(5) In addition to the factors of ink, we can also choose the adhesive with strong permeability, which can increase the fastness of ink and substrate film. This kind of adhesive contains a kind of adhesive with small molecular weight. Driven by the solvent, it is easier to reach the surface of the base film through the ink layer than the glue with high molecular weight. This makes the ink not only rely on the physical binding force between itself and the base film, but also the chemical bond force of the adhesive to achieve higher fastness.
(6) Different substrates should be adapted to the special ink. At present, a large number of printing inks are suitable for BOPP film printing and lamination, but not suitable for PETP, OPA, aluminum foil and other substrates. For the back of these substrates, to use shenri ink company or Shanghai DIC ink company's century Xin special ink, can also use Jiangmen Toyo ink company's lamistar special ink, or Japan's Toyo ink company's mutis-set special ink, can also use new Oriental ink chemical group's two-component ink, but absolutely can't use surface printing ink.
(7) If the contents with erosive effect are packed, and the ink is sticky and separated due to the effect of the content medium on the ink, the high-quality ink with anti medium type should be carefully considered. Because this phenomenon is a quality accident that can not be controlled before the compound bag leaves the factory. It only appears after the packaged goods are stored for a long time. At this time, the loss caused can not be recovered. Therefore, in this case, the choice of ink, must be more careful, more cautious. For organic solvents, liquid pesticides and household chemicals with strong erosive effect, it is better to determine after testing.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.