Exploring the application of natural ink anti-abrasion agent
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First, how much joy in ink printing?
When packaging and printing technology pursues environmental protection effects, people will be the first to introduce water-soluble ink products. The biggest features are: (1) no pollution to the environment; (2) wide source of materials; and (3) low cost, recognized green products. However, after long-term practice, due to technical limitations, it is often encountered: 1 set of color difficulty; 2 gloss difference; 3 warping angle; 4 not water immersion; 5 not abrasion; 6 pairs of metal such as aluminum foil and The adhesion fastness of the polyolefin film is not good enough, and the adaptation range of the printing ink is questioned. This old and difficult problem has seriously plagued the promotion and application of this product, directly affecting the progress of ink theory knowledge. Now through the analysis and research of modern ink printing technology, it is proved that the appearance of these special faults is related to the surface tension of the ink. In order to overcome the above problems, after nearly two decades of exploration, the author summarized the mechanism of the penetration of the aqueous ink film formation process and the natural ink anti-abrasion agent against osmotic pressure, so as to discuss with the ink and printing industry colleagues.
Second, the action mechanism of ink anti-abrasion agent
1. Anti-abrasive material
The raw material of the product is firstly subjected to physical methods, filtered, concentrated, separated and precipitated - that is, recrystallized from crude product, and chemically removed impurities such as alkali metal and alkaline earth metal sulfate and sodium carbonate to form a sodium compound.
- Anti-abrasive raw materials.
Since it is considered that it can be purchased almost everywhere in nature, especially in the packaging and printing products, it is necessary to prevent the ink film penetration of the packaging printing ink, control and reduce the surface tension and the amount of the binder in the ink system, and the author has gone through Hubei, The repeated comparisons between packaging and printing enterprises in Hunan, Guangdong, Fujian, Zhejiang, Shanghai, Jiangsu, Shandong, Liaoning, Henan and other places suggest that this re-dissolving neutral anti-abrasive agent is still natural and inorganic, without any side effects. of. It can not only greatly improve the gloss and anti-friction of the ink film of the package printing, but also one of the elements of the world's simplest method, the lowest cost and the human body.
2. Mechanism of action of abrasion resistant agent
Excellent packaging printing ink graphic ink film, not only has the above conditions, but also should add PH buffer solution in the ink system, the purpose is: under certain conditions can also resist the interference of external acid or alkali, but not because of joining A small amount of acid or alkali to change the pH of the ink to maintain the stability of the ink liquid pH within a certain range. Especially when the binder in the linear structure of the ink system is added, the ink can be cross-linked - it can act as an in-line molecular bridge, so that multiple linear molecules can be bonded to each other to form a network. The most inexpensive aqueous ink auxiliaries of the structure, the most obvious is that the degree of branching is greatly increased several times, even dozens of times, and the range of packaging printed products is expanded and the cost is reduced.
We know that the instability of the ink film of the printing ink is mainly caused by the imbalance of the osmotic pressure of the ink. The main component that is usually capable of maintaining ink balance is a neutral crosslinker. A surface phenomenon that lacks cross-linking to maintain ink stability is a substrate with a large water content and a rough surface of the ink, which can cause the water in the ink system to penetrate the resin in the binder into the substrate, resulting in poor gloss of the printed and printed ink film. Resistant to rubbing, etc. When we have a molecular weight of more than 106, a relative density of 2.1/25 ° C or higher, a melting point of nearly 800 ° C, and a boiling point that is unbelievable, it can be imagined from the phenomenon of dissolving in water, glycerin and alcohol: The cross-linking auxiliary can not only improve the swelling and gelation of the ink during the production or use of the ink, but also improve the heat resistance of the packaging printing ink. No matter whether it is in high temperature production or in a complex environment with low temperature operation, bubbles will not appear due to the addition of the product, causing pinholes and releasing gas, and will not cause the residue of the ink film in the image. Migration, discoloration and fading.
The author learned in a large number of experiments that when the temperature exceeds 300 ° C, it is easy to decompose and release oxygen. This oxidizing property, such as carbon, sulfur, phosphorus, and organic matter, causes a violent explosion after mixing and impact, but the oxidizing property of the liquid as an anti-abrasive agent for re-dissolving the ink is much weaker than the solid, not to mention the solidity. The requirement for packaging printed products to exceed 300 ° C has not yet occurred.
3. The principle of printing ink film
We carefully review the packaging and printing experience in the past two thousand years. Although the printing methods are different, the formation of the graphic ink film is also various, but the basic basic theory is: after printing, the graphic ink film on the substrate is fixed at the printed position, and the scientific and technological community is often called physics. Two major categories of adsorption and chemisorption. That is, the physical adsorption mainly attracts each other by the interaction between the ink and the molecules of the substrate, and generally the heat absorption is small; and the chemical adsorption attracts each other with a force similar to a chemical bond, and the heat absorption is generally large. As a kind of adsorption phenomenon of gas or solute on the surface of liquid or solid ink, in our daily packaging printing, since the adsorption force of the ink is often greater than that of the substrate, the ink that has been adsorbed by the substrate is not easily released - that is, powdered , pinhole, drop block, infiltration, etc., otherwise the opposite. This is because the hydrogen bond of the packaging printing ink has undergone a chemical change on the substrate and no longer has the original character (state), so it is often irreversible when the aqueous ink anti-friction agent is added.
Why the packaging printing ink system can only pass through the dispersion medium - water (solvent) and ammoniated resin molecules / colloidal solution (professional binder), but not through pigments (colorants) and filling. The molecules, so that the molecules of the dispersion medium are separated from the colorant molecules? Because the dispersion medium spreads out through the substrate as soon as it is printed. This phenomenon is called penetration of packaging printing ink. Strictly speaking, the infiltration is mostly a dispersion medium, and the dispersion medium is mostly a solvent. When two different concentrations (solvent of different solubility in the ink system and different resins) are separated by a fine particle colorant dispersed with different dispersibility, and the ink dispersion formed by grinding in the medium is separated by the substrate The solvent in the lower concentration binder solution can also penetrate into the higher concentration solvent, and most of the pigment and filler remaining on the surface of the substrate are often referred to as suspension, and the binder in the dispersion medium ( Here, only the resin) is small or unstable, so it is easily washed away by water or other solvents or rubbed off.
The above-mentioned failure occurs (infiltration) and the gloss of the graphic ink film is lost. The use of natural ink anti-friction agent can make up for the defects of the ink film after molding (ink penetration, floating color, poor gloss, water resistance, warping angle, low color brightness, low chroma, poor print flatness and difficult to print more than one version) Color high-speed overprinting, manual blocking and program-controlled slitting, and low quality of mechanized labeling, etc.). The advantages of the ink anti-friction agent are used to promote the balance between the solvent (water, alcohol), resin, pigment, filler and substrate in the ink system. This is called extra pressure to achieve the dreams of the world for nearly four decades.
The academic community expresses additional pressure in X letters. The amount of ink anti-abrasion agent determines the size of the osmotic pressure and the concentration and temperature of the binder in the packaging printing ink system (including the pH value, temperature, flatness, water content of the substrate) and the environmental temperature of the printing workshop. ,humidity. An ideal water-soluble printing ink binder has the following relationship:
In the formula, XA' is a mole fraction of a solvent (water, alcohol, etc.) in a higher concentration ink binder, and XA is a mole fraction of a solvent (water, alcohol, etc.) in a lower concentration ink binder. A is the molar volume of the solvent. If the low concentration ink binder is replaced by a pure solvent, XA = 1, so the above formula can be turned into:
In addition to the general consensus on the mechanism of action of ink anti-abrasive agents, it is not uncommon for the pH value to be controlled, the resin content of the ink film system to be too small or the binder to be unscientific in the ammoniation reaction, and the above-mentioned malfunctions are also common. Although the above-mentioned faults are attributed to the poor adaptability and instability of the ink, in view of the different ink brands in the domestic and foreign markets and the different opinions published in the various printed and printed newspapers and periodicals, an ink additive ink anti-abrasion agent that can become a road cargo has yet to be packaged and printed. , packaging and printing industry and commodity packaging customers and consumers to improve together. That is to say, the material source is sufficient, the purchase price is low, and the handling of the fault is simple and easy, and it is immediately available with the use. As for whether you can choose the principle of eliminating the printing failure mentioned above to carry out formula design and expand the scope of application - no longer to explore and affect the normal marketing business of packaging and printing, still need to reach a consensus to be more green The practical meaning of the type ink.
Facing the different ink brands researched and developed in different regions and different manufacturers, scientifically designing and producing a new environmentally-friendly water-soluble packaging printing ink product to help China and the world packaging printing ink enterprises, especially packaging and printing enterprises. Preventing the occurrence of the above-mentioned faults is also conducive to inhibiting the production and operation risks of failure of the printed and printed products due to the inferior ink, such as foam, pinholes, white spots, shrinkage holes, warp angles, penetration, floating color, and color loss.
Third, the application prospect of ink anti-abrasion agent
For thousands of years, after a formula is designed and used in different processes for ink production and packaging printing, occasionally there will be one or the other printing defects (faults)? But after choosing different dispersion media or different substrates and different packaging printing processes, the printing defects are gone?
When we choose another formula design and use a process different from the above, there is no fault that often occurs in production. To adhere to a so-called scientific theory that is universally applicable, first understand the materialistic point of view. Today's world, breaking the rules of the past, picking out the auxiliaries that can suppress these faults (to compensate for the lack of ink stability), the substrate (such as The difference between pH and whiteness and the surface tension of the ink is crucial. In a word: If something goes wrong, it will seize the reason to deal with it.
The author arbitrarily believes that there is no universal additive in the world, but the anti-abrasive agent for water-soluble packaging printing ink is one of the most widely used and most affordable additives. Only the application of ink is very small. Not all faults are attributed to the quality of ink products. It should also be neglected by the quality of the substrate, mechanical pressure, operation, environmental temperature and humidity.
Today, before we have found a long-term and effective water-based packaging and printing ink product, it is an effective and sensible choice to apply ink-based abrasives. This will break the existing packaging printing ink usage pattern, and its prospects are immeasurable.