The hottest scientific exploration of ink research

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Scientific exploration of ink research and development, efforts to promote printing quality

recently, in the process of continuous heating up of water-based printing ink rising in the ink and packaging printing industry, when one or another failure has been put in front of people to deal with, some enterprises asked us to help deal with it, but because the author's work schedule is very tight, so I have to borrow a corner of your journal and write to them. I hope to propose different solutions to the problems. As the saying goes, if you want to burn jade for three days, you must wait for seven years to distinguish the materials

1. The director of zhushangda factory in Jiande City, Zhejiang Province asked:

Liu Gong, what is the problem of ink thickening in the printing process

answer: the thickening of ink is almost the same in the process of packaging and printing, even in the process of manufacturing or storage, but it does not deteriorate. The former is related to the temperature produced by the ink under the action of printing machinery, but also to the natural environment. As the ammonia in the ink system evaporates after carbon dioxide, a certain amount of heat generated by it is consumed (but the consumption varies), at this time, the surface viscosity of the ink increases, resulting in the reduction of pH value and thickening; In addition, due to the large surface force of ink, the volume of pigments and fillers will swell and thicken after storage for a period of time

in addition to the above phenomena, once the ink is packaged and printed, the formation of its graphic ink film will be greatly slowed down, which will lead to printing failures such as stacking, dirty plates, and overlapping dirty plates. This phenomenon is mostly reflected in ink printing products with modified rosin as binder

2. Pan Zhiwen, chief of Sichuan development company, asked:

teacher Liu, apart from white ink, ink is easy to thicken and excessive color is often lost. What's the matter

answer: this phenomenon is similar to the problem of 1, but the difference is that this kind of fault mostly occurs in printing ink with acrylic resin as binder. I once made a detailed statement in the article "rough discussion on the causes of the dilution peak of packaging and printing ink". In short, the acrylic monomer in the acrylic resin in the ink system does not reach 30%

as for point loss, its printing fault is that in recent years, people are pursuing the shallow version of ink printing and quick drying of ink. Due to the water-based ink made of acrylic resin with a certain and unmistakable acid value as the binder, it is easy to lose the rewetting micro solvent due to the introduction of water-soluble crosslinking agent, resulting in the drying of the ink that has been filled in the printing image and text hole, so it is not easy to transfer to the substrate

3. Hu Xiuzhu, director of Shijiazhuang, China Banknote Printing Factory, asked:

teacher Liu, what is the problem with the impermeability of anti-counterfeiting offset printing ink

answer: first, the high polymer molecular weight of the ink system is too large, and the viscosity is too high; Second, the dispersion of the ink system is poor; Third, the ink is lack of penetration additives; Fourth, the substrate is too dense and so on

4. Boss Huang Wei of Sichuan Longmo printing materials company asked:

master, how can we improve the printing ink film which is too hard to rub

answer: first, choose flexible materials on the printing substrate; Second, choose the resin with low softening point or soft property as the binder resin; Third, add plasticizer or toughening agent in the ink printing process; Fourth, plasticizers are introduced into the esterification process of resin production

5. Mr. panjinhan, Jiaozuo City, Henan Province asked:

Liu Gong, what is the reason for the poor gloss of the ink film in ink printing

answer: first, the resin content in the ink system is low, or the leveling property is poor; Second, water makes the pigments in the molten ink system opaque under pressure; Third, the substrate is too rough; Fourth, the pressure of printing is too small; Fifth, the solubility of water or water + alcohol media and resin in the ink system is not good; Sixth, the resin in the neutralization ink system itself does not reach a certain degree of transparency

in terms of resin alone, under the same conditions, whether esterification or amination, the faster the stirring speed is, the higher the molecular weight is. Second, the longer the constant temperature, the better the stability. Of course, if lotion is selected as the ink binder for the ink system, the faster the dispersion and stirring speed is, the higher the molecular weight (i.e., the smaller the particle size) is, because the high-speed stirring and dispersion often destroys the core-shell structure of lotion. In short, this is the main reason for the reduction of the gloss of the graphic ink film after ink printing

6. Wang Yanzhi, director of Zaozhuang City, Shandong Province, asked:

Liu Gong, is there a brand of water-based resin with low ammonia smell that can be used in both paper products and plastic (non absorbent) substrates in the current market

answer: Yes. Such as domestic ml-302 resin, LX resin, etc. Although it is not very good, it can be used universally. Because the price is only two-thirds of that of similar resins, and users only choose one kind of resin to produce packaging printing ink, it can be used as both surface printing and internal printing. It greatly reduces the economic risks of ink and packaging printing enterprises

7. Manager Wang Dongshan of Foshan City, Guangdong Province asked:

Liu Gong, our company has completed the first domestically developed laser engraving machine in ceramics, the first epoxy foam gravure regeneration roller, the first high-precision roller printing machine, and the first batch of high-quality water-based printing oil (water-based glaze oil), but it is not fully equipped. Excuse me: can you help complete the ceramic water-based glaze oil and explain what kinds of colorants are used in ceramic water-based printing inks

A: first of all, I am very surprised that your company can achieve many results in 2007. And take the opportunity of reply to express heartfelt congratulations! At the same time, I am glad to promise to help your company find the pursuit of dreams in ceramic printing products. As for the colorant of traditional manual silk screen printing on ceramics and the water-based engraving and printing of intaglio on the epoxy foam of the sleeve by laser, the colorant is the same as that of metal oxide. Generally speaking, (1) red is Cadmium Selenium Red, etc; (2) Yellow is antimony, lead, yellow, etc; (3) Cyan is cobalt aluminate, etc; (4) White is titanium oxide, etc; (5) Black is iron oxide, etc; (6) Gold is metal gold, etc; (7) Silver is metallic silver or palladium, etc; (8) Green is chromium oxide green, etc; (9) Purple is nickel oxide, etc.

in a word, ceramic packaging materials or decorative materials will implement the standard of color glaze for building and sanitary ceramics in the building materials industry standard of the people's Republic of China, namely jc/t1046 1-2007, from November 1, 2007

8. Boss liaojianxiong of Zhongshan City, Guangdong Province asked:

Liu Gong, in which direction will the future packaging and printing ink consumables develop

answer: domestic water-based paper and water-based plastic packaging printing ink consumables have made breakthroughs in ink film adhesion, gloss, smell, water resistance, rubbing resistance, drying speed, non shrinkage and other aspects of ink this year. In addition, in the future, the laws and regulations on environmental protection will be more explicit, detailed and strict, and the future packaging and printing ink consumables will certainly develop towards the raw materials required for water-soluble or water-based packaging and printing inks (including ceramics, stone, cement, fabric and other substrates)

9. President Li Yeyue of Yiyang City, Hunan Province asked:

Liu Gong, what's the matter with the easy precipitation and sedimentation of water-based tipping paper ink

answer: first, the wettability between the binder, colorant and filler in the ink system is poor; Second, the viscosity of the binder in the ink system is low, especially the solid content of the resin is too small; Third, the ink production environment temperature or grinding cycle temperature is high (for example, the ink is not restored to normal temperature and then packaged and sealed); Fourth, the precipitation and precipitation caused by the unbalanced solubility of the binder during production (not transparent) or the unscientific formula sequence. The binder cannot bear the gravity of the pigment and filler

10. Zhang Jike, an engineer of Xinxiang Tianlong company in Henan Province, asked:

teacher Liu, how to remedy the freezing of the ink when printing with surface printing ink

answer: if it is a printing ink with polyamide resin as binder, you can add rosin antifreeze resin, n-Propyl Acetate or calcium chloride; If it is a printing ink with other resins as binder, ethylene glycol, propylene glycol and glycerol solvents can be added

11. Shanghai Wang Wei asked:

Liu Gong, what role can wax used in water-based ink be easily identified by using signs or other ways

answer: first, prevent the ink film of printing text from rubbing dirty and crystallizing; Second, improve water resistance; Third, improve the rubbing resistance of the ink film; Fourth, prevent ink from caking

12. Liu Xin, Xiangfan City, Hubei Province asked:

Liu Gong, what is the main purpose of LJJ resin

answer: because LJJ resin has a wide range of sources and is non-toxic, its first purpose is to be used for ink printing; Second, for textile printing and dyeing; Third, it is used for paint and coating; Fourth, it is used in four aspects, such as food and medicine

on the other hand, the development and application of this resin provides a broader choice space platform for our existing traditional products, and also provides an opportunity for people in the mainland or mountainous areas to get rich. Although the cost of R & D and application test is not much, there is still a long way to go to let people know it and accept it. If we choose LJJ resin, the technical barrier of environmental protection is another matter

13. Chenyupu, Danjiangkou City, Hubei Province asked:

Liu Gong, why is our modified waterborne rosin resin dark in color and low in softening point

answer: first, the color of rosin is deep; Second, the environmental temperature of the inventory is high or the packaging is not sealed well; Third, although the melting temperature is not high during modification, the melting time is too long or the reaction is too fast after maleic anhydride is added, especially when air oxidation is introduced, resulting in the deepening of chromaticity

as for the deep color and low softening point you proposed, in addition to the above effects, it seems to be contrary to the academic statement. The author believes that the situation that leads to deep color and low softening point is often: in the formulation design of the product, in addition to the few reactive materials, the temperature requirement is low and the constant temperature time is short. As a result, the acid value is high and the softening point is not increased

14. Zhuyongjie, Wenzhou City, Zhejiang Province asked:

Master Liu, can you help me adjust the pet ink formula to have adhesion fastness

answer: you can introduce cross-linking accelerator into your original formula, or you can choose thermosetting tackifying resin suitable for composite glue as auxiliary resin. Remember, there is no need to add tackifying resin to polyamide resin, alkyd resin, polyurethane resin, epoxy resin, etc

15. Boss Tang of Guanghan City, Sichuan Province asked:

Liu Gong, what is the matter with the cement bag breaking after the cement is canned from normal temperature to 130 ℃ and then reduced to normal temperature

answer: in China, most of the cement plastic woven bag manufacturers currently produce recycled (i.e. recycled waste plastics). In particular, it has been recycled for as many as 20 times. We know that once PP plastic is exposed to oxygen or sunlight, its UV performance will deteriorate (aging)

16. Wang Yong, Zongyang County, Anhui Province asked:

Liu Gong, what is the reason for the surface precipitation after the ink barrel is opened

answer: in short: in addition to the reasons I mentioned in 9, the main reason is the poor wettability of the binder components in the ink system to the colorants and fillers in the ink system. Especially when the specific surface area of the pigment is large, this result will be aggravated and accelerated. Another situation is that the ink manufacturing filter is not restored to normal temperature or contains excessive moisture, which will also occur

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