Application of water-based ink in carton carton printing

In the call for protecting the environment, saving energy, reducing pollution, recycling safe production, my country's packaging printing water-based inks have ranked first among other packaging printing inks with its 35% dosage in just a few years.

Throughout the packaging printing inks, the more high-end, especially water-based printing inks, the stronger its printing characteristics, the narrower the scope of adaptation. ordinary batter starch, dextrin to shellac, casein, sodium lignin; rosin modified maleic acid resin, to styrene-acrylic copolymer resin, even polymers with core-shell structure network structure Emulsion resins, without exception, are called water-based inks.

In my country, the number of inks used in packaging printing products is increasing every year, especially in the form of screen printing flexible letterpress, but most of the paper substrates of absorbent media use gravure printing. In particular, plastic aluminum foil substrates used in non-absorbent media have only recently achieved printing on web materials by rotary machines. The advancement of this technology shows that ink painting has gradually matured. At present, the ink has been recognized as "non-toxic ink" by the American Food Drug Association. The rapid development of ink makes other inks hard to see. In the past, ink has poor gloss on paper, water resistance, poor adhesion, difficult overprinting, discoloration fading, products that are prone to edge warp uneven clothing have been improved. This is very advantageous for promoting the application of water-based inks on cartons cartons. In addition, ink wash have the characteristics of no explosion, no transportation risk, no pollution, no toxicity, etc., use water to adjust the drilling degree clean the printing equipment, which reduces the production cost labor intensity, reduces the safety risks for the production, transportation use units. .

① The film-forming substance in the ink adheres the pigment filler to the substrate. give the ink a standing non-stick body;

② Can make the ink have sufficient leveling, spreading gloss on the printing material;

③It has highly effective wetting agent wear resistance;

④ Maintain improve the dispersion of pigments printability;

⑤ It can have sufficient printing resolubility, but it must have certain water resistance after drying.

Changed the traditional water-based ink to use pure water-soluble polymer compounds (such as casein, shellac, polyvinyl alcohol resin, etc. as the ink connecting material), because only relying on water adhesion is resistant to friction water, so it is now flexible for rotation. Ink gravure ink systems use water-based ink binders such as acrylic acid, polynitrogen vinegar, etc., which has been changed glycol ethers in the past (which can metabolize harmful substances such as alkoxyacetic acid) to propylene glycol ether series (which are almost metabolized The toxic 1,2-propylene glycol eventually decomposes into carbon dioxide water with low toxicity. There is also an initiator-free water-based uv ink that will enter the market to prepare non-toxic water ink.

The relationship between printing conditions drying speed gloss

1. Water-based flexible water-based flexographic rotogravure printing paper for printing packaging paper bags, books, magazines, cartons, cartons, cigarette packs. In the past ten years, although the gravure paper water ink produced by high polymer acrylic resin can meet the printing requirements of high-end products with high printing quality requirements, but it can really meet the user's requirements for gloss, it is recommended to choose no trigger Water-based UV ink.

2. The temperature humidity of the printing workshop have a great influence on the drying speed gloss of the ink film of the printing. Temperature is the main factor affecting the oxidative polymerization, volatilization, strong ink film. Therefore, the difference in gloss between the southern coastal northern plateau regions after drying film formation in summer winter is about 1 times. In the two cases the relative humidity reaches 95% 65%, the drying time is almost more than twice different. At the same time, the dry humidity pH of the paper the carton itself will directly affect the drying time of the printed products.

3. Acidity can delay the oxidative polymerization of ink the formation of volatile solid ink film. If the alkalinity is too large, it will lead to internal wetness external dryness, which will affect the adhesion of ink on the surface of printed products.

4. Because oxygen air blowing baking in the drying tunnel is a factor that promotes oxidative polymerization volatilizes the solid ink film, the degree of ventilation in the printing workshop the stacking method of the printed parts are also related to the drying speed of the printed products.

The cause solution of the failure of ink painting

Hue is correct. The degree of ink drilling is too low the pigment content in the ink system is low the color purity is deviated. The ink precipitates during printing is poorly transferred. Mix the original ink, adjust the drilling degree to mix the ink before printing, check whether the printing plate ink roller are aging.

The viscosity is unstable. The ink is thixotropic, foaming, the solvent is volatile. The ink should be stirred evenly, then the appropriate amount of defoamer (0.2%) should be added to add the appropriate amount of solvent to achieve the balance of volatilization.

Poor drying. In the expected time, the blot should dry even stick to your hand. The ink has a high degree of drilling poor absorption of poorly dried base paper plastics fabrics. Dilute the ink, adjust the printing pressure to increase the temperature of the blowing drying tunnel, use quick-drying ink. adjust the dryness. Replace the substrate to replace the light version.

Blurred silhouette. The high-profile part of the printed product is blurred. The dots are false the tone is lost. The quality of the printing plate is high. The contact between the printing plate the ink roller is too tight, the drilling degree of the ink is large, the ink returns to the coarse ink. The drying is too fast the stirring is poor. The backing plate should be even even to adjust the printing pressure. When adjusting the ink drilling degree, the water alcohol should be mixed to reasonably stir the ink adjust the ventilation device. Don't blow it onto the ink roller the roller, increase the speed. Scrub with water containing monoethanolamine add 0.2% dimethyl silicone oil increase the proportion of coupling agent.

5. Graphic crushing ink extrudes out of the graphic. The quality f of the printing plate is too soft the pad elasticity is too large, the contact pressure is too tight, the ink privacy is too low, the ink mixing is poor. Pad the plate to adjust the height of the printing plate, adjust the printing pressure the pressure of the manual screen printing squeegee, adjust the drilling degree to water ink with high drilling degree exchange the ink with greater hardness stir the ink reasonably.

6. Poor transfer. Insufficient printing pressure The plate hardness is too high, the water resistance of the paper is too strong, the ink roller wears out. Increase the printing pressure. Use water-repellent ink to check the wear aging of the ink roller. Add TM-20. Coupling agent. Replace the metal anilox roller that blocks wear.

7. Difficult to overprint, multi-color overprint is allowed. The printing pressure of the road color ink is too fast after the road color ink is dried. The second color printing pressure should be increased, the color printing pressure should be light. Add the appropriate amount of TM-200S coupling agent. The privacy of the road ink should be reduced the dryness of the road ink should be adjusted the second color should be printed when the ink film is completely dry (overcoming the surface vitrification). protruding deforming, replace the paper.

8. Ink foaming, the foam overflows after the ink in the ink fountain of the printing machine circulates. Insufficient foam inhibitor in the ink system. Insufficient ink circulation, too much water, too much pump circulation, air leakage in the tube. The ink is too thin. Appropriately add antifoaming agent (0.2% mixes both internal external plasticized antifoaming agents) to reduce the pump circulation replenish the new ink so that it does overly dilute the inspection tube to prevent air leakage.

9. Chemical pinholes. Adding too much antifoaming agent will make the ink dilute the excessively low-privacy ink ink too much. Note that about 0.2% of defoamer is incorporated. It should be mixed with the original ink mixed before printing.

10. The printing plate is worn. The contact is too tight, the pressure is too heavy, the texture of the plate is too hard. Adjust the contact, adjust the printing pressure, replace the printing plate add a 3mm plastic foam sheet on the back of the plate.

11. Ink gelatinization. Use the wrong solvent (some active molecules begin to associate to form colloid-sized aggregates). Mixed with other types of ink, improper storage, wrong colorant used in ink, ink ages over time. Use a solvent with good solubility to add about 2% of silica gel 0.3% TM-200 coupling agent, seal store it, add an auxiliary agent with activity.

12. Paste sticky/sticky dirty during printing stacking after printing. Friction occurs on the transmission rod the film peels off causing fouling. The ink drying speed is too slow, the printing speed is too fast, the ventilation is too hot, the ink is too soft. Replace the hard ink add a solvent that evaporates quickly (ethanol acetone) to slow down the printing speed increase the air supply.

13. Ink fading Ink color fades during printing stacking. Ink system fillers have too much color there is a wrong pigment (acid is resistant to alkali). The printing carrier is too acidic. Ink pigments are heat resistant. Use quick-drying ink less use of drier ink. The pigments in the ink use heat-resistant light-resistant stable pigments, replace the non-dazzling calcium fillers. Add inorganic mica powder anti-ultraviolet absorber antioxidant about 0.1% to 0.3%.

14. Striped orange peel with uneven print. Ink ink leveling is too poor, too much plasticizer, thixotropy is too large, sometimes there are mesh stains, paper is flat, ink drill is too large, too much ink is too thin, too much water. Replace thicker ink, reduce printing pressure, replace water-resistant ink. Use opaque ink. Change the high-quality substrate with a uniform surface to increase the filling amount (such as talc can only prevent sinking but also improve leveling). Replace the ink with lower viscosity, do dilute the color too lightly to reduce static electricity.

15. Blotting (pulverization). The printed product is bound, moved wiped by hand. The ink color contaminates the printed product fingers. Due to improper adjustment of the ink, the resin in the ink system is reduced the solubility of the solvent the binder of the ink system is unbalanced. The wettability of the pigment filler is poor. The paper surface is too rough the aluminum plastic surfaces are too smooth. Increasing the resin content reduces the proportion of water as much as possible to balance the content solubility.

16. Poor tolerance. Poor water resistance, light resistance, alkali resistance. Use appropriate ink "The pH value of the strong ink film should be controlled between 7 7.5! Replace the light-resistant ink add 0.2% UV absorber inorganic mica powder to use soft ink.

17. Block the network block the version. The large f at both ends of the ink roller accumulates like ink residue. The pigments fillers of the ink system are neutralized are neutralized accumulated. The ink is mixed with paper scraps plastic scraps. Reduce the printing pressure, filter the ink adjust the ink supply. Use alkali-resistant fillers alkaline active additives, add the original viscosity of the appropriate viscosity to the printed ink to adjust.

Basic knowledge of ink storage printing process

1. After printing, the printing machine, ink roller, printing plate should be thoroughly washed, the wastewater should be treated. The ink fountain should be covered sealed to prevent it falling into dust. Note that the ink ink will be separated immediately when it encounters acidic water rust in the iron drum.

2. Ink should be kept in a cool place to prevent deterioration. Although it is water-based, it is forbidden to approach the ignition source due to the presence of alcohol in the solvent to prevent the heat volatilizing deteriorating.

3. Care should be taken after opening the barrel (can box), do bring impurities, use it as it is opened, to prevent the amine ammonia of the ink system being unstable after volatilization. Do use light-transmitting packaging barrels (cans, boxes) to prevent the ultraviolet rays invading causing instability in the oil.

4. If the gloss is bright, it can be adjusted by adding tung oil polymer resin plus acrylic resin magnesium salt TM coupling agent.

5. Ink ink are too low the fluidity is too large. Storage is easy to deposit printing is easy to sag. It is possible to add cheap aluminum salt white carbon black bentonite in an appropriate amount.

6. Ink ink drying speed (such as gravure printing for 3-5 seconds 100 seconds for drying) can be determined by gravure, embossing screen printing process.

7. For water-soluble printing inks that are difficult to clean, add triethyl thiamine TM-2005 coupling agent, finally add an inexpensive LLJ all-around solvent to increase the rewetting of the ink increase the true solvent to reduce the proportion of ink. For the case the anilox roller is clogged due to coarse particles, the ink can be re-filtered. The ink stains when cleaning the printing machine, printing plate, ink roller bucket tool are cleaned by filtration introduced into the ground. Avoid its pollution to the environment.