Analysis of printing failure of the hottest woven

2022-08-09
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Analysis of printing failure of woven bag ink

release date: Source: China paper

in daily life, there is a kind of packaging products that are widely used, which is woven bag 7. Clean and check the impact sample notch broaching oil pump, bearings and various valve components. Sometimes there are some problems in the printing of woven bags. Today, China paper industry takes you into the printing of woven bags with ink to introduce the relevant contents in detail

I. poor adhesion

fault cause: 1 The surface of the substrate and the surface of the lamination or woven bag are too smooth (untreated or poorly treated). 2. Oil will eventually realize the closed-loop of the whole lithium battery industry chain. The complex of ink (i.e. additives) is improperly selected or insufficient. 3. The dissolved hydrogen bond force of the ink system is too different from that of the woven bag substrate. Troubleshooting: 1 The surface of woven bag substrate reaches about 38 dyne. 2. Add 5% chlorinated paraffin before stretching plastic braided wire. 3. The selection of ink should be very careful (of the same nature). 4. The ink should be used properly, and the one with low viscosity and high resin content in the ink system is better. 5. Increase the printing pressure

II. Print adhesion

cause of failure: 1 Sticking bags or sticking after rewinding when printing and stacking. 2. Because the printing speed is too fast, the rewinding is too tight. 3. The angle of the drying device is wrong or malfunctions. 4. The ink dries too slowly. 5. The storage stacking weight is too heavy. 6. The temperature is too high and the cooling is not complete or the ink is not heat-resistant. 7. The ink is too thin and permeable. Troubleshooting: 1 Adjust the printing speed and check the angle of the drying device. 2. Improve the dryness of the ink (or increase the ethanol 90 + ethyl ester 10% mixed diluent). 3. When printing, the stacking shall be less or the storage and stacking load shall be light. 4. Reduce the temperature of the workshop or warehouse (open the windows and doors to make the air convection, etc.) and replace the heat-resistant woven bag ink. 5. Add raw ink to improve its viscosity or add a diluent solvent with small molecular weight and fast volatilization (it is recommended to use the special diluent produced by the ink factory)

III. residual odor

fault cause: 1 Materials with odor in ink. 2. Ink deterioration. Troubleshooting: 1 Try not to use smelly raw materials. 2. Add spices (masking agent) and prevent impurities from penetrating into the ink system. 3. In ink production, pay attention to the solubility of the mixed solvent to the resin, or store the ink in a ventilated and cool warehouse

IV. poor film formation

fault cause: 1 The printing speed does not match the drying device or the dryness of the ink. 2. Misuse of diluent. 3. The drying property of the ink itself is not good (such as too slow or too fast). Troubleshooting: 1 Increase the blowing or increase (extend) the post printing conveyor belt. 2. Adjust the printing speed (pay attention to the ink film thickness after printing). 3. Replace the fast drying (film forming) ink. 4. Change the ink. 5. Dilute again or add solvent with fast volatilization rate

v. blocking

cause of failure: 1 It is mainly the drying of the ink on the printing plate that makes the ink transfer poor. 2. Mixing of plastic or paper scraps. 3. Ink scaling. Troubleshooting: 1 Adjust the blowing angle (do not blow directly onto the printing plate). 2. In addition to changing the substrate, the base paper, plastic or film should be mixed with the ink bucket and separated on the upper side of the printing machine. 3. Replace the ink with a new one or add 10% antioxidant in the ink bucket

VI. through printing or migration

cause of failure: 1 The ink is too thin (that is, the viscosity is too small). 2. The paper or plastic substrate is loose and thin. 3. Too much ink. 4. The stamping is too heavy. 5. Film forming and drying is too slow. Troubleshooting: 1 Add raw ink or thickener. 2. Replace the dense substrate. 3. Change to dry ink or add fast volatile solvent. 4. Adjust (reduce) the ink supply. 5. The stamping should be light

VII. Color bleeding

fault cause: 1 There is color on the edges of printed pictures and texts (generally caused by the use of dyes in the ink). 2. The pigments used are mismatched or the ink has deteriorated. 3. Too much thinner is used, especially the miscibility between thinner and ink is poor. Troubleshooting: 1 Add gold transfer oil or coupling agent to the ink. 2. Choose solvent (such as alcohol solvent) type pigments or replace with new inks. 3. Use as few thinners as possible, especially solvents that are miscible with ink

VIII. Matte ink film

cause of failure: 1 Poor gloss. 2. During the film-forming process, water is sucked in and turns white. 3. The ink is rough. 4. The ink dries too fast. 5. The resin composition of the ink system is small or the matting agent is added by mistake. In high temperature and humidity in summer, especially in coastal areas, the ink absorbs moisture in the air during the printing process and damages the oiliness, thereby reducing the gloss. Troubleshooting: 1 An appropriate amount of 3% - 5% cyclohexanone or 2% - 4% ether is added to the ink to resist the invasion of water molecules. 2. Regrind or filter the ink. 3. Use slow drying solvent to supplement the ink system. 4. Add an appropriate amount of 5% - 15% resin solution into the ink bucket. 5. Do not add or add less matting agents (such as wax, white carbon black, etc.). 6. Replace the ink with good gloss or dilute it with less solvent. G (author: Zhejiang Fukang company) ◎ common problems faced by many new material enterprises in the development process 1

how to improve the quality of coated paper printing? 16: Coated paper is an important material for packaging and decoration printing process. The printing quality of its products depends largely on the quality of the material itself and the degree to which the operator knows the characteristics of the paper. In other words, to print coated paper products well, corresponding technological measures must be taken according to the characteristics of the paper. Therefore, it is necessary to know and understand the process and technical requirements of printing coated paper

the varieties of coated paper are generally divided into single-sided light and double-sided light according to the difference between filling and calendering. From the nature of the coating, it can be divided into casein coating. So coated paper is also called coated paper. Due to the defects in the process of some domestic coated paper, it is easy to produce different degrees of de powdering and stretching variation, especially the single-sided coated paper is prone to curl, which affects the accuracy of overprint. If the process operation of printing coated paper is improper, it is also easy to produce sticky dirt (over bottom), chalking, slow drying, Star color is not bright, etc., so we should pay attention to the following problems

1. Before each batch of coated paper is put into use, a series of printing suitability problems involving smoothness, pH, absorption, dryness, scalability and surface bonding strength of the paper should be tested and analyzed, and then corresponding process measures should be taken according to the characteristics of the paper, such as adjusting the viscosity, fluidity, dryness and anti sticking measures of the ink, so as to realize standardized scientific production, Prevent printing defects

2. It is necessary to check the pad technology and printing pressure adjustment to ensure that the printing ink layer is uniform and bright. The printing pressure of coated paper should be uniform and appropriate. Excessive pressure is easy to produce poor powder dropping, and it is easy to cause unclear dot marks, as well as increase the wear of the printing plate. On the contrary, it is easy to cause weak dot imprinting and blindly increase the ink layer to make up for the blooming of the layout caused by insufficient pressure. In that way, it is easy to produce sticky dirt, slow drying, poor overprint and other adverse consequences. Therefore, the pressure of printing coated paper should be uniform and appropriate. The lining should be made of neutral and hard materials

3. Use coated paper to print trademarks and packaging products, often with light color as the background color, which is made by overlapping and overprinting. In this way, if the printing process is improper, it is also easy to produce some problems and affect the quality. Therefore, when allocating the base color ink, we should try to choose heat-resistant and light-resistant ink, and the diluent is best allocated with bright paste. In this way, the base color can be put into the final printing effect, so as to prevent the base color from rubbing and damaging the ink layer

4. Due to the smooth surface of copper plate and poor ink absorption ability, when printing the field version of large layout, It should be done as much as possible "Deep ink and thin firefly. That is to say, the ink phase should be appropriately deepened, so that the ink layer can be correspondingly or thinner during printing, which can not only meet the requirements of printing hue, but also reduce the chance of over bottom imprinting, and prevent color stacking printing. In addition, due to the poor adhesion of the paper, the printed ink layer is sometimes prone to discoloration due to powder dropping. Therefore, No. 19 resin oil can be used as the ink mixing oil for printing the first color. In order to make the color stacking ink layer bright, it can be suitable in the ink Add some light oil and dry oil

5. Due to the large amount of coating, coated paper often encounters the phenomenon of de dusting and dark shadow on the printed page during the printing process. In this case, you should pay attention to check whether the plate loading process is operated, such as whether the printing plate is padded too heavily, because if the paper surface pressure is too large, it is easy to crush the coating powder on the surface of the coated paper, resulting in de powdering and dark spots. In addition, it is also necessary to check whether the viscosity of the ink is appropriate. If the printing ink layer is too thick and sticky, it is also one of the reasons for the powder falling off the paper and stacking the layout. In this case, it is necessary to consider the application of auxiliary materials to adjust the quality of the ink, and the above quality problems can be better overcome

6. The anti sticking technology of coated paper printing should be well controlled. The ink absorption of coated paper is weak, and the back is relatively smooth. In this way, the printing of the layout with a large amount of ink or multi-color overprint is easy to produce the problem of stickiness and dirt, so anti stickiness measures should be taken to overcome it. For example, a proper amount of anti stickiness agent should be stirred with gloss oil to make it liquid, then added to the oil and ink, and then stirred evenly. A better anti stickiness effect can be obtained during printing. However, the amount of anti adhesion agent should be reasonably controlled, which should not exceed 4%, so as to avoid adverse disadvantages such as ink emulsification, printing ink layer blooming and ink layer gloss reduction

in a word, as long as we master its characteristics and correctly control the printing and operation technology, we can not only improve the printing efficiency, but also effectively ensure the printing quality

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