Cellophane and composite film printing account for a large proportion. Especially in the food, beverage, daily chemical, pharmaceutical flexible packaging and other industries more widely used. Having a beautifully printed and innovative packaging will undoubtedly win consumers more favor. However, such outer packaging may cause the ink layer to fall off due to transportation friction, handling, and placement time, which may affect the overall appearance. Consumers may think that it is a “counterfeit and shoddy†product, resist buying, or even complain. As a result, the credibility of manufacturing companies is seriously damaged. Many manufacturers also have a lot of confusion about the resolution of similar problems. The following is a discussion of the quality control of the combination of ink layers and the printing industry.
First, the use of equipment
1. Adhesive tape roll press (for example, Jinan Languang equipment): 1 Roller covered with a rubber covered metal wheel with a diameter of 84:1mm and a width of 45mm. 2 The rubber hardness (Shaoer A type) is 60°-80° thickness 6mm. Rolling load 20 ± 0.5N. 4 Rolling speed 300mm/min.
2. Disk peeling tester (taking Jinan Languang equipment as an example): 1 The pressure between the disks is 100N. 2 Stripping speed 0.8m/s (GB 0.6-1.0m/s). 3A disk diameter φl70mm, width 55mm; B disk diameter (1> 65mm, width 55mm.
Second, the test conditions
1. Adhesive tapes meet the following requirements: 1 Width 20mm. 2 Adhesive force 3-4N/20mm. 3 tape substrate cellophane. 4 adhesive natural rubber. 5 Solvent aromatic hydrocarbons.
2. 20mm wide translucent mm paper.
Third, the test procedure
1. Take 250 × 30mm samples to be tested, pay attention to try to take the place where the ink color is even, in order to measure the result.
2. Stick the tape that meets the above requirements on the sample. The sample should be straight and wrinkle free to avoid air bubbles. (Recommended to use Shanghai Polar Bear Stationery Co., Ltd. "Polar Bear" brand tape).
3. Put the taped sample on the roller, start the test and roll it back and forth three times, remove the sample, and leave it for 5 minutes. This process allows the adhesive tape to adhere evenly to the sample, driving off the air bubbles.
4. The sample to be tested is pre-striped by 80 mm and the two ends are fixed on the A plate and the B plate, respectively. The test is started and the tape is separated from the sample.
5. Remove the sample and cover it with the width of 20mm mm paper. The number of cells occupied by the ink layer and the number of cells occupied by the peeled ink layer are counted. Calculated according to the following formula: ink layer bonding fastness=A1/(A1+A2)×100%. A1: the number of cells in the ink layer; A1 is the number of cells in the ink layer.
GB7707-87 stipulates that the ink layer bonding fastness ≥ 95% is a qualified product. This standard is not suitable for paper product mounting products. The user often encounters the following problems in the actual operation of the test:
1. After peeling, the specimen was torn and the test results could not be recorded. At this point we must consider the strength of the sample, the premise is that the tape strictly meets the requirements of the national standard.
2. The calculation of the test results is troublesome and all the stripped parts have to be calculated. In fact, according to experience, covering the most severely peeled places with millimeter paper, the 10×10 grid portion can be calculated.
3. No matter how carefully the sample is made, there will always be air bubbles between the adhesive tape and the sample, which will undoubtedly affect the test results. Actually, the adhesive tape is unevenly coated even though it meets the requirements (3 to 4N/20mm). It is advisable for companies with conditions to use a testing machine with a drawing device that automatically records the peeling load to screen the tape to minimize errors.
Although the country formulated this standard in 1987, the actual status quo in the printing and packaging industry is uneven. At the "2001 Shanghai China International Printing and Packaging Industry Exhibition", after seeing the disc peeling tester in the Jinan Languang booth, the Shanghai audience excitedly said, "The engineers of their companies have been sticking the tape to the sample by hand. , and then manually peeled open, judging the combination of ink fastness by experience, due to uneven adhesion, each peeling force is not the same, the comparability is not strong, it is difficult to control the quality, they are looking for such equipment ". There are certainly many companies like this. From another side, it also reflects that the manufacturers' propaganda is not enough. However, it is undeniable that many manufacturers do not pay attention to this quality indicator and think that sales can still be done. Customers do not have to complain. However, with China's accession to the WTO and the influx of foreign companies, printing and packaging companies have been unavoidably affected. Enhancing product competitiveness, controlling quality, and improving quality are top priorities. At present, many domestic companies, such as the Shanghai Toothpaste Factory, Shanghai Guoma, and Jiangsu Daya, have added such equipment and have obtained great economic benefits.
First, the use of equipment
1. Adhesive tape roll press (for example, Jinan Languang equipment): 1 Roller covered with a rubber covered metal wheel with a diameter of 84:1mm and a width of 45mm. 2 The rubber hardness (Shaoer A type) is 60°-80° thickness 6mm. Rolling load 20 ± 0.5N. 4 Rolling speed 300mm/min.
2. Disk peeling tester (taking Jinan Languang equipment as an example): 1 The pressure between the disks is 100N. 2 Stripping speed 0.8m/s (GB 0.6-1.0m/s). 3A disk diameter φl70mm, width 55mm; B disk diameter (1> 65mm, width 55mm.
Second, the test conditions
1. Adhesive tapes meet the following requirements: 1 Width 20mm. 2 Adhesive force 3-4N/20mm. 3 tape substrate cellophane. 4 adhesive natural rubber. 5 Solvent aromatic hydrocarbons.
2. 20mm wide translucent mm paper.
Third, the test procedure
1. Take 250 × 30mm samples to be tested, pay attention to try to take the place where the ink color is even, in order to measure the result.
2. Stick the tape that meets the above requirements on the sample. The sample should be straight and wrinkle free to avoid air bubbles. (Recommended to use Shanghai Polar Bear Stationery Co., Ltd. "Polar Bear" brand tape).
3. Put the taped sample on the roller, start the test and roll it back and forth three times, remove the sample, and leave it for 5 minutes. This process allows the adhesive tape to adhere evenly to the sample, driving off the air bubbles.
4. The sample to be tested is pre-striped by 80 mm and the two ends are fixed on the A plate and the B plate, respectively. The test is started and the tape is separated from the sample.
5. Remove the sample and cover it with the width of 20mm mm paper. The number of cells occupied by the ink layer and the number of cells occupied by the peeled ink layer are counted. Calculated according to the following formula: ink layer bonding fastness=A1/(A1+A2)×100%. A1: the number of cells in the ink layer; A1 is the number of cells in the ink layer.
GB7707-87 stipulates that the ink layer bonding fastness ≥ 95% is a qualified product. This standard is not suitable for paper product mounting products. The user often encounters the following problems in the actual operation of the test:
1. After peeling, the specimen was torn and the test results could not be recorded. At this point we must consider the strength of the sample, the premise is that the tape strictly meets the requirements of the national standard.
2. The calculation of the test results is troublesome and all the stripped parts have to be calculated. In fact, according to experience, covering the most severely peeled places with millimeter paper, the 10×10 grid portion can be calculated.
3. No matter how carefully the sample is made, there will always be air bubbles between the adhesive tape and the sample, which will undoubtedly affect the test results. Actually, the adhesive tape is unevenly coated even though it meets the requirements (3 to 4N/20mm). It is advisable for companies with conditions to use a testing machine with a drawing device that automatically records the peeling load to screen the tape to minimize errors.
Although the country formulated this standard in 1987, the actual status quo in the printing and packaging industry is uneven. At the "2001 Shanghai China International Printing and Packaging Industry Exhibition", after seeing the disc peeling tester in the Jinan Languang booth, the Shanghai audience excitedly said, "The engineers of their companies have been sticking the tape to the sample by hand. , and then manually peeled open, judging the combination of ink fastness by experience, due to uneven adhesion, each peeling force is not the same, the comparability is not strong, it is difficult to control the quality, they are looking for such equipment ". There are certainly many companies like this. From another side, it also reflects that the manufacturers' propaganda is not enough. However, it is undeniable that many manufacturers do not pay attention to this quality indicator and think that sales can still be done. Customers do not have to complain. However, with China's accession to the WTO and the influx of foreign companies, printing and packaging companies have been unavoidably affected. Enhancing product competitiveness, controlling quality, and improving quality are top priorities. At present, many domestic companies, such as the Shanghai Toothpaste Factory, Shanghai Guoma, and Jiangsu Daya, have added such equipment and have obtained great economic benefits.
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