Research on Synchronous Glazing and Bronzing Based on Dry Offset Printing Process
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In the company, after investigation and research, it was found that in the production process of caps, the aluminum cylinders printed by dry offset printing had higher scrap rate and process waste in the glazing and bronzing process. In order to improve the production status, reduce the scrap rate in the production process, save the process, increase the production capacity, decided to use the "dry offset and gilding process based on dry offset printing" as the project topic, using the professional knowledge, experimental analysis, material verification and Small batch production and other methods, based on the performance index of varnish, the apparent characteristics of the surface of the printed product after glazing, and the apparent characteristics of the surface of the printed product after bronzing, can be obtained between the synchronous glazing oil and the hot stamping paper. The matching relationship provides the basis for the selection of synchronous glazing oil and hot stamping paper in the future.
This research project is aimed at the post-press processing of caps, glazing and bronzing. The highlight of this study is that the matching relationship between the glazing varnish and the gilding paper can be obtained, and the corresponding standard is developed to provide the basis for the later selection of the synchronous glazing oil and the gilding paper, thereby realizing the dry offset printing and glazing. Synchronous implementation, and solve the problem of high scrap rate after hot glazing.
First, the actual production encountered problems and the proposed experimental plan
In the actual production process, the roll printing, roller light and bronzing process encounter a series of problems that need to be solved.
Problems encountered when synchronizing glazing: When producing caps, some products require side roller light, and the glazing method is mainly synchronous glazing. The problems encountered during the period are mainly horizontal stripes and blurred graphics, and corresponding problems occur. The main reason is that the varnish is compatible with the roller printing ink. In addition, there are also varnish coatings that burst, peel, and fall off. The main cause of the problem is the excessive hardness of the varnish.
Synchronized glazing products encountered problems when gilding: products that need side glazing and bronzing. After synchronous glazing, the problem that tends to occur during bronzing is that it is not hot or hot. The main reason is the attachment of varnish layer. If you don't work well, you need to choose the right bronzing paper. Secondly, it is hot, mainly caused by excessive temperature, uneven surface of the bottle cap and excessive pressure. In addition, there are also gold, mainly because the paper is too loose, and the temperature is too high. In addition to this, there will be a phenomenon of flying gold foam, mainly due to the poor quality of hot stamping paper.
Generally, the quality inspection department of the quality inspection department will test according to the requirements of the national standard.
Experimental scheme: Match the existing varnish with bronzing paper, and test about 60 caps in each group. Observe the test results and measure and analyze the apparent characteristics of the cap surface to obtain synchronous varnish and bronzing. The apparent characteristics of the matching group with good matching between papers provide the basis for the selection of synchronous glazing oil and hot stamping paper for future production.
Second, the test and results
In order to obtain the matching relationship between the glazing varnish and the bronzing paper, and to develop corresponding standards, it provides the basis for the selection of synchronous glazing oil and hot stamping paper for future production.
1. Experimental steps
1 Rolling the aluminum cylinder by the roll printing process.
2 The aluminum cylinders after glazing are measured and analyzed according to the apparent characteristics listed in the table below.
3 The glazed aluminum cylinder is bronzing at 240 ° C - 270 ° C using a fully automatic three-color hot stamping (silver printing) machine.
4 The bronzing aluminum cylinders were measured and analyzed according to the apparent characteristics listed in the table below.
5 According to the corresponding analytical values, the corresponding standards are determined.
The materials used in the experiment are: 5033 varnish, 3003 varnish, Huadi Di 6041 varnish, Zibo Kainuo k-308 varnish, four kinds of glazing oil, K70-220 gilding paper, BC-220G hot stamping paper, 398-220 Bronzing paper three kinds of gold foil paper, 800 washed aluminum cylinders.
The instruments used in the experiment are: four-color roller printer and fully automatic three-color hot stamping (silk screen) machine.
The preparation work before the experiment is as follows:
The glazing oil used for testing and production is mainly 5033 varnish, 3003 varnish, gorgeous di 6041 varnish, and Zibo Keno k-308 varnish.
2. Measurement of performance index of hot stamping paper used for testing and production
Generally, the anodized aluminum is checked by visual inspection and hand feeling, and the color, brightness and blisters of the anodized aluminum are checked. The fastness and tightness of the bronzing paper are generally adhered by hand or by a transparent tape, and the less the end of the anodized aluminum, the better.
The technical quality of electrochemical aluminum foil has the following requirements:
1 The bottom layer is evenly painted, with no obvious color difference, color bars and stains.
2 The primer coating is uniform, smooth, white and free of impurities, no obvious streaks, sand spots and oxidation.
3 glossiness, when the printing plate temperature is 70 ~ 90 ° C hot stamping, the packaging color does not change.
4 fastness, rubbed by 100g weight, the number of wear resistance is required to be 2000-3000 times.
5 clarity, with the fourth word hot stamping, clear strokes and no sticking is reasonable.
3. Data measurement method
1 gloss measurement method.
Gloss is the degree of reflection of light on the surface of the paint film. The standard plate gloss is taken as 100% during the test. The measured paint film is compared with the standard plate and expressed as a percentage. There are many factors that affect the gloss of the coating film. Through the inspection of this project, it is possible to know whether the resin used in the coating product, the pigment filler, and the ratio of the resin are appropriate. The measurement of gloss basically uses two major instruments, namely photoelectric photometer and projection gloss meter. The former is used in this experiment.
2 Surface hardness measurement method.
The film hardness pencil method is used in the production. The coating film hardness pencil method is a method of measuring the hardness of a coating film by using a pencil with a known hardness number to scratch the coating film. According to industry standards, the hardness of pencil refills is divided into 13 grades. From the hardest 6H step by step, through 5H, 4H, 3H, 2H, H, then through the soft and moderate HB, then from the B to the softest 6B. This is a scientific hardness system with a defined hardness value. In the coatings industry, this series of different hardness pencils is used to test the hardness of the coating film, and the test result is called the pencil hardness of the coating film.
3 adhesion determination method.
Determination of adhesion of glazing products:
The aluminum cover can be visually tested after sealing test; after the aluminum plastic cover is pressed according to the finished product, the appropriate force is applied to the teeth of the roller with the nail (to prevent deformation of the cover), visual inspection after scratch test, and observation of waste Rate (nails can't be sharp nails just trimmed).
Bronzing product adhesion measurement:
Soak in 45 ° warm water, 50 ° white wine for 10 minutes, dry naturally, use a clean soft cloth in the same position, rub back and forth 6 times, observe the rejection rate (special requirements products must be soaked in 50 ° liquor for 10 minutes, Immediately use your thumb, rub 5 times on the bronzing pattern or gently scrape 2 times with a nail scraper to see if you drop the pattern and observe the color of the wine. If the pattern and the color change of the wine body do not appear, it is a good product).
4 coating film leveling method.
The four varnishes used in the test were smeared on the varnished aluminum plate and marked. Each varnish was scraped with two aluminum plates and dried in an oven. After 10 minutes, the surface of each surface was taken out. Performance, and comparative analysis, draw the corresponding conclusions.
4. Test results
Through the experiment, the final four varnishes after the blade surface gloss measurement data (three groups of each varnish measurement, and then averaged) can get the following data:
1 Gloss: Three aluminum cylinders were randomly selected, and the first group, the second group and the third group were respectively measured for their glossiness. Each group was measured three times for average, then the three groups were averaged again, and the values were recorded below. form.
Table 3 Surface gloss
2 Surface hardness: Three aluminum cylinders were randomly taken and the surface hardness was measured separately. The values are recorded in the table below.
Table 4 Surface hardness
3 other apparent characteristics and scrap rate after glazing:
Table 5 Other apparent characteristics
After that, bronzing is performed, and the apparent characteristics of the side of the cap after bronzing are recorded as follows:
4 Use BC-220G hot stamping paper.
Apparent performance:
Table 6 Apparent characteristics
5 Use K70-220 hot stamping paper.
Apparent performance:
Table 7 Apparent characteristics
6 Use 398-220 hot stamping paper.
Apparent performance:
Table 8 Apparent characteristics
Third, the conclusion
Through a series of tests of simultaneous glazing and bronzing, the matching relationship between the four test simultaneous glazing oils and three kinds of hot stamping papers was obtained:
1.5033 varnish synchronous glazing effect is good, the picture is not blurred; after rolling, the varnish does not have skin, the adhesion is good; there is no leakage phenomenon in matching with three kinds of gilding paper; the adhesion detection is soaked with 50 degree white wine After 10 minutes, naturally dry and wipe with a clean soft cloth at the same position for 6 times, and pass.
The test proves that the matching relationship between 5033 varnish and bronzing paper meets the requirements of simultaneous glazing and bronzing.
2.3003 varnish synchronous glazing effect is good, the picture is not blurred; there is no leakage phenomenon when matching the three kinds of hot stamping paper; when the adhesion is detected, soak it with 50 degree white wine for 10 minutes, naturally dry and use a clean soft cloth in the same The position is wiped back and forth 6 times and passed.
3. Ramada Di 6041 varnish has good glazing effect, no blurry picture; after rolling, varnish does not have skin, good adhesion; match with three kinds of hot stamping paper, all hot foil, hot stamping paper attached to varnish surface The effort is extremely poor and the bronzing is unqualified.
The test proves that the Huadi Di 6041 varnish meets the quality requirements of synchronous glazing, but it does not meet the requirements of bronzing. The matching relationship between Huameidi 6041 varnish and hot stamping paper does not meet the requirements of simultaneous glazing and bronzing.
4. Zibo Keno K-308 varnish synchronous glazing scrap rate is higher, there is graphic blur phenomenon, synchronous glazing effect is not good; with three kinds of gold foil paper matching hot stamping, leaking hot, hot stamping paper attached to varnish surface The effort is extremely poor and the bronzing is unqualified.
The test proves that Zibo Keno K-308 varnish has the same effect of synchronous glazing, with graphic blurring phenomenon, which does not meet the requirements of synchronous glazing quality; it matches hot stamping with three kinds of gilding paper, and the leakage is severe, and the adhesion of gilding paper on varnish surface Very poor, bronzing is not qualified.
Through a series of tests and analytical studies, it is concluded that the products that can be used for simultaneous glazing and bronzing after dry offset printing use varnish and hot stamping paper to meet the following criteria:
5. Varnish
6. Gold foil paper
In this paper, the apparent characteristics of the matching effect between synchronous varnish and hot stamping paper are obtained through specific experiments, and the corresponding standards are obtained based on this data. However, since the company's equipment for production practice is different from the experimental equipment used for research, the conclusions still need to be verified in future production practices.