Question and answer 4 of the hottest plastic packa

2022-09-23
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Q & A on plastic packaging printing and composite technology (IV)

24. What is the quality standard of gravure decoration printing

the main contents of the quality standard (GB) for intaglio decoration printing are as follows:

this standard is applicable to plastic film and cellophane decoration printing produced by intaglio printing process

(1) technical requirements. ① Appearance. The finished product is clean and tidy without obvious dirt, deformity and knife thread. The text shall be printed clearly and completely, and the meaning of words below No. 5 shall not be mistaken. The imprinted edge is smooth, the lines are clear and uniform, and there is no obvious deformation and deformity. ② Overprint error should comply with table 1:

overprint position limit deviation field printing main position ≤ 0.5 ≤ 0.3 secondary position ≤ 0.8 ≤ 0.6 field printing requirements should comply with table 2:

index name unit symbol index value same color density deviation - DS ≤ 0.06 same, but its implementation to the real place needs to be strengthened. The same color difference ciel*a*b* △ el*> 50.00l* ≤ 50.00 ≤ 6.00 ≤ 5.00 ink layer gloss%ds (60) ≥ 35 ink layer bonding fastness% - ≥ 95 (2) test method. ① Test requirements. The temperature of the laboratory is 23 ± 2 ℃. The relative humidity is 50% ± 5%. The sample shall be pretreated and placed in the environment without ultraviolet radiation for no less than 8 hours. Light source: D65 standard light source with color temperature of 5500 ~ 6500k, and the distance between the light source and the table top of the sample table is about 800mm. ② Appearance. Place the sample under the specified light source, and the distance between the observer's eyes and the visual part is about 800mm. Visual identification. ③ Overprint error. The light source is the same as ①. Instrument: 20 times scale microscope, with an accuracy of 0.01mm. Test steps: under the required light source, check the overprint error between the two colors of the main part and the secondary part of the sample, measure three points respectively, and take the average value as the overprint error of the main part and the secondary part respectively. ④ Homochromatic density deviation. Instrument: the reflective color densitometer with Leiden color filters No. 58, 47 and 25 and infrared color filters is adopted, and its accuracy is less than or equal to ± 0.02d. Use of color filter. If the measured color is black, white or gray, use infrared filter. The measured color is three primary colors, and the color filter is selected according to table 3. If the measured color is formed by matching two or more primary colors, the color filters listed in Table 3 should be selected respectively

select the color filter name code color magenta Leiden 58 C green yellow Leiden 47 B blue green Leiden 25 r red test steps: the background is white during the test. Select the color filter according to the measured color. Use a standard whiteboard calibration instrument to make the color density value equal to the specified value on the whiteboard, accurate to ± 0.01d. Each time you select a filter, calibrate it. The width of the finished product is less than or equal to 129mm × 184mm (32), measure 1 point at the four corners and the middle of the same color of the same sample; The width of the finished product is greater than 129mm × 184mm (32), evenly add 5 points on the same sample. ⑤ The same batch has the same color difference. Instrument: the integrating sphere color difference meter is adopted, and the tip meets the provisions in Chapter 3 of gb3979-83 "methods for measuring object color". The standard illuminant is D65, and the field of view for color measurement is 10 °. The data of cie1964 supplementary standard chromaticity observer "is adopted. The measured area is generally diameter φ 25mm round hole. If the measured part is small, a small observation hole is allowed, and its area shall not be less than 25mm2. Test steps: take the printed sample as the benchmark, first measure the l*a*b* value of ciel*a*b* uniform color space, and then measure the color difference between the sample and the part with the same color as the benchmark. ⑥ Gloss of ink layer. Instrument: the glossmeter should include a light source and a lens, which can project parallel rays or slightly convergent beams on the measured surface. The glossmeter also includes a receiver, which is equipped with a lens field grating and a photocell to receive the required reflected light cone. Its optical path is shown in Figure 144. Geometric conditions: the incident light is 60 ° ± 0.5 ° from the vertical line of the measured surface( θ)。 The axis of the receiver should coincide with the image of the axis of the incident light. If a piece of flat polished black glass is placed on the position of the test right, the image of the light source should fall on the center point of the field grating of the receiver, and the width of the light point where the test plate seriously hinders the infiltration of water and the underground water flow should not be less than 10mm. The angle between the axis and the vertical line of the receiver light( θ’) It should be equal to the incident light angle with the same corresponding deviation. Light source: CIE standard C light source or D65 light source is adopted. Instrument calibration: the working standard sample adopts ceramic tile, enamel, Matt glass and other turbulent and uniform materials, and the surface must be smooth. A glossometer must be equipped with a primary standard sample and a working standard sample. The sample must be calibrated regularly, and its working characteristics should be uniform and stable. At the beginning of each test stage and at a certain interval during the test, the glossometer should be calibrated to ensure that the response of the instrument is basically consistent. When approving, first adjust the zero point of the instrument, and then make it correctly display the gloss of the primary standard template with high gloss. Then put on the working standard board and read out the lower standard gloss. The difference between the reading and the value specified in the standard shall not exceed 1 gloss unit. Test steps: ① the sample must be flat and wrinkle free. ② Measure the surfaces of different color layers of the sample respectively. Measure three points within 100cm2 of the color area, and five points when the color area is greater than 100cm2. ③ When the gloss difference of each color measurement result of each sample is greater than 5 units, double the test point. Test results: calculate the average value of the same color gloss of the sample as the color gloss of the sample

test results. Cover the uncovered part with 20mm wide translucent mm grid paper. Count the number of cells occupied by the ink layer and the number of cells occupied by the removed ink layer respectively. Calculate according to the following formula:

a1

ink layer bonding fastness=—————— × 100%

a1 + A2

where: A1 - the number of cells of the ink layer, including specific actions such as green packaging, green distribution, green recycling, green intelligence, etc

a2 -- the number of cells of the removed ink layer

(3) inspection rules. ① If the production conditions are basically the same, a group of unit products of the same variety and delivered at the same time are a batch. ② The sampling quantity of each batch is generally 5 pieces. ③ Unqualified judgment: each product is determined according to the test method. The required technologies refer to the aluminum alloy cable industry and market will also enter the stage of vigorous development. If one or more technical indicators fail to meet the requirements, the product is unqualified. ④ Judgment of unqualified batch: each batch of products shall be sampled and inspected according to the sampling table or stratified sampling method. If one or more of them are unqualified products, double sampling and retesting shall be carried out. If one or more pieces are still unqualified, the batch is unqualified

(4) marking, packaging, transportation and storage. ① Mark: there should be a qualified label on the horizontal head of each package, indicating the user unit, product name, variety, specification, quantity, manufacturer name, ex factory date and inspector code. ② Packaging: according to the user's requirements or the volume or quantity of products, use stronger packaging paper to pack and bind. ③ Transportation: it is not allowed to throw, smash or step during transportation. Pay attention to moisture-proof, rain proof, sun proof, hot baking, heavy pressure proof and corrosion-resistant gas and liquid. ④ Storage: the storage environment requires moisture-proof, sun proof, oil proof, mildew proof, corrosion-resistant gas and liquid, and can not be heavily pressed. The storage period is generally six months

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