Hyaluronic Acid Breast Enhancement Injection Shijiazhuang Asa Technology Co., Ltd. , https://www.hskinlift.com
First, close the tight
Overtight winding will directly lead to a decrease in the transparency and gloss of the film. This is mainly due to overtight winding, which causes almost no air to remain between each layer of film and mechanical interlocking of “uneven†coatings. A form of blocking - when the roll is unwound, this fit is separated, thus destroying the smoothness and cleanliness of the surface, resulting in reduced gloss and increased haze. The over-tightening of the film directly indicates that the inside of the film roll is yellow, and even the film roll surface is oily yellow.
the reason:
1The winding tension is too large, because the coating just finished is soft and has a little stickiness. If the tension is too large, it may cause the film to adhere; 2 the winding tension attenuation is too small, the tension attenuation is the tension In the process of winding, there is a big change; 3 the pressure of the winding roller is large; 4 the drying temperature of the oven is too high, the substrate is seriously deformed, and a large amount of shrinkage occurs during curing to make the film roll tight; 5 the oven section When the base film is subjected to too much tension, it will produce a relatively large amount of shrinkage when it is significantly elongated and solidified, and the film roll will become tight. 6 The width and thickness of the base film have become narrower and thinner, and the drying section tension and shrinkage have occurred. Roll tension is not adjusted accordingly. 7 The coating amount has been adjusted greatly, and the drying temperature has not been changed accordingly. 8 The temperature of the curing chamber is too high, for example, >45°C, causing the coating to stick.
The countermeasures adopted are generally:
1 Adjust the volume tension value to a reasonable area. 2 properly increase the attenuation of tension. 3 properly reduce the pressure roller pressure. 4 Lower the drying temperature so that the surface temperature of the coated film reaches 85-90°C, but it must be ensured that it is sufficiently dry. This can be judged by examining the glossiness of the film haze. 5 Reduce the film tension of the oven section. The tension is about 50N/m, but it must be avoided. 6 Adjust the corresponding control tension. 7 The coating amount changes, and the corresponding drying temperature must be changed. 8 pay attention to the change of the curing chamber temperature, the temperature is controlled at 35-40 °C, do not adjust the steam opening degree to the limit.
Second, coating haze
The haze of the film is haze, which is caused by the coating surface and coating interface defects and the unevenness inside the coating. The low haze transparent film produces a clear, glossy package appearance.
There are many causes for the haze of the coating film, but all can find and find the cause from the surface, interface defects and coating unevenness, so as to reduce the haze. Among the many factors, the most influential, but often the reason is that the winding is too tight, so that the surface when the unwinding micro-tear, or pull the hair, followed by a large amount of formula SIO2 or face coating SIO2 will be enriched Significantly increased haze, thus avoiding the use of large amounts of SIO2 in the formulation and enhancing the surface coating agitation.
There are two types of causes of haze: surface interface defects and uneven internal coating.
1. The causes of surface interface defects are generally analyzed as follows: 1 The surface tension of the base film is unevenly distributed or the surface tension value is insufficient, because in the multilayer coating, the upper layer must be able to spread on the lower layer, so the surface tension of the upper layer in all coatings Must be smaller than the lower layer. 2 Dirty rollers cause the base film to wear. 3 The primer coating is uneven. 4 The primer is not dry enough and there is a trace of moisture or solvent remaining in the primer coating. The drying process of the coating is usually a thermal process that provides thermal energy to the fluid coating to evaporate the solvent. 5 The condensation on the surface of the chill roll after the primer coating draws moisture from the coated surface of the primer. Five-sided coating is uneven. The 7-coating coating is scratched or worn. 8 The coating is slightly torn when the roll is wound tightly.
The general countermeasures for surface interface defects are: 1 Check surface tension and increase corona treatment power. When using a solvent-based primer, it is generally required that the surface tension of the treated BOPP be ≥38 dyn/cm, whereas when using a self-adhesive PVDC as the primer, ≥42 dyn/cm is required to achieve good wetting and coating effects. 2 Clean the guide roller surface and check if the guide roller operation is flexible. 3 Adjust related parameters such as coating roll angle, a-roller moment, base film tension or coating roller to produce blockage. 4 Check coating drying temperature, oven circulation air volume. 5 Turn off the cooling water flow. 6 Adjust related parameters such as coating roll angle, a-roller moment, base film tension, or coating roller to produce blockage. 7 Check if the guide rollers and other surfaces are clean and operate flexibly. 8 Avoid over-tightening.
2. The general causes of non-uniform internal coating are: 1SIO2 distribution is not uniform. 2 Insufficient drying, partial moisture or residual solvent caused by uneven areas.
The general countermeasures for the non-uniformity of the interior of the coating are as follows: (1) Strengthen the filtration of SIO2 dispersion and strengthen the stirring of the top coating. 2 Increase the temperature or increase the amount of circulating air. Let dry enough.
Third, coating lines
The coating line produces a coating line on the surface of the coating film. This is a coating thickness on the line that is much larger than the coating thickness at other locations and leaves a line after drying. In severe cases, the line cannot be completely dried and milky. , And violence, seriously affecting product quality.
The reason for coating lines is:
1. Coated roll holes are blocked, ie blocked. The reasons for blockage may be: relatively high temperature of chilled water; high temperature of the film itself; insufficient drying of the primer to cause surface coating; after the stoppage, the roller does not rotate or shut down and is not cleaned immediately; the latex is in the coating process. Demulsification.
2. The blade has a slight gap.
3. The squeegee has a "burr", which refers to a matte finish existing on the new squeegee, or a dry coating on the squeegee after use.
4. There are solid particles between the doctor blade and the applicator roller. Solid particles mainly come from the SIO2 micropowder that is not completely dispersed.
5. The coating itself is dirty.
Coating line generally taken measures:
1. Solve the blockage: Close the valve opening of the small frozen water; observe the cooling effect of the press roll before coating; do not open the large cold water flow under the premise of no condensation; fully dry the primer; must strictly implement the coating after shutdown Roller cleaning procedure and inspection with a 200x magnifier; analysis of the cause of demulsification.
2. Check the scraper carefully (using a 30x magnifying glass). If the notch is first polished with metallurgical sand, the scraper will be updated if the notch is not removed.
3. Carefully use the “Double Zero†gold sandpaper to carefully (injury the fingers) and carefully grind the blade;
4. Fold down the applicator, clean the applicator roller and applicator and applicator and doctor blade, and lengthen the strict sieve filtration of SIO2 liquid shear dispersion time;
5. Replace the filter and clean the filter.
IV coating coating
There are two kinds of coating leakage coating: the primer before the primer coating causes primer coating and surface coating leakage.
1. Causes of primer coating before base coating caused by primer coating leakage analysis: 1 substrate surface tension is small, the friction coefficient is small; 2 base film uniformity is poor; 3a roller wrapped rubber dirty, or aging loses elasticity; 4a roller drive friction plate failure 5a roller drive friction is too small; 6 oven section tension setting is too small; 7 primer at the guide roller is not parallel.
The general countermeasures for base coat leakage caused by substrate shake prior to priming:
1 Test surface tension, contact a roller should generally ≥38dyne/cm, friction coefficient is best ≥ 0.4 (moving and static); 2 improve the quality of the base film; 3 clean, clean rubber or use new rubber; 4 change with a new friction Film; 5 increase a roller drive friction cylinder, air pressure; 6 reasonable setting oven tension is generally 55-80N / m better; 7 appropriate leveling of the guide roller.
2. Analysis of the reason why the surface coating is missing: The surface coating may be classified as the cause of tension and the cause of the basement membrane.
Topcoat coating must be under sufficient tension so that it does not leak. Therefore: a roller drive friction is not enough; a roller surface wrapped plastic dirty or aging loses weak; oven tension is not enough.
Countermeasures: Increase the pressure of the a roller-driven friction cylinder; clean and clean the rollers wrapped in the a roller, and replace it if necessary; properly adjust the tension of the top coating drying tunnel. Generally, the ideal tension value is 55-80N/m, excessive tension. Distortion of the base film seriously affects the flatness and rolling quality of the film
Base film causes: base film surface tension <38dyne/cm, coefficient of friction <0.4; poor uniformity; poor heat resistance, wrinkles due to severe shrinkage due to the base coat drying; excessive base film tension and base film , deformation, wrinkles; bottom coating oven fan block is too high, that is, the wind blowing on the surface of the base film over the ambassador base film to produce longitudinal wrinkles.
Countermeasures: Observe if the tension of the primer oven is too large; adjust the throttle inside the oven so that the base film does not produce wrinkles.
Don't: When the temperature of the bottom coating oven fluctuates greatly, it will cause the top coat to leak. The pressure of a pair of pressure rolls before coating or the surface of the pressure roll is not smooth will cause the tension not to be effectively segmented, that is, the tension †And out of control caused the bottom, coating smear; coating roller speed and the speed of the machine does not match, resulting in paint leakage.
Countermeasures: Observe the oven temperature value and curve change, especially the bottom coating oven, wait until the oven temperature is basically stable before starting the machine; adjust the surface of the high pressure roller; the better speed ratio is V-roller/V machine 1.0-1.2.
In actual production, different equipment and environment will cause different results. The corresponding solution should be selected according to the actual situation.
Causes and Countermeasures of Common Defects in PVDC Coating Process
PVDC has a very comprehensive protective performance as a packaging material. It has outstanding water vapor barrier properties, significant gas barrier properties, and fragrance retention and protection. This superior performance of PVDC packaging materials is increasingly accepted by everyone. As the PVDC coating process is a new product with high technical content and great technical difficulty, the coating process is prone to some quality defects. The poor resolution of these defects will affect the appearance of the product and its performance, and solving these quality defects is also a measure of the enterprise. Technical level, equipment status main signs. The quality defects that are likely to occur in the PVDC coating process include: over-tightening, coating haze, coating lines, coating leak coating, and the like.
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