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At present, the use of blister packs for pharmaceutical tablets and capsules is becoming more and more common. Pharmaceutical blister packs, also known as PTP (Press Through Pack aging), are based on industrial pure aluminum foils. On the PTP aluminum foil applicator for pharmaceutical use, gravure printing techniques and roll coating methods are used to print text patterns on aluminum foils. Coated with a protective agent and coated with adhesive layer on the other side of the aluminum foil. The brief process flow is: aluminum foil unwinding → gravure printing → drying → coating protective layer → drying → coating adhesive layer → drying → aluminum foil winding. In the entire production process, the surface quality of the gravure printing text pattern and the heat sealing strength to be achieved by the adhesive layer and the quality control during the coating operation are needed to be grasped in the process operation. Therefore, this paper analyzes the factors affecting the heat-sealing strength and coating amount of aluminum foil, and describes the coating amount of aluminum foil and the detection method of finished product packaging. The purpose is to ensure that the product has a higher pass rate.
First, the factors affecting the amount of aluminum foil coating 1, the number of coated anilox roller screen, network depth and shape of the majority of aluminum foil coating equipment used anilox roller coating device, it is known as the texture coating method. The anilox roller is composed of a net hole and a net wall. The pit on the roller is usually called a net hole, and the high part is called a net wall or a network cable. After processing, the anilox roller is coated with a hard chrome with a thickness of 0.015 to 0.02 mm to increase the surface hardness of the anilox roller. The hardness value is H RC62-65.
When coating with an aluminum foil coating device, the working principle of the anilox roller is as follows: when the adhesive fills the anilox roller, the anilox roller rotates, and when the cell hole leaves the adhesive liquid surface, the roller The liquid at the smooth surface is scraped off with a scraper, leaving only the liquid that cannot be scratched in the cell, and the liquid (binder) is then brought into contact with the surface of the coated aluminum foil substrate. This contact is achieved by the action of a resilient rubber roller so that a portion of the binder solution in the cell is transferred to the surface of the aluminum foil substrate. Due to the fluidity of the adhesive, it slowly and automatically flattens on the surface of the foil, turning the original discontinuous liquid into a continuous, uniform liquid layer. A portion of the liquid in the anilox roller cell is transferred to the aluminum foil, while the anilox roller is rotating at the same time. Once it is rotated, it will be re-immersed in the adhesive liquid, and the liquid adhesive will fill the net hole again. , so that the cycle begins again and again. An anilox roller with a small diameter can continuously and uniformly transfer the adhesive solution to the aluminum foil substrate continuously, so that the surface of the aluminum foil can be uniformly coated with the adhesive. Obviously, if there are fewer network lines per unit area on the anilox roller, the deeper the cells, the greater the amount of coating; when the number of anilox roller lines is higher, the cells are shallower, and the filled adhesive is less. The coating amount is relatively small. In addition, the cell shape of the anilox roll is different, and its coating amount is not equal. For example, a 200 pyramidal anilox roller, ie, 200 cells per inch, approximately 8 cells per mm, has an adhesive storage capacity of about 0.5 pounds per square inch, ie 24 grams per square meter. With 24 triangular threads, the adhesive stock is up to 13 pounds per square foot, which is 63 grams per square meter.
2. Concentration and Density of Adhesive Solution For the anilox roller that has been made during the production process, the depth of the cell depth and the number of reticulate lines have been fixed, and the shape of the cell site can no longer be changed. Under these conditions, the amount of coating depends on the concentration and density of the binder formulation. We know that the coating amount is the mass (grams) of dry film bonded solid material per square meter of aluminum foil substrate area, so the adhesive solution has a high solids content and is applied to an aluminum foil substrate and the dry film is adhered. There are many solid materials, and the amount of coating is large. Thus, the relationship between the coating amount and the binder concentration and density and the depth of the cell is: the coating amount is proportional to the depth of the cell and the concentration and density of the binder.
If the depth of the cell depth of the anilox roller is fixed in the actual production operation, the coating amount has a great relationship with the concentration and density of the binder liquid, that is, the coating amount is determined by the concentration and density of the liquid. Decision. In contrast, if the binder concentration and density are determined, the amount of adhesive applied is determined by the depth of the anilox roller pocket.
3. The hardness and pressure of the rubber pressure roller in the coating device When the depth of the cell and the concentration and density of the adhesive are determined, the coating amount of the anilox roller is also affected by the hardness and pressure of the rubber roller in the coating device. It is the pressure on the left and right sides of the rubber roller. This requires that in the manufacture of rubber roller, the mixing of the rubber should be uniform, and the vulcanization conditions should be strictly controlled to ensure that the hardness of the rubber roller is uniform. If the rubber roller used is very soft, elastic, and the pressure on the roller is large, the amount of coating is reduced.
This is because the rubber roller squeezes into the cell of the anilox roller under a heavy pressure and deepens the adhesive solution, thereby reducing the amount of adhesive applied. In actual operation, the pressure of the rubber roller on the anilox roller should be controlled within the range of 2-3M Pa.
4. Application of scraper in coating device 1 Squeegee pressure. At present, the methods for adjusting the blade pressure device in the device include: tension spring pressure regulation, hand wheel pressure regulation, cylinder pressure regulation and pressure hammer pressure regulation. During coating, if the pressure applied by the doctor blade on the anilox roller is small, even when the pressure is not tight or there are mechanical impurities, the blade will be topped up to cause a gap, so that the coating is uneven and the amount of coating is increased. The factors that affect the blade pressure are: different hard and soft blades, different angles between the blade and the anilox roller. In actual operation, the hammer adjustment blade is taken as an example. The blade pressure is generally about 200-400KPa.
2 blade angle. The angle between the squeegee and the tangent of the anilox roller contact is generally between 15-30 degrees. If the angle is too large, the squeegee is almost against the stencil roller, and the surface of the cable is not smooth. When it rotates at a high speed, it will The elastic blade is caused to vibrate or bouncing, causing the solution to be bouncing up, resulting in non-uniform coating amount and causing a large difference in coating amount. In addition, too large an angle can easily damage the blade.
3 blade sharpness. The sharpness of the scraper mainly depends on the angle of blade wear and the purity of the solution and the quality of the knife. If it is a new knife, the sharpness of the knife should effectively scrape the adhesive layer on the anilox roller without producing a knife. Moderate sharpness of the knife can effectively scrape off the solution layer, resulting in a uniform coating amount. On the contrary, it causes the difference in coating amount to become larger.
5 blade flatness. Scraper flatness is good, does not produce warping, should be completed twice or three times in the screw tightening, should be screwed side, while holding the piece of cloth to grip the blade and the lining, and forced to one side tension. The knife installed in this way is relatively flat to ensure that the difference in the amount of coating is within the standard range.
5 blade left and right movements. The left and right movement of the scraper has an important effect on reducing the scraping line, increasing the scraper utilization rate, and reducing the wear of the anilox roller. From this point of view, the net wall wear is small, the net hole is relatively deep, and more liquid parts are contained, which is beneficial to The required amount of coating is achieved.
Second, the amount of aluminum foil coating and finished product heat seal strength detection and analysis 1, the measurement method First take the same thickness of aluminum foil, the size of 100 × 100 mm square sample, and said that its quality is W1. Then, normal coating was performed on the machine. After the coating was dried, the sample was removed and the dried mass was weighed to be W2. Then put it in a constant temperature oven at 105°C for 1 hour, remove it, cool it to room temperature in a desiccator, and finally weigh the thoroughly dried sample to a mass of W3. The formula for the coating amount is: coating amount = (W 3-W 1)/0.1 × 0.1 (g/m 2).
2, aluminum foil and PVC film heat seal strength measurement.
After the coated aluminum foil is heat-sealed with a polyvinyl chloride (PVC) hard sheet, the degree of adhesion between the two after heat-sealing is usually measured by the heat-sealing strength of the adhesive layer. The specific measuring apparatus is a tensile testing machine, a lever type Heat sealer, standard test piece cutter.
1 Sampling: Cut two 100mm×100mm test pieces in the finished aluminum foil, and cut 2 pieces of 100mm×100mm test pieces of pharmaceutical PVC hard films that meet GB5663.
2 heat sealing conditions: the heat sealer temperature is 150 °C ~ 160 °C, the pressure is 0.2 × 10 4 Pa, time is 1 second.
3 Operation: Laminate the adhesion layer of aluminum foil sample to PVC, insert a heat sealer for heat sealing, and use a standard cutter to cut a 15 mm wide specimen. Take the middle three specimens and test on a tensile tester. The test method is to adjust the tension tester first, and make the pointer of the recorder zero, set the tensile speed to 200mm/min, clamp the PVC in the sample on the tester, and clamp the aluminum foil under the tester. , Start the tensile tester to peel off at an angle of 180°. The test data is calculated as the heat seal strength value of PVC and aluminum foil (N/15mm), which can be calculated according to the formula Q=P/b. Where P is the sample peel force (N), b is the sample width (mm), and Q is the heat seal strength value (N/15mm).
3, the use of tensile testing machine to determine the heat seal strength test factor analysis 1 bonding area: PVC and aluminum foil heat seal strength are expressed in terms of the tension on the unit area. In the test, the size of the bonding area has a certain influence on the bonding strength. If the bonding area is too small, the sample preparation is not easy to be accurate, and the relative error of the bonding measurement is also large. As the bonding area increases, the probability of defects appearing on the bonding surface also increases. Therefore, when the heat-sealing strength is measured, specimens shall be prepared according to the width and length required by the standard.
2 Sample clamping method: When using a pendulum hammer machine to measure the bonding strength between PVC and aluminum foil, according to the force measurement principle of the pendulum tensile machine, it can be introduced: the force measured by the testing machine is the sample in the vertical direction. force. If the direction of the force exerted by the test deviates from the vertical direction, then the measured force is its component force in the vertical direction, and therefore less than the force actually received by the sample. In other words, if the line of action of the force exerted by the specimen deviates from the vertical line passing through the center of the fixture, the test result will be low. Therefore, the center line of the jig, the line of action of the force applied to the sample, and the vertical line should be overlapped.
3 test machine tensile speed: test machine tensile speed selection value is different, the test value is different. With the increase of the drawing speed, the value of the heat seal strength increases, so the drawing speed that must be grasped is 200 mm/min.
4. The inspection method for the pharmaceutical aluminum foil blister finished product packaging is to inspect the quality of the sealing of the blister finished product packaging. After the medicine packaging, the sealing performance test is performed. The method is: put the sample into an external pressure that can withstand 0.1M Pa. In the container, tightly seal the lid and vacuum until the vacuum level is 80±13 KPa. After 30 seconds, add the coloring water. The sample is pressed with a pressure plate to prevent it from floating in the water. The surface of the water is not less than 25 mm above the surface of the sample. Then return to normal pressure, open the lid and check for liquid infiltration in the blister. In addition, hygienic tests should be conducted after the medicines are packaged. Test conditions are temperature 40 °C ± 2 °C, relative humidity 70% ~ 75%, after 14 days to remove the sample, according to drug standards to verify compliance with the requirements. (White Ice)
Pharmaceutical blister packaging coating quality analysis and detection method
Abstract : This paper analyzes the factors influencing the coating amount of pharmaceutical blister packaging aluminum foil, including: the number of anilox roller screens, the depth and shape of the cell site, the binder concentration and density, the hardness and pressure of the rubber roller, and coating The use of scrapers in the installation. The test of heat seal strength of aluminum foil and PVC rigid sheet and the inspection method of aluminum plastic blister packaging are described.