The most gunpowder blister package I

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Blister packaging of drugs (I)

at present, the form of blister packaging for pharmaceutical tablets and capsules is becoming more and more common. Blister packaging of drugs, also known as PTD (press through packaging), is a combined process of using industrial pure aluminum foil as the base material, printing text patterns on the surface of aluminum foil and applying protective agent on the other side of aluminum foil with gravure printing technology and roll coating method on the pharmaceutical "PTP" aluminum foil coater. The brief process flow is: aluminum foil unwinding - → gravure printing - → drying - → coating protective layer - → drying - → coating adhesive layer - → drying - → aluminum foil reeling. In the whole production process, it is necessary to strictly grasp the surface quality of gravure printed text patterns, the heat sealing strength of adhesives and the quality control in the coating operation process. Therefore, this paper analyzes the factors affecting the heat sealing strength and coating amount of aluminum foil, and expounds the coating amount of aluminum foil and the inspection method of finished product packaging, in order to ensure a higher qualified rate of products.

I. factors affecting the coating amount of aluminum foil

1 The number of lines, hole depth and shape of the coating roller

most aluminum foil coating equipment adopts the roller coating device, so it is called the roller coating method. The wrinkle roll is composed of holes and walls. The concave points on the roll are usually called holes, and the high parts are called walls or lines. The surface of the corrugated roller is plated with a thickness of 0 02mm hard chromium to increase the surface hardness of the roller, and its hardness value is HRC. When the aluminum foil coating device is used for coating, the working principle of the corrugated roller is: when the adhesive fills the hole of the corrugated roller, the corrugated roller rotates. When the hole leaves the liquid level of the adhesive, the liquid at the smooth part of the roller surface is scraped by the scraper, and only the liquid that cannot be scraped from the hole is retained, and this liquid (adhesive) then contacts the surface of the coated aluminum foil substrate. This contact is achieved by the action of an elastic rubber pressing roller, so that part of the adhesive solution in the hole is transferred to the surface of the aluminum foil substrate. Due to the fluidity of the adhesive, it will slowly and automatically level on the surface of the aluminum foil, so that the original discontinuous liquid becomes a continuous and uniform liquid layer

a part of the liquid in the wrinkle roll cavity is transferred to the aluminum foil, and the wrinkle roll rotates at the same time. After rotating for one week, it will be immersed into the adhesive liquid again, and the liquid adhesive will fill the cavity. In this way, a wrinkle roll with small diameter can continuously and evenly transfer the adhesive solution to the aluminum foil substrate, so that the aluminum foil surface can achieve the purpose of evenly coating the adhesive. Obviously, if there are fewer lines per unit area on the wrinkle roll and the holes are deeper, the coating amount is larger. When the higher the number of lines and the shallower the hole, the less adhesive is filled and the coating amount is relatively small. In addition, the hole shape of the corrugated roller is different, and its coating amount, especially if the optical instrument fogs due to improper protection and use, is also different. For example, for a 200 pyramid shaped corrugated roller, there are 200 holes per inch and about 8 holes per millimetre and a half, and the storage capacity of the adhesive is 0.59b/in2, that is, 24g/m2. However, the hole and adhesive stock of 24 triangle thread shape can reach 13b/in2, that is, 63g/m2. 

2. The concentration and density of adhesive solution

for the wrinkle roller that has been made in the production process, its hole depth and number have been fixed, and the hole shape can no longer be changed. Under such conditions, the coating amount depends on the concentration and density of the adhesive preparation. We know that the coating amount is the mass (grams) of dry film bonded solid materials per square meter of aluminum foil substrate area. Therefore, if the solid content of adhesive solution is high, there will be more dry film bonded solid materials and large coating amount when applied to aluminum foil substrate. It is concluded that the relationship between the coating amount and the concentration and density of the adhesive and the hole depth is that the coating amount is directly proportional to the hole depth and the concentration and density of the adhesive. If the hole depth of the wrinkle roll has been fixed in the actual production operation, the coating amount is determined by the concentration and density of the adhesive liquid. Similarly, if the concentration and density of adhesives are determined, more chemical raw materials will be produced; To optimize the product structure, the adhesive coating amount is determined by the hole depth. 

3. The hardness and pressure of the rubber press roll in the coating device

hole depth and adhesive concentration. After the density is determined, the coating amount of the corrugated roll is also affected by the hardness and pressure of the rubber press roll in the coating device, especially the pressure on the left and right sides of the rubber press roll should be uniform, which requires that when making the rubber roll, the mixing procedure in the rubber processing process should be uniform, and the vulcanization conditions should be strictly controlled to ensure that the hardness of the rubber roll is uniform. If the rubber press roll used is very soft, elastic, and the pressure acting on the roll is very large, the coating amount of adhesive will be reduced, because the rubber roll is squeezed into the groove roll cavity deeply under heavy pressure, extruding a part of the adhesive solution, thus reducing the coating amount of adhesive. In practice, the pressure of the rubber roller on the corrugated roller should be controlled within the range of MPa. 

4. Application of scraper in coating device

① scraper pressure. At present, the ways to adjust the scraper pressure device in aluminum foil printing and coating equipment are "Tension spring pressure regulation, handwheel pressure regulation, cylinder pressure regulation and pressure hammer pressure regulation. During the coating operation, if the pressure of the scraper acting on the wrinkle roll is small, or even not tight, or there is the next step of mechanical impurities on the scraper, the scraper will be pushed up to cause gaps, resulting in uneven coating and increased coating volume. China is a large textile country. The factors affecting the pressure of the scraper are: different hard and soft blades, different angles between the scraper and the wrinkle roll. In actual operation Taking the pressure hammer adjusting scraper as an example, the scraper pressure is generally about 200 ~ 400kPa. (to be continued)

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