Processing and application of high density polyeth

Processing and application of medical high-density polyethylene bottles

from the 1960s to 1970s, the packaging of drugs in solid dosage forms in China was mainly yellow round glass bottles. Because the traditional raw material of glass was mainly calcium sodium glass, which was blown manually or mechanically in a glass furnace, the process was relatively traditional and backward. Due to the rising price of glass raw materials, high energy consumption, and gradually rising production costs, glass would also produce dust Waste water, noise and other environmental pollution. Therefore, the profits of glass production enterprises are generally low, which restricts the technological transformation and further development of enterprises. Medicinal glass bottles are also easy to break during transportation and use, with a crushing rate of 10-30%, which further increases the production cost. In addition, before using glass bottles to contain drugs in pharmaceutical factories, the bottle body needs to be cleaned and disinfected. After charging, corks need to be inserted into the mouth of the bottle to seal with wax. Such a production process is far from meeting the requirements of drug packaging. In order to change the backward situation of drug packaging in China, in the early 1980s, the former Shanghai No.3 glass factory, No.5 glass factory, Tianjin Lisheng pharmaceutical factory and Shandong Xinhua Pharmaceutical Factory first introduced advanced injection blow molding equipment from American "Witton" company and German "bartonfield Fisher" company to produce plastic bottles for solid dosage form packaging of drugs. Later, other packaging industries in China introduced more than 40 high-quality plastic bottle production lines. The production process of this one-time injection blow molding equipment is: first, the screw thread part of the bottle mouth is molded in a closed environment, so as to ensure the dimensional accuracy of the bottle mouth and screw thread part, and then blow molding the bottle body. This molding method meets the special requirements of the packaging of solid dosage forms of drugs, and can prevent the volatilization of the drug gas contained in the bottle and the penetration of external polluted air into the bottle

at present, the domestic pharmaceutical tablet packaging has gradually realized the transformation of "plastic" instead of "glass". The processing and application of high-quality HDPE bottles cannot be separated from reasonable bottle structure design, high-quality raw material formula design, perfect production equipment and mature molding process methods. Therefore, high-density polyethylene bottles are in the ascendant in drug packaging. At the same time, we also summarized a series of mature experience from bottle shape to raw material formula, from equipment molding method to process parameters. From the introduction of equipment and technology since the reform and opening up to now, China has been able to produce injection molding equipment for nearly ten years. The output of bottles has increased from tens of thousands at first to 1.7 billion in 1994 to billions now, basically meeting the needs of solid drug packaging in China

bottle shape characteristics

the external shape of medical high-density polyethylene bottle includes round, square, oval, etc. Circular bottle bodies are the most widely used, especially those with a capacity of 15 ml to 200 ml. they are characterized by uniform wall thickness, high ability to absorb external impact energy, low production cost, but low utilization of effective area during storage or transportation. The square bottle has high utilization rate of effective area and good stability, but it is prone to bottle bulging and deformation. Oval bottle body is the least used in drug packaging, while cosmetics packaging is more used. Due to the large amount of HDPE bottles, the appearance is beautiful. It is suitable for the packaging of solid dosage forms of drugs, and its bottle shape design has characteristics. The design of round bottle mouth, bottle neck shoulder and bottle bottom is reasonable, which has some characteristics:

first, in order to facilitate the mechanical loading of tablet and capsule solid dosage forms, the design of bottle mouth diameter usually considers the single volume of drugs plus appropriate residual space. The cross-section of the thread shape at the neck of the plastic bottle is mostly semicircular, which is seen from the outside as two fine threads, and there are also trapezoidal threads, which are called single head threads. The shape design of the neck of the bottle mouth, regardless of the opening and closing thread, mainly depends on the good compatibility of the bottle cap, because the moisture resistance of the drug packaging largely depends on the tightness of the bottle mouth and the bottle cap after the torsion is applied. Here is the main part to reflect whether the sealing performance of the bottle mouth is excellent. The original design is that there is a sealed gasket in the bottle cap and an anti-theft cap is used outside. This anti-theft bottle cap can provide visible traces of seal damage. Its structure is mainly that there is a circle of small holes around the bottle cap along the bottom of the side skirt to form a disconnection line. When twisting the bottle cap, because the corrugated flanging pawl is tightly locked under the convex ring at the lower end of the bottle mouth, reverse rotating the bottle cap can be done. Open the oil return valve first and break the lock ring along the folding line. Now the plastic bottle mouth is sealed by electromagnetic induction with aluminum foil gasket, which has the properties of moisture-proof, sealing and anti-theft at the same time. It is unnecessary to use the form of anti-theft cap

secondly, from the design of HDPE bottle neck and bottle shoulder, the longitudinal anatomy of the bottle body section shows that the bottle neck and bottle shoulder are composed of two tangent arc radii, and are divided into two sections from the tangent point. During the design, the distance between the bottleneck and the center line, the radius of the shoulder and the radius of the neck arc should be calculated, and the total height of the bottleneck and the bottle shoulder should be obtained accordingly. The main factor affecting the strength of the bottle shoulder is the inclination angle of the bottle shoulder. When the bottle shoulder is too flat, the bottle body is prone to collapse. Therefore, when the length of the bottle shoulder is 10 mm, the inclination angle of the shoulder should be more than 15 degrees, and the thickness of this part should not be less than 1 mm, so as to ensure that the bottle body will not break during the process of containing and storing drugs and using. Third, the bottle body of the high-density polyethylene bottle is a cylindrical round, that is, 300000 mu of land for agricultural reclamation and 1.5 million mu of forest land have been added. The requirement for the bottle body is that the wall thickness is uniform. If the bottle wall is too thick, the weight of the bottle body will increase, the consumption of raw materials will increase, at the same time, the internal stress of the bottle will increase, and the shrinkage will also increase. The bottle wall is too thin, difficult to blow molding and low strength. The general requirement is that the wall thickness of other parts should be uniform except that the stiffener and thread at the bottle mouth are thicker than the bottle body. In order to improve the barrier property and strength of plastic bottles, the thickness of the bottle body is generally 1 5 mm. The bottom of plastic bottles are mostly designed with concave bottom or flat bottom double fillet structure. Concave bottom means that the bottom of the bottle is concave to the inside of the bottle to form arch holes, which can enhance the internal pressure resistance of the bottle body and ensure the stability of the bottle body. The concave bottom can also avoid plastic collapse and make the thickness of the bottle bottom uniform during blow molding. The flat bottom double rounded bottom structure is mostly suitable for large volume bottle bottom, which can better withstand internal pressure

bottle body raw material formula

in the bottle body formula design, first determine whether the variety of plastic raw materials can meet the requirements of equipment molding. Such as whether the melt index and physicochemical index of plastic raw materials can meet the performance of finished products. At present, the main raw materials are high-density polyethylene (HDPE) and polypropylene (PP). These crystalline plastics have good impact resistance, environmental stress resistance, chemical resistance, good gas barrier, moisture resistance and non-toxic. The second is to choose plastic compounding agents, such as sunscreen, colorant, plasticizer, etc. Because the light range that has the greatest impact on the quality of drugs is the light with nanometer intensity. The United States Pharmacopoeia and the Japanese Pharmacopoeia stipulate that the light transmittance of the plastic bottle to the above range shall not exceed 10%, so as to ensure that the drugs will not deteriorate due to light exposure. The selected compounding agent has good chemical resistance, migration resistance and light resistance, can maintain good mechanical strength and dimensional accuracy of the bottle body, and is non-toxic. The purpose of adding plasticizer is to improve the processing performance and reduce the intermolecular force of plastic in the process of injection blow molding, so it is easy to label the surface of the bottle, otherwise it is not possible to label with ordinary adhesive. When the plastic varieties and compounding agents are determined, the basic formula should be formulated according to a certain proportion, and the variable experimental method of the formula should be determined to make the dosage of various compounding agents reasonable. The optimized formula determines the test method that can reflect the special mechanical properties, and carries out physical property tests, such as impact resistance test, drop test, weather aging resistance test, stress cracking resistance test, etc. Finally, we should also carry out variable tests on the basic formula in the laboratory, so as to select the best formula, and continue to retest. In the test results, we should select the trial products of the best formula, so as to ensure that the processing performance and various physical properties of plastics and compounding agents are reliable and reasonable, and meet the best process conditions when the equipment is running, so as to determine the practical formula for mass production

molding methods of equipment there are many molding methods of plastic bottles. The external shape and accuracy of the produced bottles are also different with the selected equipment. The molding methods include extrusion blow molding method, injection blow molding method, extrusion blow molding, injection blow molding, etc. Usually, small medical plastic bottles are molded by injection blow molding. The nozzle of the equipment can inject plastic into the bottle mouth, which can ensure the accuracy of the bottle mouth and the thread. Then, the mechanical mandrel is used to blow mold the bottle body, which ensures the accuracy and size of the plastic bottle body. As the injection blow molding machine requires two sets of molds (one blank mold and one blow molding mold), the equipment investment cost is higher than that of the extrusion blow molding equipment

plastic bottle molding process parameters

due to the different accuracy and types of equipment, the process parameters are different, but the design principles should be consistent. When the shape, size and formula of high density polyethylene (HDPE) or polypropylene (PP) bottles are determined, the molding process parameters of the bottle body can be determined according to the characteristics of the blow molding equipment, Its parameter setting contents and principles include:

◆ injection and blowing machine barrel temperature parameters

◆ equipment injection channel and nozzle temperature parameters

◆ blow mold temperature and bottle cooling time parameters

◆ injection pressure parameters

◆ injection speed parameters

◆ blow molding pressure and blow molding speed parameters

use of bar code

drugstores, supermarkets and chain stores must achieve "single product" management, To realize barcode management. For each kind of commodity and drug, according to its attributes and characteristics and certain rules, a "background code" must be compiled, which is the basic work necessary for computer management. The "background code" usually includes commodity categories, medium categories, sub categories, suppliers, cabinet groups, materials, sizes, colors, brands and other contents, which rely on computers to carry out statistics and analysis according to the "background code".

it must be pointed out that "foreground code" and "background code" cannot be confused. The "background code" is usually more than 20 characters long, so it cannot be used as the foreground operation code. On the contrary, the foreground operation code cannot be too long, usually no more than 13 digits, which is not enough to completely represent the attributes and characteristics of the commodity

in foreign shopping malls that use bar code management, there are two methods: one is to use the "in store code" made by the user regardless of whether there is bar code on the goods, and the other is to make full use of the original bar code on the goods, and mark the goods without bar code with the in store code made by the user

the former is basically middle and high-end shopping malls or specialty stores, and the latter is basically all supermarkets and chain stores. Because the value of goods is low and the sales volume of goods is large, using all store codes will increase the cost of goods

the advantage of using all "in store codes" is that you can compile "in store codes" according to your own requirements for managing goods, so as to meet your own management requirements. Another advantage is that automatic flow operation can be adopted