Study Of New Structure Of Plastic Ampoules And Its Molding Method

Ampoule is a kind of small sealed bottle used for storing injecta，vaccines and serum etc. Ampoules are extensively used in transfusion system.Its capacity is about1~25ml,it is also used for packaging of oral liquid.Ampoules were produced by glass at first, and that would produce largenumber of glass particles when opening and that would enter body along withthe injection liquids and do harms to pationts. Moreover, glass ampoules areinconvenient to open, and in the process of using glass ampoules, the sharpglass may do harm to medical staffs. Plastic is becoming the substitute of glassmaterial because of these advantages. Plastic ampoules are more easilymanufactured, sterilized and filled，so one-step process is feasible. Plasticampoules would not produce debris and particles in the opening process, sothat the security is ensured. At present, many kinds of plastic ampoules utilizea fine and deep groove around the neck of the bottle to reduce its strength, andthen the bottle can be opened from the neck. But the groove is too thin to besterilized, and there would be hidden danger when using the ampoules.In this article, an ampoule with new structure is developed to avoid theproblem of sterilizing in the same time it can be opened easily.A new structure was designed to reduce the strength of the neck of thebottle by compositing new material on the parison which would be blowed to shape the ampoule,when tear the neck the bottle would break from the side. Anew method of extrusion blow molding Double-plate Extrusion BlowMolding was developed to solve the problem of compositing other materialson circumference of plastic hollow products’ special positions. The feasibilityof this method was tested by simulation. The quality of molded products underdifferent molding pressures was analyzed. Finally, problems and theirsolutions of this method were raised.The influence of the gap used to tear the plastic sheet is analysed by tests,and feasibility of reducing the strength of the bottle’s neck by compositingnew material is also tested. Tearingenergy is used to describe the tearingproperties of the plastic slice.The innovation are as follows:1、Using the new method to design the structure which is applied foropening plastic ampoules, ensure that the ampoules can be opened andsterilized easily.2、A new method of extrusion blow molding was developed to solve theproblem of compositing other materials on circumference of plastic hollowproducts’ special parts, and it would reduce the cost of the product，and can beused in one-step process.3、Energy analysis in fracture mechanics is used to describe fracturetoughness of plastic slice, tearingenergy is recommended to explain the tearingproperties of the plastic slice, the influence of different kinds of gaps isanalysised.