Common production technology of plastic bottle for medical use

1. Hollow Extrusion Blow molding

Hollow extrusion blow molding is made by using the extruder to extrude the hollow tube continuously, and then using scissors (manual) or cutting device (automatic) to cut it into small sections and then moved to the blow mold to make the shape.

Its advantages are: simple equipment, small investment, low cost price;

Disadvantages are: uneven bottle mouth, poor sealing performance.

In addition, hollow extrusion blow molding process is applicable to the plastic raw material is PE, LDPE commonly used, its permeability is far lower than HDPE and PP, charging shelf life is short.

2. Two steps Injection-blow molding

The two-step injection-blow method actually refers to the operation of injection and blow molding respectively by two machines, commonly known as the two-step method.

To be specific, the first step is to inject the tube blank by an ordinary injection molding machine. At this time, the bottle head part (bottle mouth and thread) of the tube blank has been formed.

The second step is to manually place the tube billets on a honeycomb heater or an automatic cyclic heating conveyor belt. After heating and temperature-adjusting, the tube billets are then moved to the bottle blower and blown into the mold with compressed air.

The advantages of this method are: simpler equipment and less investment;

Neat bottle mouth, good sealing performance;

The product variety development speed is fast, the mold cost is relatively low.

Its disadvantages are as follows: the injection tube billet and blow molding are carried out step by step, so that the products are easy to be contaminated, and it is difficult to ensure that the products pass the bacterial test;

The identity of the product is poor, not suitable for mass production.

3. One Step injection-blow molding

One-step "injection-blow" means that the injection and blow molding are done on the same machine.

According to different types of machines, usually divided into three stations and two stations "injection - blowing".

The three stations of the "injection-blow" bottle making machine are distributed in an equilateral triangle with an Angle of 120°. Among them, the first station is the injection molding station, the second is the blow molding station, and the third is the debottling station.

These three stations can be operated at the same time, which not only greatly improves the production efficiency, but also can be connected with the conveyor belt and automatically count the packaging, truly realizing the "no hand contact" in the whole production process of plastic bottles for medicinal use, thus ensuring the cleanliness and hygiene of products.

The two stations of the "injection-blow" bottle making machine can be arranged up and down or in front of each other. The first station is the injection molding station and the second is the blow molding station.

Due to the lack of a dedicated debottling and cooling station, it is difficult to achieve automatic counting packaging (generally manual counting in bulk).

Compared with the three-station bottle making machine, its production efficiency is lower and the production cycle is longer.

The advantages of one-step injection-blow process are: high degree of automation, large machine capacity;

High flatness of bottle mouth, excellent sealing.

When choosing HDPE/PP as the raw material, the wall thickness of the bottle is relatively uniform, and the anti-permeability performance is excellent, so that the quality of the drug storage for a long time.

Its disadvantage is: the equipment investment is large, the mold is complex, the system configuration request is high, therefore, does not suit the small variety, the small batch production.

However, for mass production, high quality and low cost products can be obtained with better economic benefits.