Industry information

What are the manufacturing processes of PET containers? - Maypak

June 21, 2023


Product Definition

PET Bottle is based on PET plastic material,

Plastic containers obtained by one-step or two-step processing.

PET plastic has the characteristics of light weight, high transparency, impact resistance and not easy to break.


Manufacturing Process

1. Understand The Preform

A preform is an injection molded item. As the intermediate semi-finished product of subsequent biaxial stretch blow molding, the bottle neck of the preform has been finalized in the stage of injection molding, and its size will not change during heating and stretching/blowing. The design of the size, weight, and wall thickness of the preform is Factors that we need to pay great attention to when blowing bottles.

Preform Structure

Preform Molding

2. PET Bottle Molding

One Step

The process of completing the injection, drawing and blowing processes in one machine is called one-step method. The one-step method is to do stretching and blowing after the preform is cooled after injection molding. Its main advantages are power saving, high productivity, no manual work, and less pollution.

Two-Step Method

The two-step method separates the injection and stretch blowing, and performs time-sharing on two machines, which is also called the injection stretch blowing process. The first step is to inject the preform with an injection molding machine. In the second step, after the preform at room temperature is reheated, it is blown into a bottle. The advantage of the two-step method is that the preform is purchased for blow molding. Can reduce investment (manpower and equipment). The volume of the preform is much smaller than the bottle, which is convenient for transportation and storage. The preforms produced in the off-season can be blown into bottles in the peak season.

3. PET Bottle Molding Process


Material and Structure

1. PET Material

PET, polyethylene terephthalate, referred to as polyester. The English name Polyethylene Terephthalate is produced by the polymerization reaction (polycondensation) of two chemical raw materials, PTA (terephthalic acid) and ethylene glycol (ethylene glycol).

2. Bottle Mouth Common Sense

There are Ф18, Ф20, Ф22, Ф24, Ф28, Ф33 and other diameters (corresponding to the T size of the bottle mouth) through the bottle mouth. The thread specifications can usually be divided into: 400, 410, 415 (corresponding to the number of thread turns). Say, 400 is 1 turn thread, 410 is 1.5 turn thread, 415 is high 2 turn thread.

3. Bottle Body

PP and PE bottles mostly use solid colors, while PETG, PET, and PVC materials mostly use transparent colors, or colored transparency, with a sense of clarity, and less solid colors. The PET material bottle body can also be used for color spraying. The bottom of the blow molded bottle has a bump. Brighter in light. Blown injection bottles have a bonded line at the bottom of the bottle.

4. Matching

Blowing bottle matching mainly includes inner plug (PP and PE materials are commonly used), outer cover (PP, ABS and acrylic are commonly used, there are also electroplating, and anodized aluminum, oil spray toner is often used), pump head cover (essence and emulsion are often used) , Qianqiu cover, flip cover (lift cover and Qianqiu cover are mostly used by large circulation daily chemical lines), etc.


Industry Application

PET bottles are widely used in the cosmetics industry, Mainly in the laundry industry, Shampoo, shower gel bottles, toner, cleansing oil bottles, etc. All are bottle blowing processing and manufacturing.


Purchasing Notes

1. Available materials for bottle blowing, PET is just one of them, there are also PE blow bottles (softer with more solid colors, one-time forming), PP blow bottles (harder with more solid colors, one-time forming), PETG blow bottles (transparent Brightness is better than PET, but it is not commonly used in China, high cost, high cost, one-time forming, non-recyclable material), PVC blowing (harder, not environmentally friendly, transparency is worse than PET, but better than PP and PE brightness)

2. The one-step method is expensive, but the two-step method is relatively cheap

3. PET bottle molds are cheaper.

4. Common quality problems and solutions, see video.

*Maypak packaging is PET Containers Manufacturer and has been focusing on PET containers for more than 17 years and was established in 2006,the company enjoys a good reputation at home and abroad. If you have any questions about lipstick tubes, please contact us.

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