Injection blow and injection stretch blow bottles are usually used as packaging for food, medicine, cosmetics and daily chemical products. They not only have distinct bright spots, but also have their limitations. Generally, when evaluating what kind of bottle packaging a product uses, the specific use requirements, characteristics, and cost of the product must first be analyzed in detail. Then evaluate and select according to whether the characteristics of various bottle production processes meet the requirements.

Under normal circumstances, there is not only a single solution, and a variety of designs can be selected according to the requirements. The following briefly introduces some application cases and design ideas of injection blowing and injection stretch blowing bottles in various fields.


Common cases of injection blowing and injection stretch blowing

Case 1
One-step injection stretch blow PET bottle
Application in the packaging of medicinal oral liquids
Injection stretch blow PET bottles are widely used in pharmaceutical packaging, and are commonly used in the packaging of pharmaceuticals including oral solids, oral liquids and eye drops. Different uses have different requirements for bottles.

The following uses the injection stretch blow PET bottle for oral liquid medicine packaging as an example to introduce the application and general design ideas of the one-step injection stretch blow PET bottle in the medicine packaging. Example: Design a medicinal cough syrup packaging bottle with an annual sales forecast of 5 million bottles and a capacity of 100ml for a pharmaceutical company.

Basic requirements: 1. The bottle material and performance meet the national requirements for oral liquid packaging bottles. 2. Convenient for transportation, packaging and consumer use. 3. The bottle is beautiful in appearance and has corporate LOGO graphics.

You can refer to the following ideas:
One is to evaluate the material of the bottle, and the materials that can be used are glass and plastic. However, glass is not convenient for packaging, transportation and safe use due to its high specific gravity and fragility. There is no special reason to use plastic materials as much as possible.

The second is the choice of specific materials and production processes. In general, the two are related. Considering that it is used for packaging oral liquid medicines, PET materials can be considered. PET materials have excellent gas barrier properties and chemical stability, which can meet the national regulatory requirements for oral liquid medicine packaging. At the same time, PET material has good surface gloss and impact resistance, which is not only beautiful but also meets packaging and transportation requirements. In addition, PET’s versatility and cost are also standard advantages.

In terms of molding process, one-step injection stretch-blowing process can be considered, and the mouth size and thread accuracy can be well guaranteed. It can be directly matched with the lid for sealing, without using gaskets or inner plugs. Convenient and cost-saving. At the same time, the one-step injection stretch-blow process completes the injection of the parison and stretch-blow molding in the same equipment, ensuring the sanitation of the product. It is more conducive to medicine packaging.

The third is the appearance design of the product. The bottle mouth can adopt a circular thread structure, which is simple and conducive to mold design, process molding and packaging sealing effect. It can be used with PP/HDPE material safety cover. The appearance of the bottle is more flexible, and it can adopt a traditional cylindrical shape or other shapes.

The fourth is secondary processing. Scale lines can be engraved on both sides of the mold clamping line to facilitate each quantitative use. At the same time, brand information such as simple text or patterns can be engraved on the bottle body and bottom. For secondary processing, due to the higher requirements of medicine for hygiene and safety. Generally, simple surface labeling methods are used to give information such as product brands and various descriptions. Less used for other secondary processing.

The last is the design of the number of mold cavities. For one-step injection stretch blowing, the price is generally higher due to more mold parts. Molds with more cavities have higher production capacity and lower unit product manufacturing costs, but the initial mold costs are relatively large. Molds with fewer cavities have lower production capacity and higher unit product manufacturing costs, but the initial mold cost investment is small.

In this case, the annual quantity of 5 million bottles uses a 6-cavity mold, and the initial mold investment and output are more suitable. The price of the mold varies greatly depending on the quality of the mold and the manufacturer. For bottles with a capacity of about 100ml, the one-step injection stretch-blowing 6-cavity mold output can reach 25,000-35,000 bottles/24H, which is relatively suitable.

Therefore, for this case, the alternative solution is to use the PET bottle produced by the one-step injection stretch-blow process with a scale or LOGO on the bottle body.

Case 2
One-step injection stretch blow PET bottle combined with multiple secondary processing effects applied to high-end cosmetic bottles
One-step injection stretch blow PET bottle combined with multiple secondary processing techniques is also a common packaging method for cosmetics. Different from medicine or food packaging, medicine or food packaging bottles pay more attention to the safety and hygiene of bottle materials. The cosmetic packaging bottle focuses more on the beauty and grade of the bottle. Therefore, in addition to ensuring the quality and function of the bottle itself, the secondary processing technology of cosmetic bottles is more widely and diversified.

The following is an example of a plastic bottle used for toner packaging from a cosmetics company:

1. Basic information of the bottle: the capacity is 120ml, and the weight is 20g. Used in toner packaging.

2. Bottle material and process: The bottle is formed by PET material and one-step injection stretch-blowing process, which has the advantages of high transparency and good gloss, combined with the high stability and high precision characteristics of the one-step injection stretch-blowing process. Make the bottle itself more beautiful.

3. Bottle structure: The mouth of the bottle adopts a small-diameter thread structure, with precise dimensions in injection stretch-blowing technology, and is matched with LDPE inner plug and combined outer cover. Form a reliable sealing effect.

4. According to bottle size, wall thickness requirements and process requirements. Designed with a weight of 20g, the bottle body has sufficient rigidity and good hand feeling while ensuring the even distribution of the wall thickness of the bottle, which can meet the rigidity requirements of the secondary processing such as bronzing, but does not affect the extrusion of the contents. Out.

5. The bottle adopts three secondary processing techniques, the text description and bar code part adopts the screen printing process, the key graphics adopts the hot stamping process, and the final bottle is sprayed with gradual colors. With the electroplated combination lid, the bottle is very beautiful and high-end overall.

Generally, PET bottles are highly adaptable to secondary processing technology, and the safety and sanitation requirements for bottles are not as strict as medicines and foods, making secondary processing options more flexible and diversified. It just meets the needs of cosmetic packaging. Therefore, PET injection stretch blow molding is more and more widely used in cosmetic packaging.

1. The material of plastic bottle is usually PP, PE, K material, AS, ABS, acrylic, PET, etc.

2. Generally used in cosmetics containers with thicker walls, cream bottles, bottle caps, stoppers, gaskets, pump heads, and dust covers are injection molding; PET blow molding is two-step molding, tube embryo is injection molding, and finished product packaging For blowing. Others, such as emulsion bottles and washing bottles with thin container walls, are blown bottles.

3. The PET material is an environmentally friendly material with high barrier properties, light weight, non-breaking characteristics, chemical resistance, and strong transparency. It can be made into pearlescent, colored, magnetic white, and transparent, and it is widely used in gel water. The bottle mouth is generally standard 16#, 18#, 22#, 24# caliber, which can be used with pump head.

4. Acrylic is made of injection molding bottle, which has poor chemical resistance. Generally, paste cannot be directly filled. It needs to be equipped with an inner tank to block it. The filling is not easy to be too full to prevent the paste from entering between the inner tank and the acrylic bottle. In order to avoid cracks, the packaging requirements are high during transportation. It looks particularly obvious after scratches, has high permeability, and the sensory upper wall is very thick, but the price is quite expensive.

5. AS, ABS: AS has better transparency and toughness than ABS.

6. Mold development costs: blowing molds range from 1500 yuan to 8000 yuan, injection molds range from 8000 yuan to 50,000 yuan. Stainless steel molds are more expensive than alloy materials, but they are durable. Several molds can be produced at a time. The demand of production volume, if the production volume is large, you can choose a mold with four or six molds, and the customer can decide by himself.

7. The order quantity is generally 5,000 to 10,000, and the color can be customized. Usually, the primary color is frosted and magnetic white, or the pearl powder effect is added. Although the bottle and cap are matched with the same color master, sometimes due to the bottle and cap The materials used are different, and the colors displayed are somewhat different.

8. The screen printing has ordinary ink and UV ink. UV ink has good effect, gloss and three-dimensional effect. It should be printed to confirm the color during production. The effect of screen printing on different materials will be different.

9. The processing technology of bronzing and silver bronzing is different from that of printing gold powder and silver powder. Hard materials and smooth surfaces are more suitable for bronzing and silver bronzing. Soft surfaces have poor bronzing effects and are easy to fall off. The gloss of bronzing silver Degree is better than printing gold and silver.

10. The silk screen film should produce negative film, the graphic effect is black, the background color is transparent, the hot stamping and silver hot process should produce positive film, the graphic effect is transparent, and the background color is black. The proportion of text and pattern should not be too small or too thin, otherwise the effect will not be printed.

11. Bottle caps are generally equipped with inner gaskets, pull caps, and inner plugs. Very few are equipped with small spoons or droppers. This is mainly due to its tightness and ease of use.

12. The production cycle is relatively moderate, about 15 days. The silk-screened cylindrical bottle is calculated as a single color, and the flat bottle or special-shaped bottle is calculated as two-color or multi-color. Usually, the first silk-screening fee or fixture fee is charged. The unit price is generally 0.08 yuan/color order to 0.1 yuan/color order, the screen version is 100-200 yuan/model, and the fixture is about 50 yuan/unit.

Extrusion process

Due to its chemical stability, HDPE materials are widely used in primary packaging (direct contact products) of many products such as bleach, motor oil, detergent, milk, distilled water, and condiments. The chemical, thermal and mechanical properties of HDPE will not be described in detail here, and interested readers can study it in depth.

The extrusion blowing process is widely used in the production process of HDPE plastic products. The common commodity packaging produced by the extrusion process are: shampoo bottle, laundry liquid bottle, solid particle medicine bottle, barreled seasoning, oil drum, Auto parts, etc.

Simulation animation of extrusion process:


Brief introduction of one-step injection stretch blowing process

One-step injection stretch-blow plastic hollow molding is the world’s most advanced stretch bottle manufacturing technology. It uses high-pressure and high-speed injection of preforms, axial stretching of the preforms, bidirectional blow molding, and cooling and shaping. The injection, stretching, and blow molding processes are completed in sequence on one equipment, which is the “one-step” bottle manufacturing process.

After the plastic bottle is stretched, the comprehensive mechanical properties such as transparency, surface rigidity, impact resistance, gas barrier and permeability have been greatly improved, the production efficiency is high, and the internal quality and dimensional accuracy of the product can be easily guaranteed.

Brief introduction of one-step injection stretch blowing process equipment
The main machine of the one-step injection stretch-blow process equipment is the injection stretch-blow plastic hollow molding machine and its injection stretch-blow mold, which are mainly composed of injection device, lifting and indexing device, stretch blow molding device, demoulding device, hydraulic system, and air circuit system , Electronic control system, microcomputer automatic control system, frame, safety cover, injection preform mold, stretch blow molding mold and other parts, integrated injection stretch blowing special control computer, frequency conversion controller, electro-hydraulic proportional control system, Some advanced process equipment such as hot runner molds.

The auxiliary equipment of one-step injection stretch blowing equipment mainly includes plastic dehumidification dryer, air compressor, air dehumidifier, mold cooler, etc. It is an integrated high-end technical equipment of “mechanical, electrical, hydraulic, pneumatic, and microcomputer”. The project innovatively integrates some advanced technologies such as PID temperature control technology, frequency conversion technology, microcomputer automatic control technology, hot runner mold technology, and the two-step method of extrusion blow molding machine, injection blow molding machine, and injection stretch blow molding commonly used in China. Compared with equipment, it has obvious technical advantages in many aspects such as automation degree, yield, energy saving, and waste reduction.

It is suitable for the production of high-end plastic bottles with bottleneck, high precision, good transparency, non-toxicity, and good preservation effect on the contents. It is widely used in processing PET, PEN, PP, PC in the industries of medicine, health care products, food, cosmetics and chemicals. And other high-end packaging bottles.

About injection

In the packaging industry, injection molding technology is becoming more and more popular. The reason is that people use multi-layer molds. This is an advancement in hot runner technology. By adopting the thin-wall injection molding process, the cost of raw materials can be saved. Other special processes such as stamper marking method and multi-component technology have also played a positive role in reducing process steps, increasing yield and improving efficiency.

Plastic packaging materials, especially in the food industry, have made a great contribution to improving our living standards today due to their light weight and good durability. In addition, it would be unimaginable to distribute products produced by large-scale industrialization to all parts of the world without packaging materials. So on the whole, in the past few years, the entire plastic packaging market, mainly deep-drawn packaging plastic films, has grown rapidly. Among them, injection-molded packaging materials, such as packaging boxes or cups, are on the rise and are gradually replacing thermoformed packaging materials.

1. 3 main stages of injection molding

From the definition of injection molding, injection molding is mainly composed of the following three stages.

· Preparation before molding
The work at this stage includes pre-treatment of raw materials, cleaning of barrels, preheating of inserts of plastic parts with inserts, and selection of release agents for plastic products that are difficult to demold. It should be noted that, due to the different types of injection materials, shapes, plastic parts structure, presence or absence of inserts, usage requirements, etc., the preparation work before molding of various plastic parts is not exactly the same.

· Injection process
The entire injection stage includes several steps such as feeding, plasticizing, injection into the mold, constant pressure cooling and demolding.

· Post processing
Carry out inspection and post-processing on the parts to make the quality of the parts stable and reliable, and the appearance meets the requirements. In a nutshell, the post-treatment of the product refers to the process engineering to further stabilize or improve the performance of the product obtained by injection molding, which usually includes stress relief annealing, quenching and tempering treatment, etc.

2. Characteristics of injection molding process

The injection molding process can prepare engineering parts and daily-use plastic parts of different shapes, sizes, quality, and meet various requirements. The characteristics of the injection molding process can be briefly summarized as follows.

(1) The molding cycle is short, such as a few seconds to a few minutes.

(2) It can form all kinds of parts with complex shapes, high dimensional accuracy, good surface quality, and metal or non-metal inserts at one time.

(3) The molding has a high degree of automation. All operations such as clamping, feeding, plasticizing, injection, mold opening and product ejection in the molding process can be automatically completed by the injection molding machine.

(4) It can be adapted to the molding of various major plastics. Almost all thermoplastics, thermosetting plastics and elastomers can be molded by this injection method.

(5) Mold wear is small, easy to load and unload, and high production efficiency.

(6) The rapid development of injection molding technology makes it easier and easier to effectively control the flow characteristics of plastics, the mechanical properties of products, and the appearance quality.

About IML injection

1. For plastic box packaging, at least a 3-sided packaging design

The IML injection molding process can complete multi-sided (3, 4, 5) packaging at one time, which is one of the powerful advantages of this process.

But in the injection IML process, because of the process, it should be at least three sides (bottom plus the front and back of the barrel), or four sides (four sides of a square box), or five sides (bottom plus four sides of the box), or 360° Go around.

2. The label needs mold positioning, and the size of the label is best to fill the entire plane.

In the injection molding process, the label is electrostatically attracted to the inner wall of the mold cavity and positioned by the mold itself. Therefore, for the cap injection IML, the label generally fills the plane of a certain cavity. For boxes, the general requirement is “indomitable”, that is, the bottom of the label is flush with the bottom of the box, and the top of the label is on the plane