Understanding The Difference In various materials of Clear Poly Bags
When purchasing clear poly bags, many buyers often hear packaging manufacturers discuss specialized terms related to plastic packaging materials. Beyond the familiar materials, there are also many materials whose properties are unclear. Are you also worried about this?
In the world of plastic packaging, plastic bags come in a wide variety of materials. From food packaging to practical stationery, from beautiful gift wrapping to tightly sealed medicines, clear plastic bags are found almost everywhere in our lives. Why do some common, clear poly bags on the market feel hard, while others are soft? And why are some only suitable for specific applications?
These may all be caused by differences in materials. Many of MTPAK's flexible packaging clients have expressed confusion about materials and interest in new packaging material trends. The core value of MTPAK is to transform these complex material characteristics into scenario-based solutions and provide complete end-to-end services. This article provides an introduction to the materials used in clear poly bag solutions. Hope to help you understand the differences in clear poly bag materials and avoid pitfalls when choosing the right one.
What Materials Define the Quality of Clear Poly Bags?
The first factor that determines performance is the film itself. The quality of plastic is not related to color, but to its composition.
1.PP
PP， the full name is polypropylene, and the plastic stools, storage boxes, lunch boxes, and aviation cups we see are all made of this type of material. Polypropylene plastic has high temperature resistance and can withstand temperatures above 120℃, making it an ideal choice for making microwave-heated food containers. The packaging bags made of PP have high transparency, smooth surface, and excellent glossiness, but their toughness is not as good as PE. Another characteristic is that PP has excellent moisture resistance and a low water vapor transmission rate, which can effectively protect the contents from moisture. However, the printing adaptability of PP film is poor, and it usually requires corona treatment to achieve good printing results.
2.PE
PE， the full name is Polyethylene. The plastic bags used for food on the market are mainly made of polyethylene, which is recognized as the best material for food contact in the world. It is also one of the most widely used and widely used materials for plastic packaging printing. Non-toxic, odorless, and in compliance with food packaging hygiene standards. Polyethylene film has excellent heat sealing performance, but low transparency. The disadvantage is that it generally has poor heat resistance and is prone to deformation at high temperatures. According to density differences, it can be divided into two categories: high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Shopping bags made of HDPE have a stiff feel and a frosted surface, commonly found in supermarket tote bags and express packaging. LDPE is softer and more transparent, commonly used for making food preservation films and lightweight packaging bags. It has strong extensibility and maintains toughness at low temperatures, making it suitable for frozen food packaging.
3.PET
PET， the full name is Polyethylene terephthalate, which is commonly used as a packaging material for mineral water bottles, beverage bottles, and other products on the market. This material has amazing tensile strength and is mostly used for vacuum packaging of coffee beans, nuts, and other foods that require long-term preservation. PET material has a light transmittance of over 90% and good printing adaptability. Some high-end gift packaging is also often made of this material. However, in humid and hot environments, PET may undergo hydrolysis reactions, which can affect its service life.
4.PVC
PVC， the full name is Polyvinyl chloride, which is a highly plastic material that can remain soft at low temperatures and is not easily brittle or cracked. It is particularly suitable for making storage accessories that require frequent bending, such as raincoats and PVC transparent label bags that are convenient for carrying around. Due to the production of toxic gases such as hydrogen chloride during the incineration of PVC materials, they are almost not used for food packaging and are mainly used in industry as shrink wrap and packaging for some stationery. Nowadays, this material has gradually been replaced by other environmentally friendly materials in food packaging.
5.PA
PA， the full name is Polyamide, commonly known as Nylon. It is a soft material with good oxygen barrier properties, good toughness and wear resistance, and is not easily damaged during use. It is particularly suitable for packaging meat products and other foods that require oxygen isolation to maintain freshness. PA and PE are often combined in composite materials to ensure packaging strength and heat sealing performance, killing two birds with one stone. However, PA material is prone to moisture regain in humid environments, causing product deterioration. Therefore, moisture prevention should be taken into account during storage.
6.Other composite materials
Nowadays, plastic packaging mostly uses multi-layer composite materials, which can take into account the advantages of various materials. A typical example is the aluminum-plastic composite film combining PE and AL, which is widely used in products such as milk powder and pharmaceuticals.
7.Specially designed special materials
With the upgrading of technology and the increasing demand for high-quality, plastic packaging materials specifically designed for use in special scenarios, have emerged.
- Anti-static PE bag: used for packaging precision electronic components and other equipment.
- Co-extruded EVOH film: It has excellent barrier properties and is used for packaging dairy products, alcoholic beverages, coffee, and other products.
- PVDC: It has excellent high-barrier properties and is commonly used in the packaging of ham sausages and cold fresh meat.
From an environmental perspective, which material is most suitable?
Taking the materials introduced above as an example, PP and PE are both polyolefin plastics with the strongest recyclability. They are currently the most environmentally balanced general-purpose plastic materials, with core advantages focused on low production energy consumption and no toxic substance release. And both are easily recyclable plastics.
PET material is the mainstream material for beverage bottles and food packaging, followed by environmental friendliness, and the recycling system is currently quite mature, but the production energy consumption is higher than PP and PE.
PA, which is commonly used for industrial accessories and high-end packaging, has significantly weaker environmental friendliness than the first three. The core issues are high production energy consumption and an imperfect recycling system.
Composite materials, due to the use of multiple layers of different materials stacked together, have lower environmental performance than single materials, and the difficulty lies in their difficulty in separation. In unavoidable situations, it is important to choose products that are clearly labeled as recyclable.
PVC is currently recognized as the plastic material with the highest environmental risk, and its use in food and daily necessities has been restricted in many countries around the world. The EU REACH regulation has strictly restricted the use of PVC in food packaging.
Therefore, based on the materials mentioned above, the recommended ranking for environmental protection is as follows:
PP=PE>PET>PA>Composite material>PVC
From a budget perspective, which material is most suitable?
Taking the materials introduced above as an example, to determine which material has the most suitable budget, it mainly depends on the comprehensive cost, including the unit price of raw materials, processing difficulty, and other implicit costs.
Among them, PVC has the lowest material unit price, but it is only suitable for industrial scenarios.
PE (especially LDPE) has relatively inexpensive raw materials and simple processing, making it the preferred choice in general scenarios.
The unit cost of PP is slightly higher than that of PE, but it has good processability and a wider range of adaptability scenarios. Its overall cost-effectiveness is similar to that of PE.
PET can enhance texture without the need for composite materials and can be recycled for secondary processing, making it the preferred choice for those with a moderate budget but a desire for texture.
The cost of PA material is 2-3 times that of PE and PP, and its high strength and puncture resistance are irreplaceable. But it is difficult to process and is suitable for scenarios with performance requirements, such as PA vacuum bags, pet food bags, etc.
Finally, it must be mentioned that composite materials have the highest cost among the materials mentioned above, and are suitable for scenarios where the budget is sufficient and a single material cannot meet the requirements.
Therefore, based on the materials mentioned above, the budget ranking is as follows:
Composite material>PA>PET>PP>PE>PVC
However, there is no absolutely cheapest material, only relatively compatible materials. Achieving a balance between the two is the aspect that procurement managers need to consider. After all, the core of a suitable budget is not wasting.
Conclusion
There is no absolute distinction between good and bad materials for clear poly bags. Choosing the most cost-effective and well-protected option based on specific product characteristics and needs is the most practical approach.
If you need to customize clear poly bags for your business, please contact us for the most suitable solution and the latest trends in plastic material development.
At MTPAK, we have a diverse team of experts who understand the real needs of customers in different fields and keep up with industry trends, providing one-on-one professional services. Our services include customizable, flexible packaging, high-quality printing and coating, and research and development of sustainable packaging solutions. Currently, we have served global enterprises covering markets such as pet food, beverages, dry food, roasted coffee, and personal care.
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