Introduction

Plastic bag is the most common product we see every day and everywhere. From daily lives to industry, plastic bag plays an important role in making people’s lives easier. Polyethylene bag, also known as PE bag which has been one of the most widely used plastic bags in almost every aspects of our lives especially in packaging.

This article is a guide to PE bag especially Heavy-Duty bags. Heavy duty bags are designed for packaging heavy items in many industries such as fertilizer, pet food, animal feed, activated carbon and so forth. in addition, we also address what is PE bag, types of heavy-duty PE bags, its advantages and disadvantages, the applications of such PE bags and so on. I hope this article will answer the questions you hold for PE bags.

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What is Polyethylene Bag?

Polyethylene or polythene (abbreviated PE) is the most common plastic in use today. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes, containers including bottles, etc.). As of 2017, over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. It is a transparent plastic bag that can be used for packaging of clothing, bags, and electronic products.

Polyethylene is of low strength, hardness and rigidity, but has a high ductility and impact strength as well as low friction. It shows strong creep under persistent force, which can be reduced by addition of short fibres. It feels waxy when touched.

Heavy Duty bags are designed for long distance shipping, as a part of industrial packaging sector, used to transport bulky materials or great amounts of materials from one place to another. Heavy duty plastic bags are constructed using strong polyethylene films which are designed to serve as holding for fertilizers, sand, garden compost, mulch, wood pellets, potting soil, seeds, sand, decorative rocks, and other heavy industrial products. These are strong films distinguished from those of normal PE bags such as shopping bags. According to the material and the weight they are about to hold, film thickness differs in accordance with the weight.

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Types of Heavy Duty Polythene Bag

Generally speaking, there are four major types of bag made from PE particles who are popular products in many industries.

Normal Heavy Duty Polythene Bags with Heat-seal openings

The first one is normal heavy duty polythene bag (sacks) with heat-seal openings. This kind of PE bag can be used for fertilizer, polyester resin, animal feed, etc. This is a popular bag sealing technology which can prevent almost any forms of contaminants from entering the bag. And the film designed for such purposes are stronger than normal bags. Moreover, PE film itself has the performance of blocking air from 95% to 99% therefore along with the heat-sealing technology, the safety of the products inside can be guaranteed.

Square Bottom Heavy Duty Polyethene Bags with Heat-seal openings

As the name implies, this types of Heavy Duty Polyethene (PE) bag has a square design on the bottom. The design contributes to the storage of bag so that bags can pile up more easily and stand up in the warehouse, which saves a lot of storage spaces. In addition, it reduces the contac area of the bag to the ground by which to a certain extent reduces the risk of penetration by sharp objects. This kind of bag is designed for those products who require stand up in stead of.

Heavy Duty Polyethene Bags with valve mouth (valve Bags)

Another type of heavy-duty Polyethene (PE) Bag (sack) is valve bag whose name was given because it has a valve mouth on the top of the bag. As soon as the bag is full, the interior pressure of the bag closes the valve to stop product from spilling over. This kind of bag was first invented by Adelmer M. Bates, a salesman of salt from Chicago, The United States. Because of the self-closing feature, it reduced the labour required to fill and close the open mouth sacks.

This kind of bag has been used mostly on powdered product such as flours, activated carbon, cement and so on. Because they generate considerable amount of dust in the working environment which threatened the health of the workers. Hence, one of the most prominent advantages of the valve is the ability to reduce dust. Special machine was used for this valve bag so that the potential risk of dust is tremendously decreased.

Heavy Duty Polyethene Bags with Side Gusseted Feature

This feature is also called side fold, the side gussets expand when this package is filled with product – allowing for an ideal shape for filling, palletizing and retailing. This is a useful feature that not only gives the bag sense of beauty, but also increased its capacity so that it could load relatively more materials.

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Influence Factors of of Heavy Duty PE Bag

Temperature

The transportation of certain products will go through a series of different environment from dry to humid, from cold to hot and so on. How to make sure the bag could endure all the obstacles is an important issue for plastic bag manufacturer like us. Change of temperature is one of the key issues during the transportation stage. We have seen many precedents that neglect the factors of temperature which at last, caused great loss.

Professional plastic bag producer will ask you the transportation route and adjust their production. The basic property of PE film suggests that it will harden in a low temperature environment where the likelihood of breakage will increase. Whereas in the case of higher temperature environment, the film will soften when expose to heat. Both results will have a negative impact on the performance of the bag. Hence, adjustments will be made to the production of PE film in relation to the temperature condition. Other factors such as moisture, potential of exposure to sunlight, risk of puncture during transportation are all part of the responsibility for the plastic bag

Moisture

This is the issue that has troubled almost the whole supply chain from fertilizer producers to end users due to the complex humidity conditions in different regions. The need for a high barrier packaging can be vital to the protection of the product. Normally, the packaging material for fertilizer is made from polyethylene (PE) which provides higher barrier that prevent moisture from entering the bag.

In addition, the application of three-layered co-extrusion technology has even increased the ability of moisture proof by adding extra layer of plastic film to the bag. the test shows that PE bag produced by such technology has higher rate of moisture proof up to 30%.

Degassing Valve

Degassing valve is another interesting feature inspired by coffee packaging. Coffee beans will generate gases as time goes on therefore there will be a degassing valve added on the coffee pouches which enables it to exhaust gasses during transportation and reduce the potential expansion of bag. This idea is now applied to other industries such as fertilizer and animal feed who also generate gases.

Degassing valve is a useful design especially for agricultural products such as fertilizer, animal feed, feed additives, some plastic particles, grass seeds, soil and so forth. The reason is evident that such product is likely to produce gases during the transportation and the degassing valve allows for trapped air or gas produced by the fertilizer, seeds to escape the bag so that the bag doesn’t expand during the transportation. It can be dangerous if the bag swells up during the transportation. For instance, the burst of the bag, breakage of the bag, all of them will cause considerable, unnecessary loss of the products. Hence, the degassing valve is important in preventing such problems to occur especially during the transportation stage.

Anti-Skid Strips

This is the feature added on the bag to improve surface friction so that bags can stack more steadily as well as saving storage space during transportation. Fertilizer bags will be used multiple times by farmers and gardeners, while bags are crucial to the storage of fertilizer. Hence, to ensure the safe stack of the fertilizer, the anti-skid strip serves to stabilize every bag in the warehouse.

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Conclusion

When looking for heavy-duty plastic bags, waterproof, puncture, tear and chemical resistant are the major features you need to take into consideration. The abovementioned features are fundamental to a heavy-duty sack, but there are other customizations you could expect from PE bags with regard to the specific storage requirements of certain products. For example, some agricultural products require UV free environment where we could add extra layer of film so that making the bag become UV resistant. To get a sack you wanted most, you could contact us for more details. We SHU PACKAGING provides extensive range of heavy duty polyethene sacks which I believe one of them will suit your need.