Polypropylene Bag

Today, they are widely used in many applications, including reusable bags, automotive industries, and even furniture manufacturing. Polypropylene bags are one of the top three polymers used today. This type of plastic is one of the cheapest types of plastics, so it is extensively used in the production of reusable bags.

Polypropylene has two main types: homopolymers and copolymers. However, for most people unfamiliar with chemistry or not involved in the polypropylene bag industry, this difference is not very important. But the important point is that two types of polypropylene materials are used to produce reusable bags: woven and non-woven. Woven bags are made from polymer fibers that are cross-woven to form sheets. Non-woven bags take these fibers and process them under heat and pressure to create a bonded, wax-like sheet. Both types of materials are resistant and sturdy, but woven polypropylene bags have edges and are therefore usually used in packaging heavy items like sand bags.

Don’t forget to check the structure (heat-sealed seams) and grams per square inch (GSM) when comparing polypropylene bags. The higher the GSM, the thicker and sturdier the bag.

One important advantage of polypropylene bags is their recyclability. Yes, polypropylene bags can be recycled! For this, their materials are melted at very high temperatures to remove impurities. Recycled polypropylene materials can be mixed with virgin materials up to 50%, but most reusable bags contain only 20% recycled materials. Compared to other materials, polypropylene bags have more advantages. One of the major advantages of polypropylene bags is their recyclability. Yes, polypropylene bags can be recycled! To recycle polypropylene bags, materials are melted at very high temperatures to remove impurities. Recycled polypropylene can be mixed with virgin materials up to 50%, but most reusable bags contain only 20% recycled materials.

Advantages of Polypropylene Bags

Polypropylene is a highly popular material in bag production due to its high moldability and unique properties. This popularity stems from its highly “moldable” nature. Adaptability, a wide range of applications, and its unparalleled characteristics are among the reasons for this.

The melting temperature of polypropylene is relatively low, allowing it to change shape under heat. This feature requires a high level of skill for producing thick bags. Additionally, these bags have excellent resistance and are lightweight. Typically, they can withstand temperatures up to 110 degrees Celsius.

Polypropylene bags are created using a process of melting and weaving. Initially, the plastic is melted at very high temperatures and then molded into long strips. These strips are then woven to create a sturdy plastic structure. The sheets are then cut and formed into bags. These woven bags offer a combination of excellent resistance and lightweight, making them ideal for various industries.

Due to their numerous features, polypropylene bags are used extensively. These bags are non-toxic, have a high operational temperature, are resistant to various weather conditions, stain-resistant, and easy to clean. If coated with a laminate layer, their resistance to water and waterproofing also increases.

The melting temperature for producing polypropylene bags can range anywhere from 200 degrees Celsius (392 degrees Fahrenheit) to 250 degrees Celsius (482 degrees Fahrenheit), although it can go higher depending on the grade of polypropylene and the type of additives present. Shrinkage in polypropylene is approximately 1%, but it can vary based on various factors including holding pressure, holding time, melting temperature, mold wall thickness, mold temperature, and the percentage and type of additives.

Some notable features of this polymer include scratch resistance to nails and resistance to breaking, but if subjected to excessive flexural stress, it whitens.

The general characteristics of polypropylene bags include the following:

High resistance to acids, alkalis, and fats.

Affordable price.

Ease of molding for injection molding and acceptable fluidity in molds.

Capability to mix with fillers such as sawdust and create composites.

Relative non-toxicity and suitability for making toys and children’s items.

Availability and non-strategic nature of the product.

Production of raw materials by domestic factories.

Excellent colorability with various masterbatches.

Heat sealability.

Recyclability.

Ability to combine with cores and metal bushings during injection.

Polypropylene plastic is commonly used in industrial design in one of the following forms:

Structural and non-transparent (matte or glossy).

Structural and semi-transparent (usually gray and non-glossy).

BOPP film.

OPP or CPP film.

In addition to granules and sheets, polypropylene plastic is also available in film form. These films are generally produced in two main types: BOPP and OPP or CPP.

BOPP, or biaxially oriented polypropylene, means that during production, in addition to extruding the layer in a cascade manner, it is also stretched from the sides, which provides greater dimensional and thermal stability during printing and packaging compared to the second type, OPP or CPP. The main applications of polypropylene films are in the production of flexible packaging such as chip, snack, biscuit, ice cream, pasta, and similar products, which can be used laminated, single-layered, metallized, etc. Polypropylene plastic is easily identifiable due to its visual, auditory, and tactile properties. For example, products made from polypropylene differ in shape, appearance, sound, and tactile sensation from other products, giving them a high identification advantage.

How are polypropylene bags produced?

Polypropylene bags are made by melting plastic at extremely high temperatures. It is then molded into long strips, which are then woven to create a sturdy plastic mesh. These woven polypropylene sheets are cut and stitched into bags. You can see the image of polypropylene strips woven into sheets. Woven polypropylene bags offer an excellent combination of lightweight bags with excellent resistance, making them ideal for use in various industries such as food, construction, and recycling.