Compounds

Compound is a combination of polymer materials such as various grades of polyethylene and such, which is added to raw materials in order to increase physical, mechanical and thermal properties. These compounds are generally produced in the form of granules and used in the composition of various polymer products. In other words, the compound includes a mixture of several types of polymer bases with additives to improve the structure and properties of the manufactured product.

Why do we use compounds?

Sometimes, when producing some polymer products, manufacturers face problems such as weak physical properties, reduced properties, undesirable color, etc. As a result, the masterbatch cannot be used due to product incompatibility. In these cases, by adding materials such as compounds during the plastic injection and extrusion process, they strengthen the chemical properties and reactivity of the product. From the economic and health point of view, the use of compounds in the production of polymer products is more economical than masterbatch types. Because the compound does not have the side costs of cleaning and compounds in using the masterbatch.

Polyethylene compound

Polyethylene compound is one of the most important and practical types of compounds, which is widely used in the production of polyethylene pipes for water supply. This type of compound consists of a series of industrial waste and other chemical materials, which has properties such as high resistance to direct sunlight and various mechanical impacts. The mentioned compound, while having an ideal quality, has a reasonable price; For this reason, it has the ability to compete with similar foreign markets. In the following, we will examine the most important grades of polyethylene compound.

Low-density polyethylene (LDPE)

This polyethylene has low tensile strength, and its other characteristics include flexibility and the possibility of decomposition by microorganisms.

Medium density polyethylene (MDPE)

It is a special type of polyethylene that is between heavy polyethylene and light polyethylene in terms of polymer structure and density. Most medium density polyethylene has a linear structure and have special applications such as the production of large tanks for water storage, etc.

Linear light polyethylene (LLDPE)

Linear light polyethylene is obtained by adding normal butene comonomer to ethylene during the polymerization process. Linear light polyethylene has superior mechanical properties compared to light polyethylene, for example, by adding it to light polyethylene, polymer films with higher strength and tensile strength can be produced.

Heavy High-Density Polyethylene (HDPE)

This polyethylene has higher tensile strength than other polyethylene.

Ultra-high molecular weight polyethylene (UHMWPE)

Polyethylene with a molecular weight between 3 and 6 million is called ultra-high molecular weight polyethylene or UHMWPE. Polyethylene with a very high molecular mass is used in other cases such as making resistant pipes in the oil and gas industry, waste discharge pipes, etc.

Polypropylene compound

Polypropylene compound is another type of compound used in the production of polymer products that has a composite structure. After polyethylene, this compound is one of the most widely used compounds. This type of compound is used in the manufacture of car parts, the production of household appliances and plastic items used in kitchens, and the preparation of pipes and fittings.

Differences between polyethylene and polypropylene compounds

As we saw in the previous section, two of the most common types of polymer compounds are polyethylene and polypropylene compounds. In this section, we want to point out the differences between these two types. In the following, we point out the main differences between them.

Polypropylene is easier to produce than polyethylene.

Polypropylene is more rigid than polyethylene.

The chemical resistance of polypropylene against organic solvents, acids and electrolytes is higher than that of polyethylene.

The resistance to cracking of polypropylene is high, but polyethylene has somewhat higher elasticity and flexibility.

The printability of polypropylene films is higher than that of polyethylene.

Compound production process

The compound is produced during complex and long steps in the chemical industry. The first stage of its production is the melting of raw materials, which is done by a machine called an extruder. In this way, first the powder mixture of basic polymers and additives enters the extruder and after melting, it comes out of the die located at the end of the machine. In the next step, the molten material is cooled and frozen during the cooling process and ready to be cut.

What is the difference between compound and masterbatch?

The type of molecular structure of compound and masterbatch are somewhat similar to each other, and their difference is in the behavioral reaction, the percentage added to the final products, and their use in various manufacturing industries. That is, when in plastic injection extruders and the production of polymer films, there is no possibility of a strong reaction between the masterbatch and polymer raw materials, the compound is used.

Engineering polymer compound

Engineering compounds are used in the manufacture of engineering polymer products with a special design and suitable for specific usage conditions. This compound is used to increase mechanical strength, resistance to all types of abrasion, chemical acids and bases. Polymer products produced by plastic injection and extrusion methods, by adding engineering compounds, have a longer lifespan. Engineering compound production centers produce these compounds according to the customer's and user's needs.

Compound reinforced by glass fibers

These compounds have high mechanical and thermal properties. This type of compound is widely used in various automotive, household appliances, electrical and electronic industries. This type of compound is mostly used in products that are covering and insulating.

Rheological cleaning compounds

Due to their rheological properties, these compounds are used in the cleaning operations of cylinders, mandrels and dies in extruders. The mentioned compound is used in the production devices of polymer products such as polyethylene films, sheets, tubes and cardboard plastics. The cleaning compound has the ability to remove any impurities and discoloration in the shortest possible time. In the extrusion process using a cleaning compound, the amount of waste produced is very low, which is a positive point about rheological compounds.

Filling compounds

The filling compound is produced based on different percentages of filler and according to different polymer bases. The type of structural formula used in this type of compound, besides creating excellent properties in polymer products, also reduces the final price of the product. The mentioned compound is used in extrusion, plastic injection and thermoforming processes.