HIPS Hardness is one of the parameters that determine quality. High impact polystyrene is resistant to pressure and impact; This material is used to make durable plastics. There are several ways to measure HIPS Hardness. These methods are the Rockwell method and the Shore method.

methods are different and are used to determine the hardness of HIPS polystyrene. In general, different standards have been set for these methods, which we review in this article. Stay tuned to PETROPROVIDERS for the rest of this article.

The precise definition of HIPS Hardness

Hardness is known as a very important parameter in increasing the strength of polystyrene materials. This parameter indicates whether the material is scratched in front of different objects. For example, if we put two materials together, each material that is scratched is less difficult.

In this example, the hard object enters the softer body and creates pressure. This pressure changes the structure of the softer material and a line of hard material is drawn on the soft material. That is, our experiment was performed with two different substances.

Various factors affect the severity of HIPS. These factors include:

  • Polystyrene raw materials
  • Additives of this substance
  • Methods of making this polymer
  • HIPS polystyrene molding method
  • Standards set when making this polymer
  • ..

In general, determining the hardness of a material is a simple experiment. This is done using standards. It is interesting to know that hardness does not have a specific unit! Parameters such as needle penetration, abrasion resistance, and scratch resistance can be used to express HIPS Hardness.

HIPS Hardness test steps and its methods

HIPS Hardness test steps

HIPS Hardness test steps

As mentioned, there are two ways to determine the hardness of polymers. Determination of hardness is one of the main tests to determine the physical and chemical properties of materials. In this test, there are set standards that must be met at all stages. These tests are generally based on the penetration of one substance into another.

If a hard substance is applied to another substance, a trace of this substance remains on the softer substance. It depends on the geometry of the materials as well as their constituents. If material is pulled on another material with three-way pressure, it causes the material to deform softer.

This test is very simple and therefore easy to perform. In addition, this test is performed all over the world and in different laboratories and does not require special tools.

As mentioned, there are two main ways to determine HIPS Hardness. The Rockwell test and the Shore test are two interesting methods for measuring the hardness of polystyrene materials. These methods are used for certain materials and have certain standards.

The different parameters in these two methods are different. For example, needle material, penetrant material, amount of force applied, reaction time, type of soft material, and hardness measurement. In the continuation of this article, we will see different methods of measuring hardness in polymers.

Introduction of hardness test, Rockwell method

This method is usually used to test plastics such as polystyrene, nylon, and polycarbonate. This test must be performed by ASTM D785 and ISO 2039 standards. In this test, a penetrant is a conical object. The material of this material can be diamond or steel.

To perform this test, first, for 10 seconds, the penetrating body forces the HIPS sample. Then, more force is applied to the sample for 15 seconds and this object penetrates the sample to some extent.

In this method, 3 main methods can be done with different parameters. These 3 methods are method M, method R, and method E. For example, in method R, the force is between 10 to 60 kg and the diameter of the needle is about half an inch. Other methods of this test are:

  • In the M method, a force of 10 to 100 kg is applied and the diameter of the needle is about a quarter of an inch.
  • In Method E, a force of 10 to 100 kg is applied and the needle diameter is about 0.125 inches.
  • In the L method, a force of 10 to 60 kg is applied and the diameter of the needle is about a quarter of an inch.
  • In the K method, a force of 10 to 150 kg is applied and the needle diameter is about 0.125 inches.

Introduction of hardness test, Shore Durometer method

This method is one of the most common methods for measuring hardness; Because the equipment needed to perform this test is lightweight and portable. This includes two methods, A and D. In method D, the needle is in the form of an incomplete cone, but in method A, the tip of the needle is spherical. These needles must penetrate the sample.

Method A in the Shore method is used to determine the hardness of soft plastics such as PVC and soft rubbers. Therefore, this method can not be used to determine the hardness of HIPS polystyrene.

Method D is used to determine the hardness of rigid plastics; So we can use this method to determine the hardness in HIPS polystyrene.

In general, this method must be performed by ISO 868 and ASTM D2240 standards. These standards specify that the force is applied to the material by a spring and that the amount of sagging depression is measured. This test requires a variety of equipment, such as a hardness tester, stopwatch, HIPS sample holder, and force weights.

According to the ISO standard in this method, the thickness of the HIPS sample must be at least 4 mm. According to the ASTM standard, in this method, the thickness of the sample must be at least 6 mm. To measure HIPS hardness, the sample should be placed on a horizontal surface.

The hardness tester is then placed at a distance of 9 mm and perpendicular to the sample. The force base does not hit the specimen but moves upwards at a high speed. It is then placed on the sample and pressed against it.

This step takes 15 seconds. The test needle is then placed on the sample and pressed against it. This step also took 15 seconds.

The average HIPS pressure and tolerance as well as the needle penetration should then be measured. These parameters are recorded and the experiment is completed.

Summary of HIPS hardness tests

HIPS sheets uses

HIPS sheets uses

In this article, we saw the measurement of HIPS hardness and its methods. There are several ways to measure HIPS Hardness. These methods are the Rockwell method and the Shore method. These methods are different and are used to determine the hardness of HIPS polystyrene.

In each method, different methods are used for different materials. These methods have special conditions and have different applications for different materials. The best way to measure HIPS hardness is to use the Shore method. In this method, ISO and ASTM standards must be observed.

To produce high-quality products, it is necessary to measure the specifications of polystyrenes. What do you think about measuring HIPS Hardness? Is this method sufficient to accurately determine the strength of polystyrenes? Are there standards for performing these procedures safely?

You can ask your questions in the comments section of our experts. To buy the best polystyrene, you can contact us or email us.