How Shore Hardness Affects Silicone Properties – A Practical Guide to Material Selection
Shore hardness is one of the key parameters that must be considered when selecting silicone products. It largely determines the functional properties, durability, and application potential of the material across various industries. What exactly is Shore hardness? Why is it so important for the quality and performance of silicone products? In this article, you will find all the essential information regarding hardness measurement and its practical significance in industrial applications.
What is Shore hardness and how is it measured?
Shore hardness defines the resistance of a material to indentation by a standardized indenter. The measurement is performed using a device called a durometer. During testing, a probe with a defined shape and applied force presses against the silicone surface. The smaller the penetration depth, the higher the Shore hardness.
This parameter is particularly important for elastomers, as it is directly related to key material properties such as:
- elasticity
- elongation
- resistance to deformation
- mechanical stability
For this reason, Shore hardness is one of the primary criteria for selecting the appropriate type of silicone for a specific application.
Shore hardness scales used in silicones
Various Shore scales are used to measure elastomer hardness, but for silicone, the most commonly used is the Shore A scale, intended for soft and medium-hard materials.
Main scales:
- Shore 00 – for very soft materials
- Shore A – standard scale for silicones and soft elastomers
- Shore D – for harder plastics (rarely used for silicones)
Typical silicones range from Shore A10 (very soft) to Shore A70 (hard). The selection of appropriate hardness depends on the requirements of the specific application.
How Shore hardness affects silicone applications
Choosing the correct Shore hardness directly impacts the functionality and durability of silicone products. Depending on hardness level, the following applications can be distinguished:
Soft silicones (Shore A10–A25)
Used in applications requiring high flexibility and gentle surface contact, including:
- medical applications
- skin-contact products
- food-grade silicones
- seals with high deformation capability
Medium hardness silicones (Shore A25–A50)
Most commonly selected for technical applications such as:
- silicone hoses
- profiles and seals
- components requiring moderate flexibility and stability
They provide a good balance between flexibility and strength.
Hard silicones (Shore A50–A70)
Used where higher mechanical resistance is required, including:
- machinery industry
- automotive industry
- electrical engineering
- construction
How to ensure reliable Shore hardness measurement – key principles and quality control
To obtain reliable and comparable results, hardness measurement must be performed under strictly controlled conditions. Key factors include:
- stable base
- constant temperature, as silicone reacts to thermal changes
- standardized measuring device
- repeatable testing procedure
Maintaining these conditions ensures that hardness values are objective and compliant with standards.
International standards for Shore hardness measurement
Shore hardness measurement is performed in accordance with international standards such as:
- DIN 53505
- ASTM D2240
These standards ensure global comparability of results and define requirements for equipment, procedures, and calibration.
Silicone in various Shore hardness ranges available at PowerRubber – how to choose the right one?
Shore hardness is one of the most important parameters influencing the durability, functionality, and behavior of silicone in practical applications. The PowerRubber range includes silicones with a wide spectrum of hardness levels — from very soft to hard technical grades. This allows precise material selection tailored to specific application requirements.
If you need assistance in selecting the appropriate Shore hardness, it is worth consulting Power Rubber specialists.
Please contact us at +48 22 292 40 24 or +48 505 16 03 03, or via email (Power@PowerRubber.com) or our contact form.