Reasons for Deviations in TPE Material Hardness
Time of issue:2025-07-23
TPE is a non-standard composite polymer material. In the process of new product development, the selection of TPE materials requires sample testing to determine the appropriate TPE grade. For a TPE grade, hardness is the most basic parameter. It is crucial to accurately control the hardness of TPE materials before providing samples to customers. However, in practice, there are often significant differences in hardness between the samples we provide to customers and the material hardness required by them. What causes this? Below, SuBo will share the reasons for hardness deviations.
Reasons for inaccurate hardness of TPE materials:
1. The customer has no sample and only knows the material hardness
In fact, the hardness provided by the customer may not be accurate. There may be problems with the way the hardness data is obtained. This situation is not uncommon in the actual TPE material confirmation process.
2. The customer has no sample, and there are problems with the unit of the provided hardness value
There is more than one common hardness unit for soft rubber. Soft PVC uses "P" to represent hardness, TPE is usually expressed in "A", and harder TPE is expressed in "D". But customers usually just say "how many degrees". In this way, sometimes the hardness may be wrong due to confusion in the expression unit. This requires sales personnel to be careful when communicating with customers to accurately understand their hardness requirements.
3. The customer has provided a TPE sample, but it is difficult to accurately measure the hardness of the sample
Hardness measurement requires a flat test piece with a thickness of about 6.35mm for more accurate results. However, in most cases, the samples provided by customers are curved and non-flat, and their thickness is relatively thin. This makes it difficult to accurately determine the material's hardness. Experienced TPE material engineers can control the difference between the measured hardness and the actual hardness within 3-5 degrees. If the sample is thick, close to the thickness of the test piece, and the surface is relatively flat, the sample can be measured more accurately.
4. The customer has no sample, and the method of expressing hardness is inconsistent with that of the supplier
There are two methods for testing TPE hardness: delayed reading and immediate reading. Immediate reading refers to reading the hardness as soon as the hardness tester's pointer presses on the test piece. Delayed reading means reading after keeping the pointer pressed on the sample surface for a period of time (usually about 5 seconds). Generally, the delayed reading is softer than the immediate reading. However, the hardness difference is usually within 2-5 degrees (A), and the softer the material hardness, the greater the test difference.
5. Improper production and processing by the supplier, resulting in the sample hardness failing to meet the customer's requirements
This situation is relatively rare, but in some small companies, if management is not standardized and operations are not careful, the quality and proportion of certain components in the compounding process may be controlled inaccurately. This leads to the hardness of the produced TPE samples not meeting the standards. It requires operators to strengthen their sense of responsibility to eliminate such problems.
TEL: +86-0752-6768128 FAX: +86-0752-6768088 MAIL: sales@tpe-sp.com WEB: en.tpe-sp.com
ADD: Huangxi Industrial Park, Shiwan Town, Boluo County, Huizhou City, Guangdong Province，China