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Key points of this article
- The four main causes of hose hardening are heat, chemicals, oil, and UV rays.
- These factors dissolve the plasticizers in PVC resin and break down bonds, resulting in hardened hoses.
- To extend the life of hoses and prevent problems, hoses should be selected according to the fluid, temperature, pressure, and other operating conditions.
Why Do Soft Hoses Harden?
Now, here’s a question for you from Hose Adviser Pro.
Which of the following causes hoses to harden?
Select from among A, B, C, and D below.
A. Heat
B. Chemicals
C. Oil
D. UV rays (sunlight, etc.)
The correct answer is all of the above.
Did you answer correctly?
There are four main causes of hoses becoming hardened.
1. Heat
2.Chemicals
3.Oil
4.UV rays (sunlight, etc.)
Polyvinyl chloride (PVC) resin is often used to make general-purpose hoses. Although PVC resin itself is hard at room temperature and can’t be bent, the PVC used in hoses is known as soft PVC resin and keeps the hose flexible. This flexibility comes from plasticizers added to the resin. As a result, PVC hoses remain flexible and easy to handle at room temperature.
However, when exposed to heat, chemicals, oil, or UV rays, PVC hoses may degrade. These factors can dissolve plasticizers or break down the PVC structure, causing the plasticizers to be lost. When plasticizers are lost, the PVC hose becomes stiff and may lead to a variety of problems.
Selecting the Right Hose to Prevent Hoses from Hardening
Hoses are available in many types, and it is important to select a hose that matches the operating conditions, including fluid being used, temperature, and pressure. Below are recommended hose materials based on each cause of hardening. To learn more about countermeasures for each cause, register on the Toyox website to download additional technical resources.
[Heat]
Hoses made from a heat-resistant material such as silicone rubber are highly effective for high-temperature fluids. Long-term use or storage in strong sunlight or high-temperature environments may also lead to discoloration and, in severe cases, the plasticizer in PVC resin may leach out, causing the hose to harden. Pay close attention to both the operating environment and storage conditions.
[The following technical resources are recommended for anyone interested in learning more about preventing problems.]
Solving Heat-Related Hose Problems
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[Chemicals]
Non-PVC polyolefin resin and fluorine resin hoses are often used for chemicals thanks to their high chemical resistance, and chemical-resistant stainless steel or resin couplings are also often used.
[The following technical resources are recommended for anyone interested in learning more about preventing problems.]
Solving Chemical-Related Hose Problems
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[Oil]
For oil, selecting a PVC hose with excellent oil resistance or a hose that uses an alternative material to PVC such as fluorine or polyolefin is recommended.
[The following technical resources are recommended for anyone interested in learning more about preventing problems.]
Solving Oil-Related Hose Problems
Register as a member to access this download.
Register on the Toyox website to access over 70 resources on hose and coupling troubleshooting and useful tips.
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That concludes our look at the causes of hose hardening and the key preventative points.
For any other inquiries or consultations, please contact the Toyox Customer Service Office.
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Hoses harden over a short time, requiring frequent replacement...
Hoses left unused become hard and must be replaced with new ones...
Have you ever experienced these kinds of problems from hardened hoses?
Once a hose hardens, it cannot be returned to its original condition and may cause various types of problems, so replacement is recommended as soon as possible. In this article, Hose Adviser Pro explains the causes behind hose hardening and how to prevent it.