What Is Chemical Resistance?
Chemical resistance test is a test in which the sample is immersed in a defined chemical liquid at a defined temperature and time; It is an experiment in which the change in mass, size, appearance and mechanical properties is measured.
Purpose of Chemical Resistance
The aim is to verify that the material retains its properties against chemicals in the service environment.
Which Products Is Chemical Resistance Applied To?
- Chemical plant pipe and tank materials
- Automotive engine compartment parts
- Gaskets and sealing elements
- Coatings and primers
In Which Sectors Is Chemical Resistance Used?
Standards Related to Chemical Resistance
- ISO 175
- ASTM D543
- ISO 4599 (under tension)
- ISO 22088 (environmental stress cracking)
Chemical Resistance Conditions
- Kimyasal
- Liquid representing the service medium; defined in specification
- Temperature
- Service temperature or accelerated temperature defined in the standard
- Time
- Defined in the standard; typically days to weeks
- measured change
- Mass, size, hardness, appearance and tensile properties
Equipment for Chemical Resistance
- Dip pots and temperature-controlled baths
- Analytical balances and measuring instruments
- Tensile tester (post-exposure)
- Fume hood and chemical storage
Sample Requirements for Chemical Resistance
- Sample dimensions and surface condition must comply with the standard
- All measurements should be recorded before exposure
- Control samples (unexposed) should be kept together
- Chemical freshness and concentration should be monitored
Duration of Chemical Resistance
1–6 weeks depending on duration.
Chemical Resistance Procedure
- 1Samples are measured and weighed.
- 2The chemical is prepared and brought to temperature.
- 3Samples are immersed for a defined period of time.
- 4Samples are removed, cleaned and conditioned.
- 5Mass, size and appearance change are measured.
- 6Mechanical properties are measured again and compared to the control.
Chemical Resistance Acceptance Criteria
Acceptance criteria are given in the specification: mass/size change and loss of mechanical properties remain below the limit.
Evaluation of Results
Increasing the temperature may change the mechanism; The accelerated test result cannot be directly translated into service life. Circumferential stress cracking in material under tension develops much more rapidly than in stress-free immersion; If there is this risk, ISO 22088 type testing is required.
Chemical Resistance Report
- Standard applied
- Chemical, concentration and temperature
- Exposure duration
- Before/after measurements and control comparison
- Appearance findings
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Product and facility specifications
Rubber Testing — What Does This Testing Field Cover?
The section below describes the field that the Chemical Resistance test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Rubber testing determines the mechanical behaviour of an elastomer and its resistance to environmental effects. Elastomers are assessed with a different logic from metals and plastics: the real question is not strength but ELASTIC RECOVERY and ageing behaviour.
The function of an elastomer is usually to deform and return: a gasket is compressed and provides a seal, a mount absorbs vibration, a hose expands under pressure. What is measured in the field is therefore not "how many newtons does it withstand" but "how far does it recover after deformation, and how long does it keep doing so".
COMPRESSION SET is therefore the most decisive measurement in the field. If a gasket cannot recover after being held compressed for a long period, it has lost its sealing function even though it has not torn at all. This measurement is made together with temperature, because permanent set increases rapidly with temperature.
Hardness is the most common measurement in the field, using the Shore A and IRHD scales. It is fast and practical but does not define the material on its own: two different compounds of the same hardness can show completely different ageing and fluid resistance. Hardness is valuable in monitoring compound consistency.
On the environmental resistance side, hot air ageing, swelling in fluids, ozone cracking and low temperature behaviour are examined. FLUID RESISTANCE is particularly critical: the same elastomer behaves differently in fuel, oil, coolant and brake fluid — swelling in one, shrinking in another, hardening in a third. The material is therefore tested with the actual fluid it will contact and at the actual temperature.
Ozone cracking is a silent cause of failure in parts used outdoors. Low concentrations of ozone in the atmosphere create surface cracks in unsaturated elastomers under strain; the part cracks while appearing to carry no load at all. An ozone chamber accelerates and reveals this behaviour.
Low temperature behaviour is the second silent risk. As an elastomer approaches its glass transition temperature it loses elasticity and behaves like a rigid plastic; a gasket starts to leak in the cold. Low temperature recovery and brittleness tests establish this limit.
A change of compound is not a silent change in this family. When filler content, plasticiser or the vulcanisation system changes, mechanical properties and fluid resistance shift together; verification is repeated.
Method groups in this field
Mechanical
Tensile stress-strain properties, tear strength, abrasion (rotating drum and Pico), fatigue and tear propagation.
Hardness
Shore A and IRHD indentation hardness; a rapid indicator of compound consistency.
Permanent deformation
Compression set and stress relaxation; decisive for sealing components.
Fluid resistance
Swelling in fuel, oil, coolant and chemicals, change in mass and volume, loss of hardness and strength.
Ageing
Hot air ageing, ozone cracking, the effects of UV and humidity.
Low temperature
Low temperature recovery, brittleness temperature and flexibility measurements.
Commonly confused in this field
- Hardness does not define the material; two compounds of the same hardness can show different ageing and fluid resistance.
- Fluid resistance must be tested with the actual fluid and the actual temperature; a general claim of oil resistance is insufficient.
- Without measuring compression set, no decision can be made about sealing life.
- Ozone cracking occurs under strain; a test with an unstrained specimen does not show the real risk.
- A change of compound requires verification to be repeated; a supplier may change its compound silently.
- A gasket whose low temperature behaviour is not stated produces unexpected leaks in cold climates.
Which decisions these results support
- Material selection for gaskets and sealing components
- Automotive and industrial component approval
- Verification of a compound change
- Root cause analysis of field leaks and cracking
- Declaration of the operating temperature range and fluid compatibility
Related Tests
Frequently Asked Questions About Chemical Resistance
According to which standard is Chemical Resistance made?
Chemical Resistance is executed in scope ISO 175, ASTM D543, ISO 4599 (under tension) and ISO 22088 (environmental stress cracking). The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Chemical Resistance apply to?
Mainly applied to Chemical plant pipe and tank materials, Automotive engine compartment parts, Gaskets and sealing elements and Coatings and primers. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Chemical Resistance done?
The determining parameters are: Kimyasal — Liquid representing the service medium; defined in specification, Temperature — Service temperature or accelerated temperature defined in the standard and Time — Defined in the standard; typically days to weeks. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Chemical Resistance?
Sample dimensions and surface condition must comply with the standard, All measurements should be recorded before exposure and Control samples (unexposed) should be kept together. The number of samples is determined according to the product standard and the scope to be reported.
How long does Chemical Resistance take?
1–6 weeks depending on duration. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Chemical Resistance result called "appropriate"?
Acceptance criteria are given in the specification: mass/size change and loss of mechanical properties remain below the limit.