Instruments used to measure temperature, sample temperature, relative humidity, rainfall, wetting time, and illumination time should be compatible with the exposure method used and should be agreed upon by the parties involved.

Note: Wetting time is usually determined by using a primary battery or similar electrical method.

Specimen: Shape and preparation: The dimensions of the specimen shall be in accordance with the relevant test methods or the properties to be measured after exposure, unless it is required to take the specimen from the specimen exposed in sheet or other shape for the specified test.

If the material to be tested is a granulated, flaked or other initial state of extrusion or molding mixture, it shall be directly processed into a sample by a suitable method, or processed into a sheet by a suitable method, and then cut from the sheet. Take the sample.

The method used should be agreed by the relevant parties and should be closely related to the material processing method used by the user.

See sample GB/T9352, GB/T17037.1, GB/T17037.3, GB/T17037.4, GB/T11997, IS0294.2 and IS0294.5 for sample preparation.

If the material to be tested is an extrusion, molded part or sheet, etc., the sample may be taken from the material before or after exposure, depending on the specific test requirements and material characteristics.

For example, materials that are significantly embrittled after aging should be exposed in the shape being tested because processing is difficult after exposure; conversely, if the laminate is layered at the edges, it should be exposed in the shape of the sheet and the sample should be taken after exposure. 

Note: For the preparation of samples by mechanical processing, see IS02818.

When it is necessary to determine the aging behavior of a particular type of crystal, the product itself should be exposed whenever possible.

A portion of the product or product that is large enough for the test should be exposed in its own shape. For the first time the material is exposed and then the sample is removed from it, the exposed surface should not be removed during sample preparation. The specimen taken from the exposed sheet should be at least 20 mm from the edge of the sheet and the support of the clamp or non-simulated actual conditions.

No part of the exposed surface of the material should be removed during sample preparation.

Only samples of the same size and approximately the same exposed area should be compared.

Number of specimens: The specimens for each test condition or exposure period shall be at least the same as those specified in the relevant test methods for post-exposure performance tests.

Note: For mechanical performance testing, it is recommended that the number of exposed samples be twice the requirements of the relevant national standards (it is known that large standard deviations occur in plastic mechanical properties tests after aging).

The total amount of sample will be determined by the amount necessary to test the initial value and the performance value after each exposure cycle.

Condition adjustment and storage: If the sample needs to be prepared by machining and it needs to be pretreated for ease of preparation, the details of the pretreatment should be recorded.

Before the test, the sample shall be properly adjusted according to the type of material and the test method to be used; the process of state adjustment shall be recorded in accordance with the provisions of GB/T2918.

If the state adjustment period used is less than the minimum period specified in GB/T2918, the status adjustment period should be recorded as this will seriously affect subsequent test results (eg, the test sample is very sensitive to humidity and/or the sample is exposed) Situation of extreme weather conditions).

The reference sample should be stored in the general laboratory environment protected from light. It is best to use one of the standard environments given in GB/T2918.

Note: Some materials, especially aged materials, will change color during storage in the dark.