BS ISO 29664:2010 pdf free download Plastics — Artificial weathering including acidic deposition
1 Scope
This International Standard describes artificial weathering tests intended to evaluate plastics for use in heavilypolluted outdoor environments.Results from this International Standard cannot be used to predict the serviceiife of these plastics.
This International Standard describes two different exposure methods.Use of the methods depends on theform of the plastic product being evaluated.
Method A is intended for products where surface degradation is very important and uses a strong acid spray(pH 1,5) that is applied for a short time.
Method B uses a weaker acid spray (pH 3,5) that is applied over a long period of time so that it can penetratedeeply into the product and is intended for products such as geotextiles and related products.
This International Standard does not cover the influence of special chemicals like agrochemicals.
2Normative references
The following referenced documents are indispensable for the application of this document. For datedreferences,only the edition cited applies. For undated references,the latest edition of the referenceddocument (including any amendments) applies.
ISO 291, Plastics —Standard atmospheres for conditioning and testing
IS0 4582,Plastics — Determination of changes in colour and variations in properties after exposure todaylight under glass, natural weathering or laboratory light sources
ISO 4892-1, Plastics — Methods of exposure to laboratory light sources — Part 1: General guidanceISO 4892-2, Plastics — Methods of exposure to laboratory light sources— Part 2: Xenon-arc lampsISO 4892-3,Plastics — Methods of exposure to laboratory light sources— Part 3:Fluorescent UV lamps
3Principle
The combined action of UV radiation, heat, humidity, wetting, and acidic deposition is evaluated in weatheringdevices conforming to lSO 4892-1,ISO 4892-2 and iSo 4892-3.
The acidic deposition, in some cases, may accelerate the degradation of the polymer itself. In other cases, thedegradation is accelerated when the acid deposition attacks the stabilizers in the polymer.
Two different methods combine acidic deposition with artificial weathering. In method A, a strong acid solutionis applied once per day. In method B, a weaker acid exposure is integrated in the rain phase.
two procedures, one intended to simulate very humid climates such as those in tropical or subtropical areas and one intended to simulate more moderate, less humid climates. As this mechanism does not depend on the size of the damage spots, either horizontal or vertical specimen orientation is allowed (see A.3).
Use of reference materials is recommended in order to monitor the consistency and repeatability of the test. Suited sets of reference materials may be samples with different grades (good, moderate, low performance) based on previous tests using the same method. The reference material selected shall be stable when stored in the dark at room temperature.
4 Apparatus
4.1 General apparatus, including two types of weathering devices conforming to ISO 4892-2 and ISO 4892-3. The test chambers, as well as all required mounting devices and holders, shall be made of acid- and UV-resistant materials. NOTE As both types of weathering devices show a different spectral distribution, the results can differ.
4.2 Artificial acidic deposition, to produce an acid mixture of pH 1,5 at (25 ± 2) °C, add 10,6 g of H 2 SO 4 , 3,18 g of HNO 3 and 1,80 g of HCl to 10 litres of deionized or distilled water. This yields a mass ratio of 1,0:0,3:0,17. The quantity of acid to be added assumes that the concentration is 100 %. Since the actual concentration of the reagent grade If required, a solution with a pH of 2,5 can be produced by diluting the pH 1,5 solution with demineralized water in a volume ratio of 1:10.
The solution with a pH of 3,5 is prepared by diluting the pH 1,5 solution with demineralized water in a volume
ratio of 1:100.
Check the pH of the acid solution before starting the test. If the pH is more than 0,3 units away from the desired pH, discard the solution and make a fresh batch.
Store the acid solution in a sealed container to avoid changes in pH during storage.
4.3 Laboratory radiation sources.
4.3.1 Fluorescent UV lamp apparatus, conforming to ISO 4892-3 with Type 1A lamps specified in ISO 4892-3, if used.
4.3.2 Xenon arc lamp apparatus, conforming to ISO 4892-2, equipped with daylight filters as specified in ISO 4892-2, if xenon arc apparatus is used.
Irradiance uniformity shall be in accordance with the requirements specified in ISO 4892-1.