Weather Resistance

AATCC TM186-2000 pdf free.Weather Resistance: UV Light and Moisture Exposure.
8.1 The test cycle is best determined bythe influencing factors of the end use, in particular, the climatic conditions.Not allmaterials are affected equally by the same environment. Results obtained bythe use of any one test cycle may not berepresentative of those of any other testcycles or any outdoor weathering test.Any acceleration factor derived for onegeographic location does not necessarilyapply to any other geographic location.”However, certain test cycles are sug-gested to group similar climates with respect to the test cycle.
8.2 The nature of the test material con-tributes to the selection of the appropriatetest cycle with respect to Uv exposure, wetting, wet time and temperature.Thefollowing test cycles options have beenused for textile materials.
8.2.1 Option 1,General Applications:8 h UV at an irradiance of o.77 W/m 2 @340 nm at 60 C followed by 4 h condensation at 50PC.This option is used forgeneral applications such as outdoor furniture fabrics, tent material, etc.
8.2.2 Option 2,Thermal Shock Applications: 8h Uv at an irradiance of 0.77W/m2 @ 340 nm at 60C; followed by0.25 h water spray; followed by 3.75 hcondensation at 50 C.This option hasbeen used for architectural and other applications where thermal shock may bean issue.
8.2.3 Option 3,Automotive Exterior: 8h UV at an irradiance of 0.72 W/m @340 nm at 70°C followed by 4 h condensation at 5o C.UV irradiance may bemonitored and maintained by the manualmethod or by the feed-back-loop methodas described in SAE J2020.
8.3 The use of these cycles does not imply, expressly or otherwise, an accelerated weathering test, nor is this method
restricted to the use of these cycles.Thedegree of correlation to any actual out-door weathering exposure must be determined by quantitative analysis.
9.Standards of Comparison
9.1 Standards for comparisons can bemade of any suitable textile material where a history of strength degradation orcolor change rates are known dependingupon individual test needs.They must beexposed simultaneously with the test
specimen to be investigated.The intent ofthese standards is to demonstrate unifor-mity between separate machine and testruns.When test data of the exposed stan-dards differ by more than 10% from theknown data, the test machine operatingconditions must be thoroughly reviewedand any malfunctions or defective partscorrected.The test is then repeated. If thedata still differ by more than 10% fromthe known data and there is no evidenceof machine malfunction, then the teststandard should be questioned and re-evaluated.Test data obtained with ques-tionable standards must be treated withcaution and resolution provided withquantitative analysis.
10.Procedure
10.1 Maintain and calibrate the apparatus in accordance with the manufacturer’s recommendations.
10.2 Before beginning the exposuretest, bring all specimens, control and test,to moisture equilibrium in the atmo-sphere for testing textiles in accordancewith ASTM D 1776, Standard Practicefor Conditioning Textiles for Testing.Equilibrium is considered to have beenreached when the increase in mass of thespecimen in successive weightings madeat intervals of not less than 2 h does notexceed 0.1% of the mass of the specimen.Perform any necessary tests or evalua-tions necessary to establish a base line forcomparing the unexposed specimens tothe exposed specimens.
10.3 Specimen Mounting. Mount thespecimens in the frames which are supplied with the cabinet with the test surfaces facing the lamp. When the testspecimens do not completely fill theracks, the empty spaces must be filledwith blank panels to maintain the testconditions within the chamber.
10.3.1To provide rigidity, flexiblespecimens may be attached to a backingpanel made of aluminum or other noncor-rosive heat conductive material.AATCC TM186 pdf download.Weather Resistance