1、Designation:D414494(Reapproved 2014)Standard Test Method forEstimating Package Stability of Coatings for UltravioletCuring1This standard is issued under the fixed designation D4144;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This method covers procedures for testing the packagestability of coatings intended to be cured by ultravioletradia
3、tion.One procedure is given for clear coatings andanother for opaque fillers.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its
4、use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Summary of Method2.1 Specimens are placed in several containers,some ofwhich are subjected to an elevated temperatu
5、re while others arestored at room temperature.At specified intervals a specimen ischecked for evidence of gelling.Clear materials are held inglass containers so they can be examined visually withoutopening to prevent contact with air which might inhibitpolymerization.Opaque materials are checked by
6、opening onecan,probing the contents with a spatula to determine the extentof any polymerization,and then discarding that specimen.3.Significance and Use3.1 Coatings intended to be cured by ultraviolet radiation,especially those involving free radical chemistry,tend topolymerize during storage.It is
7、of interest to determine howwell a formulation resists this effect.Many factors influencethe storage stability of a composition.The procedures de-scribed here are intended to improve the precision of deter-mining this property.Because the effects of resins,monomers,photoinitiators,synergists,stabili
8、zers,or pigments can alter therelation between elevated and room temperature stabilities,anycorrelation of performance at two different temperatures ispossible only with a given formulation and,therefore,is usefulonly for quality control.4.Apparatus4.1 Oven,maintained at 50 6 2C.4.2 Glass Jars,wide-
9、mouth,115-mL(4-oz),with 38-mmclosures.4.3 Cans,lined,115-mL(4-oz),friction top,with lids.4.4 Spheres,glass or porcelain,7 to 10-mm diameter.5.Procedure5.1 Clear Coatings:5.1.1 Fill three 115-mL(4-oz)wide-mouth jars to 6 mm(14in.)from the top.Add a small glass or porcelain sphere to eachcontainer and
10、 put the lids on tightly.5.1.1.1 The amount of head space in a jar or can is criticalbecause the volume of air in contact with the sample has aneffect on the rate of polymerization.The stability is also relatedto the ratio of the area of liquid-air interface to the volume ofliquid.5.1.2 Put two jars
11、 in an oven at 50 6 2C.Retain the thirdat a temperature,25 6 2C,and in the dark.5.1.3 Check an oven jar daily but do not open or invert.Rather,tip slightly,no more than 30,to determine the extentof polymerization by noting the mobility of the sphere.Whengelling is noticed,check the second jar to con
12、firm.5.1.4 Record the duration of the test in days.Indicate thelast day the sphere is mobile followed by the first day it isimmobile,and if the days are not consecutive,why the intervaloccurred.5.1.5 Check the jar stored at room temperature every weekbut do not open or invert.Tip slightly,no more th
13、an 30,todetermine if the sphere is immobile.5.1.6 Record the number of weeks not gelled followed bythe first week the sphere is immobile.5.2 Pigmented(Opaque)Coatings:5.2.1 Fill twelve 115-mL(4-oz)lined cans to 6 mm(14in.)from the top and put the lids on tightly.5.2.1.1 See 5.1.1.1.1This test method
14、 is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints and Paint Materials.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved i
15、n 1982.Last previous edition approved in 2010 as D4144 94(2010).DOI:10.1520/D4144-94R14.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2.2 Put six of the cans in an oven at 50 6 2C.Retain sixcans at ambient temperature,25 6 2C.5.2.3 Af
16、ter one day remove one can from the oven,open,and probe to the bottom to determine if gelling is beginning.Discard the can after the test.Check one of the remaining canson the 2nd,4th,8th,16th,and 32nd days and discard aftertesting.By starting on a Monday all the testing will fall onnormal working days.5.2.4 Record the condition of the specimen each day tested,indicating the fractional amount of any gelled material present.5.2.5 After one week check one of the cans held at ambienttemperature by
