1、Designation: D4144 94 (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
2、, the 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 ultra
3、violetradiation. 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, assoc
4、iated with its 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
5、elevated temperature 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 mater
6、ials are checked by 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 topolymeri
7、ze during storage. It is 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,photo
8、initiators, synergists, stabilizers, 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, maint
9、ained at 50 6 2C.4.2 Glass Jars, wide-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
10、a small glass or porcelain sphere to eachcontainer and 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-
11、air interface to the volume ofliquid.5.1.2 Put two jars 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
12、the sphere. Whengelling is noticed, check the second jar to confirm.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 tempe
13、rature every weekbut do not open or invert. Tip slightly, no more than 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 (14 in.)fro
14、m the top and put the lids on tightly.5.2.1.1 See 5.1.1.1.1This test method 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.Cur
15、rent edition approved Dec. 1, 2014. Published December 2014. Originallyapproved in 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 States15.2.2 Put six
16、of the cans in an oven at 50 6 2C. Retain sixcans at ambient temperature, 25 6 2C.5.2.3 After 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 da
17、ys 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 ope
18、ning and probing to the bottom to determineif gelling is beginning. Discard the can after the test. Check oneof the remaining cans after 2, 4, 8, 16, and 32 weeks.5.2.6 Record the condition of the specimen after each testand indicate the fractional amount of any gelled materialpresent.6. Report6.1 R
19、eport whether the material was clear or pigmented andthe length of time it was stable as indicated by the occurrenceof gelation at both ambient and elevated temperatures. Reportthe age of the material when the test began, if it is known.7. Precision and Bias7.1 Precision:7.1.1 Clear Coatings:7.1.1.1
20、 At the elevated temperature, four of five cooperatorsreported a clear coating without inhibitor gelled on the 8th or9th day. Four of five cooperators reported a coating withinhibitor gelled on the 32nd day; the fifth reported gelation onthe 18th day.7.1.1.2 At room temperature four of four cooperat
21、ors re-ported no gelling at 32 weeks, with or without inhibitor.7.1.2 Pigmented Coatings:7.1.2.1 At the elevated temperature six of six cooperatorsreported a filler gelled at 8 days.7.1.2.2 At room temperature four of four cooperators re-ported various degrees of gelation after 32 weeks.7.2 BiasSinc
22、e there is no accepted reference material forthis test method, bias cannot be determined.8. Keywords8.1 stability; ultraviolet cureASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard
23、are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif no
24、t revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which
25、you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,Unit
26、ed States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 94 (2014)2
